Investigating simultaneous microwave dielectric and structural characterisation of heterogeneous gas sorption processes

The main aim of this thesis is to design, simulate, build, and conduct and interpret experiments using simultaneous microwave dielectric and structural measurements. These measurements will be used to characterise solid state materials during polar gas sorption processes. The gases reviewed in this thesis are ammonia and sulphur dioxide. Metal-organic frameworks are investigated for use as both ammonia and sulphur dioxide solid state storage materials. Metal halides are also investigated for absorption of ammonia. These sorption processes are investigated using microwave dielectric characterisation. This is combined with structural characterisation from either neutron or X-ray diffraction. The combination of these techniques is used to monitor changes in bulk material properties along with changes in molecular structure during the gas sorption processes. A sample environment is designed for simultaneous neutron diffraction and microwave characterisation of materials at varying temperatures. The developed equipment uses heating coils to heat a flowing gas, which is used to heat the sample. A cylindrical cavity is designed and constructed for this experimental rig with a thinned section of cavity wall to minimise neutron scattering from the sample environment. This equipment is tested by successfully monitoring the activation of a MOF sample at 150 °C to remove water present in the sample. A hairpin style resonator is also developed for use with simultaneous dielectric characterisation and Xray diffraction. The open structure of the hairpin geometry of this resonator allows the X-ray beam to be unimpeded by the resonator, maximising the resolution or X-ray data. This is used to investigate the absorption of ammonia by halides salts. Also in this thesis, a new method for correcting for changes in frequency caused by changes in temperature is developed for cylindrical microwave cavities. Temperature correction is often required during microwave characterisation where changes in temperature caused by changes in ambient conditions, exothermic/endothermic reactions, or while examining dielectric properties over a range of temperatures. TMm10 modes consist of two symmetrical mode patterns with identical resonant frequencies. This technique uses a strategically placed sample to split vi the frequencies of these degenerate modes. The higher frequency, unperturbed mode is used as a local reference and the lower frequency, perturbed mode as the measurement mode. The effectiveness of this technique is proved by heating water sample from 20 ºC to 60 ºC, calculating its permittivity and comparing against literature values

Submission to consultation about 10-year Adult Literacy, Numeracy and Digital Literacy (ALND) Strategy for Ireland From The Department of Adult and Community Education, Maynooth University

The Department of Adult and Community Education, Maynooth University, warmly welcome the development of the 10-year Adult Literacy, Numeracy and Digital Literacy (ALND) Strategy for Ireland to support the development of a sustained, long-term vision to enhance literacy, numeracy and digital literacy capabilities. As the only university academic Dept. of Adult and Community Education in Ireland, our work is informed by the insights and pedagogical practices of the adult and further educators with whom we work to enhance their professional development. We are also guided by our learning from the extensive research on adult education we have conducted over the decades with a range of community, national and international partners. In this submission we draw on this learning to highlight elements which we feel will create a learning environment where all adults in Ireland will have the necessary literacy, numeracy and digital literacy capabilities to fully participate in society. We welcome the inclusive nature of this strategy in enhancing social, economic, political and cultural equality for all peoples as well as critically reflecting on the opportunities and challenges inherent in it

Achievement of combined goals of low-density lipoprotein cholesterol and non-high-density lipoprotein cholesterol with three different statins: Results from VOYAGER

AbstractBackgroundGuidelines suggest that the combination of low-density lipoprotein cholesterol (LDL-C) and non-high-density lipoprotein cholesterol (non-HDL-C) is the most clinically relevant goal for lipid-lowering treatments.MethodsData from VOYAGER, an individual patient data meta-analysis including 32,258 patients from 37 clinical trials, was used to determine the percentage of patients reaching combined goals of LDL-C and non-HDL-C following treatment with simvastatin, atorvastatin, or rosuvastatin. Paired comparisons were made between each dose of rosuvastatin and the same or higher doses of simvastatin and atorvastatin.ResultsEach dose of rosuvastatin brought significantly more patients to the combined goal of LDL-C < 100 mg/dL and non-HDL-C < 130 mg/dL than the same or double dose of atorvastatin; atorvastatin 80 mg was significantly superior to rosuvastatin 10 mg (all p < 0.001). Each dose of rosuvastatin helped significantly more patients reach the combined goal than any dose of simvastatin (all p < 0.001), except for rosuvastatin 10 mg versus simvastatin 80 mg (non-significant). Also, each dose of rosuvastatin helped significantly more patients to reach the combined goal of LDL-C < 70 mg/dL and non-HDL-C < 100 mg/dL than the same or double dose of atorvastatin (all p < 0.001). Every dose of rosuvastatin was significantly superior to all doses of simvastatin (all p ≤ 0.020), except for rosuvastatin 10 mg versus simvastatin 40 mg and 80 mg (non-significant).ConclusionsPhysicians' choice of statin and dose is important in helping patients achieve the combined LDL-C and non-HDL-C goals recommended in established guidelines

Submission to the independent review of the Student Grant Scheme by The Department of Further and Higher Education, Research, Innovation and Science Department of Adult and Community Education, Maynooth University

The Department of Adult and Community Education, Maynooth University, welcome this opportunity to contribute to the consultation for the independent review of the Student Grant Scheme by The Department of Further and Higher Education, Research, Innovation and Science. Based on consultation with staff and students in our department, we present key discussion points and recommendations below about the current SUSI eligibility criteria and grant support, the potential impact of changing income thresholds and of widening the supports to include part time provision, postgraduate programme, FET learners and blended/online provision. Since its establishment in 1974, the Department of Adult and Community Education (DACE) in Maynooth University has focused on meeting the educational needs of diverse groups in our society, supporting the transformation of lives and communities through adult and community education to create a just, equitable and sustainable society. Our work is informed by the experiences of students and staff of the department through programmes ranging from outreach certificates and diplomas, undergraduate and post-graduate programmes to thousands of students from diverse backgrounds on campus and across outreach centres nationally over the past 40 years. Our work is set within a broader context where Maynooth University welcomes students from diverse backgrounds, including having approximately half of its 1st year full-time undergraduate new entrants in receipt of a student grant, the highest proportion of students in receipt of a grant in the University sector (HEA 2015, 2017). We consulted with staff and students in our department to explore their experiences and opinions on the student award system, including those in receipt of SUSI and those who are not currently eligible. We also consulted with the Communiversity Network of community based adult education coordinators and adult guidance services who are advocates for lifelong learning among the most disadvantaged groups. The document that follows is informed by the insights provided by these students, staff and community actors. In particular, we wish to highlight issues about current income thresholds and the costs of higher education; diverse student pathways and knowledge about progression; and the rationale and impacts of widening the supports to include part time provision, postgraduate programme, FET learners and blended/online provision

The influence of solvent composition on the coordination environment of the Co/Mn/Br based para-xylene oxidation catalyst as revealed by EPR and ESEEM spectroscopy

The industrially important para-xylene oxidation reaction, based on a Co/Mn/Br catalyst, operates in a water/acetic acid (H2O/AcOH) solvent system. The correct H2O/AcOH ratio of the solvent is crucial in controlling the reaction yields and selectivities. However, the influence of this variable solvent system on the catalyst structure and coordination environment is not well understood. Using UV-vis spectroscopy, we observed the formation of tetrahedral Co2+ species when the solvent composition was below 10 wt% H2O. These were considered to be tetrahedral Co2+ species with either 2 or 3 coordinating Br− ligands. The pronounced CW EPR linewidth changes observed in the Mn2+ signals revealed a strong correlation on the solvent H2O content. Detailed analysis revealed that these variations in the linewidth were attributed to the changing coordination sphere around the Mn2+ centres, with a maximum linewidth occurring at 8–10 wt% H2O. The narrow linewidths below 8 wt% H2O were found to result from substitution of H2O/AcOH ligands by Br, whereas above 8 wt% H2O a further narrowing of the linewidth was actually caused by greater amounts of H2O coordination. To confirm this, 3-pulse ESEEM measurements on the Mn2+ were conducted in the solvent compositions corresponding to 3, 8, 13.7 and 20 wt% H2O. The results showed a marked change in the number (n) of coordinated H2O molecules (ranging from n = 0, 0, 1.0 to 4.0 respectively for the 3–20 wt% H2O content). For the first time, these findings provide a crucial insight into the relationship between solvent composition and catalyst structure in this industrially important catalytic reaction

A novel dual mode X-band EPR resonator for rapid in situ microwave heating

A unique dual mode X-band CW EPR resonator designed for simultaneous EPR measurement and rapid MW induced sample heating is described. Chemical reactions subjected to a flow of energy and matter can be perturbed away from the thermodynamic equilibrium by imposing a rapid shock or physical change to the system. Depending on the magnitude of the perturbation, these changes can dictate the subsequent evolution of the entire system, allowing for instance to populate non-equilibrium reactive intermediate states. Temperature jump (T-jump) experiments are a common method to achieve such perturbations. Most T-jump experiments are based on Joule Heating methods or IR lasers. Here we demonstrate the principle of rapid sample heating based on microwaves. The benefits of MW heating include i) rapid and efficient heating (i.e. using a tuned resonant cavity, 99% efficient power transfer to the sample can be achieved), and ii) volumetric heating (i.e. the entire sample volume rises in temperature at once, since heat is generated in the sample instead of being transferred to it). Accordingly, the key concept of the design is the use of a cavity resonator allowing EPR detection (at 9.5 GHz) and sample heating (at 6.1 GHz). Temperature enhancements of 50 °C within a few seconds are possible. This is evidenced and illustrated here by probing the temperature-induced variation of the rotational dynamics of 16-doxyl stearic acid methyl ester (16-DSE) spin probe grafted on the surface of sodium dodecyl sulphate (SDS) micelles in water, as well as copper (II) acetylacetonate in chloroform. Rapid changes in the rotational dynamics of the paramagnetic centres provide direct evidence for the in situ and simultaneous EPR measurement-heating capabilities of the resonator. Improvements afforded by the use of pulsed MW sources, will enable faster heating time scales to be achieved. In the longer term, this current study demonstrates the simple and direct possibilities for using MW heating as a means of performing T-jump experiments

Simultaneous neutron powder diffraction and microwave dielectric studies of ammonia absorption in metal-organic framework systems

Thanks to EPSRC for funding Michael Barter and to STFC ISIS Neutron and Muon Spallation facility for funding Michael Barter and for funding this research. RSF thanks the Royal Society for receipt of a University Research Fellowship, and the University of Glasgow for funding.Ammonia absorption has been investigated in metal-organic frameworks (UiO-67, HKUST-1 and CPO-27-Co) using custom-built apparatus that allows simultaneous neutron powder diffraction (NPD), microwave dielectric characterisation and out-gas mass spectroscopy of solid-state materials during ammonia adsorption. Deuterated ammonia was flowed through the sample and absorption monitored using mass flow meters and mass spectroscopy. Argon gas was then flowed through the ammoniated sample to cause ammonia desorption. Changes in structure found from NPD measurements were compared to changes in dielectric characteristics to differentiate physisorbed and metal-coordinated ammonia, as well as determine decomposition of sample materials. The results of these studies allow the identification of materials with useful ammonia storage properties and provides a new metric for the measurement of gas absorption within mesoporous solids.Publisher PDFPeer reviewe

Design considerations of a dual mode X-band EPR resonator for rapid in-situ microwave heating

This paper describes the design considerations for a dual mode X-band continuous wave (CW) Electron Paramagnetic Resonance (EPR) cavity, for simultaneous EPR measurement and microwave heating of the same sample. An elliptical cavity geometry is chosen to split the degeneracy of the TM110 mode, allowing for a well resolved EPR signal with the TM110,a and TM110,b modes resonating at around 10 GHz and 9.5 GHz, respectively, the latter of which is used for EPR measurements. This geometry has the benefit that the TM010 mode used for microwave heating resonates at 6.1 GHz, below the cut off frequency of the X-band waveguide used for the EPR channel, providing effective isolation between the heating and EPR channels. The use of a pair of 9 µm thick copper clad laminates as the flat cavity walls allows for sufficient penetration of the modulation field (Bmod) into the cavity, as well as maintaining a high cavity Q factor (> 5700) for sensitive EPR measurements. Locating the heating port at an angle of 135° to the EPR port provides additional space for easier coupling adjustment and for larger sample access to be accommodated. The associated decrease of EPR signal strength is fully compensated for by using a 7.2 GHz low pass filter on the heating port. EPR spectra using 1.6 mm and 4.0 mm sample tubes are shown at room temperature (298 K) and 318 K for a standard Cu(acac)2 solution, demonstrating the effectiveness of this dual-mode EPR cavity for microwave heating during EPR detection

The Genome of C57BL/6J Eve , the Mother of the Laboratory Mouse Genome Reference Strain.

Isogenic laboratory mouse strains enhance reproducibility because individual animals are genetically identical. For the most widely used isogenic strain, C57BL/6, there exists a wealth of genetic, phenotypic, and genomic data, including a high-quality reference genome (GRCm38.p6). Now 20 years after the first release of the mouse reference genome, C57BL/6J mice are at least 26 inbreeding generations removed from GRCm38 and the strain is now maintained with periodic reintroduction of cryorecovered mice derived from a single breeder pair, aptly named Adam and Eve. To provide an update to the mouse reference genome that more accurately represents the genome of today\u27s C57BL/6J mice, we took advantage of long read, short read, and optical mapping technologies to generate a de novo assembly of the C57BL/6J Eve genome (B6Eve). Using these data, we have addressed recurring variants observed in previous mouse genomic studies. We have also identified structural variations, closed gaps in the mouse reference assembly, and revealed previously unannotated coding sequences. This B6Eve assembly explains discrepant observations that have been associated with GRCm38-based analyses, and will inform a reference genome that is more representative of the C57BL/6J mice that are in use today