Hydrogen production characteristics of the organic fraction of municipal solid wastes by anaerobic mixed culture fermentation

The hydrogen production from the organic fraction of municipal solid waste (OFMSW) by anaerobic mixed culture fermentation was investigated using batch experiments at 37 degrees C. Seven varieties of typical individual components of OFMSW including rice, potato, lettuce, lean meat, oil, fat and banyan leaves were selected to estimate the hydrogen production potential. Experimental results showed that the boiling treated anaerobic sludge was effective mixed inoculum for fermentative hydrogen production from OFMSW. Mechanism of fermentative hydrogen production indicates that, among the OFMSW, carbohydrates is the most optimal substrate for fermentative hydrogen production compared with proteins, lipids and lignocelluloses. This conclusion was also substantiated by experimental results of this study. The hydrogen production potentials of rice, potato and lettuce were 134 mL/g-VS, 106 mL/g-VS, and 50 mL/g-VS respectively. The hydrogen percentages of the total gas produced from rice, potato and lettuce were 57-70%, 41-55% and 37-67%. 2008 International Association for Hydrogen Energy.

A NEW METHOD FOR DETECTING SUBTLE CHANGES IN SI-H BONDS OF A-SI-H

A new method developed for detecting possible subtle changes in Si-H bonds of a-Si:H after light soaking is described in detail. The method promises a sensitivity orders of magnitude higher than that reached by the usual IR spectrometer. Some preliminary results on phosphorus doped a-Si:H are given.

Copper(I)-Catalyzed Aryl Bromides To Form Intermolecular and Intramolecular Carbon-Oxygen Bonds

A highly efficient Cu-catalyzed C-O bond-forming reaction of alcohol and aryl bromides has been developed. This transformation was realized through the use of copper(I) iodide as a catalyst, 8-hydroxyquinoline as a ligand, and K3PO4 as a base. A variety of functionalized substrates were found to react under these reaction conditions to provide products in good to excellent yields.

Characterization and properties of biodegradable poly(hydroxyalkanoates) and 4,4-dihydroxydiphenylpropane blends: Intermolecular hydrogen bonds, miscibility and crystallization

Intermolecular hydrogen bonds, miscibility, crystallization and thermal stability of the blends of biodegradable poly(3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [P(3HB-3HHx)] with 4,4-dihydroxydiphenylpropane (DOH2) were investigated by FTIR, C-13 Solid state NMR, DSC, WAXD and TGA. Intermolecular hydrogen bonds were found in both blend systems, which resulted from the carbonyl groups in the amorphous phase of both polyesters and the hydroxyl groups of DOH2. The intermolecular interaction between P(3HB-3HHx) and DOH2 is weaker than that between PHB and DOH2 owing to the steric hindrance of longer 3HHx side chains. Because of the effect of the hydrogen bonds, the chain mobility of both PHB and P(3HB-3HHx) components was limited after blending with DOH2 molecules. Single glass transition temperature depending on the composition was observed in all blends, indicating that those blends were miscible in the melt. The addition of DOH2 suppressed the crystallization of PHB and P(3HB-3HHx) components. Moreover, the crystallinity of PHB and P(3HB-3HHx) components also decreased with increasing DOH2 content in the blends.

Mossbauer spectroscopy and chemical bonds in BaFe12O19 hexaferrite

Barium hexaferrite was synthesized by chemical co-precipitation. Its Mossbauer spectra were obtained. A semi-empirical model, based on the Phillips theory of bonding, has been developed for quantitative explanation of the Mossbauer isomer shifts of Fe ions in BaFe12O19 crystals. The results show that, using the relationship between isomer shifts and covalency, the site assignments in hexaferrites will be resolved easily. This paper provides a powerful tool for studying other members of the hexagonal ferrimagnetic oxides family.

Effect of hydrogen bonds on optical nonlinearities of inorganic crystals

This work probes the role of hydrogen bonds (such as O-H ... O and N-H ... O) in some inorganic nonlinear optical (NLO) crystals, such as HIO3, NH4H2PO4 (ADP), K[B5O6(OH)(4)] . 2H(2)O (KB5) and K2La(NO3)(5) . 2H(2)O (KLN), from the chemical bond standpoint. Second order NLO behaviors of these four typical inorganic crystals have been quantitatively studied, results show hydrogen bonds play a very important role in NLO contributions to the total nonlinearity. Conclusions derived here concerning the effect of hydrogen bonds on optical nonlinearities of inorganic crystals have important implications with regard to the utilization of hydrogen bonds in the structural design of inorganic NLO crystals. (C) 1999 Elsevier Science B.V. All rights reserved.

The role of Li-O bonds in calculations of nonlinear optical coefficients of LiXO3-type complex crystals

The second-order nonlinear optical (NLO) tenser coefficients of LiXO3 (X = I; Nb or Ta) type complex crystals have been calculated using the chemical bond theory of complex crystals. Contributions of each type of bond to the total second-order NLO coefficient d(ij) and the linear susceptibility X are quantitatively determined. All tensor values thus calculated are in good agreement with experimental data. The Li-O bonds are found to be an important group in the contributions to the total NLO tenser coefficient, especially for those in LiNbO3 and LiTaO3. The importance of Li-O bonds depends on the environment of Li atom in these crystals.