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At least 217 records · Page 12

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NASA NTRS1973

Industrial realization of a direct Fourier transform in automated experimental data processing systems

Fourier processing of automatic signals transforms direct current voltage into a numerical form through bandpass filtration in time-pulse multiplying devices. It is shown that the ratio of the interference energy to the useful signal energy is inversely proportional to the square of the product of the depth of the width modulation and the ratio of the time constant averaging to the cross-multiplied signals.

Lyubashevskiy, G. S.↗

NASA NTRS1973

Transmissometry and suspended matter in lower Chesapeake Bay - Correlation with ERTS multispectral imagery

The use of multispectral imagery from the Earth Resources Technology Satellite to quantitatively monitor turbidity and suspended matter of estuarine waters is being evaluated in this study. Synoptic measurements of surface-water characteristics are being made on three baselines in lower Chesapeake Bay in synchrony with satellite overpasses. Turbidity is measured as transmittance by a continuously recording transmissometer, and suspended matter is collected by filtration. Preliminary correlations to ERTS multispectral imagery have been made by microdensitometry. Final correlations will be made from the bulk tape format.

Bowker, D. E.↗

NASA NTRS1974

Renal parameter estimates in unrestrained dogs

A mathematical formulation has been developed to describe the hemodynamic parameters of a conceptualized kidney model. The model was developed by considering regional pressure drops and regional storage capacities within the renal vasculature. Estimation of renal artery compliance, pre- and postglomerular resistance, and glomerular filtration pressure is feasible by considering mean levels and time derivatives of abdominal aortic pressure and renal artery flow. Changes in the smooth muscle tone of the renal vessels induced by exogenous angiotensin amide, acetylcholine, and by the anaesthetic agent halothane were estimated by use of the model. By employing totally implanted telemetry, the technique was applied on unrestrained dogs to measure renal resistive and compliant parameters while the dogs were being subjected to obedience training, to avoidance reaction, and to unrestrained caging.

Rader, R. D.↗

NASA NTRS1975

Improved extraction technique for biological fluids

Liquid-liquid extraction technique speeds up separation of biological fluids into number of compounds. This eliminates agitation, emulsion formation, centrifugation, mechanical separation of phases, filtration, and other steps that have been used previously. Extraction efficiencies are equal or better than current manual liquid-liquid extraction techniques.

Jahnsen, V. J.↗

NASA NTRS1974

Shuttle filter study. Volume 2: Contaminant generation and sensitivity studies

Contaminant generation studies were conducted at the component level using two different methods, radioactive tracer technique and gravimetric analysis test procedure. Both of these were reduced to practice during this program. In the first of these methods, radioactively tagged components typical of those used in spacecraft were studied to determine their contaminant generation characteristics under simulated operating conditions. Because the purpose of the work was: (1) to determine the types and quantities of contaminants generated; and (2) to evaluate improved monitoring and detection schemes, no attempt was made to evaluate or qualify specific components. The components used in this test program were therefore not flight hardware items. Some of them had been used in previous tests; some were obsolete; one was an experimental device. In addition to the component tests, various materials of interest to contaminant and filtration studies were irradiated and evaluated for use as autotracer materials. These included test dusts, plastics, valve seat materials, and bearing cage materials.

Source record↗

NASA NTRS1975

Application of vascular aquatic plants for pollution removal, energy and food production in a biological system

Vascular aquatic plants such as water hyacinths (Eichhornia crassipes) (Mart.) Solms and alligator weeds (Alternanthera philoxeroides) (Mart.) Griesb., when utilized in a controlled biological system (including a regular program of harvesting to achieve maximum growth and pollution removal efficiency), may represent a remarkably efficient and inexpensive filtration and disposal system for toxic materials and sewage released into waters near urban and industrial areas. The harvested and processed plant materials are sources of energy, fertilizer, animal feed, and human food. Such a system has industrial, municipal, and agricultural applications.

Wolverton, B. C.↗

NASA NTRS1975

Renal effects of continuous negative pressure breathing

Continuous negative pressure breathing (CNPB) was utilized to simulate the thoracic vascular distension of zero g or space, in 11 anesthetized rats. The animals underwent renal clearance and micropuncture renal nephron studies before, during, and after CNPB. Rats were pretreated with a high salt diet and I-M desoxycorticosterone (DOCA) in excess. None of these rats diuresed with CNPB. In contrast 5 of the 7 remaining rats increased the fraction of the filtered sodium excreted (C sub Na/GFR, p .05) and their urinary flow rate (V, p .05). Potassium excretion increased (U sub k V, p .05). End proximal tubular fluid specimen's TF/P inulin ratios were unchanged. Whole kidney and single nephron glomerular filtration rates fell 10%. CNPB, a mechanism for atrial distension, appears to cause, in rats, a decrease in distal tubular sodium, water and potassium reabsorption. Exogenous mineral-corticoid prevents the diuresis, saluresis, and kaluresis.

Kinney, M. J.↗

NASA NTRS1974

Water depth penetration film test

As part of the National Aeronautics and Space Administration Earth Resources Program, a comparative and controlled evaluation of nine film-filter combinations was completed to establish the relative effectiveness in recording water subsurface detail if exposed from an aerial platform over a typical water body. The films tested, with one exception, were those which prior was suggested had potential. These included an experimental 2-layer positive color film, a 2-layer (minus blue layer) film, a normal 3-layer color film, a panchromatic black-and-white film, and a black-and-white infrared film. Selective filtration was used with all films.

Lockwood, H. E.↗

NASA NTRS1975

Processing corrections for Skylab photographic imagery

Camera filters were inadvertently omitted from the six-channel multispectral photographic camera (S190A) during the exposure of the first roll of film from each channel on the final manned Skylab mission. Each of the films was overexposed and degraded as a result of the filter omissions. Explained are the techniques used by the NASA/JSC Photographic Technology Division to evaluate and process those films. These or similar techniques can be used in other photographic multispectral remote sensing applications in which black-and-white infrared and panchromatic or color infrared film are degraded due to loss of filtration or to overexposure. Results prove that data may be salvaged after camera exposure errors are made thus saving the expense of reacquiring data.

Lockwood, H. E.↗

NASA NTRS1977

Extraction of urea and ammonium ion

Water purification system keeps urea and ammonium ion concentration below toxic limits in recirculated water of closed loop aquatic habitat. Urea is first converted to ammonium ions and carbon dioxide by enzygmatic action. Ammonium ions are removed by ion exchange. Bioburden is controlled by filtration through 0.45 micron millipore filters.

Anselmi, R. T.↗

NASA NTRS1975

Water Hyacinths for Upgrading Sewage Lagoons to Meet Advanced Wastewater Treatment Standards, Part 1

Water hyacinths, Eichhornia crassipes Mart. Solms, have demonstrated the ability to function as an efficient and inexpensive final filtration system in a secondary domestic sewage lagoon during a three month test period. These plants reduced the suspended solids, biochemical oxygen demanding substances, and other chemical parameters to levels below the standards set by the state pollution control agency. The water hyacinth-covered secondary lagoon utilized in this experiment had a surface area of 0.28 hectare (0.70 acre) with a total capacity of 6.8 million liters (1.5 million gallons), receiving an inflow of 522,100 liters (115,000 gallons) per day from a 1.1 hectare (3.8 acre) aerated primary sewage lagoon. These conditions allowed a retention time of 14 to 21 days depending on the water hyacinth evapotranspiration rates. The desired purity of final sewage effluent can be controlled by the water hyacinth surface area, harvest rate, and the retention time.

Wolverton, B. C.↗

NASA NTRS1975

Renal effects of continuous negative pressure breathing

Continuous negative pressure breathing (CNPB) was utilized to simulate the thoracic vascular distension of zero G in 11 anesthetized rats. The animals underwent renal clearance and micropuncture renal nephron studies before, during, and after CNPB. Four rats were pretreated with a high salt diet and I-M desoxycorticosterone (DOCA) in excess. None of these rats diuresed with CNPB. In contrast, five of the seven remaining rats increased the fraction of the filtered sodium excreted and their urinary flow rate. Potassium excretion increased. End proximal tubular fluid specimen's TF/P inulin ratios were unchanged. Whole kidney and single nephron glomerular filtration rates fell 10%. CNPB, a mechanism for atrial distension, appears to cause in the rat a decrease in distal tubular sodium and water reabsorption. Exogenous mineral-corticoid prevents the diuresis, saluresis, and kaluresis. The adequacy of other nonatrial volume control mechanisms in regulating renal salt and water conservation in opposition to the studied atrial-renal (Henry-Gauer) reflex of thoracic vascular distension is confirmed.

Kinney, M. J.↗

NASA NTRS1976

Don't waste waterweeds

Experiments carried out at the NASA National Space Technology Laboratories indicate that water hyacinths can absorb organic chemicals, heavy metals, nutrients, and other materials from waste water while producing large quantities of biomass, which can be used to produce a gas containing 60-80% methane. When grown in sewage free of toxic materials, the biomass can be used as a potential source of fertilizer or animal feed supplements. The use of hot water from nuclear power plants to grow water hyacinths during the winter months is particularly attractive, since the hyacinths could act as an added safety filtration system for the removal of radioactive elements.

Wolverton, B.↗

NASA NTRS1976

Influence of acoustics in separation processes

The effects of introducing high energy acoustics into various filtering and drying systems were studied. With very slow velocity filtration systems, it was found that the introduction of acoustics could substantially increase the flow rate and also aided in the coagulation of the particulates before reaching the filter media. In the drying of temperature sensitive powders, the rate was increased by the introduction of acoustics. The acoustic frequency used was 20 kHz with power levels up to 3 watts per square centimeter.

Fairbanks, H. V.↗

NASA NTRS1976

Hollow fiber membrane systems for advanced life support systems

The practicability of utilizing hollow fiber membranes in vehicular and portable life support system applications is described. A preliminary screening of potential advanced life support applications resulted in the selection of five applications for feasibility study and testing. As a result of the feasibility study and testing, three applications, heat rejection, deaeration, and bacteria filtration, were chosen for breadboard development testing; breadboard hardware was manufactured and tested, and the physical properties of the hollow fiber membrane assemblies are characterized.

Roebelen, G. J., Jr.↗

NASA NTRS1977

Wash water waste pretreatment system

Investigations were completed on wash waters based on each candidate personal cleansing agent. Evaluations of coagulants, antifoam agents, and the effect of promising antifoams on the chemical precipitation were included. Based on these evaluations two candidate soaps as well as their companion antifoam agents were selected for further work. Operating parameters included the effect of soap concentration, ferric chloride concentration, duration of mixing, and pore size of depth filters on the degree of soap removal. The effect of pressure on water flow through filter cartridges and on the rate of decline of water flow was also investigated. The culmination of the program was the recommendation of a pretreatment concept based on chemical precipitation followed by pressure filtration.

Source record↗

NASA NTRS1976

Analytical notes - Electrochemical method for early detection and monitoring of coliforms

An electrochemical method for detecting bacteria, based on a linear relationship between inoculum size and the time of hydrogen evolution, was tested for the early detection and monitoring of coliforms in naturally contaminated estuarine and fresh water samples. Standard methods for coliform analysis were performed on each sample, and membrane filtration counts were used to construct dose-response curves; relationships and results are discussed herein.

Wilkins, J. R.↗

NASA NTRS1976

Effects of water immersion on renal hemodynamics in normal man

The present study was undertaken to delineate the effects of water immersion to the neck (NI) on renal plasma flow and glomerular filtration rate as assessed by the clearance of p-aminohippuric acid (PAH) and inulin, respectively. Nine normal male subjects were studied on two occasions, control and NI. The conditions of seated posture and time of day were identical. Immersion did not alter either clearance at a time when sodium excretion was increasing markedly. The constancy of PAH clearance during NI suggests that renal blood flow is unaltered and that the natriuresis of NI is mediated independently of alterations in overall renal perfusion. The sluggish decline of a natriuresis during recovery is consistent with the presence of a humoral factor contributing to the encountered natriuresis.

Epstein, M.↗