bluuebunny/crossref_metadata_2025_split huggingface dataset:
Barchan‐shaped ripple marks in a wave flume
Authors: Endo Noritaka , Kubo Hidehito , Sunamura Tsuguo 
Published: January 2004

AbstractBarchans, isolated crescent‐shaped bedforms, are believed to be formed under almost unidirectional wind or water ﬂows and limited sand supply. The formation of barchan morphologies under the action of purely oscillatory wave motion has not yet been fully investigated. The present study attempted to form barchan topography in a wave ﬂume and to compare this with barchans in the ﬁeld. Barchan morphologies of ripple size, called the barchan ripples, were generated from a ﬂat bed by the action of waves. The horn width, the distance between horn tips, of the barchan ripples increased linearly with an increase in the total length, the overall length projected on the centre line of the barchan, with a coefﬁcient common to barchan dunes in deserts. The ratio of horn length to horn width of the barchan ripples was smaller than that of barchan dunes, but similar to that of subaqueous barchans in the ﬁeld. The longer the wave period was, the larger the ratio of the body length to horn width became. Most subaqueous barchans formed under waves (in the laboratory) and unidirectional ﬂows (in the ﬁeld) had blunter horns than subaerial barchans. The shape of the barchan ripples changed with wave period. The outer rim became rounder with increasing wave period. The relationship between the base area and the height of barchan morphologies seems to be linear, with a constant coefﬁcient for the scale from ripples to dunes. The barchan ripples showed a linear relationship between the height and the horn width, similar to that for barchan dunes. The migration speed of the barchan ripples was proportional to the cube of the ﬂow velocity and was inversely proportional to height. The same relation with a different value of the coefﬁcient was obtained for barchan dunes. Copyright © 2004 John Wiley & Sons, Ltd.
Sediment movement rates and processes on cinder cones in the maritime Subantarctic (Marion Island)
Authors: Holness Stephen Dale 
Published: January 2004

AbstractSediment transport in the scoria areas of Marion Island is primarily the result of needle‐ice‐induced frost creep associated with diurnal soil frost cycles. Clasts move most rapidly in ﬁne textured areas (532 mm a−1; SD 382), more slowly in stony areas (161 mm a−1; SD 179), and most slowly in blocky areas (26 mm a−1; SD 23). Movement rates increase with increasing frost susceptibility of sediments, slope angle and altitude. The heave of dowels indicates that frost heave is active in all the scoria areas examined. The depth of effective frost heave increases with increasing altitude, with frost heave being restricted to the upper 100 mm of the soil in low altitude areas (<200 m). The heave of 150 mm dowels at the higher altitude sites provides evidence for segregation ice formation at depths greater than those associated with needle ice and diurnal soil frost cycles. Vertical movement proﬁles show a concave downslope proﬁle, with sediment movement rates being most rapid at the soil surface and decreasing rapidly with depth. This proﬁle shape is typical of areas dominated by diurnal freeze–thaw cycles and needle ice. The capture of sediments moving downslope in troughs and the sampling of material lifted by needle ice, suggest that sediment transport by needle ice under present conditions is extremely effective. Observations suggest that although both ﬁne material and clasts are transported downslope, some preferential transport of clasts occurs.Experiment results and observations of soil frost processes suggest that frost creep associated with needle ice activity is the dominant slope process in the scoria areas of Marion Island. Other slope processes such as slopewash and debris ﬂows appear to play a relatively minor and localized role in sediment transport. It is suggested that needle ice activity is likely to be the dominant geomorphic agent in other areas of the Subantarctic with similar climatic characteristics to Marion Island. Copyright © 2004 John Wiley & Sons, Ltd.
Multipath parameters estimation with a reduced complexity unitary‐SAGE algorithm
Authors: Min Tan Chor , Beach Mark A. , Nix Andrew 
Published: January 2004

AbstractEstimating multipath parameters from multi‐dimensional measurement data using maximum‐likelihood methods can be a very time‐consuming process due to the iterative nature of these algorithms. Although the Space‐Alternating Generalized Expectation‐maximization (SAGE) algorithm has a higher convergence speed compared to the classical Expectation‐Maximization (EM) algorithm, it can still be computational‐intensive. Since most of the computations of the SAGE algorithm are concentrated in the maximization step (M‐step), we propose a new implementation of this algorithm, namely the Unitary‐SAGE (U‐SAGE) algorithm, where the entire M‐step in every iteration is evaluated in the real‐valued domain. This helps to reduce the processing time and memory requirements of the classical SAGE algorithm since all computations of the M‐step are performed using efficient matrix manipulation. Here, we present the general implementation of the U‐SAGE algorithm in the frequency domain when applied in both the element‐space (ES) and the newly developed beamspace (BS) domains. We show that the convergence characteristics and accuracy of the newly proposed U‐SAGE algorithm is similar to the classical SAGE algorithm, but with a significant reduction in overall computation time and memory usage. Copyright © 2004 AEI
Numerical simulation of turbulent free surface flow with two‐equation k–ε eddy‐viscosity models
Authors: Ferreira V. G. , Mangiavacchi N. , Tomé M. F. , Castelo A. , Cuminato J. A. , McKee S. 
Published: January 2004

AbstractThis paper presents a finite difference technique for solving incompressible turbulent free surface fluid flow problems. The closure of the time‐averaged Navier–Stokes equations is achieved by using the two‐equation eddy‐viscosity model: the high‐Reynolds k–ε (standard) model, with a time scale proposed by Durbin; and a low‐Reynolds number form of the standard k–ε model, similar to that proposed by Yang and Shih. In order to achieve an accurate discretization of the non‐linear terms, a second/third‐order upwinding technique is adopted. The computational method is validated by applying it to the flat plate boundary layer problem and to impinging jet flows. The method is then applied to a turbulent planar jet flow beneath and parallel to a free surface. Computations show that the high‐Reynolds k–ε model yields favourable predictions both of the zero‐pressure‐gradient turbulent boundary layer on a flat plate and jet impingement flows. However, the results using the low‐Reynolds number form of the k–ε model are somewhat unsatisfactory. Copyright © 2004 John Wiley & Sons, Ltd.
A stabilized finite element predictor–corrector scheme for the incompressible Navier–Stokes equations using a nodal‐based implementation
Authors: Codina R. , Folch A. 
Published: January 2004

AbstractA finite element model to solve the incompressible Navier–Stokes equations based on the stabilization with orthogonal subscales, a predictor–corrector scheme to segregate the pressure and a nodal based implementation is presented in this paper. The stabilization consists of adding a least‐squares form of the component orthogonal to the finite element space of the convective and pressure gradient terms, which allows to deal with convection‐dominated flows and to use equal velocity–pressure interpolation. The pressure segregation is inspired in fractional step schemes, although the converged solution corresponds to that of a monolithic time integration. Finally, the nodal‐based implementation is based on an a priori calculation of the integrals appearing in the formulation and then the construction of the matrix and right‐hand side vector of the final algebraic system to be solved. After appropriate approximations, this matrix and this vector can be constructed directly for each nodal point, without the need to loop over the elements and thus making the calculations much faster. Some issues related to this implementation for fractional step and our predictor–corrector scheme, which is the main contribution of this paper, are discussed. Copyright © 2004 John Wiley & Sons, Ltd.
Level‐set based numerical simulation of a migrating and dissolving liquid drop in a cylindrical cavity
Authors: Bassano Edmondo 
Published: January 2004

AbstractIn the present paper the dissolution of a binary liquid drop having a miscibility gap and migrating due to thermo‐solutal capillary convection in a cylindrical cavity is studied numerically. The interest in studying this problem is twofold. From a side, in the absence of gravity, capillary migration is one of the main physical mechanisms to set into motion dispersed liquid phases and from the other side, phase equilibria of multi‐component liquid systems, ubiquitous in applications, often exhibit a miscibility gap. The drop capillary migration is due to an imposed temperature gradient between the cavity top and bottom walls. The drop dissolution is due to the fact that initial composition and volume values, and thermal boundary conditions are only compatible with a final single phase equilibrium state. In order to study the drop migration along the cavity and the coupling with dissolution, a previously developed planar two‐dimensional code is extended to treat axis‐symmetric geometries. The code is based on a finite volume formulation. A level‐set technique is used for describing the dynamics of the interface separating the different phases and for mollifying the interface discontinuities between them. The level‐set related tools of redistancing and off‐interface extension are used to enhance code resolution in the critical interface region. Migration speeds and volume variations are determined for different drop radii. Copyright © 2004 John Wiley & Sons, Ltd.
Higher‐order upwind leapfrog methods for multi‐dimensional acoustic equations
Authors: Kim Cheolwan 
Published: January 2004

AbstractA non‐dissipative and very accurate one‐dimensional upwind leapfrog method was successfully extended to higher‐order and multi‐dimensional acoustic equations. The governing equations in characteristic form and staggered grid were utilized to preserve the accuracy. Fourier analysis was performed to find the accurate scheme for acoustics and the resultant two‐dimensional methods were successfully applied to several classical test cases. Copyright © 2004 John Wiley & Sons, Ltd.
Space–time integrated least squares: a time‐marching approach
Authors: Besson Olivier , de Montmollin Gautier 
Published: January 2004

AbstractA time‐marching formulation is derived from the space–time integrated least squares (STILS) method for solving a pure hyperbolic convection equation and is numerically compared to various known methods. Copyright © 2004 John Wiley & Sons, Ltd.
An improved numerical simulator for multiphase flow in porous media
Authors: Garrido I. , Fladmark G. E. , Espedal M. 
Published: January 2004

AbstractIn basin modelling the thermodynamics of a multicomponent multiphase fluid flux are computationally too expensive when derived from an equation of state and the Gibbs equality constraints. In this article we present a novel implicit molar mass formulation technique using binary mixture thermodynamics. The two proposed solution methods, with and without cross derivative terms between components, are based on a preconditionedNewton‐GMRESscheme for each time‐step with analytical computation of the derivatives. These new algorithms reduce significantly the numerical effort for the computation of the molar masses, and we illustrate the behavior of these methods with numerical computations. Copyright © 2004 John Wiley & Sons Ltd.
A ‘poor man's Navier–Stokes equation’: derivation and numerical experiments—the 2‐D case
Authors: McDonough J. M. , Huang M. T. 
Published: January 2004

AbstractWe present a systematic derivation of a discrete dynamical system directly from the two‐dimensional incompressible Navier–Stokes equations via a Galerkin procedure and provide a detailed numerical investigation (covering more than 107 cases) of the characteristic behaviours exhibited by the discrete mapping for specified combinations of the four bifurcation parameters. We show that this simple 2‐D algebraic map, which consists of a bilinearly coupled pair of logistic maps, can produce essentially any (temporal) behaviour observed either experimentally or computationally in incompressible Navier–Stokes flows as the bifurcation parameters are varied in pairs over their ranges of stable behaviours. We conclude from this that such discrete dynamical systems deserve consideration as sources of temporal fluctuations in synthetic‐velocity forms of subgrid‐scale models for large‐eddy simulation. Copyright © 2004 John Wiley & Sons, Ltd.
Microarray proﬁle analysis of toxic cocaine‐induced alterations in the expression of mouse brain gene sequences: a possible ‘protective’ effect of buprenorphine
Authors: Hayase Tamaki , Yamamoto Yoshiko , Yamamoto Keiichi , Muso Eri , Shiota Kohei 
Published: January 2004

AbstractUsing a mouse brain cDNA microarray consisting of 2688 gene sequences, which include unknown sequences with the empirical possibility of expression in the brain, the effects of repeated toxic doses of intraperitoneal (i.p.) cocaine (40 mg kg−1, 4 days) on the expression proﬁle of the cerebral genes were investigated. The modiﬁcations in this proﬁle caused by buprenorphine (BUP) (0.25 mg kg−1 i.p., 4 days), a protective drug against cocaine, were also examined. In the cocaine group, the expression levels reached the recommended increased levels (≥2 times the control value in the saline‐treated control group) in 24.0% of the genes but were equal to or less than the recommended attenuation levels (≤0.5 times the control value) in 14.0% of the genes. In the cocaine–BUP group, the expression levels of the other 15.4% of the total genes were increased and those of the other 18.2% of the total genes were attenuated. However, corresponding to the BUP‐attenuated mortality rate and severity of seizures, the expression levels of 80.1% of the cocaine‐modiﬁed genes with above‐background levels recovered to the recommended normal levels (>0.5 and <2 times the control value). Although statistically signiﬁcant modiﬁcations in the expression of cocaine‐ or BUP‐related brain‐region‐speciﬁc genes were not proved using whole cerebrums, including many unknown genes, our results suggest that the expression of genes related to neuronal cell damage, including non‐peculiar genes related to the damage accompanying convulsive seizures and malignant tumors, were normalized and the genes related to the protection of neural cells were induced by BUP. Copyright © 2004 John Wiley & Sons, Ltd.
Role of caffeic acid phenethyl ester, an active component of propolis, against cisplatin‐induced nephrotoxicity in rats
Authors: Özen Süleyman , Akyol Ömer , Iraz Mustafa , Söğüt Sadık , Özuğurlu Fikret , Özyurt Hüseyin , Odacı Ersan , Yıldırım Zeki 
Published: January 2004

AbstractWe have investigated the effect of caffeic acid phenethyl ester (CAPE) on cisplatin‐induced nephrotoxicity in rats. Administration of a single dose of cisplatin resulted in the elevation of blood urea nitrogen and creatinine in serum, as well as nitric oxide in kidney tissue of rats. Cisplatin also caused reduction of catalase (P < 0.0001), superoxide dismutase (P = 0.149) and glutathrone peroxidase (P < 0.0001) activities in kidney tissue. Although cisplatin caused elevation in malondialdehyde levels and myeloperoxidase activities in kidney tissue, they were not statistically signiﬁcant. Caffeic acid phenethyl ester was found to be protective against cisplatin‐induced antioxidant enzyme reductions. Treatment with free‐radical scavenger CAPE attenuated the increase in plasma blood urea nitrogen and kidney nitric oxide levels, and showed histopathological protection against cisplatin‐induced acute renal failure. Extensive epithelial cell vacuolization, swelling, desquamation and necrosis were observed in the kidney of the cisplatin‐treated rat. There were also larger tubular lumens in cisplatin‐treated rats than those of the control and the CAPE groups. Caffeic acid phenethyl ester caused a marked reduction in the extent of tubular damage. It is concluded that administration of cisplatin imposes an oxidative stress to renal tissue and CAPE confers protection against the oxidative damage associated with cisplatin. This mechanism may be attributed to its free‐oxygen‐radical scavenging activity. Copyright © 2004 John Wiley & Sons, Ltd.
Examination of changes in connective tissue macromolecular components of large white pig skin following application of lewisite vapour
Authors: Lindsay Christopher D. , Hambrook Joy L. , Brown Roger F. R. , Platt Jan C. , Knight Robert , Rice Paul 
Published: January 2004

AbstractThe aim of this study was to provide information about the degradative processes that occur in major connective tissue components in skin following exposure of large white pigs to Lewisite vapour. Of particular interest were alterations in glycoproteins, which are known to mediate dermo‐epidermal attachment (laminin and type IV collagen) and the main collagen found in the dermis (type III collagen). The immunostaining of transfer blots from skin extracts run on sodium dodecyl sulphate polyacrylamide gel electrophoresis gels revealed no evidence of cross‐linking of laminin or of type III or IV collagen. However, there was evidence of a very considerable degradation of laminin and, to a lesser extent, of type IV collagen. Type III collagen did not appear to be degraded in skin exposed to Lewisite. These degradative processes appeared to be more severe than found in previous studies in Yucatan mini‐pigs percutaneously exposed to sulphur mustard, in which only laminin was found to undergo partial cleavage rather than wholesale degradation.The results suggest that damage to macromolecular components in the sub‐epidermal basement membrane in skin which mediate dermo‐epidermal separation processes may be a common feature in the mechanism of action of vesicating agents such as Lewisite and sulphur mustard. It is of interest that the damage to laminin in this study appeared to be more severe than that previously found for sulphur mustard. This suggests that skin can suffer substantial damage yet, in the case of Lewisite exposure, recover relatively quickly. However, Lewisite is not an alkylating agent. Sulphur mustard, in contrast, generates characteristically slow healing lesions, most probably because of its ability to alkylate cell types that normally would be involved in skin regenerative processes. © Crown copyright 2004. Reproduced with the permission of Her Majesty's Stationery Office. Published by John Wiley & Sons, Ltd.
Low‐level exposure of guinea pigs and marmosets to sarin vapour in air: lowest‐observable‐adverse‐effect level (LOAEL) for miosis
Authors: Helden Herman P. M. van , Trap Henk C. , Kuijpers Willem C. , Oostdijk John P. , Benschop Hendrik P. , Langenberg Jan P. 
Published: January 2004

AbstractThe purpose of this pilot study was to indicate, for low‐level exposure of conscious guinea pigs and marmoset monkeys to sarin vapour in air, the lowest‐observable‐adverse‐effect level (LOAEL) of sarin for miosis. This is the concentration × time (C·t) value (t = 5 h) of exposure at which miosis becomes signiﬁcant.The ratio of pupil and iris diameters, measured on digital photographs taken on‐line during exposure, was calculated as a measure for miosis. The exposure concentrations were in the range 7–150 µg m−3 and the exposure times needed to achieve signiﬁcant miosis were in the range 10–300 min. Both vehicle‐ and pyridostigmine‐pretreated animals were used in the experiments. The latter pretreatment resulted in ca. 30% inhibition of erythrocyte acetylcholinesterase in both species.In vehicle‐pretreated guinea pigs and marmosets the pupil size was decreased signiﬁcantly (P < 0.05) at sarin doses of 1.8 ± 0.3 and 2.5 ± 0.8 mg min m−3, respectively. In pyridostigmine‐pretreated guinea pigs and marmosets the pupil size was affected signiﬁcantly (P < 0.05) at 1.8 ± 0.5 and 3.0 ± 0.8 mg min m−3, respectively. Evidently there is no signiﬁcant inﬂuence of pyridostigmine pretreatment on the LOAEL. These data were addressed in light of the recommended occupational and detection limits for sarin vapour in air. It was concluded that miosis will occur during low‐level sarin exposure at levels that are not detectable by the currently ﬁelded alarm systems, assuming that humans are as sensitive for sarin vapour in air as guinea pigs and marmosets. Copyright © 2004 John Wiley & Sons, Ltd.
Assessment of the skin sensitization potency of eugenol and its dimers using a non‐radioisotopic modiﬁcation of the local lymph node assay
Authors: Takeyoshi Masahiro , Noda Shuji , Yamazaki Shunsuke , Kakishima Hiroshi , Yamasaki Kanji , Kimber Ian 
Published: January 2004

AbstractAllergic contact dermatitis is a serious health problem. There is a need to identify and characterize skin sensitization hazards, particularly with respect to relative potency, so that accurate risk assessments can be developed. For these purposes the murine local lymph node assay (LLNA) was developed. Here, we have investigated further a modiﬁcation of this assay, non‐radioisotopic LLNA, which in place of tritiated thymidine to measure lymph node cell proliferation employs incorporation of 5‐bromo‐2'‐deoxyuridine. Using this method we have examined the skin sensitizing activity of eugenol, a known human contact allergen, and its dimers 2,2'‐dihydroxyl‐3,3'‐dimethoxy‐5,5'‐diallyl‐biphenyl (DHEA) and 4,5'‐diallyl‐2'‐hydroxy‐2,3'‐dimethoxy phenyl ether (DHEB). Activity in the guinea pig maximization test (GPMT) also measured. On the basis of GPMT assays, eugenol was classiﬁed as a mild skin sensitizer, DHEA as a weak skin sensitizer and DHEB as an extreme skin sensitizer. In the non‐radioisotopic LLNA all chemicals were found to give positive responses insofar as each was able to provoke a stimulation index (SI) of ≥3 at one or more test concentrations. The relative skin sensitizing potency of these chemicals was evaluated in the non‐radioisotopic LLNA by derivation of an ec3 value (the concentration of chemical required to provoke an SI of 3). The ec3 values calculated were 25.1% for eugenol, >30% for DHEA and 2.3% for DHEB. Collectively these data suggest that assessments of relative potency deriving from non‐radioisotopic LLNA responses correlate well with evaluations based on GPMT results. These investigations provide support for the proposal that the non‐radioisotopic LLNA may serve as an effective alternative to the GPMT where there is a need to avoid the use of radioisotopes. Copyright © 2004 John Wiley & Sons, Ltd.