The development of a disintegrating core-body for use in an art bronze foundry, which employs the ceramic shell investment process, begins with an investigation of four principal materials that will constitute the core formula. The specifications for the disintegration of the designed core-body formula fall within the parameters that are normally set and used in the ceramic shell art bronze casting process. The raison d’ être for the disintegrating formula is based on the premise that cement breaks down (spalling) after being subjected to heat above a certain temperature. It was shown that pure cement in the form of naked test bars 100 mm x 20 mm x 20 mm does indeed break down into separate pieces when fired to and above 9000C; where 9000C is the lowest recommended temperature required for sintering the ceramic shell investment mould. The addition of calcium carbonate to pure cement in the form of naked test bars, produced a more unified formula that did not break into separate pieces when fired to 9450C. However this combination of cement and calcium carbonate had a slow setting time of 12 hours and a shrinkage value of 2,3%, which were both above the parameters being sought for a quick-setting formula with a shrinkage value of below 1%. The combination of cement, plaster of paris and silica produced formulae that set within six hours and had shrinkage values of less than 1% but did not disintegrate within 72 hours. It was only after the addition of calcium carbonate to the these mixes that formulae resulted that set within six hours, had relatively low shrinkage values and showed signs of breaking up after 60 hours. It was further shown that by altering the ratios of cement, plaster of paris, calcium carbonate and silica, that the parameters for quick-setting formulae with shrinkage values of 1% and below, that also disintegrated within 55 hours, could be achieved. xvi It was also proved by subjecting these formulae to higher relative humidity conditions that the disintegrating times could be reduced and brought to below 48 hours. Selected formulae were then subjected to temperatures of between 9000C and 10000C. It was found that as the temperatures were increased so the disintegration times were reduced and were even further reduced under higher relative humidity conditions. It was found from the above experiments that the selected formula determined to be suitable in all respects as a disintegrating core-body was too difficult to remove from the hollow bronze cast when subjected to an actual bronze pour. Further experimentation using increased proportions of silica in the formula resulted in a final core-body that could be quickly and easily removed from its bronze cast as soon as the core-body had cooled to room temperature. The selected core-body formula (F21D) that was used in the final set of bronze casting procedures was found to function optimally when fired to a temperature of 9000C and could be quickly and easily removed from the bronze casts leaving a clean inner bronze surface, free from any remnants of the fired core. The document concludes by recording the delimitations and advantages of the final core-body formula F21D, as well as making recommendations based on these parameters for further study relating to disintegrating core-body formulations.

Spectroscopic measurements of the helium atom are performed to high precision using an atomic beam apparatus and electro-optic laser techniques. These measurements, in addition to serving as a test of helium theory, also provide a new determination of the fine structure constant α. An apparatus was designed and built to overcome limitations encountered in a previous experiment. Not only did this allow an improved level of precision but also enabled new consistency checks, including an extremely useful measurement in 3He. I discuss the details of the experimental setup along with the major changes and improvements. A new value for the J = 0 to 2 fine structure interval in the 23P state of 4He is measured to be 31 908 131.25(30) kHz. The 300 Hz precision of this result represents an improvement over previous results by more than a factor of three. Combined with the latest theoretical calculations, this yields a new determination of α with better than 5 ppb uncertainty, α-1 = 137.035 999 55(64).

No description available.

Digital image processing is one of the potential technologies used in precision agriculture to gather information, such as seed emergence, plant health, and phenology from the digital images. Despite its potential, the rate of adoption is slow due to limited accessibility, unsuitability to specific issues, unaffordability, and high technical knowledge requirement from the clientele. Therefore, the development of open source image processing applications that are task-specific, easy-to-use, requiring fewer inputs, and rich with features will be beneficial to the users/farmers for adoption. The Fiji software, an open source free image processing ImageJ platform, was used in this application development study. A collection of four different agricultural field applications were selected to address the existing issues and develop image processing tools by applying novel approaches and simple mathematical principles. First, an automated application, using a digital image and “pixel-march” method, performed multiple radial measurements of sunflower floral components. At least 32 measurements for ray florets and eight for the disc were required statistically for accurate dimensions. Second, the color calibration of digital images addressed the light intensity variations of images using standard calibration chart and derived color calibration matrix from selected color patches. Calibration using just three-color patches: red, green, and blue was sufficient to obtain images of uniform intensity. Third, plant stand count and their spatial distribution from UAS images were determined with an accuracy of ≈96 %, through pixel-profile identification method and plant cluster segmentation. Fourth, the soybean phenological stages from the PhenoCam time-lapse imagery were analyzed and they matched with the manual visual observation. The green leaf index produced the minimum variations from its smoothed curve. The time of image capture and PhenoCam distances had significant effects on the vegetation indices analyzed. A simplified approach using kymograph was developed, which was quick and efficient for phenological observations. Based on the study, these tools can be equally applied to other scenarios, or new user-coded, user-friendly, image processing tools can be developed to address specific requirements. In conclusion, these successful results demonstrated the suitability and possibility of task-specific, open source, digital image processing tools development for agricultural field applications. / United States. Agricultural Research Service / National Institute of Food and Agriculture (U.S.)

Two studies of reconstruction processes in the Northern Great Plains (NGP) are presented. The first study is a retrospective study on United States Fish and Wildlife Service (USFWS) managed lands seeded with a high diversity (>15 species) seed mix. Sites were grouped by available management history to find management tactics which may trend sites towards a more successful state. A large amount of variation was captured. Results showed uncontrollable factors may be driving the outcomes of these reconstructions. Attention should be paid to uncontrolled and landscape factors to drive management of each site. A second study investigates a possible method to establish specialized seed mixes. Precision Prairie Restoration (PPR) was used to establish five repetitions of six treatments. Early results are optimistic with several target species becoming established. Future sampling will be needed to determine success of this method.

The content of this work is an overview of precision approach used by GNSS and avionics for operation in low visibility conditions. This thesis describes existing requirements and proposals for new standards that are important to define GBAS performance. The objective of this work is to compare the alternative systems to guide aircraft during precision approach CAT II/III. GBAS operational implementation is additionally devised in this thesis.

La précision dans la mesure du temps est considérée par l’historiographie comme un élément qui a émergé simultanément avec la géométrisation des phénomènes naturels. Les savants du XVIIe siècle sont ainsi étudiés dans ce cadre comme des Philosophes Naturels qui considèrent comme seul argument fiable les résultats quantitatifs de mesure et de précision. Dans cette thèse nous avons étudié cette émergence, dans le cadre emblématique de la théorie gravitationnelle de Newton. Dans un premier temps nous avons défini la précision du temps comme un élément qui demande une amélioration constante par le biais des instruments. Nous avons ensuite découpé la connaissance scientifique en trois parties distinctes : la construction de la théorie, son application et la confirmation de cette dernière. Nous avons étudié la précision dans la mesure du temps et son rôle en tant qu’élément de validation dans les trois parties en mettant l’accent sur la première. Dans ce cadre d’étude nous avons démontré que la thèse couramment répandue dans l’historiographie jusqu’ici est problématique. La précision dans la mesure du temps n’a pas de relation de causalité directe avec la géométrisation de la nature. Son importance au sein des théories, au cas par cas, est évolutive et s’est pendant longtemps retrouvée cantonnée dans les aspects techniques du savoir avant de trouver en retour une place importante dans la théorie. L’étude des aspects techniques nous ont amené à l’exploration de documents liés à la détermination des longitudes en mer, et sa relation intrinsèque au développement du commerce entre continents. Dans ce cadre nous avons détaillé des aspects jusque là obscurs du « mesureur de temps » de Galilée, proposé par ce dernier comme un instrument de grande précision qui participe à la solution des longitudes. / Precision in time measurement is considered by historiography as an element that emerged simultaneously with the geometrization of natural phenomena. The scholars of the seventeenth century are therefore studied in this context as Natural Philosophers who consider as the only reliable argument the quantitative results of measurement and precision. In this thesis we have studied this emergence, in the emblematic framework of Newton's gravitational theory. At first we defined the accuracy of time as an element that requires constant improvement through the instruments. We then divided the scientific knowledge into three distinct parts: the construction of the theory, its application and the confirmation of the theory. We studied the accuracy (here as synonym of precision) in the measurement of time and its role as a validation element in all three parts with a focus on the former. In this framework of study we have shown that the thesis commonly used in historiography so far is problematic. Precision in the measurement of time has no direct causal relation with the geometrization of nature. Its importance in theories, on a case-by-case study, is evolutionary and has for a long time been confined to the technical aspects of knowledge before finding an important place in the theory. The study of technical aspects led us to explore documents related to the determination of longitudes at sea, and its intrinsic relationship to the development of trade between continents. In this context we have detailed previously unclear aspects of Galileo's "time measurer", proposed by the later as an instrument of great accuracy being part of the longitude solution.

No description available.

Agriculture faces many challenges related to the increasing food demands of a growing global population and the sustainable use of resources in a changing environment. To address them, we need reliable information sources, like exploiting hyperspectral satellite, airborne, and ground-based remote sensing data to observe phenological traits through a crops growth cycle and gather information to precisely diagnose when, why, and where a crop is suffering negative impacts. By combining hyperspectral capabilities with unmanned aerial vehicles (UAVs), there is an increased capacity for providing time-critical monitoring and new insights into patterns of crop development. However, considerable effort is required to effectively utilize UAV-integrated hyperspectral systems in crop-modeling and crop-breeding tasks. Here, a UAV-based hyperspectral solution for mapping crop physiological parameters was explored within a machine learning framework. To do this, a range of complementary measurements were collected from a field-based phenotyping experiment, based on a diversity panel of wild tomato (Solanum pimpinellifolium) that were grown under fresh and saline conditions. From the UAV data, positionally accurate reflectance retrievals were produced using a computationally robust automated georectification and mosaicking methodology. The resulting multitemporal UAV data were then employed to retrieve leaf-chlorophyll (Chl) dynamics via a machine learning framework. Several approaches were evaluated to identify the best-performing regression supervised methods. An investigation of two learning strategies (i.e., sequential and retraining) and the value of using spectral bands and vegetation indices (VIs) as prediction features was also performed. Finally, the utility of UAVbased hyperspectral phenotyping was demonstrated by detecting the effects of salt-stress on the different tomato accessions by estimating the salt-induced senescence index from the retrieved Chl dynamics, facilitating the identification of salt-tolerant candidates for future investigations. This research illustrates the potential of UAV-based hyperspectral imaging for plant phenotyping and precision agriculture. In particular, a) developing systematic imaging calibration and pre-processing workflows; b) exploring machine learning-driven tools for retrieving plant phenological dynamics; c) establishing a plant stress detection approach from hyperspectral-derived metrics; and d) providing new insights into using computer vision, big-data analytics, and modeling strategies to deal effectively with the complexity of the UAV-based hyperspectral data in mapping plant physiological indicators.

In this dissertation, we aimed to bring together a team of clinical experts, translational researchers, biostaticians and bioinformaticians to develop and implement innovative scientific methodologies in precision medicine applied to High Grade Serous Ovarian Cancer (HGS OvCa). We used a variety of translational and computational methods in order to generate impactful outcomes. These pipelines produced statistically robust results, with particular emphasis on drawing clinical and biological correlations. The results presented here contribute to the body of evidence necessary to substantiate these findings in a clinical setting. Bioassays, PDX models and ancillary specimen evaluation of previous clinical trials will help to validate our candidate biomarkers. Enhanced understanding of the molecular pathology of disease grounded in acquisition of genomic knowledge will facilitate the development of targeted treatment in cancer. Because clinical trials must be developed with correct metrics, patient selection and drug efficacy should incorporate adaptive designs. / Doctorat en Sciences médicales (Santé Publique) / info:eu-repo/semantics/nonPublished