Journal of University of Babylon

‎ The broad usage of nonlinear loads in 3-phase 4-wire distribution systems defines ‎significant 3rd-harmonic currents that accumulate in the neutral conductor and diminish quality ‎of power. The present study examines a hybrid model of mitigation integrating Zigzag ‎transformer connected in shunt with the load and a series passive filter installed on the utility ‎side in the neutral conductor. The novelty of the proposed approach lies in controlling the neutral ‎current path by shaping the frequency-dependent impedance, such that third-harmonic ‎components are blocked from propagating toward the utility and are instead forced to circulate ‎through the Zigzag transformer. The filter is tuned to show high impedance at the 3rd-harmonic ‎frequency, so restricting triplen harmonic propagation to the load and directing such harmonics ‎again via Zigzag transformer. Simulations in MATLAB/Simulink under unbalanced as well as ‎balanced nonlinear loading validate the substantial reduction in neutral current distortion and ‎utility-side 3rd-harmonic currents‏.‏‎ Specifically, the proposed method achieves a reduction of ‎more than 97–99% in third-harmonic current on the utility side under balanced conditions, while ‎under unbalanced loading the neutral current total harmonic distortion (THD) is reduced from ‎‎438.4% to approximately 49.95%, showing the efficiency of the proposed configuration. ‎

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

Micro component testing has become increasingly popular over the last twenty years, ‎largely due to the reduction in system and device sizes. The continuous evolution of technologies ‎such as medical and bioengineering, microelectromechanical systems, and aerospace has imposed ‎an imperative need to improve mechanical testing methods for small components. These ‎industries need intricate and complex parts, which require improving the methods of testing to ‎accommodate such small sizes. The latest review examines the current methods and techniques of ‎mechanical testing of micro components, regarding their adaptation to incredibly small ‎components. More than one hundred studies in this field were summarized and reviews the ‎recent developments in the field of micro component testing, in addition to focusing on the ‎methods and techniques used. In addition, highlighting future challenges and research paths that ‎contribute to the development of these technologies were highlighted. These insights offer ‎valuable guidelines for researchers, engineers, and technologists working in precision ‎manufacturing, such as micro-electro-mechanical systems (MEMS), electronics, semiconductors, ‎and biomedical device development. Future work can focus on destructive and non-destructive ‎testing methods, associated with computational modeling.‎

Power transmission lines hold the fort of modern electrical infrastructure, however they ‎come under continuous threat of different kinds of faults that can put grid stability at risk, ‎endangering supply continuity. Conventional protection schemes adopt fixed threshold ‎techniques which is one of the major obstacles in identifying the high impedance faults and also ‎demand heavy investment on the special hardware. The objective of this work is to develop and ‎implement a smart system for early faults detection in transmission line in an efficient and cost-‎effective manner, using lightweight deep learning methods. An experimental procedure was ‎developed based on the simulation of the environment of the power transmission system in order ‎to create a synthetic dataset which consists of multi-operational conditions and multiple fault ‎types. Electrical signals were preprocessed by a sequence of well-defined operations, including ‎normalization and Clarke transformation, to effectively reduce influences of unwanted noise and ‎bring out the most essential temporal and spatial features. To allow automatic abnormal pattern ‎recognition, a one-dimensional convolutional neural network model was trained on the generated ‎data. As the results of the experiment, it was found that the proposed model is obviously superior ‎to traditional protection methods in classification accuracy and response speed, and has better ‎stability under complex operating conditions. It also demonstrated the ability to run on less ‎expensive hardware, thereby reducing the computational burden and allowing the system to run ‎in the field as well. The study concludes that the utilization of artificial intelligence algorithms in ‎conjunction with the existing protection system is able to improve electrical grid reliability in ‎addition to acting as an a cost-effective and scalable solution for future smart grid infrastructure.‎

Modern power systems face challenges because of long-distance power transmission ‎requirements, increasing power demand, and the widespread use of renewable energy sources. ‎The research focuses on evaluating how Static Synchronous Compensator (STATCOM) systems ‎improve voltage and transient stability assessment in power transmission networks. The research ‎combines two methods which use both analytical techniques and simulation techniques to assess ‎voltage stability through two indices (VSI and L-index) and critical clearing time (CCT) ‎assessment and eigenvalue-based oscillation damping assessment. This study created ‎mathematical models for STATCOM which include DC-link voltage dynamics and reactive ‎power injection equations and they applied these models to a standard IEEE test system. The ‎simulation results show that the installation of STATCOMs leads to a 25% to 40% improvement ‎in voltage stability margin and it boosts minimum bus voltage from 0.82 p.u. to 0.95 p.u. under ‎heavy loading conditions. Moreover, it extends CCT by 20% to 30% and shortens voltage ‎recovery time by 35% to 50% and reduces low-frequency oscillation amplitudes by 40% to 60%. ‎The quantitative findings, validated through time-domain simulation and eigenvalue analysis ‎demonstrate that intelligent STATCOMs provide better results for transmission network stability ‎than traditional compensation methods.‎

This paper presents a comparative study of thermal properties of a shell and tube type ‎heat exchanger filled with an Al2O3-water nanofluid with the one filled by pure water. It was ‎decided to use Aluminum oxide (Al2O3) because it was chemically stable, commercially ‎available and found to be effective in improving thermal conductivity without extreme hydraulic ‎penalties. The experiments were carried out for a range of Reynolds numbers between [12,600 to ‎‎63,300] and at a concentration of 30g per 10L of base fluid. The effectiveness-NTU (ε-NTU) ‎approach was used for data reduction. The results indicate that the counter-flow design produced ‎a large positive effect, increasing the effectiveness by 17-19%, and a reduction in the fluid ‎temperature at the high end by about 5°C. The parallel-flow configuration enhanced the ‎performance as well, with an approximate 16% more effectiveness gain. The improvement in ‎thermal conductivity was achieved with the addition of nanoparticles; however, the increase in ‎the fluid viscosity means that extra pumping power may be necessary. In conclusion, low ‎concentration Al2O3 nanofluids are potentially useful to enhance the thermal efficiency of the ‎heat transfer processes used in industry, but hydraulic losses must be adequately reduced.‎

Due to the inherent nonlinearity and transient dynamics of modern electrical power ‎systems, a significant gap has emerged between idealized optimization models and the practical ‎reality of grid operations. To bridge this gap, this study proposes a dynamic hybrid optimization ‎protocol that synergistically combines the global exploration capabilities of metaheuristic ‎algorithms with the precise local exploitation of deterministic mathematical solvers. The ‎algorithm dynamically alternates between a stochastic search phase and a gradient-based refining ‎phase using a variance-based transition mechanism. To validate scalability and robustness, the ‎protocol is tested on both the standard IEEE 30-bus and the large-scale IEEE 118-bus test ‎systems. Unlike standalone metaheuristics, which often leave residual power imbalances (up to ‎‎1.5 MW), the proposed hybrid protocol achieves exact physical feasibility (0.0000 MW ‎mismatch) without violating equality constraints. Furthermore, statistical analysis conducted over ‎‎30 independent runs, validated by the Wilcoxon rank-sum test, demonstrates superior ‎consistency, computational efficiency, and repeatability compared to state-of-the-art baselines. ‎The protocol ensures strict adherence to voltage stability (0.95–1.05 p.u.) and thermal limits. ‎These findings confirm that hybridizing metaheuristics with deterministic solvers translates ‎theoretical optima into safe, economical, and physically executable real-world electrical dispatch ‎commands.‎

The present study is concerned with creating a comprehensive evaluation framework ‎consisting of multiple dimensions of quantitative indicators for measuring digital integration ‎levels in the context of sustainable environmental design for residential complexes. The ‎framework has been created based on the information provided about the Al-Sultan Residential ‎Complex in Al-Najaf Al-Ashraf, Iraq.‎
In response to the absence of a clear quantitative mechanism for assessing digital ‎integration in sustainable environmental design, the proposed framework suggests that the use of ‎digital technology to measure environmental indicators enhances the process of assessing ‎performance, including energy efficiency, thermal comfort, and internal environmental quality. ‎The research methodology was both analytic and evaluative and used quantitative indicators ‎across five major areas; digital connection, digital environmental monitoring, energy use ‎efficiency, environmental integration with vegetation, safety and security. All of these indicators ‎were compared against benchmarks using international standards.‎
Digital simulation, according to the obtained results, can be implemented across all areas ‎of design to achieve energy savings and improved thermal comfort, as well as to ensure adequate ‎indoor air quality through monitoring systems. On the other hand, the results revealed that there ‎was no net-zero energy performance because buildings are still utilizing traditional forms of ‎electricity; further, there is little green space even though the pedestrian network has been ‎designed properly and is up to code with the amount of native plants; and finally, the ratings for ‎safety were moderate.‎
According to the research, in order for home complexes to develop environmentally ‎sustainable practices, they need to utilize a complete planning technique that integrates growing ‎the amount of green space, utilizing renewable energy resources, and improving the quality of ‎urban areas so as to change the concept of sustainability from a descriptive one into an ability to ‎do a measurable assessment of sustainability.‎

Concrete curing plays an important part in the production of high-quality concrete. Curing ‎is the method of maintaining the proper temperature and moisture levels in concrete to keep the ‎reaction between water and cement compounds continuous. It is widely acknowledged that ‎concrete needs to be completely cured to attain its ideal properties. For different reasons, the ‎initial curing may not be provided. A significant number of studies have found that delayed ‎curing negatively affects the hardened concrete’s properties. Controlling the moisture content of ‎concrete can increase strength , reduce permeability, and increase durability, especially when ‎exposed to harsh environments. It also improves compressive strength due to the reduction of the ‎void size and ratio. This review deals with the consequences of initial curing delay time, strength ‎grade, mix proportions, and the curing regime on the physical and mechanical properties of ‎concrete. In addition, the variation of some properties of concrete such as strength and durability, ‎according to the curing type and duration, is reported. This topic is very important to site ‎engineers. The factors that affect the results of the compressive strength and durability of ‎concrete have to be taken into consideration; thus, it is advisable to cover it more widely.‎

One of the biggest problems facing growth in many developing countries is slum housing. ‎The Diyala governorate is afflicted by unregulated expansion, stemming from informal housing ‎clusters caused by demographic, social, and economic factors that adversely impact the ‎organization of land use, particularly residential applications. This paper aims to identify and ‎analyze the factors influencing the growth of slum housing in terms of economic, social, and legal ‎aspects, as well as evaluate proposals to address the problem of slum housing. A questionnaire ‎was used to achieve the goal of this paper. The results showed that the most important factors ‎that increase the growth of slum housing in Diyala Governorate in terms of the economic and ‎social axis are the cost of purchasing housing compared to the average per capita income and the ‎cost of equipment and machinery, while in terms of the legal axis the most important factors are ‎the weakness of the state law, the increase in population, and the housing deficit. The results ‎concluded that some of the slums require low-cost housing complexes, while others require ‎infrastructure improvements.‎

The electrophoretic deposition (EPD) technique was used to prepare seven-layered ‎functionally graded hydroxyapatite/titanium dioxide (HAp/TiO₂) coatings on Ti–6Al–4V alloy ‎for biomedical implant applications. The coating structure was designed with a compositional ‎gradient from pure TiO₂ near the substrate to pure HAp on the outer surface, so as to combine the ‎corrosion resistance of TiO₂ with the bioactivity of HAp. The coated samples were heat-treated ‎at 950°C for one hour under an argon atmosphere to improve the coating stability and phase ‎formation after deposition.‎
The structural characteristics of the coatings were evaluated by X-ray diffraction (XRD). ‎The obtained results confirmed the presence of hydroxyapatite as well as anatase and rutile ‎phases of titanium dioxide. Furthermore, other calcium phosphate phases were observed due to ‎the partial decomposition of hydroxyapatite during the sintering process. The corrosion behavior ‎was evaluated by potentiodynamic polarization tests in Ringer’s solution, where the coated ‎samples showed better corrosion resistance than the uncoated Ti–6Al–4V alloy. with corrosion ‎characteristics gradually increasing from S1 to S7. S7 coating showed the highest noble corrosion ‎potential (Ecorr = −0.23 V), lowest corrosion current density (Icorr = 2.02 µA/cm2) and lowest ‎corrosion rate (CR = 0.018 mpy).‎‏ ‏The antibacterial activity against *Escherichia coli* was also ‎evaluated by the inhibition zone method. The produced coatings showed good antibacterial ‎activity and reduced the development of E. coli bacteria.‎‏ ‏The results indicate that functionally ‎graded HAp/TiO2 coatings can greatly improve the surface properties of Ti-6Al-4V alloy ‎‏ ‏concurrently boosting corrosion resistance and antibacterial performance‏ ‏and have great potential ‎in biomedical implant applications.‎

In practice, in high-rise buildings, especially in reinforced concrete deep beams bearing ‎high axial loads, openings may be located in the zone of maximum shear force and zero bending ‎moment (shear control), and this may be a serious problem if the shear strength of these beams is ‎not predicted. Therefore, this study aimed to investigate the ultimate shear strength in this case ‎‎(shear control) experimentally and compare the results with analytical equations to make it easier ‎for those working in this field to use these equations when needed. In this research, the ‎experimental deep beam specimens were divided into two groups. The first group consists of ‎three reinforced concrete deep beams as normal concrete beams; the first is solid, and the second ‎and third have square openings of 200 mm and 300 mm, respectively. The second group has the ‎same arrangement as the first group, with the addition of 0.75% steel fibers to the concrete mix ‎as fibrous concrete deep beams.‎‏ ‏The experimental results indicated that the presence of square ‎openings with sharp corners leads to a reduction in the ultimate shear strength of the beams due ‎to the interruption of the load transfer path. Steel fibers improved the performance of the beams, ‎increased the cracking load, and delayed the failure load.‎‏ ‏The Kong and Sharp equation was ‎used for reinforced concrete deep beams (solid and with opening),‎‏ ‏the ratio of experimental to ‎analytical ultimate shear strength for the fibrous reinforced concrete deep beams was 0.998 for ‎the solid beam, 1.162 and 1.585 for beams with 200 mm and 300 mm square openings, ‎respectively. For the normal reinforced concrete deep beams, the ratios were 0.871 for the solid ‎beam, 1.167 and 1.245 for beams with 200 mm and 300 mm square openings, respectively. In ‎general, the analytical results were close agreement with the experimental results. Therefore, these ‎equations can be reliably used to predict the ultimate shear strength of normal and fibrous ‎reinforced concrete deep beams with openings located in the region of maximum shear forces ‎and zero bending moments (shear control).‎

The evolving need for environmentally friendly construction materials has led to the ‎creation of lightweight self-compacting concrete (LWSCC). This overview examines the effect ‎of lightweight coarse aggregate (LWCA) type on fresh and hardened properties of LWSCC, ‎specifically evaluating the use of local lightweight Attapulgite aggregate (ATG) and comparing it ‎with the conventional lightweight coarse aggregate, lightweight expanded clay aggregate ‎‎(LECA). The study produced two LWSCC mixes with the same amount of binder and tested ‎them using common methods for fresh and hardened properties, including slump flow, V-funnel, ‎L-box, compressive strength, splitting tensile strength, flexural strength, modulus of elasticity, ‎and impact resistance. The results confirmed that each ATG- and LECA-based mix met the ‎EFNARC requirements for fresh property and ACI limits for structural lightweight concrete ‎‎(SLWC), which indicate that they can flow without vibrations and get compressive strength ‎higher than 17 MPa. On the other hand, the flowability of the ATG mixtures was slightly lower ‎because they absorbed extra water and had particles with angler edge, rough texture, and ‎production method. Therefore, fresh properties have shown some increase when compared with ‎LECA. LWSCCs primarily based on ATG had approximately 11% additional compressive ‎strength and 21% better elasticity parameters than LECA mixtures. Furthermore, the overall ‎performance in tensile, bending, and impact improved. The results show that ATG can be a viable ‎alternative to conventional lightweight aggregates. This will help the environment and make the ‎system perform better.‎

The paper gives a systematic literature review about the use of industrial by-products, ‎fly ‎ash, ground granulated blast furnace slag (GGBFS), silica fume, and waste glass powder ‎as ‎supplementary cementitious materials (SCMs) in concrete. Which identifies, screens, and ‎critically ‎synthesizes over 50 peer-reviewed studies published between 2000 and 2025. The paper ‎provides a ‎thorough analysis and discussion of the chemical and physical properties, pozzolanic ‎and hydraulic ‎activities and effects on fresh and hardened concrete, workability, setting time, ‎strength ‎development, and long-term durability. Moreover, it discusses the environmental and ‎financial ‎effects, including CO₂ emissions, landfill waste diversion, cost efficiency, and ‎conservation of ‎resources. The findings indicate that fly ash (15-30% replacement) strengthens in ‎the long term and ‎provides sulfate resistance; silica fume (5-10%) strengthens early age strength ‎and impermeability; ‎GGBFS (30-50%) makes it stronger in adverse environments; and waste ‎glass powder reduces ‎alkali-silica reactivity and encourages waste application. Altogether, the ‎analyzed literature suggests ‎that SCMs have the potential to reduce CO₂ emissions from cement ‎production by up to 50 percent ‎and contribute to a circular economy.‎

The present paper aims to undertake a comparison between the corrosion inhibition effects of asphalt and ‎tar paints used on the surface of steel samples subjected to sodium chloride environments of different ‎concentrations (0.5 M and 1.0 M). This was done by first coating the steel samples before subjecting them ‎to sodium chloride environments for a period of 17 days. Measurements of the weight loss of samples ‎after every 72 hours were made in order to estimate the corrosion rates. The gravimetric technique was ‎employed in determining the corrosion rate in accordance with ASTM G31-21 standards. Other tests such ‎as TDS and SEM were done to study salt concentration levels and microstructure alterations of surfaces. ‎It is noted that there was a steady reduction in both salt concentration and corrosion rates as a result of ‎iron oxide and hydroxides coating on the surface. Asphalt coatings showed a better level of protection ‎against corrosion than tar coatings and untreated samples. The values of the corrosion rates were equal to ‎‎0.19 mm/year in 0.5 M NaCl solution and 0.36 mm/year in 1.0 M NaCl solution, while in the case of tar ‎coatings they were equal to 0.28 and 0.52 mm/year correspondingly. SEM micrographs revealed that ‎asphalt coating was dense, homogeneous, and tightly adhering to the surface with few defects, while tar ‎coating was characterized by microcracks and porosities.‎

The paper explores systematic optimization of hybrid epoxy nanocomposite coatings that ‎are reinforced with functionalized zinc oxide nanoparticles and graphene oxide sheets to develop ‎maximum corrosion resistance on cold-rolled steel. In response to the objectives, a three-factor, ‎three-level Box-Behnken Design under Response Surface Methodology was used to determine ‎how the functionalized zinc oxide concentration, graphene oxide concentration, and curing ‎temperature affect the coating resistance as measured by Electrochemical Impedance ‎Spectroscopy. Microstructural characterization using Field Emission Scanning Electron ‎Microscopy and X-ray Diffraction proved the successful silane-functionalization of zinc oxide ‎and the high amount of graphene oxide exfoliation that combined to create a complex tortuous ‎path of corrosive elements. Statistical analysis showed that the quadratic model was very ‎significant with a value of which showed that the two variables of nanofillers and curing process ‎interacted synergistically. Optimization analysis revealed that the optimal formulation factors ‎were 2.25 weight percentage functionalized zinc oxide and 0.85 weight percentage graphene ‎oxide at a curing temperature of 95°C , yielding a maximized value of coating resistance of . ‎This is an order of magnitude better than neat epoxy, which confirms the effectiveness of hybrid ‎nanomaterials and statistical modeling when it comes to creating better industrial protective ‎coats.‎