26
EDUCATION
tuesday, march 15, 2011
Solar tunnel dryer designed for dates
the upper transparent plastic cover.
The black painted metallic sheets,
which act as solar heat collectors, absorb this heat. As a result the air inside
the tunnel becomes hot particularly in
the collector part of the tunnel. Then
this hot air is forced by a fan from the
collector region (south side) to pass
over the product in the drying region
(north side) of the half circled tunnel.
The product also directly receives
solar radiation in addition to the heat
supply from the collector part of the
tunnel. Thus this dryer is considered
as mixed mode type solar dryer.
Formation damage
around boreholes
during EOR process
Direct experiment
D
ried products are becoming
highly profitable alternative
to marketing than the freshly
harvested products. Annual production of dates in Oman is estimated
at about 200,000 tonnes. Approxi-
colour changes occur and drying becomes slow. Soiling, contamination
with micro-organisms and infection
with disease-causing germs shorten
their shelf-life and damage their quality.
the dryer was analysed in drying about
200 kg of freshly harvested dates in a
batch having initial moisture content
32.8 per cent (wet-basis). It was possible to reach the safe moisture content level for storage within less than
two days (20 hours) with solar tunnel
dryer and 5-7 days in open air natural
sun drying. The results indicated that
the drying was faster in solar tunnel
dryer than the natural open air sun
drying. The improvement in the quality of dates in terms of colour, brightness, flavour, and taste and food value
was distinctly recognised.
Dr Basunia goes on to say that the
drying air temperature could be easo
ily raised to 5-300 C above the ambient temperature while the average
velocity of air flow inside the tunnel
was 0.5 m/s. The temperature can be
o
easily maintained within 40-650 C
inside tunnel which is considered as
appropriate temperature for drying
most of the agricultural products.
Additional income
mately 50 per cent of this production
is used in dried form both for human
and animal consumptions. Dates contribute 12.5 per cent of food energy
consumption in Oman, which is the
3rd largest significant contribution
after wheat and rice.
About 350,500 hectares of land
is under date palm cultivation which
is about 52 per cent of the total cultivable land of Oman. Over eight million palm trees of varied verities are
grown in this cultivable land.
The world production of dates is
about five millions tonnes and Oman
is producing 4-5 per cent of the world
production. A study shows that about
22 per cent of the total dates produced
in Pakistan are wasted every year
due to unavailability of proper drying, processing and storage facilities.
There is no such estimation available
in Oman, but it seems that these losses are much higher in Oman.
Most of the dates, particularly in
the rural areas, are still dried by traditional method of open air natural
sun drying in Oman. This method
of drying normally takes days; between 14 to 21 days in Oman. The
traditional open air natural sun drying methods often yield poor quality.
In most cases the drying yard is not
properly fenced. So the product is not
protected against dust, rain and wind,
or even against insects, birds, rodents
and domestic animals while drying.
In the traditional methods of drying, dew accumulates on the surface
of dates and causes mould growth if it
is not covered properly at night. The
Solar tunnel dryer
In order to solve these problems,
Dr Basunia, Assistant Professor of
the Department of Soils and Water
and Agricultural Engineering, in the
College of Agricultural and Marine
Sciences at SQU, has designed a solar tunnel dryer which will expedite
the drying process and maintain the
high quality of dates.
Dr Basunia says that this novel
solar tunnel dryer was designed and
constructed with locally available
materials at the Department of Soils,
Water and Agricultural Engineering
in the College of Agricultural and
Marine Sciences. The performance of
Dr Basunia explains that an economic analysis shows that a farmer
having 150-200 date trees can easily
earn additional RO 1,000 from the
dried dates instead of selling it as a
freshly harvested product. These investigations show that solar tunnel
dryer can be used for low temperature
drying of dates and other agricultural
products in the rural areas of Oman
where electricity is not available. He
goes on to say that the solar drying
facilities combine the advantages of
traditional and industrial methods,
namely low investment costs and
high product quality. Solar heating
system can improve the quality of the
product, while reducing waste produce and traditional fuels.
Dr Basunia goes on to say that in
order to test the effectiveness of the
dryer it was placed in the open farm
yard of the Agricultural Experimental Station (AES) of Sultan Qaboos
University. The no-load tests with
and without fan were conducted to
know the temperature and air flow
characteristics at different weather
conditions and also, the temperature
gradient both in the collector and dryer regions of the tunnel. The drying
air temperature could be easily raised
o
by some 5-300 C above the ambient
temperature at an air flow rate of 0.51.0 m/sec.
Bigger capacity
The difference between the drying
Dr Basunia believes that this dryer
air
temperature
and ambient temperawill be able to dry more quantities of
dates than the traditional methods. ture gradually increased from morning till mid-day, then gradually fall in
D
r Humod al Hadrami, of the Department of
Petroleum Engineering and Chemistry, in the College
of Engineering, is currently conducting a research project
entitled: Formation damage around boreholes during EOR
process.
Dr Al Hadrami believes that steam injection and other
EOR processes in oil wells is a new technology to be applied in Oman to enhance oil recovery. Formation damage
study and, in particular, borehole stability analysis during
such a process is still a challenge which needs to be theoretically understood and modelled.
This research aims to develop a 3D borehole stability
model using rock mechanics to evaluate and quantify, if
possible, the impact of steam injection process. The study
will consider the implementation of Mogi-Coulomb law
for shear rock failure suggested by a recently published
article.
Effects of local aggregates on
the properties of concrete at
elevated temperatures
He says that taking into consideration
the dates harvesting and land-holding
capacities of the marginalised rural
farmers in Oman, a 12-metre long and
2-metre width tunnel was designed
and constructed to dry about 200 kg
of freshly harvested dates per batch.
The prototype solar tunnel dryer consists of a flat plate air heating solar
collector and drying tunnel, fabricated
as a single unit. The base of the tunnel was made of wooden frame. The
light weight aluminium frames were
used as the upper structure for the entire tunnel to support the transparent
plastic cover. The tunnel was placed
on concrete block substructures 700
mm above the ground surface.
The solar radiation passes through
the afternoon. The highest temperao
ture 690 C was observed at around 1
pm. This indicated that solar tunnel
dryer can be easily used to dry dates.
There was almost no temperature
gradient both in the vertical direction
and horizontal directions of the entire
tunnel.
A no-load test (without dates) was
also conducted without using fan. It
was observed that the highest temperature inside the tunnel became
o
750 C when the fan was not in operation. The difference between the
average temperatures inside the tunnel without and with fan was about
o
100 C. This indicated the operation
of the dryer without fan would cause
overdrying of the product particular
during 11 am to 3 pm.
Dr Basunia adds that the average
initial moisture content of the freshly
harvested dates collected from the
Agricultural Farm of the University
was 32.8 per cent (wet-basis). The
dates were spread on a wire mesh
net in a single layer thickness placed
over the plywood bottom of the drying section of the tunnel.
The drying was started at 7:30
am and continued till 5:30 pm. After
termination of first day drying, the
product was kept undisturbed overnight in the dryer closing openings on
both sides of the tunnel by polyethylene sheet so that air could not pass
through the tunnel.
The moisture content was reduced
to 21.5 per cent from initial 32.8 per
cent (wet-basis) within 10 hours drying on the first day. The next day drying was started at 7:30 am and continued till 5 pm.
D
r Khalifa al Jabri, of the Department of Civil and
Architectural Engineering is currently conducting a
study entitled: Effects of local aggregates on the properties
of concrete at elevated temperatures.
Concrete is a composite material produced from aggregate, cement and water and concrete material in structures
is likely to be exposed to high temperatures during fire.
The relative properties of concrete after such an exposure
are of a great importance in terms of their serviceability of
buildings. In Oman, aggregates used in the production of
concrete are brought from different quarries and such aggregates can have different properties.
Dr Al Jabri believes that the type and properties of
aggregates play an important role in concrete performance when exposed to elevated temperatures. This study,
Dr Al Jabri explains, will investigate the effects of local
aggregates on the properties of concrete at elevated temperatures. It is known that strength degradation of concrete
with different aggregates is not the same under high temperatures and that they may cause an explosive spilling in
concrete causing a considerable reduction in its strength
even at low temperatures.
The relationship between Omani verses and the Arabic model
T
he Scientific Publication Council
has recently published a 93-page
book titled The Relationship in the
past and present between the Omani Poetry Model and the Arabic Poetry Model.
Throughout the five chapters, Dr Ahmed
al Turaisi puts on an academic analysis
that identifies the relationship between
the traditional and current norms that
shape the Omani poem, and compares
them with the norms adopted by poets
around the rest of the Arab world. The
study is claimed to be the first comprehensive academic attempt to touch upon
the subject.
Commenting on his book, Dr Al Turai-
si said: “This is a comparison between
the attributes that have made Omani
poetry distinct from the rest of the Arab
world’s poetry. I have examined the two
models in terms of the usual stages that
a poetic thinking would go through —
and these are emulation, opposition and
intertextuality. The study adopts a western critical concept — the idea of “poetic
models” which begins by overviewing
poets while emulating their traditional
ancestors, then moves on to those who
oppose the way of ancestors to express
themselves and lastly examines the way
poets intertextualise their works.
Various books have touched upon the
emulation stage, several of which are
The Love of the Divine in Omani Literature: an analytical study on Abu Moslem
Al-Rawahi’s poetry by Mohammed al
Salami, The Modern Omani Poetry by
Mohamed al Moharoqi, Omani Poetry in
the Twentieth Century by Mohsin al Kindi, Modern Omani Poetry by Said al Issai
and Imagery and the Formation of Modern Omani Poetry by Issa al Sulaimani.
Similarly, several books talked about
the second kind, some of which are
Omani Poetry: Beginnings and its Imagery Features by Ali Abdul Khaliq,
Studies on the Omani Poetry by Sa’d
Daeebis, Introduction to Studying the
Omani Literature by Ahmed Darwish
published in 1992, and more importantly the study by Said Khalfan al Khalili
(published in Nizwa magazine, issue:
7/1997).
Yet, intertextuality has not thoroughly been discussed, and has mostly been
mixed with the emulation and opposition.
That is because the concept is not entirely well known among Omani students.
So I dedicated many pages talking about
the subject, closely relating it to Issa al
Sulaimani’s study. I finally listed some
on-going researches about the topic that
are taking place here in Oman and also in
Morocco, Tunisia, Egypt and Jordan.
The previously mentioned studies are
highly essential in introducing the poetic
history in Oman and revealing poetry collection to the readers. They also list the
circumstantial attributes that came about
in Omani poetry due to various historical
incidents, which ultimately defined how
distinctive it is from the rest of the Arab
world. Moreover, they specifically discuss the reoccurring language choices,
the music preferences and the imagery,
and their relation to each poet. One of the
conclusions of the book is that though the
language is the same in the Arab world
as a whole, the regional effect prevails
and makes an apparent difference in the
Omani poet — which should not be ignored by any researcher or student.
One of the goals of writing the book is
to ask whether Omani poetry has established over history a distinctive expressive model of its own or not. If that is the
case, how developed is it and how obvious is the difference? If the answer is no,
how did Omani poets express elements
around them in a poetic, musical and expressive language? This approach will
redefine the way the concept of a “modal” have been merely looked at through
the emulation and opposition dichotomy,
to move further into intertextuality in a
modern critical view manner.