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Zirconia: Taking Dental Restorations to the Next Level

Descripción:     Zirconia: Taking Dental Restorations to the Next Level     Since the introduction of porcelain-fused-to-metal (PFM) crowns in the 1960s, the dental industry has sought materials with both the esthetic value of porcelain, and the strength of noble metals to withstand the pressure of posterior occlusal forces.     Glass-ceramic materials that came along in the 1980s were confined to use on anterior teeth. In the early 2000s, researchers found that a toughened version of the metal zirconia met the strength requirements needed for posterior teeth, although the esthetics of the material left much to be desired.     Today, with improved technology, zirconia now rivals PFMs and all-ceramic restorations both for strength and beauty.     A member of the titanium family of metals, zirconia has multi-industry uses and is ideal for use in both anterior and posterior crowns where it fulfills functional requirements and can be custom shaded for quality esthetics.     Advantages     Zirconia is now the preferred material for crown and bridge fabrication, including implant-supported restorations. These are replacing metal-based restoration as the choice of most dentists, lab technicians, and patients. Because it can withstand occlusal forces without causing wear on opposing teeth, the material has quickly replaced full-metal and PFM’s as the material of choice.     Zirconia is more wear resistant than gold, retaining its shape and resisting the tendency to crack and erode by patients who brux. The flex strength value (MPa) of zirconia is more than twice that of traditional lithium disilicate (glass-ceramic) making it the ideal material for posterior crowns and bridges.     Recent Article: Benefits of Digitally Planned Implant Placement     While there is, as always with innovative technology, a learning curve for dentists new to working with zirconia, the techniques for tooth preparations is basically the same as for porcelain and glass ceramic materials. A more conservative preparation of the patient’s original tooth structure is a distinct advantage.     With zirconia, clearance may be as little as 1 mm, while lithium disilicate materials require 1.5 to 2mm and will not be as strong. A thicker chamfer is preferable to a feathered margin to provide for minimum thickness at the margin while retaining the ability to taper it to the prep.     Traditional impressions or digital impressions can be used with equal success.     Concerns     As with all new materials and technology, dental zirconia does have its drawbacks.     Many dentists are hesitant to use zirconia because there are fewer long-term research studies to assess its properties and compare the longevity of the material to gold, porcelain, and lithium disilicate. However, the studies completed thus far all reflect positively on the future of zirconia crowns.     There is also a lack of ability to bond the material to the preps. Though, that might be seen as an advantage by some, since only cement is needed to permanently seat the restoration. The hardness, while certainly considered one of zirconia’s advantages, might be a disadvantage when having to remove or access through them for endodontic treatment.     Recent Article: Why You Should Go Digital With IOS Dentistry     Chairside adjustments, while usually minimal, must be made safely, using diamond burs at slow speed with copious amounts of water, polishing wheels, and cones specifically designed for use with zirconia.     Do not use carbide burs or diamonds at high-speed for adjustments due to microscopic fractures that can occur from the impact of the burs on the material.     Ready to Try?     The future of zirconia use in dentistry is unlimited.     Gold and other noble metals used for decades are slowly dying out due to not only prohibitive cost, but also lack of demand by consumers. Zirconia more than fills that gap.     Researchers continually improve the translucency of these restorations, making them legitimate rivals to all-ceramic for beauty and surpassing other dental materials for strength and durability.     Here are First Choice Dental Lab, we specialize in all types of zirconia restorations, including full-contour and esthetic anterior.     Ship us your case today by clicking HERE, or send digital scans HERE to give zirconia restorations a try!     Want to learn more? Complete the form below and let us help you plan your next restoration!     Pre shaded zirconia has become popular with dental laboratories due to the time-savings and shade consistency the base shade provides. With pre-shaded zirconia there is no need for laboratory technicians to shade each unit in the green stage, saving production time and freeing them up to produce more units. However, standard pre-shaded zirconia systems require the dental laboratory to stock an inventory of 16 shades, each in a large selection of disc thicknesses to cover all unit shades and sizes. Furthermore, you can mill only one shade at a time, thus tying up your mill.     The ArgenZ Anterior Value Shaded Disc System is a collection of pre-shaded super translucent zirconia that covers all 16 shades of the VITA Classic shade guide with just six value-shaded discs. Each disc covers 2-3 shades based on value and chroma, requiring much less inventory and mill time. No green stage shading is required. You simply design, mill, sinter, and stain and glaze.     The discs are as follows: ? Disc 1: Shades A1, B1 ? Disc 2: Shades A2, B2, A3 ? Disc 3: Shades C1, D2 ? Disc 4: Shades C2, D3, D4 ? Disc 5: Shades A3.5, B3, B4 ? Disc 6: Shades A4, C3, C4     Hue and Chroma Shading     Similar to the 16-disc shade systems, each ArgenZ Anterior Value Shade Disc group will be approximately one-half shade lighter than the lightest shade in that group. This makes it easy for the technician to change hue, adjust chroma intensity, and create a good incisal transition zone with external chroma stains.     Value     Traditional all ceramic systems are low in value, especially the light high value shades such as A1. The ArgenZ Anterior Value Shaded System is formulated to deliver a true value to match the guide.     Incisal Translucency and Appearance     The translucency of ArgenZ Anterior and the additional light refraction from the cubic ZR phase results in a natural incisal translucency requiring little to no incisal staining. Units with thicker incisals may require some minor incisal enhancement with incisal enhancement stains.     Stain and glaze system     Many companies make a low fusing fluorescent stain-and-glaze system designed primarily for all-ceramic systems. The most important stains in the kits are the A, B, C, and D chroma stains. These stains are essential to stain up to the next chroma or shade level in each shade group. Incisal stains or intensive blue stains can be customized with black, white, or violet to make any incisal enhancement color needed.     Firing Temperatures     Stains do not penetrate zirconia, so it is not necessary to fire above 800°C. The systems the author uses allow stains to be fired at 750°C (fully melting) and glazes to be fired at 730°C.     Die Shading System     Units must be seated on a die for final staining to match the shade guide. Due to the translucency of anterior zirconia, the final shade is slightly affected by light diffusion and the color of the underlying die and preparation. The anterior unit will appear to have a higher value and slightly more chroma when seated on a die.     Using a die color coating system to match preparation shades (stump shades) is recommended. Preparation coloring systems contain a variety of colors to match light to dark shades. If you do not have guidance on preparation colors (picture or preparation shade), match the die shade color to the prescribed base shade.     Glass Ceramic Materials     Glass ceramic materials have the same chemical compositions as glasses but differ from them in that they are typically 95-98% crystalline by volume, with only a small percentage vitreous. The crystals themselves are generally very small, less than 1μm and most often very uniform in size. Furthermore, due to their crystallinity and network of grain boundaries, they are no longer transparent.     Production of Glass Ceramic Materials     Glass ceramic components are formed using the same processes that are applicable to glass components. To convert them from a vitreous glass material into a crystalline glass ceramic material they must be heat treated or devitrified.     Devitrification can occur spontaneously during cooling or in service, but is most commonly incorporated to produce glass ceramics. It involves heating the formed glass product to a temperature high enough to stimulate crystals to nucleate throughout the glass. The temperature is then increased, which induces growth of the nuclei, crystallising the remaining glass.     Nucleation requires a critical number of atoms converging to form a nucleus. When the nucleus reaches critical size, nucleation occurs. In many glass compositions, nucleation is hampered by the fact the material is silica-based and highly viscous, making it difficult for the required atoms to come together. The crystal compositions can also be complex making nucleation difficult. These factors aid glass forming and cooling without crystallisation.     The devitrification heat treatment must be carefully controlled to ensure the maximum number of nuclei are formed and that these nuclei grow into a uniform fine crystal structure. In order to obtain a high concentration of nuclei throughout the structure, it is common to add a nucleating agent to the glass composition.     How are resin frameworks made? CAD design software is used to design the framework and then it is milled out using milling machines. The resin clasps engage the origin of the undercut rather than the terminal third to allow three to four times the retention of metal. In addition to a superior esthetic color, the resin clasps can be placed more gingival, further increasing its natural appearance.     Acetal dental can also be used for tooth shaded clasps on acrylic partials as well as a single and two tooth posterior unilateral partials. The latter situation is a great way to make an interim partial for a patient having implants placed.     For these reasons, we believe in recommending acetal resin to other dentists and our customers. It’s a strong, versatile material that has proven to be superior to using metal clasps and frameworks. We are committed to researching and finding the best products for our dentists.     Roland DGA Corporation’s three Diamond-Coated Dental Milling Burs, meant to be used with Roland’s DXW-50 zirconia milling machine, are specially engineered for precise performance, maximum durability, and longer life. Extensively tested for tolerances, Roland’s new milling burs are available in three different sizes – 2 mm, 1 mm and 0.8 mm – allowing dental professionals to choose an ideal tool for every milling strategy.     The proprietary design of every Roland Diamond-Coated Dental Milling Bur enables the user to produce up to 10 times the number of units that can be milled with a standard carbide model. Because they are fully compatible with Roland’s existing carbide tools, users can switch to the new tools without any changes in the CAM software, making the upgrade a true “plug-n-play” solution.

Fecha de Publicación: 28-09-21

Cook Your Meat in a Beer Cooler

Descripción: Cook Your Meat in a Beer Cooler     By this point, there is absolutely no question that the method of cooking foods at precise low-temperatures in vacuum-sealed pouches (commonly referred to as "sous-vide") has revolutionized fine-dining kitchens around the world. There is not a Michelin-starred chef who would part easily with their Polyscience circulators. But the question of when this technique will trickle down to home users—and it certainly is a question of when, and not if—remains to be answered.     The Sous-Vide Supreme, introduced last winter, and of which I am a big fan, is certainly a big step in the right direction. But at $450, for most people, it still remains prohibitively costly. In an effort to help those who'd like to experiment with sous-vide cookery without having to put in the capital, a couple weeks ago I devised a novel solution to the problem: Cook your food in a beer cooler.             "a beer cooler is just as good at keeping hot things hot as it is at keeping cold things cold"     Here's how it works: A beer cooler is designed to keep things cool. It accomplishes this with a two-walled plastic chamber with an air space in between. This airspace acts as an insulator, preventing thermal energy (a.k.a. heat) from the outside from reaching the cold food on the inside. Of course, insulators work both ways. Once you realize that a beer cooler is just as good at keeping hot things hot as it is at keeping cold things cold, then the rest is easy: Fill up your beer cooler with water just a couple degrees higher than the temperature you'd like to cook your food at (to account for temperature loss when you add cold food to it), seal your food in a plastic Ziplock bag*, drop it in, and close your beer cooler until your food is cooked. It's as simple as that.     How to Clean Your Beer Taps     One of the best options for cleaning your beer taps is to use a cleaning kit. A beer tap cleaning kit comes with all the equipment and chemicals you need to clean your system, and they come with easy-to-follow instructions. Instead of cleaning the taps themselves, many bar owners choose to use a cleaning service. Services are quick and convenient, and they ensure that your system is cleaned efficiently and regularly.     How Often Should Beer Lines Be Cleaned?     How regularly you should clean your beer tap system will depend on the volume of your business. High-volume nightclubs, sports bars, and banquet halls should clean their beer tap lines every week or two. Lower volume establishments only need to clean their draft lines every 2 or 3 weeks.     How to Tap a Keg     Beer Keg is an essential skill for bartenders. Here is how you can tap a keg in three easy steps:                Attach the coupler to your gas cylinder. Make sure that you have the correct coupler for the beer you're serving, as using the wrong coupler can affect the gas pressure and how your beer pours.                Open the gas valve and adjust the gas pressure. Most light beers, ales, and lagers should be dispensed at 10 - 12 PSI. Darker beers like porters and stouts should be dispensed at higher pressure levels, closer to 25 - 30 PSI.                Take the dust cover off your keg. Attach your beer tap to the keg, ensuring that it is securely locked in place.     Common Problems and Solutions for Beer Tap Systems     Is there an issue with your beer tap system? Most issues with beer tap systems are a result of improper temperature, improper pressure, or cleaning issues. So before you call a technician next time you have an issue with your beer lines, check out this list of common problems and solutions.     How to Choose the Right Draft Beer Tower     There are many reasons one would want to upgrade their draft beer tower on an old kegerator or converted freezer. It might be that the kegerator you bought came with a cheap plastic tower. It may be that the tower you have does not have beer industry standard fittings. It may be that you want to serve something like Guinness? or cold brewed coffee and you need stout faucets to get the restricted flow necessary for that application. Maybe you find yourself filling taller glasses or growlers and need a tower with increased height to accommodate them. Perhaps you are tired of your faucets always being stuck and you're ready to switch to Perlick faucets for their forward-seat design that ensures smooth operation every time. You might just want to make sure that you have 100% stainless steel contact to make sure your system is as sanitary as possible and suitable for serving wine or cider.     Tower Options     Whatever the reason, Beverage Factory has a plethora of draft beer kegerator available with a host of finishes and an assortment of faucet options to choose from. We have basic single faucet towers all the way up to elaborate multi-faucet ceramic towers. We've got customizable T-Style towers that have the same column diameter as a standard kegerator tower, allowing you to easily switch them out with your existing tower.     Generally, switching out your tower is as easy as unscrewing your old tower and screwing in your new one. Something to consider would be how your tower is currently connected. If, for example, you have a 2.5" diameter tower or a tower with a base that screws into the top of your kegerator and you want to replace it with a tower that has a 3" diameter, you will need to drill new screw holes to attach the new tower to the top of your kegerator. The kegerators that we have seen do not have coolant lines in the top of the cabinet so you can be 99% sure you're not going to damage anything by drilling into the top, but if you want to be 100% sure, it's a good idea to call the manufacturer of the model you're working with to ask.     Another thing to consider is how wide the hole in the top of your kegerator is and if it will allow you to drop the beer line through the hole without removing the fittings on the end. If you are upgrading from a single faucet tower to a multi-faucet tower, you may not be able to push all the lines through without detaching one or all of the fittings. You can try pulling the nut back away from the end of the line to push the tube through and then squeezing the nut through afterward, but detaching and re-attaching the fittings may be the only answer. Usually, this just means removing the clamp that holds the beer line onto the hose nipple and then cutting the hose off to release the hose nipple and hex/wing nut that attaches it to your keg coupler. Once they are removed and the lines are pushed through the hole, you can re-attach them with a new clamp. If you are having a hard time getting the hose to slide over the hose nipple, putting the end of the hose in boiling water will make it more pliable. If, for some reason, you find that you cannot reuse the fittings you have removed, we have plenty of new fittings available.     There are a few kegerator brands out there that do not use industry standard parts, so our industry standard fittings may not fit on the non-industry standard coupler that came with your kegerator, but we've got plenty of new keg couplers as well.                    Dispenser Types                           With beer dispenser, the beverages are kept inside the pressurized kegs until you pull the tap lever and pour it. It isn’t magic that pulls the brew through the hoses, it is science. Kegerators dispense the beverages using either CO2 or nitrogen gas.                          CO2 is the most common option for home brewers and beer aficionados. The fermentation process creates a natural level of CO2 when making the beer. Using CO2 to lift the brew to the tap is completely flavorless and preserves the natural carbonation of the beer, helping it maintain freshness in the keg longer. This is closer to the direct-pour taste, right out of the keg.                        Nitrogen dispensers are commonly associated with dark beers, like stout or porters, but also help preserve flavors in other beverages like wine or coffee. They produce smaller bubbles in the drink as it is dispersed and result in a “creamy” effect for some brews. When poured with a slow-pour, stout faucet, it produces a thicker foaming head on the beer.     Beer aficionados, coffee addicts, and wine connoisseurs, consider every detail in pursuit of their passions. How their drinks of choice are served can have an impact on flavor, and some cold beverages just taste better out of a tap. Kegerators keep beverages fresh, perfectly aerated, and always at the ideal serving temperature.     All it takes to experience your favorite on-tap drinks at home is a keg to pour from, the appropriate dispenser set up, and a refrigerator to keep it cool, which is exactly what you get with a beer kegerator. These specifically designed refrigerators not only hold multiple sized kegs of your chosen beverage, they do so at a specific temperature, alongside the tanks that allow it all to be dispensed directly from the keg, with just a pull of a faucet lever. It is the easy, classy way to enjoy your favorite beverage at home.

Fecha de Publicación: 28-09-21

What Is Microfiber Leather

Descripción:     What Is Microfiber Leather     Microfiber leather is an abbreviation of ultrafine fiber PU synthetic leather. It is a non-woven fabric made of three-dimensional structure network by carding acupuncture with microfiber staple fiber. After wet processing, PU resin impregnation, alkali reduction, and dermabrasion and polishing And other processes eventually make microfiber leather. It is made by adding ultra-fine fiber to PU polyurethane, which makes the toughness, air permeability and abrasion resistance further strengthened; it has extremely excellent abrasion resistance, excellent cold resistance, breathability, and aging resistance. Eco-friendly, Comprehensive performance beyond real leather. Widely used for automotive, garment, bags, sofa, shoes, boots, basketball, belt, jewellery box and so on. We are specialize in microfiber leather production manufacture.We provide the optimal leather options, the best leather substitute and best leather alternatives for automotive seat covers and interiors, furniture & sofa upholstery, footwear and shoes, bags, garments, gloves, balls, etc.     While synthetic leather were once considered not suitable for high quality shoes,  PU microfiber leather has changed how shoes are made.     Microfiber leather is designed to hold up against weather conditions and the wear and tear of walking and running over an extended period of time.     They can retain their form very well, and thus are usually very durable if cared for properly. They're also more water-resistant and lighter than real leather, making them great for long wear and outdoor activities.     We found this video, below, that tests how durable shoes made with suede microfiber leather are. Check it out!     Microfiber leather, or micro fiber leather, is the highest quality grade synthetic leather (faux leather or PU leather), a high-tech simulation of high-end leather material. WINIW Microfiber Leather is simulated the structure of natural leather, using sea-island superfine micro fiber (ultra-fine fiber bundle), and high-grade polyurethane resins as raw materials, using needle punched nonwoven technology of 3D structure, has a lot of similar characters as natural leather, however better physical & chemical performance, has been widely popular around the world. Because of superior performance, WINIW microfiber synthetic leather has been the best leather alternatives and the optimal leather substitute, material, best vegan leather and eco leather, can replace natural leather perfectly!     Compared to natural leather, microfiber synthetic leather has many excellent qualities, such as chemical resistance and physical and mechanical properties. However, preparation of microfiber synthetic leather with a high water vapor transmission rate (WVT), moisture absorption and wearing comfort property is still a challenge. In this study, we prepared thermoplastic polyurethane (TPU)/sulfonated polysulfone (SPSf) electrospun nanofibers and applied them to a microfiber synthetic leather base (MSLB). The effects of TPU/SPSf nanofiber content on the structure and properties of the MSLB were investigated. The results indicated that the TPU/SPSf nanofibers with an average diameter of 0.12?μm were well distributed at all directions in the MSLB. Differential scanning calorimetry analysis showed four Tg peaks, further demonstrating the existence of TPU/SPSf nanofibers. With the increase of TPU/SPSf nanofiber content from 0 to 30?wt%, the contact angles decreased gradually from 111.64° to 67.07°, leading to 55.19% improvement in the WVT value (from 2868.96 to 4452.24?g/(m2?24?h)) and 26.25% improvement in the moisture absorption (from 628.70% to 793.75% mm/s). Simultaneously, when the nanofiber content was 30?wt%, the nanofibers tended to bundle and 6.79% decrement of air permeability was observed. Specifically, the softness of the MSLB was improved by 88.55%. Moreover, the thermal stability and the tear strength were also obviously enhanced. Consequently, this research provided a feasible and promising way to prepare a high-performance MSLB using TPU/SPSf nanofibers.     The difficulty in dyeing microfiber base filled with ordinary polyurethane presents a significant challenge in maintaining the uniformity and highly realistic appearance of the resulting products. In the present study, a type of acid-dyeable polyurethane (PU-MDEA; MDEA=N-methyldiethanolamine) was synthesized, and its chemical structure and dyeing properties were investigated. Nuclear magnetic resonance analysis indicated that cationic groups were successfully incorporated into the PU-MDEA backbone via chain extension using MDEA. The amorphous nature of PU-MDEA was determined by differential scanning calorimetry, X-ray diffraction, and polarizing optical microscopy. Owing to the strong binding between these cationic groups and acid dye, as well as the reduced resistance to dye penetration, PU-MDEA showed better dyeability toward the acid dyes studied herein when compared with the control sample (microfiber synthetic leather filled with ordinary polyurethane). The adsorption isotherm experiment revealed that the dyeing process conformed to the Langmuir model, thereby indicating that the acid dyes attached to PU-MDEA via strong ionic bonding rather than van der Waals forces or hydrogen bonding. Additionally, it was found that the wastewater resulting from the dyeing of the microfiber synthetic leather filled with PU-MDEA exhibited environmentally friendly characteristics when compared with that displayed by the control sample (microfiber synthetic leather filled with ordinary polyurethane). Thus, the current results show the potential of PU-MDEA, as a filler, in the manufacture of microfiber synthetic leather to achieve fast dyeing rate, high dye uptake, and good color fastness, thereby improving the uniformity and highly realistic appearance of the resulting products.     Bonded leather is called ‘leather’ because it incorporates scraps of leather remnants, which comprise between 10-20% of its content. The scraps of leather are made into a pulp and stuck to a fibre or paper backer which is then coated with polyurethane and embossed to give it the appearance of genuine leather.     The price of an article is an immediate indication as to whether you are buying genuine leather. At a glance, bonded leather may look like the real thing but it will feel thin to the touch and will lack the softness of real leather, it may also exude a chemical smell.     WHAT IS BONDED LEATHER MATCH?     This term refers to the ability of bonded leather manufacturers to replicate the appearance of real leather, although it is likely that the product may be dyed in a striking range of unnatural colours.     For most people this will be a choice dictated by the comparative low cost of the product; some may choose bonded leather because it can be regarded as environmentally friendly, in so much as it uses left overs and does not involve additional farming and, potentially, reduces landfill. The product is also easy to clean and is likely to come in a wide range of design options.     Bonded leather should be wiped with a clean damp cloth and wiped dry with a different cloth. Spilt liquids should be cleaned immediately but no detergents or abrasive cleaners should be used. Non-alkaline cleaners and non-detergent soaps can be used but the material should always be tested for colour fastness on a small unobtrusive area first.     HOW DURABLE IS BONDED LEATHER?     Bonded leather is not a durable product. Generally, furniture made from bonded leather is likely to peel and crack within two to five years.     WHAT CAUSES BONDED LEATHER TO PEEL AND CRACK?      Bonded leather is a non-elastic material; therefore, it has a tendency to crack with use, strips of polyurethane and leather will then start to peel away from the backing.     WHY IS BONDED LEATHER BAD?     Compared with leather, bonded leather has a very short lifespan. It is prone to cracking and peeling and once it has deteriorated beyond a certain point it is impossible to repair. Although a bonded leather may be cheaper than real leather, it’s short life span means that in the long run the cost of replacing a bonded leather item can be more expensive. There is also the argument that this also makes it less environmentally friendly.     HOW TO REPAIR BONDED LEATHER       There are repair kits on the market which enable you to make small repairs to bonded leather. The affected area must be sanded to remove any protruding bits of leather, a patch can then be dyed to match or the fabric under the peel can be dyed and sealed to stop further peeling. The resulting repair will be noticeable but will be an improvement.     HOW TO FIX BONDED LEATHER SCRATCHES       First clean the area with a white cloth to ensure that no dye is transferred. Then mix a leather repair solution together with an appropriate tint. Add a small quantity of the mixture to the affected area and around the affected area. Then place leather grained paper, supplied with the kit, over the area and gently iron with a warm iron, this will transfer the pattern to the repair. Be careful to ensure that the iron is not too hot because it may discolour or damage the bonded leather. For minor scratches, it may be possible to affect a repair with the use of shoe polish. You should also check any new products on a small inconspicuous area of the leather item first.     Top Grain leather is the second highest grade quality of leather and is the lower part of the top layer of the hide. One removed it is sanded and refinished. It comes in two grades, aniline, which is natural soft leather which is vulnerable to stains and semi-aniline which has a protective coating. Top Grain leather is comprised of twelve to fourteen percent water and consequently it adjusts to body temperature: it is cool in summer and warm in winter. With bonded leather the reverse is the case.     BONDED LEATHER VERSUS REAL LEATHER      Real Leather, also referred to as Genuine Leather is the third grade of leather, taken from the lower, thinner layer of the hide. The surface is then reworked to resemble a higher-grade leather. It is not as tough as Full grain leather or Top Grain leather but is considerably more durable than bonded leather.     BONDED LEATHER VERSUS FAUX LEATHER      Faux leather, sometimes referred to as Pleather, contains no animal products and is made from polyurethane. It can be embossed with any texture and looks and feels like genuine leather. It is water resistant and easy to clean. Unlike bonded leather it does not crack or fade in sunlight, it is however, easy to tear or puncture. It is also considered less environmentally friendly due to the chemicals and toxins used in its production – although this varies depending on the exact process and materials used to produce it.     BONDED LEATHER VERSUS DURABLEND     Durablend is a low-cost leather alternative, similar to bonded leather and comprising of 57% polyurethane, 26% poly/cotton and 17% leather shavings. It is the trademark product of Ashley Furniture. Customer reviews suggest that it shares similar weaknesses with bonded leather in so much as it scratches easily and is prone to cracking.     BONDED LEATHER VERSUS VINYL      Polyvinyl chloride, popularly known as Vinyl or PVC is a faux leather which has been produced since the 1940’s by chemical companies like DuPont. It is used for shoes, car interiors and upholstery. Not as breathable as bonded leather, skin tends to stick to its surface, which makes it unpleasant seating in hot weather, it is easy to clean and maintain. Like bonded leather it cracks with use and is easy to puncture.     BONDED LEATHER VERSUS MICROFIBER      A much more sophisticated form of faux leather: polyurethane resin and ultra- fine microfiber leather for automotive are combined to replicate the microscopic structure of leather. The complexity of its construction mean that it is more expensive than other faux products but it does have a number of advantages over bonded leather. It doesn’t scratch or tear and is non-fading. It breathes like real leather but it also has ant -bacteria and anti-mildew properties. Unlike bonded leather it is completely odourless.     BONDED LEATHER VERSUS REXINE      Rexine is the registered trademark of a British artificial leather which has been produced since the 1920’s. Essentially a cloth backing is coated with cellulose nitrate and embossed to produce the illusion of leather. Primarily used for car interiors this is now regarded as retro faux leather and as such is sort out by collectors.     BONDED LEATHER VERSUS BICAST     Bicast is constructed using a split leather backing to which a layer of polyurethane is applied. The surface is then embossed to give the appearance of leather. It shares many of the qualities of bonded leather: it has a consistent texture and is easy to clean and maintain but it doesn’t breathe like leather and it lacks strength and durability.     BONDED LEATHER VERSUS LEATHERETTE      Leatherette is a plastic based synthetic leather. Unlike bonded leather it does not scratch and it does not fade in sunlight. Like most faux leather, it does not breathe and is unpleasant next to the skin. Although it might be the preferred choice of those who don’t like to use animal products, it is made from non- biodegradable, non-renewable materials and is therefore considered less environmentally friendly.    

Fecha de Publicación: 27-09-21

Cast Iron Pipe

Descripción:   Cast Iron Pipe     Cast iron pipes can fail in many modes which in general can be summarized into two categories: loss of strength due to the reduction of wall thickness of the pipes, and loss of toughness due to the stress concentration at the tips of cracks or defects. Even in one category there can be many mechanisms that cause failure. The strength failure can be caused by hoop stress or axial stress in the pipes. A review of recent research literature (Sadiq et al., 2004; Moglia et al., 2008; Yamini, 2009; Clair and Sinha, 2012) suggests that current research on pipe failures focuses more on loss of strength than loss of toughness. As was mentioned in Section 3.3.7(b), the literature review also revealed that in most reliability analyses for buried pipes, multifailure modes are rarely considered although in practice this is the reality. Therefore the aim of this section is to consider multifailure modes in reliability analysis and service life prediction for ductile iron pipe. Both loss of strength and toughness of the pipe are considered. A system reliability method is employed in calculating the probability of pipe failure over time, based on which the service life of the pipe can be estimated. Sensitivity analysis is also carried out to identify those factors that affect the pipe behavior most.     Buried pipes are not only subjected to mechanical actions (loads) but also environmental actions that cause the corrosion of pipes. Corrosion related defects would subsequently cause fracture of cast iron pipes. In the presence of corrosion pit, failure of a pipe can be attributed to two mechanisms: (i) the stresses in the pipe exceed the corresponding strength; or (ii) the stress intensity exceeds fracture toughness of the pipe. Based on these two failure modes, two limit state functions can be established as follows.     Steel pipe is manufactured by the pit, horizontal or centrifugal method. In the vertical pit method, a mold is made by ramming sand around a pattern and drying the mold in an oven. A core is inserted in the mold and molten iron is poured between the core and the mold. In the horizontal method, a machine is used to ram sand around horizontal molds that have core bars running through them. The molten iron is poured into the molds from multiple-lipped ladle designed to draw the iron from the bottom to eliminate the introduction of impurities. In the centrifugal method (Figure 3.4), sand-lined molds are used that are placed horizontally in centrifugal casting machines. While the mold revolves, an exact quantity of molten iron is introduced, which, by action of the speed of rotation, distributes itself on the walls of the mold to produce pipe within a few seconds.     Many cast iron pipes made towards the end of the nineteenth century are still in use; their walls were relatively thick and not always of uniform, ‘Spun’ grey iron pipes were formed by spinning in a mould and produced a denser iron with pipes of more uniform wall thickness; they comprise a large proportion of the distribution mains in many countries. Three classes of such pipes were available: B, C, and D for working pressures of 60, 90, and 120 m respectively; classes B and C were more widespread. Carbon is present in the iron matrix substantially in lamellar or flaky form; therefore, the pipes are brittle and relatively weak in tension and liable to fracture. The manufacture of grey iron pipes has been discontinued in most countries, except for the production of non-pressure drainage pipes.     Since cast iron pipes are deteriorating rapidly and causing so many maintenance problems (Section 4.3.2), the distribution network is currently undergoing an extensive replacement scheme with old, leaking and corroded cast iron pipes being replaced by MDPE and uPVC. These new plastic pipe materials are thought to support fewer bacteria than the old hubless cast iron pipe. Their surface is smoother and therefore the surface area smaller and they are not subject to corrosion or biodeterioration.     In addition, the effectiveness of a disinfectant is greatly influenced by the pipe material. Biofilms grown on copper or PVC pipe surfaces were inactivated by a 1 mg/l dose of free chlorine or monochloramine. However, on iron pipes 3-4 mg/l of chlorine or monochloramine was ineffective in controlling the biofilm (LeChevallier et al., 1990) because, as discussed before, the chlorine will preferentially react with the iron surface (LeChevallier et al., 1993). It appears that the option of changing pipe materials to ones with lower biofilm-forming potentials would reduce the biofilm problem.     Many cast iron pipes made towards the end of the 19th century are still in use; their walls were relatively thick and not always of uniform, ‘Spun’ grey iron pipes were formed by spinning in a mould and produced a denser iron with pipes of more uniform wall thickness; they comprise a large proportion of the distribution mains in many countries. Three classes of such pipes were available in the UK: B, C and D for working pressures of 60, 90 and 120 m, respectively; classes B and C were more widespread. Carbon is present in the iron matrix substantially in lamellar or flaky form; therefore, the pipes are brittle and relatively weak in tension and liable to fracture. The manufacture of grey iron pipes has been discontinued in most countries, except for the production of non-pressure drainage pipes.     Lead joint (a) is accomplished by melting and pouring lead around the spigot in the bell end of the pipe. After the lead has cooled to the temperature of the pipe, the joint is caulked using pneumatic or hand tools until thoroughly compacted with the caulking material and made water tight.     Cement joint (b) is started at the bottom with the cement mixture, and the mixture then caulked. Pipe with cement joints must not be filled with water until after 12 h has elapsed.     Roll-on joint (c) requires a round rubber gasket that is slipped over the spigot before it is pushed in the bell. Braided jute is tamped behind the gasket, after which the remaining space is filled with a bituminous compound.     Push-on gasket joint (d) is made by seating a circular rubber gasket inside the contour of the socket bell. The slightly tapered pipe end permits the gasket to fit over the internal bead in the socket. A special lever action tool, manually operated, then allows the bell and spigot past the gasket, which is thereby compressed as it makes contact with the bottom of the socket.     Mechanical joint and pipe joint should be thoroughly cleaned to remove oil, grit, and excess coating and then painted with a soap solution. Cast iron gland is then slipped on the spigot end with the lip extension toward the socket (or bell) end. The rubber gasket, also painted with the soap solution, is placed on the spigot end but with its thick end toward the gland. The entire section of the pipe is pushed forward to seat the spigot into the bell; the cast iron gland is moved into position for bolting.     The Putney gas explosion was a real wake-up call, and accelerated the replacement of old gray ductile iron pipe fittings by polymers such as medium-density polyethylene (MDPE), high-density polyethylene (HDPE), and unplasticized polyvinylchloride (UPVC). HDPE has a tensile strength of ≈20–37 MN m?2 (which is more than adequate for typical internal pressures). Most importantly, though, it has a Young’s modulus which is ≈150–300 times less than cast iron. This means that HDPE pipes can deflect under misalignments of the kind experienced in the Putney explosion without reaching the fracture stress. Even better, over a long time the polymer also creeps, which further dissipates the stresses caused by misalignment. Polymers are also very resistant to corrosion, so should last indefinitely in the ground.     But how are lengths of polymer pipe joined together? The following clip shows how:     http://www.youtube.com/watch?v=83PTUoFBq9s&feature=related     The steps in the process are shown in Figure 27.11. First, the ends of the pipe to be joined are machined flat and parallel using a double-sided rotating disk planer. Then the ends are heated with an electric hotplate. Finally, the hot faces are pushed together using a hydraulic ram. The softened thermoplastics fuse together, making a high-strength leak-proof joint. This is a quick, reproducible method, which requires little skill on the part of the operator—in marked contrast to the lead-filled spigot-and-socket joints of the old cast iron system. Figures 27.12 and 27.13 show an alternative joining method, where one end of the pipe has an enlarged bore into which the mating pipe can be inserted. This overlapping joint can then be fixed and sealed with polymer adhesive. It would be hard to envisage any replacement materials so well adapted to this challenging environment than thermoplastics.     The earliest oil pipelines in the United States, laid in the 1860s, were typically constructed of 2-in cast-iron pipe threaded and screwed together in short segments. Oil was propelled through the pipeline using steam-driven, single cylinder pumps, or by gravity feed. These early pipelines, seldom more than 15 mi in length, were prone to bursting, thread stripping at the pipe joints, and frequent pump breakdowns mainly due to the percussive strain on the lines caused by each stroke of the pump which “resembled the report of a rifled gun.” Development of the four-cylinder Worthington pump revolutionized the transportation of petroleum by pipeline with its constant flow and uniform pressure (The Engineering and Building Record, 1890; Scientific American, 1892; Herrick, 1949; Williamson and Daum, 1959).     By the 1870s, a 2000-mi network of small-diameter gathering lines connected the oil-producing areas with regional refineries and storage points on the railroads and rivers where the oil could be shipped to refineries via railcars or ships and barges. Typical crude oil trunk lines were constructed of 18-ft sections of lap-welded wrought steel pipe fittings 5 or 6 in in diameter joined with tapered, threaded joints manufactured specifically for pipeline service. The pipe was generally buried 2 or 3 ft below the ground surface. Worthington-type pumps were used as the motive power for the lines, and the pumps were powered by steam generated by coal-fired boilers. Pump stations were spaced as needed to maintain the flow of oil over the terrain crossed by the lines. At the pump stations, oil was withdrawn from the lines and passed through riveted steel receiving tanks some of which were 90 ft in diameter and 30 ft high holding about 35,000 barrels (The Engineering and Building Record, 1890; Scientific American, 1892; Herrick, 1949). Diesel-powered pumps began to replace steam power around 1913–1914 (Williamson et al., 1963).     It was not until May 1879 that the Tidewater Pipe Company, Ltd. began operation of the first long-distance crude oil pipeline covering the 100 mi between Coryville and Williamsport, Pennsylvania, to connect with the Reading Railroad. The line was constructed of 6-in wrought-iron pipe laid on the surface of the ground (except when crossing cultivated land) and relied on only two pumping stations, one at Coryville and the other near Coudersport. The expansion of the oil under the hot summer sun caused the line to shift as much as 15–20 ft from its intended position, knocking over telegraph poles and small trees, but no serious breaks occurred. In the spring of 1880, Tidewater buried the entire line (Williamson and Daum, 1959).     The success of the Tidewater pipeline set the pattern for the construction of other long-distance crude oil “trunk” lines which sprang up in the early 1880s connecting the oil regions of Pennsylvania with refining centers in Cleveland, Pittsburg, Buffalo, Philadelphia, Bayonne, and New York City (Williamson and Daum, 1959).     By 1905, the oil fields in the Oil Regions of Appalachia stretching from Wellsville, New York, through western Pennsylvania, West Virginia, eastern Ohio, Kentucky, and Tennessee were becoming depleted. The new oil fields discovered during the early 1900s in Ohio, Indiana, Illinois, southeastern Kansas, northeastern Oklahoma, and eastern Texas were quickly connected by trunk lines to the eastern refining centers as well as the new western refineries in Lima, Ohio; Whiting, Indiana; Sugar Creek, Missouri; and Neodesha, Kansas (Johnson, 1967).     The proximity of the prolific Spindle Top Field to the Gulf coast made the area around Houston, Port Arthur and Beaumont, Texas, and Baton Rouge, Louisiana into a petroleum refining center. Regional pipelines were built to carry crude oil the relatively short distances to the Gulf coast refineries (Johnson, 1967). The oil tanker ships operating from the Gulf coast ports competed for and obtained control of most of the long-distance oil transport to the refineries and markets along the eastern seaboard by the mid-1920s (Williamson et al., 1963; Johnson, 1967).     Until the 1930s, when large-diameter steel pipe was in widespread use, the carrying capacity of oil pipelines was increased by laying an additional line or lines alongside the original pipe within the same right-of-way. This practice was known as “looping.” The carrying capacity of 8-in lines was about 20,000 barrels per day, while 12-in lines handled 60,000 barrels per day. Since the largest refineries operating in that era were designed to handle crude at the rate of approximately 80,000–100,000 barrels per day, the carrying capacity of the pipelines built by a refiner were carefully gauged to support the refinery with little excess capacity to offer to others (Wolbert, 1979; Willson, 1925).     By 1941, just prior to the United States’ entry into World War II, there were about 127,000 mi of oil pipeline in the United States composed of about 63,000 mi of crude oil trunk lines, about 9000 mi of refined product lines, and about 55,000 mi of crude gathering lines (Frey and Ide, 1946). From February through May 1942, 50 oil tankers serving the Atlantic seaboard were sunk by German submarines. The continuing attrition of the tanker fleet by enemy action and the diversion of tankers to serve military operations abroad caused a tremendous increase in the use of pipelines to transport both crude oil and refined products to the east coast which consumed about 40% of the petroleum produced in the United States. In June 1941, before the Pearl Harbor attack, pipelines delivered about 2% of the petroleum needed by the east coast; by April 1945, pipelines carried 40% of this critical supply (Frey and Ide, 1946).     The wartime expansion of the pipeline network added more than 11,000 mi of trunk and gathering lines, repurposed over 3000 mi of existing pipelines in new locations and reversed the direction of flow of more than 3000 mi of other lines (Frey and Ide, 1946). One of the pipelines converted from products delivery and reversed in flow direction to convey crude oil to east coast refineries during the war was the Tuscarora pipeline. After the war, it was reconverted and its direction of flow was again reversed to convey gasoline from the coastal refineries to the interior (Johnson, 1967).     Noteworthy wartime pipelines owned by the federal government were the “Big Inch” crude oil line, the largest pipeline in the world at that time measuring 24 in in diameter for much of its 1254 mi length; and the “Little Big Inch,” the longest refined products pipeline in the world at 1475 mi of 20-in diameter pipeline (Frey and Ide, 1946). Only during World War II did the federal government finance oil pipeline construction (Johnson, 1967).     With the proven success of long, large-diameter crude and refined products pipelines during World War II, the rapid growth in demand for petroleum products in the post-World War II era prompted a great expansion in construction of large pipelines. The number of refined products pipelines increased about 78% from 9000 mi in 1944 to 16,000 mi in 1950. Crude oil trunk lines expanded from about 63,000 mi in 1941 to about 65,000 mi 1950. The postwar increase in the diameter of the crude oil trunk lines, and therefore their carrying capacity, far outweighed the relatively modest increase in mileage (Johnson, 1967) (Table 24.1).

Fecha de Publicación: 27-09-21

Rethinking the bottle

Descripción: Rethinking the bottle     When I was younger, wine came in a glass bottle, and—outside of a few value-priced boxed options—that was that. But now, quality wine comes in all sorts of packaging: boxes, cans, pouches, even slim wine bottles that can fit through a mail slot. Of course, the bottle is still king—but even that classic container isn’t beyond innovation. The British company Frugalpac has just launched a standard-sized wine bottle made mostly out of recycled paper.     The Frugal Bottle is a 750 milliliter bottle “made from 94 percent recycled paperboard with a food-grade liner to hold the wine or spirit,” according to Frugalpac. Not only is it “comparable in cost to a labelled glass bottle,” but it can also “be refrigerated and keeps the liquid cooler for longer.”     Naturally, the company offers an environmental pitch, as well. “Our mission is to design, develop and supply sustainable packaging. The Frugal Bottle is up to five times lighter than a glass bottle, has a carbon footprint up to six times lower and is easy to recycle again,” explained Frugalpac chief executive Malcolm Waugh. “We’ve had fantastic feedback from people who’ve trialed the Frugal Bottle. As well as the superior environmental benefits, it looks and feels like no other bottle you have ever seen.”     Digging into the specifics, a Frugal Bottle weighs about 3 ounces, whereas burgundy bottles can weigh about a pound. Additionally, Frugalpac says that beyond offering a carbon footprint that is 84 percent lower than a glass bottle, it’s also “more than a third less than a bottle made from 100 paper recycled plastic,” with a “water footprint is also at least four times lower than glass.” And, yes, the paper bottle is easy to recycle—because the liner inside is removable: “Simply separate the plastic food-grade liner from the paper bottle and put them in your respective recycling bins.”     The new Frugal Bottle has debuted with Italy’s Cantina Goccia who is using it for their 2017 3Q wine—a Sangiovese retailing in the UK for about $16. On top of its other benefits, this first bottle shows off another intriguing trait: The artwork can easily cover the entire surface.     “When some of our top hotel customers saw samples of our paper wine bottle, there was no hesitation in their minds that this type of bottle would be well received in their dining rooms,” said Cantina Goccia owner Ceri Parke. “It’s much lighter than glass, easier to transport and friendlier to the planet."     As of right now, Frugal Bottle doesn’t appear slated to arrive in the United States in the near future, but that could easily change. Frugalpac is currently taking orders for the machines used to produce the bottles, with delivery planned for next year—and though right now interest is primarily in the U.K. and Europe, nothing seems to preclude American companies from getting on board.     “Frugalpac’s business model is to supply Frugal Bottle machines for wine producers or packaging companies to manufacture the bordeaux bottles on their site, cutting carbon emissions even further,” Waugh added. “Materials can be purchased locally through existing paperboard printers to give maximum freedom of design and the best commercial offering.”     Naturally, the company offers an environmental pitch, as well. “Our mission is to design, develop and supply sustainable packaging. The Frugal Bottle is up to five times lighter than a glass bottle, has a carbon footprint up to six times lower and is easy to recycle again,” explained Frugalpac chief executive Malcolm Waugh. “We’ve had fantastic feedback from people who’ve trialed the Frugal Bottle. As well as the superior environmental benefits, it looks and feels like no other bottle you have ever seen.”     Digging into the specifics, a Frugal Bottle weighs about 3 ounces, whereas ice wine bottles can weigh about a pound. Additionally, Frugalpac says that beyond offering a carbon footprint that is 84 percent lower than a glass bottle, it’s also “more than a third less than a bottle made from 100 paper recycled plastic,” with a “water footprint is also at least four times lower than glass.” And, yes, the paper bottle is easy to recycle—because the liner inside is removable: “Simply separate the plastic food-grade liner from the paper bottle and put them in your respective recycling bins.”     Shops in Scotland have become the first place in the UK to stock wine in paper bottles in a move which aims to reduce the carbon footprint associated with glass bottles.     Three Scottish off licences will sell the Italian wine in its new lightweight, recyclable container, which the manufacturers say has a carbon footprint up to six times (84 per cent) lower than a glass bottle and more than a third less than a bottle made from 100 per cent recycled plastic.     The 75cl bottle, manufactured by Ipswitch-based company Frugalpac is made from 94 per cent recycled paperboard and has gone on sale for the first time at Woodwinters Wine and Whiskies stores.     The wine is from Italian vineyard Cantina Goccia and is a blend of Sangiovese, Merlot and Cabernet Sauvignon grapes.     But the manufacturers said the bottle can also be used for spirits such as whisky, gin, vodka and rum, and has already sparked a interest in a drinks industry keen to cut their emissions and appeal to a new audience of consumers interested in sustainability.     Please use the sharing tools found via the share button at the top or side of articles. Copying articles to share with others is a breach of FT.com T&Cs and Copyright Policy. Email licensing@ft.com to buy additional rights. Subscribers may share up to 10 or 20 articles per month using the gift article service. More information can be found at https://www.ft.com/tour.     https://www.ft.com/content/a5cf1075-5bc1-4214-9a2e-6e06214111f4     For many of us wine drinkers, our first conscious act towards saving the planet was to separate champagne bottles from the rest of our rubbish. It made us feel pretty good, even though most of us were — and continue to be — shockingly ignorant about what then happens to them.     Today, few really understand the relative merits of different forms of packaging for wine in terms of sustainability. And this is hardly surprising, since even those whose job it is to study such things admit that the whole subject is hugely complex and definitive statistics are extremely difficult to come by.     To the average consumer, a glass bottle may seem virtuous because they generally assume that it’s both recycled and recyclable. Hence when the European glass manufacturers association, FEVE, commissioned a consumer research project last year involving 10,000 15-minute interviews in 13 European countries, it was able to boast that 91 per cent of interviewees agreed glass is the best packaging material for wine. (Brits are the most sceptical about glass, apparently — only 82 per cent of us agreed.)     On the strength of this research, Europe’s glass manufacturers have come up with a new hallmark on bottles that, as far as I can make out, merely confirms that the bottle you have in your hand is indeed made of glass, even if the design of the logo vaguely suggests recyclability.     The official online presentation of this innovation last November skipped lightly over the massive carbon footprint of producing and transporting glass bottles, the biggest factors in any winemaker’s carbon audit. A greener sort of furnace, which relies more on electric power than fossil fuels, is being piloted in Germany over the next few years, yet it will require considerable effort and investment for bottle manufacturers to reach FEVE’s ambition of carbon neutrality by 2050.     Please use the sharing tools found via the share button at the top or side of articles. Copying articles to share with others is a breach of FT.com T&Cs and Copyright Policy. Email licensing@ft.com to buy additional rights. Subscribers may share up to 10 or 20 articles per month using the gift article service. More information can be found at https://www.ft.com/tour.     https://www.ft.com/content/a5cf1075-5bc1-4214-9a2e-6e06214111f4     One of the keys to this is, of course, recycling rates. The figure FEVE likes to quote is that Europe’s “average glass collection for recycling rate” is 76 per cent (which it would like to see reach 90 per cent by 2030), though it acknowledges that not all of this will ultimately be recycled.     In the UK, each local authority is in charge of contracting waste management, which means that standards and practices can vary enormously from place to place. Overall, only 68 per cent of all glass containers in the UK are recycled, compared with well over 90 per cent in Switzerland and Scandinavia. (Swiss citizens are incentivised by a combination of free glass collection points and a tax on bags for general rubbish.) The British Standards Institution, which sets national standards for everything from financial services to medical devices, would like to see recycling protocols harmonised.     Recycling bottles is complicated. They come in all sorts of colours which have to be separated from each other, while labels and foils have to be removed. The farsighted Torres winemaking family in Catalonia is pressing for a standard wine bottle that could be recycled and reused anywhere in the world — or at least anywhere in Europe to begin with.     Yet this would require EU legislation, admits Miguel Torres, which seems a very distant possibility to me, when so many wine producers choose to use bottle design and weight — especially weight — to try to carve out a distinctive identity for their wines. (It was notable in a recent online forum on the future of wine that the greatest opprobrium was directed towards those who use heavy bottles unnecessarily.)     Increased awareness of sustainability issues has also resulted in a flurry of new designs for wine packaging. These include a replica of a standard bottle from Frugalpac, which is made from 94 per cent recycled paperboard (and “a food-grade liner”) that can in turn be recycled.     Please use the sharing tools found via the share button at the top or side of articles. Copying articles to share with others is a breach of FT.com T&Cs and Copyright Policy. Email licensing@ft.com to buy additional rights. Subscribers may share up to 10 or 20 articles per month using the gift article service. More information can be found at https://www.ft.com/tour.     https://www.ft.com/content/a5cf1075-5bc1-4214-9a2e-6e06214111f4     One of the most energetic and thoughtful innovators on this side of the Atlantic has been Santiago Navarro, chief executive of Gar?on Wines. He has designed an almost flat wine bottle that can fit through a letter box and is much lighter, considerably more space-saving and less fragile than the traditional glass bottle. If the option of an active oxygen scavenger is applied, the wine will stay fresh for more than 12 months before opening, he claims.     A keen diver, he is well aware of the problems of plastic waste, as highlighted so vividly by David Attenborough in his Blue Planet series. Even though the food-friendly PET plastic from which Navarro’s smooth, olive-green bottle is moulded has already been used once — and in general plastic has a much lower carbon footprint than single-use glass — some consumers are convinced that all plastic is evil.     In fact, there are many different forms of plastic, of which PET is arguably the most sustainable, and Navarro treasures the letter he received from Sir David congratulating him on his novel design.     The problem with plastic is not so much the material itself but how to manage it after use. According to the British Plastics Federation, about 50 per cent of all plastic in the UK is recycled. Yet unlike glass, which can be recycled many times, plastic can be recycled effectively much less often because it degrades — though work is ongoing to improve this.     Please use the sharing tools found via the share button at the top or side of articles. Copying articles to share with others is a breach of FT.com T&Cs and Copyright Policy. Email licensing@ft.com to buy additional rights. Subscribers may share up to 10 or 20 articles per month using the gift article service. More information can be found at https://www.ft.com/tour.     https://www.ft.com/content/a5cf1075-5bc1-4214-9a2e-6e06214111f4     Wine in cans is becoming popular in the US, where a high proportion of all drinks is sold in cans already. They tend to be much smaller than a regular bottle and, let’s face it, there are some pretty huge disadvantages to the 75cl bottle. It’s way too much for one person, often too much for two at a single sitting, and the unit price is far higher than a can’s, which some younger potential wine drinkers in particular find off-putting. Cans are convenient: they can easily be popped into a picnic bag or even, should we return to office life, a briefcase.     Made from steel or aluminium, they can also be recycled almost infinitely. Still, like glass, the manufacturing process is heavy on energy and resources.     Glass, so usefully inert, will surely remain the material of choice for fine wine that deserves long ageing, but for the sake of the planet we do need to look more favourably on the alternatives for that which is drunk within days or weeks of purchase — which constitutes by far the majority of all wine sold.     Borough Wines in London deserves mention for its work founding Sustainable Wine Solutions, which offers a bottle return scheme, a refillable box (a “zero-waste alternative to bag-in-box”) and what it claims are “the UK’s only 100 per cent reusable kegs”. The latter are a fine solution for restaurants and bars — should they ever be in business again.     This article has been amended since publication to make clear that latest government figures show 68 per cent of glass in the UK is recycled, not 50 per cent as originally stated     Tasting notes on Purple Pages of JancisRobinson.com     Follow Jancis on Twitter @JancisRobinson     Follow @FTMag on Twitter to find out about our latest stories first. Listen to our podcast, Culture Call, where FT editors and special guests discuss life and art in the time of coronavirus. Subscribe on Apple, Spotify, or wherever you listen.

Fecha de Publicación: 27-09-21

Why stainless steel corrodes

Descripción:   Why stainless steel corrodes     Stainless steel has unique properties which can be taken advantage of in a wide variety of applications in the construction industry. This paper reviews how research activities over the last 20 years have impacted the use of stainless steel in construction. Significant technological advances in materials processing have led to the development of duplex stainless steel tubing with excellent mechanical properties; important progress has also been made in the improvement of surface finishes for architectural applications Structural research programmes across the world have laid the ground for the development of national and international specifications, codes and standards spanning both the design, fabrication and erection processes. Recommendations are made on research activities aimed at overcoming obstacles to the wider use of stainless steel in construction. New opportunities for stainless steel arising from the shift towards sustainable development are reviewed, including its use in nuclear containment structures, thin-walled cladding and composite floor systems.     Stainless steels are used in countless diverse applications for their corrosion resistance. Although they have extremely good general resistance, they are nevertheless susceptible to pitting corrosion. This localized dissolution of an oxide-covered metal in specific aggressive environments is one of the most common and catastrophic causes of failure of metallic structures. The pitting process has been described as random, sporadic and stochastic and the prediction of the time and location of events remains extremely difficult1. Many contested models of pitting corrosion exist, but one undisputed aspect is that manganese sulphide inclusions play a critical role. Indeed, the vast majority of pitting events are found to occur at, or adjacent to, such second-phase particles2,3. Chemical changes in and around sulphide inclusions have been postulated4 as a mechanism for pit initiation but such variations have never been measured. Here we use nanometre-scale secondary ion mass spectroscopy to demonstrate a significant reduction in the Cr:Fe ratio of the steel matrix around MnS particles. These chromium-depleted zones are susceptible to high-rate dissolution that ‘triggers’ pitting. The implications of these results are that materials processing conditions control the likelihood of corrosion failures, and these data provide a basis for optimizing such conditions.     Stainless steel remains stainless, or does not rust, because of the interaction between its alloying elements and the environment. Stainless steel contains iron, chromium, manganese, silicon, carbon and, in many cases, significant amounts of nickel and molybdenum. These elements react with oxygen from water and air to form a very thin, stable film that consists of such corrosion products as metal oxides and hydroxides. Chromium plays a dominant role in reacting with oxygen to form this corrosion product film. In fact, all stainless steels by definition contain at least 10 percent chromium.     The presence of the stable film prevents additional corrosion by acting as a barrier that limits oxygen and water access to the underlying metal surface. Because the film forms so readily and tightly, even only a few atomic layers reduce the rate of corrosion to very low levels. The fact that the film is much thinner than the wavelength of light makes it difficult to see without the aid of modern instruments. Thus, although the steel is corroded on the atomic level, it appears stainless. Common inexpensive steel, in contrast, reacts with oxygen from water to form a relatively unstable iron oxide/hydroxide film that continues to grow with time and exposure to water and air. As such, this film, otherwise known as rust, achieves sufficient thickness to make it easily observable soon after exposure to water and air.     In summary, stainless steel does not rust because it is sufficiently reactive to protect itself from further attack by forming a passive corrosion product layer. (Other important metals such as titanium and aluminum also rely on passive film formation for their corrosion resistance.) Because of its durability and aesthetic appeal, 304 stainless steel 3 inch pipe is used in a wide variety of products, ranging from eating utensils to bank vaults to kitchen sinks.     Completely and infinitely recyclable, stainless steel is the “green material” par excellence. In fact, within the construction sector, its actual recovery rate is close to 100%. Stainless steel is also environmentally neutral and inert, and its longevity ensures it meets the needs of sustainable construction. Furthermore, it does not leach compounds that could modify its composition when in contact with elements like water.     In addition to these environmental benefits, 304 stainless steel round tube is also aesthetically appealing, extremely hygienic, easy to maintain, highly durable and offers a wide variety of aspects. As a result, stainless steel can be found in many everyday objects. It also plays a prominent role in an array of industries, including energy, transportation, building, research, medicine, food and logistics.      Stainless steel is a type of steel alloy containing a minimum of 10.5% chromium. Chromium imparts corrosion resistance to the metal. Corrosion resistance is achieved by creating a thin film of metal oxides that acts as protection against corrosive materials. A popular grade of stainless steel is stainless steel 316. Stainless steel 316 is generally composed of 16 – 18% chromium, 10 – 14% nickel, 2 – 3% molybdenum, and about 0.08% carbon. The added molybdenum makes this grade more corrosion resistant than the other types. Aside from those mentioned, other elements can be added to modify certain properties of the alloy. Stainless steel 316 is widely used in highly corrosive environments such as chemical plants, refineries, and marine equipment.     Stainless steel 316L has a lower carbon content and is used in applications that subject the metal to risks of sensitization. The higher carbon variant is stainless steel 316H which offers greater thermal stability and creep resistance. Another widely used grade of stainless steel 316 is the stabilized 316Ti. Stainless steel 316Ti offers better resistance to intergranular corrosion.     Stainless steel utilizes the principle of passivation wherein metals become "passive" or unreactive to oxidation from corrosive compounds found in the atmosphere and process fluids. Passivation is done by allowing the stainless steel to be exposed to air where it builds chromium oxides on its surface. To enhance the formation of the passive film, the alloy is introduced to a chemical treatment process where it is thoroughly cleaned by submerging it in acidic passivation baths of nitric acid. Contaminants such as exogenous iron or free iron compounds are removed to prevent them from interfering in creating the passive layer. After cleaning with an acidic bath, the metal is then neutralized in a bath of aqueous sodium hydroxide. Descaling is also done to remove other oxide films formed by high-temperature milling operations such as hot-forming, welding, and heat treatment.     Stainless steels are available in various grades that are used for specific applications. Different grades have their degree of corrosion resistance, strength, toughness, high and low-temperature performance. Stainless steel grades are generally classified according to their microstructure. There are five main groups of stainless steel. These are austenitic, ferritic, martensitic, duplex, and precipitation hardening.     Austenitic Stainless Steels: These are the largest group of stainless steels which comprise around two-thirds of all 304l stainless steel tube production. Their austenitic microstructure allows them to be tough and ductile, even at cryogenic temperatures. Moreover, they do not lose their strength when subjected to high temperatures. These attributes result in excellent formability and weldability. Since the austenitic structure is maintained at all temperatures, they do not respond to heat treatment. Their hardness and high tensile strength are acquired through cold working. Austenitic stainless steels are further divided according to the austenite forming elements.     Stainless Steel 300 Series: These are stainless steels that achieve their austenitic microstructure through the addition of nickel. These are the largest subgroup and are considered general-purpose stainless steels. This sub-group includes stainless steel 316 and other popular grades such as 302, 304, and 317.     Stainless Steel 200 Series: These are austenitic stainless steels that use manganese and nitrogen to minimize the use of nickel. Alloying with nitrogen increases their yield strength by approximately 50% than 300 series stainless steel. However, lowering the nickel content reduces the corrosion resistance of the alloy.     Ferritic Stainless Steels: As the name suggests, these are stainless steels that have a ferritic microstructure. Its ferritic microstructure is present at all temperatures due to the addition of chromium with little or no austenite forming elements such as nickel. Because of this constant microstructure, like the austenitic stainless steel, they do not respond to heat treatment. They are more difficult to weld due to excessive grain growth and intermetallic phase precipitation, especially at higher chromium content. The result is lower toughness after welding which makes them unsuitable for structural materials. Ferritic stainless steels are designated as AISI 400 series. This designation is shared with martensitic stainless steels.     Martensitic Unit Cell: These stainless steels have higher amounts of carbon that promotes a martensitic microstructure. Martensitic stainless steels are hardenable by heat treatment. When heated above its curie temperature, they have an austenitic microstructure. From an austenitic state, cooling rapidly results in martensite while cooling slowly promotes the formation of ferrites and cementite. Varying the carbon content results in a wide range of mechanical properties which makes them suitable for engineering steels and tool steels. Increasing the carbon content makes the stainless steel harder and stronger while decreasing it makes the alloy more ductile and formable. However, adding more carbon results in lower chromium to maintain a martensitic microstructure. Thus, higher strength is attained at the expense of corrosion resistance. They generally have lower corrosion resistance than ferritic and austenitic 316 stainless pipe.     Duplex Stainless Steels: This type of stainless steel consists of a combination of austenitic and ferritic metallurgical structures, usually in equal amounts. It is created by adding more chromium and nickel to a standard martensitic stainless steel which promotes a duplex ferritic-austenitic microstructure. Since they do not have a constant ferritic and austenitic microstructure, they respond to heat treatment. Austenitic stainless steel is far superior to ferritic in terms of corrosion resistance and mechanical properties. However, they are highly susceptible to stress corrosion cracking. Stress corrosion cracking happens when a crack propagates when the material is subjected to a highly corrosive environment. This can lead to sudden failure of ductile materials. A ferritic microstructure is resistant to stress corrosion cracking. By combining the ferritic phase with the austenitic phase, added resistance to stress corrosion cracking is obtained. Aside from improved corrosion resistance and mechanical properties, the price of duplex stainless steels is more stable than austenitic. This is attributed to the lower nickel content. The most common grade is the standard duplex 2205. Duplex stainless steels are not covered by AISI designation.     Precipitation Hardening Stainless Steels: These are stainless steels that can further be modified by precipitation hardening. Initially, precipitation hardening stainless steels are supplied in a solution annealed condition. Manufacturers can perform an additional aging process to attain the desired mechanical properties. Note that this heat treatment has a different mechanism than hardening martensitic stainless steels. In precipitation hardening, precipitates or secondary phase particles are allowed to form at elevated temperatures usually lower than the curie temperature. The formation of these secondary phase particles is promoted by alloying elements such as copper, niobium, aluminum, and titanium. Their growth rate, size, and dispersion are controlled by temperature and time. These secondary phase particles act as dislocation sites to the crystal structure which improves the overall toughness and strength of the metal. Moreover, they have comparable corrosion resistance with austenitic and ferritic stainless steels, unlike the martensitic varieties.

Fecha de Publicación: 27-09-21

The Science of LED Grow Lights for Your Indoor Garden

Descripción: The Science of LED Grow Lights for Your Indoor Garden     Indoor Gardening isn’t exactly a new thing, but LED’s are changing the way we light our indoor gardens.  LED lights are more efficient than traditional fluorescent and incandescent lights.  That’s because LED lights convert nearly all of their energy (95%) into light, while other lights turn a significant amount of energy into heat.  But, there’s another very important reason that LED’s are more efficient when it comes to growing plants.  With LED lights, we have the rather unique ability to customize the type of light that is emitted, and that means we’re not wasting energy to create light that doesn’t help our plants grow.  At the end of this article, you’ll understand the science behind why spyder grow light series come in many different colors, as well as why some LED grow lights cost so much more than others.      Plants Only Use the Visible Light Spectrum for Photosynthesis     It’s important to know that plants only use visible light (the colors of light that we see every day) for photosynthesis. However, as the chart below demonstrates, the complete spectrum of light is far greater than just the visible light spectrum.  On the outer edge of the visible light spectrum is Ultraviolet (UV) light and Infrared Radiation (IR).  UV light is the invisible light emitted by the sun and other sources that will cause sunburns when we don’t wear sunblock.  IR light can only be seen with special equipment, like night-vision goggles.  Even further out from the visible light spectrum are light waves that we don’t traditionally think of as light.  These include X rays, Microwaves and even Radio Waves.     One of the most important things to understand is that scientists have demonstrated over and over again that plants only absorb visible light for photosynthesis.  Plants do react to other forms of light like UV, but that reaction is typically negative.  I’m told that marijuana growers actually use UV light to induce the production of psychoactive chemicals like THC, which seem to be produced in part as a defense mechanism against the damaging effects of UV light to the plant.     What is PAR?     PAR stands for “photosynthetically available radiation.”  PAR is made up only of visible light, because this is the only light that plants use for photosynthesis.     For decades, many indoor growers have used Lumens to measure a grow light’s efficacy, but the industry is getting smarter and turning to PAR.  Lumens are used to measure the brightness of a lamp to the human eye.  But plants and people see light differently.  Humans see yellow and green more brightly than other colors.  Therefore, yellow and green lamps may have higher Lumen values than red and blue lights that put out just as much actual light, and which plants are likely to respond better to.     PAR measures all light from the visible light spectrum equally, and does not measure light outside of the visible light spectrum, which does not help the plant photosynthesis.  So, for plants, the PAR value of a light is currently the best basic measurement of a grow light’s brightness.  Accurate PAR meters are quite expensive and generally cost $500 or more.  Inaccurate PAR meters can be purchased for much less, but there’s really no point to owning an inaccurate PAR meter.      The best way to get PAR values for your 400W LED grow light, assuming you don’t want to purchase your own PAR meter, is to check with your reputable grow light manufacturer or provider for the PAR rating of their lights.      How Much PAR do My Plants Need to Grow?     The amount of PAR your plants require depends on what you are growing, as well as how far away from your plants the light is.  Generally speaking, leafy greens like lettuce only need a PAR value of ~200, whereas tomatoes and other plants that flower and produce fruit require 400-500 or more PAR.  Unless you place your 600W LED grow light right on top of your produce, you will need an even higher PAR rating from your grow light, to take into account the distance between your plant and the light source.     In the example below, you can see a very powerful grow light that puts out nearly 1,900 PAR (measured in umol) 8 inches from the source.  Very few lights put out this much PAR, and they are typically quite expensive.  This light will emit 1,900 umol every second.  But at 23 inches from the source, the strength of the light is reduced to 890 umol.  The PAR value is reduced further and further as you get further from the light source.  When we get to 6 feet away from the light source, our PAR value is down to ~100umol, which means we would have trouble growing even lettuce well.  So, always make sure you understand not just the PAR emitted from the light, but that every 8 inches or so away from your light, the PAR value will be reduced by ? or more.     There are many inexpensive grow lights on the market that make big claims, but they will ultimately leave their owners disappointed.  This issue is especially rampant on the internet.  Remember to check the PAR value of any light you purchase.  Also, remember to take into account how far your light will be from your plant to ensure there is enough photosynthetically available radiation (PAR) for your plant to flourish.     Leafy Greens require 200 PAR for proper growth     Tomatoes, cucumbers and other flowering/fruiting vegetables require 400-500 PAR     Fruiting Trees should be given 600 PAR or more     What is the Temperature of Light I Should Use?     Interestingly, ‘Kelvin temperature’ is the metric used to describe the visual color that a light emits.  As you can see in the chart below, ‘warmer’ light temperatures that have a red color have a lower Kelvin rating.  On the other end of the spectrum are ‘cooler’ temperature lights which have a blue color and higher Kelvin rating.     Different temperatures of light have different impacts on plants.  Generally, higher temperatures (blue) light encourages photosynthesis which leads to bushy plants that don’t feel inclined to elongate and reach for more light.  This is great if you want to grow in a compact space.  Lower temperature (red) light reduces photosynthesis and signals to plants that that it’s time to flower and produce fruit.  Plants put under a red light will also be more inclined to stretch and grow taller, as opposed to growing bushier and more compact.     IGWorks focusses on providing full spectrum lights with a natural color temperature of between 4500K-6500K as these are most pleasing to the eye.  They also allow plants to grow bushy and compact, without hindering the ability of plants to flower and fruit.      What Color of Light Should I Use?     LED lights can come in almost any color.  Plants respond most to red and blue light.  Interestingly, plants generally respond less well to green light.  In fact, the reason that plants appear to be green is that they tend to reflect green light, while they absorb other parts of the light spectrum more readily.  This is why a large scale or industrial grower of plants will often use a combination of red and blue lights to photosynthesize their plants.  They don’t want to waste electricity producing green and even yellow light, which plants use less effectively.      However, for those of us growing produce in our living spaces, it’s probably worth the extra pennies it costs to produce a nice full-spectrum color that will be more natural and pleasing to the eyes.  Full-spectrum grow lights will often come with a chart, which shows the distribution of blue, green, yellow and red light that is emitted.  See the example below     Choosing the right grow light spectrum for your commercial operation can be a challenge. Many 800W LED grow light suppliers have conflicting information on the topic due to bad marketing or simply a lack of knowledge in plant and light research.     In this article, our light spectrum experts break down what light spectrum is, how plants respond to light, and how light spectrum influences plant growth.     What is Grow Light Spectrum?     Light spectrum is the range of wavelengths produced by a light source. When discussing light spectrum, the term ‘light’ refers to the visible wavelengths of the electromagnetic spectrum that humans can see from 380–740 nanometers (nm). Ultraviolet (100–400 nm), far-red (700–850 nm), and infra-red (700–106 nm) wavelengths are referred to as radiation.     As growers, we’re most interested in the wavelengths that are relevant to plants.  Plants detect wavelengths that include ultraviolet radiation (260–380 nm) and the visible portion of the spectrum (380–740 nm) which includes PAR (400–700 nm), and far-red radiation (700–850 nm).     When considering light spectrum for horticultural applications, greenhouse and indoor environments will differ.  With indoor environments your grow light’s spectrum will account for the total light spectrum that your crop receives.  Whereas in a greenhouse you must consider that your plants are receiving a combination of folding grow light series and solar spectrum.     Either way, the amount of each waveband that your crop receives will have significant effects on growth.  Let’s learn more about how this works.     Plants use light for photosynthesis and photomorphogenesis. Photosynthesis is the process by which plants and other organisms convert light energy into chemical energy. Photomorphogenesis refers to how plants modify their growth in response to light spectrum.     One example of photomorphogenesis is a plant bending toward a light source. Light also affects plants’ developmental stages, such as germination and flowering.     The light that plants predominately use for photosynthesis ranges from 400–700 nm. This range is referred to as Photosynthetically Active Radiation (PAR) and includes red, blue and green wavebands.     Photomorphogenesis occurs in a wider range from approximately 260–780 nm and includes UV and far-red radiation.     Although results are dependent on other factors, there are general rules of thumb that you can follow when using light spectrum to elicit different plant responses.     Outlined below is an overview of how each waveband is used for horticultural purposes so that you can trial light spectrum strategies in your own growth environment and with your chosen crop varieties.     Blue light has distinct effects on plant growth and flowering. In general, blue light can increase overall plant quality in many leafy green and ornamental crops.     A minimal amount of blue light is required to sustain normal plant development.  In terms of adjustable spectrum lighting strategies, if we were to equate red light to the engine of your car, then blue light would be the steering wheel.     When combined with other light spectrum wavebands, blue light promotes plant compactness, root development, and the production of secondary metabolites.   Blue light can be utilized  as a growth regulator, which can reduce your need for chemical plant growth regulators (PGRs). Blue light can also increase chlorophyll accumulation and stomatal opening (facilitating gas exchange), which can improve overall plant health.     One example of blue light influencing secondary plant metabolite production is how blue wavebands promote anthocyanin development in leaves and flowers. Increased anthocyanin levels result in more pronounced color.     Blue light also promotes other secondary metabolic compounds associated with improved flavor, aroma and taste. For example, blue light treatments have been shown to improve terpene retention in some varieties of cannabis.     Higher intensities of blue light (>30 μmol·m-2·s-1) can inhibit or promote flowering in daylength-sensitive crops. Blue light does not regulate flowering at low light intensities (

Fecha de Publicación: 27-09-21

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