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Ion exchange analyses of the clay-sized fraction of sediments in Lakes Pontchartrain and Maurepas suggest the selective adsorption of Na at the expense of Mg. The literature suggests that Mg should be preferentially adsorbed. As the chlorinity of the lake waters increases from 300 mg/l to 3250mg/l, the percentage of exchangeable Na increases from 13·6 to 30·6 while the percentage of exchangeable Mg decreases from 65·6–36·8. The observed exchangeable Na percentages are higher than the ones calculated from the sodium-adsorption-ratios. The difference is attributed to an increase in the Na exchange constant of the sediment and therefore an increased selectivity for Na. With an increase in chlorinity, montmorillonite increases from 47 to 61 per cent and the total of the exchangeable cations (Na, Mg, Ca, K) increases from 36 to 82 m-equiv./100 g.
Transmission and diffraction electron micrographs were made of illite and montmorillonite to study the changes that take place as the clays were heated continuously to 1200°C.
In both of the clay minerals studied, expulsion of a highly fluid material occurred subsequent to dehydroxylation and prior to the development of the first-formed high temperature phases. It was hypothesized that this material represented the expulsion of constituents in the clay in excess of those needed for the formation of the first high-temperature phase. Electron diffraction indicates that the high-temperature phases that formed all developed with some preferential orientation, and were strongly influenced in their development by the structure of the original clay.
The new species Caloplaca tswaluensis is described from Tswalu Kalahari Reserve, Northern Cape Province, South Africa. Caloplaca tswaluensis occurs on the trunks of Vachellia erioloba (camelthorn) trees and is characterized by its 3-septate to quadrilocular ascospores. Molecular data indicate that the new species is placed in the subfamily Teloschistoideae but cannot be assigned to any existing genus and, because its systematic position is unclear, we choose to describe it in Caloplaca s. lat. Caloplaca tswaluensis is compared with other crustose Teloschistaceae species with plurilocular ascospores.
The Affordable Care Act’s preventive services mandate requires private insurance plans to serve public health goals. But the employers that facilitate access to insurance for more than half the population hold political views and economic interests that may run counter to public interests. And now, in the name of for-profit employers’ religious rights, the courts are eroding the legal foundations of privately financed public health. Religious objections to the preventive services mandate — of which Braidwood Management, Inc. v. Becerra is just the most recent high-profile example — have become a site of opposition to public health. Courts have radically revised standards for religious exemption, adopting an individualistic frame that discounts population-level effects. Recent decisions could invite free exercise claims that go to the heart of securing population health through the workplace.
The method of known additions for estimating clay-mineral content was reversed in that increasing proportions of soil clay were added to a standard composed of equal weights of kaolinite, illite, and montmorillonite. After glycolation, peak-area ratios were calculated from 7.2 (kaolinite), 10 (illite), 14 and 17 Å (vermiculite and montmorillonite) diffraction peaks of standard, mixes, and soil clay. Ratios were plotted against % soil clay from the standard (0%) through the mixes (14 to 77%). Curves of fit were calculated and projected to 100% soil clay giving theoretical values which agree with measured values. As weight proportions are known in the standard, the projections permit estimates of clay-mineral weight proportions in the soil clay.
The GATT security exceptions were practically in hibernation until recently. The recent WTO disputes panel activity concerning such exceptions is characterized by a standard of review that places the accent on ‘when’ action should be taken and not so much on ‘what’ action should be taken. We see two problems with this construction. First, the ‘when’ might be a function of privileged information that those possessing it might be unwilling to divulge in a transparent manner. Second, national security is an amorphous concept, and unless we disaggregate it, it is impossible to pronounce the appropriateness of measures adopted to pursue the underlying objective. In turn, the absence of disaggregation could lead to false positives and negatives, as the same action could be pursuing essential security or providing protection to domestic players.
This article tells the story of 36 Chinese peasants and their audacious campaign to defend their private rights on two tiny islands in Manchuria from the Japanese empire and a Chinese warlord regime. A borderland in Northeast Asia, Manchuria was a site of intense inter-imperial rivalry in the first half of the twentieth century. Using newly discovered local Chinese archival documents as well as sources produced by Japanese, Korean, and American actors, I discuss how the peasants leveraged their knowledge of multiple property regimes in the borderland to delay and deflect the demands of two states. This microhistory of a transnational dispute illustrates the workings of a form of convergent legal pluralism in the Northeast Asian borderland. While historians agree that state capacity grew substantially in the East Asian borderlands in the early twentieth century, the case shows how that growth also complicated the nature of the state and created new possibilities of bottom-up socio-legal action. It exemplifies the kind of legal cosmopolitanism grassroots actors practised in a world of justice dominated by not-so-cosmopolitan nation-states.
H-ion was added to Na or Ca bentonite suspensions. The H-ion was added either in solution, as HCl, or adsorbed on a cation exchange resin. The variation with time of the quantities of H and Al in various phases of the system was determined.
In the first stage of the reaction both exchangeable H and exchangeable Al on the clay increased rapidly. Several facts showed that the exchangeable Al was not liberated by crystal structure decomposition. It is postulated that its appearance is the result of a rapid dehydroxylation, of hydroxy Al groups located at plate edges or adsorbed on basal planes, producing water and trivalent Al ions.
During the second stage of the reaction, spontaneous self-decomposition of the clay structure takes place. It was found that when the H-clay in alone in suspension or with low concentration of acid, the decomposition stops after the liberation of a limited quantity of Al. Most of this Al is adsorbed on the clay and it becomes the prevailing exchangeable ion. On the contrary, when the H-clay is aging in the presence of H-resin, a system of consecutive reactions is operating. In this system, Al liberated from the structure is transferred to the adsorbed state in the clay and from there to the resin. As a result the decomposition reaction does not stop as in the absence of the resin, but is carried further.
Gradual change from 60% montmorillonite/40% illite randomly interstratified clay minerals at 3500 ft depth to 20% montmorillonite/80% illite at 10,200 ft can be observed in a complete section of Mesozoic shales at Barikewa in New Guinia. The top of a similar complete type Mesozoic section at 10,544 ft in the nearby Omati borehole contains 20–40% montmorillonite in randomly interstratified montmorillonite/illite. From 10,800 ft downward there is only 10–20% expandable material. Consequently depth of burial rather than stratigraphic level controls the proportion of expandable material present. Similar diagenetic alterations occur in the Wilcox Formation, Louisiana, also controlled by burial.
The amount of illite 2M polymorphs in the Papuan samples is usually less than 5 per cent, the illite 10Å peak sharpness ratio is about 1·4. Corresponding values for the Louisiana samples are 43% 2M polymorphs and about 2∙0 sharpness ratio. Chemical analysis of the Papuan shales show low MgO and K2O values when compared with the Louisiana samples. The latter sediments contain some chlorite, the former hardly any. Differences demonstrate a higher proportion of relatively unweathered material in the American samples.
Increase of chlorite content, increase of magnesium content and decrease of kaolinite content from 12,368 ft down in the Louisiana samples suggests a change in sedimentation pattern.
This article explores Naderid Iran's nature of statehood, position in international balance of power, and evolving diplomatic practice. It argues that from 1723 to 1747, the sovereign establishment in Iran remained fundamentally dynastic without giving way to territoriality, continued to acknowledge Ottoman superiority in hierarchy as well as power relations as a principle, and gradually began to adopt, for the first time, early modern specialized phenomena in diplomatic conduct. The study bases itself on the documentation produced by Iranian-Ottoman diplomacy from the Afghan overthrow in 1722 until the aftermath of Nāder Shah's murder in 1747, contextualizes these records in comparison to those of earlier centuries, and treats the Hotaki regime, the Safavid rump state, and Nāder's monarchy in Iran as a whole.
Interstratified layer structures were studied by electron microscopy and electron diffraction. In order to distinguish between expansible and non-expansible layers, Interstratified mica-smectite was treated with laurylamine hydrochloride solution. Electron micrographs of the layers at the curled edges of the crystals show expanded basal spacings of 24 Å and unexpanded spacings of 10 Å. It was observed that adjacent pairs of expanded and unexpanded layers in the micrographs form non-expansible units. Arrangement of the expanded and unexpanded layers shows that the layers expanded by sorption of laurylammonium ions have expansible and non-expansible surface characteristics on opposite sides of the layer. The relationships between the ratio of component layers and basal spacings in two component systems are discussed.
Samples containing allophane with molar Al/Si ratios from 1.0 to 2.0 have been examined by infrared spectroscopy, X-ray fluorescence, and phosphate adsorption methods. The infrared spectra of allophane with Al/Si ratios close to 2.0 showed that the wall of the allophane spherules is made up of imogolite structural units similar to “proto-imogolite.” X-ray fluorescence gave no clear evidence of Al in tetrahedral sites (AlIV), while pyridine adsorption results suggested that a small number of Bronsted acid sites (AlIVOH) are present in silica-rich allophanes. Lewis acid sites (AlH2O) are present in both silica-rich and alumina-rich allophanes. The results suggest that the framework for the allophane structure is an Al octahedral sheet.
Allophanes with Al/Si ratios close to 1.0 contain condensed silicate units either on the outside surface of the Al octahedral sheet, giving rise to a halloysite-like structure, or bonded on the inside surface of an imogolite-like structure. Allophanes with Al/Si ratios between 1.0 and 2.0 appear to be mixtures of the “proto-imogolite” structure and the allophane (Al/Si = 1.0) structure.
A detailed study of sediments from the Triassic of the French Jura shows that clay minerals vary continuously with the facies. Near the coasts of the Jura Sea, sediments consisted of sandy, continental detritus and the minerals are poorly crystallized. At the center of the basin, in what was a cation-rich chemical environment, they are well crystallized. A progressive mineralogical variation can be observed from degraded illite to well-crystallized chlorites passing through the intermediate stages of more-or-less regular mixed-layer structures. This variation is due to a true crystalline transformation.
Similarly, chemical variations in clay minerals and whole-rock samples are related to the paleogeography of the basin. The distribution of major and trace elements is a function of distance from the Jura Sea coastline and also a function of the mineralogical composition of the fine fraction. The most obvious relationships are: (1) An increase in the concentration of MgO and the percentage of ignition-loss water from the coast toward the deep sea; (2) A decrease in the concentration of SiO2, Al2O3, and TiO2 as well as that of trace elements such as vanadium, gallium, and cobalt from the coastal regions to the center of the basin; (3) A lack of statistically significant variations in the concentration of Fe2O3, Mn3O4, B, and Ni throughout the basin.
The authors conclude that: ( 1 ) Transformations (aggradations) observed by means of X-ray diffraction methods are in agreement with the chemical analyses; (2) Transformations are contemporaneous with the sedimentation; they are not diagenetic; (3) Clay minerals play an important role in the geochemical balance of sedimentary basins.
Previous investigations have demonstrated the influences of interlayer cation composition, relative humidity, temperature, and magnitude of interlayer surface charge on the interlayer hydration of montmorillonites and vermiculites. It has been suggested that the sites of layer charge deficiencies may also have an influence upon the amount of hydration that can take place in the interlayers of expandable clay minerals, if the interlayer cation-to-layer bonds are considered as ideally electrostatic, the magnitude of the forces resisting expansion may be expressed as a form of Coulomb’s law. If this effect is significant, expandable structures in which the charge-deficiency sites are predominantly in the tetrahedral sheet should have less pronounced swelling properties than should structures possessing charge deficiencies located primarily in the octahedral sheet.
Three samples that differed in location of layer charge sites were selected for study. An important selection criterion was a non-correlation between tetrahedral charge sites and high surface-charge density, and between octahedral charge sites and low surface-charge density.
The effects of differences in interlayer cation composition were eliminated by saturating portions of each sample with the same cations. Equilibrium (001) d values at controlled constant humidities were used as a measure of the relative degree of interlayer hydration.
Although no corrélation could be made between the degree of interlayer hydration and total surface-charge density, the investigation does not eliminate total surface-charge density as being significant to the swelling properties of three-sheet clay-mineral structures. The results do indicate a correlation between more intense expandability and predominance of charge deficiencies in the octahedral sheet. Conversely, less intense swelling behavior is associated with predominantly tetrahedral charge deficiencies.