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In the anodic ethanol oxidation reaction (EOR) for direct ethanol fuel cells, the coverage of hydroxide (OHads) is a major adsorbent competing with C–C bond cleavage, which is necessary for complete ethanol oxidation (C1-pathway) and durability. Beyond utilizing a less-alkaline electrolyte that causes ohmic losses, an alternative strategy to optimize OHadscoverage is to intentionally exploit local pH changes near the electrocatalyst surface that are governed by a combination of released H+during EOR and OH–mass transport from the bulk solution. Here, we manipulate the local pH swing by fine-tuning the electrode porosity with Pt1–xRhxhollow sphere electrocatalysts based on particle size (250 and 350 nm) and mass loading. With the smaller size of 250 nm, Pt0.5Rh0.5(∼50 μg cm–2) shows a high activity of 1629 A gPtRh–1(2488 A gPt–1) in a 0.5 M KOH-containing electrolyte, which is ∼50% higher than the most active binary catalysts to date. Moreover, a higher C1-pathway Faradaic efficiency (FE) of 38.3% and 80% longer durability are achieved with a 2-fold increase in mass loading. In the more porous electrodes, a local acidic environment created by hindered OH–mass transport better optimizes OHadscoverage, providing more active sites for the desired C1-pathway and a continuous EOR.

The binder jetting method wherein a liquid adhesive is sprayed and built up on a powder material, such as sand, is relatively fast among 3D printing technologies, and it has a wide range of applications due to the flexibility to use various materials in powdered form. In this study, to secure jetting stability when synthesizing a silicate (SiO2–Na2O)-based inorganic binder for binder jetting, the optimum physical properties of the inorganic binder were confirmed by controlling the viscosity and surface tension. In addition, the strength of the printed mold body, which changes according to the properties of the powder used for printing, was confirmed. As a result, the inorganic binder for 3D printing had a surface tension between 45.9 and 47.1 mN/m, and the binder with a Zvalue between 9.45 and 9.98 formed stable droplets. In addition, the more hydrophilic the surface of the powder used for 3D printing, the higher the affinity between the surface and the inorganic binder, which increases the wettability, thus enhancing the printing quality. However, we confirmed the final strength of the product decreased because the binder bridge was short owing to the low contact angle.

Sand cores in sand casting and permanent molds are manufactured by combining sand and binders. In this process, high-temperature molten metals decompose binders into gases, causing pore defects during casting since the gases cannot escape completely. Therefore, eco-friendly inorganic binders with reduced pore defects have gained attention. A quantitative analysis of inorganic binder gas generation was conducted in this study using a thermogravimetry-mass spectrometry (TG–MS) coupling system, wherein the specimens solidified a liquid inorganic binder only instead of a mold block mixed of sand and binder. At 1000 °C, the inorganic binder lost approximately 33.2% weight while releasing water vapor and CO2. The decomposition temperature was between 150 and 300 °C for water vapor, and between 450 and 550 °C for CO2. In the Ar gas atmosphere, the weight of gaseous emissions was the same as the TG weight loss; however, in the air, the weight of gaseous emissions was approximately 10% higher than the TG weight loss. Using these results, gas defects in a product can be predicted by calculating the used weight of binder during molding and tracking gases diffusion during casting.

A simple, cost‐effective, and greener HPLC method was investigated to determine 14 β‐lactams. To achieve this, various strategies were implemented such as the use of an aqueous mobile phase, ionic liquids, or an alternative organic solvent. Preliminary experiments were conducted using “one‐factor‐at‐a‐time” to identify the significant factors affecting chromatographic performance. The experimental design (central composite design) was then applied to thoroughly examine the effects of the key factors and exploit them to achieve optimal HPLC condition. The developed method was less hazardous and improved the retention and peak shape, compared with other conventional methods. The optimized assay condition was validated according to the ICH guidelines and effectively applied for the quantification of some β‐lactams in various formulations. These results imply that this novel HPLC method can be employed for routine analyses of some β‐lactams in pure drug and commercial formulations. Combination of Green analytical chemistry and Experimental design in the determination of β‐lactams.

Silicon (Si) is considered to be one of the most promising anode candidates for next-generation lithium-ion batteries because of its high theoretical specific capacity and low discharge potential. However, its poor cyclability, caused by tremendous volume change during cycling, prevents commercial use of the Si anode. Herein, we demonstrate a high-performance Si anode produced via covalent bond formation between a commercially available Si nanopowder and a linear polymeric binder through an esterification reaction. For efficient ester bonding, polyacrylic acid, composed of −COOH groups, is selected as the binder, Si is treated with piranha solution to produce abundant −OH groups on its surface, and sodium hypophosphite is employed as a catalyst. The as-fabricated electrode exhibits excellent high rate capability and long cycle stability, delivering a high capacity of 1500 mA h g–1after 500 cycles at a high current density of 1000 mA g–1by effectively restraining the susceptible sliding of the binder, stabilizing the solid electrolyte interface layer, preventing the electrode delamination, and suppressing the Si aggregation. Furthermore, a full cell is fabricated with as-fabricated Si as an anode and commercially available LiNi0.6Mn0.2Co0.2O2as a cathode, and its electrochemical properties are investigated for the possibility of practical use.

Metal foundries use high quality sand in the casting process and produce vast amounts of used foundry sand (UFS). Thus, in order to make the best use of foundry sand in the casting process, it is essential to demonstrate an appropriate recycling method and verify the influence of regenerated foundry sand (RFS) on the mechanical properties of core. In this study, physical and chemical characterizations were conducted on the RFS and the physical properties of cores containing different proportions of RFS were investigated with respect to the flexural strength. The UFS produced in controlled conditions was recycled by a wet type method and the regular foundry sand was replaced with varying proportions of RFS by weight (0, 20, 40 and 60 wt. %). Although the gradation of RFS was analogous with the regular foundry sand, the flexural strength test indicated that the sand mixture with 20 wt. % replacement of regular foundry sand was appropriate for core making without a drastic decrease of flexural strength. The flexural strength decreased with the increase of RFS contents at replacement proportion more than 20 wt. %.

Despite growing interest in calcium (Ca)-based batteries for sustainable energy storage, there are a limited number of electrolytes that enable the reversible plating/stripping of Ca metal. Consequently, an understanding of the interplay between electrolyte formulation, solid electrolyte interphase (SEI) composition, and electrochemical performance lags behind that of other alkali and alkaline-earth batteries. In this context, this study examines how plating/stripping behavior and SEI formation are modulated by differential changes in solvent composition and the resulting Ca2+–anion speciation in borohydride electrolytes comprising ether solvent blends. Starting with the baseline electrolyte 1 M Ca(BH4)2in tetrahydrofuran (THF), THF was systematically replaced by 1,2-dimethoxyethane (G1) or bis(2-methoxyethyl) ether (G2) over a range of Gx:Ca2+molar ratios (0–4:1 G1:Ca2+or 0–3:1 G2:Ca2+). Replacement of THF by glymes increased the plating overpotential and decreased the Coulombic efficiency of Ca plating/stripping, and a marked decrease in electrochemical activity occurred at a composition threshold for each glyme. Comparison between the X-ray photoelectron spectra of electrolyte-soaked Ca and electrodeposited Ca revealed a relative increase in organic C–O species and a decrease in borate species in the electrochemically-formed SEI with increased glyme proportion in the electrolyte. NMR and Raman spectroscopy connected SEI composition to differential Ca2+coordination, as glymes displace THF from the Ca2+coordination environment, weaken Ca2+–BH4–interactions, and prompt BH4–reorganization. Overall, BH4–-facilitated solvent decomposition governs Ca electrochemistry in these systems, as coordinated THF promotes beneficial borate formation but coordinated glymes limit such phases, leading to Ca2+-blocking phases in the SEI. These findings delineate future directions to modulate Ca(BH4)2coordination toward improving electrolyte reversibility by considering the O-donating ability of the coordinating solvent.

It has been widely suggested in literature that a lithium fluoride (LiF)-rich solid electrolyte interphase (SEI) affects Coulombic efficiency (CE) of the Li metal anode used with liquid electrolytes. Yet, the influence of LiF on Li metal deposition has been challenging to examine. Herein, we developed a method to synthesize LiF nanoscale particles with tunable sizes (30–300 nm) on Cu electrodes by electrochemical reduction of fluorinated gases under controlled discharge rates and capacities. The impact of LiF nanoparticles on overpotential and morphology of Li deposition was further studied in a conventional carbonate electrolyte. By cyclic voltammetry, Li plating overpotentials exhibit a clear correlation with the total surface area of LiF particles. Additionally, Li metal deposits (10 μAh cm−2) nucleated under galvanostatic conditions (0.5 mA cm−2) on Cu/LiF showed increasing feature sizes with a lower average LiF particle size and higher coverage of LiF. However, no significant improvement in CE was observed for LiF-coated Cu. Our findings provide evidence that a particle-based mode of SEI fluorination can influence early-stage Li nucleation to a modest degree, and this effect is maximized when LiF is uniformly and densely distributed. However, sparser and larger LiF have vanishing or even detrimental effect on cycling performance.

The purpose of this study was to determine whether the Laurus nobilischloroform fraction (LNCF) protects against cerebral ischemia neuronal damage. Human neuroblastoma SH-SY5Y cells and brain slices from rats were subjected to oxygen and glucose deprivation (OGD), followed by reoxgenation with and without LNCF. The viabilities of SH-SY5Y cells and brain slices from the rats were 58.5±4.9% and 79.7±5.9% in the group subjected to OGD, and 80.4±0.4% and 97.2±1.9% at 4 μg/ml of LNCF, respectively. LNCF also significantly inhibited death-associated protein kinase (DAPK) dephosphorylation. Pretreatment with LNCF at 4 mg/kg significantly decreased infarct size by 79% of vehicle control in the middle cerebral artery occlusion (MCAO) in vivomodel. LNCF is a neuroprotective drug candidate against cerebral ischemia neuronal damage.

A coupled achiral–chiral high performance liquid chromatographic method was developed and fully validated for the determination of bevantolol enantiomers, (−)‐(S)‐bevantolol and (+)‐(R)‐bevantolol, in human plasma. Plasma samples were prepared by solid phase extraction with Sep‐Pak Plus C18 cartridges followed by HPLC. Bevantolol enantiomers and (+)‐(R)‐Propranolol as internal standard (IS) were preseparated from interfering components in plasma on a Phenomenex silica column and bevantolol enantiomers and IS were resolved and determined on a Chiralcel OJ‐H chiral stationary phase. The two columns were connected by a switching valve equipped with silica precolumn. The Precolumn was used to concentrate bevantolol in the eluent from the achiral column before back flushing onto chiral phase. A detailed validation of the method was performed accordingly to FDA guidelines. For each enantiomer the assay was linear between 20 and 1600 ng/ml. The quantification limits of both bevantolol enantiomers were 20 ng/ml. The intraday variation was between 1.07 and 12.64% in relation to the measured concentration and the interday variation was 0.91 and 11.79%. The method has been applied to the determination of (−)‐(S)‐ and (+)‐(R)‐bevantolol in plasma from healthy volunteers dosed with racemic bevantolol hydrochloride. hydrochloride. Chirality, 2007. © 2007 Wiley‐Liss, Inc.

Thirteen phenolic compounds from Aloe barbadensis (syn. A. vera)and A. arborescenswere analysed by high performance liquid chromatography, using a reverse phase column eluted with a methanol: water gradient, and detected by UV at 293 nm. Aloesin, 8‐C‐glucosyl‐7‐O‐methyl‐(S)‐aloesol, neoaloesin A, 8‐O‐methyl‐7‐hydroxyaloin A and B, 10‐hydroxyaloin A, isoaloeresin D, aloin A and B, aloeresin E and aloe‐emodin from A. barbadensis:and aloenin, aloenin B, 10‐hydroxyaloin A, aloin A and B, and aloe‐emodin from A. arborescens,were identified and quantified. The seasonal variation of two Aloespecies was also examined by this method. © 1998 John Wiley & Sons, Ltd.

The changes of electrical resistivity of Y2O3-doped ZrO2s with microstructural modifications were investigated. Using ZrO2powders containing 3 mol% Y2O3and 8 mol% Y2O3, seven kinds of microstructures were designed by various preparing techniques; two single phase specimens and five mixed phase specimens. The contributions of structural components, i.e., bulk and boundaries, and apparent total resistivities were identified by impedance analysis method. At low temperature region, grain and/or phase boundaries play an important role in electrical resistivity.

Thirteen phenolic compounds from Aloe barbadensis (syn. A. vera) and A. arborescens were analysed by high performance liquid chromatography, using a reverse phase column eluted with a methanol: water gradient, and detected by UV at 293 nm. Aloesin, 8-C-glucosyl-7-O-methyl-(S)-aloesol, neoaloesin A, 8-O-methyl-7-hydroxyaloin A and B, 10-hydroxyaloin A, isoaloeresin D, aloin A and B, aloeresin E and aloe-emodin from A. barbadensis: and aloenin, aloenin B, 10-hydroxyaloin A, aloin A and B, and aloe-emodin from A. arborescens, were identified and quantified. The seasonal variation of two Aloe species was also examined by this method. © 1998 John Wiley & Sons, Ltd.