Modeling and exergy and exergoeconomic optimization of a gas turbine power plant using a genetic algorithm

ABSTRACT In this paper, the thermodynamic modelling of a gas turbine power plant in Iran is performed. Also, a computer code has been developed based on Matlab software. Moreover, both exergy and exergoeconomic analysis of this power plant have been conducted. To have a good insight into this study, the effects of key parameters such as compressor pressure ratio, gas turbine inlet temperature (TIT), compressor and turbine isentropic efficiency on the total exergy destruction, total exergy efficiency as well as total cost of exergy destruction have been performed. The modelling results have been compared with an actual running power plant located in Yazd city, Iran. The results of developed code have shown reasonable agreement between the simulation code results and experimental data obtained from power plant. The exergy analysis revealed that the combustion chamber is the must exergy destructor in comparison with other components. Also, its exergy efficiency is less than other components. This is due to the high temperature difference between working fluid and burner temperature. In addition, it was found that by the increase of TIT, the exergy destruction of this component can be reduced. On the other hand, the cost of exergy destruction is high for the combustion chamber. The effects of design parameters on exergy efficiency have shown that increase in the air compressor ratio and TIT, increases the total exergy efficiency of the cycle. Furthermore, the results have revealed that by the increase of TIT by 350 0 C, the cost of exergy destruction is decreased about 22%. Therefore, TIT is the best option to improve the cycle losses. In addition, an optimization using a genetic algorithm has been conducted to find the optimal solution of the plant

A Connected Generation? Digital Inequalities in Elementary and High School Students According to Age and Socioeconomic Level | Une génération connectée? Inégalités numériques chez les élèves du primaire et du secondaire selon l’âge et le milieu socioéconomique

The objective of this article was to better understand the relationship between students’ age and socioeconomic level, and its influence on students’ digital uses. We conducted a quantitative study of 401 elementary and high school students in Quebec. Four independent variables were initially selected: two related to age (actual age and education level) and two others related to the socioeconomic environment (school poverty index and parents’ employment status). The dependent variable that represented students’ digital uses was the number of different technologies they used weekly. We conducted correlation tests followed by a linear regression analysis. Socioeconomic level appears to have a stronger influence on students’ digital uses compared to age, and explanations for this are proposed. L'objectif de cet article est de mieux comprendre la relation entre l’âge et le milieu socioéconomique des élèves dans leurs usages numériques. Nous avons mené une étude quantitative auprès de 401 élèves du primaire et du secondaire dans la région de Montréal. Quatre variables indépendantes ont été sélectionnées initialement, dont les deux premières renvoient à l'âge (l'âge et l'ordre d'enseignement) alors que les deux dernières renseignent sur le milieu socioéconomique (l'indice de défavorisation des écoles et la situation d'emploi des parents d'élèves). La variable dépendante permettant de rendre compte des usages numériques des élèves était le nombre de technologies qu'ils utilisent sur une base hebdomadaire. Nous avons procédé à une régression linéaire précédée de tests de corrélation. Il en ressort que le niveau socioéconomique semble influencer davantage les usages numériques des élèves que l'âge pour plusieurs raisons explorées dans cette recherche

Disparités d’adoption des technologies en pédagogie universitaire : un aperçu empirique

Bien que les études traitant de l’intégration des technologies en pédagogie universitaire soient relativement nombreuses, peu d’entre elles se sont penchées sur les disparités d’adoption des technologies parmi les enseignants universitaires. Aussi, l’objectif de cet article est de caractériser les profils d’enseignants universitaires adoptant les technologies. Un questionnaire a été rempli par 391 enseignants de deux universités du Québec. Des analyses par clusters permettent d’identifier trois profils d’enseignants universitaires intégrant les technologies relativement à trois volets de leur enseignement : préparation et gestion, pilotage, et développement professionnel. Les résultats laissent penser que les disparités d’adoption ne se sont pas résorbées malgré la succession de plus en plus rapide des technologies en pédagogie universitaire

Les travailleurs migrants temporaires au Québec : des migrants connectés ?

Les études sur les usages des technologies de l’information et de la communication (TIC) par les migrants ont fait l’objet d’un intérêt scientifique croissant ces dernières années. En revanche, peu d’études se sont penchées sur le cas particulier des travailleurs migrants temporaires, qui vivent annuellement des phases de non-migration et des phases de migration. Aussi, l’objectif de cette étude est de mieux comprendre l’accès et les usages des TIC par cette catégorie de migrants au Québec. Les résultats obtenus au moyen d’une enquête auprès de 24 travailleurs agricoles mexicains et guatémaltèques indiquent que le fait de migrer correspond à une réduction de la diversité des usages des TIC pour une majorité des participants. Toutefois, une minorité d’entre eux semblent utiliser au Québec une ou des TIC (le téléphone cellulaire principalement) qu’ils n’utilisaient pas dans leur société d’origine. En outre, l’éducation et la nationalité ressortent comme deux variables associées aux variations d’usage des TIC au sein de cet échantillon. Des pistes d’explication de ces résultats sont explorées en référence à la littérature scientifique du domaine des TIC et de la migration.Information and communications technology (ICT) use by migrants is a growing research field. However, so far, few studies have focused on temporary migrants workers, who experience periods of migration and periods of non-migration on a yearly basis. The objective of this paper is to gain a better understanding of ICT use by 24 Mexican and Guatemalan agricultural temporary migrant workers in Quebec. The results show that migration tends to reduce the diversity of ICT use for most of the participants. However, a few of them seem to use one or more ICT (mainly the cell phone) in Quebec that they did not use in the source society. Moreover, education and citizenship are two variables that are linked to ICT use in this sample. These results are discussed in regards to the scientific literature on ICT and migration.Los estudios sobre el uso de las tecnologías de información y comunicación (TIC) para migrantes han sido objeto de un creciente interés científico en los últimos años. En cambio, pocos estudios se han realizado en el caso específico de los trabajadores migrantes temporales, que viven cada año periodos intermitentes de migración a nuevos entornos físicos y culturales. El presente estudio tiene como propósito mejorar la comprensión del acceso y uso de las TIC por parte de esta categoría de migrantes en Quebec. Los resultados obtenidos por medio de un cuestionario a 24 trabajadores agrícolas mexicanos y guatemaltecos indican que el hecho de migrar equivale a una reducción en la diversidad de usos de las TIC para la mayoría de los participantes. Sin embargo, una minoría de ellos parece utilizar una TIC principalmente, el teléfono celular, que no utilizan en su lugar de origen. Entre otros resultados obtenidos, dos variables resaltan en el uso de las TIC, el nivel de educación y nacionalidad de los encuestados. En el presente estudio, exploramos varias hipótesis para explicar estos resultados con referencia a la literatura científica publicada sobre las TIC y la migración

(ENT 300) Fundamentals of Entrepreneurship Four'es-Ta & Juice (Pasta & Juice) / Claudia Roland Sading... [et al.]

Pasta or spaghetti is known as an expensive food and hard to make Some people prefer to eat instant noodles which are convenient, easier to make and cheaper but not healthy. Thus, we want to change their mindset and promote pasta or spaghetti as a healthy food at an affordable price to feed their family and themselves. We also expected that it have a bright future in expansion and growth of business

Oxford-MEST classification in IgA nephropathy patients: A report from Iran.

BACKGROUND There is a limited knowledge about the morphological features of IgA nephropathy (IgAN)in the middle east region. OBJECTIVES The objective of this study was to evaluate the spectrum of histopathological findings in IgAN patients at our laboratory. PATIENTS AND METHODS At this work, an observational study reported which was conducted on IgAN patients using the Oxford-MEST classification system. RESULTS In this survey, of 102 patients 71.6 % were male. The mean age of the patients was 37.7 ± 13.6 years. Morphologic variables of MEST classification was as follows; M1: 90.2 %, E: 32 %, S: 67 % also,T in grads I and II were in 30% and 19% respectively, while 51% were in grade zero. A significant difference was observed in segmental glomerulosclerosis (P=0.003) and interstitial fibrosis/tubular atrophy frequency distribution (P= 0.045), between males and females . Furthermore, it was found that mesangial hypercellularity was more prevalent in yonger patients. Moreover, there was a significant correlation between serum creatinine and crescents (P<0.001). There was also significant correlation of serum creatinine with segmental glomerulosclerosis (P<0.001). CONCLUSIONS Higher prevalence of segmental glomerulosclerosis and interstitial fibrosis/ tubular atrophy, as the two of, four variables of Oxford-MEST classification of IgAN in male patients further attests that male gender is a risk factor in this disease.In this study the significant correlation between serum creatinine and crescent was in an agreement with previous studies and suggests for the probable accomodation of extracapillary proliferation as a new variable in MEST system

Effect of virtual mass force on prediction of pressure changes in condensing tubes

Three-fluid model is used to calculate the pressure drops in a vertical pipe with the annular flow pattern for condensing steam. The three-fluid models are based on the mass, momentum, and energy balance equations for each of the fluid streams in the annular flow. There are discrepancies between predictions of three-fluid model for pressure drops and the experimental data for pressure drops when using the avail­able correlations for steam-film interfacial friction. The correlation by Stevanovic et at provides good match with experimental data, but it does not take into account some important factors affecting the pressure drops in its three-fluid model. One of these significant factors which is considered in the three fluid model used in the present paper is virtual mass (added mass) force term. Inclusion of the virtual mass force improves the pressure drop predictions such that they agree much better with the experiments