Engineering Commons^™

Iupac 32nd International Congress On Macromolecules "Macro 88", Otto Vogl, Naohuki Koide, Tatsuki Kitayama, Koichi Hatada

Otto Vogl

No abstract provided.

Pig Vocalizations Under Selected Husbandry Practices, Hongwei Xin, James A. Deshazer, D. W. Leger

Hongwei Xin

Acoustical characteristics of vocalizations of sows, piglets, and nursery pigs under selected husbandry practices were analyzed with a digital signal processing system. The duration (D) and major energy-resonance frequency (P) for each call were determined as follows: a) processing of piglets (D = 0.81 s and f* = 3 700 Hz); b) food anticipation of breeding-gestation sows (2.50 s and 3 000 Hz); c) isolation of piglet (0.34 s and 500, 3 500 Hz); d) startling of nursery pigs (0.29 s and 900 Hz); e) sows in heat (3.07 s and 1 375 Hz); f) farrowing (0.10 s and 3 …

Random Sequential Adsorption Of Unoriented Rectangles Onto A Plane, R. Dennis Vigil, Robert M. Ziff

R. Dennis Vigil

Random sequential adsorption of nonoverlapping rectangles of arbitrary orientation onto a continuous plane was investigated by computer simulation. The approach to the jamming limit was found to obey Feder's law for a wide range of rectangle aspect ratios. The coverage fraction at the jamming limit was found to depend upon the aspect ratio of the adsorbed rectangles, with a maximum in the jamming coverage occurring at aspect ratios ~2.

Image Segmentation Using Human Visual System Properties With Applications In Image Compression, Heidi A. Peterson, Sarah A. Rajala, Edward J. Delp

Sarah A. Rajala

Many image compression techniques involve segmentation of a gray level image. With such techniques, information is extracted that describes the regions in the segmented image, and this information is then used to form a coded version of the image. In this paper we present a region-growing-based segmentation technique that incorporates human visual system properties, and describe the use of this technique in image compression. We also discuss the effect of requantizing a segmented image. Requantization of a segmented image is useful because it can lead to a reduction in the number of bits required to code the description of the …

Finite-Temperature Defect Properties From Free-Energy Minimization, Richard Alan Lesar, R. Najafabadi, D. J. Srolovitz

Richard Alan Lesar

We present two simple, but accurate, techniques for calculating the finite-temperature atomic structure and free energy of any solid defect (point or extended). The finite-temperature equilibrium atomic structure and thermodynamic properties of defects in solids are obtained self-consistently by minimizing the rree energy of the solid with respect to the coordinates of the atoms. Application of the two methods to a perfect crystal and one with a vacancy show that both methods yield excellent agreement with Monte Carlo calculations for temperatures up to at least 75% of the melting point.

High-Density Structures And Phase Transition In An Ionic Model Of H 2 O Ice, P. Demontis, M. L. Klein, Richard Alan Lesar

Richard Alan Lesar

A self-consistent ionic model of water (protons and O 2- ions) has been used to explore the low-temperature, high-pressure properties of ice. Interionic interactions were calculated with the electron-gas model, and the self-consistent changes in the electronic structure of the oxide ions were modeled with Watson spheres. A phase transition is predicted at about 330 GPa from the observed, low-pressure, symmetric hydrogen-bonded cuprite structure to a fully ordered antifluorite structure. The transition pressure is higher than the 100-GPa estimate obtained from a molecular-dynamics study [Phys. Rev. Lett. 60, 2284 (1988)] that employed more approximate potentials.

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Measuring The Nanomechanical Properties And Surface Forces Of Materials Using An Atomic Force Microscope, Nancy Burnham, Richard Colton

Nancy A. Burnham

An atomic force microscope(AFM) has been configured so that it measures the force between a tip mounted on a cantilever beam and a sample surface as a function of the tip–surface separation. This allows the AFM to study both the nanomechanical properties of the sample and the forces associated with the tip–surface interaction. More specifically, the AFM can measure the elastic and plastic behavior and hardness via nanoindentation,van der Waals forces, and the adhesion of thin‐film and bulk materials with unprecedented force and spatial resolution. The force resolution is currently 1 nanonewton, and the depth resolution is 0.02 nm. Additionally, …

Nife Invar Alloys: Theoretical Insights Into The Underlying Mechanisms Responsible For Their Physical Properties, Duane D. Johnson, F. J. Pinski, J. B. Staunton, B. L. Gyorffy, G. M. Stocks

Duane D. Johnson

What are the "driving forces" responsible for various physical properties of alloys? What causes alloy systems to order chemically and/or magnetically? To answer these questions, we have been using a quantum mechanical (QM) method to calculate cohesive energies, magnetic properties, and thermodynamic phase instability of alloys. This scheme directly incorporates the inherent disorder of the high-temperature solid solution and in this sense goes beyond traditional "band theory." Although approximations have been made at various steps in the thermodynamical averaging, and in the QM treatment of the electrons, adjustable parameters have not been used. Recently, for FCC NiFe (INVAR) alloys, we …

Progress In The Development Of Hemp Protection Standards For C3i Facilities, George H. Baker, Clinton R. Gordon

George H Baker

DoD is involved in EMP standards development efforts which culminate 25 years of research. This paper previews an EMP protection standard for fixed, ground-based communication facilities. The standard uses a low-risk hardening approach which depends on an electromagnetic barrier comprised of a conducting shield to prevent harmful transients from reaching communication electronics. The standard is the first of its kind and is being instituted as MIL-STD-188-125.

Ozonation For Non-Filamentous Bulking Control In An Activated Sludge Plant Fuel Synthesis Waste Transfer, Johannes Van Leeuwen

Johannes van Leeuwen

A zero discharge mode of operation at the South African fuel synthesis plants necessitates the infinite recycle of treated industrial waste water. The treatment process incorporates activated sludge units in which non-filamentous bulking and carry-over of solids often occurs. The use of ozone for the control of this non-filamentous binding was investigated on a 33 l/d small pilot-scale plant. An ozone dosage of 1 g per kg mixed liquor suspended solids per day could reduce the diluted sludge volume index from an average of 125 to about 70 ml/g mainly by preventing zoogleal growths, the main contributor to the non-filamentous …

Pitch Of Complex Tones With Many High‐Order Harmonics, Adrianus J. M. Houtsma, J. Smurzynski

Jacek Smurzynski

Changes In Infiltration Under Alfalfa As Influenced By Time And Wheel Traffic, Burl D. Meek, Eric A. Rechel, Lyle M. Carter, William R. Detar

William R DeTar

Infiltration rates were measured for alfalfa, (Medicago saliva L., cv. WL514) subjected to treatments where wheel traffic was varied in terms of area covered and time of application on a Wasco sandy loam (coarse-loamy, mixed, nonacid thermic Xeric Torriorthent). Traffic treatments were (i) No-traffic, (ii) Preplant, MO Repeated, and (iv) traffic similar to what a grower would apply. Infiltration rates increased for all treatments, with increases being 240% for treatments without harvest traffic and 140% for treatments with harvest traffic Increases in infiltration were related to decreases in stand density. Slight packing (traffic) applied before the soil was flood-irrigated in …

Infiltration Function From Furrow Stream Advance, William R. Detar

William R DeTar

Average infiltration rates for large land areas can be quickly determined using a new procedure for obtaining the coefficients of the Kostiakov equation. By introducing the concept of the average opportunity time it is possible to plot the infiltration function directly from tabulated data. This modification of the volume-balance method is a staightforward one, which is easy to understand and learn.

An Expert System For Tractor Selection, Steven A. Freeman, P. D. Ayers

Steven A. Freeman

A user friendly expert system to assist the farmer in tractor selection was developed based on the evaluation procedure developed by Rider et al. (1979). This evaluation procedure utilizes Nebraska Tractor Test data from 1980 to 1986 along with information provided by the farmer to make selection decisions. The expert system provides the farmer with a list of tractors that are best suited for a specific operation. However, it is only designed to aid the farmer in the tractor selection process, not to provide a definite solution.

The Planar Singular Solutions Of Stokes And Laplace Equations And Their Application To Transport Processes Near Porous Surfaces, Ashok S. Sangani, S. Behl

Ashok S. Sangani

The planar singular solutions of Stokes and Laplace equations are derived and applied to a number of transport problems associated with porous surfaces. The velocity, pressure, concentration, and temperature slip coefficients are determined exactly for the semi-infinite periodic arrays of spheres and these are compared with the predictions of two approximate continuum theories formulated by Brinkman [Appl. Sci. Res. Sect. A I, 27 (1947)] and Chang and Acrivos [J. Appl. Phys. 59, 375 (1986)] to assess the utility of such theories in accurately predicting various overall properties related to the porous surfaces. It is found that in general these theories …

Bubble Break-Up In Air-Sparged Bioreactors, Michael Prince, J. Walters, H. Blanch

Michael J. Prince

No abstract provided.

Thermal And Rheological Properties Of A Liquid-Crystalline Polyurethane, William Macknight, Peter J. Stenhouse, Enrique M. Valles, Simon W. Kantor

William MacKnight