DESIGN OF THE DEMOSNTRATION BULK VITRIFICATION SYSTEM FOR THE SUPPLEMENTAL TREATMENT OF LOW ACTIVITY TANK WASTE AT HANFORD (open access)

DESIGN OF THE DEMOSNTRATION BULK VITRIFICATION SYSTEM FOR THE SUPPLEMENTAL TREATMENT OF LOW ACTIVITY TANK WASTE AT HANFORD

In June 2004, the Demonstration Bulk Vitrification System (DBVS) was initiated with the intent to design, construct, and operate a full-scale bulk vitrification pilot-plant to treat low-activity tank waste from Hanford Tank 241-S-109. The DBVS facility uses In-Container Vitrification{trademark} (ICV{trademark}) at the core of the treatment process. The basic process steps combine liquid low-activity waste (LAW) and glassformers; dry the mixture; and then vitrify the mixture in a batch feed-while-melt process in a refractory lined steel container. Off-gases are processed through a state-of-the-art air pollution control system including sintered-metal filtration, thermal oxidation, acid gas scrubbing, and high-efficiency particulate air (HEPA) and high-efficiency gas adsorber (HEGA) filtration. Testing has focused on development and validation of the waste dryer, ICV, and sintered-metal filters (SMFs) equipment, operations enhancements, and glass formulation. With a parallel testing and design process, testing has allowed improvements to the DBVS equipment configuration and operating methodology, since its original inception. Design improvements include optimization of refractory panels in the ICV, simplifying glassformer addition equipment, increasing the number of waste feed chutes to the ICV, and adding capability for remote clean-out of piping, In addition, the U.S. Department of Energy (DOE) has provided an independent review of the entire DBVS …
Date: February 14, 2008
Creator: JE, VAN BEEK
System: The UNT Digital Library
Decomposition of the Multistatic Response Matrix and Target Characterization (open access)

Decomposition of the Multistatic Response Matrix and Target Characterization

Decomposition of the time-reversal operator for an array, or equivalently the singular value decomposition of the multistatic response matrix, has been used to improve imaging and localization of targets in complicated media. Typically, each singular value is associated with one scatterer even though it has been shown in several cases that a single scatterer can generate several singular values. In this paper we review the analysis of the time-reversal operator (TRO), or equivalently the multistatic response matrix (MRM), of an array system and a small target. We begin with two-dimensional scattering from a small cylinder then show the results for a small non-spherical target in three dimensions. We show that the number and magnitudes of the singular values contain information about target composition, shape, and orientation.
Date: February 14, 2008
Creator: Chambers, D H
System: The UNT Digital Library
Versatile microbial surface-display for environmental remediation and biofuels production (open access)

Versatile microbial surface-display for environmental remediation and biofuels production

Surface display is a powerful technique that utilizes natural microbial functional components to express proteins or peptides on the cell exterior. Since the reporting of the first surface-display system in the mid-1980s, a variety of new systems have been reported for yeast, Gram-positive and Gram-negative bacteria. Non-conventional display methods are emerging, eliminating the generation of genetically modified microorganisms. Cells with surface display are used as biocatalysts, biosorbents and biostimulants. Microbial cell-surface display has proven to be extremely important for numerous applications ranging from combinatorial library screening and protein engineering to bioremediation and biofuels production.
Date: February 14, 2008
Creator: Wu, Cindy H.; Mulchandani, Ashok & Chen, wilfred
System: The UNT Digital Library
Molecular Dynamics Simulations of Temperature Equilibration in Dense Hydrogen (open access)

Molecular Dynamics Simulations of Temperature Equilibration in Dense Hydrogen

The temperature equilibration rate in dense hydrogen (for both T{sub i} > T{sub e} and T{sub i} < T{sub e}) has been calculated with large-scale molecular dynamics simulations for temperatures between 10 and 300 eV and densities between 10{sup 20}/cc to 10{sup 24}/cc. Careful attention has been devoted to convergence of the simulations, including the role of semiclassical potentials. We find that for Coulomb logarithms L {approx}> 1, Brown-Preston-Singleton [Brown et al., Phys. Rep. 410, 237 (2005)] with the sub-leading corrections and the fit of Gericke-Murillo-Schlanges [Gericke et al., PRE 65, 036418 (2003)] to the T-matrix evaluation of the collision operator, agrees with the MD data to within the error bars of the simulation. For more strongly-coupled plasmas where L {approx}< 1, our numerical results are consistent with the fit of Gericke-Murillo-Schlanges.
Date: February 14, 2008
Creator: Glosli, J; Graziani, F; More, R; Murillo, M; Streitz, F; Surh, M et al.
System: The UNT Digital Library
An Implementation and Evaluation of the AMLS Method for SparseEigenvalue Problems (open access)

An Implementation and Evaluation of the AMLS Method for SparseEigenvalue Problems

We describe an efficient implementation and present aperformance study of an algebraic multilevel sub-structuring (AMLS)method for sparse eigenvalue problems. We assess the time and memoryrequirements associated with the key steps of the algorithm, and compareitwith the shift-and-invert Lanczos algorithm in computational cost. Oureigenvalue problems come from two very different application areas: theaccelerator cavity design and the normal mode vibrational analysis of thepolyethylene particles. We show that the AMLS method, when implementedcarefully, is very competitive with the traditional method in broadapplication areas, especially when large numbers of eigenvalues aresought.
Date: February 14, 2006
Creator: Gao, Weiguo; Li, Xiaoye S.; Yang, Chao & Bai, Zhaojun
System: The UNT Digital Library
Preliminary Evaluation of a Portable Handheld Combined Gamma and Neutron Directional Isotopic Identifying Detector (open access)

Preliminary Evaluation of a Portable Handheld Combined Gamma and Neutron Directional Isotopic Identifying Detector

Purpose: To simulate the performance of a portable dual gamma and neutron identification detector array with dual directional detection capability for preliminary algorithm evaluation. Experimental procedures: Monte Carlo N-Particle (MCNP) analysis on a compact array of borated polyvinyl toluene light pipes and photomultiplier tubes, standard spectral histogramming, and directional detection capability simulations. Results: Results demonstrate that the detector system is fully capable of correcting for background variations when identifying common gamma and neutron sources while simultaneously providing source location direction estimates. Familiar anthropogenic isotopes are readily identified such as Am-241, Cs-137, Cf-252 and Co-60. Directional resolution is estimated to be within approximately 15 degrees. Specifically, all features expected for the array have been demonstrated to be credible through MCNP analysis. Conclusions: Use of this handheld dual neutron and gamma spectrometer has the promise of widespread applicability. By ultimately correlating MCNP results with empirical measurements, substantial confidence can be placed on predicting detector response to sufficiently similar spectral sources under alternate experimental configurations. Use of the detector has substantial promise for operational health physics applications.
Date: February 14, 2008
Creator: Hayes, Robert
System: The UNT Digital Library
R-LODs: Fast LOD-Based Ray Tracing of Massive Models (open access)

R-LODs: Fast LOD-Based Ray Tracing of Massive Models

We present a novel LOD (level-of-detail) algorithm to accelerate ray tracing of massive models. Our approach computes drastic simplifications of the model and the LODs are well integrated with the kd-tree data structure. We introduce a simple and efficient LOD metric to bound the error for primary and secondary rays. The LOD representation has small runtime overhead and our algorithm can be combined with ray coherence techniques and cache-coherent layouts to improve the performance. In practice, the use of LODs can alleviate aliasing artifacts and improve memory coherence. We implement our algorithm on both 32bit and 64bit machines and able to achieve up to 2.20 times improvement in frame rate of rendering models consisting of tens or hundreds of millions of triangles with little loss in image quality.
Date: February 14, 2006
Creator: Yoon, S.; Lauterbach, C. & Manocha, D.
System: The UNT Digital Library
Development of the Low Swirl Injector for Fuel-Flexible Gas Turbines (open access)

Development of the Low Swirl Injector for Fuel-Flexible Gas Turbines

Industrial gas turbines are primarily fueled with natural gas. However, changes in fuel cost and availability, and a desire to control carbon dioxide emissions, are creating pressure to utilize other fuels. There is an increased interest in the use of fuels from coal gasification, such as syngas and hydrogen, and renewable fuels, such as biogas and biodiesel. Current turbine fuel injectors have had years of development to optimize their performance with natural gas. The new fuels appearing on the horizon can have combustion properties that differ substantially from natural gas. Factors such as turbulent flame speed, heat content, autoignition characteristics, and range of flammability must be considered when evaluating injector performance. The low swirl injector utilizes a unique flame stabilization mechanism and is under development for gas turbine applications. Its design and mode of operation allow it to operate effectively over a wide range of conditions. Studies conducted at LBNL indicate that the LSI can operate on fuels with a wide range of flame speeds, including hydrogen. It can also utilize low heat content fuels, such as biogas and syngas. We will discuss the low swirl injector operating parameters, and how the LSC performs with various alternative fuels.
Date: February 14, 2007
Creator: Littlejohn, D.; Cheng, R.K.; Nazeer,W.A. & Smith, K.O
System: The UNT Digital Library
Automatic Generation of Data Types for Classification of Deep Web Sources (open access)

Automatic Generation of Data Types for Classification of Deep Web Sources

A Service Class Description (SCD) is an effective meta-data based approach for discovering Deep Web sources whose data exhibit some regular patterns. However, it is tedious and error prone to create an SCD description manually. Moreover, a manually created SCD is not adaptive to the frequent changes of Web sources. It requires its creator to identify all the possible input and output types of a service a priori. In many domains, it is impossible to exhaustively list all the possible input and output data types of a source in advance. In this paper, we describe machine learning approaches for automatic generation of the data types of an SCD. We propose two different approaches for learning data types of a class of Web sources. The Brute-Force Learner is able to generate data types that can achieve high recall, but with low precision. The Clustering-based Learner generates data types that have a high precision rate, but with a lower recall rate. We demonstrate the feasibility of these two learning-based solutions for automatic generation of data types for citation Web sources and presented a quantitative evaluation of these two solutions.
Date: February 14, 2005
Creator: Ngu, A. H.; Buttler, D. J. & Critchlow, T. J.
System: The UNT Digital Library
The Importance of Geometric Nonlinearity in Finite Element Studies of Yielding in Trabecular Bone (open access)

The Importance of Geometric Nonlinearity in Finite Element Studies of Yielding in Trabecular Bone

None
Date: February 14, 2005
Creator: Kinney, J H & Stolken, J S
System: The UNT Digital Library
Using Biofuel Tracers to Study Alternative Combustion Regimes (open access)

Using Biofuel Tracers to Study Alternative Combustion Regimes

Interest in the use of alternative fuels and combustion regimes is increasing as the price of petroleum climbs. The inherently higher efficiency of Diesel engines has led to increased adoption of Diesels in Europe, capturing approximately 40% of the new passenger car market. Unfortunately, lower CO{sub 2} emissions are countered with higher nitrogen oxides (NOx) and particulate matter (PM) emissions, and higher noise. Noise and PM have traditionally been the obstacles toward consumer acceptance of Diesel passenger cars in North America, while NOx (a key component in photochemical smog) has been more of an engineering challenge. Diesels are lean burning (combustion with excess oxygen) and reducing NOx to N2 in an oxygen rich environment is difficult. Adding oxygenated compounds to the fuel helps reduce PM emissions, but relying on fuel alone to reduce PM is unrealistic. Keeping peak combustion temperature below 1700 K prevents NOx formation. Altering the combustion regime to burn at temperatures below the NOx threshold and accept a wide variety of fuels seems like a promising alternative for future engines. Homogeneous Charge Compression Ignition (HCCI) is a possible solution. Fuel and air are well mixed prior to intake into a cylinder (homogeneous charge) and ignition occurs by …
Date: February 14, 2006
Creator: Mack, J. H.; Flowers, D. L.; Buchholz, B. A. & Dibble, R. W.
System: The UNT Digital Library
Site Characterization for CO2 Geologic Storage and Vice Versa -The Frio Brine Pilot as a Case Study (open access)

Site Characterization for CO2 Geologic Storage and Vice Versa -The Frio Brine Pilot as a Case Study

Careful site characterization is critical for successfulgeologic sequestration of CO2, especially for sequestration inbrine-bearing formations that have not been previously used for otherpurposes. Traditional site characterization techniques such asgeophysical imaging, well logging, core analyses, interference welltesting, and tracer testing are all valuable. However, the injection andmonitoring of CO2 itself provides a wealth of additional information.Rather than considering a rigid chronology in which CO2 sequestrationoccurs only after site characterization is complete, we recommend thatCO2 injection and monitoring be an integral part of thesite-characterization process. The advantages of this approach arenumerous. The obvious benefit of CO2 injection is to provide informationon multi-phase flow properties, which cannot be obtained from traditionalsitecharacterization techniques that examine single-phase conditions.Additionally, the low density and viscosity of CO2 compared to brinecauses the two components to flow through the subsurface differently,potentially revealing distinct features of the geology. Finally, tounderstand sequestered CO2 behavior in the subsurface, there is nosubstitute for studying the movement of CO2 directly. Making CO2injection part of site characterization has practical benefits as well.The infrastructure for surface handling of CO2 (compression, heating,local storage) can be developed, the CO2 injection process can bedebugged, and monitoring techniques can be field-tested. Prior to actualsequestration, small amounts of CO2 may be …
Date: February 14, 2006
Creator: Doughty, Christine
System: The UNT Digital Library
Evolutionary Processes in Multiple Systems (open access)

Evolutionary Processes in Multiple Systems

There are several ways in which triple stars can evolve in somewhat unusual ways. They discuss two situations where Case A Roche-lobe overflow, followed by a merger, can produce anomalous wide binaries such as {gamma} Per; and Kozai cycles in triples with non-parallel orbits, which can produce merged rapidly-rotating stars like AB Dor, and which can also lead to the delayed ejection of one component of a multiple, as may have been observed in T Tau in 1998.
Date: February 14, 2006
Creator: Eggleton, P P & Kisseleva-Eggleton, L
System: The UNT Digital Library
Recent Measurements And Plans for the SLAC Compton X-Ray Source (open access)

Recent Measurements And Plans for the SLAC Compton X-Ray Source

A compact source of monoenergetic X-rays, generated via Compton backscattering, has been developed in a collaboration between U.C Davis and SLAC. The source consists of a 5.5 cell X-band photoinjector, a 1.05 m long high gradient accelerator structure and an interaction chamber where a high power (TW), short pulse (sub-ps) infrared laser beam is brought into a nearly head-on collision with a high quality focused electron beam. Successful completion of this project will result in the capability of generating a monoenergetic X-ray beam, continuously tunable from 20 - 85 keV. We have completed a series of measurements leading up to the generation of monoenergetic X-rays. Measurements of essential electron beam parameters and the techniques used in establishing electron/photon collisions will be presented. We discuss the design of an improved interaction chamber, future electro-optic experiments using this chamber and plans for expanding the overall program to the generation of Terahertz radiation.
Date: February 14, 2006
Creator: Vlieks, A. E.; Akre, R.; Caryotakis, G.; DeStefano, C.; Frederick, W. J.; Heritage, J. P. et al.
System: The UNT Digital Library
On Leakage from Geologic Storage Reservoirs of CO2 (open access)

On Leakage from Geologic Storage Reservoirs of CO2

Large amounts of CO2 would need to be injected underground to achieve a significant reduction of atmospheric emissions. The large areal extent expected for CO2 plumes makes it likely that caprock imperfections will be encountered, such as fault zones or fractures, which may allow some CO2 to escape from the primary storage reservoir. Leakage of CO2 could also occur along wellbores. Concerns with escape of CO2 from a primary geologic storage reservoir include (1) acidification of groundwater resources, (2) asphyxiation hazard when leaking CO2 is discharged at the land surface, (3) increase in atmospheric concentrations of CO2, and (4) damage from a high-energy, eruptive discharge (if such discharge is physically possible). In order to gain public acceptance for geologic storage as a viable technology for reducing atmospheric emissions of CO2, it is necessary to address these issues and demonstrate that CO2 can be injected and stored safely in geologic formations.
Date: February 14, 2006
Creator: Pruess, Karsten
System: The UNT Digital Library
Oxygen Isotopes in Chondritic Interplanetary Dust: Parent-Bodies and Nebular Oxygen Reservoirs (open access)

Oxygen Isotopes in Chondritic Interplanetary Dust: Parent-Bodies and Nebular Oxygen Reservoirs

Planetary objects have preserved various amounts of oxygen issued from isotopically different oxygen reservoirs reflecting their origin and physico-chemical history. An {sup 16}O-rich component is preserved in refractory inclusions (CAIs) whereas meteorites matrices are enriched in an {sup 16}O-poor component. The origin of these components is still unclear. The most recent models are based on isotope selective photodissociation of CO in a {sup 16}O-rich nebula/presolr cloud resulting in a {sup 16}O-poor gas in the outer part of the nebula. However because most meteorite components are thought to be formed in the inner 3AU of the solar nebula, the precise isotopic composition of outer solar system components is yet unknown. In that respect, the oxygen isotopic composition of cometary dust is a key to understand the origin of the solar system. The Stardust mission will bring back to the Earth dust samples from comet Wild2, a short period comet from the Jupiter family. A precise determination of the oxygen isotope composition of Wild2 dust grains is essential to decipher the oxygen reservoirs of the outer solar system. However, Stardust samples may be extremely fragmented upon impact in the collector. In addition, interplanetary dust particles (IDPs) collected in the stratosphere are likely …
Date: February 14, 2006
Creator: Aleon, J.; McKeegan, K. D. & Leshin, L.
System: The UNT Digital Library
Design and simulation of a multi-beamlet injector for a highcurrent accelerator (open access)

Design and simulation of a multi-beamlet injector for a highcurrent accelerator

A multi-beamlet approach to a high current ion injector, whereby a large number of beamlets are accelerated and then merged to form a single beam, offers a number of potential advantages over a monolithic single beam injector. These advantages include a smaller transverse footprint, more control over the shaping and aiming of the beam, and more flexibility in the choice of ion sources. A potential drawback however is a larger emittance. In this paper, we seek to understand the merging of the beamlets and how it determines the emittance. When the constraints imposed by beam propagation physics and practical engineering issues are included, the design is reduced to a few free parameters. We describe the physics design of a multi-beamlet injector, and produce a design for an example set of parameters. Extensive use of 2-D and 3-D particle simulations was made in understanding the injector. Design tolerances and sensitivities are discussed in general and in relation to the example.
Date: February 14, 2002
Creator: Grote, David P.; Henestroza, Enrique & Kwan, Joe W.
System: The UNT Digital Library
Study of the radiation damage of Nd-Fe-B permanent magnets. (open access)

Study of the radiation damage of Nd-Fe-B permanent magnets.

Nd-Fe-B permanent magnets are highly desirable for use in the insertion devices of synchrotron radiation sources due to their high remanence, or residual magnetic induction, and intrinsic coercivity. However, the radiation environment within high-energy electron storage rings necessitates the determination of the degree of radiation sensitivity as well as the mechanisms of radiation-induced demagnetization. A 0.5% change in the residual induction due to radiation damage cannot be tolerated in these devices. Sample Nd-Fe-B permanent magnets were irradiated at the Advanced Photon Source (APS) with bending magnet x-rays up to an absorbed dose of approximately 280 Mrad (1 Mrad = 10 kGy). Sample magnets were also irradiated with 60 Co {gamma}-rays up to an absorbed dose of 700 Mrad at the National Institute of Standards and Technology's (NIST) standard gamma irradiation facility. Changes in the residual induction were found to be within the experimental uncertainties for both the x-ray and {gamma}-ray irradiations. Sample Nd-Fe-B permanent magnets were then irradiated at Oak Ridge National Laboratory's (ORNL) Californium User Facility for Neutron Science with fast neutrons up to a total fast fluence of 1.61 x 10{sup 14} n/cm{sup 2} and with thermal neutrons up to a total thermal fluence of 2.94 x 10{sup …
Date: February 14, 2002
Creator: Job, P. K.; Alderman, J. M.; Martin, R. C. & Simmons, C. M.
System: The UNT Digital Library
Present and future electroweak precision measurements and the indirect determination of the mass of the Higgs boson (open access)

Present and future electroweak precision measurements and the indirect determination of the mass of the Higgs boson

We discuss the experimental and theoretical uncertainties on precision electroweak observables and their relationship to the indirect constraints on the Higgs boson mass, MH, in the Standard Model (SM). The critical experimental measurements (M{sub W}, sin{sup 2}{theta}{sub eff}, m{sub t},...) are evaluated in terms of their present uncertainties and their prospects for improved precision at future colliders, and their contribution to the constraints on MH. In addition, the current uncertainties of the theoretical predictions for M{sub W} and sin{sup 2} {theta}{sub eff} due to missing higher order corrections are estimated and expectations and necessary theoretical improvements for future colliders are explored. The constraints from rare B decays are also discussed. Analysis of the present experimental and theoretical precisions yield a current upper bound on M{sub H} of {approx} 200 GeV. Including anticipated improvements corresponding to the prospective situation at future colliders (Tevatron Run II, LHC, LC/GigaZ), we find a relative precision of about 25% to 8% (or better) is achievable in the indirect determination of M{sub H}.
Date: February 14, 2002
Creator: al., U. Baur et
System: The UNT Digital Library
Feasibility of natural circulation heat transport in the ENHS. (open access)

Feasibility of natural circulation heat transport in the ENHS.

An analysis has been carried out of natural circulation thermal hydraulics in both the primary and intermediate circuits of the Encapsulated Nuclear Heat Source (ENHS). It is established that natural circulation enhanced by gas injection into the primary coolant above the core, or the intermediate coolant above the heat exchange zone, is effective in transporting the nominal core power to the steam generators without the attainment of excessive system temperatures. Uncertainties in thermophysical properties and wall friction have a relatively small effect upon the calculated best estimate primary and intermediate coolant system temperature rises.
Date: February 14, 2002
Creator: Sienicki, J. J.
System: The UNT Digital Library
EUV Engineering Test Stand (open access)

EUV Engineering Test Stand

The Engineering Test Stand (ETS) is an EUV laboratory lithography tool. The purpose of the ETS is to demonstrate EUV full-field imaging and provide data required to support production-tool development. The ETS is configured to separate the imaging system and stages from the illumination system. Environmental conditions can be controlled independently in the two modules to maximize EUV throughput and environmental control. A source of 13.4 nm radiation is provided by a laser plasma source in which a YAG laser beam is focused onto a xenon-cluster target. A condenser system, comprised of multilayer-coated mirrors and grazing-incidence mirrors, collects the EUV radiation and directs it onto a-reflecting reticle. A four-mirror, ring-field optical system, having a numerical aperture of 0.1, projects a 4x-reduction image onto the wafer plane. This design corresponds to a resolution of 70nm at a k{sub 1} of 0.52. The ETS is designed to produce full-field images in step: and-scan mode using vacuum-compatible, one-dimension-long-travel magnetically levitated stages for both reticle and wafer. Reticle protection is incorporated into the ETS design. This paper provides a system overview of the ETS design and specifications.
Date: February 14, 2000
Creator: Tichenor, D. A.; Kubiak, G. D.; Replogle, W. C.; Klebanoff, L. E.; Wronosky, J. B.; Hale, L. C. et al.
System: The UNT Digital Library
A Dynamically Adaptive Arbitrary Lagrangian-Eulerian Method for Solution of the Euler Equations (open access)

A Dynamically Adaptive Arbitrary Lagrangian-Eulerian Method for Solution of the Euler Equations

A new method that combines staggered grid arbitrary Lagrangian-Eulerian (ALE) techniques with structured local adaptive mesh refinement (AMR) has been developed for solution of the Euler equations. The novel components of the methods are driven by the need to reconcile traditional AMR techniques with the staggered variables and moving, deforming meshes associated with Lagrange based ALE schemes. We develop interlevel solution transfer operators and interlevel boundary conditions first in the case of purely Lagrangian hydrodynamics, and then extend these ideas into an ALE method by developing adaptive extensions of elliptic mesh relaxation techniques. Conservation properties of the method are analyzed, and a series of test problem calculations are presented which demonstrate the utility and efficiency of the method.
Date: February 14, 2003
Creator: Anderson, R W; Elliott, N S & Pember, R B
System: The UNT Digital Library
Torsional Buckling and Writhing Dynamics of Elastic Cables and DNA (open access)

Torsional Buckling and Writhing Dynamics of Elastic Cables and DNA

Marine cables under low tension and torsion on the sea floor can undergo a dynamic buckling process during which torsional strain energy is converted to bending strain energy. The resulting three-dimensional cable geometries can be highly contorted and include loops and tangles. Similar geometries are known to exist for supercoiled DNA and these also arise from the conversion of torsional strain energy to bending strain energy or, kinematically, a conversion of twist to writhe. A dynamic form of Kirchhoff rod theory is presented herein that captures these nonlinear dynamic processes. The resulting theory is discretized using the generalized-method for finite differencing in both space and time. The important kinematics of cross-section rotation are described using an incremental rotation ''vector'' as opposed to traditional Euler angles or Euler parameters. Numerical solutions are presented for an example system of a cable subjected to increasing twist at one end. The solutions show the dynamic evolution of the cable from an initially straight element, through a buckled element in the approximate form of a helix, and through the dynamic collapse of this helix through a looped form.
Date: February 14, 2003
Creator: Goyal, S; Perkins, N C & Lee, C L
System: The UNT Digital Library
Cost-Effective Sampling of Groundwater Monitoring Wells: A Data Review & Well Frequency Evaluation (open access)

Cost-Effective Sampling of Groundwater Monitoring Wells: A Data Review & Well Frequency Evaluation

Lawrence Livermore National Laboratory (LLNL) uses the Cost-Effective Sampling (CES) program for reviewing groundwater data and optimizing the site's groundwater monitoring plan. The CES program produces a data assessment sheet and a lowest-frequency sampling schedule for each groundwater monitoring location. The assessment sheet and recommended sampling schedule greatly streamline the data review process and provide useful information for regulatory and remedial decision-making. The determination of sampling frequency for a given location is based on trend, variability, and magnitude statistics. The underlying principle is that a location's schedule should be determined primarily by the rate of change in concentrations observed there in the recent past. The larger the rate of change, whether upward or downward, the greater the need for frequent sampling. Conversely, where little change is observed, less sampling is recommended. In 1992, CES was approved by the U.S. EPA - Region IX and the local regulators for use at LLNL, and became part of the LLNL's approved compliance monitoring plan (Lamarre et al. 1996). Applying the CES methodology produced, initially, a 40% reduction in the annual number of required groundwater samples, and with recent optimization of the program a 55% reduction has been produced. This reduction saves LLNL $530,000 …
Date: February 14, 2005
Creator: Ridley, M. & MacQueen, D.
System: The UNT Digital Library