Periods, long

The effects of pollution can be direct, such as toxic emissions providing a fatal dose of toxicant to fish, animal life, and even human beings. The effects also can be indirect. Toxic materials which are nonbiodegradable, such as waste from the manufacture of insecticides and pesticides, if released to the environment, are absorbed by bacteria and enter the food chain. These compounds can remain in the environment for long periods of time, slowly being concentrated at each stage in the food chain until ultimately they prove fatal, generally to predators at the top of the food chain such as fish or birds. 

Combustion in an incinerator is the only practical way to deal with many waste streams.This is particularly true of solid and concentrated wastes and toxic wastes such as those containing halogenated hydrocarbons, pesticides, herbicides, etc. Many of the toxic substances encountered resist biological degradation and persist in the natural environment for a long period of time. Unless they are in dilute aqueous solution, the most effective treatment is usually incineration. 

Drill ships are used in deep water and remote areas, and these vessels are equipped with a drilling unit positioned in the middle of the ship. Positioning is achieved dynamically by computer controlled thrusters. The ample storage space allows operation for long periods of time without re-supply. 

Alkanes from CH to C4gFlg2 typically appear in crude oil, and represent up to 20% of the oil by volume. The alkanes are largely chemically inert (hence the name paraffins, meaning little affinity), owing to the fact that the carbon bonds are fully saturated and therefore cannot be broken to form new bonds with other atoms. This probably explains why they remain unchanged over long periods of geological time, despite their exposure to elevated temperatures and pressures. 

If high wellhead pressures are available over long periods, cooling can be achieved by expanding gas through a valve, a process known as Joule Thomson (JT) throttling. The valve is normally used in combination with a liquid gas separator and a heat exchanger, and inhibition measures must be taken to avoid hydrate formation. The whole process is often termed low temperature separation (LTS). 

Electro-magnetic emission in the radiowave range is for long period of time used for water basins diagnostics. 

Adsorbates can physisorb onto a surface into a shallow potential well, typically 0.25 eV or less [25]. In physisorption, or physical adsorption, the electronic structure of the system is barely perturbed by the interaction, and the physisorbed species are held onto a surface by weak van der Waals forces. This attractive force is due to charge fiuctuations in the surface and adsorbed molecules, such as mutually induced dipole moments. Because of the weak nature of this interaction, the equilibrium distance at which physisorbed molecules reside above a surface is relatively large, of the order of 3 A or so. Physisorbed species can be induced to remain adsorbed for a long period of time if the sample temperature is held sufficiently low. Thus, most studies of physisorption are carried out with the sample cooled by liquid nitrogen or helium. 

Intennittency, in tire context of chaotic dynamical systems, is characterized by long periods of nearly periodic or Taminar motion interspersed by chaotic bursts of random duration [28]. Witliin tliis broad phenomenological... 

It remains to investigate the zeros of Cg t) arising from having divided out by. The position and number of these zeros depend only weakly on G, but depends markedly on the fomi that the time-dependent Hamiltonian H(x, () has. It can be shown that (again due to the smallness of ci,C2,...) these zeros are near the real axis. If the Hamiltonian can be represented by a small number of sinusoidal terms, then the number of fundamental roots will be small. However, in the t plane these will recur with a period characteristic of the periodicity of the Hamiltonian. These are relatively long periods compared to the recurrence period of the roots of the previous kind, which is characteristically shorter by a factor of... 

The periodic table also contains horizontal periods of elements, each period beginning with an element with an outermost electron in a previously empty quantum level and ending with a noble gas. Periods 1, 2 and 3 are called short periods, the remaining are long periods Periods 4 and 5 containing a series of transition elements whilst 6 and 7 contain both a transition and a rare earth senes,... 

This reaction proceeds very slowly in absence of light, and aqueous solutions of potassium manganate(VII) are effectively stable for long periods if kept in dark bottles. 

We have derived time-reversible, symplectic, and second-order multiple-time-stepping methods for the finite-dimensional QCMD model. Theoretical results for general symplectic methods imply that the methods conserve energy over exponentially long periods of time up to small fluctuations. Furthermore, in the limit m —> 0, the adiabatic invariants corresponding to the underlying Born-Oppenheimer approximation will be preserved as well. Finally, the phase shift observed for symmetric methods with a single update of the classical momenta p per macro-time-step At should be avoided by... 

The acid chloride is available commercially, but it is more economical to prepare it from the acid as and when required. Furthermore, 3 5-dini-trobenzoyl chloride tends to undergo hydrolysis if kept for long periods, particularly if the stock bottle is frequently opened. The substance may, however, be stored under light petroleum. 

CAUTION. Ethers that have been stored for long periods, particularly in partly-filled bottles, frequently contain small quantities of highly explosive peroxides. The presence of peroxides may be detected either by the per-chromic acid test of qualitative inorganic analysis (addition of an acidified solution of potassium dichromate) or by the liberation of iodine from acidified potassium iodide solution (compare Section 11,47,7). The peroxides are nonvolatile and may accumulate in the flask during the distillation of the ether the residue is explosive and may detonate, when distilled, with sufficient violence to shatter the apparatus and cause serious personal injury. If peroxides are found, they must first be removed by treatment with acidified ferrous sulphate solution (Section 11,47,7) or with sodium sulphite solution or with stannous chloride solution (Section VI, 12). The common extraction solvents diethyl ether and di-tso-propyl ether are particularly prone to the formation of peroxides. 

When semicarbazide Ls heated in the absence of a carbonyl compound for long periods, condensation to blurea, NHjCONHNHCONHj, m.p. 247-250 (decomp.), may result occasionally this substance may be produced in the normal preparation of a semicarbazone that forms slowly. Biurea is sparingly soluble in alcohol and soluble in hot water, whereas semicarbazones with melting points in the same range are insoluble in water this enables it to be readily distinguished from a semicarbazone. 

The 5-nitrosallcylaldehyde reagent is prepared as follows. Add 0-5 g. of 5-nitrosalicylaldehyde (m.p. 124-125°) to 15 ml. of pure triethanolamine and 25 ml. of water shake until dissolved. Then introduce 0-5 g. of crystallised nickel chloride dissolved in a few ml. of water, and dilute to 100 ml. with water. If the triethanolamine contains some ethanolamine (thus causing a precipitate), it may be necessary to add a further 0 - 5 g. of the aldehyde and to filter off the resulting precipitate. The reagent is stable for long periods. 

The carbon disulphide reagent is prepared by adding to a solution of 0-5 g. of crystallised nickel chloride in 100 ml. of water enough carbon disulphide so that after shaking a globule of carbon disulphide is left at the bottom of the bottle. The reagent is stable for long periods in a well-stoppered bottle. If all the carbon disulphide evaporates, more must be added. 

An ethereal solution of diazomethane is usually prepared immediately before it is required for reaction. Two intermediates may be used for this purpose, viz., nitrosomethylurea and p-tolylsulphonylmethylnitrosamide a number of methods are available for obtaining the former the latter is prepared from methylamine and p-toluenesulphonyl chloride. Nitrosomethylurea is not very stable at room temperatures and must be kept at 0° on the other hand p-tolylsulphonylmethylnitrosamide is a stable solid, which can be kept for long periods at room temperature in a dark bottle. 

The preparation can be kept for long periods in a refrigerator, preferably in smooth, brown, alkali-free bottles it should not be kept above 20° for more than a few hours at 30°, it may undergo sudden decomposition and a serious explosion may result. 

The crude sulphonyl chloride, even if dry, cannot bo kept without considerable decomposition. It may be purified by dissolving it in a mixture of equal volumes of benzene and acetone, separating the water, and allowing the solvent to evaporate until crystallisation occurs the recrystallised substance may be preserved for long periods. 

The control of carbon dioxide emission from burning fossil fuels in power plants or other industries has been suggested as being possible with different methods, of which sequestration (i.e., collecting CO2 and injecting it to the depth of the seas) has been much talked about recently. Besides of the obvious cost and technical difficulties, this would only store, not dispose of, CO2 (although natural processes in the seas eventually can form carbonates, albeit only over very long periods of time). 

An even less complicated reaction vessel may be used for reactions in liquid amtnonia which produce only a small amount of "heat" over a relatively long period and which proceed under homogeneous conditions. The conversion can then be performed in a one-necked flask with a stopper + gas outlet or small hole. 

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