Feasibility of using biogas in a micro turbine for supplying heating, cooling and electricity for a small rural building

Rajaei, Gh.,Atabi, F.,Ehyaei, M.A. Techno-Press 2017 Advances in energy research Vol.5 No.2

In this study, the use of a micro gas turbine system using biogas to supply heating, cooling and electricity loads of a rural building located in rural area around Tehran has been studied. Initially, the amount of energy needed by the farmhouse was calculated and then the number of needed microturbines was determined. Accordingly, the amount of substances entering biogas digester as well as tank volume were determined. The results of this study showed that village house loads including electrical, heating and cooling and hot water loads can be supplied by using a microturbine with a nominal power of 30 kW and $33.5m^3/day$ of biogas. Digester tank and reservoir tank volumes are $67m^3$ and $31.2m^3$, respectively. The cost of electricity produced by this system is 0.446 US$/kWh. For rural area in Iran, this system is not compatible with micro gas turbine and IC engine system use urban natural gas due to low price of natural gas in Iran, but it can be compatible by wind turbine, photovoltaic and hybrid system (wind turbine& photovoltaic) systems.

Behavioral switching model for current-fed Cockcroft-Walton voltage multiplier

Rajaei, Amirhossein,Dehghanian, Iman,Shahparasti, Mahdi,Poursmaeil, Edris The Korean Institute of Power Electronics 2020 JOURNAL OF POWER ELECTRONICS Vol.20 No.2

After about 80 years of introducing the Cockcroft-Walton (CW) circuit, it is still widely used because of its advantages, such as simplicity and high step-up gain. Several studies focused on the performance and design optimization of the circuit, but a dynamic model of the circuit remains to be established. This study analyzed the operation principles of an n-stage current-fed Cockcroft-Walton (CF-CWVM) during transient and steady-state operations. Then, an approach was derived to achieve a mathematical model for CF-CWVM with an arbitrary number of stages. A mathematical model for one- and two-stage CF-CWVM was developed, and its results were compared with simulation results. The theoretical model and simulations were validated by providing a prototype of CF-CWVM and comparing the results with the model outputs.

A Study of Velvet Hand Illusion on Fingers Towards Tactile Displays

Nader Rajaei,Masahiro Ohka,Tetsu Miyaoka 대한기계학회 2013 대한기계학회 춘추학술대회 Vol.2013 No.5

Antihyperglycemic and Antioxidant Activity of Crocin in Streptozotocin-Induced Diabetic Rats

Ziba Rajaei,Mousa-Al-Reza Hadjzadeh,Habibollah Nemati,Mahmoud Hosseini,Marzieh Ahmadi,Somayeh Shafiee 한국식품영양과학회 2013 Journal of medicinal food Vol.16 No.3

The aim of the present study was to investigate the antihyperglycemic and protective potential of crocin, a pharmacologically active constituent of Crocus sativus L., in streptozotocin-induced diabetic rats. Rats were administered crocin intraperitoneally at doses of 15, 30, and 60 mg/kg of body weight for 6 weeks. The levels of thiobarbituric acid reactive substance (TBARS) and total thiol (SH) groups were measured in the liver and kidney at the end of 6 weeks. Under our experimental conditions, crocin at a dose of 60 mg/kg was found to significantly reduce the blood glucose level in diabetic animals. In addition, there was a significant increase in TBARS levels and decreased total thiol concentrations in the liver and kidney of diabetic animals. Crocin, at doses of 30 and 60 mg/kg, appears to exert an antioxidative activity demonstrated by a lowering of lipid peroxidation levels in these organs. In conclusion, our findings suggest that crocin has the hypoglycemic and antioxidative properties in streptozotocin-induced diabetes and it may be useful in the management of diabetic patients

Comparison of Root Anatomy and Xylem Vessel Structure in Rain-fed and Supplementary Irrigated ‘Yaghooti-Syah Shiraz’ Grapevine (Vitis vinifera L.)

Homa Rajaei,Parisa Yazdanpanah,Marjan Dadbin,Ali Akbar Kamgar Haghighi,Ali Reza Sepaskhah,Tahereh Eslamzadeh 한국원예학회 2013 Horticulture, Environment, and Biotechnology Vol.54 No.4

Changes in environmental conditions may lead to modifications in structural development of plant root. Effects of supplementary irrigation and soil depths (0-90 cm) on anatomical changes in xylem were investigated in rain-fed Vitis vinifera L. cv. Yaghooti-Syah Shiraz. Irrigated and control roots were prepared according to routine histological procedure. Light microscopic observations revealed the structural features of drought tolerant control roots and their changes after the treatment. Irrigated roots were characterized by the absence of starch grains in parenchyma cells, uniformity of parenchymatous pith cells, and a decrease in periderm thickness. Morphometric investigation of xylem showed that irrigated and deep roots had larger mean and maximum vessel diameter and fewer vessel number than rain-fed and shallow roots, at every soil depth of every treatment. Secondary xylem vessel diameter and number were more affected by irrigation and soil depths than metaxylem. Grape roots responded to supplementary irrigation and increasing soil depth by reducing protective and supporting tissues and increasing vessel diameter.

Effects of the Carrier Relaxation Lifetime and Inhomogeneous Broadening on the Modulation Response of InGaAs/GaAs Self-assembled Quantum-dot Lasers

Alireza Fali,Esfandiar Rajaei,Danesh Kaftroudi 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.64 No.1

In this paper, a theoretical model is used to investigate the lasing characteristics of InGaAs/GaAsquantum-dot lasers. The rate equations for InGaAs/GaAs are numerically solved using the fourthorderRunge-Kutta method. Self-assembled quantum-dot lasers are studied considering the homogeneousand inhomogeneous broadening of the optical gain, as well as the nonlinear gain and thermalcarrier escape from quantum dots. For different carrier relaxation times, the current-output powercharacteristics and light emissions of the quantum-dot laser have been calculated. The effect of thecoverage factor is studied, and an optimized value is introduced for each carrier relaxation time. Moreover, the modulation responses for various inhomogeneous broadening and relaxation timesare presented. Simulated results show that increasing the relaxation time decreases the modulationbandwidth. Furthermore, an increase in inhomogeneous broadening decreases the modulationbandwidth.

Regeneration of catalyst clay soils (Tonsil CO 610 G) by supercritical carbon dioxide

Feridun Esmaeilzadeh,Hamid Rajaei,Ali Akbar Golchehreh,Ali Zeinolabedini Hezave 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.4

Extraction of deactivatived materials from contaminated clay soils (Tonsil CO 610 G) by supercritical carbon dioxide was investigated. Effect of different conditions including extraction temperature (308.15-338.15 K) and pressure (100-330 bar) (thermodynamic conditions), flow rate (4.2-42.6 cc/min), and static time (45-85 min) were investigated to find the optimum conditions for extraction of deactivatived materials. Based on the different experiments, optimum conditions for flow rate (4.2 cc/min), static time (85 min) and extraction pressure and temperature (330 bar and 313.15K) were obtained. In addition, the GC-MS analysis and Bromine index (BI) analysis were revealing that the clay soil is activated and could be used as catalyst again.

Investigation into Hand Impact Force During Forward Falls on Uneven Terrain

Saeed Abdolshah,Nader Rajaei,Yasuhiro Akiyama,Yoji Yamada,Shogo Okamoto 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.3

Outdoor falls predominantly occur because of environmental factors, such as tripping caused by uneven terrain; as a result, the faller may land on an uneven surface. Forward falls are among the most frequent causes of fractures. Previous investigations concentrated on the evaluation of impact forces acting on the hand/wrist on even terrains; however, further studies are necessary to evaluate the impact force during forward falls on uneven surfaces, which may occur frequently in daily activities. This study investigated the distal/proximal hand impact force during forward falls on even/uneven terrain. A series of fall experiments in which the distal and proximal areas of the hand contacted the ground simultaneously (even surface) or at different times (uneven surface) was conducted. The results showed that the magnitude of the peak impact forces acting on the distal and proximal areas are strongly associated with the terrain shape and the contact timing. Although in all experiments, a significant portion of the impact force was exerted on the proximal area of the hand, the earlier distal-ground contact reduced the peak proximal impact force significantly. The results of this study are beneficial for finding strategies to reduce fall-related injuries and the design of protective gloves and wrist guards to satisfy fracture prevention requirements.

Effects of Melatonin on Sleep Quality and Disease Activity in Patients With Rheumatoid Arthritis

Palimi Tayebeh,Zilaee Marzie,Rajaei Elham,Karandish Majid 대한수면학회 2022 sleep medicine research Vol.13 No.1

Background and Objective In rheumatoid arthritis (RA) patients sleep disturbance is one of serious and prevalent problems. Considering the known effects of melatonin on sleep quality and inflammation, this study aimed to investigate melatonin supplementation effect on quality of sleep and disease activity in patients with RA.Methods In this randomized, placebo-controlled trial (double-blind), 64 RA patients were selected and divided into experimental and placebo groups randomly; experimental group received 3 mg/d of melatonin and another group consumed placebo for 60 days. Before and after the investigation, assessment of the quality of sleep determined using the Pittsburgh Sleep Quality Index (PSQI). Disease Activity Score-28 (DAS28) and the Visual Analogue Scale (VAS) questionnaires were used for evaluation of disease activity and pain intensity, respectively.Results Melatonin significantly reduced PSQI, DAS28 and VAS scores, when values compared with baseline. In contrast to placebo group, good sleep quality within the melatonin group increased significantly compared to baseline and this improvement in sleep quality was significant when compared between groups. The scores of DAS28 and pain VAS at the end of trial were significantly reduced compared to the baseline in both groups. However, reduction in the DAS28 and VAS scores of the melatonin group were stronger than reductions in the placebo receiving group.Conclusions This study results revealed that melatonin was safe and effective in improving sleep quality and reducing DAS28 and pain VAS scores in RA patients.

Design and Optimization of Parallel Hybrid Electric Vehicle (PHEV) Drivetrain based on Mechatronics Design Approach

Omid Movahhedi,Farzad Rajaei Salmasi 제어로봇시스템학회 2008 제어로봇시스템학회 국제학술대회 논문집 Vol.2008 No.10

High fuel consumption and air pollution of conventional vehicles besides increasing growth of oil price have caused Hybrid electric vehicles (HEV) to attract more interests for research and development. HEV have two or more sources of power, along which power flow is done by a controller. Different structures of these vehicles exist. In this paper, parallel structure has been considered. Internal Combustion Engine (ICE) and battery provide power for the drive train. Proper selection of vehicle components based upon a drive cycle, through which a vehicle may travel, is critical. Drive train components are determined by optimization of a few cost functions such as fuel consumption; air pollution and operating cost of drivetrain elements. NSGA-II (Non-dominated Sorting Genetic Algorithm-II) is proposed as an optimization tool. Results of the optimization problem are compared with the conventional design procedure based on target performance for the vehicle.