Les enjeux liés aux problématiques de développement durable encouragent de plus en plus d'industriels, dans le secteur du bâtiment, à se lancer dans une politique de réduction de la consommation énergétique de leurs procédés industriels. C'est dans ce cadre qu'est menée cette étude, où nous nous intéressons au cas particulier de la fabrication des plaques de plâtre, qui de par les qualités qu'elles présentent liées à leur caractère pratique et rapide à poser (temps pour le neuf que la rénovation), sont parmi les matériaux de construction les plus utilisés à l'heure actuelle. En effet pour leur fabrication, on récupère d'abord du gypse depuis la carrière que l'on calcine pour avoir de l'hémihydrate, que l'on mélange ensuite avec de l'eau pour en faire du gypse, que nous rencontrons dans les plaques de plâtre. Cependant, pour avoir une meilleure ouvrabilité lors de la préparation, on est obligé d'ajouter une quantité d'eau excédentaire par rapport à celle que nécessite la stoechiométrie de la réaction d'hydratation – quantité qu'il faudrait évacuer par la suite par séchage. Ainsi, la fabrication des plâtre s'avère être très énergivore ; c'est tout l'intérêt de la thèse où il s'agira de mieux comprendre la physique qui régit le séchage du plâtre de façon à réduire cette surconsommation énergétique. Pour mener cette étude, nous nous sommes d'abord intéressés au cas du séchage de milieux poreux assez simples (empilement de billes de verre, tubes capillaires), nous servir ensuite de la compréhension des mécanismes physiques qui régissent le séchage de ces dits-milieux, d'une part, et des observations locales (RMN, IRM, microtomographie), d'autre part, pour expliquer les différents mécanismes physiques qui entrent en jeu lors du séchage du plâtre. Cette démarche nous a donné la possibilité d'avoir une bonne maîtrise de la physique du séchage du plâtre, c'est-à-dire l'identification des différents leviers et paramètres qui régissent sa cinétique. Ceci nous a permis de mettre en place un modèle physique pour la prédiction de cette cinétique - modèle qui peut être utilisé pour une démarche d'optimisation énergétique de la fabrication des plaques de plâtre / Issues related to sustainability encourage more building material industries to engage policies in making processes energy consumption reduction. This study is conducted in this purpose, and is focused on the case of plasterboard. Indeed for plasterboard manufacturing, gypsum from quarry are first calcined to get hemihydrate, which is then mixed with water to make again gypsum we find in plasterboard. However, to get a good workability during the preparation process, it is necessary to add an excess amount of water relative to that required by the stoichiometry of the hydration reaction. This excess water should be evacuated thereafter drying. Thus, the manufacture of gypsum proved to be very energy intensive : that is the cornerstone of this thesis, during which we will try to understand the physics that govern the drying of plaster in order to reduce its energy consumption. To conduct this study, we are primarily interested in understanding of simple porous media drying (stack of glass beads, capillary tubes). Then based on our understanding of the physical mechanisms that govern their drying, on one hand, and on local observations (NMR, MRI, microtomography), on the other hand, we give an explanation to the different physical mechanisms of plaster drying. This allows us to establish a physical model to predict the drying kinetics of plaster - model that can be used for energy optimization approach during the manufacturing process of plasterboard. Its can also be used for the drying kinetics prediction of other building materials

<div>Digital Forestry uses digital technology and multidisciplinary expertise to measure, monitor, and manage urban and rural forests to maximize social, economic, and ecological benefits. </div><div><br></div><div>In chapter 2, we investigated the potential use of CNNs for hardwood lumber identification based on tangential plane images. In chapter 3, we developed deep bark, a lightweight tree species identification application, by using deep learning. In chapter 4, we first introduced a new dataset of images of hardwood species annotated for tree ring detection. We applied the state-of-art semantic segmentation models to the dataset. In chapter 5, we combined the observed classes and non-observed classes by distinguishing the attributes of objects and applied zero-shot learning to microscopic wood images. <br></div><div> </div><div>The results above chapters demonstrated the potential and effectiveness of machine learning in many forestry-related tasks. Those applications help both the research community and industry to conduct better digital forestry business. However, we still need to point out that the availability, quality, and quantity of data and annotation are critical factors in conducting meaningful research and applications in forestry.</div>

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An experimental apparatus and test procedure to measure the sorption isotherm of moisture in porous building materials was developed and tested for its reliability and accuracy. The apparatus shows excellent potential for determining reliable moisture storage property data. The data are used in heat and moisture transport models. The apparatus consists of a small test chamber, with an external forced-air temperature and humidity conditioning system. The conditioning system supplies moist air to the test chamber at 20°C dry-bulb temperature over a range of 0.4 to 85 per cent relative humidity. The new system circumvents problems associated with the use of saturated salt-in-water solutions. Moisture content is determined gravimetrically without removing specimens from their conditioned environment. The mass is monitored in situ such that external ambient conditions have no effect on the data. The control of test chamber relative humidity and dry-bulb temperature is automated. Test results consisting of sorption isotherms and scanning curves for sugar pine, southern pine, and an exterior grade plywood are presented. The maximum uncertainty in moisture content measurement is 0.023 kg/kg-dry mass at 85 per cent RH. Results are compared to data from the literature. The study shows a need for a standard test method for measuring sorption isotherms. Minimum recommendations for such a standard test method are included. A comparison of scanning data to an analytical model from the literature show that further investigation of scanning is needed. The present method is well suited for such a study. / Master of Science

The effects of maximum size coarse aggregate on the relationship between accelerated strength and 14-day normally cured strength of normal and superplasticized concrete have been investigated. The results obtained show that differences among maximum size coarse aggregates are greater in normal concrete than in superplasticized concrete in strength-producing properties. Among the various sizes of aggregates investigated, one-half inch maximum size of coarse aggregate exhibited higher strength producing properties. This report includes the test results as well as the procedures for the preparation and testing of concrete specimens. These specimens were prepared and tested at the concrete laboratory at Virginia Polytechnic Institute and State University. / Master of Science / incomplete_metadata

In recent years there has been considerable development along the lines or using coal powdered to a fineness resembling talcum powder for the production of power in practically all the new and larger power plants. This pulverized coal burns similarly to gas when blown into the combustion chamber. Because or the fineness of the individual particles of coal, a very fine ash termed "fly ash" is formed when combustion occurs, a large portion of which is carried on up and out the smoke stack. The "fly ash," if allowed to go up the stack and out over the surrounding territory, becomes a health hazard as well as a nuisance to the cleanliness of the community. The average fly ash is about fifty per cent silica (SiO₂) which should classify it as a silicosis hazard. To avoid this nuisance and hazard, the fly ash may be collected in one of several ways, the most important being by electrostatic precipitation, wet scrubbing, and with cyclone separators. It must then either be used or disposed of. Several attempts have been made to use fly ash for some useful purpose, but it is not adaptable for filling in, for road construction, or for similar uses made of clinker ash. In this investigation, an attempt has been made to determine the optimum conditions of both the process and composition which should be used in the manufacture or a building material from fly ash, and special reference will be made to the ash of the Virginia Polytechnic Institute Power Plant, Blacksburg, Virginia. / M.S.

M.S.

From articles found in publications of the past five to ten years, it appears that in many industries the actual image of purchasing does not coincide with its textbook image, which is that of being one of the most important functions within the company. Therefore, it is the purpose of this study to show that in Virginia manufacturing firms, the actual image of purchasing is different from the one presented in textbooks. Several hypotheses are developed and tested in this study. The general hypothesis states that the image of purchasing in Virginia manufacturing firms does not coincide with its textbook image of being one of the most highly recognized and important management functions, equal in status with sales and production. Many books, articles, related studies, and surveys were reviewed for pertinent data. In addition, two questionnaires were developed. One was used to survey VPl students in the fields of Business Administration and Engineering to acquire information about their knowledge and opinions of the purchasing field. The second one was used to survey 250 manufacturing firms in the State of Virginia concerning the purchasing functions. A return of 41.6 percent was experienced, and of these, 40 companies were classified as large businesses and 62 classified as small businesses on the basis of the number of employees. In investigating the purchasing image, the data from the questionnaires were compiled and presented in the following categories: location in the organizational structure, responsibilities, salaries, recognition, position status, career advancement, sources of purchasing personnel, personal characteristics, and educational background. Data from books and articles reviews in this study were combined with the questionnaire results in order to present a more complete analysis of the purchasing image. Based on the findings of the study, the general hypothesis stated above was rejected. It was concluded that progress had been made in developing the image of purchasing in Virginia manufacturing firms, but additional efforts are required to make the actual image of purchasing coincide with the theoretical image. Most of the other hypotheses were accepted based on the findings and the lack of contradictory evidence. Several recommendations were made which should be of assistance in improving this image. These recommendations were directed toward company management for use in their role of improving the purchasing image. / Master of Science