bluuebunny/crossref_metadata_2025 huggingface dataset:
Modelo para estimativa do fluxo de saturação desenvolvido a partir das condições do tráfego de Brasília
Authors: Queiroz Isabela N. Fernandes de , Jacques Maria Alice Prudêncio
Published: July 2015

Dadas as dificuldades de obtenção do valor do fluxo de saturação in loco para diversas situações, ele é freqüentemente estimado a partir de modelos. Assim, esses modelos precisam refletir, da melhor forma possível, as condições locais de operação do tráfego. Este trabalho apresenta o desenvolvimento de um modelo matemático para estimativa do fluxo de saturação, por faixa de trânsito, para as condições do tráfego da cidade de Brasília. A técnica de modelagem utilizada foi à análise de regressão, e os dados para o desenvolvimento do modelo foram coletados em 20 interseções, perfazendo um total de 50 faixas de trânsito observadas. Os resultados das análises estatísticas efetuadas revelaram que o modelo é adequado para estimar o fluxo de saturação por faixa de trânsito para a cidade de Brasília. A sua utilização em outras cidades brasileiras é possível, desde que seja devidamente calibrado.
Polímeros como modificadores asfálticos
Authors: Silva Letícia SocaI da , Forte Maria Madalena de Camargo , Specht Luciano Pivoto , Ceratti Jorge Augusto
Published: July 2015

Neste trabalho foram preparadas diferentes misturas de ligante asfáltico modificado com polímeros. Foram utilizadas quatro amostras de polímeros, sendo duas de SBS, uma de SEBS e uma de Polietileno Modificado, as quais foram caracterizadas quanto a sua estrutura e propriedades térmicas através de técnicas de Ressonância Magnética Nuclear (RMN), Cromatografia por Permeação a Gel (GPC), Análise Termogravimétrica (TGA) e Calorimetria Diferencial de Varredura (DSC). O ligante modificado foi avaliado quanto a sua viscosidade, retorno elástico, comportamento reológico e estabilidade à estocagem. Foram correlacionadas a estrutura química e as transições térmicas dos polímeros com as características do ligante modificado. Os polímeros do tipo SBS foram os melhores modificadores de asfalto, quando comparado com os demais polímeros avaliados.
Programação dinâmica aplicada à alocação de recursos no transporte de cargas
Authors: Martins Lima Silva Antonio , D. Fares Gualda Nicolau
Published: July 2015

O planejamento operacional de um sistema de transporte de cargas de longa distância implica resolver um problema de otimização de rede dinâmica capacitada, visando a efetuar de forma eficaz e eficiente os movimentos das cargas, utilizando os recursos de transporte disponíveis. O presente trabalho aborda a utilização de programação dinâmica aproximada e adaptativa para solução desse tipo de problema. A metodologia de solução proposta substitui o processo de otimização global da rede por um modelo de Programação Dinâmica aplicado a cada estágio do problema; o método baseia-se em uma heurística para estimar o valor que a solução de cada estágio transfere para os estágios subseqüentes. A técnica utilizada reduz sensivelmente a quantidade de variáveis envolvidas, o que viabiliza a construção de modelos matemáticos mais realistas em um horizonte de planejamento mais amplo. São apresentados resultados de uma aplicação bem sucedida do modelo com utilização do Jensen Network Solver.
ESCOLHA DE SUB-AREA PARA IMPLANTAÇÃO DE SISTEMA DE CONTROLE SEMAFÓRICO CENTRALIZADO POR COMPUTADOR: UMA METODOLOGIA DE BAIXO CUSTO
Authors: Arruda João Bosco Furtado , Moreira Maria Elizabeth Pinheiro
Published: July 2015

Este artigo reporta uma metodologia de baixo custo para definição de sub-áreas de sistemas de controle de semáforos centralizados por computador (sistemas CTA).A utilização da técnica DELPHI de geração de consenso com um grupo de especialistas em Transportes e Uso do Solo, atuando cotidianamente na área de estudo, em conjunto com ações simplificadoras do cálculo dos benefícios advindos do controle centralizado de semáforos, bem como a utilização tanto de conceitos de vinculação de interseções interdependentes operacionalmente quanto de dados secundários da área de estudo, servem de base à definição das interseções que deverão compor o sistema CTA naquela área.O artigo ilustra uma aplicação da metodologia reportada para a definição das interseções que irão compor a primeira etapa do sistema CTA ora em projeto na cidade de Fortaleza, Ceará.

 Abstract:

This paper reports a simplified methodology built with the aim of choosing intersections which must form an Area Traffic Control (ATC) system. The intersections which make up the ATC system are determined using a DELPHI technique - with a group of traffic engineering and land-use experts working daily in the study area as well as simplifying the process of working out tile benefits of synchronization for the intersections which comprise that area. Also, concepts of intersections linkage, in terms of operational interdependence, are used conjointly with secondary data gathered in the study area to find the intersections most appropriated for the ATC system under consideration. Finally, an application of the methodology for the case of Fortaleza, a two-million inhabitants city in North-eastern Brazil, is illustrated in the paper.
Um estudo experimental sobre os afundamentos nas trilhas de rodas de pavimentos delgados com basaltos alterados
Authors: Núnez Washington Peres , Ceratti Jorge Augusto , Nakahara Suyen , Oliveira José Augusto De
Published: July 2015

Este trabalho apresenta os resultados de um estudo em verdadeira grandeza sobre afundamentos nas trilhas de roda em pavimentos delgados com bases de basaltos alterados. Um simulador linear de tráfego aplicou mais de 267.000 ciclos de carga, variáveis entre 82 e 130 kN, a cinco pistas experimentais construídas na Área de Pesquisas e Testes de Pavimentos, localizada em Porto Alegre. As estruturas ensaiadas continham bases com espessuras de 16, 21 e 32 cm, construídas com basaltos alterados de duas procedências distintas. Um total de 4.148 flechas, medidas periodicamente, forneceram um conjunto de dados consistente para uma análise estatística significativa. A evolução das flechas mostrou depender das características do tráfego e das estruturas dos pavimentos. Considerando os afundamentos nas trilhas de roda como causa da degradação de pavimentos delgados e uma flecha de 25 mm como critério de ruptura, calcularam-se fatores de equivalência de carga, através de uma análise de confiabilidade.

ABSTRACT

This paper presents the results of a study of rutting of thin pavements where weathered basalts were used as base layers. A linear traffic simulator applied more than 267,000 axle loads, ranging from 82 to 130 kN, to five full-scale test sections built in a Pavement Testing Facility located in Porto Alegre (Southern Brazil). Two different weathered basalts and three base thicknesses (16 cm; 21 cm and 32 cm) were used. A total of 4,148 measurements of rut depth, made at intervals, provided a statistically significant data set. Rutting evolution showed to depend not only on traffic characteristics but also on pavement structure. Considering rutting as major failure cause of thin pavements and a rut depth of 25 mm as terminal criterion, load equivalence factors were calculated, by means of a reliability analysis.
Modelo para formação de composições ferroviárias
Authors: Murgel Liége M. S. Firmino , Gualda Nicolau D. Fares
Published: July 2015

Este trabalho apresenta um modelo analítico para resolver o problema da formação de trens, o qual consiste na definição de seus itinerários, freqüências, tamanhos e perfis de carregamentos e tração, a fim de atender à demanda no período estipulado e sujeito às restrições físicas e operacionais da empresa ferroviária. A heurística desenvolvida leva em conta aspectos fundamentais, como frota heterogênea e limitada de locomotivas e vagões, variação de bitola na malha e cargas com diferentes prioridades. Inicialmente é obtida uma solução de trens diretos, a qual é em seguida objeto de refinamento, para combinar trens e minimizar a movimentação de vagões vazios. A heurística incorpora um algoritmo de caminho mínimo e uma estratégia baseada no problema da mochila binário (knapsack Problem). O modelo foi aplicado com sucesso para um caso real de formação de trens da FEPASA.

ABSTRACT

This work presents an analytical model to solve the train formation problem, which consists of the definition of itineraries, frequencies, sizes, and profiles of shipments and traction of the trains, in order to meet the demand in the specified period, subject to the physical and operational constraints of the rail company. The heuristic presented takes into account fundamental aspects such as heterogeneous and limited fleets of locomotives and wagons, gauge variation in the rail network, and cargoes with different priorities. A solution related to direct trains formation is obtained at first, which is then submitted to a refinement procedure, to combine trains and minimize the movement of empty wagons. The heuristic incorporates a shortest path algorithm and a strategy based on the Knapsack Problem. The model was successfully applied to a real case with data from FEPASA.
Mobility management – o projeto Momentum
Authors: Câmara Paulo
Published: July 2015

Nesse texto o autor apresenta o projeto MOMENTUM (Mobility Management for the Urban Environment) financiado pela União Européia dentro do Programa de Pesquisa e desenvolvimento IV Framework.
The logic of logistics: theory, algorithms and applications for logistics management
Authors: Cunha Claudio Barbieri da
Published: July 2015

Nesse texto o autor apresenta uma resenha acerca do livro "The logic of logistics: theory, algorithms and applications for logistics management", de autoria de Julien Bramel e David Simchi-Levi, publicado pela Springer-Verlag, em 1997.
Determinação dos custos associados à qualidade dos pavimentos através de técnicas de preferência declarada
Authors: Jorge Roberlaine Ribeiro , Cybis Helena Beatriz Bettella , Senna Luiz Afonso Dos Santos
Published: July 2015

O objetivo deste artigo é identificar e quantificar o custo associado à qualidade da pavimentação no meio interurbano. O pressuposto é que a qualidade do pavimento exerce influência na definição dos padrões de viagem e, por conseguinte, deve ser integrada aos demais atributos da função de custo nos modelos de alocação de tráfego. Este trabalho apresenta uma metodologia com vistas a introduzir a influência deste parâmetro na modelagem da alocação de tráfego. Entre as principais conclusões extraídas dos experimentos realizados, destacam-se a comprovação da importância da qualidade da pavimentação no processo de escolha de rotas.

ABSTRACT

The aim of this paper is to identify the costs associated to the quality of road pavements in interurban areas. The main assumption in this work is that pavement quality may be an important issue in the definition of travel patterns and therefore should be in costs functions of traffic assignment models. This work presents the methodology devised to include the effect of the pavement quality on traffic assignment models. The analysis of exploratory tests suggest that the quality of road pavements can play an important role in the route choice process.
A apresentação de informações sobre o tráfego e a utilização de painéis de mensagem variável
Authors: Mont´Alvão Claudia , Braga Marilita Gnecco de Camargo
Published: July 2015

O presente artigo objetiva discutir alguns aspectos relacionados com a apresentação de informação sobre o tráfego, com a utilização de dispositivos utilizados pelas tecnologias de Sistemas Inteligentes de Transporte, como os painéis de mensagem variável. O foco da discussão está centrado nos aspectos de segurança do motorista durante a tarefa de dirigir. A utilização de disciplinas afins, como a Ergonomia, e as pesquisas realizadas nesta área são de grande valia, uma vez que nestas são discutidas as relações entre a informação necessária ao motorista e sua forma de apresentação, quando da sua utilização em sistemas como os painéis de mensagem. Finalmente, apontam-se áreas onde a pesquisa sobre os painéis pode ser continuada, uma vez que a qualidade da informação apresentada pode influir na tomada de informação por parte do usuário.
Viação ilimitada. Ônibus das cidades brasileiras
Authors: Brasileiro Anísio , Henry & Turma Etienne
Published: July 2015

No texto os autores apresentam um resumo do livro “Viação ilimitada. Ônibus das cidades brasileiras”, publicado pela Editora Cultura, em 1999.
Low Temperature, Digital Control, Fast Synthesis of 2-D BNNSs and Their Application for Deep UV Detectors
Authors: Aldalbahi Ali , Yang Renyauan , Li Eric Yiming , Sajjad Muhammad , Chen Yihau , Feng Peter
Published: July 2015

This paper reports low temperature, digital control, fast synthesis of high-quality boron nitride nanosheets (BNNSs) and their electronic device application. Raman scattering spectroscopy, X-ray diffraction (XRD), Transmission electron microscopy (TEM) are used to characterize the BNNSs. With the synthesized various BNNSs, two prototypic types of deep UV photodetectors have been fabricated, and sensitivity, response and recovery times, as well as repeatability have been characterized. Effects of period and thickness of BNNSs on the properties of prototypic photodetectors are also discussed.
Typology of historical discourse
Authors: Minyar-Beloroucheva A.P.
Published: July 2015

The article deals with the typology of historical discourse, which has been on the periphery of discourse analysis. The investigation has shown that historical discourse is typologically heterogeneous, multidimensional and variable.
Intertextual expression of author’s image of “Diariush” by Afanasy Brestsky
Authors: Silina L.A.
Published: July 2015

The article reviews forms of expression of author’s consciousness through analysis of intertextual means of expressing author’s image, and also gives an idea of the world outlook and the role of Afanasy Brestsky in the context of his time.
Keywords: author’s image, narration, publicism
The review of «The life of revend Evfrosinia Polotskaya» on the basis of the Volokolamsk Collection №632
Authors: Slutsky G.
Published: July 2015

«The life of revend Evfrosinia Polotskaya» taken from the handwritten collection №632 was investigated using the XVI version of the book, first published in 1862 in “Memorials of ancient Russian literature”, the publisher is G.A. Kushelev-Bezborodko”. But in this redaction the book isn’t published completely, a lot of distortions were made, moreover, it’s mentioned, that publication of the book was made on the basis of the list of XVI century of Troyatskaya lavra. Studying manuscript in details gives an idea that it belongs to Iosifo-Volotsky monastery collection №632. The article gives textual analysis of manuscript.
Arctic snow distribution patterns at the watershed scale
Authors: Homan Joel W. , Kane Douglas L.
Published: July 2015

Watershed-scale hydrologic models require good estimates of spatially distributed snow water equivalent (SWE) at winter's end. Snow on the ground in arctic environments is susceptible to significant wind redistribution, which results in heterogeneous snowpacks. The scarcity and quality of data collected by snow gauges provides a poor indicator of actual snowpack distribution. Snow distribution patterns are similar from year to year because they are largely controlled by the interaction of topography, vegetation, and consistent weather patterns. Consequently, shallow and deep areas of snow tend to be spatially predetermined, resulting in depth (or SWE) differences that may vary as a whole, but not relative to each other. Our aim was to identify snowpack distribution patterns and establish their stability in time and space at a watershed scale. Snow patterns were established by: (1) using numerous field surveys from end-of-winter field campaigns; and (2) differentiating snowpacks that characterize small-scale anomalies (local scale) from snowpacks that represent a large-scale area (regional scale). We concluded that basic snow survey site descriptions could be used to separate survey locations into regional and local-scale representative sites. Removing local-scale influences provides a more accurate representation of the regional snowpack, which will aid in forecasting snowmelt runoff events.
Linking North Slope of Alaska climate, hydrology, and fish migration
Authors: Betts Erica D. , Kane Douglas L.
Published: July 2015

Arctic grayling (Thymallus arcticus) have a life-history strategy specifically adapted to the extreme climate of the North. These fish migrate to spawning grounds just after breakup in the spring, then migrate to feeding sites in early summer, and finally in the fall migrate back to their overwintering sites. The Kuparuk River is a perennial stream originating in the northern foothills of the Brooks Range on the North Slope of Alaska. Sections of the Kuparuk are periodically intermittent in that, during low flows in the system, these channel reaches appear dry. The flow varies between surface and subsurface in this permafrost-dominated environment, with subsurface flow being limited to the unfrozen thaw bulb around the stream. These dry reaches create a barrier to fish migration due to the lack of surface channel flow. The impacts of a warming Arctic may have implications for the partitioning of flow within the Kuparuk and consequently affect the ability of fish to move within the system at critical times. The timing and duration of these barriers are sporadic, occurring with almost equal probability throughout the summer, with fall dry spells creating the biggest impact on Arctic grayling fitness.
Delineation of potential sites for rainwater harvesting structures using a geographic information system-based decision support system
Authors: Mahmoud Shereif H. , Mohammad F. S. , Alazba A. A.
Published: July 2015

This paper presents a methodology based on a decision support system (DSS) that employs remote sensing and field survey data and geographic information system (GIS) to identify potential rainwater harvesting areas (RWH). This DSS was implemented to obtain suitability maps and to evaluate the existing RWH structures in the study area. The DSS inputs comprised maps of rainfall surplus, slope, potential runoff coefficient, land cover/use, and soil texture. On the basis of an analytical hierarchy process analysis taking into account five layers, the spatial extents of RWH suitability areas were identified by multi-factor evaluation. The spatial distribution of the classes in the suitability map showed that the excellent and good areas are mainly located in the southern and western parts of the study area. On average, 12.2% and 22.2% of the study area are classified as excellent and good for RWH, respectively, while 34.7% and 30.9% of the area are classified as moderately suitable and poorly suited and unsuitable, respectively. Most of the existing RWH structures that are categorized as successful were within the good (72% of the structures) areas followed by moderately suitable (24% of the structures) and excellent areas (4% of the structures).
Modeling of density and calculations of derived volumetric properties for n-hexane, toluene and dichloromethane at pressures 0.1-60 MPa and temperatures 288.15-413.15 K
Authors: Ivanis Gorica , Tasic Aleksandar , Radovic Ivona , Djordjevic Bojan , Serbanovic Slobodan , Kijevcanin Mirjana
Published: July 2015

Densities data of n-hexane, toluene and dichloromethane at temperatures
288.15-413.15 K and at pressures 0.1-60 MPa, determined in our previous work,
were fitted to the modified Tait equation of state. The fitted
temperature-pressure dependent density data were used to calculate the
derived properties: the isothermal compressibility, the isobaric thermal
expansivity, the difference between specific heat capacity at constant
pressure and at constant volume and the internal pressure, over the entire
temperature and pressure intervals specified above. In order to assess the
proposed modeling procedure, a comparison of the obtained values for the
isothermal compressibility and the isobaric thermal expansivity with the
corresponding literature data were performed. The average absolute percentage
deviations for isothermal compressibility were: for n-hexane 2.01-3.64%, for
toluene 0.64-2.48% and for dichloromethane 1.81-3.20%; for the isobaric
thermal expansivity: for n-hexane 1.31-4.17%, for toluene 0.71-2.45% and for
dichloromethane 1.16-1.61%. By comparing the obtained deviations values with
those found in the literature it can be concluded that the presented results
agree good with the literature data.
Closed-Form Representations of the Density Function and Integer Moments of the Sample Correlation Coefficient
Authors: Provost Serge
Published: July 2015

This paper provides a simplified representation of the exact density function of R, the sample correlation coefficient. The odd and even moments of R are also obtained in closed forms. Being expressed in terms of generalized hypergeometric functions, the resulting representations are readily computable. Some numerical examples corroborate the validity of the results derived herein.
Association between the NF-E2 Related Factor 2 Gene Polymorphism and Oxidative Stress, Anti-Oxidative Status, and Newly-Diagnosed Type 2 Diabetes Mellitus in a Chinese Population
Authors: Wang Xia , Chen Hongxia , Liu Jun , Ouyang Yingying , Wang Di , Bao Wei , Liu Liegang
Published: July 2015

Oxidative stress is a major risk factor in the onset and progression of type 2 diabetes mellitus (T2DM). NF-E2 related factor 2 (NRF2) is a pivotal transcription factor in oxidative stress related illnesses. This study included 2174 subjects with 879 cases of newly-diagnosed T2DM and 1295 healthy controls. Compared to individuals with the CC genotype, those with the AA genotype had lower total anti-oxidative capacity, superoxide dismutase, catalase, glutathione, glutathione peroxidase activity; and lower homeostasis model assessment of β-cell function index. Those with the AA genotype also had a higher malondialdehyde concentration and homeostasis model assessment of insulin resistance index values. The frequency of allele A was significantly higher in T2DM subjects (29.4%), compared to control subjects (26.1%; p = 0.019). Individuals with the AA genotype had a significantly higher risk of developing T2DM (OR 1.56; 95% CI 1.11, 2.20; p = 0.011), relative to those with the CC genotype, even after adjusting for known T2DM risk factors. Our results suggest that the NRF2 rs6721961 polymorphism was significantly associated with oxidative stress, anti-oxidative status, and risk of newly-diagnosed T2DM. This polymorphism may also contribute to impaired insulin secretory capacity and increased insulin resistance in a Chinese population.
New Fluorescence Probes for Biomolecules
Authors: Jurek Katarzyna , Kabatc Janina , Kostrzewska Katarzyna , Grabowska Marlena
Published: July 2015

Steady state fluorescence measurements have been used for the investigation of interaction between the bovine serum albumin (BSA) and fluorescence probes: 3-hydroxy-2,4- bis[(3-methyl-1,3-benzoxazol-2(3H)-ylidene)methyl]cyclobut-2-en-1-one (SQ6), 3-hydroxy- 2,4-bis[(3-methyl-1,3-benzothiazol-2(3H)-ylidene)methyl]cyclobut-2-en-1-one (SQ7) and 3-hydroxy-2,4-bis[(1,3,3-trimethyl-1,3-dihydro-2H-indol-2-ylidene)methyl]cyclobut-2-en-1-one (SQ8). The binding constant between bovine serum albumin and squarine dyes has been determined by using both the Benesi-Hildebrand and Stern-Volmer equations. The negative value of free energy change indicates the existence of a spontaneous complexation process of BSA with squarine dyes.
Potentiometric NO2 Sensors Based on Thin Stabilized Zirconia Electrolytes and Asymmetric (La0.8Sr0.2)0.95MnO3 Electrodes
Authors: Zou Jie , Zheng Yangong , Li Junliang , Zhan Zhongliang , Jian Jiawen
Published: July 2015

Here we report on a new architecture for potentiometric NO2 sensors that features thin 8YSZ electrolytes sandwiched between two porous (La0.8Sr0.2)0.95MnO3 (LSM95) layers—one thick and the other thin—fabricated by the tape casting and co-firing techniques. Measurements of their sensing characteristics show that reducing the porosity of the supporting LSM95 reference electrodes can increase the response voltages. In the meanwhile, thin LSM95 layers perform better than Pt as the sensing electrode since the former can provide higher response voltages and better linear relationship between the sensitivities and the NO2 concentrations over 40–1000 ppm. The best linear coefficient can be as high as 0.99 with a sensitivity value of 52 mV/decade as obtained at 500 °C. Analysis of the sensing mechanism suggests that the gas phase reactions within the porous LSM95 layers are critically important in determining the response voltages.
Reciprocals and Cumulation
Authors: Beck Sigrid
Published: July 2015

No abstract.
Study on LNG Carrier Safety and Explosive Boiling Effects on the Process of LNG Releasing on Water
Authors: Zhang Bin , Yu Gui Feng , Feng Xing , He Ling , Zhang Jian Wei
Published: July 2015

LNG carrier is seen as high risk and high economy ship. So this paper is concern about strengthening LNG carriers’ safety servicing on board, evaluated risks during this process and finding out and analyzing the risks occurring mechanisms in detail. Furthermore, the LNG releasing process is simulated by numerical models, which provides a numerical method to evaluate LNG releasing consequence. By analyzing explosive boiling occurring mechanism, the decision conditions have been included in this simulation process. By comparing the results, the effects of explosive boiling have been concluded.
Rapid Synthesis and Characterization of CuInS2 Prepared Using Microwave-Assisted Heating
Authors: Tsai Ming Kwen , Lee Yueh Chien , Huang Chia Chih , Hu Sheng Yao , Tiong Kwong Kau , Chen Bo Jhin
Published: July 2015

In this work, the CuInS2 nanoparticles are successfully synthesized by microwave-assisted heating technique and further calcined at 400 °C. The morphological, structural, and optical properties of the synthesized CuInS2 nanoparticles are investigated by scanning electron microscope (SEM), X-ray diffraction (XRD), Raman scattering, and transmittance measurement, respectively. The SEM image shows the clear particle shape of the calcined CuInS2 nanoparticles. After calcination treatment, the fundamental (112) peak of the XRD spectrum and a broad Raman peak mixed with chalcopyrite and CuAu structures support the improved crystallinity of the calcined CuInS2 nanoparticles.
High-Temperature Oxidation of Ti3Al0.7Si0.3C2 Carbide at 1100 and 1200°C in Air
Authors: Lee Dong Bok
Published: July 2015

The oxidation of Ti3Al0.7Si0.3C2 carbide at 1100 and 1200°C in air for up to 50 h resulted in the formation of rutile-TiO2, α-Al2O3 and SiO2. Depending on the location of the carbide, either thin, dense, single layered oxide scales or thick, porous, bi-layered oxide scales formed. The single layered scales consisted primarily of protective Al2O3. The bi-layered scale consisted primarily of an outer (TiO2+Al2O3)-mixed oxides, and an inner TiO2-rich, (Al2O3+SiO2)-containing oxides. Since the testing temperatures were high, the oxidation rates varied much depending on the location of the carbide.
The Single-Abrasive Coupled Flutter Model in Power Ultrasonic Honing
Authors: Zhang Xiao Qiang , Zhu Xi Jing , Geng Hai Zhen , Wang Jian Qing , Cheng Quan , Cheng Ling Long
Published: July 2015

Flutter, a dynamic and severe self-excited vibration, easily produced in power ultrasonic honing, is one of the important factors, which affects the processing quality of the workpiece, the efficiency of the machine tool. Based on the study of power ultrasonic honing mechanism, choosing single abrasive and workpiece as research objects, respectively establishe the physical and mathematical coupled flutter model of power ultrasonic honing nonlinear system, with two degrees of freedom, determine the differential expression of the model, and simulate the boundry of flutter condition. It is proved flutter is produced in ultrasonic vibration honing, then the way is proposed to restrain. The study provide a theoretical basis for deeply seeking the strategy to repress and eliminate the flutter.
Development of a Simulation Model of Cutting Slabs in a Continuous Casting Machine
Authors: Aksyonov Konstantin , Antonova Anna
Published: July 2015

In the article the development of a simulation model of cutting slabs in a continuous casting machine is considered. Simulation modeling is used to optimize the sequence of the melts supplied to the continuous casting machine. The goal of optimization is to reduce the deviation between the estimated and actual numbers of slabs, because such deviations can lead to missed deadlines. The model of cutting slabs has been designed with the use of a models creation module of the metallurgical enterprise information system. The models creation module supports the simulation model creation and multi agent simulation. Agents in the developed model are intended to describe the cutting slabs algorithm used by technologists in the metallurgical production. As a result of experiments with the model the following solution has been found. The following sequence of melts should be supplied to the continuous casting machine: initially the melts from the usual quality steel, followed the melts from the high quality steel.
Current Status and Problems of Building Interior Decoration Using Low Formaldehyde-Emitting Materials in Taiwan
Authors: Huang Lin Lin , Juan Han Cheng
Published: July 2015

Regardless of material regulations at the supply source or post-construction quality inspection systems, certain levels of model management systems have been developed. However, in the hospital waiting room, the measured formaldehyde concentration in the air reached 0.99 ppm, which is 12 times higher than that of the standard value.
The formaldehyde emission rates measured in the building materials of the private housings or hospital waiting room ranged from 158 to 238 μg/m2∙h, which exceed both the ABSL and BSMI standards. Moreover, the decoration locations, construction staff, and construction behaviors varied despite their claims of using low formaldehyde-emitting materials.
This study compiled the current objectives and regulations established by various supervising authorities and implemented a supporting management system in material grading, amount of material usage, ventilation path control, and ventilation effectiveness for facilitating the promotion of healthy indoor air quality, thereby enhancing public health.
Material Damping of Crushed Rock in Free-Decay Mode
Authors: Senetakis Kostas , Anastasiadis Anastasios
Published: July 2015

Damping of geo-materials in resonant column test is commonly evaluated with two alternative experimental methods; during a steady-state vibration (SSV) and during free-vibration decay (FVD). Damping is an important dynamic property necessary to capture the complete behavior of soils. In the study, representative test results on crushed rock are discussed with a focus on material damping derivations along with stiffness degradation test results derived from torsional resonant column tests. A comparison between material damping derived from the SSV and FVD methods and from small to medium shear strains is presented and discussed. In the first part of the paper, the definition of material damping by means of a closed loop in the shear stress - shear strain plane is presented along with a report on literature data associated with damping of coarse-grained soils and the important factors that control material damping of sands and gravels. In the second part, the materials and experimental techniques of the study are described briefly and the background of determining material damping in a resonant column test is also presented along with the analytical formulae. Finally, in the third part representative test results are given including both stiffness and damping, and a comparison of damping derivations using different methods is also highlighted.
Catastrophic Results for Equipment and Machine Driving Systems when High Impact during Operation Occurs
Authors: Aparecido Martins Jairo , Pardal Paula Cristiane Pinto Mesquita , Romão Estaner Claro
Published: July 2015

Energy is vital to machines and equipment basic functioning. On the other hand, it has an ambiguity determined by its detrimental side under other circumstances. This paper aims to present a review of simple laws of physics / mechanics in order to understand some benefits of using such energies (kinetic and potential energies), in order to process products or generating movement (mechanical energy). However, also shows its damaging side for driving systems, where such energies may generate catastrophes, usually due to high impacts. This last, which destroys complete or partial systems due to the absence of any robust / preventive protection. There is a safety manner (solution) to protect the systems, described along the text.
A Gear Micropump without Bearings Production
Authors: Rodionov Leonid , Rekadze Pavel , Stryczek Jarosław
Published: July 2015

Progress in the field of microelectronics and micromechanics has created new opportunities for the development of fluid power microsystems and microhydraulics. Miniaturization of hydraulic elements allows replacing the classical hydraulics with microhydraulics, where due to size or weight the former cannot be applied. Gear pumps are common use due to their reliability, resistance to working medium impurities, high efficiency, small size in comparison with other pumps and simple and compact design. Therefore micropumps often associate with a gear pump type. A micropump entails microbearings production. This requirement leads to cost increasing due to requirements to high accuracy of manufacturing. The paper focuses on a method for micropumps production without bearings. The idea based on application of materials with satisfactory friction coefficient in pairs. Friction pairs analysis made from different polymer and composite materials was carried out. As a result a gear micropump was designed and produced.
A Harmonic Source Location Method Based on PMU Measurements in Distribution Network
Authors: Li Bing Jun , Zhou Su Quan , Lun Xiao Xiang
Published: July 2015

It is of great importance to identify the location of the harmonic sources for the harmonic governance in the power system. Applied with optimal measurement placement (OMP) and harmonic state estimation (HSE), this paper presents a novel process based on PMU measurements to locate the harmonic sources in the distribution network. Considering the cost and the observability, the OMP can provide a scheme of the measurement placement with the minimum number of PMU measurements. In order to simplify the HSE equation, the measured data are converted to the form of voltage by the method proposed in this paper.By solving the HSE equation, the location and magnitude of the harmonic source are evaluated. The methodology is applied to the IEEE 33-bus system, and the obtained results are properly analyzed.
Focus on Carbide-Tipped Circular Saws when Cutting Stainless Steel and Special Alloys
Authors: Rosso Mario , Peter Ildiko , Gobber Federico
Published: July 2015

Circular saw blades are used exclusively for cut-off work, ranging from small manual feed operations, up to very large power fed saws commonly used for sectioning stock as it comes from a rolling mill or other manufacturing processes for long products. The teeth profile, as well as the tooth configuration are of fundamental importance for the blade performances; through a combination of blade rigidity and grinding wheel condition a good quality surface finish is attained for tools of commercial standard. The materials used for the production of circular saw blades are ranging from high speed steel to cemented carbides. In particular, cemented carbides, being characterized by high hardness and strength, are used in applications where materials with high wear resistance and toughness are required. The main constituents of cemented carbides are tungsten carbide and cobalt. Tungsten carbide imparts the alloys the necessary strength and wear resistance, whereas cobalt contributes to the toughness and ductility of the alloys. The WC-Co alloys are tailored for specific applications by the proper choice of tungsten carbide grain size and the cobalt content. The grain size of the tungsten carbide in WC-Co varies from about 40 µm to around 0.3 µm, the cobalt content from 3 to 30 wt%. The coarse grained hardmetals are mainly used in mining applications, the smallest grain size being about 3 µm and the minimum cobalt content 6 wt%. The grain size of tungsten carbide in the metal cutting industry, as well as for universal applications lies in the range of 1-2 µm. However, with the advent of near net shape manufacturing and thin walled components, the use of submicron carbide is growing, since their high compressive strength and abrasive wear resistance can be used to produce tools with a sharp cutting edge and a large positive rake angle.In this invited paper, a general overview on the actual trends in the choice of the best material when cutting special alloys will be presented and discussed. Based on the recent and past literature some examples of their up-to-date application, such as circular saws used to cut stainless steels and some high strength alloys, are talk over.
The Effect of Ce Added to Carburizing Paste on Phase Composition of Carburized Surface Layers
Authors: Cojocaru Mihai , Dragomir Daniela , Druga Leontin , Kuncser Victor , Badica Petre
Published: July 2015

Investigations on carburized layers phase composition are usually made ​​by optical microscopy, electron microscopy and X-ray diffraction. A microstructure consisting in different proportions of superior bainite, inferior bainite, martensite and retained austenite was found after carburizing in paste of the 21NiCrMo2 steel which has appropriate bainitic hardenability. The investigations carried out on 21NiCrMo2 steel samples, carburized in paste with additions of about 10% Ce, highlighted a significant change of phase proportions ratio in the carburized layer resulting in an important increasing of the lower bainite ratio. It was also observed, that the carburized layer case depth obtained in the carburizing paste with Ce additions does not significantly differ in relation to that attained in the carburizing paste without Ce additions but the microhardness increases considerably. The reason is connected also to the presence of Ce carbide identified by X-ray diffraction in the carburized layer. The Ce hard affinity towards oxygen and its influence on bainitic hardenability increasing is well known and adopted, however neither Ce transfer mechanism from carburizing paste to the carburizing layer and nor the effects of its high affinity to oxygen (for example) are not addressed in this particular case. The present study proposes a possible transfer mechanism of Ce in the carburized layer and an explanation of the consequences of Ce hard affinity towards oxygen on the phase composition of the carburized layer. Nanoscale iron oxides such as wüstite, magnetite and maghemite were identified in the surface of the carburized layer by Mössbauer spectrometry.
In Vitro Corrosion Behaviour of Metallic Dental Materials
Authors: Vrânceanu Diana Maria , Tarcolea Mihai , Gherghilescu Ana Iulia , Miculescu Florin , Cotrut Mihai Cosmin
Published: July 2015

Typical applications of metallic dental materials include metal-ceramic restorations, dental implants or orthodontic systems. Due to their contact with human tissues, corrosion resistance is one of the main requirements for dental materials. In the present paper, the corrosion behaviour in Fusayama Meyer artificial saliva solution (pH=5.2) on a selection of four different metallic dental materials (316 L steel, Au based alloy, cp-Ti, Ti6Al4V alloy) currently used in dentistry were investigated. The metallic dental materials have been investigated in terms of electrochemical analysis, chemical composition, morphology before and after corrosion, wettability and roughness. The results showed a hydrophilic behaviour in the case of Au based alloy, cp-Ti and Ti6Al4V alloy, and hydrophobic for 316L stainless steel. Considering the main electrochemical parameters, the cp-Ti alloy exhibited better corrosion resistance in artificial saliva with pH=5.2, followed by Au based alloy, Ti6Al4V alloy and 316L stainless steel. The main objective of the present paper was to evaluate the corrosion behaviour, as in important factor in the selection of metallic materials used in dentistry.
Thermal Analysis of Heat Sinks for a Power Thyristor Module
Authors: Fărcaş Cristian , Fodor Alexandra , Pitică Dan
Published: July 2015

The paper presents a study about thermal behavior of heat sink - power thyristor assembly. The models of power thyristor and the model of heat sink were modeled in SolidWorks. These models have been used in simulations. We take into consideration different conductor materials for heat sinks and different thermally conductive pastes. A thermal analysis has been performed for different places of power module on heat sink. In our study, we have taken into consideration the influence of the different materials of heat sink in heat dissipations. The results of performed simulations realized with Solid Works are presented in the paper.
Studies on Fe-Cr-Ni-Si-B Bulk Metallic Glass for Automotive Applications
Authors: Lucaci Mariana , Patroi Delia , Tsakiris Violeta , Lungu Magdalena Valentina , Manta Eugen , Iorga Alexandru
Published: July 2015

Researches and developments were carried out for obtaining of bulk metallic glass (BMG) from the Fe-Cr-Ni-Si-B system. The used processing methods were copper mold casting and melt spinning method. The resulted materials are in form of sheets with sizes of 69.7 x 64 x 3/1.5 mm and of strips with thickness less than 50 microns, which were obtained by varying the melt spin technological parameters. The both processing variants are not suitable for obtaining such of alloy in bulk metallic glass form. Adding of zirconium to this alloy produces bulk metallic glasses only for the melt spin products. The DSC analysis emphases that the zirconium modified alloy processed by melt spinning method exhibits a high glass forming ability (GFA).
Physical and Mechanical Properties of Concrete Incorporating Manufactured Sand
Authors: Ali Maisarah , Nordin Muhammad Hariz , Saad Siti Asmahani
Published: July 2015

Concrete is a common material that widely used in construction industry. Excessive usage of this material causes exhaustibility to its components, especially fine aggregate or sand. In this regard, the use of manufactured sand is considered as a part of the solutions to fix this problem as it is readily available. In this research, the manufactured sand is used at 40%, 50% and 60% to replace natural river sand. SEM analysis reveals the rough surface texture of manufactured sand. The manufactured sand has angular shape and sieve analysis reveled that it has a considerable amount of fine particle. Slump test shows that concrete using manufactured sand pass the standard. On the other hand, compressive test shows that concrete cubes using manufactured sand do not achieved the target strength. Water absorptive test on the cubes revealed that M-Sand I has higher absorptivity property compared to river sand . SEM analysis revealed the existance of microcrack as well as porosity in in concrete cubes incorporating of manufactured sand. It can be concluded that it can be concluded that the higher the percentage of manufactured sand in the concrete mix the lower is the comprensive strength.
Cost Analysis of Using Hybrid Microwave Post-Sintered Silicon Nitride Inserts
Authors: Ariff Tasnim Firdaus , Iqbal Mohammad , Bahar Rubina
Published: July 2015

Heat treatment is a process often used to improve product performance by increasing the strength of material or other desirable characteristics. Silicon nitride (Si3N4) tool insert is known for its attractive properties including high fracture toughness, strength and wear resistance at elevated temperatures. Heat treating these inserts by post-sintering them for 15 minutes at 600°C using conventional heating and hybrid microwave energy has prolonged tool life by 11-21% and 48-94% respectively. Machining was performed on a T6061 Aluminium alloy rod for tool life analysis at three different cutting speeds; 215, 314 and 393 m/min. Cost analysis is performed on these post-sintered Si3N4 inserts and found that there are economical benefits in the tooling cost when compared with the untreated Si3N4 inserts.
Effect of Nanofiller on Flexing Mechanism of HDPE/EPR Nanocomposite for Sport Shoe Sole Application
Authors: Lutpi Husniyah Aliyah , Anuar Hazleen , Shaffiar N.M.
Published: July 2015

For this decade, nanocomposite has received huge interest from over a thousand of researchers due to its outstanding properties in wide applications. Nanocomposite of sole shoes has become new development in sport shoes application while no interest from others has been reported. The purpose of this study is mainly to produce prototype and characterize flexing mechanism of nanocomposite outsole. The materials used for the outsole protoype were polymer matrix of high density polyethylene (HDPE) and ethylene propylene rubber (EPR) at ratio of 70:30 by wt% was added by 3 wt% of CNT nanofiller. The HDPE/EPR-CNT nanocomposites were prepared via single melt blending by using internal mixer and then compression moulded into outsole shape. The outsole was then gone through electron beam (EB) radiation at 100 kGy/s. The flexibility of unradiated and radiated nanocomposite outsole were tested by flexing test according to SATRA TM161 and ISO-17707 standard and fractography of the nanocomposite outsole was observed visually. EB radiated nanocomposite show high properties which suggesting that greater count number in flexing test and less void was observed compared to the unradiated nanocomposite.
Mechanical and Physical Properties of Sago Starch/Halloysite Nanocomposite Film
Authors: Ahmad Zuraida , Hermain Hazwan Yatimi , Abdul Razak Nur Humairah
Published: July 2015

The incorporation of unmodified halloysite nanotube (HNT) in a thermoplastic sago starch (TPSS) film to form a nanocomposite material was investigated. The TPSS/HNT nanocomposite was fabricated through solvent casting method at varying HNT loading of 0, 0.25, 0.5, 1.0, 3.0, and 5.0 wt.%. Evaluation on mechanical and physical properties (tensile test, water absorption, thickness and density) was made to study the effect of HNT loading on the TPSS properties. Tensile strength achieved an optimum value at 0.25 wt.% of HNT loading and decreased with higher addition of HNT. Meanwhile higher amount of HNT in the nanocomposite film exhibited brittleness with the reduced tensile strain. Water absorption decreased with the addition of HNT due to the difficulty of water molecules to pass through the tortuous path of HNT structure. Thickness and density of the nanocomposite film, however, increased at higher HNT contents. FESEM (field emission scanning electron microscope) which examined the surface morphology of the TPSS/HNT nanocomposite displayed uniformly dispersed HNT in the plasticized starch matrix.