Resource Type

Efficient multiband and broadband cross polarization converters based on slotted Lshaped nanoantennas (open access)

Efficient multiband and broadband cross polarization converters based on slotted Lshaped nanoantennas

This article presents highly efficient reflective cross polarization converters based on metamaterials operating in the infrared regime.
Date: November 14, 2014
Creator: Ding, Jun; Arigong, Bayaner; Ren, Han; Zhou, Mi; Shao, Jin; Lin, Yuankun et al.
System: The UNT Digital Library
Enhanced Superconducting Gaps in Trilayer High-Temperature Bi (2) Sr (2) Ca (2) Cu (3) O (10+delta) Cuprate Superconductor (open access)

Enhanced Superconducting Gaps in Trilayer High-Temperature Bi (2) Sr (2) Ca (2) Cu (3) O (10+delta) Cuprate Superconductor

None
Date: November 14, 2012
Creator: Ideta, S.; Takashima, K.; Hashimoto, M.; Yoshida, T.; Fujimori, A.; Anzai, H. et al.
System: The UNT Digital Library
The Network Completion Problem: Inferring Missing Nodes and Edges in Networks (open access)

The Network Completion Problem: Inferring Missing Nodes and Edges in Networks

Network structures, such as social networks, web graphs and networks from systems biology, play important roles in many areas of science and our everyday lives. In order to study the networks one needs to first collect reliable large scale network data. While the social and information networks have become ubiquitous, the challenge of collecting complete network data still persists. Many times the collected network data is incomplete with nodes and edges missing. Commonly, only a part of the network can be observed and we would like to infer the unobserved part of the network. We address this issue by studying the Network Completion Problem: Given a network with missing nodes and edges, can we complete the missing part? We cast the problem in the Expectation Maximization (EM) framework where we use the observed part of the network to fit a model of network structure, and then we estimate the missing part of the network using the model, re-estimate the parameters and so on. We combine the EM with the Kronecker graphs model and design a scalable Metropolized Gibbs sampling approach that allows for the estimation of the model parameters as well as the inference about missing nodes and edges of …
Date: November 14, 2011
Creator: Kim, M & Leskovec, J
System: The UNT Digital Library
Life extension program for the modular caustic side solvent extraction unit at Savannah River Site (open access)

Life extension program for the modular caustic side solvent extraction unit at Savannah River Site

Caustic Side Solvent Extraction (CSSX) is currently used at the U.S. Department of Energy (DOE) Savannah River Site (SRS) for removal of cesium from the high-level salt-wastes stored in underground tanks. At SRS, the CSSX process is deployed in the Modular CSSX Unit (MCU). The CSSX technology utilizes a multi-component organic solvent and annular centrifugal contactors to extract cesium from alkaline salt waste. Coalescers and decanters process the Decontaminated Salt Solution (DSS) and Strip Effluent (SE) streams to allow recovery and reuse of the organic solvent and to limit the quantity of solvent transferred to the downstream facilities. MCU is operated in series with the Actinide Removal Process (ARP) which removes strontium and actinides from salt waste utilizing monosodium titanate. ARP and MCU were developed and implemented as interim salt processing until future processing technology, the CSSX-based Salt Waste Processing Facility (SWPF), is operational. SWPF is slated to come on-line in October 2014. The three year design life of the ARP/MCU process, however, was reached in April 2011. Nevertheless, most of the individual process components are capable of operating longer. An evaluation determined ARP/MCU can operate until 2015 before major equipment failure is expected. The three year design life of …
Date: November 14, 2012
Creator: Samadi-Dezfouli, Azadeh
System: The UNT Digital Library
Lessons Learned From The 200 West Pump And Treatment Facility Construction Project At The US DOE Hanford Site - A Leadership For Energy And Environmental Design (LEED) Gold-Certified Facility (open access)

Lessons Learned From The 200 West Pump And Treatment Facility Construction Project At The US DOE Hanford Site - A Leadership For Energy And Environmental Design (LEED) Gold-Certified Facility

CH2M Hill Plateau Remediation Company (CHPRC) designed, constructed, commissioned, and began operation of the largest groundwater pump and treatment facility in the U.S. Department of Energy's (DOE) nationwide complex. This one-of-a-kind groundwater pump and treatment facility, located at the Hanford Nuclear Reservation Site (Hanford Site) in Washington State, was built in an accelerated manner with American Recovery and Reinvestment Act (ARRA) funds and has attained Leadership in Energy and Environmental Design (LEED) GOLD certification, which makes it the first non-administrative building in the DOE Office of Environmental Management complex to earn such an award. There were many contractual, technical, configuration management, quality, safety, and LEED challenges associated with the design, procurement, construction, and commissioning of this $95 million, 52,000 ft groundwater pump and treatment facility. This paper will present the Project and LEED accomplishments, as well as Lessons Learned by CHPRC when additional ARRA funds were used to accelerate design, procurement, construction, and commissioning of the 200 West Groundwater Pump and Treatment (2W P&T) Facility to meet DOE's mission of treating contaminated groundwater at the Hanford Site with a new facility by June 28, 2012.
Date: November 14, 2012
Creator: Dorr, Kent A.; Ostrom, Michael J. & Freeman-Pollard, Jhivaun R.
System: The UNT Digital Library
Essay: In Memory of Robert Siemann (open access)

Essay: In Memory of Robert Siemann

Bob Siemann came to SLAC from Cornell in 1991. With the support from Burton Richter, then Director of SLAC, he took on a leadership role to formulate an academic program in accelerator physics at SLAC and the development of its accelerator faculty. Throughout his career he championed accelerator physics as an independent academic discipline, a vision that he fought so hard for and never retreated from. He convinced Stanford University and SLAC to create a line of tenured accelerator physics faculty and over the years he also regularly taught classes at Stanford and the U.S. Particle Accelerator School. After the shutdown of the SSC Laboratory, I returned to SLAC in 1993 to join the accelerator faculty he was forming. He had always visualized a need to have a professional academic journal for the accelerator field, and played a pivotal role in creating the journal Physical Review Special Topics - Accelerators and Beams, now the community standard for accelerator physics after nine years of his editorship. Today, Bob's legacy of accelerator physics as an independent academic discipline continues at SLAC as well as in the community, from which we all benefit. Bob was a great experimentalist. He specialized in experimental techniques …
Date: November 14, 2011
Creator: Chao, Alexander W.
System: The UNT Digital Library
Essay: Robert H. Siemann As Leader of the Advanced Accelerator Research Department (open access)

Essay: Robert H. Siemann As Leader of the Advanced Accelerator Research Department

Robert H. Siemann originally conceived of the Advanced Accelerator Research Department (AARD) as an academic, experimental group dedicated to probing the technical limitations of accelerators while providing excellent educational opportunities for young scientists. The early years of the Accelerator Research Department B, as it was then known, were dedicated to a wealth of mostly student-led experiments to examine the promise of advanced accelerator techniques. High-gradient techniques including millimeter-wave rf acceleration, beam-driven plasma acceleration, and direct laser acceleration were pursued, including tests of materials under rf pulsed heating and short-pulse laser radiation, to establish the ultimate limitations on gradient. As the department and program grew, so did the motivation to found an accelerator research center that brought experimentalists together in a test facility environment to conduct a broad range of experiments. The Final Focus Test Beam and later the Next Linear Collider Test Accelerator provided unique experimental facilities for AARD staff and collaborators to carry out advanced accelerator experiments. Throughout the evolution of this dynamic program, Bob maintained a department atmosphere and culture more reminiscent of a university research group than a national laboratory department. His exceptional ability to balance multiple roles as scientist, professor, and administrator enabled the creation and …
Date: November 14, 2011
Creator: Colby, Eric R. & Hogan, Mark J.
System: The UNT Digital Library
ILC Instrumentation R&D at SCIPP (open access)

ILC Instrumentation R&D at SCIPP

The Santa Cruz Institute for Particle Physics (SCIPP) continues to be engaged in research and development towards an ILC detector. The latest efforts at SCIPP are described, including those associated with the LSTFE front-end readout ASIC, the use of charge division to obtain a longitudinal coordinate from silicon strip detectors, and the contribution of strip resistance to readout noise.
Date: November 14, 2011
Creator: Carman, J.; Crosby, S.; Fadeyev, V.; Partridge, R.; Schumm, B. A.; Spencer, N. et al.
System: The UNT Digital Library
Community Petascale Project for Accelerator Science and Simulation: Advancing Computational Science for Future Accelerators and Accelerator Technologies (open access)

Community Petascale Project for Accelerator Science and Simulation: Advancing Computational Science for Future Accelerators and Accelerator Technologies

The design and performance optimization of particle accelerators are essential for the success of the DOE scientific program in the next decade. Particle accelerators are very complex systems whose accurate description involves a large number of degrees of freedom and requires the inclusion of many physics processes. Building on the success of the SciDAC-1 Accelerator Science and Technology project, the SciDAC-2 Community Petascale Project for Accelerator Science and Simulation (ComPASS) is developing a comprehensive set of interoperable components for beam dynamics, electromagnetics, electron cooling, and laser/plasma acceleration modelling. ComPASS is providing accelerator scientists the tools required to enable the necessary accelerator simulation paradigm shift from high-fidelity single physics process modeling (covered under SciDAC1) to high-fidelity multiphysics modeling. Our computational frameworks have been used to model the behavior of a large number of accelerators and accelerator R&D experiments, assisting both their design and performance optimization. As parallel computational applications, the ComPASS codes have been shown to make effective use of thousands of processors. ComPASS is in the first year of executing its plan to develop the next-generation HPC accelerator modeling tools. ComPASS aims to develop an integrated simulation environment that will utilize existing and new accelerator physics modules with petascale capabilities, …
Date: November 14, 2011
Creator: Spentzouris, P.; /Fermilab; Cary, J.; /Tech-X, Boulder; McInnes, L.C.; /Argonne et al.
System: The UNT Digital Library
Measurement of Charmless B to Vector-Vector decays at BaBar (open access)

Measurement of Charmless B to Vector-Vector decays at BaBar

The authors present results of B {yields} vector-vector (VV) and B {yields} vector-axial vector (VA) decays B{sup 0} {yields} {phi}X(X = {phi},{rho}{sup +} or {rho}{sup 0}), B{sup +} {yields} {phi}K{sup (*)+}, B{sup 0} {yields} K*K*, B{sup 0} {yields} {rho}{sup +}b{sub 1}{sup -} and B{sup +} {yields} K*{sup 0}{alpha}{sub 1}{sup +}. The largest dataset used for these results is based on 465 x 10{sup 6} {Upsilon}(4S) {yields} B{bar B} decays, collected with the BABAR detector at the PEP-II B meson factory located at the Stanford Linear Accelerator Center (SLAC). Using larger datasets, the BABAR experiment has provided more precise B {yields} VV measurements, further supporting the smaller than expected longitudinal polarization fraction of B {yields} {phi}K*. Additional B meson to vector-vector and vector-axial vector decays have also been studied with a view to shedding light on the polarization anomaly. Taking into account the available errors, we find no disagreement between theory and experiment for these additional decays.
Date: November 14, 2011
Creator: Olaiya, Emmanuel & /Rutherford
System: The UNT Digital Library
Non-Gaussianity as a Probe of the Physics of the Primordial Universe and the Astrophysics of the Low Redshift Universe (open access)

Non-Gaussianity as a Probe of the Physics of the Primordial Universe and the Astrophysics of the Low Redshift Universe

A new and powerful probe of the origin and evolution of structures in the Universe has emerged and been actively developed over the last decade. In the coming decade, non-Gaussianity, i.e., the study of non-Gaussian contributions to the correlations of cosmological fluctuations, will become an important probe of both the early and the late Universe. Specifically, it will play a leading role in furthering our understanding of two fundamental aspects of cosmology and astrophysics: (1) The physics of the very early universe that created the primordial seeds for large-scale structures, and (2) The subsequent growth of structures via gravitational instability and gas physics at later times. To date, observations of fluctuations in the Cosmic Microwave Background (CMB) and the Large-Scale Structure of the Universe (LSS) have focused largely on the Gaussian contribution as measured by the two-point correlations (or the power spectrum) of density fluctuations. However, an even greater amount of information is contained in non-Gaussianity and a large discovery space therefore still remains to be explored. Many observational probes can be used to measure non-Gaussianity, including CMB, LSS, gravitational lensing, Lyman-{alpha} forest, 21-cm fluctuations, and the abundance of rare objects such as clusters of galaxies and high-redshift galaxies. Not …
Date: November 14, 2011
Creator: Komatsu, E.; Afshordi, N.; Bartolo, N.; Baumann, D.; Bond, J. R.; Buchbinder, E. I. et al.
System: The UNT Digital Library
Wide-Field Astronomical Surveys in the Next Decade (open access)

Wide-Field Astronomical Surveys in the Next Decade

Wide-angle surveys have been an engine for new discoveries throughout the modern history of astronomy, and have been among the most highly cited and scientifically productive observing facilities in recent years. This trend is likely to continue over the next decade, as many of the most important questions in astrophysics are best tackled with massive surveys, often in synergy with each other and in tandem with the more traditional observatories. We argue that these surveys are most productive and have the greatest impact when the data from the surveys are made public in a timely manner. The rise of the 'survey astronomer' is a substantial change in the demographics of our field; one of the most important challenges of the next decade is to find ways to recognize the intellectual contributions of those who work on the infrastructure of surveys (hardware, software, survey planning and operations, and databases/data distribution), and to make career paths to allow them to thrive.
Date: November 14, 2011
Creator: Strauss, Michael A.; Tyson, J. Anthony; Anderson, Scott F.; Axelrod, T. S.; Becker, Andrew C.; Bickerton, Steven J. et al.
System: The UNT Digital Library
Update on Angles and Sides of the CKM Unitarity Triangle from BaBar (open access)

Update on Angles and Sides of the CKM Unitarity Triangle from BaBar

We report several recent updates from the BABAR Collaboration on the matrix elements |V{sub cb}|, |V{sub ub}|, and |V{sub td}| of the Cabibbo-Kobayashi-Maskawa (CKM) quark-mixing matrix, and the angles {beta} and {alpha} of the unitarity triangle. Most results presented here are using the full BABAR {Upsilon}(4S) data set.
Date: November 14, 2011
Creator: Cheng, Chih-hsiang & /Caltech
System: The UNT Digital Library
Open String Wavefunctions in Warped Compactifications (open access)

Open String Wavefunctions in Warped Compactifications

None
Date: November 14, 2011
Creator: Marchesano, Fernando; McGuirk, Paul & Shiu, Gary
System: The UNT Digital Library
Curved Mesh Correction And Adaptation Tool to Improve COMPASS Electromagnetic Analyses (open access)

Curved Mesh Correction And Adaptation Tool to Improve COMPASS Electromagnetic Analyses

SLAC performs large-scale simulations for the next-generation accelerator design using higher-order finite elements. This method requires using valid curved meshes and adaptive mesh refinement in complex 3D curved domains to achieve its fast rate of convergence. ITAPS has developed a procedure to address those mesh requirements to enable petascale electromagnetic accelerator simulations by SLAC. The results demonstrate that those correct valid curvilinear meshes can not only make the simulation more reliable but also improve computational efficiency up to 30%. This paper presents a procedure to track moving adaptive mesh refinement in curved domains. The procedure is capable of generating suitable curvilinear meshes to enable large-scale accelerator simulations. The procedure can generate valid curved meshes with substantially fewer elements to improve the computational efficiency and reliability of the COMPASS electromagnetic analyses. Future work will focus on the scalable parallelization of all steps for petascale simulations.
Date: November 14, 2011
Creator: Luo, X.; Shephard, M.; Lee, L. Q.; Ng, C. & Ge, L.
System: The UNT Digital Library
Focused ion beam patterned Fe thin films A study by selective area Stokes polarimetry and soft x-Ray microscopy (open access)

Focused ion beam patterned Fe thin films A study by selective area Stokes polarimetry and soft x-Ray microscopy

We demonstrate the potential to modify the magnetic behavior and structural properties of ferromagnetic thin films using focused ion beam 'direct-write' lithography. Patterns inspired by the split-ring resonators often used as components in meta-materials were defined upon 15 nm Fe films using a 30 keV Ga{sup +} focused ion beam at a dose of 2 x 10{sup 16} ions cm{sup -2}. Structural, chemical and magnetic changes to the Fe were studied using transmission soft X-ray microscopy at the ALS, Berkeley CA. X-ray absorption spectra showed a 23% reduction in the thickness of the film in the Ga irradiated areas, but no chemical change to the Fe was evident. X-ray images of the magnetic reversal process show domain wall pinning around the implanted areas, resulting in an overall increase in the coercivity of the film. Transmission electron microscopy showed significant grain growth in the implanted regions.
Date: November 14, 2010
Creator: Cook, P. J.; Shen, T. H.; Grundy, P. J.; Im, M.-Y.; Fischer, P.; Morton, S. A. et al.
System: The UNT Digital Library
Essay: Bob Siemann-SLC Days at SLAC (open access)

Essay: Bob Siemann-SLC Days at SLAC

Bob Siemann was a great experimentalist and an excellent teacher.We will greatly miss him. Bob came to SLAC in early 1991 to work on the Stanford Linear Collider (SLC). The SLC was a challenging accelerator which began operating in the late 1980's but still had numerous obstacles to be overcome years into operation. One of the compounding difficulties was making reproducible measurements, since the stability of the collider was poor and the diagnostics were insufficient. Bob dove into this challenge and helped design experiments and diagnostics that provided further clarity. I first got to know Bob while I was still a graduate student, trying to finish my thesis and performing some experimental studies on the SLC, which, at the time, was proving to be very difficult. Most of my expertise had been in beam theory and simulation. Dealing with the real issues of the accelerator was challenging. Bob helped me understand the difference between systematic and statistical errors, and separate operational issues from the fundamental physics. His way of teaching was not to provide an explanation but to ask enough questions so that I could find the answer on my own - this was the best way to learn. I …
Date: November 14, 2011
Creator: Raubenheimer, Tor O.
System: The UNT Digital Library
Radiative and Leptonic B-meson Decays from the B-factories (open access)

Radiative and Leptonic B-meson Decays from the B-factories

Radiative and leptonic decays of B-mesons represent an excellent laboratory for the search for New Physics. I present here recent results on radiative and leptonic decays from the Belle and BABAR collaborations. Radiative penguin and leptonic B-meson decays are excellent probes for investigating the effects of New Physics. Although current measurements are in agreement with the Standard Model expectations, they are still quite useful for setting bounds on possible NP models. The B {yields} X{sub s}{gamma} and B {yields} {tau}{nu} measurements, for example, put strong constraints on the mass of charged Higgs bosons in Type II two-Higgs double models. The B {yields} X{sub s}{gamma} branching fraction measurements also constrain models with universal extra dimensions.
Date: November 14, 2011
Creator: Walsh, John
System: The UNT Digital Library
SciDAC Advances in Beam Dynamics Simulation: From Light Sources to Colliders (open access)

SciDAC Advances in Beam Dynamics Simulation: From Light Sources to Colliders

In this paper, we report on progress that has been made in beam dynamics simulation, from light sources to colliders, during the first year of the SciDAC-2 accelerator project 'Community Petascale Project for Accelerator Science and Simulation (ComPASS).' Several parallel computational tools for beam dynamics simulation are described. Also presented are number of applications in current and future accelerator facilities (e.g., LCLS, RHIC, Tevatron, LHC, and ELIC). Particle accelerators are some of most important tools of scientific discovery. They are widely used in high-energy physics, nuclear physics, and other basic and applied sciences to study the interaction of elementary particles, to probe the internal structure of matter, and to generate high-brightness radiation for research in materials science, chemistry, biology, and other fields. Modern accelerators are complex and expensive devices that may be several kilometers long and may consist of thousands of beamline elements. An accelerator may transport trillions of charged particles that interact electromagnetically among themselves, that interact with fields produced by the accelerator components, and that interact with beam-induced fields. Large-scale beam dynamics simulations on massively parallel computers can help provide understanding of these complex physical phenomena, help minimize design cost, and help optimize machine operation. In this paper, …
Date: November 14, 2011
Creator: Qiang, J.; Borland, M.; Kabel, A.; Li, R.; Ryne, R.; Stern, E. et al.
System: The UNT Digital Library
Discovery of GeV Emission tfrom the Circinus Galaxy with the Fermi-Lat (open access)

Discovery of GeV Emission tfrom the Circinus Galaxy with the Fermi-Lat

None
Date: November 14, 2013
Creator: Hayashida, Masaaki; Stawarz, Lukasz; Cheung, Chi C.; Bechtol, Keith; Madejski, Greg M.; Ajello, Marco et al.
System: The UNT Digital Library
The Lancet Countdown: tracking progress on health and climate change (open access)

The Lancet Countdown: tracking progress on health and climate change

This article outlines the potential indicators and indicator domains to be tracked by the Lancet Countdown working groups, with suggestions on the methodologies and datasets available to achieve this end.
Date: November 14, 2016
Creator: Watts, Nick; Adger, W. Neil; Ayeb-Karlsson, Sonja; Bai, Yuqi; Byass, Peter; Campbell-Lendrum, Diarmid et al.
System: The UNT Digital Library
Proliferation Resistance and Physical Protection Working Group: Methodology and Applications (open access)

Proliferation Resistance and Physical Protection Working Group: Methodology and Applications

We summarize the technical progress and accomplishments on the evaluation methodology for proliferation resistance and physical protection (PR and PP) of Generation IV nuclear energy systems. We intend the results of the evaluations performed with the methodology for three types of users: system designers, program policy makers, and external stakeholders. The PR and PP Working Group developed the methodology through a series of demonstration and case studies. Over the past few years various national and international groups have applied the methodology to nuclear energy system designs as well as to developing approaches to advanced safeguards.
Date: November 14, 2012
Creator: Bari, Robert A.; Whitlock, Jeremy; Therios, Ike U. & Peterson, Per F.
System: The UNT Digital Library
End-to-End Network QoS via Scheduling of Flexible Resource Reservation Requests (open access)

End-to-End Network QoS via Scheduling of Flexible Resource Reservation Requests

Modern data-intensive applications move vast amounts of data between multiple locations around the world. To enable predictable and reliable data transfer, next generation networks allow such applications to reserve network resources for exclusive use. In this paper, we solve an important problem (called SMR3) to accommodate multiple and concurrent network reservation requests between a pair of end-sites. Given the varying availability of bandwidth within the network, our goal is to accommodate as many reservation requests as possible while minimizing the total time needed to complete the data transfers. We first prove that SMR3 is an NP-hard problem. Then we solve it by developing a polynomial-time heuristic, called RRA. The RRA algorithm hinges on an efficient mechanism to accommodate large number of requests by minimizing the bandwidth wastage. Finally, via numerical results, we show that RRA constructs schedules that accommodate significantly larger number of requests compared to other, seemingly efficient, heuristics.
Date: November 14, 2011
Creator: Sharma, S.; Katramatos, D. & Yu, D.
System: The UNT Digital Library
D0 - D0bar Mixing: An Overview (open access)

D0 - D0bar Mixing: An Overview

Recently, the B factory experiments BABAR and Belle as well as the CDF collaboration found evidence for mixing in the D meson system. The current status (beginning of summer 2008) of the experimental results of D{sup 0} mixing is summarized. In this paper, we present an overview of D{sup 0} mixing. After an introduction to the charm mixing phenomenology and analysis techniques, results of the mixing parameters and CP violation as related to mixing are summarized. They are obtained from hadronic two-body, multi-body final states and from quantum correlated D{sup 0} decays of the experiments BABAR, Belle, Cleo and CDF. Mixing results from semileptonic D{sup 0} decays can be found elsewhere.
Date: November 14, 2011
Creator: Marks, Jorg & U., /Heidelberg
System: The UNT Digital Library