Extraction of iron(III) from acidic sulfate solutions with bis(2‐ethylhexyl)phosphoric acid in PENRECO® 170 ES,a new friendly diluent

The extraction of iron(III) from acidic sulfate solutions by bis(2‐ethylhexyl)phosphoric acid (HDEHP) is investigated by using PENRECO® 170 ES as a diluent. PENRECO® 170 ES is new diluent which offers advantages such as improved solvency power, more complete phase disengagement and reduced losses in aqueous streams, with reductions of over 50% in diluent usage after 1 year, compared with conventional paraffinic diluents. The chemical analyses performed in the present work suggest that such properties arise, at least in part, from the presence of a series of hydrophobic branched alcohols in its composition (at least 0.6 mol dm^?3). In spite of the solvation effects due to these alcohols, HDEHP is dimeric in this diluent and, in the presence of an excess of HDEHP, the extraction of iron(III) takes place according to the classical equation: with K_ex = 10^{5.7 ± 0.2} (at I = 1 mol dm^?3). Such a value of K_ex is similar to that reported for pure hexane, which shows that the presence of long chain alcohols in PENRECO® 170 ES has no perceptible influence on the thermodynamics of iron(III) extraction by HDEHP. The extraction of iron(III) by HDEHP in PENRECO® 170 ES is slightly more rapid than in kerosene, which indicates that the molecules of alcohols constituting PENRECO® 170 ES have no negative effect on the kinetics of metal extraction although they compete with the extractant molecules for adsorption at the liquid–liquid interface. Stripping of iron(III) from loaded organic solutions by sulfuric acid is easy and rapid (95% equilibrium reached within 2 min) when HDEHP is used at moderate concentrations (typically 0.1 mol dm^?3). At higher HDEHP concentrations, stripping is difficult and incomplete, as found previously with other diluents. Thus, PENRECO® 170 ES is interesting in its ability to overcome some of the physical problems encountered in liquid–liquid operations, but its use does not modify significantly the chemistry of iron(III) extraction by HDEHP. © 2002 Society of Chemical Industry     

Field test and evaluation of residential sprinkler systems: Part I

A series of full-scale fire tests involving sprinkler installations was conducted in 1979 and 1980 in a two-story residence in Los Angeles, CA, and in a mobile home in Charlotte, NC. Previous laboratory tests, including full-scale room fire tests, had indicated that a prototype “quick-response” sprinkler was effective in controlling residential home fires. More full-scale fire tests under less controlled and more operational conditions were considered necessary to confirm or deny these scientific and engineering judgments. The prime objective of the program was to test the performance of alternative sprinkler designs to “control” the development of fire in single-family dwellings and mobile homes. National Fire Protection Association Editor's Note: This paper is the first of three papers reporting on full-scale residential sprinker fire tests conducted under Grant 79027 for the U.S. Fire Administration by the National Fire Protection Association. In this paper, the objectives of the test program are outlined; the test facilities, Prototype sprinkler, water supplies, sprinkler system design, and instrumentation are described; and the scenarios for the total of seventy-six tests conducted are summarized. The second paper (February 1984 issue) will focus on the results of the test and the conclusions drawn from them and the third (May 1984 issue) will cover a study of the comparative activation times of sprinklers and smoke detectors in the mobile home tests. Mr. Cote is Assistant Vice President (Engineering & Technical Services) for the NFPA. He served as project manager for the test series insofar as the NFPA had overall management responsibilities for the program.     

THERMODYNAMIC STUDY OF THE EXTRACTION OF INDIUM(III) AND CADMIUM(II) BY CYANEX 301 FROM CONCENTRATED HCl MEDIA

ABSTRACT

The distribution equilibria of In(III) and Cd(II) between aqueous HCl solutions and kerosene containing Cyanex 301 (bis(2,4,4-trimethylpentyl) dithiophosphinic acid denoted hereafter HL) and 10 % (V/V) of n-decanol are investigated. In(III) and Cd(II) are extracted as InL₃ and CdL₂, respectively and a physico-chemical model is proposed for modelling the distribution data. In the final part of the paper, this, model is used to discuss the optimal conditions for separating indium and cadmium, previously co-extracted with Cyanex 301, by stripping in HCl media.     

Influence of physico-chemical,mechanical and morphological fingerpad properties on the frictional distinction of sticky/slippery surfaces

This study investigates how the fingerpad hydrolipid film, shape, roughness and rigidity influence the friction when it rubs surfaces situated in the slippery psychophysical dimension. The studied counterparts comprised two ‘real’ (physical) surfaces and two ‘virtual’ surfaces. The latter were simulated with a tactile stimulator named STIMTAC. Thirteen women and 13 men rubbed their right forefingers against the different surfaces as their arms were displaced by a DC motor providing constant velocity and sliding distance. Tangential and normal forces were measured with a specific tribometer. The fingerpad hydrolipid film was characterized by Fourier transform infrared spectroscopy. The shape and roughness of fingers were extrapolated from replicas. Indentation measurements were carried out to determine fingerpad effective elastic modulus. A clear difference was observed between women and men in terms of friction behaviour. The concept of tactile frictional contrast (TFC) which was introduced quantifies an individual''s propensity to distinguish two surfaces frictionally. The lipids/water ratio and water amount on the finger skin significantly influenced the TFC. A correlation was observed between the TFC and fingerpad roughness, i.e. the height of the fingerpad ridges. This is essentially owing to gender differences. A significant difference between men''s and women''s finger topography was also noted, because our results suggested that men have rougher fingers than women. The friction measurements did not correlate with the fingerpad curvature nor with the epidermal ridges'' spatial period.     

HYDROMETALLURGY OF STRATEGIC METALS

ABSTRACT

This paper gives a short overview of the importance of solvent extraction in the production and recycling of strategic metals. Both the present situation and possible developments are considered. The use of solvent extraction in the processing of powdered metal-containing materials with tailor-made characteristics is also discussed as it is attracting increasing attention.     

Glucose monitoring using implanted fluorescent microspheres

The authors are working toward a minimally invasive means for diabetics to better monitor glucose levels. A fiber-optic probe was fabricated for delivery and collection of light to an implanted sensor. The probe and associated optical system has high sensitivity and allows for flexible, remote measurements. The system was used to collect data with sensor solutions similar to what is envisioned for the implantable system, and the recorded spectra were processed in an attempt to predict glucose concentrations from fluorescence measurements. Despite the availability of sophisticated multivariate calibration methods, the best prediction results were obtained using polynomial regression with regression coefficient ratios. The measurements are far from perfect, but they do meet the requirements for clinical use and show promise for further improvement in the future. In vivo experiments were conducted using "simulated" sensors that had constant fluorescence characteristics. Results of implantation in excised skin and in live animals indicate that, while very strong fluorescence signals were measured for implanted particles, the current sensor chemistry must be improved for adequate resolution. In addition, difficulty in achieving repeatable injection depths and homogeneity of mixtures containing different colored spheres confounded attempts to make true quantitative measurements.     

The computer approach to fire protection problems

With computers coming into more widespread use every day, it is only logical that they find applications in the field of fire protection. They have, in fact, already been used for computing sprinkler system requirements. The authors relate how The Travelers employs the computer and suggest applications to be explored in the future. The Travelers Insurance Companies Note: This paper was presented at the annual meeting of the Society of Fire Protection Engineers at Boston, Mass., on May 18, 1967, as part of a program arranged by the New England Chapter of the SFPE.     

A novel approach to complex target recognition using RCS wavelet decomposition

A novel approach to complex target recognition using wavelet decomposition of the radar cross section is introduced. The analysis technique is presented, and it shown how it can be implemented using MATLAB software. Applications in the radar field are then investigated, both for simple and complex targets. The results obtained show that this technique is very promising and yields recognition levels difficult to achieve with any other available technique.     

Extraction of Lanthanides(III) and Am(III) by Mixtures of Malonamide and Dialkylphosphoric Acid

Abstract

N,N′‐dimethyl‐N,N′‐dioctylhexylethoxymalonamide, DMDOHEMA, and di‐n‐hexylphosphoric acid, HDHP, are the extractants of reference for the French DIAMEX–SANEX process for the separation of trivalent actinide ions from the lanthanide ions. In this work, the extraction of Eu³⁺ and Am³⁺ by the two extractants, alone or in mixtures, has been investigated under a variety of experimental conditions. The two cations are extracted by HDHP as the M(DHP · HDHP)₃ complexes with an Eu/Am separation factor of ～10. With DMDOHEMA, Eu³⁺ and Am³⁺ are extracted as the M(NO₃)₃(DMDOHEMA)₂ disolvate species with an Am/Eu separation factor of ～2. The metal distribution ratios measured with a mixture of the two reagents indicated that almost all lanthanides are extracted equally well. The extraction of Eu³⁺ and Am³⁺ by HDHP‐DMDOHEMA mixtures exhibits a change of extraction mechanism and a reversal of selectivity taking place at ～1 M HNO₃ in the aqueous phase. Below this aqueous acidity, HDHP dominates the metal extraction by the mixture, whereas DMDOHEMA is the predominant extractant at higher aqueous acidities. Some measurements indicated apparent modest antagonism between the two extractants in the extraction of Eu³⁺ and synergism in the extraction of Am³⁺. These data were interpreted as resulting from the formation in the organic phase of mixed HDHP‐DMDOHEMA species containing two HDHP and five DMDOHEMA molecules.