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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
711

Estabilização de solos com cimentos pozolânicos de cinza de casca de arroz e de resíduo cerâmico. / Soil stabilization with pozzolanic cements produced by rice husk ash and ceramic wastes.

Alex Kenya Abiko 29 April 1987 (has links)
A questão central deste trabalho é demonstrar a viabilidade técnica e econômica da estabilização de solos com os cimentos pozolânicos de cinza de casca de arroz e de resíduo cerâmico. Para alcançar este objetivo o trabalho foi desenvolvido em duas etapas: a primeira referente ao desenvolvimento dos cimentos pozolânicos e a segunda referente à estabilização do solo propriamente dita. Em ambas as etapas adotou-se o critério da simplicidade e da possibilidade de utilização de equipamentos leves e de absorção de mão-de-obra não especializada. Os resultados técnicos e econômicos referentes ao cimento pozolânico de cinza de casca de arroz foram animadores; porém o mesmo não ocorreu com o cimento pozolânico de resíduo cerâmico que apresentou um desempenho em um patamar inferior. Quanto à estabilização de solos, os experimentos e a avaliação econômica efetuada mostram que a eficácia dos cimentos pozolânicos utilizados é limitada sendo difícil a obtenção de resultados comparáveis com o atualmente obtido com o cimento Portland. / The main scope of this work is to demonstrate the technical and economical viability of the soil stabilization with pozzolanic cements made from rice husk ash and waste bricks and tiles. In order to reach this objective the work has been developed in two stages: the first referes to the development of the pozzolanic cement and the second one referes to the soil stabilization. In both these stages the criteria that has been adopted was of the simplicity, of the use of light equipments and of non skilled labour. The technical and economical results referring to the rice husk ash pozzolanic cement were encouraging; but the same was not the case with the waste bricks and tiles pozzolanic cement that had an inferior performance. As regards the soil stabilization, the tests and the economical evaluation show that the efficiency of the pozzolanic cement is limited thus the results achieved are not as good as of the Portland cement.
712

Effect of hydrogen addition and burner diameter on the stability and structure of lean, premixed flames

Kaufman, Kelsey Leigh 01 May 2014 (has links)
Low swirl burners (LSBs) have gained popularity in heating and gas power generation industries, in part due to their proven capacity for reducing the production of NOx, which in addition to reacting to form smog and acid rain, plays a central role in the formation of the tropospheric ozone layer. With lean operating conditions, LSBs are susceptible to combustion instability, which can result in flame extinction or equipment failure. Extensive work has been performed to understand the nature of LSB combustion, but scaling trends between laboratory- and industrial-sized burners have not been established. Using hydrogen addition as the primary method of flame stabilization, the current work presents results for a 2.54 cm LSB to investigate potential effects of burner outlet diameter on the nature of flame stability, with focus on flashback and lean blowout conditions. In the lean regime, the onset of instability and flame extinction have been shown to occur at similar equivalence ratios for both the 2.54 cm and a 3.81 cm LSB and depend on the resolution of equivalence ratios incremented. Investigations into flame structures are also performed. Discussion begins with a derivation for properties in a multicomponent gas mixture used to determine the Reynolds number (Re) to develop a condition for turbulent intensity similarity in differently-sized LSBs. Based on this requirement, operating conditions are chosen such that the global Reynolds number for the 2.54 cm LSB is within 2% of the Re for the 3.81 cm burner. With similarity obtained, flame structure investigations focus on flame front curvature and flame surface density (FSD). As flame structure results of the current 2.54 cm LSB work are compared to results for the 3.81 cm LSB, no apparent relationship is shown to exist between burner diameter and the distribution of flame surface density. However, burner diameter is shown to have a definite effect on the flame front curvature. In corresponding flow conditions, a decrease in burner diameter results a broader distribution of curvature and an increased average curvature, signifying that compared to the larger 3.81 cm LSB, the flame front of the smaller burner contains tighter, smaller scale wrinkling.
713

A Deep Reinforcement Learning Approach for Robotic Bicycle Stabilization

January 2020 (has links)
abstract: Bicycle stabilization has become a popular topic because of its complex dynamic behavior and the large body of bicycle modeling research. Riding a bicycle requires accurately performing several tasks, such as balancing and navigation which may be difficult for disabled people. Their problems could be partially reduced by providing steering assistance. For stabilization of these highly maneuverable and efficient machines, many control techniques have been applied – achieving interesting results, but with some limitations which includes strict environmental requirements. This thesis expands on the work of Randlov and Alstrom, using reinforcement learning for bicycle self-stabilization with robotic steering. This thesis applies the deep deterministic policy gradient algorithm, which can handle continuous action spaces which is not possible for Q-learning technique. The research involved algorithm training on virtual environments followed by simulations to assess its results. Furthermore, hardware testing was also conducted on Arizona State University’s RISE lab Smart bicycle platform for testing its self-balancing performance. Detailed analysis of the bicycle trial runs are presented. Validation of testing was done by plotting the real-time states and actions collected during the outdoor testing which included the roll angle of bicycle. Further improvements in regard to model training and hardware testing are also presented. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2020
714

Stabilization of Horseradish Peroxidase Using Epoxy Novolac Resins for Applications with Microfluidic Paper-Based Analytical Devices

Chaplan, Cory A. 01 June 2014 (has links)
Microfluidic paper-based analytical devices (microPADs) are an emerging platform for point-of-care diagnostic tests for use by untrained users with potential applications in healthcare, environmental monitoring, and food safety. These devices can be developed for a multitude of different tests, many of which employ enzymes as catalysts. Without specialized treatment, some enzymes tend to lose their activity when stored on microPADs within 48 hours, which is a major hurdle for taking these types of devices out of the laboratory and into the real world. This work focused on the development of simple methods for stabilizing enzymes by applying polymers to chromatography paper. The longterm stabilization was exlored and SU-8 of various concentrations was found to stabilize horseradish peroxidase for times in excess of two weeks. A variety of microPAD fabrications, enzyme dispensing methods, and substrate delivery techniques were explored.
715

Návrh optimálního promíchávání velkokapacitních vyhnívacích nádrží / Design of optimal mixing of large-scale digesters

Bradáč, Antonín January 2017 (has links)
The aim of this diploma thesis is an optimal method of mixing of the digester with consideration to the uniform mixing of the whole volume, ensuring the quality process conditions for the anaerobic fermentation and the maximum yield and quality of the produced biogas. First chapters describe the basic design parameters, general calculations and the principles for design of individual types of mixers, supplemented by practical examples of mixing large capacity tanks. The work introduces the problem of sludge formation at the sewage treatment plant with an emphasis on sludge treatment and the processes which take place inside the fermenter. Various types of design of anaerobic sludge stabilization digester were introduced. Also ways of their operation, which are necessary for the quality of the fermentation, were presented. In the next chapters, various ways of mixing high-capacity digester tanks and experience from the operation of selected treatment plants were described. According to the theoretical research part of this thesis, several types of mixing equipment was designed for the experimental digestion tank built at the Institute of Process Engineering which is used for research work with mixers. Measurement of the selected pneumatic mixing method was performed on the experimental tank and the findings were evaluated.
716

Sanace sesuvu silničního tělesa / Stabilization of landslide on road embankment

Kořínková, Jana January 2018 (has links)
The topic of this Master`s thesis is to design stabilization of road embankment, which is between Brno-Chrlice and Brno-Holásky. Aim of this thesis is finding acceptable solution of problem including finding cause of fault and describing other possible options. Solution will be design in GEO5. Thesis is completed with procedure in pile installation and drawing documentation.
717

Vliv cviků mobility v offline a online prostředí na subjektivní vnímání bolesti zad / Effect of mobility exercises in offline and online environment on subjective perception of back pain

Burgetová, Dominika January 2021 (has links)
Title: Effect of mobility exercises in offline and online environment on subjective perception of back pain Objectives: The main goal of this work was to determine whether the onset of daily mobility contributes to the reduction of individual's back pain perception. Within the work the results between the offline and online group was compared. Methods: The diploma thesis has the character of qualitative research, where case study of 20 probands was applied. Online input and output questionnaires were compiled to obtain data, which respondents filled in at the beginning and end of the intervention. Results: The research included 11 women and 9 men aged 21 - 44 years. Individuals have mostly sedentary jobs and some of them play recreational sports in their free time. At the end of the intervention, all individuals showed an improvement on the scale of the pain intensity, when the perceived back pain was alleviated or disappeared. The offline group performed better than the online group. Conclusion: The study confirmed that the inclusion of daily mobility contributes to the reduction of subjectively perceived back pain. It confirmed that exercising in offline lessons is more effective than in an online environment. Keywords: mobility, back pain, diaphragmatic breathing, torso stabilization, DNS
718

Onboard Video Stabilization for Unmanned Air Vehicles

Cross, Nicholas Stewart 01 June 2011 (has links)
Unmanned Air Vehicles (UAVs) enable the observation of hazardous areas without endangering a pilot. Observational capabilities are provided by on-board video cameras and images are relayed to remote operators for analysis. However, vibration and wind cause video camera mounts to move and can introduce unintended motion that makes video analysis more difficult. Video stabilization is a process that attempts to remove unwanted movement from a video input to provide a clearer picture. This thesis presents an onboard video stabilization solution that removes high-frequency jitter, displays output at 20 frames per second (FPS), and runs on a Blackfin embedded processor. Any video stabilization algorithm will have to contend with the limited space, weight, and power available for embedded systems hardware on a UAV. This thesis demonstrates how architecture-specific optimizations improve algorithm performance on embedded systems and allow an algorithm that was designed with more powerful computing systems in mind to perform on a system that is limited in both size and resources. These optimizations reduce the total clock cycles per frame by 157 million to 30 million, which yields a frame rate increase from 3.2 to 20 FPS.
719

Využití klasických analytických technik při kontrole základních parametrů kvality vína / Use of standard analytical technics by the inspection of basic parameters of wine quality

Hánová, Kristína January 2009 (has links)
Standard analytical technics are used by the inspection of basic parameters of wine quality in the prezented graduation theses. Theoretical patr contains short description of viniculture history. Description of elementary bunch of grapes stage of processing and wine production from stum pressing untill bottling follow. There is short description of wine diseases and wine defekt, too. Attention paid to quality assessment. Experimental part is divided to 2 parts. The first part contains determination of four wines qualitative parameters value. Analysis are focused on final wine processing phase, e.g. wine filtration, wine clarification and stabilisation, wine bottling. Data evaluation of these four sort of wine get no basic parameters differences. Parameters value differences are small but fundamentaly conducive to wine enhance quality.
720

Stabilizace sekvence snímků bez snížení jejich rozlišení / Stabilization of image sequence without decrement of its resolution

Otruba, Vítězslav January 2010 (has links)
The shake that affects the video camera during taking of the footage degrades the level of the viewer experience. This article contains the design of the method that stabilizes the stored footage and fills in the gaps in the separate frames, so the picture resolution remains the same after the process.

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