Secondary discharge

Closure plate (optional) Secondary discharge (where needed or desired)... 

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. 

Is a self-contained, closed-loop system that produces no secondary discharges or air emissions. 

The detector of choice for the efficient detection of 14-KeV y-rays is the gas proportional counter with a (mostly) krypton filling. (Methane, which we use, or carbon dioxide are typically added in a concentration of ca. 10% for quenching secondary discharges.)... 

Several different approaches have been used to minimize formation of a secondary discharge, which results from parasitic capacitance between the plasma and the load coil. A balanced load coil can be used where the two ends of a single load coil are driven by rf signals of opposite phase but nearly equal amplitude [9] (as is done on Perkin Elmer/Sciex instruments, called PlasmaLok). Then the center of the load coil is at 0 V. In some cases the center of the load coil can be directly connected to ground or to the sampling plate of the mass spectrometer. Alternatively, two separate load coils can be interlaced to form a balanced rf drive system (as is done on Varian instruments). 

In some cases, a secondary relief device can discharge into a low-pressure system (e.g., fuel gas). This minimizes product loss. An automatic pressure-controlled vent is most suitable for this purpose. This technique can only be applied when the secondary discharge rate is small enough not to upset the low-pressure system. The secondary relief device must be carefully sized accordingly. 

Recondition Secondary discharge, which drains the battery of its remaining energy, during which the crystalline formation (memory) is dissolved. 

CRF occurs in tbe very advanced stages of stable COPD when the degree of airflow obstruction becomes severe (26,27). In a report of hospital discharges, respiratory failure accounted for 37% of in-hospital mortality in patients with COPD, as either a primary or a secondary discharge diagnosis (28). Treatment of respiratory failure accounts for a large part of the economic burden of tbe disease. Admission to the hospital for COPD exacerbations, associated with respiratory failure, accounts for approximately two-thirds of the direct costs of COPD (29). The role of HMV in COPD is discussed elsewhere in this text. 

Secondary Discharge EHiuent 170 77 E E E municipal garbage incinerator 6ue gas from secondary chamber after passing through scrubber, marble bed phis enbained hquor at pH 3-4. Agitation moderate aeratkm extensive. 51 days... 

Secondary Discharge Effluent 200 93 — E E E municipal refuse incineialni flue gas effluent alter H,0 scrubbing. En-vironfflont should be mainly steam with entrained impurities, extensive aeration... 

Secondary Discharge EHiuent — 300 149 - E E C municipal fcfuse incinerator water quenched flue gas. acid chloride environment pH range about 1.6, extensive aeration... 

Sebacic acid 50, 166, 706, 739 Secondary discharge effluent - 706 Seed oil - 835... 

FIGURE 5.4 Interface showing area affected by a secondary discharge. 

Optimizing conditions for low oxides The formation of oxide species can be problematic in some sample types. For example, in geochemical applications it is quite common to sacrifice sensitivity by lowering the nebulizer gas flow and increasing the RF power to reduce the formation of rare earth oxides, which can spectrally interfere with the determination of other analytes. Unfortunately, these conditions will change the electrical characteristics of the plasma, which can induce a secondary discharge. 

Even though most modern ICP-MS interfaces have been designed to minimize the effects of the secondary discharge, it should not be taken for granted that they can... 

Buildup of solids in the sample injector, producing signal drift Changes in the electrical characteristics of the plasma, generating a secondary discharge and increasing ion energies... 

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