Carbon and Nitrogen Isotopic Ratio of the Water-Insoluble Fraction in Air Filter Particulate Matter

Particulate matter samples were collected during two episodes of thermal inversion (14.01-2.3.2006) and at four different air monitoring stations in Krakow (Agro: urban background site, Indu: industrial site at Nowa Huta, Poly: domestic coal heating district, Traffic: traffic site) and from the Zakopane sub-urban mountain site (Zakopane), dominated by domestic coal heating. The carbon and nitrogen isotopic compositions of aerosol particles collected in the city of Krakow were measured in 2006 as part of the JRC-IES Krakow project, for which the samples were taken. A total of 42 samples (including 24 source samples) was analysed by Isotope Ratio Mass Spectrometry (IRMS) for isotopic ratios of N and C. The results for samples from different locations show clear grouping of related samples. The leftover of samples provided within the Krakow project were stored in the refrigerator. After one year of cool storage the EA-IRMS measurement was repeated and water extraction was applied. The aim of this experiment was to get more isotopic data for source apportionment. The results showed that the isotopic values of some source samples obtained in 2007 are different from these measured in 2006. However, these differences were not observed for ambient air samples. The possible explanation could be improper storage condtions causing continued reactions between products adsorbed on the filter during storage in the refrigerator. The water extraction removed water soluble inorganic and organic nitrogen-containing compounds and caused the changes in delta15N vs. Air. In this study it is difficult to make a link between sources and ambient air samples after application of water extraction because of the problem with instability of isotopic compositions of the original sources samples.JRC.D.4-Isotope measurement

Determination by Isotope Ratio Mass Spectrometry of the Absolute Isotope Amount Fractions of Oxygen and Nitrogen in Nitrous Oxide

A measurement procedure for the complete isotope characterisation of atmospheric nitrous oxide sample has been developed and applied to establish a first Reference Material for this gas. The whole work has been based on the peculiar instrumental capabilites of "Avogadro" MAT 271IRMS. Additional hardware and software improvement has been done for this mass spectrometer to apply the proposed method.JRC.D.4-Isotope measurement

Report on the delta-VPBD-13C Measurements on Volatile Organic Compounds from Groundwater Samples using Compound Specific Isotope Analysis

The report shows that the Compound Specific Isotope Analysis (CSIA) methods for carbon were successfully applied to the analysis of Volatile Organic Chlorinate compounds (VO-Cl) from groundwater samples selected in an industrial site is seated in Borsbeek (Belgium). Former soil and groundwater investigations in this site indicated the presence of underground contamination by VO-Cl. This contamination was likely linked to the activities of two former dry cleaning facilities. This report describes the material, the techniques and the methods used for measuring the delta-VPBD-13C of the VO-Cl in the 25 groundwater samples from the industrial site of Borskbeek and that of 11 samples from experimental batches. This report also demonstrated the capability of IRMM's equipment and staff to respond external customers demands such as VITO and to provide accurate delta-VPBD-13C (%o) results with reliable uncertainties estimation calculated as budgets using GUIMworkbench networks. This work also provides evidence for the potential application of CSIA to two inter-dependent issues in field studies which are sources fingerprinting/apportionment and monitoring in situ VOC (Volatile Organic Compounds) degradation.JRC.D.4 - Isotope measurement

Intrinsic symmetry groups of links with 8 and fewer crossings

We present an elementary derivation of the "intrinsic" symmetry groups for knots and links of 8 or fewer crossings. The standard symmetry group for a link is the mapping class group \MCG(S^3,L) or \Sym(L) of the pair $(S^3,L)$. Elements in this symmetry group can (and often do) fix the link and act nontrivially only on its complement. We ignore such elements and focus on the "intrinsic" symmetry group of a link, defined to be the image $\Sigma(L)$ of the natural homomorphism \MCG(S^3,L) \rightarrow \MCG(S^3) \cross \MCG(L). This different symmetry group, first defined by Whitten in 1969, records directly whether $L$ is isotopic to a link $L'$ obtained from $L$ by permuting components or reversing orientations. For hyperbolic links both \Sym(L) and $\Sigma(L)$ can be obtained using the output of \texttt{SnapPea}, but this proof does not give any hints about how to actually construct isotopies realizing $\Sigma(L)$. We show that standard invariants are enough to rule out all the isotopies outside $\Sigma(L)$ for all links except $7^2_6$, $8^2_{13}$ and $8^3_5$ where an additional construction is needed to use the Jones polynomial to rule out "component exchange" symmetries. On the other hand, we present explicit isotopies starting with the positions in Cerf's table of oriented links which generate $\Sigma(L)$ for each link in our table. Our approach gives a constructive proof of the $\Sigma(L)$ groups.Comment: 72 pages, 66 figures. This version expands the original introduction into three sections; other minor changes made for improved readabilit

Source Apportionment of Nitrate Pollution in Surface Water Using Stable Isotopes of N and O in Nitrate and B: A Case Study in Flanders (Belgium)

Excess application to fields of animal manure or mineral fertilizers is generally assumed to be the major source of nitrate pollution in surface and groundwater in agricultural areas in Flanders (Belgium). The Flemish Environment Agency (VMM) suspects, but could not prove, that discharges of untreated domestic sewage or discharges containing mineral fertilizers from hydroculture in greenhouses are also contributing to the nitrate pollution observed in some of the agricultural areas. The objective of this study was to investigate, using stable isotope data of dissolved nitrate and boron, if these suspected sources significantly contribute to the nitrate pollution observed in selected surface water monitoring points in Flanders.JRC.D.4-Isotope measurement

String Loop Corrections to Kahler Potentials in Orientifolds

We determine one-loop string corrections to Kahler potentials in type IIB orientifold compactifications with either N=1 or N=2 supersymmetry, including D-brane moduli, by evaluating string scattering amplitudes.Comment: 80 pages, 4 figure

Aspects of (0,2) Orbifolds and Mirror Symmetry

We study orbifolds of (0,2) models and their relation to (0,2) mirror symmetry. In the Landau-Ginzburg phase of a (0,2) model the superpotential features a whole bunch of discrete symmetries, which by quotient action lead to a variety of consistent (0,2) vacua. We study a few examples in very much detail. Furthermore, we comment on the application of (0,2) mirror symmetry to the calculation of Yukawa couplings in the space-time superpotential.Comment: 13 pages, TeX (harvmac, big) with 4 enclosed PostScript figures, one reference adde

Duality in Heterotic Vacua With Four Supercharges

We study heterotic vacua with four supercharges in three and four space-time dimensions and their duals obtained as M/F-theory compactified on Calabi-Yau fourfolds. We focus on their respective moduli spaces and derive the Kahler potential for heterotic vacua obtained as circle compactifications of four-dimensional N=1 heterotic theories. The Kahler potential of the dual theory is computed by compactifying 11-dimensional supergravity on Calabi-Yau fourfolds. The duality between these theories is checked for K3-fibred fourfolds and an appropriate F-theory limit is discussed.Comment: 28 pages, LaTe