Print ISSN: 1681-6900

Online ISSN: 2412-0758

Volume 25, Issue 1

Volume 25, Issue 1, March 2007, Page 1-131


Study of 2-D Laminar Flow In A pipe With A sudden Contraction of Cross Sectional Area

Khudheyer S. Mushate

Engineering and Technology Journal, 2007, Volume 25, Issue 1, Pages 1-8

Abstract
The paper presents a detailed numerical study of laminar flow in a pipe with sudden
contraction in its cross sectional area. A computer program has been developed to analyze the
laminar flow field in the pipe-sudden contraction configuration. The Navier-Stockes and
energy equations are solved using primitive variables with a finite -volume (FV) solution
method. The study was carried out for a Reynolds numbers range up to 750 and for different
contraction ratios (d/D). The results demonstrate that the separation regions increase with the
increase of Reynolds numbers. And the contraction ratio (d/D) has significant effect on these
regions.

Parametric Study On The Effect Of The Fiber Reinforced Polymer(FRP) Pad On The Stress Intensity Factor of A Cracked Pipe

Wail N.Al-Rifaie; Waleed Khalil Ahmed

Engineering and Technology Journal, 2007, Volume 25, Issue 1, Pages 9-24

In this paper the effect of using FRP bonded pad to reinforce damaged pipes
subjected to internal pressure is investigated. Outer Longitudinal edge crack
was simulated by using standard finite element method as a powerful tool for
the numerical solution of a wide range of engineering problems. Cracks in the
present study are investigated by using linear elastic fracture mechanics in
order to calculate the stress intensity factor SIF. Mode I SIF was calculated by
means of using standard FE program ANSYS5.4 and the element used was 8-
node quadrilateral isoparametric element .A parametric study was done to
investigate the effect of the pad width W, thickness H and the volume fraction
Vf of the composite pad on the SIF of the cracked pipe .It was found that by
using FRP pad to reinforce the cracked pipes , the SIF reduces in the vicinity
of the crack tip, and the fiber volume fraction of the pad has a great influence
on the SIF.

Thermal Initiation of methylmethacrylate by Methoxy–oxo- bis [N-(4- bromophenyl) Salicylideneiminato] Vanadium (V)

Najat J.Saleh

Engineering and Technology Journal, 2007, Volume 25, Issue 1, Pages 25-35

Methoxy – oxo - bis [N - (4-bromophenyl ) Salicylidene – iminato ] Vanadium
(V) : [VO (Br C6 H4 N : C H O C6 H4 )2 OCH3 can initiate methylmethacrylate
thermally at 80°C . Under the experimental conditions employed, no
retardation or inhibition is observed. The order with respect to the initiator
concentration is (0.5), while the order with respect to monomer concentration
is (1.8) which gives an indication that the rate of initiation is dependent on
monomer concentration.
Spectroscopic studies suggest that during the thermal polymerization a
reduction in the oxidation state of vanadium occurs with heterolytic scission of
the V- OCH3 bond and this might be induced by MMA molecule which forms
intermediate complex between VOL2 OCH3 and methyl methacrylate
monomer before the formation of the primary radical responsible for the
initiation process.
Activation energies of polymerization as well as initiation processes in the
present system were also determined . The tacticity of polymer produced is
examined.
According to the experimental results obtained a mechanism of thermal
initiation reaction is proposed.

Finite Element Analysis of the Rake Angle Effects on Residual Stresses in a Machined Layer

Maan Aabid Tawfiq

Engineering and Technology Journal, 2007, Volume 25, Issue 1, Pages 36-48

In this paper, a plane strain Finite Element Method is developed and applied to model and
simulate the orthogonal metal cutting of (AISI 1045 St) with continuous chip formation.
Seven sets of simulation results for cutting with rake angles (-15o, -10o, -5o, 0o, 5o, 10 o and
15o), are summarized and compared to analyze their effects in the cutting process in steady
state condition. Simulation results of the residual stresses below the machined layer are
presented and compared with other papers in the literature and showed good agreement.
Simulation results offer an insight into residual stresses through different values of rake
angles. Based on simulation results, characteristics of residual stress distribution can be
controlled by optimizing the rake angle. The simulated results show that for positive rake
angles and position, the zero of maximum effective stress is found to be at (0.04) mm
beneath the work piece surface, while for negative rake angles, the position of maximum
effective stress is changed to be directly on the workpiece surface.

Electrical and Photovoltaic Properties of In-pSi Contact

Khalid Z. Yahya

Engineering and Technology Journal, 2007, Volume 25, Issue 1, Pages 49-55

In the present work, the electrical and photovoltaic properties of In-pSi
contact were investigated for the first time. Two creditable methods were used
to determine the value of barrier height for this contact. Experimental results
shows a reasonable agreement with the simple Schottcky-Mott theory. The
contact shows good response to white light when it works under bias
condition. Peak response of 0.22 A/W at 850 nm wavelength was registered.

NC Roughing Machining of Cavities Defined by Surface of Revolution Approach

Wissam K. Hamdan

Engineering and Technology Journal, 2007, Volume 25, Issue 1, Pages 56-77

In the NC roughing phase of cavities, process planar needs to find the
machining layers as well as the feasible cutters for these layers. This Paper
deals with the issues of Cavity Construction based on Surface of revolution
technique using cubic Bezier curve as a generator curve. First the generator
curve is constructed in x-z plane then allowing it to revolve through 360o
about z-axis in order to generate the required surface cavity. A strategy of
Maximum (critical cutter size) and Machining layers determination is also
introduced in this paper. Numerical iteration is used for this purpose using
MATLAB programming system to reduce the computational time. A
comparison is made between different machining cavities critical cutter size
and using cutters smaller than the critical size showing a wide reduction in
the length of circular tool path(s) (CL) and the volume of removed metal
(VRM).Numerical examples are presented to illustrate the proposed system.

Mixed Convection in The Entry Region of a Vertical Annulus with a Constant Temperature Rotating Inner Cylinder

Akeel A. Mohammed

Engineering and Technology Journal, 2007, Volume 25, Issue 1, Pages 78-96

Laminar air flow combined convection in a vertical annulus with a constant
temperature rotating inner cylinder is treated on the basis of a developing flow
model, and the basic differential equations are rewritten in finite difference form
and solved by a computer program in Fortran. Investigation covers the
ranges of 0.2≤N≤0.9 , –300≤Gr/Re≤800 and 0.2≤Re2/Ta≤1000. In addition to the
usual heat transfer calculations, this enables the developing velocity and
temperature fields to be studied. On the other hand , the effect of a superimposed
aiding or opposing natural convection on the developing tangential velocity
profile is also investigated.

Effect Of Solid Catalyst On Bubble Rise Velocity And Gas- Drift Flux In Three-Phase-Columns

Kamal Mohammad Ahmad

Engineering and Technology Journal, 2007, Volume 25, Issue 1, Pages 97-102

The bubble rise velocity and drift flux were measured in 0.051 m i.d glass
column with ethanol as the liquid phase, cobalt catalyst as the solid phase in
concentration varying from (1.0 to 0.4) vol % in three phase column.
Gas superficial velocity (Ug) was varied from (0.02 to 0.1) m/s.
Experimental results show that the gas-holdup and gas flux decreases with the
increasing of catalyst concentration but increasing bubble rise velocity.

Early Manufacturing Cost Estimate For Mechanical Parts

Khalid Karam Abd

Engineering and Technology Journal, 2007, Volume 25, Issue 1, Pages 103-116

In manufacturing environment cost estimates process is made in all stages of
product development from research to final product. Good estimating
techniques and procedures are necessary for each manufacturing stage. When
properly implemented, these techniques produce acceptable operational
estimates that are useful to management for decision-making.
In this research, an algorithm is developed to build system is called
FBMCE (Feature-Based Manufacturing Cost Estimate) to incorporate making
decisions integrating design, process planning and manufacturing for cost
estimate purposes. The FBMCE system has been tested on product (Shaft 8E -
200) in State Company for Electrical Industries and showed promising results.

Grillage Analysis of Plates for Vibration and Stability

Ammar A. Ali; Sabih Z. Al-Sarraf

Engineering and Technology Journal, 2007, Volume 25, Issue 1, Pages 117-131

This study deals with the problem of approximating the dynamic and static
analysis of plates by using equivalent grid-framework model. The emphasis, for
plate analysis, is on the stability and vibration analysis. Numerical results are
presented for many example problems, and they indicate that the adopted method is
reasonably accurate. For vibration analysis of plates using beam-column analogy
the percentage of error is depends on mesh size.

Effect of Possivity on The Mechanical Machined Surfaces

Engineering and Technology Journal, 2007, Volume 25, Issue 1, Pages 1-8

The object of this research is to study the passivity of parts surfaces
produced from steel and its alloy. The study steps include, preparing
specimens of low carbon steel ,with (dimension (20*30 cm) and its thickness (2
mm)). The specimens were immersed in a solution containing the following:
1. Caustic soda.
2. Sodium nitrate (1%)
3. Sodium cyanide (1.5%)
4. Sodium chromate (1.5%)
The influence of caustic soda concentrations, temperature of solution and
time of immersing on corrosion of specimens were studied, from which it has
been shown that it was possible to obtain the best passive surfaces of the parts
with caustic soda concentration (5%), time of immersing specimens (20 min)
and temperature of solution (45oC).
The results and conclusions obtained from this study were applied to treating
surfaces of some machining parts in Nasser State Company/central tool room
plan. The results show noticeable improvement in the corrosion resistance of
the metal used for more than 70 days.

Design Effect of The Welded Joints On Fatigue Strength For Low Carbon Steel Metal (ST- 52- 3)

Engineering and Technology Journal, 2007, Volume 25, Issue 1, Pages 9-22

ومقارنتهم مع المعدن (UU,U,VV,V) إن هدف البحث الحالي هو لتقيم أفضل وصلة لحام للأنواع
والذي يستعمل على نطاق واسع في الصناعة. ومن ثم بيان تا ثير هذه (ST-52- الأساس نوع ( 3
الأنواع على حد الكلال تحت تأثيرالاحمال الانحنائية المتعاكسة.
بينت نتائج الفحوصات العملية لهذه الأنواع الأربعة من وصلات اللحام إن مقاومة الكلال للنماذج
الملحومة تكون مقاربة جدا لمقاومة الكلال للمعدن الأساس. وأكثر دقة فان الفرق مابين هذه
٤,٥ و٪ ٥) وبترتيبهم على أساس ٪ ,٤,٢٪ , الوصلات الملحومة والمعدن الأساسي هو( ٪ ٣,٧
على التوالي. (UU وأخيرا VV,V,U ) الجودة (الأفضلية ) فسيكونون