Engineering Commons^™

Macromolecules In The 21st Century: An International Symposium On Polymer Science And Technology On The Occasion Otto Vogl's 75th Birthday, Gerald S. Kirshenbaum, Helga Roder

Otto Vogl

No abstract provided.

Tethered Nano Building Blocks: Toward A Conceptual Framework For Nanoparticle Self-Assembly, Zhenli Zhang, Mark A. Horsch, Monica H. Lamm, Sharon C. Glotzer

Monica H. Lamm

We perform molecular simulations to study the self-assembly of nanoparticles functionalized with oligomeric tethers attached to specific locations on the nanoparticle surface. We demonstrate that for certain categories of tethered nano building blocks the obtained morphologies may be predicted using concepts from block copolymer microphase separation and liquid-crystal phase ordering, whereas for other categories the unique packing constraints introduced by nanoparticle geometry and by nanoparticle-tether topology lead to structures far richer than those found in conventional block copolymer, surfactant, and liquid-crystal systems. Our results suggest the potential usefulness of considering tethered nano building blocks as a new class of "macromolecule" …

2dsim: A Prototype Of Nanoscopic Traffic Simulation, Daiheng Ni

Daiheng Ni

This paper reviews and compares car-following and lane- changing logics embedded in some microscopic traffic simulation models, and comments are made on the existing techniques of traffic simulation. Future directions of traffic simulation are identified in three aspects: vehicle modeling, driver modeling, and vehicle movement modeling. To illustrate these ideas, a conceptual model, 2DSIM, is proposed, which consists of a dynamic vehicle sub-model and an intelligent driver sub-model. They are further integrated into a driver-vehicle-environment closed-loop system which constitutes the basic building block of road traffic.

Simulation Of Freeway Merging And Diverging Behavior, Daiheng Ni, John D. Leonard

Daiheng Ni

Simplified theory of kinematic waves was proposed by Newell and uses cumulative arrival and departure counts to describe kinematic waves of freeway traffic. The original paper deals only with traffic on freeway mainline. It is of great interest, at least practically, to investigate whether the simplified theory can be used to simulate freeway traffic merging and diverging behavior. In his paper, Newell as- sumed that on-ramp traffic always has the priority and can bypass queues, if any. This assumption will be released so that traffic from the mainline and the on-ramp will have to compete for downstream supply. For off-ramps, …

Characterizing Volatile Fatty Acids And Other Gases In A Rumen Closed In Vitro Fermentation System Using Solid Phase Microextraction, Jarett P. Spinhirne, Jacek A. Koziel, Norbert K. Chirase

Jacek A. Koziel

A new method for rapid sampling and qualitative characterization of the headspace gases of closed in vitro cultures using solid phase microextraction (SPME) was evaluated for ruminal fluid and ruminal fluid with feed containing a feed additive. Gas sample collection was achieved by exposing a DVB/Carboxen/PDMS 50/30 .m SPME fiber to the headspace of cultures for 1 min every hour. This was followed by immediate analysis on a GC–MS and then reuse of the SPME fiber. Acetic, propionic, isobutyric, butyric, isovaleric, valeric, and hexanoic acids and toluene, dimethyl disulfide, and pentadecane were identified in the headspace. SPME technology facilitated rapid …

Generation And Calibration Of Standard Gas Mixtures For Volatile Fatty Acids Using Permeation Tubes And Solid-Phase Microextraction, Jacek A. Koziel, Jarett P. Spinhirne

Jacek A. Koziel

Volatile fatty acids (VFAs) are major components of odors associated with agricultural operations and livestock housing, solid waste processing and disposal, industrial and municipal wastewater collection, and treatment systems. Emission estimation and assessment of odor control methods depend on reliable air sampling and analysis methods for VFAs. The objective of this research was to develop and test a method for continuous and reliable generation of standard gas mixtures for VFAs based on permeation tubes. Standard gas mixtures for acetic, propionic, isobutyric, butyric, isovaleric, valeric, and hexanoic acids were generated with permeation tubes and monitored for a 100-day period. The gravimetric …

Beta Zeolite Supported On Silicon Carbide For Friedel–Crafts Fixed-Bed Reactions, Gauthier Wine, Joseph Matta, Jean-Philippe Tessonnier, Cuong Pham-Huu, Marc-Jacques Ledoux

Jean-Philippe Tessonnier

Beta zeolite supported on silicon carbide, with high thermal conductivity and high mechanical strength, was successfully used as an active and stable catalyst for Friedel-Crafts reactions in a fixed bed configuration.

Design Of Abc Triblock Copolymers Near The Odt With The Random Phase Approximation, Eric W. Cochran, David C. Morse, Frank S. Bates

Eric W. Cochran

Leibler’s random phase approximation for block copolymers, modified so as to be applicable to linear multiblock copolymers, has been quantitatively compared to data from three linear ABC/ACB triblock copolymer melts: poly(cyclohexylethylene-b-ethylene-b-ethylethylene) (CEEE)/CEEE, poly(styreneb- isoprene-b-ethylene oxide) (SIO)/ISO (Macromolecules 2001, 34, 6994-7008;Macromolecules 2002, 35, 7007-7017), and poly(styrene-b-isoprene-b-dimethylsiloxane) (SID)/ISD (Macromolecules 2002, 35, 3189- 3197). The RPA calculation provides the mean-field static structure factor for a disordered block copolymer melt, which can be used to anticipate the scattering behavior and spinodal stability limit temperature (Ts); in the context of mean-field theory, the spinodal should lie near the order-disorder-transition temperature (TODT). We find that the …

Periodic Broadcast And Patching Services - Implementation, Measurement And Analysis In An Internet Streaming Video Testbed, Mk Bradshaw, B Wang, S Sen, Lx Gao, J Kurose, P Shenoy, D Towsley

Lixin Gao

No abstract provided.

Impedance Probe To Measure Local Gas Volume Fraction And Bubble Velocity In A Bubbly Liquid, Ashok S. Sangani, R. Zenit, D. L. Koch

Ashok S. Sangani

We have developed a dual impedance-based probe that can simultaneously measure the bubble velocity and the gas volume fraction in length scales comparable to the bubble diameter. The accurate determination of the profiles is very important for comparisons with existing theories that describe the rheological behavior of bubbly liquids. The gas volume fraction is determined by the residence time of bubble within the measuring volume of the probe. We have found that the details of the bubble-probe interactions must be taken into account to obtain an accurate measure of the gas volume fraction at a point. We are able to …

Mass Transfer Coefficients For Laminar Longitudinal Flow In Hollow-Fibre Contactors, Ashok S. Sangani, Sangkyun Koo

Ashok S. Sangani

We consider the problem of predicting the rate of mass transfer to a fluid flowing parallel to the axes of randomly placed aligned tubes, a model of hollow-fibre contactors. The analysis is carried out for the limiting cases of short contactors, for which the concentration boundary layers remain thin compared with the radius of the tubes, and for the fully developed case corresponding to very long tubes. Numerical simulations for random arrays are carried out for N randomly placed tubes within a unit cell of a periodic array. It is shown that the mass transfer coefficient for the fully developed …

From Learning To Talk To Learning Engineering; Drawing Connections Across The Disciplines, Nikos J. Mourtos

Nikos J. Mourtos

No abstract provided.

Cell And Organ Printing 2: Fusion Of Cell Aggregates In Three-Dimensional Gels, Thomas Boland, Vladimir Mironov, Anna Gutowska, Elisabeth Roth, Roger Markwald

Thomas Boland

We recently developed a cell printer (Wilson and Boland, 2003) that enables us to place cells in positions that mimic their respective positions in organs. However, this technology was limited to the printing of two-dimensional (2D) tissue constructs. Here we describe the use of thermosensitive gels to generate sequential layers for cell printing. The ability to drop cells on previously printed successive layers provides a real opportunity for the realization of three-dimensional (3D) organ printing. Organ printing will allow us to print complex 3D organs with computer-controlled, exact placing of different cell types, by a process that can be completed …

Manufacturing Interoperability, Steven Ray, Al Jones

Steven R Ray

As manufacturing and commerce become ever more global in nature, companies are increasingly dependent upon the efficient and effective exchange of information with their partners, wherever they may be. Leading manufacturers rely upon computers to perform this information exchange, which must therefore be encoded for electronic transmission. Because no single company can dictate that all its partners use the same software, standards for how the information is represented become critical for cost-effective, errorfree transmission of data. This paper discusses some interoperability issues related to current standards, and describes two projects underway at the National Institute of Standards and Technology in …

Cell And Organ Printing 1: Protein And Cell Printers, Cris Wilson, Thomas Boland

Thomas Boland

We have developed several devices for positioning organic molecules, molecular aggregates, cells, and single-cell organisms onto solid supports. These printers can create stable, functional protein arrays using an inexpensive technology. The cell printer allows us to create cell libraries as well as cellular assemblies that mimic their respective position in organs. The printers are derived from commercially available ink-jet printers that are modified to dispense protein or cell solutions instead of ink. We describe here the modifications to the print heads, and the printer hardware and software that enabled us to adapt the ink-jet printers for the manufacture of cell …

Autonomous Vehicles Research Laboratory – Phase Ii: Mobile Robots And A Walking Internet, Raúl Ordóñez

Raúl Ordóñez

PI, Funded by the University of Dayton Research Council, $8,000.

Bayesian Modelling And Forecasting Of Intra-Day Electricity Load, Remy Cottet, Michael Smith

Michael Stanley Smith

With the advent of wholesale electricity markets there has been renewed focus on intra-day electricity load forecasting. This paper employs a multi-equation regression model with a diagonal first order stationary vector autoregresson (VAR) for modeling and forecasting intra-day electricity load. The correlation structure of the disturbances to the VAR and the appropriate subset of regressors are explored using Bayesian model selection methodology. The full spectrum of finite sample inference is obtained using a Bayesian Markov chain Monte Carlo sampling scheme. This includes the predictive distribution of load and the distribution of the time and level of daily peak load, something …

Working Across Cultures, John Hooker

John Hooker

No abstract provided.

Characterization Of Patterned Self-Assembled Monolayers And Protein Arrays Generated By The Ink-Jet Method, Laura Pardo, Thomas Boland

Thomas Boland

Commercial ink-jet printers were used with little modification to deposit alkanethiols onto gold substrata and several proteins onto silica supports. The resulting patterns of alkanethiols form self-assembled layers comparable to those obtained by microcontact printing or solution adsorption. The method has been used successfully to create binary chemical gradients and patterns of tertiary functionality. The proteins form dense patterns on the substrates and seem to maintain their configuration as measured by their ability to bind their specific ligands. Four different proteins were printed simultaneously, allowing for positive and negative controls. This "drop-on-demand" printing method is an inexpensive, flexible alternative to …

Organ Printing: Computer Aided Jet Based 3d Tissue Engineering, Vladimir Mironov, Thomas Boland, Thomas Trusk, Gabor Forgacs, Roger Markwald

Thomas Boland

Tissue engineering technology promises to solve the organ transplantation crisis. However, assembly of vascularized 3D soft organs remains a big challenge. Organ printing, which we define as computer-aided, jet-based 3D tissue-engineering of living human organs, offers a possible solution. Organ printing involves three sequential steps: pre-processing or development of "blueprints" for organs; processing or actual organ printing; and postprocessing or organ conditioning and accelerated organ maturation. A cell printer that can print gels, single cells and cell aggregates has been developed. Layer-by-layer sequentially placed and solidified thin layers of a thermo-reversible gel could serve as "printing paper". Combination of an …

A Quantitative Approach To Studying Structures And Orientation At Self- Assembled Monolayer/Fluid Interfaces", Laura Pardo, Thomas Boland

Thomas Boland

Self-assembled monolayers (SAMs) have become a standard tool for exploring surface interactions. Although well characterized, SAMs are known to undergo structural and conformational changes in the presence of solution, yet the ability to quantify these changes remains an obstacle due to limited analytical techniques. In this study, we determine changes in structure and conformation of CH3, OH, and COOH terminated hexadecanethiols on gold in water by means of a new technique known as evanescence reflection spectroscopy. This FTIR application, in conjunction with a semiempirical formalism, is capable of providing both qualitative and quantitative understanding of the molecular structure and orientation …

Apparatus For Illuminating The Tip-Sample Interface Of An Atomic Force Microscope, Nancy Burnham, E Thoreson

Nancy A. Burnham

An apparatus for the delivery of radiation to the tip-sample interface of an atomic force microscope(AFM) is demonstrated. The pulsed light delivery system (PLDS) was fabricated to probe photoinduced conformational changes of molecules using an AFM. The system is 67 mm long, 59 mm wide, and 21 mm high, leaving clearance to mount the PLDS and a microscope slide coated with a thin film of photoactive molecules beneath the cantilever tip of a stand-alone AFM. The PLDS is coupled into a fiber pigtailed Nd:yttrium–aluminum–garnetfrequency doubled laser, operating at a wavelength of 532 nm. The radiation delivered to a sample through …

Application Of Fuzzy Logic To Systems Engineering, Caroline Lubert

Caroline P Lubert

No abstract provided.

Measuring Electrocatalytic Activity On A Local Scale With Scanning Differential Electrochemical Mass Spectrometry, K. Jambunathan, Andrew C. Hillier

Andrew C. Hillier

This paper describes a new technique entitled scanning differential electrochemical mass spectrometry ~SDEMS! that combines a quadrupole mass spectrometer with a membrane-covered capillary inlet and a high resolution positioning system that is designed to perform spatial mapping in solution near an electrode interface. Potential applications of this technique include the local characterization of anode catalysts for fuel cells as well as a range of analytical measurements and combinatorial screening studies. The capabilities of this technique are demonstrated by monitoring product evolution in several model electrocatalytic reactions, including the hydrogen evolution reaction, carbon monoxide oxidation, and the direct oxidation of methanol …

Screening The Reactivity Of Ptxruy And Ptxruymoz Catalysts Toward The Hydrogen Oxidation Reaction With The Scanning Electrochemical Microscope, S. Jayaraman, Andrew C. Hillier

Andrew C. Hillier

We report an application of the scanning electrochemical microscope that exploits its ability to spatially map the kinetics of heterogeneous electron-transfer reactions in order to perform screening measurements for combinatorial studies of electrooxidation catalysts. The ability to measure the activity of catalyst surfaces toward the hydrogen oxidation reaction via tip−sample feedback is used to characterize the activity of PtxRuy and PtxRuyMoz catalysts as a function of composition and electrode potential. Multielement band electrodes containing various compositions of PtxRuy and PtxRuyMoz deposits are created via pulsed electrochemical deposition onto patterned substrates. Catalyst compositions are verified through a combination of Auger electron …

Spherulite Formation From Microphase-Separated Lamellae In Semi-Crystalline Diblock Copolymer Comprising Polyethylene And Atactic Polypropylene Blocks, William Macknight, Masaya Ueda, Kazuo Sakurai, Shigeru Okamoto, David J. Lohse, Seiji Shinkai, Shinichi Sakurai, Shunji Nomura

William MacKnight

No abstract provided.

Performance Limits Of Track-To-Track Fusion Vs. Centralized Estimation: Theory And Application, Huimin Chen, T K. Kirubarajan, Yaakov Bar-Shalom

Huimin Chen

No abstract provided.

The Genesis Of Swarm Engineering, S. Kazadi

Sanza Kazadi

A Survey Of Reservation Schemes For Optical Burst Switching (Obs), Ioannis Karamitsos, Evangelos Varthis

John P. Karamitsos

No abstract provided.