Geochemistry of post-tectonic mafic intrusions in the Central Gneiss Terrane of southwestern Newfoundland

South of Grand Lake, mafic igneous complexes of proven or probable Silurian age intruded quartzofeldspathic gneisses that had been deformed and raised to granulite fades in mid-Ordovician time. The mafic igneous complexes consist of gabbroic units, which locally exhibit igneous layering and contain ultramafic cumulate pods, that grade to and are cut by finer-grained hornblende gabbro. Compositions more felsic than diorite exhibit intrusive to co-mingling relationships with more mafic rocks. Chemical data for possible liquid-derived rocks exhibit characteristics suggesting derivation from diverse mantle sources, followed by varying combinations of fractionation, contamination, mixing and metasomatism by hydrous fluids during ascent and emplacement. The post-tectonic emplacement of the plutons suggests stabilisation of die Central Gneiss Terrane by late Ordovician or Silurian time, when the adjacent terrane to the southeast (Meelpaeg Terrane) was still undergoing deformation and granitic plutonism. RÉSUMÉ Au sud de Grand Lake, des complexes ignés mafiques, dont l’âge est assurément ou probablement silurien, firent intrusion dans desgneiss quartzofeldspathiques qui avaient été déforrnés avaient atteint le faciès des granulites au milieude l’Ordovicien. Les complexes ignés mafiques sont constitues d'unités gabbroiques (montrant localement un aspect rubanné et contenant des lentilles de cumulate ultramaflques) passant graduellement à un gabbro à hornblende moins grenu qui les recoupe aussi. Les compositions plus felsiques que la diorite sont en relation d'intrusion ou de mélange avec les roches plus mafiques. Les données chimiques concernant des roches possiblement derives du liquide montrent des caractéres suggèrant une dérivation à partir de diverses sources mantelliques, suivie d'une combinaison variée de fractionnement, contamination, mélange et métasomatisme par des fluides aqueux durant l'ascension et l’emplacement. L'emplacement post-tectonique des plutons suggère une stabilisation de la lanière Central Gneiss Terrane avant l'Ordovicien tardif ou le Silurien, au moment ou la lanière adjacente au sud-est (la Lanière de Meelpaeg) subissait encore une déformation et un plutonisme granitique. [Traduit par le journal

Optimal energy management for a flywheel-based hybrid vehicle

This paper presents the modeling and design of an optimal Energy Management Strategy (EMS) for a flywheel-based hybrid vehicle, that does not use any electrical motor/generator, or a battery, for its hybrid functionalities. The hybrid drive train consists of only low-cost components, such as a flywheel module and a continuously variable transmission. This hybrid drive train is characterized by a relatively small energy capacity (flywheel) and discrete shifts between operation modes, due to the use of clutches. The main design criterion of the optimized EMS is the minimization of the overall fuel consumption, over a pre-defined driving cycle. In addition, comfort criteria are formulated as constraints, e.g., to avoid high-frequent shifting between driving modes. The criteria are used to find the optimal sequence of driving modes and the generated engine torque. Simulations show a fuel saving potential of 20% to 39%, dependent on the chosen driving cycle

Age of high-grade gneisses south of Grand Lake, Newfoundland

Crystalline rocks of the Steel Mountain Subzone of the Humber Zone in southwest Newfoundland give an age for granulite-grade metamorphism of 1498+9/-8 Ma, similar to ages from the Long Range inlier and northwestern Cape Breton Island. Peralkaline leucogranite was emplaced at 608 ± 4 Ma. The emplacement of anorthosite-gabbro complexes and amphibolite-grade metamorphism took place between these dates. The southern part of the Dunnage Zone (Central Gneiss Subzone), in contact with the Steel Mountain Subzone at the Long Range Fault, lacks Precambrian crystalline rocks, but was intruded by charnockitic plutons and metamorphosed to granulite facies at 460 ±10 Ma. This subzone was exhumed before 435 Ma. In the Meelpaeg Subzone of the Gander Zone, which is in contact with the Central Gneiss Subzone along the Victoria River Fault, the oldest intrusive component of a granoblastic migmatitic gneiss was emplaced at 418 ± 4 Ma. These data demonstrate that both the Long Range and Victoria River faults form major tectonic boundaries. Subzones appear to have been thrust westward in Silurian or later time. RÉSUMÉ Les roches cristallines de la sous-zone du mont Steel, dans la zone de Humber du sud-ouest de Terre-Neuve, ont donné des âges de 1498+9/-8 Ma pour le métamorphisme de haul grade, similaires à ceux de la boutonnière de Long Range et du nord de l'ile-du-Cap-Breton. Un leucogranite peralcalin s'est mis en place à 608 ± 4 Ma. L'intrusion des complexes à anorthosite-gabbro et le métamorphisme au faciès amphibolite se sont produits entre ces deux évènements. La partie sud de la zone de Dunnage (sous-zone de gneiss centrale), en contact avec la sous-zone du mont Steel a la faille de Long Range, ne contient pas de roches cristallines précambriennes mais à 616 recouped par des plutons charnockitiques et à 616 métamorphisée au faciès granulite à 460 ± 10 Ma. Cette sous-zone a été exhumge avant 435 Ma. Dans la sous-zone Mulpaeg de la zone de Gander, qui est mise en contact avec la sous-zone de gneiss centrale par la faille de la rivière Victoria, la phase intrusive la plus ancienne d'un gneiss migmatitique et granoblastique s'est mise en place à 418 ± 4 Ma. Ces données démontrent que les failles de Long Range et de la rivière Victoria sont des frontières tectoniques majeures. Les sous-zones semblent avoir subi un chevauchement vers l'ouest au plus tard au Silurien. [Traduit par le journal

Understanding the Impact of Different Types of Surface States on Photoelectrochemical Water Oxidation: A Microkinetic Modeling Approach

The oxygen evolution reaction (OER) has been identified as one of the performance-limiting processes in solar water splitting using photoelectrochemical (PEC) cells. One of the reasons for the low OER performance is related to the existence of different types of surface states at the semiconductor–electrolyte interface: recombining surface states (r-SS) and surface states due to intermediate species (i-SS). Since the impact of surface states on OER is still under debate, we investigate how different types of surface states affect PEC water oxidation and how they impact experimental measurements. In a new computational approach, we combine a microkinetic model of the OER on the semiconductor surface with the charge carrier dynamics within the semiconductor. The impact of r-SS and i-SS on the current–voltage curves, hole flux, surface state capacitance, Mott–Schottky plots, and chopped light measurements is systematically investigated. It is found that (a) r-SS results in a capacitance peak below the OER onset potential, while i-SS results in a capacitance peak around the onset potential; (b) r-SS leads to an increase in the OER onset potential and a decrease in the saturation current density; (c) r-SS leads to Fermi-level pinning before the onset potential, while i-SS does not result in Fermi-level pinning; and (d) a smaller capacitance peak of i-SS can be an indication of the lower catalytic performance of the semiconductor surface. Our approach in combination with experimental comparison allows distinguishing the impact of r-SS and i-SS in PEC experiments. We conclude that r-SS reduces the OER performance and i-SS mediates the OER.</p

FUTURES-AMR: Towards an Adaptive Mesh Refinement Framework for Geosimulations

Adaptive Mesh Refinement (AMR) is a computational technique used to reduce the amount of computation and memory required in scientific simulations. Geosimulations are scientific simulations using geographic data, routinely used to predict outcomes of urbanization in urban studies. However, the lack of support for AMR techniques with geosimulations limits exploring prediction outcomes at multiple resolutions. In this paper, we propose an adaptive mesh refinement framework FUTURES-AMR, based on static user-defined policies to enable multi-resolution geosimulations. We develop a prototype for the cellular automaton based urban growth simulation FUTURES by exploiting static and dynamic mesh refinement techniques in conjunction with the Patch Growing Algorithm (PGA). While, the static refinement technique supports a statically defined fixed resolution mesh simulation at a location, the dynamic refinement technique supports dynamically refining the resolution based on simulation outcomes at runtime. Further, we develop two approaches - asynchronous AMR and synchronous AMR, suitable for parallel execution in a distributed computing environment with varying support for solution integration of the multi-resolution results. Finally, using the FUTURES-AMR framework with different policies in an urban study, we demonstrate reduced execution time, and low memory overhead for a multi-resolution simulation