bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effect of molar ratio and flow velocity on the surface area required for pertraction of a Zr/Hf mixture
Authors: Malan D , van der Westhuizen DJ , Neomagus HWJP , Krieg HM 
Published: November 2019

Abstract
Zirconium (Zr) and hafnium (Hf) need to be separated before being used in nuclear applications. Equilibria data have shown that Hf can be selectively extracted over Zr from a sulphate medium using organophosphorus extractants. This study investigated a modification of Zr and Hf solvent extraction whereby a hollow-fibre membrane contactor was used to separate the aqueous and organic phases, termed pertraction (PX). The aim of the study was to investigate the effects of the molar D2EHPA:Hf ratio and the volumetric flow rate on the estimated surface area required for an industrial PX extraction unit. Equilibrium experiments showed that the maximum separation factor (8.8) was found at D2EHPA:Hf ratio of 350:1. Mass transfer coefficients and kinetic selectivities of hafnium and zirconium were determined using a hollow fibre PX set-up. Variables investigated were: i) D2EHPA concentration, and ii) volumetric flow rate at a constant organic to aqueous ratio. The mass transfer coefficients of hafnium and zirconium and the separation ratio increased at higher flow rates. The best experimental conditions estimate that an industrial extraction unit capable of producing 500 ton per annum nuclear grade zirconium would require approximately 3 200 m2 membrane surface area, at a volumetric flow rate of 1.7 m3.h-1 when operated under similar conditions to those in this study.
Density functional theory study of TiPd alloying with Os as potential high temperature shape memory alloys
Authors: Diale R G , Modiba R , Ngoepe P E , Chauke H R 
Published: November 2019

Abstract
Ti50Pd50 alloy exhibits thermoelastic martensitic phase transformation above 823 K and has the potential for high temperature shape memory material applications. Previous studies showed that this alloy is mechanically unstable with a negative C’ at room temperature. A systematic investigation of the structural, thermodynamic, electronic and elastic properties of TiPdOs is conducted using a first-principles calculation based on density functional theory. The calculated heats of formation show that this compound is thermodynamically stable as Os content is increased. It is found that an increase in Os content stabilizes the TiPd with a positive Cx2032; observed above 18.25 at. %. An increase in Os content results in an increase of the Bulk modulus and Young’s modulus above 18.25 at. %. Anisotropy factor and Vickers hardness are studied and hardness is found to increase with an increase in Os content. The results suggest that the stability of the B2 phase can be significantly enhanced by the addition of Os in TiPd alloy. These findings have important applications for future materials design in aerospace industries.
Exploring the potential of N-acylated chitosan for the removal of toxic pollutants from wastewater
Authors: Naidoo S , Nomadolo N , Matshe W M R , Cele Z , Balogun M 
Published: November 2019

Abstract
Modified chitosan was prepared by chemical derivatisation using caproyl and palmitoyl fatty acid chains. The performance of the materials on the removal of phosphates in aqueous solutions was evaluated through a series of batch adsorption experiments. The phosphate adsorption studies showed enhanced adsorption efficiencies for caproyl chitosan (63%) and for palmitoyl chitosan (71%) in aqueous solutions containing phosphate at a pH of 6.2. The pristine and modified chitosans showed increases in the removal efficiency at an optimal solution pH of 4. The adsorption kinetics studies performed on palmitoyl-chitosan indicated that a contact time of approximately 30 minutes is required to reach equilibrium at solution concentrations ranging from 10-20 mg/l. Co-existing anions such as nitrates and sulphates do affect the phosphate removal efficiency of modified chitosans in aqueous solutions. This study demonstrates that modified chitosans has the potential of being used as a rigid and degradable material for water treatment.
Engineering design highlights of high-efficiency slab casters relocated at Baosteel Zhanjiang
Authors: Ding X L , Feng C B , Liu Q , Yan J W , Zhang Y D , Luo G Q 
Published: November 2019

Abstract
Baosteel Group decided in 2013 to relocate the main segment equipment of the 2 single-strand 2,300 mm slab casters which were shut down at its Luojing Plant to the Zhanjiang Plant and transform them into an upgraded two-strand slab caster. CISDI was contracted to supply the overall design and the main equipment packages. CISDI employed a couple of advanced technologies including online mould width adjustment, top-inserted dummy bar, dual strand tracking and casting at constant speeds to enhance the production capacity of the caster; for sake of Opex saving CISDI also optimized the arrangements of the independent mechanical maintenance shop, utilities of compact design, cooling water valve stations and hydraulic valve stations of compact designs, and open-air cooling water pump station, etc.
Crystallization processes and magnetic properties of FeCoZrMB (M=Nb, V, Cr, Ti) amorphous alloys
Authors: Yu W Q , Lu L P 
Published: November 2019

Abstract
A series of Fe40Co40Zr8M2B10 (M=Nb, V, Cr, Ti, W, Al) alloys were prepared using melt-spinning. The thermal curve, structure and magnetic property of alloys are examined. Because of different negative heat of mixing between elements, only Fe40Co40Zr8M2B10 (M=Nb, V, Cr, Ti) alloys form amorphous structure. These amorphous alloys are annealed at different temperatures under vacuum conditions. The crystallization processes of four amorphous alloys are similar. In the primary stage of crystallization process, only α-Fe(Co) phase precipitates and Co element mainly distributes in the residual amorphous. For the four alloys after annealing at 550°C, there is a few differences in saturation magnetization (
M
s
) and coercivity (
H
c
) due to their different microstructures.
Investigation of temperature and CO2 concentration in converter gas flames by a combustion diagnostic system based on TDLAS
Authors: Liu Y , Wang J S , Xue Q G , Zuo H B , She X F 
Published: November 2019

Abstract
In this study, a novel combustion diagnostic system based on tunable diode laser absorption spectroscopy (TDLAS) was developed to simultaneously measure the temperature and CO2 concentration in flames on a turbulent partly premixed burner. This system simulates harsh industrial combustion environment and enables in situ measurements of non-uniform temperature and CO2 concentration distributions in converter gas-air flames. A mixture of CO, CO2, and N2 with the volume percentage ratio 80:15:5 was injected into the fuel stream to simulate effects of converter gas. Temperature and CO2 concentration in flames along the axial direction at the burner centerline were simultaneously measured by online TDLAS. The flame temperature was compared with that obtained by thermocouple measurement. The CO2 concentration was compared with those of samples taken from the flame. The results of online TDLAS measurements showed the same variation trend as temperature in the core of the flames measured using thermocouples and CO2 concentration obtained from the analysis of samples. This work proved that non-uniform temperature and CO2 concentration distributions in converter gas flames could be measured by this system and laid the foundation for further study about the effects of CO2 and/or N2 addition on converter gas/air flames.
Study on the process of TC4 powders prepared by electrode induction melting gas atomization for laser 3D printing
Authors: Xie B , Fan Y Z , Miao Q D 
Published: November 2019

Abstract
This study employed TC4 rod as raw material to fabricate TC4 powders for laser 3D printing via electrode induction melting gas atomization (EIGA). The morphologies, phase compositions, particle size distributions, apparent densities and flowabilities of the powders were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), laser particle size analyzer (LPS) and Hall flowmeter, respectively. Moreover, the effects of gas atomization pressure and melting temperature on the yield of TC4 powders for laser 3D printing were studied. The results showed that TC4 powders morphology was nearly regular spherical. The particle size of TC4 powders showed a single peak normal distribution, mainly distributed in the range of 15−180 μm. The powder was α’−Ti of a single phase solid solution. The optimum parameters were gas atomization pressure of 5MPa, melting temperature of 1750°. Under the optimized condition, the average particle size D50 was 60.2 μm, the yield of printable TC4 powders was 35.6%, the flowability was 41.2 s/50g, the apparent density was 2.76 g/cm3 and oxygen content was 800 ppm, which was in line with the ASTM test standard and was conformed to the requirement for laser 3D printing.
Research of unpolluted deoxidization technology with applied electric field
Authors: Jia J X , Guo Q T , Li D G , Liao X W , Peng C L 
Published: November 2019

Abstract
A commercial experiment system of unpolluted deoxidization with applied electric field is designed and fabricated based on laboratory and pilot research. A simulation model for the electrochemical deoxidization system between molten steel and slag with direct current electric field is found and calculated. A series of research work has been carried out in order to explore the influence of the various technology parameters on the electrochemical deoxidization efficiency. The effects and influences of the electric field parameters, the electrode parameters, the properties of the molten slag and molten steel on the distribution of the current density in the electrochemical deoxidization system are analyzed according to the simulation experiments and the commercial experiments. The simulation results are verified based on experiments. The result shows that the oxygen transfers from the molten slag into the molten steel without electric field because of the high oxidizing slag. And the electrochemical deoxidization can be carried out effectively with the application of electric field. The maximum deoxidization rate can reach to 11.3×10−6·min−1 and the deoxidization rate can be improved by increasing oxygen ion current. Increasing both of the mass transfer coefficient and the reaction interface area can increase the oxygen ion current between the steel and slag.
Validation of constitutive models for experimental stress-strain relationship of high-strength steel sheets under uniaxial tension
Authors: Chen J J , Lian C W , Lin J P 
Published: November 2019

Abstract
The constitutive relationship between stress and strain is one of the important issues in numerical simulation of metal forming. For steel, there are two kinds of constitutive models wildly used. One is power law like Ludwik and Swift. The other is saturation models like Voce and Hockett-Sherby. It is necessary to determine the most appropriate model and parameters for newly developed high strength steels. In order to describe the ultra-high strength dual phase and quenching and partitioning steels, uniaxial tensile tests with the aid of digital image correlation techniques were performed to analyse the strain field over the whole gauge section as well as the element close to the necking point. Through experimental data analysis and numerical fitting, the validity of different models have been confirmed. It shows that equation of Hockett-Sherby model has the best fitting accuracy and high strength steels require a model with more parameters. The extrapolated weighting coefficient of combined Swift and Hockett-Sherby models is characterized, which is proved to improve the accuracy of the numerical simulation of forming of ultra-high strength steels based on the conventional tensile tests.
A modified mathematical model for end-point carbon prediction of BOF based on off-gas analysis
Authors: Lin W H , Sun J K , Zhou K X , Liu Q , Jiao S Q , Zhang J S , Su X , Liu M , Huang Y C , Li N 
Published: November 2019

Abstract
Several models for end-point carbon prediction of BOF(Basic Oxygen Furnace) based on off-gas analysis were studied in this paper. The advantages and disadvantages of the integral model, the exponential decay model and the cubic fitting model were analyzed respectively. Based on analysis of the characteristics of the decarburization rate curve, a new exponential model was established by the introduction of a correction algorithm. The principle of the proposed model involves applying the decarburization rate curve and the descending gradient of the historical heats to obtain the average decarburization curve and reference decarburization efficiency coefficient using the regression fitting method. According to the deviation between the actual and the predicted decarburization curves, the decarburization efficiency coefficient was corrected to improve the prediction accuracy. Plant trials were carried out in a 210 t converter to compare the performance of the mentioned models. The results showed that the new model exhibited better adaptability and higher accuracy than the other ones. The hit ratio of the new model reached more than 90% for the prediction of end-point carbon content within a tolerance of ±0.02%.
Probability based global sensitivity analysis of fatigue reliability of steel structures
Authors: Kala Z 
Published: November 2019

Abstract
This article focuses on reliability-oriented global sensitivity analysis of the fatigue limit state of a steel member stressed by many times repeated loading. The fatigue limit state is associated with fatigue failure, which is caused by brittle fracture due to propagation of a fatigue crack from initial to critical size. The fatigue crack propagation is analysed using linear fracture mechanics. The fundamental question in terms of structural reliability is how significant is the effect of input random quantities on the probability of failure. A new type of global sensitivity analysis subordinated to a contrast identified the equivalent stress range and initial edge crack length as random quantities that most significantly influence the failure probability. The new findings obtained using the contrast-based global sensitivity analyses show interaction effects that are unusually strong in comparison with some results of Sobol’s sensitivity analysis aimed at the reliability of structures. The sensitivity indices are estimated using double-nested-loop simulation of the Latin Hypercube Sampling method.
Formation and decomposition of Widmanstätten austenite in GOES belt-casted strips
Authors: Vodárek V , Reip C-P , Smetana B , Volodarskaja A 
Published: November 2019

Abstract
This contribution deals with the formation and decomposition of Widmanstätten austenite during solidification of the thin belt-casted strips made of a grain oriented electrical steel (GOES). Solidification of liquid steel started with the formation of δ-ferrite. Cooling in the δ + γ phase field resulted in the formation of a small fraction of Widmanstätten austenite by displacive mechanism accompanied by carbon partition. Widmanstätten austenite laths formed flat low energy interface facets along ferrite grain boundaries. In order to minimize the interfacial energy, ferrite grain boundaries in the vicinity of flat austenite/ferrite facets migrated. It resulted in the formation of either straight or zig-zag ferrite boundaries. Intensive precipitation of sulphides along ferrite/austenite interfaces made it possible to study the early stages of austenite decomposition at the end of the δ + γ phase field. Complex sulphides containing chromium, manganese, iron and copper were identified as the Cr2CuS4 phase. Decomposition of austenite started with the formation of epitaxial ferrite. This was accompanied by further partitioning of carbon into remaining austenite. The growth of epitaxial ferrite into the flat ferrite/austenite interface facets along ferrite grain boundaries resulted in a wavy shape of these boundaries. Finally, remaining carbon rich austenite transformed either to pearlite or plate martensite.
Study of grain distribution during friction stir welding of Al-Zn-Mg alloys using numerical simulation
Authors: Wu Y F , Yu J , Yang Z , Deng Y L 
Published: November 2019

Abstract
During friction stir welding (FSW) of Al-Zn-Mg alloys, the grain size of the welded material significantly affects its mechanical properties. In this study, the FSW process was simulated using the finite element method (FEM). Subsequently, the Zener-Hollomon parameters and grain size were calculated using the results of the stimulation of the temperature and strain rate fields. Also, the accuracy of numerical simulation was proved by experiments. It was found that the Zener-Hollomon relationship correctly predicted the grain size for the weld stirring zone (SZ) and thermal-mechanical affected zone (TMAZ), and we concluded that low rotating and high welding speeds resulted in smaller grain sizes for the SZ. Moreover, the high welding speed could effectively improve the grain condition at the edge of the TMAZ and the specific relationship between Zener-Hollomon parameters and the average grain diameter of SZ can be expressed as: Z = 9.09 × 1013
d
−4.74.
Fabrication of Ag micro-patterns by electrohydrodynamic jet printing
Authors: Lv H , Wang X 
Published: November 2019

Abstract
Electrohydrodynamic jet printing is a rapid manufacturing method in additive manufacturing fields, which is employed to generate micro-nano patterns, functional structures, sensors and electronics in recent years. It is a rapid manufacturing, low-cost, mask-free route to manufacture one dimensional to three dimensional structures by nanoink. In this paper, silver dots, lines and designed patterns are printed by electrohydrodynamic jet printing. The results are stable and uniform, which can be adjusted by printing parameters. With high voltage, large pulse width or small stand-off distance, the size of dots increase. By increasing frequency or decreasing shifting speed, the distance between dots becomes short, then the structures are getting into lines from dots. Multi-layer silver lines are characterized by X-ray imaging and exhibit good absorption of X-ray, leading to the significant radiation attenuation effectiveness. The printed silver structures are good candidates for radiation shielding in electronics and circuit boards.
Constitutive modeling of dynamic recrystallization and precipitation behavior of Nb and Ti of Q1030 high strength steel
Authors: Wang J J , Kang Y L , Liu Y L , Yu H 
Published: November 2019

Abstract
The thermal deformation and precipitation behavior at 900-1100° and strain rate of 0.1-5s−1 were studied by Gleeble-3800 thermal simulator of Q1030 high strength steel. The activation energy of hot deformation in austenite region was determined by regression method, and the hot deformation equation of the Q1030 high strength steel was established. The critical strain and peak strain of dynamic recrystallization were predicted accurately by fitting the inflection point with cubic polynomial of curve of Q1030 high strength steel, and relationship between critical strain and Z parameter was established. Finally, the precipitation behavior of Nb and Ti particles during low strain rate deformation was studied, the results show that the precipitated phases in steel are rectangular TiN, quadratic (Nb, Ti) (C, N) carbonitride, elliptical (Nb, Ti) C carbide and NbC. Thermodynamic calculation shows that the order of precipitation of the second phase in steel is TiN, TiC, NbC and NbN.
Anomalous concentration dependence of the thermal conductivity of refractory sintered binary nano-composites TiN-ALN and ZrC-ZrB2
Authors: Zarichniak Y , Ordanyan S 
Published: November 2019

Abstract
An abnormal concentration dependence of the thermal conductivity of nanocomposites Titanium Nitride-Aluminum Nitride and zirconium carbide-zirconium diboride has been experimentally established from the volume fraction of components. An explanation of the nature of the anomalous dependence and a technique for an approximate estimation of the dependence of the thermal conductivity of a nanocomposite on the volume fraction of components are proposed. Oxygen-free refractory compounds - covalent and metal-like active investigated in the development of new ceramic materials used for achieving higher physical and mechanical characteristics as well as for use in extreme conditions in mechanical engineering, nuclear engineering, aviation, special equipment. The development of technology is constantly stimulates the creation of new materials, which must manifest a complex of properties rarely show by one substance, such decisions cannot find the formation of composite (hetero) materials. In the case of eutectic systems with diffusive non-interacting refractory components, used for the synthesis of composite ceramic materials in a highly thermodynamic state, the possibility of co-building a new group of ceramics with interphase boundary (of eutectics “coarse conglomerate”) with anomalous concentration dependences of the physical and mechanical characteristics of composite materials (flexural strength and modulus of elasticity, super plasticity – elongation more than 500%, tensile, strength and fracture toughness) and thermal properties (thermal conductivity and thermal diffusivity) [1-3].
Functionalization of Fe3O4/TiO2/BiOCl nanocomposites using Sargassum crassifolium extract as magnetic nanophotocatalyst for cadmium sequestration
Authors: Cumba R M T , Capangpangan R Y , Alguno A C 
Published: November 2019

Abstract
We report on the synthesis of Fe3O4/TiO2/BiOCl nanocomposites using Sargassum crassifolium extract as magnetic nanophotocatalyst for cadmium sequestration. Utilization of nanotechnology via surface engineering and functionalization has been considered for heavy metals sequestration. In this work, we are going to synthesize Fe3O4/TiO2/BiOCl nanocomposites via green synthesis for cadmium heavy metal sequestration on wastewater. Synthesis of nanocomposites includes the fabrication of functionalized Fe3O4 magnetic nanoparticles using Sargassum crassifolium extract followed by the fabrication of TiO2 and finally capped with BiOCl to complete the Fe3O4/TiO2/BiOCl nanocomposites. Experimental results revealed that successful green synthesis of magnetic Fe3O4 via was observed in the Fast Fourier transform infrared spectra with the presence of Fe-O vibrations at 580 cm−1. In addition, the band around 1000 cm−1 was observed suggesting the TiO2 was successfully formed the peak around 1155 cm−1 can be attributed to Bi-Cl bond for the formation of BiOCl. Moreover, the presence of 370 nm peak in the ultraviolet-visible spectra suggests that Fe3O4/TiO2/BiOCl nanocomposites were successfully synthesized. Varied amount of cadmium on wastewater was efficiently sequestered via photocatalysis with an efficiency of about 83%. This straight forward green synthesis of Fe3O4/TiO2/BiOCl nanocomposites is a potential photocatalysts for cadmium sequestration.