Sharif Digital Repository

Green tea has been receiving significant attention in recent years due to its high content of catechins; Epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC) and especially epigallocatechin gallate (EGCG). As powerful antioxidants, these compounds are believed to have several health benefits. In this study, we used supercritical CO2 with ethanol as co-solvent to extract catechin derivatives from green tea and we investigated the effects of experiment parameters on the extraction. Experiments, designed according to Taguchi algorithm, were conducted with green tea particles of four average diameters of 1500, 855, 605 and 427.5 µm, in an interval of 35- 55 ̊C for temperature and... 

Evaporation is the most important water loss from terminal lakes which can influence the chemistry of lakes. In large lakes, the spatial distributions of meteorological and water quality variables affect the evaporation rates. Therefore, it is crucial to consider such variations in estimating evaporation rates from large lakes. This study aims at developing an evaporation estimation model for saline lakes considering salinity and spatial distribution of variables in/over the lakes and investigating the interaction between meteorological, hydrological and water quality variables in natural saline systems. To accomplish these objectives, first a distributed model was developed for estimating... 

provide about 67% of a hospital’s profit. Hospital managers are interested in decreasing the costs as well as increasing the customers’ satisfaction level. In this Thesis, four Mixed- Integer Programming models for planning and scheduling operating rooms are proposed. In the main, the problem is presented in two phases. In The first phase, model assigns the date and the room to each surgical and in second phase the model determines the sequencing of the assigned operation cases. The effects of using three different scheduling strategies (Block and Open and modified block) for assigning operating rooms to surgeons on the planning of surgical cases is studied. Then we proposed one phase model... 

According to recent advancements in digital circuit technology and new constraints for digital systems, scholars have researched to find a replacement for traditional copper links that is used to connect the embedded processing elements in a chip. Optic NoCs and wireless NoCs are two promising solutions to overcome challenges in traditional NoCs.
In this thesis, an innovative 3D NoC architecture is proposed which consists of four 2D mesh-based networks and they are connected via four wireless sub-networks as backbones. It is estimated that, the proposed architecture shrinks the power consumption at least 35 percent relatively due to the gate-level simulations. Thus, a better scaling and... 

Nowadays, along with the increasing development of renewable energy sources such as solar and wind, the need to use cost-effective fixed energy storage systems with cyclic stability at high rates is increasing. Due to their abundance and high safety, aqueous rechargeable calcium-ion batteries have the potential to meet the growing needs of stationary energy storage devices. In addition, they can be produced at low cost and have a higher volume capacity. However, the electrochemical stability window, which is controlled by the hydrogen production reaction on the anode and the oxygen production reaction on the cathode, severely limits the application of electrode materials in aqueous... 

In a macro view point, it can be said that housing demand in recent years is making the construction industry one of the main sectors of Iran’s economy. On the other hand, analysis of seismic risk in the country with regard to the geological conditions, the faults, and the seismic records of mega city of Tehran is depicting the delicate location of the Iranian capital. This city is selected as a case study in this thesis that has a high probability for the event; where this event has also been classified as a devastating earthquake ever. Due to the involvement of private sector in construction industry, the need for establishing a system of strict control on quality of construction of the... 

In this paper we have tried to mention a proper method of upscaling permeability data in a typical Iranian reservoir. Firstly a literature review is made on some common upscaling methods witch have been used so far. We introduced common upscaling methods like full tensor method, streamline method, stone method , vertical equilibrium method and also Kyte & Berry method. Additionally we have explained their advantages and also disadvantages. After selecting two upscaling methods, Kyte & Berry method and vertical equilibrium method, we applied these algorithms for upscaling of permeability data of Soroosh Oil Field. Soroosh oilfield is a heavy oil, Iranian reservoir located in Persian Gulf.... 

Aerodynamics loads and aeroheating during reentry, are one of the challenging issues in designing One of the main challenges in the design and application of reusable spacecrafts is the aerodynamic and thermal loads acting on their structures during reentry into the atmosphere. For this reason, all the concepts/prototypes presented in the 20th century were either not fully reusable, or were partially canceled, or did not have economic justification. In this report, the aerodynamic loads on the first stage of a launch vehicle during the launch and return phases have been investigated. Due to the fact that the main part of the first stage of the vehicle includes fuel and oxidizer tanks, the...