Selenates are analogous to sulfates and have similar chemistry. They are highly soluble in aqueous solutions at ambient temperatures.
Unlike sulfate, selenate is a somewhat good oxidizer; it can be reduced to selenite or selenium.
In strongly acidic conditions, the hydrogen selenate ion, HSeO4−, is formed. It corresponds to the selenic acid, H2SeO4, which is a strong acid and can in its concentrated form dissolve gold.
The element selenium exhibits several valence states. Selenate is the least reduced, followed by selenite, and elemental selenium. The valence state is an important factor to the toxicity of selenium. Selenate is the form required by organisms that need selenium as a micronutrient. These organisms have the ability to acquire, metabolize and excrete selenium. The level at which selenium becomes toxic varies from species to species and is related to other environmental factors like pH and alkalinity that influence the concentration of selenite over selenate.
Solid SeO2 is a one-dimensional polymer, the chain consisting of alternating selenium and oxygen atoms. Each Se atom is pyramidal and bears a terminal oxide group. The bridging Se-O bond lengths are 179 pm and the terminal Se-O distance is 162 pm. The relative stereochemistry at Se alternates along the polymer chain (syndiotactic).
In the gas phase selenium dioxide is present as dimers and other oligomeric species, at higher temperatures it is monomeric. The monomeric form adopts a bent structure very similar to that of sulfur dioxide with a bond length of 161 pm. The dimeric form has been isolated in a low temperature argon matrix and vibrational spectra indicate that it has a centrosymmetric chair form. Dissolution of SeO2 in selenium oxydichloride give the trimer [Se(O)O]3.
Monomeric SeO2 is a polar molecule, with the dipole moment of 2.62 D pointed from the midpoint of the two oxygen atoms to the selenium atom.
Search engine optimization (SEO) is the process of affecting the visibility of a website or a web page in a search engine's unpaid results—often referred to as "natural," "organic," or "earned" results. In general, the earlier (or higher ranked on the search results page), and more frequently a site appears in the search results list, the more visitors it will receive from the search engine's users. SEO may target different kinds of search, including image search, local search, video search, academic search, news search and industry-specific vertical search engines.
As an Internet marketing strategy, SEO considers how search engines work, what people search for, the actual search terms or keywords typed into search engines and which search engines are preferred by their targeted audience. Optimizing a website may involve editing its content, HTML and associated coding to both increase its relevance to specific keywords and to remove barriers to the indexing activities of search engines. Promoting a site to increase the number of backlinks, or inbound links, is another SEO tactic. As of May 2015, mobile search has finally surpassed desktop search,Google is developing and pushing mobile search as the future in all of its products and many brands are beginning to take a different approach on their internet strategies
In Team Fortress 2, players join one of two teams comprising nine character classes, battling in a variety of game modes including capture the flag and king of the hill. The development is led by John Cook and Robin Walker, creators of the original Team Fortress. Announced in 1998, the game once had more realistic, militaristic visuals and gameplay, but this changed over the protracted nine-year development. After Valve released no information for six years, Team Fortress 2 regularly featured in Wired News' annual vaporware list among other ignominies. The finished Team Fortress 2 has cartoon-like visuals influenced by the art of J. C. Leyendecker, Dean Cornwell and Norman Rockwell and is powered by Valve's Source engine.
An engineer (American and Canadian), engine driver, train driver, train operator (British and Commonwealth English) is a person who operates a train. The engineer is in charge of and responsible for driving the engine, as well as the mechanical operation of the train, train speed, and all train handling. The use of the term engineer to describe this occupation in North America should not be confused with the usual meanings of engineer.
For many American railroads, the following career progression is typical: assistant conductor (brakeman), conductor and finally engineer. In the US, engineers are required to be certified and re-certified every two to three years. In American English a hostler moves engines around train yards, but does not take them out on the normal tracks.
In India, a driver starts as a diesel assistant or electrical assistant (in case of electric locomotives). They then get promoted on a scale: goods, passenger, Mail/Express and Rajdhani/Shatabdi/Duronto.
In Europe, the engineer degree is ranked at the same academic level as a master's degree, and is often known literally as an "engineer diploma" (abbreviated Dipl.-Ing. or DI). In some countries of Latin America and the United States, the engineer's degree can be studied after the completion of a master's degree and is usually considered higher than the master's degree but below the doctorate in engineering (abbreviated Dr.-Ing.) in Europe. In other countries of Latin America, there is no proper engineer's degree, but the title of Engineer is used for 4 year bachelor's graduates.
Through the Canadian Engineering Accreditation Board (CEAB), Engineers Canada accredits Canadian undergraduate engineering programs that meet the standards of the profession. Graduates of those programs are deemed by the profession to have the required academic qualifications to be licensed as professional engineers in Canada.