The Gunite and Associated Tanks Remediation Project Tank Waste Retrieval Performance and Lessons Learned, vol. 1 [of 2] (open access)

The Gunite and Associated Tanks Remediation Project Tank Waste Retrieval Performance and Lessons Learned, vol. 1 [of 2]

The Gunite and Associated Tanks (GAAT) Remediation Project was the first of its kind performed in the United States. Robotics and remotely operated equipment were used to successfully transfer almost 94,000 gal of remote-handled transuranic sludge containing over 81,000 Ci of radioactive contamination from nine large underground storage tanks at the Oak Ridge National Laboratory (ORNL). The sludge was transferred with over 439,000 gal of radioactive waste supernatant and {approx}420,500 gal of fresh water that was used in sluicing operations. The GAATs are located in a high-traffic area of ORNL near a main thoroughfare. A phased and integrated approach to waste retrieval operations was used for the GAAT Remediation Project. The project promoted safety by obtaining experience from low-risk operations in the North Tank Farm before moving to higher-risk operations in the South Tank Farm. This approach allowed project personnel to become familiar with the tanks and waste, as well as the equipment, processes, procedures, and operations required to perform successful waste retrieval. By using an integrated approach to tank waste retrieval and tank waste management, the project was completed years ahead of the original baseline schedule, which resulted in avoiding millions of dollars in associated costs. This report is …
Date: October 7, 2003
Creator: Lewis, BE
Object Type: Report
System: The UNT Digital Library
SNAP Satellite Focal Plane Development (open access)

SNAP Satellite Focal Plane Development

The proposed SuperNova/Acceleration Probe (SNAP) mission will have a two-meter class telescope delivering diffraction-limited images to an instrumented 0.7 square degree field in the visible and near-infrared wavelength regime. The requirements for the instrument suite and the present configuration of the focal plane concept are presented. A two year R&D phase, largely supported by the Department of Energy, is just beginning. We describe the development activities that are taking place to advance our preparedness for mission proposal in the areas of detectors and electronics.
Date: July 7, 2003
Creator: Bebek, C.; Akerlof, C.; Aldering, G.; Amanullah, R.; Astier, P.; Baltay, C. et al.
Object Type: Article
System: The UNT Digital Library
EOSN: A TOUGH2 module for noble gases (open access)

EOSN: A TOUGH2 module for noble gases

We developed a new fluid property module for TOUGH2, called EOSN, to simulate transport of noble gases in the subsurface. Currently, users may select any of five different noble gases as well as CO2, two at a time. For the three gas components (air and two user-specified noble gases) in EOSN, the Henry's coefficients and the diffusivities in the gas phase are no longer assumed constants, but are temperature dependent. We used the Crovetto et al. (1982) model to estimate Henry's coefficients, and the Reid et al. (1987) correlations to calculate gas phase diffusivities. The new module requires users to provide names of the selected noble gases, which properties are provided internally. There are options for users to specify any (non-zero) molecular weights and half-lives for the gas components. We provide two examples to show applications of TOUGH2IEOSN. While temperature effects are relatively insignificant for one example problem where advection is dominant, they cause almost an order of magnitude difference for the other case where diffusion becomes a dominant process and temperature variations are relatively large. It appears that thermodynamic effects on gas diffusivities and Henry's coefficients can be important for low-permeability porous media and zones with large temperature variations.
Date: March 7, 2003
Creator: Shan, Chao & Pruess, Karsten
Object Type: Report
System: The UNT Digital Library
Oxygen Transport Ceramic Membranes (open access)

Oxygen Transport Ceramic Membranes

In the present quarter, experiments are presented on ceramic/metal interactions of Zirconia/ Ni-B-Si system and with a thin Ti coating deposited on zirconia surface. Existing facilities were modified for evaluation of environmental assisted slow crack growth and creep in flexural mode. Processing of perovskites of LSC, LSF and LSCF composition were continued for evaluation of mechanical properties as a function of environment. These studies in parallel to those on the LSFCO composition is expect to yield important information on questions such as the role of cation segregation and the stability of the perovskite structure on crack initiation vs. crack growth. Studies have been continued on the La{sub 1-x}Sr{sub x}FeO{sub 3-d} composition using neutron diffraction and TGA studies. A transition from p-type to n-type of conductor was observed at relative low pO{sub 2}, at which the majority carriers changed from the holes to electrons because of the valence state decreases in Fe due to the further loss of oxygen. Investigation on the thermodynamic properties of the membrane materials are continued to develop a complete model for the membrane transport. Data obtained at 850 C show that the stoichiometry in La{sub 0.2}Sr{sub 0.8}Fe{sub 0.8}Cr{sub 0.2}O{sub 3-x} vary from {approx}2.85 to 2.6 over …
Date: August 7, 2003
Creator: Bandopadhyay, S. & Nagabhushana, N.
Object Type: Report
System: The UNT Digital Library
The Gunite and Associated Tanks Remediation Project Tank Waste Retrieval Performance and Lessons Learned, vol. 2 [of 2] (open access)

The Gunite and Associated Tanks Remediation Project Tank Waste Retrieval Performance and Lessons Learned, vol. 2 [of 2]

The Gunite and Associated Tanks (GAAT) Remediation Project was the first of its kind performed in the United States. Robotics and remotely operated equipment were used to successfully transfer almost 94,000 gal of remote-handled transuranic sludge containing over 81,000 Ci of radioactive contamination from nine large underground storage tanks at the Oak Ridge National Laboratory (ORNL). The sludge was transferred with over 439,000 gal of radioactive waste supernatant and {approx}420,500 gal of fresh water that was used in sluicing operations. The GAATs are located in a high-traffic area of ORNL near a main thoroughfare. Volume 1 provides information on the various phases of the project and describes the types of equipment used. Volume 1 also discusses the tank waste retrieval performance and the lessons learned during the remediation effort. Volume 2 consists of the following appendixes, which are referenced in Vol. 1: A--Background Information for the Gunite and Associated Tanks Operable Unit; B--Annotated Bibliography; C--GAAT Equipment Matrix; D--Comprehensive Listing of the Sample Analysis Data from the GAAT Remediation Project; and E--Vendor List for the GAAT Remediation Project. The remediation of the GAATs was completed {approx}5.5 years ahead of schedule and {approx}$120,435K below the cost estimated in the Remedial Investigation/Feasibility Study …
Date: October 7, 2003
Creator: Lewis, BE
Object Type: Report
System: The UNT Digital Library
A High-Throughput Microenvironment for Single-Cell Operations (open access)

A High-Throughput Microenvironment for Single-Cell Operations

This project was conducted as a feasibility study, in preparation for including this work in the forthcoming ''Instrumented Cell'' (IC) Strategic Initiative. The goal of the IC is to study individual cells; the goal of this feasibility study was to determine the best method for isolating large numbers of individual cells in a way that facilitates various types of environmental changes and intracellular measurements. We have the capability to do this with one cell, and sought to expand the number of cells that we could study simultaneously. Our specific goal for this feasibility study was to discover a way to isolate individual cells, and impale them on a nanopipette. This would enable samples to be introduced into and removed from a cell.
Date: January 7, 2003
Creator: Christian, A. T.; Buckley, P. & Miles, R. R.
Object Type: Report
System: The UNT Digital Library
TFMC Tcs Data: How Do We Compare Conductor Performance to the Strand and What Conclusions for ITER We May Draw (open access)

TFMC Tcs Data: How Do We Compare Conductor Performance to the Strand and What Conclusions for ITER We May Draw

This memo is to assess the TFMC test results and compare it with the strand performance. The TFMC is not an ideal object for studying performance of the CICC in a sense that the instrumentation priority was considered secondary to reliability and therefore a lot of assumptions and modeling need to be made to make the comparison against the LMI strand possible. To compare the CICC performance to strand we need to know at least current in the strands, magnetic field and electric field distribution along the strands, temperature profile and strain distribution. In the TFMC we have much less uniform magnetic field and less determined temperature than in the CSMC Inserts, so role of modeling is greater. A code M&M developed by Polito team (R. Zanino and L. Savoldi Richard) evaluates the temperature profile in the conductor. It includes heat transfer in joints, self-heating, heat transfer to the radial plates. From their model it follows [1] that the radial plates do not affect significantly the temperature in the conductor near the area with the peak magnetic field, which is 3-5 m away from the conductor entrance inside the TFMC winding pack. Unfortunately, there are no sensors in between the …
Date: January 7, 2003
Creator: Martovetsky, N.
Object Type: Report
System: The UNT Digital Library
Inversion of Synthetic Aperture Radar Interferograms for Sources of Production-Related Subsidence at the Dixie Valley Geothermal Field (open access)

Inversion of Synthetic Aperture Radar Interferograms for Sources of Production-Related Subsidence at the Dixie Valley Geothermal Field

We used synthetic aperture radar interferograms to image ground subsidence that occurred over the Dixie Valley geothermal field during different time intervals between 1992 and 1997. Linear elastic inversion of the subsidence that occurred between April, 1996 and March, 1997 revealed that the dominant sources of deformation during this time period were large changes in fluid volumes at shallow depths within the valley fill above the reservoir. The distributions of subsidence and subsurface volume change support a model in which reduction in pressure and volume of hot water discharging into the valley fill from localized upflow along the Stillwater range frontal fault is caused by drawdown within the upflow zone resulting from geothermal production. Our results also suggest that an additional source of fluid volume reduction in the shallow valley fill might be similar drawdown within piedmont fault zones. Shallow groundwater flow in the vicinity of the field appears to be controlled on the NW by a mapped fault and to the SW by a lineament of as yet unknown origin.
Date: February 7, 2003
Creator: Foxall, W & Vasco, D
Object Type: Article
System: The UNT Digital Library
New Approaches to Quantum Computing Using Nuclear Magnetic Resonance Spectroscopy (open access)

New Approaches to Quantum Computing Using Nuclear Magnetic Resonance Spectroscopy

The power of a quantum computer (QC) relies on the fundamental concept of the superposition in quantum mechanics and thus allowing an inherent large-scale parallelization of computation. In a QC, binary information embodied in a quantum system, such as spin degrees of freedom of a spin-1/2 particle forms the qubits (quantum mechanical bits), over which appropriate logical gates perform the computation. In classical computers, the basic unit of information is the bit, which can take a value of either 0 or 1. Bits are connected together by logic gates to form logic circuits to implement complex logical operations. The expansion of modern computers has been driven by the developments of faster, smaller and cheaper logic gates. As the size of the logic gates become smaller toward the level of atomic dimensions, the performance of such a system is no longer considered classical but is rather governed by quantum mechanics. Quantum computers offer the potentially superior prospect of solving computational problems that are intractable to classical computers such as efficient database searches and cryptography. A variety of algorithms have been developed recently, most notably Shor's algorithm for factorizing long numbers into prime factors in polynomial time and Grover's quantum search algorithm. …
Date: February 7, 2003
Creator: Colvin, M. & Krishnan, V. V.
Object Type: Report
System: The UNT Digital Library
Biological Review of the Hanford Solid Waste EIS - Borrow Area C (600 Area), Stockpile and Conveyance Road Area (600 Area), Environmental Restoration Disposal Facility (ERDF) (600 Area), Central Waste Complex (CWC) Expansion (200 West), 218-W-5 Expansion Area (200 West), New Waste Processing Facility (200 West)...ECR No. 2002-600-012b (open access)

Biological Review of the Hanford Solid Waste EIS - Borrow Area C (600 Area), Stockpile and Conveyance Road Area (600 Area), Environmental Restoration Disposal Facility (ERDF) (600 Area), Central Waste Complex (CWC) Expansion (200 West), 218-W-5 Expansion Area (200 West), New Waste Processing Facility (200 West)...ECR No. 2002-600-012b

This letter report is a supplement to the letter reports submitted previously under ECRs No. 2002-600-012 (Borrow Area C) and No. 2002-600-012a (CWC expansion). This letter report covers all areas that may be subject to surface disturbance under Alternative Groups A, B, C, D1, D2, D3, E1, E2, E3, and the No Action Alternative of the Hanford Solid Waste Environmental Impact Statement (HSW EIS), except for the following Low-Level Burial Grounds (LLBGs). The LLBGs proposed for use in the HSW EIS that are not subject of this letter report (218-W-3A, 218-W-3AE, 218-W 4B, 218-W-5, the developed portion of 218-W-4C, and the eastern half [except the northeastern corner] of 218-W-6 in the 200 West Area; and 218-E-10 and 218-E-12B in the 200 East Area) are surveyed annually. Annual letter reports concerning these are currently sent to Mr. Brett M. Barnes of Fluor Hanford, Inc. For the areas of surface disturbance described herein we provide a summary of field survey methods, survey results, and considerations and recommendations based on these results.
Date: April 7, 2003
Creator: Sackschewsky, Michael R.
Object Type: Report
System: The UNT Digital Library
Simulating Fine-Scale Atmospheric Processes: A New Core Capability and its Application to Predicting Wildfire Behavior (open access)

Simulating Fine-Scale Atmospheric Processes: A New Core Capability and its Application to Predicting Wildfire Behavior

This LDRD project consisted of the development, testing, and prototype application of a new capability to couple atmospheric models of different spatial and temporal scales with a state-of-the-science vegetation-fuel combustion model and a GIs-based analysis system. The research addressed the complex, multi-scale interactions of atmospheric processes, combustion, and vegetative fuel conditions, using a suite of models to simulate their impact on wildfire behavior in areas of complex terrain. During the course of the project, we made substantial progress toward the implementation of a world-class modeling system that could be used as a tool for wildfire risk assessment, wildfire consequence analysis, wildfire suppression planning, fuels management, firefighter training, and public fire-safety education. With one additional year of funding we would have been able conduct combined modeling and field experiments to evaluate the models capability to predict the behavior of prescribed burns before they are ignited. Because of its investment in this LDRD project, LLNL is very close to having a new core capability--likely the world's most generally applicable, most scientifically sound, and most respected wildfire simulation system.
Date: February 7, 2003
Creator: Bradley, M M; Leach, M J; Molenkamp, C R; Hall, C H; Wilder, L & Neher, L A
Object Type: Report
System: The UNT Digital Library
Design of a 50 TW/20 J chirped-Pulse Amplification Laser for High-Energy-Density Plasma Physics Experiments at the Nevada Terawatt Facility of the University of Nevada (open access)

Design of a 50 TW/20 J chirped-Pulse Amplification Laser for High-Energy-Density Plasma Physics Experiments at the Nevada Terawatt Facility of the University of Nevada

We have developed a conceptual design for a 50 TW/20 J short-pulse laser for performing high-energy-density plasma physics experiments at the Nevada Terawatt Facility of the University of Nevada, Reno. The purpose of the laser is to develop proton and x-ray radiography techniques, to use these techniques to study z-pinch plasmas, and to study deposition of intense laser energy into both magnetized and unmagnetized plasmas. Our design uses a commercial diode-pumped Nd:glass oscillator to generate 3-nJ. 200-fs mode-locked pulses at 1059 m. An all-reflective grating stretcher increases pulse duration to 1.1 ns. A two-stage chirped-pulse optical parametric amplifier (OPCPA) using BBO crystals boosts pulse energy to 12 mJ. A chain using mixed silicate-phosphate Nd:glass increases pulse energy to 85 J while narrowing bandwidth to 7.4 nm (FWHM). About 50 J is split off to the laser target chamber to generate plasma while the remaining energy is directed to a roof-mirror pulse compressor, where two 21 cm x 42 cm gold gratings recompress pulses to {approx}350 fs. A 30-cm-focal-length off-axis parabolic reflector (OAP) focuses {approx}20 J onto target, producing an irradiance of 10{sup 19} W/cm{sup 2} in a 10-{micro}m-diameter spot. This paper describes planned plasma experiments, system performance requirements, the laser …
Date: September 7, 2003
Creator: Erlandson, A. C.; Astanovitskiy, A.; Batie, S.; Bauer, B.; Bayramian, A.; Caird, J. A. et al.
Object Type: Article
System: The UNT Digital Library
Novel Application of Fiber Optic Sensor for Characterizing Real-Time Contaminant Transport in Rapid Storm Runoff (open access)

Novel Application of Fiber Optic Sensor for Characterizing Real-Time Contaminant Transport in Rapid Storm Runoff

None
Date: February 7, 2003
Creator: Campbell, C G; Richards, J; Zavarin, M; Stratton, P; Coty, J & Laycak, D
Object Type: Report
System: The UNT Digital Library
Outlook: The Next Twenty Years (open access)

Outlook: The Next Twenty Years

I present an outlook for the next twenty years in particle physics. I start with the big questions in our field, broken down into four categories: horizontal, vertical, heaven, and hell. Then I discuss how we attack the bigquestions in each category during the next twenty years. I argue for a synergy between many different approaches taken in our field.
Date: December 7, 2003
Creator: Murayama, Hitoshi
Object Type: Article
System: The UNT Digital Library
Further studies of electron avalanche gain in liquid argon (open access)

Further studies of electron avalanche gain in liquid argon

Previously we showed how small admixtures of xenon (Xe) stabilize electron avalanches in liquid Argon (LAr). In the present work, we have measured the positive charge carrier mobility in LAr with small admixtures of Xe to be 6.4 x 10{sup -3} cm{sup 2}/Vsec, in approximate agreement with the mobility measured in pure LAr, and consistent with holes as charge carriers. We have measured the concentration of Xe actually dissolved in the liquid and compared the results with expectations based on the amount of Xe gas added to the LAr. We also have tested LAr doped with krypton to investigate the mechanism of avalanche stabilization.
Date: March 7, 2003
Creator: Kim, J. G.; Dardin, S. M.; Kadel, R. W.; Kadyk, J. A.; Jackson, K. H.; Peskov, V. et al.
Object Type: Article
System: The UNT Digital Library
High resolution angle-resolved photoemission study of hightemperature superconductors: charge-ordering, bilayer splitting andelectron-phonon coupling (open access)

High resolution angle-resolved photoemission study of hightemperature superconductors: charge-ordering, bilayer splitting andelectron-phonon coupling

The latest development of angle-resolved photoemission spectroscopy (ARPES) technique has seen extremely high energy resolution and momentum resolution, as well as multiple angle detection. These advancements have led to new findings through efficient Fermi surface mapping, fine electronic structure resolving, and direct determination of electron self-energy. In this paper, we will highlight some recent high resolution ARPES work on high temperature superconductors. These include: (1) charge-ordering and evolution of electronic structure with doping; (2) bilayer splitting and Fermi surface topology of Bi2212; and (3) strong electron phonon coupling and electron electron interaction in high temperature superconductors.
Date: July 7, 2003
Creator: Zhou, Xingjiang; Hussain, Zahid & Shen, Zhi-xun
Object Type: Article
System: The UNT Digital Library
An Improved Calibration Method for Hydrazine Monitors for the United States Air Force (open access)

An Improved Calibration Method for Hydrazine Monitors for the United States Air Force

This report documents the results of Phase 1 of the ''Air Force Hydrazine Detector Characterization and Calibration Project''. A method for calibrating model MDA 7100 hydrazine detectors in the United States Air Force (AF) inventory has been developed. The calibration system consists of a Kintek 491 reference gas generation system, a humidifier/mixer system which combines the dry reference hydrazine gas with humidified diluent or carrier gas to generate the required humidified reference for calibrations, and a gas sampling interface. The Kintek reference gas generation system itself is periodically calibrated using an ORNL-constructed coulometric titration system to verify the hydrazine concentration of the sample atmosphere in the interface module. The Kintek reference gas is then used to calibrate the hydrazine monitors. Thus, coulometric titration is only used to periodically assess the performance of the Kintek reference gas generation system, and is not required for hydrazine monitor calibrations. One advantage of using coulometric titration for verifying the concentration of the reference gas is that it is a primary standard (if used for simple solutions), thereby guaranteeing, in principle, that measurements will be traceable to SI units (i.e., to the mole). The effect of humidity of the reference gas was characterized by using …
Date: July 7, 2003
Creator: Korsah, K
Object Type: Report
System: The UNT Digital Library
Energy Production from Zoo Animal Wastes (open access)

Energy Production from Zoo Animal Wastes

Elephant and rhinoceros dung was used to investigate the feasibility of generating methane from the dung. The Knoxville Zoo produces 30 cubic yards (23 m{sup 3}) of herbivore dung per week and cost of disposal of this dung is $105/week. The majority of this dung originates from the Zoo's elephant and rhinoceros population. The estimated weight of the dung is 20 metric tons per week and the methane production potential determined in experiments was 0.033 L biogas/g dung (0.020 L CH{sub 4}/g dung), and the digestion of elephant dung was enhanced by the addition of ammonium nitrogen. Digestion was better overall at 37 C when compared to digestion at 50 C. Based on the amount of dung generated at the Knoxville Zoo, it is estimated that two standard garden grills could be operated 24 h per day using the gas from a digester treating 20 metric ton herbivore dung per week.
Date: April 7, 2003
Creator: Klasson, KT
Object Type: Report
System: The UNT Digital Library
Interprocessor communication with limited memory (open access)

Interprocessor communication with limited memory

Many parallel applications require periodic redistribution of workloads and associated data. In a distributed memory computer, this redistribution can be difficult if limited memory is available for receiving messages. We propose a model for optimizing the exchange of messages under such circumstances which we call the minimum phase remapping problem. We first show that the problem is NP-Complete, and then analyze several methodologies for addressing it. First, we show how the problem can be phrased as an instance of multi-commodity flow. Next, we study a continuous approximation to the problem. We show that this continuous approximation has a solution which requires at most two more phases than the optimal discrete solution, but the question of how to consistently obtain a good discrete solution from the continuous problem remains open. We also devise simple and practical approximation algorithm for the problem with a bound of 1.5 times the optimal number of phases. We also present an empirical study of variations of our algorithms which indicate that our approaches are quite practical.
Date: May 7, 2003
Creator: Pinar, Ali & Hendrickson, Bruce
Object Type: Article
System: The UNT Digital Library
Prediction of water seepage into a geologic repository for high-level radioactive waste (open access)

Prediction of water seepage into a geologic repository for high-level radioactive waste

Predicting the amount of water that may seep into waste emplacement drifts is important for assessing the performance of the proposed geologic repository for high-level radioactive waste at Yucca Mountain, Nevada. The repository would be located in thick, partially saturated fractured tuff that will be heated to above-boiling temperatures as a result of heat generation from the decay of nuclear waste. Since infiltrating water will be subject to vigorous boiling for a significant time period, the superheated rock zone (i.e., rock temperature above the boiling point of water) can form an effective vaporization barrier that reduces the possibility of water arrival at emplacement drifts. In this paper, we analyze the behavior of episodic preferential flow events that penetrate the hot fractured rock, evaluate the impact of such flow behavior on the effectiveness of the vaporization barrier, and discuss the implications for the performance assessment of the repository. A semi-analytical solution is utilized to determine the complex flow processes in the hot rock environment. The solution is applied at several discrete times after emplacement, covering the time period of strongly elevated temperatures at Yucca Mountain.
Date: July 7, 2003
Creator: Birkholzer, Jens; Mukhophadhyay, Sumit & Tsang, Yvonne
Object Type: Article
System: The UNT Digital Library
Computational economy improvements in PRISM (open access)

Computational economy improvements in PRISM

None
Date: May 7, 2003
Creator: Tonse, Shaheen R.; Moriarty, Nigel W.; Frenklach, Michael & Brown, Nancy J.
Object Type: Article
System: The UNT Digital Library
Performance evaluation of cleanroom environmental systems (open access)

Performance evaluation of cleanroom environmental systems

This paper presents in-situ measurement results for energy and environmental performance of thirteen cleanroom systems located in the USA, including key metrics for evaluating cleanroom air system performance and overall electric power intensity. Comparisons with the IEST Recommended Practice (IEST-RP-CC012.1) are made to examine the performance of cleanroom air systems. Based upon the results, the paper discusses likely opportunities for improving cleanroom energy efficiency while maintaining effective contamination control. The paper concludes that there are wide variations in energy performance of cleanroom environmental systems, and that performance benchmarking can serve as a vehicle to identify energy efficient cleanroom design practices and to highlight important issues in cleanroom operation and maintenance.
Date: July 7, 2003
Creator: Xu, Tengfang
Object Type: Article
System: The UNT Digital Library
An introduction to using software tools for automatic differentiation. (open access)

An introduction to using software tools for automatic differentiation.

The authors give a gentle introduction to using various software tools for Automatic Differentiation (AD). Ready-to-use examples are discussed and links to further information are presented. The target audience includes all those who are looking for a straight-forward way to get started using the available AD technology. The document is supposed to be dynamic in the sense that its content will be kept up-to-date as the AD software covered is evolving.
Date: October 7, 2003
Creator: Naumann, U. & Walther, A.
Object Type: Report
System: The UNT Digital Library
SYNTHESIS AND CHARACTERIZATION OF NEW INTERMETALLIC COMPOUNDS (open access)

SYNTHESIS AND CHARACTERIZATION OF NEW INTERMETALLIC COMPOUNDS

This six-month work is focused mainly on the properties of novel magnetic intermetallics. In the first project, we synthesized several 2:17 intermetallic compounds, namely Nd{sub 2}Fe{sub 15}Si{sub 2}, Nd{sub 2}Fe{sub 15}Al{sub 2}2, Nd{sub 2}Fe{sub 15}SiAl and Nd{sub 2}Fe{sub 15}SiMn, as well as several 1:12 intermetallic compounds, such as NdFe{sub 10}Si{sub 2}, NdFe{sub 10}Al{sub 2}, NdFe{sub 10}SiAl and NdFe{sub 10}MnAl. In the second project, seven compositions of Nd{sub x}Fe{sub 100-x-y}B{sub y} ribbons were prepared by a melt spinning method with Nd and B content increasing from 7.3 and 3.6 to 11 and 6, respectively. The alloys were annealed under optimized conditions to obtain a composite material consisting of the hard magnetic Nd{sub 2}Fe{sub 14}B and soft magnetic {alpha}-Fe phases, typical of a spring magnet structure. In the third project, intermetallic compounds of the type Zr{sub 1}Cr{sub 1}Fe{sub 1}T{sub 0.8} with T=Al, Co and Fe were subjected to hydrogenation. In the fourth project, we performed three crucial experiments. In the first experiment, we subjected a mixture of Fe{sub 3}O{sub 4} and Fe(80-20 wt%) to mechanochemical activation by high-energy ball milling, for time periods ranging from 0.5 to 14 hours. In the second experiment, we ball-milled Fe{sub 3}O{sub 4}:Co{sup 2+} (x=0.1) for time …
Date: May 7, 2003
Creator: Sorescu, Professor Monica
Object Type: Report
System: The UNT Digital Library