987 resultados para near-infrared spectroscopy
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Along the N-S-transect of DSDP-Sites 5446, 397, 141, and 366, oxygen and carbon isotopes, flux rates of calcium carbonate, terrigenous matter, and biogenic opal, clay minerals and the size distribution of terrigenous partictes were determined in order to assess the ties between atmospheric and oceanic surface and deep-water circulation off northwest Africa during the late Neogene. During the last 9 m.y., both the paleoceanography in the eastern Atlantic and west African paleodimates were intimately correlated with the evolution of the polar ice sheets as reflected in the benthos d18O curves of the 4 DSDP-Sites. These records make it possible to distinguish six major time intervals which were charaterized by long-term persistent regimes of climatic stability or climatic change. Short-term, "Milankovitch"-type cycles superimpose the long-term climatic evolution and may reflect the chronostratigraphic control fluctuations of the solar insolation persisting back to pre-Pleistocene times. Relatively stable, warm climates prevailed during the late Tortonian/early Messinean, 9 to 6 m.y., and the early Pliocene, 4.5 to 3.5 m.y. ago. Based on d18O curves, the amplitudes of short-term climatic variation were generally low, and the ice sheets were smaller than during peak Holocene time. Oceanic circulation and resulting paleoproductivity in upwelling zones were insignificant. The strength of dust supplying meridional trade winds was low (3 to 5 m/s), interglacial-style zonal winds near the ITCZ were dominant, as indicated by the high abundance of kaolinite. Phases of fluvial sediment supply were common. Humidity was characteristic of the climate in northwest Africa for the major part of this time. Major episodes of climatic deterioration in the subtropics occurred in the latest Miocene/early Pliocene, between some 5.6 and 5.2 and between 4.9 and 4.6 m.y. ago, in the late Pliocene, between 3.2 and 2.4 m.y. ago, and again in the Quaternary, near 1 m.y. ago. The episodes were correlated with marked increases of the global ice volume, as revealed by drastic increases of d18O values. They suggest sea-level falls of up to 70 m below the present sea level in the latest Miocene and earliest Pliocene and of 145 m in the latest Pliocene and Quaternary. The climatic changes resulted in strongly enhanced meridional trade winds as suggested by coarser terrigenous grain-sizes, increased mass accumulation rates of eolian dust, and changes in clay-mineral composition from dominantly kaolinite to illite and chlorite. The meridional trade winds reached speeds of 8 to 10 m/s with a maximum near 15 m/s. The enhanced winds probably led t o intensified coastal upwelling as shown by the contemporaneous local increase i n the deposition of biogenic silica and the local depletion of 13C at Site 397. The most drastic environmental changes near 2.4 and 1 m.y. ago coincide with hiatuses which may indicate phases of general erosion due to strongly enhanced deep-water circulation in the northeast At1antic along the northwest African continental margin. The occasional occurrence of quartz grains coarser than 250 m may suggest ice-rafted debris in sediments off Morocco. During these time intervals the climate in NW-Africa was dominantly arid. Nevertheless, fluvial runoff (and humidity) continued to be important during intermittent warm phases of the short-term climatic cycles. During the end and the beginning of (inter-) glacial times, fluvial supply of nutrients seems to be the dominant factor, controling phases of enhanced paleoproductivity observed off northwest Africa, whereas during phases of glacial maximum strenger fertility of (increased) coastal upwelling becomes more important. A long-term evolution of paleoenvironments during the last 40 m.y. is depicted in the sediments of Site 366 and is clearly controlled by the plate tectonic route of this Site. During Oligocene times, Site 366 lay in the center of the equatorial upwelling, as shown by the high content of biogenic silica contributing up to 100 % of the carbonate-free sediment fraction >6 m. The influence of equatorial upwelling abruptly terminated near 15 m.y. ago, a change in the record exaggerated by a hiatus of about 2 m.y. Prior to 25 m.y., the terrigenous input at the paleolatitude of Site 366 was restricted t o eolian sediment supply from South Africa by southeasterly trade winds, as shown by dominantly illite and chlorite in the clay fraction and extremely fine-grained terrigenous matter. Near the Oligocene/Miocene boundary, Site 366 drifted across the equator into the belt of the northeasterly trade winds, which is inferred from the increased content of kaolinite and coarser grain sizes of the terrigenous sediment fraction. The clay-mineral and grain-size compositions of Site 366 do not reflect a noteworthy northward shift of the ITCZ during late Miocene and early Pliocene times, i.e. no marked global circulation asymmetry due to the possible absence of a major Northern Hemisphere glaciation (Flohn 1981). This lack of a more northerly position of the ITCZ may result from a bipolar glaciation already existing during late Miocene times, such as also suggested by the evidence of tillites on Iceland and in southern Alaska during those intervals (e.g., Denton & Amstrong 1969, Mudie & Helgason 1983).
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Depuis que la haute nantiopuret est ncessaire dans lindustrie pharmaceutique, les tudes visant dcouvrir les mcanismes pour lhydrognation nantioslective de ctones ou cto-esters sur les surfaces, et rechercher de nouveaux et plus performants catalyseurs asymtriques, sont dune grande importance. La microscopie effet tunnel (STM), la spectroscopie infrarouge de rflexion-absorption, la spectroscopie de dsorption temprature programme et la spectromtrie de photolectrons induits par rayons X sont des mthodes performantes facilitant la comprhension des mcanismes de raction. En plus de nous permettre de comprendre les mcanismes ractionnels, les tudes peuvent fournir des informations sur la dynamique des ractions en catalyse htrogne ainsi que sur le dveloppement de la thorie de la fonctionnelle de la densit (DFT) afin de calculer des interactions faibles dans les processus de surface. Dautres parts, les calculs DFT fournissent une aide essentielle linterprtation des donnes de STM et spectroscopie de surface. Dans cette thse, certains ctones et cto-esters sur la surface de platine sont tudies par les techniques sophistiques mentionnes ci-dessus. Mes tudes dmontrent que la combinaison de lutilisation de la spectroscopie de routine, des nanotechnologies et de nombreux calculs labors, est une mthode efficace pour tudier les ractions la surface car ces techniques explorent les diffrents aspects de la surface ainsi que sentraident mutuellement lors de certaines interprtations.
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Supernova (SN) is an explosion of a star at the end of its lifetime. SNe are classified to two types, namely type I and II through the optical spectra. They have been categorised based on their explosion mechanism, to core collapse supernovae (CCSNe) and thermonuclear supernovae. The CCSNe group which includes types IIP, IIn, IIL, IIb, Ib, and Ic are produced when a massive star with initial mass more than 8 M explodes due to a collapse of its iron core. On the other hand, thermonuclear SNe originate from white dwarfs (WDs) made of carbon and oxygen, in a binary system. Infrared astronomy covers observations of astronomical objects in infrared radiation. The infrared sky is not completely dark and it is variable. Observations of SNe in the infrared give different information than optical observations. Data reduction is required to correct raw data from for example unusable pixels and sky background. In this project, the NOTCam package in the IRAF was used for the data reduction. For measuring magnitudes of SNe, the aperture photometry method with the Gaia program was used. In this Masters thesis, near-infrared (NIR) observations of three supernovae of type IIn (namely LSQ13zm, SN 2009ip and SN2011jb), one type IIb (SN2012ey), in addition to one type Ic (SN2012ej) and type IIP (SN 2013gd) are studied with emphasis on luminosity and colour evolution. All observations were done with the Nordic Optical Telescope (NOT). Here, we used the classification by Mattila & Meikle (2001) [76], where the SNe are differentiated by the infrared light curves into two groups, namely ordinary and slowly declining. The light curves and colour evolution of these supernovae were obtained in J, H and Ks bands. In this study, our data, combined with other observations, provide evidence to categorize LSQ13zm, SN 2012ej and SN 2012ey as being part of the ordinary type. We found interesting NIR behaviour of SN 2011jb, which lead it to be classified as a slowly declining type.
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Numerous applications within the mid- and long-wavelength infrared are driving the search for efficient and cost effective detection technologies in this regime. Theoretical calculations have predicted high performance for InAs/GaSb type-II superlattice structures, which rely on mature growth of III-V semiconductors and offer many levels of freedom in design due to band structure engineering. This work focuses on the fabrication and characterization of type-II superlattice infrared detectors. Standard UV-based photolithography was used combined with chemical wet or dry etching techniques in order to fabricate antinomy-based type-II superlattice infrared detectors. Subsequently, Fourier transform infrared spectroscopy and radiometric techniques were applied for optical characterization in order to obtain a detector's spectrum and response, as well as the overall detectivity in combination with electrical characterization. Temperature dependent electrical characterization was used to extract information about the limiting dark current processes. This work resulted in the first demonstration of an InAs/GaSb type-II superlattice infrared photodetector grown by metalorganic chemical vapor deposition. A peak detectivity of 1.6x10^9 Jones at 78 K was achieved for this device with a 11 micrometer zero cutoff wavelength. Furthermore the interband tunneling detector designed for the mid-wavelength infrared regime was studied. Similar results to those previously published were obtained.
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Eucalyptus pellita demonstrated good growth and wood quality traits in this study, with young plantation grown timber being suitable for both solid and pulp wood products. All traits examined were under moderate levels of genetic control with little genotype by environment interaction when grown on two contrasting sites in Vietnam. Eucalyptus pellita currently has a significant role in reforestation in the tropics. Research to support expanded of use of this species is needed: particularly, research to better understand the genetic control of key traits will facilitate the development of genetically improved planting stock. This study aimed to provide estimates of the heritability of diameter at breast height over bark, wood basic density, Kraft pulp yield, modulus of elasticity and microfibril angle, and the genetic correlations among these traits, and understand the importance of genotype by environment interactions in Vietnam. Data for diameter and wood properties were collected from two 10-year-old, open-pollinated progeny trials of E. pellita in Vietnam that evaluated 104 families from six native range and three orchard sources. Wood properties were estimated from wood samples using near-infrared (NIR) spectroscopy. Data were analysed using mixed linear models to estimate genetic parameters (heritability, proportion of variance between seed sources and genetic correlations). Variation among the nine sources was small compared to additive variance. Narrow-sense heritability and genetic correlation estimates indicated that simultaneous improvements in most traits could be achieved from selection among and within families as the genetic correlations among traits were either favourable or close to zero. Type B genetic correlations approached one for all traits suggesting that genotype by environment interactions were of little importance. These results support a breeding strategy utilizing a single breeding population advanced by selecting the best individuals across all seed sources. Both growth and wood properties have been evaluated. Multi-trait selection for growth and wood property traits will lead to more productive populations of E. pellita both with improved productivity and improved timber and pulp properties.
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The routine analysis for quantization of organic acids and sugars are generally slow methods that involve the use and preparation of several reagents, require trained professional, the availability of special equipment and is expensive. In this context, it has been increasing investment in research whose purpose is the development of substitutive methods to reference, which are faster, cheap and simple, and infrared spectroscopy have been highlighted in this regard. The present study developed multivariate calibration models for the simultaneous and quantitative determination of ascorbic acid, citric, malic and tartaric and sugars sucrose, glucose and fructose, and soluble solids in juices and fruit nectars and classification models for ACP. We used methods of spectroscopy in the near infrared (Near Infrared, NIR) in association with the method regression of partial least squares (PLS). Were used 42 samples between juices and fruit nectars commercially available in local shops. For the construction of the models were performed with reference analysis using high-performance liquid chromatography (HPLC) and refractometry for the analysis of soluble solids. Subsequently, the acquisition of the spectra was done in triplicate, in the spectral range 12500 to 4000 cm-1. The best models were applied to the quantification of analytes in study on natural juices and juice samples produced in the Paran Southwest Region. The juices used in the application of the models also underwent physical and chemical analysis. Validation of chromatographic methodology has shown satisfactory results, since the external calibration curve obtained R-square value (R2) above 0.98 and coefficient of variation (%CV) for intermediate precision and repeatability below 8.83%. Through the Principal Component Analysis (PCA) was possible to separate samples of juices into two major groups, grape and apple and tangerine and orange, while for nectars groups separated guava and grape, and pineapple and apple. Different validation methods, and pre-processes that were used separately and in combination, were obtained with multivariate calibration models with average forecast square error (RMSEP) and cross validation (RMSECV) errors below 1.33 and 1.53 g.100 mL-1, respectively and R2 above 0.771, except for malic acid. The physicochemical analysis enabled the characterization of drinks, including the pH working range (variation of 2.83 to 5.79) and acidity within the parameters Regulation for each flavor. Regression models have demonstrated the possibility of determining both ascorbic acids, citric, malic and tartaric with successfully, besides sucrose, glucose and fructose by means of only a spectrum, suggesting that the models are economically viable for quality control and product standardization in the fruit juice and nectars processing industry.
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Ce projet de recherche mene en collaboration industrielle avec St-Jean Photochimie Inc. / PCAS Canada vise le developpement et la caracterisation de derives dipyrromethene pour des applications dans le domaine du photovoltaique. La quete du recoltage des photons se situant dans le proche-infrarouge a ete au centre des modifications structurales explorees afin daugmenter lefficacite de conversion des cellules solaires de type organique et a pigments photosensibles. Trois familles de composes integrant le motif dipyrromethene ont ete synthetisees et caracterisees du point de vue spectroscopique, electrochimique, structural ainsi que par modelisation moleculaire afin detablir des relations structures-proprietes. La premiere famille comporte six azadipyrromethenes au potentiel de coordination tetradentate sur des centres metalliques. Le developpement dune nouvelle voie synthetique asymetrique combinee a lutilisation dune voie symetrique classique ont permis dobtenir lensemble des combinaisons de substituants possibles sur les aryles proximaux incluant les noyaux 2-hydroxyphenyle, 2-methoxyphenyle et 2- pyridyle. La modulation du maximum dabsorption dans le rouge a pu etre faite entre 598 et 619 nm. De meme, la presence de groupements methoxyle ou hydroxyle augmente labsorption dans le violet (~410 nm) tel que demontre par modelisation. La caracterisation electrochimique a montre que les derives tetradentates etaient en general moins stables aux processus redox que leur contre-parti bidentate. La deuxieme famille comporte dix derives BODIPY fusionnes de facon asymetrique en position [b]. Laryle proximal a ete modifie de facon systematique afin de mieux comprendre limpact des substituents riches en electron et de la fusion de cycles aromatiques. De plus, ces derives ont ete mis en relation avec une vaste serie de composes analogues. Les resultats empiriques ont montre que les proprietes optoelectroniques de la plateforme sont regies par le degre de communication electronique entre laryle proximal, le pyrrole sur lequel il est attache et le noyau indolique adjacent a ce dernier. Les maximums dabsorption dans le rouge sont modulables entre 547 et 628 nm et la fluorescence des composes se situe dans le proche- infrarouge. Lun des compose sest revele souhaitable pour une utilisation en photovoltaique ainsi qua titre de sonde a pH. La troisieme famille comporte cinq complexes neutres de RuII bases sur des polypyridines et portant un ligand azadipyrromethene cyclometale. Les composes ont montre une forte absorption de photons dans la region de 600 a 800 nm (rouge a proche- infrarouge) et qui a pu etre etendue au-dela de 1100 nm dans le cas des derives portant un ligand terpyridine. Lanalyse des proprietes optoelectroniques de facon empirique et theorique a montre un impact significatif de la cyclometalation et ouvert la voie pour leur etude en tant que photosensibilisateurs en OPV et en DSSC. La capacite dun des complexes a photo-injecter un electron dans la bande de conduction du semi-conducteur TiO2 a ete demontre en collaboration avec le groupe du Pr Gerald J. Meyer a University of North Carolina at Chapel Hill, premier pas vers une utilisation dans les cellules solaires a pigments photosensibles. La stabilite des complexes en solution sest toutefois averee problematique et des pistes de solutions sont suggerees basees sur les connaissances acquises dans le cadre de cette these.
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The unique properties of carbon nanotubes have made them the material of choice for many current and future industrial applications. As a consequence of the increasing development of nanotechnology, carbon nanotubes show potential threat to health and environment. Therefore, development of efficient method for detection of carbon nanotubes is required. In this work, we have studied the interaction of indopentamethinedioxaborine dye (DOB-719) and single-walled carbon nanotubes (SWNTs) using absorption and photoluminescence (PL) spectroscopy. In the mixture of the dye and the SWNTs we have revealed new optical features in the spectral range of the intrinsic excitation of the dye due to resonance energy transfer from DOB-719 to SWNTs. Specifically, we have observed an emergence of new PL peaks at the excitation wavelength of 735 nm and a redshift of the intrinsic PL peaks of SWNT emission (up to 40 nm) in the near-infrared range. The possible mechanism of the interaction between DOB-719 and SWNTs has been proposed. Thus, it can be concluded that DOB-719 dye has promising applications for designing efficient and tailorable optical probes for the detection of SWNTs.
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EChO (Exoplanet atmospheres Characterization Observatory), a proposal for exoplanets exploration space mission, is considered the next step for planetary atmospheres characterization. It would be a dedicated observatory to uncover a large selected sample of planets spanning a wide range of masses (from gas giants to super-Earths) and orbital temperatures (from hot to habitable). All targets move around stars of spectral types F, G, K, and M. EChO would provide an unprecedented view of the atmospheres of planets in the solar neighbourhood. The consortium formed by various institutions of different countries proposed as ESA M3 an integrated spectrometer payload for EChO covering the wavelength interval 0.4 to 16 m. This instrument is subdivided into 4 channels: a visible channel, which includes a fine guidance system (FGS) and a VIS spectrometer, a near infrared channel (SWiR), a middle infrared channel (MWiR), and a long wave infrared module (LWiR). In addition, it contains a common set of optics spectrally dividing the wavelength coverage and injecting the combined light of parent stars and their exoplanets into the different channels. The proposed payload meets all of the key performance requirements detailed in the ESA call for proposals as well as all scientific goals. EChO payload is based on different spectrometers covering the spectral range mentioned above. Among them, SWiR spectrometer would work from 2.45 microns to 5.45 microns. In this paper, the optical and mechanical designs of the SWiR channel instrument are reported on.
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By virtue of its proximity and richness, the Virgo galaxy cluster is a perfect testing ground to expand our understanding of structure formation in the Universe. Here, we present a comprehensive dynamical catalogue based on 190 Virgo cluster galaxies (VCGs) in the "Spectroscopy and H-band Imaging of the Virgo cluster" (SHIVir) survey, including kinematics and dynamical masses. Spectroscopy collected over a multi-year campaign on 4-8m telescopes was joined with optical and near-infrared imaging to create a cosmologically-representative overview of parameter distributions and scaling relations describing galaxy evolution in a rich cluster environment. The use of long-slit spectroscopy has allowed the extraction and systematic analysis of resolved kinematic profiles: Halpha rotation curves for late-type galaxies (LTGs), and velocity dispersion profiles for early-type galaxies (ETGs). The latter are shown to span a wide range of profile shapes which correlate with structural, morphological, and photometric parameters. A study of the distributions of surface brightnesses and circular velocities for ETGs and LTGs considered separately show them all to be strongly bimodal, hinting at the existence of dynamically unstable modes where the baryon and dark matter fractions may be comparable within the inner regions of galaxies. Both our Tully-Fisher relation for LTGs and Fundamental Plane analysis for ETGs exhibit the smallest scatter when a velocity metric probing the galaxy at larger radii (where the baryonic fraction becomes sub-dominant) is used: rotational velocity measured in the outer disc at the 23.5 i-mag arcsec^{-2} level, and velocity dispersion measured within an aperture of 2 effective radii, respectively. Dynamical estimates for gas-poor and gas-rich VCGs are merged into a joint analysis of the stellar-to-total mass relation (STMR), stellar TFR, and Mass-Size relation. These relations are all found to contain strong bimodalities or dichotomies between the ETG and LTG samples, alluding to a "mixed scenario'' evolutionary sequence between morphological/dynamical classes that involves both quenching and dry mergers. The unmistakable differentiation between these two galaxy classes appears robust against different classification schemes, and supports the notion that they are driven by different evolutionary histories. Future observations using integral field spectroscopy and including lower-mass galaxies should solidify this hypothesis.
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Spectral albedo was measured along a 6 km transect near the Allan Hills in East Antarctica. The transect traversed the sequence from new snow through old snow, firn, and white ice, to blue ice, showing a systematic progression of decreasing albedo at all wavelengths, as well as decreasing specific surface area (SSA) and increasing density. Broadband albedos under clear-sky range from 0.80 for snow to 0.57 for blue ice, and from 0.87 to 0.65 under cloud. Both air bubbles and cracks scatter sunlight; their contributions to SSA were determined by microcomputed tomography on core samples of the ice. Although albedo is governed primarily by the SSA (and secondarily by the shape) of bubbles or snow grains, albedo also correlates highly with porosity, which, as a proxy variable, would be easier for ice sheet models to predict than bubble sizes. Albedo parameterizations are therefore developed as a function of density for three broad wavelength bands commonly used in general circulation models: visible, near-infrared, and total solar. Relevance to Snowball Earth events derives from the likelihood that sublimation of equatorward-flowing sea glaciers during those events progressively exposed the same sequence of surface materials that we measured at Allan Hills, with our short 6 km transect representing a transect across many degrees of latitude on the Snowball ocean. At the equator of Snowball Earth, climate models predict thick ice, or thin ice, or open water, depending largely on their albedo parameterizations; our measured albedos appear to be within the range that favors ice hundreds of meters thick. Citation:
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Avec la disponibilit de capteurs fiables de teneur en eau exploitant la spectroscopie proche infrarouge (NIR pour near-infrared) et les outils chimiomtriques, il est maintenant possible dappliquer des stratgies de commande en ligne sur plusieurs procds de schage dans lindustrie pharmaceutique. Dans cet ouvrage, le schage de granules pharmaceutiques avec un schoir lit fluidis discontinu (FBD pour fluidized bed dryer) de taille pilote est tudi laide dun capteur dhumidit spectroscopique. Des modifications lectriques sont dabord effectues sur le schoir instrument afin dacheminer les signaux mesurs et manipuls un priphrique dacquisition. La conception dune interface homme-machine permet ensuite de contrler directement le schoir laide dun ordinateur portable. Par la suite, un algorithme de commande prdictive (NMPC pour nonlinear model predictive control), base sur un modle phnomnologique consolid du FBD, est excut en boucle sur ce mme ordinateur. Lobjectif est datteindre une consigne prcise de teneur en eau en fin de schage tout en contraignant la temprature des particules ainsi quen diminuant le temps de lot. De plus, la consommation nergtique du FBD est explicitement incluse dans la fonction objectif du NMPC. En comparant une technique dopration typique en industrie (principalement en boucle ouverte), il est dmontr que le temps de schage et la consommation nergtique peuvent tre efficacement grs sur le procd pilote tout en limitant plusieurs problmes dopration comme le sous-schage, le surschage ou le surchauffage des granules.
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The near infrared (NIR) spectroscopy presents itself as an interesting non-destructive test tool as it enables a fast, simple and reliable way for characterizing large samplings of biological materials in a short period of time. This work aimed to establish multivariate models to estimate the crystallinity indices and tensile and burst strength of cellulosic and nanocellulosic films through NIR spectroscopy. NIR spectra were recorded from the films before tensile and bursting strength, and crystallinity tests. Spectral information were correlated with reference values obtained by laboratory procedures through partial least square regression (PLS-R). The PLS-R model for estimating the crystallinity index presented a coefficient of determination in cross-validation (R2cv) of 0,94 and the ratio of performance to deviation (RPD) was 3,77. The mechanical properties of the films presented a high correlation with the NIR spectra: R2p = 0,85 (RPD = 2,23) for tensile and R2p = 0,93 (RPD = 3,40) for burst strength. The statistics associated to the models presented have shown that the NIR spectroscopy has the potential to estimate the crystallinity index and resistance properties of cellulose and nanocellulose films on in-line monitoring systems.
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Espcies forrageiras adaptadas s condies semiridas so uma alternativa para reduzir os impactos negativos na cadeia produtiva de ruminantes da regio Nordeste brasileira devido sazonalidade na oferta de forragem, alm de reduzir custo com o fornecimento de alimentos concentrados. Dentre as espcies, a vagem de algaroba (Prosopis juliflora SW D.C.) e palma forrageira (Opuntia e Nopalea) ganham destaque por tolerarem o dficit hdrico e produzirem em perodos onde a oferta de forragem est reduzida, alm de apresentam bom valor nutricional e serem bem aceitas pelos animais. Porm, devido variao na sua composio, seu uso na alimentao animal exige o conhecimento profundo da sua composio para a elaborao de dietas balanceadas. No entanto, devido ao custo e tempo para anlise, os produtores no fazem uso da prtica de anlise da composio qumico-bromatolgica dos alimentos. Por isto, a espectroscopia de reflectncia no infravermelho prximo (NIRS) representa uma importante alternativa aos mtodos tradicionais. Objetivou-se com este estudo desenvolver e validar modelos de predio da composio bromatolgica de vagem de algaroba e palma forrageira baseados em espectroscopia NIRS, escaneadas em dois modelos de equipamentos e com diferentes processamentos da amostra. Foram coletadas amostras de vagem de algaroba nos estados do Cear, Bahia, Paraba e Pernambuco, e amostras de palma forrageira nos estados do Cear, Paraba e Pernambuco, frescas (in natura) ou pr-secas e modas. Para obteno dos espectros utilizaram-se dois equipamentos NIR, Perten DA 7250 e FOSS 5000. Inicialmente os alimentos foram escaneados in natura em aparelho do modelo Perten, e, com o auxlio do software The Unscrambler 10.2 foi selecionado um grupo de amostras para o banco de calibrao. As amostras selecionadas foram secas e modas, e escaneadas novamente em equipamentos Perten e FOSS. Os valores dos parmetros de referncia foram obtidos por meio de metodologias tradicionalmente aplicadas em laboratrio de nutrio animal para matria seca (MS), matria mineral (MM), matria orgnica (MO), protena bruta (PB), estrato etreo (EE), fibra solvel em detergente neutro (FDN), fibra solvel em detergente cido (FDA), hemicelulose (HEM) e digestibilidade in vitro da matria seca (DIVMS). O desempenho dos modelos foi avaliado de acordo com os erros mdios de calibrao (RMSEC) e validao (RMSECV), coeficiente de determinao (R2 ) e da relao de desempenho de desvio dos modelos (RPD). A anlise exploratria dos dados, por meio de tratamentos espectrais e anlise de componentes principais (PCA), demonstraram que os bancos de dados eram similares entre si, dando segurana de desenvolver os modelos com todas as amostras selecionadas em um nico modelo para cada alimento, algaroba e palma. Na avaliao dos resultados de referncia, observou-se que a variao dos resultados para cada parmetro corroboraram com os descritos na literatura. No desempenho dos modelos, aqueles desenvolvidos com pr-processamento da amostra (pr-secagem e moagem) se mostraram mais robustos do que aqueles construdos com amostras in natura. O aparelho NIRS Perten apresentou desempenho semelhante ao equipamento FOSS, apesar desse ltimo cobrir uma faixa espectral maior e com intervalos de leituras menores. A tcnica NIR, associada ao mtodo de calibrao multivariada de regresso por meio de quadrados mnimos (PLS), mostrou-se confivel para prever a composio qumico-bromatolgica de vagem de algaroba e da palma forrageira. Abstract: Forage species adapted to semi-arid conditions are an alternative to reduce the negative impacts in the feed supply for ruminants in the Brazilian Northeast region, due to seasonality in forage availability, as well as in the reducing of cost by providing concentrated feedstuffs. Among the species, mesquite pods (Prosopis juliflora SW DC) and spineless cactus (Opuntia and Nopalea) are highlighted for tolerating the drought and producion in periods where the forage is scarce, and have high nutritional value and also are well accepted by the animals. However, its use in animal diets requires a knowledge about its composition to prepare balanced diets. However, farmers usually do not use feed composition analysis, because their high cost and time-consuming. Thus, the Near Infrared Reflectance Spectroscopy in the (NIRS) is an important alternative to traditional methods. The objective of this study to develop and validate predictive models of the chemical composition of mesquite pods and spineless cactus-based NIRS spectroscopy, scanned in two different spectrometers and sample processing. Mesquite pods samples were collected in the states of Cear, Bahia, Paraiba and Pernambuco, and samples of forage cactus in the states of Cear, Paraba and Pernambuco. In order to obtain the spectra, it was used two NIR equipment: Perten DA 7250 and FOSS 5000. sSpectra of samples were initially obtained fresh (as received) using Perten instrument, and with The Unscrambler software 10.2, a group of subsamples was selected to model development, keeping out redundant ones. The selected samples were dried and ground, and scanned again in both Perten and FOSS instruments. The values of the reference analysis were obtained by methods traditionally applied in animal nutrition laboratory to dry matter (DM), mineral matter (MM), organic matter (OM), crude protein (CP), ether extract (EE), soluble neutral detergent fiber (NDF), soluble acid detergent fiber (ADF), hemicellulose ( HEM) and in vitro digestibility of dry matter (DIVDM). The performance of the models was evaluated according to the Root Mean Square Error of Calibration (RMSEC) and cross-validation (RMSECV), coefficient of determination (R2 ) and the deviation of Ratio of performance Deviation of the models (RPD). Exploratory data analysis through spectral treatments and principal component analysis (PCA), showed that the databases were similar to each other, and may be treated asa single model for each feed - mesquite pods and cactus. Evaluating the reference results, it was observed that the variation were similar to those reported in the literature. Comparing the preprocessing of samples, the performance ofthose developed with preprocessing (dried and ground) of the sample were more robust than those built with fresh samples. The NIRS Perten device performance similar to FOSS equipment, although the latter cover a larger spectral range and with lower readings intervals. NIR technology associate do multivariate techniques is reliable to predict the bromatological composition of mesquite pods and cactus.
Resumo:
In the agri-food sector, measurement and monitoring activities contribute to high quality end products. In particular, considering food of plant origin, several product quality attributes can be monitored. Among the non-destructive measurement techniques, a large variety of optical techniques are available, including hyperspectral imaging (HSI) in the visible/near-infrared (Vis/NIR) range, which, due to the capacity to integrate image analysis and spectroscopy, proved particularly useful in agronomy and food science. Many published studies regarding HSI systems were carried out under controlled laboratory conditions. In contrast, few studies describe the application of HSI technology directly in the field, in particular for high-resolution proximal measurements carried out on the ground. Based on this background, the activities of the present PhD project were aimed at exploring and deepening knowledge in the application of optical techniques for the estimation of quality attributes of agri-food plant products. First, research activities on laboratory trials carried out on apricots and kiwis for the estimation of soluble solids content (SSC) and flesh firmness (FF) through HSI were reported; subsequently, FF was estimated on kiwis using a NIR-sensitive device; finally, the procyanidin content of red wine was estimated through a device based on the pulsed spectral sensitive photometry technique. In the second part, trials were carried out directly in the field to assess the degree of ripeness of red wine grapes by estimating SSC through HSI, and finally a method for the automatic selection of regions of interest in hyperspectral images of the vineyard was developed. The activities described above have revealed the potential of the optical techniques for sorting-line application; moreover, the application of the HSI technique directly in the field has proved particularly interesting, suggesting further investigations to solve a variety of problems arising from the many environmental variables that may affect the results of the analyses.
