title: Evaluation of apparent viscosity of Para rubber latex by diffuse reflection near-infrared spectroscopy.
abstract: Near-infrared spectroscopy in diffuse reflection mode was used to evaluate the apparent viscosity of Para rubber field latex and concentrated latex over the wavelength range of 1100 to 2500 nm, using partial least square regression (PLSR). The model with ten principal components (PCs)  developed using the raw spectra accurately predicted the apparent viscosity with correlation coefficient (r), standard error of prediction (SEP), and bias of 0.974, 8.6 cP, and -0.4 cP, respectively. The ratio of the SEP to the standard deviation (RPD) and the ratio of the SEP  to the range (RER) for the prediction were 4.4 and 16.7, respectively. Therefore, the model can be used for measurement of the apparent viscosity of field latex and concentrated latex in quality assurance and process control in the factory.
authors.affiliation: Curriculum of Agricultural Engineering, Department of Mechanical Engineering, Faculty of Engineering, King Mongkut's Institute of Technology Ladkrabang, Bangkok 10520, Thailand. kspanman@kmitl.ac.th
authors.forename: Panmanas
authors.initials: P
authors.lastname: Sirisomboon
authors.forename: Rawiphan
authors.initials: R
authors.lastname: Chowbankrang
authors.forename: Phil
authors.initials: P
authors.lastname: Williams
mesh_terms: D028482:Hevea / Q000737:chemistry; D016018:Least-Squares Analysis; D025341:Principal Component Analysis; D012408:Rubber / Q000737:chemistry*; D019265:Spectroscopy, Near-Infrared / Q000379:methods*; D014783:Viscosity
chemical_list: D012408:Rubber