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Factors Affecting the Design of an Air Conditioning and Pressurizing System: The Desirable conditions from the Point of View of Comfort of Passengers Approached from the Physiological Aspect

01 Mar 1949-Aircraft Engineering and Aerospace Technology (MCB UP Ltd)-Vol. 21, Iss: 3, pp 86-91
TL;DR: The body temperature is the result of the automatic balancing of this heat production, which is more than the amount needed to keep the body warm, and the heat loss from the body.
Abstract: IN designing for passenger comfort in modern commercial aircraft, many laboratory tests and research investigations have shown that the fundamental requirement for human comfort is physiological, and can be summed up by saying that the optimum conditions for comfort are those existing when the body can maintain complete thermal equilibrium, with only minor adjustments in the heat regulating mechanism of the body. Heat is produced in the human body by the process known as metabolism, in which food is oxidized, or absorbed, by the cells in the body. The body temperature is the result of the automatic balancing of this heat production—which is more than the amount needed to keep the body warm—and the heat loss from the body. Heat is lost by radiation, convection, and evaporation. The radiation loss is dependent upon the skin, or clothing, temperature, and also the temperature of any surrounding surfaces. The convective heat loss is a function of air velocity over the body and a positive temperature differential between the skin, or clothing temperature, and that of the surrounding atmosphere. The evaporative loss is a function of temperature, velocity, and humidity, and takes place when the partial pressure of the water vapour in the surrounding air is less than the pressure of the moisture on the skin, or in the lungs.
Citations
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Dissertation
31 Aug 1962
Abstract: approved The effects upon man of the environment in which he exists have long been of interest to investigators. The intent of this study was to determine the dominant environmental factors influencing mental and motor performance, and to investigate the existence of interaction between environmental factors. Since the performance requirements involved in operating a console are representative of numerous manmachine operations, measurements were made of the mental and motor tasks involved in such an operation. A console requiring several cue and response operations was constructed. The cue sequences were programmed to be repeated and the responses were automatically recorded. Cues included dials, gauges, and flashing and colored lights. Responses required manipulation of a foot pedal, push buttons, and a toggle switch. The console panel was designed according to accepted recommendations for optimum performance. The operator's chair was completely adjustable. In addition to operating the console, a subject being tested was also required to work on a written test. This test was designed to measure speed and accuracy of work, not intelligence. The written test was given to a large control group before being used in the experiment. aj o /profes sor An environmental chamber was constructed to house the console operation. The chamber provided means for exposing the console operator to desired levels of noise, illumination, temperature, and motion. Two levels of each of the environmental factors were used. One level was based on commonly acceptable standards of normal working conditions. The other level was established at a point previous investigations had determined to be detrimental to performance. These levels were random noise at 35 to 40 decibels and 83 to 85 decibels, illumination at 5 footcandles and 74 foot candles, effective temperatures of 68 to 70° F and 86 to 88° F, and no motion at one level to a random motion varying from very slight movement to a maximum tilt of 15 degrees. Subjects for the experiment were volunteers from the Naval Reserve Officers Training Course. These subjects constituted a group of known minimum intelligence and physical condition. The experiment was conducted by exposing a subject to the eight possible environmental combinations at one temperature during each of two sessions. Analysis of mental and motor scores were made by normal statistical procedures. Twelve replications were used. The following conclusions were obtained from analysis of the data taken during the experiment For the environmental factor levels tested of motion, noise, illumination, and temperature, the motion factor appears dominant in adversely affecting motor performance. In the situation where cues to motor performance depend on visual discrimination, the level of illumination is also significant. There was no evidence of environmental interaction effects on motor performance. Two interactions among the 22 interactions evaluated for mental performance were found to be above the 5% significance level. These interactions were temperature noise and temperature -illumination. Depending upon the time of exposure, high mental performance resulted when either low level of noise or illumination combined with low temperature and when either high level of noise or illumination combined with high temperatures. Temperature was the key factor in evaluating the effects of interaction on mental performance. Depending upon the time of exposure, high mental performance resulted when either low levels of noise or illumination combined with low temperature and when either high levels of noise or illumination combined with high temperatures. INFLUENCE OF ENVIRONMENTAL FACTORS ON HUMAN MENTAL AND MOTOR PERFORMANCE IN CONSOLE OPERATIONS

4 citations

References
More filters
Dissertation
31 Aug 1962
Abstract: approved The effects upon man of the environment in which he exists have long been of interest to investigators. The intent of this study was to determine the dominant environmental factors influencing mental and motor performance, and to investigate the existence of interaction between environmental factors. Since the performance requirements involved in operating a console are representative of numerous manmachine operations, measurements were made of the mental and motor tasks involved in such an operation. A console requiring several cue and response operations was constructed. The cue sequences were programmed to be repeated and the responses were automatically recorded. Cues included dials, gauges, and flashing and colored lights. Responses required manipulation of a foot pedal, push buttons, and a toggle switch. The console panel was designed according to accepted recommendations for optimum performance. The operator's chair was completely adjustable. In addition to operating the console, a subject being tested was also required to work on a written test. This test was designed to measure speed and accuracy of work, not intelligence. The written test was given to a large control group before being used in the experiment. aj o /profes sor An environmental chamber was constructed to house the console operation. The chamber provided means for exposing the console operator to desired levels of noise, illumination, temperature, and motion. Two levels of each of the environmental factors were used. One level was based on commonly acceptable standards of normal working conditions. The other level was established at a point previous investigations had determined to be detrimental to performance. These levels were random noise at 35 to 40 decibels and 83 to 85 decibels, illumination at 5 footcandles and 74 foot candles, effective temperatures of 68 to 70° F and 86 to 88° F, and no motion at one level to a random motion varying from very slight movement to a maximum tilt of 15 degrees. Subjects for the experiment were volunteers from the Naval Reserve Officers Training Course. These subjects constituted a group of known minimum intelligence and physical condition. The experiment was conducted by exposing a subject to the eight possible environmental combinations at one temperature during each of two sessions. Analysis of mental and motor scores were made by normal statistical procedures. Twelve replications were used. The following conclusions were obtained from analysis of the data taken during the experiment For the environmental factor levels tested of motion, noise, illumination, and temperature, the motion factor appears dominant in adversely affecting motor performance. In the situation where cues to motor performance depend on visual discrimination, the level of illumination is also significant. There was no evidence of environmental interaction effects on motor performance. Two interactions among the 22 interactions evaluated for mental performance were found to be above the 5% significance level. These interactions were temperature noise and temperature -illumination. Depending upon the time of exposure, high mental performance resulted when either low level of noise or illumination combined with low temperature and when either high level of noise or illumination combined with high temperatures. Temperature was the key factor in evaluating the effects of interaction on mental performance. Depending upon the time of exposure, high mental performance resulted when either low levels of noise or illumination combined with low temperature and when either high levels of noise or illumination combined with high temperatures. INFLUENCE OF ENVIRONMENTAL FACTORS ON HUMAN MENTAL AND MOTOR PERFORMANCE IN CONSOLE OPERATIONS

4 citations