Guan J.,General Engineer Research |
Hsiao H.,General Engineer Research |
Zwiener J.V.,General Engineer Research |
Current R.S.,General Engineer Research |
And 2 more authors.
Journal of Agricultural Safety and Health | Year: 2011
This study evaluated the effectiveness of a commercial rollover protective structure (ROPS) and size-extended ROPS in protecting a 95th percentile male operator during tractor overturns. Six rear upset tests (commercial ROPS) and ten side upset tests (commercial and size-extended ROPS) were conducted. A 95th percentile instrumented male manikin was used in all tests. Head injury criterion (HIC15), 80 g limit on resultant head acceleration, neck injury criterion (Nij), and peak axial force (extension-compression) were employed to evaluate injury potential. In all rear tests, the manikin's head impact with the ground was within the tolerance limits for head/neck injuries. Based on limited trials in the side tests, the study observed a small to moderate chance of neck injuries under the commercial and size-extended ROPS conditions; the injury risk was not statistically significant between these two test conditions. This study identified a risk of non-fatal injuries for large-size operators in side overturns, although the prevention effectiveness of commercial versus size-extended ROPS cannot be determined without further testing. These findings may have implications for future ROPS designs.
Oyewole S.A.,Pennsylvania State University |
Haight J.M.,NIOSH Pittsburgh Research Laboratory
Computers in Human Behavior | Year: 2011
Website users often experience several difficulties while trying to access or navigate a website. This is mostly due to their inability to familiarize themselves with the structures in the website or as a result of complex procedures which prevent them from reaching their goals. It is therefore, important to develop a methodology or guidance technique for assisting website users to achieve their goals. A type of expert system that provides the needed guidance necessary in order to achieve these goals was proposed in this paper. A sample website was initially designed, and the analysis of website menu structure was conducted. The rules to find the optimal path are established based on the Goals, Operators, Methods, and Selection rules (GOMS) model by considering individual preferences on input devices. Derivatives of the GOMS model such as the Cognitive Perceptual Model GOMS, Natural GOMS Language, GOMS Language and GOMS Language Evaluation and Analysis were reviewed. The Card, Moran and Newell (CMN) GOMS technique was selected as the primary inference engine of the proposed expert system. This was primarily based on the highly efficient and exemplary capability of the CMN-GOMS to predict both operator sequence and execution time. The expert system was finally constructed from the result of the acquired knowledge base and other applicable rules. © 2010 Elsevier Ltd. All rights reserved.
Patts L.,NIOSH Pittsburgh Research Laboratory |
Cauda E.,NIOSH Pittsburgh Research Laboratory
Coal Age | Year: 2011
A comparison of two field instruments, an ECOMJ2KN gas and smoke particle analyzer and an iTX multigas analyzer, with a reference laboratory analyzer when challenged with the same sample extracted from a diesel engine exhaust tailpipe, was conducted. For the purpose of the test, all analyzers were employed simultaneously to measure the carbon monoxide concentration in the tailpipe of a Mercedes-Benz 904 Tier 2 diesel engine. The diesel engine loading was controlled by a water-cooled 400 kW eddy current dynamometer. All three analyzers compared were able to measure the variation in carbon monoxide concentration at each engine operating condition. The CO concentrations measured by the ECOM analyzer and iTX multigas monitor are higher than the value measured by the NDIR analyzer for each set of tests. The discrepancy in measurement value was consistently greater for the iTX multigas monitor compared to the ECOM analyzer.
Oyler D.C.,NIOSH Pittsburgh Research Laboratory |
Mark C.,NIOSH Pittsburgh Research Laboratory |
Molinda G.M.,NIOSH Pittsburgh Research Laboratory
International Journal of Coal Geology | Year: 2010
Sonic travel time logging of exploration boreholes is routinely used in Australia to obtain estimates of coal mine roof rock strength. Because sonic velocity logs are relatively inexpensive and easy to obtain during exploration, the technique has provided Australian underground coal mines with an abundance of rock strength data for use in all aspects of ground control design. However, the technique depends upon reliable correlations between the uniaxial compressive strength (UCS) and the sonic velocity. This paper describes research recently conducted by NIOSH aimed at developing a correlation for use by the U.S. mining industry. From two coreholes in Illinois, two from Pennsylvania, and one each from Colorado, western Kentucky and southern West Virginia, sonic velocity logs were compared with UCS values derived from Point Load tests for a broad range of coal measure rock types. For the entire data set, the relationship between UCS and sonic travel time is expressed by an exponential equation relating the UCS in psi to the travel time of the P-wave in μs/ft. The coefficient of determination or R-squared for this equation is 0.72, indicating that a relatively high reliability can be achieved with this technique. The strength estimates obtained from the correlation equation may be used to help design roof support systems. The paper also addresses the steps that are necessary to ensure that high-quality sonic logs are obtained for use in estimating UCS. © 2010.