Characterisation of the transmissivity field of a fractured and karstic aquifer, Southern France

International audienceGeological and hydrological data collected at the Terrieu experimental site north of Montpellier, in a confined carbonate aquifer indicates that both fracture clusters and a major bedding plane form the main flow paths of this highly heterogeneous karst aquifer. However, characterising the geometry and spatial location of the main flow channels and estimating their flow properties remain difficult. These challenges can be addressed by solving an inverse problem using the available hydraulic head data recorded during a set of interference pumping tests.We first constructed a 2D equivalent porous medium model to represent the test site domain and then employed regular zoning parameterisation, on which the inverse modelling was performed. Because we aim to resolve the fine-scale characteristics of the transmissivity field, the problem undertaken is essentially a large-scale inverse model, i.e. the dimension of the unknown parameters is high. In order to deal with the high computational demands in such a large-scale inverse problem, a gradient-based, non-linear algorithm (SNOPT) was used to estimate the transmissivity field on the experimental site scale through the inversion of steady-state, hydraulic head measurements recorded at 22 boreholes during 8 sequential cross-hole pumping tests. We used the data from outcrops, borehole fracture measurements and interpretations of inter-well connectivities from interference test responses as initial models to trigger the inversion. Constraints for hydraulic conductivities, based on analytical interpretations of pumping tests, were also added to the inversion models. In addition, the efficiency of the adopted inverse algorithm enables us to increase dramatically the number of unknown parameters to investigate the influence of elementary discretisation on the reconstruction of the transmissivity fields in both synthetic and field studies.By following the above approach, transmissivity fields that produce similar hydrodynamic behaviours to the real head measurements were obtained. The inverted transmissivity fields show complex, spatial heterogeneities with highly conductive channels embedded in a low transmissivity matrix region. The spatial trend of the main flow channels is in a good agreement with that of the main fracture sets mapped on outcrops in the vicinity of the Terrieu site suggesting that the hydraulic anisotropy is consistent with the structural anisotropy. These results from the inverse modelling enable the main flow paths to be located and their hydrodynamic properties to be estimated

Experimental Study on the Mechanical Properties of Concrete using Iron Waste as Partial Replacement of Fine Aggregate

Plenty of Iron waste is available from steel plant, Sohar and it will affect the environment when it is dumped in soil. Also, every year huge quantity of concrete is used for building construction in Oman. In this project work, iron waste was collected from Sohar steel plant and was mixed with concrete. The aim of this study is to determine the mechanical properties of concrete with iron waste to be compared with normal concrete. The percentages of iron waste can be added to concrete as 0%, 10%, 15% and 20% were based on literature review. For experimental work, cubes were casted with iron waste. Also, slump test was conducted to measure the workability of fresh concrete. Furthermore, density of concrete with and without iron waste was determined. Finally, compressive strength test of concrete cubes was done for C30 grade concrete. Test result shows that compressive strength is reducing by increasing iron waste percentage

The need for developing a framework for curriculum evaluation

The importance of developing a framework for curriculum evaluation will be highlighted in this article. This framework should be based on quality standards, made public and be able to be used to help different practitioners and people involved in any institution to know what their role is and the best way to evaluate the curriculum. The article will start by presenting the main theoretical issues about curriculum evaluation, the different purposes of curriculum evaluation, who should be involved in the evaluating process, the various types of evaluation, methods of gathering evaluation data, ways to show results and the keeping of records. The paper will end by presenting what a curriculum framework should include, the idea of quality standards, and suggested research towards developing a frame work for curriculum evaluation

Uma análise de design editorial do livro S.

O livro, enquanto objeto, carrega histórias e experiências através de seu design, estando sempre aberto a interpretações por parte de seus leitores. A partir disso e da experiência de estágio no Grupo LeYa, este trabalho busca abordar o design editorial enquanto ferramenta de enriquecimento da experiência de leitura. Para isso, buscou-se apresentar conceitos inerentes à produção do livro – tais como o design editorial, a coordenação editorial, estrutura do livro e projeto gráfico – e relacionados à leitura, para que fosse possível alcançar resultados satisfatórios ao analisar o livro escolhido: S., de J. J. Abrams e Doug Dorst, cuja edição brasileira foi publicada pela editora Intrínseca, é um objeto riquíssimo em termos de design devido às conversas encontradas nas margens do livro e aos materiais adicionais inseridos em seu miolo, daí a justificativa de utilizá-lo para este fim. Nesse caso, as escolhas estéticas feitas nele existem para contribuir nas diversas possíveis interpretações da história, dependendo de seu contexto, leitor e local. Após a análise, os resultados tornaram possível a conclusão de que o projeto gráfico deve ser baseado em um profundo conhecimento dos recursos que cada ferramenta gráfica possui, além de seguir as requisições dos autores, para que o resultado possa beneficiar o leitor.Instituto Politécnico de Toma

Forward Modeling and validation of a new formulation to compute self-potential signals associated with ground water flow

The classical formulation of the coupled hydroelectrical flow in porous media is based on a linear formulation of two coupled constitutive equations for the electrical current density and the seepage velocity of the water phase and obeying Onsager's reciprocity. This formulation shows that the streaming current density is controlled by the gradient of the fluid pressure of the water phase and a streaming current coupling coefficient that depends on the so-called zeta potential. Recently a new formulation has been introduced in which the streaming current density is directly connected to the seepage velocity of the water phase and to the excess of electrical charge per unit pore volume in the porous material. The advantages of this formulation are numerous. First this new formulation is more intuitive not only in terms of establishing a constitutive equation for the generalized Ohm's law but also in specifying boundary conditions for the influence of the flow field upon the streaming potential. With the new formulation, the streaming potential coupling coefficient shows a decrease of its magnitude with permeability in agreement with published results. The new formulation has been extended in the inertial laminar flow regime and to unsaturated conditions with applications to the vadose zone. This formulation is suitable to model self-potential signals in the field. We investigate infiltration of water from an agricultural ditch, vertical infiltration of water into a sinkhole, and preferential horizontal flow of ground water in a paleochannel. For the three cases reported in the present study, a good match is obtained between finite element simulations performed and field observations. Thus, this formulation could be useful for the inverse mapping of the geometry of groundwater flow from self-potential field measurements

Precision of Age Estimation in Goldlined Seabream Rhabdosargus sarba (Sparidae) from the Arabian Sea, Oman

Accurate age determination of commercial fish is vital to successful fisheries management. Reliable age determination is essential for almost all aspects of fishery research, especially for study of growth, production, population structure and dynamics. The validation of aging methods is an important step in estimating growth and longevity. This study presents the validation of otolith-reading method for age estimation of goldlined seabream Rhabdosargus sarba. A total of 1185 goldlined seabream otoliths collected from the Arabian Sea of which 350 specimens were read by two different readers for whole and sectioned otoliths. Age comparisons between whole and thin-sectioned otoliths showed agreement in age readings for age groups 2-5 years and the whole otoliths tended to give lower ages than those estimated by thin sections. APE ranged from 3 to 7% for the three readings. Common differences between readers were related to interpretation of the otolith edge type and to interpretation of the first annulus. Keywords: Sparidae, Rhabdosargus sarba, Otolith; age; average percent error; management

Training deep learning models with a multi-station approach and static aquifer attributes for groundwater level simulation: what’s the best way to leverage regionalised information?

In this study, we used deep learning models with recurrent structure neural networks to simulate large-scale groundwater level (GWL) fluctuations in northern France. We developed a multi-station collective training for GWL simulations, using both “dynamic” variables (i.e. climatic) and static aquifer characteristics. This large-scale approach offers the possibility of incorporating dynamic and static features to cover more reservoir heterogeneities in the study area. Further, we investigated the performance of relevant feature extraction techniques such as clustering and wavelet transform decomposition, intending to simplify network learning using regionalised information. Several modelling performance tests were conducted. Models specifically trained on different types of GWL, clustered based on the spectral properties of the data, performed significantly better than models trained on the whole dataset. Clustering-based modelling reduces complexity in the training data and targets relevant information more efficiently. Applying multi-station models without prior clustering can lead the models to learn the dominant station behavior preferentially, ignoring unique local variations. In this respect, wavelet pre-processing was found to partially compensate clustering, bringing out common temporal and spectral characteristics shared by all available time series even when these characteristics are “hidden” because of too small amplitude. When employed along with prior clustering, thanks to its capability of capturing essential features across all time scales (high and low), wavelet decomposition used as a pre-processing technique provided significant improvement in model performance, particularly for GWLs dominated by low-frequency variations. This study advances our understanding of GWL simulation using deep learning, highlighting the importance of different model training approaches, the potential of wavelet preprocessing, and the value of incorporating static attributes

Factors influencing the electronic government adoption among PSM in Oman: A structural equation modeling approach

The dynamic movement of electronic government (e-government) needs a clear pathway on the adoption level of stakeholders within the public sector organization. This research has identified gaps in the movement of the adoption. The respondents comprised 237 public sector managers at the ministry level who conduct e-government services in the Sultanate of Oman. A questionnaire was designed to tap into the manager's perception of the Internet's Perceived Usefulness, Perceived Credibility of technology, Intention to use the technology, and adoption of the Internet itself. Seven hypothesized relationships were tested in the structural model. An advanced quantitative data analysis using multivariate data analysis was employed. The data were analyzed using structural equation modeling (SEM) to test the causal and mediating effects of latent variables. Based on the research, the hypothesized model fit fails to be supported (p<.05). The findings support the TAM theory extremely well, whereby, all the hypothesized paths were asserted. The generated model found three significant direct paths between Perceived Usefulness, Perceived Credibility, and intention as well as between intention and adoption

Comment on "Self-potential signals associated with preferential groundwater flow pathways in sinkholes by A. Jardani, J. P. Dupont, and A. Revil

International audienceJardani et al. [2006a] (hereinafter referred to as JDR)present a self-potential survey showing circular anomaliesassociated with shallow sinkholes in a chalk karst. Theyperform various finite element modelings and data analysis,and, in particular, use a three-dimensional (3-D) version ofthe so-called dipole occurrence probability (DOI) tomography[Iuliano et al., 2002a]

Tomography of the Darcy velocity from self-potential measurements

An algorithm is developed to interpret self-potential (SP) data in terms of distribution of Darcy velocity of the ground water. The model is based on the proportionality existing between the streaming current density and the Darcy velocity. Because the inverse problem of current density determination from SP data is underdetermined, we use Tikhonov regularization with a smoothness constraint based on the differential Laplacian operator and a prior model. The regularization parameter is determined by the L-shape method. The distribution of the Darcy velocity depends on the localization and number of non-polarizing electrodes and information relative to the distribution of the electrical resistivity of the ground. A priori hydraulic information can be introduced in the inverse problem. This approach is tested on two synthetic cases and on real SP data resulting from infiltration of water from a ditch