[18-C-6H3O+]: an in-situ generated macrocyclic complex and an efficient, novel catalyst for synthesis of pyrano[2,3-c]pyrazole derivatives.

Synthesis of small aromatic heterocycles is of greater importance in the organic chemistry due to their vibrant applications in pharmaceuticals, agrochemicals and veterinary products. Pyranopyrazoles are one such class of heterocycles associated with numerous applications. Hence herein we report a multicomponent crown ether catalyzed, ultrasound irradiated methodology to make different functionalized pyranopyrazoles in a single step. This technique involves the in-situ generation of [18-C-6H3O+][OH-] complex, which in turn activates the aromatic aldehyde and aids in the facile nucleophilic addition.

Finite strain stress fields near the tip of an interface crack between a soft incompressible elastic material and a rigid substrate.

We present a numerical study of finite strain stress fields near the tip of an interface crack between a rigid substrate and an incompressible hyperelastic solid using the finite element method (FEM). The finite element (FE) simulations make use of a remeshing scheme to overcome mesh distortion. Analyses are carried out by assuming that the crack tip is either pinned, i.e., the elastic material is perfectly bonded (no slip) to the rigid substrate, or the crack lies on a frictionless interface. We focus on a material which hardens exponentially. To explore the effect of geometric constraint on the near tip stress fields, simulations are carried out under plane stress and plane strain conditions. For both the frictionless interface and the pinned crack under plane stress deformation, we found that the true stress field directly ahead of the crack tip is dominated by the normal opening stress and the crack face opens up smoothly. This is also true for an interface crack along a frictionless boundary in plane strain deformation. However, for a pinned interface crack under plane strain deformation, the true opening normal stress is found to be lower than the shear stress and the transverse normal stress. Also, the crack opening profile for a pinned crack under plane strain deformation is completely different from those seen in plane stress and in plane strain (frictionless interface). The crack face flips over and the tip angle is almost tangential to the interface. Our results suggest that interface friction can play a very important role in interfacial fracture of soft materials on hard substrates.

Autospec: computerized processing of the data output from a spectrophotometer in a biochemical laboratory.

Autospec was designed to acquire data output from a Beckman DU series 60 spectrophotometer and to process these data with an IBM or IBM-compatible computer. It functions in conjunction with the Beckman DU Data Capture and Lotus 1-2-3 softwares. Autospec automatically stores data produced by the spectrophotometer, determines standard curves and calculates unknown concentrations of the substance being assayed. The principal features of Autospec are simplicity of use, adaptability and flexibility, minimal intervention from the operator, standardized print-outs of all data in tabular and graphic forms, accuracy of computations, speed of operation, and ease of storage and back-up of data files.