bluuebunny/crossref_metadata_2025 huggingface dataset:
Heterotrimeric G protein mediates ethylene‐induced stomatal closure via hydrogen peroxide synthesis in Arabidopsis
Authors: Ge Xiao‐Min , Cai Hong‐Li , Lei Xue , Zhou Xue , Yue Ming , He Jun‐Min
Published: February 2015

Heterotrimeric G proteins function as key players in hydrogen peroxide (H2O2) production in plant cells, but whether G proteins mediate ethylene‐induced H2O2 production and stomatal closure are not clear. Here, evidences are provided to show the Gα subunit GPA1 as a missing link between ethylene and H2O2 in guard cell ethylene signalling. In wild‐type leaves, ethylene‐triggered H2O2 synthesis and stomatal closure were dependent on activation of Gα. GPA1 mutants showed the defect of ethylene‐induced H2O2 production and stomatal closure, whereas wGα and cGα overexpression lines showed faster stomatal closure and H2O2 production in response to ethylene. Ethylene‐triggered H2O2 generation and stomatal closure were impaired in RAN1, ETR1, ERS1 and EIN4 mutants but not impaired in ETR2 and ERS2 mutants. Gα activator and H2O2 rescued the defect of RAN1 and EIN4 mutants or etr1‐3 in ethylene‐induced H2O2 production and stomatal closure, but only rescued the defect of ERS1 mutants or etr1‐1 and etr1‐9 in ethylene‐induced H2O2 production. Stomata of CTR1 mutants showed constitutive H2O2 production and stomatal closure, but which could be abolished by Gα inhibitor. Stomata of EIN2, EIN3 and ARR2 mutants did not close in responses to ethylene, Gα activator or H2O2, but do generate H2O2 following challenge of ethylene or Gα activator. The data indicate that Gα mediates ethylene‐induced stomatal closure via H2O2 production, and acts downstream of RAN1, ETR1, ERS1, EIN4 and CTR1 and upstream of EIN2, EIN3 and ARR2. The data also show that ETR1 and ERS1 mediate both ethylene and H2O2 signalling in guard cells.
A socially realistic view of world Englishes: Reflections on gendered discourse
Authors: VALENTINE TAMARA
Published: February 2015

The work of Braj Kachru and Yamuna Kachru has inspired generations of scholars to take a socially realistic view of the global spread of English. It is the work of Yamuna Kachru, however, who argues that taking an integrative sociocultural approach to the study of world Englishes to examine linguistic interaction expresses not only the bilingual's creativity but also provides valuable methodological and theoretical insights into the discoursal structure in world Englishes. Adopting the sociocultural linguistic approach, this paper examines how speakers construct gender in Indian English discourse. Using examples from naturally occurring spoken conversations, this paper shows that the interplay between language and identity is rooted in the cultural beliefs and values of speakers. The socially realistic approach contextualizes the culture of language to explain language variation in the Outer Circle.
Improving Secondary Prevention Screening in Clinical Encounters Using mHealth Among Prelicensure Master's Entry Clinical Nursing Students
Authors: FitzGerald Leah Z. , Rorie Anne , Salem Benissa E.
Published: February 2015

Aims

To determine the feasibility and acceptability of a mHealth application among nursing students for health promotion and secondary prevention health recommendations for hospitalized adult patients.

Methods

A pretest–posttest design with a convenience sample of 169 prelicensure master's entry clinical nursing students in a large urban public university. Survey questions assessed intention to use, perceived usefulness, perceived ease of use, subjective norm, voluntariness, clinical area relevance, output quality, and result demonstrability of the United States Preventive Services Task Force (USPSTF) evidence‐based practice guidelines via the mHealth application.

Results

Descriptive statistics and frequencies were used to explore sociodemographics; paired t‐tests were used to evaluate pre‐ and posttest differences. Pre‐ and posttest significant differences (p < .01) were found between intention to use, perceived usefulness, subjective norm, voluntariness, image, clinical relevance, result demonstrability, and output quality (p < .02). Ease use of a mHealth application was not significantly different.

Linking Evidence to Action

These findings highlight the need to integrate evidence‐based practice tools using mHealth technology among prelicensure master's entry clinical nursing students in order to engage and foster translational learning and improve dissemination of secondary prevention screening guidelines among hospitalized patients.
Warpage Characterization of Microchannels Fabricated by Injection Molding
Authors: Çetin Barbaros , Koska A. Koray , Erdal Merve
Published: February 2015

Mass-production of microfluidic devices is important for biomedical applications in which disposable devices are widely used. Injection molding is a well-known process for the production of devices on a mass scale at low-cost. In this study, the injection molding process is adapted for the fabrication of a microfluidic device with a single microchannel. To increase the product quality, high-precision mechanical machining is utilized for the manufacturing of the mold of the microfluidic device. A conventional injection molding machine is implemented in the process. Injection molding was performed at different mold temperatures. The warpage of the injected pieces was characterized by measuring the part deformation. The effect of the mold temperature on the quality of the final device was assessed in terms of the part deformation and bonding quality. From the experimental results, one-to-one correspondence between the warpage and the bonding quality of the molded pieces was observed. It was found that as the warpage of the pieces decreases, the bonding quality increases. A maximum point for the breaking pressure of the bonding and the minimum point for the warpage were found at the same mold temperature. This mold temperature was named as the optimum temperature for the designed microfluidic device. It was observed that the produced microfluidic devices at the mold temperature of 45 °C were able to withstand pressures up to 74 bar.
Research on the Obtainment of Topography Parameters by Rough Surface Simulation With Fast Fourier Transform
Authors: Fei He Yan , Yuan Tang Jin , Zhou Wei , Ri Liao Dong
Published: February 2015

Asperity radius of curvature and asperity density, which are generally obtained from rough surface simulation with fast Fourier transform (FFT), are the two essential parameters for statistical contact model. In simulation, however, the value of a parameter (defined as “autocorrelation function (ACF) truncation length” in this paper), which is arbitrarily chosen and has been paid little attention to in most relevant literature, is found to have a great effect on topography parameters, regardless of the methods chosen to calculate them. Improper determination of the ACF truncation length may induce erroneous results. This paper points out how to make the proper determination of the ACF truncation length to guarantee a certain degree of precision and explains why improper determination of the ACF truncation length may cause serious errors when calculating the topography parameters. Besides, the asperity radius of curvature and the asperity density of the generated rough surfaces are calculated using the eight-summit identification method, and their formulae in terms of correlation length are obtained through numerical fitting.
Achieving Heat Flux Uniformity Using an Optimal Arrangement of Impinging Jet Arrays
Authors: Forouzanmehr M. , Shariatmadar H. , Kowsary F. , Ashjaee M.
Published: February 2015

In order to achieve uniform distribution of heat flux over an isothermal heated target surface, a numerical algorithm is developed to obtain an optimized array of four laminar impinging slot jets. Root mean square deviation of the local Nusselt distribution from the desired Nusselt number is considered as the objective function. Jets' widths, jet-to-jet and jet-to-surface spacings, and the overall flow rate are chosen as design variables. Conjugate gradients method along with backtracking line search is applied to optimize the objective function calculated by numerical simulation for three different cases of Nu = 7, 9, and 11. For each of these desired Nusselt numbers, an almost uniform distribution of local Nusselt number with percent of root mean square error less than 2.5% is achieved in fewer than 12 iterations. An experimental study using a Mach–Zehnder interferometer (MZI) has been performed. The measured distribution of local Nusselt number is in good agreement with numerical results in all three optimal configurations.
Optimization of Printed Circuit Heat Exchanger Using Exergy Analysis
Authors: Lee Sang-Moon , Kim Kwang-Yong
Published: February 2015

A printed circuit heat exchanger (PCHE) with zigzag flow channels in a double-faced configuration was optimized to enhance its thermal–hydraulic performance. Using exergy analysis, the objective function was defined as the net exergy gain of the system considering the exergy gain by heat transfer and exergy loss due to friction in the channels. A Reynolds-averaged Navier–Stokes (RANS) analysis and surrogate modeling techniques were used for the optimization. Three geometric variables were selected as the design variables. The objective function was calculated at each design point through RANS analysis in order to construct a response surface surrogate model. Through the optimization, both the thermal and hydraulic performances of the PCHE were improved with respect to the reference geometry by suppressing flow separation in the channels.
Multiconfiguration Shape Optimization of Internal Cooling Systems of a Turbine Guide Vane Based on Thermomechanical and Conjugate Heat Transfer Analysis
Authors: Wang Bingxu , Zhang Weihong , Xie Gongnan , Xu Yingjie , Xiao Manyu
Published: February 2015

This study concerns optimization of shapes, locations, and dimensions of internal cooling passages within a turbine vane under severe environments. The basic aim is to achieve a design that minimizes the average temperature and ensures the structural strength. Considering the prohibitive computational cost of 3D models, numerical optimization process is performed based on 2D cross-sectional models with available experimental temperature data as boundary conditions of thermomechanical analysis. To model the cooling channels, three kinds of shape configurations, i.e., circle, superellipse, and near-surface holes, are taken into account and compared. Optimization results of 2D models are obtained by using a globally convergent method of moving asymptotes (GCMMA). Furthermore, full conjugate heat transfer (CHT) analyses are made to obtain temperature distributions of 3D models extruded from 2D ones by means of shear stress transport (SST) k-ω turbulence model. It is shown that optimization of cooling passages effectively improves the thermomechanical performances of turbine vanes in comparison with those of initial C3X vane. The maximum temperature of optimized vane could be reduced up to 50 K without degrading mechanical strength.
Optimal Shapes of Straight Fins and Finned Heat Sinks
Authors: Lindstedt Matti , Lampio Kaj , Karvinen Reijo
Published: February 2015

Finned heat sinks are used to cool power electronics components. We present optimization results for single rectangular, triangular, and trapezoidal fins. After that, we minimize the mass of an existing heat sink consisting of a base plate and a fin array by optimizing the geometrical variables and component locations on the base plate. An analytical solution is used with rectangular fins and a numerical model with trapezoidal fins. Whereas the triangle is the best shape for single fins, in a heat sink flow velocity coupled with geometry favors trapezoids over triangles and rectangles.
A Cloud Manufacturing Architecture for Complex Parts Machining
Authors: Liu Xu , Li Yingguang , Wang Lihui
Published: February 2015

Service provider (SP) know-hows are essential in machining service (MS) encapsulation in the cloud. However, since the acquisition of the know-hows for complex parts machining requires investing considerable manpower and resources in R&D, this kind of machining know-hows is usually considered as one of the core competences of the SP who makes them unshareable. Targeting the problem, this paper presents a new cloud manufacturing (CM) architecture in which MSs are encapsulated within each SP with standardized machining task description strategies (SMTDS). Only the capability information about what the SP can do is provided to the cloud. During service matching, SMTDS is also applied for user request formulation to improve the matching efficiency and quality. For complex parts in large size, high machining requirements, high value, short delivery cycle, and complex structures, e.g., aircraft structural parts, unacceptable machining quality or delivery delay may cause a much greater loss not only in economy. In the proposed CM architecture, to guarantee the feasibility of the MSs for complex structural parts, machining operations for the user preferred services could be generated by mapping the corresponding typical machining plans (TMP) to the part based on the dynamic feature concept to support accurate evaluations of the MSs. The machining of an aircraft structural part is then applied as a test user request to demonstrate how the proposed method works for finding MS for complex parts.
Effects of Nonconventional Tools on the Thermo-Mechanical Response of Friction Stir Welded Materials
Authors: Lampeas George N. , Diamantakos Ioannis D.
Published: February 2015

An investigation on the effect of two alternative friction stir welding (FSW) tool designs, namely, Bobbin tool and DeltaN tool, on the temperature profile, residual stress (RS), and distortion fields developing during FSW process is presented. The study is based on the semi-analytical calculation of the total heat generated during FSW. Subsequently, the calculated heat energy is applied as thermal load in a three-dimensional finite element (FE) thermo-mechanical model for the calculation of temperature history, RSs, and distortions. The overall methodology is validated through the comparison of the numerical results to respective experimental temperature measurements and distortions observations.
Characterizing Effects of the Shape of Screw Conveyors in Gas–Solid Fluidized Beds Using Advanced Numerical Models
Authors: Xiong Qingang , Aramideh Soroush , Passalacqua Alberto , Kong Song-Charng
Published: February 2015

A numerical study of the effects of the shape of an enclosed screw conveyor on the mixing and heat transfer in a horizontal gas–solid fluidized bed was conducted using computational fluid dynamics (CFD). A two-fluid model (TFM) was employed to model the gas and solid phases as continua through mass, momentum, and energy conservations. The motion of the screw conveyor was simulated by using a rotating reference frame (RRF) such that the computational mesh was free from dynamic reconstruction. The diameters of the screw flight and shaft, the pitch, and the blade thickness were varied in the parametric study. Under the operating conditions studied, it was found that the increase in the diameter of the screw flight results in the enhancement of the solid mixing and conveyance. The increase in the diameters of the screw shaft and the screw blade thickness lead to the enhanced solid mixing but reduced conveyance. The variation in the screw pitch gives rise to rather complex behaviors in the solid mixing and conveyance. As the screw pitch is decreased, the solid mixing increases initially but then decreases before it increases eventually. The solid conveyance capability was found to first increase and then decrease. Explanations to the effects of the shape of the screw conveyor were discussed in this work.
Effects of Exhaust Gas Recirculation and Boost Pressure on Reactivity Controlled Compression Ignition Engine at High Load Operating Conditions
Authors: Wu Yifeng , Reitz Rolf D.
Published: February 2015

Reactivity controlled compression ignition (RCCI) at engine high load operating conditions is investigated in this study. The effects of exhaust gas recirculation (EGR) and boost pressure on RCCI combustion were studied by using a multidimensional computational fluid dynamics (CFD) code. The model was first compared with a previous CFD model, which has been validated against steady-state experimental data of gasoline–diesel RCCI in a multicylinder light duty engine. An RCCI piston with a compression ratio of 15:1 was then proposed to improve the combustion and emissions at high load. The simulation results showed that 18 bar indicated mean effective pressure (IMEP) could be achieved with gasoline–diesel RCCI at an EGR rate of 35% and equivalence ratio of 0.96, while the peak pressure rise rate (PPRR) and engine combustion efficiency could both be controlled at reasonable levels. Simulations using both early and late direct-injection (DI) of diesel fuel showed that RCCI combustion at high load is very sensitive to variations of the EGR amount. Higher IMEP is obtained by using early diesel injection, and it is less sensitive to EGR variation compared to late diesel injection. Reduced unburned hydrocarbon (HC), carbon monoxide (CO), soot and slightly more nitrogen oxides (NOx) emissions were seen for early diesel injection. HC, CO, and soot emissions were found to be more sensitive to EGR variation at late diesel injection timings. However, there was little difference in terms of peak pressure (PP), efficiencies, PPRR, and phasing under varying EGR rates. The effect of boost pressure on RCCI at high load operating conditions was also studied at different EGR rates. It was found that combustion and emissions were improved, and the sensitivity of the combustion and emission to EGR was reduced with higher boost pressures. In addition, cases with similar combustion phasing and reasonable PPRR were analyzed by using an experimentally validated GT-Power model. The results indicated that although higher IMEP was generated at higher boost pressures, the brake mean effective pressure (BMEP) was similar compared to that obtained with lower boost pressures due to higher pumping losses.
Dimensionless Study on Efficiency and Speed Characteristics of a Compressed Air Engine
Authors: Yu Qihui , Cai Maolin , Shi Yan , Yuan Chi
Published: February 2015

To eliminate the pollutants exhausting, this paper presents an idea of using compressed air as the power source for engines. Instead of an internal combustion (IC) engine, this automobile is equipped with a compressed air engines (CAEs), which transforms the energy of the compressed air into mechanical kinematic energy. Through analysis of the working process of a CAE, the mathematical model is setup. Experiments are carried out to verify the engine performance and the basic model’s validity. By selecting the appropriate reference values, the mathematical model is transformed to a dimensionless expression. The dimensionless speed and efficiency characteristics of the CAE are obtained. Through analysis, it can be obtained that the dimensionless average rotating speed is mainly determined by the intake duration angle, the dimensionless inertia parameter, the dimensionless exhaust pressure, and the scale factor of exhaust valve. Moreover, the efficiency of the CAE is mainly determined by the dimensionless exhaust pressure, the intake duration angle and the dimensionless cylinder clearance. This research can be referred to in the design of CAE and the study on optimization of the CAE.
Long-Term Wave Power Statistics for Individual Waves
Authors: Leira Bernt J. , Myrhaug Dag
Published: February 2015

The paper provides long-term bivariate distributions of wave power with wave height, and wave power with wave period. This is relevant for assessments of wave power devices and their potential for converting energy from waves. The results can be applied to compare systematically the wave power potential for individual waves at different locations based on short-term statistical description of the individual waves and the long-term statistical information of the wave climate. Furthermore, it allows for assessment of the efficiency of a given wave power device for each location.
Heat Transfer, Pressure Drop, and Entropy Generation in a Solar Collector Using SiO2/Water Nanofluids: Effects of Nanoparticle Size and pH
Authors: Mahian Omid , Kianifar Ali , Sahin Ahmet Z. , Wongwises Somchai
Published: February 2015

In this paper, an analytical study is carried out on the heat transfer, pressure drop, and entropy generation in a flat-plate solar collector using SiO2/water nanofluid with volume concentration of 1%. In the study, the effects of two different values of pH, i.e., 5.8 and 6.5, and two different sizes of nanoparticles, i.e., 12 nm and 16 nm, on the entropy generation rate in turbulent flow are investigated. The results are compared with the results obtained for the case of water. The findings show that by using the Brinkman model to calculate the viscosity instead of experimental data one obtains a higher heat transfer coefficient and thermal efficiency than that in the case of water, while, when the experimental data are used, the heat transfer coefficient and thermal efficiency of water are found to be higher than that of nanofluids. The results reveal that using nanofluids increases the outlet temperature and reduces the entropy generation rate. It is also found that for nanofluids containing the particles with a size of 16 nm, the increase in pH value would increase the entropy generation rate, while for nanoparticles with a size of 12 nm the increase in pH would decrease the entropy generation.
Development of a Damper Control System for Combined Cycle Thermal Gas Power Plant
Authors: Mondal Amit Kumar , Devalla Vindhya , Kaundal Vivek , Bansal Kamal
Published: February 2015

This paper addresses a technique to solve the problem of heat dissipation in solenoid coil of the solenoid valve which is controlling the hydraulic damper by using pulse width modulation (PWM) switching technique with low frequency. In addition to this damper controlling is achieved via wireless controlling. By using PWM based low frequency switching technique the gas turbine trip will be protected. PWM is achieved by microcontroller and wireless control is done by ZigBee.
Yield Surface Investigation of Alloys During Model Disk Spin Tests
Authors: Servetnik Anton N. , Kuzmin Evgeny P.
Published: February 2015

Results of quasi-static numerical simulation of spin tests of model disk made from high-temperature forged alloy are presented. To determine stress-strain state of disk during loading finite element analysis is used. Simulation of elastic-plastic strain fields was carried out using incremental theory of plasticity with isotropic hardening. Model sensitivity from Von mises and Tresca yield conditions and hardening conditions was investigated. To identify the material model parameters an experimental approach of rim radial displacement measurement by eddy currents sensor during the load-unload of spin test was used. Calculation made using different material models were compared with the experimental results.
Simulation of Accessory Drives Bevel Gears Dynamic Conditions
Authors: Kozharinov Egor , Temis Jury
Published: February 2015

Bevel gears of modern aviation motors operate at high rotation velocities and transmitted torques. High dynamic load in bevel mesh due to impact interaction of teeth in contact actuates gear rim oscillations. Coincidence of dynamic load frequency and bevel gear natural frequency of nodal diameter can cause oscillation amplitude grow and gear rim breakdown. By harmonic response analysis it is shown, that highest stresses in gear rim appears during gear oscillation by two or three nodal diameters. Gear root is a stress concentration in this case.

In this paper methods of bevel gears dynamic behavior simulation are considered. A 3D solid dynamic model of bevel gear drive with transient contact interaction between pinion and gear by curvilinear teeth subject to tooth profile modification has been developed. An actuation was made by kinematic way by applying rotational velocity to driving pinion. A transmitted torque is applied to driven gear. An energy dissipation in gear material is considered in model.

A transmission error of bevel gears depending on profile modification, transmitted torque and diaphragm stiffness is calculated. It is shown, that applying tooth profile modification helps to avoid stress concentration on teeth flank, decreases transmission error and derivatives of it’s function.

As a result of calculation a function of disturbing force, actuating in gear mesh, dynamic transmission error and first principal stresses of gear crown face in time domain has been obtained. A spectral analysis of disturbing force and first principal stresses of gear rim is executed. As a result, it is shown, that gearing mesh is a source of poly-harmonic excitation of bevel gears. The maximum amplitude in contact force spectra is at frequency four times greater, than tooth frequency, and the maximum amplitude in first principal stresses of gear crown face spectra is at tooth frequency. Using a first principal stresses law of variation a new criterion of bevel gear rim strength is obtained.
Analysis of Flow Through a Twisted Vaned Diffuser
Authors: Pothuri Venkateswara Rao , Govindaraju Venkata Ramana Murty , Ganapathiraju Venkata Rao
Published: February 2015

This paper describes the computational results on the performance of a centrifugal compressor stage with twisted vaned diffuser by varying the speed of the impeller and direction of twist for the diffuser vane. The centrifugal compressor stage configuration consists of a 2-D impeller (no twist is provided for the impeller vanes) with various configurations of diffusers. Diffuser configurations considered are Vaneless Diffuser (VLD), Low Solidity Vaned Diffuser (LSVD) and Twisted Vaned Diffuser (TVD). The analysis was carried at four different rotational speeds with corresponding mass flow rates of the impeller. 9° twist is given to the diffuser vane from hub to shroud by providing rotation at the leading edge, keeping the profile at hub as reference in the direction of rotation of the impeller and opposite to the direction of rotation of the impeller. The off-design cases considered includes operation at 80%, 90%, 110% and 120% of the design mass flow rate. CFD results are validated with experimental results for stages with VLD and LSVD for certain chosen performance parameters such as head coefficient, stage input power and exit flow angle. The computational results indicate that variations in impeller speed will cause changes in all significant performance parameters like the total pressure rise, power coefficient and efficiency of the stage and static pressure recovery coefficient of the diffuser. Contour plots were generated from CFD results and analyzed for better understanding of effect of rotational speed of the impeller on the performance of the centrifugal compressor. As a result of this study, it can be concluded that twisted vaned diffuser improves the performance in comparison to low solidity vaned diffuser for all the chosen impeller rotational speeds. The performance of the compressor stage is superior when diffuser vane twist is provided in the direction opposite to the rotation of impeller.
Account the Mutual Influence of the Simulation Components of GTE
Authors: Krivcov Alexander , Shabliy Leonid , Baturin Oleg
Published: February 2015

In this paper, we present a methodology to integrated simulation of gas turbine engine (GTE). This method allow to predict performance of GTE components workflows with account the mutual influence. Steady state CFD modeling of compressor, combustion chamber and the turbine are demonstrated. Solution is provided in separate solvers step by step. Efforts to decide some problem of matching models are written. Author shows the accuracy level of boundary data achieved with this approach.
Studies on the Impact of Choice of Gas Models in an Un-Cooled Turbine Stage
Authors: Srinivasan Karthik , Newman David , Patil Abhilash
Published: February 2015

CFD analysis has already been established as a preferred way of evaluating turbine stage performance and any incremental increase to it through component design changes. The usually overlooked assumption during a CFD simulation is the choice of gas model. In turbomachinery analysis, for quick assessment of stage performance, modeling the fluid as perfect gas has been yielding fairly reliable results. In general the consideration of real gas effects has been less popular; although they are more realistic. The paper presents the comparison of aero-thermal predictions of an un-cooled turbine stage using ideal and real gas models based on CFD studies only. In addition, the impact of gas models on stage performance predicted using steady state and unsteady CFD analysis is also presented. Based on steady state CFD evaluations, the stage efficiency variation with the change of gas model is less than 0.3% with the real gas effect indicating lower efficiency. However, the unsteady predictions indicate that the time averaged stage efficiency predicted using perfect gas model can be 1% higher than that predicted using real gas model.
Numerical Investigation of Pilot-Stabilized Turbulent Flames Using Steady Flamelet Model
Authors: Dongre Akshay , De Ashoke
Published: February 2015

In the present paper, 2D RANS simulations have been carried out to simulate the Sydney pilot-stabilized turbulent flames using the steady and unsteady flamelet (SF and USF) approach. The flamelet model provides an alternative to computationally exhaustive probability density function (PDF) based approach. The primary focus of this study is to assess the accuracy and applicability of the flamelet methodology to model pilot-stabilized flames, having different fuel composition, by studying the effects of velocity and fuel composition on the flame structure. From the results, it is observed that the steady flamelet model captures the radial profiles of mean axial velocity and turbulent kinetic energy with reasonable accuracy but over-predicts the mean temperature profiles significantly. Although SF captures the profiles of CO, H2, CO2, and H2O adequately, it does not show much deviation between predictions as the jet velocity approaches the blow-off limit for studying the effect of jet velocity variation on the flame structure. For flames closer to blow-off, the peak values for the product species are found to be over-predicted. The unsteady effects using the unsteady flamelets have also been studied to assess the effects of jet velocity on flame characteristics and it has been observed that the unsteady flamelet results are similar to those obtained using the steady flamelet model. The effects of fuel variation on the flame structure are captured reasonably well by flamelet model.
Effect of Flow Pulsation on Transport and Secondary Atomization of a Polydisperse Evaporating Spray
Authors: Mahapatra Pallab S. , Panchagnula Mahesh V. , Mukhopadhyay Achintya
Published: February 2015

In the present work a 1D plug flow evaporator has been considered to study the evaporation, atomization and transport of polydisperse droplets in a pulsating air stream. The pulsation in the air flow is very common in the real combustor due to the thermo acoustic instabilities. Population balance modeling approach is used to study the continuous evaporation and atomization process. An Eulerian-Eulerian multiphase framework is used to capture the polydispersity of the system. For the evaporation the fixed drop size methodology of the D2 law has been used whereas, for the atomization the conservation of mass has been considered during the breakage. The objective of this work is to study the pulsation frequency on the dispersion of droplets without and with presence of the evaporation and atomization rate. From the results, clustering of particles in different locations has been identified. The variation of Sauter Mean Diameter (SMD) is presented and the non-linear behaviour has been identified in the process.
An Investigation in to the Rotordynamics Behavior of Mechanically Coupled Turbo Expander
Authors: Kannan Balaji , Vaidyanathan Krishnamurthy , Pithamber Kiran , Mahapatra Suvendu
Published: February 2015

Considerable amount of mathematical modeling backed by extensive experimental investigations have gone in to the study of the rotordynamics behavior of high speed turbo expanders. These investigations revolve predominantly around the linear & non-linear aspects of hydrodynamic bearings that support these rotating elements. Further, these expanders are not mechanically coupled to the prime mover and hence the impact of lateral vibrations imposed by the interfacing assemblies downstream is not a concern.

However, when the expander is mechanically coupled to a prime mover, say by means of gears, lateral vibrations resulting from the interfacing system is going to have a pronounced effect on the rotordynamics behavior of this system. It is of paramount importance that we account for the stiffness & damping properties of the interface components in order to accurately predict the rotordynamics behavior of the expander.

An attempt is being made by the authors to develop an expander and bearing system along with a high speed, multi stage reduction gear box, to understand the impact of lateral vibrations due to mechanical coupling of the expander.
Whole-Genome Sequencing Analysis of Quorum-Sensing Aeromonas hydrophila Strain M023 from Freshwater
Authors: Tan Wen-Si , Yin Wai-Fong , Chang Chien-Yi , Chan Kok-Gan
Published: February 2015

Aeromonas hydrophila
is a well-known waterborne pathogen that recently was found to infect humans. Here, we report the draft genome of a freshwater isolate from a Malaysian waterfall, A. hydrophila strain M023, which portrays
N
-acylhomoserine lactone-dependent quorum sensing.
Murine Coronavirus Ubiquitin-Like Domain Is Important for Papain-Like Protease Stability and Viral Pathogenesis
Authors: Mielech Anna M. , Deng Xufang , Chen Yafang , Kindler Eveline , Wheeler Dorthea L. , Mesecar Andrew D. , Thiel Volker , Perlman Stanley , Baker Susan C.
Published: February 2015

Ubiquitin-like domains (Ubls) now are recognized as common elements adjacent to viral and cellular proteases; however, their function is unclear. Structural studies of the papain-like protease (PLP) domains of coronaviruses (CoVs) revealed an adjacent Ubl domain in severe acute respiratory syndrome CoV, Middle East respiratory syndrome CoV, and the murine CoV, mouse hepatitis virus (MHV). Here, we tested the effect of altering the Ubl adjacent to PLP2 of MHV on enzyme activity, viral replication, and pathogenesis. Using deletion and substitution approaches, we identified sites within the Ubl domain, residues 785 to 787 of nonstructural protein 3, which negatively affect protease activity, and valine residues 785 and 787, which negatively affect deubiquitinating activity. Using reverse genetics, we engineered Ubl mutant viruses and found that AM2 (V787S) and AM3 (V785S) viruses replicate efficiently at 37°C but generate smaller plaques than wild-type (WT) virus, and AM2 is defective for replication at higher temperatures. To evaluate the effect of the mutation on protease activity, we purified WT and Ubl mutant PLP2 and found that the proteases exhibit similar specific activities at 25°C. However, the thermal stability of the Ubl mutant PLP2 was significantly reduced at 30°C, thereby reducing the total enzymatic activity. To determine if the destabilizing mutation affects viral pathogenesis, we infected C57BL/6 mice with WT or AM2 virus and found that the mutant virus is highly attenuated, yet it replicates sufficiently to elicit protective immunity. These studies revealed that modulating the Ubl domain adjacent to the PLP reduces protease stability and viral pathogenesis, revealing a novel approach to coronavirus attenuation.

IMPORTANCE
Introducing mutations into a protein or virus can have either direct or indirect effects on function. We asked if changes in the Ubl domain, a conserved domain adjacent to the coronavirus papain-like protease, altered the viral protease activity or affected viral replication or pathogenesis. Our studies using purified wild-type and Ubl mutant proteases revealed that mutations in the viral Ubl domain destabilize and inactivate the adjacent viral protease. Furthermore, we show that a CoV encoding the mutant Ubl domain is unable to replicate at high temperature or cause lethal disease in mice. Our results identify the coronavirus Ubl domain as a novel modulator of viral protease stability and reveal manipulating the Ubl domain as a new approach for attenuating coronavirus replication and pathogenesis.
Regional setting and deposit geology of the Golden Sunlight Mine
Authors: Oyer Nancy , Childs John , Mahoney J. Brian
Published: February 2015

The Barrick Golden Sunlight Mine (GSM) in Whitehall, Montana, is an industry leader in safe, responsible resource extraction. With more than 3 million ounces of gold poured since 1983, and current proven and probable reserves of 318,000 ounces of gold, GSM is the largest gold producer in Montana. The gold-silver deposit is localized in a hydrothermal breccia pipe related to Late Cretaceous latite porphyry magmatism hosted by the Mesoproterozoic Belt Supergroup, and is influenced by younger cross-cutting faults and fracture systems. The deposit has been mined by both underground and open pit methods, and the current open pit operation was recently permitted for expansion. The mill and tailings operations practice efficient and environmentally responsible resource recovery by processing ore from historical tailings and dumps from around the state in addition to ore from the Golden Sunlight property. This trip will explore the complex geologic and tectonic controls on mineralization and review how GSM has addressed the technical challenges of mining, milling, and reclamation.
Hip arthritis presenting as knee pain
Authors: Lam Stephen , Amies Victoria
Published: February 2015

A 68-year-old man with a history of left total knee replacement presented to his general practitioner with left knee pain. He reported pain onset after a fall in the garden. An X-ray of the knee was arranged but showed no abnormality to explain the pain. He was treated with simple analgesia. However, he reattended with the same knee pain. A further X-ray of the knee was requested, but again showed no abnormality. On his fourth presentation in 6 months, a further musculoskeletal examination was undertaken. This time the hip was also examined and showed that maximal pain was in fact on rotation of the hip joint. A subsequent X-ray of the hip showed severe osteoarthritis of the left hip with complete joint space loss and flattening of the femoral head. The patient was referred to an orthopaedic surgeon for a left hip replacement.
Haemorrhagic rupture of hepatic simple cysts
Authors: Simon Tiarah , Bakker Ilsalien S , Penninga Luit , Nellensteijn David R
Published: February 2015

Haemorrhagic rupture is a life-threatening complication of a hepatic simple cyst. A 63-year-old man presented with severe acute abdominal pain and a massive haemoperitoneum resulting from haemorrhagic rupture of a large hepatic cyst. The haemorrhagic rupture was aggravated by an overdose of vitamin K-antagonist treatment. CT scans revealed a large hepatic simple cyst. The patient was successfully treated conservatively with resuscitation, transfusion therapy and administration of coagulation agents. To date, there is no clear evidence regarding optimal treatment of haemorrhagic hepatic cyst rupture. The risk of recurrent bleeding from the haemorrhagic hepatic simple cyst, and the need for final treatment to avoid rebleeding either by percutaneous sclerotherapy, endovascular embolisation, surgical cyst resection, or surgical deroofing, is discussed.
Tacrolimus or infliximab for severe ulcerative colitis: short-term and long-term data from a retrospective observational study
Authors: Minami Naoki , Yoshino Takuya , Matsuura Minoru , Koshikawa Yorimitsu , Yamada Satoshi , Toyonaga Takahiko , Madian Ali , Honzawa Yusuke , Nakase Hiroshi
Published: February 2015

Objective

Treatment of severe ulcerative colitis (UC) is challenging. Although the efficacy of tacrolimus (TAC) and infliximab (IFX) have been evaluated in patients with severe UC, the safety and efficacy levels of sequential therapies (TAC→IFX/IFX→TAC) in these patients remain unclear. The aim of this study was to assess short-term and long-term outcomes in patients with severe UC treated with TAC and IFX.

Methods

From October 2001 to February 2014, 29 patients with consecutive severe UC treated with TAC or IFX were retrospectively evaluated. Median follow-up duration was 27 months (range 0.5–118 months). The primary end point was short-term outcomes at 8 weeks after induction of TAC (TAC group, n=22) or IFX (IFX group, n=7). The secondary end point included long-term outcomes and colectomy-free survival. The clinical response was evaluated based on a partial Mayo score.

Results

The clinical remission (CR) rate at 8 weeks in the TAC and IFX groups was 63.6% and 71.4%, respectively. In 13 of the 29 patients (10 in the TAC group, 3 in the IFX group), sequential therapies were used in their clinical courses. In 9 of these 13 patients (6 in the TAC group, 3 in the IFX group), CR was achieved and maintained by sequential therapies. Overall cumulative colectomy-free survival was 79.3% at 118 months.

Conclusions

TAC and IFX had similar effects on remission induction in patients with severely active UC. Sequential therapies could rescue patients with UC who failed initial treatment with TAC or IFX. In clinical practice, sequential therapies might be deliberately performed.
Mass spectrometric analysis of unknown haemoglobin fractions identified by high-performance liquid chromatography in an antenatal screening programme
Authors: Griffin M , Eyre J , Dack S , Wright J
Published: February 2015

Aims

The majority of haematology laboratories use automated high-performance liquid chromatography (HPLC) as a primary method in the screening of samples for haemoglobin variants and thalassaemia. HPLC detects adducted fractions, such as HbA1C and other peaks of unknown significance. The National Health Service (NHS) Sickle and Thalassaemia Screening Programme does not mandate further assessment of these unknown peaks, but their presence may cause concern or precipitate detailed investigations. Mass spectrometry (MS) is being increasingly used in NHS Laboratories and is an effective method of characterising variant haemoglobins.

Method

Antenatal blood samples accepted for NHS Sickle and Thalassaemia Screening Programme from 2005 to 2013 were assessed. Those samples with unidentified peaks on HPLC were further analysed by Liquid chromatography tandem MS (LCMSMS).

Results

58 493 samples were processed. 966 (1.6%) significant haemoglobinopathies were identified. 68 patients (0.11%) were found to have unidentified peaks on HPLC. α chain variants: two were hyperunstable α variants, Hb Adana and Hb H/Constant Spring. The patient with HbH/Constant Spring required transfusion during pregnancy. Other abnormalities include 24 unstable α chain variants of minimal clinical significance and 17 α chain variants of no clinical significance. The frequency of β chain abnormalities was lower, with 10 patients having an insignificant β chain variant, 4 mildly unstable β chain variants (2 of whom had increased oxygen affinity) and 4 with variants associated with increased oxygen affinity.

Conclusions

The prevalence of unidentified variants on automated HPLC within our population is 0.1%. LCMSMS is an effective technique to assist in the characterisation of unknown haemoglobin variants. α chain variants of limited clinical significance were the most commonly detected abnormality.
Does increased air humidity affect stomatal morphology and functioning in hybrid aspen?
Authors: Niglas Aigar , Alber Meeli , Suur Kristi , Jasińska Anna K. , Kupper Priit , Sellin Arne
Published: February 2015

The study investigated the effects of exposure to increased relative air humidity (RH) on stomatal morphology and sensitivity to stomata closure inducing stimulus (low RH) in hybrid aspen (Populus tremula L. × P. tremuloides Michx.) coppice growing in field conditions. Artificially elevated RH reduced air vapour pressure deficit by 5%–10% and altered stomatal sensitivity; trees grown under high RH exhibited stronger stomatal response to decreasing air humidity. We found no difference in mean stomatal pore length between treatments and a small decline in stomatal density under humidification. The lack of correlation between stomatal sensitivity and morphological traits suggests that stomatal sensitivity was unaffected by stomatal morphology. In light of rising atmospheric humidity predicted for high latitudes, strict stomatal control over water loss might be beneficial for trees if drought events become more frequent in the future. However, our experiment revealed that about two-thirds of the leaf-to-air vapour pressure difference (VPDL) response curves demonstrated the opposite pattern, i.e., stomatal opening in response to increasing VPDL. Strict stomatal regulation is probably not beneficial to fast-growing aspen coppice under low RH, as this trait may restrict their carbon gain and growth rate.
Evaporation phenomena in f(T) gravity
Authors: Houndjo M.J.S. , Momeni D. , Myrzakulov R. , Rodrigues M.E.
Published: February 2015

We formulate evaporation phenomena in a generic model of generalized teleparallel gravity in Weitzenbock space–time with a diagonal and nondiagonal tetrad basis. We also perform perturbation analysis around the constant torsion scalar solution called the Nariai space–time, which is an exact solution of the field equations as the limiting case of the Schwarzschild – de Sitter space–time and in the limit where two black holes and their cosmological horizons coincide. By a carefully analysis of the horizon perturbation equation, we show that (anti)evaporation cannot happen if we use a diagonal tetrad basis. This result implies that a typical black hole in any generic form of generalized teleparallel gravity is frozen in its initial state if we use diagonal tetrads, but in the case of nondiagonal tetrads the analysis is completely different. With a suitable nontrivial nondiagonal tetrad basis we investigate the linear stability of the model under simultaneous perturbations of the metric and torsion. We observe that in spite of the diagonal case, both evaporation and antievaporation can happen. These phenomena depend on the initial phase of the horizon perturbation. In the first mode, when we restrict ourselves to the first lower modes (anti)evaporation takes place. So, in the nondiagonal case, the physical phenomena are reasonable. This is an important advantage of using nondiagonal tetrads instead of diagonal ones. We also see that this is a universal feature, completely independent from the form of the model.