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The air conditioning trap: how cold air is heating the world

Descripción:     The air conditioning trap: how cold air is heating the world     On a sweltering Thursday evening in Manhattan last month, people across New York City were preparing for what meteorologists predicted would be the hottest weekend of the year. Over the past two decades, every record for peak electricity use in the city has occurred during a heatwave, as millions of people turn on their air conditioning units at the same time. And so, at the midtown headquarters of Con Edison, the company that supplies more than 10 million people in the New York area with electricity, employees were busy turning a conference room on the 19th floor into an emergency command centre.     Inside the conference room, close to 80 engineers and company executives, joined by representatives of the city’s emergency management department, monitored the status of the city power grid, directed ground crews and watched a set of dials displaying each borough’s electricity use tick upward. “It’s like the bridge in Star Trek in there,” Anthony Suozzo, a former senior system operator with the company, told me. “You’ve got all hands on deck, they’re telling Scotty to fix things, the system is running at max capacity.”     Power grids are measured by the amount of electricity that can pass through them at any one time. Con Edison’s grid, with 62 power substations and more than 130,000 miles of power lines and cables across New York City and Westchester County, can deliver 13,400MW every second. This is roughly equivalent to 18m horsepower.     On a regular day, New York City demands around 10,000MW every second; during a heatwave, that figure can exceed 13,000MW. “Do the math, whatever that gap is, is the AC,” Michael Clendenin, a company spokesman, told me. The combination of high demand and extreme temperature can cause parts of the system to overheat and fail, leading to blackouts. In 2006, equipment failure left 175,000 people in Queens without power for a week, during a heatwave that killed 40 people.     This year, by the evening of Sunday 21 July, with temperatures above 36C (97F) and demand at more than 12,000MW every second, Con Edison cut power to 50,000 customers in Brooklyn and Queens for 24 hours, afraid that parts of the nearby grid were close to collapse, which could have left hundreds of thousands of people without power for days. The state had to send in police to help residents, and Con Edison crews dispensed dry ice for people to cool their homes.     As the world gets hotter, scenes like these will become increasingly common. Buying a VRF air conditioner is perhaps the most popular individual response to climate change, and air conditioners are almost uniquely power-hungry appliances: a small unit cooling a single room, on average, consumes more power than running four fridges, while a central unit cooling an average house uses more power than 15. “Last year in Beijing, during a heatwave, 50% of the power capacity was going to air conditioning,” says John Dulac, an analyst at the International Energy Agency (IEA). “These are ‘oh shit’ moments.”     There are just over 1bn single-room air conditioning units in the world right now – about one for every seven people on earth. Numerous reports have projected that by 2050 there are likely to be more than 4.5bn, making them as ubiquitous as the mobile phone is today. The US already uses as much electricity for air conditioning each year as the UK uses in total. The IEA projects that as the rest of the world reaches similar levels, air conditioning will use about 13% of all electricity worldwide, and produce 2bn tonnes of CO2 a year – about the same amount as India, the world’s third-largest emitter, produces today.     All of these reports note the awful irony of this feedback loop: warmer temperatures lead to more air conditioning; more air conditioning leads to warmer temperatures. The problem posed by air conditioning resembles, in miniature, the problem we face in tackling the climate crisis. The solutions that we reach for most easily only bind us closer to the original problem.     The global dominance of air conditioning was not inevitable. As recently as 1990, there were only about 400m air conditioning units in the world, mostly in the US. Originally built for industrial use, air conditioning eventually came to be seen as essential, a symbol of modernity and comfort. Then air conditioning went global. Today, as with other drivers of the climate crisis, we race to find solutions – and puzzle over how we ended up so closely tied to a technology that turns out to be drowning us.     Like the aqueduct or the automobile, air conditioning is a technology that transformed the world. Lee Kuan Yew, the first prime minister of independent Singapore, called it “one of the signal inventions of history” that allowed the rapid modernisation of his tropical country. In 1998, the American academic Richard Nathan told the New York Times that, along with the “civil rights revolution”, air conditioning had been the biggest factor in changing American demography and politics over the previous three decades, enabling extensive residential development in the very hot, and very conservative, American south.     A century ago, few would have predicted this. For the first 50 years of its existence, air conditioning was mainly restricted to factories and a handful of public spaces. The initial invention is credited to Willis Carrier, an American engineer at a heating and ventilation company, who was tasked in 1902 with reducing humidity in a Brooklyn printing factory. Today we assume that the purpose of air conditioning is to reduce heat, but engineers at the time weren’t solely concerned with temperature. They wanted to create the most stable possible conditions for industrial production – and in a print factory, humidity curled sheets of paper and smudged ink.     Carrier realised that removing heat from the factory air would reduce humidity, and so he borrowed technology from the nascent refrigeration industry to create what was, and still is, essentially a jacked-up fridge. Then as now, air conditioning units work by breathing in warm air, passing it across a cold surface, and exhaling cool, dry air. The invention was an immediate success with industry – textile, ammunition, and pharmaceutical factories were among the first adopters – and then began to catch on elsewhere. The House of Representatives installed air conditioning in 1928, followed by the White House and the Senate in 1929. But during this period, most Americans encountered air conditioning only in places such as theatres or department stores, where it was seen as a delightful novelty.     It wasn’t until the late 1940s, when it began to enter people’s homes, that the TICA air conditioner really conquered the US. Before then, according to the historian Gail Cooper, the industry had struggled to convince the public that air conditioning was a necessity, rather than a luxury. In her definitive account of the early days of the industry, Air-Conditioning America, Cooper notes that magazines described air conditioning as a flop with consumers. Fortune called it “a prime public disappointment of the 1930s”. By 1938 only one out of every 400 American homes had an air conditioner; today it is closer to nine out of 10.     What fuelled the rise of the air conditioning was not a sudden explosion in consumer demand, but the influence of the industries behind the great postwar housing boom. Between 1946 and 1965, 31m new homes were constructed in the US, and for the people building those houses, air conditioning was a godsend. Architects and construction companies no longer had to worry much about differences in climate – they could sell the same style of home just as easily in New Mexico as in Delaware. The prevailing mentality was that just about any problems caused by hot climates, cheap building materials, shoddy design or poor city planning could be overcome, as the American Institute of Architects wrote in 1973, “by the brute application of more air conditioning”. As Cooper writes, “Architects, builders and bankers accepted air conditioning first, and consumers were faced with a fait accompli that they merely had to ratify.”     Equally essential to the rise of the dunham bush air conditioner were electric utilities – the companies that operate power plants and sell electricity to consumers. Electric utilities benefit from every new house hooked up to their grid, but throughout the early 20th century they were also looking for ways to get these new customers to use even more electricity in their homes. This process was known as “load building”, after the industry term (load) for the amount of electricity used at any one time. “The cost of electricity was low, which was fine by the utilities. They simply increased demand, and encouraged customers to use more electricity so they could keep expanding and building new power plants,” says Richard Hirsh, a historian of technology at Virginia Tech.     The utilities quickly recognised that air conditioning was a serious load builder. As early as 1935, Commonwealth Edison, the precursor to the modern Con Edison, noted in its end-of-year report that the power demand from terminal air conditioner was growing at 50% a year, and “offered substantial potential for the future”. That same year, Electric Light & Power, an industry trade magazine, reported that utilities in big cities “are now pushing air conditioning. For their own good, all power companies should be very active in this field.”     By the 1950s, that future had arrived. Electric utilities ran print, radio and film adverts promoting air conditioning, as well as offering financing and discount rates to construction companies that installed it. In 1957, Commonwealth Edison reported that for the first time, peak electricity usage had occurred not in the winter, when households were turning up their heating, but during summer, when people were turning on their air-conditioning units. By 1970, 35% of American houses had air conditioning, more than 200 times the number just three decades earlier.     At the same time, air-conditioning-hungry commercial buildings were springing up across the US. The all-glass skyscraper, a building style that, because of its poor reflective properties and lack of ventilation, often requires more than half its electricity output be reserved for air conditioning, became an American mainstay. Between 1950 and 1970 the average electricity used per square foot in commercial buildings more than doubled. New York’s World Trade Center, completed in 1974, had what was then the world’s largest AC unit, with nine enormous engines and more than 270km of piping for cooling and heating. Commentators at the time noted that it used the same amount of electricity each day as the nearby city of Schenectady, population 80,000.     The air-conditioning industry, construction companies and electric utilities were all riding the great wave of postwar American capitalism. In their pursuit of profit, they ensured that the light commercial air conditioner became an essential element of American life. “Our children are raised in an air-conditioned culture,” an AC company executive told Time magazine in 1968. “You can’t really expect them to live in a home that isn’t air conditioned.” Over time, the public found they liked air conditioning, and its use continued to climb, reaching 87% of US households by 2009.    

Fecha de Publicación: 09-10-21

Why is fiberglass mesh needed?

Descripción: Why is fiberglass mesh needed? Composite sheets of fiberglass mesh for marble reinforced polycarbonate were prepared by hot compress molding. The effects of lay-up structure, lay-up angle, area density of fiberglass mesh and the thickness of PC film on tensile property were studied. The results reveal that the alternative lay-up structure of reinforcement mesh and matrix film is optimal and tensile property declines as lay-up angle increases. Fiberglass mesh with lower area density is appropriate for thinner composites. Composite sheets fabricated with thinner PC film show better tensile property. SEM analysis shows that alternative lay-up structure is favorable to the immersion of the fiber bundle of marble mesh cloth with low area density in the melting matrix, and thus the improvement of tensile property. This paper investigates the effect of surface treatment for glass fiber, stainless steel wire mesh on tensile, flexural, inter-laminar shear and impact properties of glass fiber/stainless steel wire mesh reinforced epoxy hybrid composites. The glass fiber fabric is surface treated either by 1 N solution of sulfuric acid or 1 N solution of sodium hydroxide. The stainless steel wire mesh is also surface treated by either electro dissolution or sand blasting. The hybrid composites are fabricated using epoxy resin reinforced with glass fiber and fine stainless steel wire mesh by hand lay-up technique at room temperature. The hybrid composite consisting of acid treated glass fiber and sand blasted stainless steel wire mesh exhibits a good combination of tensile, flexural, inter-laminar shear and impact behavior in comparison with the composites made without any surface treatment. The fine morphological modifications made on the surface of the glass fiber and stainless steel wire mesh enhances the bonding between the resin and reinforcement which inturn improved the tensile, flexural, inter- laminar shear and impact properties. The fiberglass mesh filter is an inorganic non-metallic material with excellent performance. It has a wide variety of advantages. The advantages are good insulation, strong heat resistance, good corrosion resistance, and high mechanical strength, but its disadvantages are brittleness and poor wear resistance. It is made of glass balls or waste glass as raw materials through high-temperature melting, drawing, winding, weaving, and other processes. In this article, we will take a closer look at the characteristics and types of fiberglass mesh filters.  Characteristics of Fiberglass Mesh Filters The filter has high tensile strength and low elongation (3%). The filter has a high elastic coefficient and good rigidity. The filter has large elongation within the elastic limit and high tensile strength, so it can absorb impact energy. The filter is made of inorganic fiber, which is non-flammable and has good chemical resistance. Its water absorption is small. High-temperature resistance. High filtration efficiency. Types of Fiberglass Mesh Filters ULPA（Ultra Low Penetration Air) Filter ULPA (Ultra Low Penetration Air) filter has a filtration efficiency of more than 99.999% for 0.1~0.2μm particles, smoke and microbes, and other dust particles.  ULPA filter characteristics: Its filter element is made of ultra-fine glass fiber filter material by gluing and folding. The outer frame can be made of laminated wood, galvanized copper, stainless steel, and aluminum alloy, and it is tightly bonded by polyurethane glue. It has the characteristics of lightweight, large air permeability, dust collection rate as high as 99.95-99.999%, and alkali resistance, and high-temperature resistance. ULPA filter applications: It is suitable for class 10000-100 clean systems, air conditioning systems, so the product has been widely used in electronics, microelectronics, semiconductors, optical devices, biological and medical circuits, cameras, and optical instruments, precision machinery, and other fields. High-Temperature Air Filter The high-temperature air filter still has a partition structure. It is assembled with high-temperature resistant glass fiber or ultra-fine glass fiber filter paper, aluminum foil partition, stainless steel frame, and special high-temperature resistant sealant.  High-temperature air filters are mainly used in ultra-clean ovens that require drying in the production process of food, pharmaceuticals, etc., or high-temperature air purification equipment and systems. The maximum working temperature is 350 degrees. High Humidity Resistant Air Filter The high-humidity air filter has a partition structure, using special moisture-proof ultra-fine glass fiber filter paper, special rubber sheet or aluminum foil partition, galvanized sheet, or aluminum alloy profile frame. It is suitable for high humidity under normal temperature and pressure, especially in high humidity environments such as infusion production in the pharmaceutical industry. The maximum working humidity is 100%. The Disadvantage of Fiberglass Mesh Filters Due to the poor ductility of glass fiber, the glass fiber filter is easily damaged, so be careful when installing it. Conclusion  Thank you for reading our article and we hope it can help you to have a better understanding of the characteristics and types of marble fiberglass cloth. If you want to learn more about fiberglass mesh filters, we would like to advise you to visit Stanford Advanced Materials (SAM) for more information.  As a leading supplier of fiberglass mesh filters across the world, SAM enjoys over two decades of experience in the manufacture and sale of fiberglass mesh filters, offering customers high-quality fiberglass mesh filters to meet their R&D and production needs. As such, we are confident that SAM will be your favorite fiberglass mesh filter supplier and business partner. Fiberglass mesh is a neatly woven, crisscross pattern of fiberglass thread that is used to create new products such as tape and filters. When it is used as a filter, it is not uncommon for the manufacturer to spray a PVC coating to make it stronger and last longer. The most common place to find fiberglass mesh is in tape products. Sheetrock finishers use the mesh frequently. In fact, it is common to replace the paper tape used to float the joint between two pieces of sheetrock. The mesh that sheetrock finishers use comes on a roll just like paper sheetrock tape. The added benefit for the sheetrock finisher is to roll out the mesh over a great distance before having to apply the first coat of joint compound. Not only does it help them in this manner, but it also causes a stronger bond between the joint compound, the tape and the wall. Sheetrock finisher's also use this tape to patch holes. The most common hole in the sheetrock generally occurs where a doorknob has hit a wall too many times. If it is only slightly damaged, a couple of short pieces of the tape will be formed into a square and placed over the hole. A joint compound will then be applied directly to it. If the hole is too large to patch with fibreglass mesh for wall alone, a piece of metal flashing can be added behind the tape before applying joint compound. Construction work is not the only use for fiberglass mesh. As a filtering system, fiberglass mesh works really well. As the water flows through it, the mesh catches even the smallest impurities. In addition to this use, it can also be used as a mosquito net. Finally, fiberglass mesh is sometimes woven into protective clothing used by those who work with dangerous chemicals or firefighters. Tightly woven mesh is put together and shaped into jackets that firemen wear when they are battling a blaze. It protects them from any fire that might ignite their clothing while fighting a fire. Fiberglass mesh can also be used in mold making and as protection against corrosives. In your letter dated January 31, 2008, on behalf of your client, SpiderLath, Inc., you requested a tariff classification ruling on a woven fiberglass article. A sample of a piece of the material comprising this product was submitted with your ruling request.    The subject article, identified as "SpiderLath", is a woven fiberglass mesh/fiberglass lath system with ethylene vinylacetate (EVA) backing strips that will be imported in rolls 4 feet wide by 75 feet long. You indicated in a telephone conversation that the fiberglass mesh is coated with a stiffener. According to the information that was submitted with your ruling, the fiberglass mesh/fiberglass lath system is used as a cladding masonry support. The product can be used to install stucco and stone veneer. It can also be used over existing surfaces to apply masonry finishes. In your presentation, you suggest classification under subheading 7019.31.0000, Harmonized Tariff Schedule of the United States (HTSUS), which provides for glass fibers (including glass wool) and articles thereof...thin sheets (voiles), webs, mats, mattresses, boards and similar nonwoven articles: mats. This subheading does not apply since the product is a woven article. The applicable subheading for the woven fiberglass mesh for construction/fiberglass lath system with EVA backing strips will be 7019.90.1000, HTSUS, which provides for glass fibers (including glass wool) and articles thereof (for example, yarn, woven fabrics (con.): other: woven. The rate of duty will be 4.8 percent ad valorem. Duty rates are provided for your convenience and are subject to change. The text of the most recent HTSUS and the accompanying duty rates are provided on World Wide Web at http://www.usitc.gov/tata/hts/. This ruling is being issued under the provisions of Part 177 of the Customs Regulations (19 C.F.R. 177). A copy of the ruling or the control number indicated above should be provided with the entry documents filed at the time this merchandise is imported. If you have any questions regarding the ruling, contact National Import Specialist Jacob Bunin at 646-733-3027.

Fecha de Publicación: 09-10-21

What is a rod seal?

Descripción: What is a rod seal? There are so many different types of seals out there that it might be hard to understand all the different terminologies and functions. In this article, we give you our guide to what rod seals are, how they are manufactured and why you should choose rod seals from Martin's Rubber. Rod seals are often the decisive factor in ensuring that a hydraulic cylinder operates at peak performance. Leakage through the rod seal can lead to environmental damage and accidents, which is why it's crucially important to select the correct seal for your application. While leakage past a piston seal will affect its efficiency, the system fluid or gas remains contained in the system. With a rod seal, failure will allow external leakage, and it should be paired with an appropriate wiper and gland housing design to ensure correct operation. How do rod seals work? Rod seals perform the difficult balancing act of creating a seal at both high and low pressure. This is often in combination with alternating high and low temperatures. As such, they need to leave an oil film, thin enough to return into the cylinder, after having passed an effective wiper seal. When selecting a piston rod seals, it is important to define your area of application and provide carefully defined specifications. Martin's Rubber can then give you our recommendations for an appropriate rod seal to match your specific operating conditions. How are rod seals manufactured? Our rod seals can be CNC machined to bespoke sizes, including making adjustments away from original seal sizes to compensate for worn rod or gland conditions. Plus, we can help to restore the original performance of used equipment, as well as provide components for new build designs. Our standard rod seals can be rapidly manufactured in a variety of different materials, depending on your application. We also stock standard products for immediate shipment if your requirements are particularly time critical. Why choose our rod seals? "What sets us apart, I think, is that we're flexible," says Adam Hooper, Operations Director at Martin's Rubber. "We deliver the quality that people need in the most responsive way possible, and we add value in terms of engineering and creative input," he adds. Contact one of our expert advisers today on 023 8022 6330 or email sales@martins-rubber.co.uk to discuss your rod seal requirements. Designers often specify buffer seals be placed in front of primary rod seals in heavy-duty hydraulic applications to extend the life of the seals. As the name indicates, buffer seals "absorb" pressure spikes typical on heavy-duty cylinders to protect the primary rod seals. But how do these two types of seals interactions interact, which parameters affect those interactions, and how can they be used to extend the life of cylinder rod-sealing systems? What was learned during these investigations will give engineers insights into seal types and interactions between seals so they can specify the most appropriate seals for their applications. The key element of the buffer seal is the lubrication film thickness which passes the sealing edge. It is responsible for the performance of the entire rod sealing system. Different pressure and speed conditions during the in- and outstroke of the piston rod are typical for heavy-duty hydraulic cylinders and result in different oil film thickness. Therefore, the buffer seal needs to be designed to ensure a hydraulic cylinder rod step seals and absorb pressure peaks during operation. Generally, buffer seals use one of two basic design principles: High sealability buffer seals have good sealing abilities and can handle all of the system pressure and possible pressure peaks. Therefore, the primary rod seal will not be pressurized and can't be damaged by pressurization. The seal's high sealability means only a thin film of lubrication film can pass it, which could cause starve the primary rod seal of lubrication. This can lead to stick-slip, higher friction and sealing-edge temperatures, and possibly damage to the sealing material, all of which shorten the rod seal's life. Friction optimized buffer seals let thicker oil film pass the sealing edge to properly lubricate the primary rod seal. Depending on operating conditions, they can also let pressure build-up between the primary rod and buffer seals (intermediate pressure). These buffer seals should keep out system pressure, because if the intermediate pressure is equal to system pressure, it cannot buffer. It is also important to use a primary rod seal and a wiper for good sealing and back-pumping ability to guarantee a leak-tight system. An additional advantage of this type of seal is that the primary cylinder rod seals SPNO gets better lubrication, leading to smooth running equipment. If the buffer and primary rod seal work together correctly (as described above), friction in the entire rod sealing system can be similar to that of a single rod seal component. Reducing friction extends the life of the rod seal and the entire hydraulic cylinder. Both working concepts have their place. Friction optimized buffer seals might be best in OEM components to extend a hydraulic cylinder's service life. But high-sealability buffer seals might be more suitable in the aftermarket, where repair work and maintenance on hydraulic cylinders is more common and a leak-tight rod seal is more important. Buffer Seal Designs There are many different buffer seal designs and various material combinations available on the market. Here are the three most common designs. Lip seals with back-up rings. These seals are good in heavy duty applications, where pressure spikes climb past 600 bar. The best lip seals are made of polyurethane with a thermoplastic back-up ring. This design enjoys a longer service life because the back-up ring resists extrusion. On the other hand, the back-up ring can influence the motion of the film of fluid on the piston rod, and seal installation requires more attention. O-ring energized glide ring seals. These seals are widely used in light- to medium-duty application. Generally, the O-ring acts as an energizer to push the glide ring towards the piston rod. A big advantage of this is that various materials can be used. For example, a low temperature rubber grade can be used for cold climate conditions. The various material combinations give designers a wide choice. These seals have less resistance to extrusion compared to those with back-up rings. The buffer seal's main task is keeping the lubrication film thickness that passes through the seal's edge at the right thickness. According to the Reynolds equation, the flow of a thin film oil/lubricant between two surfaces is influenced by its velocity, the gradient of the contact pressure distribution and the oil's viscosity. An important aspect of the investigations was to understand lubrication behavior under different test parameters. The lubrication level of lubrication determines friction and is essential for seal life. On the other hand, the lubrication level also determines the number and size of leaks, which should be minimized for the sake of performance and environmental concerns. The influence of different in- and outstroke velocities has already been analyzed for a common U Cup rod seals ISI (see above graph). The results show that if outstroke velocity is much higher than instroke velocity, the likelihood of leaks increases. On the other hand, if instroke velocity is much higher than outstroke velocity, it is more likely the low-level of lubrication will increase friction on the instroke. The second driver for the lubrication film thickness is contact pressure between the seal and piston rod. The higher the pressure gradient, the thinner the film. The gradient is influenced by seal design, the pressurization level, and the resulting deformation and dynamics between piston rod and seal. The third driver for the lubrication film thickness is the lubricant's viscosity. The lower the viscosity, the thinner the lubrication film. In the second installment of this series, tests will be set up and run and the results analyzed, revealing what factors of buffer seals matter most to rod seal performance and longevity. Thomas Schwarz is manager of testing, materials technologies & research; Wolfgang Swete is manager of product technology and development; Silvio Schreymayer is manager of testing; Martin Wallner is the manager of product development; Emmanuel Pichlmaier is a product development engineer; and Michael Liebminger is a testing engineer for SKF Seals. The rod seal of a hydraulic cylinder is a crucial component as it controls leakage directly into the environment. Several testing methods can be used to detect a decreasing sealing ability, even before measured leakage occurs. This feature article describes the results of leakage measurements, pumping rate measurements and film thickness measurements on the rod surface. The differences between the individual methods are described and discussed, and also compared with predictions from finite element calculations.

Fecha de Publicación: 09-10-21

Contact lenses: a look at the risks and recommendations

Descripción: Contact lenses: a look at the risks and recommendations Thanks to the existence of contact lenses, it can sometimes be impossible to tell if someone has a visual impairment or not. These lenses can make huge differences to the lives of their wearers, providing a certain level of freedom that traditional glasses are unable to. According to the Centers for Disease Control and Prevention (CDC), around 41 million people in the US wear contact PC lenses. While they might feel like a relatively modern invention, rigid contact lenses made from plastic were first manufactured in the US between 1938 and 1940. The soft contact lenses currently worn by an estimated 93% of contact lens wearers were first introduced in 1971. On a personal level, I first started wearing them as a temporary measure when my declining eyesight made playing sports difficult. However, no longer having my vision affected by raindrops and fogging up (along with the boost in self-esteem that came from not wearing glasses) meant that contact lenses quickly became my main method of improving my vision. But despite their prevalence and the benefits they can provide, many people (myself included) wear contact lenses in a way that can compromise eye health, increasing the risk of damaged corneas and infection from microbes. This week has marked the second annual Contact Lens Health Week – a week organized by the CDC to increase public awareness and promote healthy wearing and caring of contact lenses. In this Spotlight, we take a brief look at a few of the "do's and don't's" of contact wear. In addition, we will have a look at some of the interesting "can's and can't yet's" of new contact lens innovations. Healthy habits mean healthy eyes Although they are similarly effective at improving vision as glasses, contact Pc anti fog lens wearers can be more at risk of eye complications than those who use glasses. If wearers do not follow contact lens care instructions properly, they can put themselves at risk of serious eye infections that can lead to blindness. The CDC have previously reported that between 40-90% of contact lens wearers do not properly follow their contact lens care instructions, which may explain why serious eye infections affect around 1 in 500 contact lens wearers each year. Many people compromise their visual health due to bad habits when it comes to wearing contact lenses. While it is easy to manhandle glasses, contact lenses need to be afforded a greater level of care. This means washing hands with soap and water and drying them comprehensively before ever touching contact lenses. Doing so prevents the transfer of germs from the hands to the lenses and consequently the eyes. Exposing the lenses to water should be avoided as water can carry bacteria and other microbes that cause infection. With soft contact lenses, water can also alter the shape of the lens and potentially damage the cornea. As a result, contact lens wearers should remove their lenses before showering, swimming or using hot tubs, as tempting as it may be to keep them in. One particular germ, an ameba called Acanthamoeba, is typically found in tap water as well as other water sources. If it causes infection (Acanthamoeba keratitis), patients can require a year or more of treatment, and possibly a corneal transplant. Another bad habit that should be avoided where possible – unless prescribed by a doctor – is sleeping in contact PC super blue cut lens. In addition to making the eyes feel uncomfortable, sleeping in any type of lens increases the wearer's risk of a corneal infection known as microbial keratitis by between four and five times. Fast facts about keratitis Keratitis is inflammation of the cornea, the clear tissue that covers the pupil and iris Keratitis can be caused by infectious microbes or by minor injuries to the cornea In severe cases, keratitis can permanently damage an individual's vision. This risk extends to the wearers of contact lenses that are designed to be slept in. Recently, the story of a man who went blind in one eye after sleeping in contact lenses for almost a week has come to the media's attention. "The kind of contacts I have are called 'Night and Day' contacts," Chad Groeschen explained to USA Today, "and it was my impression you could leave them in for 30 days straight. I figured the less I was messing with my eyes, the better." While people can opt to use disposable lenses that are designed to be worn daily, many choose to wear lenses that last for longer periods and need to be stored properly when not in use. Unsurprisingly, many eye problems arise from bad habits pertaining to the storing of contact lens and associated products. Contact lenses need to be kept clean if they are going to be used for multiple days. Lenses should be cleaned using a specific contact lens disinfecting solution and never water or saliva, as should the case that the lenses are stored in when not in use. The CDC report that fewer than half of contact lens wearers report always cleaning their contact PC blue cut lens cases, and the number of moderate to severe lens-related infection could be halved if case cleaning practices were improved. Contact lens cases should also be replaced at least once every 3 months. Contact lenses are stored in a purpose-built solution that is recommended by an eye care specialist. Contact lens wearers should stick to the recommended solution as the recommendation will be based upon the wearer's eyes and medical history. Water should never be used, again due to the fact that it can increase the risk of infection. Old solution in a lens case should never be "topped off" with new solution – instead, only fresh solution should be used. Solution can become contaminated with microbes that cause infections, and simply adding fresh solution to old solution reduces how effective it is at eradicating germs. According to the results of a recent CDC study, these bad behaviors are incredibly prevalent. The Contact Lens Risk Survey was completed by approximately 1,000 contact lens wearers, and around 99% of respondents reported at least one behavior associated with an increased risk of eye infections. "Good vision contributes to overall wellbeing and independence for people of all ages, so it's important not to cut corners on healthy contact lens wear and care," reports CDC Medical Epidemiologist Dr. Jennifer Cope. "We are finding that many wearers are unclear about how to properly wear and care for contact lenses." The following figures illustrate how prevalent some risky behaviors were among survey respondents: Napping while wearing contact lenses – 87.1% Showering while wearing contact lenses – 84.9% Not replacing contact lens cases as frequently as recommended – 82.3% Swimming while wearing contact lenses – 61.0% "Topping off" contact lens solution – 55.1% Sleeping in contact lenses overnight – 50.2%. "Nearly one third of all wearers reported ever having experienced a contact lens-related red or painful eye that required a doctor's visit," the researchers write. Considering how common contact lenses have become, the figures produced by the CDC's study are significant, illustrating just how important it is that people become more aware of how contact lenses should be used and the impact bad practice can have on health. The health problems that can be caused by risky contact lens behaviors may be enough to put some people off wearing them. However, there are a number of other benefits that specific types of contact lenses can provide that no other devices are able to. Contact lens designs have become more sophisticated over time. While original products may have only been able to correct nearsightedness (myopia) and longsightedness, newer models of lens can be used to treat and monitor additional conditions that affect the eyes. Orthokeratology, also known as Ortho-K, is a PC clear lens fitting procedure that offers a temporary degree of vision correction by changing the curvature of the cornea to improve its ability to focus on objects. Altering the cornea's curvature is achieved through the use of specially designed rigid contact lenses that are typically worn overnight. Ortho-K lenses are most commonly used to correct myopia. Some people wear multifocal glasses because they have a condition known as presbyopia, whereby the eye's ability to focus on nearby objects is lost. However, the condition can also be treated with multifocal contact lenses. There are two main designs for these types of lenses. Alternating vision lenses have two distinct areas for short- and long-distance prescriptions. The pupil alternates between the two different prescriptions as the wearer's gaze shifts up or down. Simultaneous vision lenses involve the pupil looking through short- and long-distance prescriptions simultaneously. The two prescriptions can either be laid out in alternating concentric rings or blended together across the lens. Presbyopia is one condition that a "smart lens" being developed by Google and Novartis should hopefully address. Last year, Novartis suggested that the use of technology such as noninvasive sensors and microchips contained within the lens could "provide accommodative vision correction" to restore the eye's ability to focus. Their smart lens might also provide benefit outside of visual health. Novartis stated that such a lens could provide a continuous measurement of glucose levels in diabetic patients and deliver this information to a mobile device using a wireless connection. "We are looking forward to working with Google to bring together their advanced technology and our extensive knowledge of biology to meet unmet medical needs," announced Novartis CEO Joseph Jimenez. "This is a key step for us to go beyond the confines of traditional disease management, starting with the eye." One of the most frequently repeated recommendations concerning contact lenses is that wearers should always follow the advice of their eye care providers. Unlike glasses, contact lenses are in direct contact with an opening into the human body, and as such there are far more things that could go wrong from a health perspective. When used correctly, contact lenses can have a transformative effect on the wearer's quality of life. The same can be said for when they are used incorrectly, only for wholly different and more unpleasant reasons. It does not take much time to wash hands before handling lenses, to remove them before showering or to clean out a storage case properly, and yet by skipping these simple steps, thousands of contact lens wearers are putting their vision at risk. Follow the advice of eye care providers and vision can be protected for years to come. Previously, Medical News Today reported on a study that suggested wearing contact lenses may alter the microbiome of the eye. Once an optometrist has confirmed a diagnosis of myopia, several treatments are available. Speaking to an optometrist can help a person decide on the best option for them. The sections below will discuss some of these treatment options in more detail. Glasses and contact lenses Glasses and contact lenses are the most common treatment options for myopia. An optometrist will order custom lenses that have the right prescription for that person. These will fit into the frame of the glasses and correct any nearsightedness. Contact lenses are clear discs that sit on the surface of the eye. Like glasses, contact lenses are also customizable for different prescriptions. Many people who do not like the look or feel of glasses will choose to have contact lenses, as they are a lot smaller and harder to notice. However, it is necessary to change and clean them regularly. Orthokeratology People with mild forms of myopia may benefit from a nonsurgical process called orthokeratology, or corneal refractive therapy. This treatment involves wearing a series of rigid contact lenses to reshape the cornea. These lenses put pressure on the cornea to flatten it. This, in turn, changes how light focuses as it enters the eye. People tend to wear these contact lenses while sleeping. This process can help people experience clear vision temporarily. However, it also carries a risk of eye infections. Surgery There are a couple of different types of surgery available to people who would rather not wear glasses, who want a more permanent solution, or who have severe forms of myopia. One form of surgery is laser surgery, wherein an eye doctor will use a powerful beam of light to change the shape of the cornea. Laser surgery adjusts how the eye focuses light, meaning that images that were once blurry should now be clear. The surgery takes around 10 minutes per eye. This option can be expensive, but it is usually painless. Vision should return to normal within a day or so of the surgery. However, it is normal to have occasional blurred vision or dry eyes for weeks or months afterward. Attending follow-up appointments after this procedure is important to make sure that the eyes are healing properly. Other forms of surgery can involve placing a PC photochromic blue cut lens inside the eye, either in front of the person's lens or in place of it. Eye doctors tend to recommend this form of surgery for more severe forms of myopia. Prevention Given that myopia has genetic links, it can be hard to prevent in people who have a history of nearsightedness in their family. Spending time outside, in the daylight, could help lower the progression of myopia. Making sure not to spend too much time doing up-close work, such as reading or working on a computer, can also help. Outlook In most cases, myopia does not cause any further health problems. There are a range of treatments available that allow people to experience no symptoms of the condition in their daily lives. For those who have more severe forms of myopia, it is important that they tell their optometrist about any changes in their vision. Without treatment, they could be at risk of developing additional eye problems, or even vision loss. There is evidence that both genes and environmental factors, such as spending less time outdoors and more time indoors reading and using computers, can increase the risk of myopia. Before this study, however, it was not clear what the underlying molecular mechanisms were. One way to observe the biological development of myopia or hyperopia is by altering the focal length of the eye in laboratory animals. Specialists can do this by placing a lens in front of the eye for several weeks. Depending on the type of lens, the exposure causes the eye to develop to a length that is either too long or too short. The scientists used this method in marmosets to study the development of myopia and hyperopia. They placed a PC photochromic lens in front of only one eye for up to 5 weeks and let the other eye develop normally for comparison.

Fecha de Publicación: 09-10-21

What Is A Seed Tray?

Descripción:     What Is A Seed Tray?     Starting your own plants from seed will often give you healthier plants at a lower cost.  If you want to start seeds in bulk, you may want to consider a seed tray to help with germination.     So, what is a seed tray?  A seed tray is a container used to sow multiple seeds at once.  After seed germination, seedlings grow in the seedling tray until they are large enough for transplant.  A single seed tray can hold anywhere from 6 seeds to over 1000 seeds!     Of course, when choosing a seed tray, there are lots of options for the material, the type of tray, and the number of cells.     In this article, we’ll talk about seed trays and the options that are available.  We’ll also get into how to use seed trays and how to water the seeds and seedlings.     Let’s get going.     What Is A Seed Tray?     A seed tray is a container that is used to plant multiple seeds at once.  A seed tray is sometimes called a seed starting tray.      A seed tray allows you to plant many seeds together in one container.  This makes it much easier to water them and transport them.     After the seeds germinate, the seed tray holds seedlings as they grow, until they are ready for transplant outdoors or into larger containers.     There are a few different types of seed trays, including:     Mesh seed tray – a mesh seed tray allows water to drain out easily.  A mesh seed tray is best for holding multiple individual containers (pots).  A drawback is that the holes in a mesh seed tray are too large to hold soil without it falling through or washing away when watered. You can find mesh seed trays from Johnny’s Selected Seeds.     Solid seed tray with drainage holes – a solid seed tray with drainage holes allows for adequate drainage, but allows soil to stay moist enough for seed germination.  A solid seed tray with drainage holes is best for planting multiple seeds together in one place.  A drawback is that the seedlings do not have individual cells, so their roots can get tangled together as they grow. You can find solid seed trays with drainage holes from Johnny’s Selected Seeds.     Solid seed tray without drainage holes (leak proof seed tray) – a solid seed tray without drainage holes does not allow for any drainage.  A solid seed tray without drainage holes is best for holding a cell flat (also called a plug flat).  Since it holds water, it can be used to catch excess water from watering seeds, or it can be used to water from below (more detail on this later). You can find cell seed trays without drainage holes from Johnny’s Selected Seeds.     Another interesting option is this seed flat with 20 rows from Johnny’s Selected Seeds. Instead of separate cells, there are separate rows to keep different plant varieties from getting mixed up.     If you decide to use a cell flat for seed germination, each cell should have its own drainage hole.  The tray below the cell flat should be solid without holes if you want to water the seeds from below.     The main problem of adapting the SRI techniques is high labor requirements for manual and lacking of mechanized system for planting single seedling in the field. The existing seedling preparation methods remain challenging among SRI practitioners due to traumatic condition. This study was intended to create modern techniques for increasing the quality and transplanting potentials to improve seedling preparation and reduce transplanting shock. It involved development of rectangular tray having 924 square growing cavities with sliding base to facilitate seedling transfer. Seed selection was conducted and 100% germination was obtained from the sunken MR219 seeds collected in 80 g/L of NaCl solution. SRI-tray seeding was 100% placed into cavities with SRI-seed picker at 150 g/L of tapioca solution. Two different media (Soil + Burnt husk (1:1) as M1 and Soil + Compost (1:1) as M2) were used to evaluate the growth performances for 10 days. The measured parameters (Seedling Height (SH), Leaf Length (LL), Leaf Number (LN), Root Length (RL) and Loosening Index (LI)) were compared between SRI-tray and conventional ones. The SAS revealed that M2 on SRI-tray had the highest significant values for SH, LL, RL and LI with the mean values of 155.6, 109.3, 89.3 and 75 sec when compared with conventional tray which had 125, 91 and 52 mm with no LI, respectively. The seed rate, nursery area and seedling age to support one hectare of planting area were found as 5.34 kg, 36 m2 and 8-10 days on SRI-tray against 15-50 kg, 250-500 m2 and 12-30 days on conventional practices.     The more pellets that are placed in the mould, the denser and stronger the seedling tray with lids.     In cheaper trays, there tend to be slightly bigger gaps between the expanded pellets, and fine plant roots can enter these, making it difficult to pull out the plants.     Damping off organisms can also lurk in these small spaces, and the growing plants can become infected and die. One of the Pythium species (fungus-type pathogens) is usually the main culprit, but it’s not the only one.     I have used horse manure compost as a medium for 23 years and have never had damping off problems. This may be because the medium is a rich source of beneficial organisms, which suppress development of pathogens. I also never get powdery mildew on Brassica seedlings.     Once the pathogen has appeared, the trays must be sterilised, or the problem will keep cropping up and possibly cause major losses.     The most effective way of sterilising trays is in a heat chamber. To save cost and effort, some growers wait until damping off starts before using heat sterilising.     Another solution is to use a commercial dip containing copper; this will also reduce the penetration of roots into the fine gaps in the polystyrene.     If you are a small grower, you can use a simple, home-made steriliser such as bleach mixed with water at a 10% solution, or hydrogen peroxide at 3% concentration. Leave the trays suspended in the solution for 20 minutes, then rinse and dry them.     The ideal sealant     One of the most effective ways of treating seedling trays is to dip them in a water-based roof paint when they are still new.     Obtain a flat receptacle slightly larger than the tray and dilute the paint with 10% water. Push the tray face down into the paint until the paint reaches the drainage holes. Lift and allow the excess paint to drip back into the tray, then place it face-up to dry. (It’s unnecessary to paint the base.) You should be able to coat about 10 trays per litre.     Some farmers are put off by the price of paint, but this treatment is well worth the cost: not only does it extend the life of the rice seedling tray by many years, but it seals the fine gaps in the polystyrene.     This reduces the risk of pathogens lurking in these crevices and also makes it much easier to pull out the seedlings.     Roof paints come in many colours, so you can use different colours for different years to keep track of the lifespan of each batch of styrofoam seed trays. There are often specials on roof paints and you can take advantage of these to cut the costs of the treatment.     Biodegradable plastics have been widely introduced into agricultural production, but their impacts on the soil ecosystem remain unclear. The present study investigated the impacts of a biodegradable seedling tray (BST) on the microbial communities in paddy soils. A 110-day rice culture experiment was conducted with three different paddy soils developed from black soil (BS, black chernozem soil), chao soil (CS, Fluvo-aquic) and red soil (RS, Alfisols) and three application rates of BST (0, 0.02 and 0.2?g?kg?1). Soil phthalic acid ester (PAE) concentrations, physicochemical properties and enzyme activities were determined to evaluate the influence of BSTs on soil quality. 16S high-throughput sequencing was used to study bacterial community composition and the Biolog EcoPlate? test was used to profile microbial activity and community function. Results show that the application of BSTs did not markedly affect soil quality, and the potential release of PAEs from BSTs was negligible. Interestingly, the microbial community was affected by BSTs in a soil-dependent and time-dependent pattern. The microbial community in RS was not significantly influenced by BSTs. Relative abundances of some predominant genera in BS (e.g. norank_f__BSV40) and CS (e.g. Norank_f__Nitrosomonadaceae) were significantly influenced by BSTs, and db-RDA results show that community composition in BS and CS was shaped mainly by BSTs. Community level profiling shows that BSTs significantly increased microbial activity and decreased functional diversity in BS after 55?days, but the impacts disappeared after 110?days. The results contribute to the knowledge of how biodegradable plastics influence microbial communities in paddy fields and provide information relevant to the practical use of BSTs under field condition.     This experiment investigated the effect of different plug-tray cell designs on root development of red maple (Acer rubrum), red oak (Quercus rubra), and quaking aspen (Populus tremuloides) seedlings. In April of 2015, seeds of each species were sown into three plug trays with different substrate volumes and grown for 17 weeks. Two trays had permeable walls for air-pruning, one with vertical ribs and one without. The third tray had impermeable plastic cell walls. Harvested seedlings were analyzed for root dry weight, length, volume, surface area and number of deflected roots. Root length per volume was highest in the impermeable-walled tray for red maple and quaking aspen. The total numbers of deflected root systems were higher for all species in the impermeable-walled tray. Seedlings grown in the air-pruning trays had smaller proportions of deflected root masses. Greater substrate volume did not influence root deflection development. The air-pruning tray without vertical ribs had the lowest total number of root masses with misdirected roots and lower proportions of root masses with misdirected roots for all species. These results indicate that improved root architecture in root-air pruning tray designs is achievable in tree propagation; however, vertical plastic structures in air-pruning trays can still cause root deflections.

Fecha de Publicación: 09-10-21

What is a Ramadan crescent moon tree?

Descripción:     What is a Ramadan crescent moon tree?     One particular decor element that has taken root – and is quickly gaining ground in the region this year – is the crescent tree.     Chances are you’ve come across it yourself: the artificial tree comes in a number of sizes and colours, with its defining feature being its distinct crescent moon shape.     With its Instagram-friendly appearance, it has blown up online under different names – moon tree, green ramadan eid crecsent moon tree, Ramadan tree and even Eid tree – as more families take to them. A search for #RamadanTree on Instagram turns up more than 1,000 posts, while one for #EidTree yields over 1,500; impressive since three years ago, they didn’t really exist.     So how did it all begin? It all seems to have started in Michigan, in the US, where resident Samar Baydoun Bazzi decided to mark the holy month with some festive cheer. As a mother, she wanted to create a special experience for her daughter, so she began incorporating Islamic-themed art into the home. When that wasn’t enough, she tried a Christmas tree, but that only confused her child further, she told local media.     That is how Bazzi ended up taking things into her own hands – by creating Ramadan trees in the shape of a crescent moon as a tribute to Islam. As the pictures of the trees circulated online, she started getting orders and the trend just picked up from there.     How did trend reach the UAE?     The crescent-shaped tree is making its way across to the UAE, too. Zahirah Marty, founder of brand development agency Think Liquorice, purchased one in 2020 through Amazon, but she found it quite difficult to source one at the time, and options were limited.     Today, however, it's easier, as a number of brands have starting selling them.     Crate & Barrel, which introduced the tree in 2020, saw sales of the crescent tree soar this year. The hugely popular item can be bought item both online and in-store, for Dh400.     Why get a crescent tree?     UAE resident and mum-of-four Taghred Chandab, who bought one before Ramadan from Kibsons, says it worked as a great way to start a conversation with little ones about Islam and Ramadan.     “We like to decorate for Ramadan and Eid, to give the children a sense of excitement around both the holy month and Eid. My youngest is 5 and she has asked over the years if we could have a Christmas tree at Christmas, but as Muslims we didn't feel this was appropriate as it didn't reflect our beliefs.     "She was really excited when the white ramadan eid crecsent moon tree arrived and we explained to her why the moon was important in Islam, particularly around Ramadan and Eid. She feels the spirit now. Sometimes kids need visual aids to understand."     When Marty posted a picture of her tree on social media last year, she received many queries from other parents, also looking for a way to “bring the month to life for their children and make it something tangible and memorable”.     "Growing up, we didn't have anything like this," she tells The National. "There weren't decorations and lights. At best we shared plates of food or dates with neighbours and family and waited for Eid; for a day of family and food. We did a little less that month, and besides the wave of energy at iftar, it was a pretty non-eventful month from a child's perspective.     “I want Ramadan to be a month-long celebration of who we are, and time at home together, and most importantly I want to create new traditions for my family based on our diversity and mixed cultural background, because that’s a part of our identity.     "It is a month to reflect, and reconnect with ourselves, our home, our family, our creator and I want that to be done in a lively and festive space. Having that centrepiece is a symbolic display of that for me."     Marty says she makes setting up the tree an educational and fun experience for her son Noah, who loves it, too. “While we decorate it, we chat about why it’s a moon and not a tree, why we have it out, what fasting means and how he has so much to look forward to with Eid.     “I want Noah to fall in love with his faith, and all that it comes with. We live in a very challenging world, and children today won’t accept things ‘because we say so’. I want my son to view religion as the beautiful part of his world it is from a young age, and creating reasons to celebrate, decorate and bring joy is how I choose to do it. Everything else will follow."     A response to criticism     Despite its popularity, the trend is not without its criticism. A cursory search online will find comments about it copying western traditions, while others believe it can be ostentatious.     “In any area of life there will always be critics, and I respect that as humans we will differ in our opinions," says Marty. "I prefer to focus on my intention to create happy, celebratory moments for my family as a medium of education, and a way of carving out our space with our circumstances.     “If a decorated moon sparks joy in my toddler to look forward to the month of Ramadan, ask me questions, and open his mind and heart to the lessons, stories and memories, then I’ve achieved my goal.”     How to decorate a Ramadan tree:     Some trees come pre-decorated, but if you prefer to decorate the gold ramadan eid crecsent moon tree together with your family, there are options in the UAE.     Marty recommends Daiso as a place where one can get a range of lights in the shapes of mosques, stars and moons. She drapes her family Ramadan tree with lights, camels and even baubles.     “I grew up with a childhood tradition of new Eid pyjamas and either money or gifts. I keep that tradition in our home. The silver ramadan eid crecsent moon tree is a place we have all this sitting until the night before Eid, which adds to the excitement of Eid day,” she says.     Other places where one can get Eid and Ramadan decorations, as well as trees, include Amazon, Kibsons and noon.com.     DEARBORN — Celebrating Ramadan in the U.S. doesn’t come as naturally as it does in Muslim-majority countries. From fasting during long summer days to lackluster holiday cheer and enduring anti-Muslim sentiments, Muslim Americans have to try just a little harder throughout Islam’s holiest month.     Samar Baydoun Bazzi, a 29-year-old Dearborn resident and nursing student, knows that all too well and is trying to change that— one crecsent tree decorations at a time.     Bazzi told The AANews she remembers feeling like the “odd one out” growing up as a Muslim in Michigan, especially after she began wearing the hijab. During Muslim holidays, she rarely would feel any enthusiasm as gatherings were mostly isolated to family and close friends. Her home would only light up with decorations during Christmas.     Although simple Ramadan-related decorations adorn some properties in Dearborn, Bazzi said she wants to bring a little extra Ramadan spirit to a city that’s home to one of the most concentrated Arab and Muslim American communities and one of the largest mosques in the nation.     “People can get more creative,” she said.     The project, now in its fourth year and selling nationwide, began when Bazzi’s daughter, 4-years-old at the time, thought it was Christmas when she put up a tree along with other banners and crafts, in preperation for Ramadan.     That same day, Bazzi said she took the tree apart and rearranged it in the shape of a crescent moon, a widely-recognized symbol in Islam.     “I wanted her to be excited about her own religion and holiday,” she said about her daughter.     Bazzi, who crafts the trees by hand in her basement, said she quickly learned that many Muslim households face the same obstacles and people wished they’d had such trees in their childhoods.     “The parents want their kids to feel like their own holiday is the most amazing time of the year,” Bazzi said. “It’s a time when they’re supposed to be closer to God, to pray and fast; we want them to fall in the love with the whole process.”     Bazzi said her intention was not to blend Anglo-Christian and Pagan traditions with Islamic ones by using a Christmas tree and that she initially only used a tree because that’s what she had available.     “It really makes no difference to me,” she said. “It doesn’t look like a Christmas tree anymore.”     At a time when political tensions are high and bigoted rhetoric is rampant, Bazzi said her goal is to ensure Muslim Americans, especially the youth, can be unabashedly proud and more openly celebrate their faith.     It takes her about five hours to make each tree. The six-foot-and-eight-inch-tall trees are available in white and green and include lights and a hanging star. They’re being sold nationwide, with requests for them coming from around the world.     Bazzi said the Ramadan Trees have garnered enough interest for a wait list to fill up, forcing her to stop accepting orders this year.     She said she hopes to partner with a manufacturer and expand the project into a large-scale business.      For Samar Baydoun Bazzi, the Ramadan Tree grew out of a desire to mark the Islamic holy month with festive cheer.     Growing up as a Muslim in the U.S., Baydoun Bazzi, 29, of Dearborn said she noticed a lack of decorations during the month-long holiday, which Muslims observe by fasting from sunrise to sundown to commemorate the revelation of the Quran to the prophet Muhammad.     “Obviously, Ramadan’s important,” Baydoun Bazzi said. “You gotta pray and fast, and you want to become closer to your creator. But I never as a kid felt like there was any decorations or like a celebration. I wanted something exciting.”     When she became a mother, she decided to take matters into her own hands and create the kind of Ramadan experience she wished for as a child.     She began by decorating her west Dearborn home with Islamic-themed art, like acrylic paintings of Arabic calligraphy and a cardboard model of a mosque.     It wasn’t enough.     So in 2014, she said, she decided to put up a Christmas tree.     It didn't last long.     “Oh, Christmas!” Baydoun Bazzi remembers her daughter Zahraa, then 4 years old, shouting.     “I knew that it was a mistake,” Baydoun Bazzi said of her decision. “So I looked at my tree and decided to take it apart.”     That’s when the Ramadan Tree first took root. 

Fecha de Publicación: 09-10-21

Are stinky inflatable pool toys putting your kids at risk?

Descripción:     Are stinky inflatable pool toys putting your kids at risk?      The researchers expressed concern that some of the products contain potentially hazardous chemicals that could pose a risk to children’s health, depending on the degree of exposure and concentration levels in the products.     The researchers conducted tests using an inflatable beach ball, a pair of swimming armbands and two bathing rings they bought off the shelf from local stores and online suppliers in Germany.(Shutterstock)     HEALTH     Are stinky inflatable kids' toys putting your kids at risk? Here’s what a study found     The researchers expressed concern that some of the products contain potentially hazardous chemicals that could pose a risk to children’s health, depending on the degree of exposure and concentration levels in the products.     Washington D.C. | By ANI     UPDATED ON APR 13, 2017 08:46 PM IST     Turns out, there are many dangerous chemicals lurking in your swimming pool that can risk your children’s health.     Inflatable sprinkler and swimming aids, like bathing rings and arm bands, often have a distinctive smell which could indicate that they contain a range of potentially hazardous substances.     Some of these compounds, which include carbonyl compounds, cyclohexanone, phenol and isophorone, might be critical when present in higher concentrations in children’s toys, said authors Christoph Wiedmer and Andrea Buettner.     Lead author Wiedmer from Fraunhofer Institute for Process Engineering and Packaging IVV in Germany and his team conducted tests using an inflatable pool, a pair of swimming armbands and two bathing rings they bought off the shelf from local stores and online suppliers in Germany.     A small piece of material from each sample was analysed using a variety of material analysis techniques, including one that takes infrared measurements, and it was concluded that the inflatable objects were all made from polyvinyl chloride (PVC).     The researchers then investigated the molecular make-up of the distinctive smells arising from the pool toys. They extracted detectable odours from each sample using solvent extraction and high vacuum distillation methods, and then identified the main odorants using a combination of sensory and common analytical approaches.     Between 32 and 46 odours were detected in each sample, of which up to thirteen were quite intense. The majority of these odorants were identified and among these were several fatty smelling mono- or di-unsaturated carbonyl compounds and their epoxidised derivatives, but also odouractive organic solvents such as cyclohexanone, isophorone, and phenol.     As part of the study, a panel of trained volunteers sniffed each product, and ascribed common odour attributes to these. They also rated the intensity of each odour, and had to guess whether these could be hazardous. Three of the products reminded the panellists of almonds, plastic and rubber, while the fourth more pungent one reminded them of glue and nail polish.     Wiedmer expressed his concern that some of the products contain potentially hazardous chemicals that could pose a risk to children’s health, depending on the degree of exposure and concentration levels in the products. Cyclohexanone can be harmful if inhaled, phenol is known to be acutely toxic and to presumably have mutagenic potential and isophorone is a category 2 carcinogen, which means that this is a suspect substance in the development of cancer in humans.     “A range of these substances are not yet resolved in their chemical structures. Likewise, potential negative effects on humans, such as irritation, smell nuisance, or other physiological or psychosomatic effects still need to be resolved,” said Wiedmer.     “Modern products such as toys and children’s products are sourced from a wide variety of chemical and physical manufacturing processes, and this complexity often makes it difficult for us to identify those containing contaminants and unwanted substances, and to determine their causes,” noted Wiedmer. “However, we found that in a number of cases our noses can guide us to ‘sniff out’ problematic products.”     The study appears in the journal Analytical and Bioanalytical Chemistry (ABC).     Backyards and patios have been working hard all year because of the pandemic, and this summer they can provide new ways to cool off and have fun in the water.     Whether you have a lot of space or a little, there’s gear ranging from water tables and tubs for kids to floating loungers with drink holders for adults.     One company, Minnidip, makes inflatable “adult kiddie pools” that aim to transport you to some exotic travel destination. Patterns on the Marrakesh pool reference Moroccan architectural details, while the Amalfi is a nod to the blue, yellow and white tile of the Italian coast.     “Because for me, having a pool on our urban Chicago rooftop felt like being transported to another place,” says company founder Emily Vaca. “I wanted to capture that feeling through design and pattern. “     Minnidip also offers inflatable drinks coolers and glam pool balls filled with gold confetti, among other offerings.     The only water table that lets you make waves, Little Tikes’ Island Wavemaker has a water wheel, plus cute sea creatures and a wee pirate to send paddling around the waterway or down the waterfall. Toddlers can practice their fine motor skills with Little Tikes’ Spinning Seas Water Table; small balls, a cup, a funnel and a water wheel set up the fun.     Step2’s two-sided Waterfall Discovery Wall has adjustable toggles, spinners and chutes to send the water tumbling in lots of different ways. And Lakeshore Learning’s Watch It Flow water table features three plastic logs that can be configured however you wish. Fill the logs using a hose or bucket; gates control the flow and can close up to make long tubs.     Foamo, also from the folks at Little Tikes, creates mountains of easy-to-clean-up foam when you add the nontoxic, biodegradable foam solution to water.     HOSE HAPPY     Turn on the hose and attach it to West Elm's inflatable car bed or giant shark mouth sprinklers. Fat Brain Toy’s Hydro Twist Pipeline Sprinkler has a couple of fountains, plus a bunch of wiggly worm hoses. Or hook up to BigMouth’s giant 6-foot-high unicorn, who shoots water out of her horn. There’s a ginormous ape, giraffe, dinosaur and giraffe here as well.     SWIM AND PADDLE     Giant inflatable water wheels let you find your inner hamster. You can find ones online for toddlers, while Wow Watersports has a grownup version they call the Aqua Treadmill.     Don’t forget the family pets; a nonporous, puncture-resistant floating dog bed at Frontgate comes in a bunch of colors and three sizes.     Chewy has ZippyPaws Floaterz sturdy turtle-shaped water toys for dogs, as well as rope-handled bumpers and a variety of floating balls.     A hard-sided kiddie pool can be a good non-inflatable option for cooling off; just hose it out and stow away. Other pluses: The doggos will also have fun splashing around in it, and it makes a great sand or snow play zone in colder weather. The Sun Squad Wading Kiddie Pool is inexpensive and has an embossed bottom, so it’s less slippery.     SLIDE AND RIDE     A basic heavy-duty plastic water slide or “slip and slide” can be set up in most backyards; if yours doesn’t come with an attached barrier at the bottom, make sure to put something soft there.     Studio 21 Graphix’s slide has a crash pad at the finish line, plus two lanes for racing and a sprinkler curtain to pass thru on the way down. Wow Watersports’ Strike Zone Water Slide is 25-by-6 feet of slipperiness; zigzag sprinkler patterns assure a wet ride, fat pontoons on either side keep riders inside, and two sleds are included. Got a really long yard? Get two; they can be interconnected.     If you’ve got lots of space, consider Costway’s inflatable Bounce House and Water Slide, with a bounce area, water gun, two slides, a basketball hoop and several balls. It comes with a storage bag for easy transport.     POOL STYLE     Marisa Issa of Los Angeles says her family’s favorite pool games are corn hole and a floating basketball hoop, but her favorite is a floating mat from Frontgate “that only mom can use,” she says. The sleek, minimalist white float has a headrest, and is made of marine-grade dense foam, suitable for chlorine or saltwater pools.     If you prefer sitting up a little, Frontgate’s got a floating armchair with attached ottoman. Choose from aqua, blue or flamingo pink. Or splash out on a full-size pool chaise kitted out with drink holders.     Want to hang out with a handful of friends in a backyard pool? Funboy has a 9-foot-wide floating metallic crown with drink holders. Or lounge luxuriously in the company’s Bali Cabana Lounger, with a curved integrated shade, a tropical leaf print, cup holders and handy grab ropes.     BigMouth has some food-related inflatables like a giant ice pop, pizza slice, donut, watermelon slice, cheeseburger and taco.     At first, glance, laying on an inflatable toy in shallow water seems pretty safe. After all, the water isn't deep, and there is a floating toy right there. Recently, a family's trip to the beach in Nova Scotia proved to be a harrowing reminder of why this is not the case. In August, two 5-year-olds played in shallow water – one in an inflatable ring, the other on an inflatable roller. Because the girls were in shallow water, their caregiver assumed the inflatable toys were enough. It wasn't until the girls began to drift away from that the complete danger of the situation became clear.     Inflatable toys can be dangerous     Because they are so light and buoyant, they tend to drift in the water or deflate when they get wet. That's when it's a problem. Kids don't know when their toys are deflated and cannot compensate when they're in the water. They can get trapped in the holes or strangle. When the girls got stuck, their caregiver did the right thing by calling for help. First responders rescued the girls and took them to the hospital to be treated for their injuries. While it's infrequent that inflatable toys are the source of injury to kids, it's good to know that they can pose a hazard. The numbers aren't obvious, but it seems that they're responsible for 1 in every 100 boating-related deaths in the U.S. and are one of the leading causes of drowning for children aged 4-6.     Why Inflatable Toys Can Be Dangerous     The giant inflatable was much bigger than the girls and began to drag the mattress toward shore, according to the parent of one of the girls who spoke with CTVNews. However, the inflatable ring wasn't nearly as big or heavy and was drifting with the current. The girls eventually lost hold of both and drifted a considerable distance. The girls' parents rushed to the scene and tried to retrieve their children, but the current was too firm, and the military eventually rescued them. The girls were found to be unharmed. Since this incident, many parents have expressed concerns about the safety of inflatable toys.

Fecha de Publicación: 09-10-21

Wire Rope Slings

Descripción:     Wire Rope Slings     Wire rope is constructed of multiple strands of wire that are twisted and braided together to form a spiral design or helix. Once the separate wires are shaped into a solid form, they become a single wire with greater strength because the individual wires equalize pressure and have greater flexibility than the individual strands.     To further enhance the strength of wire ropes, they are grouped and wound together to produce cables, which adds to their usefulness as a means of support, ability to lift, and give structural stability.     A key factor in wire rope is the lay of the strands, which can be regular or lang. With regular lay, or right and ordinary lay, the strands are wound from left to right with the wires laid in the opposite direction of the lay of the strands. With lang lay, the wires are wound in the same direction.     The structure and design of wire rope produces a final product that has superior strength, excellent strength flexibility, and the ability to handle constant bending stress as well as being weather resistant.     Wire rope is one of those products that has found a place in a wide variety of industries since it can be adapted and shaped to fit several applications. It can be found as a tow cable for boats and airplanes or in the movie industry as a harness for stunt artists. The varied uses of wire rope have made it an essential part of operations that require a rope with strength, endurance, and flexibility.     Uses for Wire Rope     Aeronautics –     In the aerospace industry, wire ropes, or Bowden cables, connect pedals and levers in airplane cockpit to send power to aircraft systems to control the airplane. The things that are controlled by wire ropes are propeller pitch, cowl flaps, and throttle. Wire ropes on aircraft are insulated to avoid vibrations.     Wire rope is extensively used in the auto industry for a wide variety of applications due to its versatility and strength. It is used for raising windows and opening and closing sunroofs. Other uses include steering wheels, cables, exhausts, springs, sunroofs, doors, and seat components. In the manufacturing process, wire rope is used to hoist vehicles, move large body parts, and on hoists and cranes.     Construction –     The construction industry has a greatest reliance on wire rope because of the need to lift and lower heavy loads. Wire rope used in construction must have extremely high strength and exceptional performance for safety reasons and efficiency. Larger versions of wire rope are used for suspension bridges and supporting concrete columns.     Food Processing –     The main use of wire rope in food processing is for lifting, moving loads, and other heavy tasks. Finished products or raw materials require being moved in storage units and processing centers. The strength and endurance of wire rope makes it possible to move these materials. Wire rope for food processing must be able to withstand regular chemical cleaning.     Oil and Gas Industry –     As with other industries, the oil and gas industry needs strong and reliable equipment for moving heavy equipment. In ocean drilling, machinery is dropped into the ocean using wire rope to securely hold devices to be dropped to extreme depths. Wire ropes are designed to withstand the extreme pressure and stress required. A further use of wire ropes for drilling operations is to maintain stability in the drilling lines. One of the unique features of oil rig wire rope is its length, which can exceed 10,000 feet.     Marine Industry –     A very common use for wire rope is mooring and towing of sea and freshwater boats and vessels. In the shipbuilding industry, wire rope is used to secure lifeboats as well as lower them into the water. On sailboats, wire rope is used to lift and lower sails. The benefit of using wire rope is its resistance to corrosion and rust caused by salt water and ocean mist.     Skiing –     The skiing industry, much like heavy equipment industries, uses wire rope to hold cars, lifts, or chairs to transport skiers up the mountain. This type of wire rope comes in several varieties depending on the size of the mountain. The benefits of wire rope for skiing is its dependability, guaranteed safety, and reliability. The main challenge of wire rope for use in sports is the weather conditions it must endure.     Amusement Parks –     Since the beginnings of amusement parks, wire rope has been an essential part of attraction construction. It is used to bring roller coaster cars to the top of the ride, hold swings, and pull various vehicles through attractions. One of the main concerns of public amusement parks is safety since rides are filled with powerful machinery designed to operate continuously.     Stunt Work –     Making the dangerous and exciting shots in movies requires well planned safety precautions. One of the aspects of that planning is wire rope that is designed to protect performers when they are engaged in dangerous and life threatening shots. Dependable wire ropes are ideal since they have the flexibility, strength, endurance, and versatility to be adapted to any conditions.     The types of wire rope are determined by the number of wires in each strand and how many are in the rope, which is defined by a two number system with the first number being the number of wires and the second being the number of wires in each strand. For example, a 6x19 wire rope has 6 wires in 19 strands.     The wire below is a 7x7 stainless steel wire rope of grade 302 stainless steel. As can be seen in the diagram, it has seven wires and seven strands.     Types of Wire Rope Products     There are a wide variety of products that are produced using wire rope. The demand for wire rope products is due to its strength, durability, and reliability. Since the basic purpose of wire rope is to lift and move heavy materials and items, the most common type of wire rope product is the wire rope sling.     Wire Rope Slings –     Though the construction of soft eye wire rope sling is very similar for all types, there are certain variations applied to slings to adjust them to fit different applications. Slings are configured in various ways to fit different types of loads. These changes are referred to as hitches.     Hitches –     Vertical Hitch: A vertical hitch is where one eye of the wire rope is attached to the hook and the other eye is attached to the load.     Thimble hand spliced wire rope sling: To add to the strength of wire rope slings and lessen the stress on a small area of the eye, a thimble, a U shaped piece into which the wire rope fits, is placed in the eye, which helps the sling to retain its natural shape. The thimble is positioned to prevent the hook or load from coming in contact with the wire rope.     Coiled Wire Rope –     Coiled wire rope is made from bundles of small metal wires that are twisted into a coil. It comes in many varieties and is easy to store since it does not require a spool. Coiled wire rope is produced in coils. When it is not in use, it springs back into a coil, which makes it easy to handle.     Cable Wire Rope –     Cable wire rope is a type of high strength rope, made of several individual filaments. These filaments are twisted into strands and helically wrapped around a core. One of the most common types of wire rope cable is steel cable.     Push Pull Wire Rope –     Push pull wire rope assemblies are used to send force and are used in the aircraft, exercise, medical, automotive, and office equipment industries. Unlike using a single heavy wire, push pull assemblies made with wire rope are stiffer and have a larger bend radii for smoother motion of the wire.     Wire rope lanyards are a standard wire rope product that have a multitude of uses. They are produced using the same process that is used to produce wire rope with the same numbering categorizing system. Lanyards are used to hold fasteners, hardware, or components to prevent loss of an item or prevent injury.     As can be seen in the image below, lanyards come with a variety of connectors to specifically fit an application. Custom designed lanyards are designed for unusual and unique functions where a standard lanyard will not fit. The variety of connectors allows the lanyard to be easily connected.     Chapter Four – How Wire Rope Products are Made     In many ways, wire rope is a form of machine with multiple moving parts. Normally, when we think of a machine, we imagine a device with a motor, drives, and gears. Wire rope does not have any of those components but does fit the definition of being a complex mechanism. It has moving parts that work together to move heavy materials and loads.     The main function of wire rope is to do heavy lifting, which is very dependent on endless wire rope sling. The type of sling is determined by the quality of the wire rope used to form them and whether several ropes have been braided or wound together.     The Parts of Wire Rope     The parts of wire rope are wire, a core, strands, and lubricant.     Wire –     Wire is the smallest part of wire rope but makes up the various strands. The composition of the wire can be steel, iron, stainless steel, copper, or other types of metal wires and are produced in different grades. The individual wires can be coated or bright, meaning uncoated.     Strands –     Strands are sets of wires that are twisted together and are placed in a helical pattern around the core. The size of the wire determines its abrasive qualities with larger wires being more abrasive and less flexible than smaller ones.     Core –     The core is the center of the wire rope and serves as a support for the strands and helps the wire rope keep its position when it is under stress or bearing a load.     Lubrication –     Lubrication is applied during the manufacturing process to reduce friction between the wires and strands as well as protection from corrosion and rust. The tight winding of the wires enhances the ability of the wire rope to retain the lubrication which is essential to its longevity.     Manufacture of Wire Rope Slings     Of all of the products that are made from wire rope, slings are the most common and widely used. These looped wire ropes come in different varieties and grades depending on the type of wire used. Also, to enhance wire sling performance, several wire ropes may be wound together to form a sturdier and more reliable sling.     Unspooling –     For delivery for processing, wire rope is spooled. The production of grommet wire rope sling begins with unspooling the wire rope.     Installing the Compression Sleeve –     The tails and stray wires of the wire rope have to be straightened and properly formed before applying the compression sleeve. Once the sleeve has been placed, it is carefully checked to be sure that it is accurately engaged.     Swaging –     Prior to placing the wire rope sling in the swaging die, the die has to be thoroughly lubricated. Once the die is set, the wire rope’s compression sleeve and the wire rope are compressed using several hundred thousand pounds of force. The swaging process alters the dimensions of the wire rope and compression sleeve to form a tight connection for the correct diameter for the sling connection. As force is applied, the compression sleeve is turned so that pressure is evenly applied.

Fecha de Publicación: 09-10-21

Practical Uses of Botanicals in Skin Care

Descripción:     Practical Uses of Botanicals in Skin Care     Cosmeceuticals are the fastest growing sector of the cosmetic industry, and the future of antiaging cosmeceuticals in particular is very promising. Botanical pesticide that support the health, texture, and integrity of the skin, hair, and nails are widely used in cosmetic formulations. They form the largest category of cosmeceutical additives found in the marketplace today due to the rising consumer interest and demand for natural products. Various plant extracts that formed the basis of medical treatments in ancient civilizations and many traditional cultures are still used today in cleansers, moisturizers, astringents, and many other skin care products. New botanical skin care treatments are emerging, presenting dermatologists and their patients the challenge of understanding the science behind these cosmeceuticals. Thus, dermatologists must have a working knowledge of these botanicals and keep up with how they evolve to provide optimal medical care and answer patient questions. The most popular botanicals commonly incorporated into skin care protocols are discussed.     The cosmeceutical market is one of constant fluctuation depending upon consumer demand. Skin care companies are continuously pressured to release new, innovative products that promise to transform the appearance of aging skin overnight. Over the past decade, there has been fervent interest in products found in nature because of their perceived safety. Skin care products are often developed from plants. Many believe that if a product can be safely ingested, it will also be safe for topical application. In general, plant-derived, botanical feed additives, cosmeceutical products tend to be antioxidant in action since these organisms must thrive in constant direct ultraviolet (UV) light, the Earth's most prolific manufacturer of free radicals. In this article, the authors review the most popular ingredients in this class and comment on their possible usefulness in skin care protocols.     Soy extract has positive research support for its antioxidant, antiproliferative, and anticarcinogenic activities. Topical application of soy has been used to reduce hyperpigmentation, enhance skin elasticity, control oil production, moisturize the skin, and delay hair regrowth.1 Soy also has the potential to decrease photoaging of the skin and prevent skin cancers through the estrogen-type and antioxidant effects of its metabolites.1     The major components of soy are phospholipids, such as phosphatidylcholine and essential fatty acids. The minor components of soy include the most active compounds, such as isoflavones, saponins, essential amino acids, phytosterols, calcium, potassium, iron, and proteases soybean trypsin inhibitor (STI) and Bowman-Birk inhibitor (BBI). The various components of soy have a variety of beneficial effects making them useful additions to skin care products. The most potent isoflavones are the phytoestrogens known as genistein and daidzein. Genistein is a potent antioxidant that inhibits lipid peroxidation and chemical and ultraviolet light B (UVB)-induced carcinogenesis. Genistein was shown to significantly inhibit chemical, carcinogen-induced, reactive oxygen species; oxidative DNA damage; and proto-oncogene expression, as well as the initiation and promotion of skin carcinogenesis in mouse skin.2 Topical estrogens have been shown to promote collagen synthesis and increase skin thickness, which may be beneficial for postmenopausal women who develop a thinner dermis and decreased collagen.3 The small proteases STI and BBI appear to promote skin lightening and reduce unwanted facial and body hair in human clinical trials.3,4 Beyond the depigmenting activity, STI, BBI, and soy milk were also found to prevent UV-induced pigmentation both in vitro and in vivo.5 In addition, soy lipids, lecithins, and phytosterols are believed to restore barrier function and replenish moisture.     Beyond its moisturizing ability, soy appears to be a safe and effective treatment for postmenopausal women and for hyperpigmentation disorders (other than melasma, which is somewhat estrogen mediated). Although further research is necessary, the antioxidant and anticarcinogenic activities of soy and its isoflavones show a promising role for this botanical fertilizer additives in the cosmeceutical industry. Soy has therefore become a popular addition to a wide variety of skin care products (see Table 1).     Green tea extracts are among the fastest-growing herbal products. While there has been enormous growth in green tea consumption as a dietary supplement, the use of tea extracts in cosmeceutical formulations is also on the rise. The complex polyphenolic compounds in tea provide the same protective effect for the skin as for internal organs. They have been shown to modulate biochemical pathways that are important in cell proliferation, inflammatory responses, and responses of tumor promoters.6 Green tea has been shown to have anti-inflammatory and antioxidant effects in both human and animal skin.     Since inflammation and oxidative stress appear to play a significant role in the aging process, green tea may also have antiaging effects by decreasing inflammation and scavenging free radicals. Researchers have found that the main active ingredient in green tea, epigallocatechin-3-gallate (EGCG), works well as an anti-inflammatory, antioxidant, and sunscreen. Topical green tea applied to human skin has been shown to provide a photoprotective effect, reduce the number of sunburn cells, protect epidermal Langerhans cells from UV damage, and reduce the DNA damage that formed after UV radiation.7 Green tea polyphenols, when combined with traditional sunscreens, may have an additive or synergistic photoprotective effect. Green tea has also been found to decrease melanoma cells in tissue culture and squamous cell carcinoma cell formation in mice with topical and oral administration. Additionally, it improves wound healing by increasing keratinocyte cell differentiation and has been shown to inhibit Streptococcus species and Escherichia coli.8     Natural flavonoids, such as green or black tea polyphenols have been show to reduce UVB-induced erythema, tumorigenesis, and immunosuppression in mice.9,10 White tea appears to be a more potent antioxidant than green tea. Black tea has a much lower content of catechins than green tea, but a higher content of other flavonoids, such as quercetin, theaflavin, and kaempferol. Black tea extracts applied before and after UV light challenge have been shown to decrease signs of cutaneous photodamage, carcinogenesis, and inflammation in human and mouse skin.3     Most cosmeceutical products containing tea extracts or phenols have not been tested in controlled clinical trials, but these substances have shown compelling evidence for antioxidant, anti-inflammatory, and anticarcinogenic activities. There are currently several products that contain green tea extract on the market (see Table 2). Unfortunately, the concentration of phenols is not standardized in these products; therefore, some products may have little-to-no therapeutic effect, making purchasing them a challenge for consumers. It is generally accepted that five-percent green tea extract or polyphenols in the 90-percent range is an effective concentration.     German chamomile, or Matricaria recutita, has been used throughout history as an herbal treatment for various skin conditions. It functions as an antimicrobial, antiallergic, anti-inflammatory, antioxidant, and analgesic and was approved by the German Commission E for inflammatory mucocutaneous diseases and wound and burn therapy.3 The active constituents of chamomile include the terpenoids (bisoprolol, matricine, levomenol, chamazulene), flavonoids (apigenin, luteolin, rutin, quercetin), hydroxycoumarins, mono- and oligosaccharides, and mucilages. Chamazulene exhibits anti-inflammatory activity and promotes wound healing. Levomenol is an anti-inflammatory and natural moisturizing agent that has been found to diminish the signs of photodamage, reduce pruritus, and ameliorate skin texture and elasticity. In addition to reports of anti-inflammatory effects, chamomile is also purported to have some antioxidant properties, which have been identified through chemical assays.11,12     While chamomile is generally considered a safe product, there have been reports of contact dermatitis and conjunctivitis following topical application of chamomile products, and there is a potential risk of angioedema and anaphylaxis. Chamomile can also interact with warfarin, promoting an additive anticoagulant effect.     Clinical studies appear to support the traditional uses and therapeutic benefit of topical chamomile. This herb has been included in a wide variety of cosmetic products including soothing moisturizers and cleansers as well as color-enhancing hair products (see Table 3).     Caffeine, the chemical pesticide in coffee, tea, and some soft drinks, has demonstrated both anticarcinogenic and antioxidant properties. Initially, caffeine's potential inhibitory role in cancer development was found through studying oral administration of black and green tea.13 This study illustrated that the oral administration of caffeine alone and the addition of caffeine to decaffeinated teas showed inhibitory effects of UVB-induced carcinogenesis. Oral administration of caffeine has also been associated with in-vivo upregulation of tumor suppressor genes.14     Continued research revealed that topical application of caffeine inhibits carcinogenesis and promotes apoptosis in sunburn cells of hairless SKH-1, UVB-pretreated mice.15 Researchers found that topical application of the tea constituents caffeine and (-)-epigallocatechin gallate (EGCG) decreased the number of nonmalignant and malignant skin tumors in SKH-1 hairless mice pretreated with UVB. While caffeine performed better than EGCG, both treatments resulted in elevated apoptosis in nonmalignant skin tumors and squamous cell carcinomas. The results suggest a need for further studies to determine whether topical applications of caffeine or EGCG can inhibit sunlight-induced skin cancer in humans. Further studies by the same authors found that topical application of caffeine sodium benzoate and caffeine have both a sunscreen effect and enhance UVB-induced apoptosis and may be good agents for inhibiting the formation of sunlight-induced skin cancer.16     These studies present a potential use for caffeine in formulations used to decrease the risk of skin cancer formation after cutaneous damage from UV exposure. More studies need to be done to further examine caffeine's antioxidant potential. The above findings have prompted many manufacturers to add this popular agent to various cosmeceutical products on the market today (see Table 4).     Coffeeberry, harvested from the fruit of the coffee plant Coffea arabica, is considered to be one of the richest sources of antioxidants and is well known for its skin-rejuvenation properties. Coffeeberry contains potent polyphenols including chlorogenic acid, ferrulic acid, quinic acid, and condensed proanthocyanidins. The dermatologic application of CoffeeBerry? (J&J Technologies LC) extract was first recognized at the American Academy of Dermatology's Annual Meeting in February 2007. The first product to enter the market with CoffeeBerry as the basic ingredient is RevaléSkin (Stiefel Laboratories, Inc., Coral Gables, Florida) (see Table 5).     According to Stiefel Laboratories, Inc., CoffeeBerry has demonstrated high antioxidant properties, outperforming green tea extract and vitamins C and E. Proprietary research from the manufacturer has also shown that the use of the RevaléSkin CoffeeBerry skin care system consisting of 0.1% CoffeeBerry cleanser and 1% day and night creams showed statistically significant improvement in fine lines, wrinkles, pigmentation, and overall appearance when compared to vehicle. In addition to the evidence of safety and efficacy provided by the randomized, double-blind trials, further support comes from positive pathologic and in-vitro studies showing enhanced collagen production by fibroblasts. Studies are currently in progress to evaluate the use of the CoffeeBerry skin care system in conjunction with retinoids and intense pulsed-light treatments.17 More clinical studies need to be performed to fully assess the topical preparations containing CoffeeBerry extract, but polyphenols have already demonstrated efficacy in photoaging and skin cancer prevention.     The inclusion of botanical animal remedy additives in skin care products is becoming ever more popular. Potential antioxidant and anti-inflammatory benefits may prove beneficial for a number of conditions that dermatologists routinely treat, such as rosacea, photoaging, and skin cancer. The published effectiveness of prescription retinoids is well known, but equally well known is the irritation and redness often caused by the initiation of therapy. Botanicals may hold the promise of utility to reduce such inflammation. This is one of the best and most practical reasons to include botanicals in skin care protocols. Dermatologists should be aware of these products and be able to discuss their uses and potential benefits with their patients.

Fecha de Publicación: 09-10-21

Pipe Fittings

Descripción:     Pipe Fittings     This chapter presents various types of pipe fittings. Of all the fittings, the elbow is the one most often used. Simply put, the elbow, or ell, is used when a pipe changes direction. Elbows can turn up, down, left, right, or any angle in between. When one finds it necessary to draw a 90° elbow or calculate how much space it will occupy in a routing configuration, knowing its length becomes essential. An elbow's length is commonly referred to as the center-to-end dimension and is measured from the centerpoint of its radius to the end of either opening. Dimensional sizes of fittings are typically provided by the manufacturer of the fitting. Manufacturers issue dimensioning charts containing lengths for a particular fitting. Another elbow that may be used under certain circumstances and with permission from the customer is the 90° short-radius elbow. The 90° short-radius ell makes a much sharper turn than does the long-radius ell.     Emissions from Pipe Fittings and Gaskets     Threaded pipe fittings in the seal flush line can be significant leak sources, with readings above 1,000 ppm.4,17 Similar emission levels may be measured near the gasket region on the seal chamber face. Any leakage from these areas may drift into the emission measurement area for the mechanical seal. The mechanical seal may then be erroneously implicated as a leaker. It should be standard practice to sniff nearby hydraulic fittings and the flange gasket area if excessive VOC concentrations are detected adjacent to the mechanical seal.     Leak-tight threaded pipe fittings can be more easily attained using anaerobic paste-type sealants rather than PTFE tape. The seal chamber face must be smooth to be emission tight. Gaskets and O-rings must be free of nicks and scratches.     32.16.2 Thermoplastic Fittings Manufacturing     Thermoplastic pipe fittings may be injection-molded, fabricated, rotomolded, or thermoformed. Injection-molded fittings are generally made in sizes through 12-in. nominal diameter. Typical molded fittings are tees, 45-degree and 90-degree elbows, reducers, couplings, caps, flange adapters, stub ends, branch saddles, service saddles, and self-tapping saddle tees. Electrofusion couplings and fittings are either made by injection molding or machined from pipe stock. Electrofusion fittings and couplings are made with a coil-like integral heating element incorporated into the fitting. Joining with other fittings uses an electrical fusion device that provides electricity into the heating element, which melts the adjacent thermoplastic material and creates a fusion-welded joint.     Larger-diameter fittings exceed the capabilities of injection molding and are typically fabricated. Rotomolding is used for the manufacture of polyethylene large-diameter (up to 60 in.) and custom fittings for polyethylene corrugated drainage piping applications.     Thermoformed fittings are made by heating a section of pipe and then using a forming tool to reshape the heated area. Examples of thermoformed fittings are sweep elbows, swaged reducers, and forged stub ends. Some polyethylene corrugated pipe fittings and appurtenances are also thermoformed.     All proprietary joints shall be made in accordance with the manufacturer’s instructions. Care shall be taken to establish satisfactory jointing techniques for all water service pipework. When making joints by welding, brazing, or soldering, precautions shall be taken to avoid the risk of fire. All burrs shall be removed from the ends of pipes and any jointing materials used shall be prevented from entering the waterways. All piping and fittings shall be cleaned internally and free from particles of sand, soil, metal filings, and chips, etc.     8.19.3 Cast iron pipes     Flexible mechanical joints shall be made in accordance with the manufacturer’s instructions.     For molten lead joints, the spigot and socket shall be centered with rings of dry yarn caulked tightly into the bottom of the spigot to prevent the entry of lead into the bore of the pipe and to prevent contact of lead with the water.     Synthetic yarns that do not promote the growth of bacteria shall be used to prevent contamination of the water. The remainder of the joint space shall be filled with molten lead (taking care that no dross enters the joint), cold wire, strip, or spun lead (lead wool). The joint shall be caulked to a smooth finish with pneumatic tools or a hand hammer of mass not less than 1.5 kg. When working with spun lead, caulking tools shall be of a thickness to fill the joint space, ensuring thorough consolidation of the material to the full depth of the socket.     Lead joints shall be finished about 3 mm inside the face of the socket.     Flange joints shall be made with screwed or cast on flanges.     8.19.4 Steel pipes     Welded joints shall not be used where a protective lining would be damaged by heat, or where the pipework is employed as a primary circulation to an indirect hot water heating system.     Screwed joints in steel piping shall be made with screwed socket joints using wrought iron, steel, or malleable double crimping fitting. A thread filler shall be used. Exposed threads left after jointing shall be painted or, where installed underground, thickly coated with bituminous or other suitable corrosion preventative agent.     Flange joints shall be made with screwed or welded flanges of steel or cast iron using jointing rings and, if necessary, a suitable jointing paste. The nuts shall be carefully tightened, in opposite pairs, until the jointing ring is sufficiently compressed between the flanges for a watertight joint.     8.19.5 Unplasticized PVC pipes     8.19.5.1 Mechanical joints     Mechanical joints in unplasticized PVC piping of sizes 2 and upwards shall be made in accordance with BS4346: Part 2, by the use of push-fit integral elastomeric sealing rings which are compressed when the plain ended pipes are inserted into the adjoining sockets. The plain pipe ends shall be chamfered and the surfaces cleaned and lubricated.     The chamfered pipe end shall be inserted fully into the adjoining socket (except where provision is to be made for expansion), or as far as any locating mark put on the spigot end by the manufacturer. The sealing rings shall comply with BS2494.     8.19.5.2 Compression joints     Compression joints shall only be used with unplasticized PVC piping of size 2 and smaller. The joints shall be of the nonmanipulative type. Care shall be taken to avoid overtightening.     8.19.5.3 Solvent cement welded joints     Solvent cement welded joints in unplasticized PVC piping shall be made using solvent cement complying with BS4346: Part 3 recommended by the manufacturer of the pipe. The dimensions of the spigots and sockets shall comply with BSEN1452: Part 1–5.     Joints may also be made using integral sockets formed in the pipes and solvent cemented.     8.19.5.4 Flanged joints     Flanged joints used for connections to valves and fittings shall use full-face flanges or stub flanges, both with corrosion resistant or immune backing rings and bolting.     8.19.5.5 Polyethylene pipes     Mechanical joints shall be either plastics or metal proprietary compression fittings, for example, brass, gunmetal, or malleable iron. These shall include insert liners to support the bore of the pipe except where the manufacturer of the fitting instructs otherwise.     To ensure satisfactory jointing of the materials from which the pipe and transition elbow are made compatibility shall be established. The manufacturer’s instructions shall be carefully followed.     No attempt shall be made to joint polyethylene piping by solvent cement welding.     Large pipe fittings and valve components must be press forged and will require extensive machining. Whereas small parts such as the flange previously described can be quickly heated and cooled, and given optimum process conditions, should exhibit microstructure and properties similar to pipe and tube, the properties of large forgings will be location and thickness dependent. While no large forged part has yet been made from 740H, the properties of a solution-annealed, water-quenched and aged 343-mm-diameter bar shown in Table 14.2 are informative. Yield strength near the surface is comparable to that of thin wall tube, but yield strength at the bar center, while meeting ASME minimum, is significantly lower. Ductility and toughness were good. A hardness traverse taken on the as quenched bar showed VHN 170 at the surface and VHN 290 at the center. This is indicative of strong auto-aging in the bar center. Because the γ′ that forms on slow cooling is relatively coarse, after the final aging treatment, the bar center will have lower strength than the surface. The microstructure and creep strength at the center of the bar has not been evaluated.     A calculated continuous cooling transformation diagram for alloy 740H is shown in Fig. 14.26. This diagram supports the notion that significant γ′ hardening will occur even during water quenching of a large forging. A cooling simulation was conducted for the bar heat treatment using DEFORM software . The cooling rate at a depth of 25 mm was 315°C/min and at the bar center was 30°C/min. Based on the calculated CCT diagram, there should be about 10% γ′ in the center and no γ′ at the surface. That is consistent with the experimental results.     Filament-wound pipe fittings, such as elbows and tees have been used in the chemical, and oil industry since the 1980s.9 Traditionally, composite pipe fittings were produced manually or semi-manually, but the development of CNC winders with six or more axes has allowed automated production of pipe fittings since the 1990s. The efficiency of these advanced machines depends on methods and software to determine winding patterns and perform fabrication of the complex shape within manufacturing specifications. Winding pattern generation is particularly challenging since a substantial amount of data storage/processing is required to meet manufacturing requirements (e.g., fiber tension and full-coverage) of non-axisymmetric patterns, which are required for filament-wound elbows or tees.72 On the other hand, it is worth noting that CAM software capability, rather than hardware, is considered the limiting factor for improving the performance of automated winders of non-axisymmetric parts. Consequently, general-purpose filament winding systems for pipe fittings are currently deemed impractical due to the lack of universal mathematical models and design software for CAM.9,73 Although some progress has been made to determine closed-form solutions for efficient winding patterns on specific shapes, such as elbows,74,75 most CAM systems still implement approximate methods to design and produce specific pipe fitting geometries.73 An illustration of a software-generated winding pattern, and the resulting wound elbow, is included in Fig. 11.75     Leaking valves and pipe fittings are the next concern when pressure is dropping during a test. Test sections should be isolated at pipeline block valves by using slip blinds to insure no leakage. If the test section cannot be blinded but the valves are double blocked instead, the operator must measure pressure increase in the adjacent section between the double-blocked valves to insure a tight seal exists. You need to be careful when using a thin “fire blind” at an isolation valve because under pressure the thin blind will deform and the blind cannot be removed without removing the entire valve. This often requires calling in vacuum trucks to remove product on the opposite side of the test valve being removed.     So, leakage through valves and fittings jeopardizes the chances for a successful test and may lead to data that cannot be correlated, and in that situation, the pipeline must be retested.     Tree piping is defined as all pipe, fittings, or pressure conduits, excluding valves and chokes, from the vertical bores of the tree to the flowline connections. The piping may be used for production, pigging, monitoring, injection, servicing, or testing of the subsea tree. Inboard tree piping is upstream of the first tree wing valves. Outboard tree piping is downstream of the first tree wing valve and upstream of the flowline connector.     Tree piping is normally designed in accordance with ASME B31.3. The guidelines in the API specifications are general and, in many cases, open to interpretation. It is up to the manufacturer to apply his engineering judgment.    

Fecha de Publicación: 09-10-21

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