The hydrophilic-hydrophobic properties of four thermally decomposed organoclays, the octadecylammonium-, the dimethylaryloctadecylammonium-, and the dimethyldioctadecylammonium-bentonites and the dimethyldioctadecylammonium-hectorite, were examined through adsorption isotherms with nitrogen, water vapor, and hexane. Along with DTA and TGA results, these clay complexes appear to undergo transitions from low to higher degrees of hydrophilicity as more and more of the hydrocarbon chains are dehydrogenated at successive temperatures up to 400°C.

Clay (<2 μm) and fine silt (2–20 μm) fractions of twenty seven soil samples from eight tropical ferruginous profiles of the Mysore Plateau (India) were analysed for kaolinite by dehydroxylation and selective dissolution. The considerable amounts of iron extracted by the procedure and the closeness of the SiO2/R2O3 molar ratios (2·00–2·18) to the ideal value of 2·00 indicated that iron was a structural constituent of the kaolinites. The calculated unit cell cation composition of the kaolinites showed a substitution of 0·11–0·82 atoms of Fe(III) for Al in every four octahedral sites. The kaolinites in these soils appear to be products of crystallization from weathering solutions.

Interlayer potassium was removed from a wide range of mice minerals by treatment with dilute solutions of n-dodecylammonium chloride. On subsequent reaction with the appropriate metal methoxide, the Na+ or Ca2+ form of the altered mica was produced. The properties of the original and sodium saturated samples were compared to assess the changes in water content, charge density and chemical composition (particularly ferrous iron) which resulted from the displacement of potassium.

Calculation of structural formulae was not attempted since it was established that for the altered samples accurate distinction could not be made between adsorbed and structural water. Changes in layer charge are thus expressed on the basis of samples ignited to 1000°C. Charge losses of up to 76 me/100 g were recorded for biotites, smaller charges were noted for phlogopites and no loss was observed for the two muscovites examined.

Oxidation of ferrous iron occurred for all trioctahedral samples, the greatest oxidation occurring in the samples initially high in iron. There was no consistent relationship between the amount of iron oxidized and the loss of layer charge.

All altered samples contained greater amounts of H2O+ than the original materials suggesting that protonation of structural oxygens occurred during, or following, removal of potassium.

It is concluded that the alteration of micas by reaction with organic cations is a complex process, differing in detail for different micas, and following a similar path to alteration by reaction with inorganic salts.

The Si/Al ratio of an hydrothermal system plays an important role in kaolinite synthesis. If the atomic Si/Al ratio of a system is greater than 2-0, kaolinite will disappear at 345 + 5°C and 2 kbars water pressure according to the reaction kaolinite + 2 quartz → pyrophyllite + H2O. If the atomic Si/Al ratio is less than 2-0, however, kaolinite will persist until 405°C where it will react according to the equation 2 kaolinite → pyrophyllite + 2 boehmite + 2 H2O. The Si/Al ratio of the system and temperature are also factors in determining whether b-axis ordered or disordered kaolinite will crystallize. The ordered variety is favored by a lower Si/Al ratio and a higher temperature than is the disordered form.

Hydrothermal experiments also show that kaolinite can be synthesized at 150°C and 5 bars pressure in distilled water from amorphous starting materials. Previous investigators were unsuccessful in forming kaolinite under these conditions because their systems were contaminated with alkalis.

Attempts to synthesize halloysite and dickite failed, but halloysite was converted to kaolinite at 150°C, suggesting that halloysite can be synthesized only at low temperatures.

In the past decade, the practice of investor–State arbitral tribunals addressing investment protection in the context of armed conflict and military occupation has expanded. This has prompted a growing interest in the relationship between international investment law and international humanitarian law (IHL), two regimes with markedly different relationships to war—IHL more pragmatic and international investment law more idealistic. This article argues that, while its lack of pragmatism might render international investment law ineffective in changing how war is conducted, it is the regime under which States are most likely to be held liable for the conduct of war. This is a result of its more robust primary obligations, more effective enforcement mechanisms and large awards of damages. Nevertheless, comparing international investment law and IHL does also reveal some similarities—the legacy, it is argued, of a time when the laws of war were more about protecting private property and neutral commerce than civilians. Putting these two regimes together in this way exposes international law's uneven distribution of protection in war.

Crystallites of the finest fraction of a clay mineral from Rosamund, California, which account for over 50 per cent of the total weight, are identified as wairakite single crystals of 0·1–1 μ size. High-magnification electron microscopy revealed flat, almost perfectly square-shaped lamellae, which consist of superimposed layers of approximately < 50 Å thickness. Electron diffraction patterns from a selected single crystal proved that the basal plane of the crystallite aligned perpendicular to the electron beam is the (111) plane. It is suggested on the basis of the present study and the report of previous investigators that the pseudocubic wairakite crystals cleave along their (111) and ($\bar 1$11) planes. The indices of high order reflections, unpublished or previously reported as uncertain, are determined.

A structure model for amorphous hydrated or dehydrated silico-aluminas with composition varying between 0 < Al: Al + Si < 1 is presented. A central core made from a tetrahedral network in which silicon is partially substituted by aluminium carries a net negative electrical charge. This charge is balanced by more or less polymerized hydroxyaluminium cations forming a coating around the core.

As Al: Al + Si increases, the number of substitutions in the core increases as well as the complexity of the hydroxyaluminium cations in the coating.

For Al: Al + Si ≳ 0·8, a demixing is observed, leading to the formation of a crystalline pseudo-boehmite and bayerite.

Upon heating, the coating as well as the demixed phases are transformed into a spinel structure containing tetrahedral aluminium, while the core structure remains unaffected.

This model could explain the solubility features, the phosphate reaction and the catalytic properties of amorphous silico-aluminas.

The crystalline and osmotic swelling of Na-, Cs-, Mg- and Ca-montmorillonite has been measured in dimethyl sulphoxide and in formamide, N-methyl formamide, dimethyl formamide, N-methyl acetamide and dimethyl acetamide. These liquids have similar dipole moments but their relative permittivities vary appreciably from values less than water to values greater than water.

Na-montmorillonite exhibits osmotic swelling (diffuse double layer development −d(001) ≫ 19 Å) in formamide and N-methyl formamide and Cs gives osmotic swelling behavior in formamide. Cs-montmorillonite in the crystalline swelling region give spacings greater than those found for water with all liquids. Mg- and Ca-montmorillonite did not give spacings greater than 19 Å in any of the liquids studied.

The swelling behavior of montmorillonite is affected by relative permittivity but for liquids with a similar relative permittivity methyl substitution in the molecule may prevent the development of diffuse double layers on the particle surfaces.

The small angle X-ray scattering data obtained in an earlier investigation of a series of Na-montmorillonite clay samples containing varying concentrations of sodium metaphosphate have been used to calculate the potential energy φ(x) of the interaction between two isolated parallel clay platelets separated by a distance x. All φ(x) curves have the form expected for Na-montmorillonite. In each curve there is a potential well for a platelet separation approximately equal to the most probable separation distance determined in the earlier study. Because the depth of the potential well is of the order of 0·01 eV for all samples, the attractive forces are relatively weak. While the calculated φ(x) functions are not highly accurate, in future investigations precautions can be taken to increase the reliability of the computed potential energy functions. This preliminary study suggests that determination of φ(x) from small angle X-ray scattering data can be a useful method for quantitative study of interparticle forces in Na-montmorillonite clays.

For billions of people, the internet has become a second home. It is where we meet friends and strangers, where we organise and learn, debate, deceive, and do business. In some respects, it is like the town square it was once claimed to be, while in others, it provides a strange new mode of interaction whose influence on us we are yet to understand. This collection of papers aims to give a short indication of some of the exciting philosophical work being carried out at the moment that addresses the novel aspects of online communication. The topics range from the expressive functions of emoji to the oppressive powers of search engines.