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In the future, when fossil fuels are exhausted, alternative energy sources will be essential for everyday needs. Hydrogen-based energy can play a vital role in this aspect. This energy is green, clean, and renewable. Electrochemical hydrogen devices have been used extensively in nuclear power plants to manage hydrogen-based renewable fuel. Doped zirconate materials are commonly used as an electrolyte in these electrochemical devices. These materials have excellent physical stability and high proton transport numbers, which make them suitable for multiple applications. Doping enhances the physical and electronic properties of zirconate materials and makes them ideal for practical applications. This review highlights the applications of zirconate-based proton-conducting materials in electrochemical cells, particularly in tritium monitors, tritium recovery, hydrogen sensors, and hydrogen pump systems. The central section of this review summarizes recent investigations and provides a comprehensive insight into the various doping schemes, experimental setup, instrumentation, optimum operating conditions, morphology, composition, and performance of zirconate electrolyte materials. In addition, different challenges that are hindering zirconate materials from achieving their full potential in electrochemical hydrogen devices are discussed. Finally, this paper lays out a few pathways for aspirants who wish to undertake research in this field.

The three-dimensional (3D) ultrafine fibrous scaffolds loaded with functional components can not only provide support to 3D tissue repair, but also deliver the components in-situ with small dosage and low fusion frequency. However, the conventional loading methods possess drawbacks such as low loading capacity or high burst release. In this research, an ultralow concentration phase separation (ULCPS) technique was developed to form 3D ultrafine gelatin fibers and, meanwhile, load an anti-inflammatory drug, diclofenac, with high capacities for the long-term delivery. The developed scaffolds could achieve a maximum drug loading capacity of 12 wt.% and a highest drug loading efficiency of 84% while maintaining their 3D ultrafine fibrous structure with high specific pore volumes from 227.9 to 237.19 cm3/mg. The initial release at the first hour could be reduced from 34.7% to 42.2%, and a sustained linear release profile was observed with a rate of about 1% per day in the following 30 days. The diclofenac loaded in and released from the ULCPS scaffolds could keep its therapeutic molecular structure. The cell viability has not been affected by the release of drug when the loading was less than 12 wt.%. The results proved the possibility to develop various 3D ultrafine fibrous scaffolds, which can supply functional components in-situ with a long-term.

Fiber reinforced polymer composite (FRPC) materials are superior to other conventional materials because of their high strength to weight ratio, corrosion resistance, and moisture resistance. FRPC materials are preferred in many high-end applications such as marine, automobile, aerospace, and advanced sporting goods. The aim of this study was to investigate the in-plane quasi-static compressive and durability studies of nanophased FRPC materials. Composite samples were fabricated using unmodified epoxy and epoxy modified with montmorillonite nanoclay (MMT), graphene nanoplatelets (GNP), and a combination of the two as a binary reinforcement with carbon fibers. Quasi-static compression tests were conducted for mechanical property evaluation. Seawater conditioning was performed for a six-month period both at room and arctic cold temperatures. The results indicated that addition of GNP and MMT improved the compressive properties of carbon/epoxy composites compared to unmodified carbon samples. Specific compressive strength and modulus of GNP infused samples improved by 30 and 41% respectively; the samples showed a relatively higher strain to failure than the unmodified samples. Specific compressive strength and modulus increased by 32 and 47%, respectively, for carbon/epoxy samples with MMT reinforcement. Performance of hybrid carbon/ glass/epoxy composites was lower compared to other FRPC materials considered in the study. The mode of failure of fractured samples investigated using scanning electron microscopy (SEM) showed a rough morphology after incorporation of nanoparticles into the polymer matrix. This is indicative of enhanced interfacial bonding between carbon/epoxy and the nanoparticles.

It is evident from the study that transboundary traveling has a significant effect on air quality and the pollutants traveled firmly beyond the boundary line of Bangladesh.

Phase separation is one of the most important technologies to fabricate ultrafine fibers. Different from electrospinning, phase separation can produce fibers arranged in three dimension and thus has unique advantages, such as mimicking the fibrous structure in extracellular matrix more closely. However, to precisely control the architectures of phase separated scaffolds is challenging. This chapter introduces the current understanding about the mechanisms of phase separation and summarizes the factors, which can control the morphologies of resultant scaffolds. Methods to produce fibrous phase separated scaffolds are discussed in this chapter. Applications and limitations are also analyzed.

Solder joints in electronic packages are frequently exposed to thermal cycling environment. Such exposures can occur in real life application as well as in accelerated thermal cycling tests used for the fatigue behavior characterization. Because of temperature variations and CTE mismatches of the assembly materials, cyclic temperature leads to damage accumulation and material property evolution in the solder joints. This eventually results in crack initiation, and subsequent crack growth and failure. In this study, the nanoindentation technique was used to understand the evolution of mechanical properties (modulus, hardness and creep behavior) of SAC305 BGA solder joints and Cu pad subjected to thermal cycling loading for various durations. In addition, microstructural changes in those joints that occur during thermal cycling were observed using both SEM and optical microscopy. BGA solder joint strip specimens were first prepared by cross sectioning BGA assemblies followed by surface polishing to facilitate SEM imaging and nanoindentation testing. The strip specimens were chosen to contain several single grain solder joints. This enabled large regions of solder material with equivalent mechanical behavior, which could then be indented several times after various durations of cycling. After preparation, the solder joint strip samples were thermally cycled from T = −40 to 125 °C in an environmental chamber. At various points in the cycling (e.g. after 0, 50, 100, and 250 cycles), the package was taken out from the chamber, and nanoindentation was performed on each single grain joint and joint Cu pads to obtain the modulus, hardness, and creep behavior at 25 °C. This allowed the evolution of the mechanical properties with the duration of thermal cycling to be determined. Moreover, microstructural changes were also observed after various durations of cycling using optical microscopy. From the nanoindentation test results, it was found that the modulus and hardness of the SAC305 solder joints dropped significantly with thermal cycling. However, the Cu pad did not show any change in the mechanical behavior during cycling. Moreover, the nanoindentation creep test results showed significant increases in the creep deformation for solder joints whereas Cu pad did now show any significant changes in creep behavior when both of them were subjected to thermal cycling up to 250 cycles.

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