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Gelled Ionic Liquid-Based Membranes

Description: Advanced Research Projects Agency-Energy project sheet summarizing general information about the Innovative Materials and Processes for Advanced Carbon Capture Technologies (IMPACCT) program including critical needs, innovation and advantages, impacts, and contact information. This sheet discusses the development of gelled membranes as part of the "Achieving a 10,000 GPU Permeance for Post-Combustion Carbon Capture with Gelled Ionic Liquid-Based Membranes" project.
Date: May 25, 2012
Creator: University of Colorado Boulder
Partner: UNT Libraries Government Documents Department

Integrated Solar Power Converters

Description: Advanced Research Projects Agency-Energy project sheet summarizing general information about the Agile Delivery of Electrical Power Technology (ADEPT) program including critical needs, innovation and advantages, impacts, and contact information. This sheet discusses more efficient solar panel power converters as part of the "Wafer-Level Sub-Module Integrated DC/DC Converter" project.
Date: June 4, 2012
Creator: University of Colorado Boulder
Partner: UNT Libraries Government Documents Department

Covalently crosslinked diels-alder polymer networks.

Description: This project examines the utility of cycloaddition reactions for the synthesis of polymer networks. Cycloaddition reactions are desirable because they produce no unwanted side reactions or small molecules, allowing for the formation of high molecular weight species and glassy crosslinked networks. Both the Diels-Alder reaction and the copper-catalyzed azide-alkyne cycloaddition (CuAAC) were studied. Accomplishments include externally triggered healing of a thermoreversible covalent network via self-limited hysteresis heating, the creation of Diels-Alder based photoresists, and the successful photochemical catalysis of CuAAC as an alternative to the use of ascorbic acid for the generation of Cu(I) in click reactions. An analysis of the results reveals that these new methods offer the promise of efficiently creating robust, high molecular weight species and delicate three dimensional structures that incorporate chemical functionality in the patterned material. This work was performed under a Strategic Partnerships LDRD during FY10 and FY11 as part of a Sandia National Laboratories/University of Colorado-Boulder Excellence in Science and Engineering Fellowship awarded to Brian J. Adzima, a graduate student at UC-Boulder. Benjamin J. Anderson (Org. 1833) was the Sandia National Laboratories point-of-contact for this fellowship.
Date: September 1, 2011
Creator: Bowman, Christopher (University of Colorado, Boulder, CO); Adzima, Brian J. (University of Colorado, Boulder, CO) & Anderson, Benjamin John
Partner: UNT Libraries Government Documents Department

Atomistic modeling of nanowires, small-scale fatigue damage in cast magnesium, and materials for MEMS.

Description: Lightweight and miniaturized weapon systems are driving the use of new materials in design such as microscale materials and ultra low-density metallic materials. Reliable design of future weapon components and systems demands a thorough understanding of the deformation modes in these materials that comprise the components and a robust methodology to predict their performance during service or storage. Traditional continuum models of material deformation and failure are not easily extended to these new materials unless microstructural characteristics are included in the formulation. For example, in LIGA Ni and Al-Si thin films, the physical size is on the order of microns, a scale approaching key microstructural features. For a new potential structural material, cast Mg offers a high stiffness-to-weight ratio, but the microstructural heterogeneity at various scales requires a structure-property continuum model. Processes occurring at the nanoscale and microscale develop certain structures that drive material behavior. The objective of the work presented in this report was to understand material characteristics in relation to mechanical properties at the nanoscale and microscale in these promising new material systems. Research was conducted primarily at the University of Colorado at Boulder to employ tightly coupled experimentation and simulation to study damage at various material size scales under monotonic and cyclic loading conditions. Experimental characterization of nano/micro damage will be accomplished by novel techniques such as in-situ environmental scanning electron microscopy (ESEM), 1 MeV transmission electron microscopy (TEM), and atomic force microscopy (AFM). New simulations to support experimental efforts will include modified embedded atom method (MEAM) atomistic simulations at the nanoscale and single crystal micromechanical finite element simulations. This report summarizes the major research and development accomplishments for the LDRD project titled 'Atomistic Modeling of Nanowires, Small-scale Fatigue Damage in Cast Magnesium, and Materials for MEMS'. This project supported a strategic partnership between Sandia National Laboratories ...
Date: October 1, 2006
Creator: Dunn, Martin L. (University of Colorado, Boulder, CO); Talmage, Mellisa J. (University of Colorado, Boulder, CO); McDowell, David L., 1956- (,-Georgia Institute of Technology, Atlanta, GA); West, Neil (University of Colorado, Boulder, CO); Gullett, Philip Michael (Mississippi State University , MS); Miller, David C. (University of Colorado, Boulder, CO) et al.
Partner: UNT Libraries Government Documents Department

Modeling and design optimization of adhesion between surfaces at the microscale.

Description: This research applies design optimization techniques to structures in adhesive contact where the dominant adhesive mechanism is the van der Waals force. Interface finite elements are developed for domains discretized by beam elements, quadrilateral elements or triangular shell elements. Example analysis problems comparing finite element results to analytical solutions are presented. These examples are then optimized, where the objective is matching a force-displacement relationship and the optimization variables are the interface element energy of adhesion or the width of beam elements in the structure. Several parameter studies are conducted and discussed.
Date: August 1, 2008
Creator: Sylves, Kevin T. (University of Colorado, Boulder, CO)
Partner: UNT Libraries Government Documents Department

Novel modified zeolites for energy-efficient hydrocarbon separations.

Description: We present synthesis, characterization and testing results of our applied research project, which focuses on the effects of surface and skeletal modification of zeolites for significant enhancements in current hydrocarbon (HC) separations. Zeolites are commonly used by the chemical and petroleum industries as catalysts and ion-exchangers. They have high potential for separations owing to their unique pore structures and adsorption properties and their thermal, mechanical and chemical properties. Because of zeolites separation properties, low cost, and robustness in industrial process, they are natural choice for use as industrial adsorbents. This is a multidisciplinary effort to research, design, develop, engineer, and test new and improved materials for the separation of branched vs. linear organic molecules found in commercially important HC streams via adsorption based separations. The focus of this project was the surface and framework modification of the commercially available zeolites, while tuning the adsorption properties and the selectivities of the bulk and membrane separations. In particular, we are interested with our partners at Goodyear Chemical, on how to apply the modified zeolites to feedstock isoprene purification. For the characterization and the property measurements of the new and improved materials powder X-ray diffraction (PXRD), Residual Gas Analyzer-Mass Spectroscopy (RGA-MS), Electron Microscopy (SEM/EDAX), temperature programmed desorption (TPD) and surface area techniques were utilized. In-situ carbonization of MFI zeolite membranes allowed for the maximum separation of isoprene from n-pentane, with a 4.1% enrichment of the binary stream with n-pentane. In four component streams, a modified MFI membrane had high selectivities for n-pentane and 1-3-pentadiene over isoprene but virtually no separation for the 2-methyl-2-butene/isoprene pair.
Date: November 1, 2006
Creator: Arruebo, Manuel (University of Colorado, Boulder, CO); Dong, Junhang; Anderson, Thomas (Burns and McDonnell, Kansas City, MO); Gu, Xuehong; Gray, Gary (Goodyear Chemical Company, Akron, OH); Bennett, Ron (Goodyear Chemical Company, Akron, OH) et al.
Partner: UNT Libraries Government Documents Department

Modeling brittle fracture, slip weakening, and variable friction in geomaterials with an embedded strong discontinuity finite element.

Description: Localized shear deformation plays an important role in a number of geotechnical and geological processes. Slope failures, the formation and propagation of faults, cracking in concrete dams, and shear fractures in subsiding hydrocarbon reservoirs are examples of important effects of shear localization. Traditional engineering analyses of these phenomena, such as limit equilibrium techniques, make certain assumptions on the shape of the failure surface as well as other simplifications. While these methods may be adequate for the applications for which they were designed, it is difficult to extrapolate the results to more general scenarios. An alternative approach is to use a numerical modeling technique, such as the finite element method, to predict localization. While standard finite elements can model a wide variety of loading situations and geometries quite well, for numerical reasons they have difficulty capturing the softening and anisotropic damage that accompanies localization. By introducing an enhancement to the element in the form of a fracture surface at an arbitrary position and orientation in the element, we can regularize the solution, model the weakening response, and track the relative motion of the surfaces. To properly model the slip along these surfaces, the traction-displacement response must be properly captured. This report focuses on the development of a constitutive model appropriate to localizing geomaterials, and the embedding of this model into the enhanced finite element framework. This modeling covers two distinct phases. The first, usually brief, phase is the weakening response as the material transitions from intact continuum to a body with a cohesionless fractured surface. Once the cohesion has been eliminated, the response along the surface is completely frictional. We have focused on a rate- and state-dependent frictional model that captures stable and unstable slip along the surface. This model is embedded numerically into the element using a generalized trapezoidal formulation. ...
Date: October 1, 2006
Creator: Regueiro, Richard A. (University of Colorado, Boulder, CO); Borja, R. I. (Stanford University, Stanford, CA) & Foster, C. D. (Stanford University, Stanford, CA)
Partner: UNT Libraries Government Documents Department

On the formulation, parameter identification and numerical integration of the EMMI model :plasticity and isotropic damage.

Description: In this report we present the formulation of the physically-based Evolving Microstructural Model of Inelasticity (EMMI) . The specific version of the model treated here describes the plasticity and isotropic damage of metals as being currently applied to model the ductile failure process in structural components of the W80 program . The formulation of the EMMI constitutive equations is framed in the context of the large deformation kinematics of solids and the thermodynamics of internal state variables . This formulation is focused first on developing the plasticity equations in both the relaxed (unloaded) and current configurations. The equations in the current configuration, expressed in non-dimensional form, are used to devise the identification procedure for the plasticity parameters. The model is then extended to include a porosity-based isotropic damage state variable to describe the progressive deterioration of the strength and mechanical properties of metals induced by deformation . The numerical treatment of these coupled plasticity-damage constitutive equations is explained in detail. A number of examples are solved to validate the numerical implementation of the model.
Date: January 1, 2006
Creator: Bammann, Douglas J.; Johnson, G. C. (University of California, Berkeley, CA); Marin, Esteban B. & Regueiro, Richard A. (University of Colorado, Boulder, CO)
Partner: UNT Libraries Government Documents Department

Intrusion detection and monitoring for wireless networks.

Description: Wireless computer networks are increasing exponentially around the world. They are being implemented in both the unlicensed radio frequency (RF) spectrum (IEEE 802.11a/b/g) and the licensed spectrum (e.g., Firetide [1] and Motorola Canopy [2]). Wireless networks operating in the unlicensed spectrum are by far the most popular wireless computer networks in existence. The open (i.e., proprietary) nature of the IEEE 802.11 protocols and the availability of ''free'' RF spectrum have encouraged many producers of enterprise and common off-the-shelf (COTS) computer networking equipment to jump into the wireless arena. Competition between these companies has driven down the price of 802.11 wireless networking equipment and has improved user experiences with such equipment. The end result has been an increased adoption of the equipment by businesses and consumers, the establishment of the Wi-Fi Alliance [3], and widespread use of the Alliance's ''Wi-Fi'' moniker to describe these networks. Consumers use 802.11 equipment at home to reduce the burden of running wires in existing construction, facilitate the sharing of broadband Internet services with roommates or neighbors, and increase their range of ''connectedness''. Private businesses and government entities (at all levels) are deploying wireless networks to reduce wiring costs, increase employee mobility, enable non-employees to access the Internet, and create an added revenue stream to their existing business models (coffee houses, airports, hotels, etc.). Municipalities (Philadelphia; San Francisco; Grand Haven, MI) are deploying wireless networks so they can bring broadband Internet access to places lacking such access; offer limited-speed broadband access to impoverished communities; offer broadband in places, such as marinas and state parks, that are passed over by traditional broadband providers; and provide themselves with higher quality, more complete network coverage for use by emergency responders and other municipal agencies. In short, these Wi-Fi networks are being deployed everywhere. Much thought has been and is ...
Date: November 1, 2005
Creator: Thomas, Eric D.; Van Randwyk, Jamie A.; Lee, Erik J.; Stephano, Amanda (Indiana University); Tabriz, Parisa (University of Illinois at Urbana-Champaign); Pelon, Kristen (Cedarville University) et al.
Partner: UNT Libraries Government Documents Department

Status and Plans for the National Spherical Torus Experimental Research Facility

Description: An overview of the research capabilities and the future plans on the MA-class National Spherical Torus Experiment (NSTX) at Princeton is presented. NSTX research is exploring the scientific benefits of modifying the field line structure from that in more conventional aspect ratio devices, such as the tokamak. The relevant scientific issues pursued on NSTX include energy confinement, MHD stability at high beta, non-inductive sustainment, solenoid-free start-up, and power and particle handling. In support of the NSTX research goal, research tools are being developed by the NSTX team. In the context of the fusion energy development path being formulated in the US, an ST-based Component Test Facility (CTF) and, ultimately a high beta Demo device based on the ST, are being considered. For these, it is essential to develop high performance (high beta and high confinement), steady-state (non-inductively driven) ST operational scenarios and an efficient solenoid-free start-up concept. We will also briefly describe the Next-Step-ST (NSST) device being designed to address these issues in fusion-relevant plasma conditions.
Date: July 27, 2005
Creator: Columbia University
Partner: UNT Libraries Government Documents Department