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History of Indonesia

Monday, July 30, 2012 0 comments
The History of Indonesia was shaped by its geographic position, its natural resources, the series of human migrations, contacts, economy and trade, conquests and politics. Indonesia is an archipelagic country of 17,508 islands (6,000 inhabited) stretching along the equator in South East Asia. The country's strategic sea-lane position fostered inter-island and international trade; trade has since fundamentally shaped Indonesian history. The area of Indonesia is populated by peoples of various migrations, creating a diversity of cultures, ethnicities, and languages. The archipelago's landforms and climate significantly influenced agriculture and trade, and the formation of states.

Fossilised remains of Homo erectus and his tools, popularly known as the "Java Man", suggest the Indonesian archipelago was inhabited by at least 1.5 million years ago. Austronesian people, who form the majority of the modern population, are thought to have originally been from Taiwan and arrived in Indonesia around 2000 BCE. From the 7th century CE, the powerful Srivijaya naval kingdom flourished bringing Hindu and Buddhist influences with it. The agricultural Buddhist Sailendra and Hindu Mataram dynasties subsequently thrived and declined in inland Java. The last significant non-Muslim kingdom, the Hindu Majapahit kingdom, flourished from the late 13th century, and its influence stretched over much of Indonesia. The earliest evidence of Islamised populations in Indonesia dates to the 13th century in northern Sumatra; other Indonesian areas gradually adopted Islam which became the dominant religion in Java and Sumatra by the end of the 16th century. For the most part, Islam overlaid and mixed with existing cultural and religious influences.

Europeans arrived in Indonesia from the 16th century seeking to monopolise the sources of valuable nutmeg, cloves, and cubeb pepper in Maluku. In 1602 the Dutch established the Dutch East India Company (VOC) and became the dominant European power. Following bankruptcy, the VOC was formally dissolved in 1800, and the government of the Netherlands established the Dutch East Indies as a nationalised colony. By the early 20th century Dutch dominance extended to what was to become Indonesia's current boundaries. The Japanese invasion and subsequent occupation during WWII ended Dutch rule, and encouraged the previously suppressed Indonesian independence movement. Two days after the surrender of Japan in August 1945, nationalist leader, Sukarno, declared independence and was appointed president. The Netherlands tried to reestablish their rule, but a bitter armed and diplomatic struggle ended in December 1949, when in the face of international pressure, the Dutch formally recognised Indonesian independence.

An attempted coup in 1965 led to a violent army-led anti-communist purge in which over half a million people were killed. General Suharto politically outmanoeuvred President Sukarno, and was formally appointed president in March 1968. His New Order administration garnered the favour of the West whose investment in Indonesia was a major factor in the subsequent three decades of substantial economic growth. In the late 1990s, however, Indonesia was the country hardest hit by the East Asian Financial Crisis which led to popular protests and Suharto's resignation on 21 May 1998. The Reformasi era following Suharto's resignation, has led to a strengthening of democratic processes, including a regional autonomy program, the secession of East Timor, and the first direct presidential election in 2004. Political and economic instability, social unrest, corruption, natural disasters, and terrorism have slowed progress. Although relations among different religious and ethnic groups are largely harmonious, acute sectarian discontent and violence remain problems in some areas.

http://en.wikipedia.org/wiki/History_of_Indonesia

How Airplanes Work

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Human flight has become a tired fact of modern life. At any given moment, roughly 5,000 airplanes crisscross the skies above the United States alone, amounting to an estimated 64 million commercial and private takeoffs every year [source: NATCA]. Consider the rest of the world's flight activity, and the grand total is incalculable.

It is easy to take the physics of flight for granted, as well as the ways in which we exploit them to achieve flight. We often glimpse a plane in the sky with no greater understanding of the principles involved than a caveman.
How do these heavy machines take to the air? To answer that question, we have to enter the world of fluid mechanics.

Physicists classify both liquids and gases as fluids, based on how they flow. Even though air, water and pancake syrup may seem like very different substances, they all conform to the same set of mathematical relationships. In fact, basic aerodynamic tests are sometimes performed underwater. To put it simply, a salmon essentially flies through the sea, and a pelican swims through the air.

The core of the matter is this: Even a clear sky isn't empty. Our atmosphere is a massive fluid layer, and the right application of physics makes it possible for humans to traverse it.
In this article, we'll walk through the basic principles of aviation and the various forces at work in any given flight.

how to steam generators work

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Heat Exchange

  • Steam generators are used to harness energy liberated as heat in a wide variety of processes and convert it into a form which is more useful, such as mechanical and electrical energy. The heat used is typically produced intentionally for the production of electricity or is captured as a byproduct of some other industrial process. The immediate source of the heat is usually dirty, such as the radioactive fuel in a nuclear power plant, so the first step of steam power generation is to transfer that heat into clean water with a heat exchanger. This is done by having the heat source elevate the temperature of an exchange medium, such as an oil, that is circulated in a closed circuit. The oil in turn heats a water reservoir without contaminating it.

Steam Generation

  • The hot oil is circulated through a water bath to generate steam. There are several different geometrical schemes for doing this, but the principle remains the same. The heating liquid is diverted into many smaller pipes to increase its surface contact with the water and facilitate rapid heat exchange and steam production. The steam produced in modern nuclear and coal power plants is often at supercritical conditions, or above the critical point in water's phase diagram (374 degrees Celsius and 22 MPa).

Conversion of Heat to Electricity

  • Supercritical steam is overloaded with energy. Steam's energy is converted into mechanical energy by forcing it through a steam turbine. The high pressure of the steam pushes on the many angled blades of the turbine, causing the shaft to rotate. This mechanical energy is converted to electricity by using the power form the rotating shaft to turn an electrical generator. The turbine being built in the image may generate up to 65 megawatts of electricity.


how to diesel engines work

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O­ne of the most popular HowStuffWorks articles is How Car Engines Work, which explains the basic principles behind internal combustion, discusses the four-stroke cycle and talks about all of the subsystems that help your car's engine to do its job. For a long time after we published that article, one of the most common questions asked (and one of the most frequent suggestions made in the suggestion box) was, "What is the difference between a gasoline and a diesel engine?"

Diesel's story actually begins with the invention of the gasoline engine. Nikolaus August Otto had invented and patented the gasoline engine by 1876. This invention used the four-stroke combustion principle, also known as the "Otto Cycle," and it's the basic premise for most car engines today. In its early stage, the gasoline engine wasn't very efficient, and other major methods of transportation such as the steam engine fared poorly as well. Only about 10 percent of the fuel used in these types of engines actually moved a vehicle. The rest of the fuel simply produced useless heat.

I­n 1878, Rudolf Diesel was attending the Polytechnic High School of Germany (the equivalent of an engineering college) when he learned about the low efficiency of gasoline and steam engines. This disturbing information inspired him to create an engine with a higher efficiency, and he devoted much of his time to developing a "Combustion Power Engine." By 1892 Diesel had obtained a patent for what we now call the diesel engine.
­If diesel engines are so efficient, why don't we use them more often? You might see the words "diesel engine" and think of big, hefty cargo trucks spewing out black, sooty smoke and creating a loud clattering noise. This negative image of diesel trucks and engines has made diesel less attractive to casual drivers in the United States -- although diesel is great for hauling large shipments over long distances, it hasn't been the best choice for everyday commuters. This is starting to change, however, as people are improving the diesel engine to make it cleaner and less noisy.

If you haven't already done so, you'll probably want to read How Car Engines Work first, to get a feel for the basics of internal combustion. But hurry back -- in this article, we unlock the secrets of the diesel engine and learn about some new advancements.

Foods That Cause Acne

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Foods That Cause Acne. Acne is one of the most hated enemy by everyone, especially women. Acne is not including a dangerous disease. But its presence is very annoying, though acne is not harmful but should we treat and handle well.
Acne is caused by clogged pores due to overactive oil glands. Although many medical experts who denied any connection between acne with the food we eat, there's no harm in avoiding some foods that supposedly can trigger acne.

Here are some foods can cause acne:

1. Sugar and Chocolate
Chocolate may be one of the most food trigger acne. Archives of Dermatology published a study which explains that the food has a high Glycemic Index scale, usually in processed carbohydrates such as sugar can cause the appearance of acne due to increased hormone levels.

2. Milk
Some studies show a high milk intake may be associated with the appearance of acne. A Harvard study found that teens who drink milk more than two servings a day are more likely to suffer from severe acne. That is because the increase in growth hormone which causes the sebaceous glands in the skin become clogged.

3. Iodine
Iodine may be one factor in the appearance of acne, such as skin oil glands which can irritate skin that is prone to acne. Iodine can be found in fish and shellfish because sea water contains iodine. In addition other sources comes from iodized salt which is a component of several types of canned food.

4.Caffeine and Alcohol
Caffeine is considered to trigger the appearance of acne because it can affect hormone levels produced by the body. Some sources of caffeine are coffee, tea, soft drinks, and chocolate. In addition, alcohol also causes an increase in hormones, particularly testosterone can cause acne more often.

5. Food Allergy Triggers
Skin problems often arise due to food allergies, especially milk and eggs. Acne appears due to the immune system tries to fight the poison that is felt. An allergist has diagnosed and confirmed the relationship of food allergy with severe acne.

6. Fruit and Vegetable Characteristically Acid
Some fruits and vegetables that are acidic can cause the appearance of acne, such as carrots, cucumbers, oranges, and lettuce. The acidity of the body can cause the appearance of acne, because it should be avoided.

Those are some foods that can trigger the onset of Acne.

 
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