1,919 research outputs found
VOCALIZATION OF THE CROCODILE SKINK, TRIBOLONOTUS GRACILIS (DE ROOY, 1909), AND EVIDENCE OF PARENTAL CARE.
The crocodile or spiny skinks, Tribolonotus, comprise eight secretive semi-fossorial lizards, which are generally found under vegetation in the immediate vicinity of water (Greer and Parker, 1968; O'Shea, 1991, 1994; Rogner, 1997). Tribolonotus gracilis (Figure 1) and Tribolonotus novaeguineae are restricted to New Guinea, while the remaining six species range throughout Indonesia, Manus, New Britain, Bougainville, and the Solomon Islands (McCoy, 1980; O'Shea, 1991, 1994). Because scant life history information is available for the genus Tribolonotus, the purpose of the present contribution is to document the vocalization and parental care of T. gracilis
The Effect of Computer-Generated Instructional Feedback and Videotape on the Speaking Performance of College Students in Basic Speech Course
1992 Award Winning Paper in Basic Course Pedagogy
This study examines the effect of computer-generated feedback and videotapes speech performances on the speech skill improvement of college students. Subjects are evaluated on total speech performance and on: (1) organization; (2) development; (3) style; (4) vocal quality; and (5) gestural quality.
Results indicate: (1) computer-generated feedback appear to be as effective as handwritten feedback; (2) providing instructor feedback before self-analysis of videotaped performances; and (3) providing computer-generated feedback appears to improve subjects\u27 delivery speech skill performance
Fitting EXAFS data using molecular dynamics outputs and a histogram approach
The estimation of metal nanoparticle diameter by analysis of extended x-ray absorption fine structure (EXAFS) data from coordination numbers is nontrivial, particularly for particles <5 nm in diameter, for which the undercoordination of surface atoms becomes an increasingly significant contribution to the average coordination number. These undercoordinated atoms have increased degrees of freedom over those within the core of the particle, which results in an increase in the degree of structural disorder with decreasing particle size. This increase in disorder, however, is not accounted for by the standard means of EXAFS analysis, where each coordination shell is fitted with a single bond length and disorder term. In addition, the surface atoms of nanoparticles have been observed to undergo a greater contraction than those in the core, further increasing the range of bond distances. Failure to account for this structural change results in an increased disorder being measured, and therefore, a lower apparent coordination number and corresponding particle size are found. Here, we employ molecular dynamics (MD) simulations for a range of nanoparticle sizes to determine each of the nearest neighbor bond lengths, which were then binned into a histogram to construct a radial distribution function (RDF). Each bin from the histogram was considered to be a single scattering path and subsequently used in fitting the EXAFS data obtained for a series of carbon-supported platinum nanoparticles. These MD-based fits are compared with those obtained using a standard fitting model using Artemis and the standard model with the inclusion of higher cumulants, which has previously been used to account for the non-Gaussian distribution of neighboring atoms around the absorber. The results from all three fitting methods were converted to particle sizes and compared with those obtained from transmission electron microscopy (TEM) and x-ray diffraction (XRD) measurements. We find that the use of molecular dynamics simulations resulted in an improved fit over both the standard and cumulant models, in terms of both quality of fit and correlation with the known average particle size
Weld repair of directionally solidified articles
A directionally solidified nickel-base superalloy article has a defect therein extending parallel to the solidification direction. The article is repaired by removing any foreign matter present in the defect, and then heating the article to a repair temperature of from about 60 to about 98 percent of the solidus temperature of the base material in a chamber containing a protective gas that inhibits oxidation of the base material. The defect is filled with a filler metal while maintaining the article at the repair temperature. The filling is accomplished by providing a source of the filler metal of substantially the same composition as the base material of the directionally solidified article, and melting the filler metal into the defect progressively while moving the source of the filler metal relative to the article in a direction parallel to the solidification direction. Optionally, additional artificial heat extraction is accomplished in a heat-flow direction that is within about 45 degrees of the solidification direction, as the filler metal solidifies within the defect. The article may thereafter be heat treated
Directionally solidified article with weld repair
A directionally solidified nickel-base superalloy article has a defect therein extending parallel to the solidification direction. The article is repaired by removing any foreign matter present in the defect, and then heating the article to a repair temperature of from about 60 to about 98 percent of the solidus temperature of the base material in a chamber containing a protective gas that inhibits oxidation of the base material. The defect is filled with a filler metal while maintaining the article at the repair temperature. The filling is accomplished by providing a source of the filler metal of substantially the same composition as the base material of the directionally solidified article, and melting the filler metal into the defect progressively while moving the source of the filler metal relative to the article in a direction parallel to the solidification direction. Optionally, additional artificial heat extraction is accomplished in a heat-flow direction that is within about 45 degrees of the solidification direction, as the filler metal solidifies within the defect. The article may thereafter be heat treated
PRESTRESS LOSSES AND THE ESTIMATION OF LONG-TERM DEFLECTIONS AND CAMBER FOR PRESTRESSED CONCRETE BRIDGES (FHWA-OK-07-08)
Prestressed concrete, an ideal combination of concrete and high strength steel, has emerged as an efficient material for modern construction. The construction of prestressed concrete bridges as a standard practice in the United States dates back to 1949 when the Philadelphia Walnut Ave Bridge was constructed. The technical and economical benefits of prestressed concrete permits longer spans and increased girder spacing. Complimenting this, higher performance concrete can feature lower water to cementious materials ratio (w/cm) and the inclusion of supplemental cementious materials that promote a dramatic improvement of concrete quality and durability.Final reportN
Epidemiology and Control of a Head Louse Outbreak in Ames, Iowa, 1976
At the onset of school in 1976, head lice were recognized by teachers and school nurses in the public and parochial schools in Ames, Iowa. One or more cases were identified from the 9 elementary schools and 3 secondary schools in the community. The greatest prevalence of louse infestations occurred in 2 elementary schools (1 parochial) where 16% and 14%, respectively, of the students were infested. A program was established to screen children and exclude infested individuals from class until they were effectively treated. The community was surveyed to determine the extent of infestation in each household from which at least 1 member was attending school and had a confirmed louse infestation. Data were tabulated on the incidence of louse infestations by school, grade, sex, hair color, hair length, number of persons living in homes where louse infestations were recognized and incomes of families that had infested members. Factors that contributed to louse transmission and an evaluation of an intensive community-wide control program are discussed
Method for welding an article and terminating the weldment within the perimeter of the article
An article is welded, as in weld repair of a defect, by positioning a weld lift-off block at a location on the surface of the article adjacent to the intended location of the end of the weldment on the surface of the article. The weld lift-off block has a wedge shape including a base contacting the surface of the article, and an upper face angled upwardly from the base from a base leading edge. A weld pool is formed on the surface of the article by directly heating the surface of the article using a heat source. The heat source is moved relative to the surface of the article and onto the upper surface of the weld lift-off block by crossing the leading edge of the wedge, without discontinuing the direct heating of the article by the heat source. The heating of the article with the heat source is discontinued only after the heat source is directly heating the upper face of the weld lift-off block, and not the article
Imaging the Disk and Jet of the Classical T Tauri Star AA Tau
Previous studies of the classical T Tauri star AA Tau have interpreted the UX-Orionis-like photo-polarimetric variability as being due to a warp in the inner disk caused by an inclined stellar magnetic dipole field. We test that these effects are macroscopically observable in the inclination and alignment of the disk. We use Hubble Space Telescope (HST)/STIS coronagraphic imagery to measure the V magnitude of the star for both STIS coronagraphic observations, compare these data with optical photometry in the literature, and find that, unlike other classical T Tauri stars observed in the same HST program, the disk is most robustly detected in scattered light at stellar optical minimum light.We measure the outer disk radius, 1 inch.15 plus-minus 0 inch.10, major-axis position angle, and disk inclination and find that the inner disk, as reported in the literature, is both misinclined and misaligned with respect to the outer disk. AA Tau drives a faint jet, detected in both STIS observations and in follow-on Goddard Fabry-Perot imagery, which is also misaligned with respect to the projection of the outer disk minor axis and is poorly collimated near the star, but which can be traced 21 inches from the star in data from 2005. The measured outer disk inclination, 71deg plus-minus 1deg, is out of the range of inclinations suggested for stars with UX-Orionis-like variability when no grain growth has occurred in the disk. The faintness of the disk, small disk size, and detection of the star despite the high inclination all indicate that the dust disk must have experienced grain growth and settling toward the disk midplane, which we verify by comparing the observed disk with model imagery from the literature
INVESTIGATION OF OPTIMIZED GRADED CONCRETE FOR OKLAHOMA - PHASE 2
Optimizing aggregate usage has been a subject widely discussed through the history of concrete. Since aggregates make up over 70% of the volume in a concrete mixture, the aggregate gradation is critical to the strength, workability, and durability of concrete. In practice, there is little quantitative guidance given to practitioners on aggregate proportioning in a mixture to meet the desired performance. The ACI 211 Mixture Design Procedure maybe the most widely taught mixture design method, but still is not widely used in practice due to limitations with the method. In fact, the ACI 211 method only contains a handful of aggregate parameters that many argue about the validity. One of the largest obstacles preventing the development of aggregate parameters and guidance comes from only a few test methods that are capable of providing quantitative data about the workability of concrete. This work focused on creating practical test methods and using them to understand how the aggregate gradation changes the workability of concrete.A series of workability tests for concrete were developed/used to investigate mixtures for bridge deck applications. Each test is used to evaluate various aggregate gradations and develop a new set of design recommendations and specifications.The ultimate product of this work is a new specification for the state of Oklahoma for mixtures with a greater durability at reduced cost and with improved sustainability. Based on 2015 production this design method has the potential to save the state of Oklahoma over $1.5 million per year, enough power for 440 Oklahoma homes, and reduce long term costs through reduced maintenance from durability issues.Final report, October 2013-October 2015N
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