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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.
11

Development of Free-Standing Interference Films for Paper and Packaging Applications

Holmqvist, Johan January 2008 (has links)
The newfound capability of creating moisture sensitive interference multilayered thin films (MLTFs) comprising microfibrillated cellulose and polymers has not previously been possible to implement on surfaces other than silicon wafer strips. Being able to incorporate interference MLTFs on fibre-based materials would introduce the possibility for new applications within authentication, sensing and customer attraction for the paper and packaging industry. By using trichloro (1H, 1H, 2H, 2H-perfluorooctyl) silane we were able to hydrophobically modify silicon substrates, enabling interference MLTF lift-off and thus the creation of free-standing MLTFs of approximately 400 nm thickness. Contact dried MLTFs approximately 250 nm thick, were successfully transferred to copy- and filter paper as well as to cellulose-based dialysis membranes. We can also report on the successful synthesis of interference MLTFs directly on a fibre composite material and on aluminium. Initial tests of a method to quantify the pull-off conditions of the MLTFs from the fluorinated surfaces using the Micro Adhesion Measurement Apparatus showed promising results.
12

DEFINIÇÃO DE ZONAS DE MANEJO EM LAVOURAS AGRÍCOLAS A PARTIR DE MAPAS DE PRODUTIVIDADE: ESTUDO DE CASO / FIELD PRODUCTIVITY EVOLUTIVE ANALYSIS

Barato, Márcio Adair 26 September 2014 (has links)
Based on productivity maps and data analysis it is possible for the producer to check and act over the low yielding areas, maximizing the final productivity that way. This paper intents to show the importance of the usage of precision agriculture maps on farms in order to help farmers to determine low yielding areas and act over it, improving productivity. This paper and the generated maps referred during the text were made using John Deere equipment and AMS (Agricultural Management Solutions). The studied area is a 19ha (190.000m²) total area, located at Faxinal, Paraná state. Five maps were analyzed totaling a 3 years range period of samples that were used later for interpolation. The interpolations and adjustments done were made using Apex® and CR Campeiro® software. The output of this interpolation is a single map that shows some tendencies for some areas to present low, medium and high yield. Those regions represent 5,95%, 86,25% and 7,80% respectively. This map is a base for the final analysis that will provide information to develop and increase productivity in low yielding areas. / Com base nos mapas de produtividade e as análises realizadas dos locais proporciona ao produtor rural agir pontualmente nestas áreas de baixa produtividade para maximizar sua produção. Este trabalho demonstra a importância da agricultura de precisão em utilizar os mapas de produtividade nas propriedades rural para ajudar a determinar pontos de baixa produtividade nas áreas colhidas, desta forma possibilita ser realizada análise destes locais para determinar qual é o fator que está gerando esta baixa produtividade. Para o desenvolvimento deste trabalho e geração dos mapas de produtividade foi utilizado o sistema de Solução em Gerenciamento Agrícola (AMS) e equipamentos da John Deere. A área do estudo é de 19 ha (190.000 m²) localizados no município de Faxinal - PR obteve-se desta área, mapas de produtividade de um período de três anos totalizando cinco mapas, que foram utilizados para realizar a interpolação. Para a realização da interpolação e ajustes dos mapas utilizaram-se os programas Apex® e CR Campeiro®, o resultado final desta interpolação foi a geração do mapa mostrando as zonas de manejo da área de estudo onde, no decorrer deste período, a produtividade manteve uma tendência nas regiões de baixa, média e alta produtividade do talhão, estas regiões representaram 5,95%, 86,25% e 7,80% respectivamente. Com base no mapa com as áreas de zona de manejo possibilitará a análise das regiões menos produtivas do talhão para maximizar a produção.
13

Vliv vlhkosti paliva na parametry regulace kotle / Impact of Fuel Moisture on Parameters of Boiler Regulation

Kiša, Michal January 2014 (has links)
The work deals with the verification of functionality of moisture content sensors MCT460-WP from the company Process sensors to measure fuel and products from biomass. The sensor is located on one of the Vyncke company boilers. In the first part of thesis are introduced basic issues of biomass. Thesis also generally describes the control and dynamics behaviour of biomass boilers and the effect of input parameters on the output parameters. The last part deals with comparing and analysing measured values with the calculated values and effects of moisture content changes on the output parameters of the boiler. As the last issue is loaded conceptual design based on on-line moisture sensing and inclusion of auxiliary fuel control into the existing system in order to stabilize the processes in the combustion chamber and output parameters. This should result in lower financial demands during boiler operation.
14

[en] RAIN VS. MOISTURE RELATIONSHIP IN UNSATURATED SOILS / [pt] RELAÇÃO CHUVA VS. UMIDADE EM SOLOS NÃO SATURADOS

MARCELA STRONGYLIS 21 June 2021 (has links)
[pt] O propósito do trabalho é avaliar a viabilidade técnica do uso de sondas tipo TDR e tensiômetros no monitoramento de encostas não saturadas. Com tais instrumentos, objetiva-se monitorar a variação da sucção mátrica e da umidade no solo em períodos chuvosos, visando aperfeiçoar os sistemas de alerta usados em áreas de risco e, consequentemente, minimizar perdas materiais e humanas. Para as medições, foram instalados uma estação meteorológica (munida de um pluviômetro, um datalogger, uma placa solar e uma antena para a transmissão de dados via internet), quatro sensores de umidade tipo TDR e um tensiômetro de alta capacidade em uma encosta localizada a montante da Faculdade de Medicina de Petrópolis, cidade da região serrana do estado do Rio de Janeiro. Foram registrados cerca de três meses de dados das sondas tipo TDR e, por conta de uma pane elétrica, apenas treze dias de dados do tensiômetro. As sondas tipo TDR apresentaram tempos de resposta rápidos, com nítidos aumentos de umidade volumétrica com o início de um evento chuvoso. Elas também apresentaram sensibilidade adequada para serem utilizadas em sistemas de alerta, sendo capazes de registrar alterações de umidade volumétrica com pequenos volumes de chuva. As curvas características encontradas através de ensaios de papel filtro mostraram um bom paralelo entre as sucções medidas diretamente pelo tensiômetro e aquelas obtidas indiretamente pelas sondas tipo TDR, através da conversão das umidades volumétricas em sucção. / [en] The purpose of this work is to evaluate the technical feasibility of using TDR probes and tensiometers to monitor unsaturated slopes. The objective is to monitor with these instruments the variation of matric suction and soil moisture during rainy periods, aiming to improve the warning systems used in hazardous areas and, consequently, to minimize human and material loss. For the measurements, a meteorological station (equipped with a rain gauge, a datalogger, a solar panel and an antenna for data transmission via internet), four TDR-type humidity sensors and a high capacity tensiometer were installed in a slope located in the University of Medicine of Petrópolis, city of the mountainous region of the state of Rio de Janeiro. Approximately three months of data were collected from the TDR probes and only thirteen days of tensiometer data due to a power outage. TDR-type probes showed fast response time, with clear increases in volumetric humidity with the beginning of a rainfall event. They also showed adequate sensitivity to be used in warning systems, being able to register changes in volumetric humidity with small precipitation amounts. The characteristic curves found by the filter method showed a good correlation with the suctions measured directly by the tensiometer and those obtained indirectly by the TDR probes, by converting the volumetric humidity into suction.
15

Synthesis of Conceptual Designs for Sensors

Sarkar, Biplab January 2015 (has links) (PDF)
National Programme on Micro and Smart Materials and Systems (NPMASS) / A computer-aided technique is developed in this thesis to systematically generate concepts for sensors of a wide variety. A database of building blocks, based on physical laws and effects that capture the transduction rules underlying the working principles of sensors, has been developed to synthesize concepts. The proposed method uses the database to first create a concept-space graph and then selects concepts that correspond to paths in the graph. This is in contrast to and more efficient than existing methods, such as, compositional synthesis and graph-grammar synthesis, where solution paths are laid out first and then a concept-space graph is generated. The research also explores an approach for synthesis of concepts for closed-loop sensors, where a quantity is sensed indirectly after nullifying its effect by using negative feedback. These sensors use negative feedback to increase the dynamic range of operation without compromising the sensitivity and resolution. According to the literature, generation of un-interesting solutions is a major drawback of the building block-based synthesis approaches. In the proposed approach, this shortcoming is mitigated substantially by using some rules. For a number of the concepts generated, in the sensor problems attempted, we found that those concepts were already implemented in existing patents; thus emphasising the usefulness of the concepts produced. The synthesis approach proposed new, feasible sensor concepts, thereby indicating its potential as a stimulator for enhancing creativity of designers. Another important problem is to improve the robustness of designs. Robustness can be achieved by minimizing the side effects. Side effects are defined as unwanted effects that affect the intended working of the sensor. The research presents an algorithm that (a) predicts the potential side effects for the synthesized concepts of sensors; (b) aids in quantifying the magnitude of the side effects, thus helping the designer to predict the significant side effects; and (c) suggests ways to improve the robustness of the design.

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