Nitinol, being a shape memory and super elastic alloy, is used in medical industry. Surface modification of nitinol helps to reduce the nickel ion leaching in physiological environment. The purpose of this study is to modify the nitinol surface by the silanization technique and to conduct a comparative investigation with the bare nitinol in the aspect of leaching of nickel ion, hemocompatibility, and in vivo animal response. X-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy studies confirmed the addition of organofunctional alkoxysilane molecules through the silanization process. The histological study showed the presence of adequate number of osteoblasts in silanized nitinol. The fluorochrome labeling study depicted more new bone formation (8 and 21% higher) in silanized nitinol specimens than bare one at one and three months postoperatively. Radiology and SEM study also proved the better performance of silanized samples. The cumulative in vivo results indicate its suitability as the potential bioimplant in various orthopedic surgical uses.

The acidity of SBA-15 was tuned with the incorporation of Al+3, Ti+4, and –PrSO3H groups through sol–gel, employing molar ratios of Si/M = 10 (M = Al, Ti) and Si/S = 10. This results in mesoporous materials with the typical hexagonal structure of SBA-15, large surface areas, and great pore diameter. The incorporation of Al+3 and Ti+4 mainly leads to catalysts with both Brönsted and Lewis acid sites. The addition of sulfonic groups to these samples enhanced their surface acidity, creating preferentially Brönsted acid sites. Among the evaluated catalysts, the SBA-15-SO3H showed the highest catalytic activity, which was related to the high concentration of Lewis acid sites, and a remarkable resistance to deactivation, probably due to its low hydrophilicity. A first order kinetic equation fits well the experimental data and an activation energy of 31.5 kJ/mol similar to other reports for this reaction was calculated for the SBA-15-SO3H catalyst.

In this work, activated carbon was modified by ammonium persulfate and used as the catalyst support for CO2 hydrogenation to methanol. Then CuO and/or ZnO were loaded on the support by a facile wet-impregnation method. The obtained CuZn/C, Cu/C, and Zn/C catalysts were characterized by a series of characterization techniques including N2 physisorption, X-ray diffraction (XRD), X-ray photoelectron (XPS), and scanning and transmission electron microscopies (SEM and TEM). XRD and XPS results showed that ZnO affected the reduction of Cu2+. The TEM results showed that Cu particles were 14–18 nm for the fresh catalysts CuZn/C and Cu/C. ZnO particles were too small to be identified by TEM. The used catalysts CuZn/C and Cu/C had particle sizes of 10–25 nm and 50–60 nm, respectively. The enhanced methanol synthesis performance by ZnO could be ascribed to the morphology effect and slowing down the Cu particles sintering during the reactions.

Standard molar heat capacity, $C_{{\rm{p,m}}}^{\rm{o}}\left( T \right)$, of YbRhO3(s) was determined using a heat flux type differential scanning calorimeter from 126 to 846 K. The heat capacities in the temperature range 307 ≤ T (K) ≤ 846 were fitted into a polynomial expression and can be represented by $C_{{\rm{p,m}}}^{\rm{o}}$ (YbRhO3, s, T) [J/(K mol)] = 106.82 + 8.57 × 10−3T (K) − 9.48 × 105/T2(K). The standard molar heat capacity of YbRhO3(s), $C_{{\rm{p,m}}}^{\rm{o}}$, at 298.15 K is 98.7 J/(K mol). The standard molar Gibbs energy of formation of YbRhO3(s) was also determined using calcia stabilized zirconia as an oxide electrolyte and air as the reference electrode by the solid state electrochemical technique. The cell can be represented by (−)Pt–Rh/{Yb2O3(s) + YbRhO3(s) + Rh(s)}//CSZ//O2(p(O2) = 21.21 kPa)/Pt–Rh(+). The electromotive force was measured in the temperature range from 889 to 1110 K. The standard Gibbs energy of formation of YbRhO3(s) from elements in their standard state can be represented by ΔfGo{YbRhO3(s)}/kJ/mol(±1.62) = −1110.9 + 0.287 T (K). The heat capacity of YbRhO3(s) was used along with the data obtained from the electrochemical cell to evaluate all thermodynamic functions of YbRhO3(s).

The combined effect of B2 phase transfer and grain boundary character on mechanical properties of the Fe–6.5 wt% Si alloy was investigated. The microstructures and textures of the Fe–6.5 wt% Si alloy under four cooling modes were characterized by X-ray diffraction, transmission electron microscope, and electron backscattered diffraction. The results reveal that the maximum nano-hardness value (8.9 GPa) results from the two-step air-cooling sample, while for the two-step water-cooling sample, the minimum value (5.3 GPa) is achieved. The transformation of the B2 phase affected by the water-cooling process is a critical factor in obtaining the lower APB energy and eliminating the brittlenes. A large fraction of the coincidence site lattice boundaries that formed on the sheet experienced the two-step water-cooling process due to a uniform and sharp γ-fiber recrystallization texture comprising the {111} 〈110〉 and {111} 〈112〉 components, which enhances resistance to intercrystalline effect and improves mechanical properties in comparison with the two-step air-cooling process.

Recent advances in the additive manufacturing technology now enable fused filament fabrication of polyetheretherketone (PEEK). A standardized lumbar fusion cage design was 3D printed with different speeds of the printhead nozzle to investigate whether 3D-printed PEEK cages exhibit sufficient material properties for lumbar fusion applications. It was observed that the compressive and shear strength of the 3D-printed cages were 63–71% of the machined cages, whereas the torsion strength was 92%. The printing speed is an important printing parameter for 3D-printed PEEK, which resulted in up to 20% porosity at the highest speed of 3000 mm/min, leading to reduced cage strength. Printing speeds below 1500 mm/min can be chosen as the optimal printing speed for this printer to reduce the printing time while maintaining strength. The crystallinity of printed PEEK did not differ significantly from the as-machined PEEK cages from extruded rods, indicating that the processing provides similar microstructure.

The microstructure evolution and mechanical properties of Mg–10Gd–3Y–xZn–0.6Zr (x = 0.5, 1, and 1.5 wt%) alloys in the as-cast, solution-treated, and peak-aged conditions have been investigated systematically. The results indicate that the microstructure of the as-cast alloy with 0.5% Zn consists of α-Mg, (Mg,Zn)3RE and Mg24(RE,Zn)5 phases, while the alloy with 1.0 and 1.5% Zn consists of α-Mg, (Mg,Zn)3RE and some stacking faults. Moreover, 18R-LPSO phases are observed in the as-cast alloy with 1.5% Zn. The formation of LPSO phases involves not only stacking sequence ordered but also chemical composition ordered. After solution treatment, the Mg24(RE,Zn)5, (Mg,Zn)3RE, stacking faults, and 18R-LPSO phases transform into 14H-LPSO phases. The 14H-LPSO phase plays an important role in the improvement of mechanical properties, especially for the ductility. The β′ phase with a bco structure precipitates in the peak-aged alloys results in precipitation hardening, significantly improving the tensile strength, but it leads to poor ductility.

Centerline segregation is one of the typical internal defects, which occurs during slab continuous casting (CC). To investigate and predict the centerline segregation encountered in a continuously cast slab, a combined 3-D and 2-D hybrid simulation model for centerline segregation was developed. The average deviation between the calculated and experimented results reaches as low as 0.5%, which demonstrates that the hybrid simulation model has relatively high reliability. The centerline segregation of the slab was predicted accurately. The results show that macrosegregation occurring during the slab CC process has heredity. In the casting direction, the concentration of solutes in the liquid pool increases gradually until the casting has solidified completely. After complete solidification, the solutes’ concentration maintains an almost constant value. On the centerline, the maximum segregation degree occurs at a position roughly 614 mm from the slab center. The maximum centerline segregation degrees of C, Si, Mn, P, and S solutes are 1.163, 1.058, 1.045, 1.111, and 1.165, respectively.

Architected materials are materials engineered to utilize their topological aspects to enhance the related physical and mechanical properties. With the witnessed progressive advancements in fabrication techniques, obstacles and challenges experienced in manufacturing geometrically complex architected materials are mitigated. Different strut-based architected lattice structures have been investigated for their topology-property relationship. However, the focus on lattice design has recently shifted toward structures with mathematically defined architectures. In this work, we investigate the architecture-property relationship associated with the possible configurations of employing the mathematically attained Schoen's I-WP (IWP) minimal surface to create lattice structures. Results of mechanical testing showed that sheet-based IWP lattice structures exhibit a stretching-dominated behavior with the highest structural efficiency as compared to other forms of strut-based and skeletal-based lattice structures. This study presents experimental and computational evidence of the robustness and suitability of sheet-based IWP structures for different engineering applications, where strong and lightweight materials with exceptional energy absorption capabilities are required.

Phenol red dyed bis thiourea cadmium acetate (BTCA) crystals of ∼30 × 10 × 6 mm dimension have been grown for the first time using the slow evaporation solution technique. Diffuse reflectance measurements show absorption bands at 363 and 563 nm in the doped crystal. Optical energy gap was calculated to be 4–5 eV. Photoluminescence spectra were recorded using 320 nm excitation source. The chemical etching study was done and etch pit density was found to be reduced from 4.5 × 103/cm2 (pure) to 3.0 × 102/cm2 (dyed). Mechanical strength is increased from 74.1 kg/mm2 for pure to 94.7 kg/mm2 for dyed crystals. The enriched properties of BTCA in the presence of dye suggest that the dyed crystals will be more applicable compared to pure crystals.

Unique SnO2 monoflowers with an aloe-like morphology were successfully synthesized via a one-step hydrothermal method. The structural, chemical, and physical characteristics were investigated. The results exhibited that the as-prepared sample was assembled by triangle rutile SnO2 nanoslices with rough surfaces. A possible crystal growth and nanostructure assembling mechanism was proposed. The Raman peaks in 171, 235, and 211 cm−1 proved that a large amount of oxygen defects existed inside the sample, which might narrow the band gap from 3.6 eV of pure SnO2 to 2.7 eV of the sample. The sensor fabricated by aloe-like SnO2 nanostructures exhibited an excellent response and selectivity to ethanol. The developed sensor can detect ethanol as low as 10 ppm at 360 °C. The prepared aloe-like SnO2 microflower sensor exhibited a gas sensing response of about 7.46 when exposed to 100 ppm of ethanol gas at 360 °C, which was probably related to more numerous defects and thinner structure of aloe-like SnO2.

In this research, heat transfer analysis was operated by simulation to investigate the influence of carbon nanotubes (CNTs) on laser absorption and molten pool characteristic as well as the vaporization porosity of a typical magnesium alloy of AZ31B in the selective laser melting (SLM) process. It is concluded that the laser absorption is enhanced by 7.9% through mixing 1.5 wt% CNTs into AZ31B alloy powders. The full melting state of molten pools for CNTs/AZ31B composites was achieved by laser input energy densities (LIEDs) larger than 42 J/mm3. However, vaporization porosity has an ascendent tendency with LIED increasing, which leads to poor densities of manufactured parts. As a result, the optimal relative density and mechanical properties of composites are obtained by an LIED of 42 J/mm3. It may solve the problem of low laser absorption in laser processing for magnesium alloys and provide a referenced method to evaluate the vaporization porosity of the material in the SLM process.

Designing advanced nonprecious metal electrocatalysts to reduce overpotential and accelerate hydrogen evolution reaction (HER) has attracted considerable attention. However, improving the sluggish kinetics for electrocatalytic HER in alkaline media is still a great challenge. Herein, we found that amorphous NiO nanoclusters directly grown on nickel foam (NiO/NF) as a bifunctional HER catalyst demonstrated an ultrahigh electrocatalytic activity in alkaline environment. Such excellent HER performance of NiO/NF might mainly originate from the exposed interfaces of metallic Ni and amorphous NiO. The coordinatively unsaturated amorphous NiO domain is propitious to the adsorption of water molecule and the successive cleavage of HO–H bond, while the neighboring metallic Ni domain is beneficial to the adsorption of resulting Hads intermediate and recombination into hydrogen molecules, thus expediting the HER toward lower overpotential. These findings may open a window to the design and preparation of earth-abundant, low-cost metal oxide/metal electrocatalysts with desirable HER activities.

High-voltage (≥4.0 V) operation of supercapacitor devices was demonstrated using carbon nanotubes as active electrode materials combined with room temperature ionic liquids as electrolyte. Pouch cells were assembled with four different ionic liquids, 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM-BF4), diethyl-N-methyl-N-(2-methoxyethyl) ammonium bis(trifluoromethanesulfonyl)imide (DEME-TFSI), diethyl-N-methyl-N-(2-methoxyethyl)ammonium tetrafluoroborate (DEME-BF4), and 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr14-TFSI). Cyclic voltammetry showed the maximum operational voltage to be 4.5 V for DEME-TFSI and 4.7 V for DEME-BF4. Compared to electric double layer capacitor (EDLC) cells using propylene carbonate electrolyte at 2.7 V, capacitance increased by 20% using BMIM-BF4 at 4.0 V, DEME-TFSI at 4.5 V, DEME-BF4 at 4.7 V, and Pyr14-TFSI at 4.3 V, with tripling of energy density and comparable power density using Pyr14-TFSI-based EDLCs. Long-term cyclability using BMIM-BF4 ionic liquid electrolyte operating at 4.0 V showed retention of >80% of initial capacitance after 65,000 continuous cycles without doubling of initial cell equivalent series resistance.

The basic principle of high-entropy alloys (HEAs) is that high mixing entropies of solid-solution phases enhance the phase stability, which renders us a new strategy on alloy design. The current research of HEAs mostly emphasizes mechanical behavior at room and higher temperatures. Relatively fewer papers are focused on low-temperature behaviors, below room temperature. However, based on the published papers, we can find that the low-temperature properties of HEAs are generally excellent. The great potential for cryogenic applications could be expected on HEAs. In this article, we summarized and discussed the mechanical behaviors and deformation mechanisms, as well as stacking-fault energies, of HEAs at low temperatures. The comparison of low-temperature properties of HEAs and conventional alloys will be provided. Future research directions will be suggested at the end.

Cobalt-doped ZnO (CZO) film nanocomposites have been deposited on Si(100) substrates by pulsed electron beam ablation from a single Co0.2Zn0.8O target. The films have been deposited at various electron beam repetition rates (1, 2, 4, and 8 Hz), under a background argon (Ar) pressure of ∼3 mtorr, an accelerating voltage of 16 kV, and a deposition temperature of 450 °C. The effect of beam frequency on the structural, chemical, and morphological properties of the films has been assessed. The findings reveal that film thickness, film roughness, and degree of crystallinity of the ZnO wurtzite structure increase with beam frequency, while globule size and density reach maximum and minimum values, respectively, as the beam frequency is increased. The pulse frequency does not appear to affect the average nanoparticulate size. X-ray photoelectron spectroscopy data support the co-existence of metallic cobalt (Co0), CoO, and Co2O3 in CZO films near the surface. Phase analysis by X-ray diffraction also confirms the presence of hexagonal close-packed metallic cobalt whose content in the films is practically unaffected by beam frequency.

This article focuses on the finite element modeling of toroidal microinductors, employing first-of-its-kind nanocomposite magnetic core material and superparamagnetic iron nanoparticles covalently cross-linked in an epoxy network. Energy loss mechanisms in existing inductor core materials are covered as well as discussions on how this novel core material eliminates them providing a path toward realizing these low form factor devices. Designs for both a 2 μH output and a 500 nH input microinductor are created via the model for a high-performance buck converter. Both modeled inductors have 50 wire turns, less than 1 cm3 form factors, less than 1 Ω AC resistance, and quality factors, Q’s, of 27 at 1 MHz. In addition, the output microinductor is calculated to have an average output power of 7 W and a power density of 3.9 kW/in3 by modeling with the 1st generation iron nanocomposite core material.