Engineering Commons^™

Spectroscopic Ellipsometry And Magneto-Optic Kerr Effects In Co/Pt Multilayers, Xiang Gao, Darin W. Glenn, Scott Heckens, Daniel W. Thompson, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

Control of thickness and microstructure is critical in the preparation of ultrathin metallic multilayers for magneto-optic memory, computer read heads, and improved wear surfaces. This paper describes use of in situ spectroscopic ellipsometry to calibrate sputter deposition rates, control layer thicknesses, determine optical constants, and study oxidation rates and processes. In this work, the information gained in situ is used together with ex situ Kerr measurements to determine the complete magneto-optic response including the spectroscopic figure of merit for Co/Pt multilayers.

Sediment Movement Within A Strip Intercropping System, John E. Gilley, L. A. Kramer, R. M. Cruse, A. Hull

Department of Agricultural and Biological Systems Engineering: Faculty Publications

This study was conducted to identify sediment movement within a strip intercropping system in southwestern Iowa during the third year of a three-year crop rotation. Soil loss, resulting from the application of simulated rainfall to a Monona silt loam soil, was measured from individual corn (Zea mays L.), soybean (Glycine max (L.) Merr), and winter wheat (Triticum aestivum L.) strips, and from multiple strips which included all three crops. Because of the crop rotation and residue management procedures, used at the study site, a substantial amount of surface cover and vegetative mass was present on each of …

Process For Producing Biodiesel Fuel With Reduced Viscosity And A Cloud Point Below Thirty-Two (32) Degrees Fahrenheit , Hossein Noureddini

Papers in Biomaterials

Triglycerides are reacted in a liquid phase reaction with methanol and a homogeneous basic catalyst. The reaction yields a spatially separated two phase result with an upper located non-polar phase consisting principally of non-polar methyl esters and a lower located phase consisting principally of glycerol and residual methyl esters. The glycerol phase is passed through a strong cationic ion exchanger to remove anions, resulting in a neutral product which is flashed to remove methanol and which is reacted with isobutylene in the presence of a strong acid catalyst to produce glycerol ethers. The glycerol ethers are then added back to …

Acuta Enews October 1997, Vol. 26, No. 10

ACUTA Newsletters

In This Issue

Marketing Ethernet at Mizzou

Board Report

President's Message

Maximizing Call Center Potential

Welcome New Members

ACUTA Committees at Work

Spotlight

Mizzou

Marketing Committee Needs You!

Lisa Cheshire, CMP

Semer Chairs ASAE Technology Section

DC at a Glance

ACUTA Event Calendar

"Telco Network Whale"

Frequency-Mixing Detection Of Polarization-Modulated Light Using Different Periodic Analyzers, R.M.A. Azzam

Department of Electrical and Computer Engineering: Faculty Publications

We derive the equations that permit the use of six different periodic analyzers for the frequency- mixing detection (FMD) of polarization -modulated light. The six periodic analyzers are (1) the rotating linear analyzer, (2) rotating half -wave plate and fixed linear analyzer, (3) rotating quarter -wave plate and fixed linear analyzer, (4) rotating linear analyzer and fixed linear analyzer, (5) oscillating -phase retarder and fixed linear analyzer, and (6) oscillating optical rotator and fixed linear analyzer. In all cases, the average polarization and the polarization and intensity modulation parameters of the light beam can be determined easily and explicitly from …

Phase And Microstructure Investigations Of Boron Nitride Thin Films By Spectroscopic Ellipsometry In The Visible And Infrared Spectral Range, Eva Franke, Mathias Schubert, Horst Neumann, Thomas E. Tiwald, Daniel W. Thompson, John A. Woollam, Jens Hahn, Frank Richter

Department of Electrical and Computer Engineering: Faculty Publications

Spectroscopic ellipsometry over the spectral range from 700 to 3000 cm^-1 and from 1.5 to 3.5 eV is used to simultaneously determine phase and microstructure of polycrystalline hexagonal and cubic boron nitride thin films deposited by magnetron sputtering on (100) silicon. The results are obtained from a single microstructure-dependent model for both infrared and visible-light thin-film anisotropic dielectric functions. The optical behavior of high c-BN content thin films is described by an effective medium approximation. We obtain the amount of h-BN within high c-BN content thin films. A thin oriented nucleation layer between the silicon substrate …

Multiple Order Dispersive Optics System And Method Of Use, Blaine D. Johs, Ping He, Steven E. Green, Shakil A. Pittal, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

Disclosed is a dispersive optics system, in the context of ellipsometer or polarimeter and the like systems. which, in use. produces a plurality of "Orders" of essentially single wavelength beams of light from a polychromatic beam of light. In use the availability of more than one "Order" of essentially single wavelength beams of light allows simultaneous measurement of more essentially single wavelength beams of light than would be possible were only one "Order" of essentially single wavelength beams of light present. Filters are present to reduce the effects of stray light on detector elements and to allow separating the wavelengths …

Acuta Enews September 1997, Vol. 26, No. 9

ACUTA Newsletters

In This Issue

Telecom Goes Marketing

Board Report

President's Message

Marketing Telecom

Thanks to Sprint for Sponsoring Directory

User Groups Meet in Atlanta and Online

Resource Library Update

Last Call for Directory Updates!

On the Move....

Guide to Distance Learning Available

Internet Call Manager

Spotlight

DC at a Glance

Welcome New Members

ACUTA Event Calendar

Testing Of A Water Loss Distribution Model For Moving Sprinkler Systems, Allen L. Thompson, Derrel L. Martin, John M. Norman, Judy A. Tolk, James R. Gilley, Arlan D. Schneider

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Field water balance measurements using monolithic lysimeters were used in validating the Cupid-DPE model for predicting water loss partitioning during sprinkler irrigation from a moving lateral system fitted with impact sprinklers and spray nozzles. The model combines equations governing water droplet evaporation and droplet ballistics with a comprehensive plant-environment energy balance model. Comparisons indicate good agreement between measured and modeled transpiration, and the measured and modeled soil evaporation during the day of irrigation. Total predicted evapotranspiration during the day of irrigation was greater than measured totals using the monolithic lysimeters. However, part of this difference was because the lysimeters could …

Runoff, Erosion, And Soil Quality Characteristics Of A Former Conservation Reserve Program Site In Southwestern Oklahoma, John E. Gilley, John W. Doran, Thanh H. Dao

Department of Agricultural and Biological Systems Engineering: Faculty Publications

This study was conducted to measure runoff, erosion, and soil quality characteristics of a site in southwestern Oklahoma the first year following conversion from the Conservation Reserve Program (CRP). Treatments included undisturbed CRP, Old World bluestem (Bothriochlora ischaemum L.), no-till wheat (Triticum aestivum L.) and conservation-till wheat. Significant differences in surface cover were found between each of the experimental treatments, with values ranging from 100% on the undisturbed CRP site to 42% for the conservation-till treatment. No significant difference in runoff was found among the various experimental treatments. The Old World bluestem and winter wheat treatments had only …

High-Frequency Response Of Atomic-Force Microscope Cantilevers, Joseph A. Turner, Sigrun Hirsekorn, Ute Rabe, Walter Arnold

Department of Engineering Mechanics: Faculty Publications

Recent advances in atomic-force microscopy have moved beyond the original quasistatic implementation into a fully dynamic regime in which the atomic-force microscope cantilever is in contact with an insonified sample. The resulting dynamical system is complex and highly nonlinear. Simplification of this problem is often realized by modeling the cantilever as a one degree of freedom system. This type of first-mode approximation (FMA), or point-mass model, has been successful in advancing material property measurement techniques. The limits and validity of such an approximation have not, however, been fully addressed. In this article, the complete flexural beam equation is examined and …

Acuta Enews August 1997, Vol. 26, No. 8

ACUTA Newsletters

In This Issue

26th Annual Conference: Highlights from Atlanta

Board Report

President's Message

Rains Came Down, Floods Came Up

Faster Internet Access Over Existing Wiring

Spotlight

Directory Update

Welcome New Members

DC at a Glance

ACUTA Event Calendar

Instant Info

Plasticized, Antiplasticized And Crystalline Conducting Polymers, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Funded Proposals

Materials containing precursors to electrically conductive polymers and electrically conductive polymers are described which have a high degree of crystallinity. The high degree of crystallinity is achieved by preparing the materials under conditions which provide a high degree of mobility to the polymer molecules permitting them to associate with one another to form a crystalline state. High levels of electrical conductivity are achieved in in the electrically conductive materials without stretch orienting the material. The enhanced electrical conductivity is isotropic as compared to a stretch oriented film which has isotropic electrical conductivity.

Acuta Enews July 1997, Vol. 26, No. 7

ACUTA Newsletters

In This Issue

ACUTA Conference Webcast

Board of Directors 1997-98

Board Report

President's Message

Welcome New Members

Music on Hold: Too Soft... Too Loud

Voicemail: Technology We Love to Hate

Spotlight

Anniversaries to Be Recognized

DC at a Glance

Supreme Court Rules Against Communications Decency Act

Determination Of The Interfacial Magneto-Optical Effects In Co/Pt Multilayer Structures, Xiang Gao, Daniel W. Thompson, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

In this letter, we present results of a study of the magneto-optical Kerr response in Co/Pt superlattices by solving for optical constants and Voigt parameters of constituent layers in the structure. The absolute values of the Voigt parameters of Co/Pt interfaces were found to be about twice as large as for the Co layer in the superlattice. Furthermore, using the determined optical constants and Voigt parameters, we can generate the Kerr rotations and ellipticities for Co/Pt superlattices or sandwich structures with continuously changed layer thicknesses and different repeat numbers. Comparison of these theoretical results to the experimental magneto-optical responses for …

Acuta Enews June 1997, Vol. 26, No. 6

ACUTA Newsletters

In This Issue

University of North Dakota Weathers Flood

Board Report

Welcome Donna

Calling All Authors

Internet 2 Goals

Welcome New Members

Spotlight

DC at a Glance

Competition Comes to Canada Telecom

FCC Modifies Caller ID

Laboratory Assessment Of Advanced Oxidation Processes For Treatment Of Explosives And Chlorinated Solvents In Groundwater From The Former Nebraska Ordnance Plant, Elizabeth C. Fleming, Mark E. Zappi, Evelyn Toro, Rafael Hernandez, Karen Myers, Prasad Kodukula, Rosemary Gilbertson

United States Army Corps of Engineers, Omaha District

The study herein was performed through a partnering effort between the U.S. Army Engineer District, Kansas City, Kansas City, MO, and the U.S. Army Engineer Waterways Experiment Station (WES), Vicksburg, MS. The Kansas City District funded portions of this effort as a means of evaluating various treatment options for the contaminated groundwaters at the Nebraska Army Ammunition Plant, Mead, NE.

Some of the WES activities were performed under funding from the U.S. Department of Defense's (DoD) Strategic Environmental Research and Development Program (SERDP). WES has been tasked by SERDP to develop peroxone oxidation as an economical means of decontaminating groundwaters …

Tractor Test Museum Commttee Minutes May 20th, 1997, Tractor Museum

Lester F. Larsen Tractor Museum: Planning and Development Documents

Officer Elections Foundation Funds State Fair Discussions

Acuta Enews May 1997, Vol. 26, No. 5

ACUTA Newsletters

In This Issue

Slate of Nominees Approved

Be a Moderator of Monitor at ACUTA's 26th Annual Conference

Board Report

Univ. of Delaware to Host ACUTA Mid-Atlantic & New England Local Event

Dues Notices Mailed

Welcome Melanie

ACUTA Committees at Work

Spotlight

DC at a Glance

Regulation of BOC Long Distance Services Revised

Welcome New Members

Tillage Effects On Soil Erosion Potential And Soil Quality Of A Former Conservation Reserve Program Site, John E. Gilley, J. W. Doran

Department of Agricultural and Biological Systems Engineering: Faculty Publications

This study was conducted to determine the effects of tillage on soil erosion potential and soil quality characteristics of a former Conservation Research Program (CRP) site. Following tillage, the study area in northern Mississippi was maintained in a fallow condition for nine months. Soil loss from simulated rainfall events was minimal on recently tilled plots and an adjoining, undisturbed CRP area. In contrast, soil loss from the former CRP site which had been tilled nine months previously was similar to values obtained before the CRP program when the area had been cropped for several years. Tillage and over-winter fallowing caused …

In-Situ Ellipsometric Control Of Magnetic Multilayer Deposition (Abstract), Xiang Gao, Scott Heckens, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

Correct determination of layer thicknesses on a subnanometer scale is crucial for studies of giant magnetoresistance, magneto-optical (MO) Kerr rotation, magnetic interlayer coupling, and other magnetic properties of metallic multilayers. Some structures such as [Co/Ni] and [Co/Pt] with fewer than 20 repeats are difficult to be analyzed by x-ray diffraction (XRD) due to too little material. In this work, in-situ spectroscopic ellipsometry (in-situ SE) is used to precisely determine the optical constants undisturbed by oxidation, and the growth rates of different metal films deposited in a sputtering chamber. In-situ SE determines both the constant and continuously changing growth rates …

A Generalized Solidification Model And Microstructural Verification For The Nd–Fe–B–Ti–C System Processed By Rapid Solidification, Matthew J. Kramer, C.P. Li, K.W. Dennis, R.W. Mccallum, C.H. Sellers, D.J. Branagan, Jeffrey E. Shield

Nebraska Center for Materials and Nanoscience: Faculty Publications

For the Nd₂Fe₁₄B (2-14-1) compound, the optimal grain size should be smaller than the size of the single domain size of 150 nm. Transition metal carbides (TMC) also reduce the quench rate necessary to achieve the optimal or overquenched condition. This allows inert gas atomization (IGA) to produce viable magnetic materials. In this article we will demonstrate that optimal microstructure for the 2-14-1 can be produced by IGA with the addition of TiC. Moreover, a solidification model will be presented to show (1) how recalescence is a critical feature to the evolution of the microstructure in …

Monoclonal Antibody Assay And Kit For Detecting Metal Cations In Body Fluids (Continuation), Randall R. Carlson, Jay S. Stout, Dwane E. Wylie, Fred W. Wagner, Malcolm Riddell

Biological Process Development Facility: Staff Publications

The invention provides method and kits for detecting a metallic cation in a sample of a body fluid. The preferred method and kits include the use of at least two different types of antibodies having different specificities. In the preferred method, the sample of body fluid can be contacted with an effective amount of a capture antibody specific for a naturally occurring polypeptide that can bind the metallic cation to form a first antigen-antibody complex. An effective amount of an antibody specific for an epitope on a metallic cation-naturally occurring polypeptide complex or an antibody specific for a metallic cation …

Acuta Enews April 1997, Vol. 26, No. 4

ACUTA Newsletters

In This Issue

Achievement Award Nominations

Listserve Discusses Directory Assistance

Board Report

ATM at UNM

E-mail Etiquette

Spotlight

DC at a Glance

"Internet 2" Links North Carolina

Welcome New Members

Members on the Move

Mlpq: A Linear Constraint Database System With Aggregate Operators, Yiming Li

School of Computing: Dissertations, Theses, and Student Research

In this project report, I will discuss a Multiple Linear Programming Query (MLPQ) system and the theoretical background of this system.The MPLQ system is developed to solve some realistic problems involving both linear programming (UP) techniques and linear constraint databases (LCDBs) theory. The MLPQ system is aimed at providing a mechanism of bridging these two important areas. system basically consists of three parts which are a linear constraint database, an LP solver, and an interface between the LCDB and the LP solver. The LCDB of the MLPQ system contains multiple linear programming problems. The LP solver used in the MPLQ …

Glycerolysis Of Fats And Methyl Esters., Hossein Noureddini, V Medikonduru

Papers in Biomaterials

The glycerolysis of methyl esters and triglycerides with crude glycerol. a coproduct from the transesterification of triglycerides, was studied. Three procedures were followed ior this conversion. The first procedure was a one-step glycerolysis with methyl esters. The second procedure was a two-step process. This proced~~irnev olved an initial partial glycerolysis with methyl esters, followed by fat glycerolysis. The third procedure u,as a simultaneous glycerolysis n,ith methyl esters and triglycerides. In the glycerolysis with methyl esters, the removal of methanol is vital to the production of mono- and diglycerides. Methanol was removed either by drawing vacuum on the reactor or by …

Infrared Ellipsometry On Hexagonal And Cubic Boron Nitride Thin Films, E. Franke, H. Neumann, Mathias Schubert, T. E. Tiwald, John A. Woollam, J. Hahn

Department of Electrical and Computer Engineering: Faculty Publications

Infrared spectroscopic ellipsometry (IRSE) over the wavelength range from 700 to 3000 cm^-1 has been used to study and distinguish the microstructure of polycrystalline hexagonal and cubic boron nitride thin films deposited by magnetron sputtering onto (100) silicon. The IRSE data are sensitive to the thin-film layer structure, phase composition, and average grain c-axes orientations of the hexagonal phase. We determine the amount of cubic material in high cubic boron nitride content thin films from the infrared optical dielectric function using an effective medium approach.

Acuta Enews March 1997, Vol. 26, No. 3

ACUTA Newsletters

In This Issue

Student Paper Competition Nears Deadline

U.S. Court of Appeals stays FCC Detariffing Order

Board Nominations Due April 12

Welcome New Members

Board Report

Same as Sales, But No Commission

Spotlight

DC at a Glance

Publications Committee

ACUTA Membership Renewal

Kinetics Of Transesterification Of Soybean Oil, Hossein Noureddini, D Zhu

Papers in Biomaterials

Transesterification of soybean oil with methanol was investigated. Three stepwise and reversible reacttons are believed to occur. The effect of variations in mixing intensity (Reynolds number = 3,100 to 12,400) and temperature (30 to 70'CJ on the rate oireaction were studied while the molar ratio of alcohol to triglycerol (6:l) and the concentration of catalyst (0.20 wt% based on soybean oil) were held constant. The variations in mixing intensity appear to effect the reaction parallel to the variations in temperature. A reaction mechanism consisting of an initial mass transfer-controlled region followed by a kinetically controlled region is proposed. The experimental …

High-Bandwidth Attitude Jitter Determination For Pointing And Tracking Systems, Marcelo C. Algrain

Department of Electrical and Computer Engineering: Faculty Publications

For many reasons smaller spacecraft are becoming more appealing. Because of their lower inertias, these spacecraft are more sensitive to disturbances and likely to have more attitude jitter than the larger units. These jitter levels are unacceptable for some scientific instruments and need to be compensated. In the case of line-of-sight type instruments, the attitude jitter can be mitigated by incorporating a fast steering mirror into the system. To take full advantage of these devices, the spacecraft attitude must be measured at sufficiently high bandwidth, well beyond what is commonly provided by inertial reference units. Various ways to obtain higher …