Crystal structures of three substituted pentacyclo[5.4.0.02,6.03,10.05,9]undecanes

The crystal structures of three compounds formed via ultimate nucleophilic attack of unsaturated hydrocarbon fragments are reported. Geometries of the bis(vinyl)-, mono(vinyl), and bis(ethynyl)-substituted PCU species are unexceptional. The crystal structures are dictated by the availability of intermolecular hydrogen bonding.     

On the dynamics of turbulent vortical flow

Zusammenfassung Die Wirbelströmung in einer turbulenten kompressiblen Flüssigkeit wird behandelt. Die Bewegungsgleichungen werden durch die Vernachlässigung der kleineren Glieder vereinfacht. Die experimentellen Ergebnisse erlauben eine Fehlerrechnung für einen Fall. Ein wichtiger Schritt in der Vereinfachung ist die Voraussetzung, dass die Radialgradienten viel grösser sind als die Axialgradienten. Für die kräftigen Wirbel erwies sich diese Annahme sowohl durch die Erfahrung als auch aus den wesentlichen theoretischen Betrachtungen heraus als begründet. Die vereinfachten Gleichungen zeigen einige wichtige Aspekte der schnelldrehenden Strömungen und geben einen Anhaltspunkt für die ausführlicheren Studien.

---

Notation r radial co-ordinate - z axial co-ordinate - u, U, u radial velocity component, its time-mean value, and the turbulent perturbation to it - v, V, v tangential or swirl velocity component, etc. - w, W, w axial velocity component, etc. - p, P, p fluid pressure, etc. - ,R, fluid density, etc. - , , , numbers small with respect to unity - C, F, G, G ₀ constants of integration     

Magallanesine: an isoindolobenzazocine alkaloid

$\text{Berberis darwinii}$ Hook.(Berberidaceae) has yielded magallanesine ($\text{1}$), the first known isoindolobetizazocine alkaloid.     

Material symmetry and the evolution of anisotropies in a simple material—I. Change of reference configuration

Noll's rule is used to determine the structure of a material symmetry group written with respect to one reference configuration when the representation of the symmetry with respect to another configuration is the traditional material symmetry group associated with isotropy, transverse isotropy or orthotropy, and for an arbitrary deformation gradient relating the two configurations. It is shown that the former symmetry group can contain an orthogonal subgroup. It is determined whether this subgroup is that for isotropic, transversely isotropic, orthotropic, monoclinic, or triclinic response, and the preferred directions of the symmetry are determined.     

Alternative Inventory and Distribution Policies of a Food Manufacturer

Alternative distribution strategies for delivering to a retailer's regional depots are compared. These include supplying all the manufacturer's warehouses from the factory and allowing every possible lateral transshipment with partial stock rebalancing over different time periods. The principal alternative is to have a hierarchical system. Effects of making emergency transfers to deliberately delayed delivery vehicles are evaluated. A data stream of actual demands for a typical product is used and forecasts are made over different time periods for production planning, warehouse allocations and transshipments. The conclusions are examined for various production frequencies and levels of stock cover.     

Chemical repercussions of orbital interactions through bond and through space. Effect of remote substituents on the addition of nitrenes to bicyclic olefins

The reactivity of a series of bicyclic olefins with nitrenes is profoundly influenced by the nature of remote functional groups. There is a marked lack of reactivity for reactions with carboethoxynitrene as compared to phthalimidonitrene which is distinctly nucleophilic in character. An explanation for the reluctance to form aziridines is offered in terms of orbital interactions between the distant groups and the olefinic bond, making the latter remarkably electron deficient as evidenced by UV-photoelectron spectrosoopy. Because of the complexity of the spectra, identification of the Ip associated with the reactive π-centre was made by recourse to ab initio configuration interaction calculations for key members of the series.     

The mechanism of serine fluorodehydroxylation: 13C and 19F nmr studies

Competetive reaction pathwys responsible for the incomplete flourination of serine by SF₄ elucidated and inhibited.     

Single-root,real-basis-function method with correct branch-point structure for complex resonances energies

We present a new method for analytic continuation of real variational eigenvalues to calculate the complex energy of a collisional or photofragmentation resonance. The method is tested successfully against accurate quantum-mechanical results for model problems.