Colorimetric sensor for bad odor detection using automated color correction

Colorimetric sensors based on color-changing dyes offer a convenient approach for the quantitative measurement of gases. An integrated, mobile colorimetric sensor can be particularly helpful for occasional gas measurements, such as informal air quality checks for bad odors. In these situations, the main requirement is high availability, easy usage, and high specificity towards one single chemical compound, combined with cost-efficient production. In this contribution, we show how a well stablished colorimetric method can be adapted for easy operation and readout, making it suitable for the untrained end user. As an example, we present the use of pH indicators for the selective and reversible detection of NH3 in air (one relevant gas contributing to bad odors) using gas-sensitive layers dip coated on glass substrates. Our results show that the method can be adapted to detect NH3 concentrations lower than 1 ppm, with measure-to-result times in the range of a few minutes. We demonstrate that the color measurements can be carried out with the optical signals of RGB sensors, without losing quantitative performance

Le héros tragique dans le roman africain (l'exemple du Monde s'effondre du nigérian Chinua Achebe, Un piège sans fin du béninois Olympe Bhêly-Quenum, Le cercle des tropiques du guinéen Alioum Fantoure et Fumée noire du Burkinabe Boubakar Diallo)

L'objectif visé par cette étude est l'analyse de l'évolution sociale du héros tragique dans le roman africain. En centrant notre démarche sur l'interprétation socio-historique de ces quarte œuvres, nous nous sommes heurté à un constat selon lequel l'existence du héros tragique dans le roman africain, s'ouvre généralement sur un moment de bonheur avant de basculer tout d'un coup dans la catastrophe. Or ce passage de l'état de bonheur à l'état de malheur absolu n'est pas lié à une force suprasensible qu'est la fatalité. C'est au contraire l'histoire en tant que mouvement événementiel de la conscience humaine et le politique qui se substituent souvent à la fatalité pour conduire le héros dans la tragédie. Au-delà de l'analyse de la situation sociale du héros, nous avons élargi le champ de notre recherche à l'examen du style de chaque auteur ce qui nous a permis de recueillir les principaux traits du roman africain sur le plan esthétique.The aim of this study is the analysis of the tragic hero's social evolution in the African novel. By centering our step on socio-historical interpretation of these four novels, we encountered a report according to which the tragic hero's existence, in the African novel, generally begins, at one time of happiness before rocking suddenly in the catastrophe. However the passage of the state of happiness to the state of absolute misfortune is not related to a suprasensible force like fate. It is on the contrary, the history as a movement of events projected by the human conscience and the policy which often replaces fate to lead the hero's to a tragedy. Beyond the analysis of the hero's social condition, we widened the fields of our study to the examination of the style of each author what enabled us to collect the principal features of the African novel on the aesthetics one.PARIS13-BU Droit-Lettres (930792101) / SudocSudocFranceF

Improvement Methods for Colorimetric Gas Sensor for Use in Indoor Livestock Farming

Different published colorimetric sensors were investigated with the ultimate goal to develop a colorimetric sensor for a closed livestock farm, applicable in a rough environment. The methods were investigated to improve the lack of sensitivity, roughness, and reproduction of colorimetric sensors. The methods investigated varied from changing matrices, changing substrates, treatment of the substrates, and investigation of the distribution by camera of the chemical thin layer and investigation on temperature, water and cross interference of several other gases in the livestock gas matrix. Results showed that with changing several important parameters, other than only the choice of a color indicator results in a serious improvement of the sensor specification and an improved performance necessary for the rough circumstances in livestock farming

Colorimetric sensor for bad odor detection using automated color correction

Colorimetric sensors based on color-changing dyes offer a convenient approach for the quantitative measurement of gases. An integrated, mobile colorimetric sensor can be particularly helpful for occasional gas measurements, such as informal air quality checks for bad odors. In these situations, the main requirement is high availability, easy usage, and high specificity towards one single chemical compound, combined with cost-efficient production. In this contribution, we show how a well stablished colorimetric method can be adapted for easy operation and readout, making it suitable for the untrained end user. As an example, we present the use of pH indicators for the selective and reversible detection of NH3 in air (one relevant gas contributing to bad odors) using gas-sensitive layers dip coated on glass substrates. Our results show that the method can be adapted to detect NH3 concentrations lower than 1 ppm, with measure-to-result times in the range of a few minutes. We demonstrate that the color measurements can be carried out with the optical signals of RGB sensors, without losing quantitative performance

Dissipative dark solitons in a dc complex plasma

The observation of dark solitons in a three-dimensional dc complex plasma is presented. The experiments are performed using neon gas at a pressure of 18 Pa and melamine-formaldehyde particles with a diameter of 3.43 μm. The waves are excited by a short pulse produced by the circular electrical-manipulative electrode built in inside the discharge glass tube. The wave speed is measured to be of the order of 15 mm/s. The propagation time of the observed dark soliton is approximately 10–15 times longer than the damping time

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We perform an observational test on global oscillations in Be star circumstellar disks in the metal deficient environment of the SMC. According to the hybrid model of disk oscillations early-type Be stars require an optically thin line force to establish a density wave. The low metallicity in the SMC should therefore diminish or prevent the formation of disk oscillations in early-type Be stars. We present short wavelength range spectra around Hα of 48 Be stars in the young open cluster NGC 330 in the SMC. We find that the fraction of early-type Be stars in NGC 330 which host a global disk oscillation does not differ from the known fraction of Galactic field Be stars. This observational result is in contradiction to the theoretical prediction. We discuss several interpretations and propose a further observational test

Design, assembly and characterization of silicide-based thermoelectric modules

International audienceSilicides have attracted considerable attention for use in thermoelectric generators due mainly to low cost, low toxicity and light weight, in contrast to conventional materials such as bismuth and lead telluride. Most reported work has focused on optimizing the materials properties while little has been done on module testing. In this work we have designed and tested modules based on N-type magnesium silicide Mg2(Si-Sn), abbreviated MGS, and P-type Higher Manganese Silicide, abbreviated HMS. The main novelty of our module design is the use of spring loaded contacts on the cold side which mitigate the effect of thermal expansion mismatch between the MGS and the HMS. We report tests carried out on three modules at different temperatures and electric loads. At a hot side temperature of 405 °C we obtained a maximum power of 1.04 W and at 735 °C we obtained 3.24 W. The power per thermoelectric material cross section area ranged from 1 to 3 W cm-2. We used the modeling tool COMSOL to estimate efficiencies at 405 and 735 °C and obtained values of 3.7% and 5.3% respectively - to our knowledge the highest reported value to date for silicide based modules. Post-test examination showed significant degradation of the N-type (MGS) legs at the higher hot side temperatures. Further work is underway to improve the lifetime and degradation issues. © 2015 Elsevier Ltd