Periocular Dirofilariasis in a Young Woman

Amir Jamshidi,Mahin Jamshidi,Iraj Mobedi,Mandana Khosroara 대한기생충학열대의학회 2008 The Korean Journal of Parasitology Vol.46 No.4

CFD-based Design and Analysis of the Ventilation of an Electric Generator Model, Validated with Experiments

Jamshidi, Hamed,Nilsson, Hakan,Chernoray, Valery Korean Society for Fluid machinery 2015 International journal of fluid machinery and syste Vol.8 No.2

The efficiency of the ventilation system is a key point for durable and reliable electric generators. The design of such system requires a detailed understanding of the air flow in the generator. Computational fluid dynamics (CFD) has the potential to resolve the lack of information in this field. The present work analyses the air flow inside a generator model. The model is designed using a CFD-based approach, and manufactured by taking into consideration the experimental and numerical requirements and limitations. The emphasis is on the possibility to accurately predict and experimentally measure the flow distribution inside the stator channels. A major part of the work is focused on the design of an intake and a fan that gives an evenly distributed flow with a high flow rate. The intake also serves as an accurate flowmeter. Experimental results are presented, of the total volume flow rate, the total pressure and velocity distributions. Steady-state CFD simulations are performed using the FOAM-extend CFD toolbox. The simulations are based on the multiple rotating reference frames method. The results from the frozen rotor and mixing plane rotor-stator coupling approaches are compared. It is shown that the fan design provides a sufficient flow rate for the stator channels, which is not the case without the fan or with a previous fan design. The detailed experimental and numerical results show an excellent agreement, proving that the results reliable.

Converting of the 2D graphene to its 3D by chicken red blood cells as sheets separator for construction supercapacitor electrode

Jamshidi Fariba,Gholivand Mohammad-Bagher,Amiri Masoud 한국물리학회 2022 Current Applied Physics Vol.37 No.-

Here, we report on a facile green and scalable method for the fabrication of porous 3D graphene as a well-known carbon-based material used in many energy storage devices. Chicken red blood cells were used as sheets spacer and heteroatom sources in the construction of 3D graphene. First, the red blood cells were separated from the blood and mixed with graphene oxide. Then, the mixture was freeze-dried and carbonized at 700 ◦C. The resulted 3D graphene containing heteroatoms was used as a supercapacitor electrode modifier on a glassy carbon electrode and tested with various electrochemical techniques. The supercapacitor electrode showed a specific capacitance of 330 F g-1 at a current density of 1 A g-1, maximum power density of 1958 W kg-1, and maximum energy density of 85 Wh kg-1. Furthermore, the supercapacitive performances were tested in a two-electrode symmetrical system which exhibited a specific capacitance of 238 F g-1 for 1 A g-1. It also showed a power density of 2200 W kg-1 and an appreciable energy density of 160 Wh kg-1. The excellent electrochemical behavior of 3D graphene indicates the promising abilities of the composite for other applications such as biosensors, batteries, electrocatalysts, etc.

Generational Status: An Ignored Variable in Language Learning Studies?

Kobra Jamshidi 아시아영어교육학회 2013 The Journal of Asia TEFL Vol.10 No.2

Self-powered hybrid electromagnetic damper for cable vibration mitigation

Maziar Jamshidi,C.C. Chang,Ali Bakhshi 국제구조공학회 2017 Smart Structures and Systems, An International Jou Vol.20 No.3

This paper presents the design and the application of a new self-powered hybrid electromagnetic damper that can harvest energy while mitigating the vibration of a structure. The damper is able to switch between an energy harvesting passive mode and a semi-active mode depending on the amount of energy harvested and stored in the battery. The energy harvested in the passive mode resulting from the suppression of vibration is employed to power up the monitoring and electronic components necessary for the semi-active control. This provides a hybrid control capability that is autonomous in terms of its power requirement. The proposed hybrid circuit design provides two possible options for the semi-active control: without energy harvesting and with energy harvesting. The device mechanism and the circuitry that can drive this self-powered electromagnetic damper are described in this paper. The parameters that determine the device feasible force-velocity region are identified and discussed. The effectiveness of this hybrid damper is evaluated through a numerical simulation study on vibration mitigation of a bridge stay cable under wind excitation. It is demonstrated that the proposed hybrid design outperforms the passive case without external power supply. It is also shown that a broader force range, facilitated by decoupled passive and semi-active modes, can improve the vibration performance of the cable.

Seismic Behaviour of Slab-on-Girder Steel Bridges Equipped with Ductile Steel Infill Plate End Diaphragms

Morteza Jamshidi,Taksiah A. Majid,Norazura M. Bunnori 한국강구조학회 2015 International Journal of Steel Structures Vol.15 No.2

Damage suffered by slab-on-girder steel bridges during low-to-moderate seismic excitations reveal the deficiency of standards and codes and indicate the necessity of obtaining insight to the lateral load path and the capacity of individual component and assembled systems. In this paper, to improve the seismic performance of this type of bridges, the lateral load path was initially studied. Subsequently, thin steel infill plates were placed on the seismic load path to dissipate the imposed energy. The results indicate that the use of stocky infill plates with common yielding stress as end diaphragms leads to elastic behaviour of the end diaphragm, at least up to displacement corresponded to the ultimate strength of the substructures, whereas thinner infill plates with low yield stress exhibit an appropriate energy dissipation capacity, and a significant amount of transmitted lateral load will be decreased through their plastic deformation.

CFD-based Design and Analysis of the Ventilation of an Electric Generator Model, Validated with Experiments

Hamed Jamshidi,Håkan Nilsson,Valery Chernoray 한국유체기계학회 2015 International journal of fluid machinery and syste Vol.8 No.2

The efficiency of the ventilation system is a key point for durable and reliable electric generators. The design of such system requires a detailed understanding of the air flow in the generator. Computational fluid dynamics (CFD) has the potential to resolve the lack of information in this field. The present work analyses the air flow inside a generator model. The model is designed using a CFD-based approach, and manufactured by taking into consideration the experimental and numerical requirements and limitations. The emphasis is on the possibility to accurately predict and experimentally measure the flow distribution inside the stator channels. A major part of the work is focused on the design of an intake and a fan that gives an evenly distributed flow with a high flow rate. The intake also serves as an accurate flowmeter. Experimental results are presented, of the total volume flow rate, the total pressure and velocity distributions. Steady-state CFD simulations are performed using the FOAM-extend CFD toolbox. The simulations are based on the multiple rotating reference frames method. The results from the frozen rotor and mixing plane rotor-stator coupling approaches are compared. It is shown that the fan design provides a sufficient flow rate for the stator channels, which is not the case without the fan or with a previous fan design. The detailed experimental and numerical results show an excellent agreement, proving that the results reliable.

Sonochemical synthesis of La(OH)3 nanoparticle and its influence on the flame retardancy of cellulose acetate nanocomposite

Parastoo Jamshidi,Davood Ghanbari,Masoud Salavati-Niasari 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.5

In this work, cellulose acetate-La(OH)3 nanocomposites were synthesized via two different in situ and ex situ sonochemical methods. At ex situ firstly lanthanum hydroxide nanostructures were synthesized via sonochemical reaction. The effect of different parameters such as power, time, and surfactants on the morphology of La(OH)3 nanostructures was investigated. Nanostructures were characterized by XRD and SEM. The influence of La(OH)3 nanostructures on the flame retardancy of the cellulose acetate matrix was studied using UL-94 analysis. The enhancement of fame retardancy of nanocomposite is due to endothermically decomposition of La(OH)3 that absorbs energy and simultaneously releases of water.

A Lightweight Algorithm against Replica Node Attack in Mobile Wireless Sensor Networks using Learning Agents

Mojtaba Jamshidi,Shokooh Sheikh Abooli Poor,Nooruldeen Nasih Qader,Mehdi Esnaashari,Mohammad Reza Meybodi 대한전자공학회 2019 IEIE Transactions on Smart Processing & Computing Vol.8 No.1

The node replication attack is considered one of the most dangerous attacks against wireless sensor networks (WSNs). In this attack, an adversary captures one or more normal nodes of the network, extracts its key materials, generates several replicas, and deploys them in the network. In this paper, we propose a novel, intelligent, and lightweight algorithm using learning agents and watchdog nodes (WNs) to detect replica nodes in mobile WSNs. In the proposed algorithm, there are a few WNs, each one equipped with a learning agent that monitors the network traffic and nodes’ movements to identify potential replica nodes in the network. We use the fact that the number of times that a replica node meets a WN is probably more than that of a normal node during a specific monitoring interval of the network. The proposed algorithm is simulated using the J-SIM simulator, and its performance is evaluated in terms of replica node–detection probability and false detection probability through experiments. Experiment results show that the proposed algorithm can detect 100% of the replica nodes, while its false detection probability is less than 0.01.

DSLA: Defending against Selective Forwarding Attack in Wireless Sensor Networks using Learning Automaton

Mojtaba Jamshidi,Mehdi Esnaashari,Shahin Ghasemi,Nooruldeen Nasih Qader,Mohammad Reza Meybodi 대한전자공학회 2020 IEIE Transactions on Smart Processing & Computing Vol.9 No.1

Selective forwarding attacks (SFAs) can harm the mission of critical applications such as military surveillance and forest fire monitoring. In these attacks, malicious nodes behave like normal nodes most of the time, but selectively drop sensitive packets, such as a packet that reports on the movement of opposing forces, and therefore, detection of this kind of attack is hard. In this paper, a fully distributed, dynamic, intelligent, lightweight algorithm based on learning automata is proposed in order to defend against the selective forwarding attack. In this algorithm, an overhearing mechanism, along with the learning automata model, is used to select secure routes for forwarding packets in a multi-hop routing algorithm. Each node is equipped with a learning automaton, which helps the node select the next hop for forwarding its data towards the base station. The proposed algorithm is simulated using J-SIM. Simulation results show the superiority of the proposed algorithm over existing algorithms, such as the single path forwarding algorithm, the multi-hop acknowledge–based algorithm, the multi-data–flow algorithm, the multi-path algorithm, and the neighbor watch system–based algorithm, in packet delivery rate, packet drop rate by malicious nodes, communications overhead, and energy consumption.