Дисертації з теми "Calculation of the mode"
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1
Bruggmann, Guido. "Observation and model calculation of solar microwave bursts /." Bern, 1990. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
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Rubio, Pedro, Francisco Fernandez, and Francisco Jimenez. "REAL TIME C BAND LINK BUDGET MODEL CALCULATION." International Foundation for Telemetering, 2016. http://hdl.handle.net/10150/624184.
Повний текст джерелаАнотація:
The purpose of this paper is to show the integration of the transmission gain values of a
telemetry transmission antenna according to its relative position and integrate them in the C band
link budget, in order to obtain an accuracy vision of the link.
Once our C band link budget was fully performed to model our link and ready to work in real
time with several received values (GPS position, roll, pitch and yaw) from the aircraft and other
values from the Ground System (azimuth and elevation of the reception telemetry antenna), it
was necessary to avoid a constant value of the transmitter antenna and estimate its values with
better accuracy depending of the relative beam angles between the transmitter antenna and
receiver antenna. Keeping in mind an aircraft is not a static telecommunication system it was
necessary to have a real time value of the transmission gain.
In this paper, we will show how to perform a real time link budget (C band).
3
Mohamed, Amer. "Load Calculation and Simulation of an Asphalt Roller." Thesis, Blekinge Tekniska Högskola, Avdelningen för maskinteknik, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-4174.
Повний текст джерелаАнотація:
Free body diagrams of an Asphalt Roller were designed for several load cases and used for an optimisation study. Assumptions for the load calculations for each load case were carried out in MATLAB®. The Roller was built in I-DEAS® and the results were compared with the theoretical resultsF.B.D av en Asfalt Vältar designerades för olika last fall och användas för en optimisation studier. Antagandena för de olika last beräkningarna utfördas i MATLAB. Vältar byggdes i I-DEAS och resultaten jämfördes med de teoretiska.
Kungsmarks vägen 97 37144 Karlskrona - Sweden Telefon 045510316
4
Wigmore, Ioan Tomos. "Automated calculation of one-loop processes within MadGolem." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/7967.
Повний текст джерелаАнотація:
In the current LHC era, a vast number of models for BSM physics are being tested. For predictions accurate enough to match experimental errors, theoretical calculations have to go beyond LO estimates. However, calculating one-loop corrections in BSM models involves many new particles with specific model dependent properties. Therefore, they are done largely by hand, or in partially–automated ways. I present a fully automated tool for the calculation of generic massive one-loop Feynman diagrams with four external particles, implemented as a module within the fully automated MadGolem framework. With this one can compute the NLO–QCD corrections to generic BSM heavy resonance production processes, for example in the context of supersymmetric theories.
5
Wiegmann, Dirk. "An activity-based cost model for design-concurrent calculation." Thesis, This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-03032009-040709/.
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FERREIRA, JORGE LUIZ DE ALMEIDA. "A MODEL TO PREDICT UNCERTAINTY FOR FATIGUE DAMAGE CALCULATION." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1997. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=24799@1.
Повний текст джерелаАнотація:
O presente trabalho tem como objetivo deduzir, implementar e validar um modelo para avaliar o valor médio e a variância do dano por fadiga em estruturas sujeitas a carregamentos aleatórios. Para isto, a técnica de aproximação da média e da variância através da expansão em série de Taylor foi aplicada ao conjunto de equações do método epsilon-N e à regra de acúmulo de dano de Palmgren-Miner. O modelo proposto permite avaliar o comportamento estatístico das gamas de tensão localizadas, das gamas de deformações localizadas e do dano propriamente dito.
O modelo proposto possibilita a combinação dos fatores aleatórios associados à história de carregamento e ao comportamento mecânico do material. Isto permite avaliar a dispersão do dano sob um aspecto mais amplo, quantificando de forma independente as incertezas oriundas do comportamento aleatório do material e da história de carregamento.
A fim de avaliar o modelo proposto, foram utilizadas 20 histórias de carregamento diferentes. Estas histórias foram combinadas à dois níveis distintos de dispersões das propriedades mecânicas do material. A comparação das estatísticas obtidas analiticamente com aquelas estimadas através da técnica de simulação de Monte Carlo demostraram a viabilidade da utilização do modelo proposto.
Um estudo bastante completo foi realizado com relação à influência da história de carregamento sobre a dispersão do dano. Por este estudo verificou-se que a dispersão na previsão do dano provocado por trechos distintos de histórias são fortemente dependentes do tamanho da amostra. Para os casos estudados, verificou-se que trechos amostrados com menos de 3000 picos conduzem a dispersões superiores à 10 por cento , para histórias estritamente estacionárias, e superiores à 20 por cento, para histórias estacionárias num sentido amplo.
Após estudar o comportamento estatístico do dano acumulado e de seu valor crítico para a iniciação de uma trinca de fadiga, foram utilizados dois modelos analíticos distintos para a previsão da confiabilidade de projetos à fadiga. Estes modelos foram desenvolvidos supondo a distribuição de Weibull e a lognormal.
A validação destes modelos foi realizada comparando-se os resultados estimados analiticamente com seus correspondentes obtidos por simulação de Monte Carlo. A comparação das curvas de confiabilidade obtidas analiticamente com as curvas obtidas por simulação de Monte Carlo mostrou que o modelo baseado na distribuição lognormal é o mais indicado para a previsão da confiabilidade de projetos à fadiga.The present work is concerned with the development and the validation of a model to evaluate the average and the variance of the fatigue damage in structures subjected to random loading. The technique of the approximation of these statistics through of the expansion into Taylor series was applied to the set of equations that describe the epsilon-N method and the Palmgren-Miner rule. The proposed model allows the evaluation of the statistical behavior of the notch stress ranges, of the notch strain ranges and of the cumulative fatigue damage. The developed model allows the combination of random factors associated to loading histories and to the behavior of the material. In other words, the model estimates the dispersion of the fatigue damage under an extensive aspect, quatifying separately the contributions derives from the dispersion associated to sources of variation of the material behavior and the loading histories. In order to evaluate the proposed model, 20 random loading histories were combined to two levels of dispersion of the material properties. The combination allowed the study of the model under several situations. The performance of the model was evaluated by comparisons with the Monte Carlo technique. The agreement of the proposed model with the Monte Carlo technique was considered good. An extensive study was realized concerning the influence of the random loading on the dispersion of the damage prediction. It was observed that the dispersion is strongly associated to sample s size. From the cases studied it was observed that sample s blocks with less than 3000 peak might conduct to dispersions larger than 10 per cent, for strictly stationary processes, and larger than 20 per cent, for wide-sense stationary processes. After studying the statistical behavior of the cumulative fatigue damage and of its critical value to initiate a fatigue crack, two analytical model for fatigue reliability analysis were presented. These models are developed under the assumption that cumulative fatigue damage and its critical value follow a lognormal or a Weibull distribution. To verify the predicted results the Monte Carlo analysis was used. From this analysis it was verified tha the interference statistical model, based on a lognormal distribution, describes better the behavior of the fatigue s reliability.
7
Mujagic, Ubejd. "Strength Calculation Model for Standoff Screws in Composite Joists." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/35960.
Повний текст джерелаАнотація:
The objective of the research reported herein is to present a comprehensive evaluation of all available experimental data from push-out tests utilizing the ELCO Grade 8 standoff screws. The goal is to develop a strength prediction equation and determine reliability parameters compatible with the Load Factor Resistance Design (LRFD) procedure that would allow the use of this shear connector in design of composite floor systems.
The study considers results from push-out tests using this type of screw reported by Hankins et al. (1994), Alander et al. (1998), Webler et al. (2000), and Mujagic et al. (2000). Further, this study identifies the limitations in earlier approaches aimed at predicting the strength of standoff screws. An improved strength prediction model is developed that considers all applicable limit states and determines maximum strength of a connector. A reliability study was also conducted to derive strength reduction factors to be used in design. Parameters considered in the model include deck type and geometry, screw height, concrete compressive strength, top chord angle yield strength, and stand-off screw rupture strength. Results from strength prediction model were compared with results from composite joist tests.Master of Science
8
Eriksen, Håkon. "Development of Calculation Model for Heat Exchangers in Subsea Systems." Thesis, Norwegian University of Science and Technology, Department of Energy and Process Engineering, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9115.
Повний текст джерелаАнотація:
Subsea processing can make production from otherwise unprofitable fields profitable. In subsea processing controlled cooling of the process fluid will often be required. Robust and simple solutions are desirable in subsea processing. Coolers that rely on natural convection from the surrounding seawater are therefore interesting, but control of the process fluid outlet temperature is hard to obtain in such coolers. In this study a calculation model for subsea coolers has been developed. The commercial software MATLAB has been used for developing a program. Heat transfer and frictional pressure drop correlations have been studied and recommendations are made for the model. The model is based on tubes in parallel, and the tubes can be oriented vertically or horizontally. The program allows for open, semi-open and closed arrangements on the waterside, and both natural and forced convection is implemented. The program has been tested through simulations of two test cases and found to be performing as desired.
9
Oyama, Norihiro. "Direct Numerical Calculation on the Collective Motion of Model Microswimmers." 京都大学 (Kyoto University), 2017. http://hdl.handle.net/2433/225640.
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Berglund, Matilda. "Implementation of a risk calculation model incorporating optimal liquidation strategies." Thesis, Umeå universitet, Institutionen för fysik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-125480.
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Tegbrant, Kerstin. "Cost-effectiveness of ergonomic interventions - Evaluation of a calculation model." Thesis, KTH, Skolan för kemi, bioteknologi och hälsa (CBH), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-262006.
Повний текст джерелаАнотація:
Several studies have shown that the work environment affects company performance. The managers are seldom aware to which extent work environment problems affect productivity, quality of delivery and sick-leave in their organisation. The present literature study showed that improvements regarding physical ergonomics generally are shown to be cost-effective. The most beneficial way of working is through proactive measures interactively with employees. An efficient, systematic way of performing risk assessments and interventions reduce the need for a calculation method. This study identified propositions for properties of calculation methods. These propositions were : “Simplicity, high usability”, “Right content for the target group”, “High ability to measure risk”, “Focus on staff”, “Correct standardised values”, “Right focus” and “Optimal design”. Scania CV, a producer of trucks and buses, has developed a calculation model for cost-effectiveness of ergonomic interventions. Evaluation of this model with semi-structured interviews showed agreement regarding the need of a simplified calculation method, based on systematic risk assessments.Ett flertal studier har visat att arbetsmiljön påverkar företags effektivitet. Företagsledningen är sällan medveten om till vilken grad arbetsmiljö-problem påverkar produktivitet, kvalitet och sjukfrånvaro. Litteraturstudien i detta projekt visade att förbättringar inom ergonomi generellt sett är kostnadseffektiva. Det är mest gynnsamt att arbeta proaktivt samt participativt, det vill säga i samarbete med medarbetarna på den lokala avdelningen. Ett effektivt, systematiskt arbete med riskbedömningar och interventioner minskar behovet av att göra en beräkning av lönsamheten. Propositioner för egenskaper hos kostnadseffektiva beräkningsmetoder togs fram i denna studie. Dessa propositioner var; ” Enkelhet och god användbarhet”, ”rätt innehåll för målgruppen”, ”hög förmåga att bedöma risk”, ”personalfokus”, ”korrekta standardiserade värden”, ”rätt fokus” och ”optimal design”. Scania CV, producent av lastbilar och bussar, har tagit fram en beräkningsmodell för kostnadseffektivitet hos ergonomiska interventioner. Utvärderingen av denna modell med semistrukturerade intervjuer visar god samstämmighet i att det behövs enkla kalkylmetoder som grundar sig på systematiska riskbedömningar.
12
Jelínková, Jana. "Kalkulace vnitropodnikové ceny jednotlivých výkonů ve vybraném podniku." Master's thesis, Vysoká škola ekonomická v Praze, 2008. http://www.nusl.cz/ntk/nusl-11233.
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Wolfe, Carl Eric. "Calculation of some selected isospin-breaking observables in the standard model." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0002/NQ43456.pdf.
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Skjelbred, Kristin Marie. "Calculation of Transition Moments Using the Extended Coupled Cluster Model ECC2." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for kjemi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-26236.
Повний текст джерелаАнотація:
As a part of the ongoing development of the multi level coupled cluster (MLCC) model ECC2, the work presented here is focused on obtaining transition moments associated with certain excitation energies. The ECC2 model divides the system into two subsystems where different levels of theory are used. The idea behind the method is to use a high level of theory on a small part of the system, the active space, and a lower level on the bigger part, the inactive space. Specifically the coupled cluster singles and doubles (CCSD) is used as the higher level, while the approximate model CC2 is used as the lower level. This allows for retention of computational accuracy while reducing the complexity and consequently the cost of the calculations, assuming the active space has been chosen correctly.An important part of MLCC theory is the partitioning of the system and how orbitals are described. Here Cholesky decomposition has been chosen, both be- cause it reduces computational complexity and because it lets the user use his chemical expertise. The former is a consequence of when the positive semidefinite density matrix is decomposed into a lower triangular matrix and its tranpose, and then used to generate localized orbitals. The orbitals are assigned to atomic cen- ters, and since it is up to the user to choose which orbitals are part of the active space, use of chemical intuition is key. Transition moments are a local property and limiting the active space to the orbitals taking part in the corresponding ex- citation leads to a great reduction in scaling.A pilot version of the model is tested and compared to CCSD and CC2. The outcome of the testing suggests that the current version of the code still contains bugs and needs to be modified, but also show that parts of the model have suc- cessfully been implemented. The accuracy of the results presented here are not discussed, as they have proven to be different than expected and suggest further testing and debugging of the code, before the ECC2 transition moments are pub- lished.
15
Birindelli, Gabriele. "Entropic model for dose calculation in external beam radiotherapy and brachytherapy." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0057.
Повний текст джерелаАнотація:
Ce travail est dédié au développement et à la validation d'un nouvel algorithme de résolution de l’équation de Boltzmann sur une grille cartésienne pour le transport et le dépôt d'énergie de particules énergétiques et de rayons X dans les tissus humains. Ce modèle basé sur une fermeture entropique fournit un outil mathématique efficace permettant de calculer la dose délivrée avec une précision comparable à celle des codes référents de Monte Carlo (MC) en un temps de calcul fortement réduit et sans exigence de puissance de calcul.Contrairement aux méthodes basées sur une discrétisation angulaire aux ordonnées discrètes de la solution, telles que le modèle développé dans le logiciel Acuros®, le modèle entropique est basé sur l’écriture d’un nombre réduit d’équations aux moments pour les électrons et les photons dont la fermeture est assurée par le H-théorème de Boltzmann. En conservant une bonne précision de calcul, l'algorithme peut simuler différentes techniques de traitement telles que la radiothérapie externe - éventuellement en présence de champ magnétique pour la radiothérapie guidée par IRM - la curiethérapie ou la radiothérapie intra-opératoire. Le modèle a été comparé aux simulations MC en utilisant le code PENELOPE ; il a montré une excellente précision et de bonnes performances pour différents matériaux et structures géométriques.Le protocole de validation mis en place a consisté à simuler les distributions de doses dans des fantômes numériques complexes en termes de géométries (hétérogénéités) et de composition (os, poumons, air, prothèses). Pour la curiethérapie et la radiothérapie externe, des simulations réalistes basées sur des tomographies et utilisant l'espace de phase réel de la source ont été effectuées.Le code est capable de calculer des distributions de dose tridimensionnelles avec des voxels de 1mm x 1mm x 1mm sans incertitudes statistiques en quelques secondes au lieu de plusieurs minutes comme PENELOPE le propose. Dans les applications à la curiethérapie, nous montrons que les distributions de dose diffèrent significativement de celles calculées avec les approximations TG-43, grâce à une prise en compte plus précise des inhomogénéités et des compositions chimiques des matériaux ainsi que des forts gradients de densité. Pour les deux applications, le modèle entropique montre un excellent accord avec les calculs PENELOPE dans le critère de mesure d’erreur gamma-index 1% / 1 mm.Cette thèse de doctorat présente les bases mathématiques et les différentes étapes d'optimisation et de validation du modèle entropique pour la radiothérapie. Les comparaisons avec les simulations MC démontrent une excellente précision et efficacité du modèle. Grâce au temps de calcul considérablement réduit et à sa précision, ce modèle est un candidat prometteur pour devenir un algorithme de calcul de dose en temps réel référentThis work is dedicated to development of a completely new Grid-Based Boltzmann Solver (GBBS) for the transport and energy deposition by energetic particles and x-rays in human tissues. The entropic closure and structured mathematical formulation provide an efficient framework enabling calculations of the delivered dose with an accuracy comparable to Monte Carlo (MC) codes in a strongly reduced computational time and without any special processing power requirement.In contrast to discrete ordinates angular discretization methods, such as Acuros®, the entropic model is based on a reduced number of moment equations for the electrons and photons closed with Boltzmann’s H-theorem. Keeping a good accuracy of calculations, the algorithm can simulate different treatment techniques such as the external radiotherapy even in presence of magnetic field (e.g., MRI&-guided radiotherapy), brachytherapy or intra-operative radiation therapy. The model has been compared with the full MC simulations by using the code PENELOPE and showed a good accuracy and performance for different materials and geometric structures.The validation procedure consisted in simulating dose distributions in complex numerical phantoms including a large number of heterogeneity shapes and materials such as bone, lung and air. For both, brachytherapy and external beam radiotherapy, simulations based on CT scans and using the real phase-space of the source, have been performed.The code is capable of calculating three-dimensional dose distributions with 1 mm3 voxels without statistical uncertainties in a few seconds instead of several minutes like PENELOPE. In brachytherapy applications the calculated dose distributions significantly differ from the ones calculated with the TG-43 approximations, thanks to a more accurate account for the material inhomogeneities and strong density gradients. For both applications the entropic model shows an excellent agreement with PENELOPE calculations within the 1%/1mm gamma-index criterion.This Ph. D. thesis presents the mathematical background and different steps of optimization and validation of the entropic model for the radiotherapy applications. Comparisons with the MC simulations demonstrates an excellent accuracy and efficiency of the model. Thanks to the significantly reduced computational time and its accuracy, this model is a promising candidate to become a real-time dose calculation algorithm
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Sohail, Raveed, and Sai Anuroop Nimmagadda Bhavani. "Calculation Method and Tool to Visualize Cable Harness Usage in Trucks." Thesis, Blekinge Tekniska Högskola, Institutionen för maskinteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-17754.
Повний текст джерелаАнотація:
Cable harness is an integral part of a modern-day automobile. The design of many mechanical components is based on the cable harness and hence it is important to accurately calculate the space occupied by cable harness. In this thesis, a theoretical model representing n arbitrarily sized cables was used to generate a packing of the cable harness, and the space occupied by them was calculated. The model was used to develop an algorithm that generated a feasible configuration and a container around that packing. The optimisation toolbox in MATLAB was also used to calculate the space and optimise the container size. A customised standalone tool was developed in MATLAB by utilising the established methods, that enables calculation of space occupied by cables at various points of interest along the truck chassis for Scania CV.
17
Loughman, Robert Paul 1971. "A spherical-shell radiative transfer model for the calculation of limb radiances." Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/288849.
Повний текст джерелаАнотація:
A new spherical-shell radiative transfer model has been developed, with particular emphasis on the accurate calculation of the scattered radiance in the limb of the atmosphere. The model accounts for the spherical geometry of the atmosphere for all orders of scattering, but neglects the influence of polarization and refraction. Solutions are obtained by the successive orders of scattering method for several solar zenith angles simultaneously, using the inherent symmetry of the radiation field about the sub-solar point. The model is described by comparing and contrasting it with the model previously presented by Thome (1990) and Herman et al. (1994). The new model is tested against independent calculations to demonstrate the accuracy of the method. Its results are compared with the Monte Carlo calculations presented by Adams and Kattawar (1978) and Kattawar and Adams (1978) for a homogeneous atmosphere. Agreement is observed to within the stated statistical error of the Adams and Kattawar (1978) and Kattawar and Adams (1978) results for all lines of sight, including those in the limb. Comparisons are also made to the results obtained by the Herman et al. (1994) code for a more realistic atmospheric profile. These comparisons reveal excellent agreement outside the limb of the atmosphere, but some significant disagreement in the limb, which must be investigated further. Finally, preliminary results are presented that demonstrate the sensitivity of limb scattered radiances to changes in the ozone profile. Limb radiances are shown to be sensitive to a relatively small change in the ozone abundance in a thin layer of the atmosphere. However, the observed sensitivity is shown to decrease when aerosol scattering is added to the model atmosphere.
18
Hoshmeh, Abdullah, and Uwe Schmidt. "A Full Frequency-Dependent Cable Model for the Calculation of Fast Transients." Universitätsbibliothek Chemnitz, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-228649.
Повний текст джерелаАнотація:
The calculation of frequency-dependent cable parameters is essential for simulations of transient phenomena in electrical power systems. The simulation of transients is more complicated than the calculation of currents and voltages in the nominal frequency range. The model has to represent the frequency dependency and the wave propagation behavior of cable lines. The introduced model combines an improved subconductor method for the determination of the frequency-dependent parameters and a PI section wave propagation model. The subconductor method considers the skin and proximity effect in all conductors for frequency ranges up to few megahertz. The subconductor method method yields accurate results. The wave propagation part of the cable model is based on a cascaded PI section model. A modal transformation technique has been used for the calculation in the time domain. The frequency-dependent elements of the related modal transformation matrices have been fitted with rational functions. The frequency dependence of cable parameters has been reproduced using a vector fitting algorithm and has been implemented into an resistor-inductor-capacitor network (RLC network) for each PI section. The proposed full model has been validated with measured data.
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Wesslund, Lovisa. "Beräkningsmall för vindlast enligt Eurokoder samt jämförelsestudie av vindlastberäkningsmetoder." Thesis, KTH, Byggteknik och design, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-102022.
Повний текст джерелаАнотація:
Detta examensarbete har genomförts i samarbete med byggteknikavdelning på Ramböll Sverige AB, i Norrköping/Linköping. På företaget finns ett behov av att förenkla arbetet med vindlastberäkningar för hallbyggnader enligt Eurokoden. Idag använder företaget en förenklad metod som överdimensionerar. För att kunna göra en mer exakt beräkning helt enligt Eurokoden och effektivisera arbetet har det i detta examensarbete skapats en beräkningsmall för detta ändamål. Beräkningsmallen har tagits fram i programmet Microsoft Excel. För att också kunna se konsekvenserna av att jobba med en förenklad metod, har det utförts en jämförelsestudie mellan två befintliga projekt på företaget. Resultatet av jämförelsestudien visar på vad som är anledningen till skillnaden mellan det förenklade sättet, metod 1 och det mer exakta, metod 2. Rapporten innehåller en studie kring de faktorer som används vid beräkning av vindlast. Detta har gjorts för att kunna se vilken av faktorerna som bidrar till störst skillnad i resultat mellan de båda metoderna. Som grund till allt detta, innehåller rapporten också en teoretiskt bakgrund till hur vindlast ska dimensioneras enligt Eurokoden. Detta utgör första delen av rapporten.This study has been performed in a collaboration with the company Ramböll Sweden AB in Norrköping/Linköping. At the company there is a need to simplify calculations concerning the wind load on industrial buildings according to the Eurocode. Today the company uses a simplify method which result in an over-dimension. To make a more exact method in accordance to the Eurocode and increase the efficiency at the work, it has in this study created a calculation model for this purpose. The calculation model has been created in the program Microsoft Excel. To be able to see the consequences to work with a simplified method, it has been done a comparison study between two current project at the company. The results of the comparison study show the reason to the difference between the simplified method, method 1 and the more exact method, method 2. The report containing a study of the factors that uses in the calculations. This has been done to see which of the factors that contributes to the largest difference in result between the both methods. As the basis for all this, the report also contains a theoretical background about how the wind load should be dimensioned according to the Eurocode. This is the first part of this report.
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Olofsson, Jörgen. "Developing and evaluating dose calculation models for verification of advanced radiotherapy." Doctoral thesis, Umeå universitet, Institutionen för strålningsvetenskaper, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-841.
Повний текст джерелаАнотація:
A prerequisite for modern radiotherapy is the ability to accurately determine the absorbed dose (D) that is given to the patient. The subject of this thesis has been to develop and evaluate efficient dose calculation models for high-energy photon beams delivered by linear accelerators. Even though the considered calculation models are general, the work has been focused on quality assurance (QA) tools used to independently verify the dose for individual treatment plans. The purpose of this verification is to guarantee patient safety and to improve the treatment outcome. Furthermore, a vital part of this work has been to explore the prospect of estimating the dose calculation uncertainties associated with individual treatment setups. A discussion on how such uncertainty estimations can facilitate improved clinical QA procedures by providing appropriate action levels has also been included within the scope of this thesis. In order to enable efficient modelling of the physical phenomena that are involved in dose output calculations it is convenient to divide them into two main categories; the first one dealing with the radiation exiting the accelerator’s treatment head and a second one associated with the subsequent energy deposition processes. A multi-source model describing the distribution of energy fluence emitted from the treatment head per delivered monitor unit (MU) is presented and evaluated through comparisons with measurements in multiple photon beams and collimator settings. The calculations show close agreement with the extensive set of experimental data, generally within +/-1% of corresponding measurements. The energy (dose) deposition in the irradiated object has been modelled through a photon pencil kernel solely based on a beam quality index (TPR20,10). This model was evaluated in a similar manner as the multi-source model at three different treatment depths. A separate study was focused on the specific difficulties associated with dose calculations in points located at a distance from the central beam axis. Despite the minimal input data required to characterize individual photon beams, the accuracy proved to be very good when comparing the calculated results with experimental data. The evaluated calculation models were finally used to analyse how well the lateral dose distributions from typical megavoltage photon beams are optimized with respect to the resulting beam flatness characteristics. The results did not reveal any obvious reasons why different manufacturers should provide different lateral dose distributions. Furthermore, the performed lateral optimizations indicate that there is room for improved flatness performance for the investigated linear accelerators.
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Pařízková, Iva. "Matematický model teplárenské sítě." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-241664.
Повний текст джерелаАнотація:
This thesis is focused on creating an iterative model for thermal and hydraulic calculation of heating net in Visual Basic of Application. Flowing medium considered is hot water. Although data for heating network in Brno are recorded in this model, its use for any other heating network is possible. This model allows also calculation of minimal temperature of the source and calculation of heat loss of every consumer. This is very useful when considering, if supplying some of the consumers with the heat from a local source would not be more effective. The second part of this text is aimed to evaluation of different ways how to reduce the heat loss in heat network for source Červený mlýn. Both current situation and possibilities for the future are considered.
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Pykalová, Michala. "Kalkulační systém a jeho využití v řízení konkrétní firmy." Master's thesis, Vysoká škola ekonomická v Praze, 2008. http://www.nusl.cz/ntk/nusl-76884.
Повний текст джерелаАнотація:
The aim of the thesis was to analyse the costing system in Kasalova pila, s. r. o., to assess the complexity of the performed calculations to determine if the calculations are updated regularly. Further, it was examined the influence of costing system for management of the company. The thesis is divided into two main parts, theoretical and practical part. The theoretical part describes the main concepts of costing, cost classification methods, costing system and its components and structure. In the introduction of the practical part of this thesis is briefly described the company Kasalova pila, s. r. o. In the following chapters is described the costing model used by the example of a particular product. In conclusion of the thesis is reviewed the whole costing system and proposed several recommendations.
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Ismayilov, Orkhan. "Application of 3-D Analytical Model for Wellbore Friction Calculation in Actual wells." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for petroleumsteknologi og anvendt geofysikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-19398.
Повний текст джерелаАнотація:
With the increasing number of drilled ultra-extended reach wells and complex geometry wells, the drilling limitation caused by excessive torque and drag forces must be further investigated. The wellbore friction being a main limiting factor in extended reach well needs to be studied with the new developed models.This master thesis presents an application of the new 3-dimentional analytical model developed by Bernt S. Aadnøy in the synthetic test and four real wells. Quite diverse wellbore trajectory and depth has been chosen for a better evaluation and comparison of the model with the measured data. In order to investigate the potential and limitation of the model, torque and drag analysis during the different operations such as tripping in, tripping out, rotating off bottom, combined up/down were investigated. An application of the analytical model for wellbore friction analysis in the actual wells is very time consuming and requires a lot data/input manipulation. As a part of the thesis assignment, it was required to create simplified means for application and testing the analytical model. With visual basic application in Excel a simple torque and drag simulator was created purely based on the analytical model simple solution. Along with the analytical model the master thesis includes Wellplan software for torque and drag analysis in all the included test and actual wells. Along with this, the project has a brief literature study of 3D analytical model and torque and drag concept in general. The analytical model gives a reasonable torque and drag results. Based on comparison between the model and actual measurement, it has been observed that the analytical model simple solution in some cases may not precisely describe wellbore friction analysis. The discrepancy between Wellplan and the analytical model prediction occurs during the tripping in operations. Being a strong function of tension/compression in the drill string the analytical model for more accurate torque and drag prediction requires an application of the complete solution. The main challenge for this model is the complexity of its full application. There is an uncertainty regarding the model application in conjunction with drillstring effective tension. For the actual well application it is time consuming and requires drillstring effective tension analyzing which make the model disable for the real time analysis.The analytical model must be further investigated by application in the real well with good quality of measured data.
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Escudero, Torres Cuauhtémoc. "Numerical calculation model for the global analysis of concrete structures with masonry walls." Doctoral thesis, Universitat Politècnica de Catalunya, 2015. http://hdl.handle.net/10803/318158.
Повний текст джерелаАнотація:
The numerical simulation in the field of civil engineering, while widely used in structural design, has not benefited from the full potential offered by new technologies for the analysis and design of composite materials within the framework of the finite element, technologies that are already present in industries such as automotive, aerospace and shipbuilding.
This thesis is based on the numerical simulation, and emerges as the need to combine and improve existing technologies in the field of finite element analysis for composite materials, to assess the overall structural behavior of reinforced concrete buildings with masonry in-fills, and consequently, to support the derivation of rational rules for analysis and design purposes.
Prior to the beginning of this thesis, a huge concern was the large amount of computational resources needed for both solving systems of linear equations resulting from the use of the finite elements method, and for storing internal variables needed in the integration of constitutive models. Therefore, in this work, computational strategies used to enable the analysis of real life structures are also provided.
The simplicity required to handle meshes with high amount of finite elements pushed us to develop a new layered finite element, that can reproduce the non-linear behavior of its constituent materials when there are out-of-plane stresses, this, without having to introduce additional degrees of freedom. The finite element proposed has been com- pared to finite element with different kinematics obtaining excellent results.
The robustness and efficiency of the developed methodology for analysis of masonry and concrete buildings, is conditioned by the ability of using different patterns of steel reinforcement, which are typically presented in real life structures. That is why it has also been necessary to develop a computing program capable of reading both finite element meshes, and patterns of fibers represented with convex polygons, and as a result of areas intersections between polygons returns volumetric participation of fiber and matrix of constituents materials for each layer, in addition had to return the fiber orientation with respect to the local axis of the finite element.
The numerical results obtained have been compared in some cases with experimental results available in the literature, in other cases, with numerical results obtained using Building Codes, in both cases, there have been good agreement between them. Finally, it has been possible to characterize a representative medium-rise building of Mexico City using the capacity spectrum method. This method is widely used nowadays for the assessment of building behavior, since using fragility curves can represent the ability of a building to resist an earthquake.La simulación numérica en el campo de la ingeniera civil, aunque es ampliamente utilizada en el diseño estructural, no se ha beneficiado de todo el potencial que ofrecen las nuevas tecnologías para el análisis y diseño de materiales compuestos dentro del marco de los elementos finitos, tecnologías que ya están presenten en industrias como la automotriz, aeroespacial o la naval. Este trabajo de tesis esta basado en la simulación numérica, y surge como la necesidad de combinar y mejorar tecnologías existentes en el campo de los elementos finitos y de análisis de materiales compuestos, para conocer el comportamiento estructural global de los edificios de hormigón armado con rellenos de mampostería, y para apoyar en la derivación de reglas racionales con fines de diseño. Una preocupación previa al inicio de esta tesis doctoral, era la gran cantidad de recursos computacionales necesarios, tanto para la resolución de los sistemas de ecuaciones lineales resultantes con el uso del método de los elementos finitos, como para el almacenamiento de variables internas necesarias en la integración de modelos constitutivos. Por ello, dentro de este trabajo, también se proporcionan las estrategias computacionales usadas que permiten el análisis de estructuras de la vida real. La simplicidad requerida para el manejo de mallas con gran cantidad de elementos finitos lleva a desarrollar un elemento de l¿amina con diferentes capas, que pueda reproducir el comportamiento no lineal de sus materiales componentes cuando existen tensiones fuera del plano, sin que haya que introducir grados de libertad adicionales. El elemento finito propuesto ha sido comparado con elementos finitos de diferente cinemática obteniendo excelentes resultados. La robustez y eficiencia de la metodología desarrollada para el análisis de edificios de hormigón y mampostería, esta condicionada a la capacidad de utilizar los diferentes patrones de acero de refuerzo que típicamente se presentan en estructuras de la vida real. Es por ello que también ha sido necesario desarrollar un programa de computo capaz de leer tanto una malla de elementos finitos, como un patrón de fibras representado con polígonos convexos, y que mediante operaciones de intersecciones de ¿áreas entre polígonos, de como resultado la participación volumétrica de matriz y fibra de los materiales componentes por cada capa, además de la orientación de la fibra con respecto a los ejes locales del elemento finito. Los resultados numéricos obtenidos se han comparado con resultados experimentales presentes en la literatura, y con resultados numéricos obtenidos utilizando normas de construcción, en ambos casos, se han observado buenos ajustes entre ellos. Finalmente,ha sido posible caracterizar un edificio representativo ubicado en la Ciudad de México usando el método del espectro de capacidad. Dicho método es ampliamente utilizado hoy en día para el diseño y evaluación sismo-resistente de estructuras, ya que mediante el uso de curvas de fragilidad permite representar la susceptibilidad de una estructuraa ser dañada debido a un terremoto.
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Huo, Xi Ting (Bob). "New Model of Eddy Current Loss Calculation and Applications for Partial Core Transformers." Thesis, University of Canterbury. Electrical and Computer Engineering, 2009. http://hdl.handle.net/10092/3631.
Повний текст джерелаАнотація:
This thesis first explains the eddy current and the phenomenon of skin effect, where the resultant flux flows near the surface of the metal. A new flux direction perspective is created for steel laminations, from which derivations of the eddy current resistance and power losses in different directions are developed assuming uniform flux conditions. The developed method compares with a proposed theory through experimental data. The results from the comparison support the validity of the developed derivations. Two uniform flux generators and their billets construction are introduced. The power loss between two cubic billets with different orientations is compared. A Finite Element Analysis (FEA) program is used to show the difference between lamination alignments. To prove the validity of the developed theory, two experiments were performed using two different electroheating apparatus. The results give scale factors from which the theoretical values can be matched to the experimental ones. Due to the poorer construction of the first apparatus, the scale factor of measured to computed losses is 1.15. The scale factor for the second apparatus can be taken as unity, revealing a good match between theory and measurements. After verification of the developed equations for uniform flux experiments, the focus of the eddy current loss calculation turned to partial core transformers. The flux background of a cubical core is reviewed. Three key factors ( L', Kec and βa) are introduced into the eddy current power loss model. L' is a length which indicates the region of the flux spreading at the ends of the core. Kec as a ratio indicates how much of the main flux spreads at the ends of the core. βa is the ratio of the winding axial length and winding thickness. Using simulations from the Finite Element Analysis (FEA) program MagNet, a partial core side view with the flux distribution and flux density from two orthogonal angles is created. A flux linkage comparison between the experimental results and the returned values from MagNet verifies the high accuracy of the flux plot in MagNet. The eddy current power loss model is then built up with equations. The relationships amongst the three key factors are studied and confirmed using the experimental results. Normally, a partial core transformer uses a cylindrical partial core rather than a cubical partial core, to reduce the amount of winding material. Therefore, a further goal was to prove the developed model for cylindrical partial core transformers. The construction differences between the cubical and cylindrical core is discussed. The orthogonal flux assumptions for the cylindrical core in two directions are reviewed. The flux penetration between two adjacent blocks is considered and explained. The mathematical core loss model is created for a cylindrical core composing by ten blocks. Three tests were performed using the developed core loss model. The results visualize the power loss from the core by its temperature distribution, and consequently prove the validity of the developed core loss model. An eddy current loss comparison and the discussion are made between the previous method and the developed method. Overall, the results confirm a significant improvement using the developed core loss model, and a generic form of the partial core can be used for designing future models of partial core transformers which have a stacking factor greater than 0.96.
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Li, Thomas. "Developing a Bottom Up Cost Calculation Model and Methodology for Thermal Storage Applications." Thesis, KTH, Kraft- och värmeteknologi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-256006.
Повний текст джерелаАнотація:
Increasing storage for energy is one of the most important challenges today to overcome in order to enable higher penetration of renewable energy in the existing energy systems. Thermal storage is one category of energy storage that has been successfully demonstrated in a number of engineering projects and is showing promising potential in the future. However, a technology cannot be widespread if it is not economically feasible and sustainable in the long run. Bottom up cost analysis can be used to assess economic viability of a technology. For newer technologies, the top-down cost calculation is not always possible due to the limited amount of data. The aim of this thesis is to investigate the best practices in performing bottom up cost calculation and to propose a methodology with the purpose of enabling it to be implemented over thermal energy storage bottom up economic evaluations. To achieve this, two proven applications, molten salt storage for concentrated solar power and ice thermal storage for building cooling, were examined as the basis of the bottom up state of the art calculation models. It was found that in the ice storage case, the models were often done in a hybrid bottom up-top down approach which limits a fully detailed cost analysis. Instead these are referred as case studies instead because of the few elements needed in their calculation. The constructed specialized models and case studies are then compared against other external sources to validate the proposed economic analysis procedure. The numerical results showed some discrepancies when compared to external resources. A compilation of a general bottom up cost model with detailed step by step model to perform a bottom up calculation for thermal storages is finally proposed in this work.Att förbättra möjligheterna att lagra energi är en av dagens viktigaste utmaningar för att kunna öka andelen förnybar energi i vårt energisystem. Termisk energilagring eller värmelagring är en typ av energilagring som använts framgångsrikt i flera områden och visar hög potential i ett flertal ytterligare teknologier. En teknologi kan dock inte få en omfattande påverkan om den inte är ekonomiskt hållbar. En bottom-up kostnadsanalys kan användas för att uppskatta genomförbarheten för teknologin. För nya teknologier är en top-down kostnadsanalys inte alltid möjlig, vilket är beroende på den begränsade tillgången till data. Syftet med den här uppsatsen är att undersöka de vanligaste tillvägagångssätten i att utföra en bottom-up kostnadsanalys och föreslå en metodologi som har ändamålet att användas i bottom-up kostnadsanalyser för värmelagringstekniker. För att uppnå detta har två beprövade tekniker, smält saltlagring i koncentrerad solkraft och islagring för kylning av byggnader, undersökts som modeller för moderna bottom-up kostnadsanalyser. Efter undersökning fann man att i islagringsteknologi genomförs kostnadsanalysen vanligen i ett hybrid bottom up-top down upplägg, vilket begränsar möjligheten att rekonstruera en fullt detaljerad bottom-up kostnadsanalys. Dessa kommer istället att refereras som fallstudier eftersom endast ett fåtal objekt behövdes i en kostnadsberäkning. Specialiserade kostnadsmodeller som konstruerats och fallstudier jämförs med externa källor för att bekräfta den föreslagna analysproceduren för kostnadsberäkningar. Jämförelsen med externa källor visade viss spridning i numeriska resultat. En sammanställning av en generell bottom-up kostnadsmodell med detaljerad steg för steg-beskrivning för att genomföra en bottom-up kostnadsanalys är dessutom föreslagen i detta arbete.
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Karlsson, Axel. "Framtagning av beräkningsmall för rullaxlar." Thesis, Högskolan Väst, Avdelningen för maskinteknik och naturvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-7973.
Повний текст джерелаАнотація:
Möjligheter att förbättra Hofpartner ABs beräkningsmall för rullaxlar har undersökts. Undersökningen har fokuserat på användarvänlighet, ekonomi samt hållfasthet. Målet var att göra mallen mer lättanvänd. Nuvarande mall undersöks med resultat att den är väldigt svår att följa samt att dess värden inte överensstämmer särskilt bra med verkligheten i de flesta avseenden. Arbetet koncentreras därmed på att identifiera de existerande problemen och att åtgärda dem. Mallens funktioner utvärderas och beslut fattas om att reducera mallen till att endast hantera information som regelbundet används av företaget. Genom att minska mängden data ses möjligheter att göra mallen enklare att följa och mer lättanvänd med mindre krav på förkunskaper. Nya formler för hållfasthetsberäkningar framställs och implementeras i en nyskapad mall. Formlerna kontrolleras med analyser i FEM. Analyserna visar att de nya beräkningarna ger resultat närmare verkligheten. Kostnadsberäkningarna har konstruerats som en grund till Hofpartner att bygga vidare på. Formler är implementerade men en undersökning av företagets produktion krävs för att uppnå korrekta resultat. Undersökningen behöver utföras för att kartlägga tidsåtgång för företagets produktion, arbetet har endast lett till uppskattningar. Om undersökningen utförs har Hofpartner möjlighet att åstadkomma mycket rimliga resultat i mallen.In this project the possibilities to improve Hofpartner AB's calculation model for reel shafts has been investigated. The investigation has focused on user friendliness, economy and strength calculations. The goal was to make the model easier to use. An investigation of the current model shows that it is difficult to follow the calculations and that the results in most cases are not particularly accurate. Thus the work is focused on identifying the existing problems and improving on them. Several of the functions in the model are removed and the model now only handles information that are used with some regularity. By reducing the amount of data covered by the model possibilities is seen to simplify usage and to reduce the amount of necessary prior knowledge. New formulas for the strength calculations are presented and implemented in a new model. The formulas are verified by analysis with FEM. The analysis shows that the model is providing results close to the real values. The economical calculations are constructed as a basis for Hofpartner to continue developing. The necessary formulas are implemented but an investigation of the company's production process is necessary to achieve correct results. The newly constructed model mostly contains estimates of costs related to production time and material. If these estimates are updated with correct values Hofpartner has the possibility to achieve very reasonable results in their model.
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Simonazzi, Mattia. "Misalignment tolerant model and force calculation in a resonator array for inductive power transfer." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18981/.
Повний текст джерелаАнотація:
In this work, an inductive power transfer (IPT) system composed of an array of multiple magnetically coupled resonant inductors (cells) has been considered, allowing the transmission distance to be increased or the misalignment between the emitter and receiver coils to be considered. The analysis of the arrays can be carried out with the theory of magnetoinductive waves (MIW) or with circuit theory; the latter approach has been followed. The impedance matrix of the resonator array has been modelled for different receiver shapes and dimensions. Moreover, it has been expressed as a function of the space improving the accuracy of the model. The model has been exploited to calculate all the currents and voltages of the system. In first approximation, only the displacement in the MIW propagation direction has been considered, whereas the contribution of the receiver is expressed as a defect and becomes a function of the space as the mutual inductances between the circuits vary according to the receiver position. The self- and mutual inductance coefficients have been evaluated for each circuit of the system by applying the partial inductance method, whose formulas have been implemented in Matlab environment. These results have been validated by means of magnetostatic FEM analysis of the system using a commercial software. Experimental measurements on a prototype of a 1-D resonator array have been performed, confirming the calculated values of the currents and as a consequence, of the mutual inductances. The last part of the thesis is devoted to the calculation of the mechanical forces of electromagnetic origin experienced by the receiver over the array, as a result of the interaction between the whole magnetic field - generated by all the array cells - and the current circulating in the receiver. These forces have been theoretically discussed first, with a subsequent implementation of the calculation in Matlab environment and analysis of the obtained results.
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Mason, Colin Raymond. "An evaluation of model potential and pseudopotential methods for the calculation of interatomic potentials." Thesis, University College London (University of London), 1991. http://discovery.ucl.ac.uk/1363642/.
Повний текст джерелаАнотація:
This thesis presents an evaluation of the model potential and pseudopotential methods for the calculation of atom-atom interaction curves. At University College London, Peach has computed interatomic potential curves for several alkali-rare gas pairs using both the model potential and pseudopotential methods in a completely self-consistent manner. The value of these calculations is that any differences between the interatomic potential curves obtained from the model potential and pseudopotential methods can be attributed unambiguously to the theoretical representations of the Pauli exclusion principle which differentiate the two methods. The work of Peach thus allows the utility of these two representations to be compared directly and their effect on the quality of the resulting interatomic potentials to be assessed. The present study has developed a suite of computer programs designed to calculate observable quantities which are sensitive to the interatomic potentials. Calculations of the profiles, widths and shifts of the alkali resonance line when perturbed by rare gases, together with cross sections for fine structure state changing transitions within the alkali excited state multiplet, are reported and comparisons are made with experimental measurements of these observables. It is demonstrated that the theoretical representation of the Pauli exclusion principle has a significant effect on the quality of the resulting interatomic potentials. Observables calculated on the basis of interatomic potentials obtained via the model potential method are in better agreement with the available experimental data than those calculated on the basis of pseudopotential interaction curves. From this it may be inferred that the interatomic potentials obtained by the model potential method represent the actual interaction between alkali and rare gas atoms more accurately than do interatomic potentials obtained by the pseudopotential method. The results of this study provide strong evidence for the superiority of the model potential method for the calculation of interatomic potentials.
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馮德操 and Russell Fung. "Trajectory calculation in an electrostatic positron beam using a reformulated extended charge density model." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B31220836.
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Müller-Wohlfeil, Dirk-Ingemar. "Model frameworks for the calculation of annual runoff and nitrogen emissions from danish catchments." København : Ministry of Environment and Energy, National Environmental Research Institute, 2002. http://www.dmu.dk/1_viden/2_Publikationer/3_ovrige/rapporter/FR_PHD_DMW_01-46.pdf.
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Fung, Russell. "Trajectory calculation in an electrostatic positron beam using a reformulated extended charge density model /." Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B20567017.
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Ostatnicky, Tomas. "Model calculation of four-wave mixing polarization and dynamics in bulk and confined semiconductors." Université Louis Pasteur (Strasbourg) (1971-2008), 2005. https://publication-theses.unistra.fr/public/theses_doctorat/2005/OSTATNICKY_Tomas_2005.pdf.
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Pettersson, Anna, and Staffan Carolina Puga. "A Comparison between the Wickström Compartment Fire Model with Experiments and other Calculation Methods." Thesis, Luleå tekniska universitet, Byggkonstruktion och brand, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-87262.
Повний текст джерелаАнотація:
An Excel spreadsheet application has been developed for calculating pre-flashover compartment fire temperature according to the method described in the book ”Temperature Calculation in Fire Safety Engineering” written by Wickström 2016. Here called the Wickström Compartment Fire Model, WCFM, which is a model where the surrounding structure can be assumed either as lumped heat or as semi-infinite.The excel spreadsheet is user friendly and time efficient. The model has been used to calculate temperature of gas layer which is compared with results from experiments and calculations made with the alternative calculation methods MQH, FDS and CFAST. The compartment fire chosen for comparisons were performed in a normal sized room with a door opening. The walls, floor and ceiling of the room consisted of the same material but changed between the tests. Four materials were used: light weight concrete, uninsulated steel and insulated steel on inside or outside. The results of the comparison show that the temperature calculated with WCFM follows both the experiments and FDS temperature curves well for three of the tests. The test with light weight concrete differs from the results where WCFM in the end stabilises at a lower temperature. The difference that occurred between WCFM, the experiments and FDS, for the other three tests is mainly in the beginning of the tests. WCFM predicts temperatures which are as an average 100 ℃ higher or lower than what measured depending on test setup. In the end of the test WCFM, the experiments and FDS coincide and give essentially the same final temperatures. The temperature from MQH and CFAST differ considerably from the experiments in all the tests.
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Wang, Qi. "Multiscale Modeling of Mechanisms of Substrate Protein Translocation and Degradation Product Release by the Bacterial ClpP Peptidase." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1581333440993555.
Повний текст джерела
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Hnatenko, O. S., and V. P. Obozna. "Calculation of the Stability of the Fiber Ring Laser with Liquid Crystal Polarization Controllers." Thesis, Sumy State University, 2018. http://openarchive.nure.ua/handle/document/6802.
Повний текст джерелаАнотація:
To date, with the ultra-short pulse lasers are used in many areas of science and technology, including information technology. The main task of creating such lasers is to provide output radiation with the shortest pulse duration. The shortest duration pulses achieved in fiber ring lasers with nonlinear rotating polarization modes, namely 20 fs. But in such lasers, there are a number of problems: stability of operation and tuning of the mode locking. This is due to the tuning of the mode-locked by rotating the wave plates in space manually.
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Hnatenko, О. S., and V. P. Obozna. "Calculation of the Stability of the Fiber Ring Laser with Liquid Crystal Polarization Controllers." Thesis, Sumy State University, 2018. http://essuir.sumdu.edu.ua/handle/123456789/67950.
Повний текст джерелаАнотація:
To date, with the ultra-short pulse lasers are used in many areas of science and technology, including information technology. The main task of creating such lasers is to provide output radiation with the shortest pulse duration. The shortest duration pulses achieved in fiber ring lasers with nonlinear rotating polarization modes, namely 20 fs. But in such lasers, there are a number of problems: stability of operation and tuning of the mode locking. This is due to the tuning of the mode-locked by rotating the wave plates in space manually.
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Seppälä, Tiina. "FiR epithermal neutron beam model and dose calculation for treatment planning in neutron capture therapy." Helsinki : University of Helsinki, 2002. http://ethesis.helsinki.fi/julkaisut/mat/fysik/vk/seppala/.
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Lin, Ming-Shr Matt Wilson R. M. Wilson R. M. "Applications of combinatorial analysis to the calculation of the partition function of the Ising Model /." Diss., Pasadena, Calif. : California Institute of Technology, 2009. http://resolver.caltech.edu/CaltechETD:etd-05052009-133119.
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Munkejord, Svend Tollak. "Analysis of the two-fluid model and the drift-flux model for numerical calculation of two-phase flow." Doctoral thesis, Norwegian University of Science and Technology, Faculty of Engineering Science and Technology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-679.
Повний текст джерелаАнотація:
Flerfasestrømning er av betydning i en lang rekke anvendelser, blant annet i olje- og gassindustrien, i den kjemiske og i prosessindustrien, inkludert i varmepumpende systemer, samt i sikkerhetsanalyse av kjernekraftverk. Denne avhandlingen analyserer modeller for tofasestrømning, og metoder for numerisk løsning av disse modellene. Den er derfor ett bidrag til å utvikle pålitelige ingeniørverktøy for flerfase-anvendelser. Slike verktøy trengs og forventes av ingeniører i industrien.
Den tilnærmede Riemann-løseren framsatt av Roe har blitt studert. Roe-skjema for tre ulike modeller for tofasestrømning har blitt implementert i rammen av en standard numerisk algoritme for løsning av hyperbolske bevaringslover. Disse skjemaene har blitt analysert ved hjelp av referanse-regnestykker fra litteraturen, og ved sammenlikning med hverandre.
Et Roe-skjema for den fire-liknings ettrykks tofluid-modellen har blitt implementert, og det har blitt vist at en andreordens utvidelse basert på bølge-dekomponering og fluksdifferanse-splitting virker godt, og gir forbedrede resultater sammenliknet med det førsteordens skjemaet.
Det har blitt foreslått et Roe-skjema for en fem-liknings totrykks tofluid-modell med trykkrelaksering. Bruken av analoge numeriske metoder for fire-liknings- og fem-liknings-modellene gjorde det mulig med en direkte sammenlikning av en metode med og uten trykkrelaksering. Numeriske eksperiment demonstrerte at de to framgangsmåtene konvergerte til samme resultat, men at den fem-liknings trykkrelakserings-metoden var betydelig mer dissipativ, særlig for kontakt-diskontinuiteter. Videre viste beregninger at selv om fem-liknings-modellen har reelle egenverdier, så produserte den oscillasjoner for tilfeller der fire-liknings-modellen hadde komplekse egenverdier.
Et Roe-skjema har blitt konstruert for driftfluks-modellen med generelle lukningslover. Roe-matrisen er helt analytisk for det tilfellet at man kan anvende Zuber-Findlay-slipp-loven som beskriver boblestrømning. Dermed er dette Roe-skjemaet mer effektivt enn tidligere fullt numeriske Roe-skjema for driftfluks-modellen.
En isentropisk diskret-nivå-flerfasemodell har blitt presentert. En diskusjon av hvordan man kan ta hensyn til ulike interfase-trykkmodeller har blitt gitt. Med de passende modellene for interfase-trykk og -fart, var samsvaret svært godt mellom diskret-nivå-modellen og det fem-liknings Roe-skjemaet.
Multi-steg- (MUSTA) metoden har som siktemål å komme nær oppstrøms-metodene i nøyaktighet, samtidig som den bevarer enkelheten til sentrerte skjema. Her har metoden blitt brukt på driftfluks-modellen. Når antallet steg økes, nærmer resultatene fra MUSTA-metoden seg det man får med Roe-metoden. De gode resultatene til MUSTA-metoden er avhengige av at man bruker et stort nok lokalt grid. Derfor er hovedfordelen med MUSTA-metoden at den er enkel, snarere enn at man sparer regnetid.
En karakteristikk-basert metode for å spesifisere grensebetinglser for flerfase-modeller har blitt testet, og funnet å virke godt for transiente problem.
This thesis analyses models for two-phase flows and methods for the numerical resolution of these models. It is therefore one contribution to the development of reliable design tools for multiphase applications. Such tools are needed and expected by engineers in a range of fields, including in the oil and gas industry.
The approximate Riemann solver of Roe has been studied. Roe schemes for three different two-phase flow models have been implemented in the framework of a standard numerical algorithm for the solution of hyperbolic conservation laws. The schemes have been analysed by calculation of benchmark tests from the literature, and by comparison with each other.
A Roe scheme for the four-equation one-pressure two-fluid model has been implemented, and a second-order extension based on wave decomposition and flux-difference splitting was shown to work well and to give improved results compared to the first-order scheme. The convergence properties of the scheme were tested on smooth and discontinuous solutions.
A Roe scheme has been proposed for a five-equation two-pressure two-fluid model with pressure relaxation. The use of analogous numerical methods for the five-equation and four-equation models allowed for a direct comparison of a method with and without pressure relaxation. Numerical experiments demonstrated that the two approaches converged to the same results, but that the five-equation pressure-relaxation method was significantly more dissipative, particularly for contact discontinuities. Furthermore, even though the five-equation model with instantaneous pressure relaxation has real eigenvalues, the calculations showed that it produced oscillations for cases where the four-equation model had complex eigenvalues.
A Roe scheme has been constructed for the drift-flux model with general closure laws. For the case of the Zuber-Findlay slip law describing bubbly flows, the Roe matrix is completely analytical. Hence the present Roe scheme is more efficient than previous fully numerical Roe schemes for the drift-flux model.
An isentropic discrete-equation multiphase model has been presented. The incorporation of different interfacial-pressure models was discussed, and examples were given. With the adequate models for the interfacial pressure and velocity, the agreement was very good between the discrete-equation model and the five-equation Roe scheme.
The flux-limiter centred (FLIC) scheme was tested for the four-equation two-fluid model. Only the first-order version (FORCE) of the scheme was found to work well, but it was rather diffusive. The purpose of the multi-stage (MUSTA) method is to come close to the accuracy of upwind schemes while retaining the simplicity of centred schemes. Here it has been applied to the drift-flux model. As the number of stages was increased, the results of the MUSTA scheme approached those of the Roe method. The good results of the MUSTA scheme were dependent on the use of a large-enough local grid. Hence, the main advantage of the MUSTA scheme is its simplicity.
A multiphase characteristic-based boundary-condition method has been tested, and it was shown to be workable for transient problems.
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Heidari, Shayan. "Economic Modelling of Floating Offshore Wind Power : Calculation of Levelized Cost of Energy." Thesis, Mälardalens högskola, Industriell ekonomi och organisation, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-36130.
Повний текст джерелаАнотація:
Floating offshore wind power is a relatively new technology that enables wind turbines to float above the sea level, tied by anchors at the seabed. The purpose of this work is to develop an economic model for the technology in order to calculate the total cost of a planned wind farm. Cost data are retrieved from reports and academic journals available online. Based on these data, a model in Microsoft Excel is developed which calculates the Levelized cost of energy (LCOE) for floating wind power plants as a function of several input values. As an addition to this model, financing offshore projects are described using literature study and by doing interviews with three major companies, currently investing in offshore wind. As a result, the model allows the user to calculate Capital expenditures, Operating expenditures and LCOE for projects at any given size and at any given site. The current LCOE for a large floating offshore wind farm is indicated to be in the range of 138-147 £/MWh. The outline from interviews was that today there is no shortage of capital for funding wind projects. However, in order to attract capital, the governmental regulatory of that market has to be suitable since it has a crucial impact on price risks of a project.
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Cheng, Xi. "Quantification of the parametric uncertainty in the specific absorption rate calculation of a mobile phone." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS258/document.
Повний текст джерелаАнотація:
La thèse porte sur la quantification d'incertitude de paramètres (Uncertainty Quantification ou UQ) dans le calcul du débit d'absorption spécifique (Specific Absorption Rate ou SAR) de téléphones mobiles. L'impact de l'incertitude, ainsi le manque de connaissances détaillées sur les propriétés électriques des matériaux, les caractéristiques géométriques du système, etc., dans le calcul SAR est quantifiée par trois méthodes de calcul efficaces dites non-intrusives : Transformation non parfumée (Unscented Transformation ou UT), collocation stochastique (Stochastic Collocation ou SC) et polynômes de chaos non-intrusifs (Non-Intrusive Polynomial Chaos ou NIPC).Ces méthodes sont en effet appelées méthodes non intrusives puisque le processus de simulation est tout simplement considéré comme une boîte noire sans que ne soit modifié le code du solveur de simulation. Leurs performances pour les cas de une et deux variables aléatoires sont analysées dans le présent travail. En contraste avec le procédé d'analyse d'incertitude traditionnel (la méthode de Monte Carlo ou MCM), le temps de calcul devient acceptable. Afin de simplifier la procédure UQ pour le cas de plusieurs entrées incertaines, il est démontré que des incertitudes peuvent être combinées de manière à évaluer l'incertitude sur les paramètres de la sortie.Combiner des incertitudes est une approche généralement utilisée dans le domaine des mesures, et ici, il est utilisé dans le calcul du SAR pour la situation complexe. Une des étapes nécessaires dans le cadre de l'analyse d'incertitude est l'analyse de sensibilité (Sensitivity Analysis ou SA), qui vise à quantifier l'importance relative de chaque paramètre d'entrée incertain par rapport à l'incertitude de la sortie. La méthode reposant sur le calcul des indices de sensibilité de Sobol est employée, ces indices étant évalués par un développement en polynômes de chaos, au lieu d'utiliser la méthode de Monte-Carlo dans le calcul SAR. Les résultats des investigations sont présentés et discutés.Afin de faciliter la lecture, des notions élémentaires de débit d'absorption spécifique, de modélisation, d'incertitude dans la modélisation, de théorie des probabilités, et de calcul SAR par l'un des solveurs de simulation sont proposés dans l'Introduction (chapitre 1). Puis l'usage des méthodes non-intrusives UQ telles que UT, SC et NIPC, et l'application de la méthode des indices de Sobol pour l'analyse de sensibilité dans le calcul SAR est présentée dans les chapitres 2 et 3. Dans le chapitre 4, une autre approche d'utilisation des polynômes de chaos est fournie, et elle est utilisée dans le domaine temporel par l'intermédiaire d'un code de différences finies (Finite Difference-Time Domain ou FD-TD). Puisque le code FD-TD dans le solveur de simulation peut en effet être modifié, c'est le développement en polynômes de chaos intrusifs, étudié en détail par un certain nombre de scientifiques déjà, qui est considéré. Dans le chapitre 5, les conclusions et un aperçu des travaux futurs sont fournisThis thesis focuses on parameter uncertainty quantification (UQ) in specific absorptionrate (SAR) calculation using a computer-aided design (CAD) mobile phone model.The impact of uncertainty, e.g., lack of detailed knowledge about material electricalproperties, system geometrical features, etc., in SAR calculation is quantified by threecomputationally efficient non-intrusive UQ methods: unscented transformation (UT),stochastic collocation (SC) and non-intrusive polynomial chaos (NIPC). They are callednon-intrusive methods because the simulation process is simply considered as a blackboxwithout changing the code of the simulation solver. Their performances for thecases of one and two random variables are analysed. In contrast to the traditionaluncertainty analysis method: Monte Carlo method, the time of the calculation becomesacceptable. To simplify the UQ procedure for the case of multiple uncertain inputs, it isdemonstrated that uncertainties can be combined to evaluate the parameter uncertaintyof the output. Combining uncertainties is an approach generally used in the field ofmeasurement, in this thesis, it is used in SAR calculations in the complex situation. Oneof the necessary steps in the framework of uncertainty analysis is sensitivity analysis (SA)which aims at quantifying the relative importance of each uncertain input parameterwith respect to the uncertainty of the output. Polynomial chaos (PC) based Sobol’indices method whose SA indices are evaluated by PC expansion instead of Monte Carlomethod is used in SAR calculation. The results of the investigations are presented anddiscussed.In order to make the reading easier, elementary notions of SAR, modelling, uncertaintyin modelling, and probability theory are given in introduction (chapter 1). Thenthe main content of this thesis are presented in chapter 2 and chapter 3. In chapter 4,another approach to use PC expansion is given, and it is used in the finite-differencetime-domain (FDTD) code. Since the FDTD code in the simulation solver should bechanged, it is so-called intrusive PC expansion. Intrusive method already investigatedin details in other people’s thesis. In chapter 5, conclusions and future work are given
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Lee, Michelle Oi San. "Sample size calculation for testing an interaction effect in a logistic regression under measurement error model /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?MATH%202003%20LEE.
Повний текст джерелаАнотація:
Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003.Includes bibliographical references (leaves 66-67). Also available in electronic version. Access restricted to campus users.
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Nguyen, Thi Van Anh, Xuan Hien Dang, and Duc Toan Nguyen. "Research on model-based calculation of greenhouse gas emissions from domestic wastewater treatment systems in Vietnam." Technische Universität Dresden, 2016. https://tud.qucosa.de/id/qucosa%3A32621.
Повний текст джерелаАнотація:
There are three important greenhouse gases: carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), which are generated from the domestic wastewater treatment systems, including on-site and off-site sources. On-site emission of greenhouse gases occurs during process of wastewater treatment, while the off-site emission of greenhouse gases occurs during energy using and other supporting activities of the treatment system. The research established model to calculate greenhouse gas emissions from the domestic wastewater treatment systems, was named No.0 MTH model. The No.0 MTH model was based on balance equations of substrate and biomass, biochemical reactions and Monod kinetics equations for biological treatment reactors and writen by programing Scalable language. Model was calibrated and applied on the Yen So wastewater treatment plant, Ha Noi and the results were obtained at 22oC as follows: off-site GHG emission is 29,560 kgCO2-eq/day; on-site GHG emission is 13,534 kgCO2-eq/day, and the rate of on-site emission is 2.506 kgCO2-eq/ kg BOD. Maybe using the No.0 MTH model to calculate greenhouse gas emissions from the domestic wastewater treatment systems with similar biological methods.Có 3 khí nhà kính quan trọng là khí Cacbonic (CO2), khí Mêtan (CH4), và khí Đinitơ monoxit (N2O) được phát sinh từ hệ thống xử lý nước thải sinh hoạt gồm cả nguồn trực tiếp và gián tiếp. Phát thải trực tiếp khí nhà kính (KHK) xảy ra trong suốt quá trình xử lý còn phát thải gián tiếp khí nhà kính xảy ra trong quá trình sử dụng năng lượng và các hoạt động phụ trợ bên ngoài hệ thống xử lý. Nghiên cứu đã thiết lập mô hình tính toán phát thải khí nhà kính từ hệ thống xử lý nước thải sinh hoạt, được đặt tên là mô hình MTH số 0. Mô hình MTH số 0 đã dựa trên các phương trình cân bằng khối lượng cơ chất và sinh khối, các phản ứng hóa sinh và phương trình Monod đối với các thiết bị xử lý sinh học và được viết trên ngôn ngữ lập trình scala. Mô hình đã được hiệu chỉnh và được áp dụng tính toán tại nhà máy xử lý nước thải sinh hoạt Yên Sở, thành phố Hà Nội và kết quả thu được tại 22oC như sau: phát thải KNK gián tiếp là 29.560 kgCO2-tđ/ngày và phát thải KNK trực tiếp là 13.534 kgCO2-tđ/ngày với tỷ lệ phát thải khí nhà kính trực tiếp là 2,506 kgCO2-tđ/ kgBOD. Có thể sử dụng mô hình MTH số 0 để tính toán phát thải khí nhà kính từ hệ thống xử lý nước thải sinh hoạt bằng phương pháp sinh học tương tự.
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Chappell, Isaac Samuel 1972. "Calculation of interface tension and stiffness in a two dimensional Ising Model by Monte Carlo simulation." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/49672.
Повний текст джерелаАнотація:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Physics, 1998.Includes bibliographical references (p. 55).
The two dimensional Ising Model is important because it describes various condensed matter systems. At low temperatures, spontaneous symmetry breaking occurs such that two coexisting phases are separated by interfaces. These interfaces can be described as vibrating strings and are characterized by their tension and stiffness. Then the partition function can be calculated as a function of the magnetization with the interface tension and stiffness as parameters. Simulating the two dimensional Ising Model on square lattices of various sizes, the partition function is determined in order to extract the interface tension. The configurations being studied have low probability of actual occurrence and would require a large number of Monte Carlo steps before obtaining a good sampling. By using improved estimators and a trial distribution, fewer steps are needed. Improved estimators decrease the number of steps to achieve a certain level of accuracy. The trial distribution allows increased statistics once the general shape of the probability distribution is calculated from a Monte Carlo simulation. For small lattice sizes, it is easy to run Monte Carlo simulations to generate the trial distribution. At larger lattice sizes, it is necessary to build the trial distribution from a combination of a Monte Carlo simulation and an Ansatz from theory due to lower statistics. The extracted values of the interface tension agree with the analytical solution by Onsager.
by Isaac Samuel Chappell, II.
S.M.
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Galvin, Geordie. "Comparison of on-pond measurement and back calculation of odour emission rates from anaerobic piggery lagoons." University of Southern Queensland, Faculty of Engineering and Surveying, 2005. http://eprints.usq.edu.au/archive/00001426/.
Повний текст джерелаАнотація:
Odours are emitted from numerous sources and can form a natural part of the environment. The sources of odour range from natural to industrial sources and can be perceived by the community dependant upon a number of factors. These factors include frequency, intensity, duration, offensiveness and location (FIDOL). Or in other words how strong an odour is, at what level it becomes detectable, how long it can be smelt for, whether or not the odour is an acceptable or unacceptable smell as judged by the receptor (residents) and where the odour is smelt. Intensive livestock operations cover a wide range of animal production enterprises, with all of these emitting odours. Essentially, intensive livestock in Queensland, and a certain extent Australia, refers to piggeries, feedlots and intensive dairy and poultry operations. Odour emissions from these operations can be a significant concern when the distance to nearby residents is small enough that odour from the operations is detected. The distance to receptors is a concern for intensive livestock operations as it may hamper their ability to develop new sites or expand existing sites. The piggery industry in Australia relies upon anaerobic treatment to treat its liquid wastes. These earthen lagoons treat liquid wastes through degradation via biological activity (Barth 1985; Casey and McGahan 2000). As these lagoons emit up to 80 per cent of the odour from a piggery (Smith et al., 1999), it is imperative for the piggery industry that odour be better quantified. Numerous methods have been adopted throughout the world for the measurement of odour including, trained field sniffers, electronic noses, olfactometry and electronic methods such as gas chromatography. Although these methods all have can be used, olfactometry is currently deemed to be the most appropriate method for accurate and repeatable determination of odour. This is due to the standardisation of olfactometry through the Australian / New Zealand Standard for Dynamic Olfactometry and that olfactometry uses a standardised panel of "sniffers" which tend to give a repeatable indication of odour concentration. This is important as often, electronic measures cannot relate odour back to the human nose, which is the ultimate assessor of odour. The way in which odour emission rates (OERs) from lagoons are determined is subject to debate. Currently the most commonly used methods are direct and indirect methods. Direct methods refer to placing enclosures on the ponds to measure the emissions whereas indirect methods refer to taking downwind samples on or near a pond and calculating an emission rate. Worldwide the odour community is currently divided into two camps that disagree on how to directly measure odour, those who use the UNSW wind tunnel or similar (Jiang et al., 1995; Byler et al., 2004; Hudson and Casey 2002; Heber et al., 2000; Schmidt and Bicudo 2002; Bliss et al., 1995) or the USEPA flux chamber (Gholson et al., 1989; Heber et al., 2000; Feddes et al., 2001; Witherspoon et al., 2002; Schmidt and Bicudo 2002; Gholson et al., 1991; Kienbusch 1986). The majority of peer reviewed literature shows that static chambers such as the USEPA flux chamber under predict emissions (Gao et al., 1998b; Jiang and Kaye 1996) and based on this, the literature recommends wind tunnel type devices as the most appropriate method of determining emissions (Smith and Watts 1994a; Jiang and Kaye 1996; Gao et al., 1998a). Based on these reviews it was decided to compare the indirect STINK model (Smith 1995) with the UNSW wind tunnel to assess the appropriateness of the methods for determining odour emission rates for area sources. The objective of this project was to assess the suitability of the STINK model and UNSW wind tunnel for determining odour emission rates from anaerobic piggery lagoons. In particular determining if the model compared well with UNSW wind tunnel measurements from the same source; the overall efficacy of the model; and the relationship between source footprint and predicted odour emission rate.
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Aikio, Englund Rebecca. "A study of calculation models for fatigue life prediction : A thesis accomplished together with GKN Aerospace." Thesis, Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-67741.
Повний текст джерелаАнотація:
GKN Aerospace in Trollhättan don’t use the latest ANSYS version and need to upgrade their life analysis models. The aim with this thesis is to do a study of the new models and investigate the times required for the calculations. A flight mission were chosen and this mission together with different life analysis models were run in the GKN in house program Life Analysis System. The results were analyzed and depending on the results additional runs were made or the problem were sent to the life management group at GKN Aerospace. Strain levels versus time were also plotted for the runs with the new models to get a perception where any problems occurs. The results from the model 4.10.149 had no variations between equal runs for the high pressure turbine and the low pressure turbine but there was a variation between the results when equal runs was made with the high pressure compressor. The results from model 4.10.157 and 4.10.124 and 4.10.160 and 4.10.173 had variations in the fatigue life for equal runs. The variations can depend on that the calculations converges to different solutions, the reason for this can depend on the non-linear contact elements. The variation in the results between equal runs occurs when the model uses two or more cores. The time required for the calculation becomes faster with the use of more cores. The longest duration had model 4.10.173 because of the many requirements for the calculations in this model. The problem with the variation in the results is sent to ANSYS.
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Park, Borinara. "Development of a Virtual Reality Excavator Simulator: a Mathematical Model of Excavator Digging and a Calculation Methodology." Diss., Virginia Tech, 2002. http://hdl.handle.net/10919/29801.
Повний текст джерелаАнотація:
Virtual Reality (VR) simulators have become popular because of two distinctive merits. One is the capability to transfer data and information to users in an intuitive way by means of 3-D high-quality graphics output and real input devices. The other is the capability to represent physical systems in mathematical models so that meaningful responses of the systems can be predicted. Previous efforts in VR excavating machine simulator development, however, showed a lack of balance between the fidelity of the model of the physics and the visual representation of the simulated equipment.
In order to ensure that a VR construction excavator simulator provides convincing operating results to users, the focus of simulator development needs to be shifted to interaction of physically valid soil and the excavator machine.
This research aims to contribute to the development of a VR construction excavator simulator system by proposing a mathematical model of excavator digging and a calculation methodology. The mathematical model of excavator digging provides physically meaningful soil-bucket interaction information to a simulator. The calculation methodology provides systematic and efficient computation methods to ensure the seamless integration of the excavator digging model with a VR simulator system as well as adequate system speed. As a result, the simulator is realized as an engineering process tool equipped with real-time interactivity.Ph. D.
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Humpherys, Candice Marie. "Application of an Isogeometric Boundary Element Method to the Calculation of Acoustic Radiation Modes and Their Efficiencies." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/4371.
Повний текст джерелаАнотація:
In contrast to the structural modes, which describe the physical motion of vibrating structures, acoustic radiation modes describe the radiated sound power. Radiation modes are beneficial in active noise control because reducing an efficiently radiating radiation mode guarantees the reduction of radiated sound power. Much work has been done to calculate the radiation modes for simple geometries, where analytic solutions are available. In this work, isogeometric analysis (IGA) is used to provide a tool capable of analyzing the radiation modes of arbitrarily complex geometries. IGA offers increased accuracy and efficiency by using basis functions generated from Non-Uniform Rational B-Splines (NURBS) or T-Splines, which can represent geometries exactly. Results showing this increased accuracy and efficiency with IGA using T-Splines are shown for a sphere to validate the method, comparing with the exact analytical solution as well as results from a traditional boundary element method. A free cylindrical shell is also analyzed to show the usefulness of this method. Expected similarities, as well as expected differences, are observed between this free shell and a baffled cylindrical shell.
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Rane, Lukas, and Henrik Runeskog. "Calculating Center of Mass Using List Mode Data from PET Biograph128 mCT-1104." Thesis, KTH, Medicinteknik och hälsosystem, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-256084.
Повний текст джерелаАнотація:
A common problem within positron emission tomography examinations of the brain is the motion of the patient. If the patients ́ head moves during an examination all the data acquired after the movement will not be suited for clinical use. This means that a lot of data recovered from PET is not used at all. Motion tracking during PET acquisitions of the brain is not a well explored issue within medical imaging in relation to the magnitude of the problem. Due to the radiation risks of the examination and the logistics at the hospital, a second acquisition is not preferred. Therefore a method to avoid a second acquisition would be welcome. PET data saved in list mode makes it possible to analyze the data during an examination. By calculating the center of mass of the object examined in list mode only using the raw data from PET and use it as a tracking point, it would be possible to track a motion during an acquisition. The center of mass could therefore possibly be used as a reference to connect two different time intervals on each side of the moment were the motion occurred. The raw PET data used for this project was acquired in the Nuclear Medicine Department in Karolinska University Hospital in Huddinge and covered four turns of one minute acquisitions in different positions and with two different objects that were saved in list mode. The acquisitions were analyzed with the Siemens software e7-tools and sliced into time intervals. To calculate the center of mass within these time intervals, two methods were developed. One method only used the Siemens software e7-tools and histogrammed the time of flight bin position. The other method used each event position in its sinogram to calculate a center of mass sinusoidal equation. This equation lead to coordinates describing the center of mass in a specific slice.Ett vanligt problem inom positronemissiontomografiundersökningar av hjärnan är rörelser från patienten. Om patienten rör sitt huvud under undersökningen kommer all förvärvad data inte vara kliniskt lämpad. Detta innebär att en stor del av datan från en PET-undersökning inte används över huvud taget. Rörelsespårning under PET undersökningar av hjärnan är ett relativt outforskat ämne inom medicinsk bildgivning i relation till amplituden av problemet. På grund av strålningsrisken av un- dersökningen och logistiken på sjukhusen, är en andra bildtagning inte att föredra. Därför skulle en metod för att undvika en andra bildtagning vara uppskattad. PET-rådata sparad i list mode möjliggör analys av data inom tidsspektrat av en undersökning. Genom att beräkna det undersökta objektets barocentrum genom att enbart använda rådata sparad i list mode och använda detta som en referenspunkt, så finns en möjlighet att följa en rörelse under en undersökning. Objektets barocentrum skulle kunna fungera som en referenspunkt för att binda ihop två olika tidsegment på varsin sida om tillfället då en rörelse har skett. Rådatan som användes i detta projekt var förvärvad vid nukleärmedicinska avdelningen på Karolinska Universetetssjukhuset i Huddinge och täckte fyra stycken undersökningar på en minut vardera i olika positioner och två olika objekt som sparades i list mode. Datainsamlingarna över- sattes med Siemens-mjukvaran e7-tools och delades sedan upp i tidsegment. För att räkna ut ett barocentrum i dessa tidssegment så utvecklades två metoder. En metod använde sig enbart av Siemens-mjukvaran e7-tools och använde dess funktion ”histogramming” för att dela upp alla events time of flight position. Den andra metoden använde varje events position i dess sinogram för att beräkna en barocentrisk sinusformad funktion. Denna funktion ledde till koordinater som beskrev masscentrum i en specifik skiva.