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- Создано: 18-11-21
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Effects of melting parameters and quartz purity on silica glass crucible produced by arc method
Описание: Effects of melting parameters and quartz purity on silica glass crucible produced by arc method We have investigated the effect of hydroxyl (OH) content in fused silica crucible on the scintillation and optical properties of the CsI single crystal, but not limited to, grown by Bridgman technique. For the purpose, 0.1 mol% Tl doped CsI single crystals were grown in crucibles made from fused silica of different grades with OH content varying from 20 ppm to 200 ppm. Silica glass of crucibles was characterized by FTIR and UV–VIS-NIR spectroscopy for the estimation of OH content. Grown crystals were tested for their scintillation performance and a correlation between OH content in silica glass and crystal quality is established. The possibility of ‘OH’ out-diffusion from silica crucible into the melt at higher temperature was further established by temperature dependent study of outgassing from silica crucible by residual gas analyzer (RGA). Further, an optimized process for silica crucible annealing to remove OH (
Дата Публикации: 18-11-21
Solar street lighting is a unique opportunity for sustainable recovery
Описание: Solar street lighting is a unique opportunity for sustainable recovery In response to the economic fallout from COVID-19, the European Union has formulated a major recovery plan for the continent with a key focus on adapting to the digital age and investing in cleaner and more resilient technologies for the future. In the U.S., the 2021 American Jobs Plan aims to steer $2 trillion into productivity and long-term growth, including a strong focus on building resilient and climate-friendly infrastructure. With economic and climate resilience plans taking a more concrete shape across the globe, Signify believes that solutions such as solar lighting pave the way for countries to build back better. According to Allied Market Research the global market solar energy was $52.5 billion in 2018 and is set to grow to $223.3 billion by 2026, vastly accelerating the scale of renewables. One of the fastest growing solar street light. "Solar street lighting technology has come on leaps and bounds in recent years and is fully aligned with the goals of EU and U.S clean energy and economic stimulus initiatives. Just 15 streetlights can save enough electricity to power a home for a year," said Harry Verhaar, global head of government and public affairs at Signify. "Being a digital technology, it can be connected to sensors and be controlled remotely, enabling forward-thinking municipalities to leapfrog to solar and reap the benefits of the digital age." President Joe Biden’s administration already has proposed $621 billion of additional investment in transportation infrastructure, with $20 billion earmarked to improve road safety and $174 billion for electric vehicles. A sizeable chunk of the latter would be spent on grant and incentive programs to build a national network of 500,000 electric vehicle charging stations by 2030. Signify advocates specifically for the wide adoption of solar and all in one solar street light which will not only help improve road safety, but also pave the way to lower emissions and eliminate the need for extra power stations to power the street lamps. This is particularly useful in more remote areas where existing infrastructure is minimal. With the strain taken off power stations, excess capacity could be diverted towards supporting charging stations for electric vehicles. Greek experience Solar is the ideal technology for serving far-flung communities with intermittent power supply or coverage. For example, in 2020, Signify installed solar streetlights on the Greek island of Leipsoi in areas lacking full electricity coverage including a playground, allowing the community to feel safer. A total of 28 autonomous Philips SunStay luminaires were used, each combining a solar panel, an LED light, a charge controller and a battery in one housing unit. The lights also contained an infrared motion sensor which detects movement and alters brightness accordingly, increasing energy efficiency and minimizing light pollution. "As we have many hours of sunshine throughout the year this is a very effective and functional solution for those areas on our island that are not connected to the power grid," said Fotis Mangos, mayor of Leipsoi. "The lights have such an aesthetic design that they seamlessly blend in with our island’s natural landscape." The electricity grid doesn’t always follow the street layout on the island and the solar installation allowed for an inexpensive, unobtrusive and environmentally friendly way to light roads and pathways without needing to dig trenches for electrical cables. "Solar lighting is a key part of our commitment to sustainability and to climate action, as we aim to help people move to cleaner technologies," said Signify’s country leader for Greece, Polydefkis Loukopoulos. "The expansion of solar lighting in new areas of Greece strengthens our vision to provide local communities with the security that results from high-quality solar lighting." With the addition of hybrid technologies, solar lighting is a feasible solution in areas with only seasonal sunshine, allowing countries at higher latitudes to access its benefits. This technology broadens the market for solar power. A version of solar is available beyond sun-soaked countries to around 6.5 billion people in the world. According to Antonio Espada, head of public segment in Europe for Signify, solar panel street light is the best of both worlds. It uses sunlight to charge its batteries and on cloudy days seamlessly switches to electricity from the grid. It’s highly energy efficient and increases the use of renewables and balances electricity loads. The battery power can be used during peak hours so fewer power stations are required. "Solar and solar hybrid power streetlights are particularly well suited to countries and regions where power outages are common. It can help deter crime and contributes to safer, more resilient communities," added Verhaar. Ultimately, solar lighting is an accessible, efficient and future-proof solution for community development, and one which could hugely benefit global recovery on both sides of the Atlantic. Discover more on how lighting can help to meet Green Deal targets. This paper examines the gap between the design and in-situ performance of solar streetlight interventions in two humanitarian settings. Displaced settlements often lack street lighting and electricity. Given that off-grid solar streetlights produce surplus energy, we hypothesized that this energy could be made available for daily usage, to improve system performance and provide further energy access to displaced populations. We recognize, however, that solar streetlight performance and longevity have typically been poor in remote and refugee settings. Eleven solar streetlights were fitted with ground-level sockets and their performance monitored, in two displaced settlements: a refugee camp in Rwanda and an internally displaced population settlement in Nepal. Considerable performance gaps were found across all eleven systems. Inefficient lights and mismatching system components were major issues at both sites, reducing targeted designed performance ratios by 33% and 53% on average in Rwanda and Nepal, respectively. The challenges of deploying these types of systems in temporary settlements are outlined and a number of suggestions are made to guide future developments in the design and implementation of sustainable solar streetlight interventions. Today's solar street LED lights are able to provide reliable, quality lighting both in developing and developed countries, thereby reducing light poverty and the economic and environmental costs of electric outdoor lighting. Rapid technical innovation and dramatic price reduction in the LED, PV module, and battery components, which has occurred in the last 5 years, will accelerate the penetration of solar street LED lights across the world. Applications will not be limited to countries with significant insolation only but will extend to Northern regions as well. This study provides a critical overview of a technology that will play an important role en route to global sustainability. For further resources related to this article, please visit the WIREs website. In 2016, on the northern shore of Lake Victoria, Jinja City sat in darkness. The city, the second-largest in Uganda, had run up an overdue power bill of 1.3 billion Ugandan shillings ($3.5 million), so Umeme, the nation’s largest energy distributor, disconnected the city’s street lights. Even before Umeme cut the power, most roads in this city of 870,000 near the source of the White Nile lacked illumination: Only the colonial-era center of town was equipped with solar garden light, and many of these had begun to sputter out due to age and poor maintenance. Districts that had grown as unplanned areas on the outskirts before being incorporated into the city had never been lit at all. “The area in the city that is planned is quite small,” says Kennedy Kibedi, a social media marketing specialist who works in tourism in Jinja City. “On the fringes of the city, in the suburbs, there’s a lot of informal development.” That pattern holds true for many of Africa’s largest cities. As places like Nairobi, Lagos, and Kampala have grown, they’ve absorbed informal settlements that aren’t connected to national power grids. As a result, street lighting is scarce, scattered and unreliable, and the costs for installing conventional grid-based lighting are high. So Jinja City administrators looked to neighboring Kampala, the nation’s capital and its largest city, for an alternative solution: solar-powered street lights, powered not by the grid but by photovoltaic panels and batteries that are either attached to each light pole or housed at a mini power station to support a group of lights. The Kampala Capital City Authority began revamping that city’s street lighting with solar-powered equipment in 2014, when just 115 kilometers of 1,200 kilometers of roads in Kampala had street lights, and only a fraction of those were operational. By 2016, when Jinja City was grappling with its power cut, the success of Kampala’s program was already apparent. Reports published that year show that the new solar spot light had reduced energy usage and costs, decreased traffic fatalities and accidents, and helped foster a more vibrant night economy in the capital city.
Дата Публикации: 18-11-21
On the Move: Unpacking the Challenges and Opportunities of Electric Vehicles
Описание: On the Move: Unpacking the Challenges and Opportunities of Electric Vehicles SINGAPORE - More than 600 electric vehicle (EV) chargers will be installed at some 200 public carparks in HDB estates, industrial estates and the Central Business District over the next 12 months. The first of these car chargers are expected to be installed by the end of this year. By the third quarter of next year, there will be 210 charging points in the central region, 50 in the north, 100 in the north-east, 120 in the east and 140 in the west. The Urban Redevelopment Authority (URA) and the Land Transport Authority (LTA) said on Friday (Sept 3) that a consortium comprising ComfortDelGro Engineering and Engie South East Asia has been awarded a tender to set up EV charging points in selected carparks in the central, east and west regions. Another consortium comprising Primech A&P, Charge+, Sunseap Group and Oyika has been awarded a tender to install the charging infrastructure in carparks in the north and north-east regions. The tenders, which form a pilot tender put out in November last year, are the first steps towards a national target of 40,000 charging points in public carparks by 2030. URA and LTA said they wanted to ensure that the pilot tender for the charging points was awarded to operators with quality charging services, financially sustainable business models and competitive charging prices. "As such, agencies adopted a price-quality method to assess and select proposals that would provide the best value for both consumers and the authorities," said URA and LTA. They said the consortiums led by ComfortDelGro and Primech A&P have offered competitive charging rates and a sustainable business model. URA and LTA added that these two consortiums have also committed to delivering a complete suite of services, including the installation, operation and maintenance of EV charging infrastructure, among other proposals. They said the consortium will pay the Government concession fees ranging between $0.108/kWh and $0.154/kWh for the right to deploy charging points. ComfortDelGro and Engie said in a joint statement on Friday that they won the tender to install 479 of the 632 metal car charger in the pilot roll-out. They said the chargers installed by them will comprise 192 22kW AC chargers, 279 7kW AC chargers and 8 50kW DC chargers. Transport Minister S. Iswaran said in a speech at the Land Transport Industry Day on Friday that the building up of an EV charging network is a key component of Singapore's strategy to promote electric vehicles. He noted that land transport currently accounts for 15 per cent of Singapore's domestic carbon emissions, with more than 90 per cent of this coming from the vehicle population. Mr Iswaran said the Transport Ministry and LTA have been working on the design of the market structure for EV charging in public residential carparks, and for the necessary upgrades to the electrical infrastructure. A request-for-information exercise conducted by LTA earlier this year collected feedback from 27 respondents. Mr Iswaran said these inputs will be considered by the Government in shaping the policy for EV charging infrastructure. He also announced on Friday that LTA and public transport operators will seek to generate more solar power from the public transport infrastructure. LTA will launch a tender to deploy more solar photovoltaic systems, likely via a leasing mode, said Mr Iswaran. Such systems use cells to convert sunlight into electricity. "A notable feature of the tender is that it will seek creative technologies and installation methods to optimise yield at less conventional areas, such as covered linkways and pedestrian overhead bridges," said Mr Iswaran. Mr Iswaran, who was speaking to an audience made up of people across the land transport industry, also said that Covid-19 has continued to affect the sector. He said rail and bus commuter ridership remain at just over 60 per cent of the levels before the pandemic started. Taxis and private-hire car trips are at around 75 per cent of usual levels. Mr Iswaran noted that transport workers have been at the forefront of the fight against Covid-19. “Our transport workers have kept our world moving through the darkest days of the pandemic,” he said. Electric vehicles have the potential to reshape the transportation sector in the United States, drastically cutting carbon emissions and clearing the way for significant climate progress. Transportation is the highest-emitting sector in the country, producing 28 percent of all carbon (CO2) emissions in 2018. Electric cars could transform this high-emissions sector. A study released by the Union of Concerned Scientists in 2015 shows that, in the United States, electric cars generate half or less than half of the emissions of comparable gasoline-powered cars from manufacturing to disposal. California Governor Gavin Newsom recently underscored the importance of electric vehicles when he announced on September 23 that California would require all new cars and passenger trucks sold in the state to be zero-emission vehicles by 2035. Though electric vehicles (EVs) still emit carbon emissions through the manufacturing process and from the fossil fuels used to generate the electricity they need to recharge, their enhanced energy efficiency secures significant emission reductions. On average, EVs convert over 77 percent of the electrical energy from the grid to power at the wheels, while gasoline vehicles only convert between 12 to 30 percent of the energy stored in gasoline to power at the wheels. Nevertheless, there remain significant hurdles to widespread adoption of electric vehicles, which are explored below in part 1. Congress is considering legislation that would address these hurdles, including the Electric Vehicle Freedom Act, and has already passed the Charging Helps Agencies Realize General Efficiencies (CHARGE) Act (see part 2 of this article). Part 1: Electric Vehicle Challenges and Opportunities Charging times. There are three major “levels” of plastic shell car charger available for EVs. The standard 120-volt plug, often used for home appliances, charges slowly but can fill a battery to near full capacity with several nights’ charge, or about 20 to 40 hours. The 240-volt "level two” chargers generally provide 20 to 25 miles of charge in an hour, which shortens charging time to eight hours or less. In homes, level two chargers can use the same outlet type required for clothes dryers or electric ovens. In the EV industry, the connectors used for level two charging are known as SAE J1772. Finally, "level 3" direct current (DC) fast chargers can charge a battery up to 80 percent in 30 minutes. Currently, level two chargers are the most widely available—the Department of Energy lists 22,816 public stations in the United States. There are important cost differences between charger types. According to a study by the Rocky Mountain Institute, costs for a level two charger’s components range from $2,500 to $7,210 and from $20,000 to $35,800 for a DC fast charger. The decision of which stations to install requires balancing the cost of installation with the needs and convenience of drivers. Charger compatibility. Level two charger development has been a relatively coordinated process, with all automakers besides Tesla using the same charge port model (with Tesla drivers using an adapter to connect). Three different varieties of DC fast chargers are used by different auto manufacturers: the SAE Combined Charging System (CCS), used by most manufacturers; CHAdeMO, used by Nissan and Mitsubishi; and the wireless charger (only available to Tesla drivers). This lack of vehicle compatibility differs from universal vehicle access to gas stations and could be an obstacle to widespread electric car adoption. Availability of charging infrastructure. Rather than being refueled at a typical gas station, electric vehicles must be charged at electrical outlets in order to run. Many EV owners charge their cars at home in their garage using a special wall-mounted car wireless charger. This arrangement works for most people, because the average person drives 29 miles per day. This distance is well within the range of today’s electric vehicles, most of which can travel between 150 and 250 miles on a charge, depending on the model. However, two major difficulties arise. First, for drivers who live in apartments, parking garages are rarely equipped with charging infrastructure, and installing such infrastructure may be cost prohibitive for building managers. There is also the additional problem of the electric costs incurred at common outlets. Because regular EV charging consumes more energy than most other residential uses, building managers need a mechanism to monitor EV charging to ensure the driver of each vehicle pays for their own electricity usage. Second, expanded charging infrastructure is needed for EVs to make long-distance trips that require multiple stops for charging. A recent study by the International Council on Clean Transportation indicated that 10,000 more charging stations will be required to support EVs traveling on inter-city corridors by 2025, based on trends of increasing EV ownership. When it comes to longer trips, EV owners can experience “range anxiety,” the fear that the car will run out of power before reaching a suitable charging station. Surveys show that concerns about range and charging availability are an important limit on consumer uptake of EVs. A 2018 report by the Harris polling firm found that 58 percent of respondents named “running out of power” as their top reason for not purchasing an EV, and 49 percent named “low availability of charging stations.” Renewable energy and climate mitigation. While not a hurdle to widespread EV adoption in and of itself, the electrical grid’s continued reliance on fossil fuels can reduce the cost-effectiveness of EV adoption as an emissions abatement strategy. Despite reducing emissions even when connected to a fossil-powered grid, electric vehicles are a much more cost-effective emission reduction tool when renewable energy sources make up a greater proportion of the energy mix. According to the Intergovernmental Panel on Climate Change (IPCC), on a relatively high-carbon grid (which produces 500–600 grams of CO2 equivalent emissions per kilowatt-hour of power generation), light-duty electric vehicles can cost “many hundreds of dollars” per ton of CO2 abated. However, in a relatively low-carbon grid (which emits below 200 grams of CO2 equivalent per kilowatt-hour), EVs cost below $200 per ton of abatement. Maximizing the use of renewable energy to power electric vehicles is therefore crucial. Grid capacity. Trading out a national fleet of gasoline-powered cars and trucks for a fleet of EVs means that millions of people will depend on the electric grid in new ways. Therefore, power generation capacity will need to increase to accommodate these vehicles without straining the grid. Expert assessments vary on how much electricity demand will increase with widespread EV use. The Department of Energy predicts a 38 percent increase in electricity consumption by 2050, mostly due to a high penetration of electric vehicles. Researchers at the Energy Institute at the University of Texas Austin conducted a state-by-state assessment of a scenario in which all personal cars, trucks, and SUVs are converted to plug-in electric models. The study finds that state energy consumption would range from an increase of 17 percent in Wyoming to 55 percent in Maine. Most states’ consumption increases clustered between 20 to 30 percent. While some state grids have the available excess capacity to generate increased amounts of power with existing infrastructure under favorable assumptions for charging times, others do not. The ability of grids to handle EV charging also depends on what time of day the vehicles are plugged in. EVs have a much lower chance of overloading grids if charged at off-peak hours, when fewer consumers are using electricity.
Дата Публикации: 18-11-21
Rising Prices for PE, PVC; Others Flat to Down
Описание: Rising Prices for PE, PVC; Others Flat to Down The trajectory of prices of the five volume commodity PVC resin powder was upward through September; but starting last month, a reversal was underway for most of these resins, possibly excepting PE and PVC. Factors in the continued flat-to-downward trajectory for PP, PS and PET included expectations of improved supply availability, lower feedstock prices, slowed seasonal demand, and loss of export opportunities due to higher prices. Factors maintaining strong pricing for PE and PVC, at least in the short term, included strong demand and tight monomer and polymer supplies brought on by planned and unplanned production shutdowns. These are the views of purchasing consultants from calcium carbide method pvc resin, Inc. (RTi), senior editors from PetroChemWire (PCW), and CEO Michael Greenberg of The Plastics Exchange. Polyethylene prices moved up 5￠/lb in September, capping the fourth consecutive month of price hikes, bringing the total to an unprecedented 19￠/lb. Suppliers also came out with a fifth increase—another 5￠/lb—for October, owing primarily to continued strong demand and tight supplies, made tighter following precautionary shutdowns for Hurricane Laura in late August. Mike Burns, RTi’s v.p. of PE markets, held that PE prices would stay firm, with the October hike—if not implemented right away—hanging over discussions with customers for the remainder of the year, due to sustained demand and tight inventories. PCW’s senior editor David Barry said he would not be surprised if suppliers stuck to their increases, but expected processors would have better leverage this month and in December in the negotiation of 2021 contracts. With the exception of HDPE blow molding grades, where a real shortage occurred, processors were able to get what they needed, but went through it faster than anticipated, noted Burns. PE Price Trends November 2020 Both Burns and Barry ventured that a slow recovery of tight suspension method pvc resin inventories was already underway at the start of the fourth quarter, which ought to help ease price pressure in first quarter of 2021. Going into October, The Plastic Exchange’s Greenberg reported that while demand for spot PE had been good, processors generally opted for just single truckloads, and a whisper of uncertainty had crept into the market. “The fourth quarter often brings softer demand and could provide the market an opportunity to rebalance especially when downed plants return fully online and new reactors begin production,” he commented. PP Prices Up, Then Flat to Down Polypropylene prices moved up 3￠/lb in September, despite stability in propylene monomer contract prices, which remained at August’s 36￠/lb level. Moreover, PP suppliers announced another 3￠/lb “profit-margin increase” for October, a move that looked to be at least partially successful due to tight supply and some rebound in domestic demand, according to Scott Newell, RTi’s v.p. of PP markets, as well as PCW’s Barry, and The Plastic Exchange’s Greenberg. All three saw the recent upward trajectory halting, if not reversing. Newell ventured that suppliers’ attempted margin expansions in September and October would erode between mid-month and December. “Suppliers have had leverage all this time owing to unplanned and planned monomer and PP outages, and low capacity utilization overall (around 83%). But the longer buyers can wait to order for 2021, the better. I expect quite a few pounds of PP and monomer capacity to be brought on stream in that time frame.” PCW’s Barry reported that while suppliers were seeking to boost their margins further in October, there were already signs that high PP prices were crimping demand for price-sensitive products such as PP tubs and totes, which depend heavily on “big-box” retail channels. He cited factors such as slower demand, rising PP imports and improving operating rates in the fourth quarter that could bring a turnabout in the PP supply situation in late November into December. Reporting that spot PP demand was strong, supply was scarce, and prices were holding steady, Greenberg noted, “Our outlook has been moving from bullish back towards neutral as we feel there is some froth in spot pricing; still, industry inventories are at a historically low level and need to be rebuilt from a deep trough.” PS Prices Flat to Down Polystyrene prices were flat in September and expected to be flat in October, with downward pricing pressure mounting this month. After July/August hikes totaled 5￠/lb, Robin Chesshier, RTi’s v.p. of PE, PS and nylon 6 markets, predicted that lower prices are in the offing, perhaps dipping 1-3￠/lb before year’s end. Chesshier cited poor domestic demand, which never rebounded after the 12￠/lb decrease in April/May, along with falling prices of feedstocks. PCW’s Barry reported that PS prime market prices were stable going into October with the trajectory a bit unclear. He ventured that the market could hold steady through fourth quarter based on the lack of significant feedstock cost pressures. The implied styrene cost based on a 30/70 ratio of spot ethylene/benzene was at 19.75￠/lb, down slightly from 21.1￠/lb at September’s end. Spot PS prices were mostly steady. He also noted that continued demand for styrene monomer exports could support a price hike for PS before year’s end, but slow seasonal domestic demand for PS would work against such a move. PVC Prices Up PVC tabs in September moved up by 5￠/lb, the result of an initial 3￠ hike increase and a 5￠ hike announced later in the same month. Suppliers also issued a 4￠/lb October increase, though both PCW senior editor Donna Todd and Mark Kallman, RTi’s v.p. of PVC and engineering pvc paste resin, doubted its full implementation. Still, these sources anticipated that the remaining 3￠ of the second September increase would eventually take hold. “I think the 4￠/lb price hike might be a stretch. Still, suppliers have leverage,” said Kallman. He cited a very tight market, a robust increase in demand from construction, significantly higher export prices, much lower availability, and the late-settling September ethylene contract price increase of 3.5￠/lb, which added 1.6￠/lb to the cost of producing PVC. Kallman expected that November would see significant recovery in PVC supply, and prices could be flat for the remainder of the year. PCW’s Todd reported that PVC production remained problematic for three of the four main suppliers, with Shintech the only one operating at full rates at the start of October. Westlake’s Lake Charles, La., site had regained electricity following a Hurricane Laura outage, but market watchers thought it would take the entire month for the company to build enough PVC inventory to rescind its force majeure declaration. Formosa cited unexpected difficulties at its Point Comfort, Texas, plant that interfered with production of its specialty PVC. Formosa declared force majeure in early October, and also cited an upcoming government-mandated 30-day shutdown of the plant in the near future. Oxy was allocating resin to its customers, due to feedstock production difficulties at Pasadena, Texas. PET Prices Down PET monthly contract business started October at 45-48￠/lb for railcars delivered U.S. Midwest and South—steady from early September. Prices were expected to fall 2￠ to 5￠ this month as overall demand for PET bottles and containers sags during the colder weather, according to PCW senior editor Xavier Cronin. At the same time, demand for PET bottles and containers related to the COVID-19 pandemic remains strong. This is due to purchases of bottled water and carbonated soft drinks at retail outlets and by governments and non-profit agencies for emergency use and other needs, like supplying water to essential workers. Prices of PE and PP moved up in double-digits, while those of PS, PVC and PET were also on an upward trajectory, in the first six weeks of this year. The remainder of the first quarter was projected to continue on this track, owing to global constraints on feedstocks and some resins, coupled by continued strong demand in most cases. Those are the views of purchasing consultants from plasticizer, senior editors from PetroChemWire (PCW,), and CEO Michael Greenberg of The Plastics Exchange. Polyethylene prices rose 6￠/lb following the December 5￠ increase, and suppliers announced a 7￠ increase for February, according to Mike Burns, RTi’s vp of PE markets, PCW senior editor David Barry, and The Plastic Exchange’s Michael Greenberg. Said Burns, “Prices are now 30￠/lb higher than they were in December 2019, without any significant cost increases to produce polyethylene.” These sources anticipated that the past month’s 7￠ increase had strong potential of being implemented, attributing the increases to tight inventories that have resulted from both planned and unplanned shutdowns and strong domestic and export demand, particularly to Latin America and Mexico. Supply is especially tight for HPDE and LDPE, due to the outage of Braskem Idesa’s large Mexican plant, explained Barry. While the plant was back up and running at 15% of capacity, it was unlikely to make a difference in the supply shortage until April. Meanwhile, prices of spot PE were at prime material levels. Burns predicted that demand will be strong through the first quarter and perhaps into second quarter, while supply will remain tight; and he did not expect much price relief till the second half of the year. PCW’s Barry noted that some processors who had bought heavily during December and January were positioned to cut back on orders last month and perhaps into this one. Spot availability was limited in the domestic resale market, and most offers were being quoted with the 7￠/lb February increase and a rollback provision. Going into the second week of February, Greenberg characterized spot resin trading as hyperactive. “Processors, many on supply allocation, have flocked to the spot market as they scramble to procure material. This has resulted in very high volumes of resin changing hands through our trading desk and buyers’ resilience continued to astonish even as prices spiraled ever upward.” He noted that spot gains so far this year were 11￠ to 19￠/lb, depending on scarcity of the grade. PP Prices Climb Farther Polypropylene prices moved up 12￠/lb in January, in step with propylene monomer, which settled at 60.5￠/lb. Yet another double-digit increase was expected for the monomer last month, along with a 6￠/lb margin increase sought by PP suppliers, according to Scott Newell, RTi’s vp of PP markets and PCW’s Barry. Newell expected that suppliers would succeed with the margin increase. Barry also reported that LyondellBasell issued a 6￠/lb hike for March, in addition to any change in the monomer. Newell, Barry and Greenberg all noted that these increases are primarily feedstock driven. Newell ventured that the monomer tightness would continue, as inventories had yet to be rebuilt following several outages in the last half of 2020. Despite very strong current PP demand, all three sources expected demand destruction to follow, though it has not occured to the degree originally thought. “We’re seeing increasing imports of propylene, PP pellets and finished goods like BOPP film,” Newell said. “Imported PP is priced better than domestic resin, even with the higher freight costs.” Barry noted that the spread between U.S. and Asian market pricing was approaching 40￠/lb.
Дата Публикации: 18-11-21
A review of a machine design of chocolate extrusion based co-rotating twin screw extruder
Описание: A review of a machine design of chocolate extrusion based co-rotating twin screw extruder Based on innovation and competitive market for food industry, there are several food products which have been designed to attract customer. Since there is USD 39,431 millions of chocolate sales in 2018, USA , chocolate product shapes have been developed based on manufacturing process. This paper presents a review process of a cocoa machine design of chocolate extrusion based co-rotating twin screw extruder. A property of suitable chocolate for extruder was established. The pros and cons of machine extruder for food processing including, a screw extruder design were exposed. Since there were problems in the chocolate extruder, the process parameters such as barrel temperatures, feed rate, screw speed, motor load and melt pressure were established. These parameters would be applied to design screw extruder for chocolate processing. Demand is growing for higher-quality chocolate, alongside more sustainable manufacturing processes. But current chocolate production faces problems keeping up. The different production stages rely on their own specific cocoa equipment, components can be difficult to clean and potentially harmful metal particles can be released into finished products. EU support helped the BAT project optimise the chocolate manufacturing process with a versatile ‘one-stop shop’ machine which, as well as being easy to clean, avoids the need for producers to run a set of expensive, bulky and energy-intensive machines. There are typically around seven stages to chocolate manufacturing involving three to five dedicated machines. First, beans are toasted before husking to remove the shell surrounding beans. The resulting cocoa goes through a pre-refiner before passing through a refiner to create a smoother consistency. Next, the ingredients enter a separator which ensures no grains are too large before going through a further refining stage. The last stage is conching in which the acidity of the cocoa is removed. The BAT solution combines the pre-refining, refining and conching stages into a single step, reducing the number of machines needed for the process to a single machine. Importantly, the machinery is designed to be easy to clean and does not release metal into the product. Crucially, it can also refine both products containing water (mix hydrated) and those without anhydrous, something that is not possible with current technology. The icing on the cake is that it comes at a comparatively low purchase price. The team built a prototype BAT refining head, to carry out tests. “The refining head is the processing step on which our innovation is based. We had a number of challenges to overcome with these tests, such as keeping temperature and quality constant across the whole product batch. Despite the complexity we managed to solve these with our design,” says Stefano Marello, project coordinator. Opportunities for smaller businesses The chocolate and cocoa market is a fast-evolving market. According to recent research, the demand for chocolate in Europe is predicted to grow by a compound annual growth rate of 3 %, between 2018 and 2022. While Europe is the world’s largest producer, the bulk of this production rests with six big multinationals. Additionally, despite advances in food production, cocoa is still one of the products that goes through a high number of stages prior to consumption. The quality of the finished product is dependent on the multiple steps and the quality of the treatment it undergoes. The BAT system offers chocolate manufacturers a more effective solution as they refine their products in the pursuit of higher quality. Importantly, it also opens up opportunities for producers to produce chocolate directly from the bean, while avoiding the cost associated with multiple cocoa processing machine. “BAT controls the temperature of the core of the product much better than current technologies throughout the refining cycle. This makes it possible to produce different chocolates from the same cocoa beans. This could lead to an increase in the quality of finished products on the market, as well as new opportunities for smaller businesses, as the barriers to entry are reduced,” says Marello. The team are currently pursuing further funding opportunities in order to develop an industrial-scale prototype, capable of running 24 hours a day. A lot of time has passed since the first refiner conches were built to make chocolate. At that stage all necessary processing steps were done in the same chocolate tempering machine, which sometimes took a week to get the final product. This paper is not intended to summarise all the technical developments since then as such information is available in textbooks1. Instead it aims to briefly introduce the different systems for chocolate mass production offered by various companies in order to give readers an overview on what is currently available on the market. Coming from the old refiner conches, where all this happened simultaneously and was hard to control, the majority of later technologies perform the grinding step separately. Only few mill types are able to handle chocolate preparations, as it is initially a very sticky mass, which can transform to a sticky powder during milling, when specific surface of particles increases. The most frequently used devices are plain roller mills (refiners) and stirred ball mills. Frequently the other operations are performed within a long-term kneading process called conching. Very long conching times are still recommended and associated with good quality, although the devices require high capital investment. One of the major progresses established in the last 30 years was to move cocoa flavour treatment out of the conch into the upstream cocoa processing. Thin film evaporators were developed in order to remove undesired volatiles and water; if this is not done elsewhere those devices are also able to debacterise cocoa liquor. Unfortunately the very popular Petzomat is not built any more, but alternatives from other companies are available. Nowadays chocolate producers can strongly reduce conching times if they insist on using pre-treated cocoa liquor of high flavour quality. Untreated cocoa is also still used, which then requires extra conching, like in former times. Similar principles are followed for milk chocolates by developing milk powder pre-treatment procedures. For example it was proposed to dry skimmed milk powder to below one per cent water and to coat it with fat, which allows us to perform a very short liquefaction process instead of classical conching2. Crumb is an ingredient made by drying milk together with sugar and cocoa liquor. Originally this was done for preservation of the milk, but nowadays it is performed in order to create the strong caramel flavour preferred in some countries. For downstream mass production the same technologies can be used, as with other chocolate types. If cocoa butter is replaced by another fat, the product is usually called compound and not chocolate. Technologically most compounds are close to chocolate mass and similar equipment can be used to make it. The largest difference is rather an economical one, as very expensive cocoa butter is replaced by relatively inexpensive alternative fats. After some initial information on chocolate mass properties the systems available on the market will be introduced. For that purpose information was obtained from various manufacturers, followed by questions and discussions on aspects such as: Is it possible to produce dark, milk and white mass using identical equipment or even on the same production line? What are the main advantages of the process for larger and also for smaller chocolate producers and what is the minimum size of an industrial production line? How much energy does the process require? What is the approximate capital investment necessary for a production line? Of course not all questions could be answered. In particular the last point, as process equipment is usually designed individually by chocolate tempering equipment manufacturers for their clients. So in practice, chocolate makers will always have to negotiate individually with suppliers. This paper will provide an introduction to the possibilities on the market. Chocolate mass properties Physically, chocolate mass is a suspension of particles in a continuous phase of liquid fat. Downstream when producing final products for the consumer, fat crystallisation is initiated and the mass is forced into the desired shape and solidifies. These steps are not considered here, although many properties of the final product can be predicted by measurable properties of the still liquid chocolate mass. Therefore flow properties are usually measured at a temperature of 40°C, which is close to the temperature that chocolate melts in our mouths. So texture sensations like a smooth melt or a sticky behaviour are usually correlated to flow properties. As chocolate mass is a non-Newtonian fluid we have to measure its shear stress at different shear rates, which results in a flow curve. Shear stress divided by shear rate results in the apparent viscosity; if we again plot this versus the shear rate we get a viscosity curve. Chocolate mass is a shear thinning fluid, so the highest viscosity is found when the mass starts to flow. Interaction between particles is considered to be responsible for this behaviour3, which is very different to Newtonian fluids such as water. So one important part of the flow curve is at very low shear. The yield value defines the shear stress, when the mass starts to move. As a minimum shear rate is necessary for the measurement, usually the yield value has to be extrapolated from the flow curve according to model equations, like the ones developed by Casson and Windhab1. Yield values or measurements at low shear stress also have a great practical importance, as many industrial operations are carried out with masses flowing slowly, for example the equal distribution of still liquid mass in a mould. On the other hand side some processing is done under high shear, e.g. when pumping or spraying masses. This is best described by the other end of the flow curve. So usually it is extrapolated to infinite shear, the result is then called Casson or Windhab infinite viscosity. Naturally, fat content, emulsifiers and ingredient properties have the largest influence on viscosity. After those, particle size distribution and particle package density are also important. Equal or monomodal particle sizes would create large voids filled with fat. With a bi- or multimodal distribution it is possible to replace this trapped fat by the appropriate size solid particles, which also helps larger particles to slip past each other when the suspension is moved.
Дата Публикации: 18-11-21
Why Hot Foil Stamping Helps Packaging To Shine
Описание: Why Hot Foil Stamping Helps Packaging To Shine Differentiation. It’s what every brand owner wants for their product, but in increasingly crowded markets, it is becoming harder and harder to achieve. Brand owners know that packaging is the key differentiator on the shelf, and special finishing techniques – such hot foil stamping and thermal embossing – can elevate their product compared to others, and provide consumers with a visual shortcut to the quality of what’s inside. Hot foil stamping is the process of using heat and pressure to apply metallic foil or holograms to materials such as light papers, carton board, laminated board, plastics and corrugated board. “In a world where we have very mature markets with limited opportunity for major growth, there is no question that products need to differentiate themselves somehow,” said Jacques Reymond, head of product marketing Business Unit Sheet-fed at BOBST. “Hot foil stamping helps to reinforce the value to the product and is often associated with premium products. Ultimately, the box is a marketing instrument, and by using hot foil stamping, you can convey the quality of what it inside.” The term can encompass simple flat foil stamping, deep embossing or embossing combined with foil stamping, hologram and holographic foil application and foil stamping combined with micro & structural embossing. Traditionally, gold or silver are the most common colors used for foiling, but a wide range of colored foils are available. Application across industries Hot foil stamping is used across a wide range of industry sectors, but most notably in food and drink (particularly confectionary such as premium chocolate, wine and liquor bottles, and other premium foods), cosmetics, electronics, banknotes, business cards, greeting cards and art work. There is no doubt about the value of embellishments like cold stamping foil. According to a study by the Foil & Specialty Effects Association (FSEA), hot foil stamping and other similar enhancements on product packaging can help attract consumer attention faster and keep attention longer than ordinary packaging. In another study of disposable single-serve coffee packaging, the packaging with gold foil attracted the study participants’ attention 2.5 times faster than the control packaging. It’s not just about looking good. Hot foil stamping is also used for its anti-counterfeiting properties, particularly in pharmaceuticals, and in technology such as smart phones. The stamp of sustainability Sustainability is becoming an even bigger priority for brand owners and is in itself a means of differentiation. Many assume that packaging with foil is not recyclable and therefore not sustainable, but a study by the FSEA on the recyclability and re-pulpability of foil-decorated stock and board validated the recyclability of paper products decorated by the traditional hot stamp foil processes. In addition, the study found that neither hot nor cold foil-decorated products would give rise to problems that may render the decorated paper products unsuitable for recycling. How is hot foil stamping evolving? Hot foil stamping has been around in one form or another for well over 100 years. The process itself has not changed dramatically in that time, but the technology is evolving and enabling better efficiency for manufacturers. A hot foil stamper may be an offline, stand-alone machine, or may be in line with a printing press and/or other units. While mainly sheet-fed, some high-speed hot foil stampers are web-fed. Whether sheet or web-fed, sophisticated handling systems are needed to position the substrate and foil between the plate or cylinder that holds the dies and that supplying the counter pressure. “These machines have seen some remarkable advances in recent years,” said Jacques Reymond. “For example, normally, hot stamping foil for paper requires several passes through the machine – the printing, then the enhancement, then the cutting. That’s a lot of movement on the sheet registration. But BOBST integrated a power register in MASTERFOIL 106 PR that overcame that. We are always looking to evolve.” Reymond is referring to POWER REGISTER 2, which delivers perfect foil-to-print register in MASTERFOIL 106 PR, a hot foil stamper from BOBST associated with the highest quality. It is also packed with clever features like lower beam cam movement, which allows for longer impressions and higher foiling quality, or a foil unwind system that makes changing foils as easy as pressing a button. BOBST: The hot foil stamping pioneers With more than fifty years of experience in the design and manufacture of foil stamping machines, BOBST has constantly been at the forefront of advances in this technology. From the BOBST SP 1260 BM of the 1960s, through to today’s highly sophisticated equipment, flat bed BOBST presses have pushed forward the boundaries of the hot stamping foil for plastic process. “With over fifty years’ experience in the hot foil stamping market, and several thousand installations worldwide, BOBST is a pioneer in the area,” said Jacques Reymond. “We are well known for providing equipment that is long lasting, and made for high productivity, precision and quality. And we never get complacent; we are always moving forward, always looking to the future to find new ways to improve productivity for our customers.” Conclusion While hot foil stamping isn’t the only form of differentiation for packaging – cold foil, varnishes and metal inks are just three examples of other great visual embellishments – it is a steadily growing sector that is here to stay. Simply put, the effect will always appeal on packaging and provide a visual shortcut to the quality of the product inside. Foil stamping can be tricky business, and certain types of inks, stocks, and stamping surfaces can add to the challenge. . This article contains a sampling of information contained in the guide as it relates specifically to difficult-to-stamp surfaces, as well as additional information on the subject gathered by InsideFinishing. What common signs indicate that the ink is not dry enough for foil stamping? What are the suggested solutions? If the ink on the printed sheet does not have time to properly dry and an operator begins to foil stamp, many times the foil product itself will begin to smear when a finger is passed along the print area. If an operator can see ink from the sheet appear on the polyester film carrier after the image has been stamped, that is another sign of a sheet that is not completely dry. In addition, when the ink offsets onto the sheet below on the feed table or on the feed table rollers, it is a sure-fire sign that the ink is not ready for foil stamping application. The solution when working with wet ink is to simply allow the proper drying time before stamping. If these problems are occurring, the operator should double check with the printer that wax-free inks were used on the job. If the inks were not wax-free, or if rubber-based inks were used, the job will be very difficult or impossible to stamp over the litho. To assist with helping the sheets dry faster, reduce the pile height to smaller stacks and allow air to flow through the pile. If there is little or no time to allow the sheets to dry on their own, they can be sent through a dryer of some type, such as a UV tunnel. Remember that black and dark blue are two of the most difficult inks to dry. Also, if a great deal of black coverage exists, it is recommended that the black be printed with one or two colors. Try to stay away from process black – this will take much longer to dry. What problems can occur with foil stamping over UV coatings or varnishes? What can be done to work with these problems on press? The most common side effect of trying to foil stamp on a UV surface is a shark-tooth appearance at the edges of the foil stamped image. The main reason this occurs is a coated surface with less than the required dyne level to accept the foil. UV also causes problems when silicone is added to the UV. This, too, can cause a shark-tooth appearance on the foil stamped image. If there is a significant amount of silicone in the coating, then there is very little you can do to get the foil to adhere to this surface. The silicone will create a slick surface and simply not allow the foil to adhere. However, if the cause of the coating problem is the lack of a proper dyne level, there are several possible solutions. First, the operator should check the dyne level by utilizing a set of dyne pens that measures the surface tension of the sheet. To foil stamp or glue, the dyne level must be at least 38 and even a bit higher for a good quality stamp. If the dyne level is not at 38 or higher, one solution is to corona treat the sheets through an off-line corona treatment system. The corona treatment will change the molecular make up of the coating on the sheet and raise the dyne level to a proper level for stamping. Another solution is to texture the foil stamping die or the substrate. This can be accomplished by asking the die supplier to sandblast the stamping die before it is shipped. The operator also can place a piece of sandpaper on the make ready board with the grit facing the die, make several impressions without the foil product, move the sandpaper into a new position, followed by several more impressions. This will create a sandblasted effect on the die. The texturing of the die will help relieve trapped air on the sheet surface and should allow the foil to adhere without trapping air. Remember that texturing the die will dull the foil and create a satin look even with a bright metallic foil. There are other steps that can be taken to help relieve trapped air on the coated surface. Dome the makeready to allow any gas or trapped air that has built up between the coating and the die to escape more easily from the center and flow to the edges of the foil stamped image. Also, make sure that the operator is utilizing a foil product that is formulated for UV surfaces or surfaces with lower dyne levels. This will help ensure a higher quality stamp, especially if the dyne level is hovering around the 38 level or a little below. Last, satin foils seem to perform better on UV or varnished surfaces. Consider going with a satin gold if the customer will allow it. What precautions should be taken when applying foil over foil? Often when an application includes foil stamping one foil over another foil, the operator is apt to be lax in his concern on press, taking for granted that all hot stamping foils are easily overstampable. This is simply not the case. If the foil is beginning to pick or uneven coverage is occurring on the second pass of foil, it is a clear sign that there is a problem. Specific hot stamping foils are manufactured to be overstampable, but some formulations are not. It is very important to check this before beginning a job where one foil will be applied over another. However, this may not be the only reason for a potential application challenge. If the first foil stamping pass was stamped with too much impression strength or a soft makeready board, this will leave a deep groove around the image and the operator may have problems with coverage on the second pass. It’s possible that a visible indented line will show where the second pass of foil stamps over the top of the first. This can be prevented by using a hard makeready board such as epoxy glass board. This will allow the first foil to be applied with less pressure, keeping the first pass from being stamped too far into the stock. Another problem can occur with overstamping if the first pass was applied at a temperature that is too low. If this occurs, it can leave a residual wax release coat on the surface of the image area. This will make the second foil pass adhesion very difficult. It is recommended that the operator run the first pass of foil at a fairly high temperature, higher than usual, to make sure that the wax release coat is completely removed, creating a more suitable stamping surface for the final stamped image. Foil stamping on plastic sheeting continues to be a popular application. What are some of the precautions that should be taken when hot stamping foil for label plastic on a plastic surface? As with difficult-to-stamp coatings, the first steps when foil stamping on plastic are making sure that the plastic has been properly treated and has a dyne level above 38. Without pre-treating the plastic sheet first, the problems with ‘shark toothing’ or pin-holes will occur when trying to stamp. Just as there are a variety of foils for various types of paper stock, there are specific adhesive formulations for plastic. The foil stamper needs to check with its foil supplier and order a foil product specifically formulated for plastics – a graphics foil will not be a good choice for these applications. Because plastic can cause more problems with gassing or air entrapment than most paper stocks, utilizing a cylinder-style machine to apply the foil is a good option, if available. Applying the foil through a cylinder foil stamping machine will allow the foil to be laid across the plastic sheet. This stamping action differs from the vertical platen style machines that press the hot stamping die directly into the substrate, thereby trapping air. Another advantage with the cylinder-style machines is that the rolling action also can help keep the plastic from overheating and melting during the foil stamping process. Utilizing a hard make ready, such as epoxy glass board, is a good choice for plastic sheets. This will help to keep the die from penetrating too far into the sheet, which can leave an outline on the back of the sheet. In addition, a domed makeready is recommended to help squeeze out any air or gasses that might be trapped between the die and the sheet. This is especially important with a larger flat stamp image area.
Дата Публикации: 18-11-21
Sandblasting
Описание: Sandblasting Air-abrasion (sandblasting) techniques have long been employed in restorative dentistry to enhance the mechanical adhesion between metals and adhesive resins. Sandblasting uses a high-speed stream of aluminum oxide particles propelled by compressed air to remove unfavorable oxides and contaminants, increase surface energy, bonding surface area, and surface roughness. Sandblasting in orthodontics has been implemented to improve the bond strength of new brackets/bands or to remove adhesive remnants from debonded brackets prior to rebonding.71 However, in vivo data from a randomized trial indicate that no significant difference exists in the bond failure rates of sandblasted and non-sandblasted brackets or in the ARI of debonded brackets.72 Finally, sandblaster has also been implemented directly on the tooth enamel surface as an alternative or adjunct to conventional acid-etching techniques, but as no randomized trial exists on this subject, the efficacy cannot be assessed in an evidence-based way at the present time. Grit-blasting or sandblasting, if available, may also be used. A specially-trained operator is needed to produce uniformity within pieces by sand blasting tank. A clean, uniform-size grit is essential for proper surface preparation with sandblasting. This may be a problem when treating GPR surfaces, and for that reason this technique is rarely used. After sanding or sandblasting, the surface is sometimes wiped with solvent such as MEK, acetone, toluene, trichloroethylene, Freon? TF, or Freon? TMC, depending on the known mold lubricants. In some cases, a solvent is used before and after abrading the surface. If water-break-free surfaces are not obtained, the procedure should be repeated. Glass-reinforced plastic laminates prepared for bonding by hand- and machine-sanding can be stored to 30 days at 23°C and 50% RH with no adverse effect on bond strength. Machine sanding gave slightly better results than hand sanding. Tear ply and sanding gave about the same results, but the tear-ply method has less risk of surface contamination. Variations in bond strength are more likely to occur as a result of changes in sanding techniques than by the difference in methods. In general, bond quality diminished with increased surface exposure time (SET). The best overall adhesive evaluated was epoxy film adhesive, which was found to be the least sensitive to the method of surface preparation. In general, the best result was obtained when GPR laminates were bonded within four hours after sanding. If absolutely necessary, bonding can be carried out after periods of time up to 14 days SET with only moderate strength loss. Brass is an alloy of copper and zinc. Sandblasting or other mechanical means of surface preparation may be used. Shot peening (which is a similar process to sandblasting, but has more controlled peening power, intensity, and direction) is a cold working process in which the surface of a part is bombarded with small spherical media called shot. Each piece of shot striking the material acts as a tiny hammer, imparting to the surface small indentations or dimples. In order for a dimple to be created, the surface fibers of the material must be yielded in tension. Below the surface, the fibers try to restore the surface to its original shape, thereby producing below the dimple a hemisphere of cold-worked material highly stressed in compression. Shot-peening (which is a similar process to sand blasting cabinet, but has more controlled peening power, intensity, and direction) is a cold working process in which the surface of a part is bombarded with small spherical media called shot. Each piece of shot striking the material acts as a tiny hammer, imparting to the surface small indentations or dimples. In order for the dimple to be created, the surface fibers of the material must be yielded in tension. Below the surface, the fibers try to restore the surface to its original shape, thereby producing below the dimple a hemisphere of cold-worked material highly stressed in compression. Injection-molded samples of PP were exposed to oxygen plasma and SACO (SAndblasting and COating) treatments. The pretreated surfaces were successively adhesively bonded or lacquered. Any successful rehabilitation measure demands proper preparation of the structural element. This includes surface preparation, such as dry sand blasting tank, of the concrete to a desired degree, storage of fiber and resin constituent materials, as well as mixing of the resin system. On-site processing, if performed incorrectly, contains a high potential for flaw introduction. It further necessitates assessments with regards to the integrity and bond capability of the concrete substrate. In some cases, cracked or split concrete sections may contain wide cracks that must be injected with resin prior to application of the composite-strengthening system. Defects induced by preparation and site processing are listed below. Improper storage of the resin system, as well as the hardener/catalyst, can lead to significant moisture absorption. If stored under inappropriate conditions – such as extreme cold, heat, or humidity – resin properties may change dramatically with time. In addition, as discussed previously, shelf life must be monitored to assure sufficient reactivity and viscosity. Difficulties may arise with systems that show inadequate stoichiometry. Resin and hardener/catalyst must be compatible and of adequate mechanical and chemical properties for the job at stake. For all resin systems, the hardener/catalyst ratio must be determined very carefully to prevent premature gelling or loss of matrix strength. During mixing, several defects may be introduced to the system, and consequently to the laminate itself. Firstly, if using rotary mixers, air can be drawn into the resin and remain as small air bubbles, leading to laminate porosity. In some cases, this porosity may later result in the formation of air bubbles of much larger diameter (millimeter range). A high number of roller passes are thus required to remove porosity from laminates that have been infiltrated with air-rich resin systems, since it is known that in the range from zero to 5%, each 1% increase in void content decreases interlaminar shear strength by about 10% (Ghiorse, 1993). Consequently, mixing must be performed at a slow rate and without drawing an excessive amount of air into the matrix. In contrast, a low degree of mixing can result in chemical inconsistency, meaning that some regions contain high percentages of reactant, while others may contain no reactant at all. Secondly, the efficacy of the resin system depends on the appropriate use of mix ratio. Errors in mix ratio can result in under cure, extreme lack of even gel and vitrification, premature gelation, or local hot spots and runaway exotherms resulting in degradation. Like resin, fibers are susceptible to moisture accumulation; however, accumulated moisture does not alter the performance of individual fiber tows. Instead, the bond to the surrounding matrix is severely weakened. Since fibers can be directly exposed to the environment, conditions must be monitored more closely than in the case of a sealed resin container. If visual detection shows a significant amount of moisture accumulation on the fiber surface, they must be discarded. When a moist fabric is infiltrated, it will experience a weak bond to the surrounding matrix. Debonding and subsequent delamination are likely to result. To obtain adequate force transfer between the retrofit material and the concrete substrate, concrete preparation is essential. This includes thorough surface preparation to a specified degree and filling of concrete cracks. Large, deep cracks propagating into the concrete may contain water that can destroy the composite–concrete interface bond and should therefore be injected prior to rehabilitation. Cracks propagating at shallow depth can promote failure in the substrate. As such, the retrofit becomes ineffective. Concrete is a porous material and hence absorbs liquids. Moreover, due to abrasion of cement paste during sand blasting room, a large number of small to medium diameter voids become exposed on the concrete surface. Prior to application of the composite overlay, regardless of type, a compatible primer coat should be applied. The role of this primer is to fill voids and quench the absorption so that the surface is prepared for the subsequently applied composite material. If primer coatings are omitted, the saturating resin would be to an extent absorbed. In addition, the primer presents a ‘bondable’ surface. To ensure an intimate bond between composite and concrete, the thickness of the coating should be kept as thin as possible. If excessive amounts of primer are used, low stress transfer capabilities and resin dripping can result. Marking of areas that require strengthening is generally done using a chalk line. However, care must be taken not to cause separation between the layup and base material by applying a material that cannot be penetrated by the resin/adhesive, or that could cause edge debonding, which not only serves as a weak zone but also a potential initiator for bond degradation. If the concrete substrate displays a high degree of microcracking at its surface, the composite overlay must bond to an initially weak base material. In extreme cases the degraded cover material may need to be completely removed and replaced by appropriate fillers, prior to rehabilitation. Naturally, many structures in need of rehabilitation already show a large number of cracks, which may have opened to a significant degree and thus accumulated moisture, dirt, or other foreign material over time. By applying a primer coating, inclusions may become permanently encapsulated within the surface to serve as weak spots for future crack initiating and propagation at the interface level. As a preventive measure, cracks should be cleaned and injected with appropriate filler materials, depending on the depth and diameter of the crack. To provide a smooth surface for bonding, any irregularities such as form lines or protruding aggregate should be ground down. If a composite laminate is applied to concrete surfaces that contain high spots, the laminate will tend to form an air pocket. Similarly, large, hollow regions, which may result from high spots in the formwork, must be filled prior to composite application. Carbon fibers, when in direct contact with steel, cause the formation of a galvanic cell, which results in the accelerated corrosion of steel and degradation of the matrix in the composite (Woo et al., 1993). In spalled, or otherwise substantially degraded concrete components the loss of cover concrete can result in this interaction. Thus appropriate levels of concrete rebuilding are essential prior to the placement of the fiber.
Дата Публикации: 18-11-21
Ball Valve - How They Work
Описание: Ball Valve - How They Work A ball valve is a shut off valve that controls the flow of a liquid or gas by means of a rotary ball having a bore. By rotating the ball a quarter turn (90 degrees) around its axis, the medium can flow through or is blocked. They are characterized by a long service life and provide a reliable sealing over the life span, even when the valve is not in use for a long time. As a result, they are more popular as a shut off valve then for example the gate valve. For a complete comparison, read our gate valve vs ball valve article. Moreover, they are more resistant against contaminated media than most other types of valves. In special versions, ball valves are also used as a control valve. This application is less common due to the relatively limited accuracy of controlling the flow rate in comparison with other types of control valves. However, the valve also offers some advantages here. For example, it still ensures a reliable sealing, even in the case of dirty media. Figure 1 shows a sectional view of a ball valve. Standard floating ball valves consist of the housing, seats, ball and lever for ball rotation. They include valves with two, three and four ports which can be female or male threaded or a combination of those. Threaded valves are most common and come in many varieties: with approvals for specific media or applications, mini ball valves, angled ball valves, ISO-top ball valves, with an integrated strainer or a bleed point and the list goes on. They have a wide range of options and a large operating range for pressure and temperature. For more information on a threaded connection, read our trunnion ball valve connection types article. Hydraulic Hydraulic ball valves are specially designed for hydraulic and heating systems due to their high operating pressure rating and hydraulic and heating oil resistance. These valves are made of either steel or stainless steel. Besides these materials, the seats also make hydraulic valves suitable for high operating pressure. The seats of these valves are made of polyoxymethylene (POM), which is suitable for high pressure and low temperature applications. The maximum operating pressure of hydraulic ball valves goes above 500 bar while the maximum temperature goes up to 80°C. Flanged ball valves are characterized by their connection type. The ports are connected to a piping system via flanges that are usually designed in accordance with a certain standard. These valves provide a high flow rate since they typically have a full-bore design. When choosing a flanged ball valve, besides the pressure rating, you also have to check the flange compression class which indicates the highest pressure this connection type can withstand. These ball valves are designed with two, three or four ports, they can be approved for specific media, have an ISO-top and everything else a standard quarter turn valve could have. They are typically made out of stainless steel, steel, or cast iron. For more information on a flanged connection, read our electric actuator ball valve connection types article. Vented ball valves look almost the same as the standard 2-way ball valves when it comes to their design. The main difference is that the outlet port vents to the environment in closed position. This is achieved by a small hole that is drilled in the ball and in the valve body. When the valve closes, the holes line up with the outlet port and release the pressure. This is especially useful in compressed air systems where depressurization provides a safer working environment. Intuitively these valves look like 2-way ball valves while in fact they are 3/2-way due to the small borehole for venting. To understand the working principle of a ball valve, it is important to know the 5 main 1 piece carbon steel ball valve parts and 2 different operation types. The 5 main components can be seen in the ball valve diagram in Figure 2. The valve stem (1) is connected to the ball (4) and is either manually operated or automatically operated (electrically or pneumatically). The ball is supported and sealed by the ball valve seat (5) and their are o-rings (2) around the valve stem. All are inside the valve housing (3). The ball has a bore through it, as seen in the sectional view in Figure 1. When the valve stem is turned a quarter-turn the bore is either open to the flow allowing media to flow through or closed to prevent media flow. The valve's circuit function, housing assembly, ball design, and operation types all impact the ball valve's operation are are discussed below. The valve may have two, three or even four ports (2-way, 3-way or 4-way). The vast majority of ball valves are 2-way and manually operated with a lever. The lever is in line with pipe when the valve is opened. In closed position, the handle is perpendicular to the pipe. The ball valve flow direction is simply from the input to the output for a 2-way valve. Manually operated ball valves can be quickly closed and therefore there is a risk of water hammer with fast-flowing media. Some ball valves are fitted with a transmission. The 3-way valves have an L-shaped or T-shaped bore, which affect the circuit function (flow direction). This can be seen in Figure 3. As a result, various circuit functions can be achieved such as distributing or mixing flows. The handle is connected to the valve stem (Figure 2 number 1) and is capable of turning the valve from the open or closed position (90 degrees). If installed correctly, the valve will be open when the handle is parallel to pipe and closed when the handle is perpendicular to the pipe. Taking note of the handle direction is important to visually know if the valve is open or closed. There are additional 1 piece ball valve handle types, like lockable handles or ball valve handwheels. These operate as their names suggest. If you have a bigger ball valve or need additional torque to open or close the valve, a ball valve handle extension may be required. If your handle breaks, is miss-placed or you are converting an automatic ball valve to a manual one, you can buy ball valve handle replacements. Instead of a manual handle operation to turn the valve on or off, some valves can be fitted with an electric or pneumatic actuator as seen in Figure 4. They connect directly to the valve stem (Figure 2 number 1) and are capable of turning it a quarter turn. The most common flange connection between the valve and actuator is the ISO 5211 standard. Figure 5 shows an example of an ISO 5211 top ready to be connected to an actuator. By using an actuator, you can control your ball valve remotely or through a controller so that it can be used as an automatic shut off. A spring actuated ball valve, also called spring loaded, use a spring to open/close the valve in a power-off scenario and an actuator to then hold it in the open/close position. These are used for energy conservation applications or for fail-safe reasons. Brass has the largest market share (Figure 6). Brass is an alloy of copper and zinc and has good mechanical properties. Brass valves are used for (drinking) water, gas, oil, air and many other media. Chloride solutions (e.g. seawater) or demineralized water may cause dezincification. Dezincification is a form of corrosion where which zinc is removed from the alloy. This creates a porous structure with a greatly decreased mechanical strength. A brass housing is ideal for an air ball valve. View our manual 2-way brass ball valves or 3-way brass ball valves. Stainless steel is used for corrosive media and aggressive environments (Figure 7). They are therefore often used in seawater, swimming pools, osmosis installations, with high temperatures, and many chemicals. Most stainless steel is austenitic. Type 304 and 316 are the most common, 316 has the best corrosion resistance. 304 is sometimes referred to as 18/8 because of 18% chromium and 8% nickel. 316 has 18% chromium and 10% nickel (18/10). Stainless steel valves usually require a higher operating torque than for example brass or PVC valves. This must be taken into account when a stainless steel valve is operated by an electric or pneumatic actuator. View our manual 2-way stainless steel ball valves or 3-way stainless steel ball valves. PVC often has a lower price (except for ISO-top valves) and are widely used in irrigation, water supply and drainage or corrosive media (Figure 8). PVC stands for polyvinyl chloride. PVC is resistant to the most of the salt solutions, acids, bases, and organic solvents. PVC not suitable for temperatures higher than 60 °C, and is also not resistant to aromatic and chlorinated hydrocarbons. PVC is not as strong as brass or stainless steel, therefore PVC ball valves have lower pressure rating. A more in-depth article about PVC ball valves can be read here. Most valve seats are made of PTFE (Teflon). PTFE stands for PolyTetraFluorEthylene. This material has a very good chemical resistance and a high melting point (~327°C). Besides that, the friction coefficient is extremely low. A small disadvantage of PTFE is that the material shows creep, which can cause a deterioration of the sealing over time. Besides that, PTFE has a rather high thermal expansion coefficient. A solution for this problem is to use a spring in order to apply a constant pressure on the Teflon seal, like for example a cup spring. Other popular sealing materials are enforced PTFE and Polyamide (Nylon). The harder the material of the valve seat is, the more difficult it is to maintain proper sealing. For some application in which soft materials are not possible to use, for example with very high temperatures, metal or ceramic valve seats are used. Approvals For certain applications, approvals are desired or required. Drinking water and gas are the most common. Choosing a certified 2 piece floating ball valve, assures that the product meets important safety requirements. Drinking water These ball valves are suitable for drinking water applications and have a WRAS, KIWA or DVGW approval. If being used with a water holding tank, they often work in connection with a float switch to monitor water level. Ball valves are widely used for large size piping in the subsea manifolds. In addition, small bore ball valves in size ?″ and ?″ can be used in subsea distribution units on the piping system to be used for delivering chemicals and hydraulic oil. This chapter reviews the application, design features, and design standards of the subsea ball valves. The concept of double piston effect seat design as well as double isolation and bleed (DIB) type 1 and 2 is explained in this chapter. Different components of a typical ball valve with the possible materials have been reviewed in this chapter. Different quality control methods and approaches are briefly explained. In addition, special ball valves such as three port or three way ball valves are also explained in this chapter. A ball valve consists of a valve body in which a large sphere with a central hole equal to the inside diameter of the pipe is mounted. As the ball is rotated, in the fully open position the valve provides the through conduit or full bore required for unrestricted flow of the fluid and scrapers or pigs. Compared with a gate valve, a ball valve has very little resistance to flow in the fully open position. When fully open, the L/D ratio for a ball valve is approximately 3.0. The ball valve, like the gate valve, is generally used in the fully open or fully closed positions. A typical ball valve is shown in Figure 12.10.
Дата Публикации: 18-11-21
Air Fryer
Описание: Air Fryer If you are a family of two, you can make easy meals with a small air fryer. While there are many different sizes of air fryers available in the market, for a family of two, an air fryer from 2 to 4 quarts will be ideal. As these air fryers are small in size, they do not take much space on the kitchen shelf, and they cook ample food for two family members. You can cook a variety of meals in these air fryers without causing any food wastage. In this article, we will take a look at some of the popular air fryers that are ideal for a family of two. We will also compare each air fryer’s features along with the pros and cons of each air fryer. GoWISE is a well-known brand for air fryers of all sizes. You can find the GoWISE USA 3.7 quart air fryer ideal for the needs of a small family. If there are only two people in the family, this air fryer will suit their needs to cook quick meals of all kinds. The air fryer takes up little space on the kitchen counter and comes with a range of features that make air frying food fun and easy. There are eight presets on the 2.4l air fryer, and you can choose the dish you want to make from the buttons on the panel of the air fryer. The temperature and time settings are also available on the panel. The air fryer is ideal for cooking everything from chicken to french fries, fish, steak, pork, shrimp etc. The food is healthy to eat as it uses very little to no oil, and you can cook in the air fryer without the need to mess with oil or flames. The NUWAVE BRIO is a 3-Quart air fryer that makes the ideal amount of food for two people. If you have a small family, you can get this air fryer to cook food in small batches. The air fryer also has an air-flow design that makes delicious food quickly and efficiently. Another interesting feature is the Flavor-Infusion technology that allows you to cook food without needing to defrost it before putting it in the air fryer. The air fryer has an extensive cooking range so that you can cook all kinds of food at temperatures ranging from 100F to 400F. You can also choose from different cooking options depending on the dish that you want to cook. Whether you want to air fry, roast, grill, bake or reheat food, you can do it all. This is a small-sized air fryer that does not take too much space in the kitchen. You can also keep this 2.6l air fryer in a dorm room, a van, or an RV as needed. If you are looking for a small, powerful, and efficient air fryer, this is the machine you want to pick. The DASH compact electric air fryer is a small-sized machine ideal for a family of two. You can fry your favorite food without worrying about the excess of oil in the food. The air fryer cooks the food with superheated air that does not add to the meals’ calories. You can cook food in this air fryer by using any one of the five presets for cooking the most common types of food. The basket in this air fryer has a small capacity that is enough food for two people. The air fryer is quick to heat up, and it cooks food quickly with its powerful heating mechanism. There is also an auto shut-off function that prevents the food from overcooking. You can clean the air fryer in the dishwasher as well. With the range of dishes that you can cook in this air fryer, you will never feel a lack of your favorite foods to eat. The DASH air fryer is also small in size so that it won’t take too much space on your kitchen shelf. If you are looking for a lightweight and straightforward air fryer, this is the unit you should pick. To sum up, if you have a small family, it makes sense to get an air fryer that has a capacity of anywhere from 2-4 quarts. This quantity is ample for cooking quick and small meals that are healthy and delicious. An air fryer for a family of two means you can cook exactly how much you want to eat to prevent food wastage. The small air fryer cooks the food quickly, and there are several dishes that you can try in the 3.5l air fryer. Also, even if the air fryer is small, it does not mean that you will lack any features or frying power in the air fryer. The small air fryer will also take less space on the kitchen counter so that you can maintain the decor and cleanliness in your kitchen. For any doubts about air fryers for a family of two, please feel free to leave a comment, and our team will answer you at the earliest. Planning to buy Air Fryer on Black Friday deals and looking for good airfryer black friday deals? Then you are in the right place. Here we try to collect some of the best black friday air fryer deals 2020. Black Friday is one of the most famous online shopping day where almost all sellers and retails offers a huge discount on products. We will keep updating the above Air fryer black friday deals regularly so keep visiting this page to see new black friday airfryer deals. Black Friday comes once a year, and all users will be eagerly waiting to grab their favorite products at the best price. But finding products which are offering a good discount can be a difficult task sometimes. Don’t worry. We are going to help you to bring all black friday air fryer deals 2020 here, so you don’t need to check any other places. We are going to list only Airfryer deals here, but don’t limit yourself by just buying air fryers. Because who doesn’t like to get the product at a cheaper price? So grab all the stuff you need without thinking. Black Friday celebrated 27th November 2020. But you don’t need to wait till that day. Some sellers start offering 4l air fryer black friday deals a few days before itself so grab it before it gone. I recommend you visit this page on Amazon to know the latest Black Friday lightning deals are going on right now. An 8-quart air fryer can help you to cook a lot of food in a single cooking cycle than smaller air fryers. If you have a large family or you like to have guests over, an 8-quart air fryer can add to your cooking capacity in the kitchen. The best part is that cooking food in the air fryer is as easy as putting the food in, and choosing the time and temperature as per the recipe. You can rest assured that the food cooked in the air fryer is healthy as you are not using oil to fry the food. The food is prepared by superheated air in the air fryer, with minimal fat. As a result, there are fewer calories in the food, and you can enjoy your favorite fried snacks while keeping an eye on your health. Using the air fryer is easy as you can set up the time and temperature according to the dish that you want to cook. The air fryer does the rest and you just have to wait for your food. In this article, we are going to take a look at some popular 8-quart air fryers. We will also compare their features and take a look at their pros and cons. This unique product is an instant pot that also works as an air fryer. The Instant Pot Duo Crisp can be converted from a pressure cooker to an air fryer by merely switching the unit’s lid. There are eleven one-touch cooking programs available for this air fryer that make it a useful appliance in any modern kitchen. The air fryer can be used for several cooking functions that range from pressure cooking to slow cooking, air frying, roasting, baking, broiling, and much more. You can also cook chicken in this air fryer to give it a crispy golden finish that leaves the chicken tender and juicy from the inside. There are several useful accessories provided with the air fryer that add to the cooking experience. The multi-level air fryer basket is excellent for cooking more food in one cooking cycle. The broiling tray offers optimum airflow to expedite cooking. With the ample cooking capacity provided in this air fryer, you can cook food for up to eight people. Several safety features are built into the air fryer that prevents the food from burning up and keep the air fryer safe from overheating. If you are looking for an air fryer that will serve the functions of several appliances in the kitchen, check out this unit today. The Ninja FD401 is an air fryer that cooks quickly and has a wide range of functions to make most of your favorite dishes. You can use this air fryer for not just frying, but you can also sear, bake, steam, slow cook, dehydrate, and pressure cook in this unit. The high capacity of 8-quart is enough to cook food for a large family. Even if you have guests in the house, you can cook for them in this air fryer with ease. You can either use the 8-quart cooking pot or the 5-quart cook and crisp basket to make your favorite meals in this air fryer. What’s more, you can also layer up the bucket with inserts to increase the cooking capacity of the air fryer. The air fryer is a quick operating unit that can cook food at high temperatures and give you the texture and crispy finish that you expect. The food cooked in the air fryer tastes just like the fried food in the oil. The air fryer can cook food at 75% less fat than food that is fried in oil or fat. There are several useful cooking functions in this air fryer, such as the stay warm function that can keep food warm up to 12 hours. With all these features, this air fryer is a great addition to a kitchen as it can help you to cook different types of dishes with ease. If you are looking for a premium cooking experience, then check out this air fryer today. This air fryer from Ultrean is an 8-quart unit that comes with a 360-degree Rapid Air Frying Technology. The air fryer is perfect for cooking food without the use of any oil. Whether you are cooking chicken, french fries, steak, or vegetables, you can use this air fryer to get excellent results for all your meals. The all-in-one air fryer also roasts, grills, and bakes all kinds of meals, and it can be an excellent replacement for most of the appliances in your kitchen. The extensive capacity of this air fryer means you can easily cook food for 6-8 people. You can also use the air fryer for cooking a large batch of food as a food prep so that you do not need to cook more food in the whole week. If you want to make healthy eating a part of your life, an air fryer can work wonders in helping you to build that habit. With easy to use features, this air fryer comes with auto shut off and overheat protection so that your food doesn’t get burnt. The programs on this air fryer are easy to understand as the large LCD panel has soft buttons that you can press to choose the options you need. The accessories for this air fryer are dishwasher safe, and you can clean them in the dishwasher with the rest of the utensils. If you are looking for a reliable unit that will add to your cooking skills in the kitchen, then check out this air fryer today.
Дата Публикации: 18-11-21
How to choose the right retractable monitor?
Описание: How to choose the right retractable monitor? A retractable LCD monitor for use in aircraft and the like is supplied with power from a power supply that is secured in a fixed off-monitor location on the monitor's housing. The power supply also provides power for a motor assembly that controls a pivoting of the monitor between open and retracted positions. This configuration allows for a compact monitor assembly that can be stowed screen up within a restricted space housing, thus protecting the display from damage by passengers and presenting a pleasing appearance, while still pivoting the monitor by more than 90° to its open position. The motor that is used to pivot the monitor to the open position remains coupled to the monitor pivot mechanism during the retraction cycle, providing a back-emf that resists a spring force used to retract the monitor, and thereby cushion its retraction. A game machine has a display part connected so as to freely enable storage within a seat on which a player sits. The game machine has a display part for showing game images generated according to a game program and player input, an input reception part for receiving input from the player, a control part for executing the game program according to predetermined external input, including input from the input reception part, a seat part for enabling the player to sit, a storage part for storing the display part formed in the seat part, and a connection rod for connecting the display part to the storage part such as to freely enable storage thereof, of which one end is fixed to the seat part and the other end is connected to the display part. Arthur Holm is launching its first 24-in 4K motorized retractable monitor during ISE 2018, held next month in Amsterdam. The DB2 has 20° of adjustable inclination, the housing is made from solid aluminium and the operation button is placed on the top of the screen. The monitor provides a 2mm. double-sided anti-reflective black edged glass. The motorized retractable monitor with fixed tilt is configurable by way of a secondary LCD 2.2-in display, and by remote control, being able to be configurable and operational without having to remove the monitor from the furniture. When the display is connected to the AH ERT interface, the intuitive addressing system facilitates the address configuration easier due to a single accessible push button. The unit provides embedded speed and protection pre-sets to restore factory values and an auto-check diagnostic and internal protection functions as well as an auto calibration mode for mechanical speeds and safety parameters .It is firmware upgradeable through a USB port. A safety system detects obstructions (in this eventuality the unit stops). The adjustable mechanical parameters are operational via AHnet or ISD for calibration and mechanical adjustments. Adjustable parameters of brightness, contrast and backlight are available via RS- 422. An auto calibration mode is available for mechanical speeds and safety parameters. So, your screen, cheap or expensive, if it is non-tensioned (cheap ones aren't) will likely have or develop waves. All of this matters because of throw distance. Think about what is going on with a short throw or ultra short throw projector. These projectors throw an image at a very sharp projection angle. This creates a requirement for an absolutely flat screen surface. Any waves or bends to the screen cause severe distortion. Especially towards the edges and the top of the screen. The solution to this problem is adding more distance between the projector and the screen. The further away the projector is from a wavy screen the less impact the waves on the screen will have on the projected image. So, yes, you can use short or ultra short throw, but you can't use an inexpensive roll-up screen. In fact, you may need a several thousand dollar screen to accommodate a short throw solution. Of course, you can always opt for using a wall or a fixed-frame screen to save money. But, if you absolutely have to use a retractable monitor for room design reasons and don't have the budget for a good tensioned model, you will want to place the projector as far from the screen as possible. In that case, it may make sense to go with a more affordable roll-up screen and put the savings into paying an installer to mount a more conventional projector at the back of the room where minor waves and ripples in the screen surface won't be an issue. Just make sure that the projector you select has the appropriate lens to handle a high shelf installation if that's what you've got in mind. Many projectors require a projector mounted near the ceiling to be inverted as they would for a ceiling mount. Paul Vail has been a professional audiovisual engineer since 1999. He works day-to-day for a commercial integrator and runs his own residential installation company, AV Integrated, out of Chantilly, VA, covering the greater Washington D.C. area. He has been the moderator of the ProjectorCentral Big Screen Forums from their inception more than ten years ago and has installed hundreds of projectors over the years, from entry level basement setups to 4K simulation systems using the latest in 3-chip DLP technology. He enjoys helping others learn about how to get the most value for their money, and setting realistic expectations and goals for the setup they are working toward. You can submit your question for Paul and ProjectorCentral Q&A by clicking here. If you’ve decided a retractable patio screen is a right fit for your home, the next step is choosing the right one. There are plenty of different materials, types of mesh, and even designs to choose from. It can be hard to choose, but the screen you decide on will be part of your outdoor living space for a long time. Look at this guide to figure out what features to look for. How to choose the right retractable monitor with microphone Want to make sure you have the right screen for your outdoor space? Consider these things when you make your choice. What are its uses? Are you interested in a retractable patio screen simply to keep bugs out? Do you also want extra shade or protection for other critters? Depending on what you want to use it for, certain types of screens will be a better fit. Most screens do protect from insects and offer some degree of shade. Retractable screens are ideal for keeping bugs out while letting you enjoy the view and maximum ventilation. On the other hand, sun-blocking screens are darker, but keep your patio cool, however, offer less of a breeze. Maintenance and installation Retractable screens don’t often require much maintenance, although it’s a good idea to wipe them down and apply silicone spray every 6 months just to keep them moving smoothly. Aesthetic options While a retractable patio screen should do its job, it can also offer beauty and elegance to your outdoor space. Depending on the style and material you use, you’ll have a variety of options. Look for a motorized retractable monitor with motorzied adjustable tilt that matches the appearance of your outdoor living spaces. Conclusion Patio screens have undergone vast improvements in recent times. Now, there are convenient, durable, and attractive patio screens that retract when you’re not using them. There’s more to choosing a screen than just picking the one encloses the opening. Use this guide to help you determine which features are most important for your screen, and your outdoor living spaces. Six months ago we did a story on a newly designed, commercial aircraft retractable monitor with its developer and designer, Yukio Sugimoto. If you have a technical bent you may remember that his product was an engineer’s dream, instead of the mechanical nightmare that historically plagues these devices. In all fairness, the restrictions and requirements on retractable monitors are moderately onerous, especially considering the fact that they must operate with power that is subject to dropping out… not to mention issues like the video display retract necessity under loss of power or in emergency situations. (Editor’s Note: There is a qualification test requirement (RTCA DO-160 currently version “F”) which says that avionics equipment must withstand 250 milliseconds of power interruption and this poses some difficulty to electro mechanical equipment like retractable monitors. The real FAA requirement issue is: How does one design the monitor to close when airplane power is lost? With loss of power, the first generation retractable monitor systems that use mechanical springs and other additional parts, like clutches and control mechanisms, have generated a lot of problems in, resulting in lower reliability units.) This also explains the high mechanical parts count and resultant weight increase, not to mention stored energy springs to facilitate zero power retractions. As we noted in the earlier article, the ACS patent pending solution involves storing energy in capacitors – that’s the simple answer but it is a circuitry design solution as well! When we got wind of the retract we wondered like you probably did – the market for retractable units must be dropping, in part because of their past reliability issues with retracts – perhaps the highest MTBF of any IFE LRU. We asked Richie about the demand for retracts. “Here is where we are ahead of the market and our answer is buried in airline operational cost increases… our product will be an airline cost saver!” He went on, “Keeping those operational costs down is the name of the IFE game today, and our retract is a game-changer, especially for value driven airlines and airlines that are seeing a lot of onboard passenger use of their own entertainment devices (PED’s). Let’s face it, it costs an airline a lot of money to install and pay for the recurring costs (maintenance, content, and fuel) of a multiple displays while many watch their own PED movies or work on laptops instead. Look at it this way, both retractable overhead and seatback devices can do an approved job of delivering the safety briefing but as an airline, which would you rather pay for, especially if the overhead units cut the maintenance costs by 80 per cent!” While the market for retractable monitors is falling off, no one knows the effect of personal, carry-on devices. There is an argument for pay-per-click revenue in seatback solutions but the ACS team pointed out that on any flight under 1 ? hours or so, that revenue model falls apart, not to mention the challenge of showing full-length movies. Subtract the 30 minutes lost after take-off and before landing and the model might even extend to longer flights. “The message is simple,” noted Richie, “airlines that want to cut costs and airlines that fly in short haul markets need to take a new look at retractable monitors… not to mention routes where passengers bring their own devices! The costs are unbeatable – overhead monitors have a 9 to 1 display advantage. One monitor can serve 9 passengers.”
Дата Публикации: 18-11-21