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Search Results: 1 - 10 of 3085 matches for " Hamid Baseri "
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Study of Tool Wear and Overcut in EDM Process with Rotary Tool and Magnetic Field
Reza Teimouri,Hamid Baseri
Advances in Tribology , 2012, DOI: 10.1155/2012/895918
Abstract: Tool wear and workpiece overcut have been studied in electrical discharge machining process with rotational external magnetic field and rotational electrode. Experiments have been divided to three main regimes, namely, low-energy regime, middle-energy regime, and high-energy regime. The influence of process parameters were investigated on electrode wear rate and overcut. Results indicate that applying a magnetic field around the machining gap increases the electrode wear rate and overcut. Also, rotation of the tool has negative effect on overcut. 1. Introduction Materials such as tool steel, ceramic, metal matrix composite, and Inconel widely are used in die molding, aerospace, surgical and automotive industries. Machining of these materials by using traditional machining is difficult due to high wear and corrosion resistance, hardness, and toughness properties of them. Electrical discharge machining (EDM) is a nontraditional method which is used most commonly to machining of difficult-to-machine materials. Flushing the debris from the machining gap is one of the major challenges in EDM process. Accumulation of debris in gap space causes inactive pulses such as short and open circuit and arc. These types of discharges do not remove any material from the workpiece and damage the surface integrity of machined specimen. By considering these reasons, researchers focus on the methods which improve the flushing in EDM. Methods such as EDM with rotating tool electrode [1–6], ultrasonic vibration assisted EDM [7–10], and compaction of vibration and rotation of electrode [5, 11] were introduced to develop the flushing, the eroded particle in gap space and improve the machining performance. Few researches have investigated the effect of rotary tool on machining characteristics in EDM. Soni and Chakraverti [1] analyzed the effect of rotary electrode tool on the EDM of titanium alloy. They found that the rotary motion of the tool increases the MRR and electrode wear rate (EWR) in all levels of current and pulse on time. Mohan et al. [2, 3] conducted the experimental study on Al-SiC composite material. They showed that the rotary electrode improves the MRR and reduce the surface roughness. Kuppan et al. [4] investigated the effects of various rotational speed of electrode on inconel 718. Results show that the increasing of the rotational speed is effective factor in low discharge energy. Ghoreishi and Atkinson [5] studied the influences of vibration and rotation of electrode on machining characteristics in three levels of machining pulse energy. Saha and Choudhury
Prediction of the Setting Properties of Calcium Phosphate Bone Cement
Seyed Mahmud Rabiee,Hamid Baseri
Computational Intelligence and Neuroscience , 2012, DOI: 10.1155/2012/809235
Abstract: Setting properties of bone substitutes are improved using an injectable system. The injectable bone graft substitutes can be molded to the shape of the bone cavity and set in situ when injected. Such system is useful for surgical operation. The powder part of the injectable bone cement is included of β-tricalcium phosphate, calcium carbonate, and dicalcium phosphate and the liquid part contains poly ethylene glycol solution with different concentrations. In this way, prediction of the mechanical properties, setting times, and injectability helps to optimize the calcium phosphate bone cement properties. The objective of this study is development of three different adaptive neurofuzzy inference systems (ANFISs) for estimation of compression strength, setting time, and injectability using the data generated based on experimental observations. The input parameters of models are polyethylene glycol percent and liquid/powder ratio. Comparison of the predicted values and measured data indicates that the ANFIS model has an acceptable performance to the estimation of calcium phosphate bone cement properties. 1. Introduction Bioactive calcium phosphates such as hydroxyapatite (HA) Ca10(PO4)6(OH)2, tricalcium phosphate (TCP) Ca3(PO4)2, tetracalcium phosphate (Ca4P2O9), and dicalcum phosphate (DCP) CaHPO4 have been widely applied for hard tissue substitute materials, due to their good biocompatibility and bioactivity [1–4]. Many studies have evidenced the excellent biocompatibility of calcium phosphates (CaPs) and their favorable interaction with hard tissue [5, 6]. The shapes of CaPs for the practical uses are classified into the dense and porous CaP blocks [7, 8], the powders and granules [9], the CaP coating [10, 11], and the CaP cement [12, 13]. The hardened forms of CaPs have a major disadvantage. One of the shortcomings is the difficulty of fitting into the defects. The particulate form of CaP can easily fill the defects; however, it migrates or disperses into surrounding tissue [14, 15]. One of the major improvements in CaPs in recent years is the development of an injectable system. The injectable bone graft substitutes can mold to the shape of the bone cavity and set in situ when injected. Such systems should shorten the surgical operation time, reduce the damaging effects of large muscle retraction, decrease the size of the scars and diminish postoperative pain. It also allows the patient to achieve rapid recovery in a cost-effective manner [15, 16]. Calcium phosphate cements (CaPCs) were the first injectable bone filling developed for bone substitute
An investigation on of job satisfaction in accounting and auditing institutions of commercial companies
Saeid Baseri
Management Science Letters , 2013,
Abstract: Experiences in recent years about industrial and official system of the Iran and other countries and successful organizations show that human resource plays an important and principal role in economic and social development of countries & organization. Therefore, fundamental investment is considered and principle utilization of it with the increase in productivity level is one of the certain rules in development and advance of a country or organization. The main objective of this study is to examine the job satisfaction of auditors of audit organizations in comparison to accountants in Business enterprise. In addition, the author tries to analyze the effective factors on job satisfaction in two groups to point to essential guidelines and decrease the job quit in this part of society and increase the efficiency of human resource, even very little. Results obtained from the study hypothesis show that range of dissatisfaction among auditors is more than accountants are.
The Effects of Bone Screw Configurations on the Interfragmentary Movement in a Long Bone Fixed by a Limited Contact Locking Compression Plate  [PDF]
Jalil Nourisa, Amin Baseri, Leszek Sudak, Gholamreza Rouhi
Journal of Biomedical Science and Engineering (JBiSE) , 2015, DOI: 10.4236/jbise.2015.89055
Abstract: The locking compression plates (LCP) are efficient tools in open reduction and internal fixation (ORIF), especially in osteoporotic bones. Two important factors of screw density and screw position can affect the functionality of the bone plate. Several studies have assessed the influence of the screw configurations on the bone-plate stiffness, but the effects of screw positions on the interfragmentary strain, εIF of LCP construct have not been investigated yet. In this study, finite element method was used to investigate the influence of screws number and position on the interfragmentary strain of LCP-femur system for a mid-shaft fracture. Results of this study showed that by insertion of screws closer to the fracture site, εIF decreases by 2nd degree polynomial function versus screw position, but by adding the screws from the ends of the plate, or by moving and placing the screws towards the fracture site, the reduction of εIF will be linear. Results of this study were compared and are in agreement with some studies in the literature, even though their scope was mostly stability of the bone-implant system, whereas our scope was focused on the interfragmentary strain.
Investigation on Numerical Modeling of Water Vapour Condensation from a Flue Gas with High COR2R Content  [PDF]
Hamid Nabati
Energy and Power Engineering (EPE) , 2011, DOI: 10.4236/epe.2011.32023
Abstract: In this paper, condensation of water vapor from a mixture of COR2R/HR2RO is studied numerically. To simplify the study and focus on the physical model, a simple vertical plate was chosen. Two condensation models are developed and numerical approach is considered to implement these models. The main objective in the cur-rent paper was to study the capability of numerical modeling in prediction of complex process. Results showed that developed condensation models in combination with numerical approach can predict the trends in condensation behavior of binary mixture very well. Results from this study can be developed further to be used in design of condensers which are suitable for oxy-fuel power plants.
Optimal Node Scheduling for Desired Percentage of Coverage in Wireless Sensor Networks  [PDF]
Hamid Khosravi
Wireless Sensor Network (WSN) , 2012, DOI: 10.4236/wsn.2012.45018
Abstract: Recent developments in wireless communication and embedded computing technologies have led to the advent of wireless sensor network technology. Hundreds of thousands of these micro sensors can be deployed in many areas including health, environment and battlefield in order to monitor the domain with desired level of accuracy. When wireless sensors are deployed in an area, the lifetime of the network should last as long as possible according to the original amount of energy. Therefore, reducing energy consumption in WSNs is of primary concern. We have proposed a node scheduling solution that solves the coverage and connectivity problem in sensor networks in an integrated manner. In this way we will divide network life time to finite number of rounds and in each round we will generate a coverage bitmap of sensors of the domain and based on this bitmap it will decided which sensors remain active or go to sleep. We will check the connection of the sensor network by using Laplacian of adjancy graph of active nodes in each round. Also the network will be capable of producing desired percentage of coverage by using coverage bitmap. We will define the connected coverage problem as an optimization problem and we will seek a solution for the problem by using Genetic Algorithm optimization method.
Comparative Studies of the Adsorption of Direct Dye on Activated Carbon and Conducting Polymer Composite
J. Raffiea Baseri,P. N. Palanisamy,P. Sivakumar
Journal of Chemistry , 2012, DOI: 10.1155/2012/603196
Abstract: This study analyses the feasibility of removing Direct Blue 71 from aqueous solution by different adsorbents such as activated carbon (TPAC) and Poly pyrrole polymer composite (PPC) prepared from Thevetia Peruviana. Batch mode adsorption was performed to investigate the adsorption capacities of these adsorbents by varying initial dye concentration, temperature, agitation time and pH. The performance of TPAC was compared with PPC. Among the adsorbents, PPC had more adsorption capacity (88.24%) than TPAC (58.82%) at an initial concentration of 50 mg/L and at 30°C. The experimental data best fitted with pseudo second order kinetic model. The adsorption data fitted well for Langmuir adsorption isotherm. Thermodynamic parameters for the adsorbents were also evaluated. The carbon embedded in conducting polymers matrix show better adsorptive properties than activated carbon.
Application of Polyaniline Nano Composite for the Adsorption of Acid Dye from Aqueous Solutions
J.Raffiea Baseri,P.N. Palanisamy,P. Sivakumar
Journal of Chemistry , 2012, DOI: 10.1155/2012/415234
Abstract: In this research, Polyaniline coated sawdust (Polyaniline nano composite) was synthesized via direct chemical polymerization and used as an adsorbent for the removal of acid dye (Acid Violet 49) from aqueous solutions. The effect of some important parameters such as pH, initial concentration of dye, contact time and temperature on the removal efficiency was investigated in batch adsorption system. The adsorption capacity of PAC was high (96.84 %) at a pH of 3-4. The experimental data fitted well for pseudo second order model. Langmuir model is more appropriate to explain the nature of adsorption with high correlation coefficient. The Energy of activation from arrehenius plot suggested that the adsorption of AV49 onto PAC involves physisorption mechanism.
An operator product inequalities for polynomials
M. Ahmadi Baseri,M. Bidkham,M. Eshaghi Gordji
Mathematics , 2009,
Abstract: Let $P(z)$ be a polynomial of degree $n\geq 1$. In this paper we define an operator $B$, as following, $$B[P(z)]:=\lambda_0 P(z)+\lambda_1 (\frac{nz}{2}) \frac{P'(z)}{1!}+\lambda_2 (\frac{nz}{2})^2 \frac{P''(z)}{2!},$$ where $\lambda_0,\lambda_1$ and $\lambda_2$ are such that all the zeros of $$u(z)=\lambda_0 +c(n,1)\lambda_1 z+c(n,2) \lambda_2 z^2$$ lie in half plane $$|z|\leq |z-\frac{n}{2}|$$ and obtain a new generalization of some well-known results.
ANALISIS KEBERLANJUTAN PROGRAM DAERAH PERLINDUNGAN LAUT DENGAN PENDEKATAN ANALYTIC HIERARCHY PROCESS (AHP) DI KABUPATEN RAJA AMPAT
Hamid Hamid
Bumi Lestari , 2013,
Abstract: The aims of this research were (1) to assess the sustainability of the marine sanctuary program in the COREMAP site phase II Raja Ampat; and (2) to find out the parameters which affect the sustainability aspects marine sanctuary program in the COREMAP site phase II Raja Ampat. This research had been conducted in Raja Ampat-West Papua by using survey method and respondents determined by purposive sampling method. The collected data had been analyzed by Analytic Hierarchy Process, or AHP. The results indicated that (1) the sustainability of marine sanctuary program in the COREMAP site phase II Raja Ampat will go on, because the strong indications showed that the comprehensive sustainable value were 2,178 (high category), (2) from 22 evaluated villages, 15 villages (68,2%) have sustainability value by high category and 7 villages (31,8 %) have sustainability value by moderate category (i.e: Villages of Saonek, Yenbeser, Kurkapa, Bianci, Selpele, Yensawai, and Arefi).
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