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Q1— Section header —
1.5\in the ANSWER BOOK. Correct the statement if it is FALSE.
1.5Linerboard has at least two plies and is usually made on a Yankee with 100% virgin pulp. Pressing can be considered an extension of the water removal process. Two sidedness on a sheet is caused by a difference in fibre composition.
Q2— Section header —
2.10\ the ANSWER BOOK.
2.10Caliper Deculator Biocides Defalking Filler Calendering Printability Evaporation Net specific energy
Q3— Section header —
3.1The paper machine you work at produces uncoated wood free paper.
3.1.4What does the term uncoated wood free paper mean? Give an example of this type of paper What is furnish composed of Give reasons for your selection of
3.2A recovered fibre plant uses flotation cells in its process. Explain how the ink is removed from the waste paper in the flotation cells. (2\ [10]10
Q4— Section header —
4.1Give a detailed discussion on the design philosophy of the approach flow system. (5\
4.2Explain what adjustments you would make in order to correct variations in the cross machine basis mass profile in an air cushioned headbox. (5\
4.3The various factors involved in sheet formation in air padded headboxes are: jet to wire ratio, jet ang le, L/b ratio, and forming board position. Describe how each factor affects formation and other properties.
Q5— Section header —
5.1List FOUR problems caused by slime on a paper machine. (4\
5.2Propose a strategy to control slime on your paper machine. (3\
5.3Most modern paper mills have changed from acid sizing to neutral or alkaline sizing. Give FOUR reasons why they have opted for this change. (4\
5.4Describe the role of cationic starch in ASA emulsification systems. (3\ [14] 1102211414
Q6— Section header —
6.1Significant savings in energy costs can be made if the amount of water removed at the press section is increased. Explain how the following factors influence water removal in the press section:
6.1.3Nip impulse Basis mass Temperature (3\ (2\ (1\
6.2The effective removal of condensate by the use of siphons is crucial for efficient dryer performance. Describe THREE types of siphons which are commonly used in dryer cylinders and explain their principles of operation.
Q7— Section header —
7.1List the factors that influence starch pick up at the size press (10\
7.2ame TWO methods of cleaning machine fabrics. (2\ [12]12
Q8— Section header —
8.1How does refining affect the following paper properties:
8.1.6Burst strength Ring crush Opacity Tensile Brightness Formation (6 1\
8.2The appearance or optical properties of paper are of considerable importance to the end user. Explain the factors that influence the following paper properties:
8.2.3Opacity Brightness Gloss (3 2\ (6\ [12] TOTAL SECTION B:12