Gamma-ray spectrometry across the Upper Devonian basin succession at Kowala in the Holy Cross Mountains (Poland)

The Upper Devonian sequence at Kowala in the Holy Cross Mountains was logged using gamma-ray spectrometry, for investigating the changes of oxygenation level in the Late Devonian basin. The Th/U ratio indicates that oxygen levels were low throughout the Late Frasnian interval, with low peaks during the Kellwasser Events showing anoxic conditions in the basin. The F-F boundary interval was also oxygen deficient, but there may have been a brief reoxygenation at the boundary itself. By the Famennian crepida Zone, the basin gradually began to reoxygenate, but in the trachytera Zone another anoxic event, the Annulata Event occurred, causing a bloom rather than extinction of specially adapted taxa such as Guerichia. Thus the gamma-ray spectrometry data suggests that basinal anoxia prevailed through much of the Late Frasnian. The F-F extinction might have been the result of prolonged stresses imposed on the ecosystem, particularly during the euxinic Upper Kellwasser Event

Gamma-ray spectrometry across the Upper Devonian basin succession at Kowala in the Holy Cross Mountains (Poland)

The Upper Devonian sequence at Kowala in the Holy Cross Mountains was logged using gamma-ray spectrometry, for investigating the changes of oxygenation level in the Late Devonian basin. The Th/U ratio indicates that oxygen levels were low throughout the Late Frasnian interval, with low peaks during the Kellwasser Events showing anoxic conditions in the basin. The F-F boundary interval was also oxygen deficient, but there may have been a brief reoxygenation at the boundary itself. By the Famennian crepida Zone, the basin gradually began to reoxygenate, but in the trachytera Zone another anoxic event, the Annulata Event occurred, causing a bloom rather than extinction of specially adapted taxa such as Guerichia. Thus the gamma-ray spectrometry data suggests that basinal anoxia prevailed through much of the Late Frasnian. The F-F extinction might have been the result of prolonged stresses imposed on the ecosystem, particularly during the euxinic Upper Kellwasser Event

Empleo de aditivos en la fabricación de materiales

De los múltiples materiales de construcción utilizados, el cemento Portland es con diferencia el más u sado . Deb ido a esto, es uno de los materiales sobre los que se ha efectuado un mayor volumen de investigación, tanto en comportamiento mecánico como químico . Sin embargo, estos estudios se centran sobre todo en el cemento portland gris, dejando de lado otro tipo de cemento como el blanco. Por ello, en aras de aumentar el conocimiento existente sobre el comportamiento de cemento blanco, este Trabajo de Fin de Master propone llevar a cabo dos fases experimentales diferenciadas, sobre cómo afecta a una serie de pastas formadas por cemento blanco, la adición de aditivos colorantes y superfluidificantes a base de policarboxilatos. Para ello, por una parte, se realiza una caracterización microestructural a edades de 7 y 28 días, por medio de espectrografía infrarroja y an álisis por difracción de rayos X. Con el objetivo de comprobar si la adición de pigmentos amarillo y verde a dosificaciones de 1%, 3%, 5% y 15% afectan al proceso de hidratación del cemento. De la misma manera a estas pastas se les añadirá un 1% de superf luidificante, junto con una reducción de agua. Por otro lado, se estudiará el efecto que tienen estos aditivos en la trabajabilidad de las pastas, este análisis se realizará estudiando las características reológicas . La composición de las pastas a analiza r, será la misma que en la fase anterior, solo que se añadirá una dosificación de cemento adicional (10%). A modo de conclusiones, se observa, que el uso de estos aditivos no causa cambios significativos en el proceso de hidratación de las pastas, más all á de producir ligeros retrasos en la hidratación de algunos compuestos. En cuanto a la trabajabilidad, se determina que a grandes dosificaciones de aditivos colorantes, la afectación a las propiedades reológicas de las pastas es notable, debido sobre todo a la absorción del agua por parte de los pigmentos

Molecular Recognition via Hydrogen Bonding in Supramolecular Complexes : A Fourier Transform Infrared Spectroscopy Study

A.M.F. and D.Z. would like to acknowledge the School of Engineering (University of Aberdeen) for funding. M.P., L.O. and A.M.-F. would like to acknowledge the Spanish Ministry of Science for the MAT2017-84838-P project. Acknowledgments: A.M.-F. and F.B. would like to thank Euan Bain and Brian Paterson for their assistance during some experiments (University of Aberdeen).Peer reviewedPublisher PD

Photo-driven effects in twist-bend nematic phases : dynamic and memory response of liquid crystalline dimers

AMF would like to acknowledge the Scottish Government and the Royal Society of Edinburgh, for the award of one SAPHIRE project, the Carnegie Trust for the Universities of Scotland, for the award of the RIG008586 project, the Royal Society, for the Research Grant RGS\R1\201397, and the Royal Society of Chemistry, for the award of the mobility grant M19-0000. AMF and AK would also like to acknowledge the Carnegie Trust for the Universities of Scotland, for the award of one Carnegie Trust Vacation Scholarships. All authors would like to thank the School of Engineering and the Department of Chemistry of the University of Aberdeen, for financial support.Peer reviewedPostprin

Dicationic stilbazolium salts : structural, thermal, optical, and ionic conduction properties

Acknowledgments This research is in part supported by the NSF EPSCoR RING-TRUE III grant no. 0447416, NSF-SBIR grant no. OII-0610753, NSF-STTR grant no. IIP-0740289 and NASA GRC contract no. NNX10CD25P (PKB). BD and BH thank the CNRS and University of Strasbourg. AMF would like to acknowledge the Carnegie Trust for the Universities of Scotland, for the Research Incentive Grant RIG008586, the Royal Society and Specac Ltd., for the Research Grant RGS\R1\201397, the Royal Society of Chemistry for the award of a mobility grant (M19-0000), and the Royal Society of Edinburgh and the Scottish Government, for the award of a SAPHIRE project.Peer reviewedPostprin

Ionically conducting and photoresponsive liquid crystalline terpolymers : towards multifunctional polymer electrolytes

ARG and AMF thank the financial support of the Generalitat Valenciana, through the Grisolia and Forteza programs, and the Spanish Ministry of Science and Innovation, through the Research Projects ENE2007-67584-C03 and UPOVCE-3E-013 and the awarding of two FPI and FPU pre-doctoral grants. AMF and NFKA would like to thank the Royal Academy of Engineering for the award of the Newton Research Collaboration Programme grant NRCP1516/4/61. AMF acknowledges the School of Engineering of the University of Aberdeen for financial support.Peer reviewedPostprin

Ionically conducting and photoresponsive liquid crystalline terpolymers: Towards multifunctional polymer electrolytes

[EN] We have prepared a series of new ionically conducting polymer electrolytes consisting of side-chain liquid crystal terpolymers with mesogenic azobenzenes, sulfonic acid groups and methyl methacrylate. The poly[10-(4-methoxyazobenzene -4'-oxy)decyl methacrylate] -co-poly[2-acrylamido-2-methyl-1-propanesulfonic acid]-copoly [methyl methacrylate]s, 10-MeOAzB/AMPS/MMA terpolymers, were synthesised by a one-pot conventional radical polymerisation. All samples were characterised by NMR, GPC/SEC, FT-IR, POM, XRD, DSC, UV-visible spectrophotometry and EIS. The terpolymers have light responsive properties, and exhibit liquid crystallinity over a wide range of compositions. Above a certain threshold of AMPS content, the 10-MeOAzB/AMPS/MMA terpolymers exhibit ionic conductivities in the 10(-8)-10(-4)S.cm(-1) range, with signs of decoupling of ionic mobility from segmental motions of the polymer.ARG and AMF thank the financial support of the Generalitat Valenciana, through the Grisolia and Forteza programs, and the Spanish Ministry of Science and Innovation, through the Research Projects ENE2007-67584-C03 and UPOVCE-3E-013 and the awarding of two FPI and FPU pre-doctoral grants. AMF and NFKA would like to thank the Royal Academy of Engineering for the award of the Newton Research Collaboration Programme grant NRCP1516/4/61. AMF acknowledges the School of Engineering of the University of Aberdeen for financial support.Vanti, L.; Alauddin, SM.; Zaton, D.; Aripin, N.; Giaccinti-Baschetti, M.; Imrie, C.; Ribes-Greus, A.... (2018). Ionically conducting and photoresponsive liquid crystalline terpolymers: Towards multifunctional polymer electrolytes. European Polymer Journal. 109:124-132. https://doi.org/10.1016/j.eurpolymj.2018.08.033S12413210

Bent-core liquid crystals joining the ethylene-oxide/lithium ion tandem: Ionic conductivity and dielectric response towards new electrolytes for energy applications

We report the dielectric and conductivity response of three materials containing bent-core and tetra(ethylene-oxide) moieties, and their complexes doped with lithium triflate salts, as new potential nanostructured electrolytes. Whilst the pristine bent-core compounds do not show mesomorphism, the doped materials display smectic mesophases inside indium tin oxide cells assisted by the selective solvation of the lithium ions in the ethylene-oxide blocks. The dielectric response of the materials in the high-frequency range is controlled by the chemical composition of the bent-core structure, and the presence of lithium ions promotes direct current conductivity at low frequencies, in the σdc ∼ 10-5 S cm−1 range, which can be enhanced to σdc ∼ 10-4 S cm−1 via trans-to-cis photoisomerization of azobenzene groups. The dynamic and dual character of these materials (responding to low and high frequency electrical fields), the formation of ferroelectric crystals capable to store energy, and their interactions with light, will be applied to develop new energy devices