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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.
351

Návrh uskladňovací nádrže / Design of storage tank

Sedmidubský, Petr January 2016 (has links)
The master thesis deals with design of storage tank for nitric acid. The first chapter introduces the problems of design, manufacture and operation of the storage tanks. The next section describes design calculation of storage tank according to standard EN 14015. Control of design calculation is performed by analysis FEM in program ANSYS Workbench 16.2. Thesis also includes basic drawing of storage tank.
352

Kondenzační parní turbína 70 MW / Condensing Steam Turbine 70 MW

Bezděk, Jakub January 2016 (has links)
Subject of this master's thesis is to design 70 MW single-casing steam turbine for the incernetion plant without reheating steam. The turbine has uncontrolled extraction points for another technology and axial flow outlet.
353

Porovnání ceny dopravní stavby se skutečně vynaloženými náklady v různém stupni rozestavěnosti / Comparing the Price of a Transportation Structure and the Actual Costs Incurred in Various Stages of Construction

Nezbeda, Jiří January 2017 (has links)
This diploma thesis deals with the calculation of the cost of the building work in order to create the price, which at the stage of the contract becomes a selling price, and the costs are fixed as a budget. The subject of this work is to monitor the development of costs in time so that the cost does not exceed the budget and the construction did not get into the negative result. Then set the price by its own methods (item budget, calculation according to budget indicators) and compare the prices and costs thus obtained from different phases of construction between each other and determine the differences. In this work is monitored and compared the cost of a construction contract and its costs in the construction stages. In the practical part,is used the method of direct comparison of cost and price values over time, in the form of different outputs from the controlling program and outputs from compiled item budget and the calculation of the construction. Analyzing the differences between these costs and their evolution over time by more detailed examination of item budgets and cost calculations, they determine the origin of these deviations. In conclusion, is proposed measures for a particular transport structure whitch was handled by the author as"master and co-ordinator of the construction".
354

Efficient Uncertainty Characterization Framework in Neutronics Core Simulation with Application to Thermal-Spectrum Reactor Systems

Dongli Huang (7473860) 16 April 2020 (has links)
<div>This dissertation is devoted to developing a first-of-a-kind uncertainty characterization framework (UCF) providing comprehensive, efficient and scientifically defendable methodologies for uncertainty characterization (UC) in best-estimate (BE) reactor physics simulations. The UCF is designed with primary application to CANDU neutronics calculations, but could also be applied to other thermal-spectrum reactor systems. The overarching goal of the UCF is to propagate and prioritize all sources of uncertainties, including those originating from nuclear data uncertainties, modeling assumptions, and other approximations, in order to reliably use the results of BE simulations in the various aspects of reactor design, operation, and safety. The scope of this UCF is to propagate nuclear data uncertainties from the multi-group format, representing the input to lattice physics calculations, to the few-group format, representing the input to nodal diffusion-based core simulators and quantify the uncertainties in reactor core attributes.</div><div>The main contribution of this dissertation addresses two major challenges in current uncertainty analysis approaches. The first is the feasibility of the UCF due to the complex nature of nuclear reactor simulation and computational burden of conventional uncertainty quantification (UQ) methods. The second goal is to assess the impact of other sources of uncertainties that are typically ignored in the course of propagating nuclear data uncertainties, such as various modeling assumptions and approximations.</div>To deal with the first challenge, this thesis work proposes an integrated UC process employing a number of approaches and algorithms, including the physics-guided coverage mapping (PCM) method in support of model validation, and the reduced order modeling (ROM) techniques as well as the sensitivity analysis (SA) on uncertainty sources, to reduce the dimensionality of uncertainty space at each interface of neutronics calculations. In addition to the efficient techniques to reduce the computational cost, the UCF aims to accomplish four primary functions in uncertainty analysis of neutronics simulations. The first function is to identify all sources of uncertainties, including nuclear data uncertainties, modeling assumptions, numerical approximations and technological parameter uncertainties. Second, the proposed UC process will be able to propagate the identified uncertainties to the responses of interest in core simulation and provide uncertainty quantifications (UQ) analysis for these core attributes. Third, the propagated uncertainties will be mapped to a wide range of reactor core operation conditions. Finally, the fourth function is to prioritize the identified uncertainty sources, i.e., to generate a priority identification and ranking table (PIRT) which sorts the major sources of uncertainties according to the impact on the core attributes’ uncertainties. In the proposed implementation, the nuclear data uncertainties are first propagated from multi-group level through lattice physics calculation to generate few-group parameters uncertainties, described using a vector of mean values and a covariance matrix. Employing an ROM-based compression of the covariance matrix, the few-group uncertainties are then propagated through downstream core simulation in a computationally efficient manner.<div>To explore on the impact of uncertainty sources except for nuclear data uncertainties on the UC process, a number of approximations and assumptions are investigated in this thesis, e.g., modeling assumptions such as resonance treatment, energy group structure, etc., and assumptions associated with the uncertainty analysis itself, e.g., linearity assumption, level of ROM reduction and associated number of degrees of freedom employed. These approximations and assumptions have been employed in the literature of neutronic uncertainty analysis yet without formal verifications. The major argument here is that these assumptions may introduce another source of uncertainty whose magnitude needs to be quantified in tandem with nuclear data uncertainties. In order to assess whether modeling uncertainties have an impact on parameter uncertainties, this dissertation proposes a process to evaluate the influence of various modeling assumptions and approximations and to investigate the interactions between the two major uncertainty sources. To explore this endeavor, the impact of a number of modeling assumptions on core attributes uncertainties is quantified.</div><div>The proposed UC process has first applied to a BWR application, in order to test the uncertainty propagation and prioritization process with the ROM implementation in a wide range of core conditions. Finally, a comprehensive uncertainty library for CANDU uncertainty analysis with NESTLE-C as core simulator is generated compressed uncertainty sources from the proposed UCF. The modeling uncertainties as well as their impact on the parameter uncertainty propagation process are investigated on the CANDU application with the uncertainty library.</div>
355

Zur Berechnung von Spannungs- und Deformationsfeldern an Interface-Ecken im nichtlinearen Deformationsbereich auf Parallelrechnern

Scherzer, M., Meyer, A. 30 October 1998 (has links)
Using material models on the basis of the flow theory of plasticity the asymptotic behaviour of solid mechanics solutions in crack tips, interface corners etc. strongly depends on the local realized load trajectory. For incrementally proportional load paths the equations determining the asymptotic fields are very simple ones. The paper considers two-dimensional statements in the neighbourhood of an interface corner consisting of two material ranges. At a distance from the corner the finite element nodes of a regular net are established in a polar co-ordinate system together with the displacement degrees of freedom. The main idea of the presented singular and non-singular stress and deformation field calculation at interface corners characterizes an replacement of the corner neighbourhood effect to the surrounding body by introducing stiffness actions which in usual manner can be assembled together with the other element stiffness matrices to the global stiffness matrix of the body. According to this there exists an in teresting invariant stiffness independence in corner and crack neighbourhoods. The applied technique allows extensions to non-proportional local load increments simplifying the mathematical calculations for the presentation of stress and strain fields in this general case. All computations are made on modern parallel computers. Concrete examples show the advantages of the presented approach.
356

Zero in on Key Open Problems in Automated NMR Protein Structure Determination

Abbas, Ahmed 12 November 2015 (has links)
Nuclear magnetic resonance (NMR) is one of the main approaches for protein struc- ture determination. The biggest advantage of this approach is that it can determine the three-dimensional structure of the protein in the solution phase. Thus, the natural dynamics of the protein can be studied. However, NMR protein structure determina- tion is an expertise intensive and time-consuming process. If the structure determi- nation process can be accelerated or even automated by computational methods, that will significantly advance the structural biology field. Our goal in this dissertation is to propose highly efficient and error tolerant methods that can work well on real and noisy data sets of NMR. Our first contribution in this dissertation is the development of a novel peak pick- ing method (WaVPeak). First, WaVPeak denoises the NMR spectra using wavelet smoothing. A brute force method is then used to identify all the candidate peaks. Af- ter that, the volume of each candidate peak is estimated. Finally, the peaks are sorted according to their volumes. WaVPeak is tested on the same benchmark data set that was used to test the state-of-the-art method, PICKY. WaVPeak shows significantly better performance than PICKY in terms of recall and precision. Our second contribution is to propose an automatic method to select peaks pro- duced by peak picking methods. This automatic method is used to overcome the limitations of fixed number-based methods. Our method is based on the Benjamini- Hochberg (B-H) algorithm. The method is used with both WaVPeak and PICKY to automatically select the number of peaks to return from out of hundreds of candidate peaks. The volume (in WaVPeak) and the intensity (in PICKY) are converted into p-values. Peaks that have p-values below some certain threshold are selected. Ex- perimental results show that the new method is better than the fixed number-based method in terms of recall. To improve precision, we tried to eliminate false peaks using consensus of the B-H selected peaks from both PICKY and WaVPeak. On average, the consensus method is able to identify more than 88% of the expected true peaks, whereas less than 17% of the selected peaks are false ones. Our third contribution is to propose for the first time, the 3D extension of the Median-Modified-Wiener-Filter (MMWF), and its novel variation named MMWF*. These spatial filters have only one parameter to tune: the window-size. Unlike wavelet denoising, the higher dimensional extension of the newly proposed filters is relatively easy. Thus, they can be applied to denoise multi-dimensional NMR-spectra. We tested the proposed filters and the Wiener-filter, an adaptive variant of the mean-filter, on a benchmark set that contains 16 two-dimensional and three-dimensional NMR- spectra extracted from eight proteins. Our results demonstrate that the adaptive spatial filters significantly outperform their non-adaptive versions. The performance of the new MMWF* on 2D/3D-spectra is even better than wavelet-denoising. Finally, we propose a novel framework that simultaneously conducts slice picking and spin system forming, an essential step in resonance assignment. Our framework then employs a genetic algorithm, directed by both connectivity information and amino acid typing information from the spin systems to assign the spin systems to residues. The inputs to our framework can be as few as two commonly used spectra, i.e., CBCA(CO)NH and HNCACB. Different from existing peak picking and resonance assignment methods that treat peaks as the units, our method is based on slices, which are one-dimensional vectors in three-dimensional spectra that correspond to certain (N, H) values. Experimental results on both benchmark simulated data sets and four real protein data sets demonstrate that our method significantly outperforms the state-of-the-art methods especially on the more challenging real protein data sets, while using a less number of spectra than those methods. Furthermore, we show that using the chemical shift assignments predicted by our method for the four real proteins can lead to accurate calculation of their final three-dimensional structures by using CS-ROSETTA server.
357

Energiberäkningar, energiuppföljningar och systemlösningar : Skanskas flerbostadshus i Stockholmsområdet

Haddad, Anthony January 2020 (has links)
Syftet med projektet är att analysera avvikelser mellan beräknad och uppmätt energianvändning för ett antal flerbostadshus i Stockholm. Detta är ett ämne som har uppmärksammats av myndigheter och företag, samtidigt som att energikraven blir ständigt tuffare. Av Sveriges totala energitillförsel används cirka 40 procent för drift och uppvärmning av byggnader, vilket innebär att byggsektorn bör arbeta aktivt med att minska energianvändningen och spela en stor roll i omställningen mot klimatneutralitet år 2045 för Sverige. Målet med projektet är att identifiera bidragande faktorer till avvikelser mellan energiberäkning och energianvändning för utvalda projekt, samt att ta fram förslag på förbättringsåtgärder som bidrar till förbättrade energiberäkningar och minskad energibehov. Metoden som används är att först analysera storlek på objekten för att sedan analysera den totala avvikelsen för dessa objekt på årsbasis och månadsbasis. Den totala avvikelsen analyseras på årsbasis, sedan kartläggs den månatliga förbrukningen i fyra poster: fastighetsel, värme, tappvarmvatten och hushållsel. En ny simulering och energiberäkning utförs på ett utvalt projekt med fokus riktad på orsaker till avvikelser. Resultatet visar att den mest bidragande faktorn till avvikelser är högre VVC-förluster, högre inomhustemperatur under uppvärmningssäsongen, lägre internvärme och högre ventilationsflöde. Vidare visar studien att det är möjligt att hitta orsakerna till avvikelse genom att enbart undersöka mätdata, om det är bra mätningsunderlag. / The purpose of the project is to analyze deviations between calculated and measured energy consumption for several apartment buildings in Stockholm. This is a topic that has been brought to the attention of authorities and companies, while at the same time the energy requirements are becoming increasingly tough. About 40 percent of Sweden's total energy supply is used for operation and heating of buildings, which means that the construction sector needs to work actively to reduce energy consumption and play a major role in the change towards climate neutrality in 2045 for Sweden. The aim of the project is to identify contributing factors to deviations between energy calculation and energy consumption for selected projects, and to develop proposals for improvement measures that contribute to improved energy calculations and reduced energy consumption. The method used is to first analyze the size of the objects and then to analyze the total deviation of these objects on a yearly and monthly basis. The total deviation is analyzed on an annual basis, then the monthly consumption is mapped into four items: real estate electricity, heating, domestic hot water and household electricity. A new simulation and energy calculation are performed on a selected project with a focus on causes of deviations. The result shows that the most contributing factor to deviations is higher VVC losses, higher indoor temperature during the heating season, lower internal heat and higher ventilation flow. Furthermore, the study shows that it is possible to find the causes of deviation by examining measurement data only if there is good measurement basis.
358

Praktisk Lastnedräkning och Stomstabilitet enligt Eurokoder / Practical Load Distribution and Structure Stability according to Eurocodes

Hansson, Henrik, Ludvigsson, Martin January 2015 (has links)
Eurokoderna som utgör svenska normer för verifiering av bärförmåga, stadga och beständighet är i en fortgående utvecklingsfas och är ibland svåra och tidsödande att tillämpa i konstruktionsarbetet. Normerna anpassas kontinuerligt efter att frågor debatteras i branschen och det är viktigt att användarna av Eurokoderna håller sig uppdaterade. Svårtolkade begrepp och definitioner tillsammans med en omständig struktur i Eurokoderna skapar merarbete för användarna. Detta examensarbete sammanställer nödvändig information samt undersöker och utvecklar tillhörande begrepp för två ämnen, lastnedräkning och stomstabilitet. Examensarbetet kommer likt en handbok kunna användas i vardagligt konstruktörsarbete för att snabbt hitta rätt i Eurokoderna och bidra till att reda ut oklarheter kring de två berörda ämnena. Beräkningsexempel är upprättade som praktisk vägledning för respektive ämne där Eurokoderna tillämpas och hänvisas till. Examensarbetet är inriktat på handberäkningar. Dessa handberäkningar kan ligga till grund för initiala bedömningar av ett bärverks dimensioner och övergripande stabilitet men även vara ett stöd i beräkningar i bygghandlingsskeden. / The Eurocodes, which serve as the Swedish standards for verification of mechanical resistance and stability, are in an ongoing development phase and are sometimes difficult and time consuming to apply in the design process. The standards are continuously adapted to issues debated in the industry and it is important that users of the Eurocodes keep themselves up to date. Indistinct terms and definitions in the Eurocodes create, together with an inconvenient structure, extra work for users. This thesis compiles the necessary information and examines and elaborates terms related to two topics, load distribution and structure stability. Similar to a handbook, this thesis can be used in designer’s everyday work to quickly find the right Eurocodes and help sort out the confusion related to the topics in this thesis. Calculation examples are given as a practical guide where Eurocodes are applied and referred to. The thesis is focused on hand calculations. These hand calculations could act as a base for initial assessments concerning structure dimensions and overall stability as well as a guide during final calculations for construction drawings.
359

Study on the Dynamic Control of Dam Operating Water Levels of Yayangshan Dam in Flood Season

Bramsäter, Jenny, Lundgren, Kajsa January 2015 (has links)
Water levels up- and downstream of dams are strongly affected by water levels in the reservoir as well as the discharge of the dam. To ensure that no harm comes to buildings, bridges or agricultural land it is important to ensure that the water level in the reservoir is adjusted to handle large floods. This report studies within what range the water level in the reservoir of the Yayangshan dam, located in Lixian River, can vary without causing any flooding downstream the dam or at the Old and New Babian Bridge located upstream the dam. By calculation of the designed flood, flood routing- and backwater computation, initial water level ranges in the reservoir have been set for the pre-flood, main flood and latter flood season for damages to be avoided. Due to the far distance between the dam site and the bridges, backwater effects had no influence on the limitations of the initial water level in the reservoir.
360

Kostnadsuppföljning avproduktionskalkyler / Follow-up of deviations from calculated production cost

Gustafsson Östberg, Malin January 2011 (has links)
Calculations are an important part of planning around a construction project. From concept to completion of the project calculation is a tool to try to predict the actual cost. During the production stage in particular, deviations occur which makes the actual cost different from the calculations.This thesis is done in collaboration with JM Residential Stockholm. The study includes a cost follow-up in which a comparison was made between the calculated production cost and actual cost for the five projects. The aim of the study was to observe the most common reasons that a project deviates from the calculated production cost and then summing these causes in a number of categories. The survey covers a limited number of accounts for each project. Information on deviations has been retrieved from cross-checking with calculations, and from interviews with those responsible for each project. The work also explains how the process of calculation is done, from early planning through to production.

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