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Health, Safety, and Environmental Screening and Ranking Frameworkfor Geologic CO2 Storage Site Selection (open access)

Health, Safety, and Environmental Screening and Ranking Frameworkfor Geologic CO2 Storage Site Selection

This report describes a screening and ranking framework(SRF) developed to evaluate potential geologic carbon dioxide (CO2)storage sites on the basis of health, safety, and environmental (HSE)risk arising from possible CO2 leakage. The approach is based on theassumption that HSE risk due to CO2 leakage is dependent on three basiccharacteristics of a geologic CO2 storage site: (1) the potential forprimary containment by the target formation, (2) the potential forsecondary containment if the primary formation leaks, and (3) thepotential for attenuation and dispersion of leaking CO2 if the primaryformation leaks and secondary containment fails. The framework isimplemented in a spreadsheet in which users enter numerical scoresrepresenting expert opinions or general information available frompublished materials along with estimates of uncertainty to evaluate thethree basic characteristics in order to screen and rank candidate sites.Application of the framework to the Rio Vista Gas Field, Ventura OilField, and Mammoth Mountain demonstrates the approach. Refinements andextensions are possible through the use of more detailed data or modelresults in place of property proxies. Revisions and extensions to improvethe approach are anticipated in the near future as it is used and testedby colleagues and collaborators.
Date: March 15, 2006
Creator: Oldenburg, Curtis M.
System: The UNT Digital Library
Uncertainty in the reactive transport model response to analkaline perturbation in a clay formation (open access)

Uncertainty in the reactive transport model response to analkaline perturbation in a clay formation

The mineral alteration in the concrete barrier and in the clay formation around long-lived intermediate-level radioactive waste in the French deep geological disposal concept is evaluated using numerical modeling. There are concerns that the mineralogical composition of the surrounded clay will not be stable under the high alkaline pore fluid conditions caused by concrete (pH {approx} 12). Conversely, the infiltration of CO{sub 2}-rich groundwater from the clay formation into initially unsaturated concrete, at the high temperature (T {approx} 70 C) produced from the decay of radionuclides, could cause carbonation, thereby potentially affecting critical performance functions of this barrier. This could also lead to significant changes in porosity, which would affect aqueous diffusive transport of long-lived radionuclides. All these processes are therefore intimately coupled and advanced reactive transport models are required for long-term performance assessment. The uncertainty in predictions of these models is one major question that must be answered. A mass-transfer model response to an alkaline perturbation in clay with standard model values is first simulated using the two-phase non-isothermal reactive transport code TOUGHREACT. The selection of input parameters is thereafter designed to sample uncertainties in a wide range of physico-chemical processes without making a priori assumptions about the relative …
Date: March 15, 2006
Creator: Burnol, A.; Blanc, P.; Xu, T.; Spycher, N. & Gaucher, E. C.
System: The UNT Digital Library
Comparisons Between Experimental Measurments and Numerical Simulations of Spheromak Formation in SSPX (open access)

Comparisons Between Experimental Measurments and Numerical Simulations of Spheromak Formation in SSPX

Data from a recently installed insertable magnetic probe array in the Sustained Spheromak Physics Experiment (SSPX) [E. B. Hooper et al., Nucl. Fusion 39, 863 (1999)] is compared against NIMROD [C. R. Sovinec et al., J. Comp. Phys. 195, 355 (2004)], a full 3D resistive magnetohydrodynamic code that is used to simulate SSPX plasmas. The experiment probe consists of a linear array of chip inductors arranged in clusters that are spaced every 2 cm, and spans the entire machine radius at the flux conserver midplane. Both the experiment and the numerical simulations show the appearance, shortly after breakdown, of a column with a hollow current profile that precedes magnetic reconnection, a process essential to the formation of closed magnetic flux surfaces. However, there are differences between the experiment and the simulation in how the column evolves after it is formed. These differences are studied to help identify the mechanisms that eventually lead to closed-flux surfaces (azimuthally averaged) and flux amplification, which occur in both the experiment and the simulation.
Date: March 15, 2006
Creator: Romero-Talam?s, C. A.; Hooper, E. B.; Hill, D. N.; Cohen, B. I.; McLean, H. S.; Wood, R. D. et al.
System: The UNT Digital Library
Taming the Runaway Problem of Inflationary Landscapes (open access)

Taming the Runaway Problem of Inflationary Landscapes

A wide variety of vacua, and their cosmological realization, may provide an explanation for the apparently anthropic choices of some parameters of particle physics and cosmology. If the probability on various parameters is weighted by volume, a flat potential for slow-roll inflation is also naturally understood, since the flatter the potential the larger the volume of the sub-universe. However, such inflationary landscapes have a serious problem, predicting an environment that makes it exponentially hard for observers to exist and giving an exponentially small probability for a moderate universe like ours. A general solution to this problem is proposed, and is illustrated in the context of inflaton decay and leptogenesis, leading to an upper bound on the reheating temperature in our sub-universe. In a particular scenario of chaotic inflation and non-thermal leptogenesis, predictions can be made for the size of CP violating phases, the rate of neutrinoless double beta decay and, in the case of theories with gauge-mediated weak scale supersymmetry, for the fundamental scale of supersymmetry breaking.
Date: March 15, 2006
Creator: Hall, Lawrence J.; Watari, Taizan & Yanagida, T. T.
System: The UNT Digital Library
Detecting estrogenic activity in water samples withestrogen-sensitive yeast cells using spectrophotometry and fluorescencemicroscopy (open access)

Detecting estrogenic activity in water samples withestrogen-sensitive yeast cells using spectrophotometry and fluorescencemicroscopy

Environmental estrogens are environmental contaminants that can mimic the biological activities of the female hormone estrogen in the endocrine system, i.e. they act as endocrine disrupters. Several substances are reported to have estrogen-like activity or estrogenic activity. These include steroid hormones, synthetic estrogens (xenoestrogens), environmental pollutants and phytoestrogens (plant estrogens). Using the chromogenic substrate ortho-nitrophenyl-{beta}-D-galactopyranoside (ONPG) we show that an estrogen-sensitive yeast strain RMY/ER-ERE, with human estrogen receptor (hER{alpha}) gene and the lacZ gene which encodes the enzyme {beta}-galactosidase, is able to detect estrogenic activity in water samples over a wide range of spiked concentrations of the hormonal estrogen 17{beta}-estradiol (E2). Ortho-nitrophenol (ONP), the yellow product of this assay can be detected using spectrophotometry but requires cell lysis to release the enzyme and allow product formation. We improved this aspect in a fluorogenic assay by using fluorescein di-{beta}-D-galactopyranoside (FDG) as a substrate. The product was visualized using fluorescence microscopy without the need to kill, fix or lyse the cells. We show that in live yeast cells, the uptake of E2 and the subsequent production of {beta}-galactosidase enzyme occur quite rapidly, with maximum enzyme-catalyzed fluorescent product formation evident after about 30 minutes of exposure to E2. The fluorogenic assay was applied …
Date: March 15, 2006
Creator: Wozei, E.; Holman, H-Y.N.; Hermanowicz, S.W. & S., Borglin
System: The UNT Digital Library
Proposal for a High-Brightness Pulsed Electron Source (open access)

Proposal for a High-Brightness Pulsed Electron Source

We propose a novel scheme for a high-brightness pulsedelectron source, which has the potential for many useful applications inelectron microscopy, inverse photo-emission, low energy electronscattering experiments, and electron holography. A description of theproposed scheme is presented.
Date: March 15, 2006
Creator: Zolotorev, Max; Commins, Eugene D.; Heifets, Sam & Sannibale,Fernando
System: The UNT Digital Library
Structural proteomics of minimal organisms: conservation ofprotein fold usage and evolutionary implications (open access)

Structural proteomics of minimal organisms: conservation ofprotein fold usage and evolutionary implications

Background: Determining the complete repertoire of proteinstructures for all soluble, globular proteins in a single organism hasbeen one of the major goals of several structural genomics projects inrecent years. Results: We report that this goal has nearly been reachedfor several "minimal organisms"--parasites or symbionts with reducedgenomes--for which over 95 percent of the soluble, globular proteins maynow be assigned folds, overall 3-D backbone structures. We analyze thestructures of these proteins as they relate to cellular functions, andcompare conservation off old usage between functional categories. We alsocompare patterns in the conservation off olds among minimal organisms andthose observed between minimal organisms and other bacteria. Conclusion:We find that proteins performing essential cellular functions closelyrelated to transcription and translation exhibit a higher degree ofconservation in fold usage than proteins in other functional categories.Folds related to transcription and translation functional categories werealso over represented in minimal organisms compared to otherbacteria.
Date: March 15, 2006
Creator: Chandonia, John-Marc & Kim, Sung-Hou
System: The UNT Digital Library
Compact Superconducting Final Focus Magnet Options for the ILC (open access)

Compact Superconducting Final Focus Magnet Options for the ILC

The QD0 quadrupole, the final focus magnet closest to the Interaction Point (IP) for the ILC 20 mr crossing angle layout, must provide strong focusing yet be adjustable to accommodate collision energy changes for energy scans and low energy calibration running. It must also be compact to allow disrupted beam and Beamstrahlung coming from the IP to pass outside into an independent instrumented beam line that leads to a high-power beam absorber. In designing QD0 we take advantage of recent BNL experience making direct wind superconducting magnets. Here we review important considerations for the present design, report on progress producing a prototype, describe our compact quadrupole concept in greater detail, and relate this work to other ILC design challenges.
Date: March 15, 2006
Creator: Parker, B.; Anerella, M.; Escallier, J.; Harrison, M.; He, P.; Jain, A. K. et al.
System: The UNT Digital Library
Considerations on Beam Quality Control in MIT X-Ray FEL (open access)

Considerations on Beam Quality Control in MIT X-Ray FEL

The x-ray FEL at MIT is one example of a design for a new generation linac-based light source. Such a new machine requires very high quality electron beams. Besides the usual requirements on beam parameters such as emittance, energy spread, peak current, there are new challenges emerging in the design studies, e.g., the arrival timing of electron beam must reach precision below tens of femtoseconds level to ensure the laser seed overlaps the desired sections of electron bunch in the multiple-stage HGHG process. In this paper we report the progress on design optimization towards high quality and low sensitivity beams.
Date: March 15, 2006
Creator: Wang, D.; Graves, W.; Wang, D.; Zwart, T.; Emma, P.; Wu, J. et al.
System: The UNT Digital Library
Heat Deposition in Positron Sources for ILC (open access)

Heat Deposition in Positron Sources for ILC

In the International Linear Collider (ILC) positron source, multi-GeV electrons or multi-MeV photons impinge on a metal target to produce the needed positrons in the resulting electromagnetic showers. The incoming beam power is hundreds of kilowatts. Various computer programs -- such as FLUKA or MARS -- can calculate how the incoming beam showers in the target and can track the particle showers through the positron source system. Most of the incoming energy ends up as heat in the various positron source elements. This paper presents results from such calculations and their impact on the design of a positron source for the ILC.
Date: March 15, 2006
Creator: Bharadwaj, V.; Pitthan, R.; Sheppard, J.; Vincke, H. & Wang, J. W.
System: The UNT Digital Library
Studies of Room Temperature Accelerator Structures for the ILC Positron Source (open access)

Studies of Room Temperature Accelerator Structures for the ILC Positron Source

There are many challenges in the design of the normal-conducting portion of the ILC positron injector system such as achieving adequate cooling with the high RF and particle loss heating, and sustaining high accelerator gradients during millisecond-long pulses in a strong magnetic field. The proposed design for the positron injector contains both standing-wave and traveling-wave L-band accelerator structures for high RF efficiency, low cost and ease of fabrication. This paper presents results from several studies including particle energy deposition for both undulator based and conventional positron sources, cooling system design, accelerator structure optimization, RF pulse heating, cavity frequency stabilization, and RF feed system design.
Date: March 15, 2006
Creator: Wang, J. W.; Adolphsen, C.; Bharadwaj, V.; Bowden, G. B.; Dolgashev, V. A.; Jones, R. M. et al.
System: The UNT Digital Library
Post-Irradiation Properties of Candidate Materials for High-Power Targets (open access)

Post-Irradiation Properties of Candidate Materials for High-Power Targets

The desire of the high-energy-physics community for more intense secondary particle beams motivates the development of multi-megawatt, pulsed proton sources. The targets needed to produce these secondary particle beams must be sufficiently robust to withstand the intense pressure waves arising from the high peak-energy deposition which an intense pulsed beam will deliver. In addition, the materials used for the targets must continue to perform in a severe radiation environment. The effect of the beam induced pressure waves can be mitigated by use of target materials with high-yield strength and/or low coefficient of thermal expansion (CTE). We report here first results of an expanded study of the effects of irradiation on several additional candidate materials with high strength (AlBeMet, beryllium, Ti-V6-Al4) or low CTE (a carbon-carbon composite, a new Toyota ''gum'' metal alloy, Super-Invar).
Date: March 15, 2006
Creator: Kirk, H. G.; Ludewig, H.; Mausner, L. F.; Simos, N.; Thieberger, P.; Hayato, Y. et al.
System: The UNT Digital Library
Comparison of Beam-Based Alignment Algorithms for the ILC (open access)

Comparison of Beam-Based Alignment Algorithms for the ILC

The main linac of the International Linear Collider (ILC) requires more sophisticated alignment techniques than those provided by survey alone. Various Beam-Based Alignment (BBA) algorithms have been proposed to achieve the desired low emittance preservation. Dispersion Free Steering, Ballistic Alignment and the Kubo method are compared. Alignment algorithms are also tested in the presence of an Earth-like stray field.
Date: March 15, 2006
Creator: Smith, J.C.; Gibbons, L.; Patterson, J.R.; Rubin, D.L.; /Cornell U., LEPP; Sagan, D. et al.
System: The UNT Digital Library