Francis T. Wang

Electrochemical Treatment of Mixed and Hazardous Wastes: Oxidation of Ethylene Glycol and Benzene by Silver (II)

In the future, mediated electrochemical oxidation (MEO) may be used for the ambient temperature destruction of hazardous waste and for the conversion of mixed waste to low-level radioactive waste. We have studied the MEO of ethylene glycol and benzene, two model compounds, in an electrochemical reactor. The reactor had a rotating-cylinder anode that was operated well below the limiting current for Ag(II) generation. Rates of CO 2 generation were measured and used to calculate both destruction and current efficiencies for the process. Gas chromatography with mass spectrometry (GC/MS) was used to identify several reaction intermediates

Single fibre optic fluorescence pH probe

Fibre optic sensing is a growing technology in analytical chemistry. Scattering, absorbance, reflectance and luminescence spectroscopic measurements have been made using fibre waveguides. Fluorescence is particularly suited for use in fibre sensing because of its sensitivity and versatility, and the ease with which this type of measurement may be implemented with a single fibre optic.The probe configuration used in this study for pH measurement consists of fluorescein isothiocyanate (FITC) covalently bonded to a porous glass bead. This bead is attached to a single, multi-mode optical fibre, which conducts both the excitation and emission radiations. The increase in fluorescence intensity, as the acid form of the immobilised FITC is converted to its basic form, is related to the pH. The dynamic range of this miniature probe is pH 3–7 and this can be extended by decreasing the dye loading. The response time is between 20 and 35 s, depending on the capacity.

Destruction of Chlorinated Organics by Cobalt(III)‐Mediated Electrochemical Oxidation

In the future, mediated electrochemical oxidation (MEO) may be used for the ambient temperature destruction of hazardous waste and for the conversion of mixed waste to low-level radioactive waste. In this paper, the authors study the Co(III) mediated electrochemical oxidation of ethylene glycol, 1,3-dichloro-2-propanol, 2-monochloro- 1-propanol, and isopropanol in sulfuric acid. The electrochemical reactor had a rotating cylinder anode that was operated well below the limiting current for Co(III) generation. Rates of CO[sub 2] generation were measured and used to calculate both destruction and current efficiencies for the process. The authors find that electrode separators can be eliminated in MEO processes based upon Co(III) and sulfuric acid. Electrodes must be separated by ion exchange membranes in classical Ag(II)-based processes.

Clinical measurements using fiber optics and optrodes

Fiber optics, optrodes, and fluorescence spectroscopy have been combined to form the new technology of remote fiber fluorimetry (RFF). Both in-vivo and in-vitro clinical measurements can be made by using this technique. The optrode, a fiber termination with preselected chemical or physical properties, is attached to the distal end of the optical fiber so that specific, in-situ measurements can be made. RFF systems for pH, blood pressure, oxygen, and carbon dioxide are being completed, and other optrodes are in the development stages.

Development of integrated mechanistically-based degradation-mode models for performance assessment of high-level waste containers

A key component of the Engineered Barrier System (EBS) being designed for containment of spent-fuel and high-level waste at the proposed geological repository at Yucca Mountain, Nevada is a two-layer canister. In this particular design, the inner barrier is made of a corrosion resistant material (CRM) such as Alloy 825, 625 or C-22, while the outer barrier is made of a corrosion-allowance material (CAM) such as A516 Gr 55, a carbon steel, or Monel 400. At the present time, Alloy C-22 and A516 G4 55 are favored.

Organic Nonlinear Crystals And High Power Frequency Conversion

We are searching for new second and third harmonic generators among the salts of organic acids and bases. We discuss the relevant properties of crystals from this group of compounds, including their nonlinear and phasematching characteristics, linear absorption, damage threshold and crystal growth. In addition, we summarize what is known concerning other nonlinear optical properties of these crystals, such as two-photon absorption, nonlinear refractive index, and stimulated Raman thresholds. A preliminary assessment is made of the potential of these materials for use in future high power, large aperture lasers such as those used for inertial confinement fusion experiments.