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The overmolding of short fiber reinforced polymer compounds onto continuous fiber reinforced composite substrates provides design flexibility and the ability to tailor stiffness, strength, and damage tolerance for structural applications. In this work, a novel molding approach that enhances the bonding strength by mechanical interlocking is presented. The effectiveness of the proposed approach was validated by characterization of the bonding strength between a short glass fiber PP (SGFPP) composite overmolded onto a continuous glass fiber reinforced PP (CGFRPP) prepreg. Enhancement of the bonding strength was achieved by judiciously drilling tapered holes on the CGFRPP substrate before molding, which facilitated better interlocking with the injection molded SGFPP composite. The overmolding of preheated composites with tapered holes yielded up to 60% improvement in bonding strength. In general, having multiple holes helped improve bonding up to certain hole diameter. Similarly, preheating of the substrate over a short time improved the interfacial adhesion, while extended preheating resulted in a reduction of bonding quality. SEM analysis of the fracture surfaces after the tensile debonding test revealed that the SGFPP filled the holes on the substrate during overmolding. KEYWORDS bonding strength, injection molding, mechanical properties, short-fiber composites, 1 | INTRODUCTION One of the primary goals of the automotive industry is to reduce carbon dioxide emissions via decreasing vehicle weight to meet the new regulations of Euro 7 [...]

Osteoarthritis (OA) is a prevalent joint disorder characterized by cartilage and bone degradation. Medical therapies like glucosaminoglycan (GAG), chondroitin sulfate (CS), and hyaluronic acid (HA) aim to preserve joint function and reduce inflammation but may cause side effects when administered orally or via injection. Microneedle arrays (MNAs) offer a localized drug delivery method that reduces side effects. Thus, this study aims to demonstrate the feasibility of delivering GAG, CS, and HA using microneedles in vitro. An optimal needle geometry is crucial for the successful application of MNA. To address this, here we employ a multi-objective optimization framework using the non-dominated sorting genetic algorithm II (NSGA-II) to determine the ideal MNA design, focusing on preventing needle failure. Then, a three-step fabrication approach is followed to fabricate the MNAs. First, the master (male) molds are fabricated from poly(methyl methacrylate) using mechanical micromachining based on optimized needle geometry. Second, a micro-molding with Polydimethylsiloxane (PDMS) is used for the fabrication of production (female) molds. In the last step, the MNAs were fabricated by microcasting the hydrogels using the production molds. Light microscopy (LIMI) confirms the accuracy of the MNAs manufactured, and in vitro skin insertion tests demonstrate failure-free needle insertion. Subsequently, we confirmed the biocompatibility of MNAs by evaluating their impact on the L929 fibroblast cell line, human chondrocytes, and osteoblasts. [ABSTRACT FROM AUTHOR]

Mo-Ni-B-Al as-cast alloys containing 35.5-58.7 wt% Mo, 23.0-57.6 wt% Ni, 3.3-5.2 wt% B, and 2.2-13.5 wt% Al were synthesized by Self-Propagating High-Temperature Synthesis (SHS) using a mixture of MoO3, NiO, B2O3 and Al powders in order to obtain low-cost Mo2 NiB2 containing hard materials. The first series of experiments were performed using 1.05 times the stoichiometric amount of Al. In the second series of experiments, FactSage thermochemical modeling software was used to minimize Al increasing the Mo2NiB2 formation in the as-cast alloys. The products were characterized by using atomic absorption spectrometry (AAS), X-ray diffraction (XRD), scanning electron microscopy (SEM) and micro-hardness techniques.

To lower solid oxide fuel cell operating temperatures down to ≤ 700°C, we fabricated La0.8Sr0.2MnO3–Bi1.44Y0.56O3 (LSM-YDB) cathode films from a "single-pot" mixture of polymeric LSM and YDB precursors, which yielded nanocomposite-structured films with long triple phase boundary lengths. Alternating nanolayers of LSM and YDB phases were revealed by STEM-EDS analysis. The microstructure forming at 600°C contained YDB nanoparticles in the LSM phase and LSM nanoparticles in the YDB phase, ensuring 3-D interconnectivity for each phase and a percolation pathway. An area specific polarization resistance of 0.55 cm2 was measured at 600°C. [ABSTRACT FROM AUTHOR]

This study concerns the substitution of copper for nickel in the Ni–Ti system in order to obtain a molar ratio of Ni40Ti50Cu10. Effects of preheating temperature were studied to understand the morphology, phase transformation, and microstructure of the samples by using self-propagating high-temperature synthesis. Therefore, three distinct preheating temperatures (230 °C, 320 °C, and 410 °C) were used for the study. The thermochemical calculations performed with FactSage presented similar results with the experimental data in terms of solid–liquid ratios and adiabatic temperature during the reactions. An increase in the preheating temperature very slightly changed the transformation temperature, but it was shown to be insignificant. B2 crystal structure was found as the main phase besides a small amount of martensite, Ti2Ni(Cu), and Ni(Cu)2Ti–Ni(Cu)3Ti by various characterization methods. The monoclinic twinned martensitic (B19′) structure was encountered in transmission electron microscopy analyses. [ABSTRACT FROM AUTHOR]