در هنگام جستجو کلمه در قسمت عنوان میتوانید کلمات مورد جستجو را با کاراکتر (-) جدا کنید.
کاربرد نوع شرط:
- جایگاه : پژوهشی
- مجله: Iranian Journal of Optimization
- نوع مقاله: Journal Article
- کلمات کلیدی: Homotopy Perturbation Method,Adomian Decomposition Method,Partial differential equation,Homotopy Analysis Method,KLEIN-GORDON
- چکیده:
- چکیده انگلیسی: In this paper, nonlinear Klein-Gordon equation with quadratic term is solved by means of an analytic technique, namely the Homotopy analysis method (HAM).
Comparisons are made between the Adomian decomposition method (ADM), the exact solution and homotopy analysis method. The results reveal that the proposed method is very effective and simple.- انتشار مقاله: 18-01-1388
- نویسندگان: H. Jafari,M. Saeidy,M. Arab Firoozjaee
- مشاهده
- جایگاه : پژوهشی
- مجله: The ISC International Journal of Information Security
- نوع مقاله: Journal Article
- کلمات کلیدی: Mandatory Access Control,Multilevel Security,Authorization,Context Awareness,Information Flow Control
- چکیده:
- چکیده انگلیسی: Mandatory access control models have traditionally been employed as a robust security mechanism in multilevel security environments such as military domains. In traditional mandatory models, the security classes associated with entities are context-insensitive. However, context-sensitivity of security classes and flexibility of access control mechanisms may be required especially in pervasive computing environments. To this aim, we propose a context-aware mandatory access control model (CAMAC) capable of dynamic adaptation of access control policies to context, and of handling context-sensitive class association, in addition to preservation of confidentiality and integrity as specified in traditional mandatory access control models. In order to prevent any ambiguity, a formal specification of the model and its elements such as context predicates, context types, level update rules, and operations is required. High expressiveness of the model allows specification of the traditional mandatory access control models such as BLP, Biba, Dion, and Chinese Wall. The model can also be considered as an information flow control model with context-sensitive association of security classes.
- انتشار مقاله: 07-02-1387
- نویسندگان: J. H. Jafarian,M. Amini
- مشاهده
- جایگاه : پژوهشی
- مجله: Progress in Color, Colorants and Coatings
- نوع مقاله: Journal Article
- کلمات کلیدی: Graphene Oxide,EIS,Corrosion resistance,Epoxy nanocomposite,poly(amidoamine) dendrimer
- چکیده:
- چکیده انگلیسی: In this research, graphene oxide (GO) nanoparticles were modified by second and fourth generations of poly(amidoamine) dendrimers in order to improve the particle dispersion quality in the epoxy matrix and therefore its barrier anti-corrosion performance. Confirmation on the GO surface modification by Polyamidoamine generation 2 (PAMAM2) and polyamidoamin generation 4 (PAMAM4) was carried out by Fourier transforms infrared (FT-IR) spectroscopy and thermogravimetric analysis (TGA). The corrosion protection properties of the epoxy composites against corrosive electrolyte (3.5 wt.% NaCl solution) was investigated by salt spray and electrochemical methods. The dispersion of unmodified and modified GO sheets in the epoxy matrix was studied by FE-SEM analysis. The FT-IR test results evidenced that the GO sheets were successfully modified with PAMAM 2 and 4 via the covalent binding mechanism. Salt spray and EIS test results revealed that the epoxy composites loaded with GO-PAMAM4 and PAMAM4 showed the highest improvement in the corrosion resistance. FE-SEM images from the fracture surface of the coatings revealed that the dispersion of GO sheets within the epoxy coating was improved after modification by PAMAM4.
- انتشار مقاله: 02-06-1398
- نویسندگان: M. Maadani,H. Jafari,M. R. Saeb,B. Ramezanzadeh,F. Najafi,D. Puglia
- مشاهده
- جایگاه : پژوهشی
- مجله: Progress in Color, Colorants and Coatings
- نوع مقاله: Journal Article
- کلمات کلیدی: TiO2,Nanoparticles,SEM,Al2O3,ZnO,Camouflage
- چکیده:
- چکیده انگلیسی: Drawing upon reflectance behavior of woodland colors involving dark brown in the UV-Vis-IR bands, two colored pigments were used to print cotton/polyester Co/PET goods. Inorganic nanoparticles of TiO2, ZnO and AL2O3 were also loaded onto the printing formulation. The reflectance profile of treated samples was studied using Jasco V-670 reflectance spectrophotometer. SEM analysis of printed fabrics and the effect of increasing inorganic nanoparticles on rubbing, light and washing fastness with colorimetric values of printed samples as well as the result of nanoparticles on wettability and air permeability of printed samples were investigated. Adjusting the reflectance profile of dark brown color was successfully applied using colored pigments along with the nanoparticles. The results indicate that the presence of TiO2 and ZnO nanoparticles in load limit of 0.25-1 g/kg in printing pastes made significant changes in the behavior of IR band though only a slight change in visible reflectance of printed fabrics was found. The samples containing nanoparticles showed great fastness levels in washing, rubbing and light fastness experiments and a considerable increase in wettability of printed fabrics. Furthermore, air permeability of printed fabrics containing nanoparticles was found superior to samples printed free of nanoparticles.
- انتشار مقاله: 11-10-1348
- نویسندگان: H. Jafari,M. Khajeh Mehrizi,S. Fattahi
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of Mining and Environment
- نوع مقاله: Journal Article
- کلمات کلیدی: D2EHPA,Solvent extraction and stripping,chloride solution,Zn-Mn-Cd ions,McCabe-Thiele Diagram
- چکیده:
- چکیده انگلیسی: In this research work, solvent extraction and stripping of zinc ions from a Zn-Mn-Cd-bearing solution was investigated using D2EHPA as the extractant in a chloride medium. The efficiency of the extraction and stripping stages was evaluated separately, and different parameters such as the pH, extractant concentration, reaction temperature, and contact time were studied. Based on the results obtained, 97% of zinc, 14% of manganese, and 3% of cadmium were extracted at pH = 2.5, 10% (v/v) of D2EHPA, and 40 °C from the solution containing 5 g L-1 of each metal ion. The stripping isotherms of zinc, manganese, and cadmium at different pH values showed that manganese and zinc were stripped at two different pH values. Thus more than 70% of manganese and more than 90% of zinc were stripped at pH = 2.5 and pH = 0.5, respectively. Kinetic studies indicated that the extraction and stripping of zinc in the first 0.5-1 minute was high. The McCabe–Thiele diagrams showed that two stages of extraction and two stages of stripping in the continuous counter-current flow condition were adequate to separate zinc from Mn and Cd. The dominant Zn species extracted by D2EHPA was ZnCl+, and the values for the thermodynamic parameters ΔHo, ΔSo, and ΔGo were 25.65 kJ mol−1, 79.20 J K−1 mol−1, and 0.86 kJ mol−1, respectively, which showed that the reaction was endothermic at equilibrium.
- انتشار مقاله: 26-04-1398
- نویسندگان: H. Jafari,H. Abdollahi,M. Gharabaghi,A.A. Balesini
- مشاهده
- جایگاه : پژوهشی
- مجله: Journal of AI and Data Mining
- نوع مقاله: Journal Article
- کلمات کلیدی: Artificial Neural Network,modeling,Energy,Food Industry
- چکیده:
- چکیده انگلیسی: In this study, the energy consumption in the food and beverage industries of Iran was investigated. The energy consumption in this sector was modeled using artificial neural network (ANN), response surface methodology (RSM) and genetic algorithm (GA). First, the input data to the model were calculated according to the statistical source, balance-sheets and the method proposed in this paper. It can be seen that diesel and liquefied petroleum gas have respectively the highest and lowest shares of energy consumption compared with the other types of carriers. For each of the evaluated energy carriers (diesel, kerosene, fuel oil, natural gas, electricity, liquefied petroleum gas and gasoline), the best fitting model was selected after taking the average of runs of the developed models. At last, the developed models, representing the energy consumption of food and beverage industries by each energy carrier, were put into a finalized model using Simulink toolbox of Matlab software. Results of data analysis indicated that consumption of natural gas is being increased in Iran food and beverage industries, while in the case of fuel oil and liquefied petroleum gas a decreasing trend was estimated.
- انتشار مقاله: 26-12-1394
- نویسندگان: B. Hosseinzadeh Samani,H. HouriJafari,H. Zareiforoush
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Veterinary Research
- نوع مقاله: Journal Article
- کلمات کلیدی: Silver carp,Rotifer,B. licheniformis,B. latrospores
- چکیده: در این مطالعه تاثیر اسپورهای پروبیوتیکی Bacillus laterosporus) و (Bacillus licheniformis بر نرخ رشد و بقاء لارو ماهی کپور نقرهای (Hypophthalmichthys molitrix) مورد ارزیابی قرار گرفت. روتیفر دریایی Brachionus plicatilis به عنوان غذای زنده جهت انتقال پروبیوتیکها در نظر گرفته شد. در قدم اول روتیفر در آب دریا با شوری 15 گرم در لیتر مورد پرورش قرار گرفت و در طول دوره پرورش از ریز-جلبک دریایی Nannochloropsis oculata تغذیه گردید. لارو ماهی کپور نقرهای از مرکز تکثیر و پرورش ماهیان گرمابی تهیه گردید (گلستان، ایران) و در پنج تیمار با 3 تکرار (4 تیمار آزمایشی و یک تیمار شاهد) تقسیم شد. روتیفرها از تانکهای پرورش متراکم، با تراکم 200 روتیفر در میلیلیتر فیلتر گردیده و جهت فرآیند غنی سازی به ظروف مخروطی منتقل شدند و به مدت 24 ساعت تحت شرایط غنی سازی قرار گرفتند. دو حالت از غنی سازی در نظر گرفته شد: غنی سازی روتیفرها و غنی سازی آب محیط پرورش. تیمارهای T1 و T2 از روتیفر غنی سازی شده با پروبیوتیک تغذیه میشدند این در حالی بود که تیمارهای T3 و T4 از روتیفرهای غیر غنی سازی شده استفاده مینمودند، در عوض غلظت برابر با غلظت استفاده شده جهت غنی سازی به محیط پرورش لاروها افزوده میشد. در انتهای مطالعه (2/1 ± 4/4) T3 و (95/1 ± 05/5) T4 که غلظت مشابه پروبیوتیک مصرفی جهت غنی سازی، مستقیما به محیط پرورش آنها افزوده میشد، نرخ رشد معنیداری را نسبت به T1 و T2 نشان دادند (P<0.05). در تیمارهای (03/1 ± 9/3) T1 و (36/0 ± 3/3) T2 نیز اختلاف معنیداری از جهت نرخ رشد با تیمار شاهد (94/0 ± 21/2) وجود داشت (P<0.05).
- چکیده انگلیسی: This study was carried out to evaluate the effect of probiotic (Bacillus latrospores and Bacillus licheniformis) on growth and survival of Silver carp larvae (Hypophthalmichthys molitrix). Rotifers (Brachionus plicatilis) were used as live prey vehicle for probiotic transport. They were cultured in sea water with 15 ppt salinity and Nannochloropsis oculata microalgae was used as feed. Five treatments were prepared with three replicates (four experimental treatments and one control). Silver carp larvae were obtained from a local fish farm (Golestan, Iran). Rotifers were filtered from intensive cultivation tanks with 200 rotifer/ml density and then transferred to conical glasses for the enrichment process, and were kept under enrichment conditions for 24 h. Two forms of enrichment were carried out: rotifer biocapsulation and rearing water enrichment. T1 and T2 were fed with biocapsulated rotifers and T3 and T4 were fed non-biocapsulated rotifers. Instead of biocapsulation, the same density of bacteria was injected directly into the rearing water of T3 and T4. T3 (4.4 ± 1.2 mg) and T4 (5.05 ± 1.95 mg) treatments of probiotic injected water had significantly higher growth rates than T1 (2.21 ± 0.94 mg) and T2 (3.9 ± 0.36 mg), (P<0.05). T1 (3.9 ± 1.03 mg) and T2
(3.3 ± 0.36 mg) had higher growth rates than the control (2.21 ± 0.94 mg) and were also significantly
different from each other (P<0.05).- انتشار مقاله: 12-10-1390
- نویسندگان: J. Sahandi,H. Jafariyan,R. Roozbehfar,S. Babaei,M. Dehestani
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Nanoscience and Nanotechnology
- نوع مقاله: Journal Article
- کلمات کلیدی: Multi-Walled Carbon Nanotubes,Bi-functional mechanism,Fuel cells,Methanol electrooxidation
- چکیده:
- چکیده انگلیسی: In the present study, PtRuCe/MWNTs nanocatalysts synthesized via polyol process technique are applied as anode electro-catalyst in methanol electro-oxidation reaction (MOR). To characterize the nanocatalysts, TEM, XRD, EDS and XPS are investigated. Cyclic voltammetry and choronoamperometry are used to evaluate the electro-catalytic activity and stability of the catalysts in methanol electro-oxidation, respectively. Further addition of the Ce promoter to MWNTs-supported PtRu nanocatalyst shows the highest activity and the lowest onset potential in MOR at Ce to Pt molar ratio of 0.7. A significant enhancement of the forward anodic peak in cyclic voltammetry experiments is observed for the Ce-promoted PtRu catalyst with cerium to platinum molar ratio of 0.7, i.e. 349 mA/cm2.mgPt , in comparison with 182 mA/cm2.mgPt and 251 mA/cm2.mgPt , respectively, corresponding to Pt/MWNTs and PtRu(1:1)/MWNTs nanocatalysts. Furthermore, the chronoamperommetry results present a remarkable improvement in the final current density of PtRuCe/MWNTs (6.1 mA/cm2), compared to the un-promoted catalysts, having a decreasing propensity, i.e. PtRu/MWNTs (3.7 mA/cm2) and Pt/MWNTs (2.05 mA/cm2.mgcat). The improved performance of PtRuCe/MWNTs may be attributed to the formation of highly-dispersed Pt nanoparticles on the support, followed by a significant enhancement of bifunctional mechanism, as a result of cerium incorporation.
- انتشار مقاله: 28-04-1392
- نویسندگان: E. Esmaeili,A. M. Rashidi,Kh. Jafari-Jozani
- مشاهده
- جایگاه : پژوهشی
- مجله: International Journal of Engineering, Transactions A: Basics
- نوع مقاله: Journal Article
- کلمات کلیدی: Corrosion inhibitor,Potentiodynamic polarization,CO2 corrosion,Linear Polarization Resistance,Lungmuir Adsorption Isotherm
- چکیده:
- چکیده انگلیسی: The performance of an Imidazoline based commercial corrosion inhibitor on CO2 corrosion of mild steel was investigated in a Cl- containing solution employing linear polarization resistance (LPR), potentiodynamic polarization and monitoring corrosion potential techniques. Experimental results showed that an increase of the commercial inhibitor concentration up to 500 ppm increases the RP value and produces an efficiency of 90 percent. The increase of a test solution temperature at 60°C caused an increase on RP value compared to RP measured at room temperature this suggests adsorption of the inhibitor is promoted by temperature. Plot of c/θ versus inhibitor concentration (c) using different methods showed a straight line with a slope very close to unity, indicating that adsorption of the investigated commercial inhibitor on steel/saturated CO2 solution obeys the Lungmuir adsorption isotherm.
- انتشار مقاله: 11-10-1348
- نویسندگان: Mohammad Hadi Moayed,A.H. Jafari,A. Khavasfar
- مشاهده
- جایگاه : پژوهشی
- مجله: Iranian Journal of Optimization
- نوع مقاله: Journal Article
- کلمات کلیدی: Homotopy Perturbation Method,Adomian Decomposition Method,Partial differential equation,Homotopy Analysis Method,KLEIN-GORDON
- چکیده:
- چکیده انگلیسی: In this paper, nonlinear Klein-Gordon equation with quadratic term is solved by means of an analytic technique, namely the Homotopy analysis method (HAM).
Comparisons are made between the Adomian decomposition method (ADM), the exact solution and homotopy analysis method. The results reveal that the proposed method is very effective and simple.- انتشار مقاله: 18-01-1388
- نویسندگان: H. Jafari,M. Saeidy,M. Arab Firoozjaee
- مشاهده