What is the difference between a contactor and a relay?
Electromagnetic relay and contactor could work in the same way. Sometimes they can act as the same device. Sometimes to use contactor in circuits and sometimes to use relays in circuits. How to know the differences? It depends on their specific uses to differentiate.The main function of the relay is to perform signal detection, transmission, transformation, or processing. It is usually used in the control circuit (compared with the "main circuit").The main function of contactor is to connect or disconnect the main circuit. The concept of the main circuit corresponds to the control circuit. The current of general main circuit is larger than that of control circuit. The contactor with large capacity usually has an arc extinguishing cover, because arcing will arise when large current to be cut off. The contact will burn with arc cover to distinguish the arcing.If a main circuit has a smaller working current, relays or such devices can be used in such main circuit to act as contactor. But if a main circuit is of very large current , then it entails the contactor also to be of very large current. That is to say, the current in the control circuit is very large, and it is difficult to use the ordinary relay to make or break the control circuit. At this point, contactor or such devices are to be used as a switch for the control circuit.You can refer to our website www.xinlielectric.com for relay and contactor products information
Are there any disadvantages of colored contact lenses over transparent ones?
Looking at both categories labeled as clear and color makes a big difference already.Clear contact lenses are manufactured in a process where no exposure of ink happens. This means that the material itself is ideally designed for oxygen permeability allowing you eyes to receive the required amount of oxygen to pass through your eyes sustaining the amount of tear liquid.Color contact lenses depending on the print technology applied will vary how breathable and comfortable it will be. Contact lenses in the material of silicone hydrogel are well known to be more comofortable than the others. If you prefer to use colored contacts, it will be practical to use daily disposable than using quarterly or yearly disposable as the more you use these contacts, the more it gets expose to foreign materials which will lead to cross contamination affecting the quality of comfort and convenience.Try checking the website lens.me - Contact Lenses | Solotica | USA | Middle East | Buy Lenses Online the place where I buy my contact lenses as they do provide essential information for all contact lens which I find very important when buying medical stuff like contact lenses.I hope this helps. <3
What is the difference between a Scanning Electron Microscope and a Transmission Electron Microscope?
SEM detects electrons which reflected from the surface of the sample. TEM detects electrons which went through the sample. (That should help if you have trouble with concepts of "scanning" and "transmission".) Thus SEM shows the surface of the sample, and TEM can show its inside (sometimes down to seeing individual atoms, if the TEM is very good and the sample very thin). I made this figure for my co-students who had the same question.Source of microscopic images: Microscopic Imaging of Rosette Nanotubes
How do you differentiate between glass and glass fiber?
MaterialCarbon fiber is made with small strands of carbon atoms that are combined into strands woven together to form an incredibly durable and lightweight material. Fiberglass is made of small glass fibers that are connected together to form a material. The glass is made of silicon and not carbon.UsesBoth carbon fiber and fiberglass are used to make bodies and hulls of ships because of their strength and light weight, but they are also suited for other uses. Carbon fiber, which is 10 times stronger than steel, is used to make golf club shafts. Fiberglass is used for insulation in homes and businesses.HealthCarbon fibers have no real heath issues because it is manufactured as a solid piece of material, unlike fiberglass which is made of tiny glass particles. Fiberglass that is not sealed with an epoxy can irritate your skin and cause a rash if you touch it. The small glass particles actually cut the skin. Fiberglass is especially dangerous if it is inhaled because it can cut the lining of the lungs.EpoxyCarbon fibers are strands of carbon atoms woven together to create a single mass, while fiberglass requires an epoxy or covering to maintain its strength and durability. Without the hard outer covering, fiberglass would easily come apart. Carbon fiber doesn't need a covering or an epoxy.Visit: http://www.eas-fiberglass.net/
What Is The Difference Between Ektachrome and Kodachrome?
Kodak's Kodachrome is a legendary type of slide( aka Positive or reversal)* film. Released in 1935,this epic film was, in fact, the first commercially successful color film in existence. Despite how great the film is(It has a completely unique, natural look and is one of the best photographic films for archiving), it was discontinued late last year. The antiquated process for developing this film, K-14, is considerably more costly and it is very complex compared to modern films that instead require E-6 processing (About 6 steps versus 17). People wanting to shoot Kodakchrome film need to do so before December of this year. The last k14 lab will cease processing at that point. This is the world's most famous image, caputed on Kodachrome: ( http://upload.wikimedia.org/wikipedia/en... ) And another example: (http://www.burnmagazine.org/wp-content/u... ) You can no doubt see why it's was- and still is- so popular. --------------------------- Kodak's Ektachrome slide film came into existence about a decade after Kodachrome. It's process and emulsions have continued on up to present day and show no signs of going away. There are different Ektachrome films around with different characteristics and all are very modern. For example: Ektachrome E100VS is very saturated ( http://www.flickr.com/photos/doistrakh/3... ) while E100G is more neutral, with natural skin tones ( http://www.flickr.com/photos/zgodzinski/2435267960/ ) They require E-6(or equivalent) processing. Not many 1-hr labs still have e-6 processing but it's definitely still around. In short: -Kodakchrome is an older, discontinued, and arguably 'obsolete' type of film with exceptional properties. -Ektachrome is a more convenient family of films for the modern world. They can be used just the same, though, will give different results as far as image properties are concerned. ------------------ *Slides: http://en.wikipedia.org/wiki/Transparency_(photography)
If all the cells in our body have the same DNA, then why aren't they all the same kind of cell? How can there be different cell types, shapes, and functions?
Because each has a different subset of the whole genome turned on. Some functions are common to all cells - they will have active genes for say tubulin and spectrin, as all will have a cytoskeleton of some ilk for example - so all cells will have those genes 'turned on', though the levels of activity will differ depending on cell type. Other genes are specific to a given cell type - you only get haemoglobin in red blood cells.There is are further layer of controls over how much of a given gene product is made, all cells have tubulin, but some types will have more than others, and these regulators themselves are under genetic control.And the action of all these gene products together detrmine the form and function of the cell. And cells do chnage their gene expression over time as they are newly formed, mature and die. The way skin cells work, dividing in deeper layers and accumulating keratin as they are pushed towards the outside of the organism and eventually becoming dead slabs of keratin and flaking off is one example.An explanation with a video -What Is Cell Differentiation? - Process, Importance & Examples - Video & Lesson Transcript | Study.com These might help, but Wiki articles can be a bit impenetrable at times -Regulation of gene expression Cellular differentiation Trying to work out these processes is a major field of research as getting a fully differentiated cell back down a few steps or even all the way being a stem cell would be a very handy thing to do.http://www.wellcome.ac.uk/About-...
Why is the colour of kerosene blue?
In 1950s Australia kerosene was colourless. There were fairly frequent fatalities from people, usually children, drinking it from bottles by mistake for lemonade, water and other colourless drinks.Since bottled drinks were brown, red, green, yellow etc. blue was chosen so it least resembled bottled drinks. Later, a specially shaped bottle was introduced. Kerosene drinking fatalities are now almost unheard of.In other countries kerosene may be coloured differently because of different tax regimes and subsidies. There are no subsidies for kerosene in Australia, you pay full price including taxes.In Australia, “kerosene” is not used as a name for various forms of Diesel or jet fuels. These are chemically different from standard kerosene. The name “kerosene” is restricted to lighting kerosene formulated for use in lamps, lanterns, old refrigerators and some small pressure stoves.