Iraqi journal of mechanical and material engineering

The objective of this study is to relate the quality of concrete production to the
capability of the production process in such a way that the process capability could indicate
the level of production quality in batching plants. The main idea in this research is that the
accepting and refusing lab tests are not sufficient as quality indices and that the statically
analysis including control charts and capability calculations give biter image to the
performance levels of production process in batching plants . In this study, the production
conditions for a batching plant are investigated and the supervision is taken as the effecting
factor on the quality. Large number of testing data of compressive strength are analyzed.
Results showed that it is necessary to use more detailed procedure than accepting and
refusing concrete tests.

The aim of the present investigation is to study the effect of different simulated solutions on
wear behavior, chemical properties and ion release of Ti-6Al-4V alloy which used in human
body. For this purpose three solutions have been used (Hank\'s solution, 0.9NaCl and
artificial saliva). The corrosion properties of Ti-6Al-4V implant alloy were examined at
37ºC by using electrochemical techniques, such as the potentiodynamic method and open
circuit potential (OCP). The electrochemical corrosion characteristics of Ti-6Al-4V implant
alloys in three biological solutions were measured in terms of the corrosion potential (Ecorr)
and the corrosion current density (icorr ).Wear behavior was investigated by using pin-ondisc
tribometers at human temperature under different loads (10,15,20)N. The wear test
consisted of measuring the weight loss of samples. The metal ion release of base and
alloying element by immersed specimens into various solutions for 7 days (168 hours) at
37ºC. The result found that the Ti6Al4V implant alloy in three biological solutions exhibited
a characteristic of a good behavior. The superior corrosion resistance these alloy which
current density measured in (nA/cm
2
). The weight loss of samples by wear test increase with
increase load and time. After applied heat treatment, about 40% enhancement in the wear
behavior of alloy. The quantity of Al element metal release of implant alloy with variation
fluids which increase with decrease the value of pH and little amount of vanadium element
in hank\'s solution.

Experimental work has been conducted using silica oxide SiO2 nanoparticle as an
additive to diesel fuel in a compression ignition engine in order to reduce pollutants
emissions and to improve engine performance. A 10 ppm and 20 ppm of SiO2 nanoparticle
is added to the diesel fuel. The results showed that the SiO2 nanoparticle blended with diesel
fuel improve engine performance such as brake thermal efficiency and brake specific fuel
consumption, increase in exhaust gas temperature and reduces carbon monoxide, and
unburned hydrocarbon emissions. Also the results showed that the blend of the SiO2
nanoparticle to diesel fuel led to increase in the carbon dioxide in the exhaust gases. The
tests are carried out at constant speed of 1500 rpm, under different engine load conditions.

The research deals the evaluation of buckling behavior for 5056-H18 Al alloy columns
under variable loads and studies the effect of initial deflection on the critical buckling load.
Seven samples were used for the purpose of testing the buckling of the column. The critical
deflection of the column can be determined by measuring a length multiplied by 0.01 and
this is the critical load of the columns. For the purpose of measuring the critical deviation of
the column, a digital dial gauge has been applied and it set at 0.7 distance from the length of
the column from the fixed condition. The experimental results were compared with the
Perry - Robertson formula, Euler\'s theory for long columns and with the values calculated
from the ANSYS 17 program. It has been observed that the Euler formula showed good
compatibility with the practical results with safety factor 1.5. The ANSYS results showed
well agreement taking a 1.5 factor of safety. While the Perry-Robertson formula needs a 1.4
safety factor to be safe results compared with experimental results.

The introduction of polymeric blend-based nanomaterials has encouraged the development
of flexible nanocomposites for structural applications in need of superior mechanical,
performance. In current research, three groups of polystyrene blend-based nanocomposites
samples were fabricated by melting technique using a twin-screw extruder. These samples
consist of polymer blend (polystyrene (PS): 1% copolymer (polystyrene (PS)-co- maleic
anhydride (MA)): 3%ABS) as a matrix material, was strengthen by three different type of
powders in nanometer size (silica (SiO2), cement kiln dust (CKD) and Fly ash (FA))
individually, with selected weight ratio (0, 0.2, 0.4, 0.6 & 0.8 wt. %) for each of them.
Experimental investigation was carried out for tensile properties and fatigue strength besides
FTIR test and morphology analyzing of fracture surfaces by SEM. The results showed that
tensile strength values and modulus of elasticity increased as the nanoparticle content in
composite increased, but according to specific percentages of nanoparticle content in the
composites samples, for three groups of the prepared nanocomposites samples. Moreover,
the fatigue test revealed the super-improvement in the fatigue properties of the selected
hybrid nanocomposites samples, as compared with neat polystyrene and polymer blend (PS:
1% (PS-co-MA): 3% ABS) and fatigue limit was apparent for all types of hybrid
nanocomposites materials produced in this work. Morphology of the fracture surface was
showed a homogeneous structure formation for optimal samples of each group of
composites, indicating a good compatibility between the component materials of polymer
blend and the reinforcement nanoparticles.

Multi-point forming (MPF) is a new flexible forming technology in which the fixed shape of conventional dies is replaced by a pair of opposed matrices of movable punch elements called \"punch group\".By using multi-point die a variety of three dimensional sheet parts of different shapes can be produced. However due to the discrete contacts between the work piece and punches the dimple defects occurred. In this paper, B-spline technique was used to represent the profile of the final product shape by adjusting the punch height of reconfigurable die. Finite element code (ANSYS 11) was used to simulate the MPF process and to investigate the influence of punch tip radius the interpolator type on the stress distribution, thickness variation and dimpling defect .The simulation results show that the large tip radius and (4mm) rubber interpolator have a great effect in reducing the stress concentration, thickness variation and also prevent the dimpling defect.

In this study metal matrix composite (AMMS) was
successfully manufactured using stir casting route. The influence of
content on microstructure, electrical properties and wear
resistance were investigated . The microstructure of composite revealed that
homogeneity of particles in the matrix and also the reinforcement of
grains compared to matrix grains. The homogeneity and reinforcement can be
attributed to enhance the electrical and wear properties and this perhaps could
due to efficiency of stirring process during the casting. The
content shifted the conductivity and permittivity from reducing in matrix to
increasing in the composite when the frequency increased. The wear resistance
was improved due to addition of compared to matrix.

Around the world about millions of people using the medical devices or biomaterials
that implanted in side human body in order to replace the function of unwell tissues or
damaged parts. In spite of the importance roles of these implants in saving or improving
human life, many of them are failed during short period or having complications. The main
failure of the biomaterials caused by unqualified biocompatibility. Thus there are two
materials types used for this field investment such as thin film nitinol and stainless steel.
Stainless-Steel type 316L are widely used in biomaterial bone applications specially fixing
devices such as plates, screws, pins and artificial joints. On the other hands, thin film nitinol
indicates a high possibility for applying in a small new vascular devices like heart valves
and covering stent grafts because of the singular beneficial properties of this material like
super-elasticity and low-profile feature.

In this study ,the adsorption of an industrial blue dye was investigated by using
pomegranate peel in different size . The effect of the process parameters such as , contact time
; adsorbate concentration pH) and (temperature ) are reported . \\"Nearly 2-3 hr of contact time
are found to be sufficient for the adsorption to reach equilibrium\\" (Abetter fixation was
obtained at acidic pH (2) and room temperature 25◦C.