Teses / dissertações sobre o tema "Loss surface"
Crie uma referência precisa em APA, MLA, Chicago, Harvard, e outros estilos
Veja os 50 melhores trabalhos (teses / dissertações) para estudos sobre o assunto "Loss surface".
Ao lado de cada fonte na lista de referências, há um botão "Adicionar à bibliografia". Clique e geraremos automaticamente a citação bibliográfica do trabalho escolhido no estilo de citação de que você precisa: APA, MLA, Harvard, Chicago, Vancouver, etc.
Você também pode baixar o texto completo da publicação científica em formato .pdf e ler o resumo do trabalho online se estiver presente nos metadados.
Veja as teses / dissertações das mais diversas áreas científicas e compile uma bibliografia correta.
Booman, Richard Albert 1957. "DETERMINATION OF LOSS MECHANISMS IN LONG RANGE SURFACE PLASMON MODES". Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/275490.
Texto completo da fonteWright, Samantha C. "Understanding the mechanisms behind surface elevation loss in ditched marshes". Thesis, Boston University, 2012. https://hdl.handle.net/2144/12682.
Texto completo da fonteLoss of surface elevation makes salt marshes more susceptible to impacts from accelerated sea level rise, such as vegetation drowning, die-off, and conversion of marsh to open water. The ultimate degradation of the salt marsh system is disastrous with ramifications ranging from loss of critical habitat to loss of an important buffer for coastal communities from storm surges. Effectively, a more comprehensive understanding of the mechanisms driving surface elevation loss in anthropogenically altered and degraded marshes is key to engineering successful marsh restoration projects, in an effort to reverse this trend. This study aims to achieve that goal in an area of a northern Massachusetts salt marsh with high man-made ditch density, through comparison of the hydrologic, sedimentary, and vegetative conditions to a non-ditched, reference portion of salt marsh. It was hypothesized that a decrease in subsurface hydroperiod through increased drainage, characteristic of areas of high ditch density, would allow for increased oxygen diffusion into the subsurface causing belowground decomposition rates to increase. This ultimately would lead to a reduction in organic matter, and without compensation from an inorganic sediment supply, marsh subsidence would occur. Water table levels, belowground biomass, bulk density data, and percent organic content data all supported this hypothesis, but direct analysis of the belowground litterbag component of this study did not demonstrate significant differences in decomposition rates between the ditched and non-ditched sites. Further study of belowground conditions, resulted in a live root turnover rate about twenty percent slower in the ditched marsh than in the non-ditched marsh. This suggests that turnover rates, not decomposition rates, may ultimately be the mechanism behind surface elevation loss in ditched marshes.
Nicoletti, Olivia. "Mapping surface plasmons of metal nanoparticles with electron energy-loss spectroscopy". Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608025.
Texto completo da fonteOliver, Trevor N. "Surface acoustic wave devices with low loss and high frequency operation". Thesis, Aston University, 1989. http://publications.aston.ac.uk/8083/.
Texto completo da fonteOh, Tchang-hun. "Control of lateral diffraction loss in vertical-cavity surface-emitting lasers /". Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
Texto completo da fonteGu, Xiaoxiong. "Modeling effects of random rough surface on conductor loss at microwave frequencies /". Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/5831.
Texto completo da fonteBeasley, Jeffrey S. "Nitrogen Regime Influence on Nutrient and Sediment Surface Runoff During Vegetative Establishment of Bermudagrass". Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/31900.
Texto completo da fonteMaster of Science
Dienes, Susanna. "Beneath the Surface". ScholarWorks@UNO, 2007. http://scholarworks.uno.edu/td/1058.
Texto completo da fontePrior, Mark Kevan. "Low frequency sound propagation in sea surface mixed layers in the presence of internal waves". Thesis, University of Southampton, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243119.
Texto completo da fonteFinke, Manuela. "Studying food-related demineralisation of teeth with atomic force microscopy (AFM) and nanoindentation". Thesis, University of Bristol, 2001. http://hdl.handle.net/1983/8d6de76b-d940-47ad-b0f6-095f56ddf54e.
Texto completo da fonteMeneses, Bruno Miguel do Carmo Santana. "Influência de um fogo florestal na qualidade da água da Ribeira de São Domingos localizada na Região Oeste de Portugal". Master's thesis, ISA, 2013. http://hdl.handle.net/10400.5/6489.
Texto completo da fonteForest fires are responsible for several environmental problems, especially for polluting watercourses. In this dissertation we intend to evaluate the changes occurring in the physical and chemical constitution of water of São Domingos stream (crossing the municipalities of Lourinhã and Peniche, Portugal), in particular pH and nutrient content variation, related to surface runoff from the burnt area of the Cezaredas plateau, where a forest fire occurred at July 19th, 2012. Thus, water samples were collected in three points strategically chosen along this stream (one upstream of the burnt area and two downstream, one of the last being located immediately after the burnt area) from which the pH, the electrical conductivity and the concentrations of N, P, K, Na, Ca and Mg were assessed. The data obtained in the analysis of the samples collected downstream of the burnt area show an input of nutrients in the stream water and an evidence that nutrient transportation occurs in a higher degree during the first episodes of rainfall which are also responsible for generating surface runoff. This is due to the greater availability of nutrients in these areas and the reduced soil protection, a factor that facilitates surface runoff.
Davies, P. R. "Reactions of molecules at surfaces studied by photoelectron and electron energy loss spectroscopies". Thesis, Cardiff University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.305213.
Texto completo da fonteYoung, Michael Howard 1961. "Monitoring near-surface soil water loss with time domain reflectometry and weighing lysimeters". Diss., The University of Arizona, 1995. http://hdl.handle.net/10150/191191.
Texto completo da fonteFlack, Paul E. 1960. "A method for establishing base-line soil loss rates on surface mine sites". Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/276985.
Texto completo da fonteChaudhury, Kreteeka. "An Experimental Investigation of the Impact of Engineered Surface Processes on Efficiency of Spur Gears". The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1556553897979376.
Texto completo da fonteTarkalson, David Dale. "PHOSPHORUS LOSS IN SURFACE RUNOFF FROM PIEDMONT SOILS RECEIVING ANIMAL MANURE AND FERTILIZER ADDITIONS". NCSU, 2001. http://www.lib.ncsu.edu/theses/available/etd-20010926-002603.
Texto completo da fonteThe purpose of this research was to measure P losses in runoff from agricultural land in the Piedmont region of the southeastern U.S. with varying soil P levels and receiving broiler litter and inorganic P fertilizers. The experimental results will be helpful for the development of the P Loss Assessment Tool in North Carolina and other P Index approaches in states with similar soil characteristics and crop management practices. A net influx of P into many areas due to high animal populations has resulted in increased potential P losses to sensitive surface waters. A typical North Carolina broiler farm and dairy farm were found to have annual P surpluses of 65 kg P/ha and 20 kg P/ha respectively. The use of low phytic acid corn varieties and phytase enzyme has the potential to reduce the P surplus on broiler farms by 25 to 58%. Phosphorus losses in runoff from Piedmont conventional till (CT) and no-till (NT) soils with varying soil P concentrations and from soils currently receiving broiler litter and fertilizer P applications were assessed. In these studies, rainfall simulation at rates of 6 and 7.6 cm/hr were utilized to collect runoff samples from crop land with a range of initial P concentrations and from plots with varying fertilizer P and broiler litter application rates, both incorporated and broadcast. Runoff samples were collected at 5-min intervals for 30 min and analyzed for reactive P (RP), algal-available (AAP), and total P (TP). Concentration of RP in runoff from CT and NT plots was positively correlated with Mehlich-3 extractable P (r2 = 0.61 and 0.7 respectively) and oxalate extractable degree of P saturation (DPS) (r2 = 0.6 and 0.61 respectively). However, only TP mass loss (kg TP/ha) in runoff from CT was correlated with DPS (r2 = 0.57). A Mehlich 3 extractable P concentration of 350 mg P/kg and a DPS of 84% corresponded to 1 mg RP/L in runoff. Incorporation of broiler litter and inorganic P fertilizer into the soil at all P application rates virtually eliminated P runoff loses and had similar P losses in runoff as the unfertilized control. Surface application of broiler litter resulted in runoff containing between 2.9 and 24.5 mg RP/L for application rates of 8 to 82 kg P/ha respectively. Mass loss of TP in runoff from surface-applied broiler litter ranged from 1.3 to 8.5 kg P/ha over the same application rates. There was no significant relationship between surface applied inorganic P application rate and RP concentrations or TP mass losses in runoff. However, there was a trend for increased RP concentrations and TP mass losses in runoff with increasing application rate. Concentration of RP and mass loss of TP in runoff from surface applied inorganic P averaged 4.9 mg RP/L and 1.1 kg P/ha over all application rates. There was no significant difference between P losses in runoff from plots receiving surface applied conventional broiler litter and broiler litter derived from birds fed a low phytic acid corn (High Available P corn).
Holman, David. "Surface loss of heteromeric AMPA receptor complexes in response to transient NMDA receptor activation". Thesis, University of Bristol, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.420888.
Texto completo da fonteRyan, Jonathan. "UAV investigation of surface and tidewater mass loss processes across the Greenland Ice Sheet". Thesis, Aberystwyth University, 2018. http://hdl.handle.net/2160/018cf7b7-fc9b-4327-a80e-6ec866193d5f.
Texto completo da fonteSindi, Khalid Hussain F. "In vitro and in vivo feasibility study of ultrasound for monitoring tooth surface loss". Thesis, University of Leeds, 2013. http://etheses.whiterose.ac.uk/6296/.
Texto completo da fonteAcharya, Ananta R. "Indium Nitride Surface Structure, Desorption Kinetics and Thermal Stability". Digital Archive @ GSU, 2013. http://digitalarchive.gsu.edu/phy_astr_diss/62.
Texto completo da fonteBlomdahl, Klara. "Changes in the Cold Surface Layer on a Polythermal Glacier during Substantial Ice Mass Loss". Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-251362.
Texto completo da fonteKlimatförändringar i Arktis och subarktis har orsakat stora förändringar i kryosfären. Ett varmare klimat orsakar en minskning av glaciärers storlek och omfattning och nettomassbalansen för Arktiska glaciärer har varit negativ under de senaste 40 åren. Relativt få studier har genomförts angående utvecklingen av den termiska fördelningen i glaciärer under omfattande volymförändringar. Det finns en möjlig diversitet i hur den termiska strukturen kan ändras med ett förändrat klimat. Storglaciären förlorar det kalla ytskiktet i ablationsområdet och blir successivt mer tempererad, medan Kårsaglaciären förlorar zonen med tempererad is i ablationsområdet och blir därmed kallare. Syftet med den här studien har varit att öka förståelsen för den termiska reaktionen hos polytermala glaciärer till ett förändrat klimat. Resultaten från Pårteglaciären i norra Sverige visar en volymreducering med 18% under de senaste 15 åren med en förväntad minskning på 35% av den nuvarande storleken under det kommande århundradet. Som en följd av det rådande klimatet och den reducerade volymen genomgår det kalla ytskiktet på Pårteglaciären en förtunning med en genomsnittlig hastighet av 1.13 m a-1. Volymförändringarna och förändringarna i kalla ytskiktet är i samma storleksordning, vilket tyder på att CTS anpassas relativt snabbt till de nuvarande förändringarna. Förutsatt en klimatisk effekt liknande den som observerats på Storglaciären, kan slutsatsen dras att förtunningen har påverkat den termiska regimen. Men i motsats till Kårsaglaciären har den termiska fördelningen på Pårteglaciären blivit mer tempererad som ett resultat av den omfattande massförlusten.
Villegas, Juan Camilo, Darin J. Law, Scott C. Stark, David M. Minor, David D. Breshears, Scott R. Saleska, Abigail L. S. Swann et al. "Prototype campaign assessment of disturbance-induced tree loss effects on surface properties for atmospheric modeling". WILEY, 2017. http://hdl.handle.net/10150/623209.
Texto completo da fonteHillborg, Henrik. "Loss and recovery of hydrophobicity of polydimethylsiloxane after exposure to electrical discharges". Doctoral thesis, KTH, Polymer Technology, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3082.
Texto completo da fonteSilicone rubber based on polydimethylsiloxane is used ashigh voltage outdoor insulation, due to its ability to preservethe hydrophobic surface properties during service and evenregain hydrophobicity after exposure to electrical discharges.The underlying processes for the hydrophobic recovery arediffusion of low molar mass siloxanes from the bulk to thesurface and reorientation by conformational changes ofmolecules in the surface region. Only little is known of whichfactors are responsible for the long-term stability of thishydrophobic recovery. It is therefore important to increase theknowledge about the fundamental mechanisms for the loss andrecovery of hydrophobicity of silicone rubbers, exposed toelectrical discharges. Addition-cured polydimethylsiloxanenetworks, with known crosslink densities, were exposed tocorona discharges and air/oxygen-plasma and the loss andrecovery of hydrophobicity was characterised by contact anglemeasurements. The degree of surface oxidation increased withincreasing exposure time with a limiting depth of 100- 150 nm,as assessed by neutron reflectivity measurements. The oxidationrate increased with increasing crosslink density of the polymernetwork, according to X-ray photoelectron spectroscopy. Withinthe oxidised layer, a brittle, silica-like layer was graduallydeveloped with increasing exposure time. The hydrophobicrecovery following the corona or air/oxygen- plasma exposuresoccurred at a slow pace by diffusion of cyclic oligomericdimethylsiloxanes through the micro-porous but uncrackedsilica-like surface layer or at a much higher pace by transportof the oligomers through cracks in the silica-like layer. Theoligomers were present in the bulk, but additional amounts wereformed during exposure to corona discharges. High-temperaturevulcanised silicone rubber specimens were aged in a coastalenvironment under high electrical stress levels (100 V/mm). Thechanges in surface structure and properties were compared tothe data obtained from specimens exposed to coronadischarges/plasma. The dominating degradation mechanism wasthermal depolymerisation, initiated by hot discharges. Thisresulted in the formation of mobile siloxanes, of which the lowmolar mass fraction consisted of cyclic oligomericdimethylsiloxanes. Oxidative crosslinking resulting insilica-like surface layers was not observed during theseconditions.
Keywords:silicone rubber, polydimethylsiloxane,hydrophobicity, corona, air-plasma, oxygen-plasma, surfacecharacterisation, degradation products, crosslink density.
Rabias, J. "Power loss in amorphous ribbon materials : The effect of surface roughness on the power loss and harmonic content of flux density of amorphous ribbon materials". Thesis, Bucks New University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375618.
Texto completo da fonteWANG, AIHUA. "EFFECTS OF FREE SURFACE HEAT TRANSFER AND SHAPE ON THERMOCAPILLARY FLOW OF HIGH PANDTL NUMBER FLUIDS". Case Western Reserve University School of Graduate Studies / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=case1094682055.
Texto completo da fonteBhasin, Amit. "Development of methods to quantify bitumen-aggregate adhesion and loss of adhesion due to water". Texas A&M University, 2003. http://hdl.handle.net/1969.1/5934.
Texto completo da fonteHashim, Nur Zatil Ismah. "Au-compensated high resistivity silicon for low loss microwave devices : suppression of parasitic surface conduction effect". Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/387343/.
Texto completo da fonteZielke, Dimitri [Verfasser]. "Supressing loss channels in the bulk and at the surface of crystalline silicon solar cells / Dimitri Zielke". Hannover : Technische Informationsbibliothek (TIB), 2017. http://d-nb.info/1136297995/34.
Texto completo da fonteAli, Fowziya M. "Investigations of the potential effects of different preventive products on treatment and prevention of enamel surface loss". Thesis, University of Leeds, 2018. http://etheses.whiterose.ac.uk/20567/.
Texto completo da fonteSharma, Sumana. "Genome-scale identification of cellular pathways required for cell surface recognition". Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/271825.
Texto completo da fonteDavis, Daniel E. "A Technique for Evaluating the Uncertainties in Path Loss Predictions Caused by Sparsely Sampled Terrain Data". Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/23314.
Texto completo da fonteThat is accomplished by accurately solving the electromagnetic fields over many randomly rough surfaces which pass through the sparse topographic data points, many possible communication links, all of which fit the underlying data, are represented. The power variation
caused by the different surface realizations is that due to the sparse sampling. Additionally, to verify that this solution technique is a good model, experimental propagation measurements were taken, and compared to the computations.
Master of Science
Monkman, James. "Identification and functional characterisation of TGFB-regulated and cell surface candidates in pancreatic cancer". Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/213218/1/James_Monkman_Thesis.pdf.
Texto completo da fonteChapman, Antony Shaun. "Particulate phosphorus loss from agricultural land via sub-surface drainage in the UK : tracing, modelling and risk assessment". Thesis, Coventry University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365249.
Texto completo da fonteLiu, Chung-Ni. "Laboratory investigation of the effect of the dampening solution on the loss of surface strength of coated paper /". Online version of thesis, 1993. http://hdl.handle.net/1850/11983.
Texto completo da fonteVimercati, Bianca Mataveli. "Influência da aplicação de selantes de superfície na perda de massa e alteração da rugosidade superficial de um compósito após aplicação tópica de flúor fosfato acidulado e ensaio de escovação". Universidade do Estado do Rio de Janeiro, 2007. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=1818.
Texto completo da fonteEste estudo teve por objetivo avaliar a degradação de um compósito após ciclos de escovação simulada, com ou sem a aplicação de selantes de superfície e com ou sem a aplicação tópica de flúor fosfato acidulado (FFA). A avaliação foi feita através da análise alteração da massa e da rugosidade superficial. Foram confeccionados 80 corpos-de-prova (CP) com o compósito Z250 (3M) (8mm x 3mm) e divididos em 4 grupos. Todos os grupos tiveram as superfícies regularizadas com lixa dágua 1.200. O grupo A (controle) não recebeu selamento, o grupo B recebeu aplicação do selante de superfície Fortify (Bisco), o grupo C, BisCover (Bisco) e o grupo D, Fill Glaze (Vigodent). Após isso, os CP foram armazenados em água destilada por 7 dias, em temperatura ambiente e, posteriormente, pesados em balança analítica para obtenção da massa inicial e submetidos à análise da rugosidade superficial inicial, utilizando rugosímetro Surftest SJ 201 P Mitutoyo. Os grupos A, B, C e D foram subdivididos em 2 grupos cada (n:10) e um subgrupo da cada grupo inicial (A2, B2, C2 e D2) foi submetido à aplicação de FFA (4 min), antes da escovação. Os grupos A1, B1, C1 e D1 permaneceram em água destilada. Após a remoção do FFA, todos os grupos foram armazenados em saliva artificial por 1 hora, em temperatura ambiente. Posteriormente foram submetidos a 30.000 ciclos de escovação, representando 6 meses de escovação diária. Foi utilizada escova dental macia (Ultra) e uma solução de creme dental (Colgate Máxima Proteção Anticáries) e água destilada na proporção de 1:2. Ao fim do ensaio, os CP foram lavados em água corrente por 5 minutos, secos com papel absorvente, pesados novamente para obtenção da massa final e submetidos à análise da rugosidade superficial final. O desgaste de cada CP foi avaliado através da perda de massa, que foi calculada pela diferença das pesagens antes e após a escovação e a alteração da rugosidade superficial foi calculada pela diferença entre os valores das médias de rugosidade superficial inicial e final. Algumas amostras foram analisadas em microscópio de força atômica com finalidade ilustrativa. Os dados obtidos foram tratados estatisticamente. Na análise da alteração de massa, quando comparado os grupos isoladamente, somente o grupo D1(FIL) não sofreu alteração de massa significativa. As comparações entre as médias de alteração de massa dos grupos que receberam e que não receberam FFA revelaram não existir diferenças significativas entre todas as comparações. Com relação aos grupos que não receberam FFA, houve diferença significativa somente nas comparações: A1(CONT)xB1(FFY) e B1(FFY)xD1(FIL). Para os grupos que receberam FFA, não houve diferença significativa entre as médias de alteração de massa. Na análise da alteração de rugosidade superficial, quando comparado os grupos isoladamente, houve aumento significativo de rugosidade superficial nos grupos A2(FFA), B2(FFY+FFA), C1(BIS) e C2(BIS+FFA). As comparações entre as médias de alteração de rugosidade superficial dos grupos que receberam e que não receberam FFA revelaram não existir diferenças significativas entre todas as comparações. Com relação aos grupos que não receberam FFA, houve diferença significativa apenas na comparação: C1(BIS)xD1(FIL). Para os grupos que receberam FFA, as comparações A2(FFA)xD2(FIL+FFA); B2(FFY+FFA)xD2(FIL+FFA); C2(BIS+FFA)xD2(FIL+FFA) mostraram diferenças significativas. Não foi observada correlação estatisticamente significante entre a alteração de massa e rugosidade superficial entre os grupos analisados. Com base nos resultados obtidos e na análise estatística realizada, pôde-se concluir que a aplicação de FFA e a aplicação de selantes de superfície não tiveram influência na alteração de massa e na rugosidade superficial dos materiais testados. O selante de superfície Fortify não protegeu o compósito após escovação, apresentando uma maior perda de massa no grupo B1 (Fortify) em comparação com o grupo A1 (controle). Os demais selantes testados protegeram o compósito. Não existiu correlação significativa entre perda de massa e alteração da rugosidade.
The aim of this study was to assess the degradation of a composite after simulated toothbrushing cycles, with or no applying surface sealants and with or no topical application of acidulated phosphate fluoride (APF). The assessment was made by analysis of change of weight and of surface roughness. Eighty specimens were made with the Z250 composite (3M) (8 mm x 3 mm) and divided in 4 groups. All the groups have their surfaces regularized with sandpapers 1.200 under water. The group A (control) have not seal, in the group B was applied the surface sealant Fortify (Bisco), in the group C the BisCover (Bisco), and in the group D the Fill Glaze (Vigodent). Following, the specimens were stored in distilled water for 7 days at room temperature and, subsequently, they were weighted in analytical scales for obtaining initial weight and subjected to analysis of initial surface roughness using the Surftest SJ 2001 P Mitutoyo profilometer of surface roughness. The groups A, B, C and D were subdivided in 2 groups each (n = 10) and a subgroup of every initial group (A2, B2, C2, D2) was subjected to application of APF (for 4 minutes) before the toothbrushing. The groups A1, B1, C1 and D1 remained in distillated water. After the removal of the APF, all the groups were stored in artificial saliva for 1 hour at room temperature. Subsequently they were subjected to 30000 cycles toothbrushing, representing 6 months of daily toothbrushing. The soft toothbrush (Ultra) and a toothpaste (ColgateCavity Protection) and distillated water in ratio 1:2 were used. At final of assay, the specimens were washed in running water for 5 minutes, dried with absorbent paper, measured again in order to obtain the final weight, and they were subjected to analysis of final surface roughness. The wear of each specimen was assessed by weight loss, which was calculated by difference of measuring before and after toothbrushing, and the change of surface roughness was calculated by difference between the values of initial and final surface roughness. Some samples were analysed in atomic force microscope with illustrative purpose. The data were treated statistically. In the analysis of weight change, when compared to groups separately, only the group D1 (FIL) have no significant weight change. The comparisons between the means of weight change of groups with or no APF showed there are no significant differences between all the comparisons: A1 (CONT) X B1 (FFY) and B1 (FFY) x D1 (FIL). For the groups with APF, there are no significant differences between the means of weight change. In the analysis of surface roughness change, when compared to groups separately, there was a significant increase of surface roughness in groups A2 (APF), B2 (FFY + APF), C1 (BIS) and C2 (BIS + APF). The comparisons between the means of surface roughness change of the groups with and no APF revealed there no differences significant between all of comparisons. For the groups with no APF, there was significant difference only in comparison C1 (BIS) x D1 (FIL). For the groups with APF, the comparisons A2 (APF) x D2 (FIL + APF), B2 (FFY + APF) x D2 (FIL + APF), C2 (BIS + APF) x D2 (FIL + APF) showed significant differences. It wasnt noted correlation significant statistically between weight change and surface roughness between the groups analyzed. With basis on findings obtained and in the statistical analysis accomplished, it could to conclude that the application of APF and the use of surface sealants have not influence on the weight change and surface roughness of composite tested. The surface sealant Fortfy have not protected the composite after toothbrushing, showing the higher weight loss in the group B1 (Fortfy) when compared to group A1 (control). The remainder sealants tested has protected the composite. There wasnt significant correlation between weight loss and roughness change.
Gautreau, Thierry. "Estimation des pertes fer dans les machines électriques : modèles d'hysteresis Loss Surface et application aux machines synchrones à aimants". Grenoble INPG, 2005. http://www.theses.fr/2005INPG0167.
Texto completo da fonteFollowing European directives inciting electrical motors manufacturers to replace engines with poor efficiency in the near future, a high efficiency motor design policy was committed. However, the preliminary evaluation, in Finite Element Method (FEM) simulation, of the efficiency, and in particular the iron losses in the machine remains a difficult problem nowadays. An iron losses a posteriori calculation module, named " Loss Surface ", for the finite element software Flux2DTM has been developed since several years. This work proposes several improvements of LS dynamical model. A new magnetic characterization by perform inverter has permitted to increase the frequency data for the dynamical surface LS. A new formulation of dynamic contribution identification has also been achieved. Finally, the gains are consistent. Two different synchronous permanent magnet motors have been tested to evaluate the LS improvements on complex structures. The first machine is used to test the effect of induction level on iron losses evolution and the second, the frequency impact. Two physical phenomenon are as weil as studied in order to know theirs contributions on magnetic losses : the eddy-current distribution in the magnet bulk, and the influence of punching stress on magnetic mate rial proprieties
Karlsson, Linda. "Transmission Electron Microscopy of 2D Materials : Structure and Surface Properties". Doctoral thesis, Linköpings universitet, Tunnfilmsfysik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-127526.
Texto completo da fonteAbdelhameed, Elbana Maha. "Comparison between surface and subsurface drip irrigation systems using effluents". Doctoral thesis, Universitat de Lleida, 2011. http://hdl.handle.net/10803/51585.
Texto completo da fonteLos sistemas de riego por goteo se consideran como un método apropiado para la reutilización de aguas regeneradas, ya que disminuyen los riesgos sanitarios. Sin embargo, el problema más importante en la aplicación de los efluentes en sistemas de riego localizado es la obturación tanto de filtros como de goteros, lo que disminuye la uniformidad de distribución del agua. El objetivo principal de esta tesis doctoral es comparar el comportamiento de un sistema de riego por goteo superficial (DI) y otro enterrado (SDI) aplicando un efluente terciario con tres frecuencias de lavado de los laterales (sin lavado, un lavado al final de cada temporada de riego y otro mensual) con dos tipos de emisores (autocompensante y no autocompensante). Otros objetivos fueron investigar la influencia de la calidad del efluente en el proceso de filtración y calcular la pérdida de carga y la duración de los ciclos de filtración en filtro de arena mediante el análisis dimensional. Los resultados demostraron que la duración del ciclo de filtración dependió principalmente de la calidad del efluente aplicado y del diámetro efectivo de la arena utilizada. También se constató que la eficacia del proceso de filtración fue debida al diámetro efectivo de la arena del filtro, pues cuanto menor era el diámetro efectivo de la arena utilizada, más eficaz fue la filtración. El análisis dimensional ayudó a desarrollar un modelo matemático para describir la pérdida de carga en el filtro con un alto coeficiente de determinación ajustado y una buena distribución de los residuos. Además, se encontró que el caudal del lateral dependió significativamente del tipo del gotero, sistema de riego, temporada de riego y la frecuencia del lavado. En el sistema de DI, el caudal del emisor no autocompensante se incrementó significativamente durante el experimento debido a un deterioro del gotero y se disminuyó significativamente por culpa de la elevada porcentaje de los emisores obturados. El caudal del gotero autocompensante aumentó durante el experimento en los sistemas de DI y SDI. También se observó que la causa principal de la obturación del emisor en el sistema de DI fue el desarrollo de un biofilm, mientras que el de SDI se correspondió a una combinación de factores biológicos y físicos. Sin embargo, se encontró que lavar los laterales una sola vez al final de cada temporada de riego fue la mejor opción de manejo para lograr la mayor eficiencia de distribución del agua después de 1620 h de riego tanto en el sistema de riego por goteo superficial como en el enterrado.
Microirrigation is considered as an appropriate method for reclaimed wastewater reuse because it diminishes the health risks. However, the most important problem when applying reclaimed effluents in microirrigation systems is emitter and filter clogging, which lead to low system distribution uniformity. The main target of this PhD dissertation is to compare the performance of a surface (DI) and a subsurface (SDI) drip irrigation systems when applying a tertiary treated effluent under three flushing frequency (no flushing, seasonal flushing and monthly flushing) using two emitter types (pressure and non-pressure compensating). In addition, the study aimed to investigate the influence of effluent quality on the sand filtration process. Another purpose was to compute head loss across the sand media filter and time between backwashing in a sand filter media through dimensional analysis. The results revealed that sand filtration cycle duration depended mainly on the applied effluent quality and sand filter effective diameter. It was also found that the effectiveness of filtration process was significantly due to sand effective diameter, being the smaller the effective diameter the more effective the filtration process. The dimensional analysis helped to develop a mathematical model to calculate head loss across sand filter with a high adjusted coefficient of determination and a good distribution of residuals. Besides, it was found that lateral flow rates depended significantly on emitter type, irrigation system, irrigation season and flushing frequency. In DI system, lateral flow of the non-pressure compensating emitter was significantly increased throughout the experimental time due to emitter failure and significantly decreased in SDI one due to the elevated percentage of clogged emitters. The pressure compensating emitter lateral flow was increased during the experiment for DI and SDI systems. The study, as well, showed that emitter clogging in DI system was primarily due to biological factors and in the SDI one was due to a combination of biological and physical factors. However, it was found that the seasonal flushing frequency was the best management practice for achieving the highest system distribution uniformity after 1620 h of irrigation for both DI and SDI systems.
Andrews, Aaron A. "Phosphorus loss with surface runoff as affected by bioenergy-based residue and nutrient management systems for an Iowa loam soil". [Ames, Iowa : Iowa State University], 2010. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1475914.
Texto completo da fonteMikula, Léopold. "Contribution à la Modélisation des pertes dans les matériaux magnétiques de dispositifs électromécaniques : Extension vectorielle du Modèle LS et intégration en résolution éléments finis". Electronic Thesis or Diss., Université Grenoble Alpes, 2024. http://www.theses.fr/2024GRALT052.
Texto completo da fonteIn order to increase the performance of rotating machines, design software must be refined to provide better estimates of the losses generated. The aim of this study is therefore to improve 2D soft magnetic material models. So-called 'a priori' and 'a posteriori' approaches (Preisach, loss surface) will be evaluated and compared, based on experimentation and simulation. The loss surface model has been vectorized to take into account dynamic hysteresis phenomena in finite element resolution
Rauthan, Kanishk. "Investigation of surface textures on thermal and pressure drop performance of plate-fin heat exchangers". Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2022. https://ro.ecu.edu.au/theses/2597.
Texto completo da fontePourrahimi, Amir Masoud. "The synthesis, surface modification and use of metal-oxide nanoparticles in polyethylene for ultra-low transmission-loss HVDC cable insulation materials". Doctoral thesis, KTH, Polymera material, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-190808.
Texto completo da fontePolyetenkompositer med mycket låga halter av ZnO och MgO metalloxid nanopartiklar är en växande kategori material för användning som isolering av extruderade kablar avsedda för likriktad högspänning. En utmaning i utvecklingen av dessa material kan relateras till den praktiska kompositframställningen, vilken innefattar framställning av högrena metalloxid nanopartiklar som ytmodifieras med hydrofoba molekylstrukturer för att möjliggöra blandning med den hydrofoba polyetenplasten. Denna avhandling behandlar olika metoder för att framställa denna generation av isoleringsmaterial. Vid syntesen av de rena nanopartiklarna krävdes optimering av ett antal olika reaktionsparametrar för att uppnå tillfredställande slutresultat i form av partikelstorlekar och partikelmorfologier. Dessa inkluderade val av zinksalt, zinksaltkoncentration vid utfällning, samt reaktionstemperatur vid framställningen. Experimenten avslöjade att olika partikelstorlekar och partikelmorfologier kunde framställas som endast korrelerat mot källan av zinkjonerna, och berodde av vilka motjoner som zinkatomerna haft i zinksaltet (acetat, nitrat, klorid eller sulfat). Optimering av reaktionstemperaturen visade att ca 60 °C utgjorde en lämplig start för utvärdering av synteserna, som resulterade i olika partikelmorfologier i form av pyramidformade nanopartiklar till blomformationer. Utöver de specifika reaktionsparametrarna utvecklades även en ny ultrasonikeringsmetod för att rena ytorna hos partiklarna från motjoner relaterade till de valda specifika salterna. Metodiken som visade sig avsevärt mer effektiv än sedvanlig rening att utfällda nanopartiklar via repetitivt vattenutbyte, och skapade förutsättningar etablering av kolloidal stabilitet och fragmentering av aggregat i vattensuspensionerna. Efter ultrasonikeringsreningen beräknades de kvarvarande zinkhydroxidsalterna (ZHS) utgöra endast ett atomlager ZHS utifrån termogravimetriska data kompletterade med infraröd spektroskopi. En metod att eliminera de kvarvarande ZHS-komplexen från ytan av partiklarna tillämpades/utvecklades, inkluderade ytbeläggning av partiklarna med silan, följt av värmebehandling samt etsning av den resulterande kiseloxidytan, för att uppnå en ren hydroxylyta på partiklarna. Ytkemin hos dessa partiklar modifierades från att bestå av hydroxylgrupper till att utgöras av hydrofoba alkylgrupper med olika längder relaterade metyltrimetoxysilan (C1), oktyltrietoxysilan (C8), eller oktadekyltrimetoxysilan (C18). Även MgO nanopartiklar framställdes via vattenutfällning av Mg(OH)2 partiklar, vilka omvandlades till MgO nanopartiklar via en lågtemperatur värmebehandling vid 400°C. Ytan av dessa partiklar omvandlades dock till hydroxid i fuktig miljö. En ny metod att bibehålla den stora ytarean av MgO nanopartiklarna med anmärkningsvärd motståndskraft mot att omvandlas till hydroxid utvecklades således. Metoden består av (a) en låg temperatur omvandling av Mg(OH)2, (b) en kiseloxidytbehandling av nanopartiklarna för att undvika partikelsintring vid högre temperaturer och (c) en hög temperaturbehandling vid 1000 °C. De framställda partiklarna uppvisade ingen anmärkningsvärd känslighet mot luftfuktighet och bibehöll MgO sammansättningen efter exponering mot fukt. De modifierade metalloxid nanopartiklarna visade mycket liten adsorption av fenoliska antioxidanter, vilket medförde en långtidsstabilitet hos polyeten nanokompositerna. De ytmodifierade metalloxidpartiklarna visade även förbättrade möjligheter för dispergering och yt-kompatibilitet med/i polyetenmatrisen i jämförelse med omodifierade metalloxidpartiklar, utifrån mätningar baserade på dragprovning och svepelektronmikroskopi. Slutligen, de utvecklade ytorna på de modifierade nanopartiklarna skapade ett polymer/nanopartikel gränssnitt som kunder fungera som laddningsansamlingsområden i nanokompositerna, vilket resulterade i en storleksordning minskad ledningsförmåga hos kompositerna jämfört med den rena polyetenen.
QC 20160829
Bhatta, Rudra Prasad. "Electron Spectroscopic Study of Indium Nitride Layers". Digital Archive @ GSU, 2008. http://digitalarchive.gsu.edu/phy_astr_diss/23.
Texto completo da fonteKammler, Marvin. "MD simulations of atomic hydrogen scattering from zero band-gap materials". Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2019. http://hdl.handle.net/21.11130/00-1735-0000-0003-C17A-A.
Texto completo da fonteCariou, Arnaud. "Contribution à la caractérisation et la modélisation des matériaux magnétiques doux pour les machines électriques en associant les modèles Play et Loss Surface (LS)". Thesis, Université Grenoble Alpes, 2021. http://www.theses.fr/2021GRALT002.
Texto completo da fonteThis thesis aims to develop a valid iron loss model for frequency from DC to 2kHz for complex flux density waveforms in one dimension, then extending it in two dimensions. A study about the impact of temperature over the magnetic hysteresis will be conducted
Chernos, Matthew. "The relative importance of calving and surface ablation at a lacustrine terminating glacier : a detailed assessment of ice loss at Bridge Glacier, British Columbia". Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/50182.
Texto completo da fonteArts, Faculty of
Geography, Department of
Graduate
Bobe, Bedadi Woreka. "Evaluation of soil erosion in the Harerge region of Ethiopia using soil loss models, rainfall simulation and field trials". Thesis, University of Pretoria, 2004. http://hdl.handle.net/2263/26929.
Texto completo da fonteThesis (PhD (Soil Science))--University of Pretoria, 2004.
Plant Production and Soil Science
unrestricted
Andersson, Martin. "Churning losses and efficiency in gearboxes". Licentiate thesis, KTH, Tribologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-152914.
Texto completo da fonteQC 20141006
Padilla, Scott T. "Novel Transducer Calibration and Simulation Verification of Polydimethylsiloxane (PDMS) Channels on Acoustic Microfluidic Devices". Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/6922.
Texto completo da fonteBlauth, David. "Streifende Streuung schneller Atome an Oberflächen von Metalloxid-Kristallen und ultradünnen Filmen". Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2010. http://dx.doi.org/10.18452/16106.
Texto completo da fonteIn the framework of the present dissertation the interactions of fast atoms with surfaces of bulk oxides, metals and thin films on metals were studied. The experiments were performed in the regime of grazing incidence of atoms with energies of some keV. The advantage of this scattering geometry is the high surface sensibility and thus the possibility to determine the crystallographic and electronic characteristics of the topmost surface layer. In addition to these experiments, the energy loss and the electron emission induced by scattered projectiles was investigated. The energy for electron emission and exciton excitation on Alumina/NiAl(110) and SiO2/Mo(112) are determined. By detection of the number of projectile induced emitted electrons as function of azimuthal angle for the rotation of the target surface, the geometrical structure of atoms forming the topmost layer of different adsorbate films on metal surfaces where determined via ion beam triangulation.