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Resolution Improvement of a Resin 3D Printer via an Optical System and Adjusting the Affective Parameters of Light on the Curing Accuracy for Micro-scale 3D Fabrication
, M.Sc. Thesis Sharif University of Technology ; Mohammadi, Kaivan (Supervisor)
Abstract
Nowadays, with the increasing need to design and manufacture parts with dimensions less than 1 millimeter in various fields such as medicine, drug delivery, microfluidics, precision casting, and many other areas, methods for manufacturing such parts have gained significant attention. Numerous studies have been conducted to develop 3D printing methods for manufacturing increasingly smaller parts, with optical 3D printing research being at the forefront. In this regard, researchers have enabled the achievement of smaller parts by developing in three areas: increasing the resolution of the light source, changing the resin compositions, and improving the accuracy and correction of image pixels....
An Efficient Algorithm to Solve the Joint Road Reopening and Emergency Relief Problem after a Severe Earthquake in Urban Areas
, M.Sc. Thesis Sharif University of Technology ; Poorzahedi, Hossein (Supervisor)
Abstract
The purpose of this study is to solve the problem of allocating relief teams to reopen damaged roads and remove debris from damaged areas after the earthquake for large cities. In the deteriorated areas of large metropolises, severe earthquakes may damage links, which causes some nodes to separate from the network. In this research, by using an Ant System meta-heuristic algorithm, a joint problem of damaged link restoration and demolished zone debries removal problem for search and rescue of the trapped population in an earthquake is solved. Ant System parameters are calibrated, and sensitivity analyses are done for the number of relief teams, earthquake intensity. The results of 1000...
Fuzzy adaptive sliding mode control for a class of uncertain nonlinear MIMO systems with application to a 2DOF twin propeller
, Article 10th International Fuzzy Systems Association World Congress, IFSA 2003, 30 June 2003 through 2 July 2003 ; Volume 2715 , 2003 , Pages 500-507 ; 03029743 (ISSN); 3540403833 (ISBN); 9783540403838 (ISBN) ; Bolandhemat, H ; Dadkhah Tehrani, N ; Sharif University of Technology
Springer Verlag
2003
Abstract
A practical design method is presented which used the fuzzy logic advantages in adaptation of sliding mode control. The combined Fuzzy Adaptive Sliding Control (FASC) is designed in such a way to enhance satisfactory sliding performance and robustness with good level of chattering alleviation. The design approach is valid for a class of nonlinear uncertain MIMO systems. This control algorithm does not require the system model. A supervisory term is appended to the controller to assure the stability of fuzzy sliding mode control through Lyapunov theory. The design approach has been applied to a 2DOF twin propeler system with large uncertainty. Simulation results verified effectiveness of...
Preparation of Acrylamide Copolymers Containing Highly Hydrophobic Monomers and Study on Their Drag Reduction Properties
, M.Sc. Thesis Sharif University of Technology ; Ramazani Saadatabadi, Ahmad (Supervisor)
Abstract
With the rapid increase of energy consumption, energy problem has been a global issue, which must be faced with and solved. One way to prevent energy consumption is to reduce drag in the flow inside the pipes by using polymer additives; Because the Transportation of liquids using pipeline technology has its limitations, since turbulent flow inside the pipe involves a loss of energy. The net effect of this is that increasing the energy applied to the flow does not increase the flow rate. For this purpose, copolymers and terpolymers of hydrophilic acrylamide monomers along with hydrophobic styrene and hydrophilic maleic anhydride monomers were synthesized by reverse emulsion polymerization...
Numerical Modeling of Turbine Flow Meter and Improving its Performance Using CFD
, M.Sc. Thesis Sharif University of Technology ; Karimi, Mohammad Sadegh (Supervisor)
Abstract
Studying the performance of flow meters is of great importance in order to improve their quality. In this study, we are looking for an optimal design for a turbine flow meter in which the measurement accuracy, pressure drop and response speed indices are improved. For this purpose, a turbine flow meter with a diameter of 2 inches has been selected and its performance has been numerically modeled using computational fluid dynamics in a steady and transient state. By modeling the steady state, the measurement accuracy and pressure drop indices are obtained, and by modeling the transient state, the response time of the flow meter is obtained. In order to increase the accuracy of numerical...
Isolation of Motile Sperm Using a Microfluidic Device
, M.Sc. Thesis Sharif University of Technology ; Taghipoor, Mojtaba (Supervisor) ; Montazeri, Leila (Supervisor)
Abstract
In this work a new innovative microfluidic system for the selection of motile sperms was developed. The novel aspect of this work is based on the fact the motile sperms follow microchannel walls. Immotile sperms are not able to follow curved paths and therefore their movement toward the outlet gets hindered and most of them could not reach to the outlet. But motile sperms, moving alongside the microchannel walls, reach to the outlet and get separated from the immotile ones. After designing, 3 microfluidic chips having curved microchannels with curvature radius of 150, 300 and 600 micrometer and one with a straight microchannel were fabricated using photolithography and soft lithography....
Development of a novel cervix-inspired tortuous microfluidic system for efficient, high-quality sperm selection
, Article Lab on a Chip ; Volume 23, Issue 13 , 2023 , Pages 3080-3091 ; 14730197 (ISSN) ; Hajari, M. A ; Abdorahimzadeh, S ; Shahverdi, A ; Esfandiari, F ; Ziarati, N ; Taghipoor, M ; Montazeri, L ; Sharif University of Technology
Royal Society of Chemistry
2023
Abstract
Microfluidic systems have been extensively studied in recent years as potential alternatives for problematic conventional methods of sperm selection. However, despite the widespread use of simple straight channels in these systems, the impact of channel geometry on selected sperm quality has not been thoroughly investigated. To explore this further, we designed and fabricated serpentine microchannels with different radii of curvature, inspired by the tortuous structure of the cervix. Our results showed that in the presence of gentle backflow, microfluidic channels with a 150 μm radius of curvature significantly enhanced the quality of selected sperms when compared to straight channels....
A self-healable and bioadhesive acacia gum polysaccharide-based injectable hydrogel for wound healing acceleration
, Article DARU, Journal of Pharmaceutical Sciences ; Volume 31, Issue 2 , 2023 , Pages 205-219 ; 15608115 (ISSN) ; Jelodar, M. Z ; Rashidipour, M ; Dadkhah, M ; Adhami, V ; Sefareshi, S ; Ebrahimi, H. A ; Ghasemian, M ; Adeli, M ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2023
Abstract
The present study aimed at developing an injectable hydrogel based on acacia gum (AG) for wound healing acceleration. The hydrogels were synthetized through metal-ligand coordination mediated by Fe3+ and characterized in terms of gelation time, gel content, initial water content, swelling capacity, water retention ratio, and porosity. Moreover, FTIR, XRD and TGA analyses were performed for the hydrogels and allantoin (Alla) loaded ones. Furthermore, bioadhessiveness, and self-healing as well as antibacterial, toxicity and wound healing potentials of the hydrogels were evaluated. The hydrogels displayed fast gelation time, high swelling, porosity, and bioadhessiveness, as well as antioxidant,...
Microfluidics: the future of sperm selection in assisted reproduction
, Article Andrology ; 2023 ; 20472919 (ISSN) ; Ziarati, N ; Dadkhah, E ; Numan Bucak, M ; Rahimizadeh, P ; Shahverdi, A ; Sadighi gilani, M. A ; Rezaei Topraggaleh, T ; Sharif University of Technology
John Wiley and Sons Inc
2023
Abstract
Background: Obtaining functional sperm cells is the first step to treat infertility. With the ever-increasing trend in male infertility, clinicians require access to effective solutions that are able to single out the most viable spermatozoa, which would max out the chance for a successful pregnancy. The new generation techniques for sperm selection involve microfluidics, which offers laminar flow and low Reynolds number within the platforms can provide unprecedented opportunities for sperm selection. Previous studies showed that microfluidic platforms can provide a novel approach to this challenge and since then researchers across the globe have attacked this problem from multiple angles....