AL-Rafidain Engineering Journal (AREJ)

Nineveh is one of the Iraqi provinces 400 km north Baghdad capital and having
an industrial company for sulfur production. This company produces nearly 20-25% of
the total production as waste materials. This research investigates the ways of recycling
the sulfur waste (SW) in solving the higher cost problem coming from import of
waterproofing materials and presents information on the program and laboratory test
data. Materials used in test program included 40/50 asphalt cement, Alkyl benzene
sulfonate (ABS) and sulfur waste (SW). Five SW contents 0, 1, 3, 5 and 7%, and 1% of
ABS in terms of asphalt cement by weight were used. Tests including physical
properties, compatibility, storage stability, aging properties, temperature susceptibility
and water permeability were carried out in accordance with the ASTM procedure. The
test results revealed that SW is a reliable material for paving asphalt cement and being
readily available can be widely used in water proofing construction materials, and this
offers profound engineering and economic advantages

T he current research work caters for the possibility of arriving at a method for
designing concrete mixes (job mix) using locally available materials by means of three
prescribed properties of the mix as design pre-requisites, that is water content, water :
cement ratio and aggregate : cement ratio of wide ranges to cover a good variety of
practical mixes. The above mentioned three prescribed properties can be represented in
a graphical solution manner using a trilinear diagram depending on the fact that the
absolute volume of the concrete mixture consisting of three materials, cement, water
and aggregate is the sum of absolute volumes of the three materials. As a result and
from this representation a quadrilateral area can be formed which should include a
wide range of mixes having all the prescribed properties mentioned above. The current
work will consider the following main influencing parameters on the job mix:
1. Water : cement ratios between 0.35-0.84.
2. Maximum aggregate sizes of 20 and 12.7 mm.
3. Fine aggregate ranges of fine, medium and coarse (B.S 882-1992 [11])
4. Aggregate : cement ratios between 3.8-7.6.
Key words: Concrete mix design, Compressive strength, W/C, A/C, Water demand

The causes of reflective cracking can be either environmental and/or load associated.
The simultaneous movements of an overlay caused by wheel loads (vertical movements),
temperature changes, temperature gradients (horizontal movements) induce a complex
stress state of cyclic bending tension, and shear within the overlay.
Different types of tools are used to simulate the mechanism of reflective cracking in
the laboratory , in this research only the tool which simulates the effect of temperature
variation (horizontal movement) is studied. Overlay Testing Equipment is constructed
and tested in Iraq . All the tested samples are beams of dimensions 7.6cm width, 38.1cm
length with different thickness. Three parameters are taken in this study, filler type,
thickness of asphalt concrete beams and additives and their effects on the properties of
asphalt concrete mix. From the results, the samples prepared by limestone as a filler give higher number of cycles than that prepared by cement, the samples of high thickness give higher number of cycles and the control sample gives best results than modified samples.

The research focuses on water desalination by distillation process under
condition of vacuum pressure. The distillation unit was elevated over the ground
surface then water was sucked from it. The water was boiled at temperatures below
(100)oC as a result of reaching the absolute pressure to the vapor pressure values of
water at these temperatures. The distillation unit was elevated at (6.27-7.15-8.25)m over
ground surface, so that the absolute pressures exerted were (37.54-27.76-18.21)kPa
respectively and the boiling points were (78-72-62) oC respectively. At each elevation of
the distillation unit, different values of temperature were applied on the saline water
samples (with same concentration and volume). The results indicated increasing in
evaporation rate with increased elevation from ground level and with increasing of the
applied temperature. This is linked with increasing in evaporation energy as a result of
(boiling heat flux) increasing with the depression in absolute pressure and with
increasing in temperature. The average increasing in evaporation rate was (6.78)cm3/hr
for each (kPa) depressing in absolute pressure and (7.41) cm3/hr for each (oC) rising in
temperature. The condensation tube was designed for each boiling and evaporation
process depending on mounting the condenser at atmosphere. The design was affected
by the variation in temperature and pressure applied.

Misalignment problem is considered as one of the most important and common
repeated problems in rotary kiln in meanly all of cement factories. This will lead to
generation of vibration and extra loads on bearing of the carrying rollers. Also a nonuniformity
can occur in distribution of applied load on all the surface of the bearing
which being concentrated on one or two sides of the bearing surface, and finally leads to
falling the fire lining.
The present research work is concentrated on the analysis of stresses generated
on bearing of the carrying rollers of the rotary kiln in new Hammam Al-Alil factory. In
addition the effect of misalignment is shown on stresses distribution and it's
concentration. This is important for the bearing design and those who work in bearing
maintenance in this factory.
The "(ANSYS 9.0)", which uses a finite element technique, had been utilized in
this program. This is a very efficient and accurate tool in stress analysis for many cases.
The stresses had been calculated for the assumed cases.
The results showed clearly that the stress distribution and concentration on the
bearing is altered with misalignment for each case.

Gypsiferous soils have specific feature under its suction studying. These soils
contain salt solution that affects on the suction components at high water content levels.
This paper investigates soil suction of three types of gypsiferous soils namely: Al-
Muhallabeia, Al-Jarin, and Al-Slmanii using filter paper technique. The investigated
soils were located in Nineveh province (400 Km north Baghdad capital) and found to
have a gypsum content of about 35, 23, and 6%, respectively.
This study includes some factors (water content, gypsum content, and clay
content) that affect the soil suction for gypsiforous soils. The effect of gypsum content
on slope of the relationship between soil suction with pF unit and water content was
examined.
The results revealed that there is a linear relationship between soil suction and
its water content for three studied soils. Both total and matric suction values increase as
soil water content decrease. On the other hand, the difference between total and matric suction values increase with soil samples water content. The soil clay content has more effect on gypsiferous soil suction than its gypsum content.

Computer model is made in (MATLAB) language to study the effect of deficit
irrigation with saline water on the salts accumulation in soil and the effect extent of the
lack of water and the salts accumulation on yield. The Model has been applied on
summer crop, Maize, and it relies on the principle of balancing water and salt. The
Model are uses the basic variables entered in the irrigation (climate data, crop type, soil
type, and the rate of moisture depletion , irrigation level, the initial soil salinity and
salinity of irrigation water). The results obtained from the program are (daily potential
and adjusted Evapotranspiration, daily balance of water and salt, the quantities of
irrigation water and Perfusion appointment, The rate of change of concentration of
salts before and after Perfusion, electric conductivity of saturation extract at Slaking,
calculating the relative defect of seasonal yield). study show when using a little amount
of irrigation water we have a little salt accumulation in the soil, but the salt
accumulation at the end of the season depends on the gross depth of irrigation water
added . Low levels of irrigation led to lower proportional yield in the event that the
impact of water shortage was bigger than the impact of irrigation water salinity on
productivity, and vice versa. Formulation of mathematical equations to find the relative
yield and seasonal actual Evapotranspiration because of irrigation water salinity and
water shortage, under the condition of study area and determinants.

In recent years, there is a growing interest in the use of crushed sand obtained
from limestone quarries in some countries where river sand is not widely available.
Besides, the demand for aggregates to produce concrete is still high while natural
resources decrease. The fines content in limestone is usually high (particles with a size of
0.15-0.7 mm) which can affect concrete properties in an either positive or negative way.
Studies on aggregate containing fine materials are vitally important. However, little
work has been done so far on the effect of fines in crushed sand on the properties of
concrete.
This paper examines the influence of limestone filler in sand on concrete
properties, which include workability of fresh concrete (slump test method),
compressive and tensile strength, unit weight, and ultrasonic pulse velocity. Six concrete
mixtures containing different ratios of limestone filler (0, 10, 20, 30, 40, 50) % sand
replacement were used while maintaining a constant water/cement ratio. The results
proved that limestone filler replacing sand up to 20% without adversely affecting
concrete strength.

Dual twins in architecture have been widely spread since the middle 20th century in
various parts of the world; however, the unclear and comprehensive view about the nature and
reasons of the emergence of such phenomena is still not established. The current study attempts
to determine the nature and reasons of the emergence of such phenomena clearly and
comprehensively. In order to examine the theoretical background of this phenomena, concept of
twins in language, philosophy, biological and medical sciences is reviewed in addition to
examining principles of dual architectural and artistic composition and the priors of dual twins
in history of architecture. Thus, the two hypothesis of the study are formed where the first
states that dual twins are either identical or fraternal, related or not related materially with
each other. The second indicates that unity of design is the reason behind the emergence of dual
twins leading to aesthetics, integrity within the urban context.
The study has made a deductive survey of 27 of dual twin buildings around the world.
The study concluded that both the hypothesis are largely met but not absolutely. There are
identical and fraternal twins but not materially related with each other and characterize by a
complete structural and functional independence with their visual interrelation forming both of
them as one dual composition. Concepts of architectural composition aiming at breaking
monotony and presenting the new were the most influential in the emergence of dual twins in
architecture in addition to other functional, rational, urban and environmental causes.

The magnetic electron objective lens is of a great importance which limit the
resolving power of the electron microscope.
The present work investigates the objective focal properties of a single
polepiece magnetic electron lens of truncated cone polepiece shape of the selected
geometrical dimensions for practical applications. The lens has been fabricated
consist of cast shield made of mild steel combined with exciting isolated cooper
coil of 500 turns.
The theoretical and experimental results presented the magnetic flux density
distribution and the objective focal properties of the lens, in mode of operation
when the direction of incident electrons beam facing the lens back plate of the
lens.
Moreover, the theoretical and experimental results are in a good agreements.

In this paper, natural convection heat transfer of supercritical water in rectangular enclosure has been investigated in various values of reduced temperature (0.955 1.205) and pressure (1.2 2.0). The right and left sides of enclosure considered to be isotherm with a temperature difference of , while the lower and upper sides of the enclosure was thermally insulated. The width of enclosure is 0.004m. Calculations were performed for Rayleigh number ( ), Prandtl number ( ). The values of Ra and Pr are governed by the fluid temperature and pressure which are controlled by reduced temperature( ) and reduced pressure ( ). Streamlines, isotherms and mean Nusselt numbers are presented. It is found that the temperature distribution and flow field are affected by the reduced temperature and pressure. The results also show that the maximum Nusselt number could be obtained at the same specification of geometry and temperature difference increases as the pressure reach the critical pressure.

This paper presents the theoretical analysis and experimental study of the
performance of a shallow fluidized bed as a storage system for thermal energy.
River sand is used as a bed with different height values and compressed heated air
as an external fluidizing.
A bundle of finned tubes is used as a heat exchanger immersed in the bed for the
extraction of stored energy from the bed.
Empirical correlations are offered by experimental work, which show the relations
between the instantaneous local temperature within the bed and time as a function of
both bed height and inlet air velocity.

T his paper develops a system level architecture for implementing a cost-efficient,
FPGA-based reconfigurable two dimensional (2D) FFT system. The adopted approach
considers both the hardware cost (in terms of FPGA resource requirements), and
performance (in terms of throughput). These two extremes are optimized based on
using run time reconfiguration, double buffering technique, shared Dual Ported RAM
(DPRAM) modules and the “hardware virtualization” to reuse the available processing
components. The system employs two one Dimensional (1D) FFT processor each with
sixteen reconfigurable parallel FFT cores. Each core represents a 16 complex point
parallel FFT engine. Thus the architecture supports transform length of 256X256
complex points, as a demonstrator to the design idea, using fixed-point arithmetic and
has been developed using radix-4 butterfly architecture. The simulation results that
have been performed using VHDL modeling language and ModelSim software
shows that the full design can be implemented using single FPGA platform
requiring about 50,000 Slices.

The divergence of computers, internet, and wide variety of interactive video devices,
in most of the multimedia applications, all using different color representations, is
forcing the digital designer today to convert between them. The objective is to have a
converter, which will be useful for number of applications with a basic function of
converting from one color space to another and the inverse on same architecture. This
paper presents an efficient parallel multiplierless implementation for two color space
converters (RGB to YCbCr and YCbCr to RGB). The proposed architecture is based on
distributed arithmetic (DA) principles which has been implemented on the Xilinx
Spartan-3E XC3S500 FPGA using fewer resources. The implementation approach
exhibits better performances when compared with existing implementations,
Modifications have been carried out in DA to reduce the hardware complexity with
better performance in area, latency and throughput.

In this paper the hydraulic characteristics of V-notch broad crested side weir have
been experimentally studied. Sixteen V-notch broad crest weirs were constructed with
six apex angles (θ=30º, 45º, 60º, 90º, 120º,and 150º)and the apex height change three
times (p=5,10,15cm) for the first forth angles and change two times for the last two
angles (p=10,15cm), each model can be tested by changing flow in the main channel
several times and from the analysis of experimental results it was found that the
coefficient of discharge(Cd) for the V-notch broad crested weir is depend on the
hydraulic and geometric characteristics of channel and weir, and from the hydraulic
characteristics of the main channel it was found that the coefficient of discharge (Cd)
directly proportional to the main channel Froude number before side channel , and a
maximum value of (Cd) can be reached for a larger acute V-notch angle , but a
maximum value of (Cd) can be reached for the smaller obtuse V-notch angle. Also from
the hydraulic and geometric effect for both channel and weir it is found that (Cd)
inversely proportional with (y1/p) and directly proportional with (y1/h &p/h) and a
maximum (Cd ) can be reached maximum for both acute and obtuse V-notch angle.
Suitable equations for discharge coefficient are obtained for different apex angle, then
the predicated discharge coefficient from the equations were plotted against the
calculated value with coefficient of determination (R2=0.9) and it was found to be good.