The GAO natural gas supply model

This paper presents a small, annual model of natural gas supply used for policy analysis by the US General Accounting Office. The model incorporates a realistically complex lag structure and complex dynamics while maintaining a simple theoretical framework and manageable size. It simulates the historical record very well and is employed in this paper to generate three scenarios concerning gas supply from 1982–1990 under alternative price control policies.     

The effect of age of acquisition on speed and accuracy of naming famous faces

Three experiments examined whether famous faces would be affected by the age at which knowledge of the face was first acquired (AoA). Using a multiple regression design, Experiment 1 showed that rated familiarity and AoA were significant predictors of the time required to name pictures of celebrities' faces and the accuracy of producing their names. Experiment 2 replicated an effect of AoA using a factorial design in which other attributes of the celebrities were matched. In both Experiments 1 and 2, several ratings had been collected from participants before naming latency data were collected. Experiment 3 investigated the accuracy and latency of naming celebrities without any prior exposure to the stimuli. An advantage for naming early acquired celebrities was observed even on the first presentation. The participants named the same celebrities in three subsequent presentations of the stimuli. The effect of AoA was not significant on the fourth presentation. The implications of these results for models of face naming and directions for future research are discussed.     

A Study on the Reuse of Plastic Concrete Using Extended Set-Retarding Admixtures

The disposal of ready mixed concrete truck wash water and returned plastic concrete is a growing concern for the ready mixed concrete industry. Recently, extended set-retarding admixtures, or stabilizers, which slow or stop the hydration of portland cement have been introduced to the market. Treating truck wash-water or returned plastic concrete with stabilizing admixtures delays its setting and hardening, thereby facilitating the incorporation of these typically wasted materials in subsequent concrete batches. In a statistically designed experiment, the properties of blended concrete containing stabilized plastic concrete were evaluated. The variables in the study included (1) concrete age when stabilized, (2) stabilizer dosage, (3) holding period of the treated (stabilized) concrete prior to blending with fresh ingredients, and (4) amount of treated concrete in the blended batch. The setting time, strength, and drying shrinkage of the blended concretes were evaluated.For the conditions tested, batching 5 % treated concrete with fresh material did not have a significant effect on the setting time, strength, or drying shrinkage of the resulting blended concrete. Batching 50 % treated concrete with fresh materials had a significant effect on the setting characteristics of the blended cocnrete, which in turn affected the water demand to maintain slump. The data suggests that for a known set of conditions, the stabilizer dosage can be optimized within a relatively narrow range to produce desired setting characteristics. The strength and drying shrinkage of the blended concretes were essentially a function of the water content at different sampling ages and the relationship followed the general trend of control concrete.     

1,5,7-Trioxaspiro[5.5]undecane,a pheromone analog with high biological activity for the olive fruit fly,Dacus oleae

l,5,7-Trioxaspiro[5.5]undecane, an analog of the major sex pheromone (olean) of the olive fruit fly, was synthesized via two different routes and tested for biological activity under laboratory and field conditions. In laboratory tests, its activity was comparable to that of olean, especially when a stabilizer or a high concentration was used. In field tests, its activity reached the level of olean only when a stabilizer and an open-type dispenser, which allows high rates of evaporation, were used. The residual activity of the analog dispensers did not exceed two weeks both under laboratory and field conditions compared to over four months for olean.     

Jack Minker — A profile

This introduction provides a brief synopsis of Jack Minker's career. It discusses his contributions as a teacher, a researcher, as one who has served the computer science and logic programming communities, as an individual deeply committed to human rights, and as a person.     

Recent Testing Experience in a Large Motor Test Facility

New test facilities and testing capabilities are becoming increasingly important to verify the compliance of manufactured product to user needs. A discussion of the need for testing as well as the types and implications of various test methods is presented. A new facility is described and its ability to meet today's performance testing requirements is examined.     

Thermodynamics of carbon in austenite and Fe-Mo austenite

A Cahn Electrobalance has been used to determine directly and very accurately the carbon content of iron, iron-0.48 wt pct molybdenum and iron-1.16 wt pct molybdenum specimens which were equilibrated with a series of methane-hydrogen gas mixtures of constant composition. The equilibria investigated involved the austenite phases of the alloys at 783, 813 and 848‡C. The experimental results permit direct calculation of the activities of carbon in the samples, relative to graphite as unity, and of the enthalpy and entropy of solution of carbon. The results are compared with the experimental measurements of a number of other investigators. The results are in excellent agreement with those of Smith and Schenck and Kaiser for the Fe-C system at 800‡C, and indicate -H _C ^/M values of 9700 ± 500 cal/mole for pure Fe, 10,030 ± 500 cal/mole for an Fe-0.48 wt pct Mo alloy, and 10,150 ± 500 cal/mole for an Fe-1.16 wt pct Mo alloy. The effect of molybdenum in austenite is to decrease the activity coefficient of carbon in austenite.