Predicting tenderness in today's beef supply could be advantageous to packers and consumers. In this study (n = 1,137 carcasses), visible-near-infrared, electrical impedance, pH and Minolta CIE L*, a*, and b* color space values were examined as predictors of beef 1, 7, and 14 d Warner-Bratzler (N) or Slice Shear (N) force values as estimators of beef tenderness. Visible-NIR at 350 to 1830 nm, electrical impedance, and color space values were taken at the beef packing plant, along with carcass data. Strip loins were transported to Texas A & M University where pH was taken. Six steaks were taken from the anterior end of the strip loin and randomly assigned to either Warner-Bratzler shear force (WBSF) after 1, 7, or 14 days, or Slice shear force (SSF) after 1, 7, and 14 days of post-harvest aging at 2 degrees C. Shears were taken on assigned days. Shear force values were highly correlated with each other (r = 0.37 to 0.56 for WBSF and r = 0.75 to 0.78 for SSF) (P < 0.05). Within the independent variables, reflectance values for mid-range wavelengths (562nm-1193nm) were found to be most highly correlated with the dependent variables (P < 0.05). pH and color spaces values were more highly correlated (P < 0.05) to slice shears values then to Warner-Bratzler shears force values. Electrical impedance was the least significant with r values of 0.00 to 0.14. When Visble-NIR reflectance values were used in stepwise regression equations to predict 1, 7, or 14 d WBSF or 1, 7, or 14 d SSF, prediction equations for 14 d WBSF and SSF had the highest R^2 (0.14 and 0.36, respectively). Stepwise regression equations that included pH and color space values had the highest R^2 for 7 d WBSF and 1 d SSF (0.22 and 0.28, respectively). Electrical impedance alone in a stepwise regression equation had the highest R^2 for 1 and 14 d WBSF and 1 and 7 d SSF (0.02 and 0.03, respectively). Stepwise regression equations that included pH, color space values, and electrical impedance had the highest R^2 for 7 d WBSF and 14 d SSF (0.25 and 0.24, respectively). When pH, color space values, electrical impedance, and Visible-NIR were used, 7 d WBSF and 1 d SSF had the highest R^2 (0.38 and 0.34, respectively). Stepwise regression equations that included pH, color space values, and Visible-NIR had the highest R^2 for 7 d WBSF and 14 d SSF (0.30 and 0.44, respectively). For predicting 14 d Warner-Bratzler shear force, a R^2 of 0.20 was found using Visible-NIR, pH and color space values. When used, the partial least squares equation predicted tenderness with an 85 percent success rate. For predicting 14 d Slice shear forces, a R^2 of 0.40 was found. When used, the partial least squares equation had a 100 percent success rate of predicting those steaks found tender to be tender for Slice shear force. There was an 85 percent success rate for predicting 14 d Warner-Bratzler shear forces. Both equations still had little to no success in predicting tough steaks. The Visible-NIR can successfully predict tenderness

Les traitements antireflets (AR) sont très largement utilisés pour améliorer la transmission de systèmes optiques composés de hublots, lentilles, de lames séparatrices,… Dans cette thèse les gammes spectrales visées sont le visible étendu [400-1800nm] et le moyen infrarouge [3,7-4,8µm]. La méthode de nanostructuration par dépôts de films minces utilisant des techniques PVD en incidence oblique (Oblique Angle Deposition) a été choisie car elle permet d’envisager des AR hautes performances sur une large gamme de longueur d’onde, via un procédé industrialisable. L’introduction de porosité via le contrôle des angles de dépôt est utilisée pour nanostructurer l’architecture de chaque couche et de l’empilement ; méthode permettant de modifier et d’optimiser les propriétés optiques des couches constituantes en vue d’un design complet optimal. Une cartographie des indices effectifs accessibles par OAD a été dégagée concernant les trois matériaux déposés (TiO2, SiO2 et Ge). Mais les propriétés optiques de ces couches nanostructurées diffèrent largement de celles des couches denses du fait de la présence d’anisotropie, de gradient d’indice, de diffusion et d’absorption. A partir de caractérisations microstructurales, chimiques et optiques poussées (AFM, MEB, MET, tomographie FIB, tomographie MET, EDX, EELS, spectrophotométrie et ellipsométrie généralisée) un modèle optique analytique plus complexe et couplé à des analyses par éléments finis (FDTD) est présenté. L’ensemble du travail a permis d’élaborer par OAD de simples antireflet bicouches démontrant déjà de hauts niveaux de transmission, supérieurs aux traitements AR existants (interférentiel) ou en développement (Moth-eyes). / Anti-reflective (AR) coatings are widely used to improve the transmission of optical systems composed of window, lenses, separating filters,... In this thesis, the spectral ranges targeted are the extended visible [400-1800nm] and the mid infrared [3.7-4.8µm]. Thin film deposition nanostructuring method using oblique angle deposition (oblique angle deposition) PVD technique was chosen because it allows high performance AR to be considered over a wide wavelength range, by an industrial process. The introduction of porosity with the control of deposition angle is used to nanostructure the architecture of each layer and stack; a method for modifying and optimizing the optical properties of the constituent layers for optimal complete design. A mapping of the effective indices accessible by OAD has been identified for the three materials deposited (TiO2, SiO2 and Ge). However optical properties of these nanostructured layers differ greatly from those of dense layers due to the presence of anisotropy, index gradient, diffusion and absorption. Based on advanced microstructural, chemical and optical characterizations (AFM, SEM, TEM, FIB tomography, TEM tomography, EDX, EELS, spectrophotometry and generalized ellipsometry) a more complex analytical optical model coupled with finite element analyses (FDTD) is presented. All the work has enabled OAD to develop simple two-layer anti-reflective coatings that already demonstrate high levels of transmission, superior to existing (interferential) or work in progress (Moth-eyes) AR treatments.