STEAM DRYING TECHNOLOGIES: JAPANESE R&D

This report reviews some fundamental and practical aspects of steam drying technologies based mainly on studies published in Japan. Steam drying kinetics, and some industrial technologies particularly for drying of foods, textiles and sludges are reviewed with focus on quality of dried material, drying time, dryer selection and energy recovery from steam dryer exhaust. For energy recovery, heat pump technologies are outlined along with characteristics of different types of steam compressors. A new process is proposed for steam drying; it combines a direct-indirect dryer followed by a direct steam dryer for internal moisture removal.     

Changes in Δ5- and Δ7-sterols during germination and seedling development ofCucurbita maximaduring germination and seedling development ofCucurbita maxima

While seeds ofCucurbita maxima contain both Δ⁵- and Δ⁷-sterols, the former, which have been described earlier, now have been found to disappear during germination. This suggests that a function exists for the Δ⁵-compounds only in the early part of the life cycle ofC. maxima, unlike most of the other higher plants studied. In contrast to the Δ⁵-sterols, the level of Δ⁷-sterols increased during germination as well as during seedling development and maturation. The period of transition between germination and seedling development appeared to be of special importance in terms of sterol changes. This period represented a surge of sterol biosynthesis with an ontogenetic shift in sterol composition from approximately equal amounts of 24α- and 24β-ethyl stereochemistry to a predominance of the former. The sterol composition of the mature plants included only about 5% of the 24β-ethylsterols. The configurational relationships were demonstrated by high resolution¹H-NMR. The sterols of the mature plants were: 25(27)-dehydrochondrillasterol, 24β-ethyl-25(27)-dehydrolathosterol, avenasterol, spinasterol, 22-dihydrospinasterol and 24ξ-methyllathosterol. Based on the changes which occurred in the relative amounts of the Δ⁷-sterols, it did not appear that the Δ⁵-components were being converted to their Δ⁷-analogs. A portion of this work was presented at the meeting of the American Oil Chemists' Society in May, 1985 in Philadelphia.     

Vinyl acetate monomer—a pilot plant study

The kinetics of the reaction of acetic acid and acetylene over zinc acetate-activated carbon catalyst was investigated over a wide range of process variables in a pilot reactor. Although various catalytic reaction mechanisms were postulated, the rate of reaction was most satisfactorily correlated by a mechanism of surface reaction between charged adsorbed acetic acid and acetylene, which assumes that the rate controlling step was the irreversible charged adsorption of acetylene and acetic acid.     

Development of a simple low-cost solar simulator for indoor collector testing

Indoor test methods for solar collectors are widely accepted and recommended by ASHRAE. The development of a solar simulator for indoor testing and the certification procedure for photo-thermal solar devices is discussed in this paper. The system consists of 14 quartz halogen lamps and provides a testing area of about 1 × 1 m. The irradiance can be varied from 400 to 1500 W/m². This is achieved by varying the input power supplied to individual lamps. The radiation output characteristics of a single lamp have been studied. The distribution of intensity over the covered area of 1·20 × 1·20 m has been recorded using a precision Eppley pyranometer.A variety of collectors—evacuated tubular collectors and flat-plate collectors of both liquid and air heating types—has been tested under sufficiently stable insolation conditions. Results for a conventional solar air heater are presented together with suggestions for further improvements.     

Electricity generation from rice husk in Indian rice mills: Potential and financial viability

Rice husk generated as a by-product of rice processing is an important energy resource. The availability of this resource in India has been assessed and the technologies for exploitation of its energy potential in rice processing industry discussed. Nomographs have been developed for estimation of the husk required to meet the energy demand of parboiling, drying and milling operations. The unit cost of electricity using rice husk gasifier-based power generation systems has been calculated and its financial feasibility assessed in comparison with utility-supplied and diesel-generated electricity. With the cost and efficiency data assumed here, the unit cost of electricity produced by rice husk gasifier-dual fuel engine-generator system varies between Rs 2/kWh and Rs 7/kWh. (Note: 35 Rs approximates to $US 1.)     

The influence of packaging materials on RF performance

At frequencies beyond 1 GHz, every component of the IC package contributes to the RF performance, whether required or not. In this work, we study the effects of packaging materials namely, the substrate and the globtop/underfill material on RF performance. We have measured interconnects on two area-array CSPs, the ball grid array and the polymer stud grid array using IMEC’s MCM-D technology. The measurements on the package interconnect show that the losses in the package substrate material account for about 50% of the total losses at 1.8 GHz and this drops to less than 20% at 5.2 GHz. The losses due to impedance mismatch dominate the losses especially below 10 GHz and considerable improvement in performance cannot be obtained by using an improved/expensive substrate. The other study is about the influence of globtop/underfill materials on wirebonds (through 3D EM simulations) as well as on standard 50 Ω MCM-D transmission lines (through experiments). While a higher value of dielectric constant of the globtop/underfill material is better on wirebonds, the influence of loss tangent is felt only above values of 0.1. The influence of seven different globtop/undefill materials on 50 Ω transmission lines has been used to extract their dielectric constant and loss tangent values at 30 GHz. These results are very valuable since one can hardly find the properties of globtop/underfill materials beyond 1 GHz.     

Application of fiber optic sensors to fracture mechanics problems

An experimental study is conducted to show the application of fiber optic sensors to fracture mechanics problems. Mode I stress intensity factors are obtained using single mode optical fibers in single edge notched specimens fabricated from aluminium. A Mach–Zehnder interferometric set up is used during the experiments. The experimental results compare well with theoretical predictions.