Effect of hydrodynamic desulphurisation of low parameters on the oxidative rank coal

In this paper, the desulphurisation of high sulphur low-rank coal is proposed as a raw material for pulverised coal injection technology. Therefore, the influence of oxidant linear velocity and the size of the coal grain was investigated in a fluidised bed. The hydrodynamic parameters of the fluidised bed including： porosity, Sherwood criterion （diffusion Nusselt number）, and mass transfer coefficient （external surface） were calculated. Furthermore, the study examined the effects of intensity and efficiency on the desulphurised coal properties; organic matter, ash, and volatile matter contents. The key changes during the conversion of pyritic sulphur and coal organic matter were subsequently examined. The results showed that the sulphur content （St^d 3.16 wt%） of the low-rank coal, was transformed to （St^d 〈 1.5 wt%） after desulfurization. Other enhanced properties were： V^daf ≤ 38.0 wt%; A^d 〈 10.0 wt%, now suitable for pulverised coal injection technology.

Antilisterial action of PLA films with ferulic acid as affected by the method of incorporation

Previous studies demonstrated that polylactic acid (PLA) films with ferulic acid (F) obtained by melt blending did not release the active compound to exert effective antibacterial action. To solve this problem, different strategies to promote the active properties of PLA-F materials have been studied: film processing by casting with F up to 10% w/w, surface loading of thermoprocessed films with F, by adsorption or pulverisation with F solutions, and electrospinning of PLA-F solutions, using different solvent systems, to obtain nanostructured mats. The materials obtained were characterised by their morphological properties and antilisterial activity. F crystallised inside cast films and on the surface loaded PLA films. Electrospun materials exhibited different morphology, depending on the solvent system of the initial solution;fibre mats were obtained with ethyl acetate-DMSO mixtures, whereas bead structures were mainly formed with glacial acetic acid with or without ethyl acetate. No antilisterial activity was observed in cast films regardless of the F concentration, whereas surface loaded films by adsorption or pulverisation inhibited the listeria growth by about 4 Log (CFU/mL). Electrospun materials only inhibited bacterial growth (3 Log CFU) when these were fibre-structured. Therefore, active films of PLA with F could be only obtained when the active was surface anchored or encapsulated in thin fibre mats, with high surface to volume ratio. In this way, the release of the active compound is promoted, avoiding the problem of its limited internal diffusion through the PLA matrix.

Seismic retrofitting of severely damaged RC connections made with recycled concrete using CFRP sheets

An experimental and numerical program is carried out in this research to investigate the influence of CFRP sheets on the cyclic behavior of unconfined connections made with recycled concrete.Cement is partially replaced by silica fume,iron flling and pulverised fuel ash using two different percentages:15%and 20%.Each specimen is partially loaded at the first stage and then specimens are repaired using CFRP sheets.The repaired specimens are then laterally loaded until failure.In addition,a finite element model is built in ABAQUS and verfed using the experimental results.The experimental results have shown that the repaired specimens have regained almost double the capacity of the un-repaired specimens and hence the adopted repair configuration is recommended for retroftting seismically vulnerable RC connections.Increasing cement replacement percentage by silica fume,fuel ash or iron flling from 15%to 20%has reduced joint carrying capacity and weakened the joint.It is recommended using 15%pulverised fuel ash or silica fume as cement partial replacement to enhance the strength and ultimate drift of beam-column joints under cyclic loading.Iron filling concrete is also recommended but the enhancement is relatively less than that found with pulverised fuel ash concrete and silica fume concrete.