In recent years, there have been several research endeavors to increase the ability to identify and quantify special nuclear material in field measurements. These have included both gamma spectroscopy and neutron coincidence systems that are portable and work in a variety of environments. In this work, a Monte Carlo Neutral Practicle X (MCNPX) model was used to design an instrument that includes four gamma detection slabs placed within four neutron detection slabs. The combination of gamma spectroscopy and neutron coincidence counting in a single instrument allows for direct measurement of plutonium (Pu) mass without need for assumptions or operator declarations. A combined neutron-gamma instrument was designed for use in characterizing and quantifying Pu in field samples. This detector consists of a plastic scintillator containing LaBr3 nanoparticles and a polyethylene slab containing four 3He tube detectors. The system was tested via simulation with MCNPX for four Pu samples of known quality and quantity. These samples had masses ranging from 100-300 g of Pu. It was found that the designed detector system could be used to determine 240Pu-effective mass to within 3.5% accuracy and to characterize the isotopic content of the Pu to within 2% accuracy for all isotopes except for 238Pu and 242Pu. The system could determine 238Pu isotopic content to within 14% accuracy but is completely unable to determine 242Pu content. This system has the ability to Four Plutonium (Pu) samples of known quantity were modeled and tested to determine what data was available from each individual signature. Each model included a separate MCNPX deck for each individual isotope that contributes to the gamma signature in photon mode and a spontaneous fission and (alpha,n) deck for the neutron signature. The first three samples were used to create spectrums and efficiency curves for each odd isotope as well as for a Pu effective mass for the neutron signature. The data from these simulations were then used to identify the isotopics in the fourth sample to within acceptable accuracy. From this data, a total Pu mass was obtained as well as an ability to determine the ratio of (alpha,n) to spontaneous fission neutrons without additional simulations. This provides a new method to detect and identify the Pu content within a sample without producing requiring supplemental additional information since isotopics can be determined with the combined use of the gamma and neutron systems.

No / Fourier transform (FT) Raman spectroscopy was evaluated as a non-destructive analytical tool for assessing the degradative state of archaeological and forensic hair samples. This work follows the successful application of FT-Raman spectroscopy to studies of both modern hair and ancient keratotic biopolymers, such as mummified skin. Fourteen samples of terminal scalp hair from 13 disparate depositional environments were analysed for evidence of structural alteration. Degradative change was evidenced by alteration to the amide I and III modes near 1651 and 1128 cm−1, respectively, and loss of definition to the (CC) skeletal backbone and the impact of environmental contaminants was noted.

Due to the frequent use of plastics in daily life, encountering microplastics as pollution and trace evidence in forensic investigations is a common occurrence. Nylons are a plastic class known to be strong and durable, and they are used in a variety of products. Nylon is also a popular choice among 3D printing materials, and its strength and durability lend themselves to printing tools like keys and firearms. The analysis of microplastics is typically performed using any combination of microscopy, infrared spectroscopy, Raman spectroscopy, and mass spectrometry. Nylons are known to have fluorescent impurities created during the polymer’s synthesis and processing, so this work set out to develop a method to analyze nylon microplastics non-destructively using room-temperature fluorescence spectroscopy. By analyzing impurities in the sample, fluorescence spectroscopy can provide additional information about the microplastic’s source that other non-destructive methods do not. Excitation-emission matrices, excitation and emission spectra, and synchronous fluorescence spectra were collected from pellets of four different nylons. Using these spectra, all nylons could be distinguished from one another. A trace evidence simulation was then performed with fragmented pellets and a 3D printed key, and the trace microplastics were shown to have spectra that were consistent with those of the bulk plastic. This method was then improved by applying chemometric algorithms to the fluorescence data. Fluorescence spectra, excitation spectra, and excitation-emission matrices collected from Nylon 6 and Nylon 6/12 were found to be indistinguishable by visual comparison. Using synchronous fluorescence spectra from the two nylons in conjunction with Principal Component Analysis and Common Dimension – Partial Least Squares – Discriminant Analysis, the two nylons could be fully discriminated. Overall, this work presents a powerful new method to non-destructively analyze nylon microplastics and generate more reliable conclusions about the source of the microplastic than current methods alone.

Non-destructive methods of material interrogation are used to locate hidden explosives and thwart terrorism attempts. In one such method materials are bombarded with neutrons which react with the nuclei of the atoms within causing a de-excitation process emitting a gamma-ray. The spectrum displayed by the collection of these gamma-rays gives valuable information regarding the material’s elemental make-up. It has been hypothesized that gamma-rays from neutron-induced gamma-ray reactions on light elements with atomic numbers less than 20, including most of the gamma-rays of interest in explosives detection, are Doppler-broadened. This thesis focuses on the gamma ray spectra from the 4438 keV gamma ray in the 12C (n, n’γ) reaction wherein Doppler broadening was investigated. A graphite sample was exposed to 14 MeV neutrons and the 12C gamma ray spectra collected using an HPGe detector positioned at four different angles with respect to the neutron beam; near 00, 450, 900 and 1350. No other experimental parameter was changed. The resultant gamma ray spectra indicated Doppler broadening had occurred.

Ce manuscrit traite de l'étude métrologique d'un spectromètre Terahertrz (THz), de la caractérisation et de la quantification de produits pulvérulents par spectroscopie THz. Le sujet a été orienté afin de fournir les études préliminaires nécessaires à une thématique visant la détection de pesticides sur les aliments, à savoir la caractérisation métrologique de l'appareil (études de répétabilité, sensibilité...) ainsi que la faisabilité de la quantification de produits et l'application de méthodes chimiométriques lors du prétraitement des spectres. La thèse est ordonnée autour de trois publications. La première publication consiste en une revue de littérature servant à faire le point sur les applications concrètes existant en spectroscopie THz. La seconde porte sur la première partie de notre travail, à savoir la caractérisation métrologique du spectromètre THz sur lequel nous avons effectué nos mesures. Enfin, la troisième porte sur l'aspect quantification de la spectroscopie THz et la possibilité d'appliquer les mêmes principes et techniques chimiométriques qu'en spectroscopie infrarouge. / This manuscript concerns the metrological study of a Terahertz (THz) spectrometer, the characterization and the quantification of powder products by THz spectroscopy. The subject has been aimed to give preliminary analysis to a wider thematic of pesticides detection on aliments, which implies the metrological characterization of the device (repeatability, sensitivity...) and the quantification feasibility of these products and the application of chemometrics methods for spectral pretreatment. The thesis is organized around three publications. The first publication is a literature review, which aims to list but a few of the concrete applications of THz spectroscopy. The second one concerns the metrological characterization of the THz spectrometer we worked on. Lastly, the third one deals with the quantification aspect of THz spectroscopy and the possibility of using the same principles and chemometrics techniques that are used in infrared spectroscopy.

<p>Recently, energy storage systems have become more focused towards sustainable energy sources like LIBs due to attractive attributes like high energy density and volumetric density which make them extremely competitive compared to other energy sources for many portable and non-portable applications (smartphones, eVTOLs, stationary storage systems, electric vehicle and so on). Longer cycling stability, capacitance retentive power, lower self-discharge rate and high voltage window are qualitative features in LIB. Even though LIBs are rechargeable energy storage systems, all cells decay and degrade over time causing capacity and power fade due to a number of factors such as manufacturing defects, usage outside the normal operating conditions, and other abuse conditions like overcharge, over-discharge and indentation. This work presents a systematic investigation of several off-nominal conditions which are typically observed in LIBs such as overcharge, over-discharge, nail indentation, periodic overcharge, and over-discharge in order to form a comparative analysis on the effect of each of these conditions on cycle life aging, morphological changes on the cell components and also to evaluate potential internal short circuit (ISC) mechanisms. The cell failure mechanism induced by each condition and its negative impact on the electrochemical performance has been rigorously analyzed in this work based on the proper protocols. The correlation of the galvanostatic performance with the morphological change of the individual electrodes was also scrutinized under SEM and EDS to demarcate the severity of the defect into Li-ion cells. The practical off-nominal condition analysis of LIB will pave the way for more reliable cell functioning and recommendations to be considered to effectively analyze these off-nominal conditions. The analysis was divided into two parts; 1) curve-based analysis which included capacity fade, internal resistance, Incremental & Differential capacity analysis and EIS analysis 2) disassembly-based analysis which consisted of post-mortem visual inspection, morphology-based analysis using electron microscopy and composition analysis. From the capacity fade and IR evolution study, it was observed that periodic off-nominal conditions exhibited the highest rate of capacity fade and the greatest increase in DC internal resistance consistently. The least rate of capacity loss was shown by overcharged and no defect cells and a similar trend for DCIR values as well indicating that there was a positive correlation between capacity fade and internal resistance evolution. From the EIS study a slightly different trend was observed with the overcharged cell exhibiting the highest ohmic resistance and the no defect cell XV </p> <p>the least indicating ORI as an aging mechanism in overcharged and periodic overcharge/over-discharged cells. Another interesting observation was that the highest change in change transfer resistance was shown by over-discharged cell followed by nail-indented and overcharged cells and the least for cells subjected to periodic off-nominal conditions. This was attributed to a large amount of delamination caused by particle cracking in no defect cells causing LAM in these cells, lithium plating in Overcharged, copper current collector dissolution in over-discharged cells which resulted in LLI as the primary aging mechanism in these cells. This was further confirmed by ICA-DVA curve analysis at various capacity fades, postmortem inspection and SEM-EDS analysis. The periodic overcharged cells underwent a combination of degradation mechanisms including LAM from delamination, LLI through lithium deposition on the separators and Contact loss due to electrolyte vaporization causing active material adhesion on the separator and vice versa. The last degradation mechanism exacerbated the rate of increase of internal resistance by blocking pathways for Li+ ion diffusion. To summarize, while no defect and nail-indented cells exhibited primarily one aging mechanism (ORI) other cells exhibited a combination of degradation modes and the decoupling of these modes became increasingly indistinguishable for the cells subjected to periodic off-nominal conditions. Interestingly, no manifestation of soft or hard Internal short circuits was observed in the tested cells. However, it should be noted that for the periodic overcharged cells which underwent excessive lithium plating on the separators and charring of electrodes, dendrite formation could potentially have caused ISC upon further cycling. This cements the fact that periodic off-nominal conditions exacerbate the possibility of sudden failures and accelerate degradation in Li-ion cells. </p>

[pt] Este trabalho tem como objetivo efetuar um estudo arqueometalúrgico de objetos ferrosos e não-ferrosos resgatados de sítios históricos do Rio de janeiro. A pesquisa experimental desenvolveu uma metodologia de análise utilizando-se de técnicas destrutivas como Microscopia Ótica (MO), Microscopia Eletrônica de Varredura (MEV), Microscopia Eletrônica de Transmissão e não destrutivas como Fluorescência de Raio X (FRX) e Emissão de Raios-X por Indução de Partículas (PIXE). Os objetos foram analisados com o intuito de caracterizar sua composição, estrutura e método de elaboração. Estes correspondem a seis artefatos de natureza metálica não-ferrosa e um de natureza metálica ferrosa. O objeto metálico ferroso corresponde a uma enxada. As características microestruturais dos objetos estão correlacionadas com a função que esses desempenhavam na época e indicativa de que a enxada possa ter sido feita no Brasil por escravos africanos. A análise da enxada permite concluir que é constituída de um ferro pudlado e que foi processada por fundição e forjamento. Quanto aos objetos não-ferrosos, o rosário é constituído de um latão monofásico mais rico em cobre. Com relação à fabricação do rosário pode-se concluir de que seja de origem européia, sendo decorrente de um minério pirítico. As medalhas são de procedência européia constituídas de latão. Historicamente, pode-se deduzir que são referentes ao século XVIII. Conclui-se que as duas moedas do Sítio Rochedo sejam originárias de fontes diferentes, constatado pelas análises químicas. Porém, as concentrações químicas da moeda de 1821 são próximas a uma das moedas de 40 réis. A presente tese permitiu evidenciar a importância da sistemática de trabalho experimental de caracterização, a partir de técnicas destrutivas e nãodestrutivas de materiais, de objetos arqueológicos para estabelecer seu contexto histórico. / [en] This work undertakes an archeometallurgical study of ferrous and non-ferrous artifacts recovered from historical sites of Rio de Janeiro. The experimental research developed an analytical methodology based on destructive techniques, such as Optical Microscopy (OM), Scanning Electronic Microscopy (SEM) and Transmission Electronic Microscopy (TEM); as well as non- destructive techniques, namely X-Ray Fluorescence (XRF) and Particle Induction X-Ray Emission (PIXE). These artifacts were analyzed in order to characterize their composition, structure and elaboration/processing methods. There are six artifacts with a non-ferrous metallic nature and one with a ferrous metallic nature. The ferrous metallic artifact was a hoe. The microstructure characteristics is related to the usage of this object at that time, and indicates that the hoe could have been made in Brazil by African slaves. The analysis of the hoe indicates that it was elaborated from puddle iron and that it had been processed by foundry and forging. The rosary, one of the non-ferrous artifacts, is formed by singlephase brass riche in copper; and according to historical research it is of European origin, deriving from pyrite ore. The medals are also of European origin and are based on brass. Historically one can deduce that they are dated from the 18th century. The two coins from the Rochedo site most probably came from distinct sources, as validated by the chemical analysis. However, the chemical composition of the 1821 coin is close to that of the 40 réis coin. The present thesis has shown the importance of a systematic methodology to characterize ancient objects combining both destructive and non- destructive techniques.

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[ES] El propósito primordial de esta Tesis Doctoral se fundamenta en poner en valor y difundir el legado de la producción artística y la biografía del pintor alzireño, Teodoro Juan Andreu Sentamans (Alzira, 1870 - Valencia, 1935), con la finalidad de cubrir las lagunas historiográficas existentes hasta la actualidad y aportar datos documentales inéditos de su trayectoria artística. El reconocimiento del artista hasta la fecha ha estado subyugado a haber sido discípulo del gran Joaquín Sorolla y Bastida, sin que se haya contemplado y haber tenido en cuenta su importante actividad artística y docente, sus comisariados en exposiciones, particulares y de otros artistas; su participación asidua en exposiciones nacionales e internacionales, siendo galardonado en varias de ellas; ni el logro de proyectos importantes atribuidos a otras figuras, o simplemente olvidados. Dos circunstancias han confluido para propiciar la inmerecida desatención a la obra de Andreu: ser coetáneo a su maestro, Sorolla, y ser fiel a su estilo costumbrista, negándose a evolucionar hacia una pintura más avanzada. En consecuencia, y fruto del vacío historiográfico, surge la necesidad de realizar este profundo trabajo de investigación, mediante el cual se quiere reivindicar su actividad artística desarrollada entre finales del siglo XIX y principios del XX. Para ello se ha confeccionado un inventario general de gran parte de su producción artística clasificado según la etapa cronológica, y un catálogo razonado de sus obras más relevantes mediante la elaboración de unas fichas técnicas. Debido a la estrecha relación existente entre Sorolla y Andreu se ha llevado a cabo un estudio analítico de una parte representativa de su producción artística, dilucidando, mediante la obtención de resultados y comparativas con la obra seleccionada de Joaquín Sorolla, si el pintor Teodoro Andreu siguió los pasos de su maestro, o utilizó su propia metodología en el uso de la teoría del color y sus pigmentos. Por lo tanto, en este trabajo también se ha elaborado un estudio de los pigmentos utilizados por Andreu en una parte de su obra: análisis realizados por espectrometría de fluorescencia de Rayos X dispersiva en energía (EDXRF), cuyos resultados aportan datos y conclusiones inéditas y determinantes en la obra de Andreu. Uno de los resultados propiciados en esta investigación ha sido que un alto porcentaje de su obra se encuentra localizada en colecciones privadas. En base a esta realidad se ha confeccionado, mediante un programa informático, un museo virtual donde se recoge parte importante de la obra "escondida", a través de una plataforma digital exprofeso, aportando un repertorio de contenidos digitales sustentado con la documentación aportada en este trabajo de investigación, ofreciendo la posibilidad de realizar un recorrido museográfico virtual donde el visitante puede disfrutar de la obra sita en colecciones particulares / [CA] El propòsit primordial d'aquesta Tesi Doctoral es fonamenta a posar en valor i difondre el llegat de la producció artística i la biografia del pintor alzireny, Teodoro Juan Andreu Sentamans (Alzira, 1870 - València, 1935), amb la finalitat de cobrir les llacunes historiogràfiques existents fins a l'actualitat i aportar dades documentals inèdites de la seua trajectòria artística. El reconeixement de l'artista fins hui ha estat subjugat a haver sigut deixeble del gran Joaquín Sorolla i Bastida, sense que s'haja contemplat i haver tingut en compte la seua important activitat artística i docent, els seus comissariats en exposicions, particulars i d'altres artistes; la seua participació assídua en exposicions nacionals i internacionals, sent guardonat en diverses d'elles; ni l'assoliment de projectes importants atribuïts a altres figures, o simplement oblidats. Dues circumstàncies han confluït per a propiciar la immerescuda desatenció a l'obra d'Andreu: ser coetani al seu mestre, Sorolla, i ser fidel al seu estil costumista, negant-se a evolucionar cap a una pintura més avançada. En conseqüència, i fruit del buit historiogràfic, sorgeix la necessitat de realitzar aquest profund treball de recerca, mitjançant el qual es vol reivindicar la seua activitat artística desenvolupada entre finals del segle XIX i principis del XX. Per a això s'ha confeccionat un inventari general de gran part la seua producció artística classificat segons l'etapa cronològica, i un catàleg raonat de les seues obres més rellevants mitjançant l'elaboració d'unes fitxes tècniques. A causa de l'estreta relació existent entre Sorolla i Andreu s'ha dut a terme un estudi analític d'una part representativa de la seua producció artística, dilucidant, mitjançant l'obtenció de resultats i comparatives amb l'obra seleccionada de Joaquín Sorolla, si el pintor Teodoro Andreu va seguir els passos del seu mestre, o va utilitzar la seua pròpia metodologia en l'ús de la teoria del color i els seus pigments. Per tant, en aquest treball també s'ha elaborat un estudi dels pigments utilitzats per Andreu en una part de la seua obra: anàlisis realitzades per espectrometria de fluorescència de Raigs X dispersiva en energia (EDXRF), els resultats dels quals aporten dades i conclusions inèdites i determinants en l'obra d'Andreu. Un dels resultats propiciats en aquesta investigació ha sigut que un alt percentatge de la seua obra es troba localitzada en col·leccions privades. Sobre la base d'aquesta realitat s'ha confeccionat, mitjançant un programa informàtic, un museu virtual on es recull una part important de l'obra "amagada", mitjançant una plataforma digital exprofeso, aportant un repertori de continguts digitals sustentat amb la documentació aportada en aquest treball de recerca, oferint la possibilitat de realitzar un recorregut museogràfic virtual on el visitant pot gaudir de l'obra situada en col·leccions particulars. / [EN] The main purpose of this Doctoral Thesis is based on valuing and expanding the legacy of the artistic production and the biography of the painter from Alzira, Teodoro Juan Andreu Sentamans (Alzira, 1870 - Valencia, 1935) in order to cover the existing historiographical gaps up to the present day and provide unpublished documentary data on his artistic career. Up to the present moment, the recognition of the artist has been subjugated to having been a disciple of the great Joaquín Sorolla y Bastida, without having contemplated and taken into account his important artistic and teaching activity, his curatorships in exhibitions, individuals and other artists; his regular participation in national and international exhibitions, being awarded in several of them; nor the achievement of important projects attributed to other artists, or simply forgotten. Two circumstances have come together to promote undeserved neglect of Andreu's work: being a contemporary of his teacher, Sorolla, and being faithful to his traditional style, refusing to evolve towards a more advanced painting. Consequently, as a result of the historiographical gap, the need of carrying out this deep research arises now. Through it, I want to vindicate Andreu's artistic activity developed between the end of the 19th century and the beginning of the 20th century. For this, a general inventory of all his work has been made, artistic production classified according to the chronological stage, and a reasoned catalog of his most relevant works through the preparation of technical sheets. Due to the close relationship between Sorolla and Andreu, an analytical study of a representative part of his artistic production has been carried out, elucidating, by obtaining results and comparisons with the selected work of Joaquín Sorolla, whether the painter Teodoro Andreu followed the footsteps of his teacher, or used his own methodology in the use of colour theory and its pigments. Therefore, this work has also carried out a study of the pigments used by Andreu in part of his work; analysis carried out by energy dispersive X-ray fluorescence spectometry (EDXRF), whose conclusions in Andreu's work. One of the results fostered in this investigation has been that a high percentage of his work is located in private collections, base don this reality, a virtual museum has been created through a computer programme where all the "hidden" work is collected. Through a digital platform expressly made, it provides a repertoire of digital content supported by the documentation provided in this research work, offering the possibility of taking a virtual museum tour where the visitor can enjoy the work located in private collections. / Ibáñez Bartolomé, M. (2023). Teodoro Andreu Sentamans (1870-1935): Catalogación y estudio analítico de su producción artística [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/195349