Journal of Engineering

This study investigated the potential of calcined clays from Nigerian deposits in
the production of ternary blends of cement. Clay samples were obtained from three different
locations namely: Ikpeshi, Okpilla and Uzebba. The raw clay samples were then calcined at
700°C and 800°C. Chemical and mineralogical compositions were determined for the raw
and calcined clay samples using XRF and XRD respectively. The chemical composition
confirmed these clays as potential pozzolans with SiO2, Al2O3, and Fe2O3 collectively
exceeding 70%. XRD analysis identified kaolinite and quartz as major mineral phases in the
raw clays, which transformed into metakaolin upon calcination. Compressive strength tests
on mortar samples prepared with 50% substitution of Portland cement with the calcined
clay and limestone, showed that Ikpeshi clay at 800°C had the best strength performance,
with a strength activity index of 0.92 at 28 days, demonstrating superior pozzolanic
potential. Strength development was more significant between 7 and 28 days, indicating the
pozzolanic reaction's contribution to long-term strength. However, the initial strength at 3
days was lower than the reference cement due to a delayed pozzolanic reaction. XRD analysis
of blended pastes revealed typical hydration phases like portlandite, C-S-H, Strätlingite, and
ettringite, with the ternary blends showing reduced portlandite content, indicating
absorption by the pozzolan's alumina phase. Durability assessments revealed that the
ternary blends exhibited improved resistance to water and chloride ion ingress. These
findings highlight the effectiveness of Nigerian calcined clays in producing durable and
sustainable concrete, supporting their use as supplementary cementitious materials to
reduce the environmental impact of concrete production.

Reactive powder concrete is an attractive new concrete technology for structural design
applications. The technology has been used for different structures with several advantages.
Strengthening and retrofitting structures using FRP has grown rapidly in the last decades to
upgrade structures because of the gradual material degradation over time. The technique
was applied mainly for conventional normal and high-strength concrete and steel. This study
is conducted to study the performance of bonding interface among reactive powder concrete
substrate and CFRP sheets using different parameters, including bond length, bond width,
and bond–slip relations. Concrete prisms with dimensions of (25 x 25 x 75 mm) were
adopted in the experimental program. Five groups of three specimens were tested using a
single-lap shear test setup, and pull-out loading was applied for testing the specimens. Test
results indicated significant bonding properties compared to the normal concrete.

The study aimed to find the best amount of cellulose nanofibers to add to heat-cured
denture base material to enhance its mechanical characteristics. Cellulose nanofibers (CNF)
were added to the polymethyl methacrylate (PMMA) denture base in several weight
percentages (0%, 0.5%, 1%, 1.5, and 2%). A probe sonicator was used to mix the monomer
with the cellulose nanofibers for around 5 minutes. Impact strength, transverse strength,
and shore D surface hardness were the three groups that were classified afterward according
to the trials conducted. Descriptive statistics, including means, standard deviations, and bar
chart visualisations, were utilised to analyse the data. The findings indicate that the mean
values of impact strength and transverse strength measurements exhibited a significant
increase in the 0.5% and 1% cellulose nanofiber reinforcement groups, as compared to the
control group. However, no significant increase was observed in shore D hardness. Other
percentages (1.5% and 2% by weight of CNF) either significantly or insignificantly decreased
the mean value of the results. The findings suggest that the incorporation of cellulose
nanofibers at concentrations of 0.5% and 1% improves the mechanical properties of a
denture foundation.

Six (1000*1000 mm2) slab specimens were cast and tested as two-way simply supported
slabs previously (three under monotonic loading and three under repeated loading) are used
in this research. The tested specimens consist of one solid slab and two voided slabs with the
following variables (type of slab (solid and voided), presence of steel fibers (0% and 1%),
and the presence of GFRP layers). This paper presents the results of tested slabs and the 3D
Nonlinear finite element (ABAQUS program) is proposed to verify the tested slabs under
monotonic and repeated loading. The process of modeling the structure components of the
tested slabs will be discussed in detail, including the creation of the parts, model material
properties, surface interaction, loading method, boundary conditions, and meshing. Then,
the experimental findings will be compared to the proposed FE models. A parametric study
with new variables has been investigated that affect the behavior of reinforced concrete
slabs and is not implemented in the experimental part of this study. These specimens are
divided into two groups according to the nature of loading as in the experimental work. The
created finite element models can accurately reflect the test results with an acceptable
degree of difference in deflection and ultimate load by 10%. The crack patterns obtained
using finite element models for the investigated specimens under monotonic and repeated
loading are extremely similar to the crack patterns observed in the experimental work.

Reservoir characterization is an important component of hydrocarbon exploration and
production, which requires the integration of different disciplines for accurate subsurface
modeling. This comprehensive research paper delves into the complex interplay of rock
materials, rock formation techniques, and geological modeling techniques for improving
reservoir quality. The research plays an important role dominated by petrophysical factors
such as porosity, shale volume, water content, and permeability—as important indicators of
reservoir properties, fluid behavior, and hydrocarbon potential. It examines various rock
cataloging techniques, focusing on rock aggregation techniques and self-organizing maps
(SOMs) to identify specific and anomalous rock faces. Furthermore, the paper explores the
adoption of advanced methods, including hydraulic flow units (HFU), providing a fine
grained understanding of reservoir heterogeneity and contributing to the prediction of flow
dynamics. The final section includes structural geological models, petrophysical data
collected, rock type classification, and spatial data to better represent the reservoir bottom
structure. It provides a valuable resource for researchers, geologists, and engineers seeking
to characterize reservoirs and make optimal decisions on hydrocarbon exploration and
production. It is an important component of hydrocarbon exploration and production, which
requires the integration of different disciplines for accurate subsurface modeling.

Semi-deep foundations are a viable option when the soil under the foundation is loose and
extended to a significant depth, also, when traditional methods of improvement are not
feasible applying piles would not be a practical choice due to their high cost and time
consuming installation process. Skirted foundations are a sort of semi-deep foundation that
can penetrate the soil to a depth that is twice their width. Skirted foundations, in which a
vertical or inclined wall surrounds one or more sides of the soil mass under the footing, are
recommended methods to increase the soil's bearing capacity. The walls work to reduce
settlement while enhancing load capacity and failure depth in soils with low shear strength.
This paper discusses the previous experimental and numerical investigations conducted on
skirted foundations. Various factors were considered, including soil type, degree of
saturation, soil properties, skirt depth, and width, soil-skirt interaction, and different
scenarios of applied loads such as inclination and eccentricity. These studies have effectively
shown that skirted foundations are very successful in reducing sliding, overturning, and
settlement while also increasing foundation stability, soil capacity, and uplift capacity.

Qaiyarah oil field is characterized by its complexity due to its extra heavy oil reaching 16°
API. Thus, building a systematic PVT model for this field at a specific range of temperatures
is a powerful challenge for screening such reservoirs. The peng-Robenson equation of state
model with up to six pseudo components was developed for the crude sample of the
Qaiyarah oil field. This work represents the fingerprint for constructing a dynamic model for
the field under study. The model also applies to the heavy oil reservoirs under splitting and
lumping scenarios. This work suggests a lumping scheme to enhance the accuracy and CPU
performance of compositional reservoir simulations. Therefore, the full components model
(13 components) is lumped into a reduced number of pseudo components (6 components)
to be utilized in the compositional fluid simulation. This study outlines the Peng-Robinson
equation of state (EOS) to tune the data at a certain pressure range up to 400 psi. More
specifically, various essential parameters have been trained to match the model results with
the experimental data. Splitting processes of C6+ into four pseudo components, namely,
HYP01, HYP02, HYP03, and HYP04 is added to the matching picture. Separately, justifying the
critical properties introduced a better result of regression. The results showed an acceptable
match for Bo with an error percent below 1%, while calculated oil viscosity deviated from
measured values in different ranges against pressure variation.

Land use is the human modification of the natural or terrestrial environment into a built
environment such as fields, pastures, and settlements. Baghdad, like most cities in the world,
suffers from many urban problems, especially the problems associated with the disparity in
the distribution of land uses and deficiencies in their distribution according to scientific
standards and foundations, such as the problem of pollution and overpopulation. Karrada
was chosen because it represents a large urban center in Baghdad, with about 1 million
people spread over about 72 km2. The aim is to assess land use in Karrada. In addition to
the analysis of land uses in the study area, and the study of changes that occurred in those
uses, either the study methodology has adopted the descriptive and analytical approach
based on the data and information obtained from the municipality of Karrada. Comparison
was used as a method of evaluation and geographic information systems (GIS) technology
was used to achieve the set objectives. The research lasted almost a year, and the study found
that the land uses in Karrada are far from what they were designed for and from planning
standards, as it was found that agricultural use decreased significantly, and its lands turned
into other uses such as residential and institutional use. Creating land use maps for the years
1973 and 2022 was one of the most important results of this study in conclusion, the study
called for several recommendations Among them is the need to adhere to planning standards
for land uses to achieve spatial justice in the distribution of those uses and to benefit from
the experiences of countries in the field of land and investment promotion.

The effect of the addition of sustainable materials and alkali-resistant glass fibers on perlite
concrete is studied in this paper. The research includes slump, density, flexural strength, split
tensile strength, compressive strength, and thermal conductivity tests. This specimen was
cast using Portland cement, metakaolin (which replaced 15% of the cement weight as
pozzolanic materials), a combination of coarse and fine perlite aggregate, superplasticizer,
and local ash (which was employed as a filler and replaced by cement weight in a ratio of
10%). The ratio of cement to perlite (volumetric ratio) was 1:2. The concrete reinforced 1%
alkali resistance glass fibers by volume of concrete. The results show that adding sustainable
materials to the concrete increased its cylinder compressive strength by a percentage of
(57.75%, 41.76%, and 44.82%) for 7,28 and 60 days, respectively and both tensile and
flexural strength increased at a ratio of (37.28%, 30.33% and 34.5%), (36.05%, 68.22% and
56.52%) respectively at (7,28 and 60 days). And including alkali-resistant glass fibers
increases the compressive, tensile and flexural strength in a ratio of (61.5%, 43.58%,
47.45%), (61.54%, 44.08% and 52.71%) and (113.95%, 124.3% and 97.85%) respectively
at (7,28 and 60 days), compared with reference mix. The density increased by adding
sustainable materials and fibers but stayed within the limitations of structural lightweight
concrete (ASTM C330). The thermal conductivity also increased after adding sustainable
materials and glass fibers compared with the reference mix, but it was within the constraints
of insulation concrete.

A new model for the non-linear propeller-pendulum system is derived in this study. The
model takes into consideration the effects of external disturbances and the properties of the
pendulum elements. Two systems with PID controllers are simulated. In the first system,
Simulink is used to implement the system and tune the PID parameters. In the second
system, a MATLAB script is used to simulate the system and tune the PID parameters. The
scrip uses the Runge-Kutta method for solving the system’s equation and uses particle
swarm optimization (PSO) to tune the parameters. Further, both systems were investigated
under two disturbance conditions. The performance of these systems is evaluated based on
comparing the settling time, the peak overshoot, and the integral of the absolute errors (IAE).
The results show that when there is no disturbance, both systems are capable of tracking the
desired signal successfully. However, the results also show that the application of
disturbances causes the first system to lose its smooth response. In contrast, the second
system demonstrates a robust response and effective countermeasures to disturbance
effects. The results of unit step disturbance are as follows: the settling time, peak overshoot,
and IAE of the first system are 13.16s, 11.6%, and 1.706, respectively. Further, the settling
time, peak overshoot, and IAE of the second system are 2.388s, 6.6%, and 0.299, respectively.
It can be concluded that Simulink is not recommended to be used for tuning the PID
controller in the presence of disturbances.

Using asphalt mixtures with added materials became a significant field for enhancing
asphalt properties. Crumb rubber or recycled tire rubber is one of these materials that
gained great attention because it provides asphalt mixtures with enhanced properties and
with the privilege of being economically and environmentally efficient where it reduces the
waste tires from being disposed to nature. This study explores the latest articles in this field
with a focus on different methods used to incorporate crumb rubber (CR) into the asphalt
matrix. It has been noticed that most articles focus on the wet process for incorporating CR
into asphalt. This method is known for its efficiency, but it consumes less CR as compared to
the dry process. The dry process deals with CR as a substitute rather than an additive, but it
is used less around the world in enhancing asphalt properties where it has less effect on
asphalt characteristics development. The third method (terminal) is a mix between the
mentioned methods and comprises the prospectives of both methods. The need for this
research is underscored by the growing environmental and economic challenges associated
with waste tire disposal and the continual degradation of road infrastructure. This study
contributes to developing more sustainable, durable, and cost-effective road paving
solutions by exploring the efficacy and methods of crumb rubber integration into asphalt.

Morphological structures of urban streets in Baghdad have been deciphered by using
practical methodologies inclusive of data collection, digitization, and identification
processes. This paper uses street pattern morphological analysis in a typical Middle Eastern
city, in this case, Baghdad, from organic configurations to modern metropolitan sprawl. It is
based on historical maps and satellite images, supported by field surveys. Six distinct street
patterns have been identified that have influenced the formation of Baghdad’s urban
development and continuity, focusing attention on the ancient city configuration and current
planning principles. Of great interest is the fact that there are calls for the retention of the
urbanism historical fabric in the cities with new growth at the same time there are calls for
methodologies that are responsive to the sociocultural energy characteristic of the cities in
the Middle East. This study adds to the general body of literature on urban morphology and
further provides detailed insight into the morphology of streets in Baghdad and other similar
towns. The research, therefore, shows evidence of the need for recognizing street
morphology roles in the form and function of urban landscapes and will advocate for
environments reflective of historical context in line with the needs that modern urban life
requires. Results will demonstrate how streets change based on influences from culture and
socio-economic factors. They conclude that streets developed in the light of cumulative
processes, directions, and scales of development. This research is taken up to comprehend
urban morphology leading towards sustainable and culturally responsive designs.