Search results for "Chemical engineering"

Liquid–liquid equilibria of the systems isobutyl acetate+isobutyl alcohol+water and isobutyl acetate+isobutyl alcohol+glycerol at different temperatu…

2008

Abstract In this work, experimental liquid–liquid equilibria (LLE) data of the isobutyl acetate + isobutyl alcohol + water and isobutyl acetate + isobutyl alcohol + glycerol systems are presented. The LLE of both systems have been measured at 283.15 and 323.15 K. The NRTL and UNIQUAC models were applied to both ternary systems. The interaction parameters obtained from both models successfully correlated the equilibrium compositions. The experimental tie lines were compared to the values predicted by the UNIFAC method. Moreover, the solvent capabilities of water and glycerol were compared.

Supercritical Fluid Extraction and Supercritical Fluid Chromatography of Vitamin E in Pharmaceutical Preparations

1999

Liquid chromatography detectors second, completely revised edition by R. P. W. Scott Perkin-Elmer Corporation, Instrument Group, Main Avenue, Norwalk…

1986

Glucose oxidase as a biocatalytic enzyme-based bio-fuel cell using Nafion membrane limiting crossover

2013

A novel combination for an Enzyme-based Biofuel cell included a Nafion membrane as an ion transporter that maintained a working cell charge and inhibited membrane degradation. The prototype cell chamber used oxygen (O2) in the cathode cell and glucose in the anode. The Nafion membrane stability studied here was evidently in the region of 0% loss of conductivity as the charge was constant and increased after the addition of glucose. The prototype cell chamber used NaCl in the cathode cell and glucose oxidase (GOx) in the anodic chamber was successfully studied for membrane stability showed in this study no evidence of poisoning from membrane leakage in a controlled pH environment. There was …

Fully aerobic bioscrubber for the desulfurization of H2S-rich biogas

2019

Abstract A fully aerobic bioscrubber for the desulfurization of H2S-rich biogas was developed in the present study by coupling an absorption column and a bubble column bioreactor. The bioscrubber treated H2S loading rates of 37, 59, and 100 g S mliquid−3 h−1 at gas residence times of 6.6, 4.1 and 2.4 min in the absorption column, respectively. Stable H2S removal efficiencies above 80% were recorded at all the conditions tested. The bioscrubber was robust towards short- and long-term operation shutdowns (5 and 18 days), the H2S removal performance being recovered after few hours. The aerated bubble column bioreactor was operated at slightly alkaline conditions (pH 8 ± 0.5), which prevented H…

Inducing mixing of water-in water BSA/dextran emulsion by a strong polyelectrolyte

2015

Abstract We examine whether a small amount of strong polyelectrolyte (dextran sulfate sodium salt/DSS/) can induce mixing in water-in-water bovine serum albumin/dextran (BSA/DEX) emulsion and how intermacromolecular interactions affect its the rheological properties. Addition of DSS to water-in-water emulsion at pH 5.4 leads to its mixing at the DSS/BSA weight ratio, ( q ( DSS / BSA ) ) ≥ 0.07 , a noticeable increase in viscosity and storage modulus (G′). Mixing is reversible: increasing the ionic strength leads to phase separation in the water/BSA/DEX/DSS system. The increase in viscoelasticity results from the interaction of DSS with both macromolecular compounds of the emulsion. We assum…

Overlapped moving windows followed by principal component analysis to extract information from chromatograms and application to classification analys…

2015

Variable generation from chromatograms is conveniently accomplished using unsupervised rather than manual techniques. With unsupervised techniques, there is no need for selecting a few peaks for manual integration and valuable information is quickly and efficiently collected. The generation of variables can be performed by using either peak searching or moving window (MW) strategies. With a MW approach, the peaks are ignored and many variables, only part of them carrying information, are generated. Thus, variable generation by MWs should be followed by data compression to generate the variables to be further used for classification or quantitation purposes. In this work, unsupervised proces…

Structural and dynamical investigation of gelation containing water-in-oil microemulsions

1996

The gelatin (Bloom 300)/water/AOT/n-heptane system has been investigated at fixed water/AOT molar ratioR (R=31.1) as a function of the gelatin content. Several experimental techniques (densitometry, refractometry, conductometry, rheology, dielectrometry, ultrasonics, hypersonics) have been used to investigate the role played by the gelatin molecule in the observed sol-gel transition above a critical gelatin content. The results appear consistent with the hypothesis of a rigid network of gelatin-water rods coated by surfactant molecules coexisting with gelatin-free AOT reversed micelles at the gelation point.

Electronic properties and corrosion resistance of passive films on austenitic and duplex stainless steels

2018

Abstract Passive films were grown at constant potential in acidic (pH∼2) and alkaline (pH∼13) solutions on chromium, AISI 304L, AISI 316L and Duplex stainless steels. Passive films on chromium grow following a high field mechanism considering the presence of dissolution phenomena. According to the photoelectrochemical characterization, passive films on Cr have a bandgap of 3.4 eV when formed in acidic solution, and of 2.4 eV when formed in alkaline solution due to the formation of Cr(OH)3. These films result to be poorly stable against anodic dissolution due to a very anodic flat band potential. Conversely, impedance and photoelectrochemical measurements proved that passive films on stainle…

Production of spray-dried proanthocyanidin-rich cinnamon (Cinnamomum zeylanicum) extract as a potential functional ingredient: Improvement of stabili…

2018

International audience; Cinnamon proanthocyanidins present important biological properties. However, these molecules are unstable and possess an astringent taste, which can make their ingestion difficult. In this context, entrapment by spray-drying technology may be used to produce a concentrated extract with improved stability and reduced astringency. Thus, this work aimed to prepare spray-dried microparticles loaded with a proanthocyanidin-rich cinnamon (Cinnamomum zeylanicum) extract (PRCE), immobilized in a maltodextrin matrix. Freeze-dried samples of the extract (without the carrier) were also prepared for comparison. The particles were characterized for moisture content, water activit…