OALib Journal期刊

ISSN: 2333-9721




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2018 ( 1 )

2017 ( 124 )

2016 ( 188 )


匹配条件: “ Mohammad Hossein Motevaselian” ,找到相关结果约14785条。
On the Study of Magneto-Hydrodynamic Non-Newtonian Fluid Flow throughout Curvilinear Channel with Corrugated Walls  [PDF]
Seyed Ali Madani Tonekaboni, Hamid Reza Gharahi, Mohammad Hossein Motevaselian, Seyed Fouad Karimian, Sara Jahromi
Open Journal of Modelling and Simulation (OJMSi) , 2014, DOI: 10.4236/ojmsi.2014.24014
Abstract: This article aims to numerically investigate the flow pattern for Newtonian and power law non-Newtonian fluid in a semi-half circular channel with corrugated walls under the influence of a magnetic field. The results indicate that, presence of a magnetic field affects the flow field in several aspects, especially in the vortex creation and dissipation. In addition, the analysis is carried out for different Reynolds numbers to ascertain the influence of magnetic field on each flow regime. Eventually, the analysis is carried out for a range of power indices including pseudo plastic (shear-thinning) to dilatants (shear-thickening) fluids. The results show that by increasing the power-index, the vortices begin to form and grow gradually so that in the shear-thickening fluid an extra vortex is formed and created nearby the corrugated part of the channel.
Information-Driven Collaborative Processing for Diffusive Source Estimation in Wireless Sensor Networks  [PDF]
Hossein Khonsari, Mohammad Hossein Kahaei
Wireless Sensor Network (WSN) , 2010, DOI: 10.4236/wsn.2010.27068
Abstract: This paper discusses an accurate distributed algorithm for diffusive source localization while maintaining the low energy consumption of sensor nodes in wireless sensor networks. In this algorithm, the sensor selection scheme based on the information utility measure is used. To update the estimation in each selected node, a neighborhood radius equal to the communication range of the sensor nodes is defined and all sensors located in the neighborhood circle, whose radius is equal to the neighborhood radius and the selected node is its centre, collaborate their information. To decrease the energy consumption, the neighborhood radius is reduced gradually based on the error covariance value of the estimation. In addition, this paper includes a new method for the initial point calculation which is important in the recursive methods used for distributed algorithms in wireless sensor networks. Numerical examples are used to study the performance of the algorithms. Simulation results show the accuracy of the new algorithm becomes better while its energy consumption is low enough.
Evaluating the Efficacy of Remifentanil-Propofol versus Isoflurane in Reducing Blood Loss with Considering Depth of Anesthesia during Endoscopic Sinus Surgery  [PDF]
Mohammad Ali Haghbin, Hossein Hakimzadeh, Mohammad Shabani
Neuroscience & Medicine (NM) , 2013, DOI: 10.4236/nm.2013.42009

Several methods have been suggested to decrease bleeding during surgery, one of which is the usage of hypotensive anesthetic agents. Endoscopic Sinus Surgery (ESS) is one of the surgeries which need a clear field and the amount of bleeding profoundly impacts the ability of surgeons. Current study was designed to evaluate the effect of remifentanil combined with propofol versus Isoflurane on blood loss during ESS and its possible interaction with Depth of Anesthesia. Fifty one patients comprising 15 females and 36 males undergoing ESS were chosen for this study. One group received propofol and remifentanil to induce and maintain anesthesia and the second group received Isoflurane. Mean Arterial Blood Pressure (MAP), Depth of Anesthesia and total blood loss were recorded for the patients of both group. Data were analyzed using t-test, Repeated Measures ANOVA and Pearson’s correlation. P < 0.05 was considered statistically significant. Both agents induced hypotension during surgery. No significant difference was observed in total blood loss between two groups. DA was decreased in both groups, but no significant correlation was found between DA and MAP or DA and blood loss. There is no significant difference between remifentanil combined with propofol and Isoflurane in decreasing blood loss during ESS, thus we suggest usage of hypotensive anesthetic agent regardless of its type is ESS.

Numerical Simulation of Non-Newtonian Pseudo-Plastic Fluid in a Micro-Channel Using the Lattice Boltzmann Method  [PDF]
Hossein Hamedi, Mohammad Hassan Rahimian
World Journal of Mechanics (WJM) , 2011, DOI: 10.4236/wjm.2011.15029
Abstract: In this paper, the power-law model for a non-Newtonian (pseudo-plastic) flow is investigated numerically. The D2Q9 model of Lattice Boltzmann method is used to simulate the micro-channel flow with expansion geometries. This geometry is made by two squared or trapezoid cavities at the bottom and top of the channel which can simulate an artery with local expansion. The cavities are displaced along the channel and the effects of the displacements are investigated for inline structures and staggered ones (anti-symmetric expansion). The method is validated by a Poiseuille flow of the power-law fluid in a duct. Validation is performed for two cases: The Newtonian fluid and the shear thinning fluid (pseudo-plastic) with n = 0.5. The results are discussed in four parts: 1) Pressure drop; It is shown that the pressure drop along the channel for inline cavities is much more than the pressure drop along the staggered structures. 2) Velocity profiles; the velocity profiles are sketched at the centerline of the cavities. The effects of pseudo-plasticity are discussed. 3) Shear stress distribution; the shear stress is computed and shown in the domain. The Newtonian and non-Newto- nian fluids are discussed and the effect of the power n on shear stress is argued. 4) Generated vortices in the cavities are also presented. The shape of the vortices is depicted for various cases. The results for these cases are talked over and it is found that the vortices will be removed for flows with n smaller than 0.5.
Video Compression USING a New Active Mesh Based Motion Compensation Algorithm in Wavelet Sub-Bands  [PDF]
Mohammad Hossein Bisjerdi, Alireza Behrad
Journal of Signal and Information Processing (JSIP) , 2012, DOI: 10.4236/jsip.2012.33048
Abstract: In this paper, a new mesh based algorithm is applied for motion estimation and compensation in the wavelet domain. The first major contribution of this work is the introduction of a new active mesh based method for motion estimation and compensation. The proposed algorithm is based on the mesh energy minimization with novel sets of energy functions. The proposed energy functions have appropriate features, which improve the accuracy of motion estimation and compensation algorithm. We employ the proposed motion estimation algorithm in two different manners for video compression. In the first approach, the proposed algorithm is employed for motion estimation of consecutive frames. In the second approach, the algorithm is applied for motion estimation and compensation in the wavelet sub-bands. The experimental results reveal that the incorporation of active mesh based motion-compensated temporal filtering into wavelet sub-bands significantly improves the distortion performance rate of the video compression. We also use a new wavelet coder for the coding of the 3D volume of coefficients based on the retained energy criteria. This coder gives the maximum retained energy in all sub-bands. The proposed algorithm was tested with some video sequences and the results showed that the use of the proposed active mesh method for motion compensation and its implementation in sub-bands yields significant improvement in PSNR performance.
Management and Reduction of Chemical Nitrogen Consumption in Agriculture  [PDF]
Abedin Zafari, Mohammad Hossein Kianmehr
American Journal of Plant Sciences (AJPS) , 2012, DOI: 10.4236/ajps.2012.312A224

Nitrogen is an effective material for improving the crop production. There is a big concern about rising chemical nitrogen usage as fertilizer in soil, because some forms of nitrogen absorbs in soil and causes an increase of environment and water pollution and decrease fertilizer efficiency. Composted cow manure is an important resource of organic nitrogen which improves the soil conditions. However, low density of composted cow manure and inconstant nutrient content are two factors that limit the application of composted cow manure. The densification technology is an effective solution for both problems. In this research first the capability of single screw extruder for production of fertilizer pellets including composted cow manure and nitrogen fertilizer was studied and then the effect of fertilizer pellet on the reduction of chemical nitrogen consumption was evaluated. The response of basil plants was determined in three treatments: T1 control (no fertilizer), T2 (nitrogen fertilizer) and T3 (pellet). The results showed that pelletization can be used as a proper method for slow-release nitrogen fertilizer; enhance nitrogen uptake and reducing the chemical nitrogen consumption. The results also showed that all basil responses (chlorophyll content, total weight, leaves weight, root weight and leaf area) were significantly affected by application of N fertilizer and pellet. While maximum recorded parameters were observed with application pellet.

The Overload Reduction in SIP Servers through Exact Regulation of the Retransmission Timer of the Invite Message  [PDF]
Ahmadreza Montazerolghaem, Mohammad Hossein Yaghmaee
Journal of Computer and Communications (JCC) , 2013, DOI: 10.4236/jcc.2013.12002

To initiate voice, image, instant messaging and general multimedia communication, the Session communication must initiate between two participants. SIP (Session initiation protocol) is an application layer control, which task is creating management, and terminating this kind of Sessions. With regard to the independence of SIP from the Transport layer protocols, the SIP messages can be transferred on a variety of Transport layer protocols such as TCP or UDP. The mechanism of Retransmission, which has been embedded in SIP, is able to compensate the missing Packet loss, if needed. The application of this mechanism is when SIP messages are transmitted on an unreliable transmission layer protocol such as UDP. This mechanism, while facing with SIP proxy with overload, causes excessive filling of proxy queue, delays the increase of other contacts and adds the amount of the proxy overload. We in this article, while using UDP, as the Transport layer protocol, by regulating the Invite Retransmission Timer appropriately (T1), have improved the SIP functionality. Therefore, by proposing an Adaptive Timer of Invite message retransmission, we have tried to improve the time of Session initiation and as a result, improving the performance. The performance of the proposed SIP, by the SIPP software in a real network environment has been implemented and evaluated and its accuracy and performance has been demonstrated.

Examining the Relationship of Organizational Agility and Organizational Forgetting with Organizational Effectiveness  [PDF]
Gholamreza Mohammad Ghasemi, Hossein Jenaabadi
Journal of Service Science and Management (JSSM) , 2015, DOI: 10.4236/jssm.2015.83045
Abstract: This study aimed to investigate the relationship of organizational agility and organizational forgetting with organizational effectiveness among staff of the education administration of Zahedan. The population of this study included a total of 645 staff of the education administration of Zahedan who served in the 2013-14 school year. Using the Krejcie-Morgan table, 200 individuals were selected through applying stratified random method. To collect data, three questionnaires including Organizational Agility [1], Organizational Forgetting [2] and Organizational Effectiveness [3] were used. Content validity of these questionnaires was approved by the faculty members of the Department of Management and confirmatory factor analysis was used to ensure the results. In addition, Cronbach’s alpha for the scales of organizational agility, organizational effectiveness and organizational forgetting was calculated, which was 0.73, 0.74 and 0.76, respectively. The results showed that there was a significant positive correlation between organizational agility and organizational effectiveness. Moreover, there was a significant positive relationship between organizational forgetting and organizational agility. In addition, there was a significant positive relationship between organizational forgetting and the components of organizational effectiveness. Additionally, there was a significant positive correlation between organizational agility and the components of organizational effectiveness.
Microbial Community from MTBE-Contaminated Soil for Aerobic Biodegradation of MTBE  [PDF]
Bahareh Montazeri, Mohammad Hossein Sarrafzadeh
Journal of Geoscience and Environment Protection (GEP) , 2016, DOI: 10.4236/gep.2016.41011
Abstract: This Methyl tert-butyl ether (MTBE) is one of the main additives in gasoline to increase octane rating and consequently reduce air pollution. The physico-chemical properties of this substance (high water solubility, low sorption in soil) result in high mobility and considerable concentrations in aquifers. In this survey, Isfehan Refinery that was encountered with MTBE contamination problem was selected as a case study and the MTBE degradation ability of this contaminated area by its indigenous microorganisms was investigated. In the first step of this survey, the influence of various factors on the aerobic degradation of MTBE such as mixed culture type, incubation time, microbial culture and optimal concentration of MTBE were investigated in shaking flasks and the most important factors were specified by means of fractional factorial design 1/2. In the second stage by using optimal values which obtained from the first stage, the effects of co-substare parameter and inoculum parameter were assayed by means of response surface method. The results of the experiments showed that the mixed culture type and initial concentration of MTBE were the most significant factors. The results of the experiments showed that the mixed indigenous culture acted better than activated sludge. The initial concentration of MTBE was also one of the most significant factors. At the best condition about 31 percent of MTBE was treated by co-substrating with n-hexane in a ratio of 0.2.
Tree Based Energy and Congestion Aware Routing Protocol for Wireless Sensor Networks  [PDF]
Amir Hossein Mohajerzadeh, Mohammad Hossien Yaghmaee
Wireless Sensor Network (WSN) , 2010, DOI: 10.4236/wsn.2010.22021
Abstract: Wireless Sensor Networks (WSNs) have inherent and unique characteristics rather than traditional networks. They have many different constraints, such as computational power, storage capacity, energy supply and etc; of course the most important issue is their energy constraint. Energy aware routing protocol is very important in WSN, but routing protocol which only considers energy has not efficient performance. Therefore considering other parameters beside energy efficiency is crucial for protocols efficiency. Depending on sensor network application, different parameters can be considered for its protocols. Congestion management can affect routing protocol performance. Congestion occurrence in network nodes leads to increasing packet loss and energy consumption. Another parameter which affects routing protocol efficiency is providing fairness in nodes energy consumption. When fairness is not considered in routing process, network will be partitioned very soon and then the network performance will be decreased. In this paper a Tree based Energy and Congestion Aware Routing Protocol (TECARP) is proposed. The proposed protocol is an energy efficient routing protocol which tries to manage congestion and to provide fairness in network. Simulation results shown in this paper imply that the TECARP has achieved its goals.

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