Hand and finger force data are used in many settings, including industrial design and indicating progress during rehabilitation. The application of appropriate work design principles, during the design of tools and workstations that involve the use of the hand and fingers, may minimize upper extremity injuries within the workplace. Determination and integration of force capabilities and requirements is an essential component of this process. Available data in the literature has focused primarily on whole-hand or multi-digit pinch exertions. The present study compiled and examined maximal forces exerted by the fingers in a variety of couplings to both enhance and supplement available data. This data was used to determine whether finger strength could be predicted from other strength measures and anthropometry. In addition, this study examined whether exerted finger forces could be estimated using surface electromyography obtained from standardized forearm locations. Such processes are of utility when designing and evaluating hand tools and human-machine interfaces involving finger intensive tasks, since the integration of finger force capabilities and task requirements are necessary to reduce the risk of injury to the upper limbs. Forces were measured using strain gauge transducers, and a modification of standard protocols was followed to obtain consistent and applicable data. Correlations within and among maximum finger forces, whole-hand grip force, and anthropometric measures were examined. Multiple regression models were developed to determine the feasibility of predicting of finger strength in various finger couplings from more accessible measures. After examining a wide variety of such mathematical models, the results suggest that finger strength can be predicted from easily obtained measures with only moderate accuracy (R²-adj: 0.45 - 0.64; standard error: 11.95N - 18.88N). Such models, however, begin to overcome the limitations of direct finger strength measurements of individuals. Surface electrodes were used to record electromyographic signals collected from three standardized electrode sites on the forearm. Multiple linear regression models were generated to predict finger force levels with the three normalized electromographic measures as predictor variables. The results suggest that standardized procedures for obtaining EMG data and simple linear models can be used to accurately predict finger forces (R²-adj: 0.77 - 0.88; standard error: 9.21N - 12.42N) during controlled maximal exertions. However, further work is needed to determine if the models can be generalized to more complex tasks. / Master of Science

To understand the physical mechanism underlying the cross-field transport of mass and energy in magnetoplasmas is a long-standing problem in fusion research. Woods (1987) has recently developed a second-order transport theory which has been used to explain a number of transport-related phenomena observed in tokamaks. Here, we apply second-order transport theory to the reverse field pinch (RFP) and a phenomenon observed in tokamaks known as 'snakes'. Expressions for the mass and energy confinement times in the RFP, τ_p and τ_e, are deduced and agreement with experimental results from HBTX is found. For typical operating conditions the times τ_p ~ 0.1ms and τ_e ~ 0.2ms are observed in HBTX. Second-order transport theory predicts τ_p ~ 0.4ms and τ_e ~ 0.4ms for this machine. Scaling laws for β_p versus η_e,β_p versus I_φ and τ_e versus I_φ are compared with measurements from HBTX and agree well with observation. Snakes are large density perturbations observed in JET after fuel pellet injection. Typical snakes in JET are remarkably stable and are found to have density decay times longer than predictions based on neoclassical theory (Stringer 1987). After their formation, snakes have even been observed to grow (Weller <i>et al.</i> 1987), which suggests the presence of an inward diffusion mechanism. There is also some evidence for a temperature depression in the snakes region. An explanation of the stability and energy balance in snakes based on second-order transport theory is proposed.

A collection of short stories and a novella exploring the limits of how much people can connect with and understand one another.