NSSC pulp from planted populus and hardwood sawdust for flutting production
This research was performed with the goal of using neutral sulfite semi chemical pulp (NSSC) from populous instead of all or part of MWPI’s NSSC pulp for producing fluting paper. Firstly, NSSC pulp was prepared from populous species and hardwood sawdust under the mill’s cooking conditions. Then, the two mentioned pulp samples were replaced with the mill’s NSSC pulp in a variety of mixing ratios. Next, handsheets with 120 g/m2 were produced of mixed pulps and the properties were measured. The results showed that both raw materials could supply the pulp properties in acceptable way in comparison with control pulp (NSSC pulp of Mazandaran mill).
THE EFFECT OF SURFACTANTS APPLICATION ON SODA PULPING OF WHEAT STRAW
This paper details the effects of two non-ionic surfactants, ELA-7 and PEG 1500, on the soda pulping of wheat straw. The results showed that application of either surfactant improved the pulp yield and decreased the screen rejects. The increase in pulp yield at similar kappa number may be due to higher selectivity of delignification affected by surfactant, which can act as a co-solvent. Addition of ELA-7 to cooking liquor didn’t have significant effect on paper properties. But a significant effect was observed with PEG 1500. In fact, it caused a decrease in burst and tensile index but increased the tear index, probably because of a debonding effect of the surfactant. In addition, application of both surfactants improved brightness for both unbleached and bleached pulp samples.
ROOM- AND HIGH-TEMPERATURE MAGNETIC PROPERTIES OF Sm(CobalFexCu0.088Zr0.025)7.5 (x=0.30) SINTERED MAGNETS
The effect of Fe content on room- and high-temperature magnetic properties of Sm(CobalFexCu0.088Zr0.025)7.5 (x=0-0.30) sintered magnets, prepared by the conventional powder metallurgy method, has been systematically studied. With increasing Fe content, the remanences BT and maximum energy products (BH)max at room temperature gradually increase and reach optimal values of 1.055 T with x=0.27 for BT, and 205 kJ/m3 with x=0.21 for (BH)max, respectively, and then drop sharply with further Fe increase. An excessive addition of Fe (x≥0.24) results in rapid deterioration of permanent magnetic properties due to the formation of a considerable amount of FeCo soft magnetic phase. It was found that the effect of Fe content on high temperature stability is huge. The lower the Fe content, the smaller the temperature coefficient of coercivity. When x=0.07, a temperature coefficient of coercivity of -0.14%/K (293-723 K) can be achieved, as compared with -0.23%/K for x=0.21. BT of 0.725 T, bHc of 517 kA/m, iHc of 764 kA/m, and (BH)max of 95 kJ/m3 at 723 K were obtained, and the B-H demagnetization curve remains a straight line.