Sharif Digital Repository

Microfluidics is the science of fabricating systems interfacing fluids of small volume and size ranging from microliters (10-6) to picolitres (10-12). Due to its remarkable features, such as low sample and reagent consumption, high sensitivity, low cost, automated devices, and short experimental time, microfluidic chips have been widely used as laboratory assays. As a term often used and described in “lab on a chip” and “organ on a chip” technologies, microfluidic chips have been used in the fast and frugal diagnosis of infectious diseases such as HIV, microscale surgery on single cells and tiny organisms and cell culture.The design, simulation, optimization, and fabrication of an... 

Low carbon steel is widely used in the automotive industry by improving ductility and minimizing hardness to achieve greater strain. Applying severe plastic deformation to metals and alloys increases strength and decreases ductility. In the process of severe plastic deformation, the pressure is limited in the grooved form. Low carbon steel, after two passes of severe plastic deformation, experiences a rapid drop in strength in addition to ductility, which may indicate the presence of microcracks. Therefore, in this research, annealing between passes during the pressure process in the form of limited grooves has been used so that without a serious decrease in strength, some ductility... 

Microfluidic technology is a field of science that deals with the design, implementation, optimization, and testing of fluid systems in small dimensions. This technology has made significant progress in various fields in the last decade, especially in medical engineering. As an interdisciplinary scientific field, this growing technology has many applications in medicine, pharmaceuticals, chemistry, and electronic industries. One of the primary applications of microfluidic devices is the development of "lab-on-a-chip" systems as point-of-care diagnostic tools, such as rapid diagnosis during surgery. A microfluidic system includes various functional modules: sample preparation and fluid... 

In nuclear power plants (NPPs), the integrity of the Reactor Pressure Vessel (RPV) is one of the most essential issues in assessing the life of the NPPs. The RPV in a nuclear power plant cannot be replaced during plant life. Hence, maintaining the integrity of the RPV nuclear power plant is of great importance. In this study, the RPV integrity of Boshehr Nuclear Power Plant (BNPP) gainst crack formation and growth in the case of LBLOCA is evaluated and studied by the finite element method (FEM) in ABAQUS using the J-Integral method and also the weight function, which is a function of crack shape. According to the results, stress values increased significantly during the LBLOCA incident. The... 

Selection of appropriate thermohydraulic tool for analyzing nuclear reactors is a trade of between accuracy and calculation run-time. Nuclear reactors analyses perform on two levels including system and sub-channel. In this regard or the system codes' one-dimensional approach is selected or the CFD codes for considering the three-dimensional and non-equilibrium phenomenon are employed. In this research a T-H tool for prediction of light-water cooled reactors core is developed. Although this code requires lower CPU and run-time in comparison with CFD codes, in contrast with system codes can report non-equilibrium and three-dimensional phenomenon. This code has a modular implementation based... 

In this research, a Reusable Flexible Launch Vehicle (RFLV) design problem is presented by Multi-Disciplinary Design Optimization (MDO) approach in primary design phase. Trajectory, structure, aerodynamic, aeroelasticity and thermal protection system are considered as involved disciplines in design problem. The study purpose will be to obtain an optimal trajectory which meets all the control and structure limitation while the estimating body skin and thermal protection thicknesses base on structural evaluating in re-entry trajectory is in process. The flexible launch vehicle body is considered as a free-free Bernoulli-Euler beam and D’alembert’s principle addresses inertia force in static... 

Cloud computing has provided a suitable platform for processing and storing Internet of Things data over the last few decades by establishing data centers with high processing power. Today, with the rise of real-time processing applications in the Internet of Things, such as voice assistants, smart health controls, and self-driving cars, the number of real-time tasks has increased rapidly; this is despite the fact that cloud servers cannot meet the deadline constraint due to physical distance delays. To address this challenge, Fog computing has been introduced. By moving computational and storage resources closer to the edge of the network, fog computing enables executing real-time tasks... 

Clustered Regularly Interspaced Short Palindromic Repeats, or in short, CRISPR is a relatively new technology that enables geneticists and medical researchers to edit parts of the genome by removing, adding, or altering parts of the DNA. Initially found in the genomes of prokaryotic organisms such as bacteria and archaea, this technology can cure many illnesses such as blindness and cancer. A significant issue for a practical application of CRISPR systems is accurately predicting the single guide RNA (sgRNA) on-target efficacy and off-target sensitivity. While some methods classify these designs, most algorithms are on separate data with different genes and cells. The lack of... 

Shear modulus and damping ratio are the most important parameters for evaluating and designing the performance of geotechnical systems under dynamic loads. According to the definition, the secant shear modulus is the slope of the hysteresis shear stress-shear strain loop. Also, the damping ratio indicates the dissipation of wave energy during propagation in the soil. This research presents an experimental laboratory study on the effect of non-plastic fines content and hydraulic hysteresis on the Gmax of unsaturated sand-silt mixtures. A significant part of the previous research has been done to determine Shear modulus and damping ratio parameters. It has been done in completely saturated or... 

We examined the Phase-Type distribution to calculate project activity duration and solve the resource constraint project scheduling problem with non-deterministic activity duration through meta-heuristic techniques. The activity usually doesn't have a fixed duration. The problem is caused by numerous factors that exist when carrying out a project, such as a lack of resources, late delivery of resources, and mistakes made by people. The literature review revealed that the scheduling problem had been thoroughly researched. The more accurate and realistic the activity duration estimates, the better the project planning and cost control. For this purpose, in this research, the duration of the... 

There are several case history records of liquefaction in gravelly layers with more broadly-graded particles than uniform sands which have been typically examined. Liquified deposits, in many cases, were subjected to initial static shear stress associated with the sloping ground condition or the adjacent shallow foundations prior to liquefaction. There are several graphs and recommendations for practitioners to consider the effects of the initial static shear stress on liquefaction resistance in design processes, developed based on the results of experiments on uniform clean sands. However, data for the effect of the initial static shear stress on the liquefaction strength of gravelly soils... 

Bridges play a vital role in road-related transport industries. Significant changes to contemporary bridge design specifications have also been mainly related to strength issues. The transitions from allowable stress design to load factor design, and more recently to load and resistance factor design (LRFD), reflect this line of thinking. It is important to note that in the early 1970s, bridge engineers developed criteria for steel bridge details to protect against fatigue and fracture failure. These were indeed service life design provisions. By industry growth and extensive need for goods transportation, there is a need for the construction of new bridges and renewal of older bridges plus... 

Additive manufacturing enables fabricating lattice structures with tailored mechanical responses based on lattice materials. Full exploitation of such a possibility requires reliable and efficient mechanical analysis tools to be explored by topology optimization algorithms for designing the interior architecture of the structures to meet the desired mechanical behavior. However, detailed mechanical analysis of lattice-based structures using the conventional finite element approach is prohibitively expensive due to lattices’ complex and fine features that demand adopting very fine space discretization. As an alternative, equivalent models based on the homogenization principle have widely been... 

Nowadays, in the world and our country, Iran, sediment transport and the phenomenon of sedimentation are of great importance. The entry of water flow with suspended sediments into the dam reservoir by floods with different return periods during the initial period of dam construction causes a considerable part of the helpful volume of the reservoir to be filled with sediments. As a result, the discharge of these sediments and the methods that exist in this field should be studied so that a large volume of reservoir water is not wasted during the discharge of these sediments. In this research, the opening time and extent of the bottom outlets of Qeshlaq Dam when the flood enters the reservoir... 

Dams are constructed for various purposes, including flood control, drinking water supply, agriculture irrigation, electricity generation, etc. The dam converts the river's natural and dynamic flow into a stagnant artificial lake where humans control the outflow of water, reducing the velocity of water movement and increasing residence time, followed by the entry and accumulation of nutrients in the reservoir, resulting in phenomena such as thermal stratification and eutrophication. Due to the changing climatic conditions of Iran and sudden droughts and wet periods, the need to monitor the water level of dam reservoirs and their water quality to keep them in the best operational condition... 

Cyber-Physical Systems, including embedded systems, have become essential components of various applications in modern life. Due to this fact, cyber-physical and embedded systems must be reliable, safe, and meet timing constraints. Task replication is an effective approach to improve reliability and safety, but it may violate the real-time constraints of the executing tasks and aggravate the aging effects of the system due to elevating the on-chip temperature. Moreover, since embedded systems have time, reliability, power, and thermal constraints, the appropriate number of replicas should be determined to handle the extra overheads. Existing works determine the number of replicas at design... 

In fractured reservoirs under the gravity mechanism, the oil transfer between the matrix blocks is affected by mechanisms such as capillary continuity or re-imbibition. Capillary continuity between adjacent matrix blocks can be created by formation of liquid bridges, or physical contact of surfaces due to the roughness of the fracture wall surface.Since the presence of liquid bridges can be effective in creating capillary continuity and therefore the amount of oil production, the study of the presence of liquid bridges between matrix blocks and how they change in terms of volume and shape in the process of oil and gas movement is of particular importance. Although there are studies on the... 

In this thesis, the accelerator and cooling equations have been investigated in order to improve the quality of the accelerator by using cooling. With the help of MATLAB software, a cooling method has been proposed that can have a relatively uniform temperature throughout the accelerator. In order to optimize and minimize the number of coolers for each desired temperature difference and each number of coolers, an arrangement of coolers is found so that the temperature difference is minimal. There are different types of charged particle accelerator systems in terms of the structure and energy of the output particles. Linear accelerators are accelerators in which charged particles move along a... 

Corneal keratoconus is one of the common eye diseases that usually occurs in the teenage years or the beginning of the third decade of life. In this disease, the cornea thins and loses its original shape and becomes conical. To treat this disease, ophthalmologists use different methods such as using glasses, contact lenses (hard and soft), corneal transplantation, and also corneal cross-linking, each of these methods has limitations, on the other hand, considering that The disease progresses and its severity increases, Ophthalmologists use corneal rings to treat this disease in more advanced stages, implanting a suitable ring in the patient's cornea both increases the strength of the... 

The Emergency Department is one of the most important departments in a hospital, which is continuously active and plays a crucial role in saving patients' lives. For this reason, using research methods in operations and optimization can greatly help improve the performance of the Emergency Department. In this thesis, the emergency scheduling problem is examined with the objective function of minimizing the total weighted sum of job completion times, considering the random nature of service times. Since the objective function of the problem is to minimize the total job completion time, the job completion time is obtained as the sum of several random variables. Considering the additivity...