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Through the complex function method, an analytical method for solving the circular hydraulic tunnel with double lining is proposed. The established model is based on the interaction between the surrounding rock and the primary lining, the primary lining and the secondary lining (full contact), taking internal water pressure and the support delay into account. Based on the preset boundary conditions, the equations for solving the coefficients of the relevant analytic functions can be established, and then the obtained analytical function can be used, the stress components of any point in the surrounding rock, the primary lining and the secondary lining can be solved. By comparing the numerical solution, it is found that the analytical method proposed is correct and effective. At last, the parameters are analyzed from three aspects of controlling the water pressure in the hydraulic tunnel, exchanging the elastic modulus of linings and controlling the thickness of linings, and the factors and results affecting the stress distribution of lining are discussed. The load transfer mechanism and law of the double-lined hydraulic tunnel are revealed, which provides a theoretical basis for the preliminary design and construction of the lining protection project. [ABSTRACT FROM AUTHOR]

In this work, a semi-resolved computational fluid dynamics-discrete element method is employed to study the effects of fluid–particle and particle–particle/wall interactions on particle mixing and segregation behaviors and particle dynamics with different particle sizes in a vertical pipe. There are two species of particles with the same density in the vertical pipe: d1 = 10 (species 1) and d2 = 2–7 mm (species 2), and species 2 contains both fine and coarse particles. The Stokes number Stp is introduced to characterize the effects of different particle sizes on particle dynamics. First, the particle mixing and segregation behaviors with different size ratios are qualitatively analyzed. By comparing with smaller size ratios, obvious granular plugs and stronger contact force networks occur at larger size ratios. Second, after the segregation of species 1 and 2, the differences in dynamic characteristics between fine and coarse particles are explored. The normalized autocorrelation length scale, which is the ratio of propagation length of particle velocity fluctuations and particle diameter, is significantly different from fine to coarse particles. One notable feature is that two different flow regimes are found through the radial distribution function. Furthermore, the hydrodynamic stress and collision stress are defined to study the mechanism for the differences between fine and coarse particles. The results imply that the reason for the differences is that the collision effects go beyond the hydrodynamic effects with the increase in the Stokes number. [ABSTRACT FROM AUTHOR]

The solid–fluid two-phase flow with coarse particles is an important research object in the two-phase transportation field, such as deep-sea mining. This paper adopts the resolved computational fluid dynamics-discrete element method to investigate the motion and mechanical characteristics of the coarse particles during the hydraulic collection. First, the rising process of coarse particles by combining the particle trajectory with the qualitative force analysis is analyzed during the hydraulic collection. The spiral phenomenon of the particle is found through the particle trajectory in numerical results, and the centripetal force is the reason for the spiral phenomenon of the particle. Second, the variations of the normalized fluid drag force and the rise time of particles are investigated at different fluid velocities and particle sizes. The results show that the rise of particles during hydraulic collection results from the rising and settling effects characterized by the fluid drag force and the relative gravity, respectively. Finally, appropriate particle size is recommended to save energy and improve the efficiency of hydraulic collection. In addition, the influence of the horizontal distance between coarse particles and the inlet of the suction pipe on particle rise is discussed. [ABSTRACT FROM AUTHOR]

Aims Remote sensing (RS) is a technical method for effectively capturing real-world data on a large scale. We aimed to (i) realize the time synchronization of species and environmental variables, and extract variables related to the actual growth of species based on RS in habitat suitability modeling, and (ii) provide a reference for species management. Methods Taking invasive species Ambrosia artemisiifolia in China as an example for habitat suitability modeling. Temperature and precipitation variables were calculated from the land surface temperature provided by the moderate-resolution imaging spectroradiometer (MODIS), and climate station data, respectively. Besides, other variables that directly affect the growth or reproduction of A. artemisiifolia were also included, such as the relative humidity of the previous year's flowering period (RHPFP), and the effective UV irradiance reaching the Earth's surface (UVI). The random forest method was selected to model the habitat suitability. The environmental variables and samples were divided into four-time periods (i.e. 1990–2000, 2001–2005, 2006–2010 and 2011–2016) based on sampling time. Variables from the long-time series of RS (1990–2016) and WorldClim (1960–1990) were also modeled. Important Findings It was feasible to extract environmental variables from RS for habitat suitability modeling, and was more accurate than that based on the variables from WorldClim. The potential distribution of A. artemisiifolia in 1990–2000 and 2006–2010 was smaller than that in 2001–2005 and 2011–2016. The precipitation of driest months (bio14), precipitation coefficient of variation (bio15), RHPFP and UVI were the important environmental variables that affect the growth and reproduction of A. artemisiifolia. The results indicated that the time synchronization of species and environmental variables improved the prediction accuracy of A. artemisiifolia , which should be considered in habitat suitability modeling (especially for annual species). This study can provide an important reference for the management and prevention of the spread of A. artemisiifolia. [ABSTRACT FROM AUTHOR]

Abstract Background Previous studies indicated that type 2 diabetes mellitus (T2DM) might be associated with the risk of cancer. The aim of this study was to investigate the association between T2DM and the risk of developing common cancers in a Chinese population. Methods A population-based retrospective cohort study was carried out in the Nan-Hu district of Jiaxing city, Zhejiang province, China. The incidence of cancer cases among type 2 diabetic patients were identified through record-linkage of the Diabetic Surveillance and Registry Database with the Cancer Database from January 2002 to June 2008. The standardized incidence ratio (SIR) and 95% confidence interval (CI) were estimated for the risk of cancer among the patients with type 2 diabetes. Results The overall incidence of cancer was 1083.6 per 105 subjects in male T2DM patients and 870.2 per 105 in females. Increased risk of developing cancer was found in both male and female T2DM patients with an SIR of 1.331 (95% CI = 1.143-1.518) and 1.737 (1.478-1.997), respectively. As for cancer subtypes, both male and female T2DM patients had a significantly increased risk of pancreatic cancer with the SIRs of 2.973 (1.73-4.21) and 2.687 (1.445-3.928), respectively. Elevated risk of liver and kidney cancers was only found in male T2DM patients with SIRs of 1.538 (1.005-2.072) and 4.091 (1.418-6.764), respectively. Increased risks of developing breast cancer [2.209 (1.487-2.93)] and leukemia SIR: [4.167 (1.584- 6.749) ] were found in female patients. Conclusions These findings indicated that patients with T2DM have an increased risk of developing cancer. Additional cancer screening should be employed in the management of patients with T2DM.