Diagnostics of Damages in Reinforced Concrete by the Parameters of Electric Response to Mechanical Impact

A method for non-destructive testing of reinforced concrete based on thephenomenon of mechano-electric transformations is proposed in this work. The procedure forassessing damage in concrete is based on the measurement of an electric response to a weakelastic impact. It was found that the moments of crack formation and growth during bendingare accompanied by a significant decrease in the correlation coefficient of the electricresponses spectra and by a stepwise change in spectrum shift (at frequency domain) at whichthe maximum correlation coefficient is observed. It was determined that the increase of energyattenuation coefficient of the electric response can serve as a forerunner of a catastrophicdestruction in concrete. The diagnostic criteria proposed in this work can be used formonitoring the damage processes in reinforced concrete under bending conditions

Electrochemical properties of composite fuel cell cathodes for La5.5WO12−δ proton conducting electrolytes

[EN] New composite cathodes for proton conducting solid oxide fuel cells (PC-SOFCs) based on the novel La5.5WO12-delta (LWO) electrolyte have been developed. First the applicability of LWO as a protonic electrolyte has been proved by recording the OCV in a Pt/LWO/Pt cell as a function of the temperature, matching the expected Nernst voltage. In order to improve the electrode performance on LWO PC-SOFCs, composite cathodes have been prepared by mixing the La0.8Sr0.2MnO3-delta (LSM) electronic phase with the LWO protonic phase. The ceramic-ceramic (cer-cer) composites have been electrochemically studied as cathodes on LWO dense electrolytes in symmetrical cells. Different ratios of both phases and two different electrode sintering temperatures (1050 and 1150 degrees C) have been studied. Electrochemical impedance spectroscopy (EIS) analysis has been carried out in the temperature range 700-900 degrees C under moist (2.5% H2O) atmospheres. Different oxygen partial pressures (pO(2)) have been employed in order to characterize the processes (surface reaction and charge transport) taking place at the composite cathode. A substantial improvement in the cathode performance has been attained by the addition of the LWO protonic phase into the LSM electronic material. From the electrochemical analysis it can be inferred that electrode enhancement is principally ascribed to the increase in the three-phase-boundary length, which enables electrochemical reactions to occur along the thickness of the electrode.Funding from European Union (FP7 Project EFFIPRO - Grant Agreement 227560), the Spanish Government (ENE2011-24761 and CSIC Intramural 200880I093 grants) is kindly acknowledged. The authors thank Dr M. Ivanova and Dr D. Sebold (Forschungszentrum Julich, IEK-1) for sample preparation for microscopy analysis, and Mrs M. Fabuel and Dr V. B. Vert for assistance in electrochemical tests.Solis Díaz, C.; Navarrete Algaba, L.; Roitsch, S.; Serra Alfaro, JM. (2012). Electrochemical properties of composite fuel cell cathodes for La5.5WO12−δ proton conducting electrolytes. Journal of Materials Chemistry. 22(31):16051-16059. https://doi.org/10.1039/c2jm32061d1605116059223

Fast track to nanomaterials: microwave assisted synthesis in ionic liquid media

Herein we present a general approach to metal and metal oxide nanoparticles using simple metal salts as starting materials. The reducing agent can be delivered in the form of the anion incorporated into the metal precursor respectively ionic liquid. Exemplary we demonstrate the synthesis of Cu and Ag as well as ZnO and NiO nanoparticles generated either from acetate or carbonate salts. All particles are synthesised by microwave heating without the necessity of inert conditions. Two different types of ionic liquids have been used as reaction media - tetra-n-butylphosphonium acetate (n-Bu4POAc) and 1-butyl-2,3-dimethylimidazolium N,N-bis(trifluoromethylsulfonyl)imid (bmmim NTf2). In this case, the choice of the ionic liquid seems to have significant influence on the size, shape and dispersity of the synthesised particles. It is clearly shown that the acetate anion present in all reaction mixtures can act as an inexpensive and nontoxic reducing agent. The final products in solid, liquid and gaseous phase have been characterised by XRD, TEM, NMR, FT-IR and online gas-phase MS

Improvement of transport properties and hydrogen permeation of chemically-stable proton conducting oxides bases on the system BaZr1-x-yYxMyO3-δ

[EN] The structural and transport properties as well as the chemical stability of a series of proton-conducting oxides based on yttrium-doped barium zirconate were investigated. Specifically, Pr-, Fe- and Mn-doped BaZr1-x-yYxMyO3-delta compounds were prepared by solid state reaction. The compound exhibiting the highest total and protonic conductivity at elevated temperatures under reducing atmospheres was BaZr0.8Y0.15Mn0.05O3-delta. Temperature-programmed reduction experiments revealed a particular redox behavior related to the Mn-species under selected conditions. The hydrogen permeation was thoroughly studied as a function of the temperature, hydrogen concentration and the humidification degree in the sweep gas. Moreover, the transient processes induced by alternate step changes in the humidification degree of the sweep gas were analysed. The highest steady hydrogen evolution flow exceeded 0.03 ml min(-1) cm(-2) (0.9 mm-thick membrane) at 1000 degrees C for the humidified sweep gas. The stability of BaZr0.8Y0.15M0.05O3-delta under operation-relevant atmospheres (CO2-rich reducing atmosphere at high temperature) was tested using different techniques ( X-ray diffraction (XRD), Raman, SEM, TEM and TG) and the results showed that this material is stable even when exposed to 115 ppm H2S.Financial support by the Spanish Ministry for Economics and Competitiveness (JAE-Pre 08-0058, ENE2008-06302 and ENE2011-24761 grants) and the Helmholtz Association of German Research Centers through the Helmholtz Alliance MEM-BRAIN (Initiative and Networking Fund) is kindly acknowledged. Dr M. Ivanova thanks the Northern European Innovative Energy Research Program N-INNER (grant no. 09- 064274) and the German Federal Ministry of Education and Research (BMBF) for supporting the N-INNER Project ‘‘Novel High Temperature Proton and Mixed-Proton Electron Conductors for Fuel Cells and H2-separation membranes’’ (Contract 03SF0330).Escolástico Rozalén, S.; Ivanova, M.; Solis Díaz, C.; Roitsch, S.; Meulenberg, WA.; Serra Alfaro, JM. (2012). Improvement of transport properties and hydrogen permeation of chemically-stable proton conducting oxides bases on the system BaZr1-x-yYxMyO3-δ. RSC Advances. 2(11):4932-4943. https://doi.org/10.1039/C2RA20214JS4932494321

Influence of the La6W2O15 Phase on the Properties and Integrity of La6-xWO12-x Based Membranes

The aim of the present work is to evaluate the influence of La6W2O15 secondary phase on the properties and integrity of La6-xWO12-δ–based membranes. Structural, microstructural and thermo–chemical study was carried out evidencing significant crystallographic and thermal expansion anisotropy: the reason for poor thermo–mechanical stability of La6W2O15. Conductivity of La6W2O15 was one to two orders of magnitude lower compared to the phase pure La6-xWO12-δ in the range of 300 to 900 °C. The relaxation study showed that the hydration process was faster for the La6W2O15 compared to the LWO phase, due to the higher electronic contribution to the total conductivity. Short–term stability tests in H2 at 900 °C and in a mixture of CO2 and CH4 at 750 °C were conducted and material remained stable. Remarkable reactivity with NiO and YSZ at elevated temperatures was further evidenced compared to the relative inert behavior towards MgO and CGO.Ivanova, ME.; Seeger, J.; Serra Alfaro, JM.; Solis Díaz, C.; Meulenberg, WA.; Fischer, W.; Roitsch, S.... (2012). Influence of the La6W2O15 Phase on the Properties and Integrity of La6-xWO12-x Based Membranes. Chemistry and Materials Research. 2(1):56-81. http://hdl.handle.net/10251/80837S56812

Specific characteristics of anti-neutrophil cytoplasmic antibodies in inflammatory bowel disease and detection of these antibodies by flow cytometry in a novel approach based on neutrophil extracellular traps

Hintergrund: Anti-Neutrophile zytoplasmatische Antikörper (ANCA) sind Autoantikörper, die sich gegen Bestandteile neutrophiler Granulozyten richten und an diversen entzündlichen Erkrankungen, wie beispielsweise primären Vaskulitiden kleiner Gefäße oder der Colitis Ulcerosa (CU), beteiligt sind. In der klinischen Standarddiagnostik wird das ANCA-Screening mit Hilfe indirekter Immunfluoreszenz auf Ethanol-fixierten neutrophilen Granulozyten durchgeführt. Eine besondere Herausforderung stellt die Detektion der atypischen ANCA der CU dar, da hier wahrscheinlich eine Vielzahl diverser Antigene an unterschiedlichen intrazellulären Lokalisationen unter funktioneller Beteiligung von Chromatin eine Rolle spielt. Es steht zur Diskussion, auf welchem Weg die granulären Proteine der neutrophilen Granulozyten im Körper zur immunologischen Präsentation verfügbar werden. In den letzten Jahren haben zahlreiche Studien gezeigt, dass neutrophile Granulozyten in der Lage sind, mit granulären Proteinen bestücktes Chromatin als neutrophile extrazelluläre Fallen (Neutrophil Extracellular Traps/NETs) auszustoßen. Hierdurch könnten mögliche granuläre und nukleäre ANCA-Antigene im extrazellulären Raum dem Immunsystem präsentiert werden. Ziele: Im Rahmen meiner Dissertation stellte ich die Hypothese auf, dass (I) ANCA-Immunoreaktivität auf NETs gefunden werden kann und (II) NETs als nützliches Hilfsmittel für eine neuartige Vorgehensweise in der ANCA-Diagnostik genutzt werden können. Methoden: Die verwendeten Seren stammten von Patienten, die entweder an einer ANCA-assoziierten Vaskulitis (n=10) oder Colitis Ulcerosa (n=30) erkrankt waren, beziehungsweise Patientenseren, die mit keiner diagnostizierten ANCA-assoziierten Erkrankung in Zusammenhang standen (n=20). Diese Seren wurden mit Hilfe indirekter Immunfluoreszenz auf Ethanol-fixierten neutrophilen Granulozyten und NETs untersucht. Darüber hinaus wurde eine neu entwickelte, durchflusszytometrische ANCA-Nachweismethode entwickelt und eingesetzt, die auf der Verwendung von zuvor mit NETs beschichteten Microbeads basierte. Ergebnisse und Beobachtungen: Auf Ethanol-fixierten NETs konnte eine spezifische ANCA-Bindung mit Hilfe von Immunfluoreszenz nachgewiesen werden. NETs tragen somit Zielantigene der ANCA. Des Weiteren wurde beobachtet, dass neutrophile Granulozyten NETs als Reaktion auf den Kontakt mit Microbeads bildeten und diese NETs an der Oberfläche der Beads haften blieben. Indem diese mit NETS-beschichteten Microbeads im Durchflusszytometer verwendet wurden, gelang es, pANCA, cANCA und aANCA zuverlässig in den getesteten Patientensera nachzuweisen. Die Antigene von CU-assoziierten, komplexen, DNase-1-sensiblen ANCA (NET-ANCA) wurden ebenfalls auf mit NETs beschichteten Microbeads erfasst. Schlussfolgerungen: Die Ergebnisse der Arbeit bestätigen, dass NETs ANCA-Antigene tragen und als Substrat in der ANCA-Detektion durch indirekte Immunfluoreszenz eingesetzt werden können. Darüber hinaus könnten mit NETs beschichtete Microbeads als neu entwickeltes Hilfsmittel für eine durchflusszytometrische ANCA-Screening Technik zu einem neuartigen kommerziellen Routinetest weiterentwickelt werden.Background: Anti-neutrophil-cytoplasmic antibodies (ANCA) are auto-antibodies directed against components of neutrophil granulocytes and may be found in various inflammatory conditions, like small-vessel vasculitis or ulcerative colitis (UC). Routine ANCA screening is performed on ethanol-fixed neutrophils using indirect immunofluorescence technique. Yet, how neutrophil granule proteins become available to immunologic presentation is a matter of debate. In recent years, various studies have shown that neutrophils are able to extrude their chromatin decorated with granular proteins as neutrophil extracelullar traps (NETs). Aim: This thesis aimed to show that (I) ANCA immunoreactivity may be found on NETs and (II) NETs may serve as a useful tool in a novel approach for ANCA detection. Methods: Sera from patients suffering from either ANCA-associated vasculitis (n = 10), UC (n = 30) or sera from patients without diagnosed ANCA-associated diseases (n = 20), respectively, were subjected to indirect immunofluorescence and a newly developed method to detect ANCA by flow cytometry employing microbead technology. Results: ANCA-related immunofluorescence was readily detectable on ethanol-fixed NETs, establishing NETs as a structure carrying ANCA target antigens. Moreover, we observed that neutrophils form NETs in response to microbeads and stick to the surface of these beads. Using these NET-coated microbeads in flow cytometry, we were capable of reliably detecting p-ANCA, c-ANCA, and a-ANCA in tested patient sera. UC-related complex DNase-1-sensitive ANCA (NET-ANCA) antigens were also detected on NET-coated microbeads. Conclusion: The results confirm that NETs carry ANCA target antigens and can be used as a substrate for ANCA detection using indirect immunofluorescence technique. Furthermore, NET-coated microbeads may be commercially developed as a novel tool for automated ANCA screening assays using flow cytometry

Microstructural and macroscopic aspects of the plasticity of complex metallic alloys

Complex metallic alloys (CMAs) represent a class of materials which are based on crystal structures with exceptionally large unit cells comprising up to more than a thousand atoms. As a result of the structural attributes of these phases, their plastic deformation behaviour features significant differences to conventional mechanisms known from structurally simple materials. In the present work, the plasticity of the three CMA phases, hexagonal μ-Al-Mn, body-centred cubic Mg$_{32}$(Al,Zn)$_{49}$, and face-centred cubic $\beta$-Al-Mg was investigated. Uniaxial deformation experiments on single crystalline samples of these alloys were carried out and thermodynamic activation parameters of the deformation processes were determined. Microstructural investigations by means of transmission electron microscopy (TEM) were carried out on μ-Al-Mn and Mg$_{32}$(Al,Zn)$_{49}$. The underlying deformation mechanisms of these phases were completely determined. Dislocation climb and associated diffusion of vacancies was found to play an essential role in the deformation processes of both materials

Covalent Hybrid Elastomers Based on Anisotropic Magnetic Nanoparticles and Elastic Polymers

Particle-filled elastomers are ubiquitous composite materials with applications ranging from durable materials, such as tires, to smart actuators and sensor materials. By employing magnetic nanoparticles as multifunctional, inorganic cross-linkers, PDMS-based hybrid elastomers with a novel unique architecture and a defined type of particle-matrix interaction are obtained-a direct covalent coupling between magnetic and elastic properties. The resulting particle-cross-linked elastomers possess application potential due to their defined magnetomechanical coupling and their large extensibility. As the filler phase, spindle-shaped hematite nanoparticles with a silica shell are used, and the swelling, thermal, magnetic, and mechanical properties of the resulting particle-cross-linked elastomers are systematically evaluated and compared to the properties of analogous yet conventionally cross-linked particle-filled elastomers of a similar composition. Some unique features are found for the hybrid elastomers, such as a large strain at break of up to epsilon(B) approximate to 1700%, that are attributed to the exceptional architecture, combining a well-integrated network of long polymer chains that are interconnected by network nodes with a high cross-linker functionality formed by the anisotropic magnetic nanoparticles

Detection by flow cytometry of anti-neutrophil cytoplasmic antibodies in a novel approach based on neutrophil extracellular traps

Background: Anti-neutrophil-cytoplasmic antibodies (ANCA) are auto-antibodies directed against components of neutrophil granulocytes and may be found in various inflammatory conditions, like small-vessel vasculitis or ulcerative colitis (UC). Routine ANCA screening is performed on ethanol-fixed neutrophils using indirect immunofluorescence technique. Yet, how neutrophil granule proteins become available to immunologic presentation is a matter of debate. In recent years, various studies have shown that neutrophils are able to extrude their chromatin decorated with granular proteins as neutrophil extracelullar traps (NETs). Aim: We hypothesized that (I) ANCA immunoreactivity may be found on NETs and (II) NETs may serve as a useful tool in a novel approach for ANCA detection. Methods: Sera from patients suffering from either ANCA-associated vasculitis (n = 10), UC (n = 30) or sera from patients without diagnosed ANCA-associated diseases (n = 20), respectively, were subjected to indirect immunofluorescence and a newly developed method to detect ANCA by flow cytometry employing microbead technology. Results: ANCA-related immunofluorescence was readily detectable on ethanol-fixed NETs, establishing NETs as a structure carrying ANCA target antigens. Moreover, we observed that neutrophils form NETs in response to microbeads and stick to the surface of these beads. Using these NET-coated microbeads in flow cytometry, we were capable of reliably detecting p-ANCA, c-ANCA, and a-ANCA in tested patient sera. UC-related complex DNase-1-sensitive ANCA (NET-ANCA) antigens were also detected on NET-coated microbeads. Conclusion: NET-coated microbeads may be commercially developed as a novel tool for automated ANCA screening assays using flow cytometry