Annealing Effect on the Ionic Conductivity of La0.6-.xLi3xTiO3 Made by Double Mechanical Alloying Method

Perovskite La2/3.xLi3xTiO3 with x = 0.11 （called LLTO11） powders were prepared by double mechanical alloying method from TiO2 （99.99%）, Li2CO3, （99.99%） and La203 （99.9%） powders, in ideal cation stoichiometry for La2/3_xLi3xTiO3. The obtained single phase of LLTO11 powder was isostatically pressed under a pressure of 450 MPa and annealed at a temperature ranging from 1,100 ℃ to 1,250 ℃. Optimal morphology and grain structure for the ionic conductivity of the samples were achieved at annealing temperature of 1,200 ℃. For this ceramic, the lithium ionic grains and grain-boundaries conductivities at room temperature possess a value of 1.5 × 10-3 S/cm and 4.8 × 10-5 S/cm, respectively. The improvement in the grain-boundaries conductivity was explained due to the decrease of the number of grains, included grain boundaries and the diminution of the pores in LLTO samples annealed at 1,200 ℃. The obtained results suggest useful applications of Lai2/3）.xLi3xTiO3 （x = 0.11） ceramics for the production of the solid state electrolytes, for high-temperature Li-ionic batteries, in particular.     

Human Action Recognition Based on 3D Human Modeling and Cyclic HMMs

Human action recognition is used in areas such as surveillance, entertainment, and healthcare. This paper proposes a system to recognize both single and continuous human actions from monocular video sequences, based on 3D human modeling and cyclic hidden Markov models (CHMMs). First, for each frame in a monocular video sequence, the 3D coordinates of joints belonging to a human object, through actions of multiple cycles, are extracted using 3D human modeling techniques. The 3D coordinates are then converted into a set of geometrical relational features (GRFs) for dimensionality reduction and discrimination increase. For further dimensionality reduction, k‐means clustering is applied to the GRFs to generate clustered feature vectors. These vectors are used to train CHMMs separately for different types of actions, based on the Baum–Welch re‐estimation algorithm. For recognition of continuous actions that are concatenated from several distinct types of actions, a designed graphical model is used to systematically concatenate different separately trained CHMMs. The experimental results show the effective performance of our proposed system in both single and continuous action recognition problems.     

Urea mediated synthesis of Ni(OH)2 nanowires and their conversion into NiO nanostructure for hydrogen gas-sensing application

Synthesis of low cost, scalable, robust, and multifunctional nanomaterials for gas sensing application has been received increasing interest in recent years. Herein, we introduce the urea mediated synthesis of Ni(OH)₂ nanowires and their conversion into NiO nanostructure for hydrogen gas-sensing application. The Ni(OH)₂ nanowires were synthesized by a facile hydrothermal method, where the urea concentration was adjusted to get desired nanowire morphology. Conversion of Ni(OH)₂ nanowires into single phase NiO was done by heat treatment of the as-synthesized product at temperature of 500 °C for 2 h. The morphology, crystal structure, crystallinity, and phase transformation of the products were examined by SEM, HRTEM, XRD, and XPS. Gas sensing properties were measured to various H₂ concentrations ranging from 50 ppm to 1000 ppm at different temperatures. Results show that the synthesized NiO nanostructure can be used to detect H₂ gas at the low concentrations ranging from 50 ppm to 1000 ppm. The sensor also showed good selectivity to CO, NH₃ and CO₂ gases.     

Partial oxidation of diesel fuel by plasma – Kinetic aspects of the reaction

Plasma reforming of fuel has recently been studied for possible applications in hydrogen generation and plasma assisted combustion. However, the kinetic aspects of plasma reforming have not been well understood yet, especially for the reforming of liquid fuels. In this study, a kinetic model was derived for the analysis of diesel partial oxidation assisted by plasma. Using a rotating arc as the plasma source, the effects of the oxygen-to-fuel ratio, specific energy input, temperature, and residence time on the reaction kinetics were investigated. A derived reaction model successfully describes the changes in the selectivity towards hydrogen relative to the amount of energy provided for the generation of plasma and the oxygen-to-fuel ratio in the reforming process.     

Antioxidative and antimicrobial effects of low molecular weight shrimp chitosan and its derivatives on seasoned-dried Pangasius fillets

This study was performed to evaluate the efficacy and applicability of low molecular weight shrimp chitosan (LMWC) and its derivatives (chitosan nanoparticles, CN; chitosan hydrochloride salt, CHS) as a preservative against lipid oxidation and microbial growth in seasoned-dried Pangasius hypophthalmus fillets during storage. All chitosans exhibited antioxidant activity in vitro (2,2-diphenyl-1-picrylhydrazyl radical scavenging activity, total reducing power ability and lipid peroxidation inhibition activity). The lipid oxidation in dried pangasius fillets that were seasoned by immersing in a solution containing 1.5% chitosan was suppressed during the 8-week storage; such effect was more effective than immersing in a solution containing 0.05% vitamin C. Likewise, LMWC and its derivatives were more effective in inhibiting microbial growth (lower total viable count and yeast/mould counts) than the control. These results clearly show that LMWC and its derivatives could be a potent antioxidant and antimicrobial preservative in seasoned-dried pangasius fillets during 8-week storage at 20 °C.     

Simultaneous production of gaseous fuels with degradation of Rhodamine B using a 40 kHz double-bath-type sonoreactor

This work proposed a novel double-bath-type sonoreactor to demonstrate the possibility of applying ultrasound power for simultaneous production of gaseous fuels with degradation of Rhodamine B (RhB). The developed double-bath-type sonoreactor allows concentrating the energy of the ultrasonic waves to a limited region and, consequently allows the acoustic intensity in there to be increased approximately 30-fold compared to that can be created in a normal ultrasonic bath at the same applied power. The effect of acoustic intensity, temperature of water bath, static and bubbling argon atmosphere, initial RhB concentration, and dissolved gases on the sonochemical activity both in terms of RhB degradation and gaseous fuel productions were fully investigated. The possible pathways for the simultaneous production of gaseous fuels with degradation of RhB were elucidated. Sonochemical degradation of RhB was successfully analysed by Langmuir-Hinshelwood-type kinetics.