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This research presents a novel approach to overcome the stress shielding effect and non-degradability commonly observed in metallic implants, which often require revision surgery. The study introduces a hybrid metal/ceramic (Ti/HA) reinforcement within the Mg-3Zn binary alloy matrix fabricated using the squeeze casting technique. The alloy matrix incorporates 1 wt% Ti and varying weight percentages (0.5, 1, and 1.5 wt%) of hydroxyapatite (HA). Microstructure analysis revealed significant grain refinement in the alloy upon adding the hybrid reinforcement. Phase analysis using XRD confirmed the presence of Mg-Zn intermetallic phases and corresponding reinforcement phases. Vickers microhardness testing demonstrated a 14.4% (89 HV) increase in hardness for the hybrid composite with 1Ti/1.5HA compared to the unreinforced alloy and other composites. Compressive testing revealed enhanced mechanical properties in the hybrid composites. The 1Ti/1.5 HA hybrid composite displayed a 12% (121 MPa) increase in compressive yield strength (CYS) compared to the alloy, while the 1Ti/1HA hybrid composite exhibited an impressive 22.5% (217 MPa) increment in compressive strength. Corrosion performance evaluation in a phosphate-buffered saline (PBS) environment indicated that the 1Ti/1.5 HA hybrid composites demonstrated comparable corrosion performance to the unreinforced alloy, with a corrosion density of 4.53 × 10−5μA/cm2and a linear polarization resistance of 893 ohms. Based on the findings, the Mg-3Zn alloy with 1Ti/1.5 HA hybrid reinforcement emerges as a promising material for load-bearing biodegradable implants.

This research addresses the demand for biodegradable orthopedic implants by enhancing magnesium-based alloys. Biodegradable magnesium alloy-based hybrid composites, produced through squeeze casting, incorporate titanium (Ti) and hydroxyapatite (HA) particles to improve microstructure, hardness, and compressive strength. The Mg–3Zn/1Ti/1.5HA composite exhibits a 13% increase in hardness and a 15.8% enhancement in compression strength compared to the base MZA alloy. In corrosion assessments at 216 h, MZA/1Ti/1.5HA shows a 21% lower corrosion rate than MZA/1Ti/0.5HA and a 10% lower rate than MZA/1Ti/1HA. The refined grain structure and formation of protective oxide layers resulting from Ti and HA incorporation contribute to enhanced corrosion resistance. Cytotoxicity assessments reveal excellent biocompatibility, with the Mg–3Zn/1Ti/1.5HA composite exceeding an 80% relative growth rate due to the formation of bone-like apatite layer, surpassing MZA/1Ti/0.5HA and MZA/1Ti/1HA. These findings underscore the potential of squeeze-casted magnesium alloy-based hybrid composites, particularly Mg–3Zn/1Ti/1.5HA, as promising orthopedic implant biomaterials.

This study examines the tribological effects of a new titanium/hydroxyapatite (Ti/HA) hybrid reinforcement in the Mg–3Zn alloy matrix. Stir-aided squeeze casting was used to develop the hybrid composites. The density, microhardness, and microstructure of the composites were analysed using optical microscopy and SEM. A tribological study was conducted using a pin-on-disc tribology meter with phosphate-buffered saline as the lubricant medium under various loading conditions (15, 30, and 45 N). Results showed that the inclusion of Ti/HA hybrid particles increased the microhardness of the hybrid composites by 14% compared to the base alloy matrix. Microstructural characterization studies showed a better distribution of reinforced particles and refined grain size. SEM analysis revealed the presence of α-Mg and β-Mg–Zn phases. Wear test results indicated that the introduction of 1%Ti and 1.5%HA hybrid particles in the Mg–3Zn alloy matrix enhanced wear resistance and lowered COF under various wear testing conditions. SEM characterizations of worn surface showed that abrasive wear, oxidation, delamination, and severe delamination wear mechanisms occurred during wear test. Moreover, abrasive wear acted as a wear initiator and occurred along with all other wear mechanisms.

Huge quantities of chrome-tanned leather wastes are produced every year from leather, footwear and clothing related industries. Many attempts have been made to reuse them in the form of boards, sheets, composites, etc. However, most of those methods have deficiencies such as low flexibility, cost effectiveness, non-eco-friendly, stringent process control and unacceptable properties. Our current work relies on an alternate method of reusing these wastes to form composite sheets with desirable characteristics. The waste chrome shavings were partially hydrolyzed and made into composite sheets using an eco-friendly polydimethylsiloxane (PDMS) polymer. The sheets were characterized for their mechanical, thermal and morphological properties. The tensile and thermal properties of composite sheets increase gradually upon increase in PDMS concentration up to 20 wt.% followed by an abrupt decrease when the PDMS concentration increased further to 30 and 40 wt.%. The softness of sheets has an inverse relationship with tensile stress and directly proportional to the elongation values. Fourier-transformed infrared (FTIR) analysis of composite sheets revealed the presence of dominant peaks corresponding to amide bands of collagen as well as characteristic bands of PDMS, showing the homogeneity of the developed composite sheets. Thus the developed composite sheets demonstrate potential for numerous applications in footwear, clothing and related industries.

Lack of availability of good quality leather and growing demand for products force the researchers to find alternative materials or to partially substitute the usage of leather in products. Eco-friendly biodegradable materials are the need of the hour owing to growing environmental issues associated with the synthetic polymers. This study aims at assessing the physical, comfort, structural and thermal properties of non-mulberry silks such as eri, muga and a blend of eri and muga (EM) fabrics for their suitability to combine with goat suede leather for apparel application. It was found that all the selected fabrics exhibit comparable or even better comfort and mechanical properties to that of goat suede leather. Indeed tensile strength of muga fabric is much superior to goat suede leather. On the other hand, goat suede leather dominates in percentage elongation compared to all the selected fabrics. Scanning electron microscopy and FT-IR spectroscopic analysis provide convincing evidences on the fact that all the selected silk fabrics are based on non-mulberry varieties. The thermal stability of all the three silk fabrics is better than goat suede leather. The results of this study suggest that the selected silk fabrics can be used for making apparel as well as other variety of products in combination with leather.

The reduction of AuCl4^- to colloidal gold in the presence of aliphatic alcohols and sodium dodecyl sulfate in aqueous solutions using 20 kHz ultrasound is described. The extent of reduction of AuCl4^- was found to be directly dependent on the gas−solution interfacial activity of the solutes used. The diameters of the gold colloids produced were in the size range of 9−25 nm. The particle size was dependent on the alcohol concentration in solution and on the hydrophobicity of the alcohol. For a particular alcohol concentration, smaller particles were obtained the greater the hydrophobicity of the alcohol. A detailed mechanism is presented that describes the overall sonochemically initiated reduction of AuCl4^- leading to the formation of colloidal gold.

The influence of aliphatic alcohols, sodium dodecyl sulfate and sodium chloride on the intensity of sonoluminescence (SL) generated by 3.5-ms pulses of 20-kHz and 515-kHz ultrasound in air-saturated aqueous solutions has been examined. The water-soluble solutes were found to affect the SL quite differently at the two frequencies when applied at approximately the same range of power. At 20 kHz, the solutes had only a small effect on the SL signal generated, whereas at 515 kHz, the effect observed depended strongly on the specific solute present in solution. The contrasting results obtained at the two ultrasound frequencies have been interpreted in terms of transient bubbles giving rise to the SL at 20 kHz and repetitive transient bubbles producing the SL at 515 kHz.

The ultrasound (363 kHz) induced decomposition of a commercially available polydisperse nonylphenol ethoxylate surfactant (Teric GN9) has been investigated. The initial rate of decomposition was found to be a function of the monomer concentration of the surfactant below and above the critical micelle concentration. Based on HPLC, TOC, GC, and sonoluminescence quenching measurements, we conclude that the initial pathway for the decomposition of the Teric GN9 occurs via a combination of thermal breakdown and radical attack on surfactant molecules adsorbed at the surface of cavitating bubbles. Nearly 90% mineralization and/or degradation into volatile products of the surfactant was achieved after sonication for 24 h.

Low concentrations of short chain aliphatic alcohols and organic acids and bases suppress single-bubble sonoluminescence (SBSL) in water. The degree of SL quenching increases with the length of the aliphatic end of the alcohol, and is related to the concentration of the alcohol at the bubble/water interface. The light is preferentially quenched in the shorter wavelength region of the spectrum. Radius−time measurements of the bubble are not dramatically affected by the low levels of alcohol used. Butyric acid and propylamine behave in the same manner, but only in their neutral forms, indicating that the SBSL suppression is due to processes occurring within the bubble.

Multibubble sonoluminescence from water was found to be quenched by the addition of low levels of unsubstituted or 2-chloro-substituted aliphatic carboxylic acids and the aromatic solutes, phenol and aniline. In all cases, the sonoluminescence intensity could be restored to the level obtained in pure water by adjusting the solution pH to a point where the solutes were completely in their ionized form. A comparison of the sonochemical decomposition of phenol at pH levels above and below its pKa revealed that only when the solute was in its neutral form was there significant decomposition. It is shown that both the sonochemical decomposition of phenol and the sonoluminescence quenching by all solutes studied can be directly correlated with the amount of solute adsorbed at the bubble/solution interface. The relationship between sonochemical activity and sonoluminescence quenching by water-soluble organic solutes is discussed.

The 515 kHz ultrasound-initiated reduction of AuCl4^- to Au(0) was examined as a function of the concentration of various surface-active solutes. The amount of AuCl4^- reduced in the presence of ethanol, propan-1-ol, and butan-1-ol was found to be dependent on the surface excess of the alcohol at the gas/solution interface, i.e., the relative concentration of the alcohol at the gas/solution interface compared to the bulk solution concentration. The efficiency of reduction of AuCl4^- in the presence of the surfactants sodium dodecyl sulfate or octaethylene glycol monodecyl ether was found to be related to the monomer concentration of the surfactant in solution. The light emitted (sonoluminescence) during ultrasonic irradiation of the aqueous solutions was also monitored and compared with the trends observed in the sonochemical experiments. The sonoluminescence was observed to be significantly reduced in the presence of alcohol, and the effect was correlated with the surface excess of the alcohols at the gas/solution interface. In contrast, the effect of the surfactants on the sonoluminescence was highly dependent on concentration and headgroup type of the surfactant.

Abstract: WO3 semiconductor particles, useful in solar energy conversion processes, were doped with transition metal ions, Ti(III), V(IV), Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Ru(III) by a high-temperature sintering technique. The method of preparation of these photocatalysts is described in detail. The structural changes effected during sintering were investigated by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The XRD analysis indicated that the monoclinic crystal structure of WO3 was not altered during sintering. SEM studies showed that the sizes of the particles ranged from 1 to 10 μm and the crystallinity was increased due to doping. The dopants were found to be mostly distributed on the surface of WO3 particles.

The sonoluminescence generated in water with pulsed 515 kHz ultrasound has been studied in the presence of different chain length (C1−C5) aliphatic alcohols and the surfactants sodium dodecyl sulfate (SDS), dodecyltrimethylammonium chloride (DTAC), and N-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (DAPS). The ultrasound pulse widths used ranged from 1 to 10 ms, with duty cycles (on/off ratios) of 1:3 to 1:9. It was found that the sonoluminescence from the initial pulses was very low but increased in intensity and reached a maximum after 20−50 pulses, for all systems studied, depending on the pulse width and duty cycle. In the presence of alcohol the maximum signal decreased with increasing alcohol concentration, and the signal decline was more pronounced with increasing chain length of the alcohol. A good correlation was found to exist between the decline in the sonoluminescence signal and the Gibbs surface excess of the alcohol at the air/water interface. In the presence of SDS (an anionic surfactant) and DTAC (a cationic surfactant), quite different behavior was observed. At low concentrations of these two surfactants the maximum signal was significantly enhanced over that obtained in pure water, reaching a maximum at about 1 mM of surfactant. At higher concentrations the signal decreased again reaching a limiting value similar to that obtained in pure water. The sonoluminescence signal in DAPS (a zwitterionic surfactant) solutions remained much the same as in pure water. On the addition of 0.1 M NaCl to the three different types of surfactant solutions, the intensities of the emission signals obtained were essentially the same as in pure water. Possible mechanisms responsible for the different behavior in the sonoluminescence signal in the presence of the alcohols and surfactants are discussed.

RuS2 nanocrystallites were synthesized using a new technique, namely prolonged bubbling of H2S through a solution of RuCl3 in sulfolane and water at high temperatures. Optically transparent RuS2 colloidal particles could also be synthesized in hot sulfolane. Optical measurements of the RuS2 colloidal suspensions and powders showed a broad absorption in the visible spectral region, suggesting the suitability of this material for semiconductor sensitization experiments. The observed X-ray diffraction (XRD) data of the synthesized powder samples were in good agreement with the reported ASTM pattern of RuS2, confirming that RuS2 was the prepared compound by this new preparation technique. Scanning electron microscopic (SEM) pictures showed submicrometre sized crystallites. Heat treated powders of water prepared RuS2 showed < 50 nm particle sizes, and still smaller sizes were observed for the sulfolane prepared sample. Energy dispersive X-ray (EDX) analysis and X-ray fluorescence (XRF) measurements showed an Ru/S ratio of ~ 1:2 and also supported the XRD results.

Nowadays, the utilization of magnesium (Mg) alloys is increased due to its various beneficial characters such as better thermal conductivity, minimum density, less weight, superior strength, good dimensional, stability nature, etc. They are used in both mechanical as well as electrical industries. In the same way, it is used in electronic industries for its perfect capability of damping and electromagnetic shielding offers noise reduction. Although, they have a lot of advantages some disadvantages surround them. Mg alloy easily corroded when used at certain wet zones and the poor wear behavior may suppress the service life of Mg alloys. To overcome such issues, a surface coating approach is to be carried out on Mg alloy AZ91D using stellite powder to assist with NiCr pre-coating. The coated Mg alloys are studied for their porosity (%), corrosion rate (mm/year), and wear loss (mg). The experimental study is planned by Response Surface Methodology (RSM) using Box Behnken Design (BBD). The outcomes are validated by Hybrid Deep Belief Network (DBN) based Mayfly optimization approach in MATLAB version 2020a. The minimum porosity, corrosion rate and wear loss obtained for the coated AZ91D Mg alloy is 0.588%, 1.302 mm/year, and 0.719mg. Besides, the hybrid DBN-based predicted outcomes are closer to the experimental outcomes.

Irradiated (λ ≥ 410 nm) aqueous suspensions of RuO2‐doped WO3powders are found to decompose HSO5‐(I) efficiently.