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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

The renormalised quark mass in the Schrödinger functional of lattice QCD / a one-loop calculation with a non-vanishing background field

Kurth, Stefan 04 September 2002 (has links)
Diese Arbeit befasst sich mit störungstheoretischen Rechnungen zur renormierten Quarkmasse im Schrödinger-Funktional mit nicht verschwindendemHintergrundfeld. Als Grundlage der Rechnungen werden das Schroedinger-Funktional und seinegrundlegenden Eigenschaften erläutert. Auch die O(a)-Verbesserung, die zu einem schnelleren Erreichen des Kontinuumslimes fuehren soll, wird in diesem Zusammenhang dargestellt.Des weiteren wird erklärt, aufwelche Weise das Schrödinger-Funktional dazu dient, das Skalenverhaltenrenormierter Größen ueber einen grossen Energiebereich zuuntersuchen. Das Skalenverhalten sowohl der renormierten Kopplung als auchder renormierten Quarkmassen wird in diesem Schema durch Step-Scaling-Funktionenbeschrieben. Die Definition der renormierten Kopplung wird dargestellt,ebenso die Definition der renormierten Masse, die mit Hilfe derPCAC-Relation ueber den Axialvektorstrom und die Pseudoskalardichte erfolgt. Die Skalenabhängigkeit der renormierten Massewird auf die Skalenabhängigkeit der Renormierungskonstanten derPseudoskalardichte zurueckgefuehrt. Breiten Raum nimmt die Berechnung verschiedenerKorrelationsfunktionen bis zur Ein-Loop-Ordnung in Stoerungstheorie ein. Mit Hilfe der soermittelten Koeffizienten wird die kritische Quarkmasse, bei der die renormierte Masse verschwindet, in Ein-Loop-Naeherung berechnet,ebenso der Ein-Loop-Koeffizent der Renormierungskonstanten der Pseudoskalardichte. Mit Hilfe dieses Koeffizienten wird aus der bekanntenanomalen Dimension in Zwei-Loop-Ordnung im MS-bar-Schemadie anomale Dimension im Schrödinger-Funktional berechnet. Als weitere Anwendung der Störungstheorie werden verschiedene Diskretisierungsfehler bestimmt. Die kritische Quarkmasse in Ein-Loop-Ordnunggeht in den Zwei-Loop-Koeffizienten des Diskretisierungfehlers der Step-Scaling-Funktion der renormierten Kopplung ein, der durchdie Abweichung dieser Funktion von ihrem Kontinuumslimes definiert ist.Verschiedene Diskretisierungsfehler der Strommasse, die durch die PCAC-Relationmit unrenormiertem Axialvektorstrom und Pseudoskalardichte definiert ist, werdenin Ein-Loop-Ordnung berechnet. Ein wichtiger Diskretisierungsfehler derrenormierten Quarkmasse ist die Abweichung ihrer Step-Scaling-Funktion vomKontinuumslimes. Dieser Fehler ist in Ein-Loop-Ordnung bislang nur mitverschwindendem Hintergrundfeld bekannt und wird in dieser Arbeit mitnicht verschwindendem Hintergrundfeld berechnet. / The renormalised quark mass in the Schroedinger functional is studied perturbatively with a non-vanishing background field. The framework in which the calculations are done is the Schroedinger functional. Its definition and basic properties are reviewed and it is shown how to make the theory converge faster towards its continuum limit by O(a) improvement. It is explained how the Schroedinger functional scheme avoids the implications of treating a large energy range on a single lattice in order to determine the scale dependence of renormalised quantities. The description of the scale dependence by the step scaling function is introduced both for the renormalised coupling and the renormalised quark masses. The definition of the renormalised coupling in the Schroedinger functional is reviewed, and the concept of the renormalised mass being defined by the axial current and density via the PCAC-relation is explained. The running of the renormalised mass described by its step scaling function is presented as a consequence of the fact that the renormalisation constant of the axial density is scale dependent. The central part of the thesis is the expansion of several correlation functions up to 1-loop order. The expansion coefficients are used to compute the critical quark mass at which the renormalised mass vanishes, as well as the 1-loop coefficient of the renormalisation constant of the axial density. Using the result for this renormalisation constant, the 2-loop anomalous dimension is obtained by conversion from the MS-bar-scheme. Another important application of perturbation theory carried out in this thesis is the determination of discretisation errors. The critical quark mass at 1-loop order is used to compute the deviation of the coupling's step scaling function from its continuum limit at 2-loop order. Several lattice artefacts of the current quark mass, defined by the PCAC relation with the unrenormalised axial current and density, are computed at 1-loop order. An essential property of the renormalised quark mass being computed in this thesis at 1-loop order is the deviation of its step scaling function from the continuum limit, which was so far only known for the zero background field case.
42

On the chirally rotated Schrödinger functional with Wilson fermions

López, Jénifer González 13 July 2011 (has links)
Viele Phaenomene in der Natur sind eng verknuepft mit dem Niederenergieverhalten der QCD und damit von nicht-perturbative Natur. Viele Groeßen benoetigen auch eine nicht-perturbative Renormierung. Als nicht-perturbative Renormierungsschema schlagen wir das chiral gedrehte Schroedingerfunktional, χSF, in einer Gitterregularisierung vor. Auf dem Baumgraphenniveau wird eine analytische Rechnung im Kontinuum und auf dem Gitter durchgefuehrt. Weitere Untersuchungen werden dann in der Valenzquark-Approximation der Gitter QCD durchgefuehrt. Eines der Hauptziele ist es dabei, die im χSF benoetigten Koeffizienten nicht-perturbativ so einzustellen, dass ein wohl-definierter Kontinuumlimes durchgefuehrt werden kann. Es wird gezeigt, dass solch eine Feineinstellung der Parameter des χSF durchfuehrbar ist und dass physikalische Groeßen nicht sensitiv auf die spezielle Wahl der Bedingung zur Einstellung der Parameter sind. Es wird gezeigt, dass das Skalierungsverhalten physikalischer Groeßen konsistent mit fuehrenden O(a2) Diskretisierungseffekten ist. Das Hauptergebnis dieser Arbeit ist der Nachweis, dass das χSF mit den hier berechneten Verbesserungskoeffizienten, zu einem korrekten Kontinuumlimes fuehrt. Dazu wurden drei unterschiedliche Werte der Renormierungsskala verwendet und mehrere uns interessierende physikalische Groeßen berechnet. Wir koennen deshalb den Schluss ziehen, dass das χSF ein viel versprechendes Renormierungsschema darstellt, um eine nicht-perturbative Renormierung vorzunehmen und dabei gleichzeitig die automatische O(a)-Verbesserung aufrecht erhalten. Dies eroeffnet den sehr wichtigen Ausblick, dass das χSF in zukuenftigen nicht-perturbativen Berechnungen von Renormierungskonstanten auch ueber die Valenzquark-Approximation hinaus eingesetzt werden kann. / There are many phenomena in nature which are closely linked to the low energy regime of QCD. Theoretically, these can be dealt with only by means of non-perturbative methods. Often, a non-perturbative renormalization of QCD is required. We employ a 4-dimensional lattice as a regulator of QCD. As a non-perturbative renormalization scheme, we propose the chirally rotated Schrödinger functional, χSF. We perform analytical studies at tree-level of perturbation theory, in the continuum and on the lattice. Beyond tree-level, all studies are performed in the quenched approximation of QCD. One of the main targets has been to perform the non-perturbative tuning of the two required coefficients of the χSF scheme, such that a well defined continuum limit can be reached. We demonstrate that the tuning is feasible and physical quantities are insensitive to the tuning condition. There are also a couple of improvement counterterms at the boundaries. However, besides these boundary O(a) effects, the χSF is expected to be compatible with bulk automatic O(a)-improvement. We show that the scaling behavior of physical quantities is consistent with automatic O(a)-improvement. The other most important achievement has been to demonstrate that the χSF, with the here computed tuning coefficients, leads to the correct continuum limit. For this, we have performed universality tests of the continuum limit, at three different values of the renormalization scale and through the computation of several physical quantities of interest. The conclusion of these results is that the χSF is a promising scheme to perform non-perturbative renormalizations while maintaining bulk automatic O(a)-improvement. This opens the most relevant prospect that the χSF can be safely used in future non-perturbative computations of renormalization factors also beyond the quenched approximation.
43

Verbesserung kognitiver Leistungen bei chronischer Schizophrenie durch rekombinantes humanes Erythropoietin (rhEPO) / Improvement of cognitive functioning in chronic schizophrenia through recombinant human erythropoietin (rhEPO)

Aust, Susanne Carlotta 28 April 2008 (has links)
No description available.
44

Research on parliamentary privilege concurrently discuss Chinese National People's congressional privilege

Yi, Weizhong 23 September 2009 (has links)
Diese These ist über parlamentarische Privileg. Das Privile ist eine alte parlamentarische Macht. Alle Länder, die Demokratie durchgeführt haben oder bald haben, bestimmen parlamentarische Privileg in ihre Verfassungen. Der Zweck von Privileg ist, dass Abgeordneten die Meinung sowie ihre eigenen politische Position frei äußern zu shutzen, und sie brauchen nicht sich um Vergeltung von politischen Motiven zu sorgen. Das Parlament kann formulieren selbst die Geschäftsordnung und Disziplin des Parlamentes, damit das Parlament unabhängig sein kann, ihre Aufgaben frei erfüllen kann und seine Funktionen frei ausüben kann. Parlamentarische Privileg wird aber oft durch Publikum verkannt, die glauben, dass die Eliten der Gesellschaft eine besondere Schutze haben. Das ist ironisch. Weil Privileg der Abgordneten ursprünglich als Schutz des ganzen Parlamentes hergestellt warden. Damals schützt es Mitglieder des Parlaments vor den Eliten. Man kann sagen, dass die parlamentarische Privileg eine spezielle institutionelle Regelungen auf den Grundsätzen der Demokratie. Im Vergleich mit anderen parlamentarischen Befugnisse, ist es etwas Besonderes, weil es die Abwehrkraft des Parlaments nicht als eine offensive Kraft ist, die das Parlament aktiv ausüben muss. Nach der Erörterung der Stiftung in der Theorie der parlamentarischen Privilegien, diskutiert das Papier über die wichtigsten Elemente der parlamentarischen Privilegien, das Problem an der Praxis der parlamentarischen Privilegien und die Entwicklung der Privilegien . Schließlich erörtet die Dissertation, wie die entsprechenden Privilegien Systeme der chinesischen nationalen Volkskongress verbessert und vervollgekommen warden könne. / This thesis analyses parliamentary privilege. The privilege is an ancient parliamentary power. All of countries that have democratized or will soon have democratized provide them by own constitution. The purpose of the parliamentary privilege is to permit members of the legislature to speech freely and express their opinion of political position, and not worry about retaliation on the basis of political motives. The Parliament formulates itself its own rules of procedure and maintains the discipline of parliament itself and so on, in order to ensure that the parliament can independently, freely discharge of its duties and perform its functions. Parliamentary privilege, however, is often misunderstood by popular who believes that the privilege is the special protection of all of the elites of society. That is ironic, because privilege was originally produced as a whole of the protection of Parliament, and it protected members of parliament from the elites at that time. It may be said that parliamentary privilege is a special institutional arrangements based on the principles of democracy. Compared with other parliamentary powers, it is special because it is the defensive power of Parliament rather than an offensive power which the parliament must proactively exercise. After studying on the foundation in the theory of parliamentary privilege, the paper comprehensively discusses on the main elements of parliamentary privilege, the problems at the practice of parliamentary privilege and the development of privilege. Finally, it is to argument how to improve and perfect the relevant privilege systems of Chinese National People’s Congress.
45

Improving the predictive capability of the soil erosion modeling tool EROSION-3D: From observation data to validation

Lenz, Jonas 16 May 2023 (has links)
Ziel dieser Arbeit ist die Verbesserung der Vorhersagekraft des Bodenerosionsmodelierungs-werkzeugs EROSION-3D, welche oftmals durch die Identifizierung der werkzeugspezifischen Parameter Skinfaktor und Erosionswiderstand limitiert ist. Als drei Betrachtungsebenen der Arbeit werden 1. Beobachtungsdaten, 2. die Fähigkeit von EROSION-3D zur Beschreibung der Beobachtungsdaten und 3. die Vorhersagekraft des Werkzeugs untersucht. Aufzeichnungen verschiedener Beregnungsversuche wurden maschinenlesbar zusammengefasst. Daran wurde EROSION-3D mit den bisher üblichen sowie Monte-Carlo Methoden kalibriert. Anhand beschreibender Daten der Beregnungsversuche wurden Vorhersagemethoden zur Schätzung der modellspezifischen Parameter entwickelt und hinsichtlich der Parameterwerte und damit modellierter Abfluss-/Abtragswerte validiert. Die Ergebnisse zeigen, dass verbesserte Vorhersagen mit den neuen Schätzmethoden möglich sind, aber auch Möglichkeiten zur Verbesserung der Modellstruktur bestehen.
46

Cow Body Scan: Entwicklung der 3D-Bildanalyse zur Vermessung von Milchkühen und Vernetzung mit dem Herdenmanagementprogramm

Dorsch, Uwe, Schneider, Peter, Schäfer, Sebastian, Leuschke, Dirk, Paschold, Peter, Deißing, Franziska, Fischer, Ralf, Pache, Steffen 25 June 2024 (has links)
Die Schriftenreihe informiert über die Ergebnisse der experimentellen Entwicklung eines automatischen 3D-Bildanalysesystems zur Vermessung von Milchkühen und dessen Vernetzung mit dem Herdenmanagementprogramm, um den Milcherzeuger bei dessen Entscheidungen zu unterstützen. Im Rahmen des Verbundprojektes konnten wertvolle Erkenntnisse zu Möglichkeiten und Grenzen von 3D-Bildanalyseverfahren im Milchviehhaltungsbereich festgehalten und Lösungen für detektierte Problemstellungen gefunden werden. Durch die sichere, regelmäßige und objektive Erhebung von 3D-Daten wurde es möglich, in Form von Trendauswertungen die Entwicklung der Körperkondition darzustellen, Körpermaße stressfrei zu erheben und Ansätze für eine Gangbildanalyse zu entwickeln. Maßgeblich für den Erfolg von 3D-Bildanalyse-Verfahren in der Milchviehhaltung ist die Anbindung an eine Tiererkennung, die sich in ihrer aktuellen Struktur in Form von Insellösungen als größte Herausforderung darstellte. Die Veröffentlichung richtet sich an Praktiker, Bildung, Forschung & Entwicklung Redaktionsschluss: 07.11.2023
47

Improving capacity and design of water supply system for the case of Mazar-e-Sharif City

Yahyah, Mohammad Qaasim 15 November 2024 (has links)
In the world, improving quality and reliability of water supply systems, improving access to clean drinking water for the populations in conditions of development and intensive growth of urban settlements are considered an important issue. In this research the most important issue is improving the calculation methods of water delivery and distribution systems within urban water supply complexes. In most countries such as the USA, Germany, Russia, Israel, South Korea, China and other economically developed countries, special attention has been paid to provide clean drinking water for their population, improve the quality of design for water supply systems and ensure reliability and design of water distribution system for urban settlements. A water supply network for distributing the water for drinking and other purposes is a component of a city and municipal planning. Therefore, it needs to be planned and designed by city planners and civil engineers with the utmost care. It is also necessary to consider of factors that will have an impact, such as the location of the town or city, its current water demand, the growth in the demand in future, leakage in the systems, the required pressure in the pipes, losses in the pipes, etc. Targeted research aimed to develop scientifically grounded calculation methods for studying and developing theoretical bases for calculation water delivery and distribution system within urban water supply complexes. The study also considered new working conditions and requirements for their modernization, which are especially important worldwide. In this study the most important tasks are to improve calculation methods of water delivery and distribution systems under the condition of multi-mode water flow in pipes and uncertainties of network parameters. Further, Mazar-e-Sharif city has been considered as a case to apply the developed mathematical calculation, describing water delivery and distribution processes, rational development and reconstruction of water delivery and distribution systems. Currently, a wide range of comprehensive studies is being carried out in many countries on the use of modern computer technologies on the implementation of comprehensive measures to improve access to clean drinking water in city, through the construction of new water tanks, an extension of the existing water tanks, sewerage facilities and water supply network. The development strategy of the Islamic Republic of Afghanistan in line with SDG’s is first improving the supply and delivery of clean drinking water in each province of the country. Since many years the local Government of Balkh province and people of Mazar-e-sharif city are wishing to have the new modern water supply system to satisfy all needs but unfortunately, they did not success to get this opportunity. Mazar-e-Sharif is the second largest city in Afghanistan and the population is growing day by day as due to economic reasons people from other provinces immigrate to Mazar. The current water supply system is the individual/local distribution system made by the local community and some NGOs which are not standard, and the quality of the water is not satisfactory.:Table of Content CHAPTER 1 : Introduction 1 1.1 Background 1 1.2 Research Objectives 2 1.3 Structure of the thesis 3 1.4 Study Area 4 1.5 Socioeconomic conditions 5 1.6 Master Plan and Future Development 6 1.7 Physiography 7 1.8 Existing situation 8 1.8.1 Ground water 8 1.8.2 Water Quality 8 1.8.3 Surface Water 9 1.8.4 Actual Production 9 1.8.5 Storage 11 1.8.6 Operation of current Water Supply System 11 CHAPTER 2 : Literature review 13 2.1 Water Supply System 13 2.2 Water supply characteristics 15 2.3 Theory of hydraulic models 17 2.4 Analysis of existing theories and methodologies for modeling a water supply and distribution system in a water supply complex 31 CHAPTER 3 : Research methodology 36 3.1 Overview 36 3.2 Description of the properties and types of sets used in the model 38 3.3 Mathematical model of the water supply system 39 3.4 Mathematical model of the designed water supply network 41 3.5 Water flow continuity equation 43 3.6 Equation of water balance in tanks 44 3.7 Establishment of pressure loss in pipes, under the condition of optimal operation of tanks on the water supply system 44 3.8 The objective function of water supply network optimization 55 3.9 Limitations in optimizing the water supply network 58 3.10 Bringing distributed water consumption to network nodes of a water distribution system 60 3.11 Determination of rational parameters of a water distribution system 61 3.12 Determination of the parameters of water distribution system during the reconstruction of the existing water supply network 62 3.13 Mathematical model for optimizing the reconstruction of a water supply system 63 CHAPTER 4 : Result and Discussion 66 4.1 Assessment reliability of the results 66 4.2 Task 1 (Hydraulic calculation of a single-ring water supply network) 66 4.3 Task 2 (Hydraulic calculation of a multi-ring water supply network in simulation mode) 68 4.4 Task 3 (Test water supply network) 70 4.4.1 Water Demand 71 4.4.2 Parameters for Hydraulic Design 72 4.5 Design procedure 73 4.6 The structure of the software package and the model interface 83 4.6.1 Structure of the water supply optimization system 83 4.6.2 Optimization system control module 84 4.6.3 Graphical editor 84 4.7 Graphical editor input and output files 90 4.7.1 GDX file 90 4.7.2 Text file 90 4.8 EXCEL file 93 4.9 Water supply system indicators (pipe lengths, pipe diameters) 99 4.10 EXCEL file exists 100 CHAPTER 5 : Conclusion 109 CHAPTER 6 : References 112 CHAPTER 7 : Appendix 118 7.1 Diagram of the water supply network of a real settlement 118 7.2 Comparison of water flow rates in a real existing water supply network performed according to existing methods and using an optimization model in simulation mode 119 7.3 Comparison of the values of water consumption in the real existing water supply network performed according to existing methods and using the optimization model in the optimization mode 124 7.4 Compilation of pipe diameter in the real and optimal conditions in meters 129 7.5 Pressure in the nodes of the water supply network before connecting a new user and after connecting and reconstructing the network 135
48

How to increase the understanding of differentials by using the Casio-calculator model 9860 G I/II to solve differential equations

Bjørneng, Bjørn 12 April 2012 (has links) (PDF)
The major aims of this paper are to present how we can improve the students understanding and involvement in mathematics by using a programming/graphic calculator. I will use differentials as examples such as differentiation ,integrals and differential equations, creating lines of slopes for differential equation of the type y’= f(x,y) . Find the solution of some differential equations by using regression and create the graph connected to the differential equation. As we have different approaches to solving a problem, it is a hope the students interest in mathematics will improve. The tools used will be programming, graphic commands as plot, f-line, etc. One goal is also to show how we can create small programs solving problems in mathematics. For many students this will be a stepping stone for further work with programming. The programs used can be copied using the program FA 124 that can be downloaded from Casios homepages. On request I can send you the programs.
49

How to increase the understanding of differentials by using the Casio-calculator model 9860 G I/II to solve differential equations

Bjørneng, Bjørn 12 April 2012 (has links)
The major aims of this paper are to present how we can improve the students understanding and involvement in mathematics by using a programming/graphic calculator. I will use differentials as examples such as differentiation ,integrals and differential equations, creating lines of slopes for differential equation of the type y’= f(x,y) . Find the solution of some differential equations by using regression and create the graph connected to the differential equation. As we have different approaches to solving a problem, it is a hope the students interest in mathematics will improve. The tools used will be programming, graphic commands as plot, f-line, etc. One goal is also to show how we can create small programs solving problems in mathematics. For many students this will be a stepping stone for further work with programming. The programs used can be copied using the program FA 124 that can be downloaded from Casios homepages. On request I can send you the programs.
50

Parameter Study of Geometrically Induced Flow Maldistribution in Shell and Tube Heat Exchangers

Schab, Richard, Dorau, Tim, Unz, Simon, Beckmann, Michael 30 March 2023 (has links)
Shell and tube heat exchangers (STHEs) are the most common type of heat exchanger in preheat trains (PHT) of oil refineries and in chemical process plants. Most commercial design software tools for STHE assume uniform distribution over all tubes of a tube bundle. This leads to various challenges in the operation of the affected devices. Flow maldistribution reduces heat duty of STHE in many applications and supports fouling buildup in fluids that tend to particle, bio, and crystallization fouling (Verein Deutscher Ingenieure, ed., 2010, Heat Atlas, 2nd ed., VDI-Buch., Springer-Verlag). In this article, a fluid mechanics study about tube side flow distribution of crude oil and related hydrocarbons in two-pass PHT heat exchangers is described. It is shown that the amount of flow maldistribution varies significantly between the different STHE designs. Therefore, a parameter study was conducted to investigate reasons for maldistribution. For instance, the nozzles diameter, type, and orientation were identified as crucial parameters. In consequence, simple design suggestions for reducing tube side flow maldistribution are proposed.

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