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At least 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Effect of stratified inequality of blood flow on gas exchange in liquid-filled lungs.

This investigation set out to answer two questions: (1) are the distal alveoli in the terminal lung units less well perfused than the proximal alveoli, i.e., is there stratification of blood flow; and (2) if so, does this enhance gas exchange in the presence of stratified inequality of ventilation. Excised dog lungs were ventilated with saline and perfused with blood. Following single inspirations of xenon 133 in saline and various periods of breath holding, the expired xenon concentration against volume was measured and it confirmed marked stratified inequality of ventilation under these conditions. By measuring the rate of depletion of xenon from alveoli during a period of blood flow, we showed that the alveoli which emptied at the end of expiration had 16% less blood flow than those exhaling earlier. However, by measuring the xenon concentration in pulmonary venous blood, we found that about 10% less tracer was transferred from the alveoli into the blood when the inspired xenon was stratified within the respiratory zone. Thus while stratification of blood flow was confirmed, it was shown to impair rather than enhance the efficiency of gas transfer.

West, J. B.↗
NASA NTRS1972

An observation of the Gulf Stream surface front structure by ship, aircraft, and satellite.

Evaluation of observations of surface temperature and salinity along the western edge of the Gulf Stream made from a ship and of concurrent temperature observations obtained by instrumented aircraft at six altitudes. The major feature along a five-kilometer line normal to the Stream's edge is a temperature gradient of about 0.75 C/kilometer within which are embedded two abrupt temperature increases of about 1.5 C. Temperature variations were compensated by salinity variations, yielding nearly constant density through the frontal zone; a sharp lateral current shear was associated with the thermohaline mixing region between the steps. The attenuation of surface temperature measured by the airborne radiometer was compared with a theoretical model. The analysis supports the view that a two-part correction technique is required: one part for bulk-skin temperature differences, and another for atmospheric attenuation of sea surface emission due to the mass and temperature of interfering gases.

Maul, G. A.↗
NASA NTRS1972

Wetlands ecology

The author has identified the following significant results. The ERTS imagery analyzed provides approximately 2/3 coverage of the test site. Analysis was made using visual methods, density slicing, and multispectral analysis. Preliminary conclusions reached are that most, if not all, of the investigation objectives can be met. Saline and near-saline wetlands can be delineated from ERTS-1 images as the wetland-upland boundaries and land-water interface are clearly defined. Major plant species or communities such as Spartina alterniflora (high and low vigor forms), Spartina patens/Distichlis spicata, and Juncus roemarianus can be discriminated and spoil disposal areas identified.

Anderson, R. R.↗
NASA NTRS1972

Sea, ice and surface water circulation, Alaskan Continental Shelf

The author has identified the following significant results. Two cruises were conducted in Cook Inlet to obtain ground truth. Forty-seven stations during 22-23 August and 68 stations during 25-29 September 1972 were occupied and temperature, salinity, percent light transmission, and suspended load of surface waters obtained. Similar data at various depths was also obtained at selected stations. Cook Inlet is an estuary with complex mixing of river discharges and ocean water. The Upper Cook Inlet shows a gradual and systematic decrease in salinity, however, west of Kenai the mixing of waters is complex. The sediments in suspension originating at the head of the inlet generally settle out east of Kenai and Drift River. Sediment load in suspension decreased gradually from 1700 mg/1 near Anchorage to about 50 mg/1 in the Narrows. In the Lower Cook Inlet the suspended load varied between 1-10 mg/1. Surface waters with sediments in suspension and ocean water with relatively lower sediment concentration are clearly discernible in ERTS-1 images obtained during September 18, 1972 pass over Cook Inlet. The movement and mixing of these waters can also be delineated in the images.

Wright, F. F.↗
NASA NTRS1973

A summary of selected early results from the ERTS-1 menhaden experiment

The author has identified the following significant results. Imagery from ERTS-1 satellite was used in conjunction with aerial photographically-sensed menhaden distribution information, sea truth oceanographic measurements, and commercial fishing information from a 8685 square kilometer study area in the north-central portion of the Gulf of Mexico to demonstrate relationships between selected oceanographic parameters and menhaden distribution, ERTS-1 imagery and menhaden distribution, and ERTS-1 imagery and oceanographic parameters. ERTS-1, MSS band 5 imagery density levels correlated with photographically detected menhaden distribution patterns and could be explained based on sea truth Secchi disc transparency and water depth measurements. These two parameters, together with surface salinity, Forel-Ule color, and chlorophyll-a also were found to correlate significantly with menhaden distribution. Eight empirical models were developed which provided menhaden distribution predictions for the study area on combinations of Secchi disc transparency, water depth, surface salinity, and Forel-Ule color measurements.

Stevenson, W. H.↗
NASA NTRS1973

Study of the marine environment of the northern Gulf of California

The author has identified the following significant results. While occupying standard oceanographic stations in the delta region of the Colorado River, two species of insects were collected which were of special interest. One of these is a single specimen of corixid bug, hitherto familiar to the investigators only as a freshwater insect, but taken swimming actively in high salinity water along with characteristic marine plankton. Further investigation showed that the species taken is well known from saline ponds but this is apparently the first record of its occurrence in a complete marine community. A small note on this collection record was prepared for publication and sent in manuscript form to NASA. The other record is of three specimens of a cicindelid beetle (normally a beach inhabitant) found at a night light for larval fish collection on station in the Colorado delta. The beetles were observed to light on and take off from water surface while actively moving around the night light. There is an interesting question of whether this species (Cicindela sinaloae schrammeli Cazier) may be especially adapted for a predatory life on the surface film, while the other two (larger) species sympatric with it are restricted to hunting on land.

Hendrickson, J. R.↗
NASA NTRS1974

Applications of ERTS data to coastal wetland ecology with special reference to plant community mapping and typing and impact of man

Complete seasonal ERTS-1 coverage of Atlantic coastal wetlands from Delaware Bay to Georgia provides a basis for assessment of temporal data for wetland mapping, evaluation, and monitoring. Both MSS imagery and digital data have proved useful for gross wetland species delineation and determination of the upper wetland boundary. Tidal effects and (band to band or seasonal) spectral reflectance differences make it possible to type vegetatively coastal wetlands in salinity related categories. Management areas, spoil disposal sites, drainage ditches, lagoon-type developments and highway construction can be detected indicating a monitoring potential for the future. A northern test site (Maryland-Virginia) and a southern test site (Georgia-South Carolina), representing a range of coastal marshes from saline to fresh, were chosen for intensive study. Wetland maps were produced at various scales using both ERTS imagery (bands 5 and 7) and digital data (bands 4, 5 and 7).

Anderson, R. R.↗
NASA NTRS1975

Monitoring physical and chemical parameters of Delaware Bay waters with an ERTS-1 data collection platform

The author has identified the following significant results. Results of the analysis of data collected during the summer of 1974 demonstrate that the ERTS Data Collection Platform (DCP) is quite responsive to changing water parameters and that this information can be successfully transmitted under all weather conditions. The monitoring of on-site probe outputs reveals a rapid response to changing water temperature, salinity, and turbidity conditions on incoming tides as the tidal salt wedge passes the probe location. The changes in water properties were corroborated by simultaneously sampling the water for subsequent laboratory analysis. Fluctuations observed in the values of salinity, conductivity, temperature and water depth over short time intervals were extremely small. Due to the nature of the probe, 10% to 20% fluctuations were observed in the turbidity values. The use of the average of the values observed during an overpass provided acceptable results. Good quality data was obtained from the satellite on each overpass regardless of weather conditions. Continued use of the DCP will help provide an indication of the accuracy of the probes and transmission system during long term use.

Klemas, V.↗
NASA NTRS1974

Phase 0 study for a geothermal superheated water proof of concept facility

A Phase 0 study for the selection of a representative liquid-dominated geothermal resource of moderate salinity and temperature is discussed. Selection and conceptual design of a nominal 10-MWe energy conversion system, and implementation planning for Phase 1: subsystem (component, experiments) and Phase 2: final design, construction, and operation of experimental research facilities are reported. The objective of the overall program is to demonstrate the technical and economic viability of utilizing moderate temperature and salinity liquid-dominated resources with acceptable environmental impact, and thus encourage commercial scale development of geothermal electrical power generation.

Douglass, R. H.↗
NASA NTRS1975

Hydrogeological investigations in the Pampa of Argentina

In large areas of the Argentinian Pampa the salinization of ground water creates water supply difficulties. Investigations of satellite imagery (Landsat-1 and Skylab) which were based on an extensive ground survey revealed that differences in the vegetation cover are closely related to depth and salinity of ground water. Narrow elongated depressions called bajos are often the only indication of fresh ground water. They can be easily detected on the imagery. Due to their high resolution, Skylab photos even allow a quantitative estimation of fresh ground water situated below the bajos. In general however Landsat-1 imagery sufficed for evaluation. In the area of the Rio Tercero a fossil drainage pattern was discovered and in Corrientes province, soil types could be discriminated and compared to the Soil Map of the World.

Kruck, W.↗
NASA NTRS1975

Remote sensing inputs to water demand modeling

In an attempt to determine the ability of remote sensing techniques to economically generate data required by water demand models, the Geography Remote Sensing Unit, in conjunction with the Kern County Water Agency of California, developed an analysis model. As a result it was determined that agricultural cropland inventories utilizing both high altitude photography and LANDSAT imagery can be conducted cost effectively. In addition, by using average irrigation application rates in conjunction with cropland data, estimates of agricultural water demand can be generated. However, more accurate estimates are possible if crop type, acreage, and crop specific application rates are employed. An analysis of the effect of saline-alkali soils on water demand in the study area is also examined. Finally, reference is made to the detection and delineation of water tables that are perched near the surface by semi-permeable clay layers. Soil salinity prediction, automated crop identification on a by-field basis, and a potential input to the determination of zones of equal benefit taxation are briefly touched upon.

Estes, J. E.↗
NASA NTRS1976

Behavioral fever in newborn rabbits

New Zealand white rabbit pups aged 12 to 72 hr were divided into three groups and given an intraperitoneal injection of Pseudomonas polysaccharide, a saline vehicle alone, and no treatment, respectively. The animals injected with pyrogen and maintained at an ambient temperature of 32 C for 2 hr did not develop fever. When placed in a thermally graded alleyway, the animals injected with pyrogen selected gradient positions that represented significantly higher temperatures than controls injected with saline. Further stay at selected positions for 5 min caused a considerable increase in the rectal temperature of the pyrogen-injected pups but not that of controls. The results support the hypothesis that newborn rabbits will develop a fever by behavioral means after a single injection of an exogenous pyrogen if the opportunity for thermoregulatory behavior is present. No fever develops if the pups must rely solely on internal thermoregulatory mechanisms. The behavioral system for producing a fever is mature at birth, but an adequate system of internal reflexes does not appear to develop for some days.

Satinoff, E.↗
NASA NTRS1977

Groundwater studies in arid areas in Egypt using LANDSAT satellite images

Various features are interpreted which have strong bearing on groundwater in the arid environment. These include the nature of geological and lithologic units, structural lineaments, present and old drainage systems, distribution and form of water pools, geomorphologic units, weathering surfaces and other weathering phenomena, desert soils, sand dunes and dune sand accumulations, growths of natural vegetation and agriculture, and salt crusts and other expressions of salinization. There are many impressive examples which illustrate the significance of satellite image interpretation on the regional conditions of groundwater which could be traced and interconnected over several tens or even several hundreds of kilometers. This is especially true in the northern Western Desert of Egypt where ground water issuing from deep strata comes to the surface along ENE-WSW and ESE-WNW fault lines and fracture systems. Another striking example is illustrated by the occurrence of fresh to brackish groundwater on the Mediterranean Sea Coastal Zone of the Western Desert where the groundwater is found in the form of lenses floating on the saline sea water.

Elshazly, E. M.↗
NASA NTRS1979

Remote sensing analysis of water quality and the entrapment zone in the San Francisco Bay and delta

The author has identified the following significant results. Data from an ocean color scanner flown on a U-2 aircraft at 65,000 ft and from LANDSAT MSS were enhanced to identify biologically active areas of San Francisco Bay, and to determine the salinity, turbidity, chlorophylls, and suspended solids. The best fit regression models for mapping water quality parameters were based on bands 3, 5, 7, and 10. Comparision of the results indicate that chlorophyll concentrations can best be estimated by the OCS or MSS data. Salinity can best be estimated by OCS data; turbidity can best be estimated by LANDSAT data. Neither OCS nor MSS data provide reliable basis for estimating suspended solids. Aerial photography of the highest quality taken with either conventional color or infrared-sensitive color films was unable to locate the biologically active areas.

Colwell, R. N.↗
NASA NTRS1981

Oceanographic influences on the sea ice cover in the Sea of Okhotsk

Sea ice conditions in the Sea of Okhotsk, as determined by satellite images from the electrically scanning microwave radiometer on board Nimbus 5, were analyzed in conjunction with the known oceanography. In particular, the sea ice coverage was compared with the bottom bathymetry and the surface currents, water temperatures, and salinity. It is found that ice forms first in cold, shallow, low salinity waters. Once formed, the ice seems to drift in a direction approximating the Okhotsk-Kuril current system. Two basic patterns of ice edge positioning which persist for significant periods were identified as a rectangular structure and a wedge structure. Each of these is strongly correlated with the bathymetry of the region and with the known current system, suggesting that convective depth and ocean currents play an important role in determining ice patterns.

Gratz, A. J.↗
NASA NTRS1980

Passive microwave sensing of coastal area waters

A technique to remotely measure sea-surface temperature and salinity was demonstrated during the 1970's with a dual-frequency microwave radiometer system developed at the NASA Langley Research Center. Accuracies in temperature of 1 C and 1 part per thousand in salinity were obtained using state-of-the-art radiometers. Several aircraft programs for the measurement of coastal area waters demonstrating the application of the microwave radiometer system are discussed. Improvements of the microwave radiometer system during the 1980's and the design and development of new radiometer systems at other frequencies are outlined and related to potential applications.

Kendall, B. M.↗
NASA NTRS1981

Multifrequency radiometer detection of submarine freshwater sources along the Puerto Rican coastline

The surface area above submarine springs of fresh water exhibit temperatures and salinities lower than the surrounding sea waters. A multifrequency radiometer system which earlier demonstrated an accuracy of 1 degree C and 1 part per thousand in remotely detecting the surface temperature and salinities, respectively, was used to detect submarine freshwater springs. The first mission on February 4, 1978, consisted of overflight measurements over three fourths of the coastal areas around the Island of Puerto Rico. During the second mission on February 6, 1978, special attention was directed to the northwest portion of Puerto Rico where several submarine springs had been reported. The previously reported spring locations correlated well with the locations detected by the radiometers. After separating the surface runoffs such as rivers, lagoons, marshes, and bays, 44 submarine freshwater springs were identified which indicates that the submarine freshwater outflow locations are more numerous around the island than had earlier been estimated. The majority of the submarine springs are located at the northwest and southeast portion of the Puerto Rican coastline. The success of detecting the same submarine springs during both missions at the northwest portion of the island was 39%.

Blume, H.-J. C.↗
NASA NTRS1995

Review of North Atlantic Source Waters

North Atlantic Deep Water (NADW) ventilates the deep World Ocean. It not only carries relatively well-oxygenated waters, but also other substances derived from recent sea-surface exchanges. There are five regional sources for NADW: (1) derivatives of the salty Mediterranean Sea outflow, (2) products of open-ocean convection in the Labrador Sea, (3) Iceland-Scotland Overflow Water from the Norwegian Sea - salty by virtue of mixing with saline water near the sills, (4) Denmark Strait Overflow Water from the Iceland and Greenland Seas - which retains a high-density, relatively low-salinity signal, and (5) remnants of deep water from the Antarctic circumpolar region - freshest of the bottom waters. Despite the differences of characteristics of the source waters, the NADW is relatively uniform. Because the formation of each of the five source waters may be viewed as a response to a complex series of events, it is difficult to examine the sensitivity of NADW to environmental fluctuations. It is known that the deep northern North Atlantic is relatively closely coupled to the sea surface in the Greenland and Iceland seas. The most recent studies indicate a minimum response time of only two years between the introduction of a passive signal north of Iceland and its appearance in the deep northwest Atlantic.

James H Swift↗