Difference Between DVD-R and DVD+R

In today's advanced technological world, the term 'DVD' is not something that needs to be explained. Most people not only know about DVDs, but also use them in their everyday lives. Though used so very often, very few people know the actual difference between DVD-R and DVD+R, which are formats of Digital Versatile Discs(DVDs). When it comes to the difference between DVD-R and DVD+R, a majority of people think that the functions and technologies used in these discs would be much different. However, you need to know that there is not much of a difference between these two data storage mediums.

The 'R' after the plus or minus indicates 'recordable', which means that the disc can be written upon, but only once. If you have an 'RW' after the plus or minus sign, it indicates a 'rewritable' disc, which means that the disc can be rewritten up to 1,000 times. There is no difference between DVD-R and DVD+R in terms of the storage capacity they provide. A single layer DVD of both formats has a capacity of 4.7 GB, and a dual layer DVD has a storage capacity of 8.5 GB. Read more on different DVD formats.What is the Difference Between DVD-R and DVD+R?
Ownership of the DVD Formats
DVD-R and DVD+R are two contending technologies which employ different formats. Each of these formats is formally sanctioned and backed up by their individual forums. These licensing forums comprise of a particular number of companies. A company named 'Pioneer' was responsible for the advent of the DVD-R format which is based on the same technology as a CD-R. The DVD-R format is backed up by the 'DVD Forum' which was established by companies such as Mitsubishi, Sony, Hitachi, and Time Warner. It is believed that Sony Corporation took the initiative of developing the DVD+R format. This format is also no different from the CD-R. The DVD+R format is backed up by the 'DVD+RW Alliance'. This authorizing entity comprises of member companies which include Sony Corporation, Yamaha Corporation, Philips, Dell, and some others.Technology Used in the DVD Formats
The primary divergence amongst these two optical data storage discs is the inherent technology which is normally unobtrusive to the user. DVD-R employs the Land Pre Pit (LPP) technology for tracking and controlling the speed, whereas DVD+R utilizes an advanced ADdress In Pregroove (ADIP) functionality which makes the operation more precise at higher speeds. When it comes to the technology in DVD-R and DVD+R formats, the latter one uses a more robust error management technology than that employed in the former. The DVD+R format also employs more precise session linking methods which contribute to fewer damaged discs than the DVD-R format.Finalization of DVD-R and DVD+R
Another significant point of difference between DVD-R and DVD+R is that a DVD-R can be used in only one session for writing, while a DVD+R can be used in multiple sessions. In simple terms this just means that once you have used a DVD-R for writing data, it cannot be used again to write anymore data, even if there is space remaining on the disc. In case of a DVD+R, multiple sessions are allowed, meaning you can write 2GB in one session and still use the disc to write more data, till the entire capacity of the disc is used. In technical terms, this is called finalization of the disc. DVD-Rs finalize after a single burn, while DVD+Rs allow you the option of creating a 'multisession disc' instead of finalizing after the first burn. 'Multisession discs', however, may not be compatible with all players and DVD drives.Compatibility with DVD Players
The most significant aspect to consider about the difference between DVD-R and DVD+R formats is that the former one was developed first. This means that almost every DVD player or burner is compatible with DVD-R discs. So if you are not sure about where the disc is going to be used, it is recommended to store data on a DVD-R disc, as it can be played on most DVD players. You also need to take in mind that along with the compatibility factor, DVD+R discs are a bit more expensive that DVD-R discs. Read more on:

• DVD Recorders
• Portable DVD Players

There is no physical difference between these two discs. The only time you will possibly ever come to know a difference between DVD-R and DVD+R discs is if you insert a DVD+R in a drive that is only compatible with DVD-R discs. If you want to play both types of discs on a single DVD drive, you need to purchase a hybrid DVD drive which is generally marked as DVD±R. If you are thinking of DVD-R vs DVD+R, which is better depends on the technology you are looking for. DVD+Rs are more expensive, and even though they may be superior to DVD-Rs, they will not work on all players. DVD-Rs are a safer bet, are cheap, and will work on all players, though they may lack some minor features of DVD+Rs. The choice is yours!

GSM Vs CDMA

GSM is an acronym for Groupe Special Mobile, which has now been changed to Global System for Mobile Communication. CDMA refers to Code Division Multiple Access. The working of GSM and CDMA is very different. But the end result, after the implementation of the two technologies, is highly similar and matching in many ways. This article will try to highlight the subtle differences between the two technologies.GSM vs CDMA Technology

GSM is a very straight forward standard, whereas, CDMA is somewhat complicated. The key difference between the two is that GSM is a standard and CDMA is a technology, but GSM has attained some technology status over the years. So, what is the difference between GSM and CDMA? Read on to find out.GSM Explained
GSM is a 'cellular' technology, that is, the entire coverage area is divided into various hexagonal shaped cells (hence the popular name 'cell phones'). Every cell has a corresponding network tower, which serves the mobile phones in that cellular area. For example: Imagine a honeycomb on a tree in a hexagonal shaped garden. The garden has many flowers. The honeybees collect the nectar from the flowers, and deposit it in the honeycomb. Your mobile phones are like the flowers, the network tower is like honeycomb, and the bees are the signals.CDMA Explained
As the name suggests (Code Division Multiple Access), there are many devices which use the same spread spectrum (hence multiple access). There is one physical channel, and a special code for every device in the coverage network. Using this code, the signal of the device is multiplexed, and the same physical channel is used to send the signal (the codes may or may not change). For example: There is a street on which many buses ply. Obviously, the bus will have many commuters, and they will have to buy the tickets to travel on the bus. In CDMA, the commuter is like your mobile phone, the tickets are your codes, the bus is a multiplexed carrier signal, and the street is the spread spectrum.GSM vs CDMA Comparison
Call Quality: This is an area where CDMA scores substantially over GSM. Statistics are hugely in favor of CDMA. Various factors such as echoes, call dropping, or voice distortion are almost non-existent in CDMA, whereas in GSM, there is a high probability of errors. To give you an analogy, the bus on the street will continue to ply even when it's full, but if the honeycomb has reached full capacity, the honey cannot be deposited.GSM vs CDMA Call Qality Score: CDMA scores. Goal count 0-1.Carriers: GSM is one up on CDMA as far as carriers are concerned. The law requires CDMA carriers to provide handsets to users, for which the users cannot change their carriers. Whereas, GSM users can change their carriers whenever they want.GSM vs CDMA Carriers Score: GSM scores. Goal count 1-1.Network: It's an on-going battle between the two. Both the technologies are continuously improving the qualities of their network and adding various aspects to it as well.GSM vs CDMA Network Score: Both score. Goal count 2-2.Worldwide: There is a special number that every GSM compatible device in the world can call in case of an emergency. That number is 112. But in CDMA, this cannot be implemented because of certain technological limitations.GSM vs CDMA Worldwide Score: GSM scores. Goal count 3-2Battery Life: GSM, being a relatively simpler technology, uses less amount of cell phone battery than CDMA.GSM vs CDMA Battery Life Score: GSM scores. Goal count 4-2Coverage: GSM and CDMA, both have similar network coverage areas. They are present almost everywhere. The service providers of both technologies are striving hard to cover whatever inches that are left.GSM vs CDMA Coverage Score: Both score. Goal count 5-3Speed: Both GSM and CDMA are rapidly improving their capabilities in this regard. Both have introduced 3G mobile phones in their fold. Both are competing to gain space in this area.GSM vs CDMA Speed Score: Both score. Goal count 6-4Building Penetration: Again, in initial days, both technologies couldn't find building penetration, but after research in signaling systems, and through experience, service providers of both technologies have been able to give decent service to the mobile phones in buildings.GSM vs CDMA Penetration Score: Both score. Goal count 7-5GSM vs CDMA: Which is Better?

Both have their good qualities and bad qualities. GSM has some limitations where call quality is concerned, but GSM can be easily implemented and easily integrated into existing technology. Whereas, CDMA is little difficult to implement. By my estimation, GSM has an upper hand. So, the answer to the question, "GSM vs CDMA which is better?" is GSM. More on:

• History of Mobile Phones
• How Does a Mobile Phone Work
• GSM Mobile Phone Tracking System

Mobile communication has had a huge impact on modern day industry. GSM and CDMA technologies have unleashed mobile communication worldwide, and the technological competition between GSM vs CDMA has resulted in the improvement of services for the user.

Cellular Respiration in Plants

Cellular respiration, also referred to as oxidative metabolism, is a set of metabolic processes and reactions executed within the cell of an organism in order to convert the biochemical energy, derived from the nutrients, to adenosine triphosphate (ATP). ATP is a nucleotide which is the major source of energy for cellular reactions. The process revolves around catabolic reactions which facilitate oxidation of one molecule, with the reduction of the other. There are two types of cellular respiration, aerobic cellular respirationand anaerobic cellular respiration. Both, animals as well as plants, execute cellular respiration to produce energy. They use nutrients such as glucose, amino acids, and fatty acids to produce the energy. The common oxidizing agent in this process is molecular oxygen.What is Cellular Respiration in Plants?

It sounds confusing, as we already know that plants produce energy through the process of photosynthesis. It's true indeed, but that's not the only means of energy generation for plants. Cellular reaction in plants is totally opposite to photosynthesis, and more importantly, it does exist in plant life. There are four stages of cellular reaction in plants - glycolysis, transition reaction, the Krebs cycle, and electron transport chain. In order to understand how does cellular respiration occur in plants, we will have to get into the details of each of its stages.Glycolysis
The first stage of cellular respiration in plants, glycolysis, is the process wherein the glucose obtained from the food is chemically modified to form compound pyruvate. This process, which occurs in the cytosol of the cell, is carried out in the absence of oxygen. During this process, energy is released from glucose compounds in the form of 2 NADH molecules and 2 ATP molecules.Transition Reaction
Transition reaction, also known as pyruvate decarboxylation, is the second stage of cellular respiration in plants, wherein pyruvate is decarboxylated and added to Coenzyme A (CoA) in order to form Acetyl CoA. It is an important stage in the cellular respiration process as it forms a link between the metabolic pathways of glycolysis and the Krebs cycle.The Krebs Cycle
The next stage of cellular respiration in plants, the Krebs cycle, comprises of a series of steps which oxidize the Aceytl CoA molecule. Unlike glycolysis, the Krebs cycle requires oxygen for functioning. This aerobic process is catalyzed by enzymes. 2 complete turns of the Krebs cycle produce

• 4 carbon dioxide molecules
• 6 NADH molecules
• 2 ATP molecules
• 2 FADH2 molecules

Electron Transport Chain
The last stage of cellular respiration in plants is the electron transport chain, which produces the remaining 32-34 ATP. The chain comprises of electron-carrying proteins, based at the membrane of the mitochondrian. These proteins transfer electrons from one self to another. These electrons are finally added to oxygen, which is the final electron acceptor, along with the protons which leads to formation of water. In this process, ATP is produced by proton motive force, a store of potential energy created by the gradient that is formed when the protons move across the biological membrane. In simple words, electron transport chain triggers a gradient though which ATP is produced in a process known as chemiosmosis.

You may also prefer to read more on:

• Photosynthesis and Cellular Respiration
• Labeled Plant Cell Diagram and Functions

During photosynthesis the plant utilizes the energy from the sun and stores it in the form of bonds of glucose molecules, whereas during cellular respiration in plants, the glucose molecules stored in the plants are broken down to obtain the energy, in the presence of oxygen. Similarly, the plant can produce ATP in the absence of oxygen as well. This process is known as fermentation, but it's not as efficient as cellular respiration, and hence not so important.

Typhoon Vs Hurricane Vs Tornado

If you are confused about what typhoons, hurricanes and tornadoes are, you have landed on the right page. I will clarify all your doubts with a typhoon vs hurricane vs tornado comparison, which will highlight the essential distinction between them. All though these storm systems differ from each other, in one thing they are the same. They all wreck havoc in all the regions, that they pass through!

Before we go ahead and get into the typhoon vs hurricane vs tornado debate, let us define these terms.Typhoon: Definition
Typhoons, hurricanes and tropical cyclones are three different region specific names for the same kind of storm system! In short, they are one and the same phenomenon, although varying in intensity according to the place of origin and conditions.

So, a tropical cyclone a.k.a. typhoon, a.k.a. Hurricane is a peculiar storm system, which has a warm low pressure center, with an army ofthunderstorms around it. They have their origin near the equator, around 10 degrees away from it, in the sea. Read more on 'Typhoon Vs Hurricanes'.Tornado: Definition
Tornadoes are storm systems that form on land due to pressure differences. They are characterized by large rotating air columns, which are like funnels, that are connected with clouds at the top and land below. They move with phenomenal speeds, touching 300 mph on land before dissipating.Hurricane: Definition
As mentioned above, hurricane is the same as a typhoon, the only difference being the name. The same phenomenon is known as a typhoon and a hurricane in different regions, according to the local language.Typhoon Vs Hurricane Vs Tornado
There are more points of distinction in the typhoon vs tornado comparison, as they are two entirely different phenomena. Whereas, the points of distinction between tornado and hurricane are very few. Now that we have a rough idea about what these three things are, let us see the points of distinction between them.Typhoon Vs Hurricane Vs Tornado: Etymology
Let us start our typhoon vs hurricane vs tornado comparison with the difference in the etymology of these words. The word typhoon may have come from Mandarin word, 'Tai Feng', the Hakka phrase 'Tai Foong', the Cantonese phrase 'Dai Fung', which all mean 'Big wind', literally. Other possible origins of the word 'Typhoon' may be the Greek name for 'God of Winds', which was 'Typhon' or the Arabic, Hindi and Persian name 'Tufan'. The abundance and similarity of words for a typhoon is testimony to the fact that they have been a rampant menace, since forever!

The word 'Hurricane' comes from the Spanish word 'Huracan', meaning storm, which in turn was probably picked up from the Taino word from the Arawak language, spoken in Caribbean.

The word tornado comes from the Spanish word for thunderstorm called tronada, which in turn has its origin in the Latin word tonare, which means, 'to thunder'. The 'Twister' and cyclone are also used for tornadoes. That is because, it has its origin in the tropics. If a tropical cyclone occurs in the Northeast Pacific Ocean, the North Atlantic Ocean, east of the international dateline or in the South Pacific Ocean, east of 160 degree East latitude, it is called a 'Hurricane'. If the tropical cyclone occurs in the Northwest Pacific Ocean, on the west of the dateline, it is called a 'Typhoon'.Typhoon Vs Hurricane Vs Tornado: Origin and Occurrence
Let us discuss the origin mechanism and occurrence areas of typhoons, hurricanes and tornadoes. Let us briefly discuss each.

A hurricane and typhoon are the same thing. Just like the rose by any other name, would smell as sweet, a typhoon by any other name, would still be as deadly! In meteorological terminology, it is called a tropical cyclone. All storms like tropical cyclones are created due to severe differences in air pressure, caused due to temperature differences!

A tropical cyclone, like a hurricane or a tornado, is a type of storm system, which has closed wind circulation around a  central low pressure area, having their origin in the Ocean. The circulation is further fueled by heat released through moist air, which condenses as it rises. Warm air is lighter and therefore exerts low air pressure. Tropical cyclones are sustained by warm cores, which maintain the low pressure at center. They are created in the tropics every year and wreak havoc as they approach the inland coastal area. A recent example ishurricane Katrina, which was one of the most destructive tropical cyclones to ravage the North American coast land.

A tornado is a type of violent storm which occurs on land, again created by wind, moving from surrounding high pressure areas into low pressure center. It is a fiercely rotating air column, simultaneously in contact with land at the bottom and a sometimes funnel like cumuliform cloud at the top. Tornadoes are one of the deadliest and most destructive storm systems, particularly occurring all over the world, but more common in North America. So, the main difference in hurricane vs tornado comparison is, the fact that hurricanes originate in tropical seas, while tornadoes are created inland. Read more on, 'Differences Between Hurricane and Tornado'.Typhoon Vs Hurricane Vs Tornado: Facts
Here are some facts about hurricane and tornado facts which also illuminate the points of difference between the two phenomena.Hurricanes or Tornadoes are extremely powerful over the sea, causing tides and torrential rains around, but weaken and die out as they more over land, causing major damage in coastal areas. There is another point of similarity between hurricanes and typhoons, due to both being vortex based systems. Due to the 'Coriolis effect', hurricanes and typhoons in the northern hemisphere rotate counterclockwise and clockwise in the southern hemisphere. The central part or the eye of a typhoon could be as big as 370 kilometers! The hurricane season for the North Atlantic Ocean starts from 1st of June and continues up till November 30. Read more on,

• How are Tornadoes Formed?
• Tornado Life Cycle
• Causes of Tornados

The average wind speed of most tornadoes ranges from 40 - 110 miles per hour, but some of the most powerful ones attain wind speeds in excess of 300 miles per hour! There are three different types of tornadoes, which are landspout, multiple vortex tornado and waterspout. A tornado warning system is created with the use of weather radar and a chain of storm spotters. Tornado safety is in early warnings and announcement and in the construction of underground storm shelters. The most amount of tornadoes occur in a region in USA called 'Tornado Alley'. Tornado season begins in spring as it is a time of transition in temperatures. Read more on

• Interesting Facts About a Tornado
• Tornado Safety Tips
• Famous Tornadoes

Hope this typhoon vs hurricane vs tornado distinction has cleared your ideas about all the three terms. How much ever we develop our technology, we will never be able to tame nature completely. An early warning system is the only mechanism which can be our savior from nature's wrath!

Inventions of the 1800's

Ok, so you need to know that the 1800's have seen many many inventions. It is almost as if the light bulb in peoples mind was turned on when the year 1800 began. The world is a different place, both for the positive and the negative. We owe all the credit for that to the inventions of the 1800's.

So, be it Henry Bell, or Braille, Humphry Davy or Cyrus McCormick. They all got their minds and hands working on amazing inventions of the 1800's that have become a part of our day to day lives. Alright alright, I know you are probably skipping through my rants and introductions. So, let's just get to brass tacks, that is, the inventions of the 1800's.American Inventions of the 1800's
Before I get to the inventions that took place all over the world in the 1800's, here are the inventions of the 1800's in America.

• The "Box" telephone in 1876, by Alexander Graham Bell: Pioneering long distance oral communication.
• Electrical Light in 1879, by Thomas Edison: Thanks to his desire to "let there be light", we can work at night!
• The Morse Telegraph Key in 1844, by Samuel Morse and Alfred Vail: Pioneering speedy communication through the written word.
• Vacuum evaporation system in 1843, by Norbert Rillieux: Helping sugar cane plantation owners for sugar manufacturing.
• Sewing Machine in 1853, by Isaac Merritt Singer: Helped in having a stitch in time, to save nine!

These were a the inventions of the 1800's in America. I have to admit, they are very crucial inventions. But, let's move forward and look at the global picture. Here is the list of inventions (all over the world) in the 1800's.Inventions of the 1800's - Worldwide
These are the inventions that took place in the 1800's all over the world. I solemnly apologize to have missed out on any.

• The voltaic cell (Volta's pile) in 1800, by Alessandro Volta
• The first steam-powered pumping station in 1801
• Discovery of ultraviolet (UV) radiation in 1801, by Johann Wilhelm Ritter
• Jacquard loom in 1801, by Jacquard
• Dry cell battery in 1802, by Johann Wilhelm Ritter
• Modern electroplating in 1805, by Luigi Brugnatelli
• Electric carbon arc light in 1808, by Humphry Davy
• Gas-powered street lighting first appears in London in 1809
• Safety lamp for miners in 1815, by Humphry Davy
• Power loom in 1816, by Francis Lowell
• Stethoscope in 1816, by Rene Laennec
• Savannah - the first steamship across the Atlantic, in 1818
• Nicol Prism (type of polarizer) in 1820, by Nicol
• Thermocouple in 1821, by Seebeck
• Portland cement in 1824, by Joseph Aspin
• Metallic aluminium in 1825, by Hans Orsted
• Photography in 1827, by Niepce
• Achromatic microscope lens in 1827, by Amici
• Braille technique in 1829, by Louis Braille
• Electromagnetic motor in 1830, by Joseph Henry
• Safety fuse for explosives in 1831, by William Bickford
• Water Turbine in 1832, by Fourneyron
• 60/40 brass in 1832
• Analytical Engine in 1833 by Charles Babbage
• Electrical motor in 1837
• Telegraph in 1837
• Morse Code in 1838, by Samuel Morse
• Fuel cell in 1839, by William Grove
• Computer in 1840, by Charles Babbage
• Computer programs in 1840, by Lady Augusta Ada Byron Lovelace
• Use of wood for paper manufacturing in 1843
• Faraday effect on plane polarized light in 1845
• Cylinder printing press in 1846
• Stereoscope in 1849, by Brewster
• Bunsen burner in 1850, by Robert Bunsen
• Occulting telegraph in 1852, by Charles Babbage
• Petrol lamp in 1853
• Glider in 1853, by Sir George Cayley
• Halladay windmill in 1854
• Mercury Seismometer in 1855, by Luigi Palmieri
• Blast furnace for steel production in 1857, by William Kelly
• Synthetic Dye Factory in 1857, by William Perkin
• Photoheliograph device in 1858, by Warren de la Rue
• Cathode ray tube in 1859, by Plucker
• Internal combustion engine in 1860, by Lenoir
• Color photograph in 1861, by James Maxwell
• Motor running on solar power in 1861, by Auguste Mouchout
• TNT, trinitrotoluene in 1863 by Joseph Wilbrand
• Pasteurization process in 1863 by Louis Pasteur
• Blasting cap for detonating nitroglycerin in 1865, by Nobel
• Leclanche cell in 1866, by Leclanche
• Dynamite in 1867, by Alfred Nobel
• Fluorescent lamp in 1867 by Becquerel
• Wireline sounding machine in 1872, by William Thomson
• Four-stroke internal combustion engine in 1876, by Otto
• Phonograph in 1877 by Thomas Edison
• Remington Number 2 Typewriter in 1878
• Vaccine for Cholera in 1879
• Horizontal pendulum seismograph in 1880, by John Milne
• Interferometer in 1881
• Vaccine for anthrax in 1881
• Vaccine for Rabies in 1882
• Piezoelectricity in 1883, by Pierre Curie
• Turbine in 1884, by Charles Parsons
• Photographic film in 1885, by Eastman
• Pneumatic tyre in 1888, by John Dunlop
• Mass produced camera in 1888 by Kodak
• Vaccine for Tetanus in 1890
• Vaccine for diphtheria in 1890
• Rayon in 1891
• Prototype radio in 1892 by Nical Tesla
• Dewar flask in 1892, James Dewar
• Electric Hand drill in 1895, by Fein
• Hearing aid in 1895 by Miller Reese Hutchison
• The inverted pendulum seismograph in 1899 by Emil Wiechert
• Paper clip in 1899 by Johan Vaaler
• Three-lens multispectral camera in 1900, by Ives

The Process of Selective Catalytic Reduction for Reducing NOx Emissions

Selective catalytic reduction is a process used to reduce NOx emissions and air pollution control. This article explains the process of using SCR catalyst for nitrogen oxide emissions reduction.

The method of converting the harmful nitrogen oxide emissions (NOx) into harmless nitrogen gas and water, with the help of a catalytic reaction is called Selective Catalytic Reduction or SCR. The process of SCR involves the catalytic reaction of ammonia steam or ammonia air injected into the exhaust pipes containing NOx gases. The gases mix thoroughly and on passing through a catalytic bed, the NOx is reduced. The catalyst only promotes the reduction but is not affected by it. When urea is used as a reducing agent, the general by product of such a reaction is carbon dioxide.

The commercial viability of SCR technique is visible as it is found in large utility boilers, solid waste boilers and industrial boilers, diesel engines used in large ships, gas turbines, diesel locomotives, automobiles and power plants. The SCR catalyst technology is impressive as it is known to reduce the NOx emissions by nearly 70-95%.Working of the SCR catalyst in power plants
Power plants emit huge volumes of NOx as they derive their power from the combustion of fuels. With the new technique of SCR catalyst, these emissions can be reduced considerably. The mechanical process of SCR involves a reactor chamber with a catalyst bed containing catalyst modules and an ammonia injection grid system.

The ammonia air or steam is injected through the exhaust pipes containing the obnoxious NOx gases and on passing through the catalytic bed reduces the oxides of nitrogen into water and benign nitrogen gas. The reductants used by the SCR catalyst technique are aqueous ammonia, anhydrous ammonia or urea. All three have their limitations, but urea is the most commonly used reluctant. Thus the Selective Catalytic Reduction technique is known to reduce the harmful nitrogen oxides by nearly ten fold.Limitations of SCR catalyst in power plants
The most common limitation of SCR in power plants is the ammonia slip. This refers to the release of ammonia that has not been used in the chemical reaction of SCR. This happens when the required temperature levels necessary for the chemical reaction are not maintained or when there is too much ammonia injected into the system. Another common problem faced by the SCR catalyst technology in power plants is the emission of ammonium sulfate and ammonium bisulfate. With high requirements of ammonia to be injected for the chemical process, the excess ammonia combines with the sulfates in the air to form ammonium sulfate. This ammonium sulfate is known to cause shortness of breath, respiratory inflammation and coughing.How much NOx is removed by SCR catalyst?
It has been seen that with the use of proper SCR catalysts and system design, effective levels of more than 90% of NOx removal can be achieved. Several coal-fired boilers in Virginia and New Hampshire having the retrofit SCR catalyst systems are known to reduce the NOx levels by 60 to 65% during severe load timings. This figure is likely to be bettered to 85%. Even gas-fired utility boilers are known to be benefited by the SCR technique, where the emission levels achieved are more than 90%, thus not limiting the facility to large coal-fired boilers only. The SCR technique has known to reduce the emissions by up to 95% in gas turbines and power plants.

RFID Chip in Humans

RFID (Radio Frequency Identification) has been in existence for around 50 years, but very few of us are aware of having used it. RFID chip in humans is just an advancement of this technology. What is this technology used for and what are its pros and cons? We will deal with these questions and many other such queries in this article.

Many of us are not even aware of having used the RFID technology, at least once in our life time. Before starting off with explaining RFID chips in humans, we need to understand what is Radio Frequency Identification (RFID) technologyand what is it used for. Radio Frequency Identification technology is used for tracking goods, animals and even humans.

An RFID tag consists of two parts; an integrated circuit chip and an antenna. The antenna can identify the chip, even if it does not fall in its line of sight. Thus, RFID is a very effective way of detection. Now, just compare it to the bar code technology, used while selling products in a shopping mall. Each product is individually scanned for the bill to be made. Now, if RFID technology is used in the same place, then you can place all the products you wish to purchase in the same basket and all the products can be detected simultaneously. The billing of the products that you purchase can be in fact done very fast using this technology. Let us try to get into a little more detail as to how does the RFID technology work.

There are basically three types of RFID tags, active RFID tags, passive RFID tags and battery assisted passive RFID tags. An active RFID tag has an inbuilt battery to trigger the signals through the antenna. The passive RFID tags do not have any internal battery and need an external source to help trigger radio frequency signals through the RFID tag. The battery assisted passive RFID tag require a battery to start off the device but have significant amount of power to carry on the signal transmission process. Every RFID tag is given an unique number, similar to an user identification number. The processing device reads the tag and hence, finds out information about the article. This is the basic principle of working of devices using RFID technology.

Now, let us take a look at the RFID frequency. High frequency RFID systems, typically operate in the frequency ranges 850 MHz to 950 MHz and 2.4 GHz to 2.5 GHz. These devices can transmit over a range as high as 90 feet. Low frequency RFID systems have small ranges, somewhere around 6 feet and operate at a frequency of 30 Khz to 500 Khz. RFID is also sometimes referred to as Dedicated Short Range Communication (DSRC). Now without wasting anymore time in explaining what the RFID technology exactly is, let us take a look at the use of RFID chip in humans.
RFID Chip in Humans

The question is where did this idea come from. How would it prove to be convenient or by any means prove to be of some use to humans. Many people have contradictory opinions on the advantages and disadvantages of RFID implant in humans. Well the idea was simple. You can pay for services that you avail through the radio frequency identification chips.

Another important application is in the case of medicals. It can be used for storing a person's medical history. The medical history of a person can be stored in RFID chips. So, if a person is brought into a hospital under serious conditions, it would become extremely useful for the medical practitioner to know the patient's medical history, just by using a scanner that recognizes the RFID chip implanted in that particular person. This was the reason why the US Food and Drug Administration allowed implanting RFID chips in humans. These chips are as small as the grains of rice. The purpose was specifically for patients suffering from cardiovascular disease, diabetes, Alzheimer's disease and other such complex diseases. Many people have a wrong conception that the RFID chip implanted in a human contains data of the patient's medical history. This is however wrong. As already mentioned, the RFID chip just contains a unique number. It is through this number that the details of the patient's medical history can be retrieved from a master database.
Advantages and Disadvantages of RFID Chip in Humans

Just as in the case of any other technology, the RFID chip has its own share of pros and cons. Many people debate over the use of RFID chip in humans and consider that it will take away their privacy. We do not need to explain the uses or advantages of RFID chip in humans, as they have been explained in a much detailed manner in the last section. Let us rather take a look at what are its possible disadvantages. There are some complications that may arise because of an RFID chip implanted in a humans. These complications which may arise have in fact been marked by the US, Food and Drug Administration. These chips can cause problems when a patient is going through an MRI (Magnetic Resonance Imaging). One possible risk is the migration of the implanted transponder and in some  cases the chip may also cause adverse tissue reaction. For more information on the advantages and disadvantages of this entire technology, you can refer the articles, pros and cons of RFID technology and advantages and disadvantages of RFID technology.
RFID Cost

We are now probably at the right point to deal with the cost of RFID implant in humans. Well, first and foremost, the US government has made strict laws which says that no person or no organization can force an individual to get an RFID chip implanted. RFID chips nowadays cost somewhere around 50 cents. The RFID chip implant is done through a surgical procedure in which a chip of the dimension of 12 mm X 2.2 mm is implanted under the human skin.

RFID chips have been in use through a number of ways already. Product tracking, animal tracking, inventory control and passports are just a few of its application. However, mass implant of RFID chip in humans, will need to undergo some debates on privacy issues and medical issues, before it is used in a very large scale.