921 research outputs found

    Direct electrodeposition of aluminium nano-rods

    Get PDF
    Electrodeposition of aluminium within an alumina nano-structured template, for use as high surface area current collectors in Li-ion microbatteries, was investigated. The aluminium electrodeposition was carried out in the ionic liquid 1-ethyl-3-methylimidazolium chloride:aluminium chloride (1:2 ratio). First the aluminium electrodeposition process was confirmed by combined cyclic voltammetry and electrochemical quartz crystal microbalance measurements. Then, aluminium was electrodeposited under pulsed-potential conditions within ordered alumina membranes. A careful removal of the alumina template unveiled free standing arrays of aluminium nano-rods. The nano-columns shape and dimensions are directly related to the template dimensions. To our knowledge, this is the first time that direct electrodeposition of aluminium nano-pillars onto an aluminium substrate is reported

    Generative Design in Minecraft (GDMC), Settlement Generation Competition

    Full text link
    This paper introduces the settlement generation competition for Minecraft, the first part of the Generative Design in Minecraft challenge. The settlement generation competition is about creating Artificial Intelligence (AI) agents that can produce functional, aesthetically appealing and believable settlements adapted to a given Minecraft map - ideally at a level that can compete with human created designs. The aim of the competition is to advance procedural content generation for games, especially in overcoming the challenges of adaptive and holistic PCG. The paper introduces the technical details of the challenge, but mostly focuses on what challenges this competition provides and why they are scientifically relevant.Comment: 10 pages, 5 figures, Part of the Foundations of Digital Games 2018 proceedings, as part of the workshop on Procedural Content Generatio

    A self-grounded dual-polarized wideband bowtie with improved MIMO performance in Random-LOS

    Get PDF
    We present a new improved design of the self-grounded dual-polarized wideband bowtie antenna for MIMO application. The antenna is evaluated for the case when the original four ports are combined to two orthogonally polarized ports. The new antenna covers the previous bandwidth but has lower gain and wider beamwidth over the frequency band of interest. The 2×2 MIMO performance of the antenna in Random-Line of Sight (Random-LOS) is evaluated for two bitstreams using the threshold receiver model and Zero-Forcing receiver. The simulated results show an improvement in terms of MIMO multiplexing coverage over a hemisphere for two bitstreams, compared to the previous solution

    Electrodeposited Cu2Sb as anode material for 3-dimensional Li-ion microbatteries

    Get PDF
    An increasing demand on high energy and power systems has arisen not only with the development of electric vehicle (EV), hybrid electric vehicle (HEV), telecom, and mobile technologies, but also for specific applications such as powering of microelectronic systems. To power those microdevices, an extra variable is added to the equation: a limited footprint area. Three-dimensional (3D) microbatteries are a solution to combine high-density energy and power. In this work, we present the formation of Cu2Sb onto three-dimensionally architectured arrays of Cu current collectors. Sb electrodeposition conditions and annealing post treatment are discussed in light of their influence on the morphology and battery performances. An increase of cycling stability was observed when Sb was fully alloyed with the Cu current collector. A subsequent separator layer was added to the 3D electrode when optimized. Equivalent capacity values are measured for at least 20 cycles. Work is currently devoted to the identification of the causes of capacity fading

    Skyrmions from a Born-Infeld Action

    Get PDF
    We consider a geometrically motivated Skyrme model based on a general covariant kinetic term proposed originally by Born and Infeld. We introduce this new term by generalizing the Born-Infeld action to a non-abelian SU(2)SU(2) gauge theory and by using the hidden gauge symmetry formalism. The static properties of the Skyrmion are then analyzed and compared with other Skyrme-like models.Comment: 11 pages, 4 figures (not included), revtex v3, LAVAL-PHY-11-9

    Environmental policies to cope with novel disturbance regimes–steps to address a world scientists’ warning to humanity

    Get PDF
    ABL acknowledges postdoctoral funding from the Alexander von Humboldt Foundation and grants RTI2018-096187-J-100 from FEDER/ Ministerio de Ciencia, Innovacion y Universidades and LRB20/1002 from the British Ecological Society.Alexander von Humboldt Foundation RTI2018-096187-J-100FEDER/ Ministerio de Ciencia, Innovacion y Universidades LRB20/1002British Ecological Societ

    Carbon Abundances of Three Carbon-Enhanced Metal-Poor Stars from High-Resolution Gemini-S/bHROS Spectra of the 8727A [C I] Line

    Full text link
    We present the results from an analysis of the 8727ang forbidden [C I] line in high-resolution Gemini-S/bHROS spectra of three CEMP stars. We find the [C/Fe] ratios based on the [C I] abundances of the two most Fe-rich stars in our sample (HIP 0507-1653: [Fe/H] = -1.42 and HIP 0054-2542: [Fe/H] = -2.66) to be in good agreement with previously determined CH and C_2 line-based values. For the most Fe-deficient star in our sample (HIP 1005-1439: [Fe/H] = -3.08), however, the [C/Fe] ratio is found to be 0.34 dex lower than the published molecular-based value. We have carried out 3D local thermodynamic equilibrium (LTE) calculations for [C I], and the resulting corrections are found to be modest for all three stars, suggesting that the discrepancy between the [C I] and molecular-based C abundances of HIP 1005-1439 is due to more severe 3D effects on the molecular lines. Carbon abundances are also derived from C I high-excitation lines and are found to be 0.45-0.64 dex higher than the [C I]-based abundances. Previously published non-LTE C I abundance corrections bring the [C I] and C I abundances into better agreement; however, targeted NLTE calculations for CEMP stars are clearly needed. We have also derived the abundances of N, K, and Fe for each star. The Fe abundances agree well with previously derived values, and the K abundances are similar to those of C-normal metal-poor stars. Nitrogen abundances have been derived from resolved lines of the CN red system. The abundances are found to be approximately 0.44 dex larger than literature values, which have been derived from CN blue bands near 3880 and 4215 ang. We discuss evidence that suggests that analyses of the CN blue system bands underestimate the N abundances of metal-poor giants.Comment: Accepted for publication in AJ; 42 pages, 6 figures, 7 table

    Multi-Element Abundance Measurements from Medium-Resolution Spectra. II. Catalog of Stars in Milky Way Dwarf Satellite Galaxies

    Get PDF
    We present a catalog of Fe, Mg, Si, Ca, and Ti abundances for 2961 red giant stars that are likely members of eight dwarf satellite galaxies of the Milky Way (MW): Sculptor, Fornax, Leo I, Sextans, Leo II, Canes Venatici I, Ursa Minor, and Draco. For the purposes of validating our measurements, we also observed 445 red giants in MW globular clusters and 21 field red giants in the MW halo. The measurements are based on Keck/DEIMOS medium-resolution spectroscopy combined with spectral synthesis. We estimate uncertainties in [Fe/H] by quantifying the dispersion of [Fe/H] measurements in a sample of stars in monometallic globular clusters. We estimate uncertainties in Mg, Si, Ca, and Ti abundances by comparing our medium-resolution spectroscopic measurements to high-resolution spectroscopic abundances of the same stars. For this purpose, our DEIMOS sample included 132 red giants with published high-resolution spectroscopy in globular clusters, the MW halo field, and dwarf galaxies. The standard deviations of the differences in [Fe/H] and [alpha/Fe] (the average of [Mg/Fe], [Si/Fe], [Ca/Fe], and [Ti/Fe]) between the two samples is 0.15 and 0.16, respectively. This catalog represents the largest sample of multi-element abundances in dwarf galaxies to date. The next papers in this series draw conclusions on the chemical evolution, gas dynamics, and star formation histories from the catalog presented here. The wide range of dwarf galaxy luminosity reveals the dependence of dwarf galaxy chemical evolution on galaxy stellar mass.Comment: 26 pages, 22 figures, 4 machine-readable tables (available in the source file; click "Other formats"); accepted for publication in ApJ Supplements; updated acknowledgments in v

    Cystatin C and alpha-1-Microglobulin Predict Severe Acute Kidney Injury in Patients with Hemorrhagic Fever with Renal Syndrome

    Get PDF
    Puumala orthohantavirus causes hemorrhagic fever with renal syndrome (HFRS) characterized by acute kidney injury (AKI), an abrupt decrease in renal function. Creatinine is routinely used to detect and quantify AKI; however, early AKI may not be reflected in increased creatinine levels. Therefore, kidney injury markers that can predict AKI are needed. The potential of the kidney injury markers urea, cystatin C, α1-microglobulin (A1M) and neutrophil gelatinase-associated lipocalin (NGAL) to detect early AKI during HFRS was studied by quantifying the levels of these markers in consecutively obtained plasma (P) and urine samples (U) for 44 HFRS patients. P-cystatin C and U-A1M levels were significantly increased during early HFRS compared to follow-up. In a receiver operating characteristic (ROC) curve analysis, P-cystatin C, U-A1M and P-urea predicted severe AKI with area under the curve 0.72, 0.73 and 0.71, respectively, whereas the traditional kidney injury biomarkers creatinine and U-albumin did not predict AKI. Nearly half of the HFRS patients (41%) fulfilled the criteria for shrunken pore syndrome, which was associated with the level of inflammation as measured by P-CRP. P-cystatin C and U-A1M are more sensitive and earlier markers compared to creatinine in predicting kidney injury during HFRS

    Uppvärmning av Almunge brandstation med pyrolys

    Get PDF
    This project has been carried out on the behalf of Ihus in collaboration with Stuns Energi. The goal was to find and model a solution based on the process of pyrolysis that can deliver enough heat to Almunge fire station while storing maximum amount of CO2 in the form of biochar. Two systems that primarily used waste heat from a pyrolysis reactor were studied. In one case a wood pellet boiler was used to cover peak load and the second system used a coal boiler that uses some of the coal produced in the reactor. The result shows that both solutions can theoretically deliver the required amount of heat and have lower emissions of carbon dioxide than the current method of heat generation used on the property, a wood pellet boiler. A model of the system that uses a coal boiler shows that it, under a period of one year, releases 5 % more CO2, has a 60 % higher amount of unused waste heat, and consumes 22 % more substrate per month than the system that uses a wood pellet burner. However, the coal boiler resulted in 18 % higher in biochar production, potentially 33 % more coal bound if the produced biochar is used as a carbon sink, and 18 % higher economical value after 20 years.Detta projekt har genomf¨orts p˚a best¨allning av Ihus i samarbete med Stuns Energi. Det gick ut p˚a att hitta och modellera en energil¨osning, baserad p˚a en pyrolysprocess, som f¨orser en brandstation i Almunge med den v¨arme stationen kr¨aver p˚a m˚anadsbasis samtidigt som maximal m¨angd CO2 binds i form av biokol. Tv˚a system som prim¨art anv¨ander spillv¨arme fr˚an en pyrolysreaktor i uppv¨armningssyftet togs fram. I ena fallet anv¨ands en pelletspanna f¨or att t¨acka de effekttopparna som kan uppst˚a och det andra systemet anv¨ander sig av en kolpanna som matas med kolet fr˚an pyrolysprocessen. Resultatet visar att b˚ada l¨osningar kan teoretiskt leverera den m¨angden v¨arme fastigheten kr¨aver och har l¨agre utsl¨app av koldioxid ¨ an den nuvarande d¨ar fastigheten endast v¨arms upp av en pelletspanna. Systemet som anv¨ander sig av kolpannan visade sig under ett ˚ars period sl¨appa ut 5 % mer CO2, har 60 % st¨orre andel av ej utnyttjad spillv¨arme och konsumerar 22 % mer substrat per m˚anad ¨an systemet med pelletspannan men kompenserade det med 18 % h¨ogre produktion av biokol, potentiellt 33 % st¨orre m¨angd kol som binds om biokolet anv¨ands som kols¨anka och 18 % h¨ogre ekonomiskt v¨arde efter 20 ˚ar
    corecore