Error diffusion in cell-oriented Fourier-transform computer-generated holograms to compensate for printing constraints

Abstract

Error-diffused quantization has been applied to the generation of cell-oriented computer-generated Fourier transform holograms, resulting in reduced reconstruction errors. Improvements are demonstrated when applied to the algorithms of Lohmann, Lee and Burckhardt after invoking realistic constraints on the minimum size of the printable spot for an electrophotographic laser printer.     

AN ANALYSIS OF PHASE DISTRIBUTION AND TURBULENCE IN DISPERSED PARTICLE/LIQUID FLOWS

An analysis of dilute, turbulent particle/liquid two-phase flow is presented. The three-dimensional conservation equations that govern turbulent motion in solid/fluid flows are derived using ensemble averaging, and the unknown terms in these equations are constituted to achieve closure. These closure terms include the shear stress due to interparticle collisions, the corresponding terms in the Reynolds stress equation, the force and dissipation due to particle-wall collisions, and the interfacial work due to particle/turbulent eddy interaction. The resultant two-fluid model was then evaluated using a computational fluid dynamic (CFD) solver and the predictions were compared with experimental data. Good agreement was observed for a variety of flow conditions.     

Effects of Post-Harvest Handling and Processing on Vitamin Contents of Peas

Vitamin contents of peas were measured at various stages of raw product handling, during 1976–1979 seasons, on different cultivars, on different sizes of peas, at various stages of processing, and at different processing plants. Some cultivar differences were shown in ascorbic acid, carotene, and folic acid, and different sizes of peas contained significantly different amounts of ascorbic acid, carotene, and thiamin contents. Profound effects were observed during blanching and thermal processing of peas. Ascorbic acid, thiamin, vitamin B₆, and niacin contents of canned peas were significantly (95% level) lower than those of fresh peas. Also some significant differences in vitamin contents of canned peas among different processing plants were observed.     

Phase Equilibria in the System CaF2-AlF3-Na3AlF6 and Part of the System CaF2-AlF3-Na3AlF6-Al2O3

The complete phase-equilibrium diagram of the system CaF₂-AlF₃-Na₃AlF₆ and the subsolidus portion of the system CaF₂-AlF₃-Na₃AlF₆-Al₂O₃ were established from microscopic, powder X-ray diffraction, quench, and DTA data obtained from samples encapsulated in sealed tubes and either reacted in the solid state or melted and recrystallized. The system Na₃AlF₆-CaF₂ contains a simple eutectic with no compound formation or solid solution. The system CaF₂-AlF₃-Na₃AlF₆ contains two ternary compounds, NaCaAlF₆ and NaCaAl₂F₉, which melt incongruently at 735° and 712°C, respectively; NaCaAlF₆ exists in three polymorphic forms with transitions at 610° and 722°C and NaCaAl₂F₉ is body-centered cubic with a₀= 10.765 Å. The three binary and two ternary compounds divide the system into eight compatibility triangles. Along the NaCaAlF₆-Na₃AlF₆ join, 7 mol% NaCaAlF₆ is soluble in α-cryolite at 525° and 42% in β-cryolite at 731°C. The quaternary system Na₃AlF₆-AlF₃-CaF₂-Al₂O₃ contains eight compatibility tetrahedra.     

A Canadian Approach To Drought Monitoring For Famine Relief in Africa

ABSTRACT

Poor water supply is the dominant issue in African agriculture. A project aimed at reducing the impact of drought onfood supply levels in Africa is described. The result was a computer software package for analysis of monthly rainfall records which can be operated on a desktop computer. Referencing of current weather analysis results against historical expectations was a major part of the system design. Another feature was to combine current records with climate normals to project mid-rainy season growing conditions to post-harvest crop estimates. A simple simulation model is used to relate rainfall records to evapotranspirationpotential to generate crop water use and soil moisture reserve estimates. Initial scale of application was the entire African continent, but a downsized version has been produced for Zambia. Similar versions could be produced for other countries. The overall project proposed a multi-disciplinary approach to monitoring, in which the weather based system described here is only one component. Satellite technology is a key link to this system. Other applications of the system include both training and long-term planning as well as crop marketing support.     

Records of change in salt marshes: a radiochronological study of three Westerschelde (SW Netherlands) marshes

Three salt marshes on a 50-km transect along the north bank of the Westerschelde Estuary were investigated to determine whether salt marshes in the estuary had responded to shipping channel modifications in recent decades. Marsh accretion rates were estimated mainly from 137Cs profiles with further evidence from 241Am because changes in both rate of deposition and nature of the accreting material precluded use of standard 210Pb(excess) dating models. The 137Cs profiles usually show peaks corresponding to atmospheric deposition from the 1963 fallout maximum and sometimes from the Chernobyl accident, although intervening enhanced 137Cs activities derived from the nuclear reprocessing marine discharges of Sellafield and La Hague are clearly discernible. In all three marshes (Ritthem at the mouth of the estuary and Zuidgors and Waarde at 20 and 45 km upstream), a marked, near-coincident change in the rate of accumulation and in the grain size of material deposited occurred around 1980. This may be related to a combination of channel deepening and straightening operations undertaken in the mid-1970s and/or natural changes in winter wave climate.     

Aging of distribution cables in service and its simulation in the laboratory

This study focuses on efforts to characterize aging occurring in 15 kV distribution cables in a dry climate. It has been shown that similar changes can be produced by a suitably planned accelerated thermal aging testing in the laboratory. The Arrhenius equation is used for establishing the accelerated aging test parameters. Different modes of statistical analysis namely analysis of variance (ANOVA), Andersen-Darling test for normality, F-test, t-test are performed to validate results from accelerated aging tests with field aging