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ACRF Instrumentation Status: New, Current, and Future - September 2008 (open access)

ACRF Instrumentation Status: New, Current, and Future - September 2008

The purpose of this report is to provide a concise but comprehensive overview of Atmospheric Radiation Measurement Climate Research Facility instrumentation status. The report is divided into the following five sections: (1) new instrumentation in the process of being acquired and deployed, (2) field campaigns, (3) existing instrumentation and progress on improvements or upgrades, (4) proposed future instrumentation, and (5) Small Business Innovation Research instrument development.
Date: October 15, 2008
Creator: Voyles, J. W.
Object Type: Report
System: The UNT Digital Library
Analysis of Non-Enzymatically Glycated Peptides: Neutral-Loss Triggered MS3 Versus Multi-Stage Activation Tandem Mass Spectrometry (open access)

Analysis of Non-Enzymatically Glycated Peptides: Neutral-Loss Triggered MS3 Versus Multi-Stage Activation Tandem Mass Spectrometry

Non-enzymatic glycation of tissue proteins has important implications in the development of complications of diabetes mellitus. While electron transfer dissociation (ETD) has been shown to outperform collision-induced dissociation (CID) in sequencing glycated peptides by tandem mass spectrometry, ETD instrumentation is not yet available in all laboratories. In this study, we evaluated different advanced CID techniques (i.e., neutral-loss triggered MS3 and multi-stage activation) during LC-MSn analyses of Amadori-modified peptides enriched from human serum glycated in vitro. During neutral-loss triggered MS3 experiments, MS3 scans triggered by neutral-losses of 3 H2O or 3 H2O + HCHO produced similar results in terms of glycated peptide identifications. However, neutral losses of 3 H2O resulted in significantly more glycated peptide identifications during multi-stage activation experiments. Overall, the multi-stage activation approach produced more glycated peptide identifications, while the neutral-loss triggered MS3 approach resulted in much higher specificity. Both techniques offer a viable alternative to ETD for identifying glycated peptides when that method is unavailable.
Date: October 15, 2008
Creator: Zhang, Qibin; Petyuk, Vladislav A.; Schepmoes, Athena A.; Orton, Daniel J.; Monroe, Matthew E.; Yang, Feng et al.
Object Type: Article
System: The UNT Digital Library
Modeling of Carbon Migration During JET Injection Experiments (open access)

Modeling of Carbon Migration During JET Injection Experiments

JET has performed two dedicated carbon migration experiments on the final run day of separate campaigns (2001 and 2004) using {sup 13}CH{sub 4} methane injected into repeated discharges. The EDGE2D/NIMBUS code modelled the carbon migration in both experiments. This paper describes this modelling and identifies a number of important migration pathways: (1) deposition and erosion near the injection location, (2) migration through the main chamber SOL, (3) migration through the private flux region aided by E x B drifts, and (4) neutral migration originating near the strike points. In H-Mode, type I ELMs are calculated to influence the migration by enhancing erosion during the ELM peak and increasing the long-range migration immediately following the ELM. The erosion/re-deposition cycle along the outer target leads to a multistep migration of {sup 13}C towards the separatrix which is called 'walking'. This walking created carbon neutrals at the outer strike point and led to {sup 13}C deposition in the private flux region. Although several migration pathways have been identified, quantitative analyses are hindered by experimental uncertainty in divertor leakage, and the lack of measurements at locations such as gaps and shadowed regions.
Date: October 15, 2008
Creator: Strachan, J. D.; Likonen, J.; Coad, P.; Rubel, M.; Widdowson, A.; Airila, M. et al.
Object Type: Report
System: The UNT Digital Library
Extension of the operating parameters of the two stage light gas gun to velocities below 2 km/sec. (open access)

Extension of the operating parameters of the two stage light gas gun to velocities below 2 km/sec.

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Date: October 15, 2007
Creator: Thoe, R S
Object Type: Article
System: The UNT Digital Library
Development and Integration of Hardware and Software for Active-Sensors in Structural Monitoring (open access)

Development and Integration of Hardware and Software for Active-Sensors in Structural Monitoring

Structural Health Monitoring (SHM) promises to deliver great benefits to many industries. Primarily among them is a potential for large cost savings in maintenance of complex structures such as aircraft and civil infrastructure. However, several large obstacles remain before widespread use on structures can be accomplished. The development of three components would address many of these obstacles: a robust sensor validation procedure, a low-cost active-sensing hardware and an integrated software package for transition to field deployment. The research performed in this thesis directly addresses these three needs and facilitates the adoption of SHM on a larger scale, particularly in the realm of SHM based on piezoelectric (PZT) materials. The first obstacle addressed in this thesis is the validation of the SHM sensor network. PZT materials are used for sensor/actuators because of their unique properties, but their functionality also needs to be validated for meaningful measurements to be recorded. To allow for a robust sensor validation algorithm, the effect of temperature change on sensor diagnostics and the effect of sensor failure on SHM measurements were classified. This classification allowed for the development of a sensor diagnostic algorithm that is temperature invariant and can indicate the amount and type of sensor failure. …
Date: October 15, 2007
Creator: Overly, Timothy G.S.
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Detection of low energy single ion impacts in micron scaletransistors at room temperature (open access)

Detection of low energy single ion impacts in micron scaletransistors at room temperature

We report the detection of single ion impacts throughmonitoring of changes in the source-drain currents of field effecttransistors (FET) at room temperature. Implant apertures are formed inthe interlayer dielectrics and gate electrodes of planar, micro-scaleFETs by electron beam assisted etching. FET currents increase due to thegeneration of positively charged defects in gate oxides when ions(121Sb12+, 14+, Xe6+; 50 to 70 keV) impinge into channel regions. Implantdamage is repaired by rapid thermal annealing, enabling iterative cyclesof device doping and electrical characterization for development ofsingle atom devices and studies of dopant fluctuationeffects.
Date: October 15, 2007
Creator: Batra, A.; Weis, C. D.; Reijonen, J.; Persaud, A.; Schenkel, T.; Cabrini, S. et al.
Object Type: Article
System: The UNT Digital Library
John Pendry: His Contributions to the Development of LEED Surface Crystallography (open access)

John Pendry: His Contributions to the Development of LEED Surface Crystallography

In this paper we discuss the pivotal role played by Sir John Pendry in the development of Low Energy Electron Diffraction (LEED) during the past three decades; the earliest understanding on the physics of LEED to the development of sophisticated methods for the structural solution of complex surfaces.
Date: October 15, 2007
Creator: Somorjai, Gabor A. & Rous, P. J.
Object Type: Article
System: The UNT Digital Library
The National Ignition Facility: The world's largest optical system (open access)

The National Ignition Facility: The world's largest optical system

The National Ignition Facility (NIF), a 192-beam fusion laser, is presently under construction at the Lawrence Livermore National Laboratory with an expected completion in 2008. The facility contains 7,456 meter-scale optics for amplification, beam steering, vacuum barriers, focusing, polarization rotation, and wavelength conversion. A multiphase program was put in place to increase the monthly optical manufacturing rate by up to 20x while simultaneously reducing cost by up to 3x through a sub-scale development, full-scale facilitization, and a pilot production phase. Currently 80% of the optics are complete with over 50% installed. In order to manufacture the high quality optics at desired manufacturing rate of over 100 precision optics per month, new more deterministic advanced fabrication technologies had to be employed over those used to manufacture previous fusion lasers.
Date: October 15, 2007
Creator: Stolz, C J
Object Type: Article
System: The UNT Digital Library
Hydrogen Production and Delivery Research (open access)

Hydrogen Production and Delivery Research

In response to DOE's Solicitation for Grant Applications DE-PS36-03GO93007, 'Hydrogen Production and Delivery Research', SRI International (SRI) proposed to conduct work under Technical Topic Area 5, Advanced Electrolysis Systems; Sub-Topic 5B, High-Temperature Steam Electrolysis. We proposed to develop a prototype of a modular industrial system for low-cost generation of H{sub 2} (<$2/kg) by steam electrolysis with anodic depolarization by CO. Water will be decomposed electrochemically into H{sub 2} and O{sub 2} on the cathode side of a high-temperature electrolyzer. Oxygen ions will migrate through an oxygen-ion-conductive solid oxide electrolyte. Gas mixtures on the cathode side (H{sub 2} + H{sub 2}O) and on the anode side (CO + CO{sub 2}) will be reliably separated by the solid electrolyte. Depolarization of the anodic process will decrease the electrolysis voltage, and thus the electricity required for H{sub 2} generation and the cost of produced H{sub 2}. The process is expected to be at least 10 times more energy-efficient than low-temperature electrolysis and will generate H{sub 2} at a cost of approximately $1-$1.5/kg. The operating economics of the system can be made even more attractive by deploying it at locations where waste heat is available; using waste heat would reduce the electricity required for …
Date: October 15, 2007
Creator: Balachov, Iouri
Object Type: Report
System: The UNT Digital Library
Oak Ridge National Laboratory Annual Progress Report for the Power Electronics and Electric Machinery Program (open access)

Oak Ridge National Laboratory Annual Progress Report for the Power Electronics and Electric Machinery Program

The U.S. Department of Energy (DOE) and the U.S. Council for Automotive Research (composed of automakers Ford, General Motors, and Chrysler) announced in January 2002 a new cooperative research effort. Known as FreedomCAR (derived from 'Freedom' and 'Cooperative Automotive Research'), it represents DOE's commitment to developing public/private partnerships to fund high-risk, high-payoff research into advanced automotive technologies. Efficient fuel cell technology, which uses hydrogen to power automobiles without air pollution, is a very promising pathway to achieve the ultimate vision. The new partnership replaces and builds upon the Partnership for a New Generation of Vehicles initiative that ran from 1993 through 2001. The Advanced Power Electronics and Electric Machines (APEEM) subprogram within the Vehicle Technologies Program provides support and guidance for many cutting-edge automotive technologies now under development. Research is focused on understanding and improving the way the various new components of tomorrow's automobiles will function as a unified system to improve fuel efficiency. In supporting the development of hybrid propulsion systems, the APEEM effort has enabled the development of technologies that will significantly improve advanced vehicle efficiency, costs, and fuel economy. The APEEM subprogram supports the efforts of the FreedomCAR and Fuel Partnership through a three-phase approach intended to: …
Date: October 15, 2008
Creator: Olszewski, M.
Object Type: Report
System: The UNT Digital Library
Porphyrin-Based Photocatalytic Lithography (open access)

Porphyrin-Based Photocatalytic Lithography

Photocatalytic lithography is an emerging technique that couples light with coated mask materials in order to pattern surface chemistry. We excite porphyrins to create radical species that photocatalytically oxidize, and thereby pattern, chemistries in the local vicinity. The technique advantageously does not necessitate mass transport or specified substrates, it is fast and robust and the wavelength of light does not limit the resolution of patterned features. We have patterned proteins and cells in order to demonstrate the utility of photocatalytic lithography in life science applications.
Date: October 15, 2007
Creator: Bearinger, J.; Stone, G.; Christian, A.; Dugan, L.; Hiddessen, A.; Wu, K. J. et al.
Object Type: Article
System: The UNT Digital Library
Computer Experiments for Function Approximations (open access)

Computer Experiments for Function Approximations

This research project falls in the domain of response surface methodology, which seeks cost-effective ways to accurately fit an approximate function to experimental data. Modeling and computer simulation are essential tools in modern science and engineering. A computer simulation can be viewed as a function that receives input from a given parameter space and produces an output. Running the simulation repeatedly amounts to an equivalent number of function evaluations, and for complex models, such function evaluations can be very time-consuming. It is then of paramount importance to intelligently choose a relatively small set of sample points in the parameter space at which to evaluate the given function, and then use this information to construct a surrogate function that is close to the original function and takes little time to evaluate. This study was divided into two parts. The first part consisted of comparing four sampling methods and two function approximation methods in terms of efficiency and accuracy for simple test functions. The sampling methods used were Monte Carlo, Quasi-Random LP{sub {tau}}, Maximin Latin Hypercubes, and Orthogonal-Array-Based Latin Hypercubes. The function approximation methods utilized were Multivariate Adaptive Regression Splines (MARS) and Support Vector Machines (SVM). The second part of the study …
Date: October 15, 2007
Creator: Chang, A; Izmailov, I; Rizzo, S.; Wynter, S; Alexandrov, O & Tong, C
Object Type: Report
System: The UNT Digital Library
Water adsorption on O(2x2)/Ru(0001) from STM experiments andfirst-principles calculations (open access)

Water adsorption on O(2x2)/Ru(0001) from STM experiments andfirst-principles calculations

We present a combined theoretical and experimental study of water adsorption on Ru(0001) pre-covered with 0.25 monolayers (ML) of oxygen forming a (2 x 2) structure. Several structures were analyzed by means of Density Functional Theory calculations for which STM simulations were performed and compared with experimental data. Up to 0.25 monolayers the molecules bind to the exposed Ru atoms of the 2 x 2 unit cell via the lone pair orbitals. The molecular plane is almost parallel to the surface with its H atoms pointing towards the chemisorbed O atoms of the 2 x 2 unit cell forming hydrogen bonds. The existence of these additional hydrogen bonds increases the adsorption energy of the water molecule to approximately 616 meV, which is {approx}220 meV more stable than on the clean Ru(0001) surface with a similar configuration. The binding energy shows only a weak dependence on water coverage, with a shallow minimum for a row structure at 0.125 ML. This is consistent with the STM experiments that show a tendency of the molecules to form linear rows at intermediate coverage. Our calculations also suggest the possible formation of water dimers near 0.25 ML.
Date: October 15, 2007
Creator: Cabrera-Sanfelix, P.; Sanchez-Portal, D.; Mugarza, A.; Shimizu,T.K.; Salmeron, M. & Arnau, A.
Object Type: Article
System: The UNT Digital Library
Final Technical Report (open access)

Final Technical Report

Most prokaryotes of interest to DOE are poorly understood. Even when full genomic sequences are available, the function of only a small number of gene products are clear. The critical question is how to best infer the most probable network architectures in cells that are poorly characterized. The project goal is to create a computational hypothesis testing (CHT) framework that combines large-scale dynamical simulation, a database of bioinformatics-derived probable interactions, and numerical parallel architecture data-fitting routines to explore many “what if ?” hypotheses about the functions of genes and proteins within pathways and their downstream effects on molecular concentration profiles and corresponding phenotypes. From this framework we expect to infer signal transduction pathways and gene expression networks in prokaryotes. Detailed mechanistic models of E. Coli have been developed that directly incorporate DNA sequence information. The CHT framework is implemented in the NIEngine network inference software. NIEngine has been applied to recover gene regulatory networks in E. coli to assess performance. Application to Shewanel la oneidensi and other organism of interest DOE will be conducted in partnership with Jim Collin's Lab at Boston University and other academic partners. The CHT framework has also found broad application in the automated learning of …
Date: October 15, 2008
Creator: Church, Bruce W
Object Type: Report
System: The UNT Digital Library
Simulations of plasma confinement in an antihydrogen trap (open access)

Simulations of plasma confinement in an antihydrogen trap

The three-dimensional particle-in-cell (3-D PIC) simulation code WARP is used to study positron confinement in antihydrogen traps. The magnetic geometry is close to that of a UC Berkeley experiment conducted, with electrons, as part of the ALPHA collaboration (W. Bertsche et al., AIP Conf. Proc. 796, 301 (2005)). In order to trap antihydrogen atoms, multipole magnetic fields are added to a conventional Malmberg-Penning trap. These multipole fields must be strong enough to confine the antihydrogen, leading to multipole field strengths at the trap wall comparable to those of the axial magnetic field. Numerical simulations reported here confirm recent experimental measurements of reduced particle confinement when a quadrupole field is added to a Malmberg-Penning trap. It is shown that, for parameters relevant to various antihydrogen experiments, the use of an octupole field significantly reducesthe positron losses seen with a quadrupole field. A unique method for obtaining a 3-D equilibrium of the positrons in the trap with a collisionless PIC code was developed especially for the study of the antihydrogen trap; however, it is of practical use for other traps as well.
Date: October 15, 2007
Creator: Gomberoff, K.; Fajans, J.; Friedman, A.; Grote, D.; Vay, J. L. & Wurtele, J. S.
Object Type: Article
System: The UNT Digital Library
Shotgun Metaproteomics of the Human Distal Gut Microbiota (open access)

Shotgun Metaproteomics of the Human Distal Gut Microbiota

The human gut contains a dense, complex and diverse microbial community, comprising the gut microbiome. Metagenomics has recently revealed the composition of genes in the gut microbiome, but provides no direct information about which genes are expressed or functioning. Therefore, our goal was to develop a novel approach to directly identify microbial proteins in fecal samples to gain information about the genes expressed and about key microbial functions in the human gut. We used a non-targeted, shotgun mass spectrometry-based whole community proteomics, or metaproteomics, approach for the first deep proteome measurements of thousands of proteins in human fecal samples, thus demonstrating this approach on the most complex sample type to date. The resulting metaproteomes had a skewed distribution relative to the metagenome, with more proteins for translation, energy production and carbohydrate metabolism when compared to what was earlier predicted from metagenomics. Human proteins, including antimicrobial peptides, were also identified, providing a non-targeted glimpse of the host response to the microbiota. Several unknown proteins represented previously undescribed microbial pathways or host immune responses, revealing a novel complex interplay between the human host and its associated microbes.
Date: October 15, 2008
Creator: VerBerkmoes, N. C.; Russell, A. L.; Shah, M.; Godzik, A.; Rosenquist, M.; Halfvarsson, J. et al.
Object Type: Article
System: The UNT Digital Library
PERC 2 High-End Computer System Performance: Scalable Science and Engineering (open access)

PERC 2 High-End Computer System Performance: Scalable Science and Engineering

During two years of SciDAC PERC-2, our activities had centered largely on development of new performance analysis techniques to enable efficient use on systems containing thousands or tens of thousands of processors. In addition, we continued our application engagement efforts and utilized our tools to study the performance of various SciDAC applications on a variety of HPC platforms.
Date: October 15, 2006
Creator: Reed, Daniel
Object Type: Report
System: The UNT Digital Library
Six-week time series of eddy covariance CO2 flux at Mammoth Mountain, California: performance evaluation and role of meteorological forcing (open access)

Six-week time series of eddy covariance CO2 flux at Mammoth Mountain, California: performance evaluation and role of meteorological forcing

CO{sub 2} and heat fluxes were measured over a six-week period (09/08/2006 to 10/24/2006) by the eddy covariance (EC) technique at the Horseshoe Lake tree kill (HLTK), Mammoth Mountain, CA, a site with complex terrain and high, spatially heterogeneous CO{sub 2} emission rates. EC CO{sub 2} fluxes ranged from 218 to 3500 g m{sup -2} d{sup -1} (mean = 1346 g m{sup -2} d{sup -1}). Using footprint modeling, EC CO{sub 2} fluxes were compared to CO{sub 2} fluxes measured by the chamber method on a grid repeatedly over a 10-day period. Half-hour EC CO{sub 2} fluxes were moderately correlated (R{sup 2} = 0.42) with chamber fluxes, whereas average-daily EC CO{sub 2} fluxes were well correlated (R{sup 2} = 0.70) with chamber measurements. Average daily EC CO{sub 2} fluxes were correlated with both average daily wind speed and atmospheric pressure; relationships were similar to those observed between chamber CO{sub 2} fluxes and the atmospheric parameters over a comparable time period. Energy balance closure was assessed by statistical regression of EC energy fluxes (sensible and latent heat) against available energy (net radiation, less soil heat flux). While incomplete (R{sup 2} = 0.77 for 1:1 line), the degree of energy balance closure fell …
Date: October 15, 2007
Creator: Lewicki, Jennifer; Lewicki, J. L.; Fischer, M. L. & Hilley, G. E.
Object Type: Article
System: The UNT Digital Library
Toward a more robust variance-based global sensitivity analysis of model outputs (open access)

Toward a more robust variance-based global sensitivity analysis of model outputs

Global sensitivity analysis (GSA) measures the variation of a model output as a function of the variations of the model inputs given their ranges. In this paper we consider variance-based GSA methods that do not rely on certain assumptions about the model structure such as linearity or monotonicity. These variance-based methods decompose the output variance into terms of increasing dimensionality called 'sensitivity indices', first introduced by Sobol' [25]. Sobol' developed a method of estimating these sensitivity indices using Monte Carlo simulations. McKay [13] proposed an efficient method using replicated Latin hypercube sampling to compute the 'correlation ratios' or 'main effects', which have been shown to be equivalent to Sobol's first-order sensitivity indices. Practical issues with using these variance estimators are how to choose adequate sample sizes and how to assess the accuracy of the results. This paper proposes a modified McKay main effect method featuring an adaptive procedure for accuracy assessment and improvement. We also extend our adaptive technique to the computation of second-order sensitivity indices. Details of the proposed adaptive procedure as wells as numerical results are included in this paper.
Date: October 15, 2007
Creator: Tong, C
Object Type: Report
System: The UNT Digital Library
Simple Models and Methods for Estimating the UltrasonicReflectivity of Spot Welds (open access)

Simple Models and Methods for Estimating the UltrasonicReflectivity of Spot Welds

This paper describes models and methods for estimating theacoustic reflectivity of the welded interfaces between spot-welded sheetsfrom normal-incidence pulse-echo ultrasound signals. The simple geometryof the problem allows an abstraction that does not resort to complex waveequations. Instead, a reflectivity model predicts the timing andamplitude of the echoes arriving at the probe. This reflectivity model isnested in a signal processing model; recovering reflectivity firstrequires deconvolution to recover discrete impulses from the probesignal, then processing these with the reflectivity model. Reflectivitymaps of spot welds generated with this model show promise for predictingweld quality.
Date: October 15, 2006
Creator: Davis, William B.
Object Type: Article
System: The UNT Digital Library
CH-TRU Content Codes (CH-TRUCON) (open access)

CH-TRU Content Codes (CH-TRUCON)

The CH-TRU Waste Content Codes (CH-TRUCON) document describes the inventory of the U.S. Department of Energy (DOE) CH-TRU waste within the transportation parameters specified by the Contact-Handled Transuranic Waste Authorized Methods for Payload Control (CH-TRAMPAC). The CH-TRAMPAC defines the allowable payload for the Transuranic Package Transporter-II (TRUPACT-II) and HalfPACT packagings. This document is a catalog of TRUPACT-II and HalfPACT authorized contents and a description of the methods utilized to demonstrate compliance with the CH-TRAMPAC. A summary of currently approved content codes by site is presented in Table 1. The CH-TRAMPAC describes "shipping categories" that are assigned to each payload container. Multiple shipping categories may be assigned to a single content code. A summary of approved content codes and corresponding shipping categories is provided in Table 2, which consists of Tables 2A, 2B, and 2C. Table 2A provides a summary of approved content codes and corresponding shipping categories for the "General Case," which reflects the assumption of a 60-day shipping period as described in the CH-TRAMPAC and Appendix 3.4 of the CH-TRU Payload Appendices. For shipments to be completed within an approximately 1,000-mile radius, a shorter shipping period of 20 days is applicable as described in the CH-TRAMPAC and Appendix 3.5 …
Date: October 15, 2005
Creator: Westinghouse TRU Solutions LLC
Object Type: Report
System: The UNT Digital Library
Evaluation and Characterization of Magnets and Capacitors (open access)

Evaluation and Characterization of Magnets and Capacitors

Advanced vehicle, fuel cell, hybrid electric vehicle (HEV), and plug in hybrid research and development is conducted by the U.S. Department of Energy (DOE) through its FreedomCAR and Vehicle Technologies (FCVT) program. The mission of this program is to develop more energy efficient and environmentally safe highway transportation technologies. Program activities include research, development, testing, technology validation, and technology transfer. These activities are done at the system and component levels. This report will discuss component level testing of prototype capacitors and magnets. As capacitor and magnet technologies mature, it is important to ascertain the limitations of these new technologies by subjecting the components to standardized tests to evaluate their capabilities. Test results will assist in the determination of their ability to provide improvements in power electronics and motor designs to meet the FCVT goals.
Date: October 15, 2006
Creator: Seiber, L. E.; Cunningham, J. P.; Golik, S. S. & Armstrong, G.
Object Type: Report
System: The UNT Digital Library
Decisive role of the energetics of dissociation products in the adsorption of water on O/Ru(0001) (open access)

Decisive role of the energetics of dissociation products in the adsorption of water on O/Ru(0001)

Using density-functional theory they found that, depending on coverage, coadsorbed oxygen can act both as a promoter and as an inhibitor of the dissociation of water on Ru(0001), the transition between these two behaviors occurring at (0.2 M). The key factor that determines this transition is the adsorption energy of the reaction products, OH in particular. The chemistry of this coadsorbed system is dictated by the effective coordination of the Ru atoms that participate in the bonding of the different species. In particular, they observed that a low coverage of oxygen increases the adsorption energy of the OH fraction on the Ru surface. This surprising extra stabilization of the OH with the coadsorption of oxygen can be understood in the context of the metallic bonding and could well correspond to a general trend for the coadsorption of electronegative species on metallic surfaces.
Date: October 15, 2008
Creator: Cabrera-Sanfelix, Pepa; Arnau, Andres; Mugarza, Aitor; Shimizu, Tomoko K.; Salmeron, Miquel & Sánchez-Portal, Daniel
Object Type: Article
System: The UNT Digital Library
Realization of a Custom Designed FPGA Based Embedded Controller (open access)

Realization of a Custom Designed FPGA Based Embedded Controller

As part of the Low Level RF (LLRF) upgrade project at Brookhaven National Laboratory's Collider-Accelerator Department (BNL C-AD), we have recently developed and tested a prototype high performance embedded controller. This controller is a custom designed PMC module employing a Xilinx V4FX60 FPGA with a PowerPC405 embedded processor, and a wide variety of on board peripherals (DDR2 SDRAM, FLASH, Ethernet, PCI, multi-gigabit serial transceivers, etc.). The controller is capable of running either an embedded version of LINUX or VxWorks, the standard operating system for RHIC front end computers (FECs). We have successfully demonstrated functionality of this controller as a standard RHIC FEC and tested all on board peripherals. We now have the ability to develop complex, custom digital controllers within the framework of the standard RHIC control system infrastructure. This paper will describe various aspects of this development effort, including the basic hardware, functional capabilities, the development environment, kernel and system integration, and plans for further development.
Date: October 15, 2007
Creator: Severino, F.; Harvey, M.; Hayes, T.; Hoff, L.; Oddo, P. & Smith, K. S.
Object Type: Article
System: The UNT Digital Library