Use of cascade reduction potential for selective precipitation of Au,Cu, and Pb in hydrochloric acid solution

Optimization of reduction potential for electroseparation was studied for the recovery of gold, copper, and lead from acidic solution. A linear sweep voltammetric method enabled us to determine characteristic reduction potentials for each metal and the kinetics of the metal deposition indicated by current-voltage curves. In order to precipitate the metal species sequentially, reduction potentials were examined for the individual and mixed solutions of Au(III), Cu(II), and Pb(II). The three metals were reasonably well isolated from the mixed solutions such as Cu(II)/ Pb(II) and Au(III)/Cu(II)/Pb(II) in the order of the corresponding reduction potentials, in particular, the mass transfer controlled reduction potentials, obtained from linear sweep voltammetry (LSV) measurement.     

A fast method to study the secretory activity of neuroendocrine cells at the ultrastructural level

Cryo field emission scanning electron microscopy (cryo-FE-SEM) is a versatile technique that allows the investigation of the three-dimensional organization of cells at the ultrastructural level over a wide range of magnifications. Unfortunately, cryopreparation of the specimens for this technique remains cumbersome, in particular because ice crystal formation must be prevented during freezing. Here we report that a light prefixation with glutaraldehyde and incubation in glycerol as cryoprotectant or a high-pressure freezing approach are both excellent procedures for cryopreparation of animal cells to be used in combination with cryo-FE-SEM. Using the proopiomelanocortin-producing intermediate pituitary melanotrope cells of Xenopus laevis as a physiologically inducible neuroendocrine system, we compared the ultrastructural characteristics of inactive and hyperactive neuroendocrine cells. The overall quality of the ultrastructural images was comparable for the two cryopreparation procedures, although some fine structures were better conserved using high-pressure freezing. Melanotrope cells in a secretory inactive state contained numerous storage granules and a poorly developed endoplasmic reticulum (ER), while large amounts of rough ER were present in hyperactive cells. Thus, the cryo-FE-SEM approach described here allows a fast ultrastructural study on the secretory activity of neuroendocrine cells.     

Some Notes on Stability Problems of Probabilistic Automata

Abstract

The behavior of a probabilistic automaton is essentially characterized by products of matrices selected from a given finite set of stochastic matrices. It is of interest to know under what conditions these matrix products are stable against perturbations of the entries in the matrices.     

The Capabilities of Some Species of Artificial Organisms

Abstract

A species of artificial organism in which individuals consist of freely interacting elementary components enclosed in an expandible envelope is described. Some organisms of this species are shown to be universal instruction-obeying mechanisms. Several procedures by which such artificial organisms might reproduce are presented and discussed.     

A Note on Maxwell's Demon and Universal Computation

Abstract

An analogy between a Maxwellian Demon capable of regulating the passage of particles between two chambers and a Turing machine capable of manipulating a tape and its symbols, is made explicit. It is shown that a slightly modified Maxwell's Demon can simulate a Universal Turing Machine.     

Design of linear multivariable continuous-time tracking systems incorporating error-actuated controllers

In this paper, the controllability results of Porter and Bradshaw (1974) are applied to the dosign of linear multivariable continuous-time tracking systems incorporating plants with inaccessible states for which appropriate error-actuated controllers exist. The design method is illustrated by the presentation of the results of computer simulation studies     

Shift Register Graphs and Permutation/Reset Automata

Abstract

This note completes the author's study of embedding of cascade products of permutation or reset automata in so-called shift register graphs.     

On the Properties of Fuzzy Switching Functions

Abstract

A strictly binary approach to the treatment of switching circuits today is not always adequate to describe systems in the real world. This approach is partly due, to the relative simplicity of designing binary switching systems, and to the fact that basic switching modules in common use are two-positional. Consequently, every variable in Boolean logic is assumed to be two-valued. However, because of real-world constraints, the attributes of system variables are often ambiguously defined. In other words, quite often variables might have values other than falsehood and truth. Cases with such attributes arise, for example in artifical intelligence and related subjects. Ever since Zadeh introduced the idea of fuzzy set theory [11 by utilizing the concept of membership grade, a number of authors have been concerned with the analysis and applications of fuzzy models. Especially, the relation of fuzzy to switching systems have been discussed in [2]–[12] and by other researchers in relation to other topics.

In this paper we are concerned with the study of fuzzy switching functions and their properties. Special attention is devoted to their minimization, enumeration, and their application to Boolean static hazard detection.     

Automating the factory: theory versus practice

Considerable attention has been given to the problems associated with acquiring and implementing many of the advanced manufacturing technologies currently available to firms. Much of the information being published, however, is based on individual experiences under conditions that are frequently not reported, as is common in the trade journals and public media. Fifteen such generally-accepted ‘postulates’ for managing factory automation are identified here and analysed in terms of five in-depth case studies involving advanced manufacturing systems. In a few cases, the postulates are rejected. In some cases they are qualified, and in many cases they are reinforced with substantially more detail.