AL-Rafidain Engineering Journal (AREJ)

Energy is required for pumping water in the irrigation pipe distribution networks. The need for
this energy and its cost are continuously increasing due to the on-going expansion of the Arab
countries in general and the Gulf countries in particular in using modern irrigation systems in
their agricultural irrigation projects. Most pumped pipe-networks designed on hydraulic basis
only without paying attention to the cost of power, thus huge loss in energy and capital needed
for projects operation occur Sometimes. The design is based on economical basis without taking
hydraulic aspects into consideration which results in low performance efficiency of the system
or damage to the pipe network and consequently high maintenance costs.
The paper presents computerized mathematical model for optimal design of main pipe
distribution networks of sprinkler irrigation system using linear programming. The pressure
head at the inlet of the pipe distribution network is assumed unknown, thus the objective is to
minimize the sum of the initial cost of the pipe network and the cost of energy for pumping.
The constraints included the minimum and maximum pressure head at all points along the
pipes of the network in addition to the flow rates requirements within the network and at the
inlet of each farm .
The study revealed that using the proposed model in the design assuming unknown inlet
pressure head to system has resulted in 9.32% saving in the total cost of the network compared
to the existing design which is based on known inlet pressure head for a selected irrigation
sector inside a large planned irrigation project near Mosul city, northern Iraq.

The strength parameters for sandy soil are not depending mainly on level of stresses but
they are a linear function of width (B) and embedment depth (u) of footing in
Terzaghi\'s solution of bearing capacity. On the other hand, it was found by as called the
non-classical solution conducted by Parkins and Madson (1997) that this relation is
nonlinear and the bearing capacity for sandy soil is mainly relating to width and depth
of foundation, which is known as scale effect. In this work a field model test was carried
out on compacted sandy soil bed for different types of footings with different sizes and
geometry for clarification of the two aforementioned approaches. It was found that two
approaches are consistent and indicating the scale effect well for bearing capacity of
sandy soil. On the other hand, from the field model tests results, it is found that the two
determinations give overestimated bearing capacity values, especially for rectangular
footing with length to width ratio more than 5 (L/B > 5) specially by Parkins and
Madson\'s approach rather than the Terzaghi\'s equation.

Five catchment areas around Mosul city have been selected ( Khoser , West of
Talkief , north of Qayara , Rabeea , and Badosh ) , there were no gauging station for the
surface runoff measurements. Unit hydrograph of ( 3 hr ) duration by using three
models , Nash , Clark , and Saint-venant are used to draw the hydrograph.
The results obtained showed that the Nash and Clark models gave closed results
while the ratio between the peak discharge of Saint-venant to peak discharge of Clark
and Nash are ( 2.5-27.4 ) , ( 1.14-36.23 ) respectively for different catchment.

This work aims to study the effect of erosion on the strength, loss in weight and
gypsum dissolution of gypseous soil stabilized with (4%) lime, take into account the
following variables: initial water content, water temperature, soaking duration or flow
duration and water velocity. The results indicate that, the unconfined compressive strength
decreased for samples soaked in water have low temperature (50 and 250 C), further decrease
in strength with increasing soaking duration. The higher water temperatures (490 and 600 C)
showed increasing in the unconfined compressive strength. High water velocity causes
decreasing in unconfined compressive strength, more loss in weight and more loss in gypsum
content, for all values of flow duration and water temperature.

This research, has dealt with determination of bio-decay coefficient of activated
sludge disposed from wastewater treatment plant of medical assembly in Mosul city.
four bench scale reactors were used of 2.25 liter capacity for each as aerobic digestion
units. Throughout the operation period which lasted for a month temperature was
controlled and it was (15, 20, 25, 30) ċ in the first second third and fourth reactor
respectively, the bio-decay coefficients was found as (kd15=0.02, kd20=0.03, kd25=0.04,
kd30=0.05) d-1 , while the temperature constant (θ) was (1.059). Also the results showed
that the required periods for aerobic digestion process to reduce 50% of biomass
concentration in the reactors at digestion temperature (15, 20, 25, 30)ċ were (17, 7, 5, 4)
days respectively.

This study have used crumb of tyres in asphalt mixture as apart of aggregate.
Three sizes of grade of crumb tyres were used in asphalt mixture (No. 4 (4.75 mm), No.
8 (2.36) mm and No. 50 (300μmm)). Three percentages of asphalt cement (4, 5 and 6) by
weight with three percentages of crumb tyres (2, 4 and 8)% by weight were used with
aggregates for preparing asphalt mixture specimens. Asphalt mixture specimens were
prepared according to Marshall methods ASTM (D-1559). Thirty six specimens were
prepared for evaluating Marshall properties (Marshall stability and flow, air voids
percentage, bulk density, maximum bulk density, and Marshall Stiffness). Indirect
Tensile Strength test (ITS) ASTM (D-1075) at 25oC has been used for evaluating
resistance of asphalt mixture for cracking. For this purpose twenty four specimens were
prepared for evaluating cracking resistance of asphalt mixture contain crumb tyres as
part of aggregates. The study showed that the crumb of tyres has more effects on the
performance of asphalt mixture by increasing the Marshall stability, flow, air voids, and
decreasing bulk density and indirect tensile strength.

The Laser Diode Driver (LDD) is an important part in optical communication system;
it acts as an interface between the data source and the optical source (Laser). The design of
this circuit using CMOS technology which has low conductivity (gm), (less than from bipolar
technology), is a challenge for designers especially at high data rate (>1 GB/s) because LDD
must provide high current swing to obtain large optical output power.
In this research a simulation software using Personal Simulation Program with IC
Emphasis PSPICE (2006) is used to study the performance of the LDD circuit using
(0.18μmCMOS technology) at (1 GB/s), the peak to peak jitter is (110ps). In addition
analyzing an automatic power control circuit, so that when changing the temperature from (0
– 80˚C) the Laser current changing is (5mA), and an improvement of reference voltage
circuit has been added, since a constant voltage (319mV) achieved when the power supply
voltage changes from (2.15-6V).

The asphalt content in hot mix asphalt paving mixture is a key factor in producing
quality pavements. In recent years, the artificial neural networks approach has
attracted wide attention and found a growing number of pavement applications. This
paper explores the feasibility of using the backpropagation artificial neural network
with sigmoid function as activation function by MATLAB 7.8 software to determine the
acceptability of the hot mix asphalt paving mixtures based on the percent of asphalt
content and aggregate gradation using their Marshall properties. Several networks
architectures, using two hidden layers with different numbers of nodes, are tested to
obtained the best results.
The results showed that the network ( 10-20-10-3) had the best performance, and this
network can be used as appropriated method for determining the asphalt content and
aggregate gradation acceptability of hot mix asphalt paving mixture. This work
concludes that the artificial neural network is a good method which can reduce the time
consumed and can be used as a tool in evaluating the hot mix asphalt paving mixtures.

In this paper, a hardware computing unit has been designed and implemented.
This unit computes many elementary functions (such as sine, cosine, tan-1, sinh, cosh,
and square root) that their computing by using software systems requires thousands of
clock cycles as an execution time. The architecture of the function computation has been
designed by using VHDL and placed on XC3S500E FPGA chip in Spartan 3E as a
target technique. In this paper, two algorithms have been used in computing the
mathematical functions, because they can be implemented using FPGA chip. The first is
the Coordinate Rotation Digital Computer algorithm (CORDIC) which was introduced
in 1959. It is a single unified algorithm for calculating many elementary functions
including trigonometric, hyperbolic, logarithmic and exponential functions,
multiplication, division and square root. The second one uses the lookup table.
According to the self-similarity in the trigonometric functions, and using the techniques
of parallel pipelining for the CORDIC algorithm, speedup of (24.7 - 30.3)×100% is
obtained as compared with the other parallel architectures. The throughput became
operation/clock pulse except the first operation whose latency was 32 clock pulse.

Handoff is a feature that deals with the mobility of the user in order to provide seamless
phone call when the user cross the cell borders to another one. WCDMA system is the
third generation system, implements soft handoff (SHO) technique while hard handoff
(HHO) which is used in GSM system. Soft handoff is a technique which allows the user
equipment in the overlap region to link with two or more base stations. The effect of soft
handoff on the downlink direction of WCDMA will be studied because the downlink is
considered as the limiting parameter in CDMA systems. The effect of soft handoff on
the most important parameters of the downlink in WCDMA is investigated using
simulation. Other related parameters of WCDMA system optimization such as load
factor, noise rise, and parameters related to the quality of service like bit error rate
(BER) are investigated. The results reveal that a user in soft handoff consumes less
power from its serving base station. This reduction in the power leads to reducing the
total interference in the cell and hence improving the performance of WCDMA system
by reducing the load factor (loading) and noise rise, and increasing the capacity and
enhancing the quality of service. Furthermore , the results assure why 2-way soft
handoff is commonly used in CDMA system.

In this work, we report the photoelectrical properties of the (CdS/CdTe) structure as
a function of the reverse bias voltage, light intensity and incident power wavelength.
The investigated photodetection performance is located in the visible light spectrum
situated at wavelength range (488-595 nm) and the maximum photocurrent at (505 nm).
The photodetection parameters such as quantum efficiency, responsivity, and
detectivity have been studied as a function of incident power wavelength at different
reverse bias voltages. These studies gave somewhat low values of such parameters which
describe the performance of any photodetector.

Many of modern studies attached special importance to the phenomenon of
incarnating the identity of Architecture. From this, Arab modern studies which was
theoretical and practical, This research concentrates on the subject of identity of
modern Arab Architecture and recognizes it, and comes out with theoretical framework
by previous studies in this context. It appears that elements of theoretical framework
relate to two types. Elements related to incarnation of identity in Architectural heritage,
and elements related to incarnating identity in new products. Each type contained more
subdivisions. The research application concentrate on some of framework items in
practical study for testing it analytically, by choosing the Architect Abed Wahid El-
Wakil to show his work.
The findings show special pattern to El-Wakil by depending on the strategy of searching
for traditional roots in his new designs, which relate to certain values which are
concurrent to theoretical framework. The conclusions answer research queries about
El-Wakil , and confirm thinkers viewpoints of the phenomenon in generally, and to El-
Wakil especially. The findings outline a guide to architects who want to follow the
pattern of El-Wakil for incarnating the identity of modern Arab architecture in their
new design.

weirs are the most commonly used device in channels for flow measurement and flow
regulation due to its simplicity. Conventional rectangular, triangular and trapezoidal
weirs are among the most common oldest types of weirs, progress ogee crest weir and
cylindrical weirs are started to use in hydraulic engineering. The advantages of the
circular weir shape are the stable overflow pattern compared to sharp-crested weirs,
the ease to pass floating debris and the simplicity of design. The concern of this paper is
to study the effect of size and surface roughness of cylindrical weirs on discharge
coefficients (Cd) under different flow conditions.
The work was conducted in experimental flume by using three sizes of cylinders
and three types of surface roughness. The obtained results show that Cd values will
increase with increasing flow rate as well as with decreasing in cylinder diameter; an
increase in surface roughness of weir can makes great reduction in Cd value. The h/R
effect on Cd values increase with increase in cylinder diameter. An empirical relation
was obtained to estimate the coefficient of discharge Cd under different size and surface
roughness of cylindrical weirs.

Growth is presented as one of the important properties which distinguishes flexible
compositions .This property emerges in the middle of twentieth century in some
architectural trends as a reaction towards a problem facing the designers, considering
the production of compositions that can face rapid changes in design requirements over
the time with preserving their architectural identity, however the architecture is a
convertible phenomena . The article discusses the importance of this property and how
it is achieved in architectural products . The framework of this paper consists 0f one
main item (devices 0f achieving growth in flexible compositions) which determine
growth ,firstly, then the application of this item on a sample 0f specialized architects ,
secondly ,finally ,extracting comprehensive description of that property in architecture .
Conclusions have been declared, that growth is achieved by employing both formal and
structural characteristics, considering cellular geometric shape with many similar
fragments or cells which can expand and spread horizontally and vertically like organs,
concentration on the principle of similarity (uniformity) in composing the fragments ,
with articulation as compositional relationships, as well as applying hidden orders
based on modular clustered-grid composition ,traditional structure and zoning space
system.

ارتبط مفهوم السياقية في التوجهات المعمارية المعاصرة ، وقد اكتسب قيمة ايجابية في طروحات مرحلة ما بعد الحداثة وممارساتها ، كأداة لإقامة نوع من الحوار المتبادل بين العمارة والوجود الماثل في المدينة وذلك كرد فعل إزاء مشكلات الحداثة المتعلقة أحداها بفقدان سمة التواصل بين النتاجات المعمارية من خلال تأكيدها على التكوينات الفردية كأجزاء مكتملة بذاتها. يناقش البحث أهمية هذا المفهوم بهدف استكشاف المشكلة الخاصة المتمثلة بعدم وضوح خصوصية ممارسة السياقية في المباني الجامعية. اذ يتميز واقع حال المباني الجامعية وخاصة ذات البناء التراكمي ، بتغير نهج الممارسات التصميمية في مراحلها الزمنية المختلفة مما يؤدي الى ظاهرة انقطاع التواصل التعبيري، وبذلك تبلورت مشكلة البحث وتحدد هدفه ومنهجه متمثلا ببناء إطار نظري يضم ثلاث مفردات رئيسية شملت كل من مفردة الموقف الفكري للمصمم إزاء الموجودات القائمة ومفردة طبيعة مرجعيات الحوار السياقي ومفردة آليات تحقيق الحوار السياقي أولا ، ومن ثم اختيار حرم جامعة الموصل ميدانا للتطبيق ثانيا ، حيث تم تطبيق الإطار النظري على مشاريع معمارية منتخبة لكل من فئة المعماريين الأكاديميين وفئة المعماريين الممارسين بهدف مقارنة خصوصية الممارسة السياقية لتلك الفئات ثالثا . وقد أوضحت النتائج تباين الفئتين وتمايزهم فيما يتعلق باشتقاق السياق كحوار بين النتاجات المعمارية المتغايرة في الحرم الجامعي وفقا لتباين خلفياتهم الفكرية