Historical trends of PCDD/Fs and CO-PCBs in a sediment core collected in Sendai Bay, Japan

The vertical distribution of dioxins in a sediment core was investigated to elucidate historical trends of dioxins discharged into Sendai Bay, Japan. The dioxin concentration was 410 pg/g dry weight (dw) in sediments deposited in the mid-1930s and 3870 pg/g dw in those deposited in the mid-1980s. Dioxin fluxes increased from the mid-1930s and then reached a maximum in the mid-1980s. 1,3,6,8-TeCDD+1,3,7,9-TeCDD, OCDD, and Co-PCB concentrations were 110, 140, and 26 pg/g dw, respectively, in mid-1930s sediments, and reached maximums of 1800, 1100, and 200 pg/g dw, respectively, in mid-1980s sediments. Shipments to Miyagi Prefecture of CNP and PCP products, the major sources of 1,3,6,8-TeCDD+1,3,7,9-TeCDD and OCDD, were highest in 1975 (4700t) and 1970 (3100t), respectively; and in Japan, the amount of PCBs, the major source of Co-PCB congeners, used was highest (11,100t) in 1970. Thus, the period for which the maximum concentrations of 1,3,6,8+1,3,7,9-TeCDD, OCDD, and Co-PCBs were measured in the sediment core (mid-1980s) did not correspond to the time of maximum use of CNP, PCP, or PCB products, but lagged behind by more than 10 years. We attributed this time lag to the time required for the movement of dioxins from Miyagi Prefecture to Sendai Bay.     

Surface expression and release of soluble forms of CD8 and CD23 in CD40- and IL-4-activated mononuclear cells from patients with Graves'' disease (GD)

OBJECTIVE: This study was performed to assess the usefulness of preoperative thin-section CT alone and in combination with physiologic measurements in emphysema patients being evaluated for lung volume reduction surgery. SUBJECTS AND METHODS: Six 1-mm collimation sections through the chest were obtained in 20 patients being evaluated for lung volume reduction surgery. Extent and severity of emphysema were assessed by visually scoring the images. CT scores ranged from 0 to 144. Inspiratory resistance was measured in 12 of 20 patients and was also used to discriminate between responders (change in forced expiratory volume in 1 sec, > or = 150 ml after surgery) and nonresponders (change in forced expiratory volume in 1 sec, < 150 ml after surgery). RESULTS: Four of 20 patients with mild emphysema as revealed by thin-section CT (scores of < 50) did not improve lung function after lung volume reduction surgery. Eight of the remaining 16 patients with moderate to severe emphysema as revealed by thin-section CT (scores of > 50) underwent inspiratory resistance measurement. Those seven patients whose inspiratory resistance measurement exceeded 8.5 cm H2O/l per second did not respond favorably to lung volume reduction surgery (change in forced expiratory volume in 1 sec, < 150 ml). The remaining five patients whose inspiratory resistance measurement was less than 8.5 cm H2O/l per second responded favorably to lung volume reduction surgery. Thus, only five of the 20 patients showed improvement in forced expiratory volume in 1 sec after surgery. CONCLUSION: Our data suggest that among patients with moderate to severe emphysema who are being examined for lung volume reduction surgery, the combination of radiologic and physiologic assessment is more accurate for predicting a favorable response to lung volume reduction surgery than radiologic assessment alone. However, in patients with chronic obstructive pulmonary disease by the American Thoracic Society criteria, mild emphysema as revealed on thin-section CT virtually precludes further workup because these patients are unlikely to respond favorably to lung volume reduction surgery.     

Measurements and correlation of the thermal conductivity of liquid n-paraffin hydrocarbons and their binary and ternary mixtures

The thermal conductivity of four pure normal paraffin hydrocarbons (C₁₁, C₁₄, C₁₅, C₁₆) and binary and ternary mixtures of three n-paraffin hydrocarbons (C₇, C₁₁, C₁₆) have been measured in the temperature range from about 20 to 90°C at atmospheric pressure. Measurements have been performed with the aid of a fully automated transient hot-wire instrument. The accuracy of the reported data is estimated to be ±1.0 to ±1.5%. A new simple and practical equation, which can calculate the thermal conductivity of pure n-paraffin hydrocarbons (4n 16) with the uncertainty of ±1%, has been correlated in terms of temperature and number of carbon atoms based on the present results including some other reliable data. Also, a mixing rule for the mixtures of n-paraffin hydrocarbons was proposed and was adequately confirmed by the present results within the experimental error.     

Corresponding states correlation for the thermal conductivity of molten alkali halides

The principle of corresponding states has been applied to the thermal-conductivity data for molten alkali halides which have been obtained by recent forced Rayleigh scattering measurements. The theory, which was developed by Harada et al. for the transport properties of uni-univalent molten salts, is based on the fluctuation-dissipation theorem with the pair interaction between ions composed of core repulsive and Coulombic potentials. Four characteristic parameters specific to each salt have been used to reduce the thermal conductivity and temperature. It has been found that the thermal conductivity of molten alkali halides is adequately correlated by the corresponding-states correlation ( ^* 1/T ^*) within experimental accuracy. By employing the correlation, the thermal conductivity of molten alkali fluorides, which could not be measured by the forced Rayleigh scattering method, is predicted.Paper dedicated to Professor Joseph Kestin.     

A study on concrete degradation during molten core/concrete interactions

A series of MCCI tests was performed in COTELS project at NUPEC to examine concrete degradation characteristics during MCCI with and without water addition onto the debris. Molten stainless steel or a mixture composed of UO₂, ZrO₂, Zr and stainless steel was slumped into a two-dimensional concrete trap, where volumetric decay heat generation was simulated by an induction heating technique. The results of dry MCCI tests implied that concrete ablation was dominated by melting of aggregates when the debris was crusted and cement was thermally weaker than aggregates. Without presence of stable crust, unmolten aggregates were possible to relocate upward due to the density difference from the debris. Concrete responses under a wet condition showed a tendency that water migrated into thermally degraded concrete. A preliminary water migration model was incorporated into COCO code for transient heat conduction. The prediction by COCO code agreed with the tendency of concrete thermal responses observed in the dry and wet MCCI tests.     

Stable propagation of non-Gaussian beams in a multiple-pass cell

To apply annular output beams emitted from an unstable resonator to a multiple-pass cell (MPC) for Raman conversion, we studied the mode-matching condition of non-Gaussian beams to a MPC using beam propagation analysis based on Laguerre-Gaussian functions. During transits of the MPC, the radial profile of an annular beam changes between annular and Airy patterns. Although such behavior indicates that it is impossible to achieve complete mode matching of an annular beam, we found a quasi-mode-matching condition under which the variation of beam size was minimized. The above theoretical analysis was verified experimentally using a CO(2) laser beam prepared for a para-hydrogen Raman laser.     

Folded-type rectangular loop antenna with tunable circuit

A design for a small and tunable loop antenna is presented. This design enables the higher-order mode resonant frequency to become low while keeping the radiation pattern in good shape. The use of a tunable circuit to utilise higher-order mode for bandwidth enhancement has been investigated. The measured and simulated radiation patterns and voltage standing wave ratio are given.     

Predicting struvite formation for phosphorus recovery from human urine using an equilibrium model.

Interest in phosphorus recovery from urine diverted from faeces has been growing recently. Phosphorus in urine can be precipitated out as struvite (MgNH4PO4 x 6H2O) with addition of magnesium salt under alkaline conditions. Struvite formation, however, should be more well understood for its practical application. We predicted the struvite formation with a development of a new equilibrium model. The model considered the formation of eight different kinds of precipitates, including struvite, with effects of ionic strength and temperature. In addition, experiments on struvite formation in urine were conducted for the model validation. The model prediction of struvite formation had good agreement with the experimental results. The optimum pH to form struvite was predicted to be 9.4-9.7. In order to precipitate 99% of phosphate in urine with 1.5 fold Mg concentration to PO4-P, the pH value was necessary to be more than 8.1 based on the model prediction.     

Thermal Conductivity of Ternary Refrigerant Mixtures of HFC-32/125/134a in the Liquid Phase

The liquid thermal conductivity of two ternary mixtures of HFC-32/125/134a (23.0/25.0/52.0 and 19.0/43.8/37.2 wt%) was measured using a transient hot-wire instrument in the temperature ranges from 193 to 293 K and from 213 to 293 K, respectively, and in the pressure range from 2 to 30 MPa. The thermal conductivity has an estimated uncertainty of ±0.7%. For engineering purposes, the thermal conductivity data were correlated using a polynomial in temperature and pressure for each mixture with a standard deviation of 0.6%.