Showing papers by "Michigan Technological University published in 1982"

Study of the electronic structure of twelve alkali halide crystals

Abstract: In this manuscript we use nonrelativistic self-consistent Hartree-Fock theory to compute the electronic structure of twelve alkali halides. Only compounds containing Cs or I are excluded because the author believes that relativistic effects should be included for such compounds. Correlation effects are included by our previously developed methods. The calculations are performed to compare to photoemission-type data. Extensive comparisons to such data are made. In this calculation a new version of the local-orbitals theory is used, and the bands are computed with the use of a modern development of the mixed-basis method.

Large deflections of cantilever beams of non-linear materials of the Ludwick type subjected to an end moment

Abstract: This paper deals with the large deflections (finite) of thin cantilever beams of non-linear materials of the Ludwick type. The beam is subjected to an end constant moment. Large deflections of beams induce geometrical non-linearity. Therefore, in formulating the analysis, the exact expression of the curvature is used in the Euler-Bernoulli law. A closed-form solution is presented for the resulting second-order non-linear differential equation. This solution is compared to previous results assuming linear elastic materials. Deflections at the free end of beams of aluminum alloy and annealed copper are obtained.

Fate of specific pollutants during wet oxidation and ozonation. Where do the pollutants wind up in oxidational purification processes? Here is a well documented experimental study

Abstract: The ability of wet oxidation and ozonation to destroy five typical priority pollutants (phenol, 2-chlorophenol, 1,2-dichloroethane, 4-nitrophenol, and dimethylphthalate) is reported. Particular attention has been paid to interpreting the batch kinetic data, exploring the influence of initial pH on ozonation and identifying and measuring the low-molecular weight organic acids produced. 28 references, 16 figures, 6 tables. (JMT)

On the theory of stress-assisted diffusion, II

Abstract: Similarity and general steady-state solutions of a recently developed strees-assisted diffusion theory are derived. General transient solutions are obtained analytically for certain classes of stress distributions. For general stress distributions a perturbation method is employed to produce transient solutions. Under appropriate conditions the derived solutions are reduced to previous formulae that have unsystematically appeared in the literature. Examples of interesting crack problems involving stress singularities as well as the elimination of singularities are considered. An equilibrium solution is utilized together with a straightforward physical argument to produce rationally two empirical formulae previously proposed in the literature to model embrittlement and stress corrosion cracking phenomena. This solution is further used to model embrittlement and stress corrosion cracking data more successfully than previous attempts. An appendix on certain preliminary elastodiffusive fracture criteria is given.

138-kV, Six-Phase Transmission System: Fault Analysis

Abstract: In the past decade, transmission planners and researchers have been keenly investigating the feasibility of six-phase concept as a planning alternative. The concept, if proved feasible, would alleviate the problem of acquiring additional rights-of-way to meet the increase in electric power and energy demand. Allegheny Power System (APS) has been investigating the conversion of some of their 138-kV three-phase double- circuit lines to 138-kV six-phase lines. The latter is an alternate option to 230-kV three-phase upgrading of the line.

Small particles in plumes of Mount St. Helens

Abstract: Particles in the size range 0.1-25 microns were sampled by aircraft carrying a quartz crystal microcascade in the Mount St. Helens plume on three dates in August and September 1980. Two of the sampling dates represented 'typical' emissions of the volcano between plinian eruptions. One sampling flight was made 1-4 hours before the small plinian eruption of August 7, 1980 when the plume had become discontinuous and visibly darker. The plume sampled on August 7, before the eruption, contained mainly approximately 2-micron diameter silicic glass particles, fragments of the Mount St. Helens magma. The typical plumes sampled on September 22 and August 6 had much smaller concentrations of particles, trimodal size distributions with peaks at 10, 0.4, and 0.1 microns. The particles were largely nonsilicate and apparently represented Cu-Zn oxide (10 micron peak), Al sulfate, chloride, and oxide, and sulfuric acid (smallest size peak).

The effect of mold precession on channel and macro-segregation in ammonium chloride-water analog castings

Abstract: Analog castings of two geometrical forms have been studied to observe the effect of continuously changing the direction of gravitational force on patterns of segregation. Molds of slab form, cooled on one side, and of cylindrical form, cooled at the base, were rotated axially at rates from 0 to 10 rpm with the axis of rotation tilted from 0 to 30 deg to the vertical: the development of “A” channel segregation in the former and of “freckel” channels in the latter were recorded photographically, while changes in bulk liquid concentration were followed over time periods up to one hour. It was observed that changing the direction of gravitation, slowly and continuously, markedly retarded or eliminated the formation of segregation channels and that consequent macrosegregation was also retarded and reduced. The application of the principle to foundry practice is discussed.

On the applicability of CNDO indices for the prediction of chemical reactivity

Abstract: A series of CNDO/2 molecular orbital properties were evaluated to determine their utility in parameterizing chemical reactivities. Some of these indices were used previously for only Π electron methods and were extended here to include the σ framework. Theoretical rationales were given for this extension to the semi-empirical all valence electron methods. Four systems, the aromatic hydrocarbons, the benzene derivatives, the substituted benzoic acids, and the substituted phenyl amines, were studied to test how well these indices can parameterize chemical reactivities. This study focused on reactions involving both σ and π electrons where the reactive site is not necessarily on the aromatic framework. For the nonplanar and heteropolar systems, these indices performed as well as the Huckel method did for the classical aromatics. These CNDO indices should perform effectively in multivariable regressions to parameterize the reactivities for more complicated problems such as those encountered in quantitative structure activity relationships of drugs.

Multiple funnel flake aligner for making a loosely felted mat of aligned wood flakes

Abstract: Apparatus for forming a loosely felted mat of thin elongated wood flakes with said flakes being aligned in mutually parallel relation. The apparatus includes a mat supporting surface, a hopper for holding a quantity of wood flakes, and a funnel assembly for receiving wood flakes from the hopper and for causing the flakes to be aligned in substantially parallel side-by-side relation as they are deposited on the supporting surface. The funnel assembly includes a plurality of funnels positioned in adjacent side-by-side relation, the funnels each including inclined walls having lower edges defining an elongated narrow opening adjacent the supporting surface and upper edges defining an opening wider than said narrow opening and for receiving wood flakes from the hopper. The narrow openings of the funnels are parallel and distribute the flakes uniformly across the supporting surface.

Molded wood particle pallet having increased bending strength

Abstract: Palette moulee formee de maniere unitaire (10) comprenant des particules de bois liees ensemble par un liant polymerise dans une relation comprimee et formant un pont (12) possedant une surface superieure supportant une charge, et une pluralite de canaux allonges, espaces et sensiblement paralleles (14) soutenant le pont. Formed unitarily molded pallet (10) comprising wood particles bonded together by a polymeric binder in a compressed relationship and forming a bridge (12) having an upper surface supporting a load, and a plurality of elongated channels, spaced apart and substantially parallel (14) supporting the bridge. Les canaux s'etendent d'une zone adjacente a un bord de la palette a une zone adjacente au bord oppose. The channels extend from an area adjacent to an edge of the pallet to a region adjacent to the opposite edge. Chaque canal comprend des parois laterales de canal espacees (24) s'etendant vers le bas depuis le pont et se terminant par une paroi plane de fond (16) parallele au pont. Each channel comprises side walls spaced channel (24) extending downwardly from the bridge and ending with a flat bottom wall (16) parallel to the bridge. Les parois laterales sont reliees ensemble a leurs bords inferieurs a la paroi de fond. The sidewalls are connected together at their lower edges to the bottom wall. Le pont et les canaux allonges sont formes en deposant une natte (34) feutree de maniere lâche de particules de bois dans une presse, la natte comprenant des ecailles de bois melangees avec un liant et les ecailles de bois etant minces et generalement planes et etant disposees dans une relation feutree de maniere a etre disposees sur des plans essentiellement horizontaux en relation d'intercalation, et en comprimant la natte. The bridge and the elongated channels are formed by depositing a mat (34) loosely felted wood particles in a press, the mat comprising wood flakes mixed with a binder and scales of wood being thin and being generally planar and arranged in an intimate relationship to be disposed on substantially horizontal planes in relation intercalation, and compressing the mat.

Modeling and Interpreting Oxygen Transfer Data

Abstract: Recommendations for modeling, parameter estimation, and experimental design in unsteady state clean water aeration tests are presented. The basic model for both surface and subsurface aeration systems is the exponential form of the first order mass transfer equation. A nonlinear least squares regression procedure is recommended for estimating the oxygen transfer coefficient and equilibrium saturation concentration. Techniques for selecting the number and spacing of data values and for assessing model adequacy are suggested. Methods for applying clean water test results to field water conditions are described and an example problem is presented.

The Influence of Grain Boundary Phosphorus Concentration on Liquid Metal and Hydrogen Embrittlement of Monel 400

Abstract: The susceptibility of Monel 400® to embrittlement by mercury and by hydrogen was measured as affected by thermal treatment. Specimens were annealed at 900°C and either quenched or furnace cooled. Auger analysis revealed phosphorus segregated to the grain boundaries; furnace cooling causes the boundary concentration to be about twice that of the quenched material. Tensile tests were conducted with specimens (1) in air, (2) coated with mercury, or (3) cathodically precharged with hydrogen. Fractures in air were completely ductile, and ductility was not affected by thermal treatment. Fractures of mercury-coated and hydrogen-charged samples were brittle and intergranular; elongation to fracture increased significantly with increasing concentration of grain boundary phosphorus. The results are discussed in terms of additive and interactive mechanisms.

Molded wood particle products including integrally joined intersecting members

Abstract: Un produit moule est forme a partir de lamelles de bois melangees avec un liant et un premier organe allonge forme a partir de lamelles allongees de bois comprimees et liees avec un liant, les lamelles de bois ayant une direction du grain s'etendant generalement parallelement a l'axe longitudinal des lamelles, ces dernieres etant generalement orientees en alignement avec l'axe longitudinal du premier organe allonge Un second organe allonge intersecte le premier organe allonge et est assemble de maniere solidaire avec ce dernier Le second organe allonge est egalement forme avec des lamelles allongees de bois, comprimees et liees avec un liant, les lamelles de bois etant generalement orientees en alignement avec l'axe longitudinal du second organe allonge Les lamelles de bois du second organe allonge intersectent et s'entremelent avec les lamelles de bois du premier organe allonge de maniere a former un joint moule solidaire entre le premier organe allonge et le second organe allonge

Fracture in Equiaxed Two Phase Alloys: Part I. Fracture in Alloys with Isolated Elastic Particles

Abstract: Fracture in equiaxed two phase alloys containing isolated elastic particles has been analyzed from the viewpoint of a recently proposed model for fracture initiation and propagation in such materials. This model predicts fracture toughness parameters in terms of the microstructural geometry, relative phase volume fractions, and tensile properties of the materials. Predictions of the model are tested experimentally for two phase Co-CoAl alloys over a wide range of compositions, and the results indicate good agreement between predicted and observed fracture toughnesses.

Elongate structural members comprised of composite wood material

Abstract: An elongate structural member has a longitudinal axis and is comprised of a plurality of elongate panels having lateral edges, the panels being arranged to form an elongate central cavity with lateral edges of adjacent panels being fixedly joined together. The elongate panels are each comprised of a plurality of wood particles intermixed with a suitable binder and compressed to form a densified product. A rigid foam material is provided filling at least a portion of the elongate central cavity for reinforcing the elongate structure, the rigid foam material also being bonded to the inwardly facing surfaces to further reinforce the elongate structure.