Cada vez mais, a indústria requer métodos em tempo real para o controle de qualidade da carne fresca, a fim de melhorar a eficiência produtiva, garantir homogeneidade dos produtos e atender expectativas do consumidor. No presente trabalho, a imagem hiperespectral foi empregada para avaliação da qualidade da carne de bovinos Nelore com ênfase para a maciez e características relacionadas, e, ainda, a construção de mapas de distribuição das características para observação da variabilidade dessas entre e dentro de amostras. Para investigar se o uso de diferentes grupos musculares aumenta a variabilidade dos valores de referência, promovendo melhora nos modelos de predição e classificação da maciez, foram utilizadas amostras do músculo Longissimus(94) e B. femoris (94) de bovinos Nelore. Para investigar se a seleção da região de interesse (ROI) na imagem no exato local onde foi coletado o cilindro para determinação da força de cisalhamento melhora os modelos de predição e classificação da maciez, foram utilizadas amostras do músculo Longissimus (50). Após a aquisição da imagem (1.000 - 2.500 nm), cada amostra foi avaliada seguindo metodologia tradicional para força de cisalhamento, matéria seca, proteína bruta, lipídios e comprimento de sarcômero. Os dados espectrais e espaciais foram analisados por técnicas quimiométricas e modelos PLSR e PLS-DA foram construídos. Em relação à abordagem com diferentes músculos, os dados foram modelados separadamente para evitar que fenômenos devidos às diferenças musculares fossem equivocadamente atribuídos às características investigadas. Ainda assim, amostras de Longissimus com maciez inaceitável foram classificadas com sensibilidade = 87% e amostras macias de B. femoris com sensibilidade = 90%, ambas na validação externa. Com relação à forma de seleção da ROI, os modelos de classificação utilizando ROI local apresentaram melhor desempenho do que os modelos com ROI de toda a amostra (sensibilidade na validação externa para a classe dura = 33% e 70%, respectivamente). Entretanto, o modelo mais geral tem desempenho melhor na construção de mapas de distribuição da maciez, com de 72% das imagens preditas corretamente classificadas. / Increasingly, industry requires real-time methods for quality control of fresh meat in order to improve production efficiency, ensure product homogeneity and meet consumer expectations. In the present work, the hyperspectral image was used to evaluate the quality of Nellore beef with emphasis on tenderness and characteristics related to it, and also the construction of distribution maps to observe the variability of these characteristics between and within samples. To investigate whether the use of different muscle groups increases the variability of the reference values, improving tenderness prediction and classification models, samples from Longissimus (94) and B. femoris (94) of Nellore cattle were used. To investigate whether the selection of the region of interest (ROI) in the image at the exact location where the shear force cores were collected improves tenderness prediction and classification models, samples from Longissimus muscle were used (50). After image acquisition (1,000 - 2,500 nm), each sample was evaluated following traditional methodology for shear force, dry matter, crude protein, lipids and sarcomere length. The spectral and spatial data were analyzed by chemometric techniques and PLSR and PLS-DA models were constructed. Regarding the approach with different muscles, the data were modeled separately to avoid that phenomena due to muscle differences were mistakenly attributed to the characteristics investigated. Nevertheless, samples from Longissimus with unacceptable tenderness were classified with sensitivity = 87% and tender samples from B. femoris with sensitivity = 90%, both in the external validation. Regarding the ROI selection, the classification models using local ROI presented better performance than the ROI models of the whole sample (external validation sensitivity for the tough class = 33% and 70%, respectively). However, the more general model had better performance in the tenderness distribution maps, with 72% of predicted images correctly classified.

This thesis deals with the continual measurement of the hydrated lime moisture content on the principle of spectral measurements. The theoretical part describes the basic principles of the infrared spectroscopy, Fourier transformation and near infrared spectroscopy, which are used in the process of the spectroscopy measurement of fine particulates moisture content. The practical part of the work describes experiments and the evaluation of moisture hydrated lime measuring results, using gravimetric method and NIR spectroscopy in both the laboratory conditions and the conditions of operation production of hydrated lime as well. The part of the work monitors the spectroscopy measurement moisture values as the dependence on the optical quality of hydrate limes and the process conditions of the measurements.

Organic solar cell (OSC) has been an active research field over the past decades, due to their intrinsic advantages, such as low consumption of materials and energy, the applicability on flexible substrates and the degradability of the organic components. Compared with the solution processing technology using polymers as electron donor materials, small molecule vacuum deposition is regarded as a promising fabrication method, avoiding the use of toxic aromatic solvents and guaranteeing constant batch-to-batch performance. Moreover, it is much easier to realize multi-junction tandem solar cells (TSCs) by thermal deposition, and the leading power conversion efficiency (PCE) of 13.2% was achieved using three different absorbers by vacuum deposition (“Heliatek sets new organic photovoltaic world record efficiency of 13.2%” 2016). In this dissertation, novel electron donor materials are synthesized based on the molecular skeleton of a famous chromophore, boron dipyrromethene (BODIPY), and chemical modifications are carried out to tune the intense absorption bands of these dyes to near infrared (NIR, λ>750,nm) region. Efficient small molecule NIR absorbers are highly required for TSCs, because they can construct a complementary absorption over the visible and NIR spectral region in cooperation with a wide bandgap material. Three β-fused aza-BODIPY molecules with heterocyclic substituents on α-positions are prepared using organolithium reagents and phthalonitrile as the starting materials. The organolithium reagents, namely N-methylpyrrole, N-methylindole and 2-trimethylsilylthiophene, are used instead of commonly used Grignard reagents. Moreover, three corresponding aza-BODIPY derivatives are obtained by replacing one fluorine atom in the BF_{2} moiety by a cyano group. UV-vis absorption spectra reveal that all these materials are strong NIR absorbers, and their abortion in solid state cover a wide range from 600 to 1000,nm. OSCs with these aza-BODIPY donors give a best PCE of 3.0%, which is a reasonable value for the NIR devices with the maximum and the onset of the EQE spectrum around 850 and 950,nm respectively. A series of furan-fused BODIPYs with a electron withdrawing CF_{3} group on the meso-C are synthesized, and the photophysical/electrochemical properties can be tuned easily by the electronic properties of the substituents on the peripheral aromatic rings. The most promising candidate gives a high PCE of 6.1% in a single junction OSC with a J_{sc} of 13.3,mA/cm^{2}, a V_{oc} of 0.73,V, and a FF of 62.7%. A serial connected TSC is fabricated using this BODIPY as the low bandgap donor and a “green” donor, and its EQE spectrum covers a wide range from 400 to 900,nm. The PCE reaches 9.9% with a J_{sc} of 9.9,mA/cm^{2}, a V_{oc} of 1.70,V, and a FF of 59.0%. Based on the general structure of furan-fused BODIPY, alkyl or fluorinated alkyl substituents with larger volume is introduced on either peripheral aromatic rings or the meso-C. The variations that caused by these substituents on the photophysical and electrochemical properties are negligible. The investigations on the OSCs demonstrate that the introduction of these alkyl chain substituents have positive influence on the PCE values, which benefit mainly from the increased photocurrent. However, there is no positive relationship between the device performance and the volume of the alkyl chain substituents. BODIPY molecules have been demonstrated as efficient and promising NIR electron donor materials for vacuum-deposited OSCs. Taking advantages of facile molecular modification, oustanding photophysical behaviors and tunable electrochemical properties, this series of dyes are also intereting for other semiconductor devices.

There is a great need to develop systems that can continuously provide correct information about road surface status depending on the prevailing weather conditions. This will minimize accidents and optimize transportation. In this thesis different methods for the determination of the road surface status have been studied and analyzed, and suggestions of new technology are proposed. Information about the road surface status is obtained traditionally from various sensors mounted directly in the road surface. This information must then be analyzed to create automated warning systems for road users and road maintenance personnel. The purpose of this thesis is to investigate how existing technologies can be used to obtain a more accurate description of the current road conditions. Another purpose is also to investigate how existing technologies can be used to obtain a more accurate description of the current road conditions. Furthermore, the aim is to develop non-contact technologies able to determine and classify road conditions over a larger area, since there is no system available today that can identify differences in road surface status in the wheel tracks and between the wheel tracks. Literature studies have been carried out to find the latest state of the art research and technology, and the research work is mainly based on empirical studies. A large part of the research has involved planning and setting up laboratory experiments to test and verify hypotheses that have emerged from the literature studies. Initially a few traditional road-mounted sensors were analyzed regarding their ability to determine the road conditions and the impact on their measured values when the sensors were exposed to contamination agents such as glycol and oil. Furthermore, non-contact methods for determining the status of the road surface have been studied. Images from cameras working in the visible range, together data from the Swedish Transportation Administration road weather stations, have been used to develop computerized road status classification models that can distinguish between a dry, wet, icy and snowy surface. Field observations have also been performed to get the ground truth for developing these models. In order to improve the ability to accurately distinguish between different surface statuses, measurement systems involving sensors working in the Near-Infrared (NIR) range have been utilized. In this thesis a new imaging method for determining road conditions with NIR camera technology is developed and described. This method was tested in a field study performed during the winter 2013-2014 with successful results. The results show that some traditional sensors could be used even with future user-friendly de-icing chemicals. The findings from using visual camera systems and meteorological parameters to determine the road status showed that they provide previously unknown information about road conditions. It was discovered that certain road conditions such as black ice is not always detectable using this technology. Therefore, research was performed that utilized the NIR region where it proved to be possible to detect and distinguish different road conditions, such as black ice. NIR camera technology was introduced in the research since the aim of the thesis was to find a method that provides information on the status of the road over a larger area. The results show that if several images taken in different spectral bands are analyzed with the support of advanced computer models, it is possible to distinguish between a dry, wet, icy and snowy surface. This resulted in the development of a NIR camera system that can distinguish between different surface statuses. Finally, two of these prototype systems for road condition classification were evaluated. These systems were installed at E14 on both sides of the border between Sweden and Norway. The results of these field tests show that this new road status classification, based on NIR imaging spectral analysis, provides new information about the status of the road surface, compared to what can be obtained from existing measurement systems, particularly for detecting differences in and between the wheel tracks.

Domsjö Fabriker has earlier installed a Near Infrared (NIR) spectrometer after one of their recovery boilers. The purpose is to monitor the reduction efficiency of the boiler and later do process optimization. In this work calibration models for the instrument have been created. 108 green liquor samples have been extracted. A NIR spectrum was recorded for each sample and the samples were subsequently analyzed in laboratory for total alkali, sulfide and total sulfur. Several calibration models were created with multivariate data analysis and their performance and robustness were compared. The best model was able to predict reduction efficiency with a RMSEP of 2.75 percent units. Moreover, models were created for prediction of total alkali with a RMSEP of 0.108 mol/l, sulfides with a RMSEP of 1.95 g/l, total sulfur with a RMSEP of 2.83 g/l and S/Na2 ratio with a RMSEP of 0.022. The result is good enough that the instrument could be used to optimize the process and monitor process disturbances.

Bei Kindern mit Aufmerksamkeitsdefizit-/Hyperaktivitätsstörung (ADHS) konnten Defizite in der Leistung des Arbeitsgedächtnisses nachgewiesen werden. In zahlreichen funktionell bildgebenden Studien zeigte sich außerdem ein mit dem Arbeitsgedächtnis assoziierter Unterschied in der präfrontalen Aktivierung im Vergleich zu Gesunden. Bisher wurde jedoch noch nicht näher analysiert, ob diese Defizite von der Komponente (visuell-räumliches (SWM) oder visuell-bildliches Arbeitsgedächtnis (OWM)) oder dem Prozess des Arbeitsgedächtnisses (untergeordnete Speichersysteme oder zentrale Exekutive) abhängig sind. Diese Arbeit ist die erste, die mit der funktionellen Nah-Infrarot Spektroskopie (fNIRS) das Arbeitsgedächtnis bei Kindern mit ADHS untersucht. Dabei war das Hauptziel zum einen die Replikation von Gruppenunterschieden in Verhalten und präfrontaler Aktivierung und zum anderen die Gewinnung näherer Informationen über die differentielle Ausprägung der präfrontalen Defizite bei ADHS. Die Stichprobe bestand aus 19 Kindern mit ADHS vom kombinierten Typ (DSM-IV) und 19 Kontrollkindern, die vergleichbar waren nach Alter (8-15 Jahre), Geschlecht, Händigkeit und Intelligenz. Das von uns gewählte Paradigma differenzierte zwischen Aufgaben zum OWM und SWM, innerhalb derer wiederum zwei prozessabhängige Phasen (Speicherung und Abgleich) unterschieden wurden, und enthielt zusätzlich eine Kontrollaufgabe (CON). Die präfrontale Aktivierung wurde mittels fNIRS über die Konzentrationsänderungen der Chromophoren oxygeniertes Hämoglobin (O2Hb) und deoxygeniertes Hämoglobin (HHb) bestimmt. Es zeigte sich ein signifikant unterschiedliches Verhalten abhängig von der Bedingung (CON > SWM > OWM). Eine typische präfrontale Aktivierung des Arbeitsgedächtnisses mit der höchsten Aktivierung im dorsolateralen präfrontalen Kortex (DLPFC) beschränkte sich auf die Abgleichphase. Weder in Hinblick auf das Verhalten noch auf die präfrontale Aktivierung konnten signifikante Gruppenunterschiede nachgewiesen werden. Für das Nichtauftreten von Gruppenunterschieden können verschiedene mögliche Gründe angeführt werden. Unter anderem legten explorative Analysen nahe, dass Kinder mit ADHS und gesunde Kinder unterschiedlichen Reifungsprozessen unterliegen. Auch scheint die chronische Einnahme der ADHS-Standardmedikation einen Einfluss auf die Hirnaktivität zu nehmen. Die Diskussion unserer Ergebnisse stellt zusammen mit der Offenlegung von Kritikpunkten an unserer sowie an vorhergehenden Studien einen wichtigen Ansatzpunkt zur Versuchsoptimierung in zukünftigen Arbeiten dar. Darüber hinaus ist weitere Forschung nötig, um detailliertere Kenntnisse über den Einfluss von Alter, Reifungsprozessen, chronischer MPH-Medikation, ADHS-Subtypen und dem Aufgabendesign zu erlangen. / It has been reported that children with attention-deficit/hyperactivity disorder (ADHD) have deficits in working-memory on a behavioural level. In addition numerous functional brain imaging studies have revealed a difference in prefrontal activation associated with working memory in comparison to healthy controls. So far it is unknown whether the prefrontal deficits depend on the components (object (OWM) and spatial visual working memory (SWM)) or processes (storage/rehearsal and central executive) of working memory. This study is the first to investigate working memory in children with ADHD by functional near-infrared spectroscopy. The main objectives were to replicate group differences in performance and prefrontal activation as well as to gain further information on the characteristic of prefrontal deficits in ADHD. The sample consisted of 19 children with ADHD combined type and 19 controls matched for age (8-15 years), sex, handedness, and intelligence. The working memory task included OWM and SWM and a control task. It was distinguished between two phases: storage- and matching phase. Prefrontal brain activity was measured by concentration changes of oxygenated and deoxygenated haemoglobin. Working memory performance was found to differ significantly for conditions. A typical prefrontal activation of working memory with highest amount in the dorsolateral region was detected only during the matching phase. No differences between groups were found in terms of performance and prefrontal activations. Different reasons were discussed. Explorative analyses indicate that there might be differences in the process of maturation between children with ADHD and controls. Moreover it appears that long-term medication with methylphenidate has an influence on brain activity. By considering the present data and reviewing the existing imaging literature on working memory in ADHD suggestions were given on how to optimize the design of experiment in the future. Further research is necessary to gain detailed knowledge about the influence of age, process of maturation, long-term medication and ADHD subtypes.

Ziel dieser Arbeit war es, die Möglichkeiten zur Verwendung des Auges bzw. der Augenvorderkammer als spektroskopische Zelle für nicht-invasive In-vivo-Messungen zu untersuchen. Dabei stand vor allem die Geräte-technische Umsetzung und die Entwicklung geeigneter Auswertestrategien im Vordergrund. In dieser Arbeit konnte gezeigt werden, dass die spektroskopische Untersuchung von Kammerwasser-Substanzen möglich ist. Durch den Einsatz der UV/VIS-Spektroskopie konnte Fluorescein in vivo bestimmt werden. Die Anwendung der NIR-Spektroskopie eignet sich vor allem zur Bestimmung von Glucose im Kammerwasser. Die Güte der Glucose-Bestimmung ist von verschiedenen Faktoren abhängig, wie z. B. dem verwendeten Gerät, den Parameter der Auswertung und der Temperatur. Für weitergehende Studien sollten daher die in dieser Arbeit aufgedeckten Probleme und Strategien beachtet werden. / The aim of this work was to determine the possibilities of using the human eye or more precisely the anterior chamber as spectroscopic cell for non-invasive in vivo measurements. The focus lay on the technical realization and the development of a suitable analysis strategy. This work showed that spectroscopic investigations of substances in the aqueous humor are possible. Fluorescein was determined in vivo by use of UV/VIS spectroscopy. NIR spectroscopy is a suited technique for the non-invasive glucose determination in the anterior chamber. The quality of the glucose determination depends on several factors, e. g. the instrument, the analysis parameters and the temperature. Any further studies on this field should take these factors into account.

Made available in DSpace on 2018-08-01T23:19:03Z (GMT). No. of bitstreams: 1 tese_10557_Resumo da Dissertação Final de Mestrado - Cíntia da Silva Araújo..pdf: 10136 bytes, checksum: b6b879a1bab26a1aab3fae6ab02ab32c (MD5) Previous issue date: 2018-02-27 / O café é um produto de interesse mundial. Sua bebida é uma das mais consumidas e apreciadas em diversas regiões do mundo. A composição físico-química dos grãos é influenciada por diversos fatores e tem interferência direta sobre as características finais apresentadas pela bebida. Os métodos de análises físico-químicas e sensorial empregados na análise de amostras de café são demorados e trabalhosos, fato esse que motiva a busca por formas alternativas de análise, podendo ser destacada a espectroscopia NIR como uma ferramenta promissora para esse fim. Neste contexto, o objetivo deste trabalho foi desenvolver modelos de calibração multivariada para determinar diversas propriedades físico-químicas e nota sensorial de amostras de café cultivadas em diversas regiões do estado do Espírito Santo de forma rápida e não destrutiva. As amostras de café foram submetidas às análises de umidade, sólidos solúveis totais, pH, acidez total titulável, açúcares totais e redutores, lixiviação de potássio, condutividade elétrica e compostos fenólicos totais. Os espectros sem pré-tratamento e pré-processados por diferentes técnicas foram utilizados para construção dos modelos de calibração, empregando o método de mínimos quadrados parciais por intervalo (iPLS). Os modelos desenvolvidos apresentaram boas correlações com os valores obtidos pelas análises convencionais, com destaque para a análise sensorial, cujo modelo obteve o maior valor de correlação entre todos os modelos desenvolvidos. Por outro lado, para a análise de umidade, o modelo apresentou viés significativo, indicando que este não foi adequado para estimativa do teor de umidade dos grãos. Foi verificado que os espectros NIR podem ser utilizados para determinação de diversas propriedades do café e que a utilização de técnicas de pré-processamento espectral melhorou a capacidade dos modelos de calibração em estimar os valores de referência.

Efficient delivery into cells is essential for many applications. However, cellular access of “cell-impermeable” molecules, such as drugs, sensors, proteins and oligonucleotides, can often be severely limited due to the plasma membrane which protects cells from unregulated influx of hydrophilic materials. In order to solve this issue, several physical techniques and bio-chemical products are today available. One of them is called peptoids (N-alkylglycines). These compounds are peptidomimetics which are resistant to enzymatic degradation, non-immunogenic and are readily prepared by an Fmoc chemical approach. Peptoids based on the "TAT"-peptide (RKKRRQRRR) offer rapid cellular uptake/delivery and low cytotoxicity. In this thesis, based on previous works using fluorescein-cationic peptoids, various fluorescent N-substitued glycines (lysine-like) were prepared by the monomer method followed by solid-phase synthesis. Their cellular uptakes in vitro into several cell lines (such as HeLa, B16F10, HEK293T and primary immune cells) were examined via flow cytometry and microscopy. The cellular delivery of small molecules mediated by the 9mer polymer achieved an efficient and rapid penetration. These results open up a vast number of applications for delivery of macromolecules using nonalysine-like peptoid. In order to demonstrate this ability, the nonalysinelike carrier was used to deliver various biopolymer molecules such as peptides, GFP protein and DNA (in collaboration with Dr. Stefano Caserta). In addition, thanks to the non-cytotoxicity of this cellular transpoter (MTT assays); experiments were carried out in vivo in mice using peptoids labelled near-infrared dyes. The first results have shown that the peptoid is not toxic for the mouse and does not block cell movements. These results allowed the use of 9mer-peptoid as a cellular tracking agent. Based on the development on antimicrobial peptides, the polylysine-like peptoid was also tested as an antibiotic. Recent experiments carried out in collaboration with Dr. Kevin Dhaliwal have revealed a new antimicrobial property of the peptoids. In vitro and in vivo studies have been carried out using both gram positive and negative bacteria. These results present a promising alternative to conventional antibiotics and antimicrobial peptides (AMPs).

Submitted by Jean Medeiros (jeanletras@uepb.edu.br) on 2016-03-09T13:08:05Z No. of bitstreams: 1 PDF - Demetrius José da Silva.pdf: 1875869 bytes, checksum: 1061e2217a110ec6fb9511ee004c9cde (MD5) / Approved for entry into archive by Secta BC (secta.csu.bc@uepb.edu.br) on 2016-07-21T21:00:30Z (GMT) No. of bitstreams: 1 PDF - Demetrius José da Silva.pdf: 1875869 bytes, checksum: 1061e2217a110ec6fb9511ee004c9cde (MD5) / Approved for entry into archive by Secta BC (secta.csu.bc@uepb.edu.br) on 2016-07-21T21:00:39Z (GMT) No. of bitstreams: 1 PDF - Demetrius José da Silva.pdf: 1875869 bytes, checksum: 1061e2217a110ec6fb9511ee004c9cde (MD5) / Made available in DSpace on 2016-07-21T21:00:39Z (GMT). No. of bitstreams: 1 PDF - Demetrius José da Silva.pdf: 1875869 bytes, checksum: 1061e2217a110ec6fb9511ee004c9cde (MD5) Previous issue date: 2014-02-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The analyzes of the physical properties of cotton fibers are made in HVI, which is characterized by the high cost of acquisition and maintenance, performs invasive analysis and can’t be used to evaluate chemical characteristics of the samples. The classical methods for analysis of cotton fibers are destructive, time consuming, laborious and require large amounts of reagents. The VIS and NIR spectroscopy appears as a good alternative for the analysis of white and naturally colored cotton fiber because this method maintains the integrity of the sample, can perform multiple measurements simultaneously and has a relatively low cost of acquisition if compared to HVI. This work aims to obtain calibration models for the prediction of physical properties of naturally colored cotton fiber using spectroscopy in the visible (VIS) and near-infrared (NIR) spectra, combined with multivariate analysis. A set of 72 independent fiber samples of six cotton cultivars were used, 24 of them of two with white fiber cultivars (BRS Aroeira and BRS 8H) and four with naturally colored fiber (BRS Topázio, BRS Verde, BRS Safira, and BRS Rubi) were analyzed. The samples were analyzed for fiber yield (FIB), upper half mean length (UHM), uniformity index (UNF), short fiber index (SFI), strength (STR), elongation (ELG), micronaire (MIC), maturity (MAT), count strength product (CSP) and wax content (WAX). A Tukey’s test and principal component analysis (PCA) were performed in the reference results. The reflectance spectra were preprocessed (Savitzky-Golay, MSC and SNV) before a partial least squares regression (PLS) calibration method and then obtained within a spectral range of 400-2500 nm. The Tukey’s test and PCA results were statiscally significative for SFI, ELG and WAX (this last one is more specifically for BRS Verde) parameters to all analyzed cultivars but BRS Topázio. The STR, UHM and CSP measurements stand out for the white fiber cultivars and have a negative relationship as compared to the MIC, MAT and FIB variables. In the set of evaluatedsamples, the SFI, ELG and WAX measurements tend to provide an inverse correlation with theother variables analyzed. The results of these measurements using HVI system, for white andnaturally colored fiber, are dependent of the composition and the wax content of the the fiber.The PLS calibration models with pre-processed spectra used for analysis of the principal properties which express cotton fiber quality were consistent with results obtained in the HVI system. The application of VIS-NIR spectroscopy and PLS calibration are strategies that providesatisfactory results for the analysis of cotton fiber with speed, accuracy and reliability. / As análises das propriedades físicas das fibras de algodão são feitas em sistema HVI, que se caracteriza pelo alto custo de aquisição e manutenção, realiza análises invasivas e não pode ser usado para avaliação de características químicas das amostras. Já os métodos clássicos para análise de fibras de algodão são destrutivos, demorados, laboriosos e exigem grandes quantidades de reagentes. A espectroscopia VIS-NIR surge como uma boa alternativa para a análise de fibras de algodão branco e naturalmente colorido, pois se trata de um método que mantem a integridade da amostra, permite várias determinações simultaneamente e tem um custo de aquisição relativamente baixo se comparado ao HVI. Pelo exposto, objetivou-se obter modelos de calibração para a predição de atributos da fibra de algodão naturalmente colorido utilizando espectroscopia na região do visível (VIS) e infravermelho próximo (NIR), aliadas a técnicas de análise multivariada. Um conjunto de 72 amostras independentes de seis cultivares de algodão foi utilizado, sendo 24 delas de duas cultivares de fibra branca (BRS 8H e BRS Aroeira) e 48 amostras de quatro cultivares de fibra naturalmente colorida (BRS Topázio, BRS Verde, BRS Safira e BRS Rubi). As amostras foram analisadas para as propriedades de rendimento de fibra (FIB), comprimento médio (UHM), uniformidade (UNF), índice de fibras curtas (SFI), resistência (STR), alongamento à ruptura (ELG), micronaire (MIC), maturidade (MAT), índice de fiabilidade (CSP) e teor de cera (WAX). Os resultados de referência foram submetidos ao Teste de Tukey e análise de componentes principais (PCA). Os espectros de reflectância foram obtidos na faixa espectral de 400 a 2500 nm, os quais foram pré-processados (Savitzky-Golay, MSC e SNV) antes da calibração pelo método de regressão por Mínimos Quadrados Parciais (PLS). Constatou-se significância entre as variáveis SFI, ELG e WAX, as duas primeiras para as cultivares de fibra naturalmente coloridas, com exceção da BRS Topázio, e a última para a cultivar BRS Verde. As medidas de STR, UHM e CSP destacam-se para as cultivares de fibra branca e possuem relação negativa entre as variáveis MIC, MAT e FIB. No conjunto de amostras avaliadas, as medidas de SFI, ELG e WAX tendem a fornecer correlação inversa com as demais varáveis analisadas. Os resultados dessas medidas em sistema HVI, tanto em fibra branca e naturalmente colorida, são dependentes da composição da fibra para os teores de cera. Os modelos de calibração por PLS, em espectros pré-processados, para as principais propriedades que expressam a qualidade de fibras de algodão foram compatíveis com os resultados obtidos em sistema HVI. A aplicação da espectroscopia VIS-NIR e calibração por PLS são estratégias que fornecem resultados satisfatórios para análise de fibra de algodão com rapidez, precisão e confiabilidade.