PSE322 EXAM QUESTIONS AND ANSWERS
What type of costs related to the manufacture of paper does not change when the
amount of product being made per unit time in a paper mill changes? - Answers :Fixed
Costs
Which of the following is NOT classified as an extractive component of wood?
Phenolpropane
a.Phenolpropane
b.Rosin
c.Triglyceride fat
d.Pinene - Answers :Phenolpropane
What is the name of the hollow space in the middle of a hardwood fiber or in a softwood
tracheid? - Answers :Lumen
Before bleaching, kraft-pulped fibers have what color? - Answers :Brown
Which of the following is true regarding the S2 sublayer within wood fibers often used
for paper pulp?
a.Microfibril angle at right angles to the fiber axis
b.The most important layer, by mass
c.Highest concentration of lignin
d.Adjacent to the middle lamella - Answers :b.The most important layer, by mass
What often becomes ribbon-like in the course of pulping, refining, and formation into
paper?
a.Parenchyma cells
b.Precipitated hemicellulose
c.Cellulosic fines
d.Fibers - Answers :d.Fibers
Which two unit operations in the paper machine system typically involve the highest
level of hydrodynamic shear stress?
a.Flow distributor and rectifier rolls
b.Fan pulp and pressure screen
c.Headbox slice and hydrofoils
d.Dynamic drainage jar and sheet mold - Answers :b.Fan pulp and pressure screen
Accepts from which bank of hydrocyclones goes forward to the next unit operation
(pressure screen)? - Answers :Primary
What helps to prevent formation of a fiber mat within the pressure screen system?
,a.Bubbles of air
b.Action of the rotor
c.Wiper blades
d.Mechanical vibrations - Answers :b.Action of the rotor
What usually provides the vacuum for a typical low-vacuum box on a Fourdrinier paper
machine?
a.A vacuum pump
b.The weight of water flowing down a tube to a seal tank
c.Evaporation induced by convective currents of air
d.A fan that accelerates air and water from the box - Answers :b.The weight of water
flowing down a tube to a seal tank
What happens to the capillary vacuum effect (negative pressure) within the meniscus at
a crossing between adjacent fibers in paper during the evaporative drying process?
a. The negative pressure is reduced in the course of drying because of steadily
increasing temperature.
b. The capillary forces remain constant, since they depend only on the nature of the
fluid and the air, as long as the contact angle with the fiber surface is zero.
c. The attractive force due to the meniscus becomes stronger as the distance between
the fibers decreases because of evaporation.
d. The capillary forces become repulsive, allowing the paper to expand and achieve the
bulk that is desired in such grades as paper towels. - Answers :c. The attractive force
due to the meniscus becomes stronger as the distance between the fibers decreases
because of evaporation.
Where does the main suction take place as the forming fabric passes over a hydrofoil?
a. At the leading edge due to a doctoring effect, in which water is being removed from
the bottom side of the forming fabric on a Fourdrinier paper machine
b. On the trailing 2/3 of the surface, where the forming fabric may have to change its
path slightly, with the help of vacuum, to maintain contact with the foil surface
c. On the leading edge, where the foil is pressing most strongly against the hydrofoil
surface, leading to a maximization of the venturi effect
d. At the trailing edge, where there is an abrupt break-off of the suction action, often
leading to "stock jump", which is especially apparent under stroboscopic illumination -
Answers :b. On the trailing 2/3 of the surface, where the forming fabric may have to
change its path slightly, with the help of vacuum, to maintain contact with the foil surface
What location associated with a steam-heated dryer can typically has the highest
temperature?
a. Within condensate at the inner surface of the can
, b. Within the steel shell itself, due to its heat capacity
c. In the paper, due to its contact with multiple dryer cans
d. On the outer surface, due to the flow of heat outwards - Answers :b. Within the steel
shell itself, due to its heat capacity
What is usually used at the wet end to cut the edge of the wet web to achieve the
desired width of paper at the reel of the paper machine?
a. Laser cutters
b. Slitter knives
c. Trim squirts
d. Doctor blades - Answers :c. Trim squirts
Which is an accurate description of hydrogen bonds within liquid water?
a. Connecting and disconnecting in femtoseconds
b. Stronger than covalent bonds
c. Same as ice, but with occasional defects
d. Forming time-stable clusters - Answers :a. Connecting and disconnecting in
femtoseconds
What is a brief way to express "the negative logarithm, base ten, of the hydrogen ion
concentration? - Answers :pH
Scale is able to form in an industrial process only if the following quantity is exceeded
for a certain inorganic compound.
a. Precipitation point
b. Maximum hardness
c. Critical scaling concentration
d. Solubility product - Answers :d. Solubility product
What quantity equals the electrical potential at the "slip plane" near to a surface in
contact with aqueous solution?
a. Zeta potential
b. Anionic demand
c. Electrical conductivity
d. Cationic demand - Answers :a. Zeta potential
Which of the following situations is LEAST desirable from the standpoint of running a
paper machine?
a. Slightly negative cationic demand at the headbox due to alum addition
b. Charge demand swinging back and forth between positive and negative
c. High constant value of cationic demand (net negative charge)
What type of costs related to the manufacture of paper does not change when the
amount of product being made per unit time in a paper mill changes? - Answers :Fixed
Costs
Which of the following is NOT classified as an extractive component of wood?
Phenolpropane
a.Phenolpropane
b.Rosin
c.Triglyceride fat
d.Pinene - Answers :Phenolpropane
What is the name of the hollow space in the middle of a hardwood fiber or in a softwood
tracheid? - Answers :Lumen
Before bleaching, kraft-pulped fibers have what color? - Answers :Brown
Which of the following is true regarding the S2 sublayer within wood fibers often used
for paper pulp?
a.Microfibril angle at right angles to the fiber axis
b.The most important layer, by mass
c.Highest concentration of lignin
d.Adjacent to the middle lamella - Answers :b.The most important layer, by mass
What often becomes ribbon-like in the course of pulping, refining, and formation into
paper?
a.Parenchyma cells
b.Precipitated hemicellulose
c.Cellulosic fines
d.Fibers - Answers :d.Fibers
Which two unit operations in the paper machine system typically involve the highest
level of hydrodynamic shear stress?
a.Flow distributor and rectifier rolls
b.Fan pulp and pressure screen
c.Headbox slice and hydrofoils
d.Dynamic drainage jar and sheet mold - Answers :b.Fan pulp and pressure screen
Accepts from which bank of hydrocyclones goes forward to the next unit operation
(pressure screen)? - Answers :Primary
What helps to prevent formation of a fiber mat within the pressure screen system?
,a.Bubbles of air
b.Action of the rotor
c.Wiper blades
d.Mechanical vibrations - Answers :b.Action of the rotor
What usually provides the vacuum for a typical low-vacuum box on a Fourdrinier paper
machine?
a.A vacuum pump
b.The weight of water flowing down a tube to a seal tank
c.Evaporation induced by convective currents of air
d.A fan that accelerates air and water from the box - Answers :b.The weight of water
flowing down a tube to a seal tank
What happens to the capillary vacuum effect (negative pressure) within the meniscus at
a crossing between adjacent fibers in paper during the evaporative drying process?
a. The negative pressure is reduced in the course of drying because of steadily
increasing temperature.
b. The capillary forces remain constant, since they depend only on the nature of the
fluid and the air, as long as the contact angle with the fiber surface is zero.
c. The attractive force due to the meniscus becomes stronger as the distance between
the fibers decreases because of evaporation.
d. The capillary forces become repulsive, allowing the paper to expand and achieve the
bulk that is desired in such grades as paper towels. - Answers :c. The attractive force
due to the meniscus becomes stronger as the distance between the fibers decreases
because of evaporation.
Where does the main suction take place as the forming fabric passes over a hydrofoil?
a. At the leading edge due to a doctoring effect, in which water is being removed from
the bottom side of the forming fabric on a Fourdrinier paper machine
b. On the trailing 2/3 of the surface, where the forming fabric may have to change its
path slightly, with the help of vacuum, to maintain contact with the foil surface
c. On the leading edge, where the foil is pressing most strongly against the hydrofoil
surface, leading to a maximization of the venturi effect
d. At the trailing edge, where there is an abrupt break-off of the suction action, often
leading to "stock jump", which is especially apparent under stroboscopic illumination -
Answers :b. On the trailing 2/3 of the surface, where the forming fabric may have to
change its path slightly, with the help of vacuum, to maintain contact with the foil surface
What location associated with a steam-heated dryer can typically has the highest
temperature?
a. Within condensate at the inner surface of the can
, b. Within the steel shell itself, due to its heat capacity
c. In the paper, due to its contact with multiple dryer cans
d. On the outer surface, due to the flow of heat outwards - Answers :b. Within the steel
shell itself, due to its heat capacity
What is usually used at the wet end to cut the edge of the wet web to achieve the
desired width of paper at the reel of the paper machine?
a. Laser cutters
b. Slitter knives
c. Trim squirts
d. Doctor blades - Answers :c. Trim squirts
Which is an accurate description of hydrogen bonds within liquid water?
a. Connecting and disconnecting in femtoseconds
b. Stronger than covalent bonds
c. Same as ice, but with occasional defects
d. Forming time-stable clusters - Answers :a. Connecting and disconnecting in
femtoseconds
What is a brief way to express "the negative logarithm, base ten, of the hydrogen ion
concentration? - Answers :pH
Scale is able to form in an industrial process only if the following quantity is exceeded
for a certain inorganic compound.
a. Precipitation point
b. Maximum hardness
c. Critical scaling concentration
d. Solubility product - Answers :d. Solubility product
What quantity equals the electrical potential at the "slip plane" near to a surface in
contact with aqueous solution?
a. Zeta potential
b. Anionic demand
c. Electrical conductivity
d. Cationic demand - Answers :a. Zeta potential
Which of the following situations is LEAST desirable from the standpoint of running a
paper machine?
a. Slightly negative cationic demand at the headbox due to alum addition
b. Charge demand swinging back and forth between positive and negative
c. High constant value of cationic demand (net negative charge)
