Engineering Commons^™

Ground- And Excited-State Properties Of Solid Argon Under Pressure, Richard Alan Lesar

Richard Alan Lesar

A self-consistent perturbation model for calculating the ground- and excited-state electronic properties of molecular and rare-gas crystals is presented. A tight-binding approximation is used, in which the effects of the crystal potential, calculated with local-density functionals, are included as a perturbation on the molecules (or atoms). The molecular (atomic) wave functions are then computed from standard Hartree-Fock theory. For the case of solid argon under pressure, a decrease in atomic volume causes a gain in free energy, which is partially balanced by the energy required to compress the atom. Calculated exciton energies for Ar disagree by only 2.5% with experimental …

Polarizability And Quadrupole Moment Of A Hydrogen Molecule In A Spheroidal Box, Richard Alan Lesar, D. R. Herschbach

Richard Alan Lesar

The polarizability and quadrupole moment of a hydrogen molecule enclosed within an infinite-walled spheroidal box are calculated as functions of the hox size, for a range corresponding to nominal pressures up to lo5 kbar. A five-term James and Coolidge variational wave function is employed and the Kirkwood approximation is used for the polarizability. Comparison is made with similar calculations for the H2+ molecule-ion and the II atom, and also with recent density-functional calculations. The box model proves to greatly exaggerate the compression of the H2 bond with pressure but nonetheless yields a realistic correlation of vibrational frequency with internuclear distance. …

Centers Of Polymer Research; Polymer Science In Northeastern Japan, Otto Vogl, T. Yamaguchi

Otto Vogl

No abstract provided.

Centers Of Polymer Research; Polymer Science In Hokkaido, Japan, Otto Vogl, J. Sohma

Otto Vogl

No abstract provided.

Turbine Blade Image Processing System, Neal S. Page, Wesley E. Snyder, Sarah A. Rajala

Sarah A. Rajala

A vision system has been developed at North Carolina State University to identify the orientation and three dimensional location of steam turbine blades that are stacked in an industrial A-frame cart. The system uses a controlled light source for structured illumination and a single camera to extract the information required by the image processing software to calculate the position and orientation of a turbine blade in real time.

Regrowth And Yield Of Alfalfa As Influenced By Wheel Traffic, Burl D. Meek, Lyle M. Carter, Richard H. Garber, Eric A. Rechel, William R. Detar

William R DeTar

Wheel traffic from equipment used to harvest alfalfa reduces yields because of crown damage and soil compaction. As much as 70% of the soil surface may receive wheel traffic during a single harvest.

Travel Time For Chemicals In An Irrigation System, William R. Detar

William R DeTar

When a chemical is injected into an irrigation system, the length of time it takes to reach the end of the longest path can have a large effect on the uniformity of distribution of the chemical in the field. In trickle irrigation systems, the time to travel this path is also the minimum time before the end of the cycle at which system maintenance chemicals should be injected. In the case where wastewater is being applied to land through an irrigation system or where an injected chemical would cause damage to the piping if it were to remain in the …

Trickle Irrigation Vs. No-Irrigation Of Five Horticultural Crops In Pennsylvania, William R. Detar, David F. Kibler, D. W. Grenoble, R. Daniels, R. H. Cole

William R DeTar

IN humid regions, the question of whether one should irrigate often overshadows problems such as selecting the proper system or scheduling procedure. To show whether it pays to irrigate by running irrigation experiments in the field is a long, expensive process. It would take perhaps five to ten years to determine significant relationships. The approach used in this project was to set up a computer model relating crop yields to weather data and moisture stress, and then verify the model at a few points using field experiments. This first report on the project includes only the field procedures and yields.

The Removal Of Fluorine From Wet Process Phosphoric Acid, Fathi Habashi

Fathi Habashi

Fluorine (and silicon) can be removed from technical phosphoric acid (30% P205) and recovered quantitatively as a by-product by adding a sodium or a potassium salt preferably the carbonate and boiling for a few minutes. The corresponding fluorosilicate precipitate, e.g. 2Na+ + SiF6- → Na2SiF6 can be separated by filtration. If this procedure is followed, no precipitation will take place in the evaporators during concentration of acid to 40% P2O5.

Density‐Functional Theory For Solid Nitrogen And Carbon Dioxide At High Pressure, Richard Alan Lesar, R. G. Gordon

Richard Alan Lesar

Structural properties of solid N2 and CO2 under pressure have been studied with a recently reported theory. The model allows for calculation of the structure and dissociation energy of molecular crystals, using no empirical parameters where dispersion energy is included as a sum of the pair interactions. Comparison with available low temperature experimental results shows good agreement with average errors in lattice constants of about 1% and in lattice energies of about 6%. Calculations were performed on nitrogen in a number of structures, including the experimentally observed P a3 (α), P42/m n m (γ), P63/m m c (β), and P …

Equation Of State Of Fluid Nh3 From P-V-T And Ultrasound Measurements To 12 Kbar, R. L. Mills, D. H. Lienbenberg, Richard Alan Lesar, Ph. Pruzan

Richard Alan Lesar

A piston-cylinder apparatus was used to measure the pressure, volume, temperature, and ultrasonic velocity (P,V,T,u) of fluid NH3 from 195 to 320 K at pressures up to 12 kbar. Over 1200 sets of P-V-T-u and P-V-T data were fitted to a Tait-type equation of state (EOS) by non-linear least-squares minimization. With quadratic terms in T for the two fitted parameters, the rms deviation is ± 0.2% in V and ± 0.9% in u, which is comparable to the experimental error. The simple Tait EOS is useful over the entire fluid range between the vaporization and melting curves up to T …

An Improved Rotary Singulator, Burford J. Furman, J. M. Henderson

Burford J. Furman

A new operating approach for a previously existing rotary singulator was developed which improves the versatility of the device. This was accomplished by the implementation of a modular mechanism that performed the basic functions of agitation, gating, pocket formation, and exit, all inherent in this type of singulation device.

Structure And Morphology Of Segmented Polyurethanes: 2. Influence Of Reactant Incompatibility, William Macknight, C. H. Y. Chen, R. M. Briber, E. L. Thomas, M. Xu

William MacKnight

A Differential Scanning Calorimetry Method For Determining Strain-Induced Crystallization In Elastomeric Fibers, William Macknight, R. E. Lyon, R. J. Farris

William MacKnight

No abstract provided.

Phase Behavior In Copolymer Blends: Poly(2,6-Dimethyl-1,4-Phenylene Oxide) And Halogen-Substituted Styrene Copolymers, William Macknight, Gerrit Ten Brinke, F. E. Karasz

William MacKnight

Dynamic Mechanical And Dielectric Properties Of An Epoxy Resin During Cure, William Macknight, Walter X. Zukas, N. S. Schneider

William MacKnight

No abstract provided.

Compatibility Of Some Fluorosubstituted Styrene Polymers And Copolymers In Blends With Poly(2,6-Dimethyl-1,4-Phenylene Oxide) And With Polystyrene, William Macknight, Radivoje Vukovic, F. E. Karasz

William MacKnight

No abstract provided.

Structure And Morphology Of Segmented Polyurethanes: 1. Influence Of Incompatibility On Hard-Segment Sequence Length, William Macknight, M. Xu, C. H. Y. Chen, E. L. Thomas

William MacKnight

No abstract provided.

Compatibility Of Poly(P-Fluorostyrene-Co-O-Fluorostyrene) With Poly(2,6-Dimethyl-1,4-Phenylene Oxide) And Polystyrene, William Macknight, R. Vukovic, F. E. Karasz

William MacKnight

No abstract provided.

Evidence For Critical Double Points In Blends Of Polystyrene And Poly(O-Chlorostyrene), William Macknight, Sherrie L. Zacharius, Gerrit Ten Brinke, F. E. Karasz

William MacKnight

Compatibility Of Poly(2.6-Dimethyl-1,4-Phenylene Oxide)/Poly(Fluorostyrene-Co-Chlorostyrene) Blends, William Macknight, Radivoje Vukovic, Vjera Kuresevic, F. E. Karasz, Nikola Segudovic

William MacKnight

No abstract provided.