bluuebunny/crossref_metadata_2025 huggingface dataset:
ASRI2005‐93  A new aspect of reproduction in infertility associated with polcystic ovarian syndrome
Authors: Mehrotra V , Saini P
Published: August 2005

Introduction:  Polycystic ovarian syndrome (PCOS) is one of the commonest causes of anovulatory infertility presenting with menstrual abnormalities. The common treatment is to ovulate and conceive is Clomiphene citrate but 50% becomes pregnant with first trimester abortion rate high. The aim is for better judgment of efficacy of Clomiphene citrate and recombinant FSH for ovulation induction.

Method:  Patients (120) were divided in two groups: treated with Clomiphene citrate and other on recombinant FSH. Ovarian response was monitored and HCG given to trigger ovulation after appropriate follicular development. The prime out come major cumulative pregnancies after undergoing up to 4 treatment cycles. Results: The study showed that aspects of reproduction with pregnancy rate were more in recombinant FSH as compare to clomiphene citrate. Abortion rate was less in recombinant FSH then clomiphene citrate group. The incidences of OHSS were least in both. The main aspects of reproduction after 4‐treatment cycle were 45.8% with recombinant FSH and only 11.2% with Clomiphene citrate.

Conclusions:  Various RCTs have been done before showing benefits of Gonadotrophins over Clomiphene citrate. Study suggests that recombinant FSH effective alternative of Clomiphene citrate in first line treatment for the reproduction of anovulatory PCOS patients.
Staffing Alone: Unilateral Action and the Politicization of the Executive Office of the President, 1988‐2004
Authors: LEWIS DAVID E.
Published: August 2005

This president's power to determine the number of appointed positions in bureaucratic agencies is an important and understudied aspect of presidential unilateral power. It can have a significant impact on policy implementation. In this article, I describe the mechanics of how presidents alter the number of political appointees and explain when presidents want to politicize. I focus on how presidents balance their competing desires for agencies to share presidential preferences but also be competent at what they do. I examine presidential staffing choices with new data on appointees in the Executive Office of the President during 1988‐2004. I find some preliminary evidence that presidents add more appointees when their preferences diverge from those of an agency and that presidents are mindful of how politicization will impact agency performance. I conclude that more attention should be paid to how presidents unilaterally influence the number and depth of political appointees in the federal bureaucracy.
The Law: Scholarly Support for Presidential Wars
Authors: FISHER LOUIS
Published: August 2005

For the past half‐century, political scientists and historians have given much intellectual support to the growth of presidential power. They have imbued the presidency with magical qualities of expertise and good intentions, motivated by the “national interest” rather than the local and parochial ambitions that supposedly drive members of Congress. In this decision to concentrate power in the president, scholars gave short shrift to legal boundaries and constitutional principles, including checks and balances and separation of powers. Supported by the academic community, presidents now regularly claim that the Constitution allows them to wage war against other countries without receiving either a declaration or authorization from Congress.
PAY SATISFACTION AND ORGANIZATIONAL OUTCOMES
Authors: CURRALL STEVEN C. , TOWLER ANNETTE J. , JUDGE TIMOTHY A. , KOHN LAURA
Published: August 2005

Using multi level and multi method data, we investigated the relationship between pay satisfaction and outcomes at the organizational level of analysis. Individual‐level survey data on pay satisfaction (including satisfaction with pay level, satisfaction with pay structure, satisfaction with pay raises, and benefits) were collected from 6,394 public school teachers. Organizational‐level outcome data, both survey and archival, were collected from the 117 public school districts employing these teachers. With respect to its influence on organizational outcomes, pay satisfaction was positively related to school district‐level academic performance and negatively related to average teacher intention to quit. We also explored the relationship between district‐level union satisfaction and pay satisfaction, which was found to be positive. We discuss implications of our findings for for‐profit companies that are knowledge based and human capital intensive (e.g., the service sector) and address possible future directions for research on pay satisfaction.
AN EVALUATION OF GENERIC TEAMWORK SKILLS TRAINING WITH ACTION TEAMS: EFFECTS ON COGNITIVE AND SKILL‐BASED OUTCOMES
Authors: ELLIS ALEKSANDER P.J. , BELL BRADFORD S. , PLOYHART ROBERT E. , HOLLENBECK JOHN R. , ILGEN DANIEL R.
Published: August 2005

This study evaluated the utility of generic teamwork skills training for enhancing the effectiveness of action teams. Results from 65 4‐person action teams working on an interdependent command and control simulator revealed that generic teamwork skills training had a significant and positive impact on both cognitive and skill‐based outcomes. Trained team members evidenced higher levels of declarative knowledge regarding teamwork competencies and demonstrated greater proficiency in the areas of planning and task coordination, collaborative problem‐solving, and communication. Furthermore, results indicated that cognitive and skill based outcomes were interrelated. Team members' declarative knowledge regarding teamwork competencies positively affected planning and task coordination, collaborative problem solving, and communication skills. However, we found that the effects of declarative knowledge differed across team members depending on their roles and responsibilities. The team benefited the most from the knowledge held by the team member who occupied the most critical position in the workflow. Implications of these findings for future research and practice are discussed.
A PROCESS FOR CONTENT VALIDATION OF EDUCATION AND EXPERIENCED‐BASED MINIMUM QUALIFICATIONS: AN APPROACH RESULTING IN FEDERAL COURT APPROVAL
Authors: BUSTER MAURY A. , ROTH PHILIP L. , BOBKO PHILIP
Published: August 2005

The use of education and experience minimum qualifications (MQs) is nearly ubiquitous in employment settings, yet it appears to be rare that such MQs are validated by the end user (either via content validity or criterion‐related validation approaches). In this article, we present a method of content‐validating MQs that is related to a procedure noted by Levine, Maye, Ulm, and Gordon (1997), and we demonstrate the method's application for an upper‐level management position in a state agency. Our procedure is based on adherence to the Uniform Guidelines and sound professional practice. In addition, the procedure was heard in a federal court proceeding (deposition and expert testimony in relation to 3 jobs), was approved by that court, and we discuss the court's findings. In particular, the court found, “The MQ development process used by the State Personnel Department (SPD) is consistent with the requirements of the Guidelines and leads to content‐valid MQs.” Given data available to us for another job, we also show that the obtained MQs may result in less adverse impact than a previously determined, task‐based set of MQs.
HOW SOCIAL DOMINANCE ORIENTATION AND JOB STATUS INFLUENCE PERCEPTIONS OF AFRICAN‐AMERICAN AFFIRMATIVE ACTION BENEFICIARIES
Authors: AQUINO KARL , STEWART MARCUS M. , REED AMERICUS
Published: August 2005

This paper examines evaluative judgments about an African‐American beneficiary of affirmative action (AA) in two studies. Based on a motivated social cognition model, we test whether the use of AA, social dominance orientation (SDO), and job status jointly influence judgments about the future job performance and career progression of an AA beneficiary. In a sample of 244 undergraduate business students, Study 1 showed that SDO and AA interact to predict job‐related performance expectations, and AA and job status interact to predict career progression expectations. Study 2 used a different sample of 190 business undergraduates to test whether the effects of AA, job status, SDO and their interactions on evaluative judgments is mediated by stereotype application. Results showed that different dimensions of stereotypes mediated the relationships between SDO, job status and the AA × SDO interaction.
SALMONELLA DETECTION BY POLYMERASE CHAIN REACTION AFTER PRE‐ENRICHMENT OF FEED SAMPLES
Authors: SALOMONSSON ANN‐CHRISTINE , ASPÁN ANNA , JOHANSSON SARA , HEINO ANJA , HÄGGBLOM PER
Published: August 2005

A polymerase chain reaction (PCR) procedure was developed for analysis of viable Salmonella spp. in feed samples and scrapings from feed mills. The objective was to develop a cost‐effective, user‐friendly method that could be performed within ordinary working hours. A single pre‐enrichment was enough for most feed raw materials. However, scrapings and pellets required additional pre‐enrichment. The results indicate that inhibition of the PCR reaction was correlated with a pH value below 7.0 in the first pre‐enrichment. Results of the PCR procedure were in agreement with the established culture‐based Nordic Committee on Food Analysis method in spiked samples. The developed PCR procedure can be used as a routine analysis method for feed samples and samples from a Salmonella feed control program based on hazard analysis critical control point principles.
Disruption of CFTR chloride channel alters mechanical properties and cAMP‐dependent Cl− transport of mouse aortic smooth muscle cells
Authors: Robert Renaud , Norez Caroline , Becq Frédéric
Published: August 2005

Chloride (Cl−) channels expressed in vascular smooth muscle cells (VSMC) are important to control membrane potential equilibrium, intracellular pH, cell volume maintenance, contraction, relaxation and proliferation. The present study was designed to compare the expression, regulation and function of CFTR Cl− channels in aortic VSMC from Cftr+/+ and Cftr−/− mice. Using an iodide efflux assay we demonstrated stimulation of CFTR by VIP, isoproterenol, cAMP agonists and other pharmacological activators in cultured VSMC from Cftr+/+. On the contrary, in cultured VSMC from Cftr−/− mice these agonists have no effect, showing that CFTR is the dominant Cl− channel involved in the response to cAMP mediators. Angiotensin II and the calcium ionophore A23187 stimulated Ca2+‐dependent Cl− channels in VSMCs from both genotypes. CFTR was activated in myocytes maintained in medium containing either high potassium or 5‐hydroxytryptamine (5‐HT) and was inhibited by CFTRinh‐172, glibenclamide and diphenylamine‐2,2′‐dicarboxylic acid (DPC). We also examined the mechanical properties of aortas. Arteries with or without endothelium from Cftr−/− mice became significantly more constricted (∼2‐fold) than that of Cftr+/+ mice in response to vasoactive agents. Moreover, in precontracted arteries of Cftr+/+ mice, VIP and CFTR activators induced vasorelaxation that was altered in Cftr−/− mice. Our findings suggest a novel mechanism for regulation of the vascular tone by cAMP‐dependent CFTR chloride channels in VSMC. To our knowledge this study is the first to report the phenotypic consequences of the loss of a Cl− channel on vascular reactivity.
Influence of recombinant human erythropoietin treatment on pulmonary O2 uptake kinetics during exercise in humans
Authors: Wilkerson Daryl P. , Rittweger Jörn , Berger Nicolas J. A. , Naish Patrick F. , Jones Andrew M.
Published: August 2005

We hypothesized that 4 weeks of recombinant human erythropoietin (RhEPO) treatment would result in a significant increase in haemoglobin concentration ([Hb]) and arterial blood O2‐carrying capacity and that this would (1) increase peak pulmonary oxygen uptake during ramp incremental exercise, and (2) speed kinetics during ‘severe’‐, but not ‘moderate’‐ or ‘heavy’‐intensity, step exercise. Fifteen subjects (mean ±s.d. age 25 ± 4 years) were randomly assigned to either an experimental group which received a weekly subcutaneous injection of RhEPO (150 IU kg−1; n= 8), or a control group (CON) which received a weekly subcutaneous injection of sterile saline (10 ml; n= 7) as a placebo, for four weeks. The subjects and the principal researchers were both blind with respect to the group assignment. Before and after the intervention period, all subjects completed a ramp test for determination of the gas exchange threshold (GET) and , and a number of identical ‘step’ transitions from ‘unloaded’ cycling to work rates requiring 80% GET (moderate), 70% of the difference between the GET and (heavy), and 105% (severe) as determined from the initial ramp test. Pulmonary gas exchange was measured breath‐by‐breath. There were no significant differences between the RhEPO and CON groups for any of the measurements of interest ([Hb], kinetics) before the intervention. Four weeks of RhEPO treatment resulted in a 7% increase both in [Hb] (from 15.8 ± 1.0 to 16.9 ± 0.7 g dl−1; P < 0.01) and (from 47.5 ± 4.2 to 50.8 ± 10.7 ml kg−1·min−1; P < 0.05), with no significant change in CON. RhEPO had no significant effect on kinetics for moderate (Phase II time constant, from 28 ± 8 to 28 ± 7 s), heavy (from 37 ± 12 to 35 ± 11 s), or severe (from 33 ± 15 to 35 ± 15 s) step exercise. Our results indicate that enhancing blood O2‐carrying capacity and thus the potential for muscle O2 delivery with RhEPO treatment enhanced the peak but did not influence kinetics, suggesting that the latter is principally regulated by intracellular (metabolic) factors, even during exercise where the requirement is greater than the , at least in young subjects performing upright cycle exercise.
Effects of nitric oxide synthase inhibition by l‐NAME on oxygen uptake kinetics in isolated canine muscle in situ
Authors: Grassi Bruno , Hogan Michael C. , Kelley Kevin M. , Howlett Richard A. , Gladden L. Bruce
Published: August 2005

Nitric oxide (NO) has an inhibitory action on O2 uptake at the level of the mitochondrial respiratory chain. The aim of this study was to evaluate the effects of NO synthase (NOS) inhibition on muscle kinetics. Isolated canine gastrocnemius muscles in situ (n= 6) were studied during transitions from rest to 4‐min of electrically stimulated contractions corresponding to ∼60% of the muscle peak . Two conditions were compared: (i) Control (CTRL) and (ii) l‐NAME, in which the NOS inhibitor l‐NAME (20 mg kg−1) was administered. In both conditions the muscle was pump‐perfused with constantly elevated blood flow , at a level measured during a preliminary contraction trial with spontaneous self‐perfused. A vasodilatory drug was also infused. Arterial and venous O2 concentrations were determined at rest and at 5–7 s intervals during the transition. was calculated by Fick's principle. Muscle biopsies were obtained at rest and during contractions. Muscle force was measured continuously. Phosphocreatine hydrolysis and the calculated substrate level phosphorylation were slightly (but not significantly) lower in l‐NAME than in CTRL. Significantly (P < 0.05) less fatigue was found in l‐NAME versus CTRL. The time delay (TDf) and the time constant (τf) of the ‘fundamental’ component of kinetics were not significantly different between CTRL (TDf 7.2 ± 1.2 s; and τf 10.6 ± 1.3, ±s.e.m.) and l‐NAME (TDf 9.3 ± 0.6; and τf 10.4 ± 1.0). Contrary to our hypothesis, NOS inhibition did not accelerate muscle kinetics. The down‐regulation of mitochondrial respiration by NO does not limit the kinetics of adjustment of oxidative metabolism at exercise onset.
The effect of low protein diet in pregnancy on the development of brain metabolism in rat offspring
Authors: Gallagher E. A. L. , Newman J. P. , Green L. R. , Hanson M. A.
Published: August 2005

The effect of maternal low protein diet in pregnancy on the function of offspring cerebral cytochrome c oxidase (CcO) was investigated in vitro immediately before and after birth, using fetal and neonatal rat pup forebrain tissue. Pregnant rat dams were fed either a control (C, 18% casein n= 22) or low protein (LP, 9% casein n= 14) diet. Cerebral tissues were harvested from pups the day before (E21) and after (P1) birth. A Clarke electrode chamber was used to determine O2 consumption in brain tissue homogenate, under baseline conditions with and without the mitochondrial electron transport chain inhibitor myxothiazol and in the presence of incremental doses of the electron donor N',N',N',N'‐tetramethyl‐p‐phenylenediamide (TMPD) with myxothiazol. Maximal stimulated CcO activity was less in LP versus C pups at both E21 (P < 0.001) and P1 (P < 0.05). At E21 only, sensitivity to electron flux (pEC50) was greater (P < 0.001) in LP compared to C offspring. In addition, was reduced and pEC50 was greater after birth (i.e. P1 versus E21) in C (P < 0.001) but not in LP pups. This is the first report of the effects of maternal dietary imbalance in pregnancy on offspring cerebral metabolic function. The effects may form part of a developmental adaptive response to reduce energy consumption and promote perinatal survival, or to confer advantage in a postnatal environment predicted to be nutritionally poor.
Nitric oxide blunts the endothelin‐mediated pulmonary vasoconstriction in exercising swine
Authors: Houweling Birgit , Merkus Daphne , Dekker Marjolein M. D. , Duncker Dirk J.
Published: August 2005

We have previously shown that vasodilators and vasoconstrictors that are produced by the vascular endothelium, including nitric oxide (NO), prostanoids and endothelin (ET), contribute to the regulation of systemic and pulmonary vascular tone in swine, in particular during treadmill exercise. Since NO and prostanoids can modulate the release of ET, and vice versa, we investigated the integrated endothelial control of pulmonary vascular resistance in exercising swine. Specifically, we tested the hypothesis that increased NO and prostanoid production during exercise limits the vasoconstrictor influence of ET, so that loss of these vasodilators results in exaggerated ET‐mediated vasoconstriction during exercise. Fifteen instrumented swine were exercised on a treadmill at 0–5 km h−1 before and during ETA/ETB receptor blockade (tezosentan, 3 mg kg−1i.v.) in the presence and absence of inhibition of NO synthase (Nω‐nitro‐l‐arginine, 20 mg kg−1i.v.) and/or cyclo‐oxygenase (indometacin, 10 mg kg−1i.v.). In the systemic circulation, ET receptor blockade decreased vascular resistance at rest, which waned with increasing exercise intensity. Prior inhibition of either NO or prostanoid production augmented the vasodilator effect of ET receptor blockade, and these effects were additive. In contrast, in the pulmonary bed, ET receptor blockade had no effect under resting conditions, but decreased pulmonary vascular resistance during exercise. Prior inhibition of NO synthase enhanced the pulmonary vasodilator effect of ET receptor blockade, particularly during exercise, whereas inhibition of prostanoids had no effect, even after prior NO synthase inhibition. In conclusion, endogenous endothelin limits pulmonary vasodilatation in response to treadmill exercise. This vasoconstrictor influence is blunted by NO but not by prostanoids.
Anandamide elicits an acute release of nitric oxide through endothelial TRPV1 receptor activation in the rat arterial mesenteric bed
Authors: Poblete Inés M. , Orliac María Luz , Briones René , Adler‐Graschinsky Edda , Huidobro‐Toro J. Pablo
Published: August 2005

In the isolated rat mesenteric bed, the 1 min perfusion with 100 nm anandamide, a concentration that did not evoke vasorelaxation, elicited an acute release of 165.1 ± 9.2 pmol nitric oxide (NO) that was paralleled by a 2‐fold increase in cGMP tissue levels. The rise in NO released was mimicked by either (R)‐(+)‐methanandamide or the vanilloid receptor agonists resiniferatoxin and (E)‐capsaicin but not by its inactive cis‐isomer (Z)‐capsaicin. The NO release elicited by either anandamide or capsaicin was reduced by the TRPV1 receptor antagonists 5′‐iodoresiniferatoxin, SB 366791 and capsazepine as well as by the cannabinoid CB1 receptor antagonists SR 141716A or AM251. The outflow of NO elicited by anandamide and capsaicin was also reduced by endothelium removal or NO synthase inhibition, suggesting the specific participation of endothelial TRPV1 receptors, rather than the novel endothelial TRPV4 receptors. Consistently, RT‐PCR showed the expression of the mRNA coding for the rat TRPV1 receptor in the endothelial cell layer, in addition to its expression in sensory nerves. The participation of sensory nerves on the release of NO was precluded on the basis that neonatal denervation of the myenteric plexus sensory nerves did not modify the pattern of NO release induced by anandamide and capsaicin. We propose that low concentrations of anandamide, devoid of vasorelaxing effects, elicit an acute release of NO mediated predominantly by the activation of endothelial TRPV1 receptors whose physiological significance remains elusive.
Median preoptic neurones projecting to the hypothalamic paraventricular nucleus respond to osmotic, circulating Ang II and baroreceptor input in the rat
Authors: Stocker Sean D. , Toney Glenn M.
Published: August 2005

The present study sought to determine whether individual neurones of the median preoptic nucleus (MnPO) with axonal projections to the hypothalamic paraventricular nucleus (MnPO‐PVN) respond to osmotic, circulating angiotensin II (Ang II), and baroreceptor stimulation. Hypertonic NaCl (0.75 or 1.5 osmol l−1) or Ang II (150 ng) was injected into the internal carotid artery (ICA). Baroreceptor stimulation was performed byi.v.injection of phenylephrine or sodium nitroprusside to increase or decrease arterial blood pressure, respectively. Of 65 MnPO neurones, 50 units were antidromically activated from the PVN with an average onset latency of 11.3 ± 0.7 ms. Only 9.5% of MnPO‐PVN neurones were antidromically activated from the PVN bilaterally. Type I MnPO‐PVN neurones (n= 14) responded to osmotic but not Ang II stimulation. In 79% (11/14) of these type I neurones, the response was an increase in cell discharge. Type II MnPO‐PVN neurones (n= 7) displayed a significant increase in cell discharge in response to ICA injection of Ang II but not hypertonic NaCl. Type III MnPO‐PVN neurones (n= 16) responded to both ICA injection of hypertonic NaCl and Ang II. In 88% (14/16) of type III neurones, osmotic and Ang II stimulation each increased cell discharge. Type IV MnPO‐PVN neurones (n= 13) displayed no change in cell discharge in response to ICA injection of hypertonic NaCl or Ang II. Baroreceptor stimulation altered the discharge in subpopulations of type I, II and III MnPO‐PVN neurones (43–63% depending on neuronal type). Only one MnPO‐PVN neurone responded solely to baroreceptor stimulation (type IV). In addition, a subset of type I, II and III neurones displayed a significant correlation with sympathetic nerve activity and/or the cardiac cycle. These findings suggest that a significant population of MnPO‐PVN neurones respond to osmotic and circulating Ang II stimulation and thereby represents a neural substrate through which neurohumoral inputs are integrated within the forebrain lamina terminalis.
Numerical
and Experimental Investigation of a Multiple Air Jet Cooling System for Application in a Solar
Thermal Receiver
Authors: Röger M. , Buck R. , Müller-Steinhagen H.
Published: August 2005

The transparent quartz glass window of a high temperature solar receiver (1000°C air outlet temperature, 15bars) has to be protected from overheating. The window is an axially symmetric part that can be approximated by a hemisphere with a cylindrical extension (diameter 0.31m, height 0.42m). The cooling is accomplished by impinging several air jets onto the concave window surface. Due to concentrated solar radiation, the air supply nozzles can only be installed at the circumference of the cylindrical extension. Symmetric configurations with six or nine nozzles, equally distributed around the window circumference, are examined. A second configuration generates a swirl in the window cavity by inclining the nozzles. In a third, asymmetric configuration, only nozzles on one side are simultaneously charged with mass flow, while a spatial homogenization of heat transfer is reached by periodically modulating the air flows with time. Computational fluid dynamics (CFD) calculations and laboratory measurements of the heat transfer have been carried out. In the performed 3-D simulations, the realizable k-ε model, the k-ω model, and the SST-k-ω model are compared. For measuring the heat transfer coefficient, a periodic-transient measurement technique with high spatial resolution is used. For the application of cooling of the solar receiver window, the jet cooling system with periodically modulated air flows is identified as the best solution.
Fully Developed Nucleate Boiling in Narrow Vertical Channels
Authors: Lakshminarasimhan M. S. , Lu Q. , Chin Y. , Hollingsworth D. K. , Witte Larry C.
Published: August 2005

Experiments were performed to investigate nucleate flow boiling and incipience in a vertical flow channel, 20mmwide×357mmlong, with one wall heated uniformly and others approximately adiabatic. Three channel spacings, 2, 1 and 0.5mm, were investigated. Initially subcooled R-11 flowed upward through the channel; the mass flux varied from 60to4586kg∕(m2s), and the inlet pressure ranged up to 0.20MPa. Liquid crystal thermography was used to measure distributions of surface temperature from which the heat transfer coefficients on the heated surface were calculated. Fully developed saturated nucleate boiling was correlated well by a modification of Kandlikar’s technique.
Performance Evaluation of Liquid Flow With PCM Particles in Microchannels
Authors: Xing K. Q. , Tao Y.-X. , Hao Y. L.
Published: August 2005

A two-phase, non thermal equilibrium-based model is applied to the numerical simulation of laminar flow and heat transfer characteristics of suspension with microsize phase-change material (PCM) particles in a microchannel. The model solves the conservation of mass, momentum, and thermal energy equations for liquid and particle phases separately. The study focuses on the parametric study of optimal conditions where heat transfer is enhanced with an increase in fluid power necessary for pumping the two-phase flow. The main contribution of PCM particles to the enhancement of heat transfer in a microsize tube is to increase the effective thermal capacity and utilize the latent heat effect under the laminar flow condition. An effectiveness factor εeff is defined to evaluate the heat transfer enhancement compared to the single-phase flow heat transfer and is calculated under different wall heat fluxes and different Reynolds numbers. The comparison is also made to evaluate the performance index, i.e., the ratio of total heat transfer rate to fluid flow power (pressure drop multiplied by volume flow rate) between PCM suspension flow and pure water single-phase flow. The results show that for a given Reynolds number, there exists an optimal heat flux under which the εeff value is the greatest. In general, the PCM suspension flow with phase change has a significantly higher performance index than the pure-fluid flow. The comparison of the model simulation with the limited experimental results for a MCPCM suspension flow in a 3mmdia tube reveals the sensitivity of wall temperature distribution to the PCM supply temperature and the importance of characterizing the phase change region for a given tube length.
Hybrid Method to Calculate Direct Exchange Areas Using the Finite Volume Method and Midpoint Intergration
Authors: Tian Weixue , Chiu Wilson K. S.
Published: August 2005

This paper presents a hybrid method to calculate direct exchange areas for an infinitely long black-walled rectangular enclosure. The hybrid method combines the finite volume method (FVM) with the midpoint integration scheme. Direct numerical integration of direct exchange areas for adjacent and overlapping zones is difficult because of singularities in the integrand. Therefore, direct exchange areas of adjacent and overlapping zones are calculated using the FVM. Direct exchange areas of nonadjacent zones are calculated by the efficient midpoint integration scheme. Thus, direct exchange areas in an infinitely long enclosure can be obtained with both efficiency and accuracy. Volume-volume direct exchange areas of zones with various aspect ratios and optical thickness have been calculated and compared to exact solutions, and satisfactory results are found.
Effect of Buoyancy on Heat Transfer in Supercritical Water Flow in a Horizontal Round Tube
Authors: Bazargan Majid , Fraser Daniel , Chatoorgan Vijay
Published: August 2005

Heat transfer to supercritical water and buoyancy∕natural convection effects are becoming increasingly important areas of research due to current trends in nuclear reactor design and supercritical water oxidation facilities. A pilot-scale supercritical water oxidation loop was constructed at the University of British Columbia. For this work, the facility was used to study the relative importance of buoyancy effects on supercritical water flowing in a horizontal pipe. Local heat transfer coefficients at the top and bottom surfaces of the horizontal test section were systematically measured over a wide range of conditions at supercritical pressures between 23 to 27 MPa, uniform heat fluxes were up to 310kW∕m2, and the mass flux ranged from 330 to 1230kg∕m2s. It was found that neglecting buoyancy effects could cause large discrepancies between the predictions of available empirical correlations and the experimental data. The data was used to assess available criteria for the buoyancy-free region during horizontal supercritical fluid flows. The criterion of Petukhov and Polyakov, which, for the range of parameters in this study, was found to be accurate in predicting the onset of buoyancy effects. The experimental investigation is confined to supercritical flows with heat addition only. Hence, no heat loss conditions at supercritical temperatures were investigated.
Effects of Wall Rotation on Heat Transfer to Annular Turbulent Flow: Outer Wall Rotating
Authors: Lee Joon Sang , Xu Xiaofeng , Pletcher Richard H.
Published: August 2005

Simulations were conducted for air flowing upward in a vertical annular pipe with a rotating outer wall. Simulations concentrated on the occurrence of laminarization and property variations for high heat flux heat transfer. The compressible filtered Navier-Stokes equations were solved using a second-order accurate finite volume method. Low Mach number preconditioning was used to enable the compressible code to work efficiently at low Mach numbers. A dynamic subgrid-scale stress model accounted for the subgrid-scale turbulence. When the outer wall rotated, a significant reduction of turbulent kinetic energy was realized near the rotating wall and the intensity of bursting appeared to decrease. This modification of the turbulent structures was related to the vortical structure changes near the rotating wall. It has been observed that the wall vortices were pushed in the direction of rotation and their intensity increased near the nonrotating wall. The consequent effect was to enhance the turbulent kinetic energy and increase the Nusselt number there.
Effects Of Dimple Depth on Channel Nusselt Numbers and Friction Factors
Authors: Burgess N. K. , Ligrani P. M.
Published: August 2005

Experimental results, measured on dimpled test surfaces placed on one wall of different rectangular channels, are given for a ratio of air inlet stagnation temperature to surface temperature of approximately 0.94, and Reynolds numbers based on channel height from 9940 to 74,800. The data presented include friction factors, local Nusselt numbers, spatially averaged Nusselt numbers, and globally averaged Nusselt numbers. The ratios of dimple depth to dimple print diameter δ∕D are 0.1, 0.2, and 0.3 to provide information on the influences of dimple depth. The ratio of channel height to dimple print diameter is 1.00. At all Reynolds numbers considered, local spatially resolved and spatially averaged Nusselt number augmentations increase as dimple depth increases (and all other experimental and geometric parameters are held approximately constant). These are attributed to (i) increases in the strengths and intensity of vortices and associated secondary flows ejected from the dimples, as well as (ii) increases in the magnitudes of three-dimensional turbulence production and turbulence transport. The effects of these phenomena are especially apparent in local Nusselt number ratio distributions measured just inside of the dimples and just downstream of the downstream edges of the dimples. Data are also presented to illustrate the effects of Reynolds number and streamwise development for δ∕D=0.1 dimples. Significant local Nusselt number ratio variations are observed at different streamwise locations, whereas variations with the Reynolds number are mostly apparent on flat surfaces just downstream of individual dimples.
Time reversal processing for source location in an urban environment
Authors: Albert Donald G. , Liu Lanbo , Moran Mark L.
Published: August 2005

A simulation study is conducted to demonstrate in principle that time reversal processing can be used to locate sound sources in an outdoor urban area with many buildings. Acoustic pulse propagation in this environment is simulated using a two-dimensional finite difference time domain (FDTD) computation. Using the simulated time traces from only a few sensors and back propagating them with the FDTD model, the sound energy refocuses in the vicinity of the true source location. This time reversal numerical experiment confirms that using information acquired only at non-line-of-sight locations is sufficient to obtain accurate source locations in a complex urban terrain.
The transmission loss of curved laminates and sandwich composite panels
Authors: Ghinet Sebastian , Atalla Noureddine , Osman Haisam
Published: August 2005

The paper describes a model to calculate the transmission loss of both curved laminate and sandwich composite panels within statistical energy analysis (SEA) context. The vibro-acoustic problem is developed following a wave approach based on a discrete lamina description. Each lamina is considered to consist of membrane, bending, transverse shearing and rotational inertia behaviors. Moreover, the orthotropic ply angle of each lamina is considered. Using such a discrete lamina description, the dispersion behaviors of the panel are correctly represented. Using the dispersion curves, the radiation efficiency, the modal density, as well as, the nonresonant and the resonant transmission are computed. Moreover, expression for the evaluation of the ring frequency and the critical frequencies of such panels is given. The described model is shown to handle accurately, both laminate and sandwich composite shells. Additionally, a transmission loss test is presented to confirm the validity of the presented model.
A space–time filtered gradient method for detecting directions of echoes and transient sounds
Authors: Henderson Terry L. , Brudner Terry J.
Published: August 2005

The gradient vector (e.g., of the acoustic pressure) indicates the direction to the source of a wave, but it is easily corrupted by interference from other directions. However the gradient concept, even for higher orders, can be applied rigorously to a beamforming aperture that shields against interference, thereby allowing precise determination of the direction of sound echoes or emissions, especially for very brief, broadband transient sounds. In this treatment there is no gradient sensor per se; the aperture weighting supplants that function. Various geometric shapes can be used as apertures, but simple plates are often best, and the required weightings can be realized by patterned electrodes. The method is shown to be a natural extension of earlier techniques and inventions, and useful interpretations and generalizations are provided, such as compound and steered apertures, instantantly re-steerable nulls, and an equivalence to tracking acoustic particle motion after acoustical shielding from interference. There are two stages: aperture signal extraction, and ratio processing based upon Watson–Watt concepts, for which statistically based formulas are useful. In-water test results are provided.
A state-space coupling method for fluid-structure interaction analysis of plates
Authors: Li Sheng
Published: August 2005

A state-space coupling method is presented for the direct solution of fluid-loaded natural frequencies and mode shapes of plates. This method expands the frequency-dependent term in the Rayleigh integral in a power series on circular frequency. After factoring out the frequency term from the integrands, integration involved in setting up the acoustic impedance coefficient matrices is confined to a frequency-independent part. The acoustic impedance coefficient matrices are therefore frequency-independent and can be coupled directly with the structural matrix into a canonical state-space form to yield the fluid-loaded modes via the direct eigenvalue analysis. A fluid-loaded stiffened plate is involved to demonstrate the method. Numerical results of the fluid-loaded natural frequencies, mode shapes, and modal damping ratios are given to show the efficacy of the state-space coupling method.
Correcting the use of ensemble averages in the calculation of harmonics to noise ratios in voice signals
Authors: Ferrer Carlos A. , González Eduardo , Hernández-Díaz María E.
Published: August 2005

A correcting formula for the estimation of harmonics-to-noise ratios (HNR) based on ensemble-averaging techniques is derived. The original method yields a biased approximation which is more accurate as the number of averaged pulses (N) increases. However, the method treats gradual waveform changes incorrectly as noise, which is worsened for large values of N. The obtained formula allows the use of as few averaged pulses as desired, while allowing the complete removal of the bias from the estimate of HNR.
Pitch shifts for complex tones with unresolved harmonics and the implications for models of pitch perception
Authors: Watkinson Rebecca K. , Plack Christopher J. , Fantini Deborah A.
Published: August 2005

Complex tone bursts were bandpass filtered, 22nd–30th harmonic, to produce waveforms with five regularly occurring envelope peaks (“pitch pulses”) that evoked pitches associated with their repetition period. Two such tone bursts were presented sequentially and separated by an interpulse interval (IPI). When the IPI was varied, the pitch of the whole sequence was shifted by between +2% and −5%. When the IPI was greater than one period, little effect was seen. This is consistent with a pitch mechanism employing a long integration time for continuous stimuli that resets in response to temporal discontinuities of greater than about one period of the waveform. Similar pitch shifts were observed for fundamental frequencies from 100to250Hz. The pitch shifts depended on the IPI duration relative to the period of the complex, not on the absolute IPI duration. The pitch shifts are inconsistent with the autocorrelation model of Meddis and O’Mard [J. Acoust. Soc. Am. 102, 1811–1820 (1997)], although a modified version of the weighted mean-interval model of Carlyon et al. [J. Acoust. Soc. Am. 112, 621–633 (2002)] was successful. The pitch shifts suggest that, when two pulses occur close together, one of the pulses is ignored on a probabilistic basis.
Perception of dissonance by people with normal hearing and sensorineural hearing loss
Authors: Tufts Jennifer B. , Molis Michelle R. , Leek Marjorie R.
Published: August 2005

The purpose of this study was to determine whether the perceived sensory dissonance of pairs of pure tones (PT dyads) or pairs of harmonic complex tones (HC dyads) is altered due to sensorineural hearing loss. Four normal-hearing (NH) and four hearing-impaired (HI) listeners judged the sensory dissonance of PT dyads geometrically centered at 500 and 2000Hz, and of HC dyads with fundamental frequencies geometrically centered at 500Hz. The frequency separation of the members of the dyads varied from 0Hz to just over an octave. In addition, frequency selectivity was assessed at 500 and 2000Hz for each listener. Maximum dissonance was perceived at frequency separations smaller than the auditory filter bandwidth for both groups of listners, but maximum dissonance for HI listeners occurred at a greater proportion of their bandwidths at 500Hz than at 2000Hz. Further, their auditory filter bandwidths at 500Hz were significantly wider than those of the NH listeners. For both the PT and HC dyads, curves displaying dissonance as a function of frequency separation were more compressed for the HI listeners, possibly reflecting less contrast between their perceptions of consonance and dissonance compared with the NH listeners.
Application of the phase gradient method to the study of the resonances of a water-loaded anisotropic plate
Authors: Guénégou L. , Lenoir O.
Published: August 2005

The phase gradient method is applied to cubic and orthotropic plates. It consists in simply obtaining the positions and the widths of their frequency and angular resonances from the plots of the frequency and angular derivatives of the phase of the reflection coefficient of the immersed plate. There is a good match with the results obtained from the calculation of the modes of the immersed plate in the corresponding complex planes. Moreover, these two derivatives allow us to obtain frequency and angular quality factors.
On the measurement of the Young’s modulus of small samples by acoustic interferometry
Authors: Simonetti F. , Cawley P. , Demčenko A.
Published: August 2005

This paper describes and validates an interferometric technique for the measurement of the Young’s modulus of limited size samples. The technique is a generalization of the torsional guided wave interferometry introduced in a previous paper [Simonetti and Cawley, J. Acoust. Soc. Am. 115, 157–164 (2004)] for the characterization of the shear properties of soft materials. The method is based on the transmission of the fundamental longitudinal guided mode through a sample clamped between two buffer rods. The main difference with other interferometric techniques is the use of a delay line placed between the sample and one of the buffer rods. While with conventional interferometry the sample length needs to be larger than half of the shortest wavelength which can be propagated through the sample, the introduction of the delay line removes this limitation enabling the characterization of very small samples (compared to the wavelength). In addition, this method is suitable for testing highly attenuative materials which can be cut into thin specimens so reducing the energy absorption as the acoustic signal propagates through the sample. The principle of the method is discussed and measurements on a variety of specimens are presented. Results for long material specimens tested without delay line and short samples of the same material tested with the delay line agree within 1%. Moreover, measurements are in good agreement with results obtained from conventional methods and literature.
Evaluating models of vowel perception
Authors: Molis Michelle R.
Published: August 2005

There is a long-standing debate concerning the efficacy of formant-based versus whole spectrum models of vowel perception. Categorization data for a set of synthetic steady-state vowels were used to evaluate both types of models. The models tested included various combinations of formant frequencies and amplitudes, principal components derived from excitation patterns, and perceptually scaled LPC cepstral coefficients. The stimuli were 54 five-formant synthesized vowels that had a common F1 frequency and varied orthogonally in F2 and F3 frequency. Twelve speakers of American English categorized the stimuli as the vowels ∕ɪ∕, ∕ʊ∕, or ∕ɝ∕. Results indicate that formant frequencies provided the best account of the data only if nonlinear terms, in the form of squares and cross products of the formant values, were also included in the analysis. The excitation pattern principal components also produced reasonably accurate fits to the data. Although a wish to use the lowest-dimensional representation would dictate that formant frequencies are the most appropriate vowel description, the relative success of richer, more flexible, and more neurophysiologically plausible whole spectrum representations suggests that they may be preferred for understanding human vowel perception.
Vowel perception by noise masked normal-hearing young adults
Authors: Richie Carolyn , Kewley-Port Diane , Coughlin Maureen
Published: August 2005

This study examined vowel perception by young normal-hearing (YNH) adults, in various listening conditions designed to simulate mild-to-moderate sloping sensorineural hearing loss. YNH listeners were individually age- and gender-matched to young hearing-impaired (YHI) listeners tested in a previous study [Richie et al., J. Acoust. Soc. Am. 114, 2923–2933 (2003)]. YNH listeners were tested in three conditions designed to create equal audibility with the YHI listeners; a low signal level with and without a simulated hearing loss, and a high signal level with a simulated hearing loss. Listeners discriminated changes in synthetic vowel tokens /ɪ e ε ʌ æ/ when F1 or F2 varied in frequency. Comparison of YNH with YHI results failed to reveal significant differences between groups in terms of performance on vowel discrimination, in conditions of similar audibility by using both noise masking to elevate the hearing thresholds of the YNH and applying frequency-specific gain to the YHI listeners. Further, analysis of learning curves suggests that while the YHI listeners completed an average of 46% more test blocks than YNH listeners, the YHI achieved a level of discrimination similar to that of the YNH within the same number of blocks. Apparently, when age and gender are closely matched between young hearing-impaired and normal-hearing adults, performance on vowel tasks may be explained by audibility alone.
Reflection of a spherical wave by acoustically hard, concave cylindrical walls based on the tangential plane approximation
Authors: Yamada Yoshinari , Hidaka Takayuki
Published: August 2005

The tangential plane approximation (TPA) is introduced to investigate the spherical wave reflection from smooth concave cylindrical walls, and as a practical calculation scheme, asymptotic expression of the reflected sound from that surface with a relatively large dimension is derived. The physical condition under which TPA holds is derived for the spherical wave incidence; moreover, the essential properties of the reflected sound from the curved walls, which cannot be treated by the geometrical acoustics, are discussed through the numerical calculation for infinitely long cylinders. A formula of the reflection factor of the two-dimensional curved surface is obtained for the purpose of the room acoustical design. This formula coincides with that based on the geometrical acoustics when the frequency is infinitely high.
Transducer hysteresis contributes to “stimulus artifact” in the measurement of click-evoked otoacoustic emissions
Authors: Kapadia Sarosh , Lutman Mark E. , Palmer Alan R.
Published: August 2005

Click-evoked otoacoustic emissions from the human ear are typically several orders of magnitude smaller than the stimuli that elicit them—a measurement technique that attempts to cancel the stimulus signal from the recorded waveform is therefore typically employed. In practice, an imperfect cancellation of the stimulus is achieved, leaving a “stimulus artifact” that obscures the early part of the emission. Input-output nonlinearities of the transducers used in recording emissions are acknowledged as one source of the stimulus artifact. Here an additional source of this artifact, related to hysteresis in the magnetic “receivers” (loudspeakers) used in such recordings, is identified and discussed.