AL-Rafidain Engineering Journal (AREJ)

Solar energy is a renewable resource; however, high operating temperatures reduce photovoltaic (PV)
performance. This study examines passive cooling and reflective enhancements on PV systems in Zakho, Iraq, during
winter. Experiments were conducted on February 24 and 27 using two modified PV designs. While in Scenario I, L-shaped
aluminum fins were attached to a PV module and compared with a reference panel. Scenario II combined fins with an
aluminum reflector to increase the amount of incident solar radiation. Results showed notable performance gains. In
Scenario I, power output rose by 14.2%, with peak efficiency improving from 10% (reference) to 12%. Scenario II achieved
a 17.5% increase in power, with efficiency reaching 16.5% compared to 14% for the benchmark. Temperature decreases
of 15.3°C (Scenario I) and 13°C (Scenario II) confirmed the effectiveness of passive cooling. An examination of life cycle
costs (LCC) indicated reduced energy expenditures: $0.053/kWh for the reference scenario, down to $0.048/kWh with fins,
and further lowered to $0.044/kWh with fins combined with a reflector. The payback periods have been decreased to 6.5,
5.9, and 5.5 years for reference, fins, and combined fins with reflector systems, respectively. The environmental analysis
revealed yearly CO₂ emission reductions of 4.62, 5.25, and 5.93 tCO₂/year for reference, fins, and combined fins with
reflector systems, respectively. Overall, integrating cooling fins and reflectors significantly improved PV performance,
reduced energy costs, and enhanced environmental sustainability. This approach offers a practical and low-cost strategy
to boost solar energy utilization in regions with similar climatic conditions.

The design and quality of urban streets significantly influence accessibility, determining how easily pedestrians—
particularly those with mobility challenges—can reach essential services, amenities, and social opportunities. While prior
studies have established accessibility as a key factor in promoting walking, the relative importance of specific accessibility
indicators remains unclear. There is also uncertainty about how much each of these factors actually influences people’s
decisions to walk. Improving these accessibility factors not only makes walking easier but also enhances social interactions,
as walkable streets encourage people to meet, engage, and spend time in public spaces. This study addresses the question:
What are the most important accessibility indicators of walkability that influence social interaction in mixed-use streets?
Identifying the main accessibility factors of walkability that affect social interaction in mixed-use streets is the objective of
this paper. The aim of the study is to design a walkability model that explains how accessibility influences social interactions in mixed-use streets. The study distributed 400 Likert-scale questionnaires (1=strongly disagree to 5=strongly agree).
It used SPSS (for statistical analysis) and Smart PLS (for structural equation modeling) to process and design the model.
The analysis revealed strong model fit (GoF=0.69), emphasizing that perceived accessibility of walkability plays a crucial
role in shaping social interaction. The study concluded that the indicators contributing to ease of walking such as street
configuration, obstruction-free, sidewalk levels and condition, curb ramps, crosswalks, signage at night were among the
most influential in making the street environment more encouraging for pedestrians

This experimental study investigates the thermal performance of three solar air heater (SAH) configurations: a
conventional flat plate, a V-up perforated ribs absorber plate, and a V-down perforated ribs absorber plate. The studies
were conducted in real outdoor conditions at the University of Zakho, Zakho, Iraq, on 15, 18, and 25 February 2025. Each
SAH was tested at three different air mass flow rates: 0.00882 kg/s, 0.01323 kg/s, and 0.01764 kg/s. The findings
demonstrated that the V-down SAH consistently outperformed the others in terms of daily thermal efficiency and heat gain.
At the maximum flow rate (0.01764 kg/s), the V-down configuration achieved a maximum daily thermal efficiency of 84%
and a peak useful heat transfer rate of 529 W. The V-up SAH followed with 77% efficiency and 492 W, while the flat plate
SAH reached 69% efficiency and 470 W. The enhanced performance of the V-down design is attributed to improved
turbulence and convective heat transfer induced by its downward-facing perforated ribs. These findings confirm the
effectiveness of using V-shaped perforated ribs, particularly the V-down orientation, in enhancing the thermal performance
of solar air heaters.

This study presents an experimental investigation of a perforated-air photovoltaic/thermal (PV/T) solar
collector operating under variable airflow conditions during winter in Zakho, Iraq. The system integrates a perforated
absorber plate with controlled airflow to enhance heat transfer and energy utilization. Three mass flow rates (0.055, 0.098,
and 0.154 kg/s) were tested on separate winter days and compared to a conventional PV system. The results showed that
the PV/T system significantly improved thermal efficiency, reaching up to 79.7%, while maintaining electrical efficiency
between 12.7–13%. The highest useful thermal energy output was achieved at 0.154 kg/s, driven by improved convective
heat transfer and favorable solar conditions. Despite slightly lower electrical efficiency than the PV panel, the PV/T system
provided a much higher total energy yield. Economic analysis revealed that the PV/T system achieved up to five times
higher Net Present Value (NPV) and a payback period of 1.6 years, with a lower Levelized Cost of Electricity (LCOE) of
$0.16/kWh, compared to $0.1967/kWh for the PV system. Environmentally, the hybrid system reduced CO₂ emissions by
over 68,000 kg over 25 years, approximately four times more than the PV system. The results confirm that the perforatedair PV/T system is a highly efficient and sustainable solution for cold-climate residential energy applications

Anonymous networks are designed for confidentiality, while simultaneously keeping the sender’s identity hidden
from all nodes except the designated receiver. The decryption process requires the actual receiver to try out all possible
keys stored in memory, thereby making computation very time-consuming, especially in noisy conditions where errors and
hash collisions occur. This paper proposes a probabilistic algorithm to reduce the number of keys that must be processed,
without compromising accuracy. The algorithm models the decryption process as a discrete Markov chain the Bernoulli
formula in all its facets to calculate the probability of correct key detection and thereby determine an optimal stopping
condition. Simulation results with 15 sources and an error probability of 0.15 exhibited up to a 14% reduction in the
number of key trials required compared to brute-force search, with expected higher efficiencies for larger network sizes.
This research contribution introduces a lightweight, scalable model that reduces computational cost, saves energy, and
extends node lifetime. These findings stress the importance of providing a practical means for enhancing the performance
of anonymous communication systems, especially while working under a resource-constrained environment such as the
IoT and decentralized networks.

Wireless sensor networks (WSNs) have emerged as a promising technology in modern wireless communication
systems. These networks have been widely used in real-time applications that require reliable communication along with
energy efficiency, which heightens the need for protocols that can provide both stable communication and reduced
energy consumption. In essence, traditional hierarchical protocols, such as the threshold-sensitive energy-efficient
sensor network (TEEN), have demonstrated effectiveness in lowering redundant transmissions. However, they often
suffer limitations in adaptive energy management and the optimal selection of the cluster head (CH). Motivated by this
fact, this paper proposes QGFL-TEEN. This new hybrid frame integrates reinforcement learning (RL), genetic
algorithms (GAs), and fuzzy logic (FL) with the TEEN protocol to enhance energy efficiency, stability, and network
lifespan. The obtained results have demonstrated that the proposed frame attains up to 87.55% improvement in network
lifetime and 91.14% enhancement in stability compared to the standard TEEN protocol. Moreover, the framework
maintains higher packet delivery rates and lower energy consumption across all simulation rounds, confirming its
effectiveness for scalable and resilient WSN deployments.

Confocal Microwave Imaging (CMI) has recently emerged as a promising non-invasive method for detecting
brain tumors, leveraging the dielectric difference between healthy and diseased tissues. This study evaluates the
effectiveness of two leading beamforming algorithms—Delay and Sum (DAS) and Minimum Variance Distortionless
Response (MVDR)—for confocal image reconstruction using simulated S-parameter data from CST Studio Suite v2024.
Various head models were used, including homogeneous, symmetric heterogeneous, and realistically detailed
heterogeneous (HUGO voxel) models. Both single- and multiple-tumor scenarios were explored. The MVDR algorithm
significantly outperformed DAS in terms of tumor localization and spatial resolution, particularly in complex models and
deep tissue layers, as demonstrated in our simulations. Adaptive beamforming techniques also achieved better spatial
accuracy and contrast in heterogeneous brain phantoms. These results highlight the diagnostic potential of MVDR-based
CMI systems and lay the groundwork for future advancements through the use of larger antenna arrays and the integration
of machine learning strategies to enhance imaging performance.

The extensive utilization of cement in concrete mixtures escalates the consumption of natural resources, hence
inflating costs and augmenting carbon dioxide emissions associated with cement production. Consequently, reusing waste
materials increases the availability of natural resources, helps the environment in the long run, and makes it easier to
manage landfills. This research aims to develop green mortar using various waste cementitious materials, including Waste
Glass Powder (WGP), Waste Brick Powder (WBP), and Fly Ash Powder (FAP), with a 30 percent cement replacement
rate, thereby minimizing waste and reducing CO2 emissions. Different mix proportions of green mortars were tested for
compressive and flexural strength, density, and water absorption. The job is split into two halves. Initially, cement was
replaced by 30% of each of these materials. In the second stage, cement was replaced by different proportions of these
materials, with a total replacement of 30%. The results showed that green mortar containing 30% FAP provides higher
density and strength (under compression and flexural loading). The mix with a partial cement substitute (30%) (5% WGP
+10% FAP +15% WBP) (M2) for green mortar exhibits improved density and strength (during compression and flexural)
greater than M1 (10% WGP +10% FAP+10% WBP)