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PSE322 Questions and Correct Answers/ Latest
Update / Already Graded
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?
Ans: 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
Ans: Phenolpropane
What is the name of the hollow space in the middle of a hardwood fiber or in a
softwood tracheid?
Ans: Lumen
Before bleaching, kraft-pulped fibers have what color?
Ans: 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
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c.Highest concentration of lignin
d.Adjacent to the middle lamella
Ans: 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
Ans: 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
Ans: b.Fan pulp and pressure screen
Accepts from which bank of hydrocyclones goes forward to the next unit operation
(pressure screen)?
Ans: Primary
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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
Ans: 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
Ans: 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.
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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.
Ans: 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
Ans: 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
PSE322 Questions and Correct Answers/ Latest
Update / Already Graded
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?
Ans: 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
Ans: Phenolpropane
What is the name of the hollow space in the middle of a hardwood fiber or in a
softwood tracheid?
Ans: Lumen
Before bleaching, kraft-pulped fibers have what color?
Ans: 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
, 2 | Page
c.Highest concentration of lignin
d.Adjacent to the middle lamella
Ans: 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
Ans: 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
Ans: b.Fan pulp and pressure screen
Accepts from which bank of hydrocyclones goes forward to the next unit operation
(pressure screen)?
Ans: Primary
, 3 | Page
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
Ans: 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
Ans: 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.
, 4 | Page
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.
Ans: 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
Ans: 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
