1,310 research outputs found
The ALE-method with triangular elements: direct convection of integration point values
The arbitrary Lagrangian-Eulerian (ALE) finite element method is applied to the simulation of forming processes where material is highly deformed. Here, the split formulation is used: a Lagrangian step is done with an implicit finite element formulation, followed by an explicit (purely convective) Eulerian step. The purpose of this study is to investigate the Eulerian step for quadratic triangular elements. To solve the convection equation for integration point values, a new method inspired by Van Leer is constructed. The new method is based on direct convection of integration point values without intervention of nodal point values.\ud
The Molenkamp test and a so-called block test were executed to check the performance and stability of the convection scheme. From these tests it is concluded that the new convection scheme shows accurate results. The scheme is extended to an ALE-algorithm. An extrusion process was simulated to test the applicability of the scheme to engineering problems. It is concluded that direct convection of integration point values with the presented algorithm leads to accurate results and that it can be applied to ALE-simulation
The new modelling method in urban development : case study in Rotterdam
Land-use transition, energy consumption, and temperature fluctuation are the three dominant topics we have investigated in this research. In the last century, 38 heat waves occurred in Europe, of which eleven were after 1900 and six after 2000 (IPCC, 2007). Local-climate changes due to urbanization are epitomized by the urban heat island (UHI), which mainly focuses on the interaction of land use and temperature. However, energy is also an important issue when we investigate the sustainable urban development. This research detects correlations between land-use transition, energy consumption, and temperature fluctuation in the Rotterdam area from 1996 till now. We use a series of maps to illustrate the relationship of temperature fluctuation and energy consumption. These two variables are linked via land-use maps. From the data set, the spatial parameters are estimated that have a significant effect on the correlation between temperature fluctuation and energy consumption. Finally we draw conclusions on the Rotterdam 2050 city scenario, taking the found spatial parameters into consideration
The new modelling method in urban development : case study in Rotterdam
Land-use transition, energy consumption, and temperature fluctuation are the three dominant topics we have investigated in this research. In the last century, 38 heat waves occurred in Europe, of which eleven were after 1900 and six after 2000 (IPCC, 2007). Local-climate changes due to urbanization are epitomized by the urban heat island (UHI), which mainly focuses on the interaction of land use and temperature. However, energy is also an important issue when we investigate the sustainable urban development. This research detects correlations between land-use transition, energy consumption, and temperature fluctuation in the Rotterdam area from 1996 till now. We use a series of maps to illustrate the relationship of temperature fluctuation and energy consumption. These two variables are linked via land-use maps. From the data set, the spatial parameters are estimated that have a significant effect on the correlation between temperature fluctuation and energy consumption. Finally we draw conclusions on the Rotterdam 2050 city scenario, taking the found spatial parameters into consideration
Yukawa Deflected Gauge Mediation in Four Dimensions
We construct a four dimensional realization of a higher dimensional model,
Yukawa deflected gauge mediation, in which supersymmetry breaking is
communicated to the visible sector through both gauge and Yukawa interactions.
The reduction to four dimensions is achieved by `deconstructing' or
`latticizing' the extra dimension. Three sites (gauge groups) are sufficient to
reproduce the spectrum of the higher dimensional model. The characteristic
features of Yukawa deflected gauge mediation, in particular, alignment of
squarks and quarks, and a natural solution to the mu problem, carry over to the
deconstructed version of the model. We comment on the implications of our
results for a solution of the mu problem in the context of deconstructed
gaugino mediation.Comment: 11 pages, 1figur
Anti-inflammatory effect of low intensity ultrasound (LIUS) on complete Freund's adjuvant-induced arthritis synovium
SummaryObjectivesArthritis with intra-articular inflammation was accompanied by joint pain, swelling, and stiffness leading to significant functional impairment. Thus, regulation of joint inflammation is a good therapeutic approach for patients with arthritis. In this study, the effect of low intensity ultrasound (LIUS) applied to an adjuvant-induced arthritic rat model on the synovium was investigated.DesignSynovial inflammation was induced by complete Freund's adjuvant (CFA)-injection into the rat knee joint. LIUS (200 mW/cm2) was applied on the ipsilateral knee everyday for 10 min beginning 1 day after inflammation induction. The expression of proinflammatory factors and immunohistochemical staining pattern of the synovium were assessed.ResultsCFA induced an increase of the knee circumference that was significantly diminished by LIUS. Synovial membrane hyperplasia in the ipsilateral joint was also affected by LIUS. The inflammatory mediators, COX-1/2, IL-1β, and iNOS, but not TNF-α, in the synovial membrane were induced after 3 days, and they closely correlated with the degree of edema. In the synovial membrane, the expression of inflammatory mediators was reduced by LIUS. The chemoattractant chemokine receptor CCR5 also was involved. On immunohistochemical analysis, CFA caused increased infiltration of CD11b-positive cells in the synovium. After 3 days, neutrophils, myeloperoxidase (MPO)-positive cells filled the inflammatory core; later, monocytes and macrophages, ionized calcium binding adaptor molecule 1 (Iba1)-positive cells in the periphery infiltrated the core by day 5. LIUS markedly reduced CFA-induced inflammatory cells infiltration.ConclusionLIUS showed a potent anti-inflammatory effect in this animal arthritis model with reduced infiltration of inflammatory cells into the synovium
The flavor-changing bottom-strange quark production in the littlest Higgs model with T parity at the ILC
In the littlest Higgs model with T-parity (LHT) the mirror quarks induce the
special flavor structures and some new flavor-changing (FC) couplings which
could greatly enhance the production rates of the FC processes. We in this
paper study some bottom and anti-strange production processes in the LHT model
at the International Linear Collider (ILC), i.e.,
and . The results show that the production
rates of these processes are sizeable for the favorable values of the
parameters. Therefore, it is quite possible to test the LHT model or make some
constrains on the relevant parameters of the LHT through the detection of these
processes at the ILC.Comment: 12 pages, 8 figure
The Simplest Little Higgs
We show that the SU(3) little Higgs model has a region of parameter space in
which electroweak symmetry breaking is natural and in which corrections to
precision electroweak observables are sufficiently small. The model is anomaly
free, generates a Higgs mass near 150 GeV, and predicts new gauge bosons and
fermions at 1 TeV.Comment: 13 pages + appendix, typos corrected, version to appear in JHE
Gravity and Matter in Extra Dimensions
In this paper, we derive from the viewpoint of the effective 4D theory the
interaction terms between linearized gravity propagating in N>= 2 large extra
dimensions and matter propagating into one extra dimension. This generalizes
known results for the interactions between gravity and 4D matter in ADD-type
models. Although we assume that matter is described by an Universal Extra
Dimensions (UED) scenario (with all fields propagating into the fifth
dimension), we present our results in a general form that can be easily adapted
to various other scenarios of matter distribution. We then apply our results to
the UED model on a fat brane and consider some phenomenological applications.
Among these are the computation of the gravitational decay widths of the matter
KK excitations and the effect the width of the brane has on the interactions of
gravity with Standard Model particles. We also estimate the cross-section for
producing single KK excitations at colliders through KK number-violating
gravitational interaction.Comment: 21 pages, 6 figures, Late
Anomalous Dynamics of Forced Translocation
We consider the passage of long polymers of length N through a hole in a
membrane. If the process is slow, it is in principle possible to focus on the
dynamics of the number of monomers s on one side of the membrane, assuming that
the two segments are in equilibrium. The dynamics of s(t) in such a limit would
be diffusive, with a mean translocation time scaling as N^2 in the absence of a
force, and proportional to N when a force is applied. We demonstrate that the
assumption of equilibrium must break down for sufficiently long polymers (more
easily when forced), and provide lower bounds for the translocation time by
comparison to unimpeded motion of the polymer. These lower bounds exceed the
time scales calculated on the basis of equilibrium, and point to anomalous
(sub-diffusive) character of translocation dynamics. This is explicitly
verified by numerical simulations of the unforced translocation of a
self-avoiding polymer. Forced translocation times are shown to strongly depend
on the method by which the force is applied. In particular, pulling the polymer
by the end leads to much longer times than when a chemical potential difference
is applied across the membrane. The bounds in these cases grow as N^2 and
N^{1+\nu}, respectively, where \nu is the exponent that relates the scaling of
the radius of gyration to N. Our simulations demonstrate that the actual
translocation times scale in the same manner as the bounds, although influenced
by strong finite size effects which persist even for the longest polymers that
we considered (N=512).Comment: 13 pages, RevTeX4, 16 eps figure
FCNC Top Quark Decays in Extra Dimensions
The flavor changing neutral top quark decay t -> c X is computed, where X is
a neutral standard model particle, in a extended model with a single extra
dimension. The cases for the photon, X= \gammaR_\xi gauge. We find that
the branching ratios can be enhanced by the dynamics originated in the extra
dimension. In the limit where 1/R >> ->, we have found Br(t -> c \gamma) \simeq
10^{-10} for 1/R = 0.5 TeV. For the decay t -> c H, we have found Br(t -> cH)
\simeq 10^{-10} for a low Higgs mass value. The branching ratios go to zero
when 1/R -> \infty.Comment: Accepted to be published in the Europ. Phys. Jour. C; 16 pages, 2
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