Sharif Digital Repository

Air-cooled condenser is widely used in thermal power plants as its main cooling system. However, the thermal capacity of air-cooled condensers reduces considerably in environmental wind drafts. So, the purpose of this study is to find practicable solutions to minimize the mal-performance of air-cooled condensers in windy conditions in either design or off-design conditions and consequently prevent the related steam turbines power reduction. The target combined cycle power plant consists of 4*160 MW steam turbines and 4 air-cooled condensers in its steam cycle part. This research presents two general and practical remedies, which are also applicable to many different powerplants irrespective... 

One of the different methods of heat transfer, is pool boiling process. In this method, the operating fluid starts to boil on a hot surface whose temperature is more than boiling point of the fluid. Based on difference between between surface temperature and fluid boiling point, amount of heat flux from hot surface to fluid and fluid behavior will be different. In recent years, many researchers have tried to improve the amount of heat transfer in the boiling process by using various methods such as nanoparticle addition or using magnetic field.Latent heat is thermal energy released or absorbed, by a body or a thermodynamic system, during a constant-temperature process, usually a first-order... 

The purpose of present work is to study the effect of different parameters on the solar chimney used in ventilation. Experimental model and numerical model were used to achieve this goal. First, the model was numerically analyzed by Fluent software using Boussinesq approximation. The results of numerical modeling were validated by the empirical model. Finally, the numerical model can be used to investigate the effects of parameters which modeling is not possible by the empirical model for any reason. Experimental modeling was performed on a chimney with height and width of 180 and 62 cm, respectively. The thickness and angle of chimney in both experimental and numerical methods varied from 5... 

Carbon-based thin films possess low friction coefficient, low surface roughness, chemical inertness and outstanding biocompatibility. In the present work, TiO2 nanoparticles were covered by a thin film of pyrolytic carbon (PyC) to provide a core-shell morphology. The PyC film was deposited by dehydrogenation of methane in a fluidized bed chemical vapour deposition (FBCVD) reactor at 1100 °C. The prepared specimens were characterized by various analytical methods including XRD, SEM, TEM, AFM, TGA and contact angle measurement techniques. Biocompatibility profiles of the resulting materials were evaluated using MTT and cell cycle assay. The results showed that the thin carbon film strongly... 

The Quadriceps Muscle as one of the major muscles of the human body plays a key role in knee function. Strengthening of this muscle is recommanded to prevent knee pain and even cure some diseases. Many believe that by strengthening the medial part with respect to the lateral part of the quadriceps muscles, patellofemoral pain syndrome can be prevented or treated. In this regard, a muscle strengthening system, based on magneticorheological brake is designed which provides isometric, isotonic and isokinetic exercise of knee joint and also enables the selective muscle strengthening. Beforehand a musculoskeletal model of lower extremity is developed in OpenSim software, capable to estimate force... 

Truth and Method is one of the two or three most important works of this century on the philosophy of humanistic studies. The book is powerful, exciting, but undeniably difficult. Published when Gadamer was sixty, it gathers the ripe fruit of a lifetime's reading, teaching, and thinking. Because it is immersed in German philosophy and scholarship, the book is even more challenging for an American reader. An emerging body of commentary in English as well as the many shorter essays Gadamer has, happily, lived to write and which are increasingly available in translation provide additional means of access to his thought. Truth and Method, however, remains his magnum opus, the comprehensive and... 

The usual method for determination of pure component parameters of SAFT-type Equation of State (EoS) is to fit them to experimental vapor pressure and liquid density data. Since high-molecular-weight compounds, like polymers, do not have a detectable vapor pressure, there is a need for a predictive calculation method for parameters of polymers and other complex compounds. In 2008, Tihic et al. proposed a Group Contribution (GC) method for estimating molecular parameters of PC-SAFT EoS. In this thesis, it is attempted to extend the suggested method of Tihic et al. by adjusting molecular parameters of PC-SAFT EoS for about 120 new non-associating compounds using experimental data extracted...