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PubMed1975

Determination of air movement in stored grain as a factor in dynamic dispersion and distribution patterns of gaseous pesticides (fumigants).

The new research reported herein was motivated by variations in distribution-persistence patterns of fumigant residues (BERCK, 1974). The current developmental program is still underway. In the meantime, measurement of picoliter amounts of SF6 in air by GC equipped with a Ni63 EC detector has been proven useful over an airflow range of 10(-4) to 50 mph, representing a factor of 500,000 in differences in air velocity. Diverse applications have been outlined herein. This is the first case on record where measurement of unassisted airflow in the interstitial air of stored grain has been successfully executed, and which enabled determination of airflow speeds in the range of 0.5 to 7.5 times 10(-4) mph (=3 to 45 inches per hour).

Air Movements↗
PubMed1987

Effect of air movement on operant heat demand of chicks.

Chicks, 8 days of age, were housed in a wind tunnel at temperatures from 12 to 28 C in increments of 4 C. The tunnel was equipped with a microswitch, an infrared bulb located above the switch, and a small electric fan controlled by a rheostat. Following learning, chicks were exposed at each temperature to air speeds of 0, .5, 1.0, and 1.5 m/s according to a Latin-square design. Chicks readily responded to air speed and temperature changes. For each increase of .1 m/s the effective environmental temperature dropped .6 C.

Air Movements↗
PubMed1994

Influence of air movement, facemask design and exercise on upper airway, transpulmonary, and transdiaphragmatic pressures in thoroughbred horses.

The influences of facial airflow, exercise and wearing a facemask on gas exchange and upper airway (Pu), transpulmonary (PTP) and transdiaphragmatic (PTD) pressures were investigated in 6 horses performing an incremental exercise test on an inclined (10%) treadmill. The test consisted of a 2 min walk followed by two 2 min exercise bouts at intensities which produced 40% and 80% of maximal oxygen consumption. Horses performed the test 4 times, once for each of 4 protocols, which involved not wearing a facemask (A), wearing a mask with either no biased flow through it (B), with an expiratory bias of 6300 L/min through it (C), or with an inspiratory bias of the same magnitude (D). Although no statistically significant differences in arterial blood gases, Pu, PTP, or PTD could be attributed to the various protocols, trends that may have been physiologically important were detected. Hypoxemia and hypercapnia associated with exercise were most marked with protocol B and least severe with protocols A or D. PTP was lowest for all tests with protocol D. Of the 3 conditions that required the wearing of a mask, protocol D was associated with the lowest Pu. While impelling air into the respiratory tract, as presumedly occurs with horses exercising over ground, may enhance respiratory function during exercise, this preliminary study does not clearly demonstrate this. Because this is an important consideration when conducting studies involving horses on treadmills, further investigations at higher exercise intensities and with additional methodologies are needed to clarify the issue.

Acid-Base Equilibrium↗
PubMed1980

Air movement and heat loss from sheep. I. Boundary layer insulation of a model sheep, with and without fleece.

A model sheep, made from metal cylinders and hemispheres, was heated electrically. Heat loss by forced convection in a wind tunnel was analysed in terms of the dependence of the Nusselt number (Nu) on Reynolds number (Re). For a bare trunk Nu = 0.095 Re0.684, but with fleece covering the trunk to a depth of 3.5 cm, Nu = 0.0112 Re0.875 when the mean radiative temperature of the the coat was taken as the surface temperature. Heat transfer by convection from the whole body, including legs, was described by Nu = 0.029 Re0.80. However, a bulk Nesselt number should not be used to estimate heat loss from a live sheep in a hot environment if the windspeed is below about 4 m s-1 because the relation between mean surface temperature, Nusselt number and convective heat flux is not unique.

Air Movements↗
PubMed1980

Air movement and heat loss from sheep. II. Thermal insulation of fleece in wind.

Penetration of an animal's coat by wind reduces its thermal insulation and increases heat loss to the environment. From studies of the sensible heat loss from a life-sized model sheep covered with fleece, the average fleece resistance -rf(s cm-1) was related to windspeed u (m s-1) by 1/-rf(u) = 1/-rf(0)+cu, where c is a dimensionless constant. As c is expected to be inversely proportional to coat depth l, the more general relation -k(u) = -k(0)+c'u was evaluated, where -k = l/-rf is the thermal diffusivity (cm2 s-1) of the fleece and c' = cl is another constant (cm). The orientation of the model to the wind had little effect on the bulk resistance of the fleece, but the resistance on the windward side was substantially lower than on the leeward side.

Air Movements↗
PubMed1980

Air movement and heat loss from sheep. III. Components of insulation in a controlled environment.

The rate of sensible heat loss from a Clun Forest ewe was studied at several fleece depths in a temperature-controlled chamber. A simple resistance analogue was used to describe the heat flow from different body regions. Heat loss from the trunk depends largely on the mean fleece depth l. The fleece resistance was about 1.5 s cm-1 per centimetre depth. Heat transfer through the fleece was accounted for by molecular conduction, thermal radiation and free convection. The fleece conductivity -kb attributed to free convection depends on the mean temperature difference (-Tst---Tct) across the fleece according to the relation -kb = 8.0 (-Tst---Tct)0.53. Estimates of the sensible heat flux from the trunk at environmental temperatures, Ta, between 0 and 30 degrees C range from about 8 W (l = 7.0 cm, Ta = 30 degrees C) to about 160 W (l = 0.1 cm, Ta = 0 degrees C). In contrast, the sensible heat loss from the legs depends mainly on the local tissue resistance. For environmental temperatures between 0 and 30 degrees C, the calculated tissue resistance for this region of the body varied from about 8 to 1 s cm-1. The corresponding heat loss from the legs was between 10 and 20 W, compared with between 3 and 7 W from the head. The fastest heat loss from the legs occurred at an environmental temperature of about 12 degrees C. Although the proportion of the heat loss from the extremities depends on environmental temperature, the total heat loss (sensible or latent) was closely related to the mean skin temperature of the trunk.

Air Movements↗
PubMed1977

Traumatic eye and intracranial air-movement from a subconjunctival to an intracranial position.

In a 12-year-old boy, air accidentally introduced subconjunctivally from the pointed tip of an air compressor hose, moved to an intracranial position over the sella turcica as demonstrated by x-ray films. The globe and a portion of the optic nerve were also outlined by air contrast. A minor corneal abrasion and traumatic iritis cleared promptly and no fractures or other damage occurred.

Brain↗
PubMed1984

The psychological effects on man of air movement and the colour of his surroundings.

The psychological microclimate is a term which is used to describe the specific psychological effects of some environmental agents as well as the psychological effects of other factors of the physical environment (e g, colour of surroundings, etc). This paper considers air motion and colour schemes of space, defines their stress and strain factors, describes the psychological effects - post-strain, and the methodology of their investigation. It further suggests the criteria and limiting and optimum values of the dynamic effect of air (permissible air velocities in interior and exterior environments) and the colour scheme of space (in accordance with the Tektronix standard). In conclusion the paper sums up the possibilities of optimisation of the 'psychological microclimate'.

Journal Article↗