2,552 research outputs found

    Vacancy Reassessed

    Get PDF
    Since 1950, Philadelphia's population has been declining dramatically, by more than 30 percent. This rapid depopulation has led to the vacancy and abandonment of a large number of unmanaged residential lots and buildings. The future of Philadelphia rests on its ability to manage this decline, and in 1999, efforts were fragmented. This report highlights the barriers that many faced in trying to access vacant property and provides recommendations for a more strategic vision so that the city can create a significant and lasting impact

    Wear-Resistant Boride Nanocomposite coating Exhibits Low Friction

    Get PDF
    Many components experience sliding or rotating contact with other parts or with their environments. Their performance often degrades during service because their dimensions are altered by wear. Furthermore, the friction at the contact surface wastes energy. To mitigate these problems, hard coatings may be applied to contact surfaces to increase their wear resistance, and surfaces are often covered with a lubricant to reduce friction. At Ames National Laboratory, a nanocomposite boron-aluminum-magnesium ceramic alloy coating (AlMgB14 + TiB2) has been developed that provides a superhard, wear-resistant surface that also has an exceptionally low coefficient of friction. Tests show that these boride coatings offer a combination of wear resistance and low friction unmatched by other hard mate - rials (e.g., tungsten carbide, cubic boron nitride, or diamondlike carbon)

    Is there any Evidence for Regional Atmospheric 14C Offsets in the Southern Hemisphere?

    Get PDF
    Center for Accelerator Mass Spectrometry (CAMS) Tasmanian huon pine (Lagarostrobos franklinii) decadal measurements for the interval AD 745–855 suggest a mean interhemispheric radiocarbon offset (20 ± 5 yr), which is considerably lower than the previously reported mean interhemispheric offset for the last 2 millennia (44 ± 17 yr). However, comparable University of Waikato (Wk) New Zealand kauri (Agathis australis) measurements show significantly higher values (56 ± 6 yr), suggesting the possibility of a temporary geographic (intrahemispheric) offset between Tasmania, Australia, and Northland, New Zealand, during at least 1 common time interval. Here, we report 9 new Wk Tasmanian huon pine measurements from the decades showing the largest huon/kauri difference. We show statistically indistinguishable Wk huon and Wk kauri 14C ages, thus dispelling the suggestion of a 14C geographic offset between Tasmania and Northland

    The Willingness to Pay for Mortality Risk Reductions: A Comparison of the United States and Canada

    Get PDF
    We present results for two contingent valuation surveys conducted in Hamilton, Canada and the US to elicit WTP for mortality risk reductions. We find similar Value of Statistical Life estimates across the two studies, ranging from USD 930,000 to USD 4.8 million (2000 US dollars). WTP increases with risk reduction size, but varies little with respondent age: individuals aged over 70 years hold WTP values approximately one-third lower than other respondents. Respondent health status has limited effect on WTP. These results provide little or no evidence for adjusting VSL estimates used in policy analyses for the affected population’s age or health status.value of a statistical life, mortality risks, benefit-cost analysis

    Evidence for suppressed mid-Holocene northeastern Australian monsoon variability from coral luminescence

    Get PDF
    Summer monsoon rainfall in northeastern (NE) Australia exhibits substantial interannual variability resulting in highly variable river flows. The occurrence and magnitude of these seasonal river flows are reliably recorded in modern inshore corals as luminescent lines. Here we present reconstructed annual river flows for two ~120 year mid-Holocene windows based on luminescence measurements from five cores obtained from three separate coral colonies. We were able to cross-date the luminescence signatures in four cores from two of the colonies, providing confidence in the derived reconstruction. Present-day NE Australian rainfall and river flow are sensitive to El Niño–Southern Oscillation (ENSO) variability, with La Niña (El Niño) events typically associated with wetter (drier) monsoon seasons. Thus, our replicated and annually resolved coral records provide valuable insights into the northern Australian summer monsoon and ENSO variability at a key period (6 ka) when greenhouse gas levels and ice sheet cover were comparable to the preindustrial period but orbital forcing was different. Average modern and mid-Holocene growth characteristics were very similar, suggesting that sea surface temperatures off NE Australia at 6 kyr were also close to present values. The reconstructed river flow record suggests, however, that the mid-Holocene Australian summer monsoon was weaker, less variable from year to year (possibly indicative of reduced ENSO variability), and characterized by more within-season flood pulses than present. In contrast to today, the delivery of moisture appears to have been dominated by eastward propagating convective coupled waves associated with the Madden-Julian Oscillation

    Oxidation Kinetics of Nicrofer-6025HT for Use in Elevated Temperature Electrochemical Devices

    Get PDF
    Recent advances in high temperature electrochemical devices have prompted research into potential materials for component fabrication

    The willingness to pay for mortality risk reductions: A comparison of the United States and Canada

    Full text link
    We present the results of two contingent valuation surveys conducted in Hamilton, Canada and nation-wide in the US to elicit WTP for reductions in one's risk of death. We find that the Values of a Statistical Life implied by WTP are very similar across the two studies, and range from 930,000to930,000 to 4.8 million (2000 US dollars). WTP increases with the size of the risk reduction, but varies little with the age of the respondents: people older than 70 years of age hold WTP values that are about one-third lower than those of other respondents. This effect is significant in Canada but not in the US. Health status of the respondent has limited effect on WTP. In general, these results provide only little or no evidence that VSL used in environmental policy analyses should be adjusted for the age or health status of people whose lives are saved by environmental policies

    The Willingness to Pay for Mortality Risk Reductions: A Comparison of the United States and Canada

    Full text link
    We present results for two contingent valuation surveys conducted in Hamilton, Canada and the US to elicit WTP for mortality risk reductions. We find similar Value of Statistical Life estimates across the two studies, ranging from USD 930,000 to USD 4.8 million (2000 US dollars). WTP increases with risk reduction size, but varies little with respondent age: individuals aged over 70 years hold WTP values approximately one-third lower than other respondents. Respondent health status has limited effect on WTP. These results provide little or no evidence for adjusting VSL estimates used in policy analyses for the affected population's age or health status
    corecore