Suchergebnisse

Many factors can affect a person's health, such as quality of life, how long they live, and whether or not they suffer diseases. These factors are referred to as determinants of health. The quality of environmental media related to oil sands developments in northeastern Alberta represents a concern to people at the local, national, and international level. The key determinants of people's exposure to chemical pollutants are: time-activity (where we spend time and what we do), interaction with indoor environments, diet, and occupation. In most instances these determinants explain most or all of what influences exposure to chemicals in the environment. One way to investigate the relationship between the quality of environmental media and human health risk is to perform a human health risk assessment (HHRA). A human health risk assessment is an important component of most environmental impact assessments of new oil sands development projects. Human health risk assessment is also likely to be a key requirement for understanding potential human health impacts of the release of oil sands process affected waters to the environment. A human health risk assessment is the process of determining if a particular chemical or other hazard in the environment (e.g., particulate matter) poses a health risk to people for a specific set of conditions. People are called receptors in human health risk assessment. It is not possible to tell where in time and space people will actually be in relation to where chemical pollution exists, and therefore the extent to which they are actually exposed. Thus assumptions need to be made about their exposures to allow us to assess human health risk. Human health risk assessments are prepared by professional consultants (scientists and engineers) for government, industry and other organizations. This is done to help decision makers, especially policy makers and regulators, understand potential health impacts from the release of chemical pollutants into the environment by industrial operations. This type of information – along with social, economic, and other information – can help to inform policy and regulatory decisions that help protect people from chemical exposures as a result of pollution. Human health risk assessment procedures described here are normally accepted by regulatory agencies because they are, purposely, conservative. This conservatism makes it less likely to under estimate potential exposures and human risk and more likely that resulting regulatory decisions made will protect people from chemical pollution by industrial operations in real situations.

Many factors can affect a person's health, such as quality of life, how long they live, and whether or not they suffer diseases. These factors are referred to as determinants of health. The quality of environmental media related to oil sands developments in northeastern Alberta represents a concern to people at the local, national, and international level. The key determinants of people's exposure to chemical pollutants are: time-activity (where we spend time and what we do), interaction with indoor environments, diet, and occupation. In most instances these determinants explain most or all of what influences exposure to chemicals in the environment. One way to investigate the relationship between the quality of environmental media and human health risk is to perform a human health risk assessment (HHRA). A human health risk assessment is an important component of most environmental impact assessments of new oil sands development projects. Human health risk assessment is also likely to be a key requirement for understanding potential human health impacts of the release of oil sands process affected waters to the environment. A human health risk assessment is the process of determining if a particular chemical or other hazard in the environment (e.g., particulate matter) poses a health risk to people for a specific set of conditions. People are called receptors in human health risk assessment. It is not possible to tell where in time and space people will actually be in relation to where chemical pollution exists, and therefore the extent to which they are actually exposed. Thus assumptions need to be made about their exposures to allow us to assess human health risk. Human health risk assessments are prepared by professional consultants (scientists and engineers) for government, industry and other organizations. This is done to help decision makers, especially policy makers and regulators, understand potential health impacts from the release of chemical pollutants into the environment by industrial operations. This type of information – along with social, economic, and other information – can help to inform policy and regulatory decisions that help protect people from chemical exposures as a result of pollution. Human health risk assessment procedures described here are normally accepted by regulatory agencies because they are, purposely, conservative. This conservatism makes it less likely to under estimate potential exposures and human risk and more likely that resulting regulatory decisions made will protect people from chemical pollution by industrial operations in real situations.

We demonstrate an alkali modification process to produce highly dispersed ultrafine Pt nanoclusters with metallic Pt$^0$ and oxidized Pt$^{2+}$ species as co-catalyst anchored on nanosheet-constructed yolk-shell TiO$_2$ (NYTiO$_2$-Pt) acting as light harvesting reactor for highly efficient photocatalytic H$_2$ production. Benefiting from the high surface area, highly dispersed ultrafine Pt nanoclusters (~0.6 nm) with Pt$^0$ and Pt$^{2+}$ species and special nanosheet-constructed yolk-shell structure, this novel light harvesting reactor exhibits excellent performance for photocatalytic H$_2$ production. The NYTiO$_2$-Pt-0.5 (0.188 wt% Pt) demonstrates an unprecedentedly high H$_2$ evolution rate of 20.88 mmol h$^{−1}$ g$^{−1}$ with excellent photocatalytic stability, which is 87 times than that of NYTiO$_2$-Pt-3.0 (0.24 mmol h$^{−1}$ g$^{−1}$, 1.88 wt% Pt), and also much higher than those of other TiO$_2$ nanostructures with the same Pt content. Such H$_2$ evolution rate is the highest reported for photocatalytic H$_2$ production with such a low Pt content under simulated solar light. Our strategy here suggests that via alkali modifying the photocatalysts, we can not only enhance the H$_2$ production for solar energy conversion but also significantly decrease the noble metal content for cost saving. ; B. L. Su acknowledges the Chinese Central Government for an "Expert of the State" position in the Program of the "Thousand Talents" and a Life Membership at the Clare Hall, Cambridge and the financial support of the Department of Chemistry, University of Cambridge. Y. Li acknowledges Hubei Provincial Department of Education for the "Chutian Scholar" program. T. H. acknowledges support from the Royal Academy of Engineering through a Research Fellowship and an EPSRC Impact acceleration grant. This work is supported by the National Key Research and Development Program of China (2016YFA0202602), Program for Changjiang Scholars and Innovative Research Team in University (IRT_15R52), International Science & Technology Cooperation Program of China (2015DFE52870), National Natural Science Foundation of China (51302204 and 51502225) and the Fundamental Research Funds for the Central Universities (WUT: 2016 029).

The European Union is working toward providing 2-MW, coaxial-cavity, continuous-wave (cw) 170-GHz gyrotrons for ITER. Their design is based on results,from an experimental preprototype tube having a pulse length of several milliseconds, in operation at Forschungszentrum Karlsruhe (FZK) for several years now. The first industrial prototype tube was designed for cw operation but, in a first phase, aimed at a pulse length of 1 s at the European Gyrotron Test Facility in Lausanne, Switzerland, as part of a phased testing/development program. (1 s, 60 s, cw). The first experimental results of the operation of this prototype gyrotron are reported here. The microwave generation was characterized at very short pulse length (<0.01 s) using a load on loan from FZK, and the highest measured output power was 1.4 MW, at a beam energy significantly lower than the design value (83 k V instead of 90 kV), limited by arcing in the tube. The radio frequency (rf) beat, profile wets measured to allow reconstruction of the phase and amplitude profile at the window and to provide the necessary information permitting proper alignment of the compact rf loads prior to pulse extension. Arcs in the tube limited the pulse length extension to a few tens of milliseconds. According to present planning, the tube is going to be opened, inspected, and refurbished, depending on the results of the inspection, to allow testing of an improved version of the mode launcher and replacement of some subassemblies.

30 pags., 13 figs., 4 tabs. ; We present the inter-comparison of delta slant column densities (SCDs) and vertical profiles of nitrous acid (HONO) derived from measurements of different multiaxis differential optical absorption spectroscopy (MAXDOAS) instruments and using different inversion algorithms during the Second Cabauw Inter-comparison campaign for Nitrogen Dioxide measuring Instruments (CINDI- 2) in September 2016 at Cabauw, the Netherlands (51.97° N, 4.93° E). The HONO vertical profiles, vertical column densities (VCDs), and near-surface volume mixing ratios are compared between different MAX-DOAS instruments and profile inversion algorithms for the first time. Systematic and random discrepancies of the HONO results are derived from the comparisons of all data sets against their median values. Systematic discrepancies of HONO delta SCDs are observed in the range of ±0:3×1015 molec. cm2, which is half of the typical random discrepancy of 0:6× 1015 molec. cm2. For a typical high HONO delta SCD of 2×1015 molec. cm2, the relative systematic and random discrepancies are about 15% and 30 %, respectively. The inter-comparison of HONO profiles shows that both systematic and random discrepancies of HONO VCDs and nearsurface volume mixing ratios (VMRs) are mostly in the range of ∼ ±0:5×1014 molec. cm2 and ∼ ±0:1 ppb (typically ∼ 20 %). Further we find that the discrepancies of the retrieved HONO profiles are dominated by discrepancies of the HONO delta SCDs. The profile retrievals only contribute to the discrepancies of the HONO profiles by ∼ 5 %. However, some data sets with substantially larger discrepancies than the typical values indicate that inappropriate implementations of profile inversion algorithms and configurations of radiative transfer models in the profile retrievals can also be an important uncertainty source. In addition, estimations of measurement uncertainties of HONO dSCDs, which can significantly impact profile retrievals using the optimal estimation method, need to consider not only DOAS fit errors, but also atmospheric variability, especially for an instrument with a DOAS fit error lower than ∼ 3×1014 molec. cm2. The MAX-DOAS results during the CINDI-2 campaign indicate that the peak HONO levels (e.g. near-surface VMRs of ∼ 0:4 ppb) often appeared in the early morning and below 0.2 km. The near-surface VMRs retrieved from the MAXDOAS observations are compared with those measured using a co-located long-path DOAS instrument. The systematic differences are smaller than 0.15 and 0.07 ppb during early morning and around noon, respectively. Since true HONO values at high altitudes are not known in the absence of real measurements, in order to evaluate the abilities of profile inversion algorithms to respond to different HONO profile shapes, we performed sensitivity studies using synthetic HONO delta SCDs simulated by a radiative transfer model with assumed HONO profiles. The tests indicate that the profile inversion algorithms based on the optimal estimation method with proper configurations can reproduce the different HONO profile shapes well. Therefore we conclude that the features of HONO accumulated near the surface derived from MAX-DOAS measurements. ; Funding for this study was provided by ESA through the CINDI-2 (ESA contract no. 4000118533/16/I-Sbo) and FRM4DOAS (ESA contract no. 4000118181/16/I-EF) projects, by the NSFC (grant no. 41805027), the Russian Foundation for Basic Research (grant no. 18-35-00682), the Russian Academy of Sciences (grant nos. 0150-2018-0052 and 0129-2019- 0002), NASA's Atmospheric Composition Program (grant no. NASA-16-NUP2016-0001), the US National Science Foundation (AGS-1620530 award), and the European Union's Horizon 2020 research and innovation programme through the ACTRIS-2 transnational access programme (grant no. 654109). The AIOFM group is grateful for the support by the NSFC (grant no. 41530644). The article processing charges for this open-access publication were covered by the Max Planck Society

Reducing global emissions will require a global cosmopolitan culture built from detailed attention to conflicting national climate change frames (interpretations) in media discourse. The authors analyze the global field of media climate change discourse using 17 diverse cases and 131 frames. They find four main conflicting dimensions of difference: validity of climate science, scale of ecological risk, scale of climate politics, and support for mitigation policy. These dimensions yield four clusters of cases producing a fractured global field. Positive values on the dimensions show modest association with emissions reductions. Data-mining media research is needed to determine trends in this global field

This is the final version of the article. Available from SAGE Publications via the DOI in this record. ; Reducing global emissions will require a global cosmopolitan culture built from detailed attention to conflicting national climate change frames (interpretations) in media discourse. The authors analyze the global field of media climate change discourse using 17 diverse cases and 131 frames. They find four main conflicting dimensions of difference: validity of climate science, scale of ecological risk, scale of climate politics, and support for mitigation policy. These dimensions yield four clusters of cases producing a fractured global field. Positive values on the dimensions show modest association with emissions reductions. Data-mining media research is needed to determine trends in this global field.