Simulation of rock salt dissolution and its impact on land subsidence

Extensive land subsidence can occur due to subsurface dissolution of evaporites such as halite and gypsum. This paper explores techniques to simulate the salt dissolution forming an intrastratal karst, which is embedded in a sequence of carbonates, marls, anhydrite and gypsum. A numerical model is developed to simulate laminar flow in a subhorizontal void, which corresponds to an opening intrastratal karst. The numerical model is based on the laminar steady-state Stokes flow equation, and the advection dispersion transport equation coupled with the dissolution equation. The flow equation is solved using the nonconforming Crouzeix-Raviart (CR) finite element approximation for the Stokes equation. For the transport equation, a combination between discontinuous Galerkin method and multipoint flux approximation method is proposed. The numerical effect of the dissolution is considered by using a dynamic mesh variation that increases the size of the mesh based on the amount of dissolved salt. The numerical method is applied to a 2D geological cross section representing a Horst and Graben structure in the Tabular Jura of northwestern Switzerland. The model simulates salt dissolution within the geological section and predicts the amount of vertical dissolution as an indicator of potential subsidence that could occur. Simulation results showed that the highest dissolution amount is observed near the normal fault zones, and, therefore, the highest subsidence rates are expected above normal fault zones

Adaptives Grundwassermanagement in urbanen Gebieten: Einfluss der Oberflächengewässer-Grundwasser-Interaktion am Beispiel künstlicher Grundwasseranreicherung sowie variabler In-/Exfiltration der Birs (Schweiz)

Zusammenfassung: Der Nutzungsdruck auf Grundwasserressourcen in intensiv genutzten Flussebenen wird zunehmend größer. Ziel dieses Beitrages ist, anhand eines repräsentativen, instationären Datensatzes eines urbanen Grundwassersystems (Unteres Birstal CH) aufzuzeigen, wie mit Ansätzen des adaptiven Grundwassermanagements die Voraussetzungen für die nachhaltige Nutzung von Grundwasserressourcen geschaffen werden können. Mithilfe eines instationären Grundwassermodells können spezifische Fragen der Fluss-Grundwasser-Interaktion und dem Betrieb künstlicher Grundwasseranreicherung beantwortet werden. Die Instationarität der Fluss-Grundwasser-Interaktion und eine damit zusammenhängende Änderung von In - und Exfiltrationsverhältnissen konnte für verschiedene Flussabschnitte ermittelt werden. Die Datenauswertung eines Jahrhunderthochwassers trug wesentlich zum Verständnis dieser Prozesse bei. Durch ein Experiment mit der längerfristigen Außerbetriebnahme einer künstlichen Grundwasseranreicherung im Untersuchungsgebiet konnten die Auswirkungen von geplanten Nutzungsänderungen abgeschätzt werden. Die Untersuchungen tragen zum Prozessverständnis des Grundwassersystems bei und liefern die Grundlage für eine Diskussion über lang-, mittel- und kurzfristige Ziele hinsichtlich der regionalen Bewirtschaftung urbaner Wasserressource

Patrones espectrales de variables climáticas en relación con los escurrimientos en cuencas en Sudamérica

Ponencia presentada en: II Congreso de la Asociación Española de Climatología “El tiempo del clima”, celebrado en Valencia del 7 al 9 de junio de 2001[ES]Se intenta relacionar las estructuras de variables climáticas, con los escurrimientos en la región sur de Sudamérica. Se fundamenta la estructura del espectro teórico de las series utilizando registros mayores de 40 años. Se identifican períodos relevantes en torno a los 25, 11, 9, 6, 3.5 y 2.3 años y, como proceso general, las series parecen ajustarse a modelos markovianos de primer orden. Se establecen inferencias sobre la existencia de eventos importantes para la región, como El Niño, y condiciones generales en el Pacífico. Se desarrolla una metodología para la clasificación y división en zonas homogéneas de caudales y variables climáticas específicas.[EN]We have tried to obtain relations between climatic variables structures, which are the input, with the streamflow in the south zone of Southamerica. We establish the theorical spectral structure of the series using records of more than 40 years. We could see important periods around 25, 11, 9, 6, 3.5 and 2.3 years, and, as a general process, the series seem to adjust at a first order markovian model. We establish inferences about the existence of important events for the region, as El Niño, and general conditions in the Pacific Ocean. We develop a methodology for the classification in homogeneous zones of streamflow and specific climatic variables

The prefrontal cortex of the bottlenose dolphin (Tursiops truncatus Montagu, 1821): a tractography study and comparison with the human

Cetaceans are well known for their remarkable cognitive abilities including self-recognition, sound imitation and decision making. In other mammals, the prefrontal cortex (PFC) takes a key role in such cognitive feats. In cetaceans, however, a PFC could up to now not be discerned based on its usual topography. Classical in vivo methods like tract tracing are legally not possible to perform in Cetacea, leaving diffusion-weighted imaging (DWI) as the most viable alternative. This is the first investigation focussed on the identification of the cetacean PFC homologue. In our study, we applied the constrained spherical deconvolution (CSD) algorithm on 3 T DWI scans of three formalin-fixed brains of bottlenose dolphins (Tursiops truncatus) and compared the obtained results to human brains, using the same methodology. We first identified fibres related to the medio-dorsal thalamic nuclei (MD) and then seeded the obtained putative PFC in the dolphin as well as the known PFC in humans. Our results outlined the dolphin PFC in areas not previously studied, in the cranio-lateral, ectolateral and opercular gyri, and furthermore demonstrated a similar connectivity pattern between the human and dolphin PFC. The antero-lateral rotation of the PFC, like in other areas, might be the result of the telescoping process which occurred in these animals during evolution

Semiconductor nanostructures engineering: Pyramidal quantum dots

Pyramidal quantum dots (QDs) grown in inverted recesses have demonstrated over the years an extraordinary uniformity, high spectral purity and strong design versatility. We discuss recent results, also in view of the Stranski-Krastanow competition and give evidence for strong perspectives in quantum information applications for this system. We examine the possibility of generating entangled and indistinguishable photons, together with the need for the implementation of a, regrettably still missing, strategy for electrical control

Spatio-temporal Models of Lymphangiogenesis in Wound Healing

Several studies suggest that one possible cause of impaired wound healing is failed or insufficient lymphangiogenesis, that is the formation of new lymphatic capillaries. Although many mathematical models have been developed to describe the formation of blood capillaries (angiogenesis), very few have been proposed for the regeneration of the lymphatic network. Lymphangiogenesis is a markedly different process from angiogenesis, occurring at different times and in response to different chemical stimuli. Two main hypotheses have been proposed: 1) lymphatic capillaries sprout from existing interrupted ones at the edge of the wound in analogy to the blood angiogenesis case; 2) lymphatic endothelial cells first pool in the wound region following the lymph flow and then, once sufficiently populated, start to form a network. Here we present two PDE models describing lymphangiogenesis according to these two different hypotheses. Further, we include the effect of advection due to interstitial flow and lymph flow coming from open capillaries. The variables represent different cell densities and growth factor concentrations, and where possible the parameters are estimated from biological data. The models are then solved numerically and the results are compared with the available biological literature.Comment: 29 pages, 9 Figures, 6 Tables (39 figure files in total

Groundwater, geothermal modelling and monitoring at city-scale : reviewing European practice and knowledge exchange : TU1206 COST sub-urban WG2 report

The need for cities to make more effective use of the subsurface on which they stand, is increasingly being recognised in Europe and further afield to be essential for future cities to be sustainable and more resilient [1,2]. However, city planning worldwide remains largely 2D, with very few cities having any substantial subsurface planning or Masterplans – the cities of Helsinki, Montreal, Singapore being rare exceptions [3,4]. The consequences of inadequate consideration and planning of the subsurface are far-reaching, in economic, environmental and social terms. Across Europe, poor understanding of ground conditions is recognised as the largest single cause of construction project delay and overspends [5]. Management of urban groundwater and shallow geothermal energy resources is becoming increasingly important as cities are increasingly looking to use these resources to meet current and future energy and heating and water needs. Whilst these are, alongside potential underground building space, the two most important resources for future cities, the monitoring and regulation of these resource is widely variable across Europe. For subsurface opportunities such as groundwater and geothermal energy to be realised and utilised to greatest effect to support growing city populations and infrastructure, city planners must be both aware of, and have some understanding of the resources, available data and research, and both the opportunities and risks which the resources provide to city development [6,7]. To supply this understanding to city municipalities and others, geological surveys must have robust datasets of groundwater and geothermal resources at city-scale, and the relevant knowledge and understanding from these data must be made accessible to inform subsurface planning in appropriate datasets relevant to different scale of interest in different planning stages. What density and frequency of data are required for a robust understanding of a city’s groundwater and geothermal resources will be different in different cities, according to the complexity of the resources, and the intensity of subsurface use and demands on the resources. Indeed, no one design of city-scale monitoring or modelling of ground-water and -heat resources is appropriate for all cities, or for all monitoring objectives. However, the guiding principles of good practice for developing robust city-scale monitoring, and datasets are widely applicable, as are the key principles for ensuring these data inform city planning processes. This report provides an initial review of existing examples of current practices in Europe with respect to groundwater and geothermal monitoring and modelling, as a resource for other cities to learn from and build upon. The report also provides an overview of some of the different practices used for communicating groundwater and geothermal energy data and knowledge to inform urban planning and managemen

Waveguide Coupled Resonance Fluorescence from On-Chip Quantum Emitter

Resonantly driven quantum emitters offer a very promising route to obtain highly coherent sources of single photons required for applications in quantum information processing (QIP). Realizing this for on-chip scalable devices would be important for scientific advances and practical applications in the field of integrated quantum optics. Here we report on-chip quantum dot (QD) resonance fluorescence (RF) efficiently coupled into a single-mode waveguide, a key component of a photonic integrated circuit, with a negligible resonant laser background and show that the QD coherence is enhanced by more than a factor of 4 compared to off-resonant excitation. Single-photon behavior is confirmed under resonant excitation, and fast fluctuating charge dynamics are revealed in autocorrelation g(2) measurements. The potential for triggered operation is verified in pulsed RF. These results pave the way to a novel class of integrated quantum-optical devices for on-chip quantum information processing with embedded resonantly driven quantum emitters