Exjobbsförslag från företag

Detta är ett uppsatsförslag hämtat från Nationella Exjobb-poolen. Klicka här för att komma tillbaka till samtliga exjobbsförslag.

Förslaget inkom 2005-06-29

Design of an experimental device to form paper sheets - Making sheets with reproducible defects in fibre orientation

OBS! ANSÖKNINGSTIDEN FÖR DETTA EXJOBB HAR LÖPT UT.
The basic principle of forming paper is the same whether the task is performed in a laboratory or on a full scale production unit: A suspension consisting of essentially water and wood fibres is drained through a permeable surface, called wire, that retains the fibres. The remaining water in the sheet thus obtained is removed by pressing and drying.

The properties of the final paper are to a large degree determined by the distribution of fibres in the sheet. An example of great importance is the structural stability problem referred to as curl, that is when a paper sheet deforms out of its plane and acquires a cylindrical shape. The easiest way to observe this effect is to put a newsprint page on the surface of a table. It is not likely to be perfectly flat.

Curl, and the special type therof referred to as twist, are complex phenomena, but it is clear that they are linked to asymmetries in the fibre distribution across the thickness of the sheet. The development of methods to study phenomena related to the fibre distribution suffers from the lack of test samples exhibiting known and quantifiable defects, which can be used for evaluation.

In order to deal with this complication, STFI-Packforsk proposes a Master¿s thesis project aimed at developing a method to produce laboratory paper sheets exhibiting reproducible defects in the orientation of the fibres, such as e.g. swirls and streaks.

Aim of the project:
¿ Survey of possible ways to generate reproducible fibre orientation defects.
¿ Experimental evaluation of the advantages/limitations of different approaches.
¿ Implementation of the most promising approach by modifying an existing laboratory sheet forming unit (if necessary, construction of a new design).

The thesis should preferably be written in English

  GÅ TILL XJOBB.NU FÖR FULLSTÄNDIG INFO OM DETTA EXJOBB




Informationen om uppsatsförslag är hämtad från Nationella Exjobb-poolen.