Search results for "Turing"
showing 10 items of 2644 documents
High pressure processing of fruit juice mixture sweetened with Stevia rebaudiana Bertoni: Optimal retention of physical and nutritional quality
2013
Abstract The impact of high pressure processing (HPP) technology on physicochemical properties (color, browning index, turbidity index), bioactive compounds (ascorbic acid, total phenolic compounds, total anthocyanins, total carotenoids) and antioxidant capacity of a fruit juice mixture (papaya (32.5%, v/v), mango (10%, v/v) and orange (7.5%, v/v)) sweetened with Stevia rebaudiana Bertoni at different percentages was studied. The experimental design comprised a response surface methodology according to a central composite face-centered design. The variable ranges were 300–500 MPa (pressure), 5–15 min (time), 0–2.5% Stevia percentage. This design was used to determine the optimal high pressu…
Immobilization of vegetable tannins on tannery chrome shavings and their use for the removal of hexavalent chromium from contaminated water
2011
Abstract Chestnut (C) and mimosa (M) tannins immobilized on chrome shavings (CS) as an adsorbent have been proposed to be an efficient and economical alternative in hexavalent chromium removal from aqueous solutions. The adsorption of hexavalent chromium onto chrome shavings-tannin (CS-T) adsorbents was performed using batch equilibrium technique at 25 ± 2 °C. The effect of pH is highly important especially in the case of high concentrations of hexavalent chromium. The maximum chromium uptake was obtained at pH 4. Two hours of contact time are enough to reach equilibrium. Sorption of chromium on CS-T was found to follow a pseudo-second order kinetic model (with correlation coefficients grea…
Bimolecular reduction of 9-alkyl-3-nitrocarbazoles
2007
AbstractReduction of 9-alkyl-3-nitrocarbazoles (Ia–Ie) with lithium aluminium hydride gave corresponding 9,9′-dialkyl-3,3′-azocarbazoles (IIa–IIe) in moderate yield. By the action of zinc dust in alcohol and aqueous alkali on I or II, 5,13-dialkyldiindolo[3,2-a,d]phenazines (IIIa–IIId) were obtained. Parent compounds, viz. 3,3′-azocarbazole (IIf) and diindolo[3,2-a,d]phenazine (IIIf) could not be obtained in these ways. Compound IIf was obtained in Vorländer reaction and IIIf by thermal decomposition of 3-azidocarbazole. Formation of IIIa–IIId is explained as a result of ortho-benzidine rearrangement of hypothetical 9,9′-dialkyl-3,3′-hydrazocarbazoles.
Synthesis of gold nanotubes with variable wall thicknesses
2013
We report the synthesis of gold nanotubes with variable wall thicknesses that is accomplished by the deposition of sacrificial hydrophobic polymer cores followed by gold shells within an anodic aluminum oxide template. We demonstrate that by varying polymer core hydrophobicity, the resulting gold shell thickness can be varied. There are two requirements for gold shell formation: (1) the polymer core must be able to be electrodeposited into a tubular (as opposed to wire-like) structure, and (2) the polymer must be hydrophobic, such that it collapses upon exposure to an aqueous solution. An array of gold nanotubes has variable plasmonic properties and can function as a surface enhanced Raman …
On the origin of functionalization in one-pot radiation synthesis of nanogels from aqueous polymer solutions
2016
Radiation-engineered poly(N-vinyl pyrrolidone) nanogels are very interesting biocompatible nanocarriers for i.v. administration of therapeutics and contrast agents for bioimaging. The manufacturing process is fast and effective, it grants excellent control of particle size and simultaneous sterilization of the formed nanogels. Interestingly, primary amino groups and carboxyl groups, useful for (bio)conjugation, are also formed in a dose-dependent fashion. In this paper, by means of both numerical simulations and experiments, the origin of nanogel size control and functionalization is investigated. This understanding offers a new dimension for the design and production of radiation-sculpture…
Mathematic predictive models for calculating copper, iron and zinc dialysability in infant formulas
2001
Differences in the dialysability of a mineral element from infant formulas of the same type were detected in a previous study. As these may be due to the effects that different levels of the components of the formulas could have on dialysability, we attempted to establish mathematical models to predict the dialysability of Cu, Fe and Zn from infant formulas according to their ascorbic, citric, or selected amino acid contents. A simple linear regression was applied between the ascorbic acid, citric acid and amino acid contents and the Cu, Fe and Zn dialysability of 18 powdered infant formulas of different types. Significant correlations (P<0.05) were obtained between the dialysability of Fe …
Considering lithium-ion battery 3D-printing via thermoplastic material extrusion and polymer powder bed fusion
2021
Abstract In this paper, the ability to 3D print lithium-ion batteries through Pmnbspace thermoplastic material extrusion and polymer powder bed fusion is considered. Focused on the formulation of positive electrodes composed of polypropylene, LiFePO4 as active material, and conductive additives, advantages and drawbacks of both additive manufacturing technologies, are thoroughly discussed from the electrochemical, electrical, morphological and mechanical perspectives. Based on these preliminary results, strategies to further optimize the electrochemical performances are proposed. Through a comprehensive modeling study, the enhanced electrochemical suitability at high current densities of va…
Vapor Pressures of Polymer Solutions and the Modeling of Their Composition Dependence
2009
Equilibrium vapor pressures, p, are reported for the systems tetrahydrofuran + poly(vinyl methyl ether) and tetrahydrofuran + polystyrene at 20, 40, and 60 °C. These data plus information from the literature serve to demonstrate that the composition dependence of p can be modeled quantitatively for polymer solutions in thermodynamically very different solvents by means of three, physically meaningful parameters.
Viscosity of Polymer Solutions over the Full Range of Composition: A Thermodynamically Inspired Two-Parameter Approach
2015
The approach yields the following relation for the relative viscosity η rel as a function of polymer concentration c (mass/volume): ln ηrel = c/(1 + pc + qc2). Reduced concentrations c (defined as c = c[η], where [η] is the intrinsic viscosity) are used instead of c to incorporate thermodynamic information. The parameters p and q account for changes in the free volume of the solvent caused by the polymer. The analysis of literature data for seven very dissimilar systems discloses the following common feature: p > 0 and q < 0. This means that the curves in the plots of ln ηrel as a function of c are normally located below the tangent at low c and above it at high c. The values of p and q cor…
RP-HPLC Determination of Tiger Nut and Orgeat Amino Acid Contents
2005
The amino acid profile of 11 samples of tiger nuts ( Cyperus esculentusL.) grown in the area of “L'Horta Nord” in Valencia (Spain) and one sample of African origin were determined, along with the amino acid contents of 10 samples of natural orgeat from Valencia. Protein was hydrolysed by hydrochloric acid at 110 °C for 23 h, and amino acids were derivatised with AQC and determined by RP-HPLC with fluorescence detection. The chromatographic conditions were optimised. The analytical parameters (detection and quantification limits, precision and accuracy) showed the method to be sufficiently sensitive and reproducible for determining amino acids resistant to acid hydrolysis in tiger nuts and o…