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Feasibility Study of a Portable Coupled 3He Detector with LaBr3 Gamma Scintillator for Field Identification and Quantification of Nuclear MaterialStrohmeyer, Daniel C. 2010 May 1900 (has links)
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.
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Fourier transform Raman spectroscopy: Evaluation as a non- destructive technique for studying the degradation of human hair from archaeological and forensic environmentsWilson, Andrew S., Edwards, Howell G.M., Farwell, Dennis W., Janaway, Robert C. January 1999 (has links)
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.
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Doppler-Broadening of Light Nuclei Gamma-Ray SpectraWhitfield, Melinda D. 01 December 2010 (has links)
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.
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Contribution au développement de méthodes d'étalonnage à la spectroscopie Terahertz sur des produits biologiques / Contribution to the development of calibration methods to the Terahertz spectroscopy on biological productsPapillaud, Matthieu 15 December 2011 (has links)
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.
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<strong>IMPLICATIONS OF OFF-NOMINAL CONDITIONS ON LI-ION BATTERY DEGRADATION AND CYCLE LIFE </strong>Maria Terese (16470225) 30 June 2023 (has links)
<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>
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[en] ARCHAEOMETALLURGY STUDY OF METALLIC ARTIFACTS RECOVERED FROM HISTORICALS SITES IN RIO DE JANEIRO / [pt] ESTUDO ARQUEOMETALÚRGICO DE OBJETOS METÁLICOS RESGATADOS DE SÍTIOS HISTÓRICOS DO RIO DE JANEIROGUADALUPE DO NASCIMENTO CAMPOS 03 March 2006 (has links)
[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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Teodoro Andreu Sentamans (1870-1935): Catalogación y estudio analítico de su producción artísticaIbáñez Bartolomé, Mónica 24 July 2023 (has links)
[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
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Non-Destructive Evaluation of Urethane-Ester Coating Systems Using the Scanning Kelvin Probe TechniqueBorth, David J. 31 May 2018 (has links)
No description available.
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