Journal of Engineering

Foamed concrete (FC) is a lightweight concrete that can be designed to meet specific
strength or density criteria. Foamed concrete with an efficient design, guarantees the
desired qualities of durability and strength to be attained. This study aims to predict the
compressive strength of foamed concrete produced with rice hush ash as cement partial
replacement at 5-30%, using the strength-porosity prediction model with a density of 1600
kg/m3. In order to create the model, a relationship between strength and porosity
characteristics was used. The fundamental constant was also found using the numerical
analysis bisection method. The characteristics of the fundamental component materials and
density that influence the hardened state are examined in this study to investigate the
characteristics of foamed concrete. Based on the validity of the results, it can be deduced that
the model is appropriate for a laboratory-tested sample of foamed concrete made using rice
husk ash as partial cement replacement. Strength-porosity model correlates well with the
laboratory-measured strength as it employs the composition of constituents. It is however
clear that a strength prediction model can be produced through a selection of criteria such
as density, material characteristic properties and proportions to suit different purposes of
use and application.

Concrete-filled steel tubes (CFST) are structural members consisting of hollow steel tubes
filled with concrete. Both steel and concrete work together to provide several advantages.
The concrete increases the steel tube's resistance against local buckling while the steel tube
confines the concrete, which increases its compressive strength. The use of CFST beams
increased in high buildings due to their great mechanical properties. The researchers were
interested in CFST beams because of their great ductility, stiffness, strength, and flexural
capacity when compared to hollow steel beams. The properties of CFST beams were
enhanced in several ways, for example, by using carbon fiber reinforced polymer (CFRP)
wrapping, adding an external steel plate, and using recycled aggregate. In addition, the
concrete properties were improved by adding steel and synthetic fibers. This review paper
covers research conducted on CFST beams since 2019. It gives an overview of what was
studied and explored and what still needs more research.

This paper presents a multi-input multi-output (MIMO) high-coupled nonlinear model of a
twin-rotor aerodynamic system (TRAS). An optimal sliding mode controller (SMC) is
proposed to control the TRAS system. Two optimization algorithms, namely Grey Wolf
Optimization (GWO) and Whale Optimization Algorithm (WOA), are used to tune the SMC’s
parameters. Which are effectively implemented in this controller. The simulation results are
given to demonstrate its effectiveness. To evaluate the performance of the proposed
controller, a comparison with a previous study—that used Genetic Algorithm (GA), Particle
Swarm Optimization (PSO), and Simulated Annealing (SA) algorithms—has been conducted.
The results of the proposed controller reveal better performance indices than the previous
study. In addition, a novel performance index is presented in this paper as an objective
function for designing SMC parameters. Which is identified by the Integral of Quadric Time
multiplied by Absolute Error (IQTAE). To verify the effectiveness of the proposed IQTAE, a
comparison was conducted with the previous study that used traditional performance
indices (ISE, IAE, ITSE, ITAE). To guarantee a fair comparison, apply the same optimization
algorithms (GA), (PSO), and (SA) that were utilized in the previous study. By using this
method, it was possible to compare the performance indices under the same conditions. The
simulation results show the superiority of the novel performance index, especially in
reducing overshoot. The percentage enhancements of the overshoot of both azimuth and
pitch angles reach, respectively, 58.7% and 99.35% with GA, -0.65% and 70.1% with PSO,
and 44.53% and 88.59% with SA.

High population density, land exploitation, and water scarcity are the biggest problems in
the world. To solve these problems, floating solar power plants were chosen because of the
advantages of this system and high efficiency compared to land systems. In this study, the
reservoirs of the five main dams in Iraq were chosen: Dukan, Darbandikhan, Hamrin,
Haditha, and Mosul. They were covered with percentages of 5%, 10%, 25%, 50%, 75% and
100%. This study aimed to produce energy and meet the population's electricity needs and
evaporation losses. The results revealed that covering the reservoirs by 100% can produce
230.53, 7526666, 15561, 244059, and 184692 MW from reservoirs of Dukan, Darbandikhan,
Hemrin, Haditha, and Mosul dams respectively. Evaporation results show that covering
dams by 100% can produce 14.12, 471.40, 16.34, 27.03, and 20.08 million cubic meters,
the result revealed that covering the dam's reservoirs by 75% could reduce the evaporation
rate by 15 times.

A new model equation has been constructed to estimate the liquid limit value, using the
rapid one point method. Data processing was carried out in Microsoft Excel and SPSS,
visualizing and using 6,210 theoretical trial points, which resulted from 135 samples along
the actual flow index line, with the number of blows varying from 5 to 50 with an interval of
unity. The model has two correction factors (CF), both of which are functions of the number
of blows at the trial point in the test. The first CF is applied to the trial moisture content,
while the second CF is applied to the previously estimated liquid limit. This technique was
checked against real data points. For estimating the liquid limit for a large range of blows
(N) from 10 to 45 the model achieved a high R2 value of over 0.99. It also has a low RMSE of
3.8 for the set of 6,210 theoretical points and 2.2 for 220 actual points. In this research, the
flexibility of the model is crucial as it provides a wider range of blows from 10 to 45, unlike
the ASTM procedure for which there are set requirements that state the amount of blows to
be between 20 and 30

This study's primary emphasis was locating appropriate locations in the valley of Al-Abyadh
for water harvesting dams. Water harvesting techniques are one possible answer for Iraq's
water difficulties caused by climate change and the existing dams in the high reaches of
rivers, which have exposed the world to severe drought. Water harvesting is collecting water
from a specific area, beginning with rainwater in the ground and conserving it by building
dams to store it. Valley Al-Abyadh, which extends 268 km and has an area of 4188.96 km2, is
situated in Anbar Governorate's western desert. Water flows into the Al-Abyadh valley
through four basins. This study aims to examine the four basins hydrologically and analyze
the data using the HEC-HMS software to find the best places to put water harvesting dams
and how much water they can hold. ArcGIS 10.8 and HEC_HMS 4.11 were used for the
analysis of the maps. 2008–2022, We used real rainfall data from the meteorological and
seismic monitoring division. The simulations determined a storage capacity of 1045.69056
M ????3 run using actual rainfall data inside Valley Al-Abyadh. Work on rainwater harvesting
dams began in the basins of the valley Al-Abyadh. Every basin has reached its maximum
storage capacity, respectively14,11,20,10 (46.27584M ????3, 42.81984M ????3, 63.19296M ????3,
65.00736 M ????3). The study shows that water from these dams might be used since Valley
Al-Abyadh has the highest storage capacity among water harvesting dams and the lowest
loss rate.

In several developing countries, the increasing request for housing and budgetary
constraints have directed governments to search new ways of housing delivery. Many
governments adopted an option partnership with the private sector commonly referred to
as Public Private Partnership (PPP). The purpose of this study was to investigate the most
important legal and political, government support Factors affecting the Implementation of
PPPs in residential investment ventures in Iraq thereby reducing the housing deficit in the
country.
An
inclusive
research
technique
comprising
a
written
review,
interviews/discussions with decision-makers, professional experts, and seasoned
practitioners, as well as a questionnaire, was used to extract the data for this study. One
hundred questionnaire models were sent to public institutions, private sector companies,
and government agencies. The responses were then subjected to statistical analysis. The
outcomes show that the most five important legal and political factors were
inefficiency/efficient legal framework with (Relative Important Index) RII=0.79;
unstable/Stable political system with RII=0.79; corruption with RII=0.78; the growing
phenomenon of partisanship with RII = 0.78; Commitments of the public and private sector
with RII=0.77. While that the most five important government support Factors were Land
acquisition with RII=0.77; Grants with other forms of financial support loans with RII=0.76;
Government's supportive stance on investments from the private sector with RII=0.75;
Project Ownership Issues with RII=0.73; Relief in certain Force Majeure events with
RII=0.72 this factors can be taken in consideration for making any investment decision.

Since the coverage of millimeter waves (mmWave) is limited due to high path loss and
blockage, it is deployed in small cells. This dense deployment of base stations and access
points resulted in significant interference. Therefore, interference mitigation is the main
challenge in designing the new millimeter-wave communication technologies in the existing
5G system. Therefore, in this paper, a two-tier Heterogeneous Cloud Radio Access Network
model is presented, which performs a technique inspired by soft frequency reuse (SFR) to
mitigate interference. The cellular service region is divided into two sub-regions, center
region is served by conventional macro base stations, which operate in the sub-6 GHz
frequency band, while the edge area is served by Remote Radio Heads (RRHs), which operate
in the millimeter-wave frequency band to avoid interference between tiers. User-RRH
associations are introduced to mitigate interference between small RRHs and maximize
network throughput using an Online Multi-Agent Q-Learning (MAQL). The proposed MAQL
solution, based on the least path loss as a basic criterion for User-RRH association,
outperforms in average network throughput per user a previous study based on average
SINR as a basic criterion for association for two types of RRHs deployment scenarios in the
heterogeneous network approximately by 66.4% and 21%, respectively, at the lowest
number of users. The difference gradually decreases with the increasing user numbers until
it reaches 8.7% and 9.8%, respectively. Even though the gap between throughput
performance narrows as user density increases, the proposed method consistently
outperforms the alternative strategy, indicating its ability to adapt and manage network
resources more effectively even under higher traffic loads.

Moisture damage is the most commonly occurring problem, causing layers of asphalt
pavements to break apart, reducing the serviceability of roads. The utilization of recycled
polymer in asphalt mixtures has become popular because it may offer environmental
benefits. The present study aims to investigate how the use of recycled polypropylene (RPP)
can reduce the moisture susceptibility of hot mix asphalt (HMA). Asphalt binders were
modified with three different concentrations of recycled polypropylene: 1%, 3%, and 5% by
weight of the bitumen. The Marshall mix design method was utilized to establish the optimal
asphalt content for the specific aggregate gradation both the control and modified mixtures
were tested for moisture damage. Tensile and compressive strength tests were conducted
to assess the moisture damage in asphalt mixtures. In the results, an optimal amount of RPP
was found in asphalt mixtures, which improved Marshall properties. The same goes for their
resistance to any moisture damage, which was also able to be considerably improved with
this addition. The maximum tensile strength ratio (TSR) was 86.45% at 3% RPP, and the
index of retained strength (IRS) of up to 81.99% by addition of 5% RPP, while the control
mixture exhibited 80.25% for TSR and 75.82% for IRS. These results have shown the
viability of applications with RPP in asphalt mixtures towards improved pavement
performance and sustainability.

The application of two-wheeled self-balancing robots to real-world tasks critically depends
on their ability to actively reject disturbances. The objective is to design two active
disturbance rejection controllers (ADRCs) for body angle and displacement, respectively, for
a two-wheeled self-balancing robot system, which is difficult to control due to strong
coupling, nonlinearity, and parameter uncertainty. Based on the system dynamics, an ADRC
control framework is designed to estimate and compensate for modeling errors and
disturbances online. Numerical simulations are used to demonstrate the effectiveness of
ADRC in different controller combinations, using Simulink MATLAB 2022a and tuning
parameters by genetic algorithm (GA) to ensure good temporal performance and assist in
the design parameter selection process. Studies on a real two-wheeled self-balancing vehicle
show that the constructed ADRC scheme allows the vehicle to operate more than 90% more
stably and effectively than the assumed control strategy, which can effectively realize the
self-balancing and steering process with the performance of fast adjustment speed, high
accuracy, and strong robustness as well when compared with the PID (proportional
integral-derivative) controller under the same parameter setting.

The research focuses on examining the level of harmony in the formal characteristics among
the elements of the traditional Baghdad alley, from individual components to the entire area.
Numerous studies have highlighted the unity and cohesion in the urban structures of
traditional Arab urban environments, including Baghdad alleys, despite the diversity of the
urban landscape. The study's theoretical aspect focuses on the visual features of the
traditional urban environment, emphasizing the concept of diversity within unity. This is
explored through specialized studies in the field. The applied part of the study involves using
fractal geometry tools, specifically the box-counting method, to measure the degree of
harmony and variation within different parts of the urban environment. This assessment
starts from individual parts and expands to the panorama on both sides of the alley. This
research aims to highlight the visual characteristics of traditional alleys that are essential to
their urban framework. It is imperative to incorporate these characteristics into new urban
plans to effectively uphold the local identity. The research problem is the lack of studies on
fractal geometry as an analytical tool for designers to achieve specific formal characteristics,
such as harmony between parts and the whole, particularly in the context of traditional
paths. The research took into account the historical, social, and cultural influences on urban
design in Al-Mutanabbi Street. The findings revealed that these influences significantly
shape the urban framework and enhance the cohesion among different elements.

Plastic waste materials are constantly increasing around the world as a result of the growing
human consumption of these materials day by day, with no actual solutions to get rid of them
without causing harm to the environment or the health of living organisms. Therefore, in
this research, two types of plastic waste materials are utilized to enhance soft clay soil:
polyethylene terephthalate (PET) and nylon (N), in percentages of (1, 1.5, 2, 2.5)% from dry
soil weight, to enhance the clay soft soils properties, which are characterized by their
excessive compressibility, low bearing capacity, and low shear strength. This study is carried
out by conducting laboratory tests before and after the addition. These tests included the
unconfined compressive strength (UCS) test, and the other test was the consolidation test.
The results revealed a notable rise in the cohesion value (C) when using polyethylene
terephthalate (PET), when the enhancement reached 246.42% with 2.5%, while the
maximum improvement percent with nylon was 25% with 1.5%. On the other hand, when
applied at a rate of 2%, nylon trash was more effective than plastic water bottles (PET) in
reducing the compression index (Cc), dropping from 0.26 to 0.15.