Sharif Digital Repository

The fascinating size-dependent properties of noble metal nanop articles have created a great promise for their use in a different applications specially chemical sensing. Gold nanorods (GNRs), specifically, have received a great deal of attention due to their unusual optical properties. The nanoscale confinement of electrons on the surface of gold nanorods grants them aspect ratio-dependent properties not seen in larger particles. Due to the intriguing properties of GNRs, significant work has gone into the application of nanorods for sensing and detection of various an alytes in biological and other systems. The major modalities which have been developed for... 

There is a growing interest in developing high-performance sensors monitoring organophosphate pesticides, primarily due to their broad usage and harmful effects on mammals. In the first part of this research, by introducing conditional sensor elements (CSE), a colorimetric sensor array has been proposed for the detection and discrimination of several organophosphate pesticides (OPs). citrate-capped 13 nm gold nanoparticles (AuNPs) at nine different pH/ionic strengths were employed as simple plasmonic sensing elements in the development of a colorimetric sensor array for the detection and discrimination of five organophosphate pesticides, including azinphos-methyl (AM), chlorpyrifos (CP),... 

In the nuclear industry, gas centrifuges are considered of high importance for the purpose of uranium enrichment. Today, with advances in science and technology, the use of gas centrifuges for separating isotopes other than uranium, is so common. With respect to the use of conventional methods such as Pancake equation in calculating the velocity profile in centrifuges, it is needed that A^2=(MV^2)/2RT≫1 (M: Feed molecular weight; V: Peripheral speed of centrifuge; T: Mean temperature of feed; R: The universal constant of gases). While the molecular weight of the feed mixture gets lower, the A2 parameter gets closer to one. So, other methods for modeling the behavior of the gas in the... 

The Vehicle Routing Problem with Simultaneous Pick-up and Delivery (VRPSPD) and maximum time for traversing of each tour is a variant of the classical vehicle routing problem (VRP) where clients require simultaneous delivery and pick-up. Deliveries are supplied from a single depot at the beginning of the vehicle’s service, while pick-up loads are taken to the same depot at the conclusion of the service. Also the required time for traversing each route should not encroach the specified limit.
In this research, the aforesaid problem was introduced and a mixed integer programming model developed for it. Because of being NP-Hard and impossibility of solving it in the large instances, two... 

In this thesis, an attempt has been made to fully investigate a hybrid power plant in terms of production capacity and construction and maintenance costs, and finally a proposed model of a hybrid converter for one of the country's port cities with cost and production capacity estimates based on The existing conditions in that area should be presented so that one can have a comprehensive vision of an offshore power plant in that area and the ability to estimate the final cost before construction is available  

Reduced mechanisms are widely used in the numerical simulation of turbulent combustion, motivated by the need to reduce computational costs. Tabulation is widely used in turbulent and reacting flow simulations. Still, the need for a huge memory, the high cost of searching and interpolating among the data, and the development of artificial neural networks have created a situation for combining these two sciences. In this research, to model the chemistry of a methane premixed flame, we produced several training databases using the flamelet generated manifold, the best of which is the database with five degrees of freedom. We used these data to train individual neural networks for the... 

This study investigates the factors influencing the acceptance of digital health technologies in Iran by employing a modified version of the Unified Theory of Acceptance and Use of Technology (UTAUT2). The significance of understanding user acceptance is underscored within the context of digital health ecosystems, which consist of various stakeholders, including healthcare providers, technology companies, and patients. These platforms serve as vital interfaces that connect these stakeholders, facilitating access to healthcare services and enhancing health outcomes. The literature review reveals that while traditional models like TAM and UTAUT2 have been widely applied, they often overlook... 

The Architecture, Engineering, and Construction (AEC) industry worldwide has increasingly turned its attention to the application of Building Information Modeling (BIM) due to its numerous advantages. Educational institutions have been urged to integrate this technology into their curricula so that new graduates can acquire the necessary competencies and expertise to keep pace with industry developments and take full advantage of BIM. Building Information Modeling involves automated processes that significantly reduce discrepancies between planned and constructed models, save time and cost, prevent errors, and mitigate risks. The process of introducing this technology into universities has... 

The purpose of this study is to provide a framework to demonstrate the organizational capabilities of chemical knowledge-based firms and analyze the relationship between these capabilities and exports. For this purpose, by combining 18 different output-based indicators, a model that includes six technological, manufacturing, research and development, marketing, organization and finance capabilities, was designed. Finally, in addition to analyzing the relationship between exports and the level of capabilities of knowledge-based firms, a comparison between the two groups of export and non-export firms and the analysis of these firms' current export situation was made in the period 2015-2018.... 

The purpose of this study is to present a suitable model for calculating the costs imposed on society due to deaths and injuries due to infrastructure failure due to earthquakes, which is used in the analysis of community resilience. Much research has been done to date to calculate the economic costs of infrastructure failure. However, no suitable analytical framework has been provided to quantify the costs of deaths and injuries to people due to earthquake failure. Previous research has provided methods such as the value of statistical life to quantify the social costs caused by accidents and environmental pollution. However, the literature review results in the field of seismic resilience... 

This study investigates the possibility of knowledge transfer from military industries, with a focus on the missile industry, to other sectors in the country, particularly the automotive industry, from the perspective of technological capabilities. The objective of this research is to conduct a comparative analysis of the technological capabilities of these two industries and to evaluate the potential and challenges associated with the process of knowledge and technology transfer. The research methodology involves qualitative analysis through interviews with experts and the review of relevant documents and records. The conceptual framework has been developed based on existing models of... 

Fault occurrence is an inevitable problem in industrial plants. These faults have numerous types. Some common kinds of faults are faults in actuators, faults in system dynamics, and faults in sensors. In many cases it is not possible to change or repair the broken part immediately. On the other hand, it is not reasonable to shut-down the whole system due to a minor failure. Therefore we should take a measure to have the best output possible in a faulty plant. In this thesis we have proposed a new static compensator by which we distribute the contribution of the faulty actuator among the other ones. At the end we evaluate the method by means of simulations  

Electrodeposition is an old, well known and conventional science surface modification method to improve the surface characteristics, decorative and functional, of a wide variety of materials. This science is considered in nanotechnology as a bottom-up method for fabrication of one, two and three-dimensional nanomaterials. A great variety of secondary components can be added to plating baths resulting in metallic matrix composite and nanocomposite coatings production. Low amounts of iron addition for alloying zinc coatings, significantly increases the corrosion resistance of this generally used metal economically. Superhydrophobic coatings on metallic substrates have shown, during the past... 

Given a set of obstacles as an arrangement of geometric shapes in the plane, we would like to find a path from the initial point s to the target point t that crosses the minimum number of obstacles. In other words, the goal is to determine the minimum number of obstacles that need to be removed to exist a collision-free path between s and t.On one hand, this problem can be used for measuring the strength of barrier coverage which is a fundamental concept in wireless sensor networks (WSNs), and on the other hand, it has been considered as a robot motion-planning problem. The objective of barrier coverage is to guarantee that any path from the start point to the target point, will intersect at... 

High-quality online services demand reliable and fast packet delivery at the network layer. However, clear evidence documents the existence of compromised routers in the ISP and enterprise networks, threatening network availability and reliability. A compromised router can stealthily drop, modify, inject, or delay packets in the forwarding path to launch Denial-of-Service, surveillance, man-in-the-middle attacks, etc. So researches tried to create intrusion detection methods to identify adversarial routers and switches. To this end, data-plane fault localization (FL) aims to identify faulty links and is an effective means of achieving high network availability. FL protocols use... 

Confining nematic liquid crystal between two curved boundary conditions while the nematic molecules have a degenerate planar anchoring leads to complex and beautiful textures of molecular disparagement(defect) in the bulk and on the surfaces. Such the liquid crystal shells are made with double-emulsion techniques in microfluidic devices have provided applications for micro-scale colloidal linkers.In this work, we have numerically minimized the elastic energy in one-constant approximation in present of Fournier’s degenerate surface potential with finite element method. The nematic shell is confined between two spherical surfaces that we have studied the final energies and their related... 

A liquid crystal is a state of matter composed of highly anisotropic building blocks. When liquid crystals are exposed to surfaces with given shapes and anchoring conditions, the orientation of their molecules gets spatially disordered and topological defects may form in the system. The interplay between liquid crystals and the geometry and topology of the colloidal particles has motivated extensive recent studies.In this thesis, we present the numerical modeling results for two faceted colloidal particles in a thermotropic nematic liquid crystal. To obtain the equilibrium nematic field with a finiteelement method, we numerically minimize the free energy of the system that based on the...