bluuebunny/crossref_metadata_2025 huggingface dataset:
Children's Gender‐ and Ethnicity‐based Reasoning about Foods
Authors: Lam Virginia , Leman Patrick
Published: June 2008

This article reports two studies that investigated the ways in which children use gender and ethnicity for making judgments about food choice. In Study 1, White and Asian 5‐ to 10‐year‐olds (M = 7.37) were asked to rate how much they and others would like novel non‐stereotyped foods. White children inferred that girls and White others would like the foods more than boys and Asian others would. An ‘ethnocentric’ pattern was found where children inferred that ethnic in‐group others’ food‐liking would be more similar to their own compared with ethnic out‐group others. These patterns were replicated with adults. In Study 2, a larger range of foods was used to assess White, Black, and Asian 3‐ to 8‐year‐olds (M = 5.63), followed by gender and ethnic categorization and constancy tasks. Children from five to six years used ethnicity‐based reasoning, which was influenced by their ability to categorize themselves and others by ethnicity. The role of social categories in food choice is discussed in the light of theories and research in category‐based reasoning.
Self‐protective Optimism: Children's Biased Beliefs about the Stability of Traits
Authors: Diesendruck Gil , Lindenbaum Tali
Published: June 2008

Studies indicate that children believe that positive behaviors are more likely than negative ones to remain stable across time and situations. The present study assessed whether children hold such optimism equally regarding their own vs. others' behavioral patterns. Thirty five‐year‐olds answered questions about the extent to which they viewed themselves as having various positively, neutrally, and negatively valued behavioral patterns. An experimenter then asked children about the extent to which behavioral patterns that children thought they had would remain stable in themselves and in others, and the extent to which behavioral patterns that they did not think they had would remain stable in others. We found that children gave higher stability ratings for positive behaviors in themselves than in others, and the opposite regarding negative behaviors. This self‐protective optimism is discussed vis‐à‐vis the relationship between children's beliefs about traits and their behaviors and motivations.
Children's Reasoning about Lie‐telling and Truth‐telling in Politeness Contexts
Authors: Heyman Gail D. , Sweet Monica A. , Lee Kang
Published: June 2008

Children's reasoning about lying and truth‐telling was examined among participants ages 7–11 (total N = 181) with reference to conflicts between being honest and protecting the feelings of others. In Study 1, participants showed different patterns of evaluation and motivational inference in politeness contexts vs. transgression contexts: in politeness contexts, they rated lie‐telling more favorably and were far more likely to assume that motives were prosocial. In Study 2, participants evaluated lie‐telling more positively and truth‐telling more negatively in politeness contexts, especially when they focused on the implications of the statements for others instead of whether the statements were true or false.
The transmission of business cycles Implications for EMU enlargement1
Authors: Artis Michael J. , Fidrmuc Jarko , Scharler Johann
Published: June 2008

We show that countries characterized by large bilateral trade and financial flows tend to have more correlated business cycles. However, we also find that countries with divergent fiscal policies and highly regulated labour markets are subject to idiosyncratic cycles. Applying these results to the new member states of the EU weakens the optimistic view towards the monetary integration of these countries into the euro area, which is frequently found in the literature. Although our results suggest that extensive trade and financial linkages are likely to result in further increases in business cycle correlation, an increase in labour market regulation and the pursuit of national fiscal policies may result in a counteracting effect.
Does access to credit improve productivity?  Evidence from Bulgaria1
Authors: Gatti Roberta , Love Inessa
Published: June 2008

Although it is widely accepted that financial development is associated with higher growth, the evidence on the channels through which credit affects growth at the microeconomic level is scant. Using data from a cross‐section of Bulgarian firms, we estimate the impact of access to credit, as proxied by indicators of whether firms have access to a credit line or overdraft facility, on productivity. To overcome potential omitted variable bias of Ordinary Least Squares (OLS) estimates, we use information on firms’ past growth to instrument for access to credit. We find credit to be positively and strongly associated with TFP. These results are robust to a wide range of robustness checks.
On the Measurement of Market Power in the Banking Industry
Authors: Delis Manthos D. , Staikouras K. Christos , Varlagas Panagiotis T.
Published: June 2008

Abstract:  This paper compares the estimates of the two most widely used non‐structural models for market power measurement in banking, namely the conduct parameter method and the revenue test, as applied to three panels of Greek, Latvian and Spanish banks over the period 1993–2004. We also propose a dynamic reformulation of these models within a panel data context, in order to address possible statistical problems associated with the dynamic nature of bank‐level data. The results suggest that both static methods provide lower estimates of market power relative to their dynamic counterparts. Therefore, the inclusion of some dynamics in the models, even though it increased estimation complexity, helped to reveal some collusive behavior of banks.
Financial Statement Information, the Prediction of Book Return on Owners' Equity and Market Efficiency: The Swedish Case
Authors: Skogsvik Stina
Published: June 2008

Abstract:  Using Swedish data, this study investigates whether financial statement information can be used to predict changes in the medium‐term book return on owners' equity and subsequently evaluates the performance of trading strategies based on such predictions. A univariate prediction model based on the past book return has higher prediction accuracy than more elaborate models that include additional accounting numbers. The main trading strategy generates a hedge position return of 29% over a three‐year holding period. Interestingly, most of the return is attributable to the long position. However, the results are found to be sensitive to the choice of return metric.
Intravenous Lidocaine Infusion for the Treatment of Post‐Acoustic Neuroma Resection Headache: A Case Report
Authors: Schere Daniel , Silberstein Stephen D.
Published: June 2008

Presentation of a case report of a 47‐year‐old male with a post‐acoustic neuroma resection intractable headache responding to intravenous lidocaine infusion. The patient was then switched to mexiletine, with good response.
The First 5 Minutes After Greater Occipital Nerve Block
Authors: Young William , Cook Brianna , Malik Shahram , Shaw James , Oshinsky Michael
Published: June 2008

We performed greater occipital nerve blocks on 24 migraineurs with unilateral migraine and trigeminal nerve distribution allodynia. Using a visual analog scale for migraine pain, brush allodynia in the trigeminal nerve distribution and photophobia were reduced 64%, 75%, and 67%, respectively, after 5 minutes. Allodynia improved faster than headache. The results of this study suggest that greater occipital nerve blocks initiate an inhibitory process that shuts down several symptom generators.
Ocular Findings in Pediatric Deaths Under 2 Years of Age (1994–2004)
Authors: Arredondo Jorge L. , Fernandes John R. , Rao Chitra
Published: June 2008

Abstract:  Our purpose is to highlight novel ocular findings of 102 forensic pediatric cases under 2 years of age who die suddenly. Forensic information, grossing, and microscopic eye protocol was followed. The most common diagnosis was Sudden Infant Death Syndrome (SIDS) (57/102). Novel cytoid bodies were present in the retina of 72/102 cases and they were located predominantly 90% (65/72) at the anterior part of the retina (p < 0.001). Of the SIDS cases, 85% (47/57) showed the presence of cytoid bodies, and among all diagnosis, SIDS was the most associated with cytoid bodies (p = 0.003). A second observation was extramedullary hematopoiesis (EMH) identified in 35/102 cases and 22 of the 57 SIDS cases. The most frequent EMH location was the choroids (29/35). This study is the first to demonstrate the presence of cytoid bodies and extramedullary hematopoiesis in the retinas of SIDS cases and children who die suddenly from other causes.
Medfly populations differ in diel and age patterns of sexual signalling
Authors: Diamantidis Alexandros D. , Papadopoulos Nikos T. , Carey James R.
Published: June 2008

Insect populations may differ in several life history traits, including behavioural ones such as sexual signalling. We tested whether male Mediterranean fruit fly (medlfy),Ceratitis capitata(Wiedemann) (Diptera: Tephritidae), populations obtained from geographically isolated areas exhibit differences in quantitative and qualitative aspects of male sexual signalling. Male sexual signalling was studied in four medfly populations (originating from Brazil, Portugal, Kenya, and Greece) under identical laboratory conditions (25 °C, 60% r.h., and L14:D10). The four populations had been reared for one generation in the laboratory. Sexual signalling was studied in the F1progeny that were fed one of two diets (yeast hydrolysate plus sugar or sugar only). On both diets, the four populations differed significantly in the progress of maturity (indicated by the average number of males exhibiting sexual signalling) and in the quantity of signalling after attaining maturity. Yeast availability significantly increased sexual signalling; however, it had a different impact on the quantity of signalling in the different populations. A bi‐modal pattern of sexual signalling, with one peak at approximately 08:00–09:00 hours and the second at approximately 13:00–14:00 hours, was recorded for all populations and diets. However, quantitative differences among the populations within the ‘sexually active’ period of the day resulted in significant differences in the daily pattern of sexual signalling. The significance of these findings for understanding adaptations of geographically isolated medfly populations to different ecosystems, as well as its practical importance for the application of the sterile insect technique againstC. capitata, is discussed.
Ovarian response to resource availability in female Rhagoletis indifferens
Authors: Senger Susan E. , Roitberg Bernard D. , Thistlewood Howard M. A.
Published: June 2008

Fitness trade‐offs in behavioural ecology theory suggest that the costs associated with dispersal can impact reproductive output, but evidence of dispersal‐reproduction trade‐offs is often lacking. We present evidence of Rhagoletis indifferens Curran (Diptera: Tephritidae) developing its egg load in response to host availability [Prunus avium L. (Rosaceae)] and link this to our previous work on flight behaviour through the common methodology of these two studies. We replicated the study design from the flight mill experiment, such that females were maintained in one of six possible treatments combining two factors: social interactions (crowded vs. isolated) and resources (food = food only; leaf = food + leaf; and cherry = food + leaf + fruit), and then dissected the females to determine egg load. Egg counts varied significantly with ‘crowded’ females and those in the ‘cherry’ resource treatments producing the most mature eggs. Although the average mature egg count for females from the ‘leaf’ and ‘food’ resource treatments was similar, these two groups differed in the proportion of females that produced no mature eggs at all. No significant interaction terms between the factors tested were generated. We conclude that the effect of social interactions and resources on the maturation of eggs is additive in R. indifferens. These results support those of an earlier flight mill experiment and provide evidence that egg load may trade off with dispersal ability in R. indifferens.
Nasal high‐frequency ventilation for premature infants
Authors: Colaizy Tarah T , Younis Usama MM , Bell Edward F , Klein Jonathan M
Published: June 2008

Aim: To assess the use of nasal high‐frequency ventilation (HFV) to provide noninvasive ventilatory support for very low birthweight (VLBW) infants.

Study Design: VLBW infants, >7 days of age on nasal continuous positive airway pressure (CPAP), were placed on nasal HFV for 2 h using the Infant Star high‐frequency ventilator (Mallinckrodt, Inc., St. Louis, MO, USA). Mean airway pressure was set to equal the previous level of CPAP, and amplitude was adjusted to obtain chest wall vibration. Capillary blood was sampled before starting HFV and after 2 h to determine change in pH and partial pressure of carbon dioxide (pCO2).

Results: Fourteen subjects were studied, 10 males and 4 females. Gestational age was 26–30 weeks (median 27). Age at study was 18–147 days (median 30). Median birth weight was 955 g; median weight at study was 1605 g. Nasal CPAP pressure was 4–7 cm H2O (mean 5). Amplitude was 30–60 (median 50). After 2 h, PCO2 (mean 45 torr) was significantly lower than initial PCO2 (mean 50 torr) (p = 0.01), and pH had increased significantly (7.40 vs. 7.37, p = 0.04).

Conclusions: Nasal HFV is effective in decreasing pCO2 in stable premature infants requiring nasal CPAP support. Long‐term use of nasal HFV requires further study.
Sexual Dysfunction after Premenopausal Stage I and II Breast Cancer: Do Androgens Play a Role?
Authors: Alder Judith , Zanetti Rosanna , Wight Edward , Urech Corinne , Fink Nadine , Bitzer Johannes
Published: June 2008

Introduction

Sexual dysfunction after breast cancer has been attributed to a variety of treatment associated and psychological factors. Data on the role of a treatment-induced decrease of testosterone for the development of sexual problems in breast cancer survivors have remained inconclusive. However, androgen metabolites constitute a more reliable measure for total androgen activity.

Aim

To measure levels of total androgen activity in breast cancer patients and to investigate relevant predictors of sexual dysfunction after breast cancer.

Methods

Twenty-nine patients with a premenopausal diagnosis of Stage I or II breast cancer and terminated adjuvant treatment, completed questionnaires on sexuality, quality of relationship, body image, and depression. In addition, blood samples were taken for the analysis of sex steroids.

Main outcome measures

Female Sexual Function Index (FSFI), Relationship (PFB), Beck Depression Inventory, and European Organization for Research and Treatment of Cancer quality of life questionnaire. Analysis of dihydroepiandrosterone, dihydroepiandrosterone-sulfate, androstenedione, 17β-diol, testosterone, dihydrotestosterone, androsterone, and ADT-G, 3-alpha-diol-3G, 3-alpha-diol-17G.

Results

Low levels of sex steroids reflected the medication-induced postmenopausal status independent of the type of chemotherapy treatment. Sexual dysfunction was present in 68% of the study group. Women with a history of chemotherapy were more affected in all of the FSFI-domains. The only predictor for desire was quality of relationship, while chemotherapy was predictive for problems with arousal, lubrication, orgasm, and sexual pain. Sexual satisfaction and higher FSFI sum scores were predicted by better quality of relationship and no history of chemotherapy, together explaining 54.2% and 49.7% of the variance.

Conclusion

Sexual dysfunction after breast cancer is common and women should be informed properly at an early stage of treatment. Specific interventions have to be offered considering person-related preexisting factors and couples at risk should be supported in the transition to sexual life after breast cancer.
Long‐term evaluation of body mass at weaning and postweaning survival rates of Weddell seals in Erebus Bay, Antarctica
Authors: Proffitt Kelly M. , Garrott Robert A. , Rotella Jay J.
Published: June 2008

Abstract

Variability in juvenile survival rate is expected to be an important component of the dynamics of long‐lived animal populations. Across a range of species, individual variation in juvenile body mass has been shown to be an important cause of variation in fates of juveniles. Our goal in this paper was to estimate age‐specific apparent survival rates for Weddell seals (Leptonychotes weddellii) in Erebus Bay, Antarctica, and to investigate hypotheses about relationships between body mass at weaning and apparent survival rate for juveniles. Mark–resighting models found average apparent juvenile survival rate (survival from weaning to age 3) was similar between males and females, and revealed positive relationships between body mass at weaning and apparent juvenile survival rate. The effects of body mass on juvenile survival rate differed between the sexes and the relationship between body mass and survival rate was stronger in males. These results indicate that the magnitude of energy transferred from mother to pup during lactation likely has important consequences on offspring survival rate and maternal fitness.
Injection of sodium hyaluronate compared with a corticosteroid in the treatment of patients with temporomandibular joint osteoarthritis: clinical effects and computed tomography evaluation of osseous changes
Authors: Møystad A. , Bjørnland T. , Mork‐Knutsen B.B. , Gjærum A.A.
Published: June 2008

Aim:  We compared the osseous changes in the temporomandibular joint (TMJ), assessed on computed tomography (CT) examinations, before and after two intra‐articular TMJ injections of sodium hyaluronate or corticosteroid, in patients with osteoarthritis of the TMJ and related these to the clinical findings of pain, function and complications.

Material and methods:  Forty patients were randomly allocated into two groups for two intra‐articular injections with the two drugs. The effect of treatment was evaluated before and 6 months after the injections. Bilateral TMJ examinations with high resolution CT were obtained in 36 patients before and 6 months after treatment. Treated and contralateral TMJs were evaluated for the presence of osteoarthritic osseous abnormalities by two reviewers independently.

Results:  Injection with sodium hyaluronate was significantly more effective in decreasing pain intensity than corticosteroid. Progression, regression and no change of osseous abnormalities were demonstrated in 14, 10 and 12 TMJs, respectively, 6 months after treatment. Decreased pain intensity and increased vertical mandibular opening were observed in the majority of patients where progression of osseous changes was observed on CT.

Conclusions:  Injections in the TMJ with sodium hyaluronate or corticosteroid may reduce pain and improve function in patients with osteoarthritis. Progression, regression and no changes were observed in treated as well as untreated TMJs. Radiological evaluation of progression of osteoarthritis does not always reflect the clinical signs and symptoms.
Amputation of lower left lip following dental local anaesthetic
Authors: Akram A. , Kerr R.M.F. , Mclennan A.S.
Published: June 2008

A case is presented of an accidental bite injury of the lower lip after the administration of an inferior alveolar block. The aim is to highlight this potentially serious consequence of local anaesthetic treatment. The importance of appropriate and thorough postoperative instructions following a dental procedure under local anaesthetic is discussed.
Impacts of Demographics on Citizen’s Access to Information: An Empirical Study of District Dera Ismail Khan, North Western Frontier Province, Pakistan
Authors: Khan Najeebullah , Shah Bahadar , Nawaz Allah
Published: June 2008

The impact of demographic dimensions on local government behavior is well identified, analyzed and documented at the global level. Likewise, several studies are available on developing countries, but empirical evidence on the conditions of Pakistan is lacking. This study is an effort to unearth empirical evidence on access to information in the local government system exemplifying data from the district Dera Ismail Khan (DIK), North Western Frontier Province (NWFP). Most global hypotheses for developing countries are accepted in this study but the statistics on local data are far more different in terms of the value and weight of variables, relationships and impacts on the research concepts. The most dominant concept in the impact of access to information on the local government system is “education for all.” Mass education is a leading concept in making or breaking the role of people participation in the success or failure of local democracies. Data show that illiteracy is causing many problems, including the mass population’s unawareness of their interests and duties at the public level, thereby giving the ruling elite a free hand in exploiting public resources for self‐interest, at the cost of the public good.
Developmentalism in Korea: A Useful Tool for Explaining the Role of Social Security in the Reduction of Poverty and Inequality
Authors: Kim Sang Kyun , Kim Soo‐Wan
Published: June 2008

It is conventional wisdom that universalism is more effective than selectivism in addressing the problems of poverty and inequality. In providing income security for the elderly, retirement pensions calculated on the principle of social insurance represent universalism and social assistance benefits on the basis of means‐test selectivism. Korea has both a contributory pension scheme and social assistance program for the elderly. The social assistance began in 1961. The contributory scheme, the National Pension, started belatedly in 1988 and its coverage expanded to the entire population in 1999. We can, therefore, expect that the social security system, especially the universal pension scheme based on social insurance, has some positive impacts on the reduction of poverty and inequality. This paper, however, raises doubt as to the conventional wisdom and thus reviews the developmental process of the Korean social security system for the aged. It was found that the dominant ideological controversy revolved, not around universalism versus selectivism, but around the option between developmentalism and other strategies. Our empirical analysis showed that the public pension had little impact on the reduction of poverty and inequality, particularly in comparison with advanced welfare states. This is not surprising at all, since poverty eradication and redistribution were not major objectives of the Korean social security system. The controversy between universalism and selectivism was relatively unfamiliar in the policy process of the Korean social security system. Even though the redistributive effect is getting larger as the National Pension system becomes mature, the developmentalist model has been proved to be a more useful tool for explaining the limited role of Korean social security.
Measuring the refractive properties of the diabetic eye during blurred vision and hyperglycaemia using aberrometry and Scheimpflug imaging
Authors: Wiemer Nanouk G. M. , Dubbelman Michiel , Ringens Peter J. , Polak Bettine C. P.
Published: June 2008

Purpose: This study aimed to measure the refraction and geometry in the diabetic eye during the presence and absence of hyperglycaemia and blurred vision, using aberrometry and Scheimpflug imaging.

Methods: Aberrometry and Scheimpflug imaging were used to examine ocular refraction and higher‐order aberrations, as well as the shape of the cornea and the lens, in 25 patients with diabetes mellitus. From these parameters, the equivalent refractive index of the lens was calculated. Using pairedt‐tests, comparisons were made between a first series of measurements (Visit 1) taken in the presence of blurred vision and hyperglycaemia (> 10.0 μmol/l), and a second series of measurements (Visit 2) taken under normal conditions.

Results: The mean difference in blood glucose between Visits 1 and 2 was 5.9 mmol/l (standard deviation [SD] 3.1) (p < 0.0001). Both small hyperopic and myopic shifts of equivalent refractive error (ERE) were found in nine patients (mean absolute difference ERE: 0.38 D [SD 0.12]; p = 0.02). Furthermore, higher‐order aberrations (root mean square [RMS] error) were slightly increased in four patients (mean difference RMS error: 0.07 μm [SD 0.02]; p = 0.04) at Visit 1, compared to Visit 2. No significant changes were observed in the shape of the cornea or lens in any of the patients. No significant correlations were found between changes in blood glucose levels and the measured parameters in diabetic eyes.

Conclusions: The present study suggests that subjective symptoms of blurred vision during hyperglycaemia are not necessarily caused by changes in the refractive properties of the diabetic eye.
Determination of uric acid concentrations in human tear fluid, aqueous humour and serum
Authors: Horwath‐Winter Jutta , Kirchengast Sieglinde , Meinitzer Andreas , Wachswender Christine , Faschinger Christoph , Schmut Otto
Published: June 2008

Purpose:  The aim of this investigation was to assess and compare levels of uric acid in human tear fluid, aqueous humour and serum in cataract patients in order to obtain information about uric acid‐dependent antioxidative status.

Methods:  Reflex tear fluid, aqueous humour and serum were obtained from 103 cataract patients (52 women, 51 men). Uric acid was determined by a reversed phase chromatographic method with electrochemical detection. The Randox test was used to measure the contribution of uric acid to the total antioxidative status (TAS) of these body fluids.

Results:  Mean concentrations of uric acid were 20 ± 8 μg/ml in tear fluid, 18 ± 6 μg/ml in aqueous humour and 58 ± 15 μg/ml in serum. Significantly less uric acid was found in tear fluid (p < 0.01) and aqueous humour (p < 0.01) in female cataract patients compared with male cataract patients. There was a significant positive correlation between uric acid content in tear fluid, aqueous humour and serum, respectively (p < 0.01). The contribution of uric acid to TAS (Randox test) amounted to 38% in tear fluid, 10% in aqueous humour and 37% in serum.

Conclusions:  Uric acid was found in comparable amounts in tear fluid and aqueous humour, but these were two‐ to threefold lower than in serum. Female cataract patients had lower uric acid values in tear fluid and aqueous humour compared with male cataract patients. Uric acid is an important antioxidant, as proven by its contribution to TAS as determined by the Randox test. The precise role of uric acid in the antioxidative reactions in tear fluid and aqueous humour is still under debate.
Internal Gear Strains and Load Sharing in Planetary Transmissions: Model and Experiments
Authors: Singh Avinash , Kahraman Ahmet , Ligata Haris
Published: June 2008

This paper presents results of a comprehensive experimental and theoretical study to determine the influence of certain key factors in planetary transmissions on gear stresses and planetary load sharing. A series of tests are conducted on a family of planetary gear sets, and strains are recorded at various locations on the outer diameter and gear tooth fillet of the ring gear. Pinion position errors are introduced as a representative key manufacturing tolerance, and the resultant changes in the planetary behavior are observed. The experimental data are compared to the predictions of a state-of-the-art multibody contact analysis model—Gear System Analysis Modules (GSAM). This model is capable of including the influences of a number of system-level variables and quantifying their impact on gear strains. The model predictions are shown to compare well with the measured strain at the ring gear outer diameter and tooth fillet. GSAM predictions of planet load sharing are then used to quantify the influence of tangential pinhole position errors on three-, four-, five-, and six-planet test gear sets. These predictions also agree well with the planet load sharing experiments presented in a companion paper.
Higher-Order Tooth Flank Form Error Correction for Face-Milled Spiral Bevel and Hypoid Gears
Authors: Fan Qi , DaFoe Ronald S. , Swanger John W.
Published: June 2008

The increasing demand for low noise and high strength leads to higher quality requirements in manufacturing spiral bevel and hypoid gears. Due to heat treatment distortions, machine tolerances, variation of cutting forces, and other unpredictable factors, the real tooth flank form geometry may deviate from the theoretical or master target geometry. This will cause unfavorable displacement of tooth contact and increased transmission errors, resulting in noisy operation and premature failure due to edge contact and highly concentrated stresses. In the hypoid gear development process, a corrective machine setting technique is usually employed to modify the machine settings, compensating for the tooth flank form errors. Existing published works described the corrective machine setting technique based on the use of mechanical hypoid gear generators, and the second-order approximation of error surfaces. Today, computer numerically controlled (CNC) hypoid gear generators have been widely employed by the gear industry. The universal motion concept has been implemented on most CNC hypoid generators, providing additional freedoms for the corrections of tooth flank form errors. Higher-order components of the error surfaces may be corrected by using the higher-order universal motions. This paper describes a new method of tooth flank form error correction utilizing the universal motions for spiral bevel and hypoid gears produced by the face-milling process. The sensitivity of the changes of tooth flank form geometry to the changes of universal motion coefficients is investigated. The corrective universal motion coefficients are determined through an optimization process with the target of minimization of the tooth flank form errors. A numerical example of a face-mill completing process is presented. The developed new approach has been implemented with computer software. The new approach can also be applied to the face-hobbing process.
Atomistic Visualization of Anisotropic Wave Propagation in Crystals
Authors: Zuckerman Neil , Lukes Jennifer R.
Published: June 2008

Presented here is a new molecular dynamics simulation approach for visualizing multidimensional acoustic wave-packet propagation in anisotropic materials. This approach allows examination of longitudinal wave propagation in a selected frequency range and may also be extended to track transverse motions. The obtained results agree with analytical predictions and experimental measurements of quasilongitudinal wave front propagation in the literature. Additionally, spectral analysis reveals minor levels of frequency redistribution as the wave packet propagates, which is indicative of phonon-phonon scattering. The present approach provides new capabilities for phonon-focusing studies and offers an alternative to existing experimental and Monte Carlo techniques used for these studies.
Enhancement of Thermohydraulic Performance of Turbulent Flow in Rectangular and Square Ribbed Ducts With Twisted-Tape Inserts
Authors: Mazumder Ashis K. , Saha Sujoy K.
Published: June 2008

The thermohydraulic performance of turbulent flow of air through rectangular and square ribbed ducts with twisted-tape inserts has been experimentally studied. The performance is influenced by the twisted-tape-generated swirl flow and the boundary layer separation, reattachment, and flow recirculation due to the ribs. Correlations developed for friction factor and Nusselt number satisfactorily predict the experimental data. The performance of the ribbed ducts with full-length twisted-tape inserts is found to be better than only ribbed ducts and ducts with only twisted-tape inserts. The regularly spaced twisted-tape elements in specific cases significantly perform better than their full-length counterparts. However, the short-length twisted-tape performance is worse than the full-length twisted tapes.
Calculation Method for Thermal-Hydraulic System Simulation
Authors: Chenggong Li , Zongxia Jiao
Published: June 2008

This paper presents the fundamental approaches of modeling thermal-hydraulic component briefly. A set of lumped parameter mathematical models is developed, which are based on conservation of mass and energy. Subsequently, the connection rule for basic thermal-hydraulic components and the method to automatically generate the complete thermal-hydraulic system model are put forward. The integration methods for solving the cross-coupling thermal-hydraulic equations are also discussed for a position-controlled thermal-hydraulic system. Simulation results show the interaction between pressure and temperature. The simplified representations of thermal-hydraulic differential equations are also proposed in this paper, which can reduce simulation time. The validity of the simplified representations is judged by simulation.
Phase Change Heat Transfer Enhancement Using Copper Porous Foam
Authors: Siahpush Ali , O’Brien James , Crepeau John
Published: June 2008

A detailed experimental and analytical study has been performed to evaluate how copper porous foam (CPF) enhances the heat transfer performance in a cylindrical solid/liquid phase change thermal energy storage system. The CPF used in this study had a 95% porosity and the phase change material (PCM) was 99% pure eicosane. The PCM and CPF were contained in a vertical cylinder where the temperature at its radial boundary was held constant, allowing both inward freezing and melting of the PCM. Detailed quantitative time-dependent volumetric temperature distributions and melt/freeze front motion and shape data were obtained. As the material changed phase, a thermal resistance layer built up, resulting in a reduced heat transfer rate between the surface of the container and the phase change front. In the freezing analysis, we analytically determined the effective thermal conductivity of the combined PCM/CPF system and the results compared well to the experimental values. The CPF increased the effective thermal conductivity from 0.423W∕mKto3.06W∕mK. For the melting studies, we employed a heat transfer scaling analysis to model the system and develop heat transfer correlations. The scaling analysis predictions closely matched the experimental data of the solid/liquid interface position and Nusselt number.
Inverse Heat Conduction Applied to the Measurement of Heat Fluxes on a Rotating Cylinder: Comparison Between an Analytical and a Numerical Technique
Authors: Volle Fabien , Gradeck Michel , Maillet Denis , Kouachi Arsène , Lebouché Michel
Published: June 2008

A method using either a one-dimensional analytical or a two-dimensional numerical inverse technique is developed for measurement of local heat fluxes at the surface of a hot rotating cylinder submitted to the impingement of a subcooled water jet. The direct model calculates the temperature field inside the cylinder that is submitted to a given nonuniform and time dependent heat flux on its outer surface and to a uniform surface heat source on an inner radius. In order to validate the algorithms, simulated temperature measurements inside the cylinder are processed and used by the two inverse techniques to estimate the wall heat flux. As the problem is improperly posed, regularization methods have been introduced into the analytical and numerical inverse algorithms. The numerical results obtained using the analytical technique compare well with the results obtained using the numerical algorithm, showing a good stable estimation of the available test solutions. Furthermore, real experimental data are used for the estimation, and local boiling curves are plotted and discussed.
Particle Aspect-Ratio Effects on the Thermal Conductivity of Micro- and Nanoparticle Suspensions
Authors: Cherkasova Anna S. , Shan Jerry W.
Published: June 2008

The influence of particle anisotropy on the effective thermal conductivity of a suspension is experimentally investigated. Suspensions of micron-sized, silicon-carbide particles with varying aspect-ratio distributions were prepared and measured. It is shown that the conductivity of the silicon-carbide suspensions can be quantitatively predicted by the effective medium theory of Nan et al. (1997, “Effective Thermal Conductivity of Particulate Composites With Interfacial Thermal Resistance,” J. Appl. Phys. 81(10), pp. 6692–6699), provided the volume-weighted aspect ratio of the particles is used. Recent experimental data on multiwalled-nanotube-in-oil suspensions by Yang et al. (2006, “Thermal and Rheological Properties of Carbon Nanotube-in-Oil Dispersions,” J. Appl. Phys., 99(11), 114307) are also analyzed and shown to be in at least qualitative agreement with the effective-medium-theory prediction that the thermal conductivity of suspensions is enhanced by large aspect-ratio particles.
Solar Dynamic Modules for Space Station Freedom: The Relationship Between Fine-Pointing Control and Thermal Loading of the Aperture Plate: Part I—Analysis
Authors: Quinn R. D. , Kerslake T. W.
Published: June 2008

The dynamic equations for the simulation of Space Station Freedom configured with solar dynamic (SD) power modules are developed. The formulation permits the structure to be subjected to shuttle docking disturbances while being controlled with a “natural” vibration and tracking control approach. Multiple control cases can be performed for the purpose of investigating the relationship between actuator effort, SD pointing, and thermal loading on the receiver aperture plate. Transient, one-dimensional heat transfer equations are formulated to conservatively predict temperatures of the multilayered receiver aperture plate assembly and thermal stresses in its shield layer. Numerical results from these analyses are presented in a companion paper (Part II).
Study of Solar-Assisted Thermoelectric Technology for Automobile Air Conditioning
Authors: Mei V. C. , Chen F. C. , Mathiprakasam B. , Heenan P.
Published: June 2008

An analytical study was conducted to determine the feasibility of employing solar energy assisted thermoelectric (TE) cooling technology in automobile air conditioners. The study addressed two key issues—power requirements and availability of thermoelectric materials. In this paper, a mathematical model was developed to predict the performance of TE air conditioners and to analyze power consumption. Results show that the power required to deliver a cooling capacity of 4 kW (13,680 Btu/h) in a 38°C (100°F) environment will be 9.5 kW electric. Current TE modules suitable for air conditioning are made of bismuth telluride. The element tellurium is expected to be in short supply if TE cooling is widely implemented for auto air conditioning; some options available in this regard were studied and presented in this paper. The photovoltaic (PV) cells, assumed to cover the roof area of a compact car, can only generate about 225 W. However, this is more than enough to power a fan to provide air ventilation to the car interior, which significantly reduces the peak cooling load when the car is parked in bright sunlight.
A Nondimensional Analysis of Vertical Configuration, Ground-Coupled Heat Pump Startup
Authors: Dobson M. K. , O’Neal D. L. , Wolfe M. L.
Published: June 2008

A nominal 10.6 kW (three ton), vertical configuration, ground-coupled heat pump was installed in Abilene, TX in Dec. 1989 and has been monitored since then using a remote data acquisition system. Monitored data include: temperature and relative humidity of return and supply air, water temperature entering and leaving the condenser, power consumption of the individual system components, cycling rate, on-time, and soil temperatures at various depths and radial locations. Water and air flow rates have been measured twice during the monitored period, and have remained constant. The measured quantities allow calculation of instantaneous capacity, power, coefficient of performance (COP), and ground-coil heat rejection. Data for operation in the cooling mode are discussed herein. Based on the experimental data, it was discovered that the water temperature entering the condenser (EWT) exhibited a prolonged minimum after startup due to cooling of the water during the off-cycle. The decreased levels of EWT early in the cycle increased capacity and decreased power, both acting to increase the COP. Two sets of nondimensional groups were developed based on the experimental data. The first nondimensional group allowed analysis of startup independent of changes in independent variables, while the second nondimensional group quantified the performance benefits due to cyclic operation. The results tended to indicate that an improvement in COP may be achieved in cyclic operation, due to the decreased values of EWT early in the cycle. This is in contrast to behavior for air source heat pumps, where cycling always degrades efficiency.
Investigation of a Direct Catalytic Absorption Reactor for Hazardous Waste Destruction
Authors: Skocypec R. D. , Hogan R. E.
Published: June 2008

Direct Catalytic Absorption Reactors (DCARs) use a porous solid matrix to volumetrically absorb solar energy. This energy is used to promote heterogeneous chemistry on the catalytic surface of the absorber with fluid-phase reactant species. Experimental efforts at Sandia National Laboratories (SNL) are using a DCAR to destroy hazardous chemical waste. A numerical model, previously developed to analyze solar volumetric air-heating receivers and methane-reforming reactors, is extended in this work to include the destruction of a chlorinated hydrocarbon chemical waste, 1,1,1-trichloroethane (TCA). The model includes solar and infrared radiation, heterogeneous chemistry, conduction in the solid absorber, and convection between the fluid and solid absorber. The predicted thermal and chemical conditions for typical operating conditions at the SNL solar furnace suggest that TCA can be destroyed in a DCAR. The temperature predictions agree well with currently available thermocouple data for heating carbon dioxide gas in the DCAR. Feasibility and scoping calculations show trichloroethane destruction efficiencies up to 99.9997 percent at a trichloroethane flow rate of 1.7 kg/hr may be obtainable with typical SNL solar furnace fluxes. Greater destruction efficiencies and greater destruction rates should be possible with higher solar fluxes. Improvements in reactor performance can be achieved by tailoring the absorber to alter the radial mass flux distribution in the absorber with the radial solar flux distribution.
CuInSe2 Thin Film Modules for Utility Applications
Authors: Fredric C. , Tarrant D. , Jensen C. , Hummel J. , Ermer J.
Published: June 2008

Recent advances in the efficiency and manufacturing technology of CuInSe2 (CIS) thin films demonstrate the opportunity for low-cost large-scale production of photovoltaics for utility applications. Large area (0.4 m2) submodules with 9.7 percent aperture efficiencies yielding 37.8 watts have been fabricated. Thin film fabrication techniques used in the production of modules enable reduced production costs compared with those for single crystal silicon. The performance of 0.4 m2 modules is projected to exceed 50 watts, based on performance achieved to date on 0.1 m2 modules and small area test devices. Preliminary tests packaged (encapsulated and framed) modules show no significant losses after 15 1/2 months of continuous outdoor exposure. Fabrication of 0.4 m2 modules to demonstrate the feasibility of large-scale commercialization of CIS thin film photovoltaics for utility applications is currently under way.
Design and Construction of a Solar-Electric Vehicle
Authors: Bhavnani S. H.
Published: June 2008

Recent concerns relating to global warming caused by greenhouse gases, coupled with a growing awareness of the limited available resources of fossil fuels, have spurred an interest in alternative energy powered vehicles. This paper describes the analysis, development, and testing of an aerodynamic vehicle powered by photovoltaic cells. The primary components of the vehicle are the composite material body, the aluminum space frame, the wheel hubs and front suspension assembly, the drive train, and the electrical system. The frame was designed using finite element analysis with the components of the frame modeled as beam elements. The body, designed to have a very high strength-to-weight ratio, was of graphite/Kevlar/Nomex sandwich construction. Testing was carried out using the three-point bend test to determine the optimal sandwich cross-sectional configuration. The design of the front suspension, the wheel hubs, and the power transmission are also discussed. The electrical system, based on a monocrystalline photovoltaic cell assembly, and silver-zinc storage cells, is also described. Finally, results of the optimization routine developed are also described.
Effect of Air Flow on Heat Transfer in Walls
Authors: Krarti M.
Published: June 2008

An analytical model to characterize the air leakage effects on the heat transfer within a permeable one-layered wall is presented. The general solution to the steady-periodic problem is presented. Temperature profiles and heat flux variations within the wall are analyzed. The effect of air flows on heat transmission through the wall are discussed using a parametric analysis. The thermal advantages of intentionally circulating air through building walls—to provide ventilation—are analyzed and discussed. In particular, the thermal performance of dynamic walls integrated in a whole building is analyzed as a function of the infiltration rate and the building thermal load. It is found that the dynamic walls can achieve energy savings of up to 20 percent of total building thermal load.
Correlation Between Ultraviolet Radiation and Global Radiation in Riyadh, Saudi Arabia
Authors: Mujahid A. M.
Published: June 2008

The global ultraviolet and global radiation were measured and recorded on an hourly basis in Riyadh, Saudi Arabia (lat. 24.6°N, long. 46.7°) during the period 1984–1989. Global radiation, G, was measured by an Eppley PSP pyranometer (0.285≤λ≤2.8 μm) and an Eppley TUVR radiometer (0.29≤λ≤0.385 μm) was used for the measurement of the ultraviolet radiation, UV. Both instruments were mounted on a horizontal surface. The results showed that the monthly average daily ultraviolet radiation was 197.6 Whm−2. The ratio of the monthly average daily ultraviolet radiation to the monthly average daily global radiation (Ku) varied between 0.031 to 0.037, with a mean value of 0.034. Comparison with results obtained in Kuwait, Dhahran, and Makkah showed that the data of Riyadh are in good agreement with those of Makkah and Dhahran; however, it underestimates Kuwait data. A regression correlation between Ku and KT (the ratio of the monthly average daily values of global radiation to extraterrestrial radiation) is developed. Another regression correlation between ultraviolet and global radiation on an hourly basis is also developed.
Fabric Stratification Manifolds for Solar Water Heating
Authors: Davidson J. H. , Adams D. A.
Published: June 2008

The level of thermal stratification that can be maintained in forced-flow, direct solar water-heating systems using a fabric manifold is studied in a 372-liter tank with an inlet flow rate of 0.07 1/s. A rib-knit, lightweight, spun-orlon acrylic is the most effective manifold material in a comparative study of 13 synthetic and natural fabrics. Thermal stratification (or more appropriately mixing) in the tank equipped with this acrylic manifold is compared to the level of stratification achieved using a rigid, porous manifold and a conventional drop-tube inlet. Initial tank temperature profile, temperature of the water entering the tank, and test duration are varied in three testing schemes. Comparison of vertical temperature profiles and height-weighted energy stored in the tank indicate that under realistic operating conditions, the fabric manifold is 4 percent more effective than the rigid manifold, and 48 percent more effective than the conventional drop-tube inlet.