1,403 research outputs found
INGRES: a computer code for the rate of air ingress into an HTGR following a design-basis depressurization accident
The computer program INGRES was written to calculate the rate of air ingress into the prestressed concrete reactor vessel after a design-basis depressurization accident in a high-temperature gas-cooled reactor. The model includes the free convection loop that can occur in a cold-leg break, the expansion and contraction air exchange mechanisms, and the conversion of oxygen to carbon monoxide. Results are presented for the 2000-MW(t) Summit Power Station and the 3000-MW(t) Fulton Generating Station and are compared to computational results provided by the General Atomic Company. The results agree reasonably well even though some differences exist in the two models. (auth
Aplikasi Teknologi Bioengineering Jebakan Sedimen di Sub DAS Citanduy Hulu
Citanduy watershed has been classified as a critical watershed in West Java. Sedimentation load at Citanduy watershed reach 5 milion cubic meters/years. It is indicated that lagoon area âSegara Anakanâ was decreased about 823 hectars. Land use changes for cultivation area at Citanduy upland causes acceleration land degradation. Various efforts of the civil engineering and vegetative approach have been applied to control erosion and sedimentation. Alternative technology for controlling soil erosion and sedimentation is the application of sediment trap bioengineering. It is application on micro catchment area, environment-friendly, and easily adapted for the farmers community. The main for material of bioengineering sediment trap is made of Bamboo. Results of design that is applied in the critical area at Bukit Bitung up land (Citaduy upland) Kecamatan Tambaksari, Ciamis Region, measuring the width between 100 cm to 150 cm, whereas the height are between 80 cm to 100 cm. The application of this technology is effective sediment traps for micro catcment area of <5 hectars. Therefore for a broad cachment area more sediment traps are required. In a period of not more than 1.5 month, the sediment trap has been able to capture sediments up to 1 m3 per unit. The performance of sediment traps bioengineering also shown that bamboo as main components has grown up to not more than 30 days. The trapped sediments were restored back to the land for agricultural purposes after being add by agricultural waste. Sediments that have been processed at the same time also functions as soil amelioration or soil improvement
Auxiliary potential in no-core shell-model calculations
The Lee-Suzuki iteration method is used to include the folded diagrams in the
calculation of the two-body effective interaction between
two nucleons in a no-core model space. This effective interaction still depends
upon the choice of single-particle basis utilized in the shell-model
calculation. Using a harmonic-oscillator single-particle basis and the
Reid-soft-core {\it NN} potential, we find that overbinds
^4\mbox{He} in 0, 2, and model spaces. As the size of the
model space increases, the amount of overbinding decreases significantly. This
problem of overbinding in small model spaces is due to neglecting effective
three- and four-body forces. Contributions of effective many-body forces are
suppressed by using the Brueckner-Hartree-Fock single-particle Hamiltonian.Comment: 14 text pages and 4 figures (in postscript, available upon request).
AZ-PH-TH/94-2
Mass-luminosity relation for FGK main sequence stars: metallicity and age contributions
The stellar mass-luminosity relation (MLR) is one of the most famous
empirical "laws", discovered in the beginning of the 20th century. MLR is still
used to estimate stellar masses for nearby stars, particularly for those that
are not binary systems, hence the mass cannot be derived directly from the
observations. It's well known that the MLR has a statistical dispersion which
cannot be explained exclusively due to the observational errors in luminosity
(or mass). It is an intrinsic dispersion caused by the differences in age and
chemical composition from star to star. In this work we discuss the impact of
age and metallicity on the MLR. Using the recent data on mass, luminosity,
metallicity, and age for 26 FGK stars (all members of binary systems, with
observational mass-errors <= 3%), including the Sun, we derive the MLR taking
into account, separately, mass-luminosity, mass-luminosity-metallicity, and
mass-luminosity-metallicity-age. Our results show that the inclusion of age and
metallicity in the MLR, for FGK stars, improves the individual mass estimation
by 5% to 15%.Comment: 7 pages, 4 figures, 1 table, accepted in Astrophysics and Space
Scienc
Mass Dependence of M3Y-Type Interactions and the Effects of Tensor Correlations
The mass dependence of the M3Y-type effective interactions and the effects of
tensor correlations are examined. Two-body nuclear matrix elements are obtained
by the lowest order constrained variational (LOCV) technique with and without
tensor correlations. We have found that the tensor correlations are important
especially in the triplet-even (TE) and tensor-even (TNE) channels in order to
reproduce the G-matrix elements obtained previously. Then M3Y-type potentials
for inelastic scattering are obtained by fitting our two-body matrix elements
to those of a sum of Yukawa functions for the mass numbers A=24, A=40 and A=90.Comment: 13 pages, 6 table
Nuclear shell-model calculations for 6Li and 14N with different NN potentials
Two ``phase-shift equivalent'' local NN potentials with different
parametrizations, Reid93 and NijmII, which were found to give nearly identical
results for the triton by Friar et al, are shown to yield remarkably similar
results for 6Li and 14N in a (0+2)hw no-core space shell-model calculation. The
results are compared with those for the widely used Hamada-Johnson hard-core
and the original Reid soft-core potentials, which have larger deuteron D-state
percentages. The strong correlation between the tensor strength and the nuclear
binding energy is confirmed. However, many nuclear-structure properties seem to
be rather insensitive to the details of the NN potential and, therefore, cannot
be used to test various NN potentials. (Submitted to Phys. Rev. C on Nov. 9,
1993 as a Brief Report.)Comment: 12 text pages and 1 figure (Figure available upon request),
University of Arizona Physics Preprint (Number not yet assigned
Charge and Isospin Fluctuations in High Energy pp-Collisions
Charge and isospin event-by-event fluctuations in high-energy pp-collisions
are predicted within the Unitary Eikonal Model, in particular the fluctuation
patterns of the ratios of charged-to-charged and neutral-to-charged pions.
These fluctuations are found to be sensitive to the presence of unstable
resonances, such as and mesons. We predict that the
charge-fluctuation observable should be restricted to the interval
depending on the production ratio. Also, the
isospin fluctuations of the DCC-type of the ratio of neutral-to-charged pions
are suppressed if pions are produced together with mesons.Comment: Latex, 5 pages, no figures. To appear in the proceedings of 9th
Adriatic Meeting, Dubrovnik, Croatia, 4 - 14 September 2003. Added reference
into reference no.
Heterotic compactifications on SU(2)-structure backgrounds
In this paper we study the reduction of heterotic string theory on
SU(2)-structure backgrounds. We compute the bosonic low-energy gauged N=2
supergravity specified by the Killing vectors corresponding to the gauged
isometries. We check that the obtained Lagrangian is consistent with the one of
N=2 local supersymmetry. We also determine the Killing prepotentials.Comment: reference added, corrected typos and some factor
Exploring passenger rail markets using new station catchment size and shape metrics
This paper presents a novel spatial market segmentation method to determine key user groups of a train station (such as gender, age and access mode), based on the size and shape of the station catchment area of each group. Two new indicesâarea ratio and composite ratioâare developed to quantify the importance of user groups for a train station. This method is applied to identify key user groups at seven train stations in Perth, Western Australia. The study offers a new way to explore the travel behaviour of train users and provides insights for rail transport planning and marketing
- âŠ