The increased prevalence of childhood obesity is a major concern for society. This study aims at exploring the influence of the parents (especially parental time allocation choices) on children’s obesity-related health outcomes and examining the potential differences between the fathers’ and the mothers’ marginal effects. A household with two parents and one child is modeled. The household production theory and the collective household modeling structure are combined. The model treats the mother, the father and the child as three separate agents with individual preferences. The two parents’ interaction is modeled within the collective model framework by assuming that they will reach Pareto efficient resource allocation between them. In order to capture the dynamics between parents and the child, parents-child interaction is modeled in a two-stage Stackleberg game structure where the child is allowed to have certain decision choices of his/her own. This game structure allows us to explore the parental influence on the child’s health outcomes while allowing the child to have influencing power in the household decision-making process. Based on this theoretical model, a general triangular system with one child’s health production equation and five health inputs demand equations is derived and estimated. The empirical estimation is performed for three systems: pooled model, the younger children model (of age 9 to 11), and the older children model (of age 13 to 15). The empirical results show mother-related variables show more influence on the child’s Body Mass Index (BMI) outcomes compared to father-related variables: mothers’ BMI and mothers’ work-to-home stress spillover are positively related to their children’s BMI while mothers’ time spent with their children is negatively related to their children’s BMI. There exists a complementary relationship between mothers’ income and fathers’ food preparation time. In the older children model, mothers’ own income increases tend to decrease their time spent with their children. The main contribution of this study is that it develops a general theoretical framework to capture the dynamics in parents-child interaction. Based on this theoretical model, empirical analysis and future work can be conducted in a theoretically consistent way.

Natural gas hydrates are solid crystalline substances found in the subsurface. Since gas hydrates are stable at low temperatures and moderate pressures, gas hydrates are found either near the surface in arctic regions or in deep water marine environments where the ambient seafloor temperature is less than 10°C. This work addresses the important issue of geomechanical stability in hydrate bearing sediments during different perturbations. I analyzed extensive data collected from the literature on the types of sediments where hydrates have been found during various offshore expeditions. To better understand the hydrate bearing sediments in offshore environments, I divided these data into different sections. The data included water depths, pore water salinity, gas compositions, geothermal gradients, and sedimentary properties such as sediment type, sediment mineralogy, and sediment physical properties. I used the database to determine the types of sediments that should be evaluated in laboratory tests at the Lawrence Berkeley National Laboratory. The TOUGH+Hydrate reservoir simulator was used to simulate the gas production behavior from hydrate bearing sediments. To address some important gas production issues from gas hydrates, I first simulated the production performance from the Messsoyakha Gas Field in Siberia. The field has been described as a free gas reservoir overlain by a gas hydrate layer and underlain by an aquifer of unknown strength. From a parametric study conducted to delineate important parameters that affect gas production at the Messoyakha, I found effective gas permeability in the hydrate layer, the location of perforations and the gas hydrate saturation to be important parameters for gas production at the Messoyakha. Second, I simulated the gas production using a hydraulic fracture in hydrate bearing sediments. The simulation results showed that the hydraulic fracture gets plugged by the formation of secondary hydrates during gas production. I used the coupled fluid flow and geomechanical model "TOUGH+Hydrate- FLAC3D" to model geomechanical performance during gas production from hydrates in an offshore hydrate deposit. I modeled geomechanical failures associated with gas production using a horizontal well and a vertical well for two different types of sediments, sand and clay. The simulation results showed that the sediment and failures can be a serious issue during the gas production from weaker sediments such as clays.

Texte remanié de: Diss. Ph. D.--Faculty of chemical engineering--Åbo akademi university, 2001. / Bibliogr. p. 141-145.

Dissertation--Åbo akademi, 2005. / Bibliogr. p. 163-181.

Thesis (Ph. D.)--Lehigh University, 2000. / Includes vita. Includes bibliographical references (leaves 107-112).

Thesis (Ph. D.)--Lehigh University, 2000. / Includes vita. Includes bibliographical references (leaves 125-135).

Thesis (Ph. D.)--Lehigh University, 2000. / Includes vita. Includes bibliographical references (leaves 172-188).

Thèse de doctorat : Sciences de l'ingéniueur : automatique : Metz : 2006. / Thèse soutenue sur ensemble de travaux. Bibliogr. p. 141-143.

Reproduction de : Thèse de doctorat : Génie des procédés : Toulouse, INPT : 2004. / Titre provenant de l'écran-titre. Bibliogr. 76 réf.

Thesis (M.S.)--West Virginia University, 2001. / Title from document title page. Document formatted into pages; contains xiii, 252 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 250-251).