The Properties of Sintered Calcium Phosphate with [Ca]/[P] = 1.50

In order to obtain the properties of the sintered as-dried calcium phosphate with [Ca]/[P] = 1.50, the characteristics of sintered pellets have been investigated using X-ray diffraction (XRD), inductively coupled plasma-mass spectrometry (ICP-MS), Fourier-transform infrared (FT-IR) spectra, Vickers hardness indentation and scanning electron microscopy (SEM). When the pellet samples were sintered between 700 °C and 1200 °C for 4 h, the hydroxyapatite (Ca₁₀(PO₄)₆(OH)₂, HA) still maintained the major phase, accompanied with the rhenanite (NaCaPO₄) as the secondary phase and β-tricalcium phosphate (β-Ca₃(PO₄)₂, β-TCP) as the minor phases. In addition, the HA partially transformed to α-tricalcium phosphate (α-Ca₃(PO₄)₂, α-TCP) and tetracalcium phosphate (Ca₄(PO4)₂O, TTCP), when the pellet samples were sintered at 1300 °C and 1400 °C, respectively, for 4 h. The maximum density and Vickers Hardness (HV) of sintered pellet samples were 2.85 g/cm³ (90.18% theoretical density (T.D.)) and 407, which appeared at 1200 °C and 900 °C, respectively.     

Anaerobic co‐digestion of food waste leachate and piggery wastewater for methane production: statistical optimization of key process parameters

BACKGROUND: Anaerobic co‐digestion of refractory liquid organic wastes is an alternative environmental management strategy with economic benefits arising out of biogas production. Laboratory‐scale experimental investigations were carried out on the anaerobic co‐digestion of two liquid organic wastes, food waste leachate (FWL) and piggery wastewater (PWW). Three important parameters affecting methane yield were chosen for this study, namely, mixing ratio, alkalinity and salinity, which were optimized using response surface methodology. RESULTS: The results were analyzed statistically and the optimum conditions identified as: mixing ratio (FWL: PWW) 33 (in terms of volatile solid, w/w) (2 on v/v), alkalinity 2850 mg CaCO₃ L^?1, and salinity 3.4 g NaCl L^?1. Under the optimum conditions, a cumulative methane yield (CMY) of 310 mL CH₄ g^?1 VS_added and VS reduction (VSR) of 54% were predicted. Mixing ratio and alkalinity showed the greatest individual and interactive effects on CMY and VSR (P < 0.05). A confirmation experiment under optimum conditions showed a CMY and VSR of 323 mL CH₄ g^?1 VS_added and 50%, respectively. This was only 1.04% and 1.1%, respectively, different from the predicted values. CONCLUSION: Anaerobic co‐digestion of FWL and PWW carried out under the optimum condition may be a feasible and efficient treatment option for methane production. Copyright © 2012 Society of Chemical Industry     

A cross‐cultural comparison of colour emotion for two‐colour combinations

Psychophysical experiments were conducted in the UK, Taiwan, France, Germany, Spain, Sweden, Argentina, and Iran to assess colour emotion for two‐colour combinations using semantic scales warm/cool, heavy/light, active/passive, and like/dislike. A total of 223 observers participated, each presented with 190 colour pairs as the stimuli, shown individually on a cathode ray tube display. The results show consistent responses across cultures only for warm/cool, heavy/light, and active/passive. The like/dislike scale, however, showed some differences between the observer groups, in particular between the Argentinian responses and those obtained from the other observers. Factor analysis reveals that the Argentinian observers preferred passive colour pairs to active ones more than the other observers. In addition to the cultural difference in like/dislike, the experimental results show some effects of gender, professional background (design vs. nondesign), and age. Female observers were found to prefer colour pairs with high‐lightness or low‐chroma values more than their male counterparts. Observers with a design background liked low‐chroma colour pairs or those containing colours of similar hue more than nondesign observers. Older observers liked colour pairs with high‐lightness or high‐chroma values more than young observers did. Based on the findings, a two‐level theory of colour emotion is proposed, in which warm/cool, heavy/light, and active/passive are identified as the reactive‐level responses and like/dislike the reflective‐level response. © 2010 Wiley Periodicals, Inc. Col Res Appl, 2012     

生物质对低浓度染料废物的协同多层吸收(英文)

Due to the high cost of adsorbents and their thermal regeneration in recent years,much research has focused on the search for cheaper adsorbents for treating wastewater from textile industry.The single component adsorption of an acidic dye,Acid Yellow 117,and a basic dye,Methylene Blue,onto several adsorbents—bamboo,waste wood,bamboo char,waste wood char,bamboo activated carbon,wood activated carbon and active carbon F400 were conducted.Based on a Langmuir analysis,the monolayer adsorption capacities were determined.Three of the adsorbents were selected for binary layer adsorption to check the multilayer concept and the potential application for better adsorbent usage.The two cheapest adsorbents,bamboo and wood are compared with the commercial activated carbon F400,and all three systems were successful.     

Synthesis of highly concentrated suspension of chemically converted graphene in organic solvents: Effect of temperature on the extent of reduction and dispersibility

We report the effect of temperature on the extent of graphene oxide reduction by hydrazine and the dispersibility of the resulting chemically converted graphene (CCG) in polar organic solvents. The extent of graphene oxide reduction at high temperatures was only slightly higher than at low temperatures (30–50 °C), while the dispersibility of the resulting CCG in organic solvents decreased markedly with increasing temperature. The low dispersibility of CCGs prepared at high temperatures was greatly affected by reduction and influenced by the formation of an irreversible agglomerate of CCG at high temperatures. The reduction of graphene oxide at low temperatures is necessary to prepare highly dispersible CCG in organic solvents. CCG prepared at 30 °C is dispersible in N-methyl-2-pyrrolidone concentrations as high as 0.71 mg/mL. The free-standing paper made of this CCG possessed an electrical conductivity of more than 22,000 S/m, one of the highest values ever reported.     

Large-scale and uniform preparation of pure-phase wurtzite GaAs NWs on non-crystalline substrates

One of the challenges to prepare high-performance and uniform III-V semiconductor nanowires (NWs) is to control the crystal structure in large-scale. A mixed crystal phase is usually observed due to the small surface energy difference between the cubic zincblende (ZB) and hexagonal wurtzite (WZ) structures, especially on non-crystalline substrates. Here, utilizing Au film as thin as 0.1 nm as the catalyst, we successfully demonstrate the large-scale synthesis of pure-phase WZ GaAs NWs on amorphous SiO₂/Si substrates. The obtained NWs are smooth, uniform with a high aspect ratio, and have a narrow diameter distribution of 9.5 ± 1.4 nm. The WZ structure is verified by crystallographic investigations, and the corresponding electronic bandgap is also determined to be approximately 1.62 eV by the reflectance measurement. The formation mechanism of WZ NWs is mainly attributed to the ultra-small NW diameter and the very narrow diameter distribution associated, where the WZ phase is more thermodynamically stable compared to the ZB structure. After configured as NW field-effect-transistors, a high I_ON/I_OFF ratio of 10⁴ − 10⁵ is obtained, operating in the enhancement device mode. The preparation technology and good uniform performance here have illustrated a great promise for the large-scale synthesis of pure phase NWs for electronic and optical applications.     

Advanced Surface of Fibrous Activated Carbon Immobilized with FeO/TiO2 for Photocatalytic Evolution of Hydrogen under Visible Light

FeO-doped TiO₂ nanoparticle photocatalysts were immobilized onto the surface of fibrous activated carbon (ACF) via a sol-gel process. As an adsorbent and photocatalyst, FeO-TiO₂ on immobilized ACFs (FeO-TiO₂/ACF) greatly improved the photocatalysis rate of hydrogen production as compared with pure TiO₂ and ACF-TiO₂ under UV irradiation and visible light. The addition of ACFs surface significantly reduced the photogenerated pairs of electrons-hole recombination, thereby promoting the photocatalysis action of doped photo-metal oxides of FeO-TiO₂. Co-doping of FeO onto the lattice of the TiO₂ approach can improve the absorption activity of visible light through photo-metal oxide of TiO₂ and further enhance hydrogen production under visible light. The photocatalytic fabrics (FeO-TiO₂/ACF) were effortlessly split out from the experimental solution for re-utilization and exhibited high stability even after five complete regeneration cycles.     

Photocatalytic degradation and heat reflectance recovery of waterborne acrylic polymer/ZnO nanocomposite coating

This work aims to clarify the photocatalytic degradation mechanism and heat reflectance recovery performance of waterborne acrylic polymer/ZnO nanocomposite coating. To fabricate the nanocomposite coating, ZnO nanoparticles (nano-ZnO) were dispersed into acrylic polymer matrix at the various concentrations from 1 to 6% (by total weight of resin solids). The photocatalytic degradation of nanocomposite coating under ultraviolet (UV) light irradiation has been investigated by monitoring its weight loss and chemical/microstructural/morphological changes. As the topcoat layer, its heat reflectance recovery has been evaluated under UV/condensation exposure by using an artificial dirty mixture of 85 wt% nanoclay, 10 wt% silica particles (1–5 μm), 1 wt% carbon black, and 2 wt% engine oil. After 108-cycle UV/condensation exposure, infrared spectra and weight loss analysis indicated that the maximal degradation for nanocomposite coating is observed at 1 wt% nano-ZnO. On the other hand, after 96 hr of UV light exposure, the nanocomposite coating with1 wt% nano-ZnO could restore effectively the reflective index of solar-heat reflectance coating (from 58.45 to 80.78%). Finally, the photodegradation mechanism of this waterborne acrylic polymer coating has been proposed as the UV-induced formation of CC CO conjugated double bonds. As a result, its self-cleaning phenomenon can be achieved as the recovery of heat reflectance.     

Fabrication and Thermal Dissipation Properties of Carbon Nanofibers Derived from Electrospun Poly(Amic Acid) Carboxylate Salt Nanofibers

Polyimides (PIs) possess excellent mechanical properties, thermal stability, and chemical resistance and can be converted to carbon materials by thermal carbonization. The preparation of carbon nanomaterials by carbonizing PI‐based nanomaterials, however, has been less studied. In this work, the fabrication of PI nanofibers is investigated using electrospinning and their transformation to carbon nanofibers. Poly(amic acid) carboxylate salts (PAASs) solutions are first electrospun to form PAAS nanofibers. After the imidization and carbonization processes, PI and carbon nanofibers can then be obtained, respectively. The Raman spectra reveal that the carbon nanofibers are partially graphitized by the carbonization process. The diameters of the PI nanofibers are observed to be smaller than those of the PAAS nanofibers because of the formation of the more densely packed structures after the imidization processes; the diameters of the carbon nanofibers remain similar to those of the PI nanofibers after the carbonization process. The thermal dissipation behaviors of the PI and carbon nanofibers are also examined. The infrared images indicate that the transfer rates of thermal energy for the carbon nanofibers are higher than those for the PI nanofibers, due to the better thermal conductivity of carbon caused by the covalent sp² bonding between carbon atoms.     

Studies on cross-linked polyurethane acrylate-based electrolyte consisting of reactive vinyl/divinyl diluents

A series of cross-linked polyurethane acrylate (PUA) electrolytes have been prepared by using 4,4′-methylene bis(phenyl isocyanate), polyethylene glycol, hydroxyethyl methacrylate and different reactive vinyl/divinyl diluents, such as methyl methacrylate (MMA), ethyl acrylate and acrylonitrile, tripropylene glycol diacrylate (TPGDA). The electrolytes were prepared by UV radiation induced cross-linking of the PUA-diluent mixture followed by swelling in a liquid electrolyte (LP-30). Depending upon the composition of the components, these electrolytes exhibited a wide range of mechanical and electrical properties. The system containing MMA as reactive diluent showed highest conductivity, but poor mechanical properties and stability in the liquid electrolyte. The TPGDA cross-linked system possesses a good combination of ionic conductivity and stability in liquid electrolytes. These systems showed good compatibility with Li-electrodes and sufficient electrochemical stability to allow safe operation in rechargeable Li-batteries.