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The Effect of Gas-oil Contamination on Geomechanical Properties of Sandy Clay Soils
, M.Sc. Thesis Sharif University of Technology ; Sedghiani, Mohammad Hossein (Supervisor)
Abstract
During recent years, decay, fraction, corrosion and leakage of oil pipe lines have resulted in soil pollution. Gas oil is one of the main causes of soil pollution in different places. Soil and pollutant interaction results in varying soil geotechnical properties which causes shear strength, permeability, etc. to change drastically. After careful recognition of the problem, it should be encountered in a good manner. Therefore, comprehensive investigation regarding the effect of oil production on soil should be done. In this thesis, properties of combination of sand, kaolinite and pollutant in different situation such as different fine grain content, different relative compaction, and...
Exprimental Study of Various Modes of Electrospray for Different Nozzles
, M.Sc. Thesis Sharif University of Technology ; Morad, Mohammad Reza (Supervisor)
Abstract
Electrospray is an interesting method to produce spray. This study has an insight on electrospraying phenomenon and its effective parameters. All modes, the forces and the situation to establish has been investigated for ethanol. Suitable configuration is introduced and for different flow rates and voltages the phenomenon is studied. Images are captured by two camera (high speed camera and high resolution camera) by using two method (shadowgraphy and light scattering). In the respect of producing fine and monodisperse droplets in cone-jet mode the stability of this mode is imported to enlarge. The special nozzle is design to increase stability of cone-jet mode even 70 times of using...
A Very stable high throughput taylor cone-jet in electrohydrodynamics
, Article Scientific Reports ; Volume 6 , 2016 ; 20452322 (ISSN) ; Rajabi, A ; Razavi, M ; Pejman Sereshkeh, S. R ; Sharif University of Technology
Nature Publishing Group
2016
Abstract
A stable capillary liquid jet formed by an electric field is an important physical phenomenon for formation of controllable small droplets, power generation and chemical reactions, printing and patterning, and chemical-biological investigations. In electrohydrodynamics, the well-known Taylor cone-jet has a stability margin within a certain range of the liquid flow rate (Q) and the applied voltage (V). Here, we introduce a simple mechanism to greatly extend the Taylor cone-jet stability margin and produce a very high throughput. For an ethanol cone-jet emitting from a simple nozzle, the stability margin is obtained within 1 kV for low flow rates, decaying with flow rate up to 2 ml/h. By...
Improving the Efficiency of On-chip 3D Stacked DRAM in Server Processors
, M.Sc. Thesis Sharif University of Technology ; Sarbazi-Azad, Hamid (Supervisor) ; Lotfi Kamran, Pejman (Co-Advisor)
Abstract
Big-data server workloads have vast datasets, and hence, frequently access off-chip memory for data. Consequently, server workloads lose significant performance potential due to off-chip latency and bandwidth walls. Recent research advocates using 3D stacked DRAM to break the walls. As 3D stacked DRAM cannot accommodate the whole datasets of server workloads, most proposals use 3D DRAM as a large cache. Unfortunately, a large DRAM cache imposes latency overhead due to (1) the need for tag lookup and (2) inefficient utilization of on-chip and off-chip bandwidth, and as a result, lowers the benefits of 3D stacked DRAM. Moreover, storing the tags of a multi-gigabyte DRAM cache requires changes...
Designing Instruction Prefetcher with Low Area Overhead for Server Workloads
,
M.Sc. Thesis
Sharif University of Technology
;
Sarbazi Azad, Hamid
(Supervisor)
;
Lotfi Kamran, Pejman
(Co-Supervisor)
Abstract
L1 instruction cache misses creates a crucial performance bottleneck for server applications. Server applications extensively use operating system services, and as such, have large instruction footprint that dwarfs instruction cache size. Meanwhile, fast access requirements preclude enlarging instruction cache that can hold the whole instruction footprint of current server workloads. Prior works proposed using hardware prefetching schemes to eliminate or reduce the effect of instruction cache misses. They use the fact that server application instruction sequences are repetitive. So by recording and prefetching based on such sequesnces, L1 insruction misses could be reduced. While they...
Simulation and Study of Iso-Dose Curve for Asymmetrical Balloon in Balloon-Brachytherapy with Cs-131
, M.Sc. Thesis Sharif University of Technology ; Hosseini, Abolfazl (Supervisor) ; Shirmardi, Pejman (Supervisor)
Abstract
Incidence of brain metastases (BM) from any tumor varies according to the method of data collection and date reported, ranging from 8 to 14 per 100,000 people per year. According to current population, about 6400 to 11000 BM Patients per year is expected. Without treatment, prognosis is dismal with survival of only 1–2 months. However, survival can be extended to 3–6 months with whole-brain radiotherapy (WBRT) and to 11 months with either surgery followed by adjuvant WBRT or surgery plus adjuvant stereotactic radiosurgery (SRS). Intravascular brachytherapy (generally iodine-125 (125I)) into the surgical cavity is another treatment strategy. 125I has been shown to confer local control...
Prediction of shear strength parameters of hydrocarbon contaminated sand based on machine learning methods
, Article Georisk ; 2020 ; Mojtahedi, S. F. F ; Taherabadi, E ; Soleymani, K ; Pejman, M ; Sharif University of Technology
Taylor and Francis Ltd
2020
Abstract
The objective of this paper is to predict the effect of hydrocarbon contamination on the shear strength parameters of sand by using various machine learning platforms. Multilayer perceptron, support vector machine, random forest, gradient boosting method, and multi-output support vector machine were methods used to predict the hydrocarbon contamination impacts on the internal friction angle and cohesion of contaminated sand. Random forest exhibited the best results for cohesion, whereas, for the friction angle, the gradient boosting method outperformed other approaches. Moreover, the multi-output support vector machine yielded better results than those pertaining to a single support vector...
Speculative Path Setup for Fast Data Delivery in Server Processors
, M.Sc. Thesis Sharif University of Technology ; Sarbazi-Azad, Hamid (Supervisor) ; Lotfi-Kamran, Pejman (Co-Advisor)
Abstract
Server workloads operate on large volumes of data. As a result, processors executing these workloads encounter frequent L1-D misses. An L1-D miss causes a request packet to be sent to an LLC slice and a response packet to be sent back to the L1-D, which results in high overhead. While prior work targeted response packets, this work focuses on accelerating the request packets through a simple-yet-effective predictor. Upon the occurrence of an L1-D miss, the predictor identifies the LLC slice that will serve the next L1-D miss and a circuit will be set up for the upcoming miss request to accelerate its transmission. When the upcoming miss occurs, the resulting request can use the already...
Liquid jet trajectory and droplet path influenced by combined cross flow and electric fields
, Article Chemical Engineering Science ; Volume 181 , 18 May , 2018 , Pages 114-121 ; 00092509 (ISSN) ; Morad, M. R ; Rahbari, N ; Pejman Sereshkeh, S. R ; Razavi, M ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
This study investigates an ethanol liquid jet subjected to combination of an air crossflow and a normal electric field. The results on the liquid jet trajectory and subsequent droplets flight paths are presented. The liquid jet trajectory was found as a function of two non-dimensional quantities; the liquid jet to the crossflow momentum ratio and the electroinertial number. The electroinertial number is defined as the ratio between the liquid jet specific momentum and the electric force. A correlation is introduced for the jet trajectory in low crossflow speeds and electric field intensities. The same two quantities control the detached droplets flight paths. Satellite droplets flight angles...
LED nanosecond pulsed imaging for electrohydrodynamic liquid breakup of a modified nozzle
, Article Experimental Thermal and Fluid Science ; Volume 98 , 2018 , Pages 546-556 ; 08941777 (ISSN) ; Morad, M. R ; Rajabi, A ; Nasiri, H ; Pejman, S. R ; Razavi Haeri, S. A. A ; Javadi, E ; Sharif University of Technology
Elsevier Inc
2018
Abstract
The behavior of an electrified liquid jet breakup and modes of disintegration were investigated at different flow rates and voltages. The current phenomenology belongs to a new injector introduced recently by Morad et al. (2016). This injector has proven to highly extend the stability and flow rate of electrospray particularly in the Taylor cone-jet mode. The experimental investigation was performed using a high-power light-emitting diode (LED) illumination as the light source. The light source was developed to operate in the pulsing condition when synchronized with a digital camera and was particularly designed to function properly in the presence of high electromagnetic interference (EMI)....