The interaction of telone with acid and base saturated montmorillonite furnished adsorption isotherms which possessed combined features of H (high affinity) and C (linear rising) class isotherms; a fall in pH, an increase in electrical conductivity and formation of chloride ions. The observations were indicative of a process of chemisorption, both at the planar and lateral sites of montmorillonites, followed by penetration and swelling of the substrate micropores with telone. A reaction mechanism for the process of chemisorption has been proposed.

Varieties of kaolin, a rock, may be classified geologically, mineralogically, crystallographically, genetically, texturally, morphologically, by industrial use, and in other ways which are desired. In this paper, the first-order of classification used is geological, i.e., transported and residual, after which other categories are used as subdivisions.

Scan electron micrographs, SEM, of the textures of kaolin show that distinctive textures characterize the several categories of classification. Varieties in texture of kaolin include similarities to those typical of sedimentary, igneous and metamorphic rocks. Because word descriptions of the textures are inadequate in comparison to pictures of them, the reader is referred to the micrographs.

SEM's illustrate differences between kaolins which were transported, formed, or deposited from solution, a colloidal phase, or as orthodox clastic particles. The parent source of kaolin deposited, or “grown,” from solution may be difficult to ascertain. It is suggested that the total role of solution work in kaolin petrology can be more important than has ordinarily been credited.

The microstructures of impact-compacted kaolinite and illite clays, after drying, were investigated by pore size-distribution measurements, X-ray orientation determinations, and scanning electron microscopy. Clays compacted on the dry side of the optimum moisture content exhibited a domain structure with adjacent domains largely separated by micrometer-size interdomain voids; clays compacted at or above the optimum moisture content showed a more nearly massive structure, large interdomain voids being absent. Parallel orientation was observed within domains, but neighboring domains were generally tilted with respect to each other. In kaolinite compacted on the wet side of optimum, regions of local parallel orientation could be identified at high magnification as domain units. A significant volume of 200 Å–800 Å dia. pores in this clay was identified with spaces observed between the kaolinite plates within domains, for samples compacted both on the wet and dry sides of optimum. The subdomain structure was tentatively classified as “intergrown” in character. (001)/(020), (002)/(020), (001)/(060), and (002)/(060) orientation indices were calculated for the compacted kaolinite and compared with analogous measurements for fully-random and fully-oriented specimens of the same clay. The results indicated only a small degree of preferential orientation normal to the axis of compaction, with little difference between samples compacted either wet or dry of optimum. These results were consistent with scanning electron microscope interpretations, which suggested that the domains did not appear to orient themselves significantly under the influence of the compaction employed.

The idealized symmetry of kaolinite-type minerals (1:1 phyllosilicates) is analysed in detail. They can be considered as OD-structures consisting of three kinds of OD-layers. Each of them, taken separately, possesses higher symmetry than their combination. This explains the well-known tendency of kaolinite-type minerals to form a wide variety of ordered and disordered polytypes as well as twins. The possible stacking sequences result from the different kinds of pairs of kaolinite layers which are derived for dioctahedral, trioctahedral as well as ‘monoctahedral’ kaolinite-type minerals, the latter being defined as those in which the three octahedral positions are occupied by three different cations or two different cations and a void. The analysis makes use of a simple symbolism and a simplified pictorial representation.

A brief summary of the most important terms and definitions of the theory of OD-structures is given in an Appendix.

Fe57 Mössbauer spectroscopy has been used to determine the nature of iron-containing minerals in Lower Greensand samples from an experimental lysimeter at Uffington, Oxfordshire, both before and after a three-year irrigation with a synthetic heavy metal leachate. Analysis of the spectra measured at 300°, 77°, and 4.2°K and at 4.2°K in an applied field of 45 kOe shows that iron is present in the uncontaminated sandstone in fine-grained goethite (α-FeOOH) and glauconite. In the irrigated samples iron is precipitated as a fine-grained ferric hydroxide gel having values for the hyperfine field at 4.2°K of 435 and 470 kOe. The stability of the gel over the three-year period of irrigation may be explained by surface energy considerations.

Vermiculite (Libby, Mont.) was ground in a Waring blender in a 1 m NaCl solution and, after removal of excess electrolyte, the clay fraction was separated by sedimentation. The clay was predominantly vermiculite: X-ray diffraction patterns of Ca-saturated and oriented specimens showed an intense and sharp 15 Å and a weak 25 Å diffraction maxima and their integral orders. The intensity of the 25 Å reflection, attributed to regularly interstratified layers of vermiculite (15 Å) and mica (10 Å), was less than 20% of the 15 Å peak.

Additions of varying amounts of potassium or cesium, ranging from 10% to 100% of exchange capacity, to Ca-saturated clay showed that the collapse of the vermiculite lattice proceeds through a 1:1 regular interstratification of a 15 Å and a 10 Å lattice. Successive additions increased the 25 Å diffraction peak at the expense of the 15 Å reflection until the entire sample was interstratified. Further additions of K (or Cs) reduced the intensity of the 25 Å reflection and produced a 10 Å reflection until the entire sample was collapsed to 10 Å and no 25 Å reflection was recorded. These observations point out that under certain environmental conditions, the diagenetic formation of micas from vermiculite may proceed through an interstratification of the two in a manner analogous to weathering of biotite to vermiculite through an interstratified stage.

One-dimensional Fourier synthesis from the intensities of the 00ℓ diffraction maxima of the interstratified mixture was carried out. In addition, a mechanism for the formation of the interstratified mixture was postulated: the replacement of Ca by K (or Cs) in one layer reduces the effective negative charge on the adjacent layer. Consequently, the K cannot replace the Ca in this but replaces the Ca in the next layer forming the interstratified mixture.

Braidwood Management, Inc. v. Becerra challenges the Affordable Care Act free preventive coverage guarantee. Community health centers serve over 30 million residents of medically underserved urban and rural communities. Their limited federal grant funding makes them reliant on insurance revenue for their operations, Medicaid and subsidized marketplace coverage in particular, both of which are implicated by the case. To understand these implications, we developed an analytic model that crosswalks the preventive services potentially affected by Braidwood and the preventive care that all health centers must furnish. Of the 193 preventive services now covered under the guarantee, only forty-eight would survive were the Braidwood plaintiffs to prevail. In underserved communities, health centers are a principal source of the nearly 150 affected services, as evidenced by the care they are required to furnish under federal law, the quality metrics they are expected to meet, and the health diagnoses and treatments identified in federal performance reporting requirements. Thus, the impact on access, quality, patient health, and health center finances and care capability will likely be substantial.

The influence of Al on the products formed by aerial oxidation at pH 5.5-7 and 20°C of Fe(II) chloride, sulfate and carbonate solutions, was examined. In all cases Al at levels Al/Al + Fe = 0.09−0.30 inhibited the formation of y phases (lepidocrocite and maghemite) in favor of goethite under conditions where, in the absence of Al, these y phases formed. The influence of Al in these laboratory studies was supported by field observations.

At higher levels of Al, ferrihydrite formation was favored. This effect of Al was seen to be the result of a slowing down in the hydrolysis/oxidation rate of the Fe(II) system.

The presence of Al not only changed the direction of mineral formation, but also caused the formation of Al substitued goethites which resembled in particle size and morphology the natural aluminiferous goethite extracted from a soil.

Scan electron micrographs are shown of (1) kaolinite and dickite which crystallized from solution within cavities, (2) kaolinite weathered from clastic primary silicate material, (3) residual kaolinite from primary silicate rock, (4) kaolinite above and below a basal unconformity on granitic rock, and (5) hydrothermally altered kaolinite. The texture of kaolin reflects the environment in which the clay was formed.

Euhedral crystals of kaolin minerals characterize cavity fillings. The weathering environment produces large crystal flakes of kaolinite, expanded books, mats of elongates, high porosity, and low bulk density (less than 2.0). The hydrothermal environment produces smaller crystals, singles, sheaves and packets of crystals, low porosity and high bulk density (2.0 and above).

The interrelationships of genetic environment of kaolin minerals and accompanying texture are discussed in light of available geochemical information.

This study was an investigation of the effects of sesquioxide constituents on some mineralogical and physiochemical properties of a Panamanian latosol.

Latosols are soils characterized by high concentrations of iron and aluminum oxides and a general absence of free silica and alkaline earths.

X-ray diffraction studies revealed sesquioxide coatings existed on the surfaces of the clay minerals. Mineralogically, the soil was composed of kaolin, amorphous minerals, hydrated iron and aluminum oxides, free silica, quartz grains, and magnetite. The results of DTA data suggested the presence of amorphous colloids in the soil. This suggestion was subsequently confirmed by selective dissolution analysis which revealed the unexpected presence of 17% amorphous silica in the coarse clay size fraction. Grain size analysis and scanning electron microscopy studies showed that the clay minerals are probably agglomerated by the sesquioxides into silt size clusters. CEC values obtained were primarily attributed to the amorphous colloids rather than the crystalline clay minerals because the sesquioxides probably partially blocked the exchange sites of the clays.

Removal of the iron and aluminum oxides by sodium dithionite citrate-bicarbonate procedures (Mehra and Jackson, 1960), (a) sharpened and exposed previously “masked” X-ray diffraction peaks, (b) disaggregated the clay clusters producing greater amounts of clay size particles, and (c) altered the Cation Exchange Capacity (CEC) and water retention characteristics of the soil constituents.

This investigation demonstrated that amorphous silica and iron and aluminum oxides greatly influence the properties of this latosol by coating and aggregating the clay minerals. These sesquioxide coatings suppress the ordinary behavioral characteristics of the indigenous clay minerals and consequently the observed behavior of the soil is dominated by the amorphous constituents.

This investigation was designed to integrate the quick-freeze technique for ion diffusion with two computer programs to permit the simultaneous measurement and calculation of the diffus-ivity of a variable number of ions in heteroionic soil system. Kaolinite clay was prepared so as to have the following percentage saturations of the CEC, Sr2+65, Mg2+15, Rb+10, Na+5 and H+5. A quadruplicate radioisotope tag consisting of 85Sr, 28Mg, 86Rb, and 22Na was used to measure the diffusivity of each ion. The complex spectra were resolved by use of Schonfeld’s revised Alpha-M computer program. A probit-transformation procedure was formulated into a computer program to enable the calculation of each diffusion coefficient. These programs are described and illustrated with the diffusivity of 86Rb in kaolinite clay.

An electro-optic birefringence technique was employed to study the orientation mechanism of montmorillonite in an electric field. The instantaneous reversal of the field polarity produced evidence of a low voltage permanent dipole and a high voltage induced dipole. This technique was used to study theeffect ofelectrolyte concentration on the rotational diffusion coefficient, a measure of the rate at which the particles rotate or relax, within the solution, from a preferred orientation. Thus, a measure of the immediate environment of the particles was obtained that is not an average effect for the whole system, yet allows for the full development of the clay-cation-water interactions under the experimental conditions. It was found that particle rotation could be accounted for using the measured particle size and normal water viscosity only when the double layer was fully developed, with no free ions or other perturbations. As soon as perturbations were applied, either by adding salts or applying an electric field, the measured particle size and normal viscosity would not account for the data. Either the rotating moiety has to be larger, that is, be a particle plus a water hull, or the viscosity greater, or in some cases both.

The electron spin resonance of some structural Fe3+ for montmorillonites having low Fe3+ content, is perturbed by electrostatic interaction between exchange cations and structural charge sites. The position of charge centers of organic and inorganic cations in the interlayer can thus be determined at various levels of solvation. Dielectric media between the silicate layers lower the electrostatic attraction between the silicate and the exchange cations. The silicate charge appears to be partially delocalized on structural oxygen atoms as shown by electron spin resonance and i.r. spectroscopy. There is also evidence that divalent exchange cations on dehydrated montmorillonites cause hydrolysis of water; the protons so produced migrate to structural charge sites.