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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.
91

INNOVATIVE COATINGS FOR EFFICIENT BUILDING THERMAL MANAGEMENT

Ziqi Fang (17358838) 09 November 2024 (has links)
<p dir="ltr">The first part of this work proposes a solution for the challenge discussed section 1.2.1 by designing and validating a radiative cooling paint that is durable when attached to a substrate, and biodegradable when dispersed into the environment. Said paint also features high solar spectrum reflectivity and high sky window (8-13 microns) emissivity which enables it to achieve sub-ambient surface temperature throughout the day, even under direct sunlight. Full-biodegradation is observed in lab-based biodegradability testing using a comparison test between a biodegradable sample and a non-biodegradable sample. </p><p dir="ltr">The second part of this work demonstrates an innovative dual-layer design featuring a thin layer of leuco dye based thermochromic paint applied on top of a thick layer of BaSO4-based ultra-white daytime radiative cooling paint. This design utilizes thermochromism, a temperature-activated reversible chemical reaction that drastically changes the absorptivity of the affected media. In this work, the leuco dye-based thermochromic top layer effectively works as an autonomous thermal switch that, when temperatures are high and cooling is required, it switches to a "colorless state," enabling the radiative cooling basecoat to reflect incoming sunlight and emit radiatively, effectively cooling the surface. Conversely, when temperatures are low and heating is needed, the thermochromic top layer activates and transforms into an absorbing surface. This activation blocks the reflective and emitting bottom layer from radiatively cooling the surface, and instead absorbs incoming radiation to heats up the surface.</p>
92

Proměny zobrazení československých pilotů v české filmové tvorbě / Image transformation of czechoslovakian pilots in selected czech films

Janů, Adéla January 2017 (has links)
This thesis analyses image of Czechoslovakian pilots in local film production. It focuses on films about pilots from Second World War and pilots from Czechoslovak people's army. The aim of thesis is to define main characteristics of military pilots in selected films and compare their transformation through time. Analytic part will use visual, semiotic, discursive and narrative analysis concept as theoretical framework. Thesis works on the presumption that image transformation was highly influenced by historical and political development of country. It assumes that pilots from Second World War were portrayed positively in late 1960s and after year 1989 and pilots from Czechoslovak people's army were favored in era of normalization, particularly in 1970s and 1980s.
93

A passive night-sky radiation system

Joubert, Gideon Daniel 12 1900 (has links)
Thesis (MEng) -- Stellenbosch University, 2014. / ENGLISH ABSTRACT: A passive night-sky radiation cooling system consists of a radiation panel and a cold water storage tank. The stored cold water may be used to cool a room during the day time, particularly in summer. In this thesis a theoretical and mathematically sound simulation model is developed. An experimental set-up was constructed and subsequently used to show that the theoretical model effectively simulates the transient heating or cooling response of the system. It is shown that under South African conditions the typical heat emitting rate during the night is 55 W/m2. After the heat has been removed from the water, it is stored in a cold water tank from where it is circulated through a natural convector during the day time to absorb heat from the room. The experiment extracted a minimum of 102 W/m3 of heat from a 1.87 m3 galvanized steel room while a brick room with a volume of 120 m3 requires 22.7 W/m3. Additional to cooling, the system during the day, absorbed an average of 362 W of energy and heated 68 l of water from 24 °C to 62 °C within an 8-hour period. The system achieved similar results during winter conditions and the experiment confirms that the system is capable of operating without a control system. Therefore it is recommended that renewable energy-conscious designers pay more attention to the use of night-sky radiation cooling in future. / AFRIKKANSE OPSOMMING: en ’n koue water tenk. Die sisteem kan gebruik word om ’n vertrek gedurende die dag te verkoel, veral in die somer, deur gebruik te maak van die gestoorde verkoelde water. In hierdie tesis word ’n teoretiese en sinvolle wiskundige simulasie model ontwikkel. ’n Eksperimentele stelsel is gebou en vervolgens gebruik om te bewys dat die teoretiese model die veranderende verkoeling en verwarming van die stelsel effektief simuleer. Die tesis dui aan dat onder Suid Afrikaanse toestande daar ’n hitte vrystellings tempo van 55 W/m2 is gedurende die nag. Nadat die water verkoel is, word dit gestoor in die koue water tenk vanwaar dit deur ’n natuurlike konvektor sirkuleer en gedurende die dag warmte vanuit die vertrek onttrek. Die eksperiment het ’n minimum van 102 W/m3 warmte vanuit die galvaniseerde 1.87 m3 vertrek geabsorbeer, terwyl ’n baksteen vertrek van 120 m3, 22.7 W/m3 verkoeling benodig. Bykomstig tot die verkoelingstelsel verhit die sisteem 68 l water vanaf 24 °C to 62 °C gedurende ’n 8-uur periode in die dag, dus word 362Wenergie geabsorbeer. Die sisteem is ook getoets tydens winter toestande, die resultate was dieselfde as wat in die somer verkry is. Verder is daar ook bewys dat die sisteem sonder enige beheerstelsel kan funksioneer. Verder word daar aanbeveel dat hernubare energie bewuste ontwerpers in die toekoms meer aandag aan ruimte straling verkoeling skenk.
94

Abundance and habitat relationships of breeding birds in the Sky Islands and adjacent Sierra Madre Occidental of northwest Mexico

Flesch, Aaron D., Gonzalez Sanchez, Carlos, Valenzuela Amarillas, Javier 06 1900 (has links)
The Sierra Madre Occidental and neighboring Madrean Sky Islands span a large and biologically diverse region of northwest Mexico and portions of the southwestern United States. Little is known about the abundance and habitat use of breeding birds in this region of Mexico, but such information is important for guiding conservation and management. We assessed densities and habitat relationships of breeding birds across Sky Island mountain ranges in Mexico and adjacent portions of the Sierra Madre from 2009 to 2012. We estimated densities at multiple spatial scales, assessed variation in densities among all major montane vegetation communities, and identified and estimated the effects of important habitat attributes on local densities. Regional density estimates of 65% of 72 focal species varied significantly among eight montane vegetation communities that ranged from oak savannah and woodland at low elevations to pine and mixed-conifer forest at high elevations. Greater proportions of species occurred at peak densities or were relatively restricted to mixed-conifer forest and montane riparian vegetation likely because of higher levels of structural or floristic diversity in those communities, but those species were typically rare or uncommon in the Sky Islands. Fewer species had peak densities in oak and pine-oak woodland, and species associated with those communities were often more abundant across the region. Habitat models often included the effects of broadleaf deciduous vegetation cover (30% of species), which, together with tree density and fire severity, had positive effects on densities and suggest ways for managers to augment and conserve populations. Such patterns combined with greater threats to high-elevation conifer forest and riparian areas underscore their value for conservation. Significant populations of many breeding bird species, including some that are of concern or were not known to occur regionally or in mountain ranges we surveyed, highlight the importance of conservation efforts in this area of Mexico.
95

Contribuições de um curso de formação docente em astronomia para a prática de ensino de professores da educação básica /

Cavalcanti, Cleberson José January 2019 (has links)
Orientador: Roberto Nardi / Resumo: Este estudo se insere dentre as investigações que vêm sendo conduzidas no âmbito do Grupo de Pesquisa em Ensino de Ciências (GPEC), UNESP, Campus de Bauru, São Paulo, Brasil, que têm se preocupado em reduzir o distanciamento entre a produção acadêmica da área e os saberes e práticas de licenciandos e professores em exercício da Educação Básica. Esta pesquisa busca avaliar as possíveis contribuições oferecidas por um curso de formação docente em Astronomia introdutória na prática de ensino de um grupo de professores do Ensino Fundamental da Educação Básica, da rede pública de ensino de Bauru (SP), bem como investigar sobre as dificuldades e os desafios dos professores durante a implementação do material didático, no formato de um diário escolar - O Diário do Céu -, originalmente elaborado para a realidade do Hemisfério Norte (Il Diario del Cielo), particularmente para a localidade de Roma, Itália, e adaptado para a faixa tropical do Hemisfério Sul, em especial para a localidade de Bauru, São Paulo, Brasil, para o trabalho com conceitos de fenômenos astronômicos, a partir do referido curso de formação dos professores envolvidos na pesquisa. O percurso metodológico de constituição e análise dos dados obtidos é descrito, discutido e analisado. A análise dos dados constituídos nesta pesquisa foi empregada segundo concepção de linguagem e leitura consolidada a partir da teoria e procedimentos da Análise de Discurso. Dentre os resultados alcançados, destacaram-se dados que mostram a... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: This present study is inserted among the investigations that have been conducted in the area of “Grupo de Pesquisa em Ensino de Ciências”, GPEC ( Research Group in Science Teaching), Unesp, Bauru Campus of Bauru, São Paulo, Brazil, with the main goal of reducing the distance between the academic production and the knowledge and practice of graduates and teachers of “Educação Básica” (Elementary and High School Education). This research aims at evaluating the possible contributions offered by a Teachers’Training group in Introductory Astronomy in the Elementary and High Schools from the Public Network in Bauru, as well as to investigate about the difficulties and challenges during the implementation of the didactical material in the format of a school diary – The Diary of the Sky – originally elaborated for the North Hemisphere reality (Il Diario del Ciclo II), particularly for the city of Rome, Italy, and adapted for the tropical layer of the South Hemisphere, specially for the city of Bauru, São Paulo, Brazil, for the work with concepts of Astronomy Phenomena, from the referred course of Teacher”s Training involved in the research. The methodology is based on constitution and analysis of the data obtained , described, discussed and analysed. Data collection was performed through focus groups (and later transcription for Discourse Analysis), semi-structured questionnaires and the completion of each teacher's diary.It was used according to the conception of Language and Readin... (Complete abstract click electronic access below) / Mestre
96

A observação do céu nos livros didáticos de ciências aprovados no PNLD/2017 / The observation of the sky in the textbook of sciences approved in the PNLD/2017

Costa, Gleice Kelen Dornelles 07 June 2018 (has links)
A atividade de observação do céu remonta à antiguidade e sua presença na educação básica é defendida por distintos pesquisadores. O caráter observacional pode ser uma estratégia didática para que o aluno amplie a percepção do seu entorno astronômico, sendo capaz de reconhecer fenômenos que fazem parte de seu cotidiano, com ou sem o uso de instrumentos. No entanto, as atividades de observação direta do céu requerem tempos (duração e horários das atividades) e espaços (a céu aberto, fora da sala de aula) que fogem do sistema tradicional escolar, além da necessidade de condições atmosféricas para tal. Esta pesquisa visa compreender a natureza das atividades de observação do céu no Ensino Fundamental II, na disciplina de Ciências, por meio da análise de livros didáticos. Este material didático constituiu-se como um elemento de grande importância dentro do contexto escolar, influenciando o trabalho do professor e acompanhando os alunos em suas atividades, tanto na escola como em casa. Foram analisadas nove coleções de livros didáticos de ciências distribuídos nacionalmente através do Programa Nacional do Livro Didático/2017. A análise foi subsidiada pela elaboração de um conjunto de elementos considerados fundamentais para a construção de uma atividade de observação do céu na escola, presentes nos trabalhos de pesquisadores da área de educação em Astronomia. Esses elementos estruturam o conjunto de atividades que envolvem a observação em seus distintos momentos: antes, durante e após a atividade de observação do céu. Desta forma, foram construídas oito categorias que subsidiaram a análise: Material, Pré-observação, Estratégias para observar e acompanhar astros ou fenômenos, Natureza da observação, Pós-observação, Espaço, Subsídios e Complementos. Na análise, percebeu-se que tópicos de Astronomia estão concentrados nos livros de sexto ano, e que ocupam uma parte considerável do material didático desta série, considerando que estão incluídos conteúdos de outras áreas do conhecimento como Biologia, Física, Geociências, Química. Tópicos de Astronomia desaparecem no sétimo e oitavo anos, retornando no nono ano, em geral, com outras características dentro de Gravitação. As propostas didáticas de observação aparecem quase que exclusivamente no sexto ano e são centradas em curtos períodos de tempo, dificultando a percepção de fenômenos cíclicos promovendo observações contemplativas. Além disso, as atividades geralmente são propostas para serem realizadas fora do espaço escolar, dificultando a participação in loco do professor, necessitando para tal um maior detalhamento da proposta e uma grande autonomia discente. Ainda que as atividades de observação estejam presentes nos LD elas ainda estão distantes das propostas feitas pelos pesquisadores da área que sugerem observações sistemáticas para melhor compreensão, tornando-as experiências próprias, em que a aprendizagem ocorre no tempo do fenômeno e também próprio de cada aluno. / Observation of the cosmos dates back to antiquity, and its perpetual presence in basic education is defended by researchers. The observational character can be used as a didactic strategy for the student to enhance the perception of their astronomical environment, being able to recognize phenomena that are part of their daily life, either with or without the use of instruments. However, direct sky observation activities require time (times and schedules of events) and locations (outdoors, outside the classroom) that contrast from the traditional school system, in addition to required atmosphere conditions. This research intends to analyze and understand the nature of the activities when observing the sky while in Elementary School, in the discipline of Sciences for the final years, through textbook study. This material constitutes an element of significant importance within the school context, influencing the work of the teacher and student activity, both at school and at home. Nine collections of science textbooks, distributed nationally through the National Textbook Program / 2017, were analyzed. The analysis was subsidized by the construction of a set of elements considered fundamental for the implementation of an activity of observation of the sky in the school, present in the works of researchers in the area of education in Astronomy. These elements make up the structure of the set of observational activities that range in time from moments before, during and after the sky observation activity. In this way, eight categories were constructed and subsidized the analysis: Material, Pre-observation, Strategies to observe and follow stars or phenomena, Nature of observation, Post-observation, Space, Subsidies and Complements. In the analysis, it was noticed that topics of Astronomy are concentrated in the books of sixth year, and that they occupy a considerable bulk of it, while noting that contents of other areas of education include Biology, Physics, Geosciences, Chemistry. Astronomy topics disappear in the seventh and eighth years and return in the ninth year, usually within Gravitation. The presence of observation are also implemented almost exclusively in the sixth year, which are focused on short periods of time, thereby making it difficult to perceive cyclical phenomena promoting contemplative observations. In addition, these exercises are usually intended to be carried out outside of the school grounds, making it difficult for the teacher to participate, and requiring greater student autonomy. Although the activities of observation are present in the LD, they are still far from the proposals made by the researchers of the area that suggest systematic observations for a better understanding, becoming the own experiences, in which the learning occurs in the time of the phenomenon and also own of each student
97

A observação do céu nos livros didáticos de ciências aprovados no PNLD/2017 / The observation of the sky in the textbook of sciences approved in the PNLD/2017

Gleice Kelen Dornelles Costa 07 June 2018 (has links)
A atividade de observação do céu remonta à antiguidade e sua presença na educação básica é defendida por distintos pesquisadores. O caráter observacional pode ser uma estratégia didática para que o aluno amplie a percepção do seu entorno astronômico, sendo capaz de reconhecer fenômenos que fazem parte de seu cotidiano, com ou sem o uso de instrumentos. No entanto, as atividades de observação direta do céu requerem tempos (duração e horários das atividades) e espaços (a céu aberto, fora da sala de aula) que fogem do sistema tradicional escolar, além da necessidade de condições atmosféricas para tal. Esta pesquisa visa compreender a natureza das atividades de observação do céu no Ensino Fundamental II, na disciplina de Ciências, por meio da análise de livros didáticos. Este material didático constituiu-se como um elemento de grande importância dentro do contexto escolar, influenciando o trabalho do professor e acompanhando os alunos em suas atividades, tanto na escola como em casa. Foram analisadas nove coleções de livros didáticos de ciências distribuídos nacionalmente através do Programa Nacional do Livro Didático/2017. A análise foi subsidiada pela elaboração de um conjunto de elementos considerados fundamentais para a construção de uma atividade de observação do céu na escola, presentes nos trabalhos de pesquisadores da área de educação em Astronomia. Esses elementos estruturam o conjunto de atividades que envolvem a observação em seus distintos momentos: antes, durante e após a atividade de observação do céu. Desta forma, foram construídas oito categorias que subsidiaram a análise: Material, Pré-observação, Estratégias para observar e acompanhar astros ou fenômenos, Natureza da observação, Pós-observação, Espaço, Subsídios e Complementos. Na análise, percebeu-se que tópicos de Astronomia estão concentrados nos livros de sexto ano, e que ocupam uma parte considerável do material didático desta série, considerando que estão incluídos conteúdos de outras áreas do conhecimento como Biologia, Física, Geociências, Química. Tópicos de Astronomia desaparecem no sétimo e oitavo anos, retornando no nono ano, em geral, com outras características dentro de Gravitação. As propostas didáticas de observação aparecem quase que exclusivamente no sexto ano e são centradas em curtos períodos de tempo, dificultando a percepção de fenômenos cíclicos promovendo observações contemplativas. Além disso, as atividades geralmente são propostas para serem realizadas fora do espaço escolar, dificultando a participação in loco do professor, necessitando para tal um maior detalhamento da proposta e uma grande autonomia discente. Ainda que as atividades de observação estejam presentes nos LD elas ainda estão distantes das propostas feitas pelos pesquisadores da área que sugerem observações sistemáticas para melhor compreensão, tornando-as experiências próprias, em que a aprendizagem ocorre no tempo do fenômeno e também próprio de cada aluno. / Observation of the cosmos dates back to antiquity, and its perpetual presence in basic education is defended by researchers. The observational character can be used as a didactic strategy for the student to enhance the perception of their astronomical environment, being able to recognize phenomena that are part of their daily life, either with or without the use of instruments. However, direct sky observation activities require time (times and schedules of events) and locations (outdoors, outside the classroom) that contrast from the traditional school system, in addition to required atmosphere conditions. This research intends to analyze and understand the nature of the activities when observing the sky while in Elementary School, in the discipline of Sciences for the final years, through textbook study. This material constitutes an element of significant importance within the school context, influencing the work of the teacher and student activity, both at school and at home. Nine collections of science textbooks, distributed nationally through the National Textbook Program / 2017, were analyzed. The analysis was subsidized by the construction of a set of elements considered fundamental for the implementation of an activity of observation of the sky in the school, present in the works of researchers in the area of education in Astronomy. These elements make up the structure of the set of observational activities that range in time from moments before, during and after the sky observation activity. In this way, eight categories were constructed and subsidized the analysis: Material, Pre-observation, Strategies to observe and follow stars or phenomena, Nature of observation, Post-observation, Space, Subsidies and Complements. In the analysis, it was noticed that topics of Astronomy are concentrated in the books of sixth year, and that they occupy a considerable bulk of it, while noting that contents of other areas of education include Biology, Physics, Geosciences, Chemistry. Astronomy topics disappear in the seventh and eighth years and return in the ninth year, usually within Gravitation. The presence of observation are also implemented almost exclusively in the sixth year, which are focused on short periods of time, thereby making it difficult to perceive cyclical phenomena promoting contemplative observations. In addition, these exercises are usually intended to be carried out outside of the school grounds, making it difficult for the teacher to participate, and requiring greater student autonomy. Although the activities of observation are present in the LD, they are still far from the proposals made by the researchers of the area that suggest systematic observations for a better understanding, becoming the own experiences, in which the learning occurs in the time of the phenomenon and also own of each student
98

Hlavu vzhůru. Výtvarný projekt pro mladší školní věk. (teoreticko - projektová práce) / Head up. Creative Project for Primary School Age.(theoretical - project thesis)

HAVLÍKOVÁ, Kristýna January 2019 (has links)
The presented theoretical and project diploma thesis was aimed at developing an art project named Head up, during the Art Education lessons in the first level of elementary school. It is structured in two parts, a theoretical and a practical one. The theoretical part provides a general insight into the problems of the sky and the cloud in visual arts and is followed by the project part which consists in eight proposed art lessons, description of the compositions and the didactic analysis of individual lessons. The diploma thesis is followed with pictorial annexes related to the theoretical part, photo documentation of lessons and proposed structured preparation.
99

On Active Secondary Suspension in Rail Vehicles to Improve Ride Comfort

Orvnäs, Anneli January 2011 (has links)
One way to make rail vehicles a competitive means of transportation is to increase running speed. However, higher speeds usually generate increased forces and accelerations on the vehicle, which have a negative effect on ride comfort. With conventional passive suspension, it may be difficult to maintain acceptable passenger comfort. Therefore, active technology in the secondary suspension can be implemented to improve, or at least maintain, ride comfort at increased vehicle speeds or when track conditions are unfavourable. This thesis describes the development of an active secondary suspension concept to improve ride comfort in a high-speed train. Firstly, an active lateral secondary suspension system (ALS) was developed, including dynamic control of the lateral and yaw modes of the carbody. Furthermore, quasi-static lateral carbody control was included in the suspension system in order to laterally centre the carbody above the bogies in curves at high track plane acceleration and hence to avoid bumpstop contact. By means of simulations and on-track tests, it is shown that the ALS system can offer significant lateral ride comfort improvements compared to a passive system. Two different control strategies have been studied—the relatively simple sky-hook damping and the multi-variable H∞ control—using first a quarter-car and then a full-scale vehicle model. Simulation results show that significant ride comfort improvements can be achieved with both strategies compared to a passive system. Moreover, H∞ control in combination with the carbody centring device is better at reducing the relative lateral displacement in transition curves compared to sky-hook damping. Secondly, an active vertical secondary suspension system (AVS) was developed, using simulations. Dynamic control of the vertical and roll modes of the carbody, together with quasi-static roll control of the carbody, show significant vertical ride comfort improvements and allow higher speeds in curves. Further, the AVS system compensates for negative ride comfort effects if the structural stiffness of the carbody is reduced and if the vertical air spring stiffness is increased. Finally, the two active suspension systems (ALS and AVS) were combined in simulations. The results show that both lateral and vertical ride comfort is improved with the active suspension concept at a vehicle speed of 250 km/h, compared to the passive system at 200 km/h. Further, active suspension in one direction does not affect the other direction. The ALS system has been included in two recent orders comprising more than 800 cars. / QC 20111205 / Gröna Tåget
100

The Examination of Hemispherical Photography as a means of obtaining In Situ Remotely Sensed Sky Gap Estimates in Snow-Covered Coniferous Environments

Redekop, Diane Evelyne 26 August 2008 (has links)
In remote sensing, the application determines the type of platform and scale used during air or space –borne data collection as the pixel size of the collected data varies depending on the sensor or platform used. Applications involving some cryospheric environments require the use of the microwave band of the electromagnetic spectrum, with snow water equivalent (SWE) studies making use of passively emitted microwave radiation. A key issue in the use of passive microwave remotely sensed data is its spatial resolution, which ranges from 10 to 25 kilometres. The Climate Research Branch division of the Meteorological Service Canada is using passive microwave remote sensing as a means to monitor and obtain SWE values for Canada’s varying land-cover regions for use in climate change studies. Canada’s diverse landscape necessitated the creation of a snow water equivalent retrieval algorithm suite comprised of four different algorithms; all reflecting different vegetative covers. The spatial resolution of small scale remotely sensed data does provide a means for monitoring Canada’s large landmass, but it does, however, result in generalizations of land-cover, and in particular, vegetative structure, which is shown to influence both snow cover and algorithm performance. The Climate Research Branch is currently developing its SWE algorithm for Canada’s boreal forest region. This thesis presents a means of successfully and easily collecting in situ remotely sensed data in the form of hemispherical photographs for gathering vegetative structure data to ground-truth remotely sensed data. This thesis also demonstrates that the Gap Light Analyzer software suite used for analyzing hemispherical photographs of mainly deciduous environments during the spring-fall months can be successfully applied towards cryospheric studies of predominantly coniferous environments.

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