Al-Rafidain Engineering Journal (AREJ)

ABSTRACT
This study was carried out to determine the influence of the randomly oriented discrete
steel fibres on the bearing capacity of plain concrete through testing concentrically loaded
150mm square prisms. The concrete strength, ratio of total area to loaded area, height of
prisms, dimensions and fibre percentage were varied throughout the investigation.
It was found that the bearing capacity increases with the concrete strength and the ratio of
the total to loaded area both for the plain and for the fibrous concrete.
It was also found that the bearing capacity of steel fibrous concrete was significantly higher
than that of unreinforced concrete, and showed ductile mode of failure and retained their
integrity also at failure. It was also found that the bearing capacity of fibrous concrete
increases with the aspect ratio of the used fibres.
Prediction of the bearing capacity both for the plain and fibrous concrete using the limit
theorems of perfect plasticity showed fair agreement with the experimental results.
KEYWORDS: Bearing capacity, concrete, limit theorem, plasticity, steel

Abstract
The research problem has been determined through the necessity of the
architectural elements and determining their relations to one anther with the aim of
studying the shifts that have been taken place in Mosul architecture. The research
methodology encompasses the application of this frame to buildings that date back to
the various stages of architectural change. Consequently, to find out change that have
occurred in Mosul architecture elements and the diachronic relations which testify to
either continuity or change in it. The research also embraces the method of collecting
data on building samples. These include (20) building samples chosen according to
objective criteria. Then, a case study on these samples has been applied using a special
formula. In Consequence, results relating to the research hypothesis have testified,
together with the finding, significant variance between the architectural phases through
the changes that have taken place in the architectural elements.
Keyword: Mosul architecture, architectural stages and change.

Abstract
This paper presents a numerical model which is capable of predicting the behavior of
fibrous prestressed concrete beams and frames subjected to cyclic loads. The stiffness method with
the effective secant stiffness is used here in analyzing plane structures, while the analysis of member
cross sections that are subjected to cyclic loads is carried out in combination with the layered section
approach. Material nonlinearity has been taken in to consideration through the analysis of these
sections. This method deals only with axial forces and bending moments neglecting the effect of
shear forces. The study presents a program written with MATLAB language that analyzes structures
by the STIFFNESS method and divides the cross sections into small layers in order to utilize the
nonlinearity of the stress distribution along the section depth. The results at each section are
moments, curvatures, displacements, forces, stresses and strains under each load cycle. A cyclic
model for fibrous concrete subjected to uniaxial compression or tension has been proposed. Also the
cyclic model of Menegotto and Pinto for conventional and prestressing steel has been adopted. Full
bond between steel and concrete is assumed.
The study shows that the prestresssing force in concrete members has reduced the
ductility or capacity of energy dissipation, while a noticeable increase in the member failure load is
recorded. Moreover, the existence of steel fibers in concrete enhances its stiffness, delays the cracks
The scheme of and then narrows their openings in tension zone and decreases their negative effect.
the layered section presents more reliable stress distribution on the cross section of the concrete
members.
Keywords: Concrete, Cyclic Load, Frames, Prestress , Steel fiber.

the effect of waste from textiles dyeing
operation on the engineering properties of Expansive clayey soil .The tested
soil was obtained from of Al- Yarmook district-Mosul-City, which be
described as light brown stiff clay ,an inorganic type with high plasticity
(CH) , It contains (38%) clay size particles (

Abstract
Oxygen transfer capacity has greatest influence on activated sludge performance. In
this study, experimental procedure is carried out to determine the effect of airflow rate and the
level of diffusers submergence, on the oxygen transfer rate of diffused air systems. In addition,
a number of readings were also collected from published papers. The data were selected to
cover various scales of plants and operating conditions. After sorting out, all data were treated
and then combined to the experimental readings in order to expand the applicability of the
results. Individual mathematical models to describe the effect of each parameter were also
derived. The results of the study showed that, increasing the airflow rate at fixed water depth
and diffusers submergence enlarge the oxygenation capacity of the system. The equation, which
controls this relationship, is linear. At diffusers submergence of 4.6 m, the slope of the equation
was 11.8. With reduce the depth of diffusers to about 0.4 m; the slope of equation was decrease
to 2.3. At constant airflow rate, the depth of diffusers has a significant effect on both of the
oxygenation capacity and oxygen transfer efficiency of the system. Exponentional form of
equation is shown to be efficient in expressing the relationship between the submergence and
the oxygenation capacity. At 0.4 m, diffusers submergence, the oxygen transfer efficiency was
1.8 whereas; this value is rising to about 11.5 at 4.6m submergence.
Keywords :Oxygen transfer capacity, diffused aeration, airflow rate, diffusers submergence, KLa

Abstract
Longitudinal and radial stresses in a M.V. and H.V. cables through terminals
are computed using Schwarz Christoffel transformation for field sketching.
The terminals and associated cable are rated at 11KV, 33KV and 132KV a.c
insulated by cross–linked polyethylene (XLPE). The electrical field sketching at the
cable terminations is carried out theoretically and the results are confirmed by
experiments.
It seems that the maximum stresses occurs in the cable insulation and the
maximum longitudinal stresses along the screened outer surface of the cross-linked
polyethylene (XLPE) insulation occurs between the cable and the termination center.
The results show that the maximum longitudinal stress is many times the
oncorrespding maximum radial values.
Key Words: Stress distribution for XLPE cable, Termination of XLPE cables

Abstract :
In this research thin film layers have been prepared at alternate layers of
resistive and dielectric deposited on appropriate substrates to form four – terminal RY-
NR network. If the gate of the MOS structures deposited as a strip of resistor film
like NiCr, the MOS structure can be analyzed as R-Y-NR network. A method of
analysis has been proposed to measure the shunt capacitance and the shunt
conductance of certain MOS samples. Matlab program has been used to compute shunt
capacitance and shunt conductance at different frequencies. The results computed by
this method have been compared with the results obtained by LCR meter method and
showed perfect coincident with each other.
Keywords: Thin Film R-Y-NR Network; MOS R-Y-NR Network

Abstract: frames under C.L
The applications of Discrete Wavelet Transform necessitate fast computation. Full-custom
VLSI devices (ASIC) have been used for fast though expensive implementations of DWT.
Field-Programmable Gate Array (FPGA) architectures offer economical but area-constrained
implementation of DWT. The present paper proposes an important issues on the design and
simulation of ASIC and FPGA architectures for 1-D DWT as well as inverse DWT on a
single chip using VHDL simulation tools. The design of the programmable chip that can be
used as 1-D DWT or IDWT is introduced based on two quadrature mirror filters (QMF), one
used with DWT (decomposition) and other used with IDWT. The design is modular; the chip
can easily be worked as DWT or IDWT with ability of selecting one of the four
corresponding types of QMF wavelet filters (Daubechies 1, 2, 3 and 4).
The first chip is implemented and simulated using FPGA for two word lengths 8-bit and
12-bit respectively. The results show a clock speed of 66.2 MHz for 8-bit, and 55 MHz for
12-bit. While the design of ASIC chip validate a clock speeds 85.5 MHz and 59.2 MHz for
8-bit and 12-bit respectively. Simulation results have established that the higher word length
increase accuracy but at the expense of higher designed size and longest combinational logic
between two storage elements. This means increasing the length of critical path as result of
complexity which decrease the maximum speed clock.
Keywords: VHDL, Wavelet, FPGA, Architecture.

Abstract:
Steady free convection through a porous medium around a rectangular isothermal
body has been numerically investigated. The isothermal body is kept at constant low
temperature and the porous medium has an impermeable rectangular boundaries. The cavity
wall of porous material has a constant high temperature.
The full governing equations (momentum an energy equation) have been solved for
range of values of the governing parameters by using the finite difference method and
covered a wide range of modified Rayleigh number (Ra) (0-500) with different sizes of
isothermal body. Results are presented in terms of the streamlines and isotherms to show the
behavior of the flow and temperature fields. This study shows that the Nusselt number (Nu)
is a strong function of the modified Rayleigh number, the isothermal body size and boundary
conditions. For certain range of Ra, the rate of heat transfer decreases when the flow divided
into primary and secondary cells

Summary
This paper covers the theoretical and practical evaluation of straining which arise due
to stressing, and plastic deformation during the deep drawing process of the production of
the shells for LPG cylinders, as well as the process description and application. Therefore
the study includes experimental work in the field of metal drawing in stages for different
depths to tabulate the radial metal movement and changes in shell thickness and diameter.
As the annealing treatment has an important role in the production sequence, so samples of
metal used in producing the domestic LPG cylinder were heat treated in different situations
to study the influence of an annealing operation on the metal (its microstructure,
metallurgical, and mechanical properties