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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.
261

Digital pumps in speed-controlled systems – an energy study for a loader crane application

Kärnell, Samuel, Rankka, Amy, Dell`Amicio, Alessandro, Ericson, Liselott 25 June 2020 (has links)
Imagine a system with a pump driven by a speed-controlled electric motor. What and how much can be gained by using a pump with discretely variable displacement instead of a conventional fixed pump in such a system? This question is the focus in this paper, in which a simulation study based on a drive cycle for a loader crane is presented. The results indicate that the system efficiency from inverter input to pump output can increase by a few percentages. This might be considered small in relation to the increasing complexity that comes with discrete displacement. However, the results also show that a system with discrete displacement substantially reduces torque and cooling requirements on the electric motor. The required maximum torque can be reduced by 30 to 50 % and the motor can generate up to 40 % less heat since it can work in more efficient conditions. These potential benefits will be obtained with only a few discrete displacement settings available.
262

Galéria Lučenec - vybrané části stavebně technologického projektu / Galéria Lučenec - selected parts of the construction technology plan

Jakobei, Michal January 2022 (has links)
The main purpose of this thesis is to describe in detail the processes of selected parts of the construction technology project for the construction of the department store Galéria Lučenec, based on the project documentation provided by the principal engineer. It is a large-scale new building with a cast-in-place reinforced concrete load-bearing structure with steel elements located in the center of Lučenec. The diploma thesis consists of the main parts such as the technical report of the construction technology project, a detailed coordination situation of the construction site, and a detailed time and financial plan of individual buildings. Within the main building, a study of the main technological stages of construction, elaboration of the project site equipment together with the associated design documentation and the technical report, design of the main construction machines and mechanisms, time schedule of the main building processes, and an item budget are described. Within the technological regulation and the control plan, the diploma thesis is focused on the cast-in-place structures of the superstructure. In the final part of the project, there are chapters devoted to topics such as occupational health and safety on the construction site, evaluation of LEED 2009 certification, the procedure for securing the construction pit, and the assessment of the main vertical lifting mechanisms.
263

Příprava realizace bytové výškové budovy v Bratislavě / Preparation for the implementation of a high-rise apartment building in Bratislava

Krajčovič, Matúš January 2022 (has links)
The subject of this diploma thesis is processing of a construction technological project for the preparation of the realization of a high-rise residential building in Bratislava. The thesis is based on construction technology solution. The content of thesis is a technical report, coordination situation with broader transport relations, time and financial plan, study of realization of technological stages, solution of construction organization including drawing of construction site, design of main construction machines and mechanisms, technological regulation for upsite monolithic construction, control and testing plan, item budget, detail of relief elements of the ceiling structure, drawing of the formwork of the ceiling structural floor, specific research in the field of tower cranes.
264

Montovaná železobetonová hala s jeřábovou dráhou / Prefabricated reinforced concrete hall

Jakubcová, Hana January 2022 (has links)
The main work of the diploma thesis is a draft and a static judgement of chosen horizontal and vertical parts of prefab hall with a crane runway. The chosen parts are the girder, the column, the bracing, the foundation beam, and the foundation pad. The model for gathering of intern forces is made by the program SCIA Engineer 18.1 with the use of a bar 3D model of the whole project. The parts were judged on the ultimate limit state. The prestressed girder was judged on the ultimate limit state and the serviceability limit state.
265

Budova VZP ČR Jihlava - stavebně technologický projekt / Building VZP ČR Jihlava – construction and technological project

Kotrč, Ondřej January 2012 (has links)
The aim of the diploma thesis is a constructional and technological project of regional branch VZP in the town Jihlava. The project includes a building site outfit, technological rule for prefabricated skeletel constructions, budget, time schedule, kontrol and test plans, design of machine works, contract for work and safety report. As a part of the diploma thesis is also confrontation contact heta cladding system and heat cladding system with a ventilated air gap. The last supplement is safety report at demolitions.
266

Investigation of torsion modes in overhead traveling cranes: : Reviewing the ISO 22980 standard

Jens, Simon January 2023 (has links)
Overhead cranes and rail mountings in the wall are subjected to vibrations whenlifting equipment. The purpose of this thesis is to review if the minimum frequencyvalue for cranes, according to the ISO 22986:2007 standard is conservative whendesigning overhead traveling cranes. To succeed with the purpose of this thesis,the objective is to compare measured to simulated vibration data on an overheadtraveling cranes. MSC Nastran and MATLAB were used to compare the measureddata to the simulated model. Experimental vibration data on a crane at Volvo CEwas obtained by using the program Siemens Test Lab. The experimental vibrationdata were correlated to the finite element model, by using the modal assurance criteriabetween the mode shapes of the experimental and finite element models. Thefinite element model was used to conduct a study which resembles the operationmovements of the crane. The result of the load investigation where a trolley movesalong the girder on the overhead crane, showed that the ISO 22986:2007 standard isnot conservative in regards to the displacement due to movements during operationof the crane, since the standard does not consider 13% of the displacement whichis due to the torsional modes. When considering an extreme case where the entireload of the trolley was placed on one side of the girder 51% of the displacement wasin response to the torsional modes in this study. Thereby, the minimum frequencyallowed on the overhead cranes does not consider the torsional vibration’s contributionwhich have a significant impact on the displacement when the trolley movesover the girder. / Traverser och traversrälar som är monterade i väggen, utsätts för vibrationer när delyfter utrustning. Syftet med detta examensarbete är att granska om lägsta frekvensenför traverser, enligt ISO 22986:2007 standarden är konservativ när den användssom underlag för att designa traverskranar. För att kunna undersöka detta behöveruppmätta vibrationer från en fysisk travers jämföras med vibrationsdata från enFinita-elementmodell av en travers för att validera modellen. MSC Nastran ochMATLAB användes för att jämföra uppmätta data med den simulerade modellen.Vibrationsdata uppmättes på en travers på Volvo CE Braås. För denna mätninganvändes programvaran Siemens Test Lab. Den experimentella vibrationsdatanvaliderades emot finita-elementmodellen genom att jämföra "modal assurance criterion"för den experimentellamodellen och finita-elementmodellen. Den valideradefinita-elementmodellen användes för att utföra en studie av traverskranen där driftsrörelserav kranen simuleras. Resultatet av lastutredningen där en tralla rör siglängs balken på traversen, visade att ISO 22986:2007 standarden inte är konservativmed avseende på förskjutningen på grund av rörelser. I de studerade fallen tarstandarden inte hänsyn till 13% av förskjutningen som beror på vridsvängningarna.När extremfallet analyseras där hela lasten av trallan placerades på ena sidan avtraversbalken var 51% av förskjutningen på grund av vridningssvängningarna. Denlägsta tillåtna frekvensen på traverskranarna tar därmed inte hänsyn till torsionsvibrationernasbidrag som har en betydande inverkan på förskjutningen när vagnenrör sig över balken.
267

Efficient heuristics for large-scale vehicle routing problems

Graf, Benjamin 02 September 2021 (has links)
In this thesis we consider three challenging vehicle routing problems representing specific aspects of complex real-world problems: (i) the vehicle routing problem with unit demands, (ii) the preemptive stacker crane problem and (iii) a multi-period vehicle and technician routing problem. For the vehicle routing problem with units demands we continue research on the exponential multi-insertion neighborhood, investigate its properties and propose heuristic solution methods utilizing the neighborhood. For the preemptive stacker crane problem we study structural properties and provide bounds on the benefits of preemption and the benefits of so-called explicit drop nodes that are used exclusively to facilitate preemption. We propose construction heuristics that improve on the state-of-the-art in computational time and solution quality. The multi-period vehicle and technician routing problem is the subject of the VeRoLog Solver Challenge 2019. We develop a solution method that adapts to the limited computational budget and the given instance parameters. In summary, this thesis contributes to the structural analysis of the considered problems and proposes efficient heuristic solution methods that are effective even on large-scale instances and under tight restrictions of the computational budget. The methods combine global and local search approaches and take the available computational budget into account to realize an adaptive best-effort allocation of the resources.
268

Ersatz von Auflagerkonsolen für schwere Kranbahnträger im Bauwerksbestand

Dreiling, Alexander, Rieche, Marco, Kretzschmar, Peter 08 November 2023 (has links)
Mit Ende des 2. Weltkrieges waren weite Teile Deutschlands und der Industriegebiete zerstört. Nach einer Phase von Reparaturen und Erweiterungen wurden viele Betriebe auf dem Gebiet der Bundesrepublik und der DDR in den 1960er und 1970er Jahren neu errichtet oder umfassend modernisiert. Die in dieser Zeit entstandenen Industriebauten sind mittlerweile mehr als 50 Jahre in Betrieb und die rechnerisch ermittelten Lebensdauern sind oftmals überschritten. Neben einer verlängerten Nutzung der Anlagen wurden diese vielfach erweitert, neugestaltet und müssen oft höhere Produktionsbelastungen ertragen, als während der Errichtungsphase ermessen wurde. Demzufolge ergeben sich für die Erneuerung von alten Bestandsbauten und deren Kranbahnen hier im Besonderen völlig andere Randbedingungen als beim Neubau „auf der grünen Wiese“. Am Beispiel einer sehr komplexen Umbaumaßnahme zur Erneuerung einer Kranbahn im industriellen Bestand eines Hüttenbetriebes soll die Herangehensweise bei der Umsetzung einer solchen Aufgabenstellung, beginnend bei der Verfassung der Aufgabenstellung über mögliche Variantenstudien, materialtechnische Untersuchungen der Altbestandskonstruktion bis hin zur Fertigung und Montage dargestellt werden.
269

Vybrané části stavebně technologického projektu administrativní budovy s halou v Brně / Selected Parts of Construction Technology Project of an Office Building with a Hall in Brno

Bakyta, Marián January 2020 (has links)
This diploma thesis deals with selected parts of the construction technology project of an office building with a hall in Brno. The thesis contains a technical report, the coordination situation of the construction, the time and financial plan, the study of the main technological stages, the project of site equipment, the design of the main building machines and mechanisms, the time schedule, the budget, the technology prescription of flat single-roof, the quality control and test plan, the assessment of lifting mechanism selection and the design of rainwater capture for further use.
270

Školící středisko Zašová - stavebně technologický projekt / Training Center Zašová - construction technological project

Janíček, Jakub January 2014 (has links)
The subject of work is building-technology project Training center in Zasova. The study includes a technical report on the construction technological project, technical report of the site equipment project including a drawings, design of the main building machines, technical report of transport relations, itemized budget, the detailed time plan of the construction, technology regulations to of the selected construction processes, inspection and testing plans, occupational safety, environment, contract for construction works, major lifting mechanisms evaluation from an economic perspective.

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