There is little academic research that examines whether there are differences between the ways probation officers and community members perceive the use of force on juvenile offenders. Failure to understand the differences in these perceptions negatively affected a probation department in California, which failed to address public concerns regarding the use of force in the juvenile hall, which resulted in a consent decree and a costly financial settlement. Using socialization theory as the foundation, the purpose of this study was to understand if there is a statistically significant difference between probation officers and civilians regarding their perceptions of use of force against juvenile offenders. Data were collected from a nonprobability sample of probation officers (n = 71) and community members (n = 125) in a Northern California community through an online survey that featured 5 scenarios of escalating behavior from a juvenile offender. Respondents were asked to evaluate whether the use of force was appropriate or excessive for each scenario. Data were analyzed using an independent samples t test and chi-square tests of independence. Findings indicated that, overall, there is a statistically significant difference in the perception of use of force between the 2 groups (p <. -4.04). Specifically, community members are more likely to have a lower threshold of tolerance for use of force than probation officers in 3 of the 5 scenarios in the survey. The positive social change implications of this study include recommendations to probation departments in California for enhanced collaboration and training with community members to better understand the expectations of each group related to use of force and the treatment of juvenile offenders.

This thesis adds to the knowledge base of constant-force mechanisms (CFMs). It begins by reviewing past work done in the area of CFMs and then develops new nondimensionalized parameters that are used to simplify the calculations required to design a CFM. Comparison techniques are then developed that utilize these non-dimensionalized parameters to compare mechanisms based on stiffnesses, percent constant-force, actual lengths, normal displacements, and feasible design orientations. These comparison techniques are then combined with optimization to define new mechanisms with improved performance and range of capabilities. This thesis also outlines a design process, methods to identify mechanisms that are suitable for a given design problem, and relationships and trends between variables. The thesis concludes by discussing the adaptation of CFMs for use in electrical contacts and presenting the results of a design case study which successfully developed a constant-force electrical contact (CFEC).

Polypterus senegalus, an extant member of the ray-finned fishes, can both swim in water and walk overland. Both environments impose different locomotor requirements on Polypterus fins. In an aquatic environment, forward propulsion is largely generated through oscillations of the pectoral fins working in sync with each other. On land, the pectoral fins are engaged in a contralateral gait, and are involved in lifting the body off the ground while simultaneously balancing the body. Polypterus have been shown to undergo behavioural, anatomical, and physiological changes during both short- and long-term exposure to land. Differences in force environments and locomotor behaviour between aquatic and terrestrial environments are hypothesized to be the cause of these plastic changes observed in the musculoskeletal tissues of Polypterus. Despite these observable changes, it is unclear exactly how the pectoral fins are experiencing ground reaction forces (GRF) during terrestrial locomotion. By measuring and quantifying force production during walking in Polypterus, this thesis provides a first look at the relationship between GRFs produced and experienced during walking and the pectoral fins of the amphibious fish, Polypterus. The kinematics of the pectoral fins and fore body were analyzed during terrestrial locomotion, and strategic points across both pectoral fins and body were digitized. Kinematics were compared with GRFs in the thrust (X), stabilizing (Y) and lifting (Z) planes to understand how impact forces travel through the fin tissues. Further analysis, using inverse dynamics, is required to determine how these impact forces travel through the musculature of the pectoral fins, perhaps providing potential hypotheses as to the effects of GRFs and their role in not only how terrestrial locomotion affects the behavioural, anatomical, and physiological plasticity observed in Polypterus, but also the limbs of tetrapods during the evolutionary transition from aquatic to terrestrial environments.

No description available.

In general, the stability of suspension can be studied using two methods. <i>One</i> is to directly measure the forces between two interacting surfaces in media. <i>The other</i> is to study the interfacial surface free energies of the particles in suspension. Direct surface force measurements were conducted between silica surfaces in octadecyltrimetylammonium chloride (C₁₈TACl) solutions using an Atomic Force Microscope (AFM). The results showed that the hydrophobic force existed in both air-saturated and degassed C₁₈TACl solutions. The attraction decreased with NaCl addition, and was the strongest at the point of charge neutralization (p.c.n.) of silica substrate. The force measurement results obtained in C_nTACl solutions showed that the attractions decayed exponentially and became the maximum at the p.c.n.'s. The decay lengths (<i>D</i>) increased with surfactant chain length. The measured forces were fitted to a charged-patch model of Miklavic <i>et al</i>. (1994) with rather large patch sizes. It was also found that the decay length decreased linearly with the effective concentration of the CH2/CH3 groups raised to the power of -1/2. This finding is in line with the model of Eriksson <i>et al</i>. (1989). It suggested that the long-range attractions are hydrophobic forces originating from the changes in water structure across a hydrophobic surface-solution interface. For the TiO₂/water/TiO₂ system, the Hamaker constant was found to be 4±1×10^-20 J. The force curves obtained in the TiO₂/C_nTACl system showed a repulsion-attraction-repulsion transition with increasing surfactant concentration. The long-range attraction observed between TiO₂ surfaces in C_nTACl solutions reached maximum at the p.c.n., and the decay length increased with chain length. In present work, the thin-layer wicking technique was used to determine the surface free energy (γ_s) and its components of talc samples. The results showed that the basal surfaces of talc are weakly basic while the edge surfaces are acidic. The effect of chemicals on the surface free energies of talc was systemically studied. The results showed that CMC (carboxymethyl cellulose sodium salt) and EO/PO (ethylene oxide/propylene oxide) co-polymers made talc surface hydrophilic by increasing the surface free energies, especially γ^LW and γ^-. SOPA (sodium polyacrylate) increased greatly the zeta-potentials instead of the surface free energies. / Ph. D.

LD2668 .T4 1947 H37 / Master of Science

Call number: LD2668 .T4 1963 A57 / Master of Science

Call number: LD2668 .T4 1965 D27 / Master of Science

No description available.

In most flat bimetallic strip applications, the bending is employed in the transverse direction, that is, upon the application of uniform heating to the entire strip, the initially straight strip bends transversely up from the flat plane. This study is concerned with a pre-curved bimetallic strip that upon heating up from the ambient, straightens up along the chord line tending to become flatter. The initial ambient radius of curvature of the strip is smaller, and upon heating, the radius of curvature becomes larger. By mounting the curved bimetallic strip with a rotational degree of freedom at each end, and fixing one end against displacement, a chord line displacement of the free end of the strip occurs when the strip is uniformly heated. It is this chord line case that this work investigates and characterises. This work provides a way of evaluating the net combined axial loading case whereby an external load is applied to the free end of the strip as it uniformly heated. The main application of this work is for the characterisation of a curved bimetallic blade within a thermal motor. This is a novel device for converting renewable heat energy into mechanical energy and power as part of a larger energy harvesting network. The curved bimetallic strip with minor modifications, functions as a curved bimetallic blade within the thermal motor. The application of this work has a wider impact, in that it can be used in any other temperature induced force and displacement applications. Thus as a result of this investigation, a new form of linear actuator has been created that can utilise an input heat differential, and produce an output axial force and displacement. The displacements and forces generated by the axial case can be quite large, and as a result of this work, relatively easy to calculate, when designing a thermally driven linear actuator. The thermal motor, which possesses the curved bimetallic strip at the heart of its mechanism, can also be powered by other secondary heating sources such exhaust, or waste heat, that would otherwise be lost to the surroundings.