Natural Convection in a Vertical Microannulus with Superhydrophobic Slip and Temperature Jump

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Darcy-Brinkman Flow Through a Corrugated Channel

A perturbation analysis is carried out to the second order to give effective equations for Darcy-Brinkman flow through a porous channel with slightly corrugated walls. The flow is either parallel or normal to the corrugations, and the corrugations of the two walls are either in phase or half-period out of phase. The present study is based on the assumptions that the corrugations are periodic sinusoidal waves of small amplitude, and the channel is filled with a sparse porous medium so that the flow can be described by the Darcy-Brinkman model, which approaches the Darcian or Stokes flow limits for small or large permeability of the medium. The Reynolds number is also assumed to be so low that the nonlinear inertia can be ignored. The effects of the corrugations on the flow are examined, quantitatively and qualitatively, as functions of the flow direction, the phase difference, and the wavelength of the corrugations, as well as the permeability of the channel. It is found that the corrugations will have greater effects when it is nearer the Stokes' flow limit than the Darcian flow limit, and when the wavelength is shorter. For the same wavelength and phase difference, cross flow is more affected than longitudinal flow by the corrugations. Opposite effects can result from 180° out-of-phase corrugations, depending on the flow direction, the wavelength, as well as the permeability. © The Author(s) 2010.published_or_final_versionSpringer Open Choice, 31 May 201

Instruments: HRC

HRC operations continue smoothly with no major problems, anomalies, or interruptions. Routine monitoring observations show no significant charge extraction from the detectors. There may be some evidence of a decrease in the low energy (below 400 eV) QE of the HRC-S, probably indicative of the chemical evolution of the CsI photocathode. This is being monitored by the CXC Cal team and the HRC instrument team, but this phenomenon currently is not significant for scientific observations. There has been no significant change in the HRC-I quantum efficiency during the past year. One HRC observation was made using one of the shutters during the past year, an HRC+LETG observation of the Crab Nebula. The shutter was used to block the zeroth order image in order to reduce the overall instrument rate from this bright source below the telemetry limit. There were some anomalies in inserting and withdrawing the shutter in the past. Overall another quiet year from an HRC perspective. A wide variety of scientific investigations have been carried out over the past year with the HRC instruments. This year we highlight an HRC-I observation of the Mouse nebula, a pulsar wind nebula, demonstrating the HRC's imaging and timing capabilities.published_or_final_versio

Slip flow due to a stretching cylinder

The slip flow due to a stretching cylinder is studied. A similarity transform reduces the NavierStokes equations to a set of non-linear ordinary differential equations. Asymptotic solutions for large Reynolds number and small slip show the problem can be related to the existing two-dimensional stretching cases. Due to algebraic decay, the equations are further transformed through a compressed variable, and then integrated numerically. It is found that slip greatly reduces the magnitudes of the velocities and the shear stress. © 2011 Elsevier Ltd.postprin

Natural convection for slip flow in a vertical polygonal duct

Free convection with velocity slip and temperature jump in a vertical polygonal duct with a heated circular core is semianalytically solved by the methods of eigenfunction expansion and point match. The conditions of the core wall being at uniform wall temperature or uniform heat flux are considered. It is shown that the temperature and flowfields can be very different from those without the velocity slip and temperature jump. The optimum core radius and the corresponding maximum flow rate are numerically determined for some values of the slip length, temperature jump coefficient, and the number of sides of the polygon. Read More: http://arc.aiaa.org/doi/abs/10.2514/1.T4406postprin

Clinical Potentials of Cardiomyocytes Derived from Patient-Specific Induced Pluripotent Stem Cells

The lack of appropriate human cardiomyocyte-based experimental platform has largely hindered the study of cardiac diseases and the development of therapeutic strategies. To date, somatic cells isolated from human subjects can be reprogramed into induced pluripotent stem cells (iPSCs) and subsequently differentiated into functional cardiomyocytes. This powerful reprogramming technology provides a novel in vitro human cell-based platform for the study of human hereditary cardiac disorders. The clinical potential of using iPSCs derived from patients with inherited cardiac disorders for therapeutic studies have been increasingly highlighted. In this review, the standard procedures for generating patient-specific iPSCs and the latest commonly used cardiac differentiation protocols will be outlined. Furthermore, the progress and limitations of current applications of iPSCs and iPSCs-derived cardiomyocytes in cell replacement therapy, disease modeling, drug-testing and toxicology studies will be discussed in detail.published_or_final_versio

Density estimates on composite polynomials

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On the effects of liquid-gas interfacial shear on slip flow through a parallel-plate channel with superhydrophobic grooved walls

Comparisons between slip lengths predicted by a liquid-gas coupled model and that by an idealized zero-gas-shear model are presented in this paper. The problem under consideration is pressure-driven flow of a liquid through a plane channel bounded by two superhydrophobic walls which are patterned with longitudinal or transverse gas-filled grooves. Effective slip arises from lubrication on the liquid-gas interface and intrinsic slippage on the solid phase of the wall. In the mathematical models, the velocities are analytically expressed in terms of eigenfunction series expansions, where the unknown coefficients are determined by the matching of velocities and shear stresses on the liquid-gas interface. Results are generated to show the effects due to small but finite gas viscosity on the effective slip lengths as functions of the channel height, the depth of grooves, the gas area fraction of the wall, and intrinsic slippage of the solid phase. Conditions under which even a gas/liquid viscosity ratio as small as 0.01 may have appreciable effects on the slip lengths are discussed. © 2010 American Institute of Physics.published_or_final_versio

Dosimetric evaluation of the interplay between LINAC movement and tumor motion in respiratory gated VMAT of lung cancer

This journal suppl. entitled: Proceedings of the American Society for Radiation Oncology 54th Annual MeetingConference Theme: Advancing Patient Care Through InnovationPURPOSE/OBJECTIVE(s): Respiratory gated radiation therapy of lung cancer helps to minimize the treated volume and hence treatment side effects. VMAT can reduce the treatment time while producing a highly conformed dose distribution. However, in gated VMAT delivery, the interplay effect between the LINAC movement (MLC and gantry) and tumor motion may result in undesirable hot and cold spots jeopardizing tumor coverage. In this study we investigated the possible dosimetric errors caused by the interplay between the tumor motion and the LINAC movement for gated VMAT lung cancer treatment. MATERIALS/METHODS: We studied 2 …published_or_final_versio

A prospective, assessor-blind evaluation of surgeon-performed transcutaneous laryngeal ultrasonography in vocal cord examination before and after thyroidectomy

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