Main causes

The hydrogencarbonate ion, produced in nature by this reaction, is one of the main causes of temporary hardness in water. Carbon dioxide is fairly soluble in water, 1 cm dissolving 1.7 cm of the gas at stp. The variation of solubility with pressure does not obey Henry s law, since the reaction... 

Comphcated theoretical calculations, based on filled shell (magic number) and other nuclear stabiUty considerations, have led to extrapolations to the far transuranium region (2,26,27). These suggest the existence of closed nucleon shells at Z = 114 (proton number) and N = 184 (neutron number) that exhibit great resistance to decay by spontaneous fission, the main cause of instabiUty for the heaviest elements. Eadier considerations had suggested a closed shell at Z = 126, by analogy to the known shell at = 126, but this is not now considered to be important. 

The main cause of anode wear is electrochemical oxidation or sulfur attack of anodic surfaces. As copper is not sufficiently resistant to this type of attack, thin caps of oxidation and sulfur-resistant material, such as platinum, are bra2ed to the surface, as shown in Eigure 15a. The thick platinum reinforcement at the upstream corner protects against excessive erosion where Hall effect-induced current concentrations occur, and the interelectrode cap protects the upstream edge from anodic corrosion caused by interelectrode current leakage. The tungsten undedayment protects the copper substrate in case the platinum cladding fails. 

Decomposition Hazards. The main causes of unintended decompositions of organic peroxides are heat energy from heating sources and mechanical shock, eg, impact or friction. In addition, certain contaminants, ie, metal salts, amines, acids, and bases, initiate or accelerate organic peroxide decompositions at temperatures at which the peroxide is normally stable. These reactions also Hberate heat, thus further accelerating the decomposition. Commercial products often contain diluents that desensitize neat peroxides to these hazards. Commercial organic peroxide decompositions are low order deflagrations rather than detonations (279). 

Carbonyl sulfide is overall the most abundant sulfur-beating compound ia the earth s atmosphere 430—570 parts per trillion (10 ), although it is exceeded by H2S and SO2 ia some iadustrial urban atmospheres (27). Carbonyl sulfide is beheved to origiaate from microbes, volcanoes, and the burning of vegetation, as well as from iadustrial processes. It may be the main cause of atmospheric sulfur corrosion (28). 

Thermal conductivity and thermal diffusivity are also dependent on pore and crack stmcture. Thermal conductivities for coals of different ranks at room temperature are in the range of 0.23- 0.35 W/(m-K). The range includes the spread owing to crack variations and thermal diffusivities of (1-2) X 10 cm /s. At 800°C these ranges increase to 1-2 W/(m-K) and (1-5) x 10 cm /s, respectively. The increase is mainly caused by radiation across pores and cracks. 

A low p.f. means a higher load current than necessary and accompanying higher line losses. Inductive loads are the main cause of a low p.f., with induction motors the major contributors. Under operating conditions a motor may often be operating underloaded due to one or more of the following reasons ... 

Sections of the borehole casing threatened by corrosion can be located with the help of the profile measurement technique described in Section 18.3.1. In general, the profile measurement cannot identify which factors are the main cause of corrosion danger. 

Computer simulation is an experimental science to the extent that calculated dynamic properties are subject to systematic and statistical errors. Sources of systematic error consist of size dependence, poor equilibration, non-bond interaction cutoff, etc. These should, of course, be estimated and eliminated where possible. It is also essential to obtain an estimate of the statistical significance of the results. Simulation averages are taken over runs of finite length, and this is the main cause of statistical imprecision in the mean values so obtained. 

The main causes of failure in gear couplings are wear or surface fatigue caused by lack of lubricant, incorrect lubrication, or excessive surface stresses. Component fracture caused by overload or fatigue is generally of secondary importance. 

For many years the plate-and-frame systems have used flush plates with separate frames to contain the cake. These filter presses had many sealing surfaces which were the main cause for leakages. As a result recessed plates were introduced in order to cut the number of surfaces in half and reduced the problem of drippings. The development of recessed plates has gone hand in hand with advances in cloth technology which enabled three-dimensional stretching as opposed to simple plate-and-frame where the cloth remains in one plain. Present recess depths are 16, 20 and 25 mm so the corresponding cake thicknesses are 32, 40 and 50 mm at... 

Occupational and environmental exposure to chemicals can take place both indoors and outdoors. Occupational exposure is caused by the chemicals that are used and produced indoors in industrial plants, whereas nonoccupa-tional (and occupational nonindustrial) indoor exposure is mainly caused by products. Toluene in printing plants and styrene in the reinforced plastic industry are typical examples of the two types of industrial occupational exposures. Products containing styrene polymers may release the styrene monomer into indoor air in the nonindustrial environment for a long time. Formaldehyde is another typical indoor pollutant. The source of formaldehyde is the resins used in the production process. During accidents, occupational and environmental exposures may occur simultaneously. Years ago, dioxin was formed as a byproduct of production of phenoxy acid herbicides. An explosion in a factory in... 

Molecular sieve beds do not suffer any chemical degradation and can be regenerated indefinitely. Care should be taken to minimize mechanical damage to the solid crystals as this may decrease the bed s effectivenes . The main causes of mechanical damage are sudden pressure and/or temperature changes when switching from absorption to regeneration cycles. 

The main cause of pump failure, often accompanied by a leak, are ... 

Here Tq are coordinates in a reference volume Vq and r = potential energy of Ar crystals has been computed [288] as well as lattice constants, thermal expansion coefficients, and isotope effects in other Lennard-Jones solids. In Fig. 4 we show the kinetic and potential energy of an Ar crystal in the canonical ensemble versus temperature for different values of P we note that in the classical hmit (P = 1) the low temperature specific heat does not decrease to zero however, with increasing P values the quantum limit is approached. In Fig. 5 the isotope effect on the lattice constant (at / = 0) in a Lennard-Jones system with parameters suitable for Ne atoms is presented, and a comparison with experimental data is made. Please note that in a classical system no isotope effect can be observed, x "" and the deviations between simulations and experiments are mainly caused by non-optimized potential parameters. 

The TNT equivalence of the blast was estimated to be 20-60 tons (Davenport, 1983). The area of total destruction was 430,000 ft (40,000 m ) and the area of total destruction plus severe damage was 3,200,000 ft (300,000 m ) (Figures 2.7-2.9). The main cause of the explosion was the turbulence generated by the release itself. The release did, however, occur in a very congested area. 

This equation gives higher transmissivity values than those calculated with methods described earlier. Presumably, Lihou and Maund s transmissivity is to be used for conditions of low relative humidity, in which dust particles (haze) are the main cause of attenuation. A conservative approach is to assume = 1. 

A particularly important property of ozone is its strong absorption in the ultraviolet region of the spectrum between 220-290 nm ( max255.3nm) this protects the surface of the earth and its inhabitants from the intense ultraviolet radiation of the sun. Indeed, it is this absorption of energy, and the consequent rise in temperature, which is the main cause for the existence of the stratosphere in the first place. 

United States had at least one PC or computer terminal. The more PCs and computer terminals used m a given building, the greater the impact on the building s energy consumption. The proliferation of personal computers, printers, copiers, and other types of plug loads is the main cause of the rise in energy intensity in recent years. 

Twist-offs, a rupture of the drillstring, mainly occur at tool joints or connections between drillpipe and drill collar. The main causes for twist-offs are... 

Abnormal Formation Pressures Origin. Four main causes are attributed to abnormal formation pressures compaction effects, diagenetic effects, differential density effects and fluid migration. 

The design of the ductwork must ensure that the plant is both effective and efficient. Sharp bends and abmpt entries of branches into mains cause unnecessary pressure losses. Incorrectly sized ducts result in high pressure losses or blockages due to fallout from velocities being too low. 

Often, the main cause of catalyst losses is a change in the mechanical condition of the unit. Examples are ... 

Some of the main causes of loss of pressure differential across the slide valves are as follows ... 

Other gases which are occasionally present usually arise from pollution. Ammonia, which in various forms may be present in waste waters, attacks copper and copper alloys its presence in estuarine waters is one of the main causes of condenser-tube corrosion. 

In more recent work embrittlement in water vapour-saturated air and in various aqueous solutions has been systematically examined together with the influence of strain rate, alloy composition and loading mode, all in conjunction with various metallographic techniques. The general conclusion is that stress-corrosion crack propagation in aluminium alloys under open circuit conditions is mainly caused by hydrogen embrittlement, but that there is a component of the fracture process that is caused by dissolution. The relative importance of these two processes may well vary between alloys of different composition or even between specimens of an alloy that have been heat treated differently. 

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