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Nodularity is one of the key indexes to evaluate compacted graphite cast iron, and the vermicularizing effect is related to the active oxygen of molten iron. In this study, the active oxygen including oxygen activity and oxygen potential was measured by NSP3603 with disposable oxygen probe, and the nodularity was measured by quantitative metallography. The influence of active oxygen on vermicularizing effect and the influence of temperature on active oxygen during the fading process were analyzed and discussed. The results showed that the smaller the oxygen activity and oxygen potential are, the higher the nodularity becomes. When the oxygen activity is 0.1 ppm and the oxygen potential is − 237 mV, it has the best deoxidation effect, and the nodularity is 87%, which belongs to ductile cast iron. When the oxygen activity is more than 0.8 ppm and the oxygen potential is higher than – 166 mV, it has suitable deoxidation effect, and the nodularity is less than 15%. The oxygen potential of – 107 mV and oxygen activity of 0.8 ppm are taken as thresholds for the vermicularizing state. If lower than those, the vermicularizing effect remains unchanged. Once higher than those, the vermicularizing effect declines. A method was proposed to evaluate the vermicularizing effect of molten iron by the oxygen activity αO, oxygen potential EO and temperature TC after ladle treatment, and the corresponding criteria were established. Namely, if αO < 0.1 ppm, the nodularity is more than 80%; if 0.1 ppm < αO≤ 0.3 ppm, the nodularity is 45–80%; if 0.3 ppm< αO ≤0.6 ppm, the nodularity is 30–45%; if 0.6 ppm< αO ≤0.8 ppm, the nodularity is 20–30%; if 0.8 ppm< αO< 1.3 ppm, the nodularity is below 20% and mostly lower than 15%; if αO ≥ 1.3 ppm, the nodularity suddenly increases and the tendency to precipitate flake graphite increases. According to the criteria, the nodularity of molten iron can be evaluated by oxygen activity αO, oxygen potential EO and temperature TC after the ladle treatment. [ABSTRACT FROM AUTHOR]

In the LD–RH–CC process for producing low-carbon low-silicon steel, the cleanliness level of the slab was studied by optimizing the compositions of the refining slag and oxygen blowing flow in trial heats through judicious control. In order to realize RH without oxygen blowing, the oxygen content of molten steel should reach 475–525 ppm before RH degassing to guarantee that the free oxygen is in the range of 100–150 ppm after the carbon–oxygen reaction. When the slag compositions were controlled to CaO = 41–50 wt-%, Al2O3 = 29–36 wt-%, SiO2 = 5–11 wt-% and MgO = 6–10 wt-% in the RH treatment without feeding calcium, the total oxygen content in the plate was 18 ppm, and the nitrogen content decreased to 17 ppm in the improved process. The micro-inclusions in the slab mainly consisted of MgO–Al2O3–(MnS) and Al2O3–(MnS), and the particle size was mainly concentrated below 3 μm. The average total amount of large electrolytic inclusions in the slab was 1.384 mg kg steel−1. The large inclusions were mainly SiO2, Al2O3, SiO2–Al2O3–(K2O), and MgO–Al2O3. [ABSTRACT FROM AUTHOR]

The article deals with the solution of an urgent problem related to the process of filtration refining of ferroalloys. Based on the data obtained, it was found that combining the filtration process with casting ensures the flow of refined melt directly into the mold cavity and partial or complete elimination of secondary oxidation. To identify the underlying mechanism of filtration refining, the interaction of liquid metal with the filter in its separate pore channel was simulated. The main technological parameters of the process under consideration are calculated and practically confirmed.

Simultaneously harnessing cation and anion redox activities in the cathode is crucial for the development of high energy-density lithium-ion batteries. However, achieving long-term stability for both mechanisms remains a significant challenge due to pronounced anisotropic volume changes at low lithium content, unfavorable cation migration, and oxygen loss. Here, we demonstrate exceptionally stable cation and anion redox behavior in a metastable, cobalt-free layered oxide, Li 0.693 [Li 0.153 Ni 0.190 Mn 0.657 ]O 2 (LLNMO). After 50 cycles at 50 mA/g (~0.2 C), the cathode retains 97.4 % of its initial capacity (222.4 mAh/g) with negligible voltage decay. This remarkable stability is attributed to its metastable O6-type structure (R-3m symmetry) with unique local geometry. The face-sharing connectivity between lithium layers and alternating transition metal (TM) layers effectively suppresses TM migration-induced voltage decay during anion redox. Additionally, the structure balances interlayer cation/cation and anion/anion repulsions, resulting in minimal expansion and contraction during de-/lithiation (<2.3 % along the c-axis) and excellent structural reversibility. These findings highlight that layered oxides with a metastable framework are promising cathode candidates for next-generation ultra-high-energy lithium-ion batteries., (© 2025 The Author(s). Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

Elemental doping is widely used to improve the performance of cathode materials in lithium-ion batteries. However, macroscopic/statistical investigation on how doping sites are distributed in the material lattice, despite being a key prerequisite for understanding and manipulating the doping effect, has not been effectively established. Herein, to solve this predicament, a universal strategy is proposed to quantitatively identify the locations of Al and Mg dopants in lithium-rich layered oxides (LLOs). Solid evidence confirms that Al prefers to occupy the transition metal (TM) layer, while Mg evenly occupies both TM and Li layers. As a result, Mg significantly reduces the thickness of LiO 2 slabs at room temperature, which will increase the energy barrier of oxygen activation and enhance the structure stability of LLOs. The suppressed oxygen activity in Mg-doped LLO can be kinetically unlocked at 55 °C. The different characteristics of Al and Mg enlighten an Al/Mg co-doping strategy to optimize LLOs, which significantly improves the cycle performance while lifting the capacity. These insights from the quantitative identification of doping sites shed light on the manipulation of doping effects toward better cathodes., (© 2024 Wiley‐VCH GmbH.)

The HIsarna process is one of the emerging low‐CO2 ironmaking processes that could help the steel industry in achieving their carbon footprint goals. HIsarna hot metal contains 3–4 times more sulfur than hot metal from blast furnaces (BFs). Therefore, a literature study, a thermodynamic analysis, and plant data analysis from Tata Steel, IJmuiden, are used herein to investigate the consequences of HIsarna hot metal for the current hot metal desulfurization process. Although the high sulfur concentration and low temperature of HIsarna hot metal lead to a higher total reagent consumption, compared with desulfurization of BF hot metal, the specific magnesium consumption decreases. The higher oxygen concentration in HIsarna hot metal only leads to a small increase in reagent consumption. [ABSTRACT FROM AUTHOR]

The article deals with the solution of an urgent problem related to the process of filtration refining of ferroalloys. Based on the data obtained, it was found that combining the filtration process with casting ensures the flow of refined melt directly into the mold cavity and partial or complete elimination of secondary oxidation. To identify the underlying mechanism of filtration refining, the interaction of liquid metal with the filter in its separate pore channel was simulated. The main technological parameters of the process under consideration are calculated and practically confirmed. [ABSTRACT FROM AUTHOR]

The problem of ensuring an error of no more than 1% in monitoring the coolant flow rate in the piping of the first loop of the reactor in nuclear power plants is examined. A method for measuring the coolant flow rate based on recording the γ-radiation during the variation of the oxygen activity of the coolant is proposed. A measurement device is created for recording bursts of γ-radiation which contain probes based on fiber optics and ways of placing it on the piping are described. To implement the proposed method, an optical flowmeter has been developed for monitoring the coolant flow in laminar and turbulent flow regimes at different temperatures. An optimum doping for the core of the fiber optic with germanium oxide is established for measurements of the coolant flow rate for different intensities of the oxygen activity. A method is proposed for recovery of the transmission of the optical fiber in measurements of the coolant flow rate in the presence of γ-radiation. A technique for measuring the coolant flow rate is examined in detail and features of its implementation are noted. Results from a study of the optical flowmeter on a test stand are presented. [ABSTRACT FROM AUTHOR]

The oxidation of benzene, fluorobenzene, chlorobenzene, and phenol in the presence of O2 and N2O on HZSM-5 type zeolite with Si/Al = 24 was studied by EPR spectroscopy. It was shown that the thermal decomposition of nitrous oxide on zeolite forms molecular and chemisorbed atomic oxygen. It was found that the catalytic oxidation of benzene, fluorobenzene, chlorobenzene, and phenol under the action of О2 and N2O proceeds at Lewis acid sites and leads to the formation of phenoxyl radical cations with characteristic g factors and hyperfine structure of the EPR spectrum. [ABSTRACT FROM AUTHOR]

This paper is focused on the specifics of amperometric oxygen (O2) measurements in biological media (cultivation media, reaction mixtures, media designed for isolated cellular and subcellular structures) and other complex media using Clark-type electrodes. Specifically, the impact of the qualitative and quantitative composition of liquid media on the readings of Clark electrodes is considered. Using sucrose, sorbitol, NaCl and phosphate buffer as examples, it has been shown that, provided the content of dissolved O2 is constant, an increase in the content of concomitant to O2 substances in the test medium results in an increase of the signal of the Clark electrode located in this medium. On the basis of the obtained and published data, the effect of the qualitative and quantitative composition of media on the readings of Clark electrodes is evaluated. In its turn, the very effect of media composition on Clark electrodes readings can be explained by the fact that in reality Clark electrodes measure the activity of dissolved O2, which usually increases with an increase in the content of concomitant to O2 substances. Since Clark electrodes measure the activity rather than the true O2 content in media and the ratio between the activity and true O2 content is often unknown, the issue regarding the calibration of Clark electrodes has been also considered in this study. It is noted that the methods of adding known amount of O2 to liquid media (the Hill reaction, catalase reaction, or injection of a micro portion of water saturated with pure O2), which were applied in this work to demonstrate the effect of media composition on the Clark electrode readings, can be used to calibrate the Clark electrodes in units of the true O2 content, and, thus, to take into account the influence of the media content on the readings of these O2-sensors when it is necessary. It is suggested that the calibration based on the addition of an O2-saturated micro-portion of water or, if necessary, O2-saturated micro-portion of another suitable liquid to the medium with the Clark electrode is, due to its almost unlimited applicability and other advantages, the most satisfactory way of calibration. The introduction of this calibration method into scientific practice can make quantitative O2-measurements with Clark electrodes more accurate in many difficult cases. [ABSTRACT FROM AUTHOR]

The method of instant EMF fixation has been used to determine the activity of oxygen in model Ni melts containing up to 0.001–0.20 wt % La and Ce. It is shown that, at PAr = 0.1 MPa and 1560°C, when cerium is introduced into the melt, the oxygen activity is 4.7 times lower than when deoxidizing with lanthanum. SEM investigation shows that the composition of nonmetallic inclusions in molten Ni deoxidized by La and Ce indicates a stronger bonding of Ce with oxygen than with La and a stronger bonding of La with sulfur than with Ce. [ABSTRACT FROM AUTHOR]

Precise control of inclusion and molten steel compositions during ladle-furnace refining is important to obtain high-quality steel. Mass-transfer behavior affects these compositions. A model was developed to investigate the mass transfer occurring between molten steel, slag, inclusions, and the refractory during ladle-furnace refining, using two-film theory to describe the reactions. A coupled-reaction model based on the CaO–Al2O3–MgO–SiO2–FeO–P2O5 slag and Mn–Si–Al–Ca–Mg–P–S–O steel systems was applied to describe the reactions between molten steel and slag; the reactions between the refractory lining and slag or steel were described using average industrial erosion rate data. The model was used to calculate changes in the compositions of molten steel and slag, oxygen activity at the slag–molten steel interface, and composition of the inclusions. The calculated results agreed with operational results for a 100 t ladle furnace at the Tangsteel plant in China.

[Display omitted] • Ce doping improved oxygen species mobility and reduced carbon deposition. • The intervening of Ce followed by Ni facilitated the formation of oxygen vacancies. • Optimized parameters for plasma-catalytic benzene steam reforming were obtained. • Preventing deep benzene cracking to form graphitic carbon was critical. Non-thermal plasma (NTP) coupled Ni-based catalysts show significant potential in reforming of biomass tar for syngas production. Carbon deposition on catalysts remains a troubling problem. Ce doping can contribute to the improvement of oxygen vacancies and oxygen activity, which is expected to solve this challenge. In this study, Ce-doped Ni-based catalysts with HAP as support have been prepared. Benzene was selected as a tar model and the effects of Ni/Ce, steam to carbon ratio (S/C), reaction temperature, discharge power, Ni/Ce intervention order and catalysts preparation method on catalytic activity and stability were investigated in NTP-catalytic system. The results show that Ni3/Ce5-HAP-C exhibits the best catalytic activity at a reaction temperature of 450 °C, an S/C of 1.6, and a discharge power of 86 W with benzene conversion of 94.99 %, total gas yield of 3501.20 mL/g benzene and energy efficiency of 8.75 g/kWh. An increase in Ce proportion significantly enhances the reducibility of the metal oxides and the mobility of the oxygen species, and effectively reduces the catalyst carbon deposition. The increase in temperature significantly enhances the catalyst reactivity and selectivity. The order of metal intervention of Ce followed by Ni proves to be favorable for the Ni-Ce bimetallic catalysts, and the first intervening Ce is able to enhance the lattice oxygen activity and the dispersion of Ni metal. Characterization of the spent catalysts indicates that graphitic carbon is the main type of carbon deposition, and reducing the conversion of benzene and its intermediates into graphitic carbon is crucial to enhance the stability of the catalysts. [ABSTRACT FROM AUTHOR]

This work considers the effect of chromium surface segregation for polycrystalline Cr-doped TiO2 on surface vs. bulk defect disorder. It is shown that annealing of Cr-doped TiO2 (0.04 at% Cr) in the gas phase of variable oxygen activity at 1273 K results in a gradual transition in the valence of chromium at the surface from predominantly Cr3+ species in reduced conditions, p(O2) = 10−12 Pa, to comparable concentrations of both Cr3+ and Cr6+ species in oxidising conditions, p(O2) = 105 Pa. The reported data is considered in terms of defect equilibria leading to the formation of positively and negatively charged chromium in both the cation sub-lattice and interstitial sites. The derived theoretical models represent the effect of oxygen activity on the surface charge and the resulting electric field leading to migration mechanism of charged chromium species. [ABSTRACT FROM AUTHOR]

Oxygen is an element that is first purposely brought into the steel melt to remove some unwanted elements or to reduce their concentration (oxidation). In the made cast steel there is on the contrary necessary to reduce the oxygen content with the use of deoxidation to such a level in order to avoid a reaction with carbon with the formation of CO bubbles. Concentration of oxygen in steel before casting is given, in particular, by the manner of metallurgical processing and the used deoxidation process. Oxygen is found in molten steels both as chemically bound in the form of oxides and in the form of oxygen dissolved in the solution – the melt. Chemical composition of the melt strongly influences the activity of oxygen dissolved in the melt and further on the composition of oxidic inclusions forming in the melt during the reaction with oxygen. In the Fe-C-Cr-Ni based alloys in the reaction with oxygen greatly participates also chrome, whose products are often in solid state and they are the cause of forming such defects as e.g. oxidic films.

Deoxidation of steel with carbon under reduced pressure is often used for increasing the steel purity. Suitable units for this purpose in foundries are vacuum induction furnaces. Possibilities of increasing the steel purity by deoxidation with carbon in the vacuum induction furnace were studied for the steel for the petrochemistry of specific composition 25Cr/35Ni. The charge composed of the return material only was melted in the air. During melting the charge oxidized and the oxidizing slag formed. Chemical composition of steel, morphology, chemical composition of inclusions in the steel and chemical composition of slag after vacuuming were studied on the basis of samples taken before and after vacuuming. Temperature and oxygen activity were measured before and after vacuuming. Globular inclusions with dominant content of silicon and manganese were observed in steel before and after vacuuming. Contents of total oxygen in steel didn’t change significantly during vacuuming. On the basis of composition of inclusions and measured oxygen activity the activity of Cr2O3 in inclusions was calculated. A slag sample was taken after vacuuming and equilibrium oxygen activity in steel with regard to the Cr2O3 content in the slag was estimated from the slag composition. Equilibrium oxygen activity in relation to the Cr2O3 content in the slag was higher than equilibrium activity measured in the steel. For this reason it is not possible, under the studied conditions, to decrease oxygen content in steel during vacuuming.

The contribution summarises the results of application of thermodynamic calculation obtained from oxygen activities measurements in cast irons with various type of graphite microstructure. The results were used to find the relationship between natural logarithm of oxygen activities and reverse value of thermodynamic temperature 1/T.From obtained regression line the calculation of oxygen activities value for significant temperature of molten metal was achieved. Each material has its proper typical oxygen activities range for analysing and controlling graphite quality. Practical implication was successfully tested in a Czech foundry producing centrifugally poured cast iron rolls designed for hot strip mills with spheroidal graphite iron core.

In this work, the contact angle has been studied of a type of a low-alloyed steel on two composite ceramics used during the aluminothermic welding of rails to provide missing data for multiphase flow simulations. A reference contact angle measurement of thermite steel on a 99.5% pure alumina surface from Co. Friatec has been conducted. The results were obtained in a custom build hot stage microscope by the sessile drop technique. Measurements have been carried out in a temperature range from liquidus of thermite steel up to 1978.9 K. The results are serving as boundary conditions for multiphase flow CFD simulations of the crucible discharge and mould filling with thermite steel, alumina slag and air during the aluminothermic welding of rails. With this work we want to provide CA values for these special materials to advance the numerical results closer to the reality of railway welding. On waterglass-bonded materials, the contact angle was analysed near melting point at 1723 K. Contact angles on waterglass-bonded SiO2 substrates with high and without Al2O3 content are obtained as (134.0 ± 5.6)° and (131.4 ± 3.5)° respectively. Measurements on the pure reference Al2O3 substrate have been found to be linearly decreasing in a temperature range between 1723.2 K and 1836.7 K and at 1978.9 K a contact angle of (102.7 ± 3.0)° has been obtained. [ABSTRACT FROM AUTHOR]

The present chain of five papers considers the concept of solar-to-chemical energy conversion using TiO2-based semiconductors. The series reports the effect of chromium on the key performance-related properties of polycrystalline TiO2 (rutile), including electronic structure, photocatalytic activity, intrinsic defect disorder, electrochemical coupling and surface versus bulk properties. This work considers the effect of oxygen activity on segregation-induced surface versus bulk composition for both polycrystalline and single-crystal specimens of Cr-doped TiO2. It has been documented that annealing of Cr-doped TiO2 at 1273 K in oxidising conditions results in an enrichment and depletion of the surface layer with chromium. It is shown that the segregation-induced enrichment factor for single crystal is substantially larger than that for polycrystalline specimen. The effect is considered in terms of a theoretical model showing that surface segregation of solute in polycrystalline specimen is encumbered by its segregation to grain boundaries. It is also shown that the segregation-induced enrichment is profoundly influenced by oxygen activity. The new insight of this work involves (i) the determination of well-defined chromium segregation in Cr-doped TiO2, including single-crystal and polycrystalline specimens, after annealing in the gas phase of controlled oxygen activity, and (ii) identification of the predominant driving force of segregation of chromium in Cr-doped TiO2 that is based on electrostatic interactions between the low-dimensional surface structure (LDSS) and electrically charge segregating species.ᅟ [ABSTRACT FROM AUTHOR]

The present chain of five papers considers the concept of solar-to-chemical energy conversion using TiO2-based semiconductors. The series reports the effect of chromium on the key performance-related properties of polycrystalline TiO2 (rutile), including electronic structure, photocatalytic activity, intrinsic defect disorder, electrochemical coupling and surface vs. bulk properties. The present work reports the effect of oxygen activity in the oxide lattice on photocatalytic activity of pure and Cr-doped TiO2 (0.04 at% Cr). Processing of specimens included annealing at 1273 K in the gas phase of controlled oxygen activity in the range 10−12 Pa < p(O2) < 105 Pa. We show that the increase of oxygen activity results initially in a decrease of photocatalytic activity, minimum around the n-p transition point, and then increase assuming maximum at p(O2) = 105 Pa. The obtained results are considered in terms of a theoretical model that explains the effect of defect disorder on the reactivity of TiO2 with water. The minimum of the photocatalytic activity corresponds to the n-p transition point. The maximum of performance at high p(O2) is determined by increased concentration of titanium vacancies forming surface active sites. [ABSTRACT FROM AUTHOR]

[Display omitted] • A more cost-effective and eco-friendly modification for enhancing oxygen activity. • Fragmented flaky structure endowed LaFeO 3 with more robust oxygen activity. • The gas yield and carbon conversion in the BCLG stage increased by 22.7% and 21.1%. • Residual char played a predominant role in the splitting stage. • Reaction mechanism of LaFeO 3 in BCLG coupled with CO 2 /H 2 O splitting was analyzed. Considering that the conventional modification of metal doping may bring excessive cost escalation and more pollution, for the sol–gel method, a more cost-effective and eco-friendly modification method was proposed to enhance the oxygen activity of LaFeO 3 and its doped oxygen carriers (OCs). In this work, LaFeO 3 OCs with fragmented flaky structure was prepared by modification of adjusting the sol to weak alkalinity with ammonia and adding the complexing agent ethylene glycol. Then, it was applied in Biomass chemical looping gasification (BCLG) coupled with CO 2 /H 2 O splitting to produce high-quality syngas and achieve cascade conversion of carbon in biomass, and its performance and reaction mechanism were investigated by fixed bed test. The results showed that the fragmented flaky structure endowed the LaFeO 3 OCs with more robust oxygen activity, thus realizing efficient lattice oxygen migration which increased the gas yield of BCLG stage from 695.6 mL/g to 851.2 mL/g at 900 °C, and the carbon conversion and gasification efficiency reached 65.6% and 64.4%, respectively. Despite the predominant role of residual char in the gas generation of splitting stage, the reduced OCs still possesses exceptional CO 2 and H 2 O splitting ability. Among them, CO 2 splitting was mainly carried out by the activation of Fe0 and alkaline active sites from the reduced OCs, while H 2 O splitting depended more on the decomposition of H 2 O molecules by oxygen vacancies. Moreover, this OCs exhibited outstanding stability in 10 cycles, and the total gas yield in two stages was consistently maintained around 1030.1 mL/g and 1069.6 mL/g, respectively. This work found that the LaFeO 3 OCs with fragmented flaky structure is a prospective material for chemical looping technology. [ABSTRACT FROM AUTHOR]

The possibilities of obtaining a good process control in order to reach a good cleanliness of the steel were studied based on plant trials. Steel and slag samples were taken from two steel grades with a slightly different composition, but with similar processing conditions. Thereafter, the chemical compositions of the steel and slag samples were determined. The results show that the sum of the FeO and MnO was found to be a clear indicator for when reoxidation had taken place. No conclusive indicator was found to predict the extent of slag carry-over from the electric arc furnace. However, most of the variation in deoxidation seem to originate from the accuracy of the slag raking. Steel grades with low amounts of deoxidisers such as C and Si naturally were found to result in higher oxygen contents at the start of deoxidation. Furthermore, calculations of oxygen activities in the steel melt were made and the results were compared to measurements with varying results. Overall, the results indicate that calculation of oxygen activities with multivalence slag species such as Fe and Cr requires additional measurements to obtain accurate results. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin University of Science & Technology is the property of Journal of Harbin University of Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Metallophysics & Advanced Technologies / Metallofizika i Novejsie Tehnologii is the property of G.V. Kurdyumov Institute for Metal Physics, N.A.S.U and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of the study was to evaluate the effect of β-endorphin on oxygen activity of polimorphonuclear neutrophils and to investigate the total antioxidant status of blood serum in rats subjected to chronic treatment with methimazole. The study was carried out on 15 male Wistar rats weighing 270-290 g, divided into two groups. The animals from experimental group were administered a 0.05% drinking water solution of methimazole. The oxygen activity of peripheral blood neutrophils was examined using a modified RBA test. The extra-receptor effect of β-endorphin on the respiratory burst of neutrophils was evaluated. The incubation of neutrophils in the presence of phorbol myristate acetate (PMA) in the control group caused a nearly threefold increase in the oxygen activity of the cells compared to the control. Slightly higher values were obtained after addition of β-endorphin at the concentration of 10-6. Lower concentrations of this opioid (10-8 and 10-10) also stimulated oxygen activity but at a lower level than PMA. Naloxone did not affect the oxygen activity only when using β-endorphin in the concentration of 10-6. Naloxone and β-endorphin in the concentrations of 10-8 and 10-10 evoked a linear decrease in the oxygen activity of neutrophils, below the values obtained for PMA. The obtained results suggest that methimazole significantly modulates the generation of reactive oxygen species under the influence of β-endorphin, which stimulates the respiratory burst via the receptor pathway and inhibits it via the extra-cellular pathway. Methimazole also stimulates the anti-free radical defence.

The influence of pO 2 on the base oxide formed on 304 L stainless steel has been investigated at 600 °C. The alloy was exposed in 5%O 2 -95%N 2 and 10%H 2 -20%H 2 O-Ar atmospheres and the initial stages of oxidation were analysed by TEM and EDX. In both environments, the thin scale consists of a Cr-rich oxide overlaid by a FeCrMn oxide. However, the subscale formed in H 2 -H 2 O is richer in Cr compared to the 5%O 2 -95%N 2 case (∼90 cation% and ∼70 cation% respectively). The findings are in good agreement with thermodynamic calculations and can explain breakaway oxidation of marginal chromia forming steels in H 2 -H 2 O. • Initial oxidation stage (1 h) of 304 L stainless steel in high and low a(O 2) environments. • Dual oxide layer formed in both environments: Fe-rich at the oxide-gas interface and Cr-rich at the metal-oxide interface. • Cr-rich oxide layer at the metal-oxide interface formed in H 2 +H2O has higher Cr content compared to the one formed in O 2 -N 2. [ABSTRACT FROM AUTHOR]

In thermodynamic calculations, the activity of oxygen in equilibrium with Al, Mn, and Ce is determined for four melts of pipe steel. Pure gaseous oxygen under pressure is adopted as the standard state of oxygen dissolved in liquid metal. The actual (above-equilibrium) activity of oxygen is calculated on the basis of electrochemical measurements in liquid steel by oxygen sensors. For the melts, the difference between the actual and equilibrium chemical potentials, which may be regarded as the factor that drives reduction, is 14-20 kJ/mol. The conditions for microalloying of the melt with cerium are assessed. [ABSTRACT FROM AUTHOR]

Industry trials of slag-washing desulfurization in LD tapping process are performed to study the influence of silicon on desulfurization of Al-killed steel using CaO-Al2O3 slag contained FeO and MnO. Influence of silicon on desulfurization is found to be great, while the influences of aluminum and manganese on desulfurization are negligible. Oxygen activity at slag-steel interface together with the (FeO + MnO) content in slag, decreased with the rise of silicon content, which is considered as the main reason of different desulfurization efficiencies between Si-free steel and Si-containing steel. Oxygen activity at slag-steel interface is reduced more sharply by increasing the silicon content than that by increasing the aluminum content. As a result, desulfurization efficiency can be enhanced significantly with the rise of silicon content, rather than the aluminum content. Furthermore, the influence of silicon on desulfurization can be magnified if the slag contained FeO and MnO, while negligible for the slag with few FeO and MnO. [ABSTRACT FROM AUTHOR]

Because of good high temperature conductivity (Mn,Co) 3 O 4 is a promising oxide coating for solid oxide fuel cell interconnect. High-temperature oxidation of Co-Mn alloys at 750 °C and 850 °C at 10 5 Pa oxygen reveals that formation of a continuous (Co,Mn) 3 O 4 spinel layer significantly decreases oxidation rate constant but not the same for the discontinuous spinel layer. Co-40Mn fine grain alloy coatings are prepared by high-energy micro-arc alloying process (HEMAA). Microstructures and compositions after preparation and oxidation were analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). When pre-oxidized under an oxygen pressure of 10 5 Pa at 850 °C for 10 h, Co-40Mn coatings are transformed into the external oxide which is mainly composed of (Co,Mn) 3 O 4 and Mn 3 O 4 . The results disclose Cr outward transport from the stainless steel is significantly suppressed by the as-prepared (Co,Mn) 3 O 4 oxide coatings, when coatings oxidized at 800 °C for 100 h in wet air. The composited spinel coatings have excellent high temperature oxidation resistance and electrical performance. [ABSTRACT FROM AUTHOR]

A Li-rich Mn-based layered oxide cathode (LLO) is one of the most promising cathode materials for achieving high-energy lithium-ion batteries. Nevertheless, the intrinsic problems including sluggish kinetics, oxygen evolution, and structural degradation lead to unsatisfactory performance in rate capability, initial Coulombic efficiency, and stability of LLO. Herein, different from the current typical surface modification, an interfacial optimization of primary particles is proposed to improve the simultaneous transport of ions and electrons. The modified interfaces containing AlPO 4 and carbon can effectively increase the Li + diffusion coefficient and decrease the interfacial charge-transfer resistance, thereby achieving fast charge-transport kinetics. Moreover, the in situ high-temperature X-ray diffraction confirms that the modified interface can improve the thermal stability of LLO by inhibiting the lattice oxygen release on the surface of the delithiated cathode material. In addition, the chemical and visual analysis of the cathode-electrolyte interface (CEI) composition clarifies that a highly stable and conductive CEI film generated on the modified electrode can facilitate interfacial kinetic transmission during cycling. As a result, the optimized LLO cathode exhibits a high initial Coulombic efficiency of 87.3% at a 0.2C rate and maintains superior high-rate stability with a capacity retention of 88.2% after 300 cycles at a 5C high rate.

An improved oxidative production technology for 110Г13Л manganese steel in a 25-t arc furnace is considered. The basic periods of the process are described. The slag conditions in steel production are discussed. The activity of oxygen in the metal is assessed on the basis of practical data regarding the slag composition in the oxidative and reductive periods. The oxygen activity in the metal is plotted as a function of the total content of manganese and iron oxides in the slag. In addition, a method is proposed for determining the required aluminum content for reduction of the metal, so as to obtain the required quantity in the final melt. The influence of the steel's aluminum content on its impact strength is investigated. [ABSTRACT FROM AUTHOR]

This work studied the effect of indium on the semiconducting properties of TiO (rutile) at elevated temperatures (1023-1273 K) in the gas phase of controlled oxygen activity in the range of 10 Pa < p(O) < 10 Pa. The studies were performed using the measurements of thermoelectric power of In-doped TiO (0.4 at.% In) as a function of oxygen activity and temperature. The obtained data indicates that indium is incorporated into the TiO lattice according to the dual mechanism leading to the formation of donors and acceptors in the interface (surface and grain boundary) layer and the bulk phase, respectively. This effect is considered in terms of a quasi-isolated surface layer that differs from the bulk phase in terms of semiconducting properties and the related defect disorder. [ABSTRACT FROM AUTHOR]

The contribution summarises the results of application of thermodynamic calculation obtained from oxygen activities measurements in cast irons with various type of graphite microstructure. The results were used to find the relationship between natural logarithm of oxygen activities and reverse value of thermodynamic temperature 1/T. From obtained regression line the calculation of oxygen activities value for significant temperature of molten metal was achieved. Each material has its proper typical oxygen activities range for analysing and controlling graphite quality. Practical implication was successfully tested in a Czech foundry producing centrifugally poured cast iron rolls designed for hot strip mills with spheroidal graphite iron core. [ABSTRACT FROM AUTHOR]

The present work determined the effect of chromium segregation on surface and near-surface composition of Cr-doped TiO (0.05 at.% Cr) after annealing in oxidising and strongly reducing environments at 1,073 and 1,273 K. The segregation-induced depth profiles were determined by secondary ion mass spectrometry (SIMS). It was observed that annealing in oxidising conditions [p(O) = 10 Pa] and reducing conditions [10 Pa > p(O) > 10 Pa] results in an enrichment and depletion of the surface layer in chromium, respectively. The observed effects may be used for tailoring the surface and near-surface composition in order to impose desired properties. [ABSTRACT FROM AUTHOR]

The redox conditions of an organic system, the cleavage of carboxyl groups, and the reaction of aqueous solutions of cationic and anionic states of microelements are considered. Two types of functional relationships of the microelement content are obtained: with the petrographic composition; and with the concentration of cations and anions in the aqueous solution. These relationships are analyzed. [ABSTRACT FROM AUTHOR]