bluuebunny/crossref_metadata_2025_split huggingface dataset:
An explicit transient algorithm for predicting incompressible viscous flows in Arbitrary Geometry
Authors: Mukhopadhyay A. , Sundararajan T. , Biswas G. 
Published: November 2005

AbstractA numerical method for predicting viscous flows in complex geometries has been presented. Integral mass and momentum conservation equations are deploved and these are discretized into algebraic form through numerical quadrature. The physical domain is divided into a number of non‐orthogonal control volumes which are isoparametrically mapped on to standard rectangular cells. Numerical integration for unsteady mementum equations is performed over such non‐orthogonal cells. The explicitly advanced velocity components obtained from unsteady momentum equations may not necessarily satisfy the mass conservation condition in each cell. Compliance of the mass conservation equation and the consequent evolution of correct pressure distribution are accomplished through an iterative correction of pressure and velocity till divergence‐free condition is obtained in each cell. The algorithm is applied on a few test problems, namely, lid‐driven square and oblique cavities, developing flow in a rectangular channel and flow over square and circular cylinders placed in rectangular channels. The results exhibit good accuracy and justify the applicability of the algorithm.This Explicit Transient Algorithm for Flows in Arbitrary Geometry is given a generic name EXTRAFLAG.
Optimal design of spiral casing tongue and wicket gate angle by decomposition method
Authors: Mrša Z. 
Published: November 2005

AbstractA method of optimal design of Francis turbine tongue and wicket gate angle for given spiral casing is proposed. The potential flow in the doubly connected domain is decomposed into basic and circulation flows. The intensity of circulation is then calculated by the least‐squares method minimizing the error function equal to the sum of squares of differences between given and calculated circumferential velocities in the outflow boundary nodes. It is shown that the error function has a sharp minimum, which qualifies the proposed method as well defined. For given numerical example, the variations in the outflow velocity angles are much smaller for optimal than for already used non‐optimal design. A finite element method is used, with originally developed pre‐ and post‐processor and frontal solver suited for personal computers.
Simulation of vortex shedding including blockage by the random‐vortex and other methods
Authors: Stansby P. K. , Slaouti A. 
Published: November 2005

AbstractConverged simulations of vortex shedding from a circular cylinder at a Reynolds number of 100 have been computed by the random‐vortex method incorporating the influence of blockage. The results are compared with converged finite‐element and spectral methods and close agreement for Strouhal number is obtained. Forces are, however, in less close agreement, particularly the fluctuating lift force. Strouhal numbers from simulations with zero blockage for Reynolds numbers between 60 and 180 are seen to be in very close agreement with experiments which are said to be effectively two‐dimensional. In this range the Strouhal number changes from 0·135 to 0·191. There are no corresponding experimental measurements for force.
Computation of free surface waves around an arbitrary body by a Navier‐Stokes solver using the psuedocompressibility technique
Authors: Liu H. , Ikehata M. 
Published: November 2005

AbstractA Navier‐Stokes equation solver is developed for computing free surface wave and viscous flow around an arbitrary body, in which a free surface model is introduced into the pseudocompressibility solution. The governing equations are classified in a vectorial form, with primitive variables, and a block diagonal system is generated by the discretization of an implicit factorization method. A moving grid system fitted to both the free surface and body surface is generated by an effective cubic spline fitting technique. Two zero‐equation turbulence models, namely the Cebeci‐Smith model and the Baldwin‐Lomax model, are used for turbulent calculations. Numerical simulations are carried out for the free surface viscous flows generated by a submerged hydrofoil and a ship model. Computed results are in reasonable agreement with measurements.
Numerical simulation method for viscoelastic flows with free surfaces—fringe element generation method
Authors: Sato Toru , Richardson Stephen M. 
Published: November 2005

AbstractTo simulate filling flow in injection moulding for viscoelastic fluids, a numerical method, based on a finite element method and a finite volume method, has been developed for incompressible isothermal viscoelastic flow with moving free surfaces. The advantages of this method are, first, good applicability to arbitrarily shaped mould geometries and, second, accurate treatment for boundary conditions on the free surface. Typical filling flows are simulated, namely filling flow into a 1:4 expansion cavity with and without an obstacle. Numerical results predict the position of weld lines and air‐traps. The method also indicates the effects of elongational flow on molecular orientation.
A characteristic‐based method for incompressible flows
Authors: Drikakis D. , Govatsos P. A. , Papantonis D. E. 
Published: November 2005

AbstractA new characteristic‐based method for the solution of the 2D laminar incompressible Navier‐Stokes equations is presented. For coupling the continuity and momentum equations, the artificial compressibility formulation is employed. The primitives variables (pressure and velocity components) are defined as functions of their values on the characteristics. The primitives variables on the characteristics are calculated by an upwind diffencing scheme based on the sign of the local eigenvalue of the Jacobian matrix of the convective fluxes. The upwind scheme uses interpolation formulae of third‐order accuracy. The time discretization is obtained by the explicit Runge–Kutta method. Validation of the characteristic‐based method is performed on two different cases: the flow in a simple cascade and the flow over a backwardfacing step.
Numerical investigation of dynamic stall of an oscillating aerofoil
Authors: Guo W. H. , Fu D. X. , Ma Y. W. 
Published: November 2005

AbstractThe flow structure around an NACA 0012 aerofoil oscillating in pitch around the quarter‐chord is numerically investigated by solving the two‐dimensional compressible N–S equations using a special matrix‐splitting scheme. This scheme is of second‐order accuracy in time and space and is computationally more efficient than the conventional flux‐splitting scheme. A ‘rigid’ C‐grid with 149 × 51 points is used for the computation of unsteady flow. The freestream Mach number varies from 0.2 to 06 and the Reynolds number from 5000 to 20,000. The reduced frequency equals 0.25–0.5. The basic flow structure of dynamic stall is described and the Reynolds number effect on dynamic stall is briefly discussed. The influence of the compressibility on dynamic stall is analysed in detail. Numerical results show that there is a significant influence of the compressibility on the formation and convection of the dynamic stall vortex. There is a certain influence of the Reynolds number on the flow structure. The average convection velocity of the dynamic stall vortex is approximately 0.348 times the freestream velocity.
A semi‐collocated ocean model based on the SOMS approach
Authors: Dietrich David E. , Ko Dong‐Shan 
Published: November 2005

AbstractIn application to the Gulf of Mexico (GOM), a new DieCAST ocean model, which uses a modified Arakawa ‘a’ grid, and the SOMS model, which uses an Arakawa ‘c’ grid, give remarkably similar results. The new model avoids ‘null space’ problems of the standard ‘a’ grid approach by first using fourth‐order interpolations to a ‘c’ grid advection velocity, then applying incompressibility to the result. Accuracy is further improved by using fourth‐order pressure gradient approximations at ‘a’ grid locations. Incompressibility with general geometry is satisfied efficiently by a fast‐converging iteration with a regular gteometry elliptic solver. Results are compared with satellite‐measured r.m.s. sea surface elevation anomaly and detailed front structures, climatological mean thermocline and empirical orthogonal functions and other observations.
Parallel fluid dynamics computations in aerospace applications
Authors: Aliabadi S. K. , Tezduyar T. E. 
Published: November 2005

AbstractMassively parallel finite element computations of the compressible Euler and Navier‐Stokes equations using parallel supercomputers are presented. The finite element formulations are based on the conservation variables and the streamline‐upwind/Petrov‐Galerkin (SUPG) stabilization method is used to prevent potential numerial oscillations due to dominant advection terms. These computations are based on both implicit and explicit methods and their parallel implementation assumes that the mesh is unstructured. The implicit computations are based on iterative strategies. Large‐scale 3D problems are solved using a matrix‐free iteration technique which reduces the memory requirements significantly. The flow problems we consider typically come from aerospace applications, including those in 3D and those involving moving boundaries interacting with boundary layers and shocks. Problems with fixed boundaries are solved using a semidiscrete formulation and the ones involving moving boundaries are solved using the deformable‐spatial‐domain/stabilized‐space‐time (DSD/SST) formulation.
A case study in parallel computation: Viscous flow around an ONERA M6 wing
Authors: Johan Zdeněk , Mathur Kapil K. , Johnsson S. Lennart , Hughes Thomas J. R. 
Published: November 2005

AbstractWe examine the solution of a practical engineering problem on a parallel computer. The problem involves the steady laminar viscous flow about an ONERA M6 wing and the computer is a 64‐processing‐node Connection Machine CM‐5E. We show that efficient domain decomposition procedures lead to a balanced load on the processors and low communication times. The net result is that solutions can be attained in roughly 20 min elapsed time for a 48,011‐node, 266,566‐element unstructured mesh. We conclude that this is sufficiently fast to support the design process.
Phenotypic and functional heterogeneity of GFAP‐expressing cells in vitro: Differential expression of LeX/CD15 by GFAP‐expressing multipotent neural stem cells and non‐neurogenic astrocytes
Authors: Imura Tetsuya , Nakano Ichiro , Kornblum Harley I. , Sofroniew Michael V. 
Published: November 2005

AbstractRecent findings show that the predominant multipotent neural stem cells (NSCs) isolated from postnatal and adult mouse brain express glial fibrillary acid protein (GFAP), a protein commonly associated with astrocytes, and that primary astrocyte cultures can contain GFAP‐expressing cells that act as multipotent NSCs when transferred to neurogenic conditions. The relationship of GFAP‐expressing NSCs to GFAP‐expressing astrocytes is unclear, but has important implications. We compared the phenotype and neurogenic potential of GFAP‐expressing cells derived from different CNS regions and maintained in vitro under different conditions. Multiple labeling immunohistochemistry revealed that both primary astrocyte cultures and adherent neurogenic cultures derived from postnatal or adult periventricular tissue contained subpopulations of GFAP‐expressing cells that co‐expressed nestin and LeX/CD15, two molecules associated with NSCs. In contrast, GFAP‐expressing cells in similar cultures prepared from adult cerebral cortex did not express detectable levels of LeX/CD15, and exhibited no neurogenic potential. Fluorescence‐activated cell sorting (FACS) of both primary astrocyte cultures and adherent neurogenic cultures for LeX/CD15 showed that GFAP‐expressing cells competent to act as multipotent NSCs were concentrated in the LeX‐positive fraction. Using neurosphere assays and a transgenic ablation strategy, we confirmed that the predominant NSCs in primary astrocyte and adherent neurogenic cultures were GFAP‐expressing cells. These findings demonstrate that GFAP‐expressing cells derived from postnatal and adult forebrain are heterogeneous in both molecular phenotype and neurogenic potential in vitro, and that this heterogeneity exists before exposure to neurogenic conditions. The findings provide evidence that GFAP‐expressing NSCs are phenotypically and functionally distinct from non‐neurogenic astrocytes. © 2005 Wiley‐Liss, Inc.
Albumin induces cellular fibrosis by upregulating transforming growth factor‐beta ligand and its receptors in renal distal tubule cells
Authors: Liu Hung‐Chang , Liao Tung‐Nan , Lee Tao‐Chen , Chuang Lea‐Yea , Guh Jinn‐Yuh , Liu Shu‐Fen , Hu Min‐Shou , Yang Ya‐Lin , Lin Shyh‐Horng , Hung Min‐Yuan , Huang Jau‐Shyang , Hung Tsung‐Jen , Chen Chun‐Da , Chiang Tai‐An , Chan Jun‐Yu , Chen Sen‐Yi , Yang Yu‐Lin 
Published: November 2005

AbstractAlbuminuria is indicative of nephropathy. However, little literature has focused on the role of albumin in renal distal tubule fibrosis. We used a well‐defined distal tubule cell, Madin‐Darby Canine Kidney (MDCK). Proliferation and cytotoxicity were examined. The conditioned supernatant was collected and subjected to ELISA assay for detection of fibronectin and TGF‐β1. Reverse transcription‐PCR and Western blot assay were performed to evaluate the expression of mRNA and protein of two types of TGF‐β receptors (TbetaR). Flow cytometry assay and phosphotyrosine (pY)‐specific antibodies were used to assay the phosphorylation status of TbetaR. We showed that albumin dose dependently (0, 0.1, 1, or 10 mg/ml) inhibited cellular growth in MDCK cells without inducing cellular cytoxicity. In addition, albumin significantly upregulated the secretion of both fibronectin and TGF‐β1 at dose over 1 mg/ml. Moreover, 24 h pretreatment of albumin significantly enhanced exogenous TGF‐β1‐induced secretion of fibronectin. These observations were reminiscent of the implications of TbetaR since TbetaR appears to correlate with the susceptibility of cellular fibrosis. We found that albumin significantly increased protein levels of type I TbetaR (TbetaRI) instead of type II receptors (TbetaRII). In addition, phosphorylation level of TbetaRII of both pY259 and pY424 was significantly enhanced instead of pY336. The novel observation indicates that extreme dose of albumin upregulates TGF‐β autocrine loop by upregulating TGF‐β1, TbetaRI, and the receptor kinase activity of TbetaRII by inducing tyrosine phosphorylation on key amino residue of TbetaRII in renal distal tubule cells. These combinational effects might contribute to the pathogenesis of renal fibrosis. J. Cell. Biochem. 97: 956–968, 2006. © 2005 Wiley‐Liss, Inc.
Prevalent mutations in prostate cancer
Authors: Dong Jin‐Tang 
Published: November 2005

AbstractQuantitative and structural genetic alterations cause the development and progression of prostate cancer. A number of genes have been implicated in prostate cancer by genetic alterations and functional consequences of the genetic alterations. These include the ELAC2 (HPC2), MSR1, and RNASEL (HPC1) genes that have germline mutations in familial prostate cancer; AR, ATBF1, EPHB2 (ERK), KLF6, mitochondria DNA, p53, PTEN, and RAS that have somatic mutations in sporadic prostate cancer; AR, BRCA1, BRCA2, CHEK2 (RAD53), CYP17, CYP1B1, CYP3A4, GSTM1, GSTP1, GSTT1, PON1, SRD5A2, and VDR that have germline genetic variants associated with either hereditary and/or sporadic prostate cancer; and ANXA7 (ANX7), KLF5, NKX3‐1 (NKX3.1), CDKN1B (p27), and MYC that have genomic copy number changes affecting gene function. More genes relevant to prostate cancer remain to be identified in each of these gene groups. For the genes that have been identified, most need additional genetic, functional, and/or biochemical examination. Identification and characterization of these genes will be a key step for improving the detection and treatment of prostate cancer. © 2005 Wiley‐Liss, Inc.
Lymphocyte enhancer‐binding factor 1 (Lef1) inhibits terminal differentiation of osteoblasts
Authors: Kahler Rachel A. , Galindo Mario , Lian Jane , Stein Gary S. , van Wijnen Andre J. , Westendorf Jennifer J. 
Published: November 2005

AbstractLef1 is a transcriptional regulator of the Wnt/β‐catenin signaling cascade. Wnts directly augment bone formation and osteoblast differentiation from mesenchymal stem cells by receptor‐mediated pathways involving Lrp5 and Frizzled. We previously reported that Lef1 represses Runx2‐dependent activation of the late osteoblast differentiation gene, osteocalcin. Lef1 is expressed in preosteoblasts but is undetectable in fully differentiated osteoblasts. To determine if downregulation of Lef1 is necessary for osteoblast maturation, we constitutively overexpressed Lef1 in MC3T3‐E1 preosteoblasts. Lef1‐overexpressing cells produced alkaline phosphatase (ALP) and osteocalcin later, and at lower levels than control cells. Moreover, the extracellular matrices of Lef1‐overexpressing cell cultures never mineralized. To further examine the role of Lef1 in osteoblasts, we suppressed Lef1 expression in MC3T3‐E1 cells by RNA interference. Transient expression of a Lef1 shRNA efficiently reduced murine Lef1 levels and transcriptional activity. Stable suppression of Lef1 in MC3T3 preosteoblasts did not affect proliferation or Runx2 levels; however, ALP production and matrix mineralization were accelerated by 3–4 days. Gene chip analyses identified 14 genes that are differentially regulated in Lef1‐suppressed cells. These data outline a role for Lef1 in delaying osteoblast maturation and suggest that Lef1 controls the expression of multiple genes in osteoblasts. J. Cell. Biochem. 97: 969–983, 2006. © 2005 Wiley‐Liss, Inc.
Innovative ways of making aid effective in Ghana: tied aid versus direct budgetary support
Authors: Quartey Peter 
Published: November 2005

AbstractIn 2003, the government of Ghana and its development partners agreed on an aid package dubbed the multi‐donor budgetary support (MDBS), which would ensure continuous flow of aid to finance the government's poverty related expenditures. This paper examines the MDBS, specifically focusing on how it overcomes the problems of tied aid and other project support. It concludes that the MDBS is innovative and could work in Ghana, but it would need trust and a well‐designed, coordinated effort on the part of the government of Ghana and its development partners. Second, its effectiveness would depend crucially on measures to help reduce the debt burden, so that the government would not be compelled to use aid inflows to service its debt. Finally, the MDBS could be more effective if it did not have to operate alongside other project support. Copyright © 2005 John Wiley & Sons, Ltd.
Mutant human tumor suppressor p53 modulates the activation of mitogen‐activated protein kinase and nuclear factor‐κB, but not c‐Jun N‐terminal kinase and activated protein‐1
Authors: Gulati Anthony P. , Yang Yang‐Ming , Harter David , Mukhopadhyay Asok , Aggarwal Bharat A. , Benzil Deborah L. , Whysner John , Albino Anthony P. , Murali Raj , Jhanwar‐Uniyal Meena 
Published: November 2005

AbstractThe roles of the mitogen‐activated kinase protein (MAPK) pathway, nuclear factor‐kappa B (NF‐κB), and activator protein‐1 (AP‐1) in cellular responses to growth factors and mitogen are well established. However, the manner by which these proliferative pathways are affected by the tumor suppressor protein p53 is not fully understood. We report here the results of an investigation of the status of p53 on two human melanoma cell lines with wild‐type p53 (SK‐Mel‐186) or mutant p53 (SK‐Mel‐110). The basal levels of the activated extracellular‐signal regulated kinases 1 and 2 (ERK1/2) were high in cells with wild‐type p53, but low in cells with mutant p53. The 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA)‐induced activation of ERK1/2 through the phosphorylation of threonine and tyrosine at 202 and 204, respectively, was demonstrated in both cell lines, however, in a discrete manner. TPA‐induced activation of ERK1/2 was sustained in wild‐type p53 cells, while only a transient activation was seen in mutant p53 cells. Inhibition of MAPK kinase (MEK), an upstream kinase, by U0126, blocked TPA‐induced activation of ERK1/2 in wild‐type p53 cells and in mutant p53 cells. Treatment of wild‐type p53 (SK‐Mel 186) cells with small interfering RNA (siRNA) of p53 displayed a transient induction of activation of ERK1/2 following TPA treatment, indicating that p53 has a role in the regulation of the activation of ERK1/2. NF‐κB activity decreased significantly in cells with wild‐type p53, while enhanced NF‐κB activity was evident in cells with mutant p53. The expression of either wild‐type or mutant p53 had a similar effect on TPA‐induced Jun N‐terminal kinase (JNK) activation, indicating specificity for the ERK pathway. Similarly, AP‐1 binding activity showed a transient variation in both cell lines after TPA treatment but with different kinetics. These observations suggest that both wild‐type and mutant p53 can modulate the activation pathways for ERK1/2, and NF‐κB distinctively, while modulating the pathways of JNK and AP‐1 similarly. These differences may influence cellular processes such as proliferation, differentiation, and apoptosis. © 2005 Wiley‐Liss, Inc.
On non‐stationary flows of incompressible asymmetric fluids
Authors: Łukaszewicz Grzegorz 
Published: November 2005

AbstractWe consider an initial boundary value problem for the system of equations describing non‐stationary flows of incompressible asymmetric fluids. We prove the existence of a local in time, weak solution of the problem in the case when the initial density is not separated from zero by a positive constant.
Modelling and solving fixed‐bed adsorption
Authors: Aracil J. , Casillas J. L. , Martínez M. , López‐Gómez J. 
Published: November 2005

AbstractIn this paper we develop a mathematical model for packed‐bed adsorption of a single component, directed toward the purification of β‐lactamic antibiotics. The model describes the removal of sorbates from an aqueous stream entering a bed packed with spherical sorbent particles. Then, assuming that the adsorption isotherm is linear, an exact solution for this model is found.
Relative entropy maximization and directed diffusion equations
Authors: Illner Reinhard , Neunzert Helmut 
Published: November 2005

AbstractMotivated by the concept of maximum entropy methods in signal and image processing, we introduce and discuss a class of ‘directed diffusion equations’ with suitable boundary conditions. The paradigmatic ‘directed diffusion equation’ is
equation image
The relative entropy \documentclass{article}\pagestyle{empty}\begin{document}$ Sb[f](t): = - \int_\Omega {f(t,x)} \;\ln \;(f(t,x)/b(x))dx $\end{document} is rapidly increasing along solution trajectories of (i). This suggests that solving (i) will yield efficient procedures for entropy maximization. We also discuss the asymptotic behavior of solutions of (i)—this is readily done because (i) has a large family of Ljapunov functionals.
Evolution of a microstructure: A convexified model
Authors: Roubíček Tomáš 
Published: November 2005

AbstractIt is known that, in a steady‐state case, the variational principle of minimal non‐convex potential energy creates a microstructure. This paper tries to formulate evolution of such microstructure on a basis of an energy variational principle (of the Hamilton type) involving a kinetic and a Rayleigh dissipative energies with the generalized impulse respecting a ‘convexified’ geometry. The existence of a solution is proved, using an approximation by a semi‐discretization in time. Some quantitative properties are investigated, too.