bluuebunny/crossref_metadata_2025 huggingface dataset:
THE HEFNERIAN LEGACY: RETHINKING THE “NATURE” OF NATURALISM
Authors: Haag James W.
Published: February 2010

Philip Hefner calls for religion‐and‐science to shift attention from pure ideas to embodied ideas. He urges scholars to get back to the Baconian idea that science is intended to enhance life; in Hefner's wording, we must give attention to “science‐as‐enabler‐for‐changing/improving‐the‐world.” I believe that this is the realm of overlap between all academic disciplines—what I call thepragmatic overlap.To make his argument Hefner mentions two forms of “conventional wisdom” that need to be rethought. First, he is worried that a “pressure toward naturalism” prevents certain words (such asteleologicalandtranscendence) from having instructive meaning. Second, with this move toward naturalism Hefner believes we dismiss as archaic all valuable implications of traditional religious myths and symbols. He rightly highlights these exceedingly significant concerns. However, narrowing our focus to the implications of naturalism alone misses the root crisis. That crisis can be articulated as:“conventional wisdom” regarding nature is too unsophisticated to account for the phenomenon it depicts, and furthermore, this understanding of nature controls the methodological, metaphysical, and practical versions of naturalism acquiring societal acceptance.Accordingly, an alternative vision of nature is needed to transform our current “conventional wisdom” such that Hefner's worries are addressed.
Positive interactions between vulnerable species in agrarian pseudo‐steppes: habitat use by pin‐tailed sandgrouse depends on its association with the little bustard
Authors: Martín C. A. , Casas F. , Mougeot F. , García J. T. , Viñuela J.
Published: February 2010

Positive interactions between species can have important conservation implications, especially when the species associating are both vulnerable. We studied the habitat use of pin‐tailed sandgrouses Pterocles alchata and their association with another vulnerable species, the little bustard Tetrax tetrax in agrarian pseudo‐steppes of central Spain using radio‐tracking. The occurrence of mixed‐species flocks varied seasonally, being more frequent in winter (65% of pin‐tailed sandgrouse flocks). In this season, pin‐tailed sandgrouses preferred stubble fields and fallows. Moreover, we found that habitat selection of pin‐tailed sandgrouse depended on the association with little bustards in mixed‐species flocks. When in mixed‐species groups, sandgrouses changed their agrarian substrate preferences, and used stubble fields significantly more often than when in sandgrouse‐only flocks. We also provide evidence that pin‐tailed sandgrouse benefited from the anti‐predator vigilance of little bustards, allowing sandgrouse to exploit new feeding grounds (stubble fields) that would otherwise be too risky to exploit. Our results indicate a close positive association between these two species, which are both declining in Europe, and we discuss implications for their management and conservation. We also recommend taking into account inter‐specific positive interactions when designing conservation strategies for threatened species.
Multiple stressors on biotic interactions: how climate change and alien species interact to affect pollination
Authors: Schweiger Oliver , Biesmeijer Jacobus C. , Bommarco Riccardo , Hickler Thomas , Hulme Philip E. , Klotz Stefan , Kühn Ingolf , Moora Mari , Nielsen Anders , Ohlemüller Ralf , Petanidou Theodora , Potts Simon G. , Pyšek Petr , Stout Jane C. , Sykes Martin T. , Tscheulin Thomas , Vilà Montserrat , Walther Gian‐Reto , Westphal Catrin , Winter Marten , Zobel Martin , Settele Josef
Published: February 2010

Global change may substantially affect biodiversity and ecosystem functioning but little is known about its effects on essential biotic interactions. Since different environmental drivers rarely act in isolation it is important to consider interactive effects. Here, we focus on how two key drivers of anthropogenic environmental change, climate change and the introduction of alien species, affect plant–pollinator interactions. Based on a literature survey we identify climatically sensitive aspects of species interactions, assess potential effects of climate change on these mechanisms, and derive hypotheses that may form the basis of future research. We find that both climate change and alien species will ultimately lead to the creation of novel communities. In these communities certain interactions may no longer occur while there will also be potential for the emergence of new relationships. Alien species can both partly compensate for the often negative effects of climate change but also amplify them in some cases. Since potential positive effects are often restricted to generalist interactions among species, climate change and alien species in combination can result in significant threats to more specialist interactions involving native species.
Do agility and skull architecture influence the geometry of the mammalian vestibulo‐ocular reflex?
Authors: Jeffery Nathan , Cox Philip G.
Published: February 2010

The spatial arrangement of the semicircular canals and extraocular muscles of the eye has been of considerable interest, particularly to researchers working on adaptations of the vestibulo‐ocular reflex. Here we offer the first, extensive comparative analysis of the spatial relationships between each extraocular muscle and the canal providing its primary excitatory stimulus. The sample consisted of 113 specimens, representing 51 extant mammalian species. Hypotheses tested included that variations in the spatial alignments are linked with differences of skull morphology and with differences of agility during locomotion. Internal morphologies were visualized with magnetic resonance imaging and were measured with landmark‐based vectors and planes. Values for body mass and agility were taken from the existing literature. Data were investigated for trends and associations with standard bivariate and multivariate statistical methods as well as with phylogenetically adjusted bivariate methods. The findings clearly show that species differences in the alignment of each extraocular muscle relative to the canal providing its primary excitatory stimulus are closely associated with changes of orbit morphology. The results also indicate that the actions of the oblique muscles interchange with those of the superior and inferior recti muscles when comparing lateral‐eyed (rabbit) with frontal‐eyed species (cat). There was only weak evidence to support the notion that canal–muscle alignments differ significantly among species according to how agile they are. The results suggest that semicircular canal morphology is arranged primarily for detecting head movements and then secondarily, if at all, for diminishing the burden of transforming vestibulo‐ocular reflex signals in the most agile species.
Test‐retest reliability of balance tests in children with cerebral palsy
Authors: Liao Hua‐Fang , Mao Pai‐Jun , Hwang Ai‐Wen
Published: February 2010

To investigate intrasession and intersession reliability of balance tests in children with or without disabilities, 50 children without disabilities (ND) and 36 children with cerebral palsy (CP) aged from 5 to 12 years were tested. Intrasession reliability of postural stability of the Smart Balance Master System and one‐leg standing test were assessed in both groups and intersession reliability of the Smart Balance Master System and balance subtest of the Bruininks‐Oseretsky Test of Motor Proficiency (BOTMP) were assessed in ND children. Intersession reliability of the postural stability test in ND children, obtained using the Smart Balance Master System, was of moderate to good reliability in centre target (CT), sway vision (SV), eyes open and sway surface (EOSS), and sway vision and sway surface (SVSS; ICC 0.72 to 0.84). In children with CP, intrasession reliability was high in CT (ICC 1). One‐leg standing tests in both groups also had moderate to good intersession reliability (ICC 0.56 to 0.99). Agreement of failure score of lateral rhythmic shifting (LRS) at 1 second and 2 seconds pace was 85% and 93% respectively in ND children. Within the balance subtest of BOTMP, only two items had 100% agreement. Results suggest that postural stability tests in four conditions (CT, SV, EOSS, and SVSS), LRS, one‐leg standing, and walking on a line are reliable and can be used to monitor balance control in ND children. Postural stability in CT condition and one‐leg standing test are reliable in children with CP. Further study is needed to establish more reliable balance tests for children with CP.
Fetal valproate syndrome and autism: additional evidence of an association
Authors: Williams Gail , King John , Cunningham Michael , Stephan Mark , Kerr Bronwyn , Hersh Joseph H
Published: February 2010

Autism has been described in association with a variety of medical and genetic conditions. We previously reported on a patient whose clinical phenotype was compatible with both fetal valproate syndrome (FVS) and autism. Here we present five additional patients with FVS and autism. In all five of our patients, there was evidence of cognitive deficits, manifestations of autism, and typical phenotypic characteristics of FVS. The association between this known teratogen and autism has both clinical and research implications.
The Behavioural Wedge
Authors: Gilligan Jonathan , Dietz Thomas , Gardner Gerald T. , Stern Paul C. , Vandenbergh Michael P.
Published: February 2010

When nations fail to agree, can individual citizens make a difference? The third of our post-Copenhagen features is by Jonathan Gilligan, Thomas Dietz, Gerald T. Gardner, Paul C. Stern, and Michael P. Vandenbergh. They look at the effects that voluntary actions by individuals can have, and at the policies that can best encourage such actions.
On the thermodynamic equilibrium between (R)‐2‐hydroxyacyl‐CoA and 2‐enoyl‐CoA
Authors: Parthasarathy Anutthaman , Buckel Wolfgang , Smith David M.
Published: February 2010

A combined experimental and computational approach has been applied to investigate the equilibria between several α‐hydroxyacyl‐CoA compounds and their 2‐enoyl‐CoA derivatives. In contrast to those of their β, γ and δ counterparts, the equilibria for the α‐compounds are relatively poorly characterized, but qualitatively they appear to be unusually sensitive to substituents. Using a variety of techniques, we have succeeded in measuring the equilibrium constants for the reactions beginning from 2‐hydroxyglutaryl‐CoA and lactyl‐CoA. A complementary computational evaluation of the equilibrium constants shows quantitative agreement with the measured values. By examining the computational results, we arrive at an explanation of the substituent sensitivity and provide a prediction for the, as yet unmeasured, equilibrium involving 2‐hydroxyisocaproyl‐CoA.
Preparation and Characterization of Fiber‐Reinforced Aluminum Phosphate/Silica Composites with Interpenetrating Phase Structures
Authors: Deng Shifeng , Wang Canfeng , Zhou Yan , Huang Farong , Du Lei
Published: February 2010

Glass fiber‐reinforced aluminum phosphate (AP)/silica composites were prepared by hydrolyzing tetraethylorthosilicate (TEOS) in AP binder. The composites were hot pressed and cured at a temperature range between 140°C and 200°C with Al2O3 as a curing agent. Microstructures of the prepared composites were examined using scanning electron microscopy. Flexural properties of the composites were investigated by a three‐point bending test. It was found that the flexural strength of the prepared composites was significantly increased when appropriate concentrations of TEOS were used for hydrolysis. A microstructure study demonstrated that the improvement in flexural strength was due to the formation of an interpenetrating network structure between the two inorganic phases.
The black hole in NGC 1313 X-2: constraints on the mass from optical observations
Authors: Patruno Alessandro , Zampieri Luca
Published: February 2010

We present a theoretical study on the nature of the ultraluminous X-ray source NGC 1313 X-2. We evolved a set of binaries with high-mass donor stars orbiting a 20 M⊙ or a 50–100 M⊙ black hole (BH). Using constraints from optical observations, we restricted the candidate binary system for NGC 1313 X-2 to be either a 50–100 M⊙ BH accreting from a 12–15 M⊙ main-sequence star or a ∼20 M⊙ BH with a 12–15 M⊙ giant donor. If the modulation of 6.12 ± 0.16 d recently identified as the orbital period of the system is confirmed, a ∼20 M⊙ BH model becomes unlikely and we are left with the only possibility that the compact accretor in NGC 1313 X-2 is a massive BH of ∼50–100 M⊙.
STUDY ON PRESTABILIZATION OF PUMPKIN (CUCURBITA MOSCHATA) BY OSMOTIC DEHYDRATION IN QUATERNARY COMPLEX SOLUTION
Authors: DEROSSI A. , DE PILLI T. , GIULIANI R. , ORLANDO I. , PALMIERI L. , SEVERINI C.
Published: February 2010

Pumpkin is a very appreciated vegetable for both unique sensory characteristics and significant content of substances with healthy effects. Very few “pumpkin‐processed foods” with adequate shelf life are available on the market because of poor knowledge relative to its behavior during industrial processes. The possibility to reduce water activity (Aw) and pH of pumpkin samples by osmotic treatment in complex (quaternary) solution was studied by response‐surface methodology (RSM). The reduction of pH and Aw until values recognized as safe for spore germination of Clostridium botulinum and Clostridium perfringens was respectively obtained without significant color degradation. Moreover, the modulation of the independent variables, carried out by using the best‐fit equation, was aimed at prestabilizing pumpkin creams.

PRACTICAL APPLICATIONS

The poor knowledge concerning the behavior of pumpkins during industrial processing reduces their uses to produce a variety of “pumpkin food” with adequate shelf life. In this article, the possibility of applying an osmotic treatment in a complex (quaternary) solution in order to simultaneously obtain a reduction in water activity (Aw) and pH was presented. In addition, the utilization of model equation allows the simulation of osmotic dehydration, giving information on the process conditions usable to reach Aw and pH values recognized as risk threshold for spore germination of Clostridium botulinum and Clostridium perfringens.
Concurrent and disconnected change programmes: strategies in support of servitization and the implementation of business partnering
Authors: Raja Jawwad Z. , Green Stuart D. , Leiringer Roine
Published: February 2010

For many leading engineering companies, the integration of services into product offerings is seen to comprise an important shift in the underlying business model. This movement has been termed the ‘servitization of business’. Within this debate, however, scant attention has been given to the human resource (HR) implications of servitization. An exploratory case study illustrates the HR challenges associated with servitization and the way in which these interact with a concurrent change programme concerned with the implementation of ‘business partnering’. The findings highlight the emergent complexities resulting from these two change programmes being rolled out simultaneously. Although contested across different divisions, the shift to servitization continuously disrupts the implementation of business partnering with little alignment between the two espoused initiatives. Furthermore, the rate of strategic change within the company in response to changing markets continuously acts to erode the coherence of the acclaimed move to business partnering. In consequence, the HR policies and practices struggle to maintain contact with the company's strategic direction.
Employee involvement and group incentives in manufacturing companies: a multi‐level analysis
Authors: Park Rhokeun , Appelbaum Eileen , Kruse Douglas
Published: February 2010

The effects of employee involvement and group incentives on organisational commitment and turnover intention were examined using data from a survey of over 4,000 employees in 29 manufacturing companies. Using the mediated moderation model, we investigated the moderating role of capital intensity on the relationships between employee involvement and group incentives and these outcomes, and the mediating role of organisational commitment on the effects of employee involvement and group incentives on turnover intention. The findings revealed that employee involvement is more effective in capital‐intensive companies than in labour‐intensive companies, but group incentives are more effective in labour‐intensive companies. The moderated effects on turnover intention were mediated through organisational commitment. Implications for company policies and future research are discussed.
The integrative aspects of cardiac physiology and their implications for cell‐based therapy
Authors: Pijnappels Daniël A. , Gregoire Serge , Wu Sean M.
Published: February 2010

Cardiac development is characterized by a complex interplay of chemical, mechanical, and electrical forces, which together contribute to the proper formation of the heart muscle. In adult myocardium, cardiomyocytes are elongated, well‐coupled by gap junctions, and organized in spatially well‐defined muscle fibers. This specific tissue architecture affects electromechanical activation and global cardiac function. Since the adult heart has only limited capacity for repair after injury, a significant loss of myocardial tissue often leads to impaired cardiac function. Recent efforts to transplant autologous cells to counteract this cardiomyocyte loss have resulted in marginal functional improvement and no evidence of myocyte regeneration. In order to achieve durable therapeutic efficiency, the transplanted cells will need to not only be cardiomyogenic, but also functionally integrate with host myocardial tissue and thereby contribute to both structural and functional restoration.
The role of mechanical forces in the torsional component of cardiac looping
Authors: Taber Larry A. , Voronov Dmitry A. , Ramasubramanian Ashok
Published: February 2010

During early development, the initially straight heart tube (HT) bends and twists (loops) into a curved tube to lay out the basic plan of the mature heart. The physical mechanisms that drive and regulate looping are not yet completely understood. This paper reviews our recent studies of the mechanics of cardiac torsion during the first phase of looping (c‐looping). Experiments and computational modeling show that torsion is primarily caused by forces exerted on the HT by the primitive atria and the splanchnopleure, a membrane that presses against the ventral surface of the heart. Experimental and numerical results are described and integrated to propose a hypothesis for cardiac torsion, and key aspects of our hypothesis are tested using experiments that perturb normal looping. For each perturbation, the models predict the correct qualitative response. These studies provide new insight into the mechanisms that drive and regulate cardiac looping.
Epigenetics in heart failure
Authors: Papait Roberto , Condorelli Gianluigi
Published: February 2010

Heart failure is one of the main causes of mortality in developed countries and is frequently associated with cardiac hypertrophy. Gene expression reprogramming in cardiac myocytes is a key feature of heart hypertrophy and failure and is characterized by upregulation of fetal genes and decreased expression of some subsets of adult ones. The full picture of signaling events underlying gene transcription in these pathophysiologic states is not completely understood, but recent evidence suggests a major role for epigenetics. This report provides an overview of the mechanisms of epigenetics and how they affect myocardial gene expression during hypertrophy and failure.
Noninvasive imaging of cardiac electrophysiology and arrhythmia
Authors: Rudy Yoram
Published: February 2010

Cardiac arrhythmias are a major cause of death and disability. Despite the clinical need and the importance of studying arrhythmia mechanisms in humans, a noninvasive imaging modality for cardiac electrophysiology is not yet available for routine application. Here we describe such a noninvasive imaging modality, electrocardiographic imaging (ECGI), and provide examples of its application in various (normal and abnormal) cardiac rhythms.
Cross‐amplification of microsatellites from the codling moth Cydia pomonella to three other species of the tribe Grapholitini (Lepidoptera: Tortricidae)
Authors: CHEN M. H. , DORN S.
Published: February 2010

This study examined cross‐species amplification of 33 microsatellite markers, previously developed for Cydia pomonella, in three related fruit moth species of the same tribe (Grapholitini), namely Grapholita molesta, Grapholita funebrana and Grapholita lobarzewskii. Eight microsatellite loci yielded polymorphic products for G. molesta, nine for G. funebrana and 11 for G. lobarzewskii. At all these loci, the number of alleles ranged between four and 11 in G. molesta, and between four and nine in G. funebrana and G. lobarzewskii each. The successful cross‐amplified loci can be used for research on population genetics and gene flow of the three target species.
A Primer on Child Abuse and Neglect Law
Authors: Ramsey Sarah H. , Abrams Douglas E.
Published: February 2010

This article surveys major aspects of child abuse and neglect law encountered by judges, lawyers, child advocates, and child care professionals. The authors, whose casebook, Children and the Law: Doctrine, Policy and Practice (West 4th ed. forthcoming 2010), is required reading in nearly seventy law schools, analyze both statutory and case law.
Globally disseminated human pathogenic Escherichia coli of O25b‐ST131 clone, harbouring blaCTX‐M‐15, found in Glaucous‐winged gull at remote Commander Islands, Russia
Authors: Hernandez Jorge , Bonnedahl Jonas , Eliasson Ingvar , Wallensten Anders , Comstedt Pär , Johansson Anders , Granholm Susanne , Melhus Åsa , Olsen Björn , Drobni Mirva
Published: February 2010

With focus on environmental dissemination of antibiotic resistance among clinically relevant bacteria, such as the rising ESBL type of resistance among Escherichia coli, we investigated antibiotic resistance levels in wild birds in the Commander Islands and Kamchatka, Russia. Despite overall low resistance levels in randomly selected E. coli (one from each sample), we found multi‐resistant ESBL‐producing E. coli harbouring blaCTX‐M‐14 and blaCTX‐M‐15 using selective screening. Among these multi‐resistant ESBL‐producing E. coli we found one blaCTX‐M‐15 harbouring strain belonging to the O25b‐ST131 clone, recognized for its clonal disseminated worldwide as a human pathogen. The potential in acquiring resistant bacteria of human origin, especially highly pathogenic clones, as well as downstream consequences of that, should not be underestimated but further investigated.
On semi-infinite cohomology of finite-dimensional graded algebras
Authors: Bezrukavnikov Roman , Positselski Leonid
Published: February 2010

We describe a general setting for the definition of semi-infinite cohomology of finite-dimensional graded algebras, and provide an interpretation of such cohomology in terms of derived categories. We apply this interpretation to compute semi-infinite cohomology of some modules over the small quantum group at a root of unity, generalizing an earlier result of Arkhipov (posed as a conjecture by B. Feigin).
Low‐dose dexamethasone prevents endotoxaemia‐induced muscle protein loss and impairment of carbohydrate oxidation in rat skeletal muscle
Authors: Crossland Hannah , Constantin‐Teodosiu Dumitru , Greenhaff Paul L. , Gardiner Sheila M.
Published: February 2010

We recently provided evidence suggesting a role for cytokine‐mediated inhibition of Akt/Forkhead box O 1 (FOXO1) signalling in the induction of muscle atrophy and impairment of muscle carbohydrate oxidation during lipopolysaccharide (LPS)‐induced endotoxaemia in rats. We hypothesized that a low‐dose dexamethasone (Dex; anti‐inflammatory agent) infusion during endotoxaemia would prevent the LPS‐induced impairment of Akt/FOXO1 signalling, and therefore prevent the muscle atrophy and impairment of carbohydrate oxidation. Chronically instrumented Sprague–Dawley rats received a continuous intravenous infusion of LPS (15 μg kg−1 h−1), Dex (12.5 μg kg−1 h−1), Dex+LPS or saline for 24 h at 0.4 ml h−1. LPS infusion caused haemodynamic changes consistent with a hyperdynamic circulation and induced increases in muscle tumour necrosis factor‐α (TNF‐α; 10‐fold, P < 0.001), interleukin‐6 (IL‐6; 14‐fold, P < 0.001) and metallothionein‐1A (MT‐1A; 187‐fold, P < 0.001) mRNA expression. Dex co‐administration abolished most of the haemodynamic effects of LPS and reduced the increase in muscle TNF‐α, IL‐6 and MT‐1A by 51% (P < 0.01), 85% (P < 0.001) and 58% (P < 0.01), respectively. Dex infusion during endotoxaemia also prevented the LPS‐induced 40% reduction in the muscle protein:DNA ratio and decrease in Akt phosphorylation, and partially prevented the reduction in FOXO1 phosphorylation. However, Dex did not prevent the LPS‐mediated increase in muscle atrophy F‐box (MAFbx) and muscle RING finger 1 (MuRF1) mRNA expression, but did significantly reduce the LPS‐mediated increase in cathepsin‐L mRNA expression and enzyme activity by 43% (P < 0.001) and 53% (P < 0.05), respectively. Furthermore, Dex suppressed LPS‐induced pyruvate dehydrogenase kinase 4 (PDK4) mRNA upregulation by ∼50% (P < 0.01), and prevented LPS‐mediated muscle glycogen breakdown and lactate accumulation. Thus, low‐dose Dex infusion during endotoxaemia prevented muscle atrophy and the impairment of carbohydrate oxidation, potentially through suppression of cytokine‐mediated Akt/FOXO inhibition, and blunting of cathepsin‐L‐mediated lysosomal protein breakdown.
Flow Boiling on Micropin Fins Entrenched Inside a Microchannel—Flow Patterns and Bubble Departure Diameter and Bubble Frequency
Authors: Krishnamurthy Santosh , Peles Yoav
Published: February 2010

Flow boiling of HFE 7000 in five parallel microchannels of 222 μm hydraulic diameter, each containing a single row of 24 in-line 100 μm pin fins, was investigated. High speed photography revealed the dominant flow patterns, namely, the bubbly flow, the multiple flow, and the wavy-annular flow. The interaction of the bubble with the pin fins during nucleate boiling from G=350 kg/m2 s to G=827 kg/m2 s and wall heat fluxes from 10 W/cm2 to 110 W/cm2 is detailed.
Flow Boiling Heat Transfer on Micro Pin Fins Entrenched in a Microchannel
Authors: Krishnamurthy Santosh , Peles Yoav
Published: February 2010

Flow boiling of 1-methoxyheptafluoropropane (HFE 7000) in 222 μm hydraulic diameter channels containing a single row of 24 inline 100 μm pin fins was studied for mass fluxes from 350 kg/m2 s to 827 kg/m2 s and wall heat fluxes from 10 W/cm2 to 110 W/cm2. Flow visualization revealed the existence of isolated bubbles, bubbles interacting, multiple flow, and annular flow. The observed flow patterns were mapped as a function of the boiling number and the normalized axial distance. The local heat transfer coefficient during subcooled boiling was measured and found to be considerably higher than the corresponding single-phase flow. Furthermore, a thermal performance evaluation comparison with a plain microchannel revealed that the presence of pin fins considerably enhanced the heat transfer coefficient.
Representative Results for Condensation Measurements at Hydraulic Diameters ∼100 Microns
Authors: Agarwal Akhil , Garimella Srinivas
Published: February 2010

Condensation pressure drops and heat transfer coefficients for refrigerant R134a flowing through rectangular microchannels with hydraulic diameters ranging from 100 μm to 200 μm are measured in small quality increments. The channels are fabricated on a copper substrate by electroforming copper onto a mask patterned by X-ray lithography and sealed by diffusion bonding. Subcooled liquid is electrically heated to the desired quality, followed by condensation in the test section. Downstream of the test section, another electric heater is used to heat the refrigerant to a superheated state. Energy balances on the preheaters and postheaters establish the refrigerant inlet and outlet states at the test section. Water at a high flow rate serves as the test-section coolant to ensure that the condensation side presents the governing thermal resistance. Heat transfer coefficients are measured for mass fluxes ranging from 200 kg/m2 s to 800 kg/m2 s for 0< quality <1 at several different saturation temperatures. Conjugate heat transfer analyses are conducted in conjunction with local pressure drop profiles to obtain accurate driving temperature differences and heat transfer coefficients. The effects of quality, mass flux, and saturation temperature on condensation pressure drops and heat transfer coefficients are illustrated through these experiments.
Using Direct Simulation Monte Carlo With Improved Boundary Conditions for Heat and Mass Transfer in Microchannels
Authors: Yang J. , Ye J. J. , Zheng J. Y. , Wong I. , Lam C. K. , Xu P. , Chen R. X. , Zhu Z. H.
Published: February 2010

Micro-electromechanical systems and nano-electromechanical systems have attracted a great deal of attention in recent years. The flow and heat transfer behaviors of micromachines for separation applications are usually different from that of macro counterparts. In this paper, heat and mass transfer characteristics of rarefied nitrogen gas flows in microchannels are investigated using direct simulation Monte Carlo with improved pressure boundary conditions. The influence of aspect ratio and wall temperature on mass flowrate and wall heat flux in microchannels are studied parametrically. In order to examine the aspect ratio effect on heat and mass transfer behaviors, the wall temperature is set constant at 350 K and the aspect ratio of the microchannel varies from 5 to 20. The results show that as the aspect ratio increases, the velocity of the flow decreases, so does the mass flowrate. In a small aspect ratio channel, the heat transfer occurs throughout the microchannel; as the aspect ratio of the microchannel increases, the region of thermal equilibrium extends. To investigate the effects of wall temperature (Tw) on the mass flowrate and wall heat flux in a microchannel, the temperature of the incoming gas flow (Tin) is set constant at 300 K and the wall temperature varies from 200 K to 800 K while the aspect ratio is remained unchanged. Results show that majority of the wall heat flux stays within the channel entrance region and drops to nearly zero at the halfway in the channel. When Tw<Tin, under the restriction of pressure-driven condition and continuity of pressure, the molecular number density of the flow decreases along the flow direction after a short increase at the entrance region. When Tw>Tin, the molecular number density of the flow drops rapidly near the inlet and the temperature of the gas flow increases along the channel. As Tw increases, the flow becomes more rarefied, the mass flowrate decreases, and the resistance at the entrance region increases. Furthermore, when Tw>Tin, a sudden jump of heat transfer flux and temperature are observed at the exit region of the channel.
Analytical Modeling of Annular Flow Boiling Heat Transfer in Mini- and Microchannel Heat Sinks
Authors: Megahed A. , Hassan I.
Published: February 2010

An analytical model is proposed to predict the flow boiling heat transfer coefficient in the annular flow regime in mini- and microchannel heat sinks based on the separated model. The modeling procedure includes a formulation for determining the heat transfer coefficient based on the wall shear stress and the local thermophysical characteristics of the fluid based on the Reynolds’ analogy. The frictional and acceleration pressure gradients within the channel are incorporated into the present model to provide a better representation of the flow conditions. The model is validated against collected data sets from the literature produced by different authors under different experimental conditions, different fluids, and with mini- and microchannels of hydraulic diameters falling within the range of 92–1440 μm. The accuracy between the experimental and predicted results is achieved with a mean absolute error of 10%. The present analytical model can correctly predict the different trends of the heat transfer coefficient reported in the literature as a function of the exit quality. The predicted two-phase heat transfer coefficient is found to be very sensitive to changes in mass flux and saturation temperature. However, it is found to be mildly sensitive to the change in heat flux.
A New Knotless Suture Staple Double Row Construct for Medial Repair of Rotator Cuff Tears
Authors: Schlegel Theodore F. , Otarodifard Karimdad Amir , Hawkins Richard J. , Vangsness Thomas , Bui Christopher , McGarry Michelle H. , Lee Thay Q.
Published: February 2010

Recently, there has been considerable interest in the ability to repair the rotator cuff tendon to its anatomic site along the articular margin of the footprint for either double row repairs or with a PASTA lesion. Unfortunately, this can often be difficult to perform since it requires placing a fixation device at the articular margin and then bringing sutures through the rotator cuff tendon. A new technology allows for easy piercing of the rotator cuff tendon under direct visualization with simultaneous placement of the anchoring device. The second preloaded anchor can then be used to create a suture bridge over the tendon for tensioning and eventual security without tying knots. We hypothesized that suture staple double row repair with a knotless anchoring system along with a traditional lateral row fixation has similar biomechanical characteristics to the TOE rotator cuff repair. Therefore, the objective of this study was to quantify and compare the biomechanical characteristics of a knotless suture staple double row (SSDR) repair and transosseous equivalent (TOE) rotator cuff repair using matched pair shoulders.
Hip Arthroscopy: The Next Frontier in Orthopaedic Surgery and Its Challenges
Authors: Safran Marc R.
Published: February 2010

Hip Arthroscopy is the most rapidly growing field in Orthopaedic Surgery. The volume of hip arthroscopy has tripled since 2003. Yet, despite the rapid recent growth, it is felt that only 10% of problems that can be treated with hip arthroscopy are currently being done so. The reasons for this are multiple — lack of recognition of problems in the hip by those not experienced with non-arthritic hip problems, insufficient numbers of surgeons trained to do hip arthroscopy, and, not unimportantly, the difficulty of performing hip arthroscopy. One of the most common underlying problems affecting individuals with non-arthritic hip pain is femoroacetabular impingement (FAI). FAI was first described by Ganz in the Swiss literature in 1995, and did not make it into the English literature until 1999. Due to its very recent identification, acceptance of this problem and dissemination to clinicians has resulted in a relatively low number of clinicians being aware of this problem.
Design and Testing of a Hydrogen Fuel Cell Powered Motorcycle
Authors: Bell Alex , Pacheco Andres , Macken Nelson
Published: February 2010

The goal of the project was to design and build a hydrogen fuel cell powered motorcycle to provide efficiency data as well as increase knowledge and interest in fuel cell based propulsion. Presented are details on the structural components, the fuel cell stack, the metal hydride hydrogen storage tanks, the power electronics drive and the data acquisition system. Waste heat from the fuel cells is used to significantly improve the storage capacity of the metal hydride tanks. Data and analysis of bench and road tests are presented.
On the Efficiency of Compressors With Diabatic Flows
Authors: Casey Michael V. , Fesich Thomas M.
Published: February 2010

In most compressors the flow is adiabatic, but in micro-compressors, and in turbochargers at low speeds, the compression process has both heat transfer and work input. The classical adiabatic efficiency definition found in most text books is then incorrect. This paper extends the text book definitions of compressor efficiency to diabatic flows. The paper explains different compressor efficiency definitions in a logical way and identifies fundamental flaws in the use of isentropic efficiency for a diabatic flow. It shows that the polytropic efficiency can be used with or without heat transfer without ambiguities. Other significant advantages of the polytropic efficiency are also summarized, as they are not fully covered in any turbomachinery text books. The advantages of the polytropic approach for a practical application are demonstrated by analyzing the heat transfer in a turbocharger compressor. A simple model of the heat transfer allows a correction for this effect on the polytropic efficiency at low speed to be derived. Compressor characteristics that have been corrected for this surprisingly large effect maintain a much higher efficiency down to low speeds.
Effective Area and Effective Volume Calculations for Ceramic Test Specimens
Authors: Jain Rahul , Lock James , Duffy Stephen F.
Published: February 2010

The calculation of the effective volume and/or effective area is a key step in estimating the reliability of ceramic component life cycles. Most common tests performed to assess the strength of components made from ceramics are bend bar specimens tested in three-point and four-point flexure, C-ring and O-ring specimens under diametral compressive or tensile loads, and biaxial ring-on-ring specimens. ASTM closed form solutions [1] for the effective volume and area exist for specimen geometries based on classical theories with underlying assumptions. In general, the closed form expressions are valid for limited specimen geometry bounds. A discussion regarding the validity is presented via a numerical approach that computationally determines the effective volume and area for ceramic test specimens. The results obtained utilizing the numerical approach are compared with the closed form solutions. These comparisons point to the need for revisiting the underlying assumptions used in developing the closed form expressions. Finally, simple power law approximations are developed based on numerical results that directly give the effective volume and/or the effective area based on the Weibull modulus for the test geometries investigated in this research effort.
Micro Gas Turbine Real-Time Modeling: Test Rig Verification
Authors: Ghigliazza Francesco , Traverso Alberto , Pascenti Matteo , Massardo Aristide F.
Published: February 2010

This paper reports on the latest application of a generic time-dependent real-time simulation tool, originally developed for fuel cell gas turbine hybrid systems, and now applied to an actual micro gas turbine test rig. Real-time modeling is a recognized approach for monitoring advanced systems and improving control capabilities: applications of real-time models are commonly used in the automotive and aircraft fields. The overall objective is improving of calculation time in existing time-dependent simulation models, while retaining acceptable accuracy of results. The real-time modeling approach already applied to fuel cell gas turbine systems has here been validated against the experimental data from the micro gas turbine Turbec T100 test rig in Savona, Italy. The real-time model of the microturbine recuperator has been newly developed to fit such an application. Two representative transient operations have been selected for verification: the heating and cooling phases of the connected volume. The results already show an acceptable agreement with measurements, and they have contributed to a better insight into performance prediction for the entire plant.
Gas Turbine Performance and Health Status Estimation Using Adaptive Gas Path Analysis
Authors: Li Y. G.
Published: February 2010

In gas turbine operation, engine performance and health status is very important information for engine operators. Such engine performance is normally represented by engine air flow rate, compressor pressure ratios, compressor isentropic efficiencies, turbine entry temperature, turbine isentropic efficiencies, etc. while the engine health status is represented by compressor and turbine efficiency indices and flow capacity indices, etc. However, these crucial performance and health information can not be directly measured and therefore are not easily available. In this research, a novel Adaptive Gas Path Analysis (Adaptive GPA) approach has been developed to estimate actual engine performance and gas path component health status by using gas path measurements, such as gas path pressures, temperatures, shaft rotational speeds, fuel flow rate, etc. Two steps are included in the Adaptive GPA approach, the first step is the estimation of degraded engine performance status by a novel application of a performance adaptation method and the second step is the estimation of engine health status at component level by using a new diagnostic method introduced in this paper based on the information obtained in the first step. The developed Adaptive GPA approach has been tested in four test cases where the performance and degradation of a model gas turbine engine similar to Rolls-Royce aero engine AVON-300 have been analyzed. The case studies have shown that the developed novel linear and non-linear Adaptive GPA approach can accurately and quickly estimate the degraded engine performance and predict the degradation of major engine gas path components with the existence of measurement noise. The test cases have also shown that the calculation time required by the approach is short enough for its potential online applications.
Pilot-Premix Flames: Higher Operational Flexibility in Gas Turbines Without NOx Increase
Authors: Albrecht Peter , Bade Stefanie , Paschereit Christian Oliver , Dinkelacker Friedrich , Gutmark Ephraim
Published: February 2010

A premixed pilot injection with reduced NOx formation is proposed as a fail-safe and simple control method to extend the operating range of gas turbines. Different pilot locations within the combustion chamber were chosen to see the impact of pilot injection flames on the local extinction behavior and on the NOx formation. The pilot flame injector (PFI) represents a device for premixed pilot injection and was located in the center of the swirl burner cone. Moreover, the premixed pilot could be ignited by an embedded spark plug inside the PFI so that the main flame, especially near the lean limit, can be provided with additional radicals at the lower stagnation point of the central recirculation zone. A second pilot injection was located at the combustor dump to inject the pilot fuel/air mixture axially into the shear layer between the central and side recirculation zone. It could be shown for different main air preheat temperatures and with activated PFI flame (at 110 Hz spark frequency), that the premixed pilot is the most efficient control method for local extinction prevention without CO emission increase. Also the NOx emissions keep on similar level as the baseline case. The spark plug might also be replaced by a laser ignition device. The efficiency of laser spark plugs could be already demonstrated under atmospheric conditions in Moesl2008 [1] where different ignition devices are proposed to ignite a swirl-stabilized kerosine mixture. Moreover, former tests with the PFI flame indicate also a method to control instabilities so that high amplitude of p′ oscillations could be suppressed.
An Assessment of the Emissions and Global Warming Potential of Gas Turbines for LNG Applications
Authors: Khan Raja S. R. , Barreiro Javier , Lagana Maria Chiara , Kyprianidis Konstantinos G. , Ogaji Stephen O. T. , Pilidis Pericles , Bennett Ian
Published: February 2010

This paper concentrates on the emissions module of what is part of a wider project dealing with various aspects of gas turbine usage as drivers for Liquefied Natural Gas (LNG) production. The framework is known as TERA, a Techno-Economic and Environmental Risk Analysis, developed at Cranfield University with the core of the study being the performance module whilst the risk, economics and environmental modules are built around the performance. Whilst TERA exists for aviation and power production no such system is available for assessment of LNG production. With environmental issues high on the public agenda new legislation on emissions can be expected, especially in Europe. This will mean Oil & Gas companies will have to look for ways to reduce their emissions. One way to reduce turbo machinery losses is to replace out dated and/or obsolete machinery having less overall energy efficiency. The selection of turbomachinery involves assessments of risk, both economic and technical, as well as environmental impacts of the new technology. The core to all of this is the performance assessment, the primary basis on which selection is made. An aviation emissions model, developed at Cranfield University, is adapted for industrial applications. Technical performance calculations are made using the inhouse software called Turbomatch. Performance results for three typical days of the year (summer, winter and spring/autumn) are fed into the emissions model to get the levels of NOx, CO2, H2O, CO and unburnt hydrocarbon emissions. Later, NOx, CO2 and H2O emissions levels are fed into the environmental module to estimate the damage the engine causes to the environment over 100 years with respect to global warming. Two hypothetical engine configurations are investigated based on engine data available in the public domain. The first one, an 85MW single spool industrial machine (SSI-85), is used as the baseline to compare against a 100MW triple spool, intercooled aeroderivative (ITSA-100). The results suggest that the ITSA-100 produces more NOx but has less carbon emissions and consequently less global warming effects. This has varied economic impacts depending on which emission is a priority for reduction. CO2 and H2O emissions are more important than NOx for LNG gas turbine applications. The paper shows how this simple but effective system can be utilised to give a viable comparison between one or more proposed solutions for turbomachinery selection and replacement. The scope of the system is expanded as other modules come together to give a total assessment in terms of technical, economic, environmental and risk perspectives for LNG production.
Effect of Casing Treatment and Variable Axial Guide Vanes on a Turbocharger Compressor Performance
Authors: Mohtar Hani , Chesse Pascal , Chalet David , Yammine Anthony
Published: February 2010

Engine downsizing is potentially one of the most effective strategies being explored to improve fuel economy. A main problem of downsizing using a turbocharger is the small range of stable functioning of the turbocharger centrifugal compressor at high boost pressures. Several stabilization techniques were studied to increase the compressor operating range without sacrificing the compressor efficiency. This paper presents an experimental study on a turbocharger compressor equipped with casing treatment (a map width enhancement system, MWE) and a variable inlet guide vane system (VIGV). A KKK turbocharger was modified and tested at Ecole Centrale de Nantes. The experimental program mainly dealt with traditional compressor performance measurements for an MWE (map width enhancement) structure with multitude of holes linking the annular flow passage and the impeller wheel, four different inner tubular length extensions and imparting positive and negative preswirl using VIGV system. The experimental studies have shown that while the MWE was advantageous in increasing pressure ratio at high compressor speeds, it failed in extending the compressor map. The different inner tubular length extensions have shown no significant effects on surge line improvement for this particular design. Results obtained from MWE system have been compared to those obtained when imparting positive and negative preswirl using an VIGV system.