bluuebunny/crossref_metadata_2025 huggingface dataset:
Drug‐induced hepatotoxicity: incidence of abnormal liver function tests consistent with volatile anaesthetic hepatitis in trauma patients
Authors: Lin Jonathan , Moore David , Hockey Brad , Di Lernia Rachel , Gorelik Alexandra , Liew Danny , Nicoll Amanda
Published: July 2013

Background & Aims

Volatile anaesthetic drug‐induced liver injury can range from asymptomatic alanine transaminase elevations to fatal hepatic necrosis. There is very limited research regarding hepatotoxicity of modern volatile anaesthetic agents. The aim of this study was to determine how common liver injury consistent with volatile anaesthetic hepatitis is, following exposure to isoflurane, desflurane and sevoflurane; and to propose risk factors for its development.

Methods

Following ethics approval, we conducted a retrospective audit of adult trauma patients with abnormal liver biochemistry following volatile anaesthesia during January 1 to December 31, 2009. The data collected included patient demographics, volatile anaesthetic administration, concurrent medication, perioperative liver biochemistry results and comorbidities. The Council for International Organisations of Medical Sciences/Roussel Uclaf Causality Assessment Method scoring system was used to group cases according to the likelihood of volatile anaesthetic being the causative agent of drug‐induced hepatotoxicity.

Results

Forty‐seven (3%) of 1556 patients had abnormal post‐operative liver biochemistry potentially attributable to volatile anaesthetic. Of the 47, 12 patients (26%) had peak alanine transaminase levels greater than 200 U/L. No significant predictors of volatile anaesthetic drug‐induced liver injury following isoflurane, desflurane or sevoflurane anaesthesia could be identified.

Conclusion

Volatile anaesthetic drug‐induced liver injury in adult trauma patients may be significantly more common than previously noted. This study suggests that about a quarter of patients with volatile anaesthetic drug‐induced liver injury develop significant liver injury. Further prospective studies are required to define risk factors and clinical outcomes.
MHC‐disassortative mate choice and inbreeding avoidance in a solitary primate
Authors: Huchard Elise , Baniel Alice , Schliehe‐Diecks Susanne , Kappeler Peter M.
Published: July 2013

Sexual selection theory suggests that choice for partners carrying dissimilar genes at the major histocompatibility complex (MHC) may play a role in maintaining genetic variation in animal populations by limiting inbreeding or improving the immunity of future offspring. However, it is often difficult to establish whether the observed MHC dissimilarity among mates drives mate choice or represents a by‐product of inbreeding avoidance based on MHC‐independent cues. Here, we used 454‐sequencing and a 10‐year study of wild grey mouse lemurs (Microcebus murinus), small, solitary primates from western Madagascar, to compare the relative importance on the mate choice of two MHC class II genes, DRB and DQB, that are equally variable but display contrasting patterns of selection at the molecular level, with DRB under stronger diversifying selection. We further assessed the effect of the genetic relatedness and of the spatial distance among candidate mates on the detection of MHC‐dependent mate choice. Our results reveal inbreeding avoidance, along with disassortative mate choice at DRB, but not at DQB. DRB‐disassortative mate choice remains detectable after excluding all related dyads (characterized by a relatedness coefficient r > 0), but varies slightly with the spatial distance among candidate mates. These findings suggest that the observed deviations from random mate choice at MHC are driven by functionally important MHC genes (like DRB) rather than passively resulting from inbreeding avoidance and further emphasize the need for taking into account the spatial and genetic structure of the population in correlative tests of MHC‐dependent mate choice.
Phylogeography and postglacial recolonization of Europe by Rhinolophus hipposideros: evidence from multiple genetic markers
Authors: Dool Serena E. , Puechmaille Sébastien J. , Dietz Christian , Juste Javier , Ibáñez Carlos , Hulva Pavel , Roué Stéphane G. , Petit Eric J. , Jones Gareth , Russo Danilo , Toffoli Roberto , Viglino Andrea , Martinoli Adriano , Rossiter Stephen J. , Teeling Emma C.
Published: July 2013

The demographic history of Rhinolophus hipposideros (lesser horseshoe bat) was reconstructed across its European, North African and Middle‐Eastern distribution prior to, during and following the most recent glaciations by generating and analysing a multimarker data set. This data set consisted of an X‐linked nuclear intron (Bgn; 543 bp), mitochondrial DNA (cytb‐tRNA‐control region; 1630 bp) and eight variable microsatellite loci for up to 373 individuals from 86 localities. Using this data set of diverse markers, it was possible to determine the species’ demography at three temporal stages. Nuclear intron data revealed early colonization into Europe from the east, which pre‐dates the Quaternary glaciations. The mtDNA data supported multiple glacial refugia across the Mediterranean, the largest of which were found in the Ibero‐Maghreb region and an eastern location (Anatolia/Middle East)–that were used by R. hipposideros during the most recent glacial cycles. Finally, microsatellites provided the most recent information on these species’ movements since the Last Glacial Maximum and suggested that lineages that had diverged into glacial refugia, such as in the Ibero‐Maghreb region, have remained isolated. These findings should be used to inform future conservation management strategies for R. hipposideros and show the power of using a multimarker data set for phylogeographic studies.
The Central Paradox of the New Digital Age
Authors: SCHMIDT ERIC , COHEN JARED
Published: July 2013

The recent scandal of the National Security Agency (NSA) “Hoovering” up the metadata on US and foreign citizens from Google, Facebook and Yahoo exposes in the full light of day the central paradox of the new digital age: The Internet enables us to know and learn more than ever before, but enables more to be known and learned about us by both snooping governments and monetizing information corporations alike.

In this section, Google's Eric Schmidt and Jared Cohen discuss this paradox. We also reprint an interview from 2009 with Mike McConnell, a former chief of the National Security Agency and the driving force behind Booz, Allen, Hamilton's digital security operation. Edward Snowden, the systems administrator who blew the whistle, was employed by the NSA as a subcontractor from Booz, Allen, Hamilton.
Educational attainment and obesity: a systematic review
Authors: Cohen A. K. , Rai M. , Rehkopf D. H. , Abrams B.
Published: July 2013

Although previous systematic reviews considered the relationship between socioeconomic status and obesity, almost 200 peer‐reviewed articles have been published since the last review on that topic, and this paper focuses specifically on education, which has different implications. The authors systematically review the peer‐reviewed literature from around the world considering the association between educational attainment and obesity. Databases from public health and medicine, education, psychology, economics, and other social sciences were searched, and articles published in English, French, Portuguese and Spanish were included. This paper includes 289 articles that report on 410 populations in 91 countries. The relationship between educational attainment and obesity was modified by both gender and the country's economic development level: an inverse association was more common in studies of higher‐income countries and a positive association was more common in lower‐income countries, with stronger social patterning among women. Relatively few studies reported on lower‐income countries, controlled for a comprehensive set of potential confounding variables and/or attempted to assess causality through the use of quasi‐experimental designs. Future research should address these gaps to understand if the relationship between educational attainment and obesity may be causal, thus supporting education policy as a tool for obesity prevention.
Melanomas of unknown primary have a mutation profile consistent with cutaneous sun‐exposed melanoma
Authors: Dutton‐Regester Ken , Kakavand Hojabr , Aoude Lauren G. , Stark Mitchell S. , Gartside Michael G. , Johansson Peter , O'Connor Linda , Lanagan Cathy , Tembe Varsha , Pupo Gulietta M. , Haydu Lauren E. , Schmidt Christopher W. , Mann Graham J. , Thompson John F. , Scolyer Richard A. , Hayward Nicholas K.
Published: July 2013

Melanoma of unknown primary (MUP) is an uncommon phenomenon whereby patients present with metastatic disease without an evident primary site. To determine their likely site of origin, we combined exome sequencing from 33 MUPs to assess the total rate of somatic mutations and degree of UV mutagenesis. An independent cohort of 91 archival MUPs was also screened for 46 hot spot mutations highly prevalent in melanoma including BRAF, NRAS, KIT, GNAQ, and GNA11. Results showed that the majority of MUPs exhibited high somatic mutation rates, high ratios of C>T/G>A transitions, and a high rate of BRAF (45 of 101, 45%) and NRAS (32 of 101, 32%) mutations, collectively indicating a mutation profile consistent with cutaneous sun‐exposed melanomas. These data suggest that a significant proportion of MUPs arise from regressed or unrecognized primary cutaneous melanomas or arise de novo in lymph nodes from nevus cells that have migrated from the skin.
From hospital to the community: The influence of deinstitutionalization on discharged long‐stay psychiatric patients
Authors: Kunitoh Namino
Published: July 2013

The aim of the present study is to clarify the influence of deinstitutionalization on discharged long‐stay patients based on a review of recently published literature. English‐language studies were searched from PubMed and Embase for the years 2000–2012, with the terms ‘long‐stay’ or ‘chronic mentally ill’ and ‘deinstitutionalis(z)ation’ or ‘community’ or ‘discharged’ in the title and/or abstract. The present study defined long‐stay as hospitalization >6 months. A total of 14 articles were identified. The majority of the participants suffered from schizophrenia. The most frequently assessed outcomes were social functioning, psychiatric symptoms and quality of life (QOL)/participant attitudes towards the environment. For social functioning, most of the studies found favorable changes. As regards psychiatric symptoms, stability or at least some improvements were detected. For QOL/participant attitudes towards the environment, positive changes, at least at some time‐points, were noted. Significant deterioration was rare in all of the three outcomes. The majority of the participants showed enhancements in social functioning despite the fact that functional impairment is common in persons with schizophrenia, which indicates that even long‐stay patients could achieve better functioning by deinstitutionalization. Although the stability in symptoms might be due to continuous schizophrenia course, moving to the community may also lead to improvement. The favorable changes in QOL/participants’ attitudes towards the environment are in line with other studies.
Bioactivity of natural O‐prenylated phenylpropenes from Illicium anisatum leaves and their derivatives against spider mites and fungal pathogens
Authors: Koeduka T. , Sugimoto K. , Watanabe B. , Someya N. , Kawanishi D. , Gotoh T. , Ozawa R. , Takabayashi J. , Matsui K. , Hiratake J.
Published: July 2013

A variety of volatile phenylpropenes, C6‐C3 compounds are widely distributed in the plant kingdom, whereas prenylated phenylpropenes are limited to a few plant species. In this study, we analysed the volatile profiles from Illicium anisatum leaves and identified two O‐prenylated phenylpropenes, 4‐allyl‐2‐methoxy‐1‐[(3‐methylbut‐2‐en‐1‐yl)oxy]benzene [O‐dimethylallyleugenol (9)] and 5‐allyl‐1,3‐dimethoxy‐2‐(3‐methylbut‐2‐en‐1‐yl)oxy]benzene [O‐dimethylallyl‐6‐methoxyeugenol (11)] as major constituents. The structure–activity relationship of a series of eugenol derivatives showed that specific phenylpropenes, including eugenol (1), isoeugenol (2) and 6‐methoxyeugenol (6), with a phenolic hydroxy group had antifungal activity for a fungal pathogen, whereas guaiacol, a simple phenolic compound, and allylbenzene had no such activity. The eugenol derivatives that exhibited antifungal activity, in turn, had no significant toxicant property for mite oviposition. Interestingly, O‐dimethylallyleugenol (9) in which the phenolic oxygen was masked with a dimethylallyl group exhibited a specific, potent oviposition deterrent activity for mites. The sharp contrast in structural requirements of phenylpropenes suggested distinct mechanisms underlying the two biological activities and the importance of a phenolic hydroxy group and its dimethylallylation for the structure‐based design of new functional properties of phenylpropenes.
Increased endocytosis of fluorescent phospholipid in tobacco pollen in microgravity and inhibition by verapamil
Authors: Scherer G. F. E. , Quader H.
Published: July 2013

Gravity sensing in plants occurs in specialised tissues, like in the columella in root tips or the endodermis in shoots. Generally, dense organelles, acting as statoliths, are thought to interact with the cytosekeleton and ion channels in gravitropism. We examined the possibility that tobacco pollen tubes (Nicotiana sylvestris) having an elaborate cytoskeleton could perceive gravity through interaction of the cytoskeleton and the endomembrane system and organelles. Using lipid endocytosis as a quantitative parameter, we show that endocytosis is increased transiently in microgravity within 3 min. This increase is inhibited by the calcium blocker verapamil, suggesting that calcium is lowered in the tip, which is known to increase endocytosis in the pollen tube.
Drought stress does not protect Quercus ilex L. from ozone effects: results from a comparative study of two subspecies differing in ozone sensitivity
Authors: Alonso R. , Elvira S. , González‐Fernández I. , Calvete H. , García‐Gómez H. , Bermejo V.
Published: July 2013

Long‐term effects of ozone (O3) exposure and drought stress were assessed on two subspecies of Quercus ilex: ssp. ilex and ssp. ballota. Two‐year‐old seedlings were continuously exposed for 26 months in open‐top chambers to three O3 treatments: charcoal filtered air, non‐filtered air and non‐filtered air supplemented with 40 nl·l−1 O3. Additionally, two irrigation regimes were adopted: half of the plants were well‐watered and the others received half of the water supplied to control plants. Growth, shoot water potential and gas exchange rates were assessed seasonally, and biomass accumulation was determined at the end of the experiment. Drought stress caused higher reductions of gas exchange, growth and biomass accumulation than O3 exposure in both subspecies. The combination of O3 and drought stress caused further decreases of accumulated aboveground biomass but no additive effects were observed on gas exchange rates or root biomass. Thus, drought stress did not protect Q. ilex from O3 effects on biomass when the response of the whole plant was considered. Q. ilex ssp. ballota was more sensitive to O3 and ssp. ilex was more affected by drought stress. The different O3 sensitivity was not only related to pollutant uptake but also to the ability of plants for resource acquisition and allocation. Based on biomass dose–response functions, Q. ilex is more resistant to O3 than other European evergreen tree species, however, O3 represents an additional stress factor that might be impairing plant ability to withstand current and future climate change.
Regulating finance after the crisis: Unveiling the different dynamics of the regulatory process
Authors: Moschella Manuela , Tsingou Eleni
Published: July 2013

It is now widely recognized that regulatory failures contributed to the onset of the global financial crisis. Redressing such failures has, thus, been a key policy priority in the post‐crisis reform agenda at both the domestic and international levels. This special issue investigates the process of post‐crisis financial regulatory reform in a number of crucial issue areas, including the rules and arrangements that govern financial supervision, offshore financial centers and shadow banking, the financial industry's involvement in global regulatory processes, and macroeconomic modeling. In so doing, the main purpose of this special issue is to shed light on an often understudied aspect in regulation literature: the variation in the dynamics of regulatory change. Contributors examine the different dynamics of regulatory change observed post‐crisis and explain variations by accounting for the interaction between institutional factors, on the one hand, and the activity of change agents and veto players involved in the regulatory reform process, on the other.
Eating behaviours in youths: A comparison between female and male athletes and non‐athletes
Authors: Fortes L. de S. , Kakeshita I. S. , Almeida S. S. , Gomes A. R. , Ferreira M. E. C.
Published: July 2013

This study compared the different factors associated with eating behaviors among young female and male athletes and non‐athletes. A total of 580 female and male athletes and 362 female and male non‐athletes between 10 and 19 years old participated. We used the subscales of the Eating Attitudes Test (EAT‐26) to evaluate the factors associated with unhealthy eating behaviors. We found higher scores for females on the diet subscale compared with males, regardless of athletic group (P < 0.05). Non‐athlete youths scored higher on this subscale compared with male athletes (P < 0.05). Our findings indicate higher scores for female athletes with regard to the bulimia and preoccupation with food subscale compared with other the groups (P < 0.05). Moreover, we observed that non‐athlete males were more likely to engage in binge eating compared with athletes of the same sex (P < 0.05). Finally, females had higher scores on the oral self subscale than males, regardless of athletic group (P < 0.05). We concluded that the factors associated with eating behaviors differ with regard to sex and group.
Barley whole exome capture: a tool for genomic research in the genus Hordeum and beyond
Authors: Mascher Martin , Richmond Todd A. , Gerhardt Daniel J. , Himmelbach Axel , Clissold Leah , Sampath Dharanya , Ayling Sarah , Steuernagel Burkhard , Pfeifer Matthias , D'Ascenzo Mark , Akhunov Eduard D. , Hedley Pete E. , Gonzales Ana M. , Morrell Peter L. , Kilian Benjamin , Blattner Frank R. , Scholz Uwe , Mayer Klaus F.X. , Flavell Andrew J. , Muehlbauer Gary J. , Waugh Robbie , Jeddeloh Jeffrey A. , Stein Nils
Published: July 2013

Advanced resources for genome‐assisted research in barley (Hordeum vulgare) including a whole‐genome shotgun assembly and an integrated physical map have recently become available. These have made possible studies that aim to assess genetic diversity or to isolate single genes by whole‐genome resequencing and in silico variant detection. However such an approach remains expensive given the 5 Gb size of the barley genome. Targeted sequencing of the mRNA‐coding exome reduces barley genomic complexity more than 50‐fold, thus dramatically reducing this heavy sequencing and analysis load. We have developed and employed an in‐solution hybridization‐based sequence capture platform to selectively enrich for a 61.6 megabase coding sequence target that includes predicted genes from the genome assembly of the cultivar Morex as well as publicly available full‐length cDNAs and de novo assembled RNA‐Seq consensus sequence contigs. The platform provides a highly specific capture with substantial and reproducible enrichment of targeted exons, both for cultivated barley and related species. We show that this exome capture platform provides a clear path towards a broader and deeper understanding of the natural variation residing in the mRNA‐coding part of the barley genome and will thus constitute a valuable resource for applications such as mapping‐by‐sequencing and genetic diversity analyzes.
Association between surgical resident involvement and blood use in noncardiac surgery
Authors: Glance Laurent G. , Mukamel Dana B. , Blumberg Neil , Fleming Fergal J. , Hohmann Samuel F. , Dick Andrew W.
Published: July 2013

Background

Although there is significant variability in the rate of blood transfusion in surgical patients, the role of surgical skill as a determinant of blood use is unknown.

Study Design and Methods

We examined the association between surgery resident participation and intraoperative blood transfusion, and 30‐day mortality and complications, among 381,036 patients undergoing noncardiac surgery, adjusting for patient factors and procedure complexity.

Results

Compared to attending surgeons working without a resident, cases in which the attendings worked with either Postgraduate Year (PGY) 3 to 4 resident or a PGY5 to 8 resident had a 56% (adjusted odds ratio [AOR], 1.56; 95% confidence interval [CI, 1.48‐1.64) or a 78% (AOR, 1.78; 95% CI, 1.70‐1.87) higher odds of receiving a blood transfusion, respectively. Involvement of surgical interns or junior residents (PGY1‐2), whose role in the operative procedure is assumed to be limited, was associated with a 27% higher odds of receiving a blood transfusion (AOR, 1.27; 95% CI, 1.18‐1.37). Overall, resident involvement was not associated with increased risk of 30‐day mortality (AOR, 0.97; 95% CI, 0.91‐1.04), but was associated with a slightly increased risk of complications (AOR, 1.13; 95% CI, 1.10‐1.16).

Conclusion

Senior surgery resident participation in noncardiac surgery is associated with between a 56% to 78% higher risk of receiving a blood transfusion intraoperatively compared to attending surgeons working without a resident. Assuming that senior surgical trainees are performing critical parts of the operative procedure and are less skilled than attending surgeons, the findings from this exploratory study suggest that intraoperative blood transfusion may serve as an indirect measure of surgical technical quality.
Tourism Promotion, Increasing Returns and Domestic Welfare
Authors: Shi Hui , Li Chuhui
Published: July 2013

This paper compares the effect of tourism promotion funded by commodity tax and income tax on domestic welfare in an open economy with increasing returns in the tourism and the non‐tourism sector. A promotion may overcome the under‐production of tourism goods through taking account of the implications of increasing returns, but at the same time, the taxation may have an adverse impact on the rest of the economy. Employing a general equilibrium analysis, we find that the cost of tourism promotion overcomes the benefit, reducing local residents' welfare. Furthermore, commodity tax on tourism consumption is relatively more efficient than income tax in a monopolistic competition, with less adverse impact on the variety of non‐tourism goods. We also clarify the condition for deteriorating ‘terms of trade’, which only happens when the country has a small allocation of factor endowments.
Waste Heat Recovery From Internal Combustion Engines: Feasibility Study on an Organic Rankine Cycle With Application to the Ohio State EcoCAR PHEV
Authors: Skarke Philipp , Midlam-Mohler Shawn , Canova Marcello
Published: July 2013

This paper presents a feasibility analysis on the application of Organic Rankine Cycles as a Waste Heat Recovery system for automotive internal combustion engines. The analysis is conducted considering the Ohio State University EcoCAR, a student prototype plug-in hybrid electric vehicle, as a case study for preliminary fuel economy evaluation. Starting from a energy-based powertrain simulation model validated on experimental data from the prototype vehicle, a first and second-law analysis was conducted to identify the potential for engine waste heat recovery, considering a variety of driving cycles and assuming the vehicle operating in charge-sustaining (HEV) mode. Then, a quasi-static thermodynamic model of an Organic Rankine Cycle (ORC) was designed, calibrated from data available in literature and optimized to fit the prototype vehicle. Simulations were then carried out to evaluate the amount of energy recovered by the ORC system, considering both urban and highway driving conditions. The results of the simulations show that a simple ORC system is able to recover up to 10% of the engine waste heat on highway driving conditions, corresponding to a potential 7% improvement in fuel consumption, with low penalization of the added weight to the vehicle electric range.
Grid-Convergent Spray Models for Internal Combustion Engine CFD Simulations
Authors: Senecal P. K. , Pomraning E. , Richards K. J. , Som S.
Published: July 2013

A state-of-the-art spray modeling methodology is presented. Key features of the methodology, such as Adaptive Mesh Refinement (AMR), advanced liquid-gas momentum coupling, and improved distribution of the liquid phase, are described. The ability of this approach to use cell sizes much smaller than the nozzle diameter is demonstrated. Grid convergence of key parameters is verified for non-evaporating, evaporating, and reacting spray cases using cell sizes down to 1/32 mm. Grid settings are recommended that optimize the accuracy/runtime tradeoff for RANS-based spray simulations.
Experimental Study of Methane Fuel Oxycombustion in an SI Engine
Authors: Van Blarigan Andrew , Kozarac Darko , Seiser Reinhard , Cattolica Robert , Chen Jyh-Yuan , Dibble Robert
Published: July 2013

An experimental investigation of the thermal efficiency, combustion efficiency, and CoV IMEP, of methane fuel oxycombustion in an SI engine has been carried out. Compression ratio, spark-timing, and oxygen concentration were all varied. A variable compression ratio SI engine was operated on both wet and dry EGR working fluids, with results illustrating that the efficiency of the engine operating with a large amount of EGR was significantly reduced relative to methane-in-air operation over all oxygen concentrations and compression ratios. The maximum thermal efficiency of wet EGR, dry EGR, and air was found to be 23.6%, 24.2%, and 31.4%, respectively, corresponding to oxygen volume fractions of 29.3%, 32.7% and 21%. Combustion efficiency was above 98% for wet EGR and approximately 96% for dry EGR. CoV IMEP was low for both cases. The much lower efficiency of both EGR cases relative to air is primarily a result of the reduced specific-heat ratio of the EGR working fluids relative to air working fluid.
Effect of Water Injection in Acetylene-Diesel Dual Fuel DI Diesel Engine
Authors: Lakshmanan T. , Ahmed A. Khadeer , Nagarajan G.
Published: July 2013

Gaseous fuels are good alternative fuels to improve the energy crisis of today’s situation due to its clean burning characteristics. However, the incidence of backfire and knock remains a significant barrier in commercialization. With the invention of latest technology, the above barriers are eliminated. One such technique is timed injection of water into the intake port. In the present investigation, acetylene was aspirated in the intake manifold of a single cylinder diesel engine, with a gas flow rate of 390 g/h, along with water injected in the intake port, to overcome the backfire and knock problems in gaseous dual fuel engine. The brake thermal efficiency and emissions such as NOx, smoke, CO, HC, CO2 and exhaust gas temperature were studied. Dual fuel operation of acetylene induction with injection of water results in lowered NOx emissions with complete elimination of backfire and knock at the expense of brake thermal efficiency.
Development of an Electronic Fuel Injection System for a 4-Stroke Locomotive Diesel Engine
Authors: Gautam Anirudh , Chandra Prem , Kumar Kamlesh , Sharma Mani Ram , Kumar Sanjeet , Agarwal Avinash Kumar
Published: July 2013

An electronic fuel injection system for a 4-stroke, 16 cylinders, V-configuration, medium speed, large bore locomotive diesel engine has been developed and successfully retrofitted on a rebuilt diesel locomotive. The engine employs a Pump-Line-Nozzle (PLN) system of fuel injection into the cylinder. Original fuel injection system used is a mechanical fuel injection pump connected to a mechanical fuel injector through a high pressure fuel line. The fuel injection pump meters the fuel delivery using a single helix machined on its plunger. The fuel injection timings are however optimized only for the rated speed and load resulting in non-optimised operation at other engine operating points. An electronic fuel injection pump having a solenoid valve for both fuel metering and injection timing along with ECU has been developed for retrofitment on rebuilt diesel locomotives. Interfacing of the ECU to the engine test cell controller has been done by developing suitable hardware and software. ECU calibration has been done and various maps of the engine have been developed. The engine was tested on the engine test bed. High pressure injector, modified fuel headers, fuel connection systems, a new high capacity fuel pump and layout of the wire harness were installed. After thorough testing and debugging, the EFI kit has been retrofitted on a rebuilt diesel locomotive and tested on load box followed by brief field trials. A savings of 4% fuel consumption over the duty cycle has been obtained. In addition there is an appreciable reduction in the smoke emissions during steady-state as well as transient operations.
A Fully Coupled Fluid-Structure-Interaction Model for Foil Gas Bearings
Authors: Zhang Wei , Alahyari Abbas A. , Chiappetta Louis
Published: July 2013

Foil gas bearings are self-acting, compliant-surface hydrodynamic bearings that usually use air or other process gas as their working fluid or lubricant. Foil gas bearings are made of one or more bump foils, which are compliant surfaces of corrugated metal, and one or more layers of top foil. Because foil gas bearing performance parameters, such as load capacity, are dominated by foil material and foil geometric designs, numerical models have been developed to predict the bearing’s performance based on these characteristics. However, previous models often simplify bump foil as elastic foundation with constant stiffness and neglect top foil altogether. Further, they typically use the Reynolds equation to simplify the fluid solution. In this study, ANSYS software is used to build a 3D, fully-coupled, fluid-structure-interaction model for a foil gas bearing to predict key performance parameters such as load capacity and journal attitude angle. The model’s results show good agreement with previously published test data. This not only demonstrates the feasibility of 3D fully coupled fluid-structure-interaction model for a conventional foil bearing using commercial codes, but also shows modeling capability for future generations of foil gas bearing.
Elasto-Plastic Analysis of a Contact Under Normal and Torque Loading
Authors: Li Pengyang , Wang Zhanjiang , Chen W. Wayne , Jin Xiaoqing , Li Yan , Wang Q. Jane
Published: July 2013

A spinning rigid sphere pressed against an elasto-plastic half space under combined normal and torque loading is presented. The elastic results based on present method are compared with an analytical solution to validate the current model. Stresses, strains, and residual displacements are investigated. The effects of friction coefficient on the spinning and half space contacts are studied. The surface pressure, subsurface stress, von Misses stress, the first yield point, plastic strain fields and evolution of the plastic region are further analyzed. Results show that the application of the torque shifts the maximum von Mises stress and plastic region in the half space closer to the surface; the whole plastic region also moves near the surface. Moreover, the position of the first yield points becomes closer to the surface as well; the evolution of the plastic region shows more complex shapes than those only under a normal load condition.
Effect of Surface Microtexturing on Friction at Unidirectional Sliding Depending on Lubricant Viscosity
Authors: Zum Gahr Karl-Heinz , Mann Mario
Published: July 2013

Effect of surface microtexturing with spherical dimples of 60 μm diameter on friction behaviour of steel 100Cr6/sapphire pairs was studied as function of lubricant viscosity. Tests were run at unidirectional sliding up to 0.30 m/s using a pellet-on-disc geometry with flat contact area and drip lubrication with liquids such as glycerine-water solutions, distilled water and different mineral oils without additives. The texture pattern was produced on the polished sapphire discs by laser ablation processes. Friction force and film thickness of the lubricating liquid were continuously measured during the tests at different sliding velocities. Results showed that effectiveness of microtexturing in reducing friction and increasing load-carrying capacity depended on viscosity of the lubricant, operating conditions such as sliding velocity and applied load as well as texture parameters.
Behaviour of Magnetic Fluid Based Rough Rayleigh Step Bearing
Authors: Patel P. A. , Deheri G. M. , Patel A. R.
Published: July 2013

The Rayleigh step bearing is considered in one dimensional geometry. It is a well established fact that the roughness has a significant effect on the performance of the hydrodynamic lubrication of a slider bearing. An attempt has been made to study and analyze the effect of transverse roughness in the presence of a magnetic fluid for a Rayleigh step bearing. The bearing surfaces are assumed to be transversely rough. The roughness of the surfaces has been characterized by a random variable with non-zero mean, variance and skewness. The stochastically averaged Reynolds equation is solved with suitable boundary conditions to obtain the pressure distribution in turn, which is used to get the load carrying capacity. The results presented in graphical form indicate that the effect of transverse roughness is significantly adverse. However, this article establishes that there exist sufficient scopes for improving the performance of the bearing system in the case of negatively skewed roughness especially, when negative variance is involved, in spite of the fact that the standard deviation introduces a negative effect. Besides, the performance of the bearing system improves significantly owing to the presence of the magnetic fluid lubricant. The adverse effect of roughness can be minimized by the positive effect of magnetization at least in the case of negatively skewed roughness. Therefore, this investigation offers some measures even from bearing’s life period point of view.
Determination of Fundamental Parameters for the Cross-Hatched Cylinder Liner Micro-Geometry
Authors: Biboulet N. , Sainsot P. , Lubrecht A. A.
Published: July 2013

Energy savings and limited polluting emissions are crucial for the automotive industry. The micro-geometry of the cylinder-liner-piston-ring contact is studied. Functional parameters are analysed on liners at different number of fired cycles.
Pressure Increase in Elliptical Impact EHL Contacts With Surface Asperities
Authors: Kaneta M. , Guo F. , Wang J. , Krupka I. , Hartl M.
Published: July 2013

The phenomena which occur when a spherical steel body impacts a stationary steel plate with surface asperities are discussed through isothermal Newtonian numerical analysis using sinusoidal roughness. The ridges of the sinusoidal roughness produce large local pressures, particularly in elliptical contacts, when constant loads are imposed on the contact by impact. The pressure level is usually larger when the ridges are located along the major contact direction than along the minor contact direction, and increases as the loading speed increases. The high pressure induces a micro-groove in the ridge and the horse-shoe shaped constriction is formed at the ridges locating around the contact edge.
Flying Height Control Using Dual Thermal Protrusions in Heat Assisted Magnetic Recording (HAMR)
Authors: Xiong Shaomin , Li Liping , Bogy David B.
Published: July 2013

Thermal flying height (TFC) control technology has been used in the past few years to achieve a lower flying height for higher storage areal density. In this paper, a slider with dual thermal protrusion, one produced by the laser used to heat the disk in HAMR and the other one used for TFC, is programmed with feedback control to reduce the flying height modulation (FHM) due to disk waviness and to attenuate the external disturbances. A numerical simulation is conducted to investigate the feasibility of the system. The results show that FHM of the dual protrusion slider is reduced significantly when the protrusion heights and locations are optimized. External disturbance induced FHM can be suppressed as well. This scheme can benefit HAMR because it will provide a more consistent flying height and more freedom to compensate external disturbances.
Behavior of O/W Emulsion Under Point Contact
Authors: Ma Liran , Luo Jianbin , Zhang Chenhui
Published: July 2013

Worldwide efforts to illuminate the behavior of multiple-phase liquid are frequently focused on oil-in-water emulsions. With the aim to reveal the machanism of the film formation of aqueouse emulsion in confinement, we observed the behavior of O/W confined in a nanogap. We have observed the oil pool formed surrounding the contact area in the inlet, derived from the oil film adhered on the solid surfaces, as well as the research into how the oil pool changes with rolling speed and feeding mode. Two regions have been found in the outlet area, which are defined as vaccum region and turn-round region. Small droplets have been observed to turn round in the turn-round region, with a diminishing droplet-size distribution. Moreover, by employing two different feeding modes, we have demonstrated a suprising discovery diametrically opposed to the traditional concept. The film formation has been detedcted to be distinctly enhanced under an insufficient feeding condition compared to the situation under a sufficient feeding condition. The unusual performance leads to an strong evidence of the reemulsification concept. Here, we demonstrate, directly from experimentally observations of emulsion behaivors, that the film formation of emulsion is significantly affected by the droplet behavior.
Effect of Surface Roughness and Lubricant on Scuffing Initiation
Authors: Han Jiman , Zou Qian
Published: July 2013

Scuffing failure generally occurs at oil film breakdown and large amount of metal-to-metal interaction between the contacting surfaces, where the role of surface roughness and lubricant becomes prominent. In order to evaluate the effect of surface roughness and lubricant on scuffing, scuffing simulation was carried out using contact mechanics and plasto-elastohydrodynamic lubrication model (MixedPEHL) by taking into account the plastic deformation in the contact area. The evolution of pressure, film thickness, contact area ratio, and subsurface effective plastic strain (EPS) was performed with three types of surface roughness and two different lubricants. Comparisons of pressure distribution, film thickness distribution, film thickness to surface roughness ratio (λ ratio), and contact area ratio were described to investigate the effect of surface roughness and lubricants on scuffing behavior. A better understanding on the effect of surface roughness and lubricant on scuffing processes was obtained through the research work.
Non-Uniform Behavior of Lubricant Flow According to Surface Texturing Distribution
Authors: Higuera-Garrido A. , Wang C. , González R. , Báttez A. H. , Sadeghi F.
Published: July 2013

This study presents and discusses how the lubricant film flows in and around the dimples of a textured surface. Currently some authors assume that the emptying of the dimples starts in their front edge (according to the lubricant’s flow), but several tests, with different texturing densities and distances, have showed that this behavior can only be seen in the first row of dimples or, if distance is long enough, in the following rows. However, in those cases where rows are closely distributed (high texturing densities) the emptying of the dimples shows two lateral fronts instead of a frontal one.

The study led to the following conclusions: the way pockets are emptied depends on their distribution and position in the dimples’ array; frontal emptying phenomenon is only present at first row dimples or when distance between rows is long enough; when surrounding pockets modify how the lubricant reaches the dimple, the frontal emptying phenomenon becomes a bi-edged one, with two emptying fronts instead of one; as surface texturing requires a huge number of pockets at usually high texturing densities, it can be asserted than the frontal emptying phenomenon is not the most common one even though it’s the one that several authors use to study the emptying phenomenon.
Experimental Study of Lubrication Film Formation in Multiple Contacts Device Under Starved Conditions
Authors: Svoboda Petr , Kostal David , Krupka Ivan , Hartl Martin
Published: July 2013

Some machine elements such as gears, rolling bearings, cams and traction drives operate under starved lubrication conditions where the average lubricant film thickness is considerably less than under fully flooded conditions. These parts must operate correctly, often over prolonged periods with sufficient performance. One of the most important parameters determining the performance and life of machine parts is a lubrication film thickness, which is generated within elastohydrodynamic lubricated (EHL) non-conformal contacts. The film thickness in this regime is often time dependent and its value is governed by lubricant supply. If loss outstrips supply this leads to very thin films, which can no longer fulfill their role of separating the surfaces, and thus component failure can result. To achieve optimum bearing performance and component life, it is obviously desirable to be able to predict when starvation will occur. Today the film thickness and pressure in EHL can be predicted using numerical models also in the case of starvation. Although it is very essential to solve the starved EHL problems very little work aimed at comparing experiment and theory has been done. Especially in the case where the starved lubrication model requires as input the inlet layer thickness. This is crucial if the validity of numerical models is to be properly established. This paper is focused on the study of starved lubrication conditions on lubrication film formation. A new optical test rig with multiple EHL contacts was developed for experimental study of lubrication film formation.
Determination of Adhesion Forces Between Smooth and Structured Solids
Authors: Fischer Hartmut R. , Gelinck Edwin R. M.
Published: July 2013

The tendency of smooth surfaces to stick spontaneously to each other is becoming a serious problem, with: a) the increasing quality in surface finish for many components and systems, b) on miniaturization in mechanical components, and c) in demanded precision of positioning of parts in high-end equipment machines and systems. Surfaces tend to be made smoother in order to gain flatness or in order to fulfill the need for more precise and reproducible positioning of parts. Adhesion or even sticking of the surfaces is a major showstopper for these applications.

There are several measures that can be taken in order to reduce spontaneous adhesion. Quantification of the effectiveness of the chosen solution is most often done using an AFM with probes varying from 1 nm to 8 micron of contact diameter. A serious disadvantage in measuring adhesion by sharp tips is the wear of the tips. Sharp tips wear easily, resulting in undefined contact areas. When the real area of contact is not well defined, the quantification of the adhesion force is not significant.

In the current study results of AFM measurements from literature with different tip diameters of colloidal probes are compared with measurements we performed using AFM cantilevers with a plateau tip and using probes from large spheres using an alternative setup (UNAT). These methods give results that are in good agreement with values found in literature. Large contacting surface enhance the quality of the measured adhesion values.

Another part of the study deals with a deliberately roughening of smooth surfaces to minimize (spontaneous) adhesion. Good agreement has been found with existing results.

For the use of larger surfaces it is important that the surfaces to be tested are extremely clean. Particles on smooth surface do influence the measurements quite easily. Especially for larger areas, the possibility of encountering particles on the surface are more likely, when particles are present. For the measurements in this study a lot of care has been taken therefore to remove contamination: particles as well as contamination of organic origin.
Simultaneous Measurements of Friction Forces and Contact Areas During Shearing of Nanometer-Thick Liquid Lubricant Films
Authors: Itoh Shintaro , Mizuno Takumi , Norizuki Yusuke , Fukuzawa Kenji , Zhang Hedong
Published: July 2013

Nanometer-thick liquid lubricant films are useful for the lubrication of miniaturized mechanical systems, such as hard disk drives or microelectromechanical systems. However, there are no established methods for measuring the mechanical properties of such thin films, which can be an obstacle to the optimal design of lubrication systems. We previously developed a highly sensitive method for measuring shear forces, which we called the fiber-wobbling method (FWM). In the FWM, we used a ball-ended optical fiber to probe shear and we measured the friction force acting on the probe tip by detecting the deflection of the fiber. By this means we succeeded in measuring friction forces in nanometer-thick liquid lubricant films. However, we could not evaluate the mechanical properties of the films quantitatively because the contact area between the probe tip and lubricant film was unknown. Here, we developed a method for measuring the contact area during shearing of nanometer-thick liquid lubricant films in the FWM.
Adaptive Solid Lubricant Transfer Films for Conductivity and Oxidation Control
Authors: Dougherty Patrick S. M. , Sunday Cecily M. , Higgs C. Fred
Published: July 2013

The success of solid lubricants to exhibit ultra-low friction and wear behaviors in oil-prohibiting environments, has led to a major effort to optimize their performance and enhance their applicability. Depending on the operating conditions, solid lubricants may take on a plethora of forms including fabricated composite coatings, thick-film powder lubricants, nano-particle additives for hard surfaces or liquid lubricants, and self-replenishing transfer films. One of the benefits of transfer films are their freedom from the complex deposition techniques required for most other solid lubricant systems. In this work, the potential for adaptive self-replenishing transfer films was explored by creating composite powders of well-known powder lubricants and electrically conductive or anti-oxidation materials. MoS2, WS2, and Graphite Powders were mixed in varying composition with Cu, Sb2O3, and BO3 additives and compacted to form “tuned” or adaptive powder pellets. Relationships between friction, wear, electrical resistance, tribo-induced oxidation and powder composition, will be presented in order to investigate the potential of composite property optimization for lubricious, highly conductive, and oxidation resistant transfer films.