Numerical simulation of ratcheting and fatigue behaviour of mitred pipe bends under in-plane bending and internal pressure

This paper investigates the ratcheting and fatigue behaviour of 90 degree single unreinforced mitred pipe bends subjected to a cyclic in-plane closing moment with a non-zero mean value and constant internal pressure. An experiment was conducted to induce ratcheting and low cycle failure of the mitred pipe bend. Material and structural response is considered both locally and globally using strain gauges at the locations of highest strain and also by measuring the displacement of the mitre end. These results along with the number of cycles to failure are compared with those produced from nonlinear finite element analysis. The predicted crosshead displacement from the multi linear model showed a good agreement with the test results. However, the finite element model failed to accurately replicate the strain level or trend from the tests, indicating the weakness of the material model used in simulating the cyclic hardening effect. It was also found that the FE models proposed were not able to model the final failure mode of the mitre due to the exclusion of crack simulation in the analysis, i.e. interaction between ratcheting and low cycle fatigue cracking was not considered in the idealised numerical model

Biology and Behavior of the Asian Needle Ant, \u3ci\u3e Brachyponera chinensis \u3c/i\u3e

Ants are among the most successful invasive organisms in the world. To curb the spread of invasive ants in non-native environments, their ecological, biological, and behavioral characteristics must be identified. The Asian needle ant, Brachyponera (= Pachycondyla ) chinensis (Emery) is an emerging invasive pest in urban areas and forests in the southeastern United States. However, general basic biological information on B. chinensis and subsequent management options are deficient. This work contributes to the standing biological information on B. chinensis by examining the seasonal life cycle, social nesting habits, and transport behaviors of B. chinensis colonies. To determine the seasonal life cycle of Asian needle ants, nests were collected monthly for ten months from infested locations in South Carolina. During the study 40 nests were collected and the number of workers, queens, male/female alates, eggs, larvae, and pupae was determined. The ants follow a seasonal cycle of production. Worker ant numbers are highest in May, August, and October while the majority of male and female reproductives are produced in July and August. Colonies also produce more males than reproductive females during the year. The number of workers and male ants found in a nest is positively correlated with the number of queens. To determine if Asian needle ants are polydomous, I investigated the spatial organization and aggression between B. chinensis nests. Spatial distribution of nests was determined in four B. chinensis infested locations. Monte Carlo tests for compete spatial randomness revealed that three nests followed a pattern of uniform distribution suggesting that the ants are not polydomous. However, nests in one of the plots did follow a clumped distribution. Furthermore, workers originating from the same experimental plot and separate locations did not display aggression in 3 x 3 nestmate recognition assays, suggesting that B. chinensis are a polydomous ant species In a laboratory study, the recruitment behaviors of B. chinensis ants during nest emigration were determined. Before recruitment to the new nest location began, B. chinensisants organized into three distinctive groups: queen-tending, brood-tending, and scouting. Once the new nest site was identified, scout ants began physically transporting nestmates into the new harborage via tandem carrying or adult transport. Transport rates increased in the first 30 minutes and did not change during the 30-55-minute time interval when brood was transported. However, the adult transport rate increased again after brood transport was completed and decreased after 90 minutes. Results presented in the current study contribute to the growing body of biological knowledge on invasive B. chinensis populations in the U.S. The information presented here are the first to address the colony attributes of this species. I identified adult transport as a recruiting method during emigration. Further the information presented here, highlight the life cycle and polydomous nature of B. chinensis and support the development of a seasonally based and area-wide management strategies for this nuisance ant species

Nutrient Analysis of South Dakota Swine Feeds

Current economical conditions-have forced swine producers to utilize available resources efficiently to reduce production cost. A major portion of the production cost in most swine enterprises may be attributed to obtaining, handling and processing feeds. Grains are utilized as a source of dietary energy and constitute a major portion of swine diets. Thus, the practice of evaluating all feed grains available in a given geographic area to determine the grains providing the most economical gains other than feeding only those grains raised by the individual producer is expected to increase. Producers must understand how grains differ in their nutritional and physical characteristics and have an appreciation for nutritional principles to utilize grains other than corn economically. The survey study reported herein was conducted to better understand the feed handling, mixing and nutritional practices used by South Dakota swine producers. From these results, more useful educational programs in swine nutrition management may be developed

Molds and Mycotoxins in Swine Diets

Molds (or fungus) are commonly found in the environment, with more than 200,000 species recognized at present. About 60 species of mold have been determined to be harmful to man and animals. The presence of molds in feed grains may result in problems and economic losses for swine producers. Molds utilize nutrients present in infected grains to lower the available energy, vitamin E and carotene levels in these grains. Certain groups of molds may produce chemical metabolites, called mycotoxins, that are detrimental to the growth and . reproductive function of swine, if ingested

Continuous path : the evolution of process control technologies in post-war Britain

Automation - the alliance of a series of advances in manufacturing technology with the academic discipline of cybernetics - was the centre of both popular and technical debate for a number of years in the mid-1950s. Alarmists predicted social disruption, economic hardship, and a massive de-skilling of the workforce; while technological positivists saw automation as an enabling technology that would introduce a new age of prosperity. At the same time as this debate was taking place, increasingly sophisticated control technologies based on digital electronics and the principle of feedback control were being developed and applied to industrial manufacturing systems. This thesis examines two stages in the evolution of process control technology: the numerical control of machine tools; and the development of the small computer, or minicomputer. In each case two key themes are explored: the notion of industrial failure; and the role of new technologies in Britain's industrial decline. In Britain, four projects were undertaken to develop point-to-point or continuous path automatic controllers for machine tools in the mid-1950s - three by electronics firms and one by a traditional machine tool manufacturer. However, although automation was dominating popular debate at the time, the anticipated market for numerically controlled systems failed to appear, and all of the early projects were abandoned. It is argued that while the electronics firms naively misdirected their limited marketing capabilities, the root of the problem was the traditional machine tool manufacturers' conservatism and their failure to embrace the new technology. A decade later, small computers based on new semiconductor technologies had emerged in the United States. Originally developed for roles in industrial automation, they soon began to compete at the low end of the mainframe computer market. Soon afterwards a number of British firms - electronic goods manufacturers, entrepreneurial start-ups, and even office machinery suppliers - began to develop minicomputers. The Wilson government saw computers as a central element of industrial modernisation, and thus a part of its solution to Britain's economic decline, so the Ministry of Technology was charged with the promotion of the British minicomputer industry. However, US-built systems proved more competitive, and by the mid-1970s they had come to dominate the market, with the few remaining British firms relegated as niche players. It is argued that government involvement in the minicomputer industry was ineffectual, and that the minicomputer manufacturers' organisational cultures played a major role in the failure of the British industry

Measuring Redshift-Space Distortions using Photometric Surveys

We outline how redshift-space distortions (RSD) can be measured from the angular correlation function w({\theta}), of galaxies selected from photometric surveys. The natural degeneracy between RSD and galaxy bias can be minimized by comparing results from bins with top-hat galaxy selection in redshift, and bins based on the radial position of galaxy pair centres. This comparison can also be used to test the accuracy of the photometric redshifts. The presence of RSD will be clearly detectable with the next generation of photometric redshift surveys. We show that the Dark Energy Survey (DES) will be able to measure f(z){\sigma}_8(z) to a 1{\sigma} accuracy of (17 {\times} b)%, using galaxies drawn from a single narrow redshift slice centered at z = 1. Here b is the linear bias, and f is the logarithmic rate of change of the linear growth rate with respect to the scale factor. Extending to measurements of w({\theta}) for a series of bins of width 0.02(1 + z) over 0.5 < z < 1.4 will measure {\gamma} to a 1{\sigma} accuracy of 25%, given the model f = {\Omega}_m(z)^{\gamma}, and assuming a linear bias model that evolves such that b = 0.5 + z (and fixing other cosmological parameters). The accuracy of our analytic predictions is confirmed using mock catalogs drawn from simulations conducted by the MICE collaboration.Comment: Accepted by MNRAS, revisions include fixing of typos and clarification of the tex