Community Service for 4-H Club Members

COMMUNITY SERVICE ••• that\u27s what happens when your club, your neighborhood, community groups and local government work together to build your community into the kind of place you want it to be. The parks and playgrounds, churches, schools and hospitals that serve a community don\u27t just happen. . Leaders interested in community service were necessary to help create these facilities. In a democracy, such voluntary leadership helps make and keep us strong. When you take a small step in community service you are on the road to becoming a community leade

A comparative study of attitudes and values at different levels of optometric education

The goals of this study were three-fold. First, the dominant values as measured by Spranger\u27s Study of Values test were determined for optometry students as a group. Secondly, these values were compared within the group of optometry students to see if any differences existed among classes. Finally, the values were compared to both professional and undergraduate student groups. Optometry students as a group were found to have high aesthetic and low political and religious scores relative to the collegiate norms. The only significant difference found when the optometry classes were compared to each other was the social scale for the first versus the fourth year class. Several significant differences of values were seen between optometry and medical students

Plasma flows in the Alcator C-Mod scrape-off layer

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, February 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 227-234).Near-sonic parallel plasma flows are persistently observed in the scrape-off layer (SOL) of tokamaks, at locations far from material surfaces. Ballooning-like transport asymmetries are thought to be a principal driver for the strong parallel flows, a hypothesis supported by the observation of steep high-field side pressure profiles in double-null discharges. Yet parallel flow can also arise as a result of toroidal plasma rotation and/or neoclassical Pfirsch-Schliiter currents. In addition, the mechanism that closes the mass-flow loop back onto itself has remained elusive. To investigate these phenomena, a novel magnetically-actuated scanning probe has been deployed on the high-field side in Alcator C-Mod. This probe, along with two other scanning probes on the low-field side, measure the total plasma flow vector at these locations: parallel flows, perpendicular E_r x B drifts and radial fluctuation-induced particle fluxes. Boundary layer flows have been systematically examined as magnetic topology (upper versus lower-null) and plasma density were changed. It is found that the plasma flow pattern can be decomposed into two principal parts: (1) a drift-driven component, which lies within a magnetic flux surface and is divergence-free and (2) a transport-driven component which gives rise to parallel flows on the high-field side scrape-off layer.(cont.) Toroidal rotation, Pfirsch-Schlilter and transport-driven contributions are unambiguously identified. Parallel flows are found to dominate the high-field particle fluxes; the total poloidally-directed flow carries one half of the particle flux arriving on the inner divertor. As a result, convection is also found to be an important player in high-field side heat transport. In contrast, E_r x B plus parallel flows yield a mostly-toroidal flow component in the low-field SOL. The magnitude of the transport-driven flow component is found to be quantitatively consistent with radial fluctuation-induced particle fluxes measured on the low-field side, identifying this as the primary driver. In contrast, fluctuation-induced flux measurements on the high-field side midplane are found to be essentially zero, thereby excluding an 'inward pinch' effect as the mechanism that closes the mass-flow loop in this region.by Noah M. Smick.Ph.D

Positive fusional reserve changes associated with the magnitude of lens power prescribed

Positive fusional reserve changes associated with the magnitude of lens power prescribe

A comparison of blue-light transmissions through blue-control lenses

Abstract: Background: Many people are exposed to blue light through devices such as cellular phones, tablets and computers. Such light may affect us depending on its wavelength and blue-control lenses are now frequently used, thus influencing our daily lives. Aim: This study provides an analysis of the transmissions of blue light through 10 lenses with different blue-control coatings. Setting: The study was conducted at the Department of Optometry, University of Johannesburg, South Africa. Methods: Transmission curves of 10 lenses with different blue-control reflective coatings were compared. A control lens (the achromatic lens) was also included. The Cary Varian 5000 photo spectrophotometer from the Department of Physics at the University of Johannesburg was used to measure the spectral transmittances of these lenses with refractive indices ranging from 1.5 to 1.6. The geometric centre of each lens was aligned with the measuring axis of the spectrophotometer and spectral transmittance between 300 nm and 500 nm was measured. Results: For the 10 lenses studied, the transmission of wavelengths below 460 nm varied from 48% to 69% and for wavelengths between 460 nm and 500 nm from 33% to 55%. The differences between lenses were greater than 20%. If we changed the range of transmission to between 480 nm and 500 nm, the percentage transmitted varied from approximately 71% to 83% to give about a 12% difference between all the lenses. Conclusion: Not all lenses displayed similar transmissions of blue light and different manufacturers do not agree as to what percentage of blue light should be reflected or transmitted

Oblique ion collection in the drift-approximation: how magnetized Mach-probes really work

The anisotropic fluid equations governing a frictionless obliquely-flowing plasma around an essentially arbitrarily shaped three-dimensional ion-absorbing object in a strong magnetic field are solved analytically in the quasi-neutral drift-approximation, neglecting parallel temperature gradients. The effects of transverse displacements traversing the magnetic presheath are also quantified. It is shown that the parallel collection flux density dependence upon external Mach-number is $n_\infty c_s \exp[-1 -(M_{\parallel\infty}- M_\perp\cot\theta)]$ where $\theta$ is the angle (in the plane of field and drift velocity) of the object-surface to the magnetic-field and $M_{\parallel\infty}$ is the external parallel flow. The perpendicular drift, \M_\perp, appearing here consists of the external \E\wedge\B drift plus a weighted sum of the ion and electron electron diamagnetic drifts that depends upon the total angle of the surface to the magnetic field. It is that somewhat counter-intuitive combination that an oblique (transverse) Mach probe experiment measures.Comment: Revised version following refereeing for Physics of Plasma