Preparation of hard carbon carbon nitride nanocomposites by chemical vapor deposition to reveal the impact of open and closed porosity on sodium storage

The sodium ion battery is a promising successor for the lithium ion battery. Its energy density is limited by the anode, where sodium ideally is stored at low potentials vs. Na Na . The understanding of the fundamental relationships between material properties and sodium storage is often lagging behind materials development. There is a discord regarding the involvement of so called closed pores in carbons in sodium storage. To investigate their influence, a chemical vapor deposition CVD process to deposit polymeric carbon nitride p C3N4 on hard carbon fibres of both, open and closed microporosity, is developed. High storage capacity at a low potential is only possible, when suitable, sealed pores are present. In fibers without notable gas accessible surface, p C3N4 is deposited on the external area, whereas in open microporous samples the p C3N4 phase grows in micropores. Consequently, except for the untreated fibres with closed pores, the composite with a pore gradient along the fibers is the only one in the study that is able to accommodate sodium at low potentials. Neither the remaining graphitic domains, nor the introduced p C3N4 are able to accommodate sodium in a quasimetallic state. Finally, not only the sodium storage but also the solid electrolyte interphase SEI build up is influenced by the additional p C3N4 laye

Mechanistic insights into the reversible lithium storage in an open porous carbon via metal cluster formation in all solid-state batteries

Porous carbons are promising anode materials for next generation lithium batteries due to their large lithium storage capacities. However, their high voltage slope during lithiation and delithiation as well as capacity fading due to intense formation of solid electrolyte interphase (SEI) limit their gravimetric and volumetric energy densities. Herein we compare a microporous carbide-derived carbon material (MPC) as promising future anode for all solid-state batteries with a commercial high-performance hard carbon anode. The MPC obtains high and reversible lithiation capacities of 1000 mAh g−1carbon in half-cells exhibiting an extended plateau region near 0 V vs. Li/Li+ preferable for full-cell application. The well-defined micro porosity of the MPC with a specific surface area of >1500 m2 g−1 combines well with the argyrodite-type electrolyte (Li6PS5Cl) suppressing extensive SEI formation to deliver high coulombic efficiencies. Preliminary full-cell measurements vs. nickel-rich NMC-cathodes (LiNi0.9Co0.05Mn0.05O2) provide a considerably improved average potential of 3.76 V leading to a projected energy density as high as 449 Wh kg−1 and reversible cycling for more than 60 cycles. 7Li Nuclear Magnetic Resonance spectroscopy was combined with ex-situ Small Angle X-ray Scattering to elucidate the storage mechanism of lithium inside the carbon matrix. The formation of extended quasi-metallic lithium clusters after electrochemical lithiation was revealed

Farmland biodiversity and agricultural management on 237 farms in 13 European and two African regions

Farmland is a major land cover type in Europe and Africa and provides habitat for numerous species. The severe decline in farmland biodiversity of the last decades has been attributed to changes in farming practices, and organic and low-input farming are assumed to mitigate detrimental effects of agricultural intensification on biodiversity. Since the farm enterprise is the primary unit of agricultural decision making, management-related effects at the field scale need to be assessed at the farm level. Therefore, in this study, data were collected on habitat characteristics, vascular plant, earthworm, spider, and bee communities and on the corresponding agricultural management in 237 farms in 13 European and two African regions. In 15 environmental and agricultural homogeneous regions, 6–20 farms with the same farm type (e.g., arable crops, grassland, or specific permanent crops) were selected. If available, an equal number of organic and non-organic farms were randomly selected. Alternatively, farms were sampled along a gradient of management intensity. For all selected farms, the entire farmed area was mapped, which resulted in total in the mapping of 11 338 units attributed to 194 standardized habitat types, provided together with additional descriptors. On each farm, one site per available habitat type was randomly selected for species diversity investigations. Species were sampled on 2115 sites and identified to the species level by expert taxonomists. Species lists and abundance estimates are provided for each site and sampling date (one date for plants and earthworms, three dates for spiders and bees). In addition, farmers provided information about their management practices in face-to-face interviews following a standardized questionnaire. Farm management indicators for each farm are available (e.g., nitrogen input, pesticide applications, or energy input). Analyses revealed a positive effect of unproductive areas and a negative effect of intensive management on biodiversity. Communities of the four taxonomic groups strongly differed in their response to habitat characteristics, agricultural management, and regional circumstances. The data has potential for further insights into interactions of farmland biodiversity and agricultural management at site, farm, and regional scale

Direct observation of ion dynamics in supercapacitor electrodes using in situ diffusion NMR spectroscopy

Ionic transport inside porous carbon electrodes underpins the storage of energy in supercapacitors and the rate at which they can charge and discharge, yet few studies have elucidated the materials properties that influence ion dynamics. Here we use in situ pulsed field gradient NMR spectroscopy to measure ionic diffusion in supercapacitors directly. We find that confinement in the nanoporous electrode structures decreases the effective self-diffusion coefficients of ions by over two orders of magnitude compared with neat electrolyte, and in-pore diffusion is modulated by changes in ion populations at the electrode/electrolyte interface during charging. Electrolyte concentration and carbon pore size distributions also affect in-pore diffusion and the movement of ions in and out of the nanopores. In light of our findings we propose that controlling the charging mechanism may allow the tuning of the energy and power performances of supercapacitors for a range of different applications

Diabetic ketoacidosis

Diabetic ketoacidosis (DKA) is the most common acute hyperglycaemic emergency in people with diabetes mellitus. A diagnosis of DKA is confirmed when all of the three criteria are present — ‘D’, either elevated blood glucose levels or a family history of diabetes mellitus; ‘K’, the presence of high urinary or blood ketoacids; and ‘A’, a high anion gap metabolic acidosis. Early diagnosis and management are paramount to improve patient outcomes. The mainstays of treatment include restoration of circulating volume, insulin therapy, electrolyte replacement and treatment of any underlying precipitating event. Without optimal treatment, DKA remains a condition with appreciable, although largely preventable, morbidity and mortality. In this Primer, we discuss the epidemiology, pathogenesis, risk factors and diagnosis of DKA and provide practical recommendations for the management of DKA in adults and children

HISGIS: Golvenmodel HISWA onder GIS pakket ARC/INFO

HISWA is een tweedimensionaal golvenmodel, dat de gebruiker in staat stelt diverse golfgegevens, zoals significante golfhoogte, periode en golfrichting, voor een bepaald modelgebied te bepalen. Op dit moment biedt HISWA al faciliteiten om pre- en postprocessing uit te voeren (zij het in beperkte mate). Onder de gebruikers echter is er behoefte aan meer en uitgebreidere mogelijkheden. Door de functionaliteiten op het gebied van weergave en analyse van gegevens, leent een GIS (Geografisch Informatie Systeem) zich uitstekend voor pre- en post-processing doeleinden. Het doel van het project is het koppelen van HISWA aan een GIS-pakket, en wel op een dusdanige manier dat een gebruikersvriendelijke schil ontstaat, waarbinnen een HISWA berekening kan worden uitgevoerd en tevens van de functionaliteiten van het GIS-pakket gebruik kan worden gemaakt voor pre- en post-processing doeleinden. Aan de hand van de resultaten van een vragenformulier zijn de eisen en wensen van de huidige HISWA-gebruiker, met betrekking tot bovengenoemde koppeling, geïnventariseerd. Tevens zijn uit deze resultaten conclusies getrokken wat betreft de benodigde functionaliteiten van het te gebruiken GIS-pakket. Er is, voorafgaand aan het afstudeerproject, gekozen voor 's werelds meest gebruikte en veruit bekendste GIS-pakket, ARC/INFO. Uit onderzoek, uitgevoerd tijdens het afstudeerproject, blijkt, dat het pakket over vrijwel alle benodigde functionaliteiten beschikt. In ARC/INFO's macrotaai AML (ARC/INFO Macro Language) is een volledig menugestuurde applicatie ontwikkeld, genaamd HISGIS. De applicatie HISGIS bestaat uit een viertal delen, te weten het hoofdprogramma, een 'Pre-processing module', een 'Calculation module' en een 'Post-processing module'. In het hoofdprogramma kunnen de drie modules met behulp van een menu worden aangeroepen.Hydraulic EngineeringCivil Engineering and Geoscience