4,084 research outputs found

    A Program for the Collection, Storage, and Analysis of Baseline Environmental Data for Cook Inlet, Alaska

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    The scope of this report is to provide a general, yet comprehensive, description of the Cook Inlet System which will serve as a basis for understanding the interrelated natural and man-made factors governing its future; to present a program of field research studies for the estuarine environment that will describe the existing state of the Inlet with respect to the water quality and biota; to provide a framework whereby the program of studies can be evaluated and redirected in light of the preliminary results; and, to provide a method of storing and analyzing the data from the investigations so that it can be made available to interested parties in the most efficient manner possible.This report was prepared by the Institute of Water Resources of the University of Alaska for the Alaska Water Laboratory, Federal Water Pollution Control Administration under Contract No. 14-12-449

    A study into the validation of ATP testing devices for integrated cleanliness monitoring within healthcare settings

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    There is a problem in hospital cleaning. There is currently no scientific monitoring method that provides timely and reliable assurance that harmful bacteria have been removed by the cleaning processes. This PhD investigates the validation of commercially available testing devices intended for the rapid detection of adenosine triphosphate (ATP), which may provide a quantitative surrogate estimate of surface cleanliness based on ATP measurements. The findings indicate that ATP testing devices, despite problems with scaling and imprecision, provide immediacy in readings which enables the incorporation of ATP testing into an improved and integrated cleanliness monitoring process for applications within healthcare settings

    The investigation of valve operators\u27 torque production capabilities and optimal handwheel height, angle, and opening technique

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    This research consists of two projects concerned with handwheel-valve operations. The objectives of poject-1 were to: (1) introduce an ergonomically-modified valve-wrench and compare it to conventional valve-opening methods, in terms of efficiency (time to open valve), perceived physical exertion (Borg-scale), and muscle loading of shoulder and trunk muscles; and (2) determine whether the torque setting (15 Nm and 30 Nm) of the valve affects the preferred valve-opening method. Four methods were evaluated, including using bare hands (BH), conventional wrench-restricted (CW-R, assumes presence of obstructions), conventional wrench-unrestricted (CW-U, assumes no obstructions), and modified wrench (MW). Electromyography (EMG) activities were measured from the right and left anterior deltoids, trapezii, latissimi dorsi, and erector spinae muscles. The EMG activity of each muscle was normalized to the maximum EMG activity of the corresponding muscle’s reference contraction (RC). This study used new RC procedures for the anterior deltoids and trapezii that were associated with higher EMG amplitudes than the RC procedures found in the literature. The valve-opening method that was associated with the lowest overall EMG activities was CW-R, followed by BH, MW, and finally CW-U. According to the time recordings and Borg-ratings, the MW was the most efficient and least physically demanding method in opening the valve. The objectives of project-2 were to: (1) investigate operators’ torque production capabilities and recommend maximum torque limits for different handwheel heights (knee, elbow, shoulder, and overhead levels) and angles (0o, 45o, and 90o); and (2) determine an optimal handwheel height and angle, in terms of operators’ maximum isometric torque exertions and the EMG activities of the same shoulder and trunk muscles as in project-1. The average maximum torque exertions ranged between 51.6 Nm (at overhead 0o) and 74.9 Nm (at overhead 45o) depending on the height and angle of the handwheel. Through calculating the 5th percentile torque strength values of the female participants, this study recommends maximum torque limits ranging between 13.7 Nm and 24.1 Nm, depending on the height and angle of the handwheel. Analysis of the results indicates that the optimum height and angle of a handwheel is at shoulder level and zero degree

    The total assessment profile, volume 2

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    Appendices are presented which include discussions of interest formulas, factors in regionalization, parametric modeling of discounted benefit-sacrifice streams, engineering economic calculations, and product innovation. For Volume 1, see

    All on the same train, but heading in different directions

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    Insurance company managers are surveyed to discern their alignment with four risk attitudes predicted by Plural Rationality Theory. Each company management team is shown to contain a mix of beliefs, but not always the same mix. Since each belief is tied to a different expectation for appropriate risk management, there are inherent conflicts with a risk management culture that is tied to a single belief. The paper concludes with descriptions of hybrid risk management cultures that would have some appeal to various pairs of the four beliefs

    Visual search and VDUS

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    This wide-ranging study explored various parameters of visual search in relation to computer screen displays. Its ultimate goal was to help identify factors which could result in improvements in commercially available displays within the 'real world’. Those improvements are generally reflected in suggestions for enhancing efficiency of locatabolity of information through an acknowledgement of the visual and cognitive factors involved. The thesis commenced by introducing an ergonomics approach to the presentation of information on VDUs. Memory load and attention were discussed. In the second chapter, literature on general and theoretical aspects of visual search (with particular regard for VDUs) was reviewed. As an experimental starting point, three studies were conducted involving locating a target within arrays of varying configurations. A model concerning visual lobes was proposed. Two text-editing studies were then detailed showing superior user performances where conspicuity and the potential for peripheral vision are enhanced. Relevant eye movement data was combined with a keystroke analysis derived from an automated protocol analyser. Results of a further search task showed icons to be more quickly located within an array than textual material. Precise scan paths were then recorded and analyses suggested greater systematicity of search strategies for complex items. This led on to a relatively 'pure' search study involving materials of varying spatial frequencies. Results were discussed in terms of verbal material generally being of higher spatial frequencies and how the ease of resolution and greater cues available in peripheral vision can result in items being accessed more directly. In the final (relatively applied) study, differences in eye movement indices were found across various fonts used. One main conclusion was that eye movement monitoring was a valuable technique within the visual search/VDU research area in illuminating precise details of performance which otherwise, at best, could only be inferred

    Factors that influence visual attention and their effects on safety in driving: an eye movement tracking approach

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    Statistics show that a high percentage of road related accidents are due to factors that cause impaired driving. Since information extraction in driving is predominantly a visual task, visual distraction and its implications are therefore important safety issues. The main objective of this research is to study some of the implications of demands to human’s attention and perception and how it affects performance of tasks such as driving. Specifically, the study aims to determine the changes that occur in the visual behavior of drivers with different levels of driving experience by tracking the movement of the eye; examine the effects of different levels of task complexity on visual fixation strategies and visual stimulus recognition; investigate the effects of secondary task on attentional and visual focus and its impact on driving performance; and evaluate the implications of the use of information technology device (cellular phone) while driving on road safety. Thirty-eight students participated in the study consisting of two experiments. In the first experiment, the participants performed two driving sessions while wearing a head mounted eye tracking device. The second experiment involved driving while engaging in a cellular phone conversation. Fixation location, frequency, duration and saccadic path, were used to analyze eye movements. The study shows that differences in visual behavior of drivers exist; wherein drivers with infrequent driving per week fixated more on the dashboard area than on the front view (F(3,26) = 3.53, p\u3c0.05), in contrast to the driver with more frequent use of vehicle per week where higher fixations were recorded in the front/center view (F(3,26) = 4.26). The degree of visual distraction contributes to the deterioration of driving resulting to 55% more driving errors committed. Higher time where no fixation was detected was observed when driving with distraction (from 96% to 91% for drivers with less frequency of vehicle use and 55% to 44% for drivers with more frequent use of vehicle). The number of pre-identified errors committed increased from 64 to 81, due to the effect of visual tunneling. This research presents objective data that strengthens the argument on the detrimental effects of distraction in driving
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