Modeling of shape memory alloys with plasticity

Shape memory alloys are a special class of metals that can undergo large deformation yet still be able to recover their original shape through the mechanism of phase transformations. However, when they experience plastic slip, their ability to recover their original shape is reduced. This is due to the presence of dislocations generated by plastic flow that interfere with shape recovery through the shape memory effect and the superelastic effect. A one-dimensional model that captures the coupling between shape memory effect, the superelastic effect and plastic deformation is introduced. The shape memory alloy is assumed to have only 3 phases: austenite, positive variant martensite and negative variant martensite. If the SMA flows plastically, each phase will exhibit a dislocation field that permanently prevents a portion of it from being transformed back to other phases. Hence, less of the phase is available for subsequent phase transformations. A constitutive model was developed to depict this phenomena and simulate the effect of plasticity on both the shape memory effect and the superelastic effect in shape memory alloys. In addition, experimental tests were conducted to characterize the phenomenon in shape memory wire and superelastic wire. ^ The constitutive model was then implemented in within a finite element context as UMAT (User MATerial Subroutine) for the commercial finite element package ABAQUS. The model is phenomenological in nature and is based on the construction of stress-temperature phase diagram. ^ The model has been shown to be capable of capturing the qualitative and quantitative aspects of the coupling between plasticity and the shape memory effect and plasticity and the super elastic effect within acceptable limits. As a verification case a simple truss structure was built and tested and then simulated using the FEA constitutive model. The results where found to be close the experimental data. ^

Effects of special educator peer coaching on general educator effectiveness in inclusive classroom settings

This dissertation investigated the effects of a peer coaching relationship between a special education teacher and two general education teachers. More specifically, a two-tier multiple baseline design across subjects was used to evaluate the effects of peer coaching on the general education teachers' use of effective instructional practices (EIPs) and subsequent effects on the engagement rate and academic performance of students with and without disabilities. The peer coaching process included modeling, direct support, and feedback on the use of effective instructional practices including getting student attention, giving specific directions, asking specific questions with wait time, contingent positive reinforcement, positive error correction, precorrection, prompting, and proximity control. A 30-second partial interval recording procedure was used to observe the general education teachers' use of effective instructional practices and student engagement rates. Student participants' academic performance was measured using weekly quizzes. ^ Peer coaching resulted in an overall increase in the teachers' use of EIPs. One general education teacher had a 30% increase in average EIP use from 46% during the baseline phase to 76% during intervention. Student engagement for her two student participants with and without disabilities indicated an increase from 54% to 69% and from 47% to 65% respectively. Results for the second general education teacher indicated a 34% increase in average EIP use from 55% during the baseline to 89% during intervention. Student engagement for the two student participants with and without disabilities in her class increased from 48% to 83% and from 29% to 71% respectively. Student academic performance showed a small increase. In follow-up observations, the effects of peer coaching on teacher use of EIPs and student engagement and academic performance were maintained. ^ The results of this study suggest that using peer coaching to support general education teachers can be an effective method to improve the educational outcomes of students with and without disabilities in general education. Further research is needed to investigate the effects of peer coaching with other special and general educator partnerships and other student participants. ^

Class placement and academic and behavioral variables as predictors of graduation for students with disabilities

Dropout rates impacting students with high-incidence disabilities in American schools remain staggering (Bost, 2006; Hehir, 2005). Of this group, students with Emotional Behavioral Disorders (EBD) are at greatest risk. Despite the mandated national propagation of inclusion, students with EBD remain the least included and the least successful when included (Bost). Accordingly, this study investigated the potential significance of inclusive settings and other school-related variables within the context of promoting the graduation potential of students with Specific Learning Disabilities (SLD) or EBD. This mixed-methods study investigated specified school-related variables as likely dropout predictors, as well as the existence of first-order interactions among some of the variables. In addition, it portrayed the perspectives of students with SLD or EBD on the school-related variables that promote graduation. Accordingly, the sample was limited to students with SLD or EBD who had graduated or were close to graduation. For the quantitative component the numerical data were analyzed using linear and logistic regressions. For the qualitative component guided student interviews were conducted. Both strands were subsequently analyzed using Ridenour and Newman’s (2008) model where the quantitative hypotheses are tested and are later built-upon by the related qualitative meta-themes. Results indicated that a successful academic history, or obtaining passing grades was the only significant predictor of graduation potential when statistically controlling all the other variables. While at a marginal significance, results also yielded that students with SLD or EBD in inclusive settings experienced better academic results and behavioral outcomes than those in self-contained settings. Specifically, students with SLD or EBD in inclusive settings were found to be more likely to obtain passing grades and less likely to be suspended from school. Generally, the meta-themes yielded during the student interviews corroborated these findings as well as provided extensive insights on how students with disabilities view school within the context of promoting graduation. Based on the results yielded, provided the necessary academic accommodations and adaptations are in place, along with an effective behavioral program, inclusive settings can be utilized as drop-out prevention tools in special education.

Class in Classrooms: The Challenges Public Librarians Face as Border Crossing Educators

In border crossing pedagogy, educators help students negotiate identity and cultural issues. Public librarians help special populations of patrons improve on class issues through education. This study explored the issues public librarians face when they teach and border cross across social classes.

Class Placement and Academic and Behavioral Variables as Predictors of Graduation for Students with Disabilities

Dropout rates impacting students with high-incidence disabilities in American schools remain staggering (Bost, 2006; Hehir, 2005). Of this group, students with Emotional Behavioral Disorders (EBD) are at greatest risk. Despite the mandated national propagation of inclusion, students with EBD remain the least included and the least successful when included (Bost). Accordingly, this study investigated the potential significance of inclusive settings and other school-related variables within the context of promoting the graduation potential of students with Specific Learning Disabilities (SLD) or EBD. This mixed-methods study investigated specified school-related variables as likely dropout predictors, as well as the existence of first-order interactions among some of the variables. In addition, it portrayed the perspectives of students with SLD or EBD on the school-related variables that promote graduation. Accordingly, the sample was limited to students with SLD or EBD who had graduated or were close to graduation. For the quantitative component the numerical data were analyzed using linear and logistic regressions. For the qualitative component guided student interviews were conducted. Both strands were subsequently analyzed using Ridenour and Newman’s (2008) model where the quantitative hypotheses are tested and are later built-upon by the related qualitative meta-themes. Results indicated that a successful academic history, or obtaining passing grades was the only significant predictor of graduation potential when statistically controlling all the other variables. While at a marginal significance, results also yielded that students with SLD or EBD in inclusive settings experienced better academic results and behavioral outcomes than those in self-contained settings. Specifically, students with SLD or EBD in inclusive settings were found to be more likely to obtain passing grades and less likely to be suspended from school. Generally, the meta-themes yielded during the student interviews corroborated these findings as well as provided extensive insights on how students with disabilities view school within the context of promoting graduation. Based on the results yielded, provided the necessary academic accommodations and adaptations are in place, along with an effective behavioral program, inclusive settings can be utilized as drop-out prevention tools in special education.