Seasonal changes of littoral transport and beach width and resulting effect on protective structures

The shorelines of Maryland's portion of the Chesapeake Bay exhibit seasonal changes in direction of littoral transport and resulting beach width. Observation and study of this process at selected locations emphasizes the necessity of study for a complete year's seasonal cycle before stating erosion rates of an area to be protected by structures and the cyclincal presence or absence of beaches. Seasonal beach conditions at four selected sites are described along with resulting physical changes to protective structures. Through the use of ERTS-1 multi-spectral photography, it will be possible to make widespread predictions elsewhere in the Bay as a direct aid in protective structure design

Independent Orbiter Assessment (IOA): Assessment of the mechanical actuation subsystem, volume 2

The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA approach features a top-down analysis of the hardware to determine draft failure modes, criticality, and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. The IOA results were then compared to the proposed Post 51-L NASA FMEA/CIL baseline that was available. A resolution of each discrepancy from the comparison was provided through additional analysis as required. These discrepancies were flagged as issues, and recommendations were made based on the FMEA data available at the time. This report documents the results of that comparison for the Orbiter Mechanical Actuation System (MAS) hardware. Specifically, the MAS hardware consists of the following components: Air Data Probe (ADP); Elevon Seal Panel (ESP); External Tank Umbilical (ETU); Ku-Band Deploy (KBD); Payload Bay Doors (PBD); Payload Bay Radiators (PBR); Personnel Hatches (PH); Vent Door Mechanism (VDM); and Startracker Door Mechanism (SDM). Criticality was assigned based upon the severity of the effect for each failure mode. Volume 2 continues the presentation of IOA analysis worksheets and contains the potential critical items list, detailed analysis, and NASA FMEA/CIL to IOA worksheet cross reference and recommendations

Going IT Alone: The Experienced IT Worker as Integrator of Business and IT Domains of Knowledge

Though the need for user participation to successfully develop information systems is a commonly accepted MIS axiom, empirical studies have failed to consistently establish the benefits of user participation. To resolve this paradox, we reconsider the underlying premise that business knowledge must be provided by business workers. Instead, as IT is embedded in the business, IT workers necessarily learn both domains in the act of work, and the integration of the two can be achieved through experienced IT workers. To examine this proposition, we studied a group of IT workers who implemented an IS in forty-seven sites over a two year period. Through learning curve methods and change-point analysis, we find that the IT workers achieved greater success as their experience increased while concurrently user participation activities decreased. These findings, consistent with the main proposition, suggest a new approach to valuing the IT workers’ contributions

Research and investigation of geology, mineral, and water resources of Maryland

The authors have identified the following significant results. Field work in Baltimore County revealed that the signature returns of serpentinitic and nonserpentinitic rocks correlates with the vegetation cover and land use pattern. In Maryland Piedmont, bedrock lithology and structure are enhanced only to the extent that land use is geologically dictated. Two prominent sets of linear features are detected on ERTS-1 imagery at N 45 deg E and N 20 deg E. Beaches of Chesapeake Bay are classified as broad and narrow beaches based on the width of the backshore zone. It is shown by comparing historical shorelines of Ocean City, from the inlet to the Maryland-Delaware line that reversal zones of erosion and accretion occur at different locations for different periods. High reflectance levels (high marsh-high topographic areas) for the lower Eastern Shore are found to be distributed as two distinct trending linear ridge systems. Observations of MSS band 5 dated 9 April 1974 exhibited an unique sedimentation pattern for Chesapeake Bay. Following a 1.5 inch rainfall, heavy concentration of suspended sediments is observed on the imagery, particularly in the area of the turbidity maximum

Geological and Paleontological Survey of the Bardwell Reservoir Basin, Ellis County, Texas

During June, July, and August, 1964, the Shuler Museum of Paleontology of Southern Methodist University made a survey of that portion of Waxahachie Creek that is to be flooded by the construction of the Bardwell Dam. The work was done under the sponsorship of the National Park Service (Southwest Region). The Quaternary deposits of Waxahachie Creek were mapped in detail and the bedrock geology outlined in general units. Extensive prospecting of all erosional and excavational exposures was carried out for the purpose of recovering both Cretaceous and Quaternary vertebrate and molluscan fossils. Two terraces were recognized above the present floodplain; the higher and older of the two contained identifiable remains of a mammoth and an excellent molluscan fauna. Fossils recovered from the Cretaceous bedrock include a fairly complete lower jaw of a marine reptile (mosasaur) and specimens of one teolost and at least six species of elasmobranch fishes. A new genus and species of ganopristid sawfish is also included

Geological and Paleontological Survey of the Forney Reservoir Basin, Kaufman and Rockwall Counties, Texas

The field work for this report was done during June, July, and August, 1964, by the Shuler Museum of Paleontology of Southern Methodist University under National Park Service Contract No. RO 330608. The Quaternary deposits of the East Fork of the Trinity River were mapped in the area of the basin of the proposed Forney Reservoir and the general patterns of bedrock geology outlined. All excavational and erosional exposures of terrace, floodplain, and bedrock deposits were prospected for molluscan and vertebrate fossils. Three terraces above the present floodplain are recognized

A Landslide Climate Indicator from Machine Learning

In order to create a Landslide Hazard Index, we accessed rain, snow, and a dozen other variables from the National Climate Assessment Land Data Assimilation System. These predictors were converted to probabilities of landslide occurrence with XGBoost, a major machine-learning tool. The model was fitted with thousands of historical landslides from the Pacific Northwest Landslide Inventory (PNLI)