Occurrence and fate of organic micropollutants (OMPs) in Lake Mälaren

The main objective of this study is to investigate the occurrence and fate of organic micropollutants (OMPs) in surface water in Lake Mälaren over one year, including their seasonal variations, correlations between compounds, spatial and vertical distribution. The water samples were enriched with solid phase extraction (SPE) and subsequently analyzed by ultra-high pressure liq-uid chromatography tandem mass spectrometry (UPLC-MS/MS). The applied multi-residue method, consisting of OMPs with a wide range of physico-chemical properties was earlier optimized and then assessed regarding its per-formance. From 122 tested target compounds, 74 obtained a good relative re-covery (60-145%) and 50 were detected at least once above limit of quantifica-tion (LOQ), which ranged from 0.010 and 10 ng/L. The highest detected con-centration was found for valproic acid (2600 ng/L) and lamotrigine (140 ng/L). The locations Ekoln and Västeråsfjärden were identified to be most affected by OMPs pollution. Seasonal patterns were observed for numerous OMPs and 7 compounds occurred without seasonal fluctuations. Only a few vertical distri-bution patterns and concentration gradients were observed, for instance, the deepest sampling depth (30m) from Ekoln showed considerable higher concen-trations than the upper sampling depths in February. A strong positive correla-tion was found for carbamazepine and lamotrigine, but also for other OMPs. Two industrial chemicals, tolyltriazole and tris(2-butoxylethyl)phosphate showed very good analytical performance parameters and were detected fre-quently and it is recommended to incorporate these compounds more regularly in future analysis. No correlations between water chemistry were observed. To the best of our knowledge, this study is the first one to report the occurrence and distribution of OMPs representing such wide physico-chemical properties, including industrial chemicals, in a Swedish lake

Differential equation models for surface reactions of SnO2 <<[SnO tief 2]>> nanowire gas sensors and their inverse modeling

Diese Diplomarbeit behandelt die mathematische Modellierung von Nanowire Gassensoren, also Sensoren in der Größenordnung einiger Nanometer die zur Detektion verschiedener Gase und deren Konzentration in der Umgebungsluft verwendet werden. Aktuell erforschte und enwickelte Gassensoren können schwer zwischen bestimmten Gasen unterscheiden, desswegen ermöglicht die mathematischen Modellierung ein tiefergehendes Verständnis der für den Sensorausschlag verantwortlichen Oberflächereaktionen auch eine Verbesserung dieser Kreuzselektivität. Die in dieser Arbeit hergeleiteten Sensormodelle setzen sich jeweils aus einem Oberflächenmodell, bestehend aus gewöhlichen Differentialgleichungen, und einem Ladungstransportmodell - beide paramterabhängig - zusammen und sagen die Änderung der Leitfähigkeit, verursacht durch eine Änderung der Temperature und der chemischen Zusammensetzung der Umgebungsluft, voraus. Wir präsentieren Oberflächenmodelle für alle wichtigen, für Anwendungen relevanten Gassorten, leiten sie her und diskutieren sie im Detail. Um eine spätere quantitative Analyse von Modellen und Messdaten zu ermöglichen, wurde die Theorie der Inversen Modellierung von dynamischen Modellen behandelt. Hierbei wurde besondere Aufmerksamkeit auf die asymptotische Theorie nichtlinearer Least Squares Schätzmethoden und auf dafür passende Optimierungsalgorithmen verwendet. Ein einparametriges Transportmodell in Kombination mit einem Oberflächenreaktionsmodell, bestehend aus 5 Parametern, wird benutzt um das Verhalten eines Geassensors, bestehend aus einem Netzwerk von Nanodrähten, in einer Edelgasatmosphäre zu simulieren. Hierzu wurden die Reaktionskonstanten und Parameter beider Modelle durch einen nichtlinearen Least Sqares Schätzprozesses gefittet, unter zuhilfenahme von Inverser Modellierung.This thesis deals with the modeling of metal oxide nanowire gas sensors, which are technical devices in the scale of nanometers, that are used to detect different gases in different concentrations in the atmosphere. As state of the art gas sensors show a low selectivity, the detailed modeling of the surface reactions caused by different test gases is essential to overcome this issue. The developed response models, described in this work, are composed of an ODE surface reaction model and a charge transport model (both parameter dependent) and predict the change of conductance of the sensor upon changes in the thermal and chemical environment. In this diploma thesis we present surface reaction models for the most important and test gas species that are relevant for applications, show their derivation and give a detailed discussion of their properties. In order to facilitate the simulation of the sensor response, the theory of inverse modeling of dynamic models, with special regard to the estimation of model parameters through nonlinear least squares estimators and suitable optimization algorithms, is discussed. A one parameter transport model in combination with a five parameter surface reaction model is used to simulate the response of a gas sensor consisting of a bundle of nanowires in an inert atmosphere. Reaction as well as conduction parameters is fitted in a nonlinear least squares estimation process, using inverse modeling techniques

Providing other people's trails for navigation assistance in physical environments

Asking other people the way has always been a widespread social wayfinding technique. In recent years wayfinding in unknown spatial environments has increasingly been supported by electronic navigation assistants. However, the social aspects of wayfinding, such as using other peoples’ experiences, have widely been ignored in the context of electronic navigation systems. In electronic environments such as the WWW the availability of community knowledge - also driven by Web 2.0 paradigms - becomes more and more valuable to users. Other people’s experiences, including recorded browsing paths and activities - so called user trails - are used for recommendation and navigation support and allow users to navigate vast information spaces more easily. In this paper we propose an approach for trail-based navigation in physical environments. An analysis and comparison of the concept of trails in both application areas establishes the basis for a trail model and the implementation of a trail-based navigation system prototype for mobile phones. Practical experiences with a prototype application and potential applications of trail-based navigation assistants are discussed in the context of a tourist scenario in the old town of Salzburg

Nahverkehr - intelligent und innovativ

NAHVERKEHR - INTELLIGENT UND INNOVATIV Politische Studien (Rights reserved) (-) Issue494.2020 Welche Bildung brauchen wir? (Rights reserved) ( - ) Issue492.2020 Jugend bewegt sich (Rights reserved) ( - ) Issue483.2019 Alt, krank, einsam? Zukunftsaufgabe Pflege (Rights reserved) ( - ) Issue478.2018 Nahverkehr - intelligent und innovativ (Rights reserved) ( - ) Issue473.2017 Migration : der Rechtsstaat hat es in der Hand (Rights reserved) ( - ) Issue460.2015 Integration durch Sport (Rights reserved) ( - ) Issue459.2015 Migration - eine europäische Herausforderung (Rights reserved) ( - ) Issue452.2013 Mobil in die Zukunft - Wege aus dem Stau (Rights reserved) ( - ) Issue446.2012 Agrarpolitik als Gesellschaftspolitik (Rights reserved) ( - ) Issue445.2012 Regionen richten sich für die Zukunft aus (Rights reserved) ( - ) Issue444.2012 Ressourcen - zu wertvoll, um sie zu verschwenden? (Rights reserved) ( - ) Issue442.2012 Frauen in Politik, Wirtschaft und Wissenschaft (Rights reserved) ( - ) Issue436.2011 Klimawandel als sicherheitspolitische Herausforderung (Rights reserved) ( -

Analysis of stress corrosion cracking in X80 pipeline steel: An approach from the Theory of Critical Distances

This paper presents an analysis of Stress Corrosion Cracking (SCC) based on the Theory of Critical Distances (TCD). The research is based on an experimental program composed of fracture specimens with notch radius varying from 0 mm (crack-like defect) up to 1 mm, and tensile specimens. A pipeline steel was used in this work (X80). It has been analysed in one hydrogen embrittlement situation. The study has been completed with Finite Elements Simulation analysis. The capacity of the TCD to analyse SCC processes has been proven.The authors of this paper would like to thank the Spanish Ministry of Economy and Competitivity for the support received for the research project MAT2014-58738-C3-3-R developed by the University of Cantabria

Chronic schistosomiasis suppresses HIV-specific responses to DNA-MVA and MVA-gp140 Env vaccine regimens despite antihelminthic treatment and increases helminth-associated pathology in a mouse model

Future HIV vaccines are expected to induce effective Th1 cell-mediated and Env-specific antibody responses that are necessary to offer protective immunity to HIV infection. However, HIV infections are highly prevalent in helminth endemic areas. Helminth infections induce polarised Th2 responses that may impair HIV vaccine-generated Th1 responses. In this study, we tested if Schistosoma mansoni (Sm) infection altered immune responses to SAAVI candidate HIV vaccines (DNA and MVA) and an HIV-1 gp140 Env protein vaccine (gp140) and whether parasite elimination by chemotherapy or the presence of Sm eggs (SmE) in the absence of active infection influenced the immunogenicity of these vaccines. In addition, we evaluated helminth-associated pathology in DNA and MVA vaccination groups. Mice were chronically infected with Sm and vaccinated with DNA+MVA in a prime+boost combination or MVA+gp140 in concurrent combination regimens. Some Sm-infected mice were treated with praziquantel (PZQ) prior to vaccinations. Other mice were inoculated with SmE before receiving vaccinations. Unvaccinated mice without Sm infection or SmE inoculation served as controls. HIV responses were evaluated in the blood and spleen while Sm-associated pathology was evaluated in the livers. Sm-infected mice had significantly lower magnitudes of HIV-specific cellular responses after vaccination with DNA+MVA or MVA+gp140 compared to uninfected control mice. Similarly, gp140 Env-specific antibody responses were significantly lower in vaccinated Sm-infected mice compared to controls. Treatment with PZQ partially restored cellular but not humoral immune responses in vaccinated Sm-infected mice. Gp140 Env-specific antibody responses were attenuated in mice that were inoculated with SmE compared to controls. Lastly, Sm-infected mice that were vaccinated with DNA+MVA displayed exacerbated liver pathology as indicated by larger granulomas and increased hepatosplenomegaly when compared with unvaccinated Sm-infected mice. This study shows that chronic schistosomiasis attenuates both HIV-specific T-cell and antibody responses and parasite elimination by chemotherapy may partially restore cellular but not antibody immunity, with additional data suggesting that the presence of SmE retained in the tissues after antihelminthic therapy contributes to lack of full immune restoration. Our data further suggest that helminthiasis may compromise HIV vaccine safety. Overall, these findings suggested a potential negative impact on future HIV vaccinations by helminthiasis in endemic areas.</p

The role of the testing rate on Small Punch tests for the estimation of fracture toughness in hydrogen embrittlement

ABSTRACT: In this paper, different techniques to test notched Small Punch (SPT) samples in fracture conditions in aggressive environments are studied, based on the comparison of the micromechanisms at different rates. Pre-embrittled samples subsequently tested in air at rates conventionally employed (0.01 and 0.002 mm/s) are compared to embrittled ones tested in environment at the same rates (0.01 and 0.002 mm/s) and at a very slow rate (5E-5 mm/s). A set of samples tested in environment under a set of constant loads that produce very slow rates completes the experimental results. As a conclusion, it is recommended to test SPT notched specimens in environment at very slow rates, of around E-6 mm/s, when characterizing in Hydrogen Embrittlement (HE) scenarios, in order to allow the interaction material-environment to govern the process

On the global economic potentials and marginal costs of non-renewable resources and the price of energy commodities

A model is presented in this work for simulating endogenously the evolution of the marginal costs of production of energy carriers from non-renewable resources, their consumption, depletion pathways and timescales. Such marginal costs can be used to simulate the long term average price formation of energy commodities. Drawing on previous work where a global database of energy resource economic potentials was constructed, this work uses cost distributions of non-renewable resources in order to evaluate global flows of energy commodities. A mathematical framework is given to calculate endogenous flows of energy resources given an exogenous commodity price path. This framework can be used in reverse in order to calculate an exogenous marginal cost of production of energy carriers given an exogenous carrier demand. Using rigid price inelastic assumptions independent of the economy, these two approaches generate limiting scenarios that depict extreme use of natural resources. This is useful to characterise the current state and possible uses of remaining non-renewable resources such as fossil fuels and natural uranium. The theory is however designed for use within economic or technology models that allow technology substitutions. In this work, it is implemented in the global power sector model FTT:Power. Policy implications are given.Comment: 18 pages, 7 figures, 8 pages of supplementary informatio