@article{morimoto_mcclure_crowell_stanfield_2003, title={Near infrared technology for precision environmental measurements: Part 2. Determination of carbon in green grass tissue}, volume={11}, ISSN={["0967-0335"]}, DOI={10.1255/jnirs.372}, abstractNote={ Composting is one of the most desirable techniques for reducing waste volume. To make good compost, the correct proportions of the elements carbon and nitrogen (30: 1 ratio) are important. In this paper, carbon quantification of green grass tissue using near infrared (NIR) technology was studied. Separate studies were conducted for the short-wavelength region (SWR = 700–1100 nm, a range that includes part of the visible spectrum) and long-wavelength region (LWR = 1100–2500 nm). Several spectral pretreatments (such as SNV, derivatives etc.) were implemented to optimise the stepwise multiple linear regression (SMLR) and partial least squares (PLS) calibrations. PLS analysis was conducted for all pretreatments. Results showed that the 2nd derivative of standard normal variate (SNV) pretreatment for the LWR and the SNV pretreatment for the SWR gave the best predictions. To simplify the PLS models, a weight index (WI), was defined as the absolute value of product between the regression vector from PLS analysis and the average spectrum. A simple PLS calibration was developed using selected peak wavelengths of regression vector with a minimum WI. The simple PLS models gave better results than the full PLS calibrations. According to this analysis, the C–H stretching of the first overtone at 1860 nm and the C–H stretching of the third overtone at 874 nm were the key bands for the SWR and LWR, respectively. SMLR analysis was performed on the same spectral data used in the PLS analysis. SMLR calibrations were developed using the key band chosen in PLS analysis. Although the performance of the calibrations were not as good as the PLS calibrations, the SMLR model produced acceptable calibrations for both the SWR and LWR. The simple fact that NIR technology can be used to determine both carbon and nitrogen very quickly makes it an ideal technology for monitoring material going into a composting operation. }, number={4}, journal={JOURNAL OF NEAR INFRARED SPECTROSCOPY}, author={Morimoto, S and McClure, WF and Crowell, B and Stanfield, DL}, year={2003}, pages={257–267} }
 @article{mcclure_moody_stanfield_kinoshita_2002, title={Hand-held NIR spectrometry. Part II: An economical no-moving parts spectrometer for measuring chlorophyll and moisture}, volume={56}, ISSN={["0003-7028"]}, DOI={10.1366/000370202760077432}, abstractNote={ The design and performance of a low-cost no-moving-parts handheld NIR spectrometer are discussed. Dubbed the TWmeter, this device was conceived for use by researchers and others in developing countries unable to afford more costly technology found in developed countries. Two design features contribute to the novelty of this spectrometer: (1) three unfiltered light emitting diodes (LEDs) with peak emissions at 700, 880, and 940 nm for measuring chlorophyll in plant tissue and moisture in paper, and (2) a silicon intensity-to-frequency detector (a silicon detector with an integral voltage-to-frequency converter). The latter feature allows an ordinary microcomputer to obtain intensity measurements by counting for a fixed length of time, thus avoiding the need for higher-priced analog-to-digital hardware. Performance tests, using multiple linear regression for calibration, demonstrate that chlorophyll and moisture can be determined with a root mean squared standard error of prediction of 0.99 mg/cm2 of leaf surface for a range of 1–8 mg/cm2 and 1.04% (wet basis) for a range of 30–65% moisture, respectively. Development of the TWmeter (costing less than $300 US), demonstrates that spectrometry need not be costly. }, number={6}, journal={APPLIED SPECTROSCOPY}, author={McClure, WF and Moody, D and Stanfield, DL and Kinoshita, O}, year={2002}, month={Jun}, pages={720–724} }
 @article{mcclure_crowell_stanfield_mohapatra_morimoto_batten_2002, title={Near infrared technology for precision environmental measurements: part 1. Determination of nitrogen in green- and dry-grass tissue}, volume={10}, ISSN={["0967-0335"]}, DOI={10.1255/jnirs.333}, abstractNote={ The driving force for this work is rooted in data that confirms the contamination of streams and lakes caused from excessive use of nitrogen, pesticides and other soil amendments. Traditional analytical (wet chemistry) methods are too slow and too costly for detecting ecological abuse. A technology that would characterise the nutritional status of growing plants in a timelier manner (preferably in real time as an applicator moves through the field) is needed to control the volume of amendments. This paper explores the potential of near infrared (NIR) spectrometry for measuring nitrogen in plant tissue. In particular, it discusses the development of nitrogen calibrations, and performance of those calibrations, for both green- and dry-grass tissue. Results, based on collaborative studies by several researchers indicate that nitrogen can be measured with an SEP of 0.411% and 0.167% for green- and dry-grass tissue, respectively. }, number={3}, journal={JOURNAL OF NEAR INFRARED SPECTROSCOPY}, author={McClure, WF and Crowell, B and Stanfield, DL and Mohapatra, S and Morimoto, S and Batten, G}, year={2002}, pages={177–185} }
 @article{morimoto_mcclure_stanfield_2001, title={Hand-held NIR spectrometry: Part I: An instrument based upon gap-second derivative theory}, volume={55}, ISSN={["0003-7028"]}, DOI={10.1366/0003702011951489}, abstractNote={ A hand-held near-infrared (NIR) meter (called the Gmeter), based upon gap-second derivative (GSD) theory, was designed, constructed, and performance-tested. The design incorporated narrow-band interference filters for isolating the three wavelengths required by the GSD calculations. A microprocessor was included in the design to facilitate both stand-alone and personal computer (PC) operation. The Gmeter was mounted in a caddy for making measurements within the laboratory. Performance of the Gmeter was compared with the performance of a FOSS NIRSystems Model 6500 spectrophotometer for measuring protein in soy-protein/sugar mixtures and for measuring nitrogen in fescue grass tissue. Two calibrations were developed on both instruments: (1) single-term GSD equations and (2) three-term (log 1/ R) multiple linear regression (MLR) equations. Second-derivative calibration experiments on the Model 6500 spectrophotometer formulated the basis for selecting the three filters in the Gmeter. Model 6500 data indicated that the GSD calibration [coefficient of variation (CV) = 5.14%] performed better than a three-term MLR equation (CV = 8.0%). In addition, the Gmeter performed almost as well (CV = 6.30%) as the Model 6500 (CV = 5.14%) for measuring protein in the mixtures using single-term GSD equations. An exciting extra in this study was the fact that measurements from the same three filters selected for determining protein in protein/sugar mixtures could be used for determining nitrogen (CV = 17.2%) in dry-grass tissue. }, number={2}, journal={APPLIED SPECTROSCOPY}, author={Morimoto, S and McClure, WF and Stanfield, DL}, year={2001}, month={Feb}, pages={182–189} }