Reverse recovery issues

Incidentally, Schottky diodes do not have any reverse recovery current issues, but they do have some body capacitance, which can produce similar effects. However, that fear has always proven to be exaggerated. I have personally not seen any application having a performance issue explicitly related to a bad Schottky. The only exception was a case where the leakage current of the Schottky was so high, it was prematurely tripping the current comparators inside the switcher IC. And there was also a reliability issue once, concerning the dV/df rating of a commercial Schottky. Both these issues are discussed elsewhere in this book. 

There were a number of practical and theoretical issues to be addressed. A key scientific question was whether fixation in formalin modified antigens in a reversible or irreversible manner. To be more specific, was there any theoretical or prior scientific evidence that the effects of formalin fixation on proteins could be reversed, and if reversed, was the structure of protein restored to a sufficient degree for recovery of antigenicity With these key questions in mind, one of the authors (Shi) spent many days and nights in 1988 searching the chemical literature under somewhat adverse conditions, with a second job as an apprentice in a supermarket, and prior to the increased efficiency of such searches that is afforded today by the Internet and online databases. The answer was finally found in a series of studies of the chemical... 

Different reversed phase [195,239,240], mixed mode (ion exchange and reversed phase) SPE cartridges [173,218] and online SPE column [193, 238] have been also reported for samples preparation and extraction. Some of these assays combined both PP and SPE in order to achieve an extensive sample cleanup [193, 195, 238-240], Likewise SPE, LLE provides cleaner plasma extracts than PP. Nevertheless, LLE procedure does not always provide satisfactory results with regard to extraction recovery and selectivity, especially with polar analytes and particularly in the case of multicomponent analysis such as in drug-metabolism studies, where analytes polarity varies widely. This issue was addressed by Zweigenbaum J and Henion J [235] and extraction solvent optimization, using isoamyl alcohol, to achieve acceptable extraction selectivity and recovery for polar analytes has been discussed. 

Membrane technology may become essential if zero-discharge mills become a requirement or legislation on water use becomes very restrictive. The type of membrane fractionation required varies according to the use that is to be made of the treated water. This issue is addressed in Chapter 35, which describes the apphcation of membrane processes in the pulp and paper industry for treatment of the effluent generated. Chapter 36 focuses on the apphcation of membrane bioreactors in wastewater treatment. Chapter 37 describes the apphcations of hollow fiber contactors in membrane-assisted solvent extraction for the recovery of metallic pollutants. The apphcations of membrane contactors in the treatment of gaseous waste streams are presented in Chapter 38. Chapter 39 deals with an important development in the strip dispersion technique for actinide recovery/metal separation. Chapter 40 focuses on electrically enhanced membrane separation and catalysis. Chapter 41 contains important case studies on the treatment of effluent in the leather industry. The case studies cover the work carried out at pilot plant level with membrane bioreactors and reverse osmosis. Development in nanofiltration and a case study on the recovery of impurity-free sodium thiocyanate in the acrylic industry are described in Chapter 42. 

N. Ferguson and J. Browne, Issues in End-of-Life Product Recovery and Reverse Logistics, Production Planning and Control, 12(5), 534-547 (2001). 

Figure 12-3 shows the effect that k has on the volume required for 100% recovery. When highly adsorbed interferences are not an issue, neat acetonitrile or methanol can be used to elute the analytes from reversed-phase adsorbents. Also, nonpolar solvents such as methylene chloride can be used on these adsorbents for very hydro-phobic analytes, as long as a cartridge drying step is first employed to remove all water. For silica adsorbents, highly polar eluents such as neat ethyl acetate, acetonitrile, or methanol can be used. 

Under a guarantee agreement, the originator is able to recover an amount equal to the net realised losses on the reference pool of loans, including the costs incurred in the foreclosure and recovery process, in return for a periodic payment of a guarantee fee. This fee is calculated to make up any shortfall between the interest received on the credit-linked note collateral pool and the expenses and interest costs of the issuing SPV. Realised losses are applied in reverse sequential order to the notes, by can-... 

Sasikumar P, Kannan G (2008) Issues in reverse supply chains, part I end-of life product recovery and inventory management-an overview. Int J Sustain Eng 1(3) 154-172... 

When reactions are reversible or products unstable, it is attractive to int ate recovery and (bio-)reaction, that is in situ product removal (ISPR). Compatibility of bioconversion and separation conditions is a key issue in ISPR. It will be demonstrated in a later section that constraints in an integrated system are completely different from those in the individual, non-int ated process steps. It may also be attractive to combine separation steps. A well-known example is crystallization with a withdrawal of coarse crystals (integration of molecular and mechanical separations). Often, an optimal integrated system will operate imder conditions that are not equal to those of the individual and non-integrated conversion and separation steps. This is process integration at the level of unit operations. 

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