265,240 research outputs found
Analytical and experimental evaluations of the effect of broad property fuels on combustors for commercial aircraft gas turbine engines
The impacts of broad property fuels on the design, performance, durability, emissions, and operational characteristics of current and advanced combustors for commercial aircraft gas turbine engines were studied. The effect of fuel thermal stability on engine and airframe fuel system was evaluated. Tradeoffs between fuel properties, exhaust emissions, and combustor life were also investigated. Results indicate major impacts of broad property fuels on allowable metal temperatures in fuel manifolds and injector support, combustor cyclic durability, and somewhat lesser impacts on starting characteristics, lightoff, emissions, and smoke
Compactification of a map which is mapped to itself
We prove that if is a selfmap of a set such that \bigcap
\{T^{n}X: n\in N}\} is a one-point set, then the set can be endowed with a
compact Hausdorff topology so that is continuous.Comment: 5 page
Temperature perturbation model of the opto-galvanic effect in CO2-laser discharges
A detailed discharge model of the opto-galvanic effect in molecular laser gas mixtures is developed based on the temperature perturbation or discharge cooling mechanism of Smith and Brooks (1979). Excellent agreement between the model and experimental results in CO2 laser gas mixtures is obtained. The model should be applicable to other molecular systems where the OGE is being used for laser stabilisation and as a spectroscopic tool
A simplified, compact static shift register
Shift register was developed which uses only one D type flip-flop and improves packaging density by approximately 25% over the usual arrangement. Circuit is compromise between full master-slave arrangement and dynamic shift register, with limitation only of length of time that clock can be held high during new data entry
Television viewing time and risk of incident obesity and central obesity: the English longitudinal study of ageing
Background Research suggests television viewing time may be associated with incident obesity and central obesity in young adults. No study has investigated these associations in older English adults. The aim of this study was to investigate longitudinal associations between television viewing time and incident obesity and central obesity in a sample of older English adults. Analyses of data from the English Longitudinal Study of Ageing. At baseline (2008), participants reported their television viewing time. Research nurses recorded obesity and central obesity by body mass index and waist circumference, respectively, at four year follow-up. Associations between television viewing time and incident obesity (BMI > 30 kg/m2) and central obesity (waist >102 cm men; > 88 cm women) at four year follow-up were examined using adjusted logistic regression. Participants gave full written informed consent to participate in the study and ethical approval was obtained from the London Multicentre Research Ethics Committee. Results A total of 3777 initially non-obese participants (aged 64.8 ± 8.6 yrs, 46.4% male) were included in the analyses using BMI as an outcome and 2947 for the analyses using waist circumference. No significant associations were found between television viewing time and incident obesity. A significant association was found between watching ≥6 hrs/d of television (compared to <2 hrs/d) and central obesity (Odds Ratio 1.48; 95% confidence interval 1.07 to 2.03) after adjustment for covariables including physical activity. Conclusions In this sample of older community dwelling English adults greater television viewing time was associated with incident central obesity, but not total obesity when measured by BMI. Interventions to reduce the incidence of central obesity in this age group that focus on reducing TV time, as well as targeting other health behaviours (eg, increasing physical activity levels, improving dietary intake) might prove useful
A new HCN maser in IRAS 15082-4808
We have identified a new vibrational HCN maser at 89.087 GHz in the
asymptotic giant branch (AGB) star IRAS 15082-4808, a maser which is thought to
trace the innermost region of an AGB envelope. The observations of this maser
at three epochs are presented: two positive detections and one null detection.
The line profile has varied between the positive detections, as has the
intensity of the maser. The major component of the maser is found to be offset
by -2.0+/-0.9 km/s with respect to the systemic velocity of the envelope, as
derived from the 88.631 GHz transition of HCN. Similar blueshifts are measured
in the other 9 sources where this maser has been detected. Maser variability
with pulsation phase has been investigated for the first time using the 10
stars now available. Comparisons with AGB model atmospheres constrain the
position of the formation region of the maser to the region between the
pulsation shocks and the onset of dust acceleration, between 2 and 4 stellar
radii.Comment: 11 pages, 10 figures, accepted MNRAS, minor correction to equation
Job Search Strategies and Labor Market Success
This study examines the relation between job search strategies and two measures of labor market success, starting salary and number of job offers received, in a sample of graduating MBAs. Controlling for applicant and market characteristics, we find that job search strategy is related to both starting salary and number of job offers, but most strongly to the latter measure of labor market success. Beginning the job search earlier, greater numbers of employer contacts, and not accepting the first job offer all contribute to greater labor market success. These findings suggest that individuals take concrete steps to achieve greater labor market success than would be expected based on their personal attributes and market conditions
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