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  Things to Consider When Buying a Fan
發佈: hio26io - , 05:31 AM - 版塊: 非楓之谷程式討論 - 無回覆

Fans are a great, cost effective way to mitigate the more intense heat of the summer without having your AC running almost continually. Whether it’s at home, the office, or the outdoor workspace, selecting the right Personal Fan is key to staying cool and achieving energy savings.
While it seems straightforward enough, some overlap exists that may make it confusing when deciding between a standard household fan or a stronger commercial fan. Then there are various types in each category that could require additional consideration. This article will outline some basic guidelines for choosing the right fan for your space.
 
Portable Space Electric Heaters are typically used when the main heating system is inadequate or when central heating is too costly to install or operate. In some cases, small space heaters can be less expensive to use if you only want to heat one room or supplement inadequate heating in one room. They can also boost the temperature of rooms used by individuals who are sensitive to cold, especially elderly persons, without overheating your entire home.
Space Convention Heater capacities generally range between 10,000 Btu and 40,000 Btu per hour and commonly run on electricity, propane, natural gas, and kerosene (see wood and pellet heating for information on wood and pellet stoves).
Although most space heaters work by convection (the circulation of air in a room), some rely on radiant heating. Radiant heaters emit infrared radiation that directly heats objects and people within their line of sight, and are a more efficient choice when you will be in a room for only a few hours and can stay within the line of sight of the heater. Oil Filled Heaters can also be more efficient when you will be using a room for a short period because they save energy by directly heating the occupant of the room and the occupant's immediate surroundings rather than the whole room.
Safety is a top consideration when using space heaters. The U.S. Consumer Product Safety Commission estimates that more than 25,000 residential fires every year are associated with the use of space heaters, resulting in more than 300 deaths. In addition, an estimated 6,000 people receive hospital emergency room care for burn injuries associated with contacting the hot surfaces of room heaters, mostly in non-fire situations.
When buying and installing a small space heater, follow these guidelines:

  • Only purchase newer model heaters that have all of the current safety features. Make sure the heater carries the Underwriter's Laboratory (UL) label.
  • Choose a thermostatically controlled heater, because they avoid the energy waste of overheating a room.
  • Select an Electric Stove of the proper size for the room you wish to heat. Do not purchase oversized heaters. Most heaters come with a general sizing table.
  • Locate the heater on a level surface away from foot traffic. Be especially careful to keep children and pets away from the heater.
 
Humidifier & Aroma Diffusers are often confused, as the products can look similar on the outside or have similar functions. But there are several important differences between these technologies. If you need more moisture in the air in your home, then you need an Ultrasonic Humidifier. If you only want to add fragrance to the air, and not moisture, then a diffuser is the proper product. Diffusers simply do not hold enough water to impact the humidity level of a room.
Having the right humidity level in your home can help you breathe easier, temporarily relieving coughs and congestion. Moisture in the air can also help temporarily relieve dry skin, dry eyes and chapped lips. Proper humidity has important benefits for your whole house as well, including helping to prevent gaps in hardwood floors, cracks in wooden furniture and static electricity that can harm electronics.
 
Air Purifiers sanitize the air, getting rid of pollutants, allergens, and toxins; they're different from air filters, which only remove them from circulation. But how do air purifiers actually work?
Air purifiers have a relatively simple set-up: a fan that sucks in air, and one or more filters. These filters — usually paper, fibers such as fiberglass, or a mesh — capture and neutralize pollutants and particles as air passes over them before the clean air is recirculated into the living space.
They are effective at filtering out most polluting particles, although some are likely to still remain on soft and hard surfaces like furniture or walls. The particular airborne particles that get pulled out of the air depend on the type of air purifier and filter used.
 
Many people are familiar with the daily routine of washing, drying, and styling their hair. Although hair will eventually dry on its own if given enough time, most people reach for a Hair Dryer to speed up the process. While science may have disproven the link between wet heads and catching colds, it's still no fun to sit around with a head full of wet hair, especially in the winter. Hairdryers, also known as blow dryers, were first sold in the 1920s. At first they were pretty dangerous to use -- hundreds of people were electrocuted when they dropped their hair dryer into water-filled sinks and bathtubs.


  Novomichurinsk Ryazanskaya oblast 62
發佈: ForexKnob - , 03:50 AM - 版塊: 圖片影片區 - 無回覆

Nizhnekamsk Respublika Tatarstan 16 Owen Johnston 1987 hartegif Andrew Jennings 1988 steelnsk Christopher Francis 1984 bettru Oscar Cox 1984 mfsc Liam Vargas 1986 sotsprof01 Matthew Hawkins 1981 tpexpert Christopher Burke 1987 tools-info Aidan Harris 1980 repairmanual Owen Ward 1984 supervigilanciaprivada Sam Mckinney 1986 xn----7sbaffod6btnbd7b Luca Bell 1986 itgforum Charlie Pratt 1987 kraftzone Adam Chambers 1986 ips-irk Harry Hughes 1983 xn-----7kcaojafiiehq7albibt1a4be Aidan Wong 1987 malkb Finlay Green 1985 kovkagrodno Louis Clarke 1980 mnogozip


  Flexible Metal Hoses: An essential guide
發佈: ffriw2483a - , 02:55 AM - 版塊: 玩家討論 - 無回覆

metal flexible hose is a type of piping used to connect two distant points to transport or transfer fluid. In Oil & Gas applications hoses are used when there is a considerable relative movements. A variety of fluids and fluidized solids can easily be transferred through flexible hoses to other locations. These are most commonly known as hosepipe. Along with loading and unloading services in processing plants, these are widely used by homeowners as garden hose. Normal Flexible hoses are made of non-metals like soft plastic material or synthetic rubber. However, flexible hoses of chemical industries that are designed to absorb pipe movements are made of metallic materials.
 
Flexible hoses are moade by extrusion or vulcanization process. To add strength to the non-metallic flexible hoses, they are reinforced using a crisscrossed grid of fibers combined together through braiding, spiraling, or knitting. These reinforced hoses can be long enough. Basically, flexible hoses have four parts; inner tube, reinforcement, End fittings and protective outer cover.
 
A corrugated hose is constructed with a bellow of very long length. Fundamentally, the behavior of a corrugated flexible hose is the same as the bellow expansion joint. The flexible hose has to resist the hoop pressure stress, but cannot sustain the longitudinal pressure stress. Also, it has a tendency to squirm under internal pressure. To resist the longitudinal pressure stress and prevent squirm, corrugated hoses are often constructed with braids wrapping around the outside surface as shown in Fig. 4. The braided cover also protects the corrugation from scratch and wear. The braided hose, similar to a tied expansion joint, cannot accommodate any axial movement. On the other hand, the un-braided hose can sustain very small internal pressure.
 
Due to the lack of a limiting mechanism, a corrugated tube connector metal flexible hose is prone to abuse. It should not be bent beyond its acceptable range. For braided hoses, the situation is even more critical.
 
As the corrugations are not visible from the outside, a braided hose does not show immediately when damaged. Therefore, for manual handling in such situations as loading/unloading and switching operations corrugated hose is not suitable. The corrugated flexible hose has a continuous metal wall thus making it pressure-tight. It is suitable for handling any type of gas and liquid as long as it is compatible with the hose material.
 
An interlocked hose is constructed with links that are kept tight with packing material. There are clearances provided between the links that afford the capability of accommodating some axial movement. As the hose is being bent, the clearances gradually close. The hose becomes stiff and cannot bend any further at a certain point when the clearances are completely closed, . This sudden stiffening effect serves as a warning to the handler, preventing the interlocked hose from being over bent. This automatic warning feature makes the interlocked hose especially suitable for manual handling.
 
The packing mechanism at the interlocked links does not offer a perfect seal. Therefore, the interlocked hose is satisfactory for carrying low-pressure air, steam, and water, but is generally not suitable for conveying gases and “searching” liquids such as kerosene and alcohol. The outside of the interlocked hose is relatively smooth, making it easy to handle without any covering.
 
The inner cone with outer thread connector metal flexible hose assembly is normally not analysed. In most of the situations, the end displacements from piping or equipment connections are calculated from stress analysis software and those values are transferred to the vendor for their consideration. Accordingly, the hose length and installation space are determined.
 
Pipe Supporting for optimum flexible hose working
A piping system which utilizes fexible metal hose to absorb pipe movement must be properly anchored and guided to assure correct functioning and maximum service life of the metal hose assembly. The following basic principles should be observed:
 
The direction of pipe motion must be perpendicular to the centerline (axis) of the hose.
To prevent torsional stress, the pipe shall be anchored at each change of direction where a flexible metal hose is employed. Typical examples of correct and incorrect guiding are shown below in Fig. 5.
 
Flexible Hoses are used to accommodate piping and equipment displacements. Hoses being extremely flexible, installations is very easy. However, a few general precautions should be exercised during installation to avoid hose failures.
 
While installing flange connector metal flexible hose, the allowable minimum bend radius is the most fundamental limitation. For interlocked hoses, the limiting radius depends largely on the clearances between links. It has less to do with the stress and fatigue, so it generally has only one limiting radius for all applications. For corrugated hoses, on the other hand, the limiting radius depends on the stress at the corrugations. For pressure hoses with braided reinforcement, the corrugation stress comes mainly from the bending of the hose. Therefore, the corrugation stresses can be controlled by setting a limitation on the bending. In other words, the installation is acceptable if the hose is not bent beyond the limiting radius. Similar to the situation discussed in the bellow expansion joint, the mode of failure of the hose corrugation is due to fatigue. Therefore, the bend radius limitation depends also on the number of operating cycles expected. Most manufacturers provide two limiting radii, one for static application involving a one-time fit-up installation, and the other for operational movement involving many cycles of intermittent flexing. The whole design and installation process actually ensure that this minimum radius is maintained during the initial layout and throughout the operation.
The article describes various types and sources of flexible metal hoses (FMH) vibration. Depending on the direction of vibration displacements, basic variations of sleeves vibration are identified: transversal, longitudinal and torsional. The distinguished forces, that excite vibration in FMH, acting on it, are divided into static and dynamic loads. The most common type of vibration - transverse vibration of flexible sleeves is considered in more details. Also, the ripples - one of the main causes of transverse vibration, which significantly degrade hydraulic performances of pipeline communications, are investigated. The paper presents the analysis of characteristics of the bending and longitudinal stiffness, which implies that the stiffness increases with increasing internal pressure, the diameter of the sleeve and the number of braids. To determine frequency characteristics of FMHs, the bar, with reduced parameters of elasticity and mass, has been chosen as FMH mathematical model. The research results of an influence of various factors on the metal sleeves eigenfrequencies have been studied.
The first step in alloy selection is to determine the source of any potential corrosion. While corrosive attack may be initiated by the media running through the metal hose, it is also possible that corrosion can initiate from external sources.
 
External corrosion
 
If a hose assembly is used in a potentially corrosive environment, then it should be made using an alloy that is resistant to the corrosive agent unless it can somehow be shielded from exposure to that corrosive. This can be tricky, as many covers do not provide adequate corrosion protection, and may even exacerbate the problem. For example, there have been instances where flexible polyvinyl chloride (PVC) covers have been applied onto stainless steel-corrugated dock hoses as a means to protect them from the salt water environment. Over time, these covers can begin to degrade, releasing chloride-containing compounds that can attack the stainless steel hose. External corrosion can also be caused by media that drips or sprays onto the exterior surfaces of the connector.
 
If the media being transferred through the hose or expansion joint is corrosive, then proper alloy selection is critical. Here, it is important to remember that although the product being conveyed may not be corrosive, it may contain impurities that can cause problems. A good example here would be steam transfer. Boiler water may contain various water treatment chemicals such as anti-scaling or anti-foaming agents, and water-softening chemicals, all of which can be corrosive if allowed to concentrate in the system. Natural gas may also contain sulfur-based impurities that can attack commercial stainless steels. This ‘sour gas’ can lead to critical safety issues if system corrosion results in gas leaks. A detailed analysis of the medium may be required in order to identify any corrosive impurities that may be present.
 
Once potential corrosive agents have been identified, the next step is to determine which alloys will best withstand any corrosive attack. Most alloy producers provide detailed specification sheets for the alloys they offer that give valuable insight as to the suitability of a given alloy when exposed to certain chemicals. However, in corrosive applications, industry resources that show real-life test results might provide more reliable data. Various databases are published by organizations which perform corrosion testing on alloys, analyzing their resistance to different chemicals under various operating conditions.
 
Some of these resources are referenced in industry standards and specifications. When using these databases, not only will you need to know the name of the chemical being transferred, but also the temperature and concentration percentage at which it is being conveyed, as these variables can have a dramatic effect on the corrosion rate. For example, sodium hydroxide is generally non-corrosive at low temperatures and concentrations, but becomes aggressively corrosive to stainless steel as the temperature and/ or concentration increases. This is also true for many water-treatment chemicals. Conversely, some chemicals may exhibit reduced corrosion at high concentrations, so caution is key. There are a few important considerations when consulting these corrosion resistance charts. First, they typically do not include any corrosion resistance data for name-brand chemicals or mixtures of multiple chemicals. If name-brand chemicals are being transferred, the chemical manufacturer should be consulted for corrosion resistance data. Secondly, certain corrosion resistance information may be product specific. In other words, corrosion charts that can be found in the back of catalogs for fittings, valves, pipe, etc. should not be used as a reliable corrosion guide for union connector metal flexible hose.
 
While these charts are fine to use as a guide for the products in the catalog, they can be misleading. Although a chart may give an ‘acceptable’ rate of corrosion for those specified products, that same rate may not be acceptable for a flexible metal hose, which is formed using relatively thin-walled corrugated tubing. Incidentally, be wary of corrosion-resistance information found online and make sure that all data is published by a reliable source. Caveat emptor: Buyer beware, especially when the information is free. It is important to remember that, if a metal hose or expansion joint is attacked by a chemical, it is seldom because the alloy is defective. In most cases where corrosion is present, either the incorrect alloy was selected, or the alloy was exposed to unspecified chemicals to which it was not chemically resistant.
 
“If the media being transferred through the hose or expansion joint is corrosive, then proper alloy selection is critical. Here, it is important to remember that although the product being conveyed may not be corrosive, it may contain impurities that can cause problems”


Wink How To Dry Medicinal Plants For Better Storing At Home
發佈: Nicole - , 02:48 AM - 版塊: 賣東西 - 無回覆

How To Dry Medicinal Plants For Better Storing At Home

Drying is the easiest method of preserving medicinal plants. Simply expose the leaves, flowers or seeds to warm, dry air. Leave the herbs in a well ventilated area until the moisture evaporates. Sun drying is not recommended because the herbs can lose flavor and color.
Or, you can just simply put them in a drying machine.These machine could retain the terpenes, flavor, and THC content during drying proccess.
[圖: L.png]
ECO Farm 6 Tray Medicinal Plants Dryer Machine for Indoor Growing Plants 
[圖: 81ojGsDeWGL._AC_SL1500.jpg]
6 tray: Six trays provide plenty of room to get creative drying anything faster! Also comes with a bonus fruit leather sheet and drip tray.
360º circulation: Simple, precise, digital controls activate 360º airflow circulation for thorough uniform drying without overheating- no rotation required.
Transparent door: Door is clear for easy at a glance monitoring of all sheets.
Fresh & healthy: Now you can make a more flavorful, nutrient dense, preservative/additive free, and much much cheaper alternative to commercial products.
ECO Farm 5 Trays Medicinal Plants Dryer Machine For Household 
[圖: 22_226bf65c-c944-4168-b9b4-b143306cbcf3.jpg]
ECO Farm dryer machine can provide a quicker, more efficient  for drying medicinial plant, give you high-quality drying results every time. And it's designed with small size that very convenient to carry.
Easy to Use: This project aims to make your work easier with easy-to-use operation buttons. Just select dehydration. 35-70℃ different composition and different temperature, eight-level adjustment.
5 trays capacity: It also comes with 5 removable stackable trays. Hollow shelf, food grade material, fine workmanship. 
360-degree: The fan and heating element installed at the bottom can provide a stable air flow to achieve the best drying effect without rotating.
Work Effeciently: It dries plant by removing moisture content, shrinking the plant but still retain 97% of nutrients.
This machine could retain the terpenes, flavor, and THC content during drying proccess.
ECO Farm 5 Layers Stainless Steel Drying Medicinal Plants Machine 
[圖: 71J12how2IL._AC_SL1500.jpg]
MULTIFUNCTION FOOD DEHYDRATOR: Ideal for medicinal plants dryer. Dry plants and preserve a range of foods quickly and easily.
SAFE: The bottom-mounted fan and heating element provide constant air flow for optimum drying. No rotation needed. Adjustable thermostat and high quality recipes ensures medicinal plants are dehydrated at their optimal temperature and crispiness.
EASY USE AND CLEAN: Comes with 5 tray system with dehydrating foods at a fraction of the cost of commercially dried foods with no additives or preservatives. The package weight totally just 4.0 kg.Easy to clean and save.
DESIGN: Cleverly designed to circulate heated air across the ingredients to dry them slowly and naturally, locking in flavour and nutrients and keeping them tasty for longer!
ECO Farm 16 Floors Stainless Steel Dried Medicinal Plants Machine Dehydrating Machine Dried Food Dying Machine
[圖: 1234.jpg]

ECO Farm stainless steel dried medicinal plants machine dehydrating machine dried food dying machine can be applicable in many ingredients, such as medicinal plants, fruit, tea...
We also have other options for 8/ 12/ 20 floors Dryer. If you need it, pls feel free to contact us. 

Looking for more options and tools for your harvest? Welcome to visit our official website. Follow us could get the biggest discount. Now using coupon code: Nicole17 to get 17% off when checkout.
Whatsapp: +86 18756546482
INS:nicole9888888


Wink Top Samsung Quantum Board LED Grow Light With Meanwell Diver
發佈: Nicole - , 02:30 AM - 版塊: 賣東西 - 無回覆

Top Samsung Quantum Board LED Grow Light With Meanwell Diver

The ECO Farm Samsung Quantum Grow Lights also features the internationally acclaimed Meanwell Drivers with Direct dimmer control. This gives you the authority to manage plant growth speed and regulate the plants exposure to light intensity. This is Ideal for giving seedlings, cuttings and clones a gentle start in life, right through to high yielding fruits and flowers. 
ECO Farm Full Spectrum LED Grow Light
Samsung 670W/830W Foldable Grow Light Strip With Osram+MeanWell Driver[圖: ECOFarmFullSpectrumSamsung670W830WFoldab...verade.jpg]
[圖: ECOFarmFullSpectrumSamsung670W830WFoldab...ersdsf.jpg]
PROMOTES PLANT GROWTH - Capable of supporting photosynthesis, the LED grow lights are for places where there is little to no sunlight. Ideal for indoor gardens, hydroponics, and aquatic plants, these grow lights are essential in promoting perfect plant growth and maturity.
OUTPUT & EFFICIENCY - Operating at only around 670/ 830W watts with an output of 2077 µmol s-1, this LED achieves an efficiency of 3.1 µmol s-1 per watt. Maximize your yields & profits with ECO Farm LED Grow Lights. Switch from HPS to ECO Farm grow light and increase your yields & profits 30 - 70+% without adding any additional heat, energy costs or cooling requirements. LEDs can deliver more usable light per watt than traditional grow lighting.
EVEN COVERAGE & PAR DISTRIBUTION - The unique 8-bar configuration gives you the ability to mount this LED in rooms with low ceilings, on vertical growing racks, over grow benches and especially in grow tents. For the ideal uniformity, hang the fixture about 12" inches from the crop. This new multi-bar LED fixture type is quickly becoming the new standard, due to the even light spread over the canopy, while easily dispersing heat from the open style bar fixture.
The Full Spectrum ECO-G Series LED GROW LIGHT is a high-performance top-lighting solution for commercial horticulture cultivation. Designed for growers to push the envelope with high PPFD cultivation practices, and high efficacy up to 3.1 umol/J.

ECO Farm 200W/480W/600W Samsung 301B Quantum Board LED Grow Light
[圖: eco-farm-200w-480w-600w-samsung-301b-chi...-light.jpg]
[圖: SJQ-Quantum_Board3.jpg]
Samsung LM301B high bin LEDs, provide your plants with High PPFD value.
Meanwell driver for best power quality control.
Full spectrum (Samsung 301B white light+660nm), high yield.
No fan& No noise design. Its heat is very low when used. 
No dimming, Knob dimming(0-10V), Knob dimming(0-10V)&RJ14 are optional.
ETL & CETL certificated (ETL number:5013683), We are capable of offering 2 years warranty.
The Samsung LM301B uses Osram / SanAn LED light source that is ideal for indoor or greenhouse plant growth lighting.
Top grade driver- Meanwell driver. 
Lens designed for most lighting be collected and using, with IP65 waterproof.
A powerful grow light suitable for the entire life cycle of plants.
new generation which are connected to a heat sink for effective heat dissipation.
Fast for installation, safe for hanging.

Looking for more options and tools for your harvest? Welcome to visit our official website. Follow us could get the biggest discount. Now using coupon code: Nicole17 to get 17% off when checkout.
Whatsapp: +86 18756546482
INS:nicole9888888


  Amazing Ways to Use A Wooden Serving Tray
發佈: Fdlifw2498 - , 02:04 AM - 版塊: 楓之谷相關技術討論 - 無回覆

Serving trays are handy items to have around the home, and a good-
quality wooden serving tray
ranks above all others. While a serving tray can serve many purposes,
it is one of the most preferred home décor items for your personal as
well as entertaining needs.


    Available in a variety of shapes and sizes, such as decorative
round trays, wooden tray sets are a great investment as they make it
easy to carry things around the home, serve food and drinks and use as
a base for placing your décor items – a flower vase, terracotta
figurines and even your green pots on a side table or a centre table.


    



    WONDERFUL WAYS TO USE A SERVING TRAY AT HOME


    



    No matter what you decide to do with a serving tray, one thing is
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    Think about breakfast in bed, and the first thing that comes to
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    On days when you are entertaining house guests in your garden, you
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    BEST-SELLING DECORATIVE WOODEN TRAYS ONLINE AT ARTYSTA GALLERY


    



    DINING TABLE SERVER


    A decorative wooden tray is an excellent purchase for placing
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    Having evening tea in the living room with family and friends
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    Sometimes all you want to do is enjoy the pleasant weather, sipping
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    Beautiful décor items can brighten up your home, especially when
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    Serving trays are undoubtedly one of the hardest working tableware
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    Whether you love to host tea parties and lunches or stay as a
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    While some serving trays are ideal for sharing a specific portion
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    Types of serving trays to buy


    



    There is a wide variety of serving trays available in the
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    When it is time to pick a serving tray to buy you can be flooded
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    What to consider when buying a serving tray?


    



    It is, of course, important to give consideration to the size and
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    You can take things up a notch and match the colour and style of
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    Websites like Ellementry has a wide selection of
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tray.html]wooden food tray[/url] to choose from in different shapes,
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    A nice well-sized tray can be kept at your beverage bar with drinks
ready to be served. The guests can pick their favourite ones and help
themselves while you get to have some free time to enjoy your own
party. Having the drinks already placed in the tray can allow you to
rotate them once in a while if required and lets you mingle up with the
guests.


    



        Fruit platters


    For your next brunch, arrange freshly cut fruits on a wooden
platter and be the talk of the town for your plating skills. Rather
than placing the fruits in a bowl-like fruit salad, why not create a
fruit platter and bring a little bit of style to your table?


    



        Assortment of cheese


    Cheese – who doesn’t love it, right? If you are not sure about
things that you can serve to your guests in a tray, fret not. A
collection of assorted cheese will never disappoint you. Just pick up
some gouda, mozzarella and other favourites and place them on a wooden
tray. Your guests will adore you!


    



        How about some breakfast in bed?


    Want to make your better half feel special? Planning to start a
special occasion on a romantic note? What can be better than a
scrumptious breakfast in bed? Just toss some eggs, pancakes and a cup
of coffee on a beautiful tray like this shade of
[url=http://www.xuyuancraft.com/tray/wooden-trays/breakfast-food-
wooden-tray.html]breakfast food wooden tray[/url] from Ellementry 
and thank us later! Keep a small bouquet of flowers along and you will
not regret it!


    



        Tea


    There is no better way to use a tray other than serving your
favourite tea. Whether you love a hot creamy masala chai, or you are
more of a green tea person, a tray is essential for that perfect
serving of tea. A big tray like this silver metal tray with handles
from Ellementry can even accommodate some go-to snacks as well.


    



        Coffee


    Like to enjoy a cup of coffee with your partner. Well, you do need
a nice tray to pep up your regular coffee drinking experience. A tray
allows you to carry more than two coffee mugs along with some snacks at
the same time besides adding a little more finesse to your experience.


    



        Snacks


    There is no limit to things that you can serve to your guests in a
tray. Whether you are hosting a bunch of kids for a birthday party or
your boss and his family are coming for drinks. You will, of course,
need a couple of trays and platters to serve snacks or take them from
the kitchen to the dining table.


    



    The final word


    



    Serving trays that are good to look at are no doubt versatile and a
very useful accessory to have in your kitchen. While such trays come
handy to serve food and drinks to your guests, they also make your tea
and coffee drinking experience more delightful. Do not forget to
complement your cups and trays!


    



    Besides using these trays for serving purposes, you can also invest
in some beautiful pieces to add to your home décor. Keep it on your
coffee table with a flower vase or a candle to add style to your living
room décor. You can even place some trays on the dining table to keep
your cutlery sorted or organise your cruet set and other mandates.


    



    What do you think of this article? Is there anything that we
missed? What all things do you serve in a tray? We would love to have
your feedback! Do let us know your views in comments below! Do not
forget to check out our tray collection.


    Been a long while since you have added cool new things to your home
collection? If the answer is yes, then it's time to change that and
get shopping. Change is always good, and quirky new pieces can work
instantly to elevate your experience as well as help you make an
impression on your guests. So let's start with the basics, such as
serving trays. With so many stunning options available - from striking
woodwork to contemporary enamel detailing - you will find amazing ways
to serve food and beverages, and even use these trays as decor pieces.


    



    



    Need proof? Take a look at these eight trendy serving trays from
Amazon that you will love:


    



    1. Printelligent Khirki Wooden Serving Tray In Block Style


    This gorgeous tray from Printelligent is sure to spark up your
dining experience. The tray features a fun contemporary design with
pretty printed blocks. It is made of fibre frame with acrylic inserts.


    



    This wooden tray from Paper Plane is designed to be large enough to
conveniently serve a bunch of things. It can help you carry drinks,
hold your favourite books and magazines or prop it on a shelf as a
decorative piece.


    



    This multi-coloured [url=http://www.xuyuancraft.com/tray/wooden-
trays/wooden-coffee-tray.html]wooden coffee tray[/url] from
ExclusiveLane can be used for serving tea, coffee, breakfast and snacks
for dining table and centre table. If you love colours, this is what
you need to pick.


    



    This stylish and unique wooden tray can easily become a focal point
of the living room. In addition to serving hot beverages and snacks, it
is perfect for all occasions.


    



    Add a dash of warmth to your home with this adorable regal elephant
round tray from Chumbak. Quaint, colourful and handy, it is perfect for
kitty parties to breakfast in bed.


    



    A Nourishing Moment. Handcrafted trays help create meaningful
experiences—like enjoying breakfast outside in the sunshine, gathering
the things you need to care for someone you love, or holding your most
treasured objects. Wood pieces like these need protection from water
damage, so use coasters when carrying drinks—or display the trays on
their own to enjoy their beauty.


    



    If you want to find wooden trays recommendation, then you’ve come
to the right place. Because, in this article, I will show you the 7
best wooden trays recommendation that you need to check. Let’s get
started!


    



    This elegant tray is curve-shaped, 16 x 12 x 2 (in), coated in dark
brown with cutout grip handles. The decorative tray is very aesthetic
for home decor. Why should you buy this tray? Because it is made from a
100% well-managed forest! The wooden tray with handles is an eco-
friendly product to keep things clean and tidy!


    



    This wooden tray is uniquely made with many variations of sizes
that you can choose based on your needs! It is handmade with materials
that contain Baltic Birch Plywood, non-formaldehyde glue, varnished
with non-toxic water-based dyes.


  Grow Lights for Indoor Plants and Indoor Gardening: An Overview
發佈: Fdlifw2498 - , 02:03 AM - 版塊: 楓之谷相關技術討論 - 無回覆

Warm vs cool? "Full-spectrum?" LED, CFL, or HID? Here's what you need to know about mars grow light for starting seeds, gardening inside, or houseplants.


    Indoor growing offers many advantages. The biggest benefits are the most obvious: garden pests can’t get at your plants, and you have total control over the weather.


    



    Yet unless you’re lucky enough to have a solarium or greenhouse attached to your home, providing sufficient light to your plants will likely be an obstacle (shade-tolerant houseplants excepted). South-facing windows may provide enough light for a tray or two of seedlings, but if you want to grow vegetables, or any other sun-loving plants, to maturity, you’re going to need LED grow light bar.


    



    The indoor lighting found in most homes does little to support photosynthesis. Traditional incandescent bulbs do not have the proper spectrum of light, or intensity, to supplant the sun. Household fluorescent bulbs can make effective grow lights, but only if they are placed in within a few inches of the foliage and left on for 16 hours per day – not ideal.


    



    When shopping for indoor led grow lights, you’ll notice they are labeled with numbers like 2700K or 4000K. This refers to their relative warmth or coolness on the color spectrum – the higher the number, the cooler the light. Foliage growth is generally best around 6500K, though many plants need a period of warmer light, around 3000K, in order to produce flowers, and thus fruit.


    



    In other words, if your goal is to simply produce seedlings, leafy green vegetables, or root crops, you only need higher spectrum bulbs. If you want to grow flowers, marijuana, or any fruiting plant (cucumbers, tomatoes, peppers, lemons, etc.), you’ll also require low spectrum bulbs. You can some types of bulbs are available in full-spectrum form, however, simplifying things.


    



    The standard fluorescent bulb, commonly denoted T12, makes a decent grow light for houseplants, starting seeds, supplementing the natural light of a window, and other situations where lighting needs are modest. They are fairly weak in light intensity, however, and must be placed within a few inches of the foliage to have much of an effect.


    



    , which are narrower in diameter than T12s (but still widely available wherever lightbulbs are sold), have a much higher light intensity, making them suitable as a sole light source for sun-loving plants. Compact fluorescent bulbs (CFLs) are an option for small spaces, or if you don’t like the look of long rectangular fluorescent light fixtures – CFLs will screw into an ordinary incandescent light fixture.


    



    Look for specialized full-spectrum fluorescent grow bulbs (like this , or , which fits into a standard socket) to provide the right balance of light for flowering plants.


    



    While they are considerably more expensive than fluorescent bulbs, LEDs use half the electricity and last five times longer, more than paying for themselves in the long run. The average LED bulb from the hardware store is not designed for plant growth, however – you need special , a relatively new technology that is increasingly available from horticultural suppliers.


    



    LED grow bulbs are capable of much greater light intensity than fluorescent bulbs and are available in full-spectrum form. An easy rule of thumb: Fluorescent bulbs are often used when growing just a handful of plants; LEDs are preferable for larger quantities since you can achieve higher light intensity per square foot. Another advantage of LEDs? They produce very little heat compared to other bulbs – an issue that can become problematic when you have a lot of lights in a small space.


    



    HID Grow Lights


    Before the advent of LED grow lights, were the main option for large indoor plantings. They are extremely powerful, but are expensive to purchase, consume electricity inefficiently, require special light fixtures, and give off a lot of heat. All that said, they are very effective and are still widely used. If you want to grow large plants like tomatoes or lemon bushes, HIDs are good bet because the light penetrates farther into the foliage than with other bulbs.


    



    There are two types of HID bulbs. High-pressure sodium (HPS) bulbs are best for flowering (low spectrum), while MH (metal halide) bulbs are required to support vegetative growth (high spectrum); the two types are often used in conjunction. Unfortunately, each type requires its own fixture.


    



    How to Install Weed Grow Lights


    Installation requirements vary drastically depending on the scope of your indoor garden and the type of bulb used. But here are a few basic steps to get you started.


    



    Figure out how many bulbs you need.


    Most edible plants require at least 30 watts per square foot, but fruiting species (like tomatoes) generally won’t produce abundant high-quality crops without 40 to 50 watts per square foot. Wattage is always indicated on the bulb package. Simply multiply the square footage of your growing area by the number of watts you plan to provide (between 30 and 50); then divide by the number of watts supplied by the bulbs you plan to use.


    



    Devise a light rack.


    You’ll need a way to support the bulbs over the plants at the proper height. And unless you’re growing something that will remain at more or less the same height throughout its lifespan, you’ll also need a way to raise the light rack as the plants grow. This is usually accomplished through some sort of pulley system or by hanging the light fixtures with metal chain – that way you can easily adjust the height by changing the link the light fixture is home from. are also available for purchase online.


    



    Add the necessary accoutrements.


    It is generally wise to plug your lights into a timer to ensure they get the proper amount of light, and that they get it at the same time each day. are available for indoor growing, though a standard also works. If your lights bring the temperature above 80 degrees or so in your growing area, install a ventilation system to prevent heat stress. Aficionados make use of reflectors and all sorts of other grow light accessories to achieve optimum results.


    



    How Long Should I Leave Grow Lights On?


    Plants grown indoors require more hours of light than those grown outdoors. 14 to 18 hours of light per day is recommended for most edible species when grown under artificial lighting. Don’t be tempted to leave the lights on 24-7, however – at least six hours of darkness each day is essential to plant health.


    



    As the plants grow, raise the light fixture accordingly to maintain the optimal distance, which varies depending on the type of bulb used and its wattage (the higher the wattage.


    As a self-confessed science geek I am fascinated by technology. Yet in the world of gardening this is often synonymous with the gimmicky (fibreglass meerkat solar light, anyone?) or the hugely complex and costly – think hydroponic growers that require a degree in electrical engineering to install. So it was with trepidation that I started experimenting with vegetable grow light last winter in my tiny flat.


    Nine months down the line I am a total convert, eulogising about them to all my gardening mates. They are something I feel could be a gamechanger to many modern gardeners, if we could only get over our preconceptions. This is why…


    



    Once upon a time grow lamps were massive, ungainly things – fluorescent tubes more than a metre long that required complex and hideous systems of stands, cables and reflectors. They were real power guzzlers, too, so not exactly great for the planet, or your wallet – which would already have taken a pretty eye-watering hit from the price of all the kit. They even kicked out quite a bit of heat, which apart from raising safety issues, could also damage the very plants you were trying to grow.


    



    However, recent breakthroughs in LED technology have created a new generation of effective, cool-running grow lights that cost a fraction of the old-school behemoths both to buy and to run, consuming (according to some manufacturers) 90% less energy. Crucially, they have shrunk down enough to be easily incorporated into average living room decor, some seamlessly integrated into planter-cum-lamp designs.


    



    Others are light and thin enough to be fixed pretty much invisibly into standard flat-pack shelves, turning existing pieces of furniture in my house into instant growing units. These LED lights are becoming increasingly widely available online and even at a certain Scandinavian home store.


    



    But why bother in the first place? Surely part of the pleasure of getting out in the garden is to escape the relentless march of technology into every aspect of our lives. Well, here’s what my little experiment has done for me: I was able to grow houseplants in parts of my dark, urban flat that I never could before. This is a huge bonus to an obsessive plant collector like me, and could make an even more dramatic difference to houseplant lovers in basement or north-facing flats where lack of light is a serious issue.


    



    Also, come spring seed sowing, I started off a good six weeks or so earlier and got zero etiolation on my baby plants. Stronger plants, much earlier, meant I got a bumper harvest of tomatoes and chillies weeks ahead of time. And all of this for the cost of a couple of desk lamps than run on minimal power. Brilliant!


    



    Tens of millions have placed their trust in the Guardian’s high-impact journalism since we started publishing 200 years ago, turning to us in moments of crisis, uncertainty, solidarity and hope. More than 1.5 million readers, from 180 countries, have recently taken the step to support us financially – keeping us open to all, and fiercely independent.


    



    



    With no shareholders or billionaire owner, we can set our own agenda and provide trustworthy journalism that’s free from commercial and political influence, offering a counterweight to the spread of misinformation. When it’s never mattered more, we can investigate and challenge without fear or favour.


    



    



    Unlike many others, Guardian journalism is available for everyone to read, regardless of what they can afford to pay. We do this because we believe in information equality. Greater numbers of people can keep track of global events, understand their impact on people and communities, and become inspired to take meaningful action.


    



    



    We aim to offer readers a comprehensive, international perspective on critical events shaping our world – from the Black Lives Matter movement, to the new American administration, Brexit, and the world's slow emergence from a global pandemic. We are committed to upholding our reputation for urgent, powerful reporting on the climate emergency, and made the decision to reject advertising from fossil fuel companies, divest from the oil and gas industries, and set a course to achieve net zero emissions by 2030.


    



    



    If there were ever a time to join us, it is now. Every contribution, however big or small, powers our journalism and sustains our future. Support the Guardian from as little as $1 – it only takes a minute. If you can, please consider supporting us with a regular amount each month. Thank you.


  Effects of Wearing Compression Stockings
發佈: Fdlifw2498 - , 01:59 AM - 版塊: 楓之谷相關技術討論 - 無回覆

This systematic review investigated the effects of wearing below-knee compression stockings (CS) on exercise performance (or sports activity) and associated physiological and perceived indicators. We searched articles on PubMed using the following terms: “graduated compression stockings”; “compression stockings”; “graduated compression socks”; “compression socks” combined with “performance”, “athletes”, “exercise”, “exercise performance”, “fatigue”, “sports” and “recovery”, resulting in 1067 papers. After checking for inclusion criteria (e.g., original studies, healthy subjects, performance analysis), 21 studies were selected and analyzed. We conclude that wearing CS during exercise improved performance in a small number of studies. However, wearing CS could benefit muscle function indicators and perceived muscle soreness during the recovery period. Future research should investigate the chronic effect of CS on Sports Medicine and athletic performance.


    



    The prevention of deep venous thrombosis is one of the first evidence-based benefits of wearing compression sleeve, demonstrated by a clinical experiment in which CS improved the venous return by increasing femoral vein blood flow velocity in hospitalized patients.1 Over time, the interest from the basic medical area has expanded to other fields like Sports Medicine.2 Nowadays, recreational and professional athletes have used CS as a tool for improving performance or accelerate recovery from training or competitions, and also to reduce lower limb volume,3,4 relieve symptoms of muscle soreness, and fatigue.3–6 Such popularity is probably boosted by the possibility to obtain potential ergogenic benefits with a simple and low-cost aid.


    



    There are different types (e.g., shorts for thighs, full-leg) and application modes (e.g., using only after the exercise) for compression garments. However, using CS (bellow-knee) “only during” the exercise are probably more practical (than during recovery, after-exercise) for a significant number of sports/activities. For example, uniform issues would limit whole-body garments in some sports. Also, athletes living in tropical locations could be unmotivated to wear compression garments after training sessions once those garments usually promote higher skin temperatures.7,8 Additionally, there is limited evidence regarding the effects of wearing CS (only) during exercise/training/competition, which could be relevant for Sports Medicine professionals. Therefore, the purpose of this systematic review was to investigate the effect of wearing below-knee CS during exercise (or sports activity) on performance and associated physiological and perceptual indicators.


    



    A systematic literature search was performed by two independent reviewers in PubMed. The following terms: (i) “graduated soccer cotton basketball compression sock”; (ii) “compression stockings”; (iii) “graduated compression socks”; (iv) “compression socks” were combined with “performance”, “athletes”, “exercise”, “exercise performance”, “fatigue”, “sports” and “recovery” (Figure 1).


    



    The studies included in this review met the following inclusion criteria: 1) original studies; 2) comprised samples of adults (≥ 18 yr); 3) participants were healthy; 4) investigated the effects of wearing foot-to-knee (below knee) CS (during exercise) on exercise performance and physiological and perceptual indicators (e.g., muscle fatigue, muscle recovery, musle soreness); 5) trampoline sublimation weed white sock worn during the exercise/test/match; and 6) study protocol included exercise or effort tests and performance analysis.


    



    The literature search occurred between January 01, 1900, until June 30, 2019. We excluded the following type of articles: conference abstracts, case reports, short communications, systematic reviews, meta-analyses, theses, letters to the editor, and protocol papers. Also, we excluded studies involving unhealthy participants: e.g., patients with morbid conditions such as obesity, chronic venous insufficiency, diabetes, hypertension (but not limited to).


    



    Analysis


    The heterogeneity of the selected studies was considerable: e.g., exercise protocols, fitness level of the participants, variables measured. Thus, we have decided not to evaluate the studies chosen from a statistical point of view. Instead, we performed a qualitative analysis, conducted by two authors focusing on the effects reported by the authors and potential practical implications. All other authors read this qualitative analysis carefully, and edits have been incorporated.


    



    Figure 1 shows the search, selection, and inclusion process. The search displayed a total of 1067 papers, which were reduced to 370 after exclusion of duplicate publications. Then, we discarded 39 articles written in non-English languages.9 From the remaining 331 items, we excluded 261 by examining the title. Finally, from the remaining 70 articles, we selected 21 studies for this review according to our inclusion criteria (Figure 1).


    



    Table 1 presents a summary of the studies examining the effects of wearing below-knee CS during exercise on performance and associated indicators. Running was the most common type of exercise in the selected studies (76%, 16 out of the 21 studies), followed by soccer (two studies; 10%), triathlon, calf-rise exercise and cycle ergometer (one study each one; 5%). All studies were performed using a randomized experimental design, with the majority employing a crossover design strategy (13 studies, 62%) (Table 1).


    



    Only two studies found some beneficial effect of CS on performance, and a third study improved subsequent performance (Table 2). Two studies did not find performance effects of CS for the group mean, but the authors highlighted that CS promoted benefits for some individuals. The main effects of CS are presented with compressions between 20 and 30 mmHg. The range between the anti slip wool compression sock values is 12 to 28 mmHg, while the maximum values range from 15 to 33 mmHg.


    



    This systematic review aimed to investigate the effect of wearing below-knee CS during exercise on performance and associated indicators. The main finding is that wearing this kind of CS during exercise (or physical activity) improved performance in a minor part of the studies selected (i.e., 3 out of 21). However, a reasonable number of studies have shown evidence that wearing CS could benefit muscle function or fatigue indicators (e.g., CMJ, specific physical tests) and perceived muscle soreness just after the exercise protocol and/or hours after the exercise bout (e.g., during 1 h, 24 h recovery).


    



    CS and Performance Improvement


    One of the main reasons for wearing CS during exercise is probably the expectation of performance enhancement due to potential physiological effects.2 This includes better venous return which hasten metabolic removal from the exercising muscles31 and reduce cardiac load,26 improved proprioceptive feedback and better movement accuracy,32 reduced muscle oscillations, lower muscle damage, inflammation, and soreness.6,31 In the current review, only three studies found some CS-induced benefit on performance but did not present adirect mechanistic explanation. For example, astudy concluded that wearing CS (during two soccer matches, 72 hin-between) resulted in higher distances covered in high-intensity activities which are decisive for soccer. Also, CS promoted alower perceived muscle soreness in thesecond match.17 Although the authors did not measure any direct muscle damage marker, they suggested that CS probably protected the eccentric actions common in soccer matches,33 mechanically (i.e., smaller muscle oscillation).6 In this regard, the oscillating forces experienced by the muscle resulted in reduced muscle fatigue. Thus, the CS might offer a mechanical advantage reducing muscle oscillation and countering fatigue in high-intensity activities (e.g., intermittent acceleration, changing directions).34,35


    



    Another study showed CS-induced ergogenic effects on performance. The authors found an improvement in running performance concomitantly with anaerobic and aerobic thresholds when participants wore CS.18 The benefits of CS-ergogenic effects on performance are attributed to enhanced biomechanical support of the muscles, leading to higher efficiency and lower metabolic costs at given workloads,18,36 reduction of muscular microtrauma,6 and enhanced the proprioception.32 During a 5 km running time-trial (Brophy-Williams et al15) the wearing CS did not affect immediate performance. However, CS generated a positive impact on subsequent 5 km running (i.e., less performance decrement from time-trial 1 to time-trial 2). Again, the underlying mechanism of such benefit is unclear but may be related to increased oxygen delivery, lower muscle oscillation, and better running mechanics.15


    



    Despite the current results, the literature does not indicate robust evidence favoring the use of CS during exercise (i.e., only three studies found benefits on performance). Researchers should be careful in drawing conclusions. Considering that each specific study has (or had) a particular experimental design (e.g., exercise protocol, duration, intensity, variables measured, fitness level of the participants), it becomes difficult to generalize the results from the different studies. Thus, it is essential to consider the risk of bias and heterogeneity of the studies. As the same protocol does not conduct different studies, they will vary in the characteristics of the included population, interventions, diagnostic methods to access outcomes, etc. (clinical heterogeneity). Thus, these studies may be biased.37 Additionally, two studies did not find CS-induced effects on group mean performance, but the authors highlighted the individual improvements: 10 of 19 runners ran the 5 km time-trial approximately 10 s faster,25 and 10 of the 14 runners ran the 10 km time-trial10 approximately 20 s faster. Therefore, individual responses should be carefully evaluated in practical settings.


    



    CS, Muscle Function and Perceived Muscle Soreness


    Some studies in the current review have shown that CS can induce lower muscle fatigue after an exercise protocol with the same workload than a control condition.11,14,20,21 The lower after-exercise fatigue may suggest a preserved muscle function. Overall, such studies show the maintenance (based on baseline values) of muscle function by a smaller decrement of performance (or none) in specific muscular tests performed after the exercise protocol (e.g., running time-trial, soccer match). On the same reasoning, the lower perceived muscle soreness found in the current review is also a potential beneficial outcome from CS. The smaller muscle soreness may be particularly relevant for more prolonged periods with multiples exhausting physical activities performed with a short recovery period in-between.17


    



    In one of the studies, competitive runners (VO2max ~69 mL.kg.min) completed four 10 km time-trial wearing control CS (0 mm Hg) and CS with different pressures in a randomized, counterbalanced order.11 The runners performed CMJ tests before and after running as a muscle function indicator. The results showed that CMJ height decreased after control running. However, CMJ performance was improved after running wearing CS (low and medium pressure), suggesting a better maintainance of muscle function. The authors speculated that improvements in proprioception to jump and reduced muscle oscillations due to CS probably collaborated with lower muscle fatigue.11


    



    In other included study, highly trained runners participated in 3 simulated trail races (15.6 km, including uphill and downhill) in a randomized crossover trial.14 Authors measured indicators of muscle function (and also muscle perceived soreness) at baseline, 1, 24, and 48 h after-run. Muscle function decreased after the race, suggesting the appearance of fatigue, which was partially counteracted by CS. More specifically, a beneficial effect from wearing CS was found for isometric peak torque at 1 h and 24 h post-run and for CMJ throughout the 48 h recovery period. Perceived muscle soreness was also lower when runners wore CS during trail running compared with the control condition (1 h and 24 h post-run). Specific muscle contractions during trail running (e.g., eccentric on the downhill portion) might result in more extensive muscle oscillation and soreness. Thus, CS probably reduced the perceived muscle soreness due to the higher preservation of muscle function.14


    



    Miyamoto et al20 showed that CS promoted a smaller extent of reduction (- 6.4 ± 8.5% for CS vs. ?16.5 ± 9.0% for control) of the evoked triplet torque, after a fatiguing protocol (15 sets X 10 repetitions) of calf-raise exercise. The authors suggested that mitigation of muscle fatigue observed in their study could be related to increased venous flow velocity and prevention of the lowering of the intramuscular pH.20


    



    Positive CS-induced benefits on muscle fatigue was also described after a soccer match. Female players of both teams (50% each team, randomly wore CS or control socks) performed tests (agility T, standing heel-rise, and YoYo Intermittent Endurance II) 48 h before (baseline) and immediately after the game. CS resulted in less match-induced fatigue for agility T-test performance (maintenance for CS and decrement in control players) and heel-rise test (both groups had a decrement on the number of repetitions, but higher in control).21


    



    In the current review, some researchers found a beneficial CS-effect on the perceived muscle soreness in lower extremities after the following exercises: high-intensity continuous 10 km road-running,10 15.6 km trail in mountainous terrain,14 in the second match of soccer (72 h between the first game),17 and 24 h post 5 km time-trial.25 Overall, those studies suggested a lower perception of muscle soreness due to less extensive muscle damage (lower muscle oscillation), and better proprioception. However, we cannot rule out a potential placebo effect, once it is hard to control such bias due to the nature of compressive CS versus control socks.


    



    CS, Other Potential Benefits, and Final Considerations


    Besides performance, muscle soreness, and muscle function indicators, 15 out of the 21 studies selected in this review presented other variables influenced by CS: lower blood lactate levels,13,22,23 and fibrinolytic activity,29 higher oxygen saturation,19 after the exercise protocol (recovery). Also, lower cardiac stress during exercise has been found.26


    



    Mitigation of exercise-induced muscle damage is a possible effect according to authors that found benefit from wearing CS in this review. However, none of them measured blood markers of muscle damage (e.g., creatine kinase - CK, lactate dehydrogenase - LDH). Curiously, only three studies measured such markers after-exercise: a marathon race,12 a 15.6 km trail-running,14 and half-ironman triathlon competition,16 and found no effect from CS. The lack of measurements of muscle damage markers on several studies herein included may be due to the experimental design and the fact of “only” wearing the CS during the exercise (i.e., more focus on performance than recovery). Longer time-points of measurement after the activity (e.g., time-course of CK for at least 24 h after-exercise) could be necessary to detect a significant change in CK,38 for example.


    



    Finally, we highlight that in a real-world scenario, athletes probably will not use a promising ergogenic aid to improve performance (e.g., CS) only once, as the majority of studies included here. Athletes would perhaps try it in a couple of training session and one competition before to make a final decision. Also, in practical terms, athletes usually may combine different strategies to improve performance and later recovery, such as ischemic preconditioning,39,40 myofascial release, and cold water immersion.41 Currently, the effects of such strategies (isolated or combined) with CS are unknown. Therefore, the interpretation of our findings should have in mind “to see also the forest, not just the leaf”.


  A NONELASTIC RUBBER STRIP DRAIN
發佈: Fdlifw2498 - , 01:58 AM - 版塊: 楓之谷相關技術討論 - 無回覆

The use of doubled strips of rubber dam material for drains has become general in this clinic, especially for wounds that do not require irrigation. These have been found superior to tubing and the ordinary type of cigaret wicks because they are nonirritating to the wound and the capacity of the drain is increased as a result of the capillarity derived from the two opposed surfaces of the rubber dam material. On removal, these drains leave very little deformity in the tissue and they do not tend to plug the wound, as do wick or tube drains frequently.


    



    This type of material has the fault of stretching considerably and of sometimes breaking, a portion being left within the wound. To obviate this we have strengthened strips of rubber dam material by running a seam down the center with a sewing machine. This makes the rubber nonelastic and adds sufficiently to its tensile


    



    The proper assembly of underground precast concrete structures is often critical in the construction of underground structures. In particular, interfacial waterproofing between precast concrete segments is a key factor influencing use, safety, and life span. Current practice is to incorporate waterproofing rubber strips in the design. During the installation process, compressive stress is applied to the strip by post-tensioning to achieve performance. For this paper, lateral constraint compression tests were carried out on composite rubber seal strips that utilize putty. Special waterproofing and sealing test devices were designed to investigate corresponding relationships between water pressure and compressive stress (or strain). A relationship between water resistance pressure and compression stress and strain of the putty-based composite rubber strip was proposed based on the series tests and the control target of the minimum compression strain of the putty composite rubber strip was then suggested. Finally, full-scale waterproofing tests on tunnel joints were conducted. The experimental results provide a scientific reference for the engineering application and design of composite sealing rubber strips putty for underground post-tensioned precast concrete structures.


    



    Waterproofing is typically a key design goal for underground precast concrete structures (Ossai 2017). For modern tunnel structures, segments often require casting of high performance concrete with very low permeability (DAUB 2013). Therefore, the primary possible leakage point considered is the segmental joint (Yurkevich 1995; Lee and Ge 2001; Henn 2010; Wang et al. 2011; Wu et al. 2014; Fang et al. 2015; Soltani et al. 2018). For tunnel lining, one of the most significant factors impacting the overall behavior and structure response was the existence of the segmental joints for precast concrete units (Wood 1975; Koyama 2003). Due to the underground environment, repair after the leakage in the structure is very difficult. In general, design service life for underground structures ranges from 75 to 100 years. Structures within urban underground tunnel networks tend to deform due to the long-term dynamic load and impacts associated with surrounding buildings. Under working conditions, the largest deformation was frequently observed and entered into failure state at the joint (B?er et al. 2014; Huang et al. 2015; Hong et al. 2016). Therefore, waterproofing materials need to accommodate structural deformation.


    



    In present concrete construction, elastic rubber strips in sealing and waterproofing joints of assembling segments have been commonly used. For underground concrete structures, standard design for sealing joints uses Ethylene-Propylene-Diene Monomer (EPDM) polymer rubber strips arranged circumferentially on the end faces of the segment (Ding et al. 2017). Putty-based composite rubber strips have great viscosity and elasticity, which can compensate to a certain degree for the adverse effect of the interface defects at joints. To evaluate the waterproofing ability at joints, special attention is directed to the sealant behavior of the EPDM sealing strips. A time-dependent constitutive model is proposed to assess the long-term waterproof ability of EPDM rubber used in segmental joints (Shi et al. 2015). At present, there are few requirements for rubber strips in the design specifications, and there is limited understanding of the relationship between applied forces and waterproofing performance. In addition, precast concrete structures incorporate a groove at the joint interface for the rubber strip positioning (Hu et al. 2009). The type of groove at the joint interface can limit extruded profile epdm rubber seal strip lateral deformation, which can increase pressure on the strip and improve waterproofing ability. The various types of grooves offer different degrees of constraint. Therefore, mechanical properties of rubber strips along with groove design at precast concrete structure joints are key elements in waterproof design. The joint open width is also regarded as a key performance indicator, since it is the weakest part of the shield segmental lining (Liao et al. 2008; Zhang et al. 2015). As the weakest and vulnerable point in the segmental lining, joints have been investigated in experiments (Ding et al. 2013; Liu et al. 2015; Kiani et al. 2016), numerical analyses (Ding et al. 2004; Teachavorasinskun and Chub-uppakarn 2010) and case studies (Jun 2011; Basnet and Panthi 2018). Testing apparatus was designed to accurately monitor water leakage pressure of segmental joints under various combinations of opening and offsets (Ding et al. 2017). Molins and Arnau (2011) presented an in situ load test and 3D numerical simulation on a full-scale segmental lining for the Barcelona metro line. According to a case study in Shanghai, Huang et al. (2017) perceived that longitudinal joints of the metro tunnel have large open widths and lose waterproofing when disrupted by unexpected surcharges.


    



    In this paper, mechanical tests for compressive stress and strain of putty-based composite rubber strips along with waterproofing performance tests at the interface between putty-based composite rubber strips and concrete are conducted. These tests investigate influence of strip compressive force and the joint stretching value on waterproofing of sealing rubber strips. It attempts to establish a design model and proposed control target for mechanical and waterproofing properties of this new type of rubber strip. Waterproofing test of a full-scale tunnel joint is carried out. The research work of this paper provides a scientific reference for the engineering application and design of composite sealing rubber strips with putty for underground post-tensioned precast concrete structures.


    



    The putty-based composite silicone weather stripping extruded rubber strip was made up of Ethylene-Propylene-Diene Monomer polymer rubber (EPDM foam strip) and the external composite layer (putty paste) of high viscosity reactive polymer cement (butyl rubber). The primary reason for use of the composite was to take advantage of the external putty-based material’s properties of viscosity and superplasticity, which can heal mesoscopic cracks and defects on the surface of concrete structures to improve interface waterproof ability. Cross section dimensions and picture of the rubber strip are shown in Fig. 1.


    



    Figure 2 displays the lateral confinement loading test device, which is composed of two parts: convex shape of the upper part and concave shape of the lower part. The inner and outer diameter of the annular groove was 170 mm and 220 mm, respectively. The upper part has protrusion that squeezes the strip, and the annular groove is set at the lower part of the device with an annular rubber strip installed in it (see Fig. 2c). The length of the EPDM foam rubber in the elastic state has 640 mm, and the compression area is 15,315 mm2. Quasi-stress control was selected for the tests.


    Experimental results of the putty-based composite strip under lateral confinement for compressive stress and displacement are provided in Fig. 7. At the early stage of loading, the compressive stress of the composite strip gradually increased with the displacement. It was observed that the displacement dramatically increased and at the later stage of the loading when the load reached at 112.36 kN primarily maintained at 11 mm. At end of the test, the rubber strip was not crushed and the internal EPDM foam rubber after unloading almost recovered to its original shape. The maximum displacement of the putty-based composite rubber strip under lateral confinement was approximately 11 mm, which was brought on by the squeezing of the inner hole of the composite strip raising the internal pore of the EPDM rubber. The instantaneous elastic recovery during the unloading process was 85% of total deformation. The residual deformation of the composite rubber strip was gradually recovered to its original state with time. Eventually, the rubber strip was not damaged. The deformation recovery of the inner elastic material to its original shape can partly drive unrecoverable external putty material.


    



    In the loading process, the two end faces of the rubber sealing strip weatherstrip for window were partially extruded upon loading, since they were not restrained at the end face (see Fig. 8). When maximum deformation was reached, the upper and lower parts of the concrete were in contact with each other.


    



    There was an inflection point in the curves of the rubber strip in the two different grooves, as presented in Fig. 10. Before the point, the internal pore and middle hole of the sealing strip were not tightly compressed signifying that the compression strain increased gradually with compressive stress. Moreover, the relationship between compressive stress and compression strain for the two different sizes of groove were almost the same before the inflection point. At the inflection point, the central hole of sealing strip and the pore of foam rubber were completely compressed. The whole strip was so dense that the compressive force increased sharply with the compression strain. The compressive stresses of the sealing strip in the two different grooves at the inflection points were almost the same and their corresponding compression strain differed by roughly 20%.


    



    In the early stage of compression, the compression moduli of the Waterproof Rubber Seal Strip Gasket were almost the same under the two groove constraints. In the later stage of loading, the compression stress of 6 mm depth of groove was greater than that of 4 mm depth under the same compression strain, and the compressive strain of the 4 mm depth of groove was greater than that of the 6 mm depth of groove under the same stress. This was mainly attributed to the difference in the constraint degree of the groove to the strip at the later stage of loading. In the final stage, the two compression interfaces of the 6 mm depth specimens were close in contact with each other. The remaining space at the joint was rather small, and there was no compression space. However, there was still a large space between the two interfaces of the 4 mm deep specimens. This was mainly due to the sum of the strip deformation and groove depth limit. The bilinear outsourced line was taken as an approximate stress-deformation relation model as shown in Eq


    



    The tests started with two culverts gradually assembled in place. After initial post-tensioning, dial gauges were installed inside the culverts to measure joint space variations in the process of post-tensioning. Simultaneously, the strains on the post-tensioning steel bars were recorded. The water injection pump and water pressure gauges at the lower part of the water injection hole of the box culvert were installed. After the steel bars were set in the duct, the conductor was run through the perforated sheet. The sheet was tightly attached to the concrete surface and bolts fastened. Table 2 provides experimental results of the post-tensioning process. The upper and lower prestressed steel bars were tensioned at the same time, otherwise the friction resulted in the vertical location due to the friction at the bottom so that the two tendons were employed. Upon completion of a post-tensioning cycle, the gap change and steel strain were measured. The bolts were then fastened. The maximum tension force was 180 kN. During the post-tensioning process, strain of steel bars varied linearly, indicating that the post-tensioned steel bars were in the elastic state with strain close to the theoretical value.


    



    In order to investigate the waterproofing performance of the putty-based composite rubber, mechanical behavior tests using rubber strip and waterproofing performance tests of the interface between the strip and precast concrete were performed.


  Printed Circuit Boards
發佈: Fdlifw2498 - , 01:56 AM - 版塊: 楓之谷相關技術討論 - 無回覆

OrCAD PCB Editor is based on Allegro PCB Editor, so this book will
be useful to new Allegro [url=http://www.ideaspcb.com/printed-circuit-
boards/]printed circuit boards[/url] Editor users as well. Allegro PCB
Editor is a powerful, full-featured design tool. While OrCAD PCB Editor
has inherited many of those features, including a common file format,
it does not possess all of the capabilities available to the Allegro
PCB tiers, such as Allegro High-Speed Option, Analog/RF Option, FPGA
System Planner, Design Planning, and Miniaturization Option.
Consequently most of the basic tools and features are described here,
but only a few of the more-advanced tools are covered, as outlined
later.

PC board traces must be sized appropriately (both in width and
thickness, or copper weight10) to carry the current that you need
without excessive temperature rise. A rule of thumb is that a 10-mil-
wide, 1-ounce PC board trace can carry in excess of 500 mA with a 20 °
C temperature rise above ambient. PC board copper weight vs. trace
thickness is shown in Table 15.5. An estimate of the current-carrying
capability for 20 °C temperature rise of PC board traces is shown in
Figure 15.12. The fusing current (Figure 15.13) for PC board traces is
significantly higher.


    



    OK – So What’s a Printed Circuit Board?


    I’ve just mentioned a printed circuit board, but what exactly is a
printed circuit board? Well, look inside any modern electronics
appliance (television, computer, mobile phone, etc.) or even many
electrical appliances (washing machine, iron, kettle, etc.) and you’ll
see a printed circuit board – often known by the

multilayer PCB
.


    



    A printed circuit board is a thin baseboard (about 1.5 mm) of
insulating material such as resin-bonded paper or fiberglass, with an
even thinner layer of copper (about 0.2 mm) on one or both surfaces.
(If copper is only on one surface it’s then known as single-sided
printed circuit board; if copper is on both surfaces it’s known as
double-sided printed circuit board.) The copper on the surface of a
printed circuit board has been printed as a circuit (yes, OK, that’s
why it’s called printed circuit board – geddit?), so that components
on the printed circuit board can be soldered to the copper, and thus be
connected to other components similarly soldered. Photo 12.1 shows a
fairly modern printed circuit board to show you what they look like.
The printed circuit board shown is quite a complex one, with hundreds
of components – from a computer actually – but the printed circuit
board in a washing machine, say, may only hold a handful of components.
Photo 12.2 shows how the copper on a printed circuit board comprises a
pattern of copper – sometimes called the copper track – rather than a
solid layer. This pattern or track is the key to making connections
between components.


    PCB design begins with an insulating base and adds metal tracks for
electrical interconnect and the placement of suitable electronic
components to define and create an electronic circuit that performs a
required set of functions.


    



    The term printed isn’t exactly an accurate description of how the
copper on the surface of a printed circuit board is formed. In fact,
all printed circuit boards start life with a complete layer of copper
on one or both sides of the insulating board. Then, unwanted copper is
removed from the board, leaving the wanted copper pattern behind.
Typically, this copper removal is usually – though not always – done
by etching the copper away using strong chemicals.


    



    Figure 12.1 shows a cross-section of a simple printed circuit
board. In it you can see the insulating board, the copper track, and
the holes for component leads. Components fit to the printed circuit
quite easily. Their leads are inserted through the board holes, and are
then soldered to the copper track. Figure 12.2 shows how this works. In
terms of the amateur enthusiast in electronics, simple (and relatively
inexpensive) hand-tools are all that are required in this soldering
process – we’ll look at these, and how to use them, later.


    Initially, a design specification (document) is written that
identifies the required functionality of the

thick copper PCB
. From this, the designer creates the circuit
design, which is entered into the PCB design tools.

The design schematic is analyzed through simulation using a suitably
defined test stimulus, and the operation of the design is verified. If
the design does not meet the required specification, then either the
design must be modified, or in extreme cases, the design specification
must be changed.


When the design schematic is complete, the PCB layout is created,
taking into account layout directives (set by the particular design
project) and the manufacturing process design rules.


On successful completion of the layout, it undergoes analysis by (i)
resimulating the schematic design to account for the track parasitic
components (usually the parasitic capacitance is used), and (ii) using
specially designed signal integrity tools to confirm that the circuit
design on the PCB will function correctly. If not, the design layout,
schematic, or specification will require modification.


When all steps to layout have been completed, the design is ready for
submission for manufacture.


1.2 EMC on the Printed Circuit Board
Almost every printed circuit board (PCB) is different and completely
application specific. Even within similar products the PCB can be
different, for example open two PCs from different manufacturers, with
the same processor, clock speed, keyboard interface, etc., the actual
PCB layout will be different. This diversity means that every
high
tg PCB
has a unique level of EMC performance, so what can
possibly be done to ensure that this is within certain limits?


It should not surprise circuit designers that the layout of the PCB can
have a significant effect on the EMC performance of a system, usually
more so than the actual choice of components. Consequently, PCB layout
is one of the most critical areas of consideration for design to meet
EMC regulations.


The fact that there are so many different PCB designs in existence is a
testimony to the low cost of producing a PCB, but relaying a complete
PCB because of poor layout design causes significant increases in costs
not present in the actual material price of the board. Relaying a PCB
will create a delay in time to market, hence lost sales revenue. New
PCB layouts or changes usually entail new solder masks, reprogramming
component placement machines, rewriting the production instructions,
etc., hence cost may not be present in the final product part cost, but
in the development and production overhead.

Although a significant factor in overall EMC performance, the
recommendations for minimising the effect of PCB layout on EMC are
general good PCB design practices. The cost of implementing these
recommendations is solely in the time taken to ensure that these good
design practices are implemented, vigilance and experience are the two
main requirements, not necessarily new design software or extensive
retraining.

Printed circuit boards (PCBs) are by far the most common method of
assembling modern electronic circuits. They comprise a sandwich of one
or more insulating layers and one or more copper layers which contain
the signal traces and the powers and grounds; the design of the layout
of PCBs can be as demanding as the design of the electrical circuit.


Most modern systems consist of multilayer boards of anywhere up to
eight layers (or sometimes even more). Traditionally, components were
mounted on the top layer in holes which extended through all layers.
These are referred to as “through-hole” components. More recently,
with the near universal adoption of surface mount components, you
commonly find components mounted on both the top and the bottom layers.

The design of the PCB can be as important as the circuit design to the
overall performance of the final system. We shall discuss in this
chapter the partitioning of the circuitry, the problem of
interconnecting traces, parasitic components, grounding schemes, and
decoupling. All of these are important in the success of a total
design.

PCB effects that are harmful to precision circuit performance include
leakage resistances, IR voltage drops in trace foils, vias, and ground
planes, the influence of stray capacitance, and dielectric absorption
(DA). In addition, the tendency of PCBs to absorb atmospheric moisture
(hygroscopicity) means that changes in humidity often cause the
contributions of some parasitic effects to vary from day to day.


In general, PCB effects can be divided into two broad categories—those
that most noticeably affect the static or DC operation of the circuit,
and those that most noticeably affect dynamic or AC circuit operation,
especially at high frequencies.

Another very broad area of [url=http://www.ideaspcb.com/printed-
circuit-boards/high-frequency-pcb/]high frequency PCB[/url] design is
the topic of grounding. Grounding is a problem area in itself for all
analog and mixed-signal designs, and it can be said that simply
implementing a PCB-based circuit does not change the fact that proper
techniques are required. Fortunately, certain principles of quality
grounding, namely the use of ground planes, are intrinsic to the PCB
environment. This factor is one of the more significant advantages to
PCB-based analog designs, and appreciable discussion in this section is
focused on this issue.


Some other aspects of grounding that must be managed include the
control of spurious ground and signal return voltages that can degrade
performance. These voltages can be due to external signal coupling,
common currents, or simply excessive IR drops in ground conductors.
Proper conductor routing and sizing, as well as differential signal-
handling and ground isolation techniques enable control of such
parasitic voltages.


One final area of grounding to be discussed is grounding appropriate
for a mixed-signal, analog/digital environment. Indeed, the single
issue of quality grounding can influence the entire layout philosophy
of a high performance mixed-signal PCB design—as it well should.


Function of OrCAD PCB Editor in the printed circuit board design
process

PCB Editor is used to design the PCB by generating a digital
description of the board layers for photoplotters and CNC machines,
which are used to manufacture the boards. Separate layers are used for
routing copper traces on the top, bottom, and all inner layers; drill
hole sizes and locations; soldermasks; silk screens; solder paste; part
placement; and board dimensions. These layers are not all portrayed
identically in PCB Editor. Some of the layers are shown from a positive
perspective, meaning what you see with the software is what is placed
onto the board, while other layers are shown from a negative
perspective, meaning what you see with the software is what is removed
from the board. The layers represented in the positive view are the
board outline, routed copper, silk screens, solder paste, and assembly
information. The layers represented in the negative view are drill
holes and soldermasks. Copper plane layers are handled in a special
way, as described next.


Fig. 1.17 shows routed layers (top and bottom and an inner, for
example) that PCB Editor shows in the positive perspective. The
background is black and the traces and pads on each layer are a
different color to make it easier to keep track of visually. The drill
holes are not shown because, as mentioned already, the drilling process
is a distinct step performed at a specific time during the
manufacturing process.


PCBs usually contain epoxy resin, fiberglass, copper, nickel, iron,
aluminum and a certain amount of precious metals such as gold and
silver; those materials and metals along with electronic parts are
attached to the board by a solder containing lead and tin. The main
material composition of PCBs was determined and is shown in Table 13.1.
From the table, the composition of metals, ceramic and plastics could
reach 40%, 30% and 30%, respectively. Further, the concentrations of
precious metals in waste PCBs are richer than in natural ores, which
makes their recycling important from both economic and environmental
perspectives. Table 13.2 shows the average content and value ratio of
different metals in PCBs. One can see that Au, Cu, Pd and Ag account
for nearly all of the economic material value in waste PCBs. Therefore,
PCB recycling focuses on recovering these metals above all else.


For the technology and engineering of very complex boards, the United
States, the United Kingdom, Germany and France still have a competitive
advantage. There is every reason to believe that the advantage will
soon be lost to Asia. Asia produces three-fourths of the world’s PCBs,
with over 1000 manufacturers in China alone. The PCB industry, like the
larger electronics industry, has always had a global component. Only in
the past four years, however, has the US manufacturing base faced a
serious decline. In 2003, the United States produced 15% of the world’
s PCBs, trailing Japan, the largest producer at 29%, and China, the
second largest at 17%. Taiwan was the fourth largest producer at 13%.
Europe produced only 10%, and South Korea 8%. No American company is
now among the top ten manufacturers of PCBs. China has overtaken Japan
as the leader in PCB production and is forecast to produce $10.6
billion worth of PCBs, accounting for 25% of the world total (LaDou,
2006).