HIGH PRESSURE PHENOMENA

Author: GONZÁLEZ NAVARRO SONIA.
Year: 2005.
University: MÁLAGA [www.uma.es].
Place of defense: E.T.S.I. INFORMÁTICA.
Place of preparation: E.T.S.I. INDUSTRIAL.

Summary: The motivation for this work has been based on the survey and design of a system VoD (Video low demand) that is scalable and economical. We chose a distributed architecture front of a centralized, mainly due to issues of scalability and fault tolerance. In this paper, we have proposed a distributed system of servers small capacity and low cost with partial replication, where only the most popular videos are stored on all servers. We have focused primarily on the study of algorithms resource planning that take into account the partial replication and any parameters that optimize the quality of distributed system. In addition, we have developed a mathematical tool that is useful for the designer has some guides to be able dimensional system. Specifically, we have developed an algorithm planning unicast (PRLS), which enables the sharing of the burden in the event that a server is overloaded. Moreover, we propose two multicast algorithms based strategies batching and patching with threshold (LTH and RLTH) who plan to efficiently all requests (local and remote) system distributed VoD proposed, so that waiting times they are small. Finally, we have proposed an algorithm that planned resources (BITM), which takes into account the impatience of users. This algorithm reduces the bandwidth usage while maintaining a dropout rate below a predetermined value. For all these algorithms we developed analytical models that allow us to measure the distributed system VoD, and we have made that have allowed simulations validate models and to study the influence of various parameters on the system performance.

Author: DÁVILA GARVÍN MARÍA JOSÉ.
Year: 2006.
University: BURGOS [www.ubu.es].
Place of defense: FACULTAD DE CIENCIAS.
Place of preparation: FACULTAD DE CIENCIAS.

Summary: The growing interest in the industrial processes involved in the multi substances (extraction, distillation, adsorption, leaching, etc.). Based, at least in part, the science of the balance of phases, are increasing the number of studies in the determination of properties termofísicas, making these the possibility of designing, improving and increasing the efficiency of these processes. This also enables predictive models that provide a quick, accurate and economical determination of the properties required by the industry. Besides being very important to obtain a comprehensive set of data from the various properties termofísicas pilot for the design of many industrial operations, this data set is used to obtain valuable information about the molecular structure of these systems, as well as on the various forces intermoleculares and structural factors that govern their behavior. This report gives a detailed description of the experimental techniques used in the laboratory Thermodynamics Area Physical Chemistry of the University of Burgos, such as determining the density and speed of sound in a wide range of pressure and temperature. To validate the techniques of measurement in accordance with the criteria of IUPAC was used as the test system-hexane, cyclohexane binary mixture, determining excess volumes, the viscosity mixing, the speed of sound mixing, the refractive index of mixture and excess heat capacity at constant pressure, excess partial molar volumes, partial molar volume at infinite dilution, activation energy of viscous flow of excess molar refraction, internal pressure and excess isothermal compressibility, in order to validate techniques of densimetría, viscosimetría, refractometry and calorimetry. Once validated each of the techniques described above, identified the same properties over and mix for binary systems MPN / (W, MeOH, CS2, NCP), PYR / (W, MeOH, MPN, NCP), NCP / (W, MeOH) W / MeOH, and the ternary systems MPN / PYR / (W, MeOH), PYR / RSC / (W, MeOH), NCP / MPN / (W, MeOH) and MPN / W / MeOH. The properties of excess and mixture is correlated with the equations Redlich-Kister the binary systems and Cibulka the ternary systems. In the study of liquid-liquid equilibrium (ELL) for the determination of the coordinates criticism used a corresponding equation, choosing binary N-metil-2-pirrolidona + n-hexane, as a system test. Once validated the technique ELL, identified coordinates criticism for binary systems MPN / (C6, C8, C10, cC6, cC8, 2-MP, 3-MP, 2,2-DMP, 2,3-DMP, 2,2,4 - TMP) and NCP / W, applying SAFT and PC-SAFT. In the development of this research work, has been established tuning protocol and use of systems for determining density (diagrams PVT), and velocity of sound in a broad range of pressure and temperature, this latest technique being developed in full in the laboratory of Thermophysics of Imperial College London (Ball, 2002). It was used for n-hexane as a reference liquid according to the criteria of the IUPAC, to 100 MPa and 373K. It identified diagrams PVTx for systems MPN / (W, MeOH, CS2) and PuTx for binary MPN / MeOH. Based on the results described in the preceding paragraph, and using measures of Cp in the same range of temperatures at atmospheric pressure, identified the coefficient of thermal expansion, and the isothermal compressibility, kT and densities at high pressure and temperature , the latter being compared with the results obtained experimentally. The molars were identified entalpías of former 8 cess pair 4df to the system MPN / Supercritical CO2 at various pressures and temperatures in the laboratory Balancing Supercritical Fluid Phases of the Complutense University of Madrid. Being experimental results correlated using the equation Padé. This will set up a design and measurement protocol for each technique to analyze our data with those established as a reference, so as to establish the accuracy of each technique and also justify any differences that may exist.