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Biomedical subjects

W C Kaufman

Publications and source records attributed to W C Kaufman.

At least 19 recordsLinked to original sources
PubMed1994

Ballooning.

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Accidents, Aviation↗
PubMed1987

A different approach to wind chill.

In cold regions, "wind chill temperatures" or "wind chill" are regularly used to suggest how the wind-temperature combination may affect comfort or safety. This concept, based on physical studies, is unlikely to provide the most useful information. Humans have no innate temperature sense, and so their response depends not only on physical conditions and physiological state but also on past experience, how they perceive the environment, and how weather conditions differ from the norm. We present wind chill for one north central American city for the winter months and for three north central American communities for the month of February as a frequency table and as it may relate to human perception of cold. We propose that, for any given community, wind-temperature conditions as they may be perceived and how they relate to the norms for that community might add greater meaning to the numerical wind chill temperature.

Air Movements↗
PubMed1987

Pilot studies of vapor transfer through breathable outerwear by simulating sweating in the cold.

Claims that rainproof films allow the unimpeded evaporation of sweat have been examined by modifying a heat transfer method to include evaporation of water. This physical study simulates a casual hiker (2 mets) in 4 degrees C (40 degrees F) dry weather wearing clothing of 1.5-2.0 clo and sweating at 40 g X h-1. Goose down, wool, polyester, and polyolefin fills were combined with no protective cover, Gore-Tex, and polyurethane covers. No significant differences in insulation between dry (control) and wet (stabilized evaporation) occurred. Neither cover nor fill had significant effects on heat transfer. Total water evaporated (sweat produced) was affected only by the wool filler. A significantly greater amount of water was trapped by the natural fibers and the polyurethane cover. These data indicate that breathable rainwear is likely to have little effect on heat transfer, even though it allowed 89% of sweat to evaporate compared to 51% for the polyurethane raincoat.

Clothing↗
PubMed1986

Thermal insulation of materials with possible aerospace application.

Thermal insulation values for several materials that may have aerospace applications have been determined by a single method. Heat transfer across a specimen on a constant temperature heat source was measured by heat flow disc, and temperature on each side of the specimen was measured by thermistor. The data demonstrate that, with various thermal insulating materials, the primary factor in thermal insulation is the entrapped air. Where convective air currents were sufficiently reduced, insulative values for different materials varied only slightly. Reflective and nonreflective materials sandwiched into the insulators made little difference in these experiments, but if employed differently, might increase insulative values significantly.

Aerospace Medicine↗
PubMed1986

Wind chill reconsidered, Siple revisited.

Experiments similar to those establishing the concepts of wind chill have been done with bare and "clothed" cylinders and when the clothing was wet at temperatures above and below freezing. Clothing prevented the heat loss that was associated with increased wind velocity in the bare cylinder. With wet clothing, evaporation increased with wind velocity but heat loss did not, and raincoats or freezing markedly reduced wet heat loss. The concept of wind chill applies only to unprotected objects.

Air Movements↗
PubMed1986

Comparative cold responses of men and women to external and internal cold stimuli.

Experiments were conducted comparing the relative contribution of internal and external cold stimuli in the initiation of horripilation (cutis anserina or "goose flesh") in men and women. Five men and five women were compared. Subjects wore a water perfused vest which covered the entire thorax and allowed torso skin temperature to be maintained at either 34 degrees C, 30 degrees C, 26 degrees C, or 22 degrees C in four separate experiments. After stabilization, the subject's legs were immersed in water maintained at 16 degrees C for 20 min. After removing their legs from the water, subjects then pedalled a stationary bicycle ergometer at minimum resistance to facilitate the return of cooled venous blood to the thoracic core. Horripilation was episodic in both men and women but related significantly to torso skin temperature in men and percent body fat in women over the range of torso skin temperatures tested. There was no significant association between horripilation episodes and either the stabilization, immersion, or minimal exercise phase of the experiment. Core body temperature, as measured by rectal and esophageal thermistors, decreased significantly in men from 37.0 degrees C and 36.6 degrees C at 34 degrees C torso skin temperatures, but remained unchanged in women. The results suggest that skin cooling initiates horripilation whose occurrence and pattern are affected by different combinations of morphological or physiological variables in men and women.

Adult↗
PubMed1985

Thermal insulating capabilities of "thin" clothing insulation.

Claims have been made that certain "thin" polyolefin clothing insulating materials possess superior insulating capabilities because they consist of extremely fine fibers. In a comparative study, swatches of the usual clothing materials, down, polyester, and polyolefin were examined by a technique that allowed two methods of calculating the insulation value, one across the sample and the second from the inner surface of the sample to the ambient air. The second method produces a value that includes the air layer which adheres to all clothing, increasing the apparent insulation. The thermal insulation of the material, per se, does not change. The data demonstrate that the claims can be made for any thin insulation.

Air↗