Eng | Special Issue : Feature Papers in Eng 2023

Editorial

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4 pages, 188 KiB

Open AccessEditorial

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 1264

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)

Research

Jump to: Editorial, Review

26 pages, 11831 KiB

Open AccessFeature PaperArticle

Self-Directed Mobile Robot Navigation Based on Functional Firefly Algorithm (FFA)

by Bhumeshwar K. Patle, Brijesh Patel, Alok Jha and Sunil Kumar Kashyap

Eng 2023, 4(4), 2656-2681; https://doi.org/10.3390/eng4040152 - 18 Oct 2023

Cited by 2 | Viewed by 1509

Abstract

This paper proposes an optimized mobile robot navigation strategy using a functional firefly algorithm (FFA) and choice function. This approach has two key advantages: first, the linear objective function performs efficiently with the single degree and finite-order polynomial time operation, and second, the [...] Read more.

This paper proposes an optimized mobile robot navigation strategy using a functional firefly algorithm (FFA) and choice function. This approach has two key advantages: first, the linear objective function performs efficiently with the single degree and finite-order polynomial time operation, and second, the cartesian constraint performs compactly with the chosen degree of freedom on the finite interval. This functional approach optimizes the size of operational parameters in context with key size, operation time, and a finite range of verification. The choice function achieves parameter order (size) reduction. The attraction characteristic of fireflies is represented by the choice function for optimizing the choice between low and high intensities of fireflies. In 2D and 3D environments, the proposed robot navigation performs well in an uncertain environment with static and dynamic obstacles. This efficiency includes the robot’s speed as determined by the choice function’s minimum path lengths. The collision-free path is achieved by the non-void family of non-void sets. The obtained results are optimal in terms of path length and navigational time. The proposed controller is also compared with the other existing controllers, and it is observed that the FFA gives the shortest path in less time for the same environmental condition. Full article

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14 pages, 3712 KiB

Open AccessArticle

Modelling Air Flow through Pneumatic Valves: A Brief Review with an Experimental Case Study

by Gustavo Koury Costa

Eng 2023, 4(4), 2601-2614; https://doi.org/10.3390/eng4040149 - 16 Oct 2023

Viewed by 1965

Abstract

Compressible flow models are commonly used for describing air flow through pneumatic valves. Because of the difficulties in predicting viscous losses, these models ultimately rely on experimental determination of coefficients. Different equations have been proposed for different fluid speeds, having the sonic fluid [...] Read more.

Compressible flow models are commonly used for describing air flow through pneumatic valves. Because of the difficulties in predicting viscous losses, these models ultimately rely on experimental determination of coefficients. Different equations have been proposed for different fluid speeds, having the sonic fluid velocity as a reference mark. However, one might question whether a much simpler approach, where the fluid is considered as incompressible, would still give good results within the typical range of industrial applications. Moreover, practically all models presuppose that the valve output pressure decreases in time, as in a discharge process. This paper reviews some representative one-dimensional compressible flow models and discusses the appropriateness of using equations based solely on discharging flows. Two experimental circuits, where an air reservoir is pressurized and, subsequently, decompressed, are used for comparison between different flow models. It is shown that a simpler set of equations still produces acceptable results for practical pneumatic applications. Full article

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19 pages, 7367 KiB

Open AccessFeature PaperArticle

Comparison of Three Linear Digital Filters Applied to Improve the Quality of the Measured Acoustic Field

by Estevão Patricio Rodrigues, Djalma Simões dos Santos and Flávio Buiochi

Eng 2023, 4(4), 2582-2600; https://doi.org/10.3390/eng4040148 - 16 Oct 2023

Viewed by 1316

Abstract

The measurement of acoustic fields generated by ultrasonic transducers is important for determining the focal length, lateral resolution, and amplitudes of the lateral and grating lobes. The acoustic field is commonly characterized by a set of scans using a needle hydrophone. The output [...] Read more.

The measurement of acoustic fields generated by ultrasonic transducers is important for determining the focal length, lateral resolution, and amplitudes of the lateral and grating lobes. The acoustic field is commonly characterized by a set of scans using a needle hydrophone. The output of the hydrophone can be connected to an analog filter to enhance the signal. However, the analog filter might not be sufficient to avoid the noises that distort the signals. Alternatively, linear digital filters can be advantageous to improving the acoustic-field characterization. In this work, three filters were investigated: moving average (MA), band-pass Hamming window (HW), and band-pass Blackman window (BW). The filters were implemented and evaluated in terms of the root-mean-square error (RMSE) of the measured sound field, which was filtered, in relation to the simulated acoustic field (gold standard). As a compromise between effective filtering and signal non-distortion, a method to model the MA kernel length was proposed. All the filters reduced the noise of the measured acoustic field. The HW and the BW filters were more effective (RMSE = 4.01%) than the MA filter (RMSE = 4.28%). In spite of the small quantitative difference, acoustic field comparisons showed qualitative improvements. Full article

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18 pages, 5289 KiB

Open AccessArticle

Development of an Airbag Geometry Specific for Autonomous Vehicles

by Bartolomeu Franco, José Manuel Alves Ribeiro and Isidro de Jesús Sánchez-Arce

Eng 2023, 4(4), 2553-2570; https://doi.org/10.3390/eng4040146 - 11 Oct 2023

Viewed by 2034

Abstract

Airbags are important safety devices in modern vehicles. However, their effectiveness is linked to the occupants being seated in standard positions. Although autonomous vehicles are less accident-prone, they are also equipped with airbags, similar to any other vehicle. Additionally, autonomous vehicles allow for [...] Read more.

Airbags are important safety devices in modern vehicles. However, their effectiveness is linked to the occupants being seated in standard positions. Although autonomous vehicles are less accident-prone, they are also equipped with airbags, similar to any other vehicle. Additionally, autonomous vehicles allow for occupants seated in non-standard positions, so in the case of a collision, the airbags’ effectiveness decreases. In this work, an airbag design suitable for both assisted and autonomous driving conditions is proposed, the driver’s airbag being the object of interest. Airbag geometry, threads, seam strength, and seam geometries were selected following Design of Experiments (DoE) methodologies and a series of experimental tests. Moreover, an adaptive system based on sewn tethers allows the airbag to adapt to the driving mode, which is proposed and validated. Finally, all the findings were experimentally tested on two different geometries. The results were satisfactory as the deployed airbag shape and dimensions were as expected, indicating that this airbag design is capable of protecting the driver of a vehicle capable of autonomous driving. Full article

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11 pages, 8005 KiB

Open AccessFeature PaperArticle

Robot Cooking—Transferring Observations into a Planning Language: An Automated Approach in the Field of Cooking

by Markus Schmitz, Florian Menz, Ruben Grunau, Nils Mandischer, Mathias Hüsing and Burkhard Corves

Eng 2023, 4(4), 2514-2524; https://doi.org/10.3390/eng4040143 - 7 Oct 2023

Viewed by 1465

Abstract

The recognition of human activities from video sequences and their transformation into a machine-readable form is a challenging task, which is the subject of many studies. The goal of this project is to develop an automated method for analyzing, identifying and processing motion [...] Read more.

The recognition of human activities from video sequences and their transformation into a machine-readable form is a challenging task, which is the subject of many studies. The goal of this project is to develop an automated method for analyzing, identifying and processing motion capture data into a planning language. This is performed in a cooking scenario by recording the pose of the acting hand. First, predefined side actions are detected in the dataset using classification. The remaining frames are then clustered into main actions. Using this information, the known initial positions and virtual object tracking, a machine-readable planning domain definition language (PDDL) is generated. Full article

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15 pages, 4997 KiB

Open AccessFeature PaperArticle

Comparative Study of Musical Timbral Variations: Crescendo and Vibrato Using FFT-Acoustic Descriptor

by Yubiry Gonzalez and Ronaldo C. Prati

Eng 2023, 4(3), 2468-2482; https://doi.org/10.3390/eng4030140 - 21 Sep 2023

Cited by 1 | Viewed by 1178

Abstract

A quantitative evaluation of the musical timbre and its variations is important for the analysis of audio recordings and computer-aided music composition. Using the FFT acoustic descriptors and their representation in an abstract timbral space, variations in a sample of monophonic sounds of [...] Read more.

A quantitative evaluation of the musical timbre and its variations is important for the analysis of audio recordings and computer-aided music composition. Using the FFT acoustic descriptors and their representation in an abstract timbral space, variations in a sample of monophonic sounds of chordophones (violin, cello) and aerophones (trumpet, transverse flute, and clarinet) sounds are analyzed. It is concluded that the FFT acoustic descriptors allow us to distinguish the timbral variations in the musical dynamics, including crescendo and vibrato. Furthermore, using the Random Forest algorithm, it is shown that the FFT-Acoustic provides a statistically significant classification to distinguish musical instruments, families of instruments, and dynamics. We observed an improvement in the FFT-Acoustic descriptors when classifying pitch compared to some timbral features of Librosa. Full article

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11 pages, 1951 KiB

Open AccessFeature PaperArticle

Setup Time Reduction of an Automotive Parts Assembly Line Using Lean Tools and Quality Tools

by Cátia Oliveira and Tânia M. Lima

Eng 2023, 4(3), 2352-2362; https://doi.org/10.3390/eng4030134 - 13 Sep 2023

Cited by 2 | Viewed by 2529

Abstract

The business world is becoming more competitive. Therefore, it is crucial to increase the flexibility of production by decreasing the time used in the processes of preparing the production lines for new items’ production, reducing changeover and setup times. This paper presents a [...] Read more.

The business world is becoming more competitive. Therefore, it is crucial to increase the flexibility of production by decreasing the time used in the processes of preparing the production lines for new items’ production, reducing changeover and setup times. This paper presents a case study where the main goal is to reduce the setup time of welding robots. Single Minute Exchange of Die (SMED) was implemented, using other tools such as the Spaghetti Diagram, ERCS Analysis (Eliminate, Rearrange, Combine, Simplify), Gemba Walk, Standardized Work, Flowcharts, and Pareto Diagram. The setup time decreased by 36% in the welding robots studied, decreasing the motions by 43% during the changeover process and reducing the time from the categories: “transportation”, “main”, “other”, and “waiting”. In addition to SMED implementation, this study offers an integrated study of several Lean tools and Quality tools to achieve the maximum reduction of changeover and setup times. Full article

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27 pages, 7844 KiB

Open AccessFeature PaperArticle

Power Transmission Using Circular Elements Bounded by Given Central Angle in Rolling Contact

by Christopher G. Provatidis

Eng 2023, 4(3), 2309-2335; https://doi.org/10.3390/eng4030132 - 11 Sep 2023

Viewed by 2665

Abstract

In the present study, the concept of utilizing two circular cam-track disks, of the same central angle, in combination with one circular roller is presented. The roller is restrained to move within a vertical groove, and at the same time it rotates with [...] Read more.

In the present study, the concept of utilizing two circular cam-track disks, of the same central angle, in combination with one circular roller is presented. The roller is restrained to move within a vertical groove, and at the same time it rotates with rolling-contact on both cam tracks. When the upper cam is fully travelled by the roller, the same occurs with the lower one, despite their different lengths. Therefore, during the rolling contact, the two cams always sweep the same central angle. The aforementioned configuration of the two circular arcs may be considered as a unit cell, which can be repeated an even number of times, and when folded forms a closed circular groove between two cam-track disks. For better understanding, a manufactured prototype and 3D CAD-models have been developed. The operation of this setup as a gearless automotive differential is demonstrated by performing two bench experiments, which are then explained by a simplified mechanical model. The latter focuses on the implementation of the principle of the inclined plane, in which an upper limit of the inclination angle is imposed in accordance with the coefficient of friction at the friction disks. Previous patents on gearless differentials are discussed and other possible applications in mechanical engineering are outlined. Full article

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13 pages, 2860 KiB

Open AccessArticle

Assessment of Techniques for Detection of Transient Radio-Frequency Interference (RFI) Signals: A Case Study of a Transient in Radar Test Data

by Stephen L. Durden, Victor A. Vilnrotter and Scott J. Shaffer

Eng 2023, 4(3), 2191-2203; https://doi.org/10.3390/eng4030126 - 21 Aug 2023

Cited by 1 | Viewed by 1342

Abstract

The authors present a case study of the investigation of a transient signal that appeared in the testing of a radar receiver. The characteristics of the test conditions and data are first discussed. The authors then proceed to outline the methods for detecting [...] Read more.

The authors present a case study of the investigation of a transient signal that appeared in the testing of a radar receiver. The characteristics of the test conditions and data are first discussed. The authors then proceed to outline the methods for detecting and analyzing transients in the data. For this, they consider several methods based on modern signal processing and evaluate their utility. The initial method used for identifying transients is based on computer vision techniques, specifically, thresholding spectrograms into binary images, morphological processing, and object boundary extraction. The authors also consider deep learning methods and methods related to optimal statistical detection. For the latter approach, since the transient in this case was chirp-like, the method of maximum likelihood is used to estimate its parameters. Each approach is evaluated, followed by a discussion of how the results could be extended to analysis and detection of other types of transient radio-frequency interference (RFI). The authors find that computer vision, deep learning, and statistical detection methods are all useful. However, each is best used at different stages of the investigation when a transient appears in data. Computer vision is particularly useful when little is known about the transient, while traditional statistically optimal detection can be quite accurate once the structure of the transient is known and its parameters estimated. Full article

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11 pages, 2144 KiB

Open AccessArticle

Cold Plasma Technology for Tomato Processing By-Product Valorization: The Case of Tomato Peeling and Peel Drying

by Maxim Sosnin, Egor Berestenko, Emad H. A. Mounassar and Ivan Shorstkii

Eng 2023, 4(3), 2167-2177; https://doi.org/10.3390/eng4030124 - 15 Aug 2023

Cited by 3 | Viewed by 1664

Abstract

The tomato processing industry is focused on product yield maximization, keeping energy costs and waste effluents to a minimum while maintaining high product quality. In our study, cold atmospheric plasma (CAP) pretreatment enhanced tomato processing to facilitate peelability, a specific peeling process, and [...] Read more.

The tomato processing industry is focused on product yield maximization, keeping energy costs and waste effluents to a minimum while maintaining high product quality. In our study, cold atmospheric plasma (CAP) pretreatment enhanced tomato processing to facilitate peelability, a specific peeling process, and enhance peel drying. Peeling force analysis determined that CAP pretreatment of whole tomatoes improved peelability under the conditions used. The specific peeling force after CAP treatment decreased by more than three times. It was observed that cold atmospheric plasma pretreatment reduced the duration of infrared drying of tomato peels by 18.2%. Along with that, a positive effect on the reduction of the specific energy consumption of peel drying was shown for CAP-pretreated tomato peels. The obtained data show that the technology of cold atmospheric plasma pretreatment, in particular, when processing whole tomatoes and tomato peels, has a promising application in industry, as it can significantly reduce the specific energy consumption for peeling and drying procedures. Full article

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10 pages, 29410 KiB

Open AccessFeature PaperArticle

Automatic Identification of Corrosion in Marine Vessels Using Decision-Tree Imaging Hierarchies

by Georgios Chliveros, Stylianos V. Kontomaris and Apostolos Letsios

Eng 2023, 4(3), 2090-2099; https://doi.org/10.3390/eng4030118 - 26 Jul 2023

Cited by 4 | Viewed by 1802

Abstract

We propose an unsupervised method for eigen tree hierarchies and quantisation group association for segmentation of corrosion in marine vessel hull inspection via camera images. Our unsupervised approach produces image segments that are examined to decide on defect recognition. The method generates a [...] Read more.

We propose an unsupervised method for eigen tree hierarchies and quantisation group association for segmentation of corrosion in marine vessel hull inspection via camera images. Our unsupervised approach produces image segments that are examined to decide on defect recognition. The method generates a binary decision tree, which, by means of bottom-up pruning, is revised, and dominant leaf nodes predict the areas of interest. Our method is compared with other techniques, and the results indicate that it achieves better performance for true- vs. false-positive area against ideal (ground truth) coverage. Full article

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12 pages, 5257 KiB

Open AccessFeature PaperArticle

Microsimulation Modelling and Scenario Analysis of a Congested Abu Dhabi Highway

by Umair Hasan, Hamad AlJassmi and Aisha Hasan

Eng 2023, 4(3), 2003-2014; https://doi.org/10.3390/eng4030113 - 17 Jul 2023

Cited by 3 | Viewed by 2079

Abstract

Today’s roadways are subject to traffic congestion, the deterioration of surface-assets (often due to the overreliance on private vehicle traffic), increasing vehicle-operation and fuel costs, and pollutant emissions. In Abu Dhabi, private car traffic forms the major share on urban highways, as the [...] Read more.

Today’s roadways are subject to traffic congestion, the deterioration of surface-assets (often due to the overreliance on private vehicle traffic), increasing vehicle-operation and fuel costs, and pollutant emissions. In Abu Dhabi, private car traffic forms the major share on urban highways, as the infrastructure was built to a high quality and the public transport network needs expansion, resulting in traffic congestion on major highways. These issues are arguably addressable by appropriate decisions at the planning stage. Microsimulation modeling of driving behavior in Abu Dhabi is presented for empirical assessment of traffic management scenarios. This paper presents a technique for developing, calibrating, validating, and the scenario analysis of a detailed VISSIM-based microsimulation model of a 3.5 km section of a 5-lane divided highway in Abu Dhabi. Traffic-count data collected from two sources, i.e., the local transport department (year 2007) and municipality (2007 and 2015–2016) were used. Gaps in traffic-counts between ramps and the highway mainline were noted, which is a common occurrence in real-world data situations. A composite dataset for a representative week in 2015 was constructed, and the model was calibrated and validated with a 15% (<100 vehicles per hour) margin of error. Scenario analysis of a potential public bus transport service operating at 15 min headway and 40% capacity was assessed against the base case, for a 2015–2020 projected period. The results showed a significant capacity enhancement and improvement in the traffic flow. A reduction in the variation between vehicle travel times was observed for the bus-based scenario, as less bottlenecking and congestion were noted for automobiles in the mainline segments. The developed model could be used for further scenario analyses, to find optimized traffic management strategies over the highway’s lifecycle, whereas it could also be used for similar evaluations of other major roads in Abu Dhabi post-calibration. Full article

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22 pages, 2584 KiB

Open AccessArticle

Redesign of a Failed Hoisting Shaft of a Vertical Transfer Device

by Filipe Alexandre Couto da Silva and Paulo M. S. T. de Castro

Eng 2023, 4(3), 1981-2002; https://doi.org/10.3390/eng4030112 - 14 Jul 2023

Viewed by 2073

Abstract

The redesign of a failed hoisting shaft belonging to a 10 m stroke vertical transfer device (VTD) is presented. Firstly, the operation of the VTD is thoroughly analysed, the variation of loads and moments along the operating cycle is characterised, and transients such [...] Read more.

The redesign of a failed hoisting shaft belonging to a 10 m stroke vertical transfer device (VTD) is presented. Firstly, the operation of the VTD is thoroughly analysed, the variation of loads and moments along the operating cycle is characterised, and transients such as emergency stop loads are calculated. The selection of safety factors and duty cycle factors was followed by the shaft sizing. After an initial rough sizing, the high-cycle fatigue (HCF) design for cyclic bending moments was performed, first considering constant torque and then considering cyclic torque. The number of bending and torsion cycles performed by the hoisting shaft over 10 years was shown to exceed 10⁶, and an infinite life design is mandatory. The analyses showed that the initial shaft diameter was insufficient, thus justifying the failures observed before the present redesign. A classical fatigue model combining torsional shear stresses with bending stresses was used to take into account reversed torsional loading and ensure infinite fatigue life. This work highlights the need to thoroughly understand a machine’s operating cycle so that the wrong premises for fatigue design calculations are not assumed. Full article

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12 pages, 3787 KiB

Open AccessArticle

The Learning Curve of People with Complete Spinal Cord Injury Using a NES_s-FES_s Interface in the Sitting Position: Pilot Study

by Felipe Augusto Fiorin, Larissa Gomes Sartori, María Verónica González Méndez, Christiane Henriques Ferreira, Maria Bernadete de Morais França and Eddy Krueger

Eng 2023, 4(2), 1711-1722; https://doi.org/10.3390/eng4020097 - 17 Jun 2023

Viewed by 1154

Abstract

The use of assistive technologies, such as a non-invasive interface for neuroelectrical signal and functional electrical stimulation (NES

_{s}

-FES

_{s}

), can mitigate the effects of spinal cord injury (SCI), including impairment of motor, sensory, and autonomic functions. However, it requires an [...] Read more.

The use of assistive technologies, such as a non-invasive interface for neuroelectrical signal and functional electrical stimulation (NES

_{s}

-FES

_{s}

), can mitigate the effects of spinal cord injury (SCI), including impairment of motor, sensory, and autonomic functions. However, it requires an adaptation process to enhance the user’s performance by tuning the learning curve to a point of extreme relevance. Therefore, in this pilot study, the learning curves of two people with complete SCI (

P_{A}

: paraplegic-T

_{6}

, and

P_{B}

: quadriplegic-C

_{4}

) were analyzed, with results obtained on the accuracy of the classifier (Ac

_{C S P - L D A}

), repetitions of intra-day training, and number of hits and misses in the activation of FES

_{s}

for sixteen interventions using the NES

_{s}

-FES

_{s}

interface. We assumed that the data were non-parametric and performed the Spearman’s

ρ

test (and p-value) for correlations between the data. There was variation between the learning curves resulting from the training of the NES

_{s}

-FES

_{s}

interface for the two participants, and the variation was influenced by factors both related and unrelated to the individual users. Regardless of these factors,

P_{A}

improved significantly in its learning curve, as it presented lower values in all variables in the first interventions compared to the

P_{B}

, although only

P_{A}

showed statistical correlation (on Ac

_{C S P - L D A}

values in RLL). It was concluded that despite the variations according to factors intrinsic to the user and the functioning of the equipment used, sixteen interventions were sufficient to achieve a good learning effect to control the NES

_{s}

-FES

_{s}

interface. Full article

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29 pages, 2910 KiB

Open AccessFeature PaperArticle

A Limited-Scope Probabilistic Risk Assessment Study to Risk-Inform the Design of a Fuel Storage System for Spent Pebble-Filled Dry Casks

by Joomyung Lee, Havva Tayfur, Mostafa M. Hamza, Yahya A. Alzahrani and Mihai A. Diaconeasa

Eng 2023, 4(2), 1655-1683; https://doi.org/10.3390/eng4020094 - 8 Jun 2023

Viewed by 1655

Abstract

This limited-scope study demonstrates the application of probabilistic risk assessment (PRA) methodologies to a spent fuel storage system for spent pebble-filled dry cask with a focus only on the necessary PRA technical elements sufficient to risk-inform the spent fuel storage system design. A [...] Read more.

This limited-scope study demonstrates the application of probabilistic risk assessment (PRA) methodologies to a spent fuel storage system for spent pebble-filled dry cask with a focus only on the necessary PRA technical elements sufficient to risk-inform the spent fuel storage system design. A dropping canister scenario in a silo of the spent fuel storage system is analyzed through an initiating event (IE) identification from the Master Logic Diagram (MLD); event sequence analysis (ES) by establishing the event tree; data analysis (DA) for event sequence quantification (ESQ) with uncertainty quantification; mechanistic source term (MST) analysis by using ORIGEN; radiological consequence analysis (RC) by deploying MicroShield, and risk integration (RI) by showing the Frequency-Consequence (F-C) target curve in the emergency area boundary (EAB). Additionally, a sensitivity study is conducted using the ordinary least square (OLS) regression method to assess the impact of variables such as failed pebble numbers, their location in the canister, and building wall thickness. Furthermore, the release categories grouped from the end states in the event tree are verified as safety cases through the F-C curve. This study highlights the implementation of PRA elements in a logical and structured manner, using appropriate methodologies and computational tools, thereby showing how to risk-inform the design of a dry cask system for storing spent pebble-filled fuel. Full article

(This article belongs to the Special Issue Feature Papers in Eng 2023)

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19 pages, 9843 KiB

Open AccessArticle

A Deep Learning-Based Visual Map Generation for Mobile Robot Navigation

by Carlos A. García-Pintos, Noé G. Aldana-Murillo, Emmanuel Ovalle-Magallanes and Edgar Martínez

Eng 2023, 4(2), 1616-1634; https://doi.org/10.3390/eng4020092 - 6 Jun 2023

Cited by 2 | Viewed by 2098

Abstract

Visual map-based robot navigation is a strategy that only uses the robot vision system, involving four fundamental stages: learning or mapping, localization, planning, and navigation. Therefore, it is paramount to model the environment optimally to perform the aforementioned stages. In this paper, we [...] Read more.

Visual map-based robot navigation is a strategy that only uses the robot vision system, involving four fundamental stages: learning or mapping, localization, planning, and navigation. Therefore, it is paramount to model the environment optimally to perform the aforementioned stages. In this paper, we propose a novel framework to generate a visual map for environments both indoors and outdoors. The visual map comprises key images sharing visual information between consecutive key images. This learning stage employs a pre-trained local feature transformer (LoFTR) constrained with a 3D projective transformation (a fundamental matrix) between two consecutive key images. Outliers are efficiently detected using marginalizing sample consensus (MAGSAC) while estimating the fundamental matrix. We conducted extensive experiments to validate our approach in six different datasets and compare its performance against hand-crafted methods. Full article

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31 pages, 3369 KiB

Open AccessArticle

An Overview of Smart Materials and Technologies for Concrete Construction in Cold Weather

by Jonny Nilimaa and Vasiola Zhaka

Eng 2023, 4(2), 1550-1580; https://doi.org/10.3390/eng4020089 - 31 May 2023

Cited by 16 | Viewed by 6210

Abstract

Cold weather conditions pose significant challenges to the performance and durability of concrete materials, construction processes, and structures. This paper aims to provide a comprehensive overview of the material-related challenges in cold weather concrete construction, including slow setting, reduced curing rate, and slower [...] Read more.

Cold weather conditions pose significant challenges to the performance and durability of concrete materials, construction processes, and structures. This paper aims to provide a comprehensive overview of the material-related challenges in cold weather concrete construction, including slow setting, reduced curing rate, and slower strength development, as well as frost damage, early freezing, and freeze–thaw actions. Various innovative materials and technologies may be implemented to address these challenges, such as optimizing the concrete mix proportions, chemical admixtures, supplementary cementitious materials, and advanced construction techniques. The paper also examines the impact of weather-related challenges for personnel, equipment, and machinery in cold environments and highlights the importance of effective planning, communication, and management strategies. Results indicate that the successful implementation of appropriate strategies can mitigate the challenges, reduce construction time, and enhance the performance, durability, and sustainability of concrete structures in cold and freezing temperatures. The paper emphasizes the importance of staying updated about the latest advancements and best practices in the field. Future trends include the development of smart and functional concrete materials, advanced manufacturing and construction techniques, integrated design, and optimization of tools, all with a strong focus on sustainability and resilience. Full article

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19 pages, 6112 KiB

Open AccessArticle

A Comparison of Personalized and Generalized LSTM Neural Networks for Deriving VCG from 12-Lead ECG

by Prashanth Shyam Kumar, Mouli Ramasamy and Vijay K. Varadan

Eng 2023, 4(2), 1337-1355; https://doi.org/10.3390/eng4020078 - 10 May 2023

Cited by 1 | Viewed by 1554

Abstract

Vectorcardiography (VCG) is a valuable diagnostic tool that complements the standard 12-lead ECG by offering additional spatiotemporal information to clinicians. However, due to the need for additional measurement hardware and too many electrodes in a clinical scenario if performed along with a standard [...] Read more.

Vectorcardiography (VCG) is a valuable diagnostic tool that complements the standard 12-lead ECG by offering additional spatiotemporal information to clinicians. However, due to the need for additional measurement hardware and too many electrodes in a clinical scenario if performed along with a standard 12-lead, there is a need to find methods to derive the VCG from the ECG. We have evaluated the use of Long Short-term Memory (LSTM) neural networks to learn the transformation from 12-lead ECG to VCG that is applicable across subjects and for each subject. We refer to these networks as generalized and personalized, respectively. We calculated the Root Mean Square Error (RMSE), R², and Pearson correlation coefficient to compare waveforms of derived and actual VCG. We also extracted and compared diagnostic parameters from VCG, namely the QRS-loop magnitude, T-loop magnitude, and QRS-T spatial angle, from actual and derived VCGs using the Pearson correlation coefficient and Bland Altman limits of agreement. The personalized models performed better than generalized models in waveform comparisons and in the error of extracted diagnostic parameters from VCG waveforms. The use of personalized transformations for the derivation of VCG from standard 12-lead has the potential to improve and augment the diagnostic yield and accuracy of a standard 12-lead interpretation. Full article

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14 pages, 1029 KiB

Open AccessFeature PaperArticle

Pressure Anomalies Beneath Solitary Waves with Constant Vorticity

by Marcelo V. Flamarion, Eduardo M. Castro and Roberto Ribeiro-Jr

Eng 2023, 4(2), 1306-1319; https://doi.org/10.3390/eng4020076 - 27 Apr 2023

Cited by 3 | Viewed by 1168

Abstract

While some studies have investigated the particle trajectories and stagnation points beneath solitary waves with constant vorticity, little is known about the pressure beneath such waves. To address this gap, we investigate numerically the pressure beneath solitary waves in flows with constant vorticity. [...] Read more.

While some studies have investigated the particle trajectories and stagnation points beneath solitary waves with constant vorticity, little is known about the pressure beneath such waves. To address this gap, we investigate numerically the pressure beneath solitary waves in flows with constant vorticity. Through a conformal mapping that flats the physical domain, we develop a numerical approach that allows us to compute the pressure and the velocity field in the fluid domain. Our experiments indicate that there exists a threshold vorticity such that pressure anomalies and stagnation points occur when the intensity of the vorticity is greater than this threshold. Above this threshold, the pressure on the bottom boundary has two points of local maxima and there are three stagnation points in the flow, and below it the pressure has one local maximum and there is no stagnation point. Full article

(This article belongs to the Special Issue Feature Papers in Eng 2023)

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29 pages, 12116 KiB

Open AccessFeature PaperArticle

A Numerical Study on the Response of a Very Large Floating Airport to Airplane Movement

by Taro Kakinuma and Masaki Hisada

Eng 2023, 4(2), 1236-1264; https://doi.org/10.3390/eng4020073 - 21 Apr 2023

Cited by 2 | Viewed by 2427

Abstract

Numerical simulations were generated to investigate the response of a floating airport to airplane movement using the nonlinear shallow water equations of velocity potential for water waves interacting with a floating thin plate. First, in the 1D calculations, the airplanes were B747 and [...] Read more.

Numerical simulations were generated to investigate the response of a floating airport to airplane movement using the nonlinear shallow water equations of velocity potential for water waves interacting with a floating thin plate. First, in the 1D calculations, the airplanes were B747 and B737. At touch-and-go, when the airplane speed is closer to the water wave speed, even B737 produced large waves based on the resonance. The impacts due to both the touchdown and leaving of the airplanes generated other forward and backward waves. At landing, when the airplane speed approached the water wave speed, a forced wave was generated and amplified, with many free waves ahead. At takeoff, a wave clump, generated shortly after starting to run, propagated in front of the airplanes. Although the wave height increased from superposition with the reflected waves, the wave reflectance was reduced by lowering the flexural rigidity near the airport edge. Second, in the 2D calculations, B787 performed landing and takeoff. When the still water depth is shallower, a grid-like pattern was formed at the floating airport and appeared more remarkably in landing than in takeoff. The effective amplification occurred from a sufficient load applied when the airplane speed approached the water wave speed. Furthermore, the maximum upslope gradient beneath the airplane increased as the still water depth decreased, and it was larger in takeoff than in landing. Full article

(This article belongs to the Special Issue Feature Papers in Eng 2023)

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12 pages, 2284 KiB

Open AccessFeature PaperArticle

Rapid Prediction of Leaf Water Content in Eucalypt Leaves Using a Handheld NIRS Instrument

by Joel B. Johnson

Eng 2023, 4(2), 1198-1209; https://doi.org/10.3390/eng4020070 - 19 Apr 2023

Cited by 2 | Viewed by 1619

Abstract

Leaf water content (LWC) is a crucial physiological parameter that plays a limiting role in the efficiency of photosynthesis and biomass production in many plants. This study investigated the use of diffuse reflectance near-infrared spectroscopy (NIRS) for the rapid prediction of the gravimetric [...] Read more.

Leaf water content (LWC) is a crucial physiological parameter that plays a limiting role in the efficiency of photosynthesis and biomass production in many plants. This study investigated the use of diffuse reflectance near-infrared spectroscopy (NIRS) for the rapid prediction of the gravimetric LWC in eucalypt leaves from Eucalyptus and Corymbia genera. The best-performing model for LWC gave a R²_pred of 0.85 and RMSEP of 2.32% for an independent test set, indicating that the handheld NIR instrument could predict the LWC with a high level of accuracy. The use of support vector regression gave slightly more accurate results compared with partial least squares regression. Prediction models were also developed for leaf thickness, although these were somewhat less accurate (R²_pred of 0.58; RMSEP of 2.7 µm). Nevertheless, the results suggest that handheld NIR instruments may be useful for in-field screening of LWC and leaf thickness in Australian eucalypt species. As an example of its use, the NIR method was applied for rapid analysis of the LWC and leaf thickness of every leaf found on an E. populnea sapling. Full article

(This article belongs to the Special Issue Feature Papers in Eng 2023)

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19 pages, 5547 KiB

Open AccessFeature PaperArticle

Microservice-Oriented Architecture for Industry 4.0

by Ricardo Pasquati Pontarolli, Jeferson André Bigheti, Lucas Borges Rodrigues de Sá and Eduardo Paciencia Godoy

Eng 2023, 4(2), 1179-1197; https://doi.org/10.3390/eng4020069 - 19 Apr 2023

Cited by 10 | Viewed by 3760

Abstract

Industry 4.0 (I4.0) is characterized by the integration of digital technologies into manufacturing processes and highlights new requirements for industrial systems such as greater interoperability, decentralization, modularization, and independence. The traditional hierarchical architecture of Industrial Automation Systems (IAS) does not fulfill these requirements [...] Read more.

Industry 4.0 (I4.0) is characterized by the integration of digital technologies into manufacturing processes and highlights new requirements for industrial systems such as greater interoperability, decentralization, modularization, and independence. The traditional hierarchical architecture of Industrial Automation Systems (IAS) does not fulfill these requirements and is evolving to incorporate information technologies in order to support I4.0 applications. The integration among these technologies, equipment, and systems at different industry levels requires a migration from the legacy vertical architecture to a flat architecture based on services. Service-oriented architecture (SOA) and, more recently, microservices play a critical role in I4.0 by providing a framework for integrating complex systems and meeting those requirements. This paper presents the development of a Microservice-Oriented Architecture for Industry 4.0 (MOAI), initially focused on evolving IAS to the I4.0. The objective is to describe the development, deployment, and testing of an IAS architecture based on microservices prepared for I4.0 applications. On the contrary to developing the whole software for the industrial SOA, the MOAI was developed on top of the Moleculer framework, which allowed focusing on creating services and applications for the automation and process control industry context. The development of several microservices and security mechanisms for the MOAI is presented, as is the deployment of IAS applications as services such as process control, SCADA, discrete automation, among others. The MOAI was implemented in a process control pilot plant for experimentation. Experimental results of the MOAI for IAS applications are investigated, the microservice communication performance is evaluated, and the pros and cons of microservices for I4.0 are discussed. Full article

(This article belongs to the Special Issue Feature Papers in Eng 2023)

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12 pages, 7247 KiB

Open AccessArticle

Are Implant Threads Important for Implant Stability? An In Vitro Study Using Low-Density Polyurethane Sheets

by Luca Comuzzi, Margherita Tumedei, Natalia Di Pietro, Tea Romasco, Lorenzo Montesani, Adriano Piattelli and Ugo Covani

Eng 2023, 4(2), 1167-1178; https://doi.org/10.3390/eng4020068 - 19 Apr 2023

Cited by 4 | Viewed by 1585

Abstract

Different strategies are known to improve implant primary stability (PS) and the bone-to-implant contact in post-extractive conditions, such as the macro-geometry of screws and apical threads, which can enhance the mechanical characteristics. In any case, the role of the apical area design in [...] Read more.

Different strategies are known to improve implant primary stability (PS) and the bone-to-implant contact in post-extractive conditions, such as the macro-geometry of screws and apical threads, which can enhance the mechanical characteristics. In any case, the role of the apical area design in maintaining or improving the PS, especially in low-quality bone, still remains unclear. Thus, the present study aimed at evaluating in vitro the Insertion Torque (IT), Removal Torque (RT), and Resonance Frequency Analysis (RFA) of different implant apical threads in a cylindrical (EE) and in three conical implants (T3, TAC, Intra-lock) inserted in simulated post-extraction conditions on low-density polyurethane foams of 10 and 20 pounds per cubic foot (PCF), with and without the addition of a cortical sheet of 30 PCF in density. The IT, RT, and RFA values of all the implants tested were directly proportional to the polyurethane density and to the presence of the cortical sheet, but TAC and Intra-lock implants, which had the latest-generation thread design, always showed significantly higher values (e.g., IT: 18.6 and 18.6 Ncm, RT: 10.8 and 13.7 Ncm, RFA mean: 46 and 43 ISQ, in the 20 PCF density with the cortical sheet for TAC and Intra-lock, respectively). In particular, TAC implants also reached the highest RFA values in the lowest-density foam (19 ISQ). In conclusion, the present in vitro study demonstrated that TAC and Intra-lock apical designs and macro-geometries could play a key role in determining the PS and the polyurethane-implant contact in simulated post-extraction conditions in low-density artificial bone. Full article

(This article belongs to the Special Issue Feature Papers in Eng 2023)

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12 pages, 1606 KiB

Open AccessFeature PaperArticle

Transit Behaviour and Sociodemographic Interrelation: Enhancing Urban Public-Transport Solutions

by Aisha Hasan, Umair Hasan, Hamad AlJassmi and Andrew Whyte

Eng 2023, 4(2), 1144-1155; https://doi.org/10.3390/eng4020066 - 14 Apr 2023

Cited by 4 | Viewed by 1812

Abstract

Recent years have seen a considerable shift in the focus of public investment agencies from extensive roadway networks to a more planned approach that meets environmental, cost, and social dimensions more aptly. Past research has mainly explored the engineering aspect and cost parameters, [...] Read more.

Recent years have seen a considerable shift in the focus of public investment agencies from extensive roadway networks to a more planned approach that meets environmental, cost, and social dimensions more aptly. Past research has mainly explored the engineering aspect and cost parameters, while the human or social component is often neglected. This study aims to identify the trip-making behaviour of residents in an urban area towards bus transport network enhancement. Abu Dhabi, the location of study, is heavily dependent upon car travel, creating much congestion, which the local government seeks to address by enhanced public transport. This work examined eight public-transport routes in two zones, with data collected on both weekdays (n = 751) and weekends (n = 769). Multinomial logistic regression models showed that respondents highlighted overcrowded buses and traffic congestion as two of the main hurdles pertinent to urban routes in the bus network influencing their mode choice. Proposals pertinent to the local authority for further consideration need to factor in current low satisfaction with bus transit network coverage, low satisfaction with the quality of bus rides, inhibiting a mode shift from cars/taxis towards buses, cumulative income profiles of public-transport users, with findings that the low-income bracket is already at saturation, and that reducing congestion needs innovative (sociodynamic rather than technical road network) public-transport solutions. Full article

(This article belongs to the Special Issue Feature Papers in Eng 2023)

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11 pages, 260 KiB

Open AccessArticle

Frequency Analysis of Equivalent Property-Damage-Only (EPDO) Crashes at Intersections

by Mostafa Sharafeldin, Khaled Ksaibati and Ken Gerow

Eng 2023, 4(2), 1116-1126; https://doi.org/10.3390/eng4020064 - 10 Apr 2023

Viewed by 2061

Abstract

Traffic crashes are burdening societies with severe costs in terms of public health and economic loss. Intersection-related crashes are responsible for a large proportion of these losses due to their higher frequency and severity. Understanding the factors contributing to intersection crash frequency and [...] Read more.

Traffic crashes are burdening societies with severe costs in terms of public health and economic loss. Intersection-related crashes are responsible for a large proportion of these losses due to their higher frequency and severity. Understanding the factors contributing to intersection crash frequency and severity is essential to mitigate their grave consequences. This study covered the analysis of roadway risk factors, influencing the frequency of equivalent property-damage-only (EPDO) crashes at intersections. The study included developing a negative binomial modeling framework to examine nine years of intersection crash records in the state of Wyoming. The modeling results revealed the key role of pavement friction in intersection safety and EPDO frequency. The findings also demonstrated that intersection location, grade, road functional classification, road surface type, the presence of guardrails, right shoulder type, and horizontal curvature all influence the EPDO crash frequency at intersections. Full article

(This article belongs to the Special Issue Feature Papers in Eng 2023)

26 pages, 985 KiB

Open AccessFeature PaperArticle

The Present and Future of a Digital Montenegro: Analysis of C-ITS, Agriculture, and Healthcare

by Peter A. Kara, Ivana Ognjanovic, Ingo Maindorfer, John Mantas, Andras Wippelhauser, Ramo Šendelj, Luka Laković, Milovan Roganović, Christoph Reich, Aniko Simon and Laszlo Bokor

Eng 2023, 4(1), 341-366; https://doi.org/10.3390/eng4010021 - 29 Jan 2023

Cited by 6 | Viewed by 8907

Abstract

The digitization and general industrial development of Montenegro is a great challenge for engineering and science due to its special characteristics. As the accession of Montenegro to the European Union has been an ongoing agenda for over a decade now, and the accession [...] Read more.

The digitization and general industrial development of Montenegro is a great challenge for engineering and science due to its special characteristics. As the accession of Montenegro to the European Union has been an ongoing agenda for over a decade now, and the accession of the country is expected by 2025, adapting the interconnectivity and smart automation of Industry 4.0 plays an essential role in reducing the current gap between Montenegro and EU member states. In this paper, we investigate the present and potential future digitization efforts in the fields of Cooperative Intelligent Transport Systems (C-ITS), agriculture, and healthcare in Montenegro. Our work takes into consideration the characteristics of the country and analyzes the considerations and implications regarding the deployment of state-of-the-art technologies in the investigated fields. Full article

(This article belongs to the Special Issue Feature Papers in Eng 2023)

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Review

Jump to: Editorial, Research

47 pages, 16148 KiB

Open AccessReview

Amazon Natural Fibers for Application in Engineering Composites and Sustainable Actions: A Review

by Pedro Henrique Poubel Mendonça da Silveira, Bruno Figueira de Abreu Ferreira Cardoso, Belayne Zanini Marchi and Sergio Neves Monteiro

Eng 2024, 5(1), 133-179; https://doi.org/10.3390/eng5010009 - 12 Jan 2024

Cited by 5 | Viewed by 2983

Abstract

The Amazon rainforest, spanning multiple countries in South America, is the world’s largest equatorial expanse, housing a vast array of relatively unknown plant and animal species. Encompassing the planet’s greatest flora, the Amazon offers a tremendous variety of plants from which natural lignocellulosic [...] Read more.

The Amazon rainforest, spanning multiple countries in South America, is the world’s largest equatorial expanse, housing a vast array of relatively unknown plant and animal species. Encompassing the planet’s greatest flora, the Amazon offers a tremendous variety of plants from which natural lignocellulosic fibers (NLFs) can be extracted. In this century, NLFs, which have long been utilized by indigenous populations of the Amazon, have garnered interest as potential reinforcements for composites, whether polymer- or cement-based, in various technical applications such as packaging, construction, automotive products, and ballistic armor. A comparison with synthetic materials like glass, carbon, and aramid fibers, as well as other established NLFs, highlights the cost and specific property advantages of Amazon natural fibers (ANFs). Notably, the sustainable cultivation and extraction of ANFs, as alternatives to deforestation and livestock pasture, contribute to the preservation of the Amazon rainforest. This review article provides a comprehensive examination of recent studies directly related to ANF-reinforced polymer matrix composites. The specific advantages, proposed applications, and reported challenges are highlighted, shedding light on the potential of these unique natural fibers. Full article

(This article belongs to the Special Issue Feature Papers in Eng 2023)

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14 pages, 2529 KiB

Open AccessFeature PaperReview

Rheological Behavior of Cement Paste: A Phenomenological State of the Art

by Youssef El Bitouri

Eng 2023, 4(3), 1891-1904; https://doi.org/10.3390/eng4030107 - 4 Jul 2023

Cited by 3 | Viewed by 2966

Abstract

With the interest aroused by the development of modern concretes such as printable or self-compacting concretes, a better understanding of the rheological behavior, directly linked to fresh state properties, seems essential. This paper aims to provide a phenomenological description of the rheological behavior [...] Read more.

With the interest aroused by the development of modern concretes such as printable or self-compacting concretes, a better understanding of the rheological behavior, directly linked to fresh state properties, seems essential. This paper aims to provide a phenomenological description of the rheological behavior of cement paste. The first part is devoted to the most common testing procedures that can be performed to characterize the rheological properties of cement suspensions. The second one deals with the complexities of the rheological behavior of cement paste including the non-linearity of flow behavior, the viscoelasticity and yielding, and the structural build-up over time. Full article

(This article belongs to the Special Issue Feature Papers in Eng 2023)

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21 pages, 2154 KiB

Open AccessFeature PaperReview

A Review on Vibration Monitoring Techniques for Predictive Maintenance of Rotating Machinery

by Marcelo Romanssini, Paulo César C. de Aguirre, Lucas Compassi-Severo and Alessandro G. Girardi

Eng 2023, 4(3), 1797-1817; https://doi.org/10.3390/eng4030102 - 26 Jun 2023

Cited by 19 | Viewed by 11879

Abstract

Machine failure in modern industry leads to lost production and reduced competitiveness. Maintenance costs represent between 15% and 60% of the manufacturing cost of the final product, and in heavy industry, these costs can be as high as 50% of the total production [...] Read more.

Machine failure in modern industry leads to lost production and reduced competitiveness. Maintenance costs represent between 15% and 60% of the manufacturing cost of the final product, and in heavy industry, these costs can be as high as 50% of the total production cost. Predictive maintenance is an efficient technique to avoid unexpected maintenance stops during production in industry. Vibration measurement is the main non-invasive method for locating and predicting faults in rotating machine components. This paper reviews the techniques and tools used to collect and analyze vibration data, as well as the methods used to interpret and diagnose faults in rotating machinery. The main steps of this technique are discussed, including data acquisition, data transmission, signal processing, and fault detection. Predictive maintenance through vibration analysis is a key strategy for cost reduction and a mandatory application in modern industry. Full article

(This article belongs to the Special Issue Feature Papers in Eng 2023)

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19 pages, 1478 KiB

Open AccessReview

Skid Resistance of Asphalt Pavements

by Szabolcs Rosta and László Gáspár

Eng 2023, 4(2), 1597-1615; https://doi.org/10.3390/eng4020091 - 6 Jun 2023

Cited by 3 | Viewed by 3331

Abstract

Skid resistance of a road pavement surface is the force developed when a tyre is prevented from rotating and slides along the pavement surface. This property comes from the combination of the macro- and micro-texture of pavement. The skid resistance of an asphalt [...] Read more.

Skid resistance of a road pavement surface is the force developed when a tyre is prevented from rotating and slides along the pavement surface. This property comes from the combination of the macro- and micro-texture of pavement. The skid resistance of an asphalt pavement is an important parameter influencing driving safety on a road since there is a proven relationship between skid resistance and accident parameters. This paper deals with the measurement principle of pavement skid resistance (surface friction) including longitudinal and transverse friction. A high number of measuring devices of skid resistance are also introduced, highlighting their advantages and limitations. Moreover, the measurement policies in the European Union and in Hungary are outlined. Pavement surface texture is investigated, dealing with the levels of surface texture, the most common measuring techniques, the macro-texture features of asphalt types, as well as the Hungarian regulation in the field. As a related topic, the aggregate properties and their implication in the relevant Hungarian specification are introduced briefly as well. Some outcomes of the EU’s COST Action 354 on the development of unified European macro-roughness and skid resistance performance indicators and indices are also presented. Full article

(This article belongs to the Special Issue Feature Papers in Eng 2023)

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14 pages, 1788 KiB

Open AccessFeature PaperReview

Integrating Multi-Criteria Decision-Making Methods with Sustainable Engineering: A Comprehensive Review of Current Practices

by Anđelka Štilić and Adis Puška

Eng 2023, 4(2), 1536-1549; https://doi.org/10.3390/eng4020088 - 31 May 2023

Cited by 19 | Viewed by 6223

Abstract

Multi-criteria decision-making (MCDM) methods have gained increased attention in sustainable engineering, where complex decision-making problems require consideration of multiple criteria and stakeholder perspectives. This review paper provides a comprehensive overview of the different MCDM methods, their applications in sustainable engineering, and their strengths [...] Read more.

Multi-criteria decision-making (MCDM) methods have gained increased attention in sustainable engineering, where complex decision-making problems require consideration of multiple criteria and stakeholder perspectives. This review paper provides a comprehensive overview of the different MCDM methods, their applications in sustainable engineering, and their strengths and weaknesses. The paper discusses the concept of sustainable engineering, its principles, and the different areas where MCDM methods have been applied, including energy, manufacturing, transportation, and environmental engineering. Case studies of real-world applications are presented and analyzed, highlighting the main findings and implications for engineering practice. Finally, the challenges and limitations of MCDM methods in sustainable engineering are discussed, and future research directions are proposed. This review contributes to the understanding of the role of MCDM methods in sustainable engineering and provides guidance for researchers and practitioners. Full article

(This article belongs to the Special Issue Feature Papers in Eng 2023)

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20 pages, 1067 KiB

Open AccessReview

Applications of Machine Learning in Mechanised Tunnel Construction: A Systematic Review

by Feng Shan, Xuzhen He, Haoding Xu, Danial Jahed Armaghani and Daichao Sheng

Eng 2023, 4(2), 1516-1535; https://doi.org/10.3390/eng4020087 - 30 May 2023

Cited by 12 | Viewed by 3115

Abstract

Tunnel Boring Machines (TBMs) have become prevalent in tunnel construction due to their high efficiency and reliability. The proliferation of data obtained from site investigations and data acquisition systems provides an opportunity for the application of machine learning (ML) techniques. ML algorithms have [...] Read more.

Tunnel Boring Machines (TBMs) have become prevalent in tunnel construction due to their high efficiency and reliability. The proliferation of data obtained from site investigations and data acquisition systems provides an opportunity for the application of machine learning (ML) techniques. ML algorithms have been successfully applied in TBM tunnelling because they are particularly effective in capturing complex, non-linear relationships. This study focuses on commonly used ML techniques for TBM tunnelling, with a particular emphasis on data processing, algorithms, optimisation techniques, and evaluation metrics. The primary concerns in TBM applications are discussed, including predicting TBM performance, predicting surface settlement, and time series forecasting. This study reviews the current progress, identifies the challenges, and suggests future developments in the field of intelligent TBM tunnelling construction. This aims to contribute to the ongoing efforts in research and industry toward improving the safety, sustainability, and cost-effectiveness of underground excavation projects. Full article

(This article belongs to the Special Issue Feature Papers in Eng 2023)

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25 pages, 5093 KiB

Open AccessReview

A Critical Review and Bibliometric Analysis on Applications of Ground Penetrating Radar in Science Based on Web of Science Database

by Nehal Elshaboury, Eslam Mohammed Abdelkader, Abobakr Al-Sakkaf and Tarek Zayed

Eng 2023, 4(1), 984-1008; https://doi.org/10.3390/eng4010059 - 22 Mar 2023

Cited by 3 | Viewed by 3847

Abstract

Ground-penetrating radar (GPR) is an established technology with a wide range of applications for civil engineering, geological research, archaeological studies, and hydrological practices. In this regard, this study applies bibliometric and scientometric assessment to provide a systematic review of the literature on GPR-related [...] Read more.

Ground-penetrating radar (GPR) is an established technology with a wide range of applications for civil engineering, geological research, archaeological studies, and hydrological practices. In this regard, this study applies bibliometric and scientometric assessment to provide a systematic review of the literature on GPR-related research. This study reports the publication trends, sources of publications and subject categories, cooperation of countries, productivity of authors, citations of publications, and clusters of keywords in GPR-related research. The Science Citation Index Expanded (SCI-EXPANDED) and the Social Sciences Citation Index (SSCI), which can be accessed through the Web of Science Core Collection, are used as references. The findings report that the number of publications is 6880 between 2001 and 2021. The number of annual publications has increased significantly, from 139 in 2001 to 576 in 2021. The studies are published in 894 journals, and the annual number of active journals increased from 68 in 2001 to 215 in 2021. Throughout the study, the number of subject categories involved in GPR-related research fluctuated, ranging from 38 in 2001 to 68 in 2021. The research studies originated from 118 countries on 6 continents, where the United States and the People’s Republic of China led the research articles. The top five most common keywords are ground-penetrating radar, non-destructive testing, geophysics, electrical resistivity tomography, and radar. After investigating the clusters of keywords, it is determined that civil engineering, geological research, archaeological studies, and hydrological practices are the four main research fields incorporating GPR utilization. This study offers academics and practitioners an in-depth review of the latest research in GPR research as well as a multidisciplinary reference for future studies. Full article

(This article belongs to the Special Issue Feature Papers in Eng 2023)

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38 pages, 14901 KiB

Open AccessReview

Development and Applications of 3D Printing-Processed Auxetic Structures for High-Velocity Impact Protection: A Review

by Raí Felipe Pereira Junio, Pedro Henrique Poubel Mendonça da Silveira, Lucas de Mendonça Neuba, Sergio Neves Monteiro and Lucio Fabio Cassiano Nascimento

Eng 2023, 4(1), 903-940; https://doi.org/10.3390/eng4010054 - 8 Mar 2023

Cited by 11 | Viewed by 8335

Abstract

Auxetic structures (AXSs) are a novel class of materials with unique mechanical deformation behavior associated with negative Poisson ratio. The combination of AXS configurations with various types of materials has unveiled a wide field of applications, including military high-velocity protection against explosions and [...] Read more.

Auxetic structures (AXSs) are a novel class of materials with unique mechanical deformation behavior associated with negative Poisson ratio. The combination of AXS configurations with various types of materials has unveiled a wide field of applications, including military high-velocity protection against explosions and ballistic projectiles. However, the characteristic geometric re-entrant model of AXSs imposes limitations and difficulties when using conventional manufacturing methods to assemble the structure lattice. Additive manufacturing (AM) has recently been explored as a more efficient and cost-effective method to fabricate AXSs, regardless of the type of material. This review paper focuses on the development and applications of AM processed AXSs. The review highlights the significance and great potential for this class of materials that can be produced relatively fast and at a low cost. The advantages of AXS/AM are expected to extend to important industrial sectors, particularly for military ballistic armor, where the feasibility for products with improved properties is critical. The use of AM offers a viable solution to overcome the difficulties associated with the conventional manufacturing methods, and thus offers greater design flexibility, cost efficiency, and reduced material waste. This review paper aims to contribute to the understanding of the current state-of-the-art and future research prospects for the production and applications of AXS/AM. Full article

(This article belongs to the Special Issue Feature Papers in Eng 2023)

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