Echo-seeding options for LCLS-II (open access)

Echo-seeding options for LCLS-II

The success of LCLS has opened up a new era of x-ray sciences. An upgrade to LCLS is currently being planned to enhance its capabilities. In this paper we study the feasibility of using the echo-enabled harmonic generation (EEHG) technique to generate narrow bandwidth soft x-ray radiation in the proposed LCLS-II soft x-ray beam line. We focus on the conceptual design, the technical implementation and the expected performances of the echo-seeding scheme. We will also show how the echo-seeding scheme allows one to generate two color x-ray pulses with the higher energy photons leading the lower energy ones as is favored in the x-ray pump-probe experiments.
Date: September 14, 2010
Creator: Xiang, Dao
Object Type: Article
System: The UNT Digital Library
CMS centres worldwide: A new collaborative infrastructure (open access)

CMS centres worldwide: A new collaborative infrastructure

The CMS Experiment at the LHC is establishing a global network of inter-connected 'CMS Centres' for controls, operations and monitoring. These support: (1) CMS data quality monitoring, detector calibrations, and analysis; and (2) computing operations for the processing, storage and distribution of CMS data. We describe the infrastructure, computing, software, and communications systems required to create an effective and affordable CMS Centre. We present our highly successful operations experiences with the major CMS Centres at CERN, Fermilab, and DESY during the LHC first beam data-taking and cosmic ray commissioning work. The status of the various centres already operating or under construction in Asia, Europe, Russia, South America, and the USA is also described. We emphasise the collaborative communications aspects. For example, virtual co-location of experts in CMS Centres Worldwide is achieved using high-quality permanently-running 'telepresence' video links. Generic Web-based tools have been developed and deployed for monitoring, control, display management and outreach.
Date: January 1, 2010
Creator: Taylor, Lucas & Gottschalk, Erik
Object Type: Article
System: The UNT Digital Library
Initial inclusion of thermodynamic considerations in Kayenta. (open access)

Initial inclusion of thermodynamic considerations in Kayenta.

A persistent challenge in simulating damage of natural geological materials, as well as rock-like engineered materials, is the development of efficient and accurate constitutive models. The common feature for these brittle and quasi-brittle materials are the presence of flaws such as porosity and network of microcracks. The desired models need to be able to predict the material responses over a wide range of porosities and strain rate. Kayenta (formerly called the Sandia GeoModel) is a unified general-purpose constitutive model that strikes a balance between first-principles micromechanics and phenomenological or semi-empirical modeling strategies. However, despite its sophistication and ability to reduce to several classical plasticity theories, Kayenta is incapable of modeling deformation of ductile materials in which deformation is dominated by dislocation generation and movement which can lead to significant heating. This stems from Kayenta's roots as a geological model, where heating due to inelastic deformation is often neglected or presumed to be incorporated implicitly through the elastic moduli. The sophistication of Kayenta and its large set of extensive features, however, make Kayenta an attractive candidate model to which thermal effects can be added. This report outlines the initial work in doing just that, extending the capabilities of Kayenta to include …
Date: July 1, 2010
Creator: Brannon, Rebecca Moss (University of Utah, Salt Lake City, UT); Bishop, Joseph E.; Fuller, Timothy J. (University of Utah, Salt Lake City, UT) & Strack, Otto Eric
Object Type: Report
System: The UNT Digital Library
RAPID SEPARATION METHOD FOR 237NP AND PU ISOTOPES IN LARGE SOIL SAMPLES (open access)

RAPID SEPARATION METHOD FOR 237NP AND PU ISOTOPES IN LARGE SOIL SAMPLES

A new rapid method for the determination of {sup 237}Np and Pu isotopes in soil and sediment samples has been developed at the Savannah River Site Environmental Lab (Aiken, SC, USA) that can be used for large soil samples. The new soil method utilizes an acid leaching method, iron/titanium hydroxide precipitation, a lanthanum fluoride soil matrix removal step, and a rapid column separation process with TEVA Resin. The large soil matrix is removed easily and rapidly using this two simple precipitations with high chemical recoveries and effective removal of interferences. Vacuum box technology and rapid flow rates are used to reduce analytical time.
Date: July 26, 2010
Creator: Maxwell, S.; Culligan, B. & Noyes, G.
Object Type: Article
System: The UNT Digital Library
An implementation of co-simulation for performance prediction of innovative integrated HVAC systems in buildings (open access)

An implementation of co-simulation for performance prediction of innovative integrated HVAC systems in buildings

Integrated performance simulation of buildings and heating, ventilation and air-conditioning (HVAC) systems can help reducing energy consumption and increasing level of occupant comfort. However, no singe building performance simulation (BPS) tool offers sufficient capabilities and flexibilities to accommodate the ever-increasing complexity and rapid innovations in building and system technologies. One way to alleviate this problem is to use co-simulation. The co-simulation approach represents a particular case of simulation scenario where at least two simulators solve coupled differential-algebraic systems of equations and exchange data that couples these equations during the time integration. This paper elaborates on issues important for co-simulation realization and discusses multiple possibilities to justify the particular approach implemented in a co-simulation prototype. The prototype is verified and validated against the results obtained from the traditional simulation approach. It is further used in a case study for the proof-of-concept, to demonstrate the applicability of the method and to highlight its benefits. Stability and accuracy of different coupling strategies are analyzed to give a guideline for the required coupling frequency. The paper concludes by defining requirements and recommendations for generic cosimulation implementations.
Date: July 1, 2010
Creator: Trcka, Marija; Wetter, Michael & Hensen, Jan L. M.
Object Type: Article
System: The UNT Digital Library
Evidence for an anomalous like-sign dimuon charge asymmetry (open access)

Evidence for an anomalous like-sign dimuon charge asymmetry

None
Date: July 1, 2010
Creator: Abazov, Victor Mukhamedovich; Abbott, Braden Keim; Abolins, Maris A.; Acharya, Bannanje Sripath; Adams, Mark Raymond; Adams, Todd et al.
Object Type: Article
System: The UNT Digital Library
Modeling the U.S. Rooftop Photovoltaics Market (open access)

Modeling the U.S. Rooftop Photovoltaics Market

Global rooftop PV markets are growing rapidly, fueled by a combination of declining PV prices and several policy-based incentives. The future growth, and size, of the rooftop market is highly dependent on continued PV cost reductions, financing options, net metering policy, carbon prices and future incentives. Several PV market penetration models, sharing a similar structure and methodology, have been developed over the last decade to quantify the impacts of these factors on market growth. This study uses a geospatially rich, bottom-up, PV market penetration model--the Solar Deployment Systems (SolarDS) model developed by the National Renewable Energy Laboratory--to explore key market and policy-based drivers for residential and commercial rooftop PV markets. The identified drivers include a range of options from traditional incentives, to attractive customer financing options, to net metering and carbon policy.
Date: September 1, 2010
Creator: Drury, E.; Denholm, P. & Margolis, R.
Object Type: Article
System: The UNT Digital Library
Final Work Plan : Phase II Investigation of Potential Contamination at the Former CCC/USDA Grain Storage Facility in Savannah, Missouri. (open access)

Final Work Plan : Phase II Investigation of Potential Contamination at the Former CCC/USDA Grain Storage Facility in Savannah, Missouri.

From approximately 1949 until 1970, the Commodity Credit Corporation of the U.S. Department of Agriculture (CCC/USDA) operated a grain storage facility on federally owned property approximately 0.25 mi northwest of Savannah, Missouri (Figure 1.1). During this time, commercial grain fumigants containing carbon tetrachloride were commonly used by the CCC/USDA and the private grain storage industry to preserve grain in their facilities. In November 1998, carbon tetrachloride was detected in a private well (Morgan) roughly 50 ft south of the former CCC/USDA facility, as a result of statewide screening of private wells near former CCC/USDA facilities, conducted in Missouri by the U.S. Environmental Protection Agency (EPA 1999). The 1998 and subsequent investigations by the EPA and the Missouri Department of Natural Resources (MoDNR) confirmed the presence of carbon tetrachloride in the Morgan well, as well as in a second well (on property currently occupied by the Missouri Department of Transportation [MoDOT]) described as being approximately 400 ft east of the former CCC/USDA facility. The identified concentrations in these two wells were above the EPA maximum contaminant level (MCL) and the Missouri risk-based corrective action default target level (MRBCA DTL) values of 5.0 {micro}g/L for carbon tetrachloride in water used for domestic …
Date: August 16, 2010
Creator: LaFreniere, L. M. & Division, Environmental Science
Object Type: Report
System: The UNT Digital Library
Compressive behavior of fine sand. (open access)

Compressive behavior of fine sand.

The compressive mechanical response of fine sand is experimentally investigated. The strain rate, initial density, stress state, and moisture level are systematically varied. A Kolsky bar was modified to obtain uniaxial and triaxial compressive response at high strain rates. A controlled loading pulse allows the specimen to acquire stress equilibrium and constant strain-rates. The results show that the compressive response of the fine sand is not sensitive to strain rate under the loading conditions in this study, but significantly dependent on the moisture content, initial density and lateral confinement. Partially saturated sand is more compliant than dry sand. Similar trends were reported in the quasi-static regime for experiments conducted at comparable specimen conditions. The sand becomes stiffer as initial density and/or confinement pressure increases. The sand particle size become smaller after hydrostatic pressure and further smaller after dynamic axial loading.
Date: April 1, 2010
Creator: Martin, Bradley E. (Air Force Research Laboratory, Eglin, FL); Kabir, Md. E. (Purdue University, West Lafayette, IN); Song, Bo & Chen, Wayne (Purdue University, West Lafayette, IN)
Object Type: Report
System: The UNT Digital Library
Enhancing FEL Power with Phase Shifters (open access)

Enhancing FEL Power with Phase Shifters

Tapering the undulator parameter is a well-known method for maintaining the resonant condition past saturation, and increasing Free Electron Laser (FEL) efficiency. In this paper, we demonstrate that shifting the electron bunch phase relative to the radiation is equivalent to tapering the undulator parameter. Using discrete phase changes derived from optimized undulator tapers for the Linac Coherent Light Source (LCLS) x-ray FEL, we show that appropriate phase shifts between undulator sections can reproduce the power enhancement of undulator tapers. Phase shifters are relatively easy to implement and operate, and could be used to aid or replace undulator tapers in optimizing FEL performance.
Date: July 30, 2010
Creator: Ratner, Daniel; Chao, Alex & Huang, Zhirong
Object Type: Article
System: The UNT Digital Library
Bacillus anthracis genome organization in light of whole transcriptome sequencing (open access)

Bacillus anthracis genome organization in light of whole transcriptome sequencing

Emerging knowledge of whole prokaryotic transcriptomes could validate a number of theoretical concepts introduced in the early days of genomics. What are the rules connecting gene expression levels with sequence determinants such as quantitative scores of promoters and terminators? Are translation efficiency measures, e.g. codon adaptation index and RBS score related to gene expression? We used the whole transcriptome shotgun sequencing of a bacterial pathogen Bacillus anthracis to assess correlation of gene expression level with promoter, terminator and RBS scores, codon adaptation index, as well as with a new measure of gene translational efficiency, average translation speed. We compared computational predictions of operon topologies with the transcript borders inferred from RNA-Seq reads. Transcriptome mapping may also improve existing gene annotation. Upon assessment of accuracy of current annotation of protein-coding genes in the B. anthracis genome we have shown that the transcriptome data indicate existence of more than a hundred genes missing in the annotation though predicted by an ab initio gene finder. Interestingly, we observed that many pseudogenes possess not only a sequence with detectable coding potential but also promoters that maintain transcriptional activity.
Date: March 22, 2010
Creator: Martin, Jeffrey; Zhu, Wenhan; Passalacqua, Karla D.; Bergman, Nicholas & Borodovsky, Mark
Object Type: Article
System: The UNT Digital Library
Scalability and interoperability within glideinWMS (open access)

Scalability and interoperability within glideinWMS

Physicists have access to thousands of CPUs in grid federations such as OSG and EGEE. With the start-up of the LHC, it is essential for individuals or groups of users to wrap together available resources from multiple sites across multiple grids under a higher user-controlled layer in order to provide a homogeneous pool of available resources. One such system is glideinWMS, which is based on the Condor batch system. A general discussion of glideinWMS can be found elsewhere. Here, we focus on recent advances in extending its reach: scalability and integration of heterogeneous compute elements. We demonstrate that the new developments exceed the design goal of over 10,000 simultaneous running jobs under a single Condor schedd, using strong security protocols across global networks, and sustaining a steady-state job completion rate of a few Hz. We also show interoperability across heterogeneous computing elements achieved using client-side methods. We discuss this technique and the challenges in direct access to NorduGrid and CREAM compute elements, in addition to Globus based systems.
Date: January 1, 2010
Creator: Bradley, D.; Sfiligoi, I.; Padhi, S.; Frey, J. & Tannenbaum, T.
Object Type: Article
System: The UNT Digital Library
beam loss scenarios for MuCool Test Area (open access)

beam loss scenarios for MuCool Test Area

The MuCool Test Area (MTA) is an intense primary beam facility derived directly from the Fermilab Linac to test heat deposition and other technical concerns associated with the liquid hydrogen targets, gas-filled RF cavities, and other apparatus being developed to cool intense, large-emittance muon beams. In this study the results of Monte Carlo modeling of several beam loss scenarios are presented. The MTA facility was designed to test targets and other muon cooling apparatus using the intense Fermilab Linac beam. The requested intensity of the proton beam for the MTA is essentially full Linac capability, or 1.6 x 10{sup 13} protons per pulse and an energy of 400 MeV. Two modes of operation will be supported in the MuCOOL beamline: one mode for emittance measurements (and beamline studies) and a second mode for MTA experiments. Maximum beam intensity for these two modes is: 9.6 x 10{sup 15} protons/hr - 600 beam pulses/hour of full Linac beam pulse intensity (1.6 x 10{sup 13} protons/pulse) to the emittance beam absorber and 9.6 x 10{sup 14} protons/hour - 60 beam pulses/hour of full Linac beam pulse intensity to experiments in the MTA experimental hall. This extremely high intensity implies careful investigation into and …
Date: August 1, 2010
Creator: Rakhno, Igor & Johnstone, Carol
Object Type: Report
System: The UNT Digital Library
Two-Chicane Compressed Harmonic Generation of Soft X-Rays (open access)

Two-Chicane Compressed Harmonic Generation of Soft X-Rays

We propose a simple single-stage scheme to produce fully coherent 3nm radiation. Seeding an electron bunch prior to compression simultaneously shortens the laser wavelength and duration, and increases the modulation amplitude. The final X-ray wavelength is tunable by controlling the compression factor with the RF phase. We propose a two chicane scheme that allows for nearly arbitrary modulation amplitudes, extending the method to photocathode beams. We also show that transportation of fine compressed modulation structure is feasible due to a canceling effect of the second chicane.
Date: July 30, 2010
Creator: Ratner, Daniel; Huang, Z. & Chao, A.
Object Type: Article
System: The UNT Digital Library
Design, Installation, and Initial Commissioning of the MTA Beamline (open access)

Design, Installation, and Initial Commissioning of the MTA Beamline

A new experimental area designed to develop, test and verify muon ionization cooling apparatus using the 400-MeV Fermilab Linac proton beam has been fully installed and is presently being commissioned. Initially, this area was used for cryogenic tests of liquid-hydrogen absorbers for the MUCOOL R&D program and, now, for high-power beam tests of absorbers, high-gradient rf cavities in the presence of magnetic fields (including gas-filled cavities), and other prototype muon-cooling apparatus. The experimental scenarios being developed for muon facilities involve collection, capture, and cooling of large-emittance, high-intensity muon beams--{approx}10{sup 13} muons, so that conclusive tests of the apparatus require full Linac beam, which is 1.6 x 10{sup 13} p/pulse. To support the muon cooling facility, this new primary beamline extracts and transports beam directly from the Linac to the test facility. The design concept for the MuCool facility is taken from an earlier proposal [1], but modifications were necessary to accommodate high-intensity beam, cryogenics, and the increased scale of the cooling experiments. Further, the line incorporates a specialized section and utilizes a different mode of operation to provide precision measurements of Linac beam parameters. This paper reports on the technical details of the MuCool beamline for both modes.
Date: May 1, 2010
Creator: Moore, Craig D.; Anderson, John; Garcia, Fernanda; Gerardi, Michael; Johnstone, Carol; Kobilarcik, Thomas et al.
Object Type: Article
System: The UNT Digital Library
Developing an Instrumentation Package for in-Water Testing of Marine Hydrokinetic Energy Devices: Preprint (open access)

Developing an Instrumentation Package for in-Water Testing of Marine Hydrokinetic Energy Devices: Preprint

The ocean-energy industry is still in its infancy and device developers have provided their own equipment and procedures for testing. Currently, no testing standards exist for ocean energy devices in the United States. Furthermore, as prototype devices move from the test tank to in-water testing, the logistical challenges and costs grow exponentially. Development of a common instrumentation package that can be moved from device to device is one means of reducing testing costs and providing normalized data to the industry as a whole. As a first step, the U.S. National Renewable Energy Laboratory (NREL) has initiated an effort to develop an instrumentation package to provide a tool to allow common measurements across various ocean energy devices. The effort is summarized in this paper. First, we present the current status of ocean energy devices. We then review the experiences of the wind industry in its development of the instrumentation package and discuss how they can be applied in the ocean environment. Next, the challenges that will be addressed in the development of the ocean instrumentation package are discussed. For example, the instrument package must be highly adaptable to fit a large array of devices but still conduct common measurements. Finally, some …
Date: August 1, 2010
Creator: Nelson, E.
Object Type: Article
System: The UNT Digital Library
Conceptual Design Report for the Irradiated Materials Characterization Laboratory (IMCL) (open access)

Conceptual Design Report for the Irradiated Materials Characterization Laboratory (IMCL)

This document describes the design at a conceptual level for the Irradiated Materials Characterization Laboratory (IMCL) to be located at the Materials and Fuels Complex (MFC) at the Idaho National Laboratory (INL). The IMCL is an 11,000-ft2, Hazard Category-2 nuclear facility that is designed for use as a state of the-art nuclear facility for the purpose of hands-on and remote handling, characterization, and examination of irradiated and nonirradiated nuclear material samples. The IMCL will accommodate a series of future, modular, and reconfigurable instrument enclosures or caves. To provide a bounding design basis envelope for the facility-provided space and infrastructure, an instrument enclosure or cave configuration was developed and is described in some detail. However, the future instrument enclosures may be modular, integral with the instrument, or reconfigurable to enable various characterization environments to be configured as changes in demand occur. They are not provided as part of the facility.
Date: June 1, 2010
Creator: Austad, Stephanie
Object Type: Report
System: The UNT Digital Library
Verification of the Defense Waste Processing Facility Process Digestion Method for the Sludge Batch 6 Qualification Sample (open access)

Verification of the Defense Waste Processing Facility Process Digestion Method for the Sludge Batch 6 Qualification Sample

For each sludge batch that is processed in the Defense Waste Processing Facility (DWPF), the Savannah River National Laboratory (SRNL) confirms applicability of the digestion method to be used by the DWPF lab for elemental analysis of Sludge Receipt and Adjustment Tank (SRAT) receipt samples and SRAT product process control samples.1 DWPF SRAT samples are typically dissolved using a room temperature HF-HNO3 acid dissolution (i.e., DWPF Cold Chem (CC) Method, see DWPF Procedure SW4-15.201) and then analyzed by inductively coupled plasma - atomic emission spectroscopy (ICPAES). In addition to the CC method confirmation, the DWPF lab's mercury (Hg) digestion method was also evaluated for applicability to SB6 (see DWPF procedure 'Mercury System Operating Manual', Manual: SW4-15.204. Section 6.1, Revision 5, Effective date: 12-04-03). This report contains the results and comparison of data generated from performing the Aqua Regia (AR), Sodium Peroxide/Hydroxide Fusion (PF) and DWPF Cold Chem (CC) method digestion of Sludge Batch 6 (SB6) SRAT Receipt and SB6 SRAT Product samples. For validation of the DWPF lab's Hg method, only SRAT receipt material was used and compared to AR digestion results. The SB6 SRAT Receipt and SB6 SRAT Product samples were prepared in the SRNL Shielded Cells, and the …
Date: June 9, 2010
Creator: Click, D.; Jones, M. & Edwards, T.
Object Type: Report
System: The UNT Digital Library
Dynamically tuned high-Q AC-dipole implementation (open access)

Dynamically tuned high-Q AC-dipole implementation

AC-dipole magnets are typically implemented as a parallel LC resonant circuit. To maximize efficiency, it's beneficial to operate at a high Q. This, however, limits the magnet to a narrow frequency range. Current designs therefore operate at a low Q to provide a wider bandwidth at the cost of efficiency. Dynamically tuning a high Q resonant circuit tries to maintain a high efficiency while providing a wide frequency range. The results of ongoing efforts at BNL to implement dynamically tuned high-Q AC dipoles will be presented.
Date: May 2, 2010
Creator: Oddo, P.; Bai, M.; Dawson, W.C.; Meng, W.; Mernick, K.; Pai, C. et al.
Object Type: Article
System: The UNT Digital Library
Idaho National Laboratory Directed Research and Development FY-2009 (open access)

Idaho National Laboratory Directed Research and Development FY-2009

The FY 2009 Laboratory Directed Research and Development (LDRD) Annual Report is a compendium of the diverse research performed to develop and ensure the INL's technical capabilities can support the future DOE missions and national research priorities. LDRD is essential to the INL - it provides a means for the laboratory to pursue novel scientific and engineering research in areas that are deemed too basic or risky for programmatic investments. This research enhances technical capabilities at the laboratory, providing scientific and engineering staff with opportunities for skill building and partnership development. Established by Congress in 1991, LDRD proves its benefit each year through new programs, intellectual property, patents, copyrights, publications, national and international awards, and new hires from the universities and industry, which helps refresh the scientific and engineering workforce. The benefits of INL's LDRD research are many as shown in the tables below. Last year, 91 faculty members from various universities contributed to LDRD research, along with 7 post docs and 64 students. Of the total invention disclosures submitted in FY 2009, 7 are attributable to LDRD research. Sixty three refereed journal articles were accepted or published, and 93 invited presentations were attributable to LDRD research conducted in FY …
Date: March 1, 2010
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Monitoring annealing via carbon dioxide laser heating of defect populations in fused silica surfaces using photoluminescence microscopy (open access)

Monitoring annealing via carbon dioxide laser heating of defect populations in fused silica surfaces using photoluminescence microscopy

Photoluminescence (PL) microscopy and spectroscopy under 266 nm and 355 nm laser excitation are explored as a means of monitoring defect populations in laser-modified sites on the surface of fused silica and their subsequent response to heating to different temperatures via exposure to a CO{sub 2} laser beam. Laser-induced temperature changes were estimated using an analytic solution to the heat flow equation and compared to changes in the PL emission intensity. The results indicate that the defect concentrations decrease significantly with increasing CO{sub 2} laser exposure and are nearly eliminated when the peak surface temperature exceeds the softening point of fused silica ({approx}1900K), suggesting that this method might be suitable for in situ monitoring of repair of defective sites in fused silica optical components.
Date: February 1, 2010
Creator: Raman, R. N.; Matthews, M. J.; Adams, J. J. & Demos, S. G.
Object Type: Article
System: The UNT Digital Library
Observation of a Narrow Near-Threshold Structure in the $J/\psi\phi$ Mass Spectrum in $B^+\to J/\psi\phi K^+$ Decays (open access)

Observation of a Narrow Near-Threshold Structure in the $J/\psi\phi$ Mass Spectrum in $B^+\to J/\psi\phi K^+$ Decays

Observation is reported for a structure near the J/{psi}{phi} threshold in B{sup +} {yields} J/{psi}{phi}K{sup +} decays produced in {bar p}p collisions at {radical}s = 1.96 TeV with a statistical significance of beyond 5 standard deviations. There are 19 {+-} 6 events observed for this structure at a mass of 4143.4{sub -3.0}{sup +2.9}(stat) {+-} 0.6(syst) MeV/c{sup 2} and a width of 15.3{sub -6.1}{sup +10.4}(stat) {+-} 2.5(syst) MeV/c{sup 2}, which are consistent with the previous measurements reported as evidence of the Y(4140).
Date: October 1, 2010
Creator: collaboration, Kai Yi for the CDF
Object Type: Article
System: The UNT Digital Library
Threshold Studies of the Microwave Instability in Electron Storage Rings (open access)

Threshold Studies of the Microwave Instability in Electron Storage Rings

We use a Vlasov-Fokker-Planck program and a linearized Vlasov solver to study the microwave instability threshold of impedance models: (1) a Q = 1 resonator and (2) shielded coherent synchrotron radiation (CSR), and find the results of the two programs agree well. For shielded CSR we show that only two dimensionless parameters, the shielding parameter {Pi} and the strength parameter S{sub csr}, are needed to describe the system. We further show that there is a strong instability associated with CSR, and that the threshold, to good approximation, is given by (S{sub csr})th = 0.5 + 0.12{Pi}. In particular, this means that shielding has little effect in stabilizing the beam for {Pi} {approx}< 2; for larger {Pi} it is effective, with threshold current depending on shielding aperture as h{sup -3/2}. We, in addition, find another instability in the vicinity of {Pi} = 0.7 with a lower threshold, (S{sub csr}){sub th} {approx} 0.2. We find that the threshold to this instability depends strongly on damping time, (S{sub csr}){sub th} {approx} {tau}{sub p}{sup -1/2}, and that the tune spread at threshold is small - both hallmarks of a weak instability.
Date: July 30, 2010
Creator: Bane, K. L. F.; Cai, Y. & Stupakov, G.
Object Type: Article
System: The UNT Digital Library
Opportunities for Open Automated Demand Response in Wastewater Treatment Facilities in California - Phase II Report. San Luis Rey Wastewater Treatment Plant Case Study (open access)

Opportunities for Open Automated Demand Response in Wastewater Treatment Facilities in California - Phase II Report. San Luis Rey Wastewater Treatment Plant Case Study

This case study enhances the understanding of open automated demand response opportunities in municipal wastewater treatment facilities. The report summarizes the findings of a 100 day submetering project at the San Luis Rey Wastewater Treatment Plant, a municipal wastewater treatment facility in Oceanside, California. The report reveals that key energy-intensive equipment such as pumps and centrifuges can be targeted for large load reductions. Demand response tests on the effluent pumps resulted a 300 kW load reduction and tests on centrifuges resulted in a 40 kW load reduction. Although tests on the facility?s blowers resulted in peak period load reductions of 78 kW sharp, short-lived increases in the turbidity of the wastewater effluent were experienced within 24 hours of the test. The results of these tests, which were conducted on blowers without variable speed drive capability, would not be acceptable and warrant further study. This study finds that wastewater treatment facilities have significant open automated demand response potential. However, limiting factors to implementing demand response are the reaction of effluent turbidity to reduced aeration load, along with the cogeneration capabilities of municipal facilities, including existing power purchase agreements and utility receptiveness to purchasing electricity from cogeneration facilities.
Date: August 20, 2010
Creator: Thompson, Lisa; Lekov, Alex; McKane, Aimee & Piette, Mary Ann
Object Type: Report
System: The UNT Digital Library