Friday, December 27, 2019

Borons Chemical and Physical Properties

Atomic number: 5Symbol: BAtomic weight: 10.811Electron configuration: [He]2s22p1Word origin: Arabic Buraq; Persian Burah. These are the Arabic and Persian words for borax.Isotopes: Natural boron is 19.78% boron-10 and 80.22% boron-11. B-10 and B-11 are the two stable isotopes of boron. Boron has a total of 11 known isotopes ranging from B-7 to B-17. Properties The melting point of boron is 2079Â °C, its boiling/sublimation point is at 2550Â °C, the specific gravity of crystalline boron is 2.34, the specific gravity of the amorphous form is 2.37, and its valence is 3. Boron has interesting optical properties. The boron mineral ulexite exhibits natural fiberoptic properties. Elemental boron transmits portions of infrared light. At room temperature, it is a poor electrical conductor, but it is a good conductor at high temperatures. Boron is capable of forming stable covalently bonded molecular networks. Boron filaments have high strength, yet are lightweight. The energy band gap of elemental boron is 1.50 to 1.56 eV, which is higher than that of silicon or germanium. Although elemental boron is not considered to be a poison, assimilation of boron compounds has a cumulative toxic effect. Uses Boron compounds are being evaluated for treating arthritis. Boron compounds are used to produce borosilicate glass. Boron nitride is extremely hard, behaves as an electrical insulator, yet conducts heat, and has lubricating properties similar to graphite. Amorphous boron provides a green color in pyrotechnic devices. Boron compounds, such as borax and boric acid, have many uses. Boron-10 is used as a control for nuclear reactors, to detect neutrons, and as a shield for nuclear radiation. Sources Boron is not found free in nature, although boron compounds have been known for thousands of years. Boron occurs as borates in borax and colemanite and as orthoboric acid in certain volcanic spring waters. The primary source of boron is the mineral rasorite, also called kernite, which is found in Californias Mojave Desert. Borax deposits are also found in Turkey. High-purity crystalline boron may be obtained by vapor phase reduction of boron trichloride or boron tribromide with hydrogen on electrically heated filaments. Boron trioxide may be heated with magnesium powder to obtain impure or amorphous boron, which is a brownish-black powder. Boron is available commercially at purities of 99.9999%. Quick Facts Element Classification: SemimetalDiscoverer: Sir H. Davy, J.L. Gay-Lussac, L.J. ThenardDiscovery date: 1808 (England/France)Density (g/cc): 2.34Appearance: Crystalline boron is hard, brittle, lustrous black semimetal. Amorphous boron is a brown powder.Boiling point: 4000 Â °CMelting point: 2075 Â °CAtomic radius (pm): 98Atomic volume (cc/mol): 4.6Covalent radius (pm): 82Ionic radius: 23 (3e)Specific heat (20Â °C J/g mol): 1.025Fusion heat (kJ/mol): 23.60Evaporation heat (kJ/mol): 504.5Debye temperature (K): 1250.00Pauling negativity number: 2.04First ionizing energy (kJ/mol): 800.2Oxidation states: 3Lattice structure: TetragonalLattice constant (Ã…): 8.730Lattice C/A ratio: 0.576CAS number: 7440-42-8 Trivia Boron has the highest boiling point of the semimetalsBoron has the highest melting point of the semimetalsBoron is added to glass to increase its resistance to heat shock. Most chemistry glassware is made from borosilicate glassThe isotope B-10 is a neutron absorber and used in control rods and emergency shutdown systems of nuclear generatorsThe countries Turkey and the United States have the largest reserves of boronBoron is used as a dopant in semiconductor production to make p-type semiconductorsBoron is a component of strong neodymium magnets (Nd2Fe14B magnets)Boron burns bright green in a flame test References Los Alamos National Laboratory (2001)Crescent Chemical Company (2001)Langes Handbook of Chemistry (1952)International Atomic Energy Agency ENSDF database (Oct 2010)

Thursday, December 19, 2019

1984 And Beloved Essay - 1403 Words

Sex and love are furtively denied in George Orwell’s 1984 and Toni Morrison’s Beloved by an oppressive totalitarian regime and white slave owners respectively. Love is entirely eradicated to subdue and control the oppressed, but the manipulation of sexuality diverges in the two texts. In Beloved, sex is contorted into violence by the slave owners, whereas it is completely depersonalized in 1984 until repulsive and criminalized. It is therefore through the reclamation of the sexual act that personal liberation occurs. As such, Winston and Sethe do not truly, romantically love Julia and Paul D respectively, but rather use them as vehicles for emancipation from their oppressive realities. It does not matter that it was Julia and Paul D who†¦show more content†¦Sex is universally used, then, to control the black characters and force them to submit. Although the sexual instinct is severely depersonalized in both texts, depersonalization to the point of repulsion via indoctrination is the primary mode d’emploi in 1984, whereas sex has been manipulated by the slave owner into a violent act in Beloved. Sex becomes for members of the Party a task to be completed and ultimately a symbol of loyalty. Katharine, Winston’s estranged wife, is described as being entirely disgusted by sex. Winston reflects that â€Å"to embrace her was like embracing a jointed wooden image†¦ even when she was clasping him against her†¦ she was simultaneously pushing him away with all her strength† (Orwell 66). Yet his wife had still furtively insisted that they must copulate, to the point that she â€Å"used to remind him of it in the morning, as something which had to be done that evening and which must not be forgotten† (66-7). It is their solemn duty to the Party to produce a child, ergo, more Party members. Similarly, all marriages in Oceania must be approved by a committee, who immediately denies the request if any real affection is suggested between the potential spouses. By repressing desire, the Party engineers sexuality into â€Å"hysteria†¦ desirable because it could be transformed into war fever and leader worship† (Orwell 132-3). Julia similarly speculates that one reasonShow MoreRelatedThe Sun Parlor, By Dorothy West1739 Words   |  7 Pagessun parlor, the worse the correlation between the positive feelings and the gleaming room became. Once the narrator’s aunt had died, spending some of her last days in that beloved room, this precious sun parlor, suddenly wasn’t so precious anymore. In fact, no one really wanted to spend time in it anymore. The precious beloved sun parlor suddenly became a place associated with depression, and sadness, all in a matter of moments. 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Wednesday, December 11, 2019

Invasive Species - Causes and Effects free essay sample

From Giant Hogweed to feral cats Invasive species need to be stopped. Defining the Impact/Activity: Invasive species are species that have been introduced to an ecosystem that affect the habitats and bioregions they invade economically, ecologically, socially, and culturally in a negative manner. This paper will describe the intentional and non-intentional causes, ecological, social, cultural, and economic impacts, the solutions, and the ways to prevent invasive species. Causes- Unintentional: Many invasive species were introduced into other ecosystems when the industrial and human transportation industries took off. Many invasive species were introduced through trading, travel and tourism, transport, release of ballast waters from ships, escape from fish farms, openings of canals and waterways, use of live bait, escape from aquariums or water gardens, escape from live food fish trade, recreational boating and movement of equipment and gear, gardening, seed mixtures, escaped pets, and fire wood. Many present day invasive species were introduced through human imprudence and negligence, like the spiny water flea, big head, silver, and black carp, sea lamprey, round goby, fanwort, bass, pike, and zebra mussels. However, many introductions of invasive species were intentional. Causes- Intentional: Although most invasive species were unintentionally brought into an ecosystem, many were 100% intentional, granting the consequences were unknown. For example, the Giant Hogweed was introduced into Canada from Asia because it was considered decorative. However, Giant Hogweed has a watery sap that is like acid to human skin and if it gets into the eyes can cause permanent or temporary blindness. Other invasive species are the dandelion, purple loosestrife, and English ivy. Some species are introduced for ornamental properties, economic gain, cultural beliefs, improving environmental problems, making an area feel more like another, habitat restoration activities, authorized fish stocking, biological control of pests, and releasing pets that someone can’t or won’t look after. (Boa constrictors, feral cats, feral dogs) Impacts- Ecological: Invasive species have caused the extinction and endangerment of hundreds of native species; they cause irreversible changes to habitats, kill and crowd out other species through predation, parasitism, disease, and competition. They also alter ecological processes such as water, nutrient, and energy cycles. They can also breed with native species to cause hybrid species. They can bring new diseases that native species can’t fight. The effects are â€Å"immense, insidious, and usually irreversible. † (https://wwf. panda. org/about_our_earth/species/problems/invasive_species/) Impacts- Social: Along with dangers to the environment invasive species can be very disruptive of our social and recreational areas. Invasive species like the snakehead fish, boa constrictor, red fire ants, and the African Rock Python (a new snake found in the Florida everglades and expected to become invasive) all are potentially dangerous to humans. Aquatic invaders can make recreation like swimming and boating difficult, and sometimes camping, hiking, and biking can be made impossible by alien species. They can also invade in parks and public places and decrease public appeal. Impacts- Economical: Along with the social and Ecological impacts, it costs a lot of money in damages, preventions, and solutions relating to invasive species. The damages due to invasive species costs the world $1. 7 trillion every year, in the Great Lakes Zebra mussels cost $3-$7. 5 billion in damages every year, and cost forest and agriculture industries in Canada $7. 3 million, they also decrease property value and reduce the value of commercial and recreational fishing. Impacts- Cultural: An affect that is not widely recognized is cultural impacts. Many aboriginal tribes lose the medicinal plants and cultural materials needed in cultural practices. Many invasive species alter culturally significant sites and take away food sources, some native species vital to cultural practices are killed with non-target pesticide contamination. Solutions- Prevention: There is no simple solution to invasive species; one of the most common characteristics of invasive species is their fast growth, rapid reproduction, high dispersal ability, and high adaptability, this makes many invasive species very hard to eradicate. Because of this the main solution for invasive species is preventing their spread. One of the best ways to prevent the introduction of indigenous species is to be cautious of the pathways. For example, people should clean their boats thoroughly before moving it to different bodies of water. Dredging, dams, traps, electrical fields, mechanical barriers, trenching, and sticky bands are some other good ways to prevent there spread. Solutions: Because of many invasive species growth, reproduction, dispersal, and adaptability rates getting rid of them can be very difficult. Some methods people have used are; mechanical harvesting, hand-pulling plants, cutting and destroying infested material, poison, use of a living organisms, and pesticides. However, with many of these species leaving one pregnant female of one solitary plant can lead to a re-infestation. Removing invasive species is easier said then done. Conclusion: In conclusion, invasive species are a very negative affect on the biodiversity of our ecosystems and need to be exterminated.

Wednesday, December 4, 2019

The Sun Also Rises Essay Paper Example For Students

The Sun Also Rises Essay Paper Julys People is a story of a white family who experience life as black people would in South Africa at the time. They leave their home and their jobs in the United States and follow their servant, July, to live in an African tribe. The whole time that they are living in Africa they depend on July for survival yet they still treat him as a servant. July wishes that he would be treated more as an equal but besides that he does not mind being their servant as long as he gets paid. The reversal of roles, in this book, does not really change people. It is as though they know where they stand with each other and that could never change. The Smales would always be above July, who would always be destined to be their servant no matter how much their lives depended on him. We will write a custom essay on The Sun Also Rises Paper specifically for you for only $16.38 $13.9/page Order now In the United States the Smales were probably a little more well off than an average family. The father worked as an architect and made good money, that is evident because they can afford a servant. They decide to leave their home and to move to a new and unfamiliar place. July leads them to his tribe in Africa. The change occurs right there, to the Smales United States is home but to July it is a foreign place, whereas Africa is where July feels at home and the Smales feel like they are on another planet. Being strangers to this new place Smales depend on July for survival. Their inability to Goldenberg 2communicate with the natives and the fact that they are the only whites in a tribe complicates things. They depend on July to get tools, find shelter, and get food among other things. At the same time they dont trust him. They are always suspecting that he is stealing from them, they get upset when he takes the truck with out their permission, they feel like he is trying to cheat th em in some way. The Smales were never thought of as being part of the tribe, they stood out, not only because they were white but also because they came from a different culture. July remains their servant through out the whole book. Neither of them, July nor the Smales, attempted becoming good friends and working together through the hardships of war. July demands money for everything he does and the Smales expect for him to take care of things. In this book the author, Nadine Gordimer, is showing us how even when you put different people together, and force them to live in the same conditions, that wont necessarily make these people equal. How these white people came into their village and thought of them as servants. But the other half of the problem is that these natives allowed for such treatment by excepting money for their deeds. I think this symbolizes the situation in South Africa at the time, by showing how easily these natives could be pushed around. The Smales represent the whites that moved to Africa and enslaved blacks. And July represents the blacks that allowed the whites to take advantage of them in their own town.