Line Configuration Research Articles

Dynamic response analysis of alternative mooring system designs for a 15 MW floating wind turbine with an emphasize on different limit states

With the advancement of wind turbines into deeper and more distant waters, and the increase in turbine power, the design of mooring systems for large floating wind turbines presents significant challenges. This paper, based on a water depth of 100 meters, focuses on a 15 MW eccentric semi-submersible wind turbine platform. A time-domain fully coupled numerical model is established, and the mooring system design is carried out. A parametric investigation is conducted on the influence of different mooring parameters on the floater's motion, line configuration, mooring tension, and pretension. The study considers operational conditions, extreme conditions, and accidental conditions such as mooring line failure. It emphasizes the effects of factors such as mooring line length, horizontal mooring angle, fairlead height, and components in hybrid mooring systems, including concentrated mass, buoy volume, and the configuration scheme of weight and buoy blocks. Among various mooring schemes, an optimized design is selected for further dynamic response analysis to verify the feasibility of the scheme. Through comprehensive analysis of various mooring parameters, this paper summarizes the influence patterns of different mooring system design parameters on the dynamic response of floating wind turbines, providing a theoretical foundation and design guidance for subsequent engineering applications.

The effects of longitudinal joint assembly imperfections on the internal forces in segmental linings

AbstractDuring the assembly of concrete segments into a tunnel lining, small geometric imperfections are unavoidable. In the longitudinal joints, they lead to contact deficiencies, which affect the eccentricities of the forces transferred through them. This influences the development of internal forces along the lining's circumference. However, it is often not realistically considered in structural calculations. In this paper, the effects of longitudinal joints assembly imperfections on the lining's internal forces were investigated by employing finite element models for various lining configurations. The results show that assembly imperfections have an unfavorable effect on the internal forces in most cases. Depending on the loading situation, this can lead to more required reinforcement and higher utilization ratios in the segments field and joints compared to perfectly assembled linings. Stiffer and less deformable configurations are at higher risk of experiencing more severe effects. In systems at risk, an individual assessment is recommendable. Therefore, a simplified method is introduced that requires a significantly reduced modeling effort and calculation time and lower software capabilities.

Evaluation of production line expansion efficiency using computer simulation

Abstract The article discusses the application of computer simulation in the optimization of production processes, particularly in the context of analyzing scenarios related to the addition of new production lines. The conducted research and simulations have shown that computer simulation is a key tool for precise modeling and analysis of various options, allowing for better understanding and optimization of production activities. The article presents the theoretical foundations of simulation along with practical examples of its application, focusing on assessing the impact of different production line configurations on the overall system’s efficiency. The analysis of benefits includes shortening the production cycle time, increasing flexibility, and improving operational efficiency. The challenges associated with implementing computer simulation, such as the need for specialized knowledge and the necessity for continuous updates of simulation models, are also discussed. Based on the research and analyses conducted, the article demonstrates that computer simulation is an effective tool supporting strategic and operational decision-making in production management, particularly in the context of expanding production infrastructure.

Wasserstein distributionally robust learning for predicting the cycle time of printed circuit board production

This paper proposes a Wasserstein distributionally robust learning (WDRL) model to predict the production cycle time of highly mixed printed circuit board (PCB) orders on multiple production lines. The PCB production cycle time is essential for optimizing production plans. However, the design of the PCB, production line configuration, order combinations, and personnel factors make the prediction of the PCB production cycle time difficult. In addition, practical production situations with significant disturbances in feature data make traditional prediction models inaccurate, especially when there is new data. Therefore, we establishe a WDRL model, derive a tight upper bound for the expected loss function, and reformulate a tractable equivalent model based on the bound. To demonstrate the effectiveness of this method, we collected data related to surface mounted technology (SMT) production lines from a leading global display manufacturer for our computational experiments. In addition, we also designed experiments with perturbations in the training and testing datasets to verify the WDRL model’s ability to handle perturbations. This proposed method has also been compared with other machine learning methods, such as the support vector regression combined with symbiotic organism search, decision tree, and kernel extreme learning machine, among others. Experimental results indicate that the WDRL model can make robust predictions of PCB cycle time, which helps to effectively plan production capacity in uncertain situations and avoid overproduction or underproduction. Finally, we implement the WDRL model for the actual SMT production to predict the production cycle time and set it as the target for production. We observed a 98–103 % achievement rate in the last 20 months since the implementation in September 2022.

Mitigation of electric field near overhead transmission lines using electromechanical compensation based on genetic algorithm

The electrical field is a function of both the voltage and the configuration of the overhead transmission line (OTL); thus, mitigation of the electrical field could be achieved by either electrical compensation or mechanical rearrangement of the line configuration. In the mechanical rearrangement method, the conductor positions are optimized under certain constraints so that the electrical field has the minimum possible value. In the proposed research, OTL mechanical rearrangement is improved using electrical compensation based on a genetic algorithm (GA). The electrical compensation is implemented by inserting a combination of passive series and shunt elements in each phase, creating an electric voltage imbalance. GA is an evolutionary optimization algorithm used to minimize the electric field near residences as a fitness function. The positions of conductors and passive-reactive elements are represented as genes. In addition, this paper includes a case study on a 500-kV high-voltage overhead transmission line. The results show that when passive-reactive compensation is combined with mechanical compensation, the lowest electric field can be obtained. Electrical compensation improves the mechanical rearrangement method by approximately 18.6% (the total reduction with mechanical compensation of only about 34% is increased to more than 52% with electromechanical compensation).

Combination of Boundary Elements and the Ellipsoid Method for Optimizing the Electromagnetic Fields of Overhead Power Lines

ABSTRACTThis study proposes a numerical approach aimed at mitigating electromagnetic field intensities at ground level generated by overhead power lines. The methodology integrates the boundary element method for field evaluation with the ellipsoid method for field optimization, while adhering to critical design and safety constraints. The optimized power line configurations, derived from this integrated approach, achieved significant reductions in both electric and magnetic field magnitudes at ground level without compromising any specified constraints. Moreover, the research findings demonstrate the robustness, efficiency, and practical applicability of the proposed methodology in the design of optimized power lines, offering potential for increased power transfer capability, and decreased environmental and health impacts.

Profit-oriented balancing of two-sided disassembly lines with resource-dependent task times

PurposeAs a result of environmentally conscious production requirements in the world, the concept of disassembly has been a focus of interest by researchers and practitioners over the last two decades. Disassembly is an important process in circular economy to recover and reuse of parts and materials. End-of-life and large-sized products such as minibuses and trucks may be disassembled on two-sided lines. The ability of using both right and left sides of two-sided lines may increase line efficiency and reduce space requirements across the line. This paper aims to address a two-sided disassembly line balancing problem (TSDLBP), which deals with assigning disassembly tasks, various equipments and assistants to the workstations to maximize total net recovery profit of the line.Design/methodology/approachA detailed explanation of the TSDLBP is first presented in the paper. A new 0–1 integer linear programming model is then proposed for the TSDLBP, aiming at maximizing total net recovery profit from disassembly of products. A set of test problems is generated, and an experimental analysis is conducted to make a comparison between traditional one-sided disassembly lines (TOSDL) and two-sided disassembly lines by means of performance improvement rate.FindingsOptimal results are obtained in 132 (81.48%) out of 162 the TOSDL balancing problems, while 92 (56.79%) out of 162 the TSDLBP using the proposed model. Total net recovery profits are compared on 88 problems for which optimal solutions are obtained in both the TOSDL and the TSDLBP. Results showed that implementing two-sided disassembly lines provides 29.18% increment in total net recovery profit compared to the TOSDL. Furthermore, the effects of different parameter levels on the net recovery profit are analyzed using two-way analysis of variance. According to the results, implementing two-sided disassembly line configuration increases total net recovery profit of the line significantly compared to traditional disassembly line configuration.Originality/valueThe use of disassembly lines has become essential because of increasing consumption that results in a huge number of end-of-life products in the world. Two-sided disassembly lines may be preferred for dismantling large-sized products due to their high disassembly capacity and fewer space requirements. This paper proposes a new mathematical model for disassembly line balancing problem. The proposed model differs from the existing models by means of efficiently assigning limited disassembly resources as well as assigning disassembly tasks to the workstations to maximize total net recovery profit of the production system. The model allows decision-makers to consider several resource limitations when balancing their disassembly lines. The paper also provides a comprehensive experimental study to compare traditional and two-sided disassembly lines by means of profitability of disassembly processes.

The role of process monitoring devices and digital line balancing in achieving operational excellence in garment manufacturing

This study investigates the transformative potential of integrating digital technologies with lean manufacturing principles to address the evolving challenges in the garment industry. The industry demands high-quality products, rapid delivery, cost efficiency, and production flexibility to maintain competitiveness and sustainability. While traditional lean methods have focused on waste reduction and process optimization, the advent of digitalization offers unprecedented opportunities for enhancing operational excellence. This research specifically examines the role of Internet of Things-based Process Monitoring Devices (PMDs) and digital line balancing in achieving these goals. PMDs, integrated within a digital lean framework, facilitate continuous monitoring of machine performance and operator efficiency, providing real-time insights into operational processes. This real-time visibility enables data-driven decision-making and centralized analysis, fostering agility and responsiveness. Furthermore, this study presents a dynamic digital line balancing algorithm that optimizes sewing line configurations and workload distribution. This dynamic approach allows for real-time adaptations in production flows to mitigate bottlenecks and boost productivity. By exploring the synergistic relationship between PMDs, digital line balancing, and lean principles, this paper contributes to a comprehensive understanding of how digital solutions can revolutionize operational efficiency in the garment manufacturing sector.

Hinotori™ robotic esophagectomy: a feasibility cadaver study.

This preclinical feasibility study investigates the potential of utilizing the hinotori™ robot system for esophagectomy. In three human cadaver models, the esophagus was successfully mobilized and resected using the hinotori™ system, with a mean thoracic procedure time of 57minutes. The system allowed for precise dissection and radical lymphadenectomy without arm collision, attributed to its versatile design and docking-free trocars. Standard robot-specific patient positioning, including a 35° left lateral inclination, and trocar placement in a posterior axillary line configuration were employed. Notably, trocars suitable for both laparoscopy and the hinotori™ robot were utilized, providing flexibility in trocar selection. Unique features, such as the ergonomic console and pointer-based pivot point identification system, contributed to procedural success. While these findings highlight the promising potential of the hinotori™ system in advancing esophageal surgery, further clinical studies are warranted to validate its reproducibility and clinical utility. Additionally, enhancements to the pivot point identification system and evaluation of the arm base's features may further optimize surgical outcomes.

Enhancing Marine Topography Mapping: A Geometrically Optimized Algorithm for Multibeam Echosounder Survey Efficiency and Accuracy

This research introduces a new multibeam survey line model that optimizes geometric relationships to improve the efficiency and accuracy of surveys over complex seabed topographies. Since existing multibeam echosounder systems have limitations in handling complex terrains, this study presents an advanced model to enhance data quality and operational efficiency. By strategically designing survey lines and optimizing coverage strategies, this paper achieves the optimal configuration of survey lines for secondary measurements in marine areas, ensuring high precision and reliability of measurement data. Experimental results show that the new model significantly outperforms existing technologies in terms of effective coverage area and measurement accuracy, with an average coverage rate of over 95%, higher than existing models, and a weighted average overlap rate of 3.18%, greatly improving the economic efficiency of measurements by reducing redundant coverage and minimizing operational costs. These findings confirm the advantages of the new model in practical applications and offer valuable technical support for advancing seabed mapping technology.

Mass customization using hybrid manufacturing and smart assembly: An optimal configuration and platform design approach

Hybrid Manufacturing (HM) and smart assembly stand as pivotal pillars in advanced smart manufacturing systems, offering manufacturers highly efficient and adaptable solutions for manufacturing. This paper delves into the configuration of a production line that integrates HM and assembly stages, each comprising multiple cells, with each cell housing one or more parallel stations. The objective is to manufacture a family of final assemblies, leveraging the platform concept to defer mass customization to later stages and thereby minimize processing costs. A mathematical programming model is proposed to identify the optimal configuration for such production lines, considering constraints such as an allowable capital cost and machine availabilities. In addition, the precedence, inclusion, and seclusion restrictions imposed on the part family are considered. The proposed mathematical programming model aims to delineate which HM features are processed in the part platform cell versus those processed in the mass customization (part variants) cells. Simultaneously, the model determines the components (variants from the HM stage) of final assemblies processed in the assembly platform cell, as well as components assembled or disassembled in the final assembly cells. Furthermore, the model seeks to determine the required number of stations in each cell to meet periodic demand. The overall objective of the model is to minimize the capital and the processing cost. A detailed case study illustrates the effectiveness of the proposed configuration approach and mathematical model. The proposed model is solvable in a few seconds by using commercial solvers.

Enhancing Operational Risk Management in Distribution Networks: A Comprehensive Framework

The ongoing expansion of power grid infrastructure has led to more complex line configurations and increased operational intricacies. Presently, there’s a noticeable gap in targeted, categorized analysis of operational factors influencing the risks and compliance issues in distribution network operations. The challenge in prioritizing and assessing these risks is compounded by the lack of measurable indicators, posing safety risks at operational sites. This study presents a comprehensive analysis of risk factor dimensions in distribution network operations and introduces measurable indicators for these risks. We propose a three-level risk assessment framework for distribution network operations, categorizing risks associated with personnel, the operational environment, equipment and management shortcomings. The Analytic Hierarchy Process (AHP) is utilized to determine the weights of 34 specific risk indicators within this framework. Furthermore, we explore the implementation of this risk assessment model, considering the real-world conditions of distribution network management centers, operational sites and inspection equipment. The practicality of the proposed framework and methods is validated through a case study of a power supply bureau’s distribution network operations. This research aims to enhance the safety risk management strategies in power grid companies, offering insights for improving on-site operational risk control in these enterprises.

Identifying restoration priorities for habitat defragmentation: a case study in Alberta’s oil sands

ContextAnthropogenic habitat loss and fragmentation are major threats to ecosystems and a focus in conservation. However, conservation is often limited to considerations of site-level processes neglecting the effect of the surrounding landscape that might limit the effectiveness of restoration efforts.ObjectivesUsing seismic lines in Alberta’s oil sands as a case study, we demonstrate an approach that integrates spatial configuration of anthropogenic footprints to prioritize habitat defragmentation.MethodsWe quantified the effects of seismic line density and configuration on functional footprints for caribou, butterfly diversity, and vascular plant diversity, to predict whether edge effects are more pronounced under different line densities and configurations. We then estimated the portion of the original functional footprint that would persist in the landscape due to the co-occurrence with other anthropogenic activities.ResultsWe found that functional footprint for caribou grows rapidly as habitat loss increases. In contrast, butterflies and plants exhibited a more gradual and linear growth in functional footprints at more local scales. This effect varies based on configuration of lines, either suppressing or facilitating the effect of habitat loss on functional habitats. Finally, restoration of all seismic lines without considering other footprints would reduce the original functional footprint by only 57% for caribou.ConclusionsRestoration efforts for habitat defragmentation rarely consider the spatial configuration of linear features, particularly as it relates to the co-occurrence of other footprints that are not being restored. Our functional approach to defragmentation of habitat encompasses different spatial concepts related to anthropogenic forest fragmentation and allows up to a 25-fold gain in cost-effectiveness for seismic lines restoration.

Using CFD to model the distortion of pollutant concentration signal at exhaust lines

The present study introduces a method for generating the distortion of species concentration signals within exhaust lines, employing Computational Fluid Dynamics (CFD) modelling instead of experimental techniques. Understanding distortion is important when e.g. tailpipe pollutant signals need to be correlated to engine operation patterns and related correction models need to be built. The approach was initially applied on a typical exhaust line geometry of a car, demonstrating the ability of CFD modelling to simulate the CO2 signal distortion from engine out to tailpipe, and was validated against laboratory measurements. Comparisons for variable operating points, between simulations and experiments, presented a good agreement with a deviation of up to 0.04 s in the time required for the signal to reach 50 % of its final output value (t50), and of up to 0.1 s in the rise time (t90-10). The methodology was applied to a vehicular exhaust line comprising tubing and buffer volumes, simulating catalysts or mufflers. This investigation aimed to identify the parameters that influence the distortion of CO2, revealing that inlet exhaust gas velocity can significantly impact CO2 distortion. Inlet temperature variations of ± 50 K produce a negligible deviation in t50 of ± 0.01 s for low inlet velocities and of ± 0.001 s for high inlet velocities. CFD is a useful tool to characterize pollutants signal generation within exhaust line configurations not limited to cars. Such a technique can be used to any mobile or stationary combustion system to study species concentration distortions caused by the individual components.

A novel method based on PSO algorithm and ANN for magnetic flux density estimation near overhead transmission lines

Abstract This paper introduces a novel method that leverages artificial neural networks to estimate magnetic flux density in the proximity of overhead transmission lines. The proposed method utilizes an artificial neural network to estimate the parameters of a mathematical model that describes the magnetic flux density distribution along the lateral profile for various configurations of overhead transmission lines. The training target data is acquired using the particle swarm optimization algorithm. A performance comparison between the proposed method and the Biot-Savart law-based method is conducted using an extensive test dataset. The resulting coefficient of determination and mean square error values demonstrate the successful application of the proposed method for a range of different spatial arrangements of phase conductors. Furthermore, the performance of the proposed method is thoroughly assessed on multiple test cases. The practical relevance of the proposed method is highlighted by contrasting its results with the field measurements obtained in the proximity of a 400 kV overhead transmission line.

Numerical Analysis and Design of a High‐Frequency Surface Acoustic Wave Transducer: Influence of Piezoelectric Substrates and IDTs Configurations

ABSTRACTThe development of SAW transducers requires a series of steps ranging from material selection and geometry design to the selection of fabrication techniques for their characterization and validation process. Here, we use the finite element method (FEM) to present a methodology and a detailed analysis of the design of SAW transducers in a delay line configuration. First, we simulate single‐finger and double‐finger configurations with different geometries and designs of IDTs on two piezoelectric substrates, LiNbO in 64 YX and LiNbO 128 YX orientation, to compare the simulation results with the analytical delta model and thereby validate the simulation process, presenting Root Mean Square Error (RMSE) values ranging from 10.79 dB to 16.42 dB. With the above, we performed a comparative analysis to determine the influence of piezoelectric material and IDT configuration by studying a specific transducer design made to operate at a resonance frequency of 97.02 MHz. We compared identical designs on 128 YX and 64 YX orientations of LiNbO with single and double‐finger configurations and added the comparison with the SPUDT configuration. We observed the best results for the single‐finger IDT configuration in 128 YX LiNbO orientation compared to the other variants through its insertion loss level of −7.29 dB, its average sidelobe level of −18.63 dB, and its average transition band slope for the main lobe of 15.09 dB/MHz. The results guide new researchers or students in expanding the use of numerical tools in designing SAW transducers and SAW devices.

The Influence of the Assembly Line Configuration and Reliability Parameter Symmetry on the Key Performance Indicators

In the context of the demand for mass customization of products, a trade-off between highly efficient automated systems and flexible manual operators is sought. The linear arrangement of workstations made it possible to divide the process into many simple operations, which increases production efficiency, but also results in an increase in the number of workstations and a significant extension of the line. A human operator is usually treated as a quasi-mechanical object, and a human error is considered, similarly, as a failure of a technical component. However, human behavior is more complex and difficult to predict. A mathematical model of a new production organization is presented, including dividing the traditional production line into shorter sections or replacing the serial assembly line with a U-line with cells. Moreover, the reliability of operator and technical means are distinguished. Work-in-progress inventories are located between line sections to improve system stability. The stability of the assembly line is examined based on the system configuration and probabilistic estimates of human failure. The influence of the symmetry of reliability parameters of people on key performance indicators (KPI (headcount), KPI (surface) and KPI (Overall Equipment Effectiveness) is examined. KPI (solution robustness) and KPI (quality robustness) are also presented in order to evaluate the impact of a disruption on the assembly line performance. New rules for assigning tasks to stations are proposed, taking into account the risk of disruptions in the execution of tasks. For comparison of assembly problems, heuristic methods with newly developed criteria are used. The results show the impact of symmetry/asymmetry on assembly line performance and an asymmetric distribution of manual assembly times that is significantly skewed to the right due to human errors. On the assembly line, the effects of these errors are cumulative and lead to longer assembly times and lower KPIs.

Impact of Intersection Left Turn Guide Lines Configuration on Novice Drivers’ Behavior

Novice drivers often face challenges such as misjudgment, inappropriate steering control, distraction, and insufficient speed control when making left turns at intersections, leading to safety hazards. Installing intersection guide lines offers a solution by providing clear path directions, mitigating safety concerns associated with novice drivers’ left-turn actions. This study explored the impact of intersection guide line configurations on the driving behavior of novice drivers during left turns, utilizing large, medium, and small typical intersections to create six categories of left-turn simulation scenarios in a driving simulator. Data on vehicle trajectory, steering angle, steering speed, and eye-tracking were collected and analyzed. The study revealed that guide line arrangement significantly influences novice drivers’ left-turning behavior, enhancing path guidance while reducing trajectory and steering angle fluctuations, speed variations, and driver attention dispersion. This improvement in stability is particularly notable as intersection size and the number of left-turn lanes increase. The study’s findings offer robust theoretical support and guidance for the development and widespread adoption of intersection guide lines.

Numerical Analysis and Health Implications of Electric Fields from High Voltage Overhead Transmission Lines for Safety and Design Optimization

This paper calculates and analyses electric fields generated by high-voltage overhead power transmission lines. These fields have significant implications for safety and design considerations. The study utilises a numerical technique to determine the electric field distribution in regions containing multiple charges. Based on this method, a computer program is developed to calculate the electric field profile at ground level and two meters above ground level for both 400 kV overhead power lines. The results demonstrate the method's effectiveness in accurately computing the electric field intensity for various line configurations, making it applicable to any power line design. The paper also highlights the potential health effects associated with exposure to these electric fields, including leukaemia, breast cancer, cognitive impairments, and reproductive consequences. The proposed method can also be applied to other transmission lines, providing valuable insights into health considerations. The accuracy of the computation methods is validated using the finite element analysis method. This research contributes to the understanding and assessing ground-level electric fields, offering industry professionals and researchers valuable insights into the safety and design of power transmission systems.

Tribological behaviour of laser textured Ti3AlV 2.5V alloy under simulated body fluid

The use of lasers to fabricate micro-textures on the surface of medical implants is an effective method to improve their bio-tribological properties. In the present study, three distinct configurations of micro-textures, namely, co-axial circles, hexagon, and line with varying spacing of 300 µm, 400 µm, and 500 µm, were fabricated on Ti3Al2.5V alloy using Nd:YAG fibre lasers. The influence of micro-textured geometries on microhardness, coefficient of friction (COF), and wear rate was estimated. The tribological properties of the polished and textured samples were investigated using a linear reciprocating tribometer against silicon nitride (Si3N4) balls under simulated body fluid (SBF) lubricant. Orthogonal results indicate that the co-axial circles with a spacing of 305 µm prove to be the most efficient in enhancing the tribological performance of textured surfaces. This configuration demonstrates a significant improvement, with a 33.62 % reduction in friction coefficient and a 61.81 % reduction in wear rate compared to polished samples. The decrease in spacing appears to enhance the anti-friction and anti-wear properties of the textured surfaces. The working mechanism behind the reduction in the friction coefficient and wear rate lies in the capacity of the textures to trap particles.