Sökning: "Lennart Salmén"

Visar resultat 1 - 5 av 6 avhandlingar innehållade orden Lennart Salmén.

1. 1. The effect of environment on refining efficiency of kraft pulps

   Författare :Marie Bäckström; Monica Ek; Lennart Salmén; Leif Robertsen; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Chemical Engineering; Kemiteknik;

   Sammanfattning : Although the pulp and paper mill processes have been operational for long time there is still a need to understand the unit operations in paper making and how they interact with the ingoing pulp material. This is crucial in order to fully utilize the potential of the wood as well as of the unit operations. LÄS MER

3. 2. Cellulose-water interaction: a spectroscopic study

   Författare :Erik L Lindh; István Furó; Lennart Salmén; Lisbeth G Thygesen; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; cellulose; water; hydrogen exchange; deuterium; NMR spectroscopy; FT-IR spectroscopy; Kemi; Chemistry;

   Sammanfattning : The human society of today has a significantly negative impact on the environment and needs to change its way of living towards a more sustainable path if to continue to live on a healthy planet. One path is believed to be an increased usage of naturally degradable and renewable raw materials and, therefore, attention has been focused on the highly abundant biopolymer cellulose. LÄS MER

4. 3. Transverse anisotropy in softwoods : Modelling and experiments

   Författare :Carl S. Modén; Lars Berglund; Lennart Salmén; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Softwood; Cellular solid; Anisotropy; Deformation mechanisms; Materials science; Teknisk materialvetenskap;

   Sammanfattning : Transverse anisotropy is an important phenomenon of practical and scientific interest. Although the presence of ray tissue explains the high radial modulus in many hardwoods, experimental data in the literature shows that this is not the case for pine. LÄS MER

5. 4. A way of reducing the energy demand in TMP by shear/compression deformation

   Författare :Silvia Viforr; Lars Wågberg; Lennart Salmén; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; shear; compression; pulses; wood chips; coarse fibre; mechanical pulping; wood cells; Cellulose and paper engineering; Cellulosa- och pappersteknik;

   Sammanfattning : One of the major cost factors in mechanical pulp production is the electrical energy input. Much of the research in this field has therefore been devoted to an understanding of the mechanisms in the refining process and, consequently, to find ways of reducing the electrical energy consumption. LÄS MER

7. 5. Influence of acid hydrogen peroxide treatment on refining energy and TMP properties

   Författare :Karin Walter; Per Engstrand; Magnus Paulsson; Lennart Salmén; Mittuniversitetet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TMP; Black Spruce; Energy reduction; Hydrogen peroxide; Ferrous sulphate; Refining; Inter-stage treatment; Pulp and paper properties; Fenton´s reagent; Bleaching; Sodium dithionite; Brightness; Metals; Fibre dimensions; Cross-sectional dimensions; Chemical composition; Cellulose and paper engineering; Cellulosa- och pappersteknik;

   Sammanfattning : The potential of using acid hydrogen peroxide under Fenton conditions to lower the electrical energy consumed during the production of Black spruce (Picea mariana) thermomechanical pulp (TMP) was investigated. The chemical system, which consisted of ferrous sulphate, hydrogen peroxide and optionally an enhancer (3,4-dimethoxybenzyl alcohol, ethylenediaminetetraacetic acid or oxalic acid/sodium oxalate), was evaluated as an inter-stage treatment where the primary refiner was used as a mixer. LÄS MER