Magnetooptic color effects in bismuth garnet domains

Domains in magnetic materials having a dispersive Faraday coefficient appear in various colors when viewed by the Faraday effect. If the polarizer and analyzer are slightly uncrossed, domains appear in four colors, three spectral colors and black, depending on the local normal component of magnetization. A theory is presented for this effect. Experimental values of color observed in bismuth substituted garnet films as a function of normal applied field agree with the theory. This effect permits one to discern the average normal component of magnetization at a spot on a micrograph from the color at, that location. Besides the usual bubbles and stripes, unusual domains such as bubble spikes and diamonds and stripe arrays in which the normal component of the magnetization does not change sign are reported.     

Calculating effective board thermal parameters from transientmeasurements

The paper presents a method to find the effective thermal conductivity and effective volumetric heat capacity values of PWBs from the results of thermal transient measurements and a series of subsequent evaluation steps. Various powering and temperature sensing methods were investigated. The experiments show the feasibility of creating a method for obtaining effective thermal parameters of printed wiring boards with the help of usual thermal transient testers     

"Lorentz" microscopy of stripe domain films with protons

A new method is reported for observing the in-plane component of magnetic structure in stripe domain films. Stripe domain films act as a Faraday-effect diffraction grating, and deflect light beams in a way reminiscent of electrons being deflected by the Lorentz force in a magnetic thin film. The direction of the stripes is that of the local in-plane magnetization vector. Thus the angle of deflection is perpendicular to the local in-plane magnetization, as is the case for Lorentz deflection. Micrographs are presented demonstrating that with a displaced aperture one can perform with light the analogues of the two modes of Lorentz microscopy: light-field microscopy in the defocused mode and dark-field microscopy with light normal to the film plane. In the defocused mode, walls appear as either bright streaks or dark streaks; if one focuses on the opposite side of the film the bright walls become dark and vice-versa. In the dark-field mode the contrast of the dark regions and the bright regions can be reversed by moving the aperture.     

Identification and Field Evaluation of Attractants for the Cranberry Weevil, <Emphasis Type="Italic">Anthonomus musculus</Emphasis> Say

Studies were conducted to develop an attractant for the cranberry weevil, Anthonomus musculus, a pest of blueberry and cranberry flower buds and flowers in the northeastern United States. In previous studies, we showed that cinnamyl alcohol, the most abundant blueberry floral volatile, and the green leaf volatiles (Z)-3-hexenyl acetate and hexyl acetate, emitted from both flowers and flower buds, elicit strong antennal responses from A. musculus. Here, we found that cinnamyl alcohol did not increase capture of A. musculus adults on yellow sticky traps compared with unbaited controls; however, weevils were highly attracted to traps baited with the Anthonomus eugenii Cano aggregation pheromone, indicating that these congeners share common pheromone components. To identify the A. musculus aggregation pheromone, headspace volatiles were collected from adults feeding on blueberry or cranberry flower buds and analyzed by gas chromatography-mass spectrometry. Three male-specific compounds were identified: (Z)-2-(3,3-dimethyl-cyclohexylidene) ethanol (Z grandlure II); (Z)-(3,3-dimethylcyclohexylidene) acetaldehyde (grandlure III); and (E)-(3,3- dimethylcyclohexylidene) acetaldehyde (grandlure IV). A fourth component, (E)-3,7-dimethyl-2,6-octadien-1-ol (geraniol), was emitted in similar quantities by males and females. The emission rates of these volatiles were about 2.8, 1.8, 1.3, and 0.9 ng/adult/d, respectively. Field experiments in highbush blueberry (New Jersey) and cranberry (Massachusetts) examined the attraction of A. musculus to traps baited with the male-produced compounds and geraniol presented alone and combined with (Z)-3-hexenyl acetate and hexyl acetate, and to traps baited with the pheromones of A. eugenii and A. grandis. In both states and crops, traps baited with the A. musculus male-produced compounds attracted the highest number of adults. Addition of the green leaf volatiles did not affect A. musculus attraction to its pheromone but skewed the sex ratio of the captured adults towards females. Although the role of plant volatiles in host-plant location by A. musculus is still unclear, our studies provide the first identification of the primary A. musculus aggregation pheromone components that can be used to monitor this pest in blueberry and cranberry pest management programs.     

Practical constraints in the kinetic plot representation of chromatographic performance data: theory and application to experimental data

It is demonstrated that the kinetic plot representation of experimental plate height data can also account for practical constraints on the column length, the peak width, the viscous heating, and the mobile-phase velocity without needing any iterative solution routine. This implies that the best possible kinetic performance to be expected from a given tested support under any possible set of practical optimization constraints can always be found using a directly responding calculation spreadsheet template. To show how the resulting constrained kinetic plots can be used as a powerful design and selection tool, the method has been applied to a series of plate height measurements performed on a number of different commercial columns for the same component (butyl-parabene) and mobile-phase composition. The method, for example, allows one to account for the fact that the advantageous solutions displayed by the silica monolith and 5 microm particle columns in the large plate number range of the free kinetic plot are no longer accessible if applying a maximal column length constraint of Lmax = 30 cm. In the plate number range that remains accessible, the investigated sub-2 mum particle columns in any case perform (at least for the presently considered parabene separation) better than the 3.5 mum particle columns or silica monolith, especially if considering the use of system pressures exceeding 400 bar. The constrained kinetic plot method can also be used to select the best-suited column length from an available product gamma to perform a separation with a preset number of plates. One of the optimization results that is obtained in this case is that sometimes a significant gain in analysis time can be obtained by selecting a longer column, yielding the desired plate number at a larger velocity than that for a shorter column.