Maritime autonomous surface ship (MASS) technologies promise substantial advantages and benefits. These technologies are not expected to immediately replace existing commercial vessels and crews, but they already face challenges related to regulation, legislation, reliability, and scepticism. Although ship crews are considered the primary operators and adopters of unmanned vessels, they must continue to refine their skills in response to future challenges associated with technological advancement. Given the aforesaid circumstances, this study proposed various recommendations for crew training following the transition to Level 2 MASS technologies. The decision analytic network process was used to analyse the causality and weight of both main constructs and their sub-criteria. The results indicate that crew competencies is the most crucial construct. Future ship crews will require training focused on their ability to monitor MASS decision-making and increasing their proficiency in integrating software and hardware. MASS vessels should be designed with a modular approach, and more extensive training in artificial intelligence should be provided to ship crews.
Fast marine vessels often operate in the semi-displacement mode when hydrodynamic lift plays an increasingly important role and hull trim and sinkage become speed-dependent. The shallow-water effects may also alter hydrodynamic characteristics of such hulls. In this study, computational fluid dynamics simulations have been carried out for a high-performance semi-displacement hull. Numerical results were validated against deep-water test data over a broad speed range. Shallow-water simulations were conducted at three speeds ranging from the fast displacement to semi-planing regimes at the critical depth-based Froude number and three shallow water depths. The hull hydrodynamic characteristics and associated wave patterns are presented. The appearance of a solitary wave and drag hump at a lower speed and reduction of drag in very shallow water are observed. These results can be useful for designers of semi-displacement vessels.
The CDIOTM Initiative is an innovative educational framework providing students with an education stressing engineering fundamentals set in the context of Conceive-Design-Implement-Operate (CDIO) real-world systems and products. The focus of the CDIO Initiative is to produce industry-ready graduates through practice and it has become increasingly popular, especially in engineering education. The CDIO Initiative has used various platforms such as wind turbines and eco-cars for developing the corresponding curriculum of engineering education. This paper aims to introduce and integrate robotic sailboats into the CDIO Initiative through the corresponding curriculum development for robotics education. Initial results of such an approach have demonstrated the suitability as well as the benefits of using robotic sailboats for the CDIO Initiative of robotics education.
The size of the aft control surfaces required on a submarine will depend on its length/diameter ratio, and the desired stability in the vertical plane. This is an important element in the design of a submarine. This paper presents a simplified way of determining the size of the aft control surfaces in order to achieve the desired level of stability in the vertical plane at the very early stage in the design of the submarine. The results are compared with the sizes of the aft control surfaces on a range of existing submarines, and it is shown that there is good agreement between the simplified prediction approach, and the actual sizes used.
The challenges commercial shipping faces in terms of the IMO decarbonisation agenda in combination with volatile freight and capital markets call for the drastic rethinking of the way ships are designed and operated in the next decades. This paper presents a novel approach that allows the creation of a robust, market-informed, simulation-supported framework, able to systematically explore at an early stage the multi-variable, multi-objective design space for large oceangoing commercial vessels (bulkers, tankers, containerships etc.). It results in a rigorous exploitation of the available solutions improving the decision-making process. The Robust Holistic Optimisation Ship Design Approach (RHODA) combines voyage simulation with multiple layers of uncertainty: voyage, environmental, market and method. A case study on its impact on the design optimisation path for a conventional bulk carrier and its sensitivity and comparison to “deterministic” approaches is presented.
In this paper hydrodynamic coefficients of AUV including maneuvering damping and added mass coefficients are investigated up to the third order using the FVM. The PMM module is implemented in two situations to calculate the moment and force for yaw and sway motions. To estimate the hydrodynamic coefficients, the sixth-order polynomial equations are interpolated for forces and moments in terms of velocity and acceleration (linear and rotational). Using the obtained equations and the determination of each coefficient, the maneuvering damping and added mass coefficients are extracted up to the third order. The results show that the added mass coefficient of the yaw moment is 1.94, which shows an error of less than 0.5% compared to the experimental results. On the other hand, the ratio of the length to the diameter is investigated. The approach presented in this study will increase the accuracy and reduce the calculation time.
Aluminum oxide (Al2O3) is a ubiquitous material with a wide range of applications due to its exceptional properties. This paper explores the relationship between the structural characteristics of Al2O3 and its surface wettability, as measured by contact angle. Using X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy, the crystalline structure and chemical properties of the epoxy-Al2O3 samples were characterized. Contact angle measurements were performed to evaluate the wettability of epoxy-Al2O3 surfaces. The results reveal a strong correlation between the structural characteristics and the hydrophobic nature of the coating surfaces. These findings have significant implications for the use of epoxy-Al2O3 coatings in applications requiring specific wettability properties.
Green machining represents a paradigm shift in sustainable manufacturing, combining technological innovation with environmental stewardship. Traditional machining processes, while highly efficient, contribute to environmental deprivation due to excessive energy consumption, waste generation, and reliance on toxic cutting fluids. Green machining techniques have emerged as viable alternatives, promising reduced environmental footprints without compromising productivity or quality. The most recent developments in green machining have focused on integrating renewable energy sources, advanced tool materials, and Industry 4.0 technologies to enhance efficiency and precision. However, there are challenges to be overcome, such as the high initial investment costs and specialized infrastructure requirements. This paper looks into the recent developments, challenges, and future directions of green machining, with a focus on its potential for aligning industrial growth with global sustainability goals. The results indicate that green machining techniques are not only beneficial to the environment but also provide economic benefits, signalling a more sustainable manufacturing future.
Melt- quenching technique is employed for mixing Glassy samples whose chemical composition xLi₂O–(0.45–x)Bi₂O₃–0.15ZnO–0.40P₂O₅ (x = 0.05, 0.15, 0.25, 0.35). The glassy system’s electrical, dielectric, and physical characteristics are influenced by the varying in lithium oxide (x) concentration. Increasing Li₂O content conduct to decreased average density and molar volume, indicating structural compaction. This is supported by higher oxygen packing density and lower molar volume per oxygen atom. In higher Li₂O content leads to less inter-nuclear fractionation, of lithium ions (RLi), allowing for better ionic conduction. Dielectric studies, based on Bergman’s model, reveal that the dielectric constant and dielectric loss increase with temperature while decreasing with higher frequencies, indicative of thermally activated dipolar relaxation. The charge transport and relaxation mechanisms were further explored using modulus scaling, showing a temperature-independent response. Analysis via the Kohlrausch–Williams–Watts model indicates non-Debye-type relaxation behaviour for charge carriers, underscoring the complex dynamics within the glass matrix. The impedance spectrum demonstrates enhanced conductivity of ions with elevated LiO concentration, which is fueled by effective mobility of charged carriers and decreased large amounts of resistance. The synchronize addition of lithium ions improves both ionic conduction and dielectric behavior. This study highlights the potential of these glassy systems as innovative materials for energy storage applications, with a particular focus on advancing electrode material development.
Maritime transportation has gradually moved towards using Maritime Autonomous Surface Ship (MASS) to reduce the cost of human resources, increase people's safety and improve operational efficiency. This article explores which berth of the Kaohsiung port is suitable for mooring a MASS. After reviewing the literature and gathering experts' opinions, a hierarchy structure with three assessment aspects, nine criteria and three potential alternatives suitable for the berth selection of a MASS were obtained. We then integrate the subjective Analytic Hierarchy Process (AHP) method and the objective Automatic Identification System (AIS) technique to select an appropriate berth for the mooring of a MASS. The empirical result indicates that "the 7th Container Centre" of the Kaohsiung port is more suitable for mooring a MASS. Moreover, the conclusions and recommendations are given to maritime government authorities and port operators for reference when upgrading from traditional ports to intelligent ports in the future.
This paper explores the use of the incompressible and viscous Finite Point Method (FPM) embedded within a generic structural finite element software suite to validate free surface flows and fluid-structure interactions around a naval hull. The study proposed an inflow-outflow and towing tank setup to investigate the wake wave profiles, and wave-making resistance around the model DTMB5415 naval hull. FPM was successful in predicting the wake wave profiles relatively well without major deviations. The viscous effects were found to increase the accuracy of the wave profiles without much dissipation in the wave propagation. Both methods of simulation also accurately captured the wave-making resistance between the Froude number of 0.15 and 0.4 but tended to overpredict at other speeds. Although still water results for a rigid hull have been presented here, the results are an encouraging first-look at the use of a structural solver with embedded fluid coupling for analysing ship response. The long-term goal is to use the same modelling approach with waves and fully structural models within the single software suite.
This paper builds upon the 2021 IJME publication by the same authors, which introduced the application of network theory to the design and evaluation of a simplified submarine power and propulsion system for early-stage ship design. The current work presents significant advancements from that initial investigation, detailing the UCL Network Block Approach (NBA). The NBA integrates the strengths of a proven 3D Computer Aided Ship Design (CASD) system's architecture-driven approach using a network theory approach, specifically for the design of distributed ship service systems in complex vessels, demonstrated through a submarine case study. The proposed approach has now been validated through three design sensitivity studies, which examined variations at three levels: overall ship performance, main-level design styles, and micro-level design styles. The findings indicate that the NBA facilitates the holistic investigation of distributed ship service systems during early-stage ship design. Additionally, it enables naval architects and marine engineers to quickly size and balance energy requirements for different distributed systems and visualise the intricate structure of submarine systems within a 3D CASD environment and a 3D multiplex network layout. Furthermore, the NBA provides a basis for assessing the potential impacts of emerging technologies, such as the development of net-zero carbon based energy solutions for future naval vessels.
This study presents a novel approach for ship fire assessment using a custom hybrid model and tailored image processing. The model utilizes auto-adaptive edge and colour detection algorithms to identify various fire features, including flames, smoke, and fire extent. It contributes significantly to firefighting research, particularly in ship fire detection, offering potential for early intervention in dynamic marine environments. Validation with the Carnival Freedom cruise ship fire confirms the model's practicality. In summary, this study showcases the hybrid model's effectiveness in fire analysis and firefighting performance evaluation, paving the way for further research in diverse scenarios. The insights gained are relevant for fire monitoring and evaluation in various contexts, encouraging future investigations into the model's adaptability and efficient fire extinguishment strategies, enhancing fire safety and management.
The present work is an attempt to analyse the effect of post processing time interval between friction stir processing and TIG welded aluminium joint to overcome the defects and increase the strength of the weld. Friction stir processing was carried out on each TIG welded AA5083 aluminium joints with filler wire ER 5356. Experimental studies for time interval 0 minutes, 45 minutes and 90 minutes varying current rate, gas flow rate and feeding rod diameter using Taguchi design of experiments. The samples were subjected to determine the ultimate tensile strength and hardness. The experimental data so obtained was used to obtain the regression equation using Taguchi design of experiments. The equation so obtained was used for parametric investigations for time intervals with a span of 15 minutes in order to determine the variations in the mechanical properties such as ultimate tensile strength and hardness. It was found that Friction stir processed TIG welded joints produced better results with regards to ultimate strength and hardness if the time interval between TIG and Friction stir processing was reduced.
The image-based life model is a method used to analyze the intelligent maintenance and safe operation of industrial roller bearings. However, due to variable operating conditions, the prognosis of bearing vibrations is often complicated by the variable operating conditions of real industry. These characteristics reflect the deterioration trends of the bearings, making the development of life prediction models exceptionally challenging. This manuscript presents a solution to address these difficulties by proposing the concept of an image driven life prediction model. It leverages lifespan data from roller bearings, encompassing regular operational phases to malfunction. An image state matrix designed to differentiate between various operational states of roller bearings. Historical bearing examination data from the University of Cincinnati Laboratory Center are employed to construct a life probability density function. The variables integrated into the state matrix model are dynamically adapted to enable real-time monitoring of bearing conditions in industrial applications. This work not only provides theoretical insights but also highlights the inadequacies of threshold limits in the context of the big data era. Long-range prediction can be enhanced by fusion of image-based state matrix model with traditional models for fault detection and diagnosis. Visual information through image help to train the model with real operating conditions of industrial bearing.
Using mineral oil in the cold rolling of aluminum alloy harms the environment. Researchers are developing biodegradable lubricants to take the place of mineral oils. A tribological analysis for the interface between EN31 steel and aluminum 6063 alloy under full flooded lubrication has been done on the pin-on-disc tribometer. In this study, neem and coconut oil have been used as biodegradable oils in fully lubricating conditions between the interfaces of surfaces. Taguchi's optimization method has been applied to optimize process parameters, such as load, lubricants, and sliding speed. Four type of lubricants LT (dry, coconut oil, neem oil, and rolling lubricant,) were tested, along with sliding speeds s (1.25, 1.5, 1.75, and 2.0 m/s) and loads W (4, 6, 8, and 10 kg). L16 orthogonal array by Taguchi's optimization technique has been used for the design of experiment. An analysis has been conducted on the tribological properties between the interface of Al 6063 and EN 31 steel. The findings demonstrated that biodegradable oils, such as coconut and neem oil, had good tribological properties. According to S/N analysis, the optimal parameters for the coefficient of friction (COF) were observed as, lubricant at first level, sliding speed at third level, and load at first level (LT1-s3-W1) considering the smaller-the-better condition. For specific wear rate (SWR) optimal parameters were lubricant at first level, sliding speed at third level, and load at fourth level (LT1-s3-W4) considering the smaller-the-better condition. S/N analysis revealed that lubrication type had the most effective in minimizing COF and SWR. Regression models were developed for COF and SWR using ANNOVA. This model had a good agreement with results of experiments.
The present work explores the effect of various process parameters on friction stir processed Tig welded AA5083 aluminium joints. TIG welding was carried out with process parameters such as Gas flow rate, current rate and Filler wire diameter, whereas friction stir processing parameters were RPM, tilt angle and traversing speed. TIG welding parameters Gas flow rate, current rate and Filler wire diameter were varied between 10 to 14 Litre/minute, 130 to 160 A and 1.6 to 3.2 mm respectively. TIG welded aluminium alloys were subjected to various process parameters including various filler wires ER 4043, ER4047 and ER5356 in order to determine the optimised joint having least problems such as hot cracking, Porosity but couldn't remove completely. Friction stir processing on TIG welded joint was introduced on the optimised TIG welded sample in order to reduce such unwanted defects and improve the mechanical properties such as microstructure, ultimate tensile strength and hardness. Friction stir processing has remarkably improved the mechanical properties.
Over the last few years, the alarming rate of increase in greenhouse emissions across the world due to continuous growth in cooling and heating requirements has caused a rise in the global temperature. The use of energy-efficient systems, devices, and renewable energy systems are need of the hour as these can curtail greenhouse gas (GHG) emissions and will aid in sustainable development. In the cooling sector, most commercial and domestic refrigeration and air-conditioning systems run on the conventional vapour compression refrigeration (VCR) cycle. The irreversibility occurring in the capillary tube leads to significant energy loss. Also, hydrofluorocarbons (HFC) refrigerants, are being used in these systems, consuming more energy for the operation of the system and contributing larger GHG leading to enhanced climate change. The literature has demonstrated that deploying an ejector in lieu of the typical throttling valve can minimize the energy loss. In addition to this, the use of environment-friendly refrigerants in these systems will also keep a check on levels of emissions that lead to environmental change. In the prevailing study, a parametric performance analysis is executed of the ejector-assisted vapour compression refrigeration system (EVCR) employing ammonia(R717), propane(R290), and isobutane(R600a) as refrigerants with a uniform pressure ejector model. I-st law and IInd law analyses of the EVCR system are accomplished for a range of condenser temperature (T-cndr = 30 degrees C to 60 degrees C), evaporator temperature (T-evpr = 5 degrees C, -5 degrees C and -15 degrees C), and pressure drop (delta P = 0.01 to 0.50 bar) in the suction chamber. Variations in performance parameters such as coefficient of performance (COPEVCR) & % improvement in COPEVCR (%COPEVCR, (imp)), volumetric cooling capacity (VCCEVCR) & % improvement in VCC (%VCCEVCR, imp), optimum area ratios (AR(opt)), pressure lift factor (PLF), total exergy destruction (E-D,E- Total), and IInd law efficiency (eta(exergetic)) of the EVCR system for the above range of the operating parameters are reported in this study. It is observed from the results that at T-cndr = 40 degrees C and T-evpr = 5 degrees C, R600a yields the maximum COP EVCR of 6.14 whereas the R290 gives the highest % COPEVCR, imp of 12.78% and %VCCEVCR, imp = 9.96% compared to the other two refrigerants. Also, it is observed from the IInd law analysis that R717 gives the maximum E-D,E- Total of 59.64 kW, and eta(exergetic) of 37.61% whereas R290 and R600a give values of eta(exergetic) as 36.90% and 37.56%.
An experimental tested examination of turbulent (zigzag) flow heat transfer improvement and features of friction in the flow of a circular pipe. The circular pipe tapes tidied come in two varieties: (i) standard tapes with twisted and (ii) alternate (substitute) twisted flow in both directions, counter clockwise and clockwise (CC & C) tapes. Eight varied types of CC-C are experimented in this work. There are tapes with 3 types of twist ratios available; y/w = 2.5, 3.5, and 4.5 & every having 3 twist angles given theta = 30(theta), 60(theta)& 90(theta). Water was used as the functioning fluid in the experiments and with Reynolds numbers (Re) ranging between 2000 and 32000. Under the same operating conditions, twisted-tapes CC--C have a greater rate of transfer of heat, factor of friction & transfer of heat enhancement index than normal tapes. The findings also show that as the twist ratio values decrease, the heat transmission rate of the CC-C tapes enhances but the twist angle increases with increased heat transfer. The maximal heat transfers more than those with the normal(plane) tube near improvement indexes CC & C twisted tapes with theta = 90(theta) are 1.40, 1.34, and 1.30, respectively. When using CC--C twisted tapes, there is additional discussion of the connection between the friction factor (fr) and the Nusselt umber (Nu). The experimental result is within +14 and -14 percentage (%) of the expected Nu number and friction factor (fr), respectively.
The Internet of Vehicles has transformed marine applications through better connected technology and automated systems, but these systems suffer from substantial vulnerability to online attacks that undermine security and reduce performance. Traditional ways of detecting attacks from centralized systems create performance delays with high computations and privacy threats which are severe issues in marine areas with poor infrastructure. Our research creates an enhanced machine learning (ML) approach through Federated Learning (FL) for secure attack discovery in IoV marine systems. The framework enables decentralized model training across multiple nodes without sharing raw data, preserving privacy, and minimizing bandwidth usage. Advanced feature engineering and optimization techniques are employed to improve the detection accuracy and computational efficiency of the FL-based model. Comprehensive experiments are conducted on CICIDS2017datasets to evaluate the framework's performance in detecting diverse cyber threats, including spoofing, DoS attacks, and so on. Results demonstrate significant improvements in A(accuracy), P-preecision, R-recall, and F1(score) of 98.8% compared to conventional centralized methods. This study highlights the potential of FL-driven approaches to enhance cybersecurity in IoV, offering a scalable and privacy-preserving solution for secure marine operations.
