What is amino acids and vitamins

Description: What is amino acids and vitamins     Amino acids function: building blocks of proteins     Proteins are of primary importance to the continuing functioning of life on Earth. Proteins catalyze the vast majority of chemical reactions that occur in the cell. They provide many of the structural elements of a cell, and they help to bind cells together into tissues. Some proteins act as contractile elements to make movement possible. Others are responsible for the transport of vital materials from the outside of the cell (“extracellular”) to its inside (“intracellular”). Proteins, in the form of antibodies, protect animals from disease and, in the form of interferon, mount an intracellular attack against viruses that have eluded destruction by the antibodies and other immune system defenses. Many hormones are proteins. Last but certainly not least, proteins control the activity of genes (“gene expression”).     This plethora of vital tasks is reflected in the incredible spectrum of known proteins that vary markedly in their overall size, shape, and charge. By the end of the 19th century, scientists appreciated that, although there exist many different kinds of proteins in nature, all proteins upon their hydrolysis yield a class of simpler compounds, the building blocks of proteins, called amino acids. The simplest amino acid is called glycine, named for its sweet taste (glyco, “sugar”). It was one of the first amino acids to be identified, having been isolated from the protein gelatin in 1820. In the mid-1950s scientists involved in elucidating the relationship between proteins and genes agreed that 20 amino acids (called standard or common amino acids) were to be considered the essential building blocks of all proteins. The last of these to be discovered, threonine, had been identified in 1935.     Chirality     All the amino acids but glycine are chiral molecules. That is, they exist in two optically active asymmetric forms (called enantiomers) that are the mirror images of each other. (This property is conceptually similar to the spatial relationship of the left hand to the right hand.) One enantiomer is designated D and the other L. It is important to note that the amino acids found in proteins almost always possess only the L-configuration. This reflects the fact that the enzymes responsible for protein synthesis have evolved to utilize only the L-enantiomers. Reflecting this near universality, the prefix L is usually omitted. Some D-amino acids are found in microorganisms, particularly in the cell walls of bacteria and in several of the antibiotics. However, these are not synthesized in the ribosome.     Acid-base properties     Another important feature of free amino acids is the existence of both a basic and an acidic group at the α-carbon. Compounds such as amino acids that can act as either an acid or a base are called amphoteric. The basic amino group typically has a pKa between 9 and 10, while the acidic α-carboxyl group has a pKa that is usually close to 2 (a very low value for carboxyls). The pKa of a group is the pH value at which the concentration of the protonated group equals that of the unprotonated group. Thus, at physiological pH (about 7–7.4), the free amino acids exist largely as dipolar ions or “zwitterions” (German for “hybrid ions”; a zwitterion carries an equal number of positively and negatively charged groups). Any free amino acid and likewise any protein will, at some specific pH, exist in the form of a zwitterion. That is, all amino acids and all proteins, when subjected to changes in pH, pass through a state at which there is an equal number of positive and negative charges on the molecule. The pH at which this occurs is known as the isoelectric point (or isoelectric pH) and is denoted as pI. When dissolved in water, all amino acids and all proteins are present predominantly in their isoelectric form. Stated another way, there is a pH (the isoelectric point) at which the molecule has a net zero charge (equal number of positive and negative charges), but there is no pH at which the molecule has an absolute zero charge (complete absence of positive and negative charges). That is, amino acids and proteins are always in the form of ions; they always carry charged groups. This fact is vitally important in considering further the biochemistry of amino acids and proteins.     What are vitamins, and how do they work?     Vitamins are organic compounds that people need in small quantities. Most vitamins need to come from food because the body either does not produce them or produces very little. Each organism has different vitamin requirements. For example, humans need to get vitamin C from their diets — while dogs can produce all the vitamin C that they need.     For humans, vitamin D is not available in large enough quantities in food. The human body synthesizes the vitamin when exposed to sunlight, and this is the best source of vitamin D. Different vitamins play different roles in the body, and a person requires a different amount of each vitamin to stay healthy.     This article explains what vitamins are, what they do, and which foods are good sources. Follow the links in blue below for more information about each vitamin. Vitamins are organic substances present in minute amounts in natural foodstuffs. Having too little of any particular vitamin may increase the risk of developing certain health issues. A vitamin is an organic compound, which means that it contains carbon. It is also an essential nutrient that the body may need to get from food.     Fat-soluble vitamins     Vitamins A, D, E, and K are fat-soluble. The body storesTrusted Source fat-soluble vitamins in fatty tissue and the liver, and reserves of these vitamins can stay in the body for days and sometimes months. Dietary fats help the body absorb fat-soluble vitamins through the intestinal tract.     Water-soluble vitamins     Water-soluble vitamins do not stayTrusted Source in the body for long and cannot be stored. They leave the body via the urine. Because of this, people need a more regular supply of water-soluble vitamins than fat-soluble ones.

Publish Date: 2021/09/05

What are Moisture Analyzers and How do They Work?

Description: What are Moisture Analyzers and How do They Work?     A moisture balance, also called a moisture analyzer, measures the amount of moisture in a substance. This is particularly helpful in food processing lab consumables as the amount of moisture can be an indicator of freshness and quality for some foods. These analyzers are also commonly used in environmental, pharmaceutical, and materials science labs. There are several techniques that may be used to measure moisture. Some techniques used include measuring water vapor released following combustion of the sample, measuring the difference in weight after removal of moisture from the sample, and measuring the equilibrium of water vapor of the sample in a closed system. Some things to take into consideration when purchasing a moisture analytical balance include capacity, precision, speed, method of measurement, software, and whether the samples to be measured come in solid or liquid form.     Moisture analyzers, sometimes called “moisture balances”, are used to measure the moisture content in various types of samples including solids, liquids, and gases. Trace moisture in solids must be controlled for plastics, pharmaceuticals and heat treatment processes. Gas or liquid measurement applications include dry air, hydrocarbon processing, pure semiconductor gases, bulk pure gases, dielectric gases such as those in transformers and power plants, and natural gas pipeline transport.     Due to the slow pace of traditional and manual laboratory moisture testing methods, automated moisture analyzers have been developed and can reduce the time necessary for a test from hours to just a few minutes.     Moisture analyzers are utilized in different industries for many different purposes. They can be used in food industry to control the moisture. Excess amount of moisture in food may lead to staleness or bacterial growth. Furthermore, there are many food items which are sold by their weight; thus, it is important to make sure customers aren’t overpaying for water weight. On the other hand, too little moisture can reduce the calorie count or make the food dry. Moisture is an important factor affecting the consistency, taste, shelf appearance and many other factors in food.     Moisture analyzers, as industrial weighing scale, are also frequently used in quality control and other laboratories. Moisture analysis is used in many fields to determine the water content in crude oil, fuel, sewage sludge and many other chemicals, solids and liquids.     Most moisture analyzers have a computer interface to assist with the observation and analyse in the drying process and its effects on the sample. They have the capacity to save the tests in their memory to repeat frequent testing parameters without having to set them up over and over again to assist with the elimination of down time.     How moisture analyzers work     Moisture analyzers utilize Loss On Drying (LOD) method to measure moisture. In this method, the moisture analyzer weighs a sample, heats it up to dry it, and weighs it again once it’s dry. The weight after drying is subtracted from the weight before, so the loss of moisture is determined using the loss of mass.     The heat generating system can vary from analyzer to analyzer. Some moisture analyzers use halogen and some use infrared or glass-free metal heaters positioned above a precision electronic balance. Halogen moisture analyzers are quick, efficient and responsive. These types of moisture analyzers are ideal to use where there is no single setting that heats all samples evenly.     Density balances decide the density in liquid and solid materials as per the buoyancy method. Density balances are mainly electronic, maintain accuracy and beneficial to know the density in ceramics, glass, rubber, plastics, sintered metals and other non-metallic materials.     The method of density determination, like textile balance, is denoted by high veracity and quick results. Liquid Density is measured via the buoyancy test with the glass element. On the other hand, the density in solid materials is decided by using the weight and volume of a sample.     In Density Balances, the weighing unit determines the weight. The density of the Liquid must be ensured prior because the volume is obtained when the pressure of the sample is put in the liquid     The process of selecting chromatography sample vials for your laboratory can be complicated because there are many factors to consider as well as numerous options to choose from. This article offers guidance by providing an overview of chromatography vial options and how each can suit specific needs.     When choosing a chromatography vial, the product material is of paramount importance. Depending upon the use, either glass or plastic testing vials may be best. Begin by considering the facts and benefits regarding glass ultra clean vials.     Glass Vials     Glass vials are pure, meaning they have no traces of contaminants within their components, for example metal, which could potentially interfere with an experiment. Glass is also heat resistant, which is vital because glass chromatography vials may be heated to over 500 degrees Celsius. That makes glass vials a common choice for many labs.     Plastic Vials     Plastic vials have their own set of specifications and benefits. It is important to note that the type of plastic makes a difference in the storage vial and its uses. Plastic vials can be made of either polypropylene or poly methyl pentene (PMP). Polypropylene is the most popular plastic material available. To put it in perspective, the recyclable containers you store your dinner leftovers in are commonly made of this as well as the plastic lid on a box of Tic Tacs. Polypropylene vials have a heat resistance of up to 135 degrees Celsius, are translucent and are used commonly in chromatography experiments.     PMP has a higher heat resistance—up to 175 degrees Celsius—and is transparent, which increases visibility of the sample within the vial. Aside from scientific uses, PMP is used in the making of cookware, microwave components and even some windows.     Plastic vials provide the benefits of good chemical resistance, light weight construction, durability and affordability.

Publish Date: 2021/09/05

Why Get Home Security Cameras?

Description: Why Get Home Security Cameras?     Home security cameras keep watch over your home from both inside and outside, acting as an extra pair of eyes and ears to monitor your property. In this guide, we'll look at the benefits of installing indoor and outdoor security cameras, from their potential to deter criminals to other applications such as pet and baby monitors. We'll also explore the necessary and optional features of security cameras, as well as their drawbacks. Finally, we’ll discuss some of the other ways to protect your home if you’re not sure about installing cameras.     What Are the Benefits of Home Security Cameras?     Peace of mind is one of the main benefits of security cameras, whether you choose to install cameras that are wired or wireless. They can increase your home security by letting you check in on your property from wherever you are, see a live feed of your home on a smartphone or computer, and get immediate alerts of any unusual activity.     While the number of burglaries in the U.S. continued to decline recently, the value of the property stolen increased in 2018 to $2,799 (the most recent year for which this information is available). These studies indicate that although burglary rates are dropping, more valuable items are being stolen. This makes home security cameras an important tool in our home protection kit, as they can help with recovery as well as detection.     Security cameras are recognized as an excellent deterrent to criminals. The experts we spoke with don't recommend relying solely on cameras for security, saying a complete home security system is the best defense. However, cameras are still important. “If I had to choose, I would go with an alarm system over a camera system first,” says Jordan Frankel, vice president of security consulting firm Global Security Experts Inc. “But I do think cameras are a great addition, primarily because they're a psychological deterrence. A bad guy sees the camera and may skip your home and move on to an easier target.”     Research backs this up. A study of incarcerated burglars by the University of North Carolina at Charlotte’s Department of Criminal Justice and Criminology showed that indicators of increased security, such as outdoor surveillance cameras, were considered by most burglars when selecting a target.     Home security cameras aren’t just useful for policing your property; they’re also helpful for keeping an eye on children and pets when you can’t be there. A security camera with facial recognition by your front door can send you a push notification saying, “John is at the front door,” so you know your child is home safely. Two-way audio on indoor cameras can act as an intercom, allowing you to see and talk to your family when you’re not home.     For more on the benefits for home security cameras check out How to Buy Home Security Cameras and How Home Security Cameras Work.     What Are the Drawbacks of Home Security Cameras?     Privacy is a big concern when putting cameras around your home. “Whatever it records is technically on the internet forever,” says David VanWert, a home technology consultant and founder of VanWert Technology Designs Inc. “Once it's stored in the cloud, in theory, it never goes away.” But as VanWert points out, you likely already have a number of devices in your home with cameras that can record what you’re doing, such as smartphones and computers. There are steps you can take to minimize the security and privacy risks of installing security cameras, however. If you're concerned, consider only installing cameras on the outside of your home, and don’t put them in personal spaces such as bedrooms.     Liability can be another drawback. “If you;re just watching your own property, you’re probably fine,” says Jeff Welch, a former corrections officer and founder of Grab The Axe security consultants LLC. “But if your neighbor believes or has evidence that you have one pointed towards his bedroom window or front door, then you have an issue on your end for liability for their privacy.”     Also, if you record someone’s conversation without their knowledge – even on your own property – you could be breaking the law, depending on where you live. Denise Howell, an internet and technology lawyer, says that under federal law, as long as you’re a party to the conversation and you consent to it being recorded, it doesn’t matter what the other parties think. However, several states have two-party consent laws that make it illegal to record audio conversations without the consent of everyone involved. Plus, it’s almost always illegal to record a conversation if you’re not participating in it at all. A good rule of thumb is to let any visitors know when they are being recorded and consider posting notices on your property indicating it’s being surveilled by audio and video recording technology. Additionally, specific features such as facial recognition (found on Nest cameras) are illegal in some states. Check the applicable laws where you live.     Another drawback is that home security cameras can be costly. While their prices have come down a lot in recent years, to outfit your entire property with security cameras can cost thousands of dollars. Additionally, these high-value items on the outside of your house can be a target for theft themselves.     Are Home Security Cameras Good for Home Protection?     A home security camera system is an excellent tool for home protection, and it can work both as a deterrent and a recovery tool. Burglars are wary of properties with visible security cameras. Plus, if a crime does occur, security cameras can help gather evidence. From property damage to potentially identifying criminals who break in, if you capture the action on camera, you're more likely to be able to remedy it.     If you want to be able to identify cars, people, and other moving objects, it’s worth investing in a camera with super or ultra-high definition video (2K or 4K, respectively). This technology uses more pixels in the image, meaning you can zoom in to see more detail on license plates and identify more physical characteristics. An HD or full HD camera won’t get you that type of clarity, especially at night.     Ultimately, home security cameras work best to protect your property when they're integrated with a home security system. To save their batteries, wireless security cameras only start to record when they detect motion, which means they may not record everything you'd want them to. With a home security system, cameras, especially mini camera, can be set to start recording as soon as any part of the security system is triggered, such as a contact sensor, a glass-break sensor, or a motion sensor. This makes it more likely the cameras will record everything that’s happening on your property and not just the few seconds of motion that occurred right in front of them.     For more on home security systems, read our guide to Best Home Security Systems of 2021.     What Are the Most Important Home Security Camera Features?     First, decide whether you want your home security camera to record footage continuously or based on a trigger, such as motion. Recording continuously will make sure yo don't miss anything, but it will require a lot of Wi-Fi bandwidth and isn't suitable for battery-powered wire-free cameras. The footage should be stored either on the camera itself or on a cloud-based server where you can access it for a period of time. The camera also should alert you to motion by sending a notification to your smartphone or tablet and quickly deliver clear, good-quality video of the event. “Any camera that can record footage at full high definition or above is going to be good,” says VanWert. “Some can record at 4 and 5 megapixels, and then you’re talking about 4K resolution. It depends on what level of detail you're looking for, such as whether you want to be able to zoom in on your camera and see a license plate.”     The power source is another key feature of a security camera. If you're buying a wireless camera, look for one that's powered by batteries or AC (which means it plugs into a wall outlet). AC power is preferable but not always available where you want to install a camera. As a result, the ability to use both allows for maximum placement flexibility.     What Are Less Important Home Security Camera Features?     Continuous video recording, also called 24/7 recording, is a luxury that you most likely don’t need. Unless you want to record every moment of the day on your property, you can skip this feature, which can be expensive on wireless indoor surveillance cameras and uses a lot of Wi-Fi bandwidth and internet data.     Another feature you probably don't need is an extremely wide field of view, which can distort the image. A 130-degree field of view is usually sufficient.     Finally, modern Wi-Fi security IP cameras have a host of smart features to give you more detailed information about what’s going on in your home without you having to pull up the video feed. These software-based features tend to increase the price of the camera and aren't essential, although they're nice to have. They include features such as person detection, which allows the camera to alert you that a person is on your property, rather than just telling you motion was detected. The ability to set activity zones means the camera will only notify you about motion in a certain area of the image (ignoring, for example, a tree that frequently blows in the wind). Other nice-to-have smart features include the ability to work with smart home systems, such as Amazon’s Alexa Google’s Assistant and Apple’s HomeKit, and to integrate with smart door locks to allow for secure in-home deliveries.     What Are the Privacy Concerns of Home Security Cameras?     Cameras can record video all the time or when they detect motion, which means every time you or someone else walks into your garden or past your video doorbell. Before installing cameras in and around your home, make sure every member of your household knows they're there and is comfortable with them. Cameras can be hacked, with your footage monitored or even posted to the internet. However, the measures we discuss in How to Keep Your Security Cameras Safe will reduce this risk considerably.     We strongly recommend that you enable any built-in privacy features that the camera offers, and it can be perfect as baby monitor. For example, cameras can be turned off in the mobile app or geofencing technology can turn them off automatically when someone in your family with a smartphone is home.     What Are Some Uses of Home Security Cameras Besides Preventing Burglary?     Today’s home security cameras, including outdoor surveillance camera, are multifunctional and can be used for much more than just monitoring your property for intruders. Here are just a few other uses for home security cameras:     Baby Monitor: Set up an indoor camera in your baby’s room and view a live feed wherever you are, as long as you have an internet connection. You’ll need a camera capable of recording 24/7 and it will need to be plugged in, but as long as it has two-way audio and will send alerts on sound or motion it will work as a reliable monitor.     Pet Cam: Indoor, outdoor or other cameras can be used to keep an eye on your dogs, cats, chicken coop, or bunny hutch. Some cameras can specifically alert you to the noise of a dog barking so you can talk to your pet with a two-way talk feature.     Wildlife Cam: Place a battery-powered camera with night vision capabilities at the end of your garden and keep an eye on destructive deer or predatory raccoons, or enjoy the sights and sounds of nocturnal nature on your property.     Smart Home Trigger: If you have other smart home devices in your home, your camera, or action monitor, can be linked with them so they can respond automatically. For example, the motion sensor in an outdoor camera can turn smart lights inside if it detects motion in your driveway when you come home.     What Are Some Other Ways to Prevent Burglary?     One of the most effective ways to prevent burglary is to install a home security system with door and window sensors and a connection to a monitoring station, so the authorities can be notified even if you're not there. Less expensive ways to prevent burglary include installing basic physical security devices such as padlocks, door and window locks, grates, bars, and bolts on any accessible entries. “If you have a limited budget, focus on physical security devices, such as a security door brace that prevents a door from being kicked, says security consultant Frankel. Another option is to apply clear security film to windows to make them shatter-resistant.     Light is also a good deterrent. Outdoor lighting, motion-activated or programmed to come on at sunset and turn off at sunrise, can keep your home illuminated and make it harder for a thief to stay out of sight. Keeping your landscaping tidy and trimmed will help remove potential hiding spots.     Maintaining signs of occupancy even when you are gone can help deter potential thieves. Some ways to do this include using automated shades and programmed smart lighting to simulate someone being home, and making sure to cancel any newspaper or package deliveries when you're gone. A loud (although not necessarily large) dog is also a great deterrent.

Publish Date: 2021/09/05

Connect Your Car Lights To Your Trailer Lights The Easy Way

Description: Connect Your Car Lights To Your Trailer Lights The Easy Way     Trailer lighting has come a long way. Whether talking about exterior trailer lights, including markers and stop/tail/turn lamps, or interior trailer dome lights, you've made it clear to lighting suppliers you want longer lasting products for your truck fleets. Now you have them.     Last fall, Truck-Lite introduced for the reefer market two LED trailer dome lights whose diodes have a rated life of over 100,000 hr. The first product, the 80250C, is designed with the same dimensions as current fluorescent lamps, making it easy for retrofitting or use as a new product straight from the OE. The white LED uses multi-volt technology, Truck-Lite explains, rated to run between 10 and 30 volts.     LED technology, Truck-Lite points out, is an excellent fit for refrigerated trailers since LEDs work extremely well in cold temperatures. The manufacturer also states it has given the LED dome light a low profile design so drivers loading/unloading the trailer won't have a problem with insufficient overhead clearance.     The company says another advantage of the LED design is its “instant-on” technology. As soon as the operator turns the switch on, the LED is on and as bright as it will get, according to Truck-Lite, meaning the driver doesn't have to wait for the dome LED RV lights to warm up before unloading cargo.     The second product from Truck-Lite is the LED truck trailer light. It has all the benefits of the first dome lamp, but offers fleets flexibility in where they can mount it inside the trailer. The strip lamp has a low-profile design and comes in 2- and 4-ft. lengths that can be mounted in the upper corner at a 45-deg. angle or surface-mounted flat against the ceiling.     Truck-Lite says that with the introduction of the two new white LEDs it now has LED lamps available to cover any lighting application on a trailer a fleet could want. The company adds that the trend among fleets toward the use of more LEDs continues and most are spec'ing them in one position or another on their trucks.     For trailers that operate in non-refrigerated and other higher-temperature applications, Phillips Industries offers its fluorescent Permalite dome lamp. The manufacturer says that for safety, the light is designed to withstand higher temperatures than other similar units.     Late last summer the company launched another product called Permalogic, which is designed to control the trailer's dome light, such as LED marine lights. According to Phillips, fleets can save on energy and voltage by having these lamps switched off when the trailer is moving down the road. They can also prevent overheating of the lights and subsequent problems from that.     Since the dome lights run off the same blue wire as the ABS, Phillips reports that Permalogic can also avoid service problems in a panic situation by making sure there's enough power reserve to activate the ABS when needed. The controller unit in Permalogic shuts the lights off automatically if voltage gets too low, or at pre-determined elapsed time intervals, Phillips explains.     And as an added safety feature should a driver forget to turn the LED truck stop tail lights off after loading or unloading the trailer, Permalogic will turn them off for him/her the first time the driver steps on the truck brakes. Permalogic works with Permalite and competitive makes fluorescent and LED dome lights.     Phillips says its next step will be to develop a whole system — through the use of newer electronic technology in lighting products, including LED side marker clearance lights — capable of conserving the most power so fleets can run LED combination lights and other accessories longer without having to recharge the batteries.     Connect Your Car Lights, such as LED license plate lights, To Your Trailer Lights The Easy Way         When it comes to "electricity", many people are either scared silly of it, or run the other way rather than try to learn about it. Since it is a powerful force, it certainly is something to be respected. For us vehicle owners, perhaps we understand that our cars and trucks have a battery under the hood that needs occasional replacement, and light bulbs that may burn out after several years. Beyond that, many of us are ready to leave any electrical work to the "experts".     If you have recently purchased a trailer, "electricity" will eventually become a question you'll need to answer, as in, how do I connect my trailer's lights to my tow vehicle's lights? It may seem obvious that your trailer has tail, turn, and brake lights at the rear which need to operate in sync with your car's lights. That isn't going to happen by magic. We are here to share some wonderful news with you: for the vast majority of vehicles on the road, CARiD has made it quite easy to 'make the connection'. Follow along and discover how simple it is to connect these two systems together. We will be looking at specific components within our Trailer Hitch Wiring & Electrical Store.     The scope of this article will presume that your trailer has what the industry calls a "4-flat" wiring connector, which is the standard on many new trailers sold in the U.S. This article will explain the purchase of the correct harness for your vehicle, so that the two can be joined. The trailer plug should be a '3-male, 1-female', and the tow vehicle plug should be the opposite, or '3-female, 1-male'.     

Publish Date: 2021/09/05

Different kinds of industrial used belts

Description: Different kinds of industrial used belts     Conveyor Systems are mechanical devices or assemblies that transport material with minimal effort. While there are many different kinds of conveyor systems, they usually consist of a frame that supports either rollers, wheels, or a belt, upon which materials move from one place to another. They may be powered by a motor, by gravity, or manually. These material handling systems come in many different varieties to suit the different products or materials that need to be transported.     Conveyor Belt System Speed/Rated Speed     Belt conveyors are typically rated in terms of belt speed in ft/min. while powered roller conveyors described the linear velocity in similar units to a package, carton, etc. moving over the powered rollers. Rated speed applies to apron/slat conveyors and drag/chain/tow conveyors as well.     Belt Conveyors are material handling systems that use continuous belts to convey products or material. The belt is extended in an endless loop between two end-pulleys.  Usually, one or both ends have a roll underneath. The conveyor belting is supported by either a metal slider pan for light loads where no friction would be applied to the belt to cause drag or on rollers. Power is provided by motors that use either variable or constant speed reduction gears.     The belts themselves can be made from numerous materials, which should correspond to the conditions under which the belt will be operating. Common conveyor belting materials include rubber, plastic, leather, fabric, and metal. Transporting a heavier load means a thicker and stronger construction of conveyor belting material is required. Belt conveyors are typically powered and can be operated at various speeds depending on the throughput required. The conveyors can be operated horizontally or can be inclined as well. Belt conveyors can be troughed for bulk or large materials.     A rubber v-belt is a flexible machine element used to transmit power between a set of grooved pulleys or sheaves. They are characterized as belts having a trapezium cross-section. V-belts are the most widely used belt drives since their geometry causes them to wedge tightly into the groove as the tension is increased. As the belt wedges into the groove, friction between the surface of the belt is increased, allowing high torques to be transmitted. The increased friction minimizes the loss of power through slippage.     Before going deeper into v-belts, it is important to know an overview of belt drives. Belt drives are machine elements that are used to transmit power between two or more rotating shafts, usually with parallel axes of rotation. The belts are looped over pulleys attached to the driver and follower shafts. These pulleys are placed at a certain distance to create an initial tension on the belt. When in operation, the friction causes the belt to grip onto the pulley. The rotation of the driver pulley increases the tension on one side of the belt creating a tight side. This tight side applies a tangential force to the follower pulley. Torque is then applied to the driven shaft. Opposite the tight side is the slack side where the belt experiences less tension.     There are many types of belt drives used today., such as agricultural harvester V belts, The earliest type of belt drive uses a flat belt made from leather or fabric. Flat belts operate satisfactorily in low-power applications such as farm equipment, mining, and logging. At higher loads and speeds, they tend to slip on the surface of the pulleys and climb out of the pulley. Another early type of belt drive is a rope drive made from cotton or hemp. Rope drives are used on two pulleys with a V-shaped groove. This solved the problem of climbing out of the pulley enabling belt drives to be used over large distances. Later, this was developed into round beltswhich are made from elastomeric materials such as rubber, nylon, or urethane. The development of these elastomeric materials also brought the progress of belt drive technology. Belts such as v-belts, ribbed belts, multi-groove belts, and timing beltswere made to solve the problems of previous belt drives.     An entire v-belt can be regarded as a composite material composed of different types of rubber and reinforcements. In its usual application, a v-belt is subjected to combined tensile and compressive stresses. The top side of a v-belt is subjected to a tensile force directed longitudinally, while the bottom side is compressed due to the compression against the grooves and bending as a belt segment passes the pulley. Moreover, a different type of material is also needed at the surface of the belt. Ideal material for the surface must have a high coefficient of friction and increased wear resistance.     Understanding All the Automotive Belts in Your Car     Your car’s engine has a number of mechanical parts attached to it that perform essential functions like delivering power (the alternator), cooling your engine (the water pump), helping you to drive more easily (the power steering pump) and keeping you comfortable (the air conditioner compressor). Without a drive belt, none of these parts would work.     The purpose of drive belts is to deliver power between different engine components. They work by means of friction between the belt and pulley, which is why loose belts can cause various components to work poorly, or not at all.     That’s a very basic overview of car belts, and by no means all-inclusive. Let’s talk in a bit more detail about different types of belts and how they work in your car.     Some vehicles have multiple belts, called v-belts, including motorcycle belts, that come off the crankshaft of the engine to drive the alternator, the air conditioning compressor, the power steering pump and the water pump. In older vehicles, v-belts were the standard.     Timing belts     The timing belt is also sometimes called a camshaft drive belt or a Gilmer belt. It is a notched belt, made of rubber, that enables the crankshaft to turn the camshaft, and opens and closes the engine valves synchronously with the pistons. In late model vehicles, the timing belt has essentially replaced the metal timing chain.     The advantage of the timing belt over the timing chain is that if the timing belt fails, there is less potential for damage to valves and pistons.     Symptoms, causes, and effects of failed or failing drive belts     V-belts: If a v-belt is failing, it will squeak, and accessories may not work properly. If it fails, the accessories that it powers will stop working. Causes can include ordinary wear or fluid contamination. Belts are also widely used in other electronics, like lawn mower belts.     Serpentine belts: If a serpentine belt is failing, accessories may not work properly, car may be hard to start or not start at all, and the belt may emit a squeaking, screeching or chirping sound. Causes can include cracking, wear or stripping, fluid contamination and poor belt tension.     Timing belts: If a timing belt is failing, your car may idle rough, or you may hear a slapping sound from the motor compartment. If it fails, your car will not work at all. There is also a possibility of serious damage to the valves and pistons. Causes can include wear, slipping or fluid contamination.

Publish Date: 2021/09/05

How prefab houses work?

Description: How prefab houses work?     With historic wildfires sweeping the West Coast and burning over 3.2 million acres in California alone, it is clear in 2020 that the climate change emergency is upon us. Dvele Cofounder and CEO Kurt Goodjohn's purpose is to create a new generation of ultra-energy-efficient, self-powered prefabricated homes that will inspire society’s transition to a clean energy future. The company not only manufactures the prefab container houses, but also has designed technology to ensure that the homes can be reproduced consistently and affordably at scale.      All Dvele prefab homes are completely self-powered by solar energy, thus addressing climate change and eliminating dependency on the power grid. The homes utilize advanced materials and assembly techniques in order to ensure that they require 84% less energy per square foot than a traditionally-built home. With such efficiency, Dvele homes are capable of utilizing the solar array and battery backup system to make them fully grid-independent and insulated from the inconveniences and safety risks associated with long-term power outages, not to mention significant financial savings.     “We've redesigned the home from the ground up,” says Goodjohn. “Our approach not only results in ultra-efficient living environments that can generate more energy than it takes to operate, but also ensures the safety, health and wellness of occupants.”     Kurt Goodjohn and his brother Kris Goodjohn stumbled into the construction industry, starting off building luxury homes using traditional, stick-built construction. Quickly, they realized how outdated, inefficient, and uninspiring these methods were. They had seen prefab construction projects on a trip to Europe and wondered why the homes weren’t more popular in North America. So over beers one night, they decided to found a company in the prefab industry.     Now, Kurt Goodjohn feels he has tapped into his life purpose. “I have always been a strong advocate for the notion that everyone should leave the world better off than they found it,” he says. “At Dvele, we are accomplishing this by disrupting an age-old industry and bringing it into the modern age. Our company contributes to minimizing the overall environmental impact of homes and enhances the way they function to benefit the health and wellness of occupants.”     As a result, Goodjohn never feels that he really is “working” because he is pursuing something truly important. “There’s absolutely nothing my brother and I would rather be doing than building this company. We passionately believe that what we are doing will have a positive impact on the world and we have an unwavering determination to lead the change necessary in the new home space,” he says.     In the beginning, the greatest challenge the Goodjohns faced was getting other people to believe in the value of what they were doing with Dvele. However, they remained determined. “Trust your gut,” Kurt Goodjohn advises other aspiring entrepreneurs and changemakers. “When you're young, you really don't have a lot of experience, you don't know what will work or what will fail. So, it's actually the best time to just do what you think is right and learn as you go. My brother and I wouldn't be doing what we are doing today had we listened to all of the naysayers who told us it could never be done.”     Prefab house construction     Prefab houses are constructed from the inside out. They are manufactured in the following order in a couple of days or less, with inspections following each step (the process can take longer if the buyer has customized the home):     The floors are assembled first. There is usually a wood frame under the floor for attachment of wall panels.     Wall panels are attached next with bolts and nails. Panels are insulated and windows cut out before the panels are attached.     Once the house structure is in place, the plumbing, electrical wiring and drywall (including the ceiling) are installed.     The roof, typically constructed in another part of the factory, is set on top of the walls. In some prefabs, workers attach the roof on-site after the rest of the house is constructed.     Exterior and interior finishes are added, including siding, cabinets, vanities and backsplashes. The walls are also painted.     Once the housing units are constructed, they need to get to the owner's land. The transportation of the modules is limited by roadways, overhangs and power lines. The builders have to scout out all these factors before delivery, but in general each unit must be less than 16 feet wide, 60 feet long and 11 feet high. Because travel can be unpredictable, buyers are usually on site with independent contractors to inspect the units for scrapes and cracks.     The house has to have someplace to sit, so a foundation is required. Before the home arrives, homeowners must have the land excavated and have a foundation in place. The foundation can be poured concrete, concrete blocks, basements or crawl spaces.     The house arrives and is placed by crane on the foundation. Workers use heavy-duty cables to move the units, which come together at points called marriage walls. The marriage walls tie the house together and ensure that it is level and properly bolted together. At this point, the roof is placed if it was not factory-installed. A hinged roof, also made in the factory, is unfolded onto the house. The entire delivery and placement of the house can usually be completed in about a day. After that, decks, staircases and extras can be installed.     Variables such as customization, financing and factory schedules can contribute to the process, but from choosing the house to completion, most manufacturers give a timeframe of a few months.      Modern prefab houses     Although the concept of modern prefab design has been around since the 60s, the architectural movement didn't take off until early 2000. As technological advances like SIP panels (structural insulating that is precut and can be locked together) were made and interest in residential architectural design blossomed, architects turned their attention to prefab houses. The goal was to create a home that could be transported to a building site, be easily erected and look like modern architecture -- all within a reasonable budget.     To further stoke the flames of interest, Dwell magazine held a modern prefab invitational in 2003 to create an economical flat pack container house that could be mass-produced. Allison Arieff, the former editor of Dwell, had written the 2002 book Prefab, which profiled modern prefab prototypes. Nathan Wieler and Ingrid Tung contacted Arieff with the hopes of obtaining more information about how to build a modern prefab home. Instead, Arieff asked the couple if they'd be interested in using their land in Pittsboro, N.C., as the site for a design competition. With an initial construction budget of $200,000, the couple agreed and soon was helping the magazine create the criteria for the home and judging designs .     The Dwell invitational created an opportunity to take the modern prefab concept and make it a reality, with the goal of introducing mass-produced prefab homes with architectural modern flair to the market. However, challenges remained. The architectural firm Resolution: 4 Architecture delivered the design, but the project went $50,000 over budget, resulting in the reduction of the homes footprint in order to stay within budget .     The cost of a modern prefab home remains the chief complaint today, with the average modern prefab home running about $175 to $250 per square foot . In fact, Dwell magazine is now offering modern prefab homes through their company Empyrean. Proponents of the movement point out that although many of the products available cost as much as, if not more than, stick-built homes, homeowners can save money in design and construction costs. Many architect-designed homes exceed $300 per square foot, not including design fees . After all, you're not paying for one-of-a-kind architecture. The architect is reselling the design, and even if modifications are needed, those costs are usually small.     When it comes to mass-producing affordable modern prefab homes, Rocio Romero is one of the most recognized architects. Romero's company, located in Perryville, Mo., creates flat-packed cubelike houses with sleek, modern exteriors. House kits range from $23,650 to $45,255 . Finishes and amenities also impact the price. Romero uses a series of interlocking panels for ease of building construction. The company also sends a videotape along with instructions for the general contractor or the handy homeowner who goes it alone.     While some prefabs qualify as "traditional homes" to mortgage companies because they use some of the methods of stick-built homes, others do not. But many new modern prefabs are being introduced to home-builders, with shipping container room included. The Swedish company, IKEA, introduced its modern prefab home, the BoKlok, to the European market. In 2006, the Walker Art Museum presented an exhibit around modern prefab, "Some Assembly Required: Contemporary Prefabricated Houses." And as the market demands more environment- and wallet-friendly housing choices, the modern prefab market should continue to grow in the scope of its offerings.

Publish Date: 2021/09/05

4 Amazing Health Benefits of Sunflower Seeds

Description: 4 Amazing Health Benefits of Sunflower Seeds     Sunflower seeds may conjure up memories of baseball games growing up, but they are actually a much more wholesome food than the hot dogs and other foods that may also remind you of ballpark fare. Adding sunflower seeds to your diet could do wonders for your skin, heart, immunity and overall health. Read below to find out four good reasons to start adding them to your favorite snacks for a serious health boost.     Sunflower Seeds Nutrition     The following nutritional information is for a one-ounce serving of dry roasted sunflower seeds, without salt:     Calories: 165     Total Fat: 14 grams     Saturated Fat: 1.5 grams     Monounsaturated Fat: 3 grams     Polyunsaturated Fat: 9 grams     Cholesterol: 0 milligrams     Sodium: 1 milligram     Carbs: 7 grams     Fiber: 3 grams     Sugars: 0 grams     Protein: 5.5 grams     Vitamin A: 2.5 IU (0% Daily Value)     Vitamin C: 0.5 mg (4% DV)     Calcium: 20 milligrams (2% DV)     Iron: 1 milligram (6% DV)     While sunflower seeds are pretty high in fat for a one-ounce serving, they are made of mostly mono- and polyunsaturated fats, which are a great anti-inflammatory and heart-healthy source of fats our bodies need. Additionally, they are a good source of fiber and protein, adding a nice nutrition boost to your favorite granola bars, salads and other recipes.     Sunflower seeds are also almost negligent in sodium on their own, but many packaged sunflower seed products are loaded with salt—one popular brand packs 79% of your daily sodium limit per serving! It's important to be mindful of the nutrition label whenever you're stocking up on sunflower seeds to use for snacking or in a recipe.     Sunflower Seeds Boast Anti-Inflammatory Benefits     You don't just have to eat the trendy seeds—like chia and hemp—to reap the anti-inflammatory benefits they have to offer. A study out of Columbia University found consuming sunflower and other seeds, like roasted shine skin pumpkin seeds, five or more times per week to be associated with lower levels of inflammation—which the authors of the study may be why consumption of them is also related to a reduced risk for several chronic diseases.     Sunflower Seeds Boost Your Heart Health     Unlike saturated fat, moderate unsaturated fat consumption has actually shown to improve one's heart health. A study out of Harvard University found increased seed consumption—sunflower seeds included—to be associated with a lower risk for cardiovascular disease, as well as CVD risk factors, such as high cholesterol and blood pressure. Making the effort to consume more heart-healthy fats, like the mono- and polyunsaturated fats found in sunflower seeds and sunflower seed kernels, can make a huge impact on your heart health (learn more about the best and worst foods to eat for heart health).     Sunflower Seeds Help to Prevent and Fight Sickness     Sunflower seeds are a good or excellent source of nearly a dozen essential vitamins and minerals, two of them being zinc and selenium. Zinc is an integral part of the immune system, as it helps both to develop and maintain proper function of immune cells. Additionally, zinc functions as an antioxidant to fight off free radicals.     Selenium also plays a role in fighting inflammation and infection, along with boosting immunity, to ensure our bodies are producing a proper response to any intruders in the body. This mineral is an important part of achieving mental health and preventing neurodegenerative disorders (like Alzheimer's) as well.     Sunflower Seeds Are a Great Food for Expecting Mothers     Whether you're hoping to have a baby, are pregnant or are just trying to follow a well-balanced diet, sunflower seeds have a lot to offer. These seeds are a good source of zinc and folate, while being an excellent source of vitamin E. Vitamin E is essential for prenatal health, as it helps the fetus develop and use red blood cells and muscles. Folate supports the placenta and helps prevent spina bifida, while zinc helps produce insulin and enzymes.     Vitamin E is also a key nutrient for achieving that  pregnancy glow. , which is abundant in walnuts. You've likely purchased a skincare product that touts having vitamin E in it, as it fights against UV damage and nourishes your largest organ. Sunflower seeds pack more than one-third of your daily needs.     Shine skin pumpkin seeds may be tiny, but they are densely packed with useful nutrients and nutraceuticals such as amino acids, phytosterols, unsaturated fatty acids, phenolic compounds, tocopherols, cucurbitacins and valuable minerals. All these bioactive compounds are important to a healthy life and well-being. The purpose of this review is to merge the evidence-based information on the potential use pumpkin seeds as a functional food ingredient and associated biological mechanisms, collected from electronic databases (ScienceDirect, ResearchGate, PubMed, Scopus and Google Scholar) up to January 2020. Bioactive compounds in pumpkin seeds exhibit promising activities such as anthelmintic, antidiabetic, antidepressant, antioxidant, antitumor and cytoprotective. Furthermore, these bioactives carry potential in ameliorating microbiological infections, hepatic and prostate disorders. As evidenced from literature, pumpkin seeds, like roasted almond kernel, show potential to be used as both a traditional and functional food ingredient provided further animal and clinical investigations are carried out to establish the respective molecular mechanisms and safety profile.

Publish Date: 2021/09/05

What is an efficient carburetor design and other machinery parts

Description: What is an efficient carburetor design and other machinery parts     A carburetor is a mechanical device that mixes a certain percentage of gasoline with air under the action of a vacuum generated by engine operation. As a precise mechanical device, the carburetor uses the kinetic energy of the inhaled air flow to atomize the gasoline. Its important role for the engine can be called the heart of the engine. Its complete device should include starting device, idling device, medium load device, full load device, acceleration device. The carburetor will automatically proportion the corresponding concentration and output the corresponding amount of mixture according to the different working conditions of the engine. In order to make the mixture more uniform, the carburetor also has the effect of atomizing the fuel for the normal operation of the machine.     The clutch assembly is located in the flywheel housing between the engine and the gearbox. The clutch assembly is fixed on the rear plane of the flywheel with screws. The output shaft of the clutch is the input shaft of the gearbox. When the car is running, the driver can step on or release the clutch pedal as needed to temporarily separate and gradually engage the engine and the gearbox, so as to cut off or transmit the power input from the engine to the transmission. Clutch is a common component in mechanical transmission, which can separate or engage the transmission system at any time. Its basic requirements are: smooth joining, rapid and thorough separation; convenient adjustment and repair; small outline size; small quality; good wear resistance and sufficient heat dissipation capacity; convenient operation and labor saving. Commonly used are divided into jaw type and there are two types of friction.     Caliper disc brake is a type of disc brake. Its rotating element is a metal disc that works on the end face, called a brake disc. The fixed element is a brake block composed of a friction block with a small working area and its metal back plate. There are 2 to 4 in each brake. These brake blocks and their actuating devices are installed on both sides of the brake disc. In the clamp-shaped bracket, it is collectively called a brake caliper. The brake disc and the brake caliper together constitute a caliper disc brake.     Muffler means that for airflow pipes that have noise transmission at the same time, you can use pipes and elbows with sound-absorbing linings, or use noise-reducing devices such as pipes with sudden changes in cross-sectional area and other discontinuous acoustic impedance to attenuate or reduce the noise in the pipe. Reflect back. The former is called a resistive muffler, and the latter is called a resistive muffler. There are also impedance composite mufflers.     Starter and igniter coil are the lighting devices of fluorescent lamps. It is composed of a neon bulb and a small capacitor equipped with a fixed static contact piece and a moving contact piece made of a hot bimetallic piece. Connected to the starting circuit of the fluorescent lamp. A device installed in the gas discharge light source circuit to start and ignite the discharge lamp, also known as a trigger.     Durability is very important for current diesel engines. Diesel engine parts manufacturers are trying to make the engines live as long as possible before overhaul. The time to overhaul for an engine is usually dictated by high oil consumption or blowby. Therefore, it is necessary to understand how wear affects the cylinder kit dynamics, oil consumption, and blowby in an engine. This paper explores the effect of power cylinder component (rings and cylinder bore) wear by using a cylinder kit dynamics model. The model predicts how wear will affect ring motion, inter-ring gas pressure, blowby, etc. The parameters studied were: liner wear, ring face wear, and ring side wear. Two different engines were modeled. The characteristics of these two engines are very different. As a result, the effects of wear are different and the corresponding durability will be different. This illustrates the need to model each individual type of engine separately. The modeling shows that top ring face wear is very significant for maintaining good oil and blowby control. Liner wear is important, but does not have as large an effect as ring wear. The effects of side wear are significant for these two cases.     The design of an engine carburetor is traditionally based on a mechanical device that uses a shutter to control the amount of fuel intake. The fuel is mixed with air to form fuel mixture that is burnt in engine cylinders. This approach has several inherent issues. First, the shutter opening is controlled by creating a vacuum that results in required amount of fuel injected into carburetor chamber. As the speed of a vehicle increases by pressing accelerator, more fuel is required in the carburetor chamber. The rate of increase in fuel cannot be accurately calculated by a mechanical device. Second, the amount of air intake results in an imbalance in fuel mixture ratio. Third, the carburetor's efficiency degrades with age, resulting poor fuel efficiency. This paper proposes EFI for small vehicles. A test case was developed for a two-wheel motor-bike by using an ARDUINO board. The proposed solution was implemented in the engine of motor-bike with minor changes in the carburetor. The cost was quite comparable with mechanical carburetor, and the results were quite promising.

Publish Date: 2021/09/05

Understanding Auto Parts

Description: Understanding Auto Parts     The basic idea of a car is pretty simple — turn wheels to pull you down the road. But, as illustrated by the hundreds of individual auto parts for sale at your local Pep Boys, AutoZone or Napa Auto Parts, it actually takes a lot of machinery to make cars work.     If you're trying to figure out what all the parts in your car do, HowStuffWorks AutoStuff is the place for you. Here's a collection of our key car part articles.     Engine System     How Car Engines Work     It's the reason you can put the pedal to the metal and go from zero to 60 in about 8 seconds. The car engine is a piece of engineering genius and one of the most amazing machines we use on a daily basis. Learn how the four-stroke internal combustion engine works.     How Diesel Engines Work     Ever wonder what the difference is between a gasoline engine and a diesel engine? Diesels are more efficient and cheaper to run than gasoline engines. Instead of using carburetion or port fuel injection, diesel engines use direct fuel injection. Find out what else makes diesel engines different! A turbocharger is actually an air compressor that compresses air to increase the air intake with turbocharger assy. It uses the inertial impulse of the exhaust gas from the engine to push the turbine inside the turbine chamber     How Hemi Engines Work     The HEMI engine has an awesome design and great performance, and it's pretty unique in operation. With the revitalization of the HEMI in the 2003 Dodge trucks, industry and consumer attention is once again on this interesting configuration. Check out how the HEMI works and see what makes it different from the typical engine design.     How Rotary Engine blocks Work     A rotary engine is an internal combustion engine, but it's not like the one in most cars. Also called a Wankel engine, this type of engine performs intake, compression, combustion and exhaust in a different part of the housing. Learn about the unique rotary setup and how it compares performance-wise to a piston engine.     How Radial Engines Work     Radial engines reached their zenith during WWII. But today they are not that common. One place where you can still see the radial engine's influence is in the two-cylinder engine of a Harley-Davidson motorcycle. This remarkable engine can be thought of, in a way, as two pistons from a radial engine. Find out about radial engines.   How Quasiturbine Engines Work     The quasiturbine engine takes the Wankel concept and improves on it: Instead of three combustion chambers, it has four, and the setup of a quasiturbine allows for continual combustion. That means greater efficiency than any other engine in its class. Learn about the quasiturbine and why it might be the most promising internal combustion engine yet.     The automobile transmission system is composed of a series of crankshaft, flywheel, clutch, transmission, drive shaft, drive axle, etc. with elasticity and rotational inertia. The power is outputted by the engine and transmitted to the drive wheels through the clutch, transmission after the torque increase and change, drive shaft, main reducer, differential and half shaft.     How Camshafts Work     The camshaft has a huge effect on engine performance. It helps let the air/fuel mixture into the engine and get the exhaust out. Learn all about the camshaft and how a new one can radically change an engine's behavior.     How Superchargers Work     Overhal gaskets are parts used for sealing in automobiles, mainly made of elastomers     Since the invention of the internal combustion engine, automotive engineers, speed junkies and race car designers have been searching for ways to boost its power. One way is by installing a supercharger, which forces more air into the combustion chamber. Learn how superchargers can make an engine more efficient.     How Turbochargers Work     When people talk about race cars, or high-performance sports cars, the topic of turbochargers almost always comes up. Turbochargers use some very cool technology to make an engine more powerful, but the concept is really quite simple. Find out how turbos increase the speed. The engine repair kit is very necessary.     How Fuel Injection Systems Work     The last carburetor-equipped car came off the assembly line in 1990. Since then, fuel injectors have been the primary means of getting gasoline into the engine cylinder so it can combust and you can drive. Find out how fuel-injection systems work.     Power Train     How Manual Transmissions Work     The cylinder head is mounted on top of the cylinder block, sealing the cylinder from above and forming the combustion chamber. It is often in contact with high temperature and high pressure gas, so bear a large thermal and mechanical load.     If you drive a stick-shift car, then you may have a few questions floating around in your head. Have you ever wondered, What would happen if I were to accidentally shift into reverse while I am speeding down the freeway? Would the entire transmission explode? Find out all about manual transmissions.     How Automatic Transmissions Work     Automatic transmissions take the work out of shifting. A truly amazing mechanical system, the automatic transmission in a car accomplishes everything a manual transmission does, but it does it with one set of gears. Learn how the whole setup works.     How Clutches Work     You probably know that any car with a manual transmission has a clutch -- it connects and disconnects the engine and transmission. But did you know that automatics have clutches, too? Learn how the clutch in your car works, and find out about some interesting and perhaps surprising places where clutches can be found.     How CVTs Work     In a regular transmission, the gears are literal gears -- interlocking, toothed wheels. Continuously variable transmissions, on the other hand, don't have interlocking gears. The most common type operates on a pulley system. Learn all about the smooth-operating, ultra-efficient CVT.     How Differentials Work     Without a differential, the driven wheels (front wheels on a front-wheel drive car or rear wheels on a rear-wheel drive car) would have to be locked together, forced to spin at the same speed. Find out how this essential component allows the wheels to rotate at different speeds.     Braking System (including braking pads and braking shoe)     In the cylinder block of the car engine, there are several waterways for cooling water circulation, and placed in the front of the car radiator (commonly known as the water tank) through the water pipe connected to form a large water circulation system, the upper outlet of the engine, equipped with a water pump, driven by the fan belt, the engine block waterway hot water pump out, the cold water pumped into.     A car’s brakes are probably the most critical system on the vehicle -- if they go out, you have a major problem. Thanks to leverage, hydraulics and friction, braking systems provide incredible stopping power. Find out what happens after you push the brake pedal.     How Disc Brakes Work     Disc brakes are the most common brakes found on a car's front wheels, and they're often on all four. This is the part of the brake system that does the actual work of stopping the car. Find out all about disc brakes -- even when to replace the pads.   How Anti-lock Brakes Work     Stopping a car in a hurry on a slippery road can be challenging at best and at worst, very, very scary. Anti-lock braking systems (ABS) help alleviate the danger. Learn how anti-lock brakes prevent skidding, check out what that sputtering is and find out how effective they really are.     How Power Brakes Work     Power brakes are fairly ingenious machines -- they let you stop a car with a simple twitch of your foot. The concept at the heart of the power braking system is force multiplication -- a whole lot of force multiplication. Get inside the black cannister that provides the power.     How Master Cylinders and Combination Valves Work     We all know that pushing down on the brake pedal slows a car to a stop. We depend on that every day when we drive. But how does this happen? The master cylinder provides the pressure that engages your car brakes. Learn how the master cylinder works with the combination valve to make sure you can brake safely.     Steering, Suspension and Tires     How Steering Works     When it comes to crucial automotive systems, steering is right up there with the engine and the brakes. Power steering systems make the job a whole lot easier, and the internal workings are pretty cool. What happens when you turn your car is not as simple as you might think. Find out all about car steering systems.     How Car Suspensions Work     All of the power generated by a car engine is useless if the driver can't control the car. The job of a car suspension is enormous: maximize the friction between the tires and the road surface, provide steering stability and ensure the comfort of the passengers. Learn how car suspensions work and where the design is headed in the future.     How Tires Work     In the market for new set of tires? All of the different tire specifications and confusing jargon the tire sales clerks or "experts" are shouting at you making your head feel like a tire spinning out of control? Find out all about car tires, including what those sidewall symbols mean!     How Self-inflating Tires Work     Self-inflating tires perform two crucial functions: They automatically maintain ideal tire pressure for safety and performance in standard conditions, and they allow the driver to alter psi on the fly to adjust to changing terrain. Learn how self-inflating systems like the Hummer's CTIS work.     How Sequential Gearboxes Work     Combine the ease of an automatic with the driver control of a manual, and what you've got is a sequential manual transmission. Instead of having to navigate an H pattern, a simple forward push advances the gear. It's the transmission used by race cars and an increasing number of high-performance street cars. Learn all about the sequential gearbox.   How Torque Converters Work     Cars with an automatic transmission have no clutch that disconnects the transmission from the engine. Instead, they use an amazing device called a torque converter. Find out all about the torque converter.     Electrical System     How Wires, Fuses and Connectors Work     Wires, fuses and connectors - they may sound like the most mundane parts on your car, but they are essential. Yeah, they help keep the tunes going for a long ride, and they make reading that map at night a lot easier. But, they're also necessary for things like the cooling fan in the engine and your anti-lock brakes. Learn why wires, fuses and connectors are so important!     How Ignition Systems Work     A car's ignition system is the key component that helps the engine produce maximum power and minimum pollution. Find out how much is riding on a well-timed spark.     How Car Computers Work     Cars seem to get more complicated with each passing year. Today's cars might have as many as 50 microprocessors on them. Essentially, you're driving around in a giant computer. Learn all about the various computer systems that control your car.     How Windshield Wipers Work     Without windshield wipers, a rain storm would make cars pretty much useless. What began as a hand-cranked system is now automatic, and only getting more so: There are now some windshield wipers that can actually sense rain. Learn the mechanics behind this essential automotive tool.     Exhaust System     How Catalytic Converters Work     A catalytic converter is one of the most important parts of a car's emissions control system. It treats the exhaust before it leaves the car and removes a lot of the pollution. Learn how catalytic converters reduce pollutants and help you pass the emissions test.     How Mufflers Work     Every car out there has a muffler -- it performs the crucial job of turning thousands of explosions per minute into a quiet purr. Mufflers use some pretty neat technology to dim the roar of an engine. Learn about the principles that make it work.     Other Car Parts     How Odometers Work     Mechanical odometers have been counting the miles for centuries. Although they are a dying breed, they are incredibly cool inside. Learn how this simple device tracks distance and find out about digital odometers.     How Cooling Systems Work     A car engine produces so much heat that there is an entire system in your car designed to cool the engine down to its ideal temperature. In fact, the cooling system on a car driving down the freeway dissipates enough heat to heat two average-sized houses! Learn all about fluid-based cooling systems.

Publish Date: 2021/09/05

Understanding Compressors

Description: Understanding Compressors     Compressors are mechanical devices used to increase pressure in a variety of compressible fluids, or gases, the most common of these being air. Compressors are used throughout industry to provide shop or instrument air; to power air tools, paint sprayers, and abrasive blast equipment; to phase shift refrigerants for air conditioning and refrigeration; to propel gas through pipelines; etc. As with pumps, compressors are divided into centrifugal (or dynamic or kinetic) and positive-displacement types; but where pumps are predominately represented by centrifugal varieties, compressors are more often of the positive- displacement type. They can range in size from the fits-in-a-glovebox unit that inflates tires to the giant reciprocating or turbocompressor machines found in pipeline service. Positive-displacement compressors can be further broken out into reciprocating types, where the piston style predominates, and rotary types such as the helical screw and rotary vane.     In this guide, we will use both of the terms compressors and air compressors to refer mainly to air compressors, and in a few specialized cases will speak to more specific gases for which compressors are used.     Types of Air Compressor     Compressors may be characterized in several different ways, but are commonly divided into types based on the functional method used to generate the compressed air or gas. In the sections below, we outline and present the common compressor types. The types covered include:     Piston     Diaphragm     Helical Screw     Sliding vane     Scroll     Rotary Lobe     Centrifugal     Axial   Due to the nature of the compressor designs, a market also exists for the rebuilding of air compressors, and reconditioned air compressors may be available as an option over a newly purchased compressor, including special process gas compressors.     Piston Compressors     Piston compressors, or reciprocating compressors, rely on the reciprocating action of one or more pistons to compress gas within a cylinder (or cylinders) and discharge it through valving into high pressure receiving tanks. In many instances, the tank and compressor are mounted in a common frame or skid as a so-called packaged unit. While the major application of piston compressors is providing compressed air as an energy source, piston compressors are also used by pipeline operators for natural gas transmission. Piston compressors are generally selected on the pressure required (psi) and the flow rate (scfm). A typical plant-air system provides compressed air in the 90-110 psi range, with volumes anywhere from 30 to 2500 cfm; these ranges are generally attainable through commercial, off-the-shelf units. Plant-air systems can be sized around a single unit or can be based on multiple smaller units which are spaced throughout the plant.     To achieve higher air pressures than can be provided by a single stage compressor, two-stage units are available. Compressed air entering the second stage normally passes through an intercooler beforehand to eliminate some of the heat generated during the first-stage cycle.     Speaking of heat, many piston compressors are designed to operate within a duty cycle, rather than continuously. Such cycles allow heat generated during the operation to dissipate, in many instances, through air-cooled fins.     Piston compressors are available as both oil-lubricated and oil-free designs. For some applications which require oil-free air of the highest quality, other designs are better suited.     Diaphragm Compressors     A somewhat specialized reciprocating design, the diaphragm compressor uses a motor-mounted concentric that oscillates a flexible disc which alternately expands and contracts the volume of the compression chamber. Much like a diaphragm pump, the drive is sealed from the process fluid by the flexible disc, and thus there is no possibility of lubricant coming into contact with any gas. Diaphragm air compressors with spare parts are relatively low capacity machines that have applications where very clean air is required, as in many laboratory and medical settings.     Helical Screw Compressors     Helical-screw compressors are rotary compressor machines known for their capacity to operate on 100% duty cycle, making them good choices for trailerable applications such as construction or road building. Using geared, meshing male and female rotors, these units pull gas in at the drive end, compress it as the rotors form a cell and the gas travels their length axially, and discharge the compressed gas through a discharge port on the non-drive end of the compressor casing. The rotary screw compressor action makes it quieter than a reciprocating compressor owing to reduced vibration. Another advantage of the screw compressor over piston types is the discharge air is free of pulsations. These units can be oil- or water- lubricated, or they can be designed to make oil-free air. These designs can meet the demands of critical oil-free service.     Sliding Vane Compressors     A sliding-vane compressor relies on a series of vanes, mounted in a rotor, which sweep along the inside wall of an eccentric cavity. The vanes, as they rotate from the suction side to the discharge side of the eccentric cavity, reduce the volume of space they are sweeping past, compressing the gas trapped within the space. The vanes glide along on an oil film which forms on the wall of the eccentric cavity, providing a seal. Sliding-vane compressors cannot be made to provide oil-free air, but they are capable of providing compressed air that is free of pulsations. They are also forgiving of contaminants in their environments owing to the use of bushings rather than bearings and their relatively slow-speed operation compared to screw compressors. They are relatively quiet, reliable, and capable of operating at 100% duty cycles. Some sources claim that rotary vane compressors have been largely overtaken by screw compressors in air-compressor applications. They are used in many non-air applications in the oil and gas and other process industries.     Scroll Compressors     Scroll air compressors use stationary and orbiting spirals which decrease the volume of space between them as the orbiting spirals trace the path of the fixed spirals. Intake of gas occurs at the outer edge of the scrolls and discharge of the compressed gas takes place near the center. Because the scrolls do not contact, no lubricating oil is needed, making the compressor intrinsically oil-free. However, because no oil is used in removing the heat of compression as it is with other designs, capacities for scroll compressors are somewhat limited. They are often used in low-end air compressors and home air-conditioning compressors.     Rotary Lobe Compressors     Rotary-lobe compressors are high-volume, low-pressure devices more appropriately classified as blowers. To learn more about blowers, download the free Thomas Blowers Buying Guide.     Centrifugal Compressors     Centrifugal compressors rely on high-speed pump-like impellers to impart velocity to gases to produce an increase in pressure. They are seen mainly in high-volume applications such as commercial refrigeration units in the 100+ hp ranges and in large processing plants where they can get as large as 20,000 hp and deliver volumes in the 200,000 cfm range. Almost identical in construction to centrifugal pumps, centrifugal compressors increase the velocity of gas by throwing it outward by the action of a spinning impeller. The gas expands in a casing volute, where its velocity slows and its pressure rises.     Centrifugal compressors have lower compression ratios than displacement compressors, but they handle vast volumes of gas. Many centrifugal compressors use multiple stages to improve the compression ratio. In these multi-stage compressors, the gas usually passes through intercoolers between stages.     Axial Compressors     The axial Low-Pressure Water Lubricating Oil-free Compressor achieves the highest volumes of delivered air, ranging from 8000 to 13 million cfm in industrial machines. Jet engines use compressors of this kind to produce volumes over an even wider range. To a greater extent than centrifugal compressors, axial compressors tend toward multi-stage designs, owing to their relatively low compression ratios. As with centrifugal units, axial compressors increase pressure by first increasing the velocity of the gas. Axial compressors then slow the gas down by passing it through curved, fixed blades, which increases its pressure.     Power and Fuel Options     Air compressors may be powered electrically, with common options being 12 volt DC air compressors or 24 volt DC air compressors. Compressors are also available that operate from standard AC voltage levels such as 120V, 220V, or 440V.     Alternative fuel options include air compressors that operate from an engine that is driven off of a combustible fuel source such as gasoline or diesel fuel. Generally, electrically-powered compressors are desirable in cases where it is important to eliminate exhaust fumes or to provide for operation in settings where the use or presence of combustible fuels is not desired. Noise considerations also play a role in the choice of fuel option, as electrically driven air compressors typical exhibit lower acoustical noise levels over their engine-driven counterparts.     Additionally, some air compressors may be powered hydraulically, which also avoids the use of combustible fuel sources and the resulting exhaust gas issues.      Compressor Machine Selection in an Industrial Setting     In selecting air compressors for general shop use, the choice will generally come down to a piston compressor or a helical-screw compressor. Piston compressors tend to be less expensive than screw compressors, require less sophisticated maintenance, and hold up well under dirty operating conditions. They are much noisier than screw compressors, however, and are more susceptible to passing oil into the compressed air supply, a phenomenon known as “carryover.” Because piston compressors generate a great deal of heat in operation, they have to be sized according to a duty cycle—a rule of thumb prescribes 25% rest and 75% run. Radial-screw Variable Frequency Water Lubricating Oil-Free Screw Compressor can run 100% of the time and almost prefer it. A potential problem with screw compressors, though, is that oversizing one with the idea of growing into its capacity can lead to trouble as they are not particularly suited to frequent starting and stopping. Close tolerance between rotors means that compressor needs to remain at operating temperature to achieve effective compression. Sizing one takes a little more attention to air usage; a piston compressor may be oversized without similar worries.     An autobody shop which uses air constantly for painting might find a radial-screw compressor with its lower carryover rate and desire to run continuously an asset; a general auto-repair business with more infrequent air use and low concern for the cleanliness of the supplied air might be better served with a piston compressor.     Regardless of the compressor type, compressed air is usually cooled, dried, and filtered before it is distributed through pipes. Specifiers of plant-air systems will need to select these components based on the size of the system they design. In addition, they will need to consider installing filter-regulator-lubricators at the supply drops.     Larger job site compressors mounted on trailers are typically rotary-screw varieties with engine drives. They are intended to run continuously whether the air is used or dumped.     Although dominant in lower-end refrigeration systems and air compressors, scroll compressors are beginning to make inroads into other markets. They are particularly suited to manufacturing processes that demand very clean air (class 0) such as pharmaceutical, food, electronics, etc. and to cleanroom, laboratory, and medical/dental settings. Manufactures offer units up to 40 hp that deliver nearly 100 cfm at up 145 psi. The larger capacity units generally incorporate multiple scroll compressors as the technology does not scale up well once beyond 3-5 hp.     If the application involves compressing hazardous gases, specifiers often consider diaphragm or sliding-vane compressors, or, for very large volumes to compress, kinetic types.

Publish Date: 2021/09/05