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.
Rubik's for cryptographers
Hard mathematical problems are at the core of security arguments in cryptography. In this paper, we study mathematical generalizations of the famous Rubik’s cube puzzle, namely the factorization, representation and balance problems in non-Abelian groups. These problems arise naturally when describing the security of Cayley hash functions, a class of cryptographic hash functions with very interesting properties. The factorization problem is also strongly related to a famous long-standing conjecture of Babai, at the intersection of group theory and graph theory. A constructive proof of Babai’s conjecture would make all Cayley hash functions insecure, but on the other hand it would have many positive applications in graph theory and computer science. In this paper, we classify existing attacks against Cayley hash functions and we review known results on Babai’s conjecture. Despite recent cryptanalytic progress on particular instances, we show that the factorization, representation and balance problems presumably remain good sources of cryptographic hard problems. Our study demonstrates that Cayley hash functions deserve further interest by the cryptography community.