Emerging technologies as cognitive tools for authentic learning

Employing emerging technologies in learning is becoming increasingly important as a means to support the development of digital media literacy. Using a theoretical framework of authentic learning and technology as cognitive tools, this paper examined student responses to the infusion of emerging technologies in a large first year teacher education unit over two full iterations, using a design-based research approach. This paper describes the pedagogical context of the intervention, the methodology used, and it presents an analysis of themes emerging from the data relating to the use of emerging technologies

Mechanical properties of plastics predetermined by empirical method

To predetermine the mechanical properties of rigid plastics as a function of plasticizer content and composition, a set of equations has been empirically derived. These relate strain rate, yield stress, temperature, and weight fraction of the plasticizer

Hollow rolling element bearings

A low mass rolling element with a lightweight core and hollow center was developed for use in bearings. The core is plated so as to provide a hard surface and increase the life and reliability of the high speed ball bearings

Space technology's potential for industry

Space technology transfer to civilian applicatio

Large-bore tapered-roller bearing performance and endurance to 2.4 million DN

The operating characteristics and experimental life estimates for 120.65 mm bore tapered roller bearings of two designs under combined radial and thrust loads were determined. A modified standard bearing design was tested at speeds up to 15,000 rpm. A computer optimized, high speed design was tested at speeds up to 20,000 rpm. Both designs were tested at a combined load of 26,700 N (6000 lb) radial load and and 53,400 N (12,000 lb) thrust load. Advanced helicopter transmissions which require the higher-speed capability of tapered-roller bearings also require higher temperature capability (ref. 2). Thus, materials with temperature capabilities higher than the conventional carburizing steels are required

Development and testing of heat transport fluids for use in active solar heating and cooling systems

Work on heat transport fluids for use with active solar heating and cooling systems is described. Program objectives and how they were accomplished including problems encountered during testing are discussed

Strainer fits inside flared-tube fittings

Cylindrical wire-mesh strainer which fits inside flare-tube fittings is readily installed and easily replaced. It has a collar that seats on the tapered shoulder of the male fitting

Dynamical evolution of star forming regions - II. Basic kinematics

We follow the dynamical evolution of young star-forming regions with a wide range of initial conditions and examine how the radial velocity dispersion, $\sigma$, evolves over time. We compare this velocity dispersion to the theoretically expected value for the velocity dispersion if a region were in virial equilibrium, $\sigma_{\rm vir}$ and thus assess the virial state ($\sigma / \sigma_{\rm vir}$) of these systems. We find that in regions that are initially subvirial, or in global virial equilibrium but subvirial on local scales, the system relaxes to virial equilibrium within several million years, or roughly 25 - 50 crossing times, according to the measured virial ratio. However, the measured velocity dispersion, $\sigma$, appears to be a bad diagnostic of the current virial state of these systems as it suggests that they become supervirial when compared to the velocity dispersion estimated from the virial mass, $\sigma_{\rm vir}$. We suggest that this discrepancy is caused by the fact that the regions are never fully relaxed, and that the early non-equilibrium evolution is imprinted in the one-dimensional velocity dispersion at these early epochs. If measured early enough ($<$2 Myr in our simulations, or $\sim$20 crossing times), the velocity dispersion can be used to determine whether a region was highly supervirial at birth without the risk of degeneracy. We show that combining $\sigma$, or the ratio of $\sigma$ to the interquartile range (IQR) dispersion, with measures of spatial structure, places stronger constraints on the dynamical history of a region than using the velocity dispersion in isolation.Comment: 20 pages, 14 figures, accepted for publication in MNRA