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The theory of the Šolc birefringent filter is complicated and the general formulae describing its optical properties do not invite to any simple physical picture. Due to these formal difficulties, many of its inherent possibilities have not been fully appreciated. In this paper we point out some new possibilities for filters based on this general design. The detailed shape of the transmission profile is a function of the angles of the crystal plate optic axes. It is shown how unwanted transmission sidelobes can be suppressed to any desired level by altering the distribution of plate angles. By the same means, the transmission band can be split into two symmetrically placed replicas, and the distance between the two bands can be varied. In this way the filter can easily be tuned over half the free spectral range. Some of the error sources that are important to filter performance are discussed. An expression is given for the amount of parasitic light introduced by errors in the orientation of the plate optic axes and it is found that errors as large as 0°.5 can be tolerated. A laboratory experiment with 16 birefringent plates has shown that accuracies an order of magnitude better than this figure can easily be achieved. Manufacturing errors in the thickness of the plates can be compensated for by assembling the pile of plates in a particular way. The very strict tolerances usually quoted can therefore be considerably relaxed. [ABSTRACT FROM AUTHOR]

A model is proposed for the relationship between net photosynthetic rate (N) and light intensity at a given concentration of CO2 in the air ([CO2]a). The model provides a prediction of the sum of the diffusion resistances (Σr), the capacity (K) of the leaf to fix CO2, the concentration of CO2 at the point of photosynthesis ([CO2]g), and the respiration rate (R). The model fits the available data well and provides a framework by which future research may be guided. The calculated values of [CO2]g decreased from [CO2]a at the compensation point to a nearly constant value at high light intensities. [CO2]g at high light intensities range from 32 to 144 μl/l (volume) depending on the species. When these values of [CO2]g are used in the diffusion equation, the resulting levels of the mesophyll resistance (rm) are lower than those calculated by using the assumptions that [CO2]g equals zero. The plants which had the higher photosynthetic rates at a given light intensity and [CO2]a had greater values of [CO2]g than those with lower photosynthetic rates. The calculated rates of respiration of wheat leaves were twice as high as those measured in the dark. This suggests that the light respiration rate may be twice as great as the dark respiration rate at the same temperature. The calculated values of K demonstrate variability within and between species. The maximum N was independent of K. A relationship between K and the maximum quantum efficiency, at constant levels of [CO2]g, was demonstrated in several species. The Σr was inversely related to the maximum rate of photosynthesis for the species investigated. The values of rm calculated for cotton were inversely related to [CO2]a suggesting that the transfer of CO2 in the cell may involve a concentration dependent chemical reaction in addition to or rather than a physical diffusion process. [ABSTRACT FROM AUTHOR]

The article offers information regarding the over-all specific volume of kapok fibers. It is an important physical property of the fiber mass as it is the ratio of over-all volume to the weight of the fibers since the specific volume depends on the pressure to which it is subjected. Kapok fibers are used as filling materials like bedding, upholstery and the production of buoyant and life-saving equipment. Kapok tree of Java is a species of the family Ceiba pentandra which has the highest commercial reputation due to a careful control in cultivation and the use of effective methods for the cleaning and opening of the raw fiber and the establishment of the standard system for grading the product.

Structural-relaxation data in liquids indicate the presence of a distributed relaxation-time spectrum. A physical model for this distribution is proposed. The model is used to calculate the dynamical behavior of fluctuations in an order parameter describing the local liquid structure. This is used to predict both compressional and shear relaxation dynamics. The equation of motion for the ordering parameter includes explicitly both the effects of an elementary rate process and simple diffusion. The calculated distribution of relaxation times for compressional strain is similar to a Cole-Davidson distribution function with a width parameter near 0.5. The predictions for the frequency dependence of the compressibility and shear rigidity agree reasonably well with experimental data in a number of liquids. [ABSTRACT FROM AUTHOR]

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An extension of a method previously described is used to determine capture crosssections for shallow traps of CdS-crystals in the vicinity of the conduction band. The data are obtained by measurement of photoconductivity induced by sinusoidally modulated light of λ ≈ 600 mμ. The results are as follows: σ ≈ 1,5 to 6 · 10 cm for traps at 0.12 ev (below the conduction band); σ ≈ 5 to 9 · 10 cm for traps between 0.2 and 0.6 ev; σ ≈ 10 to 10 cm for traps at 0.7 to 0.8 ev. [ABSTRACT FROM AUTHOR]

The aerial paths described by plumed seeds shed from motionless plants and moving in steady horizontal winds with vertical convection currents are discussed and formulae established for calculating them both roughly and fairly accurately. Most of the formulae are simple and of practical use to botanists. Example calculations show the effect of release height, convection velocity, and the terminal velocity of fall of the seed in still air, and the various trajectory shapes concocted can be used to account for seed behaviour as observed and reported in the literature. It is also shown how, under certain conditions, some approximate calculations can be very much in error. [ABSTRACT FROM AUTHOR]

Copyright of Rheologica Acta is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Approximately two hundred books on mathematical programming have been published during the past eight years. Most workers in this field have immediate access to only a minor fraction of these, but would have at least vicarious access to many of the rest through book reviews if only they knew where to look. That is the primary motivation for this bibliography of book reviews published during the years 1965-1972. A secondary reason is simply to furnish a reasonably comprehensive list of recent books on mathematical programming. [ABSTRACT FROM AUTHOR]

Copyright of Zeitschrift für Physik is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)