American Society of Mechanical Engineers

About: American Society of Mechanical Engineers is a nonprofit organization based out in New York, New York, United States. It is known for research contribution in the topics: Gas compressor & Turbine. The organization has 27 authors who have published 34 publications receiving 343 citations. The organization is also known as: ASME.

Noninvasive imaging predicts failure load of the spine with simulated osteolytic defects.

Abstract: Background: The clinical management of lytic tumors of the spine is currently based on geometric measurements of the defect. However, the mechanical behavior of a structure depends on both its material and its geometric properties. Quantitative computed tomography and dual-energy x-ray absorptiometry were investigated as noninvasive tools for measuring the material and geometric properties of vertebrae with a simulated lytic defect. From these measures, yield loads were predicted with use of composite beam theory. Methods: Thirty-four fresh-frozen cadaveric spines were segmented into functional spinal units of three vertebral bodies with two intervertebral discs at the thoracic and lumbar levels. Lytic defects of equal size were created in one of three locations: the anterior, lateral, or posterior region of the vertebra. Each spinal unit was scanned with use of computed tomography and dual-energy x-ray absorptiometry, and axial and bending rigidities were calculated from the image data. Each specimen was brought to failure under combined compression and forward flexion, and the axial load and bending moment at yield were recorded. Results: Although the relative defect size was nearly constant, measured yield loads had a large dispersion, suggesting that defect size alone was a poor predictor of failure. However, image-derived measures of structural rigidity correlated moderately well with measured yield loads. Furthermore, with use of composite beam theory with quantitative computed tomography-derived rigidities, vertebral yield loads were predicted on a one-to-one basis (concordance, rc = 0.74). Conclusions: Although current clinical guidelines for predicting fracture risk are based on geometric measurements of the defect, we have shown that the relative size of the defect alone does not account for the variation in vertebral yield loads. However, composite beam theory analysis with quantitative computed tomography-derived measures of rigidity can be used to prospectively predict the yield loads of vertebrae with lytic defects. Clinical Relevance: Image-predicted vertebral yield loads and analytical models that approximate loads applied to the spine during activities of daily living can be used to calculate a factor of fracture risk that can be employed by physicians to plan appropriate treatment or intervention.

Axial-Flow Turbines

Abstract: This chapter focuses on axial-flow turbines that are the most widely employed turbines using a compressible fluid Axial-flow turbines power most of the gas turbine units and they are more efficient than radial-inflow turbines in most operational ranges They are also used in steam turbine design; however, there are some significant differences between the axial-flow turbine design for a gas turbine and the design for a steam turbine Axial-flow turbines are now designed with a high work factor to obtain lower fuel consumption and reduce the noise from the turbine Lower fuel consumption and lower noise requires the design of higher by-pass ratio engines, and a high by-pass ratio engine in turn requires various turbine stages to drive the high-flow, low-speed fan The flow in axial-flow turbines enters and leaves in the axial direction There are two types of axial turbines: impulse type and reaction type Most axial flow turbines consist of more than one stage The front stages are usually impulse (zero reaction) and the later stages have about 50% reaction The impulse stages produce about twice the output of a comparable 50% reaction stage, while the efficiency of an impulse stage is less than that of a 50% reaction stage The high temperatures that are available in the turbine section have resulted from the improvements of the metallurgy of the blades in the turbines Development of directionally solidified blades as well as the new single-crystal blades, with the new coating cooling schemes, is responsible for the increase in firing temperatures The high pressure ratio in the compressor also causes the cooling air used in the first stages of the turbine to become hot

Impact of environmental regulations on green electronics manufacture

Abstract: Purpose – The purpose of this paper is to investigate the electronic industry's reaction to environmental regulations specifically in terms of lead‐free solders and halogen‐free flame‐retardants (FRs).Design/methodology/approach – This work achieves its objective by discussing the various international regulations pertaining to electronics manufacturing and relating the industry reactions to those regulations. The electronics industry is pursuing lead‐free solders and halogen‐free FRs, in part due to regulations. However, the paper includes examples of how the industry is successful in implementing environmentally friendly changes.Findings – The authors compared regulations from Japan, the European Union, and the US. While the regulations themselves vary in scope, industry actions to find alternatives do have common purposes. Electronics manufacturers recognize that environmentally motivated changes are beneficial in terms of waste minimization. Regardless of the regulatory motivation, minimization does l...

Effect of Prime-Mover Speed Governor Characteristics on Power-System Frequency Variations and Tie-Line Power Swings

Abstract: In the normal steady-state operation of a power system, proper load division, frequency, and time are maintained by manual or automatic system control, while the transient swings occasioned by load changes are absorbed by the inertias and speed governors of the individual generating units. With improvements in reliability and performance of systems and their interconnections, it is a natural development that further careful attention and study be given to the basic speed governors and their effects on system operation.1,5,6 It is desirable to determine the requirements which a good governing mechanism should fulfill, and the effects of specific governor and system characteristics on over-all system performance. Moreover, under certain conditions some governors may accentuate rather than reduce the magnitudes of the frequency swings, and it is desirable to know the conditions for which this may occur.

Alteration of benzo(a)pyrene biotransformation by resveratrol in ApcMin/+ mouse model of colon carcinogenesis

Abstract: Epidemiological surveys have revealed that environmental and dietary factors contribute to most of the human cancers. Our earlier studies have shown that resveratrol (RVT), a phytochemical reduced the tumor number, size and incidence of dysplasias induced by benzo(a)pyrene (BaP), an environmental toxicant in the ApcMin/+ mouse model of colon cancer. In this study we investigated to ascertain whether the preventive effects of RVT on BaP-induced colon carcinogenesis is a result of altered BaP biotransformation by RVT. For the first group of mice, 100 μg BaP/kg bw was administered in peanut oil via oral gavage over a 60 day period. For the second group, 45 μg RVT/kg bw was co-administered with BaP. For the third group, RVT was administered for 1 week prior to BaP exposure. Blood, colon and liver were collected from control and BaP/RVT-treated mice at 60 days post-BaP & RVT exposure. We have assayed activities and expression (protein & mRNA) of drug metabolizing enzymes such as cytochrome P4501A1 (CYP1A1), CYP1B1, and glutathione-S-transferase (GST) in colon and liver samples from the treatment groups mentioned above. An increased expression of CYP1A1 in liver and colon and of CYP1B1 in liver of BaP-treated mice was seen, while RVT inhibited the extent of biotransformation mediated by these enzymes in the respective tissue samples. In the case of GST, an increased expression in colon of BaP alone-treated mice was noted when RVT was administered prior to BaP or simultaneously with BaP. However, there is no change in liver GST expression between BaP and RVT treatment groups. The concentrations of BaP aqueous (phase II) metabolites were found to be greater than the organic (phase I) metabolites, suggesting that RVT slows down the phase I metabolism (metabolic activation) of BaP, while enhancing phase II metabolism (detoxification). Additionally, the BaP-DNA adduct concentrations measured in colon and liver of BaP + RVT-treated mice were low relative to their BaP counterparts. Taken together, our findings strongly suggest that RVT alleviates BaP-induced colon carcinogenesis by impairing biotransformation pathways and DNA adduct formation, and therefore holds promise as a chemopreventive agent.