The successful separation of pyrite from coal by flotation is dependent to a large extent upon the selectivity of the process, and the use of a pyrite depressant is one of the most important and cost-effective techniques for achieving this. This report evaluates the effects of three factors on the floatability of pyrite. These are (1) the superficial oxidation of pyrite, (2) the contamination of pyrite surfaces by carbonaceous matter, and (3) pulp redox potentials. XPS (x-ray photoelectron spectroscopy) and IR spectrometry have been used to identify surface reaction products. Microflotation, laboratory-scale conventional flotation and microbubble column flotation were used to quantify the effects of these factors. It was found that low (reducing) pulp potentials are effective depressants of pyrite (more so for fresh, unoxidized samples than for oxidized samples), whilst at the same time do not materially affect coal flotation.

To better understand the surface chemical properties of coal and mineral pyrite, studies on the effect of flotation surfactants (frother and kerosene) on the degree of hydrophobicity have been conducted. The presence of either frother or kerosene enhanced the flotability of coal and mineral pyrite with a corresponding decrease in induction time over the pH range examined. Scanning electron microscopy (SEM) results indicate a correlation exists between the sample surface morphology and crystal structure and the observed hydrophobicity. As a result of the data obtained from the surface characterization studies, controlled surface oxidation was investigated as a possible pyrite rejection scheme in microbubble column flotation.

The holographic stressmeter is an instrument which has been developed at Caltech to allow determination of the complete stress tensor from in situ borehole measurements. The stressmeter uses double-exposure holographic interferometry to record the displacements induced by the drilling of a small sidehole into the borehole wall. The local stresses, which are the result of the far-field stresses, concentrated at the borehole, cause deformation of the surface of the borehole wall in the vicinity of the sidehole. The first part of this study uses a thin infinite elastic plate subjected to plane stress at infinity to model the displacements at the borehole wall. However, the existence of some holograms which were difficult to model closely led us to examine the validity of this model. In order to investigate the problem further, we performed a two-dimensional finite element analysis for an elastic box with a terminated hole. We varied the dimensions of the hole to see what effect the radius and depth of the hole might have on the displacements. The plate model predicts that the depth of the hole should have no effect on the horizontal components of displacement, but the finite element results show that the magnitude of both …

This research project proposes to develop novel new approaches of improving the radioimmunodetection and radioimmunotherapy of malignancies by augmenting retention of radioimmunoconjugates by tumor cells. The approaches shown to be effective in these laboratory experiments will subsequently be incorporated into out ongoing clinical trials in patients. Specific project objectives include: to study the rates of endocytosis, intracellular routing, and metabolic degradation of radiolabeled monoclonal antibodies targeting tumor-associated antigens on human leukemia and lymphoma cells; To examine the effects of lysosomotropic amines (e.g. chloroquine, amantadine), carboxylic ionophores (monensin, nigericin), and thioamides (propylthiouracil), on the retention of radiolabeled MoAbs by tumor cells; to examine the impact of newer radioiodination techniques (tyramine cellobiose, paraiodobenzoyl) on the metabolic degradation of radioiodinated antibodies; to compare the endocytosis, intracellular routing, and degradation of radioimmunoconjugates prepared with different radionuclides ({sup 131}Iodine, {sup 111}Indium, {sup 90}Yttrium, {sup 99m}Technetium, {sup 186}Rhenium); and to examine the utility of radioimmunoconjugates targeting oncogene products for the radioimmunotherapy and radioimmunoscintigraphy of cancer.

One of the most difficult separations in minerals processing involves the differential flotation of pyrite and coal. Under practical flotation conditions, they are both hydrophobic and no cost-effective method has been developed to efficiently reject the pyrite. The problem arises from inherent floatability of coal and pyrite. Coal is naturally hydrophobic and remains so under practical flotation. Although pyrite is believed to be naturally hydrophilic under practical flotation conditions it undergoes a relatively rapid incipient oxidation reaction that causes self-induced'' flotation. The oxidation product responsible for self-induced'' flotation is believed to be a metal polysulfide, excess sulfur in the lattice, or in some cases elemental sulfur. It is believed that if incipient oxidation of pyrite could be prevented, good pyrite rejection could be obtained. In order to gain a better understanding of how pyrite oxidizes, a new method of preparing fresh, unoxidized pyrite surfaces and a new method of studying pyrite oxidation have been developed this reporting period.

The long-range objective of this research program is the development of more efficacious technetium-99m radiopharmaceuticals for use as imaging agents in diagnostic nuclear medicine. We seek to isolate and develop distinct site imaging agents, each of which has properties optimized to provide diagnostic information concerning a given pathological condition. The specific objectives during the period (9/1/89 to 8/31/92) include: (1) Development of strategies for improving yields of specific Tc-diphosphonate complexes with optimum imaging properties; (2) Development of electrodes for rapid in situ electrochemical generation of skeletal imaging agents; (3) Development of electrochemical sensors for {Tc} and Re imaging agents; (4) Characterization of stable {Tc}- and Re-diphosphonate complexes obtainable in high yield by structural studies with techniques such as NMR, EXAFS, and Raman spectroscopy; (5) Development of improved separation techniques for the characterization of diphosphonate skeletal imaging agents; (6) Evaluation of the effect of the biological milieu on {Tc}-diphosphonate complexes; and (7) Electrochemical studies of technetium and rhenium complexes synthesized by Professor Deutsch's research group for heart and brain imaging.

Results from modeling of transformation toughening in brittle materials using a discrete micromechanical model are presented. The material is represented as a two-dimensional triangular array of nodes connected by elastic springs. Microstructural effects are included by varying the spring parameters for the bulk, grain boundaries, and transforming particles. Using the width of the damage zone and the effective compliance (after the initial creation of the damage zone) as measures of fracture toughness, we find that there is a strong dependence of toughness on the amount, size, and shape of the transforming particles, with the maximum toughness achieved with the higher amounts of the larger particles.

The two-hit resolution of a silicon drift chamber is measured using a pulsed Nd:Yag laser and a time digitizer readout. The data is analyzed by forming the covariance matrix in time samples, and transforming to a matrix in amplitude and time variation of each of the two hits. The resolution of the two-hit separation is found to be better than 25 microns with a drift field of 530 V/cm and a separation of more than 500 microns, with the resolution increasing to 50 microns as the separation nears 500 microns. Results are also presented for multiply ionizing tracks, showing a great improvement over single minimum ionizing. 8 refs.

I have investigated the effect of scattering in the rock overburden on the position and direction of atmospheric muons as observed at the Soudan 2 detector relative to the surface. The dominant contributions to the fluctuations in those observables arise from multiple Coulomb scattering and delta ray production. The contribution of the other energy loss mechanisms, bremsstrahlung, pair production and nuclear interactions, is small, with slowly increasing importance at very large deviations from the means of the distributions.

Recent studies of nuclear mass models show that it is essential to account for the Coulomb redistribution energy when calculating the nuclear potential energy in the heavy-element region. Results obtained by use of a mass model that includes Coulomb redistribution effects on analyzed. Q values of {alpha} and {beta} decay are calculated. Half-lives for {alpha} decay are estimated by use of the Viola-Seaborg systematics. For EC, {beta}{sup +} decay and {beta}{sup {minus}} decay, half-lives are calculated in a microscopic QRPA model. Calculated single-particle level structures in the heavy-element regions are presented. These indicate possible regions of isomers that would be unusually stable with respect to spontaneous fission and {alpha} decay. Finally, we discuss the implications of earlier extensive work on fission properties of nuclei in this region.

The propagation of a laser beam through atmospheric turbulence can, under many circumstances, be compensated to near diffraction limited levels, by use of an adaptive optics system. In the ideal case, a beacon light source is generated at the aimpoint. This light traverses through the turbulent path back to the aperture. The distribution of phase perturbations in the aperture plane is sensed, and the reverse of this phase is applied to the outgoing beam. When the turbulent path is long (i.e. a few hundred kilometers), and the effective wind speed is high (such as in the case when the laser is based on a plane, with airspeeds around 200 m/s), the performance of the adaptive optics system can be significantly degraded due to the time delay from when the beacon samples the turbulence, until the beam propagates through the turbulence. This effect has not been treated in the past, because for astronomical applications, the time delays due to the round trip of light are too short (tens of microseconds) to cause problems. This paper presents an analysis of the anisoplanatic effect of the round trip time of light. A formulation of the phase variance has been constructed for this effect. …

The objective is to develop and test various integrated solar heating, cooling and domestic hot water systems, and to evaluate their performance. Systems composed of new, as well as previously tested, components are carefully integrated so that effects of new components on system performance can be clearly delineated. The SEAL-DOE program includes six tasks which have received funding for the 1991--92 fifteen-month period. These include: (1) a project employing isothermal operation of air and liquid solar space heating systems; (2) a project to build and test several generic solar water heaters; (3) a project that will evaluate advanced solar domestic hot water components and concepts and integrate them into solar domestic hot water systems; (4) a liquid desiccant cooling system development project; (5) a project that will perform system modeling and analysis work on solid desiccant cooling systems research; and (6) a management task. The objectives and progress in each task are described in this report.

The objective of this project is to investigate three possible routes to the formation of ethers, in particular methyl tert-butyl (MTBE), during slurry phase Fischer-Tropsch reaction. The three reaction schemes to be investigated are: addition of i-butylene during the formation of methanol and/or higher alcohols directly from CO and H[sub 2] during slurry-phase Fischer-Tropsch; addition of i-butylene to FT liquid products including alcohols in a slurry-phase reactor containing an MTBE or other acid catalyst; and addition of methanol to slurry phase FT synthesis making iso-olefins. During the seventh quarter we continued the shake down experiments for the SBCR and conducted an initial aborted run. We have also re-started experiments on Scheme 1, i.e., the addition of iso-butylene during CO hydrogenation. Using a dual bed arrangement, we have demonstrated the synthesis of MTBE from syngas and iso-butylene.

The coke plant at the Sparrows Point Plant consist of three coke oven batteries and two coal chemical plants. The by-product coke oven gas (COG) consists primarily of hydrogen, methane, carbon monoxide, nitrogen and contaminants consisting of tars, light oils (benzene, toluene, and xylene) hydrogen sulfide, ammonia, water vapor and other hydrocarbons. This raw coke oven gas needs to be cleaned of most of its contaminants before it can be used as a fuel at other operations at the Sparrows Point Plant. In response to environmental concerns, BSC decided to replace much of the existing coke oven gas treatment facilities in the two coal chemical Plants (A and B) with a group of technologies consisting of: Secondary Cooling of the Coke oven Gas; Hydrogen Sulfide Removal; Ammonia Removal; Deacification of Acid Gases Removed; Ammonia Distillation and Destruction; and, Sulfur Recovery. This combination of technologies will replace the existing ammonia removal system, the final coolers, hydrogen sulfide removal system and the sulfur recovery system. The existing wastewater treatment, tar recovery and one of the three light oil recovery systems will continue to be used to support the new innovative combination of COG treatment technologies.

This project is divided into method experimental measurements, theoretical development, and geochemical applications. We have completed experimental volumetric measurements on aqueous solutions of CO{sub 2} H{sub 2}S, CH{sub 4}, NH{sub 3} and B(OH){sub 3} at 25 to 432{degree}C and 280 and 350 bar. A vibrating tube densitometer that allows density measurements near bubble point and also measures the bubble pressure was developed and used to measure densities and bubble pressures of aqueous Co{sub 2}. Heat capacity measurements should be completed by the end of the grant period. Simulations of models for methane in water at temperatures to 1000{degrees}C are in progress. In order to facilitate these free energy calculations the possible errors associated with the calculations have been explored in two papers (Wood, 1991; Wood et al., 1991) and methods of controlling and estimating these errors have been developed. Applications of the new data to geochemical processes is now possible. Efforts have focussed on extracting equilibrium constants for carbonic acid dissociation at supercritical condition from published experiments on mineral equilibria in H{sub 2}0-CO{sub 2} fluids (Boehlke and Shock, 1990; and in prep.). As a result, estimates of pKa for carbonic acid are now available at temperatures from 300 to 750{degrees}C …

We have irradiated samples of radiochromic film to doses between 0.005 and lMrad in a Co[sup 60] facility at ANL. The doses computed using the manufacturer's calibration curves for the absorption at 600 and 510 nm have been compared with the dose obtained from ion chamber measurements. Excellent agreement is obtained and high precision can be maintained by baseline measurement of the films prior to irradiation, appropriate choice of film and wavelength used.

Objective is to understand dynamics of elementary ionic collisions at the level of the underlying potential surface by measuring energy and angular distributions of reactively scattered products with crossed beam methods over the relative center-of-mass energy range from 0.3 to several eV. During the past few years, emphasis was on reaction dynamics of anionic species important in combustion, with special emphasis on O{sup {minus}} in proton and hydrogen atom transfer reactions with NH{sub 3}, H{sub 2}O, HF, and CH{sub 4}.

The DWPF is currently carrying out a Startup Test Program which will lead to radioactive operations in the facility. The objective of a significant portion of this program is to demonstrate that the DWPF can reliably make glass which satisfies DOE's product specifications. This objective will be achieved through a series of integrated process campaigns using feeds of various compositions (the Qualification Runs).2 During these campaigns, the DWPF Glass Product Control Programs (GPCP) will be used to ensure that glass is made which meets specifications. The GPCP uses a correlation between glass composition and leach test results to determine whether a particular batch of feed will make acceptable glass (i.e., glass which will meet the specifications).

This investigation is concerned with the separation of gas mixtures using a novel concept of rapid pressure swing absorption (RAPSAB) of gas in a stationary absorbent liquid through gas-liquid interfaces immobilized in the pore mouths of hydrophobic microporous membranes. The process is implemented in a module well-packed with hydrophobic microporous hollow fiber membranes. Before we proceed to RAPSAB studies with reactive absorbents, it is necessary to make an effort to compare experimental results with those predicted by the models. The only model developed so far involved a type of RAPSAB cycle (Mode 3) for which limited data were acquired earlier. A number of experiments have, therefore, been conducted in this mode to characterize the absorption part of the cycle. A new and more compact module (Module No. 5) was made using 840 fibers and a teflon casing inside the stainless steel shell to exactly define the fiber packing density. This allows an exact calculation of Happel's free surface radius. Experiments were carried out using a CO[sub 2]-N[sub 2] mixture of around 10% CO[sub 2] and balanced N[sub 2] using both modules 4 and 5 over a wide range of absorption times.

This quarterly report discusses the technical progress of an Innovative Clean Coal Technology (ICCT) demonstration of advanced wall-fired combustion techniques for the reduction of nitrogen oxide (No[sub x]) emissions from coal-fired boilers. The project is being conducted at Georgia Power Company's Plant Hammond Unit 4 located near Rome, Georgia. The primary goal of this project is the characterization of the low NO[sub x] combustion equipment through the collection and analysis of long-term emissions data. A target of achieving fifty percent NO[sub x] reduction using combustion modifications has been established for the project. The project provides a stepwise retrofit of an advanced overfire air (AOFA) system followed by low NO[sub x] burners (LNB). During each test phase of the project, diagnostic, performance, long-term, and verification testing will be performed. These tests are used to quantify the NO[sub x] reductions of each technology and evaluate the effects of those reductions on other combustion parameters such as particulate characteristics and boiler efficiency.

The ability to measure critical currents in high {Tc} superconducting tapes on a local scale is valuable for optimizing the fabrication process. This paper describes the use of induced currents from a small noncontacting electromagnetic probe to determine the critical current density in a (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x}/Ag tape on a local scale. The technique forces full field penetration into the tape locally and infers the critical current density from the Bean critical state model, accounting for the Ag overlayers. Critical current images of the till can be obtained by scanning the probe over the tape surface with spatial resolution on the order of 1.0 mm. Results for tapes with different microstructures we discussed.

In certain cases droplet direct contact heat transfer rates can be significantly enhanced by the application of an alternating electric field. This field can produce shape oscillations in a droplet which will enhance mixing. The theoretical evaluation of the effect of the interaction of the field with drop charge on the hydrodynamics has been completed for small amplitude oscillations. Previous work with a zero order perturbation method was followed up with a first order perturbation method to evaluate the effect of drop distortion on drop charge and field distribution. The first order perturbation results show secondary drop oscillations of four modes and two frequencies in each mode. The most significant secondary oscillation has the same mode and frequency as the second mode oscillation predicted from the first order perturbation work. The resonant frequency of all oscillations decrease with increasing electric field strength and drop charge. Work is currently underway to evaluate the heat transfer enhancement from an applied alternating electric field.

THE REAL STUFF is an Expanded Media Physics Course aimed at students still in the formative early years of secondary school. Its consists of a working script for an interactive multimedia study unit in basic concepts of physics. The unit begins with a prologue on the Big Bang that sets the stage, and concludes with a lesson on Newton's first law of motion. The format is interactive, placing the individual student in control of a layered hypermedia'' structure that enables him or her to find a level of detail and difficulty that is comfortable and meaningful. The intent is to make physics relevant, intellectually accessible and fun. On-screen presenters and demonstrators will be females and males of various ages, ethnicities and backgrounds, and will include celebrities and physicists of note. A lean, layered design encourages repeated, cumulative study and makes the material useful for self-directed Teaming even by college students. THE REAL STUFF introduces a new science teaching paradigm, a way to teach science that will engage even students who have declined'' to be interested in science in the past. Increased participation in science by women, African-Americans and Spanish-speaking students is a particular goal.

The results from the tests of the first large area (4 [times] 4 cm[sup 2]) planar silicon drift detector prototype in a pion beam are reported. The measured position resolution in the drift direction is ([sigma]=40 [plus minus] 10)[mu]m.