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Hydrogen bonding interactions play an important role in many chemical and physical processes occurring in bulk liquids and at interfaces. In this study, hydrous species (H2O and Si-OH) on nano-porous alteration layers (gels) formed on a boroaluminosilicate glass called International Simple Glass corroded in aqueous solutions at pH 7 and pH 9, and initially saturated with soluble silicon-containing species were analyzed using linear and non-linear vibrational spectroscopy in combination with molecular dynamics simulations. The simulation results revealed various possible types of hydrogen bonds among these hydrous species in nanoconfinement environments with their populations depending on pore-size distribution. The nano-porous gels formed on corroded glass surfaces enhance hydrogen bond strength between hydrous species as revealed by attenuated total reflectance infrared spectroscopy. Sum frequency generation spectroscopy showed some significant differences in hydrogen bonding interactions on alteration layers formed at pH 7 and pH 9. The glass dissolution under the leaching conditions used in this study has been known to be ten times faster at pH 7 in comparison to that at pH 9 due to unknown reasons. The simulation and experimental results obtained in this study indicate that the water mobility in the gel formed at pH 9 could be slower than that in the gel formed at pH 7, and as a result, the leaching rate at pH 9 is slower than that at pH 7. [ABSTRACT FROM AUTHOR]

Aluminosugilite (IMA2018-142), ideal formula KNa2Al2Li3Si12O30, is a new mineral that was found in the interstices in manganiferous metacherts from the Cerchiara mine, Liguria, Italy. Aluminosugilite is an Al analogue of sugilite belonging to the milarite group. It occurs as aggregates of small prismatic and/or granular crystals up to 1mm in length, and it is pinkish-purple with a pale purple to white streak and a vitreous lustre. It has a Mohs hardness of 6-6.5. Its cleavage is indistinct, poor on (0001). Measured and calculated densities are Dmeas = 2.71-2.72 g cm-3 and Dcalc = 2.73 g cm-3, respectively. Aluminosugilite is optically uniaxial (-), with ω = 1:577-1.586 and ε = 1.575-1.585, with a weak pleochroism. The magnetic susceptibility is lower than that for sugilite. Aluminosugilite is insoluble in HCl, HNO3 and H2SO4, like sugilite. The empirical formula of aluminosugilite calculated on the basis of O = 30 from the result obtained by electron microprobe analysis and laser-induced breakdown spectroscopy is K0.99Na1.99Al1.38Mn0.313+Fe0.243+Ti0.05Mg0.01)Σ1.99Li3.06Si11.99O30. Structure refinement converged to R1 = 2:17 %. Its space group is hexagonal P6=mcc, with unit-cell parameters α = 9.9830.4/ Å, c = 13.9667.5/Å and V - 1205.45.7/ų. Based on the refined site occupancies, the ideal structural formula of aluminosugilite is CKBNa2A Al2T2Li3T1 Si12O30. The variation of the A--O3 distance is governed by the cationic substitution at the A site. The a and c dimensions of aluminosugilite are shorter than those of sugilite due to Al substitution for Fe3+ at the A site. [ABSTRACT FROM AUTHOR]

Graphical abstract Lactose fatty acid ester was synthesized using commercially available aluminosilicate zeolite as Lewis acid catalyst in different organic solvents. Reactions were done at 55 °C using pure or raw lactose with lauric acid to synthesize lactose monolaurate as biosurfactant without using lipase. Highlights • A commercial zeolite was used as a catalyst for esterification of lactose with lauric acid. • Pure and raw lactose derived from whey were used in esterification. • Products were easily purified using a solvent extraction method. • Products showed low surface and interfacial tensions compared to industrial surfactants. Abstract Sugar-based biosurfactants are safer and healthier alternatives to synthetic surfactants especially for use in the food industry. In this work, biosurfactants were synthesized via the esterification of lactose with lauric acid in different organic solvents without using lipase or other enzymes. Commercial aluminosilicate zeolite was used as a catalyst. Conversions of up to 92% were obtained for pure lactose and 38% for raw lactose from whey. Surface-active properties including surface tension, interfacial tension, and contact angle were measured. All samples showed surface tensions lower than sodium dodecyl sulfate, SDS (19.59–36.57 mN/m compared to 38.8 mN/m for SDS) and interfacial tensions comparable with it (9.47–12.18 mN/m compared to 4.77 mN/m for SDS). Results showed that aluminosilicate zeolites can be used for the synthesis of lactose esters, which have potential applications as biosurfactants for the food industry featuring low surface and interfacial tensions. [ABSTRACT FROM AUTHOR]

Abstract: An economical and green way was attempted for the synthesis of SSZ-13 catalysts by recycling waste mother liquids without adding organic template in the initial gel. The synthesized samples were characterized by XRD, BET, SEM, and NH3-TPD. The results showed that the recycling of mother liquids did not change the crystal structure, textural properties and acidity of SSZ-13, all of the samples show similar crystallinity, surface areas (550-580 m2/g), micropore volumes (0.27-0.29 cm3/g), particle sizes (10-11 µm) and Brønsted acid sites. After three recycles of mother liquids, the synthesized SSZ-13 catalyst exhibited superior ethylene plus propylene selectivity (88.7%) and catalyst lifetime (490 min) as compared to the initial SSZ-13 catalyst.Graphical Abstract: [ABSTRACT FROM AUTHOR]

Commercial aluminosilicate proppant particles have been coated with Ca-Si oxides, with the aim to provide an in-situ increase in the angularity (decrease in Krumbein roundness value) to facilitate their immobilization. Ca-Si oxide systems have been synthesized via sol-gel, cured, and sintered at 1200 °C using (a) CaCO 3 , (b) CaCO 3 + orthosilicic acid (Si(OH) 4 , SA), and (c) CaCO 3 + fused silica (SiO 2 , FS). When the proppant is cured in the presence of CaCO 3 and silicic acid the coatings undergo a significant compositional change, while sintering results in the conversion of the cured samples to ceramic agglomerates with the desired “popcorn” shapes. The best results are obtained in the presence of Si reagents, and hydration of these sintered proppants allows for a distinct increase in the angularity, which is the desired transformation to allow the proppant to be locked-in-place once located in the reservoir. The samples have been characterized at each stages of preparation by scanning electron microscopy (SEM) with associated energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and infrared (IR) spectroscopy. [ABSTRACT FROM AUTHOR]

Dynamic mechanical behavior of vertically and horizontally built AlSi10Mg_200C alloy, manufactured by SLM technique was investigated at high strain rates ranging from 150 s −1 to 1600 s −1 using Split Hopkinson Pressure Bar. Texture of the deformed samples was measured using X-ray diffraction technique. The yield strength, peak flow stress, and ductility increased in all samples with increase of strain rate. It was concluded that deformation at high strain rates had no effect on the texture components of vertical samples. However, texture transition was observed in horizontal samples, in which strong Goss and Cube components were developed at strain rate of 1600 s −1 . The texture transition and dynamic mechanical behavior of the samples were briefly discussed. [ABSTRACT FROM AUTHOR]

The present study concerns the preparation, characterization and testing of an inorganic ion exchanger Aluminum Silicate Modified Magnesia (ASMM). The ASMM composite was prepared using sol-gel technique and characterized by XRD, XRF, FTIR, TGA, DTA, SEM and surface area analysis. The capability of the prepared composite for the removal of ( Cs + , Co 2 + and Eu 3 + ) from aqueous solution was evaluated. Sorption studies were carried out taking into account important parameters such as (pH, initial concentration, contact time and temperature). Kinetic and isotherm models were applied to the prepared composite, kinetic data is well fitted with pseudo-second order kinetic model, Dubinin-Radushkevich isotherm model indicates that sorption was controlled by chemisorption process. The removal efficiency found to be 80% for Cs + , 90% for Co 2 + and 95% for Eu 3 + . [ABSTRACT FROM AUTHOR]

Garnets are naturally occurring minerals with the general formula XYZO having various applications. In the present study, the structural and physical properties of a garnet mineral obtained from Indian Rare Earth Ltd., Manavalakurichi, Tamil Nadu, India were comprehensively investigated. The compositional analysis using electron probe micro analysis (EPMA) revealed that the mineral belongs to almandine-pyrope solid solution (AlPy) with the chemical formula (FeMgMnCa) (FeAl) SiO. Rietveld refinement of the x-ray diffraction pattern confirms that the space group is $$ Ia{ - }\overline{3} d $$ with refined cubic lattice parameter a = 11.550(4) Å. The refined occupancy values of multiple cations in the dodecahedral and octahedral sites are in agreement with the EPMA data. Fourier transform infrared and FT Raman spectra show bands corresponding to almandine-pyrope solid solution. Peak splitting of IR and Raman bands confirms presence of multiple cations in the dodecahedral site. Thermogravimetric/differential thermal analysis shows that the mineral is stable up to 600°C in spite of the presence of Fe ions. Low temperature magnetic susceptibility data is in agreement with the amount of Fe ions present in the mineral. The dielectric constant of the mineral varied from 6 to 16.5 when sintered at temperatures ranging from 600°C to 1250°C. [ABSTRACT FROM AUTHOR]

This study investigates the pore structure and shrinkage behavior of metakaolin-based geopolymer pastes and mortars containing 0–30% fly ash. Fly ash substitution decreases average reactivity of the solid precursors, resulting in a lower reaction rate and accompanying longer reaction time. Composition of the sodium aluminosilicate (N-A-S-H) gel formed in the geopolymers has been changed, and the continued reaction after hardening of the pastes generates a more compact binding gel phase with lower Al/Si ratio. Refinement of the pore structure entails a higher capillary tension developed in the binders to increase the autogenous shrinkage, but also restricts the water evaporation from the pore networks, resulting in a decreased drying shrinkage. The geopolymer mortars provide higher compressive strength and lower total shrinkage when compared with the pastes. [ABSTRACT FROM AUTHOR]

Two binary geopolymers were prepared from the mixture of low-calcium bayer red mud and kaolinite-based coal gangue. The geopolymers were synthesized using two affordable and feasible methods mainly differed in preactivation and curing processes. The influence of the mix ratio of raw material and alkali activator on the compressive strength properties of two series geopolymers was investigated, and the optimal specimens of which were then determined. Furthermore, a comparative research on the mineral composition, crystal structure and microstructure of the superior geopolymers was performed through XRD, TG-DTA, and SEM-EDXS. Results revealed that GR8G2 was the optimum sample for the series geopolymer I and CR9G1 for geopolymer II. The compressive strength of all samples ranges from 15.05 to 30.25 MPa, the geopolymer synthesized from mechanical grinding preactivation displayed better developed strength. Mineral composition and microstructure studies indicated that both the final products are consist of amorphous silica-alumina-based geopolymer gels and some impurity fillers. This study showed that the two geopolymer synthesis methods for red mud and coal gangue were feasible, and the geopolymers may be applied as a new building material. Further studies are necessary to determine the optimal application parameters. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the ability of a calcium-fluoroaluminosilicate glass-based desensitizer (Nanoseal) to protect against root demineralization in vitro. Nanoseal was applied to human root dentin, which was immersed in acidic buffer for 72 h, or exposed to pH cycling by immersing in distilled water or mineralizing solution for 24 h intermediately during 48 h-acid attack. Demineralization was evaluated by μ-CT, and mineral loss (ML) and lesion depth (LD) were determined from mineral density profiles. ML and LD in all treatment groups were significantly smaller compared with control. The Nanoseal-treated group with pH cycling using mineralizing solution had the lowest ML and LD. Analysis using an EPMA demonstrated calcium and phosphorous were incorporated into the superficial layer of specimens in the Nanoseal-treated groups, suggesting Nanoseal modified the dentin surface, making it resistant to demineralization. Application of Nanoseal is an effective method for protecting root from demineralization. [ABSTRACT FROM AUTHOR]

We design and fabricate a silica optical fiber doped with yttrium aluminosilicate (YAS, Y 2 O 3 –Al 2 O 3 –SiO 2 ) nanoparticles in the core. The optical fiber is drawn directly from a silica tube with YAG (Y 3 Al 5 O 12 ) ceramics and silica powders (the molar ratio 1:18) in the core at the temperature of ∼1950 °C. The YAS nanoparticles are formed during the optical fiber drawing process. Supercontinuum (SC) generation in the optical fiber is investigated at different pump wavelength. At the pump wavelength of ∼1750 nm which is in the deep anomalous dispersion region, SC spectrum evolution is mainly due to multiple solitons and dispersive waves (DWs), and three pairs of multiple optical solitons and DWs are observed. When the pump wavelength shifts to ∼1500 nm which is close to the zero-dispersion wavelength (ZDW), flattened SC spectrum with ±7 dB uniformity is obtained at the wavelength region of ∼990–1980 nm, and only one obvious soliton and DW are observed. At the pump wavelength of ∼1100 nm, a narrow SC spectrum from ∼1020 to 1180 nm is obtained in the normal dispersion region due to self-phase modulation (SPM) effect. [ABSTRACT FROM AUTHOR]

Eu2+- as well as Ce3+-doped Ba[Li2(Al2Si2)N6] and its related Mg-substitutedcompounds Ba[(Mg2–xLix) (Al4–xSix)N6]:Eu2+(x= 0–2) with x= 1.6, 1.8 havebeen synthesized by metathesis reactions in tantalum ampules. Crystalstructures were solved and refined from single-crystal X-ray diffractiondata. All three compounds crystallize in tetragonal space group P4/ncc(no. 130) (Z=4, Ba[Li2(Al2Si2)N6]:Eu2+: a= 7.8282(4), c= 9.9557(5)Å, R1 = 0.0144, wR2 = 0.0366).Their crystal structures, exhibiting the novel framework topology whj, consist of a highly condensed anionic tetrahedra networkof disordered (Li/Mg)N4and (Al/Si)N4unitsconnected to each other by common edges and corners. The degree ofcondensation (i.e., atomic ratio (Al,Li,Mg,Si):N) is κ = 1.The Ba2+-position is coordinated eight-fold by N3–in form of a truncated square pyramid. Upon doping with Eu2+, narrow-band emission in the green to yellow spectral range is observed(λem= 532–562 nm, fwhm ≈ 1962 cm–1). Ce3+-doped crystals of Ba[Li2(Al2Si2)N6] show blue emission (λem= 468; 507 nm). According to the tunability of the narrow-bandgreen emission, application in LED-backlight liquid crystal displaysappears promising. [ABSTRACT FROM AUTHOR]

BACKGROUND In the near future, fossil fuel will have limitations in terms of availability and also great concerns over its environmental impact. New routes and related technologies based on renewable feedstocks can overcome most of these problems associated with fossil fuel. Among current biodiesel sources, ethyl levulinate ( EL) biodiesel obtained from catalytic esterification of renewable levulinic acid ( LA) with ethanol has received a great deal of attention. The use of desilicated H- ZSM-5 ( DH-ZSM-5) as heterogeneous acid catalyst for EL biodiesel production in a closed system (under autogeneous pressure) was studied. RESULTS The effect of reaction parameters such as ethanol to LA molar ratio (4:1 to 10:1), catalyst to LA ratio (0.10-0.25), speed of agitation (100-400 rpm), particle size (53-355 µm), reaction temperature (363-403 K) and reaction time (7 h) was investigated to maximize LA conversion. CONCLUSION Levulinic acid conversion reached 95% over DH-ZSM-5 and the catalyst was reusable for up to six cycles. This LA conversion and the catalyst reusability values are higher than others reported in the literature. A pseudo-homogeneous (P-H) kinetic model indicated that reaction rate constants increased with increasing molar ratio, catalyst to LA ratio and reaction temperature. The activation energy decreased from 73.14 to 21.08 kJ mol-1 when increasing the catalyst to LA ratio from 0.10 to 0.25, which implies a kinetically controlled reaction. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The article focuses on the effect of chemical stability of glass seal interfaces in intermediate temperature solid oxide fuel cells (SOFCs). It informs that researchers evaluated the chemical compatibility of a barium calcium-aluminosilicate (BCAS) based glass-ceramic with different resistant high temperature alloys. It also mentions that the sealing glass has to be chemically compatible with positive electrode-electrolyte-negative electrode (PEN).