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排序方式: 共有396条查询结果,搜索用时 13 毫秒
101.
Mahmood Moradi Majid Ghoreishi 《The International Journal of Advanced Manufacturing Technology》2011,55(1-4):205-215
In the present study, autogenous laser butt joint welding parameters of Ni-base super alloy Rene 80 has been investigated by using a continuous wave 2.2?kW CO2 laser. The experiments were performed based on the response surface methodology as a statistical design of experiment approach in order to investigate the effect of parameters on the response variations, achieving the mathematical equations and predicting the new results. Laser power (1,000?C2,200?W), welding speed (120?C360?cm/min), laser beam focal point position (?0.5?C0.5?mm) and inert gas pressure (0.2?C1?bar) were considered as the input process variables while welding surface width (W1), welding pool area (A), width of the weld-bead at the middle depth (W2), undercut welding and drop of welding were considered as the five process responses. Analyzed by statistical techniques, the results show that the welding bead profile is influenced by the laser heat input and input laser process parameters. Welding speed is known as the most important parameter with the reverse effect on process outputs. Inert gas pressure is the next significant parameter, and higher gas pressure causes welding geometry defects. Laser power has a direct influence on all investigated responses. 相似文献
102.
S. Toghyani F. Moradi Nafchi E. Afshari K. Hasanpour E. Baniasadi S.A. Atyabi 《International Journal of Hydrogen Energy》2018,43(9):4534-4545
In this study, the effect of clamping pressure on the performance of a proton exchange membrane fuel cell (PEMFC) is investigated for three different widths of channel. The deformation of gas diffusion layer (GDL) due to clamping pressure is modeled using a finite element method, and the results are applied as inputs to a CFD model. The CFD analysis is based on finite volume method in non-isothermal condition. Also, a comparison is made between three cases to identify the geometry that has the best performance. The distribution of temperature, current density and mole fraction of oxygen are investigated for the geometry with best performance. The results reveal that by decreasing the width of channel, the performance of PEMFC improves due to increase of flow velocity. Also, it is found that intrusion of GDL into the gas flow channel due to assembly pressure deteriorates the PEMFC performance, while decrease of GDL thickness and GDL porosity have smaller effects. It is shown that assembly pressure has a minor effect on temperature profile in the membrane-catalyst interface at cathode side. Also, assembly pressure has a significant effect on ohmic and concentration losses of PEMFC at high current densities. 相似文献
103.
Alice Mesnage Mohamed Abdel Magied Pardis Simon Nathalie Herlin-Boime Pascale Jégou Guy Deniau Serge Palacin 《Journal of Materials Science》2011,46(19):6332-6338
The grafting of biocompatible poly(hydroxyethyl) methacrylate (PHEMA) by a very simple method onto titanium dioxide nanoparticles
is reported. The selected grafting process is based on the chemical reduction of diazonium salts by reducing agents in presence
of the vinylic monomer. As previously demonstrated on flat surfaces, it leads to strongly grafted and stable polymer films
and has many advantages residing in a short one-step reaction occurring at atmospheric pressure, ambient air and room temperature
in water. TiO2 nanoparticles were synthesized by laser pyrolysis, giving nanoparticles with controlled size and composition. The coating,
the composition, the chemical structure, and the grafted PHEMA quantities of the resulting products were investigated by Transmission
electron microscopy, Infrared-attenuated total reflection, X-ray photoelectron spectroscopy, and Thermogravimetric analysis.
It was demonstrated that the PHEMA shell was successfully chemically grafted onto the surface of the TiO2 core without any significant influence on the morphology of the nanoparticles. 相似文献
104.
Pardis Mohammadzadeh Mehdi Shafiee Ardestani Sobhan MortazaviDerazkola Ahmad BitarafanRajabi Seyedeh Masoumeh Ghoreishi 《IET nanobiotechnology / IET》2019,13(6):560
While cancer is the leading cause of human''s deaths worldwide, finding an imaging agent which can detect cancer tumours is needed for cancer diagnosis. In the present study, PEG‐citrate dendrimer‐G2 was used as a nano‐carrier of FITC dye and Iohexol to help passive targeting and uptake of both imaging agents in cancer cells/tumour in vitro and in vivo. Dendrimer was synthesisedand the product characterised using LC‐MS, FT‐IR, DLS, ELS, AFM, and 1 HNMR. After FITC loading into dendrimer, MTT was performed to determine the cytotoxicity of formulation on HEK‐293 and MCF‐7 cells. In vitro imaging using dendrimer‐FITC was done via fluorescent microscope thereafter. Moreover, CT imaging using Iohexol was employed to show the targeting nature and ability of the complex to use as imaging agent in vivo. Data yielded in this study corroborate the notion that the promised dendrimer was synthesised properly and had no toxicity along with FITC on normal cell. Furthermore, CT and fluorescent images showed the targeting nature and imaging ability of Iohexol/FITC loaded dendrimer in vitro and in vivo. Overall, results showed promising characteristics of the novel complexes using dendrimer‐G2 both in vitro and in vivo.Inspec keywords: drug delivery systems, cellular biophysics, molecular biophysics, fluorescence, cancer, tumours, drugs, nanomedicine, biomedical materials, dyes, toxicologyOther keywords: imaging agent, cancer tumours, cancer diagnosis, PEG‐citrate dendrimer‐G, FITC dye, cancer cells, FITC loading, vitro imaging, dendrimer‐FITC, CT imaging, targeting nature, promised dendrimer, fluorescent images, imaging ability, Iohexol/FITC 相似文献
105.
Isaac Moradi 《Energy》2009
The aim of this study was to develop a new and automatic method for controlling the quality of daily global solar radiation, Gd, using sunshine duration hours. The new method has three levels of tests: first, Gd is compared against daily extraterrestrial radiation that is received on a horizontal surface (0.03×God?Gd<God); second, Gd should only exceed by a small amount of the daily clear sky irradiation that is observed under highly transparent clear skies (Gd<1.1Gcd); and third, the method uses a series of persistence checks that utilize the relation between daily global solar radiation and relative sunshine duration hours. The method is capable of identifying systematic and non-systematic errors and its ability has been shown in three different climates including semi-arid, coastal humid and very arid climates. 相似文献
106.
In this study acidic sludge was refined by a novel method that involves neutralization and extraction of organic compound by a waste solvent. Study on refined sludge indicated that sulfuric acid and major of impurities were removed from sludge. Moreover, resin and asphaltene and accordingly ductility of sludge increased. In continue, different amounts of sludge residue were added to vacuum bottom for bitumen preparation. Test results indicated that sludge residue improved mechanical property and elastic modulus of bitumen. Thermal tests illustrated fine thermal stability of blends at production temperature. Also, aging data described reasonable durability for samples. Consequently, by this approach not only hazardous acidic sludge was eliminated from environment but also it improved mechanical properties of bitumen. 相似文献
107.
Iraj Khodadadi Seid Mehdi Seyedain Ardebili Orang Eyvazzadeh Kaveh Zargari Mohammadreza Moradi 《Food Analytical Methods》2014,7(6):1213-1218
Controlling of added iron to fortified flours is very important, and the common method is spot test inaccurate method. In this study, we invented a new method based on a computer vision system. We also compared the accuracy of this method and the spot test with atomic absorption spectroscopy. In new method, ferrous sulfate particles in the samples were oxidized, and some red spots were formed on the surface of samples. The captured images from samples were changed to binary images and analyzed using the Clemex Vision 3.5 software. After processing of image, the number of colored spots and the area of spots were determined. The calibration curves were drawn, and in order to compare the sensitivity of the new method with spot test, 33 samples were selected randomly, and the amounts of added iron were detected using new method, spot test, and atomic absorption. We used t test and linear regression tests with a confidence interval of 95 % to compare the results. Results showed that there was a higher correlation (R 2?=?0.988, p?<?0.001) between new method and atomic absorption method in comparison with spot test (R 2?=?0.501, p?<?0.001). Therefore, spot test and atomic absorption can be replaced by an accurate but inexpensive method. 相似文献
108.
Multi-species biofilms are found in various bacterial habitats and have industrial relevance. These complex bacterial communities have synergetic effects, unlike a single species. Therefore, it is critical to evaluate these complex communities as a whole. Here, the inhibitory effect of single- and dual-species biofilms of Vibrio neocaledinocus sp. and Pseudoalteromonas piscicida for A36 carbon steel corrosion was investigated. The results demonstrated that the synergistic interactions of the monoculture increased the overall biomass production of the dual-species biofilm, but the growth rate was reduced in the presence of the dual-species culture due to a lack of nutrients. Field emission scanning electron microscopy images also confirmed the development of biofilms—they became more homogenized via exposure time in both the mono- and dual-species cultures. The corrosion resistance of A36 carbon steel positively increased because of the dual-species interactions. This reached the highest value after four weeks of exposure. The highest corrosion inhibition efficiency of 99.8% was achieved in the dual-species cultures. Microbial community analysis revealed the high relative abundance of Pseudoalteromonas piscicida during the initial days of exposure, demonstrating the dominant role of this bacterium in the biofilm structure. 相似文献
109.
The kinetic and thermodynamic effects of three typical low‐dosage imidazolium‐based ionic liquids (ILs) on methane hydrate formation and dissociation were investigated, considering the anion nature and subcooling and/or overpressure driving forces. Isochoric hydrate formation and dissociation data were obtained by the modified slow step‐heating method. ILs proved to have a dual effect on both formation and dissociation of methane hydrate including thermodynamic and kinetic inhibition. Kinetic modeling of methane hydrate inhibition by low‐dosage ILs was performed. Kinetic analysis showed that IL inhibitors mainly cause a delay in the nucleation or hydrate growth step. The related inhibition mechanism was resolved regarding the ionic nature and electrostatic interactions of ILs with water molecules. Two binomial exponential kinetic relations were derived and used for simple methane hydrate formation in the presence of ILs as kinetic hydrate inhibitors. The proposed relations can serve for a quick estimation of the nature, extent, strength, and effectiveness of ILs on various gas hydrates. 相似文献
110.