Initial operation plan for use of the atmospheric haze recorder.

Thesis (M.A.)--Boston University N.B.: page viii is missing from the original thesis.An airborne telephotometric device (haze recorder) is now being constructed at the Boston University Physical Research Laboratory to collect the data necessary for a study of atmospheric haze. It is expected that this present study will indicate the existence of correlations between haze light intensity and parameters significant in aerial photography. The purpose of this thesis is the provide an operational plan including data reduction and preliminary analysis for the first exploratory test flights. The haze recorder is being constructed to measure up-welling light intensity in a narrow path from horizon through nadir to horizon. The plane of this sweep rotates in 450 intervals relative to the longitudinal axis of the aircraft, and a filter wheel synchronized with the sweep from horizon to horizon passes light alternately through blue, green, and red filters. Thus a three-dimensional plot of up-welling light is formed for each of three spectral ranges. A photomultiplier tube transforms this intensity into an electrical signal which, after amplification, is displayed on an oscilloscope tube and photographed. [TRUNCATED

Controlled synthesis of single-walled carbon nanotubes

The chemistry and applications of carbon nanotubes are critically dependent on nanotube chirality. To date, no one has demonstrated chirality-selective synthesis of single-walled carbon nanotubes from pre-synthesized catalyst nanoparticles. A proposed chemical approach to the mass production of chirality-selective SWNTs is their "cloning" by chemical cutting, decoration with catalyst nanoparticles, and continued growth. The progress of this process will be reviewed. Purified HiPco nanotubes were sidewall functionalized to allow suspension in water and organic solvents. Methods were developed to end-functionalize suspended nanotubes with linkers used to attach preformed catalyst particles. SWNT-catalyst complexes (SWNTcats) were deposited on a surface and exposed to hydrogen to show the feasibility of controlled etching of a single nanotube resulting in removal of the functional linker. To orient the nanotubes for growth, SWNTcats were assembled into open structures on a carbon fiber grid. Vertically oriented carbon nanotube carpets grown by catalytic CVD have received enormous attention because of their suitability in a growing number of important technological applications. An area of concern is the sudden termination of growth that occurs after micron heights are attained. A previously unexplored factor in this termination is the coarsening of the catalyst particles used for growth by Ostwald ripening. The coarsening behavior of Fe catalyst films supported on alumina deposited by atomic layer deposition as a function of thermal annealing in H2 and H2/H2O is demonstrated. The results reveal that the addition of water in water assisted growth of single-walled carbon nanotube carpets may be a means of inhibiting Ostwald ripening through the ability of oxygen and hydroxyl species to reduce diffusion rates of catalyst atoms and thus delay the termination of growth

The Pentagram, No. 2

With the second issue, the editors with to thank all of those who have contributed to the Pentagram. Students and faculty interest has made this issue possible. Your interest and contributions will make future issues possible.https://scholarworks.sfasu.edu/pentagram/1001/thumbnail.jp

Effect of raw and purified carbon nanotubes and iron oxide nanoparticles on the growth of wheatgrass prepared from the cotyledons of common wheat (triticum aestivum)

The increase in global production of nanomaterials has raised concern as to their possible effects on plants that could ultimately affect the human population. The effects on the hydroponic growth of wheatgrass of four types of nanomaterials were studied: raw-single walled carbon nanotubes (SWCNTs), purified-SWCNTs, multi walled carbon nanotubes (MWCNTs), and iron oxide nanoparticles (n-FeOx) as a model of the catalyst residue typically present in CNTs. The germination rate (GR), mean germination time (MGT), shoot length, and a visual score of the plants' growth were determined for wheatgrass over the course of two weeks as a function of exposure to the nanomaterials dispersed in either water or THF (as well as appropriate controls). Raw-SWCNTs, MWCNTs, and n-FeOx show little impact suggesting that the catalyst residue (iron oxide) present in CNTs has little effect. Exposure to purified-SWCNTs dispersed in water shows increased GR (and shoot length), while wheatgrass exposed to purified-SWCNT dispersed in THF had retarded GR, suggesting that SWCNTs act as a carrier for adsorbed organic solvents whose effects are detrimental. A similar but lesser effect was observed for MWCNTs. Interestingly raw-SWCNTs showed no solvent effect, suggesting that the reduction of hydrophobicity of the SWCNTs through functionalisation enables the adsorption and subsequent release of harmful organic solvents. The positive effect of purified SWCNTs when dispersed in water is likely a function of their highly hydrophobic nature facilitating enhanced uptake of water

Identifying Self-Determined Learning Practices Within Social Media for Teacher Professional Development

The collective increase of learner-centered teaching and substantial technology use in the classroom has given instructors potential opportunities to support students in developing lifelong learning skills. The ability to manage one’s own learning is an essential skill for lifelong learners in today’s workforce. Heutagogy, or self-determined learning, suggests that individuals have agency with respect to how, what, and when they learn. Heutagogy provides a framework for making the most of these developments, drawing on established learner-centered education theories. The key principles of heutagogy provide a foundation for designing and developing learning environments using social media. In order for teachers to create learning environment that have opportunities for heutagogical learning, it is imperative that teachers successfully practice these methods themselves. It is generally assumed that effective teacher professional development is critical to effective educational improvements and reforms of educational institutions. However, traditional teacher professional development is constrained by time and space. An alternative form of teacher professional development is needed for continual growth and development. Through the theory of heutagogy and the learner-centered pedagogies on which the theory is founded, this research project seeks to contribute to the understanding of the role of social media in supporting the development of teachers’ self-determined learning practices. In particular, this study aims to examine teachers’ perceptions of using social media for professional development, and show how teachers apply self-determined learning for professional development within these social media environments

PSYCHOLOGICAL VARIABLES IN PRE-ECLAMPSIA: A STUDY IN THREE PARTS

Abstract not availabl