Al-Qadisiyah Journal for Engineering Sciences

The big water deficit of Taiz city represents necessity to look for a nearby location that has suitable features for constructing a desalinating station and as that the misdirected condensers heat of Mokha steam electrical station, which is located near water source (seawater) represent the main factor can be exploited in the desalination of the city of Taiz.
The work aims to: Choose a site for the desalination plant for the city of Taiz and then conduct a comprehensive study of the site to determine its suitability. choose the best source of thermal and electrical energy as possible in the site in order for us choose the most appropriate system That comply with the power source and then conduct a comprehensive study of the selected energy source to determine the its characteristics to make sure The authenticity of the our selection to him. Finally determine the amount of benefit from the misdirected heat condensers for steam station Mokha in desalination
The concluding results have indicated that:
 The basic advantages of the location are the required. The best decision for constructing desalinating system is by evaporation that is multi-effects by using solar collectors as a source of the energy in combination with the Heat condensers for steam station and who will claim to achieve the best return on practical and economic system.
 The properties of solar radiation in an excellent location, which confirms the correctness of our choice of source and qualifies Site to thermal power generation.
 The misdirected condenser heat of Mokha electric steam station equals 41 Co. Which means that it is possible to make use of it to desalinate water with a productivity of 10000 M3/ day for Taiz city. It will help to raise the nutrition water temperature which will lead to: reduce the number of phases of the system from 5 to 3 , which reduce construction costs and also maintenance and operation as well will work to reduce the necessary heat for thermal exchange inside condenser by 25% that would raise the efficiency of multi-effect desalination system.

Brass is alloys of copper consisting mainly of copper and zinc, and it is welded in the same general
manner as copper, but because of the peculiar properties of the alloying metals zinc, it is that must
receive certain variation in welding. And because of viral application as structural materials in
industries, in this work the weight losses method used to study the general corrosion behavior of ????
– Brass (Cu – 37 Zn) alloy weldments were welded by Oxygen – Acetylene mixture with three
types of filler rods, ???? – Brass, ???? – ???? Brass and Tin – brass in sulfuric acid and sodium hydroxide
solution at room–temperature (298k),where also the microstructure of these weldments before and
after corrosion was studied. The results obtained shows that the acidic medium is more aggressive
than alkaline medium for the three weldments and the total corrosion rate for three types of
weldments in acidic medium was (0.085155 MPY) which was more than from alkaline medium
total corrosion rate (0.030745MPY) for the same wldments, it is also found that longer exposure
time to corrosion medium, leads to a lower corrosion rate while weight loss is still increasing.

The viscosity at different temperature are measured for some Iraqi wells, A mathematical model was
proposed to describe the viscosity as a function of temperature depending on the experimental results ,
All the samples were collected from storage tanks of the following sites: South of Al Rumeela, North
of Al Rumeela, Al Halfaya and Bozorgan. The results give good agreement with the experimental
result that was measured for Iraqi wells, where the maximum average percentage of error was 7.4 % ,
the maximum AAD% was 4.4% and the maximum SD was 0.49013%.

This paper numerically investigates laminar mixed convection flow through an octagonal cavity
enclosure where four cases with different positions and directions of its lid-driven were simulated.
The lid-driven moves in horizontal rightward and leftward on its upper wall in the first and second
cases while it moves vertical upward and downward on its right side wall in the others cases. The
numerical study was carried out by solving the governing equations (continuity, momentum and
energy), and applying the tri-diagonal matrix algorithm (TDMA) method via ANSYS 11.0
program. Four of the eight external walls of the octagonal cavity enclosure are insulation walls and
the other four walls were classified into two hot and two cold walls. The mixed convection flow
and heat transfer characteristics through isotherms, streamlines and the average Nusselt number
were considered based on different Richardson numbers (Ri = 0.01, 1, and 10). The results
demonstrated that heat transfer mechanism, the flow pattern and formation of vortices are
significantly dependent on values of the Richardson number. Within the enclosure, the lid-driven
movements showed an improvement in the heat transfer rate where the direction of the sliding wall
considerably affected the flow and temperature distributions for all values of the Richardson
number. The Nusselt number of the lid-driven increased from 50 with the upward motion to 55 (10
% increase rate) with the downward motion counterpart, and increased from 12 to 17 (40 %
increase rate) with the rightward and the leftward motions, respectively.

This paper concentrates on the application of genetic algorithm optimization technique to find the gear
teeth numbers for six-velocity Lepelletier automatic transmission with given approximate velocity
ratios and a set of design constraints. MATLAB is employed to find the gear teeth numbers and the
velocity ratios satisfying the design and geometric constraints.

In the last four decades, the car body thickness has reduced significantly from almost 1.5 mm to
below 0.5 mm. This was mainly due to the demand for weight reduction for saving more fuel cost.
Besides being thinner, maintaining the high strength of car body was possible by using a newly
developed high-strength steel thin plate. However, mechanical properties of bulk materials which
usually tested using a standard big size sample are not necessarily representing the actual properties
of the material when dealing with very thin and small size components. This drives the research on
the mechanical properties of the micro-sized specimen for the production of tiny metal-based
components. In this study, tensile and fracture behaviors of the micro-sized specimen were
investigated. The materials used were 100 and 300 micron stainless steel S304 thin plates, the tests
were carried out on specimens of ASTM A313M spring steel materials. The results showed that
100 micron thin plate exhibited higher tensile strength with no clear evidence of yielding as
compared to 300 micron plates. The fracture morphology images observed by Scanning Electron
Microscopy (SEM) revealed that both specimens fractured in ductile mode. Formation of dimples
on the fracture surface could be recognized easily in 300 micron sample at higher magnification as
compared to 100 micron sample.

In this study, a design and fabrication of intermittent solar absorption refrigeration unit was
performed at Hillah city in Iraq)32.4o, 44.4o). The absorption solar unit consists of parabolic trough
concentrator (PTC) was used as solar rays mirror reflector with aperture area of 2 m2 , carbon steel
pipe inside a vacuum glass envelop with a diameter of 1.5 in as tubular receiver, condenser, storage
tank, evaporator. The aqua ammonia solution) NH4OH)is used as working fluid with different
concentration (25%, 30%, 35%, 40%). The validity and visibility of the unit were evaluated by
measurements of pressures and temperatures at different parts of the unit during a year from May
month 2014 to July month 2015. The maximum pressure and temperature is found to be 12 bar and
120oC respectively. The coefficient of performance was in the range of 0.01-0.09.

One of the important problems in fine aggregate is the contaminated with interior sulfates in
manufacturing concrete in Iraq. Within standard specifications a difficult to obtain of well-graded
fine aggregate with sulfates content is existed. The present research is devoted to enhancement of
some properties of self-compacting concrete with fine aggregate contains internal sulfates by
partial replacement of gypsum to fine aggregate by weight. This study is bifurcate of selfcompacting
concrete they are: first category is incorporating powder of limestone (LSP) in selfcompacting
concrete and the second one is incorporating 10% rise husk ash (RHA) plus powder of
limestone (LSP). The investigated scales of fine aggregate with sulfates contents were ( 0.37%,
0.5%, 1.0%, and 1.5%) which is corresponding replacement by weight of cement equal of (3.74%,
3.99%, 4.96% and 5.93%) for mixes contained limestone powder and of (3.76%, 4.01%,4.98% and
5.96%) for mixes contains rise husk ash plus powder of limestone. Experimental program of this
study is bifurcate; first one is using superplasticizers and fillers to produce self-compacting
concrete then determine the workability. Second one is to evaluate the mechanical properties such
as splitting tensile strength and compressive strength. It was noticed that, the exemplary content of
gypsum was by weight of cement for all mixes was 0.5%. While increase in compressive strength
in a range between 5.9% and 10.1%, and in tensile strength in a range between 1.2% and 8.5% for
mixes of self-compacting concrete with limestone powder plus rise husk ash instead of limestone
powder.

This study presents an experimental investigations undertaken to evaluate the effect of two
extractant solutions (EDTA- Na2 and/or citric acid) and different conditions (pH, extractant
concentration, and contact time) on the removal efficiency. Iraqi silty soil are studied, the soil was
artificially contaminated with lead (Pb), copper (Cu) and zinc (Zn) to achieve higher levels of
contamination.
A series of batch experiments were conducted to determine the removal efficiency of lead, copper,
and zinc using EDTA- Na2 and/or citric acid. The influence of solution pH, extraction time, and
extractant concentration were studied in order to evaluate the optimum condition for soil washing
process.
The feasibility of soil washing method for decontamination of soil was evaluated in laboratoryscale
batch experiments. Soil samples containing 500 mg/kg of Pb, Cu, or Zn were subjected to
ethelenediaminetetraacitic acid disodium salt (EDTA- Na2) and/or citric acid (CA) treatment. Soil
washing experiments performed on 2.0 g portions of the spiked soil using (0.001, 0.005, 0.01, 0.05,
and 0.1M) chelating agents at a solid:liquid ratio of 1:10 showed that extraction efficiency of
EDTA-Na2 was much higher than that of citric acid, and higher concentrations of complexing agent
lead to better extraction. Results show that EDTA-Na2 was better in releasing soil-bound metals
from the soil compared to citric acid where 67.13% of lead was extracted using 0.1M of EDTA-Na2
while only 36.5% was extracted using the same concentration of CA. Up to 51.48% of copper was
extracted using EDTA-Na2 while only 24.86% was extracted using CA. similar results appear for
zinc, where 44.2% was extracted using EDTA-Na2 and 16.73% was extracted using CA.
The highest extraction values of lead can be observed at pH values from 4 to 5 , copper at pH= 8
and zinc at pH = 9.

One of the fundamental problems in the area of digital speech processing is a speech coding that
has been studied for years. Speech coding simply transforms the speech signals as fewer numbers
of binary digits as possible, which can be then transmitted through channels or stored in memory
devices. Due to the fact that the bandwidth of the channels is not unlimited, speech compression is
needed to let more space bandwidth; thereby more speech coded signals can be sent over same
channel bandwidth. Linear Predictive Coding (LPC) that is based on linear prediction (LP) model,
which is a method to represent and analyze human speech, is one of the most common speech
coding techniques. It is used in compression the digital speech signals, resulting low bit rate. This
method has become the dominant technique for determine the fundamental speech parameters such
as pitch, formants, spectra, vocal tract area functions. However, the weakness of LPC is in
estimating the fundamental speech parameters causes poor voice quality and performance. The aim
of this paper is to build a system with precise detection of speech parameters for encoding a better
speech quality at low bit rate. This can be done through proposing a modified version to the voiceexcited
LPC vocoder based on Discrete Cosine Transform (DCT) and quantization of residual error
while retaining low bit rate; hence conserve the bandwidth. Segmental power signal to noise ratio
(SEGPSNR) and mean square error (MSE) as an objective measure for speech signal quality are
implemented for the proposed improvement through computer simulation using Matlab 11.

Solidification and microstructure are important indexes to evaluate the mechanical properties
and qualities of casting. Directional solidification describes solidification that occurs from the
farthest end of the casting. This study is devoted to show the directional solidification effect of
copper-aluminum alloy (95%Al,5%Cu) on hardness and microstructure.. This was achieved by
varying the temperature of water flowing from the base in three different temperatures (0,10,20 )ºC
by using a chilling base. It was concluded that the difference in the solidification of the three
samples was due to the different cooling rates applied and as a result of low temperature of
sample, which the chilling base temperature was (0ºC) compared with the rest of the samples
which led to soften the dendrites crystals, and highest hardness reading obtained due to low
temperature of the cooling base of sample.