Boreholes in the vicinity of a nuclear waste repository must be reliably sealed to prevent rapid migration of radionuclide contaminated water from the vicinity of the repository to the accessible environment. Few data currently exist regarding the effectiveness of borehole sealing. The objective of this research was to assess the performance of borehole seals under laboratory conditions, particularly with regard to varying stress fields. The approach used to evaluate borehole seals was to compare flow through a sealed borehole with flow through intact rock. Granite, basalt, and tuff were tested, using either cement or bentonite as the seal material. The main conclusions reached as a result of the experiments is that currently existing materials are capable of forming high quality seals when placed under laboratory conditions. Variation of triaxial stress state about a borehole does not significantly affect seal performance if the rock is stiffer than the seal material. Temperature/moisture variations (drying) degraded the quality of cement seals significantly. Performance partially recovered upon resaturation. A skillfully sealed borehole may reasonably be expected to be as impermeable as a fractured rock mass (subject to site-specific verification). The influence of relative seal-rock permeabilities provides insight into important seal parameters. A plug one order of magnitude greater in permeability than the rock through which it passes resulted in an increase in flow through the borehole and surrounding rock of only 1 1/2 times as compared to the undisturbed rock. Since a sealed borehole and its surrounding rock are only a small part of the total rock mass, the effect is even less pronounced. One of the simplest ways to decrease flow through a seal-rock system is to increase the length of the seal. Significant remaining questions include field emplacement techniques; field vertification of plug quality; plug performance over long time periods, particularly with respect to temperature/moisture variations and chemical stability; and radionuclide sorption capabilities. Scale effects are also important, as shafts and drifts must be sealed as well as larger diameter boreholes.

No description available.

The use of reinforcing bar (rebar) anchored with resin is a common method of rock support in both hard and soft rock mining. The average bond strength, or the load that the support can sustain for a linear length of bond to the rock, is typically determined through a series of pull tests. The average value of bond strength varies widely, since it is dependent on in-situ rock properties and environment. It is an important value because it allows mine engineers to select the appropriate length and pattern spacing of installation for the support. When a stiff support, like resin-anchored rebar, is placed in a weak, soft material, such as potash, the average bond strength tends to be lower in magnitude than for a typical hard rock installation. This research was primarily aimed at determining the failure mechanism, in soft rock applications, by which the support loses adhesion and begins to fail by sliding. Results of field pull testing determined that the resin-rock bond strength was the limiting factor controlling when adhesion loss occurred. This study investigated how the bond strength may vary given a number of variables typically found in a potash mine environment. Results reported from testing did not indicate variation in the bond strength of resin anchored rebar, significant for mining applications, given changes in resin cure time, vicinity to active mining areas, or the rock type to which the resin was adjacent. Using the results of laboratory and field testing, an equation was developed to estimate load on in-situ resin anchored rebar given deformation measurements taken from the field. This equation will help determine safe limits for fracture separations opening in the backs of potash drifts. Investigating the behaviour of resin anchored rebar in potash may lead to methods to improve bond strength and calculation of factors of safety for patterned ground support.

This dissertation examines the concept of event, as found in the ontologies developed by Martin Heidegger (1889-1976) and Gilles Deleuze (1925-1995). The texts I focus on are Heidegger's Sein und Zeit (1927), "Vom Wesen des Grundes" (1928), "Vom Wesen der Wahrheit" (lecture 1930, print 1943), Beiträge zur Philosopie (vom Ereignis) (written 1936-38, but not published until 1989), and Deleuze's Différence et répétition (1968). My focus is on the way each philosopher advances an account of the event in relation to a set of key fundamental themes. For Heidegger, these are truth, difference, ground, and time-space. For Deleuze I also discuss ground and time, but focus especially on difference. Deleuze's account of difference entails a distinction between a “virtual” register of dialectical Ideas and an “actual” register of systems of simulacra, and clarifying his concept of event in relation to these plays a dominant role in my analysis. Deleuze's account of dialectical Ideas is profoundly influenced by that of the early twentieth century mathematician and philosopher, Albert Lautman (1908-1944). Lautman, in turn, developed his account through an engagement with Heidegger's early work. In Chapter V, I reconstruct the Heideggerian line of influence on Deleuze via Lautman. Beginning in the mid-1930s Heidegger understands being to be evental in nature, while difference constitutes an essential dimension of the event, though the latter point is often neglected in the scholarship. Truth, ground, and time-space articulate the structure and dynamics of being as event. For Deleuze, being is difference, but difference differentiates by way of events. Ground, time, systems of simulacra, and dialectical Ideas articulate the structure of being's evental differentiation and the genesis of worlds of beings possessing quasi-stable identities modulated by their complex relations. / McAnulty College and Graduate School of Liberal Arts; / Philosophy / PhD; / Dissertation;

In this thesis, a study of the capacity of a suggested three - dimensional Air-to-Ground cellular system is being made. The Outside Cell Interference Factor (OCIF) is being calculated through simulations for reverse and forward link using seven loops, from the interfering cells around the desired cell for different values of the maximum height of the cell and its radius. Capacity per cell as well as delay and throughput for packet data transmission was calculated for the first time through closed form equations, with the use of the load factor, the activity factor and sectoring gain using the Automatic Repeat Request (ARQ) algorithm for the correction of errors. Moreover, in this thesis, the algorithm which has been created is being analyzed and used for the simulations. Moreover, for the first time, a case study has been made involving the study of capacity of the Air – to - Ground system for the airports of Greece, in three basic scenarios in which the number of the users, the delay and the throughput per cell is being calculated. In the first scenario, we are restricting to the three major airports of the country, while in the second it expands to six airports covering from the radio-coverage side almost all Greece. In the first two scenarios the same cell radius of 175 km is being used, while in the third the radius is reduced to 100 km and the airports are increased to nineteen. In all three scenarios we assume that all the users use the same service. The voice services are also studied of 12.2 kbps and data with transmission rate 64, 128 and 384 kbps. From scenarios 1 and 2 (cell radius 175 km), it was found that we can service at the same time up to 179 voice subscribers per cell at bit rate 12.2 kbps which reduces to 33 users for video call of 64 kbps and in 18 for video call of 128 kbps. In scenario 3 (cell radius 100km),it was found that we can serve at the same time until 126 voice subscribers per cell at bit rate 12.2 kbps which reduces to 23 users for video call of the 64 kbps and in 13 for video call of 128 kbps. In scenario 3 although the capacity per cell is lower than in scenarios 1 and 2, it provides greater total capacity (for all Greece) in relation to these scenarios.

The presence and configuration of subglacial water and sediment maintain the fast flow of arterial ice streams in Antarctica and airborne ice-penetrating radar data represent a potential resource of information about the ice-bed interface. In this thesis an original contribution to the exploration of Antarctic subglacial environments is made through the analysis of airborne surveys from Evans, Institute and Möller Ice Streams, West Antarctica. The primary approach employed is the derivation of bed-returned power (BRP), a proxy for ice-bed reflectivity, which is strongly influenced by the presence of liquid water. Estimating radar englacial attenuation (EA) accurately is a critical part of BRP analysis and a modelled approach is primarily used. BRP is derived across Evans Ice Stream and shows large-scale patterns relating to hypothesised hydrological and geological contrasts at the ice-bed. These results are developed to investigate the influence of: (1) adopted EA correction; (2) the influence of assigned ice dielectric properties in modelled EA; (3) subglacial roughness and (4) the spatial scale over which BRP is derived. Some areas of high basal drag can be detected with BRP analysis, indicating that variations in subglacial hydrology are responsible for their existence. The widely-used empirical method of estimating EA by relating ice thickness to uncorrected BRP is shown to be unreliable where ice properties change along a transect. Monte Carlo error analysis of modelled EA shows that poorly constrained ice dielectric properties also result in significant BRP uncertainty. BRP beneath Institute and Möller Ice Streams is derived on catchment- and local-scales over hypothesised subglacial features. Bungenstock Ice Rise is marked with a clear BRP signal but the locations of "active" lakes, as delineated by satellite altimetry, do not. The sensitivity of idealised flow paths to surface change and grid size are investigated. Potential future research directions regarding BRP analysis are discussed.

The Baton Rouge Fault (BRF), a growth fault, traverses Baton Rouge Parish, the study area. This fault is a part of the Baton Rouge Fault System (BRFS), located in South Louisiana. There are ten aquifers in the Baton Rouge area, which are the main source of freshwater. Beds dip and thicken toward the south. Aquifers in the Baton Rouge area are disrupted by the BRF. Aquifers contain fresh water in the updip (north of the BRF) and saline water in the downdip (south of the BRF) directions. Saline water has intruded into some of the aquifers north of the BRF as a result of overpumping. It was assumed until 2000 that the BRF is acting as a leaky barrier for the movement of saline water north of the fault. Later, in 2002 two abstracts assert that this fault is acting as a conduit. The main purpose of this work was to analyze this controversy by reviewing previous literature, modeling, and chemical analysis. This work has been done using the USGS model "MOCDENSE", a density-driven 2-D fluid flow. Five different scenarios have been developed. Chemical analysis has been done using available USGS data sources and data collected by Professor Stoessell. Modeling indicates that the fault can act as either a leaky barrier or a conduit for saline water to migrate north of the fault. Chemical analysis also shows a dual role is likely.

O estudo da dependencia espacial de variaveis do solo ou da planta, atraves da teoria das variaveis regionalizadas ou geoestatistica, permite a interpretacao e a projecao dos resultados com base na estrutura da sua variabilidade natural. Com o conhecimento das posicoes relativas das amostragens ou medidas feitas a campo, a variabilidade espacial passa a ser utilizada como um fator positivo identicando interacoes importantes nas conclusoes experimentais. O estudo da variabilidade de um solo, alem de caracterizar uma regiao, pode indicar o numero e a distribuicao de amostras a serem retiradas possibilitando ainda maior detalhamento da area e dos resultados. A base para a adocao dos procedimentos geoestatisticos e sua justicativa e o entendimento e o tratamento da variavel em questao. Para aplicacao desses procedimentos e fundamental a compreensao dos instrumentos e conceitosutilizados, tais como: semivariograma, autocorrelacao, hipotese de estacionaridade, efeito pepita, patamar, alcance, anisotropia, krigagem e outros. Desta maneira o presente trabalho apresenta e discute conceitos e metodos geoestatisticos, analisando o comportamento de dados reais de duas variaveis fisicas do solo: densidade do solo e umidade do solo nas tensoes da capacidade de campo e ponto de murcha permanente, de modo a avaliar a magnitude da variabilidade espacial, as caracteristicas qualitativas ligadas a estrutura do fenomeno natural que elas representam e a estrutura de correlacao existente entre valores tomados em dois pontos adjacentes no espaco. Para tanto, foram obtidas estimativas das estatisticas, gracos e mapas de dispersao e superficie que descrevessem espacial o comportamento da variavel em estudo. Os resultados demonstram a capacidade dos metodos em informar e ajudar a compreender o comportamento dos fenomenos fornecendo informacoes para o planejamento e analise estatistica futuras. / The study of the spatial dependence of parameters of soil or plant, through the theory of regionalized variables or geostatistics, can allow the interpretation and the projection of the results based on the structure of its natural variability. Knowing the relative positions of the samplings or field measures, the spatial variability can be used as a positive factor identifying important interactions in the experimental conclusions. The study of the soil variability, besides area characterization can indicate the number and the distribution of samples that should be removed and facilitate larger details of the area and the results. The adoption of geostatistical procedures and its justification is based on the understanding and the treatment of the cited variable. To apply these procedures it is important to know the instruments and concepts used, such as: semivariogram, autocorrelation, estationarity hypothesis, effect nugget, sill, range, anisotropy, kriging and others. Thereby this work presents and discusses geostatistical concepts and methods, analyzing the behavior of true data of two physical variables of the soil: density of the soil and soil-water content in the tensions of field capacity and point of permanent withered, to evaluate the magnitude of the spatial variability, the qualitative characteristics linked to the structure of the natural phenomenon that they represent and the structure of existent correlation among values taken in two adjacent points in the space. For such analysis statistics estimates, graphs and maps of dispersion and surface, that described spatially the behavior of the variable in study were obtained. The results demonstrate the capacity of the methods in informing and helping to understand the behavior of the phenomenons supplying information for the planning and future statistical analysis.

Thesis advisor: John Sallis / This dissertation is a reading of Schelling's influential <italic>Philosophical Investigations into the Essence of Human Freedom</italic> (1809), focusing on the meaning of "grounding" and the principle of sufficient reason (called the "principle of ground" in German philosophy). One of the contributions of my dissertation is to show how Schelling's treatise frames the traditional debate about "freedom vs. determinism" in terms of system. The connection with system provides a context for the claim of determinism and shows what is at stake in denying it. I argue that the principle of ground underlies the difficulties in integrating freedom within a system. Schelling is able to resolve these difficulties by distinguishing a deterministic from a non-deterministic sense of ground. Schelling uses the non-deterministic sense of ground (ground as condition of the possibility) to connect the parts of the system without jeopardizing freedom. At the same time, Schelling reserves the deterministic sense of ground for the ultimate act of freedom, by which individual human beings determine themselves. Beyond this core argument, the dissertation contributes to Schelling scholarship by interpreting the <italic>Freedom Essay</italic> in continuity with the texts leading up to and following its publication, most of which have not yet been translated. I show how these texts help to clarify some of the most difficult passages in the <italic>Freedom Essay</italic>. In particular, I draw on Schelling's correspondence to correct a widespread misreading of the fundamental distinction between that-which-exists and the ground of existence. / Thesis (PhD) — Boston College, 2013. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Philosophy.

Diferentes práticas de manejo da cultura de cana-de-açúcar foram estudadas por meio da avaliação de propriedades físico-hídricas do solo. Os principais aspectos avaliados foram as variações da umidade do solo, temperatura do solo, fluxo de água no solo, armazenamento da água no solo e escoamento de superficial durante um período de dois anos, um de cana-planta e um de soqueira. As diferentes práticas de manejo foram: i. entrelinha com solo nu; ii. presença de cobertura vegetal na superfície do solo (palhas + ponteiros) após a colheita; e iii. presença de resíduos na superfície do solo provenientes da queima da cana antes da colheita. Algumas variáveis foram amostradas ao longo de uma transeção de 84 pontos, com o objetivo de aplicar técnicas geoestatísticas e a abordagem de espaço de estados. O efeito da cobertura vegetal na superfície do solo, como uma conseqüência da adoção da nova prática de colheita sem queima prévia da cana, reduziu as temperaturas médias na camada superficial do solo na ordem de 7 o C, evitando picos de temperatura na superfície durante o período inicial de estabelecimento da cana soca. A cobertura vegetal, contudo, afetou negativamente o desenvolvimento da cultura reduzindo o número de colmos e seu peso úmido, no presente estudo em torno de 13 %. Por outro lado, a presença da cobertura vegetal não afetou nenhum dos seguintes componentes do balanço hídrico: escoamento superficial, fluxo de água no solo no limite inferior do volume de solo em estudo e o armazenamento de água no solo, sendo o estabelecimento do balanço hídrico da cultura de cana-de-açúcar, prevalecendo estas condições, problemático principalmente devido ao fato de que o escoamento superficial e os fluxos de água no limite inferior do volume de solo considerado foram fortemente afetados pela variabilidade espacial do solo. A análise de espaço de estados aplicada à dados de umidade e temperatura do solo coletados ao longo da transeção espacial de 84 pontos, sugeriu que, em muitas situações, devido ao fato de que os dados de temperatura do solo são mais fáceis e mais rápidos de serem obtidos no campo de que os de umidade, uma medida poderia substituir a outra. Quando esta análise foi aplicada à dados de umidade do solo, matéria orgânica do solo, conteúdo de argila e estabilidade de agregados coletados ao longo da mesma transeção, foi possível identificar como uma variável se relaciona ao comportamento local de outras variáveis e estocasticamente quantificar este relacionamento, levando em consideração os erros associados às observações e ao modelo. Devido a isto, a análise de espaço de estados é uma ferramenta analítica aplicável sob condições locais no campo, podendo, potencialmente, ajudar os agricultores no manejo adequado do solo e dos recursos naturais para o aumento da produção e, simultaneamente, a qualidade do meio ambiente. / Different practices of sugarcane trash management were studied by the evaluation of soil physical and hydrological properties. The main aspects evaluated were changes in soil water content, soil temperature, soil water fluxes, soil water storage and run-off during a period of two years, corresponding to the planted sugarcane crop and the first ratoon crop. The different management practices were: i. interrow with bare soil; ii. trash mulching, maintaining harvest residues (straw + tips) on soil surface; iii. soil with residues of trash burning prior harvest. Some variables were also collected along a 84 point transect aiming to apply geostatistical techniques and state-space approach. The effect of soil surface mulching in sugarcane ratoon crops, as a consequence of the adoption of new harvest practices with no straw burning, can reduce average soil surface layer temperatures by about 7 o C, avoiding peak surface temperatures during the initial period of the ratoon crop establishment. The mulch can, however, affect negatively the crop development reducing the number of stalks and their weight, in the present case by about 13%. On the other hand, mulching did not affect any of the following water balance components: run-off, soil water fluxes at the lower soil volume limit, and soil water storage. The establishment of the water balance of the sugarcane crop, under these prevailing conditions, was problematic mainly due to the run-off and soil water flux components which were strongly affected by soil spatial variability. The state-space approach applied to soil water content and soil temperature data along the 84 point transect suggested that, in many situations, since temperature measurements are easier and quicker to be measured than those of soil water content, one measurement could replace the other. On the other hand, when the state-space analysis was applied to soil water content, soil organic matter, clay content and aggregate stability data set along the same transect, it was possible to identify a variable that relates to the local behavior of several variables and stochastically quantify that relationship accounting for both, measurement and model errors. Due to the fact that the state-space approach is an analytical tool applicable to local field conditions, it potentially helps farmers to manage soil and soil resources adequately to maximize crop production and to simultaneously improve the quality of the local environment.