Artikel Fisika 1

Pemanfaatan Uranium Sebagai Bahan Bakar

Uranium adalah mineral yang memancarkan radiasi nuklir atau bersifat radioaktif, digunakan dalam berbagai bidang salah satunya adalah sebagai bahan bakar nuklir. Uranium merupakan suatu unsur kimia dalam tabel periodik yang memiliki lambang U dan nomor atom 92. Sebuah logam berat, beracun, berwarna putih keperakan dan radioaktif alami, uranium termasuk ke seri aktinida (actinide series). Uranium biasanya terdapat dalam jumlah kecil di bebatuan, tanah, air, tumbuhan, dan hewan (termasuk manusia).

Uranium memiliki 3 Isotop :

– U234 kadar sangat kecil

– U235 kadar 0,715 = 0,7 %

– U238 kadar 99,285 = 99,3%

Isotop U235 digunakan sebagai bahan bakar reaktor nuklir dan senjata nuklir.

Uranium memiliki sifat fisik yang khas :

– Ditemukan di alam dalam bentuk U3O atau UO berwarna hijau kekuning-kuningan dan coklat tua.

– Bila disinari cahaya ultra ungu, uranium akan mengeluarkan cahaya fluoresensi yang sangat indah

Dalam fisika nuklir, sebuah reaksi nuklir adalah sebuah proses di mana dua nuklei atau partikel nuklir bertubrukan, untuk memproduksi hasil yang berbeda dari produk awal. Pada prinsipnya sebuah reaksi dapat melibatkan lebih dari dua partikel yang bertubrukan, tetapi kejadian tersebut sangat jarang. Bila partikel-partikel tersebut bertabrakan dan berpisah tanpa berubah (kecuali mungkin dalam level energi), proses ini disebut tabrakan dan bukan sebuah reaksi.

Dikenal dua reaksi nuklir, yaitu reaksi fusi nuklir dan reaksi fisi nuklir. Reaksi fusi nuklir adalah reaksi peleburan dua atau lebih inti atom menjadi atom baru dan menghasilkan energi, juga dikenal sebagai reaksi yang bersih. Reaksi fisi nuklir adalah reaksi pembelahan inti atom akibat tubrukan inti atom lainnya, dan menghasilkan energi dan atom baru yang bermassa lebih kecil, serta radiasi elektromagnetik. Reaksi fusi juga menghasilkan radiasi sinar alfa, beta dan gamma yang sangat berbahaya bagi manusia.

Contoh reaksi fusi nuklir adalah reaksi yang terjadi di hampir semua inti bintang di alam semesta. Senjata bom hidrogen juga memanfaatkan prinsip reaksi fusi tak terkendali. Contoh reaksi fisi adalah ledakan senjata nuklir dan pembangkit listrik tenaga nuklir.

Unsur yang sering digunakan dalam reaksi fisi nuklir adalah Plutonium dan Uranium (terutama Plutonium-239, Uranium-235), sedangkan dalam reaksi fusi nuklir adalah Lithium dan Hidrogen (terutama Lithium-6, Deuterium, Tritium).

Diary 14 Meeting

Today on english For IT II I learned a lot about United States Census Bureau and the following is a summary of the material I’ve learned : The fact that most Americans live in urban areas does not mean that they are in the middle of a big city. The Census Bureau considers that an area of more than 2500 people as urban areas, and does not consider the boundaries of cities and suburbs. According to the Bureau, the political boundaries are less significant than the social and economic relations and transportation and communication systems thatintegrate locale. The term used by the Bureau for a unified metropolis is MSA, which stands for Metropolitan Statistical Areas.

At this time, the Bureau reported more than 280 MSAs, which together reach 75 percent of the U.S. population. One of the most obvious megapolises including chain of hundreds of cities and suburbs across the state on the East Coast from Massachusetts to Virginia, including Boston, New York, and Washington, DC In the East Corridor, as it is called, a population of 45 million residents are concentrated. Another fast-growing megalopolis is the California coast from San Francisco via Los Angeles to San Diego.

Diary 13 Meeting

Today, on May 14, 2012, I studied English for IT II, in this course I learned about Charles Francis Richter and the following is a summary :

Seismologists have found the two scales of measurement that allows them to describe and record information about the earthquake in quantitative terms. Measurements of the most widely known is the Richter scale, logarithmic numerical

scale was developed and introduced by the American seismologist Charles F. Richter in 1935. The purpose of this scale is to measure the amplitude of the biggest tracks recorded by seismographs standard one hundred kilometers from the epicenter.

Other earthquake-scale assessment, introduced by the Italian seismologist Giuseppe Mercalli, measures the intensity of shaking, using a gradient of 1 to 12. Because shock effects such as fade with distance from the epicenter of the earthquake, the Mercalli ratings depending on where the measurements. Mercalli earthquake of 2 or 3 on the Richter essentially the same as 3 or 4; measuring 11 or 12 on the Mercalli scale can be roughly correlated with the magnitude of 8 or 9 on the Richter scale. It is estimated that almost one million earthquakes occur each year, but some of them so small that they pass undetected. In fact, more than a thousand earthquakes measuring 2 or lower on the Richter scale happen every day.

Diary 12 Meeting

Today on May 7, 2012, in English For IT II I learned about Noise, and the following is a summary : Although noise, generally defined as unwanted sound, is a widely recognized form of pollution, it is very difficult to measure because of the discomfort experienced by different individuals is highly subjective and therefore variable. Exposure to low levels of noise may be a little mimic, whereas exposure to higher levels can actually cause hearing loss. Unlike the eye, which can be covered by the eyelid against strong light, the ear has not closed, and therefore, always open and vulnerable; noise penetrates without protection.

Noise causes hearing effects can not control and where the body never becomes accustomed. Loud voice instinctively danger signal for any organism with the hearing mechanism. Function of the improvement brought about by a rush of adrenaline is released in response to fear, and some of these responses lasted for thirty minutes after the sound has stopped.

Diary 11 Meeting

On April 30, 2012 which falls on Monday, I am studying English For IT II, at its eleventh meeting, I learned about the

American Family and as usual the following is a summary I made :Nuclear family, consisting of mother, father, and their children, may be more ideal than the reality of America America. Recent government statistics census revealed that only about one-third of all American families in accordance with the current traditional mold of the two parents and their children, and another third consists of married couples who either do not have children or do not have still living at home.

There are several reasons for the increasing number of easily identifiable single-parent households. First, the sociological phenomenon of single parent households reflect changing cultural attitudes to divorce and to unmarried mothers. In addition, the number of children born to unmarried women who choose to keep their children and raise them alone has increased dramatically. In addition, because many families live far from relatives, close friends have

 

become a more important part of family life than ever before. Most Americans claim that they have people in their lives that they consider to be a family even though they are not related. Views of families who received only traditional nuclear arrangement not only ignores the reality of modern American family life, but also undervalues family ties made in alternative family arrangements.

 

Diary 10 Meeting

On April 30, 2012 which falls on Monday, I am studying English For IT II, at its eleventh meeting, I learned about the

American Family and as usual the following is a summary I made :Nuclear family, consisting of mother, father, and their children, may be more ideal than the reality of America America. Recent government statistics census revealed that only about one-third of all American families in accordance with the current traditional mold of the two parents and their children, and another third consists of married couples who either do not have children or do not have still living at home.

There are several reasons for the increasing number of easily identifiable single-parent households. First, the sociological phenomenon of single parent households reflect changing cultural attitudes to divorce and to unmarried mothers. In addition, the number of children born to unmarried women who choose to keep their children and raise them alone has increased dramatically. In addition, because many families live far from relatives, close friends have

become a more important part of family life than ever before. Most Americans claim that they have people in their lives that they consider to be a family even though they are not related. Views of families who received only traditional nuclear arrangement not only ignores the reality of modern American family life, but also undervalues family ties made in alternative family arrangements.

Diary 9 Meeting

Today in English For IT II I learned a lot about Geyser and the following is a summary of the material I’ve learned :

A geyser is a result of underground water temperature rose about 1 ° F for every sixty feet below the surface of the Earth, and increasing pressure with depth is very hot in the interior of the Earth to about 290 ° F.
but the geysers, the weight of water near the surface pressure over the geyser reaches higher temperatures than water at the top.

Favorable conditions for the fountain in the area geologically recent volcanic activity, especially in areas of more than average rainfall. For the most part, the geysers in the three regions of the world: New Zealand, Iceland, and Yellowstone National Park area the United States. The world’s most famous geyser is Old Faithful in Yellowstone Park. Old Faithful erupts every hour, up to a height of 125-170 feet,
unlike most geysers, never fails to erupt on schedule even once in eight years of observation.

As the water becomes warmer, lighter and consequently, a sudden rise to the surface and bud out from the surface in the form of steam and hot water. In the end create more explosions. Soon after, the water flows back into the underground reservoir, heating begins, and the process repeated. To function, then, the geyser must have a heat source, a reservoir where water can be stored until the temperature rises to a stable point.

Diary 8 Meeting

We discuss about the midterm question and together with the 50 questions correct than 150 questions,at the class Iam so confused,at the class  we only discuss the type B, which is multiple choice and error analysis, the result of the midterm test is ugly and miss sloria told us to study this matter better in the UAS later, and the last the model test type B was sent in email ilearning, milis sloria@ilearning.

I Hope at UAS i have the big score and My english ipk is great too, so i will study very hard and don’t give up to myself

Diary 7 Meeting

The Father of American Education”,” Horace Mann, was born in Franklin, Massachusetts, in 1796. Mann’s schooling consisted only of brief and erratic periods of eight to ten weeks a year. Mann educated himself by reading ponderous volumes from the Franklin Town Library. This self education,

combined with the fruits of a brief period of study with an intinerant school master, was sufficient to gain him admission to the sophomore class of Brown University in 1816″ (4, Cremin). He went on to study law at Litchfield Law School and finally received admission to the bar in 1823 (15, Filler). In the year 1827 Mann won a seat in the state legislature and in 1833 ran for State Senate and won

Diary 6 Meeting

Written documentation of the history of New York City began with the first European visit to the area by Giovanni da Verrazzano, in command of the French ship, La Dauphine, when he visited the region in 1524. It is believed he sailed in Upper New York Bay where he encountered nativeLenape, returned through The Narrows where he anchored the night of April 17, and then left to continue his voyage. He named the area of present-day New York City Nouvelle-Angoulême (New Angoulême) in honor of Francis I of France, King of France and Count of Angoulême.^[1]

European settlement began on September 3, 1609 when EnglishmanHenry Hudson in the employ of theDutch East India Company sailed the Half Moon through The Narrows into Upper New York Bay. Like Christopher Columbus, Hudson was looking for a westerly passage toAsia. He never found one, but he did make note of the abundant beaver population. Beaver pelts were in fashion in Europe, fueling a lucrative business. Hudson’s report on the regional beaver population served as the impetus for the founding of Dutch trading colonies in the New World, among them New Amsterdam, which would become New York City. The beaver’s importance in New York City history is reflected by its use on the city’s official seal.

The Dutch West Indies Company transported Africa slaves to the post as trading laborers. By the late 17th century, 40 percent of the settlement were African slaves. They helped build the fort and stockade, and some gained freedom under the Dutch. After the English took over the colony and city they called New York, they continued to import slaves from Africa and the Caribbean. In 1703, 42 percent of the New York households had slaves; they served as domestic servants and laborers, but also became involved in skilled artisan trades, shipping and other fields. They were integral to the development of colonial and federal New York. By the time of the Revolution, slaves comprised nearly a quarter of the city’s population; second only to Charleston, South Carolina, New York had the largest number of slaves of any city in the nation.

The area around New York City was the location for multiple battles of the American Revolutionary War, including the largest battle of the war: the Battle of Brooklyn. With victory, the British occupied the city from September 1776 to late 1783. In response to the Crown’s offer of freedom for slaves who left rebel masters, by 1780 the city became crowded with 10,000 blacks, most of whom had escaped slave masters. The British evacuated 3,000 freedmen with their troops in 1783; the Black Loyalists had chosen resettlement in Nova Scotia and other colonies. George Washington was inaugurated as the first President of the United States on April 30, 1789 in front of Federal Hall and the city served as the capital of the United States until 1790. The New York legislature passed a program of gradual emancipation in 1799; finally abolishing all slavery in the state in 1827.

Beginning in the mid-nineteenth century, waves of new immigrants arrived from Europe, dramatically changing the composition of the city and serving as workers in the expanding industries. Modern New York City traces its development to the consolidation of the five boroughs in 1898 and an economic and building boom following the Great Depression and World War II. Throughout its history, New York City has served as a main port of entry for many immigrants, and its cultural and economic influences have made it one of the most important urban areas in the United States, and the world.