A new approach to upscaling fracture network models while preserving geostatistical and geomechanical characteristics

A new approach to upscaling two-dimensional fracture network models is proposed for preserving geostatistical and geomechanical characteristics of a smaller-scale “source” fracture pattern. First, the scaling properties of an outcrop system are examined in terms of spatial organization, lengths, connectivity, and normal/shear displacements using fractal geometry and power law relations. The fracture pattern is observed to be nonfractal with the fractal dimension D ≈ 2, while its length distribution tends to follow a power law with the exponent 2 < a < 3. To introduce a realistic distribution of fracture aperture and shear displacement, a geomechanical model using the combined finite-discrete element method captures the response of a fractured rock sample with a domain size L = 2 m under in situ stresses. Next, a novel scheme accommodating discrete-time random walks in recursive self-referencing lattices is developed to nucleate and propagate fractures together with their stress- and scale-dependent attributes into larger domains of up to 54 m × 54 m. The advantages of this approach include preserving the nonplanarity of natural cracks, capturing the existence of long fractures, retaining the realism of variable apertures, and respecting the stress dependency of displacement-length correlations. Hydraulic behavior of multiscale growth realizations is modeled by single-phase flow simulation, where distinct permeability scaling trends are observed for different geomechanical scenarios. A transition zone is identified where flow structure shifts from extremely channeled to distributed as the network scale increases. The results of this paper have implications for upscaling network characteristics for reservoir simulation

Ground state fidelity in bond-alternative Ising chains with Dzyaloshinskii-Moriya interactions

A systematic analysis is performed for quantum phase transitions in a bond-alternative one-dimensional Ising model with a Dzyaloshinskii-Moriya (DM) interaction by using the fidelity of ground state wave functions based on the infinite matrix product states algorithm. For an antiferromagnetic phase, the fidelity per lattice site exhibits a bifurcation, which shows spontaneous symmetry breaking in the system. A critical DM interaction is inversely proportional to an alternating exchange coupling strength for a quantum phase transition. Further, a finite-entanglement scaling of von Neumann entropy with respect to truncation dimensions gives a central charge c = 0.5 at the critical point.Comment: 6 pages, 4 figure

Ground-State Fidelity and Kosterlitz-Thouless Phase Transition for Spin 1/2 Heisenberg Chain with Next-to-the-Nearest-Neighbor Interaction

The Kosterlitz-Thouless transition for the spin 1/2 Heisenberg chain with the next-to-the-nearest-neighbor interaction is investigated in the context of an infinite matrix product state algorithm, which is a generalization of the infinite time-evolving block decimation algorithm [G. Vidal, Phys. Rev. Lett. \textbf{98}, 070201 (2007)] to accommodate both the next-to-the-nearest-neighbor interaction and spontaneous dimerization. It is found that, in the critical regime, the algorithm automatically leads to infinite degenerate ground-state wave functions, due to the finiteness of the truncation dimension. This results in \textit{pseudo} symmetry spontaneous breakdown, as reflected in a bifurcation in the ground-state fidelity per lattice site. In addition, this allows to introduce a pseudo-order parameter to characterize the Kosterlitz-Thouless transition.Comment: 4 pages, 4 figure

Designing LED array for uniform illumination based on local search algorithm

We propose a numerical optimization method based on local search algorithm to design an LED array for a highly uniform illumination distribution. In the first place, an initial LED array is randomly generated and the corresponding value of the objective function is calculated. In the second place, the value of the objective function is iteratively improved by applying local changes of the LED array until the objective function value can not be improved. This method can automatically design an array of LEDs with different luminous intensity value and distribution. Computer simulations show that the near-optimal LED array with highly uniform illumination distribution on target plane is obtained by this method

Testing of disease-resistance of pokeweed antiviral protein gene (PacPAP) in transgenic cucumber (Cucumis sativus)

Transformation of pokeweed antiviral protein gene (PAP) into plants was shown to improve plant resistance to several viruses or fungi pathogens with no much negative effect on plant growth. The non-virulent defective PAP inhibits only the virus but does not interfere with the host. A non-virulent defective PAP gene (PacPAP) from Phytolacca acinosa was introduced into cucumber successfully by agrobacterium mediated method. Southern blotting and northern blotting analyses indicated that, 5 stable transgenic cucumber lines with PacPAP were obtained and PacPAP showed different expression levels in transgenic plants. The identification of resistances to disease was performed by artificial inoculation of cucumber mosaic virus (CMV) and Fusarium oxysporum fsp. cucumerinum on T0 and T1 transgenic plants. Compared with the non-transgenic susceptible plants, all transgenic plants with PacPAP showed resistance in different degree to CMV and the CMV-resistance of progeny (T1) from transgenic lines could inherit stably, but the transgenic plants did not resist to Fusarium wilt of cucumber, the PacPAP was not resistant to Fusarium oxysporum fsp. cucumerinum. This work provides a new virus resistant cucumber breeding resource.Key Words: Pokeweed antiviral protein gene, genetic transformation, Cucumis sativu

Selective Adsorption of Tetrahydropalmatine by a Molecularly Imprinted Polymer with Modified Rosin Cross-linker

A molecularly imprinted polymer (MIP) containing a phenanthrene skeleton was prepared by suspension polymerization with ethylene glycol maleic rosinate acrylate (EGMRA) as the cross-linker,  tetrahydropalmatine (THP) as the template, and methacrylic acid as the functional monomer. A non-imprinted polymer (NIP) was similarly prepared and treated, but in the absence of THP. The MIP and NIP were   characterized by scanning electron microscopy and nitrogen sorption and thermal gravimetric analyses. The time taken by theMIPto reachTHP(C0=2.8mmolL–1) adsorption equilibrium was 4.5 h, and the recognition factor of the MIP forTHPwas 2.09. The change in microcalorimetric heat flow during adsorption revealed that the MIP had a higher affinity to THP compared with NIP. Selective adsorption experiments demonstrated the high affinity and THP selectivity of the MIP.KEYWORDS: Molecularly imprinted polymer, tetrahydropalmatine, selective adsorption, microcalorimetry, modified rosin