bluuebunny/crossref_metadata_2025 huggingface dataset:
ANÁLISE DA ATIVIDADE POZOLÂNICA DA CINZA LEVE DO BAGAÇO DE CANA-DE-AÇÚCAR E SUA APLICAÇÃO NA PRODUÇÃO DE PAVERS
Authors: Martins Carlos Humberto , Mazzaro Felipe Oliveira , Martins Filho Sergio Tunis , Cruz Prieto Hojo Liri Yoko
Published: February 2016

A expansão do setor da construção civil implica no aumento do consumo de recursos naturais, com isso as pesquisas tem buscado substituir os insumos da construção civil por resíduos industriais com potencial de reutilização. O Brasil é o maior produtor de açúcar e etanol, e, por este setor ser um potencial gerador de resíduos, este projeto utilizou um dos subprodutos da cana-de-açúcar para o estudo, a cinza leve gerada na queima do bagaço de cana-de-açúcar para co-geração de energia elétrica. Sendo assim, o trabalho tem como objetivo analisar a pozolanicidade da cinza leve do bagaço de cana-de-açúcar para substituir parcialmente o cimento Portland utilizado na produção de blocos de concreto intertravados (pavers). Inicialmente fez-se a análise da cinza leve por meio de caracterização física e química, análise da atividade pozolânica e posteriormente testes de resistência à compressão simples e absorção de água nos pavers produzidos com substituição parcial do cimento pela cinza leve, em porcentagens de 2,5 %, 5 % e 7,5 %. Os resultados comprovaram que a cinza leve do bagaço da cana é um resíduo viável para substituição parcial do aglomerante, pois na sua composição química apresentou-se com o mínimo exigido pela ABNT NBR 12.653 (2001), e, os índices de atividade pozolânica superiores aos mínimos exigidos pela ABNT NBR 15.895 (2010). A substituição parcial do cimento por cinza leve do bagaço da cana na produção dos pavers mostra-se viável em um teor de 5%, possibilitando sua utilização para solicitações leves tais como tráfego para pedestres.
MAPEAMENTO DOS BAIRROS SUSCETÍVEIS À INUNDAÇÕES NO MUNICÍPIO DE JAÚ-SP
Authors: Da Silva Keila Camila , Poleto Cristiano
Published: February 2016

Inundações são fenômenos que ocorrem em diversas regiões do mundo, caracterizadas por situações onde ocorre o transbordamento do rio. Normalmente as maiores proporções ocorrem em áreas urbanas. Usa-se o nome de enchente a situação natural de transbordamento de água do leito do rio, já as inundações estão relacionadas a intensificação desse processo por ações humanas, ocasionando danos, prejuízos e modificações na dinâmica natural. A identificação das áreas de risco de inundações, através do mapeamento é um instrumento para o controle e prevenção desse desastre. Esse trabalho procurou mapear pontos de risco de inundação no município de Jaú, localizado na região central do estado de São Paulo. As inundações no município foram classificadas em graduais e bruscas, sendo a primeira, aquelas que ocorrem em bairros próximos ao rio, com seu transbordamento, e a segunda, ocorrem devido a drenagem inexistente/ineficiente.
MODELO DE ELEMENTO FINITO DE TRELIÇA PLANA CONSIDERANDO A FLAMBAGEM E A NÃO LINEARIDADE FÍSICA
Authors: Souza Luiz Antonio Farani de
Published: February 2016

As treliças possuem um vasto campo de aplicação na Engenharia de Estruturas, sendo muito utilizadas na construção de pontes, em estruturas de cobertura de edificações, em torres de transmissão de energia, entre diversos outros usos. Em geral são relativamente leves e especialmente indicadas para superar grandes vãos ou suportar carregamentos elevados. Nesse contexto, as treliças tornam-se uma solução econômica e prática. Este artigo tem como objetivo avaliar o comportamento estrutural de treliças planas via Método dos Elementos Finitos considerando o comportamento pós - flambagem e a não linearidade física. A relação constitutiva da barra é descrita por um modelo fundamentado na teoria da Mecânica do Dano Contínuo. As trajetórias de equilíbrio são fornecidas por meio de uma análise incremental e iterativa baseada no método de Newton - Raphson. Um código computacional é desenvolvido e implementado com o programa Scilab, e análises numéricas são efetuadas a partir de problemas de treliças encontrados na literatura, discutindo-se alguns aspectos envolvidos na modelagem computacional. Os resultados numéricos preditos pela modelagem proposta demonstram a potencialidade do algoritmo em estimar a capacidade resistente última da estrutura.
MÉTODO AHP APLICADO AO PROBLEMA DE LOCALIZAÇÃO DE UMA CENTRAL DE ASSISTÊNCIA PARA SITUAÇÕES EMERGENCIAIS NO ESTADO DO PARANÁ
Authors: Drozino Beatriz , Oliveira Fernanda Bianchini Rodrigues , Samed Márcia Marcondes Altimari
Published: February 2016

Os problemas de localização no âmbito da logística humanitária estão inseridos em um cenário caracterizado como caótico, e de elevada imprevisibilidade, em que as decisões precisam ser dinâmicas e em tempo real, a fim de salvar vidas e minimizar os impactos para a sociedade. Neste contexto, a contribuição deste trabalho é apresentar uma estratégia para o planejamento da localização do centro temporário de apoio a situações de catástrofes naturais, como inundações e deslizamentos de terra, usando dados do estado brasileiro do Paraná. Para tanto, utilizou-se o método Analytic Hierarchy Process (AHP), tal que a localização do centro de ajuda para resposta a catástrofes naturais foi baseada na análise de critérios e subcritério, bem como análise e classificação das alternativas. Com base nos resultados obtidos, conclui-se que a utilização desta abordagem na fase de preparação para o desastre pode melhorar o nível de eficiência no processo de tomada de decisões e otimizar as operações em fase de resposta.
EFEITOS DAS CONDIÇÕES REACIONAIS DE TRANSESTERIFICAÇÃO ALCALINA A PARTIR DE ÓLEOS RESIDUAIS
Authors: Oliveira Carlos de Jesus de , Miyashiro Carolina Sayury , Teleken Joel Gustavo , Meier Thompson Ricardo Weiser , Parisotto Emanuelle Iaçana Berté , Cremonez Paulo André
Published: February 2016

A produção de biodiesel tem um elevado custo devido ao alto preço da principal matéria-prima utilizada (óleo de soja) na síntese. Dessa maneira, tornam-se viáveis a utilização de matérias-primas não comestíveis, como os óleos residuais de frituras. O presente trabalho teve como objetivo realizar um planejamento fatorial no processo de produção de biodiesel a partir de óleos residuais para estudar a influência das variáveis: temperatura, massa de catalisador e razão molar álcool/óleo. Para isso, levou-se em consideração a conversão dos triglicerídeos em ésteres metílicos de acordo com os substratos gerados, bem como a concentração do produto final visando a otimização da síntese experimental. Notou-se que dentre os parâmetros estudados, que a massa do catalisador teve a maior interferência significativa, considerando-se o volume final da mistura de ésteres produzida, seguida das variáveis razão molar (álcool / óleo) e temperatura.
Distribution Status of Trace Oxygen in Fe3Si-Si3N4
Authors: Gao Mei , Li Yong , Qin Hai Xia , Li Bin , Sun Jia Lin , Chen Jun Hong , Xue Wen Dong
Published: February 2016

The distribution status of trace oxygen in the ferro-silicon nitride (Fe3Si-Si3N4) was investigated at the present, which was prepared by flash combustion synthesis method from FeSi75. The results showed that while the grain size of FeSi75 used in preparing Fe3Si-Si3N4 was less than0.074 mm, “active oxidation” occurred firstly, silicon was oxidized to form gaseous SiO(g), oxygen partial pressure was reduced in the system, silicon reacted with nitrogen directly to form Si3N4 while the system oxygen partial pressure approached less than 10-19MPa (T=1823K). O2(g) promoted the formation of Si3N4, Gaseous SiO(g) finally reacted with nitrogen and Si to form Si2N2O. The ferro silicon nitride was characterized by X-ray diffractometer and scanning electron microscope, the distribution of Si2N2O was uneven in the silicon nitride, and Si2N2O mainly distributed around Fe3Si or near the hole.
Effects of Withdrawal Speeds on Properties of ZnO Thin Films Prepared by Sol-Gel Immerse Technique
Authors: Du Chao , Zou Yu Chun , Chen Zhi Qing , Li Wen Kui , Luo Shan Shan
Published: February 2016

ZnO thin films have attractive applications in photoelectric device, due to their excellent chemical, electrical and optical properties. In this paper, ZnO thin films with good c-axis preferred orientation and high transmittance are prepared on glass sheets by sol-gel immerse technique. The effects of withdrawal speeds on the growth process of thin film crystal, film crystal orientation and the crystallinity, the optical performance were investigated by XRD, SEM and UV-Vis spectrophotometry. The results show that the thin films were composed of better hexagonal wurtzite crystals with the c-axis prepared orientation. The transmittance of prepared thin films is over 80% in the visible-near IR region from 600 nm - 800 nm. ZnO films have sharp and narrow diffraction peaks, which indicates that the materials exhibit high crystallinity. With the withdrawal speeds increasing, the grain size of ZnO thin films and the intensity for all diffraction peaks were increased gradually. The growth model is changed from the stratified structure into the island structure in the growth process. The transmittance of the thin films decrease in the visible wavelength region, with the withdrawal speeds increasing.
Machinability and Material Removal Mechanism of Face Centred Cubic (FCC) Conductive Ceramic TiBCN in EDM Processing
Authors: Zhao Jian Chuang , Hu Jian Dong , Meng Fan You , Wang Yao Min
Published: February 2016

Fcc-TiBCN powder synthesized by boronizing of Ti was pressured into monolithic block by hot pressing (HP) method. Then the block material was machined by wire-cut EDM. The machinability and the material removal mechanisms were discussed of Fcc-TiBCN block in wire-cut EDM. Results show that the machinability of Fcc-TiBCN is satisfying. The discharge current has little relationship on surface roughness in the range of factory-adjusted optimum settings. The discharge duration and pulse interval time play an important role on the quality of machined surface and EDM machining efficiency. In order to obtain excellent quality of the machined surface, the number of power tube turned on can not exceed 6, and the pulse interval time must be as long as possible. The mini roughness of machined surface is 0.4μm～0.6μm as the number of power tube turned on is 5, the pulse interval time and discharge duration is set in the range of 20～22μs and 65～75μm, respectively. There are three material removal mechanisms of TiBCN conductive ceramic in the EDM machining process: spalling, melting and evaporation. Spalling is the main mechanism resulted by thermal stress superposing.
Reaction Fusion and Spatial Span-Scale Microstructure Evolution of TiB2-Based Ceramic and Metal Achieved by High Gravity Field
Authors: Song Ya Lin , Zhang Long , Zhao Zhong Min , Song Yi Gang
Published: February 2016

The plates of 1Cr18Ni9Ti stainless steel were selected as metal substrates, and CrO3+Al thermites were introduced into B4C+Ti primary system for enhancing adiabatic temperature of reaction system. By improved processing route, i.e. respectively preparing, ball-milling and compacting B4C+Ti blends and CrO3+Al thermites and subsequently filling them one by one into the crucibles, TiB2ceramic to 1Cr18Ni9Ti graded composites were prepared by reaction joining in high-gravity field. it was found that refined TiB2 platelets were embedded in or around the irregular TiC grains, and Fe-Cr-Ni metallic phases were distributed between TiC and TiB2 phases, and Al2O3 inclusions disappeared completely at the intermediate between TiB2ceramic and 1Cr18Ni9Ti, the thickness of which reached 1.05 mm. The 3D net ceramic-metal composite microstructure (3DNCMCM) existed at the intermediate. The Vickers hardness distribution of the intermediate appeared the parabolic gradient composite feature, and the shear strength of the intermediate reached 325±15 MPa because of the increasing thickness of intermediate, at which 3D net ceramic-metal composite microstructure (3DNCMCM) existed.
High Temperature Bonding Effect of the Room-Temperature-Curing Phosphate Adhesive for C/C Composites
Authors: Wang Ming Chao , Zhuang Meng Meng , Tao Xin , Xu Xi Qing , Geng Hai Tao , Liu Jia Chen
Published: February 2016

A heat-resistant phosphate adhesive was developed for joining and repairing of C/C composites. The high-temperature bonding effect for both cured adhesive and 1300°C-calcined adhesive had been evaluated through testing high-temperature shear strength of corresponding joints. The results showed that the bonding strength of cured adhesive decreased from 7.9 MPa at RT to 0.9 MPa at 1300°C, while that of 1300°C-calcined adhesive could maintain about 4 MPa at temperature range from RT to 700°C and then decreased to 1.7 MPa at 1300°C. Besides, with the increasing thermal cycling times at 1300°C, the high-temperature bonding strength at this temperature could maintain at about 2.3 MPa.
The Morphologies and Photoluminescence of Ce3+-Doped 0.5La2O3-2SrO-0.5Al2O3 Phosphors with SrF2
Authors: Gu Xi Guang , Fu Ren Li , Tang Ye , Yang Fang
Published: February 2016

Ce3+-doped 0.5La2O3-2SrO-0.5Al2O3 (LSA:Ce) phosphors had been successfully synthesized using a conventional solid-state reaction method under reducing atmosphere (H2/N2 =1/5). The phase, morphologies and luminescence properties of the LSA:Ce phosphors were investigated. The emission intensity of LSA:Ce phosphors was improved by the addition of SrF2 as flux, and red shift of PL spectra peak was observed in this phosphors. Research results shown that the LSA:Ce phosphors have the potential to meet the development of white light-emitting diodes.
Microstructure and Corrosion Behaviour of Laser-Clad Double-Ceramic-Layer Composite Coating
Authors: Wu Qian Lin , Li Wen Ge , Dong Li Hua , Yin Yan Sheng
Published: February 2016

A double-layer composite coating on Q235 steel substrate was prepared using a new developed in situ technology consisting of SHS reaction, laser cladding and metal dusting techniques. A double-layer composite coating consists of the TiO2–TiC ceramic outer layer and the TiC-CNTs cermet inner layer. An excellent bonding was observed among the outer layer, the inner layer and the steel substrate. Corrosion behavior of the coating was investigated and the commercial 304SS was used for comparison. The outer layer exhibited the highest corrosion resistance and 304SS the lowest corrosion resistance, whereas the inner coating exhibited the intermediate corrosion resistance. However, the severe pitting corrosion which was observed in 304SS did not exist for the coating.
The Solution Dependence of Cu Modification During the Synthesis of γ-Fe2O3 Nanoparticles
Authors: Lin Yue Qiang , Mao Hong , Li Jian
Published: February 2016

During the synthesis of γ-Fe2O3 nanoparticles by a chemically-induced transition method in FeCl2 solution, Cu modification was attempted by adding CuCl/NaOH or CuCl2/NaOH to the solution. The as-prepared products were characterized using VSM, TEM, EDS, XRD, and XPS. When adding a NaOH solution with a certain concentration, the components of the as-prepared products changed in relation to the copper salt used. When CuCl 2.5 × 10-3 M was used, γ-Fe2O3/CuFeO2 composite nanoparticles coated by FeCl3·6H2O and with an average size of 11.47 nm were formed. When the CuCl concentration increased to 5 × 10-2 M, a mixture of γ-Fe2O3/CuFeO2 and Cu (OH)Cl nanoparticles was formed. When 5 × 10-2 M CuCl2 was used, the final product contained γ-Fe2O3 nanoparticles, coated with FeCl3·6H2O, and Cu (OH)Cl nanoparticles. The magnetization of the as-prepared products depends on the content of the γ-Fe2O3 and CuFeO2 ferrites.
Analysis of Influence of High Temperature Homogenizing on UV Transmittance of Quartz Glass
Authors: Shao Zhu Feng , Jia Ya Nan , Rao Chuan Dong , Xiang Zai Kui , Sui Mei , Wang Yu Fen , Bao Yi Wang
Published: February 2016

Synthetic quartz glass is an excellent transmittance material in ultraviolet (UV), visible and near-infrared bands. Homogenization process to synthetic quartz glass optical elements is done in order to make the composition and structure more uniform. The homogenization temperature is above 1800°C. After high-temperature homogenization, the UV transmittance of quartz glass appears a certain extent of decline in the edge partition., After high temperature homogenization process, it is found that the closer the layer to the graphite vessel, the stronger influence on UV transmittance will be. This conclusion is made by comparing the UV transmission of the quartz glass in different layers. Furthermore, the factors affecting the UV transmittance is also analyzed in this article.
Preparation Process of Glass Membrane Using Non-Solvent Induced Phase Separation
Authors: Zhang Ya Bin , Pan Guang You , Zhao Ya Ping , Xu Jia Wei , Feng Hai Tao
Published: February 2016

The glass membrane was fabricated by non-solvent-induced phase separation (NIPS) and sintering technique. The preparation process was studied. PVDF was dissolved into DMAc completed. Subsequently, the used glass powder was added into above aqueous solution. The obtained slurry was tape-casted and a green membrane formed. The green membrane was immersed into coagulation bath. The exchange between DMAc and water in coagulation bath took place, and PVDF-containing glass membrane was obtained. The membrane was calcined at different temperature, and the glass membrane was prepared. In order to evaluate the porosity of membrane, many factors including water content in coagulation bath, PVDF content in slurry, coagulation bath temperature and calcination temperature were studied. The viscosity of slurry and shrinkage of membrane after calcination were also studied.
Reaction Mechanism of Iron-Rich Magnesia-Corundum Composites at 1420°C
Authors: Zhang Hao Bo , Li Yong , Sun Jia Lin , Cao Shuo , Sun Yong Qiang , Li Yan Jing , Gao Chang He , Zhang Ji Li
Published: February 2016

Specimens were prepared by using iron-rich magnesia and high-pure magnesia as the main starting materials, and introducing fused corundum of 3%(in mass), 6%, 9%, 12%, 15% respectively and sintered at 1420°C.The samples were characterized by XRD and SEM. The results show that in-situ synthesized composite spinel solid solution were formed in the reaction between iron-rich magnesia and fused corundum. Iron oxides play a key role on the formation of spinel solid solution. When fused corundum was added in a certain particle size, the material showed core-shell structure. Outer layer of core-shell structure were spinel solid solution and the inside were corundum. These core-shell structure make the synthesis of spinel solid solution bonded periclase material at low temperature happen.
ERT Imaging of Graphite Electrically Conductive Concrete
Authors: Huang Bo Sheng , Qin Lei , Ren Hong Wei , Hua Zheng Xiao , Tian Kai Ge
Published: February 2016

In recent decades, Electrical Resistance Tomography (ERT) has become a research focus. The application of ERT in practical engineering is still in the research stage, due to the resistivity is very high and not steady, limiting its development. The influencing factors of Graphite Electrically Conductive Concrete (GECC), such as the dosage of graphite, curing age, moisture content and so on, have been analyzed. A set of ERT system of GECC has been proposed and designed based on PXI platform. This paper mainly shows experiments on ERT of GECC structure. The targets given with defects have been used for imaging. By examining, the law of the GECC imaging in different conductivity matrix has been got. Meanwhile, this paper determines the resistivity threshold in the ERT system, and validates the detection accuracy of the model with defects.
Effect of F-S Mineralizer on the Calcination of Recycled Cement Clinker Produced from Waste Concrete
Authors: Ai Hong Mei , Zhu Su Feng , Liu Xiao Qing
Published: February 2016

The recycled cement production, utilizing all components of the waste concrete without separation treatment as raw materials, provides an effective method for the high value-added resource recovery of waste concrete. However, as fine aggregate (sand) is the main siliceous component in the recycled cement raw materials prepared from waste concrete, its excessive high-crystalline silica content negatively impacts the burnability of raw meal and the property of clinker. By comparing and analyzing the results of burnability test, XRD patterns of clinker and compression strengths of cement paste, this paper attempts to explore the effect of F-S mineralizer on the calcination of recycled cement clinker produced from waste concrete. It could be concluded that F-S mineralizer has a significant improvement on the burnability of recycled cement raw meal, and the f-CaO content decreases with the mineralizer dosage rising. Moreover, in the case of calcination temperature at 1350°C, F-S mineralizer contributes to the enhancement of compression strength of recycled cement paste. Early high-strength minerals ( and C11A7⋅CaF2) are prime motivator to early strength increment, while long-term strength benefits from mineralizer’s improving on hydration activity of silicate mineral in clinker.
Influence of Nitrogen Content on Properties of CrN Coatings Deposited by Single Target Magnetron Sputtering
Authors: Zhang Hao , Shang Jin , Luo Chen Gang , Wu Long Qing , Duo Shu Wang
Published: February 2016

CrN coatings with different nitrogen (N) content were deposited successfully on the 304 stainless steel, using the single direct-current reactive magnetron sputtering target. The surface and section morphologies, composition, phase structure, hardness and adhesion of CrN coatings were studied systematically by SEM, EDS, XRD, a digital micro-hardness tester and a multi-functional tester for material surface properties. Results indicated that deposition rate of CrN coatings declined with the increase of N2 flow percentage. At the high argon gas pressure, the surface morphology grew via a pyramidal mode, but the surface grain shape of CrN coatings changed from stacking of sheets to looser globular structure to denser texture with the ever-increasing nitrogen pressure in a fixed total pressure. The phases in low N content coating were mostly Cr2N and a small amount of metal Cr while CrN phase existed in high N content coatings, and the crystal preferred orientation changed significantly with the varying N2 flow rates. Appropriate N content can improve the comprehensive performance of CrN coating, the increase of N content contributed to the enhancement of coating compactness and the formation of CrN phase, which can account for the phenomenon that coating hardness improved and coating adhesion dropped weakly when N content was increasing.
Effects of Diluent on Mechanical Properties of Hollow Glass Microsphere Reinforced Epoxy Resin Composite
Authors: Geng Hai Tao , Liu Jia Chen , Ren Sue
Published: February 2016

In order to improve the mechanical properties of hollow glass microspheres (HGMs) reinforced epoxy resin composite, diluent was added in the system of epoxy resin. The results revealed that more HGMs can be filled in the epoxy resin when appropriate amount diluent was added in the system, thus composite with relative low bulk density 0.70g/cm3 and high compressive strength 71.85MPa was obtained. It was due to that the diluent reduce the viscosity of the epoxy resin, which ensures uniform wetting of the fillers and enables more HGMs to be filled in resin. Besides, addition of diluent improved the adhesive strength between the epoxy resin and HGMs, making the composite having a relative high specific strength and can be used in weight sensitive filed.
PMAA-g-CS/Loess Composite for Removing Lead Ions
Authors: He Yu Feng , Wang Yin , Qian Wen Zheng , Yan Gui Fang , Wang Rong Min
Published: February 2016

Lead is a toxic heavy metal that has caused serious public health problems. It is necessary to find a cost effective method to deal with wastewater containing lead. In this paper, a novel composite polymer adsorbent, poly (methacrylic acid)-grafted chitosan /Loess composite (PMAA-g-CS/LC) was prepared through graft copolymerization reaction of methacrylic acid and chitosan in the presence of loess. The polymer adsorbent (PMAA-g-CS/LC) was characterized and applied to remove lead ions. It was found that the removal rate of Pb (II) reached to 99%. Adsorption dynamics were consistent with pseudo-second-order kinetic model and isotherm model can meet the Langmuir isotherm model.
MLD Method for the Determination of Major Components in MgO-Cr Refractory Products
Authors: Lu Juan Juan , Liu Yu Bing , Ren Jian Xing , Han Wei
Published: February 2016

In this paper a novel approach is presented for determination of the main components in MgO-Cr refractory material. With the approach, the intensity conversion of fused sample at different dilution ratios can be obtained by establishing the correlation between elements’ intensity and dilution ratio. MgO-Cr refractory material is fused hardly and the dilution ratio requires more than 20 in XRF analysis. Nevertheless, high dilution can reduce the detection sensitivity of low content elements. Using the technology of intensity conversion at different dilution ratio in this paper, a calibration curve was obtained with different dilution ratios. In this method, we obtained a calibration curve successfully and got the satisfactory results for MgO-Cr refractory which was fused well. The new method suggests consistent accuracy and precision with standard method, and it can also simplify the preparation process of samples. The approach shows high sensitivity, good accuracy and precision, meanwhile, it reduces the technical difficulty and labor intensity greatly in analysis method.
The Frictional Contact Problem of a Rigid Stamp Sliding over a Graded Medium
Authors: Guler M.A. , Ozturk M. , Kucuksucu A.
Published: February 2016

In this study, the contact problem for a graded elastic half-plane in frictional contact with a rigid stamp is considered. The plane contact problem is assumed to be linear elastic and the Poisson's ratio is assumed to be constant. Analytical formulation of the study includes Fourier transforms of the governing equations and boundary conditions. The resulting integral equation is solved numerically. Contact pressure, in-plane stress and the stress intensity factor at the sharp edges of the contact are evaluated and demonstrated for various stamp profiles. The results are compared with a closed form solution for homogeneous isotropic half-plane indented by rigid stamps. The effects of the nonhomogeneity parameter, coefficient of friction and stamp profiles on the contact and in-plane stresses are analyzed in detail.
Microstructure and Tribological Properties of a Material with Cementite Eutectic Applied for Metallurgical Rolls
Authors: Rożniata Edyta , Krawczyk Janusz , Dąbrowski Robert , Madej Marcin , Frocisz Łukasz , Pacyna Jerzy
Published: February 2016

Three prototype metallurgical rolls were produced on the basis of G200CrNiMo4-3-3 material. The method applied for the microstructure forming was different for each roll: the roll marked WOT – as cast state (without a modification and heat treatment); the metallurgical roll marked WMT – during its casting the FeCaSi deoxidizing was applied and then modification by a complex inoculant and argoning; the metallurgical roll marked WNT – subjected to a heat treatment (incomplete normalizing).The mentioned above differences in the technology of making rolls caused changes in their microstructure.The cementite eutectic and pearlitic matrix occurred in each roll. The main differences in the microstructure of cast steel rolls concerned a morphology of precipitates of hypereutectoid cementite. In the WOT roll cementite was mainly in the Widmannstӓtten system. Precipitates of hypereutectoid cementite in the WMT roll occurred along grain boundaries of primary austenite. A large fraction of spheroidal hypereutectoid cementite, precipitated in the whole volume of the primary austenite grain, appeared in the WNT roll. The microstructure influenced the rolls hardness and was equal 260 ÷ 350 HBW.Tribological investigations indicated decreasing the abrasive wear resistance with increasing the hypereutectoid cementite fraction within the primary austenite grains.
Researches on the Production of Conductive Aluminium-Graphene Composites
Authors: Knych Tadeusz , Mamala Andrzej , Kwaśniewski Paweł , Kiesiewicz Grzegorz , Kawecki Artur , Smyrak Beata , Gniełczyk Marek , Korzeń Kinga , Sieja-Smaga Eliza
Published: February 2016

All over the world, intensive research is being conducted on the development of new conductive materials to be used in power engineering. The objective of this research is to increase electrical conductivity in wire and cable materials, and consequently, to increase line current-carrying capacities and reduce losses in electric energy transfer. Today, the expectations in the power engineering sector concentrates on conductive materials with electrical conductivity higher than conductivity of base materials, i.e. aluminum. The scientific discovery of the recent years, graphene, one of carbon allotropic variants with a very high electrical and thermal conductivity and mechanical strength, creates great possibilities to design and manufacture new materials, with super-standard functional properties. Graphene, can be a new kind of “alloy additive” to aluminum, which can significantly change their electric and another properties.This article focuses attention on the possibilities of graphene and aluminum synthesis. The researches was made over the different methods of producing these materials, in particular: chemical synthesis consisting in the combination of liquid metal with graphene into a form suitable for further processing in the processes of forming into wires. The article presents the results of mechanical properties and structural studies of aluminum-graphene composites.
Protective Coatings on Steel Dies for Wax Injection Process
Authors: Nawrocki Jacek , Szczech Tomasz , Poreba Marek , Motyka Maciej , Ziaja Waldemar , Sieniawski Jan
Published: February 2016

Protective coatings are used today in many applications for reducing friction and wear of tools in hot-working process e.g. metal die casting, hot forging, metal die plastics injection. The main goal of undertaken investigation was to evaluate usability of those coatings for improving wear resistance of metal die applied in investment casting process for wax injection. The (Ti,Al)N and (Al,Cr)N PVD coatings were deposited onto X37CrMoV5-1 hot-work tool steel and their mechanical and tribological properties are characterized in the paper. Based on the results of microscope examinations, scratch test, hardness measurement the similar properties of (Ti,Al)N and (Al,Cr)N coatings were found. Moreover it was established that type of steel surface machining before coating deposition, i.e. grinding, electrical discharge machining (EDM) and milling, did not affect coating properties. Thin coatings replicate steel base roughness parameters as Ra, Rz and Rmax with over 95% of correlation. Based on tensile test results of wax/coated steel samples and wax/uncoated steel samples the lowest wax adhesion to (Ti,Al)N coating was confirmed.
Effect of the Addition of Glassy Carbon on the Structure and Properties of ZrO2-Y2O2 Coatings
Authors: Richert Maria , Nejman Ilona , Leszczyńska-Madej Beata , Zawadzka Paulina , Smolik Jerzy
Published: February 2016

The effect of the addition of glassy carbon on the structure and properties of ZrO2-Y2O2 coatings deposited at the graphite substrate has been investigated. The coatings were deposited by plasma spraying method in an industrial company Plasma System SA Silesian Siemianowice using MIM40 equipment. The microstructure of coatings was investigated by light microscopy (MO), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Abrasion was carried out with the use of tribological tester Ducom by pin-on-disc method. The results of investigations showed that the addition of the glassy carbon into coatings materials has increased microhardness and resistance against the wear.
Electrochemical Deposition of Selenium on Copper
Authors: Kołczyk Karolina , Kowalik Remigiusz , Mech Krzysztof , Żabiński Piotr
Published: February 2016

The present work concerns studies aiming at determination of optimal parameters of obtaining selenium coatings on a copper substrate through the cathodic reduction from sulphate and citrate solutions. The voltammetric analysis was performed in selected solutions to define electrode reactions within the examined range of potentials as well as an influence of pH on their kinetics. The range of potentials in which selenium is reduced to Se0, and then to Se2- was determined. The next stage was performing several electrolysis, where the working electrode was copper. It was to define an influence of citric acid, sodium sulphate, electrolyte pH and the electrolysis potential on the quality of the obtained coatings. The coatings were analysed with the use of X-ray spectrofluorimetry, X-ray diffraction and scanning electron microscopy.
Investigation of Solidification Process of As-Cast ADC12 in Sand Molds with Different Pouring Conditions by Temperature Field
Authors: Khanh Pham Mai , Hai Nguyen Hong , Khanh Dang Quoc , Bach Dao Hong
Published: February 2016

An investigation of solidification process of as-cast ADC12 aluminum alloy in sand molds with different pouring conditions by temperature field was discussed in the present study. The ADC12 aluminum alloy was investigated in quarzt sand mold and chromite mold using sodium silicate binder with hardening by CO2 gas under atmospheric and low vacuum conditions. Mechanical properties results indicated that a chromites mold under low vacuum condition has the optimal value. Thermal diffusivity was determined by finite difference method. The maximum thermal diffusivity was obtained in a chromite mold under low vacuum condition and correspondence to the minimum solidification time field.
The Influence of Process Parameters on Microstructure and Mechanical Properties of PM Al+4 wt. %Cu Alloy
Authors: Tylek Anna , Leszczyńska-Madej Beata , Zygiert Albert
Published: February 2016

Attempts have been made to describe the influence of the process parameters, such as compaction pressure and sintering atmosphere on the microstructure and properties of PM Al4Cu alloy. Homogenous mixtures of Al4Cu elemental powders were achieved by tumbling powders for 30 minutes in the Turbula T2F mixer. The powders were subsequently cold compacted under pressures of: 200MPa, 300MPa and 400MPa in a rigid die on a single action press. The green compacts were sintered in two different atmosphere - nitrogen and vacuum at 600°C for one hour. After that, the samples sintered in nitrogen atmosphere were re-pressed and re-sintered (2p2s) under the same conditions. The green compact and as-sintered densities were measured using the geometric method. Additionally, the Brinell hardness and the bending strength in three point bend test were determined. The microstructure of the samples was also analyzed using both the light microscopy (LM) and scanning electron microscopy (SEM).The obtained results show, that optimal pressing pressure is 300MPa. Increasing pressure to 400 MPa has not a substantial effect on increase of the final sample density. Therefore applying higher compaction pressure (over 300MPa), from the economical point of view, is unnecessary.
Influence of Molybdenum and Boron Addition on Fracture of P/M Parts
Authors: Perek-Nowak Małgorzata , Karwan-Baczewska Joanna
Published: February 2016

Samples made of iron powder with addition of 1.5 and 2% of molybdenum and 0-0.6% of boron were compacted at 600 MPa and sintered at 1200°C for 60 minutes in hydrogen atmosphere after mixing in Turbula mixer. The samples were deformed in a tensile test till rupture. The effect of molybdenum and boron on topography of fracture is discussed. It is noted that the sintering mechanism changes upon addition of boron particles into Fe-Mo alloy. The fractures of the studied samples were observed by means of scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The addition of Mo influences the change of fracture to ductile type. The type of fracture is brittle with Mo and borides segregating to grain boundaries. In the alloys with low concentrations of molybdenum boron induces brittle transgranular fracture.
Friction Stir Welding of Dissimilar Aluminum Alloys
Authors: Kopyściański Mateusz , Węglowska Aleksandra , Pietras Adam , Hamilton Carter , Dymek Stanisław
Published: February 2016

Dissimilar aluminum alloy plates of 2017A-T451 and 7075-T651 with 6 mm thickness were friction stir butt welded. Numerous trials were conducted to determine the conditions that produce the highest weld quality. These parameters were found to be a welding speed of 112 mm/min, a rotation speed of 355 rev/min and a vertical force of 32,8 kN. The weldability and blending of the two materials were evaluated by using macro- and microstructural analysis as well as EDS mapping to show the distribution of main alloying elements within the weld. The effect of material locations, either on the advancing or retreating sides, on the microstructure and mechanical properties was also investigated. Hardness profiles differ substantially for different weld configurations. Regardless of the position of a particular alloy, the weld microstructure was composed of alternating layers of both materials. However, the layers of the 7075 alloy always exhibited smaller grain size and a larger number of secondary phase particles.
Effect of Processing Parameters on Aeration of Reduced Hatinh Ilmenite
Authors: Nguyen Thao Thi , Truong Than Ngoc , Quoc Dang Khanh , Duong Binh Ngoc
Published: February 2016

Aeration step, one of the major stages in the Becher process was carried out on reduced Hatinh (Vietnam) ilmenite in NH4Cl solution and the effect of several processing parameters were thoroughly investigated including the temperature, time, liquid/solid weight ratio (L/S), air flow rate and concentration of NH4Cl solution. The obtained results showed that longer rinsing time, higher liquid/solid ratio and air flow rate facilitated metallic iron rusting. The rusted iron amount increased when the temperature increased and reached the highest value at 70°C. Variation of NH4Cl concentration showed similar impact as that of temperature. The highest amount of rusted iron achieved at 0.5% NH4Cl. Chemical analysis and XRD results indicated that 98% of metallic iron in reduced ilmenite has been transformed to iron oxides at an aeration condition (70°C, 8 h, L/S=7/1, air flow rate = 4 l/min and 0.5% NH4Cl). Consequently, TiO2 content from approximately 60% in the reduced ilmenite increased up to approximately 80% in the aerated rutile.
Application of CVCC Technique for Measuring Electrical Conductivity of Metallurgical Slags and Molten Salts
Authors: Palimąka Piotr , Pietrzyk Stanislaw , Sak Tomasz
Published: February 2016

Electrical conductivity is one of the most important physico-chemical parameters in chemical engineering as well as in the technology of many industrial process. Especially in the metals production by the electrolysis from molten salts or metals recovery from slags in the electric furnaces, where the great energy is needed.In this work the continuously varying cell constant (CVCC) technique for measuring conductivity of non-ferrous slags and molten salts was used. This is high-accuracy technique, which requires no calibration. The technique was verified by measuring conductivity of standard KCl solution and molten KCl. A good agreement was obtained between measured and commonly accepted literature values. The results of measured conductivity of KF-AlF3 melts were compared with data obtained by other authors. It was proved that CVCC technique can measure accurately the electrical conductivity of high-temperature molten salts and metallurgical slags.
Application of Torsion Test for Determination of Rheological Properties of 5019 Aluminium Alloy
Authors: Laber Konrad Błażej , Kawałek Anna , Sawicki Sylwester , Dyja Henryk , Borowski Jacek , Lesniak Dariusz , Jurczak Henryk
Published: February 2016

The paper presents the results of the study aimed at determination of plasticity of hard-deformed aluminium alloy grade 5019 in terms of parameters characteristic for the process of extrusion. The examinations were carried out in hot torsion test. Using the developed mathematical model of the analyzed alloy the mathematical modelling of torsion test was also performed.
Research of the Laboratory Wire Drawing Process of Zinc
Authors: Jabłoński Michał , Knych Tadeusz , Mamala Andrzej , Smyrak Beata , Ciejka Beata
Published: February 2016

The paper present results of the research on the laboratory drawing process of zinc obtained in industrial conditions in the CCR by Properzi method. The force drawing, mechanical properties before and after process was measured and formability limit in drawing process was specified. Because the wire drawing process was on hot (above the recrystallization temperature) the material didn’t work hardening as a function of strain which reduces the ductility and breaking just after the die. The microscopic images of microstructure reveal the presence of large twins recrystallization reflecting the dynamic renewal structure.
Analysis of Extrusion Welding Conditions for AlMg Alloys with High Mg Content
Authors: Wojtyna Alicja , Lesniak Dariusz , Rękas Artur , Latos Tomasz , Zaborowski Krzysztof , Leszczyńska-Madej Beata
Published: February 2016

In the work, an original method and a special modified device is presented enabling to determine welding conditions of hard deformable aluminium alloys. The main advantage of the proposed method is that it simulates conditions occurring in the welding chamber of the porthole dies. The weldability tests were performed for 5754 (3,5% Mg) and 5019 (5,5% Mg) alloys, in a wide range of temperatures and pressures. The microstructure and joints strength were examined. The welding conditions of AlMg alloys that allowed obtaining high-quality joints were determined. The obtained welding stress values will be the basis for extrusion porthole die design.
Effects of Thermal Heat Treatment Parameters on the Properties of WE43 Magnesium Alloy
Authors: Peter Ildiko , Castella Christian , Rosso Mario
Published: February 2016

The WE43 is a Mg-Y-Nd alloy that presents good mechanical properties and an high creep resistance. For these reasons currently is widely used in the aerospace and automotive industries. The setting of the right thermal heat treatment parameters plays a crucial role in determine the microstructure and consequently the mechanical properties of the alloy. With this in mind, the main goal of this work has been that to identify the optimal parameters to achieve a high impact resistance and at the same time, the most suitable choice, to reach also an important cost-saving solution, which is extremely important especially from the industrial point of view.
Research on the Selection of Heat Treatment Parameters of Casting Aluminum Alloy AlSi5Mg Type
Authors: Wiecheć Justyna , Knych Tadeusz , Lachowicz Marzena Małgorzata , Lachowicz Maciej , Koszla Paulina
Published: February 2016

The paper presents research on the effects of magnesium content on electrical and mechanical properties of materials after heat treatment of the casting of aluminum alloys: AlSi5Mg0.3, AlSi5Mg0.8 and AlSi5Mg1. The proposed heat treatment consisted of homogenisation at 535°C during period of the time 8 h, quenched to water and artificial aging at temperatures ranging from 120 to 240°C during period of the time to 24 h. Determination of strength properties were realized by Brinell hardness measurements. Electrical properties are in the form of electrical conductivity. The research program also included analysis of the microstructure of selected alloys.
Arbeitsgemeinschaft: The Kadison-Singer Conjecture
Authors: Marcus Adam W.
Published: February 2016

The solution to the Kadison–Singer conjecture used techniques that intersect a number of areas of mathematics. The goal of this Arbeitsgemeinschaft was to bring together people from each of these fields to support interactions between these areas. While the majority of the talks centered around topics in polynomial geometry, combinatorics, and real algebraic geometry, participants came from areas such as harmonic analysis, convex geometry, and frame theory.
New Perspectives on the Interplay between Discrete Groups in Low-Dimensional Topology and Arithmetic Lattices
Authors: Hamenstädt Ursula , Masbaum Gregor , Reid Alan W. , Venkataramana Tyakal Nanjundiah
Published: February 2016

This workshop brought together specialists in areas ranging from arithmetic groups to topological quantum field theory, with common interest in arithmetic aspects of discrete groups arising from topology. The meeting showed significant progress in the field and enhanced the many connections between its subbranches.
Difference Approximation of Stochastic Elastic Equation Driven by Infinite Dimensional Noise
Authors: Zhang Yinghan , Yang Xiaoyuan , Qi Ruisheng
Published: February 2016

An explicit difference scheme is described, analyzed and tested for numerically approximating stochastic elastic equation driven by infinite dimensional noise. The noise processes are approximated by piecewise constant random processes and the integral formula of the stochastic elastic equation is approximated by a truncated series. Error analysis of the numerical method yields estimate of convergence rate. The rate of convergence is demonstrated with numerical experiments.
Empleo de modelos cartográficos tridimensionales aplicados al estudio Histórico-Artístico del Territorio
Authors: Ruiz Checa José Ramón , Cristini Valentina , Sánchez Duque Mª Isabel
Published: February 2016

In Cuenca district, Spain, at only 150kms south east from Madrid we can find a dense net of watchtowers, dated on the last years of the XII century, scattered all over the territory. These enigmatic constructions, following the results of the presented, research have a Christian origin, due to their control of the territory and bonded with the regulation of the displacements of livestock during the seasons. Have they a military or a civil function? Both of the possibilities are documented… morphological and typological studies have been developed with special attention to cartographical 3d models. The research has opened an interesting horizon about the relations between territory, towers and historical paths, visible in the district during the Reconquest Ages. In conclusion, use of territorial models for archeological research.
La Cueva del Tiempo. Un viaje a nuestros orígenes
Authors: Cuesta Marín Cristina , Barrera Mayo Sergio , Baeza Santamaría Unai
Published: February 2016

The human evolution can be defined as the human being transformation process since our ancestors’ period till current days. It has been a changing process that ended in Homo sapiens, the unique human being that exists in the planet. How have we ended as we are right now? How have we changed? There have been many changes along the time that made us humans. Studying the different archaeological findings and human remains we are able to know and to understand our biological and cultural evolution. The Cave of Time will enable to feel the experience of travelling to the past and living in thousand years ago environments, in order to communicate with our ancestors interactively. This way Atapuerca´s legacy will be transferred to future generations innovatively.
Realidad Virtual para la dinamización de entornos rurales. Un caso práctico: Red Parque Cultural
Authors: Baeza Santamaría Unai
Published: February 2016

In the last few decades, there has been an intense work on the way of promoting and adding value to the cultural, natural and archaeological heritages in rural sites. At this point, there is a new point of view searching new tools closer to the society, which enable to show their wealth, while observing and preserving all its essence. Among these tools, Virtual Reality provides an exceptional instrument in this spirited bet of archaeological and cultural sites managers with excellent exploitation results in some real cases that prove this evidence.