Solar Energy Windows and Smart IR Switchable Building Technologies (open access)

Solar Energy Windows and Smart IR Switchable Building Technologies

The three building envelope functions with the largest impact on the energy usage are illumination, energy flux and energy production. In general, these three functions are addressed separately in the building design. A step change toward a zero-energy building can be achieved with a glazing system that combines these three functions and their control into a single unit. In particular, significant value could be realized if illumination into the building is dynamically controlled such that it occurs during periods of low load on the grid (e.g., morning) to augment illumination supplied by interior lights and then to have that same light diverted to PV energy production and the thermal energy rejected during periods of high load on the grid. The objective of this project is to investigate the feasibility of a glazing unit design that integrates these three key functions (illumination and energy flux control, and power production) into a single module.
Date: September 30, 2011
Creator: McCarny, James & Kornish, Brian
Object Type: Report
System: The UNT Digital Library
A Meta-Analysis of Energy Savings from Lighting Controls in Commercial Buildings (open access)

A Meta-Analysis of Energy Savings from Lighting Controls in Commercial Buildings

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Date: September 2, 2011
Creator: Williams, Alison; Atkinson, Barbara; Garbesi, Karina; Rubinstein, Francis & Page, Erik
Object Type: Article
System: The UNT Digital Library
Liquid-Water Uptake and Removal in PEM Fuel-Cell Components (open access)

Liquid-Water Uptake and Removal in PEM Fuel-Cell Components

Management of liquid water is critical for optimal fuel-cell operation, especially at low temperatures. It is therefore important to understand the wetting properties and water holdup of the various fuel-cell layers. While the gas-diffusion layer is relatively hydrophobic and exhibits a strong intermediate wettability, the catalyst layer is predominantly hydrophilic. In addition, the water content of the ionomer in the catalyst layer is lower than that of the bulk membrane, and is affected by platinum surfaces. Liquid-water removal occurs through droplets on the surface of the gas-diffusion layer. In order to predict droplet instability and detachment, a force balance is used. While the pressure or drag force on the droplet can be derived, the adhesion or surface-tension force requires measurement using a sliding-angle approach. It is shown that droplets produced by forcing water through the gas-diffusion layer rather than placing them on top of it show much stronger adhesion forces owing to the contact to the subsurface water.
Date: September 23, 2011
Creator: Das, Prodip K.; Gunterman, Haluna P.; Kwong, Anthony & Weber, Adam Z.
Object Type: Article
System: The UNT Digital Library
Survey of nucleon electromagnetic form factors (open access)

Survey of nucleon electromagnetic form factors

There has been much activity in the measurement of the elastic electromagnetic proton and neutron form factors in the last decade, and the quality of the data has been greatly improved by performing double polarization experiments, in compar- ison with previous unpolarized data. Here we review the experimental data base in view of the new results for the proton, and neutron, obtained at MIT-Bates, MAMI, and JLab. The rapid evolution of phenomenological models triggered by these high-precision experiments will be discussed.
Date: September 20, 2011
Creator: Perdrisat, Charles F. & Punjabi, Vina A.
Object Type: Article
System: The UNT Digital Library
Effect of MgO Additive on Volumetric Expansion of Self-Degradable Cements (open access)

Effect of MgO Additive on Volumetric Expansion of Self-Degradable Cements

We identified hard-burned magnesium oxide (MgO) as a suitable expansive additive for improving the plugging performance of self-degradable, temporary sodium silicate-activated slag/Class C fly ash (SSASC) blend cement sealers into rock fractures in Enhanced Geothermal Systems (EGSs). MgO extended the volumetric expansion of sealers during their exposure to a hydrothermal environment at 200 C under pressures, ranging from 300 to 1500 psi. A great expansion ratc of 19.3% was observed by adding 3.0 wt% MgO under 300 psi pressure, thus promising to plug thoroughly inner fracture. When the pressure was increased from 300 psi to 1500 psi, the expansion rate of cement markedly reduced, corresponding to the formaLion of crack-free specimens and the improvement of compressive strength. However, with 3.0 wt% MgO, the specimens still engendered the generation of numerous visual cracks, although they were prepared under a high pressure of 1500 psi. The effective content of MgO in minimizing and eliminating the generation of cracks was 2.0 wt%, which provided a moderate expansion of {ge} 0.5%. The compressive strength of 2.0 wt% MgO specimens made under a pressure of 300 psi rose {approx} 1.7-fold to 4816 psi with an increasing pressure to 1500 psi. The in-situ growth of brucite …
Date: September 30, 2011
Creator: Sugama, T.; Warren, J. & Butcher, T.
Object Type: Report
System: The UNT Digital Library
Numerical and Experimental Study of Mixing Processes Associated with Hydrogen and High Hydrogen Content Fuels (open access)

Numerical and Experimental Study of Mixing Processes Associated with Hydrogen and High Hydrogen Content Fuels

As simulation capability improves exponentially with increasingly more cost effective CPUs and hardware, it can be used ?routinely? for engineering applications. Many commercial products are available and they are marketed as increasingly powerful and easy to use. The question remains as to the overall accuracy of results obtained. To support the validation of the CFD, a hierarchical experiment was established in which the type of fuel injection (radial, axial) as well as level of swirl (non-swirling, swirling) could be systematically varied. The effort was limited to time efficient approaches (i.e., generally RANS approaches) although limited assessment of time resolved methods (i.e., unsteady RANS and LES) were considered. Careful measurements of the flowfield velocity and fuel concentration were made using both intrusive and non-intrusive methods. This database was then used as the basis for the assessment of the CFD approach. The numerical studies were carried out with a statistically based matrix. As a result, the effect of turbulence model, fuel type, axial plane, turbulent Schmidt number, and injection type could be studied using analysis of variance. The results for the non-swirling cases could be analyzed as planned, and demonstrate that turbulence model selection, turbulence Schmidt number, and the type of injection …
Date: September 30, 2011
Creator: McDonell, Vincent; Hill, Scott; Akbari, Amin & McDonell, Vincent
Object Type: Report
System: The UNT Digital Library
High Extraction Phosphors for Solid State Lighting (open access)

High Extraction Phosphors for Solid State Lighting

We have developed high-index, high efficiency bulk luminescent materials and novel nano-sized phosphors for improved solid-state white LED lamps. These advances can potentially contribute to reducing the loss in luminous efficiencies due to scattering, re-absorption, and thermal quenching. The bulk and nanostructured luminescent materials investigated are index matched to GaN and have broad and size-tunable absorption bands, size and impurity tuned emission bands, size-driven elimination of scattering effects, and a separation between absorption and emission bands. These innovations were accomplished through the use of novel synthesis techniques suitable for high volume production for LED lamp applications. The program produced a full-color set of high quantum yield phosphors with high chemical stability. In the bulk phosphor study, the ZnSeS:Cu,Ag phosphor was optimized to achieve >91% efficiency using erbium (Er) and other activators as sensitizers. Detailed analysis of temperature quenching effects on a large number of ZnSeS:Cu,Ag,X and strontium- and calcium-thiogallate phosphors lead to a breakthrough in the understanding of the “anti-quenching” behavior and a physical bandgap model was developed of this phenomena. In a follow up to this study, optimized phosphor blends for high efficiency and color performance were developed and demonstrated a 2-component phosphor system with good white chromaticity, color …
Date: September 30, 2011
Creator: Summers, Chris; Menkara, Hisham & Wagner, Brent
Object Type: Report
System: The UNT Digital Library
Federal Market Information Technology in the Post Flash Crash Era: Roles for Supercomputing (open access)

Federal Market Information Technology in the Post Flash Crash Era: Roles for Supercomputing

This paper describes collaborative work between active traders, regulators, economists, and supercomputing researchers to replicate and extend investigations of the Flash Crash and other market anomalies in a National Laboratory HPC environment. Our work suggests that supercomputing tools and methods will be valuable to market regulators in achieving the goal of market safety, stability, and security. Research results using high frequency data and analytics are described, and directions for future development are discussed. Currently the key mechanism for preventing catastrophic market action are “circuit breakers.” We believe a more graduated approach, similar to the “yellow light” approach in motorsports to slow down traffic, might be a better way to achieve the same goal. To enable this objective, we study a number of indicators that could foresee hazards in market conditions and explore options to confirm such predictions. Our tests confirm that Volume Synchronized Probability of Informed Trading (VPIN) and a version of volume Herfindahl-Hirschman Index (HHI) for measuring market fragmentation can indeed give strong signals ahead of the Flash Crash event on May 6 2010. This is a preliminary step toward a full-fledged early-warning system for unusual market conditions.
Date: September 16, 2011
Creator: Bethel, E. Wes; Leinweber, David; Ruebel, Oliver & Wu, Kesheng
Object Type: Article
System: The UNT Digital Library
FY12 ARRA-NRAP Report – Studies to Support Risk Assessment of Geologic Carbon Sequestration (open access)

FY12 ARRA-NRAP Report – Studies to Support Risk Assessment of Geologic Carbon Sequestration

This report summarizes results of research conducted during FY2012 to support the assessment of environmental risks associated with geologic carbon dioxide (CO2) sequestration and storage. Several research focus areas are ongoing as part of this project. This includes the quantification of the leachability of metals and organic compounds from representative CO2 storage reservoir and caprock materials, the fate of metals and organic compounds after release, and the development of a method to measure pH in situ under supercritical CO2 (scCO2) conditions. Metal leachability experiments were completed on 6 different rock samples in brine in equilibrium with scCO2 at representative geologic reservoir conditions. In general, the leaching of RCRA metals and other metals of concern was found to be limited and not likely to be a significant issue (at least, for the rocks tested). Metals leaching experiments were also completed on 1 rock sample with scCO2 containing oxygen at concentrations of 0, 1, 5, and 10% to simulate injection of CO2 originating from the oxy-fuel combustion process. Significant differences in the leaching behavior of certain metals were observed when oxygen is present in the CO2. These differences resulted from oxidation of sulfides, release of sulfate, ferric iron and other metals, and …
Date: September 27, 2011
Creator: Cantrell, Kirk J.; Shao, Hongbo; Thompson, C. J.; Zhong, Lirong; Jung, Hun Bok & Um, Wooyong
Object Type: Report
System: The UNT Digital Library
Sensitivity of Fischer-Tropsch Synthesis and Water-Gas Shift Catalysts to Poisons from High-Temperature High-Pressure Entrained-Flow (EF) Oxygen-Blown Gasifier Gasification of Coal/Biomass Mixtures (open access)

Sensitivity of Fischer-Tropsch Synthesis and Water-Gas Shift Catalysts to Poisons from High-Temperature High-Pressure Entrained-Flow (EF) Oxygen-Blown Gasifier Gasification of Coal/Biomass Mixtures

There has been a recent shift in interest in converting not only natural gas and coal derived syngas to Fischer-Tropsch synthesis products, but also converting biomass-derived syngas, as well as syngas derived from coal and biomass mixtures. As such, conventional catalysts based on iron and cobalt may not be suitable without proper development. This is because, while ash, sulfur compounds, traces of metals, halide compounds, and nitrogen-containing chemicals will likely be lower in concentration in syngas derived from mixtures of coal and biomass (i.e., using entrained-flow oxygen-blown gasifier gasification gasification) than solely from coal, other compounds may actually be increased. Of particular concern are compounds containing alkali chemicals like the chlorides of sodium and potassium. In the first year, University of Kentucky Center for Applied Energy Research (UK-CAER) researchers completed a number of tasks aimed at evaluating the sensitivity of cobalt and iron-based Fischer-Tropsch synthesis (FT) catalysts and a commercial iron-chromia high temperature water-gas shift catalyst (WGS) to alkali halides. This included the preparation of large batches of 0.5%Pt-25%Co/Al{sub 2}O{sub 3} and 100Fe: 5.1Si: 3.0K: 2.0Cu (high alpha) catalysts that were split up among the four different entities participating in the overall project; the testing of the catalysts under clean …
Date: September 30, 2011
Creator: Davis, Burton; Jacobs, Gary; Ma, Wenping; Sparks, Dennis; Azzam, Khalid; Mohandas, Janet Chakkamadathil et al.
Object Type: Report
System: The UNT Digital Library
Renewable Energy Requirements for Future Building Codes: Options for Compliance (open access)

Renewable Energy Requirements for Future Building Codes: Options for Compliance

As the model energy codes are improved to reach efficiency levels 50 percent greater than current codes, use of on-site renewable energy generation is likely to become a code requirement. This requirement will be needed because traditional mechanisms for code improvement, including envelope, mechanical and lighting, have been pressed to the end of reasonable limits. Research has been conducted to determine the mechanism for implementing this requirement (Kaufman 2011). Kaufmann et al. determined that the most appropriate way to structure an on-site renewable requirement for commercial buildings is to define the requirement in terms of an installed power density per unit of roof area. This provides a mechanism that is suitable for the installation of photovoltaic (PV) systems on future buildings to offset electricity and reduce the total building energy load. Kaufmann et al. suggested that an appropriate maximum for the requirement in the commercial sector would be 4 W/ft{sup 2} of roof area or 0.5 W/ft{sup 2} of conditioned floor area. As with all code requirements, there must be an alternative compliance path for buildings that may not reasonably meet the renewables requirement. This might include conditions like shading (which makes rooftop PV arrays less effective), unusual architecture, undesirable …
Date: September 30, 2011
Creator: Dillon, Heather E.; Antonopoulos, Chrissi A.; Solana, Amy E. & Russo, Bryan J.
Object Type: Report
System: The UNT Digital Library
Reassessing Wind Potential Estimates for India: Economic and Policy Implications (open access)

Reassessing Wind Potential Estimates for India: Economic and Policy Implications

We assess developable on-shore wind potential in India at three different hub-heights and under two sensitivity scenarios – one with no farmland included, the other with all farmland included. Under the “no farmland included” case, the total wind potential in India ranges from 748 GW at 80m hub-height to 976 GW at 120m hub-height. Under the “all farmland included” case, the potential with a minimum capacity factor of 20 percent ranges from 984 GW to 1,549 GW. High quality wind energy sites, at 80m hub-height with a minimum capacity factor of 25 percent, have a potential between 253 GW (no farmland included) and 306 GW (all farmland included). Our estimates are more than 15 times the current official estimate of wind energy potential in India (estimated at 50m hub height) and are about one tenth of the official estimate of the wind energy potential in the US.
Date: September 15, 2011
Creator: Phadke, Amol; Bharvirkar, Ranjit & Khangura, Jagmeet
Object Type: Report
System: The UNT Digital Library
Product Characterization for Entrained Flow Coal/Biomass Co-Gasification (open access)

Product Characterization for Entrained Flow Coal/Biomass Co-Gasification

The U.S. Department of Energy‘s National Energy Technology Laboratory (DOE NETL) is exploring affordable technologies and processes to convert domestic coal and biomass resources to high-quality liquid hydrocarbon fuels. This interest is primarily motivated by the need to increase energy security and reduce greenhouse gas emissions in the United States. Gasification technologies represent clean, flexible and efficient conversion pathways to utilize coal and biomass resources. Substantial experience and knowledge had been developed worldwide on gasification of either coal or biomass. However, reliable data on effects of blending various biomass fuels with coal during gasification process and resulting syngas composition are lacking. In this project, GE Global Research performed a complete characterization of the gas, liquid and solid products that result from the co-gasification of coal/biomass mixtures. This work was performed using a bench-scale gasifier (BSG) and a pilot-scale entrained flow gasifier (EFG). This project focused on comprehensive characterization of the products from gasifying coal/biomass mixtures in a high-temperature, high-pressure entrained flow gasifier. Results from this project provide guidance on appropriate gas clean-up systems and optimization of operating parameters needed to develop and commercialize gasification technologies. GE‘s bench-scale test facility provided the bulk of high-fidelity quantitative data under temperature, heating rate, …
Date: September 30, 2011
Creator: Maghzi, Shawn; Subramanian, Ramanathan; Rizeq, George; Singh, Surinder; McDermott, John; Eiteneer, Boris et al.
Object Type: Report
System: The UNT Digital Library
The Value of Energy Performance and Green Attributes in Buildings: A Review of Existing Literature and Recommendations for Future Research (open access)

The Value of Energy Performance and Green Attributes in Buildings: A Review of Existing Literature and Recommendations for Future Research

Labels, certifications, and rating systems for energy efficiency performance and “green” attributes of buildings have been available in the U.S. for over 10 years, and used extensively in the European Union and Australia for longer. Such certifications and ratings can make energy efficiency more visible, and could help spur demand for energy efficiency if these designations are shown to have a positive impact on sales or rental prices. This policy brief discusses the findings and methodologies from recent studies on this topic, and suggests recommendations for future research. Although there have been just a handful of studies within the last 10 years that have investigated these effects, a few key findings emerge: To maximize sales price impact, label or rating information must be disclosed early and visibly in the sales process; The approach to evaluating energy efficiency labels (e.g., ENERGY STAR) and general “green” certifications (e.g., LEED or GreenPoint Rated) may need to be different, depending on the type, vintage and market penetration of the label; Collaborative efforts to promote label adoption and build a large dataset of labeled buildings will be required to produce reliable study results.
Date: September 7, 2011
Creator: Stuart, Elizabeth
Object Type: Report
System: The UNT Digital Library
Joint inversion of marine seismic AVA and CSEM data using statistical rock-physics models and Markov random fields: Stochastic inversion of AVA and CSEM data (open access)

Joint inversion of marine seismic AVA and CSEM data using statistical rock-physics models and Markov random fields: Stochastic inversion of AVA and CSEM data

Joint inversion of seismic AVA and CSEM data requires rock-physics relationships to link seismic attributes to electrical properties. Ideally, we can connect them through reservoir parameters (e.g., porosity and water saturation) by developing physical-based models, such as Gassmann’s equations and Archie’s law, using nearby borehole logs. This could be difficult in the exploration stage because information available is typically insufficient for choosing suitable rock-physics models and for subsequently obtaining reliable estimates of the associated parameters. The use of improper rock-physics models and the inaccuracy of the estimates of model parameters may cause misleading inversion results. Conversely, it is easy to derive statistical relationships among seismic and electrical attributes and reservoir parameters from distant borehole logs. In this study, we develop a Bayesian model to jointly invert seismic AVA and CSEM data for reservoir parameter estimation using statistical rock-physics models; the spatial dependence of geophysical and reservoir parameters are carried out by lithotypes through Markov random fields. We apply the developed model to a synthetic case, which simulates a CO{sub 2} monitoring application. We derive statistical rock-physics relations from borehole logs at one location and estimate seismic P- and S-wave velocity ratio, acoustic impedance, density, electrical resistivity, lithotypes, porosity, and water …
Date: September 15, 2011
Creator: Chen, J. & Hoversten, G.M.
Object Type: Article
System: The UNT Digital Library
Full Scale Field Trial of the Low Temperature Mercury Capture Process (open access)

Full Scale Field Trial of the Low Temperature Mercury Capture Process

CONSOL Energy Inc., with partial funding from the Department of Energy (DOE) National Energy Technology Laboratory, designed a full-scale installation for a field trial of the Low-Temperature Mercury Control (LTMC) process, which has the ability to reduce mercury emissions from coal-fired power plants by over 90 percent, by cooling flue gas temperatures to approximately 230 °F and absorbing the mercury on the native carbon in the fly ash, as was recently demonstrated by CONSOL R&D on a slip-stream pilot plant at the Allegheny Energy Mitchell Station with partial support by DOE. LTMC has the potential to remove over 90 percent of the flue gas mercury at a cost at least an order of magnitude lower (on a $/lb mercury removed basis) than activated carbon injection. The technology is suitable for retrofitting to existing and new plants, and, although it is best suited to bituminous coal-fired plants, it may have some applicability to the full range of coal types. Installation plans were altered and moved from the original project host site, PPL Martins Creek plant, to a second host site at Allegheny Energy’s R. Paul Smith plant, before installation actually occurred at the Jamestown (New York) Board of Public Utilities (BPU) …
Date: September 30, 2011
Creator: Locke, James & Winschel, Richard
Object Type: Report
System: The UNT Digital Library
Analysis of the Johns Hopkins Neutron Background Measurements (open access)

Analysis of the Johns Hopkins Neutron Background Measurements

This report addresses the analysis of the Johns Hopkins neutron background measurements.
Date: September 1, 2011
Creator: Hausladen, Paul & McConchie, Seth M
Object Type: Report
System: The UNT Digital Library
Characterizing Uncertainty for Regional Climate Change Mitigation and Adaptation Decisions (open access)

Characterizing Uncertainty for Regional Climate Change Mitigation and Adaptation Decisions

This white paper describes the results of new research to develop an uncertainty characterization process to help address the challenges of regional climate change mitigation and adaptation decisions.
Date: September 30, 2011
Creator: Unwin, Stephen D.; Moss, Richard H.; Rice, Jennie S. & Scott, Michael J.
Object Type: Report
System: The UNT Digital Library
Proceedings of the Inaugural Meeting of the International Forum for Reactor Aging Management (IFRAM) (open access)

Proceedings of the Inaugural Meeting of the International Forum for Reactor Aging Management (IFRAM)

In almost all countries with nuclear power plants (NPPs), regulatory authorities and the nuclear industry are looking at some form of extended operating periods. To support life extension activities it is necessary to ensure the continued safety and reliability of system, structures, and components, and the component materials. Internationally, a variety of individual national and international activities have been initiated including Plant Life Management through the International Atomic Energy Agency, Electric Power Research Institute’s Long Term Operation program, and various national programs in managing materials degradation and related topics. The U.S. Nuclear Regulatory Commission (NRC) engaged the international community in workshops in 2005-2006 to identify research needs and to collect information in an expert panel report on Proactive Management of Materials Degradation (PMMD), which was reported in NUREG/CR-6923. These results are also available via an Information Tool on the internet at http://pmmd.pnl.gov. This information builds on the extensive compilations known as the GALL Report (Generic Aging Lessons Learned, NUREG-1801, Vols. 1 and 2). Pacific Northwest National Laboratory (PNNL) recently issued a report on the review of various international activities in PMMD (PNNL-17779). There have also been initiatives by Electricite de France, Tokyo Electric Power Company, EPRI, and others to establish …
Date: September 1, 2011
Creator: Bond, Leonard J. & Brenchley, David L.
Object Type: Report
System: The UNT Digital Library
Recommendation for Mitigations of the Electron Cloud Instability in the ILC (open access)

Recommendation for Mitigations of the Electron Cloud Instability in the ILC

Electron cloud has been identified as one of the highest priority issues for the international Linear Collider (ILC) Damping Rings (DR). An electron cloud Working Group (WG) has evaluated the electron cloud effect and instability, and mitigation solutions for the electron cloud formation. Working group deliverables include recommendations for the baseline and alternate solutions to the electron cloud formation in various regions of the ILC Positron DR, which is presently assumed to be the 3.2 km design. Detailed studies of a range of mitigation options including coatings, clearing electrodes, grooves and novel concepts, were carried out over the previous several years by nearly 50 researchers, and the results of the studies form the basis for the recommendation. The recommendations are the result of the working group discussions held at numerous meetings and during a dedicated workshop. In addition, a number of items requiring further investigation were identified during the discussions at the Cornell meeting and studies will be carried out at CesrTA, a test accelerator dedicated to electron cloud studies, and other institutions.
Date: September 4, 2011
Creator: Pivi, M. T. F.; Wang, L.; Demma, T.; Guiducci, S.; Suetsugu, Y.; Shibata, K. et al.
Object Type: Article
System: The UNT Digital Library
Scientific Data Services -- A High-Performance I/O System with Array Semantics (open access)

Scientific Data Services -- A High-Performance I/O System with Array Semantics

As high-performance computing approaches exascale, the existing I/O system design is having trouble keeping pace in both performance and scalability. We propose to address this challenge by adopting database principles and techniques in parallel I/O systems. First, we propose to adopt an array data model because many scientific applications represent their data in arrays. This strategy follows a cardinal principle from database research, which separates the logical view from the physical layout of data. This high-level data model gives the underlying implementation more freedom to optimize the physical layout and to choose the most effective way of accessing the data. For example, knowing that a set of write operations is working on a single multi-dimensional array makes it possible to keep the subarrays in a log structure during the write operations and reassemble them later into another physical layout as resources permit. While maintaining the high-level view, the storage system could compress the user data to reduce the physical storage requirement, collocate data records that are frequently used together, or replicate data to increase availability and fault-tolerance. Additionally, the system could generate secondary data structures such as database indexes and summary statistics. We expect the proposed Scientific Data Services approach …
Date: September 21, 2011
Creator: Wu, Kesheng; Byna, Surendra; Rotem, Doron & Shoshani, Arie
Object Type: Article
System: The UNT Digital Library
Efficient scalable algorithms for hierarchically semiseparable matrices (open access)

Efficient scalable algorithms for hierarchically semiseparable matrices

Hierarchically semiseparable (HSS) matrix algorithms are emerging techniques in constructing the superfast direct solvers for both dense and sparse linear systems. Here, we develope a set of novel parallel algorithms for the key HSS operations that are used for solving large linear systems. These include the parallel rank-revealing QR factorization, the HSS constructions with hierarchical compression, the ULV HSS factorization, and the HSS solutions. The HSS tree based parallelism is fully exploited at the coarse level. The BLACS and ScaLAPACK libraries are used to facilitate the parallel dense kernel operations at the #12;ne-grained level. We have appplied our new parallel HSS-embedded multifrontal solver to the anisotropic Helmholtz equations for seismic imaging, and were able to solve a linear system with 6.4 billion unknowns using 4096 processors, in about 20 minutes. The classical multifrontal solver simply failed due to high demand of memory. To our knowledge, this is the #12;first successful demonstration of employing the HSS algorithms in solving the truly large-scale real-world problems. Our parallel strategies can be easily adapted to the parallelization of the other rank structured methods.
Date: September 14, 2011
Creator: Wang, Shen; Xia, Jianlin; Situ, Yingchong & Hoop, Maarten V. de
Object Type: Article
System: The UNT Digital Library
CO{sub 2} Capture Membrane Process for Power Plant Flue Gas (open access)

CO{sub 2} Capture Membrane Process for Power Plant Flue Gas

Because the fleet of coal-fired power plants is of such importance to the nation’s energy production while also being the single largest emitter of CO{sub 2}, the development of retrofit, post-combustion CO{sub 2} capture technologies for existing and new, upcoming coal power plants will allow coal to remain a major component of the U.S. energy mix while mitigating global warming. Post-combustion carbon capture technologies are an attractive option for coal-fired power plants as they do not require modification of major power-plant infrastructures, such as fuel processing, boiler, and steam-turbine subsystems. In this project, the overall objective was to develop an advanced, hollow-fiber, polymeric membrane process that could be cost-effectively retrofitted into current pulverized coal-fired power plants to capture at least 90% of the CO{sub 2} from plant flue gas with 95% captured CO{sub 2} purity. The approach for this project tackled the technology development on three different fronts in parallel: membrane materials R&D, hollow-fiber membrane module development, and process development and engineering. The project team consisted of RTI (prime) and two industrial partners, Arkema, Inc. and Generon IGS, Inc. Two CO{sub 2}-selective membrane polymer platforms were targeted for development in this project. For the near term, a next-generation, high-flux polycarbonate …
Date: September 30, 2011
Creator: Toy, Lora; Kataria, Atish & Gupta, Raghubir
Object Type: Report
System: The UNT Digital Library
A Nanocrystal Sensor for Luminescence Detection of Cellular Forces (open access)

A Nanocrystal Sensor for Luminescence Detection of Cellular Forces

Quantum dots have been used as bright fluorescent tags with high photostability to probe numerous biological systems. In this work we present the tetrapod quantum dot as a dynamic, next-generation nanocrystal probe that fluorescently reports cellular forces with spatial and temporal resolution. Its small size and colloidal state suggest that the tetrapod may be further developed as a tool to measure cellular forces in vivo and with macromolecular spatial resolution.
Date: September 29, 2011
Creator: Choi, Charina; Chou, Jonathan; Lutker, Katie; Werb, Zena & Alivisatos, Paul
Object Type: Article
System: The UNT Digital Library