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NOTE ON THE EFFECT OF A COVER GLASS IN REFLECTANCE MEASUREMENTS
Abstract
It has b een found from theoretical considerations that the use of a cover glass may result in an error of as much as 10 percent when two diffusing surfaces, one light and one dark, are compared for apparent reflectance. The error arises from multiple reflections between sample and cover glass, the lighter sample obtaining much more added illumination from this cause than the darker. The error de-pends on the angular distribution of the illuminant, the angle of view, and the diffusing characteristics of the samples as well as their reflectances.
... In a solar concentration system, it is extremely difficult to avoid the deviation angle relative to the aligned optical path even with the state-of-the-art tracking apparatus 6,7 . The deviated light beams can lead to undesired efficiency loss owing to the low absorption at high incident angles 8,9 . One way to address the issue is to increase the omnidirectionality of reflection suppression on device surface. ...
GaInP/GaAs/Ge triple-junction concentrator solar cells with significant efficiency enhancement were demonstrated with antireflective ZnO nanoneedles. The novel nanostructure was attained with a Zn(NO3)2-based solution containing vitamin C. Under one sun AM 1.5G solar spectrum, conversion efficiency of the triple-junction device was improved by 23.7% via broadband improvement in short-circuit currents of 3 sub-cells after the coverage by the nanoneedles with a graded refractive index profile. The efficiency enhancement further went up to 45.8% at 100 suns. The performance boost through the nanoneedles also became increasingly pronounced in the conditions of high incident angles and the cloudy weather, e.g. 220.0% of efficiency enhancement was observed at the incident angle of 60°. These results were attributed to the exceptional broadband omnidirectionality of the antireflective nanoneedles.
... After this the yellow board with acetate and Tack-trap had the lowest spectral reflectance of the three boards measured. The percentage reflectance of the treatments above 510 nm responded in a way that would be expected by a clear covering of a surface (Judd and Gibson, 1936); . the percentage refl ectance decreased with more cover; ng. ...
Froggattls apple leafhopper {FALH} is a minor pest of apple in New Zealand although it has the potential to increase its pest status through insecticide resistance and any reduction of insecticide use aimed at ‘key pests’ • This thesis gathered basic biological information to rationalise any future management of this insect.
Yellow sticky boards were used to sample FALH adults in three orchards under different management regimes and the adults of the egg parasite Anagrus armatus in two orchards. Sampling of overwintering eggs, summer eggs and nymphal instars occurred only in an abandoned orchard.
Regular insecticide applications in a commercial orchard reduced the numbers of FALH and A. armatus to very low levels compared to those trapped in an abandoned orchard. All life stages of FALH sampled over two seasons in an abandoned orchard strongly suggested the presence of at least two, and possibly a partial third, generation. A similar temporal distribution was found in blackberry adjacent to an abijndoned orchard. Overwintering eggs summer eggs and nymphs showed no consistent preference for any of the examined positions within the tree. Adult numbers trapped on yellow sticky boards increased with height, due to a disproportionate increase of males with height in relation to females.
The description of the pattern of distribution was established using the indices of Taylor's power law and Iwao's patchiness regression for overwintering eggs (randomly dispersed, cohesive groups of eggs), for two seasons of summer eggs (a clumped distribution with a basic component of individuals in both seasons) and two seasons of nymphal instars (basically random or clumped groups of individuals). Of the 27 distributions analysed, Taylor's power law gave the better data fit on 26 occasions. Only four distributions were described differently by the two models.
FALH numbers built up quickly in a previously uninfested orchard through natural increase and migration. Migration over short distances was mainly influenced by the condition of the host plant and the prevailing wind.
Conservative estimates of parasitism by A. armatus were established for overwintering FALH eggs (30-53%) and summer FALH eggs (20-100%) in an abandoned orchard. Yellow sticKy board samples indicated that the life cycle of A. armatus was well synchronised with that of FALH.
The appropriate base temperatures for different development stages of FALH were found to be between 9.7 and 11.0°C by laboratory studies and field measurement. A thermal constant of 463.5 ±10.5Do from egg to adult was established from laboratory studies.
Acetate sheets placed on the yellow sticky boards only reduced the spectral reflectance by a small amount but improved sampling efficiency and trap storage. The yellow sticky boards were found to sample larger proportions of the FALH population in relation to the D-Vac (at all densities) and Johnson and Taylor suction trap (only at high densities). Sticky boards appeared to preferentially sample males in relation to females. Higher placement of sticky boards in the tree reduced the number of leafhoppers, other than FALH, caught.
A rational approach to control, based on all available data for this insect, is discussed.
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