Spinarc gas tungsten arc torch holder

Semiautomatic welding torch enables operator to control arc length, torch angle, and spring tension when welding small diameter aluminum tubing. Tungsten is preset for the weld to make arc initiation easier and to eliminate searching for the joint through a dark welding lens

The finite element machine: An experiment in parallel processing

The finite element machine is a prototype computer designed to support parallel solutions to structural analysis problems. The hardware architecture and support software for the machine, initial solution algorithms and test applications, and preliminary results are described

Exchange and Specialisation as a Discovery Process

In this article we study the performance of an economy that can support specialisation if the participants develop and follow some system of exchange. We define a closed economy in which the participants must discover the ability to exchange, implement it, and ascertain what they are comparatively advantaged in producing. Many of our participants demonstrate the ability to find comparative advantage, capture gains from trade and effectively choose production that is consistent with the choices of others. We explore various treatments to provide insight into the conditions that foster the growth of specialisation and exchange within this weak institutional framework

Credit Cards as Lifestyle Facilitators

Credit cards are an increasingly essential technology, but they carry with them the paradoxical capacity to propel consumers along lifestyle trajectories of marketplace freedom or constraint. We analyze accounts provided by consumers, credit counselors, and participants in a credit counseling seminar in order to develop a differentiated theory of lifestyle facilitation through credit card practice. The skills and tastes expressed by credit card practice help distinguish between the lifestyles of those with higher cultural capital relative to those with lower cultural capital. Differences in lifestyle regulation practice are posited to originate in cultural discourses related to entitlement and frugality

Cold Acclimation Strategy Is Highly Variable among the Sunfishes (Centrarchidae)

We tested the hypothesis that the physiological strategy for acclimating to low body temperature is similar among closely related fish. Largemouth bass (Micropterus salmoides), green sunfish (Lepomis cyanellus), bluegill sunfish (Lepomis macrochirus), black crappie (Pomonix nigromaculatus), and white crappie (Pomonix annularis), all members of the family Centrarchidae, were acclimated to 5° and 25°C. Morphometric variables (total mass, total length, organ masses) and enzyme activities (hexokinase; lactate dehydrogenase; and cytochrome oxidase in heart, liver, and muscle) were measured in 5°C- and 25°C-acclimated fish at 5° and 25°C assay temperatures. Each species displayed a distinct physiological response to cold acclimation that differed among tissues. These data suggest that the response to cold acclimation is highly variable within families. Our findings are consistent with other studies suggesting that acclimation responses are labile and may evolve independently even among closely related species. Reprinted by permission of the publisher

Differential Charge Sensing and Charge Delocalization in a Tunable Double Quantum Dot

We report measurements of a tunable double quantum dot, operating in the quantum regime, with integrated local charge sensors. The spatial resolution of the sensors is sufficient to allow the charge distribution within the double dot system to be resolved at fixed total charge. We use this readout scheme to investigate charge delocalization as a function of temperature and strength of tunnel coupling, showing that local charge sensing allows an accurate determination of interdot tunnel coupling in the absence of transport.Comment: related papers at http://marcuslab.harvard.ed