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A 3-D reference model for wideband multiple-input multiple-output (MIMO) mobile-to-mobile (M-to-M) channels is reviewed along with its corresponding first- and second-order channel statistics. To validate the reference model, an experimental MIMO M-to-M channel-sounding campaign was conducted for M-to-M vehicular communication with vehicles that travel along surface streets and expressways in a metropolitan area. To compare the first- and second-order channel statistics that were obtained from the reference model with those obtained from the empirical measurements, a new maximum-likelihood-based stochastic estimator is derived to extract the relevant model parameters from the measured data. The measured data is processed and compared with the analytical results. The close agreement between the analytically and empirically obtained channel statistics confirms the utility of the proposed reference model and the method for estimating the model parameters. Index Terms--Channel sounding, mobile-to-mobile (M-to-M) channels, parameter estimation, wideband channel model.

The successful detection of natural azaspiracids by antibodies raised against a synthetic hapten representing the common C28-C40 domain of the azaspiracids is reported. The advantages of applying synthetic organic chemistry to produce carefully designed haptens containing conserved substructures of complex toxin molecules are described.

Over twenty million tons of pineapples have been produced annually worldwide, but their waste is mostly discarded or burnt after harvesting. In this work, the high-value added aerogels from the pineapple leaf waste are developed for the first time by using polyvinyl alcohol (PVA) cross-linkers and a cost-effective freeze drying process. The pineapple fibre (PF) aerogels have highly porous structures with the porosities of 96.98–98.85%, ultra-low densities of 0.013–0.033 g/cm3, and hydrophobicity with water contact angles of approximately 140°, after a surface modification with methyltrimethoxysilane (MTMS). The effects of PF concentrations (0.5–2.0 wt.%) on oil and organic solvent adsorption are investigated comprehensively. Experimental results indicate that the hydrophobic PF aerogels can adsorb motor oil up to 37.9 g/g, approximately two times greater than commercial polypropylene and polyurethane sorbents. The pseudo-second order model can provide a good fit for the oild adsorption kinetics of the developed aerogels. [ABSTRACT FROM AUTHOR]

Pineapple has been known as one of the most popular tropical fruits in Vietnam with a production of over 674,000 t in 2018. However, by-products from pineapple cultivation account for approximately 65 % of the fresh fruit weight and are mostly being dumped, decomposed or burnt now. Therefore, it has recently raised great concern about environmental pollution. For the first time, extracted fibres from pineapple leaves being utilized for developing successfully eco-friendly and cost-effective pineapple fibres (PFs) aerogels by using polyvinyl alcohol as a cross-linker and following a freeze-drying method. The morphology of the PFs aerogels can be controlled well by changing the PFs concentration (0.5 - 2.0 wt%). The PFs aerogels exhibit extremely low densities (12.7 - 32.6 kg/m3) and high porosities (96.9 - 98.8 %). The BET result shows that the surface area of the PFs aerogel has up to 5.6 m2/g and their pore size of 1.3 - 2.2 nm. The developed PFs aerogels show extremely low thermal conductivities ranging from 0.030 to 0.034 W/m.K. Due to the low Young's modulus values ranging from 0.47 - 7.86 kPa, the PFs aerogels are flexible and can be used for heat insulation of the buildings as well as food preservation. [ABSTRACT FROM AUTHOR]

Silica aerogels have attracted great attention owing to their outstanding properties such as ultralow density, high porosity, high surface area, and low thermal conductivities. Their poor mechanical properties and hydrophilicity constrain their practical applications. In this work, phenyltrimethoxysilane (PTMS) and polyvinyl alcohol (PVA) were added into methyltrimethoxysilane (MTMS)-based silica aerogels to enhance their mechanical properties. It was found that PTMS considerably improved the hydrophobicity of MTMS silica aerogels with an increase in water contact angles from 115° to 150°. The addition of PVA considerably increased the hardness, morphology, density, porosity, surface area, and thermal conductivity of MTMS silica aerogels. When PVA concentration was increased from 0 to 2 %, the aerogel hardness, density, and thermal conductivity were also increased from 0 to 14 %, 0.072 to 0.11 g/cm³, and 0.035 to 0.046 W/m.K. In contrast, the aerogel became less porous and the porosity reduced from 97.2 % to 95.72 % and BET surface area decreased from 389 to 43 m²/g. [ABSTRACT FROM AUTHOR]

Bimetallic electrocatalysts based on Pd such as PdAg, PdNi and PdSn, have shown high efficiencies for ethanol oxidation reaction (EOR). In this study, a novel PdAg core-shell nanowire structure (PdAg-MW) with a Pd:Ag molar ratio of 1:10 was synthesized via a simple two-step process under microwave (MW) pulse mode irradiation in polyol solvent. The effect of MW irradiation time on the formation of Pd shell on Ag nanowires was investigated and compared to the sample PdAg-CP prepared by conventional polyol process. The catalytic ability and stability of the catalysts for ethanol electro-oxidation in KOH solution were examined by using cyclic voltammetry (CV), linear sweep voltammetry (LSV) and chronoamperometry (CA) measurements. Tolerance to CO gas was also studied by CO stripping analysis. Surface morphology, structure and composition of the materials were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and energy-dispersive X-ray (EDX). The results showed that PdAg-MWs possessed a unique morphology and hollow structure can be achieved at 6-8 times of MW heating. The EOR peak current value is achieved about 3156 mA/mg Pd for PdAg-MW/C, which is superior to Pd nanoparticles/C (PdNPs/C) and PdAg-CP/C, making it a promising Pd-based anodic electrocatalyst for alkaline direct ethanol fuel cells. [ABSTRACT FROM AUTHOR]

Despite the great potential of zinc oxide (ZnO) nanostructures as a sensing material for high-performance gas sensors, the correlation between the morphology of ZnO nanostructure and its gas-sensing performance has not been systematically investigated yet. In this work, ZnO nanostructures with controlled morphologies were synthesized by low-temperature solution route and chemical bath deposition method. Thin film gas sensors were fabricated from the nanostructures and the sensor performance such as the response, recovery time, and stability was examined for several gases. It is demonstrated that the gas-sensing performance of a ZnO nanostructure sensor is strongly influenced by its morphology. One dimensional ZnO nanocones are highly promising for practical application to gas sensors, due to their large surface area per unit mass and unique conical structure. [ABSTRACT FROM AUTHOR]

A two-step processing was developed to prepare Yb2Si2O7-SiC nanocomposites. Yb2Si2O7-Yb2SiO5-SiC composites were first fabricated by a solid-state reaction/hot-pressing method. The composites were then annealed at 1250°C in air for 2 hours to activate the oxidation of SiC, which effectively transformed the Yb2SiO5 into Yb2Si2O7. The surface cracks purposely induced can be fully healed during the oxidation treatment. The treated composites have improved flexural strength compared to their pristine composites. The mechanism for crack healing and silicate transformation have been proposed and discussed in detail. [ABSTRACT FROM AUTHOR]