Iraqi journal of mechanical and material engineering

In this study time series analysis is applied to records of mean inflow to
Bekhme reservoir in the north of Iraq for the period from water year 1933/1934 to
water year 2001/2002. Three Box-Jenkins seasonal multiplicative models are fitted to
this series. These are the (1, 1, 0)x(1, 1, 0)12, (2, 1, 0)x(1, 1, 0)12, and (0, 1, 1)x(0, 1,
1)12 models. The unconditional sum of squares method is used to estimate the
parameters of the models and to compute the sum of squared errors for each of the
fitted model. It is found that the model which corresponds to the minimum sum of
squared errors is the (0, 1, 1)x(0, 1, 1)12 model with moving average parameters θ=
0.378 and Θ= 0.953. The adequacy of this model is checked by plotting the normalized
cumulative periodogram which does not indicate nonrandomness of the residuals.
The 95 and 99 percent confidence regions for the model parameters θ and Θ are shown
graphically. Forecasts of monthly inflow for the period from October, 2002, to
September, 2006 are graphically compared with observed inflows for the same period
and since agreement is very good adequacy of the selected model is confirmed

Effect of non uniform permeability on the operational characteristics of finite
width misaligned self lubricated journal bearing is investigated throughout this work. A
modified boundary conditions for the oil film pressure is obtained by applying integral
momentum equation to the oil film region in the bearing clearance. The performance
characteristics of a misaligned self lubricated journal bearing with slenderness ratio of
unity are obtained for various eccentricity ratios and misalignment angle. The bearing
permeability is changed in radial and circumferential directions. Using self lubricated
bearing with non – uniform permeability enhances the performance of such bearing. An
decreases in maximum pressure and load carrying capacity, attitude angle, and
coefficient of friction. Oil film extent increases with increasing the oil supply pressure.

Experiments have been performed to investigate mixed convection heat transfer
in the thermal and hydrodynamic entrance region of a uniformly heated inclined tube.
The effects of surface heat flux, Reynolds number, the direction of main flow relative
to secondary flow (opposing flow), and angle of tube inclination on the temperature
distribution and local Nusselt number along tube were studied. The study covered
Reynolds number range (450≤ Re ≤2008), and heat flux range (95 ≤ q ≤898) W/m2
,
Rayligt number from 1.1132105
to 3.6982105
and angle of inclination α=0°
(Horizontal), α=30°, α=60° (Inclined), α=90° (Vertical).Results show that the heat
transfer process improve whenever move angle of inclination from vertical position to
horizontal position . The experimental data were correlated for Num as a function of
Ram &Rem for each angle of inclination and then superimposed the angle of inclination
α to give a general equation of average Nusselt number at any α in opposing flow.

The present study deals with an investigation of dry sliding wear behaviour of
grain refined and or modified (Al–20Si) alloy by using a Pin-On-Disc. The refining
was by grain refinements (Ti and B), modification (Sr, Na and P) and combined action
of both (Ti, B + P +chilling). Results indicate that combined grain refined and modified
Al-20Si alloys have microstructures consisting of uniformly distributed α-Al grains,
eutectic Al–silicon and fine primary Si - particles in the interdendritic region. These
alloys (5,6) exhibited better wear resistance (13-15 times) than the same alloy subjected
to only grain refinement or modification (1, 2 and 3) . The improved wear resistances
are related to the refinement of the aluminum grain size, uniform distribution of fine
fibrous eutectic Al–silicon and fine primary Si- particles.

The study immediately aims to prepare technical path to manufacture three
industrial products because of its unavailable in local markets where two of its use for
translating of motion in the lathe machine and one use for translating of motion in an
internal combustion engine where introduce the best percentage loading time(exploit)
on the productivity machine and an addition to calculate of waiting time on it. This
research deals manufacturing that products in the sequencing workshop includes three
productivity machine are (lathe, milling, grinding) where for every machine one
operator with calculates operating time to those products depending upon scientific
rules at any stage of operations machine to arrive the best sequencing which is giving
the total of shorter time to executive an industrial sequencing operations upon productivity machine then those products are testing then dealing by heat treatment and
cooling with special rates to add limited specifications. An effects appear that (CAB) is
an optimal sequencing which finishing productivity cycle with time(129)minutes and
the waiting time(0,33,72) minutes upon productivity machine.

The objective of this research is to study the effect the change of reinforcement
percentage by fibers on the thermal conductivity for polymeric composite material
consist of conbextra epoxy (EP-10) resin reinforced by biaxial woven roving S–type
glass fibers ) ( with density (550 g/cm ٠º-٤٥º 2
) where we used different percentage of
fibers reinforcement to the resin (20%,40%,60%,80%) and studied the influence that on
thermal conductivity for composite material due to this change, and we used Fourier equation to calculate the thermal conductivity coefficient (k),and we used
reinforcement percentages (20%,40%,60%) to reinforced the mechanical tests
specimens to calculated impact strength, tensile strength, flexural strength as illustrated
in diagrams which represent the relation between thermal conductivity coefficient (k)
with temperature and between mechanical properties and reinforcement percentages.

This work aims to prepare a polymer – metallic (composite material) reinforced
by aluminum particles with different grain size and various volume fraction. Using
filing particles from aluminum with a grain size (13 µm), and aluminum dust particles.
This work studies the effect of volume fraction for aluminum particles and predicts its effect on thermal conductivity and impact strength of the prepared composite material.
The results show that the thermal conductivity of a material reinforced by aluminum
particles (filings) increases as the volume - fraction increases, where it reaches (4.85
W/mm.K) at volume – fraction (9.2 %), whereas in composite material reinforced by
aluminum dust, the thermal conductivity increases to reach (4.74 W/mm.K) at volume –
fraction (2.2 %) and then decrease to (4.38 W/mm.K ) at volume fraction ( 4.7% ) and
then stable at limited ratio from volume fraction.
Also the results show that the mechanical impact resistance for composite materials by
dust particle increases as the volume – fraction – particle increases, where it reaches
(81.25 kJ/m2
) at volume fraction ( 9.2% ). whereas composite materials reinforced with
aluminum particle (filing) also increase as volume – fraction increases, but, as little as
the increasing of composite materials reinforced by dust where reachs (63.158 kJ/m2
)
at volume fraction ( 9.2 % )

This paper illustrates the analysis and simulation of narrow band antenna arrays
with adapted radiation pattern using digital beamformation. The technique used for the
system is the Shifted Sideband Beamformer (SSB). This paper analyzes the stages of
the receiver and presents a model for simulation. The SSB was chosen because it
exhibits moderate complexity and storage requirement. Different spatial filters such as
Uniform weight, Blackman-Harris, Tylor, and Dolph-Chebyshev were used to control
the side lobe level of the arrays. This paper also shows how to implement null steering
procedure to circumvent the jamming and high interference angles. Only the linear and
two dimensional arrays were taken into consideration.

In this work, the performance of a class of asymmetric turbo codes, which are
composed of mixed types of non-identical, recursive systematic convolutional codes
has been investigated.
Internal pilot insertion technique is utilized to further improve the BER performance of
turbo code especially at high SNR. The minimum distance of turbo codes and the
multiplicity of low weight codewords can be improved by inserting pilot bits within the
sequence of information bits entering the turbo encoder. This technique was shown to
be useful on the symmetric and asymmetric turbo coded signa

Servo systems are indispensable in modern industry. For example, they are
widely used in robotics, electrical vehicles and automated factories. Therefore, the
study of the stability of the system and its response to linear and nonlinear elements is
an important control system problem. This paper focuses on determination of servo
system transfer function and the effect of the main nonlinearities on its stability by
developing an algorithm for the system and simulating using MATLAB. The algorithm
used is the describing function algorithm and its analysis ,since it is one of the methods
used to analyze nonlinear systems stability.

Human as researchable organism of information , collecting it , for the most
important thing discerning him , by creating special system in his environment.
The research problem appears through two sides, the first relates with the human
and his , her existing and institutional belonging as individual and society , the second
relates with the degree of relation between the evolutionary nature through life , and the
suitable physical evaluation according to life dynamic.
In order to cure the research problem for reaching the results , the research
depends on a hypothesis , that the evolutionary value of human relates with human
thinking’s , his environment through , regionalism, tertian, norms characters and norms,
in order to create architectural system according to evolutionary values with parallel to
the evolution of the human .
The research depend on analytics methodology stands on the theories through that
attitude , for the societies the evolutionary condition affects the type of architecture
production.
The research reaches to the most important results that the evolution of societies
affects the type of architecture according to two directions;
- , first , relates with human thinking evolution . - second , relates with human and his instructional containing and the demographic
growth , that affects the societies and architecture from the other side.

Town development is one of the major priorities that make societies depend on in order
to build suitable environment for human and societies needs.The strategies differ about city developing , some of them relate with natural
ingredients , according to its sources , as potential forces , on the other hand there is
artificial , can be as attractive poles , for town developing with in hierarchy of levels.
The researchproblem appearswithin the mechanism of the city development according
to investment policy ,depending on tourism through the researchable sample of Hilla
town , as case study, as part of the total development of the country, as part of the
international system. The research used a hypothesis, that city development stand on
activate more affective poles in order to discover and activate it, for town contains
many related poles, every one depends on the other. Investment is one of the major
mechanisms for their activation.
In order to reach the research results, the analytical methodology, depended on
descriptive phrase used to analyze the poles in the case study.
The research reached through the case study, that the town development affected by the
existence of the poles, the degree of their relation, and their interaction, with a
mechanism, make investment as an important side in the poles activation, and the town
developing on the other hand.