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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS2015

Climate Change Impacts on Rice Farming Systems in Northwestern Sri Lanka

Sri Lanka has achieved tremendous progress since 1950 in crop production and food availability. Yields grew at an impressive rate until leveling off in the mid-eighties. Sri Lanka's population is anticipated to grow in the coming decades, creating an ever-greater demand for food security on the household, sub-district, regional, and national scales.The agricultural sector in Sri Lanka is vulnerable to climate shocks. An unusual succession of droughts and floods from 2008 to 2014 has led to both booms and busts in agricultural production, which were reflected in food prices. In both instances, the majority of farmers and consumers were adversely affected.At present the rice-farming systems are under stress due to inadequate returns for the farmers and difficulty in coping with shocks due to climate, pests, and diseases, and prices for produce. There are government price-support mechanisms, fertilizer-subsidy schemes, and crop insurance schemes, but the levels of the supports are modest and often do not effectively reach the farmers.

agriculture↗
NASA NTRS2014

Environmental and Socio-Demographic Determinants of Dengue Fever in Colombo City, Sri Lanka

Dengue fever has increased exponentially in Sri Lanka, from 24.4 cases per 100,000 in 2003 to 165.3 per 100,000 population in 2013. Although early warning systems using predictor models have been previously developed in other settings, it is important to develop such models in each local setting. Further, the ability of these models to be applicable at smaller geographic units will enhance current vector control and disease surveillance measures. The aim of this paper was to identify environmental and socio-economic status (SES) risk factors that may predict dengue fever at the Gram Niladhari Divisions (GND) level (smallest administrative unit) in Colombo city, Sri Lanka. These factors included landcover classes, amount of vegetation, population density, water access and neighborhood SES as determined by roof type. A geographically weighted regression (GWR) was used to develop the prediction model. A total 55 GND units covering an area of 37 sq km were investigated. We found that GND units with decreased vegetation, higher built-up area, higher population density and poor access to tap-water supply were associated with high risk of dengue; the pertinent GND units were concentrated in the center of the city. This is the first study in Sri Lanka to include both environmental and socio-demographic factors in prediction models for dengue fever. The methodology may be useful in enhancing ongoing dengue fever control measures in the country, and to be extended to other countries in the region that have an increasing incidence of dengue fever.

Tipre, Meghan↗
NASA NTRS1973

Lidar Development at SRI - The First Decade

On 22 July 1963 the first lidar observations of the lower atmosphere were made at SRI with a pulsed ruby system developed by a team led by the late Myron G. H. Ligda. Since that time SRI has carried out a continuous program of exploration and development of the technique, primarily related to applications in atmospheric research in the troposphere. In this frankly personal retrospective, some of the highlights of this ten years are reviewed, both in terms of progress made and difficulties experienced. Topics discussed will include the technological aspects of the lidar systems used, the range of applications identified and explored and the various forms of information recovery and display that have been developed.

Collis, R. T. H.↗
NASA NTRS1980

Preliminary analysis of data from SRI international transient pulse monitor on board P78-2 SCATHA satellite

The satellite charging at high altitudes (SCATHA) program addresses the occurrence of electrostatic discharges causing undesirable effects like deleterious transients in electronic circuits on satellites. The high altitude plasma environment and the effects of the interaction of this environment with the orbiting satellite are studied. The SRI transient pulse monitor (TPM) detects the transient electromagnetic signals induced in selected circuits. As a transient detector the TPM records transient signals, indicates the number of transients observed, and gives peak amplitude of the largest transient during each second's interval. Most of the early data from the TPM contain pulses associated with internal electrical activity and electrostatic charging on the surface of the P78-2 is evidenced. It is found that periods of external discharging do not necessarily coincide with periods in which high potentials are measured on the satellite's surface.

Damron, S. A.↗
NASA NTRS1971

Activities of the NASA sponsored SRI technology applications team in transferring aerospace technology to the public sector

The organization and functions of an interdisciplinary team for the application of aerospace generated technology to the solution of discrete technological problems within the public sector are presented. The interdisciplinary group formed at Stanford Research Institute, California is discussed. The functions of the group are to develop and conduct a program not only optimizing the match between public sector technological problems in criminalistics, transportation, and the postal services and potential solutions found in the aerospace data base, but ensuring that appropriate solutions are acutally utilized. The work accomplished during the period from July 1, 1970 to June 30, 1971 is reported.

Berke, J. G.↗
NASA NTRS1973

Use of the SRI electronic satellite image analysis console for mapping southern Arizona plant communities from ERTS-1 imagery

Cloud-free imagery covering the Tucson, Ariz., region for the period from August 22 to November 2, 1972, was used to determine the utility of ERTS-1 data for discriminating boundaries between plant communities. The following studies were made from imagery analyzed by use of an Electronic Satellite Image Analysis Console: (1) console-generated color composites from MSS-5 and MSS-6 bands were recorded photographically from the console color monitor. The color photographs were then used to compare with short-term changes in vegetative cover observed on the ground; (2) using the console, microdensitometric traces were made along selected traverses to quantify changes in scene irradiance across the image field; (3) quantitative plant coverage data, collected at ground-truth stations along the traverses, were compared with the densitometric values.

Turner, R. M.↗
NASA NTRS1976

Investigation of the agricultural resources in Sri Lanka

The author has identified the following significant results. It is observed that LANDSAT data is easily adaptable to photogrammetric techniques. With such adaptations, revision of topographic or thematic maps can be performed at very little cost. Revision of maps up to scale 1:100,000 (or better) can be performed. The LANDSAT image has definite advantages over the standard methods in areas of extensive development where the synoptic view of the LANDSAT image offers the required control in the form of distant mapped data in one frame.

Silva, A. T. M.↗
NASA NTRS1977

Investigation of the agricultural resources in Sri Lanka

The author has identified the following significant results. Several in-house capabilities were developed. The facilities to prepare color composites of excellent quality were developed, using bulk B/W 70 mm transparencies or 1:1,000,000 positive transparencies. These color composites were studied through optical devices on light tables. A zoom transfer scope was also added, enabling direct transfer of LANDSAT composite data on to base maps.

Silva, A. T. M.↗
NASA NTRS1980

Application of the SRI cloud-tracking technique to rapid-scan GOES observations

An automatic cloud tracking system was applied to multilayer clouds associated with severe storms. The method was tested using rapid scan observations of Hurricane Eloise obtained by the GOES satellite on 22 September 1975. Cloud tracking was performed using clustering based either on visible or infrared data. The clusters were tracked using two different techniques. The data of 4 km and 8 km resolution of the automatic system yielded comparable in accuracy and coverage to those obtained by NASA analysts using the Atmospheric and Oceanographic Information Processing System.

Wolf, D. E.↗
NASA NTRS1982

Experiences and perspectives with SRI's tools for software design and validation

Development of tools that include the STP theorem poer and its associated Design Verification Systems; PHIL, a meta-programmable context sensitive structured editor; Pegasus, a system for support of graphical programming; and OBJ, an ultra high level programming language based on rewrite rules and abstract data type is reported.

Goguen, J.↗
NASA NTRS1983

A Formal Semantics for the SRI Hierarchical Program Design Methodology

A formal statement of what it means to use (a subset of) the methodology is presented. It is formally defined that some specified module exists and what it means to say that another module is paid correctly implemented on top of it. No attention is to motivation, either of the methodology or of the formal development of it. Concentration is entirely upon mathematical succinctness and precision. A discussion is presented of how to use certain INTERLISP programs which implement the formal definitions. Among these are a program which generates Floyd like verification conditions sufficient to imply the correctness of a module implementation.

Boyer, R. S.↗