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  • دکتری (1387)

    مهندسی مکانیک بیوسیستم

    دانشگاه تربیت مدرس، تهران، ایران

  • کارشناسی‌ارشد (1383)

    مهندسی مکانیک بیوسیستم

    دانشگاه تربیت مدرس، تهران، ایران

  • کارشناسی (1381)

    مهندسی مکانیک بیوسیستم

    دانشگاه ارومیه، ارومیه، ایران

  • طراحی ماشین و روش اجزای محدود
  • انرژیهای تجدید پذیر
  • موتورهای درونسوز-سوخت و احتراق
  • روشهای شبیه سازی- مدلسازی و بهینه سازی

    دکتر غلامحسن نجفی دوره کارشناسی خود را در دانشگاه ارومیه در بازه زمانی 1377 لغایت 1381 در رشته مهندسی مکانیک بیوسیستم گذرانده و در سال 1381 با رتبه اول در مقطع کارشناسی ارشد وارد دانشگاه تربیت مدرس شد و در سال 1383 در رشته مهندسی مکانیک بیوسیستم فارغ التحصیل گردید. سپس با کسب رتبه اول در سال 1383 وارد مقطع دکتری دانشگاه تربیت مدرس در گروه مهندسی مکانیک بیوسیستم شده و در سال 1387 با درجه عالی از رساله خود دفاع نموده و فارغ التحصیل گردید. ایشان یک دوره پسا دکتری نیز به طور همزمان در دانشگاههای UMP مالزی و USQ استرالیا گذرانده و از سال 1388 به عنوان عضو هیات علمی گروه مهندسی مکانیک بیوسیستم دانشکده کشاورزی دانشگاه تربیت مدرس مشغول به تحقیق و تدریس می باشند.

    ارتباط

    رزومه

    Detection and classification of mechanical faults of an engine alternator based on vibration signals and frequency analysis

    Ashkan Moosavian, Meghdad Khazaee, Mohammad Reza Asadi Asad Abad, Gholamhassan Najafi
    Journal PapersThe Journal of Engine Research , Volume 61 , Issue 61, 2021 February 10, {Pages 10-Mar }

    Abstract

    In this article, an intelligent system is introduced in order to detection and classification of some common mechanical faults of an engine alternator based on the frequency analysis of vibration signals. For this purpose, firstly the vibration signals of an alternator under four conditions, including healthy, bearing corrosion, cracked rotor and unbalanced excited shaft, were captured by an accelerometer. Time-domain signals were then transformed into frequency-domain with the aid of FFT. At the next step, power spectral density (PSD) method was used for the secondary frequency signal processing level. Afterward, in data mining step, twelve statistical features were extracted from the PSD values of the signals, which were fed as the input

    Investigation on the Fouling and Heat Transfer Characteristics of Novel EGR Cooler (Semi-spiral) for Diesel Engine Fueled with Biodiesel

    F Jamali, B Ghobadian, G Najafi, Bo Zhang, XX Jiang
    Journal PapersIOP Conference Series: Materials Science and Engineering , Volume 1062 , Issue 1, 2021 February 1, {Pages 012024 }

    Abstract

    In this study, heat transfer characteristic and fouling of Novel EGR cooler (Semi-spiral) system were investigated. In this study, waste vegetable oil (Waste Cooking Oil) was used as feedstock for biodiesel production. The experiment was conducted in different loads (25%, 50% and 75%) and different speeds (2100rpm and 2400rpm). Four fuel blends were prepared and used (B0, B5, B10, and B15). The new EGR cooler has 6 tubes in length of 19 cm and overall heat transfer coefficient of 35.63 W/m^ 2 K which is acceptable with compared to overall heat transfer coefficient of shell and tube heat exchanger. Also, the total resistance of fouling (Rft) derived was 0.002712 m^ 2 K/W. The maximum heat transfer efficiency is 94% and the minimum heat trans

    Optimization Effect of Ultrasound on Rupture Force and Kernel Extracting Quality of Walnut using Response Surface Method (RSM)

    E Biabani Agdam, MH Khoshtaghaza, Gh Najafi
    Journal PapersJournal of Agricultural Machinery , Volume 11 , Issue 2, 2021 September 23, {Pages 331-342 }

    Abstract

    Introduction One of the most important and sensitive steps after walnut harvesting is the separation of the kernel from its shell. Walnut rupture force is an appropriate criterion for design with high performance and better quality, which can be used as the basis for designing and adjusting the various parts of machines that are in contact with walnut. The lower rupture force caused the less energy requirement to separate the walnut kernel from the shell. The use of ultrasound in ambient fluids is well known to cause turbulence and biological cell rupture. These effects arise principally from the phenomenon known as cavitation which can scour surfaces and damage cellular material. Therefore the object of this study is to find the effect of

    A systematic review on graphene-based nanofluids application in renewable energy systems: Preparation, characterization, and thermophysical properties

    Madderla Sandhya, D Ramasamy, K Sudhakar, K Kadirgama, M Samykano, WSW Harun, G Najafi, M Mofijur, Mohamed Mazlan
    Journal Papers , Volume 44 , 2021 April 1, {Pages 101058 }

    Abstract

    Graphene has attracted much attention from various researchers because of its enhanced mechanical, thermal, and physio-chemical properties. Graphene exhibits high thermal conductivity and stability, less erosion and corrosion than other available nanoparticles. Various existing literature signifies a large portion of the research focuses on stability, heat transfer characteristics and thermal conductivity of Graphene nanofluids. This review article represents a detailed analysis of the preparation techniques, characterization methods stability evaluation, and thermal properties enhancements of Graphene nanofluids. Comparative analysis of the effects of nanoparticle size, volume concentration and temperature on thermal conductivity and visco

    Optimization of Performance and Exhaust Emissions of a Spark-Ignition (SI) Engine Fueled with Bioethanol-Gasoline Blends using TOPSIS Methodology

    I Baratian, Muhammad Yasar, G Najafi, B Ghobadian, Bo Zhang, XX Jiang
    Journal PapersIOP Conference Series: Materials Science and Engineering , Volume 1062 , Issue 1, 2021 February 1, {Pages 012023 }

    Abstract

    Energy crises and environment impact forced governments and countries to develop utilizing renewable energy in different forms. One of the first forms of alternative energy which was in use is bioethanol which is using in SI (spark ignition) engines as pure fuel or after blending with gasoline. The selection of proper blending of bioethanol plays an important role in the production of alternative energy. In this investigation, the use of TOPSIS (Technique for Order Performance by Similarity to Ideal Solution) to select the optimal value of the engine performance and exhaust pollutants which run at various bio-ethanol-gasoline fuel blends, namely E5, E10, E15 and E20. Obtained results indicate that performance parameters (ie torque, power) f

    Assessment of a solar-driven cogeneration system for electricity and desalination

    Alireza Rafiei, Reyhaneh Loni, Gholamhassan Najafi, Shuhaimi B Mahadzir, Evangelos Bellos, Mohsen Sharifpur, Mohamed Mazlan
    Journal PapersJournal of Thermal Analysis and Calorimetry , 2021 February 5, {Pages 21-Jan }

    Abstract

    The goal of the present paper is the investigation of a solar desalination system with an organic Rankine cycle system for power and freshwater production. This system is an environmentally friendly technology that is able to utilize solar energy properly in a novel cogeneration application. A parabolic trough concentrator with a smooth and corrugated receiver was employed as the heat source of the desalination system. A humidifier–dehumidifier desalination technology was used for producing freshwater. The electricity is produced by an organic Rankine cycle which is fed both by the solar field and by the hot brine. The present analysis is performed by using a detailed numerical model which is validated by experimental literature data. Bas

    Graphene Nanoplatelets Suspended in Different Basefluids Based Solar Collector: An Experimental and Analytical Study

    Omer A Alawi, Haslinda Mohamed Kamar, Abdul Rahman Mallah, Hussein A Mohammed, Mohd Aizad Sazrul Sabrudin, Omar A Hussein, Salim Newaz Kazi, Gholamhassan Najafi
    Journal PapersProcesses , Volume 9 , Issue 2, 2021 February , {Pages 302 }

    Abstract

    A flat plate solar collector (FPSC) was analytically studied, with functionalized graphene nanoplatelets (f-GNPs) as its working fluid. Four samples (wt% nanofluids) were prepared in different base fluids such as ethylene glycol (EG), distilled water (DW): EG (70: 30), and DW: EG (50: 50). Experimental results (via DW) were used to verify the effectiveness of the analytical model. Some of the operating conditions were taken into account in this research, including temperatures, power, and mass flow rates. Experimental techniques were used to elucidate the modified nanofluids’ physicochemical properties, such as its particle sizes, stability, and morphology, involving electron microscopes (EMs), UV–VIS, and X-ray techniques. Differential

    Graphene Nanoplatelets Suspended in Different Basefluids Based Solar Collector: An Experimental and Analytical Study. Processes 2021, 9, 302

    OA Alawi, HM Kamar, AR Mallah, HA Mohammed, MAS Sabrudin, OA Hussein, SN Kazi, G Najafi
    Journal Papers , 2021 January , {Pages }

    Abstract

    A flat plate solar collector (FPSC) was analytically studied, with functionalized graphene nanoplatelets (f-GNPs) as its working fluid. Four samples (wt% nanofluids) were prepared in different base fluids such as ethylene glycol (EG), distilled water (DW): EG (70: 30), and DW: EG (50: 50). Experimental results (via DW) were used to verify the effectiveness of the analytical model. Some of the operating conditions were taken into account in this research, including temperatures, power, and mass flow rates. Experimental techniques were used to elucidate the modified nanofluids’ physicochemical properties, such as its particle sizes, stability, and morphology, involving electron microscopes (EMs), UV–VIS, and X-ray techniques. Differential

    Evaluation and Improvement of Thermal Energy of Heat Exchangers with SWCNT, GQD Nanoparticles and PCM (RT82)

    Mohammadreza Hasandust Rostami, Gholamhassan Najafi, Ali Motevalli, Nor Azwadi Che Sidik, Muhammad Arif Harun
    Journal PapersJournal of Advanced Research in Fluid Mechanics and Thermal Sciences , Volume 79 , Issue 1, 2021 January 1, {Pages 153-168 }

    Abstract

    Today, due to the reduction of energy resources in the world and its pollutants, energy storage methods and increase the thermal efficiency of various systems are very important. In this research, the thermal efficiency and energy storage of two heat exchangers have been investigated in series using phase change materials (RT82) and single wall carbon nanotubes (SWCNT) and graphene quantum dot nanoparticles (GQD) In this research, two heat exchangers have been used in combination. The first heat exchanger was in charge of storing thermal energy and the second heat exchanger was in charge of heat exchange. The reason for this is to improve the heat exchange of the main exchanger (shell and tube) by using heat storage in the secondary exchang

    The rotor-stator type hydrodynamic cavitation reactor approach for enhanced biodiesel fuel production

    Bahram Hosseinzdeh Samani, Mehrsa Behruzian, Gholamhassan Najafi, Ebrahim Fayyazi, Barat Ghobadian, Ava Behruzian, M Mofijur, Mohamed Mazlan, Jun Yue
    Journal PapersFuel , Volume 283 , 2021 January , {Pages 118821 }

    Abstract

    Today renewable energies such as biodiesel have considerable role in the bio-based economy. Long production time and low efficiency are a number of problems in biodiesel production that is essential to be considered when designing and operating the biodiesel production systems. In this study, using safflower oil in a hydrodynamic cavity reactor, biodiesel fuel was produced in the possible shortest time and maximum efficiency. The effect of reaction time (30, 60 and 90?s), concentration of potassium hydroxide catalyst (0.75%, 1% and 1.25%), alcohol to oil ratio (6, 8 and 10) and rotor-stator distance (1?cm, 2?cm and 3?cm) on the reaction yield were analyzed. The results were analyzed by response surface methodology. Among the independent var

    Design of an Integrated Photovoltaic Site: Case of Isfahan's Jarghouyeh photovoltaic plant

    Mostafa Esameili Shayan, Gholamhassan Najafi
    Journal PapersJournal of Energy Planning And Policy Research , Volume 6 , Issue 4, 2021 February 10, {Pages 229-250 }

    Abstract

    The use of renewable energy sources distributed throughout power grids, especially in distribution systems, has increased significantly. With the use of solar energy in low-pressure grids and load imbalances, it is important to investigate the solution with the aim of balancing and compensating the load, minimizing the reduction in voltage, and monitoring the electrical disturbance resulting from the voltage profile and the network interaction. In this research, analysis and optimization of the electrical distortion of the local photovoltaic power plant in the weak, unbalanced four-wire low-voltage distribution grid were carried out over a specified time period. Under two scenarios, simulation on the part of Isfahanchr ('39') s Jarghouyeh p

    Investigating the contribution of carbon nanotubes and diesel-biodiesel blends to emission and combustion characteristics of diesel engine

    Raslan A Alenezi, AM Norkhizan, R Mamat, G Najafi, Mohamed Mazlan
    Journal PapersFuel , Volume 285 , 2021 February 1, {Pages 119046 }

    Abstract

    The ultimate purpose of the current research work is to trigger the effect of 50, 100 and 150?ppm multi-walled carbon nanotubes (MWCNTs) in addition to diesel-biodiesel blended fuels with a focus on the emission and combustion characteristics of diesel engine. A single-cylinder diesel engine, with 1800?rpm engine speed and 100% engine load, was used to run the experiments on all fuel blends. The results indicated a significant reduction of the carbon dioxide (CO2) formation as a result of increase in MWCNTs, particularly for B20 and B30 samples. Also, the results emphasized a significant reduction of nitrogen oxides (NOx) formation as fa as B20 and B40 blends were concerned. However, regarding the B10 blends, an increasing trend of NOx emis

    A novel approach for bio-lubricant production from rapeseed oil-based biodiesel using ultrasound irradiation: Multi-objective optimization

    Sara Almasi, Barat Ghobadian, Gholamhassan Najafi, Masoud Dehghani Soufi
    Journal PapersSustainable Energy Technologies and Assessments , Volume 43 , 2021 February 1, {Pages 100960 }

    Abstract

    Due to the damaging environmental impacts resulting from direct entry of mineral lubricants into the environment, the use of bio-lubricants as a sustainable and renewable alternative to mineral lubricants is necessary; therefore, bio-based lubricants play an important role in overcoming existing challenges and reducing energy consumption. The present research has been conducted to intensity the production process of TMPTE (trimethylolpropane triester) from rapeseed methyl ester under the influence of ultrasonic irradiation. Ultrasound irradiation is one of the efficient and new methods to intensify the TMPTE production reaction. Ultrasound significantly intensifies the overall process with reduction in energy consumption. The response surfa

    Recent advances in net-zero energy greenhouses and adapted thermal energy storage systems

    Shiva Gorjian, Hossein Ebadi, Gholamhassan Najafi, Shyam Singh Chandel, Hasan Yildizhan
    Journal Papers , Volume 43 , 2021 February 1, {Pages 100940 }

    Abstract

    In agricultural greenhouses, employment of energy-saving strategies along with alternative energy sources has been identified as a potential solution to address the intensive energy consumption of these cultivation facilities. This study investigates the integration of renewable energy technologies, including solar thermal, solar photovoltaic (PV) and photovoltaic-thermal (PVT), geothermal, and biomass with greenhouse cultivation systems as net-Zero Energy Greenhouses (nZEGs). Solar energy is the most abundant renewable energy source that has been successfully used to provide thermal and electrical power requirements of greenhouses. The use of geothermal heat in greenhouses will save primary energy sources (more than 20%) and reduce operati

    A review on bio-lubricant production from non-edible oil-bearing biomass resources in Iran: Recent progress and perspectives

    Sara Almasi, Barat Ghobadian, Gholamhassan Najafi, Masoud Dehghani Soufi
    Journal Papers , 2021 January 4, {Pages 125830 }

    Abstract

    Lubricants are among the largest drivers of global oil demand in the world. The negative environmental impacts resulting from the entry of direct mineral lubricants necessitates the application of bio-lubricants as an excellent alternative to mineral lubricants. The main resources of bio-lubricants are edible/non-edible oils. The use of edible oils as the primary feedstock for bio-lubricant production in developing countries like Iran is being faced with several controversial challenges including the high dependence of the country to edible oils import, the high price of edible oils, the crisis of food shortage, and the negative impact of edible oils on energy security. The application of non-edible oils as a sustainable bio-lubricant resou

    Analytical and Numerical Solution for H-type Darrieus Wind Turbine Performance at the Tip Speed Ratio of Below One.

    Pedram Ghiasi, Gholamhassan Najafi, Barat Ghobadian, Ali Jafari
    Journal PapersInternational Journal of Renewable Energy Development , Volume 10 , Issue 2, 2021 May 1, {Pages }

    Abstract

    H-type Darrieus vertical axis wind turbines (VAWT) have omnidirectional movement capability and can get more power compared to other VAWTs at high tip speed ratios (λ). However, its disadvantages are self-starting inability and low generated power at λ less than 1. The performance of H-type Darrieus wind turbine at λ< 1 was studied using double multiple stream tube (DMST) model and two-dimensional computational fluid dynamic (CFD) simulation. In CFD simulation, the Unsteady Reynolds Averaged Navier-Stokes (URANS) equations were used and the turbulence model was solved with SST k-ω model. The performance of fifteen various wind turbines was determined at fourteen wind velocities by two solution methods. The effect of chord length, solidi

    Analytical and numerical modeling, sensitivity analysis, and multi-objective optimization of the acoustic performance of the herschel-quincke tube

    Hossein Ahmadian, Gholamhassan Najafi, Barat Ghobadian, Seyed Reza Hassan-Beygi, Rob JM Bastiaans
    Journal PapersApplied Acoustics , Volume 180 , 2021 September 1, {Pages 108096 }

    Abstract

    This study presents the assessments of the acoustic performance of a Herschel-Quincke (HQ) tube, which includes sensitivity analysis and multi-objective optimization of its design variables. A proper model introduced using the flow characteristics of the HQ tube. Input variables were frequency (f), temperature (T), the ratio of areas (R), and tube length (L). These variables were chosen to be varied in a specified range to best characterize the exhaust flow in internal combustion engines. Then a proper multi-objective genetic algorithm (MOGA) was developed for the acoustic performance and geometry optimization of a two-duct HQ tube; the objectives were maximizing the transmission loss (TL) and at the same time minimizing the backpressure (B

    A new pneumatic harvester for improvement and facilitation the harvesting of the olive fruits

    Fatemeh Zare, Gholamhassan Najafi, Teimour Tavakoli Hashjin, Alimashallah M Kermani, Pedram Ghiasi
    Journal PapersAdvances in Horticultural Science , Volume 35 , Issue 1, 2021 January 27, {Pages }

    Abstract

    The objective of this study was to measure and evaluate the performance of a New Pneumatic Harvester (NPH) for harvesting the olives fruit and compare the results with those of similar cases. The study involves two sections, namely, the NPH and the collector system. Two oily types of olive ('Mari' and 'Yellow') were selected to evaluate the NPH and the collector system. The randomized complete block design and Duncan's multi-scope test were used for variance analysis and means comparison purposes, respectively. The dependent parameters used to evaluate the NPH were harvesting productivity, harvesting efficiency, and leave downfall percent. Also, the fruit damage was selected for the collector system. Results showed that the NPH can

    Thermal efficiency analysis of the phase change material (PCM) microcapsules

    M Mazlan, M Rahmani-dehnavi, G Najafi, B Ghobadian, SS Hoseini, ...
    Journal Papers , , {Pages }

    Abstract

    Biodiesel fuel purification in a continuous centrifugal contactor separator: An environmental-friendly approach

    E Fayyazi, B Ghobadian, SMS Ardebili, G Najafi, SM Mousavi, BH Samani, ...
    Journal Papers , , {Pages }

    Abstract

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    • ابراهیم , فیاضی شیشوان
    • ریحانه , لونی
    • 1396
      قياسي, پدرام
      طراحي، ساخت، ارزيابي و تحليل عددي ميكرو توربين بادي نوع داريوس بر پايه فناوري پره¬ متغير جهت تامين بخشي از انرژي كلبه سبز
    • 1397
      امين نيري, محمد
    • 1397
      عبدالملكي, سعيد
    • 1398
      بهروزيان, مهرسا
    • 1399
      حسن دوست رستمي, محمدرضا
    • 1399
      كشاورزي, مريم
    • مدیر گروه مکانیک ماشینهای کشاورزی ۹۲-۹۰
    • معاون پژوهشی دانشکده کشاورزی ۹۶-۹۳
    • معاون آموزشی دانشکده کشاورزی از سال ۹۷ تاکنون
    • استاد و پژوهشگر نمونه دانشگاه تربیت مدرس
    • پژوهشگر برتر کشور در سال 1396
    • ثبت اختراع بین المللی آمریکا-US patent: US 2018/0273862 A1. Bio-nano emulsion fuel, Sep. 27, 2018.
    • ثبت اختراع بین المللی آمریکا-US patent: US2019/0284687 A1. Micro wind turbine: An innovative Controllable Shroud for Micro Wind Turbines
    • یک درصد دانشمندان برتر دنیا از سال ۱۳۹۴ تاکنون

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