11,714 research outputs found
Density dependence of the pairing interaction and pairing correlation in unstable nuclei
This work aims at a global assessment of the effect of the density dependence
of the zero-range pairing interaction. Systematic
Skyrme-Hartree-Fock-Bogoliubov calculations with the volume, surface and mixed
pairing forces are carried out to study the pairing gaps in even-even nuclei
over the whole nuclear chart. Calculations are also done in coordinate
representation for unstable semi-magic even-even nuclei. The calculated pairing
gaps are compared with empirical values from four different odd-even staggering
formulae. Calculations with the three pairing interactions are comparable for
most nuclei close to -stability line. However, the surface interaction
calculations predict neutron pairing gaps in neutron-rich nuclei that are
significantly stronger than those given by the mixed and volume pairing. On the
other hand, calculations with volume and mixed pairing forces show noticeable
reduction of neutron pairing gaps in nuclei far from the stability.Comment: 9 pages, 10 figures, 3 tables, printer-friendl
Design of serrate-semi-circular riblets with application to skin friction reduction on engineering surface
Drag reduction in wall-bounded flows can be achieved by the passive flow control technique through the application of bio-inspired riblet surfaces. This paper presents the innovative design of Serrate-Semi-Circular riblet surfaces particularly focusing on the intrinsic relationship between the riblet features and the turbulent boundary layer structure resulting from these surfaces in engineering applications. The available experimental facilities, instrumentation (i.e. hotwire) and measurement techniques (i.e. velocity spectra) have been employed to investigate the boundary layer velocity profiles and skin friction for flat plate and Serrate-Semi-Circular riblet surfaces. Both the simulation and experimental wind tunnel testing results show that the Serrate-Semi-Circular riblet surface can provide 7% drag reduction, which is better than other riblet configurations, such as V and U shaped ones
Food Safety Knowledge and Practice Among Community in Sg. Pelek, Sepang, Selangor Darul Ehsan
Food safety is a basic requirement of food quality. It is an increasingly important public health issue to prevent and control food borne illnesses. A cross-sectional study was designed to determine level of knowledge and practice on food safety, to determine the association between knowledge and practice, and also to identify the association between socio-demographic factors and practice score of the population studied. This study was conducted among adult population in Taman Bahagia, Sungai Pelek, Sepang, Selangor Darul Ehsan. Data were collected using an interviewed structured questionnaire. A stratified random sampling was performed to obtain houses, followed by simple random sampling to select sample in the house. A total of 115 data sets were analysed using Statistical Package for Social Sciences (SPSS) version 20.0. Analysis showed that 35% of respondents have poor level of knowledge on food safety, whereas 27% of the respondents have poor level of practices on food safety. Multiple linear regression revealed that there are a significant association between education level (p<0.001), Adj b=2.57 (95% CI: 1.15, 3.99) and gender (p=0.048), Adj b=1.15 (95% CI: 0.01, 2.29) with practice score on food safety. Therefore, health promotion and education on the importance of practicing food safety at home should be focused to prevent further unwanted health effects
Superconductivity and Magnetism in REFeAsO1-xFx (RE=Rare Earth Elements)
Fluoride-doped iron-based oxypnictides containing rare-earth gadolinium
(GdFeAsO0.8F0.2) and co-doping with yttrium (Gd0.8Y0.2FeAsO0.8F0.2) have been
prepared via conventional solid state reaction at ambient pressure. The
non-yttrium substituted oxypnictide show superconducting transition as high as
43.9 K from temperature dependent resistance measurements with the Meissner
effect observed at a lower temperature of 40.8 K from temperature dependent
magnetization measurements. By replacing a small amount of gadolinium with
yttrium Tc was observed to be lowered by 10 K which might be caused by a change
in the electronic or magnetic structures since the crystal structure was not
altered.Comment: 4 pages, 4 figures, Journal of Physics: Conference Series
(Proceedings in the LT25 Low Temperature Physics Conference) Submitte
Structural relaxation in a system of dumbbell molecules
The interaction-site-density-fluctuation correlators, the dipole-relaxation
functions, and the mean-squared displacements of a system of symmetric
dumbbells of fused hard spheres are calculated for two representative
elongations of the molecules within the mode-coupling theory for the evolution
of glassy dynamics. For large elongations, universal relaxation laws for states
near the glass transition are valid for parameters and time intervals similar
to the ones found for the hard-sphere system. Rotation-translation coupling
leads to an enlarged crossover interval for the mean-squared displacement of
the constituent atoms between the end of the von Schweidler regime and the
beginning of the diffusion process. For small elongations, the superposition
principle for the reorientational -process is violated for parameters
and time intervals of interest for data analysis, and there is a strong
breaking of the coupling of the -relaxation scale for the diffusion
process with that for representative density fluctuations and for dipole
reorientations.Comment: 15 pages, 14 figures, Phys. Rev. E in pres
QCD Effects in High Energy Processes
In this talk, some important QCD effects in Higgs physics, supersymmetry and
top physics, as well as the factorization and resummation techniques in QCD are
reviewed.Comment: LaTeX, 13 pages, uses ws-ijmpa.cls. Based on an invited talk at the
International Conference on QCD and Hadronic Physics, Beijing, China, June
16--20, 2005. Minor change
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