QuEChERS Method for the Determination of 3‑Alkyl‑2‑Methoxypyrazines in Wines by Gas Chromatography-Mass Spectrometry

A new method for determining 3-isopropyl-2-methoxypyrazine, 3-sec-butyl-2-methoxypyrazine, and 3-isobutyl-2-methoxypyrazine in wines is presented. A modified quick, easy, cheap, effective, rugged, and safe method and gas chromatography-mass spectrometry (GC-MS) were used for sample preparation and compound determination, respectively. The analytes were extracted from wine (30 mL) with 1 mL toluene, in the presence of 12 g anhydrous MgSO₄ and 3 g NaCl. Cleanup of the toluene phase was performed by a miniaturized dispersive solid-phase extraction with a combination of anhydrous CaCl₂ (25 mg), anhydrous MgSO₄ (25 mg), and primary-secondary amine (10 mg), which was effective for minimizing co-extractives and matrix effects. GC-MS parameters were also tuned up to optimize limits of detection between 4.2 and 7.1 ng L^?1. The overall recoveries (trueness) of the method ranged between 71 and 87 % for the white and red wine samples, respectively, spiked at 40 and 100 ng L^?1, with relative standard deviations below 21 %. The method was applied for the determination of target methoxypyrazines in the samples of commercial wines from Argentina.     

Prediction of Vapor‐Liquid Equilibrium inside Capillary Porous Plates

Capillary distillation is a relatively new separation process which uses capillary porous media for the separation of mixtures. It utilizes the solid‐liquid interfacial forces to alter the vapor‐liquid equilibrium (VLE) of mixtures inside the capillary porous plates. Previous studies have shown that capillary porous plates could significantly alter the VLE of binary mixtures. It was shown that the main factors affecting the alteration of VLE of binary mixtures are the polarization of the liquids and the porous plates as well as the polarization difference between the mixture components. In this study, the VLE data for the mixtures inside capillary porous plates have been predicted using the Wilson model and the theory of Abu Al‐Rub and Datta on VLE inside capillary porous media. The validity of the developed model has been assessed by comparing predicted VLE results of some binary mixtures inside capillary porous plates with experimental VLE data. The comparison showed that the model developed could predict the VLE of the studied systems accurately.     

Testing New In-Kiln Meter for Monitoring Lumber Moisture Content during Drying

The objective of this study was to test a new in-kiln sensor for monitoring lumber moisture content during industrial drying. The theoretical foundation of the technology was already known, because it is based on electrical conductivity, but the mechanism of implementation was new and required validation. For this reason, the technology was compared with two other widely used methods for assessing lumber moisture content, namely, the oven-drying and electrical capacitance methods. The tests were performed in a 120-m³ industrial kiln operated by a sawmill in the eighth region of Chile, and the results showed that the average moisture content at the end of drying was satisfactorily determined by the new in-line sensor. As predicted by theory, the sensor was not able to accurately measure moisture content above 25%, but it was still able to provide the equivalent of a drying curve for monitoring of the drying process.     

Influence of Different Additives on the Interaction of Quinolone Antibiotic Drug with Surfactant: Conductivity and Cloud Point Measurement Study

Conductometric and cloud point (CP) measurement studies have been performed to investigate the interaction of tetradecyltrimethylammonium bromide (TTAB) and Triton® X-100 (TX-100) with ciprofloxacin hydrochloride (CFH) in different solvents over the temperature range of 295.15–315.15 K. CFH is used for the treatment of various bacterial infections. The observed critical micelle concentration (CMC) values of TTAB were found to be reduced in the presence of electrolytes (Na₂SO₄/Na₃PO₄), and this reduction proceeds with the elevation of salt concentration. The order of the CMC of TTAB follows the trend: > >. The observed CMC values of TTAB were found to increase with increasing temperature and decrease with increasing concentration of CFH in aqueous medium. The values of Gibbs free energy of micellization () for the TTAB/TTAB + CFH mixture were found to be negative, implying spontaneous micellization. The estimated CP of TX-100 decreases with increasing concentration of TX-100 in aqueous medium. The CP values first decrease with increasing concentration of CFH and then increase at higher concentration of CFH almost in all cases investigated. The values of free energy of clouding were found to be positive in all cases studied implying that phase separation of TX-100 was nonspontaneous. The other thermodynamic parameters associated with the micellization of TTAB and the phase separation of TX-100 were estimated and explained.     

A new SEAIRD pandemic prediction model with clinical and epidemiological data analysis on COVID-19 outbreak

Applied Intelligence - Measuring the spread of disease during a pandemic is critically important for accurately and promptly applying various lockdown strategies, so to prevent the collapse of the...