Gas Sensors
Mostrando 37-48 de 53 artigos, teses e dissertações.
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37. Síntese de poli(p-fenilenovinileno)s alcoxilados e sua aplicação em diodos emissores de luz e em sensores de gases / Synthesis of alkoxylated poly(p-phenylenevinylene)s and their application in light emitting diodes and in gas sensors
The present work describes the electrosynthesis of three polymers of the poly(p-phenylenevinylene) (PPV) family, having at least one long chain alkoxy group as substituent. These polymers were characterized by spectroscopic analyses (1H NMR, IR and UV-Vis), thermogravimetry (TG), size exclusion chromatography (SEC), cyclic voltammetry and electrically by cur
Publicado em: 2006
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38. ProduÃÃo de heterojunÃÃes de polianilina/silÃcio e nanofibras de polianilina para aplicaÃÃes em dispositivos hÃbridos
In this work we develop the methodology for the synthesis and fabrication of Polyaniline (PANI) â Silicon (Si) heterojunctions, with great potential for technological applications as sensors in different areas such as optics, ionizing radiation and gas detection. Besides, we were able to implement the electrospinnin technique with the goal of producing poly
Publicado em: 2006
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39. Pattern recognition in integrated sensors. / Reconhecimento de padrões em sensores integrados.
In this work, several methods for pattern recognition and signal processing were studied and applied, using data obtained from different experimental setup of the Electronic Nose. The signals were obtained from the array of conductive sensor into de Nose system, which worked under variable temperature condition. The signal analyses results were used to obtai
Publicado em: 2005
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40. EFFECTS AND APPLICATIONS OF NON-HOMOGENEOUS STRAINS IN BRAGG GRATINGS / EFEITOS E APLICAÇÕES DE DEFORMAÇÕES NÃO HOMOGÊNEAS EM REDES DE BRAGG
Fiber Bragg gratings (FBG) are modulations in the effective refractive index of optical fibers, introduced in a small length along the fiber core. Such components operate as narrow band reflective filters, that is, when illuminated by a broad-band light source, they reflect a narrow spectral band centered at a specific wavelength, the Bragg wavelength. This
Publicado em: 2005
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41. Processamento e caracterização de condutores de íons O2- a partir de cerâmicas BIMEVOX. / Processing and characterization of O2- ion conductors from BIMEVOX ceramics.
In this work, the processing of BIMEVOX family ceramics (ME-doped bismuth vanadate, ME =Cu2+, Fe3+ and Ti4+), obtained by precursor oxides fusion method was studied. The resulting powders were valued by X ray diffraction, atomic emission spectrometry, scanning and transmission electronic microscopy, and analyzed by particle size distribution. The obtained re
Publicado em: 2005
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42. FabricaÃÃo e caracterizaÃÃo elÃtrica de heterojunÃÃes de polianilina-silÃcio para aplicaÃÃo em dosimetria de radiaÃÃo gama
In this work a technique has been developed to fabricate high quality polyanilinesilicon heterojunction diodes for use as gas and/or ionizing radiation sensors. Polyaniline thin films (40 nm thick) produced by spin-coating on silicon substrates, were the active part of the junction structure. The devices presented excellent reproducibility of their electrica
Publicado em: 2004
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43. Classificador de qualidade de álcool combustível e poder calorífico de gás GLP. / Alcohol combustible quality and LPG gas calorific power classifier.
This work shows the results of a robust system development as an alternative to recognize the quality of an alcohol fuel vapor sample and Liquid Petrol Gas (LPG) heat power in an electric nose. Two experimental methodologies were implemented to extract the features of alcohol fuel vapor and LPG gas patterns. The first approach to process the data used an Fuz
Publicado em: 2004
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44. DESENVOLVIMENTO DE TRANSDUTORES A FIBRA ÓPTICA PARA COMPLETAÇÃO INTELIGENTE DE POÇOS / DEVELOPMENT OF OPTICAL FIBER TRANSDUCERS FOR INTELLIGENT WELL COMPLETION
Optical fibers are finding a growing range of new applications in the petroleum industry, which include, not only those already well established in telecommunications, but also in novel sensing technologies. Possibility of dense multiplexing, continuous distributed measurements, long distances between measurement points and electronic circuits, and explosion
Publicado em: 2004
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45. Uso de técnicas de Geoprocessamento e Sensoriamento Remoto no levantamento e integração de dados necessários a gestão ambiental dos campos de extração de óleo e gás do Canto do Amaro e Alto da Pedra no município de Mossoró - RN
The objective of this work is to identify, to chart and to explain the evolution of the soil occupation and the envirionment vulnerability of the areas of Canto do Amaro and Alto da Pedra, in the city of Mossoró-RN, having as base analyzes it multiweather of images of orbital remote sensors, the accomplishment of extensive integrated works of field to a Geo
Publicado em: 2004
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46. Efectos de la exposición a vacío y aire de películas de SnO2 con distinto espesor
Gas sensors based in semiconductor oxides show a change in the resistance when they are exposed to certain gaseous atmospheres. In this paper, the influence on the sensor electrical resistance with the film thickness in vacuum and air are studied. The conduction process is analyzed considering the existence of Schottky potential barriers at the grain boundar
Materials Research. Publicado em: 2003-12
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47. Improving the power consumption in pneumatic conveying systems by a daptive control of the flow regime
The pneumatic conveying of solids in a gas stream is a recurrent process in petrochemical industries. However, due to practical limitations the majority of existing systems have capacities ranging from 1 to 400 tones per hour over distances less than 1000 m, mainly because of a high power consumption per transported unit mass. More specifically, to avoid the
Journal of the Brazilian Society of Mechanical Sciences and Engineering. Publicado em: 2003-12
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48. A silicon-polymer heterostructure for sensor applications
We report the development and characterization of high quality polyaniline-silicon heterojunction diodes appropriated for use as gas and/or ionizing radiation sensors. Polyaniline thin films 40 nm thick are an active part of the junction structure, that presents excellent electrical characteristics, with rectifying ratio of 50,000 at ± 1.0 Volt bias. The de
Brazilian Journal of Physics. Publicado em: 2002-06