Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 9

Search results for: Sobhan Badakhshan

9 Water Saving in Electricity Generation System Considering Natural Gas Limitation

Authors: Mehdi Ganjkhani, Sobhan Badakhshan, Seyedvahid Hosseini


Power plants exploit striking proportion of underground water consumption. Correspondingly, natural gas-fired power plants need less water than the other conventional power plants. Therefore, shifting unit commitment planning toward these power plants would help to save water consumption. This paper discusses the impacts of water consumption limitation on natural gas consumption and vice versa as a short-term water consumption management solution. To do so, conventional unit commitment problem is extended by adding water consumption and natural gas constraints to the previous constrains. The paper presents the impact of water saving on natural gas demands as well as natural gas shortage on water demand. Correspondingly, the additional cost of electricity production according to the aforementioned constraints is evaluated. Finally, a test system is applied to investigate potentials and impacts of water saving and natural gas shortage. Different scenarios are conducted and the results are presented. The results of the study illustrate that in order to use less water for power production it needs to use more natural gas. Meanwhile, natural gas shortage causes to utilize more amount of water in aggregate.

Keywords: electric energy generation system, underground water sources, unit commitment, water consumption saving, natural gas

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8 Proposing a Failure Criterion for Cohesionless Media Considering Cyclic Fabric Anisotropy

Authors: Ali Noorzad, Ehsan Badakhshan, Shima Zameni


The present paper is focused on a generalized failure criterion for geomaterials with cross-anisotropy. The cyclic behavior of granular material primarily depends on the nature and arrangement of constituent particles, particle size, and shape that affect fabric anisotropy. To account for the influence of loading directions on strength variations, an anisotropic variable in terms of the invariants of the stress tensor and fabric into the failure criterion is proposed. In an extension to original CANAsand constitutive model two concepts namely critical state and compact state play paramount roles as all of the moduli and coefficients are related to these states. The applicability of the present model is evaluated through comparisons between the predicted and the measured results. All simulations have demonstrated that the proposed constitutive model is capable of modeling the cyclic behavior of sand with inherent anisotropy.

Keywords: fabric, cohesionless media, cyclic loading, critical state, compact state, CANAsand constitutive model

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7 Voltage Controlled Ring Oscillator for RF Applications in 0.18 µm CMOS Technology

Authors: Mohammad Arif Sobhan Bhuiyan, Zainal Abidin Nordin, Mamun Bin Ibne Reaz


A compact and power efficient high performance Voltage Controlled Oscillator (VCO) is a must in analog and digital circuits especially in the communication system, but the best trade-off among the performance parameters is a challenge for researchers. In this paper, a design of a compact 3-stage differential voltage controlled ring oscillator (VCRO) with low phase noise, low power and higher tuning bandwidth is proposed in 0.18 µm CMOS technology. The VCRO is designed with symmetric load and positive feedback techniques to achieve higher gain and minimum delay. The proposed VCRO can operate at tuning range of 3.9-5.0 GHz at 1.6 V supply voltage. The circuit consumes only 1.0757 mW of power and produces -129 dbc/Hz. The total active area of the proposed VCRO is only 11.74 x 37.73 µm2. Such a VCO can be the best choice for compact and low-power RF applications.

Keywords: CMOS, VCO, VCRO, oscillator

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6 Design of a High Performance T/R Switch for 2.4 GHz RF Wireless Transceiver in 0.13 µm CMOS Technology

Authors: Mohammad Arif Sobhan Bhuiyan, Mamun Bin Ibne Reaz


The rapid advancement of CMOS technology, in the recent years, has led the scientists to fabricate wireless transceivers fully on-chip which results in smaller size and lower cost wireless communication devices with acceptable performance characteristics. Moreover, the performance of the wireless transceivers rigorously depends on the performance of its first block T/R switch. This article proposes a design of a high performance T/R switch for 2.4 GHz RF wireless transceivers in 0.13 µm CMOS technology. The switch exhibits 1- dB insertion loss, 37.2-dB isolation in transmit mode and 1.4-dB insertion loss, 25.6-dB isolation in receive mode. The switch has a power handling capacity (P1dB) of 30.9-dBm. Besides, by avoiding bulky inductors and capacitors, the size of the switch is drastically reduced and it occupies only (0.00296) mm2 which is the lowest ever reported in this frequency band. Therefore, simplicity and low chip area of the circuit will trim down the cost of fabrication as well as the whole transceiver.

Keywords: CMOS, ISM band, SPDT, t/r switch, transceiver

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5 Study on the Quality of Biscuits Prepared from Wheat Flour and Cassava Flour

Authors: Ramim Tanver Rahman, Muhammad Mahbub Sobhan, M. A. Alim


This study reports on processing of biscuits using skinned, treated and dried cassava flour. Five samples of biscuits S2, S3, S4, S5, and S6 containing 8, 16, 24, 32, and 40% cassava flour with wheat flour and a control sample (S1) containing no cassava flour were processed. The weights of all the biscuit samples were higher than that of control biscuit. The biscuit containing cassava flour was lower width than the control biscuit. The spread ratio of biscuits with 16% cassava flour was higher than other combinations of cassava flour. No remarkable changes in moisture content, peroxide value, fatty acid value, texture, and flavor were observed up to 4 months of storage in ambient conditions (27° to 35°C). A decreasing trend in color, flavor, texture and overall acceptability was observed with the increased incorporation of cassava flour. The sample S1 (no cassava flour) secured the highest overall acceptability and sample S6 (40% cassava flour) obtained the lowest overall acceptability. It is recommended that good quality cassava flour fortified biscuits may be processed in industrial-scale substituting the wheat flour by cassava flour up to 24% levels.

Keywords: cassava flour, wheat flour, shelf life, spread ratio, storage, biscuit

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4 Measurement of Convective Heat Transfer from a Vertical Flat Plate Using Mach-Zehnder Interferometer with Wedge Fringe Setting

Authors: Divya Haridas, C. B. Sobhan


Laser interferometric methods have been utilized for the measurement of natural convection heat transfer from a heated vertical flat plate, in the investigation presented here. The study mainly aims at comparing two different fringe orientations in the wedge fringe setting of Mach-Zehnder interferometer (MZI), used for the measurements. The interference fringes are set in horizontal and vertical orientations with respect to the heated surface, and two different fringe analysis methods, namely the stepping method and the method proposed by Naylor and Duarte, are used to obtain the heat transfer coefficients. The experimental system is benchmarked with theoretical results, thus validating its reliability in heat transfer measurements. The interference fringe patterns are analyzed digitally using MATLAB 7 and MOTIC Plus softwares, which ensure improved efficiency in fringe analysis, hence reducing the errors associated with conventional fringe tracing. The work also discuss the relative merits and limitations of the two methods used.

Keywords: Mach-Zehnder interferometer (MZI), natural convection, Naylor method, Vertical Flat Plate

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3 Female Entrepreneurship and Cultural Influence in Emerging Economy: The Case of Bangladesh

Authors: Nawreen Sobhan, Abeer Hassan, Dina Nziku


There has been a dramatic rise in the percentage of female entrepreneurship in both developed and developing countries as it is now considering as an important source of economic growth. Therefore, there has been a growing research interest in female entrepreneurship as they represent an unrecognized engine for economic growth especially in transition economy. This study will determine the role of cultural influence on female entrepreneurship in the growth of economic development which will add new dimensions to the field of female entrepreneurial studies in informal sector of Bangladesh. A systematic literature review has been conducted on female entrepreneurship and cultural studies in both developed and developing country in this research study. There is lack of research on this field as most of the cultural studies on female entrepreneurship have been conducted globally and most of them are either comparative or based on single developed country. This study addresses this gap by using North’s institutional theory to investigate the influence of socio cultural factors on the development of businesses run by female entrepreneurs in Bangladesh. The study, therefore, has practical implications for policy makers and enhancing micro business performance by female entrepreneurs and contributes to the on-going theoretical understanding of cultural influence in female entrepreneurship in an Asian context.

Keywords: culture, socio cultural factors, female entrepreneurship, informal sectors, formal and informal institution and sustainable economic development

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2 Using of the Fractal Dimensions for the Analysis of Hyperkinetic Movements in the Parkinson's Disease

Authors: Sadegh Marzban, Mohamad Sobhan Sheikh Andalibi, Farnaz Ghassemi, Farzad Towhidkhah


Parkinson's disease (PD), which is characterized by the tremor at rest, rigidity, akinesia or bradykinesia and postural instability, affects the quality of life of involved individuals. The concept of a fractal is most often associated with irregular geometric objects that display self-similarity. Fractal dimension (FD) can be used to quantify the complexity and the self-similarity of an object such as tremor. In this work, we are aimed to propose a new method for evaluating hyperkinetic movements such as tremor, by using the FD and other correlated parameters in patients who are suffered from PD. In this study, we used 'the tremor data of Physionet'. The database consists of fourteen participants, diagnosed with PD including six patients with high amplitude tremor and eight patients with low amplitude. We tried to extract features from data, which can distinguish between patients before and after medication. We have selected fractal dimensions, including correlation dimension, box dimension, and information dimension. Lilliefors test has been used for normality test. Paired t-test or Wilcoxon signed rank test were also done to find differences between patients before and after medication, depending on whether the normality is detected or not. In addition, two-way ANOVA was used to investigate the possible association between the therapeutic effects and features extracted from the tremor. Just one of the extracted features showed significant differences between patients before and after medication. According to the results, correlation dimension was significantly different before and after the patient's medication (p=0.009). Also, two-way ANOVA demonstrates significant differences just in medication effect (p=0.033), and no significant differences were found between subject's differences (p=0.34) and interaction (p=0.97). The most striking result emerged from the data is that correlation dimension could quantify medication treatment based on tremor. This study has provided a technique to evaluate a non-linear measure for quantifying medication, nominally the correlation dimension. Furthermore, this study supports the idea that fractal dimension analysis yields additional information compared with conventional spectral measures in the detection of poor prognosis patients.

Keywords: correlation dimension, non-linear measure, Parkinson’s disease, tremor

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1 Examination of the Main Behavioral Patterns of Male and Female Students in Islamic Azad University

Authors: Sobhan Sobhani


This study examined the behavioral patterns of student and their determinants according to the "symbolic interaction" sociological perspective in the form of 7 hypotheses. Behavioral patterns of students were classified in 8 categories: religious, scientific, political, artistic, sporting, national, parents and teachers. They were evaluated by student opinions by a five-point Likert rating scale. The statistical population included all male and female students of Islamic Azad University, Behabahan branch, among which 600 patients (268 females and 332 males) were selected randomly. The following statistical methods were used: frequency and percentage, mean, t-test, Pearson correlation coefficient and multi-way analysis of variance. The results obtained from statistical analysis showed that: 1-There is a significant difference between male and female students in terms of disposition to religious figures, artists, teachers and parents. 2-There is a significant difference between students of urban and rural areas in terms of assuming behavioral patterns of religious, political, scientific, artistic, national figures and teachers. 3-The most important criterion for selecting behavioral patterns of students is intellectual understanding with the pattern. 4-The most important factor influencing the behavioral patterns of male and female students is parents followed by friends. 5-Boys are affected by teachers, the Internet and satellite programs more than girls. Girls assume behavioral patterns from books more than boys. 6-There is a significant difference between students in human sciences, technical, medical and engineering disciplines in terms of selecting religious and political figures as behavioral patterns. 7-There is a significant difference between students belonging to different subcultures in terms of assuming behavioral patterns of religious, scientific and cultural figures. 8-Between the first and fourth year students in terms of selecting behavioral patterns, there is a significant difference only in selecting religious figures. 9-There is a significant negative correlation between the education level of parents and the selection of religious and political figures and teachers. 10-There is a significant negative correlation between family income and the selection of political and religious figures.

Keywords: behavioral patterns, behavioral patterns, male and female students, Islamic Azad University

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