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Recent Advances in Piezoelectric Ceramics
Published in Lionel M. Levinson, Electronic Ceramics, 2020
Robert C. Pohanka, Paul L. Smith
Like other ceramics, piezoelectric materials, such as barium titanate and lead zirconate titanate fail in a brittle manner from pre-existing flaws, typically pores and pore clusters, machining-induced cracks, and inclusions. The presence of these small (typically 20-100 μm) defects in ceramics leads to the magnification of applied stresses at these sites.
Bio-Ceramics for Tissue Engineering
Published in Naznin Sultana, Sanchita Bandyopadhyay-Ghosh, Chin Fhong Soon, Tissue Engineering Strategies for Organ Regeneration, 2020
Hasan Zuhudi Abdullah, Te Chuan Lee, Maizlinda Izwana Idris, Mohamad Ali Selimin
Gel oxidation is a surface modification of titanium (Ti) by using thermochemical method to prepare bioactive ceramic (TiO2) (Kim et al. 1996). The bioactive ceramic layer formed on the Ti substrate is important to improve tissue compatibility and natural bonding between the implant and the living bone (Han and Xu 2004). Gel oxidation can be explained as a two-steps process: Gelation: Sodium titanate formed on Ti substrate after treating with NaOH aqueous in glass bottle (24 hours, at 60°C) as illustrated in Fig. 8.2 (Kim et al. 1996, Abdullah 2010). Various concentrations of NaOH were used to vary the thickness of sodium titanate hydrogel.Oxidation: Treated Ti oxidised by heat treatment to produce titanium dioxide (TiO2) and stabilise the sodium titanate. Amorphous sodium titanate was produced at low temperature (< 600°C) or a mixture of crystalline sodium titanate and titanium dioxide produced at high temperature (≥ 600°C) due to dehydration and densification of the gel (Kim et al. 1996, Jonášová et al. 2004).
Electroactive Polymers and Their Carbon Nanocomposites for Energy Harvesting
Published in Inamuddin, Mohd Imran Ahamed, Rajender Boddula, Tariq Altalhi, Nanogenerators, 2023
B.T.S. Ramanujam, Reshma Haridass, Pranesh Muralidharan, Ashok Kumar Nanjundan, Deepak Dubal, Pratheep K. Annamalai
The global energy demand is constantly increasing due to the growing population and emerging advancements in technologies and is estimated to rise by 50% in the year 2050 [1]. On the other hand, the depletion of conventional sources of energy like fossil fuels, coal, etc., has raised alarms. Hence, there is a need to invest in clean energy technologies. In this regard, the use of advanced materials for energy harvesting and energy storage applications is explored as the probable solution to address the hiking energy demands. Recently, advanced functional materials have been synthesized to design and fabricate new devices or technological products that can harvest energies from light, heat, vibrations, the flow of fluids, etc. This is achieved through designing devices to convert ambient energies in the form of utilizable electrical power through piezoelectric, thermoelectric, and pyroelectric effects. In such applications, the choice of the material plays a crucial role in determining the efficiency of energy harvesting devices. Conventional piezoceramics such as barium titanate and lead zirconate titanate are less ductile and tend to crack. Furthermore, the processing of those ceramic materials in the form of a thin film increases the cost. Hence, electroactive polymers (EAPs) and polymer nanocomposites, which are flexible, easily processible, and cost-effective, have become the focus of intense research [2]. Energy harvesting can be effectively achieved using EAPs by enhancing their properties such as piezoelectricity [3], electrical conductivity [4], etc. For the development of smart, portable, and wearable electronics, harnessing energy from nonconventional sources using EAPs has become a preferable option to provide an extended life for the energy harvester [5].
Encapsulation of Sr-loaded titanate spent adsorbents in potassium aluminosilicate geopolymer
Published in Journal of Nuclear Science and Technology, 2020
Natatsawas Soonthornwiphat, Yutaro Kobayashi, Kanako Toda, Kazuma Kuroda, Chaerun Raudhatul Islam, Tsubasa Otake, Yogarajah Elakneswaran, John L. Provis, Tsutomu Sato
The titanate adsorbent is an inorganic ion exchanger which has a layered structure of titanium-oxygen octahedral sheets. Between the sheet layers there is sodium which forms a hydrous sodium titanate structure [18,21]. These sodium ions are readily exchangeable, and the layered structure gives a large surface area with the high amount of interlayer water and relatively open layered structure. These characteristics support the efficiency of the ion exchange reaction between Na+ and other more-preferred cations [2–4,22,23]. The Sr2+ has a higher valence than that of Na+, and the substitution of multivalent for monovalent cations will decrease the number of ions between the interlayer of the titanate sheets and will lead to a shrinking of the layer spacing making the layered structure more stable [3,24–29]. These characteristics make the adsorption of Sr2+ on titanate adsorbents highly selective when compared to alkali metal ions, almost all of the Sr2+ exchangeable with Na+ in the sorbent with remaining Na+ mainly left on the titanate adsorbent as expressed in Equation (1).