Module 2: Physical Properties of Common Agricultural Products Flashcards

1
Q

any substance or moisture or mixture of substances that occupy a volume, and has a mass

A

material

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2
Q

properties of a material

A
  • appearance
  • behavior
  • name
  • structure
  • color
  • order
  • order
  • composition
  • any info about subtance
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3
Q

why is it important to study materials?

A
  • to identify its amount and composition
  • study how it will behave under a set of circumstances
  • characterize, recognize, manage, and utilize materials
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4
Q

market value of rice is significantly affected by what?

A

percentage of head rice grains

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5
Q

what factors influence the degree of damage incurred during grain processing?

A

physical and mechanical properties of the material

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6
Q

density and specific gravity are examples of which property of material?

A

physical characteristics

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7
Q

physical characteristics - enumerate

A
  • size and shape
  • density and specific gravity
  • volume
  • surface area
  • porosity
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8
Q

it deals with the characteristics of light reflected from or transmitted through an object as affected by the diff constituents of the object

A

optical properties

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9
Q

imaging used to observe optical properties

A
  • RGB image
  • near infrared (NIR) imagery
  • normalized difference vegetation index (NDVI)
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10
Q

concerned with the strength or resistance of a particular crop when placed under stress

A

mechanical properties

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11
Q

this determines the type and severity of damage a crop will sustain and therefore dictates how that crop should be handled and processed

A

the resistance of a crop to mechanical stress

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12
Q

describe the movement of heat into or out of a material and how much it can sustain

A

thermal properties

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13
Q

thermal properties - enumerate

A
  • thermal conductivity
  • specific heat
  • emissivity
  • thermal capacity
  • surface conductance
  • transmissivity
  • thermal diffusivity
  • absorptivity
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14
Q

concerned with changes in sound transmitted through the material

A

acoustic properties

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15
Q

changes in acoustic properties may be due _____________ changes in the crop or presence of __________ damage that affect the characteristics of sound waves as they pass through the material

A

physiological; physical

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16
Q

changes in the transmittance of electromagnetic radiation, radio frequency and electrical energy

A

electrical properties

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17
Q

electrical property can be measured as crops undergo changes during _________ (maturation/ripening), go through stress conditions, or as moisture is _________ (induced, removed) from the material

A

maturation; removed

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18
Q

electrical properties

A
  • conductance
  • capacitance
  • dielectric properties
  • reaction to electromagnetic radiation
  • conductivity-ability of seeds to hold a surface charge
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19
Q

physical properties of common grain crops

A
  1. grain dimensions
  2. volume and surface area
  3. density and porosity
  4. angle of friction
  5. angle of repose
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20
Q

what are parameters measured in grain dimensions?

A
  • length
  • width
  • thickness
  • diameter
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21
Q

physical property

basis for machine design, particle separation using sieves and grading

A

grain dimensions

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22
Q

physical property

affect rates of heat and mass transfer of a material

A

volume and surface area

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23
Q

physical property

can be estimated through resemblance to known geometric bodies such as spheres, cylinders, or ellipsoids, or by correlation with major dimensions

A

volume and surface area

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24
Q

physical property

calculation of the dimension of bulk storage facilities and intermediate holding bins of given capacity

A

density and porosity

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25
Q

density and porosity indicates the __________ degree of the grains

A

purity

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26
Q

aside from volume and surface area, which physical propertie/s are also necessary for studies on heat and mass transfer?

A

density and porosity

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27
Q

measures mass per unit volume, where volume includes pore spaces

A

bulk density

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28
Q

bulk density is dependent on

A
  • grain moisture content
  • foreign matter present
  • variety of grain sample
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29
Q

this is measured using the water displacement method

A

true or particle density

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30
Q

measurement of mass/volume

A

true or particle density

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31
Q

true or particle density is dependent on

A
  • grain moisture content
  • variety of grain sample
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32
Q

gives the proportion of void space between individual grains and the volume of bulk material

A

porosity

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33
Q

maximum angle at which the grain remains in equilibrium on an inclined surface

A

angle of friction

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34
Q

angle of friction is dependent on grain moisture content, volume and type of surface

true or false

A

false; not volume

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35
Q

inclination of hoppers

A

φf + 10 degree

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36
Q

force acting in the opposite direction of movement between two surfaces sliding against one another

A

friction

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37
Q

defined as the ratio of friction force between two materials and the force keeping them in contact

A

coefficient of friction

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38
Q

refers to the angle formed by the slope of a naturally poured amount of material with the horizontal

A

angle of repose

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39
Q

angle of repose is dependent on grain moisture and?

A

foreign matter

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40
Q

knowing the properties of the material help us to develop the ability not only to identify but also to determine the amount and composition of a material

true or false

A

true

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41
Q

importance of knowing properties of a material

A
  • market value of rice is signi affected by % of head rice grains; broken rice is less valuable than head rice
  • new varieties of grains are continually being developed; their properties must be determined to assess their suitability for mechanized handling and processing
  • degree of dmg due to grain processing is a function of physical and mechanical properties of the material
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42
Q

rice varieties can classified to dimensions of individual grains, which are

A

short
medium
long
long slender
medium slender

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43
Q

what can be used to measure grain dimensions?

A

vernier calipers or micrometers

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44
Q

combinations of size parameters such as minimum and maximum diameters, length, area, and perimeter

A

shape descriptors

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45
Q

ratio of mass of a body to its volume

A

specific gravity

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46
Q

can be determined by getting the weight of a grain sample that occupies a known volume

A

bulk density

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47
Q

for determining true density, __________ is used instead of water to minimize absorption by the grain

A

toluene (C7H8)

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48
Q

there is a positive linear connection between length, width, thickness, and equiv diameter as __________ increased

A

moisture content

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49
Q

force needed to initiate movement of material on a surface

A

static CoF

50
Q

force needed to maintain movement of material in contact with a surface

A

CoF

51
Q

refers to the removal of foreign or dissimilar material and may be done by washing, screening, hand picking

A

cleaning

52
Q

water that is used for cleaning should also be?

A

potable (safe to drink)

53
Q

aim of cleaning, sorting and grading is to?

A

handle and manipulate products so that they will yield the highest possible net return after being processed

54
Q

important prime consideration during cleaning, sorting and grading

A

initial quality of the raw products

55
Q

general procedures that may be used to improve, maintain or change the quality of a product

A
  1. control storage conditions
  2. kill or inhibit destructive organisms
  3. improve the physical characteristics
56
Q

phase or phases of the post-harvest system during which the impurities mixed with the grain mass are eliminated

A

cleaning

57
Q

refers to the impurities present in the paddy, which can be separated through sieves and other cleaning devices

A

dockage

58
Q

include underdeveloped and shriveled kernels that are hard to remove even with re-cleaning and/or rescreening

A

dockage

59
Q

dockage is determined to

A
  • protect processing equipment
  • separate the unripe and underdeveloped grains;
  • be able to adjust the hullers more precisely for minimum grain breakage in milling; and
  • be able to mill grain lots separately
  • decrease in quality of grain
60
Q

cleaning and sorting is based on the ff characteristics

A
  • size
  • shape
  • specific gravity
  • surface characteristics
61
Q

methods of cleaning and sorting grains, nuts and seeds

A
  1. winnowing
  2. screening
62
Q

a traditional/common practice of cleaning grains consists of tossing the grain into the air and letting the wind carry off the lightest impurities

A

winnowing

63
Q

winnowing eliminates the heavier impurities

true or false

A

false

64
Q

in winnowing, the grains are place in a _______ and slow winnowing leads to __________

A

container; separation

65
Q

almost all types of dry grain like wheat, maize, paddy, and pulses can be cleaned through screening

true or false

A

false; it can be cleaned through winnowing

66
Q

most widely used sorting device

A

screening

67
Q

it is used in conjunction with an air blast will satisfactorily clean and sort most granular products

A

screening

68
Q

this is done to remove dirt, spray residues, and other foreign material

A

washing

69
Q

washing may be continuous or batch type

continuous type is recommended only for small plants or institutional or community installations

true or false

A

false; it is batch type

70
Q

washing is performed by one or a combination of the following

A
  • soaking in still or moving water or other fluids
  • water sprays
  • rotary drum
  • rotating brushes
  • shuffle or shaker washer
71
Q

refers to the separation of the cleaned product into various quality fractions that may be defined on the basis of size, shape, density, texture and color

A

sorting

72
Q

sorting is desirable in heat and mass transfer operations, where ______________ ____ is a function of the size of the product

A

processing time

73
Q

fruits and veggies are sorted on the basis of

A
  • color
  • damage
  • size
74
Q

sorting fruits and veggies is related to quality classification

explain

A

sorting might involve separating fruits and vegetables based on factors like ripeness, size, color, or any defects that could affect their quality

this sorting process could be a step in ensuring that only high-quality produce is sold or consumed

75
Q

sorting may be done using

A
  1. screens
  2. diverging belts and roller sorters
  3. cylindrical and disc separators
  4. weight sorters
  5. color sorters
76
Q

subsequent processing operations following sorting

A
  1. blanching
  2. slicing
  3. filling of containers
77
Q

most sorting on the basis of color and damage is done using devices

true or false

A

false; it is done manually

78
Q

sorting

widely in sorting various grains, seeds, crystals, and other food pieces/particles of relatively small size

A

screens (flat or drum type)

79
Q

sorting

used to separate the fruits into various sizes by allowing them to pass through an increasing slot (opening) sizes

A

diverging belts and roller sorters

80
Q

sorting

used to separate nearly round grains (wheat) from long grains or particles

A

cylindrical and disc separators

81
Q

used for valuable food, such as eggs, cut meats, and sensitive fruits, where accuracy in size separation and caution in handling are needed.

A

weight sorters

82
Q

sorting

widely used in the food processing industry

A

color sorters

83
Q

operation of color sorter is based on the ________ ___ ________ _____ on food piece/particle, which is measured by a ______ _________

A

reflection on incident light; photo detector

84
Q

the classification of the material on the basis of commercial value and usage

A

grading

85
Q

grading is done mostly by hand

true or false

A

true; mostly by hand or through machinery

86
Q

sorting

separation of the products to their quality

A

grading

87
Q

the comparative commercial value of a farm product is a function of its grade factor and the different classifications are

A

a) physical characteristics (size, shape moisture content, color)
b) chemical characteristics (odor and free fatty acid)
c) biological characteristics (germination and insect damage)

88
Q

REVIEW QUESTIONS (no answer in the flashcard)

  1. How cleaning improve the quality of agricultural products?
  2. Explain the use of sieves in cleaning and sorting grains.
  3. Different the use of screens from roller sorters?
A

EXPLAIN

89
Q

effectiveness of hand grading depends on the following

A
  • quality of product
  • quantity per inspector and minute
  • experience and physical condition of inspector
  • kind of inspection
  • speed rate
90
Q

knowledge of various physical properties of grain crops is essential in guiding the development of the following:

A
  1. processing techs for pest control, disease control and value-adding
  2. machinery, facilities and handling sytems
  3. quality evaluation techniques
91
Q

in grading, products should be properly illuminated to should and it should move faster in front of the inspectors for increased efficiency

true or false

A

false; they should move relatively slower

92
Q

in grading, the products must not exceed a distance of more than ____ cm from the worker and the speed they are
moving in front of the workers inspecting them is 30m/min

identify + true or false

A

30 cm

false; the speed they are moving is product specific, no fixed rate for all

93
Q

this facilitates trade of common grains (specially paddy rice) in international and domestic markets

A

standardization of dimensions

94
Q

Philippine National Food Authority classifies kernels according to the ff standard

A
  • head rice
    more than or equal of 8/10 of whole kernel length
  • large brokens
    between 2/10 and 8/10 whole kernel length
  • brewer’s rice
    less than or equal to 2/10 of whole kernel length
95
Q

grading of larger quantities is based on?

A

it is based on testing of smaller quantities

***samples are taken out randomly and they are subsequently evaluated in the laboratory

96
Q

modern physical methods used in grading, specifically for color measurements

A
  • x-rays
  • lasers
  • infrared (IR) rays and microwaves
97
Q

machines used in grading can only be used in grading and not applicable for sorting

true or false

A

false; it can also be used for sorting of food

*** x rays are used in detecting foreign matter in food products

98
Q

what are used to measure grain dimensions?

A
  • vernier calipers
  • micrometers
99
Q

how accurate are vernier calipers and micrometers?

A

accurate to 0.001 to 0.0001 inches

100
Q

how are grains sorted to remove and separate the broken grains?

A

a rotating steel cylinders with indentations is used

as the cylinders rotate, broken grains that fit into the indentations are carried up and fall into a conveyor running along the axis of the cylinder

101
Q

combinations of size parameters such as minimum and maximum diameters, length, area, and perimeter

A

shape descriptors

102
Q

these can be used to identify crop varieties, detect foreign matter, and evaluate quality

A

shape descriptors

103
Q

physical property

can be estimated through resemblance to known geometric bodies such as spheres, cylinders, or ellipsoids, or by correlation with major dimensions

A

volume and surface area

104
Q

formula for volume and surface area

sphere

A

V = 4/3pir cube

SA = 4pir cube

105
Q

for determining true density, __________ is used instead of water to minimize absorption by the grain

A

toluene (C7H8)

106
Q

low surface tension of toluene ensures that small depressions are filled to obtain accurate results

true or false

A

true

107
Q

ratio of the friction force between two materials and the force keeping them in contact

A

coefficient of friction (CoF)

108
Q

force needed to initiate movement of material on a surface

A

static CoF

109
Q

force needed to maintain movement of material in contact with a surface

A

dynamic CoF

110
Q

factors that affect CoF include

A
  • surface moisture
  • grain moisture content and velocity
  • surface temperature
  • nature of surface material (conditioned or unconditioned)
111
Q

dynamic CoF is larger than static CoF

true or false

A

false; statis CoF is larger than dynamic CoF

112
Q

grain properties that affect angle of natural repose

A
  • shape
  • physical dimensions
  • maturity
  • surface frictional properties
  • moisture content
113
Q

methods of determining angle of natural repose

A
  1. method of emptying
  2. method of submerging
    a. method of piling
    b. method of pouring
114
Q

methods of determining angle of natural repose

material is poured out of a container and allowed to accumulate on a horizontal surface

A

method of emptying

115
Q

methods of determining angle of natural repose

a cone of material is slowly formed on a circular plate located inside the hopper by gradual removal from the bottom of the hopper

A

method of submerging

116
Q

methods of determining angle of natural repose

the material is allowed to flow onto a circular plate from a standard height

A

method of piling

117
Q

methods of determining angle of natural repose

material is first poured into a cylinder which is then lifted slowly and vertically to form a mound

A

method of pouring

118
Q

the angle formed by the material in a cylindrical container is also considered as the angle of repose

true or false

A

true

119
Q

method of pouring is appropriate for large grains

true or false

A

false; that’s method of emptying

120
Q

REVIEW QUESTIONS (no answer in this flashcard)

  1. Explain why moisture content of grain can have a significant effect on dimensions, shape and
    density.
  2. In what specific processing operation or equipment we consider the following physical properties:
    a) Bulk density
    b) Angle of repose
    c) Angle of friction
    d) Grain dimensions
A

EXPLAIN

121
Q
A