This inquiry explores the possibility of applying principles from Plato?s education system in the Republic to modern military leadership development programs. Both are concerned with producing a ?guard-dog? that will serve the interests of the state rather than exploit vulnerable civilians. Plato proposes educating guardians with a natural disposition to believe the ?noble lie,? that it is better to serve others than to pursue selfinterest for personal gain; but, would the proper tension in moral sensibilities prescribed by the Platonic Grid help or hinder a military leader to successfully act on the battlefield? First, I examine Plato?s theory to familiarize military leaders with the education system from the Republic; including his views on unity, reality, the theory of the forms, and recollection of knowledge that underlie Plato?s enquiry into the nature of justice, and lead to the need for inner harmony of the soul through the proper tension of wisdom, courage, and temperance to rule the three elements of the soul. Then I analyze the key leaders from the Battle of Balaclava, the Battle of Gettysburg, and the siege of the Alamo for possible correlations of the application of the Platonic Grid aligned with the ?noble lie? to success on the battlefield. This includes inquiry into the likelihood that belief in the ?noble lie? can motivate soldiers to make the ultimate sacrifice. I conclude by examining how Plato?s theories could be assimilated into a military pedagogy to produce modern day ?dogs of war? that leads to the startling conclusion that adherence to the ?noble lie? could also be in the self-interest of the guardian who seeks to serve the best interest of her nation.

On Site Inspection is the final measure for verifying compliance of Member States with the Comprehensive Nuclear-Test-Ban Treaty. In order to enable the use of ³⁷Ar as a radiotracer for On Site Inspection, the sources of radioargon background must be characterized and quantified. A radiation transport model of the University of Texas at Austin Nuclear Engineering Teaching Laboratory (NETL) TRIGA reactor was developed to simulate the neutron flux in various regions of the reactor. An activation and depletion code was written to calculate production of ³⁷Ar in the facility based on the results of the radiation transport model. Results showed ³⁷Ar production rates of (6.567±0.31)×10² Bq·kWh⁻¹ in the re- actor pool and the air-filled irradiation facilities, and (5.811±0.40)×10⁴ Bq·kWh⁻¹ in the biological shield. Although ⁴⁰Ca activation in the biological shield was found to dominate the total radioargon inventory, the contribution to the effluent release rate would be diminished by the immobility of Ar generated in the concrete matrix and the long diffusion path of mobile radioargon. Diffusion of radioargon out of the reactor pool was found to limit the release rate but would not significantly affect the integrated release activity. The integrated ³⁷Ar release for an 8 hour operation at 950 kW was calculated to be (1.05±0.8)×10⁷ Bq, with pool emissions continuing for days and biological shield emissions continuing for tens of days following the operation. Sensitivity analyses showed that estimates for the time-dependent concentrations of ³⁷Ar in the NETL TRIGA could be made with the calculated buildup coefficients or through analytical solution of the activation equations for only (n,[gamma]) reactions in stable argon or (n,[alpha]) reactions in ⁴⁰Ca. Analyses also indicated that, for a generalized system, the integrated thermal flux can be used to calculate the buildup due to air activation and the integrated fast flux can be used to calculate the buildup due to calcium activation. Based on the results of the NETL TRIGA, an estimate of the global research reactor source term for ³⁷Ar and an estimate of ground-level ³⁷Ar concentrations near a facility were produced. / text

This study addresses the origin of the combined He-Ne-Ar-Xe noble gas isotopic variation in mantle derived oceanic basalts. High precision heavy noble gas compositions of basalts from the Rochambeau Rift along the Northwestern Lau Basin, the Gakkel Ridge, the Southeast Indian Ridge and the South Atlantic Ridge presented here confirms fundamental differences between the volatile constituents of the depleted mid-ocean ridge basalt (MORB) source and plume sources. We find that the depleted MORB mantle is characterized by systematically lower proportions of Pu-fission derived Xe than the Iceland plume and the Samoan-like plume sampled at the Rochambeau Rift. These two plume sources are associated with low radiogenic \(^{129}Xe/^{130}Xe\) ratios that are not attributable to recycled atmosphere and must sample ancient (4.45 Ga) volatile rich mantle reservoir that experienced a lower degree of mantle processing than the depleted MORB source. I report \(^{128}Xe/^{130}Xe\) ratios in excess with respect to the atmosphere in deeply erupting Gakkel lavas, similar to mantle derived volatiles in natural gas samples. Deconvolution of fission derived xenon isotopes indicate that natural gas samples and the Gakkel MORBs are derived from the same volatile depleted mantle reservoir. The radiogenic He isotopic composition, the low estimated ratio of Pu to U derived xenon isotopes, and the low \(^{129}Xe/^{130}Xe_E\) ratio found in the source of the West Volcanic Zone (WVZ) along the Gakkel Ridge indicates the presence of increased amounts of recycled atmospheric volatiles. I suggest that the low \(^{129}Xe/^{130}Xe\) ratio beneath the WVZ cannot be explained by sampling an ancient (>4.45 Ga) lithospheric mantle component that evolved in isolation from convection throughout Earth's history. Instead, the Xe isotopic composition may be consistent with the presence of subduction derived metasomatizing fluids with atmospheric heavy noble gases trapped in the sub-continental lithospheric mantle sampled along the ridge. Available Ne isotope MORB data and new high precision Ne data presented in this study (including basalts from the East Pacific Rise, the Galapagos Spreading Center, and the Juan de Fuca Ridge) allows me to construct a combined He-Ne isotope distribution and infer first order source mixing systematics in the upper mantle. / Earth and Planetary Sciences

Femtosecond time scale allows us to follow and control atomic and molecular motion. The atomic vibrations happen in the range of femtosecond scale. Thus, femtosecond technology effectively measures the atomic vibration. However, to determine electron motion, one needs to reach sub-femtosecond time scale that is in attosecond time scale. High Harmonic Generation (HHG) is a non-linear process that converts infrared light to shortest wavelength, such as in the XUV regime. HHG allows to explore electronic motion and to control electron dynamics. HHG easily reaches to XUV region and is enabling attosecond pulse generation. In this thesis we focused to generate attosecond pulses by using noble gases and their mixtures. We used only argon gas, only hydrogen molecule and their mixture with neon gas. We wanted to improve the conversion efficiency (10^-6) of the fundamental light into high harmonics. We use Ne and H2 gas mixture to look enhancement of the HHs.

This research emphasizes on the use of seeded growth in synthesis of noble metal nanocrystals with precise control over the size, shape, and composition. In the first part of this work, I have produced Au nanocrystals with single-crystal structure and truly spherical profiles and investigated their optical properties and self-assembly as induced by dilution with water. These Au nanospheres were generated in high yield and purity, together with controllable sizes continually increased from 5 to 150 nm. I also found these Au nanospheres self-assembled into dimers, larger aggregates, and wavy nanowires, respectively, as diluted with water. In the second part of this work, I demonstrate the kinetic control can be implemented to control the shape of mono- and bi-metallic nanocrystals in seeded growth. The as-prepared single-crystal nanospheres of Au were employed as seeds to synthesize of tetrahedral Au nanocrystals and Au@Pd core-shell nanocrystals with six distinct shapes. The success of the two demonstrations relies on manipulation of reaction kinetics to achieve different product shapes. The reaction kinetics was controlled by varying a set of reaction parameters, including the type and concentration of capping agent, the amount of reductant, and the injection rate of metal precursor solution. In the final part of this work, I will discuss an unusual change in crystallinity observed in seeded growth of Au nanocrystals on Au seeds. In particular, single-crystal Au seeds treated with a chemical species could develop twin defects during the seed-mediated growth process to yield multiply twinned products.

Author's Thesis (doctoral)--Université Bordeaux III, 2003. / Includes bibliographical references (p. [382]-413) and index.

Les études de mélanges binaires sous conditions extrêmes ont mené à la découverte de solides appelés composés van der Waals. La découverte d’un composé van der Waals dans un mélange de deux gaz nobles par Loubeyre et al. (1993) permet de supposer que différentes combinaisons de gaz nobles formeront, aux conditions pression-température-concentration appropriées, de tels solides. Des échantillons de gaz nobles (néon + argon) et (hélium + argon) furent étudiés sous hautes pressions par diffraction de rayons X issus du rayonnement synchrotron dans le but de former et caractériser un composé inédit. Une faible miscibilité des espèces étudiées est observée via la présence de démixtions et de solutions solides dans les échantillons. Parallèlement, une étude du composé binaire (azote + méthane) a été poursuivie par l’affinement des positions moléculaires d’un composé van der Waals connu pour ce système. Des solutions potentielles pour la structure cristalline sont proposées et discutées.

We have built an imaging mass spectrometer adapted for ultrashort laser pulses as its ionization technique, as an alternative to other imaging techniques. Before my arrival, the mass spectrometer has only been subject to preliminary tests on noble gases. Since then, we’ve made some modifications to the system in order to properly analyze solids. This thesis shows how we obtain our ultrashort laser pulses, the inner workings of our homemade imaging mass spectrometer, and the results that we’ve obtained with it so far. We tested two modes of operation concerning the extraction of the ions from the system into the mass analyzer: continuous and pulsed. We discuss the advantages and disadvantages of each configuration. We also display preliminary imaging results with our imaging technique of a simple WO3 and ITO structure. We conclude by comparing the resolution of this image to the different techniques in imaging mass spectrometry, how we can further improve our mass spectrometer, and the future use of this machine. Nous avons construit un spectromètre de masse adapté pour les pulses de laser très courts comme technique d’ionisation, pour acquisition des images d’un échantillon. Avant je suis arrivé, le spectromètre de masse avait seulement été utilisé pour des tests préliminaires de gaz nobles. Depuis ce moment, nous avons modifié le système pour analyser les solides. Cette thèse démontre comment on obtient nos pulses de laser très courts, comment notre spectromètre fait maison fonctionne et les résultats nous avons obtenus jusqu’à présent. Nous avons testé deux configurations différentes au sujet de l’extraction des ions du système : constant et pulsé. Nous discutons aussi les avantages et désavantages de chaque mode d’opération. Nous démontrons aussi des images préliminaires d’un substrat mixte de WO3 et ITO. Nous concluons par comparer la résolution des images aux autres techniques de collection d’images, comment nous pouvons améliorer notre spectromètre de masse et les plans pour la machine dans le futur.

Orientador: Yoshitaka Gushikem / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-27T17:04:12Z (GMT). No. of bitstreams: 1 Fattori_Natalia_D.pdf: 3454511 bytes, checksum: 8b2aa591a45da1692fb09a098dea4e58 (MD5) Previous issue date: 2014 / Resumo: O presente trabalho descreve um método de preparação de nanopartículas metálicas suportadas em sílicas mesoporosas organofuncionalizadas. Dois diferentes substratos foram explorados: uma sílica mesoporosa constituída de uma estrutura porosa altamente ordenada e uniforme, composta de poros ou canais cilíndricos dispostos paralelamente e empacotados em arranjo hexagonal (SBA-15), e uma sílica mesoporosa caracterizada por uma rede desordenada de poros, de tamanho e forma variados, distribuídos e interconectados aleatoriamente ao longo da estrutura porosa (SMD). As duas matrizes tiveram suas superfícies quimicamente modificadas com dois diferentes agentes funcionalizantes constituídos de cátions orgânicos (R+Cl-) com propriedades de troca-iônica, derivados das moléculas 1-metilimidazol (Imi) e 4,4?-bipiridina (Bipy). Em ambos os casos, as propriedades íontrocadoras dos cátions orgânicos ancorados na superfície das sílicas permitem a retenção de ânions complexos de metais nobres ([AuCl4]-, [PtCl6]2- e [PdCl4]2-) confinados na estrutura porosa. Estas espécies foram convertidas in situ nas nanopartículas metálicas de interesse pela redução dos íons metálicos com agentes redutores adequados. As matrizes modificadas com o grupo funcional Imi foram utilizadas como suportes para a preparação e estabilização de nanopartículas metálicas (Au, Pt, Pd e ligas metálicas Au-Pt, Au-Pd e Pt-Pd). Já as matrizes modificadas com o grupo funcional Bipy foram utilizadas como suportes para o preparo de nanopartículas de ouro / Abstract: The present work describes a new method for preparing metal nanoparticles supported on organofuncionalized mesoporous silica. Two different substrates were used: a mesoporous silica constituted by a highly ordered and uniform porous framework, with parallel cylindrical pore channels packed in a hexagonal array (SBA-15), and a mesoporous silica characterized by a disordered porous framework, with non-uniform size and shape, distributed and interconnected randomly throughout the porous structure (SMD). Both substrates were chemically modified with two different functional groups constituted of organic cations (R+Cl-) with ion-exchange properties, derivative from the molecules 1-methylimidazole (Imi) and 4,4?-bipyridine (Bipy). In both cases, the ion-exchange properties of the cationic groups attached to the silica surface allows the retention of anionic noble metal complex ([AuCl4]-, [PtCl6]2- e [PdCl4]2-), confined within the porous structure. These species were converted in situ into metal nanoparticles by means of reduction of the metal ions with proper reducing agents. The substrates modified with the functional group Imi were used as supports for the preparation and stabilization of noble metal nanoparticles (Au, Pt, Pd and metal alloys Au-Pt, Au-Pd and Pd-Pt). The substrates modified with the functional group Bipy were used as supported for the preparation of gold nanoparticles / Doutorado / Quimica Inorganica / Doutor em Ciências

A strategy based on reticulating metal ions and organic ligands into atomically precise gold and silver nanoclusters (NCs) with high monodispersity has been advanced to a point that allows the design of NCs with strict stoichiometries, functionalities and valence. Of the Ag NCs discovered, Ag44 is the most studied, not only due to its high absorption that transcends the visible spectrum suitable for photovoltaics but also because of its long excited state lifetime, as revealed by nanosecond transient absorption spectroscopy. A major principle discovered in this dissertation is the ability to produce Ag44 in scalable amounts and with high stability in addition to modulation of the functional groups of the organic ligands via a fast and complete ligand exchange process. This new discovery has led to the development of synthetic designs in which new sizes were obtained by varying the reaction parameters (e.g., ligands functionality, reaction temperature and time), namely, Ag29 using dithiols and phosphines. The synthesized NCs possess tetravalent functionalities that facilitate their crystallization and characterization. Furthermore, Ag29 glows red and is therefore a possible candidate for sensing and imaging applications.