Showing papers by "École Polytechnique de Montréal published in 1969"
TL;DR: In this article, Hougen-Watson method was used to determine the most probable model for the catalytic air oxidation of propylene to acrolein over a supported copper oxide catalyst.
Abstract: The catalytic air oxidation of propylene to acrolein over a supported copper oxide catalyst was investigated in a continuous stirred vessel reactor between 375° and 450°C at atmospheric pressure. The effect of temperature, ratio of oxygen to propylene in feed and total feed rate (or contact time) on the conversion of propylene and the yield of acrolein were determined. It was found that with an increase in temperature, ratio of oxygen to propylene and contact time, the yield drops considerably though conversion increases.
A study of the mixing characteristics of the stirred vessel reactor was carried out by following the conversion at various stirrer speeds.
The kinetic data obtained were tested to determine the most probable model by the Hougen-Watson method. The model that satisfactorily correlated the data describes the rate-controlling step as the surface reaction occurring between adsorbed propylene, a vacant site and oxygen in the gas phase. The following Hougen-Watson type rate equation has been proposed
The constants in the rate equation have been expressed as a function of temperature.
On a etudie l'oxydation catalytique a l'air du propylene en acroleine, en utilisant un catalyseur d'oxyde de cuivre comme support, dans un vaisseau-reacteur soumis a une agitation continue et a la pression atmospherique entre 375° et 450°C. On a determine l'effet de la temperature, du rapport entre l'oxygene et le propylene dans l'alimentation et de la vitesse de l'alimentation totale (ou duree de contact) sur la transformation du propylene et le rendement d'acroleine obtenu. On a trouve qu'en augmentant la temperature, le rapport entre l'oxygene et le propylene et le temps de contact, le rendement diminuait considerablement pendant que la transformation augmentait.
On a fait une etude des proprietes du vaisseau-reacteur soumis a l'agitation qui affectent le melange, en suivant la transformation qui se fait a differentes vitesse de l'agitateur.
On a experimente les resultats cinetiques qu'on avait obtenus pour determiner par la methode Hougen-Watson quel serait le modele le plus probable. Le modele qui a permis d'etablir une correlation satisfaisante entre les donnees depeint le reglage de la vitesse comme la reaction superficielle qui se produit entre le propylene adsorbe, un emplacement libre et l'oxygene dans la phase gazeuse. On a propose l'equation suivante de vitesse de genre Hougen-Watson
On a exprime les constantes, dans l'equation de vitesse, en fonction de la temperature.
8 citations
TL;DR: One per cent reflection and 85% transmission coefficients have been measured for wax bean leaves (Phaseolus vulgaris) at 915 MHz as discussed by the authors, and microwave radiation of intensity 15 mW/cm2 at 2450 MHz raised the leaf temperature to 25°C from an environmental cold chamber temperature of ∓5°C.
Abstract: One per cent reflection and 85% transmission coefficients have been measured for wax bean leaves (Phaseolus vulgaris) at 915 MHz. Microwave radiation has been successfully used to protect wax bean plants from freezing temperatures over extended periods of time.Microwave radiation of intensity 15 mW/cm2 at 2450 MHz raised the leaf temperature to 25°C from an environmental cold chamber temperature of ∓5°C. The plants remained healthy and fresh after removal to normal room temperatures.We expect that a microwave radiation intensity of a few milliwatts per square centimeter will suffice to protect most vegetation against normal frost. The single largest economic factor to overcome is the capital cost as the percentage operating time is expected to be small. However, the economic aspects are improved if one considers a model farm where microwave energy is also used for drying and curing.
7 citations
TL;DR: In this paper, the authors report the results of a study that aims to identify the factors that inflence university classroom verbal participation and investigates the relations between these factors by means of a questionnaire administered to 538 students in a French-speaking university of Canada.
Abstract: L’article rapporte les resultats d’une etude qui vise a identifi er les facteurs d’infl uence de la participation verbale des etudiantes et etudiants en classe universitaire et a documenter les relations entre ces facteurs. Les donnees ont ete recueillies a l’aide d’un questionnaire auto-rapporte administre aupres de 538 etudiants (64% de femmes et 36% d’hommes) d’une universite francophone du Canada. Des analyses de variance ont ete effectuees dans le but d’identifi er les eventuels effets directs et d’interaction associes aux facteurs retenus. Les resultats montrent que les hommes et les etudiants plus âges rapportent participer verbalement davantage que les femmes et les etudiants plus jeunes. De plus, les etudiants qui poursuivent des buts intrinseques plus eleves rapportent participer davantage que les etudiants qui poursuivent des buts intrinseques plus faibles. Cependant, quelques resultats contrastants ont ete observes au niveau des variables en lien avec l’enseignante ou l’enseignant. Enfi n, des effets moderateurs ont ete identifi es, notamment pour des variables motivationnelles. The article reports the results of a study that aims to identify the factors that infl uence university classroom verbal participation and investigates the relations between these factors. The data were collected by means of a questionnaire administered to 538 students (64% female and 36% male) in a French-speaking university of Canada. Analyses of variance were used to identify the possible direct and interaction effects between factors. The results show that male students and nontraditional age students indicate that they are engaged in more verbal participation than female students and traditional age students. Furthermore, students with higher intrinsic goals report that they participate more than students with weaker intrinsic goals. However, some contrasting results were observed with the instructor related variables. Finally, moderating effects were identifi ed, notably for some motivational variables.
3 citations
TL;DR: In this article, an automatic field perturbation technique to measure the electric field strength distribution in resonant structures is presented, where both component electric fields and total electric fields are measured by a suitable choice of the perturbing element.
Abstract: An automatic field perturbation technique to measure the electric field strength distribution in resonant structures is presented. The resonant structure may be a multi-mode cavity or a periodic transmission line suitably terminated for resonance perturbation tests.Both component electric fields and total electric fields may be measured by a suitable choice of the perturbing element.Several results of automatic field plots are presented.
2 citations
Journal Article•
2 citations