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An experiment was conducted on the development of Hypogymnia physodes (L.) Nyl. from soredia to branched lobes near the copper smelter in the Middle Urals 10 years after emission cessation. Soredia were cultivated in fir-spruce forests in heavily polluted and unpolluted areas. In both areas, soredia development was examined on fir bark collected from both the heavily polluted and unpolluted areas. The probability of lobe formation was lower in the polluted area even when soredia were cultivated on bark from the unpolluted area. Bark from the polluted area negatively impacted the success of soredia development, irrespective of the cultivation area. The lowest success of early development occurred when soredia were cultivated on polluted bark in the heavily polluted area, where the already low probability of lobe formation was accompanied by high mortality of the developed lobes. This study underscores the enduring impact of industrial pollution on H. physodes development, highlighting the need for ongoing environmental restoration and monitoring efforts in post-industrial areas to support biodiversity conservation.
A knowledge of the distribution of pore sizes in clay and soil bodies is a useful element in the microstructural characterization of such materials. Pore-size distributions and total porosity of a number of reference clays, naturally-occurring subsoils, and commercial clay samples prepared in various ways were determined by mercury porosimetry. The range of equivalent pore diameter explored covered almost five orders of magnitude, from several hundred microns down to approximately 150 A. The method and its assumptions are critically evaluated, and measurements of the contact angle of mercury on clays yield values of 139° for montmorillonite and 147° for kaolinite and illite clays. The extent of shrinkage on oven-drying prior to mercury intrusion is assessed in each case and found to vary from insignificant to as much as 30 per cent of the pore space, depending on microstructural state and degree of initial saturation. The development of techniques for water removal which do not involve change in pore structure is explored. Some preliminary results for structurally weak saturated clays suggest that critical-region drying and perhaps freeze-drying procedures may be practical.
The effect of swelling on the b-dimension of Na-saturated, Upton, Wyoming montmorillonite was re-examined using powdered silicon as an internal standard. After being corrected with reference to the internal standard, the b-dimension did not increase through the entire range of swelling as reported previously. It increased up to a water content of ~3.0g/g montmorillonite and remained constant thereafter. However, the diffraction peak of the internal standard shifted towards lower angles at higher water contents. This shift was attributed to a relaxation of the wetter samples away from the knife edge of the diffractometer. Presumably, a similar relaxation occurred in the earlier study and was responsible for the apparent increase in b-dimension at water contents above ~3.0g/g.
The b-dimension of Upton montmorillonite saturated with different cations was determined using powdered silicon and a colloidal quartz impurity as internal standards. The water content at maximal swelling decreased as the b-dimension increased.
Two mutually exclusive views exist concerning the relative stabilities of gibbsite and boehmite in soils. These are examined in terms of experimental and thermodynamic evidence and it is shown that all three possible divariant assemblages of two phases that can exist between gibbsite, beohmite and H2O, may do so at 25°C and 1 atmosphere total pressure depending on the status of H2O. It is further shown that the conditions of H2O chemical potential needed to stabilize boehmite + H2O relative to gibbsite + H2O or gibbsite + boehmite, are unlikely to occur in natural waters in the zone of weathering.
The equilibrium diagrams developed for Al-hydroxide and for kaolinite by Garrels and Christ (1965) have been modified by taking into account the existence of gels. From the stability zones obtained, the “appropriate” concentrations can be deduced and utilized for synthesizing these species, provided the requirements to insure good crystal growth are observed. Among procedures to promote these crystallizations, homogeneous precipitation processes (La Iglesia et al., 1974, 1976) appear to be particularly adequate.
The theoretical considerations provide an explanation for most of the processes observed until now, both successful and unsuccessful syntheses, and also give an explanation for many field observations. The crystallizations, however, remain poorly reproducible, indicating that many factors are still poorly known. Some points requiring further investigation include (i) better values for ΔGr0, (ii) the influence of organic complexes, (iii) the effect of preexisting crystalline phases, (iv) those involving dehydration processes in these systems.
Crystallographic properties of illite and chemical properties of organic matter in various mudstones ranging in age from Archean to Miocene were investigated. The breadth of the (001) X-ray powder diffraction peak of illite correlates significantly with the ratio of aliphatic to condensed-aromatic components and the degree of condensation of aromatic rings of the polar (“humic”) fraction of extract-able bituminous organic matter. The broader the diffraction peak, the less highly condensed and aromatic (i.e. less highly humified) is the organic matter associated with the illite. Breadth of illite diffraction peak and degree of humification of polar organic matter vary in a complex and apparently systematic way through geologic time. All of the three different suites of mudstones investigated (“calcareous,” “non-calcareous,” and “glacial” mudstones) gave similar patterns of secular variation. In addition, the ratio of diffraction intensities for the (002) and (001) reflections (I002/I001) of illite in calcareous mudstones and limestones showed a strong negative correlation with geologic age, indicating that the illites in the older rocks are enriched in magnesium with respect to aluminum.
The correlation between crystal structure of illite and degree of humification of its associated organic matter could, by itself, be interpreted as an effect of post-depositional maturation processes, whereby “crystallinity” and degree of humification both increased as functions of heat and pressure. However, the patterns of secular variation suggest that the observed variations are primary, or were pre-determined by primary characteristics of the sample materials. The possibility that the original structure and composition of the organic matter influenced post-depositional changes in the crystallographic properties of sedimentary clay minerals, or post-depositional genesis of clay, would seem to merit consideration. The demonstrated relationship between crystallographic properties of illite and the nature of the “humic” matter constitutes evidence that most of the extractable organic matter is truly indigenous to the rock in which it occurs. The results also imply that molecular structure of extractable organic matter can be used in place of the breadth of the (001) diffraction peak of illite as an index of incipient metamorphism within a single formation or stratigraphic sequence, provided the primary characteristics of the organic matter are nearly the same in all samples. This method would have the advantage of being applicable to all sediments, not just those containing illite (specifically, aluminum-rich illite).
The secular variation of the I002/I001 ratio of illite in calcareous sediments is provisionally ascribed to diagenetic processes whereby magnesium is abstracted from pore water and groundwater and is gradually assimilated into the crystal structure.
The microelectrophoretic and adsorption behaviour of lithium vermiculite has been studied as a function of lithium chloride concentration. This was done in an attempt to establish the applicability of such systems to the testing of theories of interaction of flat plates, and in so doing to throw further light on swelling measurements performed on such materials. The studied behaviour, while highly unusual, gave quite good agreement between adsorption and microelectrophoretic parameters and agreed, qualitatively, with some earlier measurements on similar materials.
The observed properties appear to be due to some rather specific structuring effects, either of the oxide surface or of the electrolyte ions. If this is so, these systems are far from ideal models for the testing of the theory of interaction of two uniform flat plates.
The interaction of water with synthetically prepared goethite (α-FeOOH) and amorphous hyd-rated ferric oxide surfaces was studied using i.r. absorption and water vapor adsorption measurements. I.R. results show that the last traces of physically adsorbed water are removed from the amorphous material by outgassing at 25°C. In contrast, goethite retains approximately a monolayer of physically adsorbed water with similar outgassing. This monolayer of water on goethite, which is presumably hydrogen-bonded at least in part with structural hydroxyls, is readily exchangeable with D2O.
Integral entropies of adsorption were evaluated from water vapor adsorption isotherms at 15, 25 and 35°C and compared with values for mobile and immobile layers calculated through application of statistical mechanics (McCafferty and Zettlemoyer, 1970). Entropy values for both the first physically adsorbed monolayer of water on the amorphous material and the second monolayer on goethite were about the same as or greater than those calculated for an immobile layer, indicating strong hydrogen bonding of water by both surfaces. The larger deviation between the entropy values for goethite and those calculated for the immobile layer may be associated with changes in the structure of the first as well as the second physically adsorbed water layers. Surface areas, calculated using the BET method, were 320 and 32 m2 g-1 for the amorphous material and goethite respectively. Since the unit surface activity is probably about the same for the two materials, it follows that as the amorphous material crystallizes to form goethite, there would be a reduction in total surface activity in proportion to the reduction in surface area.
Potassium was removed from 5 to 20-μ size fractions of two phlogopites by treatment with sodium tetraphenylboron and replaced with various exchange ions. The b-dimension of the mica increased with K+ removal, which suggests that the K+ ion in phlogopite acts to constrain b. This being the case, the K—O bond in phlogopite must be lengthened and weakened relative to the K—O bond in dioctahedral micas.
The crystal structure of natural boehmite, AlOOH, from Tveidalen, Langesundsfjorden, Norway, with a = 3.693(1), b = 12.221(2) and c = 2.865(1) Å, was refined from single crystal X-ray diffraction data (MoKα maximum 2θ = 120°) to an Rw value of 0.032 in space groups Amam and A21am. In both cases the proton was found to occupy positions of the type (x, 0.038, 0), where x = 0.104 and 0.396, about 0.75 Å from the donor oxygen atom. This arrangement corresponds to the presence of chains of asymmetric hydrogen bonds with random polarity parallel to the a axis, and indicates that the effective space group is Amam. No significant electron density was observed either at the center (0, 0, 0) or at the position (1/4, y, 0), corresponding to symmetric and bifurcated hydrogen bonds, respectively, between the layers of octahedra.
Calculations of the total energy of a representative portion of the boehmite structure as a function of hydroxyl orientation, using semiempirical molecular orbitals of the Hückel type, are in agreement with the observed electron density distribution and suggest a preference for (1) sp3, rather than sp2, hybridization of the donor oxygen atom orbitals, and (2) asymmetric, rather than symmetric hydrogen bonds. Disorder of the hydrogen atom positions within individual hydrogen bond chains is shown to be much less likely than disorder between adjacent fully coherent chains.
In the subsection “Grammar of Eros (The Language of Love)” in section 2 of book 2 of The Star of Redemption, the beating heart of the work, Franz Rosenzweig offers a peculiar portrait of the event of revelation. What is presented is a dramatization of the encounter between the loving God and the beloved human soul, a developing scene consisting of a series of utterances and experiences, many of which appear unwarranted. Why does Rosenzweig present revelation in this manner? This article seeks to explain the seemingly arbitrary twists and turns in the dramatized “plot” through which Rosenzweig depicts revelation by demonstrating that it follows in its main features the prevalent Protestant understanding of revelation as encompassing not only divine self-disclosure but also the discovery of sin, confession, forgiveness of sin, reconciliation, attainment of selfhood, and redemption, and is framed according to the directives of the Lutheran foundational principle of “at once a sinner and justified (Simul Justus et Peccator). In so doing, it exhibits Rosenzweig’s deep embeddedness in the Protestant theological discourse of his time and shows that The Star should be understood in light of the contemporary Protestant theology.
The crystal structure of a synthetic boehmite sample has been refined to an R of 0.047 in the space group Amam from X-ray powder diffraction data. Inclusion of hydrogen atoms and/or refinement in the space group A21am gave poorer results. Cell dimensions were determined as a = 3.6936 (± 0.0003), b = 12.214 (± 0.001), c = 2.8679 (± 0.0003) Å. All Al-O(OH) distances lie between 1.88 and 1.91 Å. Shared octahedral edges are 2.51–2.52 Å, and unshared octahedral edges are 2.86–2.87 Å, in excellent agreement with those for layered silicates. The O-H … O distance between contiguous octahedral sheets is 2.71 Å. The computed X-ray pattern matches closely with the experimental pattern, indicating the degree to which the crystal structure has been determined.
Clay mineral compositions in specimens of Recent marine sediments in the neighbourhood of Japan and sedimentary rocks from Japan were studied. Identification of the clay minerals was made chiefly by X-ray, differential thermal and infrared analyses. Their relative amounts were determined by comparing the intensities of their basal X-ray reflections.
Recent marine sediments: Specimens from the bottom of the Northwestern Pacific Ocean contain montmorillonite, illite, chlorite and kaolinite. The amount of mont-morillonite varies locally, but that of kaolinite is generally small. Clay mineral compositions of the Eastern Sea specimens are different from those of the Northwestern Pacific Ocean and the crystallinity of clay minerals seems to be better in the Kastern Sea. It is most likely that the clay minerals in the Eastern Sea sediments were supplied from the continent. Specimens of the bottom sediments at the entrance of Tokyo Bay contain montmorillonite, illite, chlorite and a lesser amount of kaolinite. The amount of montmorillonite varies markedly with locality and tends to be low where the movement of sea water is relatively intense. This may be due to a finer particle size of montmorillonite in comparison with the other clay minerals.
Sedimentary rocks: The relationship between sedimentary formations and clay mineral compositions shows that the compositions are characteristic of the depositional environments. For example, kaolinite is abundant in the formations deposited in fresh water but its content is low in the formations deposited under marine environment. The Paleozoic formations from the Tohoku region contain chlorite and illite without exception; however, the Mesozoic formations contain them in various proportions according to localities.
Interlayer K in muscovite, biotite, phlogopite, illite and vermiculite-hydrobiotite samples was replaced by cation exchange with Na. The rate and amount of exchange varied with the mineral and the level of K in solution.
Essentially, all the K in muscovite, biotite, phlogopite and vermiculite was exchangeable when the mass-action effect of the replaced KT was reduced by maintaining a very low level of K in solution. The time required for this exchange varied from < 10 hr with vermiculite to > 45 weeks with muscovite. Only 66% of the K in the illite was exchangeable under these conditions. When the replaced K was allowed to accumulate in the solution, the amount of exchange was determined by the level of K in solution required for equilibrium. These levels decreased with the degree of K-depletion and with the selectivity of the mica for K. The order of selectivity was muscovite > illite > biotite > phlogopite > vermiculite. Decreasing the K in solution from 10 to 7 ppm increased the exchangeable K in biotite from 30 to 100%. A K level of only 0.1 ppm restricted the exchange of K in muscovite to 17%.
A decrease in layer charge was not required for K exchange, but a decrease did occur in K-depleted biotite and vermiculite. Muscovite with the highest layer charge (247 meq/100 g), least expansion with Na (12.3Å), and least sensitivity to solution pH had the highest selectivity for K and the slowest rate of exchange. The K in vermiculite was the most readily exchangeable.
Conductometric titrations of clay suspensions with surfactant solutions offer a rapid method of surface area determination of clay particles suspended in aqueous media. A cationic surfactant, dodecylamine hydrochloride, was used in this investigation. This surfactant was adsorbed by electrostatic bonding at cation exchange sites and by van der Waals forces. A monomolecular or bimolecular layer of the surfactant coats the particle and the completion of the layer is determined from a change in slope of the conductometric titration curve due to the formation of micelles. Good agreement between this method and BET determined values were obtained for kaolinite. The bentonite suspensions had a strong tendency to flocculate after the initial stage of adsorption causing the results to vary considerably. This method of surface area measurement of clay particles offers many advantages over the present techniques: (1) a dry particle is not required; (2) the equipment is inexpensive and available in many laboratories; (3) the method is rapid; (4) vacuum and high temperature are not required, and (5) the method measures the internal as well as external surface area.