Biodiesel effects on particulate radiocarbon (14C) emissions from a diesel engine

Author Posting. © Elsevier B.V., 2008. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Journal of Aerosol Science 39 (2008): 667-678, doi:10.1016/j.jaerosci.2008.04.001.The relative amount of 14C in a sample of atmospheric particulate matter (PM), defined as percent modern carbon (pMC), allows EPA to infer the fraction of PM derived from anthropogenic pollution sources. With increased use of biofuels that contain 14C, the main assumption of the two-source model, that 14C is solely derived from biogenic sources, may become invalid. The goal of this study was to determine the 14C content of PM emitted from an off-highway diesel engine running on commercial grade biodiesel. Tests were conducted with an off-highway diesel engine running at 80% load fueled by various blends of soy-based biodiesel. A dilution tunnel was used to collect PM10 emissions on quartz filters that were analyzed for their 14C content using accelerator mass spectrometry. A mobility particle sizer and 5-gas analyzer provided supporting information on the particle size distribution and gas-phase emissions. The pMC of PM10 aerosol increased linearly with the percentage of biodiesel present in the fuel. Therefore, PM emissions resulting from increased combustion of biodiesel fuels will likely affect contemporary 14C apportionment efforts that attempt to split biogenic vs. anthropogenic emissions based on aerosol-14C content. Increasing the biodiesel fuel content also reduced emissions of total hydrocarbons (THC), PM10 mass, and particulate elemental carbon. Biodiesel had variable results on oxides of nitrogen (NOx) emissions

Scanning Tunneling Microscopy in TTF-TCNQ :direct proof of phase and amplitude modulated charge density waves

Charge density waves (CDW) have been studied at the surface of a cleaved TTF-TCNQ single crystal using a low temperature scanning tunneling microscope (STM) under ultra high vacuum (UHV) conditions. All CDW phase transitions of TTF-TCNQ have been identified. The measurement of the modulation wave vector along the a direction provides the first evidence for the existence of domains comprising single plane wave modulated structures in the temperature regime where the transverse wave vector of the CDW is temperature dependent, as hinted by the theory more than 20 years ago.Comment: To appear in Phys.Rev.Rapid. Com

‘There is a Time to be Born and a Time to Die’ (Ecclesiastes 3:2a): Jewish Perspectives on Euthanasia

Reviewing the publications of prominent American rabbis who have (extensively) published on Jewish biomedical ethics, this article highlights Orthodox, Conservative and Reform opinions on a most pressing contemporary bioethical issue: euthanasia. Reviewing their opinions against the background of the halachic character of Jewish (biomedical) ethics, this article shows how from one traditional Jewish textual source diverse, even contradictory, opinions emerge through different interpretations. In this way, in the Jewish debate on euthanasia the specific methodology of Jewish (bio)ethical reasoning comes forward as well as a diversity of opinion within Judaism and its branches

COLLISION INDUCED SCATTERINGSPECTRAL VIRIAL EXPANSION FOR COLLISION-INDUCED LIGHT SCATTERING IN GASES

On développe un formalisme général qui décrit la dépendance en fonction de la densité de la lumière dépolarisée diffusée par les fluctuations translationnelles dans les gaz. De plus, on a fait des mesures d'intensité absolue du spectre de diffusion de lumière dépolarisée de l'argon gazeux, dans le domaine de densité de 20 à 150 amagats et dans l'intervalle de fréquence de 7 à 150 cm-1. A toute fréquence, l'intensité I(ω) peut être développée en série de puissances de densité I(ω) = I2(ω) p2 + I3(ω) p3 + ... Le terme I2(ω) représente le spectre de la lumière diffusée, dû à l'anisotropie optique induite dans une paire d'atomes en collision, alors que I3(ω) représente la portion de l'anisotropie induite par une collision à trois centres qui ne peut être représentée comme une somme d'effets de collision à deux centres. Ceci est analogue au développement du viriel classique de pV. On présente les spectres pour les termes à deux et trois centres et on les compare avec les prévisions basées sur divers modèles pour l'anisotropie induite de polarisabilité.A general formalism is developed for the density dependence of depolarized light scattered by translational fluctuations in gases. In addition, absolute intensity measurements have been made of the depolarized light scattering spectrum of argon gas in the density range 20-150 amagats for the frequency range ω = 7-150 cm-1. At any given frequency, the intensity I(ω) can be expanded as a power series in the density I(ω) = I2(ω) p2 + I3(ω) p3 + ... The term I2(ω) is the light scattering spectrum caused by the optical anisotropy induced in a pair of atoms on collision, while I3(ω) represents the portion of the induced anisotropy in a three-body collision which cannot be represented as a sum of two-body effects. This is analogous to the familiar pV virial expansion. Spectra for the two- and three-body terms are reported and compared with predictions based on various models for the induced polarizability anisotropy

Beach State Recognition Using Argus Imagery and Convolutional Neural Networks

Nearshore morphology is a key driver in wave breaking and the resulting nearshore circulation, recreational safety, and nutrient dispersion. Morphology persists within the nearshore in specific shapes that can be classified into equilibrium states. Equilibrium states convey qualitative information about bathymetry and relevant physical processes. While nearshore bathymetry is a challenge to collect, much information about the underlying bathymetry can be gained from remote sensing of the surfzone. This study presents a new method to automatically classify beach state from Argus daytimexposure imagery using a machine learning technique called convolutional neural networks (CNNs). The CNN processed imagery from two locations: Narrabeen, New South Wales, Australia and Duck, North Carolina, USA. Three different CNN models are examined, one trained at Narrabeen, one at Duck, and one trained at both locations. Each model was tested at the location where it was trained in a self-test, and the single-beach models were tested at the location where it was not trained in a transfer-test. For the self-tests, skill (as measured by the F-score) was comparable to expert agreement (CNN F-values at Duck = 0.80 and Narrabeen = 0.59). For the transfer-tests, the CNN model skill was reduced by 24–48%, suggesting the algorithm requires additional local data to improve transferability performance. Transferability tests showed that comparable F-scores (within 10%) to the self-trained cases can be achieved at both locations when at least 25% of the training data is from each site. This suggests that if applied to additional locations, a CNN model trained at one location may be skillful at new sites with limited new imagery data needed. Finally, a CNN visualization technique (Guided-Grad-CAM) confirmed that the CNN determined classifications using image regions (e.g., incised rip channels, terraces) that were consistent with beach state labelling rules