Estimation of coal particle size distribution by image segmentation

Several industrial coal processes are largely determined by the distribution of particle sizes in their feed.Currently these parameters are measured by manual sampling,which is time consuming and cannot provide real time feedback for automatic control purposes.In this paper,an approach using image segmentation on images of overlapped coal particles is described.The estimation of the particle size distribution by number is also described.The particle overlap problem was solved using image enhancement algorithms that converted those image parts representing material in lower layers to black.Exponential high-pass filter(EHPF) algorithms were used to remove the texture from particles on the surface.Finally,the edges of the surface particles were identified by morphological edge detection.These algorithms are described in detail as is the method of extracting the coal particle size.Tests indicate that using more coal images gives a higher accuracy estimate.The positive absolute error of 50 random tests was consistently less than 2.5% and the errors were reduced as the size of the fraction increased.

Green-synthesized gold nanoparticles from Plumeria alba flower extract to augment catalytic degradation of organic dyes and inhibit bacterial growth

Bio-inspired eco-friendly gold nanoparticles were synthesized by a green method using aqueous Plume- ria alba flower extract （PAFE）. The use of 1% and 5% concentrations of PAFE resulted in two different sizes of P. alba gold nanoparticles, PAGNPsl and PAGNPs2, with surface plasmon resonance （SPR） peaks at 552 and 536 nm, respectively. Size-controlled formation of gold nanoparticles was indicated by the SPR shift observed with increasing concentration of PAFE. The accurate size and morphology of PAGNPs I and PAGNPs2 were determined by transmission electron microscope （TEM） analysis is found to be 28 ＋ 5.6 and 15.6 4-3.4 nm, respectively, and those are spherical in shape. The antibacterial activity of PAGNPsl and PAGNPs2 was tested against Escherichia coil; the small-sized PAGNPs2 exhibited better antibacterial activity with a 16-mm zone of inhibition at a concentration of 400 txg/mL. Furthermore, the catalytic activity of PAGNPsl and PAGNPs2 was analyzed on six hazardous dyes; PAGNPs2 exhibited more pro- nounced catalytic activity than PAGNPsl. Among all of the dyes, 4-nitrophenol was most rapidly degraded to 4-aminophenol by PAGNPs2 within 5 min. The mechanism of catalysis in the presence of PAGNPsl and PAGNPs2 can be described as an electron transfer process from donor NaBH4 to an acceptor. The facile green synthesis of such eco-friendly nanoparticles in bulk suggests this method has potential industrial applications.