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ashtari-nakhaei--aida
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Effectiveness Evaluation of Making Natural Childbirth Free of Charge on Household Decision in Choosing Delivery Method
, M.Sc. Thesis Sharif University of Technology ; Fatemi Ardestani, Farshad (Supervisor) ; Heidarzadeh, Mohammad (Co-Advisor)
Abstract
The rate of cesarean section delivery in Iran is high and during the past 14 years, leading up to 2014, kept rising. In this regard, decreasing cesarean section rate was targeted through the healthcare reform plan, which was offered by Ministry of Health and Medical Education. This plan kicked off on May4, 2014. One of the most important proceedings of this plan was making natural childbirth to be free in all hospitals, which are under the auspices of the medical universities. According to healthcare utilization models, lower prices of healthcare services, more health centers and more accessibility to them, increase the probability of using health care services. Current study evaluated the...
The effect of soil-structure interaction on damage index of buildings
, Article Engineering Structures ; Volume 30, Issue 6 , 2008 , Pages 1491-1499 ; 01410296 (ISSN) ; Ali Ghannad, M ; Sharif University of Technology
2008
Abstract
The effect of Soil-Structure Interaction (SSI) on Park and Ang Damage Index in a Bilinear-SDOF model is investigated under seismic loading. This is done through an extensive parametric study. Two non-dimensional parameters are used as the key parameters which control the severity of SSI: (1) a non-dimensional frequency as the structure-to-soil stiffness ratio index and (2) the aspect ratio of the structure. The soil beneath the structure is considered as a homogeneous elastic half space and is modeled using the concept of Cone Models. The system is then subjected to three different earthquake ground motions as the representative motions recorded on different soil conditions. The analysis is...
The effect of soil-structure interaction on hysteretic energy demand of buildings
, Article Structural Engineering and Mechanics ; Volume 24, Issue 5 , 2006 , Pages 641-645 ; 12254568 (ISSN) ; Ghannad, M. A ; Sharif University of Technology
Techno-Press
2006
Abstract
The effect of soil-structure interaction (SSI) on hysteresis energy demand of buildings using an ensemble of alluvium site records was investigated. The structure and the soil were molded separately and then combined to constitute the soil-structure model using the sub-structure method. The key parameters effecting the response of the soil-structure system were found to be a non-dimensional frequency as a representative of structure to soil stiffness ratio; and aspect ratio of the building. It was found that the hysteric energy dissipated in a structure under an earthquake can be highly effected when the stiffness of the soil beneath the structure is altered
Mechanical Design and Fabrication of a Parallel Hybrid Vehicle Powertrain Simulator
, M.Sc. Thesis Sharif University of Technology ; Saadat Foumani, Mahmoud (Supervisor)
Abstract
In this research, the mechanical section of a reduced-scale hybrid vehicle simulator was designed and fabricated. In order to scale down the vehicle dynamics, a method based on dimensional analysis was proposed. An internal combustion engine and an electric motor were selected as power sources and then, scaling was performed, according to the specifications of the combustion engine. Afterwards, the power transmission system was designed first in concept and then in more detail. Finally, the design was manufactured and assembled. The study was made in conjunction with another study responsible for the controlling section of the work, conducted by Safabakhsh The sponsor of these two researches...
Super Hydrophobic Ni Coating on Steel by Electrodeposition Method
, M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem (Supervisor)
Abstract
In this study, the properties of super-hydrophobic Ni coating on carbon steel including wetting behavior and corrosion resistance of Nickel coatings deposited on the steel substrate were investigated. For this purpose, Nickel coatings deposited by electrodeposition method in deferent current density (10,20,30,50, 70 mA /cm2) in bath containing 1.5 mol of ethylene de-ammonium de-chloride, 0.5 mol H3BO3, 1 mol Nicl2.6H2o and then immersed in a bath containing 0.01 mol per liter myristic acid and ethanol for 24 hours and then placed in the room temperature for 14 days. Deferent tests were used for characterization, wettability properties, corrosion behavior and morphology of Ni coatings. The...
A Reinforcement Learning Approach for Dynamic Pricing (Case Study: Iran Electrical Power Grid)
, M.Sc. Thesis Sharif University of Technology ; Shadrokh Sikari, Shahram (Supervisor)
Abstract
Population growth and the escalating use of electric devices have led to a surge in electricity demand. However, the construction of adequate infrastructure to meet this additional demand is highly expensive. To address this issue that sometimes causes power outages, dynamic pricing for electricity, a demand management technique, has gained significant importance. By employing this method, prices can be adjusted on an hourly basis, enabling consumers to regulate their consumption in response to these price fluctuations. The prices can be determined based on different objective functions. This research aims to develop a comprehensive framework for determining the optimal hourly electricity...
How do adsorbent orientation and direction of external electric field affect the charge-transfer surface-enhanced raman spectra?
, Article Journal of Physical Chemistry C ; Volume 125, Issue 24 , 2021 , Pages 13382-13390 ; 19327447 (ISSN) ; Jamshidi, Z ; Sharif University of Technology
American Chemical Society
2021
Abstract
Surface-enhanced Raman spectroscopy is a highly sensitive phenomenon and a powerful fingerprint detection tool that reflects the small changes in polarizability on the pattern and intensity of Raman signals. The SERS enhancement signals elucidate with the surface-selection rules. In this regard, molecular configuration and adsorption orientation on the surface, in addition to the direction of external electric field, can lead to different patterns of SERS spectra. To evaluate how the variation of these features influences the pattern and reproducibility of the spectra, the chemical charge-transfer SERS spectra for pyridine on silver clusters are calculated for different field directions,...
Evaluation of Performance of Emergency Relief Vehicles Responding to Traffic Accidents in Tehran
, M.Sc. Thesis Sharif University of Technology ; Nassiri, Habibollah (Supervisor)
Abstract
High number of traffic accidents in Iran and its rate which is well above the world's average is a major issue of concern. The results of recent researches show a direct relation between survival rate of traffic accidents' injuries and the Emergency Response Time (ERT). The main objective of this research is to analyze different aspects of ERT in Tehran, Iran and to compare these results with the International standards. This study intends to compare the selected routes by ambulance drivers with the shortest paths recommended by EMME/2. Results of analysis show that when the travel time between accident scene and the emergency dispatch center is less than 8 minutes, the possibility of...
Bootstrap-based Ensemble Clustering of Resting-state fMRI Time Series
, M.Sc. Thesis Sharif University of Technology ; Vosoughi Vahdat, Bijan (Supervisor)
Abstract
Studies in recent years have shown formation of strongly functionally linked sub-networks during rest, networks that are often referred to as resting-state networks. RSNs not only have basic information about the brain but also play a key role in detecting brain disorders, such as Alzheimer and Autism; Consequently, they have been remarkably noticed by neuroscientists. Numerous methods have been used in order to extract RSNs using resting-states fMRI time series. Independent component analysis (ICA) is the most common method, whi have been reported to show a high level of consistency neurophysiology; however, its results is unstable in subject-level. is weakness restricted the ICA...
Multi-Scale Simulation of Metallic Nano-Alloy Compression Process Using Plasticity Cone-Cap Behavior Model
, M.Sc. Thesis Sharif University of Technology ; Khoei, Amir Reza (Supervisor)
Abstract
The primary purpose of this study is to perform nonlinear behavior simulations in the compaction and forming of metal powders and their alloys and investigate their behavior in the plastic state. Powder compression is one of the methods of producing metal parts with high precision and improved mechanical properties, which is why it has been considered in addition to its need in the industry.There are various methods for performing these simulations, including multi-scale methods with optimal performance. Given that only the use of high-scale methods or only low-scale methods will have problems and disadvantages in such simulations, multi-scale methods will be a good alternative in which both...
Structural and Computational Studies of Chloro and Nitro Cobaloxime Complexes Containing Tris (p-methoxyphenyl) Phosphine Ligand
, M.Sc. Thesis Sharif University of Technology ; Kia, Reza (Supervisor)
Abstract
In this study, two new cobaloxime complexes with molecular formula [Co(DMGH)2{P(p-PhOCH3)3}(X)] in which X= Cl, NO2 were synthesized and their structure studied. These complexes were identified by FT-IR and1H-NMR 31P{1H}-NMR methods as well as their solid state structure studied by X-ray crystallography. The non-covalent interaction of two complexes including non-classical hydrogen interactions, C─H...π interactions, and dispersion interactions were confirmed and compared theoretically and experimentally by analyzing the data extracted from X-ray single crystal diffraction
Probabilistic Comparison of Sustainability of Pavement Maintenance Programs
, M.Sc. Thesis Sharif University of Technology ; Tabatabaee, Nader (Supervisor)
Abstract
With the increasing importance of the sustainable development perspective, coupled evaluation of the environmental, economic, and functional performance of pavement maintenance programs needs to be considered. This task requires the use of data and models from different sources, which introduce uncertainty in the analysis. The use of probabilistic analysis may allow decision-makers to reach more realistic conclusions. To this end, all phases of the pavement life cycle, including material production, construction, use, and salvage at the end of life, should be considered. The effect of pavement-vehicle interaction (PVI) in the operation phase has received less attention from researchers. In...
Supervised fuzzy partitioning
, Article Pattern Recognition ; Volume 97 , 2020 ; Nateghi Haredasht, F ; Beigy, H ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Centroid-based methods including k-means and fuzzy c-means are known as effective and easy-to-implement approaches to clustering purposes in many applications. However, these algorithms cannot be directly applied to supervised tasks. This paper thus presents a generative model extending the centroid-based clustering approach to be applicable to classification and regression tasks. Given an arbitrary loss function, the proposed approach, termed Supervised Fuzzy Partitioning (SFP), incorporates labels information into its objective function through a surrogate term penalizing the empirical risk. Entropy-based regularization is also employed to fuzzify the partition and to weight features,...
Efficient simulation of resonance Raman spectra with tight-binding approximations to density functional theory
, Article Journal of Chemical Physics ; Volume 157, Issue 8 , Volume 157, Issue 8 , 2022 ; 00219606 (ISSN) ; Jamshidi, Z ; Visscher, L ; Sharif University of Technology
American Institute of Physics Inc
2022
Abstract
Resonance Raman spectroscopy has long been established as one of the most sensitive techniques for detection, structure characterization, and probing the excited-state dynamics of biochemical systems. However, the analysis of resonance Raman spectra is much facilitated when measurements are accompanied by Density Functional Theory (DFT) calculations that are expensive for large biomolecules. In this work, resonance Raman spectra are therefore computed with the Density Functional Tight-Binding (DFTB) method in the time-dependent excited-state gradient approximation. To test the accuracy of the tight-binding approximations, this method is first applied to typical resonance Raman benchmark...
Discussing the Behavior of the Boundary Theory Caused by Kalb-Ramond Field Perturbation in the Bulk, Using AdS/CFT Correspondence
, M.Sc. Thesis Sharif University of Technology ; Arfaei, Hessamaddin (Supervisor)
Abstract
In this thesis we have used the low energy effective action of the string theory to find an asymptotic Anti-de sitter metric with a non-vanishing H field. Then we have used the AdS/CFT correspondence to study the effects of the added Kalb_Ramond field on two calculations in the boundary theory. The first one was the calculation of the drag force exerted on a moving quark in the quark-gluon plasma. In the second calculation we observed the effect of the added field on the confinement-de confinement phase transition
A simulated countercurrent moving bed reactor for oxidation of CO at low concentration over Pt/Al2O3
, Article Studies in Surface Science and Catalysis ; Volume 159 , 2006 , Pages 805-808 ; 01672991 (ISSN) ; Saito, Y ; Yotsumoto, T ; Kazemeini, M ; Aida, T ; Sharif University of Technology
Elsevier Inc
2006
Cost overrun risk assessment and prediction in construction projects: a bayesian network classifier approach
, Article Buildings ; Volume 12, Issue 10 , 2022 ; 20755309 (ISSN) ; Ansari, R ; Hassannayebi, E ; Jeong, J ; Sharif University of Technology
MDPI
2022
Abstract
Cost overrun risks are declared to be dynamic and interdependent. Ignoring the relationship between cost overrun risks during the risk assessment process is one of the primary reasons construction projects go over budget. Conversely, recent studies have failed to account for potential interrelationships between risk factors in their machine learning (ML) models. Additionally, the presented ML models are not interpretable. Thus, this study contributes to the entire ML process using a Bayesian network (BN) classifier model by considering the possible interactions between predictors, which are cost overrun risks, to predict cost overrun and assess cost overrun risks. Furthermore, this study...
Rutting and moisture resistance evaluation of polyethylene wax–modified asphalt mixtures
, Article Petroleum Science and Technology ; Volume 34, Issue 17-18 , 2016 , Pages 1568-1573 ; 10916466 (ISSN) ; Darbandi Olia, A. D ; Akbari Nasrekani, A ; Asadi, P ; Sharif University of Technology
Taylor and Francis Inc
2016
Abstract
One of the methods newly introduced in pavement technology to address environmental concerns and reduce total gas emission is warm mix asphalt (WMA) technology. In this study, polyethylene wax is used to produce WMA mixtures. Although this technology has several positive features, moisture and rutting resistance of WMA mixtures are always questionable. To evaluate moisture and rutting resistance of polyethylene-modified mixtures, indirect tensile strength and dynamic creep tests were used, respectively. Results indicated that polyethylene has positive effect at low compaction temperature on moisture resistance, and also has negative effect on rutting resistance
Path Simplification Game
, M.Sc. Thesis Sharif University of Technology ; Abam, Mohammad Ali (Supervisor)
Abstract
The problem of path simplification is an important problem in computer science. With the advances in navigation and geographical information based systems, simplification and data compression have gained considerable importance. The intends to find a path with less weight than the provided path while estimating the initial path with good accuracy and simplifying the storage and process cost of path information. This problem is not only useful in Geographical Information Systems, but it also has use cases in image processing and computer graphics and has been studied a lot in computational geometry. In this research, we introduce a simplification game that models the limited version of the...
The role of microstructure in mechanical behaviors of low-alloy sintered steels
, Article Scientia Iranica ; Volume 7, Issue 1 , 2000 , Pages 41-49 ; 10263098 (ISSN) ; Simchi, A ; Moradkhani, D ; Ashtari, M ; Khorsand, H ; Davami, P ; Sharif University of Technology
Sharif University of Technology
2000
Abstract
In this study, microstructural aspects that control fracture and deformation resistance of P/M materials are evaluated. Several low-alloy steels were produced under both experimental and commercial conditions for achieving different matrix phases and porosity levels with varying shape factors. A 'porosity map' was constructed and used for a quantified study of the dominant mechanism controlling mechanical behaviors. The role of inclusion gathering and secondary pores, as well as sintering mechanism and alloying method is considered and discussed. The mechanism assessment was performed by using microstructure examination through optical and scanning electron microscopy. The results...