bluuebunny/crossref_metadata_2025 huggingface dataset:
Expression of zinc finger protein 105 in the testis and its role in male fertility
Authors: Zhou Huaxin , Liu Lan‐Hsin , Zhang Heng , Lei Zhenmin , Lan Zi‐Jian
Published: February 2010

Using an in silico approach, we identified a putative zinc finger domain‐containing transcription factor (zinc finger protein 105, ZFP105) enriched in the adult mouse testis. RT‐PCR analyses showed that Zfp105 was indeed highly expressed in adult mouse testis and that its expression was regulated during postnatal development. To further characterize Zfp105 expression, we generated a Zfp105:β‐galactosidase (LacZ) knock‐in reporter mouse line (Zfp105LacZ/+) in which a Zfp105:LacZ fusion gene was expressed. Whole‐mount LacZ analyses of adult Zfp105LacZ/+ tissues showed robust LacZ staining in the testis, very weak staining in the ovary, and no staining in the spleen, liver, kidney, heart, lung, thymus, adrenal gland, uterus, or oviduct. Sectional LacZ staining showed that ZFP105 was highly expressed in pachytene spermatocytes. ZNF35, the human ortholog of Zfp105, was also highly expressed in human testis. Immunofluorescence analysis showed that ZNF35 was located primarily in the cytoplasm of male germ cells. More importantly, reduced male fertility was observed in adult Zfp105LacZ/LacZ mice. Histological studies showed the presence of undifferentiated spermatogenic cells in the lumen of seminiferous tubules at stage VII and in the epididymal lumen of adult Zfp105LacZ/LacZ mice. Taken together, our results suggest that ZFP105 is a male germ‐cell factor and plays a role in male reproduction. Mol. Reprod. Dev. 77: 511–520, 2010. © 2010 Wiley‐Liss, Inc.
Estimation of survival rate and extinction probability for stage‐structured populations with overlapping life stages
Authors: Aubry Aurélie , Bécart Emeline , Davenport John , Emmerson Mark Charles
Published: February 2010

The development of methods providing reliable estimates of demographic parameters (e.g., survival rates, fecundity) for wild populations is essential to better understand the ecology and conservation requirements of individual species. A number of methods exist for estimating the demographics of stage‐structured populations, but inherent mathematical complexity often limits their uptake by conservation practitioners. Estimating survival rates for pond‐breeding amphibians is further complicated by their complex migratory and reproductive behaviours, often resulting in nonobservable states and successive cohorts of eggs and tadpoles. Here we used comprehensive data on 11 distinct breeding toad populations (Bufo calamita) to clarify and assess the suitability of a relatively simple method [the Kiritani–Nakasuji–Manly (KNM) method] to estimate the survival rates of stage‐structured populations with overlapping life stages. The study shows that the KNM method is robust and provides realistic estimates of amphibian egg and larval survival rates for species in which breeding can occur as a single pulse or over a period of several weeks. The study also provides estimates of fecundity for seven distinct toad populations and indicates that it is essential to use reliable estimates of fecundity to limit the risk of under‐ or overestimating the survival rates when using the KNM method. Survival and fecundity rates for B. calamita populations were then used to define population matrices and make a limited exploration of their growth and viability. The findings of the study recently led to the implementation of practical conservation measures at the sites where populations were most vulnerable to extinction.
Piracy at Sea: Somalia an Area of Great Concern
Authors: Baniela Santiago Iglesias
Published: February 2010

In this paper, the author analyses piracy at sea in Somalia, to provide a general up-to-date vision of the problem which threatens the security of ships sailing in the Gulf of Aden. The pirates' modus operandi, the existing factors behind these punishable acts and the prevailing international response are analysed. Finally the paper reviews how the international community could act in order to tackle the problem with a view to its possible eradication.
Nature Inspired Target Reacquisition Strategies for Autonomous Vehicles in a Search Role
Authors: Banks Alec , Vincent Jonathan
Published: February 2010

Previous research by the authors has investigated the application of nature inspired search strategies and particle swarm optimisation to the guidance of autonomous vehicles in search roles. Findings suggest that nature inspired search strategies are beneficial under a wide range of search conditions. However, that research did not consider the potential for reacquisition of lost targets, which is especially of interest where the targets are travelling faster than the searching agents or in environments that allow for some means of visual or other sensory occlusion. This work investigates whether behaviours observed in nature can be applied to scenarios where target detection is lost. Through employing a variety of reacquisition strategies against a range of target movement types it is demonstrated that the overall effectiveness of the system can be improved in a variety of scenarios by incorporating nature inspired reacquisition strategies.
Introduction
Authors: Roberts George
Published: February 2010

The beautiful valley of the Axe lies in south-east Devonshire, about four miles west of Dorset. The red marl and brown and sterile summits of the green sand-hills mark the situation with unmistakable signs. A real Devonshire valley cannot be confounded with any other; nor can its climate. Mild in winter, when southern Italy has frost and snow, and when Greece is not to be traversed from the same causes, its curative influence at length begins to be appreciated.
Transient growth without inertia
Authors: Jovanović Mihailo R. , Kumar Satish
Published: February 2010

We study transient growth in inertialess plane Couette and Poiseuille flows of viscoelastic fluids. For streamwise-constant three-dimensional fluctuations, we demonstrate analytically the existence of initial conditions that lead to quadratic scaling of both the kinetic energy density and the elastic energy with the Weissenberg number, We. This shows that in strongly elastic channel flows of viscoelastic fluids, both velocity and polymer stress fluctuations can exhibit significant transient growth even in the absence of inertia. Our analysis identifies the spatial structure of the initial conditions (i.e., components of the polymer stress tensor at t=0) responsible for this large transient growth. Furthermore, we show that the fluctuations in streamwise velocity and the streamwise component of the polymer stress tensor achieve O(We) and O(We2) growth, respectively, over a time scale O(We) before eventual asymptotic decay. We also demonstrate that the large transient responses originate from the stretching of polymer stress fluctuations by a background shear and draw parallels between streamwise-constant inertial flows of Newtonian fluids and streamwise-constant creeping flows of viscoelastic fluids. One of the main messages of this paper is that at the level of velocity fluctuation dynamics, polymer stretching and the Weissenberg number in elasticity-dominated flows of viscoelastic fluids effectively assume the role of vortex tilting and the Reynolds number in inertia-dominated flows of Newtonian fluids.
Magnetic properties of multiferroic K3Cr2Fe3F15
Authors: Blinc R. , Cevc P. , Potočnik A. , Žemva B. , Goreshnik E. , Hanžel D. , Gregorovič A. , Trontelj Z. , Jagličič Z. , Laguta V. , Perović M. , Dalal N. S. , Scott J. F.
Published: February 2010

The local electronic and structural as well as the macroscopic magnetic properties of K3Cr2Fe3F15 have been studied between room temperature and 4 K. The system has been found to be isostructural with ferroelectric and weakly ferrimagnetic K3Fe5F15 above the ferroelectric transition temperature Tc. The X-band and 216 GHz Cr3+ electron paramagnetic resonance (EPR) spectra as well as the magnetic susceptibility and Mössbauer data show the existence of two magnetic relaxor type transitions around 37 and 17 K. The K39 magic angle sample spinning NMR, EPR, and the Mössbauer data further demonstrate the existence of two nonequivalent Fe, Cr, and K sites in the unit cell as well as the presence of rapid exchange at higher temperatures. The observation of the Fe2+ EPR and Mössbauer spectra shows that the Fe2+ ion is in a high spin state.
Response to “Comment on ‘Primary instability mechanisms on the magnetohydrodynamic boundary layer flow over a rotating disk subject to a uniform radial flow’” [Phys. Fluids 22, 029102 (2010)]
Authors: Turkyilmazoglu M.
Published: February 2010

It was pointed out by Thess [‘‘Comment on ‘Oblique axisymmetric stagnation flows in magnetohydrodynamics [Phys. Fluids 19, 114106 (2007)]’,’’ Phys. Fluids 20, 069102 (2008)] by Amaouche that the model used in the paper “Primary instability mechanisms on the magnetohydrodynamic boundary layer flow over a rotating disk subject to a uniform radial flow” by Turkyilmazoglu [Phys. Fluids 21, 074103 (2009)] is incomplete since the electric potential was neglected. This point is clarified here, and the ambiguity present in the magnetohydrodynamic flow research of this kind among the fluid dynamic community is remedied. As a consequence, the qualitative validity of the results in the work of Turkyilmazoglu [“Primary instability mechanisms on the magnetohydrodynamic boundary layer flow over a rotating disk subject to a uniform radial flow,” Phys. Fluids 21, 074103 (2009)] from both the physical and mathematical viewpoints is justified.
Scalable growth of free-standing graphene wafers with copper(Cu) catalyst on SiO2/Si substrate: Thermal conductivity of the wafers
Authors: Lee Yun-Hi , Lee Jong-Hee
Published: February 2010

The authors report scalable growth of free-standing graphene wafers with copper(Cu) catalyst on SiO2/Si substrate at low temperature and investigation of their thermal conductivity. The Cu is the most common and the cheapest catalyst among electronic materials. Our process for producing the graphene with the Cu is based on a low-pressure, fast-heating chemical vapor deposition method. Thermal conductivity measurements with nondestructive Raman spectroscopy showed that the free-standing-graphene is a good thermal conductor. The possibility of growing graphene wafer at low temperatures by using a Cu thin film should accelerate research and facilitate the development of graphene for practical applications
A high-reflectivity atom-focusing mirror stable at room temperature
Authors: Barredo D. , Laurent G. , Calleja F. , Nieto P. , Hinarejos J. J. , Vázquez de Parga A. L. , Farías D. , Miranda R.
Published: February 2010

It is shown that the Pb(√3×√3)R30/Si(111) ordered layer is an excellent mirror for neutral He atoms. It focuses more than 15% of the incoming He atoms into the specular peak, and is stable up to 450 K. Moreover, the reflectivity remains almost unchanged in a time scale of several weeks in ultrahigh vacuum. As a consequence, this system is a very good candidate to be used as a mirror in the next generation of the scanning helium atom microscope.
Reassortment between avian H5N1 and human H3N2 influenza viruses creates hybrid viruses with substantial virulence
Authors: Li Chengjun , Hatta Masato , Nidom Chairul A. , Muramoto Yukiko , Watanabe Shinji , Neumann Gabriele , Kawaoka Yoshihiro
Published: February 2010

The spread of avian H5N1 influenza viruses around the globe has become a worldwide public health concern. To evaluate the pathogenic potential of reassortant viruses between currently cocirculating avian H5N1 and human H3N2 influenza viruses, we generated all the 254 combinations of reassortant viruses between A/chicken/South Kalimantan/UT6028/06 (SK06, H5N1) and A/Tokyo/Ut-Sk-1/07 (Tok07, H3N2) influenza viruses by reverse genetics. We found that the presence of Tok07 PB2 protein in the ribonucleoprotein (RNP) complex allowed efficient viral RNA transcription in a minigenome assay and that RNP activity played an essential role in the viability and replicative ability of the reassortant viruses. When the pathogenicity of 75 reassortant H5 viruses was tested in mice, 22 were more pathogenic than the parental SK06 virus, and three were extremely virulent. Strikingly, all 22 of these viruses obtained their
PB2
segment from Tok07 virus. Further analysis showed that Tok07
PB1
alone lacked the ability to enhance the pathogenicity of the reassortant viruses but could do so by cooperating with Tok07
PB2
. Our data demonstrate that reassortment between an avian H5N1 virus with low pathogenicity in mice and a human virus could result in highly pathogenic viruses and that the human virus
PB2
segment functions in the background of an avian H5N1 virus, enhancing its virulence. Our findings highlight the importance of surveillance programs to monitor the emergence of human H5 reassortant viruses, especially those containing a
PB2
segment of human origin.
SBRML: a markup language for associating systems biology data with models
Authors: Dada Joseph O. , Spasić Irena , Paton Norman W. , Mendes Pedro
Published: February 2010

Motivation: Research in systems biology is carried out through a combination of experiments and models. Several data standards have been adopted for representing models (Systems Biology Markup Language) and various types of relevant experimental data (such as FuGE and those of the Proteomics Standards Initiative). However, until now, there has been no standard way to associate a model and its entities to the corresponding datasets, or vice versa. Such a standard would provide a means to represent computational simulation results as well as to frame experimental data in the context of a particular model. Target applications include model-driven data analysis, parameter estimation, and sharing and archiving model simulations.

Results: We propose the Systems Biology Results Markup Language (SBRML), an XML-based language that associates a model with several datasets. Each dataset is represented as a series of values associated with model variables, and their corresponding parameter values. SBRML provides a flexible way of indexing the results to model parameter values, which supports both spreadsheet-like data and multidimensional data cubes. We present and discuss several examples of SBRML usage in applications such as enzyme kinetics, microarray gene expression and various types of simulation results.

Availability and Implementation: The XML Schema file for SBRML is available at http://www.comp-sys-bio.org/SBRML under the Academic Free License (AFL) v3.0.

Contact:  pedro.mendes@manchester.ac.uk

Supplementary information:  Supplementary data are available at Bioinformatics online.
The influence of abiotic factors on gillnet catch rates of yellow perch in southern Lake Michigan, 1989–2006
Authors: RYDELL J. J. , LAUER T. E. , FORSYTHE P. S.
Published: February 2010

Abstract  The difference in yellow perch, Perca flavescens (Mitchill), catch rates were evaluated for gillnets set on the bottom at 10‐ and 15‐m depths in southern Lake Michigan during June, July and August from 1989 to 2006. More yellow perch were captured in gillnets set at 10 m than at 15 m. Differences in water temperature were significant in explaining variation in catch rates, but differences in Secchi depth and wave height were not significant. These results suggest that yellow perch may associate with habitat based on water temperature during the summer and move in response to thermal changes. In addition, this portion of the lake lacks noticeable heterogeneous structural habitat features that normally influence yellow perch behaviour. Fisheries managers should consider sampling based on temperature in addition to depth or other habitat features when designing sampling protocols.
Anterior development in the parthenogenetic and viviparous form of the pea aphid, Acyrthosiphon pisum: hunchback and orthodenticle expression
Authors: Huang T.‐Y. , Cook C. E. , Davis G. K. , Shigenobu S. , Chen R. P.‐Y. , Chang C.‐C.
Published: February 2010

In the dipteran Drosophila, the genes bicoid and hunchback work synergistically to pattern the anterior blastoderm during embryogenesis. bicoid, however, appears to be an innovation of the higher Diptera. Hence, in some non‐dipteran insects, anterior specification instead relies on a synergistic interaction between maternally transcribed hunchback and orthodenticle. Here we describe how orthologues of hunchback and orthodenticle are expressed during oogenesis and embryogenesis in the parthenogenetic and viviparous form of the pea aphid, Acyrthosiphon pisum. A. pisum hunchback (Aphb) mRNA is localized to the anterior pole in developing oocytes and early embryos prior to blastoderm formation – a pattern strongly reminiscent of bicoid localization in Drosophila. A. pisum orthodenticle (Apotd), on the other hand, is not expressed prior to gastrulation, suggesting that it is the asymmetric localization of Aphb, rather than synergy between Aphb and Apotd, that regulates anterior specification in asexual pea aphids.
Changes in specific domains of sexual function and sexual bother after radical prostatectomy
Authors: Le Jesse D. , Cooperberg Matthew R. , Sadetsky Natalia , Hittelman Adam B. , Meng Maxwell V. , Cowan Janet E. , Latini David M. , Carroll Peter R.
Published: February 2010

Study Type – Therapy (outcomes research) Level of Evidence 2c

OBJECTIVE

To quantitatively assess the effect of radical prostatectomy (RP) on the specific domains that comprise overall sexual function (SF), focusing on the relationships among these domains and overall SF, and to identify predictors for recovery of SF over time, as a decline in SF and sexual bother (SB) are known potential complications of treatment for prostate cancer.

PATIENTS AND METHODS

Within the Cancer of the Prostate Strategic Urologic Research Endeavor database, we identified men diagnosed between 1995 and 2001 with localized prostate cancer treated with RP. SF and SB outcomes, measured using the University of California Los Angeles Prostate Cancer Index, were assessed at 6‐month intervals for 4 years after RP.

RESULTS

In all, 620 men met the study criteria; at 6 months after RP, overall and all the specific domains of SF declined, with improvement in most specific domains by 2 years after RP. The greatest declines were in the ability to achieve erections, high‐quality erections, and frequent erections; these domains were also most strongly correlated with overall SF. Sexual desire was relatively preserved, and there was a weak correlation between overall SF and sexual desire after RP, when there was the greatest discrepancy between sexual desire and other domains of function. SB showed continued improvement over time to 4 years but was not well correlated with any measurements of SF assessed. Younger age, college education, sexual aid and medication use, the absence of comorbid conditions, and nerve‐sparing surgery were predictive of significant recovery of function in several specific domains of SF.

CONCLUSIONS

RP affects specific domains of SF to differing degrees. Compromised erectile function is most commonly reported among these specific domains and seems to play a more dominant role in determining overall SF, but notably none of the domains of function were closely linked to SB. Because education is protective in the perception of bother, appropriate counselling and the setting of expectations for outcomes in overall and specific domains of SF might lead to improved quality of life after treatment for prostate cancer.
SCIENCE AND SERIOUS THEOLOGY: TWO PATHS FOR SCIENCE AND RELIGION'S FUTURE?
Authors: Hallanger Nathan J.
Published: February 2010

Although they take different approaches, both Taede A. Smedes and Kevin Sharpe have challenged the theology‐and‐science enterprise and raised important questions about theological and scientific assumptions behind this work. Smedes argues that theology should be taken more seriously, and Sharpe believes that theology should be more scientific. A proposed middle way involves engaging in the dialogue itself and exploring the questions and methodological implications that arise in the context of problem‐focused interactions.
Attentional and neuromotor deficits in ADHD
Authors: Steger J , Imhof K , Lic E Coutts , Gundelfinger R , Steinhausen H‐Ch , Brandeis D
Published: February 2010

In order to classify attention‐deficit‐hyperactivity disorder (ADHD) in 11‐year‐old children, the role of specific attentional and motor deficits was examined. Participants comprised 22 children with ADHD (19 male, 3 female; median age 11 years, range 8.8 to 13.5 years) and 20 control children (17 male, 3 female; median age 10.6 years, range 8.2 to 12.6 years). Neuromotor assessment indicated that while both groups needed more time to complete finger compared to hand movements, this increase was more pronounced in children with ADHD. Reaction‐time testing with continuous‐force recording identified both motor and attentional deficits in children with ADHD. Longer intervals between force onset and force peak, and higher rate of responses with multiple force peaks (particularly in the bilateral condition) revealed specific deficits in the speed and quality of their motor output. Increase in errors and variability of force onsets indicated attentional deficits. Prediction analysis indicated that force‐onset variability contributed significantly to group classification which was 85.7% correct. Neither neuromotor assessment nor specific motor deficits contributed significantly to classification, indicating that pure motor‐speed measures play a minor role in characterizing ADHD in this age range.
The first articulated specimen of Plumulites canadensis (Woodward, 1889) from the Upper Ordovician of Ontario, with a review of the anterior region of Plumulitidae (Annelida: Machaeridia)
Authors: VINTHER JAKOB , RUDKIN DAVID
Published: February 2010

Abstract.  Articulated plumulitid machaeridians are rarely preserved intact. Here, we describe a complete specimen of Plumulites canadensis (Woodward, 1889) retaining much of the head region. The two anteriormost pairs of shell plates are quite distinct from the rest in outline, density of concentric rugae, and especially the radial ornamentation of the second pair. We demonstrate that the latter condition is present in other complete plumulitids and therefore widespread, which elucidates a larger diversity in morphology of plumulitids than realized previously.
Good Citizens vs. Good Workers: Low‐Income Girls and Clashing Subjectivities in a Charter School
Authors: Roaf Mary
Published: February 2010

Abstract: The public school system has continued to promote inequalities along axes of class, race and gender. Yet contestation over the role and purpose of public schooling has yielded significant social protest as well as reforms that are unfolding in often contradictory and complex ways. One set of conflicting aims characterizing current education reform is clashing definitions of the “good” citizen versus “good worker.” While neoliberal tenets posit “good” citizens and workers as those who exercise responsible “individual” choices, education reform enabling the adoption of radical pedagogies stresses a model of citizenship calling for individual and collective critical awareness and activism while still trying to prepare students to access further educational and employment opportunities as “good” workers. I explore how low‐income, female, predominantly African‐American high‐school students who attend a charter school incorporating a radical education pedagogy interpret, internalize, and contest these competing definitions of good citizens versus good workers.
Retracted: HYDRO‐SORTING OF APPLE USING TERMINAL VELOCITY IN WATER
Authors: KHEIRALIPOUR KAMRAN , TABATABAEEFAR AHMAD , MOBLI HOSSEIN , RAFIEE SHAHIN , RAJABIPOUR ALI , JAFARI ALI
Published: February 2010

Retracted: The following article from Journal of Food Process Engineering, “Hydro‐sorting of Apple Using Terminal Velocity in Water” by Kamran Kheiralipour, Ahmad Tabatabaeefar, Hossein Mobli, Shahin Rafiee, Ali Rajabipour, and Ali Jafari published online on 22 February 2010 in Wiley Online Library (http://www.onlinelibrary.wiley.com), has been retracted by agreement between the authors, the Journal's Co‐Editors, M. Elena Castell‐Perez and Rosana Moreira, and Wiley Periodicals, Inc. The retraction has been agreed due to overlap between this article and the following article published in the Transactions of the American Society of Agricultural Engineers (now called Transactions of the American Society of Agricultural and Biological Engineers), “Sorting of Kiwifruit for Quality Using Drop Velocity in Water” by Robert B. Jordan and Christopher J. Clark. Vol. 47:6 (2004): 1991–1998.
Effects of neuronal nitric oxide synthase inhibition on resting and exercising hindlimb muscle blood flow in the rat
Authors: Copp Steven W. , Hirai Daniel M. , Schwagerl Peter J. , Musch Timothy I. , Poole David C.
Published: February 2010

Nitric oxide (NO) derived from endothelial NO synthase (eNOS) is an integral mediator of vascular control during muscle contractions. However, it is not known whether neuronal NOS (nNOS)‐derived NO regulates tissue hyperaemia in healthy subjects, particularly during exercise. We tested the hypothesis that selective nNOS inhibition would reduce blood flow and vascular conductance (VC) in rat hindlimb locomotor muscle(s), kidneys and splanchnic organs at rest and during dynamic treadmill exercise (20 m min−1, 10% grade). Nineteen male Sprague–Dawley rats (555 ± 23 g) were assigned to either rest (n= 9) or exercise (n= 10) groups. Blood flow and VC were determined via radiolabelled microspheres before and after the intra‐arterial administration of the selective nNOS inhibitor S‐methyl‐l‐thiocitrulline (SMTC, 2.1 ± 0.1 μmol kg−1). Total hindlimb muscle blood flow (control: 20 ± 2 ml min−1 100g−1, SMTC: 12 ± 2 ml min−1 100g−1, P < 0.05) and VC (control: 0.16 ± 0.02 ml min−1 100 g−1 mmHg−1, SMTC: 0.09 ± 0.01 ml min−1 100 g−1 mmHg−1, P < 0.05) were reduced substantially at rest. Moreover, the magnitude of the absolute reduction in blood flow and VC correlated (P < 0.05) with the proportion of oxidative muscle fibres found in the individual muscles or muscle parts of the hindlimb. During exercise, total hindlimb blood flow (control: 108 ± 7 ml min−1 100 g−1, SMTC: 105 ± 8 ml min−1 100 g−1) and VC (control: 0.77 ± 0.06 ml min−1 100g−1 mmHg−1; SMTC: 0.70 ± 0.05 ml min−1 100g−1 mmHg−1) were not different (P > 0.05) between control and SMTC conditions. SMTC reduced (P < 0.05) blood flow and VC at rest and during exercise in the kidneys, adrenals and liver. These results enhance our understanding of the role of NO‐mediated circulatory control by demonstrating that nNOS does not appear to subserve an obligatory role in the exercising muscle hyperaemic response in the rat.
Soft Tissue Fixation and Implant Development: Venture Capital
Authors: Norton Evan
Published: February 2010

This talk will discuss venture capital trends globally and specifically how these trends are impacting the orthopedic market. The discussion will include: a. Current areas of interest in the venture community — i. Spin, ii. Knee/Hip, iii. Extremities/Small Bone; b. Choosing a financial partner; c. How to approach venture firms — i. Stage focus and how it impacts the entrepreneur, ii. General investment criteria; d. Making the pitch — i. How to make contact, ii. Key content/format, iii. Who is going to read what?, iv. Preparing for success, v. Market size, vi. Team, vii. Cap table, viii. All about milestones; e. Alternative funding sources; f. The costs associated with other people’s money.
Soft Tissue Fixation and Implant Development: Marketing/Commercialization
Authors: Tighe John
Published: February 2010

Marketing, Sales, and Commercialization: Marketing and sales of orthopaedic medical devices are two of the most challenging and costly aspects of a successful commercial product launch. Many companies have developed an innovative product, filed for patents, passed through regulatory hurdles, and yet ultimately failed because of an inadequate marketing and sales plan. Invariably product launches cost more money and take longer to get off the ground than most companies forecast.
Effect of the Micro-Porous Layer-Gas Diffusion Layer Interface on Water Transport in Polymer Electrolyte Fuel Cells
Authors: Preston Joshua , Fu Richard , Zhang Xiaoyu , Pasaogullari Ugur
Published: February 2010

An investigation of the liquid water saturation across the cross-section of an operating polymer electrolyte fuel cell is performed to analyze the saturation discontinuity predicted by numerical models. Numerical models have predicted a discontinuity in the liquid water saturation at the interface of the micro-porous layer and the coarser macroporous region of the gas diffusion layer. High-resolution through plane neutron radiography is used to acquire the water content distribution across the thickness of the gas-diffusion layer and study the effects of the interface. The measured liquid water profiles indicate no obvious discontinuity in the liquid water saturation across the cross-section of the bi-layer gas diffusion layer when large areas are averaged spatially. Evidence of the discontinuity is found when small spatial averaging is used in certain locations. Other locations show no evidence of the discontinuity. Scanning electron microscopy is used to examine the microstructure of two types of the bi-layer diffusion media. The images show that the approximation of the interface as a sudden, distinct feature may not be appropriate. The results suggest that a model that considers the existence of an interfacial region in the diffusion media may be appropriate, in which the properties vary continuously.
A Finite Volume SOFC Model for Coal-Based Integrated Gasification Fuel Cell System Analysis
Authors: Li Mu , Brouwer Jacob , Powers James D. , Samuelsen G. Scott
Published: February 2010

Integrated gasification fuel cell (IGFC) systems combining coal gasification and solid oxide fuel cells (SOFC) are promising for highly efficient and environmentally friendly utilization of coal for energy production. Most IGFC system analyses performed to date have used non-dimensional thermodynamic SOFC models that do not resolve the intrinsic constraints of SOFC operation. In this work, a one-dimensional finite volume model for planar SOFC is developed and verified using literature data. Special attention is paid to making the model capable of supporting recent SOFC technology improvements, including the use of anode-supported configurations, metallic interconnects, and reduced polarization losses. Results are presented for SOFC operation on humidified hydrogen and methane-containing syngas, under co-flow and counter-flow configurations; detailed internal profiles of species mole fractions, temperature, current density and electrochemical performance are obtained. The effects of performance, fuel composition and flow configuration on SOFC performance and thermal profiles are evaluated, and the implications of these results for system design and analysis are discussed.
Compressor Fouling in Gas Turbines Offshore: Composition and Sources From Site Data
Authors: Brekke Olaf , Bakken Lars E. , Syverud Elisabet
Published: February 2010

Contamination in the intake air causes fouling in the compressor section of gas turbines. The amount and type of fouling present in the compressor section is site-specific, and knowledge of its composition is important in order to achieve efficient intake air filtration. This knowledge is also of great importance when optimizing both online and offline compressor wash regimes. This paper presents the results of an investigation of compressor fouling in two different offshore gas turbine installations. Fouling samples collected from various locations in the gas turbine air intakes, inlet guide vanes, and first compressor rotor stages were analyzed in a laboratory using an electron probe micron analyzer. The structure and composition of the analyzed compressor fouling is determined, and the probable sources of the different elements are identified.
Modelling of Buoyancy-Affected Flow in Co-Rotating Disc Cavities
Authors: Kilfoil Alistair S. R. , Chew John W.
Published: February 2010

Research in rotational buoyancy-driven flow has shown that the flow within the compressor inter-disc cavities is highly three-dimensional and time dependent. Two approaches in the numerical modelling of the flow have been considered. One is to use 3D, unsteady CFD to model a single inter-disc cavity with axial throughflow. This is very computationally expensive. A second approach, adopted here, is to break down the complex flow process into separate physical mechanisms and introduce approximate but computationally efficient models for these processes. The aim is to produce a method that can be incorporated into current design practice. Two underlying flow mechanisms may be identified for this complex flow; the first associated with the flow within the inter-disc cavities and the second associated with the axial throughflow under the compressor disc bores. Using CFD, the modelling of these two underlying flow mechanisms has been combined and a steady axisymmetric modelling method has been developed. The technique has been applied to both a research compressor rig and to an actual gas turbine HP compressor rotor, and results have been compared to measured data.
Air-Steam Gasification of Dairy Biomass Using Small Scale Fixed Bed Gasifier
Authors: Gordillo Gerardo , Annamalai Kalyan
Published: February 2010

The composition of gases obtained from gasification of biomass fuels depends principally upon parameters like fuel and oxidizing medium supplied, equivalence ratio (Φ), steam-fuel ratio (S:F), pressure, reaction temperature, and residence time in the gasifier. Gasification with steam only is an endothermic process which produces rich mixtures of CO and H2 while gasification with air-steam may not require heat input in order to produce H2 rich mixtures of CO and CO2. Furthermore, gases produced by gasification with-air-steam can be supplied to a shift reactor to produce mixtures of H2, CO2, and N2. When pure O2 is used instead of air, the H2 separated from CO2 can be used for in situ sustainable green power generation. The gasification process can handle low quality fuel and larger sized particles. While coal has higher fixed carbon (FC) providing more heat for gasification, the Dairy biomass (DB) selected in current study has lower FC and hence contributes less heat. While most of the past studies deal with gasification of coal, current study concentrates on DB as fuel. Experimental results are presented for gasification of i) dairy biomass (DB) and ii) DB ash blends (DBAB) using a 10 KW fixed bed counter-flow gasifier and air-steam as oxidizing source. The results show that the reactor operates almost adiabatically. The effects of the Φ and S:F ratio on peak temperatures, gas composition, gross heating value of the products (HHV), and energy conversion efficiency (ECE) are investigated. A mass spectrometer has been used to analyze the composition of gases in real time continuously. Increasing Φ or S:F increases the production of H2 and CO2 but decreases the production of CO; thus, the reaction of CO+H2O→CO2+H2 seems to control the composition of gases. The operating parameters include 1.59<Φ<6.36 and 0.36<S:F<0.8. Energy Conversion efficiencies (ECE) range from 0.26 to 0.80.
On the Adequacy of Chemiluminescence as a Measure for Heat Release in Turbulent Flames With Mixture Gradients
Authors: Lauer Martin , Sattelmayer Thomas
Published: February 2010

The determination of the heat release in technical flames is commonly done via bandpass filtered chemiluminescence measurements in the wavelength range of OH* or CH* radicals, which are supposed to be a measure for the heat release rate. However, these indirect heat release measurements are problematic, because the measured intensities are the superposition of the desired radical emissions and contributions from the broadband emissions of CO2*. Furthermore, the chemiluminescence intensities are strongly affected by the local air excess ratio of the flame and the turbulence intensity in the reaction zone. To investigate the influence of these effects on the applicability of chemiluminescence as a measure for heat release rate in turbulent flames with mixture gradients, a reference method is used, which is based on the first law of thermodynamics. It is shown that although the integral heat release can be correlated with the integral chemiluminescence intensities, the heat release distribution is not properly represented by any signal from OH* or CH*. No reliable information about the spatially resolved heat release can be obtained from chemiluminescence measurements in flames with mixture gradients.
Weak Extinction in Low NOx Gas Turbine Combustion
Authors: Andrews Gordon E. , Ahmed N. T. , Phylaktou Roth , King Phil
Published: February 2010

Well mixed low NOx gas turbines are limited, in the operational range of the low NOx mode, by the weak extinction and CO limits of the flame stabiliser used. The operational range of the combustor in the <10ppm low NOx mode is set by the range of equivalence ratios over which ultra low NOx without acoustic resonance can be achieved. This paper reviews the available data on weak extinction in well mixed low NOx combustion systems and presents some new data. Atmospheric pressure weak extinction data is shown to be similar to weak extinction at pressure for similar stabiliser designs and reference velocities. For low NOx gas turbine combustion it is demonstrated that all the best weak extinctions are identical to the lean flammability limit for laminar flames. Weak extinction is where the flow velocity exceeds the turbulent burning velocity and data on weak extinction is used as a measure of the mean turbulent burning velocity and shown to correlate with turbulent burning velocity data and theories. Methods of predicting the peak turbulence generated downstream of a flame stabiliser are outlined, based on grid plate measurements of turbulence and pressure loss. It is shown that a wide range of premixed flame stabilisers including swirling and non-swirling flame stabilisers have a weak extinction that can be predicted using this method.
ATF Test Evaluation of Model Based Control for a Single Spool Turbojet Engine
Authors: Tagashira Takeshi , Mizuno Takuya , Koh Masaharu , Sugiyama Nanahisa
Published: February 2010

This paper introduces a model based control system for a single spool turbojet engine. It consists of a feedback control (FBC) and a component level model (CLM) enhanced by the Constant Gain Extended Kalman Filter (CGEKF). The control system is implemented on a rugged PC, and verified to run in much faster than real time, which is essential requirement for a model based control. Then, the model based control system developed is applied to an actual engine and evaluation test is conducted by using an Altitude Test Facility (ATF). Several types of model based feedback controls are evaluated under various flight conditions, giving intentional engine performance change by varying nozzle area, and intentional sensor failure. It is concluded that the model based control using CGEKF is stable and shows good control performances over the whole flight envelope.
Gas Bearing Technology for Oil-Free Microturbomachinery: Research Experience for Undergraduate (REU) Program at Texas A&M University
Authors: San Andre´s Luis , Kim Tae Ho , Ryu Keun , Chirathadam Thomas A. , Hagen Kathleen , Martinez Alejandro , Rice Brian , Niedbalski Nick , Hung Wayne , Johnson Michael
Published: February 2010

The education of undergraduate mechanical engineering students (UGME) in state of the art technology development for microturbomachinery (MTM) is of importance to ensure the availability of qualified labor satisfying MTM manufacturer and end used needs, as well as to encourage the students towards pursing advanced degrees in science and engineering. National Science Foundation (NSF) funds a three-year summer Research Experience for Undergraduates (REU) Program (#0552885) to conduct hands-on training and research in mechanical, manufacturing, industrial, or materials engineering topics related to technological advances in microturbomachinery. The paper details the progress in research achieved by four UG students during 10 weeks in the summer of 2008. The students, assisted by seasoned graduate students and expert faculty, conducted work in aspects of gas bearing technology from manufacturing bearing components, to conducting rotordynamic performance tests, and to predicting rotordynamics performance. During the program, the students attended to a number of technical seminars including vocational and counseling presentations and preparation for admission to graduate school. The paper showcases the students’ technical posters produced upon completion of their 10 week research program: (1) Precision Tooling for Manufacturing an Underspring of a Generation II Foil Bearing, (2) Measurements of Imbalance Response of a Rotor Supported on Gas Foil Bearings, (3) Predictions of Nonlinear Rotordynamics of Rotor-Foil Bearing Systems, and (4) Measurements of Rotor Lift-Off and Break Up Torque in a Metal Mesh Foil Bearing. NASA GRC and Honeywell Turbocharging Technologies also provided support that enabled the success of the NSF REU program. URL http://reumicro.tamu.edu provides full descriptions on the program, topics of study, faculty involved and participating students.
Development of Condition Monitoring Test Cell Using Micro Gas Turbine Engine
Authors: Kho Seonghee , Ki Jayoung , Park Miyoung , Kong Changduk , Lee Kyungjae
Published: February 2010

This study is aim to be programmed the simulation which is available for real-time performance analysis so that is to be developed gas turbine engine’s condition monitoring system with analyzing difference between performance analysis results and measuring data from test cell. In addition, test cell created by this study have been developed to use following applications: to use for learning principals and mechanism of gas turbine engine in school, and to use performance test and its further research for variable operating conditions in associated institutes. The maximum thrust of the micro turbojet engine is 137 N (14 kgf) at 126,000 rpm of rotor rotational speed if the Jet A1 kerosene fuel is used. The air flow rate is measured by the inflow air speed of duct, and the fuel flow is measured by a volumetric fuel flowmeter. Temperatures and pressures are measured at the atmosphere, the compressor inlet and outlet and the turbine outlet. The thrust stand was designed and manufactured to measure accurately the thrust by the load cell. All measuring sensors are connected to a DAQ (Data Acquisition) device, and the logging data are used as function parameters of the program, LabVIEW. The LabVIEW is used to develop the engine condition monitoring program. The proposed program can perform both the reference engine model performance analysis at an input condition and the real-time performance analysis with real-time variables. By comparing two analysis results the engine condition can be monitored. Both engine performance analysis data and monitoring results are displayed by the GUI (Graphic User Interface) platform.
Experimental Analysis of a Waveguide Pressure Measuring System
Authors: White Matthew A. , Dhingra Manuj , Prasad J. V. R.
Published: February 2010

An infinite line probe is commonly used to measure unsteady pressure in high temperature environments while protecting the pressure transducer. In this study, an existing theoretical model is used to derive the response of a waveguide pressure measuring system. An ambient temperature centrifugal compressor rig acts as an experimental source of fluctuating pressure. The compressor is operated at different discrete rotational speeds, and the blade passing frequencies are used to obtain frequency response data. In the experiments, pressure waves attenuated at a rate faster than that predicted by the theoretical model for a 0.322 m (12 in) sensor offset. Further, the decay in the magnitude of the pressure oscillations accelerated at blade passing frequencies above 9 kHz. A unique contribution of this study is to show that whereas the experimentally observed overall attenuation is broadly consistent with the theoretical predictions, pressure oscillations corresponding to individual blade passages may be disproportionally attenuated.
Tomography-Based Heat and Mass Transfer Characterization of Reticulate Porous Ceramics for High-Temperature Processing
Authors: Haussener Sophia , Coray Patrick , Lipin´ski Wojciech , Wyss Peter , Steinfeld Aldo
Published: February 2010

Reticulate porous ceramics employed in high-temperature processes are characterized for heat and mass transfer. The exact 3D digital geometry of their complex porous structure is obtained by computer tomography and used in direct pore-level simulations to numerically calculate their effective transport properties. Two-point correlation functions and mathematical morphology operations are applied for the geometrical characterization that includes the determination of porosity, specific surface area, representative elementary volume edge size, and mean pore size. Finite volume techniques are applied for conductive/convective heat transfer and flow characterization that includes the determination of the thermal conductivity, interfacial heat transfer coefficient, permeability, Dupuit-Forchheimer coefficient, residence time, tortuosity, and diffusion tensor. Collision-based Monte Carlo method is applied for the radiative heat transfer characterization that includes the determination of the extinction coefficient and scattering phase function.
An Efficient Wavy Microchannel Heat Sink for Electronic Devices
Authors: Sui Y. , Teo C. J. , Lee P. S. , Chew Y. T. , Shu C.
Published: February 2010

In this paper, we have designed a compact and efficient liquid-cooled heat sink for mini-sized electronic devices, particularly for very-large-scale integrated (VLSI) circuits. The heat sink can either be an integral part of the silicon (or metal) substrate, or a separate part attached onto the substrate. The heat sink consists of several wavy microchannels, with hydraulic diameter on the order of 100 μm, microfabricated on a silicon or metal substrate. The fluid flow and heat transfer performance of the heat sink are studied using numerical simulations in the steady laminar flow region and the dynamical system technique using Poincare´ sections is employed to analyze the fluid mixing. It is found that when the liquid coolant flows through the wavy microchannel, Dean vortices can develop. The quantity and location of the Dean vortices may change along the flow direction, which can lead to laminar chaos. The chaotic advection greatly enhances the fluid mixing, and thus the heat transfer performance of the present heat sink is much more superior than previous designs which employed straight microchannels. It is also found that the pressure drop penalty is much smaller that the heat transfer enhancement for the present heat sink. Furthermore, the relative wavy amplitude (wavy amplitude/wavelength) of the channels can be varied along the flow direction for various purposes, without compromising the compactness and efficiency of the heat sink. The relative waviness can be increased along the flow direction, which results in higher heat transfer coefficients and renders the temperature for the devices much more uniform. The relative waviness can also be designed to be higher in regions of high heat flux for hot spot mitigation purposes.