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Biomedical subjects

E Kamon

Publications and source records attributed to E Kamon.

At least 37 records · Page 2Linked to original sources
PubMed1979

Wind speed limits to work under hot environments for clothed men.

Four heat-acclimated clothed young adult men exercised (treadmill) at metabolic rate of 191 W.m-2 (27% VO2 max), under five air temperatures (Ta) between 36 and 53 degrees C and three wind velocities (v), 1, 2, and 4 m.s-1, for 2 h. The 2nd h of each experiment involved progressive increases in the ambient vapor pressure (Pa) to force an upward inflection of the rectal temperature (Tre). The Tre point of inflection identified the critical Pa (Pcrit) for each Ta. The average mean skin temperature (Tsk = 36 degrees C for all Pcrit. Straight-line isotherms for Tsk = 36 degrees C, which agreed with the negative regressions of the Pcrit on Ta, represented the limits of exposure for Ta less than or equal to 44 degrees C. The slope characteristics of the isotherms corresponded with skin wettedness (w) of 0.94, 0.71, and 0.58, respectively, for v of 1, 2, and 4 m.s-1. For Ta greater than 44 degrees C the limit line corresponded with steeper negative regressions indicating a lower w than for Ta less than or equal to 44 degrees C. Despite the increase in the ambient evaporative capacity due to the higher v the limit lines describing exposure limits were not significantly different either at Ta less than or equal to 44 degrees C for v of 2 and 4 m.s-1 or at Ta greater than 44 degrees C for all three v.

Acclimatization↗
PubMed1979

A dryer for rapid response on-line expired gas measurements.

A dryer is described for use in on-line breath-by-breath gas analysis systems. The dryer continuously removes water vapor by condensation and controls the sample gas at 2 degrees C dew-point temperature or 5 Torr water vapor partial pressure. It is designed to operate at gas sampling flow rates from 0.5 to 1 1.min-1. The step-response time for the described system including a Beckman LB-2 CO2 analyzer, sampling tubing, and dryer is 120 ms at 1 l.min-1. The time required for gas samples to transport through the dryer is 105 ms at a gas sampling-flow rate of 1 l.min=1.

Desiccation↗
PubMed1978

In-plant evaluation of the muscle strength of workers.

The static muscular strength of the back extensors, arm flexors and hand grip were measured on industrial workers (463 men and 139 women) involved in physically demanding jobs. No significant differences in strength were found among workers on different jobs. However, strength differences were evident with respect to age and sex; women were about 60 percent as strong as men, and men below 31 years of age were stronger than men above this age.

Adult↗
PubMed1978

Physiological and biophysical limits to work in the heat for clothed men and women.

Heat-acclimated, lightly clothed men and women (four of each) walked on a treadmill at 25% and 43% VO2 max, respectively, (M =194 W.m-2), under seven air temperatures (Ta) ranging from 36 to 52 degrees C. Each experiment involved 1 h of fixed and a 2nd h of progressively increasing ambient vapor pressure (Pa). The relative steady state of rectal temperature (Tre), mean skin temperature (Tsk), and heart rate (HR) reached in the 1st h were forced upward during the 2nd h by the rising Pa. The critical air vapor pressure (Pcrit) was identified by the Tre point of inflection for each Ta. One man did not fully reach steady state, but inflection could be determined for his physiological responses. The mean values of all points of inflection were calculated for Tre, Tsk, and HR. Significant sex difference in HR was found only by excluding the results of the one man. Tre and Tsk showed no significant difference between men and women. The coefficient for evaporative heat transfer (he), which could be derived using the Pcrit for the low Ta range, was 14.5 +/- 2.2 W.m-1 Torr-1.

Acclimatization↗
PubMed1977

Evaluation of Federal man tests for self-contained breathing apparatus.

The transient pulmonary responses to four short duration man tests used in the Federal approval of breathing apparatus were measured. The pulmonary ventilation dropped 30 percent in the first thirty seconds in the periods assigned for samples and readings which were immediately preceded by work. A physiological deficit was incurred during the short duration man tests which meant that less O2 and ventilation were required when compared to steady state responses shown on approval tests. The scheduled man test activities for short duration breathing apparatus should be revised and made more vigorous to match the intended use of escape apparatus.

Adult↗
PubMed1976

Physiologic limits to work in the heat and evaporative coefficient for women.

Ten heat-acclimated females exercised seminude on a treadmill at 30% Vo2 max (M=152 W-m-2) under eight air temperatures (Ta) ranging from 30 degrees C to 52 degrees C. Each experiment involved 1 h of fixed and a 2nd h of progressively increasing water vapor pressure (Pw) with either air movement of 1 m-s-1 or still air. The equilibrium values of rectal temperature (Tre), mean skin temperature (Tsk),and heart rate (HR) reached in the 1st h were forced upwards in the 2nd h by the rising Pw. The critical Pw was defined by the Tre inflection point for each Ta. The loci of the critical Pw were used to delineate the thermal limits on the psychrometric chart and were used to derive the effective evaporative coefficient (Ke') applicable to the ambient capacity for evaporative cooling (Emax). The derived Ke' was 17.6 +/- 4.2 W-m-2 (mean +/- SD) for v0.6m-s-1. Isotherms constructed on the basis of the obtained Ké, Tsk, and sweating capacity were higher than the physiologically based Pw limits.

Adaptation, Physiological↗
PubMed1976

Acclimation processes by daily exercise stints at temperate conditions followed by short heat exposures.

In order to improve the conventional procedures for heat acclimation by making the process shorter and more efficient, four daily regimens of 30 min of exercise under temperate ambient conditions (22 degrees C) followed by a 30-min walk (5.6 km/hr under hot dry ambient conditions (50 degrees/25 degrees C, Tdb/Twb) were administered to three groups of subjects. The respective exercise part for each group was as follows: 1) 30 min of descent on a laddermill (negative work); 2) 30 min of ascent on a laddermill (positive work), and 3) 15 min of descent followed by 15 min of ascent on the laddermill. The four daily regimens of exercise and heat exposure were followed by four consecutive daily walks of up to 120 min in dry heat. A fourth control group was not subjected to the special acclimation regimen, but underwent the eight daily conventional acclimation procedures. Acclimation was judged by the increase in tolerance time (T) for the walk in the heat and decrease in heart rate (HR) rectal temperature (Tre) and mean skin temperature (Tsk). Partial acclimation was observed after the 4 d of the regimen for the three experimental groups and the 4 d of the conventional procedure on the fourth control group. The final state of acclimation was apparent on the eighth day for all four groups. When the partial acclimation after the 4-d regimen was compared to the final state of acclimation, the following improvements were observed: 90% increase in T; 72% decrease in HR; 56% decrease in Tre, and 45% fall in Tsk. These improvements were similar to those observed after the 4 d of the conventional treatment on the control group as well as to those reported by others.

Acclimatization↗
PubMed1975

Steady state respiratory responses to tasks used in Federal testing of self-contained breathing apparatus.

A portion of Title 30, Part II, CFR calls for a Man Test, which is a series of regimens performed with a breathing apparatus. The respiratory responses to the tasks in the Man Test were established on coal miners and students. Based on these responses, the minimal metabolic requirements were derived for the use of breathing apparatuses with a service life of 30 minutes or more.

Coal Mining↗
PubMed1975

Ergonomics of heat and cold.

The biophysical, physiological and some of the psychological aspects of work under unfavorable man-made ambient conditions are presented in light of the need to prevent excessive strain. Work is treated in two ways: 1) in terms of the muscles O2 demand as a fraction of maximal aerobic capacity; and 2) in terms of metabolic heat source. Since maximal aerobic capacity depends on factors such as physical fitness, age and sex, these factors require consideration in estimating strain due to work. The absolute metabolic heat (M) produced during work is needed in the consideration of the total heat balance. Radiation (r), convection (C), and, under some circumstances, evaporation (Eev) are the main avenues of heat exchange between man and his immediate environment. Eev is primarily a function of the ambient potential for evaporation (Emax). Since the relation of the sum M+R+C to Emax determines heat balance when man in under a heat load, evaluation of the avenues of heat exchange, the sources of heat load, and the stressing effect of all these on the physiological responses are treated in some detail. Psychrometrically defined limits of exposure are also discussed. Subjective sensation and mental performance are discussed in light of their correlation with physiological responses to heat. Cold is treated mainly from the point of view of safety and protective clothing.

Acclimatization↗
PubMed1975

Long-term mortality experience of steelworkers. VIII. Mortality patterns of open hearth steelworkers (a preliminary report).

The findings in this report of a deficit in mortality from cardiovascular diseases and an excess in diseases of the digestive system among open hearth workers indicate the need for further study of men working in hot environments. In future reports we hope to refine the comparisons by obtaining data which will enable classification of workers more precisely by intensity and duration of exposure within the open hearth. Of particular importance in future work are the evaluation of possible relationships between the actual levels of heat exposure and subsequent morbidity and mortality, as well as possible interactions between heat stress and physical exertion in terms of the incidence of heart disease and other select diseases.

Alloys↗