Other Discharges

It is often important to quantify the contamination of pore fluid in the unsaturated soil 2one, where monitoring wells are ineffective. In this region, suction cup lysimeters are useful (7). These samplers consist of a porous cup, typically ceramic, having two access tubes which are usually Teflon. One access tube provides a pressure-vacuum, the other discharges the sampled fluid to the surface. The porous cup, typically between 2 and 5 cm in diameter, is attached to a PVC sample accumulation chamber. 

Other Discharge Sources Including Process Water Treatment, Air Pollution Control Systems and Compressor Blowdown... 

This would be induced or caused by operation, if the plant operators strangle valves to control production tlow. Any other discharge flow restriction (clogged filter, pipe obstruction, or tin-calibrated automatic valve) would produce the same evidence. Talk with the plant engineer about this situation and show him the evidence on the pump. 

Besides the conventional Grimm-type dc source, which has dominated the GD-OES scene for approximately 30 years, other discharge sources are well known. Among those are various boosted sources which use either an additional electrode to achieve a secondary discharge, or a magnetic field or microwave power to enhance the efficiency of excitation, and thus analytical capability none of these sources has, however, yet been applied to surface or depth-profile analysis. 

FIG. 17. (a) The relative pressures (i.e.. the ratio of the partial pressure to the total pressure) of Ht. SiHa, and SiiHg, and (b) the deposition rate, as a function of total pressure at an RF frequency of 50 MHz and a plasma power of 5 W. Other discharge settings are given in Table IV. Modeling results are in dotted lines and open symbols, experimental data in solid lines and filled symbols. Note the sudden increase at 30 Pa. i.e.. the transition from the a- to the / -regime. (Compiled from G. J. Nienhuis, Ph.D. Thesis. Universiteit Utrecht. Utrecht, the Netherlands. 1998.)... 

Corona discharge is the simplest type of plasma generator. A feature of the corona discharge, which differentiates it from the other discharges, is that no dielectric is involved. Instead, an electron avalanche is initiated from a sharp metallic surface where the radius of curvature is small. The electric field has to be pulsed in order to prevent the plasma from going into the thermal mode and forming an arc. The electric field in corona reactors is about 50 kV/cm. 

Equation 7-20 assumes a capacitance-type discharge (that is, a spark) however, capacitance and voltage are not defined in nonconductive systems. Therefore Equation 7-20 is valid only for capacitive sparks, but it is used qualitatively for the other discharges. 

For volume production of an aerosol fog of small particle size, on a large scale (suited to indoor use), the thermal aerosol fog generators appear to be very efficient. The Science Service experiments were mostly with this type. Two principal varieties have been developed. One discharges the insecticide solution or suspension as a relatively coarse spray into a jet of superheated steam delivered by a flash boiler of the tubular coil t3rpe. The other discharges that insecticide solution or suspension as a relatively coarse spray into a blast of hot gas emerging from a combustion chamber. The temperature is regulated by the controlled admixture of cold air. 

The presence of other discharge sources can influence the interpretation of the hazard estimate of both the ZPE and LTF schemes. These discharge sources could be either point (e.g., treated municipal sewage discharge) or non-point (e.g., bark or chip pile runoff), entering the watershed up-stream or within the immediate nearfield zone that receives the industrial effluent. 

Sublethal toxicity tests that are relatively less sensitive can reduce the usefulness of both ZPE and LTF. In addition, confounding factors such as the presence of other discharge sources can complicate the interpretation of both hazard assessment schemes. 

Although, as was discussed above, plasma and other discharges are usually discussed in the context of gas-phase processes, electrical discharges are also quite well studied in liquids. For example, liquid-phase discharge reactors have recently been applied in drinking water and... 

Applied water research is nearly always conducted with a restricted budget. Traditionally the larger sums go to the construction of weirs and other discharge measuring devices in surface water studies and the drilling of new wells in groundwater studies. Little money is allocated to hydrochemical investigations. The ratio of outcome to cost is, however, in many cases in favor of hydrochemical studies. 

In the absence of a firm theoretical basis to describe the dependence of the ELM energy loss on pedestal plasma parameters and on other discharge characteristics, several empirical scalings with a physics basis, have been derived in order to extrapolate the ELM energy losses in present experiments to next step devices, such as ITER. 

The data in Tables IV and V show that P/p and rj increase rapidly as X/p is increased, but these increases are also associated with a progressive decrease in j. The mechanism envisaged involves two simultaneous processes, for each of which P/p may be expected to conform with Relation 6 and thus to be independent of j. Consequently an increase of Y with X/p, for which there is ample independent evidence for other discharges, provides a qualitative explanation of the trend of the observed values of P/p and 7j with X/p. But as there are no data relating to a range of j when X/p is constant, no conclusion can be drawn as to whether the experimental data conform with Relation 6, or with Relations 7 or 8 which are characteristic of a mechanism different from that envisaged. 

The discharge mode of Ni-Cd batteries is dependent on their applications. The most common one is the constant-current discharge, in which the current can be changed from very low (e.g., in the case of button-batteries) to very large (e.g., for batteries for wireless tools). There are also other discharge modes, such as constant-resistance discharge, content-power discharge, etc. 

---