EFFECT OF GRAIN TYPE AND STRAW TYPE ON

SEPARATION IN COMBINES

by

AKHIL SHANDILYA, B.E.

A THESIS

IN

AGRICULTURAL ENGINEERING

Submitted to the Graduate Faculty of Texas Tech University in

Partial Fulfillment of the Requirements for

the Degree of

MASTER OF SCIENCE

IN

AGRICULTURAL ENGINEERING

Approved

Accepted

December, 1987

/ ):'7

/';. 165 , ACKNOWLEDGMENTS

I wish to thank with sincere gratitute the following people for

their generous contributions towards this thesis completion.

I first would like to thank my chairman Dr. James M. Gregory for

his "big time" patience, his expert research guidance in helping me

write this thesis. My appreciation also goes out to Dr. Clifford

Feddler for being such an encouragement in getting this thesis

completed and also serving as a coimnittee member. My thanks also goes

out to Dr. Timothy A. Wiggins for his willingness to serve as a

committee member and for his practical questions that helped in

improving this thesis. My special thanks to Mr. James Snyder, for his

assistance and sound technical advice in building the shaker.

My special thanks to Mr. Marvin Dvoracek for being such a 'gem of a

man' in lending me his printer to type this thesis. Also I would like

to thank the Department of Agricultural Engineering for supporting me

financially during the course of my studies here.

11

TABLE OF CONTENTS

ACKNOWLEDGMENTS ii

LIST OF TABLES iv

LIST OF FIGURES v

CHAPTER

I. INTRODUCTION 1

Objectives of This Study 3

II. LITREATURE REVIEW 4

Basic Research on Combines 4

Cylinder Threshing and Separation 5

Separation on Straw Walkers 7

Effects of Crop Characterstics on separation . 10

Separation Models 13

Typical Laboratory Test Device 15

III. PROCEDURE 16

Construction of The Shaker 16

Experimental Procedure 19

Fraction of Cover Measurements 20

Parameters of Grains 23

IV. RESULTS AND DISCUSSION 25

Model Verification 28

V. SUMMARY AND CONCLUSION 38

REFERENCES 41

APPENDIX 44

111

LIST OF TABLES

TABLE

3.1. Values for k as, calculated by MERV and in litreature .... 22

3.2. Dimensions of grains used in the experiments 24

4.1. Measured values of static and dynamic resistances 26

4.2. Predicted steady state resistance using equation 2.5 31

IV

LIST OF FIGURES

FIGURE

3.1. Shaker apparatus used to gather separation data 17

4.1. Bar graph of static and dynamic resistances 27

4.2. Effect of three types of straw on two types on grain 29

4.3. Effect of five types of grains on separation through wheat straw 30

4.4. Predicted vs measured resistances with three straw types (wheat, soybean and sorghum) 32

4.5. Predicted vs measured resistances with two straw types (wheat and soybean) 33

4.6. Correlation between static and dynamic measured resistances 35

4.7. Mass retained vs longest grain dimension squared 36

CHAPTER I

INTRODUCTION

Harvesting by combines is a major practice in most of the developed

countries. High labor costs and short harvesting periods (because of

weather) have caused many countries to sponsor research to develop

mechanized methods of harvesting. This has improved the efficiency of

harvesting; has drastically reduced the harvest time involved; and has to

a certain extent standardized the quality of the harvested product.

During the earlier stages of development of harvesting machines,

cutters were pulled by horses and the harvested material was brought to a

hog thresher to separate the grain from the straw. Later when engines

were invented, the process of cutting, threshing, and separating was

built into one machine, the combine, which could be operated by a single

person. There are many types of combines available in various sizes and

shapes; but there are two main categories of combines; the pull type and

the push or self-propelled type. Many improvements have been made to

improve the efficiency of the combine and make it adaptable to numerous

crop and land conditions since its initial development.

Modern combines harvest many crops. Some of the major crops are

soybeans, wheat, barley, rice, corn, sorghum and peanuts. Combines

separate the seed from the plant material. A typical self-propelled

combine performs four basic functions: cutting, threshing, separating and

cleaning. The components that perform these functions are the following;

an intake mechanism consisting of reel, cutterbar and an auger (helps in

picking up the plant and feeding it to the next part), the cylinder

consists of a drum and a beater (threshes the grain from the plant), the

separator consists of walkers (moves the threshed straw mat forward

allowing the grain to separate), and the sieves usually located below the

walkers separate chaff from seed. On the floor of the combine is the

seed container which holds the seed. From here grains are fed to a

bigger container for storage.

Due to variations in crop and land conditions during harvesting,

continuous adjustments of various components on the combine are required

for maximum efficiency. Sophisticated quick-response mechemisms can

increase harvesting efficiency and reduce energy consumption, but the

goal is to get maximum harvest for least cost. Optimization requires an

understanding of the threshing and separation processes. Losses in a

combine are natural and occurs in all four beusic operations; cutting,

threshing, separating and cleaning. Even though all of these are carried

out by the combine, the latter three can be added together and termed

combine losses. Major reasons for these losses are the following:

1. Improper clearance in the cylinder

2. Improper feedrate

3. High moisture content

4. Short walker lengths

5. Improper maintenance, e.g., clogged sieves

Even though major research has been done in areas of reducing losses,

there are no standard designs or management procedures to achieve an

optimum harvest of grain in present machines. This can be attributed to

a limited understanding of the major variables affecting the process.

The process of separation occurs in two major sections of the

combine, the cylinder and at the straw walkers. Cylinder separation

occurs immediately after the threshing process of setting free the grains

attached to the plant material. The straw walker performs only the

separation process. There are many factors influencing the process of

separation at both stages and these factors have been studied and

mathematical models have been derived to predict separation at these

stages. Two recent authors Gregory and Fedler (1986) have developed an

equation to predict separation on straw walkers. They have determined

that straw type and grain type should affect grain separation. Because

insufficient data is available to evaluate the affect of straw type and

grain type, there is a need for further research to substantiate this

theory.

Objectives of This Study

(1) To study the effect of grain and straw type on separation

including the construction of a laboratory test apparatus and the

collection of experimental data, and (2) to use collected data to test

the proposed separation model reported by Gregory and Fedler (1987).

CHAPTER II

LITREATURE REVIEW

Basic Research on Combines

Man's quest for automation of labor intensive farm jobs has caused

major changes since the early 1800's, especially in the area of

harvesting and separation of the edible from the inedible (John Deere

Manual). The achievement of this automation has involved many man hours

of research and experiments in the laboratory as well as in the field.

During the process of automation it is necessary to acquire extensive

knowledge of the material being processed in order to adapt machinery for

the various natural conditions that exist in crops (Stephens and Rabe,

1977). Boyce et al. (1974) are of the opinion that designs of combines

have reached their limits with respect to their lateral sizes. They

suggested that further improvements should occur by making each component

more efficient. One way to make separation more efficient is to develop

a more detailed knowledge of the effect of plant material properties on

separation.

Separation begins with threshing, which is the action of beating the

grain out of the pod or off the cob. Separation of grain from straw

begins immediately after the grain is detached. Approximately ninety

I>ercent of separation can occur in this early stage before the material

reaches the straw walkers (Arnold, 1964 and John Deere Manual). This

early stage consists of a cylinder and a concave. The cylinder rotates

while the concave remains stationary. The concave may be solid or have

open slots. Separation is enhanced with open slots (Arnold and Lake,

1964). The beater which is located above the cylinder exit, pushes the

threshed material onto the straw walkers where the next stage of

separation occurs. Walkers spread and mix the material, allowing the

grains to fall through the straw and sieves. The trash or material other

than grain (MOG) is moved through and out the combine. While literature

on performance of cylinder, concave, and straw walkers is available, very

little research has been reported that deals with the basics of

separation or the modeling of the process.

Cylinder Threshing and Separation

Threshing can be accomplished by (a) repeated impacting on the

material, (b) rubbing action, (c) squeezing the grain out of pod, (d)

centrifugal force to separate heavier grain from the stalks, or (e) a

combination of two or more of these actions (Kepner et al., 1982). The

most used methods are the centrifugal and impact methods of threshing.

The three basic mechanisms used for threshing are cross-flow rasp-bar

cylinders, axial-flow rasp-bar cylinders and spike-tooth cylinders

(Kepner et al., 1982). The usual dimensions of rasp-bar and spike-tooth

cylinders are in the range of 0.48 to 0.61 m in diameter and, 0.69 to

1.53 m in width. The concave length varies from 0.33 to 0.51 m.

Gasparetto et al. (1977) using high-speed motion picture, studied the

mechanism of threshing and separation at the cylinder and concave. They

observed that the major cause of threshing is the shattering action

produced by the impacting of the rasp-bar at high speeds. The primary

function of the concave is to hold and feed straw for repeated impacts by

the rasp-bar (Arnold, 1964). The clearance between the cylinder and

concave is of importance to control the amount of threshing and the

quality of grains detached. The larger the spacing, the farther into the

concave the material moves before threshing occurs (Kepner et al., 1982).

Concave spacing is typically wedge shaped. This shape helps provide

smooth feeding of the straw and prevents clogging at the exit. The

spacing is adjusted by trial and error by looking at the trash (MOG)

output from the combine. First the concave spacing is adjusted for non­

crushing of both straw and grain. Then the cylinder speed is adjusted

for maximum separation of grain without breakage (John Deere Manual).

Logically, the spacing is big for large grains and small for small

grains. A maximum clearance of 4 to 5 cm is used for corn (Kepner et

al., 1982). The grains that are detached fall through the concave grate

and are fed to the shoe area for cleaning before flowing into the storage

bin. Arnold and Lake (1964) compared open and closed concaves. They

found open concaves performed better giving good results with respect to

amount of iindamsiged seeds and separation.

Goss et al. (1958) conducted experiments on conventional combines

with the objective of determining optimum adjustments and operating

conditions for each crop in order to minimize seed losses and seed

damage. They found that increasing the cylinder speed reduced the walker

losses because more separation occurred at the cylinder. Also the walker

losses were independent of the concave settings when the walker

efficiency was considered from the amount of seed, straw and chaff

delivered on to the walker entrance. With two different grain/non-grain

ratios, they found the higher grain/non-grain ratio yielded more chaff

and straw on to the walkers and increased the grain loss at the rear of

the ccMobine.

Studies were conducted on separation characteristics by Wurbleski and

Smith (1980) on three types of combines: conventional John Deere 6600

(cylinder and concave with straw walkers), non-conventional Western Roto

Thresh (cylinder and concave with perforated drum) and Sperry New Holland

TR70 (axial threshing and separating rotors). Their results showed that

the centrifugal tjrpe (TR70) of separation was the most efficient for

barley and wheat. The amount of seed damaged WEUS also the least in the

centrifugal type (TR70). Nothing was mentioned about the crop

properties.

Separation on Straw Walkers

Only loose grains are separated on straw walkers. Straw walkers

can be of two types; the rotary type and the multiple-section straw

walkers. Multiple-section straw walkers are made up of three to five

straw walkers mounted side by side and connected by two multi-throw

crankshafts at the extreme ends. These are used in conventional

combines. The walker bottom has different kinds of openings for grain to

fall through. Rectangular, square and hooded type openings are common

(John Deere Manual). Straw walkers have to be mounted at an angle for

longer dwell time and better separation of grains. In order to prevent

backsliding of straw the edges of the walkers are provided with fishbacks

or fins (Boyce et al., 1974). For each throw of the crankshaft the straw

mat is thrown up and rolled further to the rear of the machine. Through

8

this motion, the grains are separated from the straw mat. Boyce et al.

(1974) studied separation on straw walkers and found that separation was

maximum at one third the straw walker length and separation was low at

the extreme ends. They concluded that more fundamental research was

needed to explain the phenomenon of separation. The typical dimensions

of straw walkers are 0.2 m to 0.31 m wide and about 2.4 to 3.05 m long

with a throw of 0.10 m (Kepner et al., 1982).

Much has been done to predict the rate of separation on straw walkers

by many authors over the last two decades. Reed et al. (1974) predicted

that smaller amounts of grain were left on the walkers if the length of

straw walker was increased. This was based on the previous work done by

the same group in which they found that the separation followed a

exponetial decay pattern over the length of straw walkers. Wang et al.

(1985) did further work in this area and provided a means of calculating

the constant *b' which was called the attenuation coefficient used in the

prediction equation. They reported this coefficient to be numerically

equal to the separation efficiency over a very small length of the

walker. They also set a standard to do comparison work on separation

performance of combines. Gregory and Fedler (1986) also derived a

separation predicting equation. They used the fundamentals of diffusion

and included material properties such as seed size and straw type.

Non-conventional rotary separators are of two major types. The first

is stationary grates and rotors where the rotors spin at high speeds

forcing the grain out through the grates as the straw and grain are

pushed back by the rotor blades. The second is a perforated drum type

which has a rotating drum with smaller openings than the stationary

grates and an auger mounted close to the drum surface. The auger pulls

the straw and grains off the surface and thus agitates the straw mat and

helps in separating the grain from straw. A detailed study of this

system has been done by Jan et al. (1974) at Saskatchewan. They found

this to be an efficient separating device at different feed rates. A

blower is used to push the thrash out through the rear of the combine.

The speed of the drum is considerably slower than the rotor speed. The

difference in centrifugal forces between the two types is of the order of

two hundred times the force of gravity (Kepner et al., 1982). Both

threshing and separation can be achieved with two hundred times the force

produced by gravity when conditions are dry enough (Kepner et al., 1982).

The idea of integrating both threshing and separation was first tested by

Lamp and Buchele (1960). Jan et al. (1974) observed that high

centrifugal forces caused the plant material to block the holes in their

perforated drum experiment. Buchanan and Johnson (1964), in their

experiments with a conical threshing and separating device, cautioned

against grain damage caused by grains hitting the collecter surface after

going through the screen. It was also difficult to provide axial motion

to the crops at high centrifugal forces. Long et al. (1969) obsereved

that separation was higher when there was an ample amount of agitation

with the centrifugal force. Srivastava et al. (1974) found that the

problem of obtaining agitation and movement of material along the drum

surface could be solved by changing auger blade angles and screen to

blade speed ratio. The usual diemensions of these separators are about

0.45 m in diameter and about 2.75 m in length (Kepner et al., 1982).

10

Effects of Crop Characterstics on Separation

Some of the major crop characterstics that affect the performance of

separators are :

1. Thickness of straw mat,

2. Moisture content of crop,

3. Type of grain and straw,

4. Grain to non-grain ratio, and

5. Straw length.

Thickness of straw mat. If the thickness of the straw mat increases,

there is a reduction in the amount of threshing in the cylinders. To

compensate, the material must move further along the concave before

threshing is completed. Delayed threshing delays grain separation in the

cylinder and increases the amount of non-threshed grains, hence high

losses at the cylinder (John Deere Manual). Delayed threshing also

increases the amount of grain to be separated on the straw walker. The

thickness of the straw mat also affects the straw walker directly. The

time taken for a grain to go through 5 cm of straw is smaller than for a

10 cm thick mat for the same shaking speed (Long et al., 1969).

Moisture content of crops. A higher moisture content of up to 20% wet

basis has been tested for separation on straw walkers by Reed and Zoerb

(1972). They found no change in the efficiency of walker performance

associated with grain moisture using two different types of straw

walkers. It was found that germination is reduced when grains are

threshed at moisture contents other than the normal range of 17 to 22%.

High moisture content appears to affect threshing (Arnold and Lake, 1964)

11

but not separation (Reed and Zoerb, 1972). Srivastava et al. (1974)

noted that in the case of conical or cylindrical thresher and separator

the axial movement of straw matter was sensitive to the moisture content

of the crop.

Type of grain and straw. Few researchers have investigated the effect

of type of grain and straw on separation. Stephens and Rabe (1977)

stressed the need for more study on crop physical characterstics and

conditions to improve productivity in mechanical harvesting. There is

mention of type of grain and straw having effect on separation by Huisman

(1977). Gregory and Fedler (1986) stated that both straw mat thickness

and grain size affects separation in a combine. Huisman (1977) noted

that particle size distribution of straw has more affect than straw bulk

density on separation. From the literature it appears that more research

is needed in this area.

Grain to non-grain ratio. Increasing the non-grain (MOG) content

decreases seed damage, but reduces detachment and separation at the

cylinder. An increase in the grain/non-grain ratio at a constant feed

rate decreases both cylinder and walker losses for most grains (Reed et

al., 1974 and Kepner et al., 1982).

Length of straw. Long straws tend to cause poor separation at both

the cylinder and straw walker (John Deere Manual). This also could add

chaff into the grain bin, or cause the combine shoe to get clogged.

Straws tend to break when they are long and their moisture content is low

(Reed and Zoerb, 1972). This can lead to low efficiency of separation at

12

the straw walkers, and also at the shoe. Long straw lengths increase the

MOG to grain ratio and are thus undesirable for machine harvesting.

The major factors that affect threshing and separation have been

reviewed at this point. One fact which should be noted is a constant

crop condition is hard to find in the field (Huisman, 1977). Enough

research has been done in the field to determine the technical

feasibility and optimum operational parameters of different components of

the combine in relation to crops under varying conditions (Nyborg et al.,

1969). However, insuffecient data exists to fully evaluate the effect of

straw type and grain type on separation. This could highly influence the

efficiency of harvesting grains.

Grain separation in general can be visualized as grain movement

through the open spaces that occur in the complex arrangement of straw

matter. If the amount of open spaces are large then practically all the

grains should flow through the straw mat. Similarly if the open spaces

are small and less in number, then the amount of grains that can flow

through is very small. In other words, fraction of cover of straw per

unit area determines the amount of grains that can flow through that unit

area. Using this principle, Gregory and Fedler (1987) have developed, an

equation to predict the amount of grain that can be retained given the

area of cover, the type of straw, its thickness and the size of grain.

13

Separation Models

Reed et al. (1974) presented a simple model to predict grain

separation (eqn 2.1). This model was developed by curve fitting data

points obtained experimentally.

Gr/Go = e-^^ [2.1]

Gr = Grain remaining on the walkers.

Go = Grain onto walkers,

b = F(feedrate, MOG/grain, moisture content, crop variety and

walker design),

L = Length of walkers.

The model developed by Gregory and Fedler (1987) to predict the rate

of separation of grains on a straw walker was derived using Picks law of

diffusion (eqn 2.2). Note the similarity to eqn 2.1 in term of the

length variable.

Gf/Gi = e-[((P/X2) Va W BdM0G/M)e-»^C3M/(w v>] L [2.2]

Gf = Final mass of grain,

Gi = Initial mass of grain,

P = Machine vibration energy constant,

X = Diameter of grain,

Va = Average velocity of particle,

W = Width of the separation area,

BdMOG = Bulk density of MOG,

M = Mass per unit area of MOG,

k = Projected area/mass for a average piece of MOG,

14

C3 = A constant to reduce the total mass to an effective mass,

V = Flow velocity,

L = Length of separation area.

In equation 2.2 the power term is the lumped diffusion constant (Lc)

also called the attenuation coefficient in equation 2.1. This lumped

constant can be reduced to eqn 2.3 by holding all variables constant

except for the size of grain and straw type.

Lc = (Bi/X2)e-B2»^. [2.3]

In this equation Bi and B2 are constants and Lc represents the lumped

diffusion coefficient b, which contains the diffusion constant. The

reciprocal of this factor should be the resistance. Taking the inverse of

this gives equation 2.4.

1/Lc = (X2/Bi)eB2»^. [2.4]

The resistance (1/Lc) is in a sense a measure of the ease with which

the grain tumbles to the bottom of the straw mat. When the straw

material is not remixed, grains become trapped in the straw and do not

easily separate from the straw. For this condition the grain moves

through layers of straw with some grain stopping at every obstacle in the

flow path. Each layer has a thickness of the length dimension of grain.

For this condition, B2 is equal to M * X / DT or mass per unit area

divided by the ratio of total thickness of straw (DT) by longest grain

15

dimension (X). The unit resistance offered for each layer [X̂ *

eM*k*x/DT] is multiplied by DT / X to predict resistance for the whole

thickness of straw mat. Substitution of a unit value for Bi and the

above relationship for B2, gives the following equation for resistance.

1/Lc = (X2/l)*e<M*tc*x/DT)*DT/x. [2.5]

Typical Laboratory Test Device

To study the process of separation on straw walkers Reed and Zoerb

(1972) and Reed et al. (1974) used straw walker parts to build their

experimental device in the laboratory. This used a lot of crop material

and needed special equipment to maintain constant material conditions.

Other authors have successfully carried out research with smaller devices

which do not actually duplicate the action of the straw walker assembly.

Baader et al. (1969) used a crank mechanism to give a vertical motion to

their experimental setup. Huisman (1977) also used a vertical motion to

conduct his experiments on the process of grain separation. Gregory and

Fedler (1986) used a small hand shaker to verify their exponential decay

model for grain separation. Since a straw walker assembly and a large

amount of material was not available, it was decided to construct a

simple device that could shake and hold less amount of material for this

research.

This study will focus on collecting more data to test the equation

developed by Gregory and Fedler (1987) (equ 2.4). Equation 2.4 will be

tested indirectly by varying only the size of grain and type of straw

using eqn 2-5.

CHAPTER III

PROCEDURE

Construction of The Shaker

A mechanized shaker was built to investigate the effect of straw and

grains on separation. The design objectives of the shaker were (a) keep

size small so a minimum of crop materials would be needed to perform

tests, (b) keep cost low and (c) produce a test procedure that could

easily detect the effects of grain size and straw type.

The shaker was built using materials available in the Agriculture

Engineering Department. The device, as shown in figure 3.1, was

constructed as a wooden box 0.5 m by 0.5 m and 15 cm deep using plywood.

A wire mesh of 1.3 cm square openings was attached to the bottom of the

box with the help of a sheet metal frame. This box was supported by a

square angle-iron frame mounted on a tripod of three flat strips of iron

legs of approximately 0.6 m in length, 2.5 cm in width and 0.5 cm in

thickness. To the bottom of these legs was welded another larger frame

which could support the shaker, the electric motor, and the cam shaft

assembly. A 186 W electric motor was used to power the shaker. The

motor had a rotation speed of 1725 RPM. A belt pulley mechanism was used

to reduce the speed to about 200 RPM. The larger pulley was mounted on

one end of a shaft 1.2 cm in diameter. This shaft mounted between two

bush bearings also had two cam with a throw of 2.5 cm welded on to it,

converting the rotary motion to a shaking action. The cam moved against

16

17

Fig 3.1 Shaker apparatus used to gather separation data.

18

the two flat strips of iron flats which supported the box frame. The

grain was recovered through a hopper built of sheet metal beneath the

sieve. The hopper was mounted to the bottom of the wooden box. The

square opening of the hopper was 6.25 cm^. The motor assembly was

provided with slots on the bottom of the mounting plate to adjust the

tension on the belts.

The construction of the sample collector was done after many trials

of different types of straw and grain combination runs. The amount of

grain collected for about ten seconds decided the size of the sample

boxes (10 cm X 15 cm x 5 cm deep). Eight sample boxes were held in

sequence and aligned on a guide to collect samples. The frame to hold

the plastic boxes was built using plywood. The eight boxes were placed in

little compartments placed side by side on its 10 cm side. This sample

collector was pulled against sheet metal restrictors which were mounted

on a rectangular plate. The plate was mounted on to the frame. Grains

were collected at the center of the plastic boxes to avoid grain

scattering out. The sample collector was pulled by hand at every sample

collection interval.

The shaker was first intended to study the exponential decay model

devoloped by Gregory and Fedler (1986). Due to non-mixing of straw and

grain during sample collection it failed to provide a true exponential

decay of grains through straw. Also grain ceased to separate out after

two minutes of shaking. Based on this observation and assuming that the

amount of trapped grain was an indication of resistance to separation,

the study was modified to the following procedure.

19

Experimental Procedure

Three types of straw and five types of grains were used in the data

collection process. The straw types were sorghum, wheat, and soybean.

The five types of grains were birdseed, sorghum, cottonseed (treated),

blackeye peas and corn. The thickness of straw was kept constant at

three inches and the initial amount of grain was kept at one kilogram.

For each type of straw, all five types of grains were run through. Five

replications of each type of seed with eight sample collections were run

with each type of straw. The time interval of collecting samples was as

follows; the first sample was for a three second duration, the next six

samples were of a ten second duration, and the last sample was of sixty

seconds. This experimental design provided independence between the

variables of grain size and straw type. The use of natural materials

(each grain in its own straw) would not achieve independent evaluation

and would have hindered statistical evaluation.

One kilogram of grain was weighed and poured evenly over the straw

mat. The grain that fell through the mat were collected and poured back

over the mat. This was done three times for full grain saturation of

straw. The grain that over flowed and fell through (OF) after the third

time was weighed and the remaining grain on the straw mat was termed the

static resistance (SR) (the resistance offered by the straw mat to the

grains when the shaker is static). Next, the shaker was turned on and

samples were collected in sequence for the time intervals explained

above. The samples were then weighed consecutively, substracting the

initial amount of grain on top of the straw mat before shaking (SR) and

the total amount of grain collected after shaking (TGC), the remaining

20

amount of grain in the straw mat was calculated and was termed dynamic

resistance (DR) (the resistance offered by the straw mat to the initial

saturated grain content after it has undergone shaking). The data of

grain masses collected was run through a simple basic program to do the

mathematics to print out the average of grains collected at every sample

box and the average of static and dynamic resistances offered by the

straw to that particular type of grain, using the following

relationships.

1000 - OF = SR [3.1]

SR - TGC = DR [3.2]

Quality of Straw and Grains. The straw and grains were dry with an

average moisture content of 8.8Si. Expcept for wheat straw, the other two

types of straw were harvested trash out of combines. They were clean and

free of chaff. The wheat straw was baled after cutting for cattle feed.

It had some wheat kernels and chaff in the straw. The length of wheat

straw was 20 to 25 cm. The other straws consisted of highly mixed

lengths.

Fraction of Cover Measurements

During the course of the experiment and analysis it was necessary to

measure the fraction of cover because the standard k factor data provided

in litreature for the straws did not include wheat straw with chaff and

kernels. Fraction of cover for all three straws were measured by using a

wooden frame one meter square laid on the floor. Into it was randomly

scattered a small amount of straw. Then a yard stick was placed over the

21

straw cover and the number of points out of 25 covered by straw were

recorded. An average of eight such random measurements inside the wooden

frame was used as the fraction of cover. The ratio of the number of

points covered by the total number of points, namely 25, gives the

fraction of cover.

Evaluation of k Factor. After the fraction of cover measurement was

made, the amount of straw inside the meter square area was weighed to

calculate the k factor. The fraction of cover (F) and mass (M) in kg/ha

were plugged into the fraction of cover prediction equation as developed

by Gregory, (1982), eqn 3.3.

F = 1 - exp(-k * M) [3.3]

where, F = Fraction of cover,

k = Coefficient,

M = Mass of straw in kg/ha.

Using the above equation, the k value was easily calculated. This

was carried out for several different fraction of covers for all three

types of straws. Fraction of cover ranged from 0.21 to 0.90. To

calculate the best k value, the model with the data points were evaluated

by using MERV, a statistical evaluation program (Gregory and Fedler,

1985). The model fit the measured data with an R2 equal to 0.865 or

better for all three types of straw and with a significance level of

greater than 0.05. The k values obtained were reasonably close to

published data (see table 3.1).

22

Table 3.1. Values for k as, calculated by MERV and in litreature.

STRAW TYPE

WHEAT

SOYBEAN

k VALUE MEASURED

0.000652«

0.000227*

k VALUE PUBLISHED REFERENCE

0.0005<»«

0.0002*

Gregory (1982)

Gregory (1982)

SORGHUM 0.000171* 0.00006* Greb (1967)

* - Combine trash, # - stem only, © - baled wheat, ©@ - standard value.

23

Parameters of Grains

The length, breadth and thickness or the dimensions along the X,Y and

Z axis of grains were available in litreature for all tjrpes of seeds

except cottonseed and birdseed. Actual measurements were made for the

two types of seeds. An average of ten ramdom sample measurements of

three sides of the grain, made by a digital slide calliper were taken as

the standard dimensions of the grains used. These dimensions are

presented in table 3.2.

24

Table 3 . 2 . Dimensions of grains used in the experiments (cm).

GRAIN TYPE REFERENCE

BIRDSEED

SORGHUM SEED

COTTON SEED

BLACKEYE PEAS

CORN

0.228

0.443

0.8635

0.8785

1.086

0.220

0.367

0.539

0.6845

0.777

0.1715

0.255

0.484

0.561

0.500

Measured

Mohsenin,

Measured

Mohsenin,

Mohsenin,

1986

1986

1986

CHAPTER IV

RESULTS AND DISCUSSION

One of the main objectives of this study was to collect data to

verify the model as developed by Gregory and Fedler (1987) as shown by

equation 2.4. The experiments were conducted with three types of straw

and five types of grains as explained in chapter III. The data collected

is presented in the Appendix along with the results obtained by the basic

program. The results contain the static and dynamic resistances of the

grain and straw combinations along with the mass collected in each sample

box. The static and djmamic resistances of the different treatments are

tabulated in table 4.1.

The static and dynamic resistance data are plotted as a bar graph as

shown in figure 4.1, the straws and grains are arranged in descending

order of average thickness and lengths. The graph clearly shows the

effect of straw type and grain type in both the static and dynamic

sections of the graph. The larger the size of straw the lower the

resistance offered and the smaller the straw, the higher the resistance

offered, irrespective of grain size in both sections of the graph.

Looking at the graph from the grain perspective in the dynamic section,

the larger the grain size, the higher the resistance and the smaller the

grain size the lower the resistance to movement irrespective of the straw

size. In combination, small size straw and big grain sizes offer higher

magnitudes of resistances than a large size straw and small size grains.

25

26

Table 4.1 Measured values of static and dynamic resistances. (all values in grams)

GRAIN TYPE

STRAW TYPE CORN BLACKEYE PEAS

COTTON SEED

SORGHUM SEED

BIRDSEED

WHEAT STATIC

DYNAMIC

1000 1000

394.6 245

1000

279

1000

58

716

13

STATIC SOYBEAN

DYNAMIC

STATIC SORGHUM

DYNAMIC

929

155

624

49

942

158

485

82

954

97

670

59

468

27

495

43

140

21

208

25

27

K..W(^<<<«^# K \ \ \

^ ^

I . J

n c; o c CD

09 •H 00

u

U I •H .p >»

(0 *

o

CD

to u m m

tc •H

( • p U O B D O m ) ( a i 6 ) NIVUO JO SSVIN a 3 N I V i 3 »

28

Indirectly the fraction of cover of straw matter in the box has a lot to

do with the resistance offered to grains. Since the effects are evident

in the dynamic section of the graph it clearly shows the prevalence of

the effects even after the process has reached steady state. The steady

state process can easily be seen in the plot of mass collected vs time in

figure 4.2. This graph also shows the effect of straw types on different

grain sizes (corn and blackeye peas). Figure 4.3 shows the plot of one

type of straw and five different grains vs time. It clearly shows that

different grain sizes influence the process of separation by the

different decay slopes.

Model Verification

The model (Gregory and Fedler, 1987) was developed for the steady

state process and equation 2.5 has been utilized to predict the

coefficient 1/Lc in this study. The predicted data has been tabulated in

table 4.2. The model was verified with a linear relationship between the

predicted and measured data using a statistical package MERV ( Gregory

and Fedler, 1985). The result was an R̂ of 0.852 with a significance

level alpha of 0.001. This proved that the model fit the data well.

After plotting the data on a graph (figure 4.4) it was observed that the

sorghum data was causing much of the scatter. The model tended to

overpredict the sorghum data. When this data was removed from the

analysis, the R̂ increased to 0.961 (figure 4.5). The significance

remained high (alpha = 0.001) even though the number of data points were

reduced. The overpredict ion of the sorghum straw data could be due to

many reasons. It could be an inadequacy of the model to account for some

other factors that are affecting the process, when the fraction of cover

29

c c c a a c 0 >» > o cj m m u 1 I I I o o £ JC

o o o

n cu

o

c o

OD

u n

<H o n

u

<H 03 O C

•P (0

o u

b3 O

eg

\30 • H Ex.

(B) aaioamoo SSVH

30

c o •H

CO u CO a oo c o B

•H (0

O

05 •

* * •»->

03 4)

>H fl CH «)

V o (H i-i (H J C

CO t

to • H E>4

(0) a3io3"noo SSVH

31

Table 4.2 Predicted steady state resistance using equation 2.5.

GRAIN TYPE

CORN

BLACKEYE PEAS

COTTON SEED

SORGHUM SEED

BIRD SEED

SORGHUM STRAW

1175

890

870

390

187

SOYBEAN STRAW

1302

966

943

406

191

WHEAT STRAW

2928

1863

1797

565

227

32

CD .

•P to

•H LI

* g §

go 3 •H 4) OS . p

u, o 09

0) « U -P 9 CO

SI H ^

00 > OD

9)

-o a 4) >^

. a , •O CO 4) IM

Pu 09

to •H &C4

o o o en

o o ID Ol

o o o Ol

o o lO «-l

o o o ^^

o o lO

Ol/T lN3I0Idd300 03iOI03Ud

33

o o o m

o o in C\i

o o o (U

o o in wi

o o o ^<

o o in

i •P •H %

09 4) O

g OB

•H «9 4)

4) ki

s

4)

•6 O OQ

S •P CO 4)

i 09 > 09

4) •̂ a 4) >»

4-> - p

•H 2 t3 CO 4) U U -M

QL, n

to •H

OVT iN3I0I4J300 a310ia3bd

34

of straw is very small. Since most of the grains were being held by the

sorghum head and the sides of the shaker, it is reasonable to assume that

the small amount of trapped grain on the sides of the shaker starts to

dominate when total trapped grain is small proving that at this stage the

equipment fails to give true data. From a practical point of view, this

type of material does not limit separation in combines. Errors, even

though they seem relatively large on the graphs are of little practical

significance in the field.

From the observation of static and dynamic resistances from the bar

graph (figure 4.1) there appears to be some similarity between the two

resistances. For analysis, some of the static resistance data points had

to be neglected because the experiment was restricted by the amount of

grain poured (1 kg) on to the surface of the straw mat. Therefore, the

data points with static resistainces of 1 kg had to be removed for

analysis. After doing the statistical analysis it showed a linear

functional relationship with an R2 of 0.509 (figure 4.6). While the R2

was much lower than the other results, the relationship was 95*

significant or alpha = 0.05.

Gregory and Fedler (1987) resistance equation (eqn 2.4) was further

established by the data collected. The equation resistance term 1/Lc is

directly proportional to the square of the longest grain size. The mass

retained in grams vs the square of the longest grain dimension clearly

shows a linear relationship (figure 4.7). Wheat and soybean straws gave

an R2 of 0.989 (alpha = 0.001) and 0.85 (alpha = 0.01)

35

o o 4) U 3 09 CO 0) B o

•H

o in £

•«

UJ

z < 1 -

100

ES

IS

s u

lAM

i

> Q

o in

•1-1

CD 4^ CD

C3 4)

1 •4J 4)

.D io

n ce

s.

CO o i-H 4-> 4> 09 (M - H Ui 09 0 9> O I-

CO

to •H

o o o o in i^

o o in

o in m

(6) 33NVlSIS3b] 3I1V1S

36

in (VI ^

§J3 - ^ * « i

E E

^^

Q (L < 3

Z O M

cn z UJ z M

^ Q O in z M

GR

A

I -(fl LLI (0

• •u 4) U CO 3 C 09

B 0

• H OS B 4) B

• H

-o B

• H CO ( N

to 4J 09 4) to B o

f i

m >

•o 4) B

• H

reta

09 CQ CO

z (VI o

to •H

(0) 03NIV13d SSVH

37

respectively, but sorghum did not show a significant linear relationship.

The experimental error for this study appears to have been too large to

detect the small slope for the grain sorghum.

The major analysis thus far has been on the dynamic resistance. This

resistance appears to be closely related to the resistance of grain

separation in combines. While the static resistance may not be important

for combines, it may have application in aerial seeding of crops over

soil covered with residue. This practice is used some in conservation

tillage and by the highway department along road sides.

The most important result is that the static resistance is more than

twice as high as the dynamic resistance. When possible, seeding should

be performed before mulching, especially when large seeds and thick

mulches are to be used. If this is not possible, then it is important

to switch to dynamic conditions by disking or some other method of

shaking the straw.

The second most important result is that at least a weak linear

relationship exists between static and dynamic resistance. Since we have

an equation to predict dynamic resistance, interms of seed size, straw

type and straw thickness, it is possible to first predict dynamic

resistance then use dynamic resistance to predict static resistance. The

computed static resistance can then be subtracted from the amount of

grain applied to obtain the amount of grain reaching the soil.

CHAPTER V

SUNWARY AND CONCLUSION

From the literature, it was established that more research was needed

to determine the effect of crop materials on grain separation in

ccnnbines. From the separation model proposed by Gregory and Fedler

(1987), two variables were selected to characterize crop materials: grain

size and a residue coverage coefficient, k. The objective of this study

were to vary these two variables and measure their effect on grain

separation.

A simple shaking device was constructed in the shop to make the

tests. Originally the experimental device was constructed to study the

exponential decay of grain separation as a function of time. But, due to

the non-mixing of the straw material, this procedure was modified; and

the amount of grain retained after two minutes of vibration was used as a

measure of resistance to separation. With the data collected, it was

clearly verified that grain size affected separation (figure 4.6). Straw

type was also shown to affect separation (figure 4.1). This was further

established by the statistical and numerical evaluations done using the

data collected with the help of statistical packages. The level of

significance and the R2 provided by the results proved the adequacy of

the proposed separation model by Gregory and Fedler, (1987).

38

39

From the above results with different sized grains and straw types,

it is concluded that crops with long grains such as oats will be the most

difficult to separate. Crops with high crop coefficients (k), such as

barley, wheat, oats or straw with green broad leaf weeds will be the most

difficult material through which grain separation can occur. Coupling

these two ideas, a crop such as oats with green broad leaf weeds would

give the most difficult separation problems and would be a good material

to test separation capacity of a new combine design.

More values of crop coefficients are needed to apply prediction

equation to other crops, therefore it is recommended that crop

coefficients be evaluated for other crops not considered in this research

or previously published. This being a laboratory experiment, it is also

reconmiended that further field research be conducted to provide final

verification of the separation model. Because threshing in the cylinder

of either a cross flow or axial flow type of combine affects the

beginning of separation, it is recommended that a computer model be

developed to integrate threshing and separation. This could quickly

evaluate the outcome of different combine design concepts. This model

would be useful in teaching both design and management ideas to students

as well as providing a quick way to check the performace on new designs.

Finally, as a spin-off of the combine separation problem, a procedure

was suggested to evaluate the amount of seed, fertilizer, or other

granular material that would reach the soil through different types and

amounts of residue cover. This has direct application to conservation

tillage conditions and should be evaluated further with field research.

40

As a final summary, it was concluded that grain size and straw type

were two important crop variables affecting separation. Even though the

apparatus did not duplicate true walker motion, the research verified the

effects of grain and straw types on separation. By verifying the cause

and effect relationship, the effect of grain size and straw type on

separation can be applied to a cylinder and concave system as well as a

straw walker. Finally, it was concluded that the separation model by

Gregory and Fedler (1987) does adequately describe the affects of

material properties on grain separation in combines.

REFERENCES

Arnold, R. E. Experiments with rasp bar threshing drum I: Some factors affecting performance. J. agric. Engng Res., 9(2): 99-131, 1964.

Arnold, R. E. and Lake, J. R. Experiments with rasp bar threshing drum II: Comparison of open and closed concaves. J. agric. Engng Res., 9(2): 250-251, 1964.

Baader, W., Sonnenberg, H. and Peters, H. Die entmischung eines komgutfasergut-haufwerkes auf einer vertikal schwingenden, horizontalen unterlage. Grundl. Landtechn. Bd. 19(5): 149-157, 1969.

Boyce, B. H., Pringle, R. T. and Wills, B. M. D. The separation characteristics of a combine harvester and a comparison of straw walker performace. J. agric. Engng Res., 19: 77-84, 1974.

Buchanan, J. D. and Johnson, W. H. Functional characteristics and analysis of a centrifugal threshing and separation mechanism. Transactions of the ASAE. 7: 460-463, 1965.

Fundamentals of machine operation: Combine harvesting. Moline, IL: John Deere service publications, 1973.

Gasparetto, Ettore, Zen, Marcello and Guadagnin, Antonio. Ultra-high speed movie observation of a conventional threshing mechanism (cylinder-concave-rear beater working on wheat). Proceedings of the first international grain and forage conference ASAE, St. Joseph, MI 49085. p 104-111, 1977

Gerb, B. W. Percent soil cover by six vegetative mulches. Agronomy J. 59(6): 610-611, 1967.

Goss, J. R., Kepner, R. A. and Jones, L. G. Performance charact--eristics of the grain combine in barley. Agricultural Engineering. 39(11): 697-702, 1958.

Gregory, J. M. Soil cover prediction with various amounts and types of crop residue. Transactions of the ASAE. 25(5): 1333-1337, 1982.

Gregory, J. M. and Fedler, C. B. Mathematical relationship predicting grain separation in combines. Paper presented at winter meeting ASAE, Chicago, IL. Paper No. 86-1522, 1986.

Gregory, J. M. and Fedler, C. B. Model evaluation and research verification (MERV). Unpublished Paper presented at winter ASAE conference, San Luis Obispo, CA. 1986.

41

42

Gregory, J. M. and Fedler, C. B. Mathematical relationship predicting grain separation in combines. Unpublished paper. Texas Tech University, Lubbock, Tx 79409. 1987.

Huisman, W. Moisture content, coefficient of friction and modulus of elasticity of straw in relation to walker losses in a combine harvester. Proceedings of the first international grain and forage conference ASAE, St. Joseph, MI 49085. p 49-54, 1977.

Jan, E. Z., Zoerb, G. C., Reed, W. B. and Bigsby, F. W. Separation of grain-straw mixture with a rotating perforated drum. Paper presented at winter meeting ASAE, Chicago, IL. Paper No. 74-1582, 1974.

Kepner, R. A., Bainer, Roy. and Barger, E. L. Principles of Farm Machinery. 3'"<* ed, AVI publishing company Inc, West port. Connect icut. 1982.

Lamp, B. J., Jr and Buchele, W. F. Centrifugal threshing of small grains. Transactions of the ASAE. 3(2): 24-28, 1960.

Long, J. D., Hamdy, M. Y. and Johnson, W. H. Centrifugal force and wheat separation. Agricultural Engineering. 50(10): 578-580, 1969.

Mohsenin, N. N. Physical Properties of Plant and Animal Materials. Gordon and Breach Science Publisher's Inc. New York. 1986.

Nyborg, E. 0., McColly, H. F. and Hinkle, R. T. Grain-combine loss characteristics. Transactions of the ASAE. 12(6): 727-732, 1969.

Reed, W. B. and Zoerb, G. C. A laboratory study of straw walker efficiency. Paper presented at winter meeting ASAE, Chicago, IL. Paper No. 72-638, 1972.

Reed, W. B., Zoerb, G. C. and Bigsby, F. W. A laboratory study of grain-straw separation. Transactions of the ASAE. 17(3): 453-460, 1974.

Srivastava, A. K., Hamdy, M. Y., Nelson, G. L., Roller, W. L. and Huber, S. G. Centrifugal grain-straw separation: Part I-theoritical analysis. Transactions of the ASAE. (2): 198-201, 1974.

Stephens, L. E. and Rabe, D. L. Crop properties data for harvesting research. Proceedings of the first international grain and forage conference ASAE, St. Joseph, MI 49085. p 32-33, 1977.

43

Wang, G., Zoerb, G. C. and Bigsby, F. W. A new concept in combine separation analysis. Paper presented at winter meeting ASAE, Chicago, IL. Paper No. 85-1576, 1985.

Wrubleski, P. D. and Smith, L. G. Separation characteristics of conventional and non-conventional grain combines. Tansactions of the ASAE. 23(3): 530-534, 1980.

APPENDIX

44

4 5

Straw Tvpe !Hheat 5" 340 gis Brain Type rCorn 1000 QIS

INPUT DATA

TiM (sec) Tr 1 Tr 2 Tr 3 Tr 4 Tr 5

3 10 10 10 10 10 10 60

16 111 212 303 343 376 398 510

34 184 324 407 461 531 588 722

45 156 221 280 334 380 429 625

12 49 84 125 157 206 265 509

26 108 184 277 355 425 478 661

RESULTS

i«e

3 10 10 10 10 10 10 60

Grains Collected

26.60 95.00 83.40 73.40 51.60 53.60 48.00 173.80

Static Resistance 1000 Oynatic Resistance 394.6

4 6

StraM Type :Wheat 3* 340 gis Brain Type :Blackeye peas 1000 gii

Tile (sec)

3 10 10 10 10 10 10 60

Tr 1

38 204 317 429 503 560 610 703

INPUT DATA

Tr 2

59 323 485 596 656 692 710 783

Tr 3

71 298 422 534 603 644 682 760

Tr 4

52 223 355 435 510 564 609 707

Ir :

59 271 449 573 646 704 740 824

RESULTS

Tiie

3 10 10 10 10 10 10 60

Static Resistance 1000

Srains Collected

55.80 208.00 141.80 107.80 70.20 49.20 37.40 85.20

Dynaiic Resistance 244.6

4 7

StraM Type :Hheat 3' 340 gis 6rain Type iCottonitid 1000 gti

INPUT DATA

Tiie Isec) Tr 1 Tr 2 Tr 3 Tr 4 Tr 5

3 10 10 10 10 10

43 189 323 435 521 578

47 290 428 524 601 658

42 204 293 388 459 525

43 187 289 378 453 504

40 183 277 352 431 477

10 60

625 693 581 553 777

517 790 723 668 646

RESULTS

Tiae

3 10 10 10 10 10 10 60

Static Resistance 1000

Grains Collected

43.00 167.60 111.40 93.40 77.60 55.40 45.40 127.00

Dynaiic Resistar

4 8

StrtN Typt iMhfit 3* 340 qii Sriin Type iBorghui 1000 gis

INPUT DATA

Tiie (sec) Tr 1 Tr 2 Tr 3 Tr 4 Tr 5

3 10 10 10 10 10 10

353 801 890 911 920 927 932

297 756 861 897 912 920 924

241 679 790 841 870 889 901

278 724 829 868 887 899 910

330 774 864 897 916 927 935

60 946 942 929 934 957

RESULTS

Tiie

3 10 10 10 10 10 10 60

ic Resistance 1000

Srains Collected

299.80 447.00 100.00 36.00 18.20 11.40 8.00 21.20

Dynaiic Resistan 58.4

4 9

StraM Type iMheat 3" 340 gis Briin Type iBirdteed 1000 gis

Tiie (sec)

3 10 10 10 10 10 10 60

Tr 1

457 538 544 547 548 549 550 553

INPUT DATA

Tr 2

500 590 596 598 600 601 602 604

Tr 3

656 773 779 781 783 784 785 788

Tr 4

630 731 738 740 742 743 744 748

Tr 5

690 807 813 815 817 819 820 823

RESULTS

Static

Tiie

0

10 10 10 10 10 10 60

istance 716

Sraii ns Collected

586.60 101.20 6.20 2.20 1.80 1.20 1.00 3.00

Dynaiic Resistance 12.8

5 0

StraM Type :Sorghui 3' 360 gis Grain Type iCorn 1000 gis *°---BSaS8aSS8SaBS333SSSBSSS8aBSSBSSS3SSSBSSSSSSSS8SSSS8SSSSSBS8SBSS:

Tiie (sec)

3 10 10 10 10 10 10 60

Tr I

351 498 512 520 523 525 526 534

INPUT DATA

Tr 2

395 599 611 619 623 625 627 632

Tr 3

431 618 633 641 647 650 652 657

Tr 4

350 507 513 520 522 525 527 534

Tr :

331 479 491 498 503 508 510 518

RESULTS

Tiie

3 10 10 10 10 10 10 60

Static Resistance 624.4

Grains Collected

371.60 168.60 11.80 7.60 4.00 3.00 1.80 6.60

Dynaiic Resistan 49.4

5 1

StriH Type iSorghui 3" 360 qii 6rain Typi iBiackeyi peat 1000 gii

INPUT DATA

Tiie (sec) Tr 1 Tr 2 Tr 3 Tr 4 Tr 5

3 285 227 251 234 312 10 10 10 10 10 10 60

376 392 401 406 409 412 420

369 394 405 410 416 418 429

338 361 371 376 378 381 388

317 330 336 340 343 346 355

382 398 40? 412 415 417 425

RESULTS

Tiie

3 10 10 10 10 10 10 60

Static Resistance 485.4

Grains Collected

261.80 94.60 18.60 9.00 4.80 3.40 2.60 8.60

Dynaiic Resistance 82

5 2

8triM lypi iSorghui 3" 360 gii Brain Type iCottonseed 1000 gas

Tiie (sec)

3 10 10 10 10 10

Tr 1

368 542 564 575 581 584

INPUT DATA

Tr 2

388 535 564 573 578 581

Tr 3

385 585 607 620 627 631

Tr 4

396 556 574 583 589 594

Tr ;

367 553 572 580 587 592

10 587 585 633 598 595 60 601 594 644 609 604

RESULTS

Tiie

3 10 10 10 10 10 10 60

ic Resistance 669.6

Grains Collected

380.80 173.40 22.00 10.00 6.20 4.00 3.20 10.80

Dynaiic Resistance 59.2

5 3

StraM Type sSorghui 3" 360 gis Grain Type iBirdiitd 1000 git

Tiie (sec)

3 10 10 10 10 10 10 60

Tr 1

140 175 179 181 182 184 184 187

INPUT DATA

Ir 2

158 191 196 199 200 201 202 205

Tr 3

129 168 174 177 178 179 179 182

Tr 4

146 176 181 183 184 185 186 189

fr !

118 143 147 149 150 151 152 154

RESULTS

Tiie

3 10 10 10 10 10 10 60

Static Resistance 208.4

Grains Collected

138.20 32.40 4.80 2.40 1.00 1.20 0.60 2.80

Dynaiic Resistar 25

5 4

Straw Type :Sorghua 3" 360 gis Grain Type :Sorghui 1000 gis

INPUT DATA

Tiie (sec) Tr 1 Tr 2 Tr 3 Tr 4 Ir 5

60

330

494

326 284

481 388

283

410

326 10 10 10 10 10 10

456 474 480 484 487 488

443 457 465 469 472 473

355 366 371 375 378 380

374 387 393 398 401 404

450 466 474 477 479 481 488

RESULTS

fine

3 10 10 10 10 10 10 60

ic Resistance 495

Grains Collected

309.80 105.80 14.40 6.60 4.00 2.80 1.80 7.00

Dynaiic Resistan 42. B

5 5

Straw Type :Soybean 3* 350 git 6riin Type iCorn 1000 git :ass

Tiie (sec)

3 10 10 10 10 10 10 60

Tr 1

374 641 689 708 719 724 729 752

INPUT DATA

Tr 2

466 706 749 769 777 784 791 811

Tr 3

378 688 736 754 760 766 773 791

Tr 4

372 646 690 711 728 739 743 763

Tr f

464 665 703 725 730 734 738 751

RESULTS

Tiie

3 10 10 10 10 10 10 60

Static Resistance 929

Grains Collected

410.80 258.40 44.20 20.00 9.40 6.60 5.40 18.80

Dynaiic Resistance 155.4

5 6

StraM Type iSoybean 3* 350 git Griin Typi iBUckiye p»i§ 1000 gii

INPUT DATA

Tiie (sec) Tr 1 Tr 2 Tr 3 Tr 4 Tr 5

3 10 10 10 10 10 10 60

333 576 645 679 694 702 710 737

332 669 721 751 767 773 778 800

407 663 725 754 769 778 785 804

300 631 677 698 716 727 733 758

429 705 745 766 782 790 795 820

RESULTS

Tiie

3 10 10 10 10 10 10 60

Static Resistance 942

Grains Collected

360.20 288.60 53.80 27.00 16.00 8.40 6.20 23.60

Dynaiic Resistance 158.2

5 7

Straw Type iSoybean 3" 350 qis Grain Type iCottonieed 1000 gas

Tiie (sec)

3 10 10 10 10 10 10

Tr 1

299 702 789 816 829 636 845

INPUT DATA

Tr 2

428 747 784 796 804 809 817

Tr 3

421 776 812 829 841 848 852

Tr 4

308 726 810 830 839 843 848

Tr !

358 729 790 812 824 833 839

60 863 831 869 863 862

RESULTS

Tiie

3 10 10 10 10 10 10 60

Static Resistance 954.2

Grains Collected

362.80 373.20 61.00 19.60 10.80 6.40 6.40 17.40

Dynaiic Resistance 96.6

5 8

StriM Type iSoybean 3' 350 gis Grain Type iSorghui 1000 gis S S 8 S a S S S 8 3 S S S S S S S S S S S S S 3 S S S X 8 S S 3 a 8 S 8 a a 8 8 B S a Z 8 8 a S 8 S 3 3 8 g

INPUT DATA

Tiie (sec) Tr 1 Tr 2 Tr 3 Tr 4 Tr 5

3 10 10 10 10 10 10 60

332 406 416 421 423 425 426 431

295 395 403 408 411 413 414 419

346 436 448 453 456 458 460 464

346 416 426 431 434 436 437 443

349 425 435 439 441 442 443 447

RESULTS

Tiie

3 10 10 10 10 10 10 60

Grains Collected

333.60 82.00 10.00 4.80 2.60 1.80 1.20 4.80

Static Resistance 467.8 Dynaiic Resistance 27

5 9

StraM Type iSoybean 3' 350 git Grain Type iBirdieed iOoo fit

Tiie (sec)

3 10 10 10 10 10 10 60

Tr 1

90 111 115 117 118 119 119 121

INPUT DATA

Tr 2

77 91 94 95 96 97 97 101

Tr 3

94 108 112 114 115 116 116 119

Tr 4

84 103 107 109 110 110 111 113

Tr !

112 131 135 137 138 139 139 142

RESULTS

Tiie

3 10 10 li) 10 10 10 60

Static Resistance 140

Grains Collected

91.40 17.40 3.80 1.80 1.00 0.80 0.20 2.80

Dynaiic Resistance 20.8

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