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).
Non-Wood Fiber as an Alternative to Wood Fiber in Chinas Pulp and Paper Industry
Summary The pulp and paper industry in China has been growing rapidly as the nation's population and economy have grown. As a result, there has been a huge demand for pulp and paper raw materials. China has a long tradition for using non-wood raw materials for pulp and paper due to its limited forest resources and rich supply of agricultural residues and non-wood plants. Agricultural residues, such as rice straw and wheat straw, are traditional raw materials for China's paper industry. Massive plantation of bamboo provides an increasingly important source of raw material for pulp and paper. Problems with non-wood fiber include collection and transportation, storage and handling, washing, bleaching, papermaking, and chemical recovery. Small mills, primary users of non-wood fiber, are typically deficient in pollution control and subject to government closure. This paper reviews non-wood fibers commonly used in China's pulp and paper industry. By increased knowledge of use of non-wood fibers, wood suppliers can plan for access to the growing Chinese market.
Thermal incompatibility analysis of metal-ceramic systems based on flexural displacement data.
The feasibility of simple tests or analytical methods for prediction of residual stress states in metal-ceramic (MC) prostheses has not been demonstrated. Biomaterial metal-ceramic strips have been proposed to provide sensitive measures of transient and residual stress states through the measurement of midpoint deflection after cooling from the ceramic sintering temperature. The objective of this study was to apply the elastic-viscoelastic analogy to calculate transient and residual midpoint deflections in MC biomaterial strips and to compare these values with deflections measured with a beam-bending viscometer (BBV). Calculations and measurements were made for five MC systems that were found from a clinical study to be "thermally compatible" systems. Metal strips, 64 mm in length, 3 mm wide, and either 0.5 mm, 1.0 mm, or 2.0 mm in thickness, were veneered with four 0.25-mm thick layers of opaque porcelain. Midpoint deflection of the MC strips (ceramic oriented in the posterior position) was measured during cooling from an initial temperature of 700 degrees C. In general, the directions of the measured residual deflections did not agree with the "textbook" convention that negative deflections are associated with positive thermal contraction mismatch (alpha(M) - alpha(c) > 0) regardless of metal thickness. For a metal thickness of 0.5 mm, the residual midpoint deflection for all thermal contraction mismatch cases, except one, was positive (upward deflection) whereas the residual midpoint deflections were all negative when the metal thickness was increased to 1 or 2 mm, independent of the thermal contraction mismatch. The best agreement between calculated and measured values of residual midpoint deflection (+16 microns vs. +14 +/- 2.3 microns, respectively was obtained for MC biomaterial strips with a Ni-Cr alloy (0.5 mm thick) while the largest difference (+346 microns vs. +61 +/- 43.8 microns) was obtained for MC bimaterial strips with a Au-Pd allow (0.5 mm thick). In all but one case, changes in deflection direction as a function of metal thickness were correctly predicted by the viscoelastic analysis. The results of this study indicate that a viscoelastic model is useful for estimating thermal compatibility conditions of MC systems.