Development of mica-based porous polymeric membrane and their application

To develop porous polymeric membrane, we have used poly(vinylidene-co-hexafluoropropylene) (P(VdF-HFP)) as a host matrix and the ionic liquid 1-ethyl-3-methylimidazolium tosylate as salt for the source of charge carriers in the polymer electrolyte system. Appropriate weight of mica (muscovite) has been added to the highest conducting polymer–salt electrolyte. The composite membrane has been prepared by breath figure method through controlling evaporation time and then tested this membrane for water filtration. The composite polymeric membrane has been characterized by X-ray diffraction, FTIR spectrometry, SEM, and electrochemical impedance spectroscopy. The pore volume in the mica-based film has been calculated, and it is found to be 64.3 % in the filler-dispersed membrane.     

Computing simple paths among obstacles

Given a set X of points in the plane, two distinguished points s,tX, and a set Φ of obstacles represented by line segments, we wish to compute a simple polygonal path from s to t that uses only points in X as vertices and avoids the obstacles in Φ. We present two results: (1) we show that finding such simple paths among arbitrary obstacles is NP-complete, and (2) we give a polynomial-time algorithm that computes simple paths when the obstacles form a simple polygon P and X is inside P. Our algorithm runs in time O(m²n²), where m is the number of vertices of P and n is the number of points in X.     

Oxidation ofα-hydroxy acids and derivatives by Cr(VI) oxide

The kinetics of the chromic acid oxidation ofα-hydroxy acids, their salts and esters has been investigated in binary solvent mixtures of acetic acid and water. The results indicate that the Westheimer hypothesis of a rate-determining proton-abstraction from a preformed chromate ester is unlikely. Substituent and salt effects indicate the likelihood of a mechanism involving a rate-determining hydride ion abstraction assisted by a proximate substituent.     

Free energy relationship in some electron-transfer reactions

A linear logarithmic dependence of the standard rate constant on the apparent free energy of activation for the electrode process has been observed for the reduction of zinc in the presence of alanine, glycine, aspartic acid, glutamic acid, ammonia, ethylenediamine and tartrate. The value of the slope is close to the transfer coefficient of zinc in these media. For a homogeneous electron-exchange reaction, such as the disproportionation of uranium(V) in solution, a linear free energy relation has been observed.     

Transition metal ions in crystals: A refined treatment and deduction of coulomb and exchange interaction constants

Making use of Racah's irreducible tensor operator technique a refined treatment for the 3d-transition metal ions in crystals has been presented. The refined theory has been applied to analyse the recently observed fine optical spectra of MgF₂:Co²⁺ and MgF₂:Mn²⁺. Important differences have been noticed in the assignments of the optical lines obtained from the present analysis and from the conventional three-parameter theory. First numerical values of the exchange and Coulomb integrals in these systems have also been given.     

On directly measuring relative Fermi energies of noble metals and their alloys

We present the first evidence of direct measurement of relative Fermi energies in alloys and between pure metals. From applying the “atomic” concept of core hole final state screening, the Auger energy shift of noble metal A equals E_F^A?E_F(x). High resolution Auger shifts in P_1?x^tCu_x,Au_xCu_1?x and Au_xAg_1?x demonstrate experimental verification of this simple relation. We find E_F^CuE_F^Au ? ? 0.2 eV, and E_F^Pt ? E_F^Cu and E_F^Ag ? E_F^Au.     

Electron-impact-induced hydrogen migration in organic molecules. II—novel hydrogen migration in dihydro-2-stilbazole derivatives

The mass spectra of 2′-OH, 2′-NH₂ and 2′-CH₃-dihydro-2-stilbazole derivatives show an interesting hydrogen migration. The hydrogen migration is shown to be taking place from the above mentioned substituents to the nitrogen of the pyridine ring followed by a β-cleavage giving rise to a common ion e at m/e 93, perhaps through an 8-membered transition state.     

A new route to furanoeremophilane sesquiterpenoids. Synthesis of (+/-)-6[small beta]-hydroxyeuryopsin

The naturally occurring furanoeremophilane 6[small beta]-hydroxyeuryopsin was synthesized by a novel route which involved Stille coupling of a 2-furylstannane with a cyclohexylmethyl bromide, followed by intramolecular formylation of the furan to complete the tricyclic nucleus of the sesquiterpenoid.