The effects of surfactants on bentonites have been of great scientific interest for many years. Even though quaternary alkylammonium salts (QAS) have been studied, very few data are available on the comparative performance of different chain-length QAS for the modification of the surface properties and adsorption properties of bentonites. The objective of this study was to investigate the effect of chain length on the adsorption of cationic surfactants onto bentonite. The surface and adsorption properties of different chain-length QAS, i.e. hexadecyltrimethylammonium bromide (HTAB, C16), tetradecyltrimethylammonium bromide (TTAB, C14), and dodecyltrimethylammonium bromide (DTAB, C12), to produce organo- bentonites (OB) were studied. The concentrations of QAS were selected based on the cation exchange capacity (CEC) of the clay mineral. Zeta potential, swelling, and viscosity measurements and scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) analyses were used to explain the changes in surface properties. The results indicated that the best modification of bentonite was obtained using a 16-carbon chain length QAS (HTAB) in a 1:1 ratio of QAS to CEC. The basal spacing at this concentration was measured to be 22.19 Å, which also corresponded to the maximum adsorption density. The OB produced at this concentration showed the best hydrophobic character based on the swelling tests in toluene. The extent of hydrophobicity and adsorption density was correlated with the CEC and alkyl chain of the QAS. All these properties were used to elucidate the mechanism of modification governing the bentonite/QAS system.

The present study describes research carried out to evaluate the mineralogical, geochemical and technological properties of indurated shale-quarry wastes and assess the suitability of these low-cost and locally available quarry wastes generated from crushed indurated shales for possible use as alternatives to fresh raw materials in the manufacture of roofing-tile products. Firstly, the mineralogical and chemical properties of the indurated shales were investigated by X-ray diffraction (XRD) and X-ray fluorescence, while their physical properties were identified by grain-size distribution, Atterberg limits, and clay activity. Samples of indurated shale-quarry wastes (ISQWs) were subjected to heat treatment at elevated firing temperatures to provide the required strength and durability and their ceramics properties (linear shrinkage, weight loss, water absorption, bulk density, and flexural strength) were determined. From the results, the ISQWs were composed predominantly of fine particles with medium plasticity and clay activity with values generally >0.75. The mineralogy revealed a predominance of aluminosilicates (illite-kaolinite-smectite-chlorite) with large quartz contents and variable percentages of carbonate and feldspar. The oxides were dominated by SiO2 and Al2O3, small amounts of ferromagnesian minerals, and considerable amounts of alkalis (K2O and Na2O) which act as fluxes. The CaO concentrations were variable and related to carbonate contents. Characterizations based on compositional ternary (total clay mineral-carbonate-quartz + feldspar) systems, Casagrande clay workability charts, and Winkler and McNally diagrams revealed their suitability for ceramics applications as the majority of ISQW samples fell within the specifications for roofing tiles. The ISQWs fired at a high temperature of 1000°C revealed considerable weight loss, reduction in both linear shrinkage and water absorption with insignificant increase in flexural strength. In order to achieve excellent ceramics properties and further reduce sintering temperature for their suitability as raw materials in the production of roofing tiles, beneficiations of ISQWs are highly recommended.

Authigenic analcimes were observed in different amounts in Miocene units in central Anatolia, Turkey. Two types of analcime occurrences were defined: (1) as continuous but inhomogeneous concentrations varying from 3 to 75 wt.% in lacustrine sedimentary rocks; and (2) as low concentrations (between 3 and 20%) and discontinuous components in the tuffs and claystones intercalated with tuff. The type 2 analcimes have been investigated by many researchers while the origin and properties of the sedimentary analcimes, which are widespread in different parts of Turkey, have not been clarified. The present study focused on the genesis and the mineralogical and geochemical properties of both types of analcime. The analcimes were investigated using X-ray diffraction, optical microscopy, scanning electron microscopy, and chemical analytical methods. In the first type, other than volcaniclastic material, analcime is the only zeolite mineral. The first type of analcime was associated mainly with montmorillonite, dolomite, and feldspar and sometimes with calcite, and rarely with illite and kaolinite. The second type of analcime was found as an accessory mineral accompanied by montmorillonite, feldspar, and heulandite/clinoptilolite, and more rarely by erionite, kaolinite, and mica. The pyroclastic rocks are chemically classified into two subgroups, dacitic and andesitic rocks, with an intermediate to high silica content and a high percentage of alkali cations. Analcime in the pyroclastics intercalated with clay layers commonly replaced early-formed zeolites, such as clinoptilolite or volcanic materials. The first type of analcime was not formed from precursor zeolites and had a different origin than the second type. Type 1 analcime contains larger amounts of Si (34.19 to 34.68 Si per unit cell) and less Al and Na than in theoretical analcime. The theoretical structural formula of analcime is Na16(Al16Si32O96)H2O. The strongly decomposing feldspar and clay minerals (in particular montmorillonite and partially illite) of the older formations and the dissolution of halite and also soda minerals, e.g. thenardite and glauberite, allow the authigenic formation of type 1 analcime, dolomite, K-feldspar, and montmorillonite in a saline and highly alkaline environment such as the marginal part of Lake Tuzgölü. Type 2 analcime may have been precipitated directly from solution, pyroclastic material, or precursor zeolite minerals in saline and alkaline lake water.

This paper presents a novel concept in the thermodynamic derivation of phase diagrams for clay minerals that incorporates fuzzy transition zones. This new technique yields phase diagrams that have graded (fuzzy) zones of mineral occurrences and includes compositional variability within mineral groups. For the construction of these diagrams, 170 minerals belonging to nine different subgroups were used, based on a fuzzy mathematical description of their ‘grades’ or ‘belonging-ness’. Standard free energies of formation of all the minerals were derived and all possible pairs of mineral equilibria were evaluated. Relative intensities of mineral occurrences were determined and membership values of each type of mineral at various zones in a 2D or 3D space were graphically represented. Computations and graphical representations were carried out using programs developed in Mathematica. Diagrams were derived for 25°C, 1 bar with a solution phase containing Si(OH)4, K+, Na+, H+, Ca2+ and Mg2+ under conditions of gibbsite, goethite and ferrous oxide saturation. The resulting diagrams, unlike conventional phase diagrams, show multimineral assemblages, with varying occurrences of different minerals and provide a realistic representation of clay mineral occurrences formed by surface geochemical processes. They show that on the Earth’s surface, only montmorillonite can almost completely predominate the inorganic phase followed by kaolinite, illite and beidellite. Nontronite, glauconite, celadonite and vermiculite would not be neoformed in substantial amounts. A general conformity of derived phase equilibria with experimentally observed equilibria is also observed.

The benefits of using kaolin as a source of aluminosilicate in zeolite synthesis to obtain lowercost catalysts, adsorbents, or ion exchangers are widely known. Previous attempts to produce zeolite from natural Iranian kaolin resulted in the formation of zeolites A, X, and HS. Zeolite Y plays an important role in the petrochemical industry due to its application in the area of fluidized catalytic cracking; ~40% of gasoline production is obtained using this process.

In the present study, different methods were used to prepare pure zeolite NaY from the Iranian kaolin available. The effects of different parameters such as aging time, crystallization time, kaolin calcination and crystallization temperature, and starting-material composition were investigated in order to obtain improved properties and maximize phase purity. In all cases, the crystal structure and microstructure were studied using X-ray diffraction and scanning electron microscopy. Among different synthesis approaches, the ‘guide-agent method’ resulted in the formation of zeolite NaY. The synthesis was generally sensitive to changes in kaolin calcination temperature and in hydrothermal synthesis parameters. The optimum parameters to prepare pure zeolite NaY were: kaolin calcination temperature = 680°C, aging time of guide agent = 48 h without an overall gel aging step, and crystallization at 90°C for 36 h.

Apophyllite, a hydrous K-Ca-phyllosilicate, reacts with acidic aqueous solutions at room temperature. Various analytical methods have been applied to study the mechanism of the reaction and its characteristics, i.e. the changes in chemical composition, modifications in crystal structure and alterations in surface morphology. In contact with acidic solution, protonation of the terminal, non-bridging oxygen at the silicate tetrahedra takes place and the interlayer cations K+ and Ca2+ are removed. The protonation and ion removal causes the interlayer spacing to increase. Atomic force microscopy shows that the increase takes place discontinuously and, therefore, reflects a discontinuous reaction that comprises a two- or three-step protonation. Additionally, three structurally different protonation sites have been detected by nuclear magnetic resonance spectroscopy which also differ in the amount of close-by hydrogen, although in pristine apophyllite all terminal oxygen positions at silicate tetrahedra are structurally equivalent. In many clay minerals such structurally different protonation sites have not been detected so far. Thus, the multi-step protonation process in apophyllite clearly demonstrates the vast sensitivity of the protonation reaction on small structural variations in phyllosilicates.

The University of Nanking, established in 1910 by missionaries from the United States and built between 1912 and 1931, was one of the earliest Christian universities established in China. Its campus in Nanjing, in China’s eastern Jiangsu province, featured a combination of Beaux-Arts plan, local Chinese architectural styles and modern building techniques that both responded and contributed to rapid changes in the city’s socio-political context during the early twentieth century. Identifying and examining three trends in the planning and architectural design of the campus — westernisation, localisation and modernisation — this article argues that the university was actively involved in the transition of Nanjing from a regional urban centre of the Qing dynasty to the new capital of the Chinese republic (1912–49). The interaction of the three trends illuminates how a Chinese Christian university, as a new type of institution without parallels in traditional Chinese society, used western and Chinese theories and resources to produce modern educational space. The university’s efforts to modernise in the face of Nanjing’s then poor urban infrastructure and nascent building industry happened at various levels from infrastructure to tectonics, often achieved through the collective efforts of the western superintendent and Chinese workers and contractors. Influencing later attempts to modernise urban space and to develop a new architecture suitable for the new era in the country, the project represents a transitional moment in the architectural history of modern China when the cross-cultural exchange of knowledge between east Asia and the west brought new possibilities to Chinese buildings and cities.

Smectites are considered to be an important component in backfill barriers due to their marked swelling and high cation exchange capacity. Both properties are affected considerably when these clays transform under natural conditions. However, we have recently described a chemical interaction between high-activity radionuclide simulators and smectites which could prove to be effective at immobilizing radionuclides definitively. Investigating the efficiency of this mechanism, independent of bentonite ageing, is a challenge. For this purpose, the reactivity shown by a non-expandable layered aluminosilicate, muscovite, has been compared to that shown by an expandable one, beidellite. Both samples were treated hydrothermally with a solution of lutetium nitrate, and the transformations were studied by X-ray diffraction, nuclear magnetic resonance and scanning electron microscopy/energy dispersive X-ray analysis. Lutetium cations react with the silicon framework of both 2:1 layered aluminosilicates under hydrothermal conditions, and new phases, lutetium disilicate, kaolinite, boehmite and natrosilite are generated. The results demonstrate that the efficiency of the chemical mechanism is not determined by the swelling and the cation exchange capacity of 2:1 layered aluminosilicates. Thus, the rare earth disilicate formation might account for the success of the clay barrier, once bentonite has lost its swelling and cation exchange capacity.

Lattice dynamic calculations for the sepiolite and palygorskite structures using polarized Raman and FTIR spectra provide a fundamental basis for interpreting spectral features by assigning vibrational modes. The Si-O stretch and O-Si-O bond bending force constants determined for palygorskite are similar to equivalent values calculated previously for other phyllosilicates. The Mg-O bond stretch values, on the other hand, are about half of those determined for the equivalent Al-O and Mg-O bond stretch environments in other phyllosilicates, suggesting that the bonding within the octahedral ribbons in palygorskite and sepiolite is weaker than that in the continuous octahedral sheets in micas. The weaker bonding allows more flexible octahedral environments in palygorskite and sepiolite, giving rise to higher probabilities for cation substitutions and vacancies relative to the micas. Above ∼700 cm−1 in the IR and 750 cm−1 in the Raman spectra, the eigenmodes are dominated by atomic displacements within the silicate sheets. Below 700 cm−1 the eigenmodes become mixed with motions among the Mg octahedra and the silicate sheets; the eigenmodes assigned to the most prominent peaks in the Raman spectra (near 700 cm−1) belong to this group. As mode frequencies decrease, the corresponding eigenmodes evolve from more localized Mg-O stretch, O-Mg-O bend and O-Si-O bend motions to longer-range motions such as silicate sheet deformations caused by silicate tetrahedra rotation and silicate sheet shearing around the Mg-octahedral sheets.

In the late eleventh century, Goscelin of Saint-Bertin (ca. 1040–d. after 1099) composed the most extensive collection of hagiographical writings known to have been assembled for a community of religious women in medieval England. At the behest of Abbess Ælfgifu (ca. 1037–ca. 1114) of Barking Abbey, he definitely wrote the following texts to honor the community’s three principal saints: a uita of its founder and first abbess, Æthelburh (d. after 686); Matins lessons for her immediate successor, Hildelith (d. after 716); a uita and an account of the first translation of their later tenth-century successor Wulfhild (d. after 996); Matins lessons and a longer account of the three abbess-saints’ translation on Laetare Sunday, 7 March 1092; and a report of a vision Ælfgifu received seven years after the event. This article makes the case for Goscelin’s authorship of the Matins lessons for Sts. Æthelburh and Wulfhild as well, and for their preservation in London, British Library, Cotton MS Otho A XII (Part 6). Paleographical analysis of these lessons further indicates that the scribe responsible for copying them also copied the lives of Sts. Æthelburh and Wulfhild in Dublin, Trinity College, MS 176 (E.5.28), a late eleventh-century book of Barking origin. This hand exhibits features peculiar to scribes trained in northeastern France or the Low Countries, raising the possibility that Goscelin made these copies himself. But even if he did not make them, the appearance of the same hand in texts related to Barking’s abbess-saints suggests that this scribe’s work in Otho A XII (Part 6) should be located at Barking, too, thus increasing the total number of books the community once owned to twenty-two and further proving one of the instrumental roles that religious women played during the Middle Ages to orchestrate their communities’ liturgies: commissioning writers and scribes to compose saints’ lives, Matins lessons, and other texts and music to celebrate their principal feast days with due solemnity and distinctiveness.

Although fluorescence detection is a sensitive method in the field of pollutant analysis, its application is restricted due to the fluorescence shown by organic material being quenched after aggregation and to low photo-thermal stability. To address these issues, a novel mineral/dye composite material was prepared by intercalating a fluorescence molecule, Rhodamine (R6G), into the interlayer space of montmorillonite (Mnt). This composite material greatly enhanced the light stability and efficiency of R6G. After enhancement, the fluorescence lifetime of R6G-Mnt was eight times longer than originally and the luminous intensity was 20 times greater. Chromium at the mmol/L (mM) level can be detected by the naked eye when its enhanced fluorescent property is fabricated into a solid test paper, even though a fluorescence spectrophotometer should be used for detection at the 0.01 μmol/L level in the sensing range 0.01 μmol/L to 100 mmol/L. These results can provide new avenues as well as a theoretical and experimental foundation for the development of novel supramolecular luminescent material.

The cation exchange capacity (CEC) is a characteristic property of expandable clay minerals, such as smectites and vermiculites. The aim of this work was to examine the cation exchange behavior of vermiculite using the Cu-triethylenetetramine (Cu-trien) CEC method and the influence of mechanical and chemical pretreatment, with the ammonium acetate method serving as a reference. The Cu-trien method makes rapid and direct CEC measurements possible. Three different kinds of mill were used to grind a vermiculite sample from Russia, in order to reduce the particle size to <10 µm. The Netzsch CGS 10 dry mill reduced the particle size more effectively than the other grinding methods. Chemical pretreatments were used to remove carbonates, organic matter, Fe oxides, and divalent exchangeable cations from vermiculite samples prior to CEC measurements. Subsamples of ground and chemically pretreated vermiculite samples were saturated with Na, Li, Mg, Ca, and Cu cations to determine the effect of exchangeable cations on measured CEC values. Chemical pretreatment, monovalent cation pretreatment, and 48 h of shaking time were needed to measure vermiculite CEC values effectively using the Cu-trien method.

During the Gilded Age and Progressive Era, thousands of middle-class youths published their own amateur newspapers. These periodicals were printed using the so-called toy (or “novelty”) press, a portable tabletop device that helped democratize word processing. Children often used their presses to compose miniature novels and short stories. They then shared their prose with a national community of fellow juvenile writers collectively known as “Amateurdom.” Adolescent fiction explored an array of subjects, but the frontier, territorial expansion, and empire in the West became some of its particular fixations. All that imperial storytelling, however, possessed a rich subtext. Boys and girls, reacting to late-nineteenth-century changes in the lived experience of childhood, used their printing presses to challenge various constraints imposed upon them. But in so doing, they both perpetuated and reinforced a pernicious culture of settler colonialism that celebrated the subjugation of American Indians. Ultimately, the amateur publications of children remind us that fiction is not exclusively an adult enterprise. The creative output of young people provides important insight into an underexplored realm of the Gilded Age and Progressive Era’s literary world.

Microstructural changes induced by the microbial reduction of Fe(III) in nontronite by Shewanella oneidensis were studied using environmental cell (EC)-transmission electron microscopy (TEM), conventional TEM, and X-ray powder diffraction (XRD). Direct observations of clays by EC-TEM in their hydrated state allowed for the first time an accurate and unambiguous TEM measurement of basal layer spacings and the contraction of layer spacing caused by microbial effects, most likely those of Fe(III) reduction. Non-reduced and Fe(III)-reduced nontronite, observed by EC-TEM, exhibited fringes with mean d001 spacings of 1.50 nm (standard deviation, σ = 0.08 nm) and 1.26 nm (σ = 0.10 nm), respectively. In comparison, the same samples embedded with Nanoplast resin, sectioned by microtome, and observed using conventional TEM, displayed layer spacings of 1.0–1.1 nm (non-reduced) and 1.0 nm (reduced). The results from Nanoplast-embedded samples are typical of conventional TEM studies, which have measured nearly identical layer spacings regardless of Fe oxidation state. Following Fe(III) reduction, both EC- and conventional TEM showed an increase in the order of nontronite selected area electron diffraction patterns while the images exhibited fewer wavy fringes and fewer layer terminations. An increase in stacking order in reduced nontronite was also suggested by XRD measurements. In particular, the ratio of the valley to peak intensity (v/p) of the 1.7 nm basal 001 peak of ethylene glycolated nontronite was measured at 0.65 (non-reduced) and 0.85 (microbially reduced).

What are the distributional consequences of migration, and how do they affect attitudes toward migration? In this paper we leverage a natural experiment generated by the ousting of former Libyan dictator Muammar Gaddafi, which created an unprecedented influx of economic migrants from African countries to Europe. This surge of low-skilled labor benefited low-productivity firms by lowering their production costs and expanding their labor supply. Employing a triple difference-in-differences design, we document that attitudes toward migration became more positive in Western European regions with large shares of migrants and low-productivity firms. Evidence from Sweden, which provides finely grained geographical data, confirms these findings. We then test the economic microfoundations of this attitudinal shift. We show that the surge in the supply of low-skilled labor increased the profitability of low-productivity firms more in areas that experienced larger migration flows. We find no evidence that migration worsened natives’ labor market conditions.

We used high-resolution X-ray texture goniometry to quantify changes in the mm-scale orientation of phyllosilicate minerals in a suite of Paleogene mudstones from the Podhale Basin in southern Poland. The sample set covers an estimated range of burial depths between 2.4 and 7.0 km, corresponding to a temperature range of 60–160°C. Although mechanical compaction has reduced porosities to ∼10% in the shallowest samples, the phyllosilicate fabric is only modestly aligned. Coarser-grained (>10 µm) detrital chlorite and mica appear to be more strongly aligned with (001) parallel to bedding, suggesting their deposition as single grains rather than as isotropic flocs or aggregates. From 2.4 to 4.6 km, R0 illite-smectite with 40–50% illite layers changes to R1 illite-smectite with 70–80%) illite layers. At the same time kaolinite is lost and diagenetic chlorite is formed. The mineralogical changes are accompanied by a strong increase in the alignment of illite-smectite, chlorite, and detrital illite, parallel to bedding and normal to the presumed principal effective stress. We propose that the development of a more aligned I-S fabric results from the dissolution of smectite and the growth of illite with (001) normal to the maximum effective stress. Water released by illitization may act as a lubricant for the rotation of all platy minerals into nanoporosity transiently formed by the illitization reaction. At greater depths and temperatures, further illitization is inhibited through the exhaustion of K-feldspar. After the cessation of illitization, a further 2.4 km of burial only results in a small increase in phyllosilicate alignment. At such small values for porosity and pore size, increasing stress does not substantially reorient phyllosilicates in the absence of mineralogical change.

Particle-size analysis (obtained by Galai CIS 1) was used to determine the following statistical parameters of aqueous suspensions of Na-, Ca- and Mn-montmorillonite: the size distributions, the diameters of the largest and of the median and mean particles, and the percentage of particles with diameters <1.5 µm. Dilution or shaking had almost no effect on the particle-size distribution curves and statistical parameters of Ca- and Mn-montmorillonites but the curves and the statistical parameters of Na-montmorillonite were very much affected by these treatments. The median and mean diameters of Na-montmorillonite range from 0.8 to 10.5 µm and 0.8 to 11.6 µm, respectively, the median and mean diameters of Ca-montmorillonite range from 1.5 to 3.6 µm and 2.12 to 4.2 µm, respectively, and those for Mn-montmorillonite from 1.2 to 2.3 µm and 1.5 to 2.5 µm, respectively. The presence of large particles of Na-montmorillonite was attributed to the extensive swelling of this clay in aqueous suspensions by osmotic water adsorption. The median and mean diameters of aged Na-montmorillonite suspensions indicate that swelling increases with dilution. The swelling of Ca- and Mn-montmorillonite, on the other hand, is limited and their particle size does not increase with dilution.