Niobium (Columbium) Chemical and Physical Properties

Niobium (Columbium) Chemical and Physical Properties Niobium, like tantalum, can act as an electrolytic valve allowing alternating current to pass in only one direction through an electrolytic cell. Niobium is used in arc-welding rods for stabilized  grades of stainless steel. It is also used in advanced airframe  systems. Superconductive magnets are made with Nb-Zr wire, which retains superconductivity in strong magnetic fields. Niobium is used in lamp filaments and to make jewelry. It is capable of being colored by an electrolytic process. Niobium (Columbium)  Basic Facts Atomic Number: 41Symbol: Nb (Cb)Atomic Weight: 92.90638Discovery: Charles Hatchet 1801 (England)Electron Configuration: [Kr] 5s1 4d4 Word Origin:  Greek mythology: Niobe, daughter of Tantalus, as niobium is often associated with tantalum. Formerly known as Columbium, from Columbia, America, the original source of niobium ore. Many metallurgists, metal societies, and commercial producers still use the name Columbium. Isotopes: 18 isotopes of niobium are known. Properties: Platinum-white with a bright metallic luster, although niobium takes on a bluish cast when exposed to air at room temperatures for a long time. Niobium is ductile, malleable, and highly resistant to corrosion. Niobium does not naturally occur in the free state; it is usually found with tantalum. Element Classification: Transition Metal Niobium (Columbium) Physical Data Density (g/cc): 8.57Melting Point (K): 2741Boiling Point (K): 5015Appearance: shiny white, soft, ductile metalAtomic Radius (pm): 146Atomic Volume (cc/mol): 10.8Covalent Radius (pm): 134Ionic Radius: 69 (5e)Specific Heat (20 °C J/g mol): 0.268Fusion Heat (kJ/mol): 26.8Evaporation Heat (kJ/mol): 680Debye Temperature (K): 275.00Pauling Negativity Number: 1.6First Ionizing Energy (kJ/mol): 663.6Oxidation States: 5, 3Lattice Structure: Body-Centered CubicLattice Constant (Ã…): 3.300 Sources Los Alamos National Laboratory (2001)Crescent Chemical Company (2001)Langes Handbook of Chemistry (1952)CRC Handbook of Chemistry Physics (18th Ed.)

Content Quality and Quantity Are the Cause of Wikipedias Woes

Content Quality and Quantity Are the Cause of Wikipedias Woes Content Quality and Quantity Are the Cause of Wikipedia’s Woes Content Quality and Quantity Are the Cause of Wikipedia’s Woes By Mark Nichol Recent coverage of Wikipedia has pointed out that the collaborative online encyclopedia is in trouble. What’s up? It’s all about production. When Wikipedia was launched in 2001, it attracted many people who found the idea of a user-generated Web resource akin to The Encyclopedia Britannica highly appealing. Since then, multitudes of people have contributed to more than 19 million articles in nearly 300 languages, including almost 4 million items in English. And many more people have taken it upon themselves to continuously refine Wikipedia. That’s one of its greatest strengths: Unlike print encyclopedias, which must wait until the release of a new edition to offer new entries and updates to existing ones, Wikipedia’s massive trove of information is being increased and improved constantly. But as Wikipedia founder Jimmy Wales recently admitted, the pace of progress is slowing. The problem, it seems, is that many contributors are timing out. Wikipedia, operated by the not-for-profit Wikimedia Foundation, is a volunteer enterprise. Writers and editors are not paid for their time. And now, ten years after Wikipedia’s launch, many of those contributors have moved on with their lives. (Another reason many Wikipedia writers have given for bailing out is that some of the site’s volunteer editors, displaying the all-too-common combination of ignorance and arrogance, clumsily compromise the quality of their work.) An additional challenge is that the longtime contributors who remain, and the newcomers who have logged on more recently, are running out of things to write about. Some late-nineteenth-century scientists have earned everlasting opprobrium for their unimaginative declarations that thanks to their manifold discoveries and those of their contemporaries, no new science of any significance would be done in the future. Just as we’ve learned a thing or two about the universe since the late 1800s, however, there will always be new material for Wikipedia, but the momentum is waning, and the number of contributors is declining. Wikipedia has its weaknesses: Both because of and despite its open collaborative nature, factual errors occur (though they’re often caught quickly) and opinions intrude (again, usually not for long). And it doesn’t take too much time on the site to determine that the writing quality varies tremendously. Though Wikipedia claims that studies show its accuracy to be comparable to that of venerable print resources like The Encyclopedia Britannica, it cannot deny that the overall writing quality is much inferior. It’s still a brilliant idea triumphantly realized, and I resort to it often in my work, but it’s something else as well, something that earns it a mention on this Web site: It’s an object lesson in how not to run an editorial enterprise. Call me old-fashioned, but I’d have a great deal more respect for Wikipedia if it rested securely on the foundation of professional writers and editors who are subject-matter experts (or at least highly skilled generalist writers whose expert editors catch any problems with the accuracy of the content). That was the idea behind its predecessor, the professionally developed free encyclopedia Nupedia, of which Wikipedia was originally merely an offshoot. Why has hardly anyone heard of Nupedia? Because it tanked. Why? As the result of a rigorous review process that, partly because only the editor in chief, Larry Sanger, was salaried, proceeded at a glacial pace. Good writing and editing takes time and effort and expense. Great editorial work requires even more expenditure. Nupedia died, and Wikipedia lives, but even many of those who champion the latter acknowledge that its value is as a starting point for locating authoritative information as a means to an end, rather than an end in and of itself. If you want high-quality content well written, impartial, and authoritative you almost invariably have to pay for it. As Wikipedia has learned, there’s no such thing as a free launch. Want to improve your English in five minutes a day? Get a subscription and start receiving our writing tips and exercises daily! Keep learning! Browse the General category, check our popular posts, or choose a related post below:How Many Tenses in English?"Gratitude" or "Gratefulness"?1,462 Basic Plot Types

Language learning assignment Essay Example | Topics and Well Written Essays - 3000 words

Language learning assignment - Essay Example Moreover, it is a reservoir of knowledge of various disciplines like communications, science, business, aviation, entertainment, and diplomacy and also on the Internet. Most of the developments in specialised fields in the developed countries require the usage of English. The advent of Internet and information technology has further emphasised the importance of English as an international language. In this globalised era, the progress and development of a country, to a large extent, is associated with the usage of the English language. After the Second World War, British idealism spread in many parts of the globe and with the United Kingdom becoming highly developed, the language spoken by most European countries, i.e., English became very popular. Thus, over a period of time English has developed into a prominent language. Because of these reasons, the teaching of English, especially in non-English speaking countries has assumed special significance. With the expansion of commerce a nd industry, and the advances in technology, geographical distance has become irrelevant and the world has shrunk into a global village. With the opening up of bigger markets, many new job opportunities became available for aspirants in various fields all over the world. So there is such an unprecedented movement of skilled labourers across the globe and most of them seek Europe and USA as their hopeful destinations. The primary requisite for employment is a working knowledge of English. The requirement and proficiency will vary according to the nature of the job. The burgeoning job opportunities in various fields necessitated the aspirants to master the English language. In the filed of education also English is accepted as the most preferred mediums of instruction and interaction between teacher and pupils. Therefore, proficiency in English language has become a primary necessity. Hence to measure the proficiency of language called for certain criteria. Because of these