Search Results (8)

This article examines the historical evolution, contemporary dynamics, and future trajectory of China’s legal and judicial framework for pangolin protection. By reviewing over seventy years of regulatory changes, case law, and policy implementation, it outlines three distinct phases: the early emphasis on pangolins as medicinal and export resources (1949–1989); the phase of conflicted protection and utilization under regulatory expansion (1989–2020); and the post-2020 shift toward judicial activism and ecological civil litigation. We then highlight the long-standing contradiction between legislative protection and continued medicinal use, particularly the centuries-old use of pangolins and their derivatives in traditional Chinese medicine, a practice still acknowledged within certain state policies and regulatory frameworks, showing how these inconsistencies enabled persistent illegal exploitation despite regulatory controls. Through systematic analysis of public court records and case databases, the policy historical records reveal a marked increase in environmental public interest litigation since 2020. These lawsuits, often attached to criminal prosecutions, signal a transition from merely punitive approaches to restorative ones—anchored in ecological valuation of species and their services. Case studies illustrate how courts now impose not only wildlife resource loss fees, but also punitive damages and compensation for ecological service function loss. The article will elaborate in detail on the distinctions and interrelations among these types of compensation. The landmark Case No.17 also demonstrates this paradigm shift, wherein courts recognized pangolins’ role in balancing forest ecosystems. However, significant challenges persist. Valuation methodologies lack uniform standards; while the ecological value of pangolins has been recognized, their inherent value as individuals has not been emphasized within the legal system; judicial discretion varies across jurisdictions; and public interest organizations remain underutilized in litigation. Moreover, while the crackdown on organized crime succeeded in curbing mass trafficking, smaller-scale violations tied to cultural consumption for medicine use persist. The article concludes that judicial innovations, such as ecological judicial restoration bases and integration into China’s draft Ecological Environment Code, offer promising pathways forward. To enhance efficacy, it calls for standardization in ecological valuation, strengthened civil society participation, and nuanced differentiation in penal strategies between minor and serious offenses. This study ultimately positions judicial reform as the cornerstone of China’s evolving pangolin conservation strategy. Full article

The moving particle semi-implicit method (MPS) has been employed to numerically simulate fluid flows. Further, some studies have used the MPS method to solve the Darcy–Brinkman equation, which also expresses fluid flow in porous media. However, these studies simulated flows only in porous media with high permeability, not in relatively low permeability. Thus, this study developed a numerical simulation method that employs Navier–Stokes equations to describe flow in surface water and the Richards equations, derived from the Darcy law and the law of conservation of mass, to describe water flow in porous media, and it uses the MPS method to discretize those equations. This numerical simulation method was then evaluated by comparing the numerical simulation results with previously obtained experimental results for fluid draining from the bottom of a column, which was first packed with silica sand saturated with water and then filled with water to 25 cm above the top surface of the sand, which had an intrinsic permeability of 1.737 × 10^–11 m², a porosity of 0.402, van Genuchten parameters of 0.231 kPa^–1 and 9.154, a residual gas saturation of 0.0, and a residual water saturation of 0.178. The numerical simulation was able to simulate the decrease in the level of the surface water above the silica sand in the column, similar to the column experimental results. However, the decrease in the saturated water in the silica sand obtained by the numerical simulation was almost consistent with the experimental results. Full article

A high-order variable-step numerical scheme is formulated for the space–time-fractional Cahn–Hilliard equation, employing the variable-step fractional BDF2 formula. The unique solvability and mass conservation at the discretization setting are established. Subject to the constraint of time-step ratios, i.e., $0.4159\le r_k\le 4.660,$ a careful analysis based on the discrete gradient structure of the fractional BDF2 formula reveals that the proposed scheme adheres to the energy dissipation law. Remarkably, the modified energy exhibits asymptotic compatibility with that of the classical Cahn–Hilliard equation. Moreover, the modified energy dissipation law of the resulting scheme for the space–time-fractional Cahn–Hilliard equation aligns asymptotically with that of the variable-step BDF2 scheme for its classical counterpart. Finally, a few numerical experiments combined with the adaptive method are presented, which confirm the accuracy and efficiency of the proposed scheme. Full article

Accurate estimation of landslide depth is essential for practical hazard assessment and risk mitigation. This work addresses the problem of determining landslide depth from satellite-derived elevation data. Using the principle of mass conservation, this problem can be formulated as a linear inverse problem. To solve the inverse problem, we present a regularization approach that computes approximate solutions and regularization parameters using the Balancing Principle. Synthetic data were carefully designed and generated to evaluate the method under controlled conditions, allowing for precise validation of its performance. Through comprehensive testing with this synthetic dataset, we demonstrate the method’s robustness across varying noise levels. When applied to real-world data from the Fels landslide in Alaska, the proposed method proved its practical value in reconstructing landslide thickness patterns. These reconstructions showed good agreement with existing geological interpretations, validating the method’s effectiveness in real-world scenarios. Full article

A physics-informed convolutional neural network (PICNN) is proposed to simulate two-phase flow in porous media with time-varying well controls. While most PICNNs in the existing literature worked on parameter-to-state mapping, our proposed network parameterizes the solutions with time-varying controls to establish a control-to-state regression. Firstly, a finite volume scheme is adopted to discretize flow equations and formulate a loss function that respects mass conservation laws. Neumann boundary conditions are seamlessly incorporated into the semi-discretized equations so no additional loss term is needed. The network architecture comprises two parallel U-Net structures, with network inputs being well controls and outputs being the system states (e.g., oil pressure and water saturation). To capture the time-dependent relationship between inputs and outputs, the network is well designed to mimic discretized state-space equations. We train the network progressively for every time step, enabling it to simultaneously predict oil pressure and water saturation at each timestep. After training the network for one timestep, we leverage transfer learning techniques to expedite the training process for a subsequent time step. The proposed model is used to simulate oil–water porous flow scenarios with varying reservoir model dimensionality, and aspects including computation efficiency and accuracy are compared against corresponding numerical approaches. The comparison with numerical methods demonstrates that a PICNN is highly efficient yet preserves decent accuracy. Full article

This study aims to investigate the pressure changes, bubble dynamics, and flow physics inside the U- and C-shaped pipes with four different gravitational directions. The simulation is performed using a 1D centerline-based mesh generation technique along with a two-fluid model in the open-source software, OpenFOAM v.6. The continuity and momentum equations of the two-fluid model are discretized using the pressure-implicit method for the pressure-linked equation algorithm. The static and hydrostatic pressures in the two-phase flow were consistent with those of single-phase flow. The dynamic pressure in the two-phase flow was strongly influenced by the effect of the buoyancy force. In particular, if the direction of buoyancy force is the same as the flow direction, the dynamic pressure of the air phase increases, and that of the water phase decreases to satisfy the law of conservation of mass. Dean flows are observed on the transverse plane of the curve regions in both C-shaped and U-shaped pipes. The turbulent kinetic energy is stronger in a two-phase flow than in a single-phase flow. Using the 1D centerline-based mesh generation technique, we demonstrate the changes in pressure and the turbulent kinetic energy of the single- and two-phase flows, which could be observed in curve pipes. Full article

Symmetries in the Physical Laws of Nature lead to observable effects. Beyond the regularities and conserved magnitudes, the last few decades in particle physics have seen the identification of symmetries, and their well-defined breaking, as the guiding principle for the elementary constituents of matter and their interactions. Flavour SU(3) symmetry of hadrons led to the Quark Model and the antisymmetric requirement under exchange of identical fermions led to the colour degree of freedom. Colour became the generating charge for flavour-independent strong interactions of quarks and gluons in the exact colour SU(3) local gauge symmetry. Parity Violation in weak interactions led us to consider the chiral fields of fermions as the objects with definite transformation properties under the weak isospin SU(2) gauge group of the Unifying Electro-Weak SU(2) × U(1) symmetry, which predicted novel weak neutral current interactions. CP-Violation led to three families of quarks opening the field of Flavour Physics. Time-reversal violation has recently been observed with entangled neutral mesons, compatible with CPT-invariance. The cancellation of gauge anomalies, which would invalidate the gauge symmetry of the quantum field theory, led to Quark–Lepton Symmetry. Neutrinos were postulated in order to save the conservation laws of energy and angular momentum in nuclear beta decay. After the ups and downs of their mass, neutrino oscillations were discovered in 1998, opening a new era about their origin of mass, mixing, discrete symmetries and the possibility of global lepton-number violation through Majorana mass terms and Leptogenesis as the source of the matter–antimatter asymmetry in the universe. The experimental discovery of quarks and leptons and the mediators of their interactions, with physical observables in spectacular agreement with this Standard Theory, is the triumph of Symmetries. The gauge symmetry is exact only when the particles are massless. One needs a subtle breaking of the symmetry, providing the origin of mass without affecting the excellent description of the interactions. This is the Brout–Englert–Higgs Mechanism, which produces the Higgs Boson as a remnant, discovered at CERN in 2012. Open present problems are addressed with by searching the New Physics Beyond-the-Standard-Model. Full article

Gas lift is a simple, reliable artificial lift method which is frequently used in offshore oil field developments. In order to enhance the efficiency of production by gas lift, it is vital to exactly predict the distribution of temperature-field for fluid within the wellbore. A new mechanistic model is developed for computing flowing fluid temperature profiles in both conduits simultaneously for a continuous-flow gas-lift operation. This model assumes steady heat transfer in the formation, as well as steady heat transfer in the conduits. A micro-units discrete from the wellbore, whose heat transfer process is analyzed and whose heat transfer equation is set up according to the law of conservation of energy. A simplified algebraic solution to our model is conducted to analyze the temperature profile. Sensitivity analysis was conducted with the new model. The results indicate that mass flow rate of oil and the tubing overall heat transfer coefficient are the main factors that influence the temperature distribution inside the tubing and that the mass flow rate of oil is the main factor affecting temperature distribution in the annulus. Finally, the new model was tested in three various wells and compared with other models. The results showed that the new model is more accurate and provides significant references for temperature prediction in gas lift well. Full article