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Eng, Volume 5, Issue 2 (June 2024) – 26 articles

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9 pages, 2317 KiB  
Article
Efficient Reduction of Carbon Tetrachloride in an Electrochemical Reactor with a Three-Dimensional Electrode
by Víctor M. Molina, Esteban Moreno-Toral and Antonio Ramos-Carrillo
Eng 2024, 5(2), 983-991; https://doi.org/10.3390/eng5020054 - 26 May 2024
Viewed by 197
Abstract
A selective electrochemical synthesis of chloroform from carbon tetrachloride (CT) in a laboratory-scale electrochemical reactor using a carbon felt three-dimensional electrode is studied. The characterization of the electrochemical reactor from the point of view of material transport was carried out, obtaining good correlations [...] Read more.
A selective electrochemical synthesis of chloroform from carbon tetrachloride (CT) in a laboratory-scale electrochemical reactor using a carbon felt three-dimensional electrode is studied. The characterization of the electrochemical reactor from the point of view of material transport was carried out, obtaining good correlations both in the adjustment to a simple bath reactor model and the adjustment to a piston-flow model, and the operating parameters were obtained, such as the material transport coefficient or the limiting intensity. The galvanostatic electrolysis of CT in the filter-press reactor obtained good values for current efficiency and selectivity, so that only hydrogen was obtained as a by-product. With respect to the use of flat electrodes, the three-dimensional carbon felt electrode improves the results in all the studied parameters under identical experimental conditions. Full article
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16 pages, 3505 KiB  
Article
Assessing the Suitability of Automation Using the Methods–Time–Measurement Basic System
by Malte Jakschik, Felix Endemann, Patrick Adler, Lennart Lamers and Bernd Kuhlenkötter
Eng 2024, 5(2), 967-982; https://doi.org/10.3390/eng5020053 - 24 May 2024
Viewed by 250
Abstract
Due to its high complexity and the varied assembly processes, hybrid assembly systems characterized by human–robot collaboration (HRC) are meaningful. Suitable use cases must be identified efficiently to ensure cost-effectiveness and successful deployment in the respective assembly systems. This paper presents a method [...] Read more.
Due to its high complexity and the varied assembly processes, hybrid assembly systems characterized by human–robot collaboration (HRC) are meaningful. Suitable use cases must be identified efficiently to ensure cost-effectiveness and successful deployment in the respective assembly systems. This paper presents a method for evaluating the potential of HRC to derive automation suitability based on existing or to-be-collected time data. This should enable a quick and favorable statement to be made about processes, for efficient application in potential analyses. The method is based on the Methods–Time–Measurement Basic System (MTM-1) procedure, widely used in the industry. This ensures good adaptability in an industrial context. It extends existing models and examines how much assembly activities and processes can be optimized by efficiently allocating between humans and robots. In the process model, the assembly processes are subdivided and analyzed with the help of the specified MTM motion time system. The suitability of the individual activities and sub-processes for automation are evaluated based on criteria derived from existing methods. Two four-field matrices were used to interpret and classify the analysis results. The process is assessed using an example product from electrolyzer production, which is currently mainly assembled by hand. To achieve high statement reliability, further work is required to classify the results comprehensively. Full article
(This article belongs to the Special Issue Feature Papers in Eng 2024)
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9 pages, 6151 KiB  
Article
Innovative Integration of Triboelectric Nanogenerators into Signature Stamps for Energy Harvesting, Self-Powered Electronic Devices, and Smart Applications
by Lakshakoti Bochu, Supraja Potu, Madathil Navaneeth, Uday Kumar Khanapuram, Rakesh Kumar Rajaboina and Prakash Kodali
Eng 2024, 5(2), 958-966; https://doi.org/10.3390/eng5020052 - 23 May 2024
Viewed by 295
Abstract
In this manuscript, we present a novel approach for integrating Triboelectric Nanogenerators (TENGs) into signature stamps, termed Stamp TENG (S-TENG). We have modified a commercially available stamp holder to integrate triboelectric layers for multiple applications like effective energy harvesting, sensing, and embedded electronics [...] Read more.
In this manuscript, we present a novel approach for integrating Triboelectric Nanogenerators (TENGs) into signature stamps, termed Stamp TENG (S-TENG). We have modified a commercially available stamp holder to integrate triboelectric layers for multiple applications like effective energy harvesting, sensing, and embedded electronics for data prediction. S-TENG has been further explored in remote monitoring systems for elderly individuals and for gathering real-time statistics regarding persons or events at specific locations. The S-TENG is fabricated using FEP and Al as functional layers. It demonstrates an output voltage of 310 V, a current of 165 μA, and a power density of 14.8 W/m2. The simplicity of the S-TENG’s design is noteworthy. Its ability to generate energy through simple, repetitive stamping actions, which anyone can perform without specialized training, stands out as a key feature. The device is also designed for ease of use, being handheld and user-friendly. Its flexible and adaptable structure ensures that individuals with varying physical capabilities can comfortably operate it. An impressive capability of the TENG is its ability to illuminate 320 LEDs with each stamp press momentarily. Furthermore, using energy management circuits, the S-TENG can power small electronic gadgets such as digital watches and thermometers for a few seconds. In addition, when integrated with electronics, the S-TENG shows great potential in data prediction for various practical applications. Full article
(This article belongs to the Section Electrical and Electronic Engineering)
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14 pages, 4126 KiB  
Article
NACA 2412 Drag Reduction Using V-Shaped Riblets
by Smitha Mol Selvanose, Siva Marimuthu, Abdul Waheed Awan and Kamran Daniel
Eng 2024, 5(2), 944-957; https://doi.org/10.3390/eng5020051 - 23 May 2024
Viewed by 284
Abstract
This research focuses on addressing a significant concern in the aviation industry, which is drag. The primary objective of this project is to achieve drag reduction through the implementation of riblets on a wing featuring the NACA 2412 aerofoil, operating at subsonic speeds. [...] Read more.
This research focuses on addressing a significant concern in the aviation industry, which is drag. The primary objective of this project is to achieve drag reduction through the implementation of riblets on a wing featuring the NACA 2412 aerofoil, operating at subsonic speeds. Riblets, with the flow direction on wing surfaces, have demonstrated the potential to effectively decrease drag in diverse applications. This investigation includes computational analysis within the ANSYS Workbench framework, employing a polyhedral mesh model. The scope of this research encompasses the analysis of both a conventional wing and a modified wing with riblets. A comparative analysis is conducted to assess variations in drag values between the two configurations. Parameters, including geometry, dimensions, and riblet placement at varying angles of attack, are explored to comprehend their impact on drag reduction. Notably, 15.6% and 23% reductions in drag were identified at a 16-degree angle of attack with midspan and three-riblet models, separately. The computational mesh and method were validated using appropriate techniques. Full article
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12 pages, 1914 KiB  
Article
Novel Synthesis of Nanocalcite from Phosphogypsum and Cesium Carbonate: Control and Optimization of Particle Size
by Meryem Bensemlali, Badreddine Hatimi, Asmae Sanad, Layla El Gaini, Meryeme Joudi, Najoua Labjar, Hamid Nasrellah, Abdellatif Aarfane and Mina Bakasse
Eng 2024, 5(2), 932-943; https://doi.org/10.3390/eng5020050 - 21 May 2024
Viewed by 215
Abstract
This study investigates a controlled synthesis and particle size optimization of nanocalcite particles using phosphogypsum, a waste byproduct from the phosphate fertilizer industry, and cesium carbonate (Cs2CO3), a common carbonate source. The effects of synthesis parameters, including temperature and [...] Read more.
This study investigates a controlled synthesis and particle size optimization of nanocalcite particles using phosphogypsum, a waste byproduct from the phosphate fertilizer industry, and cesium carbonate (Cs2CO3), a common carbonate source. The effects of synthesis parameters, including temperature and pH, on the size, morphology, and crystallinity of the synthesized nanocalcite particles were systematically examined. The optimized synthesis conditions for obtaining nanocalcite particles with desired properties are discussed. The synthesized nanocalcite particles were characterized using various techniques, such as XRD, FTIR, and SEM, to analyze their crystal structure, morphology, and elemental composition. Particle sizes were determined using the Debye–Scherrer method, and accordingly, nanometric sizes were achieved. The potential applications of the synthesized nanocalcite particles in cementitious materials, agriculture, and drug delivery are highlighted. This research provides valuable insights into the sustainable synthesis and size optimization of nanocalcite particles from phosphogypsum and Cs2CO3 at a controlled temperature and pH. Full article
(This article belongs to the Section Materials Engineering)
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14 pages, 1957 KiB  
Article
Process-Driven Layout Optimization of a Portable Hybrid Manufacturing Robotic Cell Structure
by Harry Bikas, Dimitrios Manitaras, Thanassis Souflas and Panagiotis Stavropoulos
Eng 2024, 5(2), 918-931; https://doi.org/10.3390/eng5020049 - 20 May 2024
Viewed by 215
Abstract
Hybrid manufacturing combines manufacturing processes (typically additive manufacturing and machining) exploiting the benefits of each and enabling repair scenarios. Such an approach can be integrated with a robot, and if made portable, can form a flexible machine tool that can be easily transported [...] Read more.
Hybrid manufacturing combines manufacturing processes (typically additive manufacturing and machining) exploiting the benefits of each and enabling repair scenarios. Such an approach can be integrated with a robot, and if made portable, can form a flexible machine tool that can be easily transported anywhere to enable repairs in the field. However, the design of the load-bearing structure determines its transportability, and its stiffness plays a crucial functional role under dynamic loads and affects the product quality. Finding the right balance between weight and stiffness requires accurate boundary conditions and an effective design. In this work, a method is proposed towards process-driven optimization of a portable manufacturing cell structure. The dynamic cutting forces are determined through a machining process model and, via a simplified model of the robot arm, the forces at the base of the robot are estimated. Since the frame consists of beams, the layout optimization method is applied, using the estimated process forces as boundary conditions to optimize the arrangement of beams. The proposed method achieved 0.05 mm displacement in the load-bearing structure under milling and an acceptable accuracy of the position of a hole’s center during drilling, while the overall weight reduced by 17.6%. Full article
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23 pages, 6172 KiB  
Article
An Efficient Approach for Damage Identification of Beams Using Mid-Span Static Deflection Changes
by Quoc-Bao Nguyen and Huu-Hue Nguyen
Eng 2024, 5(2), 895-917; https://doi.org/10.3390/eng5020048 - 20 May 2024
Viewed by 208
Abstract
In structural health monitoring, determining the location and index of damage is a critical task in order to ensure the safe operation of the construction project and to enable the early recovery of losses. This paper presents a novel method for identifying damage [...] Read more.
In structural health monitoring, determining the location and index of damage is a critical task in order to ensure the safe operation of the construction project and to enable the early recovery of losses. This paper presents a novel method for identifying damage location and damage index in simply supported (SS) beams by analyzing deflection changes at the mid-span point. Theoretical equations for mid-span deflection of simply supported beams with local damage are derived based on the principle of Virtual Work. Utilizing mid-span deflection, formulas for deflection change (DC) between two structural states, along with the first and second derivatives of DC at the mid-span point, are developed. The method of determining the location and damage index is then extended from intact beams to cases of beams with multiple damage zones and from damaged beams to beams with new failures. The graphical analysis of these quantities facilitates the determination of the number, location, and index of new damages. Various case studies on simply supported beams, involving one, two, and four damage zones at different positions and with varying damage indexes, are examined. The comparison of the theoretical method with the numerical simulations using Midas FEA NX 2020 (v1.1) software yields consistent results, affirming the accuracy and efficacy of the proposed approach in identifying and determining the damage locations as well as the damage indices. Full article
(This article belongs to the Section Chemical, Civil and Environmental Engineering)
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14 pages, 6858 KiB  
Article
Comparative Analysis of Finite Element Formulations for Simulating Hot Forming of Ti-6Al-4V Aerospace Components
by Olivier Pantalé, Sharan Raj Rangasamy Mahendren and Olivier Dalverny
Eng 2024, 5(2), 881-894; https://doi.org/10.3390/eng5020047 - 13 May 2024
Viewed by 355
Abstract
This study presents a comprehensive finite element analysis to compare the performance of different element formulations (classic shell elements, solid elements, and continuum shell elements) in simulating the hot-forming process at 725 °C of a complex Ti-6Al-4V aerospace component with an initial blank [...] Read more.
This study presents a comprehensive finite element analysis to compare the performance of different element formulations (classic shell elements, solid elements, and continuum shell elements) in simulating the hot-forming process at 725 °C of a complex Ti-6Al-4V aerospace component with an initial blank thickness of 1.6 mm (0.063 inches). The Ti-6Al-4V blank is modeled as a deformable body exhibiting anisotropic plastic behavior, whereas the forming tools (matrix and punch) are assumed to be rigid bodies. The simulation accounts for temperature and strain rate effects on the material properties, incorporating phenomena such as friction and anisotropy. Three different element types are studied and compared: S4R and S4 (classic shells), C3D8R and C3D8 (solids), and SC8R (continuum shell with reduced integration). Finally, the model is validated by comparing the predicted final part geometry, especially the thickness distribution, against the experimental measurements. The model can also predict the springback effect on the final geometry. The SC8R continuum shell element provides the smoothest representation of thickness variations along critical regions of the final part. The study highlights the importance of selecting the appropriate element type for the accurate simulation of hot-forming processes involving large deformations and complex contact conditions. The ability of continuum shell elements to accurately capture the thickness variations makes them an ideal candidate for such applications. Full article
(This article belongs to the Section Materials Engineering)
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30 pages, 5852 KiB  
Review
Inertial Propulsion Devices: A Review
by Christopher G. Provatidis
Eng 2024, 5(2), 851-880; https://doi.org/10.3390/eng5020046 - 13 May 2024
Viewed by 474
Abstract
Google Scholar produces about 278 hits for the term “inertial propulsion”. If patents are also included, the number of hits increases to 536. This paper discusses, in a critical way, some characteristic aspects of this controversial topic. The review starts with the halteres [...] Read more.
Google Scholar produces about 278 hits for the term “inertial propulsion”. If patents are also included, the number of hits increases to 536. This paper discusses, in a critical way, some characteristic aspects of this controversial topic. The review starts with the halteres of athletes in the Olympic games of ancient times and then continues with some typical devices which have been developed and/or patented from the second quarter of the twentieth century to the present day. Full article
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17 pages, 7504 KiB  
Article
Influence of a Shaft Shoulder on the Torsional Load-Bearing Behaviour of Trochoidal Profile Contours as Positive Shaft–Hub Connections
by Masoud Ziaei, Marcus Selzer and Heiko Sommer
Eng 2024, 5(2), 834-850; https://doi.org/10.3390/eng5020045 - 11 May 2024
Viewed by 309
Abstract
Shafts with a stepped shoulder are particularly well known in the field of drive technology. In combination with a form-fit shaft–hub connection, the shaft shoulder fixes the hub on the shaft as well as being responsible for the absorption of the axial forces. [...] Read more.
Shafts with a stepped shoulder are particularly well known in the field of drive technology. In combination with a form-fit shaft–hub connection, the shaft shoulder fixes the hub on the shaft as well as being responsible for the absorption of the axial forces. With profiled shafts, there is a notch overlay in the shaft shoulder, involving the shaft shoulder and profile. If the hub is also connected with the profiled shaft, the hub edge acts as an additional notch in the shaft shoulder area. The multiple resulting notches have not previously been part of research activities in the field of innovative trochoidal profile connections. Compared to conventional positive-locking connections, such as the keyway connection or the involute splined shaft profile, the favourable features of trochoidal profiles have only been based on connections with stepless shafts without a shoulder in previous studies. Accordingly, this article addresses numerical and experimental investigations of trochoidal profile connections with offset shafts for pure torsional loading. Focusing on a hybrid trochoid with four eccentricities and six drivers, a well-founded numerical and experimental investigation was carried out with numerous fatigue tests. In addition, the influence of a shaft shoulder was also demonstrated on simple epitrochoidal and hypotrochoidal profiles. Full article
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15 pages, 2639 KiB  
Article
An Integrated Infrastructure Resilience Approach, from the Geotechnical Asset to the Transport Network
by Georgios Belokas, Charalampos Saroglou, Tatiana P. Moschovou and Eleni I. Vlahogianni
Eng 2024, 5(2), 819-833; https://doi.org/10.3390/eng5020044 - 10 May 2024
Viewed by 407
Abstract
The main objective of this work is to present a comprehensive and integrated methodology to enhance the resilience of transportation critical infrastructure (TCI), focusing on the interplay between geotechnical assets and the transport network. Societies are greatly dependent on transport infrastructure systems, and [...] Read more.
The main objective of this work is to present a comprehensive and integrated methodology to enhance the resilience of transportation critical infrastructure (TCI), focusing on the interplay between geotechnical assets and the transport network. Societies are greatly dependent on transport infrastructure systems, and as the mobility of passengers and the transport of freight is continuously growing, a disruption due to natural or man-made hazards creates significant impacts and dysfunctionalities on their operation and necessitates response measures to minimize vulnerability and ensure continuous functionality and robustness through resilience. Therefore, resilience quantification allows the design of ad hoc operation action plans before, during, and after a disruption, considering the dynamics of societal, ecological, and technological (SET) environments. The current work focuses on resilience quantification methodologies for TCIs and on the influence of single geotechnical asset (i.e., slope failure) resilience capacity on the overall system (i.e., national road network) resilience. Two case studies of unexpected transport network disruptions that took place in Greece are presented, and resilience metrics and performance indicators are applied to quantify the influence of the recovery stage. Full article
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18 pages, 2340 KiB  
Article
Minimum Shear Reinforcement for Reactive Powder Concrete Beams
by Hussein Kareem Sultan and Ghasan Fahim Huseien
Eng 2024, 5(2), 801-818; https://doi.org/10.3390/eng5020043 - 8 May 2024
Viewed by 412
Abstract
The aim of this research was to determine the minimal requirements for shear reinforcement for reactive powder concrete (RPC) rectangular cross-sectional beams with a compressive strength of 157 MPa and a steel fiber volume content of 2.0% that remained constant for all the [...] Read more.
The aim of this research was to determine the minimal requirements for shear reinforcement for reactive powder concrete (RPC) rectangular cross-sectional beams with a compressive strength of 157 MPa and a steel fiber volume content of 2.0% that remained constant for all the tested beams. Additionally, the recommendations of KCI-2012 and AFGC-2013 for the design of RPC beams as well as the shear design requirements of ACI 314-2014 when applied to RPC beams were studied. Utilizing a three-dimensional finite element program, a computational model was designed for forecasting the deformations and shear strength of the examined RPC beams. Both the shear-span-to-depth relationship (a/d) and the minimal reinforcement web ratio, represented by the distance between stirrups and the diameter of the stirrup bars, are the key study parameters in this regard. According to this study’s experimental findings, increasing the given reinforcement of the web ratio has little influence on both the ultimate shear strength as well as the diagonal cracking strength of the beams. Additionally, the findings demonstrated that the ACI 318-2014 maximum stirrup spacing requirement of 0.5 d can safely be extended to 0.75 d for beams that are relatively short. Compared to what ACI 318-2014 mandates, the suggestions of AFGC-2013 and KCI-2012 are more cautious and safe. According to the AFGC-2013 criteria, the mean proportion of Vfb to projected Vu,AFGC is roughly 58.3%, whereas the mean proportion of vs. and Vc is just 41.7%. The deformation response and ultimate shear strength of the examined RPC beams were well predicted by the designed model using finite elements when metal fibers were taken into account. Full article
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17 pages, 1901 KiB  
Review
Automatic Reconstruction of 3D Models from 2D Drawings: A State-of-the-Art Review
by Sofia Feist, Luís Jacques de Sousa, Luís Sanhudo and João Poças Martins
Eng 2024, 5(2), 784-800; https://doi.org/10.3390/eng5020042 - 8 May 2024
Viewed by 469
Abstract
Among the methods of 3D reconstruction, the automatic generation of 3D models from building documentation is one of the most accessible and inexpensive. For 30 years, researchers have proposed multiple methods to automatically generate 3D models from 2D drawings. This study compiles this [...] Read more.
Among the methods of 3D reconstruction, the automatic generation of 3D models from building documentation is one of the most accessible and inexpensive. For 30 years, researchers have proposed multiple methods to automatically generate 3D models from 2D drawings. This study compiles this research and discusses the different methods used to generate 3D models from 2D drawings. It offers a critical review of these methods, focusing on the coverage and completeness of the reconstruction process. This review allows us to identify the research gaps in the literature, and opportunities for improvement are identified for future research. Full article
(This article belongs to the Section Chemical, Civil and Environmental Engineering)
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34 pages, 6815 KiB  
Review
Advancing Earth-Based Construction: A Comprehensive Review of Stabilization and Reinforcement Techniques for Adobe and Compressed Earth Blocks
by Gabo Cyprien Bailly, Yassine El Mendili, Athanas Konin and Eliane Khoury
Eng 2024, 5(2), 750-783; https://doi.org/10.3390/eng5020041 - 30 Apr 2024
Viewed by 726
Abstract
This comprehensive literature review investigates the impact of stabilization and reinforcement techniques on the mechanical, hygrothermal properties, and durability of adobe and compressed earth blocks (CEBs). Recent advancements in understanding these properties have spurred a burgeoning body of research, prompting a meticulous analysis [...] Read more.
This comprehensive literature review investigates the impact of stabilization and reinforcement techniques on the mechanical, hygrothermal properties, and durability of adobe and compressed earth blocks (CEBs). Recent advancements in understanding these properties have spurred a burgeoning body of research, prompting a meticulous analysis of 70 journal articles and conference proceedings. The selection criteria focused on key parameters including construction method (block type), incorporation of natural fibers or powders, partial or complete cement replacement, pressing techniques, and block preparation methods (adobe or CEB). The findings unearth several significant trends. Foremost, there is a prevailing interest in utilizing waste materials, such as plant matter, construction and demolition waste, and mining by-products, to fortify or stabilize earth blocks. Additionally, the incorporation of natural fibers manifests in a discernible reduction in crack size attributable to shrinkage, accompanied by enhancements in durability, mechanical strength, and thermal resistance. Moreover, this review underscores the imperative of methodological coherence among researchers to facilitate scalable and transposable results. Challenges emerge from the variability in base soil granulometry and disparate research standards, necessitating concerted efforts to harness findings effectively. Furthermore, this review illuminates a gap in complete lifecycle analyses of earthen structures, underscoring the critical necessity for further research to address this shortfall. It emphasizes the urgent need for deeper exploration of properties and sustainability indicators, recognizing the inherent potential and enduring relevance of earthen materials in fostering sustainable development. This synthesis significantly contributes to the advancement of knowledge in the field and underscores the continued importance of earth-based construction methodologies in contemporary sustainable practices. Full article
(This article belongs to the Section Chemical, Civil and Environmental Engineering)
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17 pages, 3468 KiB  
Article
Effects of Initial Small-Scale Material Nonlinearity on the Pre-Yield and Pre-Buckling Response of an Externally Pressurized Ring
by Reaz A. Chaudhuri and Deokjoo Kim
Eng 2024, 5(2), 733-749; https://doi.org/10.3390/eng5020040 - 30 Apr 2024
Viewed by 294
Abstract
The effects of initial small-scale material nonlinearity on the pre-yield and pre-buckling response of externally pressurized metallic (plane strain) perfect rings (very long cylindrical shells) is investigated. The cylindrically curved 16-node element, based on an assumed quadratic displacement field (in surface-parallel coordinates) and [...] Read more.
The effects of initial small-scale material nonlinearity on the pre-yield and pre-buckling response of externally pressurized metallic (plane strain) perfect rings (very long cylindrical shells) is investigated. The cylindrically curved 16-node element, based on an assumed quadratic displacement field (in surface-parallel coordinates) and the assumption of linear distribution of displacements through thickness (LDT), is employed to obtain the discretized system equations. The effect of initial small-scale material nonlinearity (assumed hypo-elastic) on the deformation and stress in the pre-yield and pre-buckling regime of a very long relatively thin metallic cylindrical shell (plane strain ring) is numerically investigated. These numerical results demonstrate that the enhanced responses for metallic rings due to initial small-scale nonlinearity are significant enough to not miss attentions from designers and operators of submersibles alike. Full article
(This article belongs to the Special Issue Feature Papers in Eng 2024)
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13 pages, 690 KiB  
Article
Preliminary Envelope for Large Transport Aircrafts Operating with Non-Primary Fuels AVGAS, MOGAS and F76-Dieso
by José Luis Díaz Palencia
Eng 2024, 5(2), 720-732; https://doi.org/10.3390/eng5020039 - 28 Apr 2024
Viewed by 318
Abstract
This study explores the operational implications and safety considerations of using non-primary fuels—AVGAS, MOGAS, and F76 Dieso—in military transport aircraft, against the backdrop of standard aviation fuels. Through an analysis of fuel properties such as vapor pressure, density, viscosity, freeze temperature, water solubility, [...] Read more.
This study explores the operational implications and safety considerations of using non-primary fuels—AVGAS, MOGAS, and F76 Dieso—in military transport aircraft, against the backdrop of standard aviation fuels. Through an analysis of fuel properties such as vapor pressure, density, viscosity, freeze temperature, water solubility, and thermal conductivity, this work outlines the operational envelopes for the mentioned non-primary fuels, highlighting the temperature and altitude limitations inherent to their use. The evaluation underscores the necessity of relevant testing, certification, and adherence to operational guidelines and constrains to ensure aircraft safety and reliability when standard fuels are unavailable, and hence, non-primary fuels may be required in special missions under emergency. Key findings include the specific altitude and temperature limitations for AVGAS and MOGAS to prevent fuel freezing and boiling, as well as the operational challenges posed by F76 Dieso due to its higher density and viscosity. The study also addresses the importance of managing water content in the fuel system, the flammability range of the non-primary fuels, and the considerations for fuel mixing to maintain aircraft performance and safety standards. This analysis aims to enhance the understanding of non-primary fuel usage in military transport aircraft, providing insights for system design, performance assessment, and the development of operational procedures to support military aviation in diverse operational scenarios. Full article
(This article belongs to the Section Chemical, Civil and Environmental Engineering)
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43 pages, 26325 KiB  
Review
Current Status, Sizing Methodologies, Optimization Techniques, and Energy Management and Control Strategies for Co-Located Utility-Scale Wind–Solar-Based Hybrid Power Plants: A Review
by Shree O. Bade, Ajan Meenakshisundaram and Olusegun S. Tomomewo
Eng 2024, 5(2), 677-719; https://doi.org/10.3390/eng5020038 - 18 Apr 2024
Viewed by 812
Abstract
The integration of renewable energy sources, such as wind and solar, into co-located hybrid power plants (HPPs) has gained significant attention as an innovative solution to address the intermittency and variability inherent in renewable systems among plant developers because of advancements in technology, [...] Read more.
The integration of renewable energy sources, such as wind and solar, into co-located hybrid power plants (HPPs) has gained significant attention as an innovative solution to address the intermittency and variability inherent in renewable systems among plant developers because of advancements in technology, economies of scale, and government policies. However, it is essential to examine different challenges and aspects during the development of a major work on large-scale hybrid plants. This includes the need for optimization, sizing, energy management, and a control strategy. Hence, this research offers a thorough examination of the present state of co-located utility-scale wind–solar-based HPPs, with a specific emphasis on the problems related to their sizing, optimization, and energy management and control strategies. The authors developed a review approach that includes compiling a database of articles, formulating inclusion and exclusion criteria, and conducting comprehensive analyses. This review highlights the limited number of peer-reviewed studies on utility-scale HPPs, indicating the need for further research, particularly in comparative studies. The integration of machine learning, artificial intelligence, and advanced optimization algorithms for real-time decision-making is highlighted as a potential avenue for addressing complex energy management challenges. The insights provided in this manuscript will be valuable for researchers aiming to further explore HPPs, contributing to the development of a cleaner, economically viable, efficient, and reliable power system. Full article
(This article belongs to the Special Issue Feature Papers in Eng 2024)
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20 pages, 7186 KiB  
Article
Numerical Analysis of Bearing Capacity in Deep Excavation Support Structures: A Comparative Study of Nailing Systems and Helical Anchors
by Seyyed Alireza Taghavi, Farhad Mahmoudi Jalali, Reza Moezzi, Reza Yeganeh Khaksar, Stanisław Wacławek, Mohammad Gheibi and Andres Annuk
Eng 2024, 5(2), 657-676; https://doi.org/10.3390/eng5020037 - 18 Apr 2024
Viewed by 665
Abstract
The increasing demand for deep excavations in construction projects emphasizes the necessity of robust support structures to ensure safety and stability. Support structures are critical in stabilizing excavation pits, with a primary focus on enhancing their bearing capacity. This paper employs finite element [...] Read more.
The increasing demand for deep excavations in construction projects emphasizes the necessity of robust support structures to ensure safety and stability. Support structures are critical in stabilizing excavation pits, with a primary focus on enhancing their bearing capacity. This paper employs finite element modeling techniques to conduct a numerical analysis of nails and helical anchors’ bearing capacity. To reinforce the stability of pit walls, selecting an appropriate method for guard structure construction is imperative. The chosen method should efficiently redistribute forces induced by soil mass weight, displacements, and potential loads in the pit vicinity to the ground. Various techniques, including trusses, piles, cross-bracing systems, nailing, and anchorage systems, are utilized for this purpose. The study evaluates numerical models for two guard structure configurations: nailing systems and helical anchorage. It examines the impact of parameters such as displacement, helical helix count, helix diameter variations, and the integration of nailing systems with helices. Comparative analyses are conducted, including displacement comparisons between different nailing systems and helical anchor systems, along with laboratory-sampled data. The research yields significant insights, with a notable finding highlighting the superior performance of helical bracings compared to nailing systems. The conclusions drawn from this study provide specific outcomes that contribute valuable knowledge to the field of deep excavation support structures, guiding future design and implementation practices. Full article
(This article belongs to the Special Issue Feature Papers in Eng 2024)
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28 pages, 2100 KiB  
Article
Damage Detection with Data-Driven Machine Learning Models on an Experimental Structure
by Yohannes L. Alemu, Tom Lahmer and Christian Walther
Eng 2024, 5(2), 629-656; https://doi.org/10.3390/eng5020036 - 17 Apr 2024
Cited by 1 | Viewed by 1301
Abstract
Various techniques have been employed to detect damage in civil engineering structures. Apart from the model-based approach, which demands the frequent updating of its corresponding finite element method (FEM)-built model, data-driven methods have gained prominence. Environmental and operational effects significantly affect damage detection [...] Read more.
Various techniques have been employed to detect damage in civil engineering structures. Apart from the model-based approach, which demands the frequent updating of its corresponding finite element method (FEM)-built model, data-driven methods have gained prominence. Environmental and operational effects significantly affect damage detection due to the presence of damage-related trends in their analyses. Time-domain approaches such as autoregression and metrics such as the Mahalanobis squared distance have been utilized to mitigate these effects. In the realm of machine learning (ML) models, their effectiveness relies heavily on the type and quality of the extracted features, making this aspect a focal point of attention. The objective of this work is therefore to deploy and observe potential feature extraction approaches used as input in training fully data-driven damage detection machine learning models. The most damage-sensitive segment (MDSS) feature extraction technique, which potentially treats signals under multiple conditions, is also proposed and deployed. It identifies potential segments for each feature coefficient under a defined criterion. Therefore, 680 signals, each consisting of 8192 data points, are recorded using accelerometer sensors at the Los Alamos National Laboratory in the USA. The data are obtained from a three-story 3D building frame and are utilized in this research for a mainly data-driven damage detection task. Three approaches are implemented to replace four missing signals with the generated ones. In this paper, multiple fast Fourier and wavelet-transformed features are employed to evaluate their performance. Most importantly, a power spectral density (PSD)-based feature extraction approach that considers the maximum variability criterion to identify the most sensitive segments is developed and implemented. The performance of the MDSS selection technique, proposed in this work, surpasses that of all 18 trained neural networks (NN) and recurrent neural network (RNN) models, achieving more than 80% prediction accuracy on an unseen prediction dataset. It also significantly reduces the feature dimension. Furthermore, a sensitivity analysis is conducted on signal segmentation, overlapping, the treatment of a training dataset imbalance, and principal component analysis (PCA) implementation across various combinations of features. Binary and multiclass classification models are employed to primarily detect and additionally locate and identify the severity class of the damage. The collaborative approach of feature extraction and machine learning models effectively addresses the impact of environmental and operational effects (EOFs), suppressing their influences on the damage detection process. Full article
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15 pages, 8403 KiB  
Article
Advancing Construction Efficiency through Geochemical Remediation: Limescale Management in Jet Grout-Driven Pumping Facilities
by No’am Zach Dvory and Yariv Tsafrir
Eng 2024, 5(2), 614-628; https://doi.org/10.3390/eng5020035 - 17 Apr 2024
Viewed by 349
Abstract
We address the challenges of limescale deposition and its management in urban construction sites, specifically within the Sumayil North project in Tel Aviv. Jet grouting, a method increasingly favored over conventional dewatering techniques for its minimal environmental impact and efficiency, is scrutinized for [...] Read more.
We address the challenges of limescale deposition and its management in urban construction sites, specifically within the Sumayil North project in Tel Aviv. Jet grouting, a method increasingly favored over conventional dewatering techniques for its minimal environmental impact and efficiency, is scrutinized for its unintended consequences on groundwater chemistry, particularly in relation to limescale formation. Our investigation centers on a dual approach: dissecting the geochemical dynamics leading to limescale deposition following jet grouting operations, and evaluating a remedial acid injection strategy implemented to counteract this phenomenon. We identify the critical factors influencing aquifer water chemistry through a detailed hydro-chemical analysis encompassing the Pleistocene Coastal Aquifer’s dynamics. The study reveals that the interaction between grout components and aquifer water significantly alters groundwater pH, driving the precipitation of calcium carbonate. The subsequent implementation of a sulfuric acid injection regimen successfully mitigated limescale accumulation, restoring pumping efficiency and neutralizing pH levels. We propose a workflow to manage and prevent limescale, emphasizing preemptive measures like custom grout compositions and controlled dewatering, with strict post-intervention groundwater monitoring. This approach balances operational efficiency, infrastructure integrity, and environmental stewardship in urban construction projects interfacing with sensitive aquifer systems. Full article
(This article belongs to the Section Chemical, Civil and Environmental Engineering)
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14 pages, 2886 KiB  
Article
Biofabrication of Silver Nanoparticles by Azadirachta indica Rhizosphere Bacteria with Enhanced Antibacterial Properties
by Mashhoor Kattali, Keerthana P. Mampett, Hamna Fathima Kodoor, Sreejesh Govindankutty Ponnenkunnathu, Somy Soman, Debarshi Kar Mahapatra, Tomy Muringayil Joseph, Józef Haponiuk and Sabu Thomas
Eng 2024, 5(2), 600-613; https://doi.org/10.3390/eng5020034 - 15 Apr 2024
Viewed by 1352
Abstract
Microorganisms (MOs) are prominent in ecological functioning and balance. The rhizosphere is considered one of the most diverse ecosystems on Earth and serves as a breeding spot for many MOs. Rhizosphere microbial diversity changes according to plant species, genotype, and the nature of [...] Read more.
Microorganisms (MOs) are prominent in ecological functioning and balance. The rhizosphere is considered one of the most diverse ecosystems on Earth and serves as a breeding spot for many MOs. Rhizosphere microbial diversity changes according to plant species, genotype, and the nature of the soil. The current study reports the possible use of bacteria isolated from the rhizosphere of Azadirachta indica for synthesizing silver nanoparticles (AgNPs). The physicochemical characterization and antibacterial activity of these green synthesized AgNPs are also reported. The gene (16S rRNA) sequence of bacteria isolated from the rhizosphere showed a maximum similarity of 99.25% with Bacillus subtilis. After incubation, the colorless reaction mixture transformed to brown, which indicates the formation of AgNPs, and UV-vis spectral analysis also confirmed the biosynthesis of AgNPs. Compared to lower temperatures, the efficiency of AgNP synthesis was high at the higher temperature. The scanning electron microscope image demonstrated spherical-shaped AgNPs with sizes ranging from 18 to 21 nm. Energy-dispersive X-ray analysis established the elemental analysis of synthesized AgNPs. The synthesized AgNPs showed strong bactericidal properties against pathogenic bacteria Klebsiella pneumonia, Pseudomonas aeruginosa, Escherichia coli, and methicillin-resistant Staphylococcus aureus. Full article
(This article belongs to the Section Materials Engineering)
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11 pages, 4369 KiB  
Article
Development of Highly Photoactive Mixed Metal Oxide (MMO) Based on the Thermal Decomposition of ZnAl-NO3-LDH
by Humaira Asghar, Valter Maurino and Muhammad Ahsan Iqbal
Eng 2024, 5(2), 589-599; https://doi.org/10.3390/eng5020033 - 11 Apr 2024
Viewed by 646
Abstract
The highly crystalline ZnAl layered double hydroxides (ZnAl-NO3-LDHs) are utilized for the potential transformation into mixed metal oxides (MMOs) through thermal decomposition and used further for the photodegradation of phenol to assess the influence of calcination on ZnAl-LDHs with enhanced photoactivity. [...] Read more.
The highly crystalline ZnAl layered double hydroxides (ZnAl-NO3-LDHs) are utilized for the potential transformation into mixed metal oxides (MMOs) through thermal decomposition and used further for the photodegradation of phenol to assess the influence of calcination on ZnAl-LDHs with enhanced photoactivity. The structure, composition, and morphological evolution of ZnAl-LDHs to ZnO-based MMO nanocomposites, which are composed of ZnO and ZnAl2O4, after calcination at different temperatures (400–600 °C), are all thoroughly examined in this work. The final ZnO and ZnAl2O4-based nanocomposites showed enhanced photocatalytic activity. The findings demonstrated that calcining ZnAl-LDHs from 400 to 600 °C increased the specific surface area and also enhanced the interlayer spacing of d003 while the transformation of LDHs into ZnO/ZnAl2O4 nanocomposites through calcining the ZnAl-LDH precursor at 600 °C showed significant photocatalytic properties, leading to complete mineralization of phenol under UV irradiation. Full article
(This article belongs to the Section Chemical, Civil and Environmental Engineering)
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23 pages, 31675 KiB  
Article
Enhancing Wear Resistance of Drilling Motor Components: A Tribological and Materials Application Study
by Achouak Benarbia, Olusegun Stanley Tomomewo, Aimen Laalam, Houdaifa Khalifa, Sarra Bertal and Kamel Abadli
Eng 2024, 5(2), 566-588; https://doi.org/10.3390/eng5020032 - 8 Apr 2024
Viewed by 508
Abstract
The oil and gas industry faces significant challenges due to wear on drilling motor components, such as thrust pins and inserts. These components are critical to the efficiency and reliability of drilling operations, yet are susceptible to wear, leading to significant economic losses, [...] Read more.
The oil and gas industry faces significant challenges due to wear on drilling motor components, such as thrust pins and inserts. These components are critical to the efficiency and reliability of drilling operations, yet are susceptible to wear, leading to significant economic losses, operational downtime, and safety risks. Despite previous research on wear-resistant materials and surface treatments, gaps exist in understanding the unique properties of thrust pins and inserts. The aim of this study is to enhance mechanical system performance by characterizing the wear resistance of these components. Through chemical analysis, hardness assessments, and metallographic examinations, the study seeks to identify specific alloys and microstructures conducive to wear resistance. Key findings reveal that AISI 9314 thrust pins exhibit superior wear resistance with a tempered martensite microstructure and a hardness of 41 HRc, whereas AISI 9310 inserts are less resistant, with a hardness of 35 HRc. The research employs advanced techniques, including a pin-on-disc tribometer, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and profilometry, to evaluate wear behavior, visualize wear patterns, analyze elemental composition, and quantify material loss and surface roughness. Our findings demonstrate that optimizing the material selection can significantly enhance the durability and efficiency of drilling motors. This has profound implications for the oil and gas industry, offering pathways to reduce maintenance costs, improve operational efficiency, and contribute to environmental sustainability by optimizing energy consumption and minimizing the carbon footprint of drilling operations. Full article
(This article belongs to the Section Materials Engineering)
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4 pages, 188 KiB  
Editorial
Special Issue: Feature Papers in Eng 2023
by Antonio Gil Bravo
Eng 2024, 5(2), 562-565; https://doi.org/10.3390/eng5020031 - 3 Apr 2024
Viewed by 832
Abstract
The aim of this third Eng Special Issue is to collect experimental and theoretical re-search relating to engineering science and technology [...] Full article
(This article belongs to the Special Issue Feature Papers in Eng 2023)
18 pages, 1686 KiB  
Article
Adaptive Control of Quadrotors in Uncertain Environments
by Daniel Leitão, Rita Cunha and João M. Lemos
Eng 2024, 5(2), 544-561; https://doi.org/10.3390/eng5020030 - 28 Mar 2024
Viewed by 475
Abstract
The problem addressed in this article consists of the motion control of a quadrotor affected by model disturbances and uncertainties. In order to tackle model uncertainty, adaptive control based on reinforcement learning is used. The distinctive feature of this article, in comparison with [...] Read more.
The problem addressed in this article consists of the motion control of a quadrotor affected by model disturbances and uncertainties. In order to tackle model uncertainty, adaptive control based on reinforcement learning is used. The distinctive feature of this article, in comparison with other works on quadrotor control using reinforcement learning, is the exploration of the underlying optimal control problem in which a quadratic cost and a linear dynamics allow for an algorithm that runs in real time. Instead of identifying a plant model, adaptation is obtained by approximating the performance index given by the Q-function using directional forgetting recursive least squares that rely on a linear regressor built from quadratic functions of input/output data. The adaptive algorithm proposed is tested in simulation in a cascade control structure that drives a quadrotor. Simulations show the improvement in performance that results when the proposed algorithm is turned on. Full article
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12 pages, 5756 KiB  
Article
Investigating Collaborative Robotic Assembly: A Case Study of the FANUC CRX-10 iA/L in Industrial Automation at i-Labs
by Albin Bajrami, Daniele Costa, Matteo Claudio Palpacelli and Federico Emiliani
Eng 2024, 5(2), 532-543; https://doi.org/10.3390/eng5020029 - 22 Mar 2024
Viewed by 596
Abstract
This study examines the practicality and limitations of using a FANUC CRX-10 iA/l collaborative robot to assemble a product component, highlighting the trade-offs between increased robotization and reduced manual intervention. Through a detailed case study in the i-Labs laboratory, critical factors affecting precision [...] Read more.
This study examines the practicality and limitations of using a FANUC CRX-10 iA/l collaborative robot to assemble a product component, highlighting the trade-offs between increased robotization and reduced manual intervention. Through a detailed case study in the i-Labs laboratory, critical factors affecting precision assembly such as station layout, tooling design and robot programming are discussed. The findings highlight the benefits of robots for nonstop operation, freeing up human operators for higher value tasks despite longer cycle times. In addition, the paper advocates further research into reliable gripping of small components, a current challenge for robotics. The work contributes to open science by sharing partial results and methods that could inform future problem solving in robotic assembly. Full article
(This article belongs to the Special Issue Feature Papers in Eng 2024)
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