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991.
Effect of the omega‐3 fatty acid plus vitamin E supplementation on subjective global assessment score,glucose metabolism,and lipid concentrations in chronic hemodialysis patients 下载免费PDF全文
992.
In the last decade, technological innovations have resulted in considering distributed generation with heat recovery capability in addition to centralised generation. This work aims to develop a comprehensive model analysing techno-economic parameters of energy supply in an office building. The energy model is developed on the basis of the reference energy system with the linear programming technique. The objective function is the annual value of total costs of the energy supply system. The results of the model for the building of Sharif Energy Research Institute indicate that the most appropriate generation technology is an internal combustion engine of 461 kW and a water boiler of 152 kW. In addition to supplying the final service demand, hot water feeds an absorption chiller of 507 kW to produce cold water. Furthermore, storage systems of hot and cold water are required in order to achieve high load factors in the system. 相似文献
993.
Sayed Mohammad Sahafi Sayed Amir Hossein Goli Meisam Tabatabaei Ali Mohammad Nikbakht Navid Pourvosoghi 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2016,38(7):942-950
Currently, semi-refined and refined vegetable oils are used as a feedstock in biodiesel production. However, criteria such as competition with conventional fossil fuel, economic reasons, shortage supply of food and its social impact on the global scale have somewhat slowed the development of the biodiesel industry. Spent bleaching earth is currently under-utilized by deposition in landfills with no attempt to recover the oil. In this study the waste oil adsorbed on spent bleaching earth, refined soybean oil, and waste cooking oil were evaluated as potential sources of biodiesel production in Iran. Different characteristics of the oil samples, such as fatty acid composition, peroxide, iodine, acid values, etc., were evaluated. A two-step esterification reaction using methanol was conducted to produce biofuel. Subsequently, physicochemical properties of produced biodiesel were analyzed. The oil content in spent bleaching earth was 19.3%, which was lowered to 3.7% using hexane as the solvent. Gas chromatography showed that palmitic, oleic, and linoleic acids were predominantly fatty acids, respectively, and the highest content of saturated acids belonged to waste cooking oil (24%). The acidity of 8.3% was obtained for the oil recovered from spent bleaching earth followed by waste cooking oil (3.6%) and refined soybean oil (0.1%). Totally, the specifications of all biodiesel produced were in the range defined by ASTM D6751 and EN 14214 standards. Since about 2000–3000 tones of spent bleaching earth residual oil is annually dumped and the amount of waste cooking oil produced yearly is 500,000 tones, there is a great potential for Iran to produce biodiesel from waste oils. 相似文献
994.
Hossein Gilani Sajjad Jafari Roozbeh Gholami Ali Habibolahzadeh Mohammad Mirshahi 《Metals and Materials International》2012,18(2):327-333
Aluminum foam has been produced by sintering and dissolution processes using NaCl powders as a space holder. In this research,
glycerin is used as a novel lubricant along with acetone. The effects of the processing parameters including compacting pressure,
sintering temperatures (620, 640 and 650 °C), size, and volume fraction of the space holder, on the physical and mechanical
properties of the produced foams have been investigated. Due to segregation of the Al and NaCl powders at high compaction
pressures, spalling of Al foams was observed. Meanwhile, adding small amounts of acetone and glycerin to the mixture ensures
homogeneity and prevents segregation of dissimilar powders at varying pressure. Moreover, the addition of glycerin provides
an improved homogenous stress distribution within the produced foams during mechanical testing, which in turn halts crack
propagation. Meanwhile, an alternative technique to remove NaCl particles during the dissolution stage has been proposed.
The results showed that high quality foams were successfully produced under a compaction pressure range of 250–265 MPa and
sintering temperature of 650 °C. 相似文献
995.
Reza Rezaee Amir Hossein Mahvi Ramin Nabizadeh Seyyed Abbas Mousavi Afshin Maleki 《Chemical Engineering Communications》2019,206(4):495-508
In this study, four types of mixed matrix membranes were fabricated using polysulfone (as the base polymer) and different contents of graphene oxide (GO) nanosheets (as modifier) through wet phase inversion method. Based on the amounts of GO (0, 0.5, 1, and 2?wt%), the synthesized membranes named as M1, M2, M3, and M4, respectively. The membranes characteristics were evaluated using FE-SEM, FT-IR, and water contact angle measurements. In addition, the performance of the prepared membranes was investigated in terms of basic parameters: filtrate water flux, nitrate removal efficiency, and antifouling properties. Results showed significant improvements of the characteristics of modified membranes with GO. Accordingly, the permeability and hydrophilicity were enhanced and water flux was considerably improved. At operating pressure of 4?bar and nitrate concentration of 110?mg/L, the removal efficiency for unmodified membrane (M1) was 15.5% and for modified M2, M3, and M4 membranes were 22.78%, 39.12%, and 41.37%, respectively. In addition, the results of flux recovery ratio (FRR) showed that the anti-fouling properties of the GO modified membranes were improved due to the increase in membrane surface hydrophilicity. 相似文献
996.
997.
One of the most influential factors in architectural design is creativity. The enhancement of student creativity is a universally sought objective. This research hypothesized that computer-aided design, experience, sketching, physical modeling, learning environment, and images and visual references can serve as powerful tools to stimulate creativity in the architectural design process. It sought to investigate which of these components has the greatest impact on increasing student creativity. A total of 114 bachelor students and 347 master students of Architecture were surveyed using a questionnaire. Data were then analyzed using SPSS and one sample t-test and Friedman test for ranking. Results showed that experience can significantly increase the creativity of students in the architectural design process compared to the other components. 相似文献
998.
A complex finite strip method was used to study the buckling of functionally graded plates (FGPs) under thermal and mechanical (longitudinal, transverse, and shear in-plane) loading. The mechanical characteristics of FGPs were assumed to vary through the thickness, according to power law distribution. The nonlinear temperature distribution in the direction of the plate thickness was assumed according to thermal conduction steady state conditions. In complex finite strip method, the polynomial Hermitian functions were assumed in the transverse direction and the complex exponential functions were used in the longitudinal direction to evaluate the standard and geometric stiffness matrices that have the ability of calculating the critical shear stress in contrast to trigonometric shape functions. The solution was obtained by the minimization of the total potential energy and solving the corresponding eigenvalue problem. In addition, numerical results for FGPs with different boundary conditions were presented and compared with those available in the literature and the interaction curves of mechanical and thermal buckling capacity of FGPs were obtained. 相似文献
999.
Photodynamic therapy (PDT) is an effective treatment method for various types of invasive tumors. The efficiency of PDT treatment depends, to a great extent, on optimal dosimetry of light, the photosensitizer used, and on tissue oxygenation. Fluorescence spectroscopy can be employed for measurement of drug concentration in target tissue and can provide a basis for in vivo evaluation of treatment efficiency. We have developed an integrated system that can be used to determine photosensitizer concentration in vivo based on fluorescence measurements. In our study, we performed fluorescence measurements on colon tumors of Balb/c mice in which CT26 cells were injected subcutaneously in the right flank. 5-Aminolevulinic acid (ALA)-induced protoporphyrin IX (PpIX) was used as the photosensitizer. ALA was administered intraperitoneally at a dose of 200 mg/kg and PpIX fluorescence profiles were followed up to 34 h after ALA administration. Maximum fluorescence intensity was found 8 h after ALA administration. Also, we determined the relationship between PpIX concentration in colon tumor tissue of Balb/c mice and its fluorescence intensity at the peak of the spectrum (635 nm). This was used to determine the PpIX content in the target tissue as a function of time after ALA administration. 相似文献
1000.
Mohammad Goharkhah Shahin Amiri Hossein Shokouhmand 《Journal of Mechanical Science and Technology》2009,23(12):3393-3398
The non-Fourier heat conduction problem in a finite slab is studied analytically. Dependence of thermal conductivity on space
has been considered. The Laplace transform method is used to remove the time-dependent terms in the governing equation and
the boundary conditions. The hyperbolic heat conduction (HHC) equation has been solved by employing trial solution method
and collocation optimization criterion. Results show that the space-dependent thermal conductivity strongly affects the temperature
distribution. A temperature peak on the insulated wall of the slab has been observed due to linear variation of thermal conductivity.
It has been shown that the magnitude of the temperature peak increases with increasing the dimensionless relaxation time.
To validate the approach, the results have been compared with the analytical solution obtained for a special case which shows
a good agreement. 相似文献