What Does the Lewis Turning Point Mean for China? A Computable General Equilibrium Analysis

We apply a computable general equilibrium framework to assess likely impacts of the Lewis turning point on China and the rest of the world. Modeling results suggest that China will probably transition from an abnormal economy to a normal economy with somewhat lower growth but higher inflation, which requires significant revision to the macroeconomic policy framework. China would lose competitiveness in laborintensive activities, its current account surplus should fall but overinvestment risk could rise. These changes in China should help improve other counties current accounts and boost lowcost countries production. The Lewis turning point, however, does not provide automatic solutions to some of the key challenges, such as service sector development and innovation capability. China will need to make serious policy efforts to avoid the socalled middle income trap.Lewis turning point, labor shortage, general equilibrium analysis, normal economy, middleâ€ÂÂincome trap

Research on the dynamic characteristics of mast mechanism of rotary drilling rig

AbstractIn order to express the inherent complex dynamic characteristics of mast mechanism of rotary drilling rig synthetically and improve the smooth-going property of key parts and related hydraulic system in the lifting process. firstly, a dynamic model of mast mechanism based on Newton-Euler method is established, then a hydraulic system model of mast mechanism based on power bond graph is built up, a set of optimal installation position parameters are got for designers to refer by analyzing and comparing the impact of the dynamic characteristics in lifting process by changing the installation position of mast mechanism. The integrated modeling method is expected to be a theoretical basis for designing the mast system of rotary drilling rig

Microscopic changing-mass model of PVA hydrogel under unidirectional compression

PVA (Polyvinyl Alcohol) hydrogel is a kind of soft materials, with nontoxic and good biocompatibility. This kind of hydrogel shows strong nonlinearity in the static compression tests because of the high water content (~60‑90%), and the water is squeezed out when the PVA hydrogel is compressed. It means that the PVA hydrogel losts the mass during compression. Aiming at the changing mass mechanism and constitution in the compression of PVA hydrogel, we established a simplified microscopic model which is a single layer frame composite structure consisting of PVA fibers, water, and virtual membrane, in which the membrane wraps outside surfaces of the cubic cells and has no mass, but its membrane force has same properties with the surface tension of water. In the model, the deformation of PVA fibers and the compressive water sustains the external stress when the PVA hydrogel is compressed. In addition, by considering the limitation of the maximum membrane force induced by compressive water, the squeezed water will be calculated in each compressive step and the mechanism of the changing mass is determined quantitatively; in the meantime, the constitution of the PVA hydrogel may be deduced

Numerical analysis of yield properties of closed-cell aluminum foam under multiaxial loads by 3D voronoi model

Metallic foam is a typical porous material whose yield surface is related to not only von Mises equivalent stress but also the hydrostatic pressure. It is essential to study the yield properties of closed-cell aluminum foam under complex loading conditions. However, because the current experimental technique may support only a few proportions of multiaxial loading, it is hard to learn the yield surface well especially for the tensile hydrostatic pressure. In this article, we explored a numerical method to learn the yield properties of aluminum foam, in which the meso structures of aluminum foam were simulated by 3D Voronoi method. In addition, the yield surface of aluminum foam was drawn successfully with the numerical method. The main works included: (1) In our numerical simulation, we tested the calculating parameters such as mass scaling, elements number, and loading velocity on simulation results and verified the homogeneity of the 3D Voronoi model firstly. Furthermore, the optimized calculating parameters were determined by considering both reliability and feasibility of the calculation. Homogeneity of 3D Voronoi model was checked by the compression behaviors of aluminum in different directions. (2) In order to overcome the difficulty to determine critical yield state of metallic foams under complex loads, we recommended criterion by setting a dimensionless plastic dissipation value to determine the onset yield state of the foam under multiaxial loads. The critical value of dimensionless plastic dissipation was deduced from the common criterion—0.2% plastic strain in uniaxial loading, and the effect of relative densities on critical values was analyzed. (3) Three normal stresses were applied on cubic aluminum foam proportionally to implement the proportional loading. The different loading proportional factors of the three normal stresses were set widely to insure the yield surface including enough data, such as the hydrostatic loads cover from minimum negative to maximum positive values; each proportion has three loading proportional factors. Further, effects of the relative density on yield surface were investigated

Short- and medium-term efficacy of sodium glucose cotransporter 2 (SGLT-2) inhibitors for the treatment of type 1 diabetes: systematic review and meta-analysis

Introduction: Sodium glucose cotransporter 2 (SGLT2) inhibitors are insulin-independent and glucose-dependent anti-hyperglycaemic drugs that have shown potential as an adjuvant therapy to insulin for the treatment of type 1 diabetes mellitus (T1DM). The purpose of this meta-analysis is to systematically collect available data from randomised trials to determine SGLT-2 inhibitor efficacy in terms of glycaemic control, body mass index, and renal protection when compared with placebo. Material and methods: Cochrane Library, MEDLINE, and EMBASE databases were searched for randomised controlled trials and metaanalyses (without language restrictions) conducted from January 2010 to September 2019. Results: Seventeen randomised controlled trials with 7325 participants were included. Sodium glucose cotransporter 2 therapy significantly reduced the level of glycated haemoglobin (HbA1c) (by 0.37%), body weight (by 2.88 kg), and estimated glomerular filtration (eGFR) (by 0.67 mL/min/1.73 m²) when compared with placebo (all outcomes, p < 0.00001). Subgroup analysis by HbA1c levels showed significant differences between six and 12 months of treatment (p < 0.1). The magnitude of the HbA1c lowering effect waned with longer duration of treatment after six months (up to 12 months). Subgroup analysis by body weight showed significant differences between 1 and 3–4 months of treatment (p < 0.1). Weight loss plateaued after 3–4 months of treatment; subsequently, the weight remained relatively stable until 12 months. Subgroup analysis by eGFR showed significant differences between six and 12 months of treatment (p < 0.1). The magnitude of the eGFR lowering effect increased with longer duration of treatment after six months (up to 12 months). Conclusions: Sodium glucose cotransporter 2 inhibitors show significant therapeutic effects when compared with placebo. Although changes in HbA1c, body weight, and eGFR vary during treatment, the therapeutic effects of SGLT-2 inhibitors measured by these three outcomes can last up to 12 months. More long-term, randomised trials and extended studies are needed to determine the long-term effects of SGLT2 inhibitors as adjuvant therapy for T1DM patients.