Abstract  As part of the ongoing key comparison BIPM.QM-K1, a comparison has been performed between the ozone standard of the World Meteorological Organisation maintained by the National Metrology Institute of South Africa (NMISA) and the common reference standard of the key comparison, maintained by the Bureau International des Poids et Mesures (BIPM). The instruments have been compared over a nominal ozone amount-of-substance fraction range of 0 nmol/mol to 500 nmol/mol.

Abstract  As part of the ongoing key comparison BIPM.QM-K1, a comparison has been performed between the ozone standard of the Czech Republic maintained by the Czech Hydrometeorological Institute (CHMI) and the common reference standard of the key comparison, maintained by the Bureau International des Poids et Mesures (BIPM). The instruments have been compared over a nominal ozone amount-of-substance fraction range of 0 nmol/mol to 500 nmol/mol.

Abstract  As part of the ongoing key comparison BIPM.QM-K1, a comparison has been performed between the ozone national standard of France maintained by the Laboratoire National de metrologie et d'Essais (LNE) and the common reference standard of the key comparison, maintained by the Bureau International des Poids et Mesures (BIPM). The instruments have been compared over a nominal ozone amount-of-substance fraction range of 0 nmol/mol to 500 nmol/mol.

Abstract  As part of the ongoing key comparison BIPM.QM-K1, a comparison has been performed between the ozone national standard of Singapore maintained by the National Metrology Centre, A*STAR (NMC, A*STAR) and the common reference standard of the key comparison, maintained by the Bureau International des Poids et Mesures (BIPM). The instruments have been compared over a nominal ozone amount-of-substance fraction range of 0 nmol/mol to 500 nmol/mol.

Abstract  Changes in nominal composition of the perovskite (ABO3) solid solution Ba1-x(Zr,Pr)O3-δ and adjusted firing conditions at very high temperatures were used to induce structural changes involving site redistribution and frozen-in point defects, as revealed by Raman and photoluminescence spectroscopies. Complementary magnetic measurements allowed quantification of the reduced content of Pr. Weak dependence of oxygen stoichiometry with temperature was obtained by coulometric titration at temperatures below 1000 °C, consistent with a somewhat complex partial frozen-in defect chemistry. Electrical conductivity measurements combined with transport number and Seebeck coefficient measurements showed prevailing electronic transport and also indicated trends expected for partial frozen-in conditions. Nominal Ba deficiency and controlled firing at very high temperatures allows adjustment of structure and partial frozen-in defect chemistry, opening the way to engineer relevant properties for high-temperature electrochemical applications.

Abstract  An iron-manganese co-oxide filter film (MeOx) has been proven to be a good catalyst for the chemical catalytic oxidation of ammonium in groundwater. Compared with groundwater, surface water is generally used more widely and has characteristics that make ammonium removal more difficult. In this study, MeOxwas used to remove ammonium from surface water. It indicated that the average ammonium removal efficiency of MeOxwas greater than 90%, even though the water quality changed dramatically and the water temperature was reduced to about 6-8 °C. Then, through inactivating microorganisms, it showed that the removal capability of MeOxincluded both biological (accounted for about 41.05%) and chemical catalytic oxidation and chemical catalytic oxidation (accounted for about 58.95%). The investigation of the characterizations suggested that MeOxwas formed by abiotic ways and the main elements on the surface of MeOxwere distributed homogenously. The analysis of the catalytic oxidation process indicated that ammonia nitrogen may interact with MeOxas both ammonia molecules and ammonium ions and the active species of O₂ were possibly•O and O₂-.

Abstract  A metallic nanoparticle-decorated ceramic anode was prepared by in situ reduction of the perovskite Sr2FeMo0.65Ni0.35O6-δ (SFMNi) in H2 at 850 °C. The reduction converts the pure perovksite phase into mixed phases containing the Ruddlesden-Popper structure Sr3FeMoO7-δ, perovskite Sr(FeMo)O3-δ, and the FeNi3 bimetallic alloy nanoparticle catalyst. The electrochemical performance of the SFMNi ceramic anode is greatly enhanced by the in situ exsolved Fe-Ni alloy nanoparticle catalysts that are homogeneously distributed on the ceramic backbone surface. The maximum power densities of the La0.8Sr0.2Ga0.8Mg0.2O3-δ electrolyte supported a single cell with SFMNi as the anode reached 590, 793, and 960 mW cm(-2) in wet H2 at 750, 800, and 850 °C, respectively. The Sr2FeMo0.65Ni0.35O6-δ anode also shows excellent structural stability and good coking resistance in wet CH4. The prepared SFMNi material is a promising high-performance anode for solid oxide fuel cells.

Abstract  For long-term operation of highly loaded biotrickling filters (BTFs), the prevention of excess biomass accumulation was essential for avoiding BTF failure. In this study, we proposed low-dose ozonation as a biomass control strategy to maintain high removal efficiencies of volatile organic compounds (VOCs) over extended operation of BTFs. To obtain an optimized biomass control strategy, the relative performance of five parallel BTFs receiving different ozone doses was determined, and the affecting mechanism of ozonation on biofilm was elucidated. Experimental results showed that the decline in ozone-free BTF performance began from day 150, which was correlated with excess biomass accumulation, abundant excretion of extracellular polymeric substances (EPS) and a decline in metabolic activity of biofilm over extended operation. Ozone of 5-10 mg m(-3) was effective in preventing excessive growth and uneven distribution of biomass, and eventually maintaining long-term stable operations. Ozone of over 20 mg m(-3) possibly inhibited microorganism growth severely, thereby deteriorating the elimination performance instead. Comparison of the biofilm EPS indicated that the presence of ozone reduce EPS contents to different extents, which was possibly beneficial for mass transfer and metabolic activity. Comparative community analysis showed that ozonation resulted in different microbial communities in the BTFs. Dyella was found to be the most abundant bacterial genera in all BTFs regardless of ozonation, indicating strong resistance to ozonation. Chryseobacterium and Burkholderia members were markedly enriched in the ozone-added biofilm, implying good adaptation to ozone presence. These findings provided an improved understanding of low-dose ozonation in maintaining a stable long-term operation of BTF.

Abstract  A mechanistic study of the hydrogenation reaction of levulinic acid (LA) to 2-methyltetrahydrofuyran (MTHF) was performed using three different solvents under reactive H2 and inert N2 atmospheres. Under the applied reaction conditions, catalytic transfer hydrogenation and hydrogenation with molecular H2 were effective at producing high yields of γ-valerolactone. However, the conversion of this stable intermediate to MTHF required the combination of both hydrogen sources (the solvent and the H2 atmosphere) to achieve good yields. The reaction system with 2-propanol as solvent and Ni-Cu/Al2 O3 as catalyst allowed full conversion of LA and a MTHF yield of 80 % after 20 h reaction time at 250 °C and 40 bar of H2 (at room temperature). The system showed the same catalytic activity at LA feed concentrations of 5 and up to 30 wt%, and also when high acetone concentration at the beginning of the reaction were added, which confirmed the potential industrial applications of this solvent/catalyst system.

Abstract  The degradation of aflatoxins AFB1, AFB2, AFG1 and AFG2 after treatment of their solutions in triple distilled water with ozone was studied and the ability of ozone, even at low concentrations, to degrade aflatoxins was proved. Ozone concentrations of 8.5, 13.5, 20, 25 and 40 ppm were applied at different temperatures on aflatoxin solutions in triple distilled water of 10 ppb and 2 ppb and the complete and rapid elimination of AFB1 and AFG1 was observed while AFB2 and AFG2 remain more or less stable. The kinetic equations for the degradation procedure were calculated by applying ozone on neutral buffer solutions of aflatoxin at 298.15, 308.15, 318.15 and 328.15 K at ozone concentrations of 8.5, 13.5 and 20 ppm and the rate constants, were determined. The degradation of aflatoxins was described by a first order kinetic equation. Finally, the activation energies during degradation of aflatoxins were calculated from the Arrhenius equation. (C) 2015 Elsevier Ltd. All rights reserved.

Abstract  The presence of natural organic matter (NOM) in drinking water treatment presents many challenges. Integrated treatment processes combining oxidation and biofiltration have been demonstrated to be very effective at reducing NOM, specifically biodegradable organics. Laboratory bench-scale experiments were carried out to investigate the effect of oxidation by ozonation or UV/H2O2 on NOM. Specifically the rate of biodegradation was studied by performing bench-scale biodegradation experiments using acclimatized biological activated carbon (BAC). For the source water investigated, oxidation did not preferentially react with the biodegradable or non-biodegradable NOM. In addition, the type or dose of oxidation applied did not affect the observed rate of biodegradation. The rate kinetics for biodegradation were constant for all oxidation conditions investigated. Oxidation prior to biofiltration increased the overall removal of organic matter, but did not affect the rate of biodegradation of NOM.

Abstract  Bench-scale experiments were conducted with municipal wastewater effluent samples to examine the feasibility of combined application of ozone and ultraviolet (UV) radiation for disinfection. Effluent samples displayed rapid initial ozone demand, which promotes ozone transfer but diminishes disinfection efficacy. Ozone doses up to 10 mg/L yielded only trace quantities of residual ozone; despite the fact that initial ozone demand was never exceeded, quantifiable (though variable) inactivation of E. coli was observed, along with modest improvements of UV transmittance. Results from collimated beam experiments demonstrated that compliance with effluent discharge permit limitations could be achieved consistently with a UV254 dose of 12.4 mJ/cm(2) at a pre-ozonation dose of 2 to 3 mg/L. In the absence of pre-ozonation, consistent compliance was observed at a UV dose of 16.5 mJ/cm(2). No evidence of synergism between ozone and UV254 radiation was found in the measured inactivation responses of E. coli. Water Environ. Res., 84, 2017 (2012).

Abstract  Early winter ozone mixing ratios in the Arctic middle stratosphere show an interannual variability of about 10 %. We show that ozone variability in early January is caused by dynamical processes during Arctic polar vortex formation in autumn (September to December). Observational data from satellites and ozone sondes are used in conjunction with simulations of the chemistry and transport model ATLAS to examine the relationship between the meridional and vertical origin of air enclosed in the polar vortex and its ozone amount. For this, we use a set of artificial model tracers to deduce the origin of the air masses in the vortex in January in latitude and altitude in September. High vortex mean ozone mixing ratios are correlated with a high fraction of air from low latitudes enclosed in the vortex and a high fraction of air that experienced small net subsidence (in a Lagrangian sense). As a measure for the strength of the Brewer-Dobson circulation and meridional mixing in autumn, we use the Eliassen-Palm flux through the mid-latitude tropopause averaged from September to November. In the lower stratosphere, this quantity correlates well with the origin of air enclosed in the vortex and reasonably well with the ozone amount in early winter.

Abstract  Little is known about the roles of Rictor/mTORC2 in the leukemogenesis of acute myeloid leukemia. Here, we demonstrated that Rictor is essential for the maintenance of mixed lineage leukemia (MLL)-driven leukemia by preventing leukemia stem cells (LSCs) from exhaustion. Rictor depletion led to a reactive activation of mTORC1 signaling by facilitating the assembly of mTORC1. Hyperactivated mTORC1 signaling in turn drove LSCs into cycling, compromised the quiescence of LSCs and eventually exhausted their capacity to generate leukemia. At the same time, loss of Rictor had led to a reactive activation of FoxO3a in leukemia cells, which acts as negative feedback to restrain greater over-reactivation of mTORC1 activity and paradoxically protects leukemia cells from exhaustion. Simultaneous depletion of Rictor and FoxO3a enabled rapid exhaustion of MLL LSCs and a quick eradication of MLL leukemia. As such, our present findings highlighted a pivotal regulatory axis of Rictor-FoxO3a in maintaining quiescence and the stemness of LSCs.

Abstract  Two novel isomers of BeO4 with the structures OBeOOO and OBe(O3 ) in the electronic triplet state have been prepared as well as the known disuperoxide complex Be(O2 )2 in solid noble-gas matrices. We also report the synthesis of the oxygen-rich bis(ozonide) complex Be(O3 )2 in the triplet state which has a D2d equilibrium geometry. The molecular structures were identified by infrared absorption spectroscopy with isotopic substitutions as well as quantum chemical calculations.

Abstract  Sugarcane bagasse (SCB) was ozone pretreated and detoxified by water washing, applying a L9(3)(4) orthogonal array (OA) design of experiments to study the effect of pretreatment parameters (moisture content, ozone concentration, ozone/oxygen flow and particle size) on the generation of inhibitory compounds and on the composition of hydrolysates of ozonated-washed samples. Ozone concentration resulted the highest influence process parameter on delignification and sugar release after washing; while, for inhibitory compound formation, moisture content also had an important role. Ozone expended in pretreatment related directly with sugar release and inhibitory compound formation. Washing detoxification was effective, providing non-inhibitory hydrolysates. Maximum glucose and xylose release yields obtained were 84% and 67%, respectively, for ozonated-washed SCB. Sugar concentration resulted in the decisive factor for biofuels yields. Ethanol production achieved an 88% yield by Pichia stipitis, whereas Clostridium acetobutylicum produced 0.072gBUTANOL/gSUGAR and 0.188gABE/gSUGAR, and, Clostridium beijerinckii 0.165gBUTANOL/gSUGAR and 0.257gABE/gSUGAR.

Abstract  A vapor-compression refrigeration cycle typically uses standard refrigerants as the working fluid. Traditional refrigerants, however, have been associated with Ozone level Depletion Potential (ODP) and significant Global Warming Potential (GWP). An innovative cooling technology has been investigated using sonic multi-phase flow in a critical-flow nozzle to create a low-pressure and low-temperature region for heat absorption. The strength of the new technology is its potential to produce cooling using water and/or other working fluids with low ODP and GWP. While the full potential for using water as the working fluid may not be fully-realized, because of property limitations still under investigation, water still provides a very useful media for investigating the underlying cavitation phenomena for the development of the new technology.

As part of ongoing research into the potential cooling capacity of the cavitation phenomena, cavitation in a converging-diverging nozzle is being investigated using water as the working fluid. Cavitation in a fluid is the formation of the vapor phase from the liquid phase by reduction in the pressure of the fluid below its saturated vapor pressure. Due to the constricting nature of the throat of a converging-diverging nozzle, the liquid water velocity at the throat is increased and the local absolute pressure can drop to values below the saturated vapor pressure of water at a given temperature; thus, causing the fluid to cavitate.

The effect of water temperature on both the onset of the cavitation within the nozzle, and the resulting length of the cavitation region within the nozzle, are the subject of the current paper. Flow Visualization using a high speed digital camera under these different operating conditions was aimed at investigating the region of cavitation onset, which also appears to be associated with the region of boundary layer separation just downstream of the throat of the nozzle. The length of the two phase region at different operating temperatures was measured and it was observed that as the temperature of the fluid was increased, the length of two-phase region before it condensed into single-phase liquid became longer. Experimental results and analysis are presented which also show that near the onset of cavitation, the flowrate can likely go well beyond a choking condition without cavitating, and can remain in this metastable state for an extended amount of time before nucleating (cavitating) into a stable state. In particular, analysis indicates that significantly negative absolute pressures can likely be achieved within the nozzle, suggesting the presence of tension in the liquid phase just prior to cavitation.

Abstract  Microplasma has the advantage of reducing the discharge voltage compared with other atmospheric plasmas. It is generated at atmospheric pressure at only around 1.0 kV since its discharge gap is on the order of micrometers. The experiment was performed with air and argon as the process gases, to confirm the influence of different radical species in the microplasma, on the bacteria cultures. The process gas flows through the parallel plate electrodes with holes which were covered with dielectric material and energized at about 1.0 kV. The active species generated by the dielectric-barrier discharge microplasma flows toward the exposed Escherichia coli on the agar media at a distance of 2 mm from the electrodes. The process is known as remote microplasma sterilization method. Microplasma generated by both air and Ar is effective for sterilization. Observation by the scanning-electron-microscope images shows that the E. coli had a shrunk shape after the microplasma treatment.

Abstract  In this paper, we propose a self-assembled microlens on top of light-emitting diodes (LEDs) based on hydrophilic effect under ultraviolet (UV)/ozone treatment to improve extraction efficiency and to increase viewing angle. The LED chip was encapsulated by polydimethylsiloxane (PDMS) (n = 1.44) before the fabrication process of microlens. The microlens was made of transparent negative photoresist SU-8 (n = 1.63). The SU-8 photoresist became more hydrophilic after UV/ozone treatment. After hydrophilic zones were produced by using shadow masks and UV/ozone, the substrate with hydrophilic zones was dipped in and out of diluted SU-8 photoresist solution with slow and constant velocity. Meanwhile, a 200-mu m microlens was formed by self-surface tension and cohesion of diluted SU-8. Finally, microlens was hardened after UV curing. This approach is cost effective and low time-consuming. It did not require photo masks, heating, or etch-transfer processes. It's a new fabrication method that can be easily applied to opto-electronic devices. Integrated with LED, microlens can improve extraction efficiency 28% in total power and increase viewing angle 17 degree.

Abstract  A novel concept for the preparation of multiphase composite ceramics based on demixing of a single ceramic precursor has been developed and used for the synthesis of a dual-phase H2 -permeable ceramic membrane. The precursor BaCe0.5 Fe0.5 O3-δ decomposes on calcination at 1370 °C for 10 h into two thermodynamically stable oxides with perovskite structures: the cerium-rich oxide BaCe0.85 Fe0.15 O3-δ (BCF8515) and the iron-rich oxide BaCe0.15 Fe0.85 O3-δ (BCF1585), 50 mol % each. In the resulting dual-phase material, the orthorhombic perovskite BCF8515 acts as the main proton conductor and the cubic perovskite BCF1585 as the main electron conductor. The dual-phase membrane shows an extremely high H2 permeation flux of 0.76 mL min(-1)  cm(-2) at 950 °C with 1.0 mm thickness. This auto-demixing concept should be applicable to the synthesis of other ionic-electronic conducting ceramics.

Abstract  To solve some problems existing in PZT films, such as: large residual stresses, interface diffusion, and lead loss, etc., which were caused by high post-annealing temperatures, and to obtain thin films with high-preferred orientation and uniform size grain and dense microstructure, different technological conditions of microwave plasma assisted post-annealing had been pilot studied. X-ray diffraction was used to analyze the crystal structures of the films. Transmission electronic microscope was used to analyze the surface and the interface morphology of the films. Ferroelectric properties were showed by measuring the remnant polarization and the leakage current dependence of electric field. The results indicated that it was good for reducing lead loss and annealing temperature of PZT films by microwave plasma assisted annealing. Ferroelectric properties of the film could also be enhanced by this pilot annealing method.

Abstract  Highly-ordered and conformal Ni nanotube arrays were prepared by combining atomic layer deposition (ALD) in a porous alumina matrix with a subsequent thermal reduction process. In order to obtain NiO tubes, one ALD NiCp2/O3 cycle was repeated 2000 times. After the ALD process, the sample is reduced from NiO to metallic Ni under hydrogen atmosphere. Their magnetic properties such as coercivity and squareness have been determined in a vibrating sample magnetometer in the temperature range from 5-300 K for applied magnetic fields parallel and perpendicular to the nanotube axis. Ni nanotubes synthesized by ALD provide a promising opportunity for potential applications in spintronics, data storage and bio-applications.

Abstract  A numerical model including 29 reactions and 11 species is developed to investigate the spatial-temporal distributions of species and electric field in oxygen parallel-plate positive pulsed dielectric barrier discharge for ozone generation. Electron energy conservation equation is coupled to electron continuity equation, heavy species continuity equation and Poisson's equation. The spatial-temporal distributions of species and electric field are obtained at electron avalanche and during streamer propagation. The results show the dominant positive ion, negative ion and excited species are O-2(+), O-3(-) and O-2 ((1)Sigma(+)(g)), respectively. The average streamer propagation velocity is about 5.56 x 10(4) m/s. Overall electron density almost increases exponentially but with a violent oscillation in the vicinity of anode at electron avalanche. Electron density increases at first and then declines in the vicinity of anode and streamer channel during streamer propagation, and increases gradually in streamer head with the development of streamer, as well as reduces sharply to almost zero near cathode. Electron density almost remains constant in whole streamer channel at any one moment. Other species have a similar spatial-temporal distribution. (C) 2015 Elsevier Ltd. All rights reserved.

Abstract  The purpose of this study is to compare the efficiency of ozonation and the hydrogen peroxide-ozone process for the removal of cyanide from coking wastewater. The most efficient oxidation process is combined with coagulation-flocculation-decantation and lime-soda ash softening pretreatments. The oxidation in aqueous solution and industrial wastewater (at pH 9.5-12.3) by O3 was carried out using a range of concentration of consumed O3 from 10 to 290 mg/L. A molar ratio of H2O2/O3 from 0.1 to 5.2 with different concentrations of O3 constants was used for the H2O2-O3 process. The maximum cyanide removal obtained in coking wastewater was 90% using a mass ratio of O3/CN(-) of 9.5. Using lower concentrations of O3, cyanide is not removed and can even be generated due to the presence of other cyanide precursor organic micropollutants in the industrial matrix. The concentration of O3 is reduced to half for the same cyanide removal efficiency if the pretreatments are applied to reduce the carbonate and bicarbonate ions. The cyanide removal efficiency in coking wastewater is not improved if the O3 is combined with the H2O2. However, the preliminary cyanide removal treatment in aqueous solution showed an increase in the cyanide removal efficiency for the H2O2-O3 process.

Abstract  New zirconium (Zr) based organometallic catalysts for direct olefin epoxidation using O-2 as oxidant without coreductant were introduced in a previous computational study (T. A. Manz and B. Yang, RSC Adv., 2014, 4, 27755-27774). In this paper, we use density functional theory (DFT) to study three Hf-based catalysts with the same bis(bidentate) ligands as the preceding Zr-based catalysts: (a) the diimine ligand N(Ar)-CH-CH-N(Ar) aka NCCN, (b) the imine-nitrone ligand N(Ar)-CH-CH-N(Ar)-O aka NCCNO, and (c) the dinitrone ligand O-N(Ar)-CH-CH-N(Ar)-O aka ONCCNO [Ar = -C6H3-2,6-Pr-i(2)]. Complete reaction cycles and energetic spans (i.e., effective activation energies for the entire catalytic cycle) are computed for propene epoxidation. For Hf_NCCNO and Hf_ONCCNO, the reaction cycles are similar to the Zr-based analogs and the formation of eta(3)-ozone intermediates is still crucial. Hf_ONCCNO has a large enthalpic energetic span (60.4 kcal mol(-1)) due to forming inert octahedral complexes as the catalyst resting state. Our calculations predict an energetic span >= 40 kcal mol(-1) for Hf_NCCN, which indicates it will not be a good catalyst. Computed enthalpic energetic spans of similar to 30 kcal mol(-1) are achieved for the Hf_NCCNO and Zr_NCCNO catalysts; however, transfer of allylic hydrogen from the reaction product forms a low energy deactivation product. Therefore, the Hf_NCCNO and Zr_NCCNO catalysts are only suitable for direct epoxidation of alkenes that do not have any allylic hydrogen atoms. As an example of an alkene with no allylic hydrogens, we computed enthalpic energetic spans (kcal mol(-1)) for direct ethylene epoxidation of (a) 25.0 for Hf_NCCNO, (b) 30.2 for Zr_NCCNO, and (c) 52.7 for Zr_NCCN.