Papers by Keyword: Chemical Reactivity

Abstract: Biodiesel B40, a blend of 40% biodiesel and 60% diesel, has become a focal point in Indonesia’s clean energy transition. The potential for emission reductions, sustainable resource utilization, and the opportunity for integrating nanoparticle- and oxygenate-based additive technologies make B40 a promising alternative fuel. However, the chemical nature of the unsaturated ester compounds in B40 presents new challenges in the formation of NOx emissions and oxidative stability. This review aims to summarize the latest research on the molecular structure, combustion reactivity, and engine performance optimization strategies when using B40. Emphasis is placed on additives such as CeO₂, phenolic antioxidants, and short-chain oxygenates that enhance thermal efficiency and mitigate emissions. Through analysis from molecular perspectives to energy policy, this review highlights comparative trade-offs, industrial scalability, and research gaps. The paper also recommends standardized testing, hybrid additive approaches, and techno-economic assessments to accelerate the industrial deployment of B40.

Abstract: Chemical reactivity and cathode properties of LaCoO₃ were investigated using new oxide ion conductor, lanthanum silicate oxyapatite. The LaCoO₃ is found to be good candidate for cathode of the lanthanum silicate oxyapatite solid-electrolyte since no chemical reaction occurred between the LaCoO₃ and lanthanum silicate oxyapatite heating at 1273 K for 60 h in air. Based on electrochemical measurements, lower overpotential between the LaCoO₃ and lanthanum silicate oxyapatite was confirmed compared to the overpotential at YSZ/LaCoO₃ interface. From analysis on the extended interfacial conductivity as function of oxygen activity at the triple phase boundary at fixed temperature, the overpotential evaluated by impedance spectra is the rate limiting process by oxygen diffusion on the LaCoO₃ surface. Comparing to the bulk conductivity of LaCoO₃, the electrode resistance evaluated by impedance spectra was confirmed to be different from the electrical transport properties of the LaCoO₃ bulk.

Abstract: Relationship between the chemical reactivity and the orientation of SiC substrates was investigated. Thermal etching of 4H-SiC in the mixed gas of oxygen and chlorine was carried out as the chemical reaction. The etching rate did not change monotonously with the increase of the off angle in 4H-SiC (000-1) C substrate. By the use of such tendency in the thermal etching, the three dimensional structure with the specific pyramidal plane was able to be obtained.

Abstract: The phase transformation kinetics on cooling and resulting microstructures of steel-based matrix composites (MMC) reinforced with TiC particles by powder metallurgy were studied. In addition, the phase transformation kinetics of the MMC were compared to those of the same steel without TiC and consolidated in the same conditions. The presence of TiC particles strongly favors the diffusive transformations in the steel matrix of the MMC. Different complementary techniques (XRD, SEM, TEM/EDX, atom probe tomography, in situ synchrotron XRD) were performed to analyze the chemical reactivity between TiC particles and the steel powders occurring during consolidation process and further heat treatments. Composition changes in the TiC as well as in the matrix were characterized. The chemical composition after treatment in the TiC particles tends toward the thermodynamic calculations with ThermoCalc. The effect of changes in chemical composition and the role of TiC particles acting as new favorable nucleation sites are discussed in regards to the obtained results.

Abstract: This work is focused on the bioactive glasses obtained by melting and rapid quenching. Two glasses with mineral composition of: 47% SiO2 - 26% CaO - 21% Na2O - 6% P2O5 and 48% SiO2 - 30% CaO - 18% Na2O - 4% P2O5 were investigated. The aim of this study was to establish the kinetics of HCAp layer formation “in vitro” and to control the adhesion and proliferation cells of the two glasses in contact with osseous cells. Obtained results permit to evaluate their chemical reactivity and their bioactivity after immersion in the SBF-K9. Ionic exchanges between biomaterials and SBF liquid during the “in vitro” experiments highlight the differences of the chemical reactivity and bioactivity of 47S6 and 48S4. The structural basis for the effect of cristallinity on the rates of HCA formation in vitro in favour of glasses was also established. The melt derived 47S6 and 48S4 glasses offer to surgeons new compositions with different bioactivity kinetic that bioglassÒ 45S6 and can be adaptable in some other bony pathology.

Abstract: Due to the ultrafine grains (or domains or particles) and a high density of grain boundaries (or generally interfaces) in nanostructured materials, many properties and performance of the materials are expected to be significantly varied with respect to their coarse-grained counterparts. Extensive investigations over the past decays indicated that the nanostructured metals do possess some novel properties that may find technological applications in industry. In this talk, a brief survey of current status of investigations on properties of nanostructured metals will be summarized with emphasis on the following properties.