Simultaneous control of temperature and humidity in a confined space. II - Feedback control synthesis via classical control theory.
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Nakanishi, E.↗
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The Temperature-Humidity Infrared Radiometer (THIR) experiment
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Mcculloch, A. W.↗
Membrane humidity control investigation
The basic performance data on a hollow fiber membrane unit that removes water from a breathing gas loop by diffusion is presented. Using available permeability data for cellulose acetate, a preliminary design was made of a dehumidifier unit that would meet the problem statement.
Elam, J.↗
An iterative scheme for determining sea surface temperatures, temperature profiles, and humidity profiles from satellite-measured infrared data
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Chow, M.-D.↗
Desiccant humidity control system
A water vapor and carbon dioxide sorbent material (designated HS-C) was developed for potential application to the space shuttle and tested at full scale. Capacities of two percent for carbon dioxide and four percent for water vapor were achieved using space shuttle cabin adsorption conditions and a space vacuum for desorption. Performance testing shows that water vapor can be controlled by varying the air process flow, while maintaining the ability to remove carbon dioxide. A 2000 hour life test was successfully completed, as were tests for sensitivity to cleaning solvent vapors, vibration resistance, and flammability. A system design for the space shuttle shows a 200 pound weight advantage over competitive systems and an even larger advantage for longer missions.
Lunde, P. J.↗
Summary report on effects at temperature, humidity, and fuel-air ratio on two air-cooled light aircraft engines
Five different engine models were tested to experimentally characterize emissions and to determine the effects of variation in fuel-air ratio and spark timing on emissions levels and other operating characteristics such as cooling, misfiring, roughness, power acceleration, etc. The results are given of two NASA reports covering the Avco Lycoming 0-320-D engine testing and the recently obtained results on the Teledyne Continental TSIO-360-C engine.
Kempke, E. E., Jr.↗
Microwave sensing of atmospheric temperature and humidity from satellites
A 5-channel microwave spectrometer (NEMS) carried on the Nimbus 5 satellite has been taking scans near the 22.235 GHz water vapor resonance and 60 GHz oxygen absorption complex for over 2 years; spectral measurement techniques are described at length. NEMS determinations of atmospheric temperature profiles over 0 to 20 km, and of precipitable water vapor and liquid water over oceans, are compared to relevant radiosonde data and to data reported in analyses by the U.S.A. National Meteorological Center. Some discrepancies between theoretical prediction and empirical evidence are reconciled by examining effects of atmospheric fluctuations. The radiosonde data respond to local fluctuations and do not yield true averages over the large areas sensed remotely by the NEMS.
Staelin, D. H.↗
CO2 and humidity removal system for extended Shuttle missions - CO2, H2O, and trace contaminant equilibrium testing
The equilibrium relationships for the co-adsorption of CO2 and H2O on an amine coated acrylic ester are presented. The equilibrium data collection and reduction techniques are discussed. Based on the equilibrium relationship, other modes of operation of systems containing HS-C are discussed and specific space applications for HS-C are presented. Equilibrium data for 10 compounds which are found as trace contaminants in closed environments are also presented.
Davis, S. H.↗
Dispersion of heat and humidity from atmospheric spray-cooling systems
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Weinstein, H.↗
Relationships among fractional cloud coverage, relative humidity and condensation in a simple wave model
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Roads, J. O.↗
Physiologic reactions during five weeks of continuous residence in an artificial humid and hot climate
During 5 weeks in a climatic room, total sweat during work almost doubled. Initial hour differences increasingly equalized. There was a displacement of sweat secretion from trunk to extremities till the end of week 3, occurring earlier and more clearly for the arm than for the leg. Work temperatures dropped rapidly and evenly to a constant level by day 11. Circulation behavior matched that of temperature. Pulse rate during work dropped like rectal temperature and pulse rate during rest was phasically like the pattern of corresponding temperatures. Except for the first days urine output was adequate and even, Na decreasing in the urine until week 3, then returning to initial values. Na and K in sweat declined but with opposite patterns for hours 1-4. Total salt elimination decreased. The conclusive phenomena of redistribution occurred within the first 3 weeks. A few functions changed later also. Relatively trivial changes in an otherwise uniform reaction pattern indicated that after 3 or even 5 weeks of acclimatization the process is not over or at least not completely so. The tempo of the process appears to be a function of the degree of loading.
Laaser, U.↗
Apparatus for supplying conditioned air at a substantially constant temperature and humidity
The apparatus includes a supply duct coupled to a source of supply air for carrying the supply air therethrough. A return duct is coupled to the supply duct for carrying return conditioned air therethrough. A temperature reducing device is coupled to the supply duct for decreasing the temperature of the supply and return conditioned air. A by-pass duct is coupled to the supply duct for selectively directing portions of the supply and return conditioned air around the temperature reducing device. Another by-pass duct is coupled to the return duct for selectively directing portions of the return conditioned air around the supply duct and the temperature reduction device. Controller devices selectively control the flow and amount of mixing of the supply and return conditioned air.
Obler, H. D.↗
The relative humidity of Mars' atmosphere
As a general rule, Mars' atmosphere contains as much water vapor as it can hold on a daily basis; it reaches saturation at night, and the vapor appears to be distributed throughout the lowest several kilometers. Interesting exceptions to this occur when there are temperature inversions in the arctic springtime and during dust-storm activity. As contrasted to the northern hemisphere there appears to be no local source of water in the southern temperate and arctic areas.
Davies, D. W.↗
Ozone, dust, smoke and humidity in nuclear winter
Recent correspondence on nuclear winter is commented on. Reasons are given for why the Tunguska meteor explosion may not be useful in calibrating the effects of a major nuclear exchange. The relationship between the optical depth of an aerosol cloud, the composition of the cloud, and its effect on sunlight intensity and climate are clarified. The significance of the Tambora eruption of 1815 and of historical fires for the nuclear winter theory are briefly discussed. The dispersion of smoke plumes from large fires is addressed, and water condensation and smoke scavenging are considered.
Turco, R. P.↗
Studies of humid continental haze during SPACE
A concept for a solar radiometer network to provide supporting data during the Satellite Preciptiation and Cloud Experiment (SPACE) was developed. Each of the 9 prime and 10 supplementary SPACE ground sites will be equipped with an upward pointing global solar pyranometer. About half of the sites will also be equipped with upward pointing diffuse (shade ring) solar pyranometers, and a downward pointing global albedo pyranometer. These radiometers will be used to monitor the spatial and temporal variability of solar insolation and haze optical depth. The insolation data will ultimately be input to numerical models of the pre-storm and near-storm boundary layer. The optical depth data will be compared with simultaneous measurements from airborne and satellite-based passive visible radiometers and airborne lidars.
Bowdle, D. A.↗
Sensitivity of a mesoscale model to initial specification of relative humidity, liquid water and vertical motion
The influence of synoptic scale initial conditions on the accuracy of mesoscale precipitation modeling is investigated. Attention is focused on the relative importance of the water vapor, cloud water, rain water, and vertical motion, with the analysis carried out using the Limited Area Mesoscale Prediction System (LAMPS). The fully moist primitive equation model has 15 levels and a terrain-following sigma coordinate system. A K-theory approach was implemented to model the planetary boundary layer. A total of 15 sensitivity simulations were run to investigate the effects of the synoptic initial conditions of the four atmospheric variables. The absence of synoptic cloud and rain water amounts in the initialization caused a 2 hr delay in the onset of precipitation. The delay was increased if synoptic-scale vertical motion was used instead of mesoscale values. Both the delays and a choice of a smoothed moisture field resulted in underestimations of the total rainfall.
Kalb, M. W.↗
Advancements in oxygen generation and humidity control by water vapor electrolysis
Regenerative processes for the revitalization of manned spacecraft atmospheres or other manned habitats are essential for realization of long-term space missions. These processes include oxygen generation through water electrolysis. One promising technique of water electrolysis is the direct conversion of the water vapor contained in the cabin air to oxygen. This technique is the subject of the present program on water vapor electrolysis development. The objectives were to incorporate technology improvements developed under other similar electrochemical programs and add new ones; design and fabricate a mutli-cell electrochemical module and a testing facility; and demonstrate through testing the improvements. Each aspect of the water vapor electrolysis cell was reviewed. The materials of construction and sizing of each element were investigated analytically and sometime experimentally. In addition, operational considerations such as temperature control in response to inlet conditions were investigated. Three specific quantitative goals were established.
Heppner, D. B.↗