Search

An energy production system that combines biomass and fuel cells produces much energy with minimal environmental impact. However, the hydrogen sulfide (H2S) contained in gasified biomass degrades fuel cell performance, thus negating the advantages of this combination. In this study, the removal of H2S by adsorption after biomass gasification was investigated. Metal oxides with high adsorption performance are common H2S adsorbents. However, they have a significant environmental impact in terms of metal depletion, which is an environmental impact indicator. Therefore, neutralized sediment materials from mine drainage treatments can be used as H2S adsorbents. A previous study found that the adsorption performance of H2S adsorbents is equivalent to that of metal oxides, especially in the high-temperature zone (300 °C), and the environmental impact is considerably lower than that of metal oxides. However, because the neutralized sediment is a powder (Φ 4.5 μm on average), there is a possibility that the gas will not flow due to the pressure drop when it is used in a large adsorption column. Therefore, in this study, we propose the use of granulated neutralized sediments for practical plant operations. No studies have investigated the adsorption performance of granulated neutralized sediment through experiments or quantitatively investigated the effect of using waste material as a H2S adsorbent to reduce the environmental impact of hydrogen production. Based on these data, the sulfur capture capacity of the granulated neutralized sediment was experimentally investigated. The extent to which the environmental impact of the hydrogen production system could be reduced when granulated neutralized sediment was used as the H2S adsorbent was assessed. Note that the granulated neutralized sediment is formed with about a Φ 0.56–1.25 mm diameter. The granulated neutralized sediment exhibited approximately 76.8% of the adsorption performance of zinc oxide (ZnO) on a conventional adsorbent. In terms of the LCA, the global warming potential (GWP) and the abiotic depletion potential (ADP) were improved by approximately 0.89% (GWP) and 55.3% (ADP) in the entire hydrogen production process. This study demonstrated that the use of waste materials can significantly reduce the environmental impact on the entire system. [ABSTRACT FROM AUTHOR]

The FePt particles synthesized by polyoi process using tetraethylene glycol (TEG) as reducing agent at reaction temperatures 200 [degrees]C and 300 [degrees]C are superparamagnetic and ferromagnetic, respectively. The crystal structure of these particles is analyzed using XRD, XAS, and ASAXS to understand the formation of these particles at different heating temperatures. The results suggest that at 200 [degrees]C particles with Pt rich FePt core and amorphous shell rich in Fe are formed. However, when the reaction solution is annealed at 300 [degrees]C, sintering of several small particles occur. On the other hand, when hexachloroplatinum as nucleation control agent and a carboxylic acid as complex agent was added into the reaction solution, homogeneous alloy FePt particles with relatively large grain size of about 8 nm were obtained. In the process of forming the alloy nanoparticles, precipitated small particles were sintered at the amorphous interface and crystallization progresses along with ordering resulting in the formation of partially ordered ferromagnetic FePt. Index Terms--ASAXS, fcc-FePt, fct-FePt, polyol process, XAFS.

Perpendicular Co-Cr media were deposited on polyimide substrates by sputtering using an electron-cyclotron-resonance microwave plasma in an Ar sputtering gas pressure ranging from 3x[10.sup.-2] to 8x[10.sup.-2] Pa at a target to substrate distance from 170 to 230 mm. The accelerating voltage of the ions which bombard the media surface during deposition drastically affects the crystallographic and magnetic properties of Co-Cr films. Co-Cr media (50 nm in thickness) with good preferred crystal orientation ([Delta][[Theta].sub.50] less than 5 degrees), high perpendicular magnetic anisotropy ([H.sub.k] higher than 4 kOe), high perpendicular coercivity ([H.sub.c[perpendicular]] over 1400 Oe) and no initial layer were successfully deposited when the ion accelerating voltage was reduced less than about 20 V.

The FePt particles synthesized by polyol process using tetraethylene glycol (TEG) as reducing agent at reaction temperatures 200 °C and 300 °C are superparamagnetic and ferromagnetic, respectively. The crystal structure of these particles is analyzed using XRD, XAS, and ASAXS to understand the formation of these particles at different heating temperatures. The results suggest that at 200 °C particles with Pt rich FePt core and amorphous shell rich in Fe are formed. However, when the reaction solution is annealed at 300 °C, sintering of several small particles occur. On the other hand, when hexachloroplatinum as nucleation control agent and a carboxylic acid as complex agent was added into the reaction solution, homogeneous alloy FePt particles with relatively large grain size of about 8 nm were obtained. In the process of forming the alloy nanoparticles, precipitated small particles were sintered at the amorphous interface and crystallization progresses along with ordering resulting in the formation of partially ordered ferromagnetic FePt. [ABSTRACT FROM AUTHOR]

Research to improve the dimensional properties of silver nanowires (Ag NWs) for transparent conductive film (TCF) applications are being carried out intensively. However, the protocol for the designed synthesis of high-quality Ag NWs is yet to be developed due to the inadequacy of knowledge on the role of parameters. Here, we attempt to elucidate the role played by the parameters and propose a monoalcohol-copolymer based system for the designed synthesis of Ag NWs superior in quality to the one synthesized using conventional ethylene glycol (EG)-polyvinylpyrrolidone (PVP) system. The key findings of the study are as follows: (1) the solubility of Ag source and the partially formed AgCl particles in monoalcohols was found to play an important role not only in the reduction to metallic Ag but also on the uniaxial growth, (2) the adsorption of capping agents on Ag NWs was carried through O and N atoms in the base molecule and their binding energies indicated that the strength is the key parameter to obtain Ag NWs with high aspect ratio, (3) the properties of nanowire could be enhanced through copolymerization of VP and base molecules that have O- and N-based ligands, and (4) the influence of copolymerization on the physical and chemical properties of the surface active agent has been theoretically and experimentally verified. Consequently, we succeeded in the development of a new technique to synthesize high yield of Ag NWs with improved aspect ratio than EG-PVP system by using benzyl alcohol as reducing solvent and N -vinylpyrrolidone/ N , N -diethylaminoethyl metacrylate copolymer as a capping agent. The optical transmittance and electrical resistivity of TCFs prepared using the Ag NWs with an average diameter of 43 nm, and an average length of 13 μm were 98.6% and R: 49.1 Ω/□, respectively. [ABSTRACT FROM AUTHOR]