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Comment On The Nature Of The Disaccommodation In Hcp Co-C Alloys, J. Keiser, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

Activation Volumes Of Carbon Diffusion In Fcc Iron-Nickel Alloys, J. Keiser, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

The Dis accommodation technique was used to determine the activation volume of carbon diffusion, ΔV, in six fcc iron-nickel alloys. Measurements were made at temperatures ranging from 68 to 90 °C and pressures up to 6 kbar on samples having a nickel content between 31 and 63 at.%. A maximum activation volume of 3.9 cm3/mole was found at 34 at.% nickel. The compositional dependence of ΔV is satisfactorily reproduced by a magnetic-energy continuum model in which it is assumed that the activation free energy of diffusion is essentially ferromagnetic in origin. © 1972 The American Physical Society.

Pbo Transformation Induced By Water, Charles A. Sorrell

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

Proceedings Of The 2nd International Symposium On Lower-Cost Housing Problems, Oktay Ural

International Symposia on Low Cost Housing Problems

To protect and improve the total human environment is a major concern of all the nations of the world. This is well noted in the recent activities of the United Nations. The provision of decent homes for every family of our world is an integral part of the human environment. It is this belief which generated the initial interest for the planning of the International Symposia on Lower-Cost Housing Problems.

The purpose of the Second International Symposium is many sided: to generate concern on the housing problems around the world as they exist today; to gather people who share mutual …

An Application Of Bubble Shape Theory To The Determination Of Air Transfer Through Adsorbed Surface Films, Robert A. Medrow

Mechanical and Aerospace Engineering Faculty Research & Creative Works

No abstract provided.

Thomson's E/M Experiment Revisited, Michael Glascock, Don M. Sparlin

Physics Faculty Research & Creative Works

The objective of this experiment is to familiarize the student with the impulse theorem, electron dynamics, and magnetic field contours. He is challenged to obtain accurate as well as precise measurements with suboptimum apparatus through correct analysis. He also investigates the influence of various systematic errors using model calculations on a small computer. © 1972, American Association of Physics Teachers. All rights reserved.

An Inexpensive Electrical Vacuum Feedthrough, D. R. Kastelein, Richard A. Anderson, Kaare J. Nygaard

Physics Faculty Research & Creative Works

No abstract provided.

A Study Of Phosphorus Adsorption And Desorption Kinetics On Silicon (111) Surfaces, L. E. Davis, L. L. Levenson, J. J. Melles

Physics Faculty Research & Creative Works

Low energy electron diffraction (LEED) and Auger electron spectroscopy (AES) methods were used to characterize the (111) surface of Si wafers before and after the deposition of P2 molecules. Before deposition, the well-known Si(111)-7 LEED pattern was easily obtained by thermal cleaning at 1200 °C. Cleaning was done by electron bombardment in a vacuum chamber with a base pressure of ∼ 10-10 Torr. After cleaning, AES showed that about 10-2 atomic layer of carbon was the only surface contaminant. The sensitivity of our cylindrical AES apparatus for phosphorus was about 10-3 atomic layer. We found that ∼5x10-2 atomic layer of …

A Correction To Classical Homogeneous Nucleation Theory For Polar Molecules Exhibiting An Electric Double Layer At The Liquid Surface, Daniel R. White, James L. Kassner

Physics Faculty Research & Creative Works

An oriented dipole surface layer is added to the classical liquid drop model of nucleation to account for the surface behavior of substances having polar nonsymmetrical molecules. The preliminary treatment of the change in free energy as given by Abraham is modified to include Fletcher's exponential decay of the degree of orientation. An additional correction for the excess binding energy due to the presence of a foreign molecule in the prenucleation cluster is included to account for the inflections observed in the experimental results of Allen and Kassner. The resulting free energy of formation is combined with the kinetic treatment …

Excited-Ion Lifetimes Using Penning-Ionizing Collisions, William F. Parks, Laird D. Schearer

Physics Faculty Research & Creative Works

We show that in the Penning-ionizing collision He(23S1)+X→He(11S0)+(X+)*+e the precession of the Hem spin at its Larmor frequency forces the J polarization of the Penning ion to rotate at the same frequency but shifted in phase. The tangent of the phase shift is proportional to the lifetime of the ionic state and presents a unique method for measuring excited-ion lifetimes. © 1972 The American Physical Society.

Application Of The Weiss Molecular Field Theory To The B‐Site Spinel, W. E. Holland, Harry A. Brown

Physics Faculty Research & Creative Works

A molecular field treatment of the B‐site spinel was used to determine the ordering temperatures and the asymptotic Curie temperature in terms of the exchange integrals. The theory was developed from a 16‐sublattice model and took into account interactions between an atom and its nearest to fourth‐nearest neighbors. Experimental values of the ordering temperatures and the asymptotic Curie temperature were then used to determine the exchange integrals for the systems Hg1−xCdx Cr2 S4, CdCr2S4(1−y)Se4y, and Zn1−xCdxCr2Se4. Copyright © 1972 WILEY‐VCH Verlag GmbH & Co. KGaA

The Plasma Polymerization Of Vinyl Monomers. I. The Design, Construction, And Operation Of An Inductively Coupled Plasma Generator And Preliminary Studies With Nine Monomers, L. F. Thompson, Kenneth G. Mayhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

An apparatus was constructed which would allow vinyl‐type monomers (and others) to polymerize at ambient temperatures in the presence of an inductively coupled RF field. The details of the construction of the system are reported along with preliminary results obtained from nine monomers: styrene, methylvinyldichlorosilane, vinyl acetate, acrylonitrile, vinyl fluoride, 1,1‐difluoroethylene, vinyl chloride, ethylene, and 1,3‐butadiene. Copyright © 1972 John Wiley & Sons, Inc.

Characterization Of Poly(Methyl Methacrylate) From Radiation‐Induced Polymerization In The Presence Of A Kaolin Clay Substrate, J. J. Beeson, Kenneth G. Mayhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Two types of polymer are formed in the radiation‐initiated polymerization of methyl methacrylate (MMA)–kaolin clay complexes. Homopolymer can be extracted from the complex by the use of organic solvents. Inserted polymer must be removed by dissolution of the polymer–clay complex with hydrofluoric acid. The polymers formed show no differences in structure (as determined by infrared analysis), had high molecular weights (1–5 x 106), and had similar molecular weight distributions (as determined by GPC). The molecular weights of the homopolymer increased as temperature increased (25°–75°C), and dose rate decreased (24.9–7.35 rads/sec). The isotacticity of the polymers when compared to irradiated bulk …

Study Of Cold-Formed Steel Structural Members Made Of Thick Sheets And Plates, William M. Mckinney, Victor A. S. Liu

CCFSS Library (1939 - present)

INTRODUCTION In steel design, the Specification for the Design of Cold-Formed Steel Structural Members l issued by the American Iron and Steel Institute has long been used for structural members cold-formed to shape from steel sheet or strip used for load-carrying purposes in buildings and other thin walled steel structures. Even though no thickness limitation was included in previous editions of the Specification, 2,3, the thickness of material used in the cold-formed steel construction was often limited to about 1/4 inch because the maximum thickness of steels used under all ASTM Specifications listed in Section 1.2 of the AISI Specification …

Column Research Council Proceedings, Fritz Engineering Foundation

CCFSS Library (1939 - present)

These Proceedings are a record of the Annual Meeting containing the abstracts of the reports presented and the transcription of our panel discussion.

Studies On The Mechanism Of Action Of Nerve Growth Factor., D. (Daniel) B. Hier, B. G. Arnason, M. Young

Chemistry Faculty Research & Creative Works

No abstract provided.

Saturated Enthalpies For Mixtures Of Propane And Propene, David B. Manley, George W. Swift

Chemical and Biochemical Engineering Faculty Research & Creative Works

No abstract provided.

The Plasma Polymerization Of Vinyl Monomers. Ii. A Detailed Study Of The Plasma Polymerization Of Styrene, L. F. Thompson, Kenneth G. Mayhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

A study has been made on the plasma polymerization of styrene monomer in a cold, low‐power, inductively coupled RF plasma. Styrene monomer yielded an insoluble, crosslinked film which was slightly colored. A kinetic study is reported for styrene. The effects of power level, bleed rate of monomer, pressure, and reactor geometry on the rate of polymer formation are reported. A mechanism is postulated for plasma polymerization. It was found that the initiation step was the rate controlling step and that the reaction followed a cationic polymerization scheme. Both crosslinking and discoloration of the polymers occur at the time of polymerization …

Assumptions In Forrester's Urban Dynamics Model And Their Implications, Daniel L. Babcock

Engineering Management and Systems Engineering Faculty Research & Creative Works

Forrester's Urban Dynamics model is examined in terms of 1) his assumptions about complex dynamic systems, 2) the a priori bias revealed using a "normalized" model, 3) equilibrium changes when the model is modified to fit urban data, and 4) policy predictions of such a modified model. Copyright © 1972 by The Institute of Electrical and Electronics Engineers, Inc.

The Morphology Of Cellular Precipitation In Aluminum Rich Aluminum-Silver Alloys, Santiago Ibarra Jr.

Doctoral Dissertations

"The morphology of cellular precipitation in Al-29.8wt%Ag alloy has been investigated in bulk specimens by transmission electron microscopy and in solution treated specimens by means of hot stage microscopy. Both cellular and general precipitation were observed to occur simultaneously in quench-aged and isothermally aged alloys. By studying the early stages of precipitation in the hot stage, the mechanism for the growth of cells in Al-Ag alloys was developed. According to this mechanism, the grain boundary allotriomorphs begin to form, the boundary then interacts with the allotriomorphs by bowing, and then either trailing precipitation forms on the allotriomorphs or new lamellae …

Probabilistic Models For Construction Estimating And Bidding, James E. Spooner

Doctoral Dissertations

"Two probabilistic models are offered as a means for quantitatively determining contingency in a lump-sum bid. The first model is based on the isolated project and requires subjective evaluation of probabilities associated with the individual elements of the estimate. Contingency is defined as a function of the standard deviation of project field costs. Procedures are developed to obtain the variance of the total field cost from three-value estimates of the primary quantities. The second model considers the business as a stochastic process with an initial risk reserve and a positive risk loading, and contingency in this model is a function …

Methods And Applications Of Systems Identification, Allen Glenn Behring

Doctoral Dissertations

"A "Schmidt filter" is proposed to compute an optimal orthonormal basis for a set of "noisy" filter input functions. Procedures for determining the transfer function and inverse transfer function of the filter are given. The Schmidt filter is applied to the problem of determining mathematical models of discrete, stationary, linear, dynamic systems for the case where measurements may be corrupted by noise of unknown statistics. The identification problem is reconsidered for the case where noise and signal moments are specified. Procedures are given which insure unbiased, adaptive estimates of system order and parameters for this case. These theoretical propositions are …

Preliminary Studies With A Variable Transfer Composite Polymer Membrane., Samuel Walter Dortch

Masters Theses

"A preliminary study was done to determine the feasibility of using a compressed fibrous teflon (PTFE) silicone polymer membrane in extracorporeal oxygenation devices. A series of composite membranes were fabricated, using different concentrations of a dimethyl silicone polymer dissolved in petroleum ether, to give membranes having variable oxygen transfer properties. A gas-gas system was chosen to obtain the necessary transfer data. Data were obtained by transferring pure oxygen through the membranes into a mixture of 47 mole percent oxygen and 53 mole percent carbon dioxide. All analyses were obtained by chromatographic techniques. The results of these experiments show that membranes …

Analysis And Measurement Of A Zener Diode Voltage-Reference, Armond C. Maxeiner

Masters Theses

"Output voltage sensitivity equations are derived for a zener voltage-reference circuit. The circuit consists of a DC-DC converter, a voltage-resistor current generator, and a zener diode. The performance of the voltage-reference is calculated using the sensitivity equations and compared to measurement data taken from a laboratory model of the circuit. The results are in reasonable agreement.

It was concluded that with careful selection of components, two of three major sources of error can be predicted and controlled; these are changes due to input voltage and changes due to temperature. The third, changes due to time, requires calibration against a voltage …

A Sensitive Temperature Measuring System, Larry Dean Morris

Masters Theses

"A sensitive temperature measuring system, providing an analog output proportional to sensor temperature, has been designed for use in the wall temperature control system of a cloud simulation chamber. A platinum resistance element is the sensor, and a precision wirewound resistor is the reference in a bridge circuit which uses four low cost operational amplifiers arranged to provide two precision 1000 Hz current sources. Problems with an initial bridge amplifier design were corrected in the final design by the use of a low Q bandpass amplifier for the bridge signal followed by a phase detector and an output low pass …

On The Complex Index Of Refraction For Liquids, Juan Guillermo Ochoa Sierra

Masters Theses

"Methods for determining the optical constants, the real and the imaginary part of the complex index of refraction, for weakly and strongly absorbing liquids are reviewed and evaluated. Both reflection and transmission methods were considered and preliminary steps are taken for determining the optical constants for both water and oil in the visible region (0.45 - 0.65 microns) of the spectrum. A low resolution spectrometer was used and the transmission measurements through fuel oil, number 1 through 6, and crude oil were performed. The imaginary part of the complex index of refraction was deduced from the above measurements and appears …

An Investigation Of Stage I Fatigue Crack Growth In Fcc, Bcc, And Hcp Metals, Marion Anthony Russo

Masters Theses

"The objectives of this investigation were to 1) determine if Stage I mode or fatigue crack growth could be extended beyond the 45 degree maximum shear plane in metals having a face-centered, body-centered and hexagonal close pack crystal structure; 2) identify the crystallographic planes or crack propagation in Stage I growth in each crystal structure; 3) characterize the fracture surface topography or Stage I growth in each crystal structure. The test material used for this investigation consisted of alpha brass (70% Cu, 30% Zn), Armco iron and commercially pure titanium which are representative of FCC, BCC, and HCP crystal structures …

Experimental Studies Of Supporting Wire Disturbances In The Near Viscous Wakes Of Slender Supersonic Bodies, Kenneth Anthony Mirly

Masters Theses

"Wires have often been used as a means of mechanically supporting a model so that its wake will be relatively free of support interference. Such support systems have many advantages over stings and are less costly than magnetic suspension systems. Investigations into the disturbances caused by these supporting wires have been carried out with the use of a two-dimensional flat plate and a wire supported slender cone. The tests were conducted in the University of Missouri-Rolla axisymmetric, supersonic wind tunnel at Mach 3.15, and at a Reynolds number of 2.14 X 10⁶ per inch. Schlieren photography, pitot and static pressure …

A Study And Design Of A Cardiac Interbeat Interval Timer System, Richard William Mooney

Masters Theses

"This thesis reports the design of a system which can measure and record the cardiac interbeat times of human subjects in a continuous beat to beat manner, using the bioelectrical signal associated with the heart as an input. The design is in response to the needs of clinical researchers.

The means of obtaining the bioelectrical signal and previous designs of electrocardiographic equipment, especially electrocardiotachometers, are reviewed. A design is proposed which consists of a preamplifier to amplify the bioelectrical signal, a 60 Hz rejection filter, and a beat detector which uses a differentiation technique to obtain a reliable single output …

A Study Of Fmfb Demodulator Operation In The Presence Of Radio Frequency Interference And Gaussian Noise, Terry D. Wormington

Masters Theses

"A digital computer model of an FMFB demodulator has been used to study the effects of radio frequency interference on the detection of a sinusoidally modulated carrier. The effectiveness of selecting the feedback factor to suppress the interference for three values of modulation index is investigated. Also, the required IF bandwidth for the minimization of the mean-square error of the loop output between a signal corrupted by interference and the same signal without interference was investigated. More work is required before the effects of Gaussian noise plus interference on loop operation can be ascertained"--Abstract, page ii.