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Final report

Description: High performance computational science and engineering simulations have become an increasingly important part of the scientist's problem solving toolset. A key reason is the development of widely used codes and libraries that support these applications, for example, Netlib, a collection of numerical libraries [33]. The term community codes refers to those libraries or applications that have achieved some critical level of acceptance by a user community. Many of these applications are on the high-end in terms of required resources: computation, storage, and communication. Recently, there has been considerable interest in putting such applications on-line and packaging them as network services to make them available to a wider user base. Applications such as data mining [22], theorem proving and logic [14], parallel numerical computation [8][32] are example services that are all going on-line. Transforming applications into services has been made possible by advances in packaging and interface technologies including component systems [2][6][13][28][37], proposed communication standards [34], and newer Web technologies such as Web Services [38]. Network services allow the user to focus on their application and obtain remote service when needed by simply invoking the service across the network. The user can be assured that the most recent version of the code or service is always provided and they do not need to install, maintain, and manage significant infrastructure to access the service. For high performance applications in particular, the user is still often required to install a code base (e.g. MPI), and therefore become involved with the tedious details of infrastructure management. In the network service model, the service provider is responsible for all of these activities and not the user. The user need not become an expert in high performance computing. An additional advantage of high-end network services is that the user need not have specialized computational resources in ...
Date: April 30, 2006
Creator: Weissman, Jon B
Partner: UNT Libraries Government Documents Department

Solar Thermochemical Fuels Production: Solar Fuels via Partial Redox Cycles with Heat Recovery

Description: HEATS Project: The University of Minnesota is developing a solar thermochemical reactor that will efficiently produce fuel from sunlight, using solar energy to produce heat to break chemical bonds. The University of Minnesota is envisioning producing the fuel by using partial redox cycles and ceria-based reactive materials. The team will achieve unprecedented solar-to-fuel conversion efficiencies of more than 10% (where current state-of-the-art efficiency is 1%) by combined efforts and innovations in material development, and reactor design with effective heat recovery mechanisms and demonstration. This new technology will allow for the effective use of vast domestic solar resources to produce precursors to synthetic fuels that could replace gasoline.
Date: December 19, 2011
Partner: UNT Libraries Government Documents Department

Yield Improvement and Energy Savings Uing Phosphonates as Additives in Kraft pulping

Description: Project Objective: Develop a commercially viable modification to the Kraft process resulting in energy savings, increased yield and improved bleachability. Evaluate the feasibility of this technology across a spectrum of wood species used in North America. Develop detailed fundamental understanding of the mechanism by which phosphonates improve KAPPA number and yield. Evaluate the North American market potential for the use of phosphonates in the Kraft pulping process. Examine determinants of customer perceived value and explore organizational and operational factors influencing attitudes and behaviors. Provide an economic feasibility assessment for the supply chain, both suppliers (chemical supply companies) and buyers (Kraft mills). Provide background to most effectively transfer this new technology to commercial mills.
Date: March 31, 2007
Creator: Tschirner, Ulrike W. & Smith, Timothy
Partner: UNT Libraries Government Documents Department

3-D Characterization of the Structure of Paper and Paperboard and Their Application to Optimize Drying and Water Removal Processes and End-Use Applications

Description: The three dimensional structure of paper materials plays a critical role in the paper manufacturing process especially via its impact on the transport properties for fluids. Dewatering of the wet web, pressing and drying will benefit from knowledge of the relationships between the web structure and its transport coefficients. The structure of the pore space within a paper sheet is imaged in serial sections using x-ray micro computed tomography. The three dimensional structure is reconstructed from these sections using digital image processing techniques. The structure is then analyzed by measuring traditional descriptors for the pore space such as specific surface area and porosity. A sequence of microtomographs was imaged at approximately 2 m intervals and the three-dimensional pore-fiber structure was reconstructed. The pore size distributions for both in-plane as well as transverse pores were measured. Significant differences in the in-plane (XY) and the transverse directions in pore characteristics are found and may help partly explain the different liquid and vapor transport properties in the in-plane and transverse directions. Results with varying sheet structures compare favorably with conventional mercury intrusion porosimetry data. Interestingly, the transverse pore structure appears to be more open with larger pore size distribution compared to the in plane pore structure. This may help explain the differences in liquid and vapor transport through the in plane and transverse structures during the paper manufacturing process and during end-use application. Comparison of Z-directional structural details of hand sheet and commercially made fine paper samples show a distinct difference in pore size distribution both in the in-plane and transverse direction. Method presented here may provide a useful tool to the papermaker to truly engineer the structure of paper and board tailored to specific end-use applications. The difference in surface structure between the top and bottom sides of the porous material, i.e. ...
Date: August 29, 2004
Creator: Shri Ramaswamy, University of Minnesota & B.V. Ramarao, State University of New York
Partner: UNT Libraries Government Documents Department

Program Abstracts: Formation and Growth of Atmospheric Aerosols

Description: DOE provided $11,000 to sponsor the Workshop on New Particle Formation in the Atmosphere, which was held at The Riverwood Inn and Conference Center near Minneapolis, MN from September 7 to 9, 2006. Recent work has shown that new particle formation is an important atmospheric process that must be better understood due to its impact on cloud cover and the Earth's radiation balance. The conference was an informal gathering of atmospheric and basic scientists with expertise pertinent to this topic. The workshop included discussions of: • atmospheric modeling; • computational chemistry pertinent to clustering; • ions and ion induced nucleation; • basic laboratory and theoretical studies of nucleation; • studies on neutral molecular clusters; • interactions of organic compounds and sulfuric acid; • composition of freshly nucleated particles. Fifty six scientists attended the conference. They included 27 senior scientists, 9 younger independent scientists (assistant professor or young associate professor level), 7 postdocs, 13 graduate students, 10 women, 35 North Americans (34 from the U.S.), 1 Asian, and 20 Europeans. This was an excellent informal workshop on an important topic. An effort was made to include individuals from communities that do not regularly interact. A number of participants have provided informal feedback indicating that the workshop led to research ideas and possible future collaborations.
Date: September 7, 2006
Creator: McMurry, Peter H. & Kulmala, Markku
Partner: UNT Libraries Government Documents Department

Technical Report: Investigation of Carbon Cycle Processes within a Managed Landscape: An Ecosystem Manipulation and Isotope Tracer Approach

Description: The goal of this research is to provide a better scientific understanding of carbon cycle processes within an agricultural landscape characteristic of the Upper Midwest. This project recognizes the need to study processes at multiple spatial and temporal scales to reduce uncertainty in ecosystem and landscape-scale carbon budgets to provide a sound basis for shaping future policy related to carbon management. Specifically, this project has attempted to answer the following questions: 1. Would the use of cover crops result in a shift from carbon neutral to significant carbon gain in corn-soybean rotation ecosystems of the Upper Midwest? 2. Can stable carbon isotope analyses be used to partition ecosystem respiration into its autotrophic and heterotrophic components? 3. Can this partitioning be used to better understand the fate of crop residues to project changes in the soil carbon reservoir? 4. Are agricultural ecosystems of the Upper Midwest carbon neutral, sinks, or sources? Can the proposed measurement and modeling framework help address landscape-scale carbon budget uncertainties and help guide future carbon management policy?
Date: June 1, 2009
Creator: Griffis, Timothy J; Baker, John M & Billmark, Kaycie
Partner: UNT Libraries Government Documents Department

Autothermal Reforming of Renewable Fuels

Description: The conversion of biomass into energy and chemicals is a major research and technology challenge of this century, comparable to petroleum processing in the last century. Recently we have successfully transformed both volatile liquids and nonvolatile liquids and solids into syngas with no carbon formation in autothermal catalytic reactors with residence times of ~10 milliseconds. In the proposed research program we explore the mechanisms of these processes and their extensions to other biomass sources and applications by examining different feeds, catalysts, flow conditions, and steam addition to maximize production of either syngas or chemicals. We will systematically study the catalytic partial oxidation in millisecond autothermal reactors of solid biomass and the liquid products formed by pyrolysis of solid biomass. We will examine alcohols, polyols, esters, solid carbohydrates, and lignocellulose to try to maximize formation of either hydrogen and syngas or olefins and oxygenated chemicals. We will explore molecules and mixtures of practical interest as well as surrogate molecules that contain the functional groups of biofuels but are simpler to analyze and interpret. We will examine spatial profiles within the catalyst and transient and periodic operation of these reactors at pressures up to 10 atm to obtain data from which to explore more detailed mechanistic models and optimize performance to produce a specific desired product. New experiments will examine the conversion of syngas into biofuels such as methanol and dimethyl ether to explore the entire process of producing biofuels from biomass in small distributed systems. Experiments and modeling will be integrated to probe and understand detailed reaction kinetics and the processes by which solid biomass particles are transformed into syngas and chemicals by reactive flash volatilization.
Date: May 1, 2009
Creator: Schmidt, Lanny D
Partner: UNT Libraries Government Documents Department

Final Report DE-FG02-00ER54583: "Physics of Atmospheric Pressure Glow Discharges" and "Nanoparticle Nucleation and Dynamics in Low-Pressure Plasmas"

Description: This project was funded over two periods of three years each, with an additional year of no-cost extension. Research in the first funding period focused on the physics of uniform atmospheric pressure glow discharges, the second funding period was devoted to the study of the dynamics of nanometer-sized particles in plasmas.
Date: June 1, 2009
Creator: Kortshagen, Uwe; Heberlein, Joachim & Girshick, Steven L.
Partner: UNT Libraries Government Documents Department

Modification of Thermal Emission via Metallic Photonic Crystals

Description: Photonic crystals are materials that are periodically structured on an optical length scale. It was previously demonstrated that the glow, or thermal emission, of tungsten photonic crystals that have a specific structure - known as the 'woodpile structure' - could be modified to reduce the amount of infrared radiation from the material. This ability has implications for improving the efficiency of thermal emission sources and for thermophotovoltaic devices. The study of this effect had been limited because the fabrication of metallic woodpile structures had previously required a complex fabrication process. In this project we pursued several approaches to simplify the fabrication of metallic photonic crystals that are useful for modification of thermal emission. First, we used the self-assembly of micrometer-scale spheres into colloidal crystals known as synthetic opals. These opals can then be infiltrated with a metal and the spheres removed to obtain a structure, known as an inverse opal, in which a three-dimensional array of bubbles is embedded in a film. Second, we used direct laser writing, in which the focus of an infrared laser is moved through a thin film of photoresist to form lines by multiphoton polymerization. Proper layering of such lines can lead to a scaffold with the woodpile structure, which can be coated with a refractory metal. Third, we explored a completely new approach to modified thermal emission - thin metal foils that contain a simple periodic surface pattern, as shown in Fig. 1. When such a foil is heated, surface plasmons are excited that propagate along the metal interface. If these waves strike the pattern, they can be converted into thermal emission with specific properties.
Date: July 30, 2012
Creator: Norris, David J.; Stein, Andreas & George, Steven M.
Partner: UNT Libraries Government Documents Department

Advanced Energy Efficient Roof System

Description: Energy consumption in buildings represents 40 percent of primary U.S. energy consumption, split almost equally between residential (22%) and commercial (18%) buildings.1 Space heating (31%) and cooling (12%) account for approximately 9 quadrillion Btu. Improvements in the building envelope can have a significant impact on reducing energy consumption. Thermal losses (or gains) from the roof make up 14 percent of the building component energy load. Infiltration through the building envelope, including the roof, accounts for an additional 28 percent of the heating loads and 16 percent of the cooling loads. These figures provide a strong incentive to develop and implement more energy efficient roof systems. The roof is perhaps the most challenging component of the building envelope to change for many reasons. The engineered roof truss, which has been around since 1956, is relatively low cost and is the industry standard. The roof has multiple functions. A typical wood frame home lasts a long time. Building codes vary across the country. Customer and trade acceptance of new building products and materials may impede market penetration. The energy savings of a new roof system must be balanced with other requirements such as first and life-cycle costs, durability, appearance, and ease of construction. Conventional residential roof construction utilizes closely spaced roof trusses supporting a layer of sheathing and roofing materials. Gypsum board is typically attached to the lower chord of the trusses forming the finished ceiling for the occupied space. Often in warmer climates, the HVAC system and ducts are placed in the unconditioned and otherwise unusable attic. High temperature differentials and leaky ducts result in thermal losses. Penetrations through the ceilings are notoriously difficult to seal and lead to moisture and air infiltration. These issues all contribute to greater energy use and have led builders to consider construction of a conditioned ...
Date: September 30, 2008
Creator: Davidson, Jane
Partner: UNT Libraries Government Documents Department

A New Concept for the Fabrication of Hydrogen Selective Silica Membranes

Description: It was proposed to investigate a new concept for the synthesis of molecular sieve hydrogen selective membranes. This concept is based on the use of exfoliated layered zeolite precursors in coating processes to make nanocomposite films with inorganic or polymeric matrices. We discovered that creating exfoliated zeolite layers was much more difficult than anticipated because the methods originally proposed (based on existing literature reports) were not successful in providing exfoliated layers while preserving their porous structure. Although the original goals of fabricating high-selectivity-high-flux membranes that are stable under conditions present in a water-gas-shift reactor and that are able to selectively permeate hydrogen over all other components of the mixtures present in these reactors were not accomplished fully, significant progress has been made as follows: (1) Proof-of-concept hydrogen-selective nanocomposite membranes have been fabricated; (2) Methods to exfoliate layered zeolite precursors preserving the layer structure were identified; and (3) Unexpectedly, membranes exhibiting high ideal selectivity for carbon dioxide over nitrogen at room temperature were produced. The findings listed above provide confidence that the proposed novel concept can eventually be realized.
Date: January 7, 2009
Creator: Tsapatsis, Michael
Partner: UNT Libraries Government Documents Department

A New Concept for the Fabrication of Hydrogen Selective Silica Membranes

Description: We are attempting to fabricate H{sub 2}-selective silica-based films by ''layer-by-layer'' deposition as a new approach for thin films. A sonication-assisted deposition method was mainly used for ''layer-by-layer'' deposition. In addition, other approaches such as a dip-coating and the use of a polymer matrix with a layered silicate were contrived as well. This report shows the progress done during the 2nd Year of this award.
Date: July 31, 2006
Creator: Tsapatsis, Michael
Partner: UNT Libraries Government Documents Department

Electron Coherence in Mesoscopic Structures

Description: The recent rapid progress in nanofabrication and experimental techniques made it possible to investigate a variety of meso-- and nano--scale systems, which were unavailable only a few years ago. Examples include fabrication of high-quality quantum wires in semiconductor heterostructures, of nanoscale hybrid superconductor--normal metal structures, and of a variety of novel (and much smaller) quantum dot and q-bit designs. These technological advances have led to formulation of a number of condensed matter theory problems which are equally important for applications and for the fundamental science. The present proposal aims at filling the exposed gaps in knowledge and at facilitating further development of experimental and theoretical physics of nanoscale structures. Specifically, the two PIs address the following issues: (i) The theory of interacting electrons in a quantum wire which accounts adequately for the non-linear dispersion relation of the electrons. The existing approaches rely on models with {\em linearized} electron spectrum, which fall short of addressing a growing list of experimentally relevant phenomena. (ii) Dynamics of hybrid normal--superconducting systems. A reliable treatment of dissipative phenomena in such structures is not developed as of yet, while rapid progress in fabrication makes finding the proper theoretical treatment methods highly desirable. (iii)~The fundamental limits on relaxation times of a superconducting charge q-bit. The latter is one of the most advanced scalable realizations of a quantum computing device. (iv)~The dynamics and relaxation times of a spin of an electron in a small semiconductor quantum dot. Besides the fundamental importance, these structures are also valuable candidates for quantum computing applications.
Date: March 20, 2011
Creator: Kamenev, Alex & Glazman, Leonid
Partner: UNT Libraries Government Documents Department

Technical Report: Impacts of Land Management and Climate on Agroecosystem Greenhouse Gas Exchange in the Upper Midwest United States

Description: Our research is designed to improve the scientific understanding of how carbon is cycled between the land and atmosphere within a heavily managed landscape that is characteristic of the Upper Midwest. The Objectives are: 1) Quantify the seasonal and interannual variation of net ecosystem CO2 exchange of agricultural ecosystems in the Upper Midwest grown under different management strategies; 2) Partition net ecosystem CO2 exchange into photosynthesis and ecosystem respiration by combining micrometeorological and stable isotope techniques; 3) Examine the seasonal variation in canopy-scale photosynthetic discrimination and the isotope ratios of ecosystem respiration and photosynthesis.
Date: July 1, 2007
Creator: Griffis, Timothy J. & Baker, John M.
Partner: UNT Libraries Government Documents Department

Metabolic regulation of the plant hormone indole-3-acetic acid

Description: The phytohormone indole-3-acetic acid (IAA, auxin) is important for many aspects of plant growth, development and responses to the environment yet the routes to is biosynthesis and mechanisms for regulation of IAA levels remain important research questions. A critical issue concerning the biosynthesis if IAA in plants is that redundant pathways for IAA biosynthesis exist in plants. We showed that these redundant pathways and their relative contribution to net IAA production are under both developmental and environmental control. We worked on three fundamental problems related to how plants get their IAA: 1) An in vitro biochemical approach was used to define the tryptophan dependent pathway to IAA using maize endosperm, where relatively large amounts of IAA are produced over a short developmental period. Both a stable isotope dilution and a protein MS approach were used to identify intermediates and enzymes in the reactions. 2) We developed an in vitro system for analysis of tryptophan-independent IAA biosynthesis in maize seedlings and we used a metabolite profiling approach to isolate intermediates in this reaction. 3) Arabidopsis contains a small family of genes that encode potential indolepyruvate decarboxylase enzymes. We cloned these genes and studied plants that are mutant in these genes and that over-express each member in the family in terms of the level and route of IAA biosynthesis. Together, these allowed further development of a comprehensive picture of the pathways and regulatory components that are involved in IAA homeostasis in higher plants.
Date: November 1, 2009
Creator: Cohen, Jerry D.
Partner: UNT Libraries Government Documents Department

Functional Analysis of Arabidopsis Sucrose Transporters

Description: Sucrose is the main photosynthetic product that is transported in the vasculature of plants. The long-distance transport of carbohydrates is required to support the growth and development of net-importing (sink) tissues such as fruit, seeds and roots. This project is focused on understanding the transport mechanism sucrose transporters (SUTs). These are proton-coupled sucrose uptake transporters (membrane proteins) that are required for transport of sucrose in the vasculature and uptake into sink tissues. The accomplishments of this project included: 1) the first analysis of substrate specificity for any SUT. This was accomplished using electrophysiology to analyze AtSUC2, a sucrose transporter from companion cells in Arabidopsis. 2) the first analysis of the transport activity for a monocot SUT. The transport kinetics and substrate specificity of HvSUT1 from barley were studied. 3) the first analysis of a sucrose transporter from sugarcane. and 4) the first analysis of transport activity of a sugar alcohol transporter homolog from plants, AtPLT5. During this period four primary research papers, funded directly by the project, were published in refereed journals. The characterization of several sucrose transporters was essential for the current effort in the analysis of structure/function for this gene family. In particular, the demonstration of strong differences in substrate specificity between type I and II SUTs was important to identify targets for site-directed mutagenesis.
Date: March 31, 2009
Creator: Ward, John M.
Partner: UNT Libraries Government Documents Department

A Theoretical Study of the Transient Operation and Stability of Two-Phase Natural Circulation Loops

Description: Mathematical models of the time-dependent behavior of two-phase natural- circulation loops were used to predict the operation and to explain the unusual instability sometimes observed. The initial results obtained for a loop similar to the Univ. of Minnesota loop were used to formulate a more complex and accurate model, and the predicted transient behavior was in close agreement with the experimental results from the Minnesota loop. For a 300psia, high-pressure loop, unstable oscillatory behavior was predicted under certain conditions and stable behavior under others. Closed unstable regions rather than limits were predicted, and the specifications of stability in terms of a single parameter were found to be impossible. The great difference in oscillatory frequencies observed at low and high pressures was found to be due largely to the system geometry. The criterion for the absence of oscillations was found to be similar to one of the criteria for stability of chemical reaction systems. (D.L.C.)
Date: June 1, 1961
Creator: Garlid, K.; Amundson, N. R. & Isbin, H. S.
Partner: UNT Libraries Government Documents Department