Significance of Deuteron Breakup in Halo Transfer

 We discuss the quasi-adiabatic approximations to the three-body wave-function in breakup processes and clarify the assumptions underlying the model. This suggests alternative approximation schemes. Using different theoretical three-body models, calculated angular distributions of differential cross sections for the ¹¹Be(p,d) reaction are presented, for which new preliminary data have been reported at 35 MeV. We show that calculations are sensitive to the inclusion of deuteron breakup and to the breakup model used, particularly if absolute spectroscopic information on the 0⁺ and 2^{+ 10}Be core-state parentages is deduced. There is also considerable sensitivity to the model employed in calculations of the relative cross sections of the two states. Received January 19, 1999; revised April 16, 1999; accepted for publication February 28, 2000     

Hybrid finite element/volume method for 3D incompressible flows with heat transfer

An implicit hybrid finite element (FE)/volume solver has been extended to incompressible flows coupled with the energy equation. The solver is based on the segregated pressure correction or projection method on staggered unstructured hybrid meshes. An intermediate velocity field is first obtained by solving the momentum equations with the matrix-free implicit cell-centred finite volume (FV) method. The pressure Poisson equation is solved by the node-based Galerkin FE method for an auxiliary variable. The auxiliary variable is used to update the velocity field and the pressure field. The pressure field is carefully updated by taking into account the velocity divergence field. Our current staggered-mesh scheme is distinct from other conventional ones in that we store the velocity components at cell centres and the auxiliary variable at vertices. The Generalized Minimal Residual (GMRES) matrix-free strategy is adapted to solve the governing equations in both FE and FV methods. The presented 2D and 3D numerical examples show the robustness and accuracy of the numerical method.     

Stability analysis for several second-order Sigma—Delta methods of coarse quantization of bandlimited functions

We investigate the stability and robustness properties of a family of algorithms used to “coarsely quantize” bandlimited functions. The algorithms we will consider are one-bit second-orderΣΔA-quantization schemes and some modified versions of these. We prove that there exists a bounded region that remains positively invariant under the two-dimensional piecewise-affine discrete dynamical system associated with each of these quantizers. Moreover, this bounded region can be constructed so that it is robust under small changes in the quantizer. We also show some interesting properties of the resulting binary sequences.     

Hydrogen ion-selective poly(vinyl chloride) membrane electrode based on a p-tert-butylcalix[4]arene-oxacrown-4

A hydrogen ion-selective poly(vinyl chloride) (PVC) membrane electrode was developed using p-tert-butylcalix[4]arene-oxacrown-4 as ionophore. Apart from the ionophore, plasticisers and lipophilic anions were blended, in various proportions, with PVC in tetrahydrofurane and mixtures so prepared were poured onto glass surfaces to form the membrane. 2-Nitrophenylpentylether has proved to be the best alternative as plasticiser and the lipophilic anions tried have turned out to have an adverse effect on the pH response. The electrode of the optimum characteristics had a composition of 2% p-tert-butylcalix[4]arene-oxacrown-4, 68.3% o-NPPE and 29.7% PVC. The electrode showed an apparent Nernstian response in the pH range 2-11 with a slope of 54.2±0.4 mV pH⁻¹ at 20±1 °C. It has a rapid potential-response to changes of pH, high ion selectivity towards lithium, sodium and potassium, and other characteristics comparable to those reported for the conventional pH glass membrane electrode. It appears to be a suitable potentiometric indicator electrode specifically for hydrofluoric acid solutions.     

Angiotensin converting enzyme I/D, angiotensinogen T174M-M235T and angiotensin II type 1 receptor A1166C gene polymorphisms in Turkish hypertensive patients

Essential hypertension is a multifactorial disease in which genetic and enviromental factors play an important role. These factors differ in each population. As there are no existing data for the Turkish population, we investigated four Renin Angiotensin System (RAS) gene polymorphisms, the angiotensin converting enzyme (ACE), angiotensinogen (AGN) M235T/T174M and angiotensin II type 1 receptor A1166C polymorphism in 109 hypertensive and 86 normotensive Turkish subjects. Polymerase Chain Reaction (PCR) and Restriction Fragment Length Polymorphism (RFLP), and agarose gel electrophoresis tecniques were used to determine these polymorphism. The frequencies of person that carry ACE D allel (DD+ID) was significantly higher in hypertensive group (99.1%) than controls (80%) (P 0.000). M235T TT genotype was also found significantly higher in hypertensives than control group (20% vs 2.7%; P 0.001). The frequency of AGN 174M allele was higher in the hypertensive group than control subjects (8.76% vs 4.81%). Frequency of ATR1 C allele (AC+CC genotypes) was found higher hypertensives than controls (39.4% vs 25.9%; P = 0.054). Our results suggest that an interaction exists between the RAS genes and hypertension in Turkish population.     

An integrated process for partial oxidation of alkanes

The partial oxidation of alkanes via bromination followed by the reaction with solid metal oxide mixtures (MO) is shown to give an array of products that can be tuned by varying the MO and the reaction conditions.     

Numerical solution of Navier-stokes equations for laminar fluid flow in rows of plates in staggered arrangement

Laminar fluid flow in rows of plate elements with staggered arrangement has been investigated by solving the complete Navier-Stokes equations using numerical methods. The results have been compared with those obtained on the basis of boundary-layer simplifications. The theoretical pressure-drop values compare well with available numerical and experimental data     

Synthesis of R-(-)-2-Ethyl-N-benzyl (monoaza-15-crown-5) and the Crystal Structure of Its Sodium Perchlorate Complex

A new complex of a chiral monoaza-crown ether, [R-(-)-2-ethyl-N-benzyl-4,7,10,13-tetraoxa-1-azacyclopentadeceane) NaClO₄], has been prepared and studied by x-ray diffraction. The compound crystallizes in space group P2₁ with cell dimensions a = 9.480(1), b = 15.978(2), c = 15.816(2) Å, = 105.51(1)°, Z = 4. The final R value is 0.055 for 2711 observed reflections and 540 parameters. There are twomolecules in the asymmetric unit labelled A and B. The sodium ion is hexacoordinated. The average values for the Na–-O_eth (etheric) distances are 2.364(6), 2.317(7) Å and the Na–N distances are 2.679(6), 2.611(7) Å; the Na–-O(ClO₄) contacts are2.497(7) and 2.257(10) Å, for A and B, respectively.     

Antimicrobial activity studies of the metal complexes derived from substituted cyclobutane substituted thiazole Schiff base ligands

Two novel bidentate Schiff base ligands derived from 4-(1-methyl-1-mesitylcyclobutane-3-yl)-2-aminothiazole (LH) have been prepared and characterized by elemental analyses, i.r., ¹³C- and ¹H-n.m.r. spectra, u.v.–vis. and magnetic susceptibility measurements. The complexes are mononuclear. Antimicrobial activities of the ligands and their complexes have been tested: Bacillus megaterium DSM 32, Candida albicans FMC 17, Enterobacter aeroginosa CCM 2531, Escherichia coli ATCC 25922, Listeria monocytogenes SCOTTA, Micrococcus luteus LA 2971, Proteus vulgaris FMC 11, Pseudomonas aeruginosa DSM 50071, Saccharomyces cerevisiae FMC 16 and Staphylococcus aureus COWAN I. The thermal properties of the ligands and their complexes have been studied by t.g.a.