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.     

Fortieth Anniversary of the New Brunswick Laboratory

Research sponsored by the Office of Energy Research, U.S. Department of Energy, under Contract DE-AC05-84OR21400 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.     

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.     

BOOK REVIEWS

Book reviewed in this article:
Photoconversion Processes for Energy and Chemicals– Energy from Biomass . Edited by D. O. Hall and G. Grassi
Photochemistry on Solid Surfaces . Edited by M. Anpo and T. Matsuura     

Fragmentation of N2 in 410 nm Intense Femtosecond Laser Field

Fragmentations of N2 in linearly polarized femtosecond 410 and 820 nm intense laser fields were studied by using the velocity mapping technique. Different behaviors of N2 at 410 and 820 nm were observed. Both the kinetic energy distributions and angular distributions of fragment ions in 410 nm field show weak dependency on laser intensities in the non- saturation regime, in contrast to the case in 820 nm. Different excited electronic states, i.e., non-Coulombic potentials populated via vertical＇excitation, are suggested to play crucial roles in fragmentations at short wavelength.     

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.     

An efficient implementation of the direct-SCF algorithm on parallel computer architectures

Summary The development and implementation of a parallel direct self consistent field (SCF) Hartree-Fock algorithm, with gradients and random phase approximation solutions is presented. Important details of the structure of the parallel version of DISCO and preliminary results for calculations using the Concurrent Supercomputing Consortium Intel Touchstone Delta parallel computer system are reported. The data show that the algorithms are efficiently parallelized and that throughput of a one processor CRAY X-MP is reached with about 16 nodes on the Delta. The data also indicate sequential code which was not a bottleneck on traditional supercomputers, can become time critical on parallel computers.This work was performed under the auspices of the Office of Basic Energy Sciences, Division of Chemical Sciences, U.S. Department of Energy, under contract DE-AC06-76RLO 1830 for Pacific Northwest Laboratory which is operated by Battelle Memorial Institute for the U.S. Department of Energy.     

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.     

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.     

Some radiochemical separations employed at the Institute of Nuclear and Energy Research-Brazilian Nuclear Energy Commission

Several radiochemical separations have been employed at the Radiochemistry Division of the Institute of Nuclear and Energy Research-Brazilian Nuclear Energy Commision, for the analysis of a number of elements in different kinds of matrices. In the present paper some of these separations applied to the analysis of geological samples, geological and biological reference materials and Brazilian foodstuffs are described. The separation procedures utilized are mainly ion exchange, retention in inorganic exchangers like HAP, TDO and HMD and solvent extraction.     

A self-assembled light-harvesting array of seven porphyrins in a wheel and spoke architecture

[reaction: see text]A shape-persistent cyclic array of six zinc porphyrins provides an effective host for a dipyridyl-substituted free base porphyrin, yielding a self-assembled structure for studies of light harvesting. Energy transfer occurs essentially quantitatively from uncoordinated to pyridyl-coordinated zinc porphyrins in the cyclic array. Energy transfer from the coordinated zinc porphyrin to the guest free base porphyrin is less efficient (phitrans approximately 40%) and is attributed to a F?rster through-space process.     

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.     

Electron energy loss spectroscopy and its application in material science

The physical processes underlying the inelastic scattering of electrons on passing through a solid as well as on travelling outside a solid in the vicinity of a surface are briefly reviewed. Image energy filtering in a Transmission Electron Microscope (EFTEM) for elemental mapping and High Resolution Electron Energy Loss Spectroscopy (HREELS) for the characterization of semiconductor surfaces and layered structures are discussed as representative applications of Electron Energy Loss Spectroscopy (EELS) in material science, with main emphasis on semiconductors.     

Effect of an External Heavy Atom on the Product Yield of Photoinduced Heterocyclization of 2-Azidobenzoic Acid

High Energy Chemistry -     

Concentration of elements in suspended matter discharges to Lerma River,Mexico

The S, K, Ca, Ti, V, Cr, Mn, Fe, Cu, Zn and Pb concentration and the elemental composition of particles in suspended matter from principal discharges to Lerma River, have been evaluated. The elemental concentration in suspended matter has been obtained by Energy Dispersive X-Ray Fluorescence Spectrometry. The elemental composition of particles has been obtained by means of Energy Dispersive X-Ray Spectrometry (EDS). The results show that K, Ca, Ti, Mn and Fe are mainly from natural origin in the Upper Course of the Lerma River (UCLR), where the principal contributions probably come from dragging of soils and sediments in the rainy season and Cr, Cu, Zn and Pb are mainly from anthropogenic origin where the principal contributions come from urban and industrial untreated discharge. The application of Energy Dispersive X-Ray Spectrometry plus Scanning Electron Microscopy is useful in the characterization of suspended matter in natural, anthropogenic and mixed water discharges.     

Comparative Dehalogenation of 1-Chloro-2-Hydroxyethane and 1-Chloro-2-Methoxyethane by γ-Irradiation

High Energy Chemistry -     

On the Interaction of Semiquinones with Iron(III) Ions

High Energy Chemistry -