Proceedings of the Institution of Mechanical Engineers. Part H, Journal of engineering in medicine
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Proc Inst Mech Eng H · Jan 2002
Comparative StudyPrediction of skin burn injury. Part 2: Parametric and sensitivity analysis.
Part 2 of this paper presents an analysis of variance (ANOVA) for investigating the precedence of the various parameters, and the effects of varying these parameters, in assessment of burn injury resulting from the exposure of skin surface to heat sources. A one-dimensional model based on the finite difference method (FDM), as implemented in a spreadsheet software application, is applied to the assessment of burn injury. Henriques' theory of skin burns is used for determining the spatial and temporal extent of tissue damage. ⋯ It was also found that fat thermal conductivity and blood perfusion rate have no obvious effect on injury threshold. A two-dimensional analysis was further conducted to determine the sensitivity of the predicted injury to the values of frequency factor, P, and apparent activation energy, deltaE, used in the models. Part 1 of this study details the development of the computer models based on the one- and two-dimensional bioheat equations.
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Proc Inst Mech Eng H · Jan 2002
Comparative StudyPrediction of skin burn injury. Part 1: Numerical modelling.
Skin burn injury and heat tolerance in man is a complex interaction of physical heat exchange processes and the potential for physiological adjustments. In recently developed one-dimensional finite difference and two-dimensional finite element bioheat transfer based numerical models of the skin, the prediction of the thermal efficacy of cooling treatment was evaluated. With the use of a standard Arrhenius model for damage rate, the extent of burn injury was computed from the transient temperature solution. ⋯ Numerical data obtained in the current study suggest that non-thermal factors must be considered in the calculation of the efficacy of postburn cooling therapy. However, when dealing with living tissue, any numerical model can provide only an approximation to conditions in real exposures. Together with analysis of variance, the models were used for investigating the precedence of the various parameters and the effects of varying these parameters on assessment of burn injury resulting from exposure of skin surface to heat sources (Part 2).
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Proc Inst Mech Eng H · Jan 2002
Patient-specific spine models. Part 1: Finite element analysis of the lumbar intervertebral disc--a material sensitivity study.
If patient-specific finite element models of the spine could be developed, they would offer enormous opportunities in the diagnosis and management of back problems. Several generic models have been developed in the past, but there has been very little detailed examination of the sensitivity of these models' characteristics to the input parameters. This relationship must be thoroughly understood if representative patient-specific models are to be realized and used with confidence. ⋯ All loading modes were sensitive to the annulus properties with stiffnesses varying by up to +/-16 per cent. The model also revealed that for a particular compressive deformation or flexural or torsional rotation, the disc bulge was not sensitive to any of the material properties over the range of properties considered. The annulus stresses did differ significantly as the material properties were varied (up to 70 per cent under a compressive load and 60 per cent during disc flexion).