Deformation and strain analysis for high extrusion ratios and elevated temperatures

A method is described for obtaining full-field distribution of strain during axisymmetric extrusion. Strains are determined from changes in the shapes of flowlines as observed through the deformation of an ink-stamped grid on an axial plane of the extruded billet. Numerical methods are described for approximation and differentiation of the materialflow functions. The method is applied to extrusion of aluminum at 430°C with an extrusion ratio of 12.4 to 1. Good agreement is found between calculated and measured flow patterns.     

Fuzzy logic for auditory evoked response monitoring and control of depth of anaesthesia

This paper describes a self-organizing fuzzy model of patients undergoing surgery which was created from 10 clinical trials with off-line analysis during maintenance of anaesthesia using the drug propofol. The effects of patient sensitivity and surgical disturbances are also represented in this patient model. Hence, this model can be considered to be a qualitative pharmacologically related model for propofol during the anaesthetic maintenance stage. Furthermore, a closed-loop simulation has been designed to validate the patient model and compare the performance of a self-organizing fuzzy logic controller algorithm against a clinically derived linguistic controller. The successful results obtained provide proof-of-concept and encouragement to perform on-line clinical trials using fuzzy logic-based monitoring and control in operating theatre in the near future.     

The fluoride ion affinity of tungsten pentafluoride and the electron affinity of tungsten hexafluoride.

Enthalpies of oxidative alkaline hydrolysis of the salts LiWF₆ and NaWF₆ are −549 and −519 kj mol^-1 respectively. From these results and earlier thermochemical results for KWF₆, RbWF₆, and from crystal structure data for these salts, it has proved possible to assess the charge distribution within the WF₆^- anion in these salts, and to estimate the fluoride ion affinity of WF₅ and the electron affinity of WF₆.     

The solution thermochemistry of antimony pentafluoride and some fluoroantimonates

From hydrolysis and solution measurements the enthalpies of formation of SbF₅(?), LiSbF₆(s), NaSbF₆(s), KSbF₆(s), CsSbF₆(s), AgSbF₆(s), and SbF₆^?aq. are estimated to be ?1324 ± 12, ?2062 ± 5, ?2060 ± 6, ?2080 ± 3, ?2082 ± 15, ?1653 ± 3, and ?1789 ± 4 kJ mol^?1 respectively. Less precise estimates of the enthalpies of formation of O₂SbF₆ and of CsSb₃F₁₆ are also given. From the results the fluoride ion affinity of SbF₅, the single ion hydration enthalpy of SbF₆^? (g), and the charge distribution within the SbF₆^? ion have been calculated.     

Core electron transitions as a probe for molecular chirality: natural circular dichroism at the carbon K-edge of methyloxirane

We have measured for the first time the X-ray natural circular dichroism (XNCD) of a chiral molecule in an isotropic medium. In this condition the only surviving term contributing to CD is the cross product between the electric dipole and the magnetic dipole transition moments. The non-zero value of the magnetic dipole transition moment in a 1s-to-valence electron transition is attributed to contribution of valence states to core molecular orbitals. These results open the way to a "local" chiral molecular analysis and to the study of stereochemically selected photochemical processes.     

Absorption, Circular Dichroism, and Luminescence Spectroscopy of Electrogenerated Delta-[Ru(bipy)(3)](+/0/)(-) and Delta-[Os(bipy)(3)](+/0/)(-) (bipy = 2,2'-Bipyridine)

The electronic absorption and circular dichroism (CD) spectra of the complexes produced by the one, two, and three electron reduction of Delta-[Ru(bipy)(3)](2+) and Delta-[Os(bipy)(3)](2+) are reported. The CD spectra give unequivocal proof that the added electrons are localized on individual bipiridine ligands and thus that the complexes are correctly formulated [M(bipy)(2)(bipy(-))](+), [M(bipy)(bipy(-))(2)](0), and [M(bipy(-))(3)](-). The absorption spectra of the triply reduced species [M(bipy(-))(3)](-) (M = Ru, Os) are compared to those of the Fe(II) and Ir(III) analogs. The luminescence spectra of the two triply reduced complexes [Ru(bipy(-))(3)](-) and [Os(bipy(-))(3)](-). are also presented. The MLCT luminescence found in the parent complexes is completely quenched and is replaced by a weak luminescence attributed to the pi(10) --> pi(7) transition of the (coordinated) [bipy](-) ion.     

The location of the 1Lb transition of anthracene by dichroism techniques

Measurements of the linear dichroism of anthracene in an stretched polythene film, the magnetic circular dichroism of the hydrocarbon in a range of solvents, including those giving Ham effect, and the mesophase-induced circular dichroism of the hydrocarbon in a cholesteric solvent, place the origin of the ¹L_b transition near 28 kK, some 1500 cm^?1 to the blue of the ¹L_b origin, contrary to recent assingments locating the ¹L_b origin at 25 kK.     

Further studies on the taumerization of the hydrido (alkynyl) cluster Ru3Pt(μ-H) {μ4-ν2-C ≡ C1Bu} (CO)9(L2) to the vinylidene cluster Ru3Pt{μ4-ν2-C ≡ C(H)tBu} (CO)9(L2): X-ray structures of Ru3Pt(μ-H){μ4-ν2-C = C(H)tBu} (CO)9(L2); L2 = dppet,dppp, andS,S-dppb

The first order rate constants for the tautomerization of the hydrio(alkynyl) clusters Ru₃Pt(μ-H){μ₄-ν²-C ≡ C¹Bu}(CO)₉(L₂);1a: L₂ = dppe,1b; L₂ = dppet,1c; L₂ = dppp and1d; L₂ =S,S-dppb to the corresponding vinylidene clusters Ru₃Pt{μ₄-ν²-C = C(H)^tBu}(CO)₉(L₂)2 have been measured, and they follow the orser1d <1a <1b ～1c. The reactions involving1a and1d exhibit an inverse kinetic deuterium isotope effect. The structures of1b, 2b, 2c, and2d were determined by X-ray crystallography, and are compared with those of1a and2a which have been previously reported. Crystal data for1b, space groupPbca,a = 13.338(4) Å,b = 17.771(6) Å,c = 36.092(8) Å,Z = 8,R(R _w) = 0.059(0.058) for 2342 absorption corrected, observed data; for2b, space group P2₁/n,a = 10.566(2) Å,b = 20.234(5) Å,c = 20.270(3) Å,β = 96.11(1)°,Z = 4,R(R _w) = 0.043(0.053) for 5865 absorption corrected, observed data; for2c, space group P2₁/n,a = 14.211(5) Å,b = 19.534(2) Å,c = 15.870(2) Å,β = 100.81(2)°,Z = 4,R(R _w) = 0.055(0.031) for 6566 absorption corrected, observed data: for2d, space group P2₁2₁2₁,a = 12.309(4) Å,b = 19.047(6) Å,c = 19.206(4) Å,Z = 4,R(R _w) = 0.055(0.053) fpr 2151 absorption corrected, observed data. The fluxional behavior of1d and1e (which consists of two interconverting isomers) has been examined by variable temperature¹³C NMR spectroscopy and by³¹P EXSY.