Extraction equilibria in the system GaCl3-AlCl3-HCl-H2O-tributyl phosphate

Partition equilibria and solution chemistry of the system GaCl₃-AlCl₃-HCl-H₂O-tributyl phosphate is characterized by a simultaneous extraction of gallium chloride, hydrochloric acid, and water by a solvating mechanism. The salting-out power of the aqueous phase was explained by taking into account the stability of aluminum chloride and gallium chloride complex species and the calculated concentration of free chloride ions actually available for the extraction of gallium. Three gallium extraction mechanisms in the range of compositions studied are the extraction of GaCl₃ at low H⁺ and salt concentrations, the extraction of GaCl^- ₄ at moderate H⁺ and salt concentrations, and the competition between the extraction of GaCL^-4 and an HC1-TBP complex at high H+ and salt concentrations. The extraction of gallium over a wide range of distribution ratios (D = 1 to 1 x 10⁴) could be represented by a chemically based model taking into account the free chloride concentration and the activity coefficient of the total chloride ions. Formerly Visiting Scientist, Ames Laboratory, USDOE     

Electric-power quality measurements under distorted conditions:: Are they utopia or reality?

This paper discusses how distortion- and unbalance-dependent parameters can be used for assessing the electric-power quality. In particular, possible ways for the localization of the sources producing distortion are discussed. The information supplied by the different measurement procedures proposed in the literature or by the International Standards is compared, on the basis of experimental results. The discussion is aimed at outlining items that have not yet been studied in a satisfactory way.     

An Efficient Heuristic Approach to Recognize the Infeasibility of a Loading Problem

The success of hierarchical production planning approaches for flexible manufacturing systems lies in the consistency of decision outcomes at various decision levels. For instance, the loading problem, which is solved at a lower level, may not yield a feasible loading solution to a set of part types selected at a higher level. This paper attemps to address the issue of recognizing the infeasibility of a loading solution. We present a modified loading model that includes a penalty for each operation not assigned to any machine. We develop a Lagrangian-based heuristic procedure and provide a sufficient condition on the quality of heuristic solutions that, if satisfied, will enable us to use the heuristic solutions to recognize the infeasibility of a loading problem. The proposed model and the dual-based heuristic can be effectively incorporated in an FMS hierarchical production planning approach that finds a good loading solution by iteratively comparing different part grouping scenarios.     

Aryl Bis‐Sulfonamide Inhibitors of IspF from Arabidopsis thaliana and Plasmodium falciparum

2‐Methylerythritol 2,4‐cyclodiphosphate synthase (IspF) is an essential enzyme for the biosynthesis of isoprenoid precursors in plants and many human pathogens. The protein is an attractive target for the development of anti‐infectives and herbicides. Using a photometric assay, a screen of 40 000 compounds on IspF from Arabidopsis thaliana afforded symmetrical aryl bis‐sulfonamides that inhibit IspF from A. thaliana (AtIspF) and Plasmodium falciparum (PfIspF) with IC₅₀ values in the micromolar range. The ortho‐bis‐sulfonamide structural motif is essential for inhibitory activity. The best derivatives obtained by parallel synthesis showed IC₅₀ values of 1.4 μm against PfIspF and 240 nm against AtIspF. Substantial herbicidal activity was observed at a dose of 2 kg ha^?1. Molecular modeling studies served as the basis for an in silico search targeted at the discovery of novel, non‐symmetrical sulfonamide IspF inhibitors. The designed compounds were found to exhibit inhibitory activities in the double‐digit micromolar IC₅₀ range.     

Gate delay variability estimation method for parametric yield improvement in nanometer CMOS technology

In digital CMOS circuits, parametric yield improvement may be achieved by reducing the variability of performance and power consumption of individual cell instances. Such improvement of variation robustness can be attained by evaluating parameter variation impact at gate level. Statistical characterization of logic gates are usually obtained by computationally expensive electrical simulations. An efficient gate delay variability estimation method is proposed for variability-aware design. The proposed method has been applied to different topologies (transistor network arrangements) and CMOS gates, and it has been compared to Monte Carlo simulations for data validation, resulting in computation time savings.     

Thermodynamic Evaluation of the Phase Stability and Microstructural Characterization of a Cast B1914 Superalloy

The boron-carbon superalloys (BC alloys) were developed to reduce the carbon content of the alloys to less than 0.02 wt.% and increase the boron content to 0.1 wt.% in some Ni-based superalloys. In this study, we have used characterization techniques, such as DTA, XRD, SEM coupling, and thermodynamic calculation using Thermo-Calc software, to obtain information about the phase transformation reaction temperatures and the elemental compositions of the microstructural constituents encountered in the B1914 superalloy. The microstructure of the B1914 superalloy was composed of a gamma (γ) phase with a dendritic structure and gamma prime (γ′) phase with a cuboidal shape. Precipitates of γ′ and a lamellar eutectic, composed of γ/(Mo,Cr,Ni)₃B₂, were identified in the interdendritic region. The thermodynamic calculation results have shown to be a valuable tool for predicting the transformation temperature, such as liquidus, γ’ solvus, and incipient melting point. These transformations are important parameters used in casting simulation software for determining the heat treatment and welding repair conditions for parts made from this alloy.     

Identification and analysis of isothiocyanates and new acylated anthocyanins in the juice of Raphanus sativus cv. Sango sprouts

The freeze-dried sprouts’ juice of Raphanus sativus (L.) cv. Sango was prepared and analysed for the first time. HPLC analysis of total isothiocyanates, after protein displacement, resulted in 77.8 ± 3.0 μmol/g of dry juice while GC–MS analysis of hexane and acetone extracts showed E- and Z-raphasatin (8.9 and 0.11 μmol/g, respectively) and sulforaphene (11.7 μmol/g), summing up to 20.7 ± 1.7 μmol/g of free isothiocyanates. Sprouts’ juice contained an unprecedented wealth of anthocyanins and a new fractionation methodology allowed us to isolate 34 mg/g of acylated anthocyanins (28.3 ± 1.9 μmol/g), belonging selectively to the cyanidin family. Analysis was performed by HPLC–PDA–ESI–MSⁿ and extended to deacylated anthocyanins and aglycones, obtained, respectively, by alkaline and acid hydrolysis. This study identified 70 anthocyanins, 19 of which have never been described before and 32 of which are reported here in R. sativus for the first time. Sango radish sprouts are exceptional dietary sources of heath-promoting micronutrients.     

Characterization of Crude Watermelon Seed Oil by Two Different Extractions Methods

The aim of this paper was to study the physical–chemical composition of the watermelon seed oil extracted by a mechanical process using an expeller and by a chemical process using hexane as the solvent. The watermelon seed oil had a high concentration of unsaturated fatty acids. The two primary sterols were stigmasterol and β-sitosterol, which corresponded to approximately 47 and 30% of the total phytosterols. The oil had a low tocopherol content (65.19 mg/kg for S and 73.19 mg/kg for E). Comparing the two extraction methods, extraction by expeller produced an oil of superior quality with respect to oxidative stability, carotenoids and Lovibond color. No significant differences were found between the two extraction methods with respect to the minor components of the oil considered as functional, such as phytosterols.     

Easy mass spectrometry for metabolomics and quality control of vegetable and animal fats

Easy ambient sonic spray ionization (EASI), a novel desorption/ionization technique for ambient mass spectrometry analysis, is shown to permit the characterization of different types of vegetable and animal fats. The taxonomic markers of the oils, mainly fatty acids and phenols, are extracted with methanol/water (1:1) solution and made alkaline with NH₄OH, then placed and dried on the surface of a glass tip and directly analyzed by EASI‐MS in the negative‐ion mode. EASI provides a supersonic cloud of charged droplets that causes efficient desorption and ionization of the oil markers directly from the surface of the glass tip. As proof‐of‐principle cases, EASI(?)‐MS was applied to genuine samples of olive oil, hazelnut oil, soybean oil, grape seed oil, canola oil, butter, and lard. Characteristic metabolomics EASI(?)‐MS profiles of fatty acids and eventually phenols were obtained.