<p dir="ltr">Magnetorheological elastomers (MREs) are a type of smart material composed of ferrous particles suspended in a solid elastic matrix [5, 6]. When an external magnetic field is applied to an MRE, the ferrous particles tend to align with the field, causing either deformation and/or a change in the mechanical properties of the system. MREs are utilized in applications such as soft robotics, actuators, sensors, vibration control systems, and mechanical metamaterials[20, 19, 27, 5, 6, 13]. Recent demand for theses technologies has motivated an increasing focus on the material properties of MRE’s over the last 20 years [6]. Multiple authors have proposed a variety of hyperelastic mechanical and magnetomechanical models to describe these materials [16, 12, 15, 25, 14, 38, 2, 6, 8, 24]. The research presented in this dissertation focuses on the modeling and characterization of MRE’s using a systematic development of the conservation and balance laws, Maxwell’s equations, and constitutive equations needed to describe the MRE as a multi-constituent system. The material parameters resulting from the derived constitutive equations are estimated using data collected from a series of compression experiments coupled with an externally applied magnetic field. The multi-constituent constitutive equations predicted the stress of the MRE in these compression experiments for a variety of ferrous particle concentrations.</p>

The instrumental misuse of prescription stimulants as "study drugs", particularly by college students, is a serious issue that needs to be further investigated. Using data from a sample of 549 University of Central Florida Orlando students, the current study tested the relationship between prescription stimulant misuse and social learning theory, as well as general strain theory. Approximately 17% of participants reported misusing prescription stimulants for academic purposes at least once in the past year. Findings show support for social learning theory; the number of friends who use prescription stimulants and the individual's attitudes about the effectiveness of the drugs are both significant variables. General strain theory was divided into two parts; the first one tests the relationship between strain and negative affect, while the second tests negative affect, strain and prescription stimulant misuse. Overall, general strain theory was not found to explain prescription stimulant misuse. Also, results showed students who binge drink or use other substances are significantly more likely to report prescription stimulant misuse. Potential implications for these findings are discussed, as well as future research directions.

Psychological research has studied the effects of college academic demands on students' wellbeing through the moderating role of coping mechanisms. This study provides further insight by focusing on coping mechanisms among graduate students from different fields, including humanities, STEM, and social sciences. Participants were recruited at the University of Central Florida (n=97). They answered an online survey assessing the prevalence of academic stressors, the use of different coping mechanisms, and strain outcomes, including somatic symptoms, insomnia, and burnout. STEM students reported higher organizational constraints and higher interpersonal conflict compare to students in other fields. Arts and humanities students reported higher use of maladaptive coping mechanisms. The results provide an essential overview of stress patterns among graduate students, an understudy population on academic well-being.

Global crises are associated with significant shifts in the relationship functioning of romantic couples. The novel Coronavirus pandemic has caused financial distress which may pose a threat to the wellbeing of romantic couples. Previous studies show economic declines cause damaging strain on relationship functioning, specifically the relationship satisfaction, conflict resolution, and commitment influencing variables. To study the effects of the pandemic on these relationship functioning variables, researchers recruited and divided 228 participants into two groups – individuals in relationships that began before the outbreak of the COVID pandemic (Before January 2020 – pre-COVID; N= 148), and individuals in relationships that started after the initial wave of the pandemic (After March 2020 – post-COVID; N= 80). Our results show a significant association between economic strain and conflict resolution. This finding suggests that circumstances that induce financial strain – similar to the COVID-related economic declines – may be linked to the deterioration of couples' abilities to solve conflicts. Although there were no significant differences in the relationship functioning variables of individuals in relationships that began prior to the pandemic in comparison to individuals in relationships that began while the pandemic was underway, findings suggest that future analyses may lead to significant results.

In this study, impact craters in water ice are modeled using the hydrodynamic code CTH. In order to capture impact craters in ice an equation of state and a material model are created and validated. The validation of the material model required simulating the Split Pressure Hopkinson Bar (SPHB) experimental apparatus. The SPHB simulation was first compared to experiments completed on Al 6061-T6, then the ice material model was validated. After validation, the cratering simulations modeled known experiments found in the literature. The cratering simulations captured the bulk physical aspects of the experimental craters, and the differences are described. Analysis of the crater simulations showed the damaged volume produced by the projectile was proportional to the projectile’s momentum. Also, the identification of four different stages in the crater development of ice (contact and compression, initial damage progression, crater shaping, and ejected damaged material) are described.

The interaction of osteoclasts and osteoblasts regulates bone density and the maintenance of osseointegration of implants. To investigate osteoblastic response to strain, rat osteosarcoma cells were cultured on titanium plates and subjected to one of three treatments: a neutral control (0 microstrain), tension (1000 microstrain), and compression (1000 microstrain). Treatments were applied via 4 point bending for fifteen minutes each day to a strain of 1mm/m at a sinusoidal frequency of 1Hz. Cells were measured for DNA as indicator of proliferation, alkaline phosphatase as indicator of phenotype and total protein and calcium deposition as indicators of matrix formation. Results indicated that DNA and total protein differed significantly between treatments. The alkaline phosphatase levels and calcification of matrix did not. The differences in the levels of DNA indicate different growth patterns between treatments. The total protein levels imply distinctions in matrix deposition. The alkaline phosphatase and calcium levels did not vary significantly, implying no difference in bone-specificity or calcification.

Due to traumatic brain injury (TBI), numerous studies have focused on comprehensively determining the mechanical properties of the brain. This study examined the strain rate dependence of porcine brain under compression, and the microstructural damage was quantified using a confocal microscope and graphical user interface (GUI). The selected strain rates were 0.10 s-1, 0.025 s-1, and 0.00625 s-1 while the strain levels targeted for confocal imaging were 15%, 30%, and 40%. This study also characterized the stress-state dependence at a strain rate and strain level of 0.10 s-1 and 40%, respectively, under compression, tension, and shear. Strain rate dependency data exhibited viscoelastic behavior, and the analysis parameters correlated with increasing strain rate and strain level. Stress-state dependency data demonstrated distinct nonlinear behavior, and disparities were observed in the analysis parameters between different testing modes. Finite element procedures can implement this supplementary data for devising more realistic models.

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