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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Challenges in Nano and Micro Scale Science and Technology
- نوع مقاله: Journal Article
- کلمات کلیدی: Nanofluid,Ethylene glycol,viscosity,Thermal conductivity,Propylene glycol
- چکیده:
- چکیده انگلیسی: In this paper, the measurement of the viscosity of ZnO in ethylene glycol, propylene glycol, mixture of ethylene glycol and water (60:40 by weight), and a mixture of propylene glycol and water (60:40 by weight) and the thermal conductivity in ethylene glycol and propylene glycol as base fluids in the range of temperature from 25 ºC to 60 ºC are investigated. The results indicate that as the temperature increase the viscosity of nanofluid decrease and the thermal conductivity of both base fluid and nanofluid increase. Several existing models for thermal conductivity and viscosity are compared with the experimental data, and they do not demonstrate good comparison agreement. Finally, some new models for predicting the effective viscosity and thermal conductivity are proposed. Furthermore, the viscosity of the base fluid affects the thermal conductivity variation of the nanofluids. The results indicate that the largest enhancements in thermal conductivity are 15% and 9% for EG and PG as base fluids, respectively.
- انتشار مقاله: 13-07-1392
- نویسندگان: S. Akbarzadeh,M. Farhadi,K. Sedighi,M. Ebrahimi
- مشاهده
- جایگاه : پژوهشی
- مجله: Nanomedicine Journal
- نوع مقاله: Journal Article
- کلمات کلیدی: Breast cancer, Chemotherapy, Crocetin,Doxorubicin, PLGA
- چکیده:
- چکیده انگلیسی: Objective(s): The current study reports investigation of codelivery by PLGA nanoparticles (NPs) loaded with crocetin (Cro), a natural carotenoid dicarboxylic acid that is found in the crocus flower, and Doxorubicin (DOX).
Materials and Methods: Double emulsion/solvent evaporation method was used for preparation of PLGA nanoparticles containing Dox and Cro. Characterizations of prepared NPs were investigated by atomic force microscopy (AFM) and dynamic light scattering analysis. In vitro Cytotoxicity of DOX and Cro loaded PLGA NPs (PLGA-DOX-Cro) on MCF-7 cell line was evaluated using MTT test. Flow cytometry experiments were implemented to distinguish cells undergoing apoptosis from those undergoing necrosis. Furthermore the expression of caspase 3 was examined by western blot analysis.
Results: The prepared formulations had size of 150- 300 nm. Furthermore, PLGA-DOX-Cro nanoparticles inhibited MCF-7 tumor cells growth more efficiently than either DOX or Cro alone at the same concentrations, as quantified by MTT assay and flow cytometry. Studies on cellular uptake of DOX-Cro-NPs demonstrated that NPs were effectively taken up by MCF-7 tumor cells.
Conclusion: This study suggested that DOX-Cro-NPs may have promising applications in breast cancer therapy.- انتشار مقاله: 28-09-1394
- نویسندگان: F. A Langroodi,Z. Hafezi Ghahestani,M. Alibolandi,M. Ebrahimian,M. Hashemi
- مشاهده
- جایگاه : پژوهشی
- مجله: Nanomedicine Journal
- نوع مقاله: Journal Article
- کلمات کلیدی: Breast cancer, Chemotherapy, Crocetin,Doxorubicin, PLGA
- چکیده:
- چکیده انگلیسی: Objective(s): The current study reports investigation of codelivery by PLGA nanoparticles (NPs) loaded with crocetin (Cro), a natural carotenoid dicarboxylic acid that is found in the crocus flower, and Doxorubicin (DOX).
Materials and Methods: Double emulsion/solvent evaporation method was used for preparation of PLGA nanoparticles containing Dox and Cro. Characterizations of prepared NPs were investigated by atomic force microscopy (AFM) and dynamic light scattering analysis. In vitro Cytotoxicity of DOX and Cro loaded PLGA NPs (PLGA-DOX-Cro) on MCF-7 cell line was evaluated using MTT test. Flow cytometry experiments were implemented to distinguish cells undergoing apoptosis from those undergoing necrosis. Furthermore the expression of caspase 3 was examined by western blot analysis.
Results: The prepared formulations had size of 150- 300 nm. Furthermore, PLGA-DOX-Cro nanoparticles inhibited MCF-7 tumor cells growth more efficiently than either DOX or Cro alone at the same concentrations, as quantified by MTT assay and flow cytometry. Studies on cellular uptake of DOX-Cro-NPs demonstrated that NPs were effectively taken up by MCF-7 tumor cells.
Conclusion: This study suggested that DOX-Cro-NPs may have promising applications in breast cancer therapy.- انتشار مقاله: 28-09-1394
- نویسندگان: F. A Langroodi,Z. Hafezi Ghahestani,M. Alibolandi,M. Ebrahimian,M. Hashemi
- مشاهده
- جایگاه : پژوهشی
- مجله: Progress in Color, Colorants and Coatings
- نوع مقاله: Journal Article
- کلمات کلیدی: Mechanical properties,Curing,UV curable formulations,Pigmented coatings,Reactive diluents,Epoxy acrylate
- چکیده:
- چکیده انگلیسی: The formulations contained different acrylate monomer with different structure and functionalities and TiO2, were applied to obtain pigmented acrylic films by UV exposure. The conversion and mechanical characteristic were correlated. The results showed that there is a significant interaction between pigment, reactive diluents’ type and mechanical properties of coatings. It seems that cured films containing Isobornyl acrylate IBOA are claimed to have good flexibility, even though to obtain higher hardness and Tg, higher functionality such as dipentaerythritol pentaacrylate DIPEPA and dipentaerythritol hexaacrylate DPHAis needed. The Tg of the acrylate formulations increased with increasing functionality of monomer and the similar trends can be adopted for the hardness.
- انتشار مقاله: 03-02-1392
- نویسندگان: P. Kardar,M. Ebrahimi,S. Bastani
- مشاهده
- جایگاه : پژوهشی
- مجله: SCIENTIA IRANICA
- نوع مقاله: Journal Article
- کلمات کلیدی:
- چکیده:
- چکیده انگلیسی: In this paper, a low complexity iterative multi-user receiver for the coded MC-FH-CDMA system, is considered, which has been introduced in [1]. The structure of the proposed receiver consists of a Multi-User Likelihood Calculator (MULC) and a bank of SISO channel decoders, one for each active user. Based on the received signal and a priori information about code bits, provided by SISO decoders in the previous iteration, MULC computes the extrinsic information of the coded symbols of active users in the form of a Log-Likelihood Ratio (LLR). This information is used by channel decoders as a priori information to compute an update of LLRs. The processing proceeds in an iterative manner, similar to the decoding of turbo codes. The performance of the proposed receiver is evaluated in AWGN channels. The numerical results show that the new receiver significantly improves system performance, compared to the conventional single user receiver.
- انتشار مقاله: 24-04-1385
- نویسندگان: M. Ebrahimi T.M.,M. Ebrahimi T.M.,M. Ebrahimi T.M.
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Stress Analysis
- نوع مقاله: Journal Article
- کلمات کلیدی: Genetic Algorithm,Finite element,Pressure vessel,Flat end cap,Kuhn-Tucker
- چکیده:
- چکیده انگلیسی: An efficient design is a key factor in final expenditure of a certain construction. Pressure vessels are structures that play an indispensable role in different industries such as petroleum, power plants etc. Pressure vessels are receptacles often used to keep gases or liquids at a pressure typically different from what atmospheric pressure is. End caps which close the end of vessels can be formed in different shapes. Thus, end cap design also has a significant role in the integrity of vessels to prevent fatal accidents that are frequent in the pressure vessel’s history. In this study, an extensive investigation of huge-flat end caps under external pressure was carried out to extract the most efficient geometrical layout. This kind of flat end cap is an essential part of the designed main duct in the Air Cooled Condenser (ACC) systems as a configuration that renders steam to condensed water inside a definite arrangement of finned tubes in a hybrid thermal power plant. To determine an optimized state of stresses considering weight limitation, a number of finite element models were simulated. The simulations were performed in a relatively wide domain of two geometrical variables, namely thickness and height of stiffeners. By constituting a comprehensive data library, an objective function was formed using the results of finite element. The procedure was followed through a genetic algorithm to find an optimized stress state. An analytical study was also accomplished to reach an optimized end cap resulting in the lowest stress level. The findings showed very similar results for the two methods. Furthermore, a profound observation of the influence of two geometrical parameters was conducted in different weight limits. Although this study is based on a particular actual-industrial problem in an implemented power plant, the proposed method and results are applicable to a great number of similar cases.
- انتشار مقاله: 19-03-1398
- نویسندگان: A.R. Hosseinzadeh,M. Ebrahimi,H. Sodagari,A.R. Abedian
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Nanostructures
- نوع مقاله: Journal Article
- کلمات کلیدی: nanoparticle,magnetic,zinc ferrite,Coprecipitation- Superparamagnetic
- چکیده:
- چکیده انگلیسی: Superparamagnetic single phase zinc ferrite nanoparticles have been prepared by coprecipitation method at 20 °C without any subsequent calcination. The composition, crystallite size, microstructure and magnetic properties of the prepared nanoparticles were investigated using X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), Fourier transmission infrared spectrum (FTIR) and vibrating sample magnetometer (VSM). The XRD pattern proved that the nanoparticles were single phase cubic spinel ZnFe2O4 with crystallite size of 5nm. The magnetic measurement showed that the as-prepared nanoparticles of zinc ferrite were superparamagnet at room temperature.
- انتشار مقاله: 24-02-1393
- نویسندگان: R. Raeisi Shahraki,M. Ebrahimi
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Mining and Environment
- نوع مقاله: Journal Article
- کلمات کلیدی: Iran,saltwater,Saturated Zone,Electrical Resistivity Tomography (ERT),Jajrood
- چکیده:
- چکیده انگلیسی: Protection of water resources from contamination and detection of the contaminants and their treatments are among the essential issues in the management of water resources. In this work, the time-lapse electrical resistivity tomography (ERT) surveys were conducted along 7 longitudinal lines in the downstream of the Latian dam in Jajrood (Iran), in order to detect the contamination resulting from the direct injection of a saltwater solution in to the saturated zone in the area. To investigate the pollutant quantities affecting the resistivity of this zone, the temperature and electrical conductivity measurement were carried out using a self-recording device during 20 days (before and after the injection). The results obtained from the self-recording device measurements and ERT surveys indicated that in addition to the salt concentration changes in water, the resistivity changes in the saturated zone were dependent on other factors such as the lithology and absorption of contaminants by the subsurface layers. Furthermore, the expansion of contamination toward the geological trend, sedimentation, and groundwater flow direction of the area were shown.
- انتشار مقاله: 10-03-1394
- نویسندگان: S. Moghaddam,S. Dezhpasand,A. Kamkar Rohani,S. Parnow,M. Ebrahimi
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Mining and Environment
- نوع مقاله: Journal Article
- کلمات کلیدی: Maingate Roadway,Excavation Damaged Zone (EDZ),Longwall Working,Caving Zone (CZ),New Geometrical Model
- چکیده:
- چکیده انگلیسی: In advance longwall mining, the safety of mine network, production rate, and consequently, economic conditions of a mine are dependent on the stability conditions of gate roadways. The gate roadway stability is a function of two important factors: 1) characteristics of the excavation damaged zone (EDZ) above the gate roadway and 2) loading effect due to the caving zone (CZ) above the longwall working, which can extend the EDZ size. Generally, due to the coal seam dip, the failure possibility of main gate roadway is more severe than tail gate roadway. The aim of this work is to determine the longwall working effect on the EDZ extension above main gate roadway. To achieve this purpose, considering three factors involved in the CZ characteristics, the coal seam properties (dip and thickness) and the geomechanical properties of hangingwall, a new geometrical model is developed. Then, based on the geometrical calculations, a new relationship is presented to determine the working influence coeffiecint. Furthermore, taking into account the new geometrical model, an algorithm is suggested for the stability analysis of main gate roadways. Validation of the new geometrical model is carried out by the instrumentation and monitoring results of a longwall working carried out in the Parvade-2 coal mine of Tabas, Tabas, Iran. The results obtained show that there is a good agreement between the values obtained by the new model and the actual measured values. Finally, a sensitivity analysis is carried out on the effects of pillar width, bearing capacity of support system, and coal seam dip.
- انتشار مقاله: 25-06-1393
- نویسندگان: H. Mohammadi,M. A. Ebrahimi Farsangi,H. Jalalifar,A. R. Ahmadi,A. Javaheri
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Mining and Environment
- نوع مقاله: Journal Article
- کلمات کلیدی: Vibration Simulation,Linear Superposition Method,Peak particle velocity (PPV),Sar-Cheshmeh Copper Mine
- چکیده:
- چکیده انگلیسی: A linear superposition method was used for modeling the time history of the production blast vibrations and optimizing the blast sequence to reduce vibration levels in Sar-Cheshmeh copper mine, Kerman, Iran. A single-hole blast for modeling and two double-hole blasts with time delays of 25 and 65 ms between two holes for modeling validation were carried out. The generated vibrations were measured at seven points with different distances and directions around the blasts. These records contain information about the complex mechanism of seismic energy radiation from an explosive source as well as the filtering effect of the signal travel path. Totally, 40 seismograms were synthesized (3 components for each point) for two blasts using the linear superposition method. The results obtained presented a good correlation between the synthetic and measured seismograms. Also, a comparison was made between the measured peak particle velocities (PPVs) and those obtained from the scaled-distance method and linear superposition modeling. This shows the merits of linear superposition modeling to predict PPVs. Moreover, the recorded seismograms of the single-hole blast were used to simulate the vibrations produced by a production blast at seven points. Furthermore, by using a systematic variation of firing delay in the modeling procedure, the effect of delay on the production blast vibrations was studied. The production blast simulations showed that for Sar-Cheshmeh copper mine, the blasts carried out with the inter-row delays more than 40 ms can significantly reduce vibration levels.
- انتشار مقاله: 12-03-1392
- نویسندگان: H. Mansouri,M. A. Ebrahimi Farsangi
- مشاهده