Dissertations / Theses on the topic 'Semi-empirical'
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Keal, Thomas W. "Development of semi-empirical exchange-correlation functionals." Thesis, Durham University, 2005. http://etheses.dur.ac.uk/2870/.
Full textElder, Warren James. "Semi-empirical modelling of SiGe hetero-structures." Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/9816.
Full textUmsrithong, Anake. "Deterministic and Stochastic Semi-Empirical Transient Tire Models." Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/26270.
Full textPh. D.
Sirbone, Fabio Renato Camargo. "Modelagem semi-empírica de compressores herméticos alternativos." Universidade de São Paulo, 2007. http://www.teses.usp.br/teses/disponiveis/18/18147/tde-18072007-111535/.
Full textIn the present work is applied a semi-empirical method that uses a non-linear optimization technique for determination of the volumetric and combined efficiencies of hermetic reciprocating compressor. Relations to approximately estimate the mass flow and the electric power of the compressor are also proposed. All these compressor characteristics are calculated through physical model relations, used in the optimization calculations. The method is implemented in the EES (Engineering Equation Solver) software and is based on the works of Jahing (1999) and Jahing et al. (2000). In the method, four experimental measurements of the mass flow and electric power are enough to determine the fitting parameters of the model. This procedure allows the generation of satisfactory compressor maps without the necessity of a higher number of experimental data, as in the case of norm ARI 540 application. The results obtained with the model can be used for the design of new compressors.
Petersson, Emil. "Study of semi-empirical methods for ship resistance calculations." Thesis, Uppsala universitet, Tillämpad mekanik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-413700.
Full textAllison, Anne-Marie E. "Analytical investigation of a semi-empirical flow-induced vibration model." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape15/PQDD_0014/NQ31170.pdf.
Full textFord, D. C. "A semi-empirical model of the spectra of dusty galaxies." Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.599112.
Full textSaeed, Awat Abdulla. "Empirical evaluation of semi-supervised naïve Bayes for active learning." Thesis, University of East Anglia, 2018. https://ueaeprints.uea.ac.uk/67655/.
Full textFu, Jie. "Developing semi-empirical ab initio based potentials in materials modeling." Licentiate thesis, KTH, Kondenserade materiens teori, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-190125.
Full textQC 20160815
Razali, Rozilawati. "Usability of semi-formal and formal methods integration : empirical assessments." Thesis, University of Southampton, 2008. https://eprints.soton.ac.uk/265391/.
Full textBittermann, Klaus [Verfasser], and Stefan [Akademischer Betreuer] Rahmstorf. "Semi-empirical sea-level modelling / Klaus Bittermann ; Betreuer: Stefan Rahmstorf." Potsdam : Universität Potsdam, 2015. http://d-nb.info/1219149209/34.
Full textChopping, M. J. "Linear semi-empirical kernel-driven bidirectional reflectance distribution function models in monitoring semi-arid grasslands from space." Thesis, University of Nottingham, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262949.
Full textNami, Ziba. "Semi-empirical and numerical modeling of metal-organic chemical vapor deposition." Diss., Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/16418.
Full textAsiri, Yazeed. "Ab Initio and Semi-Empirical Calculations of Cyanoligated Rhodium Dimer Complexs." Digital Commons @ East Tennessee State University, 2017. https://dc.etsu.edu/etd/3177.
Full textLiu, Xiaoxia. "Semi-Empirical Likelihood Confidence Intervals for the ROC Curve with Missing Data." Digital Archive @ GSU, 2010. http://digitalarchive.gsu.edu/math_theses/89.
Full textZapata-Medina, David G. "SEMI-EMPIRICAL METHOD FOR DESIGNING EXCAVATION SUPPORT SYSTEMS BASED ON DEFORMATION CONTROL." UKnowledge, 2007. http://uknowledge.uky.edu/gradschool_theses/468.
Full textUgwu, Johnson Obunwa. "A semi-empirical approach to modelling well deliverability in gas condensate reservoirs." Thesis, Robert Gordon University, 2011. http://hdl.handle.net/10059/1115.
Full textGeisbert, Jesse Stuart. "Hydrodynamic Modeling for Autonomous Underwater Vehicles Using Computational and Semi-Empirical Methods." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/33195.
Full textMaster of Science
Fortuin, Adrian Charles. "Development of a semi–empirical reaction kinetic model for PEM fuel cells." Master's thesis, University of Cape Town, 2013. http://hdl.handle.net/11427/5334.
Full textGarba, Michael. "Adaptive heterogeneous parallelism for semi-empirical lattice dynamics in computational materials science." Thesis, Robert Gordon University, 2015. http://hdl.handle.net/10059/1237.
Full textLu, Ruihua. "Development of a semi-empirical ship operational performance model for voyage optimization." Thesis, University of Strathclyde, 2016. http://digitool.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=27486.
Full textRasoolzadeh, R. "Computational Study of Amino Acids, Order to Simulation of Membrane Protein Channels Using by Theoretical Methods." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35428.
Full textBretanha, Neto Nelson [UNESP]. "Métodos Semi-Empíricos: princípios básicos e aplicações." Universidade Estadual Paulista (UNESP), 2015. http://hdl.handle.net/11449/132417.
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Neste trabalho investigamos os efeitos decorrentes da presença de heteroátomos numa folha de “supercoroneno” (molécula C58H18 utilizada como uma primeira aproximação para o grafeno). Mais especificamente, utilizando método semi-empírico PM6, implementado no pacote computacional MOPAC2012®, estudamos as diferentes curvas de energia (calor de formação). As curvas estudadas foram obtidas pela passagem de um átomo de carbono sobre uma folha de supercoroneno na qual existe um heteroátomo (foram utilizadas três diferentes estruturas: C57H18Si, C57H18Ge e C57H18Sn). Nesse contexto, estudamos também o efeito destes heteroátomos sobre a densidade eletrônica e os orbitais HOMO e LUMO das diferentes estruturas.
In this work we investigate the effects of the presence of heteroatoms on a “supercoronene” sheet (C58H18 molecule used as a molecular model for graphene). Specifically, we used the semiempirical method PM6 as implemented in MOPAC2012® software to study several (formation) energy curves. The energy curves were obtained by positioning a carbon atom over a “supercoronene” sheet in which there is a heteroatom (this was done for three different structures: C57H18Si, C57H18Ge and C57H18Sn). In this context, the effect of these heteroatoms on the electronic density distributions, as well as their effect on HOMO and LUMO orbitals were also investigated.
Hein, Oliver. "Semi-empirical tight-binding ways and means for the atomistic simulation of materials." [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=958752648.
Full textScoging, Helen Mary. "A theoretical and empirical investigation of soil erosion in a semi-arid environment." Thesis, London School of Economics and Political Science (University of London), 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308942.
Full textHaasbroek, Adriaan Lodewicus. "Advanced control with semi-empirical and data based modelling for falling film evaporators." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/80196.
Full textENGLISH ABSTRACT: This work focussed on a local multiple chamber falling film evaporator (FFE). The FFE is currently under operator control and experiencing large amounts of lost production time due to excessive fouling. Furthermore, the product milk dry mass fraction (WP) is constantly off specification, negatively influencing product quality, while the first effect temperature (TE1) runs higher than the recommended 70°C (this is a main cause of fouling). A two month period of historical data were received with the aim to develop a controller that could outperform the operators by keeping both control variables, WP and TE1, at desired set points while also increasing throughput and maintaining product quality. Access to the local plant was not possible and as such available process data were cleaned and used to identify two data based models, transfer function and autoregressive with exogenous inputs (ARX) models, as well as a semi-empirical-model. The ARX model proved inadequate to predict TE1 trends, with an average TE1 correlation to historical data of 0.36, compared to 0.59 and 0.74 for the transfer function and semi-empirical-models respectively. Product dry mass correlations were similar between the models with the average correlations of 0.47, 0.53 and 0.51 for the semi-empirical, transfer function and ARX models respectively. Although the semi-empirical showed the lowest WP correlation, it was offset by the TE1 prediction advantage. Therefore, the semi-empirical model was selected for controller development and comparisons. The success of the semi-empirical model was in accordance with previous research [1] [2] [3], yet other studies have concluded that ARX modelling was more suited to FFE modelling [4]. Three controllers were developed, namely: a proportional and integral (PI) controller as base case, a linear quadratic regulator (LQR) as an optimal state space alternative and finally, to make full use of process knowledge, a predictive fuzzy logic controller (PFC). The PI controller was able to offer zero offset set point tracking, but could not adequately reject a feed dry mass (WF) disturbance (as proposed and reported by Winchester [5]). The LQR was combined with a Kalman estimator and used pre-delay states. In order to offer increased disturbance rejection, the feedback gains of the disturbance states were tuned individually. The altered LQR and PFC solutions proved to adequately reject all modelled disturbances and outperform a cascade controller designed by Bakker [6]. The maximum deviation in WP was a fractional increase of 0.007 for LQR and 0.005 for FPC, compared to 0.012 for PI and 0.0075 for the cascade controller [6] (WF disturbance fractional increase of 0.01). All the designed controllers managed to reduce the standard deviation of operator controlled WP and TE1 by at least 700% and 450%, respectively. The same level of reduction was seen for maximum control variable deviations (370%), the integral of the absolute error (300%) and the mean squared error (900%). All these performance metrics point to the controllers performing better than the operator based control. In order to prevent manipulated variable saturation and optimise the feed flow rate (F1), a fuzzy feed optimiser (FFO) was developed. The FFO focussed on maximising the available evaporative capacity of the FFE by optimising the motive steam pressure (PS), which supplied heat to the effects. By using the FFO for each controller the average feed flow rate was increased by 4.8% (±500kg/h) compared to the operator control. In addition to flow rate gain, the controllers kept TE1 below 70°C and WP on specification. As such, the overall product quality also increased as well as decreasing the down time due to less fouling.
AFRIKAANSE OPSOMMING: Hierdie projek het op ‘n vallende film verdamper (VFV) gefokus. Die VFV word tans beheer deur operateurs en ondervind groot hoeveelhede verlore produksie tyd a.g.v oormatige aangroeisels. Die vorming van aangroeisels is grootliks te danke aan die eerste effek temperatuur (TE1) wat gereeld 70°C oorskrei. Die produk droë massa fraksie (WP) is ook telkens nie op die gewenste vlak nie, wat produk kwaliteit negatief beinvloed. Data, wat oor ‘n twee maand periode strek, was verkry met die doelstelling om ‘n beheerder te ontwerp wat beter sou vaar as die operateurs, deur beide WP en TE2 om ‘n nou stelpunt te beheer. Ter selfde tyd moet die ontwerpte beheerder die produksie tempo en produk kwaliteit verhoog. Geen toegang tot die plaaslikke VFV was moontlik nie, dus was die data skoongemaak en gebruik om twee data gebasseerde modelle te identifiseer, nl. oordragsfunksie en outoregressiwe met eksogene insette (ORX) modelle, asook ‘n semi-empiriese model. Die ORX model kon nie TE1 goed voorspel nie, met ‘n korrelasie faktor (tot die historiese data) van 0.36, vergeleke met die 0.59 en 0.74 van die oordragsfunksie en semi-empiriese modelle onderskeidelik. WP korrelasie faktore was meer konstant tussen die modelle, met waardes van 0.47, 0.53 en 0.51 vir die semi-empiriese, oordragsfunskie en ORX modelle onderskeidelik. Alhoewel die semi-empiriese model die laagste WP korrelasie vertoon het, was die tekortkoming vergoed deur die beter TE1 voorspelling. Gevolglik was die semi-empiriese model gebruik vir beheerder ontwerp en vergelyking. Die sukses van die semiempiriese model stem ooreen met vorige studies [1] [2] [3], tog het ander studies al bevind dat die ORX model beter gepas is vir die VFV proses [4]. Drie beheerders was ontwikkel, nl. ‘n proporsionele en integreerder (PI) beheerder as basis geval, ‘n liniêre kwadratiese reguleerder (LKR) as optimale toestands beheer alternatief en laastens ‘n voorspellende wasige logika beheerder (VWB) om volle gebruik van proseskennis te maak. Die PI beheerder kon foutlose volging van die stelpunte lewer, maar kon nie ‘n inset voer droë massa fraksie (WF) versteuring (soos voorgestel en weergegee deur Winchester [5]) na wense verwerp nie. Die LKR was saamgevoeg met ‘n Kalman afskatter en het gebruik gemaak van onvertraagde toestande. Die versteuringstoestande was individueel verstel om beter versteurings verweping te weeg te bring. Die aangepaste LKR en VWB kon beide die WF versteuring verwerp en het beter gevaar as ‘n kaskade beheer oplossing wat deur Bakker [6] ontwerp was. Die WP afwyking is beperk tot ‘n fraksie droë masse verandering van 0.007 vir LKR en 0.005 vir VWB, vergeleke met die afwykings van 0.012 vir die PI beheerder asook die 0.0075 van die kaskade beheerder [6]. Die ontwerpte beheerder kon ook die standaard afwyking van beide WP en TE1 met ten minste 700% en 450% onderskeidelik verminder. Soortgelyke verbeterings was gesien vir die maksimum beheer veranderlikke afwyking (370%), die integraal van die absolute fout (300%) en die gemiddelde fout (900%). Dus het die ontwerpte beheerders wesenlik verbeter op die operateur beheer. Ten einde om gemanipuleerde veranderlikke versadiging te voorkom, asook die voer vloei (V1) te optimiseer, was ‘n wasige logika optimiseerder (WVO) ontwerp. Die WVO het die beskikbare verdampingskapasiteit ten volle benut deur te sorg dat die stoom druk (PS), wat energie verskaf vir verdamping, ge-optimiseerd bly. ‘n Gemiddelde V1 stygging van 4.8% (±500kg/uur), vergeleke met operateur beheer, is waargeneem. Al die beheerders kon steeds die WP en TE1 stelpunte volg en dus TE1 onder 70°C hou (wat verminderde vormasie van aangroeisels tot gevolg gehad het). Daarom het die produk kwailiteit verhoog en die verlore produksie tyd verminder.
Tan, Xiang. "Numerical Investigation of Ship's Continuous-Mode Icebreaking in Level Ice." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for marin teknikk, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-24777.
Full textManoharan, Madhu. "Evaluation of a neural network for formulating a semi-empirical variable kernel BRDF model." Master's thesis, Mississippi State : Mississippi State University, 2005. http://library.msstate.edu/content/templates/?a=72.
Full textMohamed, Fathi Omar Mohamed. "A semi-empirical approach for the interpretation of the bearing capacity of unsaturated soils." Thesis, University of Ottawa (Canada), 2006. http://hdl.handle.net/10393/27396.
Full textJones, Gareth. "Investigation of the electronic conduction of large molecules via semi-empirical electronic structure techniques." Thesis, Cardiff University, 2012. http://orca.cf.ac.uk/42005/.
Full textEksteen, Jacobus Johannes, M. A. Reuter, and S. M. Bradshaw. "A generic, semi-empirical approach to the stochastic modelling of bath-type pyrometallurgical reactors." Thesis, Stellenbosch : University of Stellenbosch, 2004. http://hdl.handle.net/10019.1/14771.
Full text388 leaves printed on single pages, preliminary pages i- xv and numbered pages 1-371. Includes bibliography, list of tables and figures.
Digitized at 330 dpi black and white and 330 dpi color PDF format (OCR), using KODAK i 1220 PLUS scanner.
ENGLISH ABSTRACT: Bath type furnaces have become an established technology for the intensive smelting, converting and refining of primary and secondary raw materials. Since these furnaces normally have large inventories, long time constants and complex metallurgies, a dynamic model-based prediction strategy is the only feasible approach to operator decision support and process control. This dissertation presents a semi-empirical approach to the stochastic modelling of bath-type pyrometallurgical reactors, which leads to a generic model type called the Equilib-ARMAX model. The modelling approach is applied to three case studies: • A nickel-copper matte converting operation using a submerged lance injection reactor • A chromite smelting operation to produce high carbon ferrochrome using a direct current (DC) plasma smelting furnace • An ilmenite smelting operation to produce high titania slag and pig iron, using a direct current (DC) plasma smelting furnace. In each case, the industrial operations were analysed with regard to the practical and technological constraints which influence the type and quality of the process data. The fundamental process phenomena associated with each operation have been analysed to ascertain which fundamental variables should be included within the overall semi-empirical approach, without sacrificing model transparency, simplicity, accuracy and calculation time. It was considered that an overly complex model would be inappropriate given that data from industrial smelting operations show significant random variance. The thermochemistry and phase equilibria associated with each operation are discussed in detail, as they become the fundamental backbone of the semi-empirical models. The equilibria have been modelled with software that uses non-ideal solutions models and Gibbs free energy minimisation to predict the phase and chemical equilibria that could be expected for a given feed recipe and operating temperature. As the thermodynamic modelling software is not stable within an industrial environment, an artificial intelligent mapping technique has been developed to map process inputs to equilibrium outputs. A multi-layer perceptron neural network has been used as the convenient mapping method to represent equilibrium. The neural networks were trained using tens of thousands of feed recipes, where the feed component ratios were varied based on a 3N factorial design. The amounts and chemistries of all equilibrium phases could be calculated with high accuracies (R2 > 0.95) in all cases. Further stochastic analysis and modelling require additional information about the property distributions associated with each measurement. The homogeneities of the furnace products (slag, alloy and flue dust) critically influence the level of confidence that one can associate with plant measurements. The homogeneities were characterised for the DC plasma arc furnaces and they were benchmarked against a submerged arc furnace. It was found that the homogeneity varied per element, with silicon and sulphur tending to show highest variations in the alloy melts. The observation that the variation in these two elements are both high can partially be attributed to the fact that SiS evaporates from the bath surface, especially in regions close to the arc attachment zone. A significant negative correlation was found between the relative standard deviation per tap (using silicon) and the degree of superheat / subcooling of the alloy, indicating that the homogeneity can be strongly influenced by the changes in rheology due to subcooling below the liquidus (which leads to the precipitation of solid phases and increases the observed melt viscosity). Mixedness or homogeneity and data uncertainty are therefore inseparably linked. The relative standard deviations associated with the homogeneity characterisation, as well as known sampling and assaying variances were used to develop reconciled material balances based on measured plant data. Material balance closure was therefore obtained within the inherent uncertainties of the plant data. Biases in the plant data were identified simultaneously with data reconciliation. Moreover, it was shown using Fast Fourier Power Spectra and statespace analysis that the data reconciliation was a good low-pass filter, as it extracted the major process trends components in the noisy data and it also improved the overall dynamic behaviour characteristics of the data. Finally systems identification techniques were used to develop dynamic transfer function models that were linear in the parameters to be estimated. These systems models were based on the reconciled plant data and equilibrium predictions. The final systems models are therefore equilibrium-autoregressive-moving-average models with exogenous variables (Equilib-ARMAX). The model parameters can be estimated recursively using a simple least squares method. The final models could dynamically predict the metallurgy of the subsequent tap 4-6 hours in advance, based on a given suite of set-points, within the inherent accuracy of the data. These models may be used to suggest the optimal operating conditions through an operator guidance system, or more simply, the models are simple enough to be used in a spreadsheet on a manager's desk.
AFRIKAANSE OPSOMMING: Bad-tipe oonde is reeds 'n gevestigde tegnologie wat algemeen gebruik word vir die intensiewe smelting, omsetting en raffinering van primere en sekondere roumateriale. Aangesien hierdie oonde normaalweg groot inventarisse, lang tydkonstantes en komplekse metallurgiee het, is dinamiese, modelgebaseerde voorspelling die enigste uitvoerbare benadering tot operateur besluitnemingsteunstelsels en prosesbeheer. Hierdie proefskrif stel 'n nuwe generiese, semi-empiriese benadering voor om die bad-tipe oonde stogasties te modelleer en lei tot die sogenaamde Equilib-ARMAX model. Die modelleringsbenadering word geevalueer deur drie gevallestudies: • 'n Nikkel-koper swawelsteen omsettingsproses in 'n dompel-Ians inspuit reaktor • 'n Chromiet smeltingsproses om hoe-koolstof ferrochroom te produseer in 'n gelykstroom (GS) plasmaboogoond • 'n Ilmeniet smeltingsproses om hoe titania slak en ruyster te produseer in 'n gelykstroom (GS) plasmaboogoond. In elke geval is die industriele prosesse ontleed met betrekking tot die praktiese en tegnologiese beperkings wat die tipe en die gehalte van die prosesdata beinvloed. Die fundamentele prosesgedrag van elke proses is ontleed om te bepaal welke fundamentele veranderlikes ingesluit moet word in die semi-empiriese benadering, sonder om model deursigtigheid, eenvoud, akkuraatheid en berekeningstyd in te boet. Die ontwikkeling van oor-komplekse modelle is beskou as ongepas, gegewe dat die data van industriele smeltingsprosesse beduidende onsekerhede toon. Die termochemiese en fase-ewewigte geassosieer met elke proses word breedvoerig bespreek, aangesien dit die fundamente1e grondslag van die semi-empiriese modelle verskaf. Die ewewigte is gemodelleer met rekenaar simulasie-programmatuur wat nie-ideale oplossingsmodelle en Gibbs vrye-energie minimering gebruik om die fase en chemiese ewewigte, wat verwag kan word vir 'n gegewe toevoerresep en bedryfstemperatuur, te voorspel. Aangesien termodinamiese modelleringsprogrammatuur normaalweg nie stabiele gedrag toon in 'n intydse industriele omgewing nie, word kunsmatig intelligente projeksietegnieke gebruik om prosesinsette te projekteer na die ekwavilente ewewigsvoorspellings. 'n Multilaag perseptron neurale netwerk is gebruik as 'n eenvoudige metode om hierdie ewewigsprojeksies voor te stel. Die neurale netwerke is afgerig deur van tienduisende toevoer resepte gebruik te maak. Die verhoudings van die komponente in die voer is gewissel gebaseer op 'n 3N faktoriaalontwerp. Die hoeveelhede en samestelling van al die ewewigsfases kon in alle gevalle bereken word met hoe akkuraatheid (R2 > 0.95). Verdere stogastiese analise en modellering is slegs moontlik met kennis oor die eienskapsverspreidings geassosieer met elke komponent. Die homogeniteite van die oondprodukte (slak, legering en vlieg-as) bepaal, tot 'n groot mate, die betroubaarheidsvlak van die aanlegmetings. Homogeniteite is gekarakteriseer vir die GS-plasmaboogoonde en is vergelyk met die homogeniteite wat in dompelboogoonde gevind word. Die homogeniteite het gevarieer per komponent. Silikon en swawel neig om die grootste ruimtelike variasies te toon in die legerings wat bestudeer is. 'n Beduidende negatiewe korrelasie is gevind tussen die relatiewe standaardafwyking per tap (gebaseer op silikon) en die graad van superverhitting / onderverkoeling van die legering. Dit dui aan dat die homogeniteit sterk beinvloed word deur veranderinge in die smelt reologie. Vermenging, reologie, homogeniteit en data onsekerheid (integriteit) is daarom ten nouste gekoppel. Die relatiewe standaardafwykings geassosieer met die homogeniteitsbepaling, asook die monsternemings- en ontledingsvariansies, is gebruik om die aanlegdata te rekonsilieer onderhewig aan die behoud van die komponent en totale stroom massabalanse. Die massabalanse is dus gesluit deur aanpassings aan die metings te maak binne die inherente onsekerhede in die data. Sistematiese foute in die data is gelyktydig met die rekonsiliasie geidentifiseer. Verder is deur diskrete Fourier energiespektra en toestand-ruimte analises getoon dat massabalans-rekonsiliasie dien as 'n goeie seinfilter om hoe-frekwensie geraas te verminder en tergelykertyd die dinamiese gedragseienskappe van die data te verbeter. Stelsel-identifikasietegnieke is gebruik om dinamiese oordragsfunksiemodelle te ontwikkel wat linieer is met betrekking tot die modelparameters. Hierdie stelselmodelle is gebaseer op gerekonsilieerde data, eksogene prosesdata en ewewigsberekeninge, en word vervolgens ewewigs-autoregressiewe-lopende-gemiddelde modelle met eksogene veranderlikes (Equilib ARMAX) genoem. Die modelparameters kan deur gewone kleinste-kwadrate metodes beraam word. Die finale modelle kan die metallurgie van toekomstige tappe 4-6 uur voortydig voorspel, gebaseer op beskikbare stelpunte en binne die inherente presisie van die data. Hierdie modelle kan gebruik word om optimale bedryfskondisies vir prosesbeheer te identifiseer, en is eenvoudig genoeg om in sigbladformaat op 'n aanlegbetuurder se rekenaar gebruik te kan word.
Gibson, Joshua S. "From Development of Semi-empirical Atomistic Potentials to Applications of Correlation Consistent Basis Sets." Thesis, University of North Texas, 2014. https://digital.library.unt.edu/ark:/67531/metadc500219/.
Full textKillough, Brian D. "A semi-empirical cellular automata model for wildfire monitoring from a geosynchronous space platform." W&M ScholarWorks, 2003. https://scholarworks.wm.edu/etd/1539623419.
Full textHuang, Xin. "Bootstrap and Empirical Likelihood-based Semi-parametric Inference for the Difference between Two Partial AUCs." Digital Archive @ GSU, 2008. http://digitalarchive.gsu.edu/math_theses/54.
Full textTruxon, James M. "Semi-Empirical Lifetimes for High-Energy Rydberg States of ¹³³Cs Neutral Cesium in a Blackbody Radiation Field." University of Toledo / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1356809390.
Full textDisotell, Kevin James. "A semi-empirical model of the wall-normal velocity induced by flow-shaping plasma actuators." Connect to resource, 2010. http://hdl.handle.net/1811/45413.
Full textAddari, Daniele. "A semi-empirical approach for the modelling and analysis of microvibration sources on-board spacecraft." Thesis, University of Surrey, 2017. http://epubs.surrey.ac.uk/813167/.
Full textGoes, Adriano Almeida 1978. "Modelo de propagação empírico para sistemas RFID passivo = Emprirical propagation model for RFID passive systems." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/261045.
Full textTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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Resumo: Resultados de campanhas de medição realizadas visando o desenvolvimento de uma fer-ramenta para o projeto, implantação e análise de sistemas de RFID são mostrados nesse traba-lho. Particularmente, a perda de percurso de rádio a partir de um leitor de RFID até um TAG, e de volta para o leitor é caracterizada na banda 915 MHz, para diferentes distâncias de separação leitor-TAG, alturas de TAG e de antena do leitor. Vários cenários de propagação foram considerados, incluindo ambientes exteriores e in-teriores, para os quais foi colhido um extenso número medidas. Os dados de campo são, então, comparados a uma versão melhorada do modelo clássico perda caminho 2-ray, ajustada para incluir também os padrões de radiação da antena não omnidirecionais no leitor. Além disso, foi investigado, por meio da análise de medidas de campo, o efeito da mobi-lidade do TAG no sinal recebido no leitor. Para a coleta das medidas, foi construído um aparato composto de uma esteira de velocidade controlada, onde foram instalados TAGs de teste. Os resultados de medida mostraram que a mobilidade do TAG provoca uma diminuição do valor médio e um aumento da variância do sinal recebido no leitor. Essa atenuação extra e a variância do sinal não são fortemente afetadas pelo valor da velocidade. Por fim, esses efeitos de propagação são incorporados em um modelo matemático, que pode ser utilizado para a simulação e planejamento de sistemas RFID
Abstract: Results of measurement campaigns carried out aiming at the development of a tool for design, deployment, and analysis of RFID systems are shown. Particularly, the radio path loss from an RFID reader towards the test TAG and back to the reader is characterized at the 915 MHz band. The path loss is estimated based on the received signal strength measured at the reader, for different reader¿TAG separation distances and different antenna TAG heights. Several propagation scenarios have been considered, including outdoor and indoor environments for which an extensive number of typical real manufacturing plants have been chosen. The field data are then compared to a proposed novel, improved version of the classical 2-ray path loss model, adjusted to include non-omnidirectional antenna radiation patterns at the reader. In addition, the effect of TAG mobility in the received signal at the reader was also investigated, by means of field measurements. To collect the field measurements, an apparatus was designed and constructed, consisting of a mat of controlled speed, on which test TAGs were installed. The results showed that TAG mobility decreases the average value increases the variance of the received signal at the reader. This extra attenuation and the increased variance of the signal are not strongly affected by the value of speed. Finally, these two effects are incorporated into a mathematical model that can be used for simulation and planning of RFID systems
Doutorado
Telecomunicações e Telemática
Doutor em Engenharia Elétrica
Williams, Christopher Wyn. "The development of a semi-empirical model for the prediction of wind loading on building roofs." Thesis, University of Nottingham, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260700.
Full textGerek, Zeynep Nevin. "Semi-Empirical Correlation of Transport Properties Based on the Step Potential Equilibria and Dynamics (SPEAD) Model." University of Akron / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=akron1145578709.
Full textSeverholt, Josefine. "Generic 6-DOF Added Mass Formulation for Arbitrary Underwater Vehicles based on Existing Semi-Empirical Methods." Thesis, KTH, Marina system, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-211170.
Full textAutreto, Pedro Alves da Silva 1983. "Estrutura eletrônica de melaninas solvatadas." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/277665.
Full textDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin
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Resumo: As melaninas constituem uma classe de pigmentos biológicos de destaque devido, sobretudo, a sua predominante presença nos tecidos dos mamíferos. Há fortes evidências que sugerem que a pigmentação por melanina tem por objetivo proteger a pele contra efeitos prejudiciais da radiação ultravioleta. Além deste papel de fotoproteção, outras funções biológicas são especuladas em razão da presença do pigmento em regiões não iluminadas do corpo como por exemplo no cérebro em que há uma aparente destruição preferencial das células que contém melanina quando ocorrem doenças como o mal de Parkinson. Apesar de décadas de investigações, nenhuma amostra de melanina foi estruturalmente bem caracterizada. Dentre os diversos obstáculos que são responsáveis pelo lento progresso que marca a pesquisa deste pigmento, o maior deles é que as melaninas naturais são altamente insolúveis e de presumido alto peso molecular. Pesquisas recentes desenvolvem sínteses alternativas para as melaninas utilizando outros solventes e demonstram que até 20 % da estrutura desta pode ser composta por água. Assim, neste trabalho investigamos, por métodos quânticos, a geometria e estrutura eletrônica das moléculas 5,6 indolquinona, suas formas reduzidas (semiquinona e hidroquinona) e 27 dímeros obtidos a partir destas, em seus estados neutros e iônicos ( ± 1 e ± 2), no vácuo e nos solventes DMF(dimetilformamida), DMSO (dimetilsulfóxido) e água. Verificamos como o solvente altera as propriedades eletrônicas e espectroscópicas destas estruturas e como este pode ser fundamental para a determinação de suas geometrias. Utilizamos dois modelos para simular o solvente: um modelo contínuo, COSMO (Conductor-like Screening Model) e um discreto, que considera explicitamente cada molécula do solvente e é baseado em simulações Monte Carlo. Notamos que o solvente altera a propriedade de aceitador de dois elétrons de diversas estruturas, fato até então não observado e de importante consequência biológica, visto as eumelaninas poderem ser base de um mecanismo de defesa celular contra radicais livres. Os picos dos espectros de absorção, de um modo geral, são deslocados para o vermelho e, em alguns casos, tem um alargamento. Isto poderia contribuir para a constrção da larga banda característica das eumelaninas. Diversos outros aspectos importantes, em excelente acordo com dados experimentais, são também apresentados ao se considerar o solvente. Um dos mais relevantes mostra que o solvente tem forte influência na geometria da molécula com o menor custo de dimerização, o que nos leva a concluir que esta pode ser de fato a semente de "nucleação" para a formação do polímero de melanina.
Abstract: Melanins belong to an important class of biological pigments due to its abundant presence in mamal tissues. There are strong evidences that suggest that the pigmentation due to melanin would protect the skin against the biochemical devastation induced by solar exposure. Besides the photo-protection feature, other biological functions have been speculated to melanin due to its presence in non-illuminated areas of the body and the apparent preferential destruction of melanin-containing cells in the substancia nigra of the brain in Parkinsonism. Unfortunately, in what concerns structural and chemical composition, no melanin sample has been fully and unambiguously characterized yet, despite the enormous amount of experimental work done so far. The main difficulty for that is that melanin is insoluble in most organic solvents and has high molecular weight. A new synthetic route for melanins, using organic solvents, has been recently achieved and it was demonstrated that about 20 % of the structure of the pigment is composed by water. In this work we have investigated using quantum methods the geometries and electronic structure of 5,6 indolquinone, their redox forms (semiquinone and hidroquinone) and 27 dimers associated, in their neutral and ionic states ( ± 1 e ± 2). The calculation were carried in vacuum and in the solvents dimethyl sulfoxide (DMSO), N,N-dimethyl formamide (DMF) and water. We study the effect of the solvent on the electronic and spectroscopic properties and its importance to determine eumelanin structure. Two models for solvents were used. The first was a continuum model, COSMO (Conductor-like Screening Model), and the second one (based on Monte Carlo simulations) explicitly considers each molecule of the solvent. The results showed that the solvents affected the electron accepton properties allowing the acceptance of two electrons. These aspects have been not been observed before from vacuum calculations and it is of important biological consequence because the melanins can be the base of mechanism of cellular defense against free radicals. The peaks of absorption spectra of the solvated structure are dislocated from red and broadened. This could contribute to the characteristic broad band of eumelanins. Many others important aspects are in better agreement with experimental data when solvent aspects are explicitly taken into account. One of most important results was the observation that solvent effects can alter the order of the lowest energy dimer configuration in relation to the structures in vacuum. This dimer was suggested to be the nucleation seed for the polymer formation.
Mestrado
Física Atômica e Molecular
Mestre em Física
Sardón, Tupayachi Talía del Carmen, and Salazar Angelo Paolo Sasaky. "Estudio comparativo entre la capacidad de carga de pilotes excavados, estimados mediante métodos analíticos, semiempiricos y pruebas de carga. Aplicaciones en suelos gravosos y arcillosos en la costa del Perú." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2020. http://hdl.handle.net/10757/652236.
Full textThis thesis analyzes the static methods, which include the analytical and semi-empirical methods that are used to determine the theoretical load capacity in piles, and compares them with the dynamic load tests, which provide the real result of the load capacity of a pile. The analysis compiles the theories of Therzaghi, Hansen, Meyerhof and Bowles, regarding the analytical models, and the theories of Aoki Velloso, Decourt Quaresma, Pedro Paulo Velloso and Texeira, by the semi-empirical theories.
Tesis
Amer, Mariam. "Using Semi-Empirical Models For Predicting The Luminescence –Structure Relationships in Near-UV Excited Phosphors Activated with Divalent Europium or Mercury-like Cations." Thesis, Université Clermont Auvergne (2017-2020), 2017. http://www.theses.fr/2017CLFAC069/document.
Full textThe most used strategy for the design of new luminescent materials today is based on trial-error methods. However, these methods may often result in consummation of money and time. In this sense, a theoretical model acting as a predictive tool can serve as an alternative strategy. Such models are also studied and used by scientists around the world but they are mostly difficult to use. In this work, two friendly and easy to use semi-empirical theoretical models were proposed as a criterion for designing phosphors integrated in the development of important technologies especially in LED-based lightings and solar cells. These models are: 1) the environmental factor model (EF) based on the dielectric theory of chemical bonding proposed by Philips and 2) the metal to metal charge transfer (MMCT) model by Boutinaud that were both used for the purpose of finding relationships between the structural properties of a material and its luminescence. The EF model was applied on the family of AIBIIPO4 (AI= monovalent cation, BII= divalent cation) compounds doped with Eu2+. It was able to estimate the excitation edge energy and to identify the doping sites within uncertainty of ± 1000 cm-1. It can therefore, be used for the design of new phosphors belonging to this family. In a second part, both models were used to identify the nature of luminescence in Bi3+-doped oxides. For this purpose, a method combining the mentioned models along with the values of the Stokes shift was found reliable. In addition, the method was found useful to explain the change in luminescent properties of YVO4:Bi3+ under high pressure. In the third part, the two models were used to explore the luminescence of Sb3+-doped oxides by analogy with Bi3+. However, the results were not good enough to identify the nature of luminescence in these materials. The reason could be related to the off-centered position of the dopant (Sb3+)
Atkinson, Michael D. "Control of Hypersonic High Angle-Of-Attack Re-Entry Flow Using a Semi-Empirical Plasma Actuator Model." University of Dayton / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1335283726.
Full textAlzaili, Jafar S. L. "Semi-empirical approach to characterize thin water film behaviour in relation to droplet splashing in modelling aircraft icing." Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/7849.
Full textQuaife, T. L. "The potential of SPOT-4 VGT to derive information on earth surface properties using semi-empirical BRDF models." Thesis, Swansea University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638596.
Full textHousley, Paul. "Semi-empirical prediction of the normal aerodynamic loads on axisymmetric bodies of arbitrary profile in non-uniform flowfields." Thesis, University of Bristol, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.432733.
Full textShen, Chen. "Application of Fuel Element Combustion Properties to a Semi-Empirical Flame Propagation Model for Live Wildland Utah Shrubs." BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/3550.
Full textMarçal, Nei. "Estudo da estrutura eletrônica e das propriedades ópticas de copolímeros formados por vinilenos e anéis de tiofeno." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/277368.
Full textTese (doutorado) - Universidade Estadual de Campinas, Instituto de Fisica Gleb Wataghin
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Resumo: Antes da década de 70, todos os materiais poliméricos eram considerados como isolantes e suas aplicações tecnológicas levavam em conta esta característica. De lá para cá, uma nova classe desses materiais, os polímeros conjugados, determinaram uma nova forma de aplicação de sistemas poliméricos baseados em suas propriedades elétricas e de ótica não-linear. Um maior estímulo surgiu a partir do experimento de Mac Diarmid, Heeger e Shirakawa [1] que, expondo o Poliacetileno a agentes oxidantes, demonstraram ser possível obter um sistema no estado metálico. Atualmente encontramos filmes de Poliacetileno com condutividade elétrica da ordem do cobre (105 S/cm). O Poliacetileno, quando no regime metálico, i.e., sob alta dopagem, apresenta algumas características de metal comum: alta condutividade elétrica (cresce 13 ordens de grandeza), susceptibilidade de Pauli finita e absorção no infravermelho. Já outras propriedades como a presença de modos vibracionais localizados no infravermelho e o não comportamento da condutividade com o inverso da temperatura evidenciam ser este um material não usual. Estes polímeros conjugados que apresentam uma extensiva delocalização de elétrons são considerados semicondutores orgânicos com gap de energia relativamente pequeno, da ordem de 1,5 a 2,0 eV. O comportamento semicondutor e as propriedades decorrentes entre os elétrons e a luz têm originado a construção de vários dispositivos semicondutores e optoeletrônicos [2, 7, 3]. Problemas técnicos como estabilidade ao ambiente, processabilidade e solubilidade destes materiais provocaram a produção de uma nova classe de materiais poliméricos que foi obtida por polimerização eletroquímica [57, 58, 59] cuja estrutura molecular trata-se de sistemas que introduzem grupos vinilas (V) entre anéis de tiofeno (T). Experimentos de voltametria cíclica, espectroscopia de absorção ótica e ressonância eletrônica de spin indicam que esses sistemas possuem potencial de ionização e gap de energia menores que o apresentado pelo Politiofeno. Estudos com oligômeros de tiofeno (T) com vinilenos (V) sugerem a possibilidade de escolha desse material como alternativa ao politiofeno. O objetivo deste trabalho foi investigar teoricamente a influência do grupo vinila (V) sobre as propriedades eletrônicas nestes polímeros, reproduzir os resultados experimentais e determinar qual proporção de vinilenos (V) e tiofenos (T) que provoque o menor gap de energia de forma que quando sobre dopagem possibilite uma transição isolante metal. Desta maneira, primeiramente, determinamos as geometrias dos sistemas de interesse utilizando métodos semi-empíricos. Posteriormente investigamos a estrutura eletrônica dos polímeros de tiofeno (T) com vinilenos (V), sendo que estes polímeros foram estudados para o caso neutro e na presença de defeitos conformacionais do tipo pólaron e bipólaron. Finalizamos o estudo investigando as absorções ópticas UV-vis dos sistemas de interesse através de cálculos semi-empíricos utilizando o código ZINDO/S.
Abstract: Before the 1970s, all polymeric materials were considered insulators; therefore their technological applications would take this trait into account. Since then, a new development on these materials, the conjugated polymers, determined new applications for polymeric systems based in their electrical and nonlinear optical properties. Greater interest arose from the experiment by Mac Diarmid, Heeger and Shirakawa [1] who, by using polyacetylene and oxidizing agents, showed that it is possible to obtain a system in the metallic state. Nowadays it is possible to find polyacetylene films with electrical conductivity of the order of copper (10-5 S/cm). Polyacetylene, when in its metallic behavior, i.e., under high dopage, presents some characteristics of real metal: high electrical conductivity (increased by 13 orders of magnitude), finite Pauli susceptibility and infrared absorption. On the other hand, other properties such as the presence of vibrational modes localized on infrared and the odd behavior of conductivity versus the inverse of temperature make clear that this is a unusual material. These conjugated polymers, presenting an extensive delocalization of electrons, are considered organic semiconductors with relatively low energy gap, of the order of 1.5 to 2.0 eV. The semiconductive behavior and the resulting properties of the interaction between electrons and light have been the drive for the manufacturing of several semiconductor and optoelectronic devices [2, 7, 3]. Technical problems, such as environmental stability, processability and solubility of these materials, gave rise to the production of a new kind of polymeric materials that were obtained by electrochemical polymerization [57, 58, 59], in which the molecular structure is a system that introduces vinylene groups (V) between tiophene rings (T). Experiments involving cyclic voltametry, optical absorption spectrometry and spin electronic ressonance indicate that these systems have ionization potential and energy gap smaller than those presented by Polythiophene. Studies with thiopene oligomers (T) with vinylene (V) suggest this material can be chosen as an alternative to Polytiophene. The goal of this work is to theoretically investigate the in uence of the vinyle group (V) on the electronic properties on these polymers, reproduce experimental results and determine what is the vinylene (V) to thiophene (T) rate that causes the smallest energy gap, such that doping will produce a insulator-metal transition. Therefore, we first determine the target systems' geometry using semi-empirical methods. Then we investigate the electronic structure of the tiophene (T) and vinylene (V) polymers both for neutral systems and in the presence of conformational defects of polaron and bipolaron types. We nalized the study by investigating the UV-vis optical absorption of the target systems through semi-empirical calculations using ZINDO/S code.
Doutorado
Estrutura Eletronica de Atomos e Moleculas ; Teoria
Doutor em Ciências