The Stability of Hydrated Aluminium Phosphate, ALPO4·1.5H2O

2006 ◽  
Vol 27 (11) ◽  
pp. 1217-1224 ◽  
Author(s):  
F. Lagno ◽  
G. P. Demopoulos
Keyword(s):  
Aluminium Phosphate ◽  
The Stability ◽  
Hydrated Aluminium

Kingite, a new hydrated aluminium phosphate mineral from Robertstown, South Australia

1957 ◽  
Vol 31 (236) ◽  
pp. 351-357 ◽  
Author(s):  
K. Norrish ◽  
Lillian E. R. Rogers ◽  
R. E. Shapter
Keyword(s):  
Refractive Index ◽  
Chemical Composition ◽  
Specific Gravity ◽  
Diffraction Pattern ◽  
South Australia ◽  
X Ray Diffraction ◽  
Aluminium Phosphate ◽  
X Ray ◽  
Phosphate Mineral ◽  
Hydrated Aluminium

SummaryA new hydrated aluminium phosphate mineral, kingite, from phosphate workings near Robertstown, South Australia, has an idealized formula Al2O3.Al(OH)3.P2O5.9H2O, with some replacement of OH by F. The specific gravity is 2·2 to 2·3, refractive index 1·514, and percentage chemical composition Al2O3 31·92, P2O5 28·63, H2O 37·93. The three strongest lines on the X-ray diffraction pattern are 9·1, 3·45, and 3·48 Å. Kingite changes to a less hydrated phase between 154° C. and 163° C., which is also considered to be a new aluminium phosphate (meta-kingite) with idealized formula Al2O3.Al(OH)3.P2O5.4H2O. The strongest lines of its X-ray diffraction pattern are at 7·4, 5·02, and 37·19 Å.

Unit cell dimensions of the hydrated aluminium phosphate–sulphate minerals sanjuanite, kribergite, and hotsonite

1989 ◽  
Vol 53 (371) ◽  
pp. 385-386 ◽  
Author(s):  
H. De Bruiyn ◽  
G. J. Beukes ◽  
W. A. Van Der Westhuizen ◽  
E. A. W. Tordiffe
Keyword(s):  
Unit Cell ◽  
X Ray Diffraction ◽  
Aluminium Phosphate ◽  
Powder Diffraction File ◽  
Cell Parameters ◽  
Cell Dimensions ◽  
Unit Cells ◽  
Diffraction Patterns ◽  
Unit Cell Dimensions ◽  
Hydrated Aluminium

AT the time when the hydrated aluminium phosphate-sulphate hotsonite (Beukes et al., 1984a) and its equally rare relative zaherite (Beukes et al., 1984b; De Bruiyn et al., 1985) were discovered near Pofadder, South Africa, very little was known about the unit cells of the other two hydrated aluminium phosphate-sulphate minerals sanjuanite and kribergite, originally described by De Abeledo et al. (1968) from Argentina and Sweden, respectively. Although the Powder Diffraction file (PDF) contains the X-ray diffraction patterns for sanjuanite and kribergite (PDF 20-47 and 20-48 respectively), they had not been indexed nor have their unit cell parameters been calculated thus far.

A new occurrence of the hydrated aluminium sulphate zaherite, from Pofadder, South Africa

1984 ◽  
Vol 48 (346) ◽  
pp. 131-135 ◽  
Author(s):  
G. J. Beukes ◽  
A. E. Schoch ◽  
H. de Bruiyn ◽  
W. A. Van der Westhuizen ◽  
L. D. C. Bok
Keyword(s):  
South Africa ◽  
Close Association ◽  
Infrared Absorption Spectrum ◽  
Type Material ◽  
Scanning Electron Micrographs ◽  
Aluminium Phosphate ◽  
Absorption Bands ◽  
Major Element Composition ◽  
Bluish Green ◽  
Hydrated Aluminium

AbstractA new occurrence of zaherite is reported from a sillimanite quarry 65 km west of Pofadder, Bushmanland, South Africa. It occurs as earthy white to light bluish-green cryptocrystalline material in narrow veins, in close association with natro-alunite and hotsonite, a new hydrated aluminium phosphate-sulphate. Scanning electron micrographs show an orientated wavy texture and tubular fibres. The optical and physical properties agree with those of the type material described from Pakistan, and it can be added that the mineral is biaxial positive with a moderate 2V and length-fast orientation. The new chemical analysis yields an ideal formula of Al12(SO4)5(OH)26·20H2O, which is identical to that of the type material. The white and light bluishgreen varieties are identical in major element composition but yielded trace Cu values of 1281 and 2408 ppm respectively. The X-ray powder diffraction pattern fits a triclinic symmetry (a 5.55, b 9.74, c 18.43Å, α 99.71°, β 89.13° γ 94.97°), and is dominated by one intense reflection at 18.12 Å, representing 001. The most important of the weak lines are (d, I, hkl): 9.56, 5, 010; 9.08, 4, 002; 4.82, 6, 01; 4.61, 8, 110; 4.56, 4, 02; 4.44, 4, 021; 3.61, 4, 1; 3.22, 8, 015. The differential thermal properties are characterized by endothermic peaks at 190, 470, and 685°C and a duplex at 880 and 910°C The infrared absorption spectrum is characterized by absorption bands centring about 905, 960, 985, 1150, 1700, and 3600 cm−1.

Open discussion

1982 ◽  
Vol 99 ◽  
pp. 605-613
Author(s):  
P. S. Conti
Keyword(s):  
Buenos Aires ◽  
Large Mass ◽  
List Type ◽  
Common Phenomenon ◽  
Open Discussion ◽  
The Stability ◽  
Ring Nebulae

Conti: One of the main conclusions of the Wolf-Rayet symposium in Buenos Aires was that Wolf-Rayet stars are evolutionary products of massive objects. Some questions:–Do hot helium-rich stars, that are not Wolf-Rayet stars, exist?–What about the stability of helium rich stars of large mass? We know a helium rich star of ∼40 MO. Has the stability something to do with the wind?–Ring nebulae and bubbles : this seems to be a much more common phenomenon than we thought of some years age.–What is the origin of the subtypes? This is important to find a possible matching of scenarios to subtypes.

Symmetric Multistep Methods Revisited: II. Numerical Experiments

1999 ◽  
Vol 173 ◽  
pp. 309-314 ◽  
Author(s):  
T. Fukushima
Keyword(s):  
Multistep Methods ◽  
Computational Time ◽  
Integration Time ◽  
Implicit Methods ◽  
Symmetric Methods ◽  
Celestial Bodies ◽  
The Stability ◽  
Predictor Corrector ◽  
Symmetric Multistep Methods ◽  
Integration Errors

AbstractBy using the stability condition and general formulas developed by Fukushima (1998 = Paper I) we discovered that, just as in the case of the explicit symmetric multistep methods (Quinlan and Tremaine, 1990), when integrating orbital motions of celestial bodies, the implicit symmetric multistep methods used in the predictor-corrector manner lead to integration errors in position which grow linearly with the integration time if the stepsizes adopted are sufficiently small and if the number of corrections is sufficiently large, say two or three. We confirmed also that the symmetric methods (explicit or implicit) would produce the stepsize-dependent instabilities/resonances, which was discovered by A. Toomre in 1991 and confirmed by G.D. Quinlan for some high order explicit methods. Although the implicit methods require twice or more computational time for the same stepsize than the explicit symmetric ones do, they seem to be preferable since they reduce these undesirable features significantly.

Uniformity of Magnification from Different Electron Microscopes

1967 ◽  
Vol 25 ◽  
pp. 32-33
Author(s):  
Godfrey C. Hoskins ◽  
V. Williams ◽  
V. Allison
Keyword(s):  
Diffraction Grating ◽  
The Other ◽  
Carbon Replica ◽  
Electron Microscopes ◽  
The Stability

The method demonstrated is an adaptation of a proven procedure for accurately determining the magnification of light photomicrographs. Because of the stability of modern electrical lenses, the method is shown to be directly applicable for providing precise reproducibility of magnification in various models of electron microscopes.A readily recognizable area of a carbon replica of a crossed-line diffraction grating is used as a standard. The same area of the standard was photographed in Phillips EM 200, Hitachi HU-11B2, and RCA EMU 3F electron microscopes at taps representative of the range of magnification of each. Negatives from one microscope were selected as guides and printed at convenient magnifications; then negatives from each of the other microscopes were projected to register with these prints. By deferring measurement to the print rather than comparing negatives, correspondence of magnification of the specimen in the three microscopes could be brought to within 2%.

Effect of Improved ThO2 Particle Dispersion in Nickel on High-Temperature Strength

1970 ◽  
Vol 28 ◽  
pp. 444-445
Author(s):  
E. R. Kimmel ◽  
H. L. Anthony ◽  
W. Scheithauer
Keyword(s):  
High Temperature ◽  
Metal Matrix ◽  
Oxide Particle ◽  
Oxide Phase ◽  
Dislocation Motion ◽  
Particle Dispersion ◽  
High Temperature Strength ◽  
Strengthening Effect ◽  
Oxide Particles ◽  
The Stability

The strengthening effect at high temperature produced by a dispersed oxide phase in a metal matrix is seemingly dependent on at least two major contributors: oxide particle size and spatial distribution, and stability of the worked microstructure. These two are strongly interrelated. The stability of the microstructure is produced by polygonization of the worked structure forming low angle cell boundaries which become anchored by the dispersed oxide particles. The effect of the particles on strength is therefore twofold, in that they stabilize the worked microstructure and also hinder dislocation motion during loading.

An Analysis of Dissociation of Molecules in a High Resolution Electron Microscope

1973 ◽  
Vol 31 ◽  
pp. 486-487
Author(s):  
Mihir Parikh
Keyword(s):  
Electron Microscope ◽  
High Resolution ◽  
Cross Sections ◽  
Resolving Power ◽  
Peak Intensity ◽  
Molecular Film ◽  
Resolution Electron ◽  
Dissociation Cross Section ◽  
High Resolution Electron Microscope ◽  
The Stability

It is well known that the resolution of bio-molecules in a high resolution electron microscope depends not just on the physical resolving power of the instrument, but also on the stability of these molecules under the electron beam. Experimentally, the damage to the bio-molecules is commo ly monitored by the decrease in the intensity of the diffraction pattern, or more quantitatively by the decrease in the peaks of an energy loss spectrum. In the latter case the exposure, EC, to decrease the peak intensity from IO to I’O can be related to the molecular dissociation cross-section, σD, by EC = ℓn(IO /I’O) /ℓD. Qu ntitative data on damage cross-sections are just being reported, However, the microscopist needs to know the explicit dependence of damage on: (1) the molecular properties, (2) the density and characteristics of the molecular film and that of the support film, if any, (3) the temperature of the molecular film and (4) certain characteristics of the electron microscope used

Formation and Structure of Casein Micelles in Lactating Mammary Tissue

1970 ◽  
Vol 28 ◽  
pp. 150-151
Author(s):  
Robert J. Carroll ◽  
Marvin P. Thompson ◽  
Harold M. Farrell
Keyword(s):  
Size Distribution ◽  
G Protein ◽  
Milk Proteins ◽  
Mammary Tissue ◽  
Colloidal System ◽  
Casein Micelles ◽  
The Stability

Milk is an unusually stable colloidal system; the stability of this system is due primarily to the formation of micelles by the major milk proteins, the caseins. Numerous models for the structure of casein micelles have been proposed; these models have been formulated on the basis of in vitro studies. Synthetic casein micelles (i.e., those formed by mixing the purified αsl- and k-caseins with Ca2+ in appropriate ratios) are dissimilar to those from freshly-drawn milks in (i) size distribution, (ii) ratio of Ca/P, and (iii) solvation (g. water/g. protein). Evidently, in vivo organization of the caseins into the micellar form occurs in-a manner which is not identical to the in vitro mode of formation.

TEM Analysis of Long-Period Polytypes in SiC—S

1976 ◽  
Vol 34 ◽  
pp. 630-631
Author(s):  
S. Shinozaki ◽  
J. W. Sprys
Keyword(s):  
Electron Diffraction ◽  
Isothermal Annealing ◽  
Tem Analysis ◽  
Long Period ◽  
Transmission Electron ◽  
Average Grain Size ◽  
High Resolution Tem ◽  
Structural Lattice ◽  
The Stability ◽  
Continuous Curves

In reaction sintered SiC (∽ 5um average grain size), about 15% of the grains were found to have long-period structures, which were identifiable by transmission electron microscopy (TEM). In order to investigate the stability of the long-period polytypes at high temperature, crystal structures as well as microstructural changes in the long-period polytypes were analyzed as a function of time in isothermal annealing.Each polytype was analyzed by two methods: (1) Electron diffraction, and (2) Electron micrograph analysis. Fig. 1 shows microdensitometer traces of ED patterns (continuous curves) and calculated intensities (vertical lines) along 10.l row for 6H and 84R (Ramsdell notation). Intensity distributions were calculated based on the Zhdanov notation of (33) for 6H and [ (33)3 (32)2 ]3 for 84R. Because of the dynamical effect in electron diffraction, the observed intensities do not exactly coincide with those intensities obtained by structure factor calculations. Fig. 2 shows the high resolution TEM micrographs, where the striped patterns correspond to direct resolution of the structural lattice periodicities of 6H and 84R structures and the spacings shown in the figures are as expected for those structures.

Sign in / Sign up

Export Citation Format

Share Document