bluuebunny/crossref_metadata_2025 huggingface dataset:
Improving Computational Fluid Dynamics Simulations for the Spallation Neutron Source Jet-Flow Target
Authors: Barbier C. , Dominguez-Ontiveros E.
Published: December 2016

A liquid mercury target is used at Oak Ridge National Laboratory’s (ORNL [1]) Spallation Neutron Source (SNS [2]) to generate neutrons. The mercury is flowing in a stainless steel containment vessel for neutron spallation, but also to cool the vessel itself. Computational Fluid Dynamics (CFD) simulations have been used to estimate the temperature and pressure fields needed for the thermal stress analysis. Because of the geometry complexity, the high turbulence number, and the computational time requirements, generating a quality mesh that can accurately capture the flow and heat transfer has always been a challenge. However, with today’s High Performance Computing (HPC) advances, larger and larger meshes can now be used and better accuracy can be achieved. In this study, two meshing methods were used for the SNS jet-flow target: automatic tetrahedral method (ANSYS meshing) and manual hexahedral meshing (ICEM-CFD). Both methods are compared in terms of quality, size, ease of generation, convergence, and user-friendliness. Both meshes were used with ANSYS-CFX to simulate the steady, Newtonian, single phase, isothermal, incompressible and turbulent flow in the target. The Shear Stress Transport (SST) k-ω model developed by Menter [3] was used for turbulence modeling. The accuracy of the CFD simulations are tested against experimental data presented in the current paper. An in-depth series of Particle Image Velocimetry (PIV) measurements performed on a “visual jet-flow target”, an acrylic replica target running with water, are presented in the paper. Since flow measurements in mercury are difficult, a water loop was built to investigate the flow in the target and a potential gas injection in the flow to mitigate the pressure wave [4]. A PIV system on a precise translation stage was setup on the water loop to perform detailed and accurate PIV measurements. Mean flow velocity fields were used to validate the CFD simulations. The paper concludes on the choice for mesh generation for future target analysis, and the path forward for CFD simulations for the future SNS targets.
Bio-Inspired Robotic Undulatory Stingray
Authors: Studebaker Emily , Ermlick William , Warner Rickey , Hart Brandon , Pandey Aanand , Smith Heather , Sienkiewicz Luke , Baillargeon Joseph , Roberson Nathan , An Jianyu , Gater Brittany , Feaster Jeffrey , Jung Sunghwan , Bayandor Javid
Published: December 2016

The purpose of this study was to investigate fin undulation as a form of locomotion. The analysis generated CFD simulations and models that identify characteristics that are known to indicate propulsive forces. A mechanical undulating fin was designed and built to experimentally validate these computational results. Comparing thrust data from the mechanical fin with the CFD results yielded qualitative agreement with various parameters including wave amplitude, wave speed, and wave number. Quantifying these characteristics are necessary towards understanding the mechanics of undulation and will aid in the design and control of underwater undulating robotics.
Effects of Tail Geometries on the Performance and Wake Pattern in Flapping Propulsion
Authors: Liu Geng , Dong Haibo
Published: December 2016

Swimming fishes exhibit remarkable diversities of the caudal fin geometries. In this work, a computational study is conducted to investigate the effects of the caudal fin shape on the hydrodynamic performance and wake patterns in flapping propulsion. We construct the propulsor models in different shapes by digitizing the real caudal fins of fish across a wide range of species spanning homocercal tails with low aspect ratio (square shape used by bluegill sunfish, rainbow trout, etc.) or high aspect ratio (lunate shape adopted by tuna, swordfish, etc.), and even heterocercal caudal fin adopted by sharks. Those fin models perform the same flapping motion in a uniform flow to mimic fish’s forward swimming. We then simulate the flow around the flapping fins by an in-house immersed-boundary-method based flow solver. According to the analysis of the hydrodynamic performance, we have found that the lunate shape model (high aspect-ratio) always generates a larger thrust compared to other models. The comparison of the propulsive efficiency shows that the large aspect ratio fins (tuna and shark) have a higher efficiency when the Strouhal number (St) is in the range of steady swimming (0.2<St<0.4), while the lower aspect ratio caudal fins (catfish, trout, etc.) are more efficient when St>0.4, in which the fish is accelerating or maneuvering. Finally, the 3D wake patterns of those propulsors are analyzed in detail.
Computational Fluid Dynamics in Undergraduate Engineering Education: A Short Introductory Tutorial to OpenFOAM
Authors: Nedyalkov Ivaylo , Wosnik Martin
Published: December 2016

Computational Fluid Dynamics (CFD) has become a widely used tool in industry as the cost for simulations is usually lower than the cost for multiple experiments. CFD is an effective tool for comparing design alternatives, investigating specific flow features and in some cases it may be the only feasible option for studying engineering flows. As a result, the demand for mechanical engineers with CFD skills keeps increasing. Nevertheless CFD is still not adequately presented in undergraduate engineering curricula, which can lead to expensive mistakes, if for example it is relied on without understanding its limitations. One excellent platform for CFD, which can be introduced to fluid mechanics classes, is the open-source environment OpenFOAM, which is widely used in both academia and industry. In addition to being open-source, OpenFOAM code can be viewed and modified by the user, and a wide range of modules for OpenFOAM are available with new modules being developed constantly. One major disadvantage, however, is that OpenFOAM has a rather steep learning curve and although there are many resources available online, it is difficult to find short introductory courses. A tutorial was developed to provide a brief introduction to OpenFOAM and allow the students to perform simple simulations. Upon completing the tutorial, the students can build their own simulations. The tutorial covers geometry, mesh, boundary and initial conditions, solvers, schemes, post processing, and some additional features, such as shell scripts and parallel processing. A large portion of the tutorial is devoted to the geometry and mesh generation as this is one of the more challenging aspects of OpenFOAM compared to conventional graphical user interface CFD packages. Nevertheless, the students are exposed to the importance of properly setting the other simulation parameters through simple examples — e.g., comparing 2D channel flow simulations using potential flow and using turbulence modeling. One crucial aspect of the tutorial is that students are encouraged to experiment with deliberate modifications of the simulations to experience and understand how some of them do not provide reasonable results. Although the tutorial is rather brief and does not cover the topics in much detail, it aims to familiarize students with the basics of OpenFOAM, so that they can better understand other relevant resources. The OpenFOAM tutorial offers an alternative introduction to CFD compared to commercial CFD packages, which may not be readily available. The tutorial has already been utilized for three consecutive years at the University of New Hampshire, mostly by undergraduate students who worked/are working on senior projects involving CFD. The feedback has been generally positive.
A Study on Performance of New Tidal Energy Converter for Tidal Current Extraction Using Computational Fluid Dynamics
Authors: Nguyen Manh Hung , Jeong Haechang , Yang Changjo
Published: December 2016

Renewal energy technologies are increasingly popular to ensure future energy sustainability and to balance environmental issues. The growing interest in exploring tidal energy has compelling reasons such as security and diversity of supply, intermittent but predictable and limited social and environmental impacts. The energy available in tidal currents or other artificial water channels is being considered as viable source of renewable power. Hydrokinetic conversion systems, albeit mostly at its early stage of development, may appear suitable in harnessing energy from such renewable resources. A concept of tidal energy converter (TEC) which is based on shape of the conventional water wheels, is introduced in this study. Basically, this turbine has several special features that are potentially more advantageous than the conventional tidal turbines, such as propeller type tidal turbines. The research aims to study the possibility of twelve-blade turbine in extracting the hydrokinetic energy of tidal current and converting it into electricity, and evaluate the performance of the turbine at different given arrangements of blades (single and double rows) using Computational Fluid Dynamics (CFD). In all cases of tip-speed ratio (TSR), the twelve-blade double-row type obtains higher power efficiency, especially about 20% power coefficient at TSR = 0.75, in comparison with 13% power coefficient of the single-row one. Furthermore, by changing the arrangement of rotating blades, the torque’s absorption from the rotor shaft of twelve-blade double-row turbine is more uniform due to the less interrupted and fluctuated generation of force for a period of time (one revolution of the rotor).
Research on the Threshold of Flow State of Viscous Fluids Based on Chaotic Dynamics
Authors: Lan Chao-Feng , Su Wen-Tao , Zhang Meng , Cai Wei-Hua , Li Feng-Chen
Published: December 2016

In order to choose the threshold of different fluid state and reveal the physical mechanism of the flow, the thermal convection of channel flow of viscous fluid is investigated by the chaos dynamics in this paper, in which the temperature at lower plate is slightly higher than the upper plate. Based on the Navies-Stokes equations of viscous fluids, the heat conduction equations of the troposphere, the changes of temperature and velocity fields and a truncated Fourier representation, the low-dimensional nonlinear dynamic equations of viscous fluids can be obtained; Then, the low-dimensional nonlinear dynamic equations reduce to the Lorenz equations, the variations of bifurcation curve of the flow state with Prandtl and Rayleigh parameters were analyzed by the chaos dynamics. It can be seen that the Lyapunov exponent curve of the output characteristics of the system vary with Re parameters, and reveals the relationship between the threshold of Prandtl and Rayleigh parameters, as well as the flow state. The research of this article have important reference values on the physical mechanism and flow characteristics of viscous fluids.
CFD Analysis of Performance of Five-Stage High-Pressure Volute Pump
Authors: Suzuki Takayuki , Takemura Takashi
Published: December 2016

It is important in development of turbomachinery to predict their performance precisely. Especially the prediction of multistage pump performance is one of the challenging problems because internal phenomena which relate to the performance are complicated. Therefore, in this research, we verified accuracy of Computational Fluid Dynamics (CFD) in predicting performance of a five-stage high-pressure volute pump by comparing predicted values by CFD with measurement data. We tried two methods to predict the pump performance. One is a computation with a complete pump model which includes all five stages and leakage passages. This method can be expected to represent total internal flow phenomena. The other method is totaling up the performance data from separate computations of 1st–2nd stages and series stages. This method is simpler than the former and involves less computational cost. As a result, it was clarified that all the methods could predict pump head at the best efficiency point to some extent, even by steady computation. However, no prediction can predict positive gradient in Q-H curve which was observed in measurement at low flow rate. Except for the unsteady complete pump model computation, efficiency and shaft power could not be predicted precisely. In addition, at high flow rate, unsteady computation of the complete pump model shows the best agreement in head. In the complete pump model computation at high flow rate, the series stage next to the long crossover has larger head because of the influence of it. Therefore, the separated model has difficulty in representing series stages’ performance. In order to predict performance at high flow rate, unsteady computations also including properly the influence of the long crossover properly are necessary. In addition, to predict performance at low flow rate, unsteady computation is necessary.
Hydraulic Optimization and Loss Analyses of a Low Specific-Speed Centrifugal Pump With Variable-Thickness Blades
Authors: Li Shiyang , Wu Peng , Wu Dazhuan
Published: December 2016

This paper investigates the hydraulic and dynamic performance of a low specific-speed centrifugal pump with CFD simulation. Three different impellers are designed with different thickness distributions along the same mean line of the blades. The entropy production is introduced to study the energy losses in the three models and the energy loss distributions of the whole flow passages are fully revealed. The simplified energy loss equation is carefully validated by comparing the thermodynamic efficiency to the traditional hydraulic efficiency, and the errors between them can be considered acceptable. The circumferential Euler head distribution out of the impeller is used to predict the uniformity of the flow into the volute. To obtain the transient flow characteristics, the sliding mesh technique and the unsteady CFD simulation are applied and the pressure pulsations in the volute are well captured. The head fluctuation intensities of the three models are quantitatively compared under constant flow rate. The results show that the thickness distribution can affect the hydraulic performance to a large extent, and it can strongly affect the pressure pulsation in the volute.
A High-Fidelity Approach for the Simulation of Flow-Induced Vibration
Authors: Merzari Elia , Solberg Jerome , Fischer Paul , Ferencz Robert M.
Published: December 2016

Flow-induced vibration (FIV) is a widespread problem in energy systems because they rely on fluid movement for energy conversion. Vibrating structures may be damaged as fatigue or wear occur. Given the importance of reliable components in the nuclear industry, flow-induced vibrations have long been a major concern in the safety and operation of nuclear reactors. In particular, nuclear fuel and steam generators have been known to suffer from flow-induced vibrations and related failures. Over the past five years, the Nuclear Energy Advanced Modeling and Simulation program has developed the integrated multiphysics code suite SHARP. The goal of developing such a tool is to perform multiphysics modeling of the components inside a reactor core, the full reactor core or portions of it, and be able to achieve that with various levels of fidelity. This flexibility allows users to select the appropriate level of fidelity for their computational resources and design constraints. In particular SHARP contains high-fidelity single-physics codes for structural mechanics and fluid mechanics calculations: the structural mechanics implicit code Diablo and the computational fluid dynamics spectral element code Nek5000. Both codes are state-of-the-art. highly scalable (up to millions of processors in the case of Nek5000) tools that have been extensively validated. These tools form a strong basis on which to build an FIV modeling capability.

This work discusses in detail the implementation of a fluid-structure interaction methodology in SHARP for simulating flow-induced viration based on the coupling between Diablo and Nek5000. Initial verification and validation efforts are also discussed, with a focus on standard benchmark cases: the flow past a cylinder, the Turek benchmark, and the flow in a Coriolis flow meter.
Study of Fluid Structure Interaction Using Sharp Interface Immersed Boundary Method
Authors: He Long , Joshi Keyur , Tafti Danesh
Published: December 2016

In this work, we present an approach for solving fluid structure interaction problems by combining a non-linear structure solver with an incompressible fluid solver using immersed boundary method. The implementation of the sharp-interface immersed boundary method with the fluid solver is described. A structure solver with the ability to handle geometric nonlinearly is developed and tested with benchmark cases. The partitioned fluid-structure coupling algorithm with the strategy of enforcing boundary conditions at the fluid/structure interaction is given in detail. The fully coupled FSI approach is tested with the Turek and Hron fluid-structure interaction benchmark case. Both strong coupling and weak coupling algorithms are examined. Predictions from the current approach show good agreement with the results reported by other researchers.
Estimation of Uncertain Parameters for Thermal and Fluid Analysis in Engine Room of Construction Machinery Using Data Assimilation
Authors: Kusano Kazuya , Yamakawa Hironobu , Ikeda Kunihiko
Published: December 2016

Recently, the cooling system of hydraulic excavator is often designed using the thermal and fluid analysis to improve the cooling performance. The reliability of the analysis results is important, since it directly influences on the efficiency of development. In the present study, the uncertain parameters were estimated using the data assimilation method to increase the reliability of the thermal and fluid analysis in an engine room of a hydraulic excavator.

The ensemble Kalman filter (EnKF) was adapted as a data assimilation method, and the thermal and fluid analysis was conducted with the three-dimensional steady simulation based on the Reynolds-average Navier-Stokes equations. The estimated parameters were set to the total heat quantities released by heat exchangers and the flow rates of the coolants. The total heat quantity is a parameter used for the heat release calculation of a heat exchanger, and the flow rate of a coolant is specified at the inlet boundary. As measurement data, temperatures of coolants which were measured at the upstream and downstream of the heat exchangers were used. Initial parameters were generated by setting parameter values in a random manner.

The simulation using estimated parameters successfully predicted temperatures at the heat exchangers, where the maximum error was 3K. In addition, the reductions of the standard deviations of the uncertain parameters were confirmed. That means the reliability of the simulation was increased.
Experimental Study of the Operation Conditions of Stability on a Gamma Stirling Engine
Authors: Hachem Houda , Gheith Ramla , Aloui Fethi , Ben Nasrallah Sassi
Published: December 2016

Considering Stirling engines modern applications and cogeneration recovery energy from industrial process, the power of a Stirling prime mover is to be provided at a speed of rotation adapted to the operation of the receiver system (usually a generator) to exploit the performance of this machine under the conditions of its use (ie lowering of the rotational speed and torque transmitted rise or, more rarely, elevated speed and lowering the torque transmitted). Knowing that the hot air engine cannot change speed quickly and in order to have a well designed system, it is important to study the unsteady state conditions. In this work we present an experimental stability analysis of an irreversible heat engine working at different conditions. The experimental study aims at analyzing the effect of working parameters disruption on the stability of the Gamma Stirling engine. Parameters involved in this experimental study are the load pressure of the motor and the load applied to the Stirling engine. The influence of engine operating parameters on its torque and rotational speed is investigated. The time required by a gamma type Stirling engine to stabilize operation after disruption is estimated. Results show that after a small disruption, speed and temperature evolutions decays exponentially to the steady state determined by a relaxation time. It is assumed that the decrease of the applied power load to the engine or the increase of the load pressure leads to a speed up. And that the increase of the applied power load to the engine or the decrease of the load pressure leads to a speed down.
Molecular Dynamic Simulation of Couette Flow of Liquid Argon in Nanochannel
Authors: Esmaeilzadeh Hamed , Su Junwei , Su Chefu , Sun Hongwei
Published: December 2016

Fluid flow in nanochannels is attracting increasing attention for a wide range of potential applications such as drug delivery, desalination, and DNA analysis. As experimental study in nanoscales is still a challenging task facing scientific society, different numerical technologies such as Molecular Dynamics (MD) method are becoming powerful tools for understanding the fluid behaviors at molecular level in nanofluidics. In the present study, MD simulation method, which is based on Newton’s second law, is employed to study the liquid argon flows through smooth and rough nanochannels. The effects of various parameters including moving-wall speed, nanochannel height, pair coefficients of fluid/wall interaction, and surface roughness on velocity profiles and slip velocity were investigated. Preliminary results show that these parameters have a significant impact on the flows in nanoscales.
Comparison of antibody immobilization strategies in detection of Vibrio cholerae by surface plasmon resonance
Authors: Taheri Ramezan Ali , Rezayan Ali Hossein , Rahimi Fereshteh , Mohammadnejad Javad , Kamali Mehdi
Published: December 2016

Surface plasmon resonance immunosensor for the detection of bacterial cells was first reported in 1998 with high detection limit as much as 107 cfu/ml. Since then, many efforts have been made aiming to lower the detection limit and improve the sensitivity of detection. The aim of this study was to compare the effect of four most frequently used immobilization strategies, including direct physical adsorption (physisorption), covalent immobilization via self-assembled monolayer (SAM) formation, bioaffinity immobilization using protein G-mediated immobilization and using mixed SAM of alkane thiols on signal strength of detection of Vibrio cholerae using these modified surfaces. The most widely used strategy, covalent binding of antibodies to sensor chip via SAM formation, gave the highest immobilization density and mixed SAM of 20/80 (v/v) of 11-mercaptoundecanoic acid (11-MUA)/9-mercapto-1-nonanol resulted in the least surface coverage in antibody immobilization step. To optimize surface density in covalent immobilization, four different concentrations (12.5, 25, 50, and 100 μg/ml) of anti-OmpW were immobilized on 11-MUA modified gold chips and maximum interaction response was achieved at 25 μg/ml. The interaction response signals for detection of V. cholerae using immobilized anti-OmpW were in this order: Oriented immobilization using protein G/antibody complex > mixed SAM of 11-MUA and 9-mercapto-1-nonanol > homogenous 11-MUA SAM > direct physical adsorption. In order to evaluate interaction studies in real sample condition, waste water samples that were artificially spiked with V. cholerae were tested and the authors concluded that for real samples, it is better to setup experiment with low surface coverage such as mixed SAM to overcome nonspecific adsorption.
Atomic fluorine densities in electron beam generated plasmas: A high ion to radical ratio source for etching with atomic level precision
Authors: Boris David R. , Petrova Tzvetelina B. , Petrov George M. , Walton Scott G.
Published: December 2016

Electron beam generated plasmas are generally characterized by a high plasma density (>1010 cm−3), and very low electron temperatures (<1 eV), making them well-suited for next generation processing techniques where high fluxes of low energy ions are desirable. In addition, both modeling and optical emission spectroscopy indicate relatively low concentrations of atomic radicals compared to discharges. Due to their relevance to industrial etching applications, this work focuses on the characteristics of electron beam generated plasmas produced in fluorine-containing chemistries (SF6, CF4, F2), with particular attention paid to atomic fluorine densities. Atomic F* emission is measured in Ar/SF6, Ar/CF4, and Ar/F2 mixtures and the Ar 750 nm/F 704 nm line ratios are then used to calculate the F atom densities as a function of reactive gas concentration, the first radical density measurement in this type of plasma to date. These results are compared with F atom density calculations performed using a zero dimensional non-local thermodynamic equilibrium Boltzmann code for Ar/SF6 and Ar/F2 mixtures to understand and verify the line ratio analysis. Good agreement between modeling and measurements points to a uniquely high ion-to-atomic radical density in electron beam generated plasmas.
Fabrication and optical behavior of graded-index, moth-eye antireflective structures in CdTe
Authors: Chan Lesley , Ghoshal Amitabh , DeCuir Eric A. , Chen Yuan Ping , Morse Daniel E. , Gordon Michael J.
Published: December 2016

A simple and scalable method, based on dip-coat colloidal lithography, mask reduction, and plasma-based pattern transfer, is presented to create graded-index, moth eye-inspired antireflective features on II–VI semiconductors. Hexagonal arrays of isolated conical frusta with tunable geometry (top diameter = 200–1300 nm, pitch = 310–2530 nm, and height = 790–7100 nm) were realized by isotropic etching of various size silica colloid masks before pattern transfer into the underlying substrate. Substantial increases in single-side direct and total infrared (IR) transmission across the 4–20 μm range (9%–15% for CdTe thin films and 18% for bulk CdTe) were achieved, in excellent agreement with transfer matrix calculations and finite difference time domain optical simulations. The fabrication method presented can be used to enhance efficiency in multiple IR application areas including photovoltaics, optical system components, detectors, and focal plane array imagers.
Swim track kinematics and calling behavior attributed to Bryde's whales on the Navy's Pacific Missile Range Facility
Authors: Helble Tyler A. , Henderson E. Elizabeth , Ierley Glenn R. , Martin Stephen W.
Published: December 2016

Time difference of arrival methods for acoustically localizing multiple marine mammals have been applied to recorded data from the Navy's Pacific Missile Range Facility in order to localize and track calls attributed to Bryde's whales. Data were recorded during the months of August–October 2014, and 17 individual tracks were identified. Call characteristics were compared to other Bryde's whale vocalizations from the Pacific Ocean, and locations of the recorded signals were compared to published visual sightings of Bryde's whales in the Hawaiian archipelago. Track kinematic information, such as swim speeds, bearing information, track duration, and directivity, was recorded for the species. The intercall interval was also established for most of the tracks, providing cue rate information for this species that may be useful for future acoustic density estimate calculations.
Optoelectronically innervated soft prosthetic hand via stretchable optical waveguides
Authors: Zhao Huichan , O’Brien Kevin , Li Shuo , Shepherd Robert F.
Published: December 2016

Stretchable optical waveguides can sense curvature, elongation, and force in a prosthetic hand.
Structure-Activity Relationships of a Series of Echinocandins and the Discovery of CD101, a Highly Stable and Soluble Echinocandin with Distinctive Pharmacokinetic Properties
Authors: James Kenneth D. , Laudeman Christopher P. , Malkar Navdeep B. , Krishnan Radha , Polowy Karen
Published: December 2016

Echinocandins are a first-line therapy for candidemia and invasive candidiasis. They are generally safe with few drug interactions, but the stability and pharmacokinetic properties of currently approved echinocandins are such that each was developed for daily intravenous infusion. We sought to discover a novel echinocandin with properties that would enable more flexible dosing regimens, alternate routes of delivery, and expanded utility. Derivatives of known echinocandin scaffolds were generated, and an iterative process of design and screening led to the discovery of CD101, a novel echinocandin that has since demonstrated improved chemical stability and pharmacokinetics. Here, we report the structure-activity relationships (including preclinical efficacy and pharmacokinetic data) for the series of echinocandin analogs from which CD101 was selected. In a mouse model of disseminated candidiasis, the test compounds displayed clear dose responses and were generally associated with lower fungal burdens than that of anidulafungin. Single-dose pharmacokinetic studies in beagle dogs revealed a wide disparity in the half-lives and volumes of distribution, with one compound (now known as CD101) displaying a half-life that is nearly 5-fold longer than that of anidulafungin (53.1 h versus 11.6 h, respectively).
In vitro
activity data against panels of
Candida
spp. and
Aspergillus
spp. demonstrated that CD101 behaved similarly to approved echinocandins in terms of potency and spectrum of activity, suggesting that the improved efficacy observed
in vivo
for CD101 is a result of features beyond the antifungal potency inherent to the molecule. Factors that potentially contribute to the improved
in vivo
efficacy of CD101 are discussed.
Significant Divergence in Sensitivity to Antimalarial Drugs between Neighboring Plasmodium falciparum Populations along the Eastern Border of Myanmar
Authors: Zeng Weilin , Bai Yao , Wang Meilian , Wang Zenglei , Deng Shuang , Ruan Yonghua , Feng Shi , Yang Zhaoqing , Cui Liwang
Published: December 2016

Malaria parasites in different areas where malaria is endemic display different levels of resistance to antimalarial drugs as the result of varied drug use histories. To provide updated knowledge of drug sensitivities during the malaria elimination phase in Southeast Asia, an epicenter of multidrug resistance, we determined
in vitro
susceptibilities of culture-adapted
Plasmodium falciparum
isolates from two eastern border regions (Wa and Kachin) of Myanmar to 10 drugs. Despite their close proximity, the Kachin parasites displayed higher 50% inhibitory concentrations than the Wa parasites to chloroquine, piperaquine, naphthoquine, mefloquine, quinine, pyrimethamine, pyronaridine, lumefantrine, and dihydroartemisinin. Genotyping of genes associated with drug resistance also showed significant differences in the prevalence rates of mutant alleles between the two regions. Particularly, major
pfdhfr
mutations mediating pyrimethamine resistance and the
pfdhps
A437G mutation had significantly higher frequencies in the Kachin parasites (
P
< 0.005). Moreover, when
pfdhfr
and
pfdhps
were considered together, the wild-type allele was found only in the Wa samples (22.6%). In addition, the
pfmdr1
Y184F mutation reached 38.7% in the Kachin parasites, compared to 9.7% in the Wa parasites, whereas N86Y was only detected in the Wa parasites, at 22.6%. Furthermore, the F446I mutation and all mutations in the propeller domain of the
PfK13
gene were significantly more frequent in the Kachin parasites. Collectively, this work demonstrates that even in spatially closely separated regions, parasites can exhibit drastic differences in drug sensitivities and genetic makeups underlying drug resistance, which may reflect regionally different drug histories and genetic drift of these isolated parasite populations.
Prevalence of Extended-Spectrum-β-Lactamase- and/or Carbapenemase-Producing Escherichia coli Isolated from Yellow-Legged Gulls from Barcelona, Spain
Authors: Vergara Andrea , Pitart Cristina , Montalvo Tomás , Roca Ignasi , Sabaté Sara , Hurtado Juan Carlos , Planell Raquel , Marco Francesc , Ramírez Beatriz , Peracho Víctor , de Simón Mercé , Vila Jordi
Published: December 2016

Seventy-two (54.5%) out of 132 fecal samples from a group of yellow-legged gulls in Barcelona, Spain, were positive for
Escherichia coli
producing either extended-spectrum β-lactamases (ESBL) (51.5%), carbapenemase (1.5%), or cephamycinase (1.5%). The isolation of two carbapenemase-producing
E. coli
strains is a matter of concern.
Carbapenemase-Producing Enterobacteriaceae in Swine Production in the United States: Impact and Opportunities
Authors: Johnson Timothy J.
Published: December 2016

The discovery of carbapenemase-producing
Enterobacteriaceae
in U.S. swine production is troubling and underscores a tumultuous period where the outlook on the battle against superbugs is bleak. However, all is not lost. This commentary highlights both the good and the bad that can come from such findings, including those of a recent study published by Mollenkopf et al. (Antimicrob Agents Chemother 61:e012198-16, 2017,
https://doi.org/doi:10.1128/AAC.01298-16
).
Outer Membrane Proteins BB0405 and BB0406 Are Immunogenic, but Only BB0405 Is Required for Borrelia burgdorferi Infection
Authors: Shrestha Binu , Kenedy Melisha R. , Akins Darrin R.
Published: December 2016

We recently identified the
Borrelia burgdorferi
outer membrane protein (OMP) BB0406 and found that the gene encoding this OMP was cotranscribed with the gene encoding the OMP BB0405. Interestingly, BB0405 and BB0406 share 59% similarity and are grouped into the same
B. burgdorferi
paralogous gene family. Given their overall similarity, it is plausible that both OMPs have similar or overlapping functions in this pathogenic spirochete. BB0405 was recently shown to be required for mammalian infection despite the observations that BB0405 is poorly immunogenic and not recognized during mouse or human infection. BB0405 orthologs have also been shown to bind the complement regulator protein factor H. Therefore, to better elucidate the role of BB0405 and its paralog BB0406 during infection and in serum resistance, we examined both proteins in animal infection, factor H binding, and serum sensitivity assays. Our combined results suggest that BB0405- and BB0406-specific antibodies are borreliacidal and that both OMPs are immunogenic during nonhuman primate infection. Additionally, while BB0405 was found to be required for establishing mouse infection, BB0406 was not found to be essential for infectivity. In contrast to data from previous reports, however, neither OMP was found to bind human factor H or to be required for enhancing serum resistance of
B. burgdorferi
in vitro
.
Nonequilibrium degassing, regassing, and vapor fluxing in magmatic feeder systems
Authors: Watkins J.M. , Gardner J.E. , Befus K.S.
Published: December 2016

Magma degassing models typically invoke volatile depletion of a single parental melt, with permeable loss of exsolved gas having served for many years as the paradigm for the transition from volatile-rich, explosive eruptions to volatile-depleted lava flows. These degassing models are guided by measurements of H2O, CO2, and hydrogen isotope variations retained in melt that quenched to glass, but the existing models are not uniquely constrained by the data. There also remains uncertainty surrounding the origin and significance of volcanic glass fragments. We show that individual obsidian pyroclasts from Mono Craters, California (USA), are heterogeneous in dissolved H2O and CO2, suggesting that clasts are assembled from juvenile melt and rewelded ash during magma ascent. This is in contrast to the conventional view that clasts are chemically homogeneous and sample the chilled, glassy margins of conduit walls. The new measurements of dissolved H2O and CO2 help reconcile existing open-system degassing models used to explain elevated CO2/H2O ratios, provide time scales based on diffusion modeling for pyroclast formation, and show that magma does not necessarily lose volatiles monotonically during ascent-driven decompression.
Subjective well-being and training load predict in-season injury and illness risk in female youth soccer players
Authors: Watson Andrew , Brickson Stacey , Brooks Alison , Dunn Warren
Published: December 2016

Background

The purpose of this study was to evaluate the effects of training load (TL) and well-being on injury and illness risk in youth soccer players.

Methods

Throughout a 20-week season, 75 female adolescent soccer players reported mood, fatigue, stress, soreness, sleep quality, sleep hours, TL, injuries and illnesses. Well-being measures were recorded from −3 (worst) to +3 (best). TL was expressed as daily, weekly and monthly, as well as an acute:chronic workload ratio (weekly divided by monthly). Variables were compared between days with and without an injury, and with or without an illness. Poisson regression models were developed to predict daily injuries and illnesses using well-being and TL (z-scores) as predictors.

Results

36 injuries and 52 illnesses were recorded. Days with an injury had lower (worse) daily mood (1.24±0.2 vs 1.16±0.1, p=0.012) and higher daily TL (517±138 vs 440±158, p=0.010). Average monthly TL was higher preceding days with an illness (12 442 ±409 vs 12 627 ±403, p=0.043), while no differences were found with respect to other measures of TL or well-being. Worse daily mood (p=0.011, OR=0.012), higher daily TL (p<0.001, OR=1.98), and higher prior day TL (p=0.040, OR=1.34) were independent predictors of injury, while weekly (p=0.005, OR=1.50) and monthly TL (p=0.007, OR=1.54) were predictors of illness.

Conclusions

Lower mood and higher acute TL are associated with increased injury risk, while higher chronic TL increases the risk of illness. Monitoring well-being and TL may facilitate intervention to reduce in-season injury and illness.
Neurosarcoidosis: unusual presentations and considerations for diagnosis and management
Authors: Radwan Walid , Lucke-Wold Brandon , Robadi Ibrahim Ahmed , Gyure Kymberly , Roberts Thomas , Bhatia Sanjay
Published: December 2016

Background

Sarcoidosis is a chronic, multisystem disease characterised by non-necrotising granulomatous inflammation of unknown aetiology. Most commonly, the lungs, lymph nodes, skin and eyes are affected in sarcoidosis; however, nervous system involvement occurs in approximately 5%–15% of cases. Any part of the nervous system can be affected by sarcoidosis.

Cases

Herein we describe three unusual patient presentations of neurosarcoidosis, one with optic neuritis, a second with hydrocephalus and a third with cervical myelopathy.

Conclusions

We include pertinent details about their presentations, imaging findings, pathology, management and clinical course.
Quantum cosmology on (k = −1)-Friedmann–Robertson–Walker Universe evolving from stiff matter era to the dust dominated one
Authors: Dariescu Marina-Aura , Dariescu Ciprian
Published: December 2016

This work is devoted to the spatially open Friedmann–Robertson–Walker (FRW) Universe evolving from the stiff matter era to the dust dominated one. Within the quantum analysis based on the Wheeler–DeWitt equation, we derive the wave function of the [Formula: see text]-FRW Universe with combined matter sources. On the classical level, one has to deal with the Friedmann equation which leads on a dependence of the scale function on time generally expressed from functional relations involving elliptic integrals.
Parity-dependent non-commutative quantum mechanics
Authors: Chung Won Sang
Published: December 2016

In this paper, we consider the non-commutative quantum mechanics (NCQM) with parity (or space reflection) in two dimensions. Using the parity operators Ri, we construct the deformed Heisenberg algebra with parity in the non-commutative plane. We use this algebra to discuss the isotropic harmonic Hamiltonian with parity.
Achieving Dynamic Data Guarantee and Data Confidentiality of Public Auditing in Cloud Storage Service
Authors: Hwang Min-Shiang , Sun Tsuei-Hung , Lee Cheng-Chi
Published: December 2016

Recently, storage as a service of cloud computing becomes a new trend to access or share files. Once files are stored in cloud, owner can access files seamlessly by personal computer or mobile device. However, owner may worry about confidentiality and integrity of owner's files stored in cloud because cloud service providers are not always trustworthy. Therefore, there are many kinds of data correctness verification methods proposed to prevent cloud service providers from cheating data owners. Among these models for auditing, bilinear pairing can achieve the most efficient way to verify data correctness and batch auditing. Although auditing methods can ensure whether data is stored properly, it is not considered that the data may be a secret data or a data owner does not want to be known by both auditors and cloud service providers. Another important issue is providing dynamic data of auditing in cloud. Wang et al.13proposed a scheme that can provide public auditing and dynamic data, but it still cannot guarantee whether cloud has updated data honestly. For this reason, we propose a dynamic data guarantee and data confidentiality scheme for public auditing in cloud storage service.
A Survey of Authentication and Communications Security in Online Banking
Authors: Kiljan Sven , Simoens Koen , Cock Danny De , Eekelen Marko Van , Vranken Harald
Published: December 2016

A survey was conducted to provide a state of the art of online banking authentication and communications security implementations. Between global regions the applied (single or multifactor) authentication schemes differ greatly, as well as the security of SSL/TLS implementations. Three phases for online banking development are identified. It is predicted that mobile banking will enter a third phase, characterized by the use of standard web technologies to develop mobile banking applications for different platforms. This has the potential to make mobile banking a target for attacks in a similar manner that home banking currently is.
Automated Planning for Ubiquitous Computing
Authors: Georgievski Ilche , Aiello Marco
Published: December 2016

The goal of ubiquitous computing is to create ambience in which one’s experiences and quality of life are improved by monitoring and assisting people using ubiquitous technologies and computation in coherence. The continuous advancements of involved technologies, such as wireless communications, mobile devices, and sensors, imply fast evolution of ubiquitous computing environments too. The complexity of these environments is reaching a point where traditional solutions simply no longer work. The environments are in need of computational techniques that can deal with the evolution and uncertainty of ubiquitous computing environments dynamically and automatically. Artificial Intelligence (AI) can contribute towards satisfying this future scenario in many ways, while numerous approaches inspired by work in the AI planning community have already been designed for ubiquitous computing. We devote this study to investigate the current progress of AI planning for ubiquitous computing by analysing those approaches. We rigorously search for and select relevant literature out of which we extract qualitative information. Using the extracted qualities, we derive a generic framework that consists of aspects important to planning for ubiquitous computing. The framework’s main purpose is to facilitate the understanding of those aspects, and classify the literature according to them. We then analyse the literature in a consolidated way, and identify future challenges of planning for ubiquitous computing.
Affinity-Based Thread and Data Mapping in Shared Memory Systems
Authors: Diener Matthias , Cruz Eduardo H. M. , Alves Marco A. Z. , Navaux Philippe O. A. , Koren Israel
Published: December 2016

Shared memory architectures have recently experienced a large increase in thread-level parallelism, leading to complex memory hierarchies with multiple cache memory levels and memory controllers. These new designs created a Non-Uniform Memory Access (NUMA) behavior, where the performance and energy consumption of memory accesses depend on the place where the data is located in the memory hierarchy. Accesses to local caches or memory controllers are generally more efficient than accesses to remote ones. A common way to improve the locality and balance of memory accesses is to determine the mapping of threads to cores and data to memory controllers based on the affinity between threads and data. Such mapping techniques can operate at different hardware and software levels, which impacts their complexity, applicability, and the resulting performance and energy consumption gains. In this article, we introduce a taxonomy to classify different mapping mechanisms and provide a comprehensive overview of existing solutions.
Dynamic witnesses for static type errors (or, ill-typed programs usually go wrong)
Authors: Seidel Eric L. , Jhala Ranjit , Weimer Westley
Published: December 2016

Static type errors are a common stumbling block for newcomers to typed functional languages. We present a dynamic approach to explaining type errors by generating counterexample witness inputs that illustrate how an ill-typed program goes wrong. First, given an ill-typed function, we symbolically execute the body to synthesize witness values that make the program go wrong. We prove that our procedure synthesizes general witnesses in that if a witness is found, then for all inhabited input types, there exist values that can make the function go wrong. Second, we show how to extend the above procedure to produce a reduction graph that can be used to interactively visualize and debug witness executions. Third, we evaluate the coverage of our approach on two data sets comprising over 4,500 ill-typed student programs. Our technique is able to generate witnesses for 88% of the programs, and our reduction graph yields small counterexamples for 81% of the witnesses. Finally, we evaluate whether our witnesses help students understand and fix type errors, and find that students presented with our witnesses show a greater understanding of type errors than those presented with a standard error message.
A glimpse of Hopjs
Authors: Serrano Manuel , Prunet Vincent
Published: December 2016

Hop.js is a multitier programming environment for JavaScript. It allows a single JavaScript program to describe the client-side and the server-side components of a web application. Its runtime environment ensures consistent executions of the application on the server and on the client.

This paper overviews the Hop.js design. It shows the JavaScript extensions that makes it possible to conceive web applications globally. It presents how Hop.js interacts with the outside world. It also briefly presents the Hop.js implementation. It presents the Hop.js web server implementation, the handling of server-side parallelism, and the JavaScript and HTML compilers.
Elaborator reflection: extending Idris in Idris
Authors: Christiansen David , Brady Edwin
Published: December 2016

Many programming languages and proof assistants are defined by elaboration from a high-level language with a great deal of implicit information to a highly explicit core language. In many advanced languages, these elaboration facilities contain powerful tools for program construction, but these tools are rarely designed to be repurposed by users. We describe
elaborator reflection
, a paradigm for metaprogramming in which the elaboration machinery is made directly available to metaprograms, as well as a concrete realization of elaborator reflection in Idris, a functional language with full dependent types. We demonstrate the applicability of Idris’s reflected elaboration framework to a number of realistic problems, we discuss the motivation for the specific features of its design, and we explore the broader meaning of elaborator reflection as it can relate to other languages.