997 resultados para Hard part


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Ponent: Anna Ortiz / Presenta: Bárbara Biglia

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Ponent: Anna Ortiz / Presenta: Bárbara Bligia

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The motion instability is an important issue that occurs during the operation of towed underwater vehicles (TUV), which considerably affects the accuracy of high precision acoustic instrumentations housed inside the same. Out of the various parameters responsible for this, the disturbances from the tow-ship are the most significant one. The present study focus on the motion dynamics of an underwater towing system with ship induced disturbances as the input. The study focus on an innovative system called two-part towing. The methodology involves numerical modeling of the tow system, which consists of modeling of the tow-cables and vehicles formulation. Previous study in this direction used a segmental approach for the modeling of the cable. Even though, the model was successful in predicting the heave response of the tow-body, instabilities were observed in the numerical solution. The present study devises a simple approach called lumped mass spring model (LMSM) for the cable formulation. In this work, the traditional LMSM has been modified in two ways. First, by implementing advanced time integration procedures and secondly, use of a modified beam model which uses only translational degrees of freedoms for solving beam equation. A number of time integration procedures, such as Euler, Houbolt, Newmark and HHT-α were implemented in the traditional LMSM and the strength and weakness of each scheme were numerically estimated. In most of the previous studies, hydrodynamic forces acting on the tow-system such as drag and lift etc. are approximated as analytical expression of velocities. This approach restricts these models to use simple cylindrical shaped towed bodies and may not be applicable modern tow systems which are diversed in shape and complexity. Hence, this particular study, hydrodynamic parameters such as drag and lift of the tow-system are estimated using CFD techniques. To achieve this, a RANS based CFD code has been developed. Further, a new convection interpolation scheme for CFD simulation, called BNCUS, which is blend of cell based and node based formulation, was proposed in the study and numerically tested. To account for the fact that simulation takes considerable time in solving fluid dynamic equations, a dedicated parallel computing setup has been developed. Two types of computational parallelisms are explored in the current study, viz; the model for shared memory processors and distributed memory processors. In the present study, shared memory model was used for structural dynamic analysis of towing system, distributed memory one was devised in solving fluid dynamic equations.

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Semiclassical theories such as the Thomas-Fermi and Wigner-Kirkwood methods give a good description of the smooth average part of the total energy of a Fermi gas in some external potential when the chemical potential is varied. However, in systems with a fixed number of particles N, these methods overbind the actual average of the quantum energy as N is varied. We describe a theory that accounts for this effect. Numerical illustrations are discussed for fermions trapped in a harmonic oscillator potential and in a hard-wall cavity, and for self-consistent calculations of atomic nuclei. In the latter case, the influence of deformations on the average behavior of the energy is also considered.

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Supervision ist Beratung beruflichen Handelns. Zentrales Anliegen der Dissertation ist die Entwicklung der Arbeitswelt in der Moderne sowie die aktuellen Veränderungen näher zu beleuchten, um ihre Bedeutung für die Supervision zu eruieren. Vorab werden die Geschichte und Weiterentwicklung der Supervision mit ihren Spannungsfeldern skizziert. Der Hauptteil handelt von der Herausbildung und Durchsetzung der kapitalistischen Produktionsweise. Es wird dargelegt, was für ein vielschichtiger Prozess für den einzelnen und die Gesellschaft in Gang gesetzt wurde, um die moderne Wirtschaftsweise zu installieren und welche Unterstützung aus anderen Bereichen -Religion, Politik etc. - dazu von Nöten war. Darüber hinaus wird aufgezeigt, welche Konflikte von Anfang an vorhanden waren. Das Hauptaugenmerk richtet sich auf die Prämissen der modernen Arbeitswelt und die mögliche Inkompatibilität ihrer Anliegen: Gewinn und Gerechtigkeit, Konkurrenz und Kooperation, freier Markt und staatliche Regulation, Gleichheit und Spezialisierung, Individualität und Kollektivität. Konflikte und Verstrickungen, die sich daraus für den arbeitenden Menschen ergeben und somit Thema für die Supervision wurden, werden herausgearbeitet. In bezug auf Supervision wird dargestellt, welche Problematik der Wirtschaftsweise immanent ist und schwerlich durch Beratung aufgelöst werden kann. Eine bedeutsame Stellung nimmt die Arbeit als eine zentrale Kategorie der Ökonomie ein. Die Verflechtung von Arbeit und Ökonomie sowie der Entwicklungsverlauf von Arbeit werden skizziert: vom Fordismus zur Globalisierung. Beschrieben und erörtert werden die Konsequenzen für die aktuellen Arbeitsformen und -bedingungen durch die Produktivkraftentwicklung und die neuen Produktionskonzepte. Arbeit wird kritisch in ihrer Funktion für die kapitalistische Produktionsweise reflektiert, mit ihren Beeinträchtigungen für den tätigen Menschen. Das ambivalente Verhältnis von Mensch und Ökonomie wird als das signifikanteste Spannungsfeld für die Supervision betrachtet, verbunden mit der Herausforderung, Supervision nicht zu einer Beratungstechnologie zur Anpassung und Funktionalisierung des Menschen an die sich immer rascher verändernde Arbeitswelt zu zuschneiden.

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A detailed study of the electronic structure and bonding of the pentahalides of group 5 elements V, Nb, Ta, and element 105, hahnium (and Pa) has been carried out using relativistic molecular cluster Dirac-Slater discrete-variational method. A number of calculations have been performed for different geometries and molecular bond distances. The character of the bonding has been analyzed using the Mulliken population analysis of the molecular orbitals. It is shown that hahnium is a typical group 5 element. In a great number of properties it continues trends in the group. Some peculiarities in the electronic structure of HaCl_5 result from relativistic effects.

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Relativistic self-consistent charge Dirac-Slater discrete variational method calculations have been done for the series of molecules MBr_5, where M = Nb, Ta, Pa, and element 105, Ha. The electronic structure data show that the trends within the group 5 pentabromides resemble those for the corresponding pentaclorides with the latter being more ionic. Estimation of the volatility of group 5 bromides has been done on the basis of the molecular orbital calculations. According to the results of the theoretical interpretation HaBr_5 seems to be more volatile than NbBr_5 and TaBr_5.