Comparison results between Jacobi and other iterative methods

AbstractSome comparison results between Jacobi iterative method with the modified preconditioned simultaneous displacement (MPSD) iteration and other iterations, for solving nonsingular linear systems, are presented. It is showed that spectral radius of Jacobi iteration matrix B is less than that of several iteration matrices introduced in Liu (J. Numer. Methods Comput. Appl. 1 (1992) 58) under some conditions

Flow Field in a Novel Short Residence Time Gas-solid Separator

The gas flow field in a short residence time separator was investigated. The tangential velocity in the separator housing increases with increasing angle to the positive x axis, and decreases with increasing radial position. A swirl of opposite direction to the main current in the separator housing occurs in the gas outlet

The transformation and continuity of the traditional dwelling in Suzhou, China

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Architecture, 1992.Includes bibliographical references (p. 91-93).This thesis is a brief study of factors influencing the transformations of traditional housing and neighborhoods in the context of social change. It aims at clarifying permanence and change in the built environment and identifying the ways in which people express themselves in transforming their place of residence. This thesis examines how the residents of Suzhou transform their traditional courtyard house because of socio-economic change and modernization and yet retain some spatial and social patterns which are important to them. My purpose is to examine the neighborhoods with a positive eye, trying to select the good points and not just looking at what is wrong with it. How can creative involvement in the built environment be supported in the future? How can indigenous design solutions be encouraged. The courtyard houses in Suzhou have undergone many changes during the last four decades. The traditional courtyard house in Suzhou is a type of house that had slowly developed over more than two thousand years. At the beginning of the twentieth century it was still untouched by influences of the West and the industrial revolution. Though the first transformations of the Suzhou courtyard house occurred at the beginning of this century, the most important transformation happened during the last few decades. Due to socio-economic factors, such as the Cultural Revolution, the severe housing shortage, the courtyard house, once inhabited by one extended family, had to be shared among several families. New shelters had to be built in the traditional compound. Building materials and construction techniques also changed. The resulting living environment seems disordered at first sight. But underneath the messiness, the deployment of new additions and people's living patterns show some continuity of the traditional ways. The case study might reveal the traits that have continued to survive in the physical form and social patterns, despite all the complex changes in the society that time has inevitably caused. The case study exemplifies the continuity and transformations of the traditional dwelling environments in Suzhou. An attempt is made at the same time, to identify some basic principles and directions by which the architectural language of housing and urban form in such a study can be considered.by Chuan Wang.M.S

Operation Analysis on Refrigeration System Combined with Heat Pipe

In data center, telco equipment station and some central control rooms, there are some cases with cooling requirement all the year, their temperatures are usually controlled strictly whenever in summer or in winter. Moreover, due to clearness and safety requirement, the chiller should provide cooling water all the time even the outside environment is very cold. There had been some considerations about provide cooling capacity in cold climate with free environmental air by various heat exchangers directly. Without operating chillers, annual energy consumption on temperature control could be decreased. This paper proposed a system combined a chiller with an air-cooled heat exchanger, shown as Fig 1., there is one evaporator to provide cooled water, two condensers for the chiller and the separate type heat pipe alternatively. In warm climate, the chiller operates normally with the compressor and its condenser, the air cooling heat pipe is blocked by switching valves. In cold climate, the system is switched to the no compressor mode, the air-cooler heat exchanger could connect with the evaporator directly, the work pattern follows the separated type heat pipe, the working medium is the refrigerant still, the air cooling heat exchanger serves as the condenser of the separated type heat pipe, therefore, the evaporator is the evaporating part of the separated type heat pipe as well, the cooled water could be delivered through normal pipelines. In application of the combined refrigeration, they operation strategy for refrigeration and the heat pipe should be discussed in different climate zones. Therefore, in this paper we discussed energy consumption for cooling requirement in data center at several typical regions based on the combined cooling system. In different regions, their climates condition are different, the switching between the normal refrigeration and the heat pipe results to various annual energy consumptions

Tunable biphasic drug release from ethyl cellulose nanofibers fabricated using a modified coaxial electrospinning process

This manuscript reports a new type of drug-loaded core-shell nanofibers that provide tunable biphasic release of quercetin. The nanofibers were fabricated using a modified coaxial electrospinning process, in which a polyvinyl chloride (PVC)-coated concentric spinneret was employed. Poly (vinyl pyrrolidone) (PVP) and ethyl cellulose (EC) were used as the polymer matrices to form the shell and core parts of the nanofibers, respectively. Scanning and transmission electron microscopy demonstrated that the nanofibers had linear morphologies and core-shell structures. The quercetin was found to be present in the nanofibers in the amorphous physical status, on the basis of X-ray diffraction results. In vitro release profiles showed that the PVP shell very rapidly freed its drug cargo into the solution, while the EC core provided the succedent sustained release. Variation of the drug loading permitted the release profiles to be tuned

Nonlinear dynamics of hot, cold and bald Einstein-Maxwell-scalar black holes in AdS spacetime

We investigate the dynamical transition processes of an Einstein-Maxwell-scalar gravitational system between two local ground states and an excited state in the anti-de Sitter spacetime. From the linear perturbation theory, only the excited state possesses a single unstable mode, indicating the dynamical instability. Such an instability is associated with the tachyonic instability due to the presence of an effective potential well near the event horizon. From the nonlinear dynamics simulation, through the scalar field accretion mechanism, the critical phenomena in the transition process of the gravitational system between the two local ground states are revealed. The threshold of the accretion strength indicates the existence of a dynamical barrier in this transition process, which depends on the coupling strength between the scalar and Maxwell fields. On the other hand, for the unstable excited state, there exists a special kind of critical dynamics with a zero threshold for the perturbation strength. The perturbations of different signs push the gravitational system to fall into different local ground states. Interestingly, in an extended parameter space, there exist specific parameters such that the perturbations of non-zero amplitude fail to trigger the single unstable mode of the excited state