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How To Succeed At Slurry Pumping
Описание: How To Succeed At Slurry Pumping Optimal transfer of two-phase solid-liquid flow (slurry flow) has long been a major industrial challenge. Slurry pumps are among the most common types of centrifugal pumps used to deal with this transfer issue. The approach of improving slurry pumps and consequently increasing the efficiency of a flow transmission system requires overcoming the effects of slurry flow such as the reduction in head, efficiency, and wear. This study attempts to investigate the changes in the pump head by modifying the slip factor distribution in the impeller channel. For this purpose, the effect of splitter blades on slip factor distribution to improve the pump head was investigated using numerical simulation tools and validated based on experimental test data. Next, an optimization process was used to determine the characteristics of the splitter (i.e., length, number, and environmental position of the splitter) based on a combination of experimental design methods, surface response, and genetic algorithm. The optimization results indicate that the splitters were in a relative circumferential position of 67.2% to the suction surface of the main blade. Also, the optimal number and length of splitter blades were 6 and 62.8% of the length of the main blades, respectively. Because of adding splitter blades and the reduction in the flow passage, the best efficiency point (BEP) of the slurry pump moved toward lower flow rates. The result of splitter optimization was the increase in pump head from 29.7?m to 31.7?m and the upkeep of efficiency in the initial values. The effect of solids on a centrifugal horizontal slurry pump performance is a major concern to the design of slurry transportation system. In the present study, the multiphase modeling of centrifugal slurry pump is performed using two models, Mixture and Eulerian-Eulerian multiphase. Sliding mesh approach is employed for unsteady simulation of the pump. The accuracy of the simulations is ascertained by comparing the performance characteristics of the pump obtained numerically and experimentally. Experimental results are obtained by measurements in a pilot plant test rig with three different mean size sand particulate slurries. The Eulerian-Eulerian multiphase model predicted the effect of the solids on pump performance close to the experimental results as compared to Mixture model. The obtained accuracy with Eulerian-Eulerian model for predicting the effect of solids on head and efficiency is around ±2% and ±3%, respectively. The predicted results using Eulerian-Eulerian model confirm that the head and efficiency of the pump decrease with the increase in particle size and concentration. The particles of high specific gravity show less reduction in head and efficiency of the pump. Further, the effect of variation in particle size and concentration on the flow field in the impeller and casing has also been analyzed at best efficiency point operation. Non-homogeneous suspension of particles inside the blade channels and casing passages is examined. The particulate concentration is observed higher near the impeller back shroud, pressure side of the blades, and non-suction side of the casing as compared to other locations. Plants often must handle slurries in applications ranging from processing to wastewater treatment. Dealing with such mixtures of liquid and solids is challenging and difficult. Some key elements in slurry pumping are the size and nature of the solids in the liquid and the kind of the abrasive wear they cause. Another is the corrosiveness of the liquid or the mixture. Sites frequently rely on centrifugal pumps for slurry services. These pumps (and their associated piping systems) need special provisions that call for a detailed knowledge of the solid and slurry properties to prevent wear, corrosion, erosion and other adverse effects such as settling of the solids. Specifying the optimum combination of speed, geometry and materials requires properly balancing often conflicting pump priorities; this demands consideration of stable operation, maximum wear life, operational flexibility and minimal energy consumption. In this article, we’ll cover practical guidelines and rules for centrifugal pumps for slurries. We’ll also discuss key operational features, material selection and other considerations. Tailored Pumps Horizontal centrifugal pumps usually are used for slurry services, although vertical and other types of pumps are favored for some specific applications. Centrifugal pumps for handling slurries have features tailored to the particular service that reflect the corrosive or abrasive nature of the slurry and the solids concentration. These may include choice of materials, use of liners and even different driver sizing. The first major requirement of a mining slurry pump is to provide adequate service life. Erosion and corrosion effects of slurries, such as the impingement of high velocity flow of liquid/solid mixtures, are really challenging. In many applications, some solids in the mixture are larger than usually specified particles; so, the pump should be able to pass them without any damage or operational problems. As a result of such requirements, a vertical slurry pump often is larger than its clear liquid counterpart. Moreover, it generally sacrifices efficiency, both maximum efficiency and efficiencies over the whole operating range, in exchange for the ability to achieve good operation in these challenging services. Because wear is a function of velocity, a slurry pump’s speed should be as low as possible; units usually operate at 1,200 rpm or slower. Often, direct coupling between the pump and a low-speed electric motor or other driver makes most sense. On the other hand, many other applications favor gearboxes to meet the desired speed and duty point. In services requiring variable flow, variable frequency drives are used to provide the necessary continual speed changes. Although the emphasis on a ceramic slurry pump tends to be on the size and percentage of solids to be pumped, corrosion resistance is also an important factor for material selection in many applications. In such cases, the material chosen must provide an adequate combination of both erosion and corrosion resistance. For slurry services, a pump operating on the left of the pump performance curve or at the best efficiency point (BEP) is usually preferred; as an indication, the rated point should lie somewhere between 85% and 100% of the BEP point. The performance curves of many centrifugal pumps are based on handling water. So, to obtain the performance characteristics for these slurry centrifugal pumps, you must modify the results for the presence of solids. Many correlations and correction methods exist for predicting the performance of centrifugal pumps when handling slurries; these account for factors such as individual effects of particle size, particle size distribution, specific gravity and concentration of solids. They usually provide a head reduction factor and efficiency reduction factor for slurries compared to clear water. However, every pump has unique service-specific factors for a given application. You should verify these by experiments. For slurry services, a pump operating on the left of the pump performance curve or at the best efficiency point (BEP) is usually preferred; as an indication, the rated point should lie somewhere between 85% and 100% of the BEP point. The performance curves of many centrifugal pumps are based on handling water. So, to obtain the performance characteristics for these slurry centrifugal pumps, you must modify the results for the presence of solids. Many correlations and correction methods exist for predicting the performance of centrifugal pumps when handling slurries; these account for factors such as individual effects of particle size, particle size distribution, specific gravity and concentration of solids. They usually provide a head reduction factor and efficiency reduction factor for slurries compared to clear water. However, every pump has unique service-specific factors for a given application. You should verify these by experiments. Wear, Erosion And Corrosion Major factors that influence wear include the following: ? details of erosive particles (material, size, shape, etc.); ? concentration of solids; ? fluid velocity and particle velocity; and ? hydrodynamic properties of the flow (Reynolds number, etc.). Turbulent flow analysis usually isn’t applicable for slurry pumps because the presence of solid materials will directly influence the turbulence parameters. The mechanisms of turbulence become a complex problem particularly for dense slurries. This, combined with the nature of the flow inside a slurry pump, which is characterized by unsteadiness as well as deformed velocity distribution patterns, cause a very chaotic situation. However, some simple rules have been verified both in theory and experiments. For instance, the erosive wear rate is proportional to the flow velocity. It also depends on the solids concentration; as that concentration increases, so, too, does the wear rate. In addition, the sizing and specific gravity of solids in the slurry affect wear. As a very rough indication, in medium and low concentrations, the mechanism of erosion resembles cavitation erosion. Here are some observations about a slurry pump that operated for a short period with low concentration slurry and then with a moderate concentration one. With the slurry at low concentration, the suction side of the blade showed very limited erosion at the leading edge while the rest of the surface was nearly unscathed. Most of the erosion of the back shroud was concentrated in the eye of the impeller and around the leading edge of the back-shroud corner. The maximum erosion appeared on the leading edge and towards the back shroud of the impeller. This pump, operated with a relatively higher concertation slurry, showed a similar erosion pattern — with the only notable difference being that the region close to the back shroud was more heavily eroded. Unfortunately, here and more generally, theoretical studies don’t properly predict the level of erosion. To cope with wear, pump designers generally rely on two options: use of thicker components or liners. In the first approach, designers apply thickness allowances depending on estimates of erosion and corrosion of each part or component. Such pumps feature thick sections for all parts and components in contact with slurry including impeller and casing; those elements subject to high speed flow of slurry or solid impingements receive a greater thickness allowance. In the second method, the designers provide wear liners on pump internals; many such pumps are fully lined internally. A lined pump, if properly done, can allow use of a wider variety of materials and also cost-effective application of exotic (expensive) materials. An unlined pump may offer lower initial capital cost. However, a properly lined pump usually affords a greater number of material choices, which may result in longer wear life and lower replacement spares cost. The lined pump also is inherently safer from a pressure containment standpoint because, in pumps relying on added thickness for components, corrosion and erosion over time might reduce the thickness to below the original value. Large clearances within the impeller and casing allow for the passage of large diameter solids, while also reducing internal velocities and corresponding wear. On the other hand, proper design and installation of liners can pose challenges — many pumps with liners have failed because of such inadequacies. The materials used for wear components are hard metals, elastomers and, to a lesser extent, ceramics. Hard metals and ceramics combat erosion due to their high hardness values. Elastomers combat erosion by absorbing the energy of an impacting particle due to their resilience and tear resistance. Elastomers often can provide better erosion resistance in some applications. As a very rough indication, these are services where particle size is smaller than 250 microns, impeller tip speed is within the limits of the application of elastomers, and there’s no risk of large particle damage. Elastomer-lined pumps have been successfully used in numerous slurry services. Many metals have been used for slurry pumps. The ASTM A532 standard for abrasion-resistant cast irons covers the three basic types — “Martensitic White Irons” (Class I), “Chromium-Molybdenum White Irons” (Class II) and “High Chrome Irons” (Class III). These materials, which are made by melting processes, have been alloyed to achieve high resistance to abrasive wear. The bulk hardness of these alloys depends on many factors and parameters — for instance, not only upon the carbide and matrix type but also upon the volume of the carbides within the matrix. For slurry applications with small particles, microstructure, with smaller inter-carbide spacing, is particularly important to minimize erosion of the softer matrix. For slurry services with medium to large particles, the bulk (combined) material hardness is key. For applications with very large particles, fracture toughness of the matrix is important. Impellers These tend to be larger than their clear liquid counterparts. Achieving a given head and providing more material for wear purposes requires a lower impeller speed. Minimizing speed and maximizing wear life of both the impeller and suction side depends upon a proper configuration. High wear applications usually call for closed-type impellers. In applications with coarse particles, expelling vanes on the face of the front shroud make sense. These vanes prevent large particles from becoming trapped between the impeller and suction side liner and minimize recirculation. The benefit is reduced gouging and recirculation wear at the expense of a 2–3% drop in efficiency. In addition, expelling vanes often are used on the back shroud of the impeller in coarse particle applications to prevent the trapping of large particles between the impeller and back liner. In this location, they also serve to decrease the forward axial load by lowering the pressure acting on the back shroud and beneficially reducing the pressure at the hub. The decreased axial load improves bearing life. All these effects also cut the pressure differential at the shaft seal and reduce the tendency for slurry leakage from the pump. As with expelling vanes on the front shroud, back vanes usually absorb 2–3% of efficiency. To combat wear and allow for passing large diameter solids, many slurry pump impellers feature fewer but thicker main pumping vanes. Both of these factors further contribute to reduced efficiency compared with clear liquid impellers. While a clear liquid impeller usually has five to nine vanes, most slurry pump impellers have two to five. Applications requiring large particle passing often employ pumps with two or three vanes. Slurry pumps use short blocky vanes in contrast to the thin long-length, long-wrap vanes found on high efficiency pumps for clear liquids. Sumps And Storage Tanks Slurry pumps usually require sumps or suction tanks to act as suction source or intermediate storage for slurries. However, lack of detailed knowledge about the slurry pump’s behavior and sump hydraulics often leads to oversizing. The larger the sump or storage tank, the more likely it may become a settling tank for solids. For some services, the accumulation of solids leads to other problems, for instance, the build-up of harmful gases, and requires periodic desludging of the sump or tank, which increases operating costs and reduces overall safety and reliability. The optimal volume of suction storage, in this context, should prevent the settling of solids while avoiding problems for pump operation.
Дата Публикации: 30-12-21
Are Electric Scooters the Future? How Do They Actually Work?
Описание: Are Electric Scooters the Future? How Do They Actually Work? If you’re a particular age, then you might have memories of riding a new energy scooter. Those flimsy, two-wheeled scooters that gave you freedom on the sidewalk in front of your house before your acquisition of a bike opened up the whole neighborhood. Until recently, that image of a scooter as a nothing more than a child’s toy was the one most people carried. Now, several companies, such as Bird, LimeBike, and Spin, are out to change that perception. They are banking big on the idea that the small, compact e-scooter is a viable personal transportation device. But is it? Let’s take a look at where e-scooters are at today, from their fundamental appeal to how they work to their practicality beyond ordinary weekend fun. Although manual and electric kick- or push-start scooters have both been around for some time, the popularity of the latter has risen steadily over the past two decades. Perhaps the central development in the design and marketing of today’s e-scooters is children are no longer the primary audience. Make no mistake, the targets are still young. They just happen to have a different set of priorities. College students on campus. Young professionals who live and work in urban environments. People looking for alternative means of transportation in those same cities. Each of these groups offer a market segment that tends to eschew the norms and traditions of the past. Zipping around town on a low-speed, zero-emission scooter certainly caters to those demanding alternatives. With a unifying factor that everyone over a certain age will probably look a little goofy riding one, it’s easy to see the appeal. It also doesn’t hurt that electric scooters come across as simple and easily accessible devices that are even easier to operate. E-scooters, much like their non-powered siblings are about as straightforward as it gets when it comes to personal transportation devices. In their simplest form scooters are composed of a narrow platform or deck, t-stem handlebars with a throttle and hand brakes, two wheels (although some models come with three or four), and front and rear suspension. Most scooters are fold-able, and some models also include a seat. When it comes to variation, scooters are what they are. Alter the design too much, and they become an entirely different form of transportation. However, they do possess a few key areas where a slight difference makes a significant impact on performance. It begins and ends with the battery. Battery You’ll find one of three battery types in the manufacturing of e-scooters, Nickel Metal Hydride, Lead-Acid, and Lithium-ion: Nickel Metal Hydride (NiMH) A long-term market mainstay, NiMH batteries carry the middle ground between the well-known lead-acid and the newer Lithium-ion. NiMH batteries hold a longer charge versus a lead-acid version but are heavier than the Lithium-ion variety. Ultimately, these work well as a practical, cost-conscience alternative to the pricey Lithium-ion. Lead-Acid The long-standing workhorse of rechargeable batteries, lead-acid batteries have yet to lose their place as the preferred starter for automobiles and the power source for golf carts. Though a bit cumbersome for widespread use, you’ll still find plenty of these weighty and very inexpensive batteries in larger scooters. Lithium-ion The newest battery technology for e-scooters is also the most expensive, but for very good reasons. The Lithium-ion tech is more powerful, holds a charge far longer than either the lead acid or NiMH, and do so in a much more lightweight package. More and more longest range electric scooter are featuring these batteries and as the tech and production improve, so should the price. The allure of the e-scooter both as a toy and as a potential vehicle for commuting is the simplicity of the whole endeavor. The other facet of its practicality, especially for adult professionals is its limitations. Due to the diminutive build of scooters, the size of the onboard battery is typically smaller than a cable box, which means the overall performance of the rideable has its limits. Nowhere is this impact felt more than by the capacity, range, and speed. More so than most other electric rides, a scooters range and speed is dictated directly by the capacity it carries and the terrain it traverses. With few exceptions, most scooter manufacturers provide an ideal set of circumstances to reach optimal range and speed, usually defined as a 165 lb rider on a smooth flat surface. Rideshare scooters max out at 15 mph. Though most e-scooters can top out at speeds close to 20 mph (with some newer models flirting with the 30- mph mark) rare is the time an adult rider can achieve this mark. This works well for riding mini electric scooter in an urban environment since it lends itself to a more comfortable, confident rider. Plus, anything faster typically invites accident and potential injury. Safety As with most personal e-vehicles, such as hoverboards, self-balancing unicycles, and Segways, the individual riding the device most often determines just how safe it is. However, staying upright on a scooter is less fraught with danger versus those other options. The primary safety issue with scooters is when you place them among large groups of pedestrians and cars, which is happening now in a number of major cities across the U.S. This intermingling of people on foot and those scooting by at a top speed of 15 mph has created an uptick in accidents between the two, though reliable data does not yet exist on the exact numbers. Beyond possible run-ins with non-riders, another primary safety concern revolves around the attire of the actual riders. Though every scooter manufacturer and ride-sharing company recommend the use of a helmet, and many cities dictate the wearing of headgear, very few e-scooter riders do so. As we noted in the opening, several startups are beginning to flood major metropolitan areas with hundreds of rent by the minute scooters. One of these groups, Bird, is helmed by Travis VanderZanden, a former executive at ride-sharing giants Lyft and Uber. Others in the marketplace include LimeBike, who also offers bikes for rent, and Spin, who has a similar business model with bikes and scooters. The appeal of the scooter-sharing programs is the cost and convenience. Powered by an app, after you enter basic info and agree to terms, you can unlock the high speed electric scooter for adult via a simple scan. The app can also guide you to the closest ride. Since they are dock-less, you can find one anywhere and leave one anywhere. When it comes time to pay, depending on where you need to go, most rides will run you fewer than $5. Bird, for example, charges a $1 unlocking fee and then 15 cents for each minute of use. For a fifteen minute trek, that will run you $3.25. Many rides are far less than that. While it’s been a massive plus for those seeking alternatives to walking or riding mass transit, many cities have been less than receptive. It doesn’t help that in several locales the scooter-share companies have unloaded hundreds of the devices throughout town with no permit and barely any notice. Several municipalities have responded with demands for the groups to remove the vehicles, or they would do it for them. Another issue popping up involves either the lack of experience or lack of knowledge of the riders. In the majority of cities across the U.S., e-scooters fall under the same ordinances that govern the use of bicycles. While most bike riders understand the basic tenets they are expected to follow, its uncertain how many scooter renters do. For example, with very few exceptions, scooters must be ridden in bike lanes or city streets where the former doesn’t exist. Yet, numerous reports abound that plenty of e-scooters are traversing city sidewalks, instead of staying below the curb. In addition, the use of a helmet is practically a universal requirement for any two-wheeled vehicle, whether it’s powered manually, electronically, or with gasoline. Several companies have begun to offer helmets for a nominal fee to their regular, in-town adapters. Unfortunately, the “get it and go” nature of renting an e-scooter dictate that most users won’t have headgear handy when they are ready to ride. So many go without the proper protection. As is the case for new technologies and new ways of addressing old problems, it’s a tricky balancing act for everyone involved. To that point, we should note two major U.S. cities in New York and Boston have explicitly said no to the experiment, while Austin, TX has found some resolution, after hammering out regulatory requirements for the operators. With both successes and failures, time will tell if the e-scooter providers and the cities in which they hope to operate can discover a happy medium. Few things in this world have ever made the jump from child’s toy to adult necessity. With people clamoring for travel alternatives and lukewarm response from local governments, it will be interesting to see if the scooter-sharing industry has the wheels to carry it beyond a millennial fad. If nothing else, it’s a noble attempt to make un-walkable cities a bit more comfortable to navigate and to alleviate some of the stress and congestion of urban living. Regardless of how that turns out though, a weekend scoot around the neighborhood with the breeze in your hair and a pair of battery-powered wheels at your feet will never go out of style. The easing of lockdowns has highlighted the importance of individual, emission-free, socially distanced transport as governments try to prevent spikes in car use and pollution. But the story of e-scooters is one of both a popular tech gadget and a contentious form of transport. While they offer a seemingly fun and environmentally friendly option for short journeys, a range of questions about their safety and sustainability have emerged in the past two years. So how did e-scooters go from risky tech novelty to a green travel solution for the coronavirus recovery? And are they really so good for the planet? E-scooters have been available to privately buy for over a decade but many remain prohibitively expensive. It took the affordable, accessible option of shared, dockless models – which can be rented by the minute using a smartphone app – for their popularity to skyrocket. In 2018, shared e-scooter startups Bird and Lime rapidly introduced them to US cities (sometimes without permission). Soon after, the companies – along with a proliferation of other startups, including European-based Voi and Tier – began to rapidly expand across cities internationally. Now, e-scooter sharing schemes are available in more than 100 cities, across at least 20 countries, from Chile to South Korea to New Zealand – although Europe and the US continue to dominate in terms of use. Research suggests that by 2024, 4.6 million shared e-scooters will be in operation worldwide, up from 774,000 in 2019. Regulation and legislation measures vary internationally. In many countries, they are technically illegal. Until recently they have been in the UK too, but in May, the government announced that shared e-scooter trials would be brought forward by a year and rolled out nationally. As of 4 July, rental e-scooters are legal on the UK's streets. Meanwhile in Jakarta, Singapore and Shanghai, e-scooters are still banned on roads and pavements entirely, while Paris has banned riding and parking them on pavements. Other cities have speed limits, restrictions on scooter numbers or rules on where they can be used and parked. Green credentials Safety is not the only issue, though: e-scooters have come under increasing scrutiny for their environmental impact. Although shared models are emission-free at the point of use, the process of manufacturing, moving and managing them results in greenhouse gas emissions – which increase if they have a short lifespan. Most shared e-scooters need to be collected, charged and redistributed regularly, often using fossil-fuelled vehicles. A 2019 study by researchers at North Carolina State University, taking into account emissions produced by making and moving e-scooters, suggested they typically produce more emissions per passenger mile than a standard bus with high ridership, an electric moped, an e-bike or a regular bicycle. Such findings are echoed by research from the Lufthansa Innovation Hub ranking estimated carbon emissions of various transport types, which suggests average emissions of dockless e-scooters are higher than those of trains, buses, e-bikes, electric and hybrid cars and even petrol-powered scooters. Such emissions can be reduced through reducing the number of trips by operational vehicles to ferry scooters around cities, using emission-free vehicles when they do so and increasing scooter lifespan. Currently, shared e-scooters are meant to last between one and two years, but due to both accidental and deliberate damage, many last much less time than that. Looking at Louisville, Kentucky, Quartz estimated the average lifespan of a Bird e-scooter was roughly 29 days. Many believe the dockless set-up is to blame. Dockless bike-share schemes were heavily criticised when "mass graveyards" of redundant bikes appeared – could e-scooters be heading the same way?
Дата Публикации: 30-12-21
What’s glass, and how are modern-day researchers enhancing its properties?
Описание: What’s glass, and how are modern-day researchers enhancing its properties? You’d think we would know everything there is to know about decorative coloured glass by now. It’s been around for thousands of years, and it’s practically everywhere: in the walls of high-rise commercial buildings, in the windows of houses, in the windshields of automobiles and airplanes. Then there’s fine crystal, cookware, bottles, jars, and yes, chemical glassware—just to mention a few other products made of glass. Still, just this year, researchers at Corning debunked a popular urban legend about glass. The legend states that glass is a supercooled liquid and points to stained glass windows in medieval cathedrals as evidence. Because glass flows slowly over time, the legend goes, some of those windows end up thicker at the bottom than at the top. That just ain’t so. The researchers used modeling and measurements and determined that stained glass of the type found in Westminster Abbey actually flows a maximum of about 1 nm over a billion years (J. Am. Ceram. Soc. 2017, DOI: 10.1111/jace.15092). The viscosity of glass—actually an amorphous solid—is too high for humans to observe its flow during their time on Earth. The thicker window edges may simply be an artifact of medieval glass processing. Why glass is still capturing the minds of scientists and innovators depends on whom you ask. Arun K. Varshneya, president of Saxon Glass Technologies, which specializes in strengthening glass for the pharmaceutical and other industries, ticks off a long list of properties that make the stuff so useful. Beyond being transparent, it also stands up to wind, rain, snow, intense sunlight, and large swings in temperature, he says. It’s also chemically resistant and recyclable, and many varieties of glass are relatively inexpensive. Richard K. Brow, a materials scientist at Missouri University of Science & Technology, says he finds glass captivating aesthetically. Some 40 years after delving into glass research, Brow remains fascinated with the way the molten material flows and forms an enormous variety of shapes, from microscopic spheres and fibers to large sheets and plates. “Glass is so useful,” he adds, because “the composition can be tuned broadly to tailor its properties and performance for such a wide range of applications.” In addition to the common ones “in daily use by virtually all humanity,” some hot melt glass applications, such as fiber-optic cables for telecommunication and microscope and telescope lenses, “dramatically expand the frontiers of industry and science,” Robert Weisenburger Lipetz says. He’s the executive director of the Glass Manufacturing Industry Council, a nonprofit trade association. And glass isn’t just useful; it’s also big business. Lipetz says in the U.S. alone, glass manufacturing is estimated to be a $22.5 billion market. People began using glass long before markets even existed. Early humans used obsidian—molten lava that cooled quickly—to make simple cutting tools and arrowheads. And although evidence from beads and other archaeological finds indicates that people figured out by 4,000 B.C.E. how to form glass coatings (glazes) by melting silica, the main component of sand, it would be another 2,500 years until ancient Mesopotamians got the hang of making hollow glass vessels, which they used for storing oils. Around 200 B.C.E., Phoenicians developed the blowpipe and associated glass-blowing techniques, advances that historians say were the most important ones in the development of glass manufacturing. Those procedures enabled early glassmakers to shape molten glass into numerous useful and decorative products, which were easily transported and widely traded. The main ingredients in glassmaking were widely available back then, and the recipe hasn’t changed much since that time. Sand—the source of silica (SiO2)—tops the list, typically coming in around 70% by weight. Other components include sodium carbonate (Na2CO3), which is known as soda ash, and limestone (CaCO3), which is plentiful in seashells. Heating these materials together yields a molten mixture that cools to form a type of security wire glass known today as soda-lime glass. That’s the most common and least expensive type, accounting for roughly 90% of all manufactured glass. Through trial and error, glassmakers learned to modify the composition of glass to tune its properties for various applications. Soda-lime glass, for example, does not tolerate high temperatures or sudden changes in temperature. Adding a few percent of sodium borate to the melt incorporates boron oxide into the resulting glass. That material, a borosilicate glass, benefits from a lower coefficient of thermal expansion than soda-lime glass has, enabling the boron-containing form to withstand large and sudden temperature changes. One particularly well-known borosilicate glass is Pyrex, the Corning family of heat-resistant bakeware, measuring cups, and other protective coating glass odds and ends for the kitchen. That line of commercial products, which recently celebrated its 100th anniversary, is also highly resistant to corrosive chemicals. The combination of heat resistance and resistance to damaging chemicals makes Pyrex flasks and pipelines well suited to laboratory and industrial use. Today’s Pyrex kitchen products are no longer made of borosilicate glass. Corning sold that division in 1998 and the new company switched to tempered soda-lime glass. Lead glass is another variety of the familiar material that has been known for a long time. This form contains 20% or more lead oxide, boasts a high refractive index, and is relatively soft. Those properties make it sparkle, appear brilliant, and resist fracturing—all of which adds to the allure of fine goblets and other types of luxury lead glassware. Unfortunately, those beautiful goblets and decanters can pose health hazards due to lead leaching, according to the U.S. Food & Drug Administration. Glass manufacturers have come up with many other glass formulations and continue to develop novel compositions and processing methods for custom applications. For example, Missouri-based Mo-Sci is developing a cottonlike bioactive borate glass for animal and human use that heals chronic skin ulcers and deep wounds. The nanofibrous material, which has antimicrobial properties, releases bioactive ions in the wound. The ions stimulate blood vessel growth and promote healing of soft and hard tissues. Color blindness is another medical problem benefiting from a glass-based solution. Worldwide, millions of people are unable to distinguish various colors, especially reds from greens, under normal lighting conditions. Researchers at Enchroma designed stylish eyewear with custom-made lenses that filter select wavelengths from ambient light and help restore this component of vision to wearers who would otherwise be color-blind. As useful as glass is, it would be even more useful if pieces of the material didn’t break easily. That shortcoming led Varshneya of Saxon Glass to develop an ion-exchange process to strengthen glass cartridges used in EpiPen epinephrine injectors, which are used for treating severe allergic reactions. The procedure replaces some of the sodium ions at the glass surface with larger potassium ions. The difference in ion size leads to compressive forces that toughen the surface by blocking the routes along which cracks could otherwise propagate. That treatment drastically reduced the number of EpiPen cartridges that broke during injection. A related ion-exchange process lies at the heart of Corning’s Gorilla Glass, a chemically strengthened aluminosilicate material found in roughly 5 billion smartphones, tablets, and other portable electronic devices. Corning says a sheet of the newest version of the product less than 1 mm thick can survive 1.6-meter-high falls onto a rough surface 80% of the time. Manufacturers are now beginning to use the specialty glass for automobile windshields. As industry scientists march forward in the development of new types of glass for tough portable electronics, data-dense computer hard drives, and high-capacity solid-state batteries, one thing’s for sure: Despite its advanced age, glass isn’t nearing retirement anytime soon. To reach you, these words were encoded into signals of light moving about 125,000 miles per second through fiber-optic cables. These lines, splayed out across mountains and oceans, are made of hair-thin glass 30 times more transparent than the purest water. The technology was made possible in part by a team from Corning Incorporated. In 1970 they patented a type of cable that could transmit large amounts of information long distances, building on decades of work by other researchers. Assuming you’re reading this on a smartphone, you also owe a debt to Steve Jobs, who in 2006 asked Corning to make a very thin, strong screen for his new product, the iPhone. The result, Gorilla Glass, now dominates the market for mobile devices: Phones made with the fifth generation of this product can be dropped onto a rough surface from a height of five feet (selfie height) and survive 80 percent of the time. That’s just the start. Without glass, the world would be unrecognizable. It’s in the eyeglasses on your face, the lightbulbs in your room, and the windows that let you see outside. But despite its ubiquity, there’s still some debate within the research community about how to define “glass.” Some tend to emphasize its solid qualities, others its liquidity. Unanswered questions abound, like what makes one type of glass stronger than another, or why certain mixtures produce their unique optical or structural properties. Add to this the nearly infinite varieties of glass—one database lists over 350,000 types of currently known glass, though in principle the number of mixtures is limitless—and you get a surprisingly large and active field of research that regularly produces astounding new products. Glass has shaped the world more than any other substance, and in many sneaky ways, it’s the defining material of the human era. “We’ve been making glass for thousands of years, and we still don’t have a good idea of what it is,” says Mathieu Bauchy, a ceramic printed glass expert and materials researcher at UCLA. Most glasses are made by heating and then quickly cooling a mixture of ingredients. In the case of flat glass, which makes up windows, that mixture may include sand (silicon dioxide), lime, and soda. Silicon provides the transparency, calcium provides the strength, and soda reduces the melting point. The swift cooling process doesn’t allow for atoms to form a regular pattern, explains Steve Martin, a glass scientist at Iowa State University. That helps explain why glass is neither a crystalline solid nor a liquid, but rather an atomically disordered (or amorphous) solid. The atoms within want to reassume a crystal structure, but typically cannot because they are essentially frozen in place. You might have heard that cathedral windows flow over long periods of time, hence why some are thicker at the bottom. That’s false: Such windows were made that way, due to a manufacturing technique that involved spinning molten glass that created uneven patches. But glass does move; it just does so very slowly. A study published last year in the Journal of the American Ceramic Society estimated that room-temperature cathedral glass would take over 1 billion years to flow a single nanometer. Though natural volcanic glasses like obsidian were fashioned into tools early in human history, glass was probably first manufactured in Mesopotamia more than 4,000 years ago. Likely, it was developed as an offshoot of ceramic-glaze production. The technique soon spread to ancient Egypt, and the first glass objects consisted of beads, amulets, and rods, often colored with added minerals to look like other materials, says Karol Wight, the executive director at the Corning Museum of Glass. By early in the second millennium b.c., craftsmen began making small vessels like vases. Archaeologists have unearthed cuneiform tablets that spell out the recipe for such materials, but these were written in cryptic language meant to conceal trade secrets, Wight adds. Glass had already become a serious business by the dawn of the Roman empire. The writer Petronius recounts the tale of a craftsman presenting Emperor Tiberius with a piece of allegedly unbreakable glass. Tiberius asked the craftsman, “Does anyone else know how to blow glass like this?” No, the craftsman replied, thinking he’d made it big. Without warning, Tiberius had the man beheaded. Although Tiberius’s motives remain mysterious, one can imagine such an invention would’ve disrupted Rome’s important glass industry, the first of its kind.
Дата Публикации: 30-12-21
Elevate Your Outdoor Space With These Planter-Tree Combos
Описание: Elevate Your Outdoor Space With These Planter-Tree Combos For all that your houseplants do for you—like cleaning the very air you breathe—the least you can do is give them a beautiful home. For showstopping indoor planters that won’t break the bank, we turned to some of our most loved ceramists and home decor brands for inspiration. These innovators have been cooking up some truly original house planter designs for succulents, small plants, and leafy greenery that’ll match any decor. Prefer a classic look? O.G. terra-cotta planters now come in sleek modern shapes. Looking for something flashy and modern? Shiny metal planters will add a glow. Just need a pop of color on the windowsill? There’s a hyper blue ceramic planter for that. And may we suggest that, if you do have that itch for a decor update, new plants (and, obviously, plant pots!) are really the best place to start. Now that we’re all spending more time indoors, the jolt of green will add some much-needed energy to your space and the lush accents will liven up any living room, tabletop, or DIY office. Even better, our favorite planters of the season range from the cost of a takeout dinner (sans glass of wine!) to a new pair of Vans, so you don’t have to feel so guilty if your green thumb fails and your plant baby doesn’t survive the season. It happens. (But it doesn’t have to!) Ready for the easiest home upgrade of your life? Shop our selection of affordable indoor planters. THINK BIGGER THAN a crock of nasturtiums this year. “Potted trees can be magical,” said Andrew Pascoe, a floral designer in Oyster Bay, N.Y. “You can create privacy on a roof terrace. You can use two to flank a front door. A row of them is an instant hedge.” Choose a tree that typically attains a height of no more than 10 feet, and pamper it in every season, said Mr. Pascoe, who grew up in England’s mild climate, where potted plants commonly become permanent landscape features. “In spring and summer, trees will exhaust the food supply in the soil of a pot quite quickly, so feed them well with fertilizer, and water them daily,” he said. In winter, move pots out of danger of harsh winds and wrap them in burlap to protect roots from freeze-thaw fluctuations. Paired with the proper planter, a tree can become a living sculpture to artfully transform your garden year-round. Mr. Pascoe matches petite trees with new-to-market planters to make the most of both. “There’s something very Gothic about the design of this light planter” with its repeating pattern of pointed arches, said Mr. Pascoe. Pairing it with the frothy, very pale flowers of a miniature Cinderella crabapple tree would create “a classic blue-and-white palette—my favorite,” he said, adding that the planter’s sleek, aluminum surface updates the look. With long, slender branches that reach up and out like thin, curving fingers, Malus x ‘Cinzam’ “still looks enchanting in the winter when it has no foliage,” he said. Oomph Ocean Drive Outdoor Planter in blue, from $1,575, chairish.com “This is a very traditional metal planter, with its little feet and the rings on its sides, and would look lovely if you paired it with the formal shape of a holly trained as a topiary,” Mr. Pascoe said. Ilex ‘Castle Spire’ can be clipped to encourage it to spiral upward as it grows, like an evergreen church steeple. “For symmetry, I’d like to see two flanking an entryway.” In summer, its glossy leaves provide a deep green, and in winter, brilliant red berries. Aged Grey Square Planter by the Vintage Gardener, from about $190, societyhouse.co.uk For this plump, fluted container cast from a mix of crushed marble, rock and resin, Mr. Pascoe chose Prunus ‘The Bride,’ a flowering cherry tree with bouquet-worthy blossoms. “The shape of the pot reminds me of the shape of its delicate petals. Plus, the rough texture will play nicely against the pretty flowers when blooms in spring.” He recommends fertilizing the tiny tree in spring and judiciously pruning its crown to maintain a rounded, nosegay silhouette even when branches are bare in winter. Petal Garden Planter, from $650, pennoyernewman.com Third world maize (Zea mays L.) production is characterized by having extremely low yields, attributed in part to the poor planting methods employed. Maize planting in most third world countries involves placing 2–3 seeds per hill, with hills being roughly 30 cm apart. The variability in seeds per hill and distance between hills result in heterogeneous plant stands that are directly responsible for lower yields. Oklahoma State University (OSU) has developed a durable hand planter with a reciprocating internal drum that delivers single maize seeds per strike and that can also be used for mid-season application of urea fertilizer. The hand mountain planter is 1.4 m in length, 5.8 cm in diameter, and weighs 1.9 kg when empty. The seed hopper has the capacity to hold 1 kg of seed and the tip has a sharp pointed shovel which can deliver seed to a planting depth of 5 cm in no-till and tilled soils. The current prototype has been comprehensively tested and evaluated to deliver at least 80% single seeds (singulation), with 0% misses and work well across varying seed sizes (2652–4344 seeds/kg) and different operators. Using the OSU hand planter, third world maize producers with average yields of 2.0 Mg ha?1 could increase yields by 20%. Who doesn’t love to grow fresh salad greens, tomatoes and herbs? Unfortunately, growing veggies during the height of summer requires daily watering, which can quickly become a problem when you go away for vacation. In the past, we’ve hired the neighbor kid—sometimes he remembered, and sometimes we came home to withered veggies. But it turns out there’s a better way to beat the heat and keep your plants routinely watered- self-watering planters that you can leave for a week without watering. When we tasked our editors with designing some DIY self-watering planters, the results were incredible. The self-watering planter boxes themselves were gorgeous, they kept rabbits and other critters from munching on the greens, and we went for weeks on end without having to water. We watered three times all summer long (no kidding), and we had garden-fresh salads until frost. In this article, we’ll show you how to build self-watering planters for yourself. The secret of self-watering planters is in the perforated drain pipe. The total cost of this 3 x 6-ft. cedar planter was $330. If you use treated wood, the price would drop to about $250. And we used a thick EPDM pond liner, which cost $120. (You can buy thinner versions at home centers for about $35. All the other materials are available at home centers or garden/landscape centers.) To give the box a nice finished look, we routed the boards and sanded the faces and cap. We left the cedar unfinished, but you could seal yours. After we built the basic box, we moved the planter to its final position and then added the self-watering system, soil and plants. Even without the soil and plants, this DIY planter box is heavy! Self-watering planters are sometimes called “sub-irrigated planters” or SIPs, because your plants get to “sip” water whenever they want. Our version uses inexpensive perforated drain pipe with a fabric sleeve in the bottom of the planter. Once you fill the drain pipe reservoirs, they allow air to circulate and water to wick up to your plants’ roots whenever they need it. When plants are watered from below, the roots stay consistently moist, there’s less evaporation and you don’t need to water as much. The vinyl tubing allows any overflow water to drain. There are many commercial self-watering planters available—the EarthBox is a great optiom, but you can also easily make your own. For Material List, Cutting List, and Plant choices for containers, see Additional Information below. It's also important to note that we notched the flooring to fit. You can also fit the floor within the 2x2s as shown and let the liner span the gap. Choose a spot that gets at least six hours of sun. If your planter is against a wall, you can get by with less sun because of the reflected heat. A 4-ft.-wide planter is ideal for harvesting from both sides. Keep it to 3 ft. wide if you’re placing your unusual planter against a wall or fence. Line your planter with a “fish-safe” rubber membrane. It will prolong the life of the wood without leaching chemicals into the soil (and your food). You can buy fish-safe pond liners in different thicknesses and materials at home centers, garden centers and online retailers. Don’t use garden soil or a heavy potting soil in your raised garden. Use a light, fluffy “soilless” blend that will retain moisture without compacting or becoming waterlogged. You can also buy potting soil specifically formulated for self-watering planters. Mulch your containers to keep weeds down and to slow evaporation. For more great ideas for building sub-irrigated planters (SIPs), visit insideurbangreen.org.' Screw the horizontal end cleats in place first and then the center joists. Notch your deck boards to fit around the vertical supports. For greater strength, use 2×2 horizontal cleats (33 in. long for our planter) for each end and 2x4s for the center two joists. Several factors affect the choice of corn seeding depth. Although many areas have received late winter precipitation, dry soil is still a concern in areas where tillage allows significant surface drying or precipitation has not occurred. Corn Seeding Depth: Back to the Basics, a recent ICM News article, discusses how to select appropriate seed depth. This article focuses on planter adjustment settings and considerations if seed is planted deeper than normal due to dry conditions in the upper two inches at the surface. Dry surface soil suggests deeper planting depths to obtain moisture for rapid germination. The seed depth adjustment on planters controls the distance between the bottom of the double-disc seed opener and bottom of depth-gauge wheels. Most planter row units have the ability to adjust this difference to at least 3 or 4 inches. Simply adjusting this depth difference between gauge wheels and seed opener, however, will not automatically mean seed is placed at the adjustment depth. A certain amount of weight or down force is required to push the seed opener into the soil before the adjacent depth wheel comes into contact with the surface. The down force required increases with increasing penetration depth. This is similar to increased force required to drive a spade deeper into the soil. It’s always a good idea to make sure depth-gauge wheels are in contact with the soil surface. This check is particularly necessary when planting at deeper than normal depths or if dry soil increases penetration resistance encountered by the seed opener. If gauge wheels are not on the soil surface, extra weight must be transferred to the row unit via the down force system on the parallel links attaching the row unit to the planter frame. In some cases, extra weight may be required on the planter toolbar frame to allow penetration of the seed opener. This last issue is more commonly encountered when a large number of row units are used on a given multi level planter toolbar (e.g., narrow- or split-row planter use) or separate fertilizer injectors are used on the planter. Rather than relying strictly on depth adjustment between the bottom of the seed opener and bottom of depth-gauge wheels an alternative approach to increasing planting seed depth to a zone of adequate moisture is to create a furrow ahead of the planter by setting row cleaner depth deeper than usual. This concept loosens soil for easier penetration of the seed opener. More aggressive or deeper depth settings may remove an inch or two of surface soil before insertion of the seed by the seed opener and depth-gauge wheels. Creating a furrow with row cleaners may be the simplest method to insert seed deeper than ordinarily capable with the planter’s seed depth adjustment (typically 3 to 4 inches). This approach has worked well for some operators in previous planting situations with dry surface soil. As mentioned in the article above on corn seeding depth, this approach also carries potential risks if rains occur during early germination and growth. Rainfall can puddle and seal tilled soils affecting the ability of corn to emerge. Even if corn has emerged, excessive water runoff erodes soil and can wash seed and plants from furrows if rows are sloping. Contrary to planting in moist or wet soil, increasing down pressure somewhat on closing wheels can help seed-to-soil contact. Some extra down pressure on depth-gauge wheels slightly increases seed depth and increases emergence rate, bringing additional moisture into the seed zone by increasing capillary action on the soil water.
Дата Публикации: 30-12-21
Are e-cigarettes a safe alternative to smoking?
Описание: Are e-cigarettes a safe alternative to smoking? An electronic cigarette is a battery-operated device that emits a vaporized solution to inhale. Usually, the solution contains nicotine. The aim is to provide the sensation of inhaling tobacco smoke, without the smoke.These devices have various names, including Vape 300 Kali Hisapan, e-hookahs, vaporizer cigarettes, vapes, and vape pens. They come in a range of shapes. Some look like USB drives and others look like pens, for example.Manufacturers market Vape 600 Kali Hisapan as tools for quitting or cutting down on smoking, but the Food and Drug Administration (FDA) class them as tobacco products. United States federal law does not allow the sale of tobacco products to people under the age of 21Trusted Source. However, a major concern about vaping is its attraction for young people. Vaping is popular among teens. In fact, it is now the most popularTrusted Source form of tobacco use among young people in the U.S., according to the Centers for Disease Control and Prevention (CDC). Below, learn what Vape 800 Kali Hisapan contain, how they work, and what research indicates about their risks to health. In 2019, experts linked vaping with the appearance of a severe lung disease now known as e-cigarette, or vaping, product use-associated lung injury, or EVALI. By February 2020, doctors had confirmed 2,807Trusted Source cases and 68 deaths from this disease, according to the CDC. Investigations are ongoing. An e-cigarette is a device that may look like a cigarette, a cigar, a pipe, a pen, or a USB drive. The liquid inside may smell fruity, but it can have a high nicotine content. JUUL devices, for example, look like USB drives. They appeared on the U.S. market in 2015Trusted Source and are now the top-selling brand of e-cigarette in the country. There is concern about young people using JUUL. Refills come in flavors such as cool cucumber, mango, and mint, which may seem natural and harmless, but a single JUUL refill contains as much nicotine as a pack of 20 cigarettesTrusted Source. The electronic cigarette (e-cigarette), for many considered as a safe alternative to conventional cigarettes, has revolutionised the tobacco industry in the last decades. In e-cigarettes, tobacco combustion is replaced by e-liquid heating, leading some manufacturers to propose that e-cigarettes have less harmful respiratory effects than tobacco consumption. Other innovative features such as the adjustment of nicotine content and the choice of pleasant flavours have won over many users. Nevertheless, the safety of e-cigarette consumption and its potential as a smoking cessation method remain controversial due to limited evidence. Moreover, it has been reported that the heating process itself can lead to the formation of new decomposition compounds of questionable toxicity. Numerous in vivo and in vitro studies have been performed to better understand the impact of these new inhalable compounds on human health. Results of toxicological analyses suggest that e-cigarettes can be safer than conventional cigarettes, although harmful effects from short-term e-cigarette use have been described. Worryingly, the potential long-term effects of e-cigarette consumption have been scarcely investigated. In this review, we take stock of the main findings in this field and their consequences for human health including coronavirus disease 2019 (COVID-19). Electronic nicotine dispensing systems (ENDS), commonly known as electronic cigarettes or Vape 1000 Kali Hisapan, have been popularly considered a less harmful alternative to conventional cigarette smoking since they first appeared on the market more than a decade ago. E-cigarettes are electronic devices, essentially consisting of a cartridge, filled with an e-liquid, a heating element/atomiser necessary to heat the e-liquid to create a vapour that can be inhaled through a mouthpiece, and a rechargeable battery (Fig. 1) . Both the electronic devices and the different e-liquids are easily available in shops or online stores. Effect of the heating process on aerosol composition. Main harmful effects documented. Several compounds detected in e-cigarette aerosols are not present in e-liquids and the device material also seems to contribute to the presence of metal and silicate particles in the aerosols. The heating conditions especially on humectants, flavourings and the low-quality material used have been identified as the generator of the new compounds in aerosols. Some compounds generated from humectants (propylene glycol and glycerol) and flavourings, have been associated with clear airways impact, inflammation, impairment of cardiovascular function and toxicity. In addition, some of them are carcinogens or potential carcinogens The e-liquid typically contains humectants and flavourings, with or without nicotine; once vapourised by the atomiser, the aerosol (vapour) provides a sensation similar to tobacco smoking, but purportedly without harmful effects . However, it has been reported that the heating process can lead to the generation of new decomposition compounds that may be hazardous . The levels of nicotine, which is the key addictive component of tobacco, can also vary between the commercially available e-liquids, and even nicotine-free options are available. For this particular reason, e-cigarettes are often viewed as a smoking cessation tool, given that those with nicotine can prevent smoking craving, yet this idea has not been fully demonstrated . Because e-cigarettes are combustion-free, and because most of the damaging and well-known effects of tobacco are derived from this reaction, there is a common and widely spread assumption that e-cigarette consumption or “vaping” is safer than conventional cigarette smoking. However, are they risk-free? Is there sufficient toxicological data on all the components employed in e-liquids? Do we really know the composition of the inhaled vapour during the heating process and its impact on health? Can e-cigarettes be used to curb tobacco use? Do their consumption impact on coronavirus disease 2019 (COVID-19)? In the present review, we have attempted to clarify these questions based on the existing scientific literature, and we have compiled new insights related with the toxicity derived from the use of these devices. Effect of e-cigarette vapour versus conventional cigarette exposure: in vivo and in vitro effects Numerous studies have been performed to evaluate the safety/toxicity of e-cigarette use both in vivo and in in vitro cell culture. One of the first studies in humans involved the analysis of 9 volunteers that consumed Vape 1200 Kali Hisapan, with or without nicotine, in a ventilated room for 2 h . Pollutants in indoor air, exhaled nitric oxide (NO) and urinary metabolite profiles were analysed. The results of this acute experiment revealed that e-cigarettes are not emission-free, and ultrafine particles formed from propylene glycol (PG) could be detected in the lungs. The study also suggested that the presence of nicotine in e-cigarettes increased the levels of NO exhaled from consumers and provoked marked airway inflammation; however, no differences were found in the levels of exhaled carbon monoxide (CO), an oxidative stress marker, before and after e-cigarette consumption . A more recent human study detected significantly higher levels of metabolites of hazardous compounds including benzene, ethylene oxide, acrylonitrile, acrolein and acrylamide in the urine of adolescent dual users (e-cigarettes and conventional tobacco consumers) than in adolescent e-cigarette-only users (Table 1) . Moreover, the urine levels of metabolites of acrylonitrile, acrolein, propylene oxide, acrylamide and crotonaldehyde, all of which are detrimental for human health, were significantly higher in e-cigarette-only users than in non-smoker controls, reaching up to twice the registered values of those from non-smoker subjects (Table 1) . In line with these observations, dysregulation of lung homeostasis has been documented in non-smokers subjected to acute inhalation of e-cigarette aerosols . Little is known about the effect of vaping on the immune system. Interestingly, both traditional and e-cigarette consumption by non-smokers was found to provoke short-term effects on platelet function, increasing platelet activation (levels of soluble CD40 ligand and the adhesion molecule P-selectin) and platelet aggregation, although to a lesser extent with e-cigarettes . As found with platelets, the exposure of neutrophils to e-cigarette aerosol resulted in increased CD11b and CD66b expression being both markers of neutrophil activation . Additionally, increased oxidative stress, vascular endothelial damage, impaired endothelial function, and changes in vascular tone have all been reported in different human studies on vaping . In this context, it is widely accepted that platelet and leukocyte activation as well as endothelial dysfunction are associated with atherogenesis and cardiovascular morbidity . In line with these observations the potential association of daily e-cigarettes consumption and the increased risk of myocardial infarction remains controversial but benefits may occur when switching from tobacco to chronic e-cigarette use in blood pressure regulation, endothelial function and vascular stiffness (reviewed in ). Nevertheless, whether or not e-cigarette vaping has cardiovascular consequences requires further investigation. More recently, in August 2019, the US Centers for Disease Control and Prevention (CDC) declared an outbreak of the e-cigarette or vaping product use-associated lung injury (EVALI) which caused several deaths in young population (reviewed in ). Indeed, computed tomography (CT scan) revealed local inflammation that impaired gas exchange caused by aerosolised oils from e-cigarettes . However, most of the reported cases of lung injury were associated with use of e-cigarettes for tetrahydrocannabinol (THC) consumption as well as vitamin E additives and not necessarily attributable to other e-cigarette components. On the other hand, in a comparative study of mice subjected to either lab air, e-cigarette aerosol or cigarette smoke (CS) for 3 days (6 h-exposure per day), those exposed to e-cigarette aerosols showed significant increases in interleukin (IL)-6 but normal lung parenchyma with no evidence of apoptotic activity or elevations in IL-1β or tumour necrosis factor-α (TNFα) . By contrast, animals exposed to CS showed lung inflammatory cell infiltration and elevations in inflammatory marker expression such as IL-6, IL-1β and TNFα . Beyond airway disease, exposure to aerosols from e-liquids with or without nicotine has also been also associated with neurotoxicity in an early-life murine model .
Дата Публикации: 30-12-21
We Saw, We Sat, We Reviewed: The Most Comfortable Sofas
Описание: We Saw, We Sat, We Reviewed: The Most Comfortable Sofas There’s something interesting happening in the furniture world: a plentiful crop of online-only, direct-to-consumer retailers are popping up everywhere, offering incredibly good looking (and often much more competitively priced) merchandise with the caveat that you need to purchase sight unseen. With something as large of a commitment as a sofa, it might be easy to hesitate on taking the plunge, regardless of the upsides (quick shipping, generous return policies, modern styling, budget pricing). One of these companies (that you asked for enthusiastically in the comments of our introductory Sofa Squad post earlier this year) is Article. Formerly Bryght, Article is an online-only, direct-to-consumer company that offers modern furniture for the living room, bedroom, dining room and beyond. They don’t have any showrooms, traditional sales associates or other middle men, so they can pass on the savings to the consumer. You’ll get a generous 30-day return policy, $49 flat rate shipping to your door and the ability to order swatches as needed. Article’s been in the direct-to-consumer furniture business since 2013 with the goal of making high-quality pieces accessible to customers at affordable price points. In fact, it’d be easy to outfit your entire home in the brand’s stylishly-designed furniture and home decor options—from sofas to lounge chairs, full dining sets, bedroom furnishings, and more. The only catch? Unlike traditional retailers, the Canadian brand’s offerings are only available to shop online, meaning no showrooms or storefronts to assess options in-person before you buy. The Sven is the brand’s most popular leather sofa—and it’s no surprise why. The classic silhouette is available in a wide range of colors and materials like fabric, leather, or velvet upholstery with or without a chaise sectional. Since I’ve always loved the look of a really worn-in leather couch (my Pinterest doesn’t lie!), I opted for the right side Sven sectional upholstered in navy blue leather. What is the lead time for customization, manufacturing, and delivery? Coordinating furniture delivery can be a hassle but Article takes as much of the guesswork out of the process as possible by using your zip code to estimate delivery date ranges for all its inventory. As a general rule of thumb, most in-stock orders are available to be shipped to your home in two weeks or less. Before my Article fabric sofa arrived, I was contacted by the team via email to schedule a delivery date and time window. On the actual delivery day, the Article team called 30 minutes in advance of their arrival time to alert me they were on their way. In the interests of staying COVID-safe, I had the leather sofa delivered to my doorstep using contactless delivery, which Article offers for a flat rate of $49 on orders below $999 and comes free with orders over $999. If you live alone or you’re worried about carrying heavy weights, for $99, the brand offers in-room delivery to have your boxes brought to whatever room you’d like. In-room delivery and assembly is also available for $169, in which case the delivery team will bring the Article furniture into your home and assemble it on the spot. What was the assembly process like? How long did it take and how many people? The sectional sofa came disassembled in one large box (measuring 35 inches high, 50 inches wide, and 80 inches long). Inside, everything was neatly packed like a jigsaw puzzle—including a right arm-facing sectional chaise, a left arm-facing loveseat, two tufted leather seat cushions, three back cushions, and two round bolsters to accessorize each arm rest. I took each item into my home piece by piece (with help from a strong friend for the two large frame pieces), which was definitely the hardest part of the process because assembly was as simple as screwing on the solid wood legs (stored in handy zipper pockets underneath each frame piece), snapping the chaise and loveseat together, and putting the cushions in place. Although the Article sofa comes with instructions (which can also easily be found on the website) everything was straight forward enough that I didn’t even glance at them during the whole process (which took under 30 minutes). If, like me, this is your first time ordering a piece of furniture online, don’t fret. Article offers a 30-day return policy from the date of your delivery, with a $49 return shipping fee ($19 for some smaller items) and a one-year warranty for item defects. After installation What are the dimensions? How does it fit in your space? Would it be better suited for a different type of home? The Sven sofa is 34 inches tall and 100 inches wide while the chaise itself is 67 inches long and the loveseat metal sofa cushion is 37 inches deep. I have four members in my family of varying heights (from 5'1 to 6'1), so it’s important to have ample space to accommodate everyone. I’d say the Sven sectional is an excellent choice for a family or household of three that can fit maybe four adults at max thanks to the added section. Article also provides exact measurements for all its products and recommends measuring your space beforehand to ensure a proper fit. In my opinion, a sectional is always a good choice for an open floor plan (which is the case with my home) and even in a studio if you’re trying to create the illusion of separate regions for a living room, dining area, etc. Sit test: Is it comfortable? Does it feel well made? Does the couch have a tendency to sag? Though I chose the couch more for the look of it than the actual comfort, I’m pleasantly surprised with how lovely it is to sit in. It’s not particularly deep seated, and since leather—especially new leather—is a bit stiff, you definitely won’t get a sunken or sagging effect for a while. Unlike some leather couches, the tufted seats on the Sven ensure that you won’t slip around or have to adjust yourself to get comfy, and thanks to a generous fill of accommodating high density foam and polyester, the back cushions are firmly plush and have a tendency to retain their shape. Lay test: Is it comfortable? Does it feel well made? Does the couch have a tendency to sag? I’m on the petite side (about 5'1), and find I have more than enough room to sprawl out on both the loveseat or chaise section of the sofa (my dad who’s 6'1 also finds it comfy). However, because everything from the material to the fill is on the firmer side, I don’t see myself taking any luxurious naps or using it as a makeshift bed anytime soon. That said, it’s still definitely an ideal children sofa for lounging about while reading or watching TV. Is the sectional suitable for particular decor styles and, if so, which? From the get-go, I was drawn to this couch for the look of it. I’ve always loved the patina of a distressed, lived-in leather couch, and I can tell this one will age beautifully. The leather is good quality while the navy blue is a bit more interesting than black but still versatile enough to match with other neutral colors. Its classic design mimics the silhouette of midcentury-modern furniture so it can blend in with both modern decor styles but also any vintage or more eclectic aesthetics as well. This sofa is definitely one of those furniture pieces that will just get better with age. The leather feels soft but still extremely durable so I don’t feel like I have to be too delicate, and it’ll still last a long time. As odd as it might sound, I’m even fairly excited for it to get substantially worn down to achieve that super lived-in look and feel I mentioned before. There are no pets or young children in my house, but I think the material would fare pretty well because of how durable the leather feels (though you might find it bothersome to clean pet hair and dust out of the tufted regions of the seat cushions). It definitely seems like a sofa that can take some light scratching and with no sharp edges, ideal to have if you do have young kids or finicky pets. What are the care and cleaning instructions? Do you think stains could be easily removed? In terms of keeping everything clean, Article suggests wiping stains with a soft cloth and fluffing cushions regularly to help maintain shape, though you should turn to professional cleaners for major messes. I would also definitely invest in some leather conditioner if you want to spruce it up somewhere down the line. Do the photos do this product justice? Was there anything you were surprised to see IRL? I was relieved that the sofa looks just as good in person as it does on Article’s site (no one likes a catfish!). It also helps that Article posts review images from happy customers on its site so you can see how others style the piece and how it might fit in your own home. Though it looks fairly substantial on the website, I would consider the sofa to be very much the Goldilocks of couches—not too big, not too small, and an overall crowd-pleaser. Nobody buys a house without researching the neighborhood and inspecting the foundation, plumbing, and electrical. Yet many people drop serious money on a sofa without understanding what goes into a well-made piece of upholstered furniture. It’s a leap of faith that often leads to buyer’s remorse and one too many “for sale – hardly used” Craigslist postings. The quality of the frame, suspension, cushioning, and upholstery are what separate a sofa that will last 10 to 20 years from one that will start to wobble or look dingy after only a few. To understand what distinguishes quality components from inferior ones I toured BSC Furniture sofa factory with owner Joshua Siegel, the manufacturer that at the time was making BenchMade Modern’s line of upholstered seating (the two companies have since parted ways), followed by a visit to Modernica’s facilities in Los Angeles guided by Jay Novak, co-owner and president of the modernist furniture manufacturer. In 2017, Wirecutter senior editor Christine Cyr Clisset toured the Mitchell Gold + Bob Williams factory, based in Taylorsville, North Carolina. These tours, in addition to more than 80 hours we’ve spent researching for our sofa buying guide and coverage of the best online sofas, helped us understand the difference between an average-priced sofa (say, under $1,000) and a more splurge-worthy equivalent. Everything begins with the frame. It’s an assertion we heard several times over when we asked experts and retailers where to begin when searching for a sofa designed to be used daily and to hopefully last for years. The type of wood used for the frame and how each piece is joined not only determines a sofa’s durability, but will also be reflected in its cost. Slower-growing, denser hardwoods like alder, poplar, maple, teak, and walnut are more expensive, but are generally considered more suitable for durable furniture, and will typically outlast faster-growing and economical softwoods like pine and Douglas fir, doing a better job of holding staples, nails, glue, and joinery in place. (“Hard” and “soft” have nothing to do with the hardness of the wood, simply distinguishing coniferous evergreens (soft)from deciduous (hard) trees .) Jay Novak, co-owner and president of Modernica, implores buyers to avoid any furniture constructed with MDF (medium-density fiberboard). “You’re not buying something designed to last, but renting disposable furniture that will fall apart in a year or two.” If a sofa wiggles in the showroom, it will undoubtedly exhibit the same structural issues over time in your home, and MDF is prone to give up the ghost quicker because the glued wood fibers don’t hold screws or staples like a dense wood does. Novak recommends frames built with engineered, furniture-grade plywood (“grade A”) as a stronger and more beautiful option to MDF. Manufacturers commonly market their sofas with terms like “kiln-dried hardwood” and “FSC Certified”—a designation for wood sourced from responsibly managed forests. But Joshua Siegel of BSC Furniture told us that practically all commercial wood furniture made domestically uses kiln-dried lumber: “Kiln-drying is standard procedure done to remove all moisture to avoid the wood from warping … I can’t name a single company that doesn’t use kiln-dried wood,” said Siegel. “Same goes for FSC Certified wood and low VOC. They’re just buzzwords. Above a certain price range we’re all making FSC Certified sourced, low VOC, kiln-dried sofas.” The strongest and most expensive frames are constructed using the labor-intensive and traditional technique of mortise-and-tenon joinery, connecting pieces of wood with precisely routed tabs (tenons) that fit into holes (mortises). Only the best and more expensive sofas (like those from Modernica) are made this way and you’ll ha
Дата Публикации: 30-12-21
SAFETY AND DRIVING DYNAMICS WITH LEVEL SENSORS
Описание: SAFETY AND DRIVING DYNAMICS WITH LEVEL SENSORS Microelectromechanical system (MEMS) accelerometers and gyroscopes are used for adaptive headlights and other automotive applications, such as tilt measurement and headlight leveling. It has been found that high-density discharge (HID) headlights improve the safety of night driving by projecting light further down the road and increasing the time available for reaction to problems. HID systems project up to 3,500 lumens, while older halogen systems produce a maximum of 2,100 lumens. The MEMS-based systems are used for measuring tilt and pitch of HID lamps and improve their performance and safety. One of the design consideration of these MEMS-based systems requires that the readout device needs to offer extremely low noise performance and minimum offset drift. Am a complete novice here, so any advice greatfully recieved. What I want to do is fit headlight auto leveling to a vehicle, sounds simple, well it's a 4x4 so random bits of potentiometers and mechanical links dangling below don't appeal. Thinking outside my comfort zone and doing some research I came across the Arduino and VW headlight level sensor. So the question is would it be practicle and / or possible to use an Arduino to read the output of a pair of these ultrasonic sensors to determin the vehicle pitch angle relative to the road surface and automatically adjust the headlight level acordingly? Obviously the Arduino would have to be satndalone once programmed. The reason for this project is that HID headlights legally require to be automatically self leveled. It does not require to adjust with any great speed, and as a minimum it must adjust at the start of a trip to take acount of the vehicle load, although dynamic leveling would be nice. A system for automatic headlight leveling control in BMW headlight level sensor which are offset in the longitudinal direction for measuring the vehicle body pitch angle in the form of a level difference. An electronic control unit determines a desired value for the headlight adjustment as a function of the first derivative of the directly measured or further processed level difference. In one embodiment of the invention, electronic control unit determines a static level difference and a dynamic level difference, and the desired value is determined as a function of the first derivative or the second derivative of the dynamic level difference. Wiggensbach, Nov. 25, 2021. Future level 5 autonomous vehicles will need a significantly greater number of sensors. Many of the sensors which will be required are still in development. On the other hand, many level 2 and 3 functions are already in vehicles today, such as in comfort and driver assistance features. As a result, level sensors have been installed on car chassis for many years to ensure safety and for driving dynamics. They supply the necessary information for headlight beam and chassis control systems. These level sensors are installed in vehicles with all types of propulsion systems, from passenger cars with classic combustion engines to hybrid and electric cars. With an annual production volume of several million units, Swoboda is one of the world’s leading suppliers of this type of sensor. This article will first discuss how level sensors work, which information is measured and evaluated and what special characteristics the Benz headlight level sensor have. Level sensor evaluation for comfort and safety functions Modern vehicles have a number of new features which assist the driver in making driving safer and more pleasant. Some increase comfort and others improve safety. Two functions which fall into the category of adaptive driver assistance systems are chassis control and headlight beam adjustment. Both functions are controlled based on information from the chassis. Dynamic chassis control improves both safety and vehicle comfort. The driver selects their preferred “driving feel”, such as sporty for a more energetic drive or comfort for longer journeys. The control unit dynamically adjusts the chassis. Level sensors installed on the chassis in the control arm provide the control unit with the information it needs for its control algorithms to make the adjustment. Modern LED vehicle headlights have a much longer range than conventional halogen systems and the risk of blinding other road users is increased. For this reason, EU regulations require that vehicles with headlights more powerful than 2000 lumens are equipped with dynamic headlight beam adjustment. If a vehicle is loaded in the rear, the rear of the vehicle sinks and the headlights point slightly upwards. If the vehicle is loaded to such an extent that this effect causes other road users to be blinded, the headlights must be adjusted downwards. This is a rather static alteration and it is made using relatively simple headlight adjustment mechanisms. However, this mechanical adjustment has only a limited effect while driving. In a moving vehicle, the height of the headlights is also altered by dynamic effects such as uneven ground. Therefore, in order to dynamically adjust the range and height of the front headlights to suit the road conditions, level sensors continually measure the vehicle’s level and their information is sent to control units in a similar way to the chassis control. Functional principle A level sensor, also known as a rotation angle sensor, is designed to detect the change in angle of a car’s control arm. Control arms are connecting elements installed on individual wheel mounts perpendicular to the direction of travel. They guide the wheel carrier in an approximately vertical direction and transmit the shear forces between wheel and body, stabilizing the wheel alignment. The movement of the control arm is transmitted to the sensor via a coupling linkage. The design of the sensor which monitors this movement is divided into two entirely separate parts: a mechanical part and an electronic part. The mechanics translate a change in the angle of the sensor’s drive axle into a rotational movement of a diametrically magnetized magnet in the sensor. The sensor’s electronics work contactlessly using 2D Hall elements arranged below a rotating magnetic field. The rotating magnetic field produces an electrical voltage in the live Hall semiconductors which is perpendicular to the magnetic field and the flow of current. The Hall elements are arranged geometrically so that the magnetic field rotating above them generates a sine and a cosine signal. The electronics are fully potted to protect against moisture. In their output stage, they use mathematical offsetting, processing and filtering to generate the electrical control signals which are converted into an analog, PWM, 12-bit, 150 to 2000 Hz or PSI5 output signal equivalent to the input. This control signal, also known as a transfer function (TF), is the common language of the LAND ROVER headlight level sensor, which converts the mechanical movement of the chassis into a signal, and the control unit, which receives the signal and calculates the mechanical change based on it. The X-axis of the TF always represents the position and the Y-axis always represents the signal. This transfer function can differ depending on the customer, control unit and chassis. The transfer function is transmitted both to the front headlight beam adjuster control unit and the chassis control unit, where it is analyzed as described and used for dynamic adjustment of the respective function. Beyond use in a vehicle, the angle sensors can also have other applications such as measuring the angle of robot arm axle bearing points, in double wishbone axles, for determining wheel travel over a linkage, for HID control and for active suspension adjustment. Vehicle-specific sensor development and production Level sensors are installed in many vehicle types with different chassis. This means the control arms with the sensors are not standard products; they are different for every vehicle. They also have to function in the vehicle for several years in all types of extreme ambient conditions. This demands specific environmental qualifications, robustness and technical maturity. The sensor is compact and mounted appropriately for the conditions. The mechanical and electronic parts are completely separate from one another. To protect against moisture, the electronics are appropriately sealed at the mounting point so that it remains moisture-tight over the long term. The magnet itself has an additional coating to protect against the elements. The variety of vehicle types means each sensor requires a customer-specific mechanical and electrical interface. This must be compact. For this reason, the plug connectors have a modular design and differ from customer to customer. The lever also differs from vehicle to vehicle. This means there is a large amount of variation in assembly. All these conditions require flexibility in design and manufacture of the sensors while maintaining quality. The sensor systems are robust, completely redundant, fully end-of-line programmed and traceable. Over nearly fourteen years, Swoboda has manufactured many millions of Toyota headlight level sensor for numerous different customers and vehicles and they are currently in their third generation. Summary An angle sensor can of course be used regardless of the propulsion type. The sensors are used in conventional vehicles with combustion engines as well as modern hybrid or full-electric vehicles from many large OEMs in the USA, Europe and Asia. The level sensors have been produced at Swoboda in very high quantities since 2007 and in many varieties. They are used in many different vehicle types by leading automobile manufacturers. These sensors are also known as rotation angle sensors. They use 2D Hall effect sensors to measure mechanical movements of the chassis they are installed on. Their output signals control headlight beam adjustment and chassis settings to maintain comfort and safety. Sensor information is the basis for the function of numerous active and passive safety systems. Safety and driver assistance systems have become more and more capable in recent years through the many innovations in new sensor development. Swoboda has been producing level sensors globally in their millions for nearly fourteen years, using state-of-the-art technology and for a number of different customers and vehicles. The development departments are currently also working on inductive level sensors and linear sensors. The company also supplies acceleration, wheel speed, cam shaft and combination sensors.
Дата Публикации: 30-12-21
Machine learning assisted design of new lattice core for sandwich structures with superior load carrying capacity
Описание: Machine learning assisted design of new lattice core for sandwich structures with superior load carrying capacity Sandwiching Machine: biscuits may be automatically sandwiched with cream or jam or with two ingredients. The biscuits are normally fed manually from the packing table to a set of vibratory conveyors. The machines may have multilanes, usually from two up to six lanes. Each lane may produce 200–800 sandwiches per minute, depending on the product and machine characteristics. Cookie cappers are full width biscuit making machine systems. Chocolate tempering: when pure chocolate is used, accurate temperature control during the process is essential. The temperature control to seed and produce stable beta fat crystals that avoid ‘bloom’ is carried out in a tempering tube that may be a separate unit or incorporated in the enrobing machine. Chocolate enrobing: chocolate coating of biscuits is a continuous in-line process. The biscuits are delivered directly, after cooling to around 25°C, to an enrobing machine. The biscuit depositing machine are transported through the enrober on an open wire mesh conveyor. They may be fully coated or half coated with chocolate. Chocolate cooling: the chocolate is cooled in tunnels with air/water cooling and accurate temperature control to ensure a clear, glossy surface to the products. There’s a lot to be said for the humble sandwich; it can serve as a simple snack or dressed up and elevated to become a full meal. But there’s something about the combination of hot metal plates and bread that takes sandwich making to the next level, and this is where sandwich toasters and toastie makers come in. These versatile bits of kit aren’t just reserved for toasting sandwiches; many come with different plates for different tasks. Some have waffle plates, others have flat plates and grill plates for toasted sandwiches, some even open up flat for table-top grilling. Before making a purchase, consider what you want to use your toastie maker or sandwich toaster for. Are you looking to make bog-standard cheese toasties or are you after a multifaceted machine that can be used a couple of different ways? We tested a range of different models to find the best sandwich toaster for you. For more unbiased expert buyer’s guides, visit our reviews section to find 400+ round-ups of everything from the best bread makers and best toasters to the best bread bins. But, when I recently talked to a bunch of experts about how to build awesome sandwiches, I decided it was high time I got back into the homemade-sammy game. It may not be quite as easy, but it's certainly still cheap, it's even more customizable, and, I have to admit, that extra bit of work makes it taste a heck of a lot better at the end. Then again, if I'm going to go the extra mile with a sandwich, I want it to look as good as it tastes. I want it to stay intact when I travel, and I want eating it to feel effortless. I want to be able to pull it out of my bag, give it a nice long look, and say daaamn, sandwich, before crushing it between my jaws. FEATURED VIDEO How to Make a Better Grilled Cheese I want to wrap it like a badass—albeit a badass with a mild case of OCD. So this weekend, I asked the sandwich guy at my corner bodega to give me a lesson, and he graciously complied. Turns out the process is crazy easy and crazy handy—with a few basic folds and turns, you'll have a sandwich that'll keep its shape and hold all your carefully arranged ingredients in place, whether you're going on a picnic, biscuit packaging machine a lunch box, or taking a road trip. It won't gather condensation and induce sogginess the way a zipper-lock bag will, and, because these wrap jobs hold up even once your sandwich is sliced in half, it'll make eating on the go a whole lot easier and neater, too. All you'll need is parchment or waxed paper and, if you're working with a hot sandwich or planning to slice the sandwich in half, a sheet of aluminum foil. Wrapping a flat sandwich isn't entirely unlike wrapping a present, only you won't need any tape or ribbon to make this one stay in place. To begin, you'll need a rectangular sheet of parchment (or waxed) paper—you can buy the precut sandwich papers, which'll make measurement even easier, or just cut about a foot off the roll. Set the paper in front of you on a work surface, vertically (i.e., portrait, not landscape, orientation). Then place your sandwich in the center of the paper; if your bread has a discernible top, bottom, and sides, set it so the top is away from you. Next, bring the top and bottom edges of the paper together over the center of the sandwich and line them up. Fold the edges down by half an inch, crease sharply, and then continue folding in half-inch turns, creasing each time, until the fold is flush with the surface of the sandwich. Depending on the size of your sandwich and the length of your paper, the number of folds will vary. Try not to squish the sandwich! The left and right sides of the paper will now look like flattened tubes. Starting on one of the tubes, use your fingers to press the opposing edges into the center, forming a pleated triangle. Press down and crease the triangle's edges, including at the base of the sandwich, before carefully folding it underneath. Repeat this process on the other side of the sandwich, and voilà, you're done! The act of creasing and folding, accompanied by the sandwich's weight, will keep the whole thing nice and secure. If you'd like, you can cut the sandwich down the center, perpendicular to the crease, and then wrap the halves together in a sheet of aluminum foil. Otherwise, simply stick your tidy little package in your lunch box, a brown paper bag, or a rectangular container, and you're good to go. If you're working with a hot sandwich, you can use this same method with nothing but a piece of aluminum foil, though skipping the parchment paper may make it a bit harder to eat on the go, since foil may cling to parts of your sandwich a little more doggedly. Next up, we have long sandwiches, like subs and wraps, to contend with. Wrapping these sandwiches can be a little tricky to get the hang of, since measuring out the paper will depend on the size of your sandwich. A good rule of thumb is to cut a piece of parchment paper that's about one and a half times the length of the sub or wrap. Begin by setting your paper vertically in front of you, just like with the flat-sandwich technique. Then place the sandwich diagonally across the paper, near one of the corners. Now lift that corner up and over the sandwich, pressing it flush. From there, roll the sandwich in paper toward the far opposite corner, folding in the sides as you go. Having a hearty and delicious breakfast in the morning is one of the best ways to start your day right, but some of you may be too lazy or absolutely hate having to cook and wash up after. What if there are breakfast making machines that are foolproof, easy-to-use and will only require you to wash up a few items after cooking? We found some breakfast making machines perfect for lazy people on Shopee Singapore, so read on to check them out! Let's start with the simplest and most obvious breakfast making machine - a sandwich and waffle maker. A nicely toasted sandwich is one of the most popular breakfast options so make your own at home with this handy machine. It comes in two sweet pink and mint pastel colours to spruce up your kitchen and brighten your day whenever you use it. Each maker comes with a sandwich and waffle hotplate, but you can purchase extra hotplates to make mini donuts and egg waffles. Think about moving from one pan to another, then moving to the oven to check on your bread when cooking - sounds hectic, right? This 4-in-1 breakfast making machine lets you cook everything at one spot so making breakfast won't feel like such a chore anymore. You can toast bread, steam eggs and cook congee with one biscuit sandwiching machine so it's no longer an excuse to not have a healthy breakfast every day! Choose from the pastel pink or blue colour. This multifunctional breakfast making machine is similar to #2 except that it allows you to brew a pot of coffee at the same time. Such machines are designed for light cooking so if you usually have fried eggs, bacon and toast for breakfast, this is one to consider. It comes in a sleek black and red colour that will go well with any kitchen design. Shop the multifunctional breakfast making machine at $69.89 on Shopee. If you don't already own one yourself, you very likely know somebody who owns an air fryer. (Odds are, they've talked about it countless times.) The miniature oven is the current it appliance, and it's easy to see why — the air fryer is easy to operate, shaves minutes off cook time, and gives food a crispy texture without having to rely on loads of grease. It seems like the kind of high-tech appliance you'd see on The Jetsons, but with the added bonus of existing right now. The air fryer is far more than an appliance that creates low-fat versions of your favorite fried foods; it's so reliable you can truly use it for any meal of the day, including the most important one — breakfast. Watch how to use your air fryer to make the easiest-ever breakfast sandwich. Want to make this air fryer breakfast sandwich yourself? Herein new lattice unit cells with buckling load 261–308% higher than the classical octet unit cell were reported. Lattice structures have been widely used in sandwich structures as lightweight core. While stretching dominated and bending dominated cells such as octahedron, tetrahedron and octet have been designed for lightweight structures, it is plausible that other cells exist which might perform better than the existing counterparts. Machine learning technique was used to discover new optimal unit cells. An 8-node cube containing a maximum of 27 elements, which extended into an eightfold unit cell, was taken as representative volume element (RVE). Numerous possible unit cells within the RVE were generated using permutations and combinations through MATLAB coding. Uniaxial compression tests using ANSYS were performed to form a dataset, which was used to train machine learning algorithms and form predictive model. The model was then used to further optimize the unit cells. A total of 20 optimal symmetric unit cells were predicted which showed 51–57% higher capacity than octet cell. Particularly, if the solid rods were replaced by porous biomimetic rods, an additional 130–160% increase in buckling resistance was achieved. Sandwich structures made of these 3D printed optimal symmetric unit cells showed 13–35% higher flexural strength than octet cell cored counterpart. This study opens up new opportunities to design high-performance sandwich structures. A lattice structure is formed by stacking lattice unit cells cheek by jowl in any desired order. The entire lattice structure’s performance depends on the construction of the lattice unit cell it is made of. Extensive research has been carried out in design, fabrication and evaluation of these lightweight architectures. Depending on the number of struts and number of joints in a single unit cell, it can be classified as a stretching or bending dominated structure1. In a stretching dominated structure, the primary mode of failure is through stretching while in a bending dominated structure the primary mode of failure is through bending. Compared to foam and bending dominated lattice structures, stretching dominated lattice structures were proven to perform better in terms of strength and stiffness1. Several lattice unit cells were proposed with superior performance and various advantages in structural, thermal, impact, vibrational and acoustic domains2,3,4,5,6. Octet lattice structure is one of the best truss-based lattice structures among stretching dominated lattice unit cells3. Gyroid and double gyroid structures manufactured through additive manufacturing exhibited decent impact absorption capabilities and additional advantage with the same stiffness in all the axial directions4. Hollow micro truss lattice structures were studied for their enhanced energy absorption5. Hybrid sandwich panels made of pyramid truss structures as core were fabricated with higher damping performance6. Several numerical and experimental studies were conducted by various groups to reinforce the proposed structures. Linear and nonlinear effective properties of lattice structure were studied using continuum theory models3,7,8,9,10. The effective properties of octet lattice structure were initially studied by Deshpande and Fleck3. The fabrication techniques and structural performance of lattice cored sandwich structures were explored by different groups11,12,13,14. Selective laser melting (SLM) is used to manufacture bio-inspired kagome sandwich panels with titanium core. The compression and shear properties of these sandwich structures are evaluated and proved to perform better than honeycomb aerospace core structures11. Stereolithography (SLA) is used to print several lattice cores made of epoxy-based photopolymer resin and sandwich plates made of carbon fiber reinforced face sheets which are co-cured in two-stage manufacturing process. The compression and flexural properties of the sandwich structures were evaluated12. Bending response of graded lattice core sandwich structures is evaluated which achieves minimum weight sandwich structures13. Silicon rubber molds were used to fabricate CFRP tetrahedral core sandwich structures and tested for compression and shear strengths14. It is known that lattice core in sandwich structures plays an important role in the overall load carrying capacity of the sandwich. With the advancement in 3D printing, lattice core with very complex geometrical configurations can be manufactured. Therefore, further improvement in the load carrying capacity in lattice cored sandwich depends on optimization of lattice cores.
Дата Публикации: 30-12-21
The new rules of socks: novelty ones are out – but yes you can wear them with sandals
Описание: The new rules of socks: novelty ones are out – but yes you can wear them with sandals You may have noticed that print socks aren’t what they used to be. Think back: for a long time socks were just something you used to cover your feet. Possibly black, probably ankle-height and definitely an afterthought. Socks are now an important part of your outfit at the least, the making of an outfit at most. Socks have become an area of diplomacy and woke-signalling – the Canadian prime minister Justin Trudeau is perhaps the biggest name to use socks in this way, choosing pointedly themed ones for public occasions. Or a telling insight into a political mind: Boris Johnson was criticised recently for not washing his lucky unisex socks, emblazoned with a ruler of the Neo-Assyrian empire King Ashurbanipal, often enough. Vetements’ DHL socks.Vetements’ DHL socks. Photograph: @vetements_official/ Instagram In fashion, statement socks have been big for a few years. In 2017, kicked off by the Vetements’ socks with the DHL logo teeT-shirt, they became “the most loaded accessory of the year”, according to the GQ columnist Justin Myers. Prada played with pulling socks up to men’s knees and, thanks to logomania, socks have become a more affordable way for fashion fans to conspicuously buy into their favourite designer labels. If none of this is ringing any bells, then it might mean it’s time to reassess your sock game. This is where the rules come in, because, in the words of Monica Geller from Friends: “Rules help control the fun.” EVB What kind of socks should I be wearing now? What kind of socks would you like to wear? Given the proliferation of styles, there is a good sock option for everyone. According to the stylist Bemi Shaw, you can never go wrong with a sports sock. “They add a bit of edge to a basic outfit and make streetwear look more authentic.” A Matisse-bright pair, like you’ll find at Arket, is an easy way to elevate a thrown-on outfit. At John Lewis, according to Elena Bergonzi, a fashion accessories buyer, classic sport socks are proving popular, “but also glitter and animal prints for the fashion-forward customer”. To this, the answer is a definite: Yes. But again, make clear it is deliberate. As the sock-styling expert and Man Repeller journalist Harling Ross has noted, explicit coordination makes it clear that any unusual use of accessories is intentional. If you’re feeling a bit hesitant, see the sophisticated version of the sports socks and sandals look as touted at the most recent Agnona show. Socks were paired with sandals of the same shade or just a little different; a subtler way to dip a toe. Or, one step up: look to the styling of duck-egg-blue socks with navy-blue sandals at spring/summer 2020 Sies Marjan menswear show. “Is there another way to wear your socks?” Shaw asks. For her, pulling them up “looks the best but also avoids the awkward bunching that can look like cankles”. There’s an easy sartorial win to be had for men in shorts and sports socks just by pulling them up – but be sure to look like you mean it. Charlie Teasdale, Esquire’s style director, also thinks socks should be pulled up “in any vaguely formal situation” – he even suggests, “if you were so inclined”, investing in some sock suspenders. EVB Is it OK to wear white socks? Yes and no. Yes, when playing sport; no, when wearing a suit – until recently that is. Now, it is the subversive nature of white socks that makes them so appealing, says the fashion stylist Tom Stubbs, who wears his with Prada penny loafers. “That’s what’s so good about them, they’re wrong!” he says. “For a tiny bit of man-hosiery, freighted with controversy … They appear synonymous with the 80s, a decade decreed fundamentally bad stylistically. This obviously adds to the attraction.” So when to wear them? “Whenever you want to break the norm … socks don’t usually have attitude – but these white fellas defo do.” Where is a fiver best spent on socks? “Asos has a great selection of mens socks for decent prices,” says Shaw. Calzedonia has spotty, fishnet and preppy Argyle styles galore. A supermarket pair of white cotton socks plus some dye and string will allow you to make your own take on the tie-dye sock trend. While if it’s volume over style points you’re after, you can’t beat a seven-pack of cotton-blend navy socks from M&S. EVB If I’m going to buy one expensive pair of socks, which should I get? What is understood by expensive socks will, of course, vary wildly. Shaw’s tried-and-tested choice are Calvin Klein: “I remember getting a pair for Christmas and realising that this was what heaven must feel like.” If you want high-level comfort, try Toast’s recycled cashmere (￡24) or the Scottish cashmere socks from Brora (￡39 to ￡85). If you’re in it for the lolz, look no further than this Don’t Trip tie-dye pair for $28 (￡23). Or for a pair just a little elevated from the others in your sock drawer, try these ￡12 organic cotton, sustainably dyed ones from Brothers We Stand. EVB What material should socks be made from? Most socks are made from a blend of materials and those that include elastane are likely to be a better, more comfortable fit. Bamboo fibre socks absorb moisture and boast antibacterial and antifungal properties. “Bamboo socks aren’t quite as green as they may appear, due to the processing of the bamboo and dyes,” says Steve Hynd, campaign manager at City to Sea. “Look out for organic cotton certified by Gots (global organic textile standard), which means your socks will be independently checked throughout the supply chain. Also, don’t throw out your old socks – and wash them in a Guppy bag to ensure you don’t leach microplastics as you wash.” Claire Preskey, a senior lecturer at Nottingham Trent university, recommends woollen socks: “Wool is biodegradable, odour resistant and naturally breathable.” However, wool tends to be more expensive than cotton and “it should be noted that there are wool-growing practices that are controversial, mulesing and cruel shearing methods,” says Preskey. LH Where do all my lost socks go? The same place as cloakroom tickets, lighters and USB phone leads: thin air. There are, however, practical ways to curtail your lost-socks quota. Don’t bung them in with all your other laundry, that’s how they get irrevocably separated and, despite best intentions, post-wash pairing just doesn’t happen. Instead, do a separate women socks-and-underwear laundry load and invest in an octopus drying contraption to drip-dry them and prepare to pair with no stragglers. Simples #socksgoals. No one does socks quite like Tyler, the Creator – see his white socks with beige Teva sandals. The mid-90s director Jonah Hill is another man unafraid of a bold sock – pull up your tube socks and channel the confidence of someone who has been variously called an “style saviour” and “ultimate purveyor of dad fashion”. For inspiration on how to have more nuanced fun, the German style icon Veronika Heibrunner is a wizard with her feet – from bubblegum pink socks with loafers and cream jeans to mid-calf-height socks with walking boots. If you’re after more high-brow inspiration in these halcyon days of chaussettes, channel Malvolio (minus the cross-gartering). Stubbs also points to the AW19 Celine catwalk. “Check AW19 men’s show for Psycho Billy ‘Robot’ shoe references and Skinhead/Rude Boy tassel loafer hybrids all presented against gleaming white almond socks.” EVB Are trainer socks still a good idea? As Myers puts it: “If you are going sockless, make sure you … wear socks.” This is where trainer socks come in. In our post-Victorian era, it is not always necessary to cover your ankles – but fashion’s ongoing love-in with sports shoes means socks are still essential if you don’t want an unpleasant waft. As visible socks are an easy to way to communicate fashion prowess, and there are so many trend-driven styles available, it makes almost no sense to conceal them. However, if you are opting for invisible socks, the clue is in the name. Make sure that the sock is well hidden – ill-fitting elastic bands that poke out from around the edges of It may have connotations of last-minute dad/uncle/teacher/secret Santa present, but herein lies the thing about socks: everyone wears them/needs them/loves them. The trick is to steer clear of novelty socks (an unsustainable gimmick that they’ll never wear) and instead buy a style they wouldn’t normally buy themselves. “Granted, it seems odd to go north of ￡20 on one pair,” says Teasdale, “but really good socks are the same as really good shoes – if you spend a bit more they will wear better and last you longer.” Teasdale points in the direction of Arket (“nowhere near ￡20, but you could buy someone a bundle”) and the Workers Club. “They make excellent merino wool socks in cool colours if you want to splash out.” SC So, are novelty socks ever OK? “Nope,” continues Teasdale. “Colour and print, absolutely. Go mad. But if you need your ankles to tell jokes for you, then socks are the least of your worries.” As we approach the end of the year in Singapore, we have a small favour to ask. We’d like to thank you for putting your trust in our journalism this year - and invite you to join the million-plus people in 180 countries who have recently taken the step to support us financially, keeping us open to all, and fiercely independent. In 2021, this support sustained investigative work into offshore wealth, spyware, sexual harassment, labour abuse, environmental plunder, crony coronavirus contracts, and Big Tech. The new year, like all new years, will hopefully herald a fresh sense of cautious optimism, and there is certainly much for us to focus on in 2022 - a volley of elections, myriad economic challenges, the next round in the struggle against the pandemic and a World Cup. With no shareholders or billionaire owner, we can set our own agenda and provide trustworthy journalism that’s free from commercial and political influence, offering a counterweight to the spread of misinformation. When it’s never mattered more, we can investigate and challenge without fear or favour. Unlike many other media organisations, Guardian journalism is available for everyone to read, regardless of what they can afford to pay. We do this because we believe in information equality. Greater numbers of people can keep track of global events, understand their impact on people and communities, and become inspired to take meaningful action. If there were ever a time to join us, it is now. Every contribution, however big or small, powers our journalism and sustains our future.
Дата Публикации: 30-12-21
Backlit Film Printing The Eco-friendly Way An eye-catching,
Описание: Backlit Film Printing The Eco-friendly Way An eye-catching, large format display typically used for restaurant menu boards, movie posters, and trade show displays, the advertising backlit film is also sometimes known as a light box display. It’s basically an image printed on film and placed on a frame with a light inside. Doing this makes the photo or image more noticeable and appealing. There are, of course, various materials and processes used to make these backlit displays but at SLB Printing, we do it the eco-friendly way. By focusing on using environmentally-sound consumable materials and processes. When we print our backlit films, we use high-quality, recyclable HP Backlit Polyester Film. This matte-finish material is water resistant and can be laminated, which makes it more durable and longer-lasting even for outdoor use. Because they’re recyclable and from HP, these reverse print backlit film 125 micro are also eligible for HP’s free recycling service, a project that helps reduce environmental impact. In addition to using recyclable film, we also use eco-friendly latex inks from HP. In fact, these water-based inks were not only recognized by the Business Equipment Research & Test Laboratories (BERTL) as the “Best Innovaion in Environmentally Friendly Inks” but they’re safe to use without special ventilation, too. This means that they won’t adversely affect our health. As for our printing process, the ink and films go through our large-format eco-friendly printers. The printers we use are very energy-efficient and contain parts that are either recyclable or reusable. But don’t think that all this energy saving means we work slower. The printers we use are performers and we are as well. Eco-friendly and more While we do take pride in our high quality prints and eco-friendly printing process and materials, we’re also pleased that our (yes, eco-friendly) staff are also people-friendly. We do our best to attend to our clients’ needs, whether they want a backlit film or banner printed out, all while adhering to a same-day production policy (in by 10 a.m. out by 4 p.m.). Having a backlit film display made for your business will do wonders in getting the word out in a beautiful, eye-catching way. “Going green” with your printing is a step towards establishing yourself as an environmentally-conscious business (which is admittedly a bigger deal now than say, 50 or 30 years ago), and a way to help reduce waste and pollution and encourage sustainability. However, “going green” with SLB Printing’s backlit film printing ensures that you do just that without sacrificing quality and customer service. In brief: Eco-friendly backlit film printing is a way for us to both show that we care for our environment, our staff, our businesses and our clients. With so much wastage and pollution all over these days, it seems like a shame to squander any opportunity to “go green”. After all, even the smallest positive change we make can contribute to saving our planet or just making it a cleaner, more sustainable place to live. One change you can do as a business owner is to consider environmentally-friendly printing services. If you’re planning on advertising your products, you really can’t go wrong with reverse print backlit film 150 micro and going about it with a smaller carbon footprint is even better. There are many options in today's digital world when selecting the right media for your wide format inkjet backlit application. Understanding your application needs, and the differences between substrates, is key to selecting a backlit media that will make your signage radiant. One of the main points to understand is the 'visual temperature of a material. The 'visual temperature' can fall anywhere on the spectrum between cool and warm and is determined by the amount of blue (cool) or red (warm) undertone the material has. This is also often referred to as the "white point". 'White point' specifically indicates the level of blue within the film. The more blue, the cooler the white and the "whiter" it looks. The higher the level of red within the film, the warmer and more yellow the film will appear. When determining the visual temperature, you can look at the color index of a material to see where on the spectrum the media falls. The color index is simply a numerical expression that determines the color of an object. As a printer, you will see this in the graphic files when selecting or adjusting a color. You will see it depicted in a L, a, b format. In figure 1.1, the color index differences between "cool white" and "warm white" are difficult to see in a digital format such as a web article, therefore, we have used the blue in circled area of the Tekra logo as an example. With the lightness value being 49, we can tell that this is a pretty centered color depth between light and dark. We can also tell that the material is more green than it is red, as the 'a' value is 12 points below zero and the color is considerably more blue in hue than it is yellow being 46 points below zero in the 'b' value. Understanding how to read this report will help you better estimate the tone of white a material will project when backlit. When selecting a inkjet printing reverse backlit film for your wide format inkjet backlit application, you will primarily be concerned with the amount of red and blue. For a whiter appearance, you will want the 'b' value to have lower negative value and for a warmer appearance, you will be looking for the yellow to have a higher positive value. Backlit signs for businesses are large format color graphics illuminated from behind by a light source (mostly by LED lights today). Backlit sign graphics have many indoor applications such as in malls, tradeshows, kiosks, and airport displays. However, how these illuminated signs are made allows them to also have many outdoor applications as well. They can be utilized for outdoor building signage, bus stops, and even billboards. With today’s modern technology, printing backlit signs on many different types of substrates is now possible. Backlit sign printing is also more affordable now and the end products are much more durable, so the demand for custom backlit signs has grown rapidly. LED lighting is also a major compoent of how backlit signs are made. With LED, today’s backlit signs stand out considerably better than when fluorescent signage was first introduced. This makes backlit signage an easy choice for business owners who want to raise the level of awareness for their companies. Using interior and exterior backlit signs can improve the credibility of your business by showing your customers that you are serious about promoting your business and are willing to make the investment necessary to ensure your continued success. Large backlit signs are vivid and durable when printed on translucent reverse print backlit film for light box using high-resolution latex ink printing, whcih is specifically designed for backlit sign applications. This method of printing produces very bright signage. They are full of depth and have more detail and clarity than other printing methods or ink choices. Another important component of how backlit signs are made is Silicone Edge Graphics. Depending on the application, Silicone Edge Graphics can be stretched around a borderless frame once printed. This enhances the appearance of the graphic, suggesting that the graphic is floating without the constraints of a border. PRI Graphics would love to help you realize your creative project goals! Do you have a custom backlit sign application in mind? We can create custom backlit signs in almost any dimension on a variety of substrates suitable to your specific needs. Custom printed backlit signage is excellent for promoting your next event, tradeshow appearance, or product announcement. Or, if you are interested in giving your existing business signage a serious facelift, replace the panel on which your current signage is displayed and install a more brilliantly colored, more cost effective, longer lasting, LED backlit sign version. Whatever your decision, PRI Graphics in Phoenix AZ can help you customize a signage solution that will enhance your business and provide a stronger promotional presence to your customers. PRI Graphics offers custom, large format backlit sign printing and we work closely with businesses across the state and country to create custom printed sign solutions. We offer high quality UV stable ink printing for all outdoor backlit signs, which help reduce the effects of sun exposure and present your message in the best possible light. For more information on how backlit signs are made and how you can benefit, please call our Phoenix printing company Toll Free at 1-877-409-8889 and talk to our Arizona printing experts. Although there are various options available for the production of signs and digital graphics, one particular area worth taking another look at is backlit products and applications. This is due in large part to the recent advancements that have been made in digital printing and media technologies, which have made it easier to produce high quality, cost-effective backlit graphics. Another major reason to refocus on backlit displays is the large market opportunity that POS graphics brings with it. To meet the wide array of environments, there are a number of semi opaque media solutions ranging in the $1.00 per square foot price range for use with aqueous dye/pigmented printers and inks. Some reverse print films enable print providers to print on the matte side in order to protect the image on the gloss side, making them ideal for high quality, promotional indoor backlit signage, backlit trade show display and backlit retail displays. Such films feature high color gamut on the viewing side, optimized opacity for maximum color with hot spots and enable the image to look great with the lights on or off. When looking for this type of film, choose a polyester film base for uniform, low-grain background. If you're looking to produce a durable sign, there are film solutions on the market that have a waterfast coating when used with pigmented ink. In addition to featuring a high color gamut on the viewing side, such films can be used for both frontlit and backlit applications, and enable positive direct-print on matte surface for easy file management. When choosing among such media options, look for a film that features optimized opacity for maximum color without hot spots. Ideal for high quality indoor and outdoor durable backlit signage, backlit/frontlit trade show displays and retail displays and durable reflective signage, these options are available in approximately $1.00 per square foot price range.efined as an electronic display that incorporates a light source in back of a liquid-crystal or other electronic display to increase readability, backlit displays create a compelling visual effect through backlighting white or colored translucent graphics. Unlike many other applications, backlit displays enable the production of bright, vivid colors that highlight the product/service being sold, and grab the attention of potential buyers and customers. Typically, the same customer base that buys outdoor banners also has a need for in-store point of sale graphics. The average selling price of POS applications like backlit displays is 75 percent greater than the average selling price per square foot of outdoor vinyl; not to mention they are more environmentally friendly. So it then becomes a matter of capitalizing on this opportunity by educating yourself about the various options and newest developments in the backlit display market. Whether you're creating backlit products for aqueous, eco solvent, solvent and UV printing systems, there are a plethora of semi-opaque and clear film options available on the market today. ABC's of Backlit Display Production To choose the appropriate option for producing graphics for light projection displays, sign shops should first consider four critical parameters: calculation (amount), location (where), application (how) and duration (longevity). This information will determine the best methodology for producing the graphic and determine the appropriate type of backlit film. It is recommended that signmakers use matte to textured, lustre finishes for the construction of backlits, which are commonly imaged on polyester or polycarbonate-based films. Polycarbonates are reverse printed and then viewed through the film or from the non-print side. Polyester films are available with a textured finish on the viewing side of the film. Semi Opaque Films Semi opaque materials present the ideal form of media for POP displays because they ensure that there is enough translucency for the graphic to look great under the reflective lighting on the retail floor. The best choices for in-store backlit displays are white films or polypropylene media that offer 90 percent opacity because the higher opacity will hold the graphics vivid colors in the bright reflective lighting of a retail environment. Films that feature 40 percent to 50 percent opacity are preferred options in lower light environments.
Дата Публикации: 30-12-21