No abstract

The medium temperature pyrolysis process using a fixed-bed reactor at atmospheric pressure was utilised to recover carbon black from motorcycle and automobile tyres. Experimental results have shown that the ash and volatile contents of several recovered carbon blacks are high, the elongation at break of the vulcanised natural rubber filled with recovered carbon blacks from motorcycle tyres is better than that from motorcycle tyres and standard carbon black 7#, while the other mechanical properties are worse. In order to improve the reinforcing effect of recovered carbon blacks, the modification of recovered carbon black was performed by high-energy electron bombardment and non-oxidising acid. The specific surface area of the pyrolytic carbon blacks increased after high-energy electron bombardment. The ash content of the pyrolytic carbon black was reduced from 22.5% to 8.4% after rinsing with hydrochloric acid, and the tensile stress at 300% was increased by about 2.2 MPa.

The aim of the present meta-analysis was to systematically examine the literature and to identify of the results of randomized controlled trials (RCTs) comparing the efficacy and safety of regional anesthesia (RA) versus general anesthesia (GA) for percutaneous nephrolithotomy (PCNL). An exhaustive electronic literature search of PubMed, Embase, and Web of science was performed until March 2018. Nine prospective RCTs concluding 858 patients comparing the use of RA to GA for PCNL were included. Combined results demonstrated that PCNL under RA could reduce operative time (mean difference [MD] -6.20; 95% CI -10.39 to -2.01), hospital stay (MD -0.59; 95% CI -0.74 to -0.45), visual analgesic score on the first and third postoperative day (MD -2.62, 95% CI -3.04 to -2.19 and MD -0.38; 95% CI -0.58 to -0.18) , analgesic requirements (MD -36.84; 95% CI -55.23 to -18.45), and nausea and/or vomiting (relative risk [RR] 0.28; 95% CI 0.13-0.61). There were no significant differences between RA and GA groups in terms of stone-free rate, blood transfusion, and postoperative fever rate. The results of subgroup analysis were basically consistent with the overall findings. Current evidence suggests that RA is an available and safe option in carefully evaluated and selected patients.

AbstractThe surface activity of carbon black (CB) is an important factor affecting the reinforcement of rubber. The quantitative determination of the surface activity (surface free energy) of CB is of great significance. A simplified formula is obtained to determine the free energy of CB surface through theoretical analysis and mathematical derivation. The surface free energy for four kinds of industrial CBs were measured by inverse gas chromatography, and the influential factors were studied. The results showed that the aging time of the chromatographic column plays an important role in accurate measurement of the surface free energy of CB, in comparison with the influences from the inlet pressure and carrier gas flow rate of the chromatographic column filled with CB. Several kinds of industrial CB were treated at high temperature, and the surface free energy of CB had a significant increase. With the increase of surface free energy, the maximum torque was decreased significantly, the elongation at break tended to increase, the heat generation of vulcanizates was increased, and the wear resistance was decreased.