Eng

18 pages, 2852 KiB

Open AccessArticle

Assessment of the Influence of Formation Conditions of Embankments and Spoil Heaps on Their Stability When Dumped on Clay-Salt Slurries

by Maxim Karasev and Tatsiana Astapenka

Eng 2025, 6(1), 2; https://doi.org/10.3390/eng6010002 - 26 Dec 2024

Abstract

The formation of geotechnical structures on foundations composed of low-strength soils is associated with a number of risks and difficulties. Soils such as clay-salt slurries are characterized by low bearing capacity and a tendency to deform under load. In this study, a numerical [...] Read more.

The formation of geotechnical structures on foundations composed of low-strength soils is associated with a number of risks and difficulties. Soils such as clay-salt slurries are characterized by low bearing capacity and a tendency to deform under load. In this study, a numerical simulation of the stability analysis of an embankment constructed on low-strength soils consisting of clay-salt slurries is carried out, and the study of the dependence of the stability and behavior of the embankment on the configuration of this foundation, without taking into account the embedment of rocks and with introduction of rocks into the geotechnical system, is considered. The results prove that the sloping configuration of low-strength soils greatly complicates the stability of the embankment. It is noted that the stability factor is significantly reduced under the influence of loads on low-strength soil, particularly when the geotechnical system has a configuration with slope angles of 5° and 10°, and, in addition, when rocks are embedded in low-strength soil if the underlying soil layer is a weak foundation. In view of this, the assessment of embankment stability on clay-salt slurries requires careful analysis due to a number of specific characteristics of these soils that create complex geotechnical conditions. Full article

(This article belongs to the Section Chemical, Civil and Environmental Engineering)

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14 pages, 891 KiB

Open AccessCommunication

Evaluation of Expanded Clay and Tuff as Lightweight Agents in Concrete Stabilized with Nopal Mucilage and Aloe Vera

by Daniel Mendoza-Goden, Rocio Rafaela Gallegos-Villela, Pedro Flores-Becerra, Josue Francisco Perez-Sanchez, Edgardo Jonathan Suarez-Dominguez and Arturo Palacio-Perez

Eng 2025, 6(1), 1; https://doi.org/10.3390/eng6010001 - 26 Dec 2024

Abstract

Objectives: This study aims to evaluate the potential of lightweight concrete mixtures incorporating sustainable materials, such as nopal mucilage and aloe vera, to enhance thermal and structural performance while promoting eco-friendly construction practices. The objective is to analyze their effects on physical, mechanical, [...] Read more.

Objectives: This study aims to evaluate the potential of lightweight concrete mixtures incorporating sustainable materials, such as nopal mucilage and aloe vera, to enhance thermal and structural performance while promoting eco-friendly construction practices. The objective is to analyze their effects on physical, mechanical, and thermal properties to optimize mixture design. Methods/Analysis: Six lightweight concrete mixtures were prepared using varying dosages of tuff, expanded clay, nopal mucilage, and aloe vera as lightweight and stabilizing agents. To assess their performance, a series of physical tests (bulk density, water absorption, and slump), mechanical tests (compressive strength), and thermal characterizations (conductivity, heat capacity, and resistivity) were conducted. Fractal analysis was employed to evaluate the structural complexity of the mixtures. Findings: The results revealed significant differences based on the materials used. Mixtures with aloe vera exhibited extreme water absorption (up to 11.472%) and varying consistency, from fluid (“spreads”) with tuff to workable with expanded clay. When combined with expanded clay, Nopal mucilage-based mixtures showed lower workability but higher compressive strengths (up to 11.447 MPa). Expanded clay increased bulk density and enhanced thermal efficiency, with mixtures incorporating aloe vera or nopal mucilage demonstrating high heat retention and structural complexity. The compressive strengths ranged from 7.343 MPa (aloe vera-tuff) to 12.207 MPa (water-tuff), highlighting the impact of stabilizing agents on mechanical performance. Novelty or Improvement: This study introduces a novel evaluation of lightweight concrete mixtures using nopal mucilage and aloe vera, focusing on their synergistic effects with lightweight aggregates such as tuff and expanded clay. The findings provide valuable insights into optimizing eco-friendly concrete mixtures with improved thermal retention, workability, and mechanical properties, offering a sustainable alternative for modern construction. Full article

(This article belongs to the Section Chemical, Civil and Environmental Engineering)

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11 pages, 7192 KiB

Open AccessArticle

Upcycling of Eggshell Waste into Calcium Phosphates for Use in Sustainable Biomedical Engineering Applications

by Nikolaos Pagonis, Dimitrios Flegkas, Aikaterini Itziou, Konstantinos Kountouras, Adam Stimoniaris, Petros Samaras and Vayos Karayannis

Eng 2024, 5(4), 3540-3550; https://doi.org/10.3390/eng5040184 - 20 Dec 2024

Abstract

Eggshells are an inorganic waste, and their accumulation rate is increasing globally, complicating waste management. However, the European Union defines eggshells as low-risk material that can be recycled and reused safely in other applications. Their chemical composition renders them an attractive precursor of [...] Read more.

Eggshells are an inorganic waste, and their accumulation rate is increasing globally, complicating waste management. However, the European Union defines eggshells as low-risk material that can be recycled and reused safely in other applications. Their chemical composition renders them an attractive precursor of calcium phosphate materials (CaPs). Because of their remarkable biocompatibility and capacity for natural degradation, CaPs are frequently employed in biomedical engineering applications. In this research, the wet precipitation method was employed for fabricating CaP powder. Initially, the eggshells were processed into CaCO₃ powder and then reacted with HCl to obtain CaCl₂ (aq). This reacted with Na₂HPO₄ to obtain a precipitate that was filtered and dried. The precipitate in powder form underwent X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analysis to evaluate its microstructure, and elemental and phase composition. The results indicated that the recovered powder was brushite. Full article

(This article belongs to the Special Issue Green Engineering for Sustainable Development 2024)

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23 pages, 3263 KiB

Open AccessArticle

Application of Diverse Testing to Improve Integrated Circuit Test Yield and Quality

by Chung-Huang Yeh, Shou-Rong Chen and Kan-Hsiang Liao

Eng 2024, 5(4), 3517-3539; https://doi.org/10.3390/eng5040183 - 20 Dec 2024

Abstract

This paper utilizes the digital integrated circuit testing model to compute the test yield curve of future wafers and explore the influence of test guardband (TGB) on quality and yield. With the passage of three years since the COVID-19 pandemic disrupted semiconductor production [...] Read more.

This paper utilizes the digital integrated circuit testing model to compute the test yield curve of future wafers and explore the influence of test guardband (TGB) on quality and yield. With the passage of three years since the COVID-19 pandemic disrupted semiconductor production lines, the semiconductor manufacturing industry still faces chip shortages. Although initiatives such as the CHIPS and Science Act in the United States have helped stabilize chip supply chains, manufacturers still face inventory shortages and delayed deliveries. Moreover, the backwardness and inaccuracy of semiconductor test equipment have led to a decline in both test yield and wafer quality, resulting in reduced shipments. Therefore, to mitigate yield losses and enhance the test yield and shipment volume of semiconductor products, this paper proposes a diverse test method (DTM) to improve test outcomes through the alteration of the testing strategy and TGB adjustment. Furthermore, according to the wafer estimation table published in the IEEE International Roadmap for Devices and Systems (2023), the proposed DTM can effectively enhance the test yield of wafers and improve the testing capabilities of ATE testers (automatic test equipment). Consequently, suppliers can stabilize the chip supply chain and enhance their companies’ profits and reputation by improving chip test yield. Full article

(This article belongs to the Section Electrical and Electronic Engineering)

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29 pages, 34806 KiB

Open AccessArticle

An Adaptive YOLO11 Framework for the Localisation, Tracking, and Imaging of Small Aerial Targets Using a Pan–Tilt–Zoom Camera Network

by Ming Him Lui, Haixu Liu, Zhuochen Tang, Hang Yuan, David Williams, Dongjin Lee, K. C. Wong and Zihao Wang

Eng 2024, 5(4), 3488-3516; https://doi.org/10.3390/eng5040182 - 20 Dec 2024

Abstract

This article presents a cost-effective camera network system that employs neural network-based object detection and stereo vision to assist a pan–tilt–zoom camera in imaging fast, erratically moving small aerial targets. Compared to traditional radar systems, this approach offers advantages in supporting real-time target [...] Read more.

This article presents a cost-effective camera network system that employs neural network-based object detection and stereo vision to assist a pan–tilt–zoom camera in imaging fast, erratically moving small aerial targets. Compared to traditional radar systems, this approach offers advantages in supporting real-time target differentiation and ease of deployment. Based on the principle of knowledge distillation, a novel data augmentation method is proposed to coordinate the latest open-source pre-trained large models in semantic segmentation, text generation, and image generation tasks to train a BicycleGAN for image enhancement. The resulting dataset is tested on various model structures and backbone sizes of two mainstream object detection frameworks, Ultralytics’ YOLO and MMDetection. Additionally, the algorithm implements and compares two popular object trackers, Bot-SORT and ByteTrack. The experimental proof-of-concept deploys the YOLOv8n model, which achieves an average precision of 82.2% and an inference time of 0.6 ms. Alternatively, the YOLO11x model maximises average precision at 86.7% while maintaining an inference time of 9.3 ms without bottlenecking subsequent processes. Stereo vision achieves accuracy within a median error of 90 mm following a drone flying over 1 m/s in an 8 m

\times

4 m area of interest. Stable single-object tracking with the PTZ camera is successful at 15 fps with an accuracy of 92.58%. Full article

(This article belongs to the Special Issue Feature Papers in Eng 2024)

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21 pages, 6784 KiB

Open AccessArticle

The Consequences of a Lack of Basic Sanitation in the Municipality of Maricá (Rio de Janeiro, Brazil) Resulting in Low Concentrations of Metals but Dissemination of Endocrine Disruptors Through Local Environments: Subsidies for Local Environmental Management

by Moisés L. Gil, Estefan M. da Fonseca, Bruno S. Pierri, Jéssica de F. Delgado, Leonardo da S. Lima, Danieli L. da Cunha, Thulio R. Corrêa, Charles V. Neves and Daniele M. Bila

Eng 2024, 5(4), 3467-3487; https://doi.org/10.3390/eng5040181 - 19 Dec 2024

Abstract

Endocrine-disrupting compounds (EDCs) are emerging pollutants that can potentially accumulate in aquatic ecosystems at significant levels, with the potential to impact the health of both animals and humans. Many scientists have correlated human exposure to high concentrations of EDCs with critical physiological impacts, [...] Read more.

Endocrine-disrupting compounds (EDCs) are emerging pollutants that can potentially accumulate in aquatic ecosystems at significant levels, with the potential to impact the health of both animals and humans. Many scientists have correlated human exposure to high concentrations of EDCs with critical physiological impacts, including infertility, thyroid imbalance, early sexual development, endometriosis, diabetes, and obesity. Several substances, such as heavy metals, belong to this family, ranging from natural to synthetic compounds, including pesticides, pharmaceuticals, and plastic-derived compounds. Domestic sewage represents a significant source of EDCs in the surrounding aquatic ecosystems. To this day, most rural and urban domestic wastewater in the municipality of Maricá is directly discharged into local aquatic environments without any treatment. The present study aimed to assess the potential contamination of the riverine and lagoonal environment in the municipality of Maricá. Water and sediment samples were collected seasonally at 18 sites along the Maricá watershed and the main lagoon, into which most of the watershed’s contributors flow. Water physico-chemical parameters (pH, reduction–oxidation potential—Eh, dissolved oxygen levels, salinity, turbidity, temperature, and fecal coliforms) were analyzed to characterize the urban influence on the aquatic environment. Sediment samples were also analyzed for grain size, total organic carbon percentage, potential bioavailable fraction of trace metals (Cd, Pb, Cu, Cr, Hg, Ni, Zn), and metalloid As. Finally, the sediment toxicity was assessed using yeast estrogen screen (YES) assays. The results obtained already demonstrate the presence of estrogenic effects and raise concerns about water quality. The current study indicates that, despite the absence of agricultural and industrial activities in the city of Maricá, EDCs are already present and have the potential to impact the local ecosystem, posing potential risks to human health. Full article

(This article belongs to the Special Issue Green Engineering for Sustainable Development 2024)

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16 pages, 1145 KiB

Open AccessArticle

Thermodynamic and Kinetic Analysis of a CO₂ Hydrogenation Pilot Scale Reactor for Efficient Methanol Production

by Antonis Peppas, Chrysa Politi, Konstantinos Charalampopoulos, Vasiliki Kontou and Sotirios Karellas

Eng 2024, 5(4), 3451-3466; https://doi.org/10.3390/eng5040180 - 18 Dec 2024

Abstract

Decarbonization of hard-to-abate industrial sectors, namely the extractive industries, has become an imperative, and thus, processes such as carbon capture and utilization (CCU) have been explored thoroughly and seem to be a promising solution. Carbon dioxide (CO₂) catalytic hydrogenation employing green [...] Read more.

Decarbonization of hard-to-abate industrial sectors, namely the extractive industries, has become an imperative, and thus, processes such as carbon capture and utilization (CCU) have been explored thoroughly and seem to be a promising solution. Carbon dioxide (CO₂) catalytic hydrogenation employing green hydrogen (H₂) to produce synthetic methanol (MeOH) aims to utilize industrial-captured carbon. A thermodynamic and kinetic analysis of a pilot scale methanol synthesis reactor was conducted by modeling the process using Aspen Plus V12 software. The methanol synthesis model consists mainly of a multi-tubular packed-bed reactor with a thermal oil heat recovery system, a product separator, and an internal recycle loop for optimal efficiency. The reactor has a 5 kg h⁻¹ methanol production capacity, and its heat recovery system achieves an overall heat reduction of 64.1% and can retrieve 1.293 kWh per kg of methanol produced. The overall carbon conversion achieved is 80.6%. Valuable information concerning the design and profile of the reactor is provided in this study. Full article

(This article belongs to the Special Issue Green Engineering for Sustainable Development 2024)

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12 pages, 6701 KiB

Open AccessArticle

Synthesis of Waste-Derived Geopolymer–Zeolite Composite with Enhanced CO₂ Adsorption Capacity

by Andresa Rodrigues da Silveira, Alisson Lopes Freire, Fábio Elyseu, Regina de Fátima Peralta Muniz Moreira, Michael Peterson, Aidan Doyle, Sibele Berenice Castella Pergherd, Dachamir Hotza and Agenor De Noni, Jr.

Eng 2024, 5(4), 3439-3450; https://doi.org/10.3390/eng5040179 - 18 Dec 2024

Abstract

Carbon dioxide levels in the atmosphere are related to global warming and climate change. Materials to be used for CO₂ capture are an important factor in assisting humanity in overcoming this challenge. The goals of this study are to look into the [...] Read more.

Carbon dioxide levels in the atmosphere are related to global warming and climate change. Materials to be used for CO₂ capture are an important factor in assisting humanity in overcoming this challenge. The goals of this study are to look into the synthesis of adsorbents from red mud (RM), fly ash (FA), and metakaolin (MK). The initial composition was chosen to induce in situ crystallization of zeolites dispersed together with a geopolymer matrix. Two aging steps were used, which combined temperature (25; 95 °C) and atmosphere (air; water). The MK + FA system crystallized zeolite sites dispersed throughout the geopolymer matrix. These crystals were identified as faujasite-Na. They were responsible for the surface area ranging from 23.2 to 238.4 m².g⁻¹, and CO₂ adsorption from 0.83 to 2.32 mmol.g⁻¹ at 35 °C and 1 atm. The best results were obtained by first aging at 95 °C for 120 h, followed by water aging at 25 °C for 120 h. Full article

(This article belongs to the Special Issue Emerging Trends in Materials Engineering for Clean Energy Applications)

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12 pages, 2056 KiB

Open AccessArticle

Investigation of the Hottel–Whillier–Bliss Model Applied for an Evacuated Tube Solar Collector

by Márton Rátkai, Gábor Géczi and László Székely

Eng 2024, 5(4), 3427-3438; https://doi.org/10.3390/eng5040178 - 18 Dec 2024

Abstract

The goal of this research is to examine the applicability of the Hottel–Whillier–Bliss model, developed for flat-plate collectors, to evacuated tube solar collectors. During this study, the model is applied to an evacuated tube collector, and then the identification and validation of the [...] Read more.

The goal of this research is to examine the applicability of the Hottel–Whillier–Bliss model, developed for flat-plate collectors, to evacuated tube solar collectors. During this study, the model is applied to an evacuated tube collector, and then the identification and validation of the model are made with the help of measurements performed on the collector. This research also includes the application, identification and validation of the energy balance model for the investigated solar collector. This model works for both flat-plate and evacuated tube collectors. The results obtained with the two different models are then compared. By comparing the modelled results with the measured values, the accuracy and applicability of the models can be determined. Based on the results, the Hottel–Whillier–Bliss model works excellently with evacuated tube solar collectors for predicting the outlet temperature of the medium from the solar collector. It is important to note that the identification gives negative heat transfer parameter values. According to the validation, the average absolute error is 0.8 °C, and the average relative error is 1%. For the energy balance model, these values are 0.87 °C and 1.1% respectively, indicating that the accuracy of the Hottel–Whillier–Bliss model is very similar, and even slightly higher. Additionally, the research provides further proof of the applicability of the energy balance model to evacuated tube collectors. Full article

(This article belongs to the Special Issue Feature Papers in Eng 2024)

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30 pages, 3647 KiB

Open AccessReview

A Comprehensive Review of Smartphone and Other Device-Based Techniques for Road Surface Monitoring

by Saif Alqaydi, Waleed Zeiada, Ahmed El Wakil, Ali Juma Alnaqbi and Abdelhalim Azam

Eng 2024, 5(4), 3397-3426; https://doi.org/10.3390/eng5040177 - 16 Dec 2024

Abstract

Deteriorating road infrastructure is a global concern, especially in low-income countries where financial and technological constraints hinder effective monitoring and maintenance. Traditional methods, like inertial profilers, are expensive and complex, making them unsuitable for large-scale use. This paper explores the integration of cost-effective, [...] Read more.

Deteriorating road infrastructure is a global concern, especially in low-income countries where financial and technological constraints hinder effective monitoring and maintenance. Traditional methods, like inertial profilers, are expensive and complex, making them unsuitable for large-scale use. This paper explores the integration of cost-effective, scalable smartphone technologies for road surface monitoring. Smartphone sensors, such as accelerometers and gyroscopes, combined with data preprocessing techniques like filtering and reorientation, improve the quality of collected data. Machine learning algorithms, particularly CNNs, are utilized to classify road anomalies, enhancing detection accuracy and system efficiency. The results demonstrate that smartphone-based systems, paired with advanced data processing and machine learning, significantly reduce the cost and complexity of traditional road surveys. Future work could focus on improving sensor calibration, data synchronization, and machine learning models to handle diverse real-world conditions. These advancements will increase the accuracy and scalability of smartphone-based monitoring systems, particularly for urban areas requiring real-time data for rapid maintenance. Full article

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16 pages, 5216 KiB

Open AccessArticle

Shape Accuracy Improvement of the Flange Turning Process in Aluminum Aerosol Can Production

by Istvan Sztankovics, Csaba Felho, Krisztina Kun-Bodnar and Zsolt Maros

Eng 2024, 5(4), 3381-3396; https://doi.org/10.3390/eng5040176 - 15 Dec 2024

Abstract

This study investigates the flange turning process in the production of aluminum aerosol bottles. Aluminum discs are lubricated, extruded, trimmed, washed, painted, and lacquered before undergoing necking, where flange turning ensures a secure, aesthetically pleasing fit. Errors in flange turning, such as uneven [...] Read more.

This study investigates the flange turning process in the production of aluminum aerosol bottles. Aluminum discs are lubricated, extruded, trimmed, washed, painted, and lacquered before undergoing necking, where flange turning ensures a secure, aesthetically pleasing fit. Errors in flange turning, such as uneven or tapered surfaces, can compromise bottle functionality and appearance. To address this, experiments were performed with different tool geometries, feed rates, and rotational speeds. The investigations aimed to achieve flat, consistent flange surfaces with minimal deviation from the desired geometry. Two main variables were examined: a 1 s waiting time at the end position and variations in feed rate and cutting depth. The waiting time improved flatness, halving surface deviations, while regrinding the tool reduced flatness errors to a tenth of the original values. Higher feed rates and speeds also enhanced surface quality, with flatness errors ranging from 371 μm to 75 μm. Overall, this study demonstrates that optimizing parameters like cutting angle, feed rate, and rotational speed, along with a waiting period, significantly enhances surface accuracy. These findings support more efficient production processes for aluminum aerosol bottles. Full article

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23 pages, 17144 KiB

Open AccessArticle

Fabrication of Black Silicon Antireflection Coatings to Enhance Light Harvesting in Photovoltaics

by Klodian Dhoska, Evjola Spaho and Uljan Sinani

Eng 2024, 5(4), 3358-3380; https://doi.org/10.3390/eng5040175 - 14 Dec 2024

Abstract

Black silicon has attracted significant interest for various engineering applications, including solar cells, due to its ability to create highly absorbent surfaces or interfaces for light. It enhances light absorption in crystalline solar cells, improving the efficiency of converting incident light into electricity [...] Read more.

Black silicon has attracted significant interest for various engineering applications, including solar cells, due to its ability to create highly absorbent surfaces or interfaces for light. It enhances light absorption in crystalline solar cells, improving the efficiency of converting incident light into electricity for photovoltaic applications. This research focused on fabricating nanostructures that played a critical role in enhancing light absorption in the upper layers of solar cells. These nanostructures were created using the black silicon method, forming a layer known as “black silicon”. The coating not only improved the efficiency of crystalline solar cells but also enhanced their stability. The antireflection coating, composed of nanostructures with various shapes, including conical, pillar-like, and spike-like forms, achieved a reflectivity as low as 10% in the spectral range of 400–700 nm. This corresponded to a sample with α = 0.85 and a chuck bias of 4 W. An Inductively Coupled Plasma Reactive Ion Etching (ICP RIE) machine was employed to develop and control the specific shape, size, and density of the fabricated black silicon, which was then subjected to testing. The efficiency of the black silicon photovoltaic cell was 23.3%. Full article

(This article belongs to the Special Issue Emerging Trends in Materials Engineering for Clean Energy Applications)

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23 pages, 10797 KiB

Open AccessArticle

3E Comparative Analysis of Brayton–ORC Cycle Using Two Thermal Sources: Solar Energy and Coconut Shell Biomass

by José Manuel Tovar, Guillermo Valencia Ochoa and Branda Molina

Eng 2024, 5(4), 3335-3357; https://doi.org/10.3390/eng5040174 - 11 Dec 2024

Abstract

Solar energy and biomass offer sustainable alternatives to meet the energy demand and reduce the environmental impact of fossil fuels. In this study, through mass and energy balances, a comparative analysis of energy, exergy, and environmental impact (LCA) was conducted on two renewable [...] Read more.

Solar energy and biomass offer sustainable alternatives to meet the energy demand and reduce the environmental impact of fossil fuels. In this study, through mass and energy balances, a comparative analysis of energy, exergy, and environmental impact (LCA) was conducted on two renewable thermal sources: solar energy and coconut shell biomass, both coupled to a supercritical CO₂ Brayton cycle (sCO₂) with an organic Rankine cycle (ORC) for waste heat recovery. The sCO₂–ORC–biomass configuration showed higher exergy efficiency (41.1%) and lower exergy destruction (188.88 kW) compared to the sCO₂–ORC–solar system (23.76% and 422.63 kW). Thermal efficiency (50.6%) and net power output (131.73 kW) were similar for both sources. However, the solar system (204,055.57 kg CO₂-equi) had an 85.6% higher environmental impact than the biomass system (109,933.63 kg CO₂-equi). Additionally, the construction phase contributed ~95% of emissions in both systems, followed by decommissioning (~4.5%) and operation (~0.1%). Finally, systems built with aluminum generate a higher carbon footprint than those with copper, with differences of 2% and 3.2% in sCO₂–ORC–solar and sCO₂–ORC–biomass, respectively. This study and an economic analysis make these systems viable thermo-sustainable options for clean energy generation. Full article

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19 pages, 3927 KiB

Open AccessArticle

Modeling of Oil–Water Two-Phase Flow in Horizontal Pipes Using CFD for the Prediction of Flow Patterns

by Octavio Andrés González-Estrada, Santiago Hernández and Germán González-Silva

Eng 2024, 5(4), 3316-3334; https://doi.org/10.3390/eng5040173 - 11 Dec 2024

Abstract

A computational fluid dynamics study of the horizontal oil–water flow was performed using the Eulerian–Eulerian and mixture multiphase models in conjunction with the realizable k–ε turbulence model for the characterization of flow patterns. The experimental tests were carried out using water [...] Read more.

A computational fluid dynamics study of the horizontal oil–water flow was performed using the Eulerian–Eulerian and mixture multiphase models in conjunction with the realizable k–ε turbulence model for the characterization of flow patterns. The experimental tests were carried out using water and mineral oil with a density of 880 kg/m³ and a viscosity of 180 cP, varying the superficial velocities of both fluids in ranges of 0.1–1.2 m/s and 0.1–0.5 m/s, respectively. The numerical model was defined under the same initial and boundary conditions as in the experiment. Moreover, the model is defined such that entering the fluids in a mixed state, the stratified pattern could form adequately with the two multiphase models. Although the Eulerian–Eulerian model, together with the geometric reconstruction scheme, allowed us to visualize the three-dimensional dispersed patterns in a very similar way to the experimental results, the mixture model did not exhibit such similarity, especially in the oil-in-water dispersions. Additionally, the Eulerian–Eulerian model was able to predict the experimental holdup values with an average error of 15.2%. Full article

(This article belongs to the Special Issue GeoEnergy Science and Engineering 2024)

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32 pages, 5286 KiB

Open AccessReview

A Review of Passenger Counting in Public Transport Concepts with Solution Proposal Based on Image Processing and Machine Learning

by Aleksander Radovan, Leo Mršić, Goran Đambić and Branko Mihaljević

Eng 2024, 5(4), 3284-3315; https://doi.org/10.3390/eng5040172 - 10 Dec 2024

Abstract

The accurate counting of passengers in public transport systems is crucial for optimizing operations, improving service quality, and planning infrastructure. It can also contribute to reducing the number of public transport lines where a high number of vehicles is not needed in certain [...] Read more.

The accurate counting of passengers in public transport systems is crucial for optimizing operations, improving service quality, and planning infrastructure. It can also contribute to reducing the number of public transport lines where a high number of vehicles is not needed in certain periods during the year, but also by increasing the number of lines where the need is increased. This paper provides a comprehensive review of current methodologies and technologies used for passenger counting, without the actual implementation of the automatic passenger counting system (APC), but with a proposal based on image processing and machine learning techniques and concepts, since it represents one of the most used approaches. The research explores various technologies and algorithms, like card swiping, infrared, weight and ultrasonic sensors, RFID, Wi-Fi, Bluetooth, LiDAR, thermos cameras, including CCTV cameras and traditional computer vision methods, and advanced deep learning approaches, highlighting their strengths and limitations. By analyzing recent advancements and case studies, this review aims to offer insights into the effectiveness, scalability, and practicality of different passenger counting solutions and offers a solution proposal. The research also analyzed the current General Data Protection Regulation (GDPR) that applies to the European Union and how it affects the use of systems like this. Future research directions and potential areas for technological innovation are also discussed to guide further developments in this field. Full article

(This article belongs to the Special Issue Artificial Intelligence for Engineering Applications)

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25 pages, 75362 KiB

Open AccessArticle

Comprehensive Technical Inspection of a Medieval Bridge (Ponte de Vilanova, in Allariz) Using Microtechnological Tools

by Rubén Rodríguez Elizalde

Eng 2024, 5(4), 3259-3283; https://doi.org/10.3390/eng5040171 - 10 Dec 2024

Abstract

Ponte de Vilanova, a masonry bridge, was built in Allariz, Galicia in the 13th–14th centuries. It is still standing. The structure, generally well preserved, shows minor deformations and wear signs caused by environmental factors. To conduct a comprehensive assessment without impacting the bridge’s [...] Read more.

Ponte de Vilanova, a masonry bridge, was built in Allariz, Galicia in the 13th–14th centuries. It is still standing. The structure, generally well preserved, shows minor deformations and wear signs caused by environmental factors. To conduct a comprehensive assessment without impacting the bridge’s integrity, drones equipped with thermal and underwater imaging technology were employed. Aerial inspections revealed vegetation growth and minor efflorescence (salt deposits) in some areas, while aerial thermography detected temperature variations along the stone joints, indicating the presence of moisture. The granite blocks comprising the bridge showed consistent quality and preservation. The underwater inspection confirmed that the bridge’s piers are well set on the riverbed, with no major damage observed, ruling out the immediate need for repair. This approach allowed a thorough evaluation of submerged parts without requiring divers, enhancing safety and reducing costs. Full article

(This article belongs to the Section Materials Engineering)

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20 pages, 2708 KiB

Open AccessArticle

Benchmarking a Novel Particle Swarm Optimization Dynamic Model Versus HOMER in Optimally Sizing Grid-Integrated Hybrid PV–Hydrogen Energy Systems

by Ayatte I. Atteya and Dallia Ali

Eng 2024, 5(4), 3239-3258; https://doi.org/10.3390/eng5040170 - 9 Dec 2024

Abstract

This paper presents the development of an Artificial Intelligence (AI)-based integrated dynamic hybrid PV-H₂ energy system model together with a reflective comparative analysis of its performance versus that of the commercially available HOMER software. In this paper, a novel Particle Swarm Optimization [...] Read more.

This paper presents the development of an Artificial Intelligence (AI)-based integrated dynamic hybrid PV-H₂ energy system model together with a reflective comparative analysis of its performance versus that of the commercially available HOMER software. In this paper, a novel Particle Swarm Optimization (PSO) dynamic system model is developed by integrating a PSO algorithm with a precise dynamic hybrid PV-H₂ energy system model that is developed to accurately simulate the hybrid system by considering the dynamic behaviour of its individual system components. The developed novel model allows consideration of the dynamic behaviour of the hybrid PV-H₂ energy system while optimizing its sizing within grid-connected buildings to minimize the levelized cost of energy and maintain energy management across the hybrid system components and the grid in feeding the building load demands. The developed model was applied on a case-study grid-connected building to allow benchmarking of its results versus those from HOMER. Benchmarking showed that the developed model’s optimal sizing results as well as the corresponding levelized cost of energy closely match those from HOMER. In terms of energy management, the benchmarking results showed that the strategy implemented within the developed model allows maximization of the green energy supply to the building, thus aligning with the net-zero energy transition target, while the one implemented in HOMER is based on minimizing the levelized cost of energy regardless of the green energy supply to the building. Another privilege revealed by benchmarking is that the developed model allows a more realistic quantification of the hydrogen output from the electrolyser because it considers the dynamic behaviour of the electrolyser in response to the varying PV input, and also allows a more realistic quantification of the electricity output from the fuel cell because it considers the dynamic behaviour of the fuel cell in response to the varying hydrogen levels stored in the tank. Full article

(This article belongs to the Special Issue Artificial Intelligence for Engineering Applications)

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27 pages, 1888 KiB

Open AccessArticle

On the Game-Based Approach to Optimal Design

by Vladimir Kobelev

Eng 2024, 5(4), 3212-3238; https://doi.org/10.3390/eng5040169 - 4 Dec 2024

Abstract

A game problem of structural design is defined as a problem of playing against external circumstances. There are two classes of players, namely the “ordinal” and “cardinal” players. The ordinal players, designated as the “operator” and “nature”, endeavor to, respectively, minimize or maximize [...] Read more.

A game problem of structural design is defined as a problem of playing against external circumstances. There are two classes of players, namely the “ordinal” and “cardinal” players. The ordinal players, designated as the “operator” and “nature”, endeavor to, respectively, minimize or maximize the payoff function, operating within the constraints of limited resources. The fundamental premise of this study is that the action of player “nature” is a priori unknown. Statistical decision theory addresses decision-making scenarios where these probabilities, whether or not they are known, must be considered. The solution to the substratum game is expressed as a value of the game “against nature”. The structural optimization extension of the game considers the value of the game “against nature” as the function of certain parameters. Thus, the value of the game is contingent upon the design parameters. The cardinal players, “designers”, choose the design parameters. There are two formulations of optimization. For the single cardinal player, the pursuit of the maximum and minimum values of the game reduces the problem of optimal design. In the second formulation, there are multiple cardinal players with conflicting objectives. Accordingly, the superstratum game emerges, which addresses the interests of the superstratum players. Finally, the optimal design problems for games with closed forms are presented. The game formulations could be applied for optimal design with uncertain loading, considering “nature” as the source of uncertainty. Full article

(This article belongs to the Special Issue Feature Papers in Eng 2024)

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20 pages, 588 KiB

Open AccessReview

Optimization of Structures and Composite Materials: A Brief Review

by André Ferreira Costa Vieira, Marcos Rogério Tavares Filho, João Paulo Eguea and Marcelo Leite Ribeiro

Eng 2024, 5(4), 3192-3211; https://doi.org/10.3390/eng5040168 - 2 Dec 2024

Abstract

Neural networks (NNs) have revolutionized various fields, including aeronautics where it is applied in computational fluid dynamics, finite element analysis, load prediction, and structural optimization. Particularly in optimization, neural networks and deep neural networks are extensively employed to enhance the efficiency of genetic [...] Read more.

Neural networks (NNs) have revolutionized various fields, including aeronautics where it is applied in computational fluid dynamics, finite element analysis, load prediction, and structural optimization. Particularly in optimization, neural networks and deep neural networks are extensively employed to enhance the efficiency of genetic algorithms because, with this tool, it is possible to speed up the finite element analysis process, which will also speed up the optimization process. The main objective of this paper is to present how neural networks can help speed up the process of optimizing the geometries and composition of composite structures (dimension, topology, volume fractions, reinforcement architecture, matrix/reinforcement composition, etc.) compared to the traditional optimization methods. This article stands out by showcasing not only studies related to aeronautics but also those in the field of mechanics, emphasizing that the underlying principles are shared and applicable to both domains. The use of NNs as a surrogate model has been demonstrated to be a great tool for the optimization process; some studies have shown that the NNs are accurate in their predictions, with an MSE of

1 \times 10^{- 5}

and MAE of 0.007%. It has also been observed that its use helps to reduce optimization time, such as up to a speed 47.5 times faster than a full aeroelastic model. Full article

(This article belongs to the Special Issue Feature Papers in Eng 2024)

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