Yes / A transflectance near infra red (NIR) spectroscopy approach has been used to simultaneously measure drug and plasticiser content of polymer melts with varying opacity during hot melt extrusion. A high temperature reflectance NIR probe was mounted in the extruder die directly opposed to a highly reflective surface. Carbamazepine (CBZ) was used as a model drug, with polyvinyl pyrollidone-vinyl acetate co-polymer (PVP-VA) as a matrix and polyethylene glycol (PEG) as a plasticiser. The opacity of the molten extrudate varied from transparent at low CBZ loading to opaque at high CBZ loading. Particulate amorphous API and voids formed around these particles were found to cause the opacity. The extrusion process was monitored in real time using transflectance NIR; calibration and validation runs were performed using a wide range of drug and plasticiser loadings. Once calibrated, the technique was used to simultaneously track drug and plasticiser content during applied step changes in feedstock material. Rheological and thermal characterisations were used to help understand the morphology of extruded material. The study has shown that it is possible to use a single NIR spectroscopy technique to monitor opaque and transparent melts during HME, and to simultaneously monitor two distinct components within a formulation.

Made available in DSpace on 2014-12-17T15:42:13Z (GMT). No. of bitstreams: 1 AlineSM_DISSERT.pdf: 1997460 bytes, checksum: 0ad037938fab17947fef7a249102b4ec (MD5) Previous issue date: 2013-07-31 / Aiming to consumer s safety the presence of pathogenic contaminants in foods must be monitored because they are responsible for foodborne outbreaks that depending on the level of contamination can ultimately cause the death of those who consume them. In industry is necessary that this identification be fast and profitable. This study shows the utility and application of near-infrared (NIR) transflectance spectroscopy as an alternative method for the identification and classification of Escherichia coli and Salmonella Enteritidis in commercial fruit pulp (pineapple). Principal Component Analysis (PCA), Independent Modeling of Class Analogy (SIMCA) and Discriminant Analysis Partial Least Squares (PLS-DA) were used in the analysis. It was not possible to obtain total separation between samples using PCA and SIMCA. The PLS-DA showed good performance in prediction capacity reaching 87.5% for E. coli and 88.3% for S. Enteritides, respectively. The best models were obtained for the PLS-DA with second derivative spectra treated with a sensitivity and specificity of 0.87 and 0.83, respectively. These results suggest that the NIR spectroscopy and PLS-DA can be used to discriminate and detect bacteria in the fruit pulp / Visando ? seguran?a do consumidor, ? de extrema import?ncia identificar a presen?a de contaminantes patog?nicos nos alimentos, pois os mesmos s?o respons?veis por surtos alimentares que dependendo do n?vel de contamina??o pode chegar a causar a morte de quem os consome. Na industria h? uma necessidade de que essa identifica??o de contaminantes seja r?pida e rent?vel. Este estudo mostra a aplica??o e utilidade de medidas espectrais de transflect?ncia no infravermelho pr?ximo (NIR) como um m?todo alternativo para a identifica??o e classifica??o de Escherichia coli e Salmonella Enteritidis em polpa de fruta comercial (abacaxi). An?lise de Componentes Principais (PCA), Modelagem Independente por Analogia Classe (SIMCA) e An?lise Discriminante por M?nimos Quadrados Parciais (PLS-DA) foram utilizados na an?lise. N?o foi poss?vel obter uma separa??o total entre as amostras usando PCA e SIMCA. O PLS-DA apresentou bom desempenho na capacidade de predi??o alcan?ando 87,5% para E. coli e 88,3% para S. Enteritides, respectivamente. Os melhores modelos obtidos para o PLS-DA com os espectros tratados com segunda derivada apresentaram sensibilidade e especificidade de 0,87 e 0,83, repectivamente. Estes resultados sugerem que a espectroscopia NIR e PLS-DA podem ser usados para discriminar e detectar bact?rias na polpa da fruta

In the past few years, studies regarding new bio-based materials have led to an increased attention in the nanoscale product of cellulose, called nanocellulose. This biodegradable and renewable material has interesting physical, optical and thermal properties. The optical properties could be affected by tuning the nanostructure of the material, which makes it interesting for further investigation. The promising properties of nanocellulose can be useful in many different applications. The aim of this work was therefore to study the optical properties of nanocellulose, and to examine if the material is suitable for spectral design of camouflage or in passive cooling applications. The optical properties of a nanocellulose, specifically cellulose nanofiber (CNF), have been studied. Freestanding CNF films and CNF films deposited on glass substrates were made and characterized by spectroscopy, ellipsometry, BRDF measurements, and optical microscopy. The freestanding samples were examined with different CNF concentrations of 0.52% and 1.0%, and different thicknesses. The samples on glass substrates all had a concentration of 1.0% CNF, but with different amount deposited solution which was either drop or spin coated. The freestanding CNF samples show high transmission in the visual region and relatively high emissivity in the atmospheric windows. This implies that it can be used as an effective material for passive radiative cooling. A thicker sample could also be used to increase the emissivity in the atmospheric windows and improve the ability for passive cooling. The low reflectance, and high emissivity in the atmospheric windows can be promising for use in camouflage applications, according to earlier studies. However, the suitable properties are very dependent on the spectral response of the background. Additional measurements need to be performed and more specified scenarios are necessary to draw any further conclusions.