The enegry idea drought

Research sponsored by the Office of Energy Research, U.S. Department of Energy, under Contract DE-AC05-840R21400 with Martin Marietta Energy Systems, Inc.     

Non-NAA bomb Detection

Research sponsored by the Office of Energy Research, U.S. Department of Energy, under contract DE-AC05-840R21400 with Martin Marietta Energy Systems, Inc.     

Current status of neutron activation analysis and aplied nuclear chemistry

A review of recent scientometric studies of citations and publication data shows the present state of NAA and applied nuclear chemistry as compared to other analytical techniques.Research sponsored by the Office of Energy Research, U. S. Department of Energy, under Contract DE-AC05-84OR21400 with Martin Marietta Energy Systems, Inc.     

Determination of cell asymmetry in temperature-modulated DSC

The quality of measurement of heat capacity by differential scanning calorimetry (DSC) is based on the symmetry of the twin calorimeters. This symmetry is of particular importance for the temperature-modulated DSC (TMDSC) since positive and negative deviations from symmetry cannot be distinguished in the most popular analysis methods. Three different DSC instruments capable of modulation have been calibrated for asymmetry using standard non-modulated measurements and a simple method is described that avoids potentially large errors when using the reversing heat capacity as the measured quantity. It consists of overcompensating the temperature-dependent asymmetry by increasing the mass of the sample pan.On leave from Toray Industries, Inc., Otsu, Shiga 520, JapanOn leave from Toray Research Center, Inc., Otsu, Shiga 520, JapanThis work was supported by the Division of Materials Research, National Science Foundation, Polymers Program, Grant # DMR 90-00520 and the Division of Materials Sciences, Office of Basic Energy Sciences, U. S. Department of Energy at Oak Ridge National Laboratory, managed by Lockheed Martin Energy Research Corp. for the U. S. Department of Energy, under contract number DE-AC0S-96OR22464. Support for instrumentation came from TA Instruments, Inc. and Mettler-Toledo, Research support was also given by ICI Painls, and Toray Industries, Inc.     

Cell asymmetry correction for temperature modulated differential scanning calorimetry

The quality of measurement of heat capacity by differential scanning calorimetry (DSC) is based on strict symmetry of the twin calorimeter. This symmetry is of particular importance for temperature-modulated DSC (TMDSC) since positive and negative deviations from symmetry cannot be distinguished in the most popular analysis methods. The heat capacities for sapphire-filled and empty aluminum calorimeters (pans) under designed cell imbalance caused by different pan-masses were measured. In addition, the positive and negative signs of asymmetry have been explored by analyzing the phase-shift between temperature and heat flow for sapphire and empty runs. The phase shifts change by more than 180° depending on the sign of the asymmetry. Once the sign of asymmetry is determined, the asymmetry correction for temperature-modulated DSC can be made.On leave from Toray Research Center, Inc., Otsu, Shiga 520, JapanThis work was supported by the Division of Materials Research, National Science Foundation, Polymers Program, Grant # DMR 90-00520 and the Division of Materials Sciences, Office of Basic Energy Sciences, U.S. Department of Energy at Oak Ridge National Laboratory, managed by Lockheed Martin Energy Research Corp. for the U.S. Department of Energy, under contract number DE-AC05-960R22464.     

Performance visualization for parallel programs

Summary We describe here a set of graphical performance visualization tools that have been developed at Argonne National Laboratory for increasing one's understanding of the behavior of parallel programsThis work was supported by the Applied Mathematical Sciences subprogram of the Office of Energy Research, U.S. Department of Energy, under contract W-31-109-Eng-38     

Melting of indium by temperature-modulated differential scanning calorimetry

The melting and crystallization of a sharply melting standard has been explored for the calibration of temperature-modulated differential scanning calorimetry, TMDSC. Modulated temperature and heat flow have been followed during melting and crystallization of indium. It is observed that indium does not supercool as long as crystal nuclei remain in the sample when analyzing quasi-isothermally with a small modulation amplitude. For standard differential scanning calorimetry, DSC, the melting and crystallization temperatures of indium are sufficiently different not to permit its use for calibration on cooling, unless special analysis modes are applied. For TMDSC with an underlying heating rate of 0.2 K min^–1 and a modulation amplitude of 0.5–1.5 K at periods of 30–90 s, the extrapolated onsets of melting and freezing were within 0.1 K of the known melting temperature of indium. Further work is needed to separate the effects originating from loss of steady state between sample and sensor on the one hand and from supercooling on the other.On leave from Toray Research Center, Inc., Otsu, Shiga 520, Japan.This work was supported by the Division of Materials Research, National Science Foundation, Polymers Program, Grant # DMR 90-00520 and the Division of Materials Sciences, Office of Basic Energy Sciences, U.S. Department of Energy at Oak Ridge National Laboratory, managed by Lockheed Martin Energy Research Corp. for the U.S. Department of Energy, under contract number DEACOS-960R22464. Support for instrumentation came from TA Instruments, Inc. and Mettler-Toledo Inc. Research support was also given by ICI Paints.     

Scintillator-fiber flow-cell radioactivity detector for liquid chromatography

Summary A new type of flow-cell radiation detector for use in liquid chromatography which is packed with aligned scintillator fibers is described. A primary advantage of the fiber packed cell is that light generated by the scintillator is absorbed to a much less extent by the fibers than by the powder scintillator used in conventional flow cells. A detection efficiency of 55% has been obtained for carbon-14 using 0.1-mm diameter hand-pulled glass fibers. Computer modeling has shown that even better results can be obtained by using smaller and more uniform diameter fibers which will allow better packing. The fiber cell also demonstrates back pressures which are a factor of 50 less than the conventional cell and much less susceptibility to absorption of compounds because of its lower surface area. Research sponsored by the Office of Energy Research, U.S. Department of Energy, under contract DE-AC05-840R21400 with Martin Marietta Energy Systems, Inc.     

Spectrophotometric studies of transcurium element halides and oxyhalides in the solid state

The present state of a microscale spectrophotometric technique is described. The unique advantages of applying both spectrophotometric and X-ray powder diffraction methods on the sample, in order to identify and characterize newly synthesized compounds, are also discussed. Analytical Chemistry Division, ORNL. Research sponsored by the Division of Physical Research, United States Energy Research and Development Administration under contracts with Union Carbide Corporation and the University of Tennessee (Knoxville).     

Anwendung der neutronenaktivierungsanalyse zur bestimmung von chemischen elementen in heilschlamm aus einem österreichischen moorbad

The content of various elements of mud from Neydharting Austria, that is used for Fango therapy, was determined by neutron-activation analysis. ASTRA-reactor of the Research Centre Seibersdorf and the reactor of the Institute of Nuclear Energy of the Bulgarian Academy of Sciences, Sofia, were used. The concentrations of Ca, Cr, Sc, Fe, Zn, Rb and Co found in our laboratory were in good agreement with the results reported by the Institute of Nuclear Research and Nuclear Energy of the Bulgarian Academy of Sciences, Sofia. All investigated elements in mud with exception of the relatively high uranium values are in good agreement with the values obtained for the distribution of elements in different culture soils.     

Modulated differential scanning calorimetry in the glass transition region

Temperature-modulated calorimetry (TMC) allows the experimental evaluation of the kinetic parameters of the glass transition from quasi-isothermal experiments. In this paper, model calculations based on experimental data are presented for the total and reversing apparent heat capacities on heating and cooling through the glass transition region as a function of heating rate and modulation frequency for the modulated differential scanning calorimeter (MDSC). Amorphous poly(ethylene terephthalate) (PET) is used as the example polymer and a simple first-order kinetics is fitted to the data. The total heat flow carries the hysteresis information (enthalpy relaxation, thermal history) and indications of changes in modulation frequency due to the glass transition. The reversing heat flow permits the assessment of the first and higher harmonics of the apparent heat capacities. The computations are carried out by numerical integrations with up to 5000 steps. Comparisons of the calculations with experiments are possible. As one moves further from equilibrium, i.e. the liquid state, cooperative kinetics must be used to match model and experiment.On leave from Toray Industries, Inc., Otsu, Shiga 520, Japan.This work was supported by the Division of Materials Research, National Science Foundation, Polymers Program, Grant # DMR 90-00520 and the Division of Materials Sciences, Office of Basic Energy Sciences, U. S. Department of Energy at Oak Ridge National Laboratory, managed by Lockheed Martin Energy Research Corp. for the U. S. Department of Energy, under contract number DE-AC05-96OR22464. Support for instrumentation came from TA Instruments, Inc. Research support was also given by ICI Paints, and Toray Industries, Inc.     

Mercury speciation methods for utility flue gas

Accurate measurement of mercury speciation (Hg⁰ and Hg²⁺) in power plant flue gas is necessary to model the fate and transport of mercury in the atmosphere and understand and evaluate the effectiveness of mercury control technologies. Research work jointly sponsored by the Electric Power Research Institute (EPRI) and the U.S. Department of Energy (DOE) is currently under way at the University of North Dakota Energy & Environmental Research Center to determine whether U.S. Environmental Protection Agency (EPA) Method 29 or other methods can speciate mercury. Five different methods have been tested, and it has been found that EPA Method 29 does not speciate mercury properly in coal-generated flue gas. Two methods that show promise are the tris-buffer and the Ontario Hydro methods. Received: 2 December 1996 / Revised: 5 March 1997 / Accepted: 6 March 1997     

Lithium and beryllium trace determination using heavy-ion activation analysis

In using positrons as analytical tools the experimenter has two quite different options. The first and more obvious is to duplicate electron methods with positrons and see what differences (if any) result. The second is to exploit a unique characteristic of positrons, such as the formation and decay of the positronium atom, to study chemical composition and surface characteristics. Because positrons do not exist freely in our world, they must be obtained from radioactive sources or nuclear interactions. Source intensity has consequently been a limiting factor in experiments that attempt to duplicate electron applications. Some methods of producing and moderating positrons that have been developed here (and elsewhere) are described as well as results from studies using the sources. Surface measurements require less intense sources and yield useful data on materials such as xeolites, silica gels, graphite and alumina. Experimental apparatus, data and interpretation will be discussed.Research sponsored by the Office of Energy Research, U. S. Department of Energy, under Contract DE-AC05-840R21400, with Martin Marietta Energy Systems, Inc.     

Multiple melting peak analysis with gel-spun ultra-high molar mass polyethylene

The multiple melting peaks observed on differential scanning calorimetry (DSC) of ultrahigh molar-mass polyethylene fibers (UHMMPE) are analyzed as a function of sample mass. Using modern DSC capable of recognizing single fibers of microgram size, it is shown that the multiple peaks are in part or completely due to sample packing. Loosely packed fibers fill the entire volume of the pan with rather large thermal resistance to heat flow. On melting, the fibers contract and flow to collect ultimately at the bottom of the pan. This process seems to be able to cause an artifact of multistage melting dependent on the properties of the fibers. A method is proposed to greatly reduce, or even eliminate, errors of this type. The crucial elements of the analysis of melting behavior and melting temperature are decreasing the sample size and packing the individual fibers in a proper geometry, or to introduce inert media to enhance heat transport.This work was supported by the Division of Materials Research, National Science Foundation, Polymers Program, Grant # DMR 90-00520 and the Division of Materials Sciences, Office of Basic Energy Sciences, US Department of Energy at Oak Ridge National Laboratory, managed by Lockheed Martin Energy Research Corp. for the US Department of Energy, under contract number DE-ACOS-96OR22464. Support for instrumentation came from TA Instruments, Inc. and Mettler-Toledo, research support was also given by ICI Paints.     

The chemistry of fuel reprocessing: Present practices,future trends

The chemistry of reprocessing, the recovery and purification of plutonium from uranium and fission products produced in the fuel of a nuclear reactor, was surveyed and is described. Reprocessing presented unique chemical problems because of the intense radioactivity, the extreme degree of separation required, and the diversity of elements present. These challenges were met, and improved processes have evolved with time. After 50 years, improvements are still being introduced into the classical solvent extraction processes. In the future, integration of process steps across the entire fuel cycle and increased attention to waste management and environmental considerations are anticipated.Research sponsored by the Office of Facilities, Fuel Cycle, and Test Programs, U.S. Department of Energy under Contract DE-AC05-84OR21400 with the Martin Marietta Energy Systems, Inc.Operated by Martin Marietta Energy Systems, Inc., for the U.S. Department of Energy.     

Stabilization of divalent californium in crystalline strontium tetraborate

The divalent oxidation state of californium (Cf) has been stabilized in crystalline SrB₄O₇. The ability to generate this less-stable oxidation state in an oxide matrix is significant. Factors promoting this stabilization have been determined. Access to this divalent state and those of many other lanthanide and actinide elements via a rather straightforward laboratory procedure now facilitates their study and characterization.Research sponsored by the Division of Chemical Sciences, Office of Basic Energy Sciences, U.S. Department of Energy under grant DE-FG05-88ER13865 to the University of Tennessee, Knoxville and contract DE-AC05-84OR21400 with Martin Marietta Energy Systems, Inc.     

Research and development activities on radioimmunoassay at CIAE

Research and development activities on the field of radioimmunoassay has been reviewed in the past decade at China Institute of Atomic Energy (CIAE), including polyclonal and monoclonal antibodies, recombinant antigens, radioiodination method and tracer purification, separation systems, and nonisotopic label immunoassay.     

A semi-automated remotely operated system for manipulation of radioactive gases

A remote and semi-automated system for hot cell processing of accelerator produced radioactive gases, such as¹²³Xe,⁷⁷Kr, and²¹¹Rn is described. Detailed construction plans and a listing of the mechanical and electronic components are provided.Research carried out at Brookhaven National Laboratory under contract with the U. S. Department of Energy and supported by its Office of Health and Environmental Research.     

Fabrication of 50-mg252Cf neutron sources for the FDA activation analysis facility

The Transuranium Processing Plant (TPP) at the Oak Ridge National Laboratory (ORNL) has been requested by the Food and Drug Administration (FDA) to furnish 200 mg of²⁵²Cf for use in their new activation analysis facility. This paper discusses the procedure to be employed in fabricating the californium into four neutron sources, each containing a nominal 50-mg of²⁵²Cf. The completed neutron sources will be assayed using a precision fast-neutron counter, decontaminated and loaded into a concreete-shielded shipping container weighing 10.7 Mg for shipment to the FDA facility located at Howard University in Washington, D. C.Research sponsored by the Office of Basic Energy Sciences, U. S. Department of Energy, under contract DE-AC05-840R21400 with Martin Marietta Energy Systems, Inc.