The Chalk Line (1934), a yearbook published by the students of East Tennessee State University, known then as East Tennessee State Teachers College. / https://dc.etsu.edu/yearbooks/1016/thumbnail.jpg

The Chalk Line (1936), a yearbook published by the students of East Tennessee State University, known then as East Tennessee State Teachers College. / https://dc.etsu.edu/yearbooks/1018/thumbnail.jpg

Despite a slow start freshwater meiofauna research is now gathering pace. Evidence is accumulating which indicates the importance of their inclusion in lotic metazoan studies. Here I contribute towards this research effort by conducting an investigation of meiofauna and macrofauna from a chalk stream. I sampled meiofauna for a 19 month period, and macrofauna for a 12 month period between April 2004 and October 2005 from the subsurface, macrophyte stands and gravel beds. The chalk stream community was highly diverse with 57 taxa identified from the subsurface and 186 from the benthos. Meiofauna outnumbered macrofauna in all habitats in terms of density. Both meio- and macroinvertebrates preferred macrophyte stands over gravel beds as habitat, indicated by higher densities, biomass and species richness. Speciesabundance relationships and density-size spectra indicated the invertebrate assemblages of the benthos to be stable over the period of the study as patterns varied little between sampling months and habitats. Production and standing biomass were dominated by the macroinvertebrates which suggests meiofauna had a limited role within functioning of the stream. However, gut content data indicated meiofauna may play an important trophic role, linking basal resources and top consumers. Combined gut content and stable isotope analysis suggested a strong pattern of generalist feeding throughout the whole spectrum of body size in the community, rejecting the concept of functional feeding groups. Predominance of generalist feeding also suggested a large number of weak interactions in food webs. While higher species richness lower in food webs indicated greater functional redundancy of lower trophic levels. Density-body size distributions were shallow with a biased distribution of energy towards larger size classes. Moreover, testing of production, standing biomass and PIB body size allometry was inconclusive with regards to theoretical predictions. The interrelationship ofbiodiversity, stability, and trophic dynamics, with body size determine the structure and dynamics of the chalk stream community, not metabolism.

This study addresses the criticism leveled at A.C.T. Mathematics teachers with regard to their failure to use any other method of teaching than chalk-and-talk. By considering the changed needs of society for mathematics and the changed perceptions by society of education, the criticism is placed in context. The importance of spatial ability for mathematics is examined in the context of theories of cognitive abilities and its current under utilization within the classroom. On the basis of the increased need to utilize more talent the study was designed to operationalise in the classroom the constructs of simultaneous and successive synthesis, derived from Luria's model of brain functioning. The question of gender differences in mathematics achievment and spatial ability is addressed. The possible role of the maturation of language in determining differences in the acquistion of ability to form simultaneous synthesis is briefly discussed. The study was designed to utilize and enhance simultaneous synthesis. By demonstrating an Aptitude-Treatment Interaction it was intended to confirm that students, who function at a high level in simultaneous synthesis but at a low level in successive synthesis, would achieve more with experience with spatial activates than in a more traditional chalk-and-talk classroom. Gender differences in achievement were not found. Gender differences in successive/simultaneous profiles were found in accordance with theory predictions. The need for the duration of longer treatment periods is briefly discussed in the context of funding and the appearance of greater efficiency of traditional teaching methods when the students are functioning at the highest level of symbolic thought.

La thèse se présente comme un bilan de plus de 25 ans de fréquentation de la craie, dans divers domaines, principalement dans le domaine pétrolier. La phénoménologie du comportement de ce matériau atypique craie est présentée dans ses divers contextes, dans une optique pluridisciplinaire. Le mémoire comprend quatre parties principales : -la première partie concerne la craie en elle-même: sa constitution, sa répartition stratigraphique et géographique, sa structure, ses propriétés physiques et pétrophysiques générales; -la deuxième partie pose les problèmes des réservoirs pétroliers de Mer du Nord; -la troisième partie, la plus volumineuse, aborde le comportement mécanique de la craie comme roche réservoir; -la quatrième partie expose certains développements en cours et considère les perspectives de développements futurs.

Estimating the impacts of climate change on groundwater represents one of the most difficult challenges faced by water resources specialists. One difficulty is that simplifying the representation of the hydrological system, or using too simple climate change scenarios often leads to discrepancies in projections. Additionally, these projections are affected by uncertainties from various sources, and these uncertainties are not evaluated in previous studies. In this context, the objective of this study is to provide an improved methodology for the estimation of climate change impact on groundwater reserves, including the evaluation of uncertainties. This methodology is applied to the case of the Geer basin catchment (480 km²) in Belgium. A physically-based surface-subsurface flow model has been developed for the Geer basin with the finite element model HydroGeoSphere. The simultaneous solution of surface and subsurface flow equations in HydroGeoSphere, as well as the internal calculation of the actual evapotranspiration as a function of the soil moisture at each node of the defined evaporative zone, improve the representation and calibration of interdependent processes like recharge, which is crucial in the context of climate change. Fully-integrated surface-subsurface flow models have recently gained attention, but have not been used in the context of climate change impact studies. This surface-subsurface flow model is combined with advanced climate change scenarios for the Geer basin. Climate change simulations were obtained from six regional climate model (RCM) scenarios assuming the SRES A2 greenhouse gases emission (medium-high) scenario. These RCM scenarios were statistically downscaled using two different methods: the 'Quantile Mapping Biased Correction' technique and a 'Weather Generator' technique. Both of them are part of the most advanced downscaling techniques. They are able to apply corrections not only to the mean of climatic variables, but also across the statistical distributions of these variables. This is important as these distributions are expected to change in the future, with more violent rainfall events, separated by longer dry periods. The 'quantile mapping bias-correction' technique generate climate change time series representative of a stationary climate for the periods 2011-2040, 2041-2070 and 2071-2100. The 'CRU' weather generator is used to generate a large number of equiprobable scenarios simulating full transient climate change between 2010 and 2085. All these scenarios are applied as input of the Geer basin model. The uncertainty is evaluated from different possible sources. Using a multi-model ensemble of RCMs and GCMs enables to evaluate the uncertainty linked to climatic models. The application of a large number of equiprobable climate change scenarios, generated with the 'weather generator', as input of the hydrological model allows assessing the uncertainty linked to the natural variability of the weather. Finally, the uncertainty linked to the calibration of the hydrological model is evaluated using the computer code 'UCODE_2005'. The climate change scenarios for the Geer basin model predict hotter and drier summers and warmer and wetter winters. Considering the results of this study, it is very likely that groundwater levels and surface flow rates in the Geer basin will decrease. This is of concern because it also means that groundwater quantities available for abstraction will also decrease. However, this study also shows that the uncertainty surrounding these projections is relatively large and that it remains difficult to state on the intensity of the decrease.

La craie est définie comme étant une roche carbonatée microporeuse. Cette formation est largement exploitée en Mer du Nord pour ses hydrocarbures et constitue un aquifère dans le Bassin de Paris. Les propriétés réservoirs de la Craie (propriétés matricielles) varient considérablement comme Alam et al. (2011) le soulignent pour les craies de surface et de subsurface de Mer du Nord, avec des porosités de 4 à 52 %, des perméabilités de 0,01 à 100 mD et des vitesses des ondes P sur roche saturée de 2,4 à 4,4 km.s-1.Dans le secteur d'étude (Normandie, France), pris comme analogue de terrain, 114 échantillons (Cénomanien- Santonien) ont été prélevés dans le but d'illustrer l'hétérogénéité sédimentaire et pétrophysique de la Craie. Comme en Mer du Nord, les échantillons présentent une grande variabilité des propriétés pétrophysiques : porosités () de 6,1 à 46,5 %, perméabilités matricielles (K) très faibles (0,002 mD) jusqu’à des perméabilités atypiques et très fortes (470 mD, en l’absence de fractures) et des vitesses des ondes P sur échantillon saturé s'étalant selon une gamme très étendue (1,8 à 5,5 km.s-1). Cependant, l’origine de ces hétérogénéités est encore mal comprise. L'objectif de cette étude est donc de comprendre l’influence respective des facteurs contrôlant les propriétés pétrophysiques afin d'optimiser la modélisation de ce type de réservoir.Trois modèles sédimentaires ont ici été définis avec :(1) un modèle de rampes, subdivisé en modèle de rampe argileuse avec des porosités de 34,4 à 46,5 % et des valeurs de perméabilité de 0,02 à 3 mD, et en modèle de rampe carbonatée (mudstone à grainstone) avec des porosités de 26,1 à 46,5 % et des valeurs de perméabilité de 0,04 à 6 mD,(2) un modèle de contourite (mudstone à grainstone et micro-packstone) avec des porosités de 8,3 à 45,5 % et des valeurs de perméabilité de 0,05 à 477 mD,(3) un modèle de surface de hiatus (Soupground à Hardground) avec des porosités de 6 à 36,9 % et des valeurs de perméabilité de 0,002 à 36 mD.Une classification des microtextures, basée sur l’observation au MEB de quatre critères (contenu minéralogique, fraction biogénique, fraction micritique et fraction de ciment), est proposée. À partir de ces critères, deux groupes majeurs ont été définis avec les Pure chalk microtextures et Impure chalk microtextures. Le groupe des Pure chalk microtextures reflète l’intensité des modifications subies par la craie lors de la diagenèse (taux de diagenèse qu’elle soit précoce ou tardive). Une augmentation du taux de diagenèse induit une diminution de la porosité et une augmentation des vitesses de propagation des ondes acoustiques P. En effet, les transformations qui s’opèrent au cours de la diagenèse, d’une part, réduisent la taille des espaces intergranulaires et donc font diminuer la porosité, et d’autre part, renforcent les contacts entre grains, favorisant ainsi la propagation des ondes acoustiques. Pour le groupe des Impure chalk microtextures, la présence de particules insolubles dans la matrice n’affecte pas la porosité, mais diminue la perméabilité du fait de la réduction des tailles d’accès aux pores.Par conséquent, l’héritage sédimentaire et les transformations diagénétiques, qui affectent à différents degrés les faciès sédimentaires primaires, déterminent les propriétés réservoirs et sont donc la cause de la grande variabilité de ces dernières. De plus, la répartition spatiale de ces microtextures, dépendante des conditions de dépôt (e.g. climat, distance des côtes), et des modifications diagénétiques (précoces ou tardives), n’est pas aléatoire. À partir de l’extrapolation combinée des faciès et de l’empreinte diagénétique, il serait ainsi possible de visualiser la distribution des propriétés pétrophysiques sur les falaises, et donc de visualiser l'architecture des réservoirs dans la Craie. / Chalk is defined as a microporous reservoir rock. This formation is a prolific hydrocarbon-bearing reservoir in the North Sea and is one of the main aquifers in the Paris Basin. The heterogeneity of chalk in terms of petrophysical properties (both surface and subsurface) is illustrated by porosity ranging from 4 to 52 %, permeability from 0.01 to 100 mD, and P-wave velocity on water-saturated samples from 2.4 to 4.4 km.s-1 (Alam et al., 2011).In the study area (Normandie, France), taken as an outcrop analogue, 114 samples were collected (Cenomanian – Santonian). As in the North Sea fields, these samples show great petrophysical heterogeneity: total porosity () from 6.1 to 46.5 %, very low permeability (K; 0.002 mD) to atypical high permeability (477 mD; without fractures), and P-wave velocity on water-saturated samples ranging from 1.8 to 5.5 km.s-1. However, the origin(s) of this large variation in petrophysical parameters is poorly understood. Three sedimentary models are defined here for the chalk:(1) Ramp models, subdivided into argillaceous ramp model, with porosity from 34,4 to 46.5%, and permeability from 0.02 to 3 mD, and carbonate ramp model (mudstone to packstone), with porosity from 26.1 to 46.5%, and permeability from 0.04 to 6 mD,(2) Contourite model (mudstone to grainstone and micro-packstone), with porosity from 8.3 to 45.5%, and permeability from 0.05 to 477 mD,(3) Softground to Hardground model, with porosity from 6 to 36.9%, and permeability from 0.002 to 36 mD.Each model has specific distribution in the porosity-permeability plot.A microtexture classification of the chalk is proposed, based on SEM observation of four groups of criteria (mineralogical content, biogenic fraction, micritic fraction and cement fraction). From these criteria, two major groups are defined: Pure chalk microtexture and Impure chalk microtexture. The Pure chalk microtexture group reflects the intensity of chalk modification during diagenesis (rate of diagenesis, whether early stage or not). An increase in the diagenetic rate induces a decrease in porosity and an increase in P-wave velocity. Diagenetic transformation induces a decrease in pore-space size, with better grain contact, explaining the decrease in porosity and the improved propagation of acoustic P-wave velocity. For Impure chalk microtexture group, the presence of insoluble particles in the matrix does not affect porosity but decreases permeability, due to the reduction of pore-throat size.The complex relationships between depositional inheritance and diagenetic transformation lead to variability in chalk petrophysical parameters. Spatio-temporal distribution of depositional facies and associated diagenetic transformation is not random; it depends on sedimentological condition (e.g. climate and distance to shore) and imprint of diagenetic processes (early or late stage). By extrapolating from the combined data on facies and diagenesis, the petrophysical properties of the entire cliff section can be characterised, and used to describe the reservoir architecture of the Chalk.

For the design of deep excavations, codes and standards advise to base estimates of wall deflections and ground movements on empirical data. Due to the limited number of case studies on circular excavations it is nearly impossible to find comparable projects under similar conditions. Therefore designers have to adopt conservative approaches, which predict larger ground movements than probably occur in reality and thus lead to more expensive structures and protective measures. Further uncertainty is induced for diaphragm wall shafts. The discontinuous nature of the wall due to the joints between the individual panels may cause anisotropic wall behaviour. There is a complete lack of understanding if, and how, the design of diaphragm wall shafts should consider anisotropic wall stiffness. The construction of Thames Water's Abbey Mills shaft in East London provided a unique opportunity to monitor the structural performance and the ground movements of one of the largest shafts ever built in the UK. The 71 m deep excavation penetrates a typical London strata and one third is in unweathered medium to hard Chalk. The monitoring scheme included distributed fibre optic strain sensing instrumentation and conventional inclinometers in the shaft wall to measure bending and hoop strains, as well as wall deflections during several construction stages. Further inclinometers and extensometers were installed around the shaft to monitor surface and sub-surface ground movements. The monitoring results were then compared to the initial PLAXIS design predictions. A further numerical investigation was conducted in FLAC2D which allowed a more flexible parametric study. The measured bending moments during shaft excavation exceeded the predictions mainly in the wall sections in the Chalk group. It was found that this was caused by assigning a low cohesion to the Chalk to induce conservative ground movements, so that the Chalk yielded in the analysis. In reality however, it remained elastic and hence induced larger bending moments in the wall. For future excavations in Chalk it is recommended to investigate the effect of a low and a high cohesion of the Chalk on the wall bending moment. The hoop strain measurements indicate that the shaft has undergone a three-dimensional deformation pattern during a dewatering trial prior to shaft excavation. The parametric study on wall anisotropy suggests that the shaft wall behaved like a cylindrical shell with isotropic stiffness, where the joints between the panels do not reduce the circumferential stiffness. Further numerical simulations varied the shaft wall thickness and the at rest lateral earth pressure coefficient in the Chalk. The results showed that the wall thickness has a minor influence on its deflection and hence thinner walls might be feasible for future shafts. The at rest lateral earth pressure coefficient of the Chalk appeared to be appropriately picked with 1.0 in the initial design. Above all, it was shown that wall deflections were very small with less than 4 mm. Correspondingly small ground movements were measured throughout shaft excavation. Empirical formulas on the other hand predict large settlements between 40 and 105 mm. Numerical predictions were much closer to the measurements and showed that small heaves occurred due to soil swelling caused by removal of overburden pressure. For future shaft designs it is hence advised against the use of empirical formulas derived from case studies under different conditions. It may furthermore not be necessary to implement expensive large-scale monitoring schemes, as it has been confirmed that ground movements around diaphragm wall shafts are minimal and that risks are low. The findings from this study provide valuable information for future excavations, which can be applied to the shafts constructed for the forthcoming Thames Tideway Tunnel project.

The thesis contains two separate projects: Part A and Part B. / Part A: No abstract provided. Part B: A method for measuring the complex permittivity of insulator materials at microwave frequencies is described in detail. Results of dielectric measurements using this technique are in good agreement with data from other sources. MKS units are used in this report. / Thesis / Master of Engineering (MEngr)

Paintings and drawings are the physical representations of my dialogue with the world around me. Art is how I connect to what is too large, or too vague, or too personally meaningful to express in any other way. Space and its transformation by light and color have always been central to this dialogue. I am particularly intrigued by spatial ambiguity. Space exists for us only in how it relates to us and so, space changes. One viewpoint or state of mind might make space seem freeing, while another makes the same space feel confining. Barriers are sometimes delineated, sometimes obscured. At other times, they are broken. This has a political implication which appears in my work as fissures, fences, compression, and collapse.The space of my inner self, the space outside, and the space between the two are relationships that drive what I paint and draw. My art is the place where I acknowledge the cracks in the ice and where I try to keep from falling through when the ground opens up. Shifting planes are where I try to keep my balance while peeking through the cracks and over the edge.