The aim of this work was to improve the heat capacity estimation of a material for usage within a CALPHAD-type assessment. An algorithm is derived that estimates the trend of heat capacity with temperature based on zero Kelvin properties and the thermal expansion coefficient at the Debye temperature. The algorithm predicts not only the trend of heat capacity but also the temperature trend of the volume and the bulk modulus, which can be also included in new thermodynamic databases. The algorithm is used to assess thermophysical properties of the intermetallic phases eta (Fe2Al5), epsilon~(Fe5Al8) and tau4 (FeAl3Si2). The heat capacity of the intermetallic phases zeta, eta, theta and epsilon of the Al-Fe system and of tau4 of the Al-Fe-Si system was measured using DSC. For the phases zeta, eta, and theta, a non-linearly increasing heat capacity approaching the melting temperature was observed. In addition, the heat capacity of three bcc-based Al-Fe samples including the B2-->A2 transition were determined. The Al-rich section of the Al-Fe phase diagram was studied using DTA and quenching experiments. The homogeneity ranges of the intermetallic phases were determined using SEM/WDS measurements. Based on own and literature values, a thermodynamic description of the Al-Fe system was assessed including the modelling of A2/B2 ordering and the homogeneity range of all intermetallic phases. In addition, thermodynamic parameters of the Al-Fe-Si, Al-Fe-Mg, and the Fe-Mg-Si system were assessed to obtain a thermodynamic description of the Al-rich side of the Al-Fe-Si-Mg system, which can be used to study phase transitions of typical A356-aluminium alloys.

NiSi and Ni(Pt)Si, and of the effects of dissociated ammonia on oxide reduction was carried out under controlled ultrahigh vacuum (UHV) conditions. X-ray photoelectron spectroscopy (XPS) has been used to characterize the evolution of surface composition. Vicinal surfaces on NiSi and Ni(Pt)Si were formed in UHV by a combination of Ar+ sputtering and thermal annealing. Oxidation of these surfaces in the presence of either O+O2 or pure O2 at room temperature results in the initial formation of a SiO2 layer ~ 7 Å thick. Subsequent exposure to O2 yields no further oxidation. Continued exposure to O+O2, however, results in rapid silicon consumption and, at higher exposures, the kinetically-driven oxidation of the transition metal(s), with oxides >35Ǻ thick formed on all samples, without passivation. The addition of Pt retards but does not eliminate oxide growth or Ni oxidation. At higher exposures, in Ni(Pt)Si surface the kinetically-limited oxidation of Pt results in Pt silicate formation. Substrate dopant type has almost no effect on oxidation rate. Reduction of the silicon oxide/metal silicate is carried out by reacting with dissociated NH3 at room temperature. The reduction from dissociated ammonia (NHx+H) on silicon oxide/ metal silicate layer shows selective reduction of the metal oxide/silicate layer, but does not react with SiO2 at ambient temperature.

Different type of images provided by various combinations of cameras have the power to help increase and optimize plant growth. Along with a powerful deep learning model, for the purpose of detecting these stress indicators in RGB images, can significantly increase the harvest yield. The field of AI solutions in agriculture is not vastly explored and this thesis aims to take a first step in helping explore different techniques to detect early plant stress. Within this work, different types and combinations of camera modules will initially be reviewed and evaluated based on the amount of information they provide. Using the chosen cameras, we manually set up datasets and annotations, chose and then trained a suitable and appropriate algorithm to predict deviations from an ideal state in plant production. The algorithm chosen was Faster RCNN, which resulted in having a very high detection accuracy. Along with the main type of cameras, a new particular type of images analysis, named SI-NDVI, is done using a particular combination of the main three cameras and the results show that it is able to detect vegetation and able to predict or show if a plant is stressed or not. An in-depth research is done on all these techniques to create a good quality dataset for the purpose of early stress detection. / Olika typer av bilder försedda av olika kombinationer av kameror har kapaciteten att hjälpa öka och optimera odling av växter. Tillsammans med en kraftfull deep learning-modell, för att detektera olika stressindikatorer i RGB bilder, kan signifikant öka skördar. Fältet av AI-lösningar inom jordbruk är inte väl utforskat och denna uppsats siktar på att ta ett första steg i utforskandet av olika tekniker för att detektera tidig stress hos växter. Inom detta arbete kommer olika typer och kombinationer av kameramoduler bli utvärderade baserat på hur mycket information de kan förse. Genom att använda de valda kamerorna skapar vi själva dataseten och kategoriserar dem, därefter välja och träna en lämplig algoritm för att förutspå förändringar från ett idealt tillstånd för växtens tillväxt. Algoritmen som valdes var Faster RCNN, vilken hade en väldigt hög träffsäkerhet. Parallellt med de huvudsakliga kamerorna genomförs en ny typ av bildanalys vid namn SI-NDVI genom användandet av en särskild kombination av de tre kameror och resultat visar att det är möjligt att detektera vegetation och förutspå eller visa om en växt är stressad eller inte. En fördjupad undersökning genomförs på alla dessa tekniker för att skapa ett dataset av god kvalité för att kunna förutspå tidig stress.

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Los materiales compuestos de matriz cerámica basados en carburo de silicio (SiC) presentan excelentes propiedades mecánicas y gran estabilidad estructural a temperaturas superiores a los 1000°C. Por otro lado, el iridio presenta excelentes propiedades a bajas y altas temperaturas y tiene la ventaja de ser altamente resistente a la corrosión. El principal objetivo de esta Tesis Doctoral es sintetizar materiales compuestos basados en SiC e Ir mediante infiltración reactiva con el fin de lograr una sinergia entre las propiedades individuales de los materiales constituyentes. Para lograr una comprensión total del método de procesamiento por infiltración reactiva en estos materiales, la Tesis fue organizada en 7 capítulos. En el capítulo 1 se desarrolla el estado del arte de los materiales compuestos. En el capítulo 2 se explican los materiales y métodos empleados en el seguimiento de la reacción de infiltración, las técnicas de caracterización y los ensayos termomecánicos. En el capítulo 3 se realiza un estudio fundamental de la mojadura de aleaciones de Si-Ir con creciente concentración de Ir sobre sustratos de carbono y SiC. En el capítulo 4 se estudia la reacción del estado sólido y los fenómenos de interfase del Ir puro sobre sustratos de SiC. En el capítulo 5 se evalúa el efecto de la atmósfera de procesamiento en los materiales compuestos finales. En el capítulo 6 se sintetizan los materiales compuestos SiC/Si-IrSi3, donde se estudia el método de infiltración reactiva gracias a la técnica de gota yacente y se evalúan las propiedades finales del material producido. Finalmente, en el capítulo 7 se resumen las principales conclusiones generadas en la memoria. En general, este estudio es una contribución importante para el desarrollo de materiales avanzados que puedan ser utilizados en ambientes altamente oxidantes y/o que requieran alta resistencia a la corrosión (como, por ejemplo, aplicaciones electrónicas). En conclusión, en esta Tesis Doctoral, se ofrece un estudio sistemático y fundamental de la infiltración reactiva para la síntesis de materiales compuestos basados en SiC e Ir. Queda demostrado que los materiales compuestos SiC/Si-IrSi3 surgen como candidatos ideales para aplicaciones estructurales de alta temperatura debido a sus excelentes propiedades termomecánicas y su prometedora resistencia a la oxidación.

Thesis advisor: Boyd Taylor Coolman / This dissertation offers a new systematic interpretation and retrieval of the theology and spirituality of the 12th century master Hugh of St. Victor, an interpretation centered on the Triune LORD’s unifying and reforming work in history in the three days of Jesus Christ’s dying, burial, and rising. Seen from the vantage of Hugh’s treatise On the Three Days, these ‘three days’ of Jesus Christ’s ‘Passover’ are, for Hugh, the plenary revelation of the Trinity in history – and so an eschatological disclosure – and are at once the soteriological and spiritual center of his theology. The work of the dissertation is, in part one, to explore the objective polarity of the LORD’s work in the three days. This entails an in-depth treatment of Hugh’s christology, including the currently contested and historically misconstrued territory of Hugh’s doctrine of the hypostatic union. Moreover, the project brings out the integral connections between Hugh’s doctrine of the hypostatic union and his soteriology of the re-formation of all of history in the three days. This triadic soteriological scheme in turn correlates to three degrees of theological language and of Triune self-revelation in history. The task of part two of the dissertation is to study the subjective polarity of Spirit-enabled human participation in Christ’s dying, burial, and rising. Hugh’s spirituality and practice of theology are explored as means of human re-formation unto wonder, wisdom, and charity – in short, unto mystical and ultimately eschatological union with God – through participation in the paschal mystery. These chapters thus systematize and explore aspects of Hugh’s thought as diverse as the communal formation at the Abbey of St. Victor, humility, study of the liberal arts and memorization of Scripture, theological meditation, allegorical and tropological biblical interpretation, works of charity, and the responsive eros of Hugh’s contemplative mysticism, all as means of sharing, by turns, in Christ’s dying, burial, and rising. The third and final part of the dissertation attempts a contemporary practice of Hugonian theology. It places the Hugonian theology retrieved in parts one and two in the context of the reception of Laudato Si’ in order to offer a christological and mystical companion to Pope Francis’ encyclical. It argues that the ‘ecological conversion’ for which Pope Francis calls, as a subjective participation in Christ, implicitly depends upon a robust enough objective christology to make the summons to particularly ‘ecological’ conversion coherent and compelling. Hence the contemporary eco-christologies of Sallie McFague and Celia Deane-Drummond are studied and adjudicated. Finally, on the basis of the gains accrued in the course of those eco-christological engagements, a renewed Hugonian christology and soteriology is proposed as a framework for and aid to the spiritual and moral implementation of Laudato Si’. Ecological conversion is itself, most properly, a process of human re-formation in the three days of Jesus Christ’s Passover, and hence practical efforts to teach and implement Laudato Si’ benefit from a Hugonian theological and spiritual approach. / Thesis (PhD) — Boston College, 2018. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Theology.

Chemical and topographic surface patterning for the preparation of functional surfaces and particle arrays has been intensively investigated and widely applied in sensor technology, engineering of adhesion and wetting, catalysis, as well as nanobioanalytics. However, the parallel high-throughput functionalization of surfaces with microparticle arrays under ambient conditions by state-of-the-art surface patterning methods has remained challenging. The aim of this thesis is the parallel generation of microparticle arrays on surfaces to tailor the surface properties. Two strategies are studied for this purpose. The first strategy, inspired by the functional principles of adhesive secretion of insect feet’s hairy contact elements yielding tiny droplets as footprints onto contact substrates, involves the formation of microdot arrays by capillary submicron stamping using spongy continuous nanoporous block copolymer stamps with regular hexagonal arrays of contact elements. After infiltration of AgNO3 solution from the stamps’ backside, arrays of discrete two-dimensional AgNO3 microdots with an average diameter ~ 730 nm on silicon wafers extending several square millimetres were generated, while under higher pressure holey AgNO3 films were obtained. Subsequently, the patterns were transferred into Si wafers by surface-limited metal-assisted chemical etching (MACE). Topographically patterned silicon (tpSi) characterized by hexagonal arrays of wells resulted from MACE of Si wafers patterned with AgNO3 microdots, while MACE of Si wafers patterned with holey AgNO3 films yielded ordered Si pillar arrays. H2PtCl6, PdCl2 and HAuCl4 aqueous solutions were also employed as inks for preparation of tpSi by insect-inspired capillary sub-microstamping and MACE. Exploratory experiments suggest that inkjet printing of polymeric inks onto tpSi could yield persistent and scratch-resistant polymer blot patterns without coffee ring-like features for potential utilization as permanent identity labels or quick response codes. Hexagonal arrays of Au microparticles were rationally positioned by solid-state dewetting of thin gold films on tpSi at an elevated temperature under Ar atmosphere. The rationally positioned Au microparticles subsequently acted as seeds for the growth of dense, homogeneous layers of overlapping three-dimensional (3D) gold nanodendrites by templated galvanic displacement reactions. The obtained 3D gold nanodendrite layers on tpSi featuring high specific surfaces as well as abundance of sharp edges and vertices showed promising performances in SERS-based sensing and the heterocatalytic reduction of 4-nitrophenol to 4-aminophenol. The second example involves the functionalization of polymer surfaces with arrays of inorganic lubricant microparticles for friction management and the tailoring of tribological properties based on an imprint lithographic approach. For example, the tailoring of the interfacial shear behavior of a movable polymer part might be customized in this way by functionalizing the polymeric parts’ surfaces with MoS2 microparticle arrays. Monodomain monolayers of MoS2 microparticles were prepared on SiO2-coated Si wafers via thermal sulfurization arrays of ammonium tetrathiomolybdate microparticles obtained by imprint lithography. After transfer of the MoS2 microparticle arrays to poly(methyl methacrylate) (PMMA) monoliths (PMMA_MoS2) under conservation of the array order in such a way that the MoS2 microparticles were partially embedded into the PMMA and partially exposed, the obtained PMMA_MoS2 exhibited modified mechanical properties characterized by low friction coefficients half as that of non-modified PMMA monoliths. Therefore, the functionalization of surfaces with microparticle arrays is a viable and promising strategy to generate unprecedented surface functionalities.

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This paper presents a modulator driver realized as a breakdown voltage doubler which can provide a high output swing of 7.6 Vpp,diff for load impedances as low as 30 Ω, thus overcoming the limitation imposed by the collector-emitter breakdown voltage. The open-collector design gives an important degree of freedom regarding the modulator load to be driven, while significantly reducing the circuit's power consumption. The driver is capable of running at 30 Gb/s while dissipating 1 W of DC power. Thanks to the inductorless design, the active area occupied by the circuit is only 0.28 mm × 0.23 mm. The driver was realized in a 250 nm SiGe BiCMOS technology.