Dissertations / Theses on the topic 'Calculation of the mode'
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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.
Full textRubio, 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.
Full textMohamed, 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.
Full textF.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
Wigmore, Ioan Tomos. "Automated calculation of one-loop processes within MadGolem." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/7967.
Full textWiegmann, 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/.
Full textFERREIRA, 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.
Full textThe 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.
Mujagic, Ubejd. "Strength Calculation Model for Standoff Screws in Composite Joists." Thesis, Virginia Tech, 2000. http://hdl.handle.net/10919/35960.
Full textMaster of Science
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.
Full textSubsea 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.
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.
Full textBerglund, 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.
Full textTegbrant, 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.
Full textEtt 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.
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.
Full textWolfe, 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.
Full textSkjelbred, 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.
Full textBirindelli, Gabriele. "Entropic model for dose calculation in external beam radiotherapy and brachytherapy." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0057.
Full textThis 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
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.
Full textLoughman, 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.
Full textHoshmeh, 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.
Full textWesslund, 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.
Full textThis 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.
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.
Full textPařízková, Iva. "Matematický model teplárenské sítě." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-241664.
Full textPykalová, 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.
Full textIsmayilov, 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.
Full textEscudero, 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.
Full textLa 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.
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.
Full textLi, 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.
Full textAtt 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.
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.
Full textIn 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.
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/.
Full textMason, 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/.
Full text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.
Full textMüller-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.
Full textFung, 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.
Full textOstatnicky, 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.
Full textPettersson, 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.
Full textWang, 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.
Full textHnatenko, 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.
Full textHnatenko, 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.
Full textSeppälä, 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/.
Full textLin, 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.
Full textMunkejord, 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.
Full textFlerfasestrømning 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.
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.
Full textCheng, 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.
Full textThis 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
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.
Full textIncludes bibliographical references (leaves 66-67). Also available in electronic version. Access restricted to campus users.
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.
Full textCó 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.
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.
Full textIncludes 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.
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/.
Full textAikio, 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.
Full textPark, 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.
Full textPh. D.
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.
Full textRane, 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.
Full textEtt 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.