Print ISSN: 1681-6900

Online ISSN: 2412-0758

Volume 25, Issue 0

Volume 25, Issue 0, February 2007, Page 34-327


Production Composite Materials by Fused Deposition Method

Engineering and Technology Journal, 2007, Volume 25, Issue 0, Pages 44-60

The aim of this research is to produce composite materials with ceramic base
covered by a layer of (Al) and its alloys by means of fused deposition technique.
This technique represents new method and combines the powder technology with
the casting technique. Al2O3 poweder was used after having been pressed by
different pressure(58,117 and 176 MPa) in metal molds. The sintering process has
been preformed at 1100 o C for two hours. After that, the porosity percentage has
been measured and the samples were immersed in the molten metals heated to 700o
C . Ultirnatly, these samples were heated to about 1000 o C by a furnace for half an
hour. Then,the samples were cooled to 650 oC and examined by an optical
microscope and the scanning electron microscope. Moreover, the x-ray diffraction
for these sample has been employed to define the structure of the resulting
composite as well as to define the resulting bond between the deposited metal layer
and the ceramic matrix in addition to characterize the existing phases within the
composite material.

Numerical and Experimental Study of Ice Storage in Air Conditioning Systems

Engineering and Technology Journal, 2007, Volume 25, Issue 0, Pages 61-75

An experimental and numerical study done to design and analysis ice storage in
air conditioning system on building with three types of cooling load. The design
system was active to produced thermal comfort to the building. The non-operating
hours of the building was defining and used to collect ice on the out surface of
pipes in the ice storage system. To predict the radius of the formatted ice an
enthalpy method used with B.F.C. system used and the results compared with the
experimental results from measuring the radius of the ice formatted in a rig build
and run with the same boundary conditions. The theoretical results shown good
coincident and the small deviation in the magnitude and not the distribution of the
results is because we canceled the convection effect. In the operating hours of the
building many types of pipes arrangement was examined (parallel and staggered),
and many ratios of ( ) L S and ( ) T S in the ice storage. The study shows that the
staggered arrangement is better for the three types of cooling load and always gives
smaller volume of ice storage. In addition, the study shows that any increase in
( ) L S and ( ) T S cause increasing in the volume of ice storage. In addition, the study
shows that the type of cooling load has great effect on the volume of ice storage.

Stiffness Matrix for Haunched Members With Including Effect of Transverse Shear Deformations

Abbas Abdel-Majid Allawi

Engineering and Technology Journal, 2007, Volume 25, Issue 0, Pages 142-252

This study includes the derivation of the stiffness matrix for a haunched
member using the simple bending theory. The derived stiffness matrix covers
most possible geometric shapes for haunched members under different
loading cases and combinations with including transverse shear deformations
effect. The importance of the transverse shear deformation in haunched
members with high depth to span ratios is shown using numerical example.
The accuracy of the proposed analysis technique is verified by comparing the
results of the numerical example with those obtained from the general
analysis program SAP90 using a large number of subelements.

Effect of Ethanol Concentrations in Internal Coagulant on the Morphology and Separation Performance of Polyethersulfone (PES) Hollow Fiber UF Membranes Prepared by PES/Ethanol/NMP Solution

Qusay Fadhel Alsalhy

Engineering and Technology Journal, 2007, Volume 25, Issue 0, Pages 253-265

Polyethersulfone (PES) hollow fiber UF membranes were fabricated using
ethanol (non-solvent) as additive and N-methyl-2-pyrrolidone (NMP) as a
solvent. Asymmetric hollow fiber UF membranes were spun by wet phase
inversion method from 18 wt.% solids of 18:10:72 (weight ratio) PES/Nonsolvent/
NMP solutions. Effect of ethanol concentrations in internal coagulant
on morphology and separation performance of PES hollow fiber UF
membranes were investigated. UF membranes were characterized in terms of
scanning electron microscope (SEM) while UF experiments were conducted
using polyethylene glycol (PEG10,000 and 20,000 MW), PVP 40,000MW, and
PVA 78,000MW as a solute. It was found that with an increase of ethanol
concentration from 30 to 50 wt.% in the internal coagulant, membrane
internal surfaces were dense and smooth, While the cracks phenomenon was
appear on the internal surfaces of PES hollow fiber membrane with increase
of ethanol concentration up to 100 wt.% (pure ethanol). The external surfaces
for all of the PES membranes are smooth and dense because water is used as
external coagulant; moreover, there is no change observed in the cross-section
of PES hollow fiber with increase of ethanol concentration in the internal
coagulant. Pure water permeation fluxes were decreased from 39 to 23.3
(L/m2hbar) and solutes rejection increased within less than 50 wt.% ethanol
concentration in internal coagulant and then pure water permeation fluxes
increased up to 65.4 (L/m2hbar) and solutes rejection decreased with an
increase of ethanol concentration.

Effects of Mix Property On Time Dependent Behavior of Reinforced Concrete Slabs

A.A.Abdul; Razzak; M. A. Al Jurmaa

Engineering and Technology Journal, 2007, Volume 25, Issue 0, Pages 266-281

A nonlinear, layered, finite element model for predicting the time dependent
behavior of reinforced concrete slabs under sustained transverse loading is
presented. The effects of biaxial creep and shrinkage are considered by using
the provisions of ACI Committee 209. Both elastic- perfectly plastic and strain
hardening plasticity approach have been employed to model the compressive
behavior of the concrete. The yield condition is formulated in terms of twostress
invariants. The movement of the subsequent loading surfaces is
controlled by the hardening rule, which is extrapolated from the uniaxial
stress-strain relationship defined by a parabolic function. Concrete crushing is
a strain controlled phenomenon, which is monitored by a fracture surface
similar to the yield surface. A smeared fixed crack approach is used to model
the behavior of the cracked concrete, coupled with a tensile strength criterion
to predict crack initiation. An attention is given also to the post-cracking shear
strength. The steel is considered either as an elastic perfectly plastic material
or as an elastic-plastic material with linear strain hardening. Steel
reinforcement is assumed to have similar tensile and compressive stress-strain
relationship. A computer program coded in FORTRAN77 language is written
to implement the present study. This program is arranged to give a complete
listing of stresses and deformations in every concrete or steel layer. Several
examples for which experimental results are available are analyzed, using the
proposed model .The comparison showed very good agreement especially for
the maximum deflection, the different about 1%.

Characteristics of Bubbles and Gas Holdup In A Two-Phase Column For Different Liquid Phases

Auroba. Nafaa. Abdullah

Engineering and Technology Journal, 2007, Volume 25, Issue 0, Pages 282-290

Experimental study of gas holdup (Eg), bubble diameter (dvs) interfacial area
(a) m-1, small bubble rise velocity (Ubs), and bubble rise velocity (Ubr) in (0.1m
i.d) and (1.5m) high column operated at ambient temperature and pressure
conditions. The superficial gas velocity (Ug) was varied in the range of (0-0.3)
m/s, spanning both the homogenous and heterogeneous flow regimes. Air was
used as the gas phase.
Different liquids were used as liquid phase (Water, Ethanol, Butanol, paraffin
oil solutions ).
Experimental results shows that the influence of liquid properties on (Eg) is
considerable, where the lower surface tension (s ) gives a lower (Ubr) and
therefore a higher (Eg). High viscosity (mL
) leads to large bubbles and
therefore a low (Eg) and (a) , for coalescence liquids bubble diameter increases
with increasing gas velocity.
A correlation based on dimensionless groups for the predicition of (Eg) liquid
properties is proposed, and found to be in good agreement with the
experimental data.

Study the Integro-Differential Equation in a Lorentzian Energy Spread Case

R. A. Khamis; H. M. Daoud; M. Z. Al-Faiz; M. I. Sanduk

Engineering and Technology Journal, 2007, Volume 25, Issue 0, Pages 291-298

The fundamentals of free electron laser (FEL) theory are now well–established
and can provide a sophisticated description of experiments over a wide range
of parameters. While new technology is being developed for systems working
from 1mm to 10nm wavelengths, the theory remains the same. In this work,
the final consequences of Lorentzian energy distribution in FEL amplifier will
be found by solving of Integro-differential equation using symbolic toolbox
services in MATLAB software v. 6.5 and the relation between several
parameters will be delimited and plotted in order to extract and present the
complex relations between the FEL parameters

3D Wavelet-Based Optical Flow Estimation

Mutaz. S. Abdul Wahab

Engineering and Technology Journal, 2007, Volume 25, Issue 0, Pages 299-311

In this paper, a new algorithm for accurate optical flow estimation using discrete
wavelet approximation is proposed. The image sequences are always assumed to
be noiseless in the computation of optical flow, since there is always a method that
can perform such task. One of the main application areas of the wavelet
transform is that of noise reduction in images. The basic technique is to transform
the noisy input image into a domain, in which the main signal energy is
concentrated into as few coefficients as possible, while the noise energy is
distributed more uniformly over all coefficients. The choice of the transform is
represent an important tool in optical flow estimation. In this paper, several
algorithms of 1-D, 2-D and 3-D wavelet transforms are adapted for the estimation
of optical flow for the first time.

Behavior of High Strength Concrete L-Beams Under Combined Bending and Shear

Omer Q. Aziz; Ferhad R. Karim

Engineering and Technology Journal, 2007, Volume 25, Issue 0, Pages 312-327

This investigation examines experimentally and statistically the behavior
and ultimate strength of L-shape reinforced high strength concrete beams
under combined bending and shear. The experimental investigation consists of
casting and testing of nine beams which were tested under bending and shear.
The effect of compressive strength, longitudinal reinforcement on the load carry
capacity and the effect of transverse reinforcement on the shear strength is
studied. An increase in compressive strength by (65.56%) causes an increase in
load carrying capacity and shear strength at cracking load by (21.47% and
162.9%) respectively. An increase in longitudinal reinforcement ratio for
bending by (153.8%) caused an increase in load carrying capacity by (46.37%)
when the longitudinal reinforcement ratio is kept constant, an increase in
transverse reinforcement index by(59.25% %) causes an increase in shear
strength at ultimate load by (6.55 %).
By using multiple nonlinear stepwise regression method, based on data in
this research and from other literature; equations were proposed for predicting
shear strength at cracking and ultimate loads. These proposed equations show
good agreement and they are conservative when compared with equations given
by Codes of practice.