Biomedical subjects

G N Mercer

Publications and source records attributed to G N Mercer.

3 recordsLinked to original sources

PubMed2005

Modeling thermal burns due to airbag deployment.

Automotive airbags are now a widely accepted safety measure designed to reduce morbidity associated with motor vehicle accidents. Their usage is increasing with multiple airbags (driver, passenger and side curtain) being fitted to many vehicles. However the deployment of airbags has been identified as causing injuries in some instances including minor burns. There are three mechanisms for thermal burns due to an airbag; contact with the hot expelled gases from the airbag, contact with the hot airbag itself and melting of clothing from either of these contacts. A mathematical model is used here to predict the likelihood and severity of the first two types of burns. It is shown that direct contact with high temperature exhaust gases venting from the airbag can indeed lead to burns and that burns from contacting the hot airbag material are possible but far less likely to occur.

Accidents, Traffic↗

PubMed1997

Dynamics of human milk extraction: a comparative study of breast feeding and breast pumping.

We describe a mathematical model of the flow and deformation in a human teat. Our aim is to compare the theoretical milk yield during infant breast feeding with that obtained through the use of a breast pump. Infants use a peristaltic motion of the tongue, along with some suction, to extract milk, whereas breast pumps use a cyclic pattern of suction only. Our model is based on quasi-linear poroelasticity whereby the teat is modelled as a cylindrical porous elastic material saturated with fluid. We impose a cyclic axial suction pressure difference across the teat and impose a radial compressive force moving along the teat which mimics infant suckling. This is compared to the case of cyclic and steady pumping only which models the action of breast pumps. The results illustrate that there is an optimal time to apply the compressive force during the suction cycle that will increase the flow rate in our theoretical teat. The model and results may be of use in the future design of effective breast pumps.

Breast Feeding↗

PubMed1997

Comparing breastfeeding and breast pumps using a computer model.

There is a role for computer models in increasing the understanding of milk extraction from the human teat. A computer model can be used to investigate aspects of extracting milk from the human teat which are not feasible using clinical experiments. In this paper, the behavior of the human teat during an infant suckling and with the use of a breast pump is modeled. The model is used to (1) identify the role of suction and the peristaltic motion of the tongue during suckling and (2) compare the volume of milk extracted by an infant breastfeeding with that obtained using a breast pump. Infants use a peristaltic motion of the tongue, along with some suction, to extract milk. Breast pumps use a cyclic pattern of suction only. In the model, the human teat is represented as a cylindrical porous elastic material saturated with fluid. We mimic an infant suckling by imposing both suction and a peristaltic force in the computer model of the human teat. This is compared to the effect of suction only, which models the action of breast pumps. The results demonstrate that there is an optimal time to apply the peristaltic force during the suction cycle which will increase the milk volume. The model and results may be of use in the future design of effective breast pumps.

Breast Feeding↗