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Hysteretic current mode control of a wide output voltage three-level converter
No full textMulti-level dc-dc converters can offer very high efficiency but have been generally limited to voltage mode control schemes for wide output voltage applications due to difficulties with current mode control near certain duty-cycles. For applications that require current mode control, this paper proposes a hysteretic current mode control scheme which allows cycle-by-cycle control of multi-level converters over a wide duty-cycle range while also allowing operation at the critical duty-cycles found in multi-level converters. This enables high-efficiency solutions for applications that require a wide range of tightly regulated outputs like capacitor & battery charging, direct laser diode driving and motor control. This is achieved using a multi-mode control scheme with ramped current references, a maximum interval timer and reference offsetting for flying capacitor balancing. This control scheme is verified in Simulink modelling and implemented on a prototype three-level buck converter using a combination of a low-cost Field Programmable Gate Array and discrete analog circuitry. Alternative implementations are also described.Research Ireland, in collaboration with Advanced Energy and the University of Galway (Grant Number: EBPPG/2020/280)peer-reviewe
Development and evaluation of novel technologies to reduce methane emissions focusing on forage based ruminant production systems
No full textEnteric methane, a by-product of feed fermentation in the rumen, accounts for 44.3% of global agricultural greenhouse gas emissions. The agricultural sector is facing increasing pressure due to the need to increase food production to meet the demands of the growing population while meeting the greenhouse gas reduction targets which have been written into legally binding climate agreements. Hence, mitigation of enteric methane from ruminant livestock is now a key research focus. Dietary manipulation through the incorporation of anti-methanogenic compounds in ruminant diets has been the most widely researched and effective strategy to-date. However, the majority of the research has been reliant on offering the anti-methanogenic compound mixed into the animal’s total mixed ration. Considering that grassland and mixed systems account for 97% of global enteric methane emissions, there is a necessity to develop anti-methanogenic strategies that are applicable to predominantly forage-based systems. Seaweeds containing bromoform have consistently reduced methane production in vitro and in vivo. However, there are unresolved concerns regarding animal health and the environment with bromoform supplementation. Therefore, the first objective of this thesis was to screen a range of non-bromoform containing seaweeds in vitro for their effects on methane production and digestibility, using the rumen simulation technique system. None of the seaweeds assessed reduced methane production (Chapter 3). Subsequently, following further in vitro studies which are not presented within this thesis, a range of promising anti-methanogenic compounds were applied in vivo, in sheep (Chapter 4) and beef cattle (Chapter 5 and 6), mixed with concentrate feed and supplemented once or twice daily, respectively. Methane production was measured using portable accumulation chambers and GreenFeed technology, in sheep and beef, respectively. While brown seaweed, Ascophyllum nodosum, failed to reduce methane production in vivo (Chapter 4 and 5), isolating the anti-methanogenic agent (phlorotannins) and offering an Ascophyllum nodosum extract to sheep (Chapter 4) and beef cattle (Chapter 5), reduced methane production by 9 and 8%, respectively. Oils high in polyunsaturated fatty acids, soya oil and linseed oil, were offered to sheep (Chapter 4) and beef cattle (Chapter 5), respectively, resulting in reductions in methane production of 9 and 19%. Finally, calcium peroxide was offered to beef cattle in Chapter 6, reducing methane production by 18 and 28% at a low and a high dose, respectively. Some anti-methanogenic compounds lose their potency if subjected to processing, i.e. formulated into a pelleted feed, which is useful for delivering a homogenous feed to ruminants. Therefore, calcium peroxide was incorporated into both a coarse ration and a pellet to evaluate its processability, resulting in a 28 and 27% reduction in methane production, respectively, when offered twice daily. Surplus to the environmental effects of the compounds, the effects of the diets on animal health and performance, ruminal fermentation and diet digestibility were investigated. Essential oils and soya oil offered to sheep in Chapter 4 were the only compounds assessed that had a positive effect on animal performance. Linseed oil and calcium peroxide increased propionate production in Chapter 5 and 6, respectively. Additionally, calcium peroxide reduced total tract digestibility, which did not result in a reduction in performance. In Chapter 5, microbial DNA was extracted from rumen samples from beef cattle supplemented with linseed oil and the Ascophyllum nodosum extract. The rumen microbiome was sequenced using a metataxonomic approach to investigate the effects on microbial communities (bacteria, archaea, fungi and protozoa), resulting in subtle shifts in bacterial and fungal communities for linseed supplemented animals. The work of this thesis will contribute significantly to the continued development of anti-methanogenic dietary strategies focussing on application at pasture, with the aim of extracting the most effective anti-methanogenic agents and incorporating them in a slow-release bolus to reduce reliance on concentrate supplementation.Funding - Department of Agriculture, Food and the Marine (DAFM RSF 2019R479) Teagasc Walsh Scholarship (WS2019229
Digital twin with soft actor-critic reinforcement learning for transitioning from Industry 4.0 to 5.0
No full textIndustry 5.0 builds on the foundations of Industry 4.0 and ensures the transition to a sustainable, flexible, and human-centric workplace. The transition from Industry 4.0 to Industry 5.0 addresses important limitations of traditional automation, such as limited flexibility, human-machine collaboration. Industry 5.0 seeks to overcome these issues through evolution, with an emphasis on sustainability, resilience, and human-centric interactions. However, these changes come with challenges related to real-time adaptation and optimal resource allocation in dynamic industrial environments. To facilitate this transition, we propose a Digital Twin (DT) system that employs a Soft Actor-Critic (SAC) , which is a reinforcement learning algorithm. This integration enhances adaptability in real-time, efficient resource allocation, and flexibility in dynamic industrial environments. The SAC-DT algorithm is evaluated using three main scenarios: demand change management, real-time control under uncertain conditions, and optimization of performance. These scenarios demonstrate how the SAC-DT increases productivity, adaptability, reliability, energy efficiency, and reduced downtime. The proposed scheme is compared with baseline models which include DRL-DRP and GCNN-DRL. The analyses show that the SAC-DT scheme yields better productivity, flexibility and, resource utilization efficiency, thus highlighting the applicability of this proposed scheme as valuable to move closer to Industry 5.0 that will guarantee solid, reliable, pragmatic, sustainable technological implementations that meet industrial goals and requirements in future.peer-reviewe
Léargas ar stádas na Gaeilge i gceantair éagsúla i gContae na Mí de réir Dhaonáireamh 1911
No full textBaineann an t-alt seo le cás na teanga i gContae na Mí. Úsáidtear Daonáireamh 1911 le léargas a fháil ar athróga a bhaineann le ceist teanga ag am ríthábhachtach ag tús an 20ú haois. Baineann ceisteanna socheolaíochta, ceisteanna reiligiúin agus ceisteanna faoin oideachas leis seo. Roghnaíodh bailte fearainn randamacha agus iniúchtar na teaghlaigh iontu. I mórán cásanna tá an breithiúnas déanta cheana féin i dtaobh cúrsaí teanga. Déantar taighde uaireanta ‘to test a judgement already made’ (Neuman, 2000: 159). Ní hionann an scéal i ngach contae.peer-reviewe
Win ratio analysis of the LANDMARK trial
No full textThe LANDMARK trial reported the non-inferiority of the Myval transcatheter heart valve (THV) series compared with the contemporary standard THV series (Sapien and Evolut) for a 30-day composite endpoint in patients with severe aortic stenosis. This exploratory study compared the performance of the Myval THV series with the contemporary THV series using the win ratio analysis.LANDMARK trial is funded by Meril Life Sciences.peer-reviewe
Léirmheas ar an Ghaeilge sa dlí le Dáithí Mac Cárthaigh
No full textIs iniúchadh atá sa leabhar An Ghaeilge sa Dlí le Dáithí Mac Cárthaigh ar stádas na Gaeilge in Éirinn de réir an dlí. Déantar cur síos ar an reachtaíocht agus ar an gcásdlí a bhaineann leis an nGaeilge go stairiúil agus sa lá atá inniu ann. D’fhoilsigh Leabhar Breac sa bhliain 2020 é, agus mar sin rithfeadh cúpla bearna leis an léitheoir, mar shampla, Acht na dTeangacha Oifigiúla (Leasú) 2021 chomh maith leis an Acht Féiniúlachta agus Teanga (Tuaisceart Éireann) 2022. Mar abhcóide é féin, éiríonn leis an údar leagan amach soiléir, loighciúil a chur i bhfeidhm ar an ábhar. Leanann an leabhar forbairt stádas na Gaeilge ó bhunú an tSaorstáit go dtí an lá atá inniu ann, dírithe ar phleanáil teanga agus na státseirbhísí.peer-reviewe
Investigating the role of heavy metals in the environment as a selective pressure for the dissemination of antimicrobial resistance
No full textAntimicrobial resistance (AMR) is a growing concern globally. The ability of microorganisms to survive in the presence of antimicrobials and the spread of antimicrobial resistance genes (ARGs) pose a significant risk to human, animal and environmental health. The environment's impact on the emergence and spread of AMR is increasingly acknowledged as critical, with reservoirs like soil and water playing a key role in the persistence and dissemination of antimicrobial-resistant bacteria (ARB) and ARGs. In this regard, the primary food production environment is of considerable importance due to the significant potential of ARB and ARGs to be transmitted to humans and animals through the food chain. Extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-PE) and carbapenem resistant Enterobacterales (CRE) have been recognised by the World Health Organization as critical priority pathogens due to the severe infections they can cause, which are difficult to treat and often require last-resort treatments. Therefore, the surveillance of these bacteria in the environment is fundamental to tackle AMR. Beyond antimicrobials, also other factors, such as heavy metals and biocides, influence AMR. Several mechanisms underlie the association between heavy metals and AMR, including co-resistance, cross-resistance, co-regulation and biofilm formation. Therefore, the aim of this research was to investigate the role of heavy metals, in particular zinc, as a selective pressure for antimicrobial resistant Enterobacterales’ occurrence and dissemination in the primary food production environment. Firstly, a scoping review was conducted to identify the knowledge gaps in this area (Chapter Two). A total of 73 studies undertaken over a period from 2008 and 2021 were included, the majority of which were conducted in China. The main environmental samples analysed in these studies were soil, water and manure, collected from different settings, including areas with natural occurrence of heavy metals, areas intentionally amended with heavy metals, and areas close to mines or industries that might release heavy metals. The results underlined the link between heavy metals and AMR, with particular focus on the role of mobile genetic elements (MGEs) in the dissemination of ARGs and heavy metal resistance genes (MRGs). Following this, a research study was performed to assess the presence and characteristics of antimicrobial resistant Enterobacterales in soil and spinach samples with and without zinc soil amendment (Chapter Three). A total of 160 samples (soil, n = 92, spinach, n = 68) were collected from two different locations, where some of the soil plots were amended with zinc sulphate and other plots were used as control. A total of 20 antimicrobial resistant Enterobacterales were isolated, with Serratia fonticola species being the most common (n=16). None of the isolates were resistant to three or more antimicrobials. Genes encoding antimicrobial resistance and genes encoding zinc resistance were identified. However, a direct correlation between zinc amendment of soils and AMR was not identified. A follow on research study was conducted to evaluate the occurrence of antimicrobial resistant Enterobacterales in dairy production (Chapter Four). Fifty soil samples and 29 bovine milk filters were collected from ten different farms (five farms from two different geographical regions in Ireland with low and high zinc concentrations). A total of 40 antimicrobial resistant Enterobacterales were identified, with Escherichia coli the most predominant species. Phenotypic analysis identified 17 multidrug resistant (MDR) isolates, including ten E. coli isolates collected from the high zinc containing region, and seven MDR out of nine isolates from milk filters. Genotypic analysis identified ARGs and MRGs among the isolates collected from the high zinc containing region; however, no direct correlation between zinc resistance genes and AMR was observed. The advantage of using milk filters for AMR monitoring in dairy production, which allows early detection of ARB before entering the food chain, was recognised. Finally, a metagenomic study on ten composite soil samples and 18 milk filters, collected as part of the research detailed in Chapter Four, was performed to acquire a better understanding of the AMR presence in dairy production in high and low zinc containing regions (Chapter Five). This study identified the dominant microbial communities in both sample types, as well as the diverse profile of ARGs and MRGs present in the different sample types. Overall, this body of work demonstrates that the primary food production environment can harbour clinically relevant Enterobacterales, serving as a significant reservoir and transmission source of AMR. This highlights the critical need of monitoring strategies to address the spread of AMR within the food chain, to which humans and animals may be exposed, and protect public health. Milk filters provide an ideal opportunity for the surveillance of AMR in dairy production. Although a direct correlation between zinc and AMR occurrence was not observed in the studies undertaken, the potential role of other heavy metals, such as copper, was suggested. Further investigation is needed to understand the impact of other heavy metals on AMR dynamics in the primary food production environment
A systematic review on the utility of wastewater surveillance for monitoring yellow fever virus and other arboviruses
No full textAims
This review aims to examine wastewater surveillance for the detection of yellow fever virus (YFV) and related arboviruses, focusing on concentration and extraction methodology, viral decay kinetics, and quantification techniques.
Methods
A literature search was conducted across 5 databases: PubMed, Science Direct, Web of Science, Embase, and Google Scholar following the PRISMA guidelines. Studies included were original scientific articles published between April 2014 and April 2024. Human research studies investigating wastewater surveillance and YFV or other arboviruses/flaviviruses were assessed.
Results
A total of 17 studies were included in this review. YFV was not detected in population-based wastewater samples; however, successful detection of similar viruses suggests potential for YFV monitoring with wastewater surveillance. YFV-spiked wastewater studies reveal similar concentration efficiency and decay rates between arboviruses. Effective concentration methods for YFV likely include centrifugation ultrafiltration and solid pellet extraction. YFV and arboviruses decay faster at higher temperatures, though YFV remains detectable for several days at these temperatures.
Conclusions
Wastewater surveillance presents a promising approach for monitoring YFV and other arboviruses. However, further research is needed to overcome existing limitations and enhance its effectiveness.This review was supported by Applied Microbiology International Summer Studentship Grant 2024 (Grant reference no.: 02-303952).peer-reviewe
Serial quantitative optical coherence tomography for luminal volume changes following either paclitaxel or sirolimus coated balloon in de novo small coronary artery lesions
No full textBackground
Drug coated balloons (DCB) are a treatment option for lesions in small coronary arteries, with treatment using paclitaxel coated balloons (PCB) associated with less angiographic late lumen loss than sirolimus coated balloons (SCB).
Methods
This single-center sub-study of the TRANSFORM-I study compared quantitative optical coherence tomography (OCT) data in patients with de novo lesions in small coronary arteries treated with the MagicTouch (SCB) or SeQuent Please Neo (PCB). The relationship between the lumen volume of the treated segment immediately post procedure and at 6-month follow-up was evaluated. Late lumen volume loss (LLVL, mm3) was defined as the post-procedural lumen volume – lumen volume at 6 months.
Results
Serial OCT analysis was performed in 19 patients with 21 lesions (SCB: 9 patients/11 lesions; PCB: 10 patients/10 lesions). There was a significant decrease in lumen volume between post-procedure and 6 months in the SCB group (97.35 ± 71.09 mm3 vs 87.96 ± 61.48 mm3, p = 0.03), but not in the PCB group (69.67 ± 38.24 mm3 vs 71.64 ± 42.22 mm3, p = 0.64). The LLVL was 9.39 ± 12.76 mm3 and − 1.97 ± 12.90 mm3 in the SCB and PCB group, respectively (SCB vs PCB, p = 0.06). A trend for interaction between SCB and PCB was observed in the relationship between dissection volume and LLVL (SCB: LLVL = 1.28 ∗ dissection volume + 7.42, p = 0.37; PCB: LLVL = −2.84 ∗ dissection volume + 4.51, p = 0.12; p for interaction = 0.07).
Conclusion
In de novo lesions of small coronary arteries, treatment with an SCB lead to a significant decrease in lumen volume at 6-months compared to post-procedure, with no significant change observed after treatment with a PCB.TRANSFORM trial was funded by Concept Medical.peer-reviewe