bluuebunny/crossref_metadata_2025 huggingface dataset:
Sinks, Emissions Intensity Caps and Barriers to Emissions Trading
Authors: Allan Travis , Baylis Kathy
Published: October 2005

The European Union (EU) has raised concerns about the use of sinks and an Emissions Intensity system in Canada and has decided not to allow sinks to be included in its trading system. Despite this restriction, the EU has shown interest in expanding its trading system to include other countries such as Japan and Canada, while Canada hopes to use sinks and a domestic trading system with an Emissions Intensity regulatory mechanism to meet its Kyoto GHG commitments. In this paper, we briefly discuss some of the implications of the Emissions Intensity regulations scheme, and then develop a simple credit model with trade to illustrate the effect of a trade ban put in place by the EU, first, when it is fully binding and second, when there are countries that can act to arbitrage both markets (e.g., Japan). We also look at the possibilities of using harmonization frameworks to control trade, as well as using a form of discounting with respect to Canadian credits. We show that it is highly unlikely that a trade barrier will increase the use of emission reduction (and decreased use of sinks), and that, particularly in the likely case that Canada will import credits, trade barriers will actually increase the use of sinks. We do find, however, that the use of discounting could serve as a possible policy alternative to increase the use of EU reductions, while decreasing the quantity of Canadian sink credits.
Boreal Forest Carbon Sequestration Strategies: A Case Study of the Little Red River Cree First Nation Land Tenures*
Authors: Krcmar Emina , Van Kooten G. Cornelis
Published: October 2005

In this paper, creation of carbon offset and emission reduction credits are examined from the perspective of the Little Red River Cree Nation (LRRCN), a forest tenure holder in northern Alberta. Carbon credits are produced under three scenarios: (1) carbon uptake in forest ecosystems, with postharvest waste left on site; (2) carbon uptake in forests and products; and (3) carbon uptake in forests with harvested fiber used for energy production. A mathematical programming model is used to solve for the minimum prices that cause the LRRCN to include production of carbon credits in its forest management and post‐harvest processing strategies. If LRRCN is paid according to its costs of creating carbon credits, it will opt to use fiber for forest products as this provides the greatest earning potential. If LRRCN faces a fixed price for carbon credits, it will produce fiber for generating electricity in lieu of coal as this strategy has the lowest average cost. However, when costs of feedstock transportation and construction of a power plant are taken into account, carbon uptake in biomass and forest products turn out to be more competitive.
The Dynamic Competitiveness of U.S. Agricultural and Forest Carbon Sequestration
Authors: Lee Heng‐Chi , McCarl Bruce A. , Gillig Dhazn
Published: October 2005

Society is increasingly turning attention toward greenhouse gas emission control with for example the Kyoto Protocol has entered into force. Since many of the emissions come from energy use, high cost strategies might be required until new technological developments reduce fossil fuel dependency or increase energy utilization efficiency. On the other hand biologically based strategies may be used to offset energy related emissions. Agricultural soil and forestry are among the largest carbon reservoirs on the planet; therefore, agricultural and forest activities may help to reduce the costs of greenhouse gas emission mitigation. However, sequestration exhibits permanence related characteristics that may influence this role. We examine the dynamic role of carbon sequestration in the agricultural and forest sectors can play in mitigation. A 100‐year mathematical programming model, depicting U.S. agricultural and forest sectoral activities including land transfers and greenhouse gas consequences is applied to simulate potential mitigation response. The results show that at low cost and in the near term agricultural soil and forest management are dominant sectoral responses. At higher prices and in the longer term biofuels and afforestation take over. Our results reveal that the agricultural and forest sector carbon sequestration may serve as an important bridge to the future helping to hold costs down until energy emissions related technology develops.
Changes in Quebec Cropping Practices in Response to a Carbon Offset Market: A Simulation*
Authors: Morand Hugues , Thomassin Paul J.
Published: October 2005

This paper investigates the response of the Quebec cropping sector to the introduction of carbon credit revenue made available through the implementation of a domestic emission trading and offset system in Canada. Eligible carbon sequestering practices investigated include adoption of moderate tillage and no‐till as well as conversion to a permanent cover crop. Monetary demand for greenhouse gas emissions offsets from the cropping sector is endogenized in the objective function of the Canadian Regional Agriculture Model (CRAM). Changes in cropping sector practices induced by the introduction of carbon prices ranging from $5 to $50 per tonne CO2e are compared to a baseline. Results indicate that almost all of the potential to sequester carbon in agricultural soils in Quebec would lie in the conversion to permanent cover.

Le présent article a examiné la réaction du secteur des cultures du Québec à l'introduction de revenus qui proviendraient de la vente de crédits carbone à la suite de la mise en place de systèmes d'échange de droits d'émissions et de compensations pour les gaz à effet de serre (GES) au Canada. Les pratiques de séquestration du carbone admissibles analysées comprenaient le travail réduit du sol, le semis direct et l'établissement d'une couverture végétale permanente. La demande monétaire pour l'obtention de crédits compensatoires de la part du secteur des cultures a été endogénéisée dans la fonction‐objective du modèle d'analyse régionale de l'agriculture du Canada (CRAM). Les modifications de pratiques du secteur des cultures suscitées par l'introduction de prix du carbone, variant entre 5 $ et 50 $ la tonne d'équivalent‐CO2, ont été comparées à une base de référence. Les résultats ont montré que la quasi‐totalité du potentiel des sols agricoles du Québec à séquestrer le carbone réside dans l'établissement de couvertures végétales permanentes.
Climate Change and the Economics of Farm Management in the Face of Land Degradation: Dryland Salinity in Western Australia
Authors: John Michele , Pannell David , Kingwell Ross
Published: October 2005

Projected changes in climate would affect not only the profitability of agriculture, but also the way it is managed, including the way issues of land conservation are managed. This study provides a detailed analysis of these effects for an extensive dryland farming system in south‐west Australia. Using a whole‐farm linear programming model, with discrete stochastic programming to represent climate risk, we explore the consequences of several climate scenarios. Climate change may reduce farm profitability in the study region by 50% or more compared to historical climate. Results suggest a decline in the area of crop on farms, due to greater probability of poor seasons and lower probability of very good seasons. The reduced profitability of farms would likely affect the capacity of farmers to adopt some practices that have been recommended to farmers to prevent land degradation through dryland salinization. In particular, establishment of perennial pastures (lucerne or alfalfa, Medicago sativa), woody perennials (“oil mallees”, Eucalyptus spp.), and salt‐tolerant shrubs for grazing (“saltland pastures”, Atriplex spp.) may become slightly more attractive in the long run (i.e., relative to other enterprises) but harder to adopt due to their high establishment costs in the context of lower disposable income.
The AEM and Regional Carbonate Aquifer Modeling
Authors: Johnson Cady , Mifflin Martin
Published: October 2005

The analytic element method (AEM) has been applied to a 15,000‐km2 area of the Paleozoic carbonate rock terrain of Nevada. The focus is the Muddy River springs area, which receives 1.44 m3/s (51 ft3/s) of regionally derived ground water, and forms the Muddy River. The study was undertaken early in 2000 to support the development of a cooling water supply for a gas‐fired generation facility 20 km south of the Muddy River springs. The primary objectives of the AEM modeling were to establish a better understanding of regional fluxes and boundary conditions and to provide a framework for examination of more local transient effects using MODFLOW. Geochemical evidence available in 2000 suggested two separate flow fields, one in the north discharging at the springs, and a southern area of small hydraulic gradients. To be conservative, however, hydraulic continuity between the two areas was maintained in the 2000 AEM model. Using new monitoring well data collected in the south, and analyses confirming that seasonal pumping effects in the north are not propagated to the south, a later AEM model that included a barrier calibrated with relative ease. The analytic element model was well suited for simulating an area larger than the immediate area of interest, was easy to modify as more information became available, and facilitated the stepwise development of multiple conceptual models of the site.
The Development of New Analytic Elements for Transient Flow and Multiaquifer Flow
Authors: Strack O.D.L.
Published: October 2005

We deal in this paper with an ongoing development of the analytic element method. We present in outline new analytic line elements that are suitable to model general flow fields, i.e., flow fields that possess a continuously varying areal inflow or outflow. These elements are constructed specifically to model the leakage through leaky layers that separate aquifers in leaky systems and to model transient effects. The leakage or release from storage underneath linear features is modeled precisely by the new elements; the singularity in leakage is matched exactly by the approximate solution. Applications are given for a problem involving leakage and for a case of transient flow. We note that the analytic elements can be used also to reproduce the effect of continuously varying aquifer properties, e.g., the hydraulic conductivity or the elevation of the base of the aquifer. In the latter case, the elements would reproduce the rotation of the flow field caused by the variation in properties, rather than the divergence as for the case of leakage.
Cross‐Borehole Flowmeter Tests for Transient Heads in Heterogeneous Aquifers
Authors: Le Borgne Tanguy , Paillet Frederick , Bour Olivier , Caudal Jean‐Pierre
Published: October 2005

Cross‐borehole flowmeter tests have been proposed as an efficient method to investigate preferential flowpaths in heterogeneous aquifers, which is a major task in the characterization of fractured aquifers. Cross‐borehole flowmeter tests are based on the idea that changing the pumping conditions in a given aquifer will modify the hydraulic head distribution in large‐scale flowpaths, producing measurable changes in the vertical flow profiles in observation boreholes. However, inversion of flow measurements to derive flowpath geometry and connectivity and to characterize their hydraulic properties is still a subject of research. In this study, we propose a framework for cross‐borehole flowmeter test interpretation that is based on a two‐scale conceptual model: discrete fractures at the borehole scale and zones of interconnected fractures at the aquifer scale. We propose that the two problems may be solved independently. The first inverse problem consists of estimating the hydraulic head variations that drive the transient borehole flow observed in the cross‐borehole flowmeter experiments. The second inverse problem is related to estimating the geometry and hydraulic properties of large‐scale flowpaths in the region between pumping and observation wells that are compatible with the head variations deduced from the first problem. To solve the borehole‐scale problem, we treat the transient flow data as a series of quasi–steady flow conditions and solve for the hydraulic head changes in individual fractures required to produce these data. The consistency of the method is verified using field experiments performed in a fractured‐rock aquifer.
Interpretation of Transmissivity Estimates from Single‐Well Pumping Aquifer Tests
Authors: Halford Keith J. , Weight Willis D. , Schreiber Robert P.
Published: October 2005

Interpretation of single‐well tests with the Cooper‐Jacob method remains more reasonable than most alternatives. Drawdowns from 628 simulated single‐well tests where transmissivity was specified were interpreted with the Cooper‐Jacob straight‐line method to estimate transmissivity. Error and bias as a function of vertical anisotropy, partial penetration, specific yield, and interpretive technique were investigated for transmissivities that ranged from 10 to 10,000 m2/d. Cooper‐Jacob transmissivity estimates in confined aquifers were affected minimally by partial penetration, vertical anisotropy, or analyst. Cooper‐Jacob transmissivity estimates of simulated unconfined aquifers averaged twice the known values. Transmissivity estimates of unconfined aquifers were not improved by interpreting results with an unconfined aquifer solution. Judicious interpretation of late‐time data consistently improved estimates where transmissivity exceeded 250 m2/d in unconfined aquifers.
Analysis of Depth‐Dependent Pressure Head of Slug Tests in Highly Permeable Aquifers
Authors: Chen Chia‐Shyun , Wu Ching‐Rung
Published: October 2005

A curve‐matching method is developed for the analysis of depth‐dependent pressure head responding to a slug test in a highly permeable aquifer. The depth dependency is due to the fact that the pressure transducer is placed at depth relatively far from the initial water level. The Springer and Gelhar solution and a depth correction relation are used to generate theoretical curves of pressure head vs. time. A trial‐and‐error procedure is established to find the theoretical curve best fitting the field data by adjusting the two unknown parameters, the horizontal hydraulic conductivity, and the effective length of the water column. Analytic relations for some oscillation characteristics of the converted pressure head are derived. A field example indicates that the theoretical relations and the curve‐matching method developed herein are suitable to deal with the oscillatory head data dependent on depth of measurement. Nevertheless, it is recognized that placing the pressure transducer close to the initial water level and using a small initial water displacement can effectively avoid complicating the data analysis, such that previous, simpler data analysis methods can be used.
Primary Care Management of Patients Following Bariatric Surgery
Authors: Doolen Jessica L. , Miller Sally K.
Published: October 2005

Purpose

To evaluate the nutritional, psychosocial, and other primary care issues faced by nurse practitioners (NPs) and their patients in the long‐term management of the increasing population of patients who have had bariatric surgery.

Data sources

An extensive review of the literature provides the foundation for development of assessment and management strategies highlighted in a case study.

Conclusions

Management of the patient after bariatric surgery does not end with successful surgical healing. Numerous long‐term implications, including significant psychosocial and nutritional issues, require the informed attention of the primary care provider for the rest of the life span.

Implications for practice

Each year an increasing number of obese patients pursue a surgical solution to obesity, up to an estimated 100,000 in 2004. Numerous long‐term health implications are specific to this population. NPs can improve the quality of primary care to these patients by being informed regarding the different procedures and their impact on physiologic phenomena, and the psychosocial issues inherent to extreme weight loss.
A Study of Midlife Women's Reasons for Changing Healthcare Providers
Authors: Kennedy Holly Powell , Taylor Diana , Lee Kathryn A.
Published: October 2005

Purpose

The purpose of this study was to examine the reasons midlife women report for changing healthcare providers and to determine if there were any differences in reasons given for the change based on gender or ethnicity.

Data sources

This was an analysis of data collected from a healthy community‐based sample of midlife women as part of a longitudinal 5‐year study of changes in health outcomes during transition to menopause. Women were queried about their experience in changing healthcare providers.

Conclusions

Over 42% indicated that they had changed health providers because of dissatisfaction with care. The component accounting for the majority of the variance was related to communication issues. There were no significant differences across ethnic groups in decision to change providers or in reasons for their dissatisfaction with care. However, their reports of experiencing racism in the healthcare system were troubling.

Implications for practice

The ability of the provider to communicate with women may have implications in women's choices in health care later in life.
Multiphase
Transport Phenomena in the Diffusion Zone of a PEM Fuel
Cell
Authors: Senn S.
M. , Poulikakos D.
Published: October 2005

In this paper, a thorough model for the porous diffusion layer of a polymer electrolyte fuel cell (PEFC) is presented that accounts for multicomponent species diffusion, transport and formation of liquid water, heat transfer, and electronic current transfer. The governing equations are written in nondimensional form to generalize the results. The set of partial differential equations is solved based on the finite volume method. The effect of downscaling of channel width, current collector rib width, and diffusion layer thickness on the performance of polymer electrolyte membrane (PEM) fuel cells is systematically investigated, and optimum geometric length ratios (i.e., optimum diffusion layer thicknesses, optimum channel, and rib widths) are identified at decreasing length scales. A performance number is introduced to quantify losses attributed to mass transfer, the presence of liquid water, charge transfer, and heat transfer. Based on this model it is found that microchannels (e.g., as part of a tree network channel system in a double-staircase PEM fuel cell) together with diffusion layers that are thinner than conventional layers can provide substantially improved current densities compared to conventional channels with diameters on the order of 1 mm, since the transport processes occur at reduced length scales. Possible performance improvements of 29, 53, and 96 % are reported.
Dynamics of Bubble Motion and Bubble Top Jet Flows From Moving Vapor Bubbles on Microwires
Authors: Christopher David M. , Wang Hao , Peng Xiaofeng
Published: October 2005

Rapid bubble sweeping along heated wires was observed during subcooled nucleate boiling experiments on very fine wires with jet flows emanating from the tops of the vapor bubbles for a variety of conditions. This paper presents experimental results with a numerical analysis of the physical mechanisms causing the experimentally observed bubble motion and jet flows. The results show that the moving bubble creates a nonuniform temperature distribution in the wire by cooling the wire as it moves along the wire with significant heat transfer in the wake behind the bubble. The results verify that the bubble motion is driven by the temperature difference from the front to the back of the bubble, which causes Marangoni flow. The Marangoni flow then thrusts the bubble forward along the wire with the calculated bubble velocities agreeing well with experimental measurements. In addition, the temperature difference from the bottom to the top of the bubble creates a vertical component to the Marangoni flow that results in the jet flows from the bubble tops. Comparisons with experimental observations suggest that the condensation heat transfer at the bubble interface is restricted by noncondensable gases that increase the surface temperature gradient and the resulting Marangoni flow. The numerical results also show that the heat transfer from the wire due to the Marangoni flow is significantly larger than the heat transfer due to the evaporation under the bubble.
Analytical and Experimental Investigation of Laser-Microsphere Interaction for Nanoscale Surface Modification
Authors: Heltzel Alex J. , Theppakuttai Senthil , Howell John R. , Chen Shaochen
Published: October 2005

An analytical and experimental investigation on the features created on silicon by the irradiation of microspheres on the substrate surface with a pulsed laser is presented. Silica microspheres of 1.76μm diameter are deposited on the silicon substrate and are irradiated with a pulsed Nd:YAG laser of wavelength 532nm. An analytical model based on Mie theory is developed, which includes all evanescent terms and does not rely on either far-field or size-parameter approximations. The predicted intensity distributions on the substrate indicate a strong near-field enhancement confined to a very small area (nanometer scale). A multidimensional, numerical model was built to simulate the heat transfer through the silicon. An explicit scheme of the enthalpy method was employed to track the solid∕liquid phase boundary. The experiment was performed for various laser energies used in the modeling, and the features obtained are characterized using a scanning electron microscope. The experimental results correlate well with the predicted results.
Condensation of Ethylene Glycol on Integral-Fin Tubes: Effect of Fin Geometry and Vapor Velocity
Authors: Namasivayam Satesh , Briggs Adrian
Published: October 2005

New experimental data are reported for forced-convection condensation of ethylene glycol on a set of nine single, copper, integral-fin tubes. The first set of five tubes had fin height and thickness of 1.6 and 0.25mm, respectively, with fin spacings of 0.25, 0.5, 1.0, 1.5, and 2.0mm. The second set of four tubes had fin spacing and thickness of 1.0 and 0.5mm, respectively, and fin heights of 0.5, 0.9, 1.3, and 1.6mm. The fins were rectangular in cross section. All tubes had a fin root diameter of 12.7mm. A plain tube of outside diameter 12.7mm was also tested. The tests, which were performed at a near constant pressure of ∼15kPa, covered vapor velocities between 10 and 22m∕s and a wide range of heat fluxes. The best performing tube was that with fin spacing, height, and thickness of 0.5, 1.6, and 0.25mm, respectively, which had an enhancement ratio (compared to the plain tube at the same vapor-side temperature difference and vapor velocity) of 2.5 at the lowest vapor velocity tested, increasing to 2.7 at the highest. For all but two of the tubes, the effect of vapor velocity on the heat-transfer coefficient of the finned tubes was less than on the plain tube, leading to a decrease in enhancement ratio with increasing vapor velocity. For two of the tubes, however, the enhancement ratio increased with increasing vapor velocity, which is the opposite trend to that found in most earlier experimental studies. This effect was thought to be due to the slight reduction in condensate flooding between the fins of these two tubes because of vapor shear.
Condensation on a Horizontal Wire-Wrapped Tube
Authors: Murase Takahiro , Briggs Adrian , Wang Hua Sheng , Rose John W.
Published: October 2005

Measurements for film condensation of steam, R113 and ethylene glycol on a horizontal wire-wrapped tube are reported. All measurements were made at near atmospheric vapor pressure and with coolant at around 20°C. Care was taken to avoid error due to the presence of air in the vapor. Complete wetting (film condensation) was observed in all cases. Wire diameter and pitch of winding were systematically varied and heat-transfer measurements made for a range of coolant flow rates. Data, in the form of heat flux and vapor-to-surface temperature difference, are presented. These were used to determine enhancement ratios (ratio of heat flux or heat-transfer coefficient for a wire-wrapped tube to the corresponding value for a plain tube at the same vapor-to-surface temperature difference). Enhancement ratios exceeding 3 for R113 and 2 for steam and ethylene glycol were obtained. The results are discussed in the light of earlier measurements and theory.
Diffusion-Based Thermal Tomography
Authors: Bakirov Vadim F. , Kline Ronald A.
Published: October 2005

Thermal imaging is one of the fastest growing areas of nondestructive testing. The basic idea is to apply heat to a material and study the way the temperature changes within the material to learn about its composition. The technique is rapid, relatively inexpensive, and, most importantly, has a wide coverage area with a single experimental measurement. One of the main research goals in thermal imaging has been to improve flaw definition through advanced image processing. Tomographic imaging is a very attractive way to achieve this goal. Although there have been some attempts to implement tomographic principles for thermal imaging, they have been only marginally successful. One possible reason for this is that conventional tomography algorithms rely on wave propagation (either electromagnetic or acoustic) and are inherently unsuitable for thermal diffusion without suitable modifications. In this research program, a modified approach to thermal imaging is proposed that fully accounts for diffusion phenomena in a tomographic imaging algorithm. Here, instead of the large area source used in conventional thermal imaging applications, a raster scanned point source is employed in order to provide the well-defined source-receiver positions required for tomographic imaging. An algorithm for the forward propagation problem, based on the Galerkin finite element method in connection with the corresponding weak formulation for the thermal diffusion is considered. A thermal diffusion modified version of the algebraic reconstruction technique (ART) is used for image reconstruction. Examples of tomographic images are presented from synthetically generated data to illustrate the utility of the approach.
An Investigation Into the Effect of Subcooled Liquid Inertia on Flow-Change-Induced Transient Flow Surges in Horizontal Condensing Flow Systems
Authors: Kobus C. J.
Published: October 2005

The objective of this research is to investigate large-scale transient flow surges of the condensate leaving in-tube condensing flow systems because of perturbations in the inlet vapor flow rate, and the influence of the subcooled liquid inertia of the condensate on these transient responses. Small changes in the inlet vapor flow rate momentarily cause large transient flow surges in the outlet liquid flow rate. Condensate inertia is seen to destabilize the system into an underdamped behavior where the flow rate can overshoot the final steady-state position several times. A one-dimensional, two-fluid, distributed parameter system mean void fraction (SMVF) model of the time-dependent distribution of liquid and vapor within the two-phase region is developed for predicting these transient characteristics, which it is seen to do quite well, especially when consideration is given to the complex nature of the problem.
Low Reynolds Number Film Flow Down a Three-Dimensional Bumpy Surface
Authors: Wang C. Y.
Published: October 2005

The slow film flow down a doubly periodic bumpy surface is studied for the first time. Perturbations on the primary variables and the complex boundary conditions lead to a system of successive equations. The secondary flow and the free surface shape depend on the wavelength of the bumps and a surface tension-inclination parameter. There exists an optimum aspect ratio of the protuberances for maximal flow rate.
Prediction of Flutter of Turbine Blades in a Transonic Annular Cascade
Authors: McBean Ivan , Hourigan Kerry , Thompson Mark , Liu Feng
Published: October 2005

A parallel multiblock Navier-Stokes solver with the k‐ω turbulence model is used to solve the unsteady flow through an annular turbine cascade, the transonic Standard Test Case 4, Test 628. Computations are performed on a two- and three-dimensional model of the blade row with either the Euler or the Navier-Stokes flow models. Results are compared to the experimental measurements. Comparisons of the unsteady surface pressure and the aerodynamic damping are made between the three-dimensional, two-dimensional, inviscid, viscous simulations, and experimental data. Differences are found between the stability predictions by the two- and three-dimensional computations, and the Euler and Navier-Stokes computations due to three-dimensionality of the cascade model and the presence of a boundary layer separation, respectively.
Influence of Ribbon Structure Rough Wall on the Microscale Poiseuille Flow
Authors: Wang Haoli , Wang Yuan , Zhang Jiazhong
Published: October 2005

The regular perturbation method is introduced to investigate the influence of two-dimensional roughness on laminar flow in microchannels between two parallel plates. By superimposing a series of harmonic functions with identical dimensional amplitude as well as the same fundamental wave number, the wall roughness functions are obtained and the relative roughness can be determined as the maximal value of the product between the normalized roughness functions and a small parameter. Through modifying the fundamental wave number, the dimensionless roughness spacing is changed. Under this roughness model, the equations with respect to the disturbance stream function are obtained and analyzed numerically. The numerical results show that flowing in microchannels are more complex than that in macrochannels; there exist apparent fluctuations with streamlines and clear vortex structures in microchannels; the flow resistances are about 5–80% higher than the theoretical value under different wall-roughness parameters. Furthermore, analysis shows that the effect of roughness on the flow pattern is distinct from that on the friction factor.
A Priori Assessments of Numerical Uncertainty in Large-Eddy Simulations
Authors: Jordan Stephen A.
Published: October 2005

Current suggestions for estimating the numerical uncertainty in solutions by the Large-Eddy Simulation (LES) methodology require either a posteriori input or reflect global assessments. In most practical applications, this approach is rather costly for the user and especially time consuming due to the CPU effort needed to reach the statistical steady state. Herein, we demonstrate two alternate a priori graphical exercises. An evaluation of the numerical uncertainty uses the turbulent quantities given by the area under the wave number spectra profiles. These profiles are easily constructed along any grid line in the flow domain prior to the collection of the turbulent statistics. One exercise involves a completion of the spectrum profile beyond the cutoff wave number to the inverse of Kolmorgorov’s length scale by a model of isotropic turbulence. The other extends Richardson Extrapolation acting on multiple solutions. Sample test cases of both LES solutions and direct numerical simulations as well as published experimental data show excellent agreement between the integrated matched spectra and the respective turbulent statistics. Thus, the resultant uncertainties themselves provide a useful measure of accumulated statistical error in the resolved turbulent properties.
Free Surface Length Scale Estimation in Hydraulic Jumps
Authors: Mouaze D. , Murzyn F. , Chaplin J. R.
Published: October 2005

In the context of recent work by Brocchini and Peregrine [J. Fluid Mech., 449, pp. 225–254 (2001a); 449, pp. 255–290 (2001b)] in this paper we aim to document free surface elevations and free surface length scales in hydraulic jumps with Froude numbers between 1.98 and 4.82. Although information on bubble size, frequency, and velocities in hydraulic jumps is available in the literature, there is not much data on the features of the free surface, or on mixing layer thickness. In the present case, measurements at the free surface have been realized with two “homemade” miniature resistive wire gauges made of two parallel 50μm diameter wires 1mm apart. These instruments were calibrated dynamically over a range of frequencies up to 20Hz. The present results extend the range of Froude numbers for which two-phase measurements in hydraulic jumps are available. In most respects, it confirms earlier results obtained with different experimental techniques. Length scales at the free surface are deduced from a cross-correlation analysis of wire gauge measurements, and are compared with similar data obtained from images of the surface.
High-Speed Observation of a Cavitating Jet in Air
Authors: Soyama Hitoshi
Published: October 2005

The use of cavitation impact is a practical method for improving the fatigue strength of metals in the same way as shot peening. In the case of peening using cavitation impact, cavitation is produced by a high-speed submerged water jet with cavitation, i.e., a cavitating jet. A cavitating jet in air was successfully generated by injecting a high-speed water jet into a low-speed water jet injected into air using a concentric nozzle. In order to investigate the various appearances of cavitating jets in air, an observation was carried out using high-speed photography and high-speed video recording. In this study, periodical shading of the cavitation cloud was observed and the frequency of the shading was found to be a function of the injection pressure of the low-speed water jet. Unsteadiness of the low-speed water jet, which is related to the periodical shading of the cloud, was also observed.
Aspects of Shear Layer Unsteadiness in a Three-Dimensional Supersonic Wake
Authors: Kastengren Alan L. , Dutton J. Craig
Published: October 2005

The near wake of a blunt-base cylinder at 10° angle-of-attack to a Mach 2.46 free-stream flow is visualized at several locations to study unsteady aspects of its structure. In both side-view and end-view images, the shear layer flapping grows monotonically as the shear layer develops, similar to the trends seen in a corresponding axisymmetric supersonic base flow. The interface convolution, a measure of the tortuousness of the shear layer, peaks for side-view and end-view images during recompression. The high convolution for a septum of fluid seen in the middle of the wake indicates that the septum actively entrains fluid from the recirculation region, which helps to explain the low base pressure for this wake compared to that for a corresponding axisymmetric wake.
Investigation of the Influence of Injection Rate Shaping on the Spray Characteristics in a Diesel Common Rail System Equipped with a Piston Amplifier
Authors: Benajes J. , Payri R. , Molina S. , Soare V.
Published: October 2005

The quality of the mixing process of fuel and air in a direct injection diesel engine relies heavily on the way the spray develops when injected into the combustion chamber. Among other factors, the spray development depends on the injection rate of the fuel delivered by the injector. The paper presents a study, at both a macroscopic and microscopic level, of a Diesel spray generated by a common-rail injection system featuring a piston pressure amplifier. By modifying the timing and the duration of the injector and amplifier piston actuation, it is possible to obtain high injection pressures up to 180MPa, and different shapes for the injection rate, which would not be achievable with a regular common rail injection system. The spray evolution produced by three different injection rate shapes (square, ramp, and boot) has been investigated in an injection test rig, by means of visualization and PDPA techniques, at different injection conditions. The main conclusions are the important effect on spray penetration of the initial injection rate evolution and the small influence of the maximum injection pressure attained at the end of the injection event. Smaller or even negligible effects have been found on the spray cone angle and on the droplet Sauter mean diameter.
A Practical Combined Computation Method of Mean Through-Flow for 3D Inverse Design of Hydraulic Turbomachinery Blades
Authors: Peng Guoyi
Published: October 2005

A practical combined computation method of the circumferentially averaged mean through-flow is presented for 3D inverse computations of hydraulic turbomachinery blades to consider the influence of interrelated hydraulic components. A comprehensive computation domain including the runner blades and related components is adopted and the mean flow is calculated altogether by solving a set of rotational flow governing equations simultaneously. The method has been applied to the case of Kaplan turbine. Computational results were compared to experimental data and their agreement was confirmed. Numerical investigation indicates that the mean flow is dependent on the configuration of guide vanes and the effect of runner blades reaches to the far upstream. The importance of properly taking account of the effect of blade geometry and the influence of interrelated hydraulic components is demonstrated.
Prediction of Cascade Flows With Innovative Second-Moment Closures
Authors: Borello Domenico , Hanjalic Kemal , Rispoli Franco
Published: October 2005

We report on the performances of two second-moment turbulence closures in predicting turbulence and laminar-to-turbulent transition in turbomachinery flows. The first model considered is the one by Hanjalic and Jakirlic (HJ) [Comput. Fluids, 27(2), pp. 137–156 (1998)], which follows the conventional approach with damping functions to account for the wall viscous and nonviscous effect. The second is an innovative topology-free elliptic blending model, EBM [R. Manceau and K. Hanjalic, Phys. Fluids, 14(3), pp. 1–11 (2002)], here presented in a revised formulation. An in-house finite element code based on a parallel technique is used for solving the equation set [Borello et al., Comput. Fluids, 32, pp. 1017–1047 (2003)]. The test cases under scrutiny are the transitional flow on a flat plate with circular leading edge (T3L ERCOFTAC-TSIG), and the flow around a double circular arc (DCA) compressor cascade in quasi-off-design condition (i=−1.5°) [Zierke and Deutsch, NASA Contract Report 185118 (1989)]. The comparison between computations and experiments shows a satisfactory performance of the HJ model in predicting complex turbomachinery flows. The EBM also exhibits a fair level of accuracy, though it is less satisfactory in transition prediction. Nevertheless, in view of the robustness of the numerical formulation, the relative insensitivity to grid refinement, and the absence of topology-dependent parameters, the EBM is identified as an attractive second-moment closure option for computation of complex 3D turbulent flows in realistic turbomachinery configurations.
POTENTIAL APPLICATION OF SUPERCONDUCTING MATERIAL YBa2Cu3O7-x AS OXYGEN RESISTANCE SENSORS
Authors: ZHU ZHILI , GUO LANJING , WANG HAIYAN , TIAN GUOXUN , LU HONGXIA , YANG DELIN , LI XINJIAN , HU XING
Published: October 2005

Potential application of superconducting material YBa 2 Cu 3 O 7-x for both bulk and thick film samples as oxygen resistance sensors was investigated. The oxygen diffusion kinetics of YBa 2 Cu 3 O 7-x was studied by thermal analysis technology and the resistance dependence on the oxygen partial pressure was measured. The experiment shows that the changing of oxygen pressure can result in oxygen desorption and absorption, and in-diffusion is more rapid than out-diffusion. The oxygen stoichiometry and conductivity of YBa 2 Cu 3 O 7-x have strong relations with temperature and the partial pressure of environmental oxygen. The responding properties of the thick film to the changing of oxygen partial pressure have been improved in comparison with the bulk samples. The sensitivity to the oxygen pressure of thick film varies with temperature and reaches a maximum value 62 at 650°C.
EVOLVING SCALE-FREE NETWORK MODEL WITH TUNABLE CLUSTERING
Authors: WANG BING , TANG HUANWEN , ZHANG ZHONGZHI , XIU ZHILONG
Published: October 2005

The Barabási–Albert (BA) model is extended to include the concept of local world and the microscopic event of adding edges. With probability p, we add a new node with m edges which preferentially link to the nodes presented in the network; with probability 1-p, we add m edges among the present nodes. A node is preferentially selected by its degree to add an edge randomly among its neighbors. Using the continuum theory and the rate equation method we get the analytical expressions of the power-law degree distribution with exponent γ=3 and the clustering coefficient c(k)~k-1+c. The analytical expressions are in good agreement with the numerical calculations.
LOW-TEMPERATURE THERMODYNAMIC PROPERTIES OF A ONE-DIMENSIONAL GENERALIZED WIGNER CRYSTAL
Authors: SLAVIN V.
Published: October 2005

The low-temperature thermodynamic properties of a one-dimensional generalized Wigner crystal at arbitrary values of electron density and arbitrary number of interacting electrons are studied. The modified transfer-matrixes method is applied. It is shown that increasing the number of interacting electrons leads to the appearance of more and more fine "stairs" in low-temperature dependence of chemical potential against electron density. An influence of the disorder in host-lattice site positions on thermodynamic characteristics of the system is considered. It is established that the disorder destroys the "stairs".
XRD STUDY OF THE Er1-xDyxNi2B2C SYSTEM MAGNETIC SUPERCONDUCTORS
Authors: QIN XIAOLING , CAO SHIXUN , YU LIMING , ZHANG JINCANG , NISHIMURA KATSUHIKO , MORI KATSUNORI
Published: October 2005

The magnetic superconducting samples of the intermetallic Er 1-x Dy x Ni 2 B 2 C system are prepared by the arc melting method. Powder XRD measurements are systematically conducted and analyzed. The change of microstructure reflects the contribution of the different magnetic moments and the ionic radius difference of Er and Dy to the crystal structure in the substitution of Er 1-x Dy x Ni 2 B 2 C system. The element substitution of Dy for Er in the magnetic superconducting compound is verified commendably in microstructure level by the powder XRD experiment.
ELECTRONIC STRUCTURE CALCULATIONS ON MoTe2 WITH ROTATED PLANES
Authors: TLAHUICE A. , FLORES E. , GALVÁN D. H.
Published: October 2005

Electronic structure calculations have been carried out using Extended Hückel tight-binding method for 2 H — MoTe 2 for the cases both unrotated and with rotated planes. It has been found that relative rotations of the tellurium layers ranging from 5 to 16 degrees have the same total energies and total energies/atom as the unrotated structure. Moreover, an increased in metallic behavior has been observed, as long as the degrees of rotated planes are increased. Finally, good agreement has been found among previous experimental measurements in the diffraction pattern of irradiated MoTe 2 and our calculated 5, 6 and 7 degrees of rotations.
SOLUTION TO THE CLEBSCH–GORDAN PROBLEM FOR REPRESENTATIONS OF QUIVERS OF TYPE $\tilde{\mathbb{A}}_n$
Authors: HERSCHEND MARTIN
Published: October 2005

We solve the Clebsch–Gordan problem for rep𝕂 Q (i.e. we describe the Krull–Schmidt decomposition of A ⊗ B for all A, B ∈ rep𝕂 Q) in case 𝕂 is an algebraically closed field of characteristic 0 and Q is a quiver of type [Formula: see text]. The underlying tensor product is defined point-wise and arrow-wise.
THE RESTRICTIONS OF REPRESENTATIONS OF ALGEBRAIC GROUPS OF TYPES Bn AND Dn TO SUBGROUPS OF TYPE A2
Authors: OSINOVSKAYA ANNA A.
Published: October 2005

Restrictions of modular p-restricted representations of algebraic groups of types Bn (n > 2) and Dn (n > 3) to naturally embedded subgroups of type A2 are studied. The composition factors of such restrictions are determined in the case of locally small highest weights. Here the class of locally small weights depends upon the type of a group considered and is defined in terms of their values on four simple roots linked at the Dynkin diagram of a group.
MODULAR BRANCHING RULES FOR 2-COLUMN DIAGRAM REPRESENTATIONS OF GENERAL LINEAR GROUPS
Authors: BARANOV A. A. , SUPRUNENKO I. D.
Published: October 2005

In this paper branching rules for the polynomial irreducible representations of the general linear groups in positive characteristic with highest weights labeled by partitions of the form (2a, 1b, 0c) and their restrictions to the special linear groups are found. The submodule structure of the restrictions of the corresponding irreducible modules for the group GLn(F) (or SLn(F)) to the naturally embedded subgroup GLn-1(F) (or SLn-1(F)) is determined. As a corollary, inductive systems of irreducible representations for GL∞(F) and SL∞(F) that consist of representations indicated above, are classified. The submodule structure of the relevant Weyl modules is refined.
PRESENTATION OF QUANTUM GENERALIZED SCHUR ALGEBRAS
Authors: LI LIBIN
Published: October 2005

We obtain the explicit generators of the annihilator ideal for the tensor product of any finite dimensional simple module over quantum group [Formula: see text], by using the weight property of ideals in [Formula: see text] when q is not a root of unity. As an application, we give a presentation of quantum generalized Schur algebra.
STRATIFYING SYSTEMS, FILTRATION MULTIPLICITIES AND SYMMETRIC GROUPS
Authors: ERDMANN KARIN
Published: October 2005

We show that the theorem by Hemmer and Nakano, on uniqueness of Specht filtration multiplicities, can be proved working entirely with representations of symmetric groups, or Hecke algebras. Furthermore, we give a new proof that Schur algebras are quasi-hereditary provided the characteristic of the field is at least 5. Our tools are some more general results on stratifying systems.
A FEW HOMOLOGICAL CHARACTERIZATIONS OF COMPACT SEMISIMPLE RINGS
Authors: ALB ALINA , URSUL MIHAIL
Published: October 2005

Fix any compact ring R with identity. We associate to R the following categories of topological R-modules:

(i) R𝔇 (𝔇R) the category of all discrete topological left (right) R-modules;

(ii) Rℭ (ℭR) the category of all compact left (right) R-modules.

We have introduced the following notions (analogous with classical notions of module theory):

(i) the tensor product [Formula: see text] of A ∈ ℭR and B ∈Rℭ ([Formula: see text] has a structure of a compact Abelian group);

(ii) a topologically semisimple module;

(iii) a compact topologically flat module.

We give a characterization of compact semisimple rings by using of flat modules.
Molecular Approaches in Pediatric Oncology
Authors: Khanna Chand , Helman Lee J.
Published: October 2005

The use of molecular approaches has become part of the standard of care in the management of pediatric cancer patients. Molecular approaches are now included in the initial diagnosis, definition of prognostically distinct patient subgroups, selection of patients for specific therapies, prediction of risk for toxicities to therapy, and monitoring of patients receiving both conventional and novel targeted therapies. This clinical application of molecular medicine has been based on a growing molecular understanding of cancer biology. Studies of pediatric cancers have contributed to this understanding in many ways. We present a model for understanding cancer biology, using specific examples taken from pediatric oncology, and then discuss the application of molecular techniques to the clinical management of pediatric cancer patients.