Authors: M.Varman, H. Miyafuji, S. Saka
Comments: 21 Pages. M.Varman, H. Miyafuji, and S. Saka. "Fractionation and characterization of oil palm (Elaeis guineensis) as treated by supercritical water" Journal of Wood Science 56(6) (2010): 484-494.
In order to investigate a potential for the efficient utilization of oil palm (Elaeis guineensis), supercritical water treatment (380ºC/100MPa/8s) has been applied to fractionate into water-soluble portion and water-insoluble portion composing of methanol-soluble portion and methanol-insoluble residue for various parts of oil palm such as trunk, frond, mesocarp fibers, shell, empty fruit bunch (EFB) and kernel cake. These fractionated products were then characterized analytically, in which the water-soluble and methanol-soluble portions were determined to be mainly composed of carbohydrate-derived products and lignin-derived products, respectively. Besides, the methanol-insoluble residue was mainly composed of lignin more than 84wt%, and the phenolic hydroxyl contents determined by aminolysis method was higher than the untreated oil palm sample. In addition, an alkaline nitrobenzene oxidation analysis indicated that, the methanol-insoluble residue was less in oxidation products. These lines of findings implicate that the water-soluble portion could be utilized for organic acid production, whereas the methanol-soluble portion and its insoluble residue for phenolic chemical production.
Authors: Sosale Chandrasekhar
Comments: 10 Pages.
It is argued that the fundamental theory of X-ray diffraction is based on a flawed model of wave interference. This is because the macroscopic distances between the crystalline sample on the one hand, and the X-ray source and the detector on the other, cannot be defined to the accuracy of a fractional wave-length. Thus, the inherent ‘graininess’ of the detector surface does not support the idea of constructive or destructive interference of electromagnetic radiation. This critique then applies equally to the presumed extensions of ‘Bragg’s Law’, particularly the so-called phase problem. The phase problem is thus a theoretical construct that is, practically, an artefact of the Bragg derivation. The Bragg approach, however, has been ingeniously adapted to make contact with the structural theory of chemistry by various guises and protocols. These are, inter alia, based on ideas about crystal morphology and internal structure that preceded the Bragg approach. An alternative theory of X-ray scattering, however, needs also to be compatible with the structural theory to be practically meaningful. A model of scattering is proposed herein, that is based on absorption and emission by groups of atoms that are defined by a conventional lattice plane. The Bragg equation is thus re-interpreted as relating the energy of the emitted radiation and the angle of ‘reflection’. It is argued that the Bragg approach is essentially empirical, and that its apparent consistency with the structural theory is based on a synergistic evolution of theoretical ideas and experimental observation. In this, therefore, it is not unlike other spectroscopic techniques in common use for structure determination.