Tikrit Journal of Engineering Sciences

The research aimed to classify 66 wells within and around Mosul city according to their
water quality using cluster analysis. Water samples were collected and analyzed for pH, total
dissolved solids, conductivity, calcium, magnesium, chloride, sulphate and bicarbonate using
standard methods. The data were analyzed statistically using factor and cluster analysis. The
results of factor analysis show four groups. Conductivity, total dissolved solids, sulphate and
calcium represents the first group with the highest percent of variation (30.55%) between wells.
Cluster analysis divided the wells into four homogenous clusters. The first cluster represents
15(22.7%) of the wells, most of the wells of this cluster are distributed along Tigris river with
lowest pH, highest sulphate and bicarbonate concentration. The second cluster includes the
largest number of wells 33(50%) with the lowest salinity since it had the lowest conductivity,
total dissolved solids, calcium, magnesium and chloride. The third cluster with 4(6.1%) wells,
had the highest salinity since it had the highest conductivity, total dissolved solids, calcium,
magnesium and chloride. The fourth cluster includes 14(21.2%) of less acidity wells with highest
pH and highest bicarbonate concentration. The research concluded that cluster analysis could
be used as an efficient statistical grouping tool according to water quality parameters.
Additionally, factor analysis can be used to analyze a large number of data and study the
variation in water quality.

A computer simulation is important for the analysis geometry of freeways and urban streets systems.
Transportation specialists can study the formation and removal of congestion on roadways. The
intersection is one major cause that has a significant effect on travel time, delay, level of service, queues,
stop, performance index, degree of saturation and capacity. The target of this paper research is to
analysis the geometry and intersection classification of traffic flow to provide useful information for
engineers to design the roads with the shortest travel time and enhance the capacity of road networks
and relieve the congestion in cities.
The data required for the study were mainly collected from through video filming technique also the
calculation and evaluation are constructed with the aaSIDRA software in the 2011.

This paper presents the implementation of the Fast Walsh Hadamard Transform (FWHT) in sequence
ordered method, in order to minimize the interference due to two users trying to transmit at the same time,
and an attempt has made to simulate them. The simulations designed satisfy most of the requirements of
the parameters mentioned in the 3GPP specifications. The main objectives of this paper are to construct a
model using MATLAB 7.4.0(R2007a) to illustrate the simulation.
In image processing and pattern recognition the motivation for using transforms other than Fourier is
either to reduce computation time for a given resolution, or to increase resolution without increasing the
length of the computation time and to minimize the hardware resources. Fast Walsh-Hadamard Transform
has been used effectively to satisfy these requirements.

In contrast to conventional voltage sensor technology (e.g., inductive voltage
transformers or capacitive voltage transformers), optical sensors have inherent and
advantageous features, such as wider bandwidth, larger dynamic range and lighter weight.
The aim of this work is to implement an AC voltage sensor based on Pockels electro-optic
effect in LiNbO3 crystal. The research has been conducted in two ways .The first way is the
installation tested uses external electrodes and a He-Ne laser as a light source, whereas the
second way is by using the direct voltage application to the metalized sides of the LiNbO3
crystal built into an optic cell. Results of both tests shows that by using the direct voltage
application to the metalized sides of the LiNbO3 crystal built into an optic cell led to better
repeatability of voltage measurements and corresponds to more realistic conditions.

In this paper a complete model of aircraft electrical system is simulated and analyzed using 24-
pulse techniques in power conversion. The classical aircraft electrical system is described in this
paper. The performance characteristics of 24-pulse converters are studied with different
conditions of operation and the simulated model is tested with different jet engine speed which
yields to different frequencies of operation from 400Hz to 1200 Hz. The simulated system is
described and analyzed in two sections; Generating-Rectifying and Inverting unit. In order to
match the practical condition, different types of load are considered here such as; constant
power load, constant voltage load, constant current load, passive and dynamic load. The
voltage and current for the generator side and inverter side are recorded and the total harmonic
distortion (THD) is calculated for different conditions of operation. The obtained results are
compared with conventional 6-pulse converters which are used in classical aircraft electrical
power system. The proposed system is simulated and analyzed using the PSIM 9 software
package with analysis completed in MATLAB 2010.

The need to produce high performance concrete led the researches to try to exploit the
potentialities of natural or artificial materials so as to improve the performance of concrete. White
sandstone powder has been used as an alternative of proportion on cement after being processed,
since its main oxides are similar to those of cement.
The aim of this research is to study the effect of added (10,15,20,25)% white sandstone powder as
replacement of cement, used in concrete mix which it has a mixing proportion of
(1:1.6:1.2;w/c=0.28), and it is shown their effect on some of mechanical properties (compressive
strength, splitting tensile strength, and flexural strength).
The test results shows clear improvement in some mechanical properties of concrete by using 20%
sandstone powder. The increment ratio in compressive strength, splitting tensile strength, and
flexural strength were (32, 42.5, 31.6)% respectively for each compared with reference mixture for
the same duration.

This research work includes an experimental investigation to study the mechanical properties of
reactive powder concrete (RPC) exposed to acidic solutions. A comparative study was conducted
on concrete mixes, control mix without exposure and mixes exposed to acidic solutions. RPC was
exposed to two acids (Sulfuric acid and Nitric acid) with concentration of (1.0)% for each acid. The
acidic solutions were used to study acidic rain effect and durability of RPC. Compressive strength
test was used to study the effect of acid rain on RPC after exposure to the acid in a duration (48)
hours. This exposure was done: after demolding and after (3 and 7) days curing. The maximum loss
in compressive strength for Sulfuric acid and Nitric acid was (11.7 and 19.7)% respectively for after
demolding exposure as compared with the control mix.
For durability of RPC the specimens exposed to acidic solutions tested in duration (40, 50, and 60)
days, to determine the compressive strength, splitting tensile strength, flexural tensile strength, and
weight loss. Test results showed that RPC resistance to Sulfuric acid more than Nitric acid. The
maximum loss in compressive strength, and loss in weight were (6.20 and 2.69)% in Sulfuric acid
and (22.60 and 1.32)% in Nitric acid environment respectively at (60) days as compared with the
control mix. The loss in splitting tensile strength and flexural tensile strength were (17.1 and 13.3)%
for Sulfuric acid and (25.7 and 25.0)% for Nitric acid exposure respectively at (40) days as
compared with the control mix.

Anisotropy on compression, strength and permeability of a clayey soil selected from Mosul
city was studied in this paper. Laboratory standard tests were conducted on sets of duplicate
disturbed and undisturbed specimens prepared in the vertical, 45º inclined and horizontal directions
from block samples retrieved from the site. The one dimensional consolidation of the clayey soil was
shown to be cross-anisotropic for the vertical and horizontal directions, the 45º inclined showed an
intermediate results. Drainage occurred more rapidly in the horizontal direction comparing with 45º
inclined and vertical directions, with horizontal to vertical permeability ratio (rkh) not less than (2.0) for
disturbed and undisturbed specimens from both consolidation and permeability tests. Compression at
higher effective stresses caused significant reductions in the coefficient of consolidation (cv) and
permeability (k) although the rk values remained independent of the stress level. Furthermore the
clayey soil specimens were noticeably anicotropic in strength, where the relationship between
stresses and strains for vertical, 45º inclined and horizontal directions exhibited consistently dissimilar
peak values as well as deformations at various strain levels.

Overall gas-liquid mass transfer coefficients of oxygen gas (KLa) at different axial
locations of the riser and downcomer of a split-column Airlift Photobioreactor were
investigated using FOXY Fiber Optic oxygen sensor supported by NeoFox viewer software.
The effect of bubble dynamics on mass transfer was considered. A 4-point optical probe was
used to measure local interfacial area (a) and other bubble dynamics parameters for both the
riser and the downcomer of a split-column airlift photobioreactor. Having both overall mass
transfer (KLa) and interfacial area (a) measured at different locations, local oxygen mass
transfer coefficient (KL) can be determined for each location along the riser and the
downcomer of the airlift bioreactor. Effects of different operating conditions (0.3 – 2.8 cm/s
superficial gas velocity) on both mass transfer and bubble dynamics of the riser and the
downcomer have been investigated for air-water system. It was found that both local mass
transfer and gas-liquid interfacial area are considerably varying from the bottom to the top of
the riser and the downcomer of the bioreactor. It was found that local mass transfer coefficient
varies by 100% from the bottom to the top of the riser at low superficial gas velocity (1 cm/s)
and by 30% at relatively high velocities (2-2.8 cm/s). The Trend of the variation of the KLa in
the downcomer section of the column is very different from that of the riser, as it was noticed
that insignificant mass transfer takes place at the lower part of the downcomer. The results of
mass transfer and bubble dynamics in the riser and the downcomer of the studied conditions
will be presented and discussed.

Petrochemical industry, specially oil refineries produces large quantities of wastewater that is
strongly polluted with hydrocarbon compounds. Although Baiji oil refinery has wastewater
treatment plant, it discharges water to Tigris river that is strongly polluted with hydrocarbon
compounds that exceed the Iraqi permissible limits. Thus the aim of the present work is to
remove phenol, parachlorophenol, and benzene from the wastewater of Baiji oil refinery using
granular activated carbon(GAC)column. A laboratory scale apparatus is designed and
constructed in order to perform this study taking into account the ability to control the most
important parameters affecting adsorption process. Actual wastewater samples taken from the
final discharge point of wastewater treatment unit of Baiji oil refinery are used to conduct all
experiments.
The results indicated that these pollutants could be removed completely. Moreover, it indicates
that breakthrough and exhaustion time are directly proportional with GAC thickness and inversely
proportional with pollutants concentration and liquid hourly space velocity (LHSV). The results
show that maximum breakthrough time is 39.26, 21.35, and 16.58 hours at LHSV of 0.5 hr-1 and
35cm of GAC thickness for phenol, parachlorophenol, and benzene respectively. The
corresponding minimum breakthrough time is 9.24, 5.23, and 6.08 hours at LHSV of 129 hr-1.
However, the corresponding maximum exhaustion time is 49.6, 48.7, and 43.84 hours, while the
minimum exhaustion time are 27.5, 16.54, and 10.89 hours. The results show that breakthrough
time for phenol is 27.23 hours when the phenol inlet concentration is 5.212 mg/l, it decreased to
13.83 hours at inlet phenol concentration of 19.31 mg/l. The corresponding exhaustion time is
68.83 and 37.22 hours. Other two pollutants have similar trend. Based on the experimental data,
dynamic adsorption capacities are calculated and found to be increased with the increase of
pollutants concentration and LHSV. It is also found that calculated adsorption zone thickness is
proportional with LHSV. The calculated maximum dynamic carbon adsorption capacity are 115.4,
67.62, and 12.628 mg/g for phenol, parachlorophenol, and benzene respectively at LHSV of 129
hr-1. The corresponding minimum capacity at LHSV of 0.5 hr-1 are found to be 1, 0.99, and 0.257
mg/g. Calculated values of minimum and maximum adsorption zone thickness for the three
pollutants at LHSV of 0.5 and 129 hr-1 are (0.0729, 0.1965, and 0.2176) and (0.2324,
0.2118,and 0.1545)cm respectively.
Application of the most famous the adsorption models shows that only Freundlich model gives
excellent agreement with experimental data. Finally, new three models are developed. The first
and second relate breakthrough and exhaustion time with LHSV, wastewater pollutantsconcentration, and GAC thickness while the third relates adsorption velocity with LHSV and inlet
pollutant concentration.