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.

Solid friction is considered by some to be a fundamental property of two contacting materials, while others consider it to be a property of the larger tribosystem in which the materials are contained. A set of sliding friction experiments were designed to investigate the hypothesis that the unlubricated sliding friction between two materials is indeed a tribosystems-related property and that the relative influence of the materials properties or those of the machine on friction varies from one situation to another. Three tribometers were used: a friction microprobe (FMP), a typical laboratory-scale reciprocating pin-on-flat device, and a heavy-duty commercial wear tester. The slider material was stainless steel (AISI 440C) and the flat specimen material was an ordered alloy of Ni{sub 3}Al (IC-50). Sphere-on-flat geometry was used at ambient conditions and at normal forces ranging from 0.01 N to 100 N and average sliding velocities of 0.01 to 100.0 mm/s. The nominal, steady-state sliding friction coefficient tended to decrease with increases in normal force for each of the three tribometers, and the steady state value of sliding friction tended to increase as the mass of the machine increased. The variation of the friction force during sliding was also a characteristic of the …

The Filter Compartment (FC) in this analysis is a generic reactor airborne activity confinement filter compartment which possesses all the essential physical and mechanical properties of the Savannah River Site (SRS) confinement filters of Reactor Buildings K, L, and P. The filters belong to the Airborne Activity Confinement System (AACS). These filters absorb a significant amount of radioactive effluents from the exhausting air. The seismic excitation is input indirectly from the output of the seismic analysis of the 105 exhaust stack building in the form of floor response spectra. However, the 105 exhaust stack building was analyzed for seismic motions defined by free-field ground response spectra with a ZPA (Zero Period Acceleration) of 0.2G for all three orthogonal components of ground motion and a shape consistent with USNRC Regulatory Guide 1.60. Based upon equivalent dynamic analysis of the FC, DuPont engineers suggested modifications on the existing FC with heavy I-section beams (1). The scope of this phase I'' analysis, as requested by Seismic Engineering (2), is to carry out a scoping analysis'' of Frequency Analysis and Response Spectrum Analysis of the FC with DuPont suggested conceptual modifications. Our suggestion was that the existing FC without conceptual modifications be analyzed first. …

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.

We have made a first study of the calorimetric response to 10 GeV/c charged pions in the transition region between barrel and endcap for the scintillator-tile design pursued at Argonne National Laboratory using the simulation program ANLSIM. For (very nearly) projective tower orientations in the barrel, the crack appears deep within a narrow angular range, causing a loss of the response in that region up to 40%. Pointing the towers onto the beam axis 35 cm or more away from the nominal-interaction point leads to a shortened depth of the barrel-endcap crack as seen by particles incident from the interaction region, cutting the maximum loss down by almost one half. The worsening of the resolution follows the same trend. Introduction of a solenoidal coil in front of the calorimeter causes an overall degradation of the response by an amount nearly comparable to the effect of the crack. Electrons of the same incident momentum are more strongly affected by the coil than pions but see only a much narrower region of degradation by the crack. 15 refs., 6 figs., 2 tabs.

In the project status report for 4/9/90--7/8/90, Table 2 presented update results of a comparative study of coal sample deterioration in several container types including foil laminate bags. This table contained an erroneous entry (foil laminate bag {minus}20 mesh, alkali extraction 65.4% transmittance). The alkali extraction test on {minus}20 mesh coal stored in foil laminate bags for 52 weeks was repeated in duplicate on another bag (after 64 weeks total storage) resulting in a measurement of 96.2% transmittance. This value has been substituted for the erroneous 65.4% value in the corrected copy of Table 2 enclosed with this report. All values of the alkali extraction and Gieseler fluidity tests indicate that the state of preservation of sample in foil laminate bags is excellent. The samples stored by other methods for comparison purposes all showed significant loss in fluid characteristics. One new whole-seam channel sample of the hvAb Pittsburgh seam coal, DECS-12, was collected July 25, 1990 in Greene County, PA. This sample was placed in 30-gallon steel barrels with high-density lid gaskets and purged with argon at the mine. Upon return to Penn State it was promptly processed so that Gieseler fluidity and other routine analyses could be performed.

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 …

The overall objective of the Full-Scale Low-NOx Cell (LNC) Burner Retrofit project is to demonstrate the cost-effective reduction of NOx generated by a large, base-loaded (70% capacity factor or greater), coal-fired utility boiler. Specific objectives include: at least 50% NOx reduction over standard two-nozzle cell burners, without degradation of boiler performance or life; acquire and evaluate emission and boiler performance data before and after the retrofit to determine NOx reduction and impact on overall boiler performance; and demonstrate that the LNC burner retrofits are the most cost-effective alternative to emerging, or commercially- available NOx control technology for units equipped with cell burners. The focus of this demonstration is to determine maximum NOx reduction capabilities without adversely impacting plant performance, operation and maintenance.

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 temperature profiles from a selection of TFTR L-mode discharges are simulated with the 1-1/2-D BALDUR transport code using a combination of theoretically derived transport models, called the Multi-Mode Model. The present version of the Multi-Mode Model consists of effective thermal diffusivities resulting from trapped electron modes and ion temperature gradient ({eta}{sub i}) modes, which dominate in the core of the plasma, together with resistive ballooning modes, which dominate in the periphery. Within the context of this transport model and the TFTR simulations reported here, the scaling of confinement with heating power comes from the temperature dependence of the {eta}{sub i} and trapped electron modes, while the scaling with current comes mostly from resistive ballooning modes. 24 refs., 16 figs., 3 tabs.

This report summarizes the International Conference on Fusion Reactor Materials (ICFRM-4) which was held December 4--9, 1989, in Kyoto, Japan, as well as the results of several workshops, planning meetings, and laboratory visits made by the travelers. The ICFRM-4 is the major forum to present and exchange information on materials research and development in support of the world's fusion development efforts. About 360 papers were presented by the 347 conference attendees. Highlights of the conference are presented. A proposal by the United States to host ICFRM-5 was accepted by the International Advisory Committee. ORNL will be the host laboratory. A meeting of the DOE/JAERI Annex I Steering Committee to review the US/Japan Collaborative Testing of First Wall and Blanket Structural Materials with Mixed Spectrum Fission Reactors was held at JAERI Headquarters on December 1. The Japanese emphasized the critical importance of a resumption of HFIR operation. Even though the HFIR outage has lasted three plus years this program has continued to provide new and important data on materials behavior which has particular relevance to ITER.

Correspondence issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO provided information on equal employment opportunity (EEO) issues in the Internal Revenue Service's (IRS) Midwest District Office."

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO reviewed federal agencies' certification requirements for goods and services, focusing on: (1) the extent and variety of certification activities in the federal government; (2) the extent to which there are policies, procedures, or guidance governing those activities, either governmentwide or within selected agencies; and (3) an agency certification procedure that could serve as an example or best practice for other agencies."

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO provided information on small business tax requirements, focusing on: (1) the federal filing, reporting, and deposit requirements that apply to small businesses; and (2) the actual experience of small businesses in meeting these requirements, including their involvement in the Internal Revenue Service's (IRS) enforcement process."

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO examined the significant differences in two Department of Defense training programs, focusing on the: (1) training categories and military services with the most significant funding changes from the 1998 to the 1999 Future Years Defense Program (FYDP); (2) bases for the changes; and (3) potential impact of the changes on the services' future training budgets."

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO reviewed the Navy's declining ship maintenance workload, focusing on: (1) the Navy's policies and procedures for allocating ship maintenance work to public and private facilities in the Norfolk area; (2) ship maintenance and modernization funding obligated to the Norfolk Naval Shipyard and private ship repair companies during the fiscal years (FY) 1994 through 1998; and (3) the extent to which the Atlantic Fleet's ship maintenance program has been affected by the movement of funds out of the ship depot maintenance program since FY 1994."

Correspondence issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO reviewed the process that the Office of National Drug Control Policy's (ONDCP) Counterdrug Technology Assessment Center (CTAC) uses to fund research and development (R&D) projects."

Correspondence issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO responded to congressional concerns regarding the Department of Veterans Affairs' (VA) efforts to address the year 2000 computer problem, focusing on: (1) VA's ability to achieve year 2000 compliance; (2) VA's work to date on the year 2000 challenge; (3) what areas VA should concentrate on over the next six months to ensure that its highest risks areas are addressed prior to January 1, 2000; (4) identifying any areas where VA has misdirected its efforts; and (5) VA's greatest strengths in the effort to surmount the year 2000 challenge."

Correspondence issued by the General Accounting Office with an abstract that begins "GAO identified weaknesses in the Environmental Protection Agency's (EPA) personnel practices."

Correspondence issued by the General Accounting Office with an abstract that begins "Pursuant to a legislative requirement, GAO provided information on internal control weaknesses identified during GAO's audits of the Federal Deposit Insurance Corporation's (FDIC) 1998 financial statements."

Correspondence issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO reviewed the auctions federal agencies currently use to award rights or sell assets and the way in which they differ."

Correspondence issued by the General Accounting Office with an abstract that begins "GAO identified weaknesses in the Department of Agriculture's (USDA) personnel practices."

A letter report issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO examined: (1) whether exporter notification to the Department of Commerce of proposed sales of high performance computers (HPC) to countries of concern has resulted in license applications and what final action was taken on these licenses; and (2) how Commerce is conducting post-shipment verifications of the use of high performance computers after their export to these countries."