1,719 research outputs found

    Completion of evaluation of manufacturing processes for B/Al composites containing 0.2mm diameter boron fibers

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    Four fabricators produced a total of 54 B/1100 Al, B/6061 Al, and B/2024 Al panels for evaluation. The 8 ply unidirectional, 45 to 50 volume percent, panels were made using 0.20 mm diameter boron fibers which were obtained from a single supplier. Hot press consolidation was carried out in vacuum except for one set of dry woven tape panels which were hot pressed in air. A single testing contractor conducted nondestructive inspection, metallography, fractography and mechanical property tests. The mechanical property tests included 21 and 260 C tensile tests and 21 C shear tests. Panel quality, as measured by nondestructive evaluation, was generally good as were the 21 C tensile properties. The panels hot pressed in air delaminated in the shear tests. Shear strength values were lower in these panels. But tensile strengths were not affected by the delaminations because of the relation between the tensile loading direction and the delaminations. Composite tensile strength was found to be proportional to the volume percent boron and the aluminum matrix rather than to the tape used or fabrication technique. Suitability of these composites for 260 C service was confirmed by tensile tests

    The Impact of Auctions on Residential Sales Prices in New Zealand

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    The use of an auction to sell residential real estate in the United States is often associated with distressed sales such as foreclosure, bankruptcy or estate settlement. In other areas of the world, auctions are more commonly used and viewed as a viable, preferred method of selling a house. This article uses hedonic pricing methodology to compare the sale prices of houses in Christchurch, New Zealand sold at auction with those sold by private treaty. The results indicate that in some cases auctions can result in premium sale prices. In none of the cases studied did auctions result in lower prices than private-treaty sales.

    Pine straw yields and economic benefits when added to traditional wood products in loblolly, longleaf and slash pine stands

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    Paper presented at the 12th North American Agroforesty Conference, which was held June 4-9, 2011 in Athens, Georgia.In Ashton, S. F., S.W. Workman, W.G. Hubbard and D.J. Moorhead, eds. Agroforestry: A Profitable Land Use. Proceedings, 12th North American Agroforestry Conference, Athens, GA, June 4-9, 2011.Many forest landowners have the opportunity to manage their loblolly, longleaf and slash pine stands for pine straw (fresh undecomposed needles; the litter layer) for additional revenues. Pine straw is used primarily as mulch in landscaping and has grown in revenues paid to landowners from 15.5millionin1999to15.5 million in 1999 to 81 million in 2009 in Georgia. Pine straw is typically sold by the acre or by the bale. Selling pine straw by the acre is advantageous for absentee landowners. Selling pine straw by the bale can generate more annual income but bale counts need to be accurate and bale size must be clearly defined. Recent (2005-09) per acre revenues range from 50to50 to 125/year. Rectangular (13x13x28 inches) bale prices range from 0.25to0.25 to 0.40 for loblolly, 0.50to0.50 to 1.25 for longleaf, and 0.50to0.50 to 0.65 for slash pine in Georgia. Per rake yields from loblolly stands tend to be 15 to 30% greater (150 to 425 bales/acre) than slash (120 to 375 bales/acre) and longleaf pine (100 to 350 bales/acre). Pine straw raking starts at canopy closure continuing to the first thinning, generating from 300/acretoover300/acre to over 1000/acre in new income.E. David Dickens (1), David J. Moorhead (1), Charles T. Bargeron (1),and Bryan C. McElvany (2) ; 1. Warnell School of Forestry & Natural Resources. 2. College of Agriculture & Environmental Sciences, The University of Georgia, Statesboro, Tifton, and Soperton, GA.Includes bibliographical references

    Forest Resources Digital Information System

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    Forestry Images, the digitized documented forest health image archive, was developed with the aim to gather, create, maintain, and distribute digital information as tools to enhance and complement information exchange and educational activities. The Forestry Images System exists under the umbrella of Bugwood Network (Bargeron, Douce, & Moorhead, 2000). The increased volume of images and its usage statistics required major changes to enhance the system access, better content management, and security. The enhanced system is standard compliant based on recommendations from the World Wide Web Consortium (W3C) and the U.S. government Section 508

    Small Mammal Activity Alters Plant Community Composition and Microbial Activity in an Old-Field Ecosystem

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    Herbivores modify their environment by consuming plant biomass and redistributing materials across the landscape. While small mammalian herbivores, such as rodents, are typically inconspicuous, their impacts on plant community structure and chemistry can be large. We used a small mammal exclosure experiment to explore whether rodents in a southeastern old field directly altered the above ground plant species composition and chemistry, and indirectly altered the below ground soil community composition and activity. In general, when rodents were excluded, C3 graminoids increased in cover and biomass, contributing toward a shift in plant species composition relative to plots where rodents were present. The plant community chemistry also shifted; plant fiber concentration and carbon : nitrogen were higher, whereas plant nitrogen concentration was lower in exclosure plots relative to access plots. While microbial community enzyme activity increased when rodents were excluded, no significant changes in the fungal : bacterial or potential nitrogen mineralization occurred between treatments. Our results show that rodents can rapidly influence aboveground plant community composition and chemistry, but their influence on below ground processes may require plant inputs to the soil to accumulate over longer periods of time

    Pilot Trials of STAR Target to Range Glycemic Control

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    ESICM 2011 programme is available in files INTRODUCTION. Tight glycemic control (TGC) has shown benefits in cardiac surgery ICU patients. STAR (Stochastic TARgeted) is a flexible, model-based TGC protocol accounting for patient variability with a stochastically derived maximum 5% risk of blood glucose (BG) below 90 mg/dL. OBJECTIVES. To assess the safety, efficacy and clinical workload of the STAR TGC controller in pilot trials

    Hyperphosphatemia in chronic kidney disease exacerbates atherosclerosis via a mannosidases-mediated complex-type conversion of SCAP N-glycans

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    Blood phosphate levels are linked to atherosclerotic cardiovascular disease in patients with chronic kidney disease (CKD), but the molecular mechanisms remain unclear. Emerging studies indicate an involvement of hyperphosphatemia in CKD accelerated atherogenesis through disturbed cholesterol homeostasis. Here, we investigated a potential atherogenic role of high phosphate concentrations acting through aberrant activation of sterol regulatory element-binding protein (SREBP) and cleavage-activating protein (SCAP)-SREBP2 signaling in patients with CKD, hyperphosphatemic apolipoprotein E (ApoE) knockout mice, and cultured vascular smooth muscle cells. Hyperphosphatemia correlated positively with increased atherosclerotic cardiovascular disease risk in Chinese patients with CKD and severe atheromatous lesions in the aortas of ApoE knockout mice. Mice arteries had elevated SCAP levels with aberrantly activated SCAP-SREBP2 signaling. Excess phosphate in vitro raised the activity of α-mannosidase, resulting in delayed SCAP degradation through promoting complex-type conversion of SCAP N-glycans. The retention of SCAP enhanced transactivation of SREBP2 and expression of 3-hydroxy-3-methyl-glutaryl coenzyme A reductase, boosting intracellular cholesterol synthesis. Elevated α-mannosidase II activity was also observed in the aortas of ApoE knockout mice and the radial arteries of patients with uremia and hyperphosphatemia. High phosphate concentration in vitro elevated α-mannosidase II activity in the Golgi, enhanced complex-type conversion of SCAP N-glycans, thereby upregulating intracellular cholesterol synthesis. Thus, our studies explain how hyperphosphatemia independently accelerates atherosclerosis in CKD
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