A 0.9-V microcontroller for portable applications

A 0.9-1.6-V, 1-MHz, 8-b microcontroller based on the 68HC08 architecture is presented. In addition to standard digital microcontroller functions, the chip features RAM, ROM, phase-locked loop (PLL) clock synthesis, and liquid crystal displays (LCD) drive capabilities operating from the voltage supply range of a single AA or AAA battery. The design used a library of CMOS microcontroller building blocks, converted into a low-voltage technology using unilateral transistors. The design approach was to optimize the conversion strategy for each functional block and to provide new designs when the conversion was insufficient. The chip exceeded specifications with blocks showing full functionality down to 0.7 V     

Case Study: Managing IS Through Turbulent Times

Usually, when an organization faces a crisis situation, the IS department suffers cutbacks in staff and systems development projects without any consideration for the adverse effects these actions might have on the departments ability to contribute to the organization's bottom line. This case study examines how one company – Bethlehem Steel Corp-facing its own business decline carefully restructured its IS department to operate more efficiently on its own and become a stronger, more profitable contributor so that it could help Bethlehem Steel successfully compete in the global steel market.     

Sieverts law pressure exponent for hydrogen permeation through Pd-based membranes: Coupled influence of non-ideal diffusion and multicomponent external mass transfer

This paper focuses on the suitability of using a Sieverts-type empirical law to describe hydrogen permeation through Pd-based membranes in the presence of both concentration-dependent hydrogen transport through the selective layer – referred to as “non-ideal” behaviour – and external mass transfer resistance. In particular, the functionality of the pressure exponent with temperature, pressure and membrane thickness is provided, showing that the Sieverts-type empirical law can be used to incorporate the external mass transfer influence just up to a moderate external resistance. The explanation for this fact is recognised in the inadequacy of the Sieverts-type empirical law to describe the behaviour of the flux limited by external resistance for a sufficiently large permeation driving force. The methodology described in this paper is effective also when the permeation-determining steps cannot be established, helping researchers to a correct interpretation of permeation tests in the presence of severe mass transfer resistance.     

The storage of cottonseed

Summary Treatment of moist cottonseed with ammonia prior to storage has been shown to reduce self-heating of the seed and the rate of formation of free fatty acids during storage. The color of oils obtained by solvent extraction from ammonia-treated cottonseed is considerably lighter than that of oils obtained from untreated cottonseed.     

Meeting the IS Challenge: A Success Story

Facing large-scale economic, social, and technological upheaval, IS executives everywhere are beginning to see that the typical IS department sits on shaky ground. This column describes one IS executive's approach to establishing a solid IS management support system.     

Quantitative contribution of non-ideal permeability under diffusion-controlled hydrogen permeation through Pd-membranes

In this paper, a powerful and simple method to evaluate quantitatively the influence of the non-ideal contribution of the hydrogen permeation under diffusion control is provided. For this purpose, a Non-Ideality Index (α) is defined as the ratio of the non-ideal permeability term and the overall permeability, this leading to a direct quantification of the non-ideal effect in membrane.     

Modelling and simulation of hydrogen permeation through supported Pd-alloy membranes with a multicomponent approach

Hydrogen transport in Pd-based supported membranes was described by means of a model considering several elementary steps of the permeation process, improving what done by Ward and Dao [1999. Model of hydrogen permeation behavior in palladium membranes. Journal of Membrane Science 153 (2), 211-231] for self-supported membranes. The model includes the external mass transfer in the multicomponent gaseous phases on both sides of the membrane, described by the Stefan-Maxwell equations. The transport of the multicomponent mixture in the multilayered porous support was also considered and described by means of the dusty gas model, which takes into account Knudsen, Poiseuille and ordinary diffusion. The diffusion in the Pd-alloy layer is modeled by the irreversible thermodynamics theory, taking the hydrogen chemical potential as the driving force of the diffusion in the metallic bulk. The interfacial phenomena (adsorption, desorption, transition from Pd-based surface to Pd-based bulk and vice-versa) were described by the same expressions used by Ward and Dao (1999). Thicknesses of 1 and are considered for the Pd-alloy layer. The asymmetric support consists of five layers, each one characterized by a specific thickness and mean pore diameter. The model separates the permeation steps and consequently their influence, quantifying the relative resistances offered by each of them. Comparison with some experimental data in several conditions in the literature shows a good agreement. The developed tool is able to describe hydrogen transport through a supported Pd-based membrane, recognizing the rate-determining steps (e.g., diffusion in the metallic bulk or in the porous support) involved in the permeation.     

Spectral properties of linoleic and linolenic acids prepared by debromination

Summary Modified procedures are described for the preparation of linoleic and linolenic acids which remove and/or prevent the formation of conjugated acids. The importance of spectrophotometric measurements as a criterion of purity is emphasized. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.