AL-Rafidain Engineering Journal (AREJ)

The present work deals with the effect of graded coarse aggregates on
some properties of no-fines concrete.
Seven mixes of no-fines concrete having (1-6) (cement - coarse
aggregate by weight) and (50-60%) flow were tried with different
gradation of aggregates (first three were single sized, the remaining
four were graded aggregate with different maximum aggregate size).
The main parameters investigated were the compressive strength,
flexural strength, dry density (unitweight) and thermal conductivity.
The results showed that the use of graded aggregates as compared to
single size resulted in an increase in both compressive and flexural
strength in the order of (56% and 21%) respectively and a lesser
increase of dry density and thermal conductivity in the order of (3%
and 8%) respectively.

The brittle nature of concrete leads to a brittle shear failure, which
the designers try always to avoid by making the flexural strength of the
member less than the shear strength. The addition of steel fibers to
concrete converts the brittle characteristics of concrete to a ductile one,
such fibers are uniformly distributed and randomly oriented throughout
the volume of the concrete. The steel fibers are suitable as shear
reinforcement especially in thin members such as slabs and thin webs,
where the use of shear reinforcement is not possible.
An incremental- iterative method which utilizes the equations of
equilibrium, compatibility of deformations and materials constitutive
relationships is employed to find out the complete response of beams
under increasing shear loads. The method gives detailed information
about the flexural and shear stresses in concrete, steel stresses, cracks
initiation and propagation and failure loads. The results obtained such as
failure load and failure pattern showed good agreement with some
published experimental results

The aim of this research is to study microstructure and some
mechanical properties of ceramic matrix composite material. Powder of
Al2O3 was used as ceramic material after had been pressed by different
pressures (58 Mpa, 117 Mpa and 176 Mpa) in metallic mold. The
sintering process has been preformed at 1200oC for two hours. After that,
the porosity percentage has been measured and the samples were heated
to 700oC and then immersed in the molten pure aluminum and (Al-2.26%
Mg), and heated to about 1000oC for half an hour. Then, the samples
were cooled to 650oC. Microscopic tests and x-ray diffraction analysis
has revealed zones with different hardness and with different structures.
Moreover, the results showed that the adhesion between the ceramic
matrix and the deposited metal depends on the molten metal type and the
percentage of magnesium content of aluminum.

In this paper a higher order finite layer formulation based on the
auxiliary nodal surface (ANS) technique for a free vibration analysis of
rectangular plates is presented. The free vibration analysis has been
performed using the generalized jacobi iteration method, thus finding the
natural frequencies and modes of vibration. In this study, authors consider
the effects of different types of material and dimensions of the plate on its
free vibration analysis.
Many examples have been studied to show the good performance
of the higher order finite layer with one ANS for free vibration analysis
of plate.

Concentration and cumulative depositions of some major air pollutants
(especially Lead Pb and Cadmium Cd ) was measured in six locations
distributed with certain patern in Mosul city .It was possible to survey
more than (10) separate rainfall storms during the period of study.
Locations near the city center exhibited the highest Cd and Pb value due
to heavy traffic .
The level of Cd and Pb is still moderate, but due to probable effect on
Tigris and groundwater as well as direct air quality, it is important to
control sources of these two heavy metals in the future.

This study describes the setting of distance protection for quadrilateral
distance relay for double circuit lines which work at Extra High Voltage
(EHV) by using (MATLAB SIMULINK) to simulate the three phase
faults and states of earth faults for operation at different conditions taking
into consideration the factors which effect on the measured impedance by
relay especially the effect of zero mutual reactance to achieve the best
setting.
The results proved that the setting with earth fault is the same as
with phase fault. Also the change of setting factor causes undetermining
of the fault location accurately. Also the results proved that the effect of
intermediate station causes under reach and the reactance setting for
backup zones tend to match among the different operation states.

High throughput with minimum delay is the ultimate demand being
required from any network. Traffic congestion is the major problem that
deteriorates the performance of a given network. Although switches help
to a large extent in improving the traffic efficiency, but this is not the case
with large scaled networks (WAN for example). VLAN switches play
important roles in further improvements of network performance. The
available types are based on port number and the new versions are based
on MAC address, both types suffer from lack of security. The proposed
VLAN switch provides higher network security because it is based on a
simultaneous port and MAC functions. This benefit justifies the slight
reduction in the throughput-delay performances as compared with the
other types

Data acquisition card has been designed as a card connected to the
industrial standard architecture (ISA) slot in the motherboard of a Pentium
III personal computer in order to control the speed of a DC motor in real
time. A program in C++ language has been written to realize and implement
an algorithm of the controller and to get in and out of the signals to and from
the designed card. The two sampled signals, the speed of the DC motor and
the current in the armature, are processed by using digital proportional plus
integral (PI) control and the output signal is the actuating signal for a
thyristor bridge to control the speed of DC motor. The transient response for
current and speed are drawn in PC monitor in the real time with different
colors using graphics.

In This paper a new adaptive non-communication method offers 100%
Over Head Transmission Line fault clearance instantaneously, is
presented. This Adaptive scheme adjusts distance Measuring Protection
covering full TL in First zone with out waiting the communication intertripping
signals, with high percentage successful three phase Auto_
Reclosing rate. This has been achieved by arrangement of three
instantaneous, fundamental frequency, rms Under voltage Supervisory
Relays controlling Auto_Reclosing command applied to the Circuit
Breaker. The researchers presented a new philosophy to restore Over
Head TL in more reliable and dependable method than the common
existing one. The method utilizes a three phase monitoring Voltage Relay
at each end of the OHTL which control the Reclosing Command. This
new method is applicable approximately to all types of TL protection
Relays (conventional or Modern Numerical Relays).

Spectrum analysis uses Fourier analysis for detecting the spectrum of a
signal. The signals to be analyzed must be stationary that their spectra
must not varying with time. For signals whose spectra varying with time
(non-stationary) such as seismic signal, biomedical signal, speech signal,
Joint Time-Frequency Analysis (JTFA) must be used. The work is to
design PC- based Joint Time- Frequency Analyzer including the methods
that used to calculate and display energy in Time-Frequency domain.
These methods are the Short time Fourier transforms (STFT), Wavelet
Analysis (WT), and Wigner-Ville distribution (WVD). Using the
Graphical User Interface (GUI) for the Matlab software, front panel is
designed as control panel involving all functions and tools necessary for
the analysis.
Hardware requirements for interfacing the signal to the PC are
considered and designed. The sound card used for signals in the audio
range. External signals can be recorded, displayed, measured, stored and
processe in time-domain, frequency-domain, and time-frequency
domain.

Some modernization and immigration have accompanied the
fast transferring from the traditional environment to the modern one.
The complication of Mans life leads to the loss of the social unity inbetween
the old and new combination of societies. Besides, it results
too discover new kind of societies suffer from financial and
economical crisis that its causes have shown the dangerous effect on
the city safety. One of the most important conclusions is the creation
of criminal environment that would be inhabited by outlaws and these
areas would be far away from the justice jurisdiction.
Mixing the usages of the land creates duality in the areas
results out of the handling of these lands. The criminal density and
existence is controversially related to a simple gathering downtown .

A mathematical model to solve a scalar wave equation based on
weakly guiding approximation for multi-layer (or multi-step) optical
fibers is numerically carried out. The suggested numerical method is
suitable to any multi- layer index profile (including W-fiber and
conventional fiber) and sufficiently accurate if fiber materials for
successive layers have small index differences. The general
characteristics of multi-layer fiber such as cutoff wavelength and
dispersion are obtained employing this model.

Mosul is one of the cities that appeared before Islam. Later on it was
reformulated according to the islamic planning principles. It remained a model
of an arabic islamic city, till the beginning of the twentieth century, when it had
witnessed the construction of a number of wide and straight streets penetrating
the urban texture of the traditional city, leading to the destruction of its social
and physical structure. Then, break-through streets started to be more convenient
strategy adopted by the planning authorities to realize their urgent objectives for
raising the quality of life in the traditional city of mosul. After critically
reviewing the previous literature, it was concluded that none of those studies
have dealt, scientifically and objectively, with the problem of defining the
impact of break-through streets upon the spatial organization of Old Mosul.
This defect was adopted as the problem of this study aiming at the definition of
that impact.
Suitable methodology was adopted to realize the study objectives, using
space syntax techniques to analyze and describe the spatial organization of Old
Mosul before and after the adoption of break-through streets strategy.
The conclusions provide a more clear description of the spatial
organization of the old city of Mosul before and after the penetration of breakthrough
street

A procedure is presented for determining the optimum reservoir
size for supplemental irrigation using Linear Programming technique.
The volume of water stored depends on the available runoff during the
time interval considered along the rainy season, and the water demand
which also varies depending on stage of plant growth. The runoff
amount is estimated using the well-known Soil Conservation Services
(SCS) curve number method. The required input data for the model are
the daily rainfall depth for each time interval, soil type, construction
cost per unit volume of reservoir, loss of economical return per unit area
of land left as a catchment, and the maximum allowable catchment area
which depends on total available area of land considered. The
computerized model consists of two parts; in the first part, the program
formulates the input data in the form of Linear Programming problem,
while in the second part the program solves the problem by the Simplex
method. The model is applied using data for Al-Hader area in Nineva
Governorate. The long-term mean annual rainfall of the selected site is
about 150 mm. The results showed that the most economic design is
the one in which the required harvesting area is about three quarters of
the total area under consideration. In this case the yield is sub-maximal,
but most economical, and the irrigation depth is only about 87.5% of the
case that gives the maximum yield. The required reservoir volume for
the most economic design is about 111 m3/ha of the land area
considered.

The study of acoustic insulation for some materials which were used
in most building is investigated in this paper to reduce the noise and
distribance which generated from the different sources. The object is
to the best comfort to the human. A practical device is made by author
and is used in this work. Some of these parts are made in the
workshop of mechanical engineering and the other apparatus
measurements. The concrete block, thermostone and fire block are
used as walls for buildings. The glass was used with thick (4,6) mm
and two layer of glasses with thick 4mm with 10 mm gap, thirospore
and wood are used with thick (20,40)mm and thickness of (3,6,12)mm
respectively. The comparison between above material shows that the
concrete block is the best material being made from the concrete, as a
comparison with other constructions. It was notice when the ration of
mass to density for any material was high, the sound insulation for this
material becomes excellent.