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bastami--dariush
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The Effect of Type, Size and Morphology of Nanoparticles on the Hydrodynamics of Rising Bubble Motion
, M.Sc. Thesis Sharif University of Technology ; Bastani, Dariush (Supervisor) ; Feizi, Pouyan (Co-Supervisor)
Abstract
The motion of gas bubbles in the bulk of a fluid can be one of the most widely used industrial phenomena. Various factors such as the size and shape of the bubbles, the physical properties of the liquid phase such as density and viscosity, method of gas injection, the presence of impurities, etc. affect this phenomenon. Some of the most important industrial processes that include the motion of bubbles in the liquid phase bulk are gas adsorption, distillation and froth flotation. According to the results of previous studies, the hydrodynamics of bubble motion in the bulk of a liquid fluid depends on the presence of impurities such as surfactants, proteins and colloidal particles. In many...
Rolling Element Bearing Fault Diagnosis and Prognosis
, Ph.D. Dissertation Sharif University of Technology ; Behzad, Mehdi (Supervisor)
Abstract
Diagnostic and prognostic of spall defect in the rolling element bearings is investigated in this thesis. A new numerical model is proposed which considers defect size, defect clearance and defect roughness. The results of this model based on surface roughness show superior similarity to experimental data than classic model. To improve diagnostic ability in the rolling element bearings, four new methods are proposed in this thesis. These methods are short-time statistical features, local curve roughness, level crossing and wavelet packet decomposition. These methods are applied in outer ring, inner ring and ball defects and it is showed that these methods have better detection ability...
RDC Column Performance Prediction Using Axial Dispersion Model for Continuous and Forward Mixing Model for Dispersed Phase
, M.Sc. Thesis Sharif University of Technology ; Bastani, Dariush (Supervisor)
Abstract
In this project, the continuous phase mass transfer and backflow coefficients are optimized, using the experimental data from two RDC columns. The continuous and dispersed phases are modeled by stage wise and forward mixing model, respectively. Genetic Algorithm is applied to find the optimized parameters of the model. Olney model is employed to find the slip velocities of drops. The dispersed phase mass transfer coefficients were calculated using Handlos-Baron model. In the other part of the project, the Rigid Drop model was modified to predict the mass transfer coefficients of dispersed phase and the modification parameter was optimized by genetic algorithm. The effect of rotor speed and...
Separation of CO2 from CO2-air Mixture Using ILM Membrane Containing TEG-DEA
, M.Sc. Thesis Sharif University of Technology ; Bastani, Dariush (Supervisor)
Abstract
CO2 separation from air was investigated in this work. An immobilized liquid membrane (ILM) which contains triethylene glycol (TEG) and diethanolamine (DEA) was used for this purpose. In this kind of membranes a liquid, which improves permeability of gas species through the membrane, fills the pores of a polymeric membrane as support. Because of low vapor pressure of solution, liquid loss was negligible. Transport of CO2 was facilitated due to reversible chemical reaction between CO2 and amine solution. A polyvinylidene fluoride (PVDF) membrane was chosen to have chemical resistance against the solution and prevent destruction of polymer by solution. A flat sheet and hydrophilic PVDF was...
Separation of Carbondioxide from CO2-Air Mixture Using ILM Membrane Containg DGA-TEG
, M.Sc. Thesis Sharif University of Technology ; Bastani, Dariush (Supervisor)
Abstract
In this research, initially the Triethylene glycol and Diglycol amine liquid membrane which is supported by PVDF, was prepared in order to separate the Carbone dioxide from CO2-Air mixture. A polyvinylidene fluoride (PVDF) membrane was chosen to have chemical resistance to solution. The effect of Pressure, Concentration of TEG and DGA solution and the percentage of carbon dioxide in feed; in rate and permeability of CO2, N2 and O2 and also selectivity of CO2/ N2 , CO2/ O2 and N2/ O2 was investigated. Transport of CO2 was facilitated due to reversible chemical reaction between CO2 and amine solution. The experiments were done in 0.4, 0.6 and 0.8bar and different concentration of solution....
Oxygen Enrichment of Air by Membrane Technology to Reduce Energy Consumption
, M.Sc. Thesis Sharif University of Technology ; Bastani, Dariush (Supervisor)
Abstract
In various industries, for energy production, fossil fuels are burned. Oxygen needed for combustion, taken directly from the ambient air; So that the inert gas is about 80%. The presence of this inert gas, mainly nitrogen, reduce combustion efficiency and increase the use of combustible material. In this project with the help of membrane technology, was used to remove the amount of nitrogen in the air so that the incoming air into the combustion chamber is enriched with oxygen. For this purpose, several gas separation membrane was applied and evaluated. Then, according to the oxygen enrichment, fuel efficiency and the amount of savings, increasing chamber temperature, reduction manufacturing...
Study and Modeling of CHP Systems in Power Plant
, M.Sc. Thesis Sharif University of Technology ; Bastani, Dariush (Supervisor)
Abstract
In the present study, a heat recovery system for a distributed generation plant (DG) with a 1 MW gas combustion engine has been designed. The purpose of this designing is converting the power plant to a CHP system. For the existing heat recovery system, a shell & tube heat exchanger is designed to recover the thermal energy from exhaust gases and a plate heat exchanger is designed to recover the thermal energy from the engine jacket cooling fluid. The heat exchanger design has been calculated manually and also by use of software. In the software calculation, the heat exchanger design has been done by use of the Aspen HTFS +2006.5 software. In the manual one, the Kern equation (1950) was...
Investigation of Mass Transfer in Liquid-Liquid System in the Presence of Nanosized Particles
, M.Sc. Thesis Sharif University of Technology ; Bastani, Dariush (Supervisor)
Abstract
The main objective of this project is to study the effect of the presence of nanoparticles on mass transfer in liquid-liquid systems. To do this research, TiO2/water, Al2O3/water, CNTs/water and CNTs/toluene have been used as nanofluids. The experiments of TiO2/water nanofluid were been carried out in water-acetone-toluene system at two weigh percents of TiO2 nanoparticles. The result showed that mass transfer decreased in 0.5wt% of TiO2, compared to base fluid, and it increase in 1 %wt. Also in 0.5%wt the decrease in interfacial tension decreased diameter of drops and as a result mass transfer decreased too. In 1%wt the increase in viscosity increased the diameter of drops and then the...
Prognostics of rolling element bearings with the combination of Paris law and reliability method
, Article 2017 Prognostics and System Health Management Conference, PHM-Harbin 2017 - Proceedings, 9 July 2017 through 12 July 2017 ; 2017 ; 9781538603703 (ISBN) ; Addin Arghan, H ; Rohani Bastami, A ; Sharif University of Technology
2017
Abstract
In this research, a combination of the physical model based on Paris law and probability method is proposed for remaining useful life prediction of rolling element bearings. Level crossing is used as a feature that represents a linear relationship with defect size. Considering this linear relationship and using Paris law, a new model has been developed for bearings that follow degradation pattern with two stages. In this pattern, a bearing starts working in the healthy condition. Then it starts slow degradation stage and finally it goes to fast degradation stage until it reaches to the failure threshold. Considering a normal distribution for transition point from the slow degradation to the...
Estimation of remaining useful life of rolling element bearings using wavelet packet decomposition and artificial neural network
, Article Iranian Journal of Science and Technology - Transactions of Electrical Engineering ; Volume 43 , 2019 , Pages 233-245 ; 22286179 (ISSN) ; Aasi, A ; Arghand, H. A ; Sharif University of Technology
Springer International Publishing
2019
Abstract
Rolling element bearings (REBs) are usually considered among the most critical elements of rotating machines. Therefore, accurate prediction of remaining useful life (RUL) of REBs is a fundamental challenge to improve reliability of the machines. Vibration condition monitoring is the most popular method used for diagnosis of REBs and this is a motivating fact to use recorded vibration data in RUL prediction too. However, it is necessary to extract appropriate features from vibration signal that represent actual damage progress in the REB. In this paper, wavelet packet transform is used to extract signal features and artificial neural network is applied to estimate RUL of the REB. To obtain...
Remaining useful life prediction of ball-bearings based on high-frequency vibration features
, Article Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science ; Volume 232, Issue 18 , 2018 , Pages 3224-3234 ; 09544062 (ISSN) ; Arghand, H. A ; Rohani Bastami, A ; Sharif University of Technology
SAGE Publications Ltd
2018
Abstract
Selecting appropriate features from the vibration condition monitoring data of ball-bearings is one of the main challenges in the application of data-driven methods for remaining useful life prediction purpose. In this article, a new feature based on the high-frequency vibration of ball-bearings is proposed. The feed forward neural network will be used for training and prediction. The experimental data of the bearing accelerated life in the PROGNOSTIA test (published in PHM 2012 IEEE conference) are used to verify the method. The results obtained by applying new features are compared with those of two popular features in the time domain (RMS and kurtosis) for prognostic purpose. Applying the...
The Role of E-WOM Social Commerce And Subjective Norms On Online Impulsive Buying
, M.Sc. Thesis Sharif University of Technology ; Khalili Nasr, Arash (Supervisor)
Abstract
One challenge in the world of digital business is the impact of opinion leaders on the type of e-commerce shopping. In this research, emotional shopping is specifically investigated, and to examine the effect of opinion leaders, this research that compares the impact of mental norms and word-of-mouth advertising has addressed the word of mouth of the online trading world on emotional shopping. In this study, I applied the S-O-R model (stimulus-organism-response model) to discuss subjective norms and word-of-mouth advertising in the online trading world as stimuli and, according to this model, organisms of satisfaction and trust, hedonic browsing, and utilitarian browsing are examined, and...
The Study of Nanoparticles on the Droplets Hydrodynamics
, M.Sc. Thesis Sharif University of Technology ; Bastani, Dariush (Supervisor)
Abstract
Liquid-liquid extraction is one of the common chemical processes in the industry which its application is increasing day by day. Taking trend of increase of energy resources, chemical materials and industrial system into account, the necessity use of least energy consumption and material for achieving highest output and purity of products in different industries is attracted researches and industerialists.In this research we have studied the effect of presence of nano particles on both disperses and continuous liquids phases on hydrodynamic of deoplets specially their investigated system in this project was watter, toluene and acetone, and chosen nanoparticles wer carbon nanotubes and TiO2....
Rapid removal of heavy metal ions from aqueous solutions by low cost adsorbents
, Article International Journal of Global Environmental Issues ; Volume 12, Issue 2-4 , 2012 , Pages 318-331 ; 14666650 (ISSN) ; Rohani Bastami, T ; Tahmasbi, M ; Zabihi, M ; Sharif University of Technology
Interscience
2012
Abstract
In the present investigation, different agricultural solid wastes namely: eggplant hull (EH), almond green hull (AGH), and walnut shell (WS), that are introduced as low cost adsorbents, were used for the removal of heavy metals (cobalt, strontium and mercury ions) from aqueous solutions. Activation process and/or chemical treatments using H 2O 2 and NH 3 were performed on these raw materials to increase their adsorption performances. The effectiveness of these adsorbents was studied in batch adsorption mode under a variety of experimental conditions such as: different chemical treatments, various amounts of adsorbents, initial metal-ion concentrations, pH of solutions, contact times, and...
Synthesis and application of diethanolamine-functionalized polystyrene as a new sorbent for the removal of p-toluenesulfonic acid from aqueous solution
, Article Journal of Industrial and Engineering Chemistry ; Volume 30 , October , 2015 , Pages 281-288 ; 1226086X (ISSN) ; Ahmadpour, A ; Rohani Bastami, T ; Dabir, H ; Sharif University of Technology
Korean Society of Industrial Engineering Chemistry
2015
Abstract
Polystyrene resin was functionalized by diethanolamine for the efficient removal of p-toluenesulfonic acid (p-TSA) from aqueous solution. Functionalized adsorbent (DEA-PS) was characterized by elemental analysis, Fourier transform infrared spectroscopy, point of zero charge measurement and field-emission scanning electron microscopy. According to the results, maximum removal of p-TSA was observed at the pH range of 2.5-5. The adsorption kinetics of p-TSA onto DEA-PS was represented by pseudo-first-order model and the equilibrium data followed Langmuir model well. The adsorption process was endothermic and spontaneous, along with the positive change of entropy. The regeneration of DEA-PS was...
Initial tests on a rolling element bearing with built-in vibration sensor for condition monitoring
, Article 17th International Congress on Sound and Vibration 2010, ICSV 2010, 18 July 2010 through 22 July 2010, Cairo ; Volume 2 , 2010 , Pages 1315-1322 ; 9781617822551 (ISBN) ; Beheshtkar, N ; Bastami, A. R ; Hale, J. M ; Sharif University of Technology
2010
Abstract
This paper presents a novel modification to a conventional rolling element bearing that allows it to monitor its own condition, and describes some preliminary tests on a prototype. The self monitoring feature is a thick-film vibration sensor deposited in a shallow groove around the outer race of the bearing. This has the virtue of being very close to the source of the impacts that are characteristic of a damaged bearing, as well as being robust and low cost. The form of the sensor is such that the loading surfaces of the outer race are only slightly modified and the bearing can be fitted into any conventional bearing housing with only minor modification to make electrical connection to the...
Outage-Constrained robust and secure design for downlink rate-splitting UAV networks
, Article 2021 IEEE International Conference on Communications Workshops, ICC Workshops 2021, 14 June 2021 through 23 June 2021 ; 2021 ; 9781728194417 (ISBN) ; Moradikia, M ; Letafati, M ; Abdelhadi, A ; Behroozi, H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
Unmanned aerial vehicles (UAVs) are developing rapidly owing to flexible deployment and access services as the air base stations. In this paper, by taking the realistic assumption of imperfect channel state information at transmitter (CSIT), we investigate the robust and secure design of downlink UAV network while considering the worst-case outage constraints due to communication link uncertainties. In our proposed heterogeneous network, comprised of both UAV-cells and macro-users, rate splitting technique is deployed by UAV base-station (UAV-BS) to enhance the system performance in terms of security, power saving, and robustness against imperfect CSIT. Through our proposed design, we...
Fast and robust LRSD-Based sar/isar imaging and decomposition
, Article IEEE Transactions on Geoscience and Remote Sensing ; Volume 60 , 2022 ; 01962892 (ISSN) ; Moradikia, M ; Bastami, H ; Abdelhadi, A ; Soltanalian, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
The earlier works in the context of low-rank-sparse-decomposition (LRSD)-driven stationary synthetic aperture radar (SAR) imaging have shown significant improvement in the reconstruction-decomposition process. Neither of the proposed frameworks, however, can achieve satisfactory performance when facing a platform residual phase error (PRPE) arising from the instability of airborne platforms. More importantly, in spite of the significance of real-time processing requirements in remote sensing applications, these prior works have only focused on enhancing the quality of the formed image, not reducing the computational burden. To address these two concerns, this article presents a fast and...
Integration of Population Balance Method and Computational Fluid Dynamics for Simulation of Bubble Column Hydrodynamics
, Ph.D. Dissertation Sharif University of Technology ; Bastani, Dariush (Supervisor) ; Sarrafi, Amir (Supervisor)
Abstract
Different modeling and simulation techniques, new numerical methods and analyzing effects of different parameters on operation of bubble columns are continuously under study for optimized design, scale-up and prediction of industrial bubble columns. Tools for analyzing and developing gas-liquid systems are experimental techniques and computational fluid dynamics (CFD). In order to describe accurately the fluid dynamics of complex gas-liquid systems, more advanced mathematical models are required. To obtain a feasible numerical solution, efficient numerical techniques must be devised. One of such models that considerably reduces the assumptions and consequently increases the accuracy of...
Preparation a Polymeric Membrane for Dehydration of Acetic Acid
, M.Sc. Thesis Sharif University of Technology ; Mousavi, Abbas (Supervisor) ; Bastani, Dariush (Supervisor)
Abstract
The separation ofacetic acids in binary water solutions hasbeenstudied using a reverse osmosis (RO) membrane. Thin film composite polyamide membrane is used in this study.Thin-film composite (TFC) membrane was prepared through the interfacial polymerization between m-phenylenediamine (MPD) and trimesoyl chloride (TMC) on the polysulphone support membrane.The solute permeation was carried out under applied pressure of 5 bar at 25°C. In this work the effect of various synthesis conditions on the membrane performance was investigated. Parametric studies were conducted by varyingconcentration of reactants, reaction time, curing time and curing temperature. By suitable combination of these...