9,082 research outputs found
A system-level mathematical model for evaluation of power train performance of load-leveled electric-vehicles
The power train performance of load leveled electric vehicles can be compared with that of nonload leveled systems by use of a simple mathematical model. This method of measurement involves a number of parameters including the degree of load leveling and regeneration, the flywheel mechanical to electrical energy fraction, and efficiencies of the motor, generator, flywheel, and transmission. Basic efficiency terms are defined and representative comparisons of a variety of systems are presented. Results of the study indicate that mechanical transfer of energy into and out of the flywheel is more advantageous than electrical transfer. An optimum degree of load leveling may be achieved in terms of the driving cycle, battery characteristics, mode of mechanization, and the efficiency of the components. For state of the art mechanically coupled flyheel systems, load leveling losses can be held to a reasonable 10%; electrically coupled systems can have losses that are up to six times larger. Propulsion system efficiencies for mechanically coupled flywheel systems are predicted to be approximately the 60% achieved on conventional nonload leveled systems
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Towards a Theory of Practice: Critical Transdisciplinary Multiliteracies
About the book: Education institutions and organizations throughout the world are currently being held accountable for achieving and maintaining historically unmatched standards of academic quality and performance. Accreditation bodies; policy makers; boards of trustees; and teacher, parent, and student groups all place educational institutions and organizations under unprecedented accountability pressures. The aim of this volume is to explore and better understand how these pressures are impacting a broad range of social and cultural issues and, subsequently, how these issues impact student motivation and learnin
Utilization of waste heat in trucks for increased fuel economy
Improvements in fuel economy for a broad spectrum of truck engines and waste heat utilization concepts are evaluated and compared. The engines considered are the diesel, spark ignition, gas turbine, and Stirling. The waste heat utilization concepts include preheating, regeneration, turbocharging, turbocompounding, and Rankine engine compounding. Predictions were based on fuel-air cycle analyses, computer simulation, and engine test data. The results reveal that diesel driving cycle performance can be increased by 20% through increased turbocharging, turbocompounding, and Rankine engine compounding. The Rankine engine compounding provides about three times as much improvement as turbocompounding but also costs about three times as much. Performance for either is approximately doubled if applied to an adiabatic diesel
Utilization of waste heat in trucks for increased fuel economy
The waste heat utilization concepts include preheating, regeneration, turbocharging, turbocompounding, and Rankine engine compounding. Predictions are based on fuel-air cycle analyses, computer simulation, and engine test data. All options are evaluated in terms of maximum theoretical improvements, but the Diesel and adiabatic Diesel are also compared on the basis of maximum expected improvement and expected improvement over a driving cycle. The study indicates that Diesels should be turbocharged and aftercooled to the maximum possible level. The results reveal that Diesel driving cycle performance can be increased by 20% through increased turbocharging, turbocompounding, and Rankine engine compounding. The Rankine engine compounding provides about three times as much improvement as turbocompounding but also costs about three times as much. Performance for either can be approximately doubled if applied to an adiabatic Diesel
Future fuels and engines for railroad locomotives. Volume 1: Summary
The potential for reducing the dependence of railroads on petroleum fuel, particularly Diesel No. 2 was investigated. Two approaches are studied: (1) to determine how the use of Diesel No. 2 can be reduced through increased efficiency and conservation, and (2) to use fuels other than Diesel No. 2 both in Diesel and other types of engines. Because synthetic hydrocarbon fuels are particularly suited to medium speed diesel engines, the first commercial application of these fuels may be by the railroad industry
Microbial degradation of plastics: Biofilms and degradation pathways
Plastics are recalcitrant polymers released in the environment through unpredicted use leading to accumulation and increased water and soil pollution. Transportation of these recalcitrant polymers in agricultural soil, sediment, and water has been causing concerns for environmentalists. Biofilm community adhered on plastic polymers have a significant contribution in their degradation as they warrant bioavailability of substrates, sharing of metabolites and increased cell viability thereby accelerating biodegradation. Metabolic enzymes of the microbes can be exploited as a potent tool for polymer degradation. However very little or no reports are available about the influence of biofilm and plastic degradation and vice versa. The present chapter reports the impact of biofilm microbes in the degradation of commonly used plastics. Furthermore, potent microorganisms and their interactions with the plastic surface has been deciphered, which would serve as a better understanding of the utilization of biofilm-based methods in the development of plastic waste management
GHG Mitigation Potentials from Energy Use and Industrial Sources in Annex I Countries: Methodology
This report documents the basic methodology of IIASA's GAINS model that has been used for comparing mitigation potentials for energy related and industrial emissions across Annex I Parties.
Additional information sources are available at gains.iiasa.ac.at/Annex1.htm
Role of oestradiol-17β in the regulation of synthesis and secretion of human chorionic gonadotrophin by first trimester human placenta
Inhibition of aromatase, a key enzyme in the biosynthesis of oestradiol-17β , by the addition of 1,4,6-androstatrien-3,17-dione resulted in a significant increase in the levels of immunoreactive human chorionic gonadotrophin (hCG) in the medium and tissue. This increase was partially reversed by the simultaneous addition of oestradiol-17β . These effects on the levels of immunoreactive hCG were also reflected by the increased levels of mRNA specific for the α and β subunits of hCG following the addition of the aromatase inhibitor. However, addition of tamoxifen resulted in a drastic decrease in the levels of both the messages. Based on these results, it is suggested that the synthesis of hCG is negatively modulated by oestradiol-17β in the human placenta
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