Numerical Estimation of the Thermal Response of Thermal Protective Clothing-Air Gap-Human Skin Micro-system

Thermal protective clothing has been recognized as the primary shielding against emergency fire hazard and inflammable gas leakage. Therefore,the thermal response of human covered with thermal protective clothing under high temperature is the key work to investigate the thermal insulation of thermal protective clothing. A coupling model composed of thermal protective clothing,air gap and human skin is established and the temperature of the micro-system is numerically solved via the finite element method( FEM).Especially,the heat transfer of air gap located between clothing and human skin considering conduction and radiation is established while the human skin layers involve the effect of blood perfusion. Then the effect of thermophysical properties( thermal conductivity and volumetric capacity) of fabric and thickness of fabric and air on the thermal response of the micro-system is elucidated and compared.The results indicate that the volumetric heat capacity of fabric is the key parameter to affect the thermal shielding performance of thermal protective clothing,and the thicker fabric thickness and air gap thickness can improve the thermal protective properties of the micro-system.

The influence of different methods of acupuncture on skin surface perfusion

OBJECTIVE:To compare the effects on the body surface of different kinds of placebo/sham acupuncture with that of traditional needling sensation acupuncture.METHODS:Point Neiguan(PC 6) of 29 healthy subjects,19 males and 10 females,was stimulated with needling sensation,shallow,placebo and deep acupuncture at the non-acupoint.After stimulation with different methods of acupuncture,the change in perfusion of the micrangium in the skin surface around the elbow joint,with Point Quze(PC 3) as its center,was observed with laser Doppler blood-flow imaging.RESULTS:Judging from the absolute value of perfusion of the skin surface micrangium,several methods of acupuncture can cause change in blood flow.The ratio of blood-flow perfusion in the meridian area in and around Quze declined before and after needling insertion in needling sensation acupuncture and shallow acupuncture.This observation did not occur in placebo and non-acupoint acupuncture.Needling sensation acupuncture at an acupoint can relatively reduce the perfusion ofthe micrangium in the projective area of the meridian where the acupoint is located on the body surface(P<0.05),indicating the specificity of meridians.CONCLUSIONS:Stimulation of an acupoint or a point on the body surface with any type of acupuncture can cause change in blood flow in the skin near the needling point.However,the biological mechanism underlying this phenomenon needs to be further explored.