Highly enhanced energy storage properties of H2O2-hydroxylated rare earth ferrites (LaFeO3 and GdFeO3) nanofillers in poly(vinylidene fluoride)-based nanocomposite films

Journal of Materials Science: Materials in Electronics - Pure PVDF has higher breakdown strength but low dielectric and ferroelectric properties. Thus, we synthesized the LaFeO3 and GdFeO3...     

4D Printing of Shape Memory Materials for Textiles: Mechanism,Mathematical Modeling,and Challenges

Shape memory materials (SMMs) in 3D printing (3DP) technology garnered much attention due to their ability to respond to external stimuli, which direct this technology toward an emerging area of research, “4D printing (4DP) technology.” In contrast to classical 3D printed objects, the fourth dimension, time, allows printed objects to undergo significant changes in shape, size, or color when subjected to external stimuli. Highly precise and calibrated 4D materials, which can perform together to achieve robust 4D objects, are in great demand in various fields such as military applications, space suits, robotic systems, apparel, healthcare, sports, etc. This review, for the first time, to the best of the authors’ knowledge, focuses on recent advances in SMMs (e.g., polymers, metals, etc.) based wearable smart textiles and fashion goods. This review integrates the basic overview of 3DP technology, fabrication methods, the transition of 3DP to 4DP, the chemistry behind the fundamental working principles of 4D printed objects, materials selection for smart textiles and fashion goods. The central part summarizes the effect of major external stimuli on 4D textile materials followed by the major applications. Lastly, prospects and challenges are discussed, so that future researchers can continue the progress of this technology.     

The Effect of Interface Cracks on the Electrical Performance of Solar Cells

Among a variety of solar cell types, thin-film solar cells have been rigorously investigated as cost-effective and efficient solar cells. In many cases, flexible solar cells are also fabricated as thin films and undergo frequent stress due to the rolling and bending modes of applications. These frequent motions result in crack initiation and propagation (including delamination) in the thin-film solar cells, which cause degradation in efficiency. Reliability evaluation of solar cells is essential for developing a new type of solar cell. In this paper, we investigated the effect of layer delamination and grain boundary crack on 3D thin-film solar cells. We used finite element method simulation for modeling of both electrical performance and cracked structure of 3D solar cells. Through simulations, we quantitatively calculated the effect of delamination length on 3D copper indium gallium diselenide (CIGS) solar cell performance. Moreover, it was confirmed that the grain boundary of CIGS could improve the solar cell performance and that grain boundary cracks could decrease cell performance by altering the open circuit voltage. In this paper, the investigated material is a CIGS solar cell, but our method can be applied to general polycrystalline solar cells.     

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.     

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.     

First Principle and Experimental Study for Site Preferences of Formability Improved Alloying Elements in Mg Crystal

Some alloying elements (Al, Er, Gd, Li, Mn, Sn, Y, Zn) were proved recently by calculations or experiments to improve the formability of Mg alloys, but ignoring their site preference in Mg crystals during the calculated process. A crystallographic model was built via first principle calculations to predict the site preferences of these elements. Regularities between doping elements and site preferences were summarized. Meanwhile, in the basis of the crystallographic model, a series of formulas were deduced combining the diffraction law. It predicted that a crystal plane with abnormal XRD peak intensity of the Mg-based solid solutions, compared to that of the pure Mg, prefers to possess solute atoms. Thus, three single-phase solid solution alloys were then prepared through an original In-situ Solution Treatment, and their XRD patterns were compared. Finally, the experiment further described the site preferences of these solute atoms in Mg crystal, verifying the calculation results.     

Effects of Solution Treatment Temperatures on Microstructure and Mechanical Properties of TIG–MIG Hybrid Arc Additive Manufactured 5356 Aluminum Alloy

A novel additive manufacturing method with TIG–MIG hybrid heat source was applied for fabricating 5356 aluminum alloy component. In this paper the microstructure evolution, mechanical properties and fracture morphologies of both as-deposited and heat-treated component were investigated, and how these were affected by different heat-treated temperature. The as-deposited microstructure showed dominant equiaxed grains with second phase, and the size of them is coarse in the bottom region, medium in the middle region and fine in the top region owing to different thermal cycling conditions. Compared with as-deposited microstructure, the size of grain becomes large and second phases gradually dissolve in the matrix as heat-treated temperature increase. Different microstructures determine the mechanical properties of component. Results show that average ultimate tensile strength enhances from 226 to 270 MPa and average microhardness increases from 64.2 to 75.3 HV0.1 but ductility decreases from 33 to 6.5% with heat-treated temperature increasing. For all components, the tensile properties are almost the same in the vertical direction (Z) and horizontal direction (Y) due to equiaxed grains, which exhibits isotropy, and the mechanisms of these are analyzed in detailed. In general, the results demonstrate that hybrid arc heat source has the potential to fabricate aluminum alloy component.