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Until now, the different attempts to describe the defects of kaolinites were based on the ideas that (i) the hkl reflections with k = 3n are Bragg reflections, while (ii) the hkl reflections with k ≠ 3n are affected by ±b/3 translations or ±2π/3 rotations. With regard to this conception, this work provides several important precisions: (i) The h, 3n, l′ reflections are true continuous diffraction bands, more or less modulated, and disturbed by the existence, in the stacking, of random shifts parallel to the layer plane. (ii) The major defect in natural kaolinites is not the ±b/3 translation, but the displacement from one layer to the other (or from one domain to another in the same layer) of the Al vacancies. (iii) The model containing true rotation of layers should be rejected because it does not allow us to interpret all the different parts of the experimental diagrams. Such a concept of defects in kaolinites is in agreement with the existence of polytypes of kaolinite, with the presence of twins, and allows us to interpret some physico-chemical properties such as the infrared spectra.
Oxidation of octahedral ferrous iron in biotite by saturated bromine water results in a loss of both octahedral and interlayer cations. The hydroxyl adjacent to vacant octahedral cation sites adopt an inclined orientation resulting in a more stable environment for interlayer cations. The only structural change accompanying these processes is a decrease in b-axis dimension which is linearly related to octahedral ferric iron content. These findings are in agreement with observations made on naturally weathered biotites.
Some dehydroxylated sericites were boiled with solutions of various salts. A rectorite-like regular mixed-layer was formed when 2M sericite was treated with solution containing salts such as NaNO3, Na2SO4, CaSO4, CaCl2, MgCl2 and MgSO4 respectively. A random mica/montmorillonite mixed-layer was formed from 1M sericite. In order to change the 2M sericite into a regularly interstratified mineral, they are heated to the temperature range of dehydroxylation. The formation of a regularly interstratified mineral from 2M sericite can be explained by the change in the (OH) bond direction after the extraction of the potassium ion.
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.