This study sought to evaluate the effect of participation in the Student-Guided Supports (SGS) curriculum on student behavior. The SGS curriculum was designed to teach students a set of simple behaviors to prompt and reinforce supportive teacher behavior. Student use of the SGS behaviors was hypothesized to initiate a constructive cycle of student-teacher interactions that increase teacher display of supportive behaviors and student display of SGS behaviors and academic engagement. Results of the study provided evidence of a functional relation between participation in the SGS curriculum and increased student use of requests for teacher feedback. They also provided evidence of a functional relation between student requests for feedback and teacher provision of feedback. While this study did not provide evidence of the establishment of constructive cycles of support it did offer the following: a) high school teachers typically engaged in low levels of the identified support behaviors, and b) students were able to reliably elicit these supportive behaviors by engaging in relatively simple prompting behaviors. Potential implications of the results and future research are discussed.

This thesis aims to explain how the involvement of secondary parties affect the duration of intrastate armedconflicts. It argues that the acquisition of secondary support in favor of rebel groups is likely to lead to an extended duration of intrastate armed conflict. By granting a relatively weaker rebel group secondary support, a secondary party ought to directly alter the balance of power and capabilities in benefit for the rebels. The secondary party could thereby be able to level the balance of capabilities between a government and a rebel group, creating a situation in which the, at first, stronger government now have to face a rebel group capable of surviving longer. Using a structured focused comparison on two cases, the results find secondary support in the form of funding or economic support given to relatively weak rebels to be an important influence on extending the duration of intrastate armed conflicts. Nonetheless, further research might have to be made in order to fully understand the even more detailed mechanisms behind the strong influences of economic secondary support on conflict duration.

A model was developed to facilitate secondary tailgate support selection based on analysis of a data base of over 100 case studies compiled from two different surveys of operating longwall coal mines in the United States. The ALPS (Analysis of Long wall Pillar Stability) program was used to determine adequacy of pillar design for the successful longwall case histories. A relationship was developed between the secondary support density necessary to maintain a stable tailgate entry during mining and the CMRR (Coal Mine Roof Rating). This relationship defines the lower bound of secondary support density currently used in longwall mines. The model used only successful tailgate case history data with adequate ALPS SF according to the CMRR for each case. This model facilitates mine design by predicting secondary support density required for a tailgate entry depending on the ALPS SF and CMRR, which can result in significant economic benefits. / Master of Science

AN ABSTRACT OF THE THESIS OF Behrooz Abbasi, for the Master of Science Degree in Mining and Mineral Resources Engineering, at Southern Illinois University Carbondale TITLE: A NUMERICAL ANALYSIS OF MINE INTERSECTIONS AND SUPPORT SYSTEMS FOR STABILITY MAJOR PROFESSOR: Dr. Yoginder P. Chugh Back ground: Partial extraction room-and-pillar mining systems provide about 60 % of the underground coal mined in the USA. This mining system develops 3-way and 4-way intersections. Rock falls related to fatal and nonfatal injuries in the USA for the period 2002 to 2007 identified that about 70% of these falls occur at intersections even though they represent only about 20-25 % of the area mined. A recent study on 2004 to 2008 roof-falls data base (RFDB) for Illinois mines, found that over 80% of these falls occurred at intersections. Thus, there is a significant need to improve stability of coal mine intersections if fatal and nonfatal injuries are to be controlled. The overall goal of this research is to develop an improved scientific understanding of stress distribution and instability around a 4-way intersection. An additional goal is to evaluate primary and secondary support layouts for improved stability around 4-way intersections. The following specific tasks were established for this research. * Perform 3-D numerical analyses to develop a better understanding of stress, strain and displacement distributions and associated instabilities around a 4-way intersection to identify ground support requirements. * Identify primary and secondary supports systems that may be suited to meet ground support requirements in (1) above. * Perform numerical analyses with identified primary and secondary supports installed to assess improvements in stability around an intersection. Analyses results show that pillar ribs across an intersection fail first and lead to progressive failure of immediate roof layers. The failure of immediate roof layers extends about 1.8m. In detail, coal ribs around the intersection corners mostly fail due to tensile stress, while roof and floor strata fail due to shear stresses and rib center fail due to combination of shear and tension mechanism. Primary supports significantly improve stability, but they are not adequate to ensure stability of four-way intersections. Secondary supports are needed to further improve stability of intersections. Also, based on the failure analysis a new secondary support system plan was proposed and analyzed.