Gas is one of the four fundamental states of matter. A pure gas may be made up of individual atoms, elemental molecules made from one type of atom, or compound molecules made from a variety of atoms. A gas mixture would contain a variety of pure gases much like the air. What distinguishes a gas from liquids and solids is the vast separation of the individual gas particles; this separation makes a colorless gas invisible to the human observer. The interaction of gas particles in the presence of electric and gravitational fields are considered negligible, as indicated by the constant velocity vectors in the image; the gaseous state of matter is found between the liquid and plasma states, the latter of which provides the upper temperature boundary for gases. Bounding the lower end of the temperature scale lie degenerative quantum gases which are gaining increasing attention. High-density atomic gases super cooled to low temperatures are classified by their statistical behavior as either a Bose gas or a Fermi gas.
For a comprehensive listing of these exotic states of matter see list of states of matter. The only chemical elements that are stable diatomic homonuclear molecules at STP are hydrogen, nitrogen and two halogens: fluorine and chlorine; when grouped together with the monatomic noble gases – helium, argon, krypton and radon – these gases are called "elemental gases". The word gas was first used by the early 17th-century Flemish chemist Jan Baptist van Helmont, he identified the first known gas other than air. Van Helmont's word appears to have been a phonetic transcription of the Ancient Greek word χάος Chaos – the g in Dutch being pronounced like ch in "loch" – in which case Van Helmont was following the established alchemical usage first attested in the works of Paracelsus. According to Paracelsus's terminology, chaos meant something like "ultra-rarefied water". An alternative story is that Van Helmont's word is corrupted from gahst, signifying a ghost or spirit; this was because certain gases suggested a supernatural origin, such as from their ability to cause death, extinguish flames, to occur in "mines, bottom of wells and other lonely places".
In contrast, French-American historian Jacques Barzun speculated that Van Helmont had borrowed the word from the German Gäscht, meaning the froth resulting from fermentation. Because most gases are difficult to observe directly, they are described through the use of four physical properties or macroscopic characteristics: pressure, number of particles and temperature; these four characteristics were observed by scientists such as Robert Boyle, Jacques Charles, John Dalton, Joseph Gay-Lussac and Amedeo Avogadro for a variety of gases in various settings. Their detailed studies led to a mathematical relationship among these properties expressed by the ideal gas law. Gas particles are separated from one another, have weaker intermolecular bonds than liquids or solids; these intermolecular forces result from electrostatic interactions between gas particles. Like-charged areas of different gas particles repel, while oppositely charged regions of different gas particles attract one another. Gaseous compounds with polar covalent bonds contain permanent charge imbalances and so experience strong intermolecular forces, although the molecule while the compound's net charge remains neutral.
Transient, randomly induced charges exist across non-polar covalent bonds of molecules and electrostatic interactions caused by them are referred to as Van der Waals forces. The interaction of these intermolecular forces varies within a substance which determines many of the physical properties unique to each gas. A comparison of boiling points for compounds formed by ionic and covalent bonds leads us to this conclusion; the drifting smoke particles in the image provides some insight into low-pressure gas behavior. Compared to the other states of matter, gases have low viscosity. Pressure and temperature influence the particles within a certain volume; this variation in particle separation and speed is referred to as compressibility. This particle separation and size influences optical properties of gases as can be found in the following list of refractive indices. Gas particles spread apart or diffuse in order to homogeneously distribute themselves throughout any container; when observing a gas, it is typical to specify a frame of length scale.
A larger length scale corresponds to a global point of view of the gas. This region must be sufficient in size to contain a large sampling of gas particles; the resulting statistical analysis of this sample size produces the "average" behavior of all the gas particles within the region. In contrast, a smaller length scale corresponds to a particle point of view. Macroscopically, the gas characteristics measured are either in terms of the gas particles themselves or their surroundings. For example, Robert Boyle studied pneumatic chemistry for a small portion of his career. One of his experiments related the macroscopic properties of volume of a gas, his experiment used a J-tube manometer which looks like a test tube in the shape of the letter J. Boyle trapped an inert gas in the closed end of the test tube with a column of mercury, thereby ma
Encyclopædia Britannica, Eleventh Edition
The Encyclopædia Britannica, Eleventh Edition is a 29-volume reference work, an edition of the Encyclopædia Britannica. It was developed during the encyclopaedia's transition from a British to an American publication; some of its articles were written by the best-known scholars of the time. This edition of the encyclopedia, containing 40,000 entries, is now in the public domain, many of its articles have been used as a basis for articles in Wikipedia. However, the outdated nature of some of its content makes its use as a source for modern scholarship problematic; some articles have special value and interest to modern scholars as cultural artifacts of the 19th and early 20th centuries. The 1911 eleventh edition was assembled with the management of American publisher Horace Everett Hooper. Hugh Chisholm, who had edited the previous edition, was appointed editor in chief, with Walter Alison Phillips as his principal assistant editor. Hooper bought the rights to the 25-volume 9th edition and persuaded the British newspaper The Times to issue its reprint, with eleven additional volumes as the tenth edition, published in 1902.
Hooper's association with The Times ceased in 1909, he negotiated with the Cambridge University Press to publish the 29-volume eleventh edition. Though it is perceived as a quintessentially British work, the eleventh edition had substantial American influences, not only in the increased amount of American and Canadian content, but in the efforts made to make it more popular. American marketing methods assisted sales; some 14% of the contributors were from North America, a New York office was established to coordinate their work. The initials of the encyclopedia's contributors appear at the end of selected articles or at the end of a section in the case of longer articles, such as that on China, a key is given in each volume to these initials; some articles were written by the best-known scholars of the time, such as Edmund Gosse, J. B. Bury, Algernon Charles Swinburne, John Muir, Peter Kropotkin, T. H. Huxley, James Hopwood Jeans and William Michael Rossetti. Among the lesser-known contributors were some who would become distinguished, such as Ernest Rutherford and Bertrand Russell.
Many articles were carried over from some with minimal updating. Some of the book-length articles were divided into smaller parts for easier reference, yet others much abridged; the best-known authors contributed only a single article or part of an article. Most of the work was done by British Museum scholars and other scholars; the 1911 edition was the first edition of the encyclopædia to include more than just a handful of female contributors, with 34 women contributing articles to the edition. The eleventh edition introduced a number of changes of the format of the Britannica, it was the first to be published complete, instead of the previous method of volumes being released as they were ready. The print type was subject to continual updating until publication, it was the first edition of Britannica to be issued with a comprehensive index volume in, added a categorical index, where like topics were listed. It was the first not to include long treatise-length articles. Though the overall length of the work was about the same as that of its predecessor, the number of articles had increased from 17,000 to 40,000.
It was the first edition of Britannica to include biographies of living people. Sixteen maps of the famous 9th edition of Stielers Handatlas were translated to English, converted to Imperial units, printed in Gotha, Germany by Justus Perthes and became part this edition. Editions only included Perthes' great maps as low quality reproductions. According to Coleman and Simmons, the content of the encyclopedia was distributed as follows: Hooper sold the rights to Sears Roebuck of Chicago in 1920, completing the Britannica's transition to becoming a American publication. In 1922, an additional three volumes, were published, covering the events of the intervening years, including World War I. These, together with a reprint of the eleventh edition, formed the twelfth edition of the work. A similar thirteenth edition, consisting of three volumes plus a reprint of the twelfth edition, was published in 1926, so the twelfth and thirteenth editions were related to the eleventh edition and shared much of the same content.
However, it became apparent that a more thorough update of the work was required. The fourteenth edition, published in 1929, was revised, with much text eliminated or abridged to make room for new topics; the eleventh edition was the basis of every version of the Encyclopædia Britannica until the new fifteenth edition was published in 1974, using modern information presentation. The eleventh edition's articles are still of value and interest to modern readers and scholars as a cultural artifact: the British Empire was at its maximum, imperialism was unchallenged, much of the world was still ruled by monarchs, the tragedy of the modern world wars was still in the future, they are an invaluable resource for topics omitted from modern encyclopedias for biography and the history of science and technology. As a literary text, the encyclopedia has value as an example of early 20th-century prose. For example, it employs literary devices, such as pathetic fallacy, which are not as common in modern reference texts.
In 1917, using the pseudonym of S. S. Van Dine, the US art critic and author Willard Huntington Wright published Misinforming a Nation, a 200+
Rakhine State is a state in Myanmar. Situated on the western coast, it is bordered by Chin State to the north, Magway Region, Bago Region and Ayeyarwady Region to the east, the Bay of Bengal to the west, the Chittagong Division of Bangladesh to the northwest, it is located between latitudes 17°30' north and 21°30' north and longitudes 92°10' east and 94°50' east. The Arakan Mountains, rising to 3,063 metres at Victoria Peak, separate Rakhine State from central Burma. Off the coast of Rakhine State there are some large islands such as Cheduba and Myingun Island. Rakhine State has an area of 36,762 square kilometres and its capital is Sittwe; the term Rakhine is believed to have been derived from the Pali word Rakkhapura, meaning "Land of Ogres" a pejorative referring to the original Negrito Australoid inhabitants. The Pali word "Rakkhapura" means "land of the people of Rakhasa", they were given this name in honour of their preservation of their national heritage and ethics or morality. The word Rakhine means, "one who maintains his own race".
In the Rakhine language, the land is called Rakhinepray, the ethnic Rakhine are called Rakhinetha. The term, was introduced when the Arakan Kingdom was established and has been continued to use until the recent time and is still popularly used in English. Many English language users eschew; the history of the region of Arakan State can be divided into seven parts. The first four divisions and the periods are based on the location of the centre of power of the main independent Rakhine-dominated polities in the northern Rakhine region along the Kaladan River. Thus, the history is divided into the Dhanyawadi, Waithali and Mrauk U. Mrauk U was conquered by the Konbaung dynasty of Burma in 1784–85, after which Rakhine became part of the Konbaung kingdom of Burma. In 1824, the first Anglo-Burmese war erupted and in 1826, Rakhine was ceded to the British as reparation by the Burmese to the British. Rakhine thus became part of the province of Burma of British India. In 1948, Burma was given independence and Rakhine became part of the new federal republic.
Based on Rakhine oral histories and inscriptions in certain temples, the history of the Rakhine region dates back nearly five thousand years. The Rakhine people trace their societal history back to as far as 3325 BCE and have given a lineal succession of 227 native monarchs and princes down to the last ruler in 1784, they describe their territory as including, in varying points of time, the regions of Ava, the Irrawaddy Delta, the port town of Thanlyin and parts of eastern Bengal. However, the expanse of the successive Rakhine kingdoms does not corroborate with certain known historical documentation. According to Rakhine legend, the first recorded kingdom, centred around the northern town of Dhanyawadi, arose in the 34th century BCE and lasted until 327 CE. Rakhine documents and inscriptions state that the famed Mahamuni Buddha image was cast in Dhanyawady in around 554 BCE when the Buddha visited the kingdom. After the fall of Dhanyawadi in the 4th century CE, the centre of power shifted to a new dynasty based in the town of Waithali.
The Waithali kingdom ruled the regions of Rakhine from the middle of the 4th century to 818 CE. The period is seen as the classical period of Rakhine culture and Buddhism, as the Waithali period left behind more archaeological remains than its predecessor. A new dynasty emerged in four towns along the Laymro river as Waithali waned in influence, ushered in the Lemro period, where four principal towns served as successive capitals; the final Kingdom of Mrauk U was founded in 1429 by Min Saw Mon. It is seen by the Rakhine people as the golden age of their history, as Mrauk U served as a commercially important port and base of power in the Bay of Bengal region and involved in extensive maritime trade with Arabia and Europe; the country declined from the 17th century onwards after the loss of Chittagong to the Mughal Empire in 1666. Internal instability and dethroning of kings were common; the Portuguese, during the era of their greatness in Asia, gained a temporary establishment in Arakans. On 2 January 1785, the internally divided kingdom fell to invading forces from Burma.
The Mahamuni image was taken away by the Burmese as war loot. Thus, an expansionist Burma came into direct territorial contact with territories of the British East India Company, which set the stage for future flaring of hostility. Various geopolitical issues gave rise to the First Anglo-Burmese War; as the image of Mahamuni had been taken as war loot by the Burmese, this time the huge bell of the temple was taken by the British Army and awarded to a soldier, Bhim Singh, a Risaldar in British East India Company's 2nd Division of the British, for his bravery. This inscribed huge bell is still installed in a Mandir at village Nadrai near Kasganj town in present-day Kanshiram Nagar District of Uttar Pradesh India. In the Treaty of Yandabo, which ended hostilities, Burma was forced to cede Arakan alongside Tanintharyi to British India; the British made Akyab the capital of Arakan. Arakan became part of the province of Burma of the British Indian Empire, part of British Burma when Burma was made into a separate crown colony.
Arakan was administratively divided into three districts along traditional divisions during the Mrauk U period. Rakhine was the sit
A ranch is an area of land, including various structures, given to the practice of ranching, the practice of raising grazing livestock such as cattle or sheep for meat or wool. The word most applies to livestock-raising operations in Mexico, the Western United States and Western Canada, though there are ranches in other areas. People who own or operate a ranch are called cattlemen, or stockgrowers. Ranching is a method used to raise less common livestock such as elk, American bison or ostrich and alpaca. Ranches consist of large areas, but may be of nearly any size. In the western United States, many ranches are a combination of owned land supplemented by grazing leases on land under the control of the federal Bureau of Land Management or the United States Forest Service. If the ranch includes arable or irrigated land, the ranch may engage in a limited amount of farming, raising crops for feeding the animals, such as hay and feed grains. Ranches that cater to tourists are called guest ranches or, colloquially, "dude ranches."
Most working ranches do not cater to guests, though they may allow private hunters or outfitters onto their property to hunt native wildlife. However, in recent years, a few struggling smaller operations have added some dude ranch features, such as horseback rides, cattle drives or guided hunting, in an attempt to bring in additional income. Ranching is part of the iconography of the "Wild West" as seen in Western rodeos; the person who owns and manages the operation of a ranch is called a rancher, but the terms cattleman, stockgrower, or stockman are sometimes used. If this individual in charge of overall management is an employee of the actual owner, the term foreman or ranch foreman is used. A rancher who raises young stock sometimes is called a cow-calf operator or a cow-calf man; this person is the owner, though in some cases where there is absentee ownership, it is the ranch manager or ranch foreman. The people who are employees of the rancher and involved in handling livestock are called a number of terms, including cowhand, ranch hand, cowboy.
People involved with handling horses are sometimes called wranglers. Ranching and the cowboy tradition originated in Spain, out of the necessity to handle large herds of grazing animals on dry land from horseback. During the Reconquista, members of the Spanish nobility and various military orders received large land grants that the Kingdom of Castile had conquered from the Moors; these landowners were to defend the lands put into their control and could use them for earning revenue. In the process it was found that open-range breeding of sheep and cattle was the most suitable use for vast tracts in the parts of Spain now known as Castilla-La Mancha and Andalusia; when the Conquistadors came to the Americas in the 16th century, followed by settlers, they brought their cattle and cattle-raising techniques with them. Huge land grants by the Spanish government, part of the hacienda system, allowed large numbers of animals to roam over vast areas. A number of different traditions developed related to the original location in Spain from which a settlement originated.
For example, many of the traditions of the Jalisco charros in central Mexico come from the Salamanca charros of Castile. The vaquero tradition of Northern Mexico was more organic, developed to adapt to the characteristics of the region from Spanish sources by cultural interaction between the Spanish elites and the native and mestizo peoples; as settlers from the United States moved west, they brought cattle breeds developed on the east coast and in Europe along with them, adapted their management to the drier lands of the west by borrowing key elements of the Spanish vaquero culture. However, there were cattle on the eastern seaboard. Deep Hollow Ranch, 110 miles east of New York City in Montauk, New York, claims to be the first ranch in the United States, having continuously operated since 1658; the ranch makes the somewhat debatable claim of having the oldest cattle operation in what today is the United States, though cattle had been run in the area since European settlers purchased land from the Indian people of the area in 1643.
Although there were substantial numbers of cattle on Long Island, as well as the need to herd them to and from common grazing lands on a seasonal basis, the cattle handlers lived in houses built on the pasture grounds, cattle were ear-marked for identification, rather than being branded. The only actual "cattle drives" held on Long Island consisted of one drive in 1776, when the island's cattle were moved in a failed attempt to prevent them from being captured by the British during the American Revolution, three or four drives in the late 1930s, when area cattle were herded down Montauk Highway to pasture ground near Deep Hollow Ranch; the prairie and desert lands of what today is Mexico and the western United States were well-suited to "open range" grazing. For example, American bison had been a mainstay of the diet for the Native Americans in the Great Plains for centuries. Cattle and other livestock were turned loose in the spring after their young were born and allowed to roam with little supervision and no fences rounded up in the fall, with the mature animals driven to market and the breeding stock brought close to the ranch headquarters for greater protection in the winter.
The use of livestock branding allowed the cattle owned by different ranchers to be identified and sorted. Beginning with the settlement of Texas in the 1840s, expansion both north and west from that time, through the Civil War and into the 1880s, ranching dominated wes
Myanmar the Republic of the Union of Myanmar and known as Burma, is a country in Southeast Asia. Myanmar is bordered by India and Bangladesh to its west and Laos to its east and China to its north and northeast. To its south, about one third of Myanmar's total perimeter of 5,876 km forms an uninterrupted coastline of 1,930 km along the Bay of Bengal and the Andaman Sea; the country's 2014 census counted the population to be 51 million people. As of 2017, the population is about 54 million. Myanmar is 676,578 square kilometres in size, its capital city is Naypyidaw, its largest city and former capital is Yangon. Myanmar has been a member of the Association of Southeast Asian Nations since 1997. Early civilisations in Myanmar included the Tibeto-Burman-speaking Pyu city-states in Upper Burma and the Mon kingdoms in Lower Burma. In the 9th century, the Bamar people entered the upper Irrawaddy valley and, following the establishment of the Pagan Kingdom in the 1050s, the Burmese language and Theravada Buddhism became dominant in the country.
The Pagan Kingdom fell. In the 16th century, reunified by the Taungoo dynasty, the country was for a brief period the largest empire in the history of Mainland Southeast Asia; the early 19th century Konbaung dynasty ruled over an area that included modern Myanmar and controlled Manipur and Assam as well. The British took over the administration of Myanmar after three Anglo-Burmese Wars in the 19th century and the country became a British colony. Myanmar was granted independence as a democratic nation. Following a coup d'état in 1962, it became a military dictatorship under the Burma Socialist Programme Party. For most of its independent years, the country has been engrossed in rampant ethnic strife and its myriad ethnic groups have been involved in one of the world's longest-running ongoing civil wars. During this time, the United Nations and several other organisations have reported consistent and systematic human rights violations in the country. In 2011, the military junta was dissolved following a 2010 general election, a nominally civilian government was installed.
This, along with the release of Aung San Suu Kyi and political prisoners, has improved the country's human rights record and foreign relations, has led to the easing of trade and other economic sanctions. There is, continuing criticism of the government's treatment of ethnic minorities, its response to the ethnic insurgency, religious clashes. In the landmark 2015 election, Aung San Suu Kyi's party won a majority in both houses. However, the Burmese military remains a powerful force in politics. Myanmar is a country rich in jade and gems, natural gas and other mineral resources. In 2013, its GDP stood at its GDP at US$221.5 billion. The income gap in Myanmar is among the widest in the world, as a large proportion of the economy is controlled by supporters of the former military government; as of 2016, Myanmar ranks 145 out of 188 countries in human development, according to the Human Development Index. Both the names Myanmar and Burma derive from the earlier Burmese Mranma, an ethnonym for the majority Bamar ethnic group, of uncertain etymology.
The terms are popularly thought to derive from "Brahma Desha" after Brahma. In 1989, the military government changed the English translations of many names dating back to Burma's colonial period or earlier, including that of the country itself: "Burma" became "Myanmar"; the renaming remains a contested issue. Many political and ethnic opposition groups and countries continue to use "Burma" because they do not recognise the legitimacy of the ruling military government or its authority to rename the country. In April 2016, soon after taking office, Aung San Suu Kyi clarified that foreigners are free to use either name, "because there is nothing in the constitution of our country that says that you must use any term in particular"; the country's official full name is the "Republic of the Union of Myanmar". Countries that do not recognise that name use the long form "Union of Burma" instead. In English, the country is popularly known as either "Burma" or "Myanmar". Both these names are derived from the name of the majority Burmese Bamar ethnic group.
Myanmar is considered to be the literary form of the name of the group, while Burma is derived from "Bamar", the colloquial form of the group's name. Depending on the register used, the pronunciation would be Myamah; the name Burma has been in use in English since the 18th century. Burma continues to be used in English by the governments of countries such as the United Kingdom. Official United States policy retains Burma as the country's name, although the State Department's website lists the country as "Burma" and Barack Obama has referred to the country by both names; the government of Canada has in the past used Burma, such as in its 2007 legislation imposing sanctions, but as of the mid-2010s uses Myanmar. The Czech Republic uses Myanmar, although its Ministry of Foreign Affairs mentions both Myanmar and Burma on its website; the United Nations uses Myanmar, as do the Association of Southeast Asian Nations, Russia, China, Bangladesh, Norway and Switzerland. Most English-speaking international news media refer to the country by the name Myanmar, including the BBC, CNN, Al Jazeera and the Australian Broadcasting Corporation /Ra
Soil mechanics is a branch of soil physics and applied mechanics that describes the behavior of soils. It differs from fluid mechanics and solid mechanics in the sense that soils consist of a heterogeneous mixture of fluids and particles but soil may contain organic solids and other matter. Along with rock mechanics, soil mechanics provides the theoretical basis for analysis in geotechnical engineering, a subdiscipline of civil engineering, engineering geology, a subdiscipline of geology. Soil mechanics is used to analyze the deformations of and flow of fluids within natural and man-made structures that are supported on or made of soil, or structures that are buried in soils. Example applications are building and bridge foundations, retaining walls and buried pipeline systems. Principles of soil mechanics are used in related disciplines such as engineering geology, geophysical engineering, coastal engineering, agricultural engineering and soil physics; this article describes the genesis and composition of soil, the distinction between pore water pressure and inter-granular effective stress, capillary action of fluids in the soil pore spaces, soil classification and permeability, time dependent change of volume due to squeezing water out of tiny pore spaces known as consolidation, shear strength and stiffness of soils.
The shear strength of soils is derived from friction between the particles and interlocking, which are sensitive to the effective stress. The article concludes with some examples of applications of the principles of soil mechanics such as slope stability, lateral earth pressure on retaining walls, bearing capacity of foundations; the primary mechanism of soil creation is the weathering of rock. All rock types may be broken down into small particles to create soil. Weathering mechanisms are physical weathering, chemical weathering, biological weathering Human activities such as excavation and waste disposal, may create soil. Over geologic time buried soils may be altered by pressure and temperature to become metamorphic or sedimentary rock, if melted and solidified again, they would complete the geologic cycle by becoming igneous rock. Physical weathering includes temperature effects and thaw of water in cracks, wind and other mechanisms. Chemical weathering includes dissolution of matter composing a rock and precipitation in the form of another mineral.
Clay minerals, for example can be formed by weathering of feldspar, the most common mineral present in igneous rock. The most common mineral constituent of silt and sand is quartz called silica, which has the chemical name silicon dioxide; the reason that feldspar is most common in rocks but silica is more prevalent in soils is that feldspar is much more soluble than silica. Silt and Gravel are little pieces of broken rocks. According to the Unified Soil Classification System, silt particle sizes are in the range of 0.002 mm to 0.075 mm and sand particles have sizes in the range of 0.075 mm to 4.75 mm. Gravel particles are broken pieces of rock in the size range 4.75 mm to 100 mm. Particles larger than gravel are called boulders. Soil deposits are affected by the mechanism of deposition to their location. Soils that are not transported are called residual soils—they exist at the same location as the rock from which they were generated. Decomposed granite is a common example of a residual soil.
The common mechanisms of transport are the actions of gravity, ice and wind. Wind blown soils include dune loess. Water carries particles of different size depending on the speed of the water, thus soils transported by water are graded according to their size. Silt and clay may settle out in a lake, gravel and sand collect at the bottom of a river bed. Wind blown soil deposits tend to be sorted according to their grain size. Erosion at the base of glaciers is powerful enough to pick up large rocks and boulders as well as soil. Gravity on its own may carry particles down from the top of a mountain to make a pile of soil and boulders at the base; the mechanism of transport has a major effect on the particle shape. For example, low velocity grinding in a river bed will produce rounded particles. Freshly fractured colluvium particles have a angular shape. Silts and gravels are classified by their size, hence they may consist of a variety of minerals. Owing to the stability of quartz compared to other rock minerals, quartz is the most common constituent of sand and silt.
Mica, feldspar are other common minerals present in sands and silts. The mineral constituents of gravel may be more similar to that of the parent rock; the common clay minerals are montmorillonite or smectite and kaolinite or kaolin. These minerals tend to form in sheet or plate like structures, with length ranging between 10−7 m and 4x10−6 m and thickness ranging between 10−9 m and 2x10−6 m, they have a large specific surface area; the specific surface area is defined as the ratio of the surface area of particles to the mass of the particles. Clay minerals have specific surface areas in the range of 10 to 1,000 square meters per gram of solid. Due to the large surface area available for chemical and van der Waals interaction, the mechanical behavior of clay minerals is sensitive to the amount of pore fluid available and the type and amount of dissolved ions in the pore fluid. To