Performance optimisation and productivity centre of excellence

As machines get larger and scientific applications advance, it is more and more imperative to fully utilize high performance computing (HPC) capability. The complexity and changing landscape of parallel computers may lead to users being unable or unsure how to achieve optimal performance from their applications and fully utilize their HPC resources. The Performance Optimisation and Productivity Centre of Excellence in Computing Applications (POP) has received funding from the European Commission as part of the Horizon 2020 programme to help alleviate these issues. It aims to uncover inefficiencies and their causes in existing parallel HPC applications that will lead to an improvement in the productivity and competitiveness of European organizations, in academia, government and industry. The POP project will drive efforts to highlight the need for and best practices in performance optimization through performance audits on codes along with training events to improve knowledge in this area. The aim is to help developers target their code development and refactoring in the most efficient direction and provide a return on investment from the savings due to the performance improvement. The POP project combines the expertise and experience of Barcelona Supercomputing Center (BSC), High Performance Computing Center Stuttgart, Jülich Supercomputing Centre (JSC), Numerical Algorithms Group Ltd (NAG), RWTH Aachen and TERATEC. This combination provides longstanding and well respected resources in the academic and commercial realms. The POP members have come together to create a coherent and consistent methodology to give a clear, precise and useful overview of the performance of each HPC application. The services of the POP project are free of charge to organizations with in the EU to analyze and advise on any parallel code in academic, government or industrial organizations of any domain.Peer ReviewedPostprint (author's final draft

It’s All About Context: Investigating the Effects of Consonant and Vowel Environment on Vowel-Evoked Envelope Following Responses

The envelope following response (EFR) has proven useful for studying brainstem speech processing. Previous work, however, demonstrates that its amplitude varies across stimuli. This thesis investigates whether this variation is attributable to the consonant or vowel context of the stimulus, or some interaction of the two. Experiment 1 evoked EFRs in 30 participants using seven English vowels embedded in four CVC environments. A strong effect of vowel and a minor effect of consonant on EFR amplitude were found. In Experiment 2, 64 listeners heard four different tokens of one of four possible English vowels (16 participants/vowel), embedded in the same CVC environments as before. A significant three-way interaction between vowel, vowel trial, and consonant was found, indicating that the EFR is highly sensitive to subtle acoustic differences in stimuli. To effectively utilize the EFR in research, future studies should carefully explore the mechanisms driving these complex context effects

Challenges and opportunities in fast pyrolysis of biomass:Part I

Fast pyrolysis for liquids has been developed in recent decades as a fast and flexible method to provide high yields of liquid products. An overview of this promising field is given, with a comprehensive introduction as well as a practical guide to those thinking of applying fast pyrolysis liquids (bio-oil) in various applications. It updates the literature with recent developments that have occurred since the reviews cited herein. Part I contains an introduction to the background, science, feedstocks, technology and products available for fast pyrolysis. Part II will detail some of the promising applications as well as pre-treatment and bio-oil upgrading options. The applications include use of bio-oil as an energy carrier, precursor to second generation biofuels, as part of a biorefinery concept and upgrading to fuels and chemicals

The Steward, the King, and the Queen: Fealty and Love in Tolkien\u27s \u3ci\u3eThe Lord of the Rings\u3c/i\u3e and in \u3ci\u3eSir Orfeo\u3c/i\u3e

Finds connections between The Lord of the Rings and Tolkien’s long professional engagement with the medieval romance Sir Orfeo. Orfeo’s plot elements of a king’s separation from his queen and his testing of his steward are echoed (albeit in a somewhat fragmented way) and re–examined in the relationships of Aragorn, Arwen, and the house of the Stewards of Gondor

Regional variation in the Amitsoq gneisses related to crustal levels during late Archean granulite facies metamorphism: Southern west Greenland

The dominant lithology at Kangimut sangmissoq is described as nebulitic tonalitic gneiss containing highly distended plagioclase phyric amphibolites. The gneiss amphibolite complex was intruded by Nuk gneiss between 3.05 and 2.90 Ga and later (2.6 to 2.7 Ga) by post granulite facies granitoid sheets. The amphibolites are though to be Ameralik dikes and the older gray gneiss are then Amitsoq by definition. The problem arises when the isotopic data are considered, none of which indicate rocks older that about 3.0 Ga

Analysis of the fume produced during laser-material interactions

The purpose of this research was to improve knowledge of the by-products of laser processing; namely the composition of particles, gases and vapours that are evolved during laser-material interactions. For IR sources, photothermal processes occur and thermal degradation products result, whereas UV lasers may additionally induce photochemical effects. The material investigated was an ITO ink (indium tin oxide nanoparticles in a photo-curable binder and organic solvent) spin-coated onto glass substrates. Thermogravimetric analysis showed that even for temperatures below the upper working limit of the glass substrate, gas-phase products are produced. Laser heating of the binder, 3-methacryloxypropyl-trimethoxysilane (MPTS), in a closed chamber showed that infrared irradiation generates butyl methacrylate. In order to collect a sample representative of the fume entrained in a local exhaust ventilation (LEV) system, an isokinetic arrangement was de- veloped. This balances the volumetric flow rates of the main extraction flow and a sampling tube so that both experience the same flow velocity. Gases were collected with this system into a Tedlar bag and then adsorbed onto a solid phase microextraction (SPME) fibre followed by GC-MS analysis. However, contami- nation from polymers in the sampling system was detected and so a glass/metal construction was utilized in the final version. The gas phase data were inconclusive as no peaks above the detection limits of the equipment could be attributed to laser interactions. The cause of this has been tentatively attributed to excessive dilution of the analytes. Through SEM and EDXA measurements, particulates captured following 130mJ/cm2 XeCl laser irradiation were successfully identified as 40nm ITO particle clusters. It is concluded that the use of a three-stage LEV system is advisable with pre-filter, HEPA filter, and activated charcoal. A flow rate of at least 150m3/hr is recommended, and personal monitoring is advised

Characterisation of a nuclear cave environment utilising an autonomous swarm of heterogeneous robots

As nuclear facilities come to the end of their operational lifetime, safe decommissioning becomes a more prevalent issue. In many such facilities there exist ‘nuclear caves’. These caves constitute areas that may have been entered infrequently, or even not at all, since the construction of the facility. Due to this, the topography and nature of the contents of these nuclear caves may be unknown in a number of critical aspects, such as the location of dangerous substances or significant physical blockages to movement around the cave. In order to aid safe decommissioning, autonomous robotic systems capable of characterising nuclear cave environments are desired. The research put forward in this thesis seeks to answer the question: is it possible to utilise a heterogeneous swarm of autonomous robots for the remote characterisation of a nuclear cave environment? This is achieved through examination of the three key components comprising a heterogeneous swarm: sensing, locomotion and control. It will be shown that a heterogeneous swarm is not only capable of performing this task, it is preferable to a homogeneous swarm. This is due to the increased sensory and locomotive capabilities, coupled with more efficient explorational prowess when compared to a homogeneous swarm

Kinetic study of the pyrolysis of miscanthus and its acid hydrolysis residue by thermogravimetric analysis

The kinetic parameters of the pyrolysis of miscanthus and its acid hydrolysis residue (AHR) were determined using thermogravimetric analysis (TGA). The AHR was produced at the University of Limerick by treating miscanthus with 5 wt.% sulphuric acid at 175 °C as representative of a lignocellulosic acid hydrolysis product. For the TGA experiments, 3 to 6 g of sample, milled and sieved to a particle size below 250 μm, were placed in the TGA ceramic crucible. The experiments were carried out under non-isothermal conditions heating the samples from 50 to 900 °C at heating rates of 2.5, 5, 10, 17 and 25 °C/min. The activation energy (EA) of the decomposition process was determined from the TGA data by differential analysis (Friedman) and three isoconversional methods of integral analysis (Kissinger–Akahira–Sunose, Ozawa–Flynn–Wall, Vyazovkin). The activation energy ranged from 129 to 156 kJ/mol for miscanthus and from 200 to 376 kJ/mol for AHR increasing with increasing conversion. The reaction model was selected using the non-linear least squares method and the pre-exponential factor was calculated from the Arrhenius approximation. The results showed that the best fitting reaction model was the third order reaction for both feedstocks. The pre-exponential factor was in the range of 5.6 × 1010 to 3.9 × 10+ 13 min− 1 for miscanthus and 2.1 × 1016 to 7.7 × 1025 min− 1 for AHR