Nitrogen solubility in CaO-CaF2-SiO2 melts

The preceding paper^[5] demonstrated that nitrogen dissolves in silicate melts either as a free ion or complex anion, being incorporated into silicate networks. In the present study, the influence of CaF₂ addition to CaO-SiO₂ melts on the nitrogen solubility was investigated along the liquidus at 1573 K and within the liquidus at 1723 K at constant CaF₂ levels. In the latter case, as the SiO₂ content increases from CaO saturation, the total nitrogen content decreases to reach the minimum and then starts to increase up to the SiO₂ saturation. This is in accord with the abovementioned mechanism of nitrogen dissolution, which is supported by the changing behavior of free and incorporated nitrogen contents with the slag composition. The role of CaF₂ is complicated through the formation of fluorosilicates. The CaF₂ seems not to function simply as a diluent but to enhance the dissolution of nitrogen by releasing oxygen from silicate networks, promoting the formation of free nitride ions. Formerly Graduate Student, Department of Metallurgy, The University of Tokyo.     

Automatic searching and evaluation of priority and emerging contaminants in wastewater and river water by stir bar sorptive extraction followed by comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry

A new analytical method based on stir bar sorptive extraction (SBSE), followed by comprehensive two-dimensional gas chromatography (GCxGC-TOF-MS), has been developed for the automatic searching and evaluation of nonpolar or semipolar contaminants in wastewater and river water. The target compounds selected were 13 personal care products (PCPs), 15 polycyclic aromatic hydrocarbons (PAHs) and 27 pesticides. Excellent results have been obtained in terms of separation efficiency and also in terms of compound identification. Exceptional method detection limits were achieved applying the optimized method, at or below 1 ng/L for most of the compounds in real samples. The reliable confirmation of analyte identity was possible at this low concentration level, even for typically troublesome compounds such as the PAHs. The other validation parameters were good. In addition to obtaining analytical information such as identification and quantification of target analytes, it is also possible to screen for nontarget compounds or unknowns. New contaminants have been identified in the wastewater effluents and river water samples, such as cholesterol and its degradation products, pharmaceuticals, industrial products, other pesticides, and PCPs. The multidimensional information generated by the instrument can also be used by the researchers for contrasting samples and identifying, much more easily, the major differences between samples. We have used this feature to propose studies of comparison between the fingerprinting of different water samples, such as the contamination variation along a river affected by the discharge of urban wastewaters and also the contamination variation over a period of time in the effluent. Results show that the most frequently detected contaminants (and the contaminants detected at higher concentrations) were the PCPs. The musk fragrances galaxolide and tonalid were the most concentrated compounds in the samples. The pesticides and PAHs were present at much lower concentration than PCPs.     

Degradation of pharmaceutical beta-blockers by electrochemical advanced oxidation processes using a flow plant with a solar compound parabolic collector

The degradation of the beta-blockers atenolol, metoprolol tartrate and propranolol hydrochloride was studied by electro-Fenton (EF) and solar photoelectro-Fenton (SPEF). Solutions of 10 L of 100 mg L⁻¹ of total organic carbon of each drug in 0.1 M Na₂SO₄ with 0.5 mM Fe²⁺ of pH 3.0 were treated in a recirculation flow plant with an electrochemical reactor coupled with a solar compound parabolic collector. Single Pt/carbon felt (CF) and boron-doped diamond (BDD)/air-diffusion electrode (ADE) cells and combined Pt/ADE-Pt/CF and BDD/ADE-Pt/CF cells were used. SPEF treatments were more potent with the latter cell, yielding 95-97% mineralization with 100% of maximum current efficiency and energy consumptions of about 0.250 kWh g TOC⁻¹. However, the Pt/ADE-Pt/CF cell gave much lower energy consumptions of about 0.080 kWh g TOC⁻¹ with slightly lower mineralization of 88-93%, then being more useful for its possible application at industrial level. The EF method led to a poorer mineralization and was more potent using the combined cells by the additional production of hydroxyl radicals (^•OH) from Fenton’s reaction from the fast Fe²⁺ regeneration at the CF cathode. Organics were also more rapidly destroyed at BDD than at Pt anode. The decay kinetics of beta-blockers always followed a pseudo first-order reaction, although in SPEF, it was accelerated by the additional production of ^•OH from the action of UV light of solar irradiation. Aromatic intermediates were also destroyed by hydroxyl radicals. Ultimate carboxylic acids like oxalic and oxamic remained in the treated solutions by EF, but their Fe(III) complexes were photolyzed by solar irradiation in SPEF, thus explaining its higher oxidation power. NO₃⁻ was the predominant inorganic ion lost in EF, whereas the SPEF process favored the production of NH₄⁺ ion and volatile N-derivatives.     

Prediction of catalyst stability in naphtha reforming

A method to predict catalyst activity (RON) and selectivity (ηc5⁺, liquid yield) of naphtha-reforming catalysts during normal operation is described. It involves performing experiments at normal operational conditions and testing accelerated deactivation. These last experiments have a severe intermediate period at lower pressure. Carbon formation is related to time and the decrease in RON and ηc5⁺ is related to carbon at normal operation. The accelerated deactivation produces a similar coke to the one at normal conditions for an equal amount of coke. Therefore for each time at normal conditions there is a corresponding pressure in the accelerated deactivation test. Power law-equations fit the data well and combining them results in the following relations: P = at^b; Δ_NRON = cP^d; Δ_Nηc5⁺ = eP^f. The coefficients a, b, c, d, e and f depend on the catalyst and are calculated from four or six experiments (half at normal conditions and half accelerated deactivation tests); b, d and f bare negative. The value of pressure for the time at which it is desired to predict catalyst activity and selectivity is calculated from the first equation. This value when applied to the second and third equations gives the activity and selectivity, respectively, that the catalyst will have after time t.     

Polymeric Microspheres/Cells/Extracellular Matrix Constructs Produced by Auto-Assembly for Bone Modular Tissue Engineering

Modular tissue engineering (MTE) is a novel “bottom-up” approach to create engineered biological tissues from microscale repeating units. Our aim was to obtain microtissue constructs, based on polymer microspheres (MSs) populated with cells, which can be further assembled into larger tissue blocks and used in bone MTE. Poly(L-lactide-co-glycolide) MS of 165 ± 47 µm in diameter were produced by oil-in-water emulsification and treated with 0.1 M NaOH. To improve cell adhesion, MSs were coated with poly-L-lysine (PLL) or human recombinant collagen type I (COL). The presence of oxygenated functionalities and PLL/COL coating on MS was confirmed by X-ray photoelectron spectroscopy (XPS). To assess the influence of medium composition on adhesion, proliferation, and osteogenic differentiation, preosteoblast MC3T3-E1 cells were cultured on MS in minimal essential medium (MEM) and osteogenic differentiation medium (OSG). Moreover, to assess the potential osteoblast–osteoclast cross-talk phenomenon and the influence of signaling molecules released by osteoclasts on osteoblast cell culture, a medium obtained from osteoclast culture (OSC) was also used. To impel the cells to adhere and grow on the MS, anti-adhesive cell culture plates were utilized. The results show that MS coated with PLL and COL significantly favor the adhesion and growth of MC3T3-E1 cells on days 1 and 7, respectively, in all experimental conditions tested. On day 7, three-dimensional MS/cell/extracellular matrix constructs were created owing to auto-assembly. The cells grown in such constructs exhibited high activity of early osteogenic differentiation marker, namely, alkaline phosphatase. Superior cell growth on PLL- and COL-coated MS on day 14 was observed in the OSG medium. Interestingly, deposition of extracellular matrix and its mineralization was particularly enhanced on COL-coated MS in OSG medium on day 14. In our study, we developed a method of spontaneous formation of organoid-like MS-based cell/ECM constructs with a few millimeters in size. Such constructs may be regarded as building blocks in bone MTE.     

Anticipation of digital patterns

A memristive device is a novel passive device, which is essentially a resistor with memory. This device can be used for novel technical applications like neuromorphic computation. In this paper, we focus on anticipation—a capability of a system to decide how to react in an environment by predicting future states. Especially, we have designed an elementary memristive circuit for the anticipation of digital patterns, where this circuit is based on the capability of an amoeba to anticipate periodically occurring unipolar pulses. The resulting circuit has been verified by digital simulations and has been realized in hardware as well. For the practical realization, we have used an Ag‐doped TiO_2?x‐based memristive device, which has been fabricated in planar capacitor structures on a silicon wafer. The functionality of the circuit is shown by simulations and measurements. Finally, the anticipation of information is demonstrated by using images, where the robustness of this anticipatory circuit against noise and faulty intermediate information is visualized.     

Oxidative and photochemical processes for the removal of galaxolide and tonalide from wastewater

Synthetic musks have been reported in wastewaters at concentrations as high as tens of micrograms per litre. The two most significant polycyclic musk fragrance compounds are 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta(g)-2-benzopyran (HHCB, trade name galaxolide^®) and 7-acetyl-1,1,3,4,4,6-hexamethyltetrahydronaphthalene (AHTN, trade name tonalide^®). We report the result of several irradiation and advanced oxidation processes carried out on samples of the effluent of a wastewater treatment plant located in Alcalá de Henares, Madrid. Wastewater samples were pre-ozonated and spiked with 500 ng/L of tonalide or galaxolide in order to obtain final concentrations in the same order as the raw effluent. The treatments assayed were ozonation with and without the addition of hydrogen peroxide (O₃, O₃/H₂O₂), ultraviolet (254 nm low pressure mercury lamp) and xenon-arc visible light irradiation alone and in combination with ozone (UV, O₃/UV, Xe, O₃/Xe) and visible light photocatalytic oxidation using a Ce-doped titanium dioxide photocatalyst performed under continuous oxygen or ozone gas bubbling (O₂/Xe/Ce-TiO₂, O₃/Xe/Ce-TiO₂). In all cases, samples taken at different contact times up to 15 min were analyzed. An analytical method based on stir bar sorptive extraction (SBSE), followed by comprehensive two-dimensional gas chromatography (SBSE-GC × GC-TOF-MS), was used for the automatic searching and evaluation of the synthetic musks and other nonpolar or semipolar contaminants in the wastewater samples. In all cases tonalide was more easily removed than galaxolide. The best results for the latter (more than 75% removal after 5 min on stream) were obtained from ozonation (O₃) and visible light photocatalytic ozonation (O₃/Xe/Ce-TiO₂). A significant removal of both pollutants (∼60% after 15 min) was also obtained during visible light photocatalysis (O₂/Xe/Ce-TiO₂). UV radiation was able to deplete tonalide (+90%) after 15 min but only reduced the concentration of galaxolide to about half of its initial concentration. The toxicity of treated samples decreased for O₃/UV and O₃/Ce-TiO₂, but increased during irradiation processes UV, Xe and Xe/Ce-TiO₂. Ozone treatments tend to decrease toxicity up to a certain dosage, from which point the presence of toxic transformation products has adverse effects on aquatic microorganisms.     

Use of ceramic industry milling and glazing waste as an active addition in cement

The beneficial effects of pozzolans on cement manufacture have encouraged their use in that industry. Traditional natural pozzolan have become less available of late, however, due to a decline in quarrying intensity aimed at minimizing the impact on the landscape. At the same time, environmental policies pursue the reduction or elimination of spoil heaps by valorizing industrial waste and by‐products as raw materials, in keeping with the principles of the circular economy. The quest for new types of waste and by‐products with pozzolanic properties has consequently become a priority line of research. This study explored the valorization of one such by‐product, the ceramic sludge resulting from fired clay industry milling and glazing, as a component in new, more eco‐sustainable cements. The sludge was characterized physically, chemically, morphologically, and mineralogically to determine its suitability as a pozzolanic addition in cement. The findings showed that ceramic sludge consists in clustered particles ranging in size from 100 μm to 1 μm. SiO₂, Al₂O₃, and Fe₂O₃ together comprise over 70% of the total composition, while the reactive silica content is greater than the 25% required by the existing legislation. The predominant minerals are quartz, kaolinite, and muscovite, with some zircon. A study of pozzolanic reaction kinetics in the ceramic sludge/lime system revealed that over time this waste can fix lime, generating products such as calcium aluminate hydrates and C–S–H gels. The cements made with ceramic sludge proved to be standard‐compliant in terms of water demand, setting, drying shrinkage and mechanical strength.     

Bioactive efficacy of low‐density polyethylene films with natural additives

Active packaging can be defined as packaging that includes additives that help to extend the shelf life of food; among the advantages of its use is the possibility to reduce the amount of additives added to the food during processing. The aim of this study was to develop, characterize, and apply active films of low‐density polyethylene, incorporating carotenoid and yerba mate extracts as active additives. Active films were obtained by extrusion and were characterized for water vapor permeability, thickness, color, and mechanical and thermal properties. The effectiveness of the films was evaluated using butter packed in the formulated films. There was a significant reduction in thickness, and mechanical, thermal, and water vapor barrier parameters of the films compared to the control. The concentration of additives directly influenced coloration and antioxidant and antimicrobial action of the films. The formulated films provided protection against oxidative action and inhibition of microbial growth. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46461.