Engineering Commons^™

Energy Absorbing Breakaway Steel Guardrail Post, John R. Rohde, John D. Reid, Dean L. Sicking

Department of Mechanical and Materials Engineering: Faculty Publications

An improved breakaway steel guardrail post for use in dissipation of impact energy upon impact of the post having an upper post member and a lower post member, a connecting joint, and a mechanism connected to the upper and lower post members for controlling the energy dissipation of the guardrail post about the connecting joint at a predetermined rate. A first embodiment utilizes a cable restraint lopped through openings in he guardrail posts. Other embodiments included straps and fasteners disigned to distort or fail at predetermined rates or strengths and combinations thereof.

Acuta Enews July 2001, Vol.30, No. 7

ACUTA Newsletters

In This Issue

Meet the 2001-02 Board

ACUTA Staff Changes

DC Update

Section 508 Sets New Standards

Board Report

FSO and Eye Safety

Welcome New Members

Positions Available

Controlled Buckling Breakaway Cable Terminal, John D. Reid, John R. Rohde, Dean L. Sicking

Department of Mechanical and Materials Engineering: Faculty Publications

A crash attenuation apparatus for use with a guardrail system having rail posts and rail elements. An impact head has a buffer nose section and a rail post breaking beam system. The post breaking beam system has upper and lower breaking beams attached to the head. A guide tube is attached to the side of the head. A strut member extends from a first attachment point on the rail element to a second point downstream. Upon impact by a vehicle, the head breaks the first rail post, before impacting the strut and buckling the rail element downstream.

Acuta Enews June 2001, Vol.30, No. 6

ACUTA Newsletters

In This Issue

History Goes Up in Flames

Web Conference on IP Video

DC Update

Cellular Tower Service Considerations

Disposable Cell Phones

Board Report

Welcome New Members

Positions Available

Superconductivity Of Metallic Boron In Mgb2, J. Kortus, I.I. Mazin, Kirill D. Belashchenko, Vladimir P. Antropov, L.L. Boyer

Nebraska Center for Materials and Nanoscience: Faculty Publications

Boron in MgB₂ forms stacks of honeycomb layers with magnesium as a space filler. Band structure calculations indicate that Mg is substantially ionized, and the bands at the Fermi level derive mainly from B orbitals. Strong bonding with an ionic component and considerable metallic density of states yield a sizable electron-phonon coupling. Together with high phonon frequencies, which we estimate via zone-center frozen phonon calculations to be between 300 and 700 cm^-1, this produces a high critical temperature, consistent with recent experiments. Thus MgB₂ can be viewed as an analog of the long sought, but still …

Inverse Synthetic Aperture Radar Imaging Using A Coherent Ultrawideband Random Noise Radar System, Daryl C. Bell, Ram M. Narayanan

Department of Electrical and Computer Engineering: Faculty Publications

The University of Nebraska-Lincoln has developed an ultrawideband random noise radar operating over the 1- to 2-GHz frequency range. The system uses the technique of heterodyne correlation, and is thus phase coherent. It has therefore been used in applications such as interferometry, polarimetry, and Doppler estimation. This assesses the performance of this radar as a range-Doppler imaging system, in particular, inverse synthetic aperture radar (ISAR). By performing turntable experiments, we examine a number of issues that arise both from the wideband nature of the radar system and from the randomness of the transmit signal. Although the ultrawideband nature of the …

Production Of Microcrystalline Cellulose By Reactive Extrusion, Milford Hanna, Gerald Biby, Vesselin Miladinov

Industrial Agricultural Products Center: Publications and Information

This process involves feeding cellulose into an extruder with an acid solution. The extruder is comprised of a screw and a barrel. The screw is rotated so as to pressurize the cellulose, and the cellulose undergoes acid hydrolysis and forms microcrystalline cellulose. The invented process can be accomplished by using pure cellulose or a lignocellulosic material as the starting material. If a lignocellulosic material is used, then a basic solution is added to it and the lignocellulosic material is fed through an extruder so as to obtain a mixture comprising lignin, hemicellulose and cellulose. The lignin and hemicellulose are extracted …

Acuta Enews May 2001, Vol.30, No. 5

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ACUTA Leadership Awards

Assigned to EDUCASUE

DC Update

Overheard on the Listserve: LECs, CLECs, and Resale

Board Report

Welcome New Members

Positions Available

Infrared Optical Properties Of Aged Porous Gaas, S. Zangooie, Mathias Schubert, T. E. Tiwald, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

Aging properties of porous GaAs were investigated nondestructively using variable angle of incidence infrared spectroscopic ellipsometry. In addition to the thickness and volume porosity, properties of the solid part of the porous material are investigated in terms of the long-wavelength dielectric function and chemical composition. The high sensitivity is employed to detect and identify infrared resonant absorptions related to different vibration modes of cubic and amorphous As₂O₃. Resonances centered at 333.3, 480, 785.8, 838, and 1045.5 cm^-1 are from cubic As₂O₃, whereas resonances centered at 350, 490, and 808.5 cm^{-1 …}

Scattering Of Elastic Waves In Heterogeneous Media With Local Isotropy, Joseph A. Turner, Phanidhar Anugonda

Nebraska Center for Materials and Nanoscience: Faculty Publications

The scattering of elastic waves in heterogeneous media is discussed. Explicit expressions are derived for the attenuation of longitudinal and transverse elastic waves in terms of the statistics of the density and Lame´ parameter fluctuations. The derivation is based upon diagrammatic methods with the problem posed in terms of the Dyson equation. The Dyson equation is solved for the mean field response. The results are given here in a straightforward manner, in which the attenuations reduce to simple integrals on the unit circle. The medium is assumed statistically homogeneous and statistically isotropic. This model, with assumed local isotropic properties, is …

Aspect Sensitivity Measurements Of Polar Mesosphere Summer Echoes Using Coherent Radar Imaging, P. B. Chilson, T.-Y. Yu, R. D. Palmer, S. Kirkwood

Department of Electrical and Computer Engineering: Faculty Publications

The Esrange VHF radar (ESRAD), located in northern Sweden (67.88) N, 21.10- E), has been used to investigate polar mesosphere summer echoes (PMSE). During July and August of 1998, coherent radar imaging (CRI) was used to study the dynamic evolution of PMSE with high temporal and spatial resolution. A CRI analysis provides an estimate of the angular brightness distribution within the radar’s probing volume. The brightness distribution is directly related to the radar reflectivity. Consequently, these data are used to investigate the aspect sensitivity of PMSE. In addition to the CRI analysis, the full correlation analysis (FCA) is used to …

Electrode Modification Using An Unzippable Polymer Paste, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

A paste is described for capping electrodes with an oxide free metal layer incorporating a solvent, an unzippable polymer and particles. The electrode could be an interconnect such as a C4 bump. A method for forming a coating and for testing integrated circuit chips is also described. The invention overcomes the problem of interconnecting Pb containing electrodes that are covered with an insulating oxide on integrated circuit chips by coating the Pb containing electrode with Au to provide an oxide free surface for testing and interconnection.

Ultra High Density Storage Media And Method Thereof, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

A storage media for storing information having a substrate. The substrate has an upper surface and a molecular weight greater than 5,000. Preferably the material is a polymer. The material has a plurality of piles of molecular chains in selected areas formed by pushing the molecular chains of the material on its upper surface to the selected area mechanically with a mechanical tool. The piles represent written information. The mechanical tool is preferably an atomic force microscope. Another aspect of the present invention is a method for storing information having the steps of selecting a material substrate having an upper …

Apr 2001, Tractor Museum

Lester F. Larsen Tractor Museum: Planning and Development Documents

Camp Creek Swap Meet Public Relations Get Fordson Running

Motorized Insulated Damper Assembly For Furnace Systems, William Max Kirk, Timothy Wentz

Durham School of Architectural Engineering and Construction: Faculty Publications

A damper unit is provided that is adapted to be positioned in a furnace duct line. The damper unit has a housing which is in communication with a fresh air source and a furnace system. The housing has a damper blade which is moveable between an open position which allows air flow through the housing and a closed position which prevents air flow through the housing. The blade is coupled with a Solenoid so that when the Solenoid is activated the blade is moved to an open position allowing air flow through the housing. Further, a fan is located in …

Polycrystalline Conducting Polymers And Precursors Thereof Having Adjustable Morphology And Properties, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

Polycrystalline materials containing crystallites of precursors to electrically conductive polymers and electrically conductive polymers are described which have an adjustable high degree of crystallinity. The intersticial regions between the crystallites contains amorphous material containing precursors to electrically conductive polymers and /or electrically conductive polymers. The 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. This is preferable achieved by including additives, such as plasticizers and diluents, to the solution from which the polycrystalline material is …

Nebraska Blueprint - Spring 2001

Nebraska Blueprint (Student Publication)

Table of Contents:

From the Editor
Students uncover the secrets of the Magic Kingdom
Student Life on the Sixth Floor
Celebrating National Engineers Week at PKI
NSBE lights its torch at UNL
Undergraduates benefit from conducting research
Postcard from Paris
Out of the starting blocks

Acuta Enews April 2001, Vol.30, No. 4

ACUTA Newsletters

International Rates Increasing

Guide to Developing Online Students Services

DC Update

Detariffing International Service

VIPs Visit Carnegie-Mellon

Board Report

Welcome New Members

Positions Available

Lead Free Conductive Composites For Electrical Interconnections, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

An electrically conductive paste which includes a thermoplastic polymer, a conductive metal powder and an organic solvent system is disclosed. The invention further encompasses an electrically conductive composite which includes the aforementioned thermoplastic and metal, wherein the metal represents at least about 30% by volume, based on the total volume of the composite. The composite is formed from the paste under elevated temperature. The paste is employed in processes which involve electrically connecting electrical and electronic components under process conditions which convert the paste to the composite.

Study Of Surface Chemical Changes And Erosion Rates For Cv-1144-O Silicone Under Electron Cyclotron Resonance Oxygen Plasma Exposure, Li Yan, Xiang Gao, Corey Bungay, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

CV-1144-O silicone thin films were irradiated in an electron cyclotron resonance oxygen plasma, which is a simulation of the low earth orbital environment. A crude equivalence between this plasma system and the low earth orbital environment was determined by measuring Kapton weight loss in the plasma and comparing to Kapton weight loss in space experiments. Changes in optical properties and erosion rates under ultraviolet light and atomic oxygen radiation were studied using in situ spectroscopic ellipsometry (SE). The erosion rate at the beginning of the plasma exposure was significantly faster than that at later stages. Approximately one third of the …

Acuta Enews March 2001, Vol.30, No. 3

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ACUTA Resource Library Is Growing

Spotlight on Volunteers

DC Update

Kent State Wins Network World Award

Overheard on the Listserve: Who Owns the Cable?

High Tech Short Takes

Welcome New Members

Positions Available

Analysis Of Microdamage Evolution Histories In Composites, Yuris A. Dzenis, Jie Qian

Department of Engineering Mechanics: Faculty Publications

Evolution of microdamage in advanced composites was experimentally studied in this paper. A new method of acoustic emission (AE) analysis of histories of different damage mechanisms was formulated based on a combination of transient AE classification and multiparameter filtering. The capabilities of the method were illustrated on examples of damage evolution in several graphite/epoxy composites. Three characteristic AE waveforms with different frequency spectra were identified based on the transient analysis. Regions occupied by these waveforms in the amplitude–rise time parametric space were identified for the [0]₈ and [90]₁₆ unidirectional composites. Multiparameter filtering was applied to extract evolution histories …

Effects Of Concentration And Temperature On The Coupled Heat And Mass Transport In Liquid Mixtures, Yaşar Demirel, Stanley I. Sandler

Papers in Thermal Mechanics

Using published experimental data on the thermal conductivity, mutual diffusivity, and heats of transport, the degree of coupling between heat and mass flows has been calculated for binary and ternary nonideal liquid mixtures. The binary mixtures consist of two types: the first is six systems of six-to-eight-carbon straight and branched chain alkanes in chloroform and in carbon tetrachloride; and the second is mixtures of carbon tetrachloride with benzene, toluene, 2-propanone, n-hexane, and 11-octane. The ternary mixture considered is toluene-chlorobenzene-bromobenzene. The published data are available at 35°C, 30°C, and 35°C and ambient pressure. Using the linear nonequilibi-ium thermodynainics (LNET) and the …

Immunosorbents With Developed Binding Efficiency And Method Of Manufacture , William H. Velander

Department of Chemical and Biomolecular Engineering: Patents

The antitope of an antibody is masked with a masking agent, followed by immobilization on a support. The masking agent is then eluted to produce an improved immunosorbent, which is capable of binding more than double the amount of an antigen than existing immunosorbents having the same antibody bound at the same density. Preferably, the masking agent is an antigen or other compound having an epitope for which the antitope of the bound antibody has an avidity. In a preferred embodiment, greater than 30% of the bound antibodies maintain the same vicinity as when unbound for specific antigen or hapten …

Enhanced Transition Temperature In A Quantum Confined High-TC Superconductor, L. Menon, D. Yu, Yi Liu, B. Jayaram

P. F. (Paul Frazer) Williams Publications

A slight enhancement of the onset transition temperature T_c has been observed in quantum dots of the high-T_c superconductor yttrium–barium–copper oxide (Y₁Ba₂Cu₃O_7-δ). The dots were formed when YBCO particles (diameter ≤600 nm) were exposed to an RF plasma to produce a Coulomb crystal. The plasma damages the particles and causes 20–25 nm sized isolated islands of the correct 1-2-3 stoichiometry to segregate within each particle. We believe that quantum confinement of carriers within these islands leads to discretization of the quasi-particle density-of-states which can account for the slight increase …

Michaelis–Menten Kinetics For Enzymatic Depolymerization Of A Linear Polyester Synthesized From Z-Protected Glutamic Acid, R. M. Tadros, Hossein Noureddini, Delmar C. Timm

Papers in Biomaterials

A biodegradable polyester resin was polymerized from N-benzyloxycarbonyl-L-glutamic acid and ethylene glycol. Rhizopus delemar lipase was used as a biocatalyst for the rupture of ester bonds during the hydrolysis studies. Depoly-merization was observed to followa Michaelis–Menten mechanism, with the maximumrate of monomer formation dP/dt_max = 1.12 x 10^-8 mol/s and the rate constant K_m x 2.03 x 10^-4 mol. Subject to initial conditions described by the most probable distribution and Michaelis–Menten–type depolymerization rate expressions, population density distribution dynamics of the polymeric molecules that formed the resin were explicitly described using a deterministic approach.

Infrared Response Of Multiple-Component Free-Carrier Plasma In Heavily Doped P-Type Gaas, S. Zangooie, Mathias Schubert, Daniel W. Thompson, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

Spectroscopic ellipsometry is used to measure the dielectric function of heavily doped p-type GaAs for wave numbers from 100 to 2000 cm^-1. Due to partial filling of the heavy- and light-hole valence bands, heavy holes as well as light holes form a multiple-component plasma coupled with longitudinal optical phonons. Line-shape analysis of the infrared response allows differentiating between light- and heavy-hole contributions to the carrier plasma, and the results observed suggest nonparabolicity effects of the heavy- and light-hole valence bands in GaAs.

Rate Effects On Mode-I Delamination Toughness Of A Graphite/Epoxy Laminated Composite, Xiangfa Wu, Yuris A. Dzenis

Department of Engineering Mechanics: Faculty Publications

Mechanical properties of composite materials made of high modulus fibers and relatively low modulus polymeric matrix, such as graphite/epoxy laminated composites, are sensitive to loading rate and temperature. Generally, at fixed loading rate, when temperature increases, the fracture toughness of polymers also increases; however, it will decrease with the increase of loading rate at constant testing temperature. Rate effects on fracture toughness are of critical to understand the fracture transition from ductile to brittle of some polymers. However, there have been fewer studies of rate effects on delamination toughness of laminates compared to that of pure polymers. In the present …

Acuta Enews February 2001, Vol.30, No. 2

ACUTA Newsletters

In This Issue

Nominations Sought for Board of Directors

Spotlight on Volunteers

DC Update

A Portal Primer

Cellular Phones for Residence Halls?

Board Report

Welcome New Members

Positions Available

Effects Of External Electric Field On The Interfacial Properties Of Weakly Dipolar Fluid, V. B. Warshavsky, T. V. Bykov, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

In the framework of modified mean-field density-functional theory, effects of a uniform electric field on the interfacial properties of a model dipolar fluid are studied. Both density and orientational order-parameter profiles of the planar vapor-liquid interface are obtained as a function of the field strength. For the dipolar fluids with reduced dipole moment μ₀^*0^*E*/T*!1) can shift the surface tension by few percent. We also find that the electric field actually reduces the thermodynamical surface tension but enhances the mechanical surface tension at the equimolar dividing surface. To detect these field effects on …