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At least 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
NASA NTRS1979

The aerial relay system - An energy-efficient solution to the airport congestion problem

The aerial relay system concept, which was developed as a means of exploiting inflight transfer, utilizing large 'cruise liner' aircraft that fly continuously along their routes and dock periodically with short-haul 'feeder' aircraft for payload exchanges, is discussed. The system employs two distinctly different kinds of aircraft, one for takeoff and landing and one for cruising, with provisions for the routine inflight transfer of passengers, baggage, fuel, etc. The liner design consists of a module of 320 ft span and 80 ft chord with an 800 seat capacity and capable of cruising at 0.75 M, while the feeder is a relatively conventional short-haul transport aircraft with a modified fuselage to accommodate special docking and transportation operations. It is concluded that this concept could alleviate present inadequacies in an extremely cost-effective and fuel-efficient way, and could be expanded indefinitely to become a high-quality, high-capacity national system.

Kyser, A. C.↗
NASA NTRS1979

Possible methods for distinguishing icebergs from ships by aerial remote sensing

The simplest methods for aerial remote sensing which are least affected by atmospheric opacities are summarized. Radar is preferred for targets off the flight path, and microwave radiometry for targets along the flight path. Radar methods are classified by ability to resolve targets. Techniques which do not require target resolution are preferred. Among these techniques, polarization methods appear most promising, specifically those which differentiate the expected relatively greater depolarization by icebergs from that by ships or which detect doubly-reversed circular polarization.

Howes, W. L.↗
NASA NTRS1980

The aerial relay system: An energy-efficient solution to the airport congestion problem

The ability to transfer airline passengers between aircraft in flight, if adequately developed and integrated into the national air transportation system, could provide significant improvements in transportation-system performance, in terms of airport congestion, fuel consumption, and passenger service. The proposed Aerial Relay System concept, which was developed as a means of exploiting inflight transfer, makes use of large 'cruise liner' aircraft which fly continuously along their routes, docking periodically with short-haul feeder aircraft for exchange of payloads. Preliminary vehicle designs for a representative system are described and the operational feasibility of the concept for the United States in the 1990's is discussed.

Kyser, A. C.↗
NASA NTRS1980

Aerial applications dispersal systems control requirements study

Performance deficiencies in aerial liquid and dry dispersal systems are identified. Five control system concepts are explored: (1) end of field on/off control; (2) manual control of particle size and application rate from the aircraft; (3) manual control of deposit rate on the field; (4) automatic alarm and shut-off control; and (5) fully automatic control. Operational aspects of the concepts and specifications for improved control configurations are discussed in detail. A research plan to provide the technology needed to develop the proposed improvements is presented along with a flight program to verify the benefits achieved.

Bauchspies, J. S.↗
NASA NTRS1980

Development of test methods for scale model simulation of aerial applications in the NASA Langley Vortex Facility

Methods have been developed at the Langley Vortex Research Facility to simulate and measure the deposition patterns of aerially applied sprays and granular materials by means of tests with small-scale models of agricultural and dynamically scaled test particles. Interactions between the aircraft wake and the dispersed particles are studied with the aim of modifying wake characteristics and dispersal techniques in order to increase swath width, improve deposition pattern uniformity, and minimize drift. This paper examines the particle sizing analysis, test methods for particle dispersal from the model aircraft, and measurement and computer analysis of test deposition patterns. Results that indicate improved control of chemical drift by winglets are presented to demonstrate test methods.

Jordan, F. L., Jr.↗
NASA NTRS1980

Scaling wake-particle interactions for aerial applications research

The differential equation for the trajectory of a spherical particle injected into an aircraft wake was developed and the proper scaling relations extracted. After some simplification a convenient set of similarity parameters was established. Using these similarity parameters a scale model test program was designed and performed in the NASA Langley vortex research facility. The results of the tests demonstrated the validity of the similarity parameters in conducting scale model testing for aerial application research.

Ormsbee, A. I.↗
NASA NTRS1980

Using 70-mm aerial photography to identify rangeland sites

A south Texas rangeland area was used as a study site to test the use of microdensitometry on 70-mm color-infrared and black-and-white photographs (scale 1:19,000) for distinguishing among 11 range sites (two brushland, seven grassland, two barren land) during the winter (February), spring (May), and summer (August) of 1976. Color-infrared photographs were also taken at a scale of 1:42,000 for the summer date. Film optical density readings were made on one color-infrared film with white light only. The best separations among density readings for all range sites were obtained using white light exposed on color-infrared film in the summer when vegetation was at peak foliage development. Results from this study indicate that 70-mm aerial color-infrared photography at a scale of 1:19,000 or 1:42,000 has good potential for identifying range sites in large and inaccessible areas, and could be a useful tool for range management.

Everitt, J. H.↗
NASA NTRS1982

Aerial Infrared Photos for Citrus Growers

Handbook advises on benefits and methods of aerial photography with color infrared film. Interpretation of photographs is discussed in detail. Necessary equipment for interpretation is described--light table, magnifying lenses, and microfiche viewers, for example. Advice is given on rating tree condition; identifying effects of diseases, insects, and nematodes; and evaluating effects of soil, water, and weather.

Blazquez, C. H.↗
NASA NTRS1980

A scheduling model for the aerial relay system

The ability of the Aerial Relay System to handle the U.S. transcontinental large hub passenger flow was analyzed with a flexible, interactive computer model. The model incorporated city pair time of day demand and a demand allocation function which assigned passengers to their preferred flights.

Ausrotas, R. A.↗
NASA NTRS1980

Theoretical study of network design methodologies for the aerial relay system

The aerial relay system network design problem is discussed. A generalized branch and bound based algorithm is developed which can consider a variety of optimization criteria, such as minimum passenger travel time and minimum liner and feeder operating costs. The algorithm, although efficient, is basically useful for small size networks, due to its nature of exponentially increasing computation time with the number of variables.

Rivera, J. M.↗
NASA NTRS1981

Wetland mapping from digitized aerial photography

Computer assisted interpretation of small scale aerial imagery was found to be a cost effective and accurate method of mapping complex vegetation patterns if high resolution information is desired. This type of technique is suited for problems such as monitoring changes in species composition due to environmental factors and is a feasible method of monitoring and mapping large areas of wetlands. The technique has the added advantage of being in a computer compatible form which can be transformed into any georeference system of interest.

Scarpace, F. L.↗
NASA NTRS1980

Spectral properties of agricultural crops and soils measured from space, aerial, field and laboratory sensors

It is pointed out that in order to develop the full potential of multispectral measurements acquired from satellite or aircraft sensors to monitor, map, and inventory agricultural resources, increased knowledge and understanding of the spectral properties of crops and soils are needed. The present state of knowledge is reviewed, emphasizing current investigations of the multispectral reflectance characteristics of crops and soils as measured from laboratory, field, aerial, and satellite sensor systems. The relationships of important biological and physical characteristics to their spectral properties of crops and soils are discussed. Future research needs are also indicated.

Bauer, M. E.↗
NASA NTRS1981

Microdensitometry to identify saline rangelands on 70-mm color-infrared aerial film

Many of the world's rangelands are affected by salinity. The detection of these areas is important to range and resource managers who are concerned with productivity, condition, and animal carrying capacity. The reported study was conducted along a north-to-south flight line 24 km long and 1.6 wide in Starr County, TX. Everitt et al. (1977) described seven different native range sites (four nonsaline and three saline) along this flight line. The study showed that photointerpretation by microdensitometry could be used to identify saline range sites quantitatively on CIR (0.50 to 0.90 micrometers) aerial film (scales 1:19,000, 1:42,000, and 1:80,000) exposed in May 1976, June 1976, and June 1979. Microdensitometer readings made on CIR film using white or blue light generally gave the best separation between saline and nonsaline range sites. The differences in microdensitometry readings among saline and nonsaline range sites were caused by less plant cover on the saline sites.

Everitt, J. H.↗
NASA NTRS1981

Quantitative analysis of drainage obtained from aerial photographs and RBV/LANDSAT images

Data obtained from aerial photographs (1:60,000) and LANDSAT return beam vidicon imagery (1:100,000) concerning drainage density, drainage texture, hydrography density, and the average length of channels were compared. Statistical analysis shows that significant differences exist in data from the two sources. The highly drained area lost more information than the less drained area. In addition, it was observed that the loss of information about the number of rivers was higher than that about the length of the channels.

Dejesusparada, N.↗
NASA NTRS1981

Combining LANDSAT MSS, aerial photographs and ground measurements to estimate rangeland productivity

The production of a vegetation map of over 2.2 million acres with detail down to the plant community level, and the production of estimates of rangeland productivity (pounds of usable forage per acre for cattle) for a 500,000 acre subset of area with a design goal for accuracy and precision of + or - 20% at the 80% confidence level, are considered. The data consist of five groups: maps of area, LANDSAT data, digital terrain data, large scale aerial photography, and ground plots. An outline of the data acquisition and data reduction schemes are presented.

Gialdini, M. J.↗
NASA NTRS1981

Detection and damage assessment of citrus tree losses with aerial color infrared photography /ACIR/

Detection and disease damage assessment of citrus tree losses in a Florida citrus grove were made by establishing a registration (grove site location) coordinate system, developing a damage assessment system, and testing sequential aerial color infrared (ACIR) photography at the scale of 1 in. = 333 ft (2.5 cm = 100 m) during the winter, spring, and summer seasons of 1978 and spring of 1979. Spring photography was the easiest to photo interpret, showed the greatest differences between healthy and diseased trees, and had the least shadow and background interference for photo interpretation. Trees showing slight disease damage were detected in ACIR before they were found in ground surveys.

Blazquez, C. H.↗
NASA NTRS1981

Use of aerial photography in determining land use and streamflow relationships on small developing watersheds

Using aerial photographs dating back to 1937, the historical trends of five land use classes (crop, forest, open field, urban and suburban) are determined. The relationships between these and various flow regime parameters are investigated. Annual runoff is found to be 7.5 inches greater now than in the year 1932. It is also found that growing season runoff increased by 3.5 inches during the same period. This increase is approximately equivalent to 160 area inches of excess runoff during the 45-year period of observation. The increase in runoff is found to be positively correlated with the percent basin area in the urban, suburban and open field land use classes. A negative correlation is established with forest and crop land. Although poor correlations are found with high flow, low flow, flow interval and flow date data, it is thought that a more precise quantification of land use or a smaller basin area may possibly have yielded more positive results for streamflow timing data.

Owe, M.↗