Thin-Film Sparse Boundary Array Design for Passive Acoustic Mapping During Ultrasound Therapy

A new 2-D hydrophone array for ultrasound therapy monitoring is presented, along with a novel algorithm for passive acoustic mapping using a sparse weighted aperture. The array is constructed using existing polyvinylidene fluoride (PVDF) ultrasound sensor technology, and is utilized for its broadband characteristics and its high receive sensitivity. For most 2-D arrays, high-resolution imagery is desired, which requires a large aperture at the cost of a large number of elements. The proposed array's geometry is sparse, with elements only on the boundary of the rectangular aperture. The missing information from the interior is filled in using linear imaging techniques. After receiving acoustic emissions during ultrasound therapy, this algorithm applies an apodization to the sparse aperture to limit side lobes and then reconstructs acoustic activity with high spatiotemporal resolution. Experiments show verification of the theoretical point spread function, and cavitation maps in agar phantoms correspond closely to predicted areas, showing the validity of the array and methodology.

Design Simulation for Solar Energy Research and Education

Solar research is primarily conducted in regions with consistent sunlight, severely limiting research opportunities in many areas. Unfortunately, the unreliable weather in Lewisburg, PA, can prove difficult for such testing to be conducted. As such, a solar simulator was developed for educational purposes for the Mechanical Engineering department at Bucknell University. The objective of this work was to first develop a geometric model to evaluate a one sun solar simulator. This was intended to provide a simplified model that could be used without the necessity of expensive software. This model was originally intended to be validated experimentally, but instead was done using a proven ray tracing program, TracePro. Analyses with the geometrical model and TracePro demonstrated the influence the geometrical properties had results, specifically the reflector (aperture) diameter and the rim angle. Subsequently, the two were approaches were consistent with one another for aperture diameters 0.5 m and larger, and for rim angles larger than 45°. The constructed prototype, that is currently untested, was designed from information provided by the geometric model, includes a metal halide lamp with a 9.5 mm arc diameter and parabolic reflector with an aperture diameter of 0.631 meters. The maximum angular divergence from the geometrical model was predicted to be 30 mRadians. The average angular divergence in TraceProof the system was 19.5 mRadians, compared to the sun’s divergence of 9.2 mRadians. Flux mapping in TracePro showed an intensity of 1000 W/m2 over the target plane located 40 meters from the lamp. The error between spectrum of the metal halide lamp and the solar spectrum was 10.9%, which was found by comparing their respective Plank radiation distributions. The project did not satisfy the original goal of matching the angular divergence of sunlight, although the system could still to be used for optical testing. The geometric model indicated performance in this area could be improved by increasing the diameter of the reflector, as well as decreasing the source diameter. Although ray tracing software provides more information to analyze the simulator system, the geometrical model is adequate to provide enough information to design a system.

Distress Disclosure and Personality in College Students

This study examined distress disclosure, the tendency to confide unpleasant feelings and experiences to others. Other factors under consideration were gender, personality factors (such as extraversion and one's general tendency to disclose), and the identity of the person to whom individuals were asked to disclose. The subject pool included 22 male and 34 female volunteers from Bucknell University. Participants were asked to complete a measure of basic demographics, the Distress Disclosure Index, and the NEO-FFI measure of personality. They were then asked to disclose about an aspect of their lives that they personally found stressful, as if they were confiding in a best friend, a parent, or a professor, respectively. The transcriptions of those recordings were coded for length, depth, and breadth of the disclosure. The researcher hypothesized that greater length, depth, and breadth would be disclosed by females who scored highly on the Distress Disclosure Index, had high extraversion scores on the NEO-FFI, and had been asked to disclose to a best friend. The study found positive associations between openness and depth, neuroticism and depth, and gender with length, such that males were more likely to have longer disclosures. Negative associations were found between extraversion and depth, neuroticism and length, and openness and breadth. Personality factors, gender, and the disclosure target may act as better predictors of the tendency to disclose, rather than of the particular dimensions of disclosure, since every instance is unique.

The Psychosocial Quality of Nursing Home Work

Trained observers used components of the functional job analysis technique to categorize 3,371 tasks performed by 214 nursing assistants in four nursing homes on five occasions over 12 months. The extent to which each task was oriented toward residents versus data or things was coded along with the "level of complexity" of each of these orientations. A psychosocial index was created by multiplying orientation by complexity. Three questions structured the analyses: (a) To what extent do nursing assistants' tasks involve interacting with residents, as opposed to focusing on data or manipulating things? (b) How complex are these tasks? (c) What are the implications of the task analysis data for assessing the quality of psychosocial care? Findings reveal that even among the direct care tasks (69% of total), the orientation was not predominantly toward the resident. Functional complexity of the tasks observed was consistently low. Those task types with the greatest psychosocial quality were those performed least frequently and vice versa. Implications of these results for restructuring nursing assistants' work are discussed.