Wednesday, January 29, 2020

The resistance of the wire Essay Example for Free

The resistance of the wire Essay The atoms take up more space so there is more chance of the electrons being caught by them; more energy is going to be lost as heat. As temperature increases so does resistance. If we increase the cross section there will be a bigger area, so more free electrons available for conduction. More free electrons means a larger current so a better conductor, meaning lower resistance. Materials should effect resistance also because different materials have different amounts of free electrons. The more free electrons means better conductor so lower resistance. Resistance of different materials will vary. I predict that from my experiment my graph will have a straight diaganol line like this. Planning As we increase the length of the wire we will be measuring the voltage when the current is at 1amp. Using these results we will work out the resistance. We do this because we need to find out if the length of a wire effects the resistance of the wire. And from these results find out how we can reduce the resistance of the wire. When measuring we will have to be accurate and make sure that the crocodile clips on the wire are exactly in line with the right measurements. Even 1mm can change the results dramatically. We will also have to ensure that the wire is pulled taught because if its bent up a bit its not stretched out to its full length so are measurements will be wrong and could effect the experiment. We will also make sure that the current does not go over 1-amp. Because the prelim work showed us that after this amount the test will be unfair, and it will be impossible to ensure the results are valid. Because the sellotape melts, and the wire expands and looses shape. In order to get accurate results we will do three repeats of the experiment. Are results are more reliable then because we have three to look at so we know what the measurements should roughly be around and any major errors will stand out. Analysis From doing my experiment and looking at my results I found out that as the length of the wire increases, the resistance increases. This shows that my predictions were accurate as this is what I predicted. From looking at the graph I also notice that it is a straight diagonal line, which is how I predicted it to be. This shows it is directly proportional. As the length of the wire doubles there is double the chance that the electrons will get captured by the metal atoms. Therefore double the resistance. Double length=double resistance 10 20 30 40 50 60 70 80 90 100 gradient = up = ? across cm Evaluation I think my experiment worked well because my results were as I predicted them to be and I did a fair test. Also there wasnt any major errors. From looking at my graph I can see it is a straight diaganol line just as I predicted. This shows it is directly proportional. To imrove my experiment and get more accurate results I could nail or solder the wire down to the ruler. This way it is more secure than the sellotape and it cant move out of position. Instead of using crocodile clips, as these could put a kink in the wire. I could use a knife edge or something metal to just touch the wire, as this is a conductor so still allows a current to flow through. I think I have enough results to be sure of what I wrote in my conclusion. I think this because my results prove the theory as length increases resistance increases. Show preview only The above preview is unformatted text This student written piece of work is one of many that can be found in our GCSE Electricity and Magnetism section.

Tuesday, January 21, 2020

Biometrics: The Science of Human Recognition :: Research Science Papers

Biometrics: The Science of Human Recognition As our society becomes more and more modernized so does our need for more sophisticated ways to identify people for who they really are. Biometrics is the science of human recognition. With this rapid movement to develop this new technology, many companies have come out with different ways to distinguish people. Some of these new forms of recognition include; retinal scanning, iris recognition, finger imaging, hand geometry, face recognition, voice recognition and signature recognition. These forms of distinguish people may be broken down into two basic categories: physical characteristics and personal traits. Physical characteristics are specific to each person. A physical characteristic is as unique as a person’s DNA code. A personal trait is a ‘style’ that is often unique to each person. The only problem with the recognition of this ‘style’ is that it may often change as a person grows and matures. Retinal scanning falls into the category of scanning for physical characteristics. It is performed by bouncing a laser beam off the cornea, which then absorbs specific frequencies of light according to that person’s specific cornea. The light that is not absorbed bounces back into the machine and is then read. The machine is able to recognize the unabsorbed frequencies of light as, Frank Turco. Another new physical biometrics system is iris recognition. Iris recognition is similar to retinal scanning. The colored area of the eye that surrounds the pupil has many lines randomly placed. These lines are specific to each individual; like a barcode is to a product. Again, a laser scans the eye and recognizes the bars of the iris as a person. Amazing isn’t it? Iris canning tends to be more ‘user friendly’ because you don’t need to be as close to the machine when it is scanning your iris. You may be up to nine inches away, where as with retinal scanning you may only be one to two inches away. The reason iris scanning is more "user friendly" is because when utilized by the public many communicable diseases may be passes along by the machine because of it close contact with the person. Face recognition is similar to the way we recognize people. A computer would be utilized to take a photo of each person and then analyze it. The computer's analysis of the photo would use facial geometry to recognize each person. Biometrics: The Science of Human Recognition :: Research Science Papers Biometrics: The Science of Human Recognition As our society becomes more and more modernized so does our need for more sophisticated ways to identify people for who they really are. Biometrics is the science of human recognition. With this rapid movement to develop this new technology, many companies have come out with different ways to distinguish people. Some of these new forms of recognition include; retinal scanning, iris recognition, finger imaging, hand geometry, face recognition, voice recognition and signature recognition. These forms of distinguish people may be broken down into two basic categories: physical characteristics and personal traits. Physical characteristics are specific to each person. A physical characteristic is as unique as a person’s DNA code. A personal trait is a ‘style’ that is often unique to each person. The only problem with the recognition of this ‘style’ is that it may often change as a person grows and matures. Retinal scanning falls into the category of scanning for physical characteristics. It is performed by bouncing a laser beam off the cornea, which then absorbs specific frequencies of light according to that person’s specific cornea. The light that is not absorbed bounces back into the machine and is then read. The machine is able to recognize the unabsorbed frequencies of light as, Frank Turco. Another new physical biometrics system is iris recognition. Iris recognition is similar to retinal scanning. The colored area of the eye that surrounds the pupil has many lines randomly placed. These lines are specific to each individual; like a barcode is to a product. Again, a laser scans the eye and recognizes the bars of the iris as a person. Amazing isn’t it? Iris canning tends to be more ‘user friendly’ because you don’t need to be as close to the machine when it is scanning your iris. You may be up to nine inches away, where as with retinal scanning you may only be one to two inches away. The reason iris scanning is more "user friendly" is because when utilized by the public many communicable diseases may be passes along by the machine because of it close contact with the person. Face recognition is similar to the way we recognize people. A computer would be utilized to take a photo of each person and then analyze it. The computer's analysis of the photo would use facial geometry to recognize each person.

Sunday, January 12, 2020

Black People and Grandfather Essay

8. How can the dream at the end of the story be related to the major incidents that precede it? The dream at the end of the story is about the circus with his grandfather. He refused to laugh at the clowns no matter what they did. There is a relationship between clowns at circus and the black boy in battle royal. They are forced to entertain the white man and are treated as if they are no better than animal. The seemingly endless series of envelopes implies that inequality still continue for a long time until black man fall of weariness and white society will continue to create clowns for their entertainment. 9. Given the grandfather’s advice, explain how â€Å"meekness† can be a â€Å"dangerous activity† and a weapon against oppression. In the death bed the grandfather told his son as well as his grandson keep up a good fight. â€Å"Live with your head in the lion’s mouth†, the grandfather want his son to prepare for himself a mask of meekness, overcome white persons with yeses, underline them with grins, agree them to death and destruction. This meekness is considered as dangerous activity because their family as well as many black men in recent society is controlled and oppressed by the white man. Becoming the white’s favorite is the only way to survive. However meekness is not the same as surrender, it seems to be a shield to conceal a deeper revolutionary spirit. The grandfather bequeathed to his grandson not only strategy to live with â€Å"the lion† but also a weapon against oppression.

Saturday, January 4, 2020

Overview of OLED Technology

OLED stands for organic light-emitting diode and its cutting edge technology results from many innovations in display monitors, lighting, and more. As the name suggests, OLED technology is the next-generation advance of regular LEDs and LCDs, or liquid crystal displays. LED Displays Closely related LED displays were first introduced to consumers in 2009. LED television sets were much thinner and brighter than their predecessors: plasmas, LCD HDTVs, and, of course, the humongous and outdated CRTs, or cathode-ray tube displays. OLED displays were introduced commercially a year later, and allow for even thinner, brighter, and crisper displays than LED. With OLED technology, completely flexible screens that can fold or roll up are possible. Lighting OLED technology is exciting because it is a viable and functional innovation in lighting. A lot of OLED products are light panels whose large areas diffuse lighting, but the technology lends itself well to different applications like the ability to change shape, colors, and transparency. Other benefits of OLED lighting compared to traditional alternatives includes energy efficiency, and the lack of poisonous mercury. In 2009, Philips became the first company to manufacture an OLED lighting panel called Lumiblade. Philips described the potential of their Lumiblade as thin (less than 2 mm thick) and flat, and with little heat dissipation, Lumiblade can be embedded into most materials with ease. It gives designers almost limitless scope to mold and meld Lumiblade into everyday objects, scenes and surfaces, from chairs and clothing to walls, windows and tabletops. In 2013, Philips and BASF combined efforts to invent a lighted transparent car roof. It will be solar powered, and will turn transparent when switched off. Thats just one of many revolutionary developments possible with such state-of-the-art-tech. Mechanical Functions and Processes In the simplest of terms, OLEDs are made from organic semiconductor materials that emit light when an electrical current is applied. OLEDs works by passing electricity through one or more incredibly thin layers of organic semiconductors. These layers are sandwiched between two charged electrodes–one positive and one negative. The â€Å"sandwich† is placed on a sheet of glass or other transparent material which, in technical terms, is called a â€Å"substrate†. When current is applied to the electrodes, they emit positively and negatively charged holes and electrons. These combine in the middle layer of the sandwich to create a brief, high-energy state called â€Å"excitation†. As this layer returns to its original, stable, â€Å"non-excited† state, the energy flows evenly through the organic film, causing it to emit light. History OLED diode technology was invented by researchers at the Eastman Kodak company in 1987. Chemists Ching W. Tang and Steven Van Slyke were the principal inventors. In June 2001, Van Slyke and Tang received an Industrial Innovation Award from the American Chemical Society for their work with organic light-emitting diodes. Kodak released several of the earliest OLED-equipped products, including the first digital camera with a 2.2-inch OLED display with 512 by 218 pixels, the EasyShare LS633, in 2003. Kodak has since licensed its OLED technology to many companies, and they are still researching OLED light technology, display technology, and other projects. In the early 2000s, researchers at Pacific Northwest National Laboratory and the Department of Energy invented two technologies necessary to make flexible OLEDs. First, Flexible Glass an engineered substrate that provides a flexible surface, and second, a Barix thin film coating that protects a flexible display from harmful air and moisture.