To examine the effects of clay swelling and dispersion on electrolyte concentration-permeability relationships of low clay content soils, flow experiments were conducted on a silt of fixed particle size distribution containing 0, 5, 7·5, 10 and 15 per cent clay (sodium illite, 2 μm fraction). Flocculated specimens were sedimented using both slow and rapid procedures. After compression each specimen was permeated successively with electrolyte solutions which caused (1) swelling of the clay fraction (0·10 N), and (2) dispersion (0·05 N). Absolute permeabilities varied with clay content, sedimentation procedure, compression rate, and electrolyte concentration; however, the form of this variation plotted against through-put volume was similar for all specimens containing electrolyte solutions causing only swelling of the clay. Increasing the hydraulic gradient above a critical value apparently increased the swelling slightly as evidenced by further reductions in permeability. The permeability of mixtures permeated with electrolyte solution causing dispersion of the clay was more complex and depended on clay content, the hydraulic gradients used to introduce the dispersing electrolyte solution and the pre-dispersion gradients to which the specimens had been subjected. Permeability decreases were attributed to the last stages of swelling prior to dispersion and to pore plugging. Increases in permeability were the result of erosion of dispersed particles. Specimens previously subjected to the highest gradients while swelling dispersed more rapidly and had a greater tendency to erode. The effects of predispersion gradients diminished with increasing clay contents. It is concluded that both compositional and mechanical factors play an important role in determining electrolyte concentration-permeability relationships for soils containing active clay minerals.

Sericite was K-depleted with molten LiNO3. The sample was changed into an interstratified structure in the presence of a small amount of LiNO3 after prolonged treatment, and in the presence of a considerable amount of LiNO3 a similar structure was formed after about 3 hr of reaction. In the case of the presence of the proper amount of NaCl, a mixed-layer structure was easily obtained by treatment for a long period of time with a considerable amount of molten LiNO3.

The interstratified mineral had a basal spacing of 22 Å–23·3 Å which was expanded to 25 Å–27·6 Å by treatment with ethylene glycol.

Nitrogen surface areas and pore-size distribution curves of various chrysotiles have been measured using a continuous flow method. A model founded on a hexagonal close packing of fibers has been adjusted to fit the frequency distribution curve of the fiber outside diameters obtained from electron micrographs. From this model, theoretical distribution functions of the surface area versus the pore diameter were computed and compared to the experimental data. For one fiber only (i.e. Coalinga chrysotile), the good agreement between the computed and experimental data allows one to conclude that the external pores (between the fibers) and the internal pores (within the fibers) are free from any amorphous material. For the other studied chrysotiles, the degree of filling of the pore system by amorphous materials was always higher than 50%. Under these conditions, hydration water cannot be removed unless the samples are pretreated in the 300°–400°C temperature range. On the contrary, water is driven off from the “clean” Coalinga fibers at temperatures lower than 100°C. Surface area measurements derived from water-adsorption isotherms correspond to those obtained with nitrogen after the hydration water has been removed.

Equivalent conductivities of adsorbed cations were determined in clays saturated with Na+, Cs+, Ca++ and with mixtures of these cations. Measurements were also made on Ca++ clays which had been forced by previous drying into bundles of platelets or tac-toids. The average mobility of adsorbed Ca++ and Cs+ is much lower than that of adsorbed Na+.

It was concluded that the average mobility of adsorbed Ca++ is low because most of this Ca++ is on the internal surfaces of tactoids. Ca++ adsorbed between these internal surfaces appears to have a mobility much lower than Ca++ on the external surfaces which has a mobility of the same order of magnitude as Na+. Polarization of adsorbed Cs+ accounts at least partially for its low mobility in these clays.

Demixing of adsorbed cations (segregation with Na+ dominant between some platelets and Ca++ between others) is suggested as an initial step leading to breakup of a Na+-Ca++ clay mass into tactoids. The tactoid model, with Ca++ and Na+ preferentially on the internal and external surfaces respectively, furnishes an explanation of the instability of clay and soil aggregates with 15% exchangeable sodium.

Adsorption studies have been performed on Georgia kaolins having a broad range of crystallinity and particle size distributions (from 0·1μ to 44μ) using N2 (78°K.), H2O (273°K.), and BuNH2 (298°K.). Using both vapor and liquid phase adsorption techniques, surface affinities of the adsorbates were determined.

Modified Frenkel-Halsey-Hill plots were used to compute the preferential adsorptivity of H2O vapor over N2 (hydrophilicity index, H.I.) as a function of crystallinity index, C.I., and particle size. For amine adsorptivity, non-aqueous adsorption isotherms were obtained.

Within any geographic deposit, crystallinity exhibits an inconsistent pattern with respect to particle size. A single generality is the tendency for crystallinity to increase toward the fine particle size range, D → 0·2μ. Adsorptivities of N2, H2O, and BuNH2 show no dependence upon crystallinity within a given particle size range. However, F.H.H. compensated slopes, describing the preferential adsorptivity over N2, show a definite decrease as crystallinity increases. A striking anomaly occurs in the vicinity of 0·2 > C.I. > 0·7 where H.I. increases briefly then returns to the original trend. The rate of decrease of H.I. vs. C.I. is consistently steeper with increasing particle size. Adsorption of water vapor most likely occurs as a 1:1 configuration on each silica-alumina edge group, 1:1 on each basal silica, and 1:2 (hindered configuration) on each basal alumina group.

The data suggest that amines adsorb preferentially and quantitatively on the edges, i.e. the Lewis and Bronsted acid sites, and follow a Langmuir pattern.

The implication by Murthy and Ferrell (1972) that interstitial water studies are in a confused state is criticized on the basis that the authors have not drawn on a considerable body of data, especially Soviet studies since the 1950’s, and results of the Deep Sea Drilling Project. Pressure filtration systems for extracting interstitial waters are currently the methods of choice for marine studies and have achieved substantial reliability and reproducibility. Although gaps and problems remain, many aspects of interstitial composition of marine sediments have been clarified; these include the substantial constancy of composition of interstitial waters in deep sea pelagic deposits, depletion of interstitial cations owing to authigenic mineral formation in more rapidly accumulated (especially terrigenous) sediments, and special phenomena in sediments overlying salt deposits.

The basic salts of this system were prepared and their structures and physico-chemical properties were studies by electron microscopy, chemical analysis, X-ray powder diffraction, thermal analysis, i.r. absorption spectra, BET absorption, and acidity-basicity measurements. The salts were found to be new compounds analogous to hydrotalcite. They can be expressed by the formula; where M2+ and M3+ denote di- and trivalent cations, A− and A2− denote mono- and divalent anions, respectively, and y = z1 + 2z2; z1 ≫ z2.

The structures consist of positively charged Cd(OH)2-like basic layers and intermediate layers formed from anions and water molecules with the solid solution of divalent cation (M2+) and trivalent cation (M3+) being formed in the range of 0.6 < x/(x + y) < 0.9. The anions of Cl−, NO3− and ClO4− are easily substituted by CO32−. A large part of the NO3− makes a monodentate-type bond and the ClO4− a bridge-type bond.

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.