Al-Qadisiyah Journal for Engineering Sciences

Controlling of the pH system theoretically was achieved successfully using vibrational control
method with very small offset. Modeling of pH system was derived using reaction invariants
concept where the specific invariants combined and adapted in the mole balance equations with
contribution the charge balance to give the final pH process model.

This paper presents a study the performance and to improve energy efficiency of the
traditional pneumatic driver, three supply pressures used 4, 6 and 8 bar, by cutoff flow
process occurs at stroke end of the actuator before execution position, in which pressure
supply line cutoff and the exhaust line remains open in position specified previously. The
piston stroke completes rest under the influence of air expansion , the inertia force of the
piston exactly at execution position, that is saving in compressed air and energy, reduced
in required air additional to reduce the cost. compared with the traditional control of
motion of the asymmetric cylinder in which maximum energy saving obtained at 6 bar
are 16.7%.

One of environmental pollution and global warming sources is cement industrials. In line to
diminish the effects of cement industrial activities on environment, wastes are used in cement
mortar as a partial replacement of cement weight throughout the present study. These wastes
comprise poultry egg shell which is wealthy in calcium and glass of bottles of juices and soft drink
which has high content of silica. Both types of wastes were grinded carefully and passed sieve No.
200 ( 75µm opening size) to produce egg shell powder (ESP) and milled glass (MG). Cement was
substituted by (5%, 7.5%, and 10% ESP), and (10% MG). These ratios of replacement was
evaluated individually and in groups by compressive strength test at age of 28 days and drying
shrinkage test at ages of 4, 11, 18, 25, and 60 days of drying. Results of tests indicated that
compressive strength and drying shrinkage have the same trend when the replacement ratios of ESP
used individually in mortar mixes. The higher results were recorded with ratios of 5% and 7.5%.
While, compressive strength increased when 10% of MG was used as a partial replacement of
cement, and drying shrinkage decreased at ages 11, 18, and 25 days of drying. The combination of
MG and ESP in one mix, decrease compressive strength in all percent of addition. However the
gathering of MG to 5% of ESP, and MG to 7.5% of ESP decrease drying shrinkage at all age of
testing when compared it with the reference mix.

In this paper, an experimental and numerical study of dynamic deflection and dynamic bending stress
of beam structure under moving load has been carried out. The moving load is constant in magnitude
and travels at a uniform speed. The dynamic analysis of beam-type structure is done by taking three
(39.24, 58.86 and 78.48) N concentrated loads; each one of them travels at two uniform speeds(0.2
and 0.25) m/s . The theoretical analysis is based On Euler- Bernoulli theory and Fourier series
solution. A finite element model of a beam vibrating under moving load is established by ANSYS
software. The comparison between the numerical dynamic stresses of beam via ANSYS software with
the experimental results showed that the percentage error of (15%). Effect of the speed and load
variables on the dynamic stress and dynamic deflection is investigated. It is concluded that the
influence of variable speed on the dynamic deflection and dynamic bending stress is more than the
effect of variable load on them. On the other hand, the dynamic bending stress is more sensitive to the
variable speed and load than the dynamic deflection. Dynamic bending stress and dynamic deflection
due to moving load could become significantly higher than those obtained with the stationary loads,
thus they must be considered

The increased demand for renewable energy calls for increased developments to the
techniques of production for such energy. This paper presents a numerical study of conical
collector solar chimney with specific dimensions. A glass spiral of square cross section was
fitted to the collector to investigate its effects on the velocity distribution of air. Results show
that the spiral enhances velocity distribution by (11.57% and 12.82%) corresponding to the
inlet air velocity of (Re=99945 and 499729) respectively. This enhancement will reflect to
the instantaneous electric power which can be produced by such instrument. The
investigation was carried out using CFD program FlUENT14.5, K-ɛ model.

A thin film of titania (TiO2) was deposited onto AISI 316L steel using physical vapour deposition
(PVD). Coating thickness was measured using Elecometer instrument and it was
(150µm).Corrosion resistance to (H2SO4,HCl, H3PO4, and HF) acids with (2&4) pH, and to (NaOH,
KOH,Ca(OH)2, and NH4OH) basis with (10,12) pH, of coated specimen was measured at
temperatures ranges from (25-190) Co
by weight loss method. It has been found that TiO2 coating
largely enhance corrosion resistance of steel alloy especially at high temperatures.

In this work, a hybrid fiber reinforced composite rod fixed from one end, while the other end is left
free and subjected to a static torsional load, and left to vibrate freely after load releasing. Fiber
volume fraction of 40% is considered to rod of interest, the matrix is composed of 20% short fibers
and 40% pure matrix (this type of matrix is called composite matrix, which is well known and
widely used in fiber reinforced hybrid composites). Such a ratio is adopted since it gives enough
strength and reinforcement and meet the economic requirements as well, as mentioned in
Mechanics of Composite Materials by Jones 1999. Four various long and short fibers of the same
type and four matrices are taken to construct the rod in order to introduce the different properties to
investigate their effects on natural frequency under torsional excitation. The problem is manipulated
using software of AnsysV.14. The elastic properties of materials are determined using software of
Matlab v.7. The results show that natural frequency is mainly highly affected by matrix longitudinal
elastic modulus than that of fibers, and displays a regular pattern of behavior. The fibers show an
irregular behavior towards the natural frequency variation. This can be attributed to the interaction
effects between three types of constituents, matrix, long and short fibers composing the whole
structure of the rod. In addition, there is the effect of anisotropy of material effective elastic
properties, which plays an important role in results irregularities.

The type of materials such as subgrade, subbase and base has a great effect on the quality and life of
pavement. The nature of subgrade soil has the most important effect among other materials. There
is a real concern in construction flexible pavements over a weak subgrade and the California
bearing ratio (CBR) is very low for such soils. Therefore, the constructed pavements for such cases
require more thickness. In fact, there is a need to look for economic methods in order to replace the
lack of suitable construction materials for pavements such as subbase and base materials. This work
studies the effect of geogrid reinforcement on CBR of subgrade soil and total pavement thickness.
The soft sand soil from Al-Najaf city and one type of geogrid have been selected. It has been found
that there is a significant improvement in CBR of subgrade resulting from geogrid reinforcement.
The results indicated that the value of CBR was about 2.14% without using geogrid whereas this
value was 12.84% in case of putting geogrid at 0.2H from the top of the specimen. Also, the
reinforcement of subgrade with geogrid at 0.2 from the subgrade layer thickness will reduce the
total pavement thickness by (30-40) %. Then, the same case study has been modeled using Plaxis
(3D) software which is a finite element package. This package is equipped with specific features to
deal with different complex cases and structures to simulate a realistic of case under study. The
encouraging results have been obtained.

This paper presents an analytical calculation and experimental investigation to evaluate the American and
British methods usually used for mix design of normal concrete. Six concrete mixes with different target
of mean strength were design using crushed and uncrushed aggregates. A reliable approach has been
suggested to calculate the mix proportions. In order to validate the former approach, an experimental
programme was running to measure the workability aspect and compressive strength of three selected
concrete mixes designed for strength levels of 21.5 MPa, 27.5 MPa and 36.5 MPa at different sample ages
using 108 cubes.
The results obtained showed notable differences between the approaches of American and British
methods adopted to calculate the mix proportions. There was no indication have found in the American
method to distinct between design the concrete mix containing crushed aggregate and that of uncrushed
aggregate. The procedure followed in British method produced concrete mix with higher strength than
that designed according to American method. The experimental results of compressive strength and
workability showed close agreement with the suggested approach for calculation the mix proportions.