Module 2: Physical Properties of Common Agricultural Products Flashcards
(121 cards)
1
Q
any substance or moisture or mixture of substances that occupy a volume, and has a mass
A
material
2
Q
properties of a material
A
- appearance
- behavior
- name
- structure
- color
- order
- order
- composition
- any info about subtance
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
4
Q
market value of rice is significantly affected by what?
A
percentage of head rice grains
5
Q
what factors influence the degree of damage incurred during grain processing?
A
physical and mechanical properties of the material
6
Q
density and specific gravity are examples of which property of material?
A
physical characteristics
7
Q
physical characteristics - enumerate
A
- size and shape
- density and specific gravity
- volume
- surface area
- porosity
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
9
Q
imaging used to observe optical properties
A
- RGB image
- near infrared (NIR) imagery
- normalized difference vegetation index (NDVI)
10
Q
concerned with the strength or resistance of a particular crop when placed under stress
A
mechanical properties
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
12
Q
describe the movement of heat into or out of a material and how much it can sustain
A
thermal properties
13
Q
thermal properties - enumerate
A
- thermal conductivity
- specific heat
- emissivity
- thermal capacity
- surface conductance
- transmissivity
- thermal diffusivity
- absorptivity
14
Q
concerned with changes in sound transmitted through the material
A
acoustic properties
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
16
Q
changes in the transmittance of electromagnetic radiation, radio frequency and electrical energy
A
electrical properties
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
18
Q
electrical properties
A
- conductance
- capacitance
- dielectric properties
- reaction to electromagnetic radiation
- conductivity-ability of seeds to hold a surface charge
19
Q
physical properties of common grain crops
A
- grain dimensions
- volume and surface area
- density and porosity
- angle of friction
- angle of repose
20
Q
what are parameters measured in grain dimensions?
A
- length
- width
- thickness
- diameter
21
Q
physical property
basis for machine design, particle separation using sieves and grading
A
grain dimensions
22
Q
physical property
affect rates of heat and mass transfer of a material
A
volume and surface area
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
24
Q
physical property
calculation of the dimension of bulk storage facilities and intermediate holding bins of given capacity
A
density and porosity
25
density and porosity indicates the __________ degree of the grains
purity
26
aside from volume and surface area, which physical propertie/s are also necessary for studies on heat and mass transfer?
density and porosity
27
measures mass per unit volume, where volume includes pore spaces
bulk density
28
bulk density is dependent on
- grain moisture content
- foreign matter present
- variety of grain sample
29
this is measured using the water displacement method
true or particle density
30
measurement of mass/volume
true or particle density
31
true or particle density is dependent on
- grain moisture content
- variety of grain sample
32
gives the proportion of void space between individual grains and the volume of bulk material
porosity
33
maximum angle at which the grain remains in equilibrium on an inclined surface
angle of friction
34
angle of friction is dependent on grain moisture content, volume and type of surface
true or false
false; not volume
35
inclination of hoppers
φf + 10 degree
36
force acting in the opposite direction of movement between two surfaces sliding against one another
friction
37
defined as the ratio of friction force between two materials and the force keeping them in contact
coefficient of friction
38
refers to the angle formed by the slope of a naturally poured amount of material with the horizontal
angle of repose
39
angle of repose is dependent on grain moisture and?
foreign matter
40
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
true
41
importance of knowing properties of a material
- 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
42
rice varieties can classified to dimensions of individual grains, which are
short
medium
long
long slender
medium slender
43
what can be used to measure grain dimensions?
vernier calipers or micrometers
44
combinations of size parameters such as minimum and maximum diameters, length, area, and perimeter
shape descriptors
45
ratio of mass of a body to its volume
specific gravity
46
can be determined by getting the weight of a grain sample that occupies a known volume
bulk density
47
for determining true density, __________ is used instead of water to minimize absorption by the grain
toluene (C7H8)
48
there is a positive linear connection between length, width, thickness, and equiv diameter as __________ increased
moisture content
49
force needed to initiate movement of material on a surface
static CoF
50
force needed to maintain movement of material in contact with a surface
CoF
51
refers to the removal of foreign or dissimilar material and may be done by washing, screening, hand picking
cleaning
52
water that is used for cleaning should also be?
potable (safe to drink)
53
aim of cleaning, sorting and grading is to?
handle and manipulate products so that they will **yield the highest possible net return** after being processed
54
important prime consideration during cleaning, sorting and grading
initial quality of the raw products
55
general procedures that may be used to improve, maintain or change the quality of a product
1. control storage conditions
2. kill or inhibit destructive organisms
3. improve the physical characteristics
56
phase or phases of the post-harvest system during which the impurities mixed with the grain mass are eliminated
cleaning
57
refers to the impurities present in the paddy, which can be separated through sieves and other cleaning devices
dockage
58
include underdeveloped and shriveled kernels that are hard to remove even with re-cleaning and/or rescreening
dockage
59
dockage is determined to
- 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
cleaning and sorting is based on the ff characteristics
- size
- shape
- specific gravity
- surface characteristics
61
methods of cleaning and sorting grains, nuts and seeds
1. winnowing
2. screening
62
a traditional/common practice of cleaning grains consists of tossing the grain into the air and letting the wind carry off the lightest impurities
winnowing
63
winnowing eliminates the heavier impurities
true or false
false
64
in winnowing, the grains are place in a _______ and slow winnowing leads to __________
container; separation
65
almost all types of dry grain like wheat, maize, paddy, and pulses can be cleaned through **screening**
true or false
false; it can be cleaned through winnowing
66
most widely used sorting device
screening
67
it is used in conjunction with an air blast will satisfactorily clean and sort most granular products
screening
68
this is done to remove dirt, spray residues, and other foreign material
washing
69
washing may be continuous or batch type
continuous type is recommended only for small plants or institutional or community installations
true or false
false; it is batch type
70
washing is performed by one or a combination of the following
- soaking in still or moving water or other fluids
- water sprays
- rotary drum
- rotating brushes
- shuffle or shaker washer
71
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
sorting
72
sorting is desirable in heat and mass transfer operations, where ______________ ____ is a function of the size of the product
processing time
73
fruits and veggies are sorted on the basis of
- color
- damage
- size
74
sorting fruits and veggies is related to quality classification
explain
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
sorting may be done using
1. screens
2. diverging belts and roller sorters
3. cylindrical and disc separators
4. weight sorters
5. color sorters
76
subsequent processing operations following sorting
1. blanching
2. slicing
3. filling of containers
77
most sorting on the basis of color and damage is done using devices
true or false
false; it is done manually
78
sorting
widely in sorting various grains, seeds, crystals, and other food pieces/particles of relatively small size
screens (flat or drum type)
79
sorting
used to separate the fruits into various sizes by allowing them to pass through an increasing slot (opening) sizes
diverging belts and roller sorters
80
sorting
used to separate nearly round grains (wheat) from long grains or particles
cylindrical and disc separators
81
used for valuable food, such as eggs, cut meats, and sensitive fruits, where accuracy in size separation and caution in handling are needed.
weight sorters
82
sorting
widely used in the food processing industry
color sorters
83
operation of color sorter is based on the ________ ___ ________ _____ on food piece/particle, which is measured by a ______ _________
reflection on incident light; photo detector
84
the classification of the material on the basis of commercial value and usage
grading
85
grading is done mostly by hand
true or false
true; mostly by hand or through machinery
86
sorting
separation of the products to their quality
grading
87
the comparative commercial value of a farm product is a function of its grade factor and the different classifications are
a) physical characteristics (size, shape moisture content, color)
b) chemical characteristics (odor and free fatty acid)
c) biological characteristics (germination and insect damage)
88
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?
EXPLAIN
89
effectiveness of hand grading depends on the following
- quality of product
- quantity per inspector and minute
- experience and physical condition of inspector
- kind of inspection
- speed rate
90
knowledge of various physical properties of grain crops is essential in guiding the development of the following:
1. processing techs for pest control, disease control and value-adding
2. machinery, facilities and handling sytems
3. quality evaluation techniques
91
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
false; they should move relatively slower
92
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
30 cm
false; the speed they are moving is product specific, no fixed rate for all
93
this facilitates trade of common grains (specially paddy rice) in international and domestic markets
standardization of dimensions
94
Philippine National Food Authority classifies kernels according to the ff standard
- 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
grading of larger quantities is based on?
it is based on testing of smaller quantities
***samples are taken out randomly and they are subsequently evaluated in the laboratory
96
modern physical methods used in grading, specifically for color measurements
- x-rays
- lasers
- infrared (IR) rays and microwaves
97
machines used in grading can only be used in grading and not applicable for sorting
true or false
false; it can also be used for sorting of food
*** x rays are used in detecting foreign matter in food products
98
what are used to measure grain dimensions?
- vernier calipers
- micrometers
99
how accurate are vernier calipers and micrometers?
accurate to 0.001 to 0.0001 inches
100
how are grains sorted to remove and separate the broken grains?
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
combinations of size parameters such as minimum and maximum diameters, length, area, and perimeter
shape descriptors
102
these can be used to identify crop varieties, detect foreign matter, and evaluate quality
shape descriptors
103
physical property
can be estimated through resemblance to known geometric bodies such as spheres, cylinders, or ellipsoids, or by correlation with major dimensions
volume and surface area
104
formula for volume and surface area
sphere
V = 4/3*pi*r cube
SA = 4*pi*r cube
105
for determining true density, __________ is used instead of water to minimize absorption by the grain
toluene (C7H8)
106
**low surface tension** of toluene ensures that small depressions are filled to obtain accurate results
true or false
true
107
ratio of the friction force between two materials and the force keeping them in contact
coefficient of friction (CoF)
108
force needed to initiate movement of material on a surface
static CoF
109
force needed to maintain movement of material in contact with a surface
dynamic CoF
110
factors that affect CoF include
- surface moisture
- grain moisture content and velocity
- surface temperature
- nature of surface material (conditioned or unconditioned)
111
dynamic CoF is larger than static CoF
true or false
false; statis CoF is larger than dynamic CoF
112
grain properties that affect angle of natural repose
- shape
- physical dimensions
- maturity
- surface frictional properties
- moisture content
113
methods of determining angle of natural repose
1. method of emptying
2. method of submerging
a. method of piling
b. method of pouring
114
methods of determining angle of natural repose
material is poured out of a container and allowed to accumulate on a horizontal surface
method of emptying
115
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
method of submerging
116
methods of determining angle of natural repose
the material is allowed to flow onto a circular plate from a standard height
method of piling
117
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
method of pouring
118
the angle formed by the material in a cylindrical container is also considered as the angle of repose
true or false
true
119
method of pouring is appropriate for large grains
true or false
false; that's method of emptying
120
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
EXPLAIN
121
