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High indoor temperatures in modern stables of livestock farming units have to be offset to avoid loss in animal performance, and this is possible only through improved heat emission of the organism. Increase in air movement, for the time being, is the most effective method. A theoretical account is given of the amount of air movement required in temperatures above optimum and compared with literature data.
An experiment using 4,800 commercial broiler males (Ross x Ross) was conducted in 12 climatic chambers. Three levels of relative humidity (RH) (45, 40, to 80, and 75%) and two levels of internal air circulation (7.7 to 9.9 and 17.8 to 24.5 cm/s), with each level replicated and, therefore, forming a 3 x 2 x 2 factorial arrangement of treatments, arrangement of treatments, were imposed as the main effects. Broilers were group weighed and feed efficiencies calculated at 14, 28, and 42 days of age. Percentage dry matter of the litter and a subjective evaluation of general litter conditions (moisture and caking) were scored weekly, with the percentage nitrogen and total quality of litter produced in each chamber measured at the conclusion of the study. Ammonia levels were measured in each chamber every second day. A sample of birds (36) from each chamber was processed at 42 days and scored for litter spots and ammonia burns on the breast and for the incidence and severity of twisted legs, crooked toes, and infected and calloused hocks and foot pads. Mean body weight was significantly greater (32 g) at 42 days of age in birds exposed to 45% RH compared with the two higher regimens of RH. Both the incidence and severity of ammonia burns on the breast and infected foot pads were significantly higher with 75 versus 45% RH. Increases in RH significantly increased caking and litter moisture and reduced the percentage of dry matter and the percentage of nitrogen found in the litter. Ammonia levels were more variable but generally increased with increases in RH. The two levels of air movement within the chambers produced less influence on the environment than RH, although the scores for both litter moisture and caking were significantly lower with increased levels of internal air circulation.
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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).
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.
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.
Evaluation of indoor air pollution problems requires an understanding of the relationship between sources, air movement, and outdoor air exchange. Research is underway to investigate these relationships. A three-phase program is being implemented: 1) Environmental chambers are used to provide source emission factors for specific indoor pollutants; 2) An IAQ (Indoor Air Quality) model has been developed to calculate indoor pollutant concentrations based on chamber emissions data and the air exchange and air movement within the indoor environment; and 3) An IAQ test house is used to conduct experiments to evaluate the model results. Examples are provided to show how this coordinated approach can be used to evaluate specific sources of indoor air pollution. Two sources are examined: 1) para-dichlorobenzene emissions from solid moth repellant; and 2) particle emissions from unvented kerosene heaters. The evaluation process for both sources followed the three-phase approach discussed above. Para-dichlorobenzene emission factors were determined by small chamber testing at EPA's Air and Energy Engineering Research Laboratory. Particle emission factors for the kerosene heaters were developed in large chambers at the J. B. Pierce Foundation Laboratory. Both sources were subsequently evaluated in EPA's IAQ test house. The IAQ model predictions showed good agreement with the test house measurements when appropriate values were provided for source emissions, outside air exchange, in-house air movement, and deposition on "sink" surfaces.
Experiments using excised canine larynges and experimental air tract fluid were conducted to clarify the movement of air tract fluid in association with vocal fold vibration by means of X-ray stroboscope system. It was thought that the movement of air tract fluid in lubricating of the larynx during phonation was closely correlated to vocal fold vibration, especially the wave motion of the mucous membrane of the vocal folds and the movement of air tract fluid on the glottis might be one of parameters to evaluate the flexibility of the mucous membrane of the vocal folds.
Experiments were conducted simultaneously with gas and particle tracers to determine the relative loss of particles between source and recipient sites in the hospital ward units. The magnitude of this loss could be accounted for by the assumption of sedimentation from well-mixed air masses during the time required for movement between source and recipients sites. As a consequence of this loss the degree of isolation between patient rooms for airborne particles was between 4 and 25 times greater than that for gaseous contamination, which reflects the actual transport of air between the rooms. The design and construction of portable spinning-disk particle generators suitable for field studies is discussed.
The movement of chlorpyrifos and diazinon from cracks and crevices in empty dormitory rooms with and without forced air movement to houseflies and plates in non-target areas was studied. Aluminum pie plates in rooms with the high concentrations of an insecticide, no forced air movement, and at the earlier sampling interals contained more insecticide. Insecticides were not detectable at 48 hr. Increased housefly movement occurred simultaneously with the initiation of insecticide application in rooms with forced air and 1 min later in rooms with no forced air. Mortality of houseflies exposed during and at 5 hr after insecticide application was greater for males than females in all tests except one; at the high insecticide concentrations; and at successive time intervals through the 24-hr interval after their transfer from the treated rooms to holding rooms. Houseflies in cages near the ceiling, exposed to an insecticide, and forced air movement, exhibited greater mortality than those in cages on the floor, while the reverse was true for houseflies in rooms with no forced air movement.
The reliability of parameters used to assess pediatric postextubation upper respiratory distress is unknown. We prospectively studied the interobserver reliability of six parameters commonly used to assess respiratory distress in children. Eligible patients were less than 15 years old and hospitalized for traumatic injuries at Harborview Medical Center between March and September 1989. At extubation, patients were examined independently by a physician, a nurse, and a respiratory therapist, each of whom evaluated respiratory rate (RR), stridor, air movement, flaring/retractions (F/R), level of consciousness (LOC), and oxygen saturation (O2 sat). Reliability was measured by percentage agreement and weighted kappa (Kw). The 25 children (27 extubations) had a median age of 7 years, and eight of the 27 required treatment for upper airway obstruction. Percentage agreement ranged from 82% (for air movement) to 96% (for O2 sat). Weighted kappas were excellent for RR and F/R (Kw greater than .6); moderate for LOC, stridor, and O2 sat (0.4 less than Kw less than .06); and poor for air movement (Kw less than .4). Further improvements in interobserver agreement are required to provide more consistent upper airway management in critically ill children.
Following the commissioning of a new suite of operating rooms air movement studies showed a flow of air away from the operating table towards the periphery of the room. Oral microbial flora dispersed by unmasked male and female volunteers standing one metre from the table failed to contaminate exposed settle plates placed on the table. The wearing of face masks by non-scrubbed staff working in an operating room with forced ventilation seems to be unnecessary.
An experiment was carried out in a reconstructed building for cell-battery rearing of young pigs, heated by two petroleum calorifers. Six to eight pigs were placed in a cell in 4 row-cell batteries at two storeys. Ventilation was realized by sucking ventilators, situated along the ridge of the building. Temperature and relative air humidity were measured at 7, 14 and 21 o'clock. The gas composition and the air movement rate were periodically investigated. It was established that at temperatures in the region below 0 degrees C regime for that category of pigs cannot be maintained with the accepted heating constructions. The gas composition standards established and the rate of air movement are within the range of hygienic standards. At the level of the second cell and crosswise to the building slighter temperature differences were observed and the temperature was higher. The conclusion is made that the chosen ventilation scheme and equipment for heating do not ensure optimal and uniform temperature-moisture regime in the premises.
To perform blind nasotracheal intubation, the physician feels or listens for air movement through the endotracheal tube to facilitate the tube's passage into the trachea. The tube whistle is a device that attaches to the endotracheal tube adapter and produces whistle sounds of different pitches during inspiration and expiration, enhancing the detection of air movement and possibly allowing for easier intubation. This article describes the use of the whistle and presents information collected from a nine-month prospective study of the endotracheal tube whistle.
The authors have determined the coefficient of evaporative heat loss of the human body (he) by means of humidity steps in low air movement (Va less than or equal to 0,2 m/s). Such a determination requires a fully wetted skin and this implies therefore some loss of dripping sweat. The collection of this dripping sweat allows the determination of the total evaporation: this evaporation exists on the skin surface and around the drops during their fall from the skin to the oil pan where dripping sweat is collected. An estimation of this dripping sweat evaporation allows to assess the skin evaporation and, consequently, the evaporative coefficient he. In these experimental conditions: E = S - SNE - 0,0005 SNE (PsH2O - PaH2O) where E is the skin evaporative rate (g/h);S = total sweat rate (g/h);SNE = the nonevaporative sweat rate (g/h);PaH2O = the partial pressure of saturated water (at Ts) on skin (mb) and PaH2O the partial pressure of water vapor in ambient air (mb). The coefficient of evaporative heat loss in low air movement thus found, is 5,18 +/- 0,22 W/m2-mb.
An equation based on heat transfer theory is developed to predict the rate of heat loss from a homeothermic vertebrate to the environment, specified by the air temperature, humidity, windspeed and radiation receipt. The analysis incorporates the animal's thermoregulatory responses--sweating ability, vasomotor action, and regulation of body-core temperature, metabolic and respiratory rate. The loss of heat and water vapour from cattle is used as an illustration, and particular attention is given to their heat balance in hot environments. The predicted rates of heat loss from cattle indoors at various air temperatures and humidities are consistent with experiments. Outdoors, intercepted solar radiation can reduce substantially heat loss through the body tissue when the air temperature is low. In contrast, at high air temperatures the heat dissipation may not be sensitive to the radiation load, although body-core temperature is. Increased rates of air movement can aggravate strain at low air temperatures, but mitigate strain in a hot environment.