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11.
轮胎制造行业大量使用各种纤维帘线,然而纤维帘线的设计、开发和制造是一个非常复杂的过程,工程技术人员通常要开展一系列严谨而且复杂的工作,如建立模型、数据分析、结构设计、样品试制和产品测试等,采取不同的方法和技术措施解决过程中存在的各种问题,最后才能确定帘线制造的最佳方案.有限元分析是解决这种具有挑战性工程技术问题最有效的方法之一.尤其是近年来计算能力和智能工具技术水平的快速发展,促进了有限元分析技术的推广应用. 相似文献
12.
Ibrahim Sevim Fatih Hayat Yakup Kaya Nizamettin Kahraman Sadettin Şahin 《The International Journal of Advanced Manufacturing Technology》2013,66(9-12):1825-1834
In this article, Metal Inert Gas (MIG) weldability of commercially received and aged samples of 6061-T6 and 7075-T651 aluminum alloys was investigated. The welding joints were prepared in ten different combinations. Microstructure, microhardness, EDX, energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD) analyses were used in order to evaluate the effect of aged heat treatment on the performance of welded joints. In addition, the mechanical properties of welding joints were characterized using the tensile and microhardness tests. In conclusion, it was shown that prewelding aging heat treatment improves the mechanical properties of welding joints. 相似文献
13.
Zeynep Karahaliloğlu Murat Demirbilek Mesut Şam Melike Erol‐Demirbilek Necdet Sağlam Emir Baki Denkbaş 《应用聚合物科学杂志》2013,128(3):1904-1912
The design and the development of novel scaffold materials for tissue engineering have attracted much interest in recent years. Especially, the prepared nanofibrillar scaffold materials from biocompatible and biodegradable polymers by electrospinning are promising materials to be used in biomedical applications. In this study, we propose to produce low‐cost and cell‐friendly bacterial electrospun PHB polymeric scaffolds by using Alcaligenes eutrophus DSM 545 strain to PHB production. The produced PHB was characterized by Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared Spectroscopy (FTIR). Nanofibrous scaffolds were fabricated via electrospinning method that has a fiber diameter approximately 700–800 nm. To investigate cell attachment, cell growth, and antioxidant enzyme activity on positively and negatively charged PHB scaffold, PHB surface was modified by plasma polymerization technique using polyethylene glycol (PEG) and ethylenediamine (EDA). According to the results of superoxide dismutase (SOD) activity study, PEG‐modified nanofibrillar scaffolds indicated more cellular resistance against oxidative stress compared to the EDA modification. As can be seen in cell proliferation results, EDA modification enhanced the cell proliferation more than PEG modification, while PEG modification is better as compared with nonmodified scaffolds. In general, through plasma polymerization technique, surface modified nanofibrillar structures are effective substrates for cell attachment and outgrowth. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
14.
Sesame paste (tahin) is produced by milling hulled, roasted, sesame seeds. In this study, a hot‐air roasting process for the production of sesame paste was optimised by response surface methodology (RSM) over a range of air temperatures (120–180 °C) for various times (30–60 min). The colour parameters (L, a and b values), browning index (BI), hardness, fracturability and moisture content of the seeds were used as response parameters to develop predictive models and optimise the roasting process. Increases in roasting temperature and time caused increases in the a and b values and in the BI. The hardness and fracturability of seeds also decreased with increasing roasting temperature and time. The quadratic and linear models developed by RSM adequately described the changes in the colour values and textural parameters, respectively. The result of RSM analysis showed that all colour parameters and textural parameters should be used to monitor the roasting of sesame seeds in a hot‐air roaster. To obtain the desired colour and texture, the optimum roasting range for production of sesame paste was determined as 155–170 °C for 40–60 min. Copyright © 2006 Society of Chemical Industry 相似文献
15.
Since it covers the lateral wall of the mastoid air system, the suprameatal triangle is of importance to otologic surgeons during mastoidectomy. Because of this clinical importance, topographic anatomy of the suprameatal spine and depression was studied on Anatolian skulls. In all, 363 male and 231 female skulls were studied. The most prevalent type of suprameatal spine resembled a crest and was found in both sexes on the right (77.6%) and left (80%) sides. The absence of a suprameatal depression was significantly higher in females (right 9.1%; left 8.7%) than in males (right 1.7%; left 2.5%). Suprameatal depressions were mostly shallow in female subjects, but were mostly observed in males to be at a medium depth or deep. 相似文献
16.
Mehtap Safak Boroglu Sevim Unugur Celik Ayhan Bozkurt Ismail Boz 《Polymer Composites》2011,32(10):1625-1632
This work reports the preparation and characterization of a new anhydrous proton conducting membrane based on poly(vinyl alcohol) (PVA), sulfosuccinic acid (SSA), and 5‐aminotetrazole (ATet) at various stoichiometric ratios. The proton conductivities of membranes were investigated as a function of ATet composition, SSA composition, and temperature. New anhydrous proton conducting membranes were characterized by infrared spectra, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), methanol permeability, and impedance measurements for proton conductivity. TGA showed that the samples were thermally stable up to 150°C. DSC results illustrated the homogeneity of the materials. Mechanical analysis showed that the storage modulus of the PVA–SSA–ATet blend polymer membranes decreased with increasing ATet content. The membranes with higher tetrazole content, or higher acid doping level presented the higher proton conductivity. PVA–SSA–ATet4 can exhibit an anhydrous proton conductivity of 1.7 × 10−3 S/cm at 130°C and the proton conductivity increased with increasing temperature and acid doping level. POLYM. COMPOS., 2011. © 2011 Society of Plastics Engineers 相似文献
17.
Polyphenol oxidase (PPO) was purified from Boletus erythropus using a Sepharose 4B-L-tyrosine-p-amino benzoic acid affinity column. Optimum pH and temperature were found to be 8.0 and 20 °C, respectively, using 4-methylcatechol as a substrate. The enzyme was extremely stable between pH 3.0 and 9.0 after 24 h incubation at 4 °C. B. erythropus PPO was also quite stable between 10 and 30 °C after 4 h incubation. The Km and Vmax values were calculated as 2.8 mM and 1430 U/mg protein by Lineweaver–Burk curve, respectively. The enzyme activity was inhibited by sodium metabisulfite, ascorbic acid, sodium azide and benzoic acid. It was seen that the mushroom PPO was an effective biocatalyst in selected organic solvents, such as dichloromethane, dichloroethane and toluene, when catechin was used as a substrate. All data support that B. erythropus has a highly active PPO, possessing similar biochemical and kinetic characteristics to other plant PPOs. 相似文献
18.
A series of UV-cured organic–inorganic hybrid coating materials containing up to 20 wt.% silica were prepared by sol–gel method from tetraethoxy silane (TEOS) which is used as the primary inorganic precursor, and diallylphenylphosphine oxide monomer (DAPPO), aliphatic urethane diacrylate resin (Ebecryl 210) are employed as the source of the organic components. In addition, methacryloxypropyltrimethoxy silane (MAPTMS) was used as both a secondary inorganic source and a silane-coupling agent to improve the compatibility of the organic and inorganic phases. The DAPPO content in all the coating formulations were from 0 to 20 wt.%. The physical and mechanical properties such as gel content, hardness, adhesion, gloss, contact angle as well as tensile strength were measured. These measurements revealed that all the properties of the hybrid coatings improved effectively, in case of adding the sol–gel precursor and DAPPO monomer content in the hybrid systems. The photo-calorimetric-DSC studies showed that the double bond conversion of the hybrid coatings was faster than the coating materials without silica. The thermal stabilities of the UV-cured hybrid materials were investigated by thermogravimetric analysis. The results showed that the addition of sol–gel precursor and DAPPO into the organic network also improves the thermal-oxidative stability of the hybrid coating materials. The surface morphology was also characterized by scanning electron microscopy (SEM). SEM studies indicated that inorganic particles were dispersed homogenously throughout the organic matrix. 相似文献
19.
A diesel-like fuel, pyrodiesel (PD), was synthesized by a pyrolysis method using soybean oil as starting material. Some physical properties of the material were studied, both neat and in blends with high-sulfur (HSD) and low-sulfur (LSD) diesel fuels, and compared with blends of biodiesel (BD) in fossil fuels. It was observed using different methods that the lubricity of biobased fuels obtained after the transesterification or pyrolysis of soybean oil is superior to LSD and HSD and also that the lubricity of diesel fuels are enhanced when either BD or PD are added. Based on the results reported herein, PD is a viable alternative to BD for use in compression-ignition engines. 相似文献