Acid Rain :: essays research papers fc

  Ã‚  Ã‚  Ã‚  Ã‚  Acid rain is a very big pollution problem in the world. It has killed fish and other aquatic life in many lakes and streams. It harms human health, disfigures monuments and erodes buildings, and, along with other pollutants, threatens forests. The story of acid rain can be compared to the plot of a science fiction movie. In the 1950s an invisible force begins to destroy lakes and rivers, killing trout and salmon. By the 1960s it is harming the waters of eastern Canada and the northeastern United States. High-altitude forests are beginning to fade away. City statues are gradually eaten away. The appearance from the damage of the aliens is starting to appear all over. Just as in science fiction movies, the authorities refuse to warn the alarmed citizens. Also, at the last moment the scientists figure away to destroy the aliens. Unfortunately, fiction and fact falls apart at this point. There is no quick remedy that will wipe out acid rain completely. (Pringle 1-2)   Ã‚  Ã‚  Ã‚  Ã‚  Coal was the main fuel of many industries in the early nineteenth century. Coal contains sulfur and when burning it, it will produce sulfur dioxide. When in the atmosphere, sulfur dioxide may be converted to sulfuric acid (Pringle 8). Acid rain is dispensed across the world by air currents. When attempting to fix local air pollution problems, the solutions actually added to acid rain problems on other parts of the world. High smoke stakes were developed to distribute pollutant acid-laden smoke higher in the atmosphere and spread it elsewhere (Merki 598). This was a quick remedy to a local problem, but harmed other parts of the world. Acid rain is a global problem because it more often than not, spreads over national borders instead of staying in a local spot.   Ã‚  Ã‚  Ã‚  Ã‚  There are several causes of acidification, and various mechanisms by which it may occur. Acid rain falling on water bodies has a direct affect. In areas where soils are acidic, runoff from the soil transports acidic water, which may also contain aluminum, into lakes and rivers. Soil acidification may be caused by acid rain, but other factors may also be involved. For example, if pasture reverts to coniferous acidic runoff even though the rain itself is not acidic. Salty rain leaches acid components out of the soil and transports them to the rivers. (Rivers 1)   Ã‚  Ã‚  Ã‚  Ã‚  The chemical content of acid rain is in itself dangerous to fish and other freshwater organisms.

Nat Turner’s Southampton Slave Revolt Essay -- Nat Turner’s Slave Rebe

  Ã‚  Ã‚  Ã‚  Ã‚  Nat Turner was a man with a vision that would change America forever. His vision may have not sounded right to the average person but to Nat Turner, he was on Earth to realize his vision. Nat Turner is the most famous and most controversial slave rebel in American history, and he remains a storm center of dispute("Fires of Jubilee" author Stephen B. Oates).   Ã‚  Ã‚  Ã‚  Ã‚  Nat Turner’s slave revolt may have not been the greatest way to solve the problem of slavery, but it did open many people's eyes. Slavery was an accepted practice in society but it was not a humane or kind thing. The cruel and unjust treatment by the slave masters in the 1800's led to Nat Turner's slave revolt, which in turn led to the abolitionist movement.   Ã‚  Ã‚  Ã‚  Ã‚  Nat Turner was born on October 2, 1800 in the small town of Jerusalem in Southampton, Virginia. Nat's mother Nancy was one of 400,000 native Africans brought to North America before 1808. While most of the Africans had come from West Africa, Nancy's was supposedly from in the North's Nile River country("Fires of Jubilee"). Folk chroniclers say that slave traders or warlike natives abducted Nancy when she was a teenager. She was thrust over to European slave traders and crammed on a disease infested slave boat headed to the New World("Fires of Jubilee"). Nancy's ship landed at Norfolk, Virginia around 1795. She then was herded more inland where slave traders exhibited her at several slave auctions. Around 1799 Nancy was brought by Benjamin Turner and her life on a plantation began. Not long after Nancy had arrived at the plantation, she married another slave whose name is unknown("Fires of Jubilee"). Their union produced Nathaniel "Nat" Turner. In Hebrew this name meant "the gift of God.† Nancy did not want to bring her young son up as a slave so she tried to kill him. The slave owners punished Nancy for trying this and shackled her for a lengthy period.   Ã‚  Ã‚  Ã‚  Ã‚  As Nancy watched Nat get a little older, she noticed that she had a special child. She was extremely proud of her young son Nat. Nat was bright, and quick to learn and he stood out from the rest of the children. In one instance, Nancy overheard a conversation Nat was having with some of his playmates. He was telling them of a story that had taken place long before he had been born, yet he told the story like he was there. Nancy asked young Nat "Did anyon... ...rocess of abolishing slavery. The climax of the steps was President Lincoln's "Emancipation Proclamation.† Nat Turner's slave revolt and the abolitionist movement really helped bring an end to the cruel and unjust reality of slavery. Without the Nat Turner slave revolt the abolitionist movement would have never come about. Some critics complain that the revolt was very violent and unnecessary, but so was slavery. The slave revolt opened America’s eyes to the ills of slavery and paved the way for less violent revolutions such as the Black Muslim uprising and the Civil Rights non-violence movement. Bibliography 1. Aptheker, Herbert; Nat Turner’s Slave Rebellion, Johnson and Williams Inc., New York, New York, 1921 2. Farina, Reggie; Nat Turner’s Rebellion, Snyder Publications, Chicago Publishing House, Chicago, Illinois, 1963 3. Friedman, Jesse; Nat Turner: Prophet, Visionary, Slave Revolt leader, Adu publishing inc., New York, New York, 1892 4. Gray, Thomas R.; The Confessions of Nat Turner, Thomas R. Gray publishing, Lucas and Denver printing, 1831 5. Oates, Stephen B.; Fires of Jubilee; Nobles, Turner and Smith, Los Angeles, California 1899

Porters Five Force Analysis for Paint Induatry

For a dominant paint manufacturing company which is spread allover India, local players act as a very huge threat to them. With a small place for factory and an effective distribution system the local players may pose themselves a huge competition for these nationalized companies. As the local players do not mind quality but sell products for cheap rates they grab more attention of middle class people in India who are of majority. But if the major company has a huge brand name with quality product and some marketing gimmicks they can lure customers even if they have high prices. Power of suppliers As said above the local players are more or less who started as suppliers for the big companies. As the required number of raw material are more in preparation of paint if these suppliers come together and start making end products the pose themselves as huge threats. Power of buyers As this being a competitive industry with multinational players, national players, local players the buyer has a lot of options to his disposal. Switching cost is also not high. The contractors and painters also play their role, as they will tend to buy from people who give them incentives. So the companies should always be on toes in retaining the existing buyers by some effective reward or marketing system. Availability of substitutes The likelihood of availability of substitutes in this industry is less. But the varieties of products are more. This is where big players have an edge over local players. With different kinds of paints available in market to manufacture all kind you need huge factories but the local players will have a small unit which basically manufactures not mare then a few variants. Competitive rivalry As mentioned before the rivalry is very high with n number of makers in the market and n number of takers in the market. If the construction industry is on a downward slope then it affects this industry a great deal.

The Definition of E-commerce

E-commerce is the buying and selling of products and services by both businesses and consumers over the Internet. Such practices have exploded over the last year as security has improved with more and more consumers now buying goods and services online. This coupled with the computer revolution of the late twentieth century has lead to e-commerce now becoming the buzzword of trade and industry as hundreds of companies are now moving online in an attempt to broaden their product range and direct contact with customers. Firstly we must understand why companies are being drawn towards selling their products online. An e-commerce site that is implemented well can significantly lower both order taking costs up front and also customer service after the sale has been made. For example being located on the Internet means that place does not enter into the marketing mix of an e-commerce company. As its customers will not visit the business, it means having a prominent high street location is no longer of importance; in fact a business can be set up in someone†s home (if space for storage allows!). Also when considering mail order companies there is no longer the need to endure the costs of designing, printing and sending out catalogues. These factors contribute to e-commerce companies being able to offer products at greatly reduced prices as overheads have been minimised. A company now has the ability to provide customers with a catalogue that has a far more extensive range than that of which any mail-order catalogue could provide. Recently Amazon have advertised that they currently offer more than 3 million books, to further their service they also give the customer the opportunity to read a description of every book supplied and also other titles buyers of the book have purchased. It is inconceivable to imagine all this information being provided in any catalogue that comes through the letterbox. So we now can see some of the benefits that firms encounter from locating on the web but what do the consumers get out of this? It is now far easier to collect market research and make reasonable comparisons as by using the Internet you have the ability to amass, analyse and control large quantities of specialised data. The Internet can give the opportunity for customers to try before they buy. For example the online record store Klik-Klik-Whirly-Bleep-Bleep gives the online shopper the opportunity to listen to any record before they buy it, an essential factor to regular purchasers of records and especially dj†s. There is also the potential of wider availability of hard-to-find products and wider selection of items due to the width and efficiency of the Internet. One such example being â€Å"Squaddies Online†, this company has developed its success by selling goods that are normal in everyday life in the United Kingdom but are sorely missed by those that are overseas for any great length of time. For instance amongst the current best selling items are Heinz Tomato Ketchup and HP Brown Sauce! The increase in the ability to undertake market research has inevitably led to the reductions in prices as more suppliers are able to compete in an electronically open market place. This increase in competition has lead to better quality and variety of goods through expanded markets and the ability to produce customised goods. When the motorbike company Dukati recently launched their online site they sold their stock within 31 minutes of opening with a popular feature being giving the customer the opportunity of designing the exact colour scheme of the bike. So far the benefits of e-commerce are outlined and you would be forgiven for immediately wanting to dream up your own way of becoming rich through the internet. But it is by no means plain sailing. Seven out of ten internet businesses located within the United Kingdom fail to trial their service before it is launched. Even then almost all are likely to have experienced problems and over a fifth are now experiencing significant customer service disruption as a result of sudden surges in demand or server overload. Hundreds of web sites and not just e-commerce services have been launched in the United Kingdom during 1999. The Pricewaterhouse Cooper group informs us on there website that this figure is set to explode to  £60 billion within the next three years. However market shares are going to be effected in ways previously unseen before through the failures of sites and service providers. Failure in e-commerce is not always going to be caused by poor products but rather by not building sites that are as efficient and usable as its competitors. For an e-commerce business to be successful it is essential that the sites are given thorough pilot tests so that faults can be found and also customer behaviour patterns can be learnt. It is possible that such a venture can take off as an amazing success however there is also the danger of overselling. This can cause potentially lethal consequences as if the server used is not big enough to cope with the demand then the site is likely to crash or be severly disrupted through overload. Indeed any e-commerce system should have some sort of early warning device to notify the programmers that there are problems as soon as possible. So far the e-commerce has only been covered in terms of the internet through use of the home computer. Digital television uses television to access a range of interactive services including e-mail and the internet. Once companies build websites to generate businesses they start to recognise the role the Internet could play in the communications process. However there are still worries that the Internet is still not receieving enough coverage in terms of those with access. However didgital television has the potential to cause a far greater impact. Digital television provides access to a larger target audience as its popularity is currently growing at an exponential rate. The large range of channels also means that communications can be tailored to suit the person viewing more effectively especially with the wide range of visual and audio devices at the sellers disposal. Security is not seen as the same potential mishap as on the internet as there aren†t fears hackers being able to break into sites and accessing personal information. By accessing the Open interactive service on digital television you are able to visit stores such as Next, Woolworths, WH Smiths and Dominos Pizza. All of which are firms that are highly reputable which will also give the customer confidence when using. However it is not such an easy options for companies as there is currently a high cost of entry when wishing to move into such ventures. Indeed currently companies are having to rely on the consumer having access to this technology E-commerce is growing at an explosive rate on the Internet. Before the end of this decade, millions of people will be buying, selling, bidding and advertising on a daily basis as the internet merges with other branches of the information highway. The new economies of scale that are evident for such companies drastically lower the cost of establishing and maintaining a successful company. It is vital that any business wanting to start up in e-commerce should continually examine the risks and opportunities created by such a venture. It is essential that designers make use of the technologies that are available. In the long-term the risks of lagging now are likely to exceed those of continuing with less then maximum adoption strategies. Currently the Internet does have its limitations that may not make it suitable for all ventures. However with the rate that technology is expanding the Internet will soon become â€Å"industrial strength† whereby it will be possible to comply with all requirements and safety regulations. This will also include what services can be accessed and by who. The emergence of Digital Television has also increased the significance of e-commerce as now even more people are able to purchase goods within a matter of seconds even if it is in a slightly different way. By encouraging e-commerce all sides will gain through lower prices and better quality. It is only a matter of time before e-commerce becomes an obvious part of our lives.

Obesity in Western Culture Essay

Within our constantly evolving and ever-changing Western world, what is deemed as being deviant has shifted and adapted to suit the norms and values of society at large. Thus, deviancy can be defined as behaviour that violates the normative rules, understandings or expectations of social systems. The issue of obesity has become increasingly prominent within Western society and is deemed as being deviant due to its wide unacceptance throughout society. In applying the ‘Functionalism’ perspective of deviance on obesity, the ways in which society attempts to handle and understand this issue is further outlined and explained. Obesity is a term used to describe body weight that is much greater than what is considered the healthy range. Individuals who are obese have a much higher amount of body fat than is healthy or recommended. Adults with a body mass index (BMI, calculated as weight in kilograms divided by height in meters squared) greater than 25 kg/m2 but less than 30 kg/m2 are considered overweight (Insel, Turner, Ross, 2009). The ways in which those who classify as ‘obese’ are perceived and portrayed by society are, within a Western society fixated on image and obsessed with reaching physical ‘perfection’, often negative and highly critical. The media plays a crucial role in shaping the idea’s and values our society holds. As we are constantly bombarded with images of ‘idealistically thin celebrities, it becomes evident that those who do not fit this normality are excluded from social acceptance and pressured into losing weight and fitting in. A recent article in the Sydney Morning Herald stated that; â€Å"while there was sympathy for underweight models because of possible eating disorders, those with overweight body shapes were blamed for not doing something to lose weight† (Gray, 2010). It is evident here that although there is some negativity urrounded with being ‘underweight’, super-thin models and celebrities continue to be represented as acceptable throughout the media, whereas those classified as ‘obese’ are rejected from mainstream society and blamed for not taking the initiative to lose weight. As we concentrate more on what is considered to be ‘physically attractive’, we lose sight of the various biological, genetic, and noncontrollable etiological factors (Puhl, Shwartz, Brownell, 2005) that relate towards obesity. Thus, negative stereotypes and stigmas are placed upon the obese, further strengthening heir label of deviancy. In a recent study conducted by Yale University, the perceived social consensus on attitudes toward obese people was tested. Three experiments were created towards educating the participants on the issue of obesity in hope of reducing the bias stereotypes and stigmas our society has successfully created towards the obese. (Puhl, Shwartz, Brownell, 2005). The study describes how the consensus attitude towards obesity prevents the reduction of stigmatizing and excluding the obese from mainstream society as people in general feel a sense of security and ‘approval’ in following the beliefs of the majority. Thus, if we as a society take greater acknowledgment in the causes of obesity and perhaps even empathize towards those labeled as obese; the idea of obesity as being a form of deviance could potentially shift throughout the long term. The ways in which the ‘obese’ are negative stigma held towards obesity by society at large. According to David F. Williamson of The New England Journal of Medicine (1999), it is crucial that doctors encourage greater weight loss towards obese patients as obese people are â€Å"twice as ikely to die from any cause as people of normal weight. † Society then not only recognizes obese people as being â€Å"obscene, lazy, slothful and gluttonous† (Adler, Adler 2000) but also as ill, and in a sense, ignorant towards the consequences of their poor state of health. As modern technology continues to develop and treatment options further increase, obesity becomes more and more deviant throughout society. Procedures such as ‘liposuction’ are becoming more available, with surgeries having increased 21 5 percent since 1992 (Naisbitt, Naisbitt, Philips 2001). Although ndergoing plastic surgery has not yet attained complete social acceptance, procedures such as liposuction reduce the consequence of the obese being labeled deviant due to their status. In contrast, the way obese people perceive and view themselves is largely impacted by the constant discrimination and criticism carried out by society at large. Although it can be said that in the presence of other obese people there is a greater sense of acceptance and understanding, the self-representation of obese people is generally negative and painful. According to an article on ABC news, one obese female stated hat â€Å"(you feel like) you have no right to exist as you are. Feeling as though this body is an outlaw body’ (Stark, 2004). The majority of obese people often view themselves as outsiders to the social norms of image and feel as though there is a ‘culture of blame’ (AN’, 2008) constantly against them. There have been studies undergone which illustrate the reluctance amongst obese patients to seek preventive health care services due to the embarrassment of their weight, and perhaps even the feeling of being criticized by physicians (Fontaine, Faith, Allison, & Cheskin cited in Puhl, Shwartz, Brownell, 2005). This clearly shows that obese people themselves are not content within their condition and recognize their deviant label within society. Although they inevitably feel the pressure to lose weight, the embarrassment of yet again being Judged and criticized by healthcare professionals prevents them from doing so. The Functionalist approach to deviance can be applied to obesity in many ways. Functionalism was developed by Emile Durkheim and illustrates how the institutes within society function and maintain social equilibrium. A functionalist analysis of eviance begins with looking at society as a whole rather than focusing on the individual. â€Å"It looks for the source of deviance in the nature of society rather than the biological explanations or psychological nature of the individual† (Covington, 1999). In this regard, applying functionalism to obesity becomes difficult as obesity is initially a personal health concern. Both biological and psychological aspects contribute towards obesity which then labels the individual as deviant, proving that rather than focusing on the nature of society at large for explanations on deviancy, it is equally ital to focus on the obese individual to understand their deviant label. Inevitably, this can be recognized as a weakness within the functionalist argument. In contrast, applying functionalism to obesity presents much strength in understanding why education have had to shift and develop in order to combat the obesity epidemic and create greater equilibrium within Western society. Australian schools have recognized the deviant nature of obesity, mainly due to its associated health risks, and have recently began enforcing healthy eating and exercise habits (Hareyan, 006). School systems have recognized that many families are unable to teach their children healthy habits, so have taken upon this role to maintain the social order within society. Alongside this, there has been a vast increase in weight-loss alternatives (rather than simply the gym, or perhaps surgery) to suit the modern, working individual. ‘Quick weight loss pills and detox diets are now more on the market than ever before and are available to anyone willing to pay. Functionalism revolves around creating solutions to maintain social order, and in regards to obesity, any actions have been taken as obesity is seen as a deviant act which disrupts the balanced functioning of society. In conclusion, obesity has been labeled as a deviant act within modern Western society as it violates what the consensus recognizes as ‘normal’ behaviour. It is increasingly less acceptable with those carrying the status left facing the consequences of social Judgment and exclusion. In applying the functionalist theory, the deviant nature of obesity can be further outlined and understood as a problematic issue within contemporary society.

Redemption in The Kite Runner Essay

It is only natural for humans to make mistakes, just like Amir in the novel The Kite Runner, but it is how the mistakes are resolved that will dictate ones fate. The main character of The Kite Runner, Amir, knows a thing or two about making mistakes. What he struggles with throughout the novel is finding redemption for those mistakes. Throughout all stages of Amir’s life, he is striving for redemption. Whether Amir is saying the wrong thing or hiding from a hurtful truth, he always finds new things he will have to redeem himself for. That is why redemption is a huge underlining theme in The Kite Runner. When Amir is a child, he feels his father blames him for his mother’s death and cannot love him. He does everything he can think of to try and make up for the mistakes he made in the past. Since Amir feels his father does not love him, he thinks of ways to make things right with him. Amir sees Baba as a perfect higher presence that he could never amount to. When the kite running competition comes around he takes this opportunity to prove to his father that he can be more of an â€Å"ideal† son to Baba, ultimately getting redemption for everything his father has not approved of. Amir sees Baba as a perfect father figure because everyone looks up to him. Amir could never live up to Baba’s expectations of him and that is where the theme of redemption comes to play between these two characters. Although Amir impresses his father by winning the kite running competition, he ends the day by hurting his best friend in a terrible way and one day he will have to find a way to make up for it. Amir and Hassan are two inseparable children, but their relationship is unusual because Hassan is Amir’s servant. Amir is never very nice to Hassan, but Hassan would never turn his back on Amir. This is evident when he says, â€Å"For you a thousand times over†. Amir makes a huge mistake one day by hurting Hassan and it takes a ver y long time for him to find a way to redeem himself. The kit running competition was supposed to be the best day of Amir’s life. He would win, and earn his dad’s unconditional love once and for all, but things are not always as they seem. Although Amir did win the competition, something went very wrong. Hassan will always have Amir’s back, until the day he dies he would do anything for him. When Amir cut the last Kite down from the sky, Hassan decided to run it. Assef and his two friends didn’t exactly want Hassan to bring the kite back to Amir. Amir is a very evil young boy and since Hassan would do anything for Amir, he refuses to hand the kite over to Assef. Hassan’s final act of bravery results in his rape and Amir’s next big mistake. Amir watches Assef and his friends rape Hassan, but he does nothing to help his friend. Amir goes many years knowing this information but never tells anyone, but what goes around comes around. When everything finally catches up with Amir, he is a grown man. Things in Amir’s life have finally settled down, but now the past is brought b ack up; he must go find redemption once more. Amir survived his childhood, made a good life for himself and marries a beautiful Afghan woman named Soraya. One thing Amir is deprived of in his life is the ability to have children. Amir’s inability to have children could possibly be looked at as coincidental or symbolic to him making amends for his past mistakes and misgivings. Amir receives a phone call from his father’s old friend Rahim Khan. Although Rahim is dying, he asks Amir to come visit him in Afghanistan. Amir soon realizes that the main reason Rahim Khan asked him to visit was not to see him before he died, but because Rahim wants to help Amir succeed in reaching his final redemption. Rahim Khan has known about the kite running competition for Amir’s entire life, and he has a way for him to try and set things right. Hassan, who is dead now, has a son, but he is an orphan boy. The Taliban has taken over Afghanistan and they killed Hassan and his wife in cold blood. Sohrab, who is Hassan’s son, has been taken by the Taliban as payment for the orphanage. Rahim Khan puts Amir up to the challenge of going to find Sohrab and giving him a proper home. He states, â€Å"I have a way to make things right again†. In order for Amir to redeem his past with Hassan, he must go and find Sohrab, who is the ultimate symbol of redemption in Amir’s life. Finding Sohrab was Amir’s greatest accomplishment, it was the ultimate redemption for all the evil and unjust things that have haunted his past. Amir fails to stand up for himself and others, as a child. As an adult, he redeems his uncourageous past by setting it right with the help of some very close family members. Amir goes through many stages in his life, but he always seems to be redeeming himself for something. Sometimes life seems to work out in the end, and the search for redemption may not always be easy, as witnessed in Amir’s case. However, a strong will and determination can help guide the road to redemption and possible forgiveness.

The Microwave Plasma Enhanced Engineering Essay

When diamond is mentioned, people will automatically believe about the cost that valued by the society. Why diamond, a type of gemstones, will be so much more than others? Diamond is non merely a shinny rock. It has a batch of great and alone belongingss such as highest hardness and thermic conduction of any bulk stuff. These belongingss determine the major industrial application of diamond in cutting and polishing tools. Besides, the optical feature is something that must be discuss in diamond. With highly stiff lattice, the optical features become important. However, diamond still can pollute by few types of drosss, such as B and N, which consequences in some colour for diamond. In this paper, a reappraisal of diamond will be presented.How diamond is madeNaturally, diamonds are formed at high force per unit area and high temperature conditions bing at deepnesss of 140-190 kilometer in the Earth mantle. They are bought near to Earth surface through volcanic eruptions by a magma, whi ch cools into pyrogenic stone known as kimberlites and lamproites. Figure 1shows a stage diagram of C. From Figure 1, diamond is stable at high force per unit areas and temperatures. Graphite, nevertheless, is the stable signifier of C under ordinary temperature and force per unit area conditions. One method of synthesising diamond is to subject graphite to conditions of about 55,000 ambiances and temperatures of about 2000 & A ; deg ; -C. However, even though C is non at the minimal energy province, it does non spontaneously convert from diamond to graphite. Since we know that diamonds are form at high force per unit area and high temperature. Research originally synthesis diamonds under same conditions, high force per unit area high temperature ( HPHT ) . Figure 1 Phase diagram for C. At sufficiently high temperatures and force per unit areas diamond is the stable. At lower temperatures and force per unit areas, black lead is the stable signifier. Under ordinary conditions for temperature and force per unit area, near 1 standard pressures and room temperature, diamond may be considered a metastable signifier of C. ( Reinhard ) The everyday belongingss of diamond such as hardness and high thermic conduction make it an of import new stuff in a broad scope of applications. However, the high cost of stuff production has limited the commercial used of diamond thin movies to a few applications. Today the engineering is able create artefactual diamond by chemical vapour deposition ( CVD ) . CVD is a method of bring forthing man-made diamond by making the fortunes necessary for C atoms in a gas to settle on a substrate in crystalline signifier. It is common to happen grammatical crystals with about equal development of ( 111 ) and ( 100 ) faces ( Figure 2 ) . ( DeVries ) Diamond grows by CVD frequently involves feeding changing sums of gases into a chamber, stimulating them and supplying conditions for diamond growing on the substrate. The gases include a C beginning and typically include H every bit good. However the sums used depends on the type of diamond being grown. In CVD of diamond, the factors driving cost include low reagent use, low deposition rates, high-energy ingestion, big thermic direction tonss at the substrate, and capital equipment costs. For successful consequence, diamond deposition depends on different chemical and conveyance procedures happening in the gas stage and on the surface. ( See Figure 4 for the ascertained forms of as-grown natural diamonds, high temperature high force per unit area ( HPHT ) grown synthetics and chemical vapor deposition ( CVD ) grown diamonds, including the measure patterns on the different faces ) Figure 2 Diamond crystals from CVD deposition. The largest dimension is about 20 jlm. ( DeVries ) All diamond CVD processes under a extremely energetic activation phase in the gas stage. It lead to two intents which are to disassociate the hydrocarbon precursor molecule into fragments that react more readily at the deposition surface and to disassociate molecular H to make a superequilibrium concentration of gas-phase H atoms. ( See Figure 3 for different technique of C dissolved in H vs. temperature ) Hot-filament reactors, microwave plasma reactors, DC arcjet reactors, and burning are most commonly energy used as diamond CVD reactors. These reactors have a few common characteristics and that ‘s why they are able to bring forth high quality diamond movies. They all have a big sum of energy, in the signifier of electrical or chemical free energy, is input to accomplish dissociation of molecular H and the hydrocarbon feedstock. Reasonably low force per unit areas are used to forestall three-body recombination of H to organize molecular H. High gas-phase temperature is produc ed in the activation zone, and inactive or active chilling is employed to keep a substrate temperature in the vicinity. However, they are different from the conveyance processes. Hot-filament and microwave plasma are dominated by diffusion which mean there is no thermic, speed, or concentration boundary bed. Linear gradients in temperature, speed, or species concentration between the excitement part ( hot fibril or plasma ball ) and the deposition surface in both reactors are frequently found. However, the disadvantage is growing rate is slow. DC arcjet CVD and burning is characterized by high speeds ; thin boundary beds in temperature, speed, and concentration are formed near the growing surface. In the followers, the item of each technique will be introduced. Figure 3 Differential solubility of C in H for different CVD diamond methods. Figure 4 Idealized morphologies of natural, HPHT-grown and CVD-grown diamonds. For the { 111 } and { 100 } faces characteristic orientations o f growing stairss are besides indicated. ( Nazare and Neves )High force per unit area and high temperature ( HPHT )Artificial Diamond is original made by high force per unit area and high temperature ( HPHT ) It is still widely used because of it ‘s comparatively low cost. It is typically processed under a force per unit area of 5GPa at 1500 & A ; deg ; C. There are two common systems ; Belt system and Bars system. In belt system, a immense hydraulic imperativeness with anvils and a ring molded construction are used. The upper and lower anvils supply the force per unit area burden to a cylindrical inner cell and a belt of pre-stressed steel sets confines the internal. Anvils serve as electrodes and supply electrical current to the compressed cell. A fluctuation of the belt imperativeness uses hydraulic force per unit area to restrict the internal force per unit area. Figure 5 is a conventional illustration of a belt system where diamond seeds are placed at the underside of the imperativeness. While the internal portion of imperativeness is heated, the liquefied metal dissolves the high pureness C beginning. The liquefied metal so transports to the diamond seeds and precipitates. Colorless diamond can be synthesized if the N is removed by blending little sum of Ti with the metal. ( International Diamond Lab ) Figure 5 aˆ?This is a conventional illustration of a Belt type HPHT imperativeness. ( International Diamond Lab ) BARS system is developed at the Russian Academy of Sciences in Novosibirsk. It is really similar to the belt type system. It is made up by eight outer anvils with a spherical outer form to which force per unit area is applied and six inner anvils to multiply the force per unit area to the sample. BARS system is the most compact, efficient, and economical of all the diamond-producing imperativenesss. ( International Diamond Lab )Hot-filament CVDHot-filament CVD is besides called thermally activated CVD. It is one of the earliest developed attacks to low force per unit area synthesis of diamond. A furnace lining metal, normally tungsten, is used as a fibril, is heated to high temperature around 2300 & A ; deg ; C. The temperature can be reach by opposition warming and the high temperature aid to trip the hydrocarbon-hydrogen gas mixture. The fibril is located a few millimetres above the substrate besides provides warming for the substrate. The hydrocarbon-hydrogen gas mixture is allowe d to flux across the hot fibril, where it is activated. Hot-filament CVD reactors are cheap and easy to build. The filament temperature, the place of the substrate with regard to the fibril, and the gas flow kineticss play of import factors in the procedure. However, there are several disadvantages of this technique such as taint of the diamond movie by the fibril, eroding and sagging of the fibril, and a comparatively slow growing rate. It is besides necessary to provide changeless power throughout a deposition utilizing a proper power accountant but the uniformity of the substrate temperature is hard to keep when utilizing multiple fibrils. ( Reinhard ) Figure 6 Conventional diagram of the hot fibril CVD procedure demoing the basic elements.Microwave plasma-enhanced CVD ( MPECVD )Microwave plasma enhanced CVD is widely used for diamond deposition. A magnetron is normally used to bring forth micro-cook energy at 2.45 GHz and a wave-guide assembly is used to match the energy to a resonating pit. MPECVD is an electrodless procedure, which is an advantage over other techniques, and there is no taint from the electrode stuff. The microwave plasma excitement of H generates superequilibrium concentrations of atomic H. The hits of negatrons with gas atoms and molecules generate high ionisation fractions. ( Reinhard ) Figure 7 Conventional apparatus of the CVD synthesis of diamond. ( Markus )Direct current ( DC ) arcjet discharge techniqueDC arcjet discharge is a really high growing rate procedure. Normally, this technique will be usage to synthesis midst and freestanding diamond substrates. A DC arcjet discharge reactor for diamond deposition consists of a gas injection nose, composed of a rod cathode, which is normally made of wolframs, concentric with a tubing anode. Gass are allowed to flux between the cathode and anode. Gass will be spray out from an opening in the anode so a high temperature discharge jet is created and sustained by a DC electromotive force across the electrode. The substrate is located downstream from the jet watercourse on a water-cooled substrate phase. Carbon precursor and graphite etchant gases would be introduced at different locations depending on the coveted activation temperature. Although this technique is frequently used because of the high growing rate, there is several disadvantages of it such as the movie can undergo from high compressive emphasiss, microvoids, and high surface raggedness. ( Reinhard )CombustionCombustion is good cognize for its scalable nature, minimum public-service corporation demands, and significantly cut down capital costs relative to plasma assisted procedures. The most of import parametric quantity in burning synthesis is the oxygen-to-acetylene ratio, defined as R = O2: C2H. At values of R near 1.0, a impersonal fire is achieved, which is defined as the status where the feather part merely disappears because all the ethyne is consumed in the primary fire. The diamond growing regimes as a map of composing are showed in Figure 9. The highest quality diamond is obtained in somewhat rich fires, when oxygen-to-acetylene ratio is about 0.85-1.0. The value of R at which a impersonal fire occurs is dependent on both burner design and entire flow rate. Substrate temperature is control in a scope from 950-1650K during burning CVD. With high temperatures, substrates has been limited to stuffs such as Si, aluminum oxide, and diamond. However, it is non easy to mensurate the substrate temperature in burning CVD due to the utmost heat fluxes present. Substrate temperature controls growing rate and morphology. As the substrate temperature additions, the growing rate is relative. ( See Figure 9 ) However, after the growing rate reaches its upper limit, an look of a rapi d diminution in both the quality and the growing rate is observed. ( Reinhard ) Figure 8 Two designs of atmospheric level fire burners: ( a ) a coflow design and ( B ) a cornet bell design ( Reinhard ) Figure 9 The consequence of substrate temperature on growing rate observed in burning CVD of diamond. In atmospheric torches the maximal growing rate occurs at substrate temperatures between 1450 and 1650 K ( Reinhard )MetastableDiamond is uncommon because of two grounds. First, the dynamicss of graphite formation are much faster than the dynamicss of diamond formation in normal status. Second, a big activation energy barrier between black lead and diamond prevents thermic activation of diamond into black lead. ( See Figure 10 ) When diamond is synthesized under conditions where black lead is the stable stage of C, the consequence of synthesising diamond is normally failed. It is because the denseness of diamond is greater than the denseness of black lead. ( Anthony ) At ordinary temperatures and force per unit areas, although diamond is non the minimal energy province of C, it is besides non an unstable phase of C. ( see Figure 1 ) Therefore, if C atoms are in the diamond lattice spacial agreement, the solid does non spontaneously change over to graphite under low temperature, low force per unit area conditions. Formation of diamond from nascent C incorporating species under metastable conditions is both thermodynamically allowed and readily achieved under proper deposition conditions. It is the lower temperatures and force per unit areas associated with this method of diamond synthesis that have offered the capableness of direct deposition of diamond on a assortment of substrates and have opened the possibility of new applications of diamond. For many such applications, the diamond thickness demand be merely on the order of microns ; hence the constructions are referred to as diamond movies. ( Reinhard ) Figure 10 Energy diagram of C ( Anthony )StructurePure diamond is composed merely by C and arranged in the diamond lattice. ( See Figure 11 In theory, pure diamonds are crystalline and colorless. ) In diamond lattice, each C atom has four nearest neighbours in the tetrahedral agreement associated with sp3 chemical bonds. The nearest neighbour distance is 1.54 & A ; Aring ; and the unit cell dimension is 3.567 & A ; Aring ; . The denseness of diamond is 3.515g/cm3. The measure of diamond is normally referred to carats, where one carat is equal to 200mg. ( Reinhard ) However, quality of diamond is considerable because both natural and man-made diamond may incorporate drosss and defects. Diamonds occur in assorted colour and these are caused by defects, including replaced drosss and structural defect. These defects will impact the light soaking up. Therefore, diamonds are characterized into type I, type II and some subtypes, with the former containing N as an dross and the latter being basically nitrogen free. ( John, Polwart and Troupe ) ( a ) ( B ) Figure 11 a ) Conventional diagram of carbon-carbon bonding in diamond and black lead ( Anthony ) B ) 3D diamond latticeType IType I diamonds in which impurity-related optical and paramagnetic soaking up are dominated by N defects. Normally, type I diamonds are crystalline to 300 nanometers. ( Robertson R. ) In general, the dross content of natural type I diamonds is more varied compared to that of type II diamonds. The most apparent difference between type I and II diamonds comes from IR soaking up spectra, which are considered to be the chief standard for this distinction. ( See Figure 12 for Refraction index of type I and type II ) About 98 % of natural diamonds contain nitrogen with concentrations noticeable in optical soaking up. 74 % of them have a N content high plenty to be decidedly classified as type I. Nitrogen is regularly nowadays in natural diamonds at degrees every bit high as 200 to 4000 ppm. ( Zaitsev ) In type I, there are three subtypes, type Ia, type Ib, and type Ic. Type Ia contains N in farily significant sums of the order of o.1 % which most natural diamonds belong to this type. Type Ib besides contains N but in spread substitutional signifier which most of man-made diamonds are this type. ( Markus ) Type Ic include diamonds that contain high concentration of disruptions. Even type Ic does n't truly related to contaimination of N but the feature of type Ic is categorized in type I. Type Ic has the absoption continuum at wavelength below 900nm and a extremum at 560nm. ( Zaitsev ) Figure 12 Refraction index of type IIa and type I natural diamonds in the UV spectral part ( Zaitsev )Type IIType II includes diamonds demoing no optical and paramagnetic soaking up due to nitrogen-related defects. The measure of N found in type II is really small. ( Below 1017cm-3 ) Type II diamonds are exhibited optical transparence up to 230 nanometers ( Robertson R. ) . However, it is rare to happen natural diamonds without nitrogen-related defects in soaking up. Merely 1 to 2 % of type II diamonds are found in nature. ( Zaitsev ) There are two subtypes are in type II, type IIa and type IIb. Type IIa is non effectual by N and this type of diamonds has enhanced optical and thermic belongingss. However, they are rare to happen in natural. Type IIb is a really pure type which has semiconducting belongingss and this type of diamond is normally find in bluish and highly rare in nature. ( Markus )Influence of defects and drossNitrogen does non strongly act upon the refractile index of diamond in the seeable spectral part. Therefore the refractile index for types I and II natural diamonds may non differ by more than 1 % . ( Robertson R. ) Since there is no definite inclination for discriminatory double refraction of diamonds of any type, it indicated that nitrogen dross does non straight act upon the double refraction of diamond. However there is a tendency such that natural diamonds of mean size, with an enhanced double refraction, are ultraviolet conveying. Diamonds with a low double refraction are normally ultraviolet-opaque and N is the caused for this consequence. Diamond with low N, type II, have a really distorted stressed crystal lattice. ( Zaitsev ) The double refraction of diamond is caused by fictile distortion, elastic distortion near inclusion, growing striations, growing sector boundaries, disruptions, grain boundaries, and diamond-substrate boundaries. The phenomena occur in both types of diamonds. The highest double refraction is found in fragments of natural diamonds where dodecahedral diamonds shows the least double refraction. Defects arises from sheets of stacking mistakes are expected to ensuing the double refraction contrast weaker than from partial disruptions. However, partial disruptions or stacking fault sheets will be seen merely the background double refraction is really low. ( Zaitsev )PropertiesDiamonds have some great belongingss that other stuff still can non be compared and that is the ground why people would wish to understand how diamond is formed and synthesis diamond to cut down the cost of the stuff. Diamond is good known for high thermic conduction, high electrical electric resistance, low coefficie nt of clash, high grade of chemical inertness, high optical scattering, big energy spread, low infrared soaking up, and high dislocation electromotive force. See Table 1 for outstanding belongingss of diamond. Table 1 Some belongingss of diamond ( Markus )Thermal PropertiesAs mentioned, diamond has high thermic conduction. For high quality individual crystals, normally type IIa, the thermic conduction, ? , is about 22W/cm & A ; deg ; C at room temperature. This belongings is due to the stiffness of diamond bond and the diamond construction, which rise to a high acoustic speed and a really high characteristic temperature. Recently, research worker has reported the best thermic conduction of the movie is about 11W/cm & A ; deg ; C. For midst movie, the conduction is about17W/cm & A ; deg ; C at room temperature. ( J.E. Graebner ) Figure 13 indicates the relation between thermic conduction and movie thickness, where thermic conduction additions with movie thickness. Thermal conducitivy besides depends on grain boundary. Diamond ‘s thermic conduction additions with decreasing temperature, making a upper limit of 42 W/cm-K near 80 K, after making the upper limit the thermic conduction les senings. Impurities, such as N, cut down the thermic conduction. Type I diamonds with 0.1 % N merely have 50 % thermic conduction values of type II diamonds in room temperature. Isotropic pureness increases the thermic conduction. Man-made diamond crystals grows with pure carbon-12 have thermic conductions 50 % higher than those of natural diamond for which the atomic weight is 12.01 because the stuff contains 1.1 % carbon-13. ( Zaitsev ) Figure 13Measured thermic conduction at 25 & A ; deg ; C for five samples ( squares ) . Solid circles show the derived conduction. The horizontal dotted line indicates the typical conduction reported for individual crystal high quality ( Type IIa ) diamond. ( J.E. Graebner )Optical PropertiesDiamond movies are normally crystalline in the infrared, with the exclusion of the carbon-hydrogen absorbing sets centered at about 2900cm-1, weak absorbing in the seeable spectrum, and increasing absorbing with diminishing wavelength in the UV visible radiation. The optical spread value is range from 0.38 to 2.72 for diamond movies. ( A. ) The index of refraction, both the existent portion N and fanciful portion K, and its spectroscopic fluctuation has been found to be dependent on the readying conditions and H content of the movies. Its value at 632.8 nanometers can be adjusted from 1.7 to 2.4 by seting the deposition conditions. ( A. ) This refractile index is big comparison to other crystalline stuff. With big refractile index, it is besides found big contemplation coefficient and a little angle for entire internal contemplation. ( Zaitsev ) The index of refraction is besides affected by the H content in the diamond movies and by and large additions with diminishing concentration of edge H. It is, nevertheless, dependant on the concentration of edge H and non entire H content in the movie. A higher index of refraction normally indicates diamond with stronger crosslinking, higher hardness, and better wear opposition. ( A. ) Diamond is besides photoconductive. There is a strong photoconductive extremum at 225 nanometers due to excitement of negatrons across the set spread in pure diamond, and in B doped diamond there are besides peaks from 1.4 to 3.5 ?m due to excitement of the deep-lying acceptor degrees. ( Reinhard )Electrical belongingssThe electrical belongings of diamond movie is good known for big set spread. Diamond have a modest bandgap. The energy set construction of diamond exhibits an indirect energy spread with a value of 5.47 electron volt at 300 K. This is sufficiently big that at near room temperature the intrinsic bearer concentration is negligible and the stuff is an dielectric with a dielectric invariable of about 5.7. ( Zaitsev ) ( See Figure 14 for set construction ) In an dielectric the valency negatrons form strong bonds between neighbouring atoms and accordingly these bonds are hard to interrupt. Thus, the bandgap is big and there are no free negatrons to take part in current condu ctivity at or near room temperature. ( Markus ) Figure 14 Activation energies for some drosss in diamond. B is boron for P type, P is phosphorus for n-type, and N is nitrogen. ( Markus ) The set construction of diamond movie is assumed to dwell merely a mobility spread, where bearers shacking in spread provinces are localized. The mobility spread produces semiconducting material behaviour, nevertheless, the high denseness of localised spread provinces leads to low apparent bearer mobilities and significantly degrades the semiconducting belongingss of stuff. Diamond movies normally have high electrical electric resistances from 102-1016? , depending on the deposition status ( A. ) The electrical conduction of diamond is more sensitive to drosss than the thermic conduction. The electrical electric resistance can be reduced by several orders of magnitude through incorporation of metals or N in the movies. The lessening of electric resistance by incorporation of dopants possibly related to a dopant induced graphitization. However, more groundss are needed to turn out. Boron doped p-type diamond exists in nature. The growing of B doped diamond movies by CVD techniques has been achieved by adding B incorporating molecules to the gas mixture in either a microwave or in a hot fibril reactor ensuing in the growing of B incorporating p-type diamond movies. ( A. ) ( R. ) N-type doping is much more complicated. It is still questionable about the possible giver atom that will give a shallow plenty energy degree in the spread to be sufficiently ionized at room temperature. Most late clear giver activity is phosphorus doped for n-type diamond. In Figure 15, the dependance of the electric resistance on measurement temperature. Similar inclines are obtained for all samples proves that in this temperature run the conductivity mechanism is thermally activated, with an activation energy of 0.46 electron volt, instead independent of growing conditions. ( R. ) Figure 15 Temperature dependance of the electric resistance of n-type diamond, doped with different sums ( ppm ) of P ( 300,800 K ) . ( R. )B. Mechanical PropertiesDiamond is the hardest known substance. Diamond besides has the lowest squeezability, the highest elastic modulus, and the highest isotropous velocity of sound ( 18,000 m/sec ) of any known materia ( Nazare and Neves ) . The grade of hardness is quantified in footings of both opposition to indenture and scratch ( or abrasion ) opposition. In footings of squeezability, the ratio of tensile emphasis to linear strain, or Young ‘s modulus, is 1050 GPa, a value about five times higher than that of steel. However under different methods of proving, the Young ‘s modulus is different and C11, C12, C44. Table 2 provides the Young ‘s moduli of diamond with different trial methods. Because of its brickle nature, diamond is non peculiarly strong. ( Markus ) Table 2 Elastic moduli of diamond ( GPa ) ( Nazare and Neves ) Method C11 C12 C44 Ultrasonics 950 390 430 X raies 1100 330 440 Brillouin 949 151 521 The mechanical strength of diamond is influenced by a figure of important factors, including the applied emphasis system, the ambient temperature and the grade of both internal ( drosss ) and external ( surface coating ) flawlessness. Fracture occurs when a certain degree of emphasis is applied and the manner of failure will be that which requires the smallest emphasis. Materials, where the bonding is preponderantly covalent or where there is a significant grade of covalent bonding, have a big built-in lattice opposition to dislocation gesture and failure occurs at low emphasiss, below the theoretical break emphasis. Diamond, as with any other crystalline stuff, can neglect by either brickle break, cleavage, or in a ductile manner, flow by a shear procedure. Although thermic belongingss and electrical conduction are both extremely affected by N, there is no clear grounds found that mechanical belongingss are clear related to N. ( Nazare and Neves )Highly inert chemicallyDiamond is ex tremely inert chemically, except for two state of affairss. It is susceptible to oxidising agents at high temperatures. For illustration, if diamond is heated in the presence of O, oxidization Begins at around 900 K. Besides, diamond is capable to chemical onslaught by certain metals at high temperatures. These include carbide formers such as wolframs, Ta, Ti, and Zr every bit good as dissolvers for C such as Fe, Co, manganese, nickel, Cr, and Pt. ( Zaitsev )ApplicationsDiamond is a really utile stuff because of the outstanding belongingss including high thermic conduction, high electrical electric resistance, low coefficient of clash, high grade of chemical inertness, high optical scattering, big energy spread, low infrared soaking up, and high dislocation electromotive force. With these belongingss, diamond is used for diverse application besides jewellery. They are normally used in mechanical application, optical applications, thermic applications, and sensor applications. Diamon d can be used for scratchy and wear opposition coating for cutting tools, lenses, Windowss for power optical masers, diffractive optical elements, heat sinks for power transistors, semiconducting material optical maser arrays, solar blind photodetector, and radiation hard and chemically inert sensors. Table 3 Future application countries for diamond electronics. ( Markus )Film editing ToolsSingle crystal diamond is used for coating of modulated or layered composing of two or more passage metal compounds. It is common to utilize diamond coating for certain types of crunching wheels or cutting of extremely scratchy metals and metals. There are two ways to use diamond on to the film editing tools. First, turning comparatively thick beds of CVD diamond from which separate freestanding pieces are obtained. These pieces are so brazed onto a cutting tool. Second, straight deposited diamond onto the film editing tools. ( Markus ) Often, high-quality diamonds are selected for usage in dressing tools for non-ferrous metals, aluminium, brass bronze, ceramics, black lead, and glass fiber-reinforced construction. ( Markus ) ( Hammond and Evans ) Single-point diamond is mounted in a metal matrix. They are normally used to dress and leave or reconstruct the needed geometric form to certain scrat chy wheels. Two typically signifiers of such film editing tools are single-point and multi-point. Today, individual or multi-point cutters include milling, turning, drilling, cutting-off and slitting. ( Hammond and Evans )Demonstrated surfacing diamond onto hardmetalsHardmetals are the most valuable and of import substrates for coated tools, due to their intrinsic belongingss and their broad scope of mechanical belongingss. They consist of WC and Co with add-ons of TiC, ( Ta5Nb ) C, and VC, which chiefly change their hardness and wear opposition. The sum of Co binder is mostly responsible for ductileness or crispness. Hardmetals have been used as wear parts and film editing tools for decennaries, with and without surfacing applications. Normally, successful diamond coatings on WC-Co substrates have no or a really low sum of three-dimensional carbides ( TiC ) and besides a comparatively low Co content. Both Co and TiC add-ons increase the thermic enlargement coefficient of the hardmetal and cut down the adhesion of the diamond coating. A high Co vapour force per unit area and its high mobility on the substrate surface influence diamond deposition. In the gas stage environing the substrate surface, Co catalyses the formation of nondiamond C stages, which can be deposited at the interface prior to the diamond formation. How and why the Co drops reach the diamond coating surface is non yet to the full understood. Surface forces might play an of import function ( See Figure 16 ) . Figure 16 Co as portion of the hardmetal binder stage and its influences on the diamond depositionElectrochemical ApplicationsElectrochemical behaviour of boron-doped CVD diamond is one of the most promising applications of conductive diamond. Boron doped diamond fits the demand for an electrode operates inertly and without impairment in rough chemical environments. Compare to platinum electrodes, diamond electrodes provide a much wider potency scope over which no important H2O decomposition occurs. ( Reinhard ) Diamond electrodes are suited substrates for reactions crossing a broad possible scope in aqueous solutions. They besides have the advantage of chemical stableness, even in extremely aggressive environments. In Figure 17 the I-V curves obtained with a B doped CVD diamond electrodes in assorted ( KI, KBr, and HCl ) solutions are shown. The behaviour of the doped diamond electrode is much superior to that of the commonly used baronial metal electrodes. Diamond bears as a stuff for the fiction of cold cathode or other negatron breathing devices requires the diamond to be electrically conductive, with no demand for an accurately known doping degree. ( R. ) Figure 17 Current V. Potential of a extremely B doped CVD diamond electrode in ( a ) 1 M KI ; ( B ) 1 M KBr and ( degree Celsius ) 1 M HCl. Scan rate 150 mV/s. The alone negatron emanation belongingss of diamond are the most promising applications of semiconducting diamond. Although, no clear apprehension of the natural philosophies that determined the negatron emanation from diamond emerges. There are still many applications such as field emanation from diamond surfaces utilizing diamond to conductive.Thermal ManagementThe high thermic conduction of diamond, combined in some instances with its chemical inertness and high electrical electric resistance, makes it of involvement for a assortment of thermic direction applications. Laser diamond heat sinks and other thermic direction substrates formed from CVD polycrystalline diamond are illustrations of available merchandises. Because diamond combines exceptionally high thermic conduction with exceptionally low electrical conduction, it is of considerable involvement in electrical packaging applications. It provides efficient waies for heat flow without compromising the electrical isolation of single constituents. ( Reinhard )Transmission ApplicationsDiamond provides a window with high transmission for assorted parts of the electromagnetic spectrum. It is an ideal radiation window stuff in peculiar for applications affecting high power degrees and mechanical, thermic or chemical burden. Due to its big bandgap ( 5.5 electron volt ) and the deficiency of infrared active cardinal vibrational manners, diamond is optically crystalline over a big wavelength scope. Even at elevated temperatures, diamond remains crystalline, since the big bandgap does non let the formation of free bearers. In the x-ray part of the spectrum, diamond is of involvement for x-ray lithography masks. The low atomic figure of diamond consequences in low x-ray soaking up. Another illustration is in high-octane gyrotrons such as are used in merger research. This application requires the transmittal of really big powers ( megawatts ) at microwave frequences ( 170 GHz ) every bit good as the ability to dis perse heat quickly. The ability to convey high powers in the optical part of the spectrum is of involvement to laser interior decorators because the design of high-power optical masers is power limited by harm bounds to laser optics instead than restrictions of the optical maser medium or pumping mechanisms. The abrasion opposition and chemical inertness make diamond of involvement as an optical coating stuff every bit good. ( Reinhard ) Diamond is known for its broadband optical transparence covering the UV, seeable, close and far IR. In this scope the optical transmittal exhibits merely minor intrinsic soaking up sets originating from two- phonon ( 1332-2664 cm-1 ) and three-phonon ( 2665-3994 cm-1 ) passages. The maximal soaking up coefficient sums to 14 cm-1 at 2158 cm-1. This holds true for optical class CVD-diamond as shown in Figure 18. The soaking up around 10 ^m is of peculiar involvement for CO2-laser constituents and because many IR detectors operate within the 8-12 ?m atmospheric window. ( Nazare and Neves ) Figure 18Transmission spectrum of a high-quality CVD-diamond window ( thickness: 150 ?m ) ( Nazare and Neves ) CVD-diamond is besides used as vacuity Windowss for high-power microwave ( Gyrotron ) tubing. These Gyrotron tubings are used for the negatron cyclotron warming of merger plasmas. Power degrees transcending 1 MW at frequences of around 100 GHz have been demonstrated. Until late the end product window of these devices has been the most critical constituent restricting the maximal end product power or the pulse continuance. In this context CVD-diamond window with H2O edgecooling is found to be really promising. The highly high power degree requires really low insulator losingss. CVD-diamond exhibits loss tangent values every bit low as 10-5 ( at 140 GHz ) . Below 350-400 & A ; deg ; C there is practically no temperature dependance. In the 10- 145 GHz range the loss tangent decreases with frequence as 1/f [ 27 ] or as 1/f05. ( Nazare and Neves )X-ray lithography masksThe declaration bound of optical lithography is defined by diffraction and sprinkling as the characteristic size approach es the exposing wavelength. X ray lithography, which uses significantly shorter radiation ( 0.8-1.5 nm versus 300-400 nanometer ) , offers a proficient way to accomplishing the higher declaration. However, several factors have delayed the execution of X-ray lithography on the production line for IC fiction. The major non-technical factor is related to the immense constitutional optical technological substructure which has continued to do important betterments by utilizing measure and repetition exposure tools, integrating multilevel resist, using contrast foils, utilizing shorter wavelength radiation, planing higher numerical aperture optics, which has efficaciously delayed the execution of X-ray lithography. The proficient barriers to X-ray lithography execution include the absence of a dependable, high volume, low defect denseness X-ray mask engineering, a high velocity X-ray resist, a high velocity, low cost exposure/alignment tool. The best mask stuff has low atomic figure since the X-ray transparence improves with diminishing atomic figure. TABLE 1 reveals the failing of polymers as membrane stuff campaigners. They are non merely hygroscopic but are automatically soft and hence easy distorted. The metals Ti and Be are reasonably stiff ; nevertheless, their opacity is troublesome, but non pathological, since alliance Windowss can be etched in the membrane after overcoating with polyimide to back up the alliance form. Beryllium would be first-class were it crystalline, dismissing its toxicity. Si and its nitride and oxide are good from an X-ray and optical transparence point of view but lack the mechanical stiffness of the furnace linings like SiC, BN and diamond. Si has the important advantage of a big installed engineering base and capital equipment handiness. As can be seen, diamond has the highest stiffness factor S of any stuff. There are other factors to see in choosing a stuff such as: scale-up of fiction procedure, X-ray-induced debasement, surface smoothness, two-dimensionality, secondary negatron emanation induced by the X raies, adhesion of metallization. Diamond ‘s low mass soaking up coefficient and low denseness make it compatible with a assortment of X-ray beginnings. ( Nazare and Neves ) Table 4 Comparison of stuffs based on X-ray transparence Texas, optical transparence to, and mechanical stiffness S. ( Nazare and Neves ) Material Texas ( ?m ) t0 S = Et0Z ( I-V ) ( GPa Polyimide 8.7 & A ; gt ; 5 43 Mylar 8.5 & A ; gt ; 5 42 Titanium 1.09 Opaque–Be 42.0 Opaque–Silicon 9.6 2 362 Al2O3 0.8 1 448 SiO2 4.99 5 444 Si3N4 7.71 6 728 BN 7.94 4 420 SiC 6.81 3 1590 Diamond 5.9 2 2336Detectors and DetectorsDiamond-based devices are besides of involvement for observing a assortment of radiation types every bit good as feeling assorted physical parametric quantities such as temperature and force per unit area. For illustration, diamond thermal resistors have been proposed for temperature measuring in hostile environments such as chemical processing, gearbox oil, and cryogenies. The piezoresistive consequence of diamond has been used to feel force per unit area, and p-type CVD polycrystalline diamond is reported to hold a big piezoresistive gage factor [ 12 ] . Diamond is highly radiation hard, with a 55-eV supplanting energy for a C atom in the diamond lattice. It besides acts as an ionizing radiation sensor and is hence of involvement for radiation measurings where exposure to big doses is required. The big set spread of diamond make it of involvement as a UV sensor, based on photoconduction, which is blind to seeable visible radiation. ( Reinhard )Decision