A hybrid computer program for rapidly solving flowing or static chemical kinetic problems involving many chemical species

A hybrid chemical kinetic computer program was assembled which provides a rapid solution to problems involving flowing or static, chemically reacting, gas mixtures. The computer program uses existing subroutines for problem setup, initialization, and preliminary calculations and incorporates a stiff ordinary differential equation solution technique. A number of check cases were recomputed with the hybrid program and the results were almost identical to those previously obtained. The computational time saving was demonstrated with a propane-oxygen-argon shock tube combustion problem involving 31 chemical species and 64 reactions. Information is presented to enable potential users to prepare an input data deck for the calculation of a problem

Enhancing productivity of water under variable climate

Crop productionMaizeClimateRainFamersDecision making

Enhancing productivity of water under variable climate

Irrigated farmingProductivityCrop productionMaizeSimulation modelsClimateForecasting

An optimality criterion for sizing members of heated structures with temperature constraints

A thermal optimality criterion is presented for sizing members of heated structures with multiple temperature constraints. The optimality criterion is similar to an existing optimality criterion for design of mechanically loaded structures with displacement constraints. Effectiveness of the thermal optimality criterion is assessed by applying it to one- and two-dimensional thermal problems where temperatures can be controlled by varying the material distribution in the structure. Results obtained from the optimality criterion agree within 2 percent with results from a closed-form solution and with results from a mathematical programming technique. The thermal optimality criterion augments existing optimality criteria for strength and stiffness related constraints and offers the possibility of extension of optimality techniques to sizing structures with combined thermal and mechanical loading

A Theory of Errors in Quantum Measurement

It is common to model random errors in a classical measurement by the normal (Gaussian) distribution, because of the central limit theorem. In the quantum theory, the analogous hypothesis is that the matrix elements of the error in an observable are distributed normally. We obtain the probability distribution this implies for the outcome of a measurement, exactly for the case of 2x2 matrices and in the steepest descent approximation in general. Due to the phenomenon of `level repulsion', the probability distributions obtained are quite different from the Gaussian.Comment: Based on talk at "Spacetime and Fundamental Interactions: Quantum Aspects" A conference to honor A. P. Balachandran's 65th Birthda

A single molecule switch based on two Pd nanocrystals linked by a conjugated dithiol

Tunneling spectroscopy measurements have been carried out on a single molecule device formed by two Pd nanocrystals (dia, $\sim$5 nm) electronically coupled by a conducting molecule, dimercaptodiphenylacetylene. The I-V data, obtained by positioning the tip over a nanocrystal electrode, exhibit negative differential resistance (NDR) on a background M-I-M characteristics. The NDR feature occurs at $\sim$0.67 V at 300 K and shifts to a higher bias of 1.93 V at 90 K. When the tip is held in the middle region of the device, a coulomb blockade region is observed ($\pm\sim$0.3 V).Comment: Accepted in Praman

A digital system for accurate time sector division of a spin stabilized vehicle

Digital system for accurate time sector division of spin stabilized vehicle as used on Pioneer space probe

Occurrence of Tachysurus dussumieri (Valenciennes) with incubating young ones off Mangalore

During the course of routine observations on the purse-seine landings at Mangalore, a catch of about 21t of catfish (Tachysnrus dussumieri) was noticed on March 1982. They were netted in a single haul by a purse seiner off the New Mangalore harbour at a depth of about 10 m. Earlier observations along the Mangalore coast show that this species spawns only once a year during the period from December to March with peak in February. The T. thalassinus releases the young ones from its mouth when they are smaller in size as compared to T. dussumieri which retains the young ones measuring upto 78 mm in their mouth. The species could hold in their oro-buccal cavities as high as 100 or even more developing eggs ensuring perhaps a high hatching and survival rate