4,992 research outputs found
Preliminary compressor design study for an advanced multistage axial flow compressor
An optimum, axial flow, high pressure ratio compressor for a turbofan engine was defined for commercial subsonic transport service starting in the late 1980's. Projected 1985 technologies were used and applied to compressors with an 18:1 pressure ratio having 6 to 12 stages. A matrix of 49 compressors was developed by statistical techniques. The compressors were evaluated by means of computer programs in terms of various airline economic figures of merit such as return on investment and direct-operating cost. The optimum configuration was determined to be a high speed, 8-stage compressor with an average blading aspect ratio of 1.15
Solitary waves and their stability in colloidal media: semi-analytical solutions
Spatial solitary waves in colloidal suspensions of spherical dielectric
nanoparticles are considered. The interaction of the nanoparticles is modelled
as a hard-sphere gas, with the Carnahan-Starling formula used for the gas
compressibility. Semi-analytical solutions, for both one and two spatial
dimensions, are derived using an averaged Lagrangian and suitable trial
functions for the solitary waves. Power versus propagation constant curves and
neutral stability curves are obtained for both cases, which illustrate that
multiple solution branches occur for both the one and two dimensional
geometries. For the one-dimensional case it is found that three solution
branches (with a bistable regime) occur, while for the two-dimensional case two
solution branches (with a single stable branch) occur in the limit of low
background packing fractions. For high background packing fractions the power
versus propagation constant curves are monotonic and the solitary waves stable
for all parameter values. Comparisons are made between the semi-analytical and
numerical solutions, with excellent comparison obtained.Comment: Paper to appear in Dynamics of Continuous, Discrete and Impulsive
Systems, Series
Competitive Analysis and Market Power of China’s Soybean Import Market
This research conducts a competitive structure analysis of the Chinese soybean import market which leads to the hypothesis that China’s soybean importers may have stronger market power in China’s soybean import market. Then, this research develops and simultaneously estimates a two-country partial equilibrium trade model to test U.S.-China market power of soybean trade. The empirical result supports our hypothesis that Chinese soybean importers have stronger market power relative to U.S. soybean exporters. This Chinese market power can be countered by U.S. and South American companies through developing new and expanding existing markets for soybeans throughout the world and investing in Chinese soybean storage and crushing capacity.Chinese soybean import market, competitive structure analysis, market power, two-country partial equilibrium trade model, International Relations/Trade, Marketing, Research Methods/ Statistical Methods, Q10, Q12, Q17,
Planning a Family:priorities and concerns in rural Tanzanmia
A fertility survey using qualitative and quantitative techniques described a high fertility setting (TFR 5.8) in southern Tanzania where family planning use was 16%. Current use was influenced by rising parity, educational level, age of last born child, breastfeeding status, a\ud
preference for longer than the mean birth interval (32 months), not being related to the household head, and living in a house with a tin roof. Three principal concerns amongst women were outlined from the findings. First, that there is a large unmet need for family planning services in the area particularly among teenagers for whom it is associated with induced abortion. Second, that family planning is being used predominantly for spacing but fears\ud
associated with it often curtail effective use. Third, that service provision is perceived to be lacking in two main areas — regularity of supply, and addressing rumours and fears associated with family planning. Reproductive health interventions in the area should ultimately be more\ud
widespread and, in particular, abortion is highlighted as an urgent issue for further research.\ud
The potential for a fast and positive impact is high, given the simplicity of the perceived needs of\ud
women from this study. (Afr J Reprod Health 2004; 8[2]:111-123)\u
Poisoning with the recreational drug paramethoxyamphetamine ("death")
The document attached has been archived with permission from the editor of the Medical Journal of Australia. An external link to the publisher’s copy is included.Objective: To describe the clinical features of paramethoxyamphetamine (PMA; "death") poisoning and to compare these with those of people with self-reported "ecstasy" poisoning. Design: Retrospective casenote review. Participants and setting: 22 patients who presented to the Emergency Department of the Royal Adelaide Hospital (RAH), a major metropolitan teaching hospital, between 1 January 1996 and 31 December 1998 with PMA poisoning identified through urine drug screens; and 61 patients with self-reported ecstasy poisoning between 1 September 1997 and 31 December 1998 found through the hospital databases. Results: Patients with PMA poisoning presented with tachycardia (64%), hyperthermia (temperature > 37.5ºC; 36%), coma (41%), seizures (32%), arrhythmias (23%), and QRS intervals 100 ms (50%) with greater frequency and often greater severity than those with self-reported ecstasy poisoning. Two patients with PMA poisoning presented with severe hypoglycaemia (blood glucose level, 7.5 mmol/L). Conclusions: At our hospital, PMA poisonings accounted for most of the severe reactions among people who believed they had taken ecstasy. Hypoglycaemia and hyperkalaemia may be specific to PMA poisoning. PMA toxicity should be suspected with severe or atypical reactions to "ecstasy", and confirmed by chromatographic urine drug screens.Liang Han Ling, Colin Marchant, Nicholas A. Buckley, Michael Prior and Rod J. Irvin
New Candidate Interstellar Particle in Stardust IS Aerogel Collector: Analysis by STXM and Ptychography
The Stardust Interstellar Preliminary Examination (ISPE) reported in 2014 the discovery of 7 probable contemporary interstellar (IS) particles captured in Stardust IS Collector aerogel and foils. The ISPE reports represented work done over 6 years by more than 60 scientists and >30,000 volunteers, which emphasizes the challenge identifying and analyzing Stardust IS samples was far beyond the primary Stardust cometary collection. We present a new potentially interstellar particle resulting from a continuation of analyses of the IS aerogel collection
Triboelectrostatic Separation of Mineral Matter from Slovakian Coals
V èlánku sú diskutované niektoré technické aspekty triboelektrostatickej separácie a výs-ledky aplikácie tohto postupu pri úprave troch typov uhlia, konkrétne energetického uhlia z Cíg¾a, Handlovej a Novák. Bolo zistené, e úèinnos separácie ve¾mi úzko závisí na druhu separovan uhlia. Prvé výsledky preukázali súvislos medzi úèinnosou separácie obsahom popola v uhlí
- …
