Effect of local and regional sources on the isotopic composition of nitrous oxide in the tropical free troposphere and tropopause layer

Measurements and models of the spatiotemporal variability of surface N 2O mixing ratios and isotopic compositions are increasingly used to constrain the global N2O budget. However, large variability observed on the small spatial scales of soil chambers and shipboard sampling, which appears to be very sensitive to local environmental conditions, has made extrapolation to the global scale difficult. In this study, we present measurements of the isotopic composition of N2O (δ 15Nbulk, δ15N, δ15N, and δ18O) from whole-air samples collected at altitudes of 0.5 to 19km by the NASA DC-8 and WB-57 aircraft during the Costa Rica-Aura Validation Experiment (CR-AVE) and the Tropical Composition, Cloud and Climate Coupling Experiment (TC4) campaigns in January-February 2006 and July-August 2007, respectively. The vertical profiles of isotopic composition showed predictable, repeating patterns consistent with the influence of a surface source at lower altitudes and the influence of stratospheric photochemistry in the lower stratosphere. Their correlations with marine tracers at lower altitudes are consistent with a predominantly oceanic source, although a soil source cannot be ruled out. Measurements in a combustion plume revealed a strong depletion in 15N at the central nitrogen atom (i.e., low δ15N values), providing new information on N2O isotopic compositions from combustion. This new data set demonstrates that a coherent picture of the isotopic composition of tropospheric N2O is possible at currently attainable precisions and that its variations from 0.5 km to the lower stratosphere are a useful tool in investigating the sources and distributions of this important greenhouse gas. Copyright 2010 by the American Geophysical Union

2-Axis Electric Off-Road Bucket Seat Bases

Off-road vehicle bucket seats are currently restricted to a single position relative to the floor of the vehicle. Drivers and riders desire the ability to adjust their seat position to increase comfort and allow for a greater size range of riders to fit safely within the cabin or roll cage. To develop a viable solution, the team has gone through an extensive design process and has constructed a functioning prototype. This Final Design Report encapsulates the entire design process and concludes with recommendations for changes we would make looking both back in review as well as moving forward with further iterations of the product

Documentation of the data analysis system for the gamma ray monitor aboard OSO-H

The programming system is presented which was developed to prepare the data from the gamma ray monitor on OSO-7 for scientific analysis. The detector, data, and objectives are described in detail. Programs presented include; FEEDER, PASS-1, CAL1, CAL2, PASS-3, Van Allen Belt Predict Program, Computation Center Plot Routine, and Response Function Programs

Use of Global Electrochemical Techniques to Characterize Localized Corrosion Behavior on Aluminum Alloys

Precipitated intermetallic phases strengthen aluminum aircraft alloys; these inclusions also establish localized electrochemical environments, significantly influencing the bulk corrosion behavior of such alloys. To gain insight on the effects of intermetallic phases on the bulk corrosion behavior, two established forms of electrochemical characterization techniques were used, polarization scans and impedance spectroscopy. This effort was undertaken to: Provide a statistical body of electrochemical data for aluminum alloys, Provide fundamental electrochemical parameters to aide in a continuum scale modeling effort, Validate the effect of solution chemistry on bulk corrosion behavior, Determine the influence of precipitated intermetallic phases on the bulk corrosion behavior, Decouple the metal-coating interface behavior from bulk corrosion behavior in continuing tests on coated aluminum

Characteristics of successful commercialisation from university-industry research collaboration in Ontario, Canada

Canadian firms invest considerably less in research and development as a proportion of GDP than in many other OECD countries. As a result of low private sector research intensity, universities represent a comparatively large proportion of Canadian research. In order to improve university technology transfer and the absorptive capacity of its industries, Canada offers among the highest rates of government support for universityindustry research collaboration (UIRC) in the world. The government granting agencies that administer these subsidies seek to identify and fund the UIRC projects that have the greatest likelihood of commercialisation. There is considerable debate among practitioners about what UIRC characteristics are associated with commercial outcomes. Although the mechanisms of effective research collaboration and university technology transfer have been well studied, the academic literature on this specific problem is surprisingly sparse considering its growing importance to policy makers. This study examined the relationship between the characteristics of various stakeholders in UIRCs, namely academic researchers, universities, firms and governments, and commercial outcomes from UIRC. Specifically, three hypotheses were developed and tested based on the unique context of Canada’s national innovation system and the extant literature. First, Hypothesis 1 built upon the concept explored in previous studies of how economic behaviour is “embedded” in social networks to posit that researchers who are less embedded within academia will have a higher likelihood of commercial outcomes from UIRCs. Next, motivated by the growing body of literature that has found government subsidies help to stimulate greater private sector research expenditures, Hypothesis 2 suggests that UIRCs with higher cash and in-kind contributions by firms will have a higher likelihood of commercial outcomes. Finally, Hypothesis 3 proposes that UIRCs in industry sectors with higher research intensity will have a higher likelihood of commercial outcomes, since prior studies have demonstrated that research intensity improves firm absorptive capacity. A novel dataset was developed from the historical records of the Ontario Centres of Excellence, a government granting agency in the province of Ontario, and from other public sources. The UIRC project was the unit of observation and the size of the sample was 682 observations. The dependent variables represented whether or not the UIRC project achieved a commercial outcome. Five independent variables were used to test the hypotheses using binomial and multinomial Logit regression, and 19 additional control variables were included in the model. Hypothesis 1 was tested using a novel categorisation of researchers based on their level of embeddedness in academia, and found that it was significantly associated with commercial outcomes. However, the results suggested that the directionality of the relationship was opposite to what was hypothesised. Additional testing confirmed that, contrary to what was hypothesised, more embedded researchers have a higher likelihood of commercial outcomes. Therefore, the findings may shed further light on mixed results from previous studies by exploring the commercialisation behaviour of certain categories of embedded researchers. Hypothesis 2 was tested using separate measures of firm cash and in-kind contributions to UIRCs. The results found that in-kind contributions are significantly associated with commercialisation, but that cash contributions are not. In fact, in-kind contributions are positively associated with licensing outcomes in particular. This study is among the first to link firm contributions to UIRCs with their commercial outcomes at a project level. Preliminary testing indicated support for Hypothesis 3 by finding a significant and positive association between industry sector and commercialisation. Additional testing found further evidence that UIRCs in industry sectors with higher research intensity had a higher likelihood of commercialisation. The findings suggest important industry differences in UIRC commercialisation patterns. However, the absence of data on UIRCs in life sciences, which represent approximately 50 of all university technology transfer activity, is an important limitation on their generalisability. The study makes four recommendations to policy makers and government granting agencies based on its findings: 1. Develop awareness and education programs that encourage older, more career advanced and high-quality researchers to become involved in UIRC and commercialisation. 2. Design UIRC support programs and selection criteria to encourage in-kind contributions by firms. 3. Concentrate efforts on developing world class research capabilities and commercialisation infrastructure at a small number of large universities. 4. Focus on supporting research collaboration between universities and the most research intensive industries to maximise the likelihood of commercialisation

North America’s oldest boreal trees are more efficient water users due to increased [CO2], but do not grow faster

Due to anthropogenic emissions and changes in land use, trees are now exposed to atmospheric levels of [CO2] that are unprecedented for 650,000 y [Lüthi et al. (2008) Nature 453:379–382] (thousands of tree generations). Trees are expected to acclimate by modulating leaf–gas exchanges and alter water use efficiency which may result in forest productivity changes. Here, we present evidence of one of the strongest, nonlinear, and unequivocal postindustrial increases in intrinsic water use efficiency (iWUE) ever documented (+59%). A dual-isotope tree-ring analysis (δ13C and δ18O) covering 715 y of growth of North America’s oldest boreal trees (Thuja occidentalis L.) revealed an unprecedented increase in iWUE that was directly linked to elevated assimilation rates of CO2 (A). However, limited nutrient availability, changes in carbon allocation strategies, and changes in stomatal density may have offset stem growth benefits awarded by the increased iWUE. Our results demonstrate that even in scenarios where a positive CO2 fertilization effect is observed, other mechanisms may prevent trees from assimilating and storing supplementary anthropogenic emissions as above-ground biomass. In such cases, the sink capacity of forests in response to changing atmospheric conditions might be overestimated

Tracking the reflexivity of the (dis)engaged citizen: some methodological reflections

The relationship between governments and citizens in many contemporary democracies is haunted by uncertainty and sociologists face the task of listening effectively to citizens’ own reflections on this uncertain relationship. This article reflects on the qualitative methodology of a recently completed UK project which used a combination of diary and multiple interviews/ focus groups to track over a fieldwork period of up to a year citizens’ reflections on their relationship to a public world and the contribution to this of their media consumption. In particular, the article considers how the project’s multiple methods enabled multiple angles on the inevitable artificiality and performative dimension of the diary process, resulting in rich data on people’s complex reflections on the uncertain position of the contemporary citizen

Stem emissions of monoterpenes, acetaldehyde, and methanol from Scots pine (Pinus sylvestris L.) affected by tree water relations and cambial growth

Abstract Tree stems are an overlooked source of volatile organic compounds (VOCs). Their contribution to ecosystem processes and total VOC fluxes is not well studied, and assessing it requires better understanding of stem emission dynamics and their driving processes. To gain more mechanistic insight into stem emission patterns, we measured monoterpene, methanol, and acetaldehyde emissions from the stems of mature Scots pines (Pinus sylvestris L.) in a boreal forest over three summers. We analysed the effects of temperature, soil water content, tree water status, transpiration, and growth on the VOC emissions, and used generalized linear models to test their relative importance in explaining the emissions. We show that Scots pine stems are considerable sources of monoterpenes, methanol, and acetaldehyde, and their emissions are strongly regulated by temperature. However, even small changes in water availability affected the emission potentials: increased soil water content increased the monoterpene emissions within a day, whereas acetaldehyde and methanol emissions responded within two to four days. This lag corresponded to their transport time in the xylem sap from the roots to the stem. Moreover, the emissions of monoterpenes, methanol, and acetaldehyde were influenced by the cambial growth rate of the stem with six- to ten-day lags. This article is protected by copyright. All rights reserved.Peer reviewe

Effect of strain rate on tensile mechanical properties of high-purity niobium single crystals for SRF applications

An investigation of the mechanical properties of high-purity niobium single crystals is presented. Specimens were cut with different crystallographic orientations from a large grain niobium disk and uniaxial tensile tests were conducted at strain rates between 10-4 and 103 s-1. The logarithmic strain rate sensitivity for crystals oriented close to the center of a tensile axis inverse pole figure (IPF) is ~0.14 for all strain rates. The strain at failure (ranging from 0.4 to 0.9) is very sensitive to crystal orientation and maximal at ~10-2 s-1 for crystals oriented close to the center of an IPF. The high anisotropy observed at quasi-static strain rates decreased with increasing strain rate. The activation of multiple slip systems in the dynamic tests could account for this reduction in anisotropy. A transition from strain hardening to softening in the plastic domain was observed at strain rates greater than approximately 6 × 10-2 s-1 for crystals oriented close to the center of a tensile axis IPF. Shear bands were observed in specimens with orientations having similarly high Schmid factors on both {110} and {112} slip families, and they are correlated with reduced ductility. Crystal rotations at fracture are compared for the different orientations using scanning electron microscopy images and EBSD orientation maps. A rotation toward the terminal stable [101] orientation was measured for the majority of specimens (with tensile axes more than ~17° from the [001] direction) at strain rates between 1.28 × 10-2 and 1000 s-1.The authors would like to acknowledge the work of CERN's Materials, Metrology and Non-Destructive Testing (EN-MME-MM) section for granting access to their equipment for specimen preparation and scanning electron microscope (SEM) analyses. The authors would also like to thank Mr. Larry Vladic of Elite Motion LLC for lending us the high-speed camera during the high strain rate tests performed ASU. This Marie Sklodowska-Curie Action (MSCA) Innovative Training Network (ITN) receives funding from the European Union's H2020 Framework Programme under grant agreement no. 764879. T.R. Bieler, D. Kang, E. Pai Kulyadi, P. Eisenlohr, C. Kale, and K.N. Solanki acknowledge support from DOE/OHEP grant DE-SC0009962

Intercomparison of an Aerosol Chemical Speciation Monitor (ACSM) with ambient fine aerosol measurements in downtown Atlanta, Georgia

Currently, there are a limited number of field studies that evaluate the long-term performance of the Aerodyne Aerosol Chemical Speciation Monitor (ACSM) against established monitoring networks. In this study, we present seasonal intercomparisons of the ACSM with collocated fine aerosol (PM_2.5) measurements at the Southeastern Aerosol Research and Characterization (SEARCH) Jefferson Street (JST) site near downtown Atlanta, GA, during 2011–2012. Intercomparison of two collocated ACSMs resulted in strong correlations (<i>r</i>² > 0.8) for all chemical species, except chloride (<i>r</i>² = 0.21) indicating that ACSM instruments are capable of stable and reproducible operation. In general, speciated ACSM mass concentrations correlate well (<i>r</i>² > 0.7) with the filter-adjusted continuous measurements from JST, although the correlation for nitrate is weaker (<i>r</i>² = 0.55) in summer. Correlations of the ACSM NR-PM₁ (non-refractory particulate matter with aerodynamic diameter less than or equal to 1 μm) plus elemental carbon (EC) with tapered element oscillating microbalance (TEOM) PM_2.5 and Federal Reference Method (FRM) PM₁ mass are strong with <i>r</i>² > 0.7 and <i>r</i>² > 0.8, respectively. Discrepancies might be attributed to evaporative losses of semi-volatile species from the filter measurements used to adjust the collocated continuous measurements. This suggests that adjusting the ambient aerosol continuous measurements with results from filter analysis introduced additional bias to the measurements. We also recommend to calibrate the ambient aerosol monitoring instruments using aerosol standards rather than gas-phase standards. The fitting approach for ACSM relative ionization for sulfate was shown to improve the comparisons between ACSM and collocated measurements in the absence of calibrated values, suggesting the importance of adding sulfate calibration into the ACSM calibration routine