3,123 research outputs found

    Constitutive behavior of as-cast A356

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    The constitutive behavior of aluminum alloy A356 in the as-cast condition has been characterized using compression tests performed over a wide range of deformation temperatures (30-500{\deg}C) and strain rates (\approx0.1-10 /s). This work is intended to support the development of process models for a wide range of conditions including those relevant to casting, forging and machining. The flow stress behavior as a function of temperature and strain rate has been fit to a modified Johnson-Cook and extended Ludwik-Hollomon expression. The data has also been assessed with both the strain-independent Kocks-Mecking and Zener-Hollomon frameworks. The predicted plastic flow stress for each expression are compared. The results indicate that the extended Ludwik-Hollomon is best suited to describe small strain conditions (stage III hardening), while the Kocks-Mecking is best employed for large strain (stage IV). At elevated temperatures, it was found that the Zener-Hollomon model provides the best prediction of flow stress.Comment: 34 pages, 12 figure

    Shoreland Buffer Module for GRANIT Data Mapper

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    The Complex Systems Research Center at the University of New Hampshire enhanced the GRANIT Data Mapper (http://mapper.granit.unh.edu) by incorporating data describing shoreline buffers in New Hampshire. The project supports an ongoing, comprehensive New Hampshire Estuaries Project (NHEP) outreach initiative that seeks to educate municipal decision-makers about the importance of stream buffers in preserving water quality in coastal New Hampshire. It complements these existing outreach efforts by allowing coastal managers, local land use boards, and the general public to readily visualize the spatial extent of current and/or proposed shoreline regulations in their community. The primary data source for the analysis was the high-resolution New Hampshire National Hydrography Dataset (NHHD). Using standard GIS tools, six concentric buffers incrementing in 50’ widths from 50’ to 300’ were generated around stream and shoreline features recorded in the NHHD. To provide the greatest flexibility to users, two data sets were generated at each buffer increment – one representing shorelines and streams classified as either perennial or intermittent, and the second comprising shorelines and only streams classified as perennial. The resulting buffers were merged with the GRANIT surface water data, and acreage by town and subwatershed was calculated for each buffer category. The shoreline buffer data sets were added to the water resources theme of the Data Mapper, thereby providing the public with the ability to view buffers of varying widths in the context of other data layers (including aerial imagery) available through the viewing tool. The associated acreage data tables were added to the water resources theme tool tab. Findings indicated that aggregated at the HUC-12 level, almost 24,000 acres within the Coastal Basin were covered by 50’ buffers when perennial and intermittent streams as well as shorelines were buffered, with over 133,000 acres covered by 300’ buffers. When only perennial streams and shorelines were considered eligible for buffering, the totals declined to just under 17,000 acres (50’ buffers) and over 96,000 acres (300’ buffers)

    Spectroradiometric calibration of the thematic mapper and multispectral scanner system

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    The results obtained for the absolute calibration of TM bands 2, 3, and 4 are presented. The results are based on TM image data collected simultaneously with ground and atmospheric data at White Sands, New Mexico. Also discussed are the results of a moments analysis to determine the equivalent bandpasses, effective central wavelengths and normalized responses of the TM and MSS spectral bands; the calibration of the BaSO, plate used at White Sands; and future plans

    Impact of Deficit Irrigation (DI) and Root-Zone Drying Irrigation Technique (PRD) under Different Nitrogen Rates on Radiation Use Efficiency for Potato (Solanum Tuberosum L.) in Semi-arid Conditions (II)

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    The study was carried out at the Technical Center of Potato and Artichoke CTPTA located in the lower valley of Medjerda river of Tunisia during the season of 2017. The purpose was to estimate the impact of deficit irrigation (DI) and the root-zone drying irrigation technique (PRD) under different nitrogen rates on photo synthetically active radiation absorbed and radiation use efficiency for Potato (Solanum Tuberosum L. VS. Spunta). Three water treatments (T1= 100% ETC, T2 = DI = 75% ETC and T3 = PRD50) and three nitrogen rates (F1 = N150: 150 kg N ha-1, F2 = N75: 75kg N ha-1, F3 = N0: 0kg N ha-1) were applied since the tuber initiation (55 days after planting) to maturity (100 days after planting). The deficit irrigation T2 has no effect on PARabs. Besides, the PRD50 has led to a reduction in PARabs. This decrease compare to T1 was equal to (8.9; 9.9 and 7.9%) respectively for the three treatments (F1; F2 and F3). The nitrogen deficit affects negatively the PARabs. An improvement of 13.2%, 11.2% and 12.2% of the F1 compared to the F3, respectively for the three water treatments (T1, T2 and T3). The T2 has no effect on RUE TDM. Conversely, the PRD50 has led to a reduction in RUE TDM. This decline referee against T1 was equal to (12.7; 17.4 and 21.5%) respectively for the three treatments (F1; F2 and F3). For RUEGY statistical analysis showed significant (P < 0.05) difference between the three irrigation treatments (T0, T1 and T2) for the three nitrogen treatments (F1; F2 and F3). The T2 and the PRD50 has led to a reduction in RUE GY. This decrease judge against T1 respectively for the two treatments (F2 and F3) was equal to (14.9 and 21.5%) and (19.6 and 31.2%)

    Trigonometric Parallax of W51 Main/South

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    We report measurement of the trigonometric parallax of W51 Main/South using the Very Long Baseline Array (VLBA). We measure a value of 0.185 +/- 0.010 mas, corresponding to a distance of 5.41 (+0.31/-0.28) kpc. W51 Main/South is a well-known massive star-forming region near the tangent point of the Sagittarius spiral arm of the Milky Way. Our distance to W51 yields an estimate of the distance to the Galactic center of Ro = 8.3 +/- 0.46 (statistical) +/- 1.0 (systematic) kpc by simple geometry. Combining the parallax and proper motion measurements for W51, we obtained the full-space motion of this massive star forming region. We find W51 is in a nearly circular orbit about the Galactic center. The H2O masers used for our parallax measurements trace four powerful bipolar outflows within a 0.4 pc size region, some of which are associated with dusty molecular hot cores and/or hyper- or ultra-compact HII regions.Comment: Accepted to ApJ; 32 pages; 6 tables; 5 figure

    Financing the Response to AIDS in Low- and Middle-Income Countries: International Assistance From the G8, European Commission and Other Donor Governments, 2007

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    Summarizes 2007 data on international AIDS assistance for low- and middle-income nations provided by donor governments. Presents trends by donor country, by funding channel, on aid as percentages of GDP, and on the gap between needs and resources

    Sizing-Up Connecticut’s Public Sector

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    Is non-federal government in Connecticut too large? Many think so and are happy to see state and local governments scaling back to balance their budgets in the face of a major recession and a drop in tax collections. But is government here as big as the critics contend? And, if so, is this strategically the right time to rein in public spending?

    Effect of Dietary Short and Medium Chain Fatty Acids in Murine Lethal Sepsis Model

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    Sepsis is defined as the presence of an infection in combination with systemic inflammation in a host. One of the detrimental results of sepsis is multiple organ failure which eventually leads to death. Lipopolysaccharide (LPS), an endotoxin that can be found on the outer surface of gram-negative bacteria, can be used as a model for sepsis. LPS present in the circulatory system of hosts can induce symptoms that are seen in patients during septicemia. Previous studies have suggested that including milk fat in a diet may protect against a lethal dosage of LPS in rodents. Milk fat has a unique fatty acid composition in which approximately 20-30% is made up of short and medium chain fatty acids. Interestingly, studies have also indicated that medium chain triglyceride (MCT) oil can also have a protective effect against LPS induced inflammation. The objective of this research was to determine if these dietary fatty acids, would have any effect against inflammation that is induced by LPS using an animal model
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