Sensor less torque and speed control of five level converters for AC drive using SVPWM technique
Various applications, like in underground mines and oil and gas industries, require remote operation of vector-controlled medium-voltage variable speed drives via a long motor feeder. The use of voltage source inverters in such cases leads to motor overvoltage and harmonic quality problems. The current source inverter (CSI) is ideally matched to these applications be-cause of its motor-friendly voltage output. Speed sensorless operation is mandatory due to the long motor feeder. Although the model reference adaptive system (MRAS) is a powerful and proven speed estimation tool, its implementation in long motor feeder drives faces many challenges. Among them, and addressed in this paper, are inherent dc offset in its stator model, the need for actual motor voltage and current values, and oscillations in the estimated speed due to errors in the motor current measurement signals. In this paper, a sensorless CSI vector-controlled drive, suitable for long motor feeder applications, is studied. Improved speed estimation is achieved by proposing 1) a modified dc-offset eliminator for an MRAS speed estimation and 2) a compensation technique for mo-tor current’s measurement errors. Intensive experimental results, for a low-voltage scaled model, along with simulations validate the effectiveness of the proposed technique. In this Proposed Control technique of the space vector modulation Technique (SVPWM) is applied to 5 level inverter controls in the proposed DTC_SVPWM based induction motor drive system, thereby dramatically reducing the torque ripple. Then the controller based on space vector modulation is designed to be applied in the control of Induction Motor (IM) with a three-level Inverter. This type of Inverter has Several advantages over the standard Five-level CSI, such as a greater number of levels in the output voltage waveforms, Lower dv/dt, less harmonic distortion in voltage and current waveforms and lower switching frequencies Eliminated By SVPWM Tech. simulation results are reported to demonstrate its effectiveness. The entire control scheme is implemented with Matlab/Simulink.
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Defective neutrophil chemotaxis in generalized aggressive periodontitis patients in Indian population
Accumulation of neutrophils in the connective tissues and junctional epithelium of the periodontium is a characteristic feature of periodontal disease. The migration of neutrophils into the area may be in response to chemotactic substances elaborated directly by bacteria or by complement-derived chemotactic factors. The function of the neutrophil is thought to be clearance of infecting microorganisms and other noxious substances. It is, therefore, not surprising that a decrease in neutrophil number and function might result in more severe periodontal disease. The aim of the present study was to evaluate the chemotactic response of the neutrophils in a group of patients suffering from generalized aggressive periodontitis. Neutrophils from 10 normal subjects and 10 generalized aggressive patients were isolated from peripheral venous blood and chemotactic response was measured using casein as the chemoattractant. Of the 10 patients analyzed 5 patients showed depressed chemotaxis to casein. Elevated chemotactic responses were seen in remaining patients. Thus all patients recruited in the study showed abnormal neutrophil chemotaxis. The results obtained were not statistically significant. Based on these results it can be concluded that patients of generalized aggressive periodontitis show abnormal chemotactic response.
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The emergence of mental trope in Arabic and Persian literature and its evolution
This article was written with the aim of examining the differing views of the scholars of the art of the trope in the subject of mental trope or tropical predication and tries to compare the different aspects of scholars’ views with an analytical and descriptive method and finally with the help of those scholars’ views and studying the historical evolutionary course of that rhetorical device give a fruitful result to the lovers of the this art. Mental trope is one of the devices of the rhetoric in general and art of the trope in specific that the domain of dialectic and arguments about it goes back to the history of rhetoric and it came to known as propositional trope, trope in proof, and tropical predication. Mental trope is generally about the construction and the structure of the sentence and is beyond the boundary of the word; that is, each single word of the sentence is used in its conventional meaning, however, the construction of the sentence is not in agreement with its real concept. In other words, the verb and verbal group (infinitive, gerund, and past participle) is attributed to an agent other than its real agent.
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Studying the allegorical metaphor and the course of its historical evolution from the perspective of rhetoricians
Allegorical metaphor is a kind of explicit metaphor in which the elliptic tenor as an abstract form of multiple grounds is compared to an explicit vehicle which is an abstract from of multiple grounds either. This figure of speech is a verbal masterpiece of human being and soaring beyond the heaven of the poetic images which has always had many controversies regarding its quality and quantity during its historical course. This descriptive article using content analysis attempts to study and compare the various and different opinions of the scholars of the art of the scheme from commencing of this term to the art of Arabic and Persian rhetoric up to present time to provide the interested readers of the art of the scheme and device of metaphor with a thorough understanding of the historical course and evolution of that figure.
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Effect of cutting positions and growth regulators on rooting ability of Griffonia simplicifolia(Vahl ex DC.) Baill
The effects of growth hormones and cutting positions on stem cuttings of Griffonia simplicifolia were investigated. The stem cuttings were treated with IBA and NAA at 0mg/L, 100mg/L and 200mg/L with different cutting positions (top, middle and bottom). Cuttings were assessed for root length, roots number, shoot number and sprout percent weeks after planting. Highest root length (16.69cm) at upper cutting position and highest root number (4.05) at middle nodal position were observed in cuttings with no auxin. For shoot number (2.94) and sprout percentage weeks after planting (15.18), cuttings with no hormone also had the highest mean value.
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Optimization of the antioxidants of tigernut (Cyperus esculentus L.) during roasting using response surface methodology
Effect of roasting temperature and time on the total polyphenols, flavonoids, total antioxidants and antioxidant properties of tigernut was studied using response surface methodology. Tigernut samples were roasted in an oven at the range of 150 – 200oC for 20 – 50 min. Out of the responses, only radical scavenging activity was not significantly affected by the roasting conditions. Roasting temperature affected the antioxidant contents significantly (p > 0.05) than roasting time. The optimum roasting temperature and time obtained was 200 oC for 20 min. The experimental values were very close to the predicted values and were not significantly (p > 0.05) different.
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Effects of variable viscosity and thermal conductivity on stagnation flow of a micropolar fluid towards a vertical permeable surface
A computer oriented numerical approach to study the effects of variable viscosity and thermal conductivity of stagnation flow of a micropolar fluid towards a vertical permeable surface is investigated in this study. The external flow impinges normal to the heated plate and we have assumed the viscosity and thermal conductivity as the inverse linear function of temperature. The partial differential equations governing the problem under consideration have been transformed into a system of non-linear ordinary differential equations by the similarity transformation and solved them numerically by shooting method. Numerical results are carried out for various dimensionless parameters of the problem especially variable viscosity parameter, thermal conductivity parameter, micro-rotation parameter along with the Prandtl number. The results are presented graphically for velocity distribution, temperature distribution and micropolar distributions for various values of non-dimensional parameters. It is found that the effects of the parameters representing variable property of viscosity and thermal conductivity are significant.
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Information technology and its relationship with dissemination of informal knowledge and organizational learning
The purpose of this study is to investigate the relationship among information technology (IT), dissemination of informal knowledge and organizational learning. This article is implemented based on research findings described in firms with business areas of IT, and is formed as an analysis case in Taran Gostar Company. The literature was studied to develop a theoretical framework for the research model and after the library studies and exploratory interviews, investigate the relationship among IT, dissemination of informal knowledge and organizational learning were assessed through research surveys and questionnaires. Reliability and validity of the questionnaire was confirmed by experts and measured with Cronbach's alpha and also the value of 0.85 was obtained. The SPSS software was used to examine the relationships between the components of knowledge. Results showed a direct and significant correlation (positive) between elements of the research topic. Correlation coefficient between IT and informal knowledge is equal to 0.702 and the correlation between IT and organizational learning is equal to 0.804. In this study, the researcher used a questionnaire based on the range of 5 options. 170 questionnaires were distributed among company employees of Taran Gostar and 102 cases of them were applicable.
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Immediate effect of relaxation on hemodynamic parameters and pulmonary functions in normal individuals
The aim of this study is to know if relaxation has immediate effect on hemodynamic parameters and pulmonary functions in normal healthy individuals. 34 of 40 participants were selected after screening. These participants were divided in two groups, group A: music therapy, group B: Jacobson’s progressive muscle relaxation. After an interval of 5 days, the participants were given the other intervention respectively. The participant’s hemodynamic parameters and pulmonary functions were noted immediately before and after the session. The study was conducted in the department of Cardio respiratory physiotherapy, College of Physiotherapy, PIMS, Loni. India. 34 of 40 normal healthy participants entered the study and 30 completed it. Relaxation was given by two techniques, music therapy in which the participant was made to listen to Indian classical instrumental music for 20 minutes. Another technique used was Jacobson’s progressive muscle relaxation for 20 minutes. Outcome measures were noted pre and post session. The primary outcome measures were hemodynamic parameters and pulmonary function. The secondary outcome measure was to find participant’s preference of relaxation technique based on their experience. The hemodynamic parameters improved considerably after music therapy but the pulmonary functions improved better with Jacobson’s progressive muscle relaxation. The participants rated music therapy more preferable than Jacobson’s progressive muscle relaxation. Relaxation has immediate effect on hemodynamic parameters and pulmonary functions. Relaxation particularly music therapy (Classical Indian instrumental music) can be made a routine activity in normal healthy individuals.
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Locating suitable areas for rain water harvesting
More than 75 percent of Iran is located in arid and semi-arid and faces many hydrological constraints that often are attributed to the lack of rainfall and rainfall distribution. This issue is locating suitable areas for rain water harvestingin Birj and plain however it ismore importance in poor farming communities that are dependent on rain-fed cultivation. To determine the areas those are prone to runoff collection used from a Decision Support System (DSS) and Geographic Information System (GIS)to identify a logical process in relation to harvesting the rainfall and Within this system utilization from Model Builder in Arc GIS 9.3 software. The process defined in this paper uses from runoff capacity for decision and some information such as runoff potential map, distances from residential areas map, irrigated cultivation map and rain-fed cultivation map is inputting in the system. With combination of these maps makes the rain water harvesting prone areas map. The result shows that more than 40 present is in medium class and 32 present is in good class.
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