Iraqi journal of mechanical and material engineering

Steel sandwich structures with honeycomb and corrugated cellular cores have demonstrated
the capability of supporting significant static bending loads while also enabling effective
mitigation of impulse loads, the main objectives to use these structures is weight reduction
and isolate or reduce the deflection and stress. This research aims to study the effect of
dynamic load on the dynamic properties of various types of sandwich cores then find the
best model that withstand high stresses and dissipate loads with less mass was possible. The
studied model of sandwich is of dimensions (500x500x100) mm with five cells. Four types
of steel sandwich plate (SSP) finite element models of various core types have been created:
(1) triangle corrugated core, (2) trapezoid corrugated core, (3) square honeycomb and (4)
out-of plane hexagonal honeycomb, the mass of various types was constant with value of
13.75 kg. The SSP types were compared by using ANSYS (15.0) APDL software.The finite
element models are examined under the effect of transient concentrated stepped load of
(350N) during 10ms. The time history response showed that the minimum von-Mises stress
and minimum deflection occur at triangle corrugated SSP with values of stress (12.5Mpa)
and deflection (3.8????????), but in energy absorption the square honeycomb is the best type with
reduction of stress (99.65%) and reduction of deflection of (98.95%).

Vegetable oil has been investigated to displace products which are derived from
petroleum because of its environmentally-safe properties and has become a vital source for
bio-lubricants. Vegetable oil availability as one of the renewable sources is one of the
usefulness of it. Additionally, the vegetable oils based lubricant has indicated the potentials
for reducing carbon dioxide and hydrocarbon emission while operating in internal
combustion engines and in industrial processes. In this study, the mustard seeds oil was
investigated to study its lubricant characteristics under different loads while comparing it
with commercial lubricant using a pin-on-disk tribometer. The whole experiential works
were corresponding to American Society for Testing and Materials (ASTM G99).Under low
load, the results exhibit that the mustard seeds oil shows adequate tribological characteristics
compared to other petroleum oil samples. In conclusion, the mustard seeds oil has a better
wear and friction resistance. Therefore, mustard seeds oil can be used for lubrication of
mating components.

Many face organs are exposed to different environmental conditions in terms of different of
ambient temperature, degradation, discoloration, changes in humidity and especially
frequent washing of these organs. These conditions cause changes in the structure of
materials so, for restoring the function and improving aesthetics of the affected areas of
maxillofacial by surgical reconstruction and prosthetic rehabilitation the silicone rubbers
(SR) and PMMA are the materials of choice. So that, the aim of this research is to
investigate the effect of addition of polymethyl methacrylate (PMMA) material on the
physical properties of blends from SR/PMMA at different weight percentage (5%, 10%,
15% and 20%) of PMMA to silicone rubber. Fourier transform infrared spectrometer test )
FTIR(, density, water absorption and thermal properties were done on the all prepared
samples, which are used for maxillofacial prostheses applications. The results showed that
there is good correlation in FTIR spectrum for reference silicone rubber and (SR/PMMA)
polymer blend and this confer a good compatibility between silicone rubber matrix material
and PMMA. As well as the physical properties showed that the favorite percent of PMMA is
10% which has ideal characteristic. So, this sample may be a suitable material to achieve the
properties required for maxillofacial prosthetic applications

In this study, a branched GAX absorption cycle operating with NH3-H2O pair has been investigated to assess its performance under steady state conditions. The cycle modeling is implemented using Engineering Equation Solver (EES) software. Analysis includes equations of mass, species and energy conservation. The analysis is used to simulate a GAX absorption chiller utilization for air conditioning applications with a nominal capacity of 95 TR. This chiller uses solar collectors as heat source. The operating parameters are selected at different values of the heat source temperature (140 - 185°C), condenser exit temperature (30 to 48°C), evaporator exit temperature (2 to 11°C) ; split ratio (0 to 0.18); the difference in ammonia concentration(0.25-036), mass flow rate in solution pump mr=1 kg/s; heat exchanger effectiveness   0.8. The results showed that the average COP is sensitive to operating conditions where the average COP and cooling capacity of the branched GAX absorption chiller increase with increasing generator and evaporator temperature whereas they decrease with increasing condenser temperature. Simulation results also show that the split ratio and ammonia concentration difference have a significant impact on the performance of absorption chiller

Recent discoveries of petroleum and gas reserves in environments with severe operational
conditions metallic materials, carbon and low alloy steels, have pushed and prompted the
need to find alternatives. The presence of gaseous hydrogen may cause the suffering of
hydrogen damage and embrittlement. The effect of hydrogen and temperature on fatigue life
properties, have pushed the utilization of steel procurement specification even stricter than
they used to be. The main modifications concern the mechanical resistance, toughness at low
temperatures weld ability and resistance to embrittlement related to hydrogen.
Aiming to enhance the reliability and operation of pipelines system, a study based on the
elastoplastic fracture was carried out to determine high level prediction for the fatigue life,
as well as to evidence the toughness resistance of the used materials. The materials tested
here are API 5L X70 and X100 micro alloyed steels. Hydrogen had affecting the material
properties, which are reducing the toughness and an influence spotted in Charpy tests

This paper present a mathematical study on drag reduction by polymer additive such
as poly isobutylene (PIB) with kerosene in turbulent pipe flow by using computational fluid
dynamic commercial package program (COMSOL 4.4) solution. Theoretically the
computational study was used to calculate the pressure drop in two dimensions geometric
model with 6m length and 80 mm width as a diameter of the pipe, Geometric shape has been
drawing by tools of the program windows, and to simulated the flow region mathematically
the flow region is divide into very small parts (mesh generation). The model that used in the
mathematical modelling method was (k-ɛ( mathematical turbulent model to study the
internal pipe flow properties. The continuity and momentum equations and two k-ɛ model
equations have been solved by the program to obtain the theoretical results. There variables
that used in the theoretical study were effective density, effective viscosity, inlet velocity,
and outlet pressure. The boundary condition was inlet and outlet velocity, temperature, and
pressure of flow, and the velocity (u=0) at the pipe wall. The theoretical calculations show
that the velocity and drag reduction percentage increases with polymer concentration and
volume flow rate increasing where maximum DR% is 15.8% at volume flow rate 500 ℓ⁄min
with polymer concentration 100 ppm, pressure drop decreases with polymer concentration
increasing. Friction factor decreases with polymer concentration increased, also shear stress
decrease with polymer concentration increasing.

The alloy of nickel aluminum bronze (NAB) presents superior properties such as high
strength, excellent wear resistance and corrosion resistance, so it’s used in a wide range of
engineering applications. Usually, this material undergo to a series of machining processes
to achieve the final shape. In this paper, NAB alloy reinforced with cubic boron nitride
(CBN) particles was fabricated by powder metallurgy route. Design of experiments has been
used to study the effect of main turning parameters on the main cutting force for NAB-CBN
composite. Numerical modelling was developed to predict the main cutting force required
during turning process under different machining conditions. The results of numerical model
showed that the maximum error comparing with the experiment results is not exceed
13.86%, which suggests that the developed model are reasonable. Optimization of
machining process parameters was done using response surface method.

Super plasticity behavior finds applications in so many fields, for example the aerospace
manufacturing that is the main bazaar for super plasticity, but automotive, medical, sports,
cookware and architectural applications have their share too. \"In this work a study of the
superplastic behavior of a new Zn-Al alloy was conducted. In addition to the investigation of
the possible superplastic behavior of Zn-0.5Al alloy. These alloys were prepared by using
gravity and chill casting techniques. Zn-0.5Al alloy was subjected to hot rolling at 250 ºC
and cold rolling at room temperature, while Zn-48Al alloy was also hot rolled at 250 ºC to
20% reduction in the thickness of sample followed by partial remelting at 500 ºC. Several
tests were carried out such as physical, mechanical and chemical which include (XRF, XRD,
OP, SEM, Microhardness (HV) and Tensile (cold, hot) test). Results showed that the\"Zn0.5Al alloy has poor mechanical properties and may not be regarded as a superplastic alloy
compared with Zn-48Al alloy. The Zn-48Al alloy generally enhanced all properties. The
maximum elongation of (450%) was obtained in Zn-48Al alloy after thermomechanical
controlling process and partial remelting.

The structures of a sandwich composite have been utilized in the aerospace industry and
engineering applications. Prediction of a theoretical composite construction\'s flexural
properties is important for efficient composite products design. In this investigation, four
different core shapes were used in the fabrication of the sandwich frames with constant
volume of sandwich composite structure in each case; these are hexagonal, rectangular,
triangular and circular. The effect of core stiffeners number was studied to finding the best
stiffeners number which gives the highest properties in strength using the finite element
analysis.
The material of the each face sheet is consisting from epoxy with four layers of a woven
fiberglass laminate construction, and the core stiffener material consists from epoxy matrix
with carbon fiber, the fiber volume fraction was 60% for both skins and core composites.
The analysis of the three point bending load with a value of (10 kN) conducted by
constructing a finite element model, explained that the best shape of core was rectangular
which give less deflection value of (11.939 mm) from the other shapes, for the same
properties of material and constant core volume in each case. Also, it was determined the
optimum stiffeners number, for the rectangular core, was five stiffeners in longitudinal
direction and twelve stiffeners in transverse direction, gives strengthen structure

The available huge amount of solar radiation in Iraq all over the year can be regarded as a
useful energy source. It can be utilized to generate electrical energy using PV panel’s power
plants. Therefore, it is important to recognize the behavior of these PV Panels through the
year with changing in amount of the solar radiation and weather temperature. The monthly
average (daily and hourly) of extraterrestrial, global, diffused, and beam radiation, with PV
panel’s temperature and electrical efficiency of different tilt angle is studied in three Iraqi’s
cities. The results indicated that the total radiation ranges are greater in Karbala than
Samarra and Basra cities; despite of the extraterrestrial radiation in Basra higher value than
Samarra and Karbala cities. The higher magnitude in the monthly average solar radiation in
any city is not necessarily best location for construction PV power plant, because the
electrical performance of PV panels is affected by its temperature. Rising in temperature led
to drop in the PV panel’s efficiency.

Cellular manufacturing system is the nerve of industry in our days and many studies
and researches discussed in this field . In this research row materials need to cross long
distance about thousand meters during the manufacturing process to be final product in
ALWAZIRIA ELECRICAL MOTOR FACTORY the problem was needed to reduce the
routing of row material flow and increase flexibility with saving same operation sequence .
First segmented the facility into subsystems called cells and figured the system output .the
research goes in two ways first assign the problem and parameter affected on production
process secondly apply the particle swarm to the problem after writing the algorithms. The
particle swarm technique shows great flexibility in scheduling purposes problem. Also the
product will cross about 400 m instead of 1000 m before using PSO after extracted the
result which it discussed and recommended to the future researcher .