American Journal of Materials Science最新文献_第9页

Hydrotalcite/unsaturated Carboxylic Acid Systems as Coagents in Ethylene-Propylene Copolymer Vulcanization 水滑石/不饱和羧酸体系在乙烯-丙烯共聚物硫化中的助剂作用

American Journal of Materials Science Pub Date : 2012-08-31 DOI: 10.5923/J.MATERIALS.20110102.13

M. Maciejewska, Alicja Krzywania-Kaliszewska, M. Zaborski

{"title":"Hydrotalcite/unsaturated Carboxylic Acid Systems as Coagents in Ethylene-Propylene Copolymer Vulcanization","authors":"M. Maciejewska, Alicja Krzywania-Kaliszewska, M. Zaborski","doi":"10.5923/J.MATERIALS.20110102.13","DOIUrl":"https://doi.org/10.5923/J.MATERIALS.20110102.13","url":null,"abstract":"The aim of this work was to study the activity of several hydrotalcite/unsaturated acid systems in the peroxide crosslinking of ethylene-propylene copolymer (EPM). Allylmalonic, citronellic, crotonic, itaconic, sorbic and undecylenic acids, as well as monoallyl maleate, were applied to ensure the activity of hydrotalcite in the peroxide vulcanization of EPM. In this article, we discuss the effect of the obtained coagents with respect to their particle size and tendency to agglomerate, as well as the effect of the applied type of unsaturated acid on the vulcanization kinetics of rubber compounds. The influence of hydrotalcite/unsaturated acid systems on the crosslink density, the mechanical properties of the vulcanizates and their stress relaxation tendency under external deformation were also studied. Hydrotalcite/unsaturated acid systems seem to be active as coagents in the crosslinking of EPM with peroxide. The type of unsaturated acid considerably influences the activity of hydrotalcite toward the ethylene-propylene copolymer. The application of such coagents increases the crosslink density of the vulcanizates and improves their mechanical properties.","PeriodicalId":7420,"journal":{"name":"American Journal of Materials Science","volume":"6 1","pages":"81-88"},"PeriodicalIF":0.0,"publicationDate":"2012-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84329885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6

Synthesis, Structural and Magnetic Characterization of Ni-Doped ZnO Diluted Magnetic Semiconductor ni掺杂ZnO稀释磁性半导体的合成、结构及磁性表征

American Journal of Materials Science Pub Date : 2012-02-01 DOI: 10.5923/J.MATERIALS.20120201.09

R. Elilarassi, G. Chandrasekaran

{"title":"Synthesis, Structural and Magnetic Characterization of Ni-Doped ZnO Diluted Magnetic Semiconductor","authors":"R. Elilarassi, G. Chandrasekaran","doi":"10.5923/J.MATERIALS.20120201.09","DOIUrl":"https://doi.org/10.5923/J.MATERIALS.20120201.09","url":null,"abstract":"In the present work, Zn1−xNixO (x = 0.02, 0.04, 0.06 and 0.08) nanoparticles have been synthesized using sol-gel auto-combustion method. The structural and magnetic properties of the Ni-doped ZnO samples annealed at 800oC were characterized by Thermogravimetry/Differential thermal analysis (TG/DTA), X-ray diffractometer (XRD), Scanning electron microscope (SEM), FTIR spectrophotometer, Vibrating sample magnetometer (VSM) and Electron paramagnetic resonance (EPR) spectroscopy. Thermal analysis of as–prepared Zn0.98Ni0.02O sample shows that the synthesis process undergoes two stage weight losses before yielding Zn0.98Ni0.02O nanoparticles. Structural analysis using XRD reveals the formation of hexagonal wurtzite structure. SEM micrographs of Zn0.98Ni0.02O show the presence of spherical nanoparticles and the formation of well defined pores in the sample. FTIR study confirms the formation of ZnO with the stretching vibrational mode around 525 cm-1. VSM measurement of sample (Zn0.96Ni0.04O) shows the hysteresis loop at room temperature confirms the ferromagnetic property of the sample. EPR spectra of the nickel doped ZnO samples suggest that the exchange interaction between Ni2+ ions results in the ferromagnetic nature of the samples.","PeriodicalId":7420,"journal":{"name":"American Journal of Materials Science","volume":"29 1","pages":"46-50"},"PeriodicalIF":0.0,"publicationDate":"2012-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79166346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 40

Dimensional and Geometric Deviations Induced by Milling of Annealed and Hardened AISI H13 Tool Steel 退火淬火后AISI H13工具钢铣削引起的尺寸和几何偏差

American Journal of Materials Science Pub Date : 2012-02-01 DOI: 10.5923/J.MATERIALS.20120201.03

J. Luiz, S. Ribeiro, Steve B. Diniz, J. Rubio, A. Abrão

{"title":"Dimensional and Geometric Deviations Induced by Milling of Annealed and Hardened AISI H13 Tool Steel","authors":"J. Luiz, S. Ribeiro, Steve B. Diniz, J. Rubio, A. Abrão","doi":"10.5923/J.MATERIALS.20120201.03","DOIUrl":"https://doi.org/10.5923/J.MATERIALS.20120201.03","url":null,"abstract":"The principal goal of this paper was to investigate the influence of tool grade, cutting speed and feed rate on the dimensional (length, diameter and radius) and geometric (parallelism and angularity) deviations obtained after milling AISI H13 hot work die steel in both annealed and hardened conditions using three indexable insert grades: two coated tungsten carbides tools and one cermet tool. The results indicated that lower dimensional deviations were obtained for the external features when up-milling the softer material. Tool grade did not seem to drastically affect external dimensional errors. The dimensional deviations for the internal features were lower when up-milling the hardened steel. The cermet tool was re- sponsible for tighter tolerances when milling the annealed steel, whereas the PVD-coated tungsten carbide tool gave the best results when machining the hardened steel. The parallelism results indicated that tighter tolerances were obtained when milling with the PVD-coated carbide tool. Finally, the angular deviation was lower when down-milling the annealed material with the cermet tool.","PeriodicalId":7420,"journal":{"name":"American Journal of Materials Science","volume":"168 1","pages":"14-21"},"PeriodicalIF":0.0,"publicationDate":"2012-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88508991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 8

Tartrazine Dye and Bovine Serum Albumin: the Influence of pH on Adsorption Process 酒黄石染料与牛血清白蛋白:pH对吸附过程的影响

American Journal of Materials Science Pub Date : 2012-02-01 DOI: 10.5923/J.MATERIALS.20120201.04

J. B. Brito, G. P. Aguiar, J. C. Flores, Josmary R. Silva, N. C. Souza

引用次数: 3

Effect of Load and Sliding Velocity on Friction Coefficient of Aluminum Sliding Against Different Pin Materials 载荷和滑动速度对铝与不同销材料滑动摩擦系数的影响

American Journal of Materials Science Pub Date : 2012-02-01 DOI: 10.5923/J.MATERIALS.20120201.05

D. M. Nuruzzaman, M. Chowdhury

引用次数: 49

Impacts of Heat Treatment on the Electrochemical Properties of AA3003 expose to 0.1M Hydrochloric Acid Media 热处理对0.1M盐酸介质中AA3003电化学性能的影响

American Journal of Materials Science Pub Date : 2012-02-01 DOI: 10.5923/J.MATERIALS.20120201.10

K. Okeoma, I. O. Owate, Emeka Emanuel Oguzie, I. M. Mejeha

{"title":"Impacts of Heat Treatment on the Electrochemical Properties of AA3003 expose to 0.1M Hydrochloric Acid Media","authors":"K. Okeoma, I. O. Owate, Emeka Emanuel Oguzie, I. M. Mejeha","doi":"10.5923/J.MATERIALS.20120201.10","DOIUrl":"https://doi.org/10.5923/J.MATERIALS.20120201.10","url":null,"abstract":"The impact of heat treatment on the electrochemical corrosion behaviour of control, oven quenched and air quenched samples of Aluminium alloy AA3003 was investigated by observing the changes that occurred in the open circuit potential, potentiodynamic polarization curve, and electrochemical impedance spectra within 0.1M HCl acid environment. The open circuit potential of the oven quenched sample shifted to more negative values, indicating shift into the active states. The cathodic branch of the polarization potential of the air quenched sample shifted into lower current density, indicating resistance to cathodic corrosion. The impedance analysis shows that the heat treatment of the sample facilitated dissolution of the samples in the medium. The calculated double layer capacitance buttresses the fact that the heat treatment caused the samples to be more susceptible to corrosion within the acid medium since the value is higher for heat treated samples. Finally, from the XRD data, heat treatment caused a decreased in peak intensity, size of crystalline particles, and a shift into higher diffracting angles for the particles and elimination of Mn from the crystalline particles that occurred at maximum peak.","PeriodicalId":7420,"journal":{"name":"American Journal of Materials Science","volume":"46 1","pages":"51-58"},"PeriodicalIF":0.0,"publicationDate":"2012-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81134309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Micro-Structural Characterization of Si-SiC Ceramic Derived from C/C-SiC Composite C/C- sic复合材料制备的Si-SiC陶瓷的微观结构表征

American Journal of Materials Science Pub Date : 2012-02-01 DOI: 10.5923/J.MATERIALS.20120201.01

V. Srivastava

引用次数: 16

Structural Transitions of Silicate Nanocrystals in the Glass 玻璃中硅酸盐纳米晶的结构转变

American Journal of Materials Science Pub Date : 2012-02-01 DOI: 10.5923/J.MATERIALS.20120201.07

G. Abdurakhmanov, G. S. Vakhidova

{"title":"Structural Transitions of Silicate Nanocrystals in the Glass","authors":"G. Abdurakhmanov, G. S. Vakhidova","doi":"10.5923/J.MATERIALS.20120201.07","DOIUrl":"https://doi.org/10.5923/J.MATERIALS.20120201.07","url":null,"abstract":"Institute of Power Engineering and Automation, the Uzbek Academy of Sciences, 29 Do'rmon yo'li, Tashkent, 100125 Uzbekistan Abstract The temperature dependences of resistivity and thermopower measurements reveal that nanocrystals of sili- cates in lead-silicate glass of various compositions undergo structural transitions in the temperature range of 800 - 1000 K. The diameter of these nanocrystals estimated from Scherrer's formula is about 0.8 - 1.6 nm and each nanocrystal consists of 8 - 64 unit cells. Structure transitions are detected as sharply maxima of resistivity ρ and thermopower S at temperature T = 800 - 100 K. Lead-silicate glass was doped by RuO2 up to 16 weight% to facilitate the measurements of the ρ and the S. The doped lead-silicate glass has a metal-like behavior at the room temperature: the temperature dependences ρ(T) and S(T) are very slow, the value of the S is typical for metals (few and tens of μV/K). Beyond the maximum of the resistance (tem- perature T > 1000 K) doped lead-silicate glass turns into typical semiconductor having energy gap about 0.05 - 1.5 eV de- pending on the composition of the glass. Anomalous thermal expansion of the RuO2 relict crystals is detected at the tem- peratures of 800 - 1000 K as well.","PeriodicalId":7420,"journal":{"name":"American Journal of Materials Science","volume":"27 1","pages":"37-40"},"PeriodicalIF":0.0,"publicationDate":"2012-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85941683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Effect of Film Thickness on Optical Properties of Tin Selenide Thin Films Prepared by Thermal Evaporation for Photovoltaic Applications 薄膜厚度对光伏热蒸发制备硒化锡薄膜光学性能的影响

American Journal of Materials Science Pub Date : 2012-02-01 DOI: 10.5923/J.MATERIALS.20120201.08

N. Kumar, U. Parihar, Rakesh Kumar, Keyur J. Patel, C. Panchal, N. Padha

引用次数: 68

Shape Controlled Synthesis of Barium Carbonate Microclusters and Nanocrystallites using Natural Polysachharide – Gum Acacia 利用天然皂荚胶合成碳酸钡微团簇和纳米晶

American Journal of Materials Science Pub Date : 2012-02-01 DOI: 10.5923/J.MATERIALS.20120201.02

B. Sreedhar, C. Vani, D. K. Devi, M. V. B. Rao, C. Rambabu

{"title":"Shape Controlled Synthesis of Barium Carbonate Microclusters and Nanocrystallites using Natural Polysachharide – Gum Acacia","authors":"B. Sreedhar, C. Vani, D. K. Devi, M. V. B. Rao, C. Rambabu","doi":"10.5923/J.MATERIALS.20120201.02","DOIUrl":"https://doi.org/10.5923/J.MATERIALS.20120201.02","url":null,"abstract":"Different morphosynthesis strategies for BaCO3 using natural polysaccharide-gum acacia (GA) as templating species are presented. The influence of GA with different functionalities such as -OH, -COOH and -NH2 on the crystalli- zation and structure formation was investigated. Some interesting morphologies, including rods, dumbbell, double-dumbbell and flower like clusters, can be readily generated by using GA as cooperative modifier in the mineralization process, under the conditions of 0.5%, 1% of templating species and at ambient temperature. The modifier GA and its concentration is the key factor in this system. In continuation, morphology was also examined for mixed metal carbonates (Ba-LaCO3, Ba-TbCO3). The possible formation mechanism of the nanocrystallites is discussed. Structural characterization of the syn- thesized materials was investigated by Powder X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Analysis (EDAX), Transmission Electron Microscopy (TEM), Thermogravimetric analysis (TGA) coupled Mass (MS) and Fourier Transform Infrared spectroscopy (FT-IR).","PeriodicalId":7420,"journal":{"name":"American Journal of Materials Science","volume":"83 1","pages":"5-13"},"PeriodicalIF":0.0,"publicationDate":"2012-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81219072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 26