Nitroglycerin

Nitroglycerin (NG), also known as nitroglycerine, trinitroglycerin, trinitroglycerine, or nitro, is more correctly known as glyceryl trinitrate or more formally: 1,2,3-trinitroxypropane. It is a heavy, colorless, oily, explosive liquid most commonly produced by treating glycerol with white fuming nitric acid under conditions appropriate to the formation of the nitric acid ester. Chemically, the substance is an organic nitrate compound rather than a nitro compound, but the traditional name is often retained. Since the 1860s, nitroglycerin has been used as an active ingredient in the manufacture of explosives, mostly dynamite, and as such it is employed in the construction, demolition, and mining industries. Similarly, since the 1880s, it has been used by the military as an active ingredient, and a gelatinizer for nitrocellulose, in some solid propellants, such as Cordite and Ballistite.

Nitroglycerin is also a major component in double-based smokeless gunpowders used by reloaders. Combined with nitrocellulose, there are hundreds of (powder) combinations used by rifle, pistol, and shotgun reloaders.

For over 130 years, nitroglycerin has been used medically as a potent vasodilator to treat heart conditions, such as angina pectoris and chronic heart failure. Though it was previously known that these beneficial effects are due to nitroglycerin being converted to nitric oxide, a potent vasodilator, it was not until 2002 that the enzyme for this conversion was discovered to be mitochondrial aldehyde dehydrogenase.[2] Nitroglycerin is available in sublingual tablets, sprays, and patches.[3] Other potential suggested uses include adjunct therapy in prostate cancer.

Glyceryl trinitrate

Glyceryl trinitrate (GTN) is an alternative name for the chemical nitroglycerin, which has been used to treat angina and heart failure since the experiments of William Murrell were widely reported in 1879. Despite this history, the mechanism of nitric oxide (NO) generation from GTN and the metabolic consequences of this bioactivation are still not entirely understood.

It is useful in decreasing angina attacks, perhaps more so than reversing angina once started, by supplementing blood concentrations of nitric oxide, also called endothelium-derived relaxing factor, before the structure of the nitric oxide as the responsible agent was known. This led to the development of transdermal patches of glyceryl trinitrate, providing 24-hour release. However the effectiveness of glyceryl trinitrate is limited by development of tolerance/tachyphylaxis within 2–3 weeks of sustained use. Continuous administration and absorption (such as provided by daily pills and especially skin patches) accelerate onset of tolerance and limit the usefulness of the agent. Thus glyceryl trinitrate works best when used only short term, pulse dosing. Glyceryl trinitrate is useful for acute myocardial infarction (heart attack) and pulmonary edema,[citation needed] again working best if used quickly, within a few minutes of symptom onset, as a pulse dose.[citation needed] It may also be given as a sublingual or buccal dose in the form of a tablet placed under the tongue or a spray into the mouth for the treatment of an angina attack.

Silver nitrate

Silver nitrate is an inorganic compound with chemical formula AgNO₃. This compound is a versatile precursor to many other silver compounds, such as those used in photography. It is far less sensitive to light than the halides. It was once called lunar caustic because silver was called luna by the ancient alchemists, who believed that silver was associated with the moon.
In solid silver nitrate, the silver ions are three-coordinated in a trigonal planar arrangement

Silver nitrate can be prepared by reacting silver, such as a silver bullion or silver foil, with nitric acid, resulting in silver nitrate, water, and oxides of nitrogen. Reaction byproducts depend upon the concentration of nitric acid used.

3 Ag + 4 HNO
3(cold and diluted) → 3 AgNO
3 + 2 H
2O+ NO

Ag + 2 HNO
3(hot and concentrated) → AgNO
3 + H
2O + NO
2

This is performed under a fume hood because of toxic nitrogen oxide(s) evolved during the reaction.

Nitride Electronic NeXt Generation Technology

http://www.darpa.mil/Our_Work/MTO/Programs/Nitride_Electronic_NeXt-Generation_Technology_(NEXT).aspx

OLED

An OLED (organic light-emitting diode) is a light-emitting diode (LED) in which the emissive electroluminescent layer is a film of organic compound which emits light in response to an electric current. This layer of organic semiconductor is situated between two electrodes. Generally, at least one of these electrodes is transparent. OLEDs are used to create digital displays in devices such as television screens, computer monitors, portable systems such as mobile phones, handheld games consoles and PDAs. A major area of research is the development of white OLED devices for use in solid-state lighting applications.

There are two main families of OLED: those based on small molecules and those employing polymers. Adding mobile ions to an OLED creates a light-emitting electrochemical cell or LEC, which has a slightly different mode of operation. OLED displays can use either passive-matrix (PMOLED) or active-matrix addressing schemes. Active-matrix OLEDs (AMOLED) require a thin-film transistor backplane to switch each individual pixel on or off, but allow for higher resolution and larger display sizes.
An OLED display works without a backlight. Thus, it can display deep black levels and can be thinner and lighter than a liquid crystal display (LCD). In low ambient light conditions such as a dark room an OLED screen can achieve a higher contrast ratio than an LCD, whether the LCD uses cold cathode fluorescent lamps or LED backlight.

What are 1G, 2G, 3G and 4G networks ?

The "G" in wireless networks refers to the "generation" of the underlying wireless network technology. Technically generations are defined as follows:

1G networks (NMT, C-Nets, AMPS, TACS) are considered to be the first analog cellular systems, which started early 1980s. There were radio telephone systems even before that. 1G networks were conceived and designed purely for voice calls with almost no consideration of data services (with the possible exception of built-in modems in some headsets).

2G networks (GSM, CDMAOne, D-AMPS) are the first digital cellular systems launched early 1990s, offering improved sound quality, better security and higher total capacity. GSM supports circuit-switched data (CSD), allowing users to place dial-up data calls digitally, so that the network's switching station receives actual ones and zeroes rather than the screech of an analog modem. 

2.5G networks (GPRS, CDMA2000 1x) are the enhanced versions of 2G networks with theoretical data rates up to about 144kbit/s. GPRS offered the first always-on data service.

3G networks (UMTS FDD and TDD, CDMA2000 1x EVDO, CDMA2000 3x, TD-SCDMA, Arib WCDMA, EDGE, IMT-2000 DECT) are newer cellular networks that have data rates of 384kbit/s and more.
The UN's International Telecommunications Union IMT-2000 standard requires stationary speeds of 2Mbps and mobile speeds of 384kbps for a "true" 3G.

4G technology is mainly a marketing buzzword at the moment. The ITI has taken ownership of 4G, bundling into a specification known as IMT-Advanced. The document calls for 4G technologies to deliver downlink speeds of 1Gbps when stationary and 100Mbps when mobile, roughly 500-fold and 250-fold increase over IMT-2000 respectively. Unfortunately, those specs are so aggressive that no commercialized standard currently meets them.

Historically, WiMAX and Long-Term Evolution (LTE), the standard generally accepted to succeed both CDMA2000 and GSM, have been marketed and labeled as "4G technologies," but that's only partially true: they both make use of a newer, extremely efficient multiplexing scheme (OFDMA, as opposed to the older CDMA or TDMA), however, WiMAX tops at around 40Mbps and LTE at around 100Mbps theoretical speed. Practical, real-world commercial networks using WiMAX and LTE range between 4Mbps and 30Mbps. Even though the speeed of WiMAX and LTE is well short of IMT-Advanced's standard, they're different than 3G networks and carriers around the world refer to them as "4G". Updates to these standards -- WiMAX 2 and LTE-Advanced, respectively -- will increase througput, but neither has been finalized yet.

Touchscreens or Human Machine Interface (HMI)

A touchscreen is an electronic visual display that the user can control through simple or multi-touch gestures by touching the screen with one or more fingers. Some touchscreens can also detect objects such as a stylus or ordinary or specially coated gloves. The user can use the touchscreen to react to what is displayed and to control how it is displayed (for example by zooming the text size).

The touchscreen enables the user to interact directly with what is displayed, rather than using a mouse, touchpad, or any other intermediate device (other than a stylus, which is optional for most modern touchscreens).

Touchscreens are common in devices such as game consoles, all-in-one computers, tablet computers, and smartphones. They can also be attached to computers or, as terminals, to networks. They also play a prominent role in the design of digital appliances such as personal digital assistants (PDAs),satellite navigation devices, mobile phones, and video games and some books.

The popularity of smartphones, tablets, and many types of information appliances is driving the demand and acceptance of common touchscreens for portable and functional electronics. Touchscreens are found in the medical field and in heavy industry, as well as for automated teller machines (ATMs), and kiosks such as museum displays or room automation, where keyboard and mouse systems do not allow a suitably intuitive, rapid, or accurate interaction by the user with the display's content.

There are different types of touch screen

Resistive-The resistive touchscreen consists of a flexible top layer made of Polyethylene (PET) and a rigid bottom layer made of glass. Both the layers are coated with a conducting compound called Indium Tin Oxide (ITO) and then spaced with spacers. While the monitor is operational, an electric current flows between the two layers. When a touch is made, the flexible screen presses down and touches the bottom layer. A change in electrical current is hence detected and the coordinates of the point of touch is calculated by the controller and parsed into readable signals for the operating system to react accordingly.   

                                     

Capacitive – he Capacitive Touchscreen Technology is the most popular and durable touchscreen technology used all over the world at most. It consists of a glass panel coated with a capacitive (conductive) material Indium Tin Oxide (ITO). The capacitive systems transmit almost 90% of light from the monitor. Some of the devices using capacitive touchscreen are Motorola Xoom, Samsung Galaxy Tab, Samsung Galaxy SII, Apple’s iPad. There are various capacitive technologies available as explained below.

 

Surface-Capacitive screens, in this technique only one side of the insulator is coated with a conducting layer. While the monitor is operational, a uniform electrostatic field is formed over the conductive layer. Whenever, a human finger touches the screen, conduction of electric charges occurs over the uncoated layer which results in the formation of a dynamic capacitor. The computer or the controller then detects the position of touch by measuring the change in capacitance at the four corners of the screen.

In the Projected-Capacitive Touchscreen Technology, the conductive ITO layer is etched to form a grid of multiple horizontal and vertical electrodes. It involves sensing along both the X and Y axis using clearly etched ITO pattern.

Infra red – works with small infra red LED’s mounted around the outer edges of the glass front and basically divides the surface of the screen into small squares, making it extremely accurate. You can also use a stylus or have gloves on to make this work as it does not require a conductor, your finger, to make it work. In the Infrared Touchscreen Technology, an array of X- and Y- axes are fitted with pairs of IR Leds and photo detectors. The photo detectors detect any change in the pattern of light emitted by the Leds whenever the user touches the monitor/screen.

Surface Acoustic Wave (SAW) – are the most sensitive of the touch screens as it works by sending an ultrasonic wave across the screen, when the screen is touched the ultrasonic beam is altered and the information is sent to the touch controllerThe Surface Acoustic Wave Touchscreen technology contains two transducers (transmitting and receiving) placed along the X-axis and Y-axis of the monitor’s glass plate along with some reflectors. The waves propagate across the glass and are reflected back to the sensors.  When the screen is touched, the waves are absorbed and a touch is detected at that point. These reflectors reflect all electrical signals sent from one transducer to another. This technology provides excellent throughput and image clarity.

The Plural Touch Technology..!!

The plural touch technology or the Multi touch is a variant of the touchscreen technology which can detect two or more touches over its display area at the same time. Some of the common functionalities that require multitouch interface are zooming in, zooming out, rotating objects, panning through a document, virtual keyboard, etc. Multi touch Applications  technology are found in smart phones like iPhone, Samsung Galaxy, Nokia N8, Nexus S, Microsoft Touchtable, Apple’s iPad and many more.