Tesis sobre el tema "Scalene"
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Saboisky, Julian Peter Clinical School Prince of Wales Hospital Faculty of Medicine UNSW. "Neural drive to human respiratory muscles". Publisher:University of New South Wales. Clinical School - Prince of Wales Hospital, 2008. http://handle.unsw.edu.au/1959.4/42792.
Texto completoPokorny, Andrew. "Chord-Specific Scalar Material in Classical Music: An Adaptation of Jazz Chord-Scale Theory". Thesis, University of Oregon, 2014. http://hdl.handle.net/1794/18443.
Texto completo2016-09-29
Carapezzi, Stefania <1970>. "Scaled down physical properties of semiconductor nanowires for nanoelectronics scaling up". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amsdottorato.unibo.it/6222/.
Texto completoLewis, Gregory. "The scale invariant generator technique and scaling anisotropy in geophysics /". Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=68198.
Texto completoUsing a two-dimensional representation of the linear approximation to GSI, a new, greatly improved, technique for quantifying anisotropic scale invariance in geophysical fields is developed: the Scale Invariant Generator technique (SIG).
The ability of the technique to yield valid estimates is tested by performing the analysis on multifractal (scale invariant) simulations. It was found that SIG yields reasonable estimates for fields with a diversity of anisotropic and statistical characteristics. The analysis is also performed on three satellite cloud radiances and three sea ice SAR reflectivities to test the applicability of the technique. SIG also produced reasonable estimates in these cases.
Gartenburg, Michael A. "Scale and TDOA estimation using signal heterodyning and wavelet scaling". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0005/MQ44842.pdf.
Texto completoRossmanith, Eva, Niels Blaum, Manfred Keil, F. Langerwisch, Jork Meyer, Alexander Popp, Michael Schmidt et al. "Scaling up local population dynamics to regional scales : an integrated approach : [Poster]". Universität Potsdam, 2006. http://www.uni-potsdam.de/imaf/events/ge_work0602.html.
Texto completoInterdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung
Workshop vom 9. - 10. Februar 2006.
Mohammed, Abdulwasey. "Scaling up of peatland methane emission hotspots from small to large scales". Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/15772.
Texto completoMiller, W. B. "Localization of Reserve Remobilization During Scalet Formation on Lilium longiflorum Scales". College of Agriculture, University of Arizona (Tucson, AZ), 1988. http://hdl.handle.net/10150/216050.
Texto completoChristidis, Konstantinos. "Characterisation and monitoring of mineral deposits in down-hole petroleum pipelines". Thesis, Robert Gordon University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325400.
Texto completoDas, Narendra Narayan. "Modeling and application of soil moisture at varying spatial scales with parameter scaling". [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2877.
Texto completoPenmetsa, Sita rama raju S. "SCALE MODELING OF ALUMINUM MELTING FURNACE". UKnowledge, 2004. http://uknowledge.uky.edu/gradschool_theses/331.
Texto completoMazzariol, Leonardo Monteiro. "Representação de estruturas sujeitas à cargas de impacto através de modelos escalonados: estrutura e modelo feitos de materiais diferentes". Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/3/3151/tde-18042017-135251/.
Texto completoIt is hypothesized that it is possible to reproduce the behaviour of the prototype by using models made of different materials. The influence of thickness, different densities, flow stresses, hardening and viscoplasticity are all evaluated through analytical equations and simulations of basic structures such as beam, plate and the impact of a double plate structure. In addition, quasi-static and dynamic materials characterization are conducted , with experiments being performed in circular plates for three different scales (1/1, 2/3 and 1/3), four materials (Aluminum, Titanium, Stainless Steel and Copper) and two conditions impact of a mass (3,5m/s) and a projectile at high speed (130m/s). It is shown that the use of Johnson-Cook\'s law to describe the viscoplastic behavior of the materials allows a satisfactory approximation to the calculation of the corrected impact velocity, without the need for additional information on the behavior of the structure. In addition, the results reveal the relevance of maintaining the ratio between impact mass and structure mass constant in model and prototype, leading to the desirable similarity of the distortions between the two. Thus, when confirming the hypothesis of this work, it is possible to infer the behavior of a prototype using small scale models made from different materials.
Teh, Tong H. "A novel electrochemical technique for mineral scale coverage and scaling tendency quantification". Thesis, Heriot-Watt University, 2011. http://hdl.handle.net/10399/2488.
Texto completoPerera, Ashansa. "Window-based Cost-effective Auto-scaling Solution with Optimized Scale-in Strategy". Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-194210.
Texto completoGoodloe, John Bennett. "STANDARDIZED SUB-SCALE DYNAMOMETER SCALING METHOD FOR TRANSIT AND FREIGHT TRAIN APPLICATIONS". OpenSIUC, 2016. https://opensiuc.lib.siu.edu/theses/1899.
Texto completoSanderson, Philip John 1974. "Experimental verification of the simplified scaling laws for bubbling fluidized beds at large scales". Monash University, Dept. of Chemical Engineering, 2002. http://arrow.monash.edu.au/hdl/1959.1/7891.
Texto completoTopczewski, Anna Marie. "Effect of Violating Unidimensional Item Response Theory Vertical Scaling Assumptions on Developmental Score Scales". Diss., University of Iowa, 2013. https://ir.uiowa.edu/etd/4921.
Texto completoWesthoff, Andreas. "Spatial Scaling of Large-Scale Circulations and Heat Transport in Turbulent Mixed Convection". Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2012. http://hdl.handle.net/11858/00-1735-0000-000D-FD19-2.
Texto completoSoumagnac, M. T. "Tipping scales in galaxy surveys : star/galaxy separation and scale-dependent bias". Thesis, University College London (University of London), 2015. http://discovery.ucl.ac.uk/1460581/.
Texto completoKia, Seyed Hossein. "Uncertainty associated with scaling spectral indices of carbon fluxes at various spatial and temporal scales". Thesis, University of Southampton, 2017. https://eprints.soton.ac.uk/417789/.
Texto completoSloan, William Taylor. "Up-scaling hydrological processes and the development of a large-scale river basin modelling system". Thesis, University of Newcastle Upon Tyne, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299643.
Texto completoPadilla, Sonya E. "Relationship of MMPI-2-RC Demoralization scale to MCMI-III scales in psychiatric inpatients". Diss., Wichita State University, 2010. http://hdl.handle.net/10057/3466.
Texto completoThesis (Ph.D.)--Wichita State University, College of Liberal Arts and Sciences, Dept. of Psychology
Chang, Patrick. "An improved size, matching, and scaling synthesis method for the design of meso-scale truss structures". Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/41138.
Texto completoYuan, Mingdong. "Prediction of sulphate scaling tendency and investigation of barium and strontium sulphate solid solution scale formation". Thesis, Heriot-Watt University, 1989. http://hdl.handle.net/10399/912.
Texto completoMagalhães, Adsson. "Três estudos usando a Escala centiMax de Borg® (Escala CR de Borg®, CR 100, cM) para o escalonamento de sintomas depressivos". Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/47/47132/tde-13122017-093536/.
Texto completoThinking about the millions of people who are affected worldwide by depressive disorders (322 million, more than 11 million in Brazil and almost 450.000 in Sweden), we tried to create an instrument to assess depression more effectively. In general, depressive disorders are characterized by sadness, loss of interest/pleasure, feelings of guilt or low self-esteem, changes in sleep and appetite, tiredness, and low concentration. In addition to the diagnostic criteria, several instruments evaluate depressive disorders. We used the Beck Depression Inventory to validate the Borg CR100 ScaleR for scaling depressive symptoms. The Borg ScalesR were developed in the 60\'s for the evaluation of perceived exertion. The CR100 is a scale from 0 to 100, with verbal categories placed in agreement with the numerical scale so as to obtain ratio data. This type of scale has several advantages, such as allowing comparison between and within subjects and groups, creating symptoms profile, analyzing individual symptoms and the intensity ratio between them. This thesis consists of three papers using the CR100. Study #1 investigated the properties of CR100 compared to BDI. Fifty Swedish students of Psychology answered an online questionnaire and the results pointed a high correlation between the two scales (r = 0.754, p <0.001), demonstrating that the Borg Scale evaluates depression as well as the BDI, providing more results though. The symptom profile generated was much more detailed than the BDI, in addition, the data was more accurate and not that sensitive to mathematical transformations. Study #2 looked after the validation of CR100 for Brazilian Portuguese and, like #1, the application in 50 Brazilian students. The results also pointed to the high correlation between the scales (r = 0.824, p <0.001) with all characteristics preserved in both nationalities. The first reliability analysis revealed a high alpha value (between 0.952 and 0.947) and R2 (between 0.778 and 0.976), higher than the BDI. The aim of Study #3 was to investigate the psychometric properties of CR100 in depressive (N = 25) and healthy participants (N = 25), and to find cutoff points for light, medium and severe depression. The reliability analysis of the Scale revealed an alpha of 0.954 and by running a factorial reduction, - 12 - the 32 items were grouped into seven components. It was also possible to construct a profile of symptoms between the two populations verifying the sensitivity of CR100 to differentiate healthy from depressive population, in a 95% confidence interval. An index of the ratio between patients and healthy subjects could be created, generating a mini scale with eight items with an alpha value of 0.80 and correlation with the full scale of r = 0.915 (p <0.001) and with the BDI of r = 0.820 (p <0.001). The three studies have shown satisfactory results that match with what has already been demonstrated by researches with the Borg ScalesR. It has also been presented the possibility of using the CR100 to assess depressive symptoms with more information and which data are more accurate than the instruments analyzed
Chen, Chih-Chieh. "Transient mountain waves in an evolving synoptic-scale flow and their interaction with large scales /". Thesis, Connect to this title online; UW restricted, 2005. http://hdl.handle.net/1773/10078.
Texto completoLiu, Dan. "Research on Performance Evaluation and Anti-scaling Mechanism of Green Scale Inhibitors by Static and Dynamic Methods". Paris, ENSAM, 2011. http://www.theses.fr/2011ENAM0025.
Texto completoLes exigences environnementales imposent de nombreux défis dans le domaine du traitement des eaux. Ainsi, le concept de " chimie verte " a-t-il été proposé et l'utilisation des produits chimiques " écologiques " est devenue une nécessité. Il est donc d'une importance primordiale d'élaborer des inhibiteurs d'entartrage " verts " afin de combattre les phénomènes d'entartrage qui ont des conséquences désastreuses, voire catastrophiques, dans certaines installations industrielles, comme les circuits de refroidissement des centrales nucléaires. Dans cette étude, l'efficacité de différents inhibiteurs d'entartrage de CaCO3 a été évaluée dans un circuit de refroidissement simulé. En tant qu'inhibiteurs de précipitation de Ca-phosphonates, des homo-, co- et ter-polymères ont également été étudiés en matière de leur efficacité. En fait, l'ajout de ces polymères dans l'eau contenant des phosphonates peut réduire la précipitation du Ca-phosphonates et renforcer l'efficacité d'inhibition de l'entartrage du CaCO3. L'effet synergétique de l'acide polyaspartique (PASP) et de l'acide polyepoxysuccinique (PESA) sur l'inhibition de l'entartrage a été étudié en utilisant à la fois des méthodes statique et dynamique. Les résultats obtenus montrent que l'efficacité inhibitrice du mélange PASP-PESA est supérieure à celle du PASP ou du PESA pris individuellement pour la précipitation de CaCO3, CaSO4 et BaSO4. L'effet de la concentration des inhibiteurs, de la température et de la concentration de Ca2+ ont également été étudié. Par ailleurs, l'analyse par MEB a bien montré la modification de morphologie des précipités en présence du PASP et du PESA. Dans ce travail, on a également étudié les propriétés inhibitrices des ions Cu2+ et Zn2+ dans l'eau potable avec la méthode de Précipitation Contrôlée Rapide (PCR) développée dans le Laboratoire (LIM). Les résultats obtenus montrent que ces ions métalliques sont des inhibiteurs très efficaces à faible concentration. De plus, l'analyse par MEB et IR indiquent que les ces ions peuvent affecter la morphologie cristalline du CaCO3. Par ailleurs, l'influence de la température et du CO2 dissous sur le pouvoir entartrant de l'eau minérale de Salvetat (utilisée comme eau de référence), en présence des ions Cu2+ et Zn2+, a été étudiée expérimentalement. L'inhibiteur idéal serait un composé sous forme solide dont la solubilité serait très faible, mais largement suffisante pour assurer une inhibition totale de l'entartrage. Il pourrait ainsi être mis en contact directement avec l'eau à traiter sans que l'on ait à se soucier de sa concentration qui serait régulée automatiquement par sa solubilité. La synthèse de tels inhibiteurs a été réalisée et leur efficacité a été évaluée durant cette thèse. En fait, les inhibiteurs solides obtenus ont une solubilité de l'ordre de 1,5 mg/L dans l'eau du robinet de Paris et ils donnent une inhibition totale de CaCO3 dans la même eau avec une concentration seulement de 30 ppb (μg/L). De plus, l'introduction de ces inhibiteurs solides peut être réalisée facilement par une cartouche
Okrah, Maxwell. "Decentralised planning and 'scales' of participation : an analysis of multi-scale bottom-up planning in Ghana". Thesis, University of Reading, 2018. http://centaur.reading.ac.uk/80305/.
Texto completoGraham, Tabitha. "INVESTIGATION OF MEDIA INGREDIENTS AND WATER SOURCES FOR ALGAE CO2 CAPTURE AT DIFFERENT SCALES TO DEMONSTRATE THE CORRELATIONS BETWEEN LAB-SCALE AND LARGE-SCALE GROWTH". UKnowledge, 2013. http://uknowledge.uky.edu/bae_etds/16.
Texto completoXiao, Han [Verfasser]. "Scaling of sorption isotherms to quantify the field-scale variability of heavy metal retardation in soil / Han Xiao". Hannover : Gottfried Wilhelm Leibniz Universität Hannover, 2019. http://d-nb.info/1190283409/34.
Texto completoTolle, Kathryn. "An Examination of the Criterion-Related Validity of Four Maximizing Tendency Scales: Which Scale is the "Best?"". Xavier University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=xavier1458418698.
Texto completoParker, Kimberly. "Utility of the General Validity Scale Model: Development of Validity Scales for the Co-parenting Behavior Questionnaire". VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/2301.
Texto completoMay, Adam D. R. "Identification of fire gases in early stages of fire in laboratory scaled and full scale fire experiments". Thesis, University of Central Lancashire, 2011. http://clok.uclan.ac.uk/2823/.
Texto completoRogers, Eric Paul. "Scale Construction and Halo Effect in Secondary Student Ratings of Teacher Performance". Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd910.pdf.
Texto completoScott, Erin G. "Process algebra with layers : a language for multi-scale integration modelling". Thesis, University of Stirling, 2016. http://hdl.handle.net/1893/23516.
Texto completoNeureither, Lara [Verfasser], Carsten [Gutachter] Hartmann, Tony [Gutachter] Lelièvre y Christof [Gutachter] Schütte. "Irreversible multi-scale diffusions: time scales and model reduction / Lara Neureither ; Gutachter: Carsten Hartmann, Tony Lelièvre, Christof Schütte". Cottbus : BTU Cottbus - Senftenberg, 2019. http://d-nb.info/120227546X/34.
Texto completoKotras, Nicole. "A revision of a section of the hearing and speech scale of the Griffiths Scales of Mental Development". Thesis, University of Port Elizabeth, 2004. http://hdl.handle.net/10948/350.
Texto completoZhang, Xijuan. "Improving the factor structure of psychological scales : the Expanded format as the alternative to the Likert scale format". Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/54043.
Texto completoArts, Faculty of
Psychology, Department of
Graduate
Sendrowski, Janek. "Feigenbaum Scaling". Thesis, Linnéuniversitetet, Institutionen för matematik (MA), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-96635.
Texto completoLandis, Mark J. "The effects of scale and information distribution on group decision-making processes and outcomes". Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4377.
Texto completoThe entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on month August 3, 2007) Includes bibliographical references.
Hattingh, Karien. "The validation of a rating scale for the assessment of compositions in ESL / K. Hattingh". Thesis, North-West University, 2009. http://hdl.handle.net/10394/4203.
Texto completoThesis (Ph.D. (English))--North-West University, Potchefstroom Campus, 2009.
Jordan, Benjamin Raines. "Sustainability at multiple scales: interactions between environment, economic and social indicators at the country, city and manufacturing facility scale". Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/43717.
Texto completoSvensk, Mikael. "Personlighet samt förekomst av ADHD i barndomen hos en grupp dömda sexualbrottslingar". Thesis, Stockholm University, Department of Psychology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-1109.
Texto completoVarje år anmäls ca 10 000 sexualbrott i Sverige. Forskning har visat att sexualbrottslingar är en heterogen grupp i fråga om personlighet. Studier visar dock på att de ofta har hög aggressivitet och mycket ångest, något som de får utlopp för genom sin sexualitet. Forskare har även påvisat en hög förekomst av Attention Deficit Hyperactivity Disorder (ADHD) i barndomen hos sexualbrottslingar. Syftet med föreliggande undersökning var att undersöka förekomst av ADHD i barndomen, personlighet och samband mellan ADHD och personlighet hos dömda sexualbrottslingar (N = 30). Undersökningen syftade även till att undersöka uppväxt- och brottsbelatsning hos sexualbrottslingar. Resultaten visade att undersökningsdeltagarna i huvudsak inte skiljde sig från normalpopulationen i personlighet. Resultaten visade även att 30% av undersökningsdeltagarna hade ADHD i barndomen. Vidare visar resultaten att det råder samvarians mellan förekomsten av ADHD i barndomen, uppväxtbelastning och brottsbelastning. Detta är i linje med tidigare forskning som funnit en överrepresentation av ADHD bland kriminella.
Tarlevé, Brigitte. "Le syndrome de la traversée cervico-thoraco-brachiale : à propos de vingt-cinq observations de consultation neurologique de ville". Nantes, 1986. http://www.theses.fr/1986NANT3527.
Texto completoBorg, Elisabet. "On Perceived Exertion and its Measurement". Doctoral thesis, Stockholm : Department of Psychology, Stockholm University, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-6862.
Texto completoSpencer, Katherine G. "Development and validation of the Comfort and Conformity of Gender Expression Scale (CAGES)". Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/4826.
Texto completoThe entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on February 29, 2008) Vita. Includes bibliographical references.
Bridge, S. R. J. "The landscape scale spatial distribution of vegetation gradients in a mixedwood boreal forest, linking ecological patterns to geomorphic processes across scales". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq20820.pdf.
Texto completoWimmer, Christian L. "Assessing item and scale sensitivity to therapeutic change on the College Adjustment Scales : working toward a counseling center specific outcome questionnaire /". Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd2405.pdf.
Texto completoWimmer, Christian L. "Assessing Item and Scale Sensitivity to Therapeutic Change on the College Adjustment Scales: Working Toward a Counseling Center Specific Outcome Questionnaire". BYU ScholarsArchive, 2008. https://scholarsarchive.byu.edu/etd/1384.
Texto completoPérez, Ramírez Yolanda. "Contribució a l'estudi de l'efecte del canvi d'escala en l'experimentació en incendis forestals". Doctoral thesis, Universitat Politècnica de Catalunya, 2010. http://hdl.handle.net/10803/6484.
Texto completoDavant d'aquesta situació, en les darreres dècades s'ha impulsat fortament la recerca en l'àmbit dels incendis forestals. Tanmateix, l'estudi dels incendis forestals és certament complex per les condicions i l'entorn on aquests es desenvolupen, a banda també del gran nombre de fenòmens -físics, químics i socials- que interaccionen al llarg de diferents escales espacials i temporals, per a donar lloc a l'inici i propagació del foc. És per això que bona part de la recerca sobre el comportament dels incendis forestals ha tingut lloc bàsicament al laboratori, tot i que qüestions com ara com traslladar aquests resultats experimentals als incendis reals, o bé fins a quin punt aquest tipus d'experimentació és útil o què és el que realment es pot extrapolar i què no, no han tingut encara cap resposta clara.
L'objectiu d'aquesta tesi ha estat doncs el de contribuir a l'estudi del canvi d'escala en l'experimentació en incendis forestals pel què fa al comportament del foc, mitjançant les tècniques de l'anàlisi dimensional i de semblança. En primer lloc s'ha realitzat una extensa revisió bibliogràfica centrada bàsicament en aquells treballs que havien aplicat d'alguna manera o altra l'anàlisi dimensional i de semblança a l'estudi dels incendis i en particular dels incendis forestals. S'ha vist que no es possible realitzar un escalatge complet d'aquest fenomen i que el més utilitzat ha estat l'escalatge de Froude. A més s'ha detectat que mai abans s'ha aplicat aquest tipus d'anàlisi als models que s'utilitzen normalment avui dia en l'experimentació de laboratori. A continuació s'ha fet doncs una anàlisi exhaustiva de totes les variables que determinen el comportament d'un incendi forestal en els diferents escenaris experimentals (de laboratori i de camp). A partir d'aquestes variables s'ha realitzat una anàlisi dimensional per a estudiar la propagació d'un front de flames -tan bàsic com en condicions de vent i pendent- així com una anàlisi de semblança que ha permès obtenir les lleis d'escala per a les diferents variables que caracteritzen la propagació d'un incendi forestal. S'ha dissenyat i executat un programa experimental al laboratori amb l'objectiu de validar si es complien les lleis d'escala trobades i de determinar-ne el rang de validesa i les possibles causes en cas que no es complissin.
Els resultats obtinguts han mostrat que per a fronts de flama bàsics propagant-se sense vent ni pendent, totes les variables analitzades segueixen les lleis d'escala derivades de l'estudi teòric, en el rang de longituds de front de flama abraçat que va dels 25 cm als 3 m. Nogensmenys cal remarcar que paràmetres com la humitat i el tipus de combustible o les característiques de la instal·lació experimental utilitzada poden alterar enormement els resultats si no es controlen adequadament. En el cas dels fronts de flama propagant pendent amunt, els resultats han mostrat que les lleis d'escala de la geometria de flama es compleixen per a tot el rang de pendents estudiat que va de 0 fins a 30°, mentre que en el cas de la llei d'escala de la velocitat de propagació deixa de complir-se per a pendents de 30°. Finalment, en el cas dels fronts de flama propagant en condicions de vent, els resultats han mostrat que per a velocitats del vent superiors a aproximadament 2,5 m/s les lleis d'escala tant de la velocitat de propagació com de la geometria de flama deixen de complir-se.
Al final d'aquest treball s'apunten les causes que poden conduir a l'incompliment de les lleis d'escala així com als factors que poden restar validesa als experiments efectuats a escala de laboratori, quan es vol extrapolar els resultats a escales més grans o fins i tot a incendis reals.
Year after year millions of hectares are destroyed by wildland fires, not only in Europe but all over the world; just remember the dramatic episodes recently occurred in California or Australia. Besides the evident environmental impact caused by these fires -emission of greenhouse gases, biodiversity loss, soil erosion, etc- wildland fires represent also a social problem of primary order that threatens human life and their assets.
Because of this situation, during the last decades research on wildland fires has been greatly boosted. Nevertheless, the study of forest fires is really complex due to the conditions and the environment in which they develop and to the number of phenomena -physical, chemical and social- that interact all along the different spatial and temporal scales that give rise to the start and development of a fire. That is partly the reason because the study of wildland fire behaviour has mainly been developed in laboratories, but questions like how these experimental results can be translated to real fires?, or is really this kind of experimentation useful?, or what can be extrapolated? These questions have not yet received a clear answer.
The goal of this work was to improve the knowledge on the effect of changing the scale in the experimental study of forest fire behaviour, by means of dimensional and similarity analysis. First an extended bibliographic review has been done, centred on those works that had applied in one or another way the dimensional and similarity analysis to the study of fires and more specifically to forest fires. It was observed that it is not possible to undergo a complete scaling of a forest fire and that the most used partial scaling technique was the Froude scaling. Moreover it was detected that this kind of analysis was never before applied to the laboratory models used currently to obtain experimental data on wildland fires. Thus, an exhaustive analysis of all the variables affecting forest fire behaviour has been carried out for the diverse experimental scenario (in the lab and field). From these variables, a complete dimensional analysis has been developed in order to study the spread of a flames front -both in basic conditions and with slop or wind- and a subsequent similarity analysis has provided the scaling laws governing all the variables under study. A complete experimental program has been designed and developed in the laboratory with the aim of validating the scaling laws previously found and to establish the possible causes of any failure of the laws.
The results obtained show that in the case of a basic flame front, spreading under no wind and no slope conditions, all the variables analysed followed the scaling laws obtained during the theoretical study for flames front lengths ranging from 25 cm to 3 m. For the tests under slop conditions, the results indicate that the scaling laws corresponding to the flame geometry are verified for all the slopes tested which range from 0 to 30°, while in the case of the rate of spread scaling law is no longer verified for the 30° slope. Finally, in the case of flame fronts spreading under wind conditions, the results show that for wind speed values greater than 2,5 m/s neither of the scaling laws corresponding to the flame geometry and the rate of spread, are verified. It has also been observed that parameters such as moisture content, the type of fuel or the specific design of the experimental device used can have a big influence on the results obtained if they are not adequately controlled.
At the end of this work, the main causes leading to the failure of the scaling laws are pointed out together with the factors that can make the laboratory experiments less reliable when trying to extrapolate the results to larger scales or even to real fires.