FY 2005 Congressional Earmark: The Environmental Institute Fellowship Program (open access)

FY 2005 Congressional Earmark: The Environmental Institute Fellowship Program

Congressional Earmark Funding was used to create a Postdoctoral Environmental Fellowship Program, interdisciplinary Environmental Working Groups, and special initiatives to create a dialogue around the environment at the University of Massachusetts Amherst to mobilize faculty to work together to respond to emerging environmental needs and to build institutional capacity to launch programmatic environmental activities across campus over time. Developing these networks of expertise will enable the University to more effectively and swiftly respond to emerging environmental needs and assume a leadership role in varied environmental fields. Over the course of the project 20 proposals were submitted to a variety of funding agencies involving faculty teams from 19 academic departments; 4 projects were awarded totaling $950,000; special events were organized including the Environmental Lecture Series which attracted more than 1,000 attendees over the course of the project; 75 University faculty became involved in one or more Working Groups (original three Working Groups plus Phase 2 Working Groups); an expertise database was developed with approximately 275 faculty involved in environmental research and education as part of a campus-wide network of environmental expertise; 12 University centers and partners participated; and the three Environmental Fellows produced 3 publications as well as a number of …
Date: February 6, 2007
Creator: Tracey, Sharon & Taupier, Richard
Object Type: Text
System: The UNT Digital Library
Geometric Effects on Electron Cloud (open access)

Geometric Effects on Electron Cloud

The development of an electron cloud in the vacuum chambers of high intensity positron and proton storage rings may limit the machine performances by inducing beam instabilities, beam emittance increase, beam loss, vacuum pressure increases and increased heat load on the vacuum chamber wall. The electron multipacting is a kind of geometric resonance phenomenon and thus is sensitive to the geometric parameters such as the aperture of the beam pipe, beam shape and beam bunch fill pattern, etc. This paper discusses the geometric effects on the electron cloud build-up in a beam chamber and examples are given for different beams and accelerators.
Date: July 6, 2007
Creator: Wang, L.
Object Type: Article
System: The UNT Digital Library
Geometric metastability, quivers and holography (open access)

Geometric metastability, quivers and holography

We use large N duality to study brane/anti-brane configurations on a class of Calabi-Yau manifolds. With only branes present, the Calabi-Yau manifolds in question give rise to N=2 ADE quiver theories deformed by superpotential terms. We show that the large N duality conjecture of hep-th/0610249 reproduces correctly the known qualitative features of the brane/anti-brane physics. In the supersymmetric case, the gauge theories have Seiberg dualities which are represented as flops in the geometry. Moreover, the holographic dual geometry encodes the whole RG flow of the gauge theory. In the non-supersymmetric case, the large N duality predicts that the brane/anti-brane theories also enjoy such dualities, and allows one to pick out the good description at a given energy scale.
Date: September 6, 2007
Creator: Aganagic, Mina; Aganagic, Mina; Beem, Christopher & Freivogel, Ben
Object Type: Article
System: The UNT Digital Library
GLASS SELECTION STRATEGY: DEVELOPMENT OF US AND KRI TEST MATRICIES (open access)

GLASS SELECTION STRATEGY: DEVELOPMENT OF US AND KRI TEST MATRICIES

High-level radioactive wastes are stored as liquids in underground storage tanks at the Department of Energy's (DOE) Savannah River Site (SRS) and Hanford Reservation. These wastes are to be prepared for permanent disposition in a geologic repository by vitrification with glass forming additives (e.g., frit), creating a waste form with long-term durability. Wastes at SRS are being vitrified in the Defense Waste Processing Facility (DWPF). Vitrification of the wastes stored at Hanford is planned for the Waste Treatment and Immobilization Plant (WTP) when completed. Some of the wastes at SRS, and particularly those at Hanford, contain high concentrations of aluminum, chromium and sulfate. These elements make it more difficult to produce a waste glass with a high waste loading (WL) without crystallization occurring in the glass (either within the melter or upon cooling of the glass), potentially exceeding the solubility limit of critical components, having negative impacts on durability, and/or resulting in the formation of a sulfate salt layer on the molten glass surface. Although the overall scope of the task is focused on all three critical, chemical components, the current work will primarily address the potential for crystallization (e.g., nepheline and/or spinel) in high level waste (HLW) glasses. Recent …
Date: February 6, 2007
Creator: Fox, K; Tommy Edwards, T & David Peeler, D
Object Type: Report
System: The UNT Digital Library
GoMRC Website ‘Meta-analysis Report: Land-use and submerged aquatic vegetation change in the Gulf of Mexico’ (open access)

GoMRC Website ‘Meta-analysis Report: Land-use and submerged aquatic vegetation change in the Gulf of Mexico’

Over the past century, health and spatial extent of seagrasses has decreased dramatically in the Gulf of Mexico. While some of the changes can be explained by direct impacts to the seagrass beds, we hypothesize that changes in the land use in the watersheds can also be correlated with the decline of seagrasses. Through this meta-analysis, we researched historical and compared trends in seagrass populations and land use in five bays and their watersheds within the Gulf of Mexico: Mobile Bay, Perdido Bay, Tampa Bay, Charlotte Harbor, and Galveston Bay. Using both historical records and spatial datasets, we examined land use and seagrass trends in these five areas.
Date: December 6, 2007
Creator: Judd, Chaeli; Stefansson, Emily S. & Brushnahan, Heather
Object Type: Report
System: The UNT Digital Library
Hafnium Resonance Parameter Analysis Using Neutron Capture and Transmission Experiments (open access)

Hafnium Resonance Parameter Analysis Using Neutron Capture and Transmission Experiments

The focus of this work is to determine the resonance parameters for stable hafnium isotopes in the 0.005 - 200 eV region, with special emphasis on the overlapping {sup 176}Hf and {sup 178}Hf resonances near 8 eV. Accurate hafnium cross sections and resonance parameters are needed in order to quantify the effects of hafnium found in zirconium, a metal commonly used in reactors. The accuracy of the cross sections and the corresponding resonance parameters used in current nuclear analysis tools are rapidly becoming the limiting factor in reducing the overall uncertainty on reactor physics calculations. Experiments measuring neutron capture and transmission are routinely performed at the Rensselaer Polytechnic Institute (RPI) LINAC using the time-of flight technique. {sup 6}Li glass scintillation detectors were used for transmission experiments at flight path lengths of 15 and 25 m, respectively. Capture experiments were performed using a sixteen section NaI multiplicity detector at a flight path length of 25 m. These experiments utilized several thicknesses of metallic and isotope-enriched liquid Hf samples. The liquid Hf samples were designed to provide information on the {sup 176}Hf and {sup 178}Hf contributions to the 8 eV doublet without saturation. Data analyses were performed using the R-matrix Bayesian code …
Date: February 6, 2007
Creator: Trbovich, M J; Barry, D P; Slovacek, R E; Danon, Y; Block, R C; Francis, N C et al.
Object Type: Report
System: The UNT Digital Library
High Efficiency, Low Cost Scintillators for PET (open access)

High Efficiency, Low Cost Scintillators for PET

Inorganic scintillation detectors coupled to PMTs are an important element of medical imaging applications such as positron emission tomography (PET). Performance as well as cost of these systems is limited by the properties of the scintillation detectors available at present. The Phase I project was aimed at demonstrating the feasibility of producing high performance scintillators using a low cost fabrication approach. Samples of these scintillators were produced and their performance was evaluated. Overall, the Phase I effort was very successful. The Phase II project will be aimed at advancing the new scintillation technology for PET. Large samples of the new scintillators will be produced and their performance will be evaluated. PET modules based on the new scintillators will also be built and characterized.
Date: March 6, 2007
Creator: Shah, Kanai
Object Type: Report
System: The UNT Digital Library
High Electron Mobility InN (open access)

High Electron Mobility InN

None
Date: February 6, 2007
Creator: Jones, R. E.; Li, S. X.; Haller, E. E.; van Genuchten, H. C. M.; Yu, K. M.; Ager, J. W., III et al.
Object Type: Article
System: The UNT Digital Library
High Energy Neutrino Signals from the Epoch of Reionization (open access)

High Energy Neutrino Signals from the Epoch of Reionization

In this paper we perform a new estimate of the high energy neutrinos expected from GRBs associated with the first generation of stars in light of new models and constraints on the epoch of reionization and a more detailed evaluation of the neutrino emission yields. We also compare the diffuse high energy neutrino background from Population III stars with the one from ''ordinary stars'' (Population II), as estimated consistently within the same cosmological and astrophysical assumptions. In disagreement with previous literature, we find that high energy neutrinos from Population III stars will not be observable with current or near future neutrino telescopes, falling below both IceCube sensitivity and atmospheric neutrino background under the most extreme assumptions for the GRB rate. This rules them out as a viable diagnostic tool for these still elusive metal-free stars.
Date: July 6, 2007
Creator: Iocco, F.; Murase, K.; Nagataki, S. & Serpico, P.D.
Object Type: Report
System: The UNT Digital Library
High-Energy Neutron Imaging at LLNL (open access)

High-Energy Neutron Imaging at LLNL

LLNL is currently engaged in the development of high-energy (10 MeV) neutron imaging technology to complement existing x-ray diagnostic tools in U.S. Department of Energy (DOE) nondestructive evaluation (NDE) applications. Our goal is to develop and deploy a nonintrusive imaging system capable of detecting cubic-mm-scale voids, cracks or other significant structural defects in heavily-shielded low-Z materials within very thick objects. The final production-line system that we envision will be relatively compact (suitable for use in existing facilities within the DOE complex) and capable of acquiring both radiographic and tomographic (CT) images. In this paper, the design status of the high-intensity, accelerator-driven neutron source and large-format imaging detector associated with the system will be discussed and results from one recent neutron imaging experiment conducted at the Ohio University Accelerator Laboratory (OUAL) in Athens, OH will be presented.
Date: May 6, 2007
Creator: Hall, J; Rusnak, B & Fitsos, P
Object Type: Article
System: The UNT Digital Library
High Power FELs (open access)

High Power FELs

None
Date: September 6, 2007
Creator: Neil, George
Object Type: Article
System: The UNT Digital Library
A High Resolution Hydrometer Phase Classifier Based on Analysis of Cloud Radar Doppler Spectra. (open access)

A High Resolution Hydrometer Phase Classifier Based on Analysis of Cloud Radar Doppler Spectra.

The lifecycle and radiative properties of clouds are highly sensitive to the phase of their hydrometeors (i.e., liquid or ice). Knowledge of cloud phase is essential for specifying the optical properties of clouds, or else, large errors can be introduced in the calculation of the cloud radiative fluxes. Current parameterizations of cloud water partition in liquid and ice based on temperature are characterized by large uncertainty (Curry et al., 1996; Hobbs and Rangno, 1998; Intriery et al., 2002). This is particularly important in high geographical latitudes and temperature ranges where both liquid droplets and ice crystal phases can exist (mixed-phase cloud). The mixture of phases has a large effect on cloud radiative properties, and the parameterization of mixed-phase clouds has a large impact on climate simulations (e.g., Gregory and Morris, 1996). Furthermore, the presence of both ice and liquid affects the macroscopic properties of clouds, including their propensity to precipitate. Despite their importance, mixed-phase clouds are severely understudied compared to the arguably simpler single-phase clouds. In-situ measurements in mixed-phase clouds are hindered due to aircraft icing, difficulties distinguishing hydrometeor phase, and discrepancies in methods for deriving physical quantities (Wendisch et al. 1996, Lawson et al. 2001). Satellite-based retrievals of cloud …
Date: August 6, 2007
Creator: Luke,E. & Kollias, P.
Object Type: Article
System: The UNT Digital Library
Hot-Spot Avoidance With Multi-Pathing Over Infiniband: An MPI Perspective (open access)

Hot-Spot Avoidance With Multi-Pathing Over Infiniband: An MPI Perspective

Large scale InfiniBand clusters are becoming increasingly popular, as reflected by the TOP 500 Supercomputer rankings. At the same time, fat tree has become a popular interconnection topology for these clusters, since it allows multiple paths to be available in between a pair of nodes. However, even with fat tree, hot-spots may occur in the network depending upon the route configuration between end nodes and communication pattern(s) in the application. To make matters worse, the deterministic routing nature of InfiniBand limits the application from effective use of multiple paths transparently and avoid the hot-spots in the network. Simulation based studies for switches and adapters to implement congestion control have been proposed in the literature. However, these studies have focused on providing congestion control for the communication path, and not on utilizing multiple paths in the network for hot-spot avoidance. In this paper, we design an MPI functionality, which provides hot-spot avoidance for different communications, without a priori knowledge of the pattern. We leverage LMC (LID Mask Count) mechanism of InfiniBand to create multiple paths in the network and present the design issues (scheduling policies, selecting number of paths, scalability aspects) of our design. We implement our design and evaluate it …
Date: March 6, 2007
Creator: Vishnu, A; Koop, M; Moody, A; Mamidala, A R; Narravula, S & Panda, D K
Object Type: Article
System: The UNT Digital Library
Idaho CERCLA Disposal Facility Complex Compliance Demonstration for DOE Order 435.1 (open access)

Idaho CERCLA Disposal Facility Complex Compliance Demonstration for DOE Order 435.1

This compliance demonstration document provides an analysis of the Idaho CERCLA Disposal Facility (ICDF) Complex compliance with DOE Order 435.1. The ICDF Complex includes the disposal facility (landfill), evaporation pond, administration facility, weigh scale, and various staging/storage areas. These facilities were designed and constructed to be compliant with DOE Order 435.1, Resource Conservation and Recovery act Subtitle C, and Toxic Substances Control Act polychlorinated biphenyl design and construction standards. The ICDF Complex is designated as the Idaho National Laboratory (INL) facility for the receipt, staging/storage, treatment, and disposal of INL Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) waste streams.
Date: November 6, 2007
Creator: Simonds, J.
Object Type: Report
System: The UNT Digital Library
Idaho CERCLA Disposal Facility Complex Compliance Demonstration for DOE Order 435.1 (open access)

Idaho CERCLA Disposal Facility Complex Compliance Demonstration for DOE Order 435.1

This compliance demonstration document provides an analysis of the Idaho CERCLA Disposal Facility (ICDF) Complex compliance with DOE Order 435.1. The ICDF Complex includes the disposal facility (landfill), evaporation pond, administration facility, weigh scale, and various staging/storage areas. These facilities were designed and constructed to be compliant with DOE Order 435.1, Resource Conservation and Recovery act Subtitle C, and Toxic Substances Control Act polychlorinated biphenyl design and construction standards. The ICDF Complex is designated as the Idaho National Laboratory (INL) facility for the receipt, staging/storage, treatment, and disposal of INL Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) waste streams.
Date: November 6, 2007
Creator: Simonds, J.
Object Type: Report
System: The UNT Digital Library
Identifying Isotropic Events Using an Improved Regional Moment Tensor Inversion Technique (open access)

Identifying Isotropic Events Using an Improved Regional Moment Tensor Inversion Technique

Using a regional time-domain waveform inversion for the complete moment tensor we calculate the deviatoric and isotropic source components for several explosions at the Nevada Test Site as well as earthquakes, and collapses in the surrounding region of the western US. The events separate into specific populations according to their deviation from a pure double-couple and ratio of isotropic to deviatoric energy. The separation allows for anomalous event identification and discrimination between explosions, earthquakes, and collapses. Error in the moment tensor solutions and source parameters is also calculated. We investigate the sensitivity of the moment tensor solutions to Green's functions calculated with imperfect Earth models, inaccurate event locations, and data with a low signal-to-noise ratio. We also test the performance of the method under a range of recording conditions from excellent azimuthal coverage to cases of sparse station availability, as might be expected for smaller events. Finally, we assess the depth and frequency dependence upon event size. This analysis will be used to determine the range where well-constrained solutions can be obtained.
Date: July 6, 2007
Creator: Ford, S R; Dreger, D S & Walter, W R
Object Type: Article
System: The UNT Digital Library
IEC International Standards Under Development For Radiation-Generating Devices (open access)

IEC International Standards Under Development For Radiation-Generating Devices

The International Electrotechnical Commission (IEC) is the leading and oldest global organization with over 100 years history of developing and publishing international standards for all electrical, electronic and related technologies, including radiation detection instrumentation. Subcommittee 45B 'Radiation Protection Instrumentation' of the IEC has recently started the development of two standards on radiation-generating devices. IEC 62463 'Radiation protection instrumentation--X-ray Systems for the Screening of Persons for Security and the Carrying of Illicit Items' is applicable to X-ray systems designed for screening people to detect if they are carrying objects such as weapons, explosives, chemical and biological agents and other concealed items that could be used for criminal purposes, e.g. terrorist use, drug smuggling, etc. IEC 62523 'Radiation protection instrumentation--Cargo/Vehicle radiographic inspection systems' applies to cargo/vehicle imaging inspection systems using accelerator produced X-ray or gamma radiation to obtain images of the screened objects (e.g. cargo containers, transport and passenger vehicles and railroad cars). The objective of both standards is to specify standard requirements and general characteristics and test procedures, as well as, radiation, electrical, environmental, mechanical, and safety requirements and to provide examples of acceptable methods to test these requirements. In particular the standards address the design requirements as they relate to …
Date: December 6, 2007
Creator: Voytchev, M; Radev, R; Chiaro, P; Thomson, I; Dray, C & Li, J
Object Type: Article
System: The UNT Digital Library
Image Ellipticity from Atmospheric Aberrations (open access)

Image Ellipticity from Atmospheric Aberrations

We investigate the ellipticity of the point-spread function (PSF) produced by imaging an unresolved source with a telescope, subject to the effects of atmospheric turbulence. It is important to quantify these effects in order to understand the errors in shape measurements of astronomical objects, such as those used to study weak gravitational lensing of field galaxies. The PSF modeling involves either a Fourier transform of the phase information in the pupil plane or a ray-tracing approach, which has the advantage of requiring fewer computations than the Fourier transform. Using a standard method, involving the Gaussian weighted second moments of intensity, we then calculate the ellipticity of the PSF patterns. We find significant ellipticity for the instantaneous patterns (up to more than 10%). Longer exposures, which we approximate by combining multiple (N) images from uncorrelated atmospheric realizations, yield progressively lower ellipticity (as 1/{radical}N). We also verify that the measured ellipticity does not depend on the sampling interval in the pupil plane using the Fourier method. However, we find that the results using the ray-tracing technique do depend on the pupil sampling interval, representing a gradual breakdown of the geometric approximation at high spatial frequencies. Therefore, ray tracing is generally not an …
Date: March 6, 2007
Creator: de Vries, W. H.; Olivier, S. S.; Asztalos, S. J.; Rosenberg, L. J. & Baker, K. L.
Object Type: Article
System: The UNT Digital Library
Impedance Calculations of Non-Axisymmetric Transitions Using the Optical Approximation (open access)

Impedance Calculations of Non-Axisymmetric Transitions Using the Optical Approximation

In a companion report, we have derived a method for finding the impedance at high frequencies of vacuum chamber transitions that are short compared to the catch-up distance, in a frequency regime that--in analogy to geometric optics for light--we call the optical regime. In this report we apply the method to various non-axisymmetric geometries such as irises/short collimators in a beam pipe, step-in transitions, step-out transitions, and more complicated transitions of practical importance. Most of our results are analytical, with a few given in terms of a simple one dimensional integral. Our results are compared to wakefield simulations with the time-domain, finite-difference program ECHO, and excellent agreement is found.
Date: March 6, 2007
Creator: Bane, K. L. F.; Stupakov, G. & Zagorodov, I.
Object Type: Article
System: The UNT Digital Library
Improved Convergence for Two-Component Activity Expansions (open access)

Improved Convergence for Two-Component Activity Expansions

It is well known that an activity expansion of the grand canonical partition function works well for attractive interactions, but works poorly for repulsive interactions, such as occur between atoms and molecules. The virial expansion of the canonical partition function shows just the opposite behavior. This poses a problem for applications that involve both types of interactions, such as occur in the outer layers of low-mass stars. We show that it is possible to obtain expansions for repulsive systems that convert the poorly performing Mayer activity expansion into a series of rational polynomials that converge uniformly to the virial expansion. In the current work we limit our discussion to the second virial approximation. In contrast to the Mayer activity expansion the activity expansion presented herein converges for both attractive and repulsive systems.
Date: March 6, 2007
Creator: DeWitt, H E; Rogers, F J & Sonnad, V
Object Type: Article
System: The UNT Digital Library
IMPROVING THERMAL PERFORMANCE OF RADIOACTIVE MATERIAL DRUM TYPEPACKAGES BY USING HEAT PIPES (open access)

IMPROVING THERMAL PERFORMANCE OF RADIOACTIVE MATERIAL DRUM TYPEPACKAGES BY USING HEAT PIPES

This paper presents a feasibility study to improve thermal loading of existing radioactive material packages by using heat pipes. The concept could be used to channel heat in certain directions and dissipate to the environment. The concept is applied to a drum type package because the drum type packages are stored and transported in an upright position. This orientation is suitable for heat pipe operation that could facilitate the heat pipe implementation in the existing well proven package designs or in new designs where thermal loading is high. In this position, heat pipes utilize gravity very effectively to enhance heat flow in the upward direction Heat pipes have extremely high effective thermal conductivity that is several magnitudes higher than the most heat conducting metals. In addition, heat pipes are highly unidirectional so that the effective conductivity for heat transfer in the reverse direction is greatly reduced. The concept is applied to the 9977 package that is currently going through the DOE certification review. The paper presents computer simulations using typical off-the-shelf heat pipe available configurations and performance data for the 9977 package. A path forward is outlined for implementing the concepts for further study and prototype testing.
Date: March 6, 2007
Creator: Gupta, N
Object Type: Article
System: The UNT Digital Library
Indiana Humanities Council Request for the Indianapolis Energy Conversion Inst. For Phase I of the Indianapolis Energy Conservation Res Initiative also called the smartDESKTOP Initiative (open access)

Indiana Humanities Council Request for the Indianapolis Energy Conversion Inst. For Phase I of the Indianapolis Energy Conservation Res Initiative also called the smartDESKTOP Initiative

The smartDESKTOP Initiative at the Indiana Humanities Council received critical support in building and delivering a “digital desktop” for Indiana educators through the Department of Energy Grant—DE-FG02-06ER64282. During the project period September 2006 through October of 2007, the number of Indiana educators with accounts on the smartDESKTOP more than tripled from under 2,000 to more than 7,000 accounts. An external review of the project conducted for the purposes of understanding the impact of the service in Indiana schools revealed that the majority of respondents felt that using the smartDESKTOP did reduce the time they spent managing paper. The same study revealed the challenges of implementing a digital desktop meant to help teachers leverage technology to improve their teaching and ultimately student learning. The most significant outcome of this project is that the Indiana Department of Education expressed interest in assuming responsibility for sustaining this project. The transition of the smartDESKTOP to the Indiana Department of Education was effective on November 1, 2007.
Date: December 6, 2007
Creator: Keller, John B.
Object Type: Report
System: The UNT Digital Library
Industrial Environmental Testing of Coupons and Prototype Cylinders Coated With Iron-Based Amorphous Alloys (open access)

Industrial Environmental Testing of Coupons and Prototype Cylinders Coated With Iron-Based Amorphous Alloys

Iron-based amorphous alloys are desirable for many industrial applications due to their dual capacity to resist corrosion and wear. These alloys may also contain a significant amount of boron which makes them candidates for criticality control, for example, in high-level nuclear waste disposition applications. The Fe-based amorphous alloys can be produced in powder form and then deposited using a HVOF thermal spray process on any surface that needs to be protected. For the current testing coupons of 316L stainless steels were coated with the amorphous alloy SAM2X5 and then tested for corrosion resistance in the salt-fog chamber and in other industrial environments. Prototype cylinders were also prepared and environmentally tested. One cylinder was 30-inch diameter, 88-inch long, and 3/8-inch thick. The coating thickness was 0.015 to 0.019-inch thick. The cylinder was in good condition after the test. Along the body of the cylinder only two pinpoint spot sized signs of rust were seen. Test results will be compared with the behavior of witness materials under the same tested conditions.
Date: March 6, 2007
Creator: Rebak, R B; Aprigliano, L F; Day, S D; Lian, T & Farmer, J C
Object Type: Article
System: The UNT Digital Library
Investigations of charged interfaces for electric vehicle applications (open access)

Investigations of charged interfaces for electric vehicle applications

We refined the parametrization of our model for the hydrogen evolution on Pt(111) in the presence of SO4H2 [1,2,3,4]. In particular we studied the effects of changing the turning point of the water. The form of the voltammogram is not very sensitive to the exact position of the turning point, which in previous work was treated as an adjustable parameter. Physically a reasonable choice is that the turning point is the PZC (point of zero charge). This new parametrization clarified some issues related to the mechanism of hydrogen oxidation. In the early stages of this project, we tried with N. Marzari [5] to compute the ex-situ structure of the bisulfate-water √3X√7 (or also 5/2X√7) phase, seen by STM. However, we were unsuccessful in reproducing the known structures of the phase, even though we used state of the art pseudo potentials. There are various possible reasons why this happens, but the most obvious one is the environment of the electrode surface. This means that we need a theory that is able to include the local microfield as a function of the applied potential and electrochemical environment, and hence, we need to fully develop the density functional of a real molecular solvent …
Date: March 6, 2007
Creator: Blum, Lesser
Object Type: Report
System: The UNT Digital Library