The complex interaction between predators and their prey is rarely preserved in the fossil record. However, predation of marine mollusks by drilling gastropods leaves a diagnostic hole in the shell of the prey, possibly allowing for quantitative analysis of this ecological interaction. Drilling frequency, as measured in marine mollusks both in the Modern and fossil record, has been heralded as a potential opportunity to quantify these ecological interactions and use these values in the testing of hypotheses. This study employed the collection, tallying, and analysis of bulk samples derived from shelly deposits on 45 Modern beaches along the contiguous coast of the southeast United States (Virginia Beach, VA to Port Isabella, TX). The tallying scheme allowed for pooling and reduction of the data to compare drilling frequencies at several taxonomic and geographic scales. In addition, multivariate clustering analyses was used to generate groups of similar taxonomic abundances for direct comparison. Understanding potential spatial variation in the natural environment is paramount to using quantified values of drilling frequency in temporal and spatial studies in the fossil record. Calculated drilling frequencies for bulk (location) samples ranged from 0 to over 100%. Similar ranges of drilling frequency were observed in more finely defined taxonomic groups. Calculated drilling frequency was higher in the Carolinian province as compared to the Gulf-Louisianian and Virginian provinces. No correlation between drilling frequency and latitude was observed at any scale. An area of substantially increased drilling frequency was observed along the Carolina coast, at the ecotone between the Carolinian and Virginian provinces, suggesting that some environmental condition is present and responsible for the local increase in drilling frequency. Finally, little attention has been paid to sampling techniques and their subsequent impact on the analysis of drilling frequency. As the bulk samples represent aggregate accumulations of shells from a myriad of environments, this introduces pronounced variation in the analysis that has not been previously accounted for. Statistically, much larger abundances of specimens in individual taxa, approaching 450 values for bivalves, are needed to effectively constrain this variability.

Wireline formation testers are widely used to measure in-situ fluid pressure, to retrieve reservoir fluid samples, and to estimate formation mobility. However, formation-tester measurements are invariably influenced by mud-filtrate invasion due to drilling overbalance pressure, thereby affecting the acquisition of uncontaminated fluid samples and the estimation of in-situ petrophysical properties. Moreover, in cases of stress-sensitive formations, rock mechanical deformation may take place due to the combined effects of in-situ stress, wellbore stress imposed by mud overbalance, and wellbore pressure exerted by the formation tester itself. The latter deformation causes near-borehole perturbations of porosity and permeability that are evidenced by pressure transients measured during build-up and shut-in stages of formation testing, especially when using dual-packer pressure probes. If unaccounted for, such perturbations can also bias the estimation of in-situ fluid and petrophysical properties. Conversely, the detection and quantification of elastic mechanical deformation effects on measured pressure transients can be used to infer the underlying rock elastic and petrophysical properties of the stressed formation. The purpose of this dissertation is twofold: (a) to quantify the relative effects of mud-filtrate invasion and geomechanical deformation on pressure-transient measurements acquired with dual-packer formation testers, with special emphasis on the appraisal of near-borehole porosity and permeability enhancement due to elastic mechanical deformation, and (b) to develop a new method to estimate elastic and petrophysical properties of rock formations from dual-packer pressure transients acquired in mechanically deformable rocks. Numerical simulations of mud-filtrate invasion are performed with an axialsymmetric two-phase (water-oil) method that enforces the specific boundary and source conditions of a wellbore that penetrates horizontal layers. Simulations are performed in a cylindrical system of coordinates using finite differences together with an implicit-pressure, explicit-saturation time-marching approach that also incorporates the dynamic conditions of immiscible mudcake growth due to filtration of solids at the wellbore. Laboratory experiments are conducted to further study pressure transients due to formation testing in the presence of invasion with water-base mud. Experiments include the effects of both mud circulation and mudcake on pressure-transient measurements and are performed on a variety of rock-core samples. Measurements are successfully validated with both the developed simulator and a commercial simulator, thereby lending credence to the assumed model of dynamic solid filtration. The developed mud-filtrate fluid-flow simulator is coupled with a finite-element code that assumes 2D axial-symmetric linear elasticity to quantify geomechanical deformation. Coupling of mechanical deformation with variations of porosity and permeability assumes a staggered-in-time, iteratively coupled volumetric model. We assume a dual-packer formation tester to quantify elastic deformation effects in stress-sensitive formations as a preamble to estimating in-situ elastic and petrophysical properties. It is shown that near-wellbore spatial variations of porosity and permeability due to mechanical deformation can bias the corresponding pressure-transient measurements acquired with the dual-packer formation-tester. The degree of biasing depends on the rigidity of the stressed formation. Finally, we develop a method to estimate in-situ petrophysical and elastic rock properties from pressure-transient measurements acquired with formation-testers in mechanically deformable rocks. Petrophysical and elastic properties will change in both time and space depending on the time evolution of the conditions that influence mechanical deformation. We use a commercial reservoir simulator to calculate pressure transients due to fluid pumpout in the presence of both invasion and mechanical deformation. A pre-stressed initial condition due to mud overbalance is assumed with incremental deformation due to surface force applied by the packers or probes, and active flow imposed by the formation-tester. In so doing, we consider pressure data sets acquired with both flow and observation probes during draw-down and build-up periods. For cases where a-priori information can be sufficiently constrained, our estimation method provides reliable and accurate estimates of petrophysical and elastic properties in the presence of moderate levels of random noise. / text

published_or_final_version / Applied Geosciences / Master / Master of Science

Most studies of under-bark microclimate have been restricted to observations of a few coniferous trees in wooded southern latitudes. This limitation is worrying because of emerging wood-boring pests that specialize on deciduous trees in Canada, such as emerald ash borer (Agrilus planipennis). Using a large data set that includes 60 ash trees spread across both urban and woodlot sites in 6 different Ontario locations, I found that the under-bark microclimate of deciduous trees can provide wood-boring beetles with an environment in which temperatures which differ from air temperature. On average, daily minimum under-bark temperatures are significantly warmer than air temperatures in the winter months. At temperatures low enough to cause substantial cold-temperature mortality to emerald ash borer, the difference between under-bark and air temperature can be large. In addition, I observed that the difference between daily minimum under-bark and air temperature can vary, and consequently that assumptions of a constant level of difference between the two are not valid. In the spring season, I found that daily under-bark temperature maxima on the south side of the tree are significantly warmer than air temperature maxima. This difference lead to faster predicted development times for beetles in the southern under-bark microclimate of urban trees as compared to predictions based on air temperature, suggesting that city trees may impact overall population dynamics. While it is clear that under-bark temperatures differ from air temperatures, and are important to predicting possible range and population growth of wood-boring insects, large scale measurements of microclimate conditions are not feasible. I tested the ability of a simple Newtonian cooling model to predict under-bark temperature extremes using weather station data. While the model did not predict daily under-bark temperature maxima accurately, predictions of minima were quite accurate (1.31˚C average root mean squared error), especially when compared to the errors from assuming under-bark temperature is the same as air temperature (3.20˚C average root mean squared error). I recommend use of the Newtonian cooling model to predict under-bark temperature minima of deciduous and coniferous trees.

Thesis (Ph. D.)--University of Hong Kong, 2009. / Includes bibliographical references (leaves 177-192) Also available in print.

Thesis (Ph. D.)--University of Texas at Austin, 2008. / Vita. Includes bibliographical references.

abstract: Trenchless technologies have emerged as a viable alternative to traditional open trench methods for installing underground pipelines and conduits. Pilot Tube Microtunneling, also referred to as the pilot tube system of microtunneling, guided auger boring, or guided boring method, is a recent addition to the family of trenchless installation methods. Pilot tube microtunneling originated in Japan and Europe, and was introduced to the United States in the year 1995 (Boschert 2007). Since then this methodology has seen increased utilization across North America particularity in municipal markets for the installation of gravity sewers. The primary reason contributing to the growth of pilot tube microtunneling is the technology's capability of installing pipes at high precision in terms of line and grade, in a wide range of ground conditions using relatively inexpensive equipment. The means and methods, applicability, capabilities and limitations of pilot tube microtunneling are well documented in published literature through many project specific case studies. However, there is little information on the macroscopic level regarding the technology and industry as a whole. With the increasing popularity of pilot tube microtunneling, there is an emerging need to address the above issues. This research effort surveyed 22 pilot tube microtunneling contractors across North America to determine the current industry state of practice with the technology. The survey examined various topics including contractor profile and experience; equipment, methods, and pipe materials utilized; and issues pertaining to project planning and construction risks associated with the pilot tube method. The findings of this research are based on a total of 450 projects completed with pilot tube microtunneling between 2006 and 2010. The respondents were diverse in terms of their experience with PTMT, ranging from two to 11 years. A majority of the respondents have traditionally provided services with other trenchless technologies. As revealed by the survey responses, PTMT projects grew by 110% between the years 2006 and 2010. It was found that almost 72% of the 450 PTMT projects completed between 2006 and 2010 by the respondents were for sanitary sewers. Installation in cobbles and boulders was rated as the highest risk by the contractors. / Dissertation/Thesis / M.S. Construction 2011

Orientador: Mauro Hugo Mathias / Coorientador: Gerhard Thonhauser / Banca: Edson Cocchieri Botelho / Banca: João Andrade de Carvalho Junior / Banca: José Luis Gonçalves / Banca: Behzad Elahifar / Abstract: Pre-salt basins and their exploration have become more and more frequently mentioned over the years, not just for their potential reserves, but also for the implicit challenges in terms of operations to face in order to make these fields commercially viable. Several research efforts aimed at addressing these related barriers, in which drilling optimization and efficiency are presented as a considerably complex area. The problematic is concentrated in the low drillability and in the high cost involved when drilling the pre-salt carbonates. The outcome of this research is based in studies performed on top of eight pre-salt wells, addressing drilling operational time savings referenced by benchmarks and drilling mechanics parameters choosiness. The studies were based on simulations performed with penetration rate (ROP) modeling combined with specific energy (SE). The Bourgoyne Jr. and Young Jr. (1974) ROP model was used given the high errors presented for the other models, higher than 40% and, in terms of SE, the formulations from Teale (1965) and Pessier et al. (1992) were used. All these classic literature are still present in the industry and the software Oracle Crystal Ball was used as a supportive tool for the simulations. This research yielded four important results: 1) the polycrystalline diamond compact (PDC) is the most suitable drill-bit choice for pre-salt, presenting the lowest teeth-cutters wear rate, 0.28 [%/ m]; 2) the possible spare in operational time encountered for the pre-salt operations represent a saving of approximately 13,747,550.00 [USD] for the analyzed pre-salt wells; 3) the final mathematical model developed, after the adjustments for pre-salt, foresee an improvement dropping the relative error from 36.52% to 23.12% in terms of comparing the calculated and modeled ROP with the field measured ROP... (Complete abstract click electronic access below) / Resumo: As bacias do pré-sal e sua exploração se tornaram cada vez mais mencionadas ao longo dos anos, não apenas por seu potencial de reservatório, mas também devido aos grandes desafios implícitos em termos de operações a serem enfrentados para tornar estes campos comercialmente viáveis. Várias pesquisas vêm sendo desenvolvidas visando contornar estas barreiras, das quais a otimização e eficiência de perfuração se apresentam como uma área consideravelmente complexa. A problemática se concentra nas baixas taxas de penetração e no alto custo envolvido ao se perfurar as seções dos carbonatos do pré-sal. Os resultados da pesquisa apresentados nesta tese baseiam-se em análises com oito poços do pré-sal, abordando economia de tempo operacional com base em análises referenciadas em benchmarks e escolhas de parâmetros mecânicos de perfuração. Os estudos foram baseados em simulações realizadas com modelagem de taxa de penetração (ROP) combinadas com energia específica (SE). Utilizou-se o modelo de ROP de Bourgoyne Jr.e Young Jr. (1974) face aos altos erros apresentados pelos outros modelos, superiores a 40% e, em termos de SE, utilizouse o equacionamento de Teale (1965) e Pessier et al. (1992). Todas estas literaturas classicas ainda estão presentes na indústria e o software Oracle Crystal Ball foi utilizado como uma ferramenta de apoio para as simulações. Os resultados deste trabalho mostraram quatro conclusões importantes: 1) a broca de perfuração do tipo polycrystalline diamond compact (PDC) é a mais adequada para o pré-sal, apresentando uma taxa de desgaste de dentes-cortadores de 0.28 [%/ m]; 2) a possível diminuição de tempo de operação encontrada após análises de performance de operação pode resultar em uma economia de aproximadamente 13,747,550.00 [USD] para os poços do pré-sal analisados... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor

Este trabalho visou a averiguação do status taxonômico das esponjas bioerosivas do complexo Cliona celata da América do Sul por meio de técnicas moleculares, utilizando como marcadores a subunidade I da Citocromo c oxidase (cox1) e os Espaçadores Internos Transcritos do RNAr nuclear (ITS1 e ITS2), além de testar outros marcadores. Igualmente, avaliou o grau de variabilidade morfológica encontrado nessas espécies, principalmente por meio da morfometria dos tilóstilos, a fim de estabelecer uma diagnose para elas. Ainda, tentou determinar as relações filogenéticas dessas espécies com as demais esponjas bioerosivas utilizando o gene 28S do RNAr nuclear. Foi possível determinar a existência de cinco clados de esponjas bioerosivas do complexo Cliona celata para a América do Sul, e dois outros clados não-sulamericanos, por meio dos marcadores moleculares utilizados. Embora seja discutida a validade desses clados como espécies distintas, continua impossível, por meio de caracteres morfológicos, distingui-los, e dessa forma, a proposição formal de novas espécies é evitada. Através da reconstrução filogenética do grupo, é possível verificar que as esponjas bioerosivas analisadas se apresentaram como um grupo monofilético, e se separa em três principais clados: Pione, Spirastrellidae, e Clionaidae. Por meio desta, é sugerida a alocação das espécies do complexo C. viridis e C. schimidti dentro de Spirastrella, além de ser necessária a criação de um novo gênero para alocar as espécies do novo complexo identificado aqui, o complexo C. delitrix. / This work intended the validation of the taxonomic status of boring sponges from the Cliona celata complex of South America by molecular techniques, using Cytochrome coxidase, subunit I (cox1), and Internal Transcribed Spacers (ITS) of rRNA nuclear genes as molecular markers. Additionally, the degree of morphological variation necessary to establisha correct diagnosis for the studied species was evaluated, and additional markers were tested. Finally, a phylogenetic analysis comparing this species with other boring sponges, using the 28S rRNA nuclear gene was carried out. It was possible to point out the existence of five clades of boring sponges from the C. celata complex in South America, and two more from Mexico and Australia. Although these clades can comprise new valide species, no morphological evidence was found to separate them, and thus, no formal species descriptions were presented. Through out phylogenetic analyses it was possible to conclude that boring sponges form a monophyletic group, which can be separated in three clades: Pione, Spirastrellidae, and Clionaidae. This work suggests to allocate C. viridis and C. schimidti species complexes inside Spirastrella, and to create a new genus for the new C. delitrix species complex.

Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós–Graduação em Oceanografia Biológica, Instituto de Oceanografia, 2011. / Submitted by Cristiane Gomides (cristiane_gomides@hotmail.com) on 2013-11-18T16:26:59Z No. of bitstreams: 1 Carla Luciana Teixeira dos Santos.pdf: 553016 bytes, checksum: 84c584008c6c713cd29f554d93509b29 (MD5) / Approved for entry into archive by Angelica Miranda (angelicacdm@gmail.com) on 2013-11-18T19:43:03Z (GMT) No. of bitstreams: 1 Carla Luciana Teixeira dos Santos.pdf: 553016 bytes, checksum: 84c584008c6c713cd29f554d93509b29 (MD5) / Made available in DSpace on 2013-11-18T19:43:03Z (GMT). No. of bitstreams: 1 Carla Luciana Teixeira dos Santos.pdf: 553016 bytes, checksum: 84c584008c6c713cd29f554d93509b29 (MD5) Previous issue date: 2011 / Foi analisada de julho de 2009 a junho de 2010 a variabilidade mensal e sazonal dos organismos incrustantes e perfurantes no estuário da Lagoa dos Patos, utilizando-se como substrato painéis de madeira. O período experimental foi marcado pela ocorrência do fenômeno El Niño (ENSO), tendo a primavera e o verão apresentado valores de salinidade abaixo das médias regionais, o que se refletiu em densidades muito baixas do cirripédio Balanus improvisus, no aparecimento do bivalvo de água doce Limnoperna fortunei, e na ausência de organismos perfurantes. Nestas situações de El Niño os padrões de assentamento e a variabilidade dessas comunidades se dão de maneira diferente da observada em situações de não ocorrência do fenômeno. / Monthly and seasonal variability of both fouling and boring macrobenthic fauna were analyzed from July 2009 to June 2010 inside the Patos Lagoon estuarine region, utilizing pine-wood panels as substrate. Sampling period was marked by the occurrence of an El Niño (ENSO) phenomenon, when spring and summer presented salinity values far below the regional means. This low salinity period determined extremely low densities of the barnacle Balanus improvisus, the occurrence of the fresh water invasive bivalve Limnoperna fortunei and the absence of boring species. Under El Niño situations, patterns of larvae settlement and consequent community variability are very different from that observed in periods of non-occurrence of this stochastic phenomenon.