Computational prediction of L_{3} EXAFS spectra of gold nanoparticles from classical molecular dynamics simulations

We present a computational approach for the simulation of extended x-ray absorption fine structure (EXAFS) spectra of nanoparticles directly from molecular dynamics simulations without fitting any of the structural parameters of the nanoparticle to experimental data. The calculation consists of two stages. First, a molecular dynamics simulation of the nanoparticle is performed and then the EXAFS spectrum is computed from “snapshots” of structures extracted from the simulation. A probability distribution function approach calculated directly from the molecular dynamics simulations is used to ensure a balanced sampling of photoabsorbing atoms and their surrounding scattering atoms while keeping the number of EXAFS calculations that need to be performed to a manageable level. The average spectrum from all configurations and photoabsorbing atoms is computed as an Au L3-edge EXAFS spectrum with the FEFF 8.4 package, which includes the self-consistent calculation of atomic potentials. We validate and apply this approach in simulations of EXAFS spectra of gold nanoparticles with sizes between 20 and 60 Å. We investigate the effect of size, structural anisotropy, and thermal motion on the gold nanoparticle EXAFS spectra and we find that our simulations closely reproduce the experimentally determined spectra

Comparison of the spinels Co3O4 and NiCo2O4 as bifunctional oxygen catalysts in alkaline media

Data from experiments with both rotating disc electrodes (RDEs) and gas diffusion electrodes (GDEs) are used to investigate the properties of the spinels, Co3O4 and NiCo2O4, as bifunctional oxygen electrocatalysts. Emphasis is placed on catalyst compositions and electrode structures free of carbon. Oxygen evolution and reduction occur at surfaces where the transition metals are in different oxidation states but the surface can be repeatedly cycled between these two states without significant change. It is shown that carbon-free, NiCo2O4 catalysed GDEs can be fabricated using structures based on stainless steel cloth or nickel foam. Those based on nickel foam can be cycled extensively and allow both O2 evolution and reduction at current densities up to 100 mA cm?2

A novel bifunctional oxygen GDE for alkaline secondary batteries

AbstractThis paper describes a novel procedure for the fabrication of a gas diffusion electrode (GDE) suitable for use as a bifunctional oxygen electrode in alkaline secondary batteries. The electrode is fabricated by pre-forming a PTFE-bonded nickel powder layer on a nickel foam substrate followed by deposition of NiCo2O4 spinel electrocatalyst by dip coating in a nitrate solution and thermal decomposition. The carbon-free composition avoids concerns over carbon corrosion at the potentials for oxygen evolution. The electrode shows acceptable overpotentials for both oxygen evolution and oxygen reduction at current densities up to 100mAcm−2. Stable performance during >100 successive, 1h oxygen reduction/evolution cycles at a current density of 20mAcm−2 in 8M NaOH at 333K was achieved

A novel bifunctional oxygen GDE for alkaline secondary batteries

This paper describes a novel procedure for the fabrication of a gas diffusion electrode (GDE) suitable for use as a bifunctional oxygen electrode in alkaline secondary batteries. The electrode is fabricated by pre-forming a PTFE-bonded nickel powder layer on a nickel foam substrate followed by deposition of NiCo2O4 spinel electrocatalyst by dip coating in a nitrate solution and thermal decomposition. The carbon-free composition avoids concerns over carbon corrosion at the potentials for oxygen evolution. The electrode shows acceptable overpotentials for both oxygen evolution and oxygen reduction at current densities up to 100 mA cm−2. Stable performance during >100 successive, 1 h oxygen reduction/evolution cycles at a current density of 20 mA cm−2 in 8 M NaOH at 333 K was achieved.European Commissio

Turvatuotteiden käyttö Oulun yliopistollisen sairaalan anestesia- ja teho-osastoilla

Väisänen, Anu. Turvatuotteiden käyttö Oulun yliopistollisen sairaalan anestesia- ja teho-osastoilla. Syksy 2016. 24 sivua, 2 liitettä. Diakonia-ammattikorkeakoulu, Hoitotyön koulutusohjelma, Hoitotyön suuntautumisvaihtoehto, Sairaanhoitaja (AMK). Opinnäytetyön tarkoituksena oli kuvata Oulun yliopistollisen sairaalan operatiivisen tulosyksikön henkilökunnan kokemuksia turvatuotteiden käytöstä sekä pisto- ja viiltotapaturmista. Opinnäytetyö toteutettiin kyselytutkimuksena. Aineisto käsiteltiin määrällisin menetelmin. Opinnäytetyö tehtiin yhteistyössä Oulun yliopistollisen sairaalan operatiivisen tulosalueen kanssa. Tulosten mukaan käyttökokemukset olivat melko hyviä. Moni valitsi turvatuotteen tapaturmalta suojautuakseen. Opinnäytetyön tavoitteena on kehittää hoitotyön turvallisuutta. Jatkossa kannattaa kartoittaa kokemuksia erilaisten turvatuotteiden käytöstä.Väisänen, Anu. Safety products in Oulu University Hospital's anaesthesia and intensive care units. Language: Finnish. Autumn 2016, 24 pages, 2 appendices. Diaconia University of Applied Sciences. Degree Programme in Nursing, Option in Nursing. Degree: Registered Nurse. The purpose of the present thesis was to describe personnel’s experiences of sharp-object injuries and using safety equipment in the operative unit of Oulu University Hospital, Finland. The thesis was conducted as a questionnaire survey. The answers were processed through quantitative methods. This thesis was made in co-operation with the operative unit of Oulu University Hospital. According to the survey, experiences in using safety products were rather positive. The main reason for selecting a safety product was to protect oneself against sharp injuries. The aim of the thesis was to develop nursing safety. In the future it could be good to map out experiences in using various security products

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo

Exploring the first steps in core–shell electrocatalyst preparation: in situ characterization of the underpotential deposition of Cu on supported Au nanoparticles

The underpotential deposition (upd) of a Cu shell on a non-Pt nanoparticle core followed by galvanic displacement of the Cu template shell to form core-shell electrocatalyst materials is one means by which the Pt-based mass activity targets required for commercialization of PEM fuel cells may be reached. In situ EXAFS measurements were conducted at both the Au L(3) and the Cu K absorption edges during deposition of Cu onto a carbon-supported Au electrocatalyst to study the initial stages of formation of such a core shell electrocatalyst. The Au L(3) EXAFS data obtained in 0.5 mol dm(-3) H(2)SO(4) show that the shape of the Au core is potential dependent, from a flattened to a round spherical shape as the Cu upd potential is approached. Following the addition of 2 mmol dm(-3) Cu, the structure was also measured as a function of the applied potential. At +0.2 V vs Hg/Hg(2)SO(4), the Cu(2+) species was found to be a hydrated octahedron. As the potential was made more negative, single-crystal studies predict an ordered bilayer of sulfate anions and partially discharged Cu ions, followed by a complete/uniform layer of Cu atoms. In contrast, the model obtained by fitting the Au L(3) and Cu K EXAFS data corresponds first to partially discharged Cu ions deposited at the defect sites in the outer shell of the Au nanoparticles at -0.42 V, followed by the growth of dusters of Cu atoms at -0.51 V. The absence of a uniform/complete Cu shell, even at the most negative potentials investigated, has implications for the structure, and the activity and/or stability, of the core-shell catalyst that would be subsequently formed following galvanic displacement of the Cu shell

A multi-scale study of 3D printed Co-Al2O3 catalyst monoliths versus spheres

This study demonstrates the characteristics of two model packing configurations: 3D printed (3DP) catalyst monoliths on the one hand, and their conventional counterparts, packed beds of spheres, on the other. Cobalt deposited on alumina is selected as a convenient model system for this work, due to its wide spread use in many catalytic reactions. 3DP constructs were produced from alumina powder impregnated with cobalt nitrate while the alumina spheres were directly impregnated with the same cobalt nitrate precursor. The form of the catalyst, the impregnation process, as well as the thermal history, were found to have a significant effect on the resulting cobalt phases. Probing the catalyst bodies in situ by XRD-CT indicated that the level of dispersion of identified Co phases (Co3O4 reduced to CoO) across the support is maintained under reduction conditions. The packed bed of spheres exhibits a non-uniform distribution of cobalt phases, including a core-shell morphology with an average crystallite size of 10–14 nm across the sphere, while the 3DP monolith exhibits a uniform distribution of cobalt phases with an average crystallite size of 5–12 nm upon reduction from Co3O4 to CoO. Computational Fluid Dynamics (CFD) modelling was carried out to develop digital twins and assess the effect of the geometry of both configurations on the pressure drop and velocity profiles. Finally, the activity of both Cobalt-based catalyst geometries was assessed in terms of their conversion, selectivity and turn over frequencies under model multiphase (selective oxidation) reaction conditions, which showed that the desired 3D printed monolithic geometries can offer distinct advantages to the reactor design