Sharif Digital Repository

4E analysis is used on a Brayton-Rankine combined cycle power plant (CCPP) with a dual pressure heat recovery steam generation (HRSG) system. A multi-objective genetic-based evolutionary optimization has been used to estimate the most optimal exergy efficiency status, exergy cost reduction, carbon emission reduction, and NOx emission reduction. For the validation of the data, the simulation results are compared with the plant's data. This study investigates the effect of every decisive parameter on the objective performance parameters of the CCPP. The primary estimated results are the emission rates, efficiencies, and the exergoeconomic cost of the system. At the optimum operational state,... 

A new combined cooling and power (CCP) cycle is proposed by a novel combination of the Kalina cycle (KC) and ejector refrigeration cycle (ERC) to produce simultaneous power output and cooling output. The exhaust of the turbine is fed to the ejector as a primary flow to draw the secondary flow (outlet of the evaporator) into the ejector. Energy, exergy, and exergoeconomic analysis of the proposed cycle are carried out leading to determine the first-law-efficiency, the second-law-efficiency, the sum unit cost of the product (SUCP) of the system, and the main source of the irreversibility. The thermal efficiency, exergy efficiency, overall exergy destruction rate, SUCP of the system, net... 

Carbon nanotube webs exhibit interesting properties when used as thermo-acoustic projectors. This work studies thermo-acoustic effect of these sound sources both in near and far field regions. Based on two alternative forms of the energy equation, we have developed a straightforward formula for calculation of pressure field, which is consistent with experimental data in far field. Also we have solved full 3-D governing equations using numerical methods. Our three-dimensional simulation and experimental data show pressure waves are highly affected by dimensions of sound sources in near field due to interference effects. However, generation of sound waves in far field is independent of... 

In this paper, the performance of an internal combustion engine is evaluated at the steady-state condition by application of energy and exergy analysis using the experimental test results. The energy and exergy balances are calculated at different engine speeds. The results show that the heat rejection of energy and exergy flow increases with increasing engine speed. The exergy efficiencies are slightly higher than the corresponding energy efficiencies. The results of this study have revealed that the most important source of the system inefficiency is the destruction of exergy by irreversible processes, mostly by the combustion. One can conclude that the use of a combined energy and exergy... 

This article discusses a hexagonal prism rolling down an inclined plane, which is easy to realize experimentally and yields results that are consistent with a simple theory. This investigation would make an excellent undergraduate project. © 2009 American Association of Physics Teachers  

This paper presents energy analysis of multiple-cracked beams. The study deals with crack energy reduction functions for consuming strain energy due to crack growth and the degree of conformity between these functions and experimental results. Three different reduction functions are employed in this research work. A comprehensive analysis is performed providing a comparison of the functions for a beam with one and two cracks. In order to elucidate advantages and disadvantages of each function, we employ them in different crack detection problems. For different cases of crack localization and quantification in a crack detection problem, the best function that fits the experimental results... 

There are two strategies for deadlock handling in routing algorithms in NoC: deadlock avoidance and deadlock recovery. Some deadlock recovery routing algorithms are re-injection based, such as: Compressionless (CR), Software-Based (SW-TFAR) and AFBAR. In spite of the performance comparison, none of existing researches have focused on the energy consumption of various routing algorithms. We evaluate these routing algorithms according to their energy consumption and latency. Our experimental results show the better performance and worse energy consumption of deadlock recovery routing algorithms compared to deadlock avoidance routing algorithms. In addition, the best and worst energy... 

For many years, it has been a significant concern for nanoscience researchers to synthesize nanomachines with steerable motion. Despite the notable number of studies on the motion of nanocars on a surface, the motion characteristics of carbon nanotubes received less attention. Remarkable features such as symmetry, strength, and stiffness made carbon nanotubes (CNTs) a proper option as wheels in the nanocars. In this paper, for the first time, the motion of carbon nanotube on a gold substrate and its advantages over previous wheels such as fullerene and p-carborane are investigated. We demonstrate that contrary to the other wheels, CNT moves in a directed path, making them an ideal option as... 

In this paper, inspired by a gas turbine power plant, the interaction between plant-soil processes has been simulated. It is aimed to indicate that solar energy in the photosynthesis process is equivalent to the fuel in combustion chambers. In the glucose production process, when solar exergy is considered as a fuel, 99.4% of total exergy cost is supplied by solar exergy and only 0.6% of the exergy cost is provided by nutrients’ content. In general, 30% of the total exergy entering the Calvin cycle is consumed in glucose production and the remaining 70% is related to biomass generation (as flue gas in the gas turbine). Moreover, 98% of the total exergy cost of the soil box is related to... 

In this paper, a low energy yet reliable communication scheme for network-on-chip is suggested. To reduce the communication energy consumption, we invoke low-swing signals for transmitting data, as well as data encoding techniques, for minimizing both self and coupling switching capacitance activity factors. To maintain the communication reliability of communication at low-voltage swing, an error control coding (ECC) technique is exploited. The decision about end-To-end or hop-To-hop ECC schemes and the proper number of detectable errors are determined through high-level mathematical analysis on the energy and reliability characteristics of the techniques. Based on the analysis, the extended... 

The dynamics of a pressure regulator valve have been studied using the through Bondgraph simulation technique. This valve consists of several elements that can transmit, transform, store, and consume hydraulic energy. The governing equations of the system have been derived from the dynamic model. In solving system equations numerically, various pressure-flow characteristics across the regulator ports and orifices have been taken into consideration. This simulation study identifies some critical parameters that have significant effects on the transient response of the system. The results have been obtained using the MATLAB-SIMULINK environment. The main advantage of the proposed methodology... 

Energy methods such as Energy Flow and Statistical Energy Analyses have been popularly used to predict the medium to high frequency vibro-acoustic response of several structures. In these energy methods, usually the common simple structural theories are used for simplicity. Since, the effects of shear deformation and rotary inertia at high frequency regions are unavoidable, it is necessary to determine the validity of these theories in each frequency domain. This paper aims to propose a method for defining a criteria to select a proper structural theory based on the order of shear deformation and rotary inertia to be used in vibration analyses. Several common as well as higher-order beam...