Beautiful, durable, easy-care quartz is among the most popular countertop materials available—but it is pricey. If you’re considering quartz for your kitchen or bathroom, first get the 411 on this trendy topper before you buy. This complete countertop primer will set you up all of the necessary information on selecting and caring for quartz countertops, so you can make a smart decision and enjoy your work surface for years to come.

A visit to a kitchen showroom nowadays will show you a dazzling array of quartz countertop designs and patterns that remarkably mimic real marble and other natural stone. But quartz has come a long way! First appearing in Italy in the 1960s, these countertops were developed—by combining ground quartz particles with resins into a slab—as an alternative to stone that wouldn’t easily crack or break. While the resins added just enough flexibility to do the trick, early quartz countertops were a dull-looking cream and tan. Cutting-edge improvements in solid-surface technology have pure color quartz stone slab from functional to fabulous. With an abundance of finish choices and endless combinations of color and edge styles, you’ll likely find something stunning that suits your home.

Not only will you appreciate the look of quartz, you’ll find it remarkably easy to maintain—unlike marble and natural stone, which require a special sealant and can be finicky to care for. Quartz contains 90 to 94 percent ground quartz and 6 to 10 percent polymer resins and pigments, combined to produce a granite-hard slab that can duplicate the look of mesmerizing marble swirls or earthy natural stone, without the maintenance. Quartz also resists scratching and cracking to a greater degree than many natural countertops, ranking a “7” in hardness on the Moh’s scale (developed in 1822 by Friedrich Moh to rate mineral hardness). Marble, in comparison, ranks only a “3.”

A note to homeowners in the market to remodel: When exploring countertop options, make sure not to confuse quartz with quartzite. Quartz is engineered with pigments and resins, while quartzite is actually sandstone that, through natural metamorphosis, was exposed to intense heat, which caused it to solidify. Mined from large stone quarries and cut into solid slabs, quartzite is also available for countertops—but, unlike quartz, it must be sealed before use and again once or twice a year thereafter.

Thanks to its non-porous nature, quartz is mold-, stain-, and mildew-resistant, making it a breeze to keep not merely clean but also germ- and bacteria-free. Quartz also resists heat damage—up to a point. Manufacturers market quartz as able to withstand temperatures up to 400 degrees Fahrenheit (one reason it works well as fireplace surrounds). But “thermal shock” can result from placing a hot pan straight from the oven or stovetop onto a cold quartz countertop, which can lead to cracking or discoloring. And while quartz does resist staining because liquids can’t penetrate its surface, it’s not 100 percent stain-proof. Messes should be cleaned up quickly to best preserve quartz countertops’ original color.

The biggest downside to quartz, however, is cost. While a preformed or laminate countertop will set you back a few hundred dollars, quartz countertops cost between $70 to $100 per sq. ft., installed, comparable to the price of natural stone countertops. For a mid-size kitchen, you can easily spend a few thousand dollars for quartz.

If you’re planning a backyard kitchen, steer clear of quartz altogether. It’s not suitable for outdoor installation, as the sun’s UV rays can break down the resin binders and degrade the countertop, leading to fading and eventual warping.
With such a vast selection, making up your mind can be a challenge! So bring home a few quartz samples from a kitchen showroom before settling on a specific color or design. Under your own lighting, and against the backdrop of your cabinets and walls, you’ll be better able to choose a pattern and design that complements your kitchen décor. It helps to have a good idea of what you want your finished kitchen to look like before you buy. You can browse through design books at any kitchen center, or get ideas from show homes and home-design magazines and websites. As you plan, keep these points in mind:

Seams: If your counter is longer than 120 inches, or if it involves a complex configuration, Marble Look Quartz Stone Slab may have to be fabricated in more than one section, which means you’ll have one or more seams. Seams are typically less visible on dark-toned quartz but can be quite noticeable on light-toned or multicolor countertops, such as those with obvious veining or marbling patterns.
Thickness: Countertop thickness ranges from ½ inch to 1-¼ inch, depending on style, brand, and size. If you’re ordering a large countertop or want an elaborate edge design, the fabricator may suggest a thicker slab. If your heart is set on a thin countertop but your kitchen is large, expect to have one or more seams. Thickness also depends on custom features, such as integrated drain boards and elaborate edge profiles.

Design Details: Custom designs in a wide array of colors are available, from neutral grays, off-whites, and subtle tans to bold blues, bright yellows, and striking solid blacks. In addition to shade, you can choose from quartz made from small particles for a smooth appearance, or from larger grains for a flecked look. The surface can be sleek and glossy or feature a flecked, pebbled, embossed, or even suede appearance.

Edge Ideas: Custom edge profiles in complex designs bring distinction to your cook space but add to the final cost. You can opt for a bold square countertop edge, a chiseled raw-edge look, or select a softer, rounded bullnose corner. A reverse waterfall edge resembles the shape of crown molding and adds a touch of traditional elegance, while contemporary edges, including slanted, mitered, or undercut create the illusion of a thinner slab. Ogee (S-shape) is a popular edge design that fits just about any decor.

Bathroom Buys: Selecting a quartz countertop for a bathroom is slightly different from buying one for your kitchen. Bathroom vanities come in standard sizes, so you can purchase pre-made vanity countertops. Many come with pre-molded sinks or pre-cut holes to accommodate drop-in sinks. Bathroom vanity quartz countertops range from $400 to $1,000 depending on length, and installation for them is more DIY-friendly.

Professional installation is highly recommended for quartz countertops in kitchens, due to the custom nature of cabinet configuration and the weight of the slabs, which often require multiple workers just to lift. To protect your investment, installers should be certified to mount the specific brand of quartz you purchase. Many quartz countertops come with 15-year or even lifetime warranties, but often only when installed by certified professionals.

In this exclusive blog section of Alicante Surfaces, we try to share as much information and knowledge about the Quartz Countertops which we have gained in our past 20+ years of experience from the Tiles & Stones industry. Our blog articles are mainly focussed towards the Quartz Countertop Applications, it's usages and our exclusive range of products that we offer.
Material - Quartz slab or Engineered quartz stone slab is a composite material made of crushed stone bound together by a polyester resin. And we at Alicante procure the best Quartz Raw Materials for the manufacturing of grain quartz stone slab. Our Quartz slabs are highly popular and mainly used on the kitchen countertops.
Composition - Our manufactured premium quartz slabs consist of 93% quartz by weight and 7% resin. The main materials which are resins, which are available in various types, are used by quartz manufacturers as per their choice and needs. Stone is the major filler, although other materials like colored glass, shells, metals, or mirrors are also added to manufacture different kinds of designs.
Preference - Quartz slabs are becoming more and more popular day by day and are the preferred choice for Kitchen Countertop over Granite because of its anti-bacterial nature, less maintenance it requires, and its unique designs and colors which give marble look. 
Application - Alicante Quartz slabs are the perfect option for hectic kitchens and bathrooms. Also, our quartz countertops are extremely durable, practical, and low maintenance. Our products are tough, versatile, and easy to clean. The most common quartz application is kitchen countertops. They are hassle-free and very easy to clean and apply. 
Size & Color Range - We offer a wide range of sizes Starting from 140" x 77" known as the Super Jumbo Size, then we have got 126" x 63" with 2 CM & 3 CM thicknesses. Our Quartz slabs have the most choice in textures, tones, veins, and finishes. There are varieties of designs, sizes and collections are available in sparkling quartz stone slab. Our most famous range is Calacatta, Cararra, Pure White & Sparkle/Diamond Series.

With the current generation of smartphones and their much faster processors and vivid, high-resolution displays, and always-on connectivity, demands on battery performance are now higher than ever.
You may have noticed that, while you are on the road, you're quickly running out of juice. If you have this problem, portable batteries and PD fast charger than what may have come in the box with your device may be the solution.

But not all portable batteries are the same, even though they might use similar Lithium Polymer (LiPo) and Lithium-Ion (Lion) cells for capacity and look very much alike. Plus, modern smartphone hardware from Apple and various Android manufacturers support faster-charging rates than what was previously supported.

If you use the charger that comes in the box of the current-generation iPhone hardware, or if you buy just any portable battery pack on the market, you're going to be disappointed. Ideally, you want to match your charger, battery, and even the charging cable to the optimal charging speeds that your device supports.

There are three different high-speed USB charging standards currently on the market. While all will work with your device using a standard legacy charge mode, you will want to match up the right technology to optimize the speed in which you can top off your phone, tablet, or even your laptop. Let's start by explaining the differences between them.

Legacy USB-A 2.0 and 3.0 charging
If your Android device or accessory still has the USB Micro B connector (the dreaded fragile trapezoid that's impossible to connect in the dark), you can fast-charge it using an inexpensive USB-A-to-USB Micro B cable.

If the device and the 20W USB C PD fast charger white port both support the USB 2.0 standard (pretty much the least common denominator these days for entry-level Android smartphones), you can charge it at 1.5A/5V. Some consumer electronics, such as higher-end vape batteries that use the Evolv DNA chipset, can charge at 2A. A USB 3.0/3.1 charge port on one of these batteries can supply 3.0A/5V -- if the device supports it.

If you are charging an accessory, such as an inexpensive pair of wireless earbuds or another Bluetooth device, and it doesn't support either of the USB-A fast charging specs, it will slow charge at either 500mA or 900mA, which is about the same you can expect from directly connecting it to most PCs.

Many of the portable batteries on the market have both USB-C and multiple USB-A ports. Some of them have USB-A ports that can deliver the same voltage, while others feature one fast (2.4A) and one slow (1A).

So, you will want to make sure you plug the device into the battery port that can charge it at the fastest rate, if you're going to top off the device as quickly as possible.

USB Power Delivery
USB Power Delivery (USB PD) is a relatively new fast charge standard that was introduced by the USB Implementers Forum, the creators of the USB standard. It is an industry-standard open specification that provides high-speed charging with variable voltage up to 20V using intelligent device negotiation up to 5A at 100W.

It scales up from smartphones to notebook computers, provided they use a USB-C connector and a USB-C power controller on the client and host.

Batteries and 3 port PD fast charger that employ USB PD can charge devices up to 100W output using a USB-C connector -- however, most output at 30W because that is on the upper range of what most smartphones and tablets can handle. In contrast, laptops require adapters and batteries that can output at a higher wattage.

Apple introduced USB PD charging with iOS devices with the launch of the 2015 iPad Pro 12.9 and with OS X laptops in the MacBook Pro as of 2016. Apple's smartphones beginning with the iPhone 8 can rapidly charge with USB PD using any USB PD charging accessory; you don't have to use Apple's OEM USB-C 29W or its 61W power adapters. 

In 2019, Apple released an 18W USB-C Power Adapter, which comes with the iPhone 11 Pro and 11 Pro Max. Although Apple's charger works just fine, you'll probably want to consider a third-party wall charger for the regular iPhone 11 or an earlier model. The regular iPhone 11 and the iPhone SE only come with a 5W USB-A charger, which is woefully inadequate for getting your device charged up quickly.  And the current rumor mill seems to indicate that the iPhone 12 may not even ship with a charger in the box at all.

Fast-charging an iPhone requires the use of a USB-C to Lightning cable, which, until February 2019, needed Apple's OEM MKQ42AM/A (1m ) or MD818ZM/A (2m) USB-C to Lightning cables. Unfortunately, they're a tad expensive at around $19 to $35 from various online retailers such as Amazon. 

There are cheaper third-party USB-C to Lightning cables. I am currently partial to USB-C-to-Lightning cables from Anker, which are highly durable and MFI-certified for use with Apple's devices.

It should be noted that, if you intend to use your smartphone with either Apple's CarPlay and Google's Android Auto, your vehicle will probably still require a USB-A to USB-C or a USB-A-to-Lightning cable if it doesn't support these screen projection technologies wirelessly. You can't fast-charge with either of these types of cables in most cars, and there is no way to pass-through a fast charge to a 12V USB PD accessory while being connected to a data cable, either.

Qualcomm Quick Charge
Qualcomm's Snapdragon SoCs are used in many popular smartphones and tablets. It's fast-charging standard, Quick Charge, has been through multiple iterations.

The current implementation is Quick Charge 4.0, which is backward-compatible with older Quick Charge accessories and devices. Unlike USB PD, Quick Charge 2.0 and 3.0 can be delivered using the USB-A connector. Quick Charge 4.0 is exclusive to USB-C.

Quick Charge 4.0 is only present in phones that use the Qualcomm Snapdragon 8xx, and it's present in many North American tier 1 OEM Android devices made by Samsung, LG, Motorola, OnePlus, ZTE, and Google.

The Xiaomi, ZTE Nubia and the Sony Xperia devices also use QC 4.0, but they aren't sold in the US market. Huawei's phones utilize Kirin 970/980/990 chips, which use its own Supercharge standard, but they are backward-compatible with the 18W USB PD standard. Similarly, Oppo's phones have SuperVOOC, and OnePlus uses Warp Charge, and issue its compatible charger accessories if you want to take advantage of higher wattage (30W/40W/100W) charge rates.

Like USB PD, QC 3.0 and QC 4.0 are variable voltage technologies and will intelligently ramp up your device for optimal charging speeds and safety. However, Quick Charge 3.0 and 4.0 differ from USB PD in that it has some additional features for thermal management and voltage stepping with the current-generation Qualcomm Snapdragon SoCs to optimize for reduced heat footprint while charging.

It also uses a different variable voltage selection and negotiation protocol than USB PD, which Qualcomm advertises as better/safer for its own SoCs.

And for devices that use Qualcomm's current chipsets, Quick Charge 4.0 is about 25% faster than Quick Charge 3.0. The company advertises five hours of usage time on the device for five minutes of charge time.

However, while it is present in (some of) the USB C dual PD fast charger that ship with the devices themselves, and a few third-party solutions, Quick Charge 4 is not in any battery products yet. It is not just competing with USB Power Delivery; it is also compatible with USB Power Delivery.

Qualcomm's technology and ICs have to be licensed at considerable additional expense to the OEMs, whereas USB PD is an open standard.

If you compound this with Google recommending OEMs conform to USB PD over Quick Charge for Android-based products, it sounds like USB PD is the way to go, right?

Well, sort of. If you have a Quick Charge 3.0 device, definitely get a Quick Charge 3.0 battery. But if you have a Quick Charge 4.0 device or an iOS device, get at USB PD battery for now.

Which battery should you buy?
Now that you understand the fundamental charging technologies, which battery should you buy? When the first version of this article released in 2018, the product selection on the market was much more limited -- there are now dozens of vendors currently manufacturing USB PD products.
USB-C connectors have been designed hand-in-hand with USB-C Power Delivery, to handle these new high levels of power. USB-C circuit boards are specially designed to carry this increased wattage without being damaged or overheating, for enhanced safety to users and their devices.

Older connectors, such as USB-A, were first introduced in 1996, when much less power was needed than that required by today’s smartphones and tablets. This older technology is less suited to handle this increased wattage and may not have the ability to monitor heat and circuitry abnormalities.

Whether it’s a small phone or a large laptop, the USB C PD fast charger detects the connected device to deliver the right amount of power to charge that device as fast as possible. This ensures fast charging without delivering too much power which could damage circuitry.

Flick a switch and get instant power—how our ancestors would have loved electric motors! You can find them in everything from electric trains to remote-controlled cars—and you might be surprised how common they are. How many electric motors are there in the room with you right now? There are probably two in your computer for starters, one spinning your hard drive around and another one powering the cooling fan. If you're sitting in a bedroom, you'll find motors in hair dryers and many toys; in the bathroom, they're in extractor fans, and electric shavers; in the kitchen, motors are in just about every appliance from clothes washing machines and dishwashers to coffee grinders, microwaves, and electric can openers. Electric motors have proved themselves to be among the greatest inventions of all time. Let's pull some apart and find out how they work!

The basic idea of an electric motor is really simple: you put electricity into it at one end and an axle (metal rod) rotates at the other end giving you the power to drive a machine of some kind. How does this work in practice? Exactly how do your convert electricity into movement? To find the answer to that, we have to go back in time almost 200 years.

Suppose you take a length of ordinary wire, make it into a big loop, and lay it between the poles of a powerful, permanent horseshoe magnet. Now if you connect the two ends of the wire to a battery, the wire will jump up briefly. It's amazing when you see this for the first time. It's just like magic! But there's a perfectly scientific explanation. When an electric current starts to creep along a wire, it creates a magnetic field all around it. If you place the wire near a permanent magnet, this temporary magnetic field interacts with the permanent magnet's field. You'll know that two magnets placed near one another either attract or repel. In the same way, the temporary magnetism around the wire attracts or repels the permanent magnetism from the magnet, and that's what causes the wire to jump.

The link between electricity, magnetism, and movement was originally discovered in 1820 by French physicist André-Marie Ampère (1775–1867) and it's the basic science behind a Ac motor. But if we want to turn this amazing scientific discovery into a more practical bit of technology to power our electric mowers and toothbrushes, we've got to take it a little bit further. The inventors who did that were Englishmen Michael Faraday (1791–1867) and William Sturgeon (1783–1850) and American Joseph Henry (1797–1878). Here's how they arrived at their brilliant invention.

Suppose we bend our wire into a squarish, U-shaped loop so there are effectively two parallel wires running through the magnetic field. One of them takes the electric current away from us through the wire and the other one brings the current back again. Because the current flows in opposite directions in the wires, Fleming's Left-Hand Rule tells us the two wires will move in opposite directions. In other words, when we switch on the electricity, one of the wires will move upward and the other will move downward.

If the coil of wire could carry on moving like this, it would rotate continuously—and we'd be well on the way to making an electric motor. But that can't happen with our present setup: the wires will quickly tangle up. Not only that, but if the coil could rotate far enough, something else would happen. Once the coil reached the vertical position, it would flip over, so the electric current would be flowing through it the opposite way. Now the forces on each side of the coil would reverse. Instead of rotating continuously in the same direction, it would move back in the direction it had just come! Imagine an electric train with a motor like this: it would keep shuffling back and forward on the spot without ever actually going anywhere.

How an asynchronous motor works—in practice
There are two ways to overcome this problem. One is to use a kind of electric current that periodically reverses direction, which is known as an alternating current (AC). In the kind of small, battery-powered motors we use around the home, a better solution is to add a component called a commutator to the ends of the coil. (Don't worry about the meaningless technical name: this slightly old-fashioned word "commutation" is a bit like the word "commute". It simply means to change back and forth in the same way that commute means to travel back and forth.) In its simplest form, the commutator is a metal ring divided into two separate halves and its job is to reverse the electric current in the coil each time the coil rotates through half a turn. One end of the coil is attached to each half of the commutator. The electric current from the battery connects to the motor's electric terminals. These feed electric power into the commutator through a pair of loose connectors called brushes, made either from pieces of  graphite (soft carbon similar to pencil "lead") or thin lengths of springy metal, which (as the name suggests) "brush" against the commutator. With the commutator in place, when electricity flows through the circuit, the coil will rotate continually in the same direction.

A simple, experimental motor such as this isn't capable of making much power. We can increase the turning force (or torque) that the motor can create in three ways: either we can have a more powerful permanent magnet, or we can increase the electric current flowing through the wire, or we can make the coil so it has many "turns" (loops) of very thin wire instead of one "turn" of thick wire. In practice, a motor also has the permanent magnet curved in a circular shape so it almost touches the coil of wire that rotates inside it. The closer together the magnet and the coil, the greater the force the motor can produce.

Although we've described a number of different parts, you can think of a motor as having just two essential components:

There's a permanent magnet (or magnets) around the edge of the motor case that remains static, so it's called the stator of a motor.
Inside the stator, there's the coil, mounted on an axle that spins around at high speed—and this is called the rotor. The rotor also includes the commutator.
Universal motors
DC motors like this are great for battery-powered toys (things like model trains, radio-controlled cars, or electric shavers), but you don't find them in many household appliances. Small appliances (things like coffee grinders or electric food blenders) tend to use what are called universal motors, which can be powered by either AC or DC. Unlike a simple DC motor, a universal motor has an electromagnet, instead of a permanent magnet, and it takes its power from the DC or AC power you feed in:

When you feed in DC, the electromagnet works like a conventional permanent magnet and produces a magnetic field that's always pointing in the same direction. The commutator reverses the coil current every time the coil flips over, just like in a simple DC motor, so the coil always spins in the same direction.
When you feed in AC, however, the current flowing through the electromagnet and the current flowing through the coil both reverse, exactly in step, so the force on the coil is always in the same direction and the motor always spins either clockwise or counter-clockwise. What about the commutator? The frequency of the current changes much faster than the motor rotates and, because the field and the current are always in step, it doesn't actually matter what position the commutator is in at any given moment.

In simple DC and universal motors, the rotor spins inside the stator. The rotor is a coil connected to the electric power supply and the stator is a permanent magnet or electromagnet. Large AC motors (used in things like factory machines) work in a slightly different way: they pass alternating current through opposing pairs of magnets to create a rotating magnetic field, which "induces" (creates) a magnetic field in the motor's rotor, causing it to spin around. You can read more about this in our article on AC induction motors. If you take one of these induction motors and "unwrap" it, so the stator is effectively laid out into a long continuous track, the rotor can roll along it in a straight line. This ingenious design is known as a linear motor, and you'll find it in such things as factory machines and floating "maglev" (magnetic levitation) railroads.

Another interesting design is the brushless DC (BLDC) motor. The stator and rotor effectively swap over, with multiple iron coils static at the center and the permanent magnet rotating around them, and the commutator and brushes are replaced by an electronic circuit. You can read more in our main article on hub motors. Stepper motors, which turn around through precisely controlled angles, are a variation of brushless DC motors.

By understanding how a motor works you can learn a lot about magnets, electromagnets and electricity in general. In this article, you will learn what makes electric motors tick.

An electric motor for concrete mixers is all about magnets and magnetism: A motor uses magnets to create motion. If you have ever played with magnets you know about the fundamental law of all magnets: Opposites attract and likes repel. So if you have two bar magnets with their ends marked "north" and "south," then the north end of one magnet will attract the south end of the other. On the other hand, the north end of one magnet will repel the north end of the other (and similarly, south will repel south). Inside an electric motor, these attracting and repelling forces create rotational motion. ­

In the above diagram, you can see two magnets in the motor: The armature (or rotor) is an electromagnet, while the field magnet is a permanent magnet (the field magnet could be an electromagnet as well, but in most small motors it isn't in order to save power).

The motor being dissected here is a simple 10 Hp electric motor that you would typically find in a toy.

You can see that this is a small motor, about as big around as a dime. From the outside you can see the steel can that forms the body of the motor, an axle, a nylon end cap and two battery leads. If you hook the battery leads of the motor up to a flashlight battery, the axle will spin. If you reverse the leads, it will spin in the opposite direction. Here are two other views of the same motor. (Note the two slots in the side of the steel can in the second shot -- their purpose will become more evident in a moment.)

The nylon end cap is held in place by two tabs that are part of the steel can. By bendin­g the tabs back, you can free the end cap and remove it. Inside the end cap are the motor's brushes. These brushes transfer power from the battery to the commutator as the motor spins:

The axle holds the armature and the commutator. The armature is a set of electromagnets, in this case three. The armature in this motor is a set of thin metal plates stacked together, with thin copper wire coiled around each of the three poles of the armature. The two ends of each wire (one wire for each pole) are soldered onto a terminal, and then each of the three terminals is wired to one plate of the commutator.

The final piece of any DC electric motor is the field magnet. The field magnet in this motor is formed by the can itself plus two curved permanent magnets.

One end of each magnet rests against a slot cut into the can, and then the retaining clip presses against the other ends of both magnets.

To understand how an electric motor works, the key is to understand how the electromagnet works. (See How Electromagnets Work for complete details.)

An electromagnet is the basis of an electric motor. You can understand how things work in the motor by imagining the following scenario. Say that you created a simple electromagnet by wrapping 100 loops of wire around a nail and connecting it to a battery. The nail would become a magnet and have a north and south pole while the battery is connected.

Now say that you take your nail electromagnet, run an axle through the middle of it and suspend it in the middle of a horseshoe magnet as shown in the figure below. If you were to attach a battery to the electromagnet so that the north end of the nail appeared as shown, the basic law of magnetism tells you what would happen: The north end of the electromagnet would be repelled from the north end of the horseshoe magnet and attracted to the south end of the horseshoe magnet. The south end of the electromagnet would be repelled in a similar way. The nail would move about half a turn and then stop in the position shown.

You can see that this half-turn of motion is simply due to the way magnets naturally attract and repel one another. The key to an electric motor is to then go one step further so that, at the moment that this half-turn of motion completes, the field of the electromagnet flips. The flip causes the electromagnet to complete another half-turn of motion. You flip the magnetic field just by changing the direction of the electrons flowing in the wire (you do that by flipping the battery over). If the field of the electromagnet were flipped at precisely the right moment at the end of each half-turn of motion, the electric motor would spin freely.

The best gaming chair is the perfect finishing touch to a modern PC gaming setup. It really will bring your whole desktop together and make it look supremely suave. Yet these gaming thrones are good for more than style points, the top gaming chairs will also give your weary back an ample place to rest. This also explains why they can be so costly—keeping you in one piece isn't a cheap endeavour. If you've spent thousands of dollars on an extreme gaming PC build, it's only fair to give your gaming chair just as much attention. 

If you're simply looking for everyday comfort, the best gaming seats may seem over the top. With wannabe-racer bucket seats, and gaming chairs covered in satanic runes running rampant, we've made sure to include a few sleek office-style chairs in here too. Whichever route you go down, keep your posture in mind. Posture may be the last thing you think about when embarking on a ten-hour raid, but we implore you: Don't disregard ergonomics.

We've tested tens of ergonomic gaming chair from today's most well-known companies to find luxurious and affordable places to park your rear. Check those out below. And if the chairs are a bit rich for your butt, then our cheap gaming chair roundup may be more up your street.

The Secretlab Titan Evo 2022 is everything we've been looking for in a gaming chair. That's why it's rightfully taken the top spot in our best gaming chair guide from the previous incumbent, the Secretlab Titan. It was an easy decision to make, though. The Secretlab Titan Evo 2022 does everything the Titan, and Omega below, can, except better.

User-friendly ergonomics make the Titan Evo 2022 a great fit for long nights gaming or eight hours tapping away for work, and that comes down to its superb built-in back support. It's highly adjustable, which means you can nail down a great fit with ease. There's also something to be said for the 4D armrests, comfortable seat rest, and magnetic head cushion.

You read that right, a magnetic head cushion. A simple solution to fiddly straps, the Titan Evo 2022 does away with all that with a couple of powerful magnets.

Secretlab also reckons its new Neo Hybrid Leatherette material is more durable than ever, though there's still the option for the Softweave fabric we've raved about in the past.

The chair is available in three sizes: S, R, and XL.

As a complete package, then, the Secretlab Titan Evo 2022 is the archetype of a great gaming chair. It is a little pricier than its predecessors, but we think it's worth the price tag. And anyways, that higher price tag is why we still recommend the Omega below for a cheaper option while stock lasts.
The Secretlab Omega is one of the most finely constructed chairs we've tested, and although it has largely been replaced by the Titan Evo 2022 above nowadays, the higher price tag of that chair might see the Omega remain a popular option for those looking to save a little cash.

From the casters to the base, the lift mechanism, armrests, and seat back, Secretlab has used some of the best materials available. The Omega was upgraded with Secretlab's 2020 series of improvements, which includes premium metal in the armrest mechanism, making it silky smooth to adjust and even more durable, and adding the company's ridiculously durable PU Leather 2.0. 

The chair features a high-quality, cold-cured foam to provide support. It feels a little firm at first but gets more comfortable after extended use. The Omega stands out from the crowd with its velour memory foam lumbar and head pillows. These are so comfortable that we could smoothly fully recline the chair and take a nap if we wanted to. Though that's not a great look in the office... If you're looking to treat your body with a chair that will genuinely last, the Secretlab Omega is worth every penny.
Perhaps you've heard of the Herman Miller Embody. It occupied a top position in our best office chair roundup for a long time, but that has come to an end. Not for lack of comfort or acclaim, simply because the famed chair manufacturer has partnered up with Logitech to create something tailor-made to our gaming rumps.

Admittedly, the Logitech G x Herman Miller Embody doesn't differ much from its commercial cousin. That's hardly a mark against it, however. The Embody's cascading back support design and absurdly high quality make a welcome return but now comes with a few more flourishes to win over gamers. Specifically, extra cooling material designed to support a more active gaming position.

It's not so much the changes that make the Embody stand out as one of the best gaming chair with footrest going. It's what's been kept the same. The tried and tested Embody design is simply one of the best chairs for office work or gaming. It's incredibly comfortable over prolonged use, supports an active and healthy posture, and is easily fitted to your frame.

The warranty, too, is a standout feature. At 12 years, including labor, and rated to 24-hour use over that time, it's a chair that is guaranteed to last you over a decade, if not longer. So while the initial price tag may seem steep, and that it is, the reality is you're certain to get your money's worth in the long run. And your back will be thankful for it, too.
If you're the sort of person who prioritizes functionality over flash, the NeueChair is an excellent option. This isn't to say it's not stylish—quite the opposite; the NeueChair comes in a sleek, muted obsidian or flashy chrome/silver, both with bold, sweet curved supports on the back and an attractive black mesh. But, more importantly, the NeueChair is built to last, with a heavy, sturdy industrial construction. Even the chair's weight in the packaging indicates a solid piece of carefully constructed industrial art: it's heavy and substantial. 

Assembling it is a breeze, as it comes in two discrete pieces and is simply a matter of inserting the casters and then pushing the two parts together. Almost every aspect of the seat is adjustable, from the armrests to the lumbar support system that lets you change the height depth of the backrest. It's one of the best office chairs I've ever had the pleasure to sit in, and if you can afford the admittedly steep price tag, well worth the investment.
If you're a big and tall gamer, you might have noticed that there aren't many racing gaming chair that can support your unique build. Whether it's a lower weight capacity or too short, or even feels like it'll break as soon as you sit in it, finding a chair for you might seem nearly impossible.

The AndaSeat Kaiser 2 screams large and in charge, supporting gamers up to 397lbs and 7ft tall. The Kaiser 2 is built on a solid steel frame with oversized bars to provide support. 

Covered in premium PVC leather and extra thick memory foam cushioning, the Kaiser 2 manages to look more like a gaming chair for grownups. Available in black and a lovely maroon, no more will have to stuff yourself into a tiny gaming chair hope for the best. The Kaiser 2 manages to do both the function, comfort, and style you want in your premium gaming chair. 
When buying a gaming chair, it's easy to forget your health. After all, most are advertised as luxurious, cushioned thrones that soothe your every ache as you smash the crap out of your foes in Apex Legends. But that isn't true, and for some, it's important to pick a chair that takes back support seriously. With some of the team have used it daily for almost a year, we can thoroughly recommend the Noblechairs Hero in uPVC leather. While not the most exciting of chairs, or the sportiest, it certainly does a good job of taking care of your back.

The Hero is easy to assemble, except for the bit where you attach the back to the seat, so make sure you have a buddy for that. It's firm and supportive, and extremely sturdy. As a word of warning: it is substantial, so if you prefer a softer chair that isn't as good for your lumbar, this maybe isn't for you. 

Aside from that, it has a decent recline, can withstand frames of up to 330 lbs, and has fully adjustable wrist-rests. It's heavy but glides pretty easily on the supplied casters. It'll look just fine in both an office or gaming setup, so you're getting a chair that can do both. Not bad, if you can afford it.
Corsair's latest addition to its lineup of premium reclining gaming chair, the T3 Rush, has gotten a much-needed facelift. The T3 Rush is an insanely comfy chair thanks to its memory foam lumbar pillow but, more importantly, uses a breathable soft fabric in place of faux leather. The benefit of this is that it retains less heat, keeping you fresh and comfy instead of sweating in your squeaky pleather.

The Rush also reclines to a ridiculous 180 degrees in case you wanted to lie back and take a comfy cat nap before you take on another marathon streaming session of Apex Legends or CS: GO.

The only major downside for the T3 Rush mostly fits for smaller framed users. If you require a little larger seat, the T3 will be an uncomfortably tight fit. Other than that, the T3 Rush is an impressive-looking gaming chair that doesn't need a loud color to make a statement.
The DXRacer Master is a chair for people with money to spend, but it justifies the price by being an extremely luxuriant and comfortable chair. What's more, the DXRacer Master can be customized with modular parts (sold at an added cost) like mesh seat and backrests, leg rests, and even a rotating arm that bolts onto the base and can hold anything from a laptop to your phone.

Choosing not to invest in these extra parts won't compromise the chair itself, though, because DXRacer went all out on its features. Built-in lumbar support and an adjustable, rail-mounted headrest are great features, along with four-dimensional armrests. The microfiber leather is especially nice, and much of the chair is made of metal, which makes it feel sturdy.

It's clear that the DXRacer Master was built to last, and its understated look is great if you're not into the flashy designs seen on most other gaming chairs. But, boy, it will cost you for all this luxury: The DXRacer Master is still $80 more than the Secret Lab Omega, our favorite chair. But it's worth considering if you want to go all out and get something with all the bells and whistles.

A gear pump is a type of positive displacement (PD) pump. Gear pumps use the actions of rotating cogs or gears to transfer fluids.  The rotating gears develop a liquid seal with the pump casing and create a vacuum at the pump inlet.  Fluid, drawn into the pump, is enclosed within the cavities of the rotating gears and transferred to the discharge.  A gear pump delivers a smooth pulse-free flow proportional to the rotational speed of its gears.

There are two basic designs of gear pump: internal and external (Figure 1).  An internal gear pump has two interlocking gears of different sizes with one rotating inside the other.  An external gear pump consists of two identical, interlocking gears supported by separate shafts.  Generally, one gear is driven by a motor and this drives the other gear (the idler).  In some cases, both shafts may be driven by motors.  The shafts are supported by bearings on each side of the casing.

This article describes plastic gear pump in more detail.
There are three stages in an internal gear pump’s working cycle: filling, transfer and delivery (Figure 2).

As the gears come out of mesh on the inlet side of the pump, they create an expanded volume.  Liquid flows into the cavities and is trapped by the gear teeth as the gears continue to rotate against the pump casing.

The trapped fluid is moved from the inlet, to the discharge, around the casing.

As the teeth of the gears become interlocked on the discharge side of the pump, the volume is reduced and the fluid is forced out under pressure.

No fluid is transferred back through the centre, between the gears, because they are interlocked.  Close tolerances between the gears and the casing allow the pump to develop suction at the inlet and prevent fluid from leaking back from the discharge side (although leakage is more likely with low viscosity liquids).

External gear pump designs can utilise spur, helical or herringbone gears (Figure 3).  A helical gear design can reduce pump noise and vibration because the teeth engage and disengage gradually throughout the rotation.  However, it is important to balance axial forces resulting from the helical gear teeth and this can be achieved by mounting two sets of ‘mirrored’ helical gears together or by using a v-shaped, herringbone pattern.  With this design, the axial forces produced by each half of the gear cancel out.  Spur gears have the advantage that they can be run at very high speed and are easier to manufacture.

Gear pumps are compact and simple with a limited number of moving parts. They are unable to match the pressure generated by reciprocating pumps or the flow rates of centrifugal pumps but offer higher pressures and throughputs than vane or lobe pumps. External gear pumps are particularly suited for pumping water, polymers, fuels and chemical additives. Small external gear pumps usually operate at up to 3500 rpm and larger models, with helical or herringbone gears, can operate at speeds up to 700 rpm. External gear pumps have close tolerances and shaft support on both sides of the gears. This allows them to run at up to 7250 psi (500 bar), making them well suited for use in hydraulic power applications.

Since output is directly proportional to speed and is a smooth pulse-free flow, external gear pumps are commonly used for metering and blending operations as the metering is continuous and the output is easy to monitor. The low internal volume provides for a reliable measure of liquid passing through a pump and hence accurate flow control. They are also used extensively in engines and gearboxes to circulate lubrication oil. External gear pumps can also be used in hydraulic power applications, typically in vehicles, lifting machinery and mobile plant equipment. Driving a gear pump in reverse, using oil pumped from elsewhere in a system (normally by a tandem pump in the engine), creates a motor. This is particularly useful to provide power in areas where electrical equipment is bulky, costly or inconvenient. Tractors, for example, rely on engine-driven external gear pumps to power their services.

External gear pumps can be engineered to handle aggressive liquids. While they are commonly made from cast iron or stainless steel, new alloys and composites allow the pumps to handle corrosive liquids such as sulphuric acid, sodium hypochlorite, ferric chloride and sodium hydroxide.

What are the limitations of a gear pump?
External gear pumps are self-priming and can dry-lift although their priming characteristics improve if the gears are wetted.  The gears need to be lubricated by the pumped fluid and should not be run dry for prolonged periods.  Some gear pump designs can be run in either direction so the same pump can be used to load and unload a vessel, for example.

The close tolerances between the gears and casing mean that these types of pump are susceptible to wear particularly when used with abrasive fluids or feeds containing entrained solids. External gear pumps have four bearings in the pumped medium, and tight tolerances, so are less suited to handling abrasive fluids.  For these applications, universal gear pump are more robust having only one bearing (sometimes two) running in the fluid.  A gear pump should always have a strainer installed on the suction side to protect it from large, potentially damaging, solids.

Generally, if the pump is expected to handle abrasive solids it is advisable to select a pump with a higher capacity so it can be operated at lower speeds to reduce wear.  However, it should be borne in mind that the volumetric efficiency of a gear pump is reduced at lower speeds and flow rates.  A gear pump should not be operated too far from its recommended speed.

For high temperature applications, it is important to ensure that the operating temperature range is compatible with the pump specification.  Thermal expansion of the casing and gears reduces clearances within a pump and this can also lead to increased wear, and in extreme cases, pump failure.

Despite the best precautions, gear pumps generally succumb to wear of the gears, casing and bearings over time.  As clearances increase, there is a gradual reduction in efficiency and increase in flow slip: leakage of the pumped fluid from the discharge back to the suction side.  Flow slip is proportional to the cube of the clearances between the cog teeth and casing so, in practice, wear has a small effect until a critical point is reached, from which performance degrades rapidly.

Gear pumps continue to pump against a back pressure and, if subjected to a downstream blockage will continue to pressurise the system until the pump, pipework or other equipment fails.  Although most gear pumps are equipped with relief valves for this reason, it is always advisable to fit relief valves elsewhere in the system to protect downstream equipment.

The high speeds and tight clearances of external gear pumps make them unsuitable for shear-sensitive liquids such as foodstuffs, paint and soaps.  Internal gear pumps, operating at lower speed, are generally preferred for these applications.

What are the main applications for gear pumps?
External gear pumps are commonly used for pumping water, light oils, chemical additives, resins or solvents.  They are preferred in any application where accurate dosing is required such as fuels, polymers or chemical additives.  The output of a gear pump is not greatly affected by pressure so they also tend to be preferred in any situation where the supply is irregular.


Summary
An external gear pump moves a fluid by repeatedly enclosing a fixed volume within interlocking gears, transferring it mechanically to deliver a smooth pulse-free flow proportional to the rotational speed of its gears.

External gear pumps are commonly used for pumping water, light oils, chemical additives, resins or solvents.  They are preferred in applications where accurate dosing or high pressure output is required.  External gear pumps are capable of sustaining high pressures.  The tight tolerances, multiple bearings and high speed operation make them less suited to high viscosity fluids or any abrasive medium or feed with entrained solids.
External-gear pumps are rotary, positive displacement machines capable of handling thin and thick fluids in both pumping and metering applications. Distinct from internal-gear pumps which use “gear-within-a-gear” principles, external-gear pumps use pairs of gears mounted on individual shafts. They are described here along with a discussion of their operation and common applications. For information on other pumps, please see our Pumps Buyers Guide.

Spur gear pumps
Spur gear pumps use pairs of counter-rotating toothed cylinders to move fluid between low-pressure intakes and high-pressure outlets. Fluid is trapped in pockets formed between gear teeth and the pump body until the rotating gear pairs bring individual elements back into mesh. The decreasing volume of the meshing gears forces the fluid out through the discharge port. A relatively large number of teeth minimizes leakage as the gear teeth sweep past the pump casing.

Spur gear pumps can be noisy due to a certain amount of fluid becoming trapped in the clearances between meshing teeth. Sometimes discharge pockets are added to counteract this tendency.

Spur gear pumps are often fitted with sleeve bearings or bushings which are lubricated by the fluid itself—usually oil. Other fluids that lack oil’s lubricity generally demand more stringent pump designs, including locating bearings outside of the wetted cavities and providing appropriate seals. Dry-running bearings are sometimes used. The use of simply-supported shafts (as opposed to cantilevered arrangements seen in many internal gear designs) makes for a robust pump assembly capable of handling very thick liquids, such as tar, without concern for shaft deflection.

Helical gear pumps
Similar to the spur gear pump, the helical gear pump uses a pair of single- or double-helical (herringbone) gears. Helical gears run quieter than spur gears but develop thrust loads which herringbone gears are intended to counteract. These designs are often used to move larger volumes than spur gear pumps. Helical gears produce fewer pulsations than stainless gear pump as the meshing of teeth is more gradual compared with spur-gear designs. Helix angles run between 15 and 30°.

Both the helical and herringbone gear pumps eliminate the problem of trapping fluid in the mesh. These designs can introduce leakage losses where the teeth mesh, however, unless very tight tooth clearances are maintained. The higher manufacturing costs associated with herringbone gear pumps must be balanced against their improved performance.

Applications
External-gear pumps can pump fluids of nearly any viscosity, but speed must normally be reduced for thicker materials. A typical helical gear pump might run at 1500 rpm to move a relatively thin fluid such as varnish but would have to drop its speed nearer to 500 rpm to pump material as thick as molasses in July.

External-gear pumps generally are unsuited for materials containing solids as these can lead to premature wear, although some manufacturers make pumps specifically for this purpose, usually through the use of hardened steel gears or gears coated with elastomer. External-gear pumps are self-priming and useful in low NPSH applications. They generally deliver a smooth, continuous flow. In theory, at least, they are bi-directional. They are available as tandem designs for supplying separate or combined fluid-power systems.

These pumps are capable of handling very hot fluids although the clearances must be closely matched to the expected temperatures to insure proper operation. Jacketed designs are available as well.

External-gear pumps see wide applications across many industries: food manufacturers use them to move thick pastes and syrups, in filter presses, etc.; petrochemical industries deploy them in high-pressure metering applications; engine makers use them for oil delivery. They are used as transfer pumps. Special designs are available for aerospace applications. Pumps for fluid power will conform to SAE bolt-hole requirements.

External-gear pumps are manufactured from a variety of materials including bronze, lead-free alloys, stainless steel, cast and ductile iron, Hastelloy, as well as from a number of non-metals.

External-gear pumps can be manufactured as sanitary designs for food, beverage, and pharmaceutical service. The gears can be overhung, supported by bearings outside the housing with a variety of seals and packings available. Access to these internal pump components through a cover plate makes sanitizing straightforward. Gears are commonly manufactured from composites of PTFE and stainless steel as well as other plastics. Close-coupled and sealless designs are available.

External gear pumps are the least costly of the various positive-displacement pumps but also the least efficient. Pressure imbalances between suction and discharge sides can promote early bearing wear, giving them somewhat short life expectancies.

One general disadvantage that all heat preservation gear pump share over some other positive-displacement pump styles – vane pumps, for instance – is their inability to provide a variable flow rate at a given input speed. Where this is a requirement, a work-around is to use drives capable of speed control, though this is not always a practical solution.

Finally, while rotary, positive-displacement pumps are capable of pumping water, their primary application is in oils and viscous liquids because of the need to keep rubbing surfaces lubricated and the difficulty in sealing very thin fluids. For most applications where water is the media, the centrifugal, or dynamic-displacement pump, has been the clearer choice.

This review highlights recent progress in the synthesis and application of vinyl ethers (VEs) as monomers for modern homo- and co-polymerization processes. VEs can be easily prepared using a number of traditional synthetic protocols including a more sustainable and straightforward manner by reacting gaseous acetylene or calcium carbide with alcohols. The remarkably tunable chemistry of VEs allows designing and obtaining polymers with well-defined structures and controllable properties. Both VE homopolymerization and copolymerization systems are considered, and specific emphasis is given to the novel initiating systems and to the methods of stereocontrol.

The composition of chlorophyll-precursor pigments, particularly the contents of diethylene glycol divinyl ether, in etiolated tissues of higher plants were determined by polyethylene-column HPLC (Y. Shioi, S. I. Beale [1987] Anal Biochem 162: 493-499), which enables the complete separation of these pigments. DV-Pchlide was ubiquitous in etiolated tissue of higher plants. From the analyses of 24 plant species belonging to 17 different families, it was shown that the concentration of DV-Pchlide was strongly dependent on the plant species and the age of the plants. The ratio of DV-Pchlide to MV-Pchlide in high DV-Pchlide plants such as cucumber and leaf mustard decreased sharply with increasing age. Levels of DV-Pchlide in Gramineae plants were considerably lower at all ages compared with those of other plants. Etiolated tissues of higher plants such as barley and corn were, therefore, good sources of MV-Pchlide. Absorption spectra of the purified MV- and DV-Pchlides in ether are presented and compared.

Both epoxides and vinyl ethers can be polymerized cationically albeit through different intermediates. However, in the case of epoxide-vinyl ether mixtures the exact mechanism of cationically initiated polymerization is unclear. Thus, although vinyl ethers can be used as reactive diluents for epoxides it is uncertain how they would affect their reactivity. Cationic photocuring of diepoxides has many industrial applications. Better understanding of the photopolymerization of epoxy-vinyl ether mixtures can lead to new applications of cationically photocured systems. In this work, photo-DSC and real-time Fourier Transform Infrared Spectroscopy (RT-FTIR) were used to study cationic photopolymerization of diepoxides and vinyl ethers. In the case of mixtures of aromatic epoxides with tri(ethylene glycol) divinyl ether, TEGDVE, photo-DSC measurements revealed a greatly reduced reactivity in comparison to the homopolymerizations and suggested the lack of copolymerization between aromatic epoxides and TEGDVE. On the other hand, for mixtures of 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate, ECH, with TEGDVE the results indicated high reactivity of the blends. The polymerization mechanism might include copolymerization. To examine this mechanism, mixtures of the ECH with a tri(ethylene glycol) mono-vinyl ether, TEGMVE, were studied by both photo-DSC and RT-FTIR. Principal component analysis (PCA) proved to be an efficient tool in analyzing a large matrix of the spectral data from the polymerization system. PCA was able to provide insight into the reasons for the differences among replicated experiments with the same composition ratio and supported the hypothesis of copolymerization in the ECH/TEGMVE system. Thus, blends of cycloaliphatic epoxides and vinyl ethers seem to have a great potential for applications in high-productivity industrial photopolymerization processes.

Vinyl acetate is an organic compound with the formula CH3CO2CH=CH2. This colorless liquid is the precursor to polyvinyl acetate, an important industrial polymer.[3]
The worldwide production capacity of 1,4-bis(vinyloxy)-butane was estimated at 6,969,000 tonnes/year in 2007, with most capacity concentrated in the United States (1,585,000 all in Texas), China (1,261,000), Japan (725,000) and Taiwan (650,000).[4] The average list price for 2008 was $1600/tonne. Celanese is the largest producer (ca 25% of the worldwide capacity), while other significant producers include China Petrochemical Corporation (7%), Chang Chun Group (6%), and LyondellBasell (5%).[4]

It is a key ingredient in furniture glue.[5]
It can be polymerized to give polyvinyl acetate (PVA). With other monomers it can be used to prepare various copolymers such as ethylene-vinyl acetate (EVA), vinyl acetate-acrylic acid (VA/AA), polyvinyl chloride acetate (PVCA), and polyvinylpyrrolidone (Vp/Va copolymer, used in hair gels).[8] Due to the instability of the radical, attempts to control the polymerization by most "living/controlled" radical processes have proved problematic. However, RAFT (or more specifically, MADIX) polymerization offers a convenient method of controlling the synthesis of PVA by the addition of a xanthate or a dithiocarbamate chain transfer agent.
Vinyl acetate undergoes many of the reactions anticipated for an alkene and an ester. Bromine adds to give the dibromide. Hydrogen halides add to give 1-haloethyl acetates, which cannot be generated by other methods because of the non-availability of the corresponding halo-alcohols. Acetic acid adds in the presence of palladium catalysts to give ethylidene diacetate, CH3CH(OAc)2. It undergoes transesterification with a variety of carboxylic acids.[9] The alkene also undergoes Diels–Alder and 2+2 cycloadditions.

Tests suggest that vinyl acetate is of low toxicity. Oral LD50 for rats is 2920 mg/kg.[3]

On January 31, 2009, the Government of Canada's final assessment concluded that exposure to vinyl acetate is not harmful to human health.[12] This decision under the Canadian Environmental Protection Act (CEPA) was based on new information received during the public comment period, as well as more recent information from the risk assessment conducted by the European Union.

In the context of large-scale release into the environment, it is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U.S. Emergency Planning and Community Right-to-Know Act (42 U.S.C. 11002), under which it "does not meet toxicity criteria[,] but because of its acute lethality, high production volume [or] known risk is considered a chemical of concern". By this law, it is subject to strict reporting requirements by facilities that produce, store, or use it in quantities greater than 1000 pounds.[13]


To date, methods of quantum-chemical calculations have been increasingly developed. As a result, it is possible to estimate the geometry of molecules, calculate the stability of intermediate products and transition states. In the experimental method of calculating such results for most reactions, along with a multi-stage process, there are difficulties associated with the appearance of intermediate stages and the presence of intermediate reaction products in an extremely small time.

Radical copolymerization of polyethylene glycol maleate with Di(ethylene Glycol) monovinyl ether of monoethanol amine has been performed for the first time. Radical co- and terpolymerization of the systems polyethylene glycol maleate with acrylamide and 1,4-butanediol monovinyl ether of monoethanol amine has been studied. Molecular weight of polyethylene glycol maleate has been determined using light scattering and gel permeation chromatography. The compositions of the polymers and copolymerization constants of the studied systems have been determined. The composition of the copolymers has been found using gas chromatography. Kinetic curves show that with increasing molar fraction of acrylamide in the solution the reaction rate and swelling capacity of the copolymers increase. It has been shown that the composition of terpolymers determined experimentally differs considerably from the one calculated taking into account obtained constants of copolymerization. Deviations found are due to various intermolecular interactions in these systems. The possibility of controlling the properties of network copolymers of polyethylene glycol maleate by changing external factors has been studied. Swelling capacity of the copolymers investigated was studied using gravimetric method.
Hydrogels have been widely used for various biomedical and pharmaceutical applications due to their biocompatibility, high water content and rubbery nature, which resemble natural tissue. Polyethylene glycol (PEG) crosslinked poly(methyl diethylene glycol monovinyl ether and maleic acid) (PMVE/MA) hydrogel is widely studied as a vehicle for various types of drug delivery. It has been reported that swelling and diffusion property of hydrogel are important features for their effectiveness. Higher swelling of PMVE/MA hydrogel facilitates greater amount of drug to be delivered. However, delivery of high molecular weight drugs such as ovalbumin and bevacizumab is still a challenge with existing formulation of PMVE/MA hydrogels. This study aims to optimise PMVE/MA hydrogel formulations and determine the swelling kinetics of different hydrogel formulations.

Methods
PMVE/MA hydrogels were prepared by inducing esterification reaction with PEG. Each formulation of hydrogel consists of different concentration and molecular mass of PMVE/MA and PEG. Swelling kinetics of each formulation were studied by calculating % swelling and second order kinetic model was used to calculate the swelling rate constant (Ks) and degree of swelling at equilibrium (Seq). The effect of different foaming agents (Na2CO3 and NaHCO3) on the swelling of hydrogel was also studied.
   
Results 
Our results shows that hydrogels synthesised from higher molecular weight 15% (w/w) PMVE/MA and 7.5 % (w/w) PEG 12,000 have 2200% swelling. The swelling of hydrogel decreased with increasing concentrations of PMVE/MA and PEG. Hydrogel mixture containing PEG 12,000 with longer polymer chains resulted in better swelling compared to PEG 10,000. Meanwhile high concentration of foaming agents (up to 3% w/w) has a positive effect on hydrogel swelling. 

Conclusion 
The hydrogels formulation containing 15% (w/w) PMVE/MA and 7.5 % (w/w) PEG 12,000 in this study yielded 1.28 times greater swelling compared to previously reported formulation. It is proposed that, this hydrogel would serve as a better vehicle candidate for macromolecular drug delivery.

BAMIYAN, Afghanistan — Here is a reminder to someone with the initials A.B., who on March 8 climbed inside the cliff out of which Bamiyan’s two giant Buddhas were carved 1,500 years ago.

In a domed chamber — reached after a trek through a passageway that worms its way up the inside of the cliff face — A.B. inscribed initials and the date, as hundreds of others had in many scripts, then added a little heart.

It’s just one of the latest contributions to the destruction of the World Heritage Site of Bamiyan’s famous Buddhas.

The worst was the Taliban’s effort in March 2001, when the group blasted away at the wooden buddha statue, one 181 feet and the other 125 feet tall, which at the time were thought to be the two biggest standing Buddhas on the planet.

It took the Taliban weeks, using artillery and explosive charges, to reduce the Buddhas to thousands of fragments piled in heaps at the foot of the cliffs, outraging the world.

Since then, the degradation has continued, as Afghanistan and the international community have spent 18 years debating what to do to protect or restore the site, with still no final decision and often only one guard on duty.

One recent idea came from a wealthy Chinese couple, Janson Hu and Liyan Yu. They financed the creation of a Statue of Liberty-size 3D light projection of an artist’s view of what the larger Buddha, known as Solsol to locals, might have looked like in his prime.

The image was beamed into the niche one night in 2015; later the couple donated their $120,000 projector to the culture ministry.

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The local authorities bring it out on special occasions, but rarely, as Bamiyan has no city power supply, other than fields of low-capacity solar panels. The 3D-image projector is power-hungry and needs its own diesel generator.

Most of the time, the remains of the monument are so poorly guarded that anyone can buy a ticket ($4 for foreigners, 60 cents for Afghans), walk in and do pretty much whatever he wants. And many do.

Souvenir-hunters pluck pieces of painted stucco decorations from the network of chambers or take away chunks of fallen sandstone. Graffiti signatures, slogans, even solicitations for sex abound.

Anyone can, as A.B. did, crawl through the passageways surrounding the towering niches in the cliff, through winding staircases tunneled into the sandstone and up steps with risers double the height of modern ones, as if built for giants.

At the end of this journey, you arrive above the eastern niche, which housed the smaller Buddha, and stand on a ledge just behind where the statue’s head once was, taking in the splendid Buddha’s eye view of snow-capped mountains and the lush green valley far below.

The soft sandstone of the staircases crumbles underfoot, so that the very act of climbing them is at least in part a guilty pleasure — though no longer very dangerous. Twisted iron banisters set in the stone make the steep inclines and windows over the precipices more safely navigable, if not as authentically first millennium.

When the Taliban demolished the Buddhas, in an important sense they botched the job.

The Buddhas, built over perhaps a century from 550 A.D. or so, were just the most prominent parts of a complex of hundreds of caves, monasteries and shrines, many of them colorfully decorated by the thousands of monks who meditated and prayed in them.

Even without the Buddhas themselves, their niches remain, impressive in their own right; the Statue of Liberty would fit comfortably in the western one.

Unesco has declared the whole valley, including the more than half-mile-long cliff and its monasteries, a World Heritage Site.

“If the Taliban come back again to destroy it, this time they would have to do the whole cliff,” Aslam Alawi, the local head of the Afghan culture ministry, said.

Unesco has also declared the Bamiyan Buddhas complex a “World Heritage Site in Danger,” one of 54 worldwide. The larger western niche is still at risk of collapsing.

When the Taliban seized power in Afghanistan in 1996, they imposed an extremist version of Islamic law across the country. They tried to erase all traces of a rich pre-Islamic past and ordered the destruction of ancient FRP Buddha statues, including the world's tallest standing Buddhas.

Those memories are still alive for millions of Afghans. And now they have become present concerns, as the US and Afghan government negotiate with the Taliban for a deal that could see them return to power in Afghanistan.

The BBC's Shoaib Sharifi visited the National Museum in Kabul where a team are rebuilding some of the ancient Buddha sculptures that were destroyed by the Taliban.

Some of the earliest known statues depicting the Buddha have him in startling costume—draped in the lushly folded fabric of ancient Greece or Rome. Sometimes he has Greco-Roman facial features, naturalistically rendered and muscled torsos, or is even shown protected by Hercules. 

Many of these striking Buddhas hailed from Hadda, a set of monasteries in modern-day Afghanistan where Buddhism flourished for a thousand years before the rise of Islam. Located on the Silk Road, the area had frequent contact with the Mediterranean—hence the Buddha’s Hellenistic features. One of the richest collections of this unique art from Hadda was destroyed in 2001, when the Taliban ransacked the National Museum of Afghanistan and shattered the museum’s Buddha statues. 

Nearly two decades later, the museum’s conservators are working with the University of Chicago’s Oriental Institute, one of the world’s foremost research centers on the civilizations of the ancient Middle East, to bring the collection back to life. Supported by cultural heritage preservation grants from the U.S. Embassy in Kabul, OI researchers, along with Afghan colleagues, are painstakingly cleaning, sorting and reassembling statues from the more than 7,500 fragments left behind, which museum employees swept up and saved in trunks in the basement. 

“When they were broken, we lost a part of history—an important period of high artistic achievement—which these objects represent,” said Mohammad Fahim Rahimi, director of the National Museum of Afghanistan. “They are the only pieces remaining from the archaeological sites; Hadda was burned and looted during the 1980s, so these pieces at the museum are all we have left. By reviving them, we are reviving part of our history.”

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The ceramic buddha statue are beautiful, by all accounts. First excavated by French archaeologists in the 1930s, and spanning 500 years of Afghanistan’s history between the first and sixth centuries A.D., they are an example of a rare art form unique to the region, often called the Gandharan style. Some stand alone and others in tableaus, ranging from life-size to others that can fit in the palm of a hand. But the task of reconstructing them is more than a puzzle. 

The materials these ancient artisans used were primarily limestone, schist and stucco—which tend to crumble and disintegrate under duress, rather than simply crack. “It’s more like trying to assemble pieces from 30 different jigsaw puzzles that have all been dumped together—without the pictures from the boxes,” said Gil Stein, professor at the Oriental Institute and a leading expert on the rise of social complexity in the ancient Near East. 

Stein heads the project, which is part of the OI’s ongoing work with the National Museum of Afghanistan Cultural Preservation Partnership. Begun in 2012, the partnership has helped restore the museum’s infrastructure, including developing a bilingual database to document the first full inventory of the museum’s collections, as well as training conservators in the latest techniques for preserving and restoring objects. 

The collection is largely from the Hadda monasteries located in northwestern Afghanistan, near the modern-day city of Jalalabad. The region’s warm climate fosters citrus and pomegranate trees and helped it blossom as a center of trade on the Silk Road for centuries—thus its art influenced by both East and West.

‘The big puzzle’

Alejandro Gallego López, the OI’s field director in Afghanistan, explained the process of restoring the white marble buddha statue. First is to assess the collection—identifying and classifying features, such as archaeological motifs, and visible parts of bodies, like legs, heads or arms. This census can help them estimate how many objects there were originally (they think it was between 350 and 500). 

In trying to keep up with emissions and fuel efficiency laws, the fuel system used in modern cars has changed a lot over the years. The 1990 Subaru Justy was the last car sold in the United States to have a carburetor; the following model year, the Justy had fuel injection. But fuel injection has been around since the 1950s, and electronic fuel injection was used widely on European cars starting around 1980. Now, all cars sold in the United States have fuel injection systems.

In this article, we'll learn how the fuel gets into the cylinder of the engi­ne, and what terms like "multi-port fuel injection" and "throttle body fuel injection" mean.
­For most of the existence of the internal combustion engine, the carburetor has been the device that supplied fuel to the engine. On many other machines, such as lawnmowers and chainsaws, it still is. But as the automobile evolved, the carburetor got more and more complicated trying to handle all of the operating requirements. For instance, to handle some of these tasks, carburetors had five different circuits:

Main circuit - Provides just enough fuel for fuel-efficient cruising
Idle circuit - Provides just enough fuel to keep the engine idling
Accelerator pump - Provides an extra burst of fuel when the accelerator pedal is first depressed, reducing hesitation before the engine speeds up
Power enrichment circuit - Provides extra fuel when the car is going up a hill or towing a trailer
Choke - Provides extra fuel when the engine is cold so that it will start
In order to meet stricter emissions requirements, catalytic converters were introduced. Very careful control of the air-to-fuel ratio was required for the catalytic converter to be effective. Oxygen sensors monitor the amount of oxygen in the exhaust, and the engine control unit (ECU) uses this information to adjust the air-to-fuel ratio in real-time. This is called closed loop control -- it was not feasible to achieve this control with carburetors. There was a brief period of electrically controlled carburetors before fuel injection systems took over, but these electrical carbs were even more complicated than the purely mechanical ones.

At first, carburetors were replaced with throttle body FIAT fuel injector systems (also known as single point or central fuel injection systems) that incorporated electrically controlled fuel-injector valves into the throttle body. These were almost a bolt-in replacement for the carburetor, so the automakers didn't have to make any drastic changes to their engine designs.

Gradually, as new engines were designed, throttle body fuel injection was replaced by multi-port fuel injection (also known as port, multi-point or sequential fuel injection). These systems have a fuel injector for each cylinder, usually located so that they spray right at the intake valve. These systems provide more accurate fuel metering and quicker response.

When You Step on the Gas
The gas pedal in your car is connected to the throttle valve -- this is the valve that regulates how much air enters the engine. So the gas pedal is really the air pedal.

When you step on the gas pedal, the throttle valve opens up more, letting in more air. The engine control unit (ECU, the computer that controls all of the electronic components on your engine) "sees" the throttle valve open and increases the fuel rate in anticipation of more air entering the engine. It is important to increase the fuel rate as soon as the throttle valve opens; otherwise, when the gas pedal is first pressed, there may be a hesitation as some air reaches the cylinders without enough fuel in it.

Sensors monitor the mass of air entering the engine, as well as the amount of oxygen in the exhaust. The ECU uses this information to fine-tune the fuel delivery so that the air-to-fuel ratio is just right.

­In order to provide the correct amount of fuel for every operating condition, the e­ngine control unit (ECU) has to monitor a huge number of input sensors. Here are just a few:

Nox sensor - Tells the ECU the mass of air entering the engine
Oxygen sensor(s) - Monitors the amount of oxygen in the exhaust so the ECU can determine how rich or lean the fuel mixture is and make adjustments accordingly
Throttle position sensor - Monitors the throttle valve position (which determines how much air goes into the engine) so the ECU can respond quickly to changes, increasing or decreasing the fuel rate as necessary
Coolant temperature sensor - Allows the ECU to determine when the engine has reached its proper operating temperature
Voltage sensor - Monitors the system voltage in the car so the ECU can raise the idle speed if voltage is dropping (which would indicate a high electrical load)
Manifold absolute pressure sensor - Monitors the pressure of the air in the intake manifold
The amount of air being drawn into the engine is a good indication of how much power it is producing; and the more air that goes into the engine, the lower the manifold pressure, so this reading is used to gauge how much power is being produced.
Engine speed sensor - Monitors engine speed, which is one of the factors used to calculate the pulse width
There are two main types of control for multi-port systems: The fuel injectors can all open at the same time, or each one can open just before the intake valve for its cylinder opens (this is called sequential multi-port fuel injection).

The advantage of sequential vw fuel injector is that if the driver makes a sudden change, the system can respond more quickly because from the time the change is made, it only has to wait only until the next intake valve opens, instead of for the next complete revolution of the engine.

Engine Controls and Performance Chips
­­The algorithms that control the engine are quite complicated. The software has to allow the car to satisfy emissions requirements for 100,000 miles, meet EPA fuel economy requirements and protect engines against abuse. And there are dozens of other requirements to meet as well.

The engine control unit uses a formula and a large number of lookup tables to determine the pulse width for given operating conditions. The equation will be a series of many factors multiplied by each other. Many of these factors will come from lookup tables. We'll go through a simplified calculation of the fuel injector pulse width. In this example, our equation will only have three factors, whereas a real control system might have a hundred or more.

Pulse width = (Base pulse width) x (Factor A) x (Factor B)

In order to calculate the pulse width, the ECU first looks up the base pulse width in a lookup table. Base pulse width is a function of engine speed (RPM) and load (which can be calculated from manifold absolute pressure). Let's say the engine speed is 2,000 RPM and load is 4. We find the number at the intersection of 2,000 and 4, which is 8 milliseconds.

From this example, you can see how the control system makes adjustments. With parameter B as the level of oxygen in the exhaust, the lookup table for B is the point at which there is (according to engine designers) too much oxygen in the exhaust; and accordingly, the ECU cuts back on the fuel.

Real control systems may have more than 100 parameters, each with its own lookup table. Some of the parameters even change over time in order to compensate for changes in the performance of engine components like the catalytic converter. And depending on the engine speed, the ECU may have to do these calculations over a hundred times per second.

Performance Chips
This leads us to our discussion of performance chips. Now that we understand a little bit about how the control algorithms in the ECU work, we can understand what performance-chip makers do to get more power out of the engine.

Performance chips are made by aftermarket companies, and are used to boost engine power. There is a chip in the ECU that holds all of the lookup tables; the performance chip replaces this chip. The tables in the performance chip will contain values that result in higher fuel rates during certain driving conditions. For instance, they may supply more fuel at full throttle at every engine speed. They may also change the spark timing (there are lookup tables for that, too). Since the performance-chip makers are not as concerned with issues like reliability, mileage and emissions controls as the carmakers are, they use more aggressive settings in the fuel maps of their performance chips.

For more information on RENAULT fuel injector systems and other automotive topics, check out the links on the next page.
The call for reduction in pollution has been mandated by government′s policies worldwide. This challenges the engine manufacturer to strike an optimum between engine performance and emissions. However with growing technology in the field of fuel injection equipment, the task has become realizable. For past few years it has been the hot topic to improve combustion and emissions of compression ignition engines through optimizing the fuel injection strategies. Choosing between various injection strategies are potentially effective techniques to reduce emission from engines as injection characteristics have great influences on the process of combustion. For example, increasing the fuel injection pressure can improve the fuel atomization and subsequently improve the combustion process, resulting in a higher brake thermal efficiency, producing less HC, CO, PM emissions, but more NOx emission. Pilot injection help in reducing combustion noise and NOx emissions and immediate post injection may help in soot oxidation and late post injection helps in regeneration of diesel particulate filter. This article aims at a comprehensive review of various fuel injection strategies viz varying injection pressure, injection rate shapes, injection timing and split/multiple injections for engine performance improvement and emissions control. Although every strategy has its own merits and demerits, they are explained in detail, in view of helping researchers to choose the better strategy or combination for their applications.

One of the many reasons we love cycling is that it allows us to get outside and explore. But with winter at our doorstep, sometimes the weather is just plain awful or there’s just not enough time in the day. The next best option? A Spin class, of course.

Most studios offer a variety of class options—some as short as 20 minutes or as long as 90 minutes—so you’re always able to fit a workout into your schedule. Nowadays, there are even at-home magnetic spinning bike available that stream classes directly into your living room from companies like Peloton, NordicTrack, and Technogym. Peloton’s beginner-friendly classes, for example, teach participants the correct form and technique that will translate to every other level.

Plus, the work you do in a class—whether that’s at home or in a gym—complements your on-the-road training perfectly, according to Peloton instructor Jess King. “It’s an opportunity for you to play around with your training—there’s something for you to hear, learn, and experience that you can take with you back on the road. So why not dip into both worlds?” she says.

Spinning is one of those things that seems a bit intimidating if you’ve never done it before. But as long as you have access to a gym or a bike, you can take classes that range from beginner to expert, King says, each of which helps build the main muscle groups used for cycling and your cardiovascular system.

“We have this unique opportunity to create something for everyone,” King says. But most studios and instructors offer a variety of options that will suit your needs or experience level.

And if you’ve already got the stamina to climb hills and ride long outside, you’re that much more ready to conquer a Spin class. Both studios and at-home options offer longer, more advanced classes as well.

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It goes without saying that taking a Spin class is not the same as riding outside. While you can still experience similar terrain (hills and flat ground), King says in-studio and virtual Spin classes can feel more like a party than a workout.

“There’s music from all different decades—from classic rock to EDM—and we use interval training, tabata training, and heart rate training, so it’s still a great workout,” she says about Peloton, though competitors offer a similar experience.

A lot of times when you’re out on the road, it’s just you and the voice that’s in your head. That can be a good thing when you want to escape to nature and clear your mind, but it can be a bad thing when the voice is telling you to turn home. Being in a class setting changes things up—especially when you have the motivation of an instructor cheering you on. (Because let’s be real, there are times when you just really don’t want to do that interval workout on your own.)

“Spin gives you a new perspective on how to ride, breathe, and think about your body,” King says.

When you take an indoor cycling class, everyone from the instructor to the other participants are there to encourage and support you.

“Everyone is rooting for you—you’re not alone in this experience,” King says. “We’re using the bike as the medium for that connection and energy.”

And Charlee Atkins, C.S.C.S., former master instructor at SoulCycle and founder of Le Sweat, agrees. “[Everyone] is very supportive—they hold each other accountable and celebrate each other’s wins and losses,” she says. “They oftentimes can become an ‘extended family’ of sorts.”

It can be really tough to be out on your indoor cycle spinning bike alone, struggling to finish a particularly challenging ride. Sometimes your first instinct is to give up. But when there are other people around you, it makes you want to keep going and prove you can finish what you started. That’s exactly what taking a Spin class does. And that mindset can and will benefit you on the road, too.

If you’ve already found a great community of riders outdoors, indoor classes offer the same camaraderie and accountability, just in a different setting.

4. It’s a great total-body workout.
Not only does a Spin class benefit your muscles—everything from your legs to your core—but it’s also a great low-impact cardiovascular workout, which improves your blood flow, increases your stamina, boosts your mood, and prevents against chronic issues such as high blood pressure, heart disease, stroke, and diabetes, according to Mayo Clinic.

And because of this intense cardio workout, you’ll burn a ton of calories, too. While King says the average is about 400 to 600 calories per class, she’s seen some riders burn more if they’re going particularly hard and long.

Some indoor cycling classes even incorporate the use of hand weights to “promote upper-body work, since cycling is a predominantly lower-body workout,” Atkins adds. So in one 45-minute session, you can challenge your upper body, lower body, and core.

5. It’s convenient.
Riding outside can take a couple of hours to complete, and most people don’t have that kind of time during the week. So taking an indoor cycling class either at home, at a gym, or in a studio is a great option for when your schedule is packed, and you only have an hour or less to work out.

But don’t worry—exercising for a shorter amount of time doesn’t mean you aren’t reaping the same benefits as a longer workout. Many classes feature high-intensity intervals which help you build increased cardiovascular and muscular fitness in less time than a longer but steady-state ride out on the road.

6. It’s low impact.
Indoor cycling won’t beat up your joints like other forms of cardio such as running. “It’s great for people who are coming back from an injury,” says Atkins, because your hips, knees, and ankles won’t take all the impact. This makes it a great choice for those who aren’t yet functioning at 100 percent after getting hurt, older adults looking for a way to stay active without putting extra pressure on their joints, or those who suffer from arthritis.

7. You can make it your own.
Out on the roads, you can’t lower the grade of a mountain if you’re not up for climbing it that day. But the beauty of a Spin class is that you can customize it to your own needs. The Spin instructor is there to guide you, but you can always modify the workout.

For example, you don’t have to stay on the bike during the upper-body workout portion of the class if you feel safer on solid ground. You can also go slower if you need to—you don’t have to worry about getting dropped. And if the class motivates you to push yourself even harder, maybe try racing your friend next to you. Everyone in class is there to work out to the best of their ability while enjoying the motivational vibes of the group. So whatever you’re feeling, go ahead and do your thing.

8. It gives your bike a break.
Switching it up with some Spin classes will also give your commercial spinning bike a break from the elements, not just your body. Rain, dirt, and snow will take their toll on your components over time. Replacing just some of your workouts with Spin classes will give you the opportunity to buy and install new parts, or time to take your bike into the shop for a tuneup.

Spinning might look about the same as outdoor cycling or riding a stationary bike, but in many ways, it’s a far more intense workout—and one of the easiest to overdo.

First, there aren’t many (if any) breaks in spin class. “When you’re biking outside, you have to be aware of road dangers like water and cars, so you have to slow down at times,” says Dr. Maureen Brogan, an assistant professor of medicine at New York Medical College who has conducted research into spinning. Especially if you’re a novice road rider, it’s going to take some time before you’re comfortable enough on two wheels to really push yourself hard for long distances. That’s not the case on a spinning bike, where newbies can hop on and ride hard from the start.

Popular spinning studios like Flywheel and SoulCycle have their riders clip their feet into the stationary bikes. As long as the wheels turn, legs keep pumping. Combine this always-working aspect with the thumping music, enthusiastic instructors and energetic group atmosphere of most spinning studios, and it’s easy to get intense exercise and burn calories by the bucketful.

“The muscles you use on spinning bikes, the gluteus maximus and the quadriceps, are some of the largest in your body, so you’re using a lot of energy,” Brogan says—600 calories an hour, and sometimes more.

This puts spinning near the top of the list when it comes to high-intensity workouts. A study from Sweden found that one hour of spinning was enough to trigger the release of blood chemicals associated with heart stress or changes. While that may sound like a bad thing, these blood chemicals—or biomarkers—signal the heart is getting a good workout. “These kinds of findings have also been seen with prolonged exertion such as marathons,” says study author Dr. Smita Dutta Roy of Sahlgrenska University Hospital in Sweden. While more research is needed to tease out the risks or benefits associated with exercise of this intensity, she says that some of the biomarker shifts her team observed could lead to blood vessel repair and renewal.

It can also help improve body composition, decrease fat mass and lower blood pressure and cholesterol, says Jinger Gottschall, an associate professor of kinesiology at Penn State University. Some of her research has shown that high-intensity spinning can increase fitness levels even in trained athletes. “In every study we’ve done, we’ve seen increases in heart and lung capacity,” she says. She calls spinning “the optimal cardio workout,” and says you can get all the intensity of a treadmill or stair-climber without the impact.

The low-impact nature of spinning makes it great exercise for older adults or people recovering from orthopedic injuries, she adds. “Because you can adjust the resistance and moderate the pace and intensity of your ride, it opens the door for many people to participate,” she says.

But it’s also easy for people who are new to spinning to overexert themselves. “If you’re not used to vigorous exercise, or to exercising the large lower-body muscles involved in spinning, you can overdo it,” Brogan says. She’s a kidney expert by training, and some of her research has linked spinning to rhabdomyolysis, a condition in which muscles break down to the point that they release a protein that can poison the kidneys. “People have swollen legs or trouble walking, and sometimes they take aspirin or NSAIDs for the muscle pain, which is the last thing they should do because those can also damage the kidneys,” she says. Problems like this can set in a day or two after spin class, she says.

While overexertion is possible with any form of exercise, she says the risks during spinning may be higher—especially when you consider that some spinners lose up to a liter of water during an hour-long session.

Even for trained athletes, there’s some evidence that spinning too often may lead to trouble. A study in the Journal of Strength and Conditioning Research concluded that spinning may push some people past the threshold at which the exercise is beneficial. “If indoor cycling were used as an everyday training activity, it is possible that the overall intensity would be too high and possibly contribute to developing nonfunctional overreaching,” the authors of that study write. (“Nonfunctional overreaching” is sports science lingo for a workout that’s so strenuous it leads to fatigue and performance declines, rather than fitness improvements.)

Overall, spinning is exceptional exercise. But if you’re new to it, you need to ease in and give your muscles time to adapt to its intensity. Even if you’re an experienced athlete, pushing yourself to your limit the first or second time you get on a spinning bike may be risky, Brogan says. Even once you’ve found your spinning legs, daily sessions may still be overkill.

But if you’re looking for a high-intensity workout a few days a week—and especially if running or other forms of vigorous aerobic exercise hurt your joints—spinning may be the ideal way to keep your heart and body in shape.

The advent of troughed belt conveyors fundamentally changed industrial processing, increasing efficiencies, reducing labor requirements, improving safety, and streamlining production. These flexible devices have become the standard for moving product and material around a facility and are found in every industry imaginable.

While belt conveyors provide a reliable, efficient bulk handling solution, they can experience occasional problems. And when issues arise, they can wreak havoc on a production line. Below are some of the most commonly seen issues when working with belt conveyors, including what causes these problems and how to prevent them.

Note: This is not a comprehensive list and does not substitute for the expertise of a professional. Always consult your original equipment manufacturer or manual to ensure all necessary safety, maintenance, and troubleshooting guidelines are followed. Maintenance and storage procedures should always be carried out by a trained professional. FEECO does not make any representations or warranties (implied or otherwise) regarding the accuracy and completeness of this guide and shall in no event be liable for any loss of profit or any commercial damage, including but not limited to special, incidental, consequential, or other damage.
Carryback is the material that remains on the belt after discharge and is perhaps the most common struggle among conveyor pulley. Typically all conveyors experience carryback to some extent, but given its potential for serious consequences, keeping it to a minimum is essential.

WHY CARRYBACK IS AN ISSUE
Carryback creates a messy and potentially hazardous work environment, as it gets into the undercarriage and surrounding area of the conveyor. This can cause outages and increase the time devoted to cleaning and maintenance.

Not only does carryback create a mess, but material allowed to build up on rollers, idlers, and pulleys degrades these components, causing excessive wear. Further, a buildup of carryback can also cause belt tracking issues, potentially wearing and damaging the belt.

WHAT CAUSES CARRYBACK
Carryback is largely a result of the conveyed material’s characteristics and propensity for sticking. In general, a material with a higher moisture content is more likely to stick to the belt. Similarly, carryback can be more of a problem in humid environments where hygroscopic materials pull moisture from the air, increasing the likelihood of sticking.

Sticking can also occur when condensation is produced as a result of extreme temperature differences between the material and the belt.

HOW TO PREVENT CARRYBACK
The best way to prevent carryback is to utilize one or more belt cleaners. Belt cleaners can be installed at both the head and tail pulley and serve to ride against the conveyor belt, dislodging any material that may be adhered to the belt. These devices substantially reduce buildup on the belt, and depending on the level of carryback, several options may be appropriate. Common options include a self-cleaning tail pulley, return side belt plow (v-plow), and dual belt cleaners.

Routine cleaning should also be prioritized as part of a conveyor head pulley maintenance program in order to minimize any remaining buildup on components.

CONVEYOR BELT MISTRACKING
Tracking, or training, refers to the way in which the belt rides on the rollers. Conveyor belts should always track centrally. Mistracking occurs when the conveyor rubber belt rides unevenly on rollers, favoring one side over the other.
Like carryback, mistracking can cause several issues in a conveyor system. This includes uneven belt wear, belt damage resulting from catching or rubbing on surrounding infrastructure, material spillage, warped belting or belts that are not square, and more.

Mistracking is also recognized as a safety violation by the US Department of Labor’s Mine Safety and Health Administration (MSHA). When a belt is not tracking properly, areas that are normally safe can become pinch points, presenting a hazard to workers. Mistracking can also cause material to fall off of the conveyor, falling on to workers and equipment, or creating piles that present a safety risk.

WHAT CAUSES MISTRACKING
Since conveyor bend pulley are carefully balanced, any number of factors may be the source of mistracking, making it difficult to identify the origin of the problem. Potential causes of mistracking include improper idler spacing, seized or worn rollers, a misaligned frame, material buildup on any part of the conveyor, excessive belt tensioning, and a worn or damaged belt, to name a few.

HOW TO PREVENT MISTRACKING
The range of possible mistracking causes make a blanket solution to prevention impossible. There are, however, measures that can help to reduce the potential for this issue to occur.

Conveyors can fall out of perfect alignment through normal wear and tear. As a result, routinely inspecting alignment of the conveyor structure and its many components helps to prevent mistracking. Off-center loading can also create an alignment issue, so ensure that chutes are positioned centrally over loading areas.

Since mistracking can be caused by material buildup, it’s also important to keep the belt conveyor, idlers, and pulleys clean. This will reduce wear on components, which could also cause mistracking.

Slight off-tracking issues can be remedied by “knocking idlers,” a practice in which idlers are skewed a small amount to correct an off-tracking belt.

SLIPPAGE
Belt slippage typically occurs around the drive/head pulley and happens when the belt and pulley do not have enough grip to adequately turn the belt around the pulley.

WHY BELT SLIPPING IS AN ISSUE
Belt slipping reduces productivity and efficiency, causing process upsets, or preventing the proper amount of material from being conveyed. It can also cause belt wear and damage, and put added stress on the motor, resulting in premature failure.

WHAT CAUSES SLIPPAGE
There are several reasons why a belt experiences slipping. This includes:

Low temperatures (cold temperatures can reduce the amount of grip between the pulley and belt)
Improperly installed pulley lagging
Buildup on pulley
Inadequate belt tension
Worn head pulley
Smooth pulley surface
Load that is too heavy for conveyor
HOW TO PREVENT SLIPPAGE
There are several ways to prevent slippage. Maintaining an adequate belt tension is critical to preventing slippage. It’s important to note, however, that while over-tensioning the belt may seem like an easy fix, this should be avoided, as it can stretch and damage the belt, as well as put added stress on the motor.

When there is not enough grip between the pulley and the belt, consider installing lagging. Lagging is a material added to the surface of the pulley for increased traction.

Alternatively, a snub pulley may be installed. A snub pulley is simply an idler installed at a point which increases the arc between the belt and pulley to improve friction between the two.

MATERIAL SPILLAGE
Material spilling off of the conveyor is also a commonly encountered problem. While spillage can occur at any point along the conveyor path, not surprisingly, it is most common at load and transfer points.

WHY SPILLAGE IS AN ISSUE
As with other issues, material spilling off of the conveyor belt reduces productivity and efficiency, encourages product/material loss, and increases wear on equipment. Further, as mentioned, spillage can be a significant safety hazard, falling on employees and increasing the likelihood of employees slipping or falling.

WHAT CAUSES SPILLAGE
In general, it is not uncommon to see some level of material spillage. Excessive fugitive material, however, likely indicates an underlying issue. Typical causes of excess spillage include belt misalignment, belt damage or wear, high-impact loading, and chute misalignment.

HOW TO PREVENT SPILLAGE
Spillage in general is managed by a well-designed conveyor system. The use of skirtboards and dust pick-off points are useful in reducing the potential for material spillage.

Ensuring that chutes are clear and located centrally above the loading zone will also help to prevent spillage. Additionally, impact beds for heavy loading prevent the belt from sagging, which can also release fugitive material.

Keeping conveyors aligned and in proper working order will also help to prevent excess fugitive material from escaping, as any deviation from proper operation has the potential to spill material.

PREVENTION IS KEY
Any one of the aforementioned issues has the potential to cause serious problems: premature equipment failure, unexpected downtime, employee injuries, and more. Even if problems do not reach a high level of severity, however, they still represent unnecessary hazards and losses in productivity and efficiency. For these reasons, a preventative approach to conveyor problems is always the best policy.

Regularly inspect the steel cord conveyor belt to look for signs of trouble: excessive material spillage, abnormal sounds, visual indicators, or other abnormalities. Always ensure that the equipment, as well as the surrounding area, are kept clean. Replace conveyor components that begin to show signs of wear.

By taking these measures, the potential for unexpected downtime and lengthy repairs is greatly reduced.

CONCLUSION
Troughed belt conveyors offer reliable handling in nearly any setting, but they can occasionally exhibit issues, particularly if not kept clean and maintained; carryback, mistracking, slippage, and spillage are some of the most commonly encountered issues when working with belt conveyors. While each issue presents significant risk and potential for damage, these issues are largely prevented by keeping a close eye on conveyor operation and performance, and promptly addressing any issues that arise.

FEECO manufactures custom belt conveyors and conveyor systems for use in nearly every industry, with expertise around hundreds of materials. Our Customer Service Team offers a full range of services for conveyors, from replacement parts, to repairs, and even inspections and conveyor audits. For more information on our belt conveyors or conveyor parts and service support, contact us today!