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- Создано: 16-12-21
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Woofers, Tweeters, and Crossovers: Understanding Loudspeakers
Описание: Woofers, Tweeters, and Crossovers: Understanding Loudspeakers Loudspeakers are critical to any audio system. From tweeter speakers to woofer speakers, loudspeakers are the components that provide movies, music, and sports with sounds that are often taken for granted. Microphones convert sound into electrical impulses that can be recorded onto some form of storage media. Once captured and stored, it can be reproduced at a later time or place. Hearing recorded sound requires a playback device, an amplifier, and, most critically, a loudspeaker. What Is a Loudspeaker? A loudspeaker is a device that converts electrical signals into sound as the result of an electro-mechanical process. Speakers typically incorporate the following construction: A metal frame or basket, within which all the speaker components are placed. A diaphragm that pushes air out through vibration. The vibration patterns reproduce the desired sound waves received by your ears. The diaphragm is often referred to as the cone. Although a vibrating cone is commonly used, there are some variations, which are discussed below. An outer ring of rubber, foam, or other compatible material, referred to as a surround. Not be confused with surround sound or surround speakers, the surround holds the diaphragm in place while providing enough flexibility to vibrate. Additional support is provided by another structure, referred to as a spider. The spider makes sure that the vibrating speaker diaphragm and surround do not touch the outer metal frame. A voice coil wrapped around an electromagnet is placed at the back of the diaphragm. The magnet or voice coil assembly provides the power to make the diaphragm vibrate according to the received electrical impulse patterns. Cone speakers also have a little bulge that covers the area where the voice coil is attached to the diaphragm. This is referred to as the dust cap. The speaker (also referred to as a speaker driver or driver) can now reproduce sound, but the story doesn't end there. The speaker must be placed inside an enclosure so that it performs well and looks aesthetically pleasing. Most of the time, the enclosure is some type of wood box. Other materials, such as plastic and aluminum, are sometimes used. Instead of a box, speakers can come in other shapes, such as a flat panel or sphere. Not all speakers use a cone to reproduce sound. Some speaker makers, such as Klipsch, use horns in addition to cone speakers. Other speaker makers, most notably Martin Logan, use electrostatic technology in speaker construction. Still others, such as Magnepan, use ribbon technology. There are also cases where the sound is reproduced by non-traditional methods. Full-Range, Woofers, Tweeters, and Mid-Range Speakers The simplest loudspeaker enclosure contains only one speaker, which reproduces all the frequencies sent to it. However, if the speaker is too small, it may only reproduce higher frequencies. If it is medium-sized, it may reproduce the sound of a human voice and similar frequencies well and fall short in the high and low-frequency range. If the speaker is too large, it may do well with lower frequencies and, perhaps, mid-range frequencies, and may not do well with higher frequencies. The solution is to optimize the frequency range that can be reproduced by having speakers of different sizes inside the same enclosure. Woofer speaker A woofer is a speaker that is sized and constructed so that it can reproduce low and mid-range frequencies. Woofers do most of the work in reproducing the frequencies you hear, such as voices, most musical instruments, and sound effects. Depending on the size of the enclosure, a woofer can be as small as 4 inches in diameter or as large as 15 inches. Woofers with 6.5-inch to 8-inch diameters are common in floor standing speakers. Woofers with diameters in the 4-inch and 5-inch range are common in bookshelf speakers. Tweeter speaker A tweeter is a specially designed speaker that is smaller than a woofer. It only reproduces audio frequencies above a certain threshold, including, in some cases, sounds that human ears cannot hear but only sense. There are ribbon tweeter, dome tweeter, and membrane tweeter, etc. Because high-frequencies are highly directional, tweeters disperse high-frequency sounds into the room so that the sounds are heard accurately. If the dispersion is too narrow, the listener has a limited amount of listening position options. If the dispersion is too wide, the sense of direction of where the sound is coming from is lost. These are the different types of tweeters: Cone: A smaller version of a standard speaker. Dome: The voice coil is attached to a dome that is made of fabric or a compatible metal. Piezo: Instead of a voice coil and cone or dome, an electrical connection is applied to a piezoelectric crystal, which in turn vibrates a diaphragm. Ribbon: Instead of a traditional diaphragm, a magnetic force is applied to a thin ribbon to create sound. Electrostatic: A thin diaphragm is suspended between two metal screens. The screens react to an electrical signal in such a way that the screens become out-of-phase. This alternately attracts and repels the suspended diaphragm, creating the needed vibration to create sound. Mid-Range Speaker and full range speaker A speaker enclosure may incorporate a woofer and tweeter to cover the entire frequency range. However, some speaker makers add a third speaker that further separates the low-range and mid-range frequencies. This is referred to as a mid-range speaker. 2-Way vs. 3-Way Enclosures that incorporate only a woofer and a tweeter are referred to as 2-way speakers. Enclosures that house a woofer, tweeter, and mid-range are referred to as 3-way speakers. The 3-way speakers may not always be better. A well-designed 2-way speaker can sound excellent, and a poorly-designed 3-way speaker can sound terrible. It's not only the size and number of speakers that matters. The sound quality also depends on the materials the speakers are constructed of, the enclosure's interior design, and the quality of the next needed component—the crossover. Crossovers You just don't throw a woofer and a tweeter into a box, wire them together, and hope it sounds good. When you have a 2-way speaker or a 3-way speaker in your cabinet, you also need a crossover. A crossover is an electronic circuit that assigns the appropriate frequency range to different speakers. For example, in a 2-way speaker, the crossover is set at a specific frequency point. Any frequencies above that point are sent to the tweeter, while the remainder are sent to the woofer. In a 3-way speaker, a crossover can be designed so that it has two frequency points—one for the point between the woofer and mid-range, and another for the point between the mid-range and tweeter. The frequency points of the crossover vary. A typical 2-way crossover point might be 3kHz (anything above goes to the tweeter, anything below goes to the woofer). Typical 3-way crossover points might be 160Hz to 200Hz between the woofer and mid-range, and then the 3kHz point between the mid-range and tweeter. Passive Radiators and Ports A passive radiator looks like a speaker. It has a diaphragm, surround, spider, and frame, but it is missing the voice coil. Instead of using a voice coil to vibrate the speaker diaphragm, a passive radiator vibrates in accordance with the amount of air the woofer pushes inside the enclosure. This creates a complementary effect in which the woofer provides the energy to power itself and the passive radiator. Although not the same as having two woofers connected directly to the amplifier, the combination of the woofer and the passive radiator produces more effective bass output. This system works well in smaller speaker cabinets, as the main woofer can be pointed outward towards the listening area, while the passive radiator can be placed on the back of the speaker enclosure. An alternative to a passive radiator is a port. The port is a tube placed on the front or rear of the speaker enclosure so that the air pumped out by the woofer is sent through the port, creating a similar complementary low-frequency enhancement as a passive radiator. A port must be a specific diameter and tuned to the characteristics of the enclosure and woofer that it complements. Speakers that include a port are referred to as bass reflex speakers. Subwoofer speaker A subwoofer reproduces very low frequencies and is used mostly in home theater surround sound applications and high-end audio. Examples where a subwoofer is desired include reproducing specific low-frequency effects (LFE), such as earthquakes and explosions in movies, and for music, pipe organ pedal notes, acoustic double bass, and tympani. Most subwoofers are powered. That means that unlike traditional speakers, subwoofers have a built-in amplifier. On the other hand, like some traditional speakers, subwoofers may employ a passive radiator or port to enhance low-frequency response. The Bottom Line Loudspeakers reproduce recorded sound so that it can be heard in a different time or place. There are several ways to design a loudspeaker, including bookshelf and floor standing size options. Before you buy a loudspeaker or a loudspeaker system, do some critical listening with content you are familiar with. CDs, DVDs, Blu-ray and Ultra HD Blu-ray Discs, or vinyl records would all work.
Дата Публикации: 16-12-21
Pee Pad Training: Is It a Good Idea?
Описание: Pee Pad Training: Is It a Good Idea? Congratulations on your new puppy! Puppyhood is a fun stage of your dog's life, where you'll get lots of licks and laughs, but there's also lots of work to do to set your puppy up for success. You want to make sure you show your pup how to be a well-behaved member of the family, and, if you value your floors and your sanity, it starts with potty training. You might be considering using puppy pee pads to help housebreak your pup. In my professional opinion, I prefer to set a puppy up for success from the beginning and teach them to only go potty outside. However, if it's difficult to provide frequent potty breaks for your puppy due to your schedule, personal circumstances, or living situation (especially if you're an apartment-dweller), pee pads or a dog porch potty can be a useful tool. Pee pad training can also be used for young, unvaccinated litters of puppies, or for older pets who are sick or might otherwise have trouble getting outside (e.g., arthritis, neurologic problems). Below is a review of some of the pros and cons of pee pad training for your puppy. Pros of Pee Pet Pad Training Can be convenient: You can place pee pads anywhere. In many cases, it may also be quicker and more easily accessible to get to a pee pad, like a dog diaper, rather than outside or all the way down the elevator, before an accident happens. For example, if you are mobility impaired or live on an upper floor of a tall apartment building, it's much easier to get your puppy to their pee pad area than make the long trip downstairs to get them outside. Easy clean-up: Like a diaper, pee pads soak up the mess and you can simply toss them in the trash. Or you can buy reusable, washable ones. Creates an appropriate potty spot: Pee pads can encourage your puppy to potty in the right place with a built-in attractant. You can also purchase potty attractant spray to use on your dog's porch potty, and even use it to encourage your dog to go potty in certain parts of the yard over others. Pee pads or dog litter boxes create an appropriate potty area in your puppy's long-term confinement zone, helping your puppy learn to go to the bathroom away from their sleeping area. Weather friendly: For all those times when it's just downright nasty out and the idea of taking your dog out to potty makes you want to cry, pee pet pads give your dog an indoor bathroom option. Some pups have a hard time going potty outside in inclement weather because they're uncomfortable or distracted. No trip outside necessary for pee pad trained pups. Pro Tip: If you're using potty pads or a porch potty, or pet wipes, you'll want somewhere convenient to throw away any waste. Instead of making the trek to the trash can every time you pick up your puppy's poo, invest in a small dog waste station with deodorizer, like this one from PetFusion. I have one on my patio and love that I don't have to carry the poo bags all the way back to the dumpster behind our townhome. It has a locking lid and includes a charcoal filter that helps reduce odor, and it's lightweight and portable – making trips to toss the poo in the outdoor garbage less frequent! Cons of Training Your Puppy to Use Pee Pads Anything could be a pee pad: Teaching your pup to pee on a thin paper underpad may also teach them that it's okay to pee on similar items. They might consider the newspaper you tossed on the floor as fair game for a potty spot. Some dogs who use pee pads generalize to going to the bathroom on any square mat or rug in the house. Watch out when you step out of the shower! Set-up for outdoor potty training failure. By allowing your puppy to eliminate indoors while also trying to train them to go potty outside, you are sending mixed messages. This confusion can delay the desired habit of holding it until they can go outside. Plus, your puppy could become dependent on their pee pads. It can be a long process to transfer your dog's potty habits from indoor pee pads to only outdoors. To learn about the process and get started, check out my article "Training Your Dog to Stop Using Pee Pads." Chewing and shredding risk: Puppies like to explore the world with their mouths. Placing pee pads on the floor may just be an open invitation for your pup to go into shredding (and swallowing) mode. Pee pads = comfy resting spot! Many puppies make a bed out of their potty pads. Not only does this work against the natural instinct to not potty where they rest (often delaying potty training success), but it also means that they get dirty and smelly from laying down in their own waste. Tasty snack: Some puppies like to eat their own stool (a habit known as coprophagia) if given the chance. Using potty pads provides them the opportunity to practice this behavior because they are not being supervised as they would be on a leashed potty break. You can also use a poop bag. Missing out on fresh air and socialization experiences. While pee pad training can be more convenient and can keep you both warm and dry when the weather isn't cooperating, one of the great joys and benefits of having a dog is that you get outside and enjoy the fresh air more often. These outdoor excursions also give you the opportunity to meet other people or dogs in your community. Pee pad training can deprive your pup of the benefits of socialization.
Дата Публикации: 16-12-21
Face masks
Описание: Face masks What are face masks? Face masks such as cloth or fabric masks act as a simple barrier and work as "source control". "Source control" refers to preventing the wearer's respiratory droplets from travelling into the air and onto other people when the person wearing the mask coughs, sneezes, talks etc. These are not suitable for use during medical and surgical procedures in healthcare facilities, where exposure and risk of transmission of infection is higher. These masks may be used by the general public and in community settings. Please refer to MOH's guidance and FAQs on the use of masks. Face masks are not regulated as medical devices under the Health Sciences Authority (HSA). Therefore, the quality and effectiveness of face masks are not regulated by HSA. How to choose a face mask? For greater effectiveness, choose face masks that have good filtration capability, along with disposable shoe cover, disposable PE sleeve cover, and disposable protective coverall. Examples of such masks include those distributed by the People's Association and Temasek Foundation. When selecting a face mask, look for the following specifications: Masks with at least 2 to 3 layers of fabric. As a general guide, the material should not be see-through when held against light. Layers should preferably be made with different fabrics, including: Water-repellant outer layer Middle filter layer to remove particulates – this can be disposable filter inserts Absorbent inner layer to absorb droplets from wearer's mouth Fabrics with better filtering efficiency Fabrics with enough permeability to allow breathing Appropriate fit around the face and chin, with complete coverage of the nose and mouth, to prevent leakage of exhaled droplets Do not choose masks with exhalation valves, as these allow the escape of exhaled droplets from the wearer and exposes others to the risk of infection. Are face masks useful? Face masks with good filtering efficiency help prevent people who have COVID-19 from spreading the virus to others by acting as a "source control". Wearing a mask in public places limits exposure to respiratory droplets and large particles and reduces the risk of community spread of infection. This is especially relevant for asymptomatic or pre-symptomatic infected wearers who feel well and may be unaware that they are infectious. These mask, like disposable bouffant cap, are particularly useful in public settings (e.g. when using public transport) when strict adherence to safe distancing may be challenging. Surgical masks What are surgical masks? Surgical masks are medical masks that offer both "source control" and protection for the wearer against exposure to splashes and sprays of infectious material from others. Therefore, in situations where an individual is in contact with an infected or a potentially infected individual (e.g. visiting a clinic for consultation, patient care givers) a surgical mask is recommended. Surgical masks offer high filtration efficiency, adequate breathability and reasonable fluid penetration resistance. Their performance characteristics are tested according to a set of standardised test methods based on international standards such as ASTM F2100, EN 14683, Singapore Standard SS 669 series or equivalent to verify that they meet prescribed requirements for bacterial filtration efficiency (at least 95%), breathability, splash resistance etc. These masks, which are used during medical and surgical procedures in healthcare settings, are regulated as medical devices under HSA. Are locally manufactured surgical masks safe for use? Local surgical mask manufacturing facilities are required to be licensed by HSA. Prior to licensing, these facilities have been subject to virtual inspections and desktop audit by HSA to ensure they meet reasonable standards of manufacturing quality. View list of surgical masks from local manufacturers that have been licensed by HSA All surgical masks manufactured by these licensed facilities are also required to comply with relevant international standards such as ASTM F2100, EN 14683, Singapore Standard SS 669 series, or equivalent and are required to be tested to meet a minimum bacterial filtration efficiency of 95% or higher. To improve access to good quality and safe masks, HSA has worked closely with companies who applied to set up local manufacturing facilities for surgical masks. We have supported these facilities to comply with international standards of manufacturing quality and ensuring that their masks are tested to be safe and effective. To date, we have licensed 26 mask manufacturing facilities to meet our local demand for surgical masks. Non woven patient gown and disposable lab coat are also needed. Simple rules for effective masks usage Dos Ensure that you consistently use and wear an appropriate mask (with good filtration efficiency), according to its purpose as described on the instructions. Practise proper removal of used and contaminated masks to prevent the spread of viruses to your hands, face and other contact surfaces. Touch only the straps and not the surface of the mask when removing it. You should wash your hands after disposal of a used mask. Reduce the amount of talking when wearing a mask. These actions will lower the amount of condensation produced within the mask and extend its effective life. To ensure effectiveness, change masks if soiled or wet. For reusable mask, follow the manufacturer's instructions on washing, and replace once it is used beyond the recommended number of uses. Don'ts Do not reuse masks as they are contaminated once used.
Дата Публикации: 16-12-21
Types of Sewing Machines and their Uses
Описание: Types of Sewing Machines and their Uses Industrial sewing machines differ from traditional consumer sewing machines in many ways. An industrial sewing machine with embroidery machine parts is specifically built for long term, professional sewing tasks and is therefore constructed with superior durability, parts, and motors. Whereas traditional sewing machines might include nylon or plastic gears, an industrial sewing machine's gears, connecting rods, housings, and body are typically constructed from high-quality metals, such as cast iron or aluminum. Beyond that, industrial sewing machines are made to handle thick materials such as leather, produce faster stitch rates, and incorporate stouter, more positive feed components than do their consumer equivalents. Types of Industrial Sewing Machines With regard to these types of industrial sewing machines, the primary differentiation between them is based on the design of the bed. These four different sewing machine bed styles and their uses are as follows: Flatbed: The most common type, these machines resemble traditional sewing machines in that the arm and needle extend over the flat base of the machine. Workers typically use this machine for sewing flat pieces of fabric together. Some type of fabric feed mechanism is usually housed in the bed (see below). Cylinder-bed: These machines feature a narrow, cylindrical bed as opposed to a flat base. This allows the fabric to pass around and under the bed. Workers employ the cylinder-bed machine for sewing cylindrical pieces such as cuffs, but it is also useful for bulky and curved items such as saddles and shoes. Post-bed: These machines feature bobbins, feed dogs, and/or loopers in a vertical column that rises above the flat base of the machine. The height of this column can vary depending on the machine and its application. Applications that make access to the sewing area difficult, such as attaching emblems, or boot or glove making, utilize the post-bed machine. Off-the-arm: The least common group, these machines extend a cylindrical bed out from the back of the machine perpendicular to the direction taken by the bed of the cylinder-bed machine. This allows for long runs of tubular goods, such as the inseams of trousers, and is useful for sewing sleeves and shoulder seams. Other special-purpose sewing machines exist, as well. Portable and fixed electric units are often employed for closing large sacks of agricultural products, dog food, etc. Bookbinders use special machines in their operations. Carpet installers also use special machines for binding carpet. Embroidering and monogramming machines are used for textile customization and decorating and are often program-controlled. Special long arm machines are made for sailmakers and purpose-built machines are available for cobblers. Sewing Machine Feeds Different industrial sewing machines offer several ways to feed the material. Typically, industrial sewing machines that deliver numerous feed capabilities are more expensive. The main types of feed mechanisms are: Drop feed: The feed mechanism lies below the machine's sewing surface. This is probably the most common feed type. Toothed segments called feed dogs lift and advance the fabric between each stitch, with the teeth pressing upwards and sandwiching the material against a presser foot. Needle feed: The needle itself acts as the feed mechanism, which minimizes slippage and allows workers to sew multiple layers of fabric. There is also super multi head lace embroidery machine. Walking foot: The immobile presser foot is replaced with a foot that moves with the feed, which allows easier performance on thick, spongy or cushioned materials. Puller feed: The machine grips and pulls straight-seamed material as it is sewn and can perform on large, heavy-duty items such as canvas tents. Manual feed: The feed is controlled entirely by the worker, who can do delicate, personal work such as shoe repair, embroidering, and quilting. On industrial sewing machines, it is sometimes necessary to remove the feed dogs to obtain a manual feed. The application of an industrial sewing machine is also an important factor to consider. For example, some machines come with an automatic pocket setter, while others include pattern programmability or electronic eyelet buttonholers. Furthermore, the strength and design of the machine needs to complement the type of material being sewn. Higher quality machines will likely be necessary for medium to heavy materials, such as denim, while base level industrial machines may be adequate for lighter materials, such as cotton. Other Considerations A particular machine's available stitch types can vary. There are several dozen distinct types of stitches, each requiring between one and seven threads. Plain, or straight stitches are the most commonly used stitches in industrial sewing and include lock, chain, overlock, and coverstitch. Sailmakers, on the other hand, use zig-zag stitching to better tolerate seam loading between sail panels. Yet another important feature is the size and speed of the industrial sewing machine. More expensive machines will be able to sew more stitches per minute. Larger machines provide a larger clearance area under the foot and bigger bed size. Also, different embroidery machine series has different features. Many industrial machines are sold without motors and can be operated with either clutch motors or servomotors, depending on the user's needs. Clutch motors run constantly and power to the machine is transmitted by depressing a foot treadle to actuate the clutch. Servomotors run on demand and are speed controllable as well, much as are home sewing machines. Both motor types are available for 120 or 240 vac power. Raising of the presser foot is often done with a knee paddle to allow the operator full use of both hands. Although many home machines are able to do a wide variety of operations, production sewing often uses machines that are set up for specific tasks such as bar tacking, buttonhole making, etc. Machines for tailors and seamstresses are likely to be capable of a fuller range of operations.
Дата Публикации: 16-12-21
What You Need to Know about Dietary Supplements
Описание: What You Need to Know about Dietary Supplements Dietary Supplements can be beneficial to your health — but taking supplements can also involve health risks. The U.S. Food and Drug Administration (FDA) does not have the authority to review dietary supplement products for safety and effectiveness before they are marketed. You've heard about them, may have used them, and may have even recommended them to friends or family. While some dietary supplements are well understood and established, others need further study. Read on for important information for you and your family about dietary supplements. Before making decisions about whether to take a supplement, talk to your healthcare provider. They can help you achieve a balance between the foods and nutrients you personally need. What are dietary supplements? Dietary supplements include such men health ingredients as vitamins, minerals, herbs, amino acids, and enzymes. Dietary supplement ingredients are marketed in forms such as tablets, capsules, softgels, gelcaps, powders, and liquids. What are the benefits of dietary supplements? Some supplements can help assure that you get enough of the vital substances the body needs to function; others may help reduce the risk of disease. But supplements should not replace complete meals which are necessary for a healthful diet – so, be sure you eat a variety of foods as well. There are apple extract, green tea extract, marigold extract, etc. Unlike drugs, supplements are not permitted to be marketed for the purpose of treating, diagnosing, preventing, or curing diseases. That means supplements should not make disease claims, such as "lowers high cholesterol" or "treats heart disease." Claims like these cannot be legitimately made for dietary supplements. Are there any risks in taking supplements? Yes. Many supplements contain active ingredients that have strong biological effects in the body. This could make them unsafe in some situations and hurt or complicate your health. For example, the following actions could lead to harmful – even life-threatening – consequences. Who is responsible for the safety of dietary supplements? FDA is not authorized to review dietary supplement products for safety and effectiveness before they are marketed. The manufacturers and distributors of dietary supplements are responsible for making sure their products are safe BEFORE they go to market. Natural sweeteners come from flowers and plants directly, with little processing. Examples include stevia, monk fruit extract, and yacon syrup. Many people are turning away from refined table sugar and high-fructose corn syrup, looking for more healthful options. They may be making wider changes, such as following a keto diet, which can help some people avoid unnecessary calories and lose weight. Also, people with conditions such as diabetes must be aware of the types of sweeteners that they use, as many affect blood sugar. While natural sweeteners can be a better alternative to refined sugars, some are less healthful than many people believe. Anyone considering switching sweeteners for health reasons may benefit from discussing options with a dietician or doctor. Stevia Stevia rebaudiana is a plant in the sunflower family and is native to parts of South America, and it can make stevia leaf extract. The leaves contain two primary compounds — one is extremely sweet, while the other is very bitter. Manufacturers extract the sweet compounds from the plant to produce stevia. These compounds can be up to 300 times as sweet as table sugar, and stevia extracts are naturally calorie free, making the sweetener a popular choice. However, some people feel that stevia is not truly "natural" because of the amount of processing required to produce the white, powdery stevia product in many stores. A person can purchase stevia leaves and leaf powder, though these may contain bitter as well as sweet compounds, and they are less widely available. Monk fruit Monk fruit, native to southern China, is another alternative sweetener. The fruit contains compounds called mogrosides, which can be 150–200 times as sweet as sugar, according to the International Food Information Council Foundation. However, although they are sweet, these compounds do not raise blood sugar in the same way that other sweeteners do. Monk fruit powder and extracts also contain no calories or carbohydrates. Yacon syrup Yacon syrup is sticky nectar harvested from the yacon plant, which is also native to parts of South America. The syrup is dark brown and resembles molasses. Yacon syrup contains calories. However, it is high in soluble fibers called fructooligosaccharides, which have just half the calories of regular sugar, as a review in the journal BMC MedicineTrusted Source notes.
Дата Публикации: 16-12-21
Benefits of Having A Beer Keg In Your Kitchen
Описание: Benefits of Having A Beer Keg In Your Kitchen Drinking beer in moderation can provide several health benefits. For one, beer can actually protect your heart as you age and decrease the risks of cardiovascular diseases. Beer can also strengthen your bones, improve memory, and reduce stress. While you can always buy a bottle of ice-cold beer, buying a beer keg in your kitchen can be more convenient, especially if you're running a pub. Beer kegs work by protecting its content from the outside environment, allowing compressed gas to push its content out, and providing an exit for the content to flow freely. Beer kegs come in different shapes and sizes but all of these contain the same mechanism. Benefits of Having A Beer Keg In Your Kitchen 11/24/2019 By Guest Blog Share This Article Benefits of Having A Beer Keg In Your Kitchen Drinking beer in moderation can provide several health benefits. For one, beer can actually protect your heart as you age and decrease the risks of cardiovascular diseases. Beer can also strengthen your bones, improve memory, and reduce stress. While you can always buy a bottle of ice-cold beer, buying a beer keg in your kitchen can be more convenient, especially if you're running a pub. Beer kegs work by protecting its content from the outside environment, allowing compressed gas to push its content out, and providing an exit for the content to flow freely. Beer comy kegs come in different shapes and sizes but all of these contain the same mechanism. By having a beer keg in your kitchen, you'll be able to enjoy the following benefits: 1. Easier Clean-Ups Parties can be utilized as a platform to socialize with other people and relieve yourself from stress. Parties can be fun as it breaks the monotony of working five days a week. However, when you're the host, it might not be as fun as you'll have to clean the space after the party. The maxim that states, "The more, the merrier," might be apt for parties, but on the other side of the coin, more guests can translate to more cleanup time. Beer kegs are easier to clean, making it a favorite among parties. When you have one, you won't have to strain yourself picking up several bottles or cans of beers after a party. You can store and serve beer kegs using one, two, or three door kegerators installed conveniently behind your bar and not to worry about picking up a single can or bottle of beer. By investing in a beer keg, you can ensure that all of your upcoming parties will be memorable for everyone, especially to you as a host. 2. Eco-Friendly There are a lot of elements involved in the packaging of a single beer bottle. Bottles, labels, and caps are used. When buying in bulk, these will be packed into cases or cartons. These items might be small, but over time, it can eventually accumulate and cause damage to the environment and the animal's habitat. Beer kegs are eco-friendly as you won't generate any packaging waste from beer. Beer wine kegs are designed to hold large amounts of liquid that are usually equivalent to at least 25 bottles of beer. There is also yeast keg. By having beer kegs in your kitchen, you won't create excessive waste as there are no bottles and packages to throw away. The longer you use beer kegs, the more significant your contribution will be in taking care of the environment. 3. Prevents Loss Regardless of the brand and quantity, buying bottles of beer can incur costs from your pocket. When hosting parties, you'll likely spend hundreds of dollars to ensure that all of your guests can drink beer. Since you've spent money on buying booze, accidentally dropping a single bottle of beer is one of the last things you want to happen. This situation will require you to buy more beer, which can result in more costs. To prevent losing or wasting any bottles of beer, invest in a beer cleaning keg as soon as possible. Your one-time payment of buying a beer keg will go a long way as it can prevent loss through the following: No bottles used: Buying bottles of beer and storing them in your fridge can be convenient. However, beer bottles are made from fragile glass. Mishandling a single bottle can lead to breakage and spillage. When you buy a beer US keg, you don't need to worry about this problem because this specialized barrel doesn't use any bottles. Beer kegs eliminate the risks of breakage and spillage. Improved shelf life: Beers will usually spoil one day after opening it. When you open the beer, the air gets in and oxidizes the content. By using a beer keg, the shelf life of the beverage can improve as it doesn't come in contact with the air. Since beer kegs are air-tight, you can ensure that the quality of the beverage will be the same from the first to the last glass. 4. Reduces Cost As mentioned, buying beer will always entail costs. The more bottles or cans you'll buy, the more money you'll have to spend. But, when you buy a beer keg, you'll be able to reduce your costs because this equipment can protect your beverage in a lot of ways. By preventing beer bottles from breaking and improving the shelf life of its content, you can be sure that you won't have to make any repeat purchases. Aside from this, beer kegs can become a cost-effective investment in the long run as you won't have to buy individual bottles or cans of beers. Because a beer keg allows you to store large quantities of beer, you can directly buy from breweries. This purchase will entail lesser costs because there aren't any middlemen and packaging involved. Choose Carefully Sure, having a beer keg in your kitchen might be a smart investment, but buying one hastily can lead to stress and costs. Before deciding which beer keg to buy, take the time to consider the keg's style, size, and whether you're going to buy new or used. The more careful you are in buying, the higher the chances you'll have in buying the perfect beer keg for your needs and budget.
Дата Публикации: 16-12-21
A COMPLETE GUIDE TO STORAGE RACK SYSTEMS
Описание: A COMPLETE GUIDE TO STORAGE RACK SYSTEMS INTRODUCTION A storage rack or racking is a structure that consists of at least two upright (vertical) frames, horizontal beams, and some form of decking (bars, panels, meshes or none) in order to store goods and materials. Storage rack is an essential component to material handling as it allows you to maximize the height space available in your storage space, without subjecting your goods to load crushing due to stacking. In this guide, we at SWL help you understand the various types of storage shelves racks and identify which is the one you truly need for your storage space, from a neutral point of view. Fundamentally, most storage racking systems fall under these three broad categories: Light Duty Racking System, Medium Duty Racking System, Heavy Duty Racking System. LIGHT DUTY RACKING SYSTEM Light Duty Rack is designed for the sole purpose of hand-loaded storage, rather than using a machinery like reach truck or forklift. The loading capacity per tier varies between manufacturers but in general, Light Duty Racks can withstand between 80 to 250KG per tier, assuming uniformly distributed load (UDL). These attributes make Light Duty Racking Systems best suited for lightweight storage in homes, offices, SOHOs or commercial warehouses that deal with ecommerce and small FMCG. The two common types of Light Duty Racks in the market right now are Bolt & Nut Racks and Boltless Racks. Bolt & Nut Racks were very popular in the 1980s to 2000s as they are customizable to fit different kinds of space sizes. However, once fixed and bolted, it is hard to adjust the Shelf Levels or Tiers. Due to the additional components required to bolt the structure together, Bolt & Nut Racks are often very heavy and immobile, making relocation a hassle. Boltless Rack is a recent innovation and became popular during the early 2000s, when ecommerce started to take off and warehouse logistics realized that they needed versatile and modular storage racking systems to adapt to the ever-changing good sizes. Boltless Racks are typically set up by connecting the horizontal beams to upright frames via connector hooks and catches, instead of bolting. The decking is then placed on top of the horizontal beams in order to distribute any load towards the weight-bearing beams. This modular design makes Boltless Rack Systems versatile and adaptable to a wide variety of storage goods. However, a downside of the boltless feature is that Boltless Racks may feel flimsy and shaky, when there is no load on it. Another downside is that they often only come in standard sizes and offer little to no customization to its sizing. Regardless of which type of Light Duty Racking Systems, they often come in two types of decking – wooden boards (MDF/HDF/Plywood) or metal shelves. MEDIUM DUTY RACKING SYSTEM Medium Duty Rack is also designed for the sole purpose of hand-loaded storage, rather than using a machinery like reach truck or forklift. The key difference is that Medium Duty Racks have better loading capacity per tier, often between the ranges of 300 to 800KG per tier (UDL), and has the ability to come as a Cantilever System. Due to its increased loading capacity, they tend to have longer horizontal beam lengths up to 2400mm long and deeper upright frame profiles up to 900mm deep. To withstand the higher loading capacity and larger surface, they minimally use 12mm HDF Board or 18mm Plywood as decking, to maintain cost-effectiveness. Using metal shelf decking is possible too but at the cost of nearly 4 times the price of its wooden counterparts. These attributes make Medium Duty Racking Systems best suited for commercial and industrial warehouses where heavier goods and components, such as automotive parts or stackable boxes, need to be stored. Medium Duty Racks are sometimes referred as Longspan Racking by certain manufacturers, including us. At SWL, we further break down Medium Duty Racking Systems into, Ideal Longspan Rack, where the loading capacity per tier is 300 to 500KG per tier (UDL) Longspan Rack, where the loading capacity per tier is 500 to 800KG per tier (UDL) HEAVY DUTY RACKING SYSTEM (PALLET RACKING SYSTEM) Heavy Duty Rack, or more commonly known as Pallet Racking, is a robust structure designed for palletized goods and heavy goods storage. These goods often require material handling machineries such as a reach truck or forklift to lift. As such, Pallet Racks have loading capacity per tier that ranges between 1000 to 3000KG per tier (UDL). It also boasts horizontal beam lengths up to 3600mm long and upright frame depth profiles up to 1200mm deep. 18mm or 25mm Plywood must be used as decking, in conjunction with Centre Support Bars, to withstand the high loading capacity and large surface. Likewise, using metal shelf decking is possible too but at the cost of nearly 4 times the price of its wooden counterparts. Pallet Rack is a versatile racking system that allows you to adopt it in various setups: STORAGE RACK SYSTEM FOR HOME, OFFICE AND SOHO The storage you require at home or office is lightweight and normally doesn't exceed 20KG per item. These items may be household or office supplies like a carton of beer cans, A4 paper boxes, clothing and food. In this case, the use of Boltless Rack Systems will be most effective. Depending on the size and shape of your storage space with warehouse mezzanine, Boltless Racks can be configured into L-Shape Boltless Racks to offer better corner accessibility, at the expense of a reduced loading capacity across the L-Shape tier. This is due to the connection of the extended L-Shape portion borrowing loading strength from the main Boltless Rack. Automated storage systems for home and office should be kept at an optimal height of around 2m and no higher than 2.5m for safety reason, as most modern homes and office may not allow securing of the storage structure to the wall. Keeping to the 2m optimal height allows an average person to be able to reach the topmost of a storage rack, without the use of ladder or stool and without climbing on the storage cantilever rack itself. In the event that the storage rack has to be around 2.3m – 2.5m high, do remember to use a short stool or platform to access the higher tiers, instead of climbing on the storage rack. CHOOSING THE RIGHT WAREHOUSE RACKING SYSTEM FOR YOUR WAREHOUSE It can be a daunting task to maximize space and improve efficiency within your storage space. A balance of space consumption and ease of order picking must always be considered. Here are some of the key factors to help you with choosing the right warehouse racking system for your warehouse. How heavy are your goods? Do you need machinery to store your goods? What aisle width is needed for your warehouse? What rack depth should I be choosing? HOW HEAVY ARE YOUR GOODS? If your goods can be hand carried and generally weighs no more than 20KG, Light Duty Boltless Rack systems will be sufficient for your storage needs. With loading capacity up to 200KG per tier, you can easily store 7 to 8 of such items on a tier. If your goods can be hand carried but weighs more than 20KG yet less than 80KG, it is recommended to venture into the Medium Duty Racking systems. With loading capacity up to 500KG per tier, this range of racking system is more suited for heavier items that often require two people to carry or a semi-electric pallet jack to load up. The Medium Duty Racking systems also offer better length and depth profiles for goods size bigger than 60cm x 60cm, in terms of length and width. DO YOU NEED A MACHINE TO STORE YOUR GOODS? If your goods cannot be hand carried and requires a machine such as reach truck or forklift to load, Heavy Duty Pallet Racking systems should be your only consideration. It is the only system that is designed for machine-loading, due to its roll-formed structure that provides high strength and durability, and is able to withstand accidental small impacts. The Heavy Duty Pallet Racking systems also offer ideal depth profiles to suit the commonly used pallet sizes. WHAT AISLE WIDTH IS NEEDED FOR YOUR WAREHOUSE? For Light Duty Boltless Rack systems with rack accessories and Medium Duty Racking systems, we recommend a range of 80 to 120cm of aisle width, if you only do hand-loaded storage, or mobile racks. An aisle width of 80cm is often considered minimally comfortable as it provides the user with ample walking and body-turning space, while holding a big carton box. It also allows the user to roll in your average trolley, single direction, when doing order picking or goods stuffing. If your warehouse requires two users to be able to use an aisle concurrently or to be able to turn a trolley within an aisle, 120cm aisle width will be ideal. Do note that the 80 to 120cm is only a recommended guide and by no means a must – in the event your warehouse uses special material handling tools that require a large aisle width, adjust accordingly and always provide at least 30cm of clearance to manoeuvre your material handling tool. For Heavy Duty Pallet Racking systems, the required aisle width depends on the following factors: Reach Truck/Forklift Overall Length, inclusive of body and fork length Load Length Turning Radius Clearance There is no definite formula to calculating ideal aisle width when it comes to the use of machinery. An estimation we often use at SWL is (Turning Radius + Load Length + 450mm). Meaning to say, if your machine has a turning radius of 1,950mm and your common pallet load length is 1,100mm, we will recommend an aisle width of 3,500mm. This is to ensure that your machine has sufficient space to turn your picked load out, without being obstructed by other load positions to its left or right. WHAT RACK DEPTH SHOULD I BE CHOOSING? For Light Duty Boltless Rack systems and Medium Duty Racking systems, we recommend that the rack depth should match as close as possible to the goods size. If your box is 45cm x 60 cm, either go for a rack depth of 50 or 60cm. If you intend to store your boxes double deep and the box size is 20cm x 23cm, you can go for a rack depth of 40 or 50cm. For Heavy Duty Pallet Racking systems, if you are mainly storing palletized goods, it is recommended to choose a rack depth that is 20cm smaller than your pallet load length. For example, if your pallet size is 110cm x 110cm, a rack depth of 90cm will be ideal. If your pallet size is 120cm x 120cm, a rack depth of 100cm will be ideal. This is because the horizontal beams of the Pallet Racks are the core load-bearing components and you want most of the weight of the palletized goods to be on them. A rack depth smaller than the pallet load length also gives your reach truck/forklift driver a comfortable leeway – 10cm to the front and back - to rest the pallets on the Pallet Rack beams, without being too precise.
Дата Публикации: 16-12-21
Lithium, cesium and rubidium salts
Описание: Lithium, cesium and rubidium salts First proposed in the 1970s and produced commercially by Sony in 1991, lithium batteries are now used in mobile phones, airplanes and cars. Despite several advantages which have lead them to increasing success in the energy industry, lithium ion batteries have some drawbacks and are a topic that elicits much discussion. But what exactly are lithium batteries and how do they work? What are lithium batteries made of? A lithium battery is formed of four key components. It has the cathode, which determines the capacity and voltage of the battery and is the source of the lithium ions. The anode enables the electric current to flow through an external circuit and when the battery is charged, lithium ions are stored in the anode. The electrolyte is formed of lithium salts, solvents and additives, and serves as the conduit of lithium ions between the cathode and anode. Finally there is the separator, the physical barrier that keeps the cathode and anode apart. Pros and cons of lithium batteries Lithium batteries have a much higher energy density than other batteries. They can have up to 150 watt-hours (WH) of energy per kilogram (kg), compared to nickel-metal hydride batteries at 60-70WH/kg and lead acid ones at 25WH/kg. They also have a lower discharge rate than others, losing around 5% of their charge in a month compared to a nickel-cadmium (NiMH) batteries which lose 20% in a month. However, lithium batteries also contain a flammable electrolyte that can cause small scale battery fires. It was this that caused the infamous Samsung Note 7 smartphone combustions, which forced Samsung to scrap production and lose $26bn in market value. It should be noted that this has not happened to large scale lithium batteries. Lithium-ion batteries are also more expensive to produce, as they can cost nearly 40% more to produce than nickel-cadmium batteries. Cesium is an element. In its natural state, cesium salts is not radioactive. However, it can be made radioactive in the laboratory. People use both forms of cesium for medicine. Despite serious safety concerns, non-radioactive cesium is taken by mouth for treating cancer. This is sometimes called "high pH therapy." According to people who promote high pH therapy, taking cesium chloride by mouth reduces the acidity of tumor cells (raises their pH), which are described as very acidic. But these claims are not supported by science. There is no scientific research that indicates tumor cells differ in pH from normal cells or that cesium affects the pH of tumor or normal cells. Non-radioactive cesium is also used to treat depression. Healthcare providers sometimes treat cancer patients with radioactive cesium (cesium-137). In industry, radioactive cesium is also used in instruments that measure thickness, moisture, and liquid flow. How does it work? There isn't enough information to know how cesium might work. Some people who promote "high pH therapy" say cesium affects the pH (acidity) of cancer cells, but there's no scientific research to support this claim. Rubidium is a silvery-white and very soft metal — and one of the most highly reactive elements on the periodic table. Rubidium has a density about one and a half times that of water and is solid at room temperature, although the metal will melt if it's just a bit warmer, according to Chemicool. Like the other alkali metals (lithium, sodium, potassium, cesium and francium), rubidium reacts violently with water, oxidizes when reacting with oxygen, and ignites due to humidity in the air, so great care must be taken when working with the element. Scientists treat rubidium salts as a toxic element, according to Encyclopedia, although no known health effects of rubidium are known. History Rubidium was discovered by German chemists Gustav Robert Kirchhoff and Robert Wilhelm Bunsen in 1861 when they were observing the spectrum of the mineral lepidolite as it burned, according to Peter van der Krogt, a Dutch historian. The spectrum of rubidium showed off two dark red lines, and the scientists named the newly discovered alkali metal rubidium after the Latin word for "deep red." According to Chemicool, rubidium was extracted from the surrounding mineral by electrolysis. Approximately 330 lbs. (150 kilograms) of the lepidolite ore was needed in order to extract enough rubidium (about 1.5 percent of the mineral) in order to study its properties. The scientists found that rubidium was more electropositive (meaning that rubidium tended to form positive ions more readily, according to Encyclopedia) than potassium, another alkali metal and reacted violently with water releasing hydrogen.
Дата Публикации: 16-12-21
Cable Sheath Materials - What You Need to Know
Описание: Cable Sheath Materials - What You Need to Know Insulation and sheath are the components of a cable that protect the conductor. The insulation isolates the flow of electricity, and the sheath wraps around the outside of the cable to protect the conductors inside. The choice of material used for insulation and sheath can have a significant impact on the overall performance of a cable. The following will provide you with an overview of the most common materials used in cable manufacturing. PVC (Polyvinyl Chloride) – For internal installations.Polyvinyl Chloride (PVC) PVC is the most common and cheapest option for a given cable yarn design, it offers good flexibility, low cost and reasonable durability. It also offers good resistance to oil and water. The disadvantages are that some grades of PVC can weather badly and are susceptible to UV light. It can also give off poisonous halogen gases, toxic fumes and smoke when burnt. PE (Polyethylene) – For external installations. PE can be stiff and very hard, however low density PE (LDPE) is more flexible. If it's UV stabilized it offers excellent moisture and weather resistance. Often referred to as duct grade or weather resistant, high density PE sheath material (HDPE) can offer a good option for external or direct burial applications. LSF (Low Smoke & Fume) A modified PVC compound which can produce less HCI gas and smoke than PVC cables. However, LSF is a somewhat meaningless term, because it is PVC based it could still emit up to 22% Hydrogen Chloride (HCl) gas when burnt and give off black smoke. By way of comparison, standard PVC gives off up to 28% HCl. LSHF (Low Smoke Halogen Free) Also known as LS0H, LSZH sheath material (Low Smoke Zero Halogen) or sometimes OHLS (Zero Halogen Low Smoke). LSHF compounds are similar in appearance to PVC cables but behave very differently when exposed to fire. They do not give off significant amounts of toxic fumes or smoke and often their fire retardance is much better. LSHF cables are those which emit no more than 0.5% HCl when burned. Whilst more expensive than PVC/LSF cables LSHF provides improved building safety and are often specified for use in public buildings such as hospitals and airports etc. There is also CPR cable material. PTFE (Polytetrafluoroethylene) PTFE, or Teflon? to you and me, is a non-flammable, very flexible, non-toxic and environmentally safe material that can be used in demanding conditions. It can operate at temperatures from -75°C to +200°C, or up to +250°C short term. It is also unaffected by most fuels, oils and fluids. FEP (Fluorinated Ethylene Propylene) (Teflon? variant) It is a type of fluoropolymer that has very similar properties to PTFE such as operational temperatures and low-reactivity to chemicals. Rubber Natural rubber that ensures flexibility, even at sub-zero temperatures. Rubber is waterproof, chemical resistant, extremely flexible and retains it's flexibility over a wide range of temperatures. Due to it's high cost, synthetic rubber compounds are available to create more economical solutions which offer very similar performance. Neoprene Synthetic rubber that provides good oil and chemical resistance, tensile strength, as well as flexibility, even at low temperatures. Silicone For high or low temperature applications, operates from -50°C to +180°C. Excellent UV resistance and when exposed to fire does not produce any smoke or toxic gases. The soft material is however prone to damage and must be installed with care. PUR (Polyurethane) Offers good mechanical and chemical resistance. Its anti-kink characteristics make it ideal for high flexing automation applications. Depending on the blend, Polyurethane can be halogen free and flame retardant although not ideally suited for use in extreme temperatures due to the operating temperature range, typically between -40°C and +125°C.
Дата Публикации: 16-12-21
Advantages of Bamboo Materials for Bags
Описание: Advantages of Bamboo Materials for Bags Around 5 trillion plastic bags worldwide are consumed every year. Let's break that down. Five trillion plastic bags per year means: 160,000 plastic bags per second 700 plastic bags consumed per person Around 500 billion plastic bags in the ocean (based on the estimation that 10% of plastic waste becomes ocean plastic) Plastic bags are lightweight and cheap to produce, making them a popular choice among businesses and supermarkets. However, they're non-biodegradable, fragile (even the long-lasting plastic bags have a short life), and they're made from nonrenewable resources. These shortcomings mean that plastic bags are littering our landfills and oceans, killing our wildlife, and becoming a plight to the land. The thing is that, even though we know how bad plastic bags can be, it's hard to find a suitable substitute. As we seek out possible material alternatives for shopping bags, we should consider bamboo. What are bamboo bags? Bamboo bags are bags that are made from a textile using bamboo fiber. It's created by pulping the bamboo—turning it into mush—and separating bamboo fibers from that mush. Once separated, the fibers can be spun into yarn which is then woven into fabric. The fabric can then be used for shopping bags, backpacks, garment bags, and other items that require durable fabric. Bamboo bags are becoming a popular choice among businesses and shoppers for two main reasons: they look nice, and they're produced in an eco-friendly way. But bamboo bags offer so much more than that. The textile resulting from bamboo is a fantastic material that offers many unique benefits. What are the benefits of bags made from bamboo material? Bamboo bags have several benefits on individual, social, and environmental levels. It starts with the production of bamboo. Bamboo grows quickly, which makes it abundant and inexpensive. Unlike other plants and trees, bamboo requires no pesticides, it increases soil quality and decreases soil erosion, it requires low water use, and it boasts high CO2 absorption and high oxygen release. As a natural resource, Bamboo is one of the few plants that can actually make a positive difference in its cultivation. Once turned into a textile, bamboo offers plenty of advantages. Bamboo fabrication are naturally durable, biodegradable, and produce a soft material that's optimal for shopping bags. Compared to cotton, bamboo yields 50x more fiber. It's also more environmentally friendly to cultivate, it's cleaner, and it's economical. When it comes to reusable grocery bags, bamboo offers a shrewd choice. Disadvantages of bamboo as a textile Nothing comes without its disadvantages. As you decide which type of reusable bag you want your company to invest in, it's important to weigh the pros and cons. While the bamboo fabric is cleaner, more environmentally friendly, and more durable than many other textiles, it is more difficult to care for. It's inadvisable to machine wash bamboo fabric; the liquid detergent and the fact that the fabric will sit in water for a long period of time both serve to break down the textile and reduce its lifespan. It's highly recommended, therefore, that owners carefully follow the cleaning instructions that come with their bamboo product. Although bamboo bags can be washed—you may gently hand wash them or have them dry cleaned—they do require more care than other reusable bag options. However, this is a small price to pay for a good-looking, durable, and eco-friendly bag. BK Bamboo bags The bamboo bags offered by BK Bags offer all of the benefits of fabric made from bamboo: they're eco-friendly, durable, and biodegradable. The bamboo is sourced from China—the largest producer and exporter of bamboo—ensuring that the materials come from a place where bamboo is in abundance. With all of our products, we pay close attention to their production to verify that they truly help minimize our environmental footprints. Bamboo bags are clean, aesthetically pleasing, and ethically sourced. They offer many of the advantages of plastic bags without befouling our oceans and waterways. As you consider which plastic alternative you want to invest in, take a closer look at bamboo.
Дата Публикации: 16-12-21