What's Blog?

A blog (a portmanteau of the term web log) is a discussion or informational site published on the World Wide Web and consisting of discrete entries ("posts") typically displayed in reverse chronological order (the most recent post appears first). Until 2009 blogs were usually the work of a single individual, occasionally of a small group, and often were themed on a single subject. More recently "multi-author blogs" (MABs) have developed, with posts written by large numbers of authors and professionally edited. MABs from newspapers, other media outlets, universities, think tanks, interest groups and similar institutions account for an increasing quantity of blog traffic. The rise of Twitter and other "microblogging" systems helps integrate MABs and single-author blogs into societal newstreams. Blog can also be used as a verb, meaning to maintain or add content to a blog.

The emergence and growth of blogs in the late 1990s coincided with the advent of web publishing tools that facilitated the posting of content by non-technical users. (Previously, a knowledge of such technologies as HTML and FTP had been required to publish content on the Web.)

A majority are interactive, allowing visitors to leave comments and even message each other via GUI widgets on the blogs, and it is this interactivity that distinguishes them from other static websites. In that sense, blogging can be seen as a form of social networking. Indeed, bloggers do not only produce content to post on their blogs, but also build social relations with their readers and other bloggers.There are high-readership blogs which do not allow comments, such as Daring Fireball.

Many blogs provide commentary on a particular subject; others function as more personal online diaries; others function more as online brand advertising of a particular individual or company. A typical blog combines text, images, and links to other blogs, Web pages, and other media related to its topic. The ability of readers to leave comments in an interactive format is an important contribution to the popularity of many blogs. Most blogs are primarily textual, although some focus on art (art blogs), photographs (photoblogs), videos (video blogs or "vlogs"), music (MP3 blogs), and audio (podcasts). Microblogging is another type of blogging, featuring very short posts. In education, blogs can be used as instructional resources. These blogs are referred to as edublogs.

As of 16 February 2011, there were over 156 million public blogs in existence. On October 13, 2012, there were around 77 million Tumblr and 56.6 million WordPress blogs in existence worldwide. According to critics and other bloggers, Blogger is the most popular blogging service used today.

Overview

Online diaries have existed since at least 1994. As a community formed, these publications came to be almost exclusively known as online journals. Today they are almost exclusively called blogs, though some differentiate by calling them personal blogs. The running updates of online diarists combined with links inspired the term 'web log' which was eventually contracted to form the word 'blog'.

In online diaries, people write about their day-to-day experiences, social commentary, complaints, poems, prose, illicit thoughts and any content that might be found in a traditional paper diary or journal. They often allow readers to contribute through comments or community posting.

Early history

The first web page in an online-diary format is thought to be Claudio Pinhanez's "Open Diary", which was published at the MIT Media Lab website from 14 November 1994 until 1996.^[1] Other early online diarists include Justin Hall, who began eleven years of personal online diary-writing in 1994,^[2] Carolyn Burke, who started publishing "Carolyn's Diary"^[3] on 3 January 1995, Bryon Sutherland, who announced his diary The Semi-Existence of Bryon in a USENET newsgroup on 19 April 1995,^[4] and David Siegel, who started his journal^[5] on 30 August 1995.

Online diaries soon caught the attention of the media with the publication of the book 24 Hours in Cyberspace (1996) which captured personal profiles of the people involved in early web pages. The earliest book-length scholarly discussion of online diaries is Philippe Lejeune's Cher écran, ("Dear Screen", not yet translated to English).^[6]

The end of 1997 is generally considered the cut-off date for early adopters.^[7]

In 1998, Simon Firth described in Salon magazine^[8] how many early online diarists were abandoning the form. And yet, he said, "While many of the movement's pioneers may be tired and disillusioned, the genre shows plenty of signs of life -- of blossoming, even, into something remarkable: a new literary form that allows writers to connect with readers in an excitingly new way."

Formation of a community

As diarists (sometimes called escribitionists) began to learn from each other, several Webrings formed to connect the various diaries and journals. The most popular Webring was Open Pages, which started in July 1996 and had 537 members as of 20 October 1998. A community website called Diarist.Net was formed and awarded "The Diarist Awards" quarterly from 1999 through 2004. There were a number of lists of diaries and journals by topic, called "'burbs", which allowed people to find sites that had some correlation to each other.^[9]

Mailing lists helped solidify the community. "Collabs" were collaborative projects in which people wrote on given topics and subjects.

Technologies

Some early diaries and journals showcased different emerging internet technologies, including interactive message forums, online stores, RealAudio, RealVideo, live webcams, notify lists, and daily self-photographs.^[10]

Today's diaries and journals may feature podcasts, trackBacks, permalinks, blogrolls and a host of other cutting-edge technologies.

Lifestyle

The formation of diary hosting websites such as Open Diary, Diary-X, Xanga, Femmunity and LiveJournal caused an explosive proliferation of online diaries and journals. Today, interactive online diaries, online journals, personal blogs and group blogs are integrated into the daily lives of many teenagers and college students, with communications between friends playing out online. Even fights may be posted in the diaries, with not-so-veiled insults of each other easily readable by all their friends, enemies, and complete strangers.

Personal opinions on experiences and hobbies are very common in the blog world. Blogs have given the opportunity for people to express their views to a mass audience.

In October 2006, the History Matters campaign, a 2006 joint project by the major heritage organizations in England and Wales, conducted the One Day in History project, asking residents of the UK to write an online diary of what they did on 17 October 2006. The diaries were stored at the British Library from November

THE ALCHEMY

Alchemy is an ancient pseudoscience concerned with the transmutation of base metals into gold and with the discovery of both a single cure for all diseases and a way to prolong life indefinitely. Alchemy emerged as a pseudoscience in China an in Egypt during the early centuries of this era. In China it was associated with Taoist philosophy and purported to transmute base metals into gold by use of a “medicine”. The gold so produced was thought to have the ability to cure diseases and to prolong life. The mystical element was always strong in alchemy and became dominant with time so that in China degenerated into a complex of superstitions.

In Egypt, the methods of transmutation of metals were kept secret by temple priests. Those recipes became widely known at academy in Alexandria. Alchemy had its basis in the skills of Egyptian artisan, Eastern mysticism and Aristotelian theory of composition of matter. Aristotle taught that all matter was composed of four elements: water, earth, fire and air. According to this theory, different materials found in nature had different ratios of these four elements. Therefore, by proper treatment a base metal could be changed into gold. These ideas were further supported by astrological speculation from Mesopotamia.

THE SOLAR ENERGY

Solar energy is a term that encompasses a broad range of energy forms. The sun's energy profoundly affects the world's wind patterns, causes ocean water to evaporate as part of the hydraulic cycle and is essential for plant growth. The winds may be used to turn windmills, the hydraulic cycle makes hydroelectric power possible. Vegetation, which grows in the presence of sunlight, may be burned directly for instance, as wood in a stove or fireplace. Solar energy also makes it possible to harness ocean thermal energy, which uses the temperature difference between sun-warmed surface water and cold water from the ocean depths to produce power.

Although all these indirect means of using energy from the sun are considered solar technologies, the solar energy most commonly refers to direct use of the sun's energy: by means of photovoltaic sollar cells, which convert sunlight into electricity. It includes the use of various devices to convert solar radiation to heat the may be used for heating and cooling buildings, providing hot water for homes, business, industry and generating electricity by thermal means.

Besides the direct conversion of sunlight into electricity by means of photovoltaic cells, sunlight may be used to generate steam, which can then be used to power a turbine for producing electricity. One solar-thermal design, called a power tower, consists of a field of movable mirrors that surround a tower, at the top of which is a boiler. The mirrors, called heliostats, track the sun so as to constantly focus its light on the boiler. At the bottom of the tower is a building that houses a turbine generator. Some scientists heve suggested building huge photovoltaic arrays in earth orbit for producing large amounts of power. Such arrays, called solar space power satellites, would beam collected energy to earth by way of microwaves.

THE HUMAN DIGESTION

Digestion is the process in which nutrients such as proteins, fats and carbohydrates are taken in by an organism and broken down to a form that may be readily absorbed from the gut for circulation to and used by various cells. The host is provided with nutrient required for metabolism. Nutrient supply the molecules from which energy, as calories, may be derived for cellular synthesis, cell and organ growth, and tissue replacement. In addition, nutrient provide the components that are needed in these processes but which the host is unable to synthesize, such as vitamins, minerals and certain essential amino acids.

Food enters the digestive tract by way of the mouth, where it undergoes physical change through chewing. Enzymes, such as ptyalin, that initiate sugar digestion are introduced in salivary secretions, which also provide lubrication to facilitate chewing and swallowing.

The food bolus (soft mass) passes through the esophagus and is retained in the stomach. There food is liquefied by a mixture of hydrochloric acid and pepsin, which is secreted by the stomach wall.

A common duct from the pancreas and the gall bladder into the duodenum serves as a conduit to introduce bicarbonate (to neutralize hydrochloric acid), pancreatic enzymes (for degradation of proteins and carbohydrates) and bile salts (for fat absorption).

Peristalsis moves the chyme into the next portion of small intestine, where the bulk of digested carbohydrate, protein, water, water-soluble vitamins and minerals are absorbed. Remaining nutrients are propelled to the last third of the small intestine, the ileum.

Here fat, fat-soluble vitamins and bile salts are absorbed.

PLASTIC ARTICLES

A plastic material is one which can be moulded into the shape we want. The first plastic materials were ones that are to be found in nature, such as wax, resin and clay. We know that clay can be fashioned into cups and saucers.

Today are chemists have found out to make new materials which can be pressed into whatever shapes are wanted and then made hard so that they can be used by us.

There are several kinds of stuffs, but they all fall into one or other of two groups. Those in one group are put while cold into a metal mould of the right shape. They are pressed into shape and then made hard by heat. Once they harden they keep their shape. The other group is made soft by heat. Then it is squirted as a thick liquid into a metal mould of the right shape. The plastic become firm in their new shape as they cool.

Let us take a simple article as a plastic tumbler, which is shaped like a glass. For this they use the method known as compression mould. A metal mould of the shape of the outside of the tumbler is made and into this some plastic material is put. It is in the form of a powder. Then another metal mould, having the shape of the inside of the tumbler, comes down and pressed into this powder. The powder spreads out and fills the space between the inner and outer mould. The mould get very hot and the powder joins together to form a firm tumbler.

When the top mould is lifted up, the tumbler can be taken out. It will always keeps the same shape.

Another method, called injection moulding is used to make plastic toys. A metal mould has in it a hollow space in the shape of a toy. The plastic material is heated and it turns to a thick liquid. This liquid is squirted into the hollow space shaped like a toy. It fills up this space, and when the liquid cools and becomes hard it is now in the form of a toy.

VOLCANO

A volcano is a vent in the earth from which molten rock and gas erupt. The molten rock that erupts from the volcano forms a hill or mountain around the vent. The lava may flow out as a viscous liquid, or it may be exploded from the vent as solid or liquid particles.

The most fluid magmas are erupted quietly. They flow from the vent to form gently sloping shield volcanoes. The lava flows from the shield volcanoes are usually only 1 to 10 meter thick. They may extend for great distances away from the vent.

Magmas with high gas contents and high viscousities are usually more explosive. These gas-rich magmas are blown high into the air during an eruption. The magma falls as volcanic bombs, which accumulate around the vent. They form steep-sided cinder cones.

Most of the tallest volcanoes are stratovolcanoes. These form from a cycle of quiet eruptions of fluid lava followed by explosive eruptions of viscous lava.

A volcano may exhibit different styles of eruptions at different times. Eruptions may change from one type to another as the eruption progresses. The least violent type of eruption is termed Hawaiian. It is characterized by extensive fluid lava flows from central vents. Occasionally it is accompanied by lava fountains. Strombolian eruptions are characterized by moderately fluid lava flows. Vulcanian eruptions are marked by viscous magmas.

Volcanic activity has yielded a variety of economic resources. Volcanoes supply both lightweight and heavy aggregate, as well as pumice for abrasives and elements such as sulfur, copper and many other. Recently volcanic areas have become important sources of geothermal energy.

PETROLEUM

Petroleum – the oil and gas in the earth crust – is the immense importance to humans. Petroleum occurs widely in the sedimentary rocks of the earth's crust. It may as gas, liquid, semisolid or solid, although mixtures of gas and liquids are most common.

Petroleum is a complex mixture of hydro carbon compounds with minor amounts of nitrogen, oxygen and sulfur as impurities. Forms of petroleum include crude oil. Natural gas consisting of the compound methane, butane and propane. Asphalt is obtained as a residue from certain petroleum. Commercially, crude oil is the most important form of petroleum and natural gas is second.

Petroleum is enormously important from an economic, technological and social standpoint. Fuels that derived from petroleum supply more than half of the world's total supply of energy. Gasoline, kerosene and diesel oil provide fuel for automobiles, tractors, trucks, aircraft and ships. Fuel oil and natural gas are used to heat homes and commercial buildings.

Petroleum products are used in the manufacture of synthetic fibers for clothing and in plastics, paints, fertilizers, insecticides, soaps and synthetic rubber. The uses of petroleum as a source of raw material in manufacturing have progressively increased in importance.

FROM ALCHEMY TO SCIENCE

In the time of Aristotle, greeks spread into Egypt and Mesopotamia. And so, in the centuries that followed, the knowledge of those regions met and mixed with Greeks theories.

For instance, Egyptian metalworkers knew how to make imitation gold by mixing copper with other metals. The mixture wasn't gold, of course, but it had the color of gold. However, a Greeks theory said that gold and copper were really made of the same matter. They differed only in the “form”. So it followed that one could make gold from copper or even from lead.

Naturally, metalworkers began to try to make real gold. This was probably the beginning of a study called chemia. Exactly where this word comes from no one knows, but it is the root of our word “chemistry”.

For many centuries the students of chemia tried to make gold out of other metals. But since this was impossible by the methods they used, they always failed.

As time passed, the Arabs became great conquerors. They won control of Mesopotamia and Egypt and much more. And they took up the study of chemia, which they called al chemia (al is Arabic for “the”). This expression has come down to us as “alchemy”.

The most important Arabian alchemist was Jabir ibn Hayyan. He lived about A.D. 750 and is also known by the Latin form of his name, Geber. He seems to have made a number of discoveries about ways to prepare chemical. And it it was he who started the search for certain dry powder that came to be called the philosopher's stone. Alchemists believed that it would turn other metals into gold. And they searched for it during hundreds of years.

Arabian alchemists did discover some important new chemical substance. Among these were ammonium chloride and certain strong alkalies. Most of their time, however, was spent searching for the philosopher stone. And after the year 1000, Arabian alchemy came to an end.

However, by the 1100's Arabian books were reaching Europe. Books an alchemy (and many more) were translated into Latin. Europeans the began to search for the philosopher's stone.

Fortunatelly by the 1500's a new spirit was on the sea. There was a swiss doctor who called himself Paracelsus. He was an alchemist but not an ordinary one. He didn't think it was at all important to find methods for making gold. He thought alchemists should search for medicine to cure sickness. He was not a great scientist and some of his idea were entirely wrong. But he wanted to put an end to ancient belief's and start over. There he was right. He was also right in waiting to test ideas by experiments.

Beginning in the 1580's an Italian scientist named Galileo showed that it was very important to make accurate measurements. More could be learned in this way than in any other. He work in physics and astronomy helped to establish modern science.

Lavoisier, a French chemist, explained that a candle didn't really disappear if it burned. The carbon and hydrogen in it combined with the oxygen of the air. They formed carbon dioxide gas and water vapour. If the candle burned in a closed vessel, the weight of the candle and vessel did not change.

Chemists tried to arrange the elements in the order of their atomic weights. The most successful arranger was a Russian chemist, Dmitri I. Mendeleev. In 1869 he arranged the elements in rows and columns. He published the first periodic table, which become the basis of theoritical chemistry. The periodic table provides an easy way to show the division of the elements into two acid and base.

As chemistry had been developing so had the science of physics. Physics deals with various forms of energy, such as heat, light, electricity and magnetism. From about 1850 on, chemists began to apply the findings physics to chemistry. In this way physical chemistry was developed.

THE AIR POLLUTION

Air pollution is the accumulation in the atmosphere of substances that, in sufficient concentrations, endanger human health or produce other measured effects on living matter and other materials.

Among the major sources of pollution are power and heat generation, the burning of solid wastes, industrial processes and especially transportation. The six major types of pollutants are carbon monoxide, hydro carbons, nitrogen oxides, particulates, sulfur dioxide and photochemical oxidants.

Smog has seriously affected more persons than any other type of air pollution. It can be loosely defined as a multisource, widespread air pollution that occurs in the air of cities.

As a coal economy has gradually been replaced by a petroleum economy, photochemical smog has become predominant in many cities. Its unpleasant properties result from the irradiation by sunlight of hydrocarbons and other pollutants in the air. Irradiation produces a long series of photochemical reactions. The product of the reactions include organic particles, ozone, aldehydes and organic acids. Sulfur dioxide, which is always present to some extent, oxidizes and hydrates to form sulfuric acid and becomes part of the particulate matter. Automobiles are polluters even in the absence of photochemical reactions. They are responsible for much of the particulate material in the air. They also emit carbon monoxide, one of the most toxic constituents of smog.

All types of smog decrease visibility and with the possible exception of ice fog are irritating to the respiratory system.

Statistical studies indicate that smog is a contributor to malignancies of many types. Photochemical smog produces eye irritation and lacrimation and causes severe damage to many types of vegetation, including important crops. Acute effects include an increased mortality rate, especially among person suffering from respiratory and coronary ailment.

GENERATOR

A generator is a machine that converts mechanical energy into electrical energy by rotating an armature, which contains conductors, through a magnetic field. A voltage is induced in the moving conductors by an effect called electromagnetic induction. In order for voltage to be generated, relative motion must exist between the conductors and the magnetic field. An engine, motor, turbine or other source of mechanical energy is used to turn the armature shaft. Generators are built in many sizes. Most electricity used today in cars, in homes and by industry in producing things by generators.

The two main types of generators are direct-current (DC) generators and alternating-current (AC) generators. The DC generators rotates the conductors in a stationary magnetic field. The AC generators (alternator) rotates a magnetic field that is cut by the stationary conductors. Current induced in the conductors of all generators is an alternating-current. The current taken from the generator for the electrical load circuit, however, may be either AC or DC, depending on how the generator is constructed.

The strength of voltage induced in the conductor depends on its speed and on the strength of the magnetic field. The magnetic field may be furnished by a permanent magnet or by current flowing through field coils to form an electromagnet.

The principal components of a DC generator are the armature, commutator, field poles, brushes and brush rigging, yoke or frame, an bells or and frames. In an alternator, the armature coils are held in place in slots in the alternator frame. The field coils are wound on poles or slots around the rotating shaft. The assembly that contains the stationary conductors is called stator. The assembly that includes the rotating poles and field coils is called rotor.

ECOLOGY

Darwin's theory of evolution was essentially ecological. He postulated that organisms which will survive to reproduce are those that are best adapted to their environment. Ecologists are concerned with how organisms adapt to their environment in order to survive. The ecological functions of an organism are said to constitute its niche. For example, an insect may be a predator, but it may not prey on organisms much larger or much smaller than itself. Also, diurnal predators normally do not capture organisms that are nocturnal or that live in habitats unsuited to the predator.

Many ecologists are proponents of a principle called competitive exclusion, which states that each niche can be occupied by only one species, because when a required resource is limited and two or more species compete for it, one of the species will be eliminated unless it can evolve to occupy a slightly different niche.

One of the major trends in ecology is the increased use of mathematical modeling, which often requires the use of computers. Mathematical formulas are used to stimulate population fluctuations, mineral cycling and energy flow. Models can be used to discover where our knowledge is inadequate, to aid in making generalizations and formulating ecological principles and to help predict the fate of ecosystems under given sets of circumstances.

The growing field of systems ecology uses theoretical analysis and experimental methods to study the disruption of ecosystems and the dynamics of their reconstruction. System ecology requires people trained in a wide variety of disciplines: mathematics, computer technology, physiology, microbiology, biochemistry, climatology and taxonomy.

Ecologists are more and more involved in solving problems caused by increased human population, increased pollution, increased need for energy and increased attempts to destroy ecosystem for human use.