Structure-Property Relationships for Electron-Vibrational Coupling in Conjugated Organic Oligomeric Systems

A series of ð-conjugated oligomers containing one to six monomer units were studied by absorption and photoluminescence spectroscopy. As is common for these systems, a linear relationship between the positioning of the lowest-energy absorption and the highest-energy photoluminescence maxima plotted versus inverse conjugation length is observed, in good agreement with a simple nearly free electron model, one of the earliest descriptions of the properties of one-dimensional organic molecules. It was observed that the Stokes shift and therefore Huang-Rhys factor also exhibit a well-defined relationship with increasing conjugation length, implying a correlation between the electron-vibrational coupling and chain length. This correlation is further examined using Raman spectroscopy, whereby the integrated relative Raman scattering is seen to behave superlinearly with chain length. The Stokes shift and the Raman activity are also well-correlated in these systems. There is a clear indication that the vibrational activity and thus nonradiative decay processes are controllable through molecular structure

Solution to the problem of the poor cyclic fatigue resistance of bulk metallic glasses

The recent development of metallic glass-matrix composites represents a particular milestone in engineering materials for structural applications owing to their remarkable combination of strength and toughness. However, metallic glasses are highly susceptible to cyclic fatigue damage, and previous attempts to solve this problem have been largely disappointing. Here, we propose and demonstrate a microstructural design strategy to overcome this limitation by matching the microstructural length scales (of the second phase) to mechanical crack-length scales. Specifically, semisolid processing is used to optimize the volume fraction, morphology, and size of second-phase dendrites to confine any initial deformation (shear banding) to the glassy regions separating dendrite arms having length scales of ≈2 μm, i.e., to less than the critical crack size for failure. Confinement of the damage to such interdendritic regions results in enhancement of fatigue lifetimes and increases the fatigue limit by an order of magnitude, making these “designed” composites as resistant to fatigue damage as high-strength steels and aluminum alloys. These design strategies can be universally applied to any other metallic glass systems

Historical Inquiry into the Construction of Religion as a School Subject for Catholic Schools in Australia

One of the most distinctive features of Catholic schools, both past and present, is their religious character. In Australia, as in many other parts of the world, the Catholic community invested significant energy developing and preserving this character. Central to this has been the teaching of Religion. Yet, from a historical perspective, there has been little effort undertaken to understand how Religion as a subject in Catholic schools has been constructed. This paper takes its lead from the latter observation. It is in three parts. First, the general historical background is outlined. Second, the importance of producing historical analyses of the construction of Religion as a subject for Catholic schools in the various Church jurisdictions in Australia is considered. This analysis is done through an exposition on the existing state of research within the broader corpus of knowledge to which studies of this type belong. The final part of the paper then indicates how one could go about providing a historical analysis of how Religion as a subject for Catholic schools in the various Church jurisdictions in Australia was constructed, particularly over the period 1929 to the present

Nanoscale density fluctuations in swift heavy ion irradiated amorphous SiO2

We report on the observation of nanoscale density fluctuations in 2 μm thick amorphous SiO₂ layers irradiated with 185 MeV Au ions. At high fluences, in excess of approximately 5 × 10¹² ions/cm², where the surface is completely covered by ion tracks, synchrotron small angle x-ray scattering measurements reveal the existence of a steady state of density fluctuations. In agreement with molecular dynamics simulations, this steady state is consistent with an ion track “annihilation” process, where high-density regions generated in the periphery of new tracks fill in low-density regions located at the center of existing tracks.The authors acknowledge the Australian Research Council and the Australian Synchrotron Research Program for financial support and thank the staff at the ANU Heavy Ion facility for their continued technical assistance. O.P., F.D., and K.N. acknowledge financial support from the Academy of Finland under its Centre of Excellence program as well as the OPNA project, and grants of computer capacity from CSC

The Potential of Vibrational Spectroscopy in the Early Detection of Cervical Cancer: an Exciting Emerging Field

The application of vibrational spectroscopy to disease diagnosis is a relatively new, rapidly evolving scientific field. Techniques such as Raman and infrared spectroscopy have shown great promise in this regard over the past number of years. This study directly compared Raman spectroscopy and synchrotron infrared (SR-IR) spectroscopy on parallel cervical cancer samples. Both frozen and dewaxed formalin fixed paraffin preserved tissue sections were examined. Both tissue types produced good quality Raman and SR-IR spectra, although the lesser processed, frozen tissue sections displayed the most detailed spectra. Spectroscopy was shown capable of discriminating between different cell types in normal cervical tissue. Spectra recorded from invasive carcinoma showed a marked difference from those recorded from normal cervical epithelial cells. Spectral differences identified with the onset of carcinogenesis include increased nucleic acid contributions and decreased glycogen levels. These investigations pave the way for an enlarged study into this exciting new diagnostic field

Geotechnical Performance of Suction Caisson Installation in Multi-layered Seabed Profiles

Suction caissons consist of large cylindrical buckets made from steel. In order to serve as foundations for various offshore structures, suction caissons are pushed into the seabed under pressure differential exerted on their lid by an imposed suction. Despite their wide use in the oil and gas industry, there are still some uncertainties regarding their installation process as a result of changes in seabed profiles such as the existence of low permeability layers as well as the variation in soil properties with depth (e.g. permeability decreasing with depth due to an increase in soil density). It is known that seepage conditions play a pivotal role in the installation process, particularly in sand. Indeed, pressure gradients generated by the imposed suction inside the caisson cavity cause an overall reduction in the soil resistance around the caisson wall and at caisson tip, thereby assisting the penetration into the seabed. Successful installation of caisson foundations relies on accurate prediction of soil conditions, in particular soil shear resistance during the installation. Existing knowledge of the prediction of soil conditions and required suction during caisson installation has some limitations which often resulted into rather conservative design methods. Most design procedures used to control suction during caisson installation assume an isotropic and homogenous seabed profile. Moreover, the actual variation of pressure gradient around the caisson wall at different penetration depths is often ignored, although it significantly affects soil resistance. Natural seabed can possess a heterogeneous property where it may comprise of different layers of soils including the presence of layers with low-permeability i.e. clay or silt. In this paper, the effect of seepage on soil conditions during caisson installation is studied within the frame of the presence of a substratum that consists of silt. Suction induced seepage described throughout the installation process and its effects on frictional and tip resistance are considered. For this purpose, a numerical simulation is conducted on a normalised geometry of the suction caisson and surrounding soil, at different penetration depths. The distribution of pressure gradient on both inside and outside of the caisson wall is taken into consideration in both soil shear and tip resistance. Particular conclusions will be drawn on the implications of the presence of a low permeability silt layer on caisson installation

Institutional repositories:The HECA experience

This presentation was delivered by the HECA Research Group as part of the first HECA Research Conference that took place in November 2022. The HECA Research Group is comprised of Ann Byrne from Hibernia College, Tiernan O\u27 Sullivan from Dublin Business School and Debora Zorzi from CCT College in collaboration with Dimphne Ni Bhraonain from Griffith College. The presentation covers a range of topics related to institutional repositories, including setting up and maintaining a repository, copyright issues and the future of repositories.https://arc.cct.ie/fac_presentations/1008/thumbnail.jp

Vibrational Spectroscopic Studies to Elucidate the Structure of Water at Biological Interfaces

In biological systems, water takes up to 80% of the volume inside a cell. This water solubilizes the biological macromolecules such as the DNA, proteins and lipids. Recent advancements have shown that the water at the interface of a lipid membrane is structured, as five layers of structured water have been found at this solvent cage. Steady state Raman spectroscopy of water in lipids was performed in an attempt to elucidate the structure of water at the biological interface. Deuterium oxide (heavy water) was employed to hydrate lipid biomolecules. The heavier deuterium atom shifts the molecular vibrations and renders them distinct from conventional OH vibrations. Raman spectroscopy was used to probe the difficulties of observing the vibrational signature of the water molecule at low hydration limits. It was demonstrated that Raman can identify signatures of potential structured forms of water at the interface with lipid membranes

Increased hydrolysis by Thermomyces lanuginosus lipase for omega-3 fatty acids in the presence of a protic ionic liquid

We report that the hydrolytic performance of Thermomyces lanuginosus lipase, TLL, and its selectivity towards concentrating clinically important omega 3 fatty acids was increased by the addition of a protic ionic liquid, pIL, Triethylammonium mesylate, TeaMs. We show that TeaMs has a structure altering effect on TLL, changing both the secondary and tertiary structure of TLL. The thermal activity of TLL was also significantly enhanced by the addition of TeaMs.<br /