yes / This work describes how the design and operation parameters of the Multi-Stage Flash (MSF) desalination process are optimised when the process is subject to variation in seawater temperature, fouling and freshwater demand throughout the day. A simple polynomial based dynamic seawater temperature and variable freshwater demand correlations are developed based on actual data which are incorporated in the MSF mathematical model using gPROMS models builder 3.0.3. In addition, a fouling model based on stage temperature is considered. The fouling and the effect of noncondensable gases are incorporated into the calculation of overall heat transfer co-efficient for condensers. Finally, an optimisation problem is developed where the total daily operating cost of the MSF process is minimised by optimising the design (no of stages) and the operating (seawater rejected flowrate and brine recycle flowrate) parameters.

Yes / The need for desalinated seawater and reclaimed wastewater is increasing rapidly with the rising demands for drinkable water required for the world with continuously growing population. Reverse Osmosis (RO) processes are now among the most promising technologies used to remove chemicals from industrial effluents. N-nitrosamine compounds and especially N-nitrosodimethylamine (NDMA) are human carcinogens and can be found in industrial effluents of many industries. Particularly, NDMA is one of the by-products of disinfection process of secondary-treated wastewater effluent with chloramines, chlorines, and ozone (inhibitors). However, multi-stage RO processes with permeate reprocessing and recycling has not yet been considered for the removal of N-nitrosodimethylamine from wastewater. This research therefore, begins by investigating a number of multi-stage RO processes with permeate-reprocessing to remove N-nitrosodimethylamine (NDMA) from wastewater and finds the best configuration in terms of rejection, recovery and energy consumption via optimisation. For the first time we have applied Species Conserving Genetic Algorithm (SCGA) in optimising RO process conditions for wastewater treatment. Finally, permeate recycling is added to the best configuration and its performance is evaluated as a function of the amount of permeate being recycled via simulation. For this purpose, a mathematical model is developed based on the solution diffusion model, which is used for both optimisation and simulation. A number of model parameters have been estimated using experimental data of Fujioka et al. (Journal of Membrane Science 454 (2014) 212–219), so that the model can be used for simulation and optimisation with high accuracy and confidence.

Governments in many counties are taking measures to promote electric vehicles. An important strategy is to build enough charging infrastructures so as to alleviate drivers’ range anxieties. To help the governments make plans about the public charging network, we propose a multi-stage stochastic integer programming model to determine the locations and capacities of charging facilities over finite planning horizons. We use the logit choice model to estimate drivers’ random choices towards different charging stations nearby. The objective of the model is to minimize the expected total cost of installing and operating the charging facilities. Two simple algorithms are designed to solve this model, an approximation algorithm and a heuristic algorithm. A branch-and-price algorithm is also designed for this model, and some implementation details and improvement methods are explained. We do some numerical experiments to test the efficiency of these algorithms. Each algorithm has advantages over the CPLEX MIP solver in terms of solution time or solution quality. A case study of Oakville is presented to demonstrate the process of designing an electric vehicle public charging network using this model in Canada. / Thesis / Master of Science (MSc)

Organosilicon compounds, which are heavily utilized in personal care products, are typically present, sometimes in high concentrations in the influent of wastewater treatment facilities. During anaerobic sludge digestion, these compounds volatilize and enter the methane gas recovery stream. As the methane is combusted for energy cogeneration, these compounds become oxidized to microcrystalline silicon dioxide and cause damage and potential failure of expensive infrastructure. Adsorption and other catchment methods are typically utilized for removal of these volatilized compounds in order to mitigate their entrance into methane combustion systems. This research investigated the effect of phased anaerobic digestion, specifically acid-gas digestion, on the behavior of the volatilization of these organosilicon compounds, particularly octamethylcyclotetrasiloxane (D4) and decamethylcyclopentasiloxane (D5) as these are the most abundant volatile silicone compounds present in sludge. A bench scale acid reactor anaerobic digester was operated at varying solids retention times and temperatures in order to quantify biogas effects generated in the downstream gas reactor, which was operated at a constant mesophilic conditions. Results of the research indicated that the addition of an acid reactor did not cause a change in behavior of the D4 and D5 siloxane volatilization in the downstream gas reactor. However, it was observed that hydrogen sulfide gas was decreased in the gas reactor when an acid reactor was utilized, which could permit decreased corrosivity of biogas recovery. Cumulative volatile solids reduction and gas reactor methane yield data did not indicate an enhancement due to utilization of acid-gas digestion. / Master of Science

Thesis (PhD)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The aims of this thesis are to identify all possible modes of operaton for a multi-stage axial flow compressor; then to characterise the performance, attempt to numerically model operation, and determine the main flow field features for each mode. Four quadrant axial flow compressor operation occurs when the direction of flow through the compressor or the sign of the pressure difference across the compressor reverses, or any combination of these. Depending on the direction of rotation of the compressor, six modes of operation are possible in the four quadrants of the performance map. The rotor rotates in the design direction for three modes, and in the opposite direction for the other three. The stationary-rotor pressure characteristic is S-shaped and passes through the second and fourth quadrants. A three-stage axial flow compressor operating in the incompressible flow regime was used for the experimental investigation. Flow through the compressor was reversed or augmented by means of an auxiliary axial flow fan. Compressor performance was measured by means of static pressure tappings, a turbine anemometer calibrated to measure forward and reversed volumetric flow and a load cell for torque measurement. The inter-blade row flow fields were measured with pneumatic probes and 50 μm cylindrical hot film probes. Three dimensional single blade-passage Navier-Stokes simulations were performed using the Numeca FineTurbo package. Steady state simulations used a mixing plane approach. A nonlinear harmonic approximation was used for time-unsteady simulations. Unstalled first quadrant operation was unremarkable, and good agreement was obtained between experimental and numerical data. A single stall cell was detected experimentally during stalled operation, which was not modelled numerically. In the fourth quadrant for positive rotation, (windmilling), the compressor acts as an inefficient turbine. Flow separates from the pressure surface of the blade, rendering the steady-state mixing plane approach unsuitable. The performance characteristic curves for second quadrant for positive rotation, are discontinuous with those of first quadrant operation. The temperature rise in the working fluid is significantly higher than at design point. Periodic flow structures occurring across two blade passages were detected at all flow coefficients investigated, invalidating numerical modelling assumptions. Better agreement was obtained between experimental and numerical data from a case found in literature. If the compressor operates as a compressor in reverse (third quadrant operation), significant separation occurs on the pressure surface of all blades, and flow conditions resemble severe first quadrant stall. Separation becomes less severe at larger flow rates, allowing numerical simulation, though this is sensitive to the initial flow field. In the the part of the second quadrant, where the compressor rotates in reverse, it operates as a turbine. The blade angles and the direction of curvature match the flow angles and turning well, leading to high turbine efficiencies. Numerical simulations yielded good agreement with measured results, but were again sensitive to the initial flow field. Fourth quadrant operation with negative rotation occurs when flow is forced through the compressor in the design direction. Large separation bubbles are attached to the pressure surfaces of rotor and stator blades, so virtually all throughflow occurs near the hub and casing / AFRIKAANSE OPSOMMING: Die doelwitte van hierdie tesis is om al die moontlike werkmodusse vir ’n bestaande multi-stadium aksiaalvloei kompressor uit te ken; om dan die gedrag te gekarakteriseer, ’n poging aan te wend om die werking numeries te modelleer, en die belangrikste vloeiveldkenmerke vir elke modus te bepaal. Vier-kwadrant aksiaalvloei kompressor werking vind plaas as die rigting van die vloei deur die kompressor, of die teken van die drukverskil oor die kompressor omkeer, of enige kombinasie daarvan. Afhangende van die rigting van rotasie van die kompressor is ses operasionele modusse moontlik in die vier kwadrante van die kompressorkaart. Die rotor draai in die ontwerprigting vir drie van die modes, en in die teenoorgestelde rigting vir die ander drie. Die stilstaande-rotor drukkarakteristiek is S-vormig gaan deur die tweede en vierde kwadrante. ’n Drie-stadium onsamedrukbare vloei aksiaalvloei kompressor is vir die eksperimentele ondersoek gebruik. Vloei deur die kompressor is omgekeer of aangehelp deur middel van ’n aksiaalvloei hulpwaaier. Kompressor werking is gemeet deur middel van statiese druk meetpunte in die omhulsel, ’n turbine anemometer wat gekalibreer is om vorentoe en omgekeerde volumetriese vloei te meet, en ’n lassel vir wringmoment meting. Interlemryvloeivelde is opgemeet met pneumatiese sensors en 50-μm silindriese warm film sensors. Drie-dimensionele Navier-Stokes simulasies is uitgevoer vir ’n enkele lem van elke lemry, met behulp van die Numeca FineTurbo sagtewarepakket. ’n Mengvlakbenadering is gebruik vir bestendige toestand simulasies, terwyl ’n nie-linere harmoniese benadering gebruik is vir die tyd-afhanklike simulasies. Ongestaakte eerste kwadrant werking was alledaags, en goeie ooreenkoms is gevind tussen die eksperimentele en numeriese data. ’n Enkele staak-sel is eksperimenteel ontdek tydens gestaakte werking. Gestaakte werking is nie numeries gemodelleer nie. In die vierde kwadrant vir positiewe rotasie, (”windmeulwerking”), werk die kompressor as ’n ondoeltreffende turbine. Vloei-wegbrekinging op die lem drukoppervlaktes maak die bestendige toestand mengvlakbenadering ongeskik. In die kenlyne vir tweede kwadrant positiewe rotasie, is daar ’n diskontinu¨ıteit in die prestasie karakteristiekkrommes vir die eerste en tweede kwadrant werking. Die temperatuurstyging in die werk- vloeistof is beduidend ho¨er as as by die ontwerppunt. Periodiese vloeistrukture wat oor twee lemme plaasvind is gevind by alle vloei ko¨effisi¨ente wat ondersoek is, en dit maak die numeriese modellering aannames ongeldig. Beter ooreenkoms tussen die eksperimentele en numeriese data iss verkry met ’n geval wat uit die literatuur gevind is. Indien die kompressor werk as ’n kompressor in omgekeerde (derde kwadrant weking), vind beduidende wegbreking op die drukoppervlak van al die lemme plaas, wat lyk soos ernstige gestaakte eerste kwadrant werking. Die vloeiskeiding raak minder ernstig by ’n groter vloeitempo, wat numeriese nabootsing toelaat, maar die nabootsings is sensitief vir die aanvanklike vloeiveld. In die tweede kwadrant, by omgekeerde rotasie, werk die kompressor as ’n turbine. Die lemhoeke en die rigting van lemkromming stem ooreen met die vloeihoeke en verwringing, wat lei tot ho¨er turbine doeltreffendheid. Numeriese nabootsings stem goed ooreen met gemete resultate, maar is weereens sensitief vir die keuse van die aanvanklike vloeiveld. Vierde kwadrant werking met negatiewe rotasie vind plaas wanneer die lug gedwing word om deur die kompressor in die ontwerprigting te vloei. Groot skeidingborrels sit vas aan die drukoppervlaktes van alle lemme, sodat meeste deurvloei naby die naaf en die omhulsel plaas vind.

This bachelor thesis deals with the basic criminal activities of the police department by examining the crime scene in the conditions of the basic unit of the Police of the Czech Republic. The first part of the thesis deals with the examination in general, its types and principles. The second part concerns the division of the crime scene investigation by subject matter between the basic police unit and the Criminal Police and Investigation Service. The third part deals with the actual investigation of the crime scene, namely its concept, purpose, procedures and stage of investigation. The fourth part describes the crime scene documentation. The fifth part focuses on the conditions and problems in examining the crime scene performed by the basic body. Key words rowing, rowing ergometer, endurance, methods of endurance testing, Cooper test, Multi stage shuttle run

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No. of bitstreams: 1 4.pdf: 2382758 bytes, checksum: 4c6120c8307739a15287afe6bbb8a4e0 (MD5) Previous issue date: 2010-06 / UNISINOS - Universidade do Vale do Rio dos Sinos / PRÓ SINOS - Consórcio Público de Saneamento Básico da Bacia Hidrográfica do Rio dos Sinos / COMITESINOS - Comitê de Gerenciamento da Bacia Hidrográfica do Rio dos Sinos / FNMA - Fundo Nacional de Meio Ambiente do Ministério do Meio Ambiente / SEMA - Secretaria Estadual de Meio Ambiente do Rio Grande do Sul / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Este trabalho fundamentou-se no monitoramento de um sistema composto de três Biofiltros Aerados Submersos (BAS)multi-estágio, aplicado ao pós-tratamento de efluente de reator anaeróbio alimentado com mistura de lixiviado de aterro sanitário e esgoto doméstico, sendo testados três diferentes meios suporte: tampas e gargalo de garrafa PET, pedra britada nº4 e anéis Pall, sendo denominados BAS 1, 2 e 3. Os BAS são reatores com biomassa fixa, de forma que os microrganismos se aderem ao meio suporte formando biofilme. Neste sentido, este trabalho objetivou verificar a ocorrência de microbiota nitrificante no período de partida do sistema, convencionado em 90 dias. Foi avaliada a presença de bactérias nitrificantes através de técnicas de reação em cadeia da polimerase (PCR) e técnica do número mais provável (NMP), visando a quantificação dos microrganismos, especificamente Nitrosomonase Nitrobacter. A presença destes foi confirmada pelos resultados das análises físico-químicas e pela técnica de NMP.A contagem de bactérias do gênero Nitrosomonas para os 3 BAS apresentou um perfil semelhante com valores entre 7,8 x 101 e >1,6 x 105(BAS1); 7,8 x 101e 1,6 x 105(BAS2) e 2,4 x 101e 9,2 x 104(BAS3). O mesmo comportamento foi observado para bactérias do gênero Nitrobacter, cujos valores variaram entre: < 1,8 x 101e 1,6 x 104(BAS1); 1,8 x 101e 2,4 x 103(BAS2); 1,7 x 01e 3,5 x 103 (BAS3). As contagens de bactérias do gênero Nitrobacter apresentaram-se menores em todos os reatores. Os teores de nitrato avaliados no efluente mostraram a ocorrência de um acréscimo na concentração ao longo do período monitorado em todos os reatores apresentando os seguintes valores: 74 a 922 mg/L (BAS 1), 95 a 910 mg/L (BAS 2) e 33 a 910 mg/L (BAS 3), o que pode ser relacionado com o aumento da presença de bactérias nitrificantes, conforme resultados do NMP. As análises de PCR, entretanto, foram prejudicadas possivelmente pela presença de substâncias inibidoras dificultando a amplificação. Neste estágio toda a matéria orgânica facilmente biodegradável já havia sido consumida pelo pré-tratamento anaeróbio a jusante dos BAS, permanecendo no afluente aos BAS apenas matéria orgânica recalcitrante, o que dificultou o desenvolvimento de um biofilme adequado e possivelmente a amplificação do DNA das bactérias nitrificantes presentes no sistema. Esta pesquisa é parte de dois projetos amplos, o Programa de Apoio ao Ensino e a Pesquisa Científica e Tecnológica em Engenharias (Pró-Engenharias) e o Plano Sinos, que tem por objetivo estruturar o Plano de Bacia para o Rio dos Sinos. A importância deste trabalho vai de encontro com a necessidade de se desenvolverem alternativas que busquem melhorar a qualidade das águas residuárias lançadas na Bacia Hidrográfica do Rio dos Sinos. / his work was based on the monitoring of a system formed by three multi-stage Submerse Aerated Biofilters (BAS), applied to the post-treatment of effluent of the anaerobic reactor fed with mixture of landfill leachate and domestic sewage, being tested three different support media: lids and necks of PET bottles, broken stone nº4 and Pall rings, being denominated BAS 1, 2 and 3. The BAS are reactors with fixed biomass, in a way that the microorganisms adhere to the support media forming biofilm. In this way, this work had as objective to verify the occurrence of nitrifying microbiota in the set-off period of the system, established in 90 days. The presence of nitrifying bacteria was evaluated through polymerase chain reaction techniques (PCR) and technique of the most probable (NMP), seeking the quantifying of the microorganisms, specifically Nitrosomonas and Nitrobacter. The presence of these was confirmed by the results of the physical-chemical analysis and by the NMP technique. The counting of the bacteria of the Nitrosomonas gender for the 3 BAS presented a similar profile with values between 7,8 x 101 and >1,6 x 105(BAS1); 7,8 x 101 and 1,6 x 105(BAS2) and 2,4 x 101 and 9,2 x 104(BAS3). The same behavior was observed for bacteria of the Nitrobacter gender, which values vary between: < 1,8 x 101 and 1,6 x 104(BAS1); 1,8 x 101 and 2,4 x 103(BAS2); 1,7 x 101 and 3,5 x 103 (BAS3). The counting of bacteria of the Nitrobacter gender presented themselves lower in all the reactors. The levels of nitrate evaluated in the effluent showed the occurrence of an increase in the concentration during the monitored period in all the reactors presenting the following values: 74 to 922 mg/L (BAS 1), 95 to 910mg/L (BAS 2) and 33 to 910 mg/L (BAS 3), which can be related to the increase of the presence of nitrifying bacteria, according to the results of the NMP. The analysis of PCR, however, was harmed possibly by the presence of hindering substances making the amplification difficult. In this stage all the easily biodegradable organic matter had already been consumed by the anaerobic pre-treatment previously to the BAS, remaining in the affluent to the BAS only recalcitrant organic matter, which hindered the development of an adequate biofilm and possibly the amplification of the DNA of the nitrifying bacteria present in the system. This research is part of two more ample projects, the Teaching Aid Program and the Scientific and Technological Research in Engineering (Pro-Engineering) and the Sinos Plan, which has as objective to structure the Basin Plan for the Sinos River. The importance of this work meets the necessity of developing alternatives which seek to improve the quality of the wastewater thrown in the Hydrographic Basin of the Sinos River.

Ce travail de thèse, réalisé dans le cadre d’une collaboration avec la société Hispano-Suiza (groupe SAFRAN) porte sur la modélisation et l’analyse des vibrations et surcharges dynamiques sur les engrènements d’un réducteur aéronautique multi-étage constitué de plusieurs cascades d’engrènements situés dans des plans décalés. Une modélisation originale est proposée qui repose sur le couplage entre la résolution des équations du mouvement et la prise en compte des conditions de contact instantanées sur l’ensemble de tous les engrènements. Le modèle gère les phases relatives entre engrènements ainsi que l’influence des modifications de corrections de forme des dentures. En s’appuyant sur de nombreux exemples d’application, il est montré que des corrections de profil linéaires et symétriques adaptées permettent d’abaisser très sensiblement le niveau de surcharges dynamiques sur une plage de vitesse de rotation importante. Il est également confirmé que les efforts dynamiques sur les engrènements sont fortement corrélés aux amplitudes des variations temporelles des erreurs de transmission locales pour un fonctionnement quasi-statique sous charge. Considérant différentes architectures de transmissions, des optimisations conduites grâce à un algorithme génétique montrent que les paramètres optimaux de corrections de profil sont à choisir au voisinage d’une ‘courbe maîtresse modifiée’, initialement définie pour un seul engrènement et dont les propriétés semblent pouvoir être extrapolées à des systèmes avec plusieurs engrènements simultanés. Les résultats de simulations prouvent que l’ensemble des corrections sélectionnées sur les courbes maîtresses modifiées améliorent sensiblement le comportement dynamique des systèmes d’engrenages multi-étages. En revanche, pour des systèmes soumis à des niveaux de charge différents, des corrections optimales courtes semblent plus adaptées en termes de dynamique de l’engrènement tandis que des corrections optimales longues semblent plus efficaces en ce qui concerne le niveau de contraintes en pied de dents. / This research work, conducted in cooperation with Hispano-Suiza (SAFRAN group), is focused on the modelling and analysis of vibrations and dynamic loads in aeronautical multi-mesh gears comprising several spatial gear arrangements (idler gears, several pinions on one shaft). An original model is presented which relies on the simultaneous solution of the equations of motion and the instant contact conditions for all the tooth contacts and all the meshes. The phasing between the various meshes along with tooth shape modifications are integrated in the simulations. Based on a number of simulation results, it is shown that linear symmetric profile modifications can substantially reduce dynamic tooth loads over of broad range of speeds. It is also confirmed that dynamic mesh forces are strongly correlated with the time-variations amplitudes of local quasi-static transmission errors under load. Considering several gear arrangements, tooth profile optimisations have been performed using a genetic algorithm which indicate that optimum reliefs always lie in the vicinity of the so-called ‘modified Master Curve’ initially defined for a single pinion-gear pair. This finding suggests that the concept of Master Curve can probably be extended to more complex gear systems. The simulation results prove that all the optimal profile modifications on the Master Curve improve the dynamic tooth loading conditions in multi-mesh gears. However, for systems submitted to several load levels, short optimal reliefs seem preferable whereas long optimal reliefs are more effective in terms of root stresses.

The ability to produce potable water economically is the primary focus of seawater desalination research. There are numerous methods to desalinate water, including reverse osmosis, multi-stage flash distillation, and multi-effect evaporation. These methods cost more than potable water produced from natural resources; hence an attempt is made in this research project to produce potable water using a modified high-efficiency jet ejector in vapor-compression distillation. The greater efficiency of the jet ejector is achieved by properly mixing propelled and motive streams. From experiments conducted using air, the pressure rise across the jet ejector is better in case of one or two mixing vanes and the highest back pressure (pinch valve closed 83.33%). At other pinch valve closings, the air velocity through the jet ejector was high, so the extra surface area from the mixing vanes caused excessive friction and lowered the efficiency.

In 1915, Alfred Wegener published his hypotheses of plate tectonics that revolutionised the world for geologists. Since then, many scientists have studied the evolution of continents and especially the geologic structure of orogens: the most visible consequence of tectonic processes. Although the morphology and landscape evolution of mountain belts can be observed due to surface processes, the driving force and dynamics at lithosphere scale are less well understood despite the fact that rocks from deeper levels of orogenic belts are in places exposed at the surface. In this thesis, such formerly deeply-buried (ultra-) high-pressure rocks, in particular eclogite facies series, have been studied in order to reveal details about the formation and exhumation conditions and rates and thus provide insights into the geodynamics of the most spectacular orogenic belt in the world: the Himalaya. The specific area investigated was the Kaghan Valley in Pakistan (NW Himalaya). Following closure of the Tethyan Ocean by ca. 55-50 Ma, the northward subduction of the leading edge of India beneath the Eurasian Plate and subsequent collision initiated a long-lived process of intracrustal thrusting that continues today. The continental crust of India – granitic basement, Paleozoic and Mesozoic cover series and Permo-Triassic dykes, sills and lavas – has been buried partly to mantle depths. Today, these rocks crop out as eclogites, amphibolites and gneisses within the Higher Himalayan Crystalline between low-grade metamorphosed rocks (600-640°C/ ca. 5 kbar) of the Lesser Himalaya and Tethyan sediments. Beside tectonically driven exhumation mechanisms the channel flow model, that describes a denudation focused ductile extrusion of low viscosity material developed in the middle to lower crust beneath the Tibetan Plateau, has been postulated. To get insights into the lithospheric and crustal processes that have initiated and driven the exhumation of this (ultra-) high-pressure rocks, mineralogical, petrological and isotope-geochemical investigations have been performed. They provide insights into 1) the depths and temperatures to which these rocks were buried, 2) the pressures and temperatures the rocks have experienced during their exhumation, 3) the timing of these processes 4) and the velocity with which these rocks have been brought back to the surface. In detail, through microscopical studies, the identification of key minerals, microprobe analyses, standard geothermobarometry and modelling using an effective bulk rock composition it has been shown that published exhumation paths are incomplete. In particular, the eclogites of the northern Kaghan Valley were buried to depths of 140-100 km (36-30 kbar) at 790-640°C. Subsequently, cooling during decompression (exhumation) towards 40-35 km (17-10 kbar) and 630-580°C has been superseded by a phase of reheating to about 720-650°C at roughly the same depth before final exhumation has taken place. In the southern-most part of the study area, amphibolite facies assemblages with formation conditions similar to the deduced reheating phase indicate a juxtaposition of both areas after the eclogite facies stage and thus a stacking of Indian Plate units. Radiometric dating of zircon, titanite and rutile by U-Pb and amphibole and micas by Ar-Ar reveal peak pressure conditions at 47-48 Ma. With a maximum exhumation rate of 14 cm/a these rocks reached the crust-mantle boundary at 40-35 km within 1 Ma. Subsequent exhumation (46-41 Ma, 40-35 km) decelerated to ca. 1 mm/a at the base of the continental crust but rose again to about 2 mm/a in the period of 41-31 Ma, equivalent to 35-20 km. Apatite fission track (AFT) and (U-Th)/He ages from eclogites, amphibolites, micaschists and gneisses yielded moderate Oligocene to Miocene cooling rates of about 10°C/Ma in the high altitude northern parts of the Kaghan Valley using the mineral-pair method. AFT ages are of 24.5±3.8 to 15.6±2.1 Ma whereas apatite (U-Th)/He analyses yielded ages between 21.0±0.6 and 5.3±0.2 Ma. The southern-most part of the Valley is dominated by younger late Miocene to Pliocene apatite fission track ages of 7.6±2.1 and 4.0±0.5 Ma that support earlier tectonically and petrologically findings of a juxtaposition and stack of Indian Plate units. As this nappe is tectonically lowermost, a later distinct exhumation and uplift driven by thrusting along the Main Boundary Thrust is inferred. A multi-stage exhumation path is evident from petrological, isotope-geochemical and low temperature thermochronology investigations. Buoyancy driven exhumation caused an initial rapid exhumation: exhumation as fast as recent normal plate movements (ca. 10 cm/a). As the exhuming units reached the crust-mantle boundary the process slowed down due to changes in buoyancy. Most likely, this exhumation pause has initiated the reheating event that is petrologically evident (e.g. glaucophane rimmed by hornblende, ilmenite overgrowth of rutile). Late stage processes involved widespread thrusting and folding with accompanied regional greenschist facies metamorphism, whereby contemporaneous thrusting on the Batal Thrust (seen by some authors equivalent to the MCT) and back sliding of the Kohistan Arc along the inverse reactivated Main Mantle Thrust caused final exposure of these rocks. Similar circumstances have been seen at Tso Morari, Ladakh, India, 200 km further east where comparable rock assemblages occur. In conclusion, as exhumation was already done well before the initiation of the monsoonal system, climate dependent effects (erosion) appear negligible in comparison to far-field tectonic effects. / Seit der von Alfred Wegener 1915 postulierten Hypothese der Plattentektonik haben viele Forscher Anstrengungen unternommen die Entstehungsgeschichte und den geologischen Aufbau von Gebirgen nachzuvollziehen. Oberflächennahe Abläufe sind ansatzweise verstanden, während Prozesse im Erdinneren weit weniger bekannt sind. Informationen hierüber können jedoch aus den Gesteinen, ihren Mineralen und wiederum deren chemischen Komponenten gewonnen werden, da diese die Entstehung und Entwicklung der Gebirgsbildung “miterlebt”, und wichtige Informationen gespeichert haben. In dieser Arbeit wurden dazu exemplarisch (Ultra-) Hochdruckgesteine ((U-)HP), sogenannte Eklogite, und deren Umgebungsgesteine aus dem nordwestlichen Himalaja, insbesondere aus dem Kaghan Tal in Pakistan untersucht um den Exhumationsprozess von tief subduzierten Krustengesteinen im allgemeinen, und im Hinblick auf mögliche klimabedingte Einflüsse, besser zu verstehen. Die Bildung des Himalajas ist auf die Versenkung, eines südlich der eurasischen Platte angesiedelten Ozeans, der Tethys, und die nachfolgende Kollision Indiens mit dem Eurasischen Kontinent vor und seit etwa 50-55 Millionen Jahre zurück zu führen. Dabei wurden kalter, dichter Ozeanboden und leichtere Krustensegmente rasch in große Tiefen subduziert. Heute sind diese Hochdruck- und ultra Hochdruckgesteine in einigen Bereichen des Himalaja zwischen schwach metamorph überprägten (600-640°C/ca. 5 kbar) Gesteinen und alten Sedimenten der Tethys aufgeschlossen. Anhand von petrographischen, mineral-chemischen, petrologischen und isotopen-geochemischen Untersuchungen dieser (Ultra) Hochdruckgesteine konnte ich zeigen, dass 1) die Gesteine in über 100 km Tiefe also bis in den Erdmantel vordrangen, 2) sie bei ihrem Aufstieg in Krustenbereiche von 40-35 km zuerst von 790-640°C auf 630-580°C abgekühlten um danach wieder auf 720-650°C aufgeheizt zu werden, sie 3) innerhalb von 700.000 Jahren um mindestens 60 km Richtung Erdoberfläche exhumiert wurden und somit 4) Geschwindigkeiten von 9-14 cm pro Jahr erreichten, die der normaler Plattengeschwindigkeiten (>10 cm/a) entspricht, wobei sich 5) dieser Prozess ab 40-35 km auf 0.1-0.2 cm/a stark verlangsamte und auch 6) ab einer Tiefe von 6 km bis zur Erdoberfläche keine, z. B. niederschlagsbedingt, erhöhte Abkühlungsrate zu erkennen ist. Eine schnelle initiale Exhumierung erfolgte durch den Dichteunterschied von leichtem, subduzierten Krustengestein zum dichteren Mantel. Dieser Prozess kam an der Krusten-Mantel-Grenze nahezu zum erliegen, einhergehend mit einer sekundären Aufheizung des Gesteins und wurde, jedoch weit weniger schnell, durch die Kollision der beiden Kontinente Eurasien und Indien und dadurch bedingte Überschiebungen, Faltungen und gravitative Abschiebungen fortgesetzt, die Gesteine zur Oberfläche transportiert und dort freigelegt. Eine erosions- und damit klimabedingte Beschleunigung oder gar gänzlich davon abhängige kontinuierliche Exhumation konnte in dieser Region des Himalajas nicht bestätigt werden. Vielmehr belegen die Daten eine mehrstufige Exhumation wie sie auch im Tso Morari Gebiet (NW Indien) angenommen wird, für weitere Ultrahochdruckareale wie, z. B. das Kokchetav Massif (Kasachstan), den Dabie Shan (China) oder den europäischen Varisziden (z. B. Böhmisches Massiv) jedoch noch geklärt werden muss, um generell gültige Mantel- und Krustenprozesse abzuleiten.