Use of macro plastic fibres to reinforce concrete has attracted widespread attention from both scientists and construction industry due to the multiple sustainability benefits they offer, compared to steel fibres and steel reinforcing mesh. This paper critically reviews the current state of knowledge and technology of using macro plastic fibres to reinforce concrete. Detailed review on the various preparation techniques and the resulting properties of macro plastic fibres are presented and the effects of macro plastic fibres on the fresh and hardened concrete properties are discussed in this paper. The effect of macro plastic fibres on workability, plastic shrinkage, compressive strength, splitting tensile strength, flexural strength, post-crack performance and dry shrinkage is discussed in this paper. Pull-out behaviour and degradation behaviour of the fibre in the concrete are also reviewed. Finally, some applications of the plastic fibre reinforced concrete are discussed.
Efficient technology and applications for recycled polymer waste has become increasingly important to decrease environmental contamination and to conserve nonrenewable fossil fuels. Mechanical recycling is the most widely practiced in Australia, since it is relatively easy and economic; and moreover, infrastructure for collection and reprocessing has been well established. In order to improve quality of end products of recycled plastics, various workable reprocessing techniques in the second stage of mechanical recycling have been developed and widely applied in the recycling industry. This article critically reviews the current reprocessing techniques of recycled polyolefins. Reprocessing recycled polyolefins is always accompanied with degradation, crystallization, and consequent processability problems, which result from molecular chain scission, branching, and crosslinking. The present state of knowledge and technology of various reprocessing techniques, including melt blending, filler reinforcement and mechanochemistry, is then described and evaluated systematically. Each reprocessing technique presents its own individual advantages and special applications. POLYM. ENG. SCI., 55:2899-2909, 2015
Type-II glass-like carbon is a widely used material with a unique combination of properties including low density, high strength, extreme impermeability to gas and liquid and resistance to chemical corrosion. It can be considered as a carbon-based nanoarchitectured material, consisting of a disordered multilayer graphene matrix encasing numerous randomly distributed nanosized fullerene-like spheroids. Here we show that under both hydrostatic compression and triaxial deformation, this high-strength material is highly compressible and exhibits a superelastic ability to recover from large strains. Under hydrostatic compression, bulk, shear and Young's moduli decrease anomalously with pressure, reaching minima around 1-2 GPa, where Poisson's ratio approaches zero, and then revert to normal behaviour with positive pressure dependences. Controlling the concentration, size and shape of fullerene-like spheroids with tailored topological connectivity to graphene layers is expected to yield exceptional and tunable mechanical properties, similar to mechanical metamaterials, with potentially wide applications.
BackgroundTo determine the epidemiology and risk factors for nosocomial infection (NI) in the Respiratory Intensive Care Unit (RICU) of a teaching hospital in Northwest China.MethodsAn observational, prospective surveillance was conducted in the RICU from 2013 to 2015. The overall infection rate, distribution of infection sites, device-associated infections and pathogen in the RICU were investigated. Then, the logistic regression analysis was used to test the risk factors for RICU infection.ResultsIn this study, 102 out of 1347 patients experienced NI. Among them, 87 were device-associated infection. The overall prevalence of NI was 7.57% with varied rates from 7.19 to 7.73% over the 3 years. The lower respiratory tract (43.1%), urinary tract (26.5%) and bloodstream (20.6%) infections accounted for the majority of infections. The device-associated infection rates of urinary catheter, central catheter and ventilator were 9.8, 7.4 and 7.4 per 1000 days, respectively.The most frequently isolated pathogens were Staphylococcus aureus (20.9%), Klebsiella pneumoniae (16.4%) and Pseudomonas aeruginosa (10.7%). Multivariate analysis showed that the categories D or E of Average Severity of Illness Score (ASIS), length of stay (10–30, 30–60, ≥60 days), immunosuppressive therapy and ventilator use are the independent risk factors for RICU infection with an adjusted odds ratio (OR) of 1.65 (95% CI: 1.15~2.37), 5.22 (95% CI: 2.63~10.38)), 2.32 (95% CI: 1.19~4.65), 8.93 (95% CI: 3.17~21.23), 31.25 (95% CI: 11.80~63.65)) and 2.70 (95% CI: 1.33~5.35), respectively.ConclusionA relatively low and stable rate of NI was observed in our RICU through year 2013–2015. The ASIS-D、E, stay ≥10 days, immunosuppressive therapy and ventilator use are the independent risk factors for RICU infection.
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