No / Iron Age studies in northern Britain have been dominated by one monument form, the broch. This focus on these monumental towers of the Atlantic Scotland, perhaps at the expense of other archaeological evidence, has brought about a strong division in the archaeological community. MacKie and Armit have both recently summarized the development of broch studies detailing the opposing arguments for the date of construction. In recent years archaeological evidence for these monuments has indicated an indigenous development rather than being associated with the movement of Iron Age peoples. This paper presents new chronological data for the construction of a Shetland broch and examines the archaeological repercussions for the 'early' chronology provided by these dates. Excavations at Old Scatness in the South Mainland of Shetland have revealed new evidence for a broch and defended Iron Age Village.

Cette thèse a pour objectif d’explorer la relation entre les caractéristiques socio-culturelles et les politiques de reconstruction post-séisme dans les zones rurales de Azad Jammu et du Cachemire, au Pakistan. L’objet principal est d’examiner les pratiques architecturales traditionnelles : dhajji-dewari et la composition sociale de la communanuté pendant et après la reconstruction. Différents processus sont analysés: comment les aspects socio-culturels des sociétés rurales sont affectés par les politiques de reconstruction? Comment les politiques sont touchées par les aspects socio-culturels des commmunautés? Comment la combinaison des deux influence le processus final?Ce travail de thèse part du constat que 80% des 600 000 bâtiments endommagés ou détruits lors du séisme du 8 octobre 2005 au Cachemire, étaient des maisons rurales provisoires (Katcha). Il s’agit d’examiner jusqu’où le Programme de Reconstruction de Logement Rural (RHRP) qui a concerné quelque 100 000 maisons dhajji, a réduit ou augmenté la vulnérabilité de la zone pour l'avenir. Ce programme a été initié à partir de l’expérience de précédents programmes de reconstruction post-tremblements de terre, qui ont été d’une grande utilité pour les experts. Il restait à analyser les erreurs commises ou répétées par les différents acteurs pendant les phases d’élaboration, de validation, de mise en œuvre, et de suivi des politiques de reconstruction. Les principaux résultats de la thèse couvrent trois thèmes relatifs aux différentes étapes de la reconstruction : la durabilité de la reconstruction ; la réduction de la vulnérabilité de la reconstruction ; les résultats qui n’entrent pas dans les catégories “durabilité” et “vulnérabilité” selon les experts du Cachemire rural. La satisfaction des communautés est l’indicateur principal permettant d’évaluer les principaux résultats. L'étude conclut que la non-prise en compte des aspects socioculturels des communautés pendant la reconstruction peut augmenter la vulnérabilité du scénario de post-reconstruction. Le suivi du programme de reconstruction consiste à évaluer les tendances liées aux maisons en construction. En présentant par des illustrations les détails architecturaux de ces maisons reconstruites, l’écart avec les recommandations est évalué. Après que quelques années, les populations oublient les impacts du séisme et leurs besoins immédiats dictent leurs priorités de décision. Il est suggéré qu'à la fin du programme de reconstruction, la présence des autorités dans la zone reconstruite permette d’assister les populations dans leurs besoins actuels et futurs, et de contrôler le développement des constructions non conformes. / This thesis is aimed at exploring the relation of socio-cultural characteristics and policies with post-quake reconstruction of rural areas of Azad Jammu & Kashmir, Pakistan. The primary concern of the study is limited to examine the traditional architectural practice ; dhajji-dewari and social composition of the community during and after reconstruction. It is analyzed that how the socio-cultural aspects of rural communities are affected by the policies, how policies are affected by the socio-cultural aspects of the community and how both of these can influence the final product. The thesis was rooted in the fact that 80% of the 600,000 damaged/destroyed buildings during 8th October, 2005 Kashmir earthquake were rural temporary (Katcha) houses. It was hence to be investigated that how far the Rural Housing Reconstruction Program (RHRP) has reduced (or increased) the vulnerability of the area for future. The impact of any policy launched during this program was not limited to few housing units rather more than 0.1 million dhajji houses could be affected through this. The rural Kashmir reconstruction was commenced with the in-hand knowledge of several previous post-quake reconstruction programs and was appreciated widely by experts. It was yet to be explored that which mistakes were committed/repeated by the stakeholders during policy making, delivery, implementation and post implementation phases. Covering the phases of policy making, delivery and implementation, the major findings of the thesis are categorized into three sections ; the sustainability generating aspects of reconstruction, vulnerability enhancing dimensions of reconstruction, and, those outcomes of reconstruction which are not yet categorized under ”sustainability” or ”vulnerability” by the experts focusing particularly rural Kashmir. Community satisfaction is given primary focus to rate different outcomes.The study concludes that ignoring socio-cultural aspects of the community during reconstruction may lead to vulnerability in post-reconstruction scenario. Considering the post implementation phase, the current trends are observed by examining under-construction houses. By pictorially presenting the architectural details of these houses it is examined that deviations from guidelines are in practice. People start forgetting the disaster impacts after few years and their immediate needs drive their decision priorities. It is suggested that after reconstruction program ends up, some authorities must be present in the reconstructed area to guide people for their current requirements and future needs and also to control the spread of non compliant construction.

Neste trabalho foi realizada a modelagem fenomenológica do desempenho de uma torre de resfriamento de água e de um sistema de duas torres de resfriamento em série, com temperatura de água de entrada de até 65 ºC. Verificou-se a validade do modelo através de comparação dos resultados previstos com os obtidos em ensaios em uma unidade piloto. Em seguida, através de simulação matemática, a partir do modelo desenvolvido, foi feito o estudo de diversos casos de aplicação. Estudou-se a influência das principais variáveis de operação (vazão de ar, vazão de água e temperatura de bulbo úmido) no desempenho de torres de resfriamento acopladas (em série e em paralelo) e no custo operacional. Verifica-se que a variável de maior influência é a vazão de água que circula pela torre. / This is a study about the phenomenological modeling of the performance of a water cooling tower and a system of two cooling towers in series, with water temperature input up to 65°C. The validity of model was verified by comparing the expected results with those obtained in tests on a pilot plant. After this, through a mathematical simulation, based on the model developed, several cases of application were analyzed. It was studied the influence of main operating variables (air flow, water flow and wet bulb temperature) on the performance of couples cooling towers (in series and parallel) and on operational cost. It was verified the most influential variable is the water flow rate through the tower.

Neste trabalho foi realizada a modelagem fenomenológica do desempenho de uma torre de resfriamento de água e de um sistema de duas torres de resfriamento em série, com temperatura de água de entrada de até 65 ºC. Verificou-se a validade do modelo através de comparação dos resultados previstos com os obtidos em ensaios em uma unidade piloto. Em seguida, através de simulação matemática, a partir do modelo desenvolvido, foi feito o estudo de diversos casos de aplicação. Estudou-se a influência das principais variáveis de operação (vazão de ar, vazão de água e temperatura de bulbo úmido) no desempenho de torres de resfriamento acopladas (em série e em paralelo) e no custo operacional. Verifica-se que a variável de maior influência é a vazão de água que circula pela torre. / This is a study about the phenomenological modeling of the performance of a water cooling tower and a system of two cooling towers in series, with water temperature input up to 65°C. The validity of model was verified by comparing the expected results with those obtained in tests on a pilot plant. After this, through a mathematical simulation, based on the model developed, several cases of application were analyzed. It was studied the influence of main operating variables (air flow, water flow and wet bulb temperature) on the performance of couples cooling towers (in series and parallel) and on operational cost. It was verified the most influential variable is the water flow rate through the tower.

Industrial and mining sectors are amongst the largest single energy consumers in South Africa, making them a primary focus for implementing energy saving initiatives. Refrigeration systems on mines are responsible for consuming up to25 % of the electrical energy consumption on a typical South African deep level mine. Ample opportunities to reduce the energy consumption of these systems exists, as many of the current systems rely on old technology and function under partial or inadequate control management. In compiling this thesis, various energy saving strategies on deep level mines were investigated. In specific, the effects of controlling and improving the cooling auxiliaries. Scenarios were investigated and simulated, where after an optimum solution was implemented. Implementations, such as the ones covered in this dissertation, form part of the IDM (Integrated Demand Management) energy efficiency incentive introduced by Eskom, where funding is made available based on actual power saving; ensuring that the projects will be financially viable to the clients. Reduced electrical energy consumption realised from the abovementioned projects were measured, captured and compared to the consumption before project implementation to determine the achieved savings. Savings of up to 30 % of the plant installed capacity were realised, providing average savings of up to 2.3 MW per day. / Thesis (MIng (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2013

Industrial and mining sectors are amongst the largest single energy consumers in South Africa, making them a primary focus for implementing energy saving initiatives. Refrigeration systems on mines are responsible for consuming up to25 % of the electrical energy consumption on a typical South African deep level mine. Ample opportunities to reduce the energy consumption of these systems exists, as many of the current systems rely on old technology and function under partial or inadequate control management. In compiling this thesis, various energy saving strategies on deep level mines were investigated. In specific, the effects of controlling and improving the cooling auxiliaries. Scenarios were investigated and simulated, where after an optimum solution was implemented. Implementations, such as the ones covered in this dissertation, form part of the IDM (Integrated Demand Management) energy efficiency incentive introduced by Eskom, where funding is made available based on actual power saving; ensuring that the projects will be financially viable to the clients. Reduced electrical energy consumption realised from the abovementioned projects were measured, captured and compared to the consumption before project implementation to determine the achieved savings. Savings of up to 30 % of the plant installed capacity were realised, providing average savings of up to 2.3 MW per day. / Thesis (MIng (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2013

Cette étude porte sur les systèmes défensifs d'une quarantaine de villes petites et moyennes, édifiés en Alsace centrale entre les XIIIe et XVe siècles, jusqu'à leur déclassement ou démantèlement définitif au XIXe siècle. Les ressources sollicitées sont de natures diverses : prospections des vestiges conservés, sondages archéologiques, documentation iconographique (plans, gravures, photographies anciennes), archives médiévales et modernes. Parmi ces dernières, une grande enquête sur l’état de conservation des enceintes des petites villes, bourgs et villages d’Alsace, initiée par le directeur des fortifications d’Alsace en 1779, livre un tableau exhaustif des systèmes fortifiés avant leur abandon. Les questions abordées portent sur les matériaux de construction, les diverses composantes de la défense (portes, murs, fossés, remparts...), les données topographiques et la chronologie des aménagements. Les enseignements majeurs, dans un domaine où seules les enceintes des grandes villes ont jusqu'à présent attiré l'attention, sont la diversité des réponses apportées au besoin de défense mais également des chronologies et types de structures qui n'ont rien à envier à ces grandes villes. Tout au moins jusqu'au XVIe siècle ; car sauf exception, ces villes petites et moyennes n'ont en effet pas pu prendre le virage du bastionnement des fortifications. Elles ont en revanche assez bien entretenu les structures héritées du Moyen Âge pour encore pouvoir être considérées comme des points d’appui dans la défense de la région par l'administration royale peu avant la Révolution. / This study deals with the defensive systems of three dozen small and middle-sized towns of central Alsace, from their building between the 13th and 15th Centuries, to their definitive dismantling during the 19th Century. Various resources were exploited : examination of existing remains, archaeological surveys, visual sources (maps, prints, old photographs), Middle Age and Modern period archives. The latter source included a major condition report on Alsace’s small cities, towns and villages, initiated by the province’s head of fortifications in 1779, which offers a complete overview of fortification systems before they were abandoned.The study addresses the questions of the construction materials used, the variety of defensive elements (doors, walls, moats, ramparts, etc.), topographical data and a chronology of their construction.The major teachings, in a field so far focused on large cities’ walls, are the broad range of solutions to the protective needs and the diversity of their chronology and layout models that are just as interesting as those of larger cities. This is noted until the 16th Century, when, with few exceptions, these small and middle-sized towns were not able toupgrade their defense to the level of bulwarks. Well maintained though, they were still seen as a major defensive support for the region by the royal administration, soon before the French revolution.

The transmission line (TL) tower is an important component in electrical network system. These towers consist of members (angle sections) and connections (bolted connections) plus foundation, which act together to resist externally applied loads. The latticed towers are used to support conductors in transmission network for transmission and distribution of electricity. These towers are constructed in large numbers all over the world. The connections in electric TL classical latticed towers are peculiar compared to other types of bolted connections in buildings and bridges because (i) the angle members are connected directly or through gusset plates with bolts, (ii) the eccentric application of load due to the non-coincidence of centroid axes of angle members near the connection and (iii) members are designed as beam column element to sustain tensile or compressive forces. Bearing type bolts are used in TL towers in preference to friction type bolts, because they (i) connect thin walled angle members, (ii) are easy to use for erection at all heights, (iii) can be galvanized, (iv)erosion of galvanizing can be remedied and (v) do not require skilled personnel for installation. However, these connections are subjected to reversal of stresses due to wind load. Damage in the bolted connections generally occur due to loosening of bolts due to stress reversals (Feenstra et al. (2005) [23). The damage induced after extreme wind and earthquake may lead to collapse of the whole tower. The failure of a TL tower results in power shut down, which has huge impact on national economy. Hence, the structural safety and reliable performance of these towers are extremely important. The design of TL tower is based on minimum weight philosophy. The TL towers are highly repetitive and therefore, their designs need to be commercially competitive. The TL tower design has the following deficiencies such as misappropriate design assumptions, deficit detailing, defects in material, errors in fabrication, force fitting of members during erection, variation in grade of bolts, improper gusset plate detailing, notch cutting of member, vocalization of bolt holes, etc. Hence, to check the design and detailing aspects of members along with bolted connections and to study the behavior of tower under complex loading conditions, the prototype testing of tower is made mandatory requirement in many countries throughout the world. The structural behavior of TL tower is determined from its deflection response. Thus, the full scale testing of the towers is the only way that one can counteract the un conservatism due to structural analysis. The premature failure of TL towers occurs during prototype testing due to deficiencies in joint detailing, uncertainties in framing eccentricity, force fitting of members, unequal force distribution in bolts and gusset plate connections, etc. To have better structural response of TL tower to be tested, there is need to develop reliable model for bolted connections in TL towers. The bolted connection model plays an important role in determining the deflection response and predicting the premature member buckling failure of TL towers. The issues related to prototype testing of full scale TL towers such as fabrication errors, force fitting and notch cutting of members, application of loads, joint and crossarm detailing are discussed. The need to develop bolt slip model to simulate the actual behaviour of bolted connection in TL towers is also discussed. The bolted connections in TL towers play an important role in determining its structural behavior. The angle members used in TL towers are subjected to bi-axial bending in addition to axial load. The slip will occur in the bolted connections, due to the provision 1.5 mm bolt hole clearance. In the conventional Finite Element Analysis (FEA), the bolted connections are modeled as pin joint assuming the axial load transfer. The deflection predicted from pin joint analysis in TL towers generally does not match with experimental results. The analytical and experimental deflection value varies in the range of 30 to 50%. Hence, there is need to develop model to account bolt slip for accurate deflection and dynamic characteristic prediction of TL towers. Experimental and analytical investigations have been carried out to develop and validate bolt slip model for bolted connections in TL towers. All six degrees of freedom (both translational and rotational) have been considered to simulate the exact behaviour of bolted connections in TL towers. The model is developed based on experimental results of Ungkurapinan’s bolt slip model for axial stiffness. The rotational stiffness is formulated based on the component level experiment conducted on lap joint made of steel angle with single and double bolt subjected to tensile loading. The axial and rotational stiffness for different stages of bolt tightening is also formulated based on component level experimental investigation on lap joint. The proposed model is validated by comparing with experimental results at sub-structural level on full scale king post truss subjected to tensile loading. Further the bolt slip model is validated for different bolt tightening and failure prediction of TL tower sub panel subjected to tensile loading. Finally the proposed model is also validated for full scale TL tower for deflection prediction. NE NASTRAN, a nonlinear finite element analysis (FEA) software is used for analytical simulation and the load-deflection predictions, which are compared with the corresponding experimental results. The experimental and analytical results are in good agreement with each other. The steel pole structures are replacing the conventional lattice towers, because they have smaller plan dimension and occupy less space, when compared to lattice towers. The steel pole structures are dynamically sensitive structures and the determination of their natural frequency is extremely important. For the calculation of wind load through gust factor method, the preliminary estimation of natural frequency is required. Hence, the primary step involved in dynamic analysis is the evaluation of its natural frequency. Hence, a simplified model is proposed based on model order reduction technique for the evaluation of natural frequency of TL towers and steel pole structures. For the development of base line model to detect damage in TL towers, the natural frequency has to be updated. A semi empirical approach is proposed based on the deflection by using the proposed bolt slip model. The proposed approach of updating natural frequency is validated for different cases of member damage in TL tower sub panel, such as removal of tension, compression and hip bracing members. The transmission pole structures accumulate damage during their service life. Damage in these structures will cause a change in stiffness of the system and the physical properties of these structures, such as modal frequencies and mode shapes. Hence in the present study, the damage localization study based on modified modal strain energy approach is carried out for steel pole structures and the location of damage is identified correctly. To prevent premature failure of towers during its service life testing and failure analysis of TL towers is a mandatory requirement. In the present study, forensic failure investigation of a full scale TL tower due to deficient design of a redundant member is emphasized and the remedial measures are explained in detail. The stub failure of TL tower due to reduction in cross sectional area due to unfilled bolt hole is also discussed. To investigate the effect of unfilled bolt holes on the compression capacity of leg member, detailed FEA is carried out and compared with experimental results. The reason for failure of 9 m roof top communication tower due to redundant member deficiency is also discussed. The importance of guyed tower accessories in the guy rope design of 7 m roof top guyed pole structure is also investigated. Finally, failure investigation of compression bracing member, which has failed during testing of TL tower sub panel has been investigated. The failure load is predicted by using the proposed bolt slip model in the analysis. Thus the overall research contributions emerging from this thesis are, i) development of bolt slip model accounting for rotational stiffness, ii) development of direct method of damage detection for steel pole structures based on modified modal strain energy approach, iii) development of simplified model for prediction of natural frequency of TL tower and steel pole structures, iv) development of model updating technique through natural frequency based on semi-empirical approach and v) prediction of failure load for TL tower panel using the proposed bolt slip model.

This diploma thesis deals with the problematics of fan cooling towers. The very first part of the text is research, focusing mainly on the theory of cooling and the function of fan cooling towers in general. The following chapter deals with the water resource management of the Dukovany nuclear power plant and the specification of its objects of forced draft cooling towers. The second part describes a computational model created to determine the cooling performance of these towers under the given input conditions. In the following chapters, the results from the computational model are compared with the available data from warranty measurements and with the provided characteristics. The final pages deal with the study of the influence of changes in input parameters on the cooling performance and the research of the behavior of the cooling towers under extreme weather conditions.

Cement hydration is the result of a series of simultaneous chemical reactions occurring during the production of concrete. An excessive amount of heat is generated, which consequently may give rise to thermal stresses and cause early age cracks in concrete that may affect its structural integrity, and load bearing capacity. Incorporating fly ash into the concrete mixture has shown to be an efficient method to reduce the temperatures developed during early age hydration, especially for massive concrete structures. Fly ash does additionally affect the concrete's development of compressive strength, tensile strength and Young's modulus. The MahanaKhon tower's mat foundation is divided into 14 layers, with fly ash incorporated in the concrete mix. A finite element model was developed of the mat foundation with COMSOL Multiphysics to simulate the developed temperatures and thermal stresses during curing. The simulations were carried out as parametric studies with different strain reference temperatures. The simulated temperatures were compared with existing temperature measurements that were conducted in three different elevations in each concrete layer. The result of the temperature analyses showed that the measured temperatures were generally larger than the simulated ones, which may have been the result of the numerical model's heat conductivity and convective heat transfer coeffcient not reflecting the actual case. Furthermore, the numerical model did not take into account the effects of solar radiation, which would most likely have increased the temperature of the concrete. The maximum simulated temperatures were mostly found in the center level of the concrete, followed by the lower level, and the lowest at the top. It was also observed that the maximum temperatures in some of the mat foundation layers could exceed 70 °C, which is generally considered high since the risk of delayed ettringite formation may arise. The large temperature is partially a result of not using cooling methods, such as cooling pipes, but also due to the high initial and ambient temperatures. The result of the thermal stress analyses showed that no tensile stresses arose when the strain reference temperature, Tref, was specified to 30 °C, corresponding to the mean ambient temperature. This is due to the concrete temperature not falling below Tref, and the concrete will therefore be in expansion and only be subject to compressive stresses. Increasing Tref to 50 °C, which was considered a reasonable estimation, resulted in developed tensile stresses in all mat foundation layers, where the majority of the mat foundation layers showed a risk of superficial surface cracks. The maximum tensile stresses were found at the final time of the simulations, which was expected, since the temperatures were at their lowest as a result of removing the curing insulation. Finally, setting Tref to 70 °C, corresponding to the maximum temperature during hardening, increased the induced tensile stresses considerably, due to the large temperature gradient between Tref and the concrete temperature. The maximum stresses were, as expected, located at the top level and caused by internal restraint. The second largest tensile stresses were found in the center level, also subject to internal restraint. The lowest tensile stresses were located in the lower level, subject to external restraint. / Cementhydratation är resultatet av en serie kemiska reaktioner som sker under tillverkningen av betong. Stora mängder värme genereras, vilket följaktligen kan ge upphov till termiska spänningar och orsaka tidig sprickbildning som påverkar betongens hållfasthet, och bärförmåga. Inkludering av flygaska i betongblandningen har visat sig vara en effektiv metod avsedd att minska temperaturerna som utvecklas under hydratationen i ung betong, särskilt i massiva betongkonstruktioner. Flygaska påverkar också betongens utveckling av tryckhållfasthet, draghållfasthet och elasticitetsmodul. MahanaKhon towers bottenplatta är uppdelad i 14 lager, där flygaska inkluderades i bottenplattans betong. En finit elementmodell av bottenplattan skapades i COMSOL Multiphysics, där de utvecklade temperaturerna och termiska spänningarna i den unga betongen simulerades under bottenplattans härdningsfas. Simuleringarna genomfördes som parameterstudier med olika referenstemperaturer. De simulerade temperaturerna jämfördes vidare med befintliga temperaturmätningar som utfördes i tre olika elevationer i varje gjutetapp. Resultaten av temperaturerna visade att de uppmätta temperaturerna var generellt högre än de simulerade, vilket bland annat kan bero på att betongens värmeledningsförmåga, samt konvektiva värmeöverföringskoefficient inte återspeglade det aktuella fallet. Den numeriska modellen tog inte heller hänsyn till effekten av solinstrålning, som sannolikt skulle ökat betongens temperatur. De maximala temperaturerna hittades mestadels i betongens mittnivå, följt av den lägre nivån och slutligen lägsta nivåerna vid toppen. Det observerades även att de maximala temperaturerna i bottenplattan kunde överstiga 70 °C, vilket generellt anses vara högt då risken för fördröjd ettringitbildning kan uppstå. De höga temperaturerna beror delvis på avsaknad av kylmetoder, såsom kylrör, men även på den höga initialtemperaturen och omgivningstemperaturen. Resultaten av spänningsanalysen påvisade att inga dragspänningar uppstod när referenstemperaturen Tref denierades till 30 °C, som motsvarar den genomsnittliga omgivningstemperaturen. Detta förklaras av att betongen kommer att vara i expansion och följaktligen endast utsättas för tryckspänningar. Efter att Tref ökats till 50 °C, vilken ansågs vara en rimlig estimering i denna studie, uppstod dragspänningar i alla lager i bottenplattan, där vissa utsattes för risk för ytsprickor. De maximala dragspänningarna uppstod vid simuleringarnas slut, vilket var förväntat då temperaturerna var som lägst vid den tidpunkten till följd av att isoleringen avlägsnades. Slutligen höjdes Tref till 70 °C, vilket motsvarar den maximala temperaturen i bottenplattan under härdning. De inducerade dragspänningarna ökade avsevärt på grund av den stora temperaturgradienten mellan Tref och betongtemperaturen. Samtliga lager utsattes i detta fall för risk för genomgående sprickor. De maximala dragspänningarna påträffades på toppnivån och orsakades av inre tvång. De näst största dragspänningarna fanns i mitten av plattan och var också resultatet av inre tvång. De lägsta dragspänningarna påträffades vid plattans lägre nivå, som utsattes för yttre tvång.