Low lift-to-drag aero-assisted orbit transfer vehicles

The results of systems analysis conducted on low life drag ratio (L/D) aero-assisted orbit transfer vehicle (AOTV's) are presented. The objectives for this class of vehicle and formulate technology development plans and funding levels to bring the required technologies to readiness levels, as well as develop a credible decision data base encompassing the entire range of low L/D concepts for use in future NASA Aeroassist Orbit Transfer Vehicles studies. Each candidate low L/D concept, the aerobrake, the lifting brake, and the aeromaneuvering concept could be made to work with technologies achievable by the early 1990's. All concepts require flexible structure with flexible thermal protection system (TPS) to be successfully integrated into the shuttle orbiter for launch, all required improvements in guidance and control to fly the dispersed atmospheres at high altitude, and all concepts had potential to evolve from ground-based to space-based operations

Automatic Classification and Speaker Identification of African Elephant (\u3cem\u3eLoxodonta africana\u3c/em\u3e) Vocalizations

A hidden Markov model (HMM) system is presented for automatically classifying African elephant vocalizations. The development of the system is motivated by successful models from human speech analysis and recognition. Classification features include frequency-shifted Mel-frequency cepstral coefficients (MFCCs) and log energy, spectrally motivated features which are commonly used in human speech processing. Experiments, including vocalization type classification and speaker identification, are performed on vocalizations collected from captive elephants in a naturalistic environment. The system classified vocalizations with accuracies of 94.3% and 82.5% for type classification and speaker identification classification experiments, respectively. Classification accuracy, statistical significance tests on the model parameters, and qualitative analysis support the effectiveness and robustness of this approach for vocalization analysis in nonhuman species

Drift Exposure in Tama County

A few months ago, in making some improvements in the roadbed of the Chicago & Northwestern Railroad, a deep cut was made in a hill about three miles west of the city of Toledo, in Tama county, Iowa, where the following section was exposed

A Buried Peat Bed in Dodge Township, Union County, Iowa

Union County already occupies a notable place in the annals of the Pleistocene geology of our State. Near the towns of Thayer and Afton Junction are exposed the gravel beds which first furnished the basis for the separation of the drift of the pre-Kansan age from that of the Kansan, and for the establishment of the Aftonian interglacial interval The name of this latter age of American geology was taken from the town of Afton which is located not far from the above mentioned gravel exposures, in Union county

The Toledo Lobe of Iowan Drift

The southern margin of the main Iowan drift sheet extends in a sinuous line across the central portion of Tama County. From this border a tongue-shaped lobe, having an average width of about six miles, extends southward for a distance of eight or nine miles reaching one mile below the city of Toledo and within two miles of the Iowa River. This extension I have called the Toledo lobe of Iowan drift