Studies in the carbothermic reduction of phosphogypsum

Phosphogypsum has been reduced in the solid state by active charcoal both in the presence and absence of catalysts. Kinetic data could be fitted to the modified volume reaction model. Mixed catalysts like potassium dichromate were found to enhance the reaction rate quite satisfactorily. This result could be fruitfully employed during reduction with industrial coke also.     

Protein digestibility of pigskin and bovine tendon in rats

The protein nutritional value of pigskins and bovine tendons, with collagen contents of 75 and 95% respectively, was evaluated using amino acid analyses and nitrogen balance experiments on rats. Pigskins contain somewhat higher amounts of tryptophan, meth-ionine, cystine and tyrosine than tendons. The amounts of several essential amino acids were low. The true digestibilities were for young (4 month old), unscalded pigskin 96.1%, old (5 year old), unscalded pigskin 92.5%, calf tendon 97.3% and cow tendon 92.4%. Small but statistically significant differences due to the animal age were observed. Insoluble collagen, extracted from bovine tendon, had a digestibility of 95.2%. Wet heat treatment of old pigskin and cow tendon samples at 74â°C for 30 min significantly increased the digestibilities to 96.3 and 97.3% respectively. The results indicate that prior denaturation of collagen, as obtained by, for example, heat treat-ment, is not necessary for the digestion of pigskin and tendon in rats.     

Psychology as an ambiguous attitude stimulus.

College freshmen and their parents applied each of 3 methods for assessing public image (a naturalistic approach, a listing of adjectives, and a Likert scale) to 6 professions. A rank ordering was obtained and ranks were compared across methods. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Use of an Azur-A–NTA system in a photogalvanic cell for solar energy conversion

Nitrilotriacetic acid (NTA) and Azur-A were used as the reductant and photosensitizer, respectively, for the photo-generation of electrical current. The photocurrent and photopotential generated by the cell were 60 μA and 362 mV, respectively. The effects of various parameters on the electrical output of the cell were also observed. The mechanism for the generation of photocurrent in this cell has been proposed. The maximum power obtained from this cell is 17.82 μW.     

Diffusion of toluene sulfonic acid in nylon film

The permeation of p-toluene sulfonic acid through nylon 66 film has been studied at different concentrations of sulfonic acid. The ordinary diffusion coefficient in the membrane was found to increase with increasing concentration in nylon, moderately at low concentration but very rapidly when approaching the Langmuir saturation concentration.     

Biochemical basis of insect resistance in Vigna unguiculata

The bruchid beetle Callosobruchus maculatus (F.) causes extensive damage to seeds of the cowpea, Vigna unguiculata (L.) (Walp.), when this important tropical foodstuff is stored. A variety of cowpea resistant to attack by this pest has been described. In the present work seeds of a number of cowpea varieties, including the resistant one, were tested for the presence of a physical resistance to C. maculatus, in terms of repulsion of oviposition or of failure of larvae to enter the seeds. No evidence to suggest the presence of a physical resistance was found. When seeds of cowpea varieties were tested for the presence of various antimetabolic secondary compounds, only inhibitory activity against trypsin and, to a much lesser extent, chymotrypsin, could be detected. The resistant variety of cowpea contained a significantly higher level of inhibitors, about twice as much as any other variety. A proteinase inhibitor active against trypsin was purified from cowpea varieties by affinity chromatography on trypsin-Sepharose. The purified inhibitor was shown to inhibit chyraotrypsin also, in such proportions as to account for chymotrypsin inhibition by seed extracts. The inhibitor was shown to consist of a number of isoinhibitors by gel electrophoresis and isoelectric focusing, but no qualitative differences in the inhibitor between varieties could be detected. The antimetabolic nature of the cowpea trypsin inhibitor was confirmed by insect feeding trials in which various protein fractions were added to a basic meal and the effect on larval survival noted. The albumin proteins of cowpea (containing the trypsin inhibitors) at a level of 10% were toxic to larvae of C. maculatus whereas the globulin fractions were not. Further, if cowpea trypsin inhibitor was removed from the albumin proteins they ceased to be toxic. When purified cowpea trypsin inhibitor was added to the basic meal it was shown that a level slightly less than that found in the resistant variety of cowpea caused complete mortality of larvae, whereas lower levels had lesser or no effect. It is concluded that this example of insect resistance in the cowpea is due to an elevated level of trypsin inhibitor.     

Recognition algorithms for the connection machine

This paper describes an object recognition algorithm both on a sequential machine and on a single instruction multiple data (SIMD) parallel processor such as the MIT connection machine. The problem, in the way it is presently formulated on a sequential machine, is essentially a propagation of constraints through a tree of possibilities in an attempt to prune the tree to a small number of leaves. The tree can become excessively large, however, and so implementations on massively parallel machines are sought in order to speed up the problem. Two fast parallel algorithms are described here, a static algorithm and a dynamic algorithm. The static algorithm reformulates the problem by assigning every leaf in the completely expanded unpruned tree to a separate processor in the connection machine. Then pruning is done in nearly constant time by broadcasting constraints to the entire SIMD array. This parallel version is shown to run three to four orders of magnitude faster than the sequential version. For large recognition problems which would exceed the capacity of the machine, a dynamic algorithm is described which performs a series of loading and pruning steps, dynamically allocating and deallocating processors through the use of the connection machine's global router communications mechanism.     

A framework for meta-level control in multi-agent systems

Sophisticated agents operating in open environments must make decisions that efficiently trade off the use of their limited resources between dynamic deliberative actions and domain actions. This is the meta-level control problem for agents operating in resource-bounded multi-agent environments. Control activities involve decisions on when to invoke and the amount to effort to put into scheduling and coordination of domain activities. The focus of this paper is how to make effective meta-level control decisions. We show that meta-level control with bounded computational overhead allows complex agents to solve problems more efficiently than current approaches in dynamic open multi-agent environments. The meta-level control approach that we present is based on the decision-theoretic use of an abstract representation of the agent state. This abstraction concisely captures critical information necessary for decision making while bounding the cost of meta-level control and is appropriate for use in automatically learning the meta-level control policies.