Characterization of fatty oils by pattern recognition of triglycerides profiles

The triglyceride profiles for corn, soybean, sunflower, grapestone, olive and olive husks oils were obtained by high temperature capillary gas chromatography on HT-FS capillary columns coated with OV-17-OH. The data were treated by methods of computerized pattern analysis, involving principal component analysis, discriminant analysis, and hierarchical clustering. A graphical representation of results as “star symbol plots” allows prompt visual recognition of the characteristic profiles and straightforward qualitative identification of unknowns as well as recognition of adulterations.     

Quantum yield of Cl* (2P1/2) production in the gas phase photolysis of CCl4 in the ultraviolet

In this paper, we have probed the dynamics of chlorine atom production from the gas phase photodissociation of carbon tetrachloride at 222 and 235 nm. The quantum yield, φ* of Cl* (²P_1/2) production has been determined by probing the nascent concentrations of both excited (²P_1/2) and ground state (²P_3/2) chlorine atoms by suitable resonance-enhanced multiphoton ionization (REMPI) detection schemes. Although at the photolysis wavelengths the absorption of carbon tetrachloride is weak, significant amounts of Cl* are produced. Surprisingly, the quantum yield of Cl* production does not follow the absorption spectrum closely, which gives rise to the possibility of an indirect dissociation mechanism present in CCl₄ along with direct dissociation at these ultraviolet wavelengths     

Calorific study of the smectic A—smectic C transition in TBBA

An a.c. calorimetric technique has been used to measure the heat capacity variation associated with the smectic A—smectic C transition in terephthal-bis-(4n)-butylaniline (TBBA). Contrary to expectations based on the recent observation of petransitional acoustic effects in the semectic-A phase, the heat capacity shows no evidence of critical fluctuations and can be well described by a Landau mean-field model.     

Trans-bis(dimethylglyoximato) cobalt(III) complexes containing imidazole and thiocyanate as axial ligands

Imidazole(Im), benzimidazole(BzIm), morpholine (Morph) and their derivatives react with Co(CNS)₂ and dimethylglyoxime(DH₂) in ethanolic medium in presence of air to form a number of new cobalt(III) complexes of the type trans-[Co(DH)₂(L)(SCN)], which are characterised on the basis of electronic and IR spectra, NMR (¹H and ¹³C) and mass spectra as well as thermogravimetric (TG-DTA) and conductance measurements. The thiocyanate groups are S-bonded. The NMR observations suggest that in solution these compounds exist as mixtures of the neutral species [Co(DH)₂(L)(SCN)] and the salt [Co(DH)₂(SCN)₂]^? [Co(DH)₂(L)₂]⁺. The mass spectra does not show the molecular ion peak of the complex. The TG-DTA measurements show that the thermolysis of these complexes proceeds through polymeric intermediates giving CO₃O₄ as the end product.     

Hartree-Fock cluster investigation of location and hyperfine properties of normal muonium in silicon-trend with respect to diamond

Using the first-principles Hartree-Fock Cluster procedure employed earlier for normal muonium (Mu) in diamond, the total energy and hyperfine field at the muon site in silicon have been studied as a function of muon position along the <111> direction. The muon was found to be localized in the tetrahedral interstitial region, although the potential was significantly shallower as compared to diamond. The vibrationally averaged hyperfine constant for the muon shows a correct trend compared to diamond but is somewhat larger than experiment, possible reasons for which will be discussed. Results for the superhyperfine constants in silicon will be presented and compared with those for diamond.