Fluid Models of Many-server Queues with Abandonment

We study many-server queues with abandonment in which customers have general service and patience time distributions. The dynamics of the system are modeled using measure- valued processes, to keep track of the residual service and patience times of each customer. Deterministic fluid models are established to provide first-order approximation for this model. The fluid model solution, which is proved to uniquely exists, serves as the fluid limit of the many-server queue, as the number of servers becomes large. Based on the fluid model solution, first-order approximations for various performance quantities are proposed

Frictional drag between non-equilibrium charged gases

The frictional drag force between separated but coupled two-dimensional electron gases of different temperatures is studied using the non-equilibrium Green function method based on the separation of center-of-mass and relative dynamics of electrons. As the mechanisms of producing the frictional force we include the direct Coulomb interaction, the interaction mediated via virtual and real TA and LA phonons, optic phonons, plasmons, and TA and LA phonon-electron collective modes. We found that, when the distance between the two electron gases is large, and at intermediate temperature where plasmons and collective modes play the most important role in the frictional drag, the possibility of having a temperature difference between two subsystems modifies greatly the transresistivity.Comment: 8figure

Performance of an objective fabric pilling evaluation method

In previous work, we established the principle of objective fabric pilling evaluation based on two-dimensional dual-tree complex wavelet transform (2DDTCWT) image reconstruction and non-linear classification using a neural network. This proof-of-principle work was performed using standard pilling test images. Here, we demonstrate the practical operation of the objective pilling evaluation method using a large set of real fabric pilling samples. We show that piling classification results from a trained multiple-layer perceptron neural network achieve a regression correlation of approximately 96% with the corresponding human expert pilling ratings.<br /

Strong Southward Transport Events Due to Typhoons in the Taiwan Strait

Transport through the Taiwan Strait under the influence of five typhoons was investigated using both buoy observations and numerical model simulations during the period of 27 August to 5 October 2005. The results show that the effects of typhoons on the Taiwan Strait and its adjacent sea area caused strong southward transport events in the Taiwan Strait, which changed the direction of the Taiwan Strait northward transport temporarily. Typhoon-generated local wind stress and/or along-strait water level gradient were the direct driving factors in these southward transport events. The numerical results show that the Coriolis force made a negative contribution to these events and the contribution of the along-strait momentum gradient was insignificant

Evaluation of the Dynamic Characteristics of AZ91D Crankcase Covers and Boxes

Dynamic tests are performed on similarly structured crankcase covers and boxes made of AZ91D magnesium and A380 aluminum alloys. The real vibration and noise control effect of an AZ91D magnesium alloy is evaluated, based on the behavior of the integral frequency response function, which is derived from the measured surface vibrations of the crankcase cover under operating conditions. The results indicate that crankcase covers and boxes made of AZ91D magnesium and A380 aluminum alloys with the same geometry possess similar normal characteristics. Both materials are interchangeable. However, the stiffness of AZ91D crankcase covers and boxes is poor. It is also difficult to obtain good engineering vibration and noise effects in the real structure due to an AZ91D high damping capacity. At the same excitation and frequency response at different structure characteristics, the measurement analysis of time-domain response indicates that methods to strengthen the crankcase box stiffness, such as embedding a main bearing steel sleeve, is favorable for improving the dynamic characteristics of an AZ91D crankcase box.Динамические испытания проводили на картерных крышках и поддонах аналогичной конструкции, изготовленных из магниевого AZ91D и алюминиевого А380 сплавов. Оценен эффект от применения магниевого сплава AZ91D для контроля реальной вибрации и шума на основании характера интегральной частотной функции отклика, полученной по результатам измерения поверхностной вибрации картерной крышки в рабочем режиме. Результаты показывают, что картерные крышки и поддоны, изготовленные из магниевого AZ91D и алюминиевого А380 сплавов, с одинаковыми геометрическими параметрами имеют аналогичные нормальные характеристики. Оба материала взаимозаменяемы. Однако картерная крышка и поддон из сплава AZ91D обладают низкой жесткостью. Достичь нормального технического уровня вибрации и шума в реальной конструкции также затруднительно, поскольку сплав AZ91D обладает высокой демпфирующей способностью. При одинаковом возбуждении и частотной характеристике конструкции с различными параметрами анализ измерения временной области показывает, что методы увеличения жесткости картерного поддона, например вмонтирование главного стального подшипника скольжения, способствуют улучшению динамических характеристик картерного поддона из сплава AZ91D

Dynamical Chiral Symmetry Breaking on the Light Front.II. The Nambu--Jona-Lasinio Model

An investigation of dynamical chiral symmetry breaking on the light front is made in the Nambu--Jona-Lasinio model with one flavor and N colors. Analysis of the model suffers from extraordinary complexity due to the existence of a "fermionic constraint," i.e., a constraint equation for the bad spinor component. However, to solve this constraint is of special importance. In classical theory, we can exactly solve it and then explicitly check the property of ``light-front chiral transformation.'' In quantum theory, we introduce a bilocal formulation to solve the fermionic constraint by the 1/N expansion. Systematic 1/N expansion of the fermion bilocal operator is realized by the boson expansion method. The leading (bilocal) fermionic constraint becomes a gap equation for a chiral condensate and thus if we choose a nontrivial solution of the gap equation, we are in the broken phase. As a result of the nonzero chiral condensate, we find unusual chiral transformation of fields and nonvanishing of the light-front chiral charge. A leading order eigenvalue equation for a single bosonic state is equivalent to a leading order fermion-antifermion bound-state equation. We analytically solve it for scalar and pseudoscalar mesons and obtain their light-cone wavefunctions and masses. All of the results are entirely consistent with those of our previous analysis on the chiral Yukawa model.Comment: 23 pages, REVTEX, the version to be published in Phys.Rev.D; Some clarifications in discussion of the LC wavefunctions adde

Subordination Pathways to Fractional Diffusion

The uncoupled Continuous Time Random Walk (CTRW) in one space-dimension and under power law regime is splitted into three distinct random walks: (rw_1), a random walk along the line of natural time, happening in operational time; (rw_2), a random walk along the line of space, happening in operational time;(rw_3), the inversion of (rw_1), namely a random walk along the line of operational time, happening in natural time. Via the general integral equation of CTRW and appropriate rescaling, the transition to the diffusion limit is carried out for each of these three random walks. Combining the limits of (rw_1) and (rw_2) we get the method of parametric subordination for generating particle paths, whereas combination of (rw_2) and (rw_3) yields the subordination integral for the sojourn probability density in space-time fractional diffusion.Comment: 20 pages, 4 figure

A polarized beam splitter using an anisotropic medium slab

The propagation of electromagnetic waves in the anisotropic medium with a single-sheeted hyperboloid dispersion relation is investigated. It is found that in such an anisotropic medium E- and H-polarized waves have the same dispersion relation, while E- and H-polarized waves exhibit opposite amphoteric refraction characteristics. E- (or H-) polarized waves are positively refracted whereas H- (or E-) polarized waves are negatively refracted at the interface associated with the anisotropic medium. By suitably using the properties of anomalous refraction in the anisotropic medium it is possible to realize a very simple and very efficient beam splitter to route the light. It is shown that the splitting angle and the splitting distance between E- and H- polarized beam is the function of anisotropic parameters, incident angle and slab thickness.Comment: 14 pages, 6 figure