Microstructure modification of EB-pvd gadolinium zirconate thermal barrier coatings and the effect on their resistance against siliceous CMAS melts

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Art and the Environment

Excerpt: On June 15, 2017, my students and I found ourselves dancing to the beat of native instruments, played by Leo Emmanuel Castro and his associates at Sanghabi, an organization that promotes indigenous Filipino culture. We were each holding a bungkaka, beating it against the palm of our hands, as we participated in Leo’s panghinalay, a prayer ritual that drives away evil spirits and at the same time gives thanks to the divine as it gathers together disparate people into a community. My students and I were having fun, getting into the rhythm of the gong and the bamboo xylophone, swaying our hips and waving our arms in the air. The others in the group were more inhibited, perhaps uncomfortable with the unconventional prayer. Or maybe because it felt very strange for them to be participating in such a pagan ritual, especially because we were in The Museum, on the opening day of the last show for this year

Molecular and physiologial insights into diatom ecology : enviromental risks and potential applications

福井県立大学Fukui Prefectural University博士（生物資源学）2024doctoral thesi

Atlantic overturning in decline?

Global ocean circulation is an important factor in climate variability and change. In particular, changes in the strength of the Atlantic meridional overturning circulation (AMOC) have been implicated in ancient climate events, as well as in recent climate anomalies such as the rapid warming of the North Atlantic Ocean in the mid-1990s. A series of moored current meters and temperature sensors deployed in the Atlantic at 26° N known as the RAPID-MOCHA array has been used to monitor the strength of meridional overturning since 2004. The data indicate a decline in this strength over the period 2004–20123. Here, using additional observations and climate model simulations we suggest that this measured decline is not merely a short-term fluctuation, but is part of a substantial reduction in meridional overturning occurring on a decadal timescale

Hybrid HVDC circuit breaker with self-powered gate drives

The ever increasing electric power demand and the advent of renewable energy sources have revived the interest in high-voltage direct current (HVDC) multi-terminal networks. However, the absence of a suitable circuit breaker or fault tolerant VSC station topologies with the required characteristics (such as operating speed) have, until recently, been an obstacle in the development of large scale multi-terminal networks for HVDC. This paper presents a hybrid HVDC circuit breaker concept which is capable of meeting the requirements of HVDC networks. Simulation results are presented which are validated by experimental results taken from a 2.5kV, 700A rated laboratory prototype

Mechanisms of decadal variability in the Labrador Sea and the wider North Atlantic in a high-resolution climate model

A necessary step before assessing the performance of decadal predictions is the evaluation of the processes that bring memory to the climate system, both in climate models and observations. These mechanisms are particularly relevant in the North Atlantic, where the ocean circulation, related to both the Subpolar Gyre and the Meridional Overturning Circulation (AMOC), is thought to be important for driving significant heat content anomalies. Recently, a rapid decline in observed densities in the deep Labrador Sea has pointed to an ongoing slowdown of the AMOC strength taking place since the mid 90s, a decline also hinted by in-situ observations from the RAPID array. This study explores the use of Labrador Sea densities as a precursor of the ocean circulation changes, by analysing a 300-year long simulation with the state-of-the-art coupled model HadGEM3-GC2. The major drivers of Labrador Sea density variability are investigated, and are characterised by three major contributions. First, the integrated effect of local surface heat fluxes, mainly driven by year-to-year changes in the North Atlantic Oscillation, which accounts for 62% of the total variance. Additionally, two multidecadal-to-centennial contributions from the Greenland-Scotland Ridge outflows are quantified; the first associated with freshwater exports via the East Greenland Current, and the second with density changes in the Denmark Strait Overflow. Finally, evidence is shown that decadal trends in Labrador Sea densities are followed by important atmospheric impacts. In particular, a negative winter NAO response appears to follow the positive Labrador Sea density trends, and provides a phase reversal mechanism

The Role of Secondary Airports for Today's Low-Cost Carrier Business Models: The European Case

One of the core characteristics of Low-Cost Carriers (LCCs) is their use of secondary and regional airports. However, nothing is fixed as the market constantly evolves and carriers modify their strategies in order to achieve growth. This paper uses the examples of Ryanair, easyJet and Norwegian to show how changes to LCC business models are affecting secondary airports across Europe. Using a content analysis, this paper first describes how airport choice factors for LCCs have evolved over the last 10 years. This is followed by a data analysis of historical and current airline network capacity to identify how LCC traffic at secondary airports is developing. The paper finds that cost, demand and efficiency are still the most important criteria for LCCs when choosing an airport to operate from. However, it also identifies that LCCs have become more interested in serving business passengers, which is why they are increasingly using primary airports (accounting for 58% of their recent capacity growth). Through the use of a selection of case airports it is finally concluded that the evolution of LCCs increases competition between primary and secondary gateways. In most cases, secondary airports are losing a significant amount of LCC traffic and only sustain flights to less important destinations. This research puts into question the future importance of secondary airports for LCCs. As not all airports have been impacted by the hybridisation of LCCs to the same extent, the results are not equally applicable to the whole European airport industry

Identifying uncertainties in Arctic climate change projections

Wide ranging climate changes are expected in the Arctic by the end of the 21st century, but projections of the size of these changes vary widely across current global climate models. This variation represents a large source of uncertainty in our understanding of the evolution of Arctic climate. Here we systematically quantify and assess the model uncertainty in Arctic climate changes in two CO2 doubling experiments: a multimodel ensemble (CMIP3) and an ensemble constructed using a single model (HadCM3) with multiple parameter perturbations (THC-QUMP). These two ensembles allow us to assess the contribution that both structural and parameter variations across models make to the total uncertainty and to begin to attribute sources of uncertainty in projected changes. We find that parameter uncertainty is an major source of uncertainty in certain aspects of Arctic climate. But also that uncertainties in the mean climate state in the 20th century, most notably in the northward Atlantic ocean heat transport and Arctic sea ice volume, are a significant source of uncertainty for projections of future Arctic change. We suggest that better observational constraints on these quantities will lead to significant improvements in the precision of projections of future Arctic climate change

Beyond the Bump: Reconceiving the Philosophy of Pregnancy

French philosopher Hélène Cixous (1976) stressed the importance of feminine writing. She believes that women should take part in sharing their experiences from their own novel points-of-view. We discuss that while pregnancy is an experience unique to women; it has been misappropriated by patriarchal structures throughout the years. The pregnancy bump; which is more than just evidence of the uterus stretching to accommodate the fetus; is a symbol of a woman\u27s triumphs and struggles all throughout conception; pregnancy and childbirth. We show that women have already gone beyond the bump and challenged existing patriarchal systems through different means; as Cixous has enjoined women to do. With this; it is asserted that the philosophy of pregnancy be reconceived as well; in order to escape existing boundaries that constrict the discourse to ethical issues of rape; abortion; and medical interventions; making it face issues that surround women\u27s experience of pregnancy; as well as deeper meanings the pregnant body itself represents

Possible causes of data model discrepancy in the temperature history of the last Millennium

Model simulations and proxy-based reconstructions are the main tools for quantifying pre-instrumental climate variations. For some metrics such as Northern Hemisphere mean temperatures, there is remarkable agreement between models and reconstructions. For other diagnostics, such as the regional response to volcanic eruptions, or hemispheric temperature differences, substantial disagreements between data and models have been reported. Here, we assess the potential sources of these discrepancies by comparing 1000-year hemispheric temperature reconstructions based on real-world paleoclimate proxies with climate-model-based pseudoproxies. These pseudoproxy experiments (PPE) indicate that noise inherent in proxy records and the unequal spatial distribution of proxy data are the key factors in explaining the data-model differences. For example, lower inter-hemispheric correlations in reconstructions can be fully accounted for by these factors in the PPE. Noise and data sampling also partly explain the reduced amplitude of the response to external forcing in reconstructions compared to models. For other metrics, such as inter-hemispheric differences, some, although reduced, discrepancy remains. Our results suggest that improving proxy data quality and spatial coverage is the key factor to increase the quality of future climate reconstructions, while the total number of proxy records and reconstruction methodology play a smaller role