A Mössbauer study of the effect of dithionite/citrate/bicarbonate treatment on a vermiculite, a smectite and a soil

Clay Minerals ◽  
1984 ◽  
Vol 19 (1) ◽  
pp. 85-91 ◽  
Author(s):  
T. Ericsson ◽  
J. Linares ◽  
E. Lotse
Keyword(s):  
Clay Mineral ◽  
Fine Particles ◽  
Iron Oxyhydroxide ◽  
Mössbauer Study ◽  
Iron Oxyhydroxides ◽  
X Ray ◽  
Small Domain ◽  
Particle Size Fractionation ◽  
Ultra Fine Particles

When describing clay minerals of natural origin one often has to take into account the possibility that they contain other phases, e.g. iron oxides and hydroxides which may form a ‘coating’ on the clay mineral itself or occur as physically inseparable ultra-fine particles. These iron oxyhydroxides are sometimes difficult to detect by XRD as a consequence of their very small ‘domain volumes’ (Kodama et al., 1977). The iron oxyhydroxides are normally removed chemically prior to detailed characterization of the clay mineral. Removal of iron oxyhydroxide coatings facilitates dispersion and subsequent particle-size fractionation of minerals and soils and also enhances the parallel orientation, and therefore the intensity, of basal X-ray reflections of layer-silicates.

High Resolution Replication of Organoclay Surfaces

1982 ◽  
Vol 40 ◽  
pp. 576-577
Author(s):  
W. W. Barker ◽  
W. E. Rigsby ◽  
V. J. Hurst ◽  
W. J. Humphreys
Keyword(s):  
Clay Mineral ◽  
Organic Molecule ◽  
Organic Molecules ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Naturally Occurring ◽  
Silicate Layers ◽  
Mineral Identification

Experimental clay mineral-organic molecule complexes long have been known and some of them have been extensively studied by X-ray diffraction methods. The organic molecules are adsorbed onto the surfaces of the clay minerals, or intercalated between the silicate layers. Natural organo-clays also are widely recognized but generally have not been well characterized. Widely used techniques for clay mineral identification involve treatment of the sample with H2 O2 or other oxidant to destroy any associated organics. This generally simplifies and intensifies the XRD pattern of the clay residue, but helps little with the characterization of the original organoclay. Adequate techniques for the direct observation of synthetic and naturally occurring organoclays are yet to be developed.

scholarly journals Morphological, chemical and optical absorbing characterization of aerosols in the urban atmosphere of Valladolid

2005 ◽  
Vol 5 (10) ◽  
pp. 2739-2748 ◽  
Author(s):  
S. Mogo ◽  
V. E. Cachorro ◽  
A. M. de Frutos
Keyword(s):  
Mass Fraction ◽  
Fine Particles ◽  
Aerosol Particles ◽  
Cascade Impactor ◽  
Urban Atmosphere ◽  
Coarse Particles ◽  
X Ray ◽  
Illumination System ◽  
Inverse Power Law

Abstract. Samples of atmospheric aerosol particles were collected in Valladolid, Spain, during the winter of 2003-2004. The measurements were made with a Dekati PM10 cascade impactor with four size stages: greater than 10 µm, between 2.5 to 10 µm, 1 to 2.5 µm and less than 1 µm. The size and shape of the particles were analyzed with a scanning electron microscope (SEM) and elemental analysis was done with an energy dispersive x-ray analysis (EDX). We present an evaluation by size, shape and composition of the major particulate species in the Valladolid urban atmosphere. The total aerosol concentration is very variable, ranging from 39.86 µg·m-3 to 184.88 µg·m-3 with the coarse particles as the dominant mass fraction. Emphasis was given to fine particles (<1 µm), for which the visible (400 nm to 650 nm) light absorption coefficients were measured using the integrating plate technique. We have made some enhancements in the illumination system of this measurement system. The absorption coefficient, σa, is highly variable and ranges from 7.33×10-6 m-1 to 1.01×10-4 m-1 at a wavelength of 550 nm. There is an inverse power law relationship between σa and wavelength, with an average exponent of -0.8.

Characterization of “Stickies” Polymeric Contaminants in Recycle Pulp Slurries by Optical Fluorescence and Scanning Electron Microscopy.

1997 ◽  
Vol 3 (S2) ◽  
pp. 1247-1248
Author(s):  
R. M. Fisher ◽  
J. Holbery ◽  
Barbara Reine
Keyword(s):  
Electron Microscopy ◽  
Fine Particles ◽  
Polymeric Materials ◽  
Measuring Instruments ◽  
Paper Machine ◽  
X Ray ◽  
Optical Fluorescence ◽  
Thermal Analysis Techniques ◽  
Physical And Chemical

A major problem now hampering increased recycling of old cardboard containers (OCC), is the presence of significant amounts of polymeric materials such as adhesives, tapes, labels and wax which enter the pulp process stream along with the cardboard and paper that was collected for recycling. Many of these materials contain very fine particles of inorganic fillers and pigments. These various contaminant constituents combine in some, as yet unknown, manner to form an extremely gummy material that deposits on paper machine surfaces and sticks tenaciously (hence the term “Stickies”). The sticky blobs are very difficult to remove and increases machine downtime and maintenance costs as well as causing blemishes on the finished container board product Light optical image analysis, UV fluorescence, FTIR and electron microscopy are being used in consort with particle size measuring instruments, TGS and DSC thermal analysis techniques, FTIR infra-red spectroscopy as well as XRF (x-ray fluorescence spectroscopy ), XPS (x-ray photo emission spectroscopy) and classical contact angle determination methods as part of a broad program to characterize the physical and chemical nature of stickies in pulp slurries with the goal of removing them or alleviating their pronounced tendency to deposit on machinery and paper products.

Synthesis and characterization of a silylated Brazilian clay mineral surface

2014 ◽  
Vol 68 (7) ◽  
Author(s):  
Márcia Silva ◽  
Saloana Gomes ◽  
Maria Fonseca ◽  
Kaline Sousa ◽  
José Espínola ◽  
...  
Keyword(s):  
Clay Mineral ◽  
Solid State Nmr ◽  
Textural Properties ◽  
Hydroxyl Groups ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Diffraction Patterns ◽  
Trimethoxy Silane

AbstractClay mineral containing kaolinite, illite and montmorillonite was organofunctionalized with silylating agents: (3-aminopropyl)triethoxysilane, 3-[2-(2-aminoethylamino)ethylamino]propyl-trimethoxysilane and (3-mercaptopropyl)trimethoxy-silane, to yield three hybrids labelled Clay1, Clay2 and Clay3, respectively. These solids were characterized using elemental analysis, thermogravimetry, X-ray diffractometry, infrared spectroscopy, scanning electron micrograph, and 29Si and 27Al solid state NMR. Immobilized quantities of the organic groups were 0.66 mmol g−1, 0.48 mmol g−1 and 0.88 mmol g−1 for Clayx (x = 1–3), respectively. X-ray diffraction patterns confirmed the immobilization of silanes onto the surface without changes in the textural properties of the clay mineral as noted from the SEM images. Spectroscopic measurements were in agreement with the covalent bonding between the silanes and the hydroxyl groups deposited on the surface. The new hybrids were utilized as adsorbents of cobalt in aqueous solution, with retention values of 0.78 mmol g−1, 1.1 mmol g−1 and 0.70 mmol g−1 for Clayx (x = 1–3), respectively.

Synthesis and Characterization of Nanocrystalline CeO2

2006 ◽  
Vol 306-308 ◽  
pp. 1103-1108
Author(s):  
Abdul Hadi ◽  
Iskandar Idris Yaacob
Keyword(s):  
Fine Particles ◽  
Gas Adsorption ◽  
Mesoporous Structure ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Face Centered ◽  
Adsorption Desorption

Nanocrystalline CeO2 has been synthesized at room temperature using water-in-oil (w/o) microemulsion technique. The structure and properties of the nanocrystalline CeO2 were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and gas adsorption desorption measurement. XRD results showed the synthesized CeO2 has a face centered cubic structure with crystallite size of about 5.2 nm. TEM observation also indicated the presence of nanometer sized particles of CeO2. Coarser particles were also observed due to agglomeration. Gas adsorption desorption isotherms showed the behavior of fine particles with mesoporous structure.

Internal Dislocation Density in Deformed GlidCop from X-Ray Line Profile Analysis

2021 ◽  
Vol 1016 ◽  
pp. 1223-1228
Author(s):  
Mutsumi Sano ◽  
Sunao Takahashi ◽  
Ayumi Shiro ◽  
Takahisa Shobu ◽  
Kengo Nakada
Keyword(s):  
Dislocation Density ◽  
Line Profile ◽  
Fine Particles ◽  
Profile Analysis ◽  
Compressive Strain ◽  
Strain Range ◽  
Line Profile Analysis ◽  
X Ray ◽  
Dislocation Densities ◽  
Ultra Fine Particles

Dislocation densities of GLIDCOP®, dispersion-strengthened copper with ultra-fine particles of aluminum oxide, were evaluated by employing the X-ray line profile analysis using the modified Williamson-Hall and modified Warren-Averbach methods. X-ray diffraction profiles for GlidCop samples with compressive strains applied at 200oC were measured with synchrotron radiation. The dislocation densities of GlidCop with compressive strain ranging from 0.6 to 4.3% were in the order of 3.2 × 1014–5.8 × 1014 m-2. The dislocation density increased with increasing the compressive strain within the measured strain range.

Structure and Properties of Superfine Coating on Cast Steel by Electro-Spark Deposition

2011 ◽  
Vol 189-193 ◽  
pp. 1018-1022
Author(s):  
Yu Xin Gao ◽  
Zhi Gang Fang ◽  
Jian Sheng Wang
Keyword(s):  
Sliding Wear ◽  
Fine Particles ◽  
Steel Substrate ◽  
Cast Steel ◽  
Wear Test ◽  
Structure And Properties ◽  
X Ray ◽  
Surface Performance ◽  
Ultra Fine Particles ◽  
Scanning Electron

Superfine coatings have been attempted to prepare by Electro-spark deposition (ESD) on cast steel substrate. The microstructures and properties of the coating were investigated by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and microhardness tester. The results show that ultra-fine particles prevail in the coating. The primary phases of the coating contain Fe3W3C, Co3W3C, Si2W and W2C. Its average microhardness reaches 1511.75 HV. The results of abrasive test demonstrated that the coating had an excellent sliding wear resistance because the superfine particles distributed dispersedly in the coating increased the resistance to micro-cutting and plowing during the wear test, which effectively improves the surface performance of cast steel substrate.

Microstructure and Properties of Electrospark Deposition Coating on Die Steel

2011 ◽  
Vol 291-294 ◽  
pp. 188-191
Author(s):  
Yu Xin Gao ◽  
Cheng Zhao
Keyword(s):  
Sliding Wear ◽  
Fine Particles ◽  
Steel Substrate ◽  
Wear Test ◽  
Electrospark Deposition ◽  
Die Steel ◽  
X Ray ◽  
Surface Performance ◽  
Ultra Fine Particles ◽  
Scanning Electron

Superfine coatings have been prepared by Electro-spark deposition (ESD) on die steel substrate with WC-8Co electrode. The microstructures and abrasion performance of the coating were investigated by X-ray diffractometer (XRD), scanning electron microscopy (SEM) and microhardness tester. The results show that ultra-fine particles prevail in the coating. The primary phases of the coating contain Fe3W3C, Co3W3C, Fe7W6 and W2C. The maximum microhardness reaches 1432.5 HV0.3. The results of abrasive test demonstrated that the coating had an excellent sliding wear resistance because the superfine particles distributed dispersedly in the coating increased the resistance to micro-cutting and plowing during the wear test, which effectively improves the surface performance of die steel substrate.

scholarly journals Morphological, chemical and optical absorbing characterization of aerosols in the urban atmosphere of Valladolid

2005 ◽  
Vol 5 (3) ◽  
pp. 3921-3957 ◽  
Author(s):  
S. Mogo ◽  
V. E. Cachorro ◽  
A. M. de Frutos
Keyword(s):  
Fine Particles ◽  
Visible Spectrum ◽  
Urban Atmosphere ◽  
Particle Sizes ◽  
Absorption Coefficients ◽  
X Ray ◽  
Illumination System ◽  
Short Time ◽  
Individual Particles

Abstract. Aerosol samples were collected from the Valladolid (Spain) atmosphere during 2003–2004 winter using a Dekati PM10 cascade impactor which allows to discriminate four level of particle sizes: greater than 10 µm, between 10 and 2.5, from 2.5 to 1 and less than 1 µm. The size and shape of the aerosol deposits were analyzed by means of individual particles through scanning electron microscope (SEM) technique. Additionally an energy dispersive X-ray analysis (EDX) was performed enabling elemental analysis of a large number of individual particles in a relatively short time. We present a classification in size, shape and composition of the major particulate species present in the Valladolid urban atmosphere. The aerosol concentration is very variable during winter, ranging from 39.86&amp;nbspµg·m−3 to 184.88 µg·m−3 with coarse particle as dominant fraction. Emphasize was given to fine particles, behind 1 µm, for which the visible (from 400 nm to 650 nm) light absorption coefficients were measured using the integrating plate technique. We have made some enhancements relative to the illumination system in the well known integrating plate method, for the absorption coefficients determination. The absorption coefficient ranges from 7.33×10−6 m−1 to 1.01×10−4 m−1 for the 550 nm wavelength. Its visible spectrum decreases with wavelength with greater slope for greater σ values.

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