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Numerical analyses of stability of a gradually raised tailings damZardari, Muhammad Auchar January 2013 (has links)
Numerical analyses are presented in this thesis to address potential stability problems that may occur during gradual raisings and under seismic loading conditions of Aitik tailings dam in northern Sweden. The dam is mainly raised using upstream construction method. It is planned to raise the dam gradually in several stages. Two dam parts were studied. The first dam part is a straight dam portion, and the second dam part is a corner. The main concerns associated with future raisings of the straight dam part were: (i) the stability of the dam could be affected by an increase in excess pore pressures during sequential raisings, (ii) how to gradually strengthen the dam by using rockfill berms as supports in such a way that required slope stability can be achieved with a minimum volume of rockfill berms, and (iii) if the dam is subjected to seismic loading, whether or not an increase in excess pore pressures could lead to extensive liquefaction which may cause a failure. The problems related to the dam corner were that tension zones and/or low compression zones could develop because of the horizontal pressure of the stored tailings on the inside of the curvature of the dam corner.Numerical analyses were conducted on both the dam parts using finite element method. Two dimensional (2D) plane strain finite element model was utilized to analyse the straight dam. The dam corner was analysed with both the three dimensional (3D) finite element model, and the 2D axisymmetric finite element model. Coupled deformation and consolidation analyses, and slope stability analyses were performed on both the dam parts to simulate gradual raisings, and to compute safety factors. In addition to this, dynamic analyses were carried out on the straight dam part to evaluate the potential for liquefaction, and seismic stability of the dam. The seismic behaviour of the dam was analysed for two cases: (i) a normal case (earthquake of 3.6 Swedish local magnitude), and (ii) an extreme case (earthquake of 5.8 moment magnitude).The results of the straight dam part, with only previously existing rockfill berms, indicate that stability of the dam was reduced due to an increase in excess pore pressures during raisings. Rockfill berms were utilized as supports to raise the dam with enough safety. An optimization technique was utilized to minimize the volume of rockfill berms. This technique could result in significant saving of cost of rockfill berms.The results of the dam corner show that tension zones and/or low compression zones were located on the surface of the dam corner, mainly above the phreatic level. It is interpreted that there is no risk of internal erosion through the embankments because no seepage path occurs above the phreatic level, and a filter zone exists along the slope of the dam. It is suggested to gradually strengthen the dam corner with rockfill berms. The results of the 2D axisymmetric analyses of the dam corner were in a fairly good agreement with those of the 3D analyses. This implies that the 2D axisymmetric analyses are valid for this dam corner. This is an important finding as 2D axisymmetric analyses require much less computational time compared to 3D analyses.The results of the dynamic analyses performed on the straight dam (including additional rockfill berms) suggest that, for the extreme case, liquefaction could occur in a limited zone that is located below the surface near the embankments. For both the normal and the extreme case, (i) seismically induced displacements seem to be tolerable, and (ii) the post seismic stability of the dam is considered to be sufficient.The findings of this study have been practically applied to the Aitik tailings dam. In general, the modelling procedure and the optimization technique to minimize volume of rockfill berms, presented in this study, could be applied to other tailings dams. / Godkänd; 2013; 20130513 (muhauc); Tillkännagivande disputation 2013-05-20 Nedanstående person kommer att disputera för avläggande av teknologie doktorsexamen. Namn: Muhammad Auchar Zardari Ämne: Geoteknik/Soil Mechanics and Foundation Engineering Avhandling: Numerical Analyses of Stability of a Gradually Raised Tailings Dam Opponent: Professor Daichao Sheng, School of Engineering, The University of Newcastle, New South Wales, Australia Ordförande: Professor Sven Knutsson, Institutionen för samhällsbyggnad och naturresurser, Luleå tekniska universitet Tid: Torsdag den 13 juni 2013, kl 10.00 Plats: F1031, Luleå tekniska universitet
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Výroba rohové krytky / Production of corner coverHrdina, Vojtěch January 2020 (has links)
The project elaborated design of injection mould for production of corner cover, which serves to protect a reprobox from mechanical damage. The production possibilities were considered at the beginning. The injection molding technology was chosen from available technologies. The first part of the thesis is theoretic, plastics and injection molding are investigated. The choice of suitable polymer and the entire draft of mold is in the second part of thesis. The final mold is two-cavity with cold runner system. The technical and economic assessment of the proposal is carried out in the last part of thesis.
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Automatický aplikační systém ochranných rohů paletizovaného materiálu / Automatic application system of protecting corners of palletized materialsHavelka, Michal January 2021 (has links)
The diploma thesis is about the design of an automatic application system of edge protection corners to palletized material. As the first the diploma thesis briefly discusses actual principles and solutions in area of palletization. After that, there are 4 potential solutions described and measured by multicriteria evaluation method where the most suitable solution is being chosen. Then the actual act of designing of the chosen solution is described and also there are solved necessary calculations. In the end there is risk analysis of new workplace and the drawing documentation of selected nodes is attached. The diploma thesis’ assignment has been made in cooperation with company PHATEC s.r.o. in Litomyšl.
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Stanovení podobnosti objektů / Object similarity detectionPřidal, Oldřich January 2011 (has links)
The aim of this thesis was to make a program for object finding, object segmentation and similarity object detection in the image. Object are representing by cars. Description of image making, image preprocessing, geometrical transform and Hough transform was written in the theoretical part of the thesis. Also basic morphological operations, corner detection algorithms and methods of object similarity detection were described in this part. The practical part of the thesis focus to realization of single segments from how to make image, through main program analysis and auxiliary functions to similarity results evaluation. Main program is devided to four parts. The program is preprocessed in the first part. The geometrical transforms are used in the second part and the object similarity is detected in the third part. The last part shows the results. The algorithm is realized in C++ language using the OpenCV library.
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Nárožní polyfunkční dům v Táboře / Multifunctional Corner Building in TáborŠkodová, Veronika January 2013 (has links)
The main aim of this thesis is a fabrication drawings on the corner multifunctional building in Camp by urban, architectural and structural engineering solutions.
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Analytical investigations and numerical experiments for singularly perturbed convection-diffusion problems with layers and singularities using a newly developed FE-softwareLudwig, Lars 04 March 2014 (has links)
In the field of singularly perturbed reaction- or convection-diffusion boundary value problems the research area of a priori error analysis for the finite element method, has already been thoroughly investigated. In particular, for mesh adapted methods and/or various stabilization techniques, works have been done that prove optimal rates of convergence or supercloseness uniformly in the perturbation parameter epsilon.
Commonly, however, it is assumed that the exact solution behaves nicely in that it obeys certain regularity assumptions although in general, e.g. due to corner singularities, these regularity requirements are not satisfied. So far, insufficient regularity has been met by assuming compatibility conditions on the data.
The present thesis originated from the question: What can be shown if these rather unrealistic additional assumptions are dropped? We are interested in epsilon-uniform a priori estimates for convergence and superconvergence that include some regularity parameter that is adjustable to the smoothness of the exact solution.
A major difficulty that occurs when seeking the numerical error decay is that the exact solution is not known. Since we strive for reliable rates of convergence we want to avoid the standard approach of the "double-mesh principle". Our choice is to use reference solutions as a substitute for the exact solution.
Numerical experiments are intended to confirm the theoretical results and to bring further insights into the interplay between layers and singularities. To computationally realize the thereby arising demanding practical aspects of the finite element method, a new software is developed that turns out to be particularly suited for the needs of the numerical analyst. Its design, features and implementation is described in detail in the second part of the thesis.
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Deformationsmätning av kubhörnsreflektorer med fotobaserad skanning och terrester laserskanningErkkilä, Mathias, Pettersson, Torkel January 2022 (has links)
Kubhörnsreflektorer används som måltavlor med kontinuerlig och identifierbar reflekterad signalstyrka vid fjärranalys, bland annat för tekniken ”interferometric synthetic aperture radar” [InSAR]. Kubhörnsreflektorer tillämpas exempelvis för bevakning av sättningar i jordytan och kalibrering av [SAR]-system (”synthetic aperture radar”). Hur starkt en kubhörnsreflektor reflekterar satellitsignaler anges med ”radar cross section” [RCS], som minskar vid deformationer såsom avvikelse från ortogonalitet mellan reflektorplåtar, buktighet och ytoregelbundenheter. Därmed är det viktigt att kunna mäta och analysera sådana deformationer. Studiens syfte var att undersöka hur väl fotobaserad skanning [FBS] och terrester laserskanning [TLS] kan användas för att göra deformationsmätningar på kubhörnsreflektorer. En problematik med kubhörnsreflektorer är att ytorna vanligtvis är reflekterande och texturlösa. Skanningen genomfördes i fältmiljö och FBS gjordes med en systemkamera. FBS-tekniken som användes i studien är baserad på Structure-from-Motion [SfM], vilket automatiserar bildmatchning och 3D-modellering. TLS utfördes med en Leica C10 på kort avstånd, cirka 2 m, från kubhörnsreflektorerna. Insamlade punktmoln segmenterades till separata punktmoln motsvarande de enskilda reflektorplåtarna och referensplan skapades för dessa. Referensplanen användes för att mäta vinklar mellan reflektorplåtar i alla punktmoln, med uppmätta avvikelser från ortogonalitet på 0–0,8°. Buktighet mättes som avstånd mellan plåtarnas punktmoln och referensplan och varierade mycket mellan de två reflektorernas sidor och mellan TLS och FBS, i ett spann från 0 till 6 mm. Ytoregelbundenheter i form av popnitar med storlek 0,6 mm kunde mätas i FBS-punktmoln. Mätosäkerheten var generellt något lägre för deformationsmätningar utifrån TLS jämfört med FBS i studien. Både TLS och FBS har begränsningar vid skanning av kubhörnsreflektorer på grund av reflektorernas ytegenskaper. För FBS kan dessa problem minskas med åtgärder i fält, såsom extra fokuspunkter och artificiell yttextur. TLS-resultat påverkades av infallsvinkeln mot reflektorplåtarna vid skanningen, eftersom en stor infallsvinkel leder till få returer och för liten infallsvinkel riskerar att leda till returer med hög intensitet (och felaktig position). Uppmätt deformation i studien skulle motsvara som mest en förlust på strax över en fjärdedel av det maximala RCS-värdet för den studerade reflektortypen. Den största RCS-förlusten i den här studien berodde på uppmätt buktighet i bottenplåten, i kontrast med att RCS-värdet enligt tidigare studier anses mer känsligt för avvikelse från ortogonalitet mellan reflektorplåtar. / Corner reflectors are used as targets with a continuous and identifiable reflected signal in remote sensing, commonly used with interferometric synthetic aperture radar [InSAR]. Corner reflectors are applied for monitoring crustal changes and calibrating synthetic aperture radar [SAR]-systems. The strength of the reflected radar signal is measured with radar cross section [RCS]. The RCS decreases if the reflector has deformations, such as deviation from orthogonality of the reflector plates, the plate curvature and surface irregularities. Therefore, it is important to be able to measure and analyse these kinds of deformations. The aim of this study was to examine how well close-range photogrammetry [CRP] and terrestrial laser scanning [TLS] can be used to measure deformations of corner reflectors. A problematic aspect of corner reflectors are their surfaces, that usually are reflective and textureless. Scanning was conducted in a field environment and CRP was performed with a digital camera. The CRP-technique used in this study is based on Structure-from-Motion [SfM], which automates the image matching and 3D-modeling. TLS was done with a Leica C10 at short range from the corner reflector, about 2 m. The point clouds were segmented into separate point clouds for each reflector plate and reference planes were fitted to them. The reference planes were used to measure angles between reflector plates, with measured deviations from orthogonality between 0-0,8°. Plate curvature was measured as the distance from the point cloud to the reference plane and varied between the reflector sides and between TLS and CRP, in an interval from 0 to 6 mm. Surface irregularities in the shape of pop rivets, 0,6 mm in size, could be measured in the CRP-point clouds. Measurement uncertainties were generally lower in measurements based on TLS compared to CRP. Both TLS and CRP have limitations when scanning corner reflectors, caused by surface properties of the corner reflector. These problems can be reduced for CRP with certain field measures, such as extra focus points and artificial surface texture. The TLS results were affected by the incident angle while scanning, since a large incident angle leads to few return pulses and a too small incident angle may lead to returns with high intensity (and incorrect position). Measured deformation in this study would be equivalent to a reduction of RCS slightly above one fourth of the maximum RCS-value for the studied corner reflector type. In contrast to earlier studies, which say that RCS is most sensitive to lack of orthogonality between the plates, the largest reduction of RCS in this study was caused by the measured plate curvature of the bottom plate.
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Efficient Implementation of 3D Finite Difference Schemes on Recent Processor Architectures / Effektiv implementering av finita differensmetoder i 3D på senaste processorarkitekturerCeder, Frederick January 2015 (has links)
Efficient Implementation of 3D Finite Difference Schemes on Recent Processors Abstract In this paper a solver is introduced that solves a problem set modelled by the Burgers equation using the finite difference method: forward in time and central in space. The solver is parallelized and optimized for Intel Xeon Phi 7120P as well as Intel Xeon E5-2699v3 processors to investigate differences in terms of performance between the two architectures. Optimized data access and layout have been implemented to ensure good cache utilization. Loop tiling strategies are used to adjust data access with respect to the L2 cache size. Compiler hints describing aligned memory access are used to support vectorization on both processors. Additionally, prefetching strategies and streaming stores have been evaluated for the Intel Xeon Phi. Parallelization was done using OpenMP and MPI. The parallelisation for native execution on Xeon Phi is based on OpenMP and yielded a raw performance of nearly 100 GFLOP/s, reaching a speedup of almost 50 at a 83\% parallel efficiency. An OpenMP implementation on the E5-2699v3 (Haswell) processors produced up to 292 GFLOP/s, reaching a speedup of almost 31 at a 85\% parallel efficiency. For comparison a mixed implementation using interleaved communications with computations reached 267 GFLOP/s at a speedup of 28 with a 87\% parallel efficiency. Running a pure MPI implementation on the PDC's Beskow supercomputer with 16 nodes yielded a total performance of 1450 GFLOP/s and for a larger problem set it yielded a total of 2325 GFLOP/s, reaching a speedup and parallel efficiency at resp. 170 and 33,3\% and 290 and 56\%. An analysis based on the roofline performance model shows that the computations were memory bound to the L2 cache bandwidth, suggesting good L2 cache utilization for both the Haswell and the Xeon Phi's architectures. Xeon Phi performance can probably be improved by also using MPI. Keeping technological progress for computational cores in the Haswell processor in mind for the comparison, both processors perform well. Improving the stencil computations to a more compiler friendly form might improve performance more, as the compiler can possibly optimize more for the target platform. The experiments on the Cray system Beskow showed an increased efficiency from 33,3\% to 56\% for the larger problem, illustrating good weak scaling. This suggests that problem sizes should increase accordingly for larger number of nodes in order to achieve high efficiency. Frederick Ceder / Effektiv implementering av finita differensmetoder i 3D på moderna processorarkitekturer Sammanfattning Denna uppsats diskuterar implementationen av ett program som kan lösa problem modellerade efter Burgers ekvation numeriskt. Programmet är byggt ifrån grunden och använder sig av finita differensmetoder och applicerar FTCS metoden (Forward in Time Central in Space). Implementationen paralleliseras och optimeras på Intel Xeon Phi 7120P Coprocessor och Intel Xeon E5-2699v3 processorn för att undersöka skillnader i prestanda mellan de två modellerna. Vi optimerade programmet med omtanke på dataåtkomst och minneslayout för att få bra cacheutnyttjande. Loopblockningsstrategier används också för att dela upp arbetsminnet i mindre delar för att begränsa delarna i L2 cacheminnet. För att utnyttja vektorisering till fullo så används kompilatordirektiv som beskriver minnesåtkomsten, vilket ska hjälpa kompilatorn att förstå vilka dataaccesser som är alignade. Vi implementerade också prefetching strategier och streaming stores på Xeon Phi och disskuterar deras värde. Paralleliseringen gjordes med OpenMP och MPI. Parallelliseringen för Xeon Phi:en är baserad på bara OpenMP och exekverades direkt på chipet. Detta gav en rå prestanda på nästan 100 GFLOP/s och nådde en speedup på 50 med en 83% effektivitet. En OpenMP implementation på E5-2699v3 (Haswell) processorn fick upp till 292 GFLOP/s och nådde en speedup på 31 med en effektivitet på 85%. I jämnförelse fick en hybrid implementation 267 GFLOP/s och nådde en speedup på 28 med en effektivitet på 87%. En ren MPI implementation på PDC's Beskow superdator med 16 noder gav en total prestanda på 1450 GFLOP/s och för en större problemställning gav det totalt 2325 GFLOP/s, med speedup och effektivitet på respektive 170 och 33% och 290 och 56%. En analys baserad på roofline modellen visade att beräkningarna var minnesbudna till L2 cache bandbredden, vilket tyder på bra L2-cache användning för både Haswell och Xeon Phi:s arkitekturer. Xeon Phis prestanda kan förmodligen förbättras genom att även använda MPI. Håller man i åtanke de tekniska framstegen när det gäller beräkningskärnor på de senaste åren, så preseterar både arkitekturer bra. Beräkningskärnan av implementationen kan förmodligen anpassas till en mer kompilatorvänlig variant, vilket eventuellt kan leda till mer optimeringar av kompilatorn för respektive plattform. Experimenten på Cray-systemet Beskow visade en ökad effektivitet från 33,3% till 56% för större problemställningar, vilket visar tecken på bra weak scaling. Detta tyder på att effektivitet kan uppehållas om problemställningen växer med fler antal beräkningsnoder. Frederick Ceder
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Detekce odpovídajících si bodů ve dvou fotografiích / Detection of Corresponding Points in ImagesKomosný, Petr January 2009 (has links)
This thesis is interested in detection of corresponding points in images, which display the same object, eventually some of important elements and synchronizing these images. The aim of this thesis is to find, study and choose suitable algorithm for detecting interesting points in image. This algorithm will be apply at couple of images and in these images will find couples of corresponding points across these images. Functional output of this thesis will be application which will realize choosen interesting points detector, algorithm for finding correspondencies of regions and their synchronizing and joint them to one output image.
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Techniques to Improve Application of Smooth Particle Hydrodynamics in Incompressible FlowsBoregowda, Parikshit 04 November 2019 (has links)
No description available.
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