896 research outputs found
Inhibition of adriamycin-promoted microsomal lipid peroxidation by β-carotene, α-tocopherol and retinol at high and low oxygen partial pressures
AbstractIron-dependent peroxidation of rat liver microsomes, enhanced by adriamycin, was measured in the presence of increasing concentrations of α-tocopherol, β-carotene and retinol at low and high pO2. β-Carotene and α-tocopherol inhibited lipid peroxidation by more than 60% when present at concentrations greater than 50 nmol/mg microsomal protein at both high and low pO2. Retinol inhibited peroxidation by 39% at concentrations greater than 100 nmol/mg microsomal protein. This maximal level of inhibition by retinol was unaltered by pO2. However, β-carotene was more effective than α-tocopherol or retinol at a pO2 of 4 mmHg, whereas α-tocopherol was more effective under aerobic conditions. Since adriamycin-dependent lipid peroxidation is maximal at low pO2, β-carotene may play a role in protecting against this process
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Investigation on the removal of the cavitation erosion risk in a control orifice inside a prototype diesel injector
A CFD investigation is in progress to study the cavitation characteristics and potential erosion risks of a control orifice in a prototype injector. An early design of the orifice resulted in cavitation erosion after endurance testing. A design modification eliminated the erosion and subsequent prototypes were free from damage. Initial results for the two designs using different simulation methods are discussed, along with the effects of different rates of evaporating and condensing mass transfer. Preliminary findings on possible erosion risk indicators comparing the eroding with the non-eroding design are presented
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Cavitation erosion risk indicators for a thin gap within a diesel fuel pump
Real industrial examples have been used to evaluate the viability of several cavitation erosion risk indicators (ERIs). Industry standard endurance tests resulted in non-critical cavitation erosion of a shoe and shoe-guide assembly in a high-pressure fuel pump. A design modification was made which eliminated the erosion. Transient CFD simulations of the two designs were run. The distribution and intensity of the resulting ERIs were evaluated against photographic evidence of erosion taken after endurance testing. Details of the component dynamics and the resulting cavitation formation and collapse are presented, along with an analysis of the ERIs for their potential usefulness. Of the 11 ERIs studied, two were found to be particularly good indicators, one of which is newly derived for this research. It is now anticipated that using these ERIs to guide product design and development will save considerable time and cost
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