Journal of Engineering

Despite the depleting fossil fuel reserves and growing environmental concerns, the world’s
energy consumption is still rising, resulting in the development of unconventional and
alternative energy sources. A byproduct from the distillation of crude oil, residual fuel oil
(RFO), also known as bunker fuel, finds extensive application in power generation and
marine transportation. Because of its high viscosity, high Sulphur content and incomplete
combustion, RFO has not gotten much attention in recent fuel research, despite its high
energy content and widespread availability. This study examines RFO's physicochemical and
thermal properties in contrast with standard fuels such as diesel, biodiesel and high-sulfur
fuel oil. In determining RFO's suitability for combustion applications, a comprehensive
laboratory investigation was performed, including viscosity, density, calorific value, cetane
number, Sulphur content, and auto-ignition temperature tests. Thermal degradation
patterns, combustion temperature ranges, and emission properties were also investigated.
The results conclude that RFO needs to be pretreated before use, with options like heating
or blending. The calorific value of RFO is found to be close to diesel, making it a potential
substitute for an alternative fuel, a viable and cheaper option, for stationery and large-scale
engines. There are still certain issues related to its use, such as ignition delays, particulate
emissions and regulatory compliance. The study suggests that RFO has the potential to be
used as fuel, when suitably modified, in areas where getting access to refined fuel is difficult.
Future work on the study includes fuel upgrades, engine system modifications & long-term
combustion and emission studies to improve its usability and acceptability

For fast data rates, commercial 5G wireless communication systems are in use. However, for 5G, the
challenge lies in the expansive use of smart devices and the need for ultra-reliable and low-latency
communication in Internet of Everything (IoE) services. The data rates achieved in 5G are too low
for this exponential increase in traffic and, as such, there is the need for 6G network technologies that
can enable this. Cloud Radio Access Network (Cloud-RAN) is one such network that has been
proposed for B5G services. In this work, it is proposed to develop and test a C-RAN on the OMNET++
simulator. In this network setup, the BBUs are separated from the RRHs, and the baseband
processing tasks are completed in the cloud for cost-effectiveness. Simulations were done on Simu5G
for the RRH and user part, and iCanCloud for cloud-based BBUs. Results demonstrate that
considerable improvements of up to 30% in energy consumption, 45% in the efficiency of use of
resources, and low latency of less than 10ms, as well as stable throughput performance for different
user loads, were achieved. Results validate that the implementation of C-RAN can improve efficiency
and scalability. The conclusion drawn from this study is that the proposed C-RAN architecture is a
viable and impactful solution to meet the growing demands of future wireless networks.

The present work evaluates the effects of different solar radiation values (350, 400, 650,
900, and 1000 W/m²) and module temperature on the monocrystalline solar module output
current, voltage, and power. A five-parameter model was chosen to design a simulation
program to study and analyze the effects of irradiance and temperature on the output power
of a solar module. Solar modules are defined by electrical factors like open circuit voltage,
short circuit current, maximum power, maximum current, and maximum voltage, that not
supplied by the manufacturer. The proposed work is suggested for the accurate
determination model of a mono-crystalline solar module. Ideality factor calculation is by
using the mathematical function, Lambert W function and series, and shunt resistances lead
to extracting solar module parameters. The fitness of the five-factor formula is related to the
lower RMSE average values. The average root mean square error of measured current
voltage values with the corresponding calculated values by the five-parameter model was
calculated (0.0667). The lowest value of the root mean square errors of measured voltage
current characteristic values with the calculated ones is 0.022 at irradiance of 1000 W/m2
and module operation temperature of 25 °C. Certainly will enhance the present work's
fitness, represented by measured data or calculated model data with RMSE equal to 0.0667.
It noted that the present work is so close to other important previous work, and that
certainly enhances our work fitness (represented by measured data or calculated model
data) with a 0.46 percentage of power drop per degree centigrade.

This study aims to improve mild steel's corrosion resistance in marine applications. Mild
steel has low corrosion resistance, especially in salty conditions, so enhancing this property
is required. This study aims to increase the corrosion resistance of mild steel by heat
treatment processes. The specimens were heated to the temperature of 800°C, then the
specimens were separated into two groups, specimens of both of the groups cooled inside a
furnace (annealing), cooled in air to room temperature (normalizing), and cooled in water
(quenching), then the first group of specimens was immersed in salinity of (33.9) ppt for 45
days, and the other group of specimens was immersed in salinity of (37.8) ppt for 45 days.
The corrosion resistance is determined experimentally by the weight loss method, with the
consideration of the effect of each parameter, such as salinity and cooling rate. The results
obtained showed that corrosion resistance in the quenching process is higher than in other
cooling processes in both salinities, followed by annealing and normalizing processes. In
which the weight loss of the quenched specimen was (0.0057) g in a salinity of (33.9) ppt,
while it was (0.0072) g in (37.8) ppt.

One of the most urgent issues confronting cities in the south of the globe is urban expansion
brought on by population increase. Iraq's capital, Baghdad, is a striking example of this
change. This study examines how Baghdad's agricultural land was converted into residential
areas between 2003 and 2024, with a special emphasis on the neighborhoods of Dura, Al
Buaitha, and Krayat. During this period, Baghdad's population grew from 5.6 million to
nearly 9.1 million, and the city's land usage drastically changed. Due to housing needs and
infrastructure development, population increase has a direct impact on land consumption,
as seen by this geographical expansion. The study illustrates the adverse correlation
between urbanization and the accessibility of green and agricultural spaces using previous
land use data, demographic estimates, and environmental indicators. The main focus is on
the socio-spatial effects of losing agricultural land, the growth of informal housing, and
deteriorating environmental quality, even though temperature rise and CO2 emissions are
mentioned. Through trend analysis, maps, and charts, the research emphasizes how urgent
it is to combine land preservation tactics with sustainable urban development.
Decentralizing expansion to satellite towns, encouraging vertical construction, and
enforcing zoning laws are some of the main ideas. The results show that Urban areas grew
from 387.0 km² to 641.7 km², while green areas decreased from 283.5 km² to barely 81.9
km². As a result, if proactive planning isn't done, the city's long-term resilience and livability
may be threatened by permanent land degradation brought on by population growth.

Integrating sustainability in construction project management requires practical,
management-oriented approaches addressing environmental, economic and operational
challenges. This study is a review and prioritization of management and process strategies
involved in integrating the concept of sustainability into construction projects. The research
methodology included a systematic literature review, followed by expert validation with an
open-ended questionnaire, and a closed-ended questionnaire that was distributed among 83
professionals. The information obtained was examined by applying the Kano model and
Timko indices to rank and prioritize strategies according to their impact on stakeholder
satisfaction and dissatisfaction. The results show that strategies which are resource
efficiency, construction waste reduction, environmental compliance and site safety
management were found to be high impact Attractive attributes with good potential to
improve feelings for stakeholders. In addition, three strategies that were originally
considered Indifferent in the Kano model were identified as Attractive using Timko analysis
which shows their increased importance in operational sustainability practices. This study
presents an empirically-based prioritization framework that provides good information for
construction decision-makers to give guidance on the most influential strategies for
sustainable project delivery.

This paper investigates the thermal buckling of laminated composite plates based on a
refined plate theory that incorporates four variables, using hyperbolic and polynomial shear
strain functions for the first time to analyze thermal buckling of a laminated plate with all
edges simply supported. The proposed shear function incorporates the variation of
transverse shear stress over the thickness of the plate in a parabolic form and achieves zero
traction on the upper and bottom surfaces of the plate without implementing a shear
correction factor. Equations of motion are derived according to the principle of virtual
displacement. The analytical solution is carried out using Navier’s solution. The numerical
results of the orthotropic properties of both cross-ply and angle-ply laminates are calculated
by programming a MATLAB code. In the present study, the influence of changing various
design parameters, such as aspect ratio (a/b), orthotropic ratio (E1/E2), thickness ratio
(a/h), and thermal expansion coefficient ratio (α2/ α1), for symmetric and antisymmetric
laminated composite plates is analyzed. The results are evaluated by the assumption of
uniform temperature variation through the plate, which exhibits good agreement for both
thick and thin plates compared with previous studies.

High-rise structures are a significant indication in contemporary urban improvement,
mainly in areas characterized by accelerated urban growth and dense population. This type
of building should be designed to withstand severe load conditions. Therefore, using
composite structural elements in such structures is required for stronger and durable
elements. This paper introduces a finite element analysis model for Concrete Filled Stainless
Steel Tubular Columns (CFSST) of (100x100) mm cross-section and (1250) mm length to
inspect the impact of concrete compressive strength on the response of (CFSST). The
generated model was first evaluated through a comprehensive comparison with
experimental research. Then, after the model was used to study the considered parameter,
namely, concrete compressive strength. A wide range of concrete compressive strengths was
included (45, 50, 55, 60, 65, 70, and 75) MPa. FE results indicated that the CFSST columns'
ultimate strength is directly proportional to the fill-concrete compressive strength. The
optimum gained load capacity was (416 kN) when the concrete strength was 75MPa. The
modification of increasing fill-concrete compressive strength extended to include the
stiffness, toughness, and the yield load to be (89, 38.9, and 64%), respectively, as the
strength increased to 75MPa. The response improvement didn’t include the ductility index.
A reduction in the ductility index was observed as the filled-concrete compressive strength
increased, reaching 15.4% when the compressive strength reached 65 MPa. This reduction
remains constant, even though the compressive strength increases (from 70 to 75 MPa)

This study presents the design and fabrication of a single-mode optical fiber-based sensor
capable of identifying different concentration levels of acetic acid solutions. Carbon quantum
dots were deposited onto the core region of the optical fiber following chemical etching of
the cladding layer using hydrofluoric acid (HF). The sensor was evaluated using five acetic
acid concentrations (10, 15, 18, 20, and 25%) to determine its sensitivity based on variations
in resonance wavelength and optical transmission. When exposed to larger concentrations,
the sensor clearly showed a red shift in resonance wavelength, indicating a direct correlation
between the optical response of the sensor and the refractive index of the detecting medium.
Since traditional methods frequently have low sensitivity and large instrumentation. There
is an increasing demand for a small and extremely sensitive approach to detect acetic acid.
Spectral and intensity analyses confirmed the sensor's performance, showing a sensitivity
measurement of 10 µm/RIU and an established ratio of signal-to-noise of 0.14. Surface
Plasmon Resonance (SPR) is the main basis for the sensing mechanism enabled by the
relationship between the fiber's evanescent field and the carbon quantum dot coating. The
testing results establish that the sensor performs efficiently in detecting liquid chemicals,
especially acetic acid and related organic substances. A specially fabricated tapering setup
was employed to enhance the sensor’s responsiveness to changes in the surrounding
refractive index. A short-tapered segment of single-mode fiber, approximately 4 cm in
length, was formed at the center of the sensor. The tapered region, with carefully controlled
cladding diameter and length, was exposed to acetic acid solutions with different
concentrations in order to monitor variations in the effective refractive index (RI).

This study develops prediction models for smart management system of construction
projects by identifying the parameters that influence project cost and duration. Among
sixteen parameters, the Fuzzy DEMATEL model is applied to a sample of ten construction
projects to estimate the net influence weights (D-R) of these parameters on cost and
duration of these projects. The outcomes indicated that the model demonstrated high
accuracy in predicting the key parameters affecting cost and duration. In particular, both the
"application of sustainability standards" and "effective coordination between contractors"
significantly impact project cost and duration. On the other hand, "the availability of raw
materials" was found to be a parameter with lower influence. Based on these outcomes, the
model offers a visualization of causal relationships, which supports in prioritizing smart
project efficiency. This study highlights the importance of fuzzy-based methodologies in
construction project analysis and offers a practical framework for decision-making to
enhance planning and implementation in smart construction projects.

Scheduling problems are central to operations research because of their direct impact on
productivity, resource utilization, and system responsiveness. This study addresses a novel
tri-criteria and tri-objective model that provides an innovative framework for analyzing
complex single-machine scheduling problems of minimizing total completion time (∑????????),
total earliness (∑????????), and maximum lateness (????????????????), as well as their aggregated form. The
problem remains computationally challenging for large job sizes (up to n = 8000). To
evaluate solution performance, three independent approaches were employed: the Branch
and Bound (BAB) algorithm and two local search methods, Tabu Search and the Bees
Algorithm. While BAB provides precise answers for small cases (n ≤ 19) with low AAE, its
computational time increases significantly with problem size. Tabu Search balances solution
quality and computational effort to produce near-optimal solutions with modest execution
times for medium and large-scale examples (n = 500–8000). While the Bees Algorithm may
not match the precision of exact approaches, it offers faster computation and produces a
variety of solution patterns. These features make it especially appropriate for large-scale
problems or situations with restricted computational time. Moreover, this study offers
practical insights to support the selection of suitable solution techniques, taking into account
problem size, available computational resources, and the required balance between
efficiency and solution quality.

Drying shrinkage can lead to microcracking and reduced durability, especially when
external curing is insufficient. Internal curing effectively addresses this issue by supplying
additional internal water that sustains hydration when external curing is inadequate, water
to the concrete matrix to sustain hydration, and alleviating strains caused by shrinking. This
study investigates the influence of internal curing utilizing water-absorbing polymer balls
(WAPB), lightweight aggregate (LWA), and their hybrid complex on the drying shrinkage
and flexural strength of concrete. Seven concrete admixtures were developed: two
references (Rw, Rair), WAPB, 50% LWA, Hybrid (25% LWA + 5% WAPB) following ACI
211.1, and two fully lightweight concretes (LWAw, LWAair) following ACI 211.2. Flexural
strength was tested on 100×100×400 mm prisms (9 per mix) at 28, 60, and 90 days
according to ASTM C293. Drying shrinkage was monitored on prisms of the same size per
ASTM C157 with a 200 mm gauge length. The results showed that the 50% LWA mixture
achieved the greatest reduction in drying shrinkage (67.5×10⁻⁶ at 28 days; 175×10⁻⁶ at 120
days), decreasing strains by approximately 61% at 28 days and 42% at 120 days compared
with the reference mix. The Hybrid mix also demonstrated stable long-term behavior with a
14% increase only between 28 and 120 days. The flexural strength slightly decreased in all
internally cured combinations relative to the water-cured reference because of increased
porosity; however, it remained within acceptable structural limits.