Articles in This Issue
Abstract
Bitumen is a standard material for road infrastructure that is black in color, sticky, and thermoplastic in nature. It is well-known for its many applications. Due to rising traffic, global warming, and the constant introduction of new pavement varieties, forecasting road life has become increasingly complex in recent years. At the same time, a significant quantity of vehicle tires and waste engine oil (WEO) from different cars are dumped into the environment as hazardous waste. Additionally, it has been challenging to manage heavy metals and the substantial costs associated with their sustainable treatment. Therefore, this study looks at how Waste Engine Oil (WEO) and Crumb Rubber Modifier (CRM) affect the characteristics of PEN60-70 asphalt binder. The asphalt binder has been subjected to several tests at different temperatures due to the use of various concentrations of CRM and WEO. To reduce the usage of virgin bitumen (VB) and make bitumen a sustainable material, this study investigates modified bitumen using a waste crumb rubber modifier (CRM) combined with WEO. These WEO concentrations (5% and 10%) and CRM concentrations (0%, 4%, 8%, and 12%) were used in the characterization of modified bitumen, and then the characteristics of virgin and modified bitumen were compared. According to the study, adding WEO to CRM-modified binders reduces softening points by increasing penetration, as well as viscosity and workability, while CRM enhances rutting resistance. Nevertheless, the incorporation of WEO has a detrimental effect on the binder's ability to resist rutting. The study's findings also indicate that the use of WEO and CRM can enhance the resilience of asphalt mixtures to low-temperature cracking. According to the study's findings, adding WEO to co-modify CRM binders significantly reduced their softening point and viscosity values, making them easier to work with. Ultimately, the modified asphalt was found to exhibit positive rheological and physical modifications in the bitumen.
Abstract
The annular geometry with inner cylinder eccentricity and rotation is significant in many thermal and engineering fields, particularly with non-Newtonian fluid flows. A numerical analysis examines the effects of rotation and eccentricity of the inner cylinder on the fluid flow and heat transfer characteristics of shear-thinning non-Newtonian fluids within annular geometry under developing steady laminar flow. The computational model simulates non-Newtonian annular flow using a power-law viscosity model for generalized Reynolds numbers ($100\le Re_{g}\le1000$), flow behavior index ($0.2\le n\le0.8$) and Taylor number $Ta=10^{4}$ with radius ratio $r^{*}=0.5$. The simulation employs hydraulic and thermal boundary conditions, including an adiabatic outer cylinder and a constant temperature at the inner rotating cylinder, while the outer cylinder remains stationary. Results show that axial flow at $n=0.2$ exhibits lower flow resistance and enhances convective transport compared to higher $n=0.8,$ especially for the concentric case $(\epsilon=0)$. However, increasing eccentricity from $\epsilon=0.2$ to $\epsilon=0.6$ alters the heat transfer behavior, with $n=0.8$ yielding the highest Nusselt numbers at $\epsilon=0.6$, due to the strong secondary flows and intensified local acceleration in the narrow gap. These outcomes reveal that heat transfer enhancement is not solely governed by flow resistance but is also influenced by secondary flows, boundary layer stability, and localized acceleration effects.
Abstract
The flow rate of water in a pipeline system significantly affects hydraulic efficiency, water quality, and infrastructure durability. This study examines flow velocity distribution in the water distribution network of Ramadi City, Iraq, using advanced modeling techniques with WaterGEMS and GIS. The field data was analyzed to identify areas with low flow velocities, which can cause sediment buildup and bacterial growth. Our findings show that about 28.57% of the network has velocities below $0.5\text{ m/s},$ indicating limited connections and higher pressure in these pipelines. Meanwhile, 48.98% of the network operates within the optimal range of 0.5 to $2.0\text{ m/s},$ while 22.45% exceeds $2.0\text{ m/s},$ which can lead to pressure loss and pipe deterioration. Low average daily demand results in moderate flow speeds in some pipelines, increasing the risk of stagnation and negatively impacting water quality. Maintaining adequate flow rates is crucial for protecting water quality and ensuring efficient operations. This study highlights how integrating GIS with WaterGEMS can improve the assessment of water distribution infrastructure issues.
Abstract
Uncontrolled garbage disposal related to urban settings can be extremely harmful to the health of individuals as well as the environment. This paper proposes the construction of an intelligent surveillance system based on the YOLOv5 object detection model and an ultra-convolutional net (U-Net), which we will call (YOLOv5-U-Net model), capable of monitoring waste management facilities in real-time through image processing and artificial intelligence. An illustration of an intelligent surveillance system is provided in the following statement. Besides identifying different categories of garbage and possible risks to public health, the system can also identify situations of unsuitable accumulation of waste. For that purpose, to ensure that local authorities will act in due time, the framework integrates several technologies, including object detection algorithms, classification networks as well as real-time warning systems. It is through the amalgamation of these technologies. Testing of the prototype has elicited an outcome; that accuracy related to waste categorization has increased, while reaction times have decreased, all discovered due to prototype examination. Implementation of this strategy does not only increase the linkage between environmental monitoring as well as protection of public health but also gives some help in promoting a conscious urban development, right through ensuring health.
Abstract
Urban traffic congestion remains a pressing challenge in Erbil, particularly at signalized intersections where delays contribute to fuel consumption, emissions, and commuter frustration. This study presents a calibrated microsimulation model using PTV VISSIM to replicate field-measured control delays at a key intersection in Erbil. Field data were collected through video-based observations and analyzed to establish baseline performance. The simulation was calibrated using manual adjustments to driver behavior and signal timing parameters, constrained by the student version of the software. The model's accuracy was evaluated through statistical comparison with field data. Results showed a strong correlation (R=0.938) and a high coefficient of determination (R2=0.879), indicating that nearly 88% of the variation in simulated delay could be explained by observed conditions. Error metrics further supported the model's reliability, with a root mean square error (RMSE) of 7.31 seconds per vehicle, a mean absolute error (MAE) of 5.92 seconds, and GEH statistics consistently below 2, well within accepted thresholds for traffic modeling. While the study was limited to a single intersection due to software constraints, the findings offer practical insights for traffic engineers and policymakers. Recommendations include adopting adaptive signal control systems and integrating intelligent transportation technologies to improve intersection performance. Future research should expand the model to multiple intersections, incorporate real-time data, and explore environmental impacts. This study provides a localized, data-driven foundation for improving urban mobility in Erbil through simulation-based planning.
Abstract
In this study, turbulent flow and heat transfer in a two-dimensional channel equipped with adiabatic circular turbulators were investigated both experimentally and numerically for Reynolds numbers of 2000, 3000, 4000, and 5000. Three turbulator configurations were considered, involving one, two, and three identical turbulators, each with a diameter of $D=3$ mm and a uniform spacing of $SL=30$ mm, positioned at the channel centerline. The governing continuity, momentum, and energy equations were discretized using the finite volume method and solved iteratively using the SIMPLE algorithm. Turbulence effects were modeled using the low-Reynolds-number k-ε turbulence model. The influence of Reynolds number and turbulator count on the friction factor, average Nusselt number, entropy generation, and hydrothermal performance factor was analyzed. Results revealed that increasing the number of turbulators significantly enhances heat transfer and alters flow behavior. Both the average Nusselt number, friction factor, and entropy generation increased with turbulator number. The configuration with three turbulators demonstrated the highest hydrothermal performance, achieving a maximum performance factor of approximately 1.58 at $Re=2000$. The numerical results showed good agreement with experimental data, which also employed varying numbers of circular turbulators.
Abstract
This paper deals with the behaviour of waste pozzolanic materials, such as fly ash (FA), ground granulated blast furnace slag (GGBS), rice husk ash (RHA) and burnt brick powder (BBP)-based geopolymer concrete (GPC) under a repeated freezing and thawing cycles. The study focuses on the impact of curing regimes (24 h, 48 h, 7 d and 28 d) and exposure to 25 and 35 F-T cycles on the mechanical and durability characteristics of GPC. In recent literature, analytical and numerical work has shown that micro-crack evolution and interconnected pores dictate the degradation of strength under cyclic freezing but limited experimental data are available for waste-based GPC systems. The concretes were mixed into specimen and cured at $60^{\circ}\text{C}$ in an oven for 24 h and tested according to standard F-T testing (ASTM C666). It was found that the loss in strength up to 35 cycles did not go beyond 18 %, and residual compressive strength was higher than 80% of original one, passing durability criteria according to ASTM C666 or EN 12390-9. The relationship between the strengths in compression and tensile strength, both of F-T aged and natural samples, were roughly linear ( $R^{2}\approx0.85).$ Deeper potassium hydroxide activation and the enrichment of RHA and BBP in the AC enhanced the porosity while decreasing the mass yields, as compared with previous results. These findings demonstrate the potential uses of waste-based geopolymer concretes as environmentally friendly and frost-resistant substitutes for ordinary Portland cement in construction in sub-arctic environment.
Abstract
This paper investigates ultimate strength of lightweight concrete specimens: cubes, cylinders, and prisms wrapped by different layers CFRP respect to several curing periods. The specimens were prepared and tested under compressive and flexural loading at the ages of 7 days and 28 days with varying confinement levels (from unconfined; 0L to double-layer of CFRP, i.e., 2L). The results showed that all three factors: confinement level, specimen geometry and curing age had a significant effect on both compressive strength as well as flexural strength. Indigenous soft soil was wrapped with various CFRP wraps to study the change in failure mode from brittle to ductile with an increase in confinement and two-layer WR-CFRPs exhibited the maximum gains in compressive and flexure-up to 48% compressive, 380% of flexural strength when compared with unconfined specimens. Cylindrical samples prove always more pronounced strengthening effect than cubes, probably because of having a more even stress field and less influence to the corner effects. Besides, the confinement effect became more significant when specimens were left to cure for 28 days, highlighting initiation of concrete maturity requirement for best CFRP development. The findings indicated that early-age confinement (7-day, 2L) achieved strength equal or superior to shear-critical fully cured unconfined specimens, and confirmed the potential of CFRP in emergency repair and retrofitting. However, the ultimate strengths were the best when using both multi-layer CFRP confinement and full curing. These results highlight the synergistic relationship between geometry optimization, curing regimen and advanced fiber reinforcements in enhancing the structural response of lightweight concrete structure.
Abstract
The Bubble Deck slab is an innovative construction technique that incorporates spherical plastic voids inside concrete slabs to diminish self-weight while preserving structural integrity. This technology reduces the amount of material used by a significant amount by carefully replacing non-structural concrete with voids, which results in cost savings and improved sustainability. The production of bubble deck slabs, their design principles, benefits, drawbacks, and new developments in their use are all covered in this review study. Particular emphasis is placed on their role in modern construction, highlighting their environmental benefits, ease of installation, and structural performance compared to conventional solid slabs. Additionally, the study also highlights critical research areas, including the interaction between voids and reinforcement, the slab's behavior under static and dynamic loading conditions, and its contribution to sustainable building practices. Bubble Deck slabs help make concrete production more sustainable by minimizing the total carbon impact, improving load distribution, and decreasing construction waste. Even with these limitations, recent progress in material science and computational modeling has strengthened their potential as a sustainable and efficient substitute for standard reinforced concrete slabs. The use of Bubble Deck technology is an important advancement in the direction of structural systems that are more efficient in their use of resources and that perform better, as construction practices continue to develop toward more environmentally friendly solutions.
Abstract
Heat transfer through porous media has gained considerable interest in recent years due to its ability to enhance the thermal performance in various engineering applications. There are two key advantages of using porous materials. First, the effective heat dissipation surface area is larger than that of traditional solid fins, which intensifies convective heat transfer. Second, the irregular motion of fluid around the internal porous structure improves mixing, promoting greater thermal uniformity by breaking the boundary layer and generating vortices, while in contrast, there is a drop in the pressure of the working fluid. This review provides a structured overview of the developments in heat transfer within porous media, focusing on two categories of working fluids: conventional fluids and nanofluids. Each category is further classified according to the flow regime involved: natural, forced and mixed convection. For conventional fluids, porous structures demonstrate considerable improvements in Nusselt number and thermal efficiency in compact heat exchangers and flow channels. For nanofluids, enhanced thermal conductivity and the possibility of coupling with magnetic fields (MHD) show promising results, especially under forced and mixed convection conditions. The findings from this review reveal that while both conventional and nanofluid systems benefit from the use of porous media, nanofluids exhibit superior heat transfer capabilities when properly optimized. Additionally, the effectiveness of porous media strongly depends on geometric properties, porosity, flow regime, and thermal boundary conditions. This paper offers a comparative understanding of these systems and identifies potential directions for future research in advanced thermal system design.
Abstract
This review article discussed power amplifiers in modern wireless transmission systems, clarifying the determinants and restrictions of the create of power amplifiers in 5G and beyond transmission systems. The important topics of power amplifier design were discussed, which included solid-state techniques contributing to building the basic building block of the amplifier, furthermore to techniques for building the electronic circuit topology, while clarifying the importance of techniques for improving efficiency and linearity. This paper contributed to highlighting optimization and manufacturing techniques, focusing on the determinants and advantages of each technology. And clarifying the research space for researchers with the aim of developing a power amplifier that is optimal for use in modern wireless communications systems.
Abstract
The nonstop scaling of Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) is considered a driving force in semiconductor technology, allowing higher integration densities, enhanced performance, and reduced power consumption. However, fundamental challenges arise as device dimensions shrink to the nanoscale, such as short-channel effects, threshold voltage variation, leakage currents, and gate oxide tunneling. This study critically surveys these scaling limitations and shows potential solutions, such as high-k gate dielectrics, metal gate integration, and novel device architectures. Other transistor designs, including FinFETS, Gate-All-Around (GAA) transistors, and emerging beyond-CMOS devices, are assessed for their potential to extend Moore's Law. This study also addresses advancements in materials, including two-dimensional (2D) semiconductors and carbon-based nanostructures, that offer promising substitutes to conventional silicon technology. Regardless of these innovations, significant obstacles remain in achieving fabrication, reliability, and cost-effectiveness at sub-5nm nodes. This review paper provides insights into current progress and future guide for nanoscale MOSFET development, comprehensively assessing the challenges and opportunities in next-generation transistor technology. The findings aim to guide researchers and industry professionals toward sustainable semiconductor scaling approaches.
Abstract
The paper concentrates on the latest developments in the field of deep-learning-based image deblurring and specifically, Convolutional Neural Networks (CNNs) and how they are able to be used to deblur images. It discusses the different forms of blur such as motion blur, out-of-focus blur, and mixed blur and compares these methods under the basis of blind and non-blind methods. The article sheds light on the various architecture and model design, loss functions, and performance indicators applied in image deblurring. Moreover, it draws attention to the issues that are presently observed in the sphere and gives possible path directions of the future research. The review has condensed and synthesized existing literature to provide a clear overview of the current solutions in image deblurring and offers guidance to the researchers on how to come up with the more precise, efficient, and adaptive methods of deblurring. The developments are meant to enhance the use of image restoration techniques in practical applications and this will lead to the quality and reliability of deblurring processes.
Abstract
This review presents a comprehensive study on composites with particular interest in various synthesis techniques, advanced characterizations, and wide industrial applications. The survey includes such time categories of composites as polymer matrix (PMCs), metal matrix (MMCs), ceramic matrix carbides (CMCs), and nanocomposites, and describes the mechanical behavior and the advantages of their structural performance. The paper focuses on the development of fundamental manufacturing processes such as hand lay-up, filament winding, and additive manufacturing. It also describes different techniques of characterization of the thermal, mechanical, and electrical properties of them. Interest in the use of nanocomposites is also increasing due to their high surface area and excellent performance, which could be suitable for high-temperature and light engineering applications. Moreover, this review highlights the industrial relevance of composites, which have been extensively utilized in aerospace, automobile, marine, and civil infrastructure applications. It also solves key recyclability and environmental sustainability challenges. Finally, the paper highlights transient progress in composites as a fundamental material of new generation high-performance technologies and identifies some research gaps, but possible ways for progress towards sustainable innovation.
Abstract
The basic correlation that determines the mechanical and hydraulic characteristics of unsaturated soils is the Soil Water Characteristic Curve (SWCC). Critical synthesis The present review brings forth the latest developments in SWCC modeling, measurement and application, with a more specific interest in determining the factors that question the financial forecasting properties of current simple models, especially with dynamic environmental circumstances. In our analysis, we have found that current empirical models are frequently ineffective because they lack the explicit ability to integrate the complex/coupled nature of microstructural properties (e.g., fractal geometry and nano-porosity) and compositional differences (e.g., organic matter). More so, the synthesis shows that there is a fundamental conflict in modeling, whereas the more intricate a conventional empirical model gets, the less accurate it becomes, whereas sophisticated data-driven methods such as Deep Learning are much more effective at making predictions. As a consequence, this review confirms that one of the main future research needs should be the creation of coherent constitutive models that will combine mechanistic controls (fractal theory) and advanced AI prediction. Most importantly, the implications in practice reveal that the neglect of such coupled considerations directly compromises the validity of long-term geotechnical performance forecasts, that is, in relation to slope stability and foundation resilience to moisture changes caused by climate change. The review gives the conclusion by recommending that laboratory results should be immediately validated at a field scale to bring together the gap between theory and engineering design.