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

Quantum Searching via Entanglement and Partial Diffusion

In this paper, we will define a quantum operator that performs the inversion about the mean only on a subspace of the system (Partial Diffusion Operator). This operator is used in a quantum search algorithm that runs in O(sqrt{N/M}) for searching an unstructured list of size N with M matches such that 1<= M<=N. We will show that the performance of the algorithm is more reliable than known {fixed operators quantum search algorithms} especially for multiple matches where we can get a solution after a single iteration with probability over 90% if the number of matches is approximately more than one-third of the search space. We will show that the algorithm will be able to handle the case where the number of matches M is unknown in advance such that 1<=M<=N in O(sqrt{N/M}). A performance comparison with Grover's algorithm will be provided.Comment: 19 pages. Submitted to IJQI. Please forward comments/enquires for the first author to [email protected]

Dynamic Behavior Analysis of a Rotating Shaft with an Elliptical Breathing Surface Crack

Open access via the Springer Compact Acknowledgements The authors would like to thank the anonymous reviewers for their valuable suggestions that helped in improving the manuscript.Peer reviewedPublisher PD

Dispersive liquid-liquid microextraction-gas chromatography-mass spectrometric determination of polycylic aromatic hydrocarbons in water

In this work, a sample preparation method based on dispersive liquid-liquid microextraction (DLLME) coupled with gas chromatography-mass spectrometry (GC-MS) was developed for the extraction of polycyclic aromatic hydrocarbons (PAHs), namely phenanthrene and fluoranthene from water sample. In this method, a mixture of carbon tetrachloride, CCl4 (extraction solvent) and acetone (disperser solvent) was injected using a syringe into 5 mL water sample to form emulsion where the PAHs were extracted into the fine droplets of extraction solvent. The solution was then centrifuged for 3 min at 3000 rpm and the fine droplets were sedimented at the bottom of centrifuge tube. Sedimented phase (1 ?L) was injected into the GC-MS for separation and determination of PAHs. The effects of various extraction parameters namely extraction solvent type, disperser solvent type, volume of extraction solvent, and volume of disperser solvent were investigated. The optimized conditions for DLLME of selected PAHs were carbon tetrachloride as extraction solvent, 60 ?L of extraction solvent (CCl4), acetone as disperser solvent and 1 mL of disperser solvent (acetone). The correlation coefficient (r2) of the calibration curve for phenanthrene and fluoranthene were 0.9993 and 0.9973, respectively. The limits of detection (LODs) obtained for phenanthrene and fluoranthene were 0.0008 ?g/mL and 0.0006 ?g/mL, respectively. The proposed method proved to be reproducible with relative standard deviations (RSDs) of 10.69 % and 9.72 % for phenanthrene and fluoranthene, respectively. The analyte recoveries were 100.5 – 107.8 %. The concentration of was 0.02-0.15 ?g/mL. It was found that phenanthrene and fluoranthene were present in lake water sample at concentrations of 3.47×10-3 and 2.69×10-3 ?g/mL. The DLLME method combined with GC-MS proved to be an efficient method and was applied successfully for the determination of PAHs from water sampl

Least Upper Bounds of the Powers Extracted and Scattered by Bi-anisotropic Particles

The least upper bounds of the powers extracted and scattered by bi-anisotropic particles are investigated analytically. A rigorous derivation for particles having invertible polarizability tensors is presented, and the particles with singular polarizability tensors that have been reported in the literature are treated explicitly. The analysis concludes that previous upper bounds presented for isotropic particles can be extrapolated to bi-anisotropic particles. In particular, it is shown that neither nonreciprocal nor magnetoelectric coupling phenomena can further increase those upper bounds on the extracted and scattered powers. The outcomes are illustrated further with approximate circuit model examples of two dipole antennas connected via a generic lossless network.Comment: 9 pages, 1 figure