Effect of Zr additions on thermal stability of Al-Cu precipitates in as-cast and cold worked samples

While Zr is frequently added to Al alloys to control grain size with the formation of large (\u3e1 μm) primary precipitates, little research has been conducted on the effect of nanoscale Al3Zr precipitates on Al alloys. By comparing the precipitation and corresponding strength evolution between Al-Cu-Zr alloys with different Zr concentrations, the effects of Zr on Al-Cu precipitation with and without primary Al3Zr precipitates can be observed. In the absence of these large precipitates, all Al3Zr phases can be formed, through high temperature aging treatments, as a dispersion of nanoprecipaites inside the Al grains. In this study, Al-Cu-Zr ternary alloys were produced and heat treated to determine whether an increase in the coarsening resistance of Al-Cu precipitate phases would be observed with a distribution of the more thermally stable Al3Zr nanoprecipitates. Generally, properly aged Al-Cu alloys will coarsen when encountering elevated temperatures higher than ~473 K (~200 °C). Diluted Al-Zr alloys (\u3c0.07 at % Zr) resist coarsening behavior until the significantly higher temperatures of ~673 K (~400 °C), but are comparatively limited in strength because of a limited solubility of Zr in the Al matrix. Hardness testing and transmission electron microscope (TEM) results are discussed, in which it is found that even very small additions of Zr, when properly accounted for during heat treating, produce a finer microstructure and higher strength than in similar Al-Cu binary alloys. No significant change in the thermal stability of strengthening was observed, indicating that the finer precipitate microstructure is resultant from a higher nucleation density, as opposed to a decrease in coarsening behavior

How much wind energy will be curtailed on the 2020 Irish power system?

This paper describes a model of the 2020 Irish electricity system which was developed and solved in a mixed integer programming, unit commitment and economic dispatch tool called PLEXOS. The model includes all generators on the island of Ireland, a simplified representation of the neighbouring British system including proposed wind capacity and interconnectors between the two systems. The level of wind curtailment is determined under varying levels of three influencing factors. The first factor is the amount of offshore wind, the second is the allowed limit of system non-synchronous penetration (SNSP) and the third is inclusion or exclusion of transmission constraints. A binding constraint, resulting from the 2020 EU renewable energy targets, is that 37% of generation comes from wind. When the SNSP limit was increased from 60% to 75% there was a reduction in wind curtailment from 14% to 7%, with a further reduction when the proportion of wind capacity installed offshore was increased. Wind curtailment in the range of SNSP limit of 70-100% is influenced primarily by the inclusion of transmission constraints. Large changes in the dispatch of conventional generators were also evident due to the imposition of SNSP limits and transmission constraints

Climate policy, interconnection and carbon leakage: the effect of unilateral UK policy on electricity and GHG emissions in Ireland. ESRI WP458. June 2013

This paper examines the effect on Ireland’s Single Electricity Market (SEM) of the UK’s unilateral policy to implement a carbon price floor for electricity generation based on fossil-fuel. We simulate electricity markets and find that, subject to efficient use of the interconnectors between the two markets, a carbon price floor will lead to carbon leakage, with associated emissions in the Republic of Ireland increasing by 8% and SEM’s electricity prices increasing by 2.4%. As the carbon price floor does not affect the number of ETS allowances no change is anticipated in aggregate European emissions. We also find that the EU’s proposal to postpone ETS allowance auctions will reduce Irish emissions somewhat but that the trade opportunities associated with the UK carbon price floor means that emissions reductions in Ireland will be lower than might have been otherwise. A carbon price floor will result in substantial tax revenues and had the carbon price floor been implemented in Northern Ireland the larger share of taxes remitted would be paid by Republic of Ireland customers within the SEM. A carbon price floor in the Republic of Ireland is a potential policy option that would generate revenues in excess of €250 million but associated electricity prices increases in excess of 17% would have significant negative welfare and competitiveness effects

Climate Policy, Interconnection and Carbon Leakage: The Effect of Unilateral UK Policy on Electricity and GHG Emissions in Ireland. ESRI Research Bulletin 2014/1/7

We analyse the effect of the carbon price floor (CPF) implemented by the UK in April 2013 using a simulation model, PLEXOS, of the Irish (SEM) and British (BETTA) electricity markets. The paper illustrates that unilateral climate policies have the potential to cause perverse outcomes through carbon leakage. Even though Northern Ireland is exempt from the CPF in recognition of energy security issues, our work finds that BETTA’s CPF has the potential to have significant spill-over into the SEM due to the interconnection between the SEM and the BETTA markets

Climate Policy, Interconnection and Carbon Leakage: The Effect of Unilateral UK Policy on Electricity and GHG Emissions in Ireland. ESRI Research Bulletin 2014/1/7

We analyse the effect of the carbon price floor (CPF) implemented by the UK in April 2013 using a simulation model, PLEXOS, of the Irish (SEM) and British (BETTA) electricity markets. The paper illustrates that unilateral climate policies have the potential to cause perverse outcomes through carbon leakage. Even though Northern Ireland is exempt from the CPF in recognition of energy security issues, our work finds that BETTA’s CPF has the potential to have significant spill-over into the SEM due to the interconnection between the SEM and the BETTA markets

At, by, to, and past: An Essay in Multimodal Image Theory

Proceedings of the Nineteenth Annual Meeting of the Berkeley Linguistics Society: General Session and Parasession on Semantic Typology and Semantic Universals (1993

English Possessives, Topicality, and the Silverstein Hierarchy

Proceedings of the Thirteenth Annual Meeting of the Berkeley Linguistics Society (1987), pp. 65-7

The Effects of Freezing on Faecal Microbiota as Determined Using MiSeq Sequencing and Culture-Based Investigations

peer-reviewedBackground High-throughput sequencing has enabled detailed insights into complex microbial environments, including the human gut microbiota. The accuracy of the sequencing data however, is reliant upon appropriate storage of the samples prior to DNA extraction. The aim of this study was to conduct the first MiSeq sequencing investigation into the effects of faecal storage on the microbiota, compared to fresh samples. Culture-based analysis was also completed. Methods Seven faecal samples were collected from healthy adults. Samples were separated into fresh (DNA extracted immediately), snap frozen on dry ice and frozen for 7 days at -80°C prior to DNA extraction or samples frozen at -80°C for 7 days before DNA extraction. Sequencing was completed on the Illumina MiSeq platform. Culturing of total aerobes, anaerobes and bifidobacteria was also completed. Results No significant differences at phylum or family levels between the treatment groups occurred. At genus level only Faecalibacterium and Leuconostoc were significantly different in the fresh samples compared to the snap frozen group (p = 0.0298; p = 0.0330 respectively). Diversity analysis indicated that samples clustered based on the individual donor, rather than by storage group. No significant differences occurred in the culture-based analysis between the fresh, snap or -80°C frozen samples. Conclusions Using the MiSeq platform coupled with culture-based analysis, this study highlighted that limited significant changes in microbiota occur following rapid freezing of faecal samples prior to DNA extraction. Thus, rapid freezing of samples prior to DNA extraction and culturing, preserves the integrity of the microbiota.Jennifer Deane is in receipt of a Teagasc Walsh Fellowship. The authors and their work were supported by the Science Foundation Ireland and funded by the Centre for Science, Engineering and Technology (SFI-CSET) grant 02/CE/B124 and by FP7 funded CFMATTERS (Cystic Fibrosis Microbiome-determined Antibiotic Therapy Trial in Exacerbations: Results Stratified, Grant Agreement no. 603038). The Alimentary Pharmabiotic Centre is a research centre funded by Science Foundation Ireland (SFI). This publication has emanated from research supported in part by a research grant from Science Foundation Ireland (SFI) under Grant Number SFI/12/RC/2273