Infrared reflectance measurements Final report, 1 Jan. 1967 - 30 Jun. 1969

Design and testing of ellipsoidal mirror reflectometer, and interferometer spectrometer measurement of mirror reflectanc

Nanocrystalline Zr3Al Made through Amorphization by Repeated Cold Rolling and Followed by Crystallization

The intermetallic compound Zr3Al is severely deformed by the method of repeated cold rolling. By X-ray diffraction it is shown that this leads to amorphization. TEM investigations reveal that a homogeneously distributed debris of very small nanocrystals is present in the amorphous matrix that is not resolved by X-ray diffraction. After heating to 773 K, the crystallization of the amorphous structure leads to a fully nanocrystalline structure of small grains (10 - 20 nm in diameter) of the non-equilibrium Zr2Al phase. It is concluded that the debris retained in the amorphous phase acts as nuclei. After heating to 973 K the grains grow to about 100 nm in diameter and the compound Zr3Al starts to form, that is corresponding to the alloy composition

¿El tamaño y la orientación del grupo intruso afecta a la distancia de iniciación al vuelo en aves?

Wildlife managers use flight initiation distance (FID), the distance animals flee an approaching predator, to determine set back distances to minimize human impacts on wildlife. FID is typically estimated by a single person; this study examined the effects of intruder number and orientation on FID. Three different group size treatments (solitary person, two people side–by–side, two people one–behind–the–other) were applied to Pied Currawongs (Strepera graculina) and to Crimson Rosellas (Platycerus elegans). Rosellas flushed at significantly greater distances when approached by two people compared to a single person. This effect was not seen in currawongs. Intruder orientation did not influence the FID of either species. Results suggest that intruder number should be better integrated into estimates of set back distance to manage human visitation around sensitive species.Los gestores de la fauna utilizan la distancia de iniciación al vuelo (FID), la distancia a la que los animales huyen cuando se les acerca un depredador, para determinar las distancias de respuesta a fin de minimizar el impacto humano en la fauna. La FID es estimada típicamente por una sola persona; este estudio examinó los efectos del número y de la orientación del intruso en la FID. Se aplicaron tres tratamientos distintos de tamaño del grupo (persona solitaria, dos personas una al lado de la otra, dos personas una detras de la otra) a currawongs cálidos (Strepera graculina) y a pericos elegantes (Platycerus elegans). Los pericos elegantes huían a distancias perceptiblemente mayores cuando se le acercaban dos personas que cuando se le acercaba una sola. Este efecto no fue observado en los currawongs pálidos. La orientación del intruso no influenció en la FID de ninguna especie. Los resultados sugieren que el número de intrusos debería ser considerado en las estimaciones de las distancias de respuesta, para poder gestionar las visitas de personas cerca de especies sensibles

Student Interaction with Online Course Content: Build It and They Might Come

Online learning continues to expand at educational institutions around the globe. Educators must better understand how interaction with online course content impacts student engagement and learning. Advances in technology amplify the imperative to gain further insights into how delivery of course materials can enhance and support the learning process. This study investigates student patterns of access to instructional resources provided in an asynchronous online digital literacy course offered at a regional university in the United States. Frequency counts and access rates collected from a learning management system were used to assess patterns of student retrieval of course materials in four categories: core materials, direct support, indirect support and ancillary materials. Results were consistent with student survey responses and indicate that students selectively access course content based upon the degree to which they perceive it will positively influence performance and outcomes on assignments and assessments

Kangaroo Harvesting And The Conservation Of Arid And Semi-Arid Rangelands

This article argues that a reduction in sheep numbers within the sheep rangelands would lead to an increase in kangaroos, improvement in the vegetation, and a reduction in soil erosion. An increase in the market value of kangaroo products would provide a mechanism for this, by making the replacement of sheep by kangaroos an economically attractive proposition, leading to environmental rehabilitation. Thus, a renewable resource (kangaroos) can be used to save a non-renewable resource (the habitat)