In this study, the performances of the optical sensors and instruments carried on both ground-based and airborne platforms were evaluated for monitoring crop growing status, detecting the vegetation response to aerial applied herbicides, and identifying crop nitrogen status. Geostatistical analysis on remotely sensed data was conducted to investigate spatial structure of crop canopy normalized difference vegetation index and multispectral imagery. A computerized crop monitoring system was developed that combined sensors and instruments that measured crop structure and spectral data with a global positioning system. The integrated crop monitoring system was able to collect real-time, multi-source, multi-form, and crop related data simultaneously as the tractor-mounted system moved through the field. This study firstly used remotely sensed data to evaluate glyphosate efficacy on weeds applied with conventional and emerging aerial spray nozzles. A weedy field was In this study, the performances of the optical sensors and instruments carried on both ground-based and airborne platforms were evaluated for monitoring crop growing status, detecting the vegetation response to aerial applied herbicides, and identifying crop nitrogen status. Geostatistical analysis on remotely sensed data was conducted to investigate spatial structure of crop canopy normalized difference vegetation index and multispectral imagery. A computerized crop monitoring system was developed that combined sensors and instruments that measured crop structure and spectral data with a global positioning system. The integrated crop monitoring system was able to collect real-time, multi-source, multi-form, and crop related data simultaneously as the tractor-mounted system moved through the field. This study firstly used remotely sensed data to evaluate glyphosate efficacy on weeds applied with conventional and emerging aerial spray nozzles. A weedy field was set up in three blocks and four aerial spray technology treatments were tested. Spectral reflectance measurements were taken using ground-based sensors from all the plots at 1, 8, and 17 days after treatment. The results indicated that the differences among the treatments could be detected with spectral data. This study could provide applicators with guidance equipment configurations that can result in herbicide savings and optimized applications in other crops. The main focus of this research was to apply sensor fusion technology to ground-based and airborne imagery data. Experimental plots cropped with cotton and soybean plants were set up with different nitrogen application rates. The multispectral imagery was acquired by an airborne imaging system over crop field; at the same period, leaf chlorophyll content and spectral reflectance measurements were gathered with chlorophyll meter and spectroradiometer at canopy level on the ground, respectively. Statistical analyses were applied on the data from individual sensor for discrimination with respect to the nitrogen treatment levels. Multisensor data fusion was performed at data level. The results showed that the data fusion of airborne imagery with ground-based data were capable of improving the performance of remote sensing data on detection of crop nitrogen status. The method may be extended to other types of data, and data fusion can be performed at feature or decision level.

Different kinds of nanoparticles are widely used in optoelectronic and photovoltaic applications to harvest light to increase efficiency of devices. ETS-10, which is a synthetic microporous material consisting of &ndash / Ti-O-Ti-O-Ti- wires that run in the crystal in a and b directions, has been of interest in such applications due to its unique properties. In the current study, the synthesis conditions of ETS-10 were investigated in order to obtain pure ETS-10 crystals with the desired morphology. For this purpose, ETS-10 crystals were synthesized using different molar compositions. The effects of several synthesis parameters on the obtained products were investigated. Furthermore, ETS-10 thin films were prepared on ITO glass substrates using secondary growth of ETS-10 for the first time. The orientation of the -Ti-O-Ti-O-Ti- wires inside ETS-10 were explored by preparing several ETS-10 films on the ITO glass substrates using secondary growth of ETS-10 multilayers with a partial a(b)-out-of-plane preferred crystal orientation. This orientation can be desirable for the advanced applications of ETS-10 films. Afterwards, silver nanoparticle modified ETS-10 crystals were prepared and characterized in detail to understand the interaction of silver nanoparticles with the synthesized ETS-10 crystals. For this purpose, ETS-10 in the as-prepared and silver nanoparticle containing forms have been characterized using, XRD, ICP-OES, SEM, HR-TEM, N2 Adsorption, XPS, and UV/VIS spectroscopy. In order to investigate the optical properties of the silver modified ETS-10, transmittance-reflectance measurements were carried out. In general, it is believed that all steps necessary for the preparation of ETS-10 films and preliminary steps for investigating ETS-10 for future photovoltaic applications were determined.

Mid-infrared (MIR) spectroscopy has been recognized as an important analytical technique, and is widely applied for qualitative and quantitative analysis of materials with an increasing interest in addressing complex organic or biologic constituents. In the presented thesis, (a) the fundamental principles for IR spectroscopic applications via in vivo catheters in combination with multivariate data analysis technique were developed, and (b) the combination with a second analytical technique ¨C scanning electrochemical microscopy (SECM) - for enhancing the information obtained at complex or frequently changing matrices was demonstrated. The first part of this thesis focused on the combination of different MIR measurment techniques with specific focus on evanescent field absorption spectroscopy along with multivariate data analysis methods, for the discrimination of atherosclerotic and normal rabbit aorta tissues. Atherosclerotic and normal rabbit aorta tissues are characterized by marked differences in chemical composition governed by their water, lipid, and protein content. Strongly overlapping infrared absorption features of the different constituents and the complexity of the tissue matrix render the direct evaluation of molecular spectroscopic characteristics obtained from IR measurements challenging for classification. We have successfully applied multivariate data analysis and classification techniques based on principal component analysis (PCA), partial least squares regression (PLS), and linear discriminant analysis (LDA) to IR spectroscopic data obtained by infrared attenuated total reflectance (IR-ATR) measurements, reflection IR microscopy, and a recently developed IR-ATR catheter prototype for future in vivo diagnostic applications. Training and test data were collected ex vivo at atherosclerotic and normal rabbit aorta samples. The successful classification results at atherosclerotic and normal aorta samples utilizing the developed data evaluation routines reveals the potential of IR spectroscopy combined with multivariate classification strategies for in vitro, and ¨C in future - in vivo applications. The second part of this thesis aimed at the development of a novel multifunctional analytical platform by combining SECM with single-bounce IR-ATR spectroscopy for in situ studies of electrochemically active or electrochemically induced processes at the IR waveguide surface via simultaneous evanescent field absorption spectroscopy. The utility of the developed SECM-IR-ATR platform was demonstrated by spectroscopically monitoring microstructured polymer depositions induced via feedback mode SECM experiments using a 25μm Pt disk ultramicroelectrode (UME). The surface of a ZnSe ATR crystal was coated with a thin layer of 2,5-di-(2-thienyl)-pyrrole (SNS), which was then polymerized in a Ru(bpy) ₃ ² ⁺-mediated feedback mode SECM experiment. The polymerization reaction was simultaneously spectroscopically monitored by recording the absorption intensity changes of specific IR bands characteristic for SNS, thereby providing information on the polymerization progress, mechanism, and level of surface modification. Furthermore, a novel current-independent approach mechanism for positioning the UME in aqueous electrolyte solution was demonstrated by monitoring IR absorption changes of borosilicate glass (BSG) shielding the UME, and of water within the penetration depth of the evanescent field.

<p>The work in this licentiate thesis examines the adsorption of polyelectrolyte multilayers (PEM) onto wood fibres as a new way to influence the properties of the fibre surfaces and hence the fibres. Fundamental aspects of PEM formation on wood fibres have been studied, and discussed in terms of paper strength and wood fibre wettability.</p><p>PEMs have been formed from three different polymer systems: 1) two strong polyelectrolytes (i.e., fully charged over a wide pH range), polydimethyldiallylammonium chloride (PDADMAC) and polystyrene sulphonate (PSS); 2) polyethylene oxide (PEO) and polyacrylic acid (PAA), formed at low pH and held together by hydrogen bonding; and 3) two weak polyelectrolytes, polyallylamine hydrochloride (PAH) and polyacrylic acid (PAA). The PEMs formed from PDADMAC/PSS and PEO/PAA were studied using Stagnation Point Adsorption Reflectometry (SPAR), with SiO2 as the substrate. This was done to establish the formation of PEMs and, using PDADMAC/PSS, also to predict the influence of salt concentration during PEM formation. The amount of PDADMAC/PSS adsorbed was found to increase with salt concentration up to approximately 0.1 M NaCl. The formation of PEMs from PAH/PAA has already been studied in terms of structure; amount adsorbed, and influence on paper strength.</p><p>Sheets were formed from fibres treated with either PDADMAC/PSS or PEO/PAA PEMs and tested to determine paper tensile strength. Both PEM systems increased the tensile index and strain at break in the range of 100% when approximately 10 layers had been adsorbed. After several PEM layers had been adsorbed, the sheets made of fibres treated with PDADMAC/PSS differed in tensile strength depending on the polymer adsorbed in the outermost layer. A higher tensile strength was detected when PDADMAC rather than PSS was adsorbed in the outermost layer. Sheets made of fibres treated with PEO/PAA displayed a linear increase in strength, independent of which polymer that was adsorbed in the outermost layer.</p><p>The amount of adsorbed PDADMAC/PSS, as analysed using nitrogen and sulphur analysis, respectively, increased linearly, but with a higher amount adsorbed in the first layer. A comparison of the adsorption onto the SiO₂-surfaces (SPAR-measurements) and fibres shows some differences. This is apparent both regarding the adsorption in the first layer and in the change in adsorbed amount with salt concentration. Despite this, one can conclude that SiO₂ and wood fibres show very similar trends, and that SiO₂can be used as a convenient model surface in predicting PEM formation on wood fibres.</p><p>Individual fibres were also partially treated using a Dynamic Contact Angle Analyser, and the treated and untreated parts were analysed in terms of wettability and surface structure. The differences in wettability are significant, depending on the polymer system used and, with PAH/PAA PEMs, the pH strategy show a large influence in wettability. PDADMAC/PSS and PAH/PAA PEMs both had a large influence on wettability, depending on the polymer adsorbed in the outermost layer, wettability being lower when the cationic polymer was adsorbed in the outermost layer. With the PEO/PAA system, however, the polymer adsorbed in the outermost layer caused no detectable difference. These results, when compared against the paper strength results, indicate that the strongest sheets are formed of the fibres with the lowest wettability. This may be explained in terms of wet adhesion: since the fibre networks are formed in water, lower wettability would give a stronger force between the fibres during consolidation, resulting in a greater contact area and thus probably a stronger dry adhesion between the fibres in the formed sheet. This is furthermore also supported by wet adhesion measurements using Atomic Force Microscopy where PEMs formed from PAH/PAA, show that the pull-off force is increased when PAH is adsorbed in the outermost layer, compared to when PAA is adsorbed in the outermost layer.</p> / <p>Denna licentiatavhandling behandlar adsorption av polyelektrolytmultiskikt (multiskikt) på cellulosafibrer som ett nytt sätt att påverka en fibers ytegenskaper. Grundläggande förutsättningar för bildandet av multiskikt på fibrer diskuteras i termer av pappersstyrka och fibervätning.</p><p>Multiskikt har bildats med hjälp av tre olika polymerkombinationer; 1.) två starka polyelektrolyter, polydiallyldimetylammoniumklorid (PDADMAC) och polystyrensulfanat (PSS), 2.) polyetylenoxid (PEO) och polyakrylsyra (PAA), adsorberade vid lågt pH och sammanhållna av icke elektrostatiska vätebindningar, och 3.) två svaga polyelektrolyter, polyallylaminhydroklorid (PAH) och PAA. Uppbyggnaden av multiskikt bestående av PDADMAC/PSS och PEO/PAA på kiseloxid studerades med Stagnationspunktsreflektometri (SPAR) för att undersöka att uppbyggnad av PEM skett, samt att studera hur uppbyggnaden påverkas av koncentrationen NaCl i polymerlösningen. Försöken visade att den adsorberade mängden PDADMAC/PSS ökade med saltkoncentrationen upp till 0,05-0,1 M NaCl. Uppbyggnaden av multiskikt bestående av PAH/PAA är sedan tidigare studerad undersöks därför inte specifikt i detta arbete.</p><p>Laboratorieark tillverkades av fibrer som behandlats med multiskikt bestående av PDADMAC/PSS, respektive PAH/PAA. Fysikalisk pappersprovning av arken visade för båda systemen en ökning med cirka 100 % i dragindex för ark som tillverkats av fibrer som behandlats med cirka tio lager, jämfört med ark som tillverkats av icke-behandlade fibrer. Ark tillverkade från PDADMAC/PSS-behandlade fibrer visade att när 5-7 lager adsorberats, ett högre dragindex då PDADMAC adsorberats i det yttersta lagret, jämfört med då PSS adsorberats i det yttersta lagret. Ark tillverkade från fibrer behandlade med PEO/PAA visade ingen skillnad i dragindex beroende av vilken polymer som adsorberats i det yttersta lagret.</p><p>Den adsorberade mängden PDADMAC/PSS på fibrerna bestämdes med hjälp av kväve- respektive svavelanalys. Den adsorberade mängden polymer ökad linjärt som en funktion av antalet adsorberade lager, men med en högre adsorberad mängd i det första lagret. Dessa resultat har jämförts med den adsorberade mängden för multiskikt uppbyggda med SPAR på kiseloxid. Jämförelsen visade att det finns skillnader i uppbyggnaden mellan skikt byggda på kiseloxid och fibrer, men att kiseloxid med god tillförlitlighet kan användas som modellyta för att förutsäga generella trender för adsorptionen av samma polymersystem på cellulosafibrer.</p><p>Multiskikt har också bildats på enskilda fibrer med hjälp av en dynamisk kontaktvinkelmätare (DCA). Genom att behandla en del av en fiber, och jämföra den behandlade delen med den obehandlade delen på samma, kan ett multiskikts inverkan på fiberns ytstruktur och vätningsegenskaper studeras. De olika polymersystemen visade en avsevärd skillnad i förmågan att påverka en fibers vätningsegenskaper. För fibrer behandlade med PAH/PAA är också pH av stor betydelse för graden inverkan på fiberns vätningsegenskaper. Fibrer behandlade med PDADMAC/PSS och PAH/PAA, visade en sämre vätningsförmåga då den katjoniska polymeren adsorberats i det yttersta lagret, och vice versa. För enskilda fibrer behandlade med PEO/PAA, kunde inte konstateras någon skillnad beroende av vilken polymer som adsorberats i det yttersta lagret.</p><p>Vid en jämförelse mellan vätningsförmåga och pappersstyrka kan konstateras att de ark som visade den högsta styrkan tillverkats av fibrer där den lägsta vätningsförmågan har kunnat konstateras. Denna skillnad kan diskuteras med utgångspunkten i att en lägre vätningsförmåga resulterar i en högre våt adhesion och därmed en starkare interaktion mellan de polymerbehandlade ytorna i vått tillstånd. Det föreslås i avhandlingen att den ökade kraft som detta resulterar i vid bildandet av en fiber-fiberfog ger upphov till en högre kontaktarea och därmed, förmodligen, också en högre torr adhesion. Kraftmätningar i vått tillstånd för behandlade kiselmodellytor med hjälp av atomkraftsmikroskopi (AFM) har för PAH/PAA visat att den våta adhesionen är högre då PAH är adsorberats i det yttersta lagret, jämfört med då PAA adsorberats i det yttersta lagret. Detta stödjer hypotesen att en lägre vätning gynnar uppkomsten av en stark fiber-fiberfog.</p>

Thesis (Ph. D.)--University of Missouri-Columbia, 1999. / Typescript. Vita. Includes bibliographical references (leaves 136-142). Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 1999. / Typescript. Vita. Includes bibliographical references (leaves 136-142). Also available on the Internet.

Understanding material behavior under extreme conditions is an important area of research in physics and material science. One method to study the behavior of materials under these conditions is to drive a strong shock wave through a material and watch its response. In many cases the material response is complicated by phase transitions such as lattice restructuring (Barker 1975; Mabire and Hereil 2000; Swift, Tierney et al. 2005) and melting (Asay 1975; Elias, Chapron et al. 1988; Werdiger, Eliezer et al. 1999; Mabire and Hereil 2000; Swift, Tierney et al. 2005). To study these dynamics we are using lasers in high time resolution pump-probe experiments to develop a real time diagnostic on the phase of a shocked material. This technique enables probing of the entire phase history of a material as it shock compresses and releases. In addition to linear reflectivity and ultra-fast 2D displacement interferometry, we developed a melting diagnostics based on the non-linear optical technique of third harmonic generation (THG) using a circularly polarized laser pulse. This diagnostic resolves the less than 300 fs melting transition of laser excited Si and GaAs, and it also detects a response in shock compressed silicon. Our results show that Si remains crystalline during compression of an elastic 100 kbar shock wave. Results from Si shocked to higher pressures (> 300 kbar) indicate a decrease in THG, suggesting some level of disordering or unexplained phase change. / text

This dissertation focuses on the development of algorithms for analyzing and modeling of the signals from optical spectroscopy. This dissertation is motivated by the detection of oral cancer, but some of the methods developed can be generalized to epithelial cancers of other sites. Two main topics are covered in this dissertation: Analysis and Modeling. For analysis, the focus is on developing algorithms to make diagnostic predictions. The analysis methods are empirically tested using an oral cancer dataset. Statistical analyses show that polarized reflectance spectroscopy has the potential to aid screening and diagnosis of oral cancer. Also, a novel adaptive windowing technique is developed to extract spectral features with fewer windows that retain the diagnostic information. For modeling, a Monte Carlo model simulating light-tissue interactions is presented to aid in the design of diagnostic instrumentation. / text

This thesis describes the development of an empirical model of focus beam reflectance measurements (FBRM) and the application of the model to monitoring batch cooling crystallization and extracting information on crystallization kinetics. Batch crystallization is widely used in the fine chemical and pharmaceutical industries to purify and separate solid products. The crystal size distribution (CSD) of the final product greatly influences the product characteristics, such as purity, stability, and bioavailability. It also has a great effect on downstream processing. To achieve a desired CSD of the final product, batch crystallization processes need to be monitored, understood, and controlled. FBRM is a promising technique for in situ determination of the CSD. It is based on scattering of laser light and provides a chord-length distribution (CLD), which is a complex function of crystal geometry. In this thesis, an empirical correlation between CSDs and CLDs is established and applied in place of existing first-principles FBRM models. Built from experimental data, the empirical mapping of CSD and CLD is advantageous in representing some effects that are difficult to quantify by mathematical and physical expressions. The developed model enables computation of the CSD from measured CLDs, which can be followed during the evolution of the crystal population during batch cooling crystallization processes. Paracetamol, a common drug product also known as acetaminophen, is selected as the model compound in this thesis study. The empirical model was first established and verified in a paracetamol-nonsolvent (toluene) slurry, and later applied to the paracetamol-ethanol crystallization system. Complementary to the FBRM measurements, solute concentrations in the liquid phase were determined by in situ infrared spectra, and they were jointly implemented to monitor the crystallization process. The framework of measuring the CSD and the solute concentration allows the estimation of crystallization kinetics, including those for primary nucleation, secondary nucleation, and crystal growth. These parameters were determined simultaneously by fitting the full population balance model to process measurements obtained from multiple unseeded paracetamol-ethanol crystallization runs. The major contributions of this thesis study are (1) providing a novel methodology for using FBRM measurements to estimate CSD; (2) development of an experimental protocol that provided data sets rich in information on crystal growth and primary and secondary nucleation; (3) interpretation of kinetics so that appropriate model parameters could be extracted from fitting population balances to experimental data; (4) identification of the potential importance of secondary nucleation relative to primary nucleation. The protocol and methods developed in this study can be applied to other systems for evaluating and improving batch crystallization processes.

Στη διδακτορική διατριβή μελετώνται πέντε διαφορετικά προβλήματα που συναντώνται στη δημιουργία ενός συστήματος εκτίμησης ανακλαστικότητας χρώματος αντικειμένων και ποιοτικού ελέγχου έγχρωμων επίπεδων επιφανειών με σχέδια. Το πρώτο πρόβλημα αφορά στην εξαγωγή της απόκρισης φωτεινότητας της κάμερας που θα χρησιμοποιηθεί στο σύστημα. Για την εκτίμησή της προτάθηκαν τέσσερις μέθοδοι (δύο παραμετρικές και δύο μη παραμετρικές) που κάνουν χρήση των δεδομένων πολλαπλών εικόνων τυχαίων σκηνών. Η απόκριση φωτεινότητας εκτιμάται με χρήση πρωτότυπων συστημάτων εξισώσεων υπό περιορισμούς. Το δεύτερο πρόβλημα αφορά την εκτίμηση της φασματικής απόκρισης της κάμερας. Προτείνεται μία νέα μέθοδος που χρησιμοποιεί μοντέλο αθροίσματος κανονικών κατανομών και γενετικό αλγόριθμο. Η μέθοδος αυτή παρουσιάζει ανώτερη απόδοση σε σχέση με άμεσα ανταγωνιστικές μεθόδους στην εκτίμηση των φασματικών αποκρίσεων. Το τρίτο πρόβλημα αφορά επιλογή οπτικών φίλτρων από διαθέσιμο σύνολο για την κατασκευή πολυκαναλικού συστήματος εκτίμησης της φασματικής ανακλαστικότητας αντικειμένων. Προτείνονται νέες προσεγγίσεις με ανώτερη ακρίβεια φασματικής ανακατασκευής ανακλαστικοτήτων σε σχέση με ανταγωνιστικές μεθόδους. Το τέταρτο πρόβλημα αφορά στην επίτευξη χρωματικής ισοστάθμισης. Προτείνεται μία νέα παραδοχή μεγιστοποίησης της αντίθεσης στο κανάλι της φωτεινότητας. Με βάση την παραδοχή αυτή προτείνονται νέες μέθοδοι χρωματικής ισοστάθμισης και συγκρίνονται με υπάρχουσες στη βιβλιογραφία. Τα αποτελέσματα είναι συγκρίσιμα ή και ανώτερα ανταγωνιστικών μεθόδων. Το πέμπτο πρόβλημα αφορά στη δημιουργία συστήματος ανίχνευσης σφαλμάτων σε έγχρωμες επίπεδες επιφάνειες. Προτείνεται ένα πρωτότυπο σύστημα εντοπισμού σφαλμάτων που βασίζεται στην σύγκριση διανυσμάτων χαρακτηριστικών τοπικών ιστογραμμάτων σε πολλαπλά επίπεδα ανάλυσης και χρωματικά κανάλια. Τα διανύσματα χαρακτηριστικών είναι ανεξάρτητα από περιστροφή και μετατόπιση και ανεκτικά σε παραμορφώσεις. Η μέθοδος απαιτεί την ύπαρξη δειγμάτων αναφοράς για εκπαίδευση. Με έναν πρωτότυπο αλγόριθμο εντοπισμού σφαλμάτων, που χρησιμοποιεί τα δεδομένα που αποκτήθηκαν από τα δείγματα αναφοράς, γίνεται εντοπισμός των σφαλμάτων στις εικόνες επισκόπησης. Το σύστημα αξιολογείται όσον αφορά στην απόδοσή του χρησιμοποιώντας μία βάση δεδομένων εικόνων η οποία περιέχει τεχνητά σφάλματα και δημιουργήθηκε για το σκοπό αυτό. / This dissertation analyzes five different problems on the development of an image based reflectance reconstruction system for defect detection on colour patterned planar objects. The first problem involves the estimation of the camera’s photoquantimetric response. Four new methods are proposed (two parametric and two non-parametric) using multiple images of the same static scene. The photoquantimetric response is estimated by the use of a novel formulation of linear systems with restrictions. The second problem refers to the estimation of the camera’s spectral response. Through the use of a sum of Gaussian model combined with genetic algorithms a new formulation is achieved. This new method shows improved performance compared to previous approaches. The third problem involves the selection of a subset of optical filters from an available set for the development of a multispectral reflectance reconstruction system. New approaches are proposed based on statistical features of the system responses providing better reflectance reconstruction accuracy in comparison to previous methods. The fourth problem refers to colour constancy. A novel assumption is proposed based on contrast maximization in the intensity channel. New methods based on this assumption are proposed. These new methods show comparable or even superior performance to existing colour constancy methods. The fifth problem involves the development of a defect detection system for coloured patterned planar surfaces. A novel defect detection system is proposed based on the comparison of statistical local feature vectors at multiple scales of resolution. The features used are rotation and translation invariant and robust to non-linear deformations. The system requires the existence of defect free reference patterns. A novel defect detection algorithm is proposed and tested on a database especially created for the task with satisfying results.