Finite element modelling of cold formed stainless steel columns

This paper describes the results obtained from a finite element investigation into the load capacity of column members of lipped channel cross-section, cold formed from Type 304 stainless steel, subjected to concentric and eccentric compression loading. The main aims of this investigation were to determine the effects which the non-linearity of the stress-strain behaviour of the material would have on the column behaviour under concentric or eccentric loading. Stress-strain curves derived from tests and design codes are incorporated into non-linear finite element analyses of eccentrically loaded columns and the results obtained are compared with those obtained on the basis of experiments on stainless steel channel columns with the same properties and dimensions. Comparisons of the finite element results and the test results are also made with existing design specifications and conclusions are drawn on the basis of the comparisons

The Social Wasps (Hymenoptera: Vespidae) of Indiana

An updated taxonomic treatment of the social wasps (Hymenoptera: Vespidae) of Indiana is made. Illustrated identification keys are provided for species of Polistes, Vespa, Vespula, and Dolichovespula. New distributional records and biological notes are provided for each species

Swarm shape manipulation through connection control

The control of a large swarm of distributed agents is a well known challenge within the study of unmanned autonomous systems. However, it also presents many new opportunities. The advantages of operating a swarm through distributed means has been assessed in the literature for efficiency from both operational and economical aspects; practically as the number of agents increases, distributed control is favoured over centralised control, as it can reduce agent computational costs and increase robustness on the swarm. Distributed architectures, however, can present the drawback of requiring knowledge of the whole swarm state, therefore limiting the scalability of the swarm. In this paper a strategy is presented to address the challenges of distributed architectures, changing the way in which the swarm shape is controlled and providing a step towards verifiable swarm behaviour, achieving new configurations, while saving communication and computation resources. Instead of applying change at agent level (e.g. modify its guidance law), the sensing of the agents is addressed to a portion of agents, differentially driving their behaviour. This strategy is applied for swarms controlled by artificial potential functions which would ordinarily require global knowledge and all-to-all interactions. Limiting the agents' knowledge is proposed for the first time in this work as a methodology rather than obstacle to obtain desired swarm behaviour

Agricultural Contracting Update: Contracts in 2008

Marketing and production contracts covered 39 percent of the value of U.S. agricultural production in 2008, up from 36 percent in 2001, and a substantial increase over 28 percent in 1991 and 11 percent in 1969. However, aggregate contract use has stabilized in recent years and no longer suggests a strong trend. Contracts between farmers and their buyers are reached prior to harvest (or before the completion stage for livestock)and govern the terms under which products are transferred from the farm. Contracts are far more likely to be used on large farms than on small farms, and they form one element in a package of risk management tools available to farmers. Production contracts are used widely in livestock production, while marketing contracts are important to the production of many crops.Production contracts, marketing contracts, farm structure, farm size, farm income, contracting, Agricultural Resource Management Survey, ARMS, risk analysis, Agribusiness, Farm Management, Livestock Production/Industries, Risk and Uncertainty,

Agricultural Contracting Update: Contracts in 2003

Marketing and production contracts covered 39 percent of the value of U.S. agricultural production in 2003, up from 36 percent in 2001 and a substantial increase over estimated values of 28 percent for 1991 and 11 percent in 1969. Large farms are far more likely to contract than small farms; in fact, contracts cover over half of the value of production from farms with at least $1 million in sales. Although use of both production and marketing contracts has grown over time, growth is more rapid for production contracts, which are largely used for livestock.contracts, contracting, marketing contracts, production contracts, vertical integration, vertical coordination, market structure, risk analysis, price signals, Industrial Organization, Marketing,

Applying inspection to object-oriented software

The benefits of the object-oriented paradigmare widely cited. At the same time, inspection is deemed to be the most cost-effective means of detecting defects in software products. Why then, is there no published experience, let alone quantitative data, on the application of inspection to object-oriented systems? We describe the facilities of the object-oriented paradigm and the issues that these raise when inspecting object-oriented code. Several problems are caused by the disparity between the static code structure and its dynamic runtime behaviour. The large number of small methods in object-oriented systems can also cause problems. We then go on to describe three areas which may help mitigate problems found. Firstly, the use of various programming methods may assist in making object-oriented code easier to inspect. Secondly, improved program documentation can help the inspector understand the code which is under inspection. Finally, tool support can help the inspector to analyse the dynamic behaviour of the code. We conclude that while both the object-oriented paradigm and inspection provide excellent benefits on their own, combining the two may be a difficult exercise, requiring extensive support if it is to be successful

Numerical Tests of the Chiral Luttinger Liquid Theory for Fractional Hall Edges

We report on microscopic numerical studies which support the chiral Luttinger liquid theory of the fractional Hall edge proposed by Wen. Our calculations are based in part on newly proposed and accurate many-body trial wavefunctions for the low-energy edge excitations of fractional incompressible states.Comment: 12 pages + 1 figure, Revte

TRACING THE EFFECTS OF AGRICULTURAL COMMODITY PRICES ON FOOD PROCESSING COSTS

Although food processing sector production is inherently linked to the availability and prices of agricultural materials (MA), this link appears to be weakening due to adaptations in input costs, technology, and food consumption patterns. This study assesses the roles of these changes on food processors costs and output prices, with a focus on the demand for primary agricultural commodities. Our analysis of the 4-digit U.S. food processing industries for 1972-1992 is based on a cost-function framework, augmented by a profit maximization specification of output pricing, and a virtual price representation for agricultural materials and capital. We find that falling virtual prices of MA and input substitution have provided a stimulus for MA demand. However, scale effects have been MA-saving relative to intermediate food products, and disembodied technical change has strongly contributed to declining primary agricultural materials demand relative to most other inputs.Demand and Price Analysis, Industrial Organization,