Sharif Digital Repository

With the global oil price increase in recent years and fossil fuel resource scarcity, analyzing of fossil fuel consumer industries and optimization of their fuel consumption is an important rule. Exergy analysis is an efficient tool for this purpose in the chemical and petrochemical processes in recent years more than ever. Therefore, in this work, an exergy analysis is performed for heat recovery section of Steam-Methane Reforming (SMR) process as a major consumer of natural gas.
This work contains five general section. At the first section, exergy and energy concepts, reforming processes and other related basic concepts are described. The second section is about the recent research and... 

The most crucial physical component in human-robot interaction is the head of the robot, which may have the potential to interact via representing facial expressions. There are several different types of robotic heads. This thesis presents the design process and realization of a retro-projected social robotic head, “Taban”. Taban is a cost-effective portable robot with a lifelike robotic face which can produce different facial expressions, different 3D face animation avatars (ranging from different ages, races, and gender) with the help of rear-projector in its head to projects animations onto a translucent 3D printout mask. It has a neck system with two degrees of freedom, a camera in the... 

An impedimetric human papilloma virus (HPV) DNA biosensor based on gold nanotubes (AuNTs) in label free detection was materialized. The AuNTs decorated nanoporous polycarbonate (AuNTs-PC) template as biosensor electrode was fabricated by electrodeposition method. The single strand DNA (ss-DNA) probe was covalently immobilized onto the AuNTs-PC electrode. The hybridization of target sequences with the ss-DNA probe was observed by the electrochemical impedance spectroscopy (EIS). The biosensor showed high selectivity and could differentiate between the complementary, mismatch and non-complementary DNA sequences. The EIS measurements were matched to Randle's equivalent circuit. The... 

In contacts, the presence of both variable loading and low-amplitude movements causes a kind of fatigue in these components called FRETTING FATIGUE. fretting fatigue has reduced the life of parts. Due to the high cost of replacing some parts in case of failure, it is necessary to take effective measures to delay this exhaustion. One of the effective solutions that can be applied is the use of coating and surface treatments in the contact areas. In this research, first, the fretting fatigue maps of Ti-6Al-4V alloy have been calculated and drawn according to the recommendations of the ASTM standard by using finite element methods. In the next step, by using experimental experiments, the damage... 

A number of players are positioned on the vertices of a finite graph, and each is wearing a hat whose color has been randomly and equally likely selected from a finite set of colors. Player A sees Player B if and only if there is a directed edge from the vertex corresponding to A to the vertex corresponding to B. The players must agree on a specific strategy before the game begins and carry it out. Once the game begins, no communication is allowed between the players, and each player must simultaneously guess the color of their own hat. The team wins if at least one guess is correct. For a given directed graph, we define the 'guessing number' of the graph as the maximum number of colors for... 

People usually use trust and reputation when they encounter uncertainty in the nature. Graphs are good tools to model and analysis of trust’s problems. If we show human and computer agents by graph’s nodes and trust values by its edges, in literature, the output graph is so-called Web of Trust. Most recently, there are three major research areas in which trust is studied. First area is policy-based trust which uses policies, digital signature and authentication methods. Second area is reputation-based trust which uses reputation and social network tools to estimate trust where past interactions or performance for an entity are combined to assess its future behavior. Third area is trust... 

Peer-to-Peer networks are invented to enable participants (peers) to share their resources and find and use the shared resources of the others. So the main issue is the mechanism of finding granted resources of the other peers. In Peer-to-Peer networks, there is no central server to index shared resources of the peers. So peers should collaborate to provide a fully distributed mechanism for searching resources. Considering the huge size of peer-to-peer systems, it is apparent that efficiency of the search mechanism is very critical. In this thesis, to have efficient seach in Peer-to-Peer networks, we propose two approaches. Then based on these approaches, we propose the third approach to... 

With significant advances in software development technologies in recent years, it is possible to have complex software applications, wich include large number of heterogeneous software components distributed over a large network of computers with different computational capabilities. To run such applications, their components must be instantiated on proper hardware resources in their target environments so that all requirements and constraints are met and some quality of service parametesrs (e.g.,reliability, load balancing, etc) are also optimized. This process is called software deployment. For large, distributed ,component-based applications¬ with many constraints and requirements, it ...