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Control of Unstable Delayed Multivariable Systems
, M.Sc. Thesis Sharif University of Technology ; Shahrokhi, Mohammad (Supervisor)
Abstract
Existence of time delay and interactions of control loops make control of multivariable delayed systems more difficult، therefore control of these systems is important. In this project a control scheme based on prediction of process output has been proposed. Traditional PI controllers are used in the control structure and controller parameters are tuned by genetic algorithm. Unlike the Smith predictor based methods، which become internally unstable when applied to unstable plants، unstable delayed multivariable systems can be handled by proposed method. It can also be applied to stochastic systems. The robust version of the control scheme has also been designed. Effectiveness of the proposed...
Synthesis of highly porous nanocrystalline alumina as a robust catalyst for dehydration of methanol to dimethyl ether
, Article Journal of Porous Materials ; Volume 20, Issue 1 , 2013 , Pages 151-157 ; 13802224 (ISSN) ; Kazemeini, M ; Aghaziarati, M ; Alamolhoda, S ; Sharif University of Technology
2013
Abstract
Highly porous nanocrystalline alumina was synthesized using two different precipitation processes and precipitating agents, which were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and porosimetry analyses. Different precipitating agents yielded nanocrystalline alumina catalysts with different morphologies and textural properties. Batch precipitation using sodium bicarbonate at constant pH resulted in a highly porous nanocrystalline γ-alumina catalyst, having surface area of 351.47 m2 g-1, total pore volume of 1.68 cm3 g -1 and mean pore diameter of 19.17 nm. The mean crystallite size was also determined to be 3.8 nm, based on the XRD results. Catalytic...
Reaction kinetics determination and neural networks modeling of methanol dehydration over nano γ-Al 2O 3 catalyst
, Article Journal of Industrial and Engineering Chemistry ; Volume 18, Issue 6 , 2012 , Pages 2059-2068 ; 1226086X (ISSN) ; Kazemeini, M ; Zaherian, A ; Zakerinasab, M. R ; Sharif University of Technology
2012
Abstract
In this research nano γ-Al 2O 3 catalyst was synthesized through precipitation process then characterized and utilized for methanol dehydration reaction in a slurry batch reactor in route to the indirect synthesis of the dimethyl ether (DME). In this venue, effects of the key parameters on methanol conversion and catalyst stability were investigated. Moreover, the internal and external mass transfer resistances were eliminated; hence the intrinsic kinetics controlled the reaction. Therefore, the optimum conditions for temperature, methanol concentration, catalyst mass and stirrer speed were determined to be 300°C, 1.18mol/l, 1.5g and 1100rpm, respectively. Next, different reaction rate...
Capability of TiO2(B)-based Nanotubes to Adsorb Lithium Ion from Aqueous Solution
, M.Sc. Thesis Sharif University of Technology ; Askari, Masoud (Supervisor) ; Alamolhoda, Ali Asghar (Supervisor)
Abstract
Due to the technology advancement and the large-scale application of lithium-ion batteries in recent years, the market demand for lithium is growing rapidly and the availability of land lithium resources is decreasing significantly. As such, the focus of lithium extraction technologies has shifted to water lithium resources. Among various aqueous recovery technologies, the lithium ion-sieve (LIS) technology is considered the most promising one. This is because LISs are excellent adsorbents with high lithium uptake capacity, superior lithium selectivity, and good cycle performance. TiO2-based nanotubes are an appropriate option for adsorbing lithium from solution due to their high specific...
Reverse osmosis desalination for irrigation in a pistachio orchard
, Article Desalination ; Volume 516 , 2021 ; 00119164 (ISSN) ; Afzali, M ; Farhadi, F ; Alamolhoda, A. A ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Nowadays, the salinisation of groundwaters causes a substantial reduction in the yield of agricultural lands. To reduce the impact of this problem on the profitability of the lands, farmers tend to use desalination processes. However, this transition is not simple and some technical, economic, and environmental issues should be considered. In this study, we highlight some key factors for the use of desalination processes in the agricultural sector. Also, we conduct a techno-economic evaluation of using reverse osmosis desalination in a pistachio orchard as a high-value crop. Moreover, because of the solar energy potential in the location of the case study, the use of solar panels is assessed...
Synthesis and characterization of salep sulfate and its utilization in preparation of heavy metal ion adsorbent
, Article Journal of Applied Polymer Science ; Volume 130, Issue 4 , 2013 , Pages 3001-3008 ; 00218995 (ISSN) ; Doulabi, M ; Alamolhoda, A. A ; Tavakkoli, E ; Amirshekari, S ; Sharif University of Technology
2013
Abstract
A multicomponent polysaccharide obtained from dried tubers of certain natural terrestrial orchids was chemically modified by sulfonation using chlorosulfonic acid-dimethylformamide (HClSO3-DMF) complex as a reagent. For a structural characterization of salep sulfate 1H nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR) spectra, and Thermogravimetric analysis (TGA) curves were recorded. The sulfate content of modified salep was determined using elemental analysis. This modified biopolymer was used to prepare a new environment-friendly heavy metal ion adsorbent, salep sulfate-graft-polyacrylic acid hydrogel (SS-g-PAA). Swelling rate and equilibrium water absorbency in various...
Febrication of Superhydrophobic Nanocomposites Containing Modified Silica Nanoparticles and Silicone Polymers and Evaluation of Their Application
, M.Sc. Thesis Sharif University of Technology ; Pourjavadi, Ali (Supervisor) ; Alamolhoda, Ali Asghar (Supervisor)
Abstract
Rehabilitation usually involves physical therapy, occupational therapy and counseling for the patient's morale to help to restore his power and performance. Considering the economic outlook and the costs of rehabilitation methods and due to the increasing prevalence of stroke and the need to recover the patients in a short period, only the use of robotic systems opens the door to the medical community. Since a large rehabilitation robots designed and built and each been used according to their advantages and shortcomings. In this project, the major shortcomings examined and exoskeleton designed on two major features including portability and covering shoulder workspace. Shoulder movement was...
A feasibility study of solar-powered reverse osmosis processes
, Article Desalination ; 2020 ; Shirvani, H ; Alamolhoda, A. A ; Farhadi, F ; Karimi, M ; Sharif University of Technology
Elsevier B.V
2020
Abstract
The use of solar-powered reverse osmosis desalination systems is a sustainable and environmentally friendly solution in the desalination industry. However, there are some substantial technical and economic challenges due to the intermittency and fluctuation of solar energy. Recent technological improvement and feed-in tariff policies enable these systems to be competitive with conventional grid-connected reverse osmosis systems. In this paper, a feasibility study of the integration of solar panels with the grid to power small-scale reverse osmosis systems (namely up to 2000 m3/day) is conducted in Iran, as a country with a low price of electricity. For this purpose, a city located on the...
A feasibility study of solar-powered reverse osmosis processes
, Article Desalination ; Volume 500 , 2021 ; 00119164 (ISSN) ; Shirvani, H ; Alamolhoda, A. A ; Farhadi, F ; Karimi, M ; Sharif University of Technology
Elsevier B.V
2021
Abstract
The use of solar-powered reverse osmosis desalination systems is a sustainable and environmentally friendly solution in the desalination industry. However, there are some substantial technical and economic challenges due to the intermittency and fluctuation of solar energy. Recent technological improvement and feed-in tariff policies enable these systems to be competitive with conventional grid-connected reverse osmosis systems. In this paper, a feasibility study of the integration of solar panels with the grid to power small-scale reverse osmosis systems (namely up to 2000 m3/day) is conducted in Iran, as a country with a low price of electricity. For this purpose, a city located on the...
Surveying the jagorood river's self-purification
, Article 6th International Conference on Environmental Informatics, ISEIS 2007 ; 21-23 November , 2014 ; Mirzai, M ; Sajadi, S. A. A ; Alamolhoda, A. A ; Sharif University of Technology
2014
Abstract
the development and enlargement of city structure has caused the environmental problems on watershed of Latian dam which is one of the drinking water resourses of Tehran. The enlargement of Lavasan town and existence of an army garrison that it's effluents of treatment plant discharge to this river necessitate a water quality surveillance in entrance area of the dam. The present research includes the survey of this river's self-purification in the mentioned-above area. Numerical analysis is used in different methods to explain self- purification. Frist, we have the numerical analysis and analytical methods for a known sample in order to determine the accuracy and deviation between two...
Lithium Extraction from Urmia Lake Brines
, M.Sc. Thesis Sharif University of Technology ; Askari, Masoud (Supervisor) ; Alamolhoda, Ali Asghar (Supervisor)
Abstract
Using a Lithium Selective Ion Sieve is one of the most advanced processes for Extraction of lithium from Brines. The ability to Extract Lithium selectively from brines make the ion sieve suitable for brines with low concentrations of lithium. In this study brines samples from Urmia Lake with lithium concentration of 30 ppm was used. The main objective of this study was to find the best condition for lithium adsorption and desorption using the synthesized titanium dioxide ion sieve. In this study lithium selective ion sieve with nanotube morphology and Diameter of 81 nm was synthesized. Study on pH of synthesized solution containing lithium ions was carried out and pH=12 was concluded the...
An industrial application of low-grade sensible waste heat driven seawater desalination: a case study
, Article Desalination ; Volume 470 , 2019 ; 00119164 (ISSN) ; Marvi, Z ; Alamolhoda, A. A ; Abbaspour, M ; Chua, H. T ; Sharif University of Technology
Elsevier B.V
2019
Abstract
This paper reports on the application of low-grade sensible waste heat (liquid phase) driven multi-effect distillation (MED) technology to exploit waste heat sources that are generally abundant in the petrochemical industries especially, those located close to the Persian Gulf's coastline. For this purpose, a techno-economic feasibility study by considering local capital and operating costs for a selected petrochemical plant has been conducted. In this study, a sensible waste heat stream (practically at 80 °C in the liquid phase), which is actively cooled by the cooling process of the plant, is considered as the heat source for the proposed desalination process. This process can recover...
Kinetics Study and Determining an Optimum Reactor Condition for Dimethyl-ether Synthesis by Dehydration of Methanol over Nano-Crystalline γ-Al2O3
,
M.Sc. Thesis
Sharif University of Technology
;
Kazemeini , Mohammad
(Supervisor)
;
Khorashe, Farhad
(Supervisor)
;
Khandan, Nahid
(Supervisor)
Abstract
Dimethyl Ether (DME) is a pure and economic fuel which can be used as a suitable alternative for diesel fuels. Two processes are traditionally used for DME synthesis: producing methanol from synthesis gas and then dehydrating it to DME (direct process), and converting methanol into DME in a catalytic dehydration reactor over a solid-acid catalyst (indirect process), in which the indirect process seems to have economical advantage. In this research, the γ-Al2O3 catalyst was synthesized through precipitation process and then characterized by powder X-ray diffraction (XRD) and porosimetry analysis. Afterwards this catalyst was utilized in methanol dehydration reaction in a slurry reactor. Next,...
Monitoring & Optimizing of the Returned Condensated Water as Boiler Make up Water at the Agro-Industry Hakim Farabi Boilers
, M.Sc. Thesis Sharif University of Technology ; Alamolhoda, Ali Asghar (Supervisor) ; Pourjavadi, Ali (Co-Advisor)
Abstract
Vapor in agro-industry hakim farabi production electricity, Turbines force and thermal energy for Yellow and white sugar in sugar production. In the utilization to supply water for the boiler , condensate water return use Until plant be able to do its work ¬good quality of condensate water decrease cost of destruction energy in blow down and can save energy, reduce cost of chemical operation for optimum boiler water and costs associated with wastewater treatment. unclean condensate water consist of sugar and Electrical conductivity more than permissive is not suitable for use in The boiler because Increase the total dissolved solids and decreasing pH lower than the Extent permitted. The...
Chemical Investigation of Molasses and Reducing Sugar Wastes of Molasses in Hakim Farabi Sugar Factory
, M.Sc. Thesis Sharif University of Technology ; Alamolhoda, Ali Asghar (Supervisor) ; Matloubi Moghaddam, Firouz (Supervisor)
Abstract
Sugar extraction from cane sugar is based on crystallization. Sucrose crystallization is a mass transfer process. Sucrose molecule's migration from solution to crystal is driven by concentration difference between the mother liquor and the crystal surface; the coefficient of super saturation is the most important parameter for the process. It has large influence on product quantity and quality (crystal yield, crystal size and size distribution). In this project, first the efficiency of sucrose extraction studied by crystallization in HAKIM FARABI sugar factory. Crystal size distribution (CSD) is the more accurate measure for monitoring crystallization processes. CSD depending on the seeds...
Synthesis of Magnetic Adsorbent Nanocomposites based on Modified Sugarcane Bagasse and Iron Nanoparticle for dye Removal from Aqueous Solutions
, M.Sc. Thesis Sharif University of Technology ; Pourjavadi, Ali (Supervisor) ; Alamolhoda, Ali Asghar (Supervisor)
Abstract
Lately, a wide application of eco-friendly polysaccharide-based hydrogels in waste water treatment has received enormous attention in the literature. The effluents containing dye materials from the processing industries are washed off into rivers and lakes which can be very harmful to creatures. Low-cost biopolymers and biodegradable adsorbents have been researched to be a good tool to minimize the environmental hazards caused by the industrial effluents by removal of these toxic and carcinogenic dyes from the waste effluents. In this study, an eco-friendly superabsorbent hydrogel was prepared by using of sugarcane bagasse, two hydrophilic monomers, magnetic nanoparticle and methylene...
Plasmon enhanced photocatalytic activity of Au@TiO2-graphene nanocomposite under visible light for degradation of pollutants
, Article Materials Research Bulletin ; Volume 87 , 2017 , Pages 40-47 ; 00255408 (ISSN) ; Hashemian, S. J ; Alamolhoda, A. A ; Gocheva, I ; Rahman Setayesh, S ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
Au@TiO2-Graphene (GR) nanocomposite was prepared using photocatalytic reduction method. TiO2-GR nanocomposite was synthesized under UV irradiation of deaerated ethanolic suspension of TiO2. The nanocomposite was calcined at 400∘C followed by loading of highly dispersed Au nanoparticles throughout the deposition-precipitation method. The Au@TiO2/GR was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, diffuse reflectance spectroscopy, transmission electron microscope and the BET surface area measurements. It was found that Au-TiO2-GR and TiO2-GR nanoparticles have smaller crystalline size and higher surface area than pure TiO2. Presence of highly dispersed Au nanoparticles...
Studying of possible remedies for solving environment problems of coal spoil and making them economical
, Article 5th International Conference on Environmental Informatics, ISEIS 2006, 1 August 2006 through 3 August 2006 ; 2006 ; Afshoon, M. R ; Hashemian, S. J ; Alamolhoda, A. A ; Sharif University of Technology
International Society for Environmental Information Sciences
2006
Abstract
Site visits of selected factories and mines show large amounts of coal were collected as spoil and waste outside these locations due to un-efficiency of coal exploiting technology from mined material. The coal content of these waste materials is about 60%. In this work, we propose a method to be used for complete consumption of these materials in industry. In some samples, volume and weight of spoils could be decreased by half. This review also shows that aluminum oxide in industrial and minerals spoils are high, in some samples up to 25%. We suggest some remedies, e.g. we can use ashes produced by complete combustion of coal for production of aluminum hydroxide thus making it economical....
Application of Magnetic Grapheme Oxide Coated by Modified Carboxymethyl Cellulose as a Nanoadsorbent to Dye Removal
, M.Sc. Thesis Sharif University of Technology ; Pourjavadi, Ali (Supervisor) ; Alamolhoda, Ali Asghar (Supervisor)
Abstract
There are many industries in the world that produce colorized wastewater. Because of the complex structure and good solubility of dyes, such industries have problem treating this wastewaters. On the other hand, because of the toxicity of these materials for water living, dye removal from discharged wastewater of these industries is very important. In recent years, researchers have become interested in the synthesis of dye Nano adsorbents and they have published many works on this subject. The important parameters in the synthesis of such adsorbent include; non-toxicity, high adsorption capacity and easy separation. In this project, cellulose was extracted from bagasse and then CMC was...
Field Performance of a Mechanical Spray Evaporator in Wastewater Minimization & Disposal
, M.Sc. Thesis Sharif University of Technology ; Alamolhoda, Ali Asghar (Supervisor) ; Hashemian, Jamaledin (Co-Advisor)
Abstract
The mechanical spray evaporator (MSE) is a method of enhanced evaporation technology, normally designed to reduce the particle size of a wastewater droplet to volatilize water content of it as quickly as possible. A model of MSE has been built at the Institute of Water and Energy at Sharif University of technology. The aim of this research is to study the efficiency of enhanced evaporation technology for waste disposal. To achieve the accurate results, the required pumping rates and power consumption, sustained evaporation rates while operating the fans, and the performance during various temperature, wind speed and relative humidity, are required. Mechanical Spray Evaporator technique...