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Pevnostní analýza nosníku s tenkou stojinou - vliv otvorů a tahového pole / The Stress Analysis of the Beam with Thin Web - Influence of the Holes and Tensile Effect of Web BucklingHorák, Marek January 2014 (has links)
In design of an aircraft structure, the great emphasis is placed on achieving high weight efficiency. This thesis is focused on the stress analysis of the spars with thin web with or without web openings, which is one of the most important parts of the airplane structures. In comparison with traditional spars or beams, which are widely used in civil engineering applications, the design of the beam with thin web is more complicated. Thesis contains useful information for analytical calculation of this type of spars and its verification using finite element method and experimental measurement.
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Odhad varianční matice pro filtraci ve vysoké dimenzi / Covariance estimation for filtering in high dimensionTurčičová, Marie January 2021 (has links)
Estimating large covariance matrices from small samples is an important problem in many fields. Among others, this includes spatial statistics and data assimilation. In this thesis, we deal with several methods of covariance estimation with emphasis on regula- rization and covariance models useful in filtering problems. We prove several properties of estimators and propose a new filtering method. After a brief summary of basic esti- mating methods used in data assimilation, the attention is shifted to covariance models. We show a distinct type of hierarchy in nested models applied to the spectral diagonal covariance matrix: explicit estimators of parameters are computed by the maximum like- lihood method and asymptotic variance of these estimators is shown to decrease when the maximization is restricted to a subspace that contains the true parameter value. A similar result is obtained for general M-estimators. For more complex covariance mo- dels, maximum likelihood method cannot provide explicit parameter estimates. In the case of a linear model for a precision matrix, however, consistent estimator in a closed form can be computed by the score matching method. Modelling of the precision ma- trix is particularly beneficial in Gaussian Markov random fields (GMRF), which possess a sparse precision matrix. The...
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Radnice Brno – Sever / New town hall for the district Brno-NorthJanoušek, Martin January 2015 (has links)
The task of the diploma work was to design a city hall for Brno-North. It is situated in the area of the Blackfields barracks for which I've made urban design in last semester. The concept of the design is based on the simple idea of two patios - one green court surrounded by offices of various official unions for which it serves as an element of calmness and clear communication in the workplace. Second 'patio' is its spatial counterpoint, a large hall where all the significant ongoing negotiations are hold. In short, a relationship of execution and decision. Interiors offer plenty of meeting and communication spaces, meeting rooms, all united by the space at the south side of the building, which opens gradually on each floor offering an overview across the whole space. The mass of the building itself is compact on the outside, long (southern) facade is facing the square. The external appearance of the building is articulated within the construction module and reflects inner spaces. While the facade of the administrative part of the building reflects more the system and repetition, southern facade uses more open and subtle expression.
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Radnice Brno – Sever / New town hall for the district Brno-NorthHrubešová, Martina January 2015 (has links)
In the area of barracks in Brno Černá Pole lies a great potential. Currently is the area closed for public, but it has got a convenient location to become the center of the city part. Urban design is based on historical context and current structure of the barracks. The area wasn´t urbanized before the barracks founding and in the new designed structure we can see the reference to this use. Particular areas, which are determined in the regulation plan design are designed more detailed. The heart of area with the main amenities as sport center, community center, school and town hall is situated in the south east. This location is convenient because of the crossing of the pedestrians routes and axis of view. It is easy to reach this point from different directions. Town Hall determined the square. City Hall building is based on the basic requirements - the representativeness, simple orientation in the buildings and economics. Linear form of the building is divides into two part by staircase hall, which is the center of the house. Part facing the crossing is multifunctional and includes a café, management of city part and a lecture hall. This section can work independently as well as during unofficial days. The second part of building contains offices and staff facilities. On the ground floor is the building surrounded by a colonnade and richly glazed, allowing visual communication exterior and interior. The main entrances to the building are from the square and strett Mathonova. The interior are based on transparency, so the visitors can experience the management of city part.
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On the Influence of Scattering From a Power-pole on an Airport RadarHu, Ao January 2019 (has links)
Power-poles are one of the common massive conducting structures in cities and countryside. To fulfill the remarkable increased electric power demand nowadays, the number and the size of power-poles are also growing over the past few decades. The influence of power-pole on electromagnetic wave propagation is a potential noise source for nearby radio devices like radars. This master thesis project is aiming to analysis the interference of a case where an Amplitude Modulated (AM) signal emitted. We consider here the Stockholm Arlanda Airport’s Very High Frequency (VHF) Omnidirectional Range (VOR) radar scattering by a power-pole 2.6km away.A Method of Moment technique is used to solve the scattering problem. We modeled the power-pole on a blueprint from Svenska Kraftnät. It is meshed in small triangles by AutoCAD and GMSH software, and on that mesh the Rao-Wilton-Glisson (RWG) basis function are formed. A MoM code developed by Makarov determines the bi-static scattering pattern of the power-pole. Four main models have been considered, a one-side power-pole model and the same model with the ground plane, as well as two sides power-pole model and the model with the ground plane. We have assumed that the incident field on the power-pole is a plane wave and that the ground is an infinite PEC surface. The result is presented by the Interference to Signal ratio (ISR) of an airplane receiver when it is flying toward the airport for landing.By the end of the project, we have shown for the considered model that a 50 15dB level of interference is estimated for the interference to signal ratio. This result then suggests that a power-pole may have a little signal interference towards the VOR system radar wave emit awayfrom 2.6km. / Kraftstolpar är vanligt förekommande stora ledande strukturerna i stadsnära regioner. Städer och regioner uppvisar idag en kraftigt ökad efterfrågan på elektricitet, vilket ställer krav på ett kraftnät som klarar av större effekt. Ett sätt att öka effekten är att introducera fler kraftledningar, och där med också öka antalet kraftledningsstolpar. Kraftledningsstolparna kan påverka den elektromagnetiska vågutbredning och är en potentiell bruskälla för närliggande radioenheter som t.ex. radar/signal-anläggningar. Detta examensarbete syftar till att analysera eventuella störningar vid användandet av en amplitudmodulerad (AM) signal. Vi betraktar här Stockholm Arlanda Airport’s Very High Frequency (VHF) Omnidirectional Range (VOR) radarspridning med en kraftstolpe 2,6 km bort.I detta fall används Method of Moment (MoM)-tekniken för att lösa spridningsproblemet. Vi modellerade kraftstolpen baserad på data från Svenska Kraftnät. Stolpen modelleras med små sammankopplade trianglar med hjälp av programvaran AutoCAD och GMSH, och på det nätverket bildas Rao-Wilton-Glisson (RWG) -basisfunktionen. En MoM-kod utvecklad av Makarov bestämmer det bi-statiska spridningsmönstret för kraftstolpen. Fyra huvudmodeller har beaktats, en en-sidig modell av en kraftstolpe med och utan jordplan, liksom en två-sidig modell med och utan jordplan. Vi har antagit att det mot kraftstoplen infallande fältet är en plan våg och att marken är en oändlig prefekt ledande-yta. Resultatet presenteras som en kvot mellan störning i förhållande till signalen (ISR) hos en flygmottagare när den flyger mot flygplatsen för landning.Beräkningarna i projektet visar att för de betraktade modellerna har vi en ISR på -50±15dB. Detta resultat antyder att en kraftstolpe på ett avstånd 2,6 km från VOR-systemet har en lågstörning på VOR-systemets amplitudmodulerade signal.
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Modellbasierte Berechnung der frequenzabhängigen Stromverteilung in räumlich ausgedehnten ErdungssystemenKüchler, Benjamin 14 March 2024 (has links)
Die Auslegung von Erdungsanlagen nach der DIN EN 50522 basiert im Wesentlichen auf der Bewertung der bei Erdfehler auftretenden Erdungs- bzw. Berührungsspannungen. Deren Berechnung setzt die Kenntnis der Fehlerstromaufteilung (bzw. der wirksamen Reduktionsfaktoren) voraus, da nur der Stromanteil, der als Erdungsstrom über der Erdungsimpedanz wirksam wird, tendenziell gefährliche Potentialanhebungen verursacht. Maßgebend für die Verteilung der Ströme im Erdungssystem sind die induktiven Kopplungen zwischen dem fehlerstromführenden Leiter und den zum Sternpunkt zurückführenden Strompfaden. Daraus geht hervor, dass sowohl die räumliche Anordnung der Leiter als auch die Frequenz der Fehlerstromanteile die vorherrschenden Verhältnisse entscheidend beeinflussen. Beide Einflüsse werden in den Standards und der Fachliteratur bis dato nur bedingt betrachtet.
Diese Arbeit befasst sich daher mit der rechnerischen Bestimmung und Bewertung der Potentialanhebungen, welche sich im Falle eines Erdfehlers in Abhängigkeit von den Frequenzanteilen des Fehlerstroms in unterschiedlich aufgebauten Erdungssystemen ergeben. Wesentlicher Bestandteil der Ausführungen ist die Entwicklung eines Modells zur Berechnung der frequenzabhängigen Stromverteilung und den daraus resultierenden Erdungsspannungen in verbundenen Erdungsanlagen. Dieses bildet, in Erweiterung zu bestehenden Ansätzen, insbesondere den Einfluss der dreidimensionalen Anordnung der Leiter auf deren magnetische Kopplungen ab. Durch theoretische Betrachtungen und begleitende Messungen werden die Grenzen derartiger rechnerischer Bewertungsverfahren aufgezeigt.
Anhand einfacher Modellanordnungen wird beispielhaft der Einfluss der räumlichen Struktur des Erdungssystems auf die frequenzabhängige Fehlerstromverteilung, die wirksamen Erdungsimpedanzen und die resultierenden Erdungsspannungen analysiert. Dabei werden explizit Erdfehler an zusammengeschlossenen Hoch- und Niederspannungs-Erdungsanlagen untersucht. Die Ergebnisse zeigen, dass rein zweidimensionale Berechnungsverfahren den theoretischen Worst-Case hinsichtlich der Erdungsspannung nicht abdecken. Für die praktische Anwendung des Modells werden sowohl Vereinfachungen als auch zusätzliche Sicherheitsaufschläge abgeleitet.
Weiterhin erfolgt die modellbasierte Untersuchung einpoliger Fehler in voll- und teilverkabelten Netzen. Im Fokus steht dabei die potentialanhebende Wirkung der Frequenzanteile des einpoligen Fehlerstroms. Es wird aufgezeigt, dass infolge der induktiven Kopplungen ein hoher Anteil des Rückstroms in den beidseitig geerdeten Schirmen der fehlerstromführenden Kabel fließt. Bedingt durch die Frequenzcharakteristik des Reduktionsfaktors wirken die höherfrequenten Anteile des Erdfehlerstroms in vollverkabelten Netzgebieten in deutlich geringerem Maße potentialanhebend als der Grundschwingungsanteil. Daher lassen sich insbesondere für die Erdungssysteme von Kabelnetzen mit Resonanz-Sternpunkterdung vereinfachte Bewertungsmethoden ableiten.
In Summe liefert diese Arbeit einen Beitrag dazu, wie der rechnerische Nachweis zulässiger Berührungsspannungen geführt und das Prozedere zur Auslegung von Erdungsanlagen vereinfacht werden kann. / The design of earthing installations in European high voltage grids has to comply with the standard EN 50522. The determining quantities for the risk assessment are the touch and step voltages occurring during an earth fault. Since the direct estimation of these voltages is complicated, earthing installations are usually assessed by means of the earth potential rise. For the calculation of the earth potential rise the knowledge of the fault current distribution (or the effective reduction factors) is required, since only the proportional current to earth raises the potential of the earthing installations. The inductive coupling between the conductor carrying the fault current and the current paths leading back to the neutral point is decisive for the distribution of the currents in the earthing system. This indicates that both the spatial arrangement of the conductors and the frequency of the fault current components have a determining influence on the prevalent conditions. To date, both influences have only been considered to a minor extent in the standards and technical literature.
This thesis relates to the calculation and evaluation of the earth potential rises in differently structured earthing systems. Thereby, the varying potential raising effect of the harmonics in the earth fault current is examined. For this purpose, a model for the calculation of the frequency-dependent current distribution in interconnected earthing installations is developed. In extension to existing approaches, this model particularly represents the influence of the three-dimensional arrangement of the conductors on their magnetic coupling. Through theoretical considerations and accompanying measurements, the limits of such calculational evaluation methods are demonstrated.
Based on simple model arrangements, the influence of the spatial structure of the earthing system on the frequency-dependent fault current distribution (reduction factors), the effective impedances to earth and the resulting earth potential rise is analysed exemplarily. Thereby, earth faults at interconnected high-voltage and low-voltage earthing installations are investigated explicitly. The results show that two-dimensional calculation methods do not cover the theoretical worst case regarding the earth potential rise. For the practical application of the model, simplifications as well as additional safety surcharges are derived.
Furthermore, model-based investigations of single-pole faults in fully and partially cabled grids are carried out. The focus is on the potential-raising effect of the harmonic components of the single-pole fault current. It is shown that, due to inductive coupling, a high percentage of the return current flows via the shields of the cables carrying the fault current. Due to the frequency characteristic of the reduction factor, in fully cabled grid areas higher-frequency components of the earth fault current have a significantly lower potential-raising effect than the fundamental component. Particularly for the earthing systems of cable grids with resonant earthing, simplified assessment methods can thus be derived.
In summary, this thesis provides a contribution on how to proof permissible touch voltages by calculation and how to simplify the procedure for the assessment of earthing installations in perspective.
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Controller Design for a Gearbox Oil ConditioningTestbed Through Data-Driven Modeling / Regulatordesign för en växellåda oljekonditionering testbädd genom datadriven modellering.Brinkley IV, Charles, Wu, Chieh-Ju January 2022 (has links)
With the exponential development of more sustainable automotive powertrains, new gearbox technologies must also be created and tested extensively. Scania employs dynamometer testbeds to conduct such tests, but this plethora of new and rapidly developed gearboxes pose many problems for testbed technicians. Regulating oil temperature during tests is vital and controllers must be developed for each gearbox configuration; this is difficult given system complexity, nonlinear dynamics, and time limitations. Therefore, technicians currently resort to a manually tuned controller based on real-time observations; a time-intensive process with sub-par performance. This master thesis breaks down this predicament into two research questions. The first employs a replicate study to investigate whether linear system identification methods can model the oil conditioning system adequately. A test procedure is developed and executed on one gearbox setup to capture system behavior around a reference point and the resulting models are compared for best fitment. Results from this study show that such data-driven modeling methods can sufficiently represent the system. The second research question investigates whether the derived model can then be used to create a better-performing model-based controller through pole placement design. To draw a comparison between old and new controllers, both are implemented on the testbed PLC while conducting a nominal test procedure varying torque and oil flow. Results from this study show that the developed controller does regulate temperature sufficiently, but the original controller is more robust in this specific test case. / Med den exponentiella utvecklingen av mer hållbara drivlinor i fordonsindustrin måste nya växellådsteknologier skapas och testas på en omfattande skala. Scania använder sig utav dynamometer testbäddar för att utföra sådana tester, men denna uppsjö av nya och snabbt utvecklade växellådor skapar utmaningar för testbäddsteknikerna. Reglering av oljetemperaturen under testerna är avgörande och därmed måste nya regulatorer utvecklas för varje växellådskonfiguration; detta är problematiskt med tanke på systemkomplexitet, olinjär dynamik samt tidsbegränsning. På grund av detta använder sig testbäddsteknikerna för tillfället av en manuell metod för att ta fram parametrarna till regulatorerna baserat på realtidsobservationer vilket är en tidskrävande process som ofta leder till en underpresterande regulator. Det här masterarbetet bryter ner den nämnda problematiken i två forskningsfrågor. Den första behandlar en replikationsstudie för att undersöka om linjära systemidentifikations metoder kan modellera oljekonditioneringssytemet på ett adekvat sätt. En testprocedur utvecklas och utförs på en växellådskonfiguration för att ta fram en modell för systemet kring en referenspunkt. De resulterande modellerna jämförs för att fastställa vilken metod som bäst beskriver systemet. Resultatet från denna studie visar att sådana data-drivna modelleringsmetoder kan beskriva systemet på ett tillfredsställande sätt. Den andra forskningsfrågan undersöker om den härledda modellen kan användas för att skapa en bättre presterande modellbaserad regulator med hjälp av polplaceringsmetoden. För att kunna göra en jämförelse mellan gamla samt nya regulatorer implementeras båda på testbäddens PLC varvid en nominell testprocedur utförs som varierar vridmoment och oljeflöde. Resultatet från denna studie visar att den framtagna regulatorn kan reglera oljetemperaturen på ett tillfredsställande sätt, däremot är den ursprungliga regulatorn mer robust i det behandlade testfallet.
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Functional Design Employing Miniaturized Electronics with Wireless Signal Provision to a Smartphone for a Strain-Based Measuring System for Ski PolesHentschel, Uwe, Steinbild, Philip Johannes, Dannemann, Martin, Schwaar, Andree, Modler, Niels, Schürer, Axel 03 May 2023 (has links)
The individual monitoring of cross-country skiers’ technique-related parameters is crucial to identifying possible athlete-individual deficits that need to be corrected in order to optimize the athlete’s performance in competition. To be able to record relevant biomechanical parameters during training in the field, the development of measuring systems exploiting the athlete’s full potential is the key. Known mobile monitoring systems for measuring forces on ski poles use comparably heavy uniaxial load cells mounted on the pole with a data logger also attached to the pole or carried by the athlete. Measurements that are more accurate can be acquired using wire-based systems. However, wire-based systems are highly immobile and only usable when the athletes undergo a stationary test, e.g., on a treadmill. This paper focuses on the functional design of a measuring system using specialized, miniaturized electronics for acquiring data from strain sensors. These data are then used to determine the technique-related parameters pole force and angle of bend. The functional design is also capable of transmitting the acquired data wirelessly via Bluetooth to a smartphone that runs a proprietary app. This approach is advantageous regarding mass, dynamic behavior, analyzing functionality, and signal processing compared to the state of the art.
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Monitoring Water and Energy Cycles at Climate Scale in the Third Pole Environment (CLIMATE-TPE)Su, Zhongbo, Ma, Yaoming, Chen, Xuelong, Peng, Xiaohua, Du, Junping, Han, Cunbo, He, Yanbo, Hofste, Jan G., Li, Maoshan, Li, Mengna, Lv, Shaoning, Ma, Weiqiang, Polo, María J., Peng, Jian, Qian, Hui, Sobrino, Jose, van der Velde, Rogier, Wen, Jun, Wang, Binbin, Wang, Xin, Yu, Lianyu, Zhang, Pei, Zhao, Hong, Zheng, Han, Zheng, Donghai, Zhong, Lei, Zeng, Yijian 08 May 2023 (has links)
A better understanding of the water and energy cycles at climate scale in the Third Pole Environment is essential for assessing and understanding the causes of changes in the cryosphere and hydrosphere in relation to changes of plateau atmosphere in the Asian monsoon system and for predicting the possible changes in water resources in South and East Asia. This paper reports the following results: (1) A platform of in situ observation stations is briefly described for quantifying the interactions in hydrosphere-pedosphere-atmosphere-cryosphere-biosphere over the Tibetan Plateau. (2) A multiyear in situ L-Band microwave radiometry of land surface processes is used to develop a new microwave radiative transfer modeling system. This new system improves the modeling of brightness temperature in both horizontal and vertical polarization. (3) A multiyear (2001–2018) monthly terrestrial actual evapotranspiration and its spatial distribution on the Tibetan Plateau is generated using the surface energy balance system (SEBS) forced by a combination of meteorological and satellite data. (4) A comparison of four large scale soil moisture products to in situ measurements is presented. (5) The trajectory of water vapor transport in the canyon area of Southeast Tibet in different seasons is analyzed, and (6) the vertical water vapor exchange between the upper troposphere and the lower stratosphere in different seasons is presented.
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Evaluation and Design of Noise Control Measures for a Pneumatic Nail GunJayakumar, Vignesh 02 June 2015 (has links)
No description available.
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