Emergency stop controls are essential parts of industrial machinery because they are designed to stop the operation in case of emergencies without risks to operators, equipment, products, or facilities. Current guidelines for emergency stop controls have been formulated based on experience but not on empirical studies. The main objectives of this research were to determine the effects of the type and orientation of emergency stop pushbuttons on the reaction time, mode of activation, and preferences of subjects in order to formulate guidelines for their selection. An experiment consisting of a simple, cooperative assembly operation with a Microbot was designed for this study. The main conclusions of this research are that reaction time to activate emergency stop pushbutton is not affected by the orientation of the control but it is influenced by the type of control. The mode of activation of emergency stop pushbuttons is influenced by both the type and the orientation of the control. Subjects preferred emergency stop pushbuttons without guards or with half guards over controls with full guards, and subjects also preferred an inclined orientation of the control over horizontal or vertical orientations. The following guidelines are recommended for the selection of emergency stop pushbuttons. Select emergency stop pushbuttons without guards. If a guard is absolutely required, select a guard with slots or a half guard to ensure adequate visibility of and access to the button. If possible, give emergency stop pushbuttons an inclined orientation (about 45��) on the control panel. Avoid using vertical orientations for these controls. / Graduation date: 1997

INTRODUCTION: Older people are a vulnerable population for falls and the risk may be increased by unfamiliar hospital environments. Using a mixed method ergonomic approach to acknowledge the complexity of contemporary hospital environments, this thesis aims to explore the associations between patient characteristics and environmental causal factors of in-patient falls for older people. METHODS: A series of three exploratory pilot studies were carried out, followed by two large scale research projects using nationally collected data from patient incident reports and overnight bedrail audits. The mixed method approach included; secondary data analysis, interviews, surveys, and audits. MAIN FINDINGS: 1. Patients in care of older people wards have different characteristics compared to same age peers in other wards, with higher levels of frailty and confusion. 2. Bedrail use was found to rise with increasing level of confusion which is against general guidance. Staff rationales for bedrail use suggested an underlying intent to restrain confused patients. 3. Up to 92% of patients falls were reported to be un-witnessed. This may be explained by only 24% of patient beds being visible from nursing stations. 4. There were significant differences found in the fall locations between patients who were described as frail and those who were described as confused. CONCLUSION: Patients in care of older people wards have a different set of characteristics compared to same age peers in other wards. This suggests that they will have different requirements for fall prevention in terms of layout, visibility, equipment use and facilitating independence. Further research should focus on designing wards for care of older people patients which improve visibility, layout and way-finding to toilets and investigate whether these design improvements will facilitate independent movement and prevent patient falls.

Virginia's Smart Road, to be completed by early 2000, is a test bed for numerous research activities including snow and ice control, remote sensor testing, snow removal management, safety and human factors, and vehicle dynamics. An all-weather testing system will feature 75 automated snowmaking towers. In order to provide timely and repeatable weather scenarios, equipment operators will need to understand fully the limitations and capabilities of the snowmaking system. The research presented herein addresses the hydraulic and hydrologic variables and design methodology to implement efficient snowmaking at a transportation research facility. Design variables include nozzle configuration, water pressure and flowrate, compressed air pressure and flowrate, tower orientation, snow inducer concentration, water and compressed air temperature, and ambient weather conditions. Testing and data collection was performed at the Snow Economics, Inc. research and development site at Seven Springs Mountain Resort in Champion, PA. The results of this work will be used to guide the operators of the Smart Road on the most efficient use of the snowmaking equipment. / Master of Science