In the first part of the study, dyed polyester fabric was treated with a dielectric barrier discharge (DBD) plasma at 1 W/cm2 for 15, 30, 60 and 90 s. The wicking height, tensile strength and color of the control and plasma treated fabrics were measured. Results show that the fabric capillary increases with plasma treatment time up to 90 s. However, plasma treatment time longer than 60 s caused an obvious color change and decrease in tensile strength of fabric. Plasma contact time should be such that plasma can improve the hydrophilicity of the fabric and adversely affect the properties of the fabric as little as possible. Thus, the suitable plasma contact time should be less than 60 s. Based on these results, in the second part of the study, three different time levels (15, 20 and 30 s) were selected for plasma pretreatment of this fabric. The plasma-treated fabric was then padded with the flame retardant (FR) (CETAFLAM PDP 30), dried and finally cured at 190 °C for 120 s. The limited oxygen index (LOI) of FR fabrics and the vertical fire characteristics of FR fabric after being washed 5 times also were measured. Comparison of these results with those of FR fabrics without plasma pretreatment shows that plasma pretreatment improves the fabric’s flame retardancy and FR durability. Moreover, it also reduces the heat shrinkage of PET fabric due to high temperature curing. The scanning electron microscopy (SEM) images of the fabric after plasma treatment and FR treatment and the energy-dispersive spectroscopy (EDS) spectrum of the fabric are consistent with the above results.

An experimental method is proposed for evaluating the creep crack growth (CCG) rate by using small punch (SP) creep test specimens with an elliptic surface crack at the center of the specimen. Expressions for high-temperature crack tip fracture parameter Ct were developed in full creep regime, from small-scale creep to extensive creep condition, for the crack model employed in the experiments. The Ct equation was derived by using the existing solution of the stress intensity factor K and the J-integral. A series of cracked SP creep tests were conducted for various levels of constant loads and testing periods. An SP specimen with a sharp notch was used instead of a precracked specimen. Preliminary results showed the feasibility of the suggested method for evaluating the CCG properties of materials. The CCG rate obtained from the precracked SP tests was significantly lower than that obtained from conventional compact tension specimens.

This paper presents a hydrometallurgical treatment of electric arc furnace (EAF) dust which was taken from a Vietnamese steelmaking plant to obtain zinc oxide (ZnO) nanoparticles by using aqueous ammoniac carbonate solution as a leaching agent. Characterization of the EAF dust was conducted by XRD technique, SEM observation and manual wet chemical analysis. The results showed that total zinc (Zn) of the dust was 42.69 wt.% and existed mainly in the forms of zincite - ZnO, simonkolleite - Zn5(OH)8Cl2H2O, and franklinite - ZnFe2O4. The leached condition, in which the ammoniac carbonate concentration was 300 g/l and the time was 90 minutes, was found to provide the highest leaching efficiency as 85.29 % when the temperature was fixed at 60?C and the ratio of solid/liquid was 1/6. After some steps of the subsequent treatment, the ZnO nanoparticles with the purity of 99.5 % and the size of 100 nm were obtained from thermal decomposition of zinc carbonate hydroxide - Zn5(CO3)2(OH)6.