Finite Element Modeling of Geosynthetic Soil Reinforcement Over Shallow Buried Pipes

Buried pipes serve an important role in many engineering applications and are vital to the infrastructure of our everyday life. It is imperative that, once in place, these pipes last as long as possible to avoid failure and costly replacement. Advancements in technology and understanding of soil-pipe interactions can extend the service life of these pipes. In this study, a new approach is taken to increase buried pipe performance.;The purpose of this research work is to explore the potential improvements of pipe performance under surface loading by using a geosynthetic reinforcement in the soil layer above a buried pipe. Various aspects of soil-pipe interactions and geosynthetic-soil interactions are considered to develop a plausible scenario where geosynthetic reinforcement can be a benefit. An extensive series of numerical investigations were conducted to analyze various aspects of this buried pipe system by using the Finite Element Method. The influence of geotextile width, geotextile stiffness, pipe depth, pipe size, trench soil stiffness, and frictional interactions on the pipe performance is investigated.;Results from this study show that at shallow pipe depths a layer of geotextile soil reinforcement can reduce pipe deflections by up to 36% when the trench soil above the pipe is weak. The improvement decreases significantly when pipe depth is increased or when the soil over the pipe is stiff. Further research work including an economic analysis may prove that the ideas put forth in this study have relevance in other field applications

Radiator design system computer programs

Minimum weight space radiator subsystems which can operate over heat load ranges wider than the capabilities of current subsystems are investigated according to projected trends of future long duration space vehicles. Special consideration is given to maximum heat rejection requirements of the low temperature radiators needed for environmental control systems. The set of radiator design programs that have resulted from this investigation are presented in order to provide the analyst with a capability to generate optimum weight radiator panels or sets of panels from practical design considerations, including transient performance. Modifications are also provided for existing programs to improve capability and user convenience

An Exploration of the Relationship between Academic Emotions and Goal Orientations in College Students before and after Academic Outcomes

In this dissertation, the intersection between emotion and motivation was explored. Participants in this study were given a survey at two time points during the semester. Using this data, the factor structure for the motivation construct as described by Elliot and colleagues were explored using a MTMM model. Leading from the measurement model from the CFA, results indicated that emotion and motivation are highly related, but in different ways depending on if the students have had academic feedback. The academic feedback also may change some students’ motivational orientations, based on their emotional reaction