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Evaluation of performance-based mix design for asphalt mixtures containing Reclaimed Asphalt Pavement (RAP)
, Article Construction and Building Materials ; Volume 235 , 2020 ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
In this research, the possibility of producing asphalt mixtures containing Reclaimed Asphalt Pavement (RAP) that perform well from both fatigue and rutting points of view was studied. For this, seven asphalt mixtures with varying RAP percentage and total binder content were produced. All other variables, including the gradation and binder type, were kept constant. To better control for the production variables, the mixtures were produced in the laboratory. Fatigue and rutting properties of the mixtures were evaluated using the Simplified Viscoelastic Continuum Damage (S-VECD) model and Triaxial Stress Sweep (TSS) test, respectively. Next, FlexPAVETM software was utilized to predict the...
An investigation on perpetual asphalt pavements in Minnesota
, Article International Journal of Pavement Research and Technology ; Volume 13, Issue 3 , 2020 , Pages 247-254 ; Sharif University of Technology
Springer
2020
Abstract
Asphalt Pavement Alliance (APA) created the Perpetual Pavement Award program in 2001. This program requires that the roadway has at least 35 years of service at the time of award and had experienced no structural failures. In addition, the program limits candidate roadways to those that have not received more than 100 mm of new asphalt nor have been resurfaced at a frequency exceeding 13 years. Minnesota Department of Transportation (MnDOT) currently owns the record for the most award winners and has received an award every year from 2002 through 2017. This study reviews all the award-winning roadways in Minnesota to determine common material, design factors and considerations which may have...
Numerical study of species separation in rarefied gas mixture flow through micronozzles using DSMC
, Article Physics of Fluids ; Volume 31, Issue 4 , 2019 ; 10706631 (ISSN) ; Darbandi, M ; Sharif University of Technology
American Institute of Physics Inc
2019
Abstract
This work investigates the species separation in the rarefied flow of the argon-helium mixture through convergent-divergent micronozzles. Imposing a molecular mass ratio in the order of 10, the flow of this mixture can lead to the formation of serious nonhomogeneous phenomena such as the species separation. This study is performed in the ranges of 2.0-4.0 for the geometrical expansion ratio, 200-400 K for the wall temperature, and 0.003-1.454 for the inlet Knudsen number. The effects of these parameters are examined on the separative performances of micronozzle. The direct simulation Monte Carlo method is selected as the solution method because it can provide reliable solutions in the...
SUT-Crack: A comprehensive dataset for pavement crack detection across all methods
, Article Data in Brief ; Volume 51 , 2023 ; 23523409 (ISSN) ; Sepidbar, A ; Sharif University of Technology
Elsevier Inc
2023
Abstract
The SUT-Crack dataset (Sharif University of Technology Crack Dataset) presents a collection of high-quality images depicting asphalt pavement cracks specifically designed to facilitate crack detection using various deep learning methods, including classification, object detection, segmentation, etc. During the dataset creation process, careful consideration was given to encompass all possible crack detection challenges, such as the presence of oil stains and shadows on the pavement surface along with varying lighting conditions. The dataset comprises 130 images designed specifically for segmentation and object detection tasks. Each image is accompanied by precise ground truth annotations....
Hybrid method: automatic crack detection of asphalt pavement images using learning-based and density-based techniques
, Article International Journal of Pavement Research and Technology ; 2023 ; 19966814 (ISSN) ; Mohammadi, M ; Sharif University of Technology
Springer
2023
Abstract
Pavement distress is a major contributor to overall road quality degradation. Maintaining roadways with the use of a Pavement Management System requires an extensive and up-to-date inventory of the many types of roadway distress. Such inventory for a road network can be labor-intensive and time-consuming to create. This study introduces a novel method, called Hybrid Method, to detect asphalt pavement surface cracks based on 2D images. Hybrid Method consists of two separate techniques, proposed by this study, which are combined to detect cracks. The first is a supervised learning-based technique which requires annotated images. This approach utilizes the Local Binary Pattern (LBP) as a...
Tax Incidence; Evidence from Iran’s VAT
, M.Sc. Thesis Sharif University of Technology ; Vesal, Mohammad (Supervisor)
Abstract
In this paper we determine “Tax Incidence” of value added tax (VAT). Incidence Tax represents tax burden that is imposed to each tax-payers: consumers or producers. Value added tax was first implemented in Iran in Mehr 1387. Providing a natural experiment condition, it made it possible to measure tax incidence by using difference-in-difference method. Therefore, data of monthly consumer price index of 23 tax-exempt commodities, and 23 taxable commodities, have been used from Farvardin 1384 till Esfand 1393. According to the results, from 1387 to 1390, no tax incidence regarding value added tax was found. It seems, in the first years of implementation, it is the result of its resemblance with...
Liquefaction Effects on (a) Individual and Group of Capless Piles and (b) Group of three Piles under Real and Artificial Earthquakes
, M.Sc. Thesis Sharif University of Technology ; Haeri, Mohsen (Supervisor)
Abstract
In the areas where the soil beneath the foundation is made of loose to semi-consolidated sand or noncohesive silts, Buildings and bridges are usually built on the pile foundations. One important issue that must be considered in the design of piles in saturated sandy soils, is liquefaction potential of saturated sandy soil under earthquake loads. During the earthquake, saturated sandy soil faces the sudden loss of shear strength in other word it liquifies . Liquefied Soil acts like a viscous fluid. This behaviour considerably increases the soil deformation and consequently the widespread disruption of soil layers, causes large deformation and applies great amount of forces on the piles...
A Feasibility Study in Fuel Cell Hydrogen Storage Capacity Increase Using Carbon Nanotubes Technology and Molecular Dynamics Simulation
, M.Sc. Thesis Sharif University of Technology ; Darbandi, Masoud (Supervisor)
Abstract
Hydrogen fuel cell is one important choice to supply energy for vehicles in near future. The lack of a safe but inexpensive technology to store hydrogen in a vehicle tank is a serious challenge to commercialize the application of fuel cells. Past experiments have shown that carbon nanostructures, especially single walled carbon nanotubes, have considerable capacity to boost up hydrogen storage. Therefore, many studies have been performed to investigate the possibility of higher hydrogen storage capability using nanostructures for the past decade. Molecular dynamics method which is considered as one of the most important tools in studying nanostructures has shown vast applications in these...
Developing a Hybrid Continuum-Molecular Method to Analyze Binary Gas Mixing and Separation Processes
, Ph.D. Dissertation Sharif University of Technology ; Darbandi, Masoud (Supervisor)
Abstract
The co-existance of rarefied and near-continuum flow regimes is widelyencountered in analyzing the multiscale flow problems, e.g., micro-and nanoflows. Previous investigations have revealed that the continuum-based simulation methods would suffer from the lack of accuracy to predict the rarefied flow regimes. On the other hand, the molecular simulation methods are not computationally efficient in simulating the near-continuum flow regimes. Therefore, the use of hybrid simulation methods has been recommended as a serious alternative to simulate the multiscale flow problems. These methods apply the molecular methods in solving the rarefied flow regions and the continuum methods in solving the...
Separation of Employment and Production, and Capital Intensive Iranian Economy
, M.Sc. Thesis Sharif University of Technology ; Nili, Masoud (Supervisor)
Abstract
In the Iranian economy, the unemployment rate has always been volatile and double-digit, and this has had a devastating effect on people's livelihoods and the welfare of society. Therefore, job creation has always been the main concern of policymakers. To increase employment, based on the Okun's law, the output must be increased. Since from an economic point of view, economic growth should be accompanied by employment growth and there should be a positive relationship between the employment growth rate and the country's economic growth rate. But in 1384 to 1398, the Iranian labor market has experienced a puzzling behavior in terms of the growth of the total number of employees and the growth...
Effectiveness of linear amplitude sweep (LAS) asphalt binder test in predicting asphalt mixtures fatigue performance
, Article Construction and Building Materials ; Volume 171 , May , 2018 , Pages 281-290 ; 09500618 (ISSN) ; Mirzaeian, D ; Moniri, A ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
In this research, Linear Amplitude Sweep (LAS) test was conducted on several asphalt binders modified by different percentages of gilsonite and Styrene-Butadiene-Styrene (SBS) polymer. Asphalt mixtures were also made from some of the study binders and tested for fatigue resistance using Four-point Bending Beam (FBB) fatigue test. The results showed that a strong correlation exists between LAS and FBB rankings at all the tested strain levels. Also, SHRP binder fatigue index (G∗sinδ), as a traditional binder fatigue index, was evaluated which did not show a strong correlation with either LAS or FBB tests. It was concluded that LAS test seems to be an effective binder fatigue test in predicting...
Crack Detection on Asphalt Concrete Pavements Using Image Processing
,
M.Sc. Thesis
Sharif University of Technology
;
Sabouri, Mohammad Reza
(Supervisor)
Abstract
Road transportation has long been an important form of transportation for mankind. Mass production of motorized vehicles and a growing number of people using human and goods transportation have led engineers to monitor road pavement condition and to act on accordingly in the case of degradation. Due to road networks expansion and budget restrictions, road pavement maintenance and rehabilitation projects should be prioritized based on up-to-date data. Automatic collection of data related to the pavement condition such as the number and the length of cracks, could save time and reduce cost and workforce. This research proposes a hybrid method composed of two independent techniques for...
Investigation of the Effect of Fibers on the Performance of Cold Recycled Asphalt Mixtures
, M.Sc. Thesis Sharif University of Technology ; Sabouri, Mohammad Reza (Supervisor)
Abstract
Despite major environmental and economic benefits of cold recycled asphalt mixtures, many agencies have not yet made widespread use of this technology due to its so-called poor field performance and lack of accurate information on mechanical properties of cold recycled mixtures. Fiber is one the additives that is sometimes used to enhance asphalt mixture properties. Using fibers to improve the performance of cold recycled asphalt mixture has been studied by a few researchers with somehow contradictory results. In this research, the effects of adding four synthetic fibers (Polypropylene, A-glass, Para-Aramid, and Polyester) and two waste fibers (Waste Polyester and Waste Nylon) with different...
Performance Evaluation of Cold-Recycled Mixtures
, M.Sc. Thesis Sharif University of Technology ; Sabouri, Mohammad Reza (Supervisor)
Abstract
This study aims to investigate the mechanical properties and performance of cold recycled asphalt mixtures (CRM). So far, several methods have been proposed for designing CRMs, which are mostly based on the volumetric and mechanical properties of the mixtures. In the meantime, few researches have considered performance of those mixes. The main approach of current research is to evaluate and enhance performance characteristics of CRMs regarding common distresses including early-raveling, moisture damage, fatigue cracking by an appropriate additive.Raveling and Cantabro tests were employed to evaluate the resistance of CRM against abrasion and semicircular bending test (SCB) and crack tolerate...
Crack Detection of Asphalt Concrete Pavements Based on Deep Learning
, M.Sc. Thesis Sharif University of Technology ; Sabouri, Mohammad Reza (Supervisor)
Abstract
The health of the pavement ensures the safety and convenience of drivers and passengers. In the past few decades, pavement management systems have encountered challenges that often have produced solutions with excessive demand for resources, but low-accuracy results. New approaches must be developed in order to quickly and economically identify pavement failure, especially cracks. In recent years, researchers have focused on identifying pavement failures, but previous methods only worked on images that solely included pavements and cracks. However, when foreign objects such as cars and vegetation were present, these methods were not as effective. To improve upon these methods, semantic...
Optimal Control of Spacecraft on the Earth-Moon Lagrange Point Orbits considering Sun and other Planets and Elliptic Orbit Perturbations
, M.Sc. Thesis Sharif University of Technology ; Assadian, Nima (Supervisor)
Abstract
In this thesis, optimal station keeping of spacecraft on the closed-orbits near the Earth-Moon Lagrange points has been investigated. Lagrange points L1 and L2 are unstable equilibrium points of the circular restricted three-body problem (CRTBP), and periodic orbits near them are the destination of modern missions. However, perturbations resulting from the gravitational forces of the Sun and the planets and the eccentricity of the orbit of the Moon around the Earth make the Lagrange point unstable, even L4 and L5, which are stable in CRTBP. The most suitable choice for spacecraft mission near the collinear Lagrange points is the Halo and other closed-orbits around them, which need...
Orbit Design and Optimization of Satellite Constellation for Regional Coverage
, M.Sc. Thesis Sharif University of Technology ; Assadian, Nima (Supervisor)
Abstract
In this thesis, the satellite constellation orbit design for regional coverage is investigated. The orbits of satellites in a constellation for Earth observation missions play a crucial role in performance and characteristics of the mission; for example the image resolution, the area of coverage, and the coverage interval. In this thesis the problem is to find the optimal initial orbital elements for meeting the earth observation mission objectives for one or several sites. The cost functions are the total coverage time, the maximum gap time, time average gap, altitude, and number of satellites. The problem is solved in a multi-objective manner for different combination of two of the above...
Autonomous Orbit Estimation for Regional Navigation Satellites
, M.Sc. Thesis Sharif University of Technology ; Asadian, Nima (Supervisor)
Abstract
In this thesis, autonomous orbit estimation of regional navigation satellites has been investigated. Estimation of satellite orbit is an integral part of satellite navigation, which may be executed via assistance of ground station. As the satellite is exposed to the ground station view, range, direction and rate of range is measured by mean of ranging instrumentation relative to ground reference, hence the precise position is calculated. In this thesis a set of satellites are investigated in a unique structure called constellation with the purpose of navigation. The occurrence which is likely to happen in this condition, is the failure of ground station under certain circumstances or losing...
Fabrication and Characterization of a UF Ceramic Membrane based on TiO_2 Nanoparticles
, M.Sc. Thesis Sharif University of Technology ; Taghavinia, Nima (Supervisor)
Abstract
UF membranes are widely used in various industries now, a major type of these membranes are ceramic membranes which are resistant to high temperatures and corrosive fluids. In this thesis we developed an anisotropic UF ceramic membrane based on 20nm TiO2 nanoparticles on a prous sustrate. We had two major challenges, the first one was to find a suitable prous substrate and the second one was to find an appropriate coating method. Our main task was to optimise the process conditions to achive a crackless and uniform membrane layer with minimal ups and downs. Lots of coating methods and TiO2 inks have been tried, finally we used a coating method which we called it “Soft Blade Coating”, with...
Continuous-thrust Trajectory Optimization in the Binary Asteroids System
, M.Sc. Thesis Sharif University of Technology ; Asadian, Nima (Supervisor)
Abstract
In this thesis, the optimal trajectories of a spacecraft in the binary asteroids system is studied. The objective functions of optimal trajectories in these system are the maximum coverage of the asteroids surface and minimum time and fuel consumption. For this purpose, the dynamic of binary system is modeled. The binary system of 1999 KW4 is selected as a case study. The ellipsoid-sphere model is a good approximation for the case of this study. In this model, the asteroids orbit in a circular orbit around each other in a spin-spin-orbit resonance configuration, in which the asteroids’ rotational velocity is equal to orbital mean motion. Then, the equations of motion of the spacecraft as the...