Variables Applicable to Benchmarking of Tap-Hole Life-Cycle Management Practices in Coke-Bed-Based Ferroalloy Production

Benchmarking is a tool available to furnace operators to evaluate their tap-hole life-cycle management practices against those of their peers. It allows furnace operators to challenge their own practices in order to increase furnace utilization. To facilitate the benchmarking process, it is necessary to define the variables to be considered and how they relate to one another. This article develops, from the literature and industry interviews, a holistic conceptualization of the variables that form part of tap-hole lifecycle management and performance. Specifically, the article focuses on the variables related to coke-bed-based processes (FeCr, SiMn, and HCFeMn) applying SAF technology of circular design.     

Removal of Antimony and Bismuth from Copper Electrorefining Electrolyte: Part II—An Investigation of Two Proprietary Solvent Extraction Extractants

Antimony and bismuth recovery from copper electrorefining electrolyte could reduce the impacts of these problem elements and produce a new primary source for them. Two proprietary phosphonic acid ester extractants were examined (REX-1 and REX-2) for the removal of antimony and bismuth from copper electrorefining electrolytes. Experimentation included shakeout and break tests to determine the basic parameters for the extractants in terms of maximum loading, break times, and extraction and stripping efficiency. Five permutations of extractant mixtures (100 wt.% REX-1 and 25 wt.%, 50 wt.%, 75 wt.% and 100 wt.% REX-2) were studied. It was determined that REX-2 was able to extract Sb and Bi from the electrolyte, but required some mixture with REX-1 to better facilitate stripping with 400 g/L sulfuric acid. The laboratory electrorefining electrolyte containing glue had faster disengagement times than a synthetic solution without glue.     

Synthesis of Flexible Graphene/Polymer Composites for Supercapacitor Applications

In this paper, the graphene was synthesized using biocompatible cellulosic component from onions. Onion epidermal cells were chosen as raw material. During heating at high temperature, the bonding among atoms in material was rearranged and forms two-dimensional hexagonal carbon layer (graphene). The characterization of synthesized graphene was done by x-ray diffractometer, Raman spectrometer and field emission scanning electron microscopy, respectively. An attempt has been taken to form the capacitors with two different current collector electrodes, anticipating the performance of the supercapacitors. The observed capacitance values as-obtained for Al and Au current collector were 1.3 μF and 6.08 μF, respectively. However, when thermally exfoliated graphene was used as an electrode on Al and Au current collector, the capacitance value was drastically increased and found to be 1.6 and 41.25 μF, respectively.     

Biocompatibility of Hydrogen-Diluted Amorphous Silicon Carbide Thin Films for Artificial Heart Valve Coating

Amorphous silicon carbide (a-SiC:H) thin films were synthesized using trichloromethylsilane by a hot wire chemical vapor deposition process. The deposited films were characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, x-ray diffraction and x-ray photoelectron spectroscopy to confirm its chemical bonding, structural network and composition of the a-SiC:H films. The optical microscopy images reveal that hydrogen dilution increased the surface roughness and pore density of a-SiC:H thin film. The Raman spectroscopy and FTIR spectra reveal chemical network consisting of Si-Si, C-C and Si-C bonds, respectively. The XRD spectroscopy and Raman spectroscopy indicate a-SiC:H still has short-range order. In addition, in vitro cytotoxicity test ensures the behavior of cell–semiconductor hybrid to monitor the proper coordination. The live–dead assays and MTT assay reveal an increase in green nucleus cell, and cell viability is greater than 88%, respectively, showing non-toxic nature of prepared a-SiC:H film. Moreover, the result indicated by direct contact assay, and cell prefers to adhere and proliferate on a-SiC:H thin films having a positive effect as artificial heart valve coating material.     

Plasma-Sprayed Hydroxylapatite Coatings as Biocompatible Intermediaries Between Inorganic Implant Surfaces and Living Tissue

The present contribution discusses critical aspects of the thermal alteration that HAp particles undergo when passing along the extremely hot plasma jet. This heat treatment leads to dehydroxylated phases such as oxyhydroxylapatite/oxyapatite as well as thermal decomposition products such as tri- and tetracalcium phosphates, and quenched phases in the form of amorphous calcium phosphate (ACP) of variable composition. The contribution also includes studying the influence bioinert TiO₂ bond coats have on adhesion, crystallinity, and composition of HAp coatings. Moreover, the question is being addressed whether oxyapatite might exist as a (meta)stable phase or whether its occurrence is merely an ephemeral event. In addition, the article deals with the role that HAp coatings are playing during in vitro interaction with simulated body fluid (SBF) resembling the composition of extracellular fluid (ECF). The biological and biomechanical advantages of using HAp coatings for medical implants as well as salient aspects of their biomineralization and osseointegration will be discussed in some detail.     

Measurement of Young’s Modulus and Poisson’s Ratio of Thermal Barrier Coating Based on Bending of Three-Layered Plate

Thermal barrier coatings (TBCs) are used to protect the hot sections of gas turbine engines and airplane engines. A TBC system comprises a substrate, bond coat, and TBC topcoat. The development of an accurate method for determining the Young’s modulus and Poisson’s ratio of TBC using a multilayered specimen is of importance. In this study, we applied the bending theory of a laminated plate to a three-layered material and proposed models to determine the Young’s modulus and Poisson’s ratio of the TBC layer using the bending strain of the TBC system specimen. Three methods were developed by utilizing (i) the coating biaxial strain, (ii) substrate biaxial strain, or (iii) coating and substrate biaxial strains. Subsequently, we determined appropriate dimensions of the specimen and span by using three-dimensional finite element analysis, and numerically verified the usefulness of the three proposed methods. However, the Young’s modulus and Poisson’s ratio determined using the multilayered specimen with a substrate are sensitive to experimental errors. Therefore, we evaluated the sensitivity of the three proposed methods to experimental error, and we determined the most insensitive method among them. Finally, we experimentally demonstrated the usefulness of this method.     

Thermodynamic Properties of Superionic Phase Ag<Subscript>4</Subscript>HgSe<Subscript>2</Subscript>I<Subscript>2</Subscript> Determined by the EMF Method

Triangulation of the Ag-Hg-Se-I system in the vicinity of quaternary phase Ag₄HgSe₂I₂ was performed by differential thermal analysis, X-ray diffraction and electromotive force (EMF) methods. The spatial position of the phase region Ag₄HgSe₂I₂-Se-HgI₂ regarding the figurative point of silver was used to write the chemical reaction of formation of Ag₄HgSe₂I₂. The EMF measurements were carried out by applying an electrochemical cell: (–) C|Ag|Ag₂GeS₃ glass|Ag₄HgSe₂I₂, HgI₂, Se|C (+), where C is graphite and Ag₂GeS₃ glass is the fast purely Ag⁺ ions conducting electrolyte. The linear dependence of the EMF of the electrochemical cell on temperature was used to determine the standard thermodynamic values of Ag₄HgSe₂I₂ for the first time.     

Prediction of Glass Forming Ability Through High Throughput Calculation

In this work, high throughput calculation (HTC) is used to identify composition regions with good glass forming ability (GFA) in the Al-Cu-Zr, Cu-Ni-Zr, Cu-Ti-Zr, Cu-Ni-Ti-Zr, Al-Cu-Ni-Ti-Zr, Mg-Ca-Cu, and Mg-Ca-Ni systems. The predicted composition regions agree well with those observed by experiments in the ternary systems, while less satisfactory agreement is found in the Cu-Ni-Ti-Zr quaternary and the Al-Cu-Ni-Ti-Zr quinary systems. The possible causes that lead to the deviation in the higher order systems are discussed. The major advantage of the HTC method used in this study is that it is simple and can be easily applied to multicomponent systems. The color maps of liquidus temperature and solidification range obtained by HTC provide a valuable guidance to the experimentalists, thus they can focus on the composition regions with high potential of forming bulk metallic glasses, avoid unnecessary trial-and-error test and save time and cost. This approach can also be combined with other criteria to filter compositions with better GFA.     

Thermodynamic Modeling of Pure Co Accounting Two Magnetic States for the Fcc Phase

The thermodynamic functions of the pure Co were assessed using CALPAHD method for the third generation thermodynamic databases. To model the magnetic properties of the cobalt, a two-state magnetic model was accounted for the fcc phase. Calculated results were compared with the experimental information and a good fit to the experimental data was achieved.