Using EnergyPlus to Perform Dehumidification Analysis on Building America Homes: Preprint (open access)

Using EnergyPlus to Perform Dehumidification Analysis on Building America Homes: Preprint

A parametric study was conducted using EnergyPlus version 6.0 to investigate humidity issues on a typical mid-1990s reference home, a 2006 International Energy Conservation Code home, and a high-performance home in a hot-humid climate. The impacts of various dehumidification equipment and controls are analyzed on the high performance home. The study examined the combined effects of infiltration and mechanical ventilation with balanced and unbalanced mechanical ventilation systems. Indoor relative humidity excursions were examined; specifically, the number of excursions, average excursion length, and maximum excursion length. Space relative humidity, thermal comfort, and whole-house source energy consumption were analyzed for indoor relative humidity set points of 50%, 55%, and 60%. The study showed and explained why similar trends of high humidity were observed in all three homes regardless of energy efficiency, and why humidity problems are not necessarily unique in high-performance homes. Thermal comfort analysis indicated that occupants are unlikely to notice indoor humidity problems. The study confirmed that supplemental dehumidification should be provided to maintain space relative humidity below 60% in a hot-humid climate.
Date: March 1, 2011
Creator: Fang, X.; Winkler, J. & Christensen, D.
System: The UNT Digital Library
Soft X-Ray and Vacuum Ultraviolet Based Spectroscopy of the Actinides (open access)

Soft X-Ray and Vacuum Ultraviolet Based Spectroscopy of the Actinides

The subjects of discussion included: VUV photoelectron spectroscopy, X-ray photoelectron spectroscopy, Synchrotron-radiation-based photoelectron spectroscopy, Soft x-ray absorption spectroscopy, Soft x-ray emission spectroscopy, Inverse photoelectron spectroscopy, Bremstrahlung Isochromat Spectroscopy, Low energy IPES, Resonant inverse photoelectron spectroscopy.
Date: March 17, 2011
Creator: Tobin, J. G.
System: The UNT Digital Library
Efficient Graph Based Assembly of Short-Read Sequences on Hybrid Core Architecture (open access)

Efficient Graph Based Assembly of Short-Read Sequences on Hybrid Core Architecture

Advanced architectures can deliver dramatically increased throughput for genomics and proteomics applications, reducing time-to-completion in some cases from days to minutes. One such architecture, hybrid-core computing, marries a traditional x86 environment with a reconfigurable coprocessor, based on field programmable gate array (FPGA) technology. In addition to higher throughput, increased performance can fundamentally improve research quality by allowing more accurate, previously impractical approaches. We will discuss the approach used by Convey?s de Bruijn graph constructor for short-read, de-novo assembly. Bioinformatics applications that have random access patterns to large memory spaces, such as graph-based algorithms, experience memory performance limitations on cache-based x86 servers. Convey?s highly parallel memory subsystem allows application-specific logic to simultaneously access 8192 individual words in memory, significantly increasing effective memory bandwidth over cache-based memory systems. Many algorithms, such as Velvet and other de Bruijn graph based, short-read, de-novo assemblers, can greatly benefit from this type of memory architecture. Furthermore, small data type operations (four nucleotides can be represented in two bits) make more efficient use of logic gates than the data types dictated by conventional programming models.JGI is comparing the performance of Convey?s graph constructor and Velvet on both synthetic and real data. We will present preliminary results on …
Date: March 22, 2011
Creator: Sczyrba, Alex; Pratap, Abhishek; Canon, Shane; Han, James; Copeland, Alex; Wang, Zhong et al.
System: The UNT Digital Library
Amplification of current density modulation in a FEL with an infinite electron beam (open access)

Amplification of current density modulation in a FEL with an infinite electron beam

We show that the paraxial field equation for a free electron laser (FEL) in an infinitely wide electron beam with {kappa}-2 energy distribution can be reduced to a fourth ordinary differential equation (ODE). Its solution for arbitrary initial phase space density modulation has been derived in the wave-vector domain. For initial current modulation with Gaussian profile, close form solutions are obtained in space-time domain. In developing an analytical model for a FEL-based coherent electron cooling system, an infinite electron beam has been assumed for the modulation and correction processes. While the assumption has its limitation, it allows for an analytical close form solution to be obtained, which is essential for investigating the underlying scaling law, benchmarking the simulation codes and understanding the fundamental physics. 1D theory was previously applied to model a CeC FEL amplifier. However, the theory ignores diffraction effects and does not provide the transverse profile of the amplified electron density modulation. On the other hand, 3D theories developed for a finite electron beam usually have solutions expanded over infinite number of modes determined by the specific transverse boundary conditions. Unless the mode with the largest growth rate substantially dominates other modes, both evaluation and extracting scaling laws …
Date: March 28, 2011
Creator: Wang, G.; Litvinenko, V. N. & Webb, S. D.
System: The UNT Digital Library
Computational Hydrocode Study of Target Damage due to Fragment-Blast Impact (open access)

Computational Hydrocode Study of Target Damage due to Fragment-Blast Impact

A target's terminal ballistic effects involving explosively generated fragments, along with the original blast, are of critical importance for many different security and safety related applications. Personnel safety and protective building design are but a few of the practical disciplines that can gain from improved understanding combined loading effects. Traditionally, any engineering level analysis or design effort involving explosions would divide the target damage analysis into two correspondingly critical areas: blast wave and fragment related impact effects. The hypothesis of this paper lies in the supposition that a linear combination of a blast-fragment loading, coupled with an accurate target response description, can lead to a non-linear target damage effect. This non-linear target response could then stand as the basis of defining what a synergistic or combined frag-blast loading might actually look like. The table below, taken from Walters, et. al. categorizes some of the critical parameters driving any combined target damage effect and drives the evaluation of results. Based on table 1 it becomes clear that any combined frag-blast analysis would need to account for the target response matching similar ranges for the mechanics described above. Of interest are the critical times upon which a blast event or fragment impact …
Date: March 24, 2011
Creator: Hatch-Aguilar, T; Najjar, F & Szymanski, E
System: The UNT Digital Library
Baseline suppression problems for high precision measurements using optical beam profile monitors (open access)

Baseline suppression problems for high precision measurements using optical beam profile monitors

The use of fluorescent screens (e.g. YAG screens) and Optical Transition Radiation (OTR) screens for beam profile monitors provides a simple and widely used way to obtain detailed two dimensional intensity maps. What makes this possible is the availability of relatively inexpensive CCD cameras. For high precision measurements many possible error contributions need to be considered that have to do with properties of the fluorescent screens and of the CCDs. Saturation effects, reflections within and outside the screen, non-linearities, radiation damage, etc are often mentioned. Here we concentrate on an error source less commonly described, namely erroneous baseline subtraction, which is particularly important when fitting projected images. We show computer simulations as well as measurement results having remarkable sensitivity of the fitted profile widths to even partial suppression of the profile baseline data, which often arises from large pixel-to-pixel variations at low intensity levels. Such inadvertent baseline data suppression is very easy to miss as it is usually not obvious when inspecting projected profiles. In this report we illustrate this effect and discuss possible algorithms to automate the detection of this problem as well as some possible corrective measures.
Date: March 28, 2011
Creator: Thieberger, P.; Gassner, D.; Glenn, J.; Minty, M. & Zimmer, C.
System: The UNT Digital Library
Beam losses due to abrupt crab cavity failures in the LHC (open access)

Beam losses due to abrupt crab cavity failures in the LHC

A major concern for the implementation of crab crossing in a future High-Luminosity LHC (HL-LHC) is machine protection in an event of a fast crab-cavity failure. Certain types of abrupt crab-cavity amplitude and phase changes are simulated to characterize the effect of failures on the beam and the resulting particle-loss signatures. The time-dependent beam loss distributions around the ring and particle trajectories obtained from the simulations allow for a first assessment of the resulting beam impact on LHC collimators and on sensitive components around the ring. Results for the nominal LHC lattice is presented.
Date: March 28, 2011
Creator: Baer, T.; Barranco, J.; Calaga, R.; Tomas, R.; Wenninger, B.; Yee, B. et al.
System: The UNT Digital Library
Nonlinear pulse propagation and phase velocity of laser-driven plasma waves (open access)

Nonlinear pulse propagation and phase velocity of laser-driven plasma waves

Laser evolution and plasma wave excitation by a relativistically-intense short-pulse laser in underdense plasma are investigated in the broad pulse limit, including the effects of pulse steepening, frequency red-shifting, and energy depletion. The nonlinear plasma wave phase velocity is shown to be significantly lower than the laser group velocity and further decreases as the pulse propagates owing to laser evolution. This lowers the thresholds for trapping and wavebreaking, and reduces the energy gain and efficiency of laser-plasma accelerators that use a uniform plasma profile.
Date: March 25, 2011
Creator: Schroeder, Carl B.; Benedetti, Carlo; Esarey, Eric & Leemans, Wim
System: The UNT Digital Library
New HOM coupler design for high current SRF cavity (open access)

New HOM coupler design for high current SRF cavity

Damping higher order modes (HOMs) significantly to avoid beam instability is a challenge for the high current Energy Recovery Linac-based eRHIC at BNL. To avoid the overheating effect and high tuning sensitivity, current, a new band-stop HOM coupler is being designed at BNL. The new HOM coupler has a bandwidth of tens of MHz to reject the fundamental mode, which will avoid overheating due to fundamental frequency shifting because of cooling down. In addition, the S21 parameter of the band-pass filter is nearly flat from first higher order mode to 5 times the fundamental frequency. The simulation results showed that the new couplers effectively damp HOMs for the eRHIC cavity with enlarged beam tube diameter and 2 120{sup o} HOM couplers at each side of cavity. This paper presents the design of HOM coupler, HOM damping capacity for eRHIC cavity and prototype test results.
Date: March 28, 2011
Creator: Xu, W.; Ben-Zvi, Ilan; Belomestnykh, S.; Hahn, H. & Johnson, E.
System: The UNT Digital Library
STUDY ON AIR INGRESS MITIGATION METHODS IN THE VERY HIGH TEMPERATURE GAS COOLED REACTOR (VHTR) (open access)

STUDY ON AIR INGRESS MITIGATION METHODS IN THE VERY HIGH TEMPERATURE GAS COOLED REACTOR (VHTR)

An air-ingress accident followed by a pipe break is considered as a critical event for a very high temperature gas-cooled reactor (VHTR). Following helium depressurization, it is anticipated that unless countermeasures are taken, air will enter the core through the break leading to oxidation of the in-core graphite structure. Thus, without mitigation features, this accident might lead to severe exothermic chemical reactions of graphite and oxygen. Under extreme circumstances, a loss of core structural integrity may occur along with excessive release of radiological inventory. Idaho National Laboratory under the auspices of the U.S. Department of Energy is performing research and development (R&D) that focuses on key phenomena important during challenging scenarios that may occur in the VHTR. Phenomena Identification and Ranking Table (PIRT) studies to date have identified the air ingress event, following on the heels of a VHTR depressurization, as very important (Oh et al. 2006, Schultz et al. 2006). Consequently, the development of advanced air ingress-related models and verification and validation (V&V) requirements are part of the experimental validation plan. This paper discusses about various air-ingress mitigation concepts applicable for the VHTRs. The study begins with identifying important factors (or phenomena) associated with the air-ingress accident by using …
Date: March 1, 2011
Creator: Oh, Chang H.
System: The UNT Digital Library
Energy Use Intensity and its Influence on the Integrated Daylighting Design of a Large Net Zero Energy Building: Preprint (open access)

Energy Use Intensity and its Influence on the Integrated Daylighting Design of a Large Net Zero Energy Building: Preprint

Net-zero energy buildings generate as much energy as they consume and are significant in the sustainable future of building design and construction. The role of daylighting (and its simulation) in the design process becomes critical. In this paper we present the process the National Renewable Energy Laboratory embarked on in the procurement, design, and construction of its newest building, the Research Support Facility (RSF) - particularly the roles of daylighting, electric lighting, and simulation. With a rapid construction schedule, the procurement, design, and construction had to be tightly integrated; with low energy use. We outline the process and measures required to manage a building design that could expect to operate at an efficiency previously unheard of for a building of this type, size, and density. Rigorous simulation of the daylighting and the electric lighting control response was a given, but the oft-ignored disconnect between lighting simulation and whole-building energy use simulation had to be addressed. The RSF project will be thoroughly evaluated for its performance for one year; preliminary data from the postoccupancy monitoring efforts will also be presented with an eye toward the current efficacy of building energy and lighting simulation.
Date: March 1, 2011
Creator: Guglielmetti , R.; Scheib, J.; Pless, S. D.; Torcellini , P. & Petro, R.
System: The UNT Digital Library
DESIGN AND PRELIMINARY TEST OF THE 1500 MHZ NSLS-II PASSIVE SUPERCONDUCTING RF CAVITY (open access)

DESIGN AND PRELIMINARY TEST OF THE 1500 MHZ NSLS-II PASSIVE SUPERCONDUCTING RF CAVITY

NSLS-II is a new ultra-bright 3 GeV 3rd generation synchrotron radiation light source. The performance goals require operation with a beam current of 500mA and a bunch current of at least 0.5mA. Ion clearing gaps are required to suppress ion effects on the beam. The natural bunch length of 3mm is planned to be lengthened by means of a third harmonic cavity in order to increase the Touschek limited lifetime. Earlier work described the design alternatives and the geometry selected for a copper prototype. We subsequently have iterated the design to lower the R/Q of the cavity and to increase the diameter of the beam pipe ferrite HOM dampers to reduce the wakefield heating. A niobium cavity and full cryomodule including LN2 shield, magnetic shield and insulating vacuum vessel have been fabricated and installed. A passive SRF 3rd harmonic cavity consisting of two tightly coupled cells has been designed and fabricated for NSLS-II. Initial cold tests of this cavity are very promising. These tests have verified that the cavity frequency and mode separation between the 0 and {pi}-modes can be set at manufacture. Further, the frequency separation can be maintained over wide tuning ranges necessary for operation. Future work includes …
Date: March 28, 2011
Creator: Rose, J.; Gash, W.; Kosciuk, B.; Ravindranath, V.; Sikora, B.; Sharma, S. et al.
System: The UNT Digital Library
Charge Separation for Muon Collider Cooling (open access)

Charge Separation for Muon Collider Cooling

Most schemes for six dimensional muon ionization cooling work for only one sign. It is then necessary to have charge separation prior to that cooling. Schemes of charge separation using bent solenoids are described, and their simulated performances reported. It is found that for efficient separation, it should take place at somewhat higher momenta than commonly used for the cooling. Charge separation using bent solenoids can be effective if carefully designed. Bent solenoids can generate dispersion from 'momentum drift', but can spoil emittance from 'amplitude drift'. Abrupt entry into a bent solenoid causes emittance growth, but matching using integral {lambda} lengths, or Norem's method, corrects this problem. Reverse bending removes the dispersion and reduces 'amplitude drift', but only if there is no rf until after all bending. The main problem is bunch lengthening and distortion from the long transports without rf. At 230 MeV/c, even with a higher field of 3 T, non-linearities increase the 6D emittance by 117% and give 13% loss, which is not acceptable. Raising the momentum from 230 to 300 MeV gives a 6D emittance growth of 38% and the loss 5%, which may be acceptable. Raising the momentum further to 400 MeV/c gives very good …
Date: March 28, 2011
Creator: Palmer, R. B.
System: The UNT Digital Library
Autonomous Sub-Pixel Satellite Track Endpoint Determination for Space Based Images (open access)

Autonomous Sub-Pixel Satellite Track Endpoint Determination for Space Based Images

An algorithm for determining satellite track endpoints with sub-pixel resolution in spaced-based images is presented. The algorithm allows for significant curvature in the imaged track due to rotation of the spacecraft capturing the image. The motivation behind the subpixel endpoint determination is first presented, followed by a description of the methodology used. Results from running the algorithm on real ground-based and simulated spaced-based images are shown to highlight its effectiveness.
Date: March 7, 2011
Creator: Simms, L M
System: The UNT Digital Library
Dipole corrector magnets for the LBNE beam line (open access)

Dipole corrector magnets for the LBNE beam line

The conceptual design of a new dipole corrector magnet has been thoroughly studied. The planned Long-Baseline Neutrino Experiment (LBNE) beam line will require correctors capable of greater range and linearity than existing correctors, so a new design is proposed based on the horizontal trim dipole correctors built for the Main Injector synchrotron at Fermilab. The gap, pole shape, length, and number of conductor turns remain the same. To allow operation over a wider range of excitations without overheating, the conductor size is increased, and to maintain better linearity, the back leg thickness is increased. The magnetic simulation was done using ANSYS to optimize the shape and the size of the yoke. The thermal performance was also modeled and analyzed.
Date: March 1, 2011
Creator: Yu, M.; Velev, G.; Harding, D. & /Fermilab
System: The UNT Digital Library
Performance of the new EBIS preinjector (open access)

Performance of the new EBIS preinjector

The construction and initial commissioning phase of a new heavy ion preinjector was completed at Brookhaven in September, 2010, and the preinjector is now operational. This preinjector, using an EBIS source to produce high charge state heavy ions, provided helium and neon ion beams for use at the NASA Space Radiation Laboratory in the Fall of 2010, and gold and uranium beams are being commissioned during the 2011 run cycle for use in RHIC. The EBIS operates with an electron beam current of up to 10 A, to produce mA level currents in 10-40 {micro}s beam pulses. The source is followed by an RFQ and IH linac to accelerate ions with q/m > 0.16 to an energy of 2 MeV/amu, for injection into the Booster synchrotron. The performance of the preinjector is presented, including initial operational experience for the NASA and RHIC programs.
Date: March 28, 2011
Creator: Alessi, J.; Beebe, E.; Binello, S.; Gardner, C.; Gould, O.; Hoff, L. et al.
System: The UNT Digital Library
Unraveling the nature of charge excitations in La2CuO4 with momentum-resolved Cu K-edge resonant inelastic X-ray scattering (open access)

Unraveling the nature of charge excitations in La2CuO4 with momentum-resolved Cu K-edge resonant inelastic X-ray scattering

Results of model calculations using exact diagonalization reveal the orbital character of states associated with different Raman loss peaks in Cu K-edge resonant inelastic X-ray scattering (RIXS) from La{sub 2}CuO{sub 4}. The model includes electronic orbitals necessary to highlight non-local Zhang-Rice singlet, charge transfer and d-d excitations, as well as states with apical oxygen 2p{sub z} character. The dispersion of these excitations is discussed with prospects for resonant final state wave-function mapping. A good agreement with experiments emphasizes the substantial multi-orbital character of RIXS profiles in the energy transfer range 1-6 eV.
Date: March 1, 2011
Creator: Chen, Cheng-Chien
System: The UNT Digital Library
The dipole corrector magnets for the RHIC fast global orbit feedback system (open access)

The dipole corrector magnets for the RHIC fast global orbit feedback system

The recently completed RHIC fast global orbit feedback system uses 24 small 'window-frame' horizontal dipole correctors. Space limitations dictated a very compact design. The magnetic design and modelling of these laminated yoke magnets is described as well as the mechanical implementation, coil winding, vacuum impregnation, etc. Test procedures to determine the field quality and frequency response are described. The results of these measurements are presented and discussed. A small fringe field from each magnet, overlapping the opposite RHIC ring, is compensated by a correction winding placed on the opposite ring's magnet and connected in series with the main winding of the first one. Results from measurements of this compensation scheme are shown and discussed.
Date: March 28, 2011
Creator: Thieberger, P.; Arnold, L.; Folz, C.; Hulsart, R.; Jain, A.; Karl, R. et al.
System: The UNT Digital Library
First high power pulsed tests of a dressed 325 MHz superconducting single spoke resonator at Fermilab (open access)

First high power pulsed tests of a dressed 325 MHz superconducting single spoke resonator at Fermilab

In the recently commissioned superconducting RF cavity test facility at Fermilab (SCTF), a 325 MHz, {beta} = 0.22 superconducting single-spoke resonator (SSR1) has been tested for the first time with its input power coupler. Previously, this cavity had been tested CW with a low power, high Q{sub ext} test coupler; first as a bare cavity in the Fermilab Vertical Test Stand and then fully dressed in the SCTF. For the tests described here, the design input coupler with Q{sub ext} {approx} 10{sup 6} was used. Pulsed power was provided by a Toshiba E3740A 2.5 MW klystron.
Date: March 1, 2011
Creator: Madrak, R.; Branlard, J.; Chase, B.; Darve, C.; Joireman, P.; Khabiboulline, T. et al.
System: The UNT Digital Library
SCALE ANALYSIS OF CONVECTIVE MELTING WITH INTERNAL HEAT GENERATION (open access)

SCALE ANALYSIS OF CONVECTIVE MELTING WITH INTERNAL HEAT GENERATION

Using a scale analysis approach, we model phase change (melting) for pure materials which generate internal heat for small Stefan numbers (approximately one). The analysis considers conduction in the solid phase and natural convection, driven by internal heat generation, in the liquid regime. The model is applied for a constant surface temperature boundary condition where the melting temperature is greater than the surface temperature in a cylindrical geometry. We show the time scales in which conduction and convection heat transfer dominate.
Date: March 1, 2011
Creator: Crepeau, John
System: The UNT Digital Library
Establishment of Small Wind Regional Test Centers: Preprint (open access)

Establishment of Small Wind Regional Test Centers: Preprint

The rapid growth of the small wind turbine (SWT) market is attracting numerous entrants. Small wind turbine purchasers now have many options but often lack information (such as third-party certification) to select a quality turbine. Most SWTs do not have third-party certification due to the expense and difficulty of the certification process. Until recently, the only SWT certification bodies were in Europe. In North America, testing has been limited to a small number of U.S. Department of Energy (DOE) subsidized tests conducted at the National Wind Technology Center (NWTC) under the ongoing Independent Testing Project. Within the past few years, the DOE, National Renewable Energy Lab (NREL), and some states have worked with the North American SWT industry to create a SWT certification infrastructure. The goal is to increase the number of certified turbines and gain greater consumer confidence in SWT technology. The American Wind Energy Association (AWEA) released the AWEA Small Wind Turbine Performance and Safety Standard (AWEA Standard 9.1 - 2009) in December 2009. The Small Wind Certification Council (SWCC), a North American certification body, began accepting applications for certification to the AWEA standard in February 2010. To reduce certification testing costs, DOE/NREL is providing financial and technical …
Date: March 1, 2011
Creator: Jimenez, T.; Forsyth, T.; Huskey, A.; Mendoza, I.; Sinclair, K. & Smith, J.
System: The UNT Digital Library
RADIOACTIVE MATERIAL PACKAGING TORQUE REQUIREMENTS COMPLIANCE (open access)

RADIOACTIVE MATERIAL PACKAGING TORQUE REQUIREMENTS COMPLIANCE

Shipping containers used to transport radioactive material (RAM) in commerce employ a variety of closure mechanisms. Often, these closure mechanisms require a specific amount of torque be applied to a bolt, nut or other threaded fastener. It is important that the required preload is achieved so that the package testing and analysis is not invalidated for the purpose of protecting the public. Torque compliance is a means of ensuring closure preload, is a major factor in accomplishing the package functions of confinement/containment, sub-criticality, and shielding. This paper will address the importance of applying proper torque to package closures, discuss torque value nomenclature, and present one methodology to ensure torque compliance is achieved.
Date: March 24, 2011
Creator: Watkins, R. & Leduc, D.
System: The UNT Digital Library
Illumina Unamplified Indexed Library Construction: An Automated Approach (open access)

Illumina Unamplified Indexed Library Construction: An Automated Approach

Manual library construction is a limiting factor in Illumina sequencing. Constructing libraries by hand is costly, time-consuming, low-throughput, and ergonomically hazardous, and constructing multiple libraries introduces risk of library failure due to pipetting errors. The ability to construct multiple libraries simultaneously in automated fashion represents significant cost and time savings. Here we present a strategy to construct up to 96 unamplified indexed libraries using Illumina TruSeq reagents and a Biomek FX robotic platform. We also present data to indicate that this library construction method has little or no risk of cross-contamination between samples.
Date: March 21, 2011
Creator: Hack, Christopher A.; Sczyrba, Alexander & Cheng, Jan-Fang
System: The UNT Digital Library
Wedge absorber design and simulation for MICE Step IV (open access)

Wedge absorber design and simulation for MICE Step IV

In the Muon Ionization Cooling Experiment (MICE), muons are cooled by passing through material, then through RF cavities to compensate for the energy loss; which reduces the transverse emittance. It is planned to demonstrate longitudinal emittance reduction via emittance exchange in MICE by using a solid wedge absorber in Step IV. Based on the outcome of previous studies, the shape and material of the wedge were chosen. We address here further simulation efforts for the absorber of choice as well as engineering considerations in connection with the absorber support design.
Date: March 1, 2011
Creator: Rogers, C. T.; Snopok, P.; Coney, L. & Hanson, G.
System: The UNT Digital Library