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Heating performance of biomass is of significant importance for the followed chemical reactions i.e. pyrolysis, gasification, combustion, etc. Corn straw (CS) is an important renewable resource. Microwave (MW) heating performances of corn straw particles affected by corn straw mass (10, 16, 22, 28 and 34 g), corn straw particle size (0.075, 0.125, 0.200, 0.355 and 0.600 mm) and microwave power (400, 450, 500, 550 and 600 W) were explored in detail in this study. It can be obtained that when the microwave powers were 400, 450, 500, 550 and 600 W, the average heating rates were 23.06, 33.19, 61.35, 88.70 and 101.46°C/min, respectively. When the corn straw particle sizes were 0.075, 0.125, 0.200, 0.355 and 0.600 mm, the average heating rates were 101.46, 61.07, 52.70, 37.34 and 56.04°C/min, respectively. When the corn straw masses were 10, 16, 22, 28 and 34 g, the average heating rates were 36.31, 46.24, 101.46, 92.95 and 46.01°C/min, respectively. Formulae were further proposed to estimate the transient temperatures of biomass particles, and the R2 values ranged from 0.984 to 0.999. [ABSTRACT FROM AUTHOR]

Fractal theory demonstrates significant merit in the feature expression of forms of matter in nature. This study uses fractal theory to study the backfill grouting of a shield tunnel. The seepage path was considered as a seepage mesh inserted into the rock-soil mass. For the fractal features of the seepage mesh, the formulas for the diffusion distance and the pressure contribution of grout were derived. The results showed that the diffusion equations of different grout patterns (Newtonian fluid and Bingham fluid) were of a uniform form after calculation, and the equations for the pressure distribution of grout with a change in radius were identical. The diffusion distance of grout increased with increasing grouting time, and there was no indication that the development of diffusion distance tended to be gradual; the downward tendency of the grout diffusion velocity was not moderated. The segment pressure increased with an increase in the diffusion distance. With a constant diffusion distance, a greater grouting pressure produced a greater segment pressure. The favorable performance of grout was attributed to an appropriate mixture ratio. An improper mixture ratio resulted in a smaller reinforcement area in the stratum, which impaired the stability of the shield tunnel. [ABSTRACT FROM AUTHOR]

Shield tunnel is widely adopted in the metro construction, and backfill grouting is the significant part. With power-law fluid grouts as the study object, a cylindrical infiltration diffusion model and spherical infiltration diffusion model are developed by applying the generalized Darcy law and theories of seepage mechanics based on the displacement effect of grout on groundwater. Through examples, the impact of factors including grouting pressure and formation permeability coefficient in the spherical displacement infiltration diffusion model on diffusion radius, flow rate, total pressure of grout in segments, and uniform equivalent pressure in grout diffusion area (grout pressure per unit area in a segment) is analyzed. The result shows that, the diffusion speed, injection flow rate and the pressure received in segments increase with an increase of the grouting pressure. Meanwhile, as the injection time increases, the flow rate of grout under conditions of different grouting pressure all decreases, and a sharp decrease exists. The diffusion speed and grouting pressure are positively correlated to the permeability coefficient, and with the increasement of the injection time, the diffusion displacement of grout in different permeability coefficient varies increasingly, the increase amplitude of the pressure acting on the segment by grout increases gradually. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the prevalence and clinical characteristics of myelinated retinal nerve fibre (MRNF) in a large teleophthalmology system. Methods: All records between January 2015 and December 2015 from Daheng Prust teleophthalmology system were reviewed by 2 ophthalmologists independently. MRNF was classified into continuous group and discontinuous group according to the relationship between MRNF patches and optic disc. The number, total area and location of MRNF patches were analysed. Concomitant ocular diseases were documented. Results: Out of 51469 subjects, MRNF was detected in 304 eyes of 263 subjects with a prevalence rate of 0.51 ± 7.1% per subject and 0.30 ± 5.4% per eye. Among 304 eyes with MRNF, 239 (78.6%) eyes were in continuous group and 65 (21.4%) eyes were in discontinuous group. Single MRNF patch was found in 249 (81.9%) eyes and multiple MRNF patches were found in 55 (18.1%) eyes. MRNF of small size was found in 150 (49.3%) eyes. The ratios of multiple MRNF patches and small-sized MRNF in the continuous group were significantly higher than those in the discontinuous group (P =.014 and P <.001). In continuous group, the MRNF patches were located most frequently in the superior region (68.6%) of the optic disc; In discontinuous group, the MRNF patches were located most frequently in the inferotemporal region (38.5%) of the retina. Epiretinal membrane (12 eyes, 3.9%) was the most common concomitant ocular disease. Conclusion: MRNF is uncommon in China. MRNF usually presents unilaterally and as a single small whitish patch that is connected with optic disc. [ABSTRACT FROM AUTHOR]