Microstructural changes in Beta-silicon nitride grains upon crystallizing the grain-boundary glass

Crystallizing the grain boundary glass of a liquid phase sintered Si3N4 ceramic for 2 h or less at 1500 C led to formation of gamma Y2Si2O7. After 5 h at 1500 C, the gamma Y2Si2O7 had transformed to beta Y2Si2O7 with a concurrent dramatic increase in dislocation density within beta Si3N4 grains. Reasons for the increased dislocation density is discussed. Annealing for 20 h at 1500 C reduced dislocation densities to the levels found in as-sintered materials

Agro-terrorism and the Grain Handling Systems in Canada and the United States

The grain handling sector in Canada and the United States is vital to agriculture and trade. In a typical year on the Canadian prairies, about 140,000 producers deliver some 20 to 30 mmt of grain for export to primary elevators. In the United States, about 2.1 million producers deliver about 300 mmt of grain to primary elevators. Canadian grain is moved to export position using more than 400,000 hopper cars and marine containers, where about 1,200 ships per year are loaded. In the United States, about 1.08 million rail carloads of grain are originated per year, and about 23 mmt of grain are shipped on barges per year. These U.S. figures are in addition to trucks, which, more so than in Canada, are also used to deliver grain to primary processors and to terminal and export markets. The volume of grain trade gives rise to concern about risks of terrorism in the sector.(1) From a security perspective, the grain, pulse and oilseed supply chain is noteworthy because much of it is characterized by relatively long-term, insecure, bulky storage (particularly on farms) along with numerous modal and inter-modal product transfers. These factors suggest there are many places where chemical or biological contaminants could be introduced into this supply chain. From the perspective of the United States, security throughout the Canadian system as well as the U.S. system is a concern, since cross-border traffic in these products is significant, with an average of about six million tonnes of grain products alone imported into the U.S. each year (USDA-FAS, 2003). Numerous interventions to enhance food safety and mitigate the risk of terrorism have been adopted or are in the process of being developed. Some of these are private initiatives and voluntary, as a component of firm-level security processes. Others are being adopted in response to legislated initiatives. The stakes are large, and there are likely to be substantial differences in costs and effectiveness of different approaches.Agricultural and Food Policy, Food Consumption/Nutrition/Food Safety,

Food Risks and Type I & II Errors

The IFAMR is published by (IFAMA) the International Food and Agribusiness Management Review. www.ifama.orgFood safety, food defense, error based disruption, control oriented supply networks, Agribusiness, Food Consumption/Nutrition/Food Safety, Food Security and Poverty, Risk and Uncertainty, Q130,

Composite transport wing technology development: Design development tests and advanced structural concepts

Numerous design concepts, materials, and manufacturing methods were investigated for the covers and spars of a transport box wing. Cover panels and spar segments were fabricated and tested to verify the structural integrity of design concepts and fabrication techniques. Compression tests on stiffened panels demonstrated the ability of graphite/epoxy wing upper cover designs to achieve a 35 percent weight savings compared to the aluminum baseline. The impact damage tolerance of the designs and materials used for these panels limits the allowable compression strain and therefore the maximum achievable weight savings. Bending and shear tests on various spar designs verified an average weight savings of 37 percent compared to the aluminum baseline. Impact damage to spar webs did not significantly degrade structural performance. Predictions of spar web shear instability correlated well with measured performance. The structural integrity of spars manufactured by filament winding equalled or exceeded those fabricated by hand lay-up. The information obtained will be applied to the design, fabrication, and test of a full-scale section of a wing box. When completed, the tests on the technology integration box beam will demonstrate the structural integrity of an advanced composite wing design which is 25 percent lighter than the metal baseline

Plasma and testicular testosterone levels, volume density and number of Leydig cells and spermatogenic efficiency of rabbits

Plasma and tissue testosterone concentrations were determined by radioimmunoassay in 12 eight-month-old sexually mature New Zealand White rabbits and evaluated for possible associations with spermatogenic efficiency as well as with volume density and number of Leydig cells. Testicular tissue was processed histologically and histometry was performed in order to quantify germ cells, Sertoli cells and Leydig cells. Spermatogenic efficiency, reported as the ratios among germ cells (spermatogonia, primary spermatocytes and round spermatids) and by the ratio of germ cells to Sertoli cells, was not associated with testosterone levels. However, Leydig cell parameters such as number of Leydig cells per gram of testis, total number of Leydig cells per testis and percent cell volume of Leydig cell nuclei were correlated significantly with testosterone levels. The statistically significant correlation (r = 0.82, P\u3c0.05) observed between testosterone levels and the number of Leydig cells per gram of testis suggests that, in the rabbit, the latter parameter can serve as a criterion for monitoring testosterone levels in this species under normal conditions

Whales, dolphins, and porpoises of the eastern North Pacific and adjacent Arctic waters: a guide to their identification

This is an identification guide for cetaceans (whales, dolphins, and porpoises), that was designed to assist laymen in identifying cetaceans encountered in eastern North Pacific and Arctic waters. It was intended for use by ongoing cetacean observer programs. This is a revision of an earlier guide with the same title published in 1972 by the Naval Undersa Center and the National Marine Fisheries Service. It includes sections on identifying cetaceans at sea as well as stranded animals on shore. Species accounts are divided by body size and presence or lack of a dorsal fin. Appendices include illustrations of tags on whales, dolphins, and porpoises, by Larry Hobbs; how to record data from observed cetaceans at sea and for stranded cetaceans; and a list of cetacean names in Japanese and Russian. (Document contains 245 pages - file takes considerable time to open

Effectiveness of learning and experimentation approaches for farmers as a community based strategy for banana xanthomonas wilt management

Banana Xanthomonas wilt (BXW) is a devastating disease for banana and enset in east, central and Horn of Africa since 1968. The disease has spread to all banana growing countries in the region in the last decade, causing yield losses of up to 80 to 100%. Several efforts have been undertaken to develop and implement technologies for BXW management and their effective deployment with varying successes. This paper presents a new participatory approach for managing BXW named Learning and Experimentation Approaches For Farmers (LEAFF) and describes how it was implemented, tested and evaluated among 220 farmers across two agroecological regions, central and South-western Uganda. Results showed that there was a general reduction in the number of infected plants, corresponding to 7% increase in productivity of banana among the LEAFF compared to the non LEAFF participating farmers. The findings suggested that scaling out LEAFF to different parts in the region can significantly contribute to effective and sustainable adoption of BXW management technologies, and in turn, can lead to improved productivity and smallholder farmers’ livelihoods