Preliminary investigation of algal cellulose I. X-ray intensity data

1970 ◽  
Vol 222 (1) ◽  
pp. 109-118 ◽  
Author(s):  
I.A. Nieduszynski ◽  
E.D.T. Atkins
Keyword(s):  
Preliminary Investigation ◽  
Intensity Data ◽  
Cellulose I ◽  
X Ray ◽  
Algal Cellulose

Use of TALP with laboratory powder diffraction data from 2D detectors

2013 ◽  
Vol 28 (S2) ◽  
pp. S481-S490
Author(s):  
Oriol Vallcorba ◽  
Anna Crespi ◽  
Jordi Rius ◽  
Carles Miravitlles
Keyword(s):  
Organic Compounds ◽  
Structural Study ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Powder Pattern ◽  
Experimental Setup ◽  
Intensity Data ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Molecular Compounds

The viability of the direct-space strategy TALP (Vallcorba et al., 2012b) to solve crystal structures of molecular compounds from laboratory powder diffraction data is shown. The procedure exploits the accurate metric refined from a ‘Bragg-Brentano’ powder pattern to extract later the intensity data from a second ‘texture-free’ powder pattern with the DAJUST software (Vallcorba et al., 2012a). The experimental setup for collecting this second pattern consists of a circularly collimated X-ray beam and a 2D detector. The sample is placed between two thin Mylar® foils, which reduces or even eliminates preferred orientation. With the combination of the DAJUST and TALP software a preliminary but rigorous structural study of organic compounds can be carried out at the laboratory level. In addition, the time-consuming filling of capillaries with diameters thinner than 0.3mm is avoided.

scholarly journals Stable, metastable and unstable cellulose solutions

2017 ◽  
Vol 4 (8) ◽  
pp. 170487 ◽  
Author(s):  
Marta Gubitosi ◽  
Pegah Nosrati ◽  
Mona Koder Hamid ◽  
Stefan Kuczera ◽  
Manja A. Behrens ◽  
...  
Keyword(s):  
Microcrystalline Cellulose ◽  
Small Angle ◽  
Supersaturated Solution ◽  
Cellulose Ii ◽  
Cellulose I ◽  
Tetrabutylammonium Hydroxide ◽  
X Ray ◽  
Stable Regime ◽  
X Ray Scattering ◽  
A Minor

We have characterized the dissolution state of microcrystalline cellulose (MCC) in aqueous tetrabutylammonium hydroxide, TBAH(aq), at different concentrations of TBAH, by means of turbidity and small-angle X-ray scattering. The solubility of cellulose increases with increasing TBAH concentration, which is consistent with solubilization driven by neutralization. When comparing the two polymorphs, the solubility of cellulose I is higher than that of cellulose II. This has the consequence that the dissolution of MCC (cellulose I) may create a supersaturated solution with respect to cellulose II. As for the dissolution state of cellulose, we identify three different regimes. (i) In the stable regime, corresponding to concentrations below the solubility of cellulose II, cellulose is molecularly dissolved and the solutions are thermodynamically stable. (ii) In the metastable regime, corresponding to lower supersaturations with respect to cellulose II, a minor aggregation of cellulose occurs and the solutions are kinetically stable. (iii) In the unstable regime, corresponding to larger supersaturations, there is macroscopic precipitation of cellulose II from solution. Finally, we also discuss strong alkali solvents in general and compare TBAH(aq) with the classical NaOH(aq) solvent.

Determination of Absolute from Relative X-Ray Intensity Data

Nature ◽  
1942 ◽  
Vol 150 (3796) ◽  
pp. 151-152 ◽  
Author(s):  
S. H. YÜ
Keyword(s):  
Intensity Data ◽  
X Ray

Research on Crystallinity, Morphology of Cotton Subjected to Enzyme and Crosslinking Treatment

2017 ◽  
Vol 893 ◽  
pp. 71-76 ◽  
Author(s):  
Md. Nahid Pervez ◽  
Faizan Shafiq ◽  
Muhammad Munib Jilani ◽  
Zahid Sarwar ◽  
Ying Jie Cai
Keyword(s):  
Crystalline Structure ◽  
Cotton Fiber ◽  
Crystallinity Index ◽  
Cotton Fibers ◽  
Cellulose I ◽  
X Ray ◽  
Cotton Fibres ◽  
Ft Ir ◽  
Crystalline Nature ◽  
Crosslinking Agents

This paper explores the effect of prior enzymatic treatment on non-formaldehyde crosslinked cotton fiber and crystalline structure of cotton fibers after enzyme, crosslinking and a combination of enzyme and crosslinking treatments were examined by X-ray diffractometer. Results showed that during crosslinking treatment crystallinity index (%) values were increased with reduced crystallinity size and crosslinked of enzyme treated cotton did not change the crystalline nature of cotton (i.e. it was Cellulose I). In addition, by analysing FT-IR and SEM data it is confirmed that uniform presence of crosslinking agents was visible on cotton fibres.

X-Ray Orientation of Equatorial Planes in Swollen and Stretched Cellulosic Fibers

1988 ◽  
Vol 58 (5) ◽  
pp. 299-301 ◽  
Author(s):  
S. Sreenivasan ◽  
K. R. Krishna Iyer ◽  
P. K. Chidambareswaran ◽  
N. B. Patil
Keyword(s):  
Cotton Fibers ◽  
Cellulose I ◽  
X Ray ◽  
Cellulosic Fibers ◽  
Viscose Fibers

X-ray orientation profiles were recorded that pertained to the three equatorial planes from cotton fibers containing both cellulose I and II lattices and from viscose fibers. The changes in orientation brought about by swelling and stretching treatments could be accurately followed by studying the distribution of any one of the diffraction arcs.

Eco-Friendly Preparation of Nanofibrillated Cellulose from Water Hyacinth Using NaOH/Urea Pretreatment

2020 ◽  
Vol 990 ◽  
pp. 225-230
Author(s):  
Kraiwit Pakutsah ◽  
Duangdao Aht-Ong
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Water Hyacinth ◽  
Aqueous Suspension ◽  
Nanofibrillated Cellulose ◽  
Cellulose Ii ◽  
Cellulose I ◽  
X Ray ◽  
Transmission Electron ◽  
Water Hyacinth Fiber

In this work, we described an effective approach to prepare nanofibrillated cellulose (NFC) with cellulose II structure under mild condition. Firstly, the water hyacinth (WH) was subjected to a series of a two-step chemical treatment, NaOH/urea pretreatment, and mechanical defibrillation at different defibrillation times. After that, raw water hyacinth fiber (RWF), bleached water hyacinth fiber (BWF), NaOH/urea pretreated water hyacinth fiber (PWF), and the resulting NFC were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD) as well as rheological measurements. It was found that RWF and BWF exhibited cellulose I crystal structure, whereas PWF and the obtained NFC possessed cellulose II crystal structure. FTIR analysis confirmed the evidence that no other chemical reactions preferentially occurred during both NaOH/urea pretreatment and mechanical defibrillation. As evidenced by rheological properties analysis, the NFC aqueous suspension with a gel-like structure demonstrated a shear-thinning behavior. The obtained NFC could potentially be utilized as a reinforcement for polymeric composites.

scholarly journals Preliminary investigation of chlorine speciation in zirconolite glass-ceramics for plutonium residues by analysis of Cl K-edge XANES

MRS Advances ◽  
2019 ◽  
Vol 5 (1-2) ◽  
pp. 37-43
Author(s):  
Amber R. Mason ◽  
Stephanie M. Thornber ◽  
Martin C. Stennett ◽  
Laura J. Gardner ◽  
Dirk Lützenkirchen-Hecht ◽  
...  
Keyword(s):  
Chemical Shift ◽  
Absorption Edge ◽  
Glass Ceramic ◽  
Glass Phase ◽  
Preliminary Investigation ◽  
Glass Ceramics ◽  
Local Environment ◽  
Aluminosilicate Glass ◽  
X Ray ◽  
X Ray Absorption

ABSTRACTA zirconolite glass-ceramic material is a candidate wasteform for immobilisation of chlorine contaminated plutonium residues, in which plutonium and chlorine are partitioned to the zirconolite and aluminosilicate glass phase, respectively. A preliminary investigation of chlorine speciation was undertaken by analysis of Cl K-edge X-ray Absorption Near Edge Spectroscopy (XANES), to understand the incorporation mechanism. Cl was found to be speciated as the Cl- anion within the glass phase, according to the characteristic chemical shift of the X-ray absorption edge. By comparison with Cl K-edge XANES data acquired from reference compounds, the local environment of the Cl- anion is most closely approximated by the mineral marialite, in which Cl is co-ordinate to 4 x Na and/or Ca atoms.

Hyperspectral Cathodoluminescence Imaging and Analysis Extending from Ultraviolet to Near Infrared

2012 ◽  
Vol 18 (6) ◽  
pp. 1239-1245 ◽  
Author(s):  
C.M. MacRae ◽  
N.C. Wilson ◽  
A. Torpy ◽  
C.J. Davidson
Keyword(s):  
Rare Earth ◽  
Near Infrared ◽  
Preliminary Investigation ◽  
X Rays ◽  
Spectral Mapping ◽  
X Ray ◽  
Quantitative Electron Probe Microanalysis ◽  
Uv Visible ◽  
Intense Emission ◽  
Cathodoluminescence Imaging

AbstractThe measurement of near-infrared (NIR) cathodoluminescence (CL) with sufficient sensitivity to allow full spectral mapping has been investigated through the application of optimized grating spectrometers that allow the ultraviolet (UV), visible, and NIR CL spectra to be measured simultaneously. Two optical spectrometers have been integrated into an electron microprobe, allowing simultaneous collection of hyperspectral CL (UV-NIR), characteristic X-rays, and electron signals. Combined hyperspectral CL spectra collected from two natural apatite (Ca5[PO4]3[OH,F]) samples from Wilberforce (Ontario, Canada) and Durango (Mexico) were qualitatively analyzed to identify the emission centers and then deconvoluted pixel-by-pixel using least-squares fitting to produce a series of ion-resolved CL intensity maps. Preliminary investigation of apatite has shown strong NIR emissions associated primarily with the rare-earth element Nd. Details of growth and alteration were revealed in the NIR that were not discernable with electron-induced X-ray mapping. Intense emission centers from Nd3+ and Sm3+ were observed in the spectra from both apatites, along with minor emissions from other 3+ rare-earth elements. Quantitative electron probe microanalysis was performed on points within the mapped area of the Durango apatite to produce a calibration line relating cathodoluminescent intensity of the fitted peak centered at 1,073 nm (1.156 eV) to the Nd concentration.

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