The 1981 NASA/ASEE Summer Faculty Fellowship Program: Research reports

Research reports related to spacecraft industry technological advances, requirements, and applications were considered. Some of the topic areas addressed were: (1) Fabrication, evaluation, and use of high performance composites and ceramics, (2) antenna designs, (3) electronics and microcomputer applications and mathematical modeling and programming techniques, (4) design, fabrication, and failure detection methods for structural materials, components, and total systems, and (5) chemical studies of bindary organic mixtures and polymer synthesis. Space environment parameters were also discussed

The 1982 NASA/ASEE Summer Faculty Fellowship Program

A NASA/ASEE Summer Faculty Fellowship Research Program was conducted to further the professional knowledge of qualified engineering and science faculty members, to stimulate an exchange of ideas between participants and NASA, to enrich and refresh the research and teaching activities of participants' institutions, and to contribute to the research objectives of the NASA Centers

Research reports: The 1980 NASA/ASEE Summer Faculty Fellowship Program

The Summer Faculty Fellowship Research Program objectives are: to further the professional knowledge of qualified engineering and science faculty members; to stimulate an exchange of ideas between participants and NASA; to enrich and refresh the research and teaching activities of participants and institutions; and to contribute to the research objectives at the NASA centers. The Faculty Fellows engaged in research projects commensurate with their interests and background and worked in collaboration with a NASA/MSFC colleague

Simulation of the Sedimentology of Sediment Detention Basins

Sediment detention basins are a widely used means of controlling downstream sediment pollution resulting from stripmining and construction activities. A mathematical model for describing the sedimentation characteristics of detention basins has been developed. This model requires as inputs the inflow hydrograph, inflow sediment graph, sediment particle size distribution, detention basin stage-area relationship and detention basin stage-discharge relationship. Based on this information the model routes the water and sediment through the basin. In this routing process the outflow sediment concentration graph, the pattern of sediment deposition in the basin and the sediment trapping efficiency are estimated. Comparison of predicted results with measured sediment basin performance indicates the model accurately represents the sedimentation process in detention basins. This report details the model, illustrates its use in design, explains how to process the model on a digital computer and presents a program listing of the model

Studies of Turbulence in Shallow Sediment Laden Flow With Superimposed Rainfall

The structure of turbulence has been shown to affect the sediment carrying capability of streams. Due to the random nature of turbulence, sediment movement was analyzed as a stochastic process. Starting with the Langevin equation modified for a turbulent medium, a partial differential equation was developed as a mathematical model which describes the change in sediment concentration with time and space for two dimensional open channel flow with isotropic turbulence. The input parameters to the partial differential equation were the particle fall velocity and the turbulent diffusion coefficient. The diffusion coefficient used was the product of the mean square velocity and the Eulerian time scale of turbulence. A 4O ft. recirculating research flume was used for the experimental investigations. The RMS velocity and Eulerian time scale profiles were determined by use of a hot-film anemometer and a random signal correlator. The effect of rainfall on the RMS velocities and time scale profiles was observed. Sediment concentration profiles were measured by withdrawing samples from the flow and were compared with values predicted by the derived mathematical model

Water Quality Impacts of Naturals Riparian Grasses Part 2: Modeling Effects of Channelization on Sediment Trapping

A methodology is developed to determine expected sediment trapping in riparian vegetative filter strips considering channelization of flow. The framework consists of defining the channel network stochastically, with deposition/detachment in each channel being modeled deterministically. The two approaches were then combined to develop a model which could predict expected trapping efficiencies for vegetative filters under known field conditions. The model was then extended to include conditions such as rainfall on the filter so as to make it applicable to generic field situations. Field and laboratory studies were conducted to collect and estimate data to develop and evaluate the model. sediment concentrations were measured for natural vegetative filters located on a slope of 8.7%, subjected to inflows from upslope bare soil plots. Surface elevations were measured for the filter. Flow networks and channel shapes were defined by applying the digital elevation model to the micro-relief data. Actual distributions and standard fitted distributions for channel flows and channel shapes were developed. Model evaluation was done for selected values of Manning\u27s n to give predicted filter trapping efficiencies within 2% of the observed, indicating model validity. Sensitivity analysis was conducted using the general model and the fitted probability distributions

The 1974 NASA-ASEE summer faculty fellowship aeronautics and space research program

Research activities by participants in the fellowship program are documented, and include such topics as: (1) multispectral imagery for detecting southern pine beetle infestations; (2) trajectory optimization techniques for low thrust vehicles; (3) concentration characteristics of a fresnel solar strip reflection concentrator; (4) calaboration and reduction of video camera data; (5) fracture mechanics of Cer-Vit glass-ceramic; (6) space shuttle external propellant tank prelaunch heat transfer; (7) holographic interferometric fringes; and (8) atmospheric wind and stress profiles in a two-dimensional internal boundary layer

Pattern languages in HCI: A critical review

This article presents a critical review of patterns and pattern languages in human-computer interaction (HCI). In recent years, patterns and pattern languages have received considerable attention in HCI for their potential as a means for developing and communicating information and knowledge to support good design. This review examines the background to patterns and pattern languages in HCI, and seeks to locate pattern languages in relation to other approaches to interaction design. The review explores four key issues: What is a pattern? What is a pattern language? How are patterns and pattern languages used? and How are values reflected in the pattern-based approach to design? Following on from the review, a future research agenda is proposed for patterns and pattern languages in HCI

Simulating the Water Requirements and Economic Feasibility of Corn in the Midwest

An evaluation of the economics of supplemental irrigation when using a surface water supply must be site specific in order to account for variations in soil moisture holding capacity, watershed area supplying the runoff, climatic conditions, and proposed irrigation management procedures. With the use of farm specific simulation models to determine grain yields, availability of irrigation water, and economic expenditures involved in irrigation, an economic evaluation of supplemental irrigation can be performed, In the model presented in this report, the Duncan SIMAIZ model is used to predict grain yields using long-term daily weather information. SIMAIZ also determines irrigation water demand for the crop. The Haan Water Yield Model is used to predict flow into a reservoir using the same weather information. By knowing daily water flow into a reservoir and water demand for irrigation, a reservoir size is determined which will supply water at all times for the study period. Simulations are then run by incrementally reducing, by volume, the size of this reservoir, thus limiting the availability of irrigation water, and resulting in reduced irrigated yields. An economic evaluation is performed for each reservoir size. Costs and benefits included are: initial cost of constructing the reservoir, yearly reservoir maintenance cost, yearly irrigation costs of operation, and additional income resulting from the increase in grain yields. After the project life has been assumed, the model determines the capital available for investing in an irrigation system for a given year and reservoir size. By ranking these values, a probability distribution is obtained indicating the probability of making money in any given year. By using the Central Limit Theorem, these results are converted to the probability of making money over the life of the system. A sensitivity analysis examines the sensitivity of capital available for investment in an irrigation system to select input variation. The results indicate that great care should be exercised when assigning values to some inputs, while for others, a reasonable estimate is adequate. This model can be used as a tool for evaluating which irrigation practices, if any, are economically feasible. An example of its use is shown

Hydrology and Sedimentology of Dynamic Rill Networks Volume II: Hydrologic Model for Dynamic Rill Networks

A comprehensive model has been developed for use in modeling the hydrologic response of rill network systems. The model, which is called HYMODRIN, is composed of both a hydrologic runoff component and a hydraulic channel routing component. The hydrologic component of the model uses a Green Ampt infiltration approach linked with a nonlinear reservoir runoff model. The channel routing component of the model is baaed on a finite element solution of the diffusion wave equations. In order to account for backwater effects the model employs a dual level iteration scheme. The model may be used in either a stand alone mode or as part of a comprehensive integrated rill erosion model. In the latter case, the hydrologic data for the rill network and the associated interrill flow areas is provided by a geographic-hydrologic interface model called GHIM. This model accepts data from a digital elevation model and translates it into a form compatible with the hydrologic model. This report contains the theoretical development and operating instructions for both GHIM and HYMODRIN. Computer listings for both programs are provided