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How well do face masks protect against coronavirus?
Описание: How well do face masks protect against coronavirus? Can face masks help slow the spread of the coronavirus (SARS-CoV-2) that causes COVID-19? Yes. Face masks combined with other preventive measures, such as getting vaccinated, frequent hand-washing and physical distancing, can help slow the spread of the virus. The U.S. Centers for Disease Control and Prevention (CDC) recommends fabric masks for the general public. If you're fully vaccinated and are in an area with a high number of new COVID-19 cases, the CDC recommends wearing a mask indoors in public and outdoors in crowded areas or when you are in close contact with unvaccinated people. People who haven't been fully vaccinated should wear face disposable masks indoors and outdoors where there is a high risk of COVID-19 transmission, such as crowded events or large gatherings. The CDC says that surgical N95 masks should be reserved for health care providers. Respirators such as KN95s and non-surgical N95s can be used by the general public when supplies are available. The World Health Organization (WHO) recommends medical masks for health care workers as well as for anyone who has or may have COVID-19 or who is caring for someone who has or may have COVID-19. How do the different types of masks work? Medical masks Also called surgical masks, these are loosefitting disposable masks. They're meant to protect the wearer from contact with droplets and sprays that may contain germs. A 3ply medical disposable mask also filters out large particles in the air when the wearer breathes in. To make medical masks more form-fitting, knot the ear loops where they attach to the mask. Then fold and tuck the unneeded material under the edges. N95 masks An N95 mask is a type of respirator. It offers more protection than a medical mask does because it filters out both large and small particles when the wearer inhales. Non-surgical N95s can be used by the general public when supplies are available. The CDC has said surgical N95 masks should be reserved for health care providers. Health care providers must be trained and pass a fit test before using a surgical N95 mask. Like surgical masks, N95 masks are intended to be disposable. However, researchers are testing ways to disinfect and reuse them. Some N95 masks, and even some cloth masks, have valves that make them easier to breathe through. Unfortunately, these anti-dusk masks don't filter the air the wearer breathes out. For this reason, they've been banned in some places. Cloth masks A cloth mask is intended to trap respiratory droplets that are released when the wearer talks, coughs or sneezes. It also acts as a barrier to protect the wearer from inhaling droplets released by others. The most effective cloths masks are made of multiple layers of tightly woven fabric like cotton. A mask with layers will stop more droplets from getting through your mask or escaping from it. How to get the most from your mask The effectiveness of cloth and medical masks can be improved by ensuring that the masks are well fitted to the contours of your face to prevent leakage of air around the masks' edges. Masks should be snug over the nose, mouth and chin, with no gaps. You should feel warm air coming through the front of the mask when you breathe out. You shouldn't feel air coming out under the edges of the mask. Masks that have a bendable nose strip help prevent air from leaking out of the top of the mask. Some people choose to wear a disposable mask under their cloth mask. In that case, the cloth mask should press the edges of the disposable mask against the face. Don't add layers if they make it hard to breathe or obstruct your vision. Proper use, storage and cleaning of masks also affects how well they protect you. Follow these steps for putting on and taking off your mask or disposable glove: Wash or sanitize your hands before and after putting on your mask. Place your mask over your mouth and nose and chin. Tie it behind your head or use ear loops. Make sure it's snug. Don't touch your mask while wearing it. If you accidentally touch your mask, wash or sanitize your hands. If your mask becomes wet or dirty, switch to a clean one. Put the used mask in a sealable bag until you can get rid of it or wash it. Remove the mask by untying it or lifting off the ear loops without touching the front of the mask or your face. Wash your hands immediately after removing your mask and protective garment. Regularly wash cloth masks in the washing machine or by hand. (They can be washed along with other laundry.) And don't forget these precautions: Don't put masks on anyone who has trouble breathing or is unconscious or otherwise unable to remove the mask without help. Don't put masks on children under 2 years of age. Don't use face masks as a substitute for physical distancing. What about face shields? The CDC doesn't recommend using face shields instead of masks because it's unclear how much protection shields provide. However, wearing a face mask may not be possible in every situation. If you must use a face shield instead of a mask, choose one that wraps around the sides of your face and extends below your chin. Do you still need to wear a facemask after you're fully vaccinated? After you are fully vaccinated, you can more safely return to doing activities that you might not have been able to do because of the pandemic. However, if you are in an area with a high number of new COVID-19 cases, the CDC recommends wearing a mask indoors in public and outdoors in crowded areas or when you are in close contact with unvaccinated people. You're considered fully vaccinated 2 weeks after you get a second dose of an mRNA COVID-19 vaccine or 2 weeks after you get a single dose of the Janssen/Johnson & Johnson COVID-19 vaccine. In the U.S., everyone also needs to wear a mask while on planes, buses, trains and other forms of public transportation.
Дата Публикации: 02-11-22
7 Benefits of Centrifugal Chemical Pumps
Описание: 7 Benefits of Centrifugal Chemical Pumps Centrifugal chemical pumps are ideal for many applications, from filtration and circulation to storage and unloading. Due to their harsh nature, corrosive chemicals must be handled carefully. As designers establish their systems, they must select pumps that are constructed to withstand the specific corrosive chemicals involved in their process. Centrifugal Chemical Pump Types Centrifugal pumps are available to transfer a wide range of flows. Using rotational energy supplied by an impeller, these pumps are able to move liquids safely and efficiently. Centrifugal chemical pumps are designed to transfer liquids that other pumps cannot safely handle. Centrifugal chemical pumps are manufactured in two main styles: mechanically sealed and magnetically driven. These designs are distinct and are appropriate for different applications. Pumps With Mechanical Seals A centrifugal pump features an internal rotating impeller with a portion that connects to the motor through an opening in the pump housing. To prevent leakage, a mechanical seal is used for this opening. These are typically made of ceramic, silicon carbide or carbon rings that are carefully designed to seal the pump preventing leakage. One ring rotates as the shaft turns, while the other remains stationary in the pump. As the fluid travels through the pump, a small amount moves between these two seal faces to provide lubrication. The main advantage to this type of pump is the initial purchase price. Compared to other types of pumps, such as stamping pump, sewage pump and magnetic pump, the initial investment is typically lower. A secondary advantage is the potential to handle some solids. Magnetic-Drive Centrifugal Pumps As the name implies, magnetic-drive (mag-drive) pumps are driven by magnets. This eliminates the direct connection between the impeller and the motor shaft, effectively eliminating the need for a seal. Magnets are mounted on the motor shaft to transfer the motor power through a solid barrier to other magnets inside the pump, which rotate the impeller. The key advantage to this pump style is the lack of mechanical seal. With no seal to wear out or leak, this pump style offers lower maintenance and greater longevity than mechanically sealed pumps, and also, some models feature run-dry capability not commonly found among mechanically Centrifugal Chemical Pump Benefits 1. Corrosion Resistance This benefit creates two advantages. First, the pumps allow manufacturers and processors to transfer a wide variety of fluids, even those that would quickly cause corrosion in other pumps. Second, the pumps offer long service life. Even when used for extremely corrosive chemicals, the pumps are able to withstand these conditions and deliver enhanced return on investment (ROI) (Image 4). 2. Energy Efficiency Centrifugal chemical pumps rank high in energy efficiency compared to other pumping technologies. Their efficiency reduces costs both in the short term and over the life span of each unit. 3. Smooth Flow Some pumps produce pulsing flow. Non metallic centrifugal pumps avoid pulsing. 4. Proven Reliability Centrifugal chemical pumps are a solid choice when reliability is critical. Evaluate design and construction features to ensure the specified pump will be durable enough to operate under the most extreme conditions in the planned application. 5. Low Maintenance Despite long life spans, some pumps may require frequent routine maintenance that can make them costly to operate. Fortunately, centrifugal chemical pumps have low routine maintenance requirements. 6. Size Versatility Centrifugal chemical pumps are available in a wide range of sizes. The various models can accommodate flow rates ranging from less than 1 gallon per minute (gpm) (1 liter per minute ) to greater than 1,400 gpm (318 cubic meters per hour ). 7. Application Versatility The same pump configuration is not suitable for every application. With centrifugal chemical pumps, various configurations are available to provide solutions for multiple applications. These versatile pumps are available in three configurations: A. Flooded suction—These can be used when the liquid supply level is above the pump's centerline or impeller eye. B. Self-priming—These can be used when the liquid supply level is below the pump's centerline or impeller eye. C. Vertical—These pumps are typically submerged in the fluid, making them suitable for applications where space is limited. Some manufacturers offer standard, nonsubmergible pumps that can be mounted vertically outside the tank to save space. Furthermore, the option of mechanical seal or magnetic drive sealless designs adds to the versatility of these pumps. These two constructions cover a full range of applications. This diversity also covers a range of budgets, making it easier to find a pump that is suitable for each unique use. Specifying a Centrifugal Chemical Pump To spec the ideal pump for any application, the pump supplier needs key pieces of information. To provide the required information, consider these questions about the fluid and the application. About the Fluid What is the name of the fluid(s) the pump will transfer? This may include more than one name if there will be a mixing of products or the fluid is a mixture of chemicals. What is the concentration of the fluid? This helps determine the chemical's level of corrosivity. What is the fluid temperature? Chemical resistance can vary by temperature, so this quality is important to note. What is the specific gravity of the fluid? This is used to select the correct motor power and lift capacity. What is the viscosity of the fluid at pumping temperature? This affects the flow, head and motor power of the centrifugal pump. Will the pump be used for solids? If so, the user must identify the hardness, particle size and concentration of the solids. These details affect the material specs of the pump. Is the fluid flammable or combustible? This affects what components and materials are used for the construction of the pump. About the Application What is the total head? This is based on the piping system and is used for reviewing a manufacturer's pump head-capacity curves. What is the flow rate? This is the volume of liquid that needs to be pumped per unit of time. What is the net positive suction head available (NPSHa)? This is the suction head made available to the pump and provided by the piping system, which must be taken into consideration to avoid damage to pump components. What is the application? A detailed description of how the pump in automatic control system will be used allows the manufacturer to spec the appropriate pump. What other materials are involved? Some materials may be suitable for some chemicals, but they can be negatively affected by certain combinations of products. What is the ambient temperature range? In settings where the temperature is not controlled, this must be taken into account when selecting the motor and construction materials. What is the atmosphere environment? This helps determine the motor enclosure type. What is the altitude? Atmospheric pressure affects maximum lift, NPSHa and motor cooling ability. Using the information about the fluid and application, partner with pump manufacturers and knowledgeable, experienced pump distributors in order to specify the correct pump type and the materials of construction to handle the chemicals involved.
Дата Публикации: 02-11-22
Common Types of Pneumatic Valves
Описание: Common Types of Pneumatic Valves Pneumatic valves are one of an array of components responsible for controlling the pressure, rate, and amount of air as it moves through a pneumatic system. Pneumatic systems, which depend on the force of compressed air to transmit power, can be found in countless industrial flow control applications, from pneumatically operated power tools to diesel engines. Based on other components within a given application and the type of pneumatic system used, one of several types of pneumatic control components valves may be found at the heart of the device. This article will review the common types of pneumatic valves that are used in the industry and provide information on the configurations and key specifications associated with these devices. To learn more about other types of valves, see our related guide on the types of valves. For an understanding of pneumatic actuators, see our guide all about pneumatic actuators. Pneumatic Valve Use Context The term "pneumatic valve" generally has two distinct contexts of use which require some explanation. In the first context, a pneumatic control valve is a device that is used to control or modulate the flow of air (or another inert gas) in a pneumatic system. They do so by controlling the air or gas at the source, regulating its passage as needed into tubing, pipes, or devices in an automated pneumatic system. The actuation component that causes the pneumatic valve to open or close might be accomplished in any of several ways, including manually, electrically via a solenoid valves or motorized actuator, or pneumatically. The key concept to note in this case is that it is pressurized air or gas that is being controlled and which is flowing through the valve ports in the pneumatic system. In the second context, air is being used as the control mechanism on the valve, but the media that is flowing through the valve ports is something other than air, perhaps water, oil, or some other fluid. In this context, the pneumatic air valve is functioning to provide flow control in a valve, but the fluid being controlled is not air. The air is serving as the control media, being passed through a pneumatic actuator to open, close, or modulate flow as needed. These valves are therefore sometimes referred to as pneumatically-actuated valves. To summarize, in the first context, air is being controlled but may or may not be driving the control mechanism of the valve. In the second context, something other than air is being controlled but the control mechanism is air. A distinction between these two general contexts will help with a further understanding of pneumatic valves and their uses. The types of pneumatic valves below are generally representative of the first context. Types of Pneumatic Valves Pneumatic valves, also called directional control valves, may be classified using several different approaches which include: the number of entry and exit ports they possess the number of flow paths or switching positions that are available the mechanism that is used to open or close the ports the position the valve is in when in the un-actuated state Functional directional control valves, those that control the direction of air flow or inhibit flow all together, are a large class of pneumatic valves that houses multiple variants. These devices can be used in various ways in a hydraulic system, such as to connect or disconnect the main compressed air supply from the system or to advance or retract air compact cylinders that move as part of the machine or process for which the pneumatic actuator system has been created. With this in mind, we can broadly delineate the primary types of pneumatic valves as: Two-Way directional control pneumatic valves Three-Way directional control pneumatic valves Four-Way directional control pneumatic valves Spring offset pneumatic valves Two-Way Directional Control Pneumatic Valves A two-way directional valve passes air in two directions, through two ports which can be open or closed. If the valve ports are closed no air can flow through the valve. If the ports are open, air may move from the first port through the valve and through the second port or in the opposite direction. Three-Way Directional Control Pneumatic Valves A directional three-way air control valve has three ports, each of which serves a different purpose. The first port is used to connect the valve to an actuator or another device. The second port is connected to an airflow. The third port is used as an exhaust exit. When the first and second ports are open and the third is closed, air moves through the valve to the device. When the first and third ports are open and the second port is closed, the actuator can vent exhaust. Three-way valves are often connected to actuators in cylinders or used in pairs and connected to double-acting pin cylinders. Four-Way Directional Control Pneumatic Valves A four-way directional valve has four distinct ports, two of which connect to actuators, one that connects to a pressurized airflow, and one that serves as an exhaust pathway. They are among the most common types of valves found in pneumatic systems because the four distinct paths allow the valve to effectively reverse the motion of a motor or basic clamp cylinders. An additional port is sometimes added to a four-way valve, making it a five-ported four-way valve. A four-way valve with an additional port is often used to provide dual pressure, meaning the valve can apply one of two kinds of pressure and alternate between the two depending on what the application requires. Alternatively, the valve can use the other port as a secondary exhaust port. Spring Offset Pneumatic Valves This type of pneumatic valve classification refers to the manner in which air flow direction is switched. For example, in a two-way directional valve, the valve is either open (air flow is enabled) or closed (air flow is prevented). In order for each port to assume an open or closed position, an actuator moves a valve spool into position. To release the valve spool and return the pneumatic valve to its previous position, a spring releases the spool. A two-way directional valve that functions in this manner is also called a spring offset valve. Pneumatic Valve Designations and Configurations Within the broad classification of pneumatic valves such as two-way, three-way, and four-way, there are various combinations of valve configurations that reflect the parameters identified earlier – namely ports, switching positions, and non-actuated state (its default open or closed position). When defining these configurations, a standardized numbering system is typically used that includes two numbers separated by a slash (/). The first number is the number of ports in the valve and the second number reflects the number of switching positions. For example, a 2/2-way pneumatic valve is a valve that has two switching positions and two ports. A 3/2-way valve is a two position valve with three ports. By extension, a 4/2-way valve represents a valve that has two switching positions and four ports; a 5/2-way valve has two switching positions and five ports. Within these options, there is also the question of the non-actuated state, which relates to flow control. A 2/2-way valve could be available in a normally closed position, meaning that when it is un-actuated, the valve is closed and does not allow the flow of air between the ports. To open the valve, actuation is needed. In a normally open valve, the opposite is true – without actuation, the valve allows air flow, requiring actuation to close off the valve. In three-way valves, one port is always open. In such cases, a closed resting state usually results in blocking the air-flow port, so air isn't moving unless the device is turned on. As an example, a five-port three-position valve may have port 1 as its pressure inlet, ports 2 & 4 as work ports, and ports 3 & 5 as exhaust ports. Configurations for pneumatic valves that are commonly used include 5/3, 5/2, 4/2, 3/2, and 2/2. Pneumatic valves can be spring offset or detented. In spring-offset valves (as described above), the valve will return to the starting state or condition when any actuation is removed. In detented valves, the valve will remain in the last activated position until it is switched again by the operator. Pneumatic Valve Specifications There are specifications for pneumatic valves, some key ones of which are summarized below. These parameters are for general guidance and the reader should know that individual valve manufacturers and suppliers may characterize their valves differently. Furthermore, the exact specifications will depend on several factors such as the manifold design, desired porting, and actuation mechanism for the valve. Operating pressure or pressure range – the amount of pressure or range of pressures (for example in psi, Bars, or Pa) which the valve is rated to handle. Operating medium – the types of media that the valve can safely control. In most cases, this will be compressed air. Flow capacity or flow coefficient – a measure of the capacity of the valve to move or flow air through it, with the flow coefficient (Cv) representing the proportionality constant between the flow rate and the differential pressure. Cycle rate – the maximum number of valve cycles at which the valve can operate per unit of time. Response time – the amount of time required for the valve to switch states or positions once actuated. Port size – the physical dimensional parameters that define the port sizes on the valve and the thread style. Coil rated voltage – for electrically actuated valves, a measure of the maximum voltage that can be sustained by the actuation coil and may be rated in DC and AC volts. Summary This article presented a review of the common types of pneumatic valves, their configurations, and the key specifications that define these valves. For information on other topics, consult our additional guides or visit the Thomas Supplier Discovery Platform where you can locate potential sources of supply for over 70,000 different product and service categories. Sources: http://ingersollrand.jp https://www.ekci.com/ https://www.ipolymer.com/blog/common-pneumatic-valve-types-for-engineers/ https://www.machinedesign.com/mechanical-motion-systems/pneumatics/article/21834670/the-basics-of-pneumatic-control-valves https://tameson.com/52-way-and-42-way-pneumatic-valve.html
Дата Публикации: 02-11-22
Choosing Between Nonstick and Stainless Steel Cookware
Описание: Choosing Between Nonstick and Stainless Steel Cookware When shopping for cookware, people often wonder if they should opt for nonstick cookware or regular uncoated stainless steel. There's much to consider when selecting new pots and pans (even eco-friendly cookware is an option), so it's a good idea to understand the pros and cons to both varieties. It's mostly a matter of personal preference—keep the foods you frequently cook in mind so you can select the best pans for the job. While you can purchase almost any type of cookware online, if you're new to the process, it's best to go to a store. You'll want to feel, lift, and inspect the quality of many different pans. It's also helpful to see the pans in person in order to gauge the circumference of the cookware—sometimes online product photos do not give you a size scale for reference. Nonstick Nonstick cookware is easy to use and clean, as the slick coating helps to keep food from sticking, and it's easy to clean afterward. Health-conscious cooks like that they can use a lot less oil than they would with uncoated cookware. That helpful cooking surface also carries some potential risks. Certain scientists, environmentalists, and consumer advocacy groups have concerns about the chemicals used to make many of the nonstick coatings on the market, such as PTFE (most commonly known as Teflon). The chemical of most concern is PFOA. Fortunately, The Environmental Protection Agency asked major chemical manufacturers to phase out the use of PFOA, and Teflon has been PFOA-free since 2013. Using nonstick cookware will not expose you to PFOA, as the chemical is only in evidence in the manufacturing process and does not end up in the finished press non stick cookware. Exposing nonstick pans to very high temperatures will, however, release other potentially toxic chemicals into the air, so if you use nonstick pans, take precautions: Never heat a pan empty on a burner. Keep your burner on medium or low. Throw out a pan if its coating is starting to chip or flake. Lastly, nonstick pans simply can't achieve the searing and browning effect that an uncoated stainless steel pan does. Instead, food more or less steams in its own juices. You can also find more eco-friendly nonstick finishes on the market, such as the ceramic coating on Bialetti cookware. Stainless Steel Uncoated stainless pans do a great job at producing that beautiful and delicious browning (called the maillard reaction). They're more durable since there's not a coating to be concerned about protecting. As long as the handles are made of heatproof material, they're usually oven-safe. The drawback is that burnt-on food can require some elbow grease to get off (try an abrasive cleanser like Bon Ami or Barkeeper's Friend). What Should I Get? Buy one or two nonstick skillets for cooking eggs, pancakes, and other foods that are known to stick to a pan, but invest in high-quality uncoated stainless steel for the rest of your cookware, such as fry pan, and look at eco-friendly cookware selections too. For instance, there's no need for a nonstick coating in saucepans or pots, where the contents are mostly liquid. Spending each morning at the kitchen sink scraping at the charred remains of breakfast gets tedious after a while. Forged Non-stick cookware may seem like an appealing alternative — but is it safe? Usually when people inquire about the safety of their non-stick cookware set, they're talking about the brand Teflon, said Suzanne Fenton, a reproductive endocrinologist at the National Institutes of Environmental Health Sciences in North Carolina. Also known as polytertrafluoroethylene (PTFE), this clear plastic is used to coat metal pots and pans, giving them a waxy, easy-to-clean surface — and for decades, scientists have debated whether it's safe for cooking. Experts tend to agree that Teflon itself isn't a problem. The coating itself is considered non-toxic. Even if you ingest small flakes of it, it passes right through you. But some experts are concerned about what happens when Teflon gets too hot. "When pans are overheated, that PTFE coating begins to disintegrate," Fenton told Live Science. As Teflon breaks down, it releases a host of toxic gases. In rare instances, breathing in these chemical fumes can cause polymer fume fever, a condition characterized by a high fever, shortness of breath and weakness. These gases also deadly to birds — lightbulbs coated in Teflon have wiped out poultry houses. Of particular concern is perfluorooctanoic acid (PFOA), one of the chemicals released when Teflon pans heat up. Long-term exposure to PFOA is linked to a host of conditions from cancer to thyroid disease, Fenton said.
Дата Публикации: 02-11-22
Hot Rolled vs Cold Rolled Steel
Описание: Hot Rolled vs Cold Rolled Steel Steel comes in many grades, specifications, shapes, and finishes—the World Steel Association lists over 3,500 different grades of steel, each with unique properties. The various types mean that steel can by widely used in infrastructure, appliances, vehicles, wind turbines, and many more applications. Optimizing steel's properties for each application goes beyond changing the chemical composition, however. The manufacturing processing of steel can also have a significant impact on steel products—even when the grades and specifications are the same. One key distinction among pre-fabricated steel products is the difference between hot rolled and cold rolled steel. What's the difference between hot rolled and cold rolled steel? It's important to note that the main difference between hot rolled and cold rolled steel is one of process. "Hot rolling" refers to processing done with heat. "Cold rolling" refers to processes done at or near room temperature. Although these techniques affect overall performance and application, they should not be confused with formal specifications and grades of steel, which relate to metallurgical composition and performance ratings. Steels of different grades and specifications can be either hot rolled or cold rolled—including both basic carbon steels and other alloy steels. It may seem obvious, but some types of steel are better suited for certain applications. Knowing which to use can help avoid over-spending on raw materials. It can also save time and money on additional processing. Understanding the differences between hot and cold steel is integral to choosing one over the other. Hot rolled steel Hot rolled steel is steel that has been roll-pressed at very high temperatures. Hot rolled steel is steel that has been roll-pressed at very high temperatures—over 1,700?F, which is above the re-crystallization temperature for most steels. This makes the steel easier to form, and resulting in products that are easier to work with. To process hot rolled steel, manufacturers first start with a large, rectangular length of metal, called a billet. The billet is heated and then sent for pre-processing, where it is flattened into a large roll. From there, it is kept at a high temperature and run through a series of rollers to achieve its finished dimensions. The white-hot strands of steel are pushed through the rollers at high speeds. For steel sheet, rolled steel is spun into coils and left to cool. For other forms, such as bars or alloy steel plates, materials are sectioned and packaged. Steel shrinks slightly as it cools. Since hot rolled steel is cooled after processing, there is less control over its final shape, making it less suitable for precision applications. Hot rolled steel is often used in applications where minutely specific dimensions aren't crucial. Railroad tracks and construction projects often use hot rolled steel. Hot rolled steel can often be identified by the following characteristics: A scaled surface—a remnant of cooling from extreme temperatures Slightly rounded edges and corners for bar and weathering steal plate products (due to shrinkage and less precise finishing) Slight distortions, where cooling may result in slightly trapezoidal forms, as opposed to perfectly squared angles What are the benefits of hot rolled steel? Hot rolled steel typically requires much less processing than cold rolled steel sheet, which makes it a lot cheaper. Because hot rolled steel is allowed to cool at room temperature, it's essentially normalized—meaning it's free from internal stresses that can arise from quenching or work-hardening processes. Hot rolled steel is ideal where dimensional tolerances aren't as important as overall material strength, and where surface finish isn't a key concern. Where surface finish is a concern, scaling can be removed by grinding, sand blasting, or acid-bath pickling. Once scaling has been removed, various brush or mirror finishes can also be applied. Descaled steel also offers a better surface for painting and other surface coatings. Cold rolled steel Cold worked steels are typically harder and stronger than standard hot rolled steels. Cold rolled steel is essentially hot rolled steel that has been through further processing. Once hot rolled steel has cooled, it is then re-rolled at room temperature to achieve more exact dimensions and better surface qualities. Cold "rolled" steel is often used to describe a range of finishing processes, though technically "cold rolled" applies only to galvanized sheets that undergo compression between rollers. Steel forms that are pulled, such as bars or tubes, are "drawn," not rolled. Other cold finishing processes include turning, grinding, and polishing—each of which is used to modify existing hot rolled stock into more refined products. Cold rolled steel can often be identified by the following characteristics: Better, more finished surfaces with closer tolerances Smooth surfaces that are often oily to the touch Bars are true and square, and often have well-defined edges and corners Tubes have better concentric uniformity and straightness What are the benefits of cold rolled steel? With better surface characteristics than hot rolled steel, it's no surprise that cold rolled steel is often used for more technically precise applications, or where aesthetics are important. But due to the additional processing for cold finished products, they come at a higher price. In terms of physical characteristics, cold rolled steels are typically harder and stronger than standard hot rolled steels. As the metal is shaped at the lower temperatures, the steel's hardness, resistance against tension breaking, and resistance against deformation are all increased due to work hardening. These additional treatments, however, can also create internal stress within the material. This can cause unpredictable warping if the steel is not stress relieved prior to cutting, grinding, or welding. Manufacturing and product design Depending on what you're looking to build, different materials each have their own benefits and drawbacks. For run-of-the-mill projects or one-off productions, steel materials can provide the building blocks for any structural configuration imaginable.
Дата Публикации: 02-11-22
An analysis of Road Rollers – Types, Attachments, and Uses
Описание: An analysis of Road Rollers – Types, Attachments, and Uses A road roller is a compactor type engineering vehicle, which is used to compact soil, gravel, concrete, or asphalt in the construction of roads and foundations. Also, road rollers are used in landfills and agriculture. The rolling process ensures that foundations are compacted thoroughly so the materials are compact, and do not come loose. Rollers are equipped with basic features such as diesel engine, canopy to protect the driver, drum(s), which can be a vibratory smooth drum or a static smooth drum, tires, a compaction meter to measure the level of compaction and a water system. An analysis of the Use of road rollers Road rollers are iconic in the construction industry. In history, they started as simple stone cylinders being pulled by people to flatten the earth a bit, soon they made animals pull large stone cylinders or wooden planks as a means to flatten the earth. And then when the age of metal came, the rollers finally came into play. This piece of heavy equipment is one of the most common machines to find in construction sites, mainly because they are mostly used at the beginning stages when the foundation of the building is being built. A road roller is a compaction vehicle used to compact soil, gravel, asphalt, crushed stone sub-base layer or some other site surface material. Rollers are most often used for road construction or for creating compact foundations for large areas although they can also be used in areas as diverse as on landfill sites or agricultural projects.The primary use for rollers is to crushing equipment, knead or vibrate loose materials by applying direct pressure. The rolling process is used to compact loosely bound foundation materials, so they remain compacted and do not come loose. Road rollers use the weight of the vehicle to compress the surface being rolled or use mechanical advantage (vibrating). Initial compaction of the substrate on a road project is done using a padfoot drum roller, which achieves higher compaction density due to the pads having less surface area. Rollers are also used in landfill compaction. Such compactors typically have padfoot or "sheep's foot" drums, and do not achieve a smooth surface. The pads aid in compression, due to the smaller area contacting the ground. Roller types Road rollers are essential for those thinking about maximizing their output. There is a tremendous amount of stress that is put on the system and it's important to start with a reliable solution. With the help of a high-grade road roller, it becomes easier than ever before to make sure proper results are found. This is why people love the idea of a great road roller. Discussed below are the various types of road rollers. Single drum roller A single drum roller is a heavy duty piece of machinery. The front has a giant drum while the back has special tires. These tires are sturdier and able to prevent most flats. You need these heavy-duty tires when you work on construction sites and roads.On the single drum roller, the driver sits in the middle section. This part is called the cab. It sits high, giving the driver a great view of the nearby area. The worker can see the places where they will use the roller. Double drum roller The main difference with the double drum roller is that it lacks tires. That's good or bad, depending on your job.A double drum roller can smooth objects in front of and behind the driver at the same time. The trade-off is that the drums move the roller while flattening items in the surrounding area.For this reason, double drum rollers don't have the traction of single drum units. You won't use these vehicles for specialized work. They operate best on flat services or ones with gradual grading. Cylinder Roller These are the most common rollers used today. They have the traditional cylinder drum and are the most basic type of road roller. Most of these are just single drum rollers, though there are often designs that make use of two drums. They are also known as smooth wheel loader rollers. These type of road rollers are mostly used for consolidating stone or other similar materials into flat land. They are believed to work best when you also use surface dressings to create an even smoother, flatter surface. Vibratory Roller Visually, a vibratory roller isn't much different from the cylinder roller. What differentiates it is an internal eccentric shaft that causes the wheel drums to vibrate. Its vibratory function enhances its functionalities by a lot. This makes them more commonly used in applications with granular base layers. Sometimes, they're also used in laying asphalt in highway construction. The vibratory features help reduce the space between particles in the materials being compacted, creating denser layers to add greater depth to the foundation. The vibrations also cause the particles to lie closer together as they're pushed into place by the oscillations from it. Rubber-Tyred Roller These types of rollers move away from the typical wheel drums and instead have several rows of closely spaced pneumatic tires both in front and at the back of the machine. These tires are also staggered to exert compacting pressure across the full width of the machine These kinds of rollers are best used on soft materials and loosely compacted soils. That being said, they are also found in highway construction, particularly for when they start smoothing bitumen on some roadworks. Tamping Roller These types of road rollers are unique when it comes to their wheel drums. These are studded with lugs that are usually rectangular in shape and arranged in a rather hexagonal pattern. Some designed have different shaped lugs, though, in actuality, their shape isn't that important. These tamping rollers are also called sheep foot rollers and are normally used in projects that have to work with heavy soils such as clay. This is because the overall surface area of the drum that's in contact with the soil at any one point in time is projected to be around 8 to 12%. Parts and attachments of a road roller The rollers parts and attachments vary from design to design with added modifications, however the most constant ones are- On some machines, the drums may be filled with water on site to achieve the desired weight. When empty, the lighter machine is easier and cheaper to transport between work sites. On pneumatic tyre rollers the body may be ballasted with water or sand, or for extra compaction wet sand is used. Modern tyre rollers may be filled with steel ballast, which gives a more even balance for better compaction. Additional compaction may be achieved by vibrating the roller drums, allowing a small, light machine to perform as well as a much heavier one. Vibration is typically produced by a free-spinning hydrostatic roller motor grader inside the drum to whose shaft an eccentric weight has been attached. Some rollers have a second weight that can be rotated relative to the main weight, to adjust the vibration amplitude and thus the compacting force. Water lubrication may be provided to the drum surface from on-board "sprinkler tanks" to prevent hot asphalt sticking to the drum. Hydraulic transmissions permit greater design flexibility. While early examples used direct mechanical drives, hydraulics reduce the number of moving parts exposed to contamination and allows the drum to be driven, providing extra traction on inclines. Human-propelled rollers may only have a single roller drum. Self-propelled rollers may have two drums, mounted one in front of the other (format known as "duplex"), or three rolls, or just one, with the back rollers replaced with threaded pneumatic tyres for increased traction. Conclusion There are multiple requirements associated with a road roller and the operator needs to get through the project easily. With this in mind, the road roller is great as it can handle everything the project demands. There is a sense of power that comes along with a great road roller and it's important to invest in one as soon as possible. The right road roller can deliver on all expectations and continues to maximize the work that's being done. There is nothing better than taking a high-grade road roller and making sure the power is consist.
Дата Публикации: 02-11-22
Benefits Of Listening To Audio Books
Описание: Benefits Of Listening To Audio Books Along with writing and math, reading is an essential skill for your child to develop for school success. Unfortunately, many children do not have an interest in regular reading. Parents are discovering audio books, with reading accompanied by music and sound effects not only offer ease of use, but often also involve children in a way simply reading a book cannot. There are many benefits to listening to literature with audio books for children. Some of them are: Audio books help develop your child's imagination because your child must picture the scenes and characters described. They promote a better vocabulary and understanding of words, their meaning, and how they work. You child may be encouraged to read the book upon which the audio is based. Audio books help children cope better with long journeys as they can be played in the car or even on trains and buses. Children who find it hard to sleep alone may find it easier to do so if they listen to stories when they go to bed in order to relax. Audio books introduce new genres of literature to your child, opening up a completely new world of sound books. Great for developing listening skills because they require quiet concentration. Hearing books read aloud teaches an appreciation of phrasing. Authors write some books to be read aloud, and listening to them is more authentic than reading them. Audio books help your child understand complex language. Listening to a book read helps your child learn punctuation, enunciation, and emphasis, all of which bring out the meaning of a text and improve speaking and writing skills. Children who listen to audio books learn to understand language above their reading level, and learn new words and advanced constructs. Audio books are excellent tools for dyslexics and children with other reading disabilities. If your child has an attention deficit disorder, listening is more distraction-free than reading. Your child can listen to audio books anywhere. Your child may be motivated to read more by an author they've been introduced to through an audiobook, How to Choose an Audio Book for Your Child Make sure you preview the audio books you choose for your child, considering the following: Is the narrator's voice pleasant, easy to understand, and appropriate for the subject matter? If there is music, is it in keeping with the text or is it too loud, detracting from the words? Do the sound effects enhance the story? If the audio book is presented by a cast are their voices appropriate for the ages and personalities of the characters they represent? As your child hears an audio book, they enter a journey where reading seems friendlier and more approachable. Your young reader listening to an audio book is more apt to establish a pattern of concentrating on the sounds of words without being interrupted by personal reading obstacles. Although nothing replaces a parent sharing a sound module for book by one-on-one reading, audio children music books provide an excellent alternative. They help a child develop reading skills and give them hours of enjoyment. For more information about children's beds, children's bedroom furniture, as well as ideal storage solutions, get in touch with our expert team today.
Дата Публикации: 02-11-22
Is Polyurethane Environmentally Friendly?
Описание: Is Polyurethane Environmentally Friendly? People are more focused on products and technologies that are friendly to the environment than ever. With climate change at the front of many political debates, people want to be sure the products they're using aren't harmful to the environment and don't pose any health risks when using. One industry that takes a lot of flack from those concerned about the environment is the plastics industry. That is because of its reliance on fossil fuels and those mountains of plastic waste all over the planet. But not all plastics are created equal, and in this piece, we look at polyurethane and answer the question: how environmentally friendly is it? Polyurethane vs Plastic or First, let's get the answer out of the way and then look into the specifics. Yes, polyurethane, like PU sheet is inherently more eco-friendly than most other plastics. It also doesn't contain any chemicals that interfere with endocrine and hormone systems, nor does it contribute to PH change in soil or water. But what about all that plastic waste we see in photos almost everyday? Note that most of the plastics in the shocking photos are thermoplastics, which account for over 95% of the waste seen in the oceans. In contrast: polyurethane plastics account for less than 2%. Stated by urethane manufacturers, one reason for this low level of waste is that polyurethane lasts far longer than most thermoplastics. This means industries that rely on polyurethane products aren't throwing those products out as often because of wear. Another advantage is that there are a variety of directions one can take to recycle polyurethane parts back into prepolymer constituents from which they were made. Also, scientists use microorganisms to break downcast urethane products, and once in the environment, casting polyurethane prepolymer aren't toxic to the environment as they break down. These facts make polyurethane more environmentally friendly plastic. The manufacturing process Okay, so polyurethane itself is better for the environment, but what about the process of making this plastic? Isn't it just as bad for climate change and the environment as other plastic manufacturing? Many polyurethane manufacturers work hard to minimize the impact on the environment by optimizing the manufacturing process and becoming more energy efficient. Also, today's polyurethane manufacturers like Sabic continue to work closely with polymer-machine producers to make casting systems that reduce the amount of waste coming from the manufacturing process. Note that advancements in 3D printing and simulations of how materials flow through molds mean that engineers can design molding systems that drastically reduce the amount of waste material produced. Being able to reclaim parts and re-use existing metal components means that you can refurbish polyurethane cast parts, which is not as easy to do with other products. Some metal components can last virtually a lifetime as long as the urethane section is upgraded when needed. So, for instance, a wheel hub may have a lifespan of over 30 years, which benefits the environment by not having to manufacture parts as often. Lastly, the polyurethane industry as a whole continues to work towards improving the end-of-life phase of their products to increase sustainability. We can see that the industry is making significant progress towards increasing the amount of material that's recovered and recycled and reducing what goes into landfills. How polyurethane helps the environment While opponents point out that polyurethane manufacturing uses fossil fuels such as oil, which contributes to climate change, what they fail to mention is how the polyurethane products themselves fight against climate change and benefit the environment. First: Polyurethane products, such as hot casting polyurethane prepolymer, are effective insulators, which improves the energy efficiency of buildings, thus reducing the energy required to heat and cool, and consequently lowering carbon emissions. Second: polyurethane products make vehicles more fuel-efficient because they're lighter than other materials. Another example where polyurethane benefits the environment is in the use of domestic refrigerators which use polyurethane as an insulator to increase energy efficiency. Improving energy efficiency goes a long way to reducing carbon emissions and the effects those have on climate change. Lastly, in many places, polyurethane waste is used to generate power for solid waste incineration thus reducing the need for fossil fuels. Polyurethane is an extremely versatile material and is used in a variety of industries and applications from automotive to furniture, bedding, appliances, construction, and more. What makes polyurethane so attractive are its longevity and energy efficiency, both of which have positive impacts on the environment and the effects of climate change. Also, what does end up going to waste is non-toxic and won't damage soil or water. As the polyurethane industry moves forward, it continually develops new ways to reduce the amount of waste it produces and to increase the energy efficiency of the manufacturing process. Properties of casting polyurethane elastomer Technical characteristics of polyurethane make it an indispensable structural material in many industries where products must have high resistance, wear resistance, resistance to aggressive environmental influences. The density of the polyurethane depends on its type, indicators can be in the range of 30-300 kg/m3. Polyurethane has a wide range of hardness from very soft, like a gel bicycle seat (~25 Shore OO), to very hard, like a bowling ball (~75 Shore D). But the sweet spot for many of its performance properties occurs from 55 Shore A to 75 Shore D. Polyurethane has an extensive operating temperature range, from -60 to +80 °C, short-term use at + 120-140 °C is possible without loss of technical characteristics. Polyurethane has high elasticity with high hardness of the material, its strength indicators reach up to 50MPa. It can stretch up to 650% without damage. Polyurethane does not conduct electricity. Polyurethane has a low weight, which gives an alternative to using products with a lower weight. Ozone resistance is also a definite plus, polyurethane does not collapse under the influence of ozone, such as rubber. Polyurethane is highly resistant to acids, oils, solvents. The main competitors of polyurethane are rubber, plastic and metal. Compared to rubber, polyurethane has higher wear resistance and elasticity, is not susceptible to oils, gets dirty less, ages more slowly, takes shape more quickly after deformation and better tolerates mechanical stress. If we compare polyurethane with metal, it is obviously more flexible, has less weight, does not conduct electricity and is less susceptible to abrasives. Polyurethane is also much cheaper to manufacture and maintain, mechanisms equipped with parts from this material create less noise. All this affects the quality and cost of the final product. In comparison with plastic, polyurethane shows better results at high and low temperatures, it is more flexible, does not crack under shock and other mechanical stress. Choosing a reliable urethane product manufacturer can be difficult, but TPC Inc. team makes it easier. If you have any questions about urethane and polyurethane solutions, don't hesitate to get in touch with them here.
Дата Публикации: 02-11-22
Everything You Need To Know About Injection Molding
Описание: Everything You Need To Know About Injection Molding What is Injection Molding: Injection Molding is a manufacturing process for producing parts in large volume. It is most typically used in mass-production processes where the same part is being created thousands or even millions of times in succession. Why Use Injection Molding: The principal advantage of injection molding is the ability to scale production en masse. Once the initial costs have been paid the price per unit during injection molded manufacturing is extremely low. The price also tends to drop drastically as more parts are produced. Other advantages include the following: Injection Molding produces low scrap rates relative to traditional manufacturing processes like CNC rubber machining which cut away substantial percentages of an original plastic block or sheet. This however can be a negative relative to additive manufacturing processes like 3D printing that have even lower scrap rates. Note: waste plastic from injection molding manufacturing typically comes consistently from four areas: The sprue The runners The gate locations Any overflow material that leaks out of the part cavity itself (a condition called "flash"). A sprue is simply the channel that guides molten plastic from the nozzle of the injection molding machine to the entry point for the entire rubber injection machine tool. It is a separate part from the mold tool itself. A runner is a system of channels that meet up with the sprue, typically within or as part of the mold tool, that guides the molten plastic into the part cavities within the mold tool. There are two principal categories of runners (hot and cold) which you can read about here. Lastly, the gate is the part of the channel after the runner that leads directly into the part cavity. After an injection mold cycle (typically only seconds long) the entirety of the molten plastic will cool leaving solid plastic in the sprue, runners, gates, part cavities themselves, as well as a little bit of overflow potentially on the edges of the parts (if the seal isn't 100% right). Thermoset material, such as an epoxy resin that cures once exposed to air, is a material that cures and would burn after curing if one attempt is made to melt it. Thermoplastic material by contrast, is a plastic material that can be melted, cool and solidify, and then be melted again without burning. With thermoplastic materials the material can be recycled are used again. Sometimes this happens right on the factory floor. They grind up the sprues/runners and any reject parts. Then they add that material back into the raw material that goes into the injection molding press. This material is referred to as "re-grind". Typically, quality control departments will limit the amount of regrind that is allowed to be placed back into the press. (Some performance properties of the plastic can degrade as it is molded over and over). Or, if they have a lot of it, a factory can sell this re-grind to some other factory who can use it. Typically regrind material is used for low-quality parts that don't need high performance properties. Injection Molding is very repeatable. That is, the second part you produce is going to be practically identical to the first one etc. This is a wonderful characteristic when trying to produce brand consistency and part reliability in high volume production.
Дата Публикации: 02-11-22
WHY CHOOSE WIRE MESH
Описание: WHY CHOOSE WIRE MESH Why Choose Banker Architectural Wire Mesh for Architecture? As an extremely versatile material, mesh is ever-growing in popularity for use within a number of applications. Not only customizable, durable and sustainable, architectural wire mesh is also available in thousands of patterns, the perfect medium to satisfy any project, no matter the function or aesthetic. We offer a wide variety of woven wire mesh as well as a selection of ornamental welded wire mesh for architectural applications. With over 100 years of experience in wire mesh manufacturing, Banker Wire has the knowledge and product selection to achieve any budget or visual goal. From parking garages to millwork and cladding, from space dividers and displays to fences and enclosures, wire mesh's multifaceted nature establishes it as a favored material for any project, whether functional, detail-oriented, aesthetic, creative, commercial or ornamental. Wire Mesh in Architectural Railings Railings are an important element of any architectural project, more specifically, railing infill. Infill panels work in tandem with a chosen garden railing system. They are used as protective barriers and methods to guide people in high traffic areas such as stadiums, schools, entertainment venues, and in many more applications. Not only are railing infill panels functional, but they contribute to the overall aesthetic of their surroundings. Able to conceal or give high levels of transparency while maintaining a simple or highly decorative design, wire mesh as railing infill is extremely versatile and practical. Architectural mesh is the perfect choice for stair railing infill, whether the project is commercial or residential in nature. Wire mesh is often specified as infill panels because it offers visibility, safety, and aesthetic potential. Banker Wire offers a wide range of alloys, which means there is always an option to suit the project, no matter the budget, function, and aesthetic. With a variety of patterns, from simple to highly elaborate, architectural wire mesh is a unique addition to both traditionally styled and contemporary balcony railings. Because of its strength and durability, Banker Wire wire mesh used as railing infill panels are highly functional and can either blend seamlessly with the surroundings or make a bold creative statement. Restoration Projects Utilizing Wire Mesh Restoration projects preserve the invaluable history of things like historic buildings, residences, automobiles, and much more. Attention to detail is extremely important when restoring any piece, especially when attempting historical accuracy. From the type of wood used, to the particular pattern of a vehicle's grille, restoration hobbyists and specialists know that quality and detail matters in every project. As a wire mesh manufacturer with over 100 years of experience, Banker Wire is no stranger to how wire mesh has been used throughout history. Wire mesh is a timeless decorative material and, since its invention, it has grown to include an abundance of raw material and pattern choices. The wide range of densities and patterns that have been manufactured over the years has made wire mesh the economical and aesthetic choice for a variety of applications and industries. Automotive grilles, radiant water heat cabinets, and ornamental railing are a few popular examples of how wire mesh found a useful and decorative function throughout the 19th and 20th centuries. Using Architectural Mesh in Steel Fences & Enclosures Iron Fences and enclosures often have strict regulations that require exact specifications to meet code regulations while also maintaining affordability. Pools, playgrounds, rail yards, sports venues, and many other types of locations utilize fences or enclosures for safety and security. Lately, designers have been looking to maintain function while using fence materials that are more ornamental, such as wire mesh. Banker Wire's architectural wire mesh is extremely versatile for fencing and enclosure projects. Thousands of patterns are available in a multitude of sizes, scales, and raw materials to fit any requirement from simple to complex. Any pattern or wire spacing can be customized to fit your project. Wire mesh can either allow for openness and uninterrupted sight lines, or it can obscure and seclude areas, depending on the needs of the designer. Complete versatility combined with a wide range of patterns to fit every budget, wire mesh for aluminum fences or enclosures is a logical, cost-effective choice. Applications for Millwork & Cladding Traditionally, millwork is a term that relates to any exposed wood in a finished building, such as cabinetry. While custom wood cabinets are beautiful, from time to time, they may need a little extra ornamentation to fit with the aesthetic of their surrounding area. The combination of metal against wood draws out the beauty and warmth of wood with the coolness of metal. Architectural wire mesh used as cladding, also known as surfacing, utilizes very similar techniques to add texture and intrigue to elevator cabs, office lobbies, furniture, and many other applications. Wire mesh can cover an entire surface, or just part of one to create any look the designer desires. Banker Wire prides itself on being a versatile architectural mesh manufacturer for many different clients and projects all around the world. Woven wire mesh as part of millwork or cladding makes a striking impression in commercial and residential spaces. The fundamental composition of ornamental wire mesh patterns has a creative fluidity to it that allows the wire mesh to fit both bold and delicate arrangements. In addition, wire mesh is a robust material that can withstand the rigors of high traffic areas. With such wide variety of patterns, Banker Wire can find a design to complement any space, both modern and traditional. Using Wire Mesh Fence in Parking Garages Parking garages are a necessity in urban design and need to be secure, well-ventilated, and economical to the best of the designer's ability. However, some designs call for elaborate and decorative elements that can come in many different forms. From utilitarian to a unique aesthetic, parking garages come in all varieties, and wire mesh is oftentimes the material of choice. For parking garages, Banker Wire's architectural wire mesh serves as security as well as improving ventilation. When specified to do so, wire mesh can aid in protecting the contents of parking garages while allowing air and light to flow freely through the space. Banker Wire can customize any wire mesh pattern to fit the exact specifications of the architect. Architectural mesh can provide not just the functionality that parking garages require, but wire mesh can also deliver a beautiful aesthetic to match any vision. No matter the size of the project specifications, Banker Wire's wide range of wire mesh patterns and customization options make for the perfect choice. Applications for Canopies In many architectural applications, canopies are used to provide varying levels of shade and shelter from weather conditions like rain, hail, and snow. Architectural canopies can also be purely aesthetic, giving a sense of luxury or artistry to a pedestrian area. From fabric to metal, a canopy can combine many different materials to suit the intent of its designer. From purely aesthetic to functional, architectural wire mesh can make a special addition to any canopy design. Architectural wire mesh is an excellent choice for canopies, and Banker Wire has developed a vast range of patterns to suit almost any project's requirement. With wire mesh as part of a canopy, pedestrians are given protection from the sun while still allowing light to pass through. What's more, interesting shade patterns develop as a result of light filtering through the mesh, creating points of interest for those who find shade beneath the canopy. Banker Wire architectural wire mesh comes in a wide range of densities that can be customized to suit the designer's concept. With its extensive array of architectural mesh designs, Banker Wire can easily find a pattern that complements the aesthetic of any project.
Дата Публикации: 02-11-22