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Fillers such as Clay are added to the paper making process to improve _____A______ and/or ______B______, and/or _____C_____.  Nevertheless, fillers, unfortunately, also reduce _____D_____.    In the text box below, write in the appropriate missing words (answers) for A, B, C, and D.

At high speed paper machines you sometimes can observe an effect called “rimming.” A) Where on the paper machine does this happen? B) What (negative) effect does it have? C) How can the negative effect of rimming be prevented or minimized?  

Shown below is a tapered flow spreader on a paper machine. A) What is the function of a flow spreader? B) How is the pressure of slurry (and hence even distribution of pulp slurry through the different inlets to the head box and uniform basis weight across the machine width) controlled? C) Do we use such a tapered flow spreader in a modern hydraulic head box?

What is latency ? In which pulping process do you observe latency and why? How would you address/remove latency?

Over the years there have been some attempts to improve the Kraft process. Please name one of the “newer“ developments and explain what property/variable they are trying to improve.

Wood Chip quality is very important for pulp quality for both mechanical and chemical pulping. Some chip variables include: bark content, extractive (pitch) content, uniform thickness, chip age, rotten wood content, sand content. a) Please pick one variable you think is the most important for mechanical pulping and one variable that is the most important for chemical pulping and explain why you picked this one and how you would try to control it. b) From a mass transfer perspective what are some of the basic  mechanisms that play a role during Kraft pulping of wood chips.  

Paper made from mechanical pulp generally has a lower tensile strength than paper made from chemical pulps. Please explain why that is, I am looking for at least two reasons. What kind of paper grade or paper product (give one example) are mechanical pulps most suited for?     

Please describe the operation of a wet electrostatic precipitator? What function does the water have in these systems? 

Why can an aerated lagoon be designed to be 25 or more feet deep, while a natural lagoon cannot be deeper than 3 or 4 feet?

Define the terms BOD5 and COD. Indicate what they measure and explain in general terms how the tests are performed.