Reinforcement of polymeric structures with asbestos fibrils

Investigation determines structural potential of asbestos fibrils. Methods are developed for dispersing macrofibers of the asbestos into colloidal-sized ultimate fibrils and incorporating these fibrils in matrices without causing reagglomeration

The reinforcement of polymeric structures by asbestos fibrils Final report, 1 Apr. 1965 - 30 Apr. 1966

Dispersion techniques for asbestos fibril reinforcement of polymeric structures, and tensile strength data on reinforced composite

Examination of Externalizing Behaviors within General Education, At-Risk, and Special Education Preschool-Aged Classrooms

This study examined the natural occurrence of externalizing behaviors within six preschool classrooms (two general education classrooms, two at-risk classrooms, and two special education classrooms). Approximately 100 direct observation minutes were collected in each of the six classrooms to obtain measures of student off-task and disruptive behavior. No significant off-task differences were found across the three classroom types. However, a significant difference in disruptive behavior was found between special education and general education classrooms and also between special education and at-risk classrooms. The most commonly observed disruptive behaviors across all six classrooms were talking out, being out of area, and inappropriate behavior. Implications and directions for future study are discussed

Examination of Externalizing Behaviors within General Education, At-Risk, and Special Education Preschool-Aged Classrooms

This study examined the natural occurrence of externalizing behaviors within six preschool classrooms (two general education classrooms, two at-risk classrooms, and two special education classrooms). Approximately 100 direct observation minutes were collected in each of the six classrooms to obtain measures of student off-task and disruptive behavior. No significant off-task differences were found across the three classroom types. However, a significant difference in disruptive behavior was found between special education and general education classrooms and also between special education and at-risk classrooms. The most commonly observed disruptive behaviors across all six classrooms were talking out, being out of area, and inappropriate behavior. Implications and directions for future study are discussed

Suppression of electron scattering resonances in graphene by quantum dots

Transmission of low-energetic electrons through two-dimensional materials leads to unique scattering resonances. These resonances contribute to photoemission from occupied bands where they appear as strongly dispersive features of suppressed photoelectron intensity. Using angle-resolved photoemission we have systematically studied scattering resonances in epitaxial graphene grown on the chemically differing substrates Ir(111), Bi/Ir, Ni(111) as well as in graphene/Ir(111) nanopatterned with a superlattice of uniform Ir quantum dots. While the strength of the chemical interaction with the substrate has almost no effect on the dispersion of the scattering resonances, their energy can be controlled by the magnitude of charge transfer from/to graphene. At the same time, a superlattice of small quantum dots deposited on graphene eliminates the resonances completely. We ascribe this effect to a nanodot-induced buckling of graphene and its local rehybridization from sp$^{2}$ to sp$^{3}$ towards a three-dimensional structure. Our results suggest nanopatterning as a prospective tool for tuning optoelectronic properties of two-dimensional materials with graphene-like structure.Comment: The following article has been submitted to Applied Physics Letters. If it is published, it will be found online at http://apl.aip.or

Rashba splitting of 100 meV in Au-intercalated graphene on SiC

Intercalation of Au can produce giant Rashba-type spin-orbit splittings in graphene but this has not yet been achieved on a semiconductor substrate. For graphene/SiC(0001), Au intercalation yields two phases with different doping. Here, we report the preparation of an almost pure p-type graphene phase after Au intercalation. We observe a 100 meV Rashba-type spin-orbit splitting at 0.9 eV binding energy. We show that this giant splitting is due to hybridization and much more limited in energy and momentum space than for Au-intercalated graphene on Ni

Exploratory studies of contact angle hysteresis, wetting of solidified rare gases and surface properties of mercury Final report

Contact angle hysteresis, wetting of solidified rare gases, and surface properties of mercur