Physico-mechanical properties of particleboard made from heat-treated rubberwood particles

Physico-mechanical properties of particleboard fabricated from heat-treated rubberwood particles were investigated. Reduction in water absorption and mass loss were observed in heat-treated rubberwood particles, and it was associated with the properties of particleboard. The density and moisture content of the particleboard decreased with increasing treatment temperature and time. Heat treatment of particles improved the dimensional stability of the particleboard, but the mechanical properties were adversely affected.     

Terthiophene-cyanovinylene π-conjugated polymers as donor material for organic solar cells

Conjugated polymers of hybrid structure containing cyanovinylene linkages have been synthesized by Knoevenagel condensation of diformyl terthienyls with para-dicyanomethylbenzene. UV–vis and cyclic voltammetric data show that these polymers combine reduced band gap, improved light-harvesting properties and low lying HOMO level. Whereas the very low solubility of the polymers did not allow the fabrication of bulk heterojunction solar cells, bilayer heterojunction solar cells have been realized using thermally evaporated films of fullerene C₆₀ as acceptor material. The best devices show a maximum external quantum efficiency of ～20% and a power conversion efficiency of 0.40% under simulated AM 1.5 solar illumination.     

The effect of zirconia substitution on the high-temperature transformation of the monoclinic-prime phase in yttrium tantalate

Amorphous yttrium tantalate, as well as solid solutions containing zirconia, transform on heating to a monoclinic-prime phase and then, with further heating, to a crystalline tetragonal (T) solid solution phase at ～1450?°C. On subsequent cooling the tetragonal phase converts by a second-order displacive transformation to a different monoclinic phase not to the monoclinic-prime phase. On subsequent reheating and cooling, the phase transformation occurs between the monoclinic (M) and tetragonal phases, and the monoclinic-prime phase cannot be recovered. The limit of zirconia solubility in both the monoclinic-prime and monoclinic phases lies between 25 and 28?m/o ZrO₂, consistent with previous first-principles calculations. The monoclinic-prime phase is stable up to at least 1400?°C for 100?h for zirconia concentrations from 0 to ～60?m/o ZrO₂. This temperature exceeds the temperature of the equilibrium M-T phase transformation suggesting that the monoclinic-prime phase transforms directly to the tetragonal phase by a reconstructive transformation and is unaffected by the zirconia in solid solution.     

Relationship between Hazen–William and Colebrook–White Roughness Values

Despite advances in computing technology and derivation of explicit approximation formulas, the experimentally verified and widely applicable Colebrook–White friction factor formula is often rejected in favor of the limited and less accurate Hazen–Williams equation. The general reluctance of practicing engineers to embrace the Colebrook–White formula may be due to the relatively large available database for Hazen–Williams C coefficient values versus a relatively small database of the equivalent sand roughness ks values required by the Colebrook–White equation. Until now, converting C to ks required knowledge of both the Reynolds number and pipe diameter originally used to determine C. The current effort derives implicit equations relating C to ks that do not require additional information and compare well with published data. The exact solution is approximated with a single explicit equation, accurate to within 4% error.     

Controlling Electrochemically Induced Volume Changes in Conjugated Polymers by Chemical Design: from Theory to Devices

Electrochemically induced volume changes in organic mixed ionic-electronic conductors (OMIECs) are particularly important for their use in dynamic microfiltration systems, biomedical machinery, and electronic devices. Although significant advances have been made to maximize the dimensional changes that can be accomplished by OMIECs, there is currently limited understanding of how changes in their molecular structures impact their underpinning fundamental processes and their performance in electronic devices. Herein, a series of ethylene glycol functionalized conjugated polymers is synthesized, and their electromechanical properties are evaluated through a combined approach of experimental measurements and molecular dynamics simulations. As demonstrated, alterations in the molecular structure of OMIECs impact numerous processes occurring during their electrochemical swelling, with sidechain length shortening decreasing the number of incorporated water molecules, reducing the generated void volumes and promoting the OMIECs to undergo different phase transitions. Ultimately, the impact of these combined molecular processes is assessed in organic electrochemical transistors, revealing that careful balancing of these phenomena is required to maximize device performance.     

Energy storage in ultrathin solid oxide fuel cells

The power output of hydrogen fuel cells quickly decreases to zero if the fuel supply is interrupted. We demonstrate thin film solid oxide fuel cells with nanostructured vanadium oxide anodes that generate power for significantly longer time than reference porous platinum anode thin film solid oxide fuel cells when the fuel supply is interrupted. The charge storage mechanism was investigated quantitatively with likely identified contributions from the oxidation of the vanadium oxide anode, its hydrogen storage properties, and different oxygen concentration at the electrodes. Fuel cells capable of storing charge even for short periods of time could contribute to ultraminiaturization of power sources for mobile energy.     

Development of a Method to Produce Freeze-Dried Cubes from 3 Pacific Salmon Species

Abstract: Freeze-dried boneless skinless cubes of pink (Oncorhynchus gorbuscha), sockeye (Oncorhynchus nerka), and chum (Oncorhynchus keta) salmon were prepared and physical properties evaluated. To minimize freeze-drying time, the kinetics of dehydration and processing yields were investigated. The physical characteristics of the final product including bulk density, shrinkage, hardness, color, and rehydration kinetics were determined. Results showed that freeze-dried salmon cubes from each of the 3 Pacific salmon species can be produced with a moisture content of less that 10% and a_w less 0.4 and freeze-drying time of 9 h. Processing yields ranged from 26% to 28.4%, depending on fish species. Shrinkage was less than 12% and rehydration of freeze-dried cubes was rapid. The value-added products developed have the potential to be utilized as ingredients for ready-to-eat soups, as snack food, salad topping, and baby finger-food. Practical Application: Freeze-drying removes water from food products without heating them; therefore, this type of drying process yields very high-quality dried foods. In this study, a freeze-dry process was established to produce small cubes of Alaska pink, sockeye, and chum salmon. The goals were to shorten typical freeze-drying time while producing acceptable product characteristics. The freeze-drying process developed took only 9 h to remove about 97% of the moisture of diced Pacific salmon fillets. The freeze-dried salmon cubes produced can be used as ingredients for dehydrated ready-to-eat soups, as baby finger-foods, or as salad toppings.