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Seasonal Variation In The Stable Isotopic Composition Of Precipitation In The Tropical Montane Forests Of Monteverde, Costa Rica, Amy L. Rhodes, Andrew J. Guswa, Silvia E. Newell

Engineering: Faculty Publications

Climate and land use change may diminish orographic clouds over tropical montane forests, stressing biota and water resources during dry seasons. From 2003 to 2005 we measured the stable isotopic composition of precipitation and throughfall in Monteverde, Costa Rica, to distinguish convective, wet season rainfall associated with the Intertropical Convergence Zone (ITCZ) from dry season, orographic rain produced by northeasterly trade winds. While event-to-event fluctuations of δ18O and δ2H are high, monthly samples reveal a seasonal signal that may be used to trace water through the hydrologic cycle. Deuterium excess indicates that water evaporated from land is an important flux …

Incorporation Of Polyethylene Glycol Into Self-Assembled Monolayers Enhances Substrate-Mediated Gene Delivery By Nonspecifically- Bound Complexes, Angela K. Pannier, Lonnie D Shea

Department of Agricultural and Biological Systems Engineering: Presentations and White Papers

Developing systems capable of controlled and efficient gene transfer is a fundamental goal of biotechnology, with applications including functional genomics, gene therapy, and tissue engineering. Substrate-mediated delivery, also termed solid phase delivery, describes the immobilization of DNA, complexed with nonviral vectors, to a biomaterial or substrate through specific or nonspecific interactions. Cells cultured on the substrate are exposed to elevated DNA concentrations within the local microenvironment, which enhances transfection. We investigated transfection resulting from DNA complexes immobilized to a substrate through specific interactions introduced through complementary functional groups on the vector and surface or through nonspecific interactions. Self-assembled monolayers (SAMs) …

Enzyme–Microbe Synergy During Cellulose Hydrolysis By Clostridium Thermocellum, Yanpin Lu, Yi-Heng P. Zhang, Lee R. Lynd

Dartmouth Scholarship

Specific cellulose hydrolysis rates (g of cellulose/g of cellulase per h) were shown to be substantially higher (2.7- to 4.7-fold) for growing cultures of Clostridium thermocellum as compared with purified cellulase preparations from this organism in controlled experiments involving both batch and continuous cultures. This “enzyme–microbe synergy” requires the presence of metabolically active cellulolytic microbes, is not explained by removal of hydrolysis products from the bulk fermentation broth, and appears due to surface phenomena involving adherent cellulolytic microorganisms. Results support the desirability of biotechnological processes featuring microbial conversion of cellulosic biomass to ethanol (or other products) in the absence of …

Investigation Of Device Parameters For Field-Effect Dna-Sensors By Three-Dimensional Simulation, Eddie Howell, Clemens Heitzinger, Gerhard Klimeck

Other Nanotechnology Publications

The development of a DNA field-effect transistor (DNAFET) simulator is described and implications on device structure and future experiments are discussed. In DNAFETs the gate structure is replaced by a layer of immobilized single-stranded DNA molecules which act as surface probe molecules [1, 2]. When complementary DNA strands bind to the receptors, the charge distribution near the surface of the device changes, modulating current transport through the device and enabling detection (cf. Fig. 1 and 5). Arrays of DNAFETs can be used for detecting singlenucleotide polymorphisms and for DNA sequencing. The advantage of DNAFETs over optical methods of detection is …

Why Don't People Read The Manual?, David G. Novick, Karen Ward

Departmental Papers (CS)

Few users of computer applications seek help from the documentation. This paper reports the results of an empirical study of why this is so and examines how, in real work, users solve their usability problems. Based on in-depth interviews with 25 subjects representing a varied cross-section of users, we find that users do avoid using both paper and online help systems. Few users have paper manuals for the most heavily used applications, but none complained about their lack. Online help is more likely to be consulted than paper manuals, but users are equally likely to report that they solve their …

Fabrication Of Hollow Optical Waveguides On Planar Substrates, John P. Barber

Theses and Dissertations

This dissertation presents the fabrication of hollow optical waveguides integrated on planar substrates. Similar in principle to Bragg waveguides and other photonic crystal waveguides, the antiresonant reflecting optical waveguide (ARROW) is used to guide light in hollow cores filled with liquids or gases. Waveguides with liquid or gas cores are an important new building block for integrated optical sensors. The fabrication method developed for hollow ARROW waveguides makes use of standard microfabrication processes and materials. Dielectric layers are deposited on a silicon wafer using plasma-enhanced chemical vapor deposition (PECVD) to form the bottom layers of the ARROW waveguide. A sacrificial …

Imaging The Mechanical Stiffness Of Skin Lesions By In Vivo Acousto-Optical Elastography, Sean J. Kirkpatrick, Donald D. Duncan, Ruikang K. Wang, Molly Kulesz-Martin, Ken Lee

Electrical and Computer Engineering Faculty Publications and Presentations

Optical elastography is an imaging modality that relies on variations in the local mechanical properties of biological tissues as the contrast mechanism for image formation. Skin lesions, such as melanomas and other invasive conditions, are known to alter the arrangement of collagen fibers in the skin and thus should lead to alterations in local skin mechanical properties. We report on an acousto-optical elastography (AOE) imaging modality for quantifying the mechanical behavior of skin lesions. The method relies upon stimulating the tissue with a low frequency acoustic force and imaging the resulting strains in the tissue by means of quantifying the …

Stanford University’S Small Satellite Program: Amsat Space Symposium, Robert J. Twiggs

Robert "Bob" Twiggs STEM Education Collection

A PowerPoint Presentation created by Professor Bob Twiggs titled "Stanford University’s Small Satellite Program: AMSAT Space Symposium" from October 7, 2006.

Fisheries Research Contract Report No. 14 - Aquatic Animal Health Subprogram: Development Of A National Translocation Policy Using Abalone And Prawns As Templates For Other Aquatic Species (Frdc Project No. 2004/080) Final Report, Brian Jones, Fran Stephens

Fisheries Research Contract Reports

The use of scientifically based hazard identification, risk analysis and risk management is fundamental to managing unwanted effects. Hazards, such as quarantine incursions, will continue to occur despite the use of risk assessment methodologies but the frequency and severity of their occurrence will be reduced.

This was recognised by the Ministerial Council on Forestry, Fisheries and Aquaculture in 1999 when they published the "National policy for the translocation of live aquatic organisms".

This FRDC project provides a simple risk assessment methodology based on the Australian Standard for Risk Management (AS/NZS 4360: 2004) and one that is consistent with the Ministerial …

Investigation Of Ethanol Dehydration In A Microscale Pervaporation Process, Sudhir Ramprasad

Doctoral Dissertations

Challenges due to surface tension effects for vaporization in microchannels have restricted the implementation of conventional separation processes that involve liquid boiling in a micro-chemical system. However, membrane separations offer a feasible alternative for exploring the advantages of liquid phase separation in micro-chemical systems. The main objective of this research was to evaluate the process intensification effects in a microscale pervaporation process with experiments involving the separation of ethanol/water using a commercially available polymer dehydration membrane.

The microchannels in the microseparator were fabricated by the dry etch process at Louisiana Tech University. Microchannel depths of 20 to 120 μm, with …

Engineering@Nebraska - Fall 2006

Engineering@Nebraska (Alumni Magazine)

Table of Contents:

From the Dean
Faculty Profile—It’s Easy Being Green (and Red): Roger Hoy, new director of the Tractor Test Lab, is making sure the 87-year-old operation still meets the needs of today’s industry.
Front and Center
We’ve Got Your Back: Sixty members of the Class of 2010 begin their college careers at a two-day camp just for engineers.
COVER STORY: Where Are The Rest?: Despite increased recruitment efforts, women still comprise only 12 percent of the college’s student body. What has gone wrong, and how can we improve?
Leading By Example: Engineering and architecture students lobby for environmentally …

Optimization Of Active Rendezvous Trajectories By Genetic Algorithms, Marie Emmanuelle Ricour

Master's Theses - Daytona Beach

Trajectory optimization is and will remain a hot topic in the engineering field. Because analytical or exact solutions are often difficult and sometimes impossible to compute, there is a need for alternative and efficient methods. UnderWater Vehicles (UWV) trajectories and rendezvous trajectories of continuous low-thrust spacecraft are examined. One of the methods to solve such problems is the Genetic Algorithm (GA) method. In this work, a GA has been developed using Matlab®. It treats possible solutions to the studied problems as individuals and eventually converges to an optimal or near optimal solution. Genetic Algorithms have been used previously to solve …

Managing Liquid Dairy Manure, José R. Bicudo

Agricultural Engineering Extension Publications

One of the primary issues in the dairy production industry is the storage, management, and land application of manure. Producers should plan how and when to apply manure to agricultural land to minimize the risk of water pollution and odor nuisance and maximize nutrient use.

The Effects Of Tgf-Beta1 And Igf-I On The Biomechanics And Cytoskeleton Of Single Chondrocytes, Nic Leipzig

Chemical, Biomolecular, and Corrosion Engineering Faculty Research

Objective Ascertaining how mechanical forces and growth factors mediate normal and pathologic processes in single chondrocytes can aid in developing strategies for the repair and replacement of articular cartilage destroyed by injury or disease. This study examined effects of transforming growth factor-β1 (TGF-β1) and insulin-like growth factor-I (IGF-I) on the biomechanics and cytoskeleton of single zonal chondrocytes. Method Superficial and middle/deep bovine articular chondrocytes were seeded on tissue culture treated plastic for 3 and 18 h and treated with TGF-β1 (5 ng/mL), IGF-I (100 ng/mL), or a combination of TGF-β1 (5 ng/mL) + IGF-I (100 ng/mL). Single chondrocytes from all …

Designing A Nanotube Using Naturally Occurring Protein Building Blocks, Jie Zheng

Chemical, Biomolecular, and Corrosion Engineering Faculty Research

Here our goal is to carry out nanotube design using naturally occurring protein building blocks. Inspection of the protein structural database reveals the richness of the conformations of proteins, their parts, and their chemistry. Given target functional protein nanotube geometry, our strategy involves scanning a library of candidate building blocks, combinatorially assembling them into the shape and testing its stability. Since self-assembly takes place on time scales not affordable for computations, here we propose a strategy for the very first step in protein nanotube design: we map the candidate building blocks onto a planar sheet and wrap the sheet around …

Nonlinear Modified Pi Control Of Multi-Module Gcscs In A Large Power System, Swakshar Ray, Ganesh K. Venayagamoorthy

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents the design of a new control strategy for gate-controlled series compensators (GCSCs). GCSCs are new FACTS devices which can provide active power flow control on a transmission line. Proper placement of GCSCs in proximity to generators can also provide damping to system oscillations. This paper has investigated the effectiveness of multiple multi-module gate controlled series compensators (MMGCSCs) for large power systems. MMGCSCs can be less expensive devices with wide range of control of capacitive reactance in series with transmission lines. A nonlinear modified PI (NMPI) control is developed to provide power flow control and enhanced transient stability …

Cs 141: Computer Programming I, Michael Ondrasek

Computer Science & Engineering Syllabi

This course provides a general introduction to the fundamentals of computer programming. Examples from and applications to a broad range of problems are given. No prior knowledge of programming is assumed. The concepts covered will be applied to the Java programming language. Students must register for both lecture and one laboratory section.

Cs/Bio 471/671: Algorithms For Bioinformatics, Michael L. Raymer

Computer Science & Engineering Syllabi

Theory-oriented approach to the application of contemporary algorithms to bioinformatics. Graph theory, complexity theory, dynamic programming and optimization techniques are introduced in the context of application toward solving specific computational problems in molecular genetics. 4 credit hours.

Fabrication And Characterization Of Poly(Propylene Fumarate) Scaffolds With Controlled Pore Structures Using 3-Dimensional Printing And Injection Molding, Kee-Won Lee, Shanfeng Wang, Lichun Lu, Esmaiel Jabbari, Bradford L. Currier, Michael J. Yaszemski

Faculty Publications

Poly(propylene fumarate) (PPF) is an injectable, biodegradable polymer that has been used for fabricating preformed scaffolds in tissue engineering applications because of in situ crosslinking characteristics. Aiming for understanding the effects of pore structure parameters on bone tissue ingrowth, 3-dimensional (3D) PPF scaffolds with controlled pore architecture have been produced in this study from computer-aided design (CAD) models. We have created original scaffold models with 3 pore sizes (300, 600, and 900 µm) and randomly closed 0%, 10%, 20%, or 30% of total pores from the original models in 3 planes. PPF scaffolds were fabricated by a series steps involving …

Nutrient Recycling: Rural On-Site Wastewater Disposal And Treatment In Can Tho City, Viet Nam, Micah Johnson

Independent Study Project (ISP) Collection

In order to research a topic a holistic perspective is important. Often experiments are performed absent from the environment that is being observed. It is like thrusting one’s hand into an ocean to grope around for a specimen, extract it, and examine it apart from its native habitat. Although this is possible and often primarily the method, to immerse oneself into where one is studying is to increase one’s ability to obtain a more holistic perspective. I have come to believe that the more practical and accurate scientific experiments are a combination of laboratories and on the field. Not only …

The Effects Of Ultrashort Pulsed Electric Fields On The Fluorescent Molecule Bodipy Fl C5 Ceramide, Rachael Sara Shevin

Electrical & Computer Engineering Theses & Dissertations

Nanosecond pulsed electric fields are able to manipulate internal cell organelles by taking advantage of the small but finite time required for charge to establish across a capacitive barrier. Pulsed electric fields also affect macromolecular structures such as enzymes and proteins. Application of a single nanosecond pulsed electric field decreases the fluorescence of a commercially available biological dye Bodipy FL C₅ Ceramide, used to observe the Golgi apparatus of living cells. The effect is seen when the fluorophore is exposed to an electric field both in vitro and when incorporated into the Golgi of a living Jurkat cell. Observation …

Prediction Of Intrauterine Pressure From Electrohysterography Using Optimal Linear Filtering, Mark D. Skowronski, John G. Harris, Dorothee E. Marossero, Rodney K. Edwards, Tammy Yachabach Euliano

Electrical and Computer Engineering Faculty Research & Creative Works

We propose a method of predicting intrauterine pressure (IUP) from external electrohysterograms (EHG) using a causal FIR Wiener filter. IUP and 8-channel EHG data were collected simultaneously from 14 laboring patients at term, and prediction models were trained and tested using 10-min windows for each patient and channel. RMS prediction error varied between 5-14 mmHg across all patients. We performed a 4-way analysis of variance on the RMS error, which varied across patients, channels, time (test window) and model (train window). The patient-channel interaction was the most significant factor while channel alone was not significant, indicating that different channels produced …

Thermal Analysis Of The Vortex Tube Based Thermocycler For Fast Dna Amplification: Experimental And Two-Dimensional Numerical Results, V. Raghavan, Scott E. Whitney, Ryan J. Ebmeier, Nisha V. Padhye, Michael Nelson, Hendrik J. Viljoen, George Gogos

Hendrik J. Viljoen Publications

In this article, experimental and numerical analyses to investigate the thermal control of an innovative vortex tube based polymerase chain reaction (VT-PCR) thermocycler are described. VT-PCR is capable of rapid DNA amplification and real-time optical detection. The device rapidly cycles six 20 μl 96 bp λ-DNA samples between the PCR stages (denaturation, annealing, and elongation) for 30 cycles in approximately 6 min. Two-dimensional numerical simulations have been carried out using computational fluid dynamics (CFD) software FLUENT v.6.2.16. Experiments and CFD simulations have been carried out to measure/predict the temperature variation between the samples and within each sample. Heat transfer rate …

Low-Frequency Ultrasound Increases Outer Membrane Permeability Of Pseudomonas Aeruginosa, Christopher M. Runyan, John C. Carmen, Benjamin L. Beckstead, Jared L. Nelson, Richard A. Robison, William G. Pitt

Faculty Publications

Low-frequency ultrasound has been investigated as an adjuvant to antimicrobial therapy, targeted at both planktonic and biofilm (sessile) organisms. Our previous work showed that ultrasound (US) effectively enhances the bactericidal activity of certain antibiotics against planktonic cultures (Pitt et al., 1994; Rediske et al., 1999) and in vitro biofilms (Johnson et al., 1998; Qian et al., 1999) and in vivo biofilms (Carmen et al., 2004b, 2005; Rediske et al., 2000) of gram-positive and gram-negative bacteria. Ultrasound was shown to increase the transport of antibiotics through biofilms (Carmen et al., 2004a) which could account for some (or all) of the enhanced …

Magnetic Nanoparticle Supported Catalyst For Atom Transfer Radical Polymerization, Shijie Ding, Yangchuan Xing, Maciej Radosz, Youqing Shen

Chemical and Biochemical Engineering Faculty Research & Creative Works

Magnetic nanoparticles were used to support an ATRP catalyst for the polymerization of methyl methacrylate (MMA) for minimized adverse effect of catalyst support and easy catalyst separation. the nanoparticle-supported catalyst mediated a living/controlled radical polymerization of MMA as effectively as unsupported catalysts. with the addition of 22 mol % of CuBr 2, the polymer molecular weights were well-controlled with an initiator efficiency of 0.85 and polydispersity lower than 1.2. the supported catalysts could be easily separated/isolated using an external magnetic field and reused with slightly decreased activity but further improved control. the activity of the recycled catalyst was regenerated by …

Electrochemical Durability Of Carbon Nanotubes In Noncatalyzed And Catalyzed Oxidations, Liang Li, Yangchuan Xing

Chemical and Biochemical Engineering Faculty Research & Creative Works

Noncatalyzed and catalyzed electrochemical oxidations of multiwalled carbon nanotubes (CNTs) were studied with the aim to understand their durability as catalyst support in polymer electrolyte membrane (PEM) fuel cells. Bare and Pt-deposited CNTs were investigated in 1.0 M sulfuric acid at a constant potential of 1.2 V. Carbon black (CB, Vulcan XC-72R) was also studied under the same experimental conditions. the carbons were oxidized at room temperature in the form of thin-film electrodes with time durations up to 48 h. Cyclic voltammetry was used to monitor the surface oxide redox reactions as a way to quantify the degree of surface …

Biomass Energy Data Book, Volume 1, Lynn Wright, Bob Boundy, Bob Perlack, Stacy Davis, Bo Saulsbury

United States Department of Energy: Publications

The Biomass Energy Data Book is a statistical compendium prepared and published by Oak Ridge National Laboratory (ORNL) under contract with the Office of Planning, Budget, and Analysis in the Energy Efficiency and Renewable Energy (EERE) program of the Department of Energy (DOE). Designed for use as a convenient reference, the book represents an assembly and display of statistics and information that characterize the biomass industry, from the production of biomass feedstocks to their end use.
This is the first edition of the Biomass Energy Data Book and is currently only available online in electronic format. There are five main …

Comppknots: A Framework For Parallel Prediction And Comparison Of Rna Secondary Structures With Pseudoknots, Trilce Estrada, Abel Licon, Michela Taufer

Departmental Technical Reports (CS)

Codes for RNA structure prediction based on energy minimization are usually very time and resource intensive. For this reason several codes have been significantly simplified: in some cases they are unable to predict complex secondary structures such as pseudoknots, while at other times they are able to predict structures with reduced lengths, or they are only able to predict some elementary and simple pseudoknots. Each of the existing codes has its strengths and weaknesses. Providing scientists with tools that are able to combine the strengths of the several codes is a worthwhile objective.

To address this need, we present compPknots, …

Covariance Searches For Ncrna Gene Finding, Jennifer A. Smith

Electrical and Computer Engineering Faculty Publications and Presentations

The use of covariance models for non-coding RNA gene finding is extremely powerful and also extremely computationally demanding. A major reason for the high computational burden of this algorithm is that the search proceeds through every possible start position in the database and every possible sequence length between zero and a user-defined maximum length at every one of these start positions. Furthermore, for every start position and sequence length, all possible combinations of insertions and deletions leading to the given sequence length are searched. It has been previously shown that a large portion of this search space is nowhere near …