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کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Journal of Sciences, Islamic Republic of Iran
- نوع مقاله: Journal Article
- کلمات کلیدی: ASTER,Hydrothermal alteration,Jabal-Barez,Porphyry Cu deposit,MTMF
- چکیده:
- چکیده انگلیسی: The study area is located in Jabal-Barez Ranges, southeastern part of Kerman Copper Belt (KCB), where the porphyry copper mineralization such as Kerver occurs. This article deals with the enhancement of hydrothermal alteration minerals for exploration of porphyry Cu mineralization, and differentiates intense hydrothermal alteration zones from those with low intensity. Shortwave Infrared (SWIR) bands of ASTER data were used for mineral enhancement. The spectra of representative alteration mineral assemblages consisting of sericite + illite, kaolinite + montmorillonite and epidote + chlorite were extracted from SWIR bands of ASTER. The spectra were applied for mineral discrimination using Mixture Tuned Matched Filtering (MTMF) technique. The image processing results were verified using field observation, spectral measurements, thin section and X-ray diffraction studies of the samples. Findings exhibit ASTER capability to discriminate different alteration zones. Findings also significantly show the role of MTMF algorithm as a useful technique for mineral exploration.
- انتشار مقاله: 16-07-1396
- نویسندگان: S. J. Yousefi,H. Ranjbar,S. Alirezaei,S. Dargahi
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Nanostructures
- نوع مقاله: Journal Article
- کلمات کلیدی: Nanoparticles,Nanocomposite,PVA,Flame Retardancy
- چکیده:
- چکیده انگلیسی: Nickel hydroxide nanostructures were synthesized by a hydrothermal reaction. The effect of different precursors and surfactants on the morphology of nickel hydroxide nanostructures was investigated. Nanostructures were characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, scanning electron microscopy and Fourier transform infrared spectroscopy. The influence of Ni(OH)2 nanostructures on the thermal stability and flame retardancy of the poly vinyl alcohol and cellulose acetate matrix was studied using UL-94 analysis. The enhancement of thermal stability and flame retardancy of nanocomposites is due to the endothermic decomposition of Ni(OH)2 and release of water which dilutes combustible gases.
- انتشار مقاله: 15-12-1394
- نویسندگان: S. R. Yousefi,D. Ghanbari,M. Salavati-Niasari
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Mining and Environment
- نوع مقاله: Journal Article
- کلمات کلیدی: Block size determination,Open-pit mines,Fuzzy Delphi AHP,Fuzzy MOORA
- چکیده:
- چکیده انگلیسی: The computer-based 3D modeling of ore bodies is one of the most important steps in the resource estimation, grade determination, and production scheduling of open-pit mines. In the modeling phase, the volume of the orebody model is required to be filled by the blocks and sub-blocks. The determination of Block Size (BS) is important due to the dependence of the geostatistical issues and calculations related to mining capabilities on it. There are some factors effective in the determination of an optimal BS including the metal content, estimation error, recovery percentage, mining ability, safety, and dilution. In this work, an optimal BS is determined using a two-stage approach. In the proposed approach, the Fuzzy Delphi Analytic Hierarchy Process (FDAHP) and Fuzzy Multi-Objective Optimization by Ratio Analysis (FMOORA) methods are used. In the first phase, the weight of each criterion is calculated based on the opinions of the experts using the FDAHP method. In the second phase, the FMOORA method is applied in order to determine a suitable BS for the design and operation of mining considering the extracted weights in the previous phase. The block model of the Sungun copper mine is studied as a case study to evaluate the capability of the proposed approach. The results of implementation of this approach are desirable because of converting the opinions of the experts to fuzzy values, weighing the experts according to the experience and technical knowledge, weighting the criteria by FDAHP, and choosing the optimal option with FMOORA. Furthermore, the 12.5×12.5×12.5 m3 block (A5) is chosen as an appropriate BS, which is compatible with the real conditions of the studied mine.
- انتشار مقاله: 23-11-1398
- نویسندگان: J. Abdollahei Sharif,A. Jafarpour,S. Yousefi
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Mining and Environment
- نوع مقاله: Journal Article
- کلمات کلیدی: uncertainty,Grade,Capacity,price,Bimetallic Deposits
- چکیده:
- چکیده انگلیسی: In order to catch up with reality, all the macro-decisions related to long-term mining production planning must be made simultaneously and under uncertain conditions of determinant parameters. By taking advantage of the chance-constrained programming, this paper presents a stochastic model to create an optimal strategy for producing bimetallic deposit open-pit mines under certain and uncertain conditions. The uncertainties of grade, price per product, and capacities of the various stages in the process of production of the final product were considered. The results of solving the deterministic and stochastic models showed that the stochastic model had a greater compatibility and performance than the other ones.
- انتشار مقاله: 06-10-1395
- نویسندگان: E. Bakhtavar,A. Jafarpour,S. Yousefi
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Electrical and Computer Engineering Innovations (JECEI)
- نوع مقاله: Journal Article
- کلمات کلیدی: Soft Error,Low Power Design,Hardened Flip-flop,Dual Inter locked Storage Cell,Level Converting Technique
- چکیده:
- چکیده انگلیسی: Low scaling technology makes a significant reduction in dimension and supply voltage, and lead to new challenges about power consumption such as increasing nodes sensitivity over radiation-induced soft errors in VLSI circuits. In this area, different design methods have been proposed to low power flip-flops and various research studies have been done to reach a suitable hardened flip-flops. In this paper we combined these two generally separate addressed issues to reach a new low power high reliability flip-flop (LP-HRFF). LP-HRFF operates over 1GHz clock frequency and structured based on an appropriate combination of dual interlocked storage cell, level converting techniques and clock signal controlled gates. The extensive simulations exhibit LP-HRFF has 0% single event upset rate against single transient events occurred on inputs and internal nodes and show the improvement of power consumption up to 42.8% and power delay product up to 24.6% when compared with its counterparts. Furthermore, the simulation results approve the robustness and efficiency of the proposed flip-flop against process variations.
- انتشار مقاله: 20-11-1395
- نویسندگان: S. Yousefian Langroudi,R. Niaraki Asli
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Chemical Health Risks
- نوع مقاله: Journal Article
- کلمات کلیدی: Preconcentration,FAAS,Determination of lead,Graphene oxide with covalently linked N-methyl-glycine and 3,4- dihydroxybenzaldehyde (graphene-f-OH)
- چکیده:
- چکیده انگلیسی: A novel, simple, sensitive and effective method has been developed for preconcentration of lead. This solid-phase extraction adsorbent was synthesized by functionalization of graphenes with covalently linked N-methyl-glycine and 3, 4-dihydroxybenzaldehyde onto the surfaces of graphite. The method is based on selective chelation of Pb (II) on surfactant coated C18, modified with functionalization of graphenes (graphene-f-OH). The adsorbed ions were then eluted with 4 ml of 4 M nitric acid and determined by flame atomic absorption spectrometry (FAAS) at 283.3 for Pb. The influence of flow rates of sample and eluent solutions, pH, breakthrough volume, effect of foreign ions were investigated on chelation and recovery. 1.5 g of surfactant coated C18 adsorbs 40 mg of the functionalization of graphenes (graphene-f-OH) base which in turn can retain15.2±0.8mg of each of the two ions. The limit of detection (3σ) for Pb(II) was found to be 3.20 ng l -1. The enrichment factor for both ions is 100. The mentioned method was successfully applied on the determination of Pb in different water samples.
- انتشار مقاله: 16-09-1392
- نویسندگان: A. Moghimi,S. Yousefi Siahkalrodi
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Chemical Health Risks
- نوع مقاله: Journal Article
- کلمات کلیدی: Hydrogen peroxide,Fenton reaction,Oil Contamination,Refining
- چکیده:
- چکیده انگلیسی: Refining oil-contaminated soils has a great importance especially in oil producer countries such as Iran. Different methods have been provided to eliminate oil contaminations from soil. The aim of this study was to investigate the effect of Hydrogen peroxide concentration in refining oil-contaminated soils with Fenton chemical method. To do this, a calcareous soil complex sample was collected around the Tehran oil refinery and treated with 10 and 20 percent petroleum in three replications. After reaching to balance conditions, the sample was treated using0.01, 0.02,0.12,0.24,0.47 and 0.71 equivalent of Hydrogen peroxide. The results indicated that in all level of H2O2, the eliminating efficiency in 10 percent was more than 20 percent treatment. Also a significant difference between the levels of hydrogen peroxide used in the removal of oil pollution in both surface concentrations was obtained (P<0.01).
- انتشار مقاله: 07-03-1392
- نویسندگان: A. S. Yousefi,A. Bostani
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Medical Sciences
- نوع مقاله: Journal Article
- کلمات کلیدی:
- چکیده:
- چکیده انگلیسی: Background: The ratio of urine protein to urine osmolality has recently been suggested as an accurate method to determine proteinuria. Objective: We studied the correlation of urine protein to urine osmolality ratio with 24-hr urinary protein excretion. Methods: 150 children aged 0.11–17 years admitted to the Department of Pediatric Nephrology were included in this study. Early morning urine samples and 24-hr urine specimens were collected and analyzed for protein, creatinine, and osmolality. The patients with chronic renal failure were not excluded. Two groups were established: Children with no proteinuria (group 1) and those with proteinuria (group 2). Results: The optimal cutoff value of abnormal proteinuria and nephrotic range proteinuria was determined to be a protein–osmolality ratio (Up/Uosm) 0.27 and 1.59 mg/l/mOsm respectively. The correlation of 24-hr urinary protein excretion with both urinary protein/creatinine ratio (Up/Ucr) and Up/Uosm was highly significant (p<0.001). According to the receiver operator characteristic (ROC) curves analysis, we found no differences between Up/Uosm and Up/Ucr ratios in detecting either abnormal proteinuria or nephrotic syndrome. Conclusion: Urine protein to urine osmolality ratio seems to be a simple and a valuable test for the assessment of the degree of proteinuria in children.
- انتشار مقاله: 07-07-1394
- نویسندگان: N. Hooman,H. Otoukesh,H. Safaii,M. Mehrazma,S. Yousefi
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Engineering, Transactions A: Basics
- نوع مقاله: Journal Article
- کلمات کلیدی: Reluctance Motors,electric motors,Electric Machines,Disc,Type Motors,Type Reluctance Motors
- چکیده:
- چکیده انگلیسی: This paper explores the theory and potential of a family of reluctance motors as well as brief review of different types of reluctance motors, motivated by the increased demands for geometric versatility and ruggedness for electric motors. This paper presents a new and novel disc type reluctance motor that has been designed built, tested, and analyzed. The magnetic circuit-based analysis shows an obtainable torque per volume 5 KNm/m3 for the motor which is comparable with other types of electric motors.
- انتشار مقاله: 11-10-1348
- نویسندگان: S. Yousefi Azad,E. Afjei
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Industrial Mathematics
- نوع مقاله: Journal Article
- کلمات کلیدی: Matrix differential equation,Bernstein multi-scaling polynomials,Operational matrix of integration.
- چکیده: .
- چکیده انگلیسی: In The current paper presents an idea for solving a class of linear matrix differential equations of second order. To perform so, the operational matrix of the integration based on the Bernstein multi-scaling polynomials are used to reduce the main problem to system of matrix equations. Numerical experiments illustrate the applicably and efficiency of the propounded technique.
- انتشار مقاله: 08-07-1397
- نویسندگان: M. Mohamadi,E. Babolian,S. A. Yousefi
- مشاهده