Journal Description
Eng
Eng
is an international, peer-reviewed, open access journal on all areas of engineering, published quarterly online by MDPI.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within ESCI (Web of Science), Scopus, EBSCO and other databases.
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 18.7 days after submission; acceptance to publication is undertaken in 3.6 days (median values for papers published in this journal in the second half of 2023).
- Recognition of Reviewers: APC discount vouchers, optional signed peer review, and reviewer names published annually in the journal.
Latest Articles
Efficient Reduction of Carbon Tetrachloride in an Electrochemical Reactor with a Three-Dimensional Electrode
Eng 2024, 5(2), 983-991; https://doi.org/10.3390/eng5020054 - 26 May 2024
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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
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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.
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Open AccessArticle
Assessing the Suitability of Automation Using the Methods–Time–Measurement Basic System
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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
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
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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.
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(This article belongs to the Special Issue Feature Papers in Eng 2024)
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Open AccessArticle
Innovative Integration of Triboelectric Nanogenerators into Signature Stamps for Energy Harvesting, Self-Powered Electronic Devices, and Smart Applications
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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
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
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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.
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(This article belongs to the Section Electrical and Electronic Engineering)
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Open AccessArticle
NACA 2412 Drag Reduction Using V-Shaped Riblets
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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
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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.
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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.
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Open AccessArticle
Novel Synthesis of Nanocalcite from Phosphogypsum and Cesium Carbonate: Control and Optimization of Particle Size
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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 (registering DOI) - 21 May 2024
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
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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.
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(This article belongs to the Section Materials Engineering)
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Open AccessArticle
Process-Driven Layout Optimization of a Portable Hybrid Manufacturing Robotic Cell Structure
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Harry Bikas, Dimitrios Manitaras, Thanassis Souflas and Panagiotis Stavropoulos
Eng 2024, 5(2), 918-931; https://doi.org/10.3390/eng5020049 - 20 May 2024
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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
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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%.
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Open AccessArticle
An Efficient Approach for Damage Identification of Beams Using Mid-Span Static Deflection Changes
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Quoc-Bao Nguyen and Huu-Hue Nguyen
Eng 2024, 5(2), 895-917; https://doi.org/10.3390/eng5020048 - 20 May 2024
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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
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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.
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(This article belongs to the Section Chemical, Civil and Environmental Engineering)
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Open AccessArticle
Comparative Analysis of Finite Element Formulations for Simulating Hot Forming of Ti-6Al-4V Aerospace Components
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Olivier Pantalé, Sharan Raj Rangasamy Mahendren and Olivier Dalverny
Eng 2024, 5(2), 881-894; https://doi.org/10.3390/eng5020047 - 13 May 2024
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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
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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.
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(This article belongs to the Section Materials Engineering)
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Open AccessReview
Inertial Propulsion Devices: A Review
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Christopher G. Provatidis
Eng 2024, 5(2), 851-880; https://doi.org/10.3390/eng5020046 - 13 May 2024
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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
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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.
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Open AccessArticle
Influence of a Shaft Shoulder on the Torsional Load-Bearing Behaviour of Trochoidal Profile Contours as Positive Shaft–Hub Connections
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Masoud Ziaei, Marcus Selzer and Heiko Sommer
Eng 2024, 5(2), 834-850; https://doi.org/10.3390/eng5020045 - 11 May 2024
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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.
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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.
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Open AccessArticle
An Integrated Infrastructure Resilience Approach, from the Geotechnical Asset to the Transport Network
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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
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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
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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.
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Open AccessArticle
Minimum Shear Reinforcement for Reactive Powder Concrete Beams
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Hussein Kareem Sultan and Ghasan Fahim Huseien
Eng 2024, 5(2), 801-818; https://doi.org/10.3390/eng5020043 - 8 May 2024
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
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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.
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(This article belongs to the Special Issue Advances in Structural Analysis and Rehabilitation for Existing Structures)
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Open AccessReview
Automatic Reconstruction of 3D Models from 2D Drawings: A State-of-the-Art Review
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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
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
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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.
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(This article belongs to the Section Chemical, Civil and Environmental Engineering)
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Open AccessReview
Advancing Earth-Based Construction: A Comprehensive Review of Stabilization and Reinforcement Techniques for Adobe and Compressed Earth Blocks
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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
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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
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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.
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(This article belongs to the Section Chemical, Civil and Environmental Engineering)
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Open AccessArticle
Effects of Initial Small-Scale Material Nonlinearity on the Pre-Yield and Pre-Buckling Response of an Externally Pressurized Ring
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Reaz A. Chaudhuri and Deokjoo Kim
Eng 2024, 5(2), 733-749; https://doi.org/10.3390/eng5020040 - 30 Apr 2024
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
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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.
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(This article belongs to the Special Issue Feature Papers in Eng 2024)
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Open AccessArticle
Preliminary Envelope for Large Transport Aircrafts Operating with Non-Primary Fuels AVGAS, MOGAS and F76-Dieso
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José Luis Díaz Palencia
Eng 2024, 5(2), 720-732; https://doi.org/10.3390/eng5020039 - 28 Apr 2024
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,
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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.
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(This article belongs to the Section Chemical, Civil and Environmental Engineering)
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Open AccessReview
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
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,
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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.
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(This article belongs to the Special Issue Feature Papers in Eng 2024)
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Open AccessArticle
Numerical Analysis of Bearing Capacity in Deep Excavation Support Structures: A Comparative Study of Nailing Systems and Helical Anchors
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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
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
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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.
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(This article belongs to the Special Issue Feature Papers in Eng 2024)
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Open AccessArticle
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
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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
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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.
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Open AccessArticle
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
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
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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.
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(This article belongs to the Section Chemical, Civil and Environmental Engineering)
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