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Articles you may be interested inInteraction of wide band gap single crystals with 248 nm excimer laser radiation. V. The role of photoelectronic processes in the formation of a fluorescent plume from MgOThe reaction of hot hydrogen atoms with N 2 0 to form OH and N2 has been studied. The hot hydrogen atoms were generated by the photolysis of HI at 248 nm which produces a bimodal distribution of hydrogen atoms having 43.6 and 22.0 kcallmol of translat!on~l energy. The OH produced was monitored by laser-induced fluorescence in the A-X transition [(0,0) band]. The nascent rotational distribution of this hot reaction was found to be characterized by a Boltzman temperature of 4700 ± 300 K.

It was found earlier that moisture content (MC) of intact kernels of grain and nuts could be determined by Near Infra Red (NIR) reflectance spectrometry. However, if the MC values can be determined while the nuts are in their shells, it would save lot of labor and money spent in shelling and cleaning the nuts. Grain and nuts absorb low levels of NIR, and when NIR radiation is incident on them, a substantial portion of the radiation is reflected back. Thus, studying the NIR reflectance spectra emanating from in-shell peanuts, an attempt is made for the first time to determine the MC of in-shell peanuts. In-shell peanuts of two different market types, Virginia and Valencia, were conditioned to different moisture levels between 6% and 26% (wet basis), and separated into calibration and validation groups. NIR absorption spectral data from 1000 nm to 2500 nm in 1 nm intervals were collected from both groups. Measurements were obtained on 30 replicates within each moisture level. Reference MC values for each moisture level in these groups were obtained using standard air-oven method. Partial Least Square (PLS) analysis was performed on the calibration data, and prediction models were developed. The Standard Error of Calibration (SEC), and R² of the calibration models were computed to select the best calibration model. The selected models were used to predict the moisture content of peanuts in the validation sets. Predicted MC values of the validation samples were compared with their standard air-oven moisture values. Goodness of fit was determined based on the lowest Standard Error of Prediction (SEP) and highest R² value obtained for the prediction models. The model, with reflectance plus normalization spectral data with an SEP of 0.74 for Valencia and 1.57 for Virginia type in-shell peanuts was selected as the best model. The corresponding R² values were 0.98 for both peanut types. This work establishes the possibility of sensing MC of intact in-shell peanuts by NIR reflectance method, and would be useful for the peanut and allied industries

There are some commercial instruments available that use near-infrared (NIR) radiation measurements to determine the moisture content (MC) of a variety of grain products, such as wheat and corn, without the need of any sample grinding or preparation. However, to measure the MC of peanuts with these instruments, the peanut kernels have to be chopped into smaller pieces and filled into the measuring cell. This is cumbersome, time consuming, and destructive. An NIR reflectance method is presented here by which the average MC of about 100 g of whole kernels could be determined rapidly and nondestructively. The MC range of the peanut kernels tested was between 8% and 26%. Initially, NIR reflectance measurements were made at 1 nm intervals in the wavelength range of 1000 to 1800 nm, and the data were modeled using partial least squares regression (PLSR). The predicted values of the samples tested in the above range were compared with the values determined by the standard air-oven method. The predicted values agreed well with the air-oven values, with an R 2 value of 0.93 and a standard error of prediction (SEP) of 1.18. Using the PLSR beta coefficients, five key wavelengths were identified, and MC predictions were made using multiple linear regression (MLR). The R 2 and SEP values of the MLR model were 0.91 and 1.09, respectively. Both methods performed satisfactorily and, being rapid, nondestructive, and noncontact, may be suitable for continuous monitoring of MC of grain and peanuts as they move on conveyor belts during their processing.

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