During World War II, the United States Army employed a new weapon on the battlefield in an attempt to defeat German armor tactics: the tank destroyer. Tank Destroyer Force was created to stem the tide of German armored attacks and form an opening for American tanks to make their own counter-attacks. Since the end of the war, tank destroyer battalions have been regarded as a failed experiment, despite the evidence that they effectively did their jobs. The negative feedback in the immediate post-war period lead to the dissolution of the Tank Destroyer Force. Many of the studies of tank destroyers focus on the doctrine they followed and the faults in it. However, most of the studies do not look at the successful application of tank destroyer doctrine in the field by tank destroyer battalions. This paper will examine operations of the 773rd Tank Destroyer Battalion and its application of tank destroyer doctrine during the Battle of Chambois from August 17-21, 1944, for which it won a Presidential Unit Citation.

The thesis deals with the analysis of a reinforced concrete digestate tank. The tank is built as a semi-underground construction. The roof is designed as a reinforced concrete dome, which is prestressed in a circular beam with prestressing cables - monostrands. The calculation of internal forces were performed by the software SCIA Engineer. The structure was assessed for the ultimate limit state and the ultimate serviceability state, in terms of watertightness for the width of cracks.

No description available.

Argos mjölktank på Wedholms AB behöver utveckla vattenlåda med bättre säkerhet för el-kretsar på styrsystem samt reducera processtid för diskning av mjölktank.

The energy consumption in the world continues to increase, which makes energy saving measures important. In Sweden, where buildings account for a large part of total energy use, heat exchangers in ventilation are important to reduce energy consumption. However, Sweden's winters are often cold over large parts of the country, causing frost in the heat exchanger and high and uneven heating power requirements for ventilation units. The heating system in the building is required to manage the biggest power demand that may arise. From the ventilation unit, the greatest heating power requirement is arise in the event of frost conditions, as the power requirement from the heating coil increases during defrosting. By installing an accumulator tank together with the ventilation unit, the power requirement can be evened out. Power requirement for three different scenarios where the storage tank is used has been calculated. By using thermodynamic equations and measurements from Swegon counter flow heat exchanger results were accomplished. Optimal defrosting cycle times were evaluated by theory and equations. Other defrosting methods have been calculated to be compared to the solution with the accumulator tank. In a case with 600 litres per seconds supply and exhaust air flow, outdoor temperature at -10 ° C, the power requirement to the unit could be reduced by 67 % using an accumulator tank. An accumulator tank with a volume of 73 litres was required. By using an accumulator tank with the ventilation unit, investment costs could decrease by approximately 18 000 SEK when district heating is used as energy source. However, the solution with the storage tank will not be able to reduce district heating costs more than reduced flow cost for the district heating. If a heat pump I used approximately 95 000 SEK in investment cost could be saved when using an accumulator tank. Electricity cost could also be reduced but not much. Compared to other defrosting methods, the solution with accumulator tank will require the lowest power requirement for the ventilation unit, heat recover  most energy in the heat exchanger and at the same time create an even heat power requirement at frost conditions. / Energianvändningen i världen fortsätter öka vilket gör energisparåtgärder viktiga. I Sverige där byggnader står för en stor del av den totala energianvändningen är värmeväxlare inom ventilation viktiga för att minska energiförbrukningen. Dock är Sveriges vintrar ofta kalla över stora delar av landet vilket orsakar frostproblem i värmeväxlaren och högt och ojämnt värmeeffektbehov till ventilationsaggregat. Byggnadens värmesystem måste dimensioneras efter det största effektbehov som kan uppstå. Från ventilationsaggregatet sker det största värmeeffektbehovet vid frostförhållanden eftersom effektbehovet från värmebatteriet ökar vid avfrostning. Genom att installera en ackumulatortank tillsammans med ventilationsaggregatet skulle effektbehovet kunna jämnas ut. Effektbehov för tre olika scenarion där ackumulatortank används har beräknats. Det skedde genom användande av termodynamiska ekvationer och mätningar från Swegons motströmsvärmeväxlare. Tiden för hur lång avfrostningscykel som är optimal har utvärderas genom teori och ekvationer. Andra avfrostnings metoder har beräknats för att kunna jämföras med lösningen med ackumulatortank. I ett fall med till-och frånluftflöde på 600 l/s och dimensionerande utomhustemperatur på -10 °C kunde effektbehovet fram till aggregatet minskas med 67% genom att använda en ackumulatortank. En ackumulatortank med volymen 73 liter krävdes. Genom att använda en ackumulatortank tillsammans med ventilationsaggregatet kunde investeringskostnaden kunna minskamed cirka 18000 kr när fjärrvärme används som energikälla. Lösningen med ackumulatortank kommer dock inte kunna minska fjärrvärmekostnaden mer än att minska eventuell flödeskostnad för fjärrvärmen. Vid användande av bergvärmepump skulle cirka 95000 kr i investeringskostnad kunna sparas vid användande av ackumulatortank. Eleffektkostnaden kunde även minskas men relativt lite. Jämfört med andra avfrostningsmetoder kommer en lösning med ackumulatortank kräva lägst effektbehov till ventilationsaggregatet, återvinna mest energi i värmeväxlaren och samtidigt skapa ett jämt värmeeffektbehov under frostförhållanden.

Gegenstand der vorliegenden Dissertationsschrift ist das zumeist als Revolution of Military Affairs wahrgenommene Auftreten der ersten Panzer. Diese „Tanks“ der Jahre 1916-1918 mit den ihnen innewohnenden Möglichkeiten, das blutige Patt des Stellungskrieges an der Westfront aufzuheben, beeinflußten der Legende nach das Kriegsende 1918 erheblich. Die Alliierten erkannten das Potential der neuen Waffe, ließen sich von frühen Rückschlägen nicht entmutigen und besaßen gegen Ende des Krieges eine gepanzerte Speerspitze ihrer nun modern auf Feuer und Bewegung ausgelegten Offensiven, denen man deutscherseits angeblich nichts entgegenzusetzen hatte. Die deutsche Führung, anscheinend geprägt durch technikfeindliche und geradezu blauäugig agierende Köpfe, verpaßte bis zuletzt ignorant jede Chance, ihrerseits auf diese die Landkriegführung bis heute prägende Waffe zu setzen und selbst Tanks in Massen zu produzieren. Im Sommer 1918 kollabierten die deutschen Linien, als britische, französische und amerikanische Tankgeschwader unaufhaltsam auf sie und ihre technisch und taktisch plötzlich hoffnungslos unterlegenen Verteidiger einstürmten. Inwieweit diese plausibel erscheinende Darstellung den Realitäten in höchsten Führungskreisen beider Seiten und auf den Gefechtsfeldern entsprach, ist eine grundsätzliche Frage innerhalb der vorliegenden Dissertation. Anhand der operationsgeschichtlichen Untersuchung der namhaftesten Tankeinsätze zwischen dem ersten Auftreten der neuen Waffe im September 1916 und ihrem Siegeslauf im Sommer 1918 wird geklärt, welcher Anteil am alliierten Sieg den frühen Panzern zuzubilligen ist und inwiefern sich die deutsche Führung tatsächlich eines letztlich katastrophalen „Versagens“ schuldig machte. / The central theme of this thesis is the appearance on the battlefield of the first armoured vehicles, an event generally held to have been a revolution in military affairs. The exploits of these so-called ‘tanks’ of 1916 -1918, which had the inherent capability of breaking the bloody deadlock of trench warfare, contributed greatly during the interwar period to the promotion of a myth, which went roughly as follows: The Allies had recognised the potential of this new weapon; did not allow themselves to be deflected by early setbacks and so, towards the end of the war, their modern offensives, founded on the joint principles of fire and manoeuvre, possessed an armoured spearhead, against which the Germans had no answer. The German High Command, seemingly technophobic and blundering, ignored right to the bitter end, the chance to throw their weight behind the development and mass production of weapons, which to this day play a key role in land warfare. In the summer of 1918 the German lines simply folded in the face of British, French and American tank squadrons which rolled forward unstoppably to assault a defence which was suddenly and hopelessly tactically and technically inferior. The fundamental question of this thesis is to what extent this apparently plausible representation of the facts actually corresponds to the reality, both in the High Commands of both sides and on the battlefield. On the basis of historical-operational analysis of the most notable tank actions between the first appearance of the new weapon in September 1916 and its advance to victory during the summer of 1918, the thesis explores how much credit for the Allied victory is due to these early armoured vehicles and to what extent the German High Command itself was actually responsible for this final, catastrophic failure.

Esta dissertação de mestrado tem como objetivo a validação do modelo numérico de manobras para navios utilizado pelo simulador chamado SMH - Simulador Marítimo Hidroviário, que foi desenvolvido no laboratório Tanque de Provas Numérico. Para tanto foram realizados ensaios experimentais de manobras com um modelo em escala reduzida da embarcação Alpha Crucis com o objetivo de criar dados de manobra que serviram como referência para validação do modelo numérico. Foram selecionados diversos tipos de manobras com o propósito de criar uma caracterização da manobrabilidade da embarcação em baixas velocidades e regime transitório, permitindo a medição de diversas características, que permitem quantificar as capacidades de manobra da embarcação. Através de experimentos numéricos foram, então, realizadas as mesmas manobras executadas pelo modelo físico em escala reduzida, de forma a reproduzir as mesmas condições iniciais e os mesmos comandos, procurando reproduzir as manobras para validação do modelo implementado no SMH. Os resultados obtidos apresentam a aderência das características de manobras do modelo implementado no SMH, através da comparação das características de manobra obtidas pelo modelo físico em escala reduzida e das obtidas pelo modelo numérico. A dissertação apresenta ainda um estudo de sensibilidade que mostra o efeito dos principais fatores utilizados no laboratório Tanque de Provas Numérico para a calibração dos modelos de embarcações, mostrando que para as manobras consideradas neste trabalho alguns dos efeitos possuem pouca influência nos resultados. Por fim o trabalho conclui que o modelo matemático utilizado pelo SMH representa a capacidade de manobra da embarcação de forma consistente para diversos tipos de manobra, e com um grau de aderência satisfatório. / This research aims to present a validation for the ship maneuvering simulator named SMH, anachronym in Portuguese for Maritime and Waterway Simulator, developed on Tanque de Provas Numérico laboratory. For this propose small scale tests were performed with a model of Alpha Crucis ship aiming to create maneuver data that was used as reference for the numerical model validation. Several types of maneuver where selected to create a characterization of the maneuverability of the ship at low speeds and transient regime, and the parameters that quantify the maneuverability were measured. Then were performed numerical experiments recreating the same maneuver executed with the experimental model, with the same initial conditions and propulsion/rudder controls, trying to reproduce the maneuvers to validate the model implemented on the SMH. The results showed that the maneuvering characteristics predicted by the SMH simulator are similar to measured values in the experiment. The dissertation also presents a sensitivity study that shows the effect of the main parameters used in the laboratory Tanque de Provas Numérico for the vessel model calibration, This study showed that for some maneuvers, the tuning parameters have less influence on the results. Finally, the work concludes that the mathematical model used by the SMH represents the ability of the vessel to maneuver consistently for several types of maneuvers, and with a satisfactory degree of accuracy.

Liquid sloshing with unrestrained free surface in a moving container is associated with various engineering problems, such as tankers on highways, liquid oscillations in large storage tanks caused by earthquakes, sloshing of liquid cargo in ocean-going vessels, and the motion of liquid fuel in aircraft and spacecraft. The purpose of this study is to develop a three-dimensional (3D) numerical wave tank with or without internal structures to investigate the mechanism of liquid sloshing and the interaction between the fluid and internal structures. The developed 3D time-independent finite difference method is applied on solving liquid sloshing in tanks with or without the influence of baffles under the ground motion of six-degrees of freedom. The 3D Navier-Stokes equations were solved and transformed to a tank-fixed coordinate system, and the fully nonlinear kinematic and dynamic free surface boundary conditions for fluid sloshing in a rectangular tank with a square base were considered. The fluid is assumed incompressible in this study. The complicated interaction in the vicinity of the fluid-structure interface was solved by implementing one dimensional ghost cell approach and the stretching grid technique near the fluid-structure boundaries were used to catch the detailed evolution of local flow field. A PC-cluster was established by linking several single computers to reduce the computational times due to the implementation of the 3D numerical model. The Message Passing Interface (MPI) parallel language and MPICH2 software were utilized to code the computer codes and to carry out the circumstance of parallel computation, respectively. The developed numerical scheme was verified by rigorous benchmark tests. Not only the reported analytical, numerical and experimental studies were compared with the present numerical results, the experimental investigation was also involved in the present work to further validate the accuracy of the numerical scheme. All the benchmark tests of this study showed excellent accuracy of the developed numerical scheme. For a tank without internal structures, the coupled motions of surge and sway are simulated with various excitation angles, excitation frequencies and water depths. The characteristics of sloshing waves are dissected in terms of the classification of sloshing wave types, sloshing amplitude, beating phenomenon, sloshing-induced forces and energy transfer of sloshing waves. Six types of sloshing waves, named single-directional, diagonal, square-like, swirling-like, swirling and irregular waves, were found and classified in the present study and the occurrence of these waves are tightly in connection with the excitation frequency of the tank. The effect of excitation angle on the characteristics of sloshing waves is explored and discussed, especially for swirling waves. The spectral analyses of sloshing displacement of various sloshing waves are examined and a clear evidence of the correlation between sloshing wave patterns and resonant modes of sloshing waves are demonstrated. The mechanism of switching direction of swirling waves is discussed by investigating the situation of circulatory flow, the instantaneous free surface, the gravitational effect and the instantaneous direction of external forcing. The coupling effects of heave, surge and sway motions were also included in this study and the result showed an unstable influence of heave motion on the kinematic and dynamic characteristics of sloshing waves when the vertical excitation frequency of the tank is twice as large as the fundamental natural frequency. Except irregular waves, the other types of sloshing waves are converted into swirling waves due to the effect of heave motion. The study related to tuned liquid damper (TLD) in 2D and 3D tanks were considered. A comprehensive investigation for a 2D tank with vertically tank bottom-mounted baffles (baffled tank) are demonstrated and discussed with respect to the influence of baffle height on the natural mode of the tank, the evolution of vortices and vortex shedding phenomenon, the relationship between the vortex shedding frequency and the excitation frequency of the tank, the vortex size generated in the vicinity of the baffle tip, the interaction of vortices inside the tank. The baffle height shows a significant influence on the shift of the first natural frequency of the baffled tank and the liquid depth also plays an important part in determining this influence. In other words, the shift of the first natural mode due to various baffle height is varied with water depths. The design of two baffles separated by 0.2 times the tank breadth is an efficient tool to not only reduce the sloshing amplitude but switch the first natural frequency of the tank. The sloshing displacement is affected distinctly by different numbers of baffles mounted vertically on the tank bottom. The more baffles mounted onto the tank bottom, the smaller the sloshing displacement is presented in both the transient and steady-state periods. The processes of the evolution of vortices near the baffle tip are categorized into four phases: the formation of separated shear layer and generation of vortices, the formation of a vertical jet and shedding of vortices, the interaction between shedding vortices and sloshing flow (the generation of snaky flow) and the interaction between snaky flow and sloshing waves. Vortex shedding phenomenon due to stronger vertical jets occurs when the excitation frequency is close to the first natural mode of the baffled tank. The size of the vortex generated near the baffle tip is discussed and the vortex size is closely correlated with the baffle height. Two types of 3D tuned liquid dampers, a vertically tank bottom-mounted baffle and a vertical plate, are discussed for a tank under coupled surge-sway motions. The wave types of diagonal and single-directional waves switch to the swirling type due to the influence of the baffle. The phenomenon of square-like waves or irregular waves coexisting with swirling waves is found in the baffled tank under diagonal excitation. The baffle and the vertical plate mounted parallel to the east (west) wall of the tank can effectively reduce the sloshing amplitude when the excitation angle is between 0 degree and 10 degree and the corresponding sloshing displacement in the sway (z) direction becomes more dominant with the increase of the excitation angle. The shift of the first natural mode of the baffled tank due to various baffle heights in the x direction is dominated in this design of baffled tank. The length of the plate can cause a significant influence on not only the variation of the natural frequencies but the type of the sloshing waves. The influence of the vertical plate on the irregular waves is insignificant and several peaks appear in the spectral analysis of the sloshing displacement for the irregular waves and the numbers of peaks are more than that of the baffled tank.

Lifting method through the use of hydraulic jacks, can adjust column elevation of the structure in order to eliminate the stress burden caused by differential settlement , as well as recover the structure¡¦s initial state and force to avoid the form reconstructing caused by different over-settlement, save construction cost and reduce environmental impact, and so the life cycle of the building be able to last. The study based on ¡§The computer control system of hydraulic jacks¡¨, ¡§The repair method of settlement of floating roof tank¡¨, and the other technologies, which developed by lifting method development department, set up by the case company, has matured day by day to seek permanent development strategy through the utilization of the innovative lifting method in structure on reclaimed land or tanks, shop buildings, and structures which have different settlement problems, and so on, enable to last the life cycle of the building. This study consists of the information collection of lifting technology development through the literature of innovative technology and management strategy and interview of the owner and the decision-making manager of the case company, that total sum of person-time is 21, with the theme of the technical development of lifting method, the extension of market, and the internationalization. Making industry S.W.O.T analysis can not only find out the lifting development business of the case company but also the strategic direction, core competitiveness, the development direction, the permanent strategy to maintain the annual growth of the rate of marginal balance. According to research, the case company need to become a international company in order to maintain the annual growth of 20¢H of the operational goal. Taking Taiwan as the technical development center, the case company uses the local manpower and constructional material of the group¡¦s subsidiaries in overseas footholds to lower the quote cost and enhance the competitiveness, so that the case company can move toward internationalization gradually. Besides, to be competitive in lifting industry, the case company must be customer oriented, which means to design the unique custom-made lifting method for the customer¡¦s demand. Contenting customer¡¦s demand with cost, industry safety and time is the most important strategy to retain long-term competitiveness advantage. In strategic growth oriented, to be the top lifting company all over the world after one decade, the case company has to enhance core competitiveness of lifting method, including project management, project control, structural design capacity, computer control hydraulic jacks system development capabilities, and technical capabilities lifting. Meanwhile, the case company has to develop continuously new technologies and methods, combine with the group¡¦s subsidiaries to establish overseas footholds to extend the overseas market, train staff to obtain the international certificate and learn the second language, and makes the product and service different from other companies.

Esta dissertação de mestrado tem como objetivo a validação do modelo numérico de manobras para navios utilizado pelo simulador chamado SMH - Simulador Marítimo Hidroviário, que foi desenvolvido no laboratório Tanque de Provas Numérico. Para tanto foram realizados ensaios experimentais de manobras com um modelo em escala reduzida da embarcação Alpha Crucis com o objetivo de criar dados de manobra que serviram como referência para validação do modelo numérico. Foram selecionados diversos tipos de manobras com o propósito de criar uma caracterização da manobrabilidade da embarcação em baixas velocidades e regime transitório, permitindo a medição de diversas características, que permitem quantificar as capacidades de manobra da embarcação. Através de experimentos numéricos foram, então, realizadas as mesmas manobras executadas pelo modelo físico em escala reduzida, de forma a reproduzir as mesmas condições iniciais e os mesmos comandos, procurando reproduzir as manobras para validação do modelo implementado no SMH. Os resultados obtidos apresentam a aderência das características de manobras do modelo implementado no SMH, através da comparação das características de manobra obtidas pelo modelo físico em escala reduzida e das obtidas pelo modelo numérico. A dissertação apresenta ainda um estudo de sensibilidade que mostra o efeito dos principais fatores utilizados no laboratório Tanque de Provas Numérico para a calibração dos modelos de embarcações, mostrando que para as manobras consideradas neste trabalho alguns dos efeitos possuem pouca influência nos resultados. Por fim o trabalho conclui que o modelo matemático utilizado pelo SMH representa a capacidade de manobra da embarcação de forma consistente para diversos tipos de manobra, e com um grau de aderência satisfatório. / This research aims to present a validation for the ship maneuvering simulator named SMH, anachronym in Portuguese for Maritime and Waterway Simulator, developed on Tanque de Provas Numérico laboratory. For this propose small scale tests were performed with a model of Alpha Crucis ship aiming to create maneuver data that was used as reference for the numerical model validation. Several types of maneuver where selected to create a characterization of the maneuverability of the ship at low speeds and transient regime, and the parameters that quantify the maneuverability were measured. Then were performed numerical experiments recreating the same maneuver executed with the experimental model, with the same initial conditions and propulsion/rudder controls, trying to reproduce the maneuvers to validate the model implemented on the SMH. The results showed that the maneuvering characteristics predicted by the SMH simulator are similar to measured values in the experiment. The dissertation also presents a sensitivity study that shows the effect of the main parameters used in the laboratory Tanque de Provas Numérico for the vessel model calibration, This study showed that for some maneuvers, the tuning parameters have less influence on the results. Finally, the work concludes that the mathematical model used by the SMH represents the ability of the vessel to maneuver consistently for several types of maneuvers, and with a satisfactory degree of accuracy.