Sharif Digital Repository

The ever-increasing applications of fluids in residential areas as well as in main industries require investment to advance and optimize fluid control and their real-time flow rate monitoring. Numerous methods have been developed for measuring fluid flow rates, particularly for water. This study focuses on the design and evaluation of a sound-based water flow measurement system. As the first test, a microphone was placed on the water pipe, and through time-domain analysis, a second-degree relationship was found between the pressure amplitude of the signal and the flow rate to increase the accuracy of signal processing. Analysis of the signal-to-noise ratio revealed that the vibration of the... 

In this study, three active, passive, and hybrid thermal management systems are applied to a lithium battery module with industrial specifications, i.e., Tesla battery module, and the optimal conditions are extracted. The thermal and electrochemical behavior of battery cells is modeled using the quasi-two-dimensional approach by Newman’s method. The effects of inter-cellular distance on the maximum temperature and on the temperature distribution in the pack as the target variables are thoroughly investigated. A suitable range for the above distances is then determined in order to reduce the overall cooling power and the expected thermal performance of the pack. The results of temperature... 

Low capacity of the batteries is one of the main limitations of using them in different industries and transportation applications. For example, in fully-electrical cars, battery capacity determines the distance that could be proceeded without recharging. Although, it’s possible to increase capacity by increasing battery volume; but in cases that volume or mass is a limitation itself, this is not a practical solution. In fact, what should be considered as the real limitation is the density of capacity of batteries. The improvement in battery capacity means storing more Lithium-Ion in the anode of battery. Silicon has always been noticed as a high capacity material for using in anode. In... 

Articular cartilage is devoid of blood vessels, lymphatics, and nerves which gives it a very limited intrinsic healing and repair capabilities. Being under constant harsh biomechanical environment, makes maintaining the health of articular cartilage a vital principle in having healthy joints. Tissue engineering as a method for regeneration of damaged tissue have attracted a lot of attention. Articular cartilage engineered scaffolds act as a macro scale drug delivery system which in addition to having a good mechanical properties similar to that of cartilage tissue, have to provide a highly porous environment for cell migration and proliferation. The aim of this study is to fabricate a drug... 

As a connective tissue devoid of blood vessels, lymphatics, and nerves, articular cartilage has limited self-repair capabilities. This is because essential nutrients and signals necessary for cell proliferation are restricted. Despite advances in therapeutic approaches, complete repair of damaged cartilage remains a major challenge in medicine. Tissue engineering has attracted considerable attention as a novel approach for the repair of damaged tissues, including cartilage. In this study, a temperature-sensitive and injectable hydrogel based on chitosan-bacterial nanocellulose and silk fibroin was designed and optimized for controlled release of quercetin. After selecting a constant ratio of... 

Lithium-ion batteries have the ability to store a significant amount of energy and work at high power, which has led to the wide spread of their use in various industries. In high-power applications, battery heat management increases lifespan, safety, and reduces battery power loss. In this study, the heat management of a very common and widely used 18650 battery using multi-layered phase change material has been investigated. The reason for using multiple layers is that each phase change material has its own weaknesses in addition to its advantages. It is expected that with the proper use of several phase change materials in the thermal management system, the materials will reduce the... 

In smart grids, energy data such as electricity and gas consumption are recorded via smart sensors installed in buildings. Analyzing energy consumption patterns and classifying users based on their consumption behavior can assist policymakers in supply management and urban-scale energy control. This study proposes an unsupervised approach to classify energy consumers according to their monthly consumption patterns. The primary objective of the clustering is to group households with similar usage behaviors, facilitating a more effective analysis of electricity consumption at an urban scale. The K-means clustering algorithm is employed to classify households into K clusters based on their... 

Increasing energy consumption and limited energy resources are instances of the concerns of human societies and environmentalists today. The condensation process, as one of the most important processes in the industry, plays an important role in saving and regeneration the existing energy. Nowdays, surface optimization is one of the modern ways to improve condensation.In this research, two methods have been used to construct surfaces useful for enhancement of droplet condensation, including hybrid surfaces and solid infused surfaces. In the construction of hybrid surfaces, superhydrophobic coating with silica nanoparticles based on hydroxyl acrylic resin was used. The superhydrophilic parts... 

The notable share of housing sector in GDP (approximately five percent) shows this sector’s relation with macroeconomic activities. On the other hand, House as an asset leads housing sector to be affected by monetary and fiscal variables. A dynamic panel data was used in this study to evaluate the relations between housing sector and some macroeconomic variables in metropolises of Iran. As results show, in long term growth of liquidity, GDP per capita and sharp ratio have positive effects, and land per capita has negative effect on housing price in metropolises of Iran. Price increases have not been equal in different cities. Inequality of land price between metropolises and between... 

In this research, an Index of Iran informal economy in response to the government interventions in credit, labor and product markets is stimated by EMIMIC model. To do this, first these interventions are measured using principal components analysis. In the model, the variables GDP and employment are used as indicators and taxation rates, government distortions in credit, labor and product markets, government expenditure, per capita income, unemployment and inflation as causes of the informal economy. We conclude these government interventions have affected Iran informal economy and their influence is more than indirect interventions influence such as taxation. The estimated index of Iran... 

With altering natural state and increasing impervious surfaces, traditional urbanization leads to deteriorating the environment and water catchments. During the years most efforts in order to control the urban runoff outflow, have been focused on quantity; and awareness about improving water quality has been raised just in the last few years and, which emphasizes on pollution source control. Standard water quality sampling methods are time consuming, expensive and because of sampling in broad geographic areas, difficult; however modeling is a more efficient way in assessing water quality and as worries about non-point source pollution grows, different kinds of models have been used to... 

The role of government in economy has been a controversial subject in economics. Lately, there has been some fundamental change in evaluating this subject. One could mention two of these as 1) realizing the importance of micro-founded macro model for evaluating policy, and 2) taking into consideration the rent-seeking behavior of politicians. In this research, a general equilibrium in a micro-founded macro model will be discussed and then in political economics framework, the effect of government on this equilibrium will be investigated. Only the redistribution role of government has been considered. First, the model in which a benevolent government is seeking optimal policy is Discussed.... 

Gini coefficient is the most prevalent index for the measurement of inequality and is usually extracted by means of nominal variables based on income or expenditures of households. In this study we have extracted more accurate Gini coefficients. By using the raw data of Households Budget Survey (HBS) and STATA software, a special CPI for each household of the sample is extracted. Subsequently nominal expenditures are deflated by these special CPIs, and at last, Gini coefficients are extracted from real expenditures. Our findings indicate that in recent years, extracted Gini coefficients are remarkably higher than prevailing ones.
 

This paper investigates the behavior of the Y-shaped bracing system. Because of the special type of eccentricity in this system, the behavior of the frame is strongly dependent on the geometrical changes of the braces. So that even in the elastic region, it shows the geometrically nonlinear behavior. The amount of eccentricity is very effective on the nonlinear behavior of the frame. Also the ratio of cross sections of the bracing members has a very important impact on the expected performance of the frame. The results show that this system tolerates large displacements, and can act like a base isolation system. Firstly, using a two-dimensional accurate modeling related to the geometrical...