bluuebunny/crossref_metadata_2025 huggingface dataset:
Power Transformer Fault Diagnosis Based on Vibration Correlation Analysis
Authors: Hong Kaixing , Huang Hai
Published: April 2016

In this paper, a condition assessment model using vibration method is presented to diagnose winding structure conditions. The principle of the model is based on the vibration correlation. In the model, the fundamental frequency vibration analysis is used to separate the winding vibration from the tank vibration. Then, a health parameter is proposed through the vibration correlation analysis. During the laboratory tests, the model is validated on a test transformer, and manmade deformations are provoked in a special winding to compare the vibrations under different conditions. The results show that the proposed model has the ability to assess winding conditions.
Design Specifications for Biaxial Navigation-Grade MEMS Accelerometers
Authors: Shan Xiaowei , Zou Ting , Forbes James Richard , Angeles Jorge
Published: April 2016

The focus of this paper is the design of a biaxial MEMS accelerometer for navigation applications. First, a survey is conducted to outline the commercial landscape of navigation-grade and MEMS accelerometers. The survey shows a potential market for navigation-grade accelerometers at the MEMS scale. Based on the specifications for navigation applications, the design targets are derived for the proposed biaxial MEMS accelerometers, including the common concerns of natural frequency ratios and bandwidth, as well as the important parameters for MEMS devices, such as hinge width, proof-mass size and mobility range. In light of the design targets, the ideal frequency matrix of the biaxial accelerometer system is derived based on the concept of generalized spring, in connection with the design targets. The stiffness values required are estimated herein. For further structural optimization, the parametric entries of the frequency-ratio matrix act as the objectives to be maximized for the lowest off-axis sensitivity of the proposed accelerometer. A suitable architecture for MEMS biaxial accelerometers is proposed thereafter. This architecture not only provides high compliance and structural isotropy for the in-plane translation, but also allows for direct measurement of the proof-mass motion. The proposed architecture is then optimized for the highest frequency ratio between the non-sensitive and sensitive axes, with regard to the design parameters and constraints. The optimization results of the proposed accelerometer demonstrate navigation-grade mechanical performance.
Tooth Contact Analysis of Planetary Gear Trains and its Transmission Error Experiments and Frequency Spectrum Analysis
Authors: Xu Kai , Xu Aijun , Yang Jianjun , Qiu Ming , Su Jianxin
Published: April 2016

Based on Tooth Contact Analysis (TCA), a feasible approach for Transmission Error (TE) of planetary gear train is proposed in this paper as follows: the first step is to proceed a specific analysis of the TE from the planetary gear train with only one planet, the second step is to calculate each phase difference of planets in the gear train. Then the total TE of a planetary gear train can be calculated simply by the two steps. The paper points out 3 kinds of positional difference of planets: coincidence, equalization, imparity and their respective effect on the total TE of the gear train, then draws a conclusion that the equalization is the optimized one among the above three. Eventually, the TE experiment of the planetary gear train is performed, and spectrum analysis is adopted in the paper.
Dirac-Like Cones at Low-Symmetry Points in Phononic Crystals
Authors: Cao Huixian , Mei Jun
Published: April 2016

Many of graphene’s interesting properties originate from its unique dispersion relations around the K point, a high symmetry point in the Brillouin zone (BZ), where two bands cross over each other linearly. In this paper, we study the Dirac-cone-like dispersion relations around the low symmetry points in the BZ of a classical system, i.e., a2D phononic crystal consisting of a triangular array of square-shaped cylinders embedded in water host. We find that the linear dispersions around the degenerate point form a tilted and anisotropic cone, which means not only that the band slopes can be quite different along different k directions, but also that even for the same k direction, the band slopes above and below the degenerate frequency can be very different. The anisotropic behavior in the reciprocal space can be understood in terms of the effective Hamiltonian, which is constructed from the eigenstates at that degenerate point. In addition, the linear slopes of the Dirac-cone-like dispersions along any direction can be accurately predicted by the k.p method and the results of which agree very well with the rigorous band structure calculations. Based on the peculiar anisotropic band structures, some interesting acoustic wave transmission phenomena are investigated.
Continuous Separation of Cancer Cells From Blood in a Microfluidic Channel Using Dielectrophoresis
Authors: Alazzam Anas , Stiharu Ion , Khashan Saud
Published: April 2016

Currently, there is enormous interest in developing microfluidic lab-on-a chip devices for biological and clinical purposes. In this work, a method for continuous separation of cancer cells from diluted blood in a microfluidic device using dielectrophoresis is described. MDA-MB-231 breast cancer cells have been separated from normal blood cells with high level of accuracy that could enabled precise counting of the cancer cells in samples. The cancer cells were separated from the mixture of cells to a different daughter channel using two pairs of interdigitated comb-like electrode deposited in the microchannel. All experiments were performed with sucrose/dextrose conductivity adjusted medium. The AC signals used in the separation of cancer cells from the mixture are 20 V peak-to-peak with frequencies in range of 10–60 kHz. The separation is a result of balancing of magnitude of the dielectrophoretic force and hydrodynamic force on cells. The difference in response in response between cancer malignant cells and normal cells at a certain band of alternating current frequencies was used for rapid separation of cancer cells from blood. The significance of these experimental results are discussed, with detailed reporting on the preparation of cells and medium, flow condition and the fabrication process of the microfluidic separation microdevice. The present technique could potentially be applied to identify incident cancer at a stage and size that is not yet detectable by standard diagnostic techniques for detecting of cancer recurrences.
Finite Element Analysis of Polyurethane Based Composite Shafts Under Different Boundary Conditions
Authors: Rahman Mosfequr , Aktaruzzaman F. N. U. , Absar Saheem , Mitra Aniruddha , Hossain Awlad
Published: April 2016

Depending on the type of matrix materials, composites can be broadly divided into three different major classifications: Organic-matrix composites (OMC), metal-matrix composites (MMC), and ceramic-matrix composites (CMC). OMC can be further sub-classified into polymer-matrix composites (PMC) and carbon-matrix composites or carbon-carbon composites. In this paper the main objective is to focus on polyurethane based PMC composites. Polyurethane is one of the widely used polymer matrix materials. It has diversified applications, easily available and cheap. In this computational study a composite shaft with a core made of matrix material completely wrapped around by a woven fiber cloth with a very strong bonding between core and fibers is considered. Three different types of woven fibers: fiber glass, Kevlar 49, and carbon fibers, are considered. A woven fabric is the interlocking or weaving of two unidirectional fibers. This configuration is often used to produce curve surfaces because of the ease with which it could be placed on and conform to curved surfaces. Authors had fabricated these three composites in their in-house laboratory. They had also experimentally measured the mechanical properties of these composites using 3-point bending test which already been published.

In this current study finite element analyses has been performed for the modeling of the static response of these three different polyurethane based composite shafts as fiber glass reinforced polyurethane epoxy, carbon fiber reinforced polyurethane epoxy, and Kevlar fibers reinforced polyurethane epoxy for three different boundary conditions. These three boundary conditions are simply supported, cantilever, both end fixed types with bending loads applied at the middle for simply supported case and distributed load along the length of the shaft for the last two types of boundary conditions. A three dimensional model of the composite beam has been implemented in this study using SolidWorks. A finite element commercial software ANSYS is used to investigate the stress response and deformation behavior of the model geometry for these three polyurethane based composite shafts for these three boundary conditions. A twenty node three dimensional element has been implemented for the finite element formulation of the modeled geometry such that it is applicable for the analysis of a layered composite structure, while providing support for linear, large rotation, and large strain nonlinear loading conditions. Convergence has also been ensured for various mash configurations in this work.
Development of All-Plastic Microvalve Array for Multiplexed Immunoassay
Authors: Augustine Shancy , Gu Pan , Zheng Xiangjun , Nishida Toshikazu , Fan Z. Hugh
Published: April 2016

There is a need for low-cost immunoassays that measure the presence and concentration of multiple harmful agents in one device. Currently, comparable immunoassays employ a one-analyte-per-test format that is time consuming and not cost effective for the requirement of detecting multiple analytes in a single sample. For instance, if a spectrum of harmful agents, including E. coli O157, cholera toxin, and Salmonella typhimurium, should be simultaneously monitored in foods and drinking water, then a one-analyte-per-test would be inefficient. This work demonstrates a platform capable of simultaneous detection of multiple analytes in a single, low-cost, microvalve array-enabled multiplexed immunoassay. This multiplexed immunoassay platform is demonstrated in a prototype COC (cyclic olefin copolymer) device with a 2×3 array in which 6 analytes can be detected simultaneously. In order to contain and regulate the flow of reagents in the multichannel device, an array of microfluidic valves actuated by a thermally expandable material and microfabricated resistors have been developed to direct the flow to the necessary assay sites. The microvalve-based immunoassay is shown to be reliable, easy to operate, and compatible with large-scale integration. The all-plastic microvalves use paraffin wax as the thermally sensitive material which drastically reduces power consumption by latching upon closing so that pulsed power is required only to close and latch the microvalve until it is necessary to re-open the valve. The multiplexed detection scheme has been demonstrated by using three proteins, C reactive protein (CRP) and transferrin, both of which are biomarkers associated with traumatic brain injury (TBI) as well as bovine serum albumin (BSA) as the negative control. Since there are no external bulky pneumatic accessories required to operate/latch the microvalves in the device, this compact, thermally actuated and latching microvalve-enabled multiplexed immunoassay has the potential to realize a portable, low power, battery operated microfluidic device for biological assays.
A Microboiler: Waste Heat to Power Scavenging System
Authors: Thapa S. , Borquist E. , Baniya A. , Fang J. , Wood D. , Weiss L.
Published: April 2016

This paper presents the detailed fabrication and baseline operational characterization of a miniature device capable of recovering waste heat for power. Waste heat to power is the process of scavenging heat from a large process as a result of mechanical inefficiencies and using that heat to generate useful power. To address this waste heat to power recovery approach, a MEMS based microboiler has been investigated in this work which is capable of capturing waste heat. The microboiler consists of a micro fabricated boilerplate and a steamdome. The boilerplate has been designed with capillary channels capable of driving fluid flow from the surrounding reservoirs to the heated surface, thus eliminating the need of an electrically powered flow pump. The working fluid undergoes phase change inside the enclosed central steamdome attached atop the boilerplate. This pressurized vapor can be made available to another MEMS device such as PZT membrane capable of generating mechanical or electrical power. In this way, the discarded heat from the larger process can be utilized to generate power output.

In contrast to the previous work, a thick acrylic steamdome has been replaced with a thin glass steamdome to minimize premature condensation of vapor due to heat loss via large mass. The tests were performed on the microboiler with the input powers of 1.8 W and 2.7 W and the comparisons of the results were carried out using a simulation model. The average temperatures at the top of the boilerplate were 106° C and 144° C for the power inputs of 1.8 W and 2.7 W, respectively. The available powers at the top of the boilerplate via heat conduction were 1.14 W and 1.72 W for the power inputs of 1.8 W and 2.7 W for the supplied powers of 1.8 W and 2.7 W, respectively. With these known available power throughputs and the heat of vaporization of the future working fluid, the calculated maximum mass flow rates were 13.6 mg/s and 9.12 mg/s, respectively.
Thermal Resistance and PIV Characterization of a Line-Replaceable Compact Liquid-Cooled Server Module for High Performance Computing Platforms
Authors: Gess Joshua , Bhavnani Sushil H. , Johnson R. Wayne
Published: April 2016

The meteoric growth of social networking involvement along with cost-effective cloud based computing business models are just two reasons why data center power consumption is growing at an alarming rate. Dwindling global energy resources mandate that these data centers be more efficient, especially as our dependence and demand upon them grow. As the data center demand grows, components will be designed with reductions in volume and increases in processor speeds, resulting in increases in heat fluxes which two-phase liquid immersion techniques offer the potential of dissipating. The proposed experimental facility seeks to illustrate how these demands can be met through the integration of a small form factor line replaceable cartridge which contains heated elements meant to simulate components within a high performance computing unit. The facility also consists of thermal support equipment used for heat extraction and rejection to ambient much like one would find in a liquid cooled data center, such as a chiller, fluid pumps, etc. One way to effectively characterize the efficiency of a thermal design technique is to quantify the thermal resistance, and subsequently minimize it as much as possible. Incredibly low module level thermal resistances have been achieved, on the order of 0.13 K/W under pool conditions and as little as 0.10 K/W when flow is introduced within the electronics housing. Trends of the cartridge’s thermal resistance have been explored as exterior chilled water temperatures are varied, over several surface enhancements along with the variation of external chilled water and internal dielectric fluid flow rates. As has been noted by several authors in their study of immersion cooled modules, a condensation limit has been found and trends upon it associated with varying the previously mentioned parameters have also been documented. The effect upon thermal performance of diverting the flow over the primary heating elements in various ways has been explored through the use of Particle Image Velocimetry (PIV). These techniques have been used to illustrate how a new dielectric fluid flow distribution design resulted in increased mass flow rate over critical components within the cartridge.
Applying Incompatible Meshes for Modeling Structural-Acoustic Domains in Energy Finite Element Analysis
Authors: Medyanik S. N. , Vlahopoulos N.
Published: April 2016

The Energy Finite Element Analysis (EFEA) has been developed for modeling coupled structural-acoustic systems at mid-to-high frequencies when conventional finite element methods are no longer computationally efficient because they require very fine meshes. In standard Finite Element Analysis (FEA) approach, governing differential equations are formulated in terms of displacements which vary harmonically with space. This requires larger numbers of elements at higher frequencies when wavelengths become smaller. In the EFEA, governing differential equations are formulated in terms of energy density that is spatially averaged over a wavelength and time averaged over a period. The resulting solutions vary exponentially with space which makes them smooth and allows for using much coarser meshes. However, current EFEA formulations require exact matching between the meshes at the boundaries between structural and acoustic domains. This creates practical inconveniences in applying the method as well as limits its use to only fully compatible meshes.

In this paper, a new formulation is presented that allows for using incompatible meshes in EFEA modeling, when shapes and/or sizes of elements at structural-acoustic interfaces do not match. In the main EFEA procedure, joints formulations between structural and acoustic domains have been changed in order to deal with non-matching elements. In addition, the new Pre-EFEA procedure which allows for automatic searching and formation of the new types of joints is developed for models with incompatible meshes. The new method is tested using a spherical shaped structural-acoustic interface. Results for incompatible meshes are validated by comparing to solutions obtained using regular compatible meshes. The effects of mesh incompatibility on the accuracy of results are discussed.
A Microfluidic Device for Caenorhabditis Elegans Based Chemical Testing
Authors: Song Pengfei , Zhang Weize , Sobolevski Alexandre , Bernard Kristine , Hekimi Siegfried , Liu Xinyu
Published: April 2016

The nematode worm Caenorhabditis elegans has been employed as a popular model organism in many fields of biological research. In this paper, we present an easy-to-use microfluidic device for facilitating C. elegans based chemical testing. The device is capable of housing single worms in microfluidic chambers and precisely adjusting the chamber’s chemical environment during experiments. Eight worms can be readily loaded into the chambers through separate loading channels in a quick and gentle manner. In addition, a custom-made software with a graphic user interface is also created for quantitative analysis of locomotion parameters (swimming frequency and bend amplitude) of the worms in response to chemical stimuli, thus greatly enhancing the efficiency of data collection. We perform proof-of-concept experiments using two chemicals, zinc ion (Zn2+) and glucose, which demonstrate the capability and effectiveness of the microfluidic device.
Aeroacoustics of a Low-Speed Free Tip Fan With a Complex Clearance Geometry
Authors: Lallier-Daniels Dominic , Moreau Stephane , Sanjose Marlene
Published: April 2016

The influence of tip leakage flow on the performance of turbomachinery, both from an aerodynamic and acoustic point of view, has been demonstrated by several authors. However, most studies present in the literature are focused on the effects of tip leakage from an aerodynamic point of view and often forgo the mechanisms associated with the acoustics effect. The effect of different tip geometries is also still ill understood.

The current advancement of a numerical study delving into tip leakage flow noise in low-speed turbomachinery applications is presented in this paper. The study as a whole aims to investigate the mechanisms associated with tip leakage flow noise on different axial fans with varying tip configurations. The study is carried out using lattice-Boltzmann simulations that allow to obtain the aerodynamic and aeroacoustic field simultaneously.

As a first step in this investigation of tip flow noise, this paper focuses on a free-tip axial flow fan with a complex tip geometry. The global aerodynamic and acoustic performance of the fan is evaluated numerically and compared to available experimental results. An investigation of the simulated flowfield with regards to the observed acoustics is then carried out.
Study on Stress and Thermal Contraction During Cooling and Demolding in Hot Embossing
Authors: Gomez Juan A. , Lek Devanda , Song In-Hyouk , Chun Du-Hwan , You Byoung H.
Published: April 2016

Thermal stress and shrinkage were investigated to analyze pattern defects during the cooling and demolding steps in hot embossing. Hot embossing is one of the most popular fabrication methods that replicate polymer microdevices in fields such as micro-fluidics and micro-optics. Numerical models were developed to study the effect of thermal stress and adhesion force on a molded microstructure during the cooling and demolding steps of micro hot embossing. The alignment microstructure, a hemisphere-tipped post, was located at four radial locations of 5, 10, 15, and 20 mm from the center of the polymer substrate to determine the effect of thermal stress and adhesion forces, relative to pattern location, leading to pattern deformation. Results showed that thermal stress increased as the microstructure was moved further away from the center of the polymer substrate due to an increase in shrinkage velocity. Process parameters could be designed to improve replication fidelity by analyzing the stress distribution of a molded microstructure during cooling and demolding.
The Effect of Strain on the Electronic Properties of Graphene Nanoribbons
Authors: Yang Meng , Ohnishi Masato , Suzuki Ken , Miura Hideo
Published: April 2016

Graphene nano-ribbons (GNRs) have great potential for the application of field effect transistors (FET). However, in the graphene transfer and semiconductor device fabrication process, due to the thermal expansion and lattice mismatch between dissimilar materials, internal stress is easily formed in GNRs, leading to the undesirable deformation. Thus, the electronic states of GNRs are usually modified, which may degrade the reliability of GNRs-based nano-devices. We investigated the effect of tensile, bending and folding deformations on the electronic states of armchair GNRs (AGNRs) based on density functional theory (DFT) calculation and found that the electronic structure of AGNRs is very sensitive to the external deformation. When a uniaxial tensile stress is applied to AGNRs with width Na = 10, the band structure is modified, leading to the change in band gap approximately from 0 eV to 1.0 eV. Due to the orbital hybridization, the band gaps of bended and folded AGNRs decrease significantly when the maximum local dihedral angle exceeds a critical value. In order to clarify the effect of external stress on the electronic conductivity of GNRs, the current through AGNRs under uniaxial tension is analyzed using a non-equilibrium Green’s function approach based on π-orbital tight-binding approximation. It is found that at a relative large ribbon length Ns = 20, the uniaxial tensile strain can modify the band gap of AGNRs, leading to the change in the electronic conductivity. Moreover, the current-strain (I-ε) relationship of AGNRs changes significantly as the change in the length of strained area.
Nonlinear Guided Waves for Continuous Material Microstructure State Awareness
Authors: Lissenden Cliff J. , Liu Yang , Chillara Vamshi K. , Choi Gloria , Yao Xiaochu
Published: April 2016

This paper summarizes the characteristics of nonlinear ultrasonic guided waves and demonstrates the use of the nondispersive fundamental shear horizontal wave mode to generate a third harmonic that is sensitive to plastic strain and fatigue. Experimental results for an aluminum alloy plate are presented within the context of the current understanding of nonlinear guided waves. Due to the sensitive nature of higher harmonic measurements, instrumentation nonlinearities are discussed. In two different sets of experiments, the third harmonic generation is shown to be dependent upon (i) the plastic strain and (ii) the number of fatigue cycles. Thus, higher harmonic generation can provide material state awareness throughout the service life, especially before a macroscale crack initiates.
A Parametric Study of the Response of a Beam-Rigid-Body Microgyroscope
Authors: Lajimi S. A. M. , Heppler G. R. , Abdel-Rahman E.
Published: April 2016

A parametric study of a cantilever beam-based microgyroscope is presented. The microgyroscope is comprised of a cantilever beam with a rigid-body attached to its free end. The system is electrostatically forced in one direction and sensed in an orthogonal direction. This model of a beam-rigid-body MEMS gyroscope includes the effects of mass eccentricity and width-ratio. The effects of the large end mass (rigid-body) are presented via results for its static response and its linear dynamic response as characterized by its eigenfrequencies.
Antimicrobial activity of tantalum oxide coatings decorated with Ag nanoparticles
Authors: Cao Huiliang , Meng Fanhao , Liu Xuanyong
Published: April 2016

Silver plasma immersion ion implantation was used to decorate silver nanoparticles (Ag NPs) on tantalum oxide (TO) coatings. The coatings acted against bacterial cells (Staphylococcus epidermidis) in the dark by disrupting their integrity. The action was independent of silver release and likely driven by the electron storage capability of the Schottky barriers established at the interfaces between Ag NPs and the TO support. Moreover, no apparent side effect on the adhesion and differentiation of rat bone mesenchymal stem cells was detected when using Ag NPs-modified TO coatings. These results demonstrate that decoration of tantalum oxide using Ag NPs could be a promising procedure for improving the antibacterial properties for orthopedic and dental implants.
Zellweger syndrome with severe malnutrition, immunocompromised state and opportunistic infections
Authors: Cardoso Patrícia , Amaral Maria Emanuel , Lemos Sónia , Garcia Paula
Published: April 2016

Peroxisome biogenesis disorders are related to a spectrum of genetic diseases that range from severe Zellweger syndrome to milder infantile Refsum disease. Zellweger syndrome is characterised by dysmorphic features, severe hypotonia, seizures, failure to thrive, liver dysfunction and skeletal defects. Increased levels of very long chain fatty acids are the biochemical hallmark and the most common mutations found in the PEX1 gene. We report an unusual presentation of Zellweger syndrome in a 2-month-old female infant with severe malnutrition, opportunistic infections, lymphopaenia and a small thymic shadow on chest radiography. With this clinical picture, an initial hypothesis of primary immunodeficiency was considered. It was later confirmed to not be the case. On follow-up, global developmental delay, bilateral optic nerve atrophy and moderate bilateral sensorineural deafness grade II were documented. There were no further infectious complications and we concluded malnutrition was the cause of the infant's immunocompromised state.
Regional variation in otolith geochemistry of juvenile Atlantic cod (Gadus morhua) in coastal Newfoundland
Authors: Stanley Ryan R.E. , DiBacco Claudio , Thorrold Simon R. , Snelgrove Paul V.R. , Morris Corey J. , Gregory Robert S. , Campana Steven E. , Bradbury Ian R.
Published: April 2016

We examined spatial variation in otolith geochemistry as a natural tag in juvenile Atlantic cod (Gadus morhua) to resolve geographic patterns during early life history. Individuals from 54 inshore sites spanned five embayments in eastern Newfoundland. Otolith composition differed at all spatial scales and related inversely to spatial scale. Classification analysis revealed increasing discrimination at coarser spatial scales: site (26%–58%), bay (49%), and coast (76%). Assignment success declined by ∼10% per added site with increasing sampling sites per bay, demonstrating fine-scale (<100 km) variation. When we partitioned environmental variability from observed otolith chemistry using predictive models, assignment success improved by 56%, 14%, and 5% for site, bay, and coast, respectively. Our results demonstrate environmental influence on spatial structure of otolith chemistry and illustrate the importance of resolving baseline variability in otolith chemistry when conducting assignment tests. Collectively, our results describe the potential utility of juvenile otolith composition in evaluating contributions of subpopulations to the Northwest Atlantic cod stock and highlight important limitations imposed by environmental variation at scales less than 100 km.
Juvenile steelhead movements in relation to stream habitat, population density, and body size: consequences for individual growth rates
Authors: Myrvold Knut Marius , Kennedy Brian Patrick
Published: April 2016

Anadromous salmonids can display considerable movement within their natal streams prior to outmigration, reflecting behavioural responses to biotic and abiotic conditions. Here we quantify dispersal and site fidelity in juvenile steelhead (Oncorhynchus mykiss) over four weeks in the fall, their consequences for individual growth rates, and how habitat, density, and individual body size can explain individual movement decisions. Retention rates ranged from 29% to 66% and were greater among yearlings (61%) than subyearlings (31%). Site fidelity in yearlings was best predicted by individual body mass (negative relationship), and site fidelity in both age classes was positively related to pool habitat availability. An experimental increase in density caused depressed growth rates in both age classes, and site fidelity was lower among translocated fish than among individuals originally residing in the manipulated sites. Within control sites, there were no significant consequences of movement for growth rates in either age class. These results show that movement rates can vary in response to local conditions and that growth rates in movers can equal or exceed those of sedentary individuals.
pH affects bacterial community composition in soils across the Huashan Watershed, China
Authors: Huang Rui , Zhao Dayong , Zeng Jin , Shen Feng , Cao Xinyi , Jiang Cuiling , Huang Feng , Feng Jingwei , Yu Zhongbo , Wu Qinglong L.
Published: April 2016

To investigate soil bacterial richness and diversity and to determine the correlations between bacterial communities and soil properties, 8 soil samples were collected from the Huashan watershed in Anhui, China. Subsequently, 454 high-throughput pyrosequencing and bioinformatics analyses were performed to examine the soil bacterial community compositions. The operational taxonomic unit richness of the bacterial community ranged from 3664 to 5899, and the diversity indices, including Chao1, Shannon–Wiener, and Faith’s phylogenetic diversity ranged from 7751 to 15 204, 7.386 to 8.327, and 415.77 to 679.11, respectively. The 2 most dominant phyla in the soil samples were Actinobacteria and Proteobacteria. The richness and diversity of the bacterial community were positively correlated with soil pH. The Mantel test revealed that the soil pH was the dominant factor influencing the bacterial community. The positive modular structure of co-occurrence patterns at the genus level was discovered by network analysis. The results obtained in this study provide useful information that enhances our understanding of the effects of soil properties on the bacterial communities.
Investigation of 1377C/T polymorphism of the Toll-like receptor 3 among patients with chronic hepatitis B
Authors: Goktas Emine Firat , Bulut Cemal , Goktas Mustafa Tugrul , Ozer Erdem Kamil , Karaca Ragip Ozgur , Kinikli Sami , Demiroz Ali Pekcan , Bozkurt Atilla
Published: April 2016

The immunopathogenesis of chronic hepatitis B (CHB) has not been clarified yet. Toll-like receptors (TLR) are a receptor family that initiates immunity with exogenous–endogenous ligands and plays a role in the pathogenesis of infections. In this study, we aimed to investigate the frequency of TLR 3 1377C/T (rs3775290) polymorphism and its role in patients with CHB. We included 50 healthy individuals as control group and 73 active and 43 inactive hepatitis B patients. All DNA samples were isolated from blood samples. For the detection of TLR 3 1377C/T single-nucleotide polymorphism, restriction fragment length polymorphism was used. A statistically significant difference was determined in Hepatitis B virus (HBV) DNA levels of CHB patients with the CC, CT, and TT genotypes (p = 0.013). The highest levels of HBV DNA were detected in individuals with TT genotypes. Additionally, the frequency of CC genotype was higher in the active CHB patients compared with that of the inactive CHB patients (p = 0.044). No statistically significant difference in TLR 3 1377C/T polymorphism was detected between healthy controls and the hepatitis B patients (p = 0.342). In conclusion, HBV DNA level was higher in the individuals with TT genotype, and CC genotype was more frequent in the active CHB patients. These results suggest a possible association between CHB and TLR 3 gene (1377C/T) polymorphism.
Rapid determination of n-6 and n-3 fatty acid ratios in cereal grains and forages by 1H NMR spectroscopy
Authors: Prema D. , Jensen J. , Pilfold J.L. , Turner T.D. , Donkor K.K. , Cinel B. , Church J.S.
Published: April 2016

Herein we describe a new method to rapidly determine the n-6/n-3 fatty acid ratios in cereal grains and forages (hydroponically-grown cereal sprouts and haylage) using 1H nuclear magnetic resonance (NMR) spectroscopy. This NMR method was found to be consistent with more established but time-consuming gas chromatographic methods (R = 0.994).
Extended negativity measure for multipartitek-nonseparable states
Authors: Wang Yinzhu , Wang Danxia , Huang Li
Published: April 2016

In this paper, an extended negativity entanglement measure for multipartite k-nonseparable states with respect to k-partition was proposed. We show that this measure is well-defined, i.e. it satisfies some basic properties as an entanglement measure. In addition, we give a relation between this measure and k-ME concurrence, and obtain a lower bound of this measure.
LED Curing Lights and Temperature Changes in Different Tooth Sites
Authors: Armellin E. , Bovesecchi G. , Coppa P. , Pasquantonio G. , Cerroni L.
Published: April 2016

Objectives.The aim of thisin vitrostudy was to assess thermal changes on tooth tissues during light exposure using two different LED curing units. The hypothesis was that no temperature increase could be detected within the dental pulp during polymerization irrespective of the use of a composite resin or a light-curing unit.Methods.Caries-free human first molars were selected, pulp residues were removed after root resection, and four calibrated type-J thermocouples were positioned. Two LED lamps were tested; temperature measurements were made on intact teeth and on the same tooth during curing of composite restorations. The data was analyzed by one-way analysis of variance (ANOVA), Wilcoxon test, Kruskal-Wallis test, and Pearson’sχ2. After ANOVA, the Bonferroni multiple comparison test was performed.Results.Polymerization data analysis showed that in the pulp chamber temperature increase was higher than that without resin. Starlight PRO, in the same condition of Valo lamp, showed a lower temperature increase in pre- and intrapolymerization. A control group (without composite resin) was evaluated.Significance.Temperature increase during resin curing is a function of the rate of polymerization, due to the exothermic polymerization reaction, the energy from the light unit, and time of exposure.
Stall Margin Improvement in a Centrifugal Compressor through Inducer Casing Treatment
Authors: Koyyalamudi V. V. N. K. Satish , Nagpurwala Quamber H.
Published: April 2016

The increasing trend of high stage pressure ratio with increased aerodynamic loading has led to reduction in stable operating range of centrifugal compressors with stall and surge initiating at relatively higher mass flow rates. The casing treatment technique of stall control is found to be effective in axial compressors, but very limited research work is published on the application of this technique in centrifugal compressors. Present research was aimed to investigate the effect of casing treatment on the performance and stall margin of a high speed, 4 : 1 pressure ratio centrifugal compressor through numerical simulations using ANSYS CFX software. Three casing treatment configurations were developed and incorporated in the shroud over the inducer of the impeller. The predicted performance of baseline compressor (without casing treatment) was in good agreement with published experimental data. The compressor with different inducer casing treatment geometries showed varying levels of stall margin improvement, up to a maximum of 18%. While the peak efficiency of the compressor with casing treatment dropped by 0.8%–1% compared to the baseline compressor, the choke mass flow rate was improved by 9.5%, thus enhancing the total stable operating range. The inlet configuration of the casing treatment was found to play an important role in stall margin improvement.
Investigation on the Inversion of the Atmospheric Duct Using the Artificial Bee Colony Algorithm Based on Opposition-Based Learning
Authors: Yang Chao , Zhang Jian-Ke , Guo Li-Xin
Published: April 2016

The artificial bee colony (ABC) algorithm is a recently introduced optimization method in the research field of swarm intelligence. This paper presents an improved ABC algorithm named as OGABC based on opposition-based learning (OBL) and global best search equation to overcome the shortcomings of the slow convergence rate and sinking into local optima in the process of inversion of atmospheric duct. Taking the inversion of the surface duct using refractivity from clutter (RFC) technique as an example to validate the performance of the proposed OGABC, the inversion results are compared with those of the modified invasive weed optimization (MIWO) and ABC. The radar sea clutter power calculated by parabolic equation method using the simulated and measured refractivity profile is utilized to carry out the inversion of the surface duct, respectively. The comparative investigation results indicate that the performance of OGABC is superior to that of MIWO and ABC in terms of stability, accuracy, and convergence rate during the process of inversion.
A New Adaptive Hungarian Mating Scheme in Genetic Algorithms
Authors: Jung Chanju , Kim Yong-Hyuk , Yoon Yourim , Moon Byung-Ro
Published: April 2016

In genetic algorithms, selection or mating scheme is one of the important operations. In this paper, we suggest an adaptive mating scheme using previously suggested Hungarian mating schemes. Hungarian mating schemes consist of maximizing the sum of mating distances, minimizing the sum, and random matching. We propose an algorithm to elect one of these Hungarian mating schemes. Every mated pair of solutions has to vote for the next generation mating scheme. The distance between parents and the distance between parent and offspring are considered when they vote. Well-known combinatorial optimization problems, the traveling salesperson problem, and the graph bisection problem are used for the test bed of our method. Our adaptive strategy showed better results than not only pure and previous hybrid schemes but also existing distance-based mating schemes.
Detecting and Mitigating Smart Insider Jamming Attacks in MANETs Using Reputation-Based Coalition Game
Authors: Al Sharah Ashraf , Oyedare Taiwo , Shetty Sachin
Published: April 2016

Security in mobile ad hoc networks (MANETs) is challenging due to the ability of adversaries to gather necessary intelligence to launch insider jamming attacks. The solutions to prevent external attacks on MANET are not applicable for defense against insider jamming attacks. There is a need for a formal framework to characterize the information required by adversaries to launch insider jamming attacks. In this paper, we propose a novel reputation-based coalition game in MANETs to detect and mitigate insider jamming attacks. Since there is no centralized controller in MANETs, the nodes rely heavily on availability of transmission rates and a reputation for each individual node in the coalition to detect the presence of internal jamming node. The nodes will form a stable grand coalition in order to make a strategic security defense decision, maintain the grand coalition based on node reputation, and exclude any malicious node based on reputation value. Simulation results show that our approach provides a framework to quantify information needed by adversaries to launch insider attacks. The proposed approach will improve MANET’s defense against insider attacks, while also reducing incorrect classification of legitimate nodes as jammers.
Ultra-High and Near-Zero Refractive Indices of Magnetron Sputtered Thin-Film Metamaterials Based on TixOy
Authors: Jokanović Vukoman , Čolović Božana , Nenadović Miloš , Trajkovska Petkoska Anka , Mitrić Miodrag , Jokanović Bojan , Nasov Ilija
Published: April 2016

Metamaterials based onTixOywith ultra-high and near-zero refractive indices were obtained by DC magnetron sputtering. The data on refractive indices, extinction coefficients, film thickness, and band gaps, obtained by spectroscopic ellipsometry, showed very high potential of these materials as metamaterials. Phase analysis performed by XRD revealed the presence of titanium phases with lower titanium oxidation states resulting from high concentration of oxygen vacancies, which are crucial for such extraordinary jumps and drops of refractive indices. Numerous band gaps for direct and indirect electron transitions additionally confirmed unique properties of these materials.
The Segmentation of Wear Particles Images UsingJ-Segmentation Algorithm
Authors: Liu Hong , Wei Haijun , Wei Lidui , Li Jingming , Yang Zhiyuan
Published: April 2016

This study aims to use a JSEG algorithm to segment the wear particle’s image. Wear particles provide detailed information about the wear processes taking place between mechanical components. Autosegmentation of their images is key to intelligent classification system. This study examined whether this algorithm can be used in particles’ image segmentation. Different scales have been tested. Compared with traditional thresholding along with edge detector, the JSEG algorithm showed promising result. It offers a relatively higher accuracy and can be used on color image instead of gray image with little computing complexity. A conclusion can be drawn that the JSEG method is suited for imaged wear particle segmentation and can be put into practical use in wear particle’s identification system.
Characteristics of Relocated Quiet Zones Using Virtual Microphone Algorithm in an Active Headrest System
Authors: Ryu Seokhoon , Lee Young-Sup
Published: April 2016

This study displays theoretical and experimental investigation on the characteristics of the relocated zone of quiet by a virtual microphone (VM) based filtered-x LMS (FxLMS) algorithm which can be embedded in a real-time digital controller for an active headrest system. The attenuation changes at the relocated zones of quiet by the variation of the distance between the ear and the error microphone are mainly examined. An active headrest system was implemented for the control experiment at a chair and consists of two (left and right) secondary loudspeakers, two error microphones, two observer microphones at ear positions in a HATS, and other electronics including a dSPACE 1401 controller. The VM based FxLMS algorithm achieved an attenuation of about 22 dB in the control experiment against a narrowband primary noise by the variation of the distance between the ear and the error microphone. The important factors for the algorithm are discussed as well.
Real-Time Implementation of Islanded Microgrid for Remote Areas
Authors: Jain Monika , Gupta Sushma , Masand Deepika , Agnihotri Gayatri , Jain Shailendra
Published: April 2016

Islanding is a condition in which a microgrid or a portion of power grid, consisting of distributed generation (DG) sources, converter, and load, gets disconnected from the utility grid. Under this condition the DG sources in a microgrid must switch to a voltage control mode, in order to provide constant voltage to local loads. In grid connected mode, the microgrid works as current controller and injects power to the main grid, depending on the power generation and local load with suitable market policies. Providing constant voltage at a stable frequency with proper synchronization amongst each DG in a microgrid is a challenge. The complexity of such grid requires careful study and analysis before actual implementation. These challenges of microgrid are addressed using real time OPAL-RT simulation technology. Thus the paper describes an islanded microgrid with master slave controller for power balance, voltage/frequency regulation, and synchronization. Based on an advanced real-time platform named Real-Time Laboratory (RT-LAB), the impacts of the micro sources, load, and converters in an islanded microgrid is studied in this paper. The effectiveness of the proposed controller is analyzed through experimental results under balanced/unbalanced nonlinear loads condition.
Seven-Year Follow-Up of Peutz-Jeghers Syndrome
Authors: Mozaffari Hamid Reza , Rezaei Fetemeh , Sharifi Roohollah , Mirbahari S. Ghasem
Published: April 2016

One of the clinicopathological criteria for diagnosing Peutz-Jeghers syndrome (PJS) is mucocutaneous pigmentation. We present a 57-year-old Iranian female patient with diffuse pigmentation in buccal and labial mucosa. The first colonoscopy revealed one 0.5 cm rectal polyp. However surveillance colonoscopies over a 7-year polyp showed over 100 colorectal polyps.
Interaction of Magnetic Field and Nonlinear Convection in the Stagnation Point Flow over a Shrinking Sheet
Authors: Kumar Rakesh , Sood Shilpa
Published: April 2016

The steady two-dimensional boundary layer stagnation point flow due to a shrinking sheet is analyzed. The combined effects of magnetic field and nonlinear convection are taken into account. The governing equations for the flow are modeled and then simplified using the similarity transformation and boundary layer approach. The numerical solution of the reduced equations is obtained by the second-order finite difference scheme also known as Keller box method. The influence of the pertinent parameters of the problem on velocity and temperature profiles, skin friction, and sheet temperature gradient are presented through the graphs and tables and discussed. The magnetic field and nonlinear convection parameters significantly enhance the solution range.