- Created: 29-08-21
- Last Login: 29-08-21
Description: Types of Hourglass Before the invention of mechanical clocks, timepieces used the sun's motion or simple measurement devices to track time. The sundial may be the best known ancient keeper of time, and it is still manufactured as a popular garden accessory—but for its visual interest, not for practical time measurement. Stonehenge, the giant monument built of upright stones on the Salisbury Plain of Wiltshire, England, may have been used as a sundial and for other time and calendar purposes. Sundials have obvious disadvantages; they can't be used indoors, at night, or on cloudy days. Other simple measurement devices were used to mark the duration of time. Four basic types could be used indoors and regardless of the weather or time of day. The candle clock is a candle with lines drawn around it to mark units of time, usually hours. By observing how much of the length of a candle burned in one hour, a candle made of the same material was marked with lines showing one-hour intervals. An eight-hour candle showed that four hours had passed when it had burned down beyond four marks. The clock candle had the disadvantages that any changes in the wick or wax would alter burning properties, and it was highly subject to drafts. The Chinese also used a kind of candle clock with threads used to mark the time intervals. As the candle burned, the threads with metal balls on their ends fell so those in the room could hear the passage of the hours as the balls pinged on the tray holding the candle. The oil lamp clock that was used through the eighteenth century was a variation and improvement on the candle clock. The oil lamp clock had divisions marked on a metal mount that encircled the glass reservoir containing the oil. As the level of oil fell in the reservoir, the passage of time was read from the markings on the mount. Like the candle clock, the oil lamp clock also provided light, but it was less prone to inaccuracies in materials or those caused by drafty rooms. Water clocks were also used to mark the passage of time by allowing water to drip from one container into another. The marks of the sun's motion were made on the first container, and, as water dripped out of it and into another basin, the drop in water level showed the passage of the hours. The second container was not always used to collect and recycle the water; some water clocks simply allowed the water to drip on the ground. When the eight-hour water clock was empty, eight hours had passed. The water clock is also known as the clepsydra. History Sand timer hourglass (also called sand glasses and sand clocks) may have been used by the ancient Greeks and Romans, but history can only document the fact that both cultures had the technology to make the glass. The first claims to sand glasses are credited to the Greeks in the third century B.C. History also suggests sand clocks were used in the Senate of ancient Rome to time speeches, and the hourglasses got smaller and smaller, possibly as an indication of the quality of the political speeches. The hourglass first appeared in Europe in the eighth century, and may have been made by Luitprand, a monk at the cathedral in Chartres, France. By the early fourteenth century, the sand glass was used commonly in Italy. It appears to have been widely used throughout Western Europe from that time through 1500. The hourglass or sand clock follows exactly the same principle as the clepsydra. Two globes (also called phials or ampules) of glass are connected by a narrow throat so that sand (with relatively uniform grain size) flows from the upper globe to the lower. Hourglasses were made in different sizes based on pre-tested measurements of sand flow in different sizes of globes. A housing or frame that enclosed the globes could be fitted to the two globes to form a top and bottom for the metal sand timer and was used to invert the hourglass and start the flow of sand again. Some hourglasses or sets of hourglasses were set in a pivoted mount so they could be turned easily. The earliest writings referring to sand glasses are from 1345 when Thomas de Stetsham, a clerk on a ship called La George in the service of King Edward III (1312-1377) of England, ordered 16 hourglasses. In 1380, following the death of King Charles V (1337-1380) of France, an inventory of his possessions included a "large sea clock … in a large wooden brass-bound case." John Harrison and his brother James were introduced to clock repair by their father, Henry. At the time, clock making, or horology, was undergoing a developmental revolution. Mechanical clocks had existed since the fourteenth century, but had remained rather primitive in their operation until Christiaan Huygens invented the weight-and-pendulum clock in 1656. One limitation was that they were totally dependent upon the earth's gravity for their operation. This meant that they could not keep accurate time at sea, and could not be adapted for portability. Even moving them across a room would require adjustment. The Harrison brothers set to work on developing a marine chronometer in 1728. The motivating factor was money. In 1714, the English Admiralty set up an award of ￡20,000 for anyone who could provide mariners with a reliable clock that, when used with celestial sightings, could keep them informed of their longitude at sea. Mariners had to rely heavily on dead reckoning to find their way, often leading to tragic results. The Harrison strategy was to design an instrument that was not only internally accurate but also externally stable. The Harrisons made several models of marine chronometers. The fourth model proved to be the most successful. On a nine-week voyage from England to Jamaica in 1761, the device had only a five-second error. The Board of Longitude, apparently miffed that a common artisan had achieved the coveted goal, reluctantly gave up only half of the prize. John, minus his brother, refused to accept only half of the reward and persisted until the other half was relinquished. The Board subjected his invention to undue scrutiny and required him to design a fifth model. This time, Harrison outdid himself by designing a compact timepiece that resembled a modern day pocket watch. It was far more convenient than the previous models, which were heavy and bulky. The Board still refused to capitulate. Finally, only a personal appeal to King George III and the King's intervention could set things right, and Harrison received the full reward in 1773 at age seventy-nine. Harrison lived only three more years. These two early associations of sand clocks with the sea show how navigation had become a time-dependent science. Compasses and charts, developed in the eleventh and twelfth centuries, helped navigators determine bearings and direction, but time measurement was essential to estimating distance traveled. The sand glass may have been invented —or perfected—for use at sea where equal units of time were measured to estimate distance; by contrast, on land, unequal time measurements were more important because activities depended on the length of day. The great advances in maritime science occurred in the twelfth century with the development of the magnetic compass in Amalfi, Italy. Other Italian port cities like Genoa and Venice contributed to the astronomical advances in navigation, and, by coincidence, Venice was the world's greatest glass-blowing center. Furthermore, the fine marble dust from the quarries at Carrara was perfect for use as sand in navigational sand clocks. As well as measuring time as distance at sea, hourglasses were used by the navies of several nations to "keep the watch" or measure the time the crew worked. The ship's boy was in charge of turning the hourglass; to get off work early, he would "swallow the sand" or turn the glass before it was empty. The most extraordinary hourglasses were made as gifts for royalty. Charlemagne (742-814) of France possessed a 12-hour hourglass. In the sixteenth century, Holbein (1497-1543) the artist made spectacular hourglasses for Henry VIII (1491-1547) of England. Other sand glasses contained multiple instruments. For example, a sand glass made in Italy in the seventeenth century contained four glasses. One had one-quarter hour of sand; the second, a half-hour of sand; the third, three-quarters of an hour of sand; and the fourth contained the full hour's measure of sand. Some glasses also had dials with pointers, so, with each turning of the glass, the number of turns could be shown with the pointer to mark the cumulative passage of time. The upper and lower globes of each glass were blown separately with open apertures or throats. To join them so that sand could flow from the upper globe to the lower, the two halves of the glass were bound together with cord that was then coated with wax. The two-coned glass phial could not be blown as one piece until about 1800. In about 1500, the first clocks began to appear with the invention of the coiled spring or mainspring. Some weight-powered clocks had been made before 1500, but their size limited their practicality. As the mainspring was improved, smaller, tabletop clocks were manufactured and the first watches were made. Mainspring-driven clocks made curiosities out of clepsydras and sand glasses, but, interestingly, the most beautiful hourglasses were made after 1500 as decorative pieces. There are many types of hourglasses, such as metal hourglass，wood hourglass and so on. By the 1400s, many private homes had sand clocks for household and kitchen use. Sermonglasses were used in churches to track the length of the minister's sermon. Hourglasses were also routinely used in the lecture halls of Oxford University, craftsmen's shops (to regulate working hours), and in England's House of Commons where bells to signal voting and lengths of speeches were timed based on sand clocks. During the height of the sand glass, doctors, apothecaries, and other medical practitioners carried miniature or pocket sand glasses with durations of one-half or one minute to use when timing pulses; the practice of carrying these continued until the nineteenth century. Today, miniature versions containing three minutes worth of sand are sold as egg timers and as travel souvenirs. Larger sand clocks are still made today of ornamental materials and in interesting styles for use as decoration. All of these measuring devices (clock candles, water clocks, and sand clocks) have the disadvantage that they must be watched carefully. How to use a massage ball Like a foam roller, a massage ball can also be used to help release tension in our achy muscles after long hours spent in the office or after a workout. One of the differences being that it can get to those hard to reach areas such as the upper back, buttocks and feet. “Knots” or “trigger points” can be massive sources of pain in our bodies and using self-massage techniques can be very satisfying. Before diving in, there are a few important things to know which will help you achieve the best results. Why a massage ball Massage balls are affordable and small and therefore they can easily fit into a suitcase or handbag to use wherever you go. They also promote self-sufficiency so there is no need to rely on anyone else. Notwithstanding, it does not always give the same results as a traditional massage delivered by an experienced therapist Find the right ball There are many different types of massage balls ranging from very smooth and firm like a lacrosse ball to small and soft like a squash ball. Other balls include a tennis ball and the trusty spikey massage ball. To each his own but if you’re new to using a massage ball, perhaps start with a spikey ball or a tennis ball. Where and when Since they are so conveniently easy to use, you can use them almost anywhere for example against a wall, the back of a chair, on the floor or use your hands. Some office workers keep them at their desks as a reminder to use them during the day to help with releasing built-up muscle tension from poor posture or stress. Start with only a few knots at a time, the most painful area being first. The idea is to trap the knot in the muscle with the ball and apply gently to medium pressure until the painful sensation has faded. Once you have the correct spot (and you will know when), hold it there and try to relax until only about 80% of the ache remains. When pressing too firmly, the sensation can be too painful for you to relax which defeats the purpose of using the massage ball in the first place, it could also potentially irritate the area. You are looking for a “good pain”.Roll the ball around to look for more tender spots or just enjoy gently going back and forth over the tight muscle. If you feel the muscle needs it, you can repeat it twice a day. After releasing the knot, follow it up with gentle stretches to the same muscle. It’s okay to lightly exercise the muscle afterward but avoid fatiguing it for 24 hours. The gear shift knob in a manual transmission equipped car or light truck is the large knob, usually made of plastic, that attaches to the top of the gear shift lever. Over time the surface of the knob can wear and you might wish to replace it to spruce up the interior of your vehicle. Many aftermarket manufactures offer specialty gear shift knobs. Some of these are made out of exotic materials such as leather or billet aluminum. Some companies offer novelty gear shift knobs for owners who want to personalize the interiors of their vehicles.
Publish Date: 29-08-21
Description: Ball Valve - How They Work A ball valve is a shut off valve that controls the flow of a liquid or gas by means of a rotary ball having a bore. By rotating the ball a quarter turn (90 degrees) around its axis, the medium can flow through or is blocked. They are characterized by a long service life and provide a reliable sealing over the life span, even when the valve is not in use for a long time. As a result, they are more popular as a shut off valve then for example the gate valve. For a complete comparison, read our gate valve vs ball valve article. Moreover, they are more resistant against contaminated media than most other types of valves. In special versions, ball valves are also used as a control valve. This application is less common due to the relatively limited accuracy of controlling the flow rate in comparison with other types of control valves. However, the valve also offers some advantages here. For example, it still ensures a reliable sealing, even in the case of dirty media. Figure 1 shows a sectional view of a ball valve. Standard (threaded) Standard ball valves consist of the housing, seats, ball and lever for ball rotation. They include valves with two, three and four ports which can be female or male threaded or a combination of those. Threaded valves are most common and come in many varieties: with approvals for specific media or applications, mini ball valves, angled ball valves, ISO-top ball valves, with an integrated strainer or a bleed point and the list goes on. They have a wide range of options and a large operating range for pressure and temperature. For more information on a threaded connection, read our ball valve connection types article. Hydraulic Hydraulic ball valves are specially designed for hydraulic and heating systems due to their high operating pressure rating and hydraulic and heating oil resistance. These valves are made of either steel or stainless steel. Besides these materials, the seats also make hydraulic valves suitable for high operating pressure. The seats of these valves are made of polyoxymethylene (POM), which is suitable for high pressure and low temperature applications. The maximum operating pressure of hydraulic ball valves goes above 500 bar while the maximum temperature goes up to 80°C. Ball valves are used for both on/off and throttling service. Ball valves are similar to plug valves but use a ball-shaped seating element (Figure 4.56). They are quick-opening and require only a quarter-turn to open or close. They require manual or power operators in large sizes and at high operating pressures to overcome the operating torque. They are equipped with soft seats that conform readily to the surface of the ball and have a metal-to-meal secondary seal. If the valve is left partially open for an extended period under a high pressure drop across the ball, the soft seat may become damaged and may lock the ball in position. Ball valves are best suited for stopping and starting flow but may be used for moderate throttling. Compared with other valves with similar ratings, ball valves are relatively small and light. Flanged Flanged ball valves are characterized by their connection type. The ports are connected to a piping system via flanges that are usually designed in accordance with a certain standard. These valves provide a high flow rate since they typically have a full-bore design. When choosing a flanged ball valve, besides the pressure rating, you also have to check the flange compression class which indicates the highest pressure this connection type can withstand. These ball valves are designed with two, three or four ports, they can be approved for specific media, have an ISO-top and everything else a standard quarter turn valve could have. They are typically made out of stainless steel, steel, or cast iron. Vented Vented ball valves look almost the same as the standard 2-way ball valves when it comes to their design. The main difference is that the outlet port vents to the environment in closed position. This is achieved by a small hole that is drilled in the ball and in the valve body. When the valve closes, the holes line up with the outlet port and release the pressure. This is especially useful in compressed air systems where depressurization provides a safer working environment. Intuitively these valves look like 2-way ball valves while in fact they are 3/2-way due to the small borehole for venting. Ball valves are not recommended for FO applications. Generally, it is possible to reduce the opening time of the fail open actuated valve by installing a quick exhaust valve on the control panel to release the instrument air from the pneumatic actuator in the fail mode quickly. However, a ball valve’s seat and disk are in contact during the opening and closing, which can jeopardize FO. In addition, moving the relatively large and heavy ball requires a higher stem torque, a larger actuator, and perhaps a longer opening time. The ball valve manufacturer was asked about the possibility of using a soft seat ball valve for this application. The manufacturer believed that FO of the soft seat ball valve in 2 s could cause damage to the soft seat because of the very quick contact with the ball. On the other hand, the manufacturer stated that a 2-s opening time can be achieved with a metal seat ball valve. But a metal seat has the disadvantage of possible leakage, unlike a soft seat, and it is a more costly solution than butterfly and axial control valves due to the valve and the large mounted actuator. Unlike FO applications, a ball valve is a good choice as a blowdown valve with less opening time than an FO valve. Fig. 12.25 shows a blowdown ball valve to release the overpressured fluid from the equipment in an emergency mode. The blowdown ball valve is an 18″ Class 2500 in a 6MO body and a metallic Inconel 625 seat, which may need 18 s for opening. Blowdown or FO valves on flare lines usually see low operating temperatures because of the released gas pressure drop. Gas pressure drop reduces the operating temperature to ? 46°C or even lower, so the minimum design temperature is typically below ? 100°C. The low temperature application makes it impractical to use 22Cr duplex with a minimum design temperature of ? 46°C for the valve, so 6MO or Inconel 625 are the correct choices of materials. An extended bonnet is used for the valve to keep the packing away from the relatively cold service, similar to cryogenic valves. Ball valve working principle To understand the working principle of a ball valve, it is important to know the 5 main ball valve parts and 2 different operation types. The 5 main components can be seen in the ball valve diagram in Figure 2. The valve stem (1) is connected to the ball (4) and is either manually operated or automatically operated (electrically or pneumatically). The ball is supported and sealed by the ball valve seat (5) and their are o-rings (2) around the valve stem. All are inside the valve housing (3). The ball has a bore through it, as seen in the sectional view in Figure 1. When the valve stem is turned a quarter-turn the bore is either open to the flow allowing media to flow through or closed to prevent media flow. The valve's circuit function, housing assembly, ball design, and operation types all impact the ball valve's operation are are discussed below.Circuit function The valve may have two, three or even four ports (2-way, 3-way or 4-way). The vast majority of ball valves are 2-way and manually operated with a lever. The lever is in line with pipe when the valve is opened. In closed position, the handle is perpendicular to the pipe. The ball valve flow direction is simply from the input to the output for a 2-way valve. Manually operated ball valves can be quickly closed and therefore there is a risk of water hammer with fast-flowing media. Some ball valves are fitted with a transmission. The 3-way valves have an L-shaped or T-shaped bore, which affect the circuit function (flow direction). This can be seen in Figure 3. As a result, various circuit functions can be achieved such as distributing or mixing flows. Inspecting Pipes in Exterior Walls and Pipe Insulation Locating water pipes in exterior walls should be avoided. If pipes are located in exterior walls, in addition to insulating the pipe, the homeowner should ensure that as much cavity insulation as possible is installed between the pipe and the outer surface of the wall. In cold climates, having pipes in unconditioned attics should be avoided. The image above is of uninsulated water supply pipes in an unconditioned basement. Insulating water pipes can save energy by minimizing heat loss through the piping. Insulating pipes will reduce the risk of condensation forming on the pipes, which can lead to mold and moisture damage. Insulation pipe can protect the pipes from freezing and cracking in the winter, which can cause considerable damage in the walls of the home and result in significant home repair bills for the homeowner. Studies by the Department of Energy (DOE’s) Building America program have shown that distribution heat loss in uninsulated hot water pipes can range from 16% to 23%, depending on the climate. Adding 3/4-inch pipe insulation can cut overall water heating energy use by 4% to 5% annually. The best practice is to avoid having water pipes located in exterior walls or through unheated attics. It is preferable to have plumbing fixtures aligned with interior walls. If pipes are located in exterior walls, the pipes should be insulated. To further protect the pipes from heat loss, the wall cavity containing the pipes should be air-sealed by caulking or foaming all seams between the back wall of the cavity and the framing, and by sealing any holes through the framing for the piping. In addition, cavity insulation should be installed behind the pipes, between the pipes and the exterior wall. If the house has a hydronic (steam or hot water) heating system, heat loss can be reduced by as much as 90% by insulating the steam distribution and return pipes, which provides a quick payback on investment. Insulated copper coil is one of the main aspects of many of Joseph Henry’s experiments in the field of Electricity and Magnetism is the large coils or helices of copper wire or ribbon he used. These coils were often quite large, usually containing over 1000ft of wire and sometimes weighing over 10lbs. As described by Henry in his papers, these coils were often insulated by wrapping the wires in cotton, dipping them in beeswax, and then painting. Optimization and intelligent manufacturing are of particular interest and important to improve the severe situation of excessive mass and uneven stress distribution for three branch joint in treelike structures. In this work, the optimal shape of the three-branch joints under vertical load is studied by topology optimization method, and the complex topology optimization Y joint is manufactured using threedimensional (3D) printing technology because it is difficult to produce by conventional manufacturing processes. First, the original model is optimized by using the OptiStruct solver in HyperWorks version 14.0 (64-bit) software, and the element density cloud map and element isosurface map of the model are obtained. Then, the static behaviors of the topology optimization model are compared with those of the hollow spherical joint model which is commonly used in engineering and those of the bionic joint model based on empirical design. Finally, the 3D printing technology is used to produce the topology optimization joint model, the hollow spherical joint model, and the bionic joint model.
Publish Date: 29-08-21
Description: 5 Reasons to Select Paving Stones Over Concrete The walkway or drive that leads to your home should be both a personal statement and a reflection of your good taste. What’s more, the materials should stand up to the weather, look great for years at a time and not be a burden with costly, involved maintenance. Concrete was the favored material for years because it met some of these criteria. But today paving stones are the clear choice. Here are five reasons why: 1. Stains and other imperfections can be easily hidden with pavers If you splash a little oil on a concrete drive, the stain usually becomes an ugly, permanent blemish. Not so with pavers. These can be quickly flipped or replaced so you always have a surface that looks pristine. 2. Pavers come in a wide range of attractive colors and designs Mixing and matching all the possible different combinations will give you a unique drive or patio every time. The different ways you can put paving stones together are limited only by your imagination. 3. A paver walkway is ready to go from the time it's installed Unlike concrete, which can take three to five days before it’s ready for traffic, there’s no curing period with pavers — and no waiting. 4. It's easier to make adjustments with pavers When a concrete base shifts, cracking can result in costly repairs that are visible even when they’ve been professionally done. It’s much easier to deal with a paver’s base that has moved. Just remove the stones over the affected area, level if needed, then replace the same pavers for a finish that looks as good as new. 5. Better drainage means a secure paver surface Pavers are solid under your feet. Because of all the joints between paving stones, rain drains away much more easily than it does from flat concrete surfaces. This feature makes pavers much more slip-resistant. Upgrading to pavers is the right choice for several reasons. This is a durable, worry-free material that will last for years. Use Paving Stones to Transform Your Outdoor Space If you find yourself gazing out into your backyard thinking of something you can do to spruce things up, have you considered using paving stones? Installing them is not difficult, and depending on the size of your project, it can be completed in as quickly as one weekend. The concept of using paving stones has been around as long as civilization --and for good reason. It is a simple, tried-and-true choice for builders who want attractive, durable results using simple tools and materials. Few projects can be accomplished so quickly and last as long. Paving stones are versatile enough to suit jobs of any size or type. Regardless of your project: A simple walkway, a flower garden, a patio with barbeque, or even a driveway --paving stones are ideal. Below are some things to think about before starting your paving stone project: Find inspiration Do you already have an idea of what you want? If not, there are plenty of places to find inspiration. View landscaper’s websites and browse their galleries to see what is possible with paving stones. Of course there are always magazines as well. You may find new ideas that you weren’t aware of before you began your search. Study your yard Consider your needs and your space limitations. Can you fit your idea into the space you have? Take into consideration proximity to structure and trees. A small tree today may be a big problem in the future as the root system grows. Types of stones Are paving stones and stone pavers the same thing? Sort of. Paving stones (also referred to as pavers) are not necessarily made from naturally occurring stone. They are often cast from man-made materials like bricks. Some are cut from natural stone and therefore are called stone pavers. Besides a limitless number of colors, there are different types of pavers, such as brick, concrete, natural stone and even rubber. Most man-made pavers are also available in interlocking shapes. Draw a picture A piece of graph paper can be a great help. Draw out your plan, scaling each square as one foot (or other easily converted unit of measure). Color the bricks if you are planning to make a pattern with your stones. Using graph paper makes it easier to count how many stones of each color will be needed. Unlike a deck, the maintenance for a stone patio is a snap. They are modular in nature, so it is also easy to move them around as your landscaping needs change. Also, have you ever stepped barefoot onto your deck after it’s been in the sun all day? Pavers are cooler on your feet. Finally, pavers won’t crack like concrete can. If planned and installed properly, you’ll be ready for the summer simply by sweeping your patio and bringing out your furniture! How to design a fireplace with cultured stone When searching for an easy and cost effective design solution for a fireplace, cultured stone or manufactured stone veneer should definitely be considered. There are a variety of patterns and colors to choose from, and a multitude of ways to enhance any interior space. Culture stones are a cost-effective way to add nature-inspired beauty to any indoor fireplace. This ledgestone fireplace (left) was built in Parkland, FL. The fireplace was framed with drywall and had a wooden shelf with a large mirror in the center. The floor-to-ceiling fireplace with cultured stones is very interesting, visually. The manufacturer’s recommendation is to install wire lath on top of the drywall with a scratch-coat of mortar; however, you should simplify this step and use backer boards instead. These provide the proper adhesion and save a considerable amount of labor. After the installation of the backer boards, apply bonding agent on the area getting stoned. Cultured stones, also called manufactured stones, can be rustic or refined. If you wish to install cultured stones on your own I would advise that you lay out a selection of different stone sizes on the ground. This will make it easier to find the right size and achieve the best blend in color. Always mix different sizes of stones. Also, alternate or stagger the joints create a pattern that is pleasing to your eyes. A good rule of thumb is to break up the vertical and horizontal joints as often as possible. Even as Central Delhi begins the kerb stone makeover — paint them saffron and green — the decision, taken by the New Delhi Municipal Council, has come under severe criticism from several quarters, including the traffic police and an NDMC member herself. Further, the use of regular paints, as opposed to the retro-reflective thermoplastic variety, is considered to violate road rules. Kerb stones are placed on roads as markers of danger. They are usually painted in ‘black and white’ or ‘black and yellow’. The NDMC had touted the move as an “aesthetic initiative” which would “bring uniformity to the area”. According to Indian Road Congress, the national body of technical highway engineers, “yellow, white and black are the standard colours used for markings”. The same is stated by the Unified Traffic and Transportation Infrastructure (Planning and Engineering) Centre and International Vienna Convention on Road Signs and Signals, of which India is a ratified member. Granite Paving Stones Rise in Popularity Granite paving stones are quickly becoming the “it” hardscape item of the year as more projects seek a product that’s cost effective, unique, and durable. Add those keys to a versatile product for both residential and commercial projects and it's no wonder they are becoming more popular. Paving stones (commonly referred to as "pavers") are typically made from one of three materials: natural stone, brick, or cement. Each one of these provides a different look and feel to a specific project and have their own pros and cons. 4 Reasons Granite Paving Stones Are Trending Compared to this time last year our sales of natural stone flagging and pavers are up more than 300%. The majority have been granite but a small percentage includes a schist and quartzite and it does not include bluestone. It’s exciting for us to see this growth and when we see a trend like this we look to focus on the “why”. Sustainability: Natural stone products are natural and durable with minimal carbon footprint. The majority of our stone is from local quarries and our process involves breaking or cutting stone down to size so no chemicals are used in the product. Natural stone is considered to be a "green" building material. Unique: We hear it on a regular basis, “I want something different”. No two pieces of natural stone are identical so when you lay down your granite pavers it’s going to be different than anything else out there. Even if your neighbor uses the same stone there will be variation. Quality: We used the word durable in our first point and natural stone, especially from New England, continues to stand the test of time and elements. Granite paving stone is durable which is why you can work with “reclaimed” granite. It’s stone and it’s built to last. Affordable & Available: Stone is heavy and for a long time was difficult to move or ship. Similar to the introduction of thin stone veneer, advancements in technology have made granite pavers more available, easier to transport, and help reduce the installation time, which saves money on the job. It' s exciting to see the growing trend in natural and granite paving stones and we expect to see it continue to increase in demand for the years to come.
Publish Date: 29-08-21
Description: Desuperheater Application Best Practices An ever-increasing need for steam at specific temperatures and pressures exists in many modern plants. Fortunately, significant improvements have been made to increase operational thermal efficiency and heat rates by the precise, coordinated control of the temperature, pressure and quality of this steam. But, much of the steam produced in power and process plants today is not at the required conditions for each application, so conditioning is required, often by a desuperheater system. The sizing, selection, application, installation and maintenance of the proper desuperheating and steam-conditioning equipment, including control valves, is therefore critical to optimum performance. This article will discuss superheaters and associated control valves in detail, but first I will look at common applications and issues in affected industries. Power Industry Competing in the modern power market requires a heavy emphasis on the ability to utilize multiple operating strategies. Increased cyclical operation, daily start-stop and faster ramp rates are required to ensure full-load operation, particularly at daily peak hours, and to maximize profit and plant availability. Changes resulting from environmental regulations and economics also are combining to alter the face of power production. At the same time, these changes are affecting the operation of existing power plants and the design of future plants. Advanced plant designs include requirements for increased operating temperatures and pressures along with stringent noise limitations in urban areas. Steam is used throughout power plants in many ways, from driving to turbines to feedwater heaters. Hydrocarbon and Petrochemical Industries Hydrocarbon and petrochemical industries rely on the efficient conversion of low cost feedstock to high profit products. Hydrocrackers, furnaces, distillation columns, reactors and other process units must be designed to meet a range of conditions to accommodate various modes of plant operation. Temperature is a critical factor that must be taken into consideration during the design of each process unit, and it must be controlled precisely to optimize each operation. Temperature is controlled in many ways in these plants. The most common method is through the use of heat exchangers and process steam. Process steam must be conditioned to a point near saturation before it is transformed into a medium that is more efficient for heat transfer. The proper selection of equipment will ensure optimum plant availability, reliability and profitability. Other process industries such as mining, pulp and paper, life sciences and food and beverage experience reliability issues caused by steam-conditioning challenges. These industries also use steam for motive force and heat transfer. Desuperheater Basics A schematic of a typical desuperheating system is shown in figure 1. A typical system consists of four main components: Control valve. Desuperheater. Temperature transmitters. Spray-water strainer. When specifying a desuperheater, it is advisable to consult with the manufacturer because most desuperheater suppliers have multiple models from which to choose. Critical parameters (figure 2) include: Spray-water temperature. Spray-water pressure. Initial steam superheat temperature. Final steam superheat temperature. Minimum steam velocity. Maximum steam velocity. Pipeline size. Downstream straight-pipe length. Steam-pipe liner. Orientation. While each components affects operation, a note on orientation is warranted. Orientation can affect the speed of vaporization. Horizontal installations are most common, but vertical flow-up installations perform slightly better because of the positive effect of gravity. Vertical flow-down pipes perform less efficiently because of the negative effect of gravity, which reduces residence time. Details of the actual control of a desuperheater are beyond the scope of this article; however, suffice it to say that pressure, temperature and flow sensors feed data to a control system that adjusts the spray-water control valve to deal with changing conditions. Control Valve Considerations When a desuperheating system is purchased, often each component will be specified and purchased separately. In other words, the desuperheater will be purchased from one vendor, the control valve from another and so on. Unless the process plant has an extensive expertise in the design of superheating systems — not often the case — this approach is problematic due to the complexity of these systems. The reasons are: There is generally a turndown specification for the system that needs to be met. The control valve has a turndown ratio, the desuperheater has a turndown ratio and the combination of the two has a completely different turndown ratio. Therefore, sizing and selection are critical to ensuring system performance is met. Different desuperheater designs will have different differential pressure (dP) requirements across the nozzles. The control valve differential pressure must be coordinated with the differential pressure across the desuperheater nozzles to ensure system performance is met. If there is a high differential pressure across the control valve — when a high pressure source is used to spray water into a low pressure steam line, for instance — cavitation can occur in the valve. The proper anti-cavitation trim must be installed in the control valve to suppress cavitation. If not, it is possible to have a cavitating pressure drop across the desuperheater nozzle, with catastrophic damage resulting, and potentially sending eroded desuperheater components into downstream equipment. A desuperheater nozzle has a specific flow coefficient (Cv). A control valve also has a range of flow coefficients based on its design. The flow coefficient for the valve and desuperheater must be matched so that overall system flow coefficient is optimized. It presents results in the thermal energy recovery system (TERS) investigation, and the possibility of introducing them to production vehicles as subsystems. This prospective new technology should reduce dependence on fossil fuels. One of the TERS systems' research objectives is to create a sustainable, electrical power source, suitable for the energy to be stored and later used in the electrical vehicle driving mode (EV)1. It will also lower the impact on the environment by reducing fuel consumption through the application of automotive thermoelectric generators (ATEG) instead of classical alternators that convert mechanical energy to electrical. Pressure reducer and desuperheater system (PRDS) is used for Steam Conditioning Services for reduction of pressure and temperature of steam. Suitably designed pressure reducing valve installed on superheated steam line, reduces steam pressure to desired operating pressure. The steam temperature is reduced close to saturation by injecting water into high velocity steam by controlled water flow through water control valve and often injected into the steam where steam velocity and turbulence are at their highest, which gives quick and efficient cooling. The purpose of this project is to optimize the Pressure reducing and desuperheating system to overcome the current losses such as valve leakage, gland leakage and header leakage.
Publish Date: 29-08-21
Description: Health Benefits of Peanuts Surprisingly, peanuts are not actually in the nut family. They are classified as legumes along with foods like green peas, soybeans, and lentils. The peanut plant likely originated in South America in Brazil or Peru. Scientists have found 3,500-year-old pottery in the shape of peanuts, as well as decorated with peanuts, in South America. Peanuts grow below ground as the fruit of the peanut plant. In the early 1800s, Americans started growing peanuts as a commercial crop. On average, Americans eat more than 6 pounds of peanuts per year. Today, 50% of the peanuts eaten in the United States are consumed in the form of peanut butter. Health Benefits Many people believe the peanut is not as nutritionally valuable as true nuts like almonds, walnuts, or cashews. But actually, raw peanuts have many of the same health benefits as the more expensive nuts and should not be overlooked as a nutritious food. Heart Health Much attention has been paid to walnuts and almonds as “heart-healthy” foods, given their high content of unsaturated fats. But research suggests that peanuts are every bit as good for heart health as more expensive nuts. Peanuts help prevent heart disease by lowering cholesterol levels. They can also stop small blood clots from forming and reduce your risk of having a heart attack or stroke. Weight Loss Foods with a lot of protein can help you feel full with fewer calories. And among nuts, peanuts are second only to almonds when it comes to protein count. Studies have shown that people who include a moderate amount of peanuts in their diet will not gain weight from peanuts. In fact, peanuts could help them lose weight. Longer Life Span Eating roasted peanuts might help you live longer too. A large-scale study found that people who regularly ate any kind of nuts (including peanuts) were less likely to die of any cause than were people who rarely ate nuts. Because the study was observational, it cannot prove that peanuts were exactly what caused the lower death rates, but they are definitely associated with them. How to Save Seeds 1. Know what to grow Start With Open-Pollinated Seeds Open pollinated varieties, aka OPs, are like dog breeds; they will retain their distinct characteristics as long as they are mated with an individual of the same breed. This means, with a little care and planning, the seeds you produce will be true-to-type, keeping their distinct traits generation after generation as long as they do not cross-pollinate with other varieties of the same species. Annual, Biennial, Perennial Not all plants flower, set seed, and die in a single growing season. Those that do, like lettuce, tomatoes, and peppers, are called annuals. Biennials, such as carrots and onions, don’t flower until their second growing season, after they have gone through a cold period. Some long lived plants, like apple trees and asparagus, are perennial, surviving and flowering for many years. Learn About Species A species is a group of individuals that are able to reproduce together. In the garden, most crops are different species from one another, but not always. There are several species of squash and two distinct species of kale - meaning some varieties of these crops are not able to cross pollinate with each other. On the other hand, Cucumis melo, commonly categorized as a melon, also contains some varieties that are sold as cucumbers like ‘Armenian’ because fruits of the variety are unsweet and sometimes pickled. 2. Plan for seed saving Start With Easy Crops Some crops like peas, beans, lettuce, and tomatoes are great for beginning seed savers. These annual, self pollinating crops require little to no isolation, and only a few plants are needed to reliably produce seeds. Grow Enough Plants Some crops have a hard time producing seeds when too few plants are around. Others can reproduce with just a single plant. If the population size of a seed crop is too small, some genetic diversity may be lost and over many generations; in time this can result in a noticeable decrease in plant stature, overall vigor, germination, and yield. Put A Little Space Between Varieties In order to produce seeds that are true-to-type, a little garden intervention is needed to prevent unwanted cross pollination between different varieties of the same species. For some crops like lettuce and peas, all that is needed is a little extra space between varieties. For others, more advanced methods can be used, including larger isolation distances, pollination barriers, or hand pollination. 3. Collect Your Bounty Know When Your Seeds Are Mature For crops that produce wet fruits, the seeds are not always mature when the fruits are ready to eat. Eggplant, cucumber, and summer squash fruit are eaten when the fruits are immature and still edible, but before the seeds are actually mature. This means that seed savers need to leave a few fruits to fully mature in the garden when they want to save seeds. Dry fruited crops, like grains, lettuce, and beans, can be removed from the plant once seeds are dry and hard. Know How To Harvest Seeds Garden crops can be classified as either dry fruited or wet fruited. Collecting seeds from dry fruited crops, can be as simple as going out to the garden, handpicking a few mature seedpods, and bringing them into the house for further drying and cleaning. Fruits from wet fruited crops must be picked when their seeds are mature. The harvested fruits are either crushed or cut open, and the roasted seeds are extracted from the flesh and pulp before the seeds are dried. Store Seeds Raw seeds are happiest when they are stored in a cool, dark, and dry place. A dark closet in a cooler part of the house or a dry, cool basement are both good spaces to store seeds for a year or two. Once properly dried, seeds can also be sealed in airtight containers and stored in the refrigerator or freezer for several years. The seeds of some crops are naturally longer lived. Tomato seeds and beans can be left for many years in adequate storage conditions, while onion and carrot seeds are notoriously short lived. Don’t forget to label your seeds with the crop type, variety name, and any useful notes about your seed source, when you harvested the seeds, and how many plants you harvested from. Snack foods Snack foods are a very broad category with a wide range of processing steps. In general, snack foods have a more robust flavor profile and require a standard or reduced-flavor sage or rosemary antioxidant. If possible, the antioxidant should be added to the dough of the snack food. This could be predispersed in a water or oil phase or added directly to the blender. If adding without predispersion, an antioxidant should be chosen with a less concentrated form of antioxidant and used at a higher dosage rate (i.e., 0.2%). This will allow for even distribution throughout the dough and avoid “hot spots” that could occur when using a more concentrated product. If the snack food does not have a mixing step (i.e., potato chips), the antioxidant could be added to the frying oil or after preparation as a spray-on step. For snack foods, the easiest way to measure oxidation is use of GC to measure hexanal or another marker compound. Is peanut butter good for you? Peanut butter is a firm favorite among adults and children alike. Although tasty, many people wonder about the health benefits of peanut butter. Peanuts and peanut butter contain nutrients that may boost a person’s heart health and improve blood sugar levels. Depending on how people use peanut butter in their diet, it can help them lose weight, or put on pounds during weight training or bodybuilding. However, peanut butter is high in calories and fat, so people should enjoy it in moderation. In this article, we look at the benefits of eating peanut butter and explain the risks associated with consuming it. Peanut butter provides a good amount of protein, along with essential vitamins and minerals, such as magnesium, potassium, and zinc. Most notably, each 2-tablespoon (tbsp)Trusted Source serving of smooth peanut butter provides the following nutrients, minerals, and vitamins: Protein. Peanut butter contains 7.02 grams (g) of protein per 2-tbsp serving. This counts toward the recommended dietary allowances (RDA)Trusted Source for women of 46 g and 56 g for men, which varies by age and activity level. Magnesium. With 57 milligrams (mg) of magnesium, each serving helps towards the RDATrusted Source of 400–420 mg in men and 310–320 in women. Magnesium is essential for health, playing a role in over 300 chemical processes in the body. Phosphorous. Each serving contains 107 mg of phosphorus, which is about 15.3 percent of the RDA of 700 mg for adults. Phosphorus helps the body to build healthy cells and bones and helps cells to produce energy. Zinc. A serving of peanut butter provides 0.85 mg of zinc. This is 7.7 percent of the recommendedTrusted Source daily intake of 11 mg for men, and 10.6 percent of the RDA of 8 mg for women. Zinc is necessary for immunity, protein synthesis, and DNA formation. Niacin. Peanut butter contains 4.21 mg of niacin per serving, which makes a useful contribution towards a person’s recommended intake of 14 to 16 mg. Niacin benefits digestion and nerve function and helps produce energy. Vitamin B-6. With 0.17 g of vitamin B-6 per serving, peanut butter provides almost 14 percent of an adult’s RDA of 1.3 mgTrusted Source . Vitamin B-6 plays a role in over 100 enzyme reactions in the body and may be necessary for heart and immune system health. However, there are also nutritional disadvantages if a person eats more than the recommended amount of peanut butter. Peanut butter is high in calories, saturated fats, and sodium. Each serving contains 3.05 g of saturated fats, which is 23.5 percent of the American Heart Association’s maximum recommended daily intake of saturated fat for those consuming 2,000 calories a day. People should aim for less than 13 g of saturated fat per day. It also contains 152 mg of sodium, which is 10.1 percent of an adult’s ideal daily upper intake of sodium of 1,500 mg.
Publish Date: 29-08-21