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The conditions for increasing the hot workability and extending the temperature range for the safe hot working of M2 high-speed steel (HSS) were studied and revealed. This was enabled by combination of two approaches, i.e. results obtained by an analysis of so individual as well as spatial influences of chemical elements on the hot workability using a conditional average estimator neural networks in combination with the results obtained from hot-compression tests that revealed the appropriate soaking conditions. The Latin Hypercube Sampling technique was used to model the uncertainty of the collected data used in the analysis. The obtained results reveal new, surprisingly complex, typically spatial and (highly) non-linear relationships between the chemical elements and the hot workability of M2 HSS, i.e. common mutual influence of carbon, carbide-forming elements as well as elements, i.e. Si, Mn and Co, which indirectly influence the formation of carbides. Further also new allowed upper limits for contents of some harmful elements like S, P, Al, Sb, Cu, Sn, As, Ni, etc. at which transition from higher to lower workability takes place were revealed. Finally, by applying a specially developed procedure for hot-compression tests the appropriate soaking time and temperature were assessed. New findings explain and considerably improve the intrinsic hot workability and extend the temperature range for safe hot working at its upper and lower limits.

In this study, a promising relationship between antibacterial zone and radiation attenuation properties was investigated in Ag2O doped bioactive glasses with a chemical composition of xAg2O–20Li2O–25TeO2-(55-x)B2O3 (where x = 0, 0.5, 1.0, 1.5, and 2.0 mol%). For this aim, a wide-ranging radiation attenuation characterization procedure was performed on Ag2O substituted bioactive glasses. The general-purpose Monte Carlo code MCNPX (v.2.7.0) was used to model bioactive glasses. The mass attenuation coefficients were calculated using a gamma-ray transmission setup. The coefficients obtained were used to determine other important attenuation properties. Finally, for particular behaviors, exposure (EBF) and energy absorption (EABF) build-up factors were calculated for specific attitudes of Ag2O substitutions in bioactive glasses during the interaction process. The results showed that there is direct relationship between Ag2O substitution amount and radiation attenuation properties. In addition to its well-behaviors on inhibition zone against bacterial occurrences, it can be concluded that increasing Ag2O would increase the gamma-ray attenuation properties of studied bioactive glass system. © 2021 The Authors The authors thank for the scholar and research grant under Universiti Putra Malaysia , Taif University Researchers Supporting Project number (TURSP-2020/12), Taif University , Saudi Arabia and Deanship of Scientific Research at King Khalid University for financial support through General Research Project under grant number ( G.R.P/81/42 ).

With the rise of two-dimensional (2D) transition-metal dichalcogenide (TMD) semiconductors and their prospective use in commercial (opto)electronic applications, it has become key to develop scalable and reliable TMD synthesis methods with well-monitored and controlled levels of impurities. While metal-organic chemical vapor deposition (MOCVD) has emerged as the method of choice for large-scale TMD fabrication, carbon (C) incorporation arising during MOCVD growth of TMDs has been a persistent concern-especially in instances where organic chalcogen precursors are desired as a less hazardous alternative to more toxic chalcogen hydrides. However, the underlying mechanisms of such unintentional C incorporation and the effects on film growth and properties are still elusive. Here, we report on the role of C-containing side products of organosulfur precursor pyrolysis in MoS2 thin films grown from molybdenum hexacarbonyl Mo(CO)6 and diethyl sulfide (CH3CH2)2S (DES). By combining in situ gas-phase monitoring with ex situ microscopy and spectroscopy analyses, we systematically investigate the effect of temperature and Mo(CO)6/DES/H2 gas mixture ratios on film morphology, chemical composition, and stoichiometry. Aiming at high-quality TMD growth that typically requires elevated growth temperatures and high DES/Mo(CO)6 precursor ratios, we observed that temperatures above DES pyrolysis onset (â 600 °C) and excessive DES flow result in the formation of nanographitic carbon, competing with MoS2 growth. We found that by introducing H2 gas to the process, DES pyrolysis is significantly hindered, which reduces carbon incorporation. The C content in the MoS2 films is shown to quench the MoS2 photoluminescence and influence the trion-To-exciton ratio via charge transfer. This finding is fundamental for understanding process-induced C impurity doping in MOCVD-grown 2D semiconductors and might have important implications for the functionality and performance of (opto)electronic devices., This work was funded by the European Union’s Horizon 2020 research and innovation programme (BrainCom, grant no. 732032, Nanosmart, grant no. 825430 and Graphene Flagship Core 3, grant no. 881603). We also acknowledge funding from Generalitat de Catalunya (2017 SGR 1426), and the 2DTecBio (FIS2017-85787-R) funded by the Spanish Ministry of Science, Innovation and Universities, the Spanish Research Agency (AEI), and the European Regional Development Fund (FEDER/UE). The ICN2 is funded by the CERCA programme/Generalitat de Catalunya and supported by the Severo Ochoa Centres of Excellence programme, funded by the Spanish Research Agency (AEI, grant no. SEV-2017-0706). C.M.S. acknowledges that this work has been done within the framework of the Ph.D. program in Materials Science of the Autonomous University of Barcelona. Furthermore, C.M.S. wants to thank Anh Tuan Hoang for fruitful discussions.

This paper reports the synthesis, structural characteristics and magnetism of SrFe12O19/MCe0.04Fe1.96O4 (M = Cu, Ni, Mn, Co and Zn) hard/soft nanocomposites. The hard/soft compositions were manufactured via a one-pot reactions citrate sol-gel approach. The hard/soft phases formation was confirmed using XRD, SEM, TEM and HRTEM techniques. M vs. H (Magnetization measurements) were done at unbent temperature and 10 K. Smoothed M against H loops and single peaks in dM/dH vs. H curves were noticed in SrFe12O19/MnCe0.04Fe1.96O4, SrFe12O19/CuCe0.04Fe1.96O4 and SrFe12O19/ZnCe0.04Fe1.96O4 hard/soft nanocomposites. This indicated the manifestation of well exchange-coupled effect among hard and soft phases in these composites. However, SrFe12O19/CoCe0.04Fe1.96O4 and SrFe12O19/NiCe0.04Fe1.96O4 hard/soft nanocomposites showed non-well smoothed M against H loops and two peaks in dM/dH versus H plots, indicating that the dipolar interactions are unimportant compared to exchange-coupling behavior. Among all prepared nanocomposites, the SrFe12O19/MnCe0.04Fe1.96O4 hard/soft nanocomposite showed the highest exchange-coupling behavior. Microwave properties of the SrFe12O19/MCe0.04Fe1.96O4 (M = Cu, Ni, Mn, Co and Zn) hard/soft nanocomposites were investigated using coaxial method with applied frequency values fall between 2 and 18 GHz. Reflection losses were calculated from frequency dependences of the imaginary and real parts of permeability and permittivity. The correlation between the chemical composition of the spinel phase (A-cation) and microwave properties of composites. Most intensive electromagnetic absorption was observed for Ni- and Mn-spinels. This is can be a result of the differences in electron shell configuration and radii for A-site ions in the spinel phase. Change of the absorption mechanisms (transition from ionic polarization to dipole polarization) was observed. © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). The work was supported by the Russian Science Foundation (agreement number 19-72-10071 ). Also Authors are thank to the Institute for Research & Medical Consultations (Projects Application No. 2018-IRMC-S-2 ) of Imam Abdulrahman Bin Faisal University (IAU – Saudi Arabia) for financial and technical supports.

Herein, we investigated the correlation between the chemical composition, microstructure, and microwave properties of composites based on lightly Tb/Tm-doped Sr-hexaferrites (SrTb0.01Tm0.01Fe11.98O19) and spinel ferrites (AFe2O4, A = Co, Ni, Zn, Cu, or Mn), which were fabricated by a one-pot citrate sol-gel method. Powder XRD patterns of products confirmed the presence of pure hexaferrite and spinel phases. Microstructural analysis was performed based on SEM images. The average grain size for each phase in the prepared composites was calculated. Comprehensive investigations of dielectric properties (real (ε′) and imaginary parts (ε′′) of permittivity, dielectric loss tangent (tan(δ)), and AC conductivity) were performed in the 1-3 × 106Hz frequency range at 20-120 °C. Frequency dependency of microwave properties were investigated using the coaxial method in frequency range of 2-18 GHz. The non-linear behavior of the main microwave properties with a change in composition may be due to the influence of the soft magnetic phase. It was found that Mn- and Ni-spinel ferrites achieved the strongest electromagnetic absorption. This may be due to differences in the structures of the electron shell and the radii of the A-site ions in the spinel phase. It was discovered that the ionic polarization transformed into the dipole polarization. © The Royal Society of Chemistry 2020. 2020-164-IRMC 2018-IRMC-S-2 Ministry of Science and Higher Education of the Russian Federation The authors highly acknowledged the nancial supports provided by the Institute for Research and Medical Consultations (Project application No. 2018-IRMC-S-2) and by the Deanship for Scientic Research (Project application No. 2020-164-IRMC) of Imam Abdulrahman Bin Faisal University (Saudi Arabia). M. S. acknowledges the Ministry of Science and Higher Education of the Russian Federation State assignment 2020– 2022 No. FSMR-2020-0018 (Proposal mnemonic code 0719-2020-0018). The work was partially supported by Act 211 Government of the Russian Federation, contract No. 02.A03.21.0011.

Melt transport mechanisms have an important impact on the chemical composition of the percolated host rock and the migrating melts. Melt migration is usually assumed to occur at grain boundaries. However, microstructural studies revealed the occurrence of polyphase inclusions along dislocations, subgrain boundaries and microcracks in single mineral grains. The inclusions are interpreted as crystallized melt pockets suggesting that melts can migrate within deformed crystals. Intracrystalline melt migration and diffusive re-equilibration can lead to significant mineral trace element enrichments when associated with dissolution–precipitation reactions. In this contribution, we study a body of replacive troctolites associated with the Erro-Tobbio ophiolitic mantle peridotites (Ligurian Alps, Italy). The replacive formation of the olivine-rich troctolite involved extensive impregnation of a dunitic matrix, i.e. partial dissolution of olivine and concomitant crystallization of interstitial phases. The olivine matrix is characterized by two distinct olivine textures: (i) coarse deformed olivine, representing relicts of the pre-existing mantle dunite matrix (olivine1), and (ii) fine-grained undeformed olivine, a product of the melt–rock interaction process (olivine2). Previous studies documented a decoupling between olivine texture and trace element composition, namely enriched trace element compositions in olivine1 rather than in olivine2, as would be expected from the dissolution–precipitation process. Notably, the trace element enrichments in deformed olivines are correlated with the occurrence of elongated 10 µm size polyphase inclusions (clinopyroxene, Ti-pargasite, chromite) preferentially oriented along olivine crystallographic axes. These inclusions show irregular contacts and have no crystallographic preferred orientation with the host olivine, and the phases composing the inclusions show similar chemical compositions to the vermicular phases formed at the grain boundaries during late-stage reactive crystallization of the troctolite. This suggests that the investigated inclusions did not form as exsolutions of the host olivine but rather by input of metasomatic fluids percolating through the deformed olivine grains during closure of the magmatic system. We infer that strongly fractionated volatile-rich melts were incorporated in oriented microfractures within olivine1 and led to the crystallization of the polyphase inclusions. The presence of intracrystalline melt greatly enhanced diffusive re-equilibration between the evolved melt and the percolated olivine1, in turn acquiring the enriched character expected in neoformed olivine crystals. Intracrystalline melt percolation can have strong geochemical implications and can lead to efficient re-equilibration of percolated minerals and rocks.

The present work deals with adjusting a fine-grained microstructure in iron-rich iron-aluminium alloys using the ECAP-process (Equal Channel Angular Pressing). Due to the limited formability of Fe-Al alloys with increased aluminium content, high forming temperatures and low forming speeds are required. Therefore, tool temperatures above 1100 &deg, C are permanently needed to prevent cooling of the work pieces, which makes the design of the ECAP-process challenging. For the investigation, the Fe-Al work pieces were heated to the respective hot forming temperature in a chamber furnace and then formed in the ECAP tool at a constant punch speed of 5 mm/s. Besides the chemical composition (Fe9Al, Fe28Al and Fe38Al (at.%&mdash, Al)), the influences of a subsequent heat treatment and the holding time on the microstructure development were investigated. For this purpose, the average grain size of the microstructure was measured using the AGI (Average Grain Intercept) method and correlated with the aforementioned parameters. The results show that no significant grain refinement could be achieved with the parameters used, which is largely due to the high forming temperature significantly promoting grain growth. The holding times in the examined area do not have any influence on the grain refinement.

Avoiding low austenite fractions and nitride formation are major challenges in laser welding of duplex stainless steels (DSS). The present research aims at investigating efficient means of promoting austenite formation during autogenous laser welding of DSS without sacrificing productivity. In this study, effects of shielding gas and laser reheating were investigated in welding of 1.5-mm-thick FDX 27 (UNS S82031) DSS. Four conditions were investigated: Ar-shielded welding, N2-shielded welding, Ar-shielded welding followed by Ar-shielded laser reheating, and N2-shielded welding followed by N2-shielded laser reheating. Optical microscopy, thermodynamic calculations, and Gleeble heat treatment were performed to study the evolution of microstructure and chemical composition. The austenite fraction was 22% for Ar-shielded and 39% for N2-shielded as-welded conditions. Interestingly, laser reheating did not significantly affect the austenite fraction for Ar shielding, while the austenite fraction increased to 57% for N2-shielding. The amount of nitrides was lower in N2-shielded samples compared to in Ar-shielded samples. The same trends were also observed in the heat-affected zone. The nitrogen content of weld metals, evaluated from calculated equilibrium phase diagrams and austenite fractions after Gleeble equilibrating heat treatments at 1100 °C, was 0.16% for N2-shielded and 0.11% for Ar-shielded welds, confirming the importance of nitrogen for promoting the austenite formation during welding and especially reheating. Finally, it is recommended that combining welding with pure nitrogen as shielding gas and a laser reheating pass can significantly improve austenite formation and reduce nitride formation in DSS laser welds.

Phonon surface scattering has been at the core of heat transport engineering in nanoscale devices. Herein, we demonstrate that this phonon pathway can be the sole mechanism only below a critical, size-dependent temperature. Above this temperature, the lattice phonon scattering coexists along with surface effects. By tailoring the mass disorder at the atomic level, the lattice dynamics in nanowires was artificially controlled without affecting morphology, crystallinity, chemical composition, or electronic properties, thus allowing the mapping of the temperature-thermal conductivity-diameter triple parameter space. This led to the identification of the critical temperature below which the effects of lattice mass disorder are suppressed to an extent that phonon transport becomes governed entirely by the surface. This behavior is discussed based on a modified Landauer-Datta-Lundstrom near-equilibrium transport model. Besides disentangling the main phonon scattering mechanisms, the established framework also provides the necessary input to further advance the design and modeling of heat transport in semiconductor nanoscale systems., ICN2 acknowledges funding from Generalitat de Catalunya 2017 SGR 327. ICN2 is supported by the Severo Ochoa program from Spanish MINECO (Grant No. SEV-2017-0706) and is funded by the CERCA Programme/Generalitat de Catalunya.

Graphene is a one-atom-thick sheet of carbon atoms arranged in a honeycomb pattern and its unique and amazing properties make it suitable for a wide range of applications ranging from electronic devices to food packaging. However, the biocompatibility of graphene is dependent on the complex interplay of its several physical and chemical properties. The main aim of the present study is to highlight the importance of integrating different characterization techniques to describe the potential release of airborne graphene flakes in a graphene processing and production research laboratory. Specifically, the production and processing (i.e., drying) of few-layer graphene (FLG) through liquid-phase exfoliation of graphite are analysed by integrated characterization techniques. For this purpose, the exposure measurement strategy was based on the multi-metric tiered approach proposed by the Organization for Economic Cooperation and Development (OECD) via integrating high-frequency real-time measurements and personal sampling. Particle number concentration, average diameter and lung deposition surface area time series acquired in the worker's personal breathing zone (PBZ) were compared simultaneously to background measurements, showing the potential release of FLG. Then, electron microscopy techniques and Raman spectroscopy were applied to characterize particles collected by personal inertial impactors to investigate the morphology, chemical composition and crystal structure of rare airborne graphene flakes. The gathered information provides a valuable basis for improving risk management strategies in research and industrial laboratories.

Located in the East Kunlun Orogen, China, the Xiarihamu magmatic nickel–cobalt sulfide deposit is the country’s second largest deposit of this type. It was formed in special early Paleozoic with low copper grade (0.14 wt%) compared with other deposits of the same type. The mineralogy of nickel and cobalt minerals, which are direct carriers of these elements, can clearly reflect their behavior in the process of mineralization; however, such information for this deposit remains unreported. In the present study, we use an electron microscope and electron probe microanalyzer to delineate and analyze many nickel and cobalt minerals such as maucherite, nickeline, cobaltite, violarite, gersdorffite, parkerite, and arsenohauchecornite in various rocks and ores. With the increase in crustal material contamination, it can reach arsenide saturation locally in sulfide melt, then a separate Ni-rich arsenide (bismuth) melt exsolves somewhere. This melt will crystallize into nickeline, parkerite, arsenohauchecornite, and maucherite first. Second, most of nickel and cobalt tend to enter cobaltite and pentlandite phases, rather than existing in chalcopyrite and pyrrhotite phases as isomorphism during sufficient fractional crystallization of sulfide melt, which gathered nickel and cobalt elements widely. Also, more than one magma might result in the superposition of ore-forming elements. Later, the ore-forming elements redistribute limitedly through a hydrothermal process. The metallogenic mechanism model of nickel and cobalt established in the present study not only explains the process of nickel–cobalt mineralization in Xiarihamu but also can be applied to similar deposits and has a wide universal replicability.

Understanding neural physiopathology requires advances in nanotechnology-based interfaces, engineered to monitor the functional state of mammalian nervous cells. Such interfaces typically contain nanometer-size features for stimulation and recording as in cell-non-invasive extracellular microelectrode arrays. In such devices, it turns crucial to understand specific interactions of neural cells with physicochemical features of electrodes, which could be designed to optimize performance. Herein, versatile flexible nanostructured electrodes covered by arrays of metallic nanowires are fabricated and used to investigate the role of chemical composition and nanotopography on rat brain cells in vitro. By using Au and Ni as exemplary materials, nanostructure and chemical composition are demonstrated to play major roles in the interaction of neural cells with electrodes. Nanostructured devices are interfaced to rat embryonic cortical cells and postnatal hippocampal neurons forming synaptic circuits. It is shown that Au-based electrodes behave similarly to controls. Contrarily, Ni-based nanostructured electrodes increase cell survival, boost neuronal differentiation, and reduce glial cells with respect to flat counterparts. Nonetheless, Au-based electrodes perform superiorly compared to Ni-based ones. Under electrical stimulation, Au-based nanostructured substrates evoke intracellular calcium dynamics compatible with neural networks activation. These studies highlight the opportunity for these electrodes to excite a silent neural network by direct neuronal membranes depolarization.

A radio frequency magnetron co-sputtering technique exploiting GaTe and S b 2 T e 3 targets was used for the fabrication of Ga–Sb–Te thin films. Prepared layers cover broad region of chemical composition ( ∼ 10.0 − 26.3 a t . % of Ga, ∼ 19.9 − 34.4 a t . % of Sb) while keeping Te content fairly constant (53.8–55.6 at. % of Te). Upon crystallization induced by annealing, large variations in electrical contrast were found, reaching a sheet resistance ratio of R a n n e a l e d / R a s − d e p o s i t e d ∼ 2.2 × 10 − 8 for the G a 26.3 S b 19.9 T e 53.8 layer. Phase transition from the amorphous to crystalline state further leads to huge changes of optical functions demonstrated by optical contrast values up to | Δ n | + | Δ k | = 4.20 for G a 26.3 S b 19.9 T e 53.8 composition.

In this study, the material strength of a carbon steel (JIS SS400), which has been used for the penstock of a hydroelectric power plant for about 50 years, is examined. A series of data were obtained and analyzed by measuring the chemical compositions, observing the macro- and micro-structure and conducting tensile tests. The present study revealed that the material strength (0.2% proof strength and ultimate tensile strength) measured at one site can not be regarded as a reliable representative of the entire structure. On the other hand, strong and positive correlation between equivalent carbon content and material strength indicates that measuring the former is an effective and reasonably accurate estimate of the latter. In addition, potential use of nondestructive evaluations, including the Vickers hardness, and their reliability is discussed. In practice, a series of statistical analysis with those valuable field data provides us with the insight on the material strength of long-term used penstock.

The experimental study on the electrical conductivities of schists with various contents of alkali ions (CA = K2O + Na2O = 3.94, 5.17, and 5.78 wt.%) were performed at high temperatures (623&ndash, 1073 K) and high pressures (0.5&ndash, 2.5 GPa). Experimental results indicated that the conductivities of schist markedly increased with the rise of temperature. Pressure influence on the conductivities of schist was extremely weak at the entire range of experimental temperatures. Alkali ion content has a significant influence on the conductivities of the schist samples in a lower temperature range (623&ndash, 773 K), and the influence gradually decreases with increasing temperature in a higher temperature range (823&ndash, 1073 K). In addition, the activation enthalpies for the conductivities of three schist samples were fitted as being 44.16&ndash, 61.44 kJ/mol. Based on the activation enthalpies and previous studies, impurity alkaline ions (K+ and Na+) were proposed as the charge carriers of schist. Furthermore, electrical conductivities of schist (10&minus, 3.5&ndash, 10&minus, 1.5 S/m) were lower than those of high-conductivity layers under the Tibetan Plateau (10&minus, 1&ndash, 100 S/m). It was implied that the presence of schist cannot cause the high-conductivity anomalies in the middle to lower crust beneath the Tibetan Plateau.

WOS: 000475998500046, In this work, precipitation and sol-gel mixed procedures were used to prepare a TiO2@Fe3O4 nanocomposite. The X-ray diffraction (XRD) and selected area electron diffraction (SAED) results unmistakably elucidated the tetragonal structure of TiO2 with the cubic structure of Fe3O4 . The particle size, interface, and surface area were determined by transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) measurements. The TEM image of the prepared TiO2@Fe3O4 clearly showed that the material is nano-spherical in shape. The BET surface area of the nanocomposite was measured to have a higher value (115.7 m(2)/g) than those of the TiO2 (65.2 m/g) and Fe3O4 (30.1 m(2)/g) pure systems because of the synergistic effect and interface between the two different oxides. The absorption edges of the TiO2@Fe3O4 nanocomposites were studied with the UV-abs spectrometer, and the results revealed that the material band gap is 2.70 eV. The chemical composition and dispersion of the nanocomposite system was assessed via energy dispersive X-ray spectroscopy (EDS) along with elemental mapping. The PL spectra of the prepared nanocomposite system indicated a delay of the electron-hole recombination process due to the presence of Fe3O4, thus inducing intermediate states into the TiO2 system. The favourable optical properties of the developed nanocomposites were exploited for the photocatalytic degradation of colourful dyes, such as methylene blue, and methyl orange, as well as of colourless phenol. In addition, their stability and photocatalytic mechanism are explained in detail. (C) 2019 Published by Elsevier B.V., FONDECYT Government of ChileComision Nacional de Investigacion Cientifica y Tecnologica (CONICYT)CONICYT FONDECYT [11170414], We acknowledge Dr. K. Ravichandran, Department of Nuclear Physics, University of Madras, India for the lab facilities and his valuable contribution for the discussion. The author (S.R) acknowledge FONDECYT Government of Chile (Project No.: 11170414), for the support to carry out this project

This paper presents a brief review of the systematic study of the influence of the chemical composition on the structure, phase transformations and physical properties of binary and quasi-binary Ti-Ni, TiNi-TiFe, TiNi-NiCu, NiMn-NiGa and Ni2MnGa-Ni3Ga systems, which undergo thermoelastic martensitic transformations (TMT) and related with them thermally, mechanically, or magnetically controlled shape memory effects (SME). The effect of alloying with a third component on the behavior of critical temperatures and the TMT sequence has been established, and their generalized diagrams have been constructed. It is shown that the morphology of thermoelastic martensite is a hierarchy of packets of thin coherent crystals. © Published under licence by IOP Publishing Ltd. Russian Foundation for Basic Research, RFBR: 18-32-00529 mol_а Ural Branch, Russian Academy of Sciences, UB RAS: 18-10-2-39 Federal Agency for Scientific Organizations: АААА-А18-118020190116-6 This work was performed within the state task of Federal Agency for Scientific Organizations (theme Struktura, no. АААА-А18-118020190116-6), with the support of the Project UB RAS (no. 18-10-2-39) and was partly supported by the Russian Foundation for Basic Research (project no. 18-32-00529 mol_а).

Design of materials for solid oxide fuel cells cathodes and oxygen separation membranes and studying their oxygen transport characteristics are important problems of modern hydrogen energy. In the current work, fundamentals of such materials design based on characterization of their oxygen mobility by oxygen isotope exchange with C18O2 and 18O2 in flow and closed reactors for samples of Ruddlesden - Popper-type oxides Ln2-xCaxNiO4+δ, perovskite-fluorite nanocomposites PrNi0.5Co0.5O3-δ - Ce0.9Y0.1O2-δ, etc. are presented. Fast oxygen transport was demonstrated for PNC - YDC (DO ~10-8 cm2/s at 700°C) nanocomposites due to domination of the fast diffusion channel involving oxygen of the fluorite phase with incorporated Pr cations and developed perovskite-fluorite interfaces. For LnCNO materials a high oxygen mobility (DO ~10-7 cm2/s at 700°C) provided by the cooperative mechanism of its migration was demonstrated. Depending on Ca dopant content and Ln cation nature, in some cases 1-2 additional channels of the slow diffusion appear due to decreasing the interstitial oxygen content and increasing the energy barrier for oxygen jumps due to cationic size effect. Optimized by the chemical composition and nanodomain structure materials of these types demonstrated a high performance as SOFC cathodes and functional layers in asymmetric supported oxygen separation membranes. © The Authors, published by EDP Sciences, 2019. Russian Science Foundation, RSF: 16-13-00112 Support by the Russian Science Foundation (Project 16-13-00112) is gratefully acknowledged. The authors from the Ural Federal University are grateful to the Government of the Russian Federation (Agreement 02.A03.21.0006, Act 211). Ce0.9Y0.1O2-δ|Ce0.9Gd0.1O2-δ|Ni/Zr0.84Y0.16O2-δ anodic half-cells and Ni/Al foam substrates were kindly provided by H.C. Starck, Germany and Powder Metallurgy Institute NAN Belarus, respectively.

The study investigated 16 grades of austenitic stainless steels (ASS) with different chemical composition, including nitrogen. Metallographic and electrochemical studies of pitting corrosion in a solution of 3.5% NaCl (GOST 9.912) were carried out. The optimum ratios of carbon and nitrogen concentrations in ASS are determined, which allow obtaining high resistance to pitting corrosion and high strength. Equation of the dependence of break down potential Eb and strength (Rp0.2 and Rm) on the chemical composition of the steels with nitrogen were proposed. The effect of heat treatment and severe plastic deformation on the pitting resistance, mechanical and paramagnetic properties of the HNS has been studied. It was shown that during SPD, the HNS strength increased by about 3 times, while the fracture was not brittle and occurred by the quasi-cleavage mechanism. Although the potential of Eb decreased, it remained higher than that of steel 09Cr18Ni10Ti. The HNS of the investigated composition also showed high resistance to stress corrosion cracking in a quenched and aged at 500 zC states, and did not show embrittlement in a corrosive environment even after SPD.

Compounds with a tetragonal structure of the ThMn12 type have a high potential for creating on their basis permanent magnets with high energy density and operating temperatures up to 150 – 200 °C. In this work, samples of alloys (Sm1-x Zr x )Fe11Ti (x = 0 – 0.2) obtained by the rapidly quenching method with subsequent annealing were investigated. Depending on the chemical composition and modes of synthesis in alloys (Sm1-x Zr x )Fe11Ti (x = 0 – 0.2) phases of the ThMn12, α-Fe type and a small amount of ZrFe2 are formed, as well as phases with the Th2Zn17 structural type and TbCu7 at high annealing temperatures. The best magnetic properties at room temperature are realized in the alloy (Sm0.9Zr0.1)Fe11Ti after annealing at a temperature of 800 °C.

This paper describes a versatile in situ etching-growth strategy for the preparation of periodic mesoporous organosilica (PMO) composites with yolk-shell structure, which can generate the void space and construct the outer PMO shells at the same time. The superparamagnetic yolk-shell Fe3O4@PMO composites (YS-Fe3O4@PMO) with radical mesochannels were also synthesized with this unique in situ etching-growth strategy by using Fe3O4@nSiO2 nanoparticles as the initial core. This method provides a general route for the synthesis of yolk-shell structured nanomaterials with different sized void spaces, various chemical composition cores, as well as organic functional PMO shells with radical mesochannels. Moreover, we can also obtain asymmetric or asymmetric hollow Fe3O4@PMO materials with a cubic PMO shell. All the magnetic mesoporous composites possess very high surface areas and large pore volumes (586 m2 g-1 and 0.52 cm3 g-1 for YS-Fe3O4@PMO, 946 m2 g-1 and 0.86 cm3 g-1 for asymmetric hollow Fe3O4@PMO). Gold nanoparticles could be encapsulated and confined in the void space of YS-Fe3O4@PMO composites through an in situ salt impregnation. The resultant YS-Fe3O4@Au@PMO nanomaterials could be used to catalyze the reduction of 4-nitrophenol with an ultrahigh efficiency (k = 0.01197 s-1). The magnetic catalysts could be easily recovered by a magnet and reused for more than 10 cycles with efficiency retained as high as 95%. 2016 The Royal Society of Chemistry. This work was supported by the State Key Basic Research Program of the PRC (2012CB224805, 2013CB934104), the NSF of China (21210004 and U1463206), Shanghai Sci. & Tech. Committee (14JC1400700). We extended our appreciation to the Deanship of Scientific Research at King Saud University for funding the work through the 530 research group Project No. RGP-227. Scopus

cited By 1; International audience; The susceptibility of Ni-Cr alloys to pitting corrosion is known to be closely related to the Cr content in the alloy. However, the role of Cr in the different stages of the pitting process is not totally understood. To determine the role Cr in the different stages of the pitting process, the passive films formed on different nickel-base alloys (with 16, 20, 24 and 28 wt% Cr) in a sulfate solution were characterized using electrochemical techniques and X-ray photoelectron spectroscopy. Electrochemical impedance spectroscopy (EIS) analyses are discussed in terms of the migration of point defects. Metastable and stable pitting was then studied using polarization curves in a 0.1 M NaCl solution. The alloys studied exhibit a wide range of susceptibility. The 16 wt% Cr alloy was the most susceptible to metastable and stable pitting while the 28 wt% Cr alloy was almost unaffected by both phenomena. By studying the chemical composition of the passive film, it was shown that nickel incorporated into the passive film was responsible for deleterious interactions between the surface and chloride ions leading to metastable pit events. Migration resistance is a good indicator of the passivity breakdown process based on the EIS results. Low migration resistance values imply the presence of a vacancy condensation process while high values imply a thinning process. As a result, a step by step mechanism is proposed showing chloride ion interaction with passive films at stable pit initiation. © 2016 The Electrochemical Society.

We measured the elemental chemical composition of architectural float glass fragments using inductively coupled mass spectrometry with a laser ablation add-in. Measurements of 18 elemental concentrations were obtained from each fragment at each measurement occasion. These data can be used for statistical analysis with the purpose of evaluating forensic trace evidence. The data collection and measurement process in this database were carefully designed by the authors to enable understanding similarities and differences in elemental composition within a fragment, between fragments within a pane, between panes produced by the same manufacturer, and between manufacturers, to help in forensic glass evaluation. We received 48 panes that were produced on consecutive days, from two glass manufacturers in the U.S. Half of each pane was broken into small fragments and 24 fragments were randomly sampled from each half pane. To compute well-conditioned estimates of high-dimensional covariance matrices at all levels, we replicated measurements on each fragment; for three of the 24 fragments from a pane, we obtained 20 replicate measurements, and for the other 21 fragments, we made five replicate measurements. Analytical procedures to carry out the measurements followed the protocols recommended for forensic float glass samples by ENFSI [1] and the ASTM [2]. The database described in this article is related to two published research articles, "Learning algorithms to evaluate forensic glass evidence" by Park and Carriquiry (2019) [3] and "Evaluation and comparison of methods for forensic glass source conclusions" by Park and Tyner (2019) [4].

The preparation of multicomponent coatings based on silicon and yttrium on the niobium substrate was investigated. Y-Si/NbSi2 coatings on the Nb substrate by currentless deposition in molten salts were produced. The preparation of NbSi2 layers is carried out in NaF-NaCl-Na2SiF6 melts with the addition of Si powder. The preparation of Y-Si layers is carried out in NaCl-KCl-YF3 melts containing Y powder. Coating samples are studied using SEM. It is established that sequentially synthesized coatings are characterized by a two-layer structure. Using the EDS method, the chemical composition of the obtained layers is established: Y - 26.68; Nb - 62.55; Si - 10.76 wt. %. The oxidation test of the obtained coatings Y-Si/NbSi2 on Nb samples is performed. It is found that testing at 1200 oC for 2 hours leads to a mass loss of 62 mg/cm2•h. © Published under licence by IOP Publishing Ltd. Ministry of Education and Science of the Russian Federation, Minobrnauka: 14.578.21.0238, RFMEFI57817X0238 The study was carried out with financial support of the Ministry of Education and Science of the Russian Federation within the frames of the Federal target program, the agreement number 14.578.21.0238, identification number RFMEFI57817X0238.

The quality of steel rods used in structural applications has been subjected to continuous scrutiny by researchers in Nigeria. In this data article, the experimental data on the chemical and mechanical properties of steel rods from collapsed building sites and local steel plants have been reported. The chemical composition consisting of carbon, manganese, silicon, sulphur, phosphorus among other elements were recorded using an optical emission spectrometer. Some of the main elements were used to evaluate the carbon equivalent value and the results are reported in this article. The yield strength, ultimate tensile strength and percentage elongation were also presented as obtained from the universal testing machine. The hardness values of the steel rod samples were also presented. Keywords: Mechanical properties, Collapsed building, Steel rods, Chemical compositions, Percentage elongation

We worked out a spectral oil analyzer, implemented the method of Fourier transform infrared spectroscopy, which allow simultaneous detecting characteristic peaks of water absorption and sulfur-containing substances in oil within the wavelength range from 0.2 to 25.0 μm. The usage of fiber-optic delivering channels makes it possible to produce online industrial probes for the control of chemical composition and concentration, what is demanded at oil producing platforms and oil refinery plants. As identifiers, we used the most intense absorption peaks of water (λ - 1.45 μm, 1.95 μm, 3.00 μm, 6.00 μm), oil (λ - 1.72 μm, 2.31 μm, 3.41 μm) and sulfur-containing heterocycles (λ - 8.00 μm). The spectral analyzer consists of a broadband-light source, a flow-cell, a fiber-optic assembly, narrow-band optical filters and photodetectors. For delivering a broadband optical signal, a fiber-optic assembly was developed. It comprises silica fibers and polycrystalline fibers derived from solid solutions of silver and thallium (I) halides. It was calculated the effective area and diameter of each fiber type in the assembly, taking into account attenuation coefficients and overall optical losses of the system. Using eight channels for the probe at the same time, we were able to measure the content of water and sulfur-containing substances in oil in concentrations from 0.1 to 100.0 wt %. © Published under licence by IOP Publishing Ltd. Russian Science Foundation, RSF: 18-73-10063 This work was supported by the Russian Science Foundation under grant No. 18-73-10063.

"Available online 21 November 2017", The deposition of decorative coatings is an excellent solution to modify the surface of any material, particularly the aesthetic finishing, without altering the properties of the substrate. Transition metal oxynitride films are interesting for many applications, due the simple and economic way to tune between nitride and oxide bonding. In reactive sputtering, this is done by playing with the flows of N2 and O2, leading to variations of properties (e.g. color) in different directions. In this paper, zirconium is selected as transition metal due to combination of different characteristics (color, biocompatibility, mechanical properties, corrosion resistance). The literature about Zr-O-N films reveals a confinement of chemical composition. Therefore, the aim of this work is the exploration of the deposition parameter space in order to evaluate the stability of the Zr-O-N system, i.e. verify if the chemical composition of the films still falls in the same range after variation of different deposition parameters. To do that, a series of Zr-O-N films is deposited first at different reactive flows, maintaining the remaining deposition parameters constant. The obtained films can be classified in three different groups, based on their chemical composition, crystalline structure, and film growth. These groups can be successfully explained according to the sputtering characteristics, and correlated with the mechanical properties and color of the films measured by nanoindentation and spectrophotometry receptivity. The films deposited by variation of other parameters are introduced afterwards and their characteristics are compared with the reference series., The financial support of Portuguese Foundation of Science and Technology (FCT), under the project number IF/00671/2013 is gratefully acknowledged., info:eu-repo/semantics/acceptedVersion

Pulp yield can be improved by a more homogeneous delignification of the chips, achieved by improved impregnation prior to the cooking stage. Complete and efficient impregnation is obtained by increasing the diffusion rate by means of an impregnation liquor with a high initial effective alkali concentration (HIEAC). In the present study, the effect of HIEAC in the impregnation was evaluated and compared to a reference impregnation procedure and a prolonged impregnation. After the various impregnation scenarios, the alkali concentration was always adjusted to the same level in the beginning of the cooking stage. Impregnation with a HIEAC resulted in yield improvements by 1–1.5% units, due to a higher cellulose yield and possibly also to higher yield of glucomannan. The HIEAC with an even alkali distribution within the chips prior to the cooking stage resulted in a more uniform delignification carbohydrate degradation. Yield increase obtained by uniform delignification is due to both decreased shives content as well as less secondary peeling.

The casting processes are characterized by complex relationships between predictors and responses. It is the fundamental understanding of these complex relationships that often involves hundreds of factors, which improves quality without losing productivity and raising cost. In this work, cast solid solution strengthened ferritic spheroidal graphite irons GJS-500-14 and GJS-600-10 (EN 1563:2012) have been evaluated. These materials offer stronger components with good machinability owing to their even hardness properties. In this case the predictors are chemical composition, gating layout, foundry set-up, testing procedure and equipment etc. and the responses are the tensile properties (Rp0.2, Rm, A5). Here 200 tensile specimens compiled from industrial foundry melts from over 30 years of research have created a state-of-the-art platform for statistical engineering in order to perform Exploratory Data Analysis (EDA) and data visualization. This statistical platform has provided new insight on how foundries should treat complex relationships between predictors and responses in order to identify sources of variation and interaction effects.

The present study primarily focuses on lamination in beta-phase of Ti-5553 titanium alloy. Microstructure and chemical composition of Ti-5553 alloy after heat-treatment was investigated by electron microscopy (SEM, TEM), x-ray diffraction (XRD) and energy dispersive x-ray analysis (EDX). It was revealed that after annealing and slow cooling from β phase field the β phase separated into β-enriched and β-lean regions. This effect does not effect on precipitation of secondary α phase. © Published under licence by IOP Publishing Ltd. This article was prepared with the financial support of Ural Federal University Competitiveness Enhancement Program – CEP 3.1.1.1-18. BVD PECE spol. s r.o.;CSNMT;DynaWeld;EDAX;et al.;Linseis

For the realization of liquid lubricant free forming processes different approaches are conceivable. The priority program 1676 “Dry forming - Sustainable production through dry machining in metal forming” addresses this issue in the context of metal forming processes. The present study reports results from one subproject of the priority program that employs selective oxidization of tool steel surfaces for the implementation of a dry sheet metal deep drawing process. Within the present study, specimen surfaces of the tool steel (1.2379) were heat-treated to optimize their tribological properties with respect to sliding wear behaviour in contact with drawn sheet metal (DP600+Z). The heat treatment was designed to result in the formation of selective oxide layers that can act as friction reducing separation layers. The heating setup employed an inductive heating under protective gas atmosphere. Selective oxidation was realized by controlling the residual oxygen content. Specifically, the specimens were heated in the near-surface region just above the annealing temperature, thus avoiding the degradation of mechanical properties in the bulk. Evaluation of hardness along cross-sections of each specimen revealed suitable initial temperatures for the inductive heat treatment. Oxide layer systems were analyzed regarding their tribological sliding wear behaviour after selective oxidation, as well as their morphology and chemical composition before and after the sliding wear tests.

Corrosion behavior of wrought Stellite 6B and Stellite 6K, which have similar chemical composition but contain different carbon content, in 3.5 wt.% NaCl solution and in Green Death solution is investigated using various electrochemical methods, including potentiodynamic polarization, cyclic polarization, and electrochemical impedance spectroscopy (EIS). The obtained potentiodynamic polarization curves, cyclic polarization curves, and EIS spectra for these alloys are in good agreement, showing that Stellite 6K with higher carbon content is easier corroded due to its larger volume fraction of carbides but the Cr2O3 film formed on this alloy is stronger and more stable than that on Stellite 6B. Further immersion tests on these alloys show that Stellite 6K has less resistance to pitting corrosion.

Layered double hydroxides (LDHs) are an ultravioletlight (UV)-resistant material. In this study, two types of LDHs (Mg-Al-LDHs and Zn-Al-LDHs) were applied to modify bitumen by melt-blending. The effect of ultraviolet aging on the rheology and chemistry of LDH-modified bitumen was studied by means of dynamic shear rheometer (DSR), thin-layer chromatography with flame ionization detection (TLC-FID), Fourier transform infrared spectroscopy (FTIR), and Ultraviolet-Visible (UV-Vis) spectrophotometry to reveal the mechanisms of action for LDHs and bitumen. The results showed that within the UV spectra (220–400 nm), the reflectance of Zn-Al-LDHs was larger than that of Mg-Al-LDHs. These two LDHs have different influences on the performance of bitumen. Mg-Al-LDHs had a more obvious influence on the physical and dynamic rheological properties of bitumen than Zn-Al-LDHs. Zn-Al-LDHs improved the UV-aging resistance of bitumen more. The reason can be that the reflectance of the Zn-Al-LDHs to the UV light is larger than that of the Mg-Al-LDHs. The Zn-Al-LDH-modified bitumen had more potential to improve the UV-aging resistance during the service life of asphalt pavement.

cited By 11; International audience; Surface segregation designates the phenomenon of variation in chemical composition between the surface and the bulk of an alloy, which can have a beneficial or detrimental effect on its physical and chemical properties. This is even more pronounced in nanoalloys, i.e., alloy systems comprised of nanoparticles, with significant surface-to-volume ratios. In this case study we demonstrate the element-specific Cr segregation in Ni-rich NiCr alloy nanoparticles and nanogranular films grown by gas-phase synthesis methods. In situ annealing measurements (300-800 K), performed under vacuum using aberration-corrected environmental transmission electron microscopy (E-TEM), and vibrating sample magnetometry (VSM) revealed progressive Cr segregation with annealing temperature and subsequent complete transformation into core-satellite structures at 700 K. Simultaneously, atomistic computer simulations (molecular dynamics (MD) and Metropolis Monte Carlo (MMC)) elucidated the resultant structures, explaining the driving force behind segregation energetically. Most importantly, we emphasize the significant effects of Cr segregation on magnetic properties, namely, (i) the highly nonsaturated M-H loops (below the Néel temperature of antiferromagnetic Cr) with reduced coercivities and (ii) the uncompensated high Curie temperatures, TC, compared to the NiCr bulk, which approach bulk Ni values upon annealing. Both are clear evidence that the distribution of Cr in the nearest-neighbor shells of Ni atoms differs from that of the bulk NiCr alloy, reconfirming our structural findings.

We experimentally demonstrate the first polymer optical fiber Bragg grating inscribed with only one krypton fluoride laser pulse. The device has been recorded in a single-mode poly(methyl methacrylate) optical fiber, with a core doped with benzyl dimethyl ketal for photosensitivity enhancement. One laser pulse with a duration of 15 ns, which provide energy density of 974 mJ/cm2, is adequate to introduce a refractive index change of 0.74×10-4 in the fiber core. After the exposure, the reflectivity of the grating increases for a few minutes following a second order exponential saturation. The produced Bragg grating structure rejects 17.9 dB transmitted power, thus providing 98.4% reflectivity, which is well suited for sensing applications. In addition, we report the importance of the fiber thermal treatment before or after the inscription, showing its effects on the lifetime and quality of the grating structures. Optimizing the irradiation conditions and the material chemical composition, a higher refractive index change in the fiber core is feasible. This demonstration significantly improves the potential for commercial exploitation of the technology.

cited By 0; International audience; Oxide dispersion-strengthened ferritic stainless steels are foreseen as fuel cladding tube materials for the new generation of sodium fast nuclear reactors. Those materials, which exhibit remarkable creep properties at high temperature, are reinforced by a dense precipitation of nanometric oxides. This precipitation is obtained by mechanical alloying of a powder and subsequent consolidation. Before consolidation, to obtain a fully dense material, the powder is vacuumed to outgas trapped gases and species adsorbed at the surface of the powder particles. This operation is commonly done at moderate to high temperature to evacuate as much as possible volatile species. This paper focuses on the influence of outgassing conditions on some properties of the further consolidated materials. Chemical composition and microstructural characterization of different materials obtained from various outgassing cycles are compared. Finally, impact toughness of those materials is evaluated by using Charpy testing. This study shows a significant influence of the outgassing conditions on the mechanical properties of the consolidated material. However, microstructure and oxygen contents seem poorly impacted by the various outgassing conditions. © 2017, The Minerals, Metals & Materials Society and ASM International.

This work is an experimental study on the formation, characteristics and properties of electroless nickel phosphorous (Ni-P) coatings and electroless nickel alumina (Ni-P-Al2O3) coating with varying reducing agent concentration. The results obtained indicate that the deposition rate and surface roughness of both Ni-P coating and Ni-P-Al2O3 coatings are highly influenced by reducing agent (sodium hypophosphite). With increase in sodium hypophosphite Ni forms amorphous phase and as a result the micro hardness of the coating gets reduced. Heat treatment was carried out at 400 �C for 1 h after the coating, resulted in the formation of an intermetallic nickel phosphide (Ni3P) phase which improved the hardness of the Ni-P coating from 400 � 25 to 700 � 25 HV. A composite coating is formed due to the incorporation of nano alumina in the Ni-P coating leading to an increase in the hardness. The chemical composition of nickel gets reduced from 85.3 to 77.8 wt.% due to the presence of alumina which resists the deposition of Ni. The uniform distribution of alumina particles are observed using a scanning electron micrograph and confirmed by X-ray diffraction techniques. The specific wear rate of Ni-P-Al2O3 coated and post coating heat treated specimens was observed to be less when compared with that obtained in the case of conventional Ni-P coating. � 2014 Elsevier B.V. All rights reserved.

Cataloged from PDF version of article. The harmful effect of nickel ions released from conventional stainless steel implants has provided a high level of motivation for the further development of nickel-free stainless steels. In this paper, the microstructure of medical-grade nickel-free stainless steel powders, with the chemical composition of ASTM F2581, is studied during mechanical alloying and subsequent annealing. Rietveld X-ray diffraction and transmission electron microscopy evaluations reflect nanocrystallization, austenitization and amorphization of the powders due to mechanical activation. It is also realized that annealing of the as-milled powder can develop a single austenitic structure with nanometric crystallite sizes, implying a considerable inherent resistance to grain growth. This study demonstrates the merit of mechanical alloying and subsequent annealing in the development of nanostructured medical-grade stainless steels. (C) 2012 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved

Present-day three-way catalysts operate in contact with exhaust gases whose temperature is as high as >1000 C, so the problem of developing thermally stable catalytic compositions is still topical. A series of Al2O 3-Ce0.75Zr0.25O2 composites containing 0, 10, 25, and 50 wt % Al2O3 has been synthesized by direct precipitation. The as-prepared composites and those calcined in air at 1000 and 1100 C have been characterized by BET, X-ray diffraction, transmission electron microscopy, and temperature-programmed reduction methods. The composites aged at 1050 C in a 2% O2 + 10% H2O + 88% N2 atmosphere have been used to prepare monolith catalysts, and the oxygen storage capacity (OSC) of the latter has been measured using a gas analysis setup. As the proportion of Al2O 3 in the composite is raised, the mixing uniformity and degree of dispersion of Ce x Zr1-x O2-δ particles increase, their chemical composition becomes homogeneous, and the amount of cerium involved in oxidation and reduction increases. The composite containing 50 wt % Al2O3 is a mixture of Ce x Zr 1-x O2-δ and Al2O3 crystallites, whose size is practically unaffected by calcination. The (Pt/Al2O3 + Al2O3-Ce 0.75Zr0.25O2) based on this composite has the highest OSC and is the most active. For this reason, full-scale testing of this catalyst is recommended. © 2013 Pleiades Publishing, Ltd.

Processes of melting the samples of industrial AK6 aluminum alloy in cast and homogenized states are studied using thermal analysis with the subsequent numerical differentiation with respect to time of heating curves in a temperature range from 300 to 670°C. The temperatures of nonequilibrium solidus, equilibrium solidus, and liquidus are evaluated. The microstructure of cast and homogenized alloy samples is studied and the local chemical composition of the aluminum host and phases is determined. © 2013 Allerton Press, Inc.

Since the introduction to modified 9Cr-1Mo steel (Gr.91) in 1982, new grades of creep strength enhanced ferritic (CSEF) steels including the Gr.91 have been developed and practically used in the power plants worldwide in 1990s to date increasing the steam temperature to improve thermal efficiency for energy conservation and reduction of CO 2 emission. The chemistry and heat treatment conditions for these CSEF steels are highly optimized and the elevated temperature properties such as creep strength are strongly influenced by the heat and strain cycles during the material manufacturing and fabrication. These steels have already been included into the international codes and standards, however a number of failure experiences with these steels throughout the manufacturing, fabrication and services have been reported. The American Society of Mechanical Engineers (ASME), Boiler and Pressure Vessel Code Committee has discussed on the material issues and taken the actions to improve or revise the specification of these steels based on the latest technical information and discussion results. This paper presents the recent status of ASME Code on CSEF steels.

Cataloged from PDF version of article. In this paper, chemical composition uniformity in amorphous/nanocrystallization medical-grade stainless steel (ASTM ID: F2581) sintered with a Mn–Si additive was studied via scanning electron microscopy, energy dispersive X-ray spectroscopy, and transmission electron microscopy. The results show that as a result of sintering at 1000 °C, no dissociation of Mn–Si additive particles embedded in the stainless steel matrix occurs. In contrast, sintering at 1050 °C develops a relatively homogeneous microstructure from the chemical composition viewpoint. The aforementioned phenomena are explained by liquation of the Mn–Si eutectic additive, thereby wetting of the main powder particles, penetrating into the particle contacts and pore zones via capillary forces, and providing a path of high diffusivity. © 2012 Elsevier B.V. All rights reserved.

This study evaluated the bacterial toxicity of lanthanum oxide micron and nano sized particles using shake flask method against gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli, Pseudomonas aeruginosa) bacteria. Particle size, morphology and chemical composition were determined using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Results indicated that lanthanum oxide nanoparticles showed antimicrobial activity against Staphylococcus aureus, but not against Escherichia coli and Pseudomonas aeruginosa. It was speculated that lanthanum oxide produced this effect by interacting with the gram-positive bacterial cell wall. Furthermore, lanthanum oxide bulk particles were found to enhance the pyocyanin pigment production in Pseudomonas aeruginosa. � 2012 The Chinese Society of Rare Earths.

The effect of the chemical composition in Si/Ge-based superlattices on their thermal conductivity has been investigated using molecular dynamics simulations. Simulation cells of Ge/SiGe superlattices have been generated with different concentration profiles such that the Si concentration follows a step-like, a tooth-saw, a Gaussian, and a gamma-type function in direction of the heat flux. The step-like and tooth-saw profiles mimic ideally sharp interfaces, whereas Gaussian and gamma-type profiles are smooth functions imitating atomic diffusion at the interface as obtained experimentally. Symmetry effects have been investigated comparing the symmetric profiles of the step-like and the Gaussian function to the asymmetric profiles of the tooth-saw and the gamma-type function. At longer sample length and similar degree of interdiffusion, the thermal conductivity is found to be lower in asymmetric profiles. Furthermore, it is found that with smooth concentration profiles where atomic diffusion at the interface takes place the thermal conductivity is higher compared to systems with atomically sharp concentration profiles.

cited By 2; International audience; In spite of the current prevalence of the CVD-based processes, the electric arc remains an interesting process for the synthesis of carbon nanoforms, thanks to its versatility, robustness and easiness. It also allows performing in-situ substitution of carbon atoms by hetero-elements in the graphene lattice. Our work aims to establish a correlation between the plasma properties, type and chemical composition (and the substitution rate) of the obtained single-wall carbon nanotubes. The plasma was characterized by optical emission spectroscopy and the products were analyzed by high resolution transmission electron microscopy and core level Electron Energy-Loss Spectroscopy (EELS). Results show that a high boron content leads to a plasma temperature decrease and hinders the formation of nanotubes. This effect can be compensated by increasing the arc current and/or yttrium content. The optimal conditions for the synthesis of boron- and/or nitrogen-substituted nanotubes correspond to a high axial plasma temperature associated to a strong radial gradient. EELS analysis confirmed that the boron incorporates into the graphenic lattice.

In this work, the thermal expansion behavior and the structure configuration evolution of glasses were studied. Degree of freedom based on the topological constraint theory is correlated with configuration evolution; considering the chemical composition and the configuration change, the analytical equation for calculating the thermal expansion coefficient of glasses from degree of freedom was derived. The thermal expansion of typical silicate and chalcogenide glasses was examined by calculating their thermal expansion coefficients (TEC) using the approach stated above. The results showed that this approach was energetically favorable for glass materials and revealed the corresponding underlying essence from viewpoint of configuration entropy. This work establishes a configuration-based methodology to calculate the thermal expansion coefficient of glasses that, lack periodic order.

Date of Conference: 18-22 April 2016 Conference Name: 18th CIRP Conference on Electro Physical and Chemical Machining, ISEM-XVIII 2016 Fabrication of micro needles, which reduce pain during insertion and lessen tissue injury, has recently attracted great interest. Different manufacturing systems have been utilized for the advancement of micro needles such as two-photon photo polymerization, bulk lithography, droplet-borne air blowing and injection molding [1]. This paper proposes a micro fabrication process for polymer micro needles, using DLP based projection-based stereo lithography that is capable of fabricating micro-needles using biocompatible polymers. The fabrication in the experimental setup is performed with continuous movement of the platform in the vertical direction hence good surface quality is obtained. The influence of polymerization time, light intensity of DLP projector and chemical composition of the resins on the production speed and the geometrical accuracy of the micro needles have been studied. The length and the tip diameter of the micro needle are shown to be controlled through these factors. The length and tip diameter of the fabricated micro needles were observed using SEM and optical microscope and measured to be around 520 μm and 40 μm, respectively. The results indicate that polymer micro needles with appropriate geometry can be fabricated using this technique. © 2016 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.

Gallium nitride films were grown by hollow cathode plasma-assisted atomic layer deposition using triethylgallium and N-2/H-2 plasma. An optimized recipe for GaN film was developed, and the effect of substrate temperature was studied in both self-limiting growth window and thermal decomposition-limited growth region. With increased substrate temperature, film crystallinity improved, and the optical band edge decreased from 3.60 to 3.52 eV. The refractive index and reflectivity in Reststrahlen band increased with the substrate temperature. Compressive strain is observed for both samples, and the surface roughness is observed to increase with the substrate temperature. Despite these temperature dependent material properties, the chemical composition, E-1(TO), phonon position, and crystalline phases present in the GaN film were relatively independent from growth temperature. (C) 2015 American Vacuum Society.

Cataloged from PDF version of article. Aluminum nitride (AlN) hollow nanofibers were synthesized via plasma-enhanced atomic layer deposition using sacrificial electrospun polymeric nanofiber templates having different average fiber diameters (~70, ~330, and ~740 nm). Depositions were carried out at 200°C using trimethylaluminum and ammonia precursors. AlN-coated nanofibers were calcined subsequently at 500°C for 2 h to remove the sacrificial polymeric nanofiber template. SEM studies have shown that there is a critical wall thickness value depending on the template's average fiber diameter for AlN hollow nanofibers to preserve their shapes after the template has been removed by calcination. Best morphologies were observed for AlN hollow nanofibers prepared by depositing 800 cycles (corresponding to ~69 nm) on nanofiber templates having ~330 nm average fiber diameter. TEM images indicated uniform wall thicknesses of ~65 nm along the fiber axes for samples prepared using templates having ~70 and ~330 nm average fiber diameters. Synthesized AlN hollow nanofibers were polycrystalline with a hexagonal crystal structure as determined by high-resolution TEM and selected area electron diffraction. Chemical compositions of coated and calcined samples were studied using X-ray photoelectron spectroscopy (XPS). High-resolution XPS spectra confirmed the presence of AlN. © 2012 The American Ceramic Society