The isothermal solid state reactions of Na2CO3 and other salts at 550°C with montmorillonite and with 1:1 mixtures of montmorillonite-illite and montmorillonite-chlorite were investigated. At a concentration of 20 wt. %, Na2CO3 caused the complete destruction of the X-ray powder diffraction (XRD) pattern of montmorillonite alone and in mixtures with other clays. Less deterioration of the XRD pattern was found for NaOH, NaF, K2CO3, and Li2CO3. NaCl, Na2SO4, Na3PO4, MgCO3, and CuCO3 had no effect on the XRD traces of montmorillonite. The time dependence of the Na2CO3-montmorillonite interaction at 550°C suggested that the reaction is diffusion controlled in three dimensions, i.e., diffusion was directed from the surface of the particle towards its center.

The hydrolysis and decomposition of M-hectorite (M being Na, Li, Mg, or Ca) in dilute solutions of M-chlorides were studied by recording the changes in electrical conductivity (EC) of the clay suspensions with time, and by chemical analyses of the interclay solutions and resulting solid phases. The rate of hydrolysis of the hectorites in suspension, as evaluated by the change of EC with time, was found to decrease with increase in salt concentration (to zero for Na-hectorite in NaCl concentration of 47 meq/liter), and to decrease with increase in the valency of the adsorbed cation (the rate of hydrolysis of Ca-hectorite was one sixth of that of Na-hectorite). The rate of Na-hectorite hydrolysis was determined by the concentration of protons at the clay surface as calculated from the diffuse double layer theory.

Conversely, in suspensions of Al-hectorite saturated with Na, the hydrolysis rates were not dependent on the electrolyte concentrations. This result can be explained by assuming that the hydroxy-Al polymers at the clay surface determine the proton concentration at the clay surface. Hectorites saturated with structural cations (such as Mg and Li) are chemically more stable than those saturated with Na and Ca. The presence of Li and Mg at the clay surface slowed down the diffusion release of these octahedral ions to the clay surface, compared with Na and Ca hectorite, respectively.

The interaction between N-methyl 8-hydroxy quinoline methyl sulfate, a drug that absorbs erymathogenic near-ultraviolet radiation, and smectite was studied by X-ray powder diffraction (XRD) and adsorption and desorption techniques. From the adsorption studies, (1) the amount of the drug adsorbed by Na-smectite increased with the pH of the solution to pH 6.5 and then decreased as the pH was further increased; (2) the maximum amount adsorbed at pH 6.5 was 102 meq/100 g of clay; and (3) the maximum amount of drug adsorbed, according to the adsorption isotherms at pH 4, was close to the cation-exchange capacity of the smectite (80 meq/100 g). The XRD studies showed that the drug molecules were adsorbed in the interlayer space of smectite and that cation exchange was the chief mechanism responsible for these interactions. The results of the adsorption-desorption cycles of the drug by smectite showed that this clay is a good support for this compound. In addition, an alternative method was developed to obtain the intercalation compound to avoid the standard method of exchange by impregnation. The method consisted of grinding a mixture of the drug with the clay. The characteristics of the complex thus formed were similar to those of the complex formed by exchange at pH 4 to 7.

To gain insight into the pharmacological properties of the intercalation compound studied, its capacity for absorption of visible and near-ultraviolet light was investigated. The diffuse reflectance spectrum of the complex showed intense absorption bands, absent or weak in the spectra of the pure drug or the untreated clay, at 250, 290, and ~390 nm.

A quest for meaning characterizes the thought of this century everywhere in humanistic studies, and it is a quest justified by exploring and mapping old and new terrains of which the resources are still uncertain. The Monastery of Escorial today raises so many questions about the traditional ideas with which we treat the history of art in the sixteenth century, that they are the subject of this paper. It is in four parts: the Escorial as Mannerism; as estilo desornamentado, as Renaissance magic; and as an application of the aesthetic system of Saint Augustine.

Our present models and theories of African history and prehistory are profoundly influenced by the physical anthropologists’ perceptions of human reality in present-day Africa. Professor P. V. Tobias has suggested that the present-day people of Africa, excluding the recent arrivals from Europe and Asia, descended from a common proto-Negriform stock which gave birth first to the so-called “Khoisan” (I am using here the terminology of my source, not the historically justified Khoe and San, meaning the Hottentots and the Bushmen) and later to the Negro genetic type. Of greater importance to archaeologists, who deal mainly with the so-called pre-history, is the fact that, genetically speaking, the difference between the “Khoisan” and the Negroids is smaller than the difference between these two African racial types and all other non-African types. This realisation tends to have one consequence: the pre-historic and even historic developments are generally perceived as explainable from within Africa, without any need for external clues or explanations. Archaeological finds are thus taken for evidence of a basically internal evolution and the finds of foreign glass beads, though very frequent and spread all over Africa, are seen as belonging to the same category as Persian, Chinese, or Arab ceramics and are explained as indication of a coastal trade.

The endowment of religious, charitable, and educational enterprises by the establishment of trusts in land, the income from which could be devoted to such uses, was an immensely popular form of pious expression in both medieval Christendom and the Islamic world. The motives for, and applications of such endowments differed markedly, however, between the two religious cultures. The endowment of prayers and masses for beneficiaries, living and dead, exemplified the sacramental and sacerdotal quality of pre-Reformation Christianity. This ritualistic and ecclesiastical use of endowments in Latin Christian Europe and the Orthodox East, a use dependent on the existence of a sacramental system and an institutional church, contrasted sharply with the broader application of the Muslim waqf, by means of which pious individuals and groups sponsored a wide variety of charities, explicitly life-oriented and quite unconnected with a corporate clerical establishment. The infinite multiplication of private acts of charity by devout Muslims manifested the moralistic bent of Islam, which aspired to recast society according to the norms of the Qur'an and sacred law. The contrasting uses to which the two religious systems put the gifts and legacies of the faithful reflected the operation of fundamentally different religious premises, whereas the institutionalization of these premises in a shared legal fiction, the trust, assured their enforcement in society and life.

Brain functions are stochastic processes without intentionality whereas mind emerges from brain functions as a Hegelian “change from quantity”, that is, on the order of 1012 profusely interconnected neurons, “into a new quality”: the collective phenomenon of the brain's self-experience. This self-referential and self-observing quality we have in mind is capable of (recursively) observing its self-observations, i.e., interpreting change that is meaningful in relation to itself. The notion of self-interpretation embodies the idea of a “hermeneutic circle”, that is, (in interpretation theory) the treatment of the whole in relation to its parts.

Within collective epistemology, there is a class of theories that understand the epistemic status of collective attitude ascriptions, such as “the college union knows that the industrial action is going to plan” as saying that a sufficient subset of group member attitudes has the relevant epistemic status. I will demonstrate that these summativist approaches to collective epistemology are incompatible with epistemic permissivism, the doctrine that a single body of evidence may rationalize multiple doxastic attitudes. In particular, we can use epistemic permissivism to generate so-called divergence cases, which demonstrate situations in which rationality requires group-level and member-level attitudes to diverge.

Rarely is the problem of the diversity of languages taken into account whenever population groups are formed into States. When the problem does come up, it is later, in a primarily political context which tries to find political solutions, such as we may presently see them in Canada or in Belgium for instance. These solutions are few and they deal with situations that may contain a host of nuances.

Certain countries have chosen a vehicular language while keeping their local languages: the common language in the USSR is the language of one of its republics. In Senegal it is French, which is of a totally foreign origin but has the advantage of avoiding the rivalry existing among the native languages, and it also has a place within the international community. Other countries have accepted as official languages the different languages spoken within its borders. Thus Switzerland is officially tri-lingual (French, German, Italian), giving legal status to what somewhere else may simply be an accepted fact. Many Alsatians speak three languages (Alsatian, French, German). As far as it concerns countries with a strong linguistic heterogeneity, whether it be their history or their size making for a centralizing policy, they have adopted, with the resulting neglect of all others, the language or the idiom of the region which was politically or culturally the dominant one at the time of their unification. Pekinese has been extended to all of China, Florentine to Italy, Hindi to India. Some original combinations can be found: in Israel Jewish immigrants who came from more than seventy different countries, have again taken up the nation's old cultural and religious language, which had been out of use for two thousand years, and have placed it on equal footing with Arabic spoken by the local population, while English is being used for international relations.

Core KM-3 at Searles Lake, California, comprises 693.4 m of lacustrine sediments deposited over the past 3.2 m.y. The lake water evolved from moderately saline, slightly alkaline, and dominated by Na, Ca, Cl, SO4, and HCO3 + CO3 to a highly alkaline brine dominated by Na and CO, ions. Sediments are chiefly muds and evaporites. Montmorillonite and illite are the principal detrital clay minerals supplied to Searles Lake at present and probably during the late Pliocene and Pleistocene.

The drill core is divided into three diagenetic zones on the basis of clay-mineral reactions. The upper zone (0-291.1 m) contains authigenic Fe-illite, Mg-smectite, K-feldspar, and analcime, which average 60–70% of the <2-μm silicate fraction of mud samples. The principal silicate reactants are detrital montmorillonite and kaolinite, which have been largely consumed. The middle zone (291.1–541.6 m) also contains authigenic Fe-illite, Mg-smectite, K-feldspar, and analcime, but they form only 20 to 30% of the <2-μm silicate fraction, and considerable detrital montmorillonite and kaolinite remain unaltered. In muds of the lower zone (541.6–693.4 m), a small amount of clinoptilolite is the only authigenic silicate mineral identified, although authigenic montmorillonite probably coexists here as well. Vitric ash is the silicate reactant, and detrital clay minerals apparently remain unaltered in the lower zone.

Diagenetic zoning reflects the pore-water chemistry, in which pH may have been the most important parameter. Sediments of the upper zone were deposited in highly alkaline lakes of variable salinity, and sinking brines with a pH of 9.0–10.0 have saturated all sediments. Sediments of the middle zone were deposited in lakes of moderate to high salinity. The pH was overall lower than in the upper zone, although it probably exceeded 9.0, at least locally, during silicate diagenesis. Moderate salinity and a slightly alkaline pH (~ 7.5–8.0) are inferred for both the lake and pore water of the lower zone.

Oxygen-isotope values of authigenic Fe-illite, Mg-smectite, and K-feldspar, and phillipsite in the upper diagenetic zone reflect a high degree of evaporative concentration and presumably of salinity. Equilibrium water values calculated for 22°C from the oxygen-isotopic composition of authigenic phyllosilicates range from −3.5 to +1.9%, averaging −1.2% (SMOW). Higher salinities are suggested for K-feldspar, for which water values range from +1.8 to +4.8%, averaging +3.4‰ The water value for phillipsite is +0.3‰ By comparison, rainfall at Searles Lake has an average δ18O value of about −9.8%, and a brine sample has a value of +4.0‰

Mud samples of the middle and upper diagenetic zones tend to be rich in Fe-illite or Mg-smectite, but not in both, indicating that the two minerals are favored to some extent by different environments. Fe-illite seems to be generally favored by oxidizing conditions and probably by a playa environment, and Mg-smectite seems to be favored by reducing conditions and an open-water environment. One strati-graphic unit of the upper zone does not fit this pattern and contains abundant Fe-illite in sediments of a deep perennial lake.

In so far as the Tao Te Ching and the Chuang Tzu are life-philosophies, they are philosophies of solitude. My aim in the following pages is to explain and defend this claim, clarifying the distinctive kind of solitude that is taught by Lao Tzu and Chuang Tzu.

Hydrotalcite-like compounds, [Mg1-xAlx(OH)2]x+ [xX−·n H2O], where X− = ½CO32− or OH−, were prepared by hydrothermal syntheses at $P_{H{}_{2}O}=100MPa$ and T = 100°–350°C. Starting materials were MgO, γ-Al2O3, H2O, and MgC2O4·2H2O. The synthesis depended on temperature, pressure, the Al/(Al + Mg) ratio x, and the CO2 content of the starting material. Previously an Al content of x = 0.33 was thought to be the upper limit in these double-layer compounds, but by using pressure the Al-content was increased to x = 0.44. Up to x = 0.33, a0 decreased linearly to about 3.04 Å, but for x ≥0.33, a0 remained nearly constant at this value. For the synthesized products the layer thickness c’ varied between 7.40 and 7.57 Å in contrast to the natural phases wherein c’ varies from 7.60 to 7.80 Å. At higher temperatures CO2-free syntheses, i.e., those without Mg-oxalate, resulted in a disordered hydrotalcite-like phase. The transition temperature between the ordered and the disordered hydrotalcite-like phase depended on the Al-content, x.

Synthetic Al-hematites prepared from ferrihydrites, at low (∼ 100°C) and high (400° and 800°C) temperatures were studied for their morphological, crystallochemical, and infrared (IR) characteristics. Low-temperature Al-hematites had a platy morphology (the plate thickness was inversely related to amount of Al substitution), and the high temperature Al-hematites showed a poorly defined morphology due to interparticle sintering. In the low-temperature Al-hematites shifts in the IR mode frequencies were noted and could be partly explained by a shape factor that was deduced from particle morphology. The intrinsic effect of Al substitution, however, was to produce shifts of as much as 10–15 cm−1 for the highest Al substitution (∼ 16%). Similar shifts were observed for the high-temperature hematites in which morphology was not appreciably affected by Al substitution.

Several new, room-temperature luminescent phenomena, resulting from the interaction of kaolin and various amino compounds, have been observed. The emission of light from kaolin pastes (treated with quinoline, pyridine, hydrazine, monoethanolamine, n-butylamine, and piperidine) was shown to decay monotonically over a period of hours to days. More light was released by a given amino compound after it was dried and purified. Hydrazine, in addition to the monotonically decaying photon release, produces delayed pulses of light with peak emission wavelength of 365 nm which last between several hours and several days. These photon bursts are acutely sensitive to the initial dryness of the hydrazine, both in the number of bursts and the integrated photon output. The amount of light and the capacity of the kaolin to produce the delayed burst appeared to be strongly dependent on preliminary heating and on gamma-irradiation, analogous to the dehydration-induced light pulse previously reported from the Ames Research Center. A small, delayed burst of photons occurred when piperidine and n-butylamine were removed by evaporation into an H2SO4 reservoir.