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Clouds and Chemistry in the Atmosphere of Extrasolar Planet HR8799b (open access)

Clouds and Chemistry in the Atmosphere of Extrasolar Planet HR8799b

Using the integral field spectrograph OSIRIS, on the Keck II telescope, broad near-infrared H and K-band spectra of the young exoplanet HR8799b have been obtained. In addition, six new narrow-band photometric measurements have been taken across the H and K bands. These data are combined with previously published photometry for an analysis of the planet's atmospheric properties. Thick photospheric dust cloud opacity is invoked to explain the planet's red near-IR colors and relatively smooth near-IR spectrum. Strong water absorption is detected, indicating a Hydrogen-rich atmosphere. Only weak CH{sub 4} absorption is detected at K band, indicating efficient vertical mixing and a disequilibrium CO/CH{sub 4} ratio at photospheric depths. The H-band spectrum has a distinct triangular shape consistent with low surface gravity. New giant planet atmosphere models are compared to these data with best fitting bulk parameters, T{sub eff} = 1100K {+-} 100 and log(g) = 3.5 {+-} 0.5 (for solar composition). Given the observed luminosity (log L{sub obs}/L{sub {circle_dot}} {approx} -5.1), these values correspond to a radius of 0.75 R{sub Jup{sub 0.12}{sup +0.17}} and mass {approx} 0.72 M{sub Jup{sub -0.6}{sup +2.6}} - strikingly inconsistent with interior/evolution models. Enhanced metallicity (up to {approx} 10 x that of the Sun) along with …
Date: March 21, 2011
Creator: Barman, T. S.; Macintosh, B. A.; Konopacky, Q. M. & Marois, C.
System: The UNT Digital Library
DUK - A Fast and Efficient Kmer Based Sequence Matching Tool (open access)

DUK - A Fast and Efficient Kmer Based Sequence Matching Tool

A new tool, DUK, is developed to perform matching task. Matching is to find whether a query sequence partially or totally matches given reference sequences or not. Matching is similar to alignment. Indeed many traditional analysis tasks like contaminant removal use alignment tools. But for matching, there is no need to know which bases of a query sequence matches which position of a reference sequence, it only need know whether there exists a match or not. This subtle difference can make matching task much faster than alignment. DUK is accurate, versatile, fast, and has efficient memory usage. It uses Kmer hashing method to index reference sequences and Poisson model to calculate p-value. DUK is carefully implemented in C++ in object oriented design. The resulted classes can also be used to develop other tools quickly. DUK have been widely used in JGI for a wide range of applications such as contaminant removal, organelle genome separation, and assembly refinement. Many real applications and simulated dataset demonstrate its power.
Date: March 21, 2011
Creator: Li, Mingkun; Copeland, Alex & Han, James
System: The UNT Digital Library
New Low Emittance Lattice for the Super-B Accelerator (open access)

New Low Emittance Lattice for the Super-B Accelerator

New low emittance lattices have been designed for the asymmetric SuperB accelerator, aiming at a luminosity of 10{sup 36} cm{sup -2} s{sup -1}. Main optics features are two alternating arc cells with different horizontal phase advance, decreasing beam emittance and allowing at the same time for easy chromaticity correction in the arcs. Emittance can be further reduced by a factor of two for luminosity upgrade. Spin rotation schemes for the e{sup -} beam have been studied to provide longitudinal polarization at the IP, and implementation into the lattice is in progress.
Date: October 21, 2011
Creator: Biagini, M.E.; Boscolo, M.; Raimondi, P.; Tomassini, S.; Zobov, M.; /Frascati et al.
System: The UNT Digital Library
Study of wavelength-shifting chemicals for use in large-scale water Cherenkov detectors (open access)

Study of wavelength-shifting chemicals for use in large-scale water Cherenkov detectors

Cherenkov detectors employ various methods to maximize light collection at the photomultiplier tubes (PMTs). These generally involve the use of highly reflective materials lining the interior of the detector, reflective materials around the PMTs, or wavelength-shifting sheets around the PMTs. Recently, the use of water-soluble wavelength-shifters has been explored to increase the measurable light yield of Cherenkov radiation in water. These wave-shifting chemicals are capable of absorbing light in the ultravoilet and re-emitting the light in a range detectable by PMTs. Using a 250 L water Cherenkov detector, we have characterized the increase in light yield from three compounds in water: 4-Methylumbelliferone, Carbostyril-124, and Amino-G Salt. We report the gain in PMT response at a concentration of 1 ppm as: 1.88 {+-} 0.02 for 4-Methylumbelliferone, stable to within 0.5% over 50 days, 1.37 {+-} 0.03 for Carbostyril-124, and 1.20 {+-} 0.02 for Amino-G Salt. The response of 4-Methylumbelliferone was modeled, resulting in a simulated gain within 9% of the experimental gain at 1 ppm concentration. Finally, we report an increase in neutron detection performance of a large-scale (3.5 kL) gadolinium-doped water Cherenkov detector at a 4-Methylumbelliferone concentration of 1 ppm.
Date: September 21, 2011
Creator: Sweany, M; Bernstein, A; Dazeley, S; Dunmore, J; Felde, J; Svoboda, R et al.
System: The UNT Digital Library
Portal 6.0 Released!! (open access)

Portal 6.0 Released!!

None
Date: March 21, 2011
Creator: Cantor, Michael & Smirnova, Tatyana
System: The UNT Digital Library
Distinguishing Realistic Military Blasts from Firecrackers in Mitigation Studies of Blast Induced Traumatic Brain Injury (open access)

Distinguishing Realistic Military Blasts from Firecrackers in Mitigation Studies of Blast Induced Traumatic Brain Injury

In their Contributed Article, Nyein et al. (1,2) present numerical simulations of blast waves interacting with a helmeted head and conclude that a face shield may significantly mitigate blast induced traumatic brain injury (TBI). A face shield may indeed be important for future military helmets, but the authors derive their conclusions from a much smaller explosion than typically experienced on the battlefield. The blast from the 3.16 gm TNT charge of (1) has the following approximate peak overpressures, positive phase durations, and incident impulses (3): 10 atm, 0.25 ms, and 3.9 psi-ms at the front of the head (14 cm from charge), and 1.4 atm, 0.32 ms, and 1.7 psi-ms at the back of a typical 20 cm head (34 cm from charge). The peak pressure of the wave decreases by a factor of 7 as it traverses the head. The blast conditions are at the threshold for injury at the front of the head, but well below threshold at the back of the head (4). The blast traverses the head in 0.3 ms, roughly equal to the positive phase duration of the blast. Therefore, when the blast reaches the back of the head, near ambient conditions exist at the …
Date: January 21, 2011
Creator: Moss, W C; King, M J & Blackman, E G
System: The UNT Digital Library
Programmable Beam Spatial Shaping System for the National Ignition Facility (open access)

Programmable Beam Spatial Shaping System for the National Ignition Facility

A system of customized spatial light modulators has been installed onto the front end of the laser system at the National Ignition Facility (NIF). The devices are capable of shaping the beam profile at a low-fluence relay plane upstream of the amplifier chain. Their primary function is to introduce 'blocker' obscurations at programmed locations within the beam profile. These obscurations are positioned to shadow small, isolated flaws on downstream optical components that might otherwise limit the system operating energy. The modulators were designed to enable a drop-in retrofit of each of the 48 existing Pre Amplifier Modules (PAMs) without compromising their original performance specifications. This was accomplished by use of transmissive Optically Addressable Light Valves (OALV) based on a Bismuth Silicon Oxide photoconductive layer in series with a twisted nematic liquid crystal (LC) layer. These Programmable Spatial Shaper packages in combination with a flaw inspection system and optic registration strategy have provided a robust approach for extending the operational lifetime of high fluence laser optics on NIF.
Date: January 21, 2011
Creator: Heebner, J.; Borden, M.; Miller, P.; Hunter, S.; Christensen, K.; Scanlan, M. et al.
System: The UNT Digital Library
Proof-of-principle experiment for FEL-based coherent electron cooling (open access)

Proof-of-principle experiment for FEL-based coherent electron cooling

Coherent electron cooling (CEC) has a potential to significantly boost luminosity of high-energy, high-intensity hadron-hadron and electron-hadron colliders. In a CEC system, a hadron beam interacts with a cooling electron beam. A perturbation of the electron density caused by ions is amplified and fed back to the ions to reduce the energy spread and the emittance of the ion beam. To demonstrate the feasibility of CEC we propose a proof-of-principle experiment at RHIC using SRF linac. In this paper, we describe the setup for CeC installed into one of RHIC's interaction regions. We present results of analytical estimates and results of initial simulations of cooling a gold-ion beam at 40 GeV/u energy via CeC. We plan to complete the program in five years. During first two years we will build coherent electron cooler in IP2 of RHIC. In parallel we will develop complete package of computer simulation tools for the start-to-end simulation predicting exact performance of a CeC. The later activity will be the core of Tech X involvement into the project. We will use these tools to predict the performance of our CeC device. The experimental demonstration of the CeC will be undertaken in years three to five of …
Date: August 21, 2011
Creator: Litvinenko, V. N.; Belomestnykh, S.; Ben-Zvi, Ilan; Brutus, J. C.; Fedotov, A.; Hao, Y. et al.
System: The UNT Digital Library
TRITIUM IN-BED ACCOUNTABILITY FOR A PASSIVELY COOLED, ELECTRICALLY HEATED HYDRIDE BED (open access)

TRITIUM IN-BED ACCOUNTABILITY FOR A PASSIVELY COOLED, ELECTRICALLY HEATED HYDRIDE BED

A PAssively Cooled, Electrically heated hydride (PACE) Bed has been deployed into tritium service in the Savannah River Site (SRS) Tritium Facilities. The bed design, absorption and desorption performance, and cold (non-radioactive) in-bed accountability (IBA) results have been reported previously. Six PACE Beds were fitted with instrumentation to perform the steady-state, flowing gas calorimetric inventory method. An IBA inventory calibration curve, flowing gas temperature rise ({Delta}T) versus simulated or actual tritium loading, was generated for each bed. Results for non-radioactive ('cold') tests using the internal electric heaters and tritium calibration results are presented. Changes in vacuum jacket pressure significantly impact measured IBA {Delta}T values. Higher jacket pressures produce lower IBA {Delta}T values which underestimate bed tritium inventories. The exhaust pressure of the IBA gas flow through the bed's U-tube has little influence on measured IBA {Delta}T values, but larger gas flows reduce the time to reach steady-state conditions and produce smaller tritium measurement uncertainties.
Date: January 21, 2011
Creator: Klein, J. & Foster, P.
System: The UNT Digital Library
Simulating the Daylight Performance of Complex Fenestration Systems Using Bidirectional Scattering Distribution Functions within Radiance (open access)

Simulating the Daylight Performance of Complex Fenestration Systems Using Bidirectional Scattering Distribution Functions within Radiance

We describe two methods which rely on bidirectional scattering distribution functions (BSDFs) to model the daylighting performance of complex fenestration systems (CFS), enabling greater flexibility and accuracy in evaluating arbitrary assemblies of glazing, shading, and other optically-complex coplanar window systems. Two tools within Radiance enable a) efficient annual performance evaluations of CFS, and b) accurate renderings of CFS despite the loss of spatial resolution associated with low-resolution BSDF datasets for inhomogeneous systems. Validation, accuracy, and limitations of the methods are discussed.
Date: January 21, 2011
Creator: Ward, Gregory; Mistrick, Ph.D., Richard; Lee, Eleanor; McNeil, Andrew & Jonsson, Ph.D., Jacob
System: The UNT Digital Library
Experiment to Detect Accelerating Modes in a Photonic Bandgap Fiber (open access)

Experiment to Detect Accelerating Modes in a Photonic Bandgap Fiber

An experimental effort is currently underway at the E-163 test beamline at Stanford Linear Accelerator Center to use a hollow-core photonic bandgap (PBG) fiber as a high-gradient laser-based accelerating structure for electron bunches. For the initial stage of this experiment, a 50pC, 60 MeV electron beam will be coupled into the fiber core and the excited modes will be detected using a spectrograph to resolve their frequency signatures in the wakefield radiation generated by the beam. They will describe the experimental plan and recent simulation studies of candidate fibers.
Date: November 21, 2011
Creator: England, R.J.; /SLAC; Colby, E.R.; /SLAC; Ischebeck, R.; /Munich, Max Planck Inst. Quantenopt. et al.
System: The UNT Digital Library
LER control and mitigation: mask roughness induced LER (open access)

LER control and mitigation: mask roughness induced LER

In the push towards commercialization of extreme-ultraviolet lithography (EUVL), meeting the stringent requirements for line-edge roughness (LER) is increasingly challenging. For the 22-nm half-pitch node and below, the ITRS requires under 1.2 nm LER. Much of this LER is thought to arise from three significant contributors: LER on the mask absorber pattern, LER from the resist, and LER from mask roughness induced speckle. The physical mechanism behind the last contributor is becoming clearer, but how it is affected by the presence of aberrations is less well understood. Here, we conduct a full 2D aerial image simulation analysis of aberrations sensitivities of mask roughness induced LER for the first 37 fringe zernikes. These results serve as a guideline for future LER aberrations control. In examining how to mitigate mask roughness induced LER, we next consider an alternate illumination scheme whereby a traditional dipole's angular spectrum is extended in the direction parallel to the line-and-space mask absorber pattern to represent a 'strip'. While this illumination surprisingly provides merely minimal improvement to the LER as several alternate illumination schemes, overall imaging quality in terms of ILS, NILS, and contrast is improved. While the 22-nm half-pitch node can tolerate significant aberrations from a mask …
Date: February 21, 2011
Creator: McClinton, Brittany & Naulleau, Patrick
System: The UNT Digital Library
Quarkonium States at B-Factories (open access)

Quarkonium States at B-Factories

An overview is given on recent progress in the study of quarkonium spectroscopy at the B-factories. In particular, an updated status report is presented of the long list of 'charmonium-like' resonances newly discovered, whose assignment as true charmonium states is in most cases at least controversial. Also, new measurements on the decay properties of bottomonium states above open-B production thresholds are shown. Much of the progress attained in recent years in the study of the quarkonium spectra is owed to the measurements performed at B-factories. The impressive amount of data recorded by the BABAR and Belle experiments has made it possible to study rare decay chains and to look for as yet undiscovered resonances in the charmonium and bottomonium mass regions. Results presented here are based on different subsamples of the full datasets recorded up to now by the two experiments, corresponding to integrated luminosities of about 430 fb{sup -1}(BABAR - final) and about 850 fb{sup -1}(Belle). Significant contributions also come from the analysis of the various data samples recorded by the CLEO detector.
Date: November 21, 2011
Creator: Robutti, Enrico & /INFN, Genoa
System: The UNT Digital Library
Analysis and Mitigation of X-Ray Hazard Generated From High Intensity Laser-Target Interactions (open access)

Analysis and Mitigation of X-Ray Hazard Generated From High Intensity Laser-Target Interactions

Interaction of a high intensity laser with matter may generate an ionizing radiation hazard. Very limited studies have been made, however, on the laser-induced radiation protection issue. This work reviews available literature on the physics and characteristics of laser-induced X-ray hazards. Important aspects include the laser-to-electron energy conversion efficiency, electron angular distribution, electron energy spectrum and effective temperature, and bremsstrahlung production of X-rays in the target. The possible X-ray dose rates for several femtosecond Ti:sapphire laser systems used at SLAC, including the short pulse laser system for the Matter in Extreme Conditions Instrument (peak power 4 TW and peak intensity 2.4 x 10{sup 18} W/cm{sup 2}) were analysed. A graded approach to mitigate the laser-induced X-ray hazard with a combination of engineered and administrative controls is also proposed.
Date: March 21, 2011
Creator: Qiu, R.; Liu, J. C.; Prinz, A. A.; Rokni, S. H.; Woods, M. & Xia, Z.
System: The UNT Digital Library
GPU-based Scalable Volumetric Reconstruction for Multi-view Stereo (open access)

GPU-based Scalable Volumetric Reconstruction for Multi-view Stereo

We present a new scalable volumetric reconstruction algorithm for multi-view stereo using a graphics processing unit (GPU). It is an effectively parallelized GPU algorithm that simultaneously uses a large number of GPU threads, each of which performs voxel carving, in order to integrate depth maps with images from multiple views. Each depth map, triangulated from pair-wise semi-dense correspondences, represents a view-dependent surface of the scene. This algorithm also provides scalability for large-scale scene reconstruction in a high resolution voxel grid by utilizing streaming and parallel computation. The output is a photo-realistic 3D scene model in a volumetric or point-based representation. We demonstrate the effectiveness and the speed of our algorithm with a synthetic scene and real urban/outdoor scenes. Our method can also be integrated with existing multi-view stereo algorithms such as PMVS2 to fill holes or gaps in textureless regions.
Date: September 21, 2011
Creator: Kim, H.; Duchaineau, M. & Max, N.
System: The UNT Digital Library
THERMAL ANALYSIS OF WASTE GLASS MELTER FEEDS (open access)

THERMAL ANALYSIS OF WASTE GLASS MELTER FEEDS

Melter feeds for high-level nuclear waste (HLW) typically contain a large number of constituents that evolve gas on heating, Multiple gas-evolving reactions are both successive and simultaneous, and include the release of chemically bonded water, reactions of nitrates with organics, and reactions of molten salts with solid silica. Consequently, when a sample of a HLW feed is subjected to thermogravimetric analysis (TGA), the rate of change of the sample mass reveals multiple overlapping peaks. In this study, a melter feed, formulated for a simulated high-alumina HLW to be vitrified in the Waste Treatment and Immobilization Plant, currently under construction at the Hanford Site in Washington State, USA, was subjected to TGA. In addition, a modified melter feed was prepared as an all-nitrate version of the baseline feed to test the effect of sucrose addition on the gas-evolving reactions. Activation energies for major reactions were determined using the Kissinger method. The ultimate aim of TGA studies is to obtain a kinetic model of the gas-evolving reactions for use in mathematical modeling of the cold cap as an element of the overall model of the waste-glass melter. In this study, we focused on computing the kinetic parameters of individual reactions without identifying …
Date: October 21, 2011
Creator: Kruger, A. A.; Hrma, Pavel R.; Pokorny, Richard & Pierce, David A.
System: The UNT Digital Library
The Lack of Torus Emission from BL Lacertae Objects: An Infrared View of Unification with WISE (open access)

The Lack of Torus Emission from BL Lacertae Objects: An Infrared View of Unification with WISE

This article uses data from the Wide-Field Infrared Survey Explorer to perform a statistical study on the mid-infrared properties of a large number of BL Lac objects.
Date: December 21, 2011
Creator: Plotkin, Richard M.; Anderson, Scott F.; Brandt, William Nielsen; Markoff, Sera; Shemmer, Ohad & Wu, Jianfeng
System: The UNT Digital Library
Undistorted 3D microstructures in SU8 formed through two-photon polymerization (open access)

Undistorted 3D microstructures in SU8 formed through two-photon polymerization

This article presents the wavelength dependence of two-photon polymerization in SU-8 between 720-780 nm.
Date: September 21, 2011
Creator: Ohlinger, Kris; Lin, Yuankun; Poole, Zsolt & Chen, Kevin P.
System: The UNT Digital Library
Atmospheric Stability Affects Wind Turbine Power Collection (open access)

Atmospheric Stability Affects Wind Turbine Power Collection

None
Date: April 21, 2011
Creator: Wharton, S & Lundquist, J K
System: The UNT Digital Library
Nonequilibrium candidate Monte Carlo: A new tool for equilibrium simulation (open access)

Nonequilibrium candidate Monte Carlo: A new tool for equilibrium simulation

None
Date: June 21, 2011
Creator: Nilmeier, J P; Crooks, G E; Minh, D L & Chodera, J D
System: The UNT Digital Library
Role of Singular Layers in the Plasma Response to Resonant Magnetic Perturbations (open access)

Role of Singular Layers in the Plasma Response to Resonant Magnetic Perturbations

None
Date: October 21, 2011
Creator: Waelbroeck, F L; Joseph, I; Nardon, E; Becoulet, M & Fitzpatrick, R
System: The UNT Digital Library
The r-process in Metal Poor Stars, and Black Hole Formation (open access)

The r-process in Metal Poor Stars, and Black Hole Formation

None
Date: July 21, 2011
Creator: Boyd, R. N.; Famiano, M. A.; Meyer, B. S.; Motizuki, Y.; Kajino, T. & Roederer, I. U.
System: The UNT Digital Library
Optimization of nonlinear optical properties of ZnO micro and nanocrystals for biophotonics (open access)

Optimization of nonlinear optical properties of ZnO micro and nanocrystals for biophotonics

This article investigates the defects in ZnO created during its synthesis and its affect on the second and third-order nonlinear processes.
Date: July 21, 2011
Creator: Urban, Ben E.; Lin, Jie; Kumar, Os; Senthilkumar, Kasilingam; Fujita, Yasuhisa & Neogi, Arup
System: The UNT Digital Library
Single actomyosin motor interactions in skeletal muscle (open access)

Single actomyosin motor interactions in skeletal muscle

This article presents a study of intramuscular motion during contraction of skeletal muscle myofibrils.
Date: February 21, 2011
Creator: Földes-Papp, Zeno; Liao, Jeff Shih-Chu; Barbieri, Ben; Grycznski, Karol G.; Luchowski, Rafal; Gryczynski, Ignacy et al.
System: The UNT Digital Library