Journal of Engineering

With an emphasis on individuals with Type 1 diabetes, this study reviews blood glucose
management techniques during the last five years. A brief introduction is provided to show
how this biological issue turns out to be a control system issue in terms of plasma blood
glucose management. This paper discusses new research on automated insulin delivery
using the Bergman mathematical model. An attempt has been made to undertake a
systematic review of the research that has been done so far in the development of artificial
pancreas systems. The conclusion describes the development of a cognitive glucose-insulin
controller and provides a fundamental grasp of how the nonlinear Bergman model for
blood glucose regulation can be used to establish a control system for this biomedical
control challenge. When compared to other current methods, the proposed cognitive
controller shows a quicker response in terms of blood glucose maintenance. Additionally,
the comparison results demonstrated that the suggested cognitive glucose-insulin control
algorithm improved the time to reach a normal physiological blood glucose level for the
first patient by 10% compared to the fuzzy logic and the fractional-order PID control
algorithms, by 25% compared to the type-2 fuzzy control algorithm.

Reducing friction between orthodontic components, such as archwires and brackets, is
crucial in contemporary orthodontic treatments. Coating these components is a significant
method to achieve this goal. This research is aimed To investigate the tribological
performance of nanocoated 316L stainless steel (SS)—one of the most widely used alloys in
orthodontic archwire manufacturing—coated with vanadium (V), tantalum (Ta), and
niobium (Nb) via plasma sputtering at varying time intervals (1, 2, and 3 hours) under wet
conditions simulating an oral in-service environment, which is unexplored previously in the
existing literature. Using a computerized tribo-system applying 1 N for 20 minutes on coated
SS substrates, the common alloys for orthodontic archwire manufacturing. Results: The
results indicated that the coefficient of friction (CoF) increased generally under wet
conditions as a result of hydrogen bonding and capillary adhesion. Ta emerged as the
preferred coating, demonstrating substantial friction reduction compared to Nb and V. V was
found to have a negative tribological impact. This work concluded that Coating 316L SS with
Ta was identified to improve tribological behavior in wet conditions that simulate an oral
environment, potentially minimizing the duration of orthodontic treatment and promoting
efficient tooth movement.

Innovative structural supports, known as skirted foundations, are primarily employed in
offshore engineering. Skirted foundations extend below the footing like conventional
shallow foundations and carry loads to deeper soil layers. A "skirt" is a wall that surrounds
the foundation from one side or more, is connected to the foundation, and functions as a
single unit. These skirts are essential for improving overall stability and transferring loads
to more stable subsurface layers, which improves the foundation's performance. Significant
features of skirted foundations make them promising for economics and appropriate for use
in constructions with large loads and poor soil conditions. It has been demonstrated that
skirted foundations are a more effective alternative to conventional foundations like piles,
piers, etc. It is regarded as economical because of the reduction of employing building
materials, less machinery, and a smaller workforce, as well as the saving of time necessary
for installation. This review paper summarizes previous experimental and numerical
investigations on skirted foundations and surveys their characteristics; the important
conclusions can be summarized: The ratio of skirt length to foundation width (2) gave the
best results in improving bearing capacity and minimizing settlement. The ultimate load
increased when the skirt inclination increased from 10° to 30° because an attachment area
was established between the inclined angle and the soil. Circular skirts can result in higher
bearing capacity and lower settlement than square skirts when both are placed under
comparable conditions. Also, skirted foundations are suitable for supporting shallow
foundations in seismic zones.

Seepage under earthen dams is considered a major factor in their stability. Statistics showed
that 40% of dam failures are caused by foundation seepage. In this study, the finite element
method was used to calculate the amount of seepage under (Haditha Dam, located on the
Euphrates River. A simulation model was created for each decade, and the seepage amount
was calculated for three decades. The results showed a match in the values and that the
amount of seepage between the first and second decades increased by (0.000022 m3/s) or
(7.62%). Seepage increased between the second and third decades by (0.000056 m3/s) or
(17.89%). This increase is considered small for three decades and does not affect the dam's
stability. Therefore, with climate change and the decline in water supply sources, it is
necessary to address this issue and find the best solution.

There are numerous real-world applications for delay differential equations, including
engineering model systems with time delays, such as control systems and communication
networks, time-limited meals, blood pressure, hemopoiesis, and others, especially when the
oscillation in these equations is exploited. To fulfill the goal of this study, certain of the
coefficients in the first-order logistic equation must be piecewise continuous. This can only
be accomplished by using the delay differential equations with the piecewise constant
argument to investigate the oscillation or nonoscillation property of all first-order logistic
equation solutions. The solution's piecewise constant is the largest integer function. Using
techniques such as transforming the non-linear delay differential equation to a linear delay
differential equation and then using integral inequality, we provide adequate circumstances
for all solutions to oscillate. To ensure all solutions, required and adequate conditions have
been defined. After that, looking at an example shows how the oscillation of the food-limited
equation. Also, the figures appearing at the end of examples show more explanation.

There is a continuous demand in geotechnical engineering to find more economical footing.
Screw piles provide acceptable or even much more bearing against tensile, compression,
lateral, and overturning moment loads with less impact on the environment and
surrounding buildings. Screw piles may be utilized either as shallow footing or deep footing,
and can be installed in various types of soils except the soils that contain gravel or stiff clay.
A screw pile is generally made of high-quality steel shaft with a single helix plate or multiple
helixes plates attached to the lower end of the shaft at specified spacing utilized by the
designer. The current study highlighted the various theoretical and field methods that were
utilized in literature to estimate the uplift capacity of screw piles and pointed out several
field, laboratory scale, and numerical simulation studies that investigated the most
important parameters during installation and uplift loading of the screw piles. The former
investigations revealed that installing the screw piles with torque rotation speed (v) of 1
(p/r) provides higher uplift capacities as well as increasing the embedment depth, the helix
diameter, and the number of helical plates welded to the screw pile shaft. In general, the the
decrease in the spacing ratio (S/D) gave higher uplift capacity in almost all the soils used by
researchers this case can also be said to the decrease in the (L/D) ratio. Finally, increasing
the undrained shear strength of clayey soil and the relative density of sandy soil gave a
higher uplift capacity.

Metal foam has recently been used in many engineering applications, such as solar
collectors, heat exchangers, and cooling of electronic devices, which calls for studying
different cases of using metal foam in these applications. The current study conducts a
numerical analysis of heat transfer and fluid flow characteristics for air in a rectangular
channel filled with high-porosity copper foam. The study examined the thermal performance
for two cases of gradient pore density, which are arranged as (10-20-40) PPI and (40-20-10)
PPI. These cases were compared with two other cases for constant pore density, 10 and 40
PPI, and empty cases. The ANSYS FLUENT 20.0 employed the Darcy-Forchheimer extended
Brickman model in the two-dimensional domain with the local thermal non-equilibrium
model (LTNE) for the energy equation to obtain the numerical simulation for this study. The
working parameters included air with Re from 200 to 2100 and applied heat flux from 450
to 6000 W/m2. The results indicated that employing metal foam with a low pore density led
to a decrease in both the Nusselt number and pressure drop. Both gradient cases exhibited
Nusselt numbers and friction factors that fell within the range of the constant PPI cases, but
one of the gradient cases increased the performance factor by 10%. In general, the PPI
configuration of 10-20-40 exhibited a higher heat transfer coefficient in comparison to the
40-20-10 PPI arrangement with the same pressure drop.

We present a theoretical framework combining exponential growth dynamics and
Michaelis-Menten kinetics to model the interaction between tumor density and drug
concentration delivered via an infusion pump. The model accounts for the saturation of
tumor growth inhibition at high drug concentrations, reflecting biological saturation effects.
Continuous infusion chemotherapy is highlighted as a superior delivery method,
maintaining consistent drug levels at the tumor site while reducing systemic side effects
compared to conventional bolus methods. The framework provides a predictive tool for
determining the critical drug concentrations and tumor densities required for tumor
elimination while minimizing adverse effects. Stability analysis, based on solving nonlinear
equations, identifies equilibrium points that represent steady states of tumor density and
drug concentration. The stability of these points is examined to assess the long-term
effectiveness of chemotherapy regimens. Illustrative numerical simulations demonstrate
how variations in drug delivery rates, tumor properties, and kinetic parameters influence
therapeutic outcomes. Key factors such as the minimum drug concentration needed to
suppress tumor growth and conditions for tumor eradication or regrowth are identified.
Sensitivity analysis further reveals how parameter changes affect system stability and
outcomes, offering insights for optimizing dosing strategies. This framework bridges
theoretical modeling and practical challenges in cancer chemotherapy, providing a versatile
tool for understanding and improving treatment strategies. It can be adapted to various
tumor types and treatment modalities, supporting advancements in personalized medicine
and future cancer therapy research.

This study examines the behavior of fatigue crack propagation in aluminum alloy sheets
used in aircraft wings, with a particular focus on critical angles of attack (AOA). The widely
utilized aluminum alloys 2024-T3 and 7075-T6 were analyzed to determine the effects of
varying AOAs, representing normal flight (5°) and takeoff/landing (10°) on crack growth
rates. A comprehensive approach was adopted, integrating experimental testing, numerical
simulations, and analytical modeling. Experimental methods included material
characterization and multiaxial fatigue tests using an innovative apparatus. Numerical
simulations conducted with ANSYS 2021 CFD evaluated stress distributions and crack
propagation under different wind loads and AOA conditions. Analytical modeling applied the
Paris-Erdogan equation and fracture mechanics principles to predict crack growth behavior.
The results revealed that higher AOAs significantly accelerate crack growth in both alloys.
Notably, AL2024-T3 demonstrated slower crack propagation than AL7075-T6, indicating
superior fatigue resistance, especially at lower AOAs. The fracture growth rates were
determined to be 0.005 mm/sec for AL2024-T3 and 0.009 mm/sec for AL7075-T6. These
findings have important implications for aircraft design, maintenance, and material
selection. They underscore the necessity of accounting for AOA-dependent fatigue behavior
to improve the durability and safety of aircraft structures.

The worldwide construction industry has recognized the necessity for lightweight building
materials that are flexible, high-performance, and environmentally friendly. In response to
this need, lightweight foamed concrete (LFC) is being proposed. In concrete, nanoparticles
are utilized for their beneficial effects, such as their small particle size and high reactivity,
which improve the strength of concrete. In this study, foam concrete block waste was used
as a partial substitute for cement in the manufacture of foamed concrete. The experimental
program was done by preparing finally ground foam concrete wastes by using specific
machines to produce particles similar to cement particles. The replacement ratios are (0, 10,
20, and 30) % by weight of cement and the TiO2 ratio was 0.5% for all mixes. The mechanical
properties, including compressive and tensile splitting strength, were examined at 7 and 28
days. Results indicate that FCBW decreases mechanical and durability properties due to
increased porosity and reduced cement content at higher replacement levels. The findings
show that adding more FCBW lowers compressive and tensile strengths, while mixes M1 and
M2 keep strength ratios near the reference mix. However, a mix containing 10% FCBW and
0.5% nano-TiO2 offers a promising mechanical performance.

This study is important since it investigates the effectiveness of sediment removal near
hydropower intake by flushing. The method can replace the current expensive method for
sediment removal by dredging. The sediment transport mechanism, maximum scour depth,
volume, and scour area at the upstream of a cross-river structure model with different outlet
configurations were investigated. The investigation included a series of experiments
conducted in a laboratory on a 12-meter-long, 0.30-meter-wide, and 0.45-meter-deep flume.
The shapes of the model outlets were circular, semicircular, and a three-quarter circle of the
same diameter (D=11 cm). The cross-river structure was installed at the end of a 2 m
working section with uniform sediment of median size(d50) of 0.23 mm and geometrical
standard deviation (σg) of 1.29. The total depth of the sediment in the working section was
10 cm. The collected data showed that the maximum scour volume was 1194.98 cm³ with
the circular outlet, while with semicircular and three-quarter circle outlets was found to be
613.48 cm³ and 640.136 cm³, respectively. Compared with the scour volume upstream of
the circular outlet (D=11cm), results showed that the scour volumes were reduced by 48.6%
and 46.4% for outlets with a semicircle and three-quarter circle, respectively.

Overheating is a common issue in a nonparallel helical gearing system. The reason is the
high friction, sliding velocity, and tangential force that occurs between meshed gear teeth.
These factors can result in negative outcomes such as increased power loss, low gear
efficiency, breakdown, and scuffing. Two types of non-parallel helical gears have been
utilized to estimate the meshing heat fluxes of a pair of non-parallel gear systems. The
scenario involves a design of standard helical teeth and a modified asymmetric non-parallel
helical system. The asymmetric tool designe serves as a reference for preparing a modified
asymmetric helical gear, which the CNC machine can then cut. The hybrid curve has been
compounded from three parts (hypocycloid-involute-tip relief) on the loaded side and
(hypocycloid-involute-epicycloid) on the unloaded side, using different pressure angles for
each side. The non-parallel helical gear drive that has teeth modified asymmetrically is
better than a standard non-parallel helical gear drive. The numerical results indicate the best
enhancements in the maximum contact stress and tooth root stress percentages are about
12.253% and 8.91%, respectively. Adjusting the helical gear teeth surface improves the
generated heat flux, resulting in an enhancement percentage of approximately 39.567%. The
enhancement percentage of pitch deviation under different rotational speeds has been the
best compared with the standard case under the same conditions and a high-speed range
with high local temperatures reaching about 15% and is good at the low-speed range by
10%.