Engineering Commons^™

Infrared Switching Electrochromic Devices Based On Tungsten Oxide, E. B. Franke, C. L. Trimble, J. S. Hale, Mathias Schubert, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

Different types of electrochromic devices for thermal emittance modulation were developed in the spectral region from mid- to far-infrared (2–40 μm). In all devices polycrystalline and amorphous tungsten oxide have been used as electrochromic and ion storage layer, respectively. Two types of all-solid-state devices were designed, one with a metal grid for the top and bottom electrode deposited on a highly emissive glass substrate, and another with a top metal grid electrode and a highly reflecting bottom metal electrode layer. Tantalum oxide is used as an ion conductor in both device types. The third device type consists of a polymeric …

Thickness Analysis Of Silicon Membranes For Stencil Masks, E. Sossna, R. Kassing, I. W. Rangelow, C. M. Herzinger, T. E. Tiwald, John A. Woollam, Th. Wagner

Department of Electrical and Computer Engineering: Faculty Publications

Stencil masks are key to charged particle projection lithography, in particular for ion projection lithography. To fulfill pattern printing requirements in the sub-70 nm regime, excellent thickness uniformity and thermal emissivity control are critical parameters for high quality stencil mask fabrication. We propose and demonstrate a technique based on infrared variable angle spectroscopic ellipsometry (IR-VASE) to measure these parameters with adequate accuracy and precision. The refractive index of the Si membrane was evaluated using a Sellmeier dispersion model combined with a Drude model. Because of its spectral range from 2 to 33 μm, the IR-VASE method is sensitive to the …

Dielectric Function Of Amorphous Tantalum Oxide From The Far Infrared To The Deep Ultraviolet Spectral Region Measured By Spectroscopic Ellipsometry, Eva Franke, C. L. Trimble, M. J. Devries, John A. Woollam, Mathias Schubert, F. Frost

Department of Electrical and Computer Engineering: Faculty Publications

Amorphous tantalum oxide thin films were deposited by reactive rf magnetron sputtering onto [001] silicon substrates. Growth temperature, oxygen partial pressure, and total gas pressure have been varied to obtain thin films with different densities. The thin films were analyzed by glancing angle-of-incidence x-ray diffraction, atomic force microscopy, and variable angle-of-incidence spectroscopic ellipsometry in the near infrared to vacuum ultraviolet spectral region for photon energies from E=1 to 8.5 eV, and in the infrared region from E=0.03 to 1 eV. We present the dielectric function of amorphous tantalum oxide obtained by line shape analysis of the experimental ellipsometric …

Acuta Enews November 2000, Vol.29, No. 11

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Runoff And Soil Loss As Affected By The Application Of Manure, John E. Gilley, L. Mark Risse

Biological Systems Engineering: Papers and Publications

Manure has been used effectively to improve crop production and soil properties because it contains nutrients and organic matter. While it is generally accepted that the improved soil properties associated with manure application lead to changes in runoff and soil erosion, few studies have quantified these impacts. Water quality models used to assess watershed management and estimate total maximum daily load must accurately predict loading rates from fields where manure has been applied. This study was conducted to assemble and summarize information quantifying the effects of manure application on runoff and soil loss resulting from natural precipitation events, and to …

Oct 2000, Tractor Museum

Museum Planning and Development Documents

Open House Pedestrian Door Installed Collection of Hand Tools

Lead-Free Interconnection For Electronic Devices, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

An electronic device that is equipped with a plurality of bonding pads positioned on the device for making electrical interconnections and electrically conductive composite bumps adhered to the bonding pads wherein the bumps are formed of a composite material consisting of a thermoplastic polymer and at least about 30 volume percent of conductive metal particles based on the total volume of the metal particles and the thermoplastic polymer. The present invention is also directed to a method of making electrical interconnections to an electronic device by pressing a plurality of composite bumps of a polymeric based material against a substrate …

Modeling Pichia Pastoris Growth On Methanol And Optimizing The Production Of A Recombinant Protein, The Heavy-Chain Fragment C Of Botulinum Neurotoxin, Serotype A, Wenhui Zhang, Mark A. Bevins, Bradley A. Plantz, Leonard A. Smith, Michael M. Meagher

Papers in Biotechnology

An unstructured growth model for the recombinant methylotrophic yeast P. pastoris Mut+ expressing the heavy-chain fragment C of botulinum neurotoxin serotype A [BoNT/A(Hc)], was successfully established in quasi-steady state fed-batch fermentations with varying cell densities. The model describes the relationships between specific growth rate and methanol concentration, and the relationships between specific methanol and ammonium consump-tion rates and specific growth rate under methanol-limited growth conditions. The maximum specific growth rate (μ) determined from the model was 0.08 h−1 at a methanol concentration of 3.65 g/L, while the actual maximum μ was 0.0709 h−1. The maximum specific methanol consumption rate was …

Acuta Enews October 2000, Vol.29, No. 10

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A Statewide Educational Program To Implement Comprehensive Nutrient Management Planning, Richard K. Koelsch, Charles A. Shapiro, R. Wozniak

Department of Biological Systems Engineering: Conference Presentations and White Papers

EPA and USDA NRSC have stated that the most effective way for animal feeding operations (AFO's) to minimize water quality and public health risks is to develop and implement comprehensive nutrient management plans. In response a proposed CNMP workbook has been designed to serve as an animal operation's environmental operating plan. This project will initiate field testing of the proposed Nebraska CNMP with livestock producers and advisors. It will also assist with development of supporting resources and training for educational and technical advisors.

Fuzzy Composite Programming To Combine Remote Sensing And Crop Models For Decision Support In Precision Crop Management, David D. Jones, E. M. Barnes

Biological Systems Engineering: Papers and Publications

Precision crop management is by definition a multi-objective decision-making process that must incorporate a diversity of data, opinion, preference and objective. This paper details an approach to decision making that allows users to express individual or corporate values and preferences; highlights the degree of imprecision associated with each input; highlights the degree of imprecision associated with each alternative; facilitates structuring of the decision process; reduces several levels of complex information into a single chart; allows examination of trade-off between alternatives and interests; and forces examination of inter-relationships between interest. The addition of using remote sensing data provides an efficient method …

Self-Organization In Porous 6h–Sic, S. Zangooie, John A. Woollam, H. Arwin

Department of Electrical and Computer Engineering: Faculty Publications

Pores in porous 6H–SiC were found to propagate first nearly parallel with the basal plane and gradually change direction and align with the c axis. As a consequence, well-defined columnar pores were formed. It was shown that the rate of change of propagation directions was influenced by the etching parameters, such as hydrofluoric acid concentration and current density. Larger currents resulted in formation of larger pores. Pore sizes were found to increase with depth due to a decrease of the acid concentration. In addition, due to chemical etching effects, larger pore sizes were obtained close to the sample surface.

Acuta Enews September 2000, Vol.29, No. 9

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Dielectric Tensor For Interfaces And Individual Layers In Magnetic Multilayer Structures, Xiang Gao, Michael J. Devries, Daniel W. Thompson, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

The magneto-optical Kerr response of metallic magnetic multilayers has been studied by determining the dielectric tensors (dielectric functions) for individual layers, including the magnetic and nonmagnetic interfacial layers. The diagonal components of these tensors were determined using in situ ellipsometric analysis, where the ellipsometric data were taken in real time during multilayer deposition. The off-diagonal components were determined by regression fitting magneto-optic polar Kerr rotation and ellipticity data to models supported by electromagnetic theory. The Voigt parameters (ratio between off-diagonal and diagonal components of dielectric tensors) were determined from these model fits. Higher magnitudes for the Voigt parameters were found …

Phototrophic Anaerobic Lagoons As Affected By Copper And Zinc In Swine Diets, John E. Gilley, Daniel P. Spare, Richard K. Koelsch, Dennis D. Schulte, Phillip S. Miller, Anne M. Parkhurst

Biological Systems Engineering: Papers and Publications

Odor emissions from anaerobic lagoons containing large populations of phototrophic bacteria are usually minimal. This study was conducted to determine whether copper (123 ppm) and zinc (2,310 ppm) in diets fed to weanling pigs for therapeutic purposes affect phototrophic conditions within lagoons. Column reactors containing 47 L of swine lagoon sludge and supernatant were used to represent lagoons. The reactors were placed in an environmental chamber maintained at 24° C. Copper, zinc, and control manure were added to the reactors at a volatile solids loading rate of 128 g_vs m^–3 da^–1 using a hydraulic retention time of …

Fermentation Strategies For Recombinant Protein Expression In The Methylotrophic Yeast Pichia Pastoris, Wenhui Zhang, Mehmet Inan, Michael M. Meagher

Papers in Biochemical Engineering

Fermentation strategies for recombinant protein production in Pichia pastoris have been investigated and are reviewed here. Characteristics of the expression system, such as phenotypes and carbon utilization, are summarized. Recently reported results such as growth model establishment, application of a methanol sensor, optimization of substrate feeding strategy, DOstat controller design, mixed feed technology, and perfusion and continuous culture are discussed in detail.

All-Solid-State Electrochromic Reflectance Device For Emittance Modulation In The Far-Infrared Spectral Region, E. B. Franke, C. L. Trimble, Mathias Schubert, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

All-solid-state electrochromic reflectance devices for thermal emittance modulation were designed for operation in the spectral region from mid- to far-infrared wavelengths (2–40 μm). All device constituent layers were grown by magnetron sputtering. The electrochromic (polycrystalline WO₃), ion conductor (Ta₂O₅), and Li⁺ ion-storage layer (amorphous WO₃), optimized for their infrared (IR) optical thicknesses, are sandwiched between a highly IR reflecting Al mirror, and a 90% IR transmissive Al grid top electrode, thereby meeting the requirements for a reversible Li⁺ ion insertion electrochromic device to operate within the 300 K blackbody emission …

Enhanced Adhesion Between A Vapor Deposited Metal And An Organic Polymer Surface Exhibiting Tailored Morphology, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

Enhanced adhesion between a vapor deposited metal and an organic polymer surface is achieved without utilizing any intermediate surface preparatory steps. The morphology of the polymer surface is tailored to produce mounds and dimples on the surface which leads to a mechanically tougher, interdigitated metal/polymer interface. In the preferred embodiment, a solution of a solvent or solvent system and two or more polymer precursors or polymers or combinations thereof are cast in a film on a substrate and heated to spontaneously form a rough surface due to phase separation. The surface topography of such a film consists of characteristic mounds …

Micro Goniometer For Scanning Microscopy, Ravi F. Saraf

Department of Chemical and Biomolecular Engineering: Patents

A goniometer for performing scanning probe microscopy on a substrate surface is disclosed. The goniometer has a cantilever, having a cantilevered end and a supported end and a tip disposed at the cantilevered end of the cantilever. The goniometer also has a block disposed at the supported end of the cantilever. The block has at least one pair of piezoelectric layers, a pair of electrodes disposed about each individual piezoelectric layer such that varying a potential difference applied between the individual electrodes of a pair of electrodes causes the corresponding piezoelectric layer to deform, and a first insulating material disposed …

Acuta Enews August 2000, Vol.29, No. 8

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Facile Sol-Gel Synthesis Of Porous Silicas Using Poly(Propylene)Imine Dendrimers As Templates, Gustavo F. Larsen, Edgar Lotero, Manuel Marquez

Gustavo Larsen Publications

Commercially available poly(propylene)imine (DAB-Am-32 and DAB-Am-64) dendrimers were used as single-molecule templates to tailor the porosity of silicas via a nonacidic sol-gel method. X-ray diffraction on both the as-prepared (oven-dried at 373 K) and the calcined (833 K) materials revealed that modest contraction took place on template removal and that the cavities created did not achieve three-dimensional ordering under the current synthesis conditions. Transmission electron microscopy of “Pt-stained” samples supported this picture. A modified Horvath–Kawazoe analysis of the argon adsorption isotherms indicated that DAB-Am-64 is a much more effective template than DAB-Am-32. Pyrolysis and oxidation protocols for template removal are …

Jul 2000, Tractor Museum

Museum Planning and Development Documents

Midwest Tool Collectors Annual Meeting Camp Creek Thresher's Event North Door Replaced

Optical Properties Of Bulk And Thin-Film Srtio3 On Si And Pt, Stefan Zollner, A. A. Demkov, R. Liu, P. L. Fejes, R.B. Gregory, Prasad Alluri, J. A. Curless, Z. Yu, J. Ramdani, R. Droopad, T. E. Tiwald, J. N. Hilfiker, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

We have studied the optical properties (complex dielectric function) of bulk SrTiO₃ and thin films on Si and Pt using spectroscopic ellipsometry over a very broad spectral range, starting at 0.03 eV [using Fourier transform infrared (FTIR) ellipsometry] to 8.7 eV. In the bulk crystals, we analyze the interband transitions in the spectra to determine the critical-point parameters. To interpret these transitions, we performed band structure calculations based on ab initio pseudopotentials within the local-density approximation. The dielectric function was also calculated within this framework and compared with our ellipsometry data. In the FTIR ellipsometry data, we notice a …

Acuta Enews July 2000, Vol.29, No. 7

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Acuta Enews June 2000, Vol.29, No. 6

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Piezoelectric Sensors / Actuators For Use In Refractory Environments, Hendrik J. Viljoen, Barend R. Jooste

Papers in Reaction Kinetics

pierozlectric properties over a large temperature range of from room temperature to approximately 1360 degrees centigrade. The piezarlecttic system is sequentially comprised of a first electrically conductive layer, a layer of (Ta,O,) in other than a rnonoclinic phase, ipreferably onhorhombic demonstrating small x-ray crystalopraphic and peaksi. and a second slecttically conductive layer A preferred method of fabrication involves sputter deposition of both said layer of (Ta,O) md said second electrically conductive layer.

Acuta Enews May 2000, Vol.29, No. 5

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Order–Disorder Effects In Nitrided Sm–Fe Permanent Magnets, B.E. Meacham, Jeffrey E. Shield, D.J. Branagan

Nebraska Center for Materials and Nanoscience: Faculty Publications

Rapidly solidified Sm₁₁Fe₈₉ was observed to form partially ordered Sm₂Fe₁₇. The ordering increased systematically with annealing temperature, reaching an order parameter of 0.8 after annealing at 950 °C for 15 min. The coercivity of the corresponding interstitial compound Sm₂Fe₁₇N_x varied with annealing temperature and thus order parameter. The coercivity reached a maximum for an order parameter of 0.45–5, then dramatically decreased as the order increased. This behavior is characteristic of demagnetization controlled by domain wall pinning by antiphase boundaries.

Apr 2000

Museum Planning and Development Documents

State Museum Report Raffle Committee Book Sales Plans

Nanofabrication Using Coulomb Crystals: Giving Shape To The Semiconductor Technology Roadmap, S. Bandyopedhyay, P. F. Williams

P. F. (Paul Frazer) Williams Publications

In 1959, Richard Feynman delivered a lecture with the title, “There is Plenty of Room at the Bottom.” The audience was attendees of the American Physical Society meeting at Caltech. What Feynman, a great seer, talked about was using progressively smaller structures for useful purposes such as storing bits of information.
He even offered a $1,000 (US) prize for anyone who could take the information on the page of a book and put in an area 1/25,000 times smaller in linear scale. In 1986, 26 years after Feynman offered the prize, it was won by a Stanford University graduate student. …