Thermochronological record of tectonic events in central and southeastern South China since the Mesozoic

This study determines the Mesozoic–Cenozoic time-temperature evolution of SE South China, presenting a fully reconstructed thermal history and a critical framework for future research on the Mesozoic–Cenozoic geotectonic evolution of SE South China. This study provides a way to examine how horizontal tectonics led to continental-scale vertical movements and basin formation, and how this may be responsible for a number of enigmatic broad mountain belts and magmatic provinces in the global geological record

Alkyl substituted cucurbit[6]uril assisted competitive fluorescence recognition of lysine and methionine in aqueous solution

The use of competitive ratiometric fluorescence indicator displacement chemosensors derived from two alkyl substituted cucurbit[6]uril-based host-guest complexes is reported. In particular, the differing binding abilities of two cucurbit[6]uril derivatives towards the target analytes led to a useful ratiometric detection signal output for the discrimination of lysine and methionine versus the other tested α-amino acids in aqueous solution

Full-scale Mathematical Model and Simulation of Marine Natural Recirculation Drum-boiler

AbstractThrough some reasonable hypothesis and simplification of conflagation, heat and mass transfer, a full-scale dynamic mathematic model of marine natural recirculation drum-boiler is established by modular modeling method via the basic working elements of objects. The dynamic feature of a certain type natural recirculation drum-boiler was studied by this model as an instance, by contrasting the simulative results and real values, the precision and real-time capability of the developed model was testified. This study was helpful for the performance research, working optimize and control strategy building of various natural recirculation drum-boilers

Matrix-based implementation and GPU acceleration of linearized ordinary state-based peridynamic models in MATLAB

Ordinary state-based peridynamic (OSB-PD) models have an unparalleled capability to simulate crack propagation phenomena in solids with arbitrary Poisson's ratio. However, their non-locality also leads to prohibitively high computational cost. In this paper, a fast solution scheme for OSB-PD models based on matrix operation is introduced, with which, the graphics processing units (GPUs) are used to accelerate the computation. For the purpose of comparison and verification, a commonly used solution scheme based on loop operation is also presented. An in-house software is developed in MATLAB. Firstly, the vibration of a cantilever beam is solved for validating the loop- and matrix-based schemes by comparing the numerical solutions to those produced by a FEM software. Subsequently, two typical dynamic crack propagation problems are simulated to illustrate the effectiveness of the proposed schemes in solving dynamic fracture problems. Finally, the simulation of the Brokenshire torsion experiment is carried out by using the matrix-based scheme, and the similarity in the shapes of the experimental and numerical broken specimens further demonstrates the ability of the proposed approach to deal with 3D non-planar fracture problems. In addition, the speed-up of the matrix-based scheme with respect to the loop-based scheme and the performance of the GPU acceleration are investigated. The results emphasize the high computational efficiency of the matrix-based implementation scheme.Comment: 32 pages, 16 figure

Flow Dynamic Analysis of Core Shooting Process through Experiment and Multiphase Modeling

Core shooting process is the most widely used technique to make sand cores and it plays an important role in the quality of sand cores as well as the manufacture of complicated castings in metal casting industry. In this paper, the flow behavior of sand particles in the core box was investigated synchronously with transparent core box, high-speed camera, and pressure measuring system. The flow pattern of sand particles in the shooting head of the core shooting machine was reproduced with various colored core sand layers. Taking both kinetic and frictional stress into account, a kinetic-frictional constitutive correlation was established to describe the internal momentum transfer in the solid phase. Two-fluid model (TFM) simulations with turbulence model were then performed and good agreement was achieved between the experimental and simulation results on the flow behavior of sand particles in both the shooting head and the core box. Based on the experimental and simulation results, the flow behavior of sand particles in the core box, the formation of “dead zone” in the shooting head, and the effect of drag force were analyzed in terms of sand volume fraction (αs), sand velocity (Vs), and pressure variation (P)