Acidified suspensions of Al-saturated kaolinite, montmorillonite, mica, illite, and biotite in 10−3 M NaNO3 were potentiometrically titrated with 0.1 N NaOH and 0.1 N HNO3 in succession in a CO2-free nitrogen atmosphere. The resulting curves were compared with those for Al(NO3)3 solutions of similar Al concentration in the supernatant solution and corrected for Al in the entrained solution in the clay.

Base titrations of Al ions adsorbed on all the minerals, except montmorillonite, showed two pH inflections separated by a buffering range. With montmorillonite, there were three pH inflections similar to those for Al in solution. The first inflections in the titration of suspensions occurred at lower pHs and were less pronounced than for Al in solution. These represent the titration of H3O+ sorbed during the pretreatment. The buffering by adsorbed Al ions is also less than that by Al in solution.

The OH− used up by adsorbed Al ions between the first and last inflections was equal to, or slightly greater than, the CEC of the minerals, except for mica where it was more than twice the CEC, because new interlayer surfaces were formed during the acid pretreatment. Acid titration curves of Al ions in the adsorbed and solution states showed hysteresis when related to the base titration curves. The use of two titration speeds (3 and 0.3 pH units/hr) only slightly affected the titration curves of the minerals suggesting that the observed effects were not caused by lack of equilibrium with added base or acid.

Deviations in the symmetry of mica single layers from the ideal arrangement with all atoms in hexagonal arrays are caused by the structural factors such as compositional variation (substitutions), order-disorder, and distortions. The derivative crystal structure theory as applied to mica polymorphism, implies that the ideal symmetry of the mica single layer (C2/m) can be altered to one of its standard subgroups by these structural factors. The “derivative structure” of the single layer may allow a unique interlayer and a specific intralayer configuration and result in a regular stacking sequence.

A simple electrostatic model has been used to demonstrate that the inner surface hydroxyls in kaolinite, dickite and nacrite are responsible for the interlayer bonding in these minerals. The contribution to the interlayer bonding of an individual hydroxyl hydrogen depends on the orientation of the hydroxyl group relative to the 1:1 layer since this orientation determines the H—O interlayer distance. If this distance is much greater than the sum of the van der Waals radii, 2·60 Å, there is essentially no bond. As the distance becomes less than 2·60 Å, the strength of the interlayer bond increases.

Clay minerals from shale outcrops of the Lower Cretaceous Buckinghorse Formation (4250 ft thick) were investigated in order to assess their degree of diagenesis and their oil-generating potential. Crystallinity index, sharpness ratio, per cent of illite which is the 2M polymorph and presence of discrete minerals have been studied in the whole clay fraction, while the very fine clay fraction has been subjected to X-ray diffraction, differential thermal, thermogravimetric, differential thermogravimetric, i.r. spectroscopy, surface area and chemical analyses. With information derived from these studies and from published data, a classification scheme was devised which relates variation of clay mineralogy to diagenetic stages and burial depth.

Data on the < 2 μm size fraction show that the crystallinity index decreases while the sharpness ratio and per cent of illite which is the 2M polymorph increase with burial depth. Results on the <0·08 μm fraction reveal that a three-component interstratified clay mineral exists. In addition, Fourier transform calculations and chemical and physicochemical analyses indicate that both the ratio of the amounts of non-hydrated clays (illite) to hydrated clays and the K2O content of clays increase with burial depth; cation exchange capacity and surface area decrease with burial depth.

Based upon a classification scheme, which was devised by combining criteria and data derived from the studies of Weaver (1961a), Kubier (1966), Burst (1969) and Dunoyer de Seconzac (1970), the upper and middle parts of the formation (upper 3250 ft) fall within the middle stage of diagenesis whereas the lower part (1000 ft) is allocated to the beginning of late diagenesis. In terms of Burst’s (1969) work, the upper 3250 ft are transitional between the stability and dehydration zones indicating that, prior to uplift, hydrocarbons may have been in the process of migration. The lower 10000 ft of the formation are in the restricted dehydration zone, indicating that hydrocarbon migration should have been completed.

K-saturated kaolinite was titrated in 13 different solvents with tetrabutylammonium hydroxide using a combination electrode for potentiometric determination. The titer of base required to reach the final potentiometric endpoint was dependent on the solvent and increased according to the following solvent order in both the presence and absence of excess neutral salt: methanol ⩽ water < ethanol ⩽ 1-propanol < 1-butanol < 2-propanol < DMF < t-butanol < DMSO < pyridine ⩽ acetonitrile ⩽ methylethyl ketone < acetone. With the protic solvents, titratable acidity increased according to decreasing dielectric constant of the solvent and increasing size and/or branching of the aliphatic constituent. The largest titratable acidities were obtained in the dipolar aprotic solvents with negligible basic character (e.g., acetonitrile, acetone, methylethyl ketone). These results are discussed in terms of solvent properties, solvation characteristics of ions in the solvents, and acid-base behavior of crystalline edge sites.

The influence of pressure on the conductance of frozen montmorillonite suspensions was measured in the temperature range from 0°C to − 12°C on Na- and Ca-saturated samples. Pressures invariably increase the conductance of frozen suspensions. The change in conductance with pressure is postulated to be due to pressure melting of the ice in the frozen suspension. From swelling pressure data the increase in unfrozen water with pressure at constant temperature is calculated and shown to be consistent with the effect of pressure on conductance.

The presence of Al-bearing goethites has been unequivocally established in Venezuelan laterite sediments by means of infrared spectroscopy (IR), chemical dissolution, and X-ray powder diffraction (XRD) methods. The composition of these samples ranges from [Fe0.89Al0.11]O(OH) to [Fe0.76Al0.24]O(OH). The data of dissolution experiments using a modified dithionite (CDB) treatment suggest a parallel behavior between Fe and Al; the gradual dissolution of Al is associated with the destruction of the Al-containing goethite. The interpretation of the CDB dissolution results for SiO2/Fe2O3 is different; silica was only slightly extracted from phases other than goethite. Substitution of Fe3+ by Al3+ in these goethites was represented on the XRD patterns by a lowering of the (110) and (111) reflections corresponding to a reduction in size of the unit cell of goethite. IR spectroscopy showed the formation of such solid solutions by a shift of the 405 cm−1 absorption band, assigned to v (Fe-O) in synthetic goethite, to >460 cm−1 in the spectrum of Al-bearing natural goethite. Moreover, this spectrum shows a shift of the 3140 cm−1 absorption, due to v (OH), to higher frequencies, indicating a H-bond weakening in [FexAl(1−x)]O(OH) compared to FeO(OH).

Sideromelane in Pleistocene lapilli-tuff rocks from the Golan Heights had partly altered into palagonite. X-ray and electron diffraction showed that the major part of the clay alteration product is composed of a dioctahedral micaceous mineral with well organized crystallinity along the a- and b-axes. Very poor basal reflections as well as incomplete expansion upon glycerolation and incomplete collapse upon heating were interpreted as being due to random interstratification with chlorite. Electron microscopy showed the particles to be very similar to montmorillonite tactoids. The thermal behavior as well as surface properties were similar to those of montmorillonite. Differential dissolution analysis and infrared spectroscopy failed to indicate amorphous constituents to any significant extent. Chemically the material was enriched in iron, aluminum and titanium and depleted in alkali and alkaline earth cations.

A minor component of the clay was found to consist of ‘onion-like’ halloysite. It is suggested that palagonite is a natural precursor for montmorillonite in the volcanic glass-montmorillonite alteration series.

Several illites and a mixed-layer illite-montmorillonite developed fractures in some particles during progressive removal of interlayer potassium by solutions containing sodium tetraphenylboron. The appearance of the splinters in bundles, some connected to incompletely broken plates, suggests the process is related to the differential release of stresses known to exist as a consequence of octahedral-tetrahedral misfit. The formation of splinters produces additional surface area for ion removal and may influence the rate of vermiculite development.

We address the unconsciously biased perception of psychiatric disorders, highlighting a hierarchical perspective that favours certain diagnoses over others. We aim to uncover reasons for these inequities, emphasising the need for a shift toward pathophysiology-based nomenclature that can promote equal support for each disorder, enhance treatment adherence and encourage open discussions.

The editorial history of the two Pseudo-Clementine narratives known as the Recognitions and the Homilies is intricate, to say the least. From an ever-elusive “basic writing” spring two novelistic stories with extensive translation histories, subjected to significant editorial interventions, and anthologized alongside other late ancient and medieval texts. This article focuses on the addition of pseudonymous epistles as prefatory material for these Pseudo-Clementines and follows one of these letters in particular, the Epistula Clementis (Ep. Clem.). The Epistula Clementis accompanies the Latin Pseudo-Clementine Recognitions in a host of medieval anthologies concerned with Petrine hagiography and ecclesial succession, as well as histories, dialogues, and epistolary texts with anti-Judaic resonances. I argue that the Epistula Clementis, as a prefatory text, was integral to the success of the Recognitions in these later anthologies, highlighting the transformative power of the preface upon its associated text as well as the hermeneutical force of the anthology itself.

Through a commingled, fragmentary assemblage of skeletal remains (MNI = 9) recovered from a 1999 salvage excavation, this article explores the lives and deaths of individuals interred at the Brentwood Poor Farm, Brentwood, New Hampshire (1841–1868). This work demonstrates that bioarchaeological analyses of smaller samples can provide nuanced accounts of marginalization and institutionalization even with scant historical records. The skeletal analysis presented here is contextualized within the larger history of the American poor farm system and compared to similar skeletal samples across the United States. The hardships these individuals faced—poverty, otherness, demanding labor—were embodied in their skeletal remains, manifesting as osteoarthritis, dental disease, and other signs of physiological stress. These individuals’ postmortem fates were also impacted by status; they were interred in unmarked graves, disturbed by construction, and once recovered, were again forgotten for more than 20 years.

Titanium in TiO2 minerals was differentiated from that isomorphously substituted into minerals by the use of dihydrogen hexafluorotitanate (hydrofluotitanic acid, H2TiF6), which selectively dissolved minerals containing substituted Ti4+, leaving free crystalline TiO2 minerals in the residue. Titanium analyses on the original samples and the residues remaining after H2TiF6 treatment, by both wet chemical (Tiron) and neutron activation methods, indicated that an average of 86 per cent of the titanium in seven kaolinite samples was present in the residual TiO2 form (largely anatase), whereas only 28 per cent in two bentonites was present in the TiO2 form. Residual Ti accounted for 100 per cent of the Ti in synthetic anatase and for 92 per cent of the Ti in coarse clay sized rutile, the latter value suggesting that about 8 per cent amorphous TiO2 was removed from the mechanically dry ground rutile by the H2TiF6 reagent. The Ti present as residual TiO2 in a variety of other samples ranged from 0 to 100 per cent.