214 research outputs found
Reliability and resilience evaluation of distribution automation.
Modern distribution grid utilities are steadily adapting to the concepts of Smart Grids by
augmenting distribution grids with Distribution Automation (DA) to enhance visibility
and control for the purpose of enhanced system availability. Existing methods to place
and evaluate DA overlook the important enhancement it provides to the resilience of a
system. Resilience, a much-discussed but poorly defined measure for power systems,
represents a system’s ability to withstand and recover from High-Impact Low-Probability
(HILP) events such as storms and earthquakes. This thesis argues that exisiting resilience
quantification methods do not capture the direct contribution which DA can make
to enhance system resilience. It develops a novel model and methodology to analyse
distribution grid resilience using the formalisms of Reliability Graphs (RGs), and
Stochastic Reward Nets (SRNs). These two models capture the different parts of the
complex recovery process which distribution grids perform to recover from faults using
DA.
There are three novel contributions in this thesis. Firstly, a three-tier hierarchical
model which contains an RG is developed to assess the enhancement which DA equipment
provides to load point and feeder availability and resilience. Next, and SRN is used to
develop a load point (LP) model which incorporates the dependence of feeder assets
during the fault isolation phase of the recovery process. Finally, the SRN model is
augmented with a phased recovery model to represent the complex recovery process
for distribution grids. Utilising these models, the placement of switch automation and
fault indicators is evaluated, and the contribution they make to resilience demonstrated.
Collectively, these models give a novel means of assessing the the availability, sensitivity
and resilience of distribution grids which utilise DA
Aggregating multiple body sensors for analysis in sports
Real time monitoring of the wellness of sportspersons, during their sporting activity and training, is important in order to maximise performance during the sporting event itself and during training, as well as being important for the health of the sportsperson overall. We have combined a suite of common, off-the-shelf sensors with specialist body sensing technology we are developing ourselves and constructed a software system for recording, analysing and presenting sensed data gathered from a single player during a sporting activity, a football match. We gather readings for heart rate, galvanic skin response, motion, heat flux, respiration, and location (GPS) using on-body sensors, while simultaneously tracking player activity using a combination of a playercam video and pitch-wide video recording. We have aggregated all this sensed data into a single overview of player performance and activity which can be reviewed, post-event. We are currently working on integrating other non-invasive methods for real-time on-body monitoring of sweat electrolytes and pH via a textile-based sweat sampling and analysis platform. Our work is heading in two directions; firstly from post-event data aggregation to real-time monitoring, and secondly, to convert raw sensor readings into performance indicators that are meaningful to practitioners in the field
Avian Resistance to Campylobacter jejuni Colonization Is Associated with an Intestinal Immunogene Expression Signature Identified by mRNA Sequencing
peer-reviewedThis research was funded by the The Irish Department of Agriculture and Food’s Food Institutional Research Measure (http://www.agriculture.gov.ie/
research/foodinstitutionalresearchmeasurefirm) – Grant No: 06_RDD_486.Campylobacter jejuni is the most common cause of human bacterial gastroenteritis and is associated with several post-infectious manifestations, including onset of the autoimmune neuropathy Guillain-Barré syndrome, causing significant morbidity and mortality. Poorly-cooked chicken meat is the most frequent source of infection as C. jejuni colonizes the avian intestine in a commensal relationship. However, not all chickens are equally colonized and resistance seems to be genetically determined. We hypothesize that differences in immune response may contribute to variation in colonization levels between susceptible and resistant birds. Using high-throughput sequencing in an avian infection model, we investigate gene expression associated with resistance or susceptibility to colonization of the gastrointestinal tract with C. jejuni and find that gut related immune mechanisms are critical for regulating colonization. Amongst a single population of 300 4-week old chickens, there was clear segregation in levels of C. jejuni colonization 48 hours post-exposure. RNAseq analysis of caecal tissue from 14 C. jejuni-susceptible and 14 C. jejuni-resistant birds generated over 363 million short mRNA sequences which were investigated to identify 219 differentially expressed genes. Significantly higher expression of genes involved in the innate immune response, cytokine signaling, B cell and T cell activation and immunoglobulin production, as well as the renin-angiotensin system was observed in resistant birds, suggesting an early active immune response to C. jejuni. Lower expression of these genes in colonized birds suggests suppression or inhibition of a clearing immune response thus facilitating commensal colonization and generating vectors for zoonotic transmission. This study describes biological processes regulating C. jejuni colonization of the avian intestine and gives insight into the differential immune mechanisms incited in response to commensal bacteria in general within vertebrate populations. The results reported here illustrate how an exaggerated immune response may be elicited in a subset of the population, which alters host-microbe interactions and inhibits the commensal state, therefore having wider relevance with regard to inflammatory and autoimmune disease
Sodium naphthalene-2,6-dicarboxylate : an anode for sodium batteries
We thank the EPSRC (EP/K025112/1) and the Leverhulme Trust (RPG-2016-323) for funding and Diamond Light Source for rapid access to synchrotron radiation facilities.The conjugated dicarboxylate, sodium naphthalene-2,6-dicarboxylate (Na2NDC), has been prepared by a low energy consumption reflux method and its performance as a negative electrode for sodium-ion batteries evaluated in electrochemical cells. The structure of Na2NDC was solved for the first time (monoclinic P21/c) from powder X-ray diffraction data and consists of π-stacked naphthalene units separated by sodium-oxygen layers. Through an appropriate choice of binder and conducting carbon additive Na2NDC exhibits a reversible two electron sodium insertion at around 0.4 V vs. Na+/Na with remarkably stable capacities of ca. 200 mA h g-1 at a rate of C/2 and good rate capability (~133 mA h g-1 at 5C). In parallel the high thermal stability of the material is demonstrated by HT-X-ray diffraction, the framework remaining intact to above 500 °C.PostprintPeer reviewe
Design of the VLT-CUBES image slicers: Field re-formatters to provide two spectral resolutions
CUBES is a high efficiency spectrograph designed for a Cassegrain focus of the Very Large Telescope and is expected to be in operation in 2028. It is designed to observe point or compact sources in a spectral range from 300 to 405nm. CUBES will provide two spectral resolving powers: R≥20,000 for high resolution (HR) and R≥5,000 for low resolution (LR). This is achieved by using an image slicer for each resolution mode. The image slicers re-format a rectangular on-sky field of view of either 1.5arcsec by 10arcsec (HR) or 6arcsec by 10arcsec (LR) into six side-by-side slitlets which form the spectrograph slit. The slit dimensions are 0.19mm × 88mm for HR and 0.77mm × 88mm for LR. The on-sky and physical widths of the slicer mirrors are 0.25arcsec/0.5mm (HR) and 1arcsec/2mm (LR). The image slicers reduce the spectrograph entrance slit etendue and hence the size of the spectrograph optics without associated slit losses. Each of the proposed image slicers consists of two arrays of six spherical mirrors (slicer mirror and camera mirror arrays) which provide a straight entrance slit to the spectrograph with almost diffraction-limited optical quality. This paper presents the description of the image slicers at the end of the Phase A conceptual design, including their optical design and expected performance
Antibody Response to Pneumocystis jirovecii: Antibody Response to Pneumocystis jirovecii Major Surface Glycoprotein
We conducted a prospective pilot study of the serologic responses to overlapping recombinant fragments of the Pneumocystis jirovecii major surface glycoprotein (Msg) in HIV-infected patients with pneumonia due to P. jirovecii and other causes. Similar baseline geometric mean antibody levels to the fragments measured by an ELISA were found in both groups. Serum antibodies to MsgC in P. jirovecii patients rose to a peak level 3–4 weeks (p<0.001) after recovery from pneumocystosis; baseline CD4+ count >50 cells/μL and first episode of pneumocystosis were the principal host factors associated with this rise (both p<0.001). Thus, MsgC shows promise as a serologic reagent and should be tested further in clinical and epidemiologic studies
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