Blasting is a critical part of most mining operations. The primary function of blasting is to fragment and move rock. For decades, attempts have been made at increasing the efficiency of blasting to reduce costs and increase production. Most of these attempts involve trial and error techniques that focus on changing a single output. These techniques are costly and time consuming and it has been shown that as one output is optimized other outputs move away from their optimum level. To truly optimize a blasting program, the transfer of explosive energy into individual components must be quantified. Explosive energy is broken down into five primary components: rock fragmentation, heave, ground vibration, air blast, and heat. Fragmentation and heave are considered beneficial components while the remaining are considered waste. Past energy partitioning research has been able to account for less than 30% of a blast’s total explosive energy. The purpose of this dissertation was to account for a greater percentage of the explosive energy available during a blast. These values were determined using measurement techniques not previously applied to energy partitioning research. Four small-scale test series were completed, each designed to isolate individual energy components. Specific energy components measured include borehole chambering, elastic deformation (ground vibration), translational and rotational kinetic energy (heave), and air overpressure (air blast). This research was able to account for 73% of the total explosive energy. Borehole chambering (13%), rotational kinetic energy (25%), translational kinetic energy (5%), and air overpressure (28%) were determined to be the largest components. Prior research efforts have largely ignored rotational kinetic energy and have only been able to offer predictions for the values of borehole chambering and air overpressure energies. This dissertation accounted for a significantly higher percentage of total available explosive energy than previous research efforts using novel measurement techniques. It was shown that borehole chambering, heave, and air blast are the largest energy components in a blast. In addition to quantifying specific energy partitions, a basic goal programming objective function was proposed, incorporating explosive energy partitioning and blasting parameters into a framework that can be used for future energy optimization.

La présence de défauts sur les surfaces des failles tectoniques peut modifier le comportement de la rupture sur ces interfaces. Cependant, le rôle de ces hétérogénéités reste difficile à quantifier du fait de la résolution limitée de l’imagerie des failles en profondeur. Une approche analogique permettant de préciser l’impact des hétérogénéités dans la propagation de la fracture est présentée ici. Cette analyse repose, tout d’abord, sur l’utilisation d’un montage expérimental assurant le suivi de la propagation d’une fracture sous contrainte de traction normale au plan de rupture (mode I). Le dispositif utilisé, mettant en jeu un suivi acoustique et optique de l’avancée du front de fracture, nous amène à déterminer l’impact des aspérités sur le partitionnement de l’énergie entre processus sismiques et asismiques. Nous faisons le lien entre efficacité de radiation et vitesse de rupture, localement perturbée par la présence de microstructures le long de l’interface. Afin d’étendre nos résultats à d’autres modes de rupture, plus fréquemment observés lors de ruptures le long de failles tectoniques, nous nous intéressons à l’adaptation de notre montage expérimental pour l’observation d’une fracture se propageant en mode de cisaillement (mode III). L’analyse des propriétés morphologiques et dynamiques de l’avancée d’un front de rupture en mode III révèle des résultats semblables à ceux obtenus en mode I. Cela suggère que les résultats obtenus en mode I peuvent être étendus aux autres modes de ruptures. / The presence of defaults on the surface of tectonic faults can affect the behaviour of the rupture along those interfaces. However, because of the limited resolution of the faults imaging at depth, the implication of these heterogeneities remains hard to quantify. We present here an analogic approach enabling the precision of the impact of the heterogeneities on the fracture propagation. On one hand, this analysis lays on the use of an experimental setup ensuring the monitoring of a fracture propagating under an imposed stress, normal to the rupture interface (mode I). The used model, implying an acoustic and an optical monitoring of the fracture front advance, leads us to the determination of the impact of asperities on the energy partitioning between seismic and aseismic processes. We make the link between radiation efficiency and rupture velocity, locally affected by the presence of microstructures along the interface. On another hand, to extend our results to other rupture modes, which are observed more often during rupture on tectonic faults, we get interested in the adaptation of our experimental setup for the observation of a fracture propagating under shear stress (mode III). The analysis of morphologic and dynamic properties of the mode III crack advance shows results similar to those obtained for mode I. This suggests eventually that the results observed in mode I can be extended to other rupture modes.

The N-acetyl-L-methionine (NALM) molecule is a methionine (Met) derivative produced via acetylation of the L-Met α-amino group with an N-acetyl group. This molecule has been shown to be bioavailable and capable of fulfilling the dietary requirement for Met in animals and humans. The current experiment was conducted to test a hypothesis that lactating dairy cows fed with NALM would increase milk production by increasing N and energy utilization efficiencies in a dose dependent manner. Eight multiparous Holstein cows that were mid lactation (124 ± 13 days-in-milk) with similar milk production were used in a 4 x 4 Latin square design for 84 d. A developmental NALM product from CJ CheilJedang (Seoul, South Korea) was used as the supplemental source of rumen-protected Met in the present study. Four dietary treatments included 0 g (control), 15 g, 30 g, and 45 g/d/cow of NALM supplementation. Supplementing NALM significantly increased dry matter intake (linear effect; P < 0.01), while milk yield tended to increase quadratically (P = 0.07). A linear decrease in milk fat concentration was seen due to supplementation of NALM in relation to the control ration (P = 0.02). However, milk fat yield was similar across treatments. A trend toward an increase in milk protein yield was observed between the control ration and the ration supplemented with 45 g of NALM (1.18 vs. 1.21 kg/d; P = 0.10). There were no differences in energy-corrected or 3.5% fat-corrected milk yields in response to treatments. It is likely that the supplementation of NALM to mid to late lactating dairy cows may have shifted nutrient and energy utilization toward tissue gain and lactation, which resulted in a decrease in feed efficiency for lactation (P = 0.02). Overall results from the present study suggest that supplementing NALM to mid to late lactating cows can increase milk yield in a dose dependent manner with a shift of net energy partitioning toward milk production and body weight gain. In addition, supplementing NALM increased milk nitrogen (N) output without affecting urinary N excretion.

Force fields have been an integral part of computational chemistry for decades, providing invaluable insight and facilitating the better understanding of biomolecular system behaviour. Despite the many benefits of a force field, there continue to be deficiencies as a result of the classical architecture they are based upon. Some deficiencies, such as a point charge electrostatic description instead of a multipole moment description, have been addressed over time, permitted by the ever-increasing computational power available. However, whilst incorporating such significant improvements has improved force field accuracy, many still fail to describe several chemical effects including polarisation, non-covalent interactions and secondary/tertiary structural effects. Furthermore, force fields often fail to provide consistency when compared with other force fields. In other words, no force field is reliably performing more accurately than others, when applied to a variety of related problems. The work presented herein develops a next-generation force field entitled FFLUX, which features a novel architecture very different to any other force field. FFLUX is designed to capture the relationship between geometry and energy through a machine learning method known as kriging. Instead of a series of parameterised potentials, FFLUX uses a collection of atomic energy kriging models to make energy predictions. The energies describing atoms within FFLUX are obtained from the Interacting Quantum Atoms (IQA) energy partitioning approach, which in turn derives the energies from the electron density and nuclear charges of topological atoms described by Quantum Chemical Topology (QCT). IQA energies are shown to provide a unique insight into the relationship between geometry and energy, allowing the identification of explicit atoms and energies contributing towards torsional barriers within various systems. The IQA energies can be modelled to within 2.6% accuracy, as shown for a series of small systems including weakly bound complexes. The energies also allow an interpretation of how an atom feels its surrounding environment through intra-atomic, covalent and electrostatic energetic descriptions, which typically are seen to converge within a ~7 - 8 A horizon radius around an atom or small system. These energy convergence results are particularly relevant to tackling the transferability theme within force field development. Where energies are seen to converge, a proximity limit on the geometrical description needed for a transferable energy model is defined. Finally, the FFLUX force field is validated through successfully optimising distorted geometries of a series of small molecules, to near-ab initio accuracy.

Submitted by Jordan (jordanbiblio@gmail.com) on 2017-05-04T16:12:04Z No. of bitstreams: 1 DISS_2015_Lucas Peres Angelini.pdf: 1371602 bytes, checksum: 257a12a7b2421c18c845019a574d2306 (MD5) / Approved for entry into archive by Jordan (jordanbiblio@gmail.com) on 2017-05-04T16:13:36Z (GMT) No. of bitstreams: 1 DISS_2015_Lucas Peres Angelini.pdf: 1371602 bytes, checksum: 257a12a7b2421c18c845019a574d2306 (MD5) / Made available in DSpace on 2017-05-04T16:13:58Z (GMT). No. of bitstreams: 1 DISS_2015_Lucas Peres Angelini.pdf: 1371602 bytes, checksum: 257a12a7b2421c18c845019a574d2306 (MD5) Previous issue date: 2015-05-21 / CAPES / As cidades são as áreas mais densamente povoadas da Terra e continuarão a ser as paisagens artificiais mais utilizadas pela maior parte da população. A substituição de vegetação nativa por superfícies artificiais em áreas urbanas é um dos impactos humanos mais irreversíveis na Terra. O monitoramento da sazonalidade e variação espacial do clima urbano é um desafio para pesquisadores e tomadores de decisão. Com poucas estações meteorológicas, torna-se impossível a medição adequada de variáveis climáticas por meio de abordagens tradicionais. O sensoriamento remoto é uma ferramenta alternativa e efetiva para o monitoramento do clima urbano por obter padrões climáticos representativos de toda a malha urbana, fornecendo informações espaço-temporais consistentes a um menor custo. O objetivo deste trabalho foi estudar a variação temporal e espacial do balanço de radiação e energia em área urbana por técnicas de sensoriamento remoto. O albedo da superfície no solo exposto foi significativamente maior do que dos demais tipos de uso do solo. As áreas de vegetação densa apresentaram valores significativamente maiores de calor latente e evapotranspiração. O Saldo de radiação apresentou diferença significativa entre as estações, sendo maior na estação chuvosa em até 37,5% para o solo exposto e 31, 9% para o asfalto. A evapotranspiração em área construída foi até 80,5% maior na estação seca para o solo exposto e 59,9% maior para área construída. Com o aumento do albedo da superfície ocorre a redução no saldo de radiação, todavia, com o aumento do NDVI houve uma diminuição no albedo da superfície tanto nas estações chuvosa e seca. A substituição de vegetação nativa por áreas alteradas como construções afetou os balanços de radiação e energia. As estimativas dos balanços de radiação e energia por sensoriamento remoto indicaram ser adequadas para avaliar os efeitos do uso do solo no microclima urbano. / Cities are the most dense populated areas on the Earth and will continue to be artificial landscapes most used by the majority of the population. The replacement of native vegetation with artificial surfaces in urban areas is one of the human irreversible impact on the earth. The monitoring of seasonal and spatial variation of urban climate is a challenge for researchers and decision makers. With few weather stations, it is impossible to adequately measuring climatic variables through traditional approaches. Remote sensing is an alternative and effective tool for monitoring the urban climate to obtain representative weather patterns of the whole urban area, providing spatial and temporal information consistent at a lower cost. The objective of this work was to study the temporal and spatial variation of radiation and energy balance in urban areas by remote sensing techniques. The surface albedo in bare soil was significantly higher than that of other types of land use. The areas of dense vegetation had significantly higher values of latent heat and evapotranspiration. The radiation balance showed a significant difference between the seasons, being higher in the rainy season in up to 37.5% for the above bare soil and 31, 9% to the asphalt. Evapotranspiration in built up area was 80.5% higher in the dry season for bare soil and 59.9% higher for building area. With the increase of surface albedo is to reduce the net radiation, however, with the increase of NDVI there was a decrease in surface albedo both wet and dry seasons. The replacement of native vegetation in disturbed areas such as buildings affected the radiation and energy balance sheets. Estimates of radiation and energy balances for remote sensing indicated be appropriate to assess the effects of land use in the urban microclimate.

Modern tools, nontraditional datasets and a better understanding of the interaction between climate and ecohydrology are continuously being developed as today's society is in critical need for improving water management, predicting hydrometeorological hazards and forecasting future climate. In particular, the study of the intra- and inter-annual variations in grass productivity and evapotranspiration caused by variations in precipitation/soil moisture and other biophysical factors is of great significance due to their relation to future climatic changes. The research presented here falls in three parts. In the first part of the dissertation, a land use adaptable model, based on the superposition of the temperature and water vapor pressure effects, is proposed for the effective clear sky emissivity. Ground radiometer and meteorological data, applicable in the subtropical climate of Saint Johns River Water Management District, Florida, were utilized for the model development over the spring season of 2004. The performance of this model was systematically evaluated by pertinent comparisons with previously established models using data over various land covers. The second part of the thesis investigates the dynamics of evapotranspiration with respect to its significant environmental and biological controls over an unmanaged bahia grassland. Eddy correlation measurements were carried out at a flux tower in Central Florida over the annual course of 2004. The main focus was on the sensitivity of the water vapor flux to wetness variables, namely the volumetric soil water content and the current precipitation index. It was shown that the time scales involved with the dynamics of evapotranspiration were on the order of six days, suggesting that depletion of the soil moisture was mostly responsible for the temporal fluctuations in evapotranspiration. Finally, simple models for the Priestley-Taylor factor were employed in terms of water availability, and the modeled results closely matched the eddy covariance flux values on daily time scale during all moisture conditions. In the third part of this work, the partitioning between latent and sensible heat fluxes was systematically examined with respect to biophysical factors. It was found that the seasonal variations in leaf area index, soil water content and net radiation were reflected in a strong seasonal pattern of the energy balance. Calculations of the bulk parameters, namely Priestley-Taylor parameter and decoupling coefficient, indicated that evapotranspiration of this grassland was controlled by water supply limitations and surface conductance. At an annual basis, the cumulative evapotranspiration was 59 percent of the precipitation received at the site. The results of this research complemented with other studies will promote better understanding of land-atmosphere interactions, accurate parameterizations of hydroclimatic models, and assessment of climate impact of grassland ecosystems.