bluuebunny/crossref_metadata_2025 huggingface dataset:
Ways of Reading Animals in Victorian Literature, Culture and Science
Authors: Mayer Jed
Published: May 2010

By decentring the human perspective and shifting focus towards the diverse roles of animals in human culture, the burgeoning field of animal studies is transforming the way we read texts past and present. Since Harriet Ritvo’s groundbreaking work,The Animal Estate: The English and Other Creatures in the Victorian Era(1987), the history of animals has been of particular interest to scholars of Victorian literature and culture. Similarly, those interested in the history of animals have frequently turned their attention to this period, which witnessed the emergence of public zoos, animal protection societies and the theory of natural selection. Of particular interest to scholars in a variety of fields have been the vivisection debates of the later‐19th century. Beginning in the 1870s, animal experimentation came to be more widely practiced in British physiological laboratories, bringing into conflict scientific and humanitarian interests in the animal, as antivivisectionists and advocates of animal research debated their right to speak for the nonhuman animal. Although the moral status of the experimental animal was at the centre of these debates, the animal presence has been notably absent from accounts of the period by historians of science. A concern with the ethical problems raised by the human use of animals is also absent or muted in recent scholarship on cultural representations of animals in the Victorian period. This essay considers these animal absences and suggests areas for further inquiry and development, arguing that the subject of the vivisection debates of the later‐19th century could serve as a meeting point for scholars interested in science studies, Victorian literature and culture, and the burgeoning field of animal studies.
Complex Methylmercury–Cysteine Alters Mercury Accumulation in Different Tissues of Mice
Authors: Roos Daniel Henrique , Puntel Robson Luiz , Lugokenski Thiago Henrique , Ineu Rafael Porto , Bohrer Denise , Burger Marilise E. , Franco Jeferson L. , Farina Marcelo , Aschner Michael , Rocha João Batista T. , De Vargas Barbosa Nilda B.
Published: May 2010

Abstract:  Methylmercury (MeHg) can cause deleterious effects in vertebrate tissues, particularly in the central nervous system. MeHg interacts with sulfhydryl groups from low and high molecular weight thiols in the blood, which can facilitate MeHg uptake into different tissues. The purpose of this study was to examine the effect of MeHg–Cysteine (MeHg‐Cys) complex administration on Hg‐uptake in cerebral areas (cortex and cerebellum), liver and kidney of adult mice. Animals were divided into four groups: control (1 mL/kg distilled water), MeHg (2 mg/kg), Cys (2 mg/kg) and MeHg–Cys complex (0.8 molar ratio). Mice received one intraperitoneal injection per day for 60 consecutive days. Treatment with MeHg significantly increased mercury concentrations in all tissues analysed when compared with the control group. The accumulation of mercury in brain and in liver was further increased in animals that received MeHg–Cys complex when compared with the MeHg alone group. However, renal Hg decreased in MeHg‐Cys treated mice, when compared with the group treated only with MeHg. In summary, the transport of MeHg–Cys complex was tissue‐specific, and we observed an increase in its uptake by liver and brain as well as a decrease in kidney.
Dietary Factors, Mediterranean Diet and Erectile Dysfunction
Authors: Esposito Katherine , Giugliano Francesco , Maiorino Maria Ida , Giugliano Dario
Published: May 2010

Introduction

Although epidemiological evidence seems to support a role for lifestyle factors in the pathogenesis of erectile dysfunction (ED), limited data are available suggesting that dietary changes may improve ED.

Aim

To provide an update on clinical evidence regarding the role of dietary factors in ED.

Methods

A systematic literature search was performed using MEDLINE and other database (EMBASE, SCOPUS) with MeSH terms and keywords for “erectile dysfunction”, “diet”, “dietary patterns”, “Mediterranean diet”, and “lifestyle”.

Main Outcome Measures

To examine the data relating to erectile dysfunction with dietary factors, its relationship and the impact of dietary treatment.

Results

Only few studies assessed the role or the effect of diet on ED. A dietary pattern which is high in fruit, vegetables, nuts, whole grains, and fish but low in red and processed meat and refined grains is more represented in subjects without ED. Mediterranean diet has been proposed as a healthy dietary pattern based on evidence that greater adherence to this diet is associated with lower all-cause and disease-specific survival. In type 2 diabetic men, those with the highest adherence to the Mediterranean diet had the lowest prevalence of ED and were more likely to be sexually active. In clinical trials, Mediterranean diet was more effective than a control diet in ameliorating ED or restoring absent ED in people with obesity or metabolic syndrome.

Conclusion

The adoption of a Mediterranean diet may be associated with an improvement of erectile dysfunction.
Chronic Administration of Sildenafil Modified the Impaired VEGF System and Improved the Erectile Function in Rats with Diabetic Erectile Dysfunction
Authors: Liu Guihua , Sun Xiangzhou , Dai Yuping , Zheng Fufu , Wang Daohu , Huang Yanping , Bian Jun , Deng Chunhua
Published: May 2010

Introduction

Men frequently develop diabetic erectile dysfunction (DMED), as a result of endothelial dysfunction. DMED patients often have reduced efficacy with phosphodiesterase type 5 inhibitors therapy.

Aim

To determine whether chronic sildenafil administration can modify the impaired vascular endothelial growth factor (VEGF) system and improve the erectile function in rats with diabetic erectile dysfunction.

Methods

A group of Sprague Dawley rats (n=30) with DMED were induced by intraperitoneal injection of streptozotocin (40 mg/kg) and screened by subcutaneous injection of Apomorphine (100 mg/kg). They were then exposed to either vehicle or sildenafil (prescribed in our hospital, 5 mg/kg and 10 mg/kg, respectively) for 10 weeks. An additional nondiabetic and age-matched control group (n=10) was also allocated and given the routine diet for the same period. Assessments were performed to both groups at 36 hours after the last dose of sildenafil. Penile intracavernous pressure (ICP), mean arterial pressure (MAP), penile tissue morphology, immunohistologic analysis, and Western blot analysis of VEGF, VEGFR1, and eNOS were determined.

Main Outcome Measure

Functional, morphological, and proteomical changes on penile structures by the chronic Sildenafil (5 mg/kg and 10 mg/kg, respectively) administration were determined.

Results

A significant increase of ICP, ICP/MAP ratio, and area under the curve were observed in the both groups treated by sildenafil (5 mg/kg and 10 mg/kg, respectively), compared with the DMED rats without receiving Sildenafil. Immunohistochemical staining of their penile tissue showed a decrease in VEGF, VEGFR1, and eNOS staining in the controlled group compared with an improvement in the chronic sildenafil administration group. Western blot analysis demonstrated exactly the same results.

Conclusion

We demonstrated that daily sildenafil administration can restore the impaired VEGF system in the penis of DMED rats and progressively improve both erectile function and endothelial function, suggesting a potential general mechanism of improved signaling through the VEGF/eNOS signaling cascade.
Artificial Neural Networks and the Study of the Psychoactivity of Cannabinoid Compounds
Authors: Honório Káthia M. , De Lima Emmanuela F. , Quiles Marcos G. , Romero Roseli A. F. , Molfetta Fábio A. , Da Silva Albérico B. F.
Published: May 2010

Cannabinoid compounds have widely been employed because of its medicinal and psychotropic properties. These compounds are isolated fromCannabis sativa(or marijuana) and are used in several medical treatments, such as glaucoma, nausea associated to chemotherapy, pain and many other situations. More recently, its use as appetite stimulant has been indicated in patients with cachexia or AIDS. In this work, the influence of several molecular descriptors on the psychoactivity of 50 cannabinoid compounds is analyzed aiming one obtain a model able to predict the psychoactivity of new cannabinoids. For this purpose, initially, the selection of descriptors was carried out using the Fisher’s weight, the correlation matrix among the calculated variables and principal component analysis. From these analyses, the following descriptors have been considered more relevant: ELUMO(energy of the lowest unoccupied molecular orbital), Log P (logarithm of the partition coefficient), VC4 (volume of the substituent at the C4 position) and LP1 (Lovasz–Pelikan index, a molecular branching index). To follow, two neural network models were used to construct a more adequate model for classifying new cannabinoid compounds. The first model employed was multi‐layer perceptrons, with algorithm back‐propagation, and the second model used was the Kohonen network. The results obtained from both networks were compared and showed that both techniques presented a high percentage of correctness to discriminate psychoactive and psychoinactive compounds. However, the Kohonen network was superior to multi‐layer perceptrons.
Linkage of Large-Vessel Carotid Atherosclerotic Stroke to Inflammatory Genes via a Systematic Screen
Authors: Belter Inna , Wu Tianxia , Hipp Heather , Walter Joan , Scully Michele , Nyquist Paul A. , Bollettino Antonella , Goldman David , Max Mitchell B. , DeGraba Thomas J.
Published: May 2010

Background

Inflammatory cytokines including the IL-1 family, TNF-α and IL-6 mediate the formation of thrombosis on the luminal surface of atherosclerotic plaques. Gene polymorphisms that regulate these cytokines' expression may explain part of the variation in susceptibility to stroke in patients with carotid atherosclerosis. The aim of this study was to evaluate the role of single-nucleotide polymorphisms (SNPs) and haplotypes in inflammatory genes as they relate to symptomatic carotid atherosclerosis.

Methods

The study included 95 subjects with symptomatic (transient ischaemic attacks or stroke) and 113 subjects with asymptomatic carotid atherosclerotic disease. A panel of evenly spaced SNPs including previously reported functionally significant polymorphisms were genotyped for IL-1β (10 SNPs), IL-1α (nine SNPs), IL-1RN (11 SNPs), IL-6 (seven SNPs) and TNF-α and TNF-β (seven SNPs).

Results

Using single SNP analysis, IL-1RN rs315934 ( P = 0·025), IL-1RN rs315946 ( P = 0·042), IL-1RN rs315921 ( P = 0·035), IL-6 rs1180243 ( P = 0·018) and IL-1α rs2071373 ( P = 0·025) were associated with decreased odds of symptomatic carotid disease. Additionally, two diplotypes of the IL-1 RN gene ( P = 0·023 and 0·0064) and one diplotype in the IL-1α gene ( P = 0·02) were associated with a protective affect from cerebral ischaemic events. Logistic analysis for interaction of the protective SNPs reveals an additive effect of all SNP pair combinations.

Conclusion

These results suggest that genetic polymorphisms in proinflammatory genes may contribute to interindi-vidual differences in the development of symptomatic carotid atherosclerotic disease.
Stroke Education: Discrepancies among Factors Influencing Prehospital Delay and Stroke Knowledge
Authors: TeuschI Yvonne , Brainin Michael
Published: May 2010

Background

Time is essential for the treatment of acute stroke. Much time is lost outside the hospital, either due to failure in identifying stroke symptoms or due to a delay in notification or transport. We review studies reporting factors associated with better stroke knowledge and shorter time delays. We summarise the evidences for the effect of stroke knowledge and education on people's reaction in the acute situation of stroke.

Methods

We searched MEDLINE for studies reporting factors associated with prehospital time of stroke patients, or knowledge of stroke symptoms. Further, we searched for studies reporting educational interventions aimed at increasing stroke symptom knowledge in the population.

Findings

We included a total of 182 studies. Surprisingly, those factors associated with better stroke knowledge such as education and sociodemographic variables were not related to shorter time delays. Few studies report shorter time delays or better stroke knowledge in persons having suffered a previous stroke. Factors associated with shorter time delays were more severe stroke and symptoms regarded as serious, but not better knowledge about the most frequent symptoms such as hemiparesis or disorders of speech. Only 25–56% of patients recognised their own symptoms as stroke. While stroke education increases the knowledge of warning signs, a few population studies measured the impact of education on time delays; in such studies, time delays decreased after education. This may partly be mediated by better organisation of EMS and hospitals.

Interpretation

There is a discrepancy between theoretical stroke knowledge and the reaction in an acute situation. Help-seeking behaviour is more dependent on the perceived severity of symptoms than on symptom knowledge. Bystanders play an important role in the decision to call for help and should be included in stroke education. Education is effective and should be culturally adapted and presented in a social context. It is unclear which educational concept is best suited to enhance symptom recognition in the acute situation of stroke, especially in view of discrepancies between knowledge and action.
RMB Internationalization and Its Implications for Financial and Monetary Cooperation in East Asia
Authors: Park Yung Chul
Published: May 2010

This paper emphasizes the importance of the denomination of financial assets rather than trade invoicing as a long‐term determinant of an international currency. China needs to liberalize and open its financial system and make the RMB fully convertible, and to adopt a more flexible exchange rate system to speed up its currency internationalization, for which China could follow either a global or regional approach. The global approach is a riskier and more unpredictable strategy because it would demand a scope and timeframe of financial liberalization that is likely to be beyond China's institutional capacity over the coming decade. There are two options that could be taken in following the regional approach. One is creating an ASEAN+New 3 (the Chinese Mainland, Hong Kong, and Taiwan) RMB bloc and the other is liberalizing China's financial industries and internationalizing the RMB by playing a leading role in East Asia's economic integration within the framework of ASEAN+3. This paper concludes that the latter is a more realistic and effective approach for China.
Economic Openness and Subjective Well‐being in China
Authors: Xin Wen , Smyth Russell
Published: May 2010

Using a large household survey administered across 30 cities in September 2003, we examine the relationship between the degree of economic openness, measured as the sum of imports and exports as a share of GDP, and subjective well‐being in urban China. We find that respondents who live in cities with high levels of economic openness report significantly lower levels of subjective well‐being ceteris paribus. We offer four explanations for this result; namely, inadequate social protection in the face of globalization, unfulfilled expectations, political dissatisfaction and anomie.
Anomaly in China's Dollar–RMB Forward Market
Authors: Wang Yi David
Published: May 2010

Newly‐established data on onshore deliverable US dollar–RMB forwards and the Shanghai Interbank Offered Rate from October 2006 to April 2009 reveal significant violations of covered interest rate parity. This paper explains the cause of this anomaly. Deviations in the forward market are caused by an increase in US dollar‐to‐RMB conversion restrictions. Given that Chinese monetary authorities want to prevent market participants from taking advantage of the predictable appreciation of the RMB, China's State Administration of Foreign Exchange has to tighten up the control on US dollar‐to‐RMB conversions. Under the tightened conversion restrictions, similar deviations will resurface in the forward market whenever hot money inflow increases. One way to avoid covered interest rate parity violations in the forward market is to decrease hot money inflow into China by maintaining a stable and credible exchange rate policy.
Information Measures in Perspective
Authors: Ebrahimi Nader , Soofi Ehsan S. , Soyer Refik
Published: May 2010

Information‐theoretic methodologies are increasingly being used in various disciplines. Frequently an information measure is adapted for a problem, yet the perspective of information as the unifying notion is overlooked. We set forth this perspective through presenting information‐theoretic methodologies for a set of problems in probability and statistics. Our focal measures are Shannon entropy and Kullback–Leibler information. The background topics for these measures include notions of uncertainty and information, their axiomatic foundation, interpretations, properties, and generalizations. Topics with broad methodological applications include discrepancy between distributions, derivation of probability models, dependence between variables, and Bayesian analysis. More specific methodological topics include model selection, limiting distributions, optimal prior distribution and design of experiment, modeling duration variables, order statistics, data disclosure, and relative importance of predictors. Illustrations range from very basic to highly technical ones that draw attention to subtle points.
Silencing and re‐expression of retinoic acid receptor beta2 in human melanoma
Authors: Fan Jun , Eastham Linda , Varney Melinda E. , Hall Adam , Adkins Nicolas L. , Sollars Vincent E. , Georgel Philippe , Niles Richard M.
Published: May 2010

Many melanoma cells are resistant to the anti‐proliferative effect of all trans retinoic acid (ATRA). Retinoic Acid Receptor‐β2 (RAR‐β2) mediates the ATRA growth inhibition. We found a correlation between the anti‐proliferative activity of ATRA and expression of RAR‐β2. There was not a strict correlation between DNA methylation of RAR‐β gene and its expression. There was no difference in global and RARβ specific nucleosome repeat length (NRL) in melanoma and melanocytes or between control and ATRA treated cells. Pan‐acetylation of H3 and H4 within the RAR‐β gene promoter was higher in cells expressing RAR‐β2. All trans retinoic acid treatment of responsive cells did not change pan‐acetylation of H3/H4, but addition of ATRA to non‐responsive cells increased H4 pan‐acetylation. Phytochemicals or the histone deacetylase inhibitor Trichostatin A did not restore expression of RAR‐β2. Treatment of WM1366 melanoma cells with 5‐aza 2′‐deoxycytidine reactivated RAR‐β2 gene expression and restored the ability of ATRA to further induce the expression of this gene. Therefore, promoter methylation is responsible for silencing of RAR‐β2 in some melanoma cells and pan‐acetylation of H3 likely plays a permissive role in expression of RAR‐β2.
Early School Leaving among Immigrants in Toronto Secondary Schools
Authors: ANISEF PAUL , BROWN ROBERT S. , PHYTHIAN KELLI , SWEET ROBERT , WALTERS DAVID
Published: May 2010

Les données du Conseil scolaire du district de Toronto sont utilisées pour déterminer quelles sont les répercussions de vivre sous le seuil de faible revenu (SFR) sur le décrochage à l'école secondaire, en tenant compte du statut de la génération d'immigrants ainsi que d'une diversité de facteurs de risques (par exemple, le pays d'origine, l'âge à l'entrée de l'école secondaire, la réussite scolaire). Les résultats ont indiqué que la mesure SFR du voisinage constituait un prédicteur significatif du décrochage scolaire, indépendamment du statut d'immigrant. L'explication du taux de décrochage des immigrants à partir du facteur de la génération n'a obtenu que peu de soutien. La région d'origine s'est avérée un prédicteur marquant du décrochage où l'on constatait des différences entre les groupes d'immigrants et entre les étudiants immigrants et les étudiants originaires du pays.

While education statistics confirm that there is little difference in the dropout rates of native‐born and immigrant youth, analyses of Toronto District School Board (TDSB) data have revealed significant variation in school persistence within immigrant groups. Among newcomer youth, the decision to leave school early has been reported to be strongly influenced by socioeconomic status as well as such factors as country of origin, age at arrival, generational status, family structure, and academic performance. While living in low‐income conditions is thought to place both foreign‐ and Canadian‐born youth at risk of poor school performance and early school withdrawal, their substantially higher incidence of poverty suggests that today's immigrant youth are likely to face greater obstacles to academic success that may in turn have detrimental, long‐term consequences. This paper uses TDSB data to investigate the extent to which living below the low‐income cutoff affects the likelihood of dropping out of secondary school, while taking into account generational status as well as a variety risk factors, noted above. Policy implications are discussed.
Comparison of laparoscopic and open adrenalectomy for pheochromocytoma in a single center
Authors: Okegawa T , Nutahara K , Higashihara E
Published: May 2010

Introduction: Laparoscopic adrenalectomy is recognized as a safe and feasible surgical procedure for removing adrenal masses, though some reports have questioned its use because of an increased risk of cardiovascular complications. This study aims to compare laparoscopic surgery and open surgery for pheochromocytoma.

Methods: We analyzed 26 patients operated on for adrenal pheochromocytoma (laparoscopic surgery: 11 patients; open surgery: 15 patients) at Kyorin University Hospital from April 1995 to July 2009. Patient records were analyzed with regards to operative time, blood loss, complications, blood pressure during surgery, amount of analgesia required in patient‐controlled analgesia, time to oral intake, length of hospital stay, and other factors.

Results: Mean tumor size was greater in the open surgery patients. Blood loss was significantly less extensive in the laparoscopic surgery patients. Rates of intraoperative hypertension (defined as a sudden rise in systolic blood pressure of >200 mmHg) and hypotension (systolic blood pressure of <80 mmHg) immediately after clamping of the adrenal vein were significantly lower in the laparoscopic surgery patients. No significant differences were found between the two groups with respect to operative time, occurrence of complications, and analgesic requirements. Only one case (9.1%) required conversion from laparoscopic to open surgery because intraoperative complications, specifically uncontrollable hemorrhaging. Time to oral intake after surgery and hospital stay were significantly shorter in the laparoscopic surgery patients. During the follow‐up period, there was no mortability or recurrence of endocrinopathy in the two groups.

Conclusion: We consider the safety of laparoscopic adrenalectomy for pheochromocytoma to be similar to that of open surgery.
Reflections on Success and Retention in Urban Science Education: Voices of Five African‐American Science Teachers Who Stayed
Authors: Fraser‐Abder Pamela
Published: May 2010

This study highlights the factors that contribute to excellence in urban science teaching as pinpointed by five urban African‐American science teachers who have taught successfully in the urban system for over 10 years. These teachers shared their experiences and reflections on the qualities that contributed to their success and persistence as urban science teachers. Their ability to understand and care for their students was a major contributing factor; other contributing factors included in‐depth knowledge and love of science, caring and commitment to the whole child, effective classroom management strategies, high expectations and motivation of their students, and an understanding and acceptance of the varying parental involvement in the educational decisions about their child.
Mathematics Teachers' Instructional Practices in an Era of High‐Stakes Testing
Authors: Vogler Kenneth E. , Burton Megan
Published: May 2010

This study explored mathematics teachers' instructional practices in the context of high‐stakes testing. Data were obtained from a survey instrument given to a stratified sample of Mississippi and Tennessee teachers who teach the same content tested on their state's high school graduation examination. An analysis showed teachers using a balance of standards‐based and traditional practices and tools, including textbook‐based assignments, calculators, open‐response questions, supplementary materials, and multiple‐choice questions. Over 90% of teachers from both states felt that an “interest in helping my students attain test scores that will allow them to graduate high school” was a factor influencing their instructional practices. This was followed by an “interest in helping my school improve high school graduation examination scores,” and “belief these are the best instructional practices.”
Assessment of assemblage‐wide temporal niche segregation using null models
Authors: Castro‐Arellano Ivan , Lacher Thomas E. , Willig Michael R. , Rangel Thiago F.
Published: May 2010

1. Although time can be subdivided to promote species coexistence, quantitative examination of assemblage‐wide temporal niche overlap has seldom been explored with appropriate null models. Because of the sequential and continuous nature of time, it requires a different kind of randomization model than those used to assess subdivision of discrete and non‐sequential resources (e.g. food types and microhabitats).

2. For two common niche overlap indices (Pianka and Czekanowski), we compared the responses of two common randomization models and a newly developed model (ROSARIO) to different levels of temporal autocorrelation, specialization and coincidence of activity.

3. Although qualitatively similar results characterized overlap indices, results differed depending on randomization model. Temporal resolution of the data and amount of temporal specialization in an assemblage can have large effects on model outcomes. ROSARIO is as powerful as the models used for analyses of overlap of nominal and unordered resources, but it is more appropriate for ranked and interval data, as it maintains the empirical temporal autocorrelation within species.

4. ROSARIO can be a useful tool for exploration of assemblage‐wide patterns of overlap in the use of resources that occur as cyclical phenomena, such as diel phases, yearly seasons, lunar tides and climate oscillations.
Performance Assessment of an Annular S-Shaped Duct
Authors: Bailey D. W. , Britchford K. M. , Carrote J. F. , Stevens S. J.
Published: May 2010

An experimental investigation has been carried out to determine the aerodynamic performance of an annular S-Shaped duct representative of that used to connect the compressor spools of aircraft gas turbine engines. For inlet conditions in which boundary layers are developed along an upstream entry length, the static pressure, shear stress and velocity distributions are presented. The data show that as a result of flow curvature, significant streamwise pressure gradients exist within the duct, with this curvature also affecting the generation and suppression of turbulence. The stagnation pressure loss within the duct is also assessed and is consistent with the measured distributions of shear stress. More engine representative conditions are provided by locating a single-stage compressor at inlet to the duct. Relative to the naturally developed inlet conditions, the flow within the duct is less likely to separate, but mixing out of the compressor blade wakes increases the measured duct loss. With both types of inlet conditions, the effect of a radial strut, such as that used for carrying loads and engine services, is also described both in terms of the static pressure distribution along the strut and its contribution to overall loss.
Circumferentially Smeared Computed Effects of Rim Seal Clearance on Wheelspace Thermal Distributions
Authors: Ko S. H. , Rhode D. L. , Guo Z.
Published: May 2010

An advanced finite volume computer code, recently bench-marked against rotor—stator cavity measurements (Ko and Rhode, 1992), was used to obtain an enhanced partial understanding of hot gas ingress heating of a generic turbine wheelspace cavity. This problem is extremely complicated, with a three-dimensional, probably circumferentially periodic ingress/egress flow through the rim seal due to mainstream pressure asymmetries resulting from the presence of blades, etc. The present study does not assume that the complete problem can be modeled as steady and two-dimensional axisymmetric. Rather, the objective of this study is to obtain a partial understanding of the complete problem from investigating the circumferentially smeared, steady, two-dimensional axisymmetric sub-problem. It was found that, contrary to the case of the nominal rim seal axial clearance, for a clearance of one-fourth of the nominal value, the temperature of the “hot spot” on the rotor is sharply reduced with increasing purge-coolant flow because the rim seal gap recirculation zone does not form. Also, it was found that smaller rim seal axial clearances give less rotational drag as well as less heat transport from the mainstream into the wheelspace.
Grid Orthogonality Effects on Predicted Turbine Midspan Heat Transfer and Performance
Authors: Boyle R. J. , Ameri A. A.
Published: May 2010

The effect of five different C-type grid geometries on the predicted heat transfer and aerodynamic performance of a turbine stator is examined. Predictions were obtained using two flow analysis codes. One was a finite difference analysis, and the other was a finite volume analysis. Differences among the grids in terms of heat transfer and overall performance were small. The most significant difference among the five grids occurred in the prediction of pitchwise variation in total pressure. There was consistency between results obtained with each of the flow analysis codes when the same grid was used. A grid-generating procedure in which the viscous grid is embedded within an inviscid type grid resulted in the best overall performance.
Passage Flow Structure and Its Influence on Endwall Heat Transfer in a 90 deg Turning Duct: Mean Flow and High Resolution Endwall Heat Transfer Experiments
Authors: Wiedner B. G. , Camci C.
Published: May 2010

Three-dimensional measurements of the mean velocity field have been made in a square-cross-sectional, strongly curved, 90 deg turbulent duct flow. The mean radius to duct width ratio was 2.3. The study was performed as part of an overall investigation of the physics of endwall convective heat transfer. All three components of the velocity vector and the static and total pressure fields were measured using a five-hole probe at four duct cross sections: inlet, 0, 45, and 90 deg. Preliminary turbulence measurements using a single sensor hot wire at the inlet cross section were also obtained to provide streamwise fluctuation levels through the boundary layer. The endwall heat transfer coefficient distribution was determined using a steady-state measurement technique and liquid crystal thermography. A high-resolution heat transfer map of the endwall surface from far upstream of the curve through the 90 deg cross section is presented. The three-dimensional velocity field measurements indicate that a highly symmetric, strong secondary flow develops in the duct with a significant transfer of streamwise momentum to the transverse directions. The cross-stream vorticity components within the measurement plane were estimated using the five-hole probe data and an inviscid from of the incompressible momentum equation. The development of the total and static pressure fields, the three-dimensional mean velocity field, and all three components of the vorticity field are discussed. The endwall heat transfer distribution is interpreted with respect to the measured mean flow quantities.
The Influence of Neighboring Blade Rows on the Unsteady Aerodynamic Response of Cascades
Authors: Hall K. C. , Silkowski P. D.
Published: May 2010

In this paper, we present an analysis of the unsteady aerodynamic response of cascades due to incident gusts (the forced response problem) or blade vibration (the flutter problem) when the cascade is part of a multistage fan, compressor, or turbine. Most current unsteady aerodynamic models assume the cascade to be isolated in an infinitely long duct. This assumption, however, neglects the potentially important influence of neighboring blade rows. We present an elegant and computationally efficient method to model these neighboring blade row effects. In the present method, we model the unsteady aerodynamic response due to so-called spinning modes (pressure and vorticity waves), with each mode corresponding to a different circumferential wave number and frequency. Then, for each mode, we compute the reflection and transmission coefficients for each blade row. These coefficients can be obtained from any of the currently available unsteady linearized aerodynamic models of isolated cascades. A set of linear equations is then constructed that couples together the various spinning modes, and the linear equations are solved via LU decomposition. Numerical results are presented for both the gust response and blade vibration problems. To validate our model, we compare our results to other analytical models, and to a multistage vortex lattice model. We show that the effect of neighboring blade rows on the aerodynamic damping of vibrating cascades is significant, but nevertheless can be modeled with a small number of modes.
Numerical Analysis of Convective Heat Transfer From an Elliptic Pin Fin Heat Sink With and Without Metal Foam Insert
Authors: Seyf Hamid Reza , Layeghi Mohammad
Published: May 2010

A numerical analysis of forced convective heat transfer from an elliptical pin fin heat sink with and without metal foam inserts is conducted using three-dimensional conjugate heat transfer model. The pin fin heat sink model consists of six elliptical pin rows with 3 mm major diameter, 2 mm minor diameter, and 20 mm height. The Darcy–Brinkman–Forchheimer and classical Navier–Stokes equations, together with corresponding energy equations are used in the numerical analysis of flow field and heat transfer in the heat sink with and without metal foam inserts, respectively. A finite volume code with point implicit Gauss–Seidel solver in conjunction with algebraic multigrid method is used to solve the governing equations. The code is validated by comparing the numerical results with available experimental results for a pin fin heat sink without porous metal foam insert. Different metallic foams with various porosities and permeabilities are used in the numerical analysis. The effects of air flow Reynolds number and metal foam porosity and permeability on the overall Nusselt number, pressure drop, and the efficiency of heat sink are investigated. The results indicate that structural properties of metal foam insert can significantly influence on both flow and heat transfer in a pin fin heat sink. The Nusselt number is shown to increase more than 400% in some cases with a decrease in porosity and an increase in Reynolds number. However, the pressure drop increases with decreasing permeability and increasing Reynolds number.
Raman Thermometry Measurements and Thermal Simulations for MEMS Bridges at Pressures From 0.05 Torr to 625 Torr
Authors: Phinney Leslie M. , Serrano Justin R. , Piekos Edward S. , Torczynski John R. , Gallis Michael A. , Gorby Allen D.
Published: May 2010

This paper reports on experimental and computational investigations into the thermal performance of microelectromechanical systems (MEMS) as a function of the pressure of the surrounding gas. High spatial resolution Raman thermometry was used to measure the temperature profiles on electrically heated, polycrystalline silicon bridges that are nominally 10 μm wide, 2.25 μm thick, and either 200 μm or 400 μm long in nitrogen atmospheres with pressures ranging from 0.05 Torr to 625 Torr (6.67 Pa–83.3 kPa). Finite element modeling of the thermal behavior of the MEMS bridges is performed and compared with the experimental results. Noncontinuum gas effects are incorporated into the continuum finite element model by imposing temperature discontinuities at gas-solid interfaces that are determined from noncontinuum simulations. The results indicate that gas-phase heat transfer is significant for devices of this size at ambient pressures but becomes minimal as the pressure is reduced below 5 Torr. The model and experimental results are in qualitative agreement, and better quantitative agreement requires increased accuracy in the geometrical and material property values.
High Rotation Number Effect on Heat Transfer in a Triangular Channel With 45 deg, Inverted 45 deg, and 90 deg Ribs
Authors: Liu Yao-Hsien , Huh Michael , Han Je-Chin , Moon Hee-Koo
Published: May 2010

Heat transfer and pressure drop have been experimentally investigated in an equilateral triangular channel (Dh=1.83 cm), which can be used to simulate the internal cooling passage near the leading edge of a gas turbine blade. Three different rib configurations (45 deg, inverted 45 deg, and 90 deg) were tested at four different Reynolds numbers (10,000–40,000), each with five different rotational speeds (0–400 rpm). The rib pitch-to-height (P/e) ratio is 8 and the height-to-hydraulic diameter (e/Dh) ratio is 0.087 for every rib configuration. The rotation number and buoyancy parameter achieved in this study were 0–0.58 and 0–2.3, respectively. Both the rotation number and buoyancy parameter have been correlated with predict the rotational heat transfer in the ribbed equilateral triangular channel. For the stationary condition, staggered 45 deg angled ribs show the highest heat transfer enhancement. However, staggered 45 deg angled ribs and 90 deg ribs have the higher comparable heat transfer enhancement at rotating condition near the blade leading edge region.
Direct Numerical Simulation of Near Field Thermal Radiation Based on Wiener Chaos Expansion of Thermal Fluctuating Current
Authors: Wen Sy-Bor
Published: May 2010

A methodology is proposed, which is capable of determining the near field thermal radiation based on the Wiener chaos expansion. The approach has no explicit constraints on the geometry and temperature distributions of the system and can be easily included with classical electrodynamics simulations. A specific application is made for the near field thermal radiation between two plates and the results are in very good agreement with the classical solutions obtained from Green’s function method. Also, by comparing the resulting solutions with the solutions from Green’s function method, a new point of view for interpreting the results for the near field thermal radiation in terms of a chaos expansion is provided.
Integrated Electronic Interconnection Solutions With Non-Woven Aramid
Authors: Gonzalez Ceferino G. , Khan Subhotosh , Weinhold Michael , Yen George
Published: May 2010

Every economic studies and OEM surveys show that communications and high-speed computing are the fastest growing electronics applications. The old rules for making these electronic devices are being broken such that whenever possible, space and weight are being saved, while still maintaining reliability and cost of the system. The consumer mobile phone exemplifies this technology trend. Many models are now equipped with personal organizers, multimedia, and wireless communications capabilities. To achieve these, there is much interest in homogeneous materials systems to improve mechanical and electrical performance from the semiconductor packaging to the assembled devices. System-on-chips (SOC), system-on-package (SOP), and rigid-bend-to-fit (3D) packaging are examples of the technologies being explored to get the most performance per space. Aramid substrates are used in 100% PWB and HDI microvia stack-ups in IC packaging, handheld devices, high-end computing, backplanes, and military/ avionics, while providing reliability and reduced overall costs. The talk will focus on why non-woven aramid substrates as homogeneous materials systems improve mechanical and electrical performance from the semiconductor packaging to the assembled devices. We will share data showing the versatility and applicability of aramid non-woven reinforced substrates impregnated with various resins, including why and how non-woven aramid substrates are laser ablateable; are able to be made thin and handleable, lightweight and bendable, thermally and dimensionally stable; and has low CTE able to be used in 100% PWB and HDI microvia stack-ups in IC packaging, handheld devices, high-end computing, backplanes, and military/ avionics, while providing reliability and reduced overall costs.
BCB Wafer Bonding Compatible With Bulk Micro Machining
Authors: Hwang Tao-Joo , Popa Dan O. , Lu Jian-Qiang , Kang Byoung-Hun , Stephanou Harry E.
Published: May 2010

Adhesive wafer bonding is a good substitute in wafer-to-wafer bonding applications requiring low processing temperatures and electrical potentials, though at the expense of difficulty with chemical, mechanical, and thermal stability over time. In the case of wafer bonding for Micro-Electro-Mechanical System (MEMS) applications, the problem is compounded not just by consideration of bond strength, but also by limitations in the way adhesives are delivered to the interface, since traditional spin-coating methods cannot be directly employed. A typical approach is the formation of micro-fluidic channels via wafer bonding, where the adhesive layer should only be present on the mesa structures. The introduction of BCB (benzocyclobutene), dry-etchable polymers, makes it possible to pattern the adhesive layer in a similar fashion with the rest of the bulk material. In this paper we present a BCB-based wafer bonding process, which is compatible with bulk micro machining. Depending on applications, BCB can replace the silicon oxide or silicon nitride as a hard mask in bulk micro machining. A process using BCB as both bonding adhesive and bulk-etch mask is a good option for stacking microstructures such as building micro-fluidic circuitry.
Deformation and Damage in Solder During Fast Cyclic Loading
Authors: Ege E. S. , Shen Y.-L.
Published: May 2010

Experimental and numerical studies on fast cyclic loading of eutectic tin-lead solder and relevant micromechanical issues are presented. High-frequency twin-lap shear tests on solder joints show cracking inside the solder but often connecting the intruded tips of the intermetallic. Finite element modeling was carried out to study the effect of intermetallic morphology. Without the influence of local phase coarsening, the intrusion of intermetallic into the solder alloy is seen to trigger strain localization which promotes failure. The effect of local phase coarsening was also studied numerically, taking into account the individual phase arrangement. A coarser phase structure always shows a faster accumulation of local plastic strain, leading to early failure. Such results, in agreement with typical thermomechanical fatigue features, cannot be obtained from the traditional argument of strength vs. microstructural size. Modeling of the entire lap-shear specimen was also conducted for the purpose of quantifying the deformation behavior. The exact geometry of solder is found to play a dominant role in affecting the shear response.
Analysis and Validation of Sensing Sensitivity of a Piezoresistive Pressure Sensor
Authors: Lin Chun-Te , Peng Chih-Tang , Lin Ji-Cheng , Chiang Kuo-Ning
Published: May 2010

In this study, a packaged silicon based piezoresistive pressure sensor is designed, fabricated, and studied. A finite element method (FEM) is adopted for designing and optimizing the sensor performance. Thermal as well as pressure loading on the sensor is applied to make a comparison between experimental and simulation results. Furthermore, a method that transfers the simulation stress data into output voltage is proposed in this study, and the results indicate that the experimental result coincides with the simulation data. In order to achieve better sensor performance, a parametric analysis is performed to evaluate the system output sensitivity of the pressure sensor. The design parameters of the pressure sensor include membrane size/shape and the location of piezoresistor. The findings depict that proper selection of the membrane geometry and piezoresistor location can enhance the sensor sensitivity.
A Broadband Wave Division Multiplexed (WDM) Local Area Network for Military Aircraft Using Commercial Off-the-Shelf (COTS) Components
Authors: Glista Andrew S. , Nahvi John
Published: May 2010

The US Naval Air Systems Command (NAVAIR) has recognized the need to rapidly test and evaluate (T&E) Generation II commercial, fiber optic and photonic components for use in harsh, military aerospace environments. This paper describes the Wavelength Division Multiplexed (WDM) Fiber-Optic Network (FON) demonstration program for the Navy EA-6B aircraft. The EA-6B Integrated Program Team is designing, developing and flight-testing a broadband fiber-optic Local Area Network (LAN) using ruggedized commercial WDM components and single mode cables and connectors. This WDM fiber optic backbone will be the first test demonstration of a network capable of simultaneously transferring both multi-protocol digital information and broadband radio frequency (RF) analog signals. Flight-testing of the digital portion of the system will take place on the EA-6B Tactical Electronic Attack aircraft with the support of NAVAIR at Patuxent River, MD. RF performance testing will take place at the Naval Air Warfare Center, Pt. Mugu California EA-6B Weapon System Support Laboratory. The first phase of this program [Flight Testing Optical Communication Using Open Standards (FOCUS) Phase I] demonstrated the survivability of Commercial Off-the-Shelf (COTS) fiber-optic single mode and multi-mode network hardware technology (cables, connectors, transmitters, receivers, encoders, decoders, and test equipment) on the EA-6B aircraft. The objective of the second phase of this program (FOCUS Phase II) is to design, develop, test and demonstrate, in the laboratory a (WDM ) network capable of simultaneously transmitting ultra wideband Radio Frequency (RF) analog signals as well as digital transmission protocols including Ethernet (10baseT), MIL-STD-1553, and ARINC-429 (et. al.) over a single fiber cable. The WDM FON system will then be installed and tested in the EA-6B aircraft. This paper will describe the backbone network design, which includes the network topology, test results on the proposed COTS components (lasers, couplers, add/drops, receivers etc.), and bandwidth allocation on the International Telecommunications Union (ITU) grid. Packaging of the COTS components to survive the extremely harsh military aircraft environment is also described.