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environmental-conditions
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Cold-Briquetted iron and carbon (CBIC): investigation of the influence of environmental condition on its chemical and physical properties
, Article Journal of Sustainable Metallurgy ; Volume 5, Issue 4 , 2019 , Pages 497-509 ; 21993823 (ISSN) ; Askari, M ; Shahahmadi, S. A ; Sharif University of Technology
Springer
2019
Abstract
In this study, a comprehensive investigation was carried out on the effects of environmental condition on physical and chemical properties of Cold-Briquetted Iron and Carbon (CBIC), Cold Direct Reduced Iron (CDRI), and Hot-Briquetted Iron (HBI). The results showed that cold briquetting of CDRI decreases its specific surface area by 51%, which has a significant effect on its oxidation resistance and mechanical strength. Microscopic observations revealed that the oxidation products are formed in near-surface porosities during aging, which protects the fresh material underneath from environmental oxidants, resulting in retarding further oxidation. The oxidation behavior of the samples showed...
Evaluating the Effect of Crumb Rubber as a Binder Modifier on Bonding Properties of Chip Seal Against Environmental Effect
, M.Sc. Thesis Sharif University of Technology ; Motamed, Arash (Supervisor)
Abstract
Crumb Rubber is one of the main polymer modifiers of binders. This modifier can improve chip seal performance against ravelling (aggregate loss). The most concerning distress in chip seal is ravelling. Aggregate loss is not restricted to the early life of chip seal, but continues throughout the service life. Chip seal can be made with hot binders or emulsion binders. These two type of binder were modified with 7% and 15% of crumb rubber in applicable way. Then, two major environmental effect on chip seal performance, freeze-thaw and asphalt aging, were investigeted based on laboratory test. For this purpose, authors used chip seal bonding test. Chip seal bonding test is developed recently...
Reliability Evaluation of Heat Recovery Steam Generator of Combined Cycle Thermal Power Plants
, M.Sc. Thesis Sharif University of Technology ; Saeedi, Mohammad Hassan (Supervisor) ; Kazemzadeh Hannani, Siamak (Supervisor)
Abstract
Combined cycle power plants consist of three main sections, namely gas turbine, Heat Recovery Steam Generator (HRSG) and steam turbine. Occurring failure in HRSG causes the steam turbine trip, so the reliability assessment of HRSG has a great importance for forecasting the probability of occurring failure and also reducing failure causes. In this project, the reliability of HRSG considering effects of aging phenomenon, maintenance and, environmental and operational conditions on reliability is modeled. Afterward a method to estimate the model parameters is introduced. Using present method, failure data of six HRSGs of a plant each with a capacity of 50 MW is analyzed and the model parameters...
Study of Environmental Conditions, Fuel Type and Turbocharging in Thermodynamic Simulation of a Wankel Engine
, M.Sc. Thesis Sharif University of Technology ; Morad, Mohammad Reza (Supervisor)
Abstract
Since the construction of the first models of internal combustion engines in the nineteenth century, efficiency and, since the late twentieth century, pollution and fuel consumption has been the main issue for researchers and manufacturers who have always sought to improve it. Manufacturers of internal combustion engines are required to perform numerous tests to carefully study and increase the level of technology and reliability of their products. There have been two ways for them to do this; the first way is to use the experimental method; that is, making multiple samples that require a high cost that makes it impossible. The second way is to use engine simulation software, which can be...
Weighing criteria and prioritizing strategies to reduce motorcycle-related injuries using combination of fuzzy topsis and ahp methods
, Article Advances in Transportation Studies ; Volume 54 , 2021 , Pages 217-234 ; 18245463 (ISSN) ; Safaei, N ; Masoud, A ; Seyedekrami, S ; Sharif University of Technology
Aracne Editrice
2021
Abstract
Unsafe driving behavior and hazardous environmental conditions lead lo traffic crashes and injuries. The annual rale of road crashes in Iran is twenty times higher than the world's average. Motorcycle crashes have higher fatality rates than other motor vehicle crashes, and they exert psychological pressure on the communities and have adverse economic consequences for the societies. This paper analyzes Tehran's motorcycle crash data and investigates the effective underlying factors. Seven strategies were presented and prioritized to reduce the number and severity of motorcycle crashes. The fuzzy Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) combined with the...
COACH: Consistency aware check-pointing for nonvolatile processor in energy harvesting systems
, Article IEEE Transactions on Emerging Topics in Computing ; Volume 9, Issue 4 , December , 2021 , Pages 2076-2088 ; 21686750 (ISSN) ; Hosseini Monazzah, A. M ; Bazzaz, M ; Safaei, B ; Ejlali, A ; Sharif University of Technology
IEEE Computer Society
2021
Abstract
Recently, energy harvesting systems that utilize hybrid NVM-SRAM memory in their designs are introduced as a promising alternative for battery-operated systems. Since the ambient input power of an energy harvesting system fluctuates as the environmental conditions change, the system may stop the execution of programs until it receives enough energy to continue the execution. Resuming the execution of a program after the suspension may lead to data inconsistency in an energy harvesting system and threatens the correct functionality of the programs. In this article, we propose COACH, an energy-efficient consistency-aware memory scheme which guarantees the correct functionality and consistency...
Experimental Study on Mooring System of Offshore Wind Turbines
, M.Sc. Thesis Sharif University of Technology ; Abbaspour Tehrani Fard, Majid (Supervisor)
Abstract
Limited fossil resources, daily increase of demand for energy and the most important one that is environmental pollution fact, make people think of renewable energy as a solution. One type of these renewable energies is offshore wind energy that has high potential without any sound and visual noises. Recently a lot of researches have carried out their studies on the topic of offshore wind turbine. Cause of disabling of a lot of software to simulating of dynamic effect of rotating rotors, so in this research has make effort to fabricate and test an offshore wind turbine with different rotor rotating velocities and different heading angle of wind, to catch the effect of these parameter on the...
Boundary control of a marine riser pipe conveying fluid
, Article ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE) ; Vol. 4A , 2014 ; ISBN: 9780791846476 ; Shirazi, M. J ; Salarieh, H ; Sharif University of Technology
Abstract
In this paper, the model of pipe conveying fluid, like marine risers, is modeled with the effect of the interaction between the fluid and structure. A torque is assumed at one end of the pipe to control the vibration of the pipe. The stability of the pipe under time varying disturbance in forced vibration using boundary control law is proved. Exponential stability can be achieved under the free vibration condition. The proposed control law is simple and could be attained by some simple sensors at the end of the pipe. The control law is independent from system parameters so the controller is robust to disturbances and environmental conditions. The controller is obtained via a Lyapunov...
Design methodology and preliminary sizing of an unmanned mars exploration plane (UMEP)
, Article APPLIED MECHANICS AND MATERIALS; 332; 15; Biomechanics, neurorehabilitation, mechanical engineering, manufacturing systems, robotics and aerospace: optimization of the engineering systems; OPTIROB 2013 ; Volume 332 , 2013 , Pages 15-20 ; 16609336 (ISSN) ; 9783037857335 (ISBN) ; Banazadeh, A ; Golkhandan, A. R ; Sharif University of Technology
2013
Abstract
This paper discusses the mission requirements and design constraints for an Unmanned Martian research aircraft based on a tailor-made classical airplane design methodology. First, the exploration mission is described using the information from previous real-world experiences and the desired payload is proposed accordingly. The environmental conditions that dictate severe constraints to the design space are characterized afterwards. The conventional airplane design cycle is modified to address the lack of statistical data and to define a proper design recycling criteria. Eventually, the outcome is presented in the form of a novel configuration that is well suited to carry out the specified...
Investigating the effects of quadrature error in parametrically and harmonically excited MEMS rate gyroscopes
, Article Measurement: Journal of the International Measurement Confederation ; Volume 87 , 2016 , Pages 152-175 ; 02632241 (ISSN) ; Salarieh, H ; Sharif University of Technology
Elsevier B.V
2016
Abstract
Some factors like environmental conditions and manufacturing errors affect performance of a MEMS rate gyroscope. Because they may result to parameter mismatch between the designed gyroscope and the fabricated one. The Parametrically excited gyros are more robust to these changes than the harmonically excited gyros. However, these types of gyros also experience reduction in their accuracy in angular velocity determination due to these changes. One of parameters that affect the accuracy of the gyroscope is quadrature error that here, its effect in the accuracy of angular velocity determination is investigated in two typically designed harmonically and parametrically excited MEMS gyroscopes....
An integrated SPH-polyhedral DEM algorithm to investigate hydraulic stability of rock and concrete blocks: application to cubic armours in breakwaters
, Article Engineering Analysis with Boundary Elements ; Volume 84 , 2017 , Pages 1-18 ; 09557997 (ISSN) ; Pak, A ; Sharif University of Technology
Abstract
In this paper, a combination of the Lagrangian meshfree method of SPH and Polyhedral DEM is presented to simulate the interaction between the free surface of water and solid objects possessing sharp edges and flat surfaces, such as armour units of breakwaters. Both SPH and DEM schemes are validated successfully against experimental data. The numerical scheme is utilized to inspect the stability of concrete cubic armours in rubble-mound breakwaters through systematic analyses with various geometrical parameters and environmental conditions. The numerical results regarding the required dimensions of the cubic blocks for providing stability of the armour units under the wave attack are compared...
Experiments and probabilistic models of bond strength between GFRP bar and different types of concrete under aggressive environments
, Article Construction and Building Materials ; Volume 148 , 2017 , Pages 429-443 ; 09500618 (ISSN) ; Ashrafi, H ; Vatani Oskouei, A ; Sharif University of Technology
Abstract
Bond durability of FRP bars and concrete is an important issue to the overall integrity and long-term performance of a strengthening structure. This paper examines the bond durability of GFRP bars embedded in different types of concrete (Normal, self-compacting, light weight, and high strength) exposed to aggressive environments, namely, sea water, alkaline, and acid. A total of 132 specimens were tested in direct pull-out. The development lengths of both control and conditioned specimens were obtained and compared to the current standards. The results revealed bond strength reductions of 0–21% for the light weight, 1–16% for the normal, 5–9% for the high strength, and 4–12% for the...
Airborne turbines: The impact of scaling on system performance
, Article ASME 2017 International Mechanical Engineering Congress and Exposition, IMECE 2017, 3 November 2017 through 9 November 2017 ; Volume 6 , 2017 ; 9780791858417 (ISBN) ; Goudarzi, N ; ASME ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
2017
Abstract
Tethered airborne wind energy systems are among emerging renewable energy technologies in recent years. These systems can harness greater power densities at higher altitudes with lower costs of installation and energy production in comparison with those from conventional ground-based energy harnessing technologies. A Buoyant Airborne Turbine (BAT) as a flying aerostat has a horizontal axis wind turbine within its shell and can elevate up to 600m. There are a number of pertinent parameters such as BAT configurations/component dimensions or its aerodynamic characteristics that impact the system total power performance. Identifying the optimum values of these parameters by conducting...
Effects of linear acceleration in a harmonically excited proof mass MEMS rate gyroscope
, Article Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science ; Volume 232, Issue 19 , 2018 , Pages 3551-3563 ; 09544062 (ISSN) ; Salarieh, H ; Sharif University of Technology
SAGE Publications Ltd
2018
Abstract
MEMS rate gyroscopes are prone to different errors because of environmental conditions and manufacturing errors. These errors can result to mismatch between the fabricated gyros and the designed ones. Different environmental conditions and disturbances can change the parameters and specifications of a gyro, and its sensitivity may deteriorate, since the parameters are different from the optimal ones. External linear acceleration is one of the main environmental disturbances that may change the behavior of an MEMS rate gyro that its effect on the accuracy of an MEMS proof mass gyroscope is found here. This is done by finding the equations of motion of gyroscope in presence of acceleration and...
A Nested Logit analysis of the influence of distraction on types of vehicle crashes
, Article European Transport Research Review ; Volume 10, Issue 2 , 2018 ; 18670717 (ISSN) ; Mahmoudzadeh, A ; Kermanshah, M ; Sharif University of Technology
Springer Verlag
2018
Abstract
Purpose: This work aims to study factors, such as driver characteristics, environmental conditions, and vehicle characteristics, that affect different crash types with a special focus on distraction parameters. For this purpose, distraction factors are divided into five groups: cellphone usage, cognitive distractions, passengers distracting the driver, outside events attracting the driver’s attention, and in-vehicle activities. Methods: Taking the crashes that occurred in the USA into account, the crash types are divided into two main groups, single-vehicle crashes and two-vehicle crashes. Since there were different crash types (alternatives) in the dataset and the probable correlation in...
COACH: Consistency aware check-pointing for nonvolatile processor in energy harvesting systems
, Article IEEE Transactions on Emerging Topics in Computing ; 2019 ; 21686750 (ISSN) ; Hosseini Hosseini Monazzah, A. M ; Bazzaz, M ; Safaei, B ; Ejlali, A ; Sharif University of Technology
IEEE Computer Society
2019
Abstract
Recently, energy harvesting systems that utilize hybrid NVM-SRAM memory in their designs are introduced as a promising alternative for battery-operated systems. Since the ambient input power of an energy harvesting system fluctuates as the environmental conditions change, the system may stop the execution of programs until it receives enough energy to continue the execution. Resuming the execution of a program after the suspension may lead to data inconsistency in an energy harvesting system and threatens the correct functionality of the programs. In this paper, we propose COACH, an energy-efficient consistency-aware memory scheme which guarantees the correct functionality and consistency of...
COACH: Consistency aware check-pointing for nonvolatile processor in energy harvesting systems
, Article IEEE Transactions on Emerging Topics in Computing ; 2019 ; 21686750 (ISSN) ; Hosseini Monazzah, A. M. H ; Bazzaz, M ; Safaei, B ; Ejlali, A ; Sharif University of Technology
IEEE Computer Society
2019
Abstract
Recently, energy harvesting systems that utilize hybrid NVM-SRAM memory in their designs are introduced as a promising alternative for battery-operated systems. Since the ambient input power of an energy harvesting system fluctuates as the environmental conditions change, the system may stop the execution of programs until it receives enough energy to continue the execution. Resuming the execution of a program after the suspension may lead to data inconsistency in an energy harvesting system and threatens the correct functionality of the programs. In this paper, we propose COACH, an energy-efficient consistency-aware memory scheme which guarantees the correct functionality and consistency of...
Practical approaches for implementation of energy piles in Iran based on the lessons learned from the developed countries experiences
, Article Renewable and Sustainable Energy Reviews ; Volume 140 , 2021 ; 13640321 (ISSN) ; Ghasemi Fare, O ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Ground Source Heat Pumps (GSHPs) have been installed all around the world to harvest shallow geothermal energy for heating and cooling building envelopes. However, the high initial cost of these systems (e.g., drilling and installation costs) limits the popularity and total usage of GSHPs around the world. To reduce the initial cost of these systems, geothermal heat exchangers are combined with structural components of the building, such as deep foundations, or energy walls. Energy piles or thermo-active foundations that serve dual purposes have been widely utilized in the last two decades in many developed countries. However, in most of the developing countries like Iran, there are several...
Effect of environmental conditions on fracture behavior of solder joints
, Article Theoretical and Applied Fracture Mechanics ; Volume 112 , 2021 ; 01678442 (ISSN) ; Nourani, A ; Karimi, M ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Double cantilever beam (DCB) specimens were prepared according to standard surface mount technology (SMT). The samples were stored inside an environmental chamber at two different relative humidity values (i.e. 40 or 100%) for either 2 or 4 h. Then they were aged at 25 °C, 75 °C or 125℃ for the same time. Finally, after being cooled to room temperature, fracture tests were performed under mode-I loading conditions at a strain rate of 0.03 s−1 at room temperature. Storage time did not have a significant effect on the fracture behavior. The fracture load and energy of the solder joints decreased significantly when the temperature was increased from 25 to 75℃. By further increase in the...
Use of the freely-swimming, Serratia marcescens bacteria to enhance mixing in microfluidic systems
, Article ASME 2009 International Mechanical Engineering Congress and Exposition, 13 November 2009 through 19 November 2009 ; Volume 12, Issue PART A , 2010 , Pages 463-467 ; 9780791843857 (ISBN) ; Shafii, M. B ; Rasoulian, R ; Jamalifar, H ; Fazeli, M. R ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
Abstract
Mixing has become a challenge in micro-fluidic systems because of the low Reynolds number in micro-channels. The method which is implemented in this paper is to use freely-swimming bacteria to enhance the mixing process. Accordingly, the Serratia marcescens bacteria were used for this matter. The mixing performance of the system is quantified by measuring the diffusion rate of Rhodamine B in a particular section of a channel connected to a chamber with varying Rhodamine B concentration. The concentration of Rhodamine B was measured using the Laser Induced Fluorescence (LIF) technique. The channel is in the form of a pipe and is closed on the extending side. In this paper, it is demonstrated...