Sharif Digital Repository

The most applications of gold nanoparticles are in the photo-electronical accessories and bio-chemical sensors. Chloride solution with cysteine additive was used as electrolyte in gold nanoparticles electrodeposition. The nucleation and growing mechanism were studied by electrochemical techniques such as cyclic voltammetry and chronoamperometry, in order to obtain a suitable nano structure. The deposition mechanism was determined as instantaneous nucleation and the dimension of particles was controlled in nanometric particle size range. Atomic Force Microscope was used to evaluate the effect of cysteine on the morphology and topography of gold nanoparticles. Finally the catalytic property of... 

Carbon emissions significantly contribute to global warming, amplifying the occurrence of extreme weather events and negatively impacting the overall environmental transformation. In line with the global commitment to combat climate change through the Paris Agreement (COP21), the European Union (EU) has formulated strategies aimed at achieving climate neutrality by 2050. To achieve this goal, EU member states focus on developing long-term national strategies (NLTSs) and implementing local plans to reduce greenhouse gas (GHG) emissions in alignment with EU objectives. This study focuses on the case of Sweden and aims to introduce a comprehensive data-driven framework that predicts CO2... 

A respiratory system combines a blower-hose-patient setup with a single lung system featuring nonlinear lung compliance. This paper explores the optimal design of resilient fuzzy control for such systems by integrating a fuzzy algorithm with a sliding mode control approach. The robust fuzzy controller, as proposed, effectively handles the system's dynamics and remains stable amidst nonlinear changes. It ensures airway flow and maintains peak pressure below critical levels despite uncertainties like hose leakage and varying respiratory effort. The findings show superior performance in reaction time, overshoot, and tracking errors compared to traditional methods. The control mechanism's... 

Energy demand in Iran is increasing because of many reasons, for instance, low price, population and GDP growth. Its trend shows that this situation could not continue for many years, so it needs reviewing in energy policy in Iran. The aim of this paper is reviewing the whole energy system of Iran and its possible future and offering some policies for solving current and future problems. First of all, this study investigates the trend of growth of some parameters like GDP, electricity price, population, CO2 emission and electricity consumption in eight years. After that, by calculating the price of electricity generated in Iran under three different circumstances, this study is able to... 

Stress is a body's natural way of responding to any kind of demand or challenge that everyone experiences from time to time. Although short-Term stress typically does not impose a health burden, exposure to prolonged stress can lead to significant adverse physiological and behavioral changes. Coping with the impact of stress is a challenging task and in this context, stress assessment is essential in preventing detrimental long-Term effects. The public embracement of connected wearable Internet of Things (IoT) devices, as well as the proliferation of Artificial Intelligence (AI) and Machine Learning (ML) technologies, have generated new opportunities for personalized stress tracking and... 

A new structure for the compression surfaces of a supersonic inlet is proposed which has improved the target performance parameter i.e. total pressure recovery ratio. This idea resulted in development of a new type of supersonic inlet, utilized four ramps and a cone simultaneously as the compression surfaces. A prototype of the proposed inlet has been designed for a free stream Mach number of 3 and its performance has been evaluated via numerical simulation for both design and off-design conditions. The performance of the newly designed inlet has been compared to the existing experimental data of two double-cone inlets. The acquired data are further compared with analytical calculations of... 

This article reports on a method for detecting disconnection between electric vehicle parking lots during charge management and uncertainties and how to deal with these issues. In this study, each parking lots has an aggregator that can exchange information with other parking lot aggregators through a communication graph. A cyber-attack or communication failure may cause a problem in the connection between the aggregators and their information exchange. To detect the loss of contact between the aggregators or uncertainties, a method based on the mean field game is developed through a distributed consensus algorithm. Since the number of vehicles in every parking lot, power consumption and... 

In this work, energy management of home customers with electric vehicles and renewable resources is modelled in the form of multi-agent systems. The agent decisions affect the others and the mean field game theory could provide a good solution for decision-making and control in multi-agent systems with a large number of agents. Due to uncertainties in the number of cars, power consumption, and production, online optimisation process is proposed by using the receding horizon concept of predictive control. The main problem in such processes is the calculations each agent should perform every hour. Hence, an event-based optimisation is employed to reduce the computational load. The main... 

In this paper, an underwater wireless sensor network (UWSN) is modeled with the help of queueing theory in order to evaluate the maximum stable throughput of the network. To this end, a new scenario for multi-layer mobile UWSN is considered. Then, a new MAC algorithm comprised of random access scheme (like MACAW) and CDMA-based data transmission along with a simplified routing algorithm is proposed. In order to analyze the considered UWSN scenario, we propose two related queueing networks, one for modeling the wireless node mobility and the other for representing the process of multi-hop packet transmission according to considered MAC and routing algorithms. Finally, the maximum stable... 

A simplified efficient finite element method called the inverse approach (IA) has been developed to estimate initial blank and strain distribution in sheet metal forming. This algorithm is an inverse method since the position of points in final shape is known and their corresponding position in the initial blank should be determined. This approach deals with the geometric compatibility of finite elements, plastic deformation theory, and virtual work principle. This method often based on implicit static algorithms, sometimes causes convergence problems because of strong nonlinearities. This paper introduces an initial guess to speed up the convergence of Newton- Raphson solution. The... 

Frequent dust storms originated from Middle Eastern deserts impact major cities in Iran, including Tehran. Previous studies identified Iraqi and Syrian deserts as the main cross-border contributors to Tehran Particulate Matter (PM) levels. In this study, the contribution of Iraqi and Syrian dust storms to Tehran's PM10 and PM2.5 concentration were assessed during a dust storm episode. Initially, a dust storm event was identified through the statistical analysis of the recorded air pollution data at Tehran's monitoring stations and the visual inspection of the satellite images. A combination of CMAQ/WRF/SMOKE modeling systems was used to simulate PM concentrations from Tehran local sources... 

The production with high quality at the lowest production time can be a key means to success in the competitive environment of manufacturing companies. Therefore, in recent years, the need for extra precise and high-speed machine tools has been impressively increased in manufacturing applications. One of the main sources of errors in the motion of high-speed spindles is the occurrence of non-repetitive runouts (NRRO) in the bearing. The NRRO can be caused by some factors such as the form of balls, the waviness of rings, the number of balls, and the permutation of one or two balls in the ball bearing. In this paper, a Taguchi-based approach is proposed for the optimal design of high-speed... 

Polypropylene (PP) is a semi-crystalline polymer with a very wide range of industrial applications. This is why its mechanical properties, including yielding, have been the subject of numerous studies. The current study has examined the influence of strain rate and thermal softening on yield stress and post yielding behavior of an isotactic PP. A two-process Ree and Eyring model and the heat equation in adiabatic deformation were coupled with a physical parameter described as the temperature sensitivity of the flow stress at yielding, to simulate the effect of gradual temperature rise in adiabatic heating on yielding behavior. Along with that, tensile bars were subjected to tests at... 

Polypropylene (PP) and its composites have an increasing use in automobile and domestic industries. Since the results published regarding effect of strain rate on yield behavior are not compatible, and there is a high attention paid to the effect of strain rate on deformation behavior, the understanding of structure–property relation in PP is crucial. In this research, the effect of strain rate on deformation mechanism of PP and its relation with stress whitening have been studied. Microscopic observations and tensile tests in different strain rates on neat PP samples have suggested that crazing is the prominent deformation mechanism in entire range of the examined strain rates... 

The evolution of the organizational attitudes regarding strategic management of system physical assets and the emergence of new technologies call for special attention to maintenance and reliability. State-of-the-art literature suggested a number of techniques and strategies for estimating the equipment failure rates; however, paralyzed by lack of real-world data, existing literature mostly relied on simplifications that may bring about unique challenges and result in low-accuracy estimations. This paper reviews the existing literature in estimating and modeling the failure rate of power system equipment. The review includes the existing models and the ongoing research on degradation,... 

Predictive business process monitoring is concerned with predicting the process-related Key Performance Indicators (KPIs) and forecasting the future behavior of the process in realtime. Despite the amount of work contributed by researches to this field of research, the performance of existing solutions is not desirable for practical settings. Indeed, these approaches are typically context-unaware and lack generality. However, in real-life use cases, business processes are not isolated from the surrounding working environment, and thus they are influenced by many contextual events, such as events generated by IoT devices. To the best of our knowledge, there is no comprehensive study... 

The oxidation of sponge iron products and its destructive effects on iron content as well as other properties have been considered by ferrous technologists for a long time. In this investigation, a unique new low temperature method of preventing and/or retarding the oxidation of direct reduced iron is introduced. Experimental results from laboratory and pilot plant tests show the success of the method which has been named cold briquetting of sponge iron. The optimum condition for briquetting is achieved at 80 kN (Lcm)-1, 6% binder, 10% sponge iron fines and 4% anthracite. While hot briquetted iron has become a successful method for the new generation of iron reduction plants, cold... 

A numerical code for supersonic intake design with a proper simulation of the normal and/or oblique shocks, boundary layer development, interaction of the shock and the boundary layer, as well as prediction of the flow separation is of great help to the designers. In this research, a numerical code is developed to solve the inner and outer flow fields of the intake and validated with various experimental tests. The intake is an axisymmetric external compression one. Roe scheme and new schemes, AUSM+-up (for all speed) and Advection Upstream Splitting Method with Pressure-Based Weight function (AUSMPW), are used to compute the convective fluxes. The original version of the AUSMPW scheme has... 

The performance and the buzz onset of a supersonic mixed-compression axisymmetric intake are experimentally investigated. Effectsof the slot bleed position, angle, and width onthe intake performance and onthe buzz initiation at three different Mach numbers of 1.8, 2.0, and 2.2 and at a zero degree angle of attack are studied. The intake performance is assessed using the total pressure recovery, mass flow ratio, flow distortion, and bleed mass flow ratio. The results show that applying the bleed at a position near the intake entrance and reducing the bleed entrance slant angle and width all improve the intake performance considerably. Moreover, these parameters postpone the buzz onset. In... 

Hardware/Software (HW/SW) partitioning plays one of the most important roles in Co-design of embedded systems that is due to made at the beginning of the cycle of the design. The ultimate designed system's performance strongly depends on partitioning. Therefore, achieving the optimum solutions can reduced the systems cost and delay. On the other hand, Genetic algorithms (GAs) are powerful function optimizers that are used successfully to solve problems in many different disciplines. Parallel GAs (PGAs) are particularly easy to implement and promise substantial gains in performance and results. In this paper, we present a PGA-based approach to achieve near optimal solutions for HW/SW...