Determination of soluble and insoluble zirconium in magnesium alloys

A method for the determination of soluble and insoluble zirconium is described. To differentiate between the two forms, two solutions are prepared, in one of which the insoluble zirconium remains in suspension ; in the other it is brought into solution with hydrofluoric acid. Zirconium is extracted by trioctyl phosphine oxide/petroleum ether and determined in the extract spectrophotometrically with pyridyl-azo-naphthol (PAN) as reagent.     

Fluctuations in inelastic proton scattering from58Ni in the energy range 17.1 to 20.6 MeV

Excitation functions of proton elastic and inelastic scattering on⁵⁸Ni have been measured for proton energies in the range 17.1 to 20.6 MeV, at laboratory angles of 90°, 120° and 155°. All show cross section fluctuations. Excitation functions are presented for the elastic and for five inelastic groups in the energy range 18.1 to 18.59 MeV. These were analyzed by the Fourier analysis method, and the average level width found to be about 13 keV. The observation of strong fluctuations in the higher inelastic yields has implications for several microscopic analyses reported in the literature of⁵⁸Ni(p, p′) data obtained at 17.7 MeV incident proton energy.     

Electrochemical studies on ion-selective polymer membrane electrodes

The selectivity and response of neutral carrier based polymer membrane electrodes are investigated via exchange current measurements for systems containing valinomycin, dibenzo-18-crown-6, and plasticizer alone in a polyvinyl chloride matrix. Using a transient galvanostatic step method, apparent exchange current densities of 1.3 X 10^?3 A/cm², 5.4 X 10^?6 A/cm², and 2.2 X 10^?9 A/cm² were obtained with K⁺ as the primary ion for the three types of membranes, respectively. Preliminary results indicate that the exchange current data obtained with this technique are complementary to the potentiometric response observed for the membranes studied.     

Regioselective synthesis of substituted pyrroles: efficient palladium-catalyzed cyclization of internal alkynes and 2-amino-3-iodoacrylate derivatives

The first efficient and regioselective palladium-catalyzed cyclization of internal alkynes and 2-amino-3-iodoacrylates to give moderate to excellent yields of highly functionalized pyrroles has been developed. This approach is applicable to a range of alkynes and affords the deacylated pyrrole under reaction conditions for most substrates. [reaction: see text]     

Nuclear stopping power in αα anddd collisions

Inelasticαα anddd collisions were studied at a centre-of-mass energy √S _NN=31.2 GeV per nucleon-nucleon collision, using the Split-Field Magnet (SFM) detector at the CERN ISR. In this paper we show the inclusive and semi-inclusive rapidity distributions of protons, compare them with predictions of the Lund model, and calculate the average rapidity loss for participant protons. From the negative particles we calculate the inelasticity of the interaction, the average energy per particle, and the degree of isotropy of the produced hadrons.     

The four-jet structure of large transverse momentum events inpp interactions at the ISR

Deep inelastic proton-proton collisions have been recorded with the Split-Field-Magnet Detector (SFM) at the CERN Intersecting Storage Rings (ISR) by triggering on a single particle at high transverse momentum. Full reconstruction of the charged particles in these collisions was performed. In this paper we demonstrate the existence of a structure comprised of four jet-like clusters, two longitudinal and two transverse with respect to the beam, as would be expected from hard scattering of proton constituents.     

On-line pre-concentration of atrazine by antibody immobilization capillary electrophoresis

Antibody coupled capillary electrophoresis was employed in the pre-concentration and detection of atrazine at the parts per billion (ppb) level. A 1000-fold increase in detection has been demonstrated in the use of IgG anti-atrazine monoclonal antibodies for the analysis of atrazine in well water by capillary zone electrophoresis (CZE) with UV-VIS detection. These results were confirmed by an enzyme linked immunosorbent assay (ELISA) specific for atrazine.     

Determination of nitrogen in steel

The accuracy of the measurement of small amounts of nitrogen in steel by chemical methods is dependent on satisfactory procedures for converting the nitrides into ammonia, and for measuring the ammonia thus formed.In the method proposed for the latter, Nessler's reagent is used and the intensity of colour is measured on an absorptiometer. For maximum accuracy, variables such as temperature and time of standing before measurement, must be carefully controlled.