Journal of Engineering

Rectangular gravity separators are commonly used within wastewater treatment systems
to remove fat, oil, and grease from water. The performance of these vessels is dependent to
a great extent on the uniformity of the flow, since turbulence and recirculating eddies tend
to break drops together, thus reducing the separation efficiency. Therefore, adding the inlet
baffle is a feasible way to improve the hydraulic stability in the separator. To simulate the
characteristics of flow in the gravity separator tanks, a two-dimensional computational fluid
dynamics (CFD) model of a single-phase flow has been developed with Flow-3D (v11.04).
The numerical model employed was based on the Finite Volume Method (FVM), used the
Volume of Fluid (VOF) technique to simulate the free surface behavior, and implemented an
RNG k–ε turbulence model. Flow behavior was analyzed using three parameters: the velocity
standard deviation, which denotes the flow uniformity, the percentage of recirculation zones
corresponding to mixing and stability, and kinetic energy distribution. The results showed
that the baffle with two apertures provided the best hydraulic performance by minimizing
velocity fluctuations and cross-flowing and also kinetic energy distribution. Thus, this
arrangement was determined to be the most effective design in promoting the flow stability
and separation performance inside a rectangular gravity separator.

The accuracy in oil reserve estimation is very important, as decisions should be made based
on this value. The present paper will deal with estimating oil reserves by using deterministic
and probabilistic approaches. The case study is the Mishrif formation of the Buzrgan oil field
that located in Missan Governorate, southern Iraq. The deterministic approach is
represented by the material balance equation, while the probabilistic approach is
represented by Monte Carlo simulation. The data used in the material balance equation are
production, PVT, and pressure data, along with needing to calculate bulk volume and
porosity, while the Monte Carlo simulation needs volumetric equation parameters, which
are porosity, fluid saturation, net pay thickness, and reservoir bulk volume. The linearized
material balance equation, the Havlena – Odah method, is used. Monte Carlo simulation is
applied as a volumetric equation, but each input parameter is modeled to get the best value.
The result of the oil reserve by the material balance equation was 4.368 billion stock tank
barrel while by Monte Carlo simulation was classified by Hefner and Thompson’s
classification as P90 proven reserves is 1.03279 billion stock tank barrel, proved and
probable oil reserves P50 is 1.98761 billion stock tank barrel, and proved, probable, and
possibly reserve P10 is 4.3694 billion stock tank barrel. The material balance equation
cannot be used before the production stage, while the Monte Carlo simulation can be applied
before that.

Sustainable cell tower design is essential for minimizing the environmental footprint of
expanding telecommunication networks, which traditionally prioritize signal coverage over
sustainability. This study addresses this gap by proposing a holistic framework that
integrates standardized sustainability metrics, advanced energy management systems, and
modular design principles. The research aims to minimize environmental footprint while
ensuring scalability and cost-effectiveness. A multi-criteria decision-making (MCDM) model
is developed to evaluate designs based on energy consumption, carbon emissions, lifecycle
costs, and adaptability. The model was validated against operational tower data with a 5.4%
Mean Absolute Percentage Error (MAPE). Simulations and a detailed retrofit case study
demonstrate significant and substantiated improvements in energy efficiency, increased by
up to 30%, carbon emissions reduced by 60%, operational costs lowered by over 65%, and
lifecycle costs are lowered by 20%. Furthermore, the modular designs prove highly
adaptable, extending infrastructure lifespans and minimizing material waste. This research
provides a scalable, cost-effective solution for greener telecommunication infrastructure,
aligning with global sustainability goals. The framework bridges theory and practice,
offering a robust foundation for broad industry adoption, with future work focused on pilot
testing and socio-economic considerations for equitable implementation.

In recent years, the integration of production planning and control scheduling has become
a significant factor in complex and dynamic manufacturing environments. Therefore, this
paper addresses this challenge by introducing an integrated model that simultaneously
optimizes both aggregate production planning and single machine scheduling. The primary
objectives of the developed model are to minimize overall production cost, makes pan, setup
costs, and product delivery delays as key performance indicators. To solve the integrated
model, two hybrid metaheuristic algorithms are applied with a novel hybridization ratio
(40%-60%): the Hybrid Whale Algorithm with the Fruit Fly optimization algorithm and the
Whale Algorithm with the Grey Wolves Optimization Algorithm. Large set of computational
experiments are conducted on 10 instances with 20 to 200 jobs and 100 planning periods,
with 30 independent runs. The results show that both hybrid algorithms are highly effective
in finding near optimal solutions to the integrated complex problem. Comparative analysis
demonstrates that the hybrid algorithms outperform common algorithms (Whale, Genetic,
Fly, and grey wolf) and the dynamic programming method in terms of solution quality,
convergence speed, and computational stability in most tested scenarios. These findings
provide practitioners with robust decision-support tools to improve operational efficiency
in modern manufacturing systems.

Previous studies have demonstrated the effectiveness of microbially stimulated calcite
precipitation (MICP), produced by specific bacterial species such as Bacillus spp. , as a crack
repair agent in cementitious materials. To explore its potential applications, this research
investigated the effect of a bacteria-based self-healing agent on concrete containing recycled
brick aggregate. The study involved isolating and culturing bacteria, identifying their
species, inducing cracks, adding the bacteria, and measuring the repair efficacy of Bacillus
spp. Specifically, isolated bacteria were added to samples of solid pavement composed of
recycled brick aggregate, and cracks of varying sizes were created. Using 16S RNA
sequencing, the characteristics of Bacillus spp. were determined. The bacteria were
identified as alkaline and heat-tolerant, with amplified fragments measuring 1500 base
pairs. Statistics revealed that self-healing does not always occur at the highest bacterial
concentrations. Bacillus spp. produced the greatest amount of calcite at an optical density
(OD600) of 1.0.X-ray diffraction (XRD) analysis indicated that Bacillus spp. can form two
major components of calcium carbonate: calcite and aragonite. These results suggest that
optimal bacterial concentration is necessary for effective repair, as varying calcite
depositions were observed in concrete samples with different bacterial concentrations

To protect digital audio transmissions from unauthorized access and modification, this
paper proposes a voice encryption scheme based on chaotic systems. The proposed
approach combines multiple chaotic maps into a cryptographic scheme that is applied at the
byte level. The input sound is first divided into four equal-length parts. The Rossler system,
Lorenz system, Henon map, and Baker map are chaotic systems used to encode each
fragment. Four segments are combined, and subsequently, a logistic map is applied to the
encoded audio to introduce a flipping step, ensuring a strong spread and confusion
throughout the entire signal. During the decoding phase, XOR processes and switching are
systematically reversed using saved keys, restoring the original audio. The encoded and
retrieved audio is evaluated using several tests to ensure the success of the encoding and
retrieval process, such as the signal-to-noise ratio (SNR) test, autocorrelation, mean square
error (MSE), histogram analysis, and spectrogram comparison. The results demonstrate that
the proposed system is highly secure against attackers and possesses a powerful diffusion
and confusion mechanism, enhancing speech communication in the field of communications.
Hence, the system is suitable for multimedia applications that require an elevated level of
confidentiality, including th

This study intends to evaluate the accuracy and reliability of satellite data from the NASA
POWER project in capturing important climatic variables, which are precipitation and air
temperature, compared with data collected from the National Climate Data Center (NCDC)
ground-based weather stations located in the Khassa Chai River basin. The basin has a
topographic gradient beginning on the northeastern highlands and sloping towards the
southwest. The Khassa Chai River Basin experiences a semi-arid climate, with hot, dry
summers and relatively cold and wet winters. Daily precipitation and temperature records
(2010–2024) were collected from four weather stations, in addition to records from the
NASA POWER recording at the nearest grid points. To evaluate the reliability of the datasets
from NASA POWER, this study used several relevant statistical indicators (i.e., the coefficient
of determination (R²), correlation coefficient (CC), Nash-Sutcliffe efficiency (NSE), mean bias
error (MBE), and root mean square error (RMSE)) at daily, monthly, and yearly time scales.
The analysis of precipitation indicated an excellent fit between the NASA POWER satellite
data and in-situ data. For monthly comparison, the R² was 0.89, and the CC was 0.94, while
for annual comparison, the R² was 0.81, and the CC was 0.88. Overall, the fit improved with
longer time scales, which indicates the ability of the satellite data to accurately capture
precipitation trends over time. The range of NSE values from 0.72 to 0.87 also reinforces the
ability of the data to reproduce precipitation changes over time.

The construction industry is a major contributor to resource depletion, environmental
degradation, waste production, and greenhouse emissions, which makes it necessary to
adopt alternative development models. The Circular Economy (CE) has become one of the
potential strategies of resource conservation, waste reduction, and environmental
equilibrium restoration. This paper aims to provide a systematic literature review of the CE
principles by analyzing research papers and articles in scientific journals and some
university theses, encompassing the R-Principles (Reduce, Recycle, Reuse, Refuse, Rethink,
Repair, Repurpose, Remanufacture, And Recovery), together with principles related to
design and production, use and consumption, management and policies, as well as
innovation and technology principles. Moreover, examines barriers to the implementation
of CE and indicators of assessment. The results show that the adoption of CE in the
construction industry is multidimensional and comprises eight broad categories, namely:
Political, Economic and Market, Social and Cultural, Technical, Technological, Informational,
Administrative, and Environmental Barriers. In addition, the review highlights
fragmentation and inconsistency in existing circularity indicators across economic,
environmental, and social dimensions. Collectively, the analyzed literature indicates that
even though a variety of principles of a Circular Economy can be found, there is still a limited
implementation due to the ongoing structural barriers and disjointed approaches to
evaluation. The literature review identifies a recurring discrepancy between the theory of
the Circular Economy and its practical implementation in the construction industry.

Accurate prediction of electromagnetic moments in odd-A nuclei near doubly magic cores
is challenging due to their sensitivity to core polarization and single-particle structure. This
study investigates the predictive performance of Skyrme-HFB (SLy4) against shell model
(SM) calculations for quadrupole moment (Q20) and magnetic dipole (M10) in the selected
nuclei (17O, 17F, 39Ca, 39K, 47Ca, 49Sc, 131In, 133Sb, 133Sn, and 209Bi) near doubly magic cores
using the Hartree-Fock-Bogoliubov (HFB) method and the SM method. The SLy4 interaction
was used in HFB calculations. On the other hand, SM calculations were performed in sd, sd
pf, fp, and jj shells using USDC, SDPF-U, GXPF1A, jj45pn, and sn100pn interactions. The
calculated results of both methods were compared with experimental data from the
IAEA/INDC nuclear datasets. For Q20 Skyrme-HFB predicted the correct sign with minor
deviations in the value of light nuclei (e.g., 17O, 17F, 39Ca, 47Ca) by about −7% to +6%, but for
heavier nuclei like 39K and 49Sc the deviation is much higher about (-88% and -85.7%), and
for nuclei around 132Sn and 208Pb cores (131In, 133Sb, 133Sn, 209Bi) the deviation was also high,
ranging from -81% to -96%. Meanwhile, the SM Q20 results showed a significant
improvement, with a deviation of 1-16% for the whole set. For M10, HFB calculations were
close to experiment for light nuclei (17O and 17F) with deviation (0.99% and 1.53%),
respectively, and reasonable for nuclei like (47Ca ≈ 4.5% and 39Ca ≈ 11.5%), but deviated
strongly for 39K by -73.87%. M10 for heavier nuclei was not evaluated within HFB in the
present work. SM calculation reproduced M10 with absolute percent deviations of (0.03% −
29.23%) across the studied nuclei (median |∆%| ≈ 8.09%), where the lowest |∆%| values
were 17F (0.03%), 209Bi (0.29%), 39K (0.38%), and 17O (0.87%), while the highest |∆%| values
were 39Ca (29.23%), 133Sn (25.53%), and 133Sb (23.33%).

Shrinkage and Creep, especially in light-weight concrete, are recognized as complicated
phenomena that significantly impact the serviceability of concrete. This may be attributed
to the significant influence of the surface layer's behavior at the interfacial transition zone
(ITZ) between the aggregate and the surrounding cement paste on shrinkage and creep
phenomena. In this article, the short-term creep and shrinkage of structural lightweight
aggregate (LWA) concrete up to 90 days were studied. The concrete was made with a
combined coarse and fine perlite aggregate, and the water cement ratio (W/C) was 0.4. Two
types of fibers were used: polypropylene and recycled copper wire. Additionally, metakaolin
was used as a pozzolanic material. Results indicated that the creep and shrinkage of
reinforced concrete is lower than that of lightweight concrete without fiber. The total
shrinkage of the MF mix was (1098.5×10-6), comparable to (1229×10-6) of the reference mix
(RM) after three months. However, the total creep was (1991×10-6) of the fiber mix (FM)
equivalent to (2596×10-6) of the RM after three months. The elevated creep and shrinkage
values of the lightweight concrete (LWC) mixtures resulted from the increased porosity of
the (LWA) used and the release of moisture retained inside the particles owing to their
prewetting during the mixing process.

The impact resistance of bimetallic materials is a critical aspect of engineering, particularly
in the aerospace and automotive industries. Notched geometries are often encountered in
real-world scenarios due to manufacturing defects or intentional design features. The
present work investigates the impact resistance and fracture behavior of Al/Cu bimetallic
sheets, focusing on the influence of notches on fracture energy, the fracture process zone,
and overall failure mechanisms. For interpretation and analyses purposes, the impact test
results were integrated with SEM fractographic analysis and the Essential Work of Fracture
(EWF) framework. Four notch dimensions of U and V geometries were tested. Experimental
results indicated that U-notches yielded higher fracture toughness and lower stress
concentration factors. Conversely, V-notch specimens experienced a 32.5% reduction in
toughness and a 25.5% increase in stress concentration as notch depth increased. Also, the
Analytical EWF predictions showed good agreement with experimental data provide that
Al/Cu obey the fracture ductile behavior. The SEM images emphasized on the ductile
fracture nature of the Al/Cu sheet, and U-notches reveal a wider and rougher fracture area
shows larger FPZ. As well, as the Al layer exhibited ductile plastic deformation, while the Cu
layer showed brittle cleavage and acted as a structural hinge to arrest cracks. These findings
provide critical insight into enhancing the use of bimetallic metals under dynamic loading,
establishing a basis for future investigations into the relationship between bimetallic
parameters and fracture behavior.

Time and cost overruns are problems that persist in projects involving transportation
infrastructure, especially in developing regions. This research examines the empirical
relationship between time inflation (TI), which is defined as the percentage increase in
project duration from the original schedule, and financial inflation (FI), which is defined as
the percentage increase in project cost from the original budget for road and bridge projects
in Iraq. The problem that the research aims to cover is the escalation in project costs
associated with time inflation, with the aim of quantifying this relationship to aid in project
planning and risk management. Using a quantitative method, data from 18 completed
projects were analyzed using descriptive statistics, Spearman's rank correlation (ρ), and
simple linear regression. The results show a very strong positive monotonic relationship
between TI and FI (ρ = 0.743, p < 0.01). Regression analysis shows that the TI variable can
explain about 32.9% variance in the FI variable (R2 = 0.329), and 1% increase in the TI
variable can lead to an average increase of 0.556% in the FI variable. The study concludes
that although time inflations are a significant cause of financial inflation in Iraqi road and
bridge projects, there are other factors that have a significant influence on financial
outcomes. These findings highlight the need for proactive schedule control as a basic cost
control strategy and suggest improved contractual and monitoring structures to reduce the
financial consequences of delays.