bluuebunny/crossref_metadata_2025 huggingface dataset:
Failure Analysis of Fractured S135 Grade Drill Pipe
Authors: Lu Cai Hong , Liu Yong Gang , Wang Xin Hu , Li Fang Po , Qu Ting Ting
Published: October 2013

The fractured drill pipe was investigated by means of non-destructive testing, chemical composition analysis, optical microscope, material property testing machine and SEM with EDS. The results showed that fracture of drill pipe body was hydrogen sulfide stress corrosion cracking. High strength, high hardness, and stress corrosion sensitivity of the drill pipe material were important reasons leading to failure.
Study on the Effects of Nitrogen Pollution to the Soil and Groundwater
Authors: Lu Xiao Hui , Wang Yang
Published: October 2013

Xuzhou city lies on the north of Jiangsu province, which geological conditions are complex, water resources are deficient and environment is vulnerable. At present, water pollution in Kui river area is very serious; Kui River nitrogen pollution had affected Coastal soil and chemical environment of groundwater. The monitoring sections are elected in the seriously polluted river, and downstream at the banks of river decorates with six monitoring sections. Each section from the river bank of 50m, 100m, 200m, 500m, 1000m, 1500m is arranged of monitoring points respectively, and each monitoring point is monitored for sampling test at different depths. The monitoring results of surface water showed that the content of ammonia-nitrite-nitrate was a decreasing trend along the flow direction. The nitrate nitrogen content would decrease further in December while the ammonium nitrogen content was on the rise, showing that the supplement of nitrogen pollution resources was still insufficient when the denitrification was stronger. The content of ammonium and nitrate nitrogen in soil was higher, and had some regular change features with the change of depth.
Evaluation of the Influence of the Chlorophyll Fluorescence of Plant after Fumigated with Ozone Gas
Authors: Chung Chung Yi , Chung Pei Ling , Gau Hwa Sheng , Liao Shao Wei , Lai Wen Liang
Published: October 2013

This study utilized a custom-made fumigation chamber to evaluate the chlorophyll fluorescence of 7 species sidewalk trees with 60 ppb O3for 10 days. The results showed that during the fumigation period, the plants showed a noticeable variation. At the first 6 days fumigation, the chlorophyll fluorescence of all tested trees showed a stable status with the values over 0.75. As of the 7thdays fumigation, the chlorophyll fluorescence of tested trees was lower than 0.75 exceptCerbera manghasandNageia nagi. After 9 days fumigation, the chlorophyll fluorescence values for all tested trees are significantly lower than before. Among all tested trees, the chlorophyll fluorescence ofPalaquium formosanumhad the most variant than before fumigation experiment, the next wasTournefortia argentea, than theCerbera manghas,Terminalia catappa,Aglaia formosana,Millettia pinnataandNageia nagiin series.
Heat Generation Characteristics and Heat Dissipation Experiment of CPU Chip
Authors: Li Mao De , Wei Shuai
Published: October 2013

With the development of the CPU integration, providing effective heat removal solutions for chip is an important research. This article analyses the reason of chip overheat and different adopted techniques in chip heat dissipation and commits itself to take the variation of the operating conditions into account to obtain the overall temperature rising curve based on a simplified thermal model. And then it utilizes heating plate as constant heat source to simulate CPU heating. Under the power of 20W, 30W and 40W, we compare five kinds of fan-cooled radiators in order to provide the experimental statistics for the further design and theoretical analysis.
Quenching Circuit of Avalanche Diodes for Single Photon Detection
Authors: Xu Qing Yao , Wang Hong Pei , Hu Xiang Chao , Qian Hai , Peng Ying Cheng , Ren Xiao Hang , Li Yan Jie
Published: October 2013

To reduce the afterpulsing in single photon detection based on avalanche diodes, an advanced passive quenching circuit for operation in free-running mode is developed. The measurement setup is designed. The dark count rate (DCR) and afterpulsing of Single photon avalanche diodes (SPADs) are measured. The results show that the new passive quenching circuit has a better afterpulsing performance compared to traditional circuits.
A Method of Determining Multiple-Targets Interception Based on Traversing Points
Authors: Li Yuan Fei , Zhang Ya Sheng
Published: October 2013

Space attack-defense confrontation is the commanding height in modern warfare. This paper takes space platform as research object and tries to solve problems such as space non-coplanar, large energy consumption of multiple-targets orbit interception and long interception time. Firstly, a design energy-optimal method of orbit interception based on Traversing Points is proposed. Secondly, the optimal design model of orbital interception is established. Finally, we take space platform interception of three targets in low earth orbit as an example and STK simulations analysis is carried out to verify the effectiveness of the proposed method. The research provides a theoretical basis for analysing non-coplanar and multi-targets interception strategy.
Based on the Theory of the Miner Fatigue Damage of Fuzziness Analysis and Mathematical Modeling
Authors: Liu Xiao Fen , Wu Zhuo , Song Ming , Zheng Min
Published: October 2013

In this paper, based on Miner rule, fuzzy analysis was carried out on predicting the fatigue damage, and mathematical model was established by considering loading sequence and interaction between loads and introducing the membership function. The analysis results show that the predicting fatigue life via the "Blurredregion" extension methods is closer to the test results.
Kinematics Analysis for Pavement Accelerated Loading Testing System
Authors: Guo Xing Yu , Guan Zhi Guang , Zhang Peng
Published: October 2013

In order to study the reasonable structure and failure mechanism of the road surface, reduce construction and maintenance costs, optimize road performance, kinematics analysis for the loading car virtual prototype is researched. The simulation results show that the velocity and acceleration of the loading car are all changed. And a delay time is needed in order to get stable loading, which can provide a theoretical basis for pavement accelerated loading testing system design.
Modeling of Multi-Agents' Coordination
Authors: Zhang Mei , Wen Jing Hua , Fan Yong Long
Published: October 2013

It takes cooperation among multi-user in virtual geographic environment (VGE) based on Multi-Agent System (MAS) in the centralized system as researched object. Then we detailed analyze and research arithmetic of collectivistic operating behaviour learning of Multi-Agent based on Genetic Algorithm (GA). Finally we design an example which shows how 3 evolutional Agents cooperate to complete the task of colony pushing cylinder box.
Network Analysis and Impedance Matching Methods for Wireless Power Transfer via Coupled Magnetic Resonances
Authors: Luo Yan Ting , Yang Yong Min , Chen Zhong Sheng
Published: October 2013

Wireless power transfer (WPT) via coupled magnetic resonances has received much attention owing to its high power transmission efficiency at mid-range distance in recent years. In this paper, a novel network method is used to analyze the WPT system. A two-port network model of the system is built and the ABCD parameters of the model are innovatively used to characterize the system. Then the power transmission efficiency is analyzed at different transmission distance. To improve the power transmission efficiency, an impedance matching method is proposed based on the network analysis of the system. In the end, its feasibility is testified by a case study. The results demonstrate that the maximum power transmission efficiency can be achieved by using the impedance matching method proposed in this paper.
Research on the Natural Frequency Solving Method of the Simply Supported Beam Bridge with Cracks
Authors: Sun Ping Yi , Wang Yan Hua , Liu Han Bing , Tan Guo Jin
Published: October 2013

Two kinds of natural frequency solution methods for the simply supported beam bridge with cracks are presented respectively based on the Bernoulli-Euler beam model and the finite element approach. Multiple groups of crack damages are supposed on the experimental simply supported steel I-beam, and the natural frequencies of the experimental beam are measured in all the crack cases. By comparing the calculated natural frequencies respectively obtained by the above two methods with the experimental values, the characteristics of the two kinds of natural frequency solving methods are evaluated.
Study on Synthesis and Properties of Spinel Structure Li1+xMn2-xO4 for Lithium Ion-Sieve Precursor
Authors: Song Shi Tao , Wu Su Xia , Peng You Shun , Zheng Xue Fang , Lian Qi
Published: October 2013

Spinel structure Li1+xMn2-xO4 materials for lithium ion-sieve precursor were synthesized by high temperature solid state method and their adsorption properties were improved by adjusting the molar ratio of lithium to manganese. The structure, morphology and adsorption performance of the synthetic samples were characterized by XRD, SEM, and lithium ion adsorption experiments. The influences of pH value and adsorption time on adsorption capacity were discussed. The results showed that the Li1.3Mn1.7O4 material had the largest adsorption capacity and it reached up to 24.06 mg·g-1 when the pH value was 12 and the adsorption time was 10 h.
Effects of Weld Heat Input on Microstructures of Coarse Grain Heat-Affected Zone of Bearing-Nb HF Steel Plate
Authors: Zhao Yi Sheng , Zhang Xin Ming
Published: October 2013

Effects of weld heat input on microstructures of coarse grain heat-affected zone (CGHAZ) were taken into account for bearing-Nb HF steel plate. For weld heat input from 12 to 20KJ/cm, grain boundary ferrite, degenerate pearlite and acicular ferrite are produced for steel plate with the Si/Mn ratio of 0.26. For higher input, bainite phase is found at the center of specimens. However, for the steel with the Si/Mn ratio of 6.2, granular bainite is dominant at weld heat input from 12 to 20KJ/cm. For further improving the weld heat input to 24KJ/cm, bainite nucleation at prior austenite grain boundaries is suppressed in the considered steel. Nb addition has obvious influences on microstructure.
Design of Bilateral Tracing Intelligent Car Based on Photoelectric Sensors
Authors: Ren Ren Kai , Zhang Ya Wei
Published: October 2013

This paper presents the design of a bilateral tracing intelligent car based on photoelectric sensors. The control system selects the 16-bit MC9S12XS128 microprocessor as the core controller; employs laser tube and receiving tube to detect the location and movement direction; applies fuzzy self-adaptive PD controller to control the servos; makes use of photoelectric encoder to examine the cars speed. Experimental results indicate that the intelligent car can run along the track steadily and rapidly.
Relative Distance-Based Forwarding Protocol for Underwater Wireless Sensor Networks
Authors: Li Zong Lin , Yao Nian Min , Gao Qin
Published: October 2013

Underwater wireless sensor networks (UWSNs) have attracted significant research attention recently from both industry and academia. Due to the significantly differences from terrestrial wireless sensor networks, including slow propagation speed, high end-to-end delay, low available bandwidth, variable link quality and energy constraint, designing an efficient routing protocol for the underwater sensor networks is challenging. In this paper we devise a relative distance-based forwarding (RDBF) routing protocol, which always try to send the packets along an optimized path without constructing a communication path previously. To limit the scope of candidate forwarders and find the optimal relay, we utilize a fitness factor to measure and judge the degree of appropriateness for a node to forward the packets.
Measurement Method Research on Inertial Parameters of Motor Assembly
Authors: Sun Ling , Yu Peng , Zhang Tong
Published: October 2013

Inertial parameters of the motor assembly include its mass, CM (center of mass) position, moment of inertia and product of inertia. Taking one vehicle drive motor as the research object, its mass and CM position are measured by using weight method and moment balance method respectively. Its moment of inertia and product of inertia are measured by using three-wire pendulum. On the basis of analyzing the test error, this paper proposed specific measures to reduce the test error.
Conceptual Multidisciplinary Parameterized Design and Simulation of Three Axis Servo System
Authors: Lu Zhong Yue , Zhang Zhi Xiong , Shao Xue Hui , Xu Li
Published: October 2013

To improve the efficiency of design and simulation of a three axis servo system, puts forward the concept of a multidisciplinary parameterization design method. Based on dynamics analysis software ADAMS to build a three axis servo mechanism of the virtual prototype; Based on MATLAB/SIMULINK modeling servo control system; Based on GUI simulation compile the parameters input interface; Through simulation circuit and application example of the proposed model, application of multidisciplinary parameterized simulation to guide the design of mechanical and control system was introduced in detail ;Verified the method can obviously improve the efficiency of a three axis servo systems design and simulation.
Maintenance Strategy Optimization Method Based on Semi-Markov Process for Hybrid Flow Shop
Authors: Huo Lin , Wang Zi Li , Lv Chuan , Zhou Dong
Published: October 2013

As availability of HFS is a basic indicator to measure the degree of usability, optimal maintenance strategy with maximum availability and cost constraints can provide a better platform for HFS scheduling. So this paper proposes a Semi-Markov Process (SMP) based availability model here focused on general maintenance strategy with machines life time distribution and maintenance time distribution. Then the maintainability parameters optimization method with total cost constrains is achieved based on the availability model. Furthermore, the proposed optimization method is applied to a two-stage HFS and showed to be effective.
Virtual Maintenance Training System of Airborne Electronic Equipment
Authors: Zou Zhi Bin , Wu Jiang Biao , Ma Ming
Published: October 2013

Maintenance training of airborne electronic equipment is the guarantee of working orderly for the airplane. The best choice of maintenance training is using real electronic equipment so that high training cost and potential damage to normally working equipment exist. To reduce the training cost and risk, a virtual maintenance training system of airborne electronic equipment is designed and implemented using virtual reality technology. The architecture of this virtual training system is given. In this architecture, three-dimensional model of electronic equipment is implemented by 3DMax software, and GL Studio software is used to create the operation response of all manipulations. Signal models based on multi signals flaw graph is used to simulate various faults. Finally, the application of this virtual maintenance training system in daily aircraft maintenance training show good training efficiency.
A Review of Diffusion and Interfacial Reactions in Sandwich Thin-Film Couples
Authors: Ghorai Amitava , Roy D.
Published: October 2013

In this paper different techniques for sandwich thin film production, characterization and interfacial reactions have been reviewed in order to understand the kinetic behaviour in the above systems. The contact and composite resistance measurements are the indirect methods for this purpose, while X-ray diffraction studies (XRD), Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), Rutherford backscattering (RBS), Auger electron spectroscopy (AES), secondary ion mass spectrometry (SIMS), ion sputtering spectrometry (ISS), X-ray photoelectron spectroscopy (XPS) which is also referred to as electron spectroscopy for chemical analysis (ESCA) and atomic force microscopy (AFM) are some of the direct methods. Trends indicate that interfacial reactions start at room temperature.
Correlation Coefficient between Vickers Hardness and Nuclear Technique
Authors: Badawi Emad A. , Abdel-Rahman M.A. , El-Nahhas Alaa El-Deen A.
Published: October 2013

The aim of this work is to establish a correlation coefficient between the positron annihilation lifetime technique (PALS) and the Vickers hardness for the heat treatable aluminum alloys (6066, 6063).The potential of positron annihilation spectroscopy in the study of light alloys is illustrated with special regards to age hardening, severe plastic deformation, annealing and quenching in aluminum alloys. Vickers hardness is the standard method for measuring the hardness of metals, particularly those with extremely hard surfaces. Accordingly, a correlation coefficient of 90 % between τ and Hv is obtained. This correlation can help us to explain many behaviors of these alloys under deferent conditions.
Quasicrystalline Phase Formation in High Frequency Induction Melted Al80Cu14Fe6 Alloy
Authors: Boularas H. , Debili M.Y.
Published: October 2013

Structural characteristics and thermal behavior of the conventionally solidified Al80Cu14Fe6, was investigated by X-ray diffraction, optical microscopy, and differential thermal analysis techniques. It was found that the formation of quasi crystalline phase occurs after annealing for relatively low temperature (500°C) during a short time.
Thermal Desorption of Hydrogen from AISI 316L Stainless Steel and Pure Nickel
Authors: Todoshchenko Olga , Yagodzinskyy Yuriy , Hänninen Hannu
Published: October 2013

Hydrogen diffusion and trapping in AISI 316L stainless steel and pure nickel are studied with thermal desorption spectroscopy method. Specific features of hydrogen uptake and desorption for a multi-component alloy in comparison with that for pure metal and the effects of hydrogen concentration profile after electrochemical charging on the hydrogen desorption are discussed. It is shown that hydrogen diffusion and trapping in multi-component alloy are caused by the specific atomic distribution of hydrogen in the crystal lattice of alloy.
Empirical Mode Decomposition of Vibration Signal for Detection of Local Disturbances in Planetary Gearbox Used in Heavy Machinery System
Authors: Dybała Jacek , Zimroz Radoslaw
Published: October 2013

In rotating machinery, the detection of local damage is one of the most important issues. This kind of change of technical condition produce local disturbance according to temporal (local) change of stiffness of kinematic pair (tooth-tooth contact, rolling element-outer/inner race etc). In many practical, i.e. industrial cases, vibration signature of such change is weak in sense of produced energy, so consequently, completely masked by other vibration sources in machine. The general concept of signal processing for local damage detection is to use so called signal enhancement, i.e. a kind of tool that may improve signal to noise ratio. One may find many approaches used in the literature. Most of them use signal filtering (classical, adaptive and optimal filters), decomposition (wavelets) or extraction (blind source separation). Empirical Mode Decomposition (EMD) is one of such techniques that can be used with signal decomposition problem. In this paper, EMD will be used for vibration signal decomposition in order to extract information about local perturbation of arm (carrier) in planetary gearbox used in heavy mining machine, i.e. bucket wheel excavator. As a result of application of EMD, one may obtain several time series with different properties of sub-signal. Due to predefined task, namely local disturbance detection, several criteria have been investigated in order to select the most informative empirical mode. First criterion was kurtosis calculated for every mode with very simple decision rule (max kurtosis is the best). It was found that such approach is not optimal due to some random impulses that are not related to damage. To improve results, it is proposed to combine envelope spectrum and kurtosis. If envelope spectrum contains family of components related to arm (carrier) shaft frequency and signal is spiky (kurtosis is high) result of EMD for given mode is optimal in sense of carried information. However, in this approach decision was made based on visual inspection of the envelope spectra of each mode, which is non-effective way. Finally two parameters have been proposed: 1) Pearson correlation coefficient of an empirical mode and the empirically determined local mean of original signal; 2) a relative power of an empirical mode.
New Focus on Gearbox Condition Monitoring for Failure Prevention Technology
Authors: Bartelmus Walter
Published: October 2013

Condition monitoring is a tool for detection of faults and failure prevention. Fault andfailure are regarded as inevitable during the machine operation as the process of wear and theprocess of degradation. The question is, if one can influence the wear and degradation process,using condition monitoring. The paper will present technology which demonstrates that the use ofthe proper method can influence the wear and machine degradation process, using proper conditionmonitoring techniques and knowing scenarios of wear and degradation process. In the discussionpresented in the paper as a prerequisite has been taken that machinery works in severe dustyenvironment and varying operation conditions. It has been pointed that degradation process is notjust simply development of one fault. Most research for developing technology for conditionmonitoring is concentrated on one fault development. If one considers condition monitoring for acrack and brakeage of a tooth in gearbox, one should take in consideration that tooth crack andbrakeage is the result of several events, like rolling elements bearing frictional wear, which causesecondary misalignment of shaft and gears. The frictional wear is caused by dust particles whichget into oil from the environment in which a gearbox is operating. To avoid an influence ofcontaminated oil, contamination proactive technology should be used for the assessment of thedegree of contamination and the decision on oil purification or change should be taken. The wholeprocess connected with a gearbox condition change (wear and degradation process) shall bedescribed in the paper. The oil purification or its replacement extends the live of gearboxes butlong live of a gearbox, even with very little contamination causes some frictional wear of bearingsand finally secondary misalignment. To avoid further development of degradation process propertechnology should be used. There is a need to measure the degree of misalignment and makedecision on bearings replacement, in order to avoid further gearbox degradation, like teeth scuffingwhich may leads to crack initiation.
Online Fault Diagnosis of Automotive Powernets by Kalman Filtering
Authors: Puchalski Andrzej , Komorska Iwona
Published: October 2013

The paper discusses real-time parameters identification methods of the mechatronics subsystems in the automobile for the on-board diagnostics and adaptive control. In particular, the significant increase in electric power consumption requires predictive management strategy that detects critical loads situations. To accomplish these goals we investigated diverse vehicular powernet circuits and devices. This paper presents the results of the extended Kalman filtering algorithm for the parameters estimation of the wiring harness of a cooling fan system.
Power Plant Remaining Life Evaluation
Authors: Furtado Heloisa , Santos Fernanda , Cardoso Bruno , Matt Carlos Frederico , de Almeida Luiz Henrique
Published: October 2013

The present paper describes the development of a monitoring, analysis and diagnosis system of power plant equipments based on strain measurements. The objective is to help companies increase availability and reduce maintenance costs. The aim is the integrity evaluation of a main steam and a hot reheat steam piping through inspection, strain monitoring and computational diagnosis. The benefits are, among others, reduction in the uncertainty of the remaining life prediction and reduction of work, through process automation and integration and real time monitoring (through the Internet) of the operational condition of the equipment. Thus, greater confidence and availability of the monitored generating unit is sought as well as cost reduction as a consequence of reduced frequency of unnecessary unit stops and greater speed in decision making due to more precise follow up of the operational condition of the target-equipment and of its remaining life.
Theoretical and Experimental Investigations of Oil-Free Bearings and their Application in Diagnostics of High-Speed Turbomachinery
Authors: Kozanecki Zbigniew , Tkacz Eliza , Łagodziński Jakub , Miazga Kacper
Published: October 2013

In order to reduce the risk of failures, the optimal design selection from the viewpoint of machine reliability must be conducted. Therefore, one should analyze thoroughly the dynamics of the rotor-bearing-casing system in the whole operating range of the machine. The rotating system presented in the paper is supported in non-conventional bearings. The actual study consists in the investigation of new coating materials in the bearing design and the improvement in rotating system dynamics to increase the total efficiency, maintain the cleanness of the working medium and ensure operation of bearings in wide temperature ranges. Despite many advantages, air-foil bearings meet problems of friction and wear in critical moments of their operation, furthermore their complete theoretical model is difficult to establish. Different modeling theories of such bearing dynamic characteristics are shortly described. The current tendency in numerical and experimental methods for diagnostics of rotor support systems of low power rotating machinery is outlined.
Use of Neural Networks in Diagnostics of Rolling-Element Bearing of the Induction Motor
Authors: Swędrowski Leon , Duzinkiewicz Kazimierz , Grochowski Michał , Rutkowski Tomasz
Published: October 2013

Bearing defect is statistically the most frequent cause of an induction motor fault. The research described in the paper utilized the phenomenon of the current change in the induction motor with bearing defect. Methods based on the analysis of the supplying current are particularly useful when it is impossible to install diagnostic devices directly on the motor. The presented method of rolling-element bearing diagnostics used indirect transformation, namely Clark transformation. It determines the vector of the spatial stator current based on instantaneous current measurements of the induction motor supply phases current. The analysis of the processed measurement data used multilayered, one-directional neural networks, which are particularly attractive due to their nonlinear structure and ability to learn. During the research 40 bearings: undamaged, with damages of three types and various degrees of fault extent, were used. The conducted research proves the efficiency of neural networks for detection and recognition of faults in induction motor bearings. In case of tests of the unknown state bearings, an efficiency approach to failure detection equaled 77%.
Whose Stereotypes and Racial Myths? The National Urban League and the 1950s Roots of Color-Blind Adoption Policy
Authors: Spence Matine T.
Published: October 2013

This study finds that the National Urban League, in the middle decades of the 20th century, led widespread efforts by child welfare agencies to recruit adoptive African American homes for children in black communities. Such findings are contrary to the predominant adoption historiography, which portrays a "pervasive neglect of black dependent children by the adoption community" until the appearance of interracial adoption for black children in the mid-1960s. However, despite these early activities of the National Urban League, leaders hoped for a fully integrated society characterized by assimilation. This led top leaders in the National Urban League adoption work to shift emphasis to interracial adoption just as a large number of minority adoptive-home recruitment projects were being met with overly strict standards for appropriate adoptive parents-which reflected the characteristics of the white middle-class couple. Minority-home recruitment efforts and liberalization of social work adoption standards were, thus, abandoned by the National Urban League. It used its influence on the Child Welfare League of America during the 1960s solely for the purpose of promoting color-blind adoption policy. It created targeted messages to social workers that encouraged them to approve transracial adoptions of black children by white parents instead of same-race adoptions into black American families. Minority adoptive-home recruitment campaigns were allowed to fade away
Multidimensional Approaches to Examining Gender and Racial/Ethnic Stratification in Health
Authors: Brown Tyson H. , Hargrove Taylor W.
Published: October 2013

Extant research on health disparities has traditionally employed a unidimensional approach to stratification, focusing on gender and racial/ethnic inequality separately. Such studies implicitly assume that gender inequality is monolithic across racial/ethnic lines and that racial/ethnic stratification is similar for women and men. While informative, these traditional, unidimensional approaches artificially decouple gender and racial/ethnic inequality and, consequently, may obscure the gender-race/ethnicity-health relationship, thus limiting our understanding of the unique health experiences of women of color. This study extends prior research by using multidimensional approaches to examine whether gender and racial stratification combine in an additive or multiplicative fashion to shape functional health, consistent with double-jeopardy and intersectionality hypotheses, respectively. In addition, this study investigates the extent to which group differences in socioeconomic status (SES), health behaviors, and medical care explain gender-racial/ethnic disparities in health. We use data from the Health and Retirement Study, a nationally representative sample of older adults, to address these questions among a diverse sample of black, white, and Mexican American men and women. Results reveal that women of color have worse functional health than all other gender-racial/ethnic groups and that the joint impacts of gender and racial/ethnic oppression on functional health are additive among Mexican Americans and multiplicative among blacks. We find that multidimensional approaches-namely, double-jeopardy and intersectionality-as well as examination of various potential mediators of health disparities provide a better understanding of how health is shaped by multiple social locations.
Inovação e Gestão de Projetos: Os “Fins” Justificam os “Meios”
Authors: Da Silva Edson Coutinho , Gil Antonio Carlos
Published: October 2013

O advento da globalização, a evolução dos meios de comunicação, aliados ao progresso dos recursos de tecnologia da informação, impuseram uma dinâmica de aceleração progressiva aos processos de mudança em geral. Este fenômeno tem feito com que cada vez mais as organizações busquem e renovem seus instrumentos de gestão, em prol aprimoramento de atividades e processos que lhes garantam a inovação de um determinado produto e/ou serviço. Ao mesmo tempo em que a globalização torna os mercados mais competitivos, o “cliente moderno” passa a ter mais opções e a ser mais exigente. É preciso que as organizações se adaptem a este novo cenário, de forma a cada vez mais oferecerem produtos e/ou serviços com maior qualidade e a preços mais competitivos. Dentre as medidas que podem ser tomadas para alcançar este objetivo, encontra-se a prática de gerenciar projetos de uma forma mais profissional e planejada. E para auxiliar os gerentes nesta prática, um campo da administração está em ascensão: a Gestão de Projetos a partir da metodologia do Project Management Institute (PMI). Com as constantes fusões, aquisições e, consequentemente, diversificações dos negócios das organizações no atual mundo globalizado, o gerenciamento de projetos pode ser uma opção para que as organizações superem seus desafios e obstáculos relacionados à inovação e, ao mesmo tempo, alcancem seus objetivos de resultados e crescimentos almejados.DOI:10.5585/gep.v4i1.75
Identificação e Análise de Fatores Críticos de Sucesso em Projetos
Authors: Vezzoni Guilherme , Júnior Antônio Carlos Pacagnella , Junior Ailton Luiz Banzi , Da Silva Sérgio Luis
Published: October 2013

A proposta deste trabalho é compreender as relações entre fatores críticos de sucesso e sua influência no desempenho de projetos. Para alcançar este objetivo foram utilizados dados coletados por um survey que resultou em 216 observações válidas. A pesquisa é caracterizada por uma abordagem quantitativa, com caráter descritivo e explicativo, amostragem por julgamento e como técnica a regressão logística. Os resultados obtidos mostram que a comunicação eficiente, o empowerment, o gerenciamento de mudanças, o gerenciamento de requisitos, a preparação para enfrentar riscos e o suporte da alta administração aumentam a probabilidade dos projetos atingirem o sucesso.DOI:10.5585/gep.v4i1.83
Des effets d’un entraînement métacognitif sur les stratégies et les performances en compréhension de texte chez des adolescents présentant de sévères difficultés d’apprentissage
Authors: Berger Jean-Louis , Kipfer Nadine , Büchel Fredi P.
Published: October 2013

Les élèves présentant de sévères difficultés d’apprentissage ont souvent un déficit important dans la compréhension de texte, ceci en raison de leur manque de stratégies d’apprentissage et de connaissances métacognitives. Un programme d’entraînement des stratégies métacognitives et de prise de conscience de son propre fonctionnement cognitif a été appliqué durant 12 semaines par des enseignants dans le cadre de formations professionnelles à faible niveau d’exigences. Le présent article expose ce programme, ses conséquences sur les stratégies et les performances des élèves en compréhension de texte ainsi que les effets de transfert éloigné. Les résultats indiquent des effets bénéfiques de l’entraînement sur plusieurs mesures des stratégies et performances. Toutefois, ces effets diffèrent en fonction des aptitudes des élèves et n’apparaissent pas dans une tâche de transfert éloigné.
Multiferroic Polymer Laminate Composites Exhibiting High Magnetoelectric Response Induced by Hydrogen‐Bonding Interactions
Authors: Jin Jiezhu , Zhao Fang , Han Kuo , Haque M. A. , Dong Lijie , Wang Qing
Published: October 2013

The coupling of the magnetic, electric, and elastic properties in multiferroics creates new collective phenomena and enables next‐generation device paradigms. In this work, the hydrogen bonding interaction between hydrate salts and ferroelectric polymers is exploited in the development of high‐performance magnetoelectric (ME) polymer laminate composites. The microstructures and crystallite structures of the Al(NO3)3·9H2O doped poly(vinylidene fluoride‐co‐hexafluoropropylene), P(VDF‐HFP), are carefully studied. The effect of hydrogen bonding interaction on the polarization ordering of the ferroelectric polymers is investigated by 2D wide‐angle X‐ray diffraction, polarized Fourier transform infrared spectra, and dielectric spectra at varied frequencies and temperatures. It is found that hydrogen bond not only promotes the formation of the polar crystallite phase but also improves the polarization ordering in the ferroelectric polymer, which subsequently increases the remnant polarization of the polymers as verified in the polarization‐electric field loop measurements. These entail marked improvement in the ME voltage coefficients (αME) of the resulting polymer laminate composites based on ferromagnetic Metglas relative to analogous composites. The composite exhibits a state‐of‐the‐art αME value of 20 V cm‐1 Oe under a dc magnetic field of ≈4 Oe and a colossal αME of 320 V cm‐1 Oe at a frequency of 68 kHz.
In Situ Functionalization of Stable 3D Nest‐Like Networks in Confined Channels for Microfluidic Enrichment and Detection
Authors: Wang Gang , Shi Guoying , Wang Hongzhi , Zhang Qinghong , Li Yaogang
Published: October 2013

Construction of stable 3D networks directly on the inner wall of microchannels is of great importance for various microfluidic applications. 3D nest‐like networks with large contact surface areas and excellent structural stability are fabricated via a facile, template‐free, continuous fluid construction process directly in confined microchannels. Bovine serum albumin (BSA) is chosen as a model albumin to test the adsorption of the network modified microchannel to the target albumin. The high structural stability of the networks is confirmed both by finite element analysis (FEA) simulation and recycling experiments for BSA enrichment. ZnS shells are fabricated based on the original 3D Zn(OH)F networks through in situ chemical conversion. The nest‐like networks decorated with Ag nanoparticles (NPs) serve as 3D substrates for surface‐enhanced Raman scattering (SERS), exhibiting excellent sensitivity for rapid detection of trace 10−12 mol L−1 (1 pM) BSA. Three different gap sizes between Ag NPs in the 3D geometry create a large number of SERS hot spots that contribute to the high sensitivity of the networks. Furthermore, a transparent, flexible, microfluidic device containing the 3D nest‐like structures exhibits excellent recyclability and flexible stability for trace BSA enrichment, showing potential for application in online SERS detection.
Biodegradability of PP/PHBV (70/30) Blend Films
Authors: GonÇalves Suely Patricia Costa , Franchetti Sandra Mara Martins
Published: October 2013

This study aimed to investigate the biodegradation of polypropylene/poly(hydroxybutyrate‐co‐hydroxyvalerate) (PP/PHBV) blend (70/30, w/w) films in soil, monitoring the evolution of CO2 using the respirometric method. The polymeric films were incubated at 28°C ± 2°C for 180 days in biometer flasks, and the sequence of biodegradation percentage was PP/PHBV (70/30) > PP, that is, 15% and 0%, respectively. Fourier transform infrared spectroscopy and X‐ray diffraction measurements showed that biodegradation occurs in the blend PP/PHBV interphases. Preferentially, the microbial action occurs in the fraction of the biodegradable polymer (PHBV), and it influences the PP fraction morphology, which showed some significant changes in the monomer unit sequences and the organization of the chains. © 2013 Wiley Periodicals, Inc. Adv Polym Technol 2013, 32, 21377; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21377
Severe growth retardation, delayed bone age, and facial dysmorphism in two patients with microduplications in 2p16 → p22
Authors: Blassnig‐Ezeh Anya , Bandelier Claude , Frühmesser Anne , Revencu Nicole , Krabichler Birgit , Beauloye Véronique , Ravoet Marie , Fauth Christine , Zschocke Johannes , Simma Burkhard , Kotzot Dieter
Published: October 2013

Interstitial duplications of the short arm of chromosome 2 have been rarely described. Here, we report on two unrelated patients with overlapping chromosome 2p16 → p22 de novo microduplications found by SNP‐array analysis. The affected individuals were an 8‐year‐3‐month‐old boy with a direct duplication of approximately 14.6 Mb harboring 63 genes, and a 12‐year‐old girl with a direct duplication of around 9.6 Mb harboring 48 genes. Both patients have severe growth retardation, delayed bone age, prominent veins on trunk and extremities, total IGF1 level in the low range, mild developmental delay, and facial dysmorphism such as relative macrocephaly, a broad and prominent forehead, and a large anterior fontanelle. Comparison with patients previously reported in the literature and in the DECIPHER 5.1 and ECARUCA databases indicates a common region of interest of around 1.9 Mb responsible for most of the features. Two candidate genes (EPAS and RHOQ), may be particularly relevant for the marked growth retardation and developmental delay. © 2013 Wiley Periodicals, Inc.
Ruthenium(II) complexes of hybrid 8‐hydroxyquinoline–thiosemicarbazone ligands: synthesis, characterization and catalytic applications
Authors: Nirmala M. , Manikandan R. , Prakash G. , Viswanathamurthi P.
Published: October 2013

A series of new hexa‐coordinated ruthenium(II) hydroxyquinoline–thiosemicarbazone complexes of the type [Ru(CO)(EPh3)(B)(L)] (E = P or As; B = PPh3, AsPh3 or Py; L = hydroxyquinoline–thiosemicarbazone) were synthesized by reacting ruthenium precursor complexes [RuHCl(CO)(EPh3)2(B)] (E = P or As; B = PPh3, AsPh3 or Py) with hydroxyquinoline–thiosemicarbazone ligands in ethanol. The new complexes were characterized by analytical and spectroscopic (FT‐IR, UV–visible, NMR (1H, 13C and 31P) and fast atom bombardment (FAB)–mass spectrometric methods. Based on the spectral results, an octahedral geometry was assigned for all the complexes. The new complexes showed good catalytic activity for the conversion of aldehydes to amides in the presence of hydroxylamine hydrochloride–sodium bicarbonate and for the oxidation of alkanes into their corresponding alcohols and ketones in the presence of m‐chloroperbenzoic acid. The complexes also catalyzed the N‐alkylation of benzylamine in the presence of KOtBu in alcohol medium. Copyright © 2013 John Wiley & Sons, Ltd.
Characterization of degradation of polypropylene nonwovens irradiated by γ‐ray
Authors: Keene Brandi , Bourham Mohamed , Viswanath Vidya , Avci Huseyin , Kotek Richard
Published: October 2013

Polypropylene is a leading commercial, fiber‐forming polymer due to its low cost and potential for making high strength fibers. As the polymer of choice in the biomedical field, polypropylene contains only two elements, namely carbon and hydrogen. As a result, it is very hydrophobic and bio‐inert lacking biodegradability in the landfill. Meltblown and spunbond polypropylene nonwovens were exposed to γ‐radiation doses up to 25 kGy. The changes in morphology, chemical, thermal, and tensile properties were characterized by various analytical techniques. Following γ‐radiation, the FTIR spectrum illustrated an increase in carbonyl groups suggesting radio‐oxidation. Additionally, there was a decrease in thermal and tensile properties indicating deterioration of the polymer. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39917.
The use of environmental scanning electron microscopy for imaging the microstructure of gels for profile control and water shutoff treatments
Authors: Zhao Guang , Dai Caili , Zhao Mingwei , You Qing
Published: October 2013

The use of gel systems as profile control and water shutoff agents has become a wide practice in recent years for oil recovery applications. But few systematic studies have been carried out on the microstructure of gels. In this study, environmental scanning electron microscopy (ESEM) was employed to investigate the microstructure of gels in their natural state. It was directly observed that a three‐dimensional network structure formed in chromium or zirconium crosslinked polymer gels is the same as organic/ inorganic crosslinked gels. However, there is a dense flat structure in phenol resin crosslinked polymer gels or phenolic resin gels. The differences between the microstructures can be attributed to the different crosslinking sites and crosslinking density, and this affect the gel's stability at reservoir temperatures. In addition, this paper also introduced the crosslinking mechanism and macro‐morphology of the bulk gels. It can contribute to a better understanding of the gel's microstructure. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39946.
Detection of Enthesitis in Children With Enthesitis‐Related Arthritis: Dolorimetry Compared to Ultrasonography
Authors: Weiss Pamela F. , Chauvin Nancy A. , Klink Andrew J. , Localio Russell , Feudtner Chris , Jaramillo Diego , Colbert Robert A. , Sherry David D. , Keren Ron
Published: October 2013

Objective

To evaluate the distribution of enthesitis and the accuracy of physical examination with a dolorimeter for the detection of enthesitis in children, using ultrasound (US) assessment as the reference standard.

Methods

We performed a prospective cross‐sectional study of 30 patients with enthesitis‐related arthritis (ERA) and 30 control subjects. The following tendon insertion sites were assessed by standardized physical examination with a dolorimeter and US: common extensor on the lateral humeral epicondyle, common flexor on the medial humeral epicondyle, quadriceps at the superior patella, patellar ligament at the inferior patella, Achilles, and plantar fascia at the calcaneus.

Results

Abnormal findings on US were detected most commonly at the insertion of the quadriceps (30% [18 of 60 sites]), common extensor (12% [7 of 60]), and Achilles (10% [6 of 60]) tendons. The intrarater reliability of US (kappa statistic) was 0.78 (95% confidence interval [95% CI] 0.63–0.93), and the interrater reliability was 0.81 (95% CI 0.67–0.95). Tenderness as detected by standardized dolorimeter examination had poor positive predictive value for US‐confirmed enthesitis. In comparison to controls, patients with ERA reported more pain and had lower pain thresholds at every site, including control sites (P < 0.001 for all comparisons). The interrater reliability of dolorimeter examination for detection of enthesitis was low (κ = 0.49 [95% CI 0.33–0.65]).

Conclusion

Compared to US, standardized dolorimeter examination for the detection of enthesitis in children has poor accuracy and reliability. The decreased pain threshold of ERA patients likely contributed to the limited accuracy of the physical examination findings. Further research regarding the utility of US for identifying enthesitis at diagnosis of juvenile idiopathic arthritis, accurately predicting disease progression, and guiding therapeutic decisions is warranted.
Alginate encapsulation parameters influence the differentiation of microencapsulated embryonic stem cell aggregates
Authors: Wilson Jenna L. , Najia Mohamad Ali , Saeed Rabbia , McDevitt Todd C.
Published: October 2013

Pluripotent embryonic stem cells (ESCs) have tremendous potential as tools for regenerative medicine and drug discovery, yet the lack of processes to manufacture viable and homogenous cell populations of sufficient numbers limits the clinical translation of current and future cell therapies. Microencapsulation of ESCs within microbeads can shield cells from hydrodynamic shear forces found in bioreactor environments while allowing for sufficient diffusion of nutrients and oxygen through the encapsulation material. Despite initial studies examining alginate microbeads as a platform for stem cell expansion and directed differentiation, the impact of alginate encapsulation parameters on stem cell phenotype has not been thoroughly investigated. Therefore, the objective of this study was to systematically examine the effects of varying alginate compositions on microencapsulated ESC expansion and phenotype. Pre‐formed aggregates of murine ESCs were encapsulated in alginate microbeads composed of a high or low ratio of guluronic to mannuronic acid residues (High G and High M, respectively), with and without a poly‐L‐lysine (PLL) coating, thereby providing four distinct alginate bead compositions for analysis. Encapsulation in all alginate compositions was found to delay differentiation, with encapsulation within High G alginate yielding the least differentiated cell population. The addition of a PLL coating to the High G alginate prevented cell escape from beads for up to 14 days. Furthermore, encapsulation within High M alginate promoted differentiation toward a primitive endoderm phenotype. Taken together, the findings of this study suggest that distinct ESC expansion capacities and differentiation trajectories emerge depending on the alginate composition employed, indicating that encapsulation material physical properties can be used to control stem cell fate. Biotechnol. Bioeng. 2014;111: 618–631. © 2013 Wiley Periodicals, Inc.