26 research outputs found
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
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
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
AMF would like to thank Ivan Dominguez-Candela for his support during the ferroelectric measurements.Peer reviewedPublisher PD
Middle Jurassic cyclostome bryozoans from the Polish Jura
New collections of bryozoans from the Middle Jurassic (Late Bajocian and Bathonian) of Poland add significantly to our knowledge of the diversity and biogeography of the Cyclostomata at a time when they were the dominant bryozoan order in the fossil record. A total of 16 species and one form−genus (“Berenicea”) are present. Most are encrusters, predominantly on hiatus concretions. A single erect species was found in deposits interpreted as regurgitates of a marine vertebrate. The following new species are described: Microeciella annae sp. nov., M. kuklinskii sp. nov., M. maleckii sp. nov., M. mokrskoensis sp. nov., M. magnopora sp. nov., Reptomultisparsa harae sp. nov., and Hyporosopora bugajensis sp. nov. The taxonomic importance of the morphology of both the gonozooids and pseudopores is underlined, especially for encrusting species of the “Berenicea” type that are otherwise difficult to distinguish from one another. The described bryozoan assemblage encrusting hiatus concretions from the Polish Middle Jurassic is the richest that has been documented globally from this kind of substrate
In quest of cyrtocrinid origins: Evidence from Late Triassic ossicles from the Tatra Mountains
We report cyrtocrinid (Crinoidea) ossicles from the Rhaetian (Late Triassic) of the Tatra Mountains (southern Poland). The columnals are high, the facets are covered with thick crenulae and the latera are concave. Such features of symplectial articulation and latera distinguish them from the columnals of other Triassic crinoids (i.e., millericrinids and encrinids) and therefore we consider they belong to Cyrtocrinida. The oldest representatives of cyrtocrinids were known from the Early Jurassic, therefore the presented material constitutes the oldest world record of these crinoids to date. We speculate that perturbations related to the global mid−Carnian extinction combined with predation intensity observed in the Middle– Late Triassic have been involved in early origin of Cyrtocrinida
Comment on "Palaeoenvironmental control on distribution of crinoids in the Bathonian (Middle Jurassic) of England and France" by Aaron W. Hunter and Charlie J. Underwood
Late Cretaceous gastropod egg capsules from the Netherlands preserved by bioimmuration
Clusters of gastropod egg capsules, inferred to be of neritoids
and attached to the inner shell wall of the ultimate whorl of a
large volutid gastropod, are here recorded from the upper
Nekum Member (Maastricht Formation; late Maastrichtian)
of the ENCI−Heidelberg Cement Group quarry, St Pietersberg (Maastricht, southeast Netherlands). Because the aragonitic shell of the volutid has dissolved, the outlines of the egg
capsules are now revealed on the steinkern of indurated biocalcarenite, having been subsequently overgrown by cheilostome bryozoan colonies and preserved as mould bioimmurations. This represents the first example of gastropod eggs preserved through bioimmuration, as well as the first record of
gastropod eggs from the Cretaceous