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Classification of Geothermal Resources - An engineering approach

Description: Geothermal resources have been classified into low, intermediate and high enthalpy resources by their reservoir temperatures. The temperature ranges used are arbitrary and there is not a general agreement. Geothermal resources should be classified by two independent thermodynamic properties of their fluids at the wellhead. They should reflect the fluids availability to do work. By setting the triple point of water as the sink condition, and normalising the fluids specific exergies by the maximum specific exergy of dry saturated steam, geothermal resources can be classified into high, medium, and low category resources by their specific exergy indices (SEI) of greater than 0.5, between 0.05 and 0.5, and less than 0.05. These correspond to geothermal fluids having exergies greater than that of dry saturated steam at 1 bar absolute, between saturated water and dry saturated steam at 1 bar absolute, and less than saturated water at 1 bar absolute respectively.
Date: January 24, 1996
Creator: Lee, K.C.
Partner: UNT Libraries Government Documents Department

Progress report on pre-test calculations for the large block test

Description: The U.S. Department of Energy`s (DOE) Yucca Mountain Site Characterization Project (YMP) is investigating the suitability of the Topopah Spring tuff in the thick vadose zone at Yucca Mountain, Nevada, as a host rock for permanent disposal of high-level radioactive waste. As part of the YMP, a group of field tests, referred to as the Large Block Test (LBT), will be conducted on a large electrically heated block of Topopah Spring tuff, isolated at Fran Ridge, Nevada Test Site. The block, which will be 3 x 3 m in horizontal dimensions and 4.5 m in height, will be heated by electrical heaters. The goals of the LBT axe to gain information on the coupled thermal-mechanical-hydrological-chemical processes active in the near-field environment of a repository; to provide field data for testing and calibrating models; and to help the development of measurement systems and techniques. This progress report presents results of on-going numerical modeling calculations carried out in support of the LBT design. An equivalent continuum model with an upper boundary temperature of 60{degrees}C was used to simulate the hydrothermal response of the block to heating over a one-year period. The total heating power was started at 1500 W and later reduced to maintain an approximately uniform temperature of 138-140{degrees}C. For a homogeneous bulk permeability case, the results show the formation of a distinct dry-out zone in and around the heater plane, and well-developed condensation zones above and below the heater plane. For a heterogeneous permeability distribution, the condensation zone above the heater plane was not well developed. This difference in results suggests that water saturation changes might be sensitive to changes in bulk permeability distribution. Rock temperatures were almost unaffected by permeability distribution. Heat flow was dominated by conduction. No liquid flow through the top of the block was predicted.
Date: January 20, 1995
Creator: Lee, K.H.
Partner: UNT Libraries Government Documents Department

Analysis of vadose zone tritium transport from an underground storage tank release using numerical modeling and geostatistics

Description: Numerical and geostatistical analyses show that the artificial smoothing effect of kriging removes high permeability flow paths from hydrogeologic data sets, reducing simulated contaminant transport rates in heterogeneous vadose zone systems. therefore, kriging alone is not recommended for estimating the spatial distribution of soil hydraulic properties for contaminant transport analysis at vadose zone sites. Vadose zone transport if modeled more effectively by combining kriging with stochastic simulation to better represent the high degree of spatial variability usually found in the hydraulic properties of field soils. However, kriging is a viable technique for estimating the initial mass distribution of contaminants in the subsurface.
Date: September 1, 1997
Creator: Lee, K.H.
Partner: UNT Libraries Government Documents Department

Second progress report on pre-test calculations for the large block test

Description: The US Department of Energy`s (DOE) Yucca Mountain Site Characterization Project (YMP) is investigating the suitability of the Topopah Spring tuff in the thick vadose zone at Yucca Mountain, Nevada, as a host rock for permanent disposal of high-level radioactive waste. As part of the YMP, a group of field tests, called the Large Block Test (LBT), will be conducted on a large electrically heated block of Topopah Spring tuff. The block will be heated by electrical heaters. The goals of the LBT are to gain information on the coupled thermal-mechanical-hydrological-chemical processes that will be active in the near-field environment of a repository; to provide field data for testing and calibrating models; and to help in the development of measurement systems and techniques. In this second progress report, we present results of the final set of numerical modeling calculations performed in support of the LBT design. The results include block temperatures and heat fluxes across the surfaces. The results are applied primarily to the design of guard heaters to enforce adiabatic conditions along the block walls. Conduction-only runs are adequate to estimate the thermal behavior of the system, because earlier calculations showed that heat transfer in the block is expected to be dominated by conduction. In addition, conduction-only runs can be made at substantially shorter execution times than full hydrothermal runs. We also run a two-dimensional, hydrothermal, discrete fracture model, with 200-{mu}m vertical fractures parallel to the heaters and occurring at a uniform spacing of 30 cm. The results show the development of distinct dryout and recondensation zones. The dryout zones are thickest at the fractures and thinnest in the matrix midway between the fractures.
Date: November 15, 1995
Creator: Lee, K.H.
Partner: UNT Libraries Government Documents Department

Multifrequency crosshole EM imaging for reservoir characterization. FY 1994 annual report

Description: Electrical conductivity of sedimentary rocks is controlled by the porosity, hydraulic permeability, temperature, saturation, and the pore fluid conductivity. These rock parameters play important roles in the development and production of hydrocarbon (petroleum and natural gas) resources. For these reasons, resistivity well logs have long been used by geologists and reservoir engineers in petroleum industries to map variations in pore fluid, to distinguish between rock types, and to determine completion intervals in wells. Reservoir simulation and process monitoring rely heavily on the physical characteristics of the reservoir model. Over a period of three years (1991-1993) there was an initial phase of crosshole EM technique development via an informal partnership between LLNL and LBL. Researchers developed field instrumentation to apply to oil field for monitoring EOR thermal processes. Specifically, a prototype single-frequency instrumentation was developed and with this system we have conducted field surveys in four separate locations. Theory and software were developed to interpret these data by providing subsurface images of the electrical conductivity. In spite of our initial success in developing practical EM techniques, we still had severe instrumentation limitations and shortcomings in interpretation for other than simple structures. The field equipment was designed to work only at a single frequency at a time and the transmitter must be opened to change frequencies. The equipment was also significantly noiser at higher frequencies. For high-resolution applications we need to take full advantage of the resolution inherent in the data. The development of a high-resolution subsurface conductivity imaging methods would have benefits far beyond the petroleum application. Such techniques would be very useful in environmental applications, mineral and geothermal exploration and for civil engineering applications.
Date: June 1, 1995
Creator: Lee, K.H.
Partner: UNT Libraries Government Documents Department

Sorption Characteristics of Aqueous Co(II) on Preformed Iron Ferrite Impregnated into Phenolsulphonic Formaldehyde Resin

Description: A series of stepwise procedures to prepare a new organic-inorganic composite magnetic resin with phenolsulphonicformaldehyde and freshly formed iron ferrite was established, based upon wet-and-neutralization method for synthesizing iron ferrite and pearl-polymerization method for synthesizing rigid bead-type composite resin. The composite resin prepared by the above method shows stably high removal efficiency (maximally over 3.1 meq./gresin) to Co(II) species from wastewater in a wide range of solution pH. The wide range of applicable solution pH (i.e. pH 4.09 to 10.32) implies that the composite resin overcomes the limitations of the conventional ferrite process that is practically applicable only to alkaline conditions. It has been found that both ion exchange (by the organic resin constituent) and surface adsorption (by the inorganic adsorbent constituent) are major reaction mechanisms for removing Co(II) from wastewater, but surface precipitation results in the high sorption capacity to Co(II) beyond normal ion exchange capacity of the phenolsulphonic-formaldehyde resin. Standard enthalpy change derived from van't Hoff equation is 32.0 kJ{center_dot}mol-1 conforming to the typical range for chemisorption or ion exchange. In a wide range of equilibrium Co(II) concentration, the overall isotherm is qualitatively explained by the generalized adsorption isotherm concept proposed by McKinley. At the experimental conditions where the composite resin shows equivalent selectivity to Co(II) and other competing reagents (i.e. EDTA and Na), the ratios of Co(II) to other chemicals turn out to be 2:1 and 1:221, respectively. In addition, the selectivity of the PSF-F to Co(II) species is very high (about 72% of Co(II)-removal efficiency) even when the molar ratio of Co(II) to Ca(II) is 1:30. It is anticipated that the composite resin can also be used for column-operation with process-control by applying external magnetic field, since the rigid bead-type composite resin shows magnetic-susceptibility due to its paramagnetic inorganic constituent (i.e. iron ferrite).
Date: February 26, 2002
Creator: Lee, K. J. & Kim, Y. K.
Partner: UNT Libraries Government Documents Department

A SOLUTION FOR TM-MODE PLANE WAVES INCIDENT ON A TWO-DIMENSIONAL INHOMOGENEITY

Description: A solution for the electromagnetic fields scattered from a two-dimensional inhomogeneity in a conducting half space has been obtained for an incident TM mode plane wave; the magnetic field is polarized parallel to the strike of the inhomogeneity. The approach has been to determine the scattering currents within the inhomogeneity using an integral equation for the electric fields. This solution is similar in concept to earlier studies of TE mode scattering from two-dimensional inhomogeneities, and it completes the analysis of the scattering of arbitrary plane waves using the integral equation approach. For simple bodies in the earth integral equation solution offers significant computational advantages over alternate finite element or finite difference methods of solution.
Date: March 1, 1980
Creator: Lee, K.H. & Morrision, H.F.
Partner: UNT Libraries Government Documents Department

Air-injection field tests to determine the effect of a heat cycle on the permeability of welded tuff

Description: As part of a series of prototype tests conducted in preparation for site characterization of the potential nuclear-waste repository site at Yucca Mountain, Nevada, air-injection tests were conducted in the welded tuffs in G-Tunnel at the Nevada Test Site. The objectives were to characterize the permeability of the highly fractured tuff around a horizontal heater emplacement borehole, and to determine the effect of a heating and cooling cycle on the rock-mass permeability. Air was injected into packed-off intervals along the heater borehole. The bulk permeability of the rock adjacent to the test interval and the aperture of fractures intersecting the interval were computed from the air-flow rate, temperature, and pressure at steady state. The bulk permeability of intervals along with borehole varied from a minimum of 0.08 D to a maximum of over 144 D and the equivalent parallel-plate apertures of fractures intersecting the borehole varied from 70 to 589 {mu}m. Higher permeabilities seemed to correlate spatially with the mapped fractures. The rock was then heated for a period of 6.5 months with an electrical-resistive heater installed in the borehole. After heating, the rock was allowed to cool down to the ambient temperature. The highest borehole wall temperature measured was 242{degree}C. Air injection tests were repeated following the heating and cooling cycle, and the results showed significant increases in bulk permeability ranging from 10 to 1830% along the borehole. 8 ref., 6 figs., 3 tabs.
Date: October 1, 1991
Creator: Lee, K.H. & Ueng, Tzou-Shin
Partner: UNT Libraries Government Documents Department

The two polymorphs of N-DNAT, a high nitrogen molecule

Description: A novel azo triazole molecule was prepared. Based on X-ray crystallography data, this molecule, 1,1{prime}-dinitro-3,3{prime}-azo-1,2,4-triazole (N-DNAT) exists in two forms. The yellow color polymorph has a crystal density of 1.701 g/cm{sup 3}, while the density of the orange crystal is 1.831 g/cm{sup 3}. Data from specific impulse (Isp) calculation indicates that N-DNAT is a potential candidate for propellant applications.
Date: September 1995
Creator: Lee, K. Y. & Chan, M.
Partner: UNT Libraries Government Documents Department

Field air injection tests to determine the effect of a heat cycle on the permeability of welded tuff

Description: As part of a series of prototype tests conducted in preparation for site characterization at Yucca Mountain, air-injection tests were conducted in the welded tuffs in G-Tunnel at the Nevada Test Site. The objectives were to characterize the permeability of the highly fractured tuff around a horizontal heater emplacement borehole, and to determine the effect of a heating and cooling cycle on the rock-mass permeability. Air was injected into packed-off intervals along the heater borehole. The bulk permeability of the rock adjacent to the test interval was computed from the air-flow rate, temperature, and pressure at steady state. The permeability varied from a minimum of 0.08 D to a maximum of over 144 D. Higher permeabilities seemed to correlate spatially with the mapped fractures. The rock was then heated for a period of 6.5 months with an electrical-resistive heater installed in the borehole. After heating, the rock was allowed to cool down to the ambient temperature. the highest borehole wall temperature measured was 242{degrees}C. Air injection tests were repeated following the heating and cooling cycle, and the results showed significant increases in bulk permeability ranging from 10 to 1830% along the borehole.
Date: October 1, 1991
Creator: Lee, K.H. & Ueng, Tzou-Shin
Partner: UNT Libraries Government Documents Department

A Study on the Tritium Behavior in the Rice Plant after a Short-Term Exposure of HTO

Description: In many Asian countries including Korea, rice is a very important food crop. Its grain is consumed by humans and its straw is used to feed animals. In Korea, there are four CANDU type reactors that release relatively large amounts of tritium into the environment. Since 1997, KAERI (Korea Atomic Energy Research Institute) has carried out the experimental studies to obtain domestic data on various parameters concerning the direct contamination of plant. In this study, the behavior of tritium in the rice plant is predicted and compared with the measurement performed at KAERI. Using the conceptual model of the soil-plant-atmosphere tritiated water transport system which was suggested by Charles E. Murphy, tritium concentrations in the soil and in leaves to time were derived. If the effect of tritium concentration in the soil is considered, the tritium concentration in leaves is described as a double exponential model. On the other hand if the tritium concentration in the soil is disregarded, the tritium concentration in leaves is described by a single exponential term as other models (e.g. Belot's or STAR-H3 model). Also concentration of organically bound tritium in the seed is predicted and compared with measurements. The results can be used to predict the tritium concentration in the rice plant at a field around the site and the ingestion dose following the release of tritium to the environment.
Date: February 26, 2002
Creator: Yook, D-S.; Lee, K. J. & Choi, Y-H.
Partner: UNT Libraries Government Documents Department

3D Thermal and Electrochemical Model for Spirally Wound Large Format Lithium-ion Batteries (Presentation)

Description: In many commercial cells, long tabs at both cell sides, leading to uniform potentials along the spiral direction of wound jelly rolls, are rarely seen because of their high manufacturing cost. More often, several metal strips are welded at discrete locations along both current collector foils. With this design, the difference of electrical potentials is easily built up along current collectors in the spiral direction. Hence, the design features of the tabs, such as number, location and size, can be crucial factors for spiral-shaped battery cells. This paper presents a Li-ion battery cell model having a 3-dimensional spiral mesh involving a wound jellyroll structure. Further results and analysis will be given regarding impacts of tab location, number, and size.
Date: October 14, 2010
Creator: Lee, K. J.; Kim, G. H. & Smith, K.
Partner: UNT Libraries Government Documents Department

Muon shielding calculations: heterogeneous passive and active shields, applicat�ons to experimental beams and areas

Description: With the advent of a new generation of high-energy and high-intensity proton accelerators such as the one being built at the National Accelerator Laboratory and the one proposed by CERN, the problem of shielding external proton targets, the secondary beams produced from these targets, and even the secondary targets in the experimental areas becomes quite a massive and expensive project. In addition to the massive hadron shielding required, the high-energy muons produced by the decay of pions and kaons add large amounts of shielding especially in the forward (beam) direction. Homogeneous shields can be designed with programs which have been discussed previously. They have developed a computer program which allows them to design heterogeneous shields with voids and/or magnetic fields. The heterogeneous shields without magnetic fields are called passive shields and those with magnetic fields are called active shields. Results of some of the studies made on the design of such shields are presented. Specific application to the design of shielding for a primary external proton beam target and for a specific experiment are discussed.
Date: January 1, 1971
Creator: Theriot, D.; Awschalom, M.; Lee, K. & /Fermilab
Partner: UNT Libraries Government Documents Department

Four-deep charge-time and pulse-width scaling discriminator for delay line MWPC's

Description: A discriminator has been developed for digitizing both intercepted total charge and location of electromagnetic shower and particle trajectories in multi- wire proportional chambers read by delay lines. Determination of shower trajectory is aided by video signal integration followed by centroid-locating discrimination. Calibrated run-down of the signal integrating capacitor gives the charge information above a given threshold level. The discriminator is designed to handle up to four shower-induced video signals per event by incorporating steering circuits within the module. Each video signal is examined for time over an adjustable threshold. Video pulses with separation of less than 20 nsec are treated as a single pulse. Counter-logic circuits indicate the number of video signals digitized. These signal processing circuits provide a first level of data sifting which otherwise must be carried out with additional discriminator channels and added complexity in data recognition.
Date: November 1, 1975
Creator: Lee, K.L.; Kirsten, F.A.; Grigorian, A. & Guiragossian, Z.G.T.
Partner: UNT Libraries Government Documents Department

High-frequency electric field measurement using a toroidal antenna

Description: In this paper the author describes an innovative method of measuring high-frequency electric fields using a toroid. For typical geophysical applications the new sensor will detect electric fields for a wide range of spectrum starting from 1.0 MHz. This window, in particular the lower frequency range between 1.0 to 100 MHz, has not been used for existing electromagnetic or radar systems to detect small objects in the upper few meters of the ground. Ground penetrating radar (GPR) can be used successfully in this depth range if the ground is resistive but most soils are, in fact, conductive (0.01 to 1.0 S/m) rendering GPR inefficient. Other factors controlling the resolution of GPR system for small objects is the spatial averaging inherent in the electric dipole antenna and the scattering caused by soil inhomogeneities of dimensions comparable to the wavelength (and antenna size). For maximum resolution it is desirable to use the highest frequencies but the scattering is large and target identification is poor. Time-varying magnetic fields induce an emf (voltage) in a toroid. The electric field at the center of the toroid is shown to be linearly related to this induced voltage. By measuring the voltage across a toroid one can easily and accurately determine the electric field. The new sensor will greatly simplify the cumbersome procedure involved with GPR measurements with its center frequency less than 100 MHz. The overall size of the toroidal sensor can be as small as a few inches. It is this size advantage that will not only allow easy fabrication and deployment of multi-component devices either on the surface or in a borehole, but it will render greatly improved resolution over conventional systems.
Date: January 1, 1997
Creator: Lee, K.H.
Partner: UNT Libraries Government Documents Department

Turbomachinery blade optimization using the Navier-Stokes equations

Description: A method is presented to perform aerodynamic design optimization of turbomachinery blades. The method couples a Navier-Stokes flow solver with a grid generator and numerical optimization algorithm to seek improved designs for transonic turbine blades. A fast and efficient multigrid, finite-volume flow solver provides accurate performance evaluations of potential designs. Design variables consist of smooth perturbations to the blade surface. A unique elliptic-hyperbolic grid generation method is used to regenerate a Navier-Stokes grid after perturbations have been added to the geometry. Designs are sought which improve a design objective while remaining within specified constraints. The method is demonstrated with two transonic turbine blades with different types and numbers of design variables.
Date: December 1, 1997
Creator: Chand, K. K. & Lee, K. D.
Partner: UNT Libraries Government Documents Department

Detonation spreading in fine TATBs

Description: A test has been devised that permits rapid evaluation of the detonation-spreading (or corner-turning) properties of detonations in insensitive high explosives. The test utilizes a copper witness plate as the medium to capture performance data. Dent depth and shape in the copper are used as quantitative measures of the detonation output and spreading behavior. The merits of the test are that it is easy to perform with no dynamic instrumentation, and the test requires only a few grams of experimental explosive materials.
Date: December 31, 1998
Creator: Kennedy, J.E.; Lee, K.Y.; Spontarelli, T. & Stine, J.R.
Partner: UNT Libraries Government Documents Department

Particle-beam approach to collective instabilities -- application to space-charge dominated beams

Description: Nonlinear dynamics deals with parametric resonances and di#11;usion. The phenomena are usually beam-intensity independent and rely on a particle Hamiltonian. Collective instabilities deal with beam coherent motion, where the Vlasov equation is frequently used in conjunction with a beam-intensity dependent Hamiltonian. We ad- dress the questions: Are the two descriptions the same? Are collective instabilities the results of encountering parametric resonances whose driving force is intensity depen- dent? We study here the example of a space-charge dominated beam governed by the Kapchinskij-Vladimirskij (K-V) envelope equation [1]. The stability and instability regions as functions of tune depression and envelope mismatch are compared in the two approaches. The study has been restricted to the simple example of a uniformly focusing channel.
Date: November 1, 1998
Creator: Lee, K.Y. Ng and S.Y.
Partner: UNT Libraries Government Documents Department

Electromagnetic method for analyzing the property of steel casing

Description: It has been shown that electromagnetic (EM) imaging, in particular in borehole applications, can be effective in characterizing and monitoring subsurface processes involved in improved oil recovery operations and production management. In this report the authors present an innovative EM method for extracting information about a steel casing in terms of its electrical conductivity, magnetic permeability, and the casing thickness. The method is based on accurate evaluation of magnetic fields near the transmitting loop in a steel-cased borehole, and the least squares inversion of thus measured data. The need to make measurements close to the source stems from the two related considerations. One reason is that by making measurements close to the transmitter one can keep the formation response from entering the measurement to a minimum. The other reason concerns with the practical consideration involved in fabricating a borehole tool. The measurement accuracy in terms of PPM to the primary field can best be achieved when the transmitter and receiver are close to each other. To facilitate this requirement one can consider a single loop acting as the source and the receiver operating in time domain, or a closely coupled frequency-domain system with the source-receiver separation of just a few inches apart. Results are discussed.
Date: February 1, 1998
Creator: Lee, K.H.; Kim, H.J. & Song, Y.
Partner: UNT Libraries Government Documents Department