Construction of the New Pressure-Insulated Electrostatic Generator at the State University of Iowa (Abstract)

The electrostatic generator will be housed in a new underground laboratory connected to the physics building by a tunnel. Since last fall work has been proceeding on the construction of the generator inside of the 2½\u27 by 50\u27 steel tank. This pressure vessel will allow operation of the generator at pressures up to 8 atmospheres absolute. An intermediate electrode has been introduced. Two cotton fabric woven-endless belts with a linear speed of about 5,000\u27 per minute will charge the high potential electrode. The 22\u27 accelerating tube is being constructed of short porcelain sections with steel spinnings serving as accelerating electrodes

So you want to farm : what does it take? What can you make?

"Farming means different things to different people. To some, it is a business in which farm managers employ their talents in producing food and fiber, thereby earning a return for their labor and equity. To others, it is a way of life - a good place to raise a family and escape some of the frustrations of urban living. If a farm does not have to support a family, it can be a good investment and greatly add to the family's living and enjoyment."--First page.Ronald L. Plain and Thomas G. Brown (Department of Agricultural Economics, College of Agriculture)Revised 12/86/6

The Resonance in the B-P-a Reaction

The yield of alpha particles of range greater than 2 cms. from boron bombarded by protons has been studied as a function of bombarding energy in the range from 100 to 200 ekv, using a thin target, either methyl borate or boron trifluoride at pressures of 1 mm. of Hg. The yield vs. energy curve shows an approximately exponential rise on which is superposed a sharp (half breadth ~ 6 ekv) intense line at 150 ± ekv. There is some indication of a weaker and much broader line at 190 ekv. Number range curves are not yet available, but the appearance of pulses on the oscillograph screen leads us to suppose that the high yield (line) at 150 ekv is due to emission of a homogeneous long-range group

Mapping the Electromagnetic Near-Field Enhancements of Gold Nanocubes

International audienceWe imaged and quantitatively characterized electromagnetic hot spots near the surfaces of plasmon resonant gold nanocubes. The strongest fields are localized at the nanocube corners as compared to those on the sides. The near-field enhancement on the surface of the cube was imaged as a function of incident polarization, leading to information on the localization of fields on specific regions on the surface. We found that the field intensity drops dramatically when the nanocube corner is slightly tilted with respect to the incident laser polarization. This dramatic dependence on angle was verified by electrodynamics simulations. These results will enable the use of gold nanocubes in field enhancement applications and refractive-index sensing

Plasmon-based photopolymerization: near-field probing, advanced photonic nanostructures and nanophotochemistry

Cataloged from PDF version of article.Hybrid nanomaterials are targeted by a rapidly growing group of nanooptics researchers, due to the promise of optical behavior that is difficult or even impossible to create with nanostructures of homogeneous composition. Examples of important areas of interest include coherent coupling, Fano resonances, optical gain, solar energy conversion, photocatalysis, and nonlinear optical interactions. In addition to the coupling interactions, the strong dependence of optical resonances and damping on the size, shape, and composition of the building blocks provides promise that the coupling interactions of hybrid nanomaterials can be controlled and manipulated for a desired outcome. Great challenges remain in reliably synthesizing and characterizing hybrid nanomaterials for nanooptics. In this review, we describe the synthesis, characterization, and applications of hybrid nanomaterials created through plasmon-induced photopolymerization. The work is placed within the broader context of hybrid nanomaterials involving plasmonic metal nanoparticles and molecular materials placed within the length scale of the evanescent field from the metal surface. We specifically review three important applications of free radical photopolymerization to create hybrid nanoparticles: local field probing, photoinduced synthesis of advanced hybrid nanoparticles, and nanophotochemistry

Distribution in Angle of Alpha Particles from Li7 + H1

We find the distribution of alpha particles from Li7 + H1 is not spherically symmetric, a result in disagreement with the conclusions of earlier investigators,1 who, however, worked at rather low energies only. Thick target data at energies as low as 150 ekv show the presence of a small cos2Θ term and may be represented by I(Θ) = 1 + .16 Cos2Θ while at 440 ekv the asymmetry is very marked, the data being well represented by I(Θ) = 1 + .7 Cos2 Θ. Because of the rapid increase of yield with energy, it is to be expected that thin target data will show a slightly but only slightly greater cos2 0 term. Preliminary thin target data appear to bear this out

Distribution on Angle of Alpha Particles from F19 + H1

The distribution in angle of long range alpha particles from fluorine bombarded by protons has been studied in the range 270 - 440 ekv. The distribution shows a very strong concentration in the forward direction. Intensity as a function of angle in the center of mass system may be represented by the equation I (Θ) = 1 + .77 CoS Θ + .17 CoS2 Θ for a bombarding energy of 375 ekv. The distribution shows little, if any, energy dependence and in particular is not observably different at 330 ekv bombarding energy. Targets were prepared by electrolyzing hydrogen fluoride on tantalum and were fairly thin, the apparent half width of the 330 ekv gamma ray line being 40 ekv or less

Evaluation of the limitations and methods to improve rapid phage-based detection of viable Mycobacterium avium subsp. paratuberculosis in the blood of experimentally infected cattle

Background Disseminated infection and bacteraemia is an underreported and under-researched aspect of Johne’s disease. This is mainly due to the time it takes for Mycobacterium avium subsp. paratuberculosis (MAP) to grow and lack of sensitivity of culture. Viable MAP cells can be detected in the blood of cattle suffering from Johne’s disease within 48 h using peptide-mediated magnetic separation (PMMS) followed by bacteriophage amplification. The aim of this study was to demonstrate the first detection of MAP in the blood of experimentally exposed cattle using the PMMS-bacteriophage assay and to compare these results with the immune response of the animal based on serum ELISA and shedding of MAP by faecal culture. Results Using the PMMS-phage assay, seven out of the 19 (37 %) MAP-exposed animals that were tested were positive for viable MAP cells although very low numbers of MAP were detected. Two of these animals were positive by faecal culture and one was positive by serum ELISA. There was no correlation between PMMS-phage assay results and the faecal and serum ELISA results. None of the control animals (10) were positive for MAP using any of the four detection methods. Investigations carried out into the efficiency of the assay; found that the PMMS step was the limiting factor reducing the sensitivity of the phage assay. A modified method using the phage assay directly on isolated peripheral blood mononuclear cells (without PMMS) was found to be superior to the PMMS isolation step. Conclusions This proof of concept study has shown that viable MAP cells are present in the blood of MAP-exposed cattle prior to the onset of clinical signs. Although only one time point was tested, the ability to detect viable MAP in the blood of subclinically infected animals by the rapid phage-based method has the potential to increase the understanding of the pathogenesis of Johne’s disease progression by warranting further research on the presence of MAP in blood