Metal shearing energy absorber

A metal shearing energy absorber is described. The absorber is composed of a flat thin strip of metal which is pulled through a slot in a cutter member of a metal, harder than the metal of the strip. The slot's length, in the direction perpendicular to the pull direction, is less than the strip's width so that as the strip is pulled through the slot, its edges are sheared off, thereby absorbing some of the pulling energy. In one embodiment the cutter member is a flat plate of steel, while in another embodiment the cutter member is U-shaped with the slot at its base

Do Political Parties Matter? - Evidence from German Communities

The paper aims to test whether partisanship affects policy outcomes at the local level. While the literature has presented comprehensive evidence for partisan effects on policy outcomes at the state and federal level, recent findings suggest that partisan effects may be absent at the city and municipality level. Using detailed data on public goods and service spending, we assess the link between the partisanship of local councils and the composition of public good spending of German localities. Firstly, we estimate panel data models assessing whether changes in partisanship impact per-capita-spending in different spending-categories. Secondly, we investigate whether left-wing or right-wing communities differ in their spending response to exogenous revenue shocks during their legislative term (among others induced by changes of the personal income tax base assigned to communities). Using propensity score matching and weighting, the approach compares responses in comparable municipalities, which differ in the partisan composition of their local council. Based on both strategies, we find moderate partisan effects only

Inelastic scattering in ocean water and its impact on trace gas retrievals from satellite data

Over clear ocean waters, photons scattered within the water body contribute significantly to the upwelling flux. In addition to elastic scattering, inelastic Vibrational Raman Scattering (VRS) by liquid water is also playing a role and can have a strong impact on the spectral distribution of the outgoing radiance. Under clear-sky conditions, VRS has an influence on trace gas retrievals from space-borne measurements of the backscattered radiance such as from e.g. GOME (Global Ozone Monitoring Experiment). The effect is particularly important for geo-locations with small solar zenith angles and over waters with low chlorophyll concentration.<br> <br> In this study, a simple ocean reflectance model (Sathyendranath and Platt, 1998) accounting for VRS has been incorporated into a radiative transfer model. The model has been validated by comparison with measurements from a swimming-pool experiment dedicated to detect the effect of scattering within water on the outgoing radiation and also with selected data sets from GOME. The comparisons show good agreement between experimental and model data and highlight the important role of VRS.<br> <br> To evaluate the impact of VRS on trace gas retrieval, a sensitivity study was performed on synthetic data. If VRS is neglected in the data analysis, errors of more than 30% are introduced for the slant column (<i>SC</i>) of BrO over clear ocean scenarios. Exemplarily DOAS retrievals of BrO from real GOME measurements including and excluding a VRS compensation led to comparable results as in the sensitivity study, but with somewhat smaller differences between the two analyses.<br> <br> The results of this work suggest, that DOAS retrievals of atmospheric trace species from measurements of nadir viewing space-borne instruments have to take VRS scattering into account over waters with low chlorophyll concentrations, and that a simple correction term is enough to reduce the errors to an acceptable level

Exclusion of Stellar Companions to Exoplanet Host Stars

Given the frequency of stellar multiplicity in the solar neighborhood, it is important to study the impacts this can have on exoplanet properties and orbital dynamics. There have been numerous imaging survey projects established to detect possible low-mass stellar companions to exoplanet host stars. Here we provide the results from a systematic speckle imaging survey of known exoplanet host stars. In total, 71 stars were observed at 692~nm and 880~nm bands using the Differential Speckle Survey Instrument (DSSI) at the Gemini-North Observatory. Our results show that all but 2 of the stars included in this sample have no evidence of stellar companions with luminosities down to the detection and projected separation limits of our instrumentation. The mass-luminosity relationship is used to estimate the maximum mass a stellar companion can have without being detected. These results are used to discuss the potential for further radial velocity follow-up and interpretation of companion signals.Comment: 11 pages, 4 figures, 3 tables, accepted for publication in A

Temporal and spatial variability of glyoxal as observed from space

Glyoxal, CHO.CHO, is produced during the oxidation of volatile organic compounds, VOC, released by anthropogenic activities, biogenic processes and biomass burning. It has a short chemical lifetime of a few hours in the boundary layer and lower troposphere and therefore serves as an indicator and a marker of photochemical hot-spots and their response to changing atmospheric conditions around the globe. For this reason more than five years of CHO.CHO observations (2002–2007), retrieved from the radiances measured by the satellite instrument SCIAMACHY, were obtained and analyzed both temporally and spatially. The largest columns of CHO.CHO (&amp;gt;6.10&lt;sup&gt;14&lt;/sup&gt; molec cm&lt;sup&gt;&amp;minus;2&lt;/sup&gt;) are found in the tropical and sub-tropical regions, associated with high biological activity and the plumes from vegetation fires. The majority of the identified hot spots are characterized by a well-defined seasonality: the highest values being observed during the warm and dry periods as a result of the enhanced biogenic, primarily isoprene, emissions and/or biomass burning from natural or man-made fires. The regions influenced by anthropogenic pollution also encounter enhanced amounts of glyoxal. The ratio &quot;CHO.CHO to HCHO, R&lt;sub&gt;&lt;I&gt;GF&lt;/I&gt;&lt;/sub&gt;&quot; over the biogenically influenced photochemical hot-spots is approximately 0.045. For the studied regions, the presence of pyrogenic and anthropogenic emissions increases and decreases this number respectively. Although the 2002–2007 period of observation is limited, over the northeastern Asia a significant annual increase in CHO.CHO in addition to a seasonal cycle is reported

Tropospheric O₃ over Indonesia during biomass burning events measured with GOME (Global Ozone Monitoring Experiment) and compared with trajectory analysis

International audienceTropospheric ozone columns of up to 50 DU were observed by GOME (Global Ozone Monitoring Experiment) above Indonesia in September 1997, while only background amounts were measured in September 1998. The Traj.x trajectory model along with BRemen's Atmospheric PHOtochemical model (BRAPHO) were used to investigate the higher than average ozone columns above Indonesia. The transport analysis reveals that biomass burning over central Africa and northern Australia does not significantly influence ozone columns over Indonesia in September 1997. El Niño conditions, leading to extreme dryness and uncontrolled fires in Indonesia, produced ozone precursors, which are initially only slowly advected westwards to the central Indian Ocean. Joint transport and chemistry modelling was able to reproduce the spatial distribution and amounts of ozone, NO2 and formaldehyde columns over Indonesia. The chemistry modelling shows a net production of 3.1 Tg of ozone produced by biomass burning in Indonesia in September 1997. Transport analysis further reveals that ozone columns over the Indian Ocean, between 10 and 20° S can be accounted for by the mixing of air masses containing NOx from lightning over the Congo Basin with air masses containing volatile organic compounds from biomass burning

SCIAMACHY formaldehyde observations: constraint for isoprene emission estimates over Europe?

Formaldehyde (HCHO) is an important intermediate compound in the degradation of volatile organic compounds (VOCs) in the troposphere. Sources of HCHO are largely dominated by its secondary production from VOC oxidation, methane and isoprene being the main precursors in unpolluted areas. As a result of the moderate lifetime of HCHO, its spatial distribution is determined by reactive hydrocarbon emissions. We focus here on Europe and investigate the influence of the different emissions on HCHO tropospheric columns with the CHIMERE chemical transport model in order to interpret the comparisons between SCIAMACHY and simulated HCHO columns. Europe was never specifically studied before for these purposes using satellite observations. The bias between measurements and model is less than 20% on average. The differences are discussed according to the errors on the model and the observations and remaining discrepancies are attributed to a misrepresentation of biogenic emissions. This study requires the characterisation of: (1) the model errors and performances concerning formaldehyde. The errors on the HCHO columns, mainly related to chemistry and mixed emission types, are evaluated to 2&amp;times;10&lt;sup&gt;15&lt;/sup&gt; molecule/cm&lt;sup&gt;2&lt;/sup&gt; and the model performances evaluated using surface measurements are satisfactory (~13%); (2) the observation errors that define the needs in spatial and temporal averaging for meaningful comparisons. Using SCIAMACHY observations as constraint for biogenic isoprene emissions in an inverse modelling scheme reduces their uncertainties by about a factor of two in region of intense emissions. The retrieved correction factors for the isoprene emissions range from a factor of 0.15 (North Africa) to a factor of 2 (Poland, the United Kingdom) depending on the regions