Passivation procedures

Good housekeeping practices to prevent the accumulation of tantalum dust and a proper passivation procedure will prevent most tantalum fires. AH equipment used to handle the powder should be properly grounded and contact with hot surfaces or flames should be avoided. 

Development of Filter Flux Maintenance (Passive) Procedure... 285... 

PPO reaction (Fig. 10). This is consistent with decreasing the rates of both reactions (4) and (5) with the silanization while only decreasing the rate of reaction 5 with the PPO treatment. There remains substantial room for improving these passivation procedures, and other, as yet unexplored, methods may prove superior to those described here. However, the results achieved so far demonstrate the promise of this approach. 

Two immunization procedures designed to enhance the immune response to multiple antigen mixtures have been reported recently. The cascade immunization technique (20) utilized in vitro depletion of E. coli proteins (ECPs) which had previously elicited an antibody response. The removal of these dominant immunogens from the mixture was accomplished by immunoabsorption with antibodies obtained from an earlier antiserum. The passive immunization procedure (21) relied on in vivo blocking of strong immunogens by the concurrent administration of early antiserum obtained previously. This latter report demonstrated the presence of an apparently poorly immunogenic ECP to which a humoral response could only be elicited by this passive procedure. 

The electron diffraction patterns of these samples paralleled those observed for the samples reacted in the electron microscope, i.e., samples reduced in the flow reactor at 1120 K showed that the titanium oxide had been completely converted to Ti407, whereas samples treated at 970 K showed only the rutile form or T102 in agreement with the work of Bell and coworkers (15). One anomalous finding occurred with a sample that was treated at 1120 K for which the passivation procedure was inadvertently omitted the diffraction pattern showed no evidence of Ti Oy. 

The organic layers were grown onto sulfur-passivated GaAs(lOO) substrates by organic molecular beam deposition (OMBD) in an ultra high vacuum chamber (UHV) with 7 X 10 mbar base pressure. The passivation procedure is described in Ref. [1]. 

Surface plays an important role in excited state relaxation processes. In the ideal case of a three-dimensionally confined exciton, one expects to see strong exciton luminescence due to enhanced overlap of the electron and hole wavefunction. The radiative rate of the exciton should increase with increasing cluster size. In reality, this is generally not observed. Most of the luminescence spectra of semiconductor nanoclusters consist of a stokes-shifted broad luminescence band, usually attributed to emission from surface defects. Sometimes near the band edge, an exciton-like luminescence band can be observed. Various passivation procedures have been used to enhance the exciton luminescence. These are discussed in Section III. 

Surface defects such as dangling bonds and vacancies may, in principle, be removed by chemical passivation techniques. A successful passivation procedure should result in the disappearance of defect luminescence and the appearance of strong exciton luminescence. Many chemicals have been tried for this purpose but with few successes. The two most successful passivation techniques developed so far involve the use of ammonia [50] and hydroxide ion [35]. In both cases, defect luminescence is greatly reduced with the... 

Fluid displacive resin-embedding of wet sediment is a passive procedure, samples are never physically dry and the fabric is supported by fluid throughout. Chemical dehydration prevents the cracking (common in vacuum dried sediment), and the technique requires no specialized drying, or resin-impregnating equipment. Water-saturated samples are more successfully embedded using fluid replacement than those which are partially dry. 

To retard weathering discoloration and improve atmospheric corrosion resistance, in addition to preventing wet storage staining, chromate passivation procedures have been developed. 

Have all commissioning tests or inspections been identified (for example, pressure or leak tests, passivating procedures) ... 

These equations do not depend on the control Q (jacket-surroundings heat exchange rate), meaning that, as expected, the pair Qj-zt does not have RD = 1. To remove this high RD obstacle for robustness, let us recall the backstepping passivation procedure, for the input-output pair u-z and regard the measured jacket temperature Tj (= Xs) as a virtual control (instead of Qj) [22], solve the last equation set for (M, w, Tj), and obtain the primary inverse (Eq. 10)... 

Question by W. M. Duke, Space Technology Lab. The passivation procedure associated with utilization of fluorine presumably deposits a protective coating on the pickled metal surface, a coating tremendously necessary. If the part in question is subject to structural loading, such as flexure, or to shock, it can be supposed that the protective coating could crack, or even worse, flake off. 

The oxide formed on stainless steel is electrically conductive. Stainless steel has a poor thermal conductivity and should not be used in applications requiring good thermal conductivity. Welding of stainless steel can affect the corrosion resistance in the heat-affected zone (HAZ). This can be controlled by limiting the amount of carbon in the material to minimize formation of chromium carbide and by using special passivation procedures. 

---