scholarly journals The change in the surface characteristics of amorphous clay mineral separated from Kanuma pumice layer by treatment with aqueous NaOH solution.

1989 ◽  
pp. 1949-1956 ◽  
Author(s):  
Hiroshi TOHGOH ◽  
Hajime TANAKA ◽  
Yuhkei TAKASAKI ◽  
Atsushi ENDOH
Keyword(s):  
Clay Mineral ◽  
Surface Characteristics ◽  
Naoh Solution

Effect of alkali treatment on physical and mechanical properties of bamboo short fibers

2021 ◽  
Vol 21 (3) ◽  
pp. 535-543
Author(s):  
Suhas Yeshwant Nayak ◽  
K. Rajath Shenoy ◽  
Rashmi Samant ◽  
Praneeth P. Sarvade ◽  
Satish Shenoy B ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Alkali Treatment ◽  
Fiber Surface ◽  
Physical And Mechanical Properties ◽  
Surface Characteristics ◽  
Tensile Tests ◽  
Short Fibers ◽  
Duration Of Treatment ◽  
Surface Irregularities ◽  
Naoh Solution

Bamboo (Arundinaria clarkei) short fibers were treated with 6% conc. NaoH solution for five different durations viz. 3 h, 6 h, 9 h, 12 h and 24 h. Effect on physical properties like diameter and density were studied. Fibers were examined using Scanning Electron Microscope (SEM) to study the effect of alkali treatment on its surface characteristics. Single fiber tensile tests were conducted to assess the tensile strength of the fibers. Comparative study of the SEM micrographs indicated removal of outer layer with the surface irregularities becoming more prominent with increasing duration. The fiber surface was scanned using an Atomic Force Microscope (AFM) to quantify the increase in surface roughness with alkali treatment. Tests results showed positive effect on the strength till 6 h beyond which the tensile strength was observed to reduce. Fourier Transform Infrared (FTIR) spectroscopy results indicated reduction in content of holocellulose along with hemicellulose, lignin and cellulose which explains the variation in tensile strength with increasing duration of treatment.

Clay minerals for nanocomposites and biotechnology: surface modification, dynamics and responses to stimuli

Clay Minerals ◽  
2012 ◽  
Vol 47 (2) ◽  
pp. 205-230 ◽  
Author(s):  
H. Heinz
Keyword(s):  
Surface Modification ◽  
Clay Minerals ◽  
Clay Mineral ◽  
Self Assembly ◽  
Functional Materials ◽  
Surface Characteristics ◽  
Mineral Surface ◽  
Thermal Transitions ◽  
Wide Range ◽  
Potential Applications

AbstractClay minerals find a wide range of application in composites, paints, drilling liquids, cosmetics, and medicine. This article reviews chemical and physical properties of natural and organically modified clay minerals to understand the nanometre-scale structure, surface characteristics, and application in functional materials. The relation between fundamental properties and materials design is emphasized and illustrated by examples. The discussion comprises the following: an overview; surface structure and cation density; solubility and solubility reversal by surface modification; the degree of covalent and ionic bonding represented by atomic charges; the distribution of metal substitution sites; measurements and simulations of interfacial properties at the nanometre scale; self-assembly, packing density, and orientation of alkylammonium surfactants on the clay mineral surface; the density and chain conformation of surfactants in organic interlayer spaces; the free energy of exfoliation in polymer matrices and modifications by tuning the cleavage energy; thermal transitions, diffusion, and optical responses of surfactants on the mineral surface; elastic moduli and bending stability of clay layers; and the adsorption mechanism of peptides onto clay mineral surfaces in aqueous solution. Potential applications in biotechnology and other future uses are described.

scholarly journals Microbial Key Players Involved in P Turnover Differ in Artificial Soil Mixtures Depending on Clay Mineral Composition

2020 ◽  
Author(s):  
Irina Tanuwidjaja ◽  
Cordula Vogel ◽  
Geertje J. Pronk ◽  
Anne Schöler ◽  
Susanne Kublik ◽  
...  
Keyword(s):  
Mineral Composition ◽  
Clay Mineral ◽  
Soil Surface ◽  
Surface Characteristics ◽  
P Uptake ◽  
Inorganic Pyrophosphatase ◽  
P Availability ◽  
Alkaline Phosphatases ◽  
Microbial Potential ◽  
Clay Mineral Composition

Abstract Nutrient turnover in soils is strongly driven by soil properties, including clay mineral composition. One main nutrient is phosphorus (P), which is known to be easily immobilized in soil. Therefore, the specific surface characteristics of clay minerals might substantially influence P availability in soil and thus the microbial strategies for accessing P pools. We used a metagenomic approach to analyze the microbial potential to access P after 842 days of incubation in artificial soils with a clay mineral composition of either non-expandable illite (IL) or expandable montmorillonite (MT), which differ in their surface characteristics like soil surface area and surface charge. Our data indicate that microorganisms of the two soils developed different strategies to overcome P depletion, resulting in similar total P concentrations. Genes predicted to encode inorganic pyrophosphatase (ppa), exopolyphosphatase (ppx), and the pstSCAB transport system were higher in MT, suggesting effective P uptake and the use of internal poly-P stores. Genes predicted to encode enzymes involved in organic P turnover like alkaline phosphatases (phoA, phoD) and glycerophosphoryl diester phosphodiesterase were detected in both soils in comparable numbers. In addition, Po concentrations did not differ significantly. Most identified genes were assigned to microbial lineages generally abundant in agricultural fields, but some were assigned to lineages known to include oligotrophic specialists, such as Bacillaceae and Microchaetaceae.

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.

Medial Smooth Muscle Cell Proliferation in the Balloon Injured Rabbit Aorta: Effect of a Thiazole Compound with Platelet Inhibitory Activity

1984 ◽  
Vol 51 (01) ◽  
pp. 075-078 ◽  
Author(s):  
R G Schaub ◽  
C A Simmons
Keyword(s):  
Smooth Muscle ◽  
Platelet Aggregation ◽  
Balloon Catheter ◽  
Rabbit Aorta ◽  
Surface Characteristics ◽  
Inhibitory Effect ◽  
Lesion Size ◽  
Blue Staining ◽  
Morphologic Characteristics ◽  
Time Period

SummaryTwenty-seven adult male New Zealand rabbits (3–4 kgs) were used in this study. Six rabbits received vehicle, 3 groups of 6 each received doses of 4,5-bis(p-methoxyphenyl)-2-(trifluoromethyl)- thiazole, (U-53,059), at 0.3 mg/kg, 3.0 mg/kg and 30.0 mg/kg/day respectively. Drug and vehicle doses were given orally each day starting 3 days before balloon injury and continuing for the entire 2 week time period. Three rabbits were used as nontreated sham controls. In the vehicle and U-53,059 treated groups aortae were denuded of endothelial cells by balloon catheter injury. Two weeks after injury platelet aggregation to collagen was measured and the aortae removed for analysis of surface characteristics by scanning electron microscopy and lesion size by morphometry. All doses of U-53,059 inhibited platelet aggregation. The 3.0 and 30.0 mg/kg groups had the greatest inhibitory effect. All balloon injured aortae had the same morphologic characteristics. All vessels had similar extent and intensity of Evan’s blue staining, similar areas of leukocyte/platelet adhesion, and a myointimal cell cover of transformed smooth muscle cells. The myointimal proliferative response was not inhibited at any of the drug doses studied.

Photocatalytic activity of TiO2 synthesized by anodization and anodic spark deposition

MRS Advances ◽  
2020 ◽  
Vol 5 (61) ◽  
pp. 3141-3152
Author(s):  
Alma C. Chávez-Mejía ◽  
Génesis Villegas-Suárez ◽  
Paloma I. Zaragoza-Sánchez ◽  
Rafael Magaña-López ◽  
Julio C. Morales-Mejía ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Surface Characteristics ◽  
Amorphous Solids ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalytic Activities ◽  
Anodic Spark Oxidation ◽  
Porous Surfaces ◽  
Scanning Electron

AbstractSeveral photocatalysts, based on titanium dioxide, were synthesized by spark anodization techniques and anodic spark oxidation. Photocatalytic activity was determined by methylene blue oxidation and the catalytic activities of the catalysts were evaluated after 70 hours of reaction. Scanning Electron Microscopy and X Ray Diffraction analysis were used to characterize the catalysts. The photocatalyst prepared with a solution of sulfuric acid and 100 V presented the best performance in terms of oxidation of the dye (62%). The electric potential during the synthesis (10 V, low potential; 100 V, high potential) affected the surface characteristics: under low potential, catalyst presented smooth and homogeneous surfaces with spots (high TiO2 concentration) of amorphous solids; under low potential, catalyst presented porous surfaces with crystalline solids homogeneously distributed.

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