Biomedical subjects

L G Glascoe

Publications and source records attributed to L G Glascoe.

3 recordsLinked to original sources

PubMed1995

Internal cavitation in simple head impact model.

A two-dimensional computational model is used to evaluate the potential for cavitation to occur inside the brain material during head impact. The model represents a simple water-filled 14-cm-diameter, 5-cm-deep cylinder. For the purpose of our study, this cylinder represents the skull while the water inside the cylinder represents the brain material. To ensure that the stress predicted by the model is realistic, it has been calibrated against experimental data. When the cylinder is struck by a free-flying mass cavitation is initiated at the boundary opposite impact. Significant vaporous regions may develop at the boundary, while only limited vaporization occurs internally. Higher accelerations, or an additional loading of the domain by a constant acceleration perpendicular to impact, adds to the likelihood and to the severity of internal cavitation. This indicates that preexisting conditions or complex loading conditions of the head during an impact event may affect the cavitation response. Such conditions could be the result of angular velocity, angular accelerations, or head accelerations as a result of neck loading.

Brain↗

PubMed1995

Cavitation/boundary effects in a simple head impact model.

An experimental and numerical analysis of the impact response of a simple model of the human head is presented. A water-filled 14-cm diameter cylinder was struck by a 10 kg free flying mass. Rigid-body acceleration-time-history and the pressure at the fluid-cylinder interface were monitored during the impact event. Comparisons between the experimental results and the results of a computational model were made. The computational model used is a two-dimensional finite difference code simulating the physical experiment. The code incorporates a thin layer of air and the potential for vaporization along the inside of the cylinder. The study indicates that during a severe impact to the human head, the stresses generated within the brain can result in cavitation on the far side of impact followed by a sudden cavity collapse which can be quite violent. The study identifies how a skull-brain interface and cavitation can potentially affect the internal pressure response of the brain when subjected to a sudden impact.

Acceleration↗

PubMedDate not supplied

Validation of the multiscale thermohydrologic model used for analysis of a proposed repository at Yucca Mountain.

Performance assessment and design evaluation of the proposed repository at Yucca Mountain are facilitated by a thermohydrologic modeling tool that simultaneously accounts for processes occurring at a scale of a few tens of centimeters around individual waste packages and emplacement drifts, and accounts for processes at the multi-kilometer scale of the mountain. The most straightforward approach is to account for the 3-D drift- and mountain-scale dimensionality all within a single monolithic thermohydrologic model. This approach is too computationally expensive to be a viable simulation tool capable of addressing all waste-package locations in the repository. The Multiscale Thermohydrologic Model (MSTHM) is a computationally efficient alternative to addressing these modeling issues. In this paper, we describe the principal calculation stages to predict temperature, relative humidity, and liquid-saturation, as well as other thermohydrologic variables, in the drifts and in the host rock. Using a three-drift repository example (which is a scaled-down version of the proposed repository), we demonstrate the validity of the MSTHM approach against a nested monolithic thermohydrologic model.

Forecasting↗