Alternating mica-like and smectite-like layers of rectorite give rise to periodically varying contrast in 10-Å lattice fringes, yielding a periodicity of 20 Å in a transmission electron microscopic study. Expansion of rectorite using dodecylamine hydrochloride yields a three-layer repeat of thickness 32–35 Å, consisting of a basic 20-Å unit, identical to that in images of collapsed, dehydrated rectorite, and a 12-15-Å thick, intercalated organic layer.

Thin packets of layers derived by grinding the sample are only 20 Å thick, or multiples thereof. Serrated edges of rectorite grains likewise have steps 20 Å in height, implying that mechanical cleavage occurs readily along the weakly bonded, smectite-like interlayers. The “fundamental” 20-Å unit is proposed to be compositionally centered on an interlayer bounded by two identical T-O-T layers, each of which has compositionally different tetrahedral sheets. Such structural considerations suggest that resultant 20-Å units (“rectorite units”) are unique in structure and chemistry relative to true illite. These results further imply that grinding and other treatment of coherent crystals of clay minerals may produce individual unit layers. Moreover, when coupled with size-separation, such treatment may yield X-ray powder diffraction data that reflect reconstituted layer sequences.

Spherical kaolinite has been synthesized for the first time from noncrystalline aluminosilicate material in hydrothermal experiments conducted between 150° and 250°C and under autogenous vapor pressure. Spherules, whose mean diameters depended on growth conditions (0.1–0.6 μm), were formed surrounding the noncrystalline aluminosilicate in all products of 150° and 200°C runs and coexisted with platy or lath-shaped kaolinite in the products of 250°C runs. The estimated percentages of spherules in the products increased from about 1% in the 150°C-15 days product to about 74% in 200°C-8 days product, and decreased from about 21% in 250°C-2 days product to 0% in 250°C-8 days product. Lattice images by high-resolution electron microscope indicated that the spherules consisted of nearly concentric stackings of layers with a unit spacing of 7Å, which were sectored by radiating boundaries. The mean chemical composition of the spherules (Al2O3/SiO2 = 0.58) analyzed by the analytical electron microscope is similar to that of kaolinite (Al2O3/SiO2 = 0.5). Even in the case of the product abundant in spherule (200°C-8 days), X-ray powder diffraction patterns of the wetted products, e.g., of the 200°C-8 day run, showed the 7.14-Å (001) reflection of kaolinite. The 020 reflection was broad, indicating the existence of abundant (001) layer displacements. The b axis (8.94 Å) were within the kaolinite range (8.93–8.94 Å). No infrared absorption peaks were observed at 3550 cm−1 which would correspond to halloysite. The differential thermal analysis slope ratios of the endothermic peak at about 550°C (1.4–2.3) were in the kaolinite range (0.78–2.39).

Dehydration-induced luminescence (DIL), the emission of light from a clay paste upon dehydration, was characterized experimentally for a colloidal kaolinite. The relationship between total photon count of the emitted light and film thickness is linear up to a thickness of 30 μm. The photon emission was obtained over a critical range of water contents (25-60%) of the oven-dry clay, and the kinetics of photon emission was presumed to be closely associated with the kinetics of film dehydration. Whether drying proceeded throughout the bulk or via a moving front was undetermined, but in either mode it was preceded by the formation of a thin dry film at the interface with the atmosphere. Grinding of the kaolinite for several minutes by mortar and pestle before paste preparation resulted in an overall increase of photon emission compared to unground kaolinite and in the formation of more than one emission peak, as well as a prolongation of the light emission. This effect on the kinetics of light emittance was observed for about two months after the application of the mechanical stress and suggests a means of detecting the mechanical stress history of a clay.

An estimate was made of the spectral characteristics of the emitted light using optical filters and by incorporating tryptophan and salicylic acid into the kaolinite paste where they acted as fluorescent probes. The latter technique shifted the frequency of the light emitted by the kaolinite from the ultraviolet to the visible range where it was less effectively reabsorbed. The first method showed that the wavelengths of 97% of the emitted light was <460 nm and that 75% of the light had wavelengths <410 nm. The second method showed that the total intensity of DIL increased in the presence of fluorescence molecules, suggesting that the emittance was in the ultraviolet range.

Three methods were investigated to separate palygorskite from mixtures of clay minerals in soils and sediments. The methods were based on the hydrophobic properties of a dodecylammonium-smectite complex and used the <0.2-μm fractions of reference palygorskites that contained smectite and sepiolite impurities. Palygorskite was separated from dodecylammonium-clay complexes by: (1) selective dispersion of palygorskite in H2O; (2) selective extraction of palygorskite by a water:decanol phase separation; and (3) selective extraction of palygorskite by a water: nitrobenzene phase separation. Whereas all three methods resulted in palygorskite separation, selective dispersion was the simplest and employed the more desirable reagents. Small amounts of relatively pure palygorskite in the <0.2-μm fractions were concentrated from palygorskite-containing clays from Texas, Saudi Arabia, and Libya as shown by X-ray powder diffraction and transmission electron microscopy data. A sepiolite impurity in the Georgia palygorskite was concentrated with the palygorskite. Hydrolysis of the dodecylammonium-smectite complex was suggested by the decrease in d-spacing of some samples after the extensive washing necessary for dispersion. An appreciable amount of the fibrous mineral was intimately associated with layer silicates and could not be separated.

Direct water-activity measurements were made for calcium-smectite-CaCl2 mixtures. The samples used were prepared by high-pressure filtration and had water contents <0.60% by weight of clay. For deionized water, the water activity (aw) ranged between 1 and 0.4 and was independent of the pressure history of the clay cake. Good agreement was found with the results of an adsorption isotherm. Samples were also prepared in 1,3, and 5 M CaCl2 solutions. The final concentration of chloride present in the cakes was measured: substantial anion exclusion was observed. The water activity of the clay-salt mixtures depended on both the water content and the concentration of CaCl2. The data can be well represented by the expression aw = min(aw0, aw*c × aw*s), where aw0 is the water activity of the brine used to prepare the cake, and aw*c and aw*s are water activities calculated for clay (in absence of salt) and salt (in absence of clay), respectively. The compaction and swelling behavior of a core of the same Ca-smectite was also investigated for pressures (P) between 0.5 and 800 bar. In two compaction-swelling cycles total recovery of the void ratio (e) was observed with, however, large hysteresis in the relationship between e and P. The osmotic pressure developed in the core at equilibrium, evaluated using the water-activity data, was intermediate between the compaction and swelling pressures. Apparently, another force, Pm, linked to irreversible changes in the structure of the matrix was contributing to the resistance to compaction. Pm values agreed with literature results for Ca-smectite suspensions.

These few pages will attempt to analyze the relationships created in the chronically delirious person between himself and his own biography, such as he knows and has experienced it, to which he attaches himself and which dominates him without his knowing it. A few remarks to clarify our vocabulary before getting into the development of this question. We prefer the expression “chronic deliria“, in the plural, to the word “psychosis”, used in the singular. The former term is clinical, and therefore empirical, whereas the second derives from theories; and, especially, the former does not immediately imply a unity of process as opposed to the effective diversity of semiotic appearances. Moreover, the nominal adjective “psychotic“ runs the risk of both clandestinely bringing in hidden presuppositions and of re-establishing the old presumed unity with mental alienation, which had, indeed, been exorcised by J. P. Falret by the middle of the nineteenth century.

It is a truism that the relationships between literature and visual entertainment are multiple, complex and variable, especially if we consider literature in the broad sense and keep in mind the enormous variety in the forms of spectacle. Actually, several dangers lie in wait for the one who, on the comparative level, deals with the problem of the relationships between a literary work and a work intended to be viewed as visual entertainment.

The 57Fe Mössbauer spectra of six nontronite samples were measured at appropriate temperatures of 4.2 and 1.3 K. Three of the nontronites gave a complex magnetic hyperfine spectrum showing magnetic ordering at 4.2 K, and the other three required a lower temperature of 1.3 K to produce similar magnetic ordering. The spectra were computer-fitted with three closely overlapping sextets which are considered to arise from: (1) Fe3+ that is ordered magnetically in the cis-octahedral sites with a greater number of neighboring tetrahedral Fe3+ ions (51 T); (2) the cis-octahedral site with the greater number of neighboring Si4+ ions (46 T); and (4) the tetrahedral sites (41 T). In an untreated sample a further sextet corresponding to interlayer Fe3+ (36 T) was identified. The magnetic ordering was complicated and not directly related to the iron content of these sites. It probably depended also on the overall composition and structural order of the particular nontronite. The ordering appears to have been essentially two-dimensional, consistent with the layer structure of this material.

Three main issues are of cardinal interest in this paper. The first issue relates to the canons of discourse—the parameters that inform and guide any discussion—in African philosophy. These canons are accepted in one form or the other by the philosophers who have actually formulated some of them and those who have devoted their academical careers to the promotion of the positive study of African philosophy. Consequently this paper should be viewed in the same light as C.E.M. Joad's A Critique of Logical Positivism in which the “Great Tradition” in philosophy is classically expounded and defended against the onslaught of the philosophical exuberance and extraordinary claims of the logical positivists in the sense that it is a rejoinder to the attack on African philosophy by those who actually may want to be known as African logical neo-positivists.

The weathering of eastern Australian basalts, sampled from the rounded, hard, core-stone to the rind of softer weathered material, has been examined by bulk chemical analyses, thin section petrography, electron microprobe, and X-ray powder diffraction analyses. Using density as a measure of weathering intensity, data from four core-stones show that at a stage of weathering in which the total loss due to dissolution is – (i.e., at the core-stone rim), the percentages lost of the following major elements are: Ca, 85; Mg, 80; Na, 70; K, 50–80; P, 55; Si, 45; Mn, 40; Al, 5; Fe, 0; and Ti, 0. With more intense weathering, deposition of some elements, particularly rare earths and Ba, and mobilization and deposition of Al and Fe make quantification impossible. The rate of weathering of individual minerals is consistent with the well-known susceptibility series: glass ∼ olivine > plagioclase > pyroxene > opaque minerals. Clay minerals in the core-stones are dominated by smectites, whereas those in the surrounding more intensely weathered rinds are dominated by halloysite and goethite.

In alkaline media and at 70°C dilute suspensions of ferrihydrite transformed to goethite between pH 11.2 and 14 and to a mixture of goethite and hematite above and below this pH range. Increasing the temperature of the transformation or the concentration of the suspension reduced the pH range in which goethite alone formed. The morphology of goethite was chiefly a function of the pH of the system. Acicular crystals formed at all pHs and exclusively above pH 12.2. Epitaxial twinned crystals predominated at pHs below 11, and twins free from hematite formed at higher pHs. Increasing the suspension concentration, ionic strength, or temperature extended the pH range over which twinned crystals formed. Electron micrographs showed that twins formed mainly during the initial stage of the transformation, whereas acicular crystals formed over a longer period. Thus, the twins appeared to nucleate in the ferrihydrite; nucleation of acicular particles took place in solution.

The present research documents new distributional records of two gobioid fishes, Acentrogobius vanderloosi Allen, 2015 and Pseudogobius fulvicaudus Huang, Shao, and Chen, 2014 from the southeastern coast of India. Indian coastal waters provide suitable habitats for many gobioid fishes due to its varied ecosystems. The confusion over the identity of a number of gobioid fishes in India suggests the need for more studies on these fishes to better understand their diversity, taxonomy, and geographical distribution. The present record of these species from the southeastern coast of India expands the known distribution of these species.

This paper investigates correlations between theme vowels and argument structure in Serbo-Croatian. Specifically, we focus on two different theme vowels, -i- and -ova-, isolating ‘minimal pairs’, that is cases where the same base combines with the two theme vowels to derive different verbs. Starting from two online corpora of Serbo-Croatian, we created a comprehensive list of -i-/-ova- minimal pairs. For all pairs in the list whose both members were attested at least 50 times in the corpora, we randomly selected 50 tokens per verb and annotated them for transitivity. A statistical comparison of -i- and -ova- verbs according to the proportions of transitive uses was carried out. The findings show that -i- verbs are much more likely to be used transitively than -ova- verbs. This finding corroborates the view that theme vowels are associated with argument structure properties and challenges the idea that they are universally ‘ornamental’ pieces of morphology without syntactic/semantic import. Based on these and supplementary (non-corpus) data, we claim that -i- derives transitives and unaccusatives, while -ova- derives unergatives. We propose a model couched in Distributed Morphology whereby these two theme vowels are treated as instantiations of different ‘flavors of v’.