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Dissertations / Theses on the topic 'Surface slope'
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Dixon, Philippe. "Gait dynamics on a cross-slope walking surface." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=112616.
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Though the biomechanics of level walking have been studied extensively, the adaptations required for cross-slope locomotion are still largely unknown despite being a common terrain characteristic. The goals of this thesis were to determine (1) ground reaction forces (GRF) and moments (GRM), (2) lower-limb kinematics, and (3) lower-limb joint reaction forces (JRF) and moments (JRM) during level and cross-slope walking. Statistical analyses were made across limbs (down-slope (DS) and up-slope (US)) and across slope condition (level (0°) and cross-slope (6°)) (2X2 ANOVA). Ten healthy male volunteers performed several barefoot walking trials. The lower-limbs responded asymmetrically to the cross-slope condition by substantially changing (1) the medio-lateral GRF, (2) the sagittal and frontal plane kinematics as well as step-width, and (3) the medio-lateral JRF and frontal plane JRM. The modest cross-slope induced important asymmetrical changes in locomotor patterns and may represent a substantial physical obstacle to populations with restricted mobility.
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Kwok, Sabastein Yih Feng. "Stochastic analysis of coupled surface and subsurface flow model in steep slopes for slope stability analysis /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?CIVL%202003%20KWOK.
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Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003.<br>Includes bibliographical references (leaves 201-205). Also available in electronic version. Access restricted to campus users.
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RIVA, ENEA. "Slope inequalities for fibred surfaces and fibreed threefolds." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2022. http://hdl.handle.net/10281/374266.
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Su una varieta algebrica fibrata si definesce un invariante relativo detto slope che ne specifica la natura. Per queste fibrazioni un ruolo importante è svolto del fibrato di Hodge e dagli invarianti geometrici delle fibre generiche.
In particulare in questa tesi ci concentreremo su superfici e threefold fibrati su curve, dando un stima dal basso della slope che dipenda del rango unitario del fibrato di hodge e da:
- indice di clifford cella curva generale, nel caso di superfici;
-dal genere geometrico ($p_{g}$) della superficie generale nel caso di threefold.
infine sfrutteremo i risultati ottenuti sui threefold per definere un upper bound del rango unitario $u_{f}$ in funzione di $p_{g}$ sotto l'ipotesi che il genere della curva base sia zero o uno.<br>On a fibred algebraic variety, is defined a relative invariant called slope which classifies the variety itself. For these fibration a main character is played by the Hodge bundle and by the geometric invariants of the general fibers.
In particular in this thesis we focus on surfaces and threefolds fibred over curves, and we give a lower bound for the slope which depends on the unitary rank of the hodge bundle and on:
-the clifford index of the general curve, in case of fibred surfaces;
- the geometric genus ($p_{g}$) of the general surface, in case of threefolds.
Finally we use these results on fibred threefolds to make a new upper bound for the unitary rank $u_{f}$ depending on $p_{g}$ under the hypothesis that the genus of the base curve is zero or one.
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Staples, James Mark. "Slope scale modeling of snow surface temperature in topographically complex terrain." Thesis, Montana State University, 2008. http://etd.lib.montana.edu/etd/2008/staples/StaplesJ1208.pdf.
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In mountainous terrain, landscape can influences the thermal state of snow. Snow temperature and mass flux have been calculated using an energy balance model, Radtherm/RT, to account for the effects of topography and meteorological conditions. For a specific location, a terrain model is defined and contains a connected assemblage of elements or facets. Each element has a specified terrain type with assigned thermal properties. Meteorological data are applied, and a one dimensional energy balance is calculated for each element. This energy balance includes conduction, convection, radiation, and latent heat; however, the calculation of radiation is unique. Taking into account topography, global position, and time, the model is used to calculate incoming solar radiation for each element as well as reflected short wave radiation and the exchange of long wave radiation between terrain surfaces. Light detection and ranging topographic data with a one meter resolution were used to create separate models (on the order of 10 4 m2) for two slopes in southwest Montana. Meteorological data were collected at these two slopes as well as a third location having a relatively unobstructed view of the sky. The results for elements in different locations and under different meteorological conditions were compared. Readily available USGS topographic data with a 30 meter resolution were used to create a model (on the order of 10 6 m2) containing both slopes. For this model of a much larger scale, surface temperatures and mass flux were again calculated and compared with results for the slope scale models. Incoming long wave radiation from the atmosphere only was found to be critical input data for accurate temperature calculations. The set value for albedo also had a major effect. When suitable long wave data and good estimations of albedo were used, snow surface temperature was calculated with accuracies on the order of several degrees. Additionally, when surface hoar deposition and growth was observed and reasonable temperature results were achieved, calculated values of mass flux were consistently positive. In one instance, observed variations in surface hoar growth across a slope matched calculated variations in mass flux across the same slope.
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Tan, Ding. "Seismic slope safety : determination of critical slip surface using acceptability criteria." Thesis, Imperial College London, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.439439.
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TAKEDA, Yasuo, 泰雄 竹田, Jun KATAOKA, et al. "Slope failure in the rectilinear zone of hillsides." 名古屋大学農学部付属演習林, 1987. http://hdl.handle.net/2237/8663.
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Hardenberg, Bon J. van. "A laboratory study of slope flow induced by a surface salt flux." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26415.
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The salt expulsion caused by the freezing of seawater and the drainage of brine from the ice creates a convectively mixed layer, which extends to the bottom in shallow coastal regions. This buoyancy flux at the surface was simulated in laboratory experiments by percolating salt water through a porous membrane into a tank. Shadowgraph images show that a down-slope flow is induced when the bottom of the tank is set at an angle.
Velocity maxima in the slope flow, measured from the movement of injected dye ranged from 0.09 to 0.66 cm/s. Fluid densities were determined using thermistors and small-volume conductivity micro-cells developed for this purpose. For bottom slope angles between 2.2° and 5.5°, and at computed salt fluxes between 1.82★10⁻⁵ and 1.63★10⁻⁶ g/cm²/s, the salinity profiles showed slope flow depths between 7 and 17 mm with a rise in salinity of 0.24 to 0.92 ppt above those in the mixed layer.
Entrainment at a density interface without shear, using this experimental arrangement, agreed closely with predicted results by Bo Pedersen. Using the entrainment model for a turbulent gravity current, entrainment factors computed from the data of the slope flow experiments were up to two orders of magnitude larger than those predicted for flows in a quiescent environment.
This is contrary to visual evidence of the experiments or to Arctic field data, which indicate low rates of entrainment. This suggests that a different model is required to explain the interaction between such flows and the turbulent environment.<br>Science, Faculty of<br>Earth, Ocean and Atmospheric Sciences, Department of<br>Graduate
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Nearing, Mark A., Viktor O. Polyakov, Mary H. Nichols, et al. "Slope–velocity equilibrium and evolution of surface roughness on a stony hillslope." COPERNICUS GESELLSCHAFT MBH, 2017. http://hdl.handle.net/10150/624932.
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Slope–velocity equilibrium is hypothesized as a state that evolves naturally over time due to the interaction between overland flow and surface morphology, wherein steeper areas develop a relative increase in physical and hydraulic roughness such that flow velocity is a unique function of overland flow rate independent of slope gradient. This study tests this hypothesis under controlled conditions. Artificial rainfall was applied to 2 m by 6 m plots at 5, 12, and 20 % slope gradients. A series of simulations were made with two replications for each treatment with measurements of runoff rate, velocity, rock cover, and surface roughness. Velocities measured at the end of each experiment were a unique function of discharge rates, independent of slope gradient or rainfall intensity. Physical surface roughness was greater at steeper slopes. The data clearly showed that there was no unique hydraulic coefficient for a given slope, surface condition, or rainfall rate, with hydraulic roughness greater at steeper slopes and lower intensities. This study supports the hypothesis of slope–velocity equilibrium, implying that use of hydraulic equations, such as Chezy and Manning, in hillslope-scale runoff models is problematic because the coefficients vary with both slope and rainfall intensity.
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Albataineh, Nermeen. "SLOPE STABILITY ANALYSIS USING 2D AND 3D METHODS." University of Akron / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=akron1153719372.
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Cooperstein, Michael Stephen. "The effects of slope aspect on the formation of surface hoar and diurnally recrystalized near-surface faceted crystals." Thesis, Montana State University, 2008. http://etd.lib.montana.edu/etd/2008/cooperstein/CoopersteinM0508.pdf.
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This research was conducted to determine if slope aspect played a role in the formation, size and shape of surface hoar and near-surface faceted crystals and on the meteorological variables that are known to result in the formation of these two weak layers. No studies have specifically studied the effects of slope aspect on the size and shape of these crystals nor the effects of slope aspect on the meteorological variables which are known to result in differences in temperature and vapor pressure gradients and ultimately result in the formation of two weak layers.
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Ebel, Brian A. "Process-based characterization of near-surface hydrologic response and hydrologically driven slope instability /." May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Maldonado, Alejandro V. "High Resolution Optical Surface Metrology with the Slope Measuring Portable Optical Test System." Diss., The University of Arizona, 2014. http://hdl.handle.net/10150/337294.
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New optical designs strive to achieve extreme performance, and continually increase the complexity of prescribed optical shapes, which often require wide dynamic range and high resolution. SCOTS, or the Software Configurable Optical Test System, can measure a wide range of optical surfaces with high sensitivity using surface slope. This dissertation introduces a high resolution version of SCOTS called SPOTS, or the Slope measuring Portable Optical Test System. SPOTS improves the metrology of surface features on the order of sub-millimeter to decimeter spatial scales and nanometer to micrometer level height scales. Currently there is no optical surface metrology instrument with the same utility. SCOTS uses a computer controlled display (such as an LCD monitor) and camera to measure surface slopes over the entire surface of a mirror. SPOTS differs in that an additional lens is placed near the surface under test. A small prototype system is discussed in general, providing the support for the design of future SPOTS devices. Then the SCOTS instrument transfer function is addressed, which defines the way the system filters surface heights. Lastly, the calibration and performance of larger SPOTS device is analyzed with example measurements of the 8.4-m diameter aspheric Large Synoptic Survey Telescope's (LSST) primary mirror. In general optical systems have a transfer function, which filters data. In the case of optical imaging systems the instrument transfer function (ITF) follows the modulation transfer function (MTF), which causes a reduction of contrast as a function of increasing spatial frequency due to diffraction. In SCOTS, ITF is shown to decrease the measured height of surface features as their spatial frequency increases, and thus the SCOTS and SPOTS ITF is proportional to their camera system's MTF. Theory and simulations are supported by a SCOTS measurement of a test piece with a set of lithographically written sinusoidal surface topographies. In addition, an example of a simple inverse filtering technique is provided. The success of a small SPOTS proof of concept instrument paved the way for a new larger prototype system, which is intended to measure subaperture regions on large optical mirrors. On large optics, the prototype SPOTS is light weight and it rests on the surface being tested. One advantage of this SPOTS is stability over time in maintaining its calibration. Thus the optician can simply place SPOTS on the mirror, perform a simple alignment, collect measurement data, then pick the system up and repeat at a new location. The entire process takes approximately 5 to 10 minutes, of which 3 minutes is spent collecting data. SPOTS' simplicity of design, light weight, robustness, wide dynamic range, and high sensitivity make it a useful tool for optical shop use during the fabrication and testing process of large and small optics.
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Fell, Jessica. "An analysis of surface water from an informal settlement, Langrug, Franschhoek: down a slippery slope." Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/27894.
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Contaminated surface water from limited sanitation and drainage systems in informal settlements degrades receiving rivers. However, little is known about the water quality and flow of rivers draining informally settled catchments. This study explores the dynamics of a human water system in an informally settled catchment in the present, and then uses these insights to investigate possible trajectories in the future. The objectives are twofold: (i) to characterise the water quality and flow of a river draining an informally settled catchment in Franschhoek, South Africa, and, (ii) to investigate the hydrologic and water quality effects of future land use and climate changes in the catchment. River water samples were collected during dry days for four months and over five rainfall events. Highly elevated concentrations of NH₃-N (8.4 ± 5.2mg/L), PO₄³⁻ (5.9 ± 7.4mg/L) and TSS (135 ± 124mg/L) were recorded in the informal settlement. Correlation analyses between land use types and water quality showed significant relationships between informal settlement and NH₃-N, PO₄³⁻, DO, EC and TSS. Multiple regression models investigated six hypothetical land use changes scenarios and indicated that if informal settlement and built-up area doubled in size, there would be an increase in the concentration of NH₃-N by 83%, PO₄³⁻ by 85% and TSS by 86%. During the rainfall events multiple NH₃-N, PO₄³⁻, TSS concentration peaks were observed, with concentrations peaking at 3.5mg/L, 6.6mg/L and 1868mg/L respectively. Various significant correlations between lagged rainfall and pollutant concentrations revealed that rainfall caused an increase in NH₃-N, PO₄³⁻ and TSS after one hour, while NO₃⁻-N and DO responded to rainfall after two hours and flow after three hours. Multiple regression models explored two hypothetical climate change scenarios involving an increase in the 10 and 20 year design rainfall depth. The models demonstrated that if the rainfall depth of a 20 year rainfall event increased by 15%, there would be an increase in peak concentration of NH₃-N by 17% and PO₄³⁻ by 15%, a decrease in DO by 21%, and an increase in peak flow by 21%. The results reveal the pervasive impacts of the informal settlement on river water quality, especially as regards nutrient contamination from wastewater. The land use and climate change scenarios serve as a warning of the long term consequences of inevitable land use and climate changes in informal settlements.
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Albright, Amy N. "An Analysis of Slope Erosion and Surface Changes on Off-Road Vehicle Trails in Southeastern Ohio." Ohio University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1276715617.
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Rauch, Alan F. "EPOLLS: An Empirical Method for Prediciting Surface Displacements Due to Liquefaction-Induced Lateral Spreading in Earthquakes." Diss., Virginia Tech, 1997. http://hdl.handle.net/10919/30346.
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In historical, large-magnitude earthquakes, lateral spreading has been a very damaging type of ground failure. When a subsurface soil deposit liquefies, intact blocks of surficial soil can move downslope, or toward a vertical free face, even when the ground surface is nearly level. A lateral spread is defined as the mostly horizontal movement of gently sloping ground (less than 5% surface slope) due to elevated pore pressures or liquefaction in undelying, saturated soils. Here, lateral spreading is defined specifically to exclude liquefaction failures of steeper embankments and retaining walls, which can also produce lateral surface deformations. Lateral spreads commonly occur at waterfront sites underlain by saturated, recent sediments and are particularly threatening to buried utilities and transportation networks. While the occurrence of soil liquefaction and lateral spreading can be predicted at a given site, methods are needed to estimate the magnitude of the resulting deformations.
In this research effort, an empirical model was developed for predicting horizontal and vertical surface displacements due to liquefaction-induced lateral spreading. The resulting model is called "EPOLLS" for Empirical Prediction Of Liquefaction-induced Lateral Spreading. Multiple linear regression analyses were used to develop model equations from a compiled database of historical lateral spreads. The complete EPOLLS model is comprised of four components: (1) Regional-EPOLLS for predicting horizontal displacements based on the seismic source and local severity of shaking, (2) Site-EPOLLS for improved predictions with the addition of data on the site topography, (3) Geotechnical-EPOLLS using additional data from soil borings at the site, and (4) Vertical-EPOLLS for predicting vertical displacements. The EPOLLS model is useful in phased liquefaction risk studies: starting with regional risk assessments and minimal site information, more precise predictions of displacements can be made with the addition of detailed site-specific data. In each component of the EPOLLS model, equations are given for predicting the average and standard deviation of displacements. Maximum displacements can be estimated using probabilities and the gamma distribution for horizontal displacements or the normal distribution for vertical displacements.<br>Ph. D.
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Fang, Kun. "Progression and onset of undercut slope failure observed by surface velocity in physical models subjected to arch action." Kyoto University, 2019. http://hdl.handle.net/2433/242486.
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Rizo, Steven R. "Quantifying the Effect of Topographic Slope on Lava Flow Thickness: A First Step to Improve Lava Flow Volume Estimation Methods." Scholar Commons, 2018. http://scholarcommons.usf.edu/etd/7222.
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The volume of lava flows provide important information on the magnitude of volcanic eruptions, and accurate volumes are necessary to produce reliable models of lava flow emplacement or constrain the internal structure of volcanoes. The most accurate lava flow volumes are obtainable when the topography before and after an eruption are both known, but information for the topography before lava flow emplacement is absent in non-historic lava flows. To calculate the volume of non-historic lava flows, this pre-emplacement topography needs to be reconstructed. Common methods for this include using inverse distance-weighted averages or global polynomial interpolation methods, but these can still underestimate the volume of the flow, and the surface of the flow itself is not considered in these interpolations. A new calculation method seems necessary to better constrain the volume of lava flows, and including the lava flow surface in the volume calculation, given that it is generally excluded during interpolation of pre-emplacement topography, may be the solution to improving lava flow volume calculation for flows where the base surface is unknown. The 2012-2013 Tolbachik lava flow is used to look at potential relationships due to the availability of elevation data before and after the eruption. A quantitative analysis on the relationships between the slope of topography before and after lava flow emplacement and on the relationship between the slope and thickness of lava flows is performed. In addition to this, the slope of the topography calculated over local and regional scales is used as a new interpolation method, and the calculated thickness from the interpolated surface is compared to the known thickness for the lava flow.
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Gualchieri, Leonardo. "Simulation of bistatic radar experiments with deep space missions." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/9682/.
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L’obiettivo del lavoro esposto nella seguente relazione di tesi ha riguardato lo studio e la simulazione di esperimenti di radar bistatico per missioni di esplorazione planeteria. In particolare, il lavoro si è concentrato sull’uso ed il miglioramento di un simulatore software già realizzato da un consorzio di aziende ed enti di ricerca nell’ambito di uno studio dell’Agenzia Spaziale Europea (European Space Agency – ESA) finanziato nel 2008, e svolto fra il 2009 e 2010. L’azienda spagnola GMV ha coordinato lo studio, al quale presero parte anche gruppi di ricerca dell’Università di Roma “Sapienza” e dell’Università di Bologna.
Il lavoro svolto si è incentrato sulla determinazione della causa di alcune inconsistenze negli output relativi alla parte del simulatore, progettato in ambiente MATLAB, finalizzato alla stima delle caratteristiche della superficie di Titano, in particolare la costante dielettrica e la rugosità media della superficie, mediante un esperimento con radar bistatico in modalità downlink eseguito dalla sonda Cassini-Huygens in orbita intorno al Titano stesso.
Esperimenti con radar bistatico per lo studio di corpi celesti sono presenti nella storia dell’esplorazione spaziale fin dagli anni ’60, anche se ogni volta le apparecchiature utilizzate e le fasi di missione, durante le quali questi esperimenti erano effettuati, non sono state mai appositamente progettate per lo scopo. Da qui la necessità di progettare un simulatore per studiare varie possibili modalità di esperimenti con radar bistatico in diversi tipi di missione.
In una prima fase di approccio al simulatore, il lavoro si è incentrato sullo studio della documentazione in allegato al codice così da avere un’idea generale della sua struttura e funzionamento. È seguita poi una fase di studio dettagliato, determinando lo scopo di ogni linea di codice utilizzata, nonché la verifica in letteratura delle formule e dei modelli utilizzati per la determinazione di diversi parametri.
In una seconda fase il lavoro ha previsto l’intervento diretto sul codice con una serie di indagini volte a determinarne la coerenza e l’attendibilità dei risultati. Ogni indagine ha previsto una diminuzione delle ipotesi semplificative imposte al modello utilizzato in modo tale da identificare con maggiore sicurezza la parte del codice responsabile dell’inesattezza degli output del simulatore.
I risultati ottenuti hanno permesso la correzione di alcune parti del codice e la determinazione della principale fonte di errore sugli output, circoscrivendo l’oggetto di studio per future indagini mirate.
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Luo, Lei. "Proposing an improved surface dryness index to estimate soil moisture based on the temperature vegetation dryness index." Thesis, Kansas State University, 2016. http://hdl.handle.net/2097/34605.
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Master of Arts<br>Department of Geography<br>Douglas Goodin<br>In this thesis, I proposed a new surface dryness index based on the slope of soil moisture isolines in the Land Surface Temperature/Normalized Difference Vegetation Index (LST/NDVI) feature space. This index, referred to here as Dryness Slope Index (DSI), overcomes the problem of Temperature Vegetation Dryness Index (TVDI) having different basis when calculating TVDI values across different images. This problem is rooted in the definition of TVDI whose calculation depends on the position of the “dry edge” and “wet edge” of pixels’ values in the LST/NDVI space of a specific image. The “wet edge” has a fairly stable physical meaning, which represents soil at field capacity or above, and it remains stable across a time series of images. However, the position of “dry edge” represents the driest condition in the image, which does not necessarily mean that the soil is completely dry. Therefore, the value of TVDI calculated from different images is not based on an invariant dry edge value as its baseline, and it is therefore likely to lead to incorrect conclusion if used without extra examination. This problem manifests itself when comparing TVDI values from different images with meteorological data. Results from similar analyses done with DSI showed more reasonable match with the validation data, indicating DSI is a more robust surface dryness index than TVDI.
Having verified DSI can be effectively used in estimating soil moisture, I applied DSI on Landsat5 TM to study the relationship between soil moisture and land cover, slope, aspect, and relative elevation. Results showed that land cover accounts the most for variations of estimated soil moisture. I also applied DSI on a long time-series (2000 to 2014) of MODIS data trying to explore the temporal evolution of soil moisture in the entire Flint Hills ecoregion. Results showed little correlation between time and estimated soil moisture, indicating that no noticeable changes in soil moisture has been found through all these years.
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Beazley, Melanie J. "The significance of organic carbon and sediment surface area to the benthic biogeochemistry of the slope and deep water environments of the northern Gulf of Mexico." Thesis, Texas A&M University, 2003. http://hdl.handle.net/1969/534.
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Moretto, Renata Lima. "Análise dos efeitos da vegetação na proteção de taludes rodoviários e proposição de alternativas de revegetação na BR-386." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2012. http://hdl.handle.net/10183/60725.
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Esta dissertação discute o emprego de técnicas de estabilização de taludes rodoviários de corte e aterros utilizando drenagem superficial e vegetação. Os conceitos de aplicação de vegetação no aumento da resistência do solo, diminuição da poro-pressão e diminuição da erosão superficial do terreno são revisados. O trabalho discute a importância da interação solo-vegetação, sua influência em taludes, a importância da matéria orgânica nos solos, a sucessão vegetal com vegetação nativa. Estes conceitos foram utilizados na análise de um trecho da BR386, entre a entrada para a via de acesso a Progresso até Canoas, atualmente em processo de duplicação. A partir da inspeção de campo foram identificados os principais problemas de instabilidade e erosão da obra. Foram coletadas seis amostras de solos de quatro taludes da obra para caracterização e para melhor descrição dos problemas de ruptura superficial e controle de erosão nos cortes e aterros analisados. Os materiais amostrados envolveram duas amostras com característica de argila de alta plasticidade, uma argila de baixa plasticidade, uma areia siltosa não plástica, uma areia argilosa e uma areia argilosa não plástica. Foram analisados os problemas encontrados em campo, em função do tipo de materiais, tendo sido propostas soluções adaptadas a cada caso, principalmente focando problemas referentes à drenagem e a busca de soluções ambientais eficazes e com preservação do caráter paisagístico.<br>This work discusses the use of stabilization techniques for road cuttings and embankments using drainage and vegetation. The concepts of increase soil strength due to vegetation, decrease of the pore pressure and reduction in erosion of the ground surface are reviewed. The work also discusses the importance of soil-vegetation interactions, their influence on slopes, the importance of organic matter in soils and plant succession with native vegetation. These concepts were used in the analysis of a length of the BR386 highway, between the entrance to the access route to Progress up to Canoas, currently in the process of duplication. From the field inspection the main problems of instability and erosion of the works were identified. Six soil samples were collected from four slopes for soil characterization and better description of the superficial instabilities and erosion control in the cuts and embankments analyzed. The materials involved two samples with characteristic of high plasticity clay, low plasticity clay, non plastic silty sand and sand clay not plastic. The problems encountered in the field were analyzed, considering the type of soils involved and proposals of solutions have been made adapted for each case, mainly focusing on drainage and the search for effective environmental solutions which preserve the landscape character.
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Al-Qahtani, Marei Hussain. "An assessment of the relationships between the surface soil properties and components of slope and vegetation in the Upper Wadi Bishah Basin, Saudi Arabia." Thesis, University of Hull, 1998. http://hydra.hull.ac.uk/resources/hull:7005.
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This study, the first of its kind undertaken in Saudi Arabia, investigates and evaluates the condition of soil and vegetation and the relationship between them, as well as their relationship with slope components in the Upper Wadi Bishah basin, south-west Saudi Arabia. It is based mainly on quantitative and laboratory analysis, and provides a scientific basis for exploitation of the basin's slopes and conservation of its soil and vegetation. The findings reveal that floristic diversity of the research area is low. Only 62 perennial species belonging to 49 genera and 28 families were recorded in the upper Wadi Bishah basin. Of these, only 8 species or 12.9% of all species recorded, account for 89% of the absolute frequency of species in the basin. Although the vegetation density in this basin is low (2.71/ 100 m²), it is considered relatively high compared with other areas in Saudi Arabia. However, great diversities in density and distribution of vegetation were found between slope segments, and also generally between the south-west and north-east parts of the basin. The floristic composition and distribution of main plant groups were found to reflect the condition of soil and the topographical variety in the wadi basin. Also, it was found that over-grazing, particularly in north-east of the basin, is reflected in deterioration and degradation of vegetation and soil. In terms of soil properties, this study demonstrates quantitatively that the soil of south-west Wadi Bishah basin is generally loamy sand, shallow and somewhat rich in moisture, organic matter, organic carbon, nitrogen and phosphorus, and lacking in CaC0₃, potassium, electrical conductivity and pH, compared with the north-east of the basin. In the north-east of the Wadi Bishah basin, the soil is mostly sandy loam to sand, deep and very lacking in moisture, organic matter, organic carbon, nitrogen and phosphorus. Also, this region is affected by salinity problems. On the vertical level, deeper soils were found in the lower slopes and shallow soils found in the middle and upper slopes. Soil moisture, potassium and electrical conductivity increase down-slope and decrease in the middle and upper slopes. Soil organic matter, CaC0₃ and pH decrease going along the slope units from the top to the bottom. This study has revealed that slope angle and slope gradient have negative significant relationships with soil depth, sand content, potassium, soil pH and electrical conductivity, and positive significant relationships with moisture, silt content, organic matter, organic carbon and nitrogen. Slope length has inverse significant relationships with organic matter, organic carbon and nitrogen, and positive significant relationships with soil depth and potassium. None of the soil properties are associated significantly with slope form. Vegetation cover value and vegetation density are significantly correlated with almost all soil properties. Only electrical conductivity and clay content are not significantly associated with vegetation density. It is clearly demonstrated by this study that 51%, 27%,14%,56%,56%,12%, 45%, 6%, 6%, 31 % and 1 % of the variation in soil depth, moisture, texture, organic matter, organic carbon, CaC0₃, nitrogen, phosphorus, potassium, soil pH and electrical conductivity respectively relate to the function (or to the variation) of slope angle, slope gradient, slope length, vegetation cover value and vegetation density.
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Almeida, CÃcero Lima de. "Impacto da recuperaÃÃo de Ãrea degradada sobre as respostas hidrolÃgicas e sedimentolÃgicas em ambiente semiÃrido." Universidade Federal do CearÃ, 2011. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=6830.
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Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico<br>As regiÃes semiÃridas compreendem Ãreas muito sensÃveis Ãs alteraÃÃes do seu ambiente natural. O semiÃrido brasileiro, por ser um dos mais populosos do mundo, està mais susceptÃvel Ãs atividades antrÃpicas, como o desmatamento para atividades agrosilvopastoris. Esta pesquisa foi desenvolvida no Ãmbito do projeto âEstudos dos processos de degradaÃÃo/desertificaÃÃo e suas relaÃÃes com o uso da terra em sistemas de produÃÃo no semiÃrido cearense: o caso da microrregiÃo de Sobral â CearÃâ. A Ãrea experimental localiza-se no municÃpio de IrauÃuba, inserida em um dos nÃcleos de desertificaÃÃo do semiÃrido brasileiro. O clima da regiÃo à do tipo quente e semiÃrido com chuvas de verÃo (mÃdia anual de 530 mm) e Ãndice de aridez 0,34. O solo à do tipo Planossolo NÃtrico Ãrtico tÃpico, A fraco; e a vegetaÃÃo nativa à do tipo Caatinga arbustiva aberta. A principal atividade econÃmica da regiÃo à a pecuÃria extensiva (bovino e ovino) em sobrepastejo, sem uso de prÃticas conservacionistas. O presente trabalho tem como objetivo comparar os processos hidrossedimentolÃgicos de duas encostas em ambiente semiÃrido: uma (370 mÂ) està submetida à prÃtica de pousio desde 2000; enquanto que a outra (468 mÂ) se encontra degradada, sendo usada como Ãrea de pastagem hà mais de vinte anos. As duas encostas possuem as mesmas condiÃÃes de solo, clima e relevo, diferenciando-se somente quanto ao uso e à cobertura do solo. SÃo comparadas analiticamente variÃveis hidrolÃgicas e sedimentolÃgicas. Os experimentos foram realizados entre 01 de janeiro de 2010 e 15 de abril de 2011. Para promover essa comparaÃÃo foram coletados dados de precipitaÃÃo (lÃmina e intensidade), escoamento superficial e perda de solo. A precipitaÃÃo foi de 264 mm em 2010 e de 445 mm atà 15 de abril de 2011, tendo sido registrados 55 eventos nos 16 meses. As chuvas de IrauÃuba demonstraram alta variabilidade espacial: hà diferenÃa estatÃstica (nÃvel de significÃncia de 5%) entre os dois pluviÃmetros usados na pesquisa, embora estejam a uma distÃncia de apenas 200 m. O padrÃo hidrolÃgico das chuvas na regiÃo à de intermediÃrio a atrasado (70% dos eventos), o que causa maior potencial erosivo. Conclui-se, a partir da anÃlise comparativa, que os dez anos de pousio reduziram em 60% o escoamento superficial em relaÃÃo à encosta degradada. A menor precipitaÃÃo capaz de gerar escoamento superficial foi 7,2 mm na encosta degradada, enquanto que esse valor foi de 8,6 mm para a encosta em pousio. Isso demonstra o incremento de abstraÃÃo inicial da encosta preservada, ou seja, sua maior capacidade de retenÃÃo de umidade. O incremento da capacidade de retenÃÃo se dà atravÃs da interceptaÃÃo vegetal, da serrapilheira e da camada superficial do solo. No entanto, observou-se que a maior precipitaÃÃo incapaz de gerar escoamento superficial foi idÃntica (17 mm) nas duas encostas. A explicaÃÃo para tal resultado à que o parÃmetro dominante nesse processo à a estrutura do solo: embora haja diferenÃas na superfÃcie dos solos, os dez anos de pousio ainda nÃo foram capazes de alterar sua estrutura, conforme avaliou Sousa em pesquisa independente. Observou-se que a taxa de decaimento da vazÃo foi sensivelmente afetada pela prÃtica de pousio: a taxa, de 0,107 min-1 na encosta degrada, decresceu para 0,045 min-1 na encosta preservada. A menor taxa de decaimento de vazÃo na encosta em pousio indica o inÃcio da recuperaÃÃo de seu escoamento de base, o que favorece maior permanÃncia da Ãgua no corpo hÃdrico. Os dez anos de pousio tambÃm foram capazes de reduzir a perda de solo. Essa reduÃÃo, de 83% em relaÃÃo à encosta degradada, induz à melhoria das condiÃÃes fÃsicas, quÃmicas e biolÃgicas do solo, responsÃveis pelo incremento da produÃÃo vegetal. Conclui-se, com base nos experimentos aqui realizados, que os dez anos de pousio melhoraram, de modo mensurÃvel, as condiÃÃes hidrolÃgicas e sedimentolÃgicas na encosta semiÃrida. A prÃtica de pousio, portanto, pode ser adotada para fins de recuperaÃÃo de Ãreas de Caatinga degradada. Sugere-se que sejam realizadas novas investigaÃÃes, que avaliem a associaÃÃo dessa prÃtica a outras, a fim de intensificar o processo de recuperaÃÃo de Ãreas degradadas no semiÃrido
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Atsawakaewmongkhon, Siripatra. "Effet des surfaces inclinées au sol sur le contrôle postural et la fonction de la cheville." Electronic Thesis or Diss., université Paris-Saclay, 2024. http://www.theses.fr/2024UPASW006.
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Le maintien de la posture debout sur la surface inclinée est reconnu comme un défi de coordination corporelle dans l'activité humaine. La surface inclinée est considérée comme un environnement inhabituel qui interfère donc avec le contrôle de l'équilibre. D'ailleurs, cette situation se retrouve régulièrement dans la vie quotidienne (ex. colline, rue pentue, rampe d'accès, etc.). Cette thèse s'intéresse à l'effet de l'inclinaison de la surface d'appui au sol à 7 et 15 degrés sur le contrôle postural et la fonction de la cheville à travers trois différentes études. Nos deux premières études se sont intéressées à la posture debout statique sur une surface inclinée dans le plan sagittal et frontal. Nous avons constaté un effet asymétrique sur la stabilité pour l'inclinaison en avant (PF) et en arrière (DF) et symétrique pour les inclinaisons latérales (RI/LI) de la surface d'appui. En effet, les inclinaisons de surface d'appui, DF et RI/LI, entraînent une plus grande altération de la chaîne de mobilité articulaire, ce qui nécessite une adaptation motrice (système sensoriel, effecteur) organisée par le système nerveux central (SNC) afin de maintenir l'équilibre postural. Au contraire, la situation PF7 améliore l'équilibre postural comparativement à la position horizontale (H0) de référence, probablement en raison de facteurs biomécaniques proches rencontrés lors du port de talons. Par la suite, nous nous sommes interrogés sur l'effet de l'inclinaison de la surface d'appui (étude 3) sur la performance et les ajustements posturaux anticipateurs (APAs), lors d'une tâche de pointage unilatérale réalisée à vitesse maximale. Nos résultats ont confirmé que les ajustements posturaux sont influencés par l'inclinaison de la surface, ce qui a entraîné une diminution de l'amplitude des APAs. Afin que l'effet des APAs soit maintenu et que la performance reste constante, le SNC doit alors augmenter la durée des APAs. Les niveaux de performance en termes de pics d'accélération du mouvement de pointage restent ainsi inchangés dans les conditions de surface inclinée. Pour conclure, ce travail de thèse a permis de mettre en évidence que l'inclinaison de la surface d'appui au sol altère la capacité posturo-cinétique en modifiant notamment la fonction de la cheville via le système sensori-moteur et effecteur en fonction de la direction et de l'amplitude d'inclinaison de la surface. Ces travaux ouvrent des perspectives théoriques mais aussi des perspectives d'implications pratiques sur les stratégies d'amélioration de la fonction d'équilibre dans le domaine clinique, ergonomique, professionnel, sportif, etc<br>Standing on the surface slope has been reported as a challenge to body coordination since it is considered an unusual environment that interferes with balance control. Moreover, this situation can be found regularly in everyday life (e.g., steep hills, streets, ramps, etc.). This thesis aims to explorer the effect of the surface slope at 7 and 15 degrees on postural control and ankle function through three different studies. Our first two studies focus on a static standing posture on a surface slope in the sagittal and frontal planes. The results showed an asymmetrical effect between declined (PF) and inclined (DF) surface slopes and a symmetrical effect on stability between lateral tilts (RI/LI) surface slopes to the left and right. Indeed, DF and RI/LI induce a greater alteration of the joint mobility chain, which requires greater motor adaptation (via sensory, effector system) organized by the central nervous system (CNS) to maintain postural balance. On the other hand, a small amplitude of inclined surface (PF7) has a better effect, certainly thanks to its biomechanics and its similarity to the wearing of low-heeled shoes. Subsequently, we investigated the effect of surface slope on performance and anticipator postural adjustments (APAs) (study 3) during a unilateral pointing task performed at maximum speed. Our results confirmed that the postural adjustments are influenced by surface inclination, resulting in a decrease in APA amplitude. In order to maintain the effect of APAs and to preserve performance, the CNS must generate more APA durations. As a result, performance levels regarding maximum pointing movement remained unchanged among experimental conditions. In conclusion, this thesis work has shown that the surface slope alters postural-kinetic capacity, in particular by modifying ankle function via the sensorimotor and effector system, depending on the direction and amplitude of surface inclination. This work illuminates theoretical perspectives and also has practical implications for strategies to improve balance function in clinical, ergonomic, professional, sporting, and other fields
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Badewien, Tanja Verfasser], Jürgen [Akademischer Betreuer] [Rullkötter, and Hans-Jürgen [Akademischer Betreuer] Brumsack. "Origin and characteristics of plant signals in surface and subrecent sediments of the southwest African continental slope / Tanja Badewien. Betreuer: Jürgen Rullkötter ; Hans-Jürgen Brumsack." Oldenburg : BIS der Universität Oldenburg, 2015. http://d-nb.info/1072500639/34.
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Brighi, Giancorrado. "Data Analysis of Cassini Bistatic Radar Experiments." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/24323/.
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The purpose of this work is to analyse bistatic radar data collected by the Cassini spacecraft about Titan's surface, providing profiles of dielectric constant and rms surface slope with horizontal scales of centimeters to meters. These properties are plotted against longitudes and latitudes of Titan, supported by discussions about the consistency between computed values and present knowledge of general features of Titan geomorphology.
The entire work is carried out on Python, with the help of the spiceypy package from NASA NAIF, as well as other useful packages like cartopy, scipy and numpy. General algorithms for signal processing of the bistatic radar data are developed, aimed at obtaining the spectra of the echoes scattered by Titan's surface. Once the reflections' spectra are available, the rms slope and the dielectric constant can be computed.
The assessment of the rms slope, proportional to the spectral broadening of the echoes, consists on fitting echoes' spectra by means of a Gaussian template, to later evaluate the full-width half-power of the fitting curve. The dielectric constant is computed from the power ratio between orthogonally polarized components of signal reflections from Titan, and from the knowledge of the incidence angle of reflection.
Five flybys, of the thirteen available ones, have been chosen to carry out the following study, trying to analyse bistatic observations spanning over regions of Titan expected to be morphologically different. As a general trend, the dielectric constant estimates are consistent with the expected materials covering the surface of the planet, while the rms slope results are more valuable if read in a comparative way instead of looking at them from an absolute point of view.
The main issues with data analysis of bistatic radar experiments are also mentioned, from the inapplicability of the quasi-specular model to beam-limitation of computed results, and sometimes tackled in a qualitative manner.
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Zhu, Qunzhi. "Modeling and Measurements of the Bidirectional Reflectance of Microrough Silicon Surfaces." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5062.
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Bidirectional reflectance is a fundamental radiative property of rough surfaces. Knowledge of the bidirectional reflectance is crucial to the emissivity modeling and heat transfer analysis. This thesis concentrates on the modeling and measurements of the bidirectional reflectance for microrough silicon surfaces and on the validity of a hybrid method in the modeling of the bidirectional reflectance for thin-film coated rough surfaces.
The surface topography and the bidirectional reflectance distribution function (BRDF) of the rough side of several silicon wafers have been extensively characterized using an atomic force microscope and a laser scatterometer, respectively. The slope distribution calculated from the surface topographic data deviates from the Gaussian distribution. Both nearly isotropic and strongly anisotropic features are observed in the two-dimensional (2-D) slope distributions and in the measured BRDF for more than one sample. The 2-D slope distribution is used in a geometric-optics based model to predict the BRDF, which agrees reasonably well with the measured values. The side peaks in the slope distribution and the subsidiary peaks in the BRDF for two anisotropic samples are attributed to the formation of {311} planes during chemical etching. The correlation between the 2-D slope distribution and the BRDF has been developed.
A boundary integral method is applied to simulate the bidirectional reflectance of thin-film coatings on rough substrates. The roughness of the substrate is one dimensional for simplification. The result is compared to that from a hybrid method which uses the geometric optics approximation to model the roughness effect and the thin-film optics to consider the interference due to the coating. The effects of the film thickness and the substrate roughness on the validity of the hybrid method have been investigated. The validity regime of the hybrid method is established for silicon dioxide films on silicon substrates in the visible wavelength range.
The proposed method to characterize the microfacet orientation and to predict the BRDF may be applied to other anisotropic or non-Gaussian rough surfaces. The measured BRDF may be used to model the apparent emissivity of silicon wafers to improve the temperature measurement accuracy in semiconductor manufacturing processes. The developed validity regime for the hybrid method can be beneficial to future research related to the modeling for thin-film coated rough surfaces.
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Rajaguru, Mudiyanselage Thilanki Maneesha Dahigamuwa. "Enhancement of Rainfall-Triggered Shallow Landslide Hazard Assessment at Regional and Site Scales Using Remote Sensing and Slope Stability Analysis Coupled with Infiltration Modeling." Scholar Commons, 2018. https://scholarcommons.usf.edu/etd/7562.
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Landslides cause significant damage to property and human lives throughout the world. Rainfall is the most common triggering factor for the occurrence of landslides. This dissertation presents two novel methodologies for assessment of rainfall-triggered shallow landslide hazard. The first method focuses on using remotely sensed soil moisture and soil surface properties in developing a framework for real-time regional scale landslide hazard assessment while the second method is a deterministic approach to landslide hazard assessment of the specific sites identified during first assessment. In the latter approach, landslide inducing transient seepage in soil during rainfall and its effect on slope stability are modeled using numerical analysis.
Traditionally, the prediction of rainfall-triggered landslides has been performed using pre-determined rainfall intensity-duration thresholds. However, it is the infiltration of rainwater into soil slopes which leads to an increase of porewater pressure and destruction of matric suction that causes a reduction in soil shear strength and slope instability. Hence, soil moisture, pore pressure and infiltration properties of soil must be direct inputs to reliable landslide hazard assessment methods. In-situ measurement of pore pressure for real-time landslide hazard assessment is an expensive endeavor and thus, the use of more practical remote sensing of soil moisture is constantly sought. In past studies, a statistical framework for regional scale landslide hazard assessment using remotely sensed soil moisture has not been developed. Thus, the first major objective of this study is to develop a framework for using downscaled remotely sensed soil moisture available on a daily basis to monitor locations that are highly susceptible to rainfall-
triggered shallow landslides, using a well-structured assessment procedure. Downscaled soil moisture, the relevant geotechnical properties of saturated hydraulic conductivity and soil type, and the conditioning factors of elevation, slope, and distance to roads are used to develop an improved logistic regression model to predict the soil slide hazard of soil slopes using data from two geographically different regions. A soil moisture downscaling model with a proven superior prediction accuracy than the downscaling models that have been used in previous landslide studies is employed in this study. Furthermore, this model provides satisfactory classification accuracy and performs better than the alternative water drainage-based indices that are conventionally used to quantify the effect that elevated soil moisture has upon the soil sliding. Furthermore, the downscaling of soil moisture content is shown to improve the prediction accuracy. Finally, a technique that can determine the threshold probability for identifying locations with a high soil slide hazard is proposed.
On the other hand, many deterministic methods based on analytical and numerical methodologies have been developed in the past to model the effects of infiltration and subsequent transient seepage during rainfall on the stability of natural and manmade slopes. However, the effects of continuous interplay between surface and subsurface water flows on slope stability is seldom considered in the above-mentioned numerical and analytical models. Furthermore, the existing seepage models are based on the Richards equation, which is derived using Darcy’s law, under a pseudo-steady state assumption. Thus, the inertial components of flow have not been incorporated typically in modeling the flow of water through the subsurface. Hence, the second objective of this study is to develop a numerical model which has the capability to model surface, subsurface and infiltration water flows based on a unified approach, employing fundamental fluid dynamics, to assess slope stability during rainfall-induced transient seepage conditions. The developed model is based on the Navier-Stokes equations, which possess the capability to model surface, subsurface and infiltration water flows in a unified manner. The extended Mohr-Coulomb criterion is used in evaluating the shear strength reduction due to infiltration. Finally, the effect of soil hydraulic conductivity on slope stability is examined. The interplay between surface and subsurface water flows is observed to have a significant impact on slope stability, especially at low hydraulic conductivity values. The developed numerical model facilitates site-specific calibration with respect to saturated hydraulic conductivity, remotely sensed soil moisture content and rainfall intensity to predict landslide inducing subsurface pore pressure variations in real time.
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Grappe, Benjamin. "Modèles d'écoulement à surface libre pour la simulation à long terme de la migration des systèmes méandriformes." Phd thesis, Ecole Nationale Supérieure des Mines de Paris, 2014. http://pastel.archives-ouvertes.fr/pastel-01038004.
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Les systèmes méandriformes construisent, à long terme, des architectures sédimentaires composées de corps poreux disséminés dans un volume de sédiments peu perméables. Ces corps sont susceptibles de contenir des ressources naturelles. Afin d'optimiser leur exploitation, il importe d'estimer la répartition et la connectivité de ces corps. À cet effet, Mines-Paristech développe Flumy, un logiciel de modélisation par processus de ces architectures . Cette thèse vise à améliorer la simulation de la migration dans Flumy en introduisant une influence.Pour cela, trois différents modèles ont été reliés entre eux et comparés. Le premier (modèle à pente constante) est celui actuellement en place dans Flumy, héritier des travaux de [Ikeda 1981] et dans lequel la pente de la surface du cours d'eau est constante. Le deuxième (modèle à pente variable) fut proposé par [Lopez 2003]. Il attribue à la surface libre la pente locale de la topographie. Enfin, un dernier modèle (modèle Saint Venant) a été élaboré en modifiant le précédent. L'écoulement moyen, initialement calculé sous une surface libre connue, est désormais obtenu par résolution des équations de Saint Venant sur un fond connu. Ces trois modèles ont été appliqués à la migration à long terme de méandres libres. Les modèles à pente constante et à pente variable ont également été utilisés pour reproduire les méandres confinés de deux rivières canadiennes, la Beaver et la Red Deer.Les résultats montrent un développement plus réaliste des méandres simulés avec le modèle à pente variable que de ceux simulés avec le modèle à pente constante. Cette amélioration est observable dans les méandres isolés (ralentissement de la vitesse d'extension) et dans les trains de méandres (confinement en ceintures de méandres). Le modèle à pente variable permet également une meilleure reproduction de la morphologie des méandres confinés. L'utilisation du modèle Saint Venant apporte les mêmes améliorations dans la simulation des méandres libres, quoique moins prononcées. Il permet surtout de construire une surface libre physique sur une grande variété de fonds, résolvant ainsi une limite identifiée dans le modèle à pente variable.
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Grappe, Benjamin. "Modèles d'écoulement à surface libre pour la simulation à long terme de la migration des systèmes méandriformes." Electronic Thesis or Diss., Paris, ENMP, 2014. http://www.theses.fr/2014ENMP0008.
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Les systèmes méandriformes construisent, à long terme, des architectures sédimentaires composées de corps poreux disséminés dans un volume de sédiments peu perméables. Ces corps sont susceptibles de contenir des ressources naturelles. Afin d'optimiser leur exploitation, il importe d'estimer la répartition et la connectivité de ces corps. À cet effet, Mines-Paristech développe Flumy, un logiciel de modélisation par processus de ces architectures . Cette thèse vise à améliorer la simulation de la migration dans Flumy en introduisant une influence.Pour cela, trois différents modèles ont été reliés entre eux et comparés. Le premier (modèle à pente constante) est celui actuellement en place dans Flumy, héritier des travaux de [Ikeda 1981] et dans lequel la pente de la surface du cours d'eau est constante. Le deuxième (modèle à pente variable) fut proposé par [Lopez 2003]. Il attribue à la surface libre la pente locale de la topographie. Enfin, un dernier modèle (modèle Saint Venant) a été élaboré en modifiant le précédent. L'écoulement moyen, initialement calculé sous une surface libre connue, est désormais obtenu par résolution des équations de Saint Venant sur un fond connu. Ces trois modèles ont été appliqués à la migration à long terme de méandres libres. Les modèles à pente constante et à pente variable ont également été utilisés pour reproduire les méandres confinés de deux rivières canadiennes, la Beaver et la Red Deer.Les résultats montrent un développement plus réaliste des méandres simulés avec le modèle à pente variable que de ceux simulés avec le modèle à pente constante. Cette amélioration est observable dans les méandres isolés (ralentissement de la vitesse d'extension) et dans les trains de méandres (confinement en ceintures de méandres). Le modèle à pente variable permet également une meilleure reproduction de la morphologie des méandres confinés. L'utilisation du modèle Saint Venant apporte les mêmes améliorations dans la simulation des méandres libres, quoique moins prononcées. Il permet surtout de construire une surface libre physique sur une grande variété de fonds, résolvant ainsi une limite identifiée dans le modèle à pente variable<br>Over a long time, Meandering systems build sedimentary architectures composed of porous bodies scattered inside a volume of low-permeability sediments. These bodies may contain natural resources. In order to optimize their mining, it is essential to estimate the distribution and connectivity of such bodies. To this end, Mines ParisTech develops Flumy, a process-based model simulating the formation of these architectures. This thesis aims to improve the simulation of the migration in Flumy by taking into consideration the influence of the local slope.For this purpose, three distinct models were considered in conjunction, and compared. The first one (constant slope model), which constitutes the basis of the current Flumy version, was originally developed by [Ikeda 1981]. The second model (variable slope model), developed by [Lopez 2003], assigns to the free surface the slope of the surrounding topography. Finally, the last model (Saint-Venant model) has been derived from the variable slope model. Initially calculated under a known free surface, the mean flow in each cross-section is now obtained by solving the Saint-Venant equations over a known river bed. Each of those three models has been applied to the simulation of free meanders. Moreover, the constant-slope and variable slope models have been used to reproduce the confined meanders of two Canadian streams.The results point to a more realistic meanders development using the variable slope model than with the constant slope model. This improvement can particularly be observed in individual meanders, whose rate of extension decreases with the age. It is also noticeable in the overall river behavior, which self-confines in a meander belt. The specific morphology of the confined meanders is also better reproduced using the variable slope model than with the constant slope model. Lastly, though a lesser extent, the Saint-Venant model shows the same advantages than the variable slope model. In addition, it allows the construction of a physically meaningful free surface over a wide range of beds and, in doing so, resolves a limit of the variable slope model
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Lertwiriyaprapa, Titipong. "An approximate UTD development for the radiation by antennas near or on thin material coated metallic wedges." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1196281470.
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Almeida, Cícero Lima de. "Impacto da recuperação de área degradada sobre as respostas hidrológicas e sedimentológicas em ambiente semiárido." reponame:Repositório Institucional da UFC, 2011. http://www.repositorio.ufc.br/handle/riufc/17772.
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ALMEIDA, Cícero Lima de. Impacto da recuperação de área degradada sobre as respostas hidrológicas e sedimentológicas em ambiente semiárido. 2011. 132 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Departamento de Engenharia Agrícola, Programa de Pós-Graduação em Engenharia Agrícola, Fortaleza-CE, 2011.<br>Submitted by demia Maia (demiamlm@gmail.com) on 2016-06-17T13:36:15Z
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Previous issue date: 2011<br>As regiões semiáridas compreendem áreas muito sensíveis às alterações do seu ambiente natural. O semiárido brasileiro, por ser um dos mais populosos do mundo, está mais susceptível às atividades antrópicas, como o desmatamento para atividades agrosilvopastoris. Esta pesquisa foi desenvolvida no âmbito do projeto “Estudos dos processos de degradação/desertificação e suas relações com o uso da terra em sistemas de produção no semiárido cearense: o caso da microrregião de Sobral – Ceará”. A área experimental localiza-se no município de Irauçuba, inserida em um dos núcleos de desertificação do semiárido brasileiro. O clima da região é do tipo quente e semiárido com chuvas de verão (média anual de 530 mm) e índice de aridez 0,34. O solo é do tipo Planossolo Nátrico Órtico típico, A fraco; e a vegetação nativa é do tipo Caatinga arbustiva aberta. A principal atividade econômica da região é a pecuária extensiva (bovino e ovino) em sobrepastejo, sem uso de práticas conservacionistas. O presente trabalho tem como objetivo comparar os processos hidrossedimentológicos de duas encostas em ambiente semiárido: uma (370 m²) está submetida à prática de pousio desde 2000; enquanto que a outra (468 m²) se encontra degradada, sendo usada como área de pastagem há mais de vinte anos. As duas encostas possuem as mesmas condições de solo, clima e relevo, diferenciando-se somente quanto ao uso e à cobertura do solo. São comparadas analiticamente variáveis hidrológicas e sedimentológicas. Os experimentos foram realizados entre 01 de janeiro de 2010 e 15 de abril de 2011. Para promover essa comparação foram coletados dados de precipitação (lâmina e intensidade), escoamento superficial e perda de solo. A precipitação foi de 264 mm em 2010 e de 445 mm até 15 de abril de 2011, tendo sido registrados 55 eventos nos 16 meses. As chuvas de Irauçuba demonstraram alta variabilidade espacial: há diferença estatística (nível de significância de 5%) entre os dois pluviômetros usados na pesquisa, embora estejam a uma distância de apenas 200 m. O padrão hidrológico das chuvas na região é de intermediário a atrasado (70% dos eventos), o que causa maior potencial erosivo. Conclui-se, a partir da análise comparativa, que os dez anos de pousio reduziram em 60% o escoamento superficial em relação à encosta degradada. A menor precipitação capaz de gerar escoamento superficial foi 7,2 mm na encosta degradada, enquanto que esse valor foi de 8,6 mm para a encosta em pousio. Isso demonstra o incremento de abstração inicial da encosta preservada, ou seja, sua maior capacidade de retenção de umidade. O incremento da capacidade de retenção se dá através da interceptação vegetal, da serrapilheira e da camada superficial do solo. No entanto, observou-se que a maior precipitação incapaz de gerar escoamento superficial foi idêntica (17 mm) nas duas encostas. A explicação para tal resultado é que o parâmetro dominante nesse processo é a estrutura do solo: embora haja diferenças na superfície dos solos, os dez anos de pousio ainda não foram capazes de alterar sua estrutura, conforme avaliou Sousa em pesquisa independente. Observou-se que a taxa de decaimento da vazão foi sensivelmente afetada pela prática de pousio: a taxa, de 0,107 min-1 na encosta degrada, decresceu para 0,045 min-1 na encosta preservada. A menor taxa de decaimento de vazão na encosta em pousio indica o início da recuperação de seu escoamento de base, o que favorece maior permanência da água no corpo hídrico. Os dez anos de pousio também foram capazes de reduzir a perda de solo. Essa redução, de 83% em relação à encosta degradada, induz à melhoria das condições físicas, químicas e biológicas do solo, responsáveis pelo incremento da produção vegetal. Conclui-se, com base nos experimentos aqui realizados, que os dez anos de pousio melhoraram, de modo mensurável, as condições hidrológicas e sedimentológicas na encosta semiárida. A prática de pousio, portanto, pode ser adotada para fins de recuperação de áreas de Caatinga degradada. Sugere-se que sejam realizadas novas investigações, que avaliem a associação dessa prática a outras, a fim de intensificar o processo de recuperação de áreas degradadas no semiárido
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Moreno, Cinthia de Carvalho. "Efeitos da inclina??o da esteira na marcha de indiv?duos hemipar?ticos cr?nicos." Universidade Federal do Rio Grande do Norte, 2009. http://repositorio.ufrn.br:8080/jspui/handle/123456789/16669.
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Previous issue date: 2009-07-29<br>Objective: To examine the effects of treadmill inclinations on the walking of hemiparetic chronic subjects. Design: Observational descriptive study. Location: Laboratory of human movement analysis. Participants: Eighteen subjects, 10 men and 8 women were evaluated, with a mean age of 55.3 ? 9.3 years and the time since the injury of about 36 ? 22.8 months. Intervention: Not applicable. Main Outcome Measures: All subjects were evaluated for functional independence (Functional Independence Measure - FIM) and balance (Berg Balance Scale). Angular variations of the hips, knees and ankles in the sagittal plane were observed, as well as the speed of the movement (m/s), cadence (steps/min), stride length (m), cycle time (s), step time on the paretic leg and on the non-paretic leg (s), support phase time and balance phase time on the paretic leg (s) and the ratio of symmetry inter-limb as subjects walked on a treadmill at three conditions of inclination (0%, 5% and 10% ). Results: There were angular increases in the initial contact of the hip, knee and ankle, amplitude increase in the hip between 0% and 10% (37.83 ? 5.23 versus 41.12 ? 5.63, p < 0,001) and 5% and 10% (38.80 ? 5.96 versus 41.12 ? 5.63, p = 0,002), amplitude increases in the knee between 0% and 10% (47.51 ? 15.07 versus 50, 30 ? 12.82, p = 0,040), extension decreases in the hip, dorsiflexion increases in the balance phase and in the time of support phase from 0% to 5% (0.83 ? 0.21 versus 0.87 ? 0, 20, p = 0,011) and 0% and 10% (0.83 ? 0.21 versus 0.88 ? 0.23, p = 0,021). Conclusion: The treadmill inclination promoted angle changes as such as the increase of the angle of the hip, knee and ankle during the initial contact and the balance phase and the increase of the range of motion of the hip and knee; furthermore, it also promoted the increase of the support time of the paretic lower limb<br>Objetivo: Analisar os efeitos da inclina??o da esteira el?trica na marcha de indiv?duos com hemiparesia cr?nica. Desenho: Estudo observacional descritivo. Local: Laborat?rio de an?lise do movimento humano da UFRN. Participantes: Foram avaliados 18 indiv?duos, 10 homens e 8 mulheres, com m?dia de idade de 55,3 ? 9,3 anos e tempo de les?o de 36 ? 22,8 meses. Interven??o: N?o se aplica. Medidas: Todos os sujeitos foram avaliados quanto ? independ?ncia funcional (Medida de Independ?ncia Funcional - MIF) e equil?brio (Escala de Equil?brio de Berg). Foi observada a varia??o angular do quadril, joelho e tornozelo no plano sagital e tamb?m a velocidade da marcha (m/s), cad?ncia (passos/min), comprimento da passada (m), tempo do ciclo (s), tempo do passo da perna par?tica e n?o-par?tica (s), tempo de apoio e tempo de balan?o da perna par?tica (s) e raz?o de simetria entre membros enquanto os indiv?duos caminhavam na esteira em tr?s condi??es de inclina??o (0%, 5% e 10%). Resultados: houve aumento do ?ngulo no contato inicial do quadril, joelho e tornozelo, aumento da amplitude do quadril entre 0% e 10% (37,83 ? 5,23 versus 41,12 ? 5,63; p < 0,001) e 5% e 10% (38,80 ? 5,96 versus 41,12 ? 5,63; p = 0,002), aumento da amplitude do joelho entre 0% e 10% (47,51 ? 15,07 versus 50,30 ? 12,82; p = 0,040), diminui??o da extens?o do quadril, aumento da dorsiflex?o no balan?o e aumento no tempo de apoio entre 0% e 5% (0,83 ? 0,21 versus 0,87 ? 0,20; p = 0,011) e 0% e 10% (0,83 ? 0,21 versus 0,88 ? 0,23; p = 0,021). Conclus?o: A inclina??o da esteira promoveu altera??es angulares como o aumento do ?ngulo do quadril, joelho e tornozelo durante o contato inicial e a fase de balan?o e aumento da ADM do quadril e joelho, bem como aumento do tempo de apoio do membro inferior par?tico
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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.
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Accelerated soil erosion is one of the major threats to agricultural production in Ethiopia and the Harerge region is not exceptional. It is estimated that about 1.5 billion tones of soil is being eroded every year in Ethiopia. In the extreme cases, especially for the highlands, the rate of soil loss is estimated to reach up to 300 t ha-1yr-1 with an average of about 70 t ha -1yr-1 which is beyond any tolerable level. The government have made different attempts to avert the situation since 1975 through initiation of a massive program of soil conservation and rehabilitation of severely degraded lands. Despite considerable efforts, the achievements were far bellow expectations. This study was aimed at assessing the effect of some soil properties, rainfall intensity and slope gradients on surface sealing, soil erodibility, runoff and soil loss from selected sites in the Harerge region, eastern Ethiopia, using simulated rainfall. Soil loss was also estimated for the sites using Soil Loss Estimation Model for Southern Africa (SLEMSA) and the Universal soil Loss Equation (USLE). Moreover, the effectiveness of various rates and patterns of wheat residue mulching in controlling soil loss was also evaluated for one of the study sites, (i.e. Regosol of Alemaya University), under both rainfall simulation and field natural rainfall conditions. For most of the erosion parameters, the interaction among soil texture, slope gradient and rainfall intensity was significant. In general however, high rainfall intensity induced high runoff, sediment yield and splash. The effect of slope gradients on most of the erosion parameters was not significant as the slope length was too small to bring about a concentrated flow. The effect of soils dominated by any one of the three soil separates on the erosion parameters was largely dependent on rainfall intensity and slope gradient. The soils form the 15 different sites in Harerge showed different degrees of vulnerability to surface sealing, runoff and sediment yield. These differences were associated with various soil properties. Correlation of soil properties to the erosion parameters revealed that aggregate stability was the main factor that determined the susceptibility of soils to sealing, runoff and soil loss. This was in turn affected by organic carbon content, percent clay and exchangeable sodium percentage (ESP). Soils with relatively high ESP such as those at Babile (13.85) and Gelemso (7.18) were among the lowest in their aggregate stability (percent water stable aggregates of 0.25 –2.0mm diameter); and have highest runoff and sediment yield as compared to other soils in the study. Similarly, most of those soils with relatively low ESP, high organic carbon content (OC%) and high water stable aggregates such as Hamaressa, AU (Alemaya University) vertisol and AU regosol were among the least susceptible to sealing and interrill erosion. Nevertheless, some exceptions include soils like those of Hirna where high runoff was recorded whilst having relatively high OC%, low ESP and high water stable aggregates. Both the SLEMSA and USLE models were able to identify the erosion hazards for the study sites. Despite the differences in the procedures of the two models, significant correlation (r = 0.87) was observed between the values estimated by the two methods. Both models estimated higher soil loss for Gelemso, Babile, Karamara and Hamaressa. Soil loss was lower for Diredawa, AU-vertisol and AU-Alluvial all of which occur on a relatively low slope gradients. The high soil loss for Babile and Gelemso conforms with the relative soil erodibility values obtained under rainfall simulation suggesting that soil erodibility, among others, is the main factor contributing to high soil loss for these soils. The difference in the estimated soil losses for the different sites was a function of the interaction of the various factors involved. Though the laboratory soil erodibility values were low to medium for Hamaressa and Karamara, the estimated soil loss was higher owing to the field topographic situations such as high slope gradient. SLEMSA and USLE showed different degrees of sensitivities to their input variables for the conditions of the study sites. SLEMSA was highly sensitive to changes in rainfall kinetic energy (E) and soil erodibility (F) and less sensitive to the cover and slope length factors. The sensitivity of SLEMSA to changes in the cover factor was higher for areas having initially smaller percentage rainfall interception values. On the other hand, USLE was highly sensitive to slope gradient and less so to slope length as compared to the other input factors. The study on the various rates and application patterns of wheat residue on runoff and soil loss both in the laboratory rainfall simulation and under field natural rainfall conditions revealed that surface application of crop residue is more effective in reducing soil loss and runoff than incorporating the same amount of the residue into the soil. Likewise, for a particular residue application method, runoff and soil loss decreased with increasing application rate of the mulch. However, the difference was not significant between 4 Mg ha-1 and 8 Mg ha-1 wheat straw rates suggesting that the former can effectively control soil loss and can be used in areas where there is limitation of crop residues provided that other conditions are similar to that of the study site (AU Regosols). The effectiveness of lower rates of straw (i.e. less than 4 Mg ha-1 ) should also be studied. It should however be noted that the effectiveness of mulching in controlling soils loss and runoff could be different under various slope gradients, rainfall characteristics and cover types that were not covered in this study. Integrated soil and water conservation research is required to develop a comprehensive database for modelling various soil erosion parameters. Further research is therefore required on the effect of soil properties (with special emphasis to aggregate stability, clay mineralogy, exchangeable cations, soil texture and organic matter), types and rates of crop residues, cropping and tillage systems, mechanical and biological soil conservation measures on soil erosion and its conservation for a better estimation of the actual soil loss in the study sites. Copyright 2004, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. Please cite as follows: Bobe, BW 2004, Evaluation of soil erosion in the Harerge region of Ethiopia using soil loss models, rainfall simulation and field trials, PhD thesis, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-08022004-141533 / ><br>Thesis (PhD (Soil Science))--University of Pretoria, 2004.<br>Plant Production and Soil Science<br>unrestricted
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Barja, Yáñez Miguel Ángel. "On the Slope and Geography of Fibred Surfaces and Threefolds." Doctoral thesis, Universitat de Barcelona, 1998. http://hdl.handle.net/10803/655.
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In this tesis we study numerical propieties of surfaces and threefolds, mainly fibred over curves, the so called "slope" of the fibration. We prove partially a conjecture of Fujita on the semiampleness of the direct image of the relative dualizing sheaf of a fibration.<br/>We give new lower bounds of the slope of a fibred surface depending on data of the general fibre (existence of involutions) and on data of the hole surface (the fibration not being the Albanese morphism, for example). <br/>We study the case of threefolds over curves. We prove that, in general, the relative algebraic Euler characteristic is nonnegative and give lower bound for the slope. We classify the lowest cases of the invariants.
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SOARES, Patrícia Maria de Carvalho. "Busca da superfície de ruptura crítica na análise tridimensional de estabilidade de taludes." Universidade Federal de Goiás, 2010. http://repositorio.bc.ufg.br/tede/handle/tde/656.
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Previous issue date: 2010-08-24<br>The main objective is to develop, implement and evaluate a method to search for surfaces in order to determine the three-dimensional critical surface, corresponding to the lowest factor of safety of the embankment. They are also objectives of this study to evaluate the influence of the strength and elastic parameters the geometry of the slope safety factor and the 3D shape and position of the failure surface, as well as to evaluate the relationship between 2D and 3D safety factors. It was implemented an optimization routine in FORTRAN that performs the search for critical failure surface, whose safety factor is calculated by SAFE-3D program. The SAFE-3D program uses voltages coming from an elastic stress analysis performed by FlexPDE program, which uses the finite element method and provides the shear and normal stresses acting on the slope necessary to calculate the safety factor. For the analysis has been adopted as the ellipsoid shape of the rupture surface. The search method implemented examines safety factors obtained for a finite set of solutions and design variables as the coordinates of the center of the ellipsoid and the size of its three semi-axes. The search algorithm is implemented in successive tests of the factor of safety by SAFE-3D program, varying the position and dimensions of the ellipsoid for the determination of lower safety factor of slope. It was analyzed two examples of slopes, a symmetrical slope which varied the parameters of soil strength and the angle of the slope face and the other was the historic case of slipping Lodalen. The methodology implemented was successful in finding the critical failure surface, achieving consistency in results. The Poisson's ratio was very influential in the results of the safety factors of three-dimensional critical surfaces. It was also observed that there is less difference between the safety factors when keeping the shear stress unacceptable when these tensions are eliminated there is a closeness among the factors of safety.<br>O principal objetivo deste trabalho é desenvolver, implementar e avaliar um método de busca de superfícies de ruptura tridimensionais a fim de determinar a superfície crítica, correspondente ao menor fator de segurança do talude. São também objetivos deste trabalho avaliar a influência dos parâmetros de resistência e elásticos e da geometria do talude no fator de segurança 3D e no formato e na posição da superfície de ruptura, assim como avaliar a relação entre os fatores de segurança bi e tridimensionais. Foi implementada uma rotina de otimização na linguagem FORTRAN que realiza a busca pela superfície de ruptura crítica, cujo fator de segurança é calculado pelo programa SAFE-3D. O programa SAFE-3D utiliza tensões vindas de uma análise elástica de tensões realizada pelo programa FlexPDE, o qual utiliza o método dos elementos finitos e fornece as tensões normais e cisalhantes atuantes no talude necessárias para o cálculo do fator de segurança. Para a análise foi adotado o elipsóide como forma da superfície de ruptura. O método de busca implementado analisa fatores de segurança obtidos para um conjunto finito de soluções tendo como variáveis de projeto as coordenadas do centro do elipsóide e as dimensões dos seus três semi-eixos. O algoritmo de busca implementado consiste em análises sucessivas do fator de segurança através do programa SAFE-3D, variando-se a posição e as dimensões do elipsóide para a determinação do menor fator de segurança do talude. Foram analisados dois exemplos de taludes, um talude simétrico onde foram variados os parâmetros de resistência do solo e o ângulo da face do talude e o outro foi o caso histórico do escorregamento de Lodalen. A metodologia implementada teve êxito na busca pela superfície de ruptura crítica, conseguindo coerência nos resultados encontrados. O coeficiente de Poisson se mostrou muito influente nos resultados dos fatores de segurança tridimensionais de superfícies críticas. Foi observado também que existe uma menor diferença entre os fatores de segurança quando se mantêm as tensões cisalhantes inadmissíveis, quando estas tensões são eliminadas existe uma maior proximidade entre os fatores de segurança.
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Meehan, Christopher Lee. "An Experimental Study of the Dynamic Behavior of Slickensided Surfaces." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/26074.
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When a clay soil is sheared, clay particles along the shear plane become aligned in the direction of shear, forming â slickensidedâ surfaces. Slickensided surfaces are often observed along the sliding plane in field landslides. Because the clay particles along a slickensided surface are already aligned in the direction of shear, the available shear resistance is significantly less than that of the surrounding soil.
During an earthquake, ground shaking often causes landslide movement. For existing landslides or repaired landslides that contain slickensided rupture surfaces, it is reasonable to expect that the movement will occur along the existing slickensided surfaces, because they are weaker than the surrounding soil. The amount of movement that occurs is controlled by the dynamic resistance that can be mobilized along the slickensided surfaces.
The objective of this study was to investigate, through laboratory strength tests and centrifuge model tests, the shearing resistance that can be mobilized on slickensided rupture surfaces in clay slopes during earthquakes. A method was developed for preparing slickensided rupture surfaces in the laboratory, and a series of ring shear tests, direct shear tests, and triaxial tests was conducted to study the static and cyclic shear resistance of slickensided surfaces. Two dynamic centrifuge tests were also performed to study the dynamic shear behavior of slickensided clay slopes. Newmarkâ s method was used to back-calculate cyclic strengths from the centrifuge data.
Test results show that the cyclic shear resistance that can be mobilized along slickensided surfaces is higher than the drained shear resistance that is applicable for static loading conditions. These results, coupled with a review of existing literature, provide justification for using cyclic strengths that are at least 20% larger than the drained residual shear strength for analyses of seismic stability of slickensided clay slopes. This represents a departure from the current state of practice, which is to use the drained residual shear strength as a â first-order approximation of the residual strength friction angle under undrained and rapid loading conditionsâ (Blake et al., 2002).<br>Ph. D.
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Hockman, Kimberly Kearns. "A graphical comparison of designs for response optimization based on slope estimation." Diss., Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/54384.
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The response surface problem is two-fold: to predict values of the response, and to optimize the response. Slope estimation criteria are well suited for the optimization problem. Response prediction capability has been assessed by plotting the average, maximum, and minimum prediction variances on the surface of spheres with radii ranging across the region of interest. Average and maximum prediction bias plots have recently been added to the spherical criteria. Combined with the prediction variance, a graphical MSE criterion results. This research extends these ideas to the slope estimation objective.
A direct relationship between precise slope estimation and the ability to pinpoint the location of the optimum is developed, resulting in a general slope variance measure related to E-optimality in slope estimation. A more specific slope variance measure is defined and analyzed for use in evaluating standard response surface (RS) designs,where slopes parallel to the factor axes are estimated with equal precision. Standard second order RS designs are then studied in light of the prediction and optimization goal distinction. Designs which perform well for prediction of the response do not necessarily estimate the slope precisely.
A spherical measure of bias in slope estimation is developed and used to measure slope bias due to model misspecification and due to the presence of outliers. A study of augmenting saturated orthogonal arrays of strength two to detect lack of fit is included as an application of a combined squared bias and variance measure of MSE in slope.
A study of the designs recommended for precise slope estimation in their robustness to outliers and to missing observations is conducted using the slope bias and general slope variance measures, respectively.<br>Ph. D.
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Oliveira, Jean Lucas Pereira. "Influência da declividade e exposição no desenvolvimento do milho (Zea mays L.) /." Jaboticabal, 2020. http://hdl.handle.net/11449/192273.
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Orientador: Carlos Eduardo Angeli Furlani<br>Resumo: Visto que a demanda de produção de alimentos é crescente no mundo, surge a necessidade de se utilizar melhor os recursos disponíveis nas áreas de cultivo agrícola. O objetivo do estudo foi avaliar o efeito da interação entre declividades do terreno e exposição à radiação solar no desenvolvimento e produtividade da cultura do milho em cada uma das condições de superfície e, além disso, avaliar o índice de estresse hídrico da cultura. O experimento foi conduzido na safra 2018/2019 no município de Jaboticabal, SP, Brasil, na FCAV/UNESP, em estrutura que simula diferentes condições de exposições e declividades. No primeiro, o delineamento utilizado foi o inteiramente casualizado, em esquema 6x4 com cinco repetições, sendo seis declividades (0,10,20,30,40 e 50%) e quatro exposições (Norte, Sul, Leste e Oeste). Foram avaliados componentes fitotécnicos da cultura: altura e massa de matéria seca de planta, massa de mil grãos, produtividade. No segundo trabalho, foram utilizadas três declividades (0, 30 e 50%) e duas exposições (Norte e Sul). Após verificação da normalidade dos dados, usou-se análise de variância pelo Teste F e, quando necessário, aplicou-se o teste de Tukey (p<0,05) para comparação das médias. A exposição da cultura do milho influenciou no desenvolvimento das variáveis diâmetro do colmo, massa de grãos, número de fileiras por espiga e produtividade. O índice de estresse hídrico varia de acordo com a exposição a que as plantas estão submetidas aos raios solares.<br>Abstract: Since the demand for food production is growing in the world, there is a need to make better use of the resources available in agricultural cultivation areas. The objective of the study was to evaluate the effect of the interaction between land slopes and exposure to solar radiation on the development and productivity of the corn crop in each of the surface conditions and, in addition, to evaluate the water stress index of the crop. The experiment was conducted in the 2018/2019 harvest in the municipality of Jaboticabal, SP, Brazil, at FCAV / UNESP, in a structure that simulates different conditions of exposures and declivity. In the first, the design used was completely randomized, in a 6x4 scheme with five repetitions, six slopes (0.10,20,30,40 and 50%) and four exposures (North, South, East and West). Crop phytotechnical components were evaluated: height and dry matter of plant, mass of a thousand grains, productivity. In the second study, three slopes (0, 30 and 50%) and two exposures (North and South) were used. After verifying the normality of the data, analysis of variance was used by the F Test and, when necessary, the Tukey test (p <0.05) was applied to compare the means. The exposure of the corn crop influenced the development of the stem diameter, grain mass, number of rows per ear and productivity variables. The water stress index varies according to the exposure to which the plants are exposed to sunlight.<br>Mestre
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El-Mherig, A. M. "A study of the stability of jointed rock slopes in surface mines." Thesis, University of Nottingham, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.371279.
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Gahrooee, Darab Raiesi. "Data acquisition and stability analysis of jointed rock slopes in surface mines." Thesis, University of Nottingham, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.352959.
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Ковров, Олександр Станіславович, Александр Станиславович Ковров та O. S. Kovrov. "Геомеханічне обґрунтування параметрів стійких укосів кар’єрів в складноструктурному масиві м’яких порід". Thesis, Видавництво НГУ, 2011. http://ir.nmu.org.ua/handle/123456789/152.
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Дисертація на здобуття наукового ступеня кандидата технічних наук за спеціальністю 05.15.09 – «Геотехнічна і гірнича механіка». – ДВНЗ «Національний гірничий університет», Дніпропетровськ, 2011.<br>Диссертация на соискание ученой степени кандидата технических наук по специальности 05.15.09 – «Геотехническая и горная механика». – ГВУЗ «Национальный горный университет», Днепропетровск, 2011.<br>Thesis for obtaining scientific degree of Candidate of Technical Sciences in specialty 05.15.09 - Geotechnical and rock mechanics. – State Higher Educational Institution “National Mining University”, Dnipropetrovs’k, 2011.<br>Дисертація присвячена вирішенню актуальної науково-технічної задачі вдосконалення геомеханічної оцінки стійкості укосів уступів на кар’єрах, що складаються з м’яких розкривних порід, з урахуванням складної геологічної структури, гідрогеологічних характеристик родовища й навантажень від гірничо-транспортного устаткування.
У роботі виконаний аналіз впливу фізико-географічних, природно-геологічних, гідрогеологічних, інженерно-геологічних і гірничо-технічних факторів на геомеханічну стійкість укосів і бортів кар’єрів. Результати моделювання на еквівалентних матеріалах та чисельного моделювання методом кінцевих елементів дозволило проаналізувати геомеханічні процеси у породних уступах і встановити закономірності порушення їх стійкості.
Отримані експериментальним шляхом фізико-механічні характеристики розкривних порід (суглинки, глини) для гірничо-геологічних умов кар’єрів №7 "Північ" й №7 "Південь" Вільногірського ГМК використані для геомеханічної оцінки стійкості укосів уступів залежно від фізико-механічних характеристик, вологості порід і навантажень від гірничо-транспортного устаткування.
Закономірності, отримані в результаті експериментальних досліджень зразків гірських порід і чисельного моделювання використані для розробки рекомендацій із забезпечення геомеханічної стійкості укосів розкривних уступів для гірничо-геологічних та гірничотехнічних умов Мотронівсько-Анновської ділянки Малишевського комплексного циркон-рутил-ільменітового родовища, що планується до введення в експлуатацію на ВГМК.<br>Диссертация посвящена усовершенствованию геомеханической оценки устойчивости откосов уступов на карьерах, сложенных мягкими вскрышными породами, с учетом сложной геологической структуры, гидрогеологических характеристик месторождения и нагрузок от горно-транспортного оборудования.
В работе выполнен анализ влияния физико-географических, природно-геологических, гидрогеологических, инженерно-геологических и горно-технических факторов на геомеханическую устойчивость откосов и бортов карьеров; рассмотрены основные подходы к расчету потенциальных поверхностей скольжения в прибортовом массиве пород, а также аналитические и эмпирические критерии прочности, которые наиболее часто используются в практике геомеханических исследований.
Для моделирования устойчивости откосов и бортов карьеров, сложенных мягкими вскрышными породами, принят критерий прочности Кулона-Мора. В качестве инструмента численного моделирования использована программа конечно-элементного анализа Phase2 компании Rocscience Inc. широко используемая в практике инженерного анализа как в Украине, так и за рубежом.
Использование метода моделирования на эквивалентных материалах позволило проанализировать геомеханические процессы, происходящие при сдвижении массива пород, слагающих породный уступ, и установить закономерности нарушения его устойчивости.
Выполнены серийные испытания образцов на одноплоскостном срезном приборе П10-С и определены физико-механические характеристики вскрышных пород (суглинки, глины) для горно-геологических условий карьеров №7 «Север» и №7 «Юг» Вольногорского ГМК. Полученные экспериментальным путем значения сцепления и угла внутреннего трения использованы для геомеханической оценки устойчивости откосов уступов действующих и проектируемых карьеров ВГМК.
Разработана гидрогеомеханическая модель, описывающая распределение деформаций и напряжений в откосах уступов карьера с учетом физико-механических характеристик верхнего слоя вскрыши и влагонасыщения пород за счет инфильтрации атмосферных осадков. По результатам моделирования определены коэффициенты запаса устойчивости борта карьера в зависимости от физико-механических характеристик, влажности вмещающих пород и внешних нагрузок горно-транспортного оборудования.
Закономерности, полученные в результате экспериментальных исследований образцов горных пород и численного моделирования использованы для разработки рекомендаций по обеспечению геомеханической устойчивости откосов вскрышных уступов для горно-геологических и горнотехнических условий Мотроновско-Анновского участка Малышевского комплексного циркон-рутил-ильменитового месторождения, которое планируется к введению в эксплуатацию на ВГМК.
Разработан алгоритм оценки долговременной геомеханической устойчивости откосов и бортов карьеров, учитывающий геометрические параметры уступов, сложную геологическую структуру породного массива, гидрогеологические характеристики месторождения и нагрузки от горно-транспортного оборудования. Рассчитаны зависимости угла откоса уступа от влажности верхнего вскрышного горизонта суглинков. Установлено, что для существующих гидро-геологических условий с учетом физико-механических свойств пород рекомендуемые значения КЗУ=1,1…1,3 будут обеспечены при угле наклона откоса α=37…47°.
В результате комплексной оценки геомеханической устойчивости откосов разработана номограмма для расчета КЗУ и рациональных геометрических параметров вскрышных уступов, сложенных суглинками. Установлено, что при средней высоте вскрышного уступа 20 м и изменении угла наклона откоса с проектных 37º до рекомендуемых 47º для условий Вольногорского горно-металлургического комбината сокращение объемов вскрышных работ на 1 км длины фронта работ составит ∆V=78,91тыс.м3. В результате корректировки угла наклона откоса и формировании более крутого геометрического профиля уступа, при его высоте Н=20 м, на 10° (α1-α2=47°-37°) рассчитан экономический эффект Сэ=0,72…0,90 млн. грн на 1 км длины фронта горных работ при средней себестоимости вскрыши Св=10,85…13,40 грн/м3.<br>The dissertation is devoted to solving an actual scientific and technical task of improving geomechanical evaluation of slope stability in open-pit benches composed of soft rocks with consideration of complex geological structure, deposit hydro-geological characteristics and loads of mining-transportation equipment.
Analysis of influence of physiographic, geological, hydro-geological, geotechnical and mining-technical factors on geomechanical stability of slopes and pitedges is carried out. Results of simulation of equivalent materials and FEM numerical modeling allowed analyze geomechanical processes in rock benches and ascertain laws of their instability.
Experimentally derived physical and mechanical characteristics of overburden rocks (loams, clays) for geological conditions of open-pits №7 "Sever" and №7 "Yug" of Vil’noghirs’k Mining and Metallurgical Plant (VGMK) are used for geomechanical evaluation of slope stability depending on physical and mechanical characteristics, rock moisture, and external loads from mining and transport equipment.
Regularities obtained in experimental research of rock samples and numerical modeling are used to develop recommendations for ensuring geomechanical slope stability of overburden benches for geological and mining conditions of Motronivs’ko-Annovs’kyi section of Malyshevs’ke complex zircon-rutile-ilmenite placer deposit which is planned to put into exploitation on VGMK.
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Shamekhi, Seyedeh Elham. "Probabilistic assessment of rock slope stability using response surfaces determined from finite element models of geometric realizations." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/48524.
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A new methodology for probabilistic rock slope stability assessment was developed. This methodology enables the analyst to estimate the probability of failure by incorporating the variability of the geometric parameters such as joint orientation and trace length in the stability analysis. This improves the reliability of any future design, remedial action or risk assessment. Although incorporating the variability of material strength parameters into numerical models is common in geotechnical engineering, similar analysis is very challenging when geometric parameters such as dip, dip direction, and trace length are considered non-deterministically. The challenge is related to mesh generation required for each numerical model as the geometric parameters change, resulting in high computational effort. For practical stability assessment, a representative yet computationally efficient number of realizations or numerical models is required. Therefore, commonly used sampling techniques such as the Monte-Carlo method that generate a large number of slope realizations cannot be used.
The new methodology uses the Point Estimate Method to substitute each probabilistic variable by its two point estimates. As the number of probabilistic input parameters increase, the number of point estimates, and accordingly the number of realizations to be modeled, increase exponentially. To compensate for this problem, the methodology uses a ‘design of experiment’ framework to minimize the number of representative realizations needed. While Phase² finite element software is used in this thesis, the methodology is flexible and can be used to increase the efficiency of other numerical tools that require re-meshing to accommodate changes in geometric parameters.
The developed methodology was evaluated for two different slope configurations. Analysis of variance was implemented to identify the significant parameters affecting the factor of safety. To estimate the probability of failure, central composite design was used to generate more realizations of the significant parameters and to fit response surfaces to the factor of safety values. A method is presented to select the most accurate response surface to estimate the probability of failure. This response surface can be used to predict the stability behaviour of any arbitrary geometric realization of the slope without the need for further numerical modelling. The sensitivity of the methodology to the selection of the initial point estimates was investigated and was shown to be unbiased.<br>Applied Science, Faculty of<br>Engineering, School of (Okanagan)<br>Graduate
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Willoughby, Barrie John. "The assessment of a towed laser slopemeter for measuring short scale sea surface wave slopes." Thesis, University of Southampton, 1998. https://eprints.soton.ac.uk/393585/.
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Sharma, Subedi Abhijit. "Quantification of the Effect of Bridge Pier Encasement on Headwater Elevation Using HEC-RAS." Youngstown State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1502982013572665.
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Guizien, Katell. "Les ondes longues internes : génération et interaction avec la houle." Université Joseph Fourier (Grenoble), 1998. http://www.theses.fr/1998GRE10227.
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L'activite economique maritime s'etant eloignee de la cote pour se rapprocher du bord du talus continental, les exploitants se trouvent confrontes a des mouvements baroclines qui peuvent etre de grandes amplitudes, les ondes longues internes. Dans ce memoire, on presente donc deux aspects concernant les ondes longues internes. Dans une premiere partie, la generation des ces ondes lors de l'interaction de la maree externe avec le talus continental a ete etudie. Il a ete montre grace a un modele lineaire d'ondes longues en bi-couche que l'incidence oblique de la maree ainsi que la rotation terrestre n'etaient pas a negliger. Le modele a ete valide en le comparant a des mesures in-situ realisees sur le malin shelf (ecosse). Dans la seconde partie, nous nous sommes interesses a l'interaction de ces ondes longues internes avec la houle de surface. En effet, sur les images sar, on peut observer la signature des ondes internes laissee en surface. Une premiere etude experimentale d'interaction entre une onde solitaire de surface et une onde courte monochromatique barotrope a ete menee simulant la difference d'echelle existant entre une onde longue interne et des vagues de vent. Des dephasages importants de l'onde courte ont ete mesures, en bon accord avec ceux predits par un modele theorique utilisant la technique wkb egalement presente dans ce memoire. Ce modele a aussi conduit a estimer les modulations d'amplitude de l'onde courte a travers la conservation de l'action d'onde mais ce point n'a pu etre teste experimentalement. Enfin, des experiences d'interaction entre une onde solitaire interne et une onde courte externe ont ete menees en milieu stratifie. Les modulations de la phase se sont averees trop faibles pour etre mesurees, et celles de l'amplitude ne sont pas decrites par la conservation de l'action d'onde etablie theoriquement pour le cas de la premiere serie d'experiences.
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English, John Thomas. "Effectiveness of extracting water surface slopes from LIDAR data within the active channel : Sandy River, Oregon, USA /." Connect to title online (Scholars' Bank), 2008. http://hdl.handle.net/1794/9168.
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English, John Thomas 1980. "Effectiveness of Extracting Water Surface Slopes from LiDAR Data within the Active Channel: Sandy River, Oregon, USA." Thesis, University of Oregon, 2009. http://hdl.handle.net/1794/9168.
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x, 108 p. : ill. (some col.) A print copy of this title is available through the UO Libraries. Search the library catalog for the location and call number.<br>This paper examines the capability of LiDAR data to accurately map river water
surface slopes in three reaches of the Sandy River, Oregon, USA. LiDAR data were
compared with field measurements to evaluate accuracies and determine how water
surface roughness and point density affect LiDAR measurements. Results show that
LiDAR derived water surface slopes were accurate to within 0.0047,0.0025, and 0.0014
slope, with adjusted R2 values of 0.35, 0.47, and 0.76 for horizontal intervals of 5, 10, and
20m, respectively. Additionally, results show LiDAR provides greater data density
where water surfaces are broken. This study provides conclusive evidence supporting
use of LiDAR to measure water surface slopes of channels with accuracies similar to
field based approaches.<br>Committee in Charge: W. Andrew Marcus, Chair; Patricia F. McDowell
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Dutton, Anona L. "Process-based simulations of near-surface hydrologic response for a forested upland catchment: the impact of a road /." May be available electronically:, 2000. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
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Zhang, Tao. "A new method of wavelength scanning interferometry for inspecting surfaces with multi-side high-sloped facets." Thesis, University of Huddersfield, 2018. http://eprints.hud.ac.uk/id/eprint/34763/.
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With the development of modern advanced manufacturing technologies, the requirements for ultra-precision structured surfaces are increasing rapidly for both high value-added products and scientific research. Examples of the components encompassing the structures include brightness enhancement film (BEF), optical gratings and so forth. Besides, specially designed structured surfaces, namely metamaterials can lead to specified desirable coherence, angular or spatial characteristics that the natural materials do not possess. This promising field attracts a large amount of funding and investments. However, owing to a lack of effective means of inspecting the structured surfaces, the manufacturing process is heavily reliant on the experience of fabrication operators adopting an expensive trial-and-error approach, resulting in high scrap rates up to 50-70% of the manufactured items. Therefore, overcoming this challenge becomes increasingly valuable. The thesis proposes a novel methodology to tackle this challenge by setting up an apparatus encompassing multiple measurement probes to attain the dataset for each facet of the structured surface and then blending the acquired datasets together, based on the relative location of the probes, which is achieved via the system calibration. The method relies on wavelength scanning interferometry (WSI), which can achieve areal measurement with axial resolutions approaching the nanometre without the requirement for the mechanical scanning of either the sample or optics, unlike comparable techniques such as coherence scanning interferometry (CSI). This lack of mechanical scanning opens up the possibility of using a multi-probe optics system to provide simultaneous measurement with multi adjacent fields of view. The thesis presents a proof-of-principle demonstration of a dual-probe wavelength scanning interferometry (DPWSI) system capable of measuring near-right-angle V-groove structures in a single measurement acquisition. The optical system comprises dual probes, with orthogonal measurement planes. For a given probe, a range of V-groove angles is measurable, limited by the acceptance angle of the objective lenses employed. This range can be expanded further by designing equivalent probe heads with varying angular separation. More complicated structured surfaces can be inspected by increasing the number of probes. The fringe analysis algorithms for WSI are discussed in detail, some improvements are proposed, and experimental validation is conducted. The scheme for calibrating the DPSWI system and obtaining the relative location between the probes to achieve the whole topography is implemented and presented in full. The appraisal of the DPWSI system is also carried out using a multi-step diamond-turned specimen and a sawtooth brightness enhancement film (BEF). The results showed that the proposed method could achieve the inspection of the near-right-angle V-groove structures with submicrometre scale vertical resolution and micrometre level lateral resolution.