T–T–T behaviour of bioactive glasses 1–98 and 13–93

In this work crystallization kinetics of bioactive glasses 1–98 and 13–93 are discussed. Within a certain temperature–time window these glasses can be hot worked into various products without interfering with crystallization. The crystallization was studied isothermally by heating glass plates at different temperatures for different times. Phases in the samples were studied through XRD and SEM analyses. The nucleation-like curves and crystallization characteristics were measured with DTA. The temperature of maximum nucleation was measured for glass 1–98 at 725 °C and for 13–93 at 700 °C. The activation energy of crystallization of both glasses was 280 kJ/mol. The Johnson–Mehl–Avrami exponent and the SEM micrographs of the samples suggested surface crystallization. The primary crystalline phase was wollastonite. The growth rate of the crystallized surface layer was 1 order of magnitude higher in the plates of 1–98 than in 13–93. The results can be utilized to optimize the parameters in hot-working of the glasses.     

Low-temperature atomic layer deposition of Al2O3 thin coatings for corrosion protection of steel: Surface and electrochemical analysis

ToF-SIMS, XPS, voltammetry and EIS investigation of the anti-corrosion properties of thin (10, 50 and 100 nm) alumina coatings grown by atomic layer deposition at 160 °C on steel is reported. Surface analysis shows a thickness-independent Al₂O₃ stoichiometry of the coating and trace contamination by the growth precursors. The buried coating/alloy interface has iron oxide formed in ambient air and/or resulting from the growth of spurious traces in the initial stages of deposition. Electrochemical analysis yields an exponential decay of the coating porosity over four orders of magnitude with increasing thickness, achieved by sealing of the more defective first deposited 10 nm.     

Removal of neutrophil gelatinase‐associated lipocalin by extracorporeal therapies

Neutrophil gelatinase‐associated lipocalin (NGAL) protein is an early biomarker for acute kidney injury (AKI). It is unknown if extracorporeal therapies (EC) have an effect on circulating NGAL levels. This study was designed to describe the kinetics of NGAL molecule in different EC techniques and to evaluate NGAL clearance in different operational conditions. A mock hemofiltration (HF) and hemoperfusion (HP) setup was used. NGAL was added to the blood reservoir and then measured at 30‐minute intervals from arterial, venous, and ultrafiltrate (UF) lines. Removal kinetics and NGAL sieving coefficient were calculated. In our experiments, baseline NGAL concentration averaged 452 μg/L. There was a consistent downward trend throughout the experiment. NGAL concentration in the UF was between 80 and 90 μg/L, though it showed a slight increase in the second hour. The sieving coefficient of NGAL ranged from 0.2 to 0.4 during HF and it appeared to increase with time, suggesting an initial effect of membrane adsorption. HP proved clearly that there was adsorption of NGAL by the membrane and the point of saturation occured at approximately 60 minutes from the start of circulation. Our evaluation demonstrates that NGAL can be adsorbed and ultrafiltrated with polysulfone membranes. This should be taken into consideration when using NGAL as an AKI biomarker in patients undergoing EC circulation.     

Advances in Digital Front-End and Software RF Processing： Part II

In the first editorial of this two-part special issue, we pointed out that one of the biggest trends in wireless broadband, radar, sonar, and broadcasting technology is software RF processing and digital front-end [1]. This     

Analysis of experimental factors in elastic–plastic small specimen mixed-mode I-II fracture mechanical testing

The quality of experimental fracture resistance testing results in mixed-mode I-II loading is more than questionable in several cases. This study describes efforts to gain consistent results with respect to mixed-mode I-II fracture resistance curve determination when working with elastic–plastic materials. The entire mixed-mode I-II field is evaluated, i.e. both numerical and experimental factors are considered the focus being on the asymmetric four-point bend set-up. Several error prone features are presented, and minimization of their effects on quantitative fracture resistance assessment considered. The results indicate that through a careful evaluation of the stages in experimental testing and numerical analysis valid, material characterizing, fracture toughness results can be obtained.     

Stabilization and Pumping of Giant Vortices in Dilute Bose–Einstein Condensates

Recently, it was shown that giant vortices with arbitrarily large quantum numbers can possibly created in dilute Bose–Einstein condensates by cyclically pumping vorticity into the condensate. However, multiply quantized vortices are typically dynamically unstable in harmonically trapped nonrotated condensates, which poses a serious challenge to the vortex pump procedure. In this theoretical study, we investigate how the giant vortices can be stabilized by the application of a Gaussian potential peak along the vortex core. We find that achieving dynamical stability is feasible up to high quantum numbers. To demonstrate the efficiency of the stabilization method, we simulate the adiabatic creation of an unsplit 20-quantum vortex with the vortex pump.     

A framework for local and regional energy system integration between industry and municipalities—Case study UPM-Kymmene Kaukas

The integration of different energy systems, e.g., industrial and municipal, is potentially important for the efficient utilization of energy. It is important that the tools for analysing this type of integration can handle the energy systems on different levels, e.g., regional, site, plant and process levels. In this work, a framework for investigating the cost-efficient integration of large-scale energy systems is presented and tested at the UPM-Kymmene Kaukas pulp and paper plant and in the municipality of Lappeenranta, Finland. In addition to the different levels, the framework also aims to take into account several sub-problems, e.g., fuel logistic, optimal heat exchanger network and overall efficiency versus flexibility. The case in question shows that the presented framework can be used as a systematic tool for analysing the potential of integrating large energy systems and that it is able to handle both the synthesis of flexible heat exchanger networks and analyse the cost-efficiency of changes to the existing systems.     

Influence of thickness and growth temperature on the properties of zirconium oxide films grown by atomic layer deposition on silicon

ZrO₂ films of thicknesses varied in the range of 3–30 nm were atomic layer deposited from ZrI₄ and H₂O–H₂O₂ on p-Si(100) substrates. The effects of film thickness and deposition temperature on the structure and dielectric properties of ZrO₂ were investigated. At 272 and 325 °C, the growth of ZrO₂ started with the formation of the cubic polymorph and continued with the formation of the tetragonal polymorph. The ratio between the lattice parameters increased with the film thickness and growth temperature. The effective permittivity, determined from the accumulation capacitance of Hg/ZrO₂/Si capacitors, increased with the film thickness, reaching 15–17 in 25-nm-thick films. The permittivity decreased with the increasing growth temperature. The hysteresis of the capacitance–voltage curves was the narrowest for the films deposited at 325 °C, and increased towards both lower and higher deposition temperatures.     

Inhomogeneous compression of PEMFC gas diffusion layer: Part I. Experimental

This paper presents a study on the effect of inhomogeneous compression of gas diffusion layer (GDL) caused by the channel/rib structure of flow-field plate. The experimentally evaluated properties are GDL intrusion into the channel, gas permeability, in-plane and through-plane bulk electric conductivities, and contact resistances at interfaces as a function of compressed thickness of GDL. It was found that the GDL is compressed very little under the channel whereas GDL under the rib is compressed to gasket thickness. The compression of GDL reduces gas permeability and contact resistance, and improves bulk conductivity. Hence, the inhomogeneous compression of GDL may lead into significant local variation of mass and charge transport properties in the GDL. These effects have been ignored in most of the published modeling studies. This contribution, part I, covers the experimental setup and measurement results, and a model which takes the inhomogeneous compression of GDL into account is presented in part II.