bluuebunny/crossref_metadata_2025 huggingface dataset:
SOFC Stack Model for Integration Into a Hybrid System: Stack Response to Control Variables
Authors: Whiston Michael M. , Bilec Melissa M. , Schaefer Laura A.
Published: February 2015

Due to the tight coupling of physical processes inside solid oxide fuel cells (SOFCs), efficient control of these devices depends largely on the proper pairing of controlled and manipulated variables. The present study investigates the uncontrolled, dynamic behavior of an SOFC stack that is intended for use in a hybrid SOFC-gas turbine (GT) system. A numerical fuel cell model is developed based on charge, species mass, energy, and momentum balances, and an equivalent circuit is used to combine the fuel cell's irreversibilities. The model is then verified on electrochemical, mass, and thermal timescales. The open-loop response of the average positive electrode-electrolyte-negative electrode (PEN) temperature, fuel utilization, and SOFC power to step changes in the inlet fuel flow rate, current density, and inlet air flow rate is simulated on different timescales. Results indicate that manipulating the current density is the quickest and most efficient way to change the SOFC power. Meanwhile, manipulating the fuel flow is found to be the most efficient way to change the fuel utilization. In future work, it is recommended that such control strategies be further analyzed and compared in the context of a complete SOFC-GT system model.
A Generalized Prediction Method for Rotordynamic Coefficients of Annular Gas Seals
Authors: Yan Xin , He Kun , Li Jun , Feng Zhenping
Published: February 2015

The improvement in rotordynamic performance of the annular gas seal requires efficient and accurate prediction methods of rotordynamic coefficients. Although the existed transient computational fluid dynamics (CFD) methods in published literature have excellent numerical accuracy, most of them face the challenge due to rotordynamic coefficients at every excitation frequency to be solved by a separate transient CFD prediction thus much time-consuming. In this paper, a generalized prediction method is proposed to address this difficulty. Based on the Laplace transform method, the solution procedures for the reaction force/motion equation of the annular gas seal are deduced. With the specified excitations (rotor motion), the rotordynamic coefficients at all excitation frequencies can be solved by only one or two transient CFD solutions. To verify the present generalized method, the rotordynamic coefficients of two typical hole-pattern seals are computed and compared to the available experimental data. The results show that the predicted rotordynamic coefficients are in good agreement with the experimental tests. Compared to the previous transient CFD methods, the computational time of the present generalized method is reduced significantly while the accuracy is still maintained.
Organic Rankine Cycle Power Systems: From the Concept to Current Technology, Applications, and an Outlook to the Future
Authors: Colonna Piero , Casati Emiliano , Trapp Carsten , Mathijssen Tiemo , Larjola Jaakko , Turunen-Saaresti Teemu , Uusitalo Antti
Published: February 2015

The cumulative global capacity of organic Rankine cycle (ORC) power systems for the conversion of renewable and waste thermal energy is undergoing a rapid growth and is estimated to be approx. 2000 MWe considering only installations that went into operation after 1995. The potential for the conversion of the thermal power coming from liquid-dominated geothermal reservoirs, waste heat from primary engines or industrial processes, biomass combustion, and concentrated solar radiation into electricity is arguably enormous. ORC technology is possibly the most flexible in terms of capacity and temperature level and is currently often the only applicable technology for the conversion of external thermal energy sources. In addition, ORC power systems are suitable for the cogeneration of heating and/or cooling, another advantage in the framework of distributed power generation. Related research and development is therefore very lively. These considerations motivated the effort documented in this article, aimed at providing consistent information about the evolution, state, and future of this power conversion technology. First, basic theoretical elements on the thermodynamic cycle, working fluid, and design aspects are illustrated, together with an evaluation of the advantages and disadvantages in comparison to competing technologies. An overview of the long history of the development of ORC power systems follows, in order to place the more recent evolution into perspective. Then, a compendium of the many aspects of the state of the art is illustrated: the solutions currently adopted in commercial plants and the main-stream applications, including information about exemplary installations. A classification and terminology for ORC power plants are proposed. An outlook on the many research and development activities is provided, whereby information on new high-impact applications, such as automotive heat recovery is included. Possible directions of future developments are highlighted, ranging from efforts targeting volume-produced stationary and mobile mini-ORC systems with a power output of few kWe, up to large MWe base-load ORC plants.
On Simple Design of Nonlinear Observers for Robust Stabilization of Nonlinear Systems
Authors: Hammer Jacob
Published: February 2015

Robust internal stabilization is a strong notion of stabilization, whereby stability is maintained regardless of small disturbances, noises, and uncertainties. In this paper, simple tools are developed for achieving robust internal stabilization of a rather large family of nonlinear systems. The main notion is that of a strict observer function, a function characterized by the following feature: subtracting a strict observer function from the differential equation of the controlled system results in an asymptotically stable differential equation. Strict observer functions are relatively easy to derive, and they directly yield robust asymptotic observers; the latter can be combined with robust state feedback controllers to achieve robust internal stabilization.
Improvement of Hydrodynamic Performance of a Multiphase Pump Using Design of Experiment Techniques
Authors: Kim Joon-Hyung , Lee Him-Chan , Kim Jin-Hyuk , Choi Young-Seok , Yoon Joon-Yong , Yoo Il-Soo , Choi Won-Chul
Published: February 2015

Multiphase pumps for offshore plants must perform at high pressure because they are installed on deep-sea floors to pressurize and transfer crude oil in oil wells. As the power for operating pumps should be supplied to deep sea floors using umbilicals, risers, and flow lines (URF), which involve a higher cost to operate pumps, the improvement of pump efficiency is strongly emphasized. In this study, a design optimization to improve the hydrodynamic performance of multiphase pumps for offshore plants was implemented. The design of experiment (DOE) techniques was used for organized design optimization. When DOE was performed, the performance of each test set was evaluated using the verified numerical analysis. In this way, the efficiency of the optimization was improved to save time and cost. The degree to which each design variable affects pump performance was evaluated using fractional factorial design, so that the design variables having a strong effect were selected based on the result. Finally, the optimized model indicating a higher performance level than the base model was generated by design optimization using the response surface method (RSM). How the performance was improved was also analyzed by comparing the internal flow fields of the base model with the optimized model. It was found that the nonuniform flow components observed on the base model were sharply suppressed in the optimized model. In addition, due to the increase of the pressure performance of the optimized model, the volume of air was reduced; therefore, the optimized model showed less energy loss than the base model.
Design of a Portable Compliant Device for Estimating the Failure-Load of Mesoscale Cemented Sand Specimens
Authors: Bhargav Santosh D. B. , Kandasami Ramesh K. , Murthy Tejas G. , Ananthasuresh G. K.
Published: February 2015

In this paper, we present the design and development of a portable, hand-operated composite compliant mechanism for estimating the failure-load of cm-sized stiff objects whose stiffness is of the order of 10 s of kN/m. The motivation for the design comes from the need to estimate the failure-load of mesoscale cemented sand specimens in situ, which is not possible with traditional devices used for large specimens or very small specimens. The composite compliant device, developed in this work, consists of two compliant mechanisms: a force-amplifying compliant mechanism (FaCM) to amplify sufficiently the force exerted by hand in order to break the specimen and a displacement-amplifying compliant mechanism (DaCM) to enable measurement of the force using a proximity sensor. The two mechanisms are designed using the selection-maps technique to amplify the force up to 100 N by about a factor of 3 and measure the force with a resolution of 15 mN. The composite device, made using a FaCM, a DaCM, and a Hall effect-based proximity sensor, was tested on mesoscale cemented sand specimens that were 10 mm in diameter and 20 mm in length. The results are compared with those of a large commercial instrument. Through the experiments, it was observed that the failure-load of the cemented sand specimens varied from 0.95 N to 24.33 N, depending on the percentage of cementation and curing period. The estimation of the failure-load using the compliant device was found to be within 1.7% of the measurements obtained using the commercial instrument and thus validating the design. The details of the design, prototyping, specimen preparation, testing, and the results comprise the paper.
Effect of Operating Pressure and Dent Depth on Burst Strength of NPS30 Linepipe With Dent–Crack Defect
Authors: Ghaednia Hossein , Das Sreekanta , Wang Rick , Kania Richard
Published: February 2015

Buried linepipe can be exposed to various external interferences and corrosive environment and as a result, damage in the form of dent or corrosion or crack or gouge or combination of any of these damages can form in the pipe wall. A defect combining dent and crack, often known as dent–crack defect, which may lead to a rupture or leak in the pipe wall and hence, the pipeline operator becomes concerned about the performance and safety of the pipeline. A research was recently completed at the Centre for Engineering Research in Pipelines (CERP), University of Windsor to study the influence of dent depth and operating line pressure on the pressure capacity (burst strength) of 30 in. diameter and X70 grade linepipe. This study found that the dent depth of 12% with crack depth of 4 mm or more can reduce the pressure capacity by 38%. This paper discusses the test specimens, test setup, test procedure, test results, and data obtained from finite element analyses.
Design of a Miniaturized Pneumatic Vibration Isolator With High-Static-Low-Dynamic Stiffness
Authors: Shan Yuhu , Wu Wenjiang , Chen Xuedong
Published: February 2015

In the ultraprecision vibration isolation systems, it is desirable for the isolator to have a larger load bearing capacity and a broader isolation bandwidth simultaneously. Generally, pneumatic spring can bear large load and achieve relatively low natural frequency by enlarging its chamber volume. However, the oversized isolator is inconvenient to use and might cause instability. To reduce the size, a miniaturized pneumatic vibration isolator (MPVI) with high-static-low-dynamic stiffness (HSLDS) is developed in this paper. The volume of proposed isolator is minimized by a compact structure design that combines two magnetic rings in parallel with the pneumatic spring. The two magnetic rings are arranged in the repulsive configuration and can be mounted into the chamber to provide the negative stiffness. Then dynamic model of the developed MPVI is built and the isolation performances are analyzed. Finally, experiments on the isolator with and without the magnetic rings are conducted. The final experimental results are consistent with the dynamical model and verify the effectiveness of the developed vibration isolator.
Biomass Gasification Hot Gas Cleanup for Power Generation
Authors: Wiant Benjamin C. , Bachovchin Dennis M. , Horazak Dennis A. , Onischak Michael , Carty Ronald H. , Ruel Roy H.
Published: February 2015

In support of the U.S. Department of Energy’s Biomass Power Program, a Westinghouse Electric led team consisting of the Institute of Gas Technology, Gilbert/Commonwealth, and the Pacific International Center for High Technology Research, is conducting a 30-month research and development program to provide validation of hot gas cleanup technology with a pressurized fluidized bed, air-blown, biomass gasifier for operation of a combustion turbine. This paper discusses the gasification and hot gas cleanup processes, scope of work and approach, and the program’s status.
Evaluation of Repowering Cycles
Authors: Riekert Louis A.
Published: February 2015

There are three primary methods by which an aging steam electric unit can be repowered by incorporating a gas turbine-generator. These are: heat recovery steam generator repowering, Feedwater Heater repowering, and Windbox repowering. Evaluation of these options can be very difficult due to the fact that the initial capital cost may be the smallest cost. The present worth of future fuel and maintenance costs can far outweigh the initial cost. An additional complexity is the fact that the repowered unit may have the best unit heat rate within the system. It will certainly be improved, which means the capacity factor will be increased. As the capacity factor increases, the cost of fuel becomes more significant. For a base loaded fossil unit, the cost of fuel is the largest single annual cost. Prediction of the future capacity factor is complex, involving many variables and uncertainties. Selection of the best method requires an evaluation of future energy demand and currently incurred capital costs as well as future fuel and maintenance costs. Determination of an optimum balance between present and future costs has always been the problem of the utility planner.

The intent of this paper is to outline an evaluation method to determine the most suitable repowering option. Comments regarding each option will be made. In some cases, a selection can be made by intuition or by observing the obvious. In other cases, the selection will not be obvious. The utility will always benefit from the execution of a well thought out evaluation plan. Following an orderly procedure will enhance the thought process. In addition, a documented procedure will be available for re-evaluation when changes occur and will always provide documentation for future reference.
The use of the stationary phase method as a mathematical tool to determine the path of optical beams
Authors: Carvalho Silvânia A. , De Leo Stefano
Published: February 2015

We use the stationary phase method to determine the paths of optical beams that propagate through a dielectric block. In the presence of partial internal reflection, we recover the geometrical result obtained by using Snell's law. For total internal reflection, the stationary phase method overreaches Snell's law, predicting the Goos-Hänchen shift.
Impact behavior of a superball
Authors: Cross Rod
Published: February 2015

When a superball is incident with backspin on a horizontal surface, at an angle near the normal, it bounces backwards and with a reversal in the spin direction. The effect is less noticeable with other balls, which may bounce with reduced spin and without a reversal in the spin direction. The outcome depends on the friction force acting on the ball. Measurements with several different rubber balls are presented showing that the time history of the friction force, the resulting tangential impulse, and the resulting tangential coefficient of restitution all depend on both the coefficient of sliding friction and the ratio of the tangential vibration period to the impact duration of the ball. Grip and slip phases of the bounce are identified visually by allowing the ball to impact on chalk lines drawn on a blackboard, and by video-recording the bounce of a rectangular block of rubber.
Thermodynamic time asymmetry and the Boltzmann equation
Authors: Boozer A. D.
Published: February 2015

An important result of statistical mechanics is the Boltzmann equation, which describes the evolution of the velocity distribution of a gas towards the equilibrium Maxwell distribution. We introduce the Boltzmann equation by considering a dynamical model of a two-dimensional gas consisting of hard disks. We derive the Boltzmann equation for the model and compare the behavior predicted by this equation against the actual behavior of the system as observed in computer simulations. A puzzling feature of the Boltzmann equation is that although the dynamical laws governing the gas are time-reversal invariant, the behavior predicted by the Boltzmann equation is time asymmetric. We show that this time asymmetry arises from assumptions made in the derivation of the Boltzmann equation, and we use computer simulations of the model system to investigate the circumstances under which these assumptions hold.
Web applet for predicting structure and thermodynamics of complex fluids
Authors: Popp Theodore R. , Hollingshead Kyle B. , Truskett Thomas M.
Published: February 2015

Based on a recently introduced analytical strategy [Hollingshead et al., J. Chem. Phys. 139, 161102 (2013)], we present a web applet that can quickly and semi-quantitatively estimate the equilibrium radial distribution function and related thermodynamic properties of a fluid from knowledge of its pair interaction. We describe the applet's features and present two (of many possible) examples of how it can be used to illustrate concepts of interest for introductory statistical mechanics courses: the transition from ideal gas-like behavior to correlated-liquid behavior with increasing density, and the tradeoff between dominant length scales with changing temperature in a system with ramp-shaped repulsions. The latter type of interaction qualitatively captures distinctive thermodynamic properties of liquid water, because its energetic bias toward locally open structures mimics that of water's hydrogen-bond network.
Wave functions of elliptical quantum dots in a magnetic field
Authors: Zhou Daming , Lorke Axel
Published: February 2015

We use the variational principle to obtain the wave functions of elliptical quantum dots under the influence of an external magnetic field. For the first excited states, whose wave functions have recently been mapped experimentally, we find a simple expression, based on a linear combination of the wave functions in the absence of a magnetic field. The results illustrate how a magnetic field breaks the x-y symmetry and mixes the corresponding eigenstates. The obtained eigenenergies agree well with those obtained by more involved analytical and numerical methods.
Interactive molecular dynamics
Authors: Schroeder Daniel V.
Published: February 2015

Physics students now have access to interactive molecular dynamics simulations that can model and animate the motions of hundreds of particles, such as noble gas atoms, that attract each other weakly at short distances but repel strongly when pressed together. Using these simulations, students can develop an understanding of forces and motions at the molecular scale, nonideal fluids, phases of matter, thermal equilibrium, nonequilibrium states, the Boltzmann distribution, the arrow of time, and much more. This article summarizes the basic features and capabilities of such a simulation, presents a variety of student exercises using it at the introductory and intermediate levels, and describes some enhancements that can further extend its uses. A working simulation code, in html5 and javascript for running within any modern Web browser, is provided as an online supplement.
The Simple Genetic Algorithm Approach for Optimization of Nesting of Sheet Metal Parts in Blanking Operation
Authors: Ramesh K. , Baskar N.
Published: February 2015

The two-dimensional (2D) cutting stock is a common problem arising in the sheet metal industries, lock industries, textile industries, etc. Here, the problem is to reduce the wastage in order to increase the profit. This problem is also called as the general 2D problem or NP hard problems. The choice of chromosome representation in genetic algorithm (GA) depends on the variables of the optimization problem being solved. The main objectives of the work are the maximum utilization of part in the sheet and also minimizing the wastage.
Improving Risk Governance for Adapting to Climate Change: Case from Shanghai
Authors: ZHENG Yan , XIE Xinlu
Published: February 2015

Decision-making under changing climate has become uncertain and complex, which brings great challenges to traditional risk governance process. Coastal areas in China have been highly urbanized with increasing population and physical assets during the past decades. Based on a simplified risk governance framework, a case of Chinese coastal megacity is evaluated with key functions of risk assessment, risk management, and risk communication. It finds that the case of "Comprehensive Coordination Centre" in Shanghai Fengxian District can play a positive role to improve effectiveness, efficiency, and accountability of risk governance in the Chinese context, especially a potential to reduce "organized irresponsibility" and "systematic risks". Adaptive and integrated risk governance can be improved from policy experiments and experience learnt from implementation. This paper concludes that the innovation in the existing disaster risk reduction system will promote the ability of adaptation to climate change in the long run.
Collective Algorithms for Multiported Torus Networks
Authors: Sack Paul , Gropp William
Published: February 2015

Modern supercomputers with torus networks allow each node to simultaneously pass messages on all of its links. However, most collective algorithms are designed to only use one link at a time. In this work, we present novel multiported algorithms for the scatter, gather, all-gather, and reduce-scatter operations. Our algorithms can be combined to create multiported reduce, all-reduce, and broadcast algorithms. Several of these algorithms involve a new technique where we relax the MPI message-ordering constraints to achieve high performance and restore the correctordering using an additional stage of redundant communication.

According to our models, on an
n
-dimensional torus, our algorithms should allow for nearly a 2
n
-fold improvement in communication performance compared to known, single-ported torus algorithms. In practice, we have achieved nearly 6x better performance on a 32k-node 3-dimensional torus.
Power Management of Extreme-Scale Networks with On/Off Links in Runtime Systems
Authors: Totoni Ehsan , Jain Nikhil , Kale Laxmikant V.
Published: February 2015

Networks are among major power consumers in large-scale parallel systems. During execution of common parallel applications, a sizeable fraction of the links in the high-radix interconnects are either never used or are underutilized. We propose a runtime system based adaptive approach to turn off unused links, which has various advantages over the previously proposed hardware and compiler based approaches. We discuss why the runtime system is the best system component to accomplish this task, and test the effectiveness of our approach using real applications (including NAMD, MILC), and application benchmarks (including NAS Parallel Benchmarks, Stencil). These codes are simulated on representative topologies such as 6-D Torus and multilevel directly connected network (similar to IBM PERCS in Power 775 and Dragonfly in Cray Aries). For common applications with near-neighbor communication pattern, our approach can save up to 20% of total machine's power and energy, without any performance penalty.
High-Performance and Scalable GPU Graph Traversal
Authors: Merrill Duane , Garland Michael , Grimshaw Andrew
Published: February 2015

Breadth-First Search (BFS) is a core primitive for graph traversal and a basis for many higher-level graph analysis algorithms. It is also representative of a class of parallel computations whose memory accesses and work distribution are both irregular and data dependent. Recent work has demonstrated the plausibility of GPU sparse graph traversal, but has tended to focus on asymptotically inefficient algorithms that perform poorly on graphs with nontrivial diameter.

We present a BFS parallelization focused on fine-grained task management constructed from efficient prefix sum computations that achieves an asymptotically optimal O(|V| + |E|) gd work complexity. Our implementation delivers excellent performance on diverse graphs, achieving traversal rates in excess of 3.3 billion and 8.3 billion traversed edges per second using single- and quad-GPU configurations, respectively. This level of performance is several times faster than state-of-the-art implementations on both CPU and GPU platforms.
Upcoming SIGWEB supported conferences
Authors: Samuel Hamman
Published: February 2015

The Special Interest Group on Hypertext and the Web, SIGWEB was created in 1989 to support the community participating in the annual ACM Hypertext Conference. Now in its third decade, SIGWEB has grown considerably and now sponsors five annual conferences of different sizes and covering a wide range of topics. SIGWEB supports several specialized conferences, short courses, and workshops, as well as the Annual Hypertext Conference. SIGWEB sponsored conferences focus on timely topics in applied and computational hypertext and Web disciplines and provide a place for members and the entire applied Hypermedia and Web community to exchange ideas and to meet with and expand their network of colleagues. In this article, we provide a brief overview of SIGWEB sponsored conferences, in addition to events that are in cooperation with SIGWEB.
Visual cryptography on postage stamps
Authors: Bender Andreas O.
Published: February 2015

Some national post offices offer postage stamps showing an image chosen by the customer, but in at least one case, an image was refused for political reasons. Visual cryptography was used to get the post office to produce two stamps showing images which are closely related to the rejected image. They look like random graphic designs, but the original image appears when the two graphic designs are held one on top of the other and lit from the back.
Usability versus privacy instead of usable privacy
Authors: Gerber Paul , Volkamer Melanie , Renaud Karen
Published: February 2015

A smartphone is an indispensible device that also holds a great deal of personal and private data. Contact details, party or holiday photos and emails --- all carried around in our pockets and easily lost. On Android, the most widely-used smartphone operating system, access to this data is regulated by permissions. Apps request these permissions at installation, and they ideally only ask for permission to access data they really need to carry out their functions. The user is expected to check, and grant, requested permissions before installing the app. Their privacy can potentially be violated if they fail to check the permissions carefully. In June 2014 Google changed the Android permission screen, perhaps attempting to improve its usability. Does this mean that all is well in the Android eco-system, or was this update a retrograde move? This article discusses the new permission screen and its possible implications for smartphone owner privacy.
Effect of Salinity on Biomass Yield and Physiological and Stem-Root Anatomical Characteristics of Purslane (Portulaca oleraceaL.) Accessions
Authors: Alam Md. Amirul , Juraimi Abdul Shukor , Rafii M. Y. , Abdul Hamid Azizah
Published: February 2015

13 selected purslane accessions were subjected to five salinity levels 0, 8, 16, 24, and 32 dS m−1. Salinity effect was evaluated on the basis of biomass yield reduction, physiological attributes, and stem-root anatomical changes. Aggravated salinity stress caused significant (P<0.05) reduction in all measured parameters and the highest salinity showed more detrimental effect compared to control as well as lower salinity levels. The fresh and dry matter production was found to increase in Ac1, Ac9, and Ac13 from lower to higher salinity levels but others were badly affected. Considering salinity effect on purslane physiology, increase in chlorophyll content was seen in Ac2, Ac4, Ac6, and Ac8 at 16 dS m−1salinity, whereas Ac4, Ac9, and Ac12 showed increased photosynthesis at the same salinity levels compared to control. Anatomically, stem cortical tissues of Ac5, Ac9, and Ac12 were unaffected at control and 8 dS m−1salinity but root cortical tissues did not show any significant damage except a bit enlargement in Ac12 and Ac13. A dendrogram was constructed by UPGMA based on biomass yield and physiological traits where all 13 accessions were grouped into 5 clusters proving greater diversity among them. The 3-dimensional principal component analysis (PCA) has also confirmed the output of grouping from cluster analysis. Overall, salinity stressed among all 13 purslane accessions considering biomass production, physiological growth, and anatomical development Ac9 was the best salt-tolerant purslane accession and Ac13 was the most affected accession.
A Pilot Study: The Efficacy of Virgin Coconut Oil as Ocular Rewetting Agent on Rabbit Eyes
Authors: Mutalib Haliza Abdul , Kaur Sharanjeet , Ghazali Ahmad Rohi , Chinn Hooi Ng , Safie Nor Hasanah
Published: February 2015

Purpose. An open-label pilot study of virgin coconut oil (VCO) was conducted to determine the safety of the agent as ocular rewetting eye drops on rabbits.Methods. Efficacy of the VCO was assessed by measuring NIBUT, anterior eye assessment, corneal staining, pH, and Schirmer value before instillation and at 30 min, 60 min, and two weeks after instillation. Friedman test was used to analyse any changes in all the measurable variables over the period of time.Results. Only conjunctival redness with instillation of saline agent showed significant difference over the period of time (P<0.05). However, further statistical analysis had shown no significant difference at 30 min, 60 min, and two weeks compared to initial measurement (P>0.05). There were no changes in the NIBUT, limbal redness, palpebral conjunctiva redness, corneal staining, pH, and Schirmer value over the period of time for each agent (P>0.05).Conclusion. VCO acts as safe rewetting eye drops as it has shown no significant difference in the measurable parameter compared to commercial brand eye drops and saline. These study data suggest that VCO is safe to be used as ocular rewetting agent on human being.
Input-to-State Stability of Stochastic Memristive Neural Networks with Time-Varying Delay
Authors: Lou Xu Y. , Ye Qian
Published: February 2015

This paper is concerned with the input-to-state stability problem of a class of memristive neural networks. We consider the neural networks that take into account both the stochastic effects and time-varying delay, and introduce the notions of meansquare exponential input-to-state stability. Using the stochastic analysis theory and Itô formula for stochastic differential equations, we establish sufficient conditions for both mean-square exponential input-to-state stability and mean-square exponential stability. Numerical simulations are also provided to demonstrate the theoretical results.
A Hybrid Recommender System Based on User-Recommender Interaction
Authors: Zhang Heng-Ru , Min Fan , He Xu , Xu Yuan-Yuan
Published: February 2015

Recommender systems are used to make recommendations about products, information, or services for users. Most existing recommender systems implicitly assume one particular type of user behavior. However, they seldom consider user-recommender interactive scenarios in real-world environments. In this paper, we propose a hybrid recommender system based on user-recommender interaction and evaluate its performance with recall and diversity metrics. First, we define the user-recommender interaction. The recommender system accepts user request, recommendsNitems to the user, and records user choice. If some of these items favor the user, she will select one to browse and continue to use recommender system, until none of the recommended items favors her. Second, we propose a hybrid recommender system combining random andk-nearest neighbor algorithms. Third, we redefine the recall and diversity metrics based on the new scenario to evaluate the recommender system. Experiments results on the well-known MovieLens dataset show that the hybrid algorithm is more effective than nonhybrid ones.
Optical Properties of Spin-Coated TiO2Antireflection Films on Textured Single-Crystalline Silicon Substrates
Authors: Watanabe Ryosuke , Eguchi Yohei , Yamada Takuya , Saito Yoji
Published: February 2015

Antireflection coating (ARC) prepared by a wet process is beneficial for low cost fabrication of photovoltaic cells. In this study, we investigated optical properties and morphologies of spin-coated TiO2ARCs on alkaline textured single-crystalline silicon wafers. Reflectance spectra of the spin-coated ARCs on alkaline textured silicon wafers exhibit no interferences and low reflectance values in the entire visible range. We modeled the structures of the spin-coated films for ray tracing numerical calculation and compared numerically calculated reflectance spectra with the experimental results. This is the first report to clarify the novel optical properties experimentally and theoretically. Optical properties of the spin-coated ARCs without interference are due to the fractional nonuniformity of the thickness of the spin-coated ARCs that cancels out the interference of the incident light.
High-Frequency Dynamic Analysis of Plates in Thermal Environments Based on Energy Finite Element Method
Authors: Wang Di , Xie Miaoxia , Li Yueming
Published: February 2015

The energy density governing equation to analyze the high-frequency dynamic behavior of plates in thermal environments is derived in this paper, in which the thermal effects are considered to change the membrane stress state and temperature dependent material properties of plates. Then the thermal effects on the energy reflection and transmission coefficients are dealt with hereof. Based on the above, an EFEM (energy finite element method) based approximate approach for the energy analysis of coupled plates under nonuniform thermal environments is proposed. The approach could be conducted by three steps: (1) thermal analysis, (2) thermal stress analysis, and (3) forming element matrixes, joint matrixes, and the whole EFEM formulation for the energy analysis. The same mesh model is used for all the three steps. The comparison between EFEM results and classical modal superposition method results of simply supported plates in various uniform thermal environments and coupled plates in nonuniform thermal environments demonstrated that the derived energy governing equation and the proposed approach described well the smooth time- and locally space-averaged energy density. It is found that the distributions and levels of energy density are affected by thermal effects, and the variation trends are related to exciting frequency.
Bioaccessible Antioxidants in Milk Fermented byBifidobacterium longumsubsp.longumStrains
Authors: Gagnon Mérilie , Savard Patricia , Rivière Audrey , LaPointe Gisèle , Roy Denis
Published: February 2015

Bifidobacterium longumsubsp.longumis among the dominant species of the human gastrointestinal microbiota and could thus have potential as probiotics. New targets such as antioxidant properties have interest for beneficial effects on health. The objective of this study was to evaluate the bioaccessibility of antioxidants in milk fermented by selectedB. longumsubsp.longumstrains duringin vitrodynamic digestion. The antioxidant capacity of cell extracts from 38 strains, of which 32 belong toB. longumsubsp.longum, was evaluated with the ORAC (oxygen radical absorbance capacity) method. On the basis of screening and gene sequence typing by multilocus locus sequence analysis (MLSA), five strains were chosen for fermenting reconstituted skim milk. Antioxidant capacity varied among the strains tested (P=0.0009). Two strains ofB. longumsubsp.longum(CUETM 172 and 171) showed significantly higher ORAC values than the other bifidobacteria strains. However, there does not appear to be a relationship between gene sequence types and antioxidant capacity. The milk fermented by each of the five strains selected (CUETM 268, 172, 245, 247, or PRO 16-10) did not have higher initial ORAC values compared to the nonfermented milk samples. However, higher bioaccessibility of antioxidants in fermented milk (175–358%) was observed during digestion.
An Unexpected Presentation of Haemoperitoneum in a Pregnant Woman
Authors: Arulpragasam Kaushalya , Atkinson Andrea , Epee-Bekima Mathias
Published: February 2015

In the majority of tertiary centres the Emergency Room or Assessment Unit is the gateway to the rest of the hospital. It is the location where critical decisions are formulated depending on whether a patient’s condition is serious enough to warrant admission and, at times, emergency surgery. On occasion this decision can be straightforward based solely on the patient’s presentation, observations, and basic investigations. This case highlights that although the decision and initial management may be apparent, often the diagnosis can be unexpected and that the diagnostic challenge is often outside the scope of a brief Emergency Room assessment. Corpus luteal cyst rupture is a common phenomenon but often not the cause of significant morbidity as it was in this case, especially in the absence of any associated risk factors.
Determination of the Degree of Degradation of Frying Rapeseed Oil Using Fourier-Transform Infrared Spectroscopy Combined with Partial Least-Squares Regression
Authors: Chen Jie Yu , Zhang Han , Ma Jinkui , Tuchiya Tomohiro , Miao Yelian
Published: February 2015

This rapid method for determining the degree of degradation of frying rapeseed oils uses Fourier-transform infrared (FTIR) spectroscopy combined with partial least-squares (PLS) regression. One hundred and fifty-six frying oil samples that degraded to different degrees by frying potatoes were scanned by an FTIR spectrometer using attenuated total reflectance (ATR). PLS regression with full cross validation was used for the prediction of acid value (AV) and total polar compounds (TPC) based on raw, first, and second derivative FTIR spectra (4000–650 cm−1). The precise calibration model based on the second derivative FTIR spectra shows that the coefficients of determination for calibration(R2)and standard errors of cross validation (SECV) were 0.99 and 0.16 mg KOH/g and 0.98 and 1.17% for AV and TPC, respectively. The accuracy of the calibration model, tested using the validation set, yielded standard errors of prediction (SEP) of 0.16 mg KOH/g and 1.10% for AV and TPC, respectively. Therefore, the degradation of frying oils can be accurately measured using FTIR spectroscopy combined with PLS regression.
Perceived Cause, Environmental Factors, and Consequences of Falls in Adults with Cerebral Palsy: A Preliminary Mixed Methods Study
Authors: Morgan Prue , McDonald Rachael , McGinley Jennifer
Published: February 2015

Objective. Describe perceived cause, environmental influences, and consequences of falls or near-falls in ambulant adults with cerebral palsy (CP).Methods. Adults with CP completed postal surveys and follow-up semistructured interviews. Surveys sought information on demographic data, self-nominated Gross Motor Function Classification Score (GMFCS-E&R), falls, and near-falls. Interviews gathered additional information on falls experiences, near-falls, and physical and psychosocial consequences.Results. Thirty-four adults with CP participated. Thirty-three participants reported at least one fall in the previous year. Twenty-six participants reported near-falls. Most commonly, falls occurred indoors, at home, and whilst engaged in nonhazardous ambulation. Adults with CP experienced adverse falls consequences, lower limb injuries predominant (37%), and descriptions of fear, embarrassment, powerlessness, and isolation.Discussion. Adults with CP may experience injurious falls. Further investigation into the impact of falls on health-related quality of life and effective remediation strategies is warranted to provide comprehensive falls prevention programs for this population.
International Student’s Challenge and Adjustment to College
Authors: Wu Hsiao-ping , Garza Esther , Guzman Norma
Published: February 2015

International students’ enrollment in higher education in the US has expanded considerably in the last decades. In this study, international students’ experiences were examined in academic and sociocultural settings. Through qualitative interviews, the findings revealed that international students deal with academic challenges, social isolation, and cultural adjustment. Specifically, academic challenges included communication with professors, classmates, and staff. Consequently, they have to deal with social isolation when engaging in different group activities. Culturally, they need to confront the different ways of thinking and doing in the US. In order to overcome these challenges, students have adopted resources that mainly are derived from the university to overcome these challenges. Thus, as demonstrated in this study, having a better understanding of these students’ academic challenges, university faculty and staff can recognize students’ needs and effectively offer supportive campus resources and services. The university needs to be prepared to meet students not only academically but also socially and culturally. This study also suggests that some preparations need to be made by the university that will embrace international students upon their arrival.
A Nonsingular Terminal Sliding Mode Approach Using Adaptive Disturbance Observer for Finite-Time Trajectory Tracking of MEMS Triaxial Vibratory Gyroscope
Authors: Wang Wei , Zhao Qing , Zhao Yuxin , Du Dongzhen
Published: February 2015

This paper develops a nonsingular terminal sliding mode controller (NTSMC) with adaptive disturbance observer (ADOB) for finite-time trajectory tracking of a MEMS triaxial vibratory gyroscope, which has parameter variations and external high-amplitude disturbance. A novel sliding mode controller with adaptive disturbance observer is designed to reconfigure the parameter variations and external high-amplitude disturbance and reduce the chattering phenomenon on the sliding surface greatly through setting the switching gain in control signal as a smaller value. The disturbance adaptive law is derived to guarantee the stability of the closed-loop adaptive control system via the Lyapunov criterion. The simulation results are performed to verify the effectiveness of the presented schemes.
Cardiac Function in a Long-Term Follow-Up Study of Moderate and Severe Porcine Model of Chronic Myocardial Infarction
Authors: de Jong Renate , van Hout Gerardus P. J. , Houtgraaf Jaco H. , Takashima S. , Pasterkamp Gerard , Hoefer Imo , Duckers Henricus J.
Published: February 2015

Background. Novel therapies need to be evaluated in a relevant large animal model that mimics the clinical course and treatment in a reasonable time frame. To reliably assess therapeutic efficacy, knowledge regarding the translational model and the course of disease is needed.Methods. Landrace pigs were subjected to a transient occlusion of the proximal left circumflex artery (LCx)(n=6)or mid-left anterior descending artery (LAD)(n=6)for 150 min. Cardiac function was evaluated before by 2D echocardiography or 3D echocardiography and pressure-volume loop analysis. At 12 weeks of follow-up the heart was excised for histological analysis and infarct size calculations.Results. Directly following AMI, LVEF was severely reduced compared to baseline in the LAD group-17.1±1.6%, P=0.009compared to only a moderate reduction in the LCx group-5.9±1.5%, P=0.02and this effect remained unchanged during 12 weeks of follow-up.Conclusion. Two models of chronic MI, representative for different patient groups, can reproducibly be created through clinically relevant ischemia-reperfusion of the mid-LAD and proximal LCx.
Prediction of Antimicrobial Peptides Based on Sequence Alignment and Support Vector Machine-Pairwise Algorithm Utilizing LZ-Complexity
Authors: Ng Xin Yi , Rosdi Bakhtiar Affendi , Shahrudin Shahriza
Published: February 2015

This study concerns an attempt to establish a new method for predicting antimicrobial peptides (AMPs) which are important to the immune system. Recently, researchers are interested in designing alternative drugs based on AMPs because they have found that a large number of bacterial strains have become resistant to available antibiotics. However, researchers have encountered obstacles in the AMPs designing process as experiments to extract AMPs from protein sequences are costly and require a long set-up time. Therefore, a computational tool for AMPs prediction is needed to resolve this problem. In this study, an integrated algorithm is newly introduced to predict AMPs by integrating sequence alignment and support vector machine- (SVM-) LZ complexity pairwise algorithm. It was observed that, when all sequences in the training set are used, the sensitivity of the proposed algorithm is 95.28% in jackknife test and 87.59% in independent test, while the sensitivity obtained for jackknife test and independent test is 88.74% and 78.70%, respectively, when only the sequences that has less than 70% similarity are used. Applying the proposed algorithm may allow researchers to effectively predict AMPs from unknown protein peptide sequences with higher sensitivity.
The Construction of Support Vector Machine Classifier Using the Firefly Algorithm
Authors: Chao Chih-Feng , Horng Ming-Huwi
Published: February 2015

The setting of parameters in the support vector machines (SVMs) is very important with regard to its accuracy and efficiency. In this paper, we employ the firefly algorithm to train all parameters of the SVM simultaneously, including the penalty parameter, smoothness parameter, and Lagrangian multiplier. The proposed method is called the firefly-based SVM (firefly-SVM). This tool is not considered the feature selection, because the SVM, together with feature selection, is not suitable for the application in a multiclass classification, especially for the one-against-all multiclass SVM. In experiments, binary and multiclass classifications are explored. In the experiments on binary classification, ten of the benchmark data sets of the University of California, Irvine (UCI), machine learning repository are used; additionally the firefly-SVM is applied to the multiclass diagnosis of ultrasonic supraspinatus images. The classification performance of firefly-SVM is also compared to the original LIBSVM method associated with the grid search method and the particle swarm optimization based SVM (PSO-SVM). The experimental results advocate the use of firefly-SVM to classify pattern classifications for maximum accuracy.