1,437 research outputs found
Inclined bottom boundary condition for the mild-slope equation
A finite element method is one of the most effective methods to analyze hydrodynamic behaviors in the coastal zone because it can be applied to irregular and complex geometry. However, it is not easy to treat the boundary condition properly under the condition of vertically inclined boundary. In this study, a numerical method for treatment of inclined bottom boundary in the finite element method is introduced. The mild-slope equation is used as a governing equation. Comparison with an analytical solution shows the validity of the present method
Fire resistance performance of submerged floating tunnel under various fire conditions
Submerged Floating Tunnels (SFT) were researched by countries had many island as Norway, Italy,\ud
China, and Japan. Several sites were examined in China and Norway. Most of them investigated about seismic, dynamic,\ud
and collision performance. However, present researches lack to apply the construction fields, therefore, additional\ud
researches need. Fire resistance performance of the SFT is important one of the various researches. If fire break out in\ud
SFT, it is damaged by thermal loads. The damage of the SFT varies by type of fire. Structure of the SFT is able to\ud
collapse partially by fire scale and fire exposure time. For this reason, fire resistance design of the SFT must be\ud
suggested. Fire resistance performance of SFT could be investigating for fire resistance design of SFT. Fire condition\ud
could be expressed fire curves which are suggested by fire scale and fire exposure time. In this paper, temperature\ud
distributions of the SFT were investigated through FE analysis under various fire conditions. Heat transfer analysis was\ud
applied to investigate conduction of heat by fire. And there was to draw the biggest influence fire condition to the SFT\ud
from FE analysis results. Also, preliminary study was performed for fire resistance design
Bending strength analysis of steel-composite submerged floating tunnels
A submerged floating tunnel (SFT) must have enough strength to resist to various external loadings such\ud
as bending, torsion, tension, and compression. The expected main deformation of SFT is caused by bending moment.\ud
And this bending moment makes tensile stress and compression stress on the wall of SFT. Thus, bending moment is a\ud
main affecting factor on the safety of SFT. Until now, a reinforced concrete tunnel was suggested for SFT by other\ud
researchers. In this study, an internally confined hollow reinforced concrete tunnel and a double skinned composite\ud
tubular tunnel were proposed. And their bending strengths were studied and compared with that of a reinforced concrete\ud
tunnel. The analysis results showed the proposed SFT structures had enough strength to guarantee safety
Effects of Varying the Three-Body Molecular Hydrogen Formation Rate in Primordial Star Formation
The transformation of atomic hydrogen to molecular hydrogen through
three-body reactions is a crucial stage in the collapse of primordial,
metal-free halos, where the first generation of stars (Population III stars) in
the Universe are formed. However, in the published literature, the rate
coefficient for this reaction is uncertain by nearly an order of magnitude. We
report on the results of both adaptive mesh refinement (AMR) and smoothed
particle hydrodynamics (SPH) simulations of the collapse of metal-free halos as
a function of the value of this rate coefficient. For each simulation method,
we have simulated a single halo three times, using three different values of
the rate coefficient. We find that while variation between halo realizations
may be greater than that caused by the three-body rate coefficient being used,
both the accretion physics onto Population III protostars as well as the
long-term stability of the disk and any potential fragmentation may depend
strongly on this rate coefficient.Comment: 29 pages, 7 figures; Accepted for publication in The Astrophysical
Journa
Evaluation of fermented whole crop wheat and barley feeding on growth performance, nutrient digestibility, faecal volatile fatty acid emission, blood constituents, and faecal microbiota in growing pigs
This study was conducted to determine the effects of feeding diets with fermented whole crop wheat (FWW) and fermented whole crop barley (FWB) on growth performance, nutrient digestibility, blood constituents, faecal volatile fatty acid (VFA) emission and faecal microbiota in growing pigs. A total of 200 growing pigs were randomly allotted to five treatments with eight replicates per treatment and five pigs per replicate. Dietary treatments consisted of i) CON (basal diet), ii) 0.5% FWW (CON + 0.5% fermented whole crop wheat), iii) 1.0% FWW (CON + 1.0% fermented whole crop wheat), iv) 0.5% FWB (CON + 0.5% fermented whole crop barley), and v) 1.0% FWB (CON + 1.0% fermented whole crop barley). The digestibility of total dietary fibre was significantly higher in pigs fed FWW diets. The faecal emissions of VFA of pigs fed the fermented treatments was increased significantly compared with CON. Concentrations of cortisol and triglyceride in blood of pigs fed 1.0% FWW were significantly lower than pigs fed CON diets. The pigs fed 1.0% FWB diets had a significantly decreased level of total cholesterol in blood compared with CON. In conclusion, the current results indicated that diets supplemented with FWW and FWB could increase faecal VFA emission and reduce concentration of triglyceride and cortisol, while 0.5% and 1.0% FWW had no negative effects on growth performance, and could increase digestibility of dietary fibre in growing pigs.Keywords: Dietary fibre, faecal short-chain fatty acid emissions, fermented feed, serum parameter, swin
T-Duality For String in Horava-Lifshitz Gravity
We continue our study of the Lorentz breaking string theories. These theories
are defined as string theory with modified Hamiltonian constraint which breaks
the Lorentz symmetry of target space-time. We analyze properties of this theory
in the target space-time that possesses isometry along one direction. We also
derive the T-duality rules for Lorentz breaking string theories and show that
they are the same as that of Buscher's T-duality for the relativistic strings.Comment: 17 pages, references adde
Jain States in a Matrix Theory of the Quantum Hall Effect
The U(N) Maxwell-Chern-Simons matrix gauge theory is proposed as an extension
of Susskind's noncommutative approach. The theory describes D0-branes,
nonrelativistic particles with matrix coordinates and gauge symmetry, that
realize a matrix generalization of the quantum Hall effect. Matrix ground
states obtained by suitable projections of higher Landau levels are found to be
in one-to-one correspondence with the expected Laughlin and Jain hierarchical
states. The Jain composite-fermion construction follows by gauge invariance via
the Gauss law constraint. In the limit of commuting, ``normal'' matrices the
theory reduces to eigenvalue coordinates that describe realistic electrons with
Calogero interaction. The Maxwell-Chern-Simons matrix theory improves earlier
noncommutative approaches and could provide another effective theory of the
fractional Hall effect.Comment: 35 pages, 3 figure
Effects of diet composition on growth performance and feed conversion efficiency in Alphitobius diaperinus larvae
Alphitobius diap]erinus has been recommended for mass-production as feed in a rearing facility because of its small size and short biological cycle. This study evaluated the effects of wheat bran and casein or their blend as insect diets on growth performance and feed conversion efficiency of A. diaperinus larvae in the laboratory. Casein and wheat bran were the protein and carbohydrate sources of choice, respectively, for diet preparation. Five experimental diet treatments to be tested were designed as follows: control (100% casein), T1 (75% casein +25% wheat bran), T2 (50% casein +50% wheat bran), T3 (25% casein +70% wheat bran), and T4 (100% wheat bran). A total of 150 new hatched larvae were randomly allotted to one of the five dietary treatments, with three replicates (10 hatched larvae per replicate). The standard colonies were composed of 10 hatched larvae, without distinction of sex, reared in a plastic box (14×8×5 cm) provided with aeration holes on the top. The evaluation of A. diaperinus larvae included growth performance and feed efficiency. Using casein and wheat bran blends for diet had a positive effect on weight gain and feed conversion ratio of A. diaperinus larvae, including an increase in average larval survival and average larval weight. Using casein and wheat blends (75% casein +25% wheat bran or 25% casein +70% wheat bran) as insect-rearing diet will allow effective utilization of the feed for poultry when using the edible portion of mealworms before reaching the pupae stage
Steering of a Bosonic Mode with a Double Quantum Dot
We investigate the transport and coherence properties of a double quantum dot
coupled to a single damped boson mode. Our numerically results reveal how the
properties of the boson distribution can be steered by altering parameters of
the electronic system such as the energy difference between the dots.
Quadrature amplitude variances and the Wigner function are employed to
illustrate how the state of the boson mode can be controlled by a stationary
electron current through the dots.Comment: 10 pages, 6 figures, to appear in Phys. Rev.
Particle Probe of Horava-Lifshitz Gravity
Kehagias-Sfetsos black hole in Ho\v{r}ava-Lifshitz gravity is probed through
particle geodesics. Gravitational force of KS black hole becomes weaker than
that of Schwarzschild around horizon and interior space. Particles can be
always scattered or trapped in new closed orbits, unlike those falling forever
in Schwarzschild black. The properties of null and timelike geodesics are
classified with values of coupling constants. The precession rates of the
orbits are evaluated. The time trajectories are also classified under different
values of coupling constants for both null and timelike geodesics. Physical
phenomena that may be observable are discussed.Comment: 10 pages, 8 figure
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