Engineering Commons^™

Modified Broyden’S Method For Accelerating Convergence In Self-Consistent Calculations, Duane D. Johnson

Duane D. Johnson

A modification to Broyden’s method for obtaining stable and computationally efficient convergence in self-consistent calculations is developed and discussed. The method incorporates the advantages of two schemes proposed by Srivastava and by Vanderbilt and Louie without any increase in complexity. Its improvement over their methods is discussed. The present method is compared with two other widely used convergence methods, simple mixing and Anderson’s method, for the case of the disordered binary alloy Ni0.35Fe0.65 on the verge of a magnetic instability and is shown to be much improved in stability and rate of convergence.

Polymer Science In Romania I: "Petru Poni" Institute Of Macromolecular Chemistry, Iasi, Romania, Otto Vogl, Cristofor I. Simionescu, Ioan I. Negulescu

Otto Vogl

No abstract provided.

U.S.-Japan Seminar: "Synthesis, Properties And Reactions Of Specialty Polymers", Otto Vogl, Hiroshi Sumitomo

Otto Vogl

No abstract provided.

31st International Congress Of Pure And Applied Chemistry, Sofia, Bulgaria,1987, Otto Vogl, Ivan Shopov, Ivan Panayotov

Otto Vogl

No abstract provided.

Polymer Science In Czechoslovakia Ii: Universities In The Czech Socialist Republic, Otto Vogl, Jaroslav Kralicek, Miroslav Schatz, Petr Vondracek

Otto Vogl

No abstract provided.

Equation Of State Of Dense Helium, Richard Alan Lesar

Richard Alan Lesar

Comparison between pressure-volume relations in helium at high pressures indicates that theoretical calculations based on gas-phase pair potentials are not adequate to explain recent x-ray experiments. Regardless of what potential is used, the gas-phase potentials give an equation of state that is much too stiff. It is shown that if the changes in the atomic wave functions induced by the high-pressure crystal environment are taken into account, then agreement between experimental and theoretical pressure-volume curves is greatly improved.

Segmentation-Based Image Coding In A Packet-Switched Network Environment, Sarah A. Rajala, Wonrae M. Lee

Sarah A. Rajala

In this paper, a segmentation-based image coding technique incorporating properties of the human visual system is presented. The approach taken in this research is to first segment an image into regions with spatial similarity and then to define an efficient method for encoding the segmented image data. Furthermore, specific attention is given in this paper to defining the requirements for using a segmentation-based image coder for video transmission over a packet-switched network.

Slip, Twinning, And Fracture At A Grain Boundary In The L12 Ordered Structure—Aς = 9 Tilt Boundary, Alexander H. King, M. H. Yoo

Alexander H. King

The role of interaction between slip dislocations and a Σ = 9 tilt boundary in localized microplastic deformation, cleavage, or intergranular fracture in the Li2 ordered structure has been analyzed by using the anisotropic elasticity theory of dislocations and fracture. Screw superpartials cross slip easily at the boundary onto the (1$\overline 1$1) and the (001) planes at low and high temperatures, respectively. Transmission of primary slip dislocations onto the conjugate slip system occurs with a certain degree of difficulty, which is eased by localized disordering. When the transmission is impeded, cleavage fracture on the ($\overline 1$11) plane is predicted to …

Iupac “Macro 87” In Merseburg (Gdr) Linking Tradition And Future In Polymer Science, Otto Vogl, Burkart Philipp

Otto Vogl

No abstract provided.

Comment On "Cluster-Size Evolution In A Coagulation- Fragmentation System", R. Dennis Vigil, Robert M. Ziff

R. Dennis Vigil

Sorensen, Zhang, and Taylor' have analyzed the stability of a system in which both binary coagulation and fragmentation occur.

Bulking Control With Ozonation In A Nutrient Removal Activated Sludge System, Johannes Van Leeuwen

Johannes van Leeuwen

The control of sludge bulking by ozonation was studied on four parallel pilot-scale (100 l/d) biological nutrient removal systems. Bulking was caused by filamentous organisms which typically occur in nutrient removal systems, i.e. Type 0092, Tpye 0041 and Microthrix parvicella. Continuous dosing of ozone, at 1; 2 and 4g O3/kg mixed liquor suspended solids (MLSS).d resulted in a diluted sludge volume index of about 50 ml/g less than the unozonated control. Ozonation was more effective in the sludge cycle than directly into the aeration basin. Nitrification-denitrification was not affected, not even at dosages of 30 g O3/kg MLSS.d. Biological phosphate …

New Universality Class For Gelation In A System With Particle Breakup, R. Dennis Vigil, Robert M. Ziff, Binglin Lu

R. Dennis Vigil

We introduce a model of coagulation with single-particle breakoft', described by the kernels K~1 ij and F1 a((j+1)b;& +(i+1)bj&). For a above a critical value a„the system either gels or reaches a steady-state size distribution, depending upon initial conditions. Below a„gelation always occurs. At a a„the scaling exponent i, which describes the large-size behavior of the steady-state size distribution, is 2 rather than the usual value &, indicating that this process belongs to a new universality class of gelation.

New High-Pressure Phases Of Ice, Pierfranco Demontis, Richard Alan Lesar, Michael L. Klein

Richard Alan Lesar

An ionic model has been used in conjunction with classical constant-pressure molecular-dynamics calculations to explore the properties of possible high-pressure phases of ice. Around 100 GPa, the model is found to convert from the symmetric hydrogen-bonded cuprite structure (ice X) to a fully ordered antifluorite structure. On heating, the new phase, ice XI, becomes a fast-ion proton conductor.

Character Of The Α-Β Phase Transition In Solid Oxygen, Richard Alan Lesar, R. D. Etters

Richard Alan Lesar

Properties of the α and β phases of solid O2 are calculated with a deformable-cell Monte Carlo method and the character of the associated phase transition is delineated. We find that the monoclinic α phase is stable at temperatures T≲18 K and in- and out-of-plane antiferromagnetic order is predicted that is in accord with experiment. The magnetic correlations appear to be long ranged. A phase transition into β-O2 occurs at T=17.75±0.2 K. It is first order with a calculated volume change ΔV=0.06±0.10 cm3/mole, and is accompanied by a magnetic transition into a highly dynamic quasihelical state with a correlation length …

Http://Www.Kingofsupplement.Com/Power-Testo-Blast/, Nina Navard

nina navard

Woman-Bikini-Body-Eating-Diet-700x700_1.Jpg, Harry Can

harry can

One Hundred Years Bayer Process For Alumina Production [In Arabic], Fathi Habashi

Fathi Habashi

Https://Forskolinslimfacts.Com/Slimlinic-Keto/, Konfu Seren

konfu seren

Http://Firmativabout.Com/Ketoviante/, Keithm Aderer

keithm aderer

Privy Farms Keto, Privyfarms Keto

privyfarms keto

"Power System Frequency Deviation Measurement Using An Electronic Bridge, Mukhtar Ahmad

Mukhtar Ahmad

No abstract provided.

Soil Compaction And Its Effect On Alfalfa In Zone Production Systems, Burl D. Meek, Eric A. Rechel, Lyle M. Carter, William R. Detar

William R DeTar

Alfalfa (Medicago sativa L.) was grown under two zone production systems (no harvest traffic) (i) preplan! compaction and (ii) no preplant compaction and compared to two systems where traffic was applied (i) to 100% of the area during each harvest and (ii) to lanes simulating the traffic a grower would apply during harvest. The experiment was done in a semiarid area under irrigation on a Wasco sandy loam (coarse-loamy, mixed, nonacid, thermic Xeric Torriorthent), which is easily compacted. Without traffic the soil settled to a bulk density of 1.6 to 1.70 Mg m~\ Traffic increased the bulk density to the …

Program Calculates Critical Properties, João F. Gomes

João F Gomes

No abstract provided.

Effects Of Chemical And Magnetic Disorder In Fe0.50mn0.50, Duane D. Johnson, F. J. Pinski, G. M. Stocks

Duane D. Johnson

We present the results of first‐principles calculations of the total energy and spin‐polarized electronic structure of disordered fcc Fe0.50Mn0.50. These self‐consistent calculations were performed using the Korringa–Kohn–Rostoker method and the coherent‐potential approximation (KKR‐CPA), using the local‐spin‐density approximation to treat exchange and correlation. We use a lattice constant of a=6.80 a.u.; information about stability can be inferred from calculated pressure and energy. The moments on the Fe and Mn sites are large but antiparallel to each other, resulting in a small net magnetization. A comparison of the electronic structure is made for fcc Fe, Mn, and FeMn in both the ferromagnetic …

Theoretical Study Of The Hyperfine Fields Of Ni And Fe In Fcc Ni,Fe, Alloys, H. Ebert, H. Winter, B. L. Gyorffy, Duane D. Johnson, F. J. Pinski

Duane D. Johnson

Using charge self-consistent cluster Korringa-Kohn-Rostoker coherent potential approximation (KKR-CPA) band-structure calculations, the authors have studied the hyperfine fields on both Ni and Fe sites in the NixFe1-x alloys. To elucidate the influence of relativistic effects the hyperfine matrix elements have been calculated nonrelativistically as well as completely relativistically The dependence of the hyperfine fields on the environment of a given site has been studied by performing calculations for various atomic configurations around that site. The results of the work are compared with other theoretical data and with experiment.

Thermodynamic Properties And Equation Of State Of Dense Fluid Nitrogen, J. Belak, R. D. Etters, Richard Alan Lesar

Richard Alan Lesar

Results of constant‐pressure Monte Carlo calculations on dense fluid nitrogen over a pressure range of 2 to 300 kbar and a temperature range of 300–3000 K are presented. From analytic fits to the calculated volumes, enthalpies and vibrational frequency shifts, a comprehensive set of thermodynamic quantities is derived, including: thermal expansivity, compressibility, specific heat, Grüneisen parameter, and speed of sound. Comparison of the theoretical results to experiment at room temperature shows very good agreement (within 0.3% in volume and 1% in speed of sound, for instance). Good agreement is also obtained with earlier simulation data. In agreement with experimental studies …

Electrically Erasable Programmable Logic Devices As An Aid For Teaching Digital Electronics, Nelson L. Buck, Kenneth A. Sudduth, Stuart J. Birrell

Stuart J. Birrell

Electrically erasable programmable logic devices (PLDs) are digital circuit components which can be programmed to perform complex logic functions. Agricultural engineering students designed circuits using PLDs and programmed and tested them as part of a class exercise in logic circuit design. The devices were erased at the end of the semester for use by the next class. Because the lab assignment required the students to master several new concepts at once, they experienced some initial difficulties; however, they enjoyed the assignment and learned the material well.

Pressure Interactions In Slotted Eave Inlets, Jay D. Harmon, K. A. Janni, L. D. Jacobson

Jay D. Harmon

Pressure Interactions in Slotted Eave Inlets Pressure Interactions in Slotted Eave Inlets ABSTRACT Afull scale physical model eave opening and baffled slot inlet system for a mechanically ventilated livestock building was tested to determine the effect of pressure differences and attic opening size on air flow rates. Pressure differences were varied between the eave, attic and room of the model. Flow rates through the attic and the room, and corresponding pressure differences were measured to calculate loss coefficients. Closed attic tests that prevented interactions between the inlet and attic were conducted to develop regression equations to predict the coefficient of …

Transport Processes In Random Arrays Of Cylinders. Ii. Viscous Flow, Ashok S. Sangani, C. Yao

Ashok S. Sangani

A numerical method is developed that takes into account the many-particle interactions in a rigorous manner to determine the effective thermal conductivity Km of a composite medium consisting of parallel circular cylinders of thermal conductivity ak suspended in a matrix of conductivity k. Numerical results for Km are presented for a wide range of a and o, the area fraction of the cylinders, after averaging over several computer-generated random arrays of cylinders. The results obtained via this exact method are compared with those of various approximate analytical methods to assess their utility in predicting Km.

Periodic Solutions For Three Sedimenting Spheres, Ashok S. Sangani, Russel E. Caflisch, Chjan Lim, Jonathan H. C. Luke

Ashok S. Sangani

Exact periodic solutions are found for the relative motion of three spheres sedimenting in a Stokes fluid. Nearby solutions are found to be nearly periodic for a long time. Existence of the exact periodic solutions is proved using the point-particle approximation and symmetry properties of Stokes equations. Numerical simulations for finitie-sized particles are performed using a method of multipole expansions.