UNIVERSITY OF IBADAN LIBRARY
2
humid climates, daily temperature fluctuation could be as much as 15°C for most part of the
year. The use of metal silos with high thermal conductivities of as much as 250W ImoK for
aluminum and 62W/moK for steel (Parrish, 1973), results in moisture condensation on the
inner walls and roof of the' silo and its redistribution within 'the bulk grain. This situation
results in the development of hot spots, grain dampness, mould growth, grain germination and
rapid multiplication of insects in the event of infestation. Salty water in coastal areas corrodes
the material besides the spoilage of the stored grains (Igbeka, 1983; Birewar, 1990; Talabi,
1996; Adesuyi, 1997). The twin problems of moisture condensation under a warm and humid
environment such as in Nigeria and the prohibitive cost of the imported metal silos, limit their
availability to a majority of farmers who may need to store their surpluses.
While some researchers have attempted to modify the metal silos to suit the local
environment, others have advocated the use of local materials of construction. Advocates of
local materials for grain silo construction opine that small sized silos could be produced to
meet farmers' needs and at cheaper rates. With these, there will be savings in foreign reserve
since the level of importation will reduce and local expertise in silo design and construction
will be promoted.
Concrete plays a prominent role in silo construction both as wall and foundation. It is
resistant to corrosion from inorganic acids. Single-walled mass concrete silos or those of
blocks have been tested and found to reduce the severity of moisture condensation while
those of double walls constructed from concrete staves and incorporating an air-space
completely eliminated the problem of moisture condensation (Osobu, 1971; Lasisi, 1975).
Concrete is however weak in tension and if used, must be reinforced with steel rods or
welded mesh to withstand the lateral pressures due to the stored materials. Construction
labour is high while it is also prone to rise in ground moisture and grains directly in contact
with the floor may be damaged from moisture (Osunade, 1991). Laterized concrete silo made
from a mixture of laterite soil, cement and gravel has also been developed (Osunade, 2000).
Rubber silos are most unsuitable for use under the warm humid climate as the material suffers
severe moisture condensation under intense heat. It is prone to weathering from intense heat
of the sun while it is also easily attacked by rodents. Little cracks soon graduate to large holes
resulting in severe produce losses.
The low thermal conductivity of wood products of about 0.12 Wlm oK (parrish, 1973) and
their availability most especially in Southwestern Nigeria encouraged their consideration for
use in silo construction. Mijinyawa (1989), Alabadan (2002) and Alabadan (2006)
investigated the potentials of wooden silos in reducing temperature fluctuations. They found
that temperature fluctuations obtained within the wooden silos were lower than for those in
metal silos. The susceptibility of wood to biodeterioration and difficulty of making the joints
tight in order to eliminate crevices where insects could hibernate were some of its
disadvantages. Termites build their tunnels from the soil into the wooden structures leaving
the surface untouched which makes it difficult to detect an attack in the early stages (John et
al.,1995).
Mijinyawa, Y; E.B. Lucas and F.O. Adegunloye. "Termite Mound Clay as Material for Grain
Silo Construction". Agricultural Engineering International: the CIGR Ejournal. Manuscript
BC 07002. Vol. IX. July, 2007
UNIVERSITY OF IBADAN LIBRARY
3
The use of clay in the construction of crop storage structures dates back to 1915, when a
round barn or silo was constructed with hollow clay tiles at the Slatyon farm in Iowa, United
States (Iowa FHPC, 2003). Different types of clay constructed structures are in present use in
various parts of the world. These include the native rhumbu, the laterite - impregnated grass
structure and the dried earth granaries in Northern Nigeria while the pusa bin is common in
India. The major advantage of the native rhumbu is its ability to provide a cool environment
for storage. This is attributed to the low thermal conductivity of about 1.1SW/moK which is
lower than that of concrete and metal silos (Osunade and Lasisi, 1998). Domestic grain
storage especially those for use as seeds, is done in hermetic clay pots.The kachia kothi is a
crop storage structure manufactured from clay and popularly used in Asia. Other types
include the Mexican store which is a closed clay silo in curved walls that is difficult for rats
to gain access.
1.1 Definition and Properties of Clay
Although a number of authors such as Cooper (1991) and Morris (1997) have given different
definitions, clay can be defined as a very fine-grained soil of less than O.lmm in size and
which is plastic when moist but hard when fired .The plastic nature under wet condition
enables clay to be moulded into any shape which is retained upon drying. Good clay should
therefore exhibit this plastic property. The suitability of any clay for moulding can be tested
through moulding about 200mm coil (about the size of a finger) on a slab.lf the coil cracks in
the outer edges, the clay is probably less plastic. If on the other hand, the coil does not crack
in the outer edges, the clay has adequate plasticity and is a good material for moulding
(Daniel, 1977). When used in construction, clay often undergoes some treatments which
improve the properties. When used as bricks, clay is subjected to a temperature of as much as
500°C or even higher. During this process, the alumina content in the clay melts thus raising
the burning temperature to about 27SoC which is much higher than temperatures experienced
in fire accidents. This is why clay products possess excellent fire re_sistant properties
compared to wood (Hall and Jackman, 1975; Lucas and Fuwape, 1984; Schaffer, 1988;
Schaffer, 1992; FPL,1974; Hendry et at, 1987). Parker (1998) reported that besides the
improvement in fire resistance, the elevated temperatures also improve the resistance to
moisture penetration.
The pile of earth made by termites resembling a small hill is called a termite mound. It is
made of clay whose plasticity has further been improved by the secretion from the termite
while being used in building the mound. It is therefore a better material than the ordinary clay
in terms of utilization for moulding (Odumodu, 1991). This type of clay has been reported to
perform better than ordinary clay in dam construction (Yohanna et at, 2003). The clay from
termite mound is capable of maintaining a permanent shape after moulding Termite mound
clay is being considered for use in silo construction because of its plasticity and less prone to
crack when compared with ordinary clay. Heat treated termite mound clay units are resistant
to wear, abrasion and penetration by liquids (Parker, 1998). Termite mound clay has low
thermal conductivity and expectedly should reduce solar heat flow into the silo enclosure and
regulate temperature fluctuations within the storage environment.
Mijinyawa, Y; E.B. Lucas and F.O. Adegunloye. "Termite Mound Clay as Material for Grain
Silo Construction". Agricultural Engineering International: the CIGR Ejournal. Manuscript
BC 07 002. Vol. IX. July, 2007
UNIVERSITY OF IBADAN LIBRARY
4
The objective of the work reported in this paper was to develop a durable, efficient,
affordable and cost effective silo that could be sited on locations close to the small scale
farmers to store their grains:
2. MATERIALS AND METHODS
The materials and methods were divided into three parts: design, construction and testing of
the silo prototype.
2.1.0 Design
2.1.1 Design Considerations
In the design of the silo, a number of factors aimed at ensuring effective utilization, ease of
construction and management, considering the level of technology available in the rural
communities and accessibility to the intended beneficiaries were taken into account.
Information obtained from the extension unit of the Ondo State Agricultural Development
Project (Ondo State ADP, 2005), puts the annual grain production per farmer at 4 tonnes and
this value was used as the capacity for the silo. It is noted that some farmers may not produce
up to this capacity while those who produce as much may not store all the harvests but the
choice of this capacity is to make provision for future expansion. Maize is the most common
grain cultivated in the area where this study was undertaken and its properties were used in
the design.
2.1.2 Silo Shape and Dimensions:
In order to minimize areas of stress concentrations, a cylindrical shape was chosen and for the
estimated capacity of 4 tonnes using shelled corn of a density nOkg/m3 and angle of repose
of 27° , an internal diameter of 2.0 m and height of 1.8 m were considered adequate for the
silo.
2.1.3 Pressure Analysis
The ratio of the depth - to - diameter shows that the silo is a shallow type. The basic
difference between a deep and a shallow silo is the presence of wall friction in a deep silo and
its absence in a shallow one. Gurfinkel (1979) reported that even in the deep silos where the
wall friction initially exists, it disappears after sometime as a result of the deposition of wax-
like materials on the wall surface from the grains and the wall becomes smooth taking the
form of a shallow silo. The silo was therefore designed as a shallow one using the Rankine
approach reported by Gaylord and Gaylord (1984). The design therefore assumed only the
presence of lateral and floor pressures due to the stored grains. These were calculated from
the following equations
L = wy( I - si.n0 J = wy tan 2 (45 - ( ) Equation 1
1+ sin e' 2
Mijinyawa, Y; E.B. Lucas and F.O. Adegunloye. "Termite Mound Clay as Material for Grain
Silo Construction". Agricultural Engineering International: the CIGR Ejournal. Manuscript
BC 07 002. Vol. IX. July, 2007
UNIVERSITY OF IBADAN LIBRARY
5
F, = w.h Equation 2
where
L = lateral pressure per unit of wall area, N/m2
w = unit weight of the stored material, N/m3 .
y = distance from the top surface of grain to the point within the grain at which the pressure is
considered, m
f) = angle of repose of the stored material, degrees
h = height of grain above the floor, m
F, = floor pressure due to grains, N/m2
The maximum lateral pressure was calculated to be 5.8kN/m2 while the floor pressure was
12.7kN/m2. A factor of safety of 1.4 was used to take into account dynamic loads that may be
developed during unloading. The design loads were obtained as 8.1kN/m2 for the lateral
pressure and 17.8kN/m2 for the floor.
2.1.4 Silo Wall Thickness
A number of empirical formulae are available for the estimation of wall thickness of small
capacity silos constructed from clay. Some of these are the FAO (1987) method given by
t = -R-~ .t, Equation 3
where t, is the wall thickness in m, R is the internal radius of the silo in m, Ph is the maximum
lateral pressure in N/m2 due to the stored grains and T, is the maximum tensile strength in kN/m2
of the wall material. For dry clay soil, T, is 30 - 60 kN/m2. (FAO, 1987)
The Ghali (1979) method is given by the following equation
t = ~ Equation 4
15
where t is the wall thickness in meters, and h is the wall height in meters
Bengtsson and Whitaker (1986) gave the following equation
t = D + 12 ~ Equation 5
where t is the wall thickness in centimeters and D is the silo diameter in meters.
The silo wall thickness was calculated using each of the three approaches. The values
obtained were 13.5 em, 12 cm and 14 em for the FAO (1987), Ghali (1979) and Bengtsson and
Whitaker (1986) methods respectively. A wall thickness of 15 cm was selected. This dimension
will be adequate to take care of any shrinkage on drying.
2.1.5 Number of Bricks Required
Mijinyawa, Y; E.B. Lucas and F.O. Adegunloye. "Termite Mound Clay as Material for Grain
Silo Construction". Agricultural Engineering International: the CIGR Ejournal. Manuscript
BC 07 002. Vol. IX. July, 2007
UNIVERSITY OF IBADAN LIBRARY
6
In estimating the number of clay bricks that would be required for the silo wall, the
circumference and height of the wall, brick dimensions and thickness of the binding mortar were
taken into account. Openings on the wall such as the unloading chute were ignored. The
following formula was used
N - (Lb + 27!RHm )(hb + m ) •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• Equation 6
l l
where R is the external radius of the silo, m
H is the height of the silo, m
Lband hb are the length and height of the bricks, m
rn, is mortar thickness, m.
The dimensions of the bricks were 0.215 x 0.150 x 0.065 m and a mortar thickness of 0.012 m
was assumed. The number of bricks was calculated as follows
2(3.142)(1.15)(1.8)
N = 745
(0.215 + 0.012)(0.065 + 0.012)
In order to cater for breakages during construction and preparation of the mix to be used as
mortar, 900 units were recommended.
2.1.6 Design against Wind Load
Besides grains, wind is another factor that imposes loads on a silo and which must be considered.
A number of empirical formulae are available for predicting this but the modified formula of
Barre and Sammet (1966) given as follows was used
P = 0.05C A y2 . . Equation 7
where
P = the load due to wind imposed on the silo, N
C = pressure coefficient which takes into account the orientation of the structure to main wind
direction and is usually taken as 0.8 for cylindrical silos
A = projected area of the structure, m2
y = wind velocity in the environment, km/hr
Using a wind speed of 112 krn/hr for the silo location (NCP, 1973) and a projected area of 4 m2,
the overturning moment was calculated as 1.98 kN-m.The resisting moment due to the self
weight of the silo was calculated as 237 kN-m which far exceeded the overturning moment. This
shows that even if the silo was only placed on the ground without any anchorage, there would be
no overturning. In practice, the silo will not only be anchored but the stored materials will
increase the value of the resisting moment. The silo is therefore of adequate stability against wind
load.
2.2.0 Construction
Mijinyawa, Y; E.B. Lucas and F.O. Adegunloye. "Termite Mound Clay as Material for Grain
Silo Construction". Agricultural Engineering International: the CIGR Ejoumal. Manuscript
BC 07 002. Yol. IX. July, 2007
UNIVERSITY OF IBADAN LIBRARY
7
The silo construction comprised of the collection of clay and brick making, and the construction
of the foundation, the wall, the roof and the accessories.
2.2.1 Clay Collection and Brick Making
In order to be able to obtain clay from the mounds, the termites were evacuated through the
application of chemical powder (pestox) into the broken mounds and the surroundings. The
lumps of termite mound clay were then collected and deposited at a clean site. Size reduction of
the clay lumps was achieved through pounding with pestle. The clay was then mixed with water
in the ratio of two volumes of termite mound to one volume of water. The wet clay was then
poured into a 215 x 150 x 65 mm wooden mould placed in a manually operated moulding
machine and vibrated to ensure compaction and appropriate shape forming. The bricks were then
removed and left for five days to dry naturally. They were thereafter burned in a mud-kiln with
the use of firewood as the source of heat (Figure1). The kiln temperature was about 500°C
monitored with a thermocouple.
Figure 1: Dried termite mound bricks being Figure 2: Veneers and iron rods used to mark
set for burning in amud-kiln the circular foundation
2.2.2 Construction of the Foundation
In order to define the perimeter of the silo foundation, the two ends of a 1300 mm long binding
wire were tied to 30 em long iron rods. One of the rods was placed at the proposed centre of the
silo while the other was used to draw a circle defining the outer radius of the silo. The foundation
was excavated and the footing cast. Strips of 30 cm height were obtained from 3 mm thick veneer
and bent to form the inner and outer circumferences of the foundation and supported at intervals
with iron rod pegs (Figure 2). Stones were then used to construct the foundation. The foundation
was filled with laterite after which a concrete floor of 1:3:5 mix and 40 mm thickness was
constructed. The floor was slopped at 8° towards the discharge chute in order to aid grain
discharge. Figure 3.
Mijinyawa, Y; E.B. Lucas and F.O. Adegunloye. "Termite Mound Clay as Material for Grain
Silo Construction". Agricultural Engineering International: the CIGR Ejournal. Manuscript
Be 07 002. Vol. IX. July, 2007
UNIVERSITY O
 IBADAN LIBRARY
8
Figure 3 Round concrete floor on stone Figure 4: Setting of bricks in progress
foundation
2.2.3 Setting and Laying of Bricks on the Wall
Because of the concrete floor cast over the foundation, it was necessary to redefine the silo
circumference so that the wall could be correctly positioned. This was re-established using the
binding wire and rods.The bricks were then set in layers using slip clay and grog as the mortar.
This was progressively done till the required height was reached, (Figure 4). Allowances were
made for the locations of the manhole and the discharge chute.
2.2.4 The Roof
The shape of the roof was conical with the circular base resting on the silo top. The wall plate
made of 75mm x 100mm timber was secured onto the wall top using metal bands. Roof joists of
50mm x 100mm were securely nailed on the wall plate and across the circular surface with 75mm
long wire nails.The roof was extended below the top of the wall to provide 300 mm overhang.
The truss was covered with corrugated iron sheets and asbestos-cement sheets used as ceiling
Figure 5.
Figure 6: Loading chute attached to the roof truss
Figure 5: Completed roof truss
of the silo
2.2.5 Accessories
Mijinyawa, Y; E.B. Lucas and F.O. Adegunloye. "Termite Mound Clay as Material for Grain
Silo Construction". Agricultural Engineering International: the CIGR Ejournal. Manuscript
BC 07 002. Vol. IX. July, 2007
UNIVERSITY OF IBADAN LIBRARY
9
The silo accessories were the loading and discharge chutes, and the manhole for inspection. The
loading chute comprised of a trapezoidal wooden frame of 400 mm x 300 mm and height of 300
mm and attached to the roof truss (Figure 6). The chute was covered with a removable roofing
sheet with the hinge points provided with rubber gaskets to eliminate moisture entry into the silo.
The manhole provided entry into the silo to carry out any necessary repairs and cleaning. This
was located on the wall towards the base and measured 560 mm x 480 mm. The discharge chute
of dimensions 160 mm x 150 mm formed part of the manhole. Loading was accomplished with
the use of a ladder which was only in place when loading was to be done. The completed silo is
shown in Figure 7.
Figure 7: Completed silo showing
the manhole to which the
discharge chute is attached
2.2.6 Precautionary Measures
In order to protect the silo structure and the contents, a number of precautionary measures were
taken into account in its design and construction. Some of these precautions included the
followings
i) An eave of about 30 cm was provided to prevent the entry of rainwater into the silo and to
move away the drop line from the base of the silo so that splashing rain did not erode the
foundation and wall. The roof pitch of 34.9° ensured adequate roof drainage and prevented
ponding.The concrete floor supported on a stone base foundation prevented flooding and
moisture capillary action. The silo site had adequate drainage.
ii) Both sides of the silo wall were smooth which prevented insect hibernation inside and made it
difficult for rodents to climb outside. The eave was sealed making it impossible for rodents, birds
lizards and insects to gain access to the silo. The walls and floor were thick and strong enough to
resist burrowing by rodents. The surroundings of the silo were well cleaned of vegetation and
debris that could either harbour rodents or attract insects.
2.3 . 0 Testing
Mijinyawa, Y; E.B. Lucas and F.O. Adegunloye. "Termite Mound Clay as Material for Grain
Silo Construction". Agricultural Engineering International: the CIGR Ejournal. Manuscript
BC 07 002. Vol. IX. July, 2007
UNIVERSITY OF IBADAN LIBRARY
10
Three tests were carried out in order to establish the efficacy of the silo. These were temperatures
measurements, grain quality monitoring and viability test of stored .grains.
2.3.1 Temperature Monitoring
One of the arguments in favour of using the termite mound clay for the silo construction is that in
view of its low thermal conductivity, it should be able to reduce temperature fluctuations within
the silo. This was why the measurement of temperature fluctuations inside and outside the silo
was carried out. The temperature fluctuations inside the silo and the environment where it was
located over a period of 24hrs were measured by placing combined maximum and minimum
thermometers inside and outside the silo for a period of 60 days. Temperatures readings were
taken three times daily at 06:00 h, 12:00 hand 18:00 h.
2.3.2 Grain Quality Monitoring
One tonne of maize was purchased from the open market in Ondo , cleaned and dried, and
samples were taken for test. The samples were manually sorted into foreign matters, moulded
grains, broken grain and infested grain. The percentage of each of the groups present in the
sample was calculated as follows
p = .................................................................................. Equation 8
where
p = % of sample that belongs to the particular group.
Wi = Weight of the sample that belongs to the particular group.
Wt = Total weight of the sample
The moisture content of the maize was determined using a digital moisture meter. The results
were compared with the specification set by the Strategic Grains Reserve Scheme for grains
meant for storage in silos (Table 1) to ensure minimum standard before storage. The grain was
then loaded into the silo and left for a period of sixty days.At the end of the test period, the grain
was unloaded and the same analyses were carried out.
r
Mijinyawa, Y; E.B. Lucas and F.O. Adegunloye. "Termite Mound Clay as Material for Grain
Silo Construction". Agricultural Engineering International: the CIGR Ejournal. Manuscript
BC 07 002. Vol. IX. July, 2007
UNIVERSITY OF IBADAN LIBRARY
11
Table 1: Specification for Grains to be Stored in a Silo
Parameter Maximum value
Moisture content (%) 12.0
Test weight/hectoliter weight 68 - 7SKg/hl
Broken grains (sorghum, soyabean, cowpea 1%
and maize)
Damaged grain due to insects 1%
Damaged grain due to mould 1%
Foreign matter 1%
Grain age 1 year
Source: National Strategic Grain Reserve Scheme, Akure Station, (200S)
2.3.3 Viability Test
Stored grains are often required for use as seeds and it was considered necessary that viability
should be one of the indices of measuring the efficacy of the silo. Pre - and post-storage viability
tests were therefore carried out using the method suggested by Ellis (1988). The result was
calculated from the formula
WONg
V = Equation 9
Nt
v = viability in %
Ng = Number of seeds that germinated
N, = Total number of seeds planted
3. RESULTS AND DISCUSSION
3.1 Temperatures Pattern
The minimum ambient temperature recorded in the morning was 210e while the highest values
were recorded at noon, reaching up to 36°e and expectedly reduced in the evenings. In many
cases, the temperatures remained at ss-c in the evenings. Temperature readings within the silo
were nearly constant at 200e in the mornings and 30°C in the afternoons. Temperature
fluctuation within the silo was slightly more stable than outside with mean daily fluctuations of
9.SoC and 10.3°C respectively. These values are significant because a lower average temperature
fluctuation within the silo compared with a higher ambient average is an indication that the silo
enclosure would store grain at a lower temperature.
3.2 Grain Quality before and after Storage
Mijinyawa, Y; E.B. Lucas and F.O. Adegunloye. "Termite Mound Clay as Material for Grain
Silo Construction". Agricultural Engineering International: the eIGR Ejournal. Manuscript
Be 07002. Vol. IX. July, 2007
UNIVERSITY OF IBADAN LIBRARY
12
The results of the grain quality assessment before and after 60-day storage are presented in Table
2. The initial moisture content of the maize was 12% and after unloading the grains, this value
remained unchanged. This value was recorded despite the occurrence of rainfall for some days
within the storage period. The constant value of the moisture content of maize before and after
storage was a confirmation that the maize neither gained nor lost moisture while in storage. The
grain was not wet and this showed that there were no leakages from the roof and wall of the silo
when it rained. The maize seeds had no insect holes on them and there were no changes in their
texture since none of them was powdery. These observations confirmed that the maize seeds
were not subjected to insect infestation while in storage. The maize shape remained intact as
there were no noticeable changes in the common oblong maize shape. There was no evidence of
rodents attack on the stored maize. Contamination from rodent's faeces was also absent.
3.3 Maize Viability before and after Storage
The pre-storage viability was 88% which fell to 84% after storage. This level is well above 60%
which is the minimum recommended for seeds to be used for planting (Ellis,1988). The silo is
therefore a good store for seeds.
Table 2: Quality of Maize before and after Storage
Parameter Quality of Maize before Storage Quality of Maize after Storage
Foreign material (%) 0.10 0.10
Mouldy grain (%) 0.26 0.28
Broken grain (%) 0.09 0.10
Insect infested(%) 0.03 0.03
Moisture content (%) 12 (dry basis) 12 (dry basis)
Seeds viability (%) 88 84
3.4 Benefits of the Silo
a) At present, there is very little use of the termite mounds which are in abundance in many parts
of Nigeria and especially in the study area. There is assurance of raw material and silos can
readily be made available to farmers.
b) The design is simple and the construction can be readily accomplished locally.
c) While the high unit capacity of silos especially the metal ones was the main attraction for their
use at inception for cooperatve grain storage programmes, the collapse of the cooperatives has
rendered most of the commercial silos including those of the Strategic Grain Reserve Scheme
redundant for lack of grains to store. Small capacity silos such as the one developed in this study
will suit the requirement of the individual farmers and the frequency of use will be high.
Mijinyawa, Y; E.B. Lucas and F.O. Adegunloye. "Termite Mound Clay as Material for Grain
. Silo Construction". Agricultural Engineering International: the CIGR Ejournal. Manuscript
BC 07002. Vol. IX. July, 2007
UNIVERSITY OF IBADAN LIBRARY
13
4. CONCLUSIONS AND RECOMMENDATIONS
A grain silo has been designed, fabricated from treated termite mound clay and tested. The silo
demonstrates some prospects for 'use in grain storage limiting some of the problems experienced
with other materials especially temperature fluctuations and moisture condensation. The
availability of the material of construction and relatively simple construction and management
techniques will make the silo cheap and within the reach of the small scale farmers. Further work
should focus on temperature, relative humidity and moisture content monitoring under full load for
longer storage period. A comparative evaluation of the silo performance with those of other
materials of silos construction should also be undertaken.
5. REFERENCES
Adegunloye, F.O. (2007). Utilisation and Evaluation of Treated Termite Mound Clay Bricks for
Grain Silo Construction., Unpublished PhD thesis. University of Ibadan, Nigeria.
Adesuyi, S. A. (1997). Preservation of Grains in the Tropics with Special Reference to Nigeria.
Applied Tropical Agriculture (2), 50 -56. Federal University of Technology, Akure,
Nigeria.
Alabadan, B. A. (2002). Modelling the Performance of a Hexagonal Wooden Silo During
. Storage of Maize (Zea mays) Unpublished PhD thesis, University of Ibadan, Nigeria,
Alabadan. B.A.(2006). "Evaluation of Wooden Silo during Storage of Maize (Zea mays) in Humid
Tropical Climate". Agricultural Engineering International: the CIGR Ejournal. Manuscript
BC 05 013. Vol. VIII. February, 2006.
Barre, H. J. and L.L. Sammet (1966) Farm Structures. John Wiley & Sons, New York
Bengtsson, L. and J. H. Whitaker (1986). Farm Structures in Tropical Climates. A Textbook for
Structural Engineering and Design FAO, Rome.
Birewar, B. R. (1990). Development of Improved On-farm Grain Drying Facility in Nigeria.
AMA:,27(1) 51~53.
Cooper, E. (1991). A Handbook of Pottery. Longman Publishers, Great Britain.
Daniel, R. (1977). Clay and Glazesfor the Potter. Pitman Publishing, London.
Ellis, R.H. (1988). The Viability Equation, Seed Viability Nomographs, and Practical Advice on
Seed Storage. Seed Science & Technology. 16: 29-50
FAO (1987). Construction and Operation of Small Solid-Wall Bins. Food and Agricultural
Organization of the United Nations. Agricultural Services Bulletin No 69 (Eds) Ole
Bodholt and Aliou Diop.
FPL (1974). Wood Handbook: Wood as an engineering material. Forest Products Laboratory,
U.S. Department of Agriculture Handbook No 72
Gaylord, E. H. and C. N. Gaylord (1984). Design of Steel Bins for Storage of Bulk Solids.
Prentice-Hall International Series in Civil Engineering and Engineering Mechanics.
Prentice-Hall, Inc, New Jersey.
Ghali, A. (1979). Circular Storage Tanks and Silos. E & F.N. Spon Ltd 11, New Fetter Lane,
London.
Mijinyawa, Y; E.B. Lucas and F.O. Adegunloye. "Termite Mound Clay as Material for Grain
Silo Construction". Agricultural Engineering International: the CIGR Ejournal. Manuscript
Be 07002. Vol. IX. July, 2007
UNIVERSITY OF IBADAN LIBRARY
14
Gurfinkel, G. (1979). Reinforced Concrete Bunkers and Silos in Structural Handbook. In (Eds)
E.H. Gaylord and C. N. Gaylord. McGraw - Hill Book Company, New York. 2nd Edition.
Hall, G.S. and Jackman, P.E. (1975). Performance of Timber in Fire.Timber Trades Journal
(Nov.15): 38 - 40. .
Hendry, A. W; Sinha, B. P and S. R. Davies, (1987). Load Bearing Brickwork Design. 2nd
Edition. Ellis Horwood Series in Engineering Science. Ellis Horwood Ltd. England.
Igbeka, J.C. (1983). Evaluation of Grain Storage Techniques in Nigeria. African Journal of
Science and Technology. (AJST) ANSTI-UNESCO, Nairobi 2: 22 - 34.
IOWA. Iowa Falls Historic Preservation Commission (2003). The Slayton Farm Round Barn.
National Register of Historic Places Hardin County, Iowa.
John V.W; Wolfram, P.and H. Fritz (1995). Rural Building Course. IT Publication Ltd.
London.(1) .143 -144.
Lasisi, F., (1975). A Tropical Small Farm Storage Structure for Grains. The Nigerian
Agricultural Journal. 12 (1): 9 - 22
Lucas, E.B and Fuwape, J.A. (1984). Burning and Related Characteristics of Forty-two Nigerian
Fuelwood Tree Species. The Nigerian Journal of Forestry. 14 (l & 2): 45 - 52
Mijinyawa, Y (1989). The Use of Wood Products in the Design and Construction of a Grain Silo
for the Humid Tropics. Unpublished PhD thesis. University of Ibadan, Nigeria
Mijinyawa, Y. (1999). Wood Products for Grain Silo Construction. Journal of
Engineering Applications 1(2): 25 - 29
Morris, C (1997). Academic Press Dictionary of Science and Technology. Academic Press,
Harcourt Brace Jovanovich Publishers, New York.
National Strategic Grain Reserve Scheme, Akure Station, (2005). Specification for grains to be
stored in a silo. Unpublished Laboratory Manual,
Nigerian Standard Code of Practice. NCP 1: 1973 Part 3: Loading. Federal Ministry of
Industries, Lagos.
Odumodu, R. C. (1991). Clay Block Industry in Nigeria, Problem and Prospects. Engineering
Focus 3(6) 37 - 40. NSE Publication, National Engineering Centre, Victorial Island,
Lagos.
Ondo State Agricultural Development Project (2005): Unpublished File Records on Annual
Production ofvarious crops. Ministry of Agriculture, Akure, Nigeria
Osobu, A. (1971). Structural efficiency and Economics of Locally Produced and Imported
structures. A paper presented at the Regional Agricultural Research Seminar co-
sponsored by the Ford Foundation, lITA and IAR&T, Moor Plantation Ibadan.Held at the
University of Ibadan July 26 - 30, 1971.4 pages.
Osunade, J.A and Fola Lasisi (1988). Use of Laterized Concrete Silos for On-the- farm Grain
Storage. Proceedings of the 1988 International Conference of the Nigerian Society of
Engineers, pp 64 - 69.
Osunade, J. A. (1991). Design of Storage Systems I. Technical Paper Presented at a Workshop
on Design, Construction and Maintenance of Food Storage System Organized by the
Nigerian Society of Engineers, Victoria Island, Lagos, Nigeria. 1 - 3 May
Osunade, J.A (2000). Nutritional Quality of Maize Grains Stored in Laterized Concrete Silo.
Journal of Agricultural Engineering and Technology, (2000):8,59 - 64
Parker, P. S. (1998). Structural Design. McGraw Hill Concise Encyclopedia of Science and
Technology 4thEdition, New York.
Mijinyawa, Y; E.B. Lucas and F.O. Adegunloye. "Termite Mound Clay as Material for Grain
Silo Construction". Agricultural Engineering International: the CIGR Ejournal. Manuscript
BC 07002. Vol. IX. July, 2007
UNIVERSITY OF IBADAN LIBRARY
15
Parrish, A. (1973). Mechanical Engineers Reference Book. 11 th Edition. Butterworth and
Company Publishers, London. 2-25
Schaffer, E. (1988). How Well Do Wood Trusses Really Perform During Fire? Fire Journal
82(2): 57 - 63. .
Schaffer, E. (1992). Fire Resistive Structural Design. In Proceedings, International Seminar on
Wood Engineering, University of Denver, Colorado, U.S.A. Pp. 47 - 60. >
Talabi A. E. (1996). Implementation of National Food Security Programme: Experience So Far.
In Proceedings of the National Workshop on Strategic Grains Reserve Storage
Programme. Federal Ministry of Agriculture, Abuja. 26th - 28th July. 1996
Yohanna, lK; A. U. Fulani; E.D. Azagaku and A. D. Anda (2003). Prospects of Using Ant Hill
Materials for the Control of Seepage in Earth Dams. Proceedings of the Nigerian
Institution of Agricultural Engineers (25),135 - 143
Mijinyawa, Y; E.B. Lucas and F.O. Adegunloye. "Termite Mound Clay as Material for Grain
Silo Construction". Agricultural Engineering International: the CIGR Ejournal. Manuscript
BC 07 002. Vol. IX. July, 2007
UNIVERSITY OF IBADAN LIBRARY