Fracture transmissivity estimation using natural gradient flow measurements in sparsely fractured rock

2014 ◽  
pp. 169-188
Keyword(s):  
Fractured Rock ◽  
Gradient Flow ◽  
Natural Gradient ◽  
Flow Measurements ◽  
Fracture Transmissivity

New Method for Sampling Groundwater Colloids under Natural Gradient Flow Conditions

1996 ◽  
Vol 30 (10) ◽  
pp. 3094-3101 ◽  
Author(s):  
Noam Weisbrod ◽  
Daniel Ronen ◽  
Ronit Nativ
Keyword(s):  
Gradient Flow ◽  
New Method ◽  
Natural Gradient ◽  
Flow Conditions

scholarly journals Natural Gradient Flow in the Mixture Geometry of a Discrete Exponential Family

Entropy ◽  
2015 ◽  
Vol 17 (6) ◽  
pp. 4215-4254 ◽  
Author(s):  
Luigi Malagò ◽  
Giovanni Pistone
Keyword(s):  
Exponential Family ◽  
Gradient Flow ◽  
Natural Gradient

Predictions of the wetting of bentonite emplaced in a crystalline rock based on generic site characterization data

2018 ◽  
Vol 482 (1) ◽  
pp. 285-300 ◽  
Author(s):  
S. Baxter ◽  
D. Holton ◽  
S. Williams ◽  
S. Thompson
Keyword(s):  
Host Rock ◽  
Fractured Rock ◽  
Crystalline Rock ◽  
Spent Fuel ◽  
Rock Interaction ◽  
Buffer Material ◽  
Fracture Transmissivity ◽  
Interaction Experiment

AbstractA geological disposal facility (GDF) is the widely accepted long-term solution for the management of higher-activity radioactive waste. It consists of an engineered facility constructed in a suitable host rock. The facility is designed to inhibit the release of radioactivity by using a system consisting of engineered and natural barriers. The engineered barriers include the wasteform, used to immobilize the waste, the waste disposal container and any buffer material used to protect the container. The natural barrier includes the rocks in which the facility is constructed. The careful design of this multi-barrier system enables the harmful effects of the radioactivity on humans and biota in the surface environment to be reduced to safe levels.Bentonite is an important buffer material used as a component of a multi-barrier disposal system. For example, compacted bentonite rings and blocks are used to protect the copper container, used for the disposal of spent fuel, in the KBS-3 disposal system. As the bentonite saturates, through contact with groundwater from the host rock, it swells and provides a low hydraulic conductivity barrier, enabling the container to be protected from deleterious processes, such as corrosion. The characteristic swelling behaviour of bentonite is due to the presence of significant quantities of sodium montmorillonite.Recently, there have been detailed in situ experiments designed to understand how bentonite performs under natural conditions. One such experiment is the Buffer–Rock Interaction Experiment (BRIE), performed at the Äspö Hard Rock Laboratory near Oskarshamn in the SE of Sweden. This experiment is designed to further understand the wetting of bentonite from the groundwater flow in a fractured granite host rock.In this paper, the observations from the BRIE are explained using an integrated model that is able to describe the saturation of bentonite emplaced in a heterogeneous fractured rock. It provides a framework to understand the key processes in both the rock and bentonite. The predictive capability of these models was investigated within the context of uncertainties in the data and the consequence for predictions of the wetting of emplaced bentonite. For example, to predict the wetting of emplaced bentonite requires an understanding of the distribution of fracture transmissivity intersecting the bentonite. A consequence of these findings is that the characterization of the fractured rock local to the bentonite is critical to understanding the subsequent wetting profiles. In particular, prediction of the time taken to achieve full saturation of bentonite using a simplified equivalent homogeneous description of the fractured host rock will tend to be too short.

Characterization of suspended particles collected in groundwater under natural gradient flow conditions

1992 ◽  
Vol 28 (5) ◽  
pp. 1279-1291 ◽  
Author(s):  
D. Ronen ◽  
M. Magaritz ◽  
U. Weber ◽  
A. J. Amiel ◽  
E. Klein
Keyword(s):  
Gradient Flow ◽  
Suspended Particles ◽  
Natural Gradient ◽  
Flow Conditions

Characterisation of Suspended Particles and Associated Metals in Groundwater under Natural Gradient Flow Conditions*

1993 ◽  
Vol 27 (7-8) ◽  
pp. 179-186 ◽  
Author(s):  
D. Ronen ◽  
M. Magaritz ◽  
A. J. Amiel
Keyword(s):  
Organic Matter ◽  
Colloidal Particles ◽  
Colloidal Stability ◽  
Gradient Flow ◽  
Suspended Particles ◽  
Average Concentration ◽  
Saturated Zone ◽  
Natural Gradient ◽  
Flow Conditions ◽  
Anoxic Conditions

Microscale Eulerian variations in the flux, mineralogical composition and size of suspended particles have been found in a contaminated sandy aquifer under natural gradient flow conditions () during an 8 month study period. Particle variability has been detected along a 16 m saturated section of the aquifer at a scale of centimeters and meters in the vertical and horizontal dimensions, respectively. The average concentration of particles in groundwater varied between 1 to 70 mg/l. The particles were primarily composed of CaCO3 (11% to 57%), quartz (7% to 39%) and clays (8% to 43%). Most of the particles were within the 140 to 3,000 nm size range with size modes varying from 310 to 660 nm. The large amounts of suspended particles are considered to be related to high inputs of dissolved organic carbon into groundwater from sewage effluents which have been used for agricultural irrigation since the early 1960's. As a result of organic matter biodegradation in the saturated zone, anoxic conditions developed and the pCO2 content of groundwater increased dramatically. It is postulated that part of the carbonate cement of the rocks dissolved and detrital CaCO3, quartz and clay were released as colloidal particles. In the prevailing anoxic conditions of groundwater at the study site (DO < 1 mg/l) colloidal stability is enhanced by organic matter coating of particles. The transport of metals associated with suspended particles in the saturated zone and the interaction of these particles in the aquifer environment have been ascertained through a comparison of the distribution coefficient of 17 elements as a function of depth. *Contribution No. 61, Department of Environmental Sciences and Energy Research, The Weizmann Institute of Science.

scholarly journals Quantum Statistical Learning via Quantum Wasserstein Natural Gradient

2021 ◽  
Vol 182 (1) ◽  
Author(s):  
Simon Becker ◽  
Wuchen Li
Keyword(s):  
Statistical Learning ◽  
Parameter Space ◽  
Information Matrix ◽  
Gradient Flow ◽  
Continuous Variable ◽  
Quantum States ◽  
Parametric Models ◽  
Natural Gradient ◽  
Wasserstein Metric ◽  
Density Operators

AbstractIn this article, we introduce a new approach towards the statistical learning problem $$\mathrm{argmin}_{\rho (\theta ) \in {\mathcal {P}}_{\theta }} W_{Q}^2 (\rho _{\star },\rho (\theta ))$$ argmin ρ ( θ ) ∈ P θ W Q 2 ( ρ ⋆ , ρ ( θ ) ) to approximate a target quantum state $$\rho _{\star }$$ ρ ⋆ by a set of parametrized quantum states $$\rho (\theta )$$ ρ ( θ ) in a quantum $$L^2$$ L 2 -Wasserstein metric. We solve this estimation problem by considering Wasserstein natural gradient flows for density operators on finite-dimensional $$C^*$$ C ∗ algebras. For continuous parametric models of density operators, we pull back the quantum Wasserstein metric such that the parameter space becomes a Riemannian manifold with quantum Wasserstein information matrix. Using a quantum analogue of the Benamou–Brenier formula, we derive a natural gradient flow on the parameter space. We also discuss certain continuous-variable quantum states by studying the transport of the associated Wigner probability distributions.

Groundwater Flow Quantification in Fractured Rock Boreholes Using Active Distributed Temperature Sensing Under Natural Gradient Conditions

2019 ◽  
Vol 55 (4) ◽  
pp. 3285-3306 ◽  
Author(s):  
Carlos H. Maldaner ◽  
Jonathan D. Munn ◽  
Thomas I. Coleman ◽  
John W. Molson ◽  
Beth L. Parker
Keyword(s):  
Groundwater Flow ◽  
Fractured Rock ◽  
Temperature Sensing ◽  
Flow Quantification ◽  
Natural Gradient ◽  
Distributed Temperature Sensing
Sign in / Sign up

Export Citation Format

Share Document