Efficiency evaluation and consumer economic analysis of domestic water heaters

The performances of one gas-fired and two electric storage-type water heaters were characterized experimentally as a function of water tank temperature. For both types of heaters the application of additional insulation was highly cost effective. For the gas-fired water heater the pilot burner flue losses (92% at a water temperature of 150/sup 0/F (65.6/sup 0/C)) were reduced in a cost-effective manner by either pilot-orifice restriction or flue blocking with electric ignition. In addition, an electrically powered burner, with flue modifications, increased the heat-exchange efficiency of the main burner from 72 to 85% at 160/sup 0/F (71.1/sup 0/C). The heat-loss rate per unit of bare-tank area is a useful number in assessing the energy-conservation potential of a water heater

Test of Axel-Brink predictions in the /sup 167/Er(n,. gamma. )/sup 168/Er reaction

The average radiation widths of primary ..gamma.. rays in the reaction /sup 167/Er(n,..gamma..)/sup 168/Er are in reasonable agreement with the Axel-Brink predictions based on a giant dipole resonance model

Resonance parameters, capture. gamma. -rays and reaction mechanism in /sup 98/ /sup 100/Mo + n

In recent years the mechanism of the neutron capture reaction has found wide interest due to the detection of ''non-statistical'' effects. Among the most distinct examples for non-statistical effects in resonance neutron capture are the strong p-wave resonances in the Mo isotopes /sup 92/Mo and /sup 98/Mo. Especially in the case of /sup 98/Mo, it has been shown that the large partial radiative widths can be quantitatively explained on the basis of a simple version of the valence model. Like /sup 98/Mo, also the neighboring isotope /sup 100/Mo shows strong p-wave resonances at low neutron energies. Therefore, /sup 100/Mo provides another interesting test case for the validity of the valence model. Thus neutron resonances in /sup 100/Mo were studied at the Oak Ridge electron linear accelerator time-of-flight facility. The transmission of two oxide samples (97.4% /sup 100/Mo) was measured at an 80 m flight path and the neutron capture cross section was measured at 40 m. Resonance analysis yielded parameters of 123 resonances. Capture ..gamma..-ray spectra from 11 resolved resonances have been measured with a Ge(Li)-detector at a 10 m flight path. Contrary to the neighboring nuclei, partial radiative widths of strong p-wave resonances are not in agreement with valence model predictions

Measurement of soluble solids content in watermelon by Vis/NIR diffuse transmittance technique

Watermelon is a popular fruit in the world with soluble solids content (SSC) being one of the major characteristics used for assessing its quality. This study was aimed at obtaining a method for nondestructive SSC detection of watermelons by means of visible/near infrared (Vis/NIR) diffuse transmittance technique. Vis/NIR transmittance spectra of intact watermelons were acquired using a low-cost commercially available spectrometer operating over the range 350~1000 nm. Spectra data were analyzed by two multivariate calibration techniques: partial least squares (PLS) and principal component regression (PCR) methods. Two experiments were designed for two varieties of watermelons [Qilin (QL), Zaochunhongyu (ZC)], which have different skin thickness range and shape dimensions. The influences of different data preprocessing and spectra treatments were also investigated. Performance of different models was assessed in terms of root mean square errors of calibration (RMSEC), root mean square errors of prediction (RMSEP) and correlation coefficient (r) between the predicted and measured parameter values. Results showed that spectra data preprocessing influenced the performance of the calibration models. The first derivative spectra showed the best results with high correlation coefficient of determination [r=0.918 (QL); r=0.954 (ZC)], low RMSEP [0.65 °Brix (QL); 0.58 °Brix (ZC)], low RMSEC [0.48 °Brix (QL); 0.34 °Brix (ZC)] and small difference between the RMSEP and the RMSEC by PLS method. The nondestructive Vis/NIR measurements provided good estimates of SSC index of watermelon, and the predicted values were highly correlated with destructively measured values for SSC. The models based on smoothing spectra (Savitzky-Golay filter smoothing method) did not enhance the performance of calibration models obviously. The results indicated the feasibility of Vis/NIR diffuse transmittance spectral analysis for predicting watermelon SSC in a nondestructive way