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Future Studies of Sustainability Indicators of Iranian Supply Energy System
, M.Sc. Thesis Sharif University of Technology ; Maleki, Abbas (Supervisor)
Abstract
According to current trend of energy production and consumption in the world, economic problems in various countries and too many eco-system disorders in which created by an unsustainable trend in development, recently, the concept of “sustainability” and in the following “sustainable development” has been featured by scientists, researchers and policy makers in different scientific disciplines specially energy system engineering. Therefore exact recognition of unsustainability of local and global energy supply and demand system is very essential. In this research after selection of five energy indicators for sustainable development by Delphi and MCDM methods, future perspective of Iranian...
Evaluating the effect of non-poisson traffic patterns on power consumption of sleep mode in the IEEE 802.16e MAC
, Article 4th IEEE and IFIP International Conference on Wireless and Optical Communications Networks, WOCN 2007, Singapore, 2 July 2007 through 4 July 2007 ; 2007 ; 1424410045 (ISBN); 9781424410040 (ISBN) ; Nayebi, M. M ; Sharif University of Technology
2007
Abstract
In this paper, we study the effect of non-Poisson traffic patterns on energy consumption for IEEE 802.16e nodes while operating in the sleep mode. In the sleep mode, a Mobile Subscribe Station (MSS) sleeps for a sleep interval and wakes up at the end of this interval in order to check buffered packet(s) at Base Station (BS) destined to it. If there is no packet, the MSS increases the sleep window up to the maximum value and sleeps again. For a more general traffic pattern (rather than Poisson), we evaluate the average power consumption. Based on our analysis, we conclude that traffic pattern plays an important role in power consumption. ©2007 IEEE
Effect of different traffic patterns on power consumption of sleep mode in the IEEE 802.16e MAC
, Article 2007 IEEE International Conference on Telecommunications and Malaysia International Conference on Communications, ICT-MICC 2007, Penang, 14 May 2007 through 17 May 2007 ; February , 2007 , Pages 649-653 ; 1424410940 (ISBN); 9781424410941 (ISBN) ; Nayebi, M. M ; Ashtiani, F ; Sharif University of Technology
2007
Abstract
In this paper, we study the effect of some traffic patterns on energy consumption for IEEE 802.16e nodes while operating in the sleep mode. In the sleep mode, a Mobile Subscribe Station (MSS) sleeps for a sleep interval and wakes up at the end of this interval in order to check buffered packet(s) at Base Station (BS) destined to it. If there is no packet, the MSS increases the sleep window up to the maximum value and sleeps again. For a more general traffic pattern, we evaluate the average power consumption. Based on our analysis, we conclude that traffic pattern plays an important role in power consumption. ©2007 IEEE
Estimation of Chitgar Lake Evaporation and the Impact of Chemical Coverings on its Reduction
, M.Sc. Thesis Sharif University of Technology ; Tajrishy, Masoud (Supervisor) ; Irajizad, Azam (Supervisor)
Abstract
Reducing water evaporation is one of the ways to overcome the low precipitation and drought conditions in water reservoirs. For this purpose, extensive studies have been investigated on physical and chemical coatings on lakes and reservoirs. Physical methods often involve the use of floating covers on the water surface to block evaporation by shading, most of which are only suitable for reservoirs with surface areas smaller than 5 hectares. In chemical methods, the evaporation can be decreased by nanomaterial coating, usually, containing long-chain molecules, which by spraying them on the surface, molecular monolayers are formed. In this study, the effect of nanometer coatings on the surface...
Prediction of natural gas flow through chokes using support vector machine algorithm
, Article Journal of Natural Gas Science and Engineering ; Vol. 18, issue , 2014 , pp. 155-163 ; ISSN: 18755100 ; Kanani, M ; Arabloo, M ; Bahadori, A ; Zendehboudi, S ; Sharif University of Technology
2014
Abstract
In oil and gas fields, it is a common practice to flow liquid and gas mixtures through choke valves. In general, different types of primary valves are employed to control pressure and flow rate when the producing well directs the natural gas to the processing equipment. In this case, the valve normally is affected by elevated levels of flow (or velocity) as well as solid materials suspended in the gas phase (e.g., fine sand and other debris). Both surface and subsurface chokes may be installed to regulate flow rates and to protect the porous medium and surface facilities from unusual pressure instabilities.In this study a reliable, novel, computer based predictive model using Least-Squares...
A novel viewpoint to the green city concept based on vegetation area changes and contributions to healthy days: a case study of Mashhad, Iran
, Article Environmental Science and Pollution Research ; 2021 ; 09441344 (ISSN) ; Makian, M ; Gheibi, M ; Fathollahi Fard, A. M ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
One of the significant challenges in urbanization is the air pollution. This highlights the need of the green city concept with reconsideration of houses, factories, and traffic in a green viewpoint. The literature review confirms that this reconsideration for green space has a positive effect on the air quality of large cities and to reduce the air pollution. The purpose of this study is to evaluate the annual vegetation changes in the green space of Mashhad, Iran as a very populated city in the middle east to study the air pollution. To investigate the relationship between the air pollution and vegetation, the Landsat 8 satellite images for summer seasons of 2013–2019 were used to extract...
Power consumption evaluation of sleep mode in the IEEE 802.16e MAC with multi service connections
, Article 2007 IEEE International Conference on Signal Processing and Communications, ICSPC 2007, Dubai, 14 November 2007 through 27 November 2007 ; 2007 , Pages 1363-1366 ; 9781424412365 (ISBN) ; Nayebi, M. M ; Tadaion, A. A ; Sharif University of Technology
2007
Abstract
In the sleep mode, a Mobile Subscribe Station (MSS) sleeps for a sleep interval and wakes up at the end of this interval in order to check buffered packet(s) at Base Station (BS) destined to it. If there is no packet, the MSS increases the sleep window up to the maximum value or keeps it unchanged and sleeps again. In this paper, we study the effect of presence of multi service connections with different power saving classes (PSCs) on power consumption for IEEE 802.16e nodes while operating in the sleep mode. Using multi service connections may result in overlapping of availability and unavailability intervals and reducing the effectiveness of power saving mode of the subscriber. © 2007 IEEE...
A novel viewpoint to the green city concept based on vegetation area changes and contributions to healthy days: a case study of Mashhad, Iran
, Article Environmental Science and Pollution Research ; Volume 29, Issue 1 , 2022 , Pages 702-710 ; 09441344 (ISSN) ; Makian, M ; Gheibi, M ; Fathollahi Fard, A. M ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
One of the significant challenges in urbanization is the air pollution. This highlights the need of the green city concept with reconsideration of houses, factories, and traffic in a green viewpoint. The literature review confirms that this reconsideration for green space has a positive effect on the air quality of large cities and to reduce the air pollution. The purpose of this study is to evaluate the annual vegetation changes in the green space of Mashhad, Iran as a very populated city in the middle east to study the air pollution. To investigate the relationship between the air pollution and vegetation, the Landsat 8 satellite images for summer seasons of 2013–2019 were used to extract...
Evaporation mitigation assessment by self-assembled nano-thickness films in shallow fresh water lake using fixed and semi-floating pans
, Article Environmental Processes ; Volume 9, Issue 3 , 2022 ; 21987491 (ISSN) ; Mohammadi, M ; Doulabi, M ; Iraji zad, A ; Tajrishy, M ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
Controlling evaporation plays an essential role in arid and semi-arid water resources systems where it accounts for a considerable amount of reservoirs outflow. In this study, we have evaluated evaporation reduction efficiency of different kinds of self-assembled nano-thickness films. The films consist of six different combinations of stearyl and cetyl alcohols with additives such as jojoba oil, stearic acid, and calcium hydroxide. The study lasted from July to August and utilized two pairs of class A evaporation pans: one pair was semi-floating on Chitgar lake water surface while the other one was located on the shore. The experimental results showed that a monolayer containing 3:1 stearyl...
Repurposing the drug, ivermectin, in COVID-19: toxicological points of view
, Article European Journal of Medical Research ; Volume 27, Issue 1 , 2022 ; 09492321 (ISSN) ; Mirzaei, R ; Nakhaee, S ; Nejatian, A ; Ghafari, S ; Mehrpour, O ; Sharif University of Technology
BioMed Central Ltd
2022
Abstract
The global COVID-19 pandemic has affected the world’s population by causing changes in behavior, such as social distancing, masking, restricting people’s movement, and evaluating existing medication as potential therapies. Many pre-existing medications such as tocilizumab, ivermectin, colchicine, interferon, and steroids have been evaluated for being repurposed to use for the treatment of COVID-19. None of these agents have been effective except for steroids and, to a lesser degree, tocilizumab. Ivermectin has been one of the suggested repurposed medications which exhibit an in vitro inhibitory activity on SARS-CoV-2 replication. The most recommended dose of ivermectin for the treatment of...
Insight into the corrosion inhibition of Biebersteinia multifida root extract for carbon steel in acidic medium
, Article Science of the Total Environment ; Volume 836 , 2022 ; 00489697 (ISSN) ; Soltani, N ; Tavakkoli, N ; Nejatian, A ; Ebrahimian, J ; Mahdi, M. A ; Salavati Niasari, M ; Sharif University of Technology
Elsevier B.V
2022
Abstract
In this project, the protective effect of Biebersteinia multifida root extract (BMRE) against corrosion of 1018 low carbon steel (1018LCS) in HCl solutions was appraised by assessing weight loss, electrochemical impedance spectroscopy (EIS), and polarization at 25 °C. The maximum inhibitory efficacy for the concentration of 1 g/l of the BMRE was 92.8% at 25 °C after 2 h and increased to 95.3% after 24 h of immersion. Polarization experiments have shown that the extract in acidic solutions can act as a mixed corrosion inhibitor. The corrosion inhibitory efficacy of BMRE decreased with increasing temperature, and at all temperature settings studied, the adsorption of BMRE molecules on 1018 LCS...
Conformal invariance and quantum aspects of matter
, Article International Journal of Modern Physics A ; Volume 15, Issue 7 , 2000 , Pages 983-988 ; 0217751X (ISSN) ; Salehi, I. I ; Golshani, M ; Sharif University of Technology
2000
Abstract
The vacuum sector of the Brans-Dicke theory is studied from the viewpoint of a non-conformally invariant gravitational model. We show that, this theory can be conformally symmetrized using an appropriate conformal transformation. The resulting theory allows a particle interpretation, and suggests that the quantum aspects of matter may be geometrized
The study on resolution factors of LPBF technology for manufacturing superelastic NiTi endodontic files
, Article Materials ; Volume 15, Issue 19 , 2022 ; 19961944 (ISSN) ; Pelevin, I. A ; Karimi, F ; Shishkovsky, I. V ; Sharif University of Technology
MDPI
2022
Abstract
Laser Powder Bed Fusion (LPBF) technology is a new trend in manufacturing complex geometric structures from metals. This technology allows producing topologically optimized parts for aerospace, medical and industrial sectors where a high performance-to-weight ratio is required. Commonly the feature size for such applications is higher than 300–400 microns. However, for several possible applications of LPBF technology, for example, microfluidic devices, stents for coronary vessels, porous filters, dentistry, etc., a significant increase in the resolution is required. This work is aimed to study the resolution factors of LPBF technology for the manufacturing of superelastic instruments for...
Emergent de Sitter cosmology near black hole horizon
, Article Journal of High Energy Physics ; Volume 2022, Issue 11 , 2022 ; 10298479 (ISSN) ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
We propose an effective model for an exponentially expanding universe in the brane-world scenario. The setup consists of a 5D black hole and a brane close to the black hole horizon. In case the brane acquires a specific configuration, which we deduce from stability arguments, the induced metric outside the black hole horizon on the brane becomes de Sitter in static coordinates. Studying the Einstein equations perturbatively we find the effective gravity on the brane at this level and derive the 4D gravitational constant. Considering a homogeneous and isotropic fluid in the corresponding FLRW coordinates we find that the bulk fluid density inside the brane, which has the same equation of...
Numerical and theoretical study of performance and mechanical behavior of pem-fc using innovative channel geometrical configurations
, Article Applied Sciences (Switzerland) ; Volume 11, Issue 12 , 2021 ; 20763417 (ISSN) ; Alshukri, M. J ; Alsabery, A. I ; Hashim, I ; Sharif University of Technology
MDPI
2021
Abstract
Proton exchange membrane fuel cell (PEM-FC) aggregation pressure causes extensive strains in cell segments. The compression of each segment takes place through the cell modeling method. In addition, a very heterogeneous compressive load is produced because of the recurrent channel rib design of the dipole plates, so that while high strains are provided below the rib, the domain continues in its initial uncompressed case under the ducts approximate to it. This leads to significant spatial variations in thermal and electrical connections and contact resistances (both in rib–GDL and membrane–GDL interfaces). Variations in heat, charge, and mass transfer rates within the GDL can affect the...
Numerical and theoretical study of performance and mechanical behavior of pem-fc using innovative channel geometrical configurations
, Article Applied Sciences (Switzerland) ; Volume 11, Issue 12 , 2021 ; 20763417 (ISSN) ; Alshukri, M. J ; Alsabery, A. I ; Hashim, I ; Sharif University of Technology
MDPI
2021
Abstract
Proton exchange membrane fuel cell (PEM-FC) aggregation pressure causes extensive strains in cell segments. The compression of each segment takes place through the cell modeling method. In addition, a very heterogeneous compressive load is produced because of the recurrent channel rib design of the dipole plates, so that while high strains are provided below the rib, the domain continues in its initial uncompressed case under the ducts approximate to it. This leads to significant spatial variations in thermal and electrical connections and contact resistances (both in rib–GDL and membrane–GDL interfaces). Variations in heat, charge, and mass transfer rates within the GDL can affect the...
Predicting communication quality in construction projects: A fully-connected deep neural network approach
, Article Automation in Construction ; Volume 139 , 2022 ; 09265805 (ISSN) ; Hosseini, M. R ; Martek, I ; Taroun, A ; Alvanchi, A ; Odeh, I ; Sharif University of Technology
Elsevier B.V
2022
Abstract
Establishing high-quality communication in construction projects is essential to securing successful collaboration and maintaining understanding among project stakeholders. Indeed, poor communication results in low productivity, poor efficiency, and substandard deliverables. While high-quality communication is recognized as contingent on the interpersonal skills of workers, the impacts of communication quality on job performance remain unknown. This study addresses this deficiency by developing a method to evaluate construction workers' communication quality. A literature review is undertaken to capture salient interpersonal skills. Leadership style, listening, team building, and clarifying...
A robust multilevel segment description for multi-class object recognition
, Article Machine Vision and Applications ; Vol. 26, issue. 1 , 2014 , pp. 15-30 ; ISSN: 0932-8092 ; Gholampour, I ; Sharif University of Technology
2014
Abstract
We present an attempt to improve the performance of multi-class image segmentation systems based on a multilevel description of segments. The multi-class image segmentation system used in this paper marks the segments in an image, describes the segments via multilevel feature vectors and passes the vectors to a multi-class object classifier. The focus of this paper is on the segment description section. We first propose a robust, scale-invariant texture feature set, named directional differences (DDs). This feature is designed by investigating the flaws of conventional texture features. The advantages of DDs are justified both analytically and experimentally. We have conducted several...
Reduced memory requirement in hardware implementation of SVM classifiers
, Article ICEE 2012 - 20th Iranian Conference on Electrical Engineering, 15 May 2012 through 17 May 2012 ; May , 2012 , Pages 46-50 ; 9781467311489 (ISBN) ; Gholampour, I ; Sharif University of Technology
2012
Abstract
Support Vector Machine (SVM) is a powerful machine-learning tool for pattern recognition, decision making and classification. SVM classifiers outperform other classification technologies in many applications. In this paper, two implementations of SVM classifiers are presented using Logarithmic Number System. In the basic classifier all operations (multiplication, addition and ...) are performed using logarithmic numbers. In the logarithmic domain, multiplication and division can be simply treated as addition or subtraction respectively. The main disadvantage of LNS is the large memory requirement for high precision addition and subtraction. In the improved classifier, multiplication...
Optimization of supercritical carbon dioxide extraction of essential oil from spearmint (Mentha spicata L.) leaves by using Taguchi methodology
, Article Journal of Supercritical Fluids ; Volume 67 , July , 2012 , Pages 123-130 ; 08968446 (ISSN) ; Goodarznia, I ; Sharif University of Technology
2012
Abstract
In this study, the essential oil of aerial parts species of a plant called Spearmint was extracted by CO 2 to optimize the results of the supercritical extraction process. In order to achieve maximum total yield extraction and SF-CO 2 concentration, tests were done in a laboratorial pilot considering the Taguchi method under following condition: pressure. 90,100,140,170 bar, temperature. of 35, 40, 45, 50 °C, mean particles size: 250,500,710,1000 μm, flow rate 1,3,5,8 ml/s and dynamic time 30,50,90,120 min. The optimizing conditions for SCE and SF-CO 2 concentration are: 90 bar, 45 °C, 500 μm, 5 ml/s, 120 min and 90 bar, 35 °C, 250 μm, 1 ml/s, 30 min. SCE total yield and CO 2 concentration...