Large Container Research Articles

A Proposed Design Technique for Recycling of Very Large Container Ship

A Proposed Design Technique for Recycling of Very Large Container Ship

Nursery production, acclimatization, and orchard transplantation of Argania spinosa: Evaluating the impact of costs and plant age

The depletion of the argan area over time underscores the importance of enhancing the quality of argan seedlings to support regeneration. Key factors such as seedling age and nursery techniques including shade, substrate, and container play a crucial role in improving seedling quality and ensuring successful transplantation. Our study assessed the impact of seedling age, shading, substrate composition, and container volume on argan seedling production during the nursery phase and their influence in the transplantation phase. The findings revealed 40% shade covering in 12- and 18-month-old seedlings exhibited the most growth potential, while unshaded compartments were suitable for 6-month-old seedlings. Substrates S1, S3 and S6 respectively, resulted in the highest quality seedlings overall, with S1 being the most effective for 6-month-old seedlings, and S3 and S6 showing more impact for 12- and 18-month-old seedlings. Furthermore, the use of larger containers contributed to the production of high-quality seedlings. Field results showed lower mortality rates across different seedling ages (3.1% to 9.3%) and revealed no significant difference among the combinations, except for seedlings produced under 40% shade, where the S3C3 combination followed by S1C2 in the 6-month nursery production period demonstrated the highest relative growth rate in shoot length. The relative growth rate in diameter reported its highest value in the S1C2 combination of 18-month and 6-month-old seedlings. A cost benefit analysis was carried out, which revealed that the cost-effective combination was S1C2, followed by S3C3 for 6-month-old nursery age under the 40% compartment.

The Field Assessment of Quiescent Egg Populations of Aedes aegypti and Aedes albopictus during the Dry Season in Tapachula, Chiapas, Mexico, and Its Potential Impact on Vector Control Strategies.

Although integrated management and control programs implement intense control measures for adult, pupal, larval, and breeding sites during outbreaks, there is a lack of studies to understand the role of the vector egg stage in disease dynamics. This study aimed to assess the dry season quiescent Aedes aegypti and Aedes albopictus egg populations in houses and backyards in Tapachula, southern Mexico. Two hundred and fifty ovitraps were placed in 125 homes in the Las Americas neighborhood. A total of 7290 eggs were collected from 211 (84.4%) ovitraps. Only 5667 (77.7%) hatched under insectary water immersion and food supply conditions, with 4031 (71.1%) identified as Ae. aegypti, and 1636 (28.8%) as Ae. albopictus, respectively. The remaining 1623 (22.3%) did not hatch due to Delayed Hatching and/or quiescence tropical stage. Eighty-three larval containers were sampled with desiccated eggs during the dry season; most of them were described as trash waste because larvicides are only used for larger containers of 5-10 L. Evolutionary characteristics for the two species including partial egg hatching, ambient-regulated quiescence, the ability of the embryo to survive for a more extended period intra-seasonally, the egg sticking to inner container walls, demands urgent operational research to achieve successful egg-proof larval container methods.

Toward green container liner shipping: joint optimization of heterogeneous fleet deployment, speed optimization, and fuel bunkering

AbstractContainer liner shipping companies, under the international shipping carbon reduction indicators proposed by the International Maritime Organization, must transform two key aspects: technology and operations. This paper defines a green liner shipping problem (GLSP) that integrates the deployment of a heterogeneous fleet, speed determination, and fuel bunkering. The objective is to achieve low‐carbon operations in liner shipping, taking into consideration the diversification of power systems, the use of alternative fuels in ships, and the continuous improvement of alternative fuel bunkering systems. For this purpose, we present a bi‐objective mixed integer nonlinear programming model and develop two methodologies: an epsilon‐constraint approach and a heuristic‐based multi‐objective genetic algorithm. We validate the effectiveness of our model and methods through a case study involving container ships of various sizes deployed on intra‐Asian short sea routes by SITC International Holdings Co., Ltd. The experimental results highlight the crucial role of dual‐fuel (DF) ships in the pursuit of low‐carbon strategies by liner companies, with liquefied natural gas and ammonia DF ships being the most widely used. Additionally, fuel cell (FC) ships, particularly those powered by ammonia and hydrogen, demonstrate significant carbon reduction potential. Furthermore, ships with larger container capacities have a greater cost advantage. For the GLSP, speed determination is an auxiliary decision, and the lowest speed is not necessarily the optimal choice. Decision‐makers must carefully balance competing economic and carbon emission reduction objectives, as deploying more alternative fuel ships may increase fuel bunkering and fuel consumption, resulting in a higher total operating cost.

Coupling a time-domain code with a RANS solver for slamming analysis

ABSTRACT A time domain hydroelastic code (TD) based on strip theory is two-way coupled with a Reynolds Averaged Navier−Stokes (RANS) solver to capture the bottom slamming effects on ships. The study is conducted on an Ultra Large Container Ship (ULCS). The methodology considers the hull’s flexibility and analyses longitudinal bending in head seas. Ship motions are calculated using a body non-linear time-domain method based on strip theory. The equations of motion are solved, and time integration is performed using the fourth-order Runge–Kutta method. When a slamming event is identified, the TD code activates a RANS solver to determine the bottom slamming force. The simulations are conducted under extreme sea conditions, and the hull experiences springing and whipping responses. The numerical results of vertical bending moments are compared with experimental data. The bottom and bow flare slamming are identified from the simulations.

Bilge pumping performance for cargo holds of large container ships

Bilge pumping performance for cargo holds of large container ships

Recycling Pesticide Plastic Containers in Indonesia: An Evaluation of Technical, Economic, and Regulatory Impact Feasibility

This study explores the feasibility of recycling pesticide plastic packaging in Indonesia, focusing on technical, economic, and regulatory aspects. Technical feasibility analysis highlights challenges in material composition and pesticide residue removal, emphasizing the effectiveness of a cleaning process to ensure safety and quality of recycled materials. Economically, the study demonstrates significant cost savings when incorporating at least 40% recycled material into new packaging, enhancing market competitiveness. The regulatory analysis emphasizes the recommendation to the Indonesian government to reclassify waste pesticide containers from hazardous to non-hazardous materials following the validation of the triple rinsing trial’s effectiveness in removing pesticide residue. Reclassifying the containers as non-hazardous will reduce transportation costs from the source locations, such as plantations or farming areas, to the waste processing plant, thereby improving the economic feasibility of the pesticide plastic container recycling. Recommendations include conducting production trials with larger container sizes and adjusting the recycled material percentage, as well as exploring performance-enhancing additives for recycled plastics. Industries are advised to align with regulations by adopting best recycling practices and establishing robust compliance processes. Strengthening Extended Producer Responsibility (EPR) schemes and supporting advanced recycling infrastructure development are critical steps. These measures will improve the efficiency and effectiveness of recycling programs, ensuring regulatory compliance and promoting sustainable waste management. The study concludes that recycling pesticide plastic packaging is feasible and beneficial, provided that technical and economic challenges are effectively addressed with at least 40% recycled material content. The economic viability of recycling pesticide plastic containers will be further enhanced if the Indonesian government reclassifies the waste containers as non-hazardous, after triple rinsing process, thereby reducing transportation costs.

Towards a reliable method for extrapolation of propulsion performance for vessels with twin-crp-pod system

The study presents power performance prediction of an Ultra Large Container Ship (ULCS) with hybrid twin-crp-pod propulsion system. Twin crp-pod propulsion system is a combination of three concepts: twin screw, contra-rotating propellers (crp) and conventional shaft propellers with pod propulsors behind. The presented study shows the current extrapolation method for crp propulsion systems and tries to point out its weaknesses. As a case study, a 400 m ULCS has been investigated in full-scale and in model scales of 24 and 37.416. The analyses were carried out for all scales with use of CFD numerical methods and for the scale of 37.416 based on towing tank tests. All the results have been extrapolated with the same method and results have been compared. The investigations clearly show differences in delivered power prediction extrapolated from towing tank results giving the maximum value and from CFD made to scale of 24 the minimum value. Finally, conclusions on possible sources of differences, including the numerical and analytical methods are presented.

Clash of mosquito wings: Larval interspecific competition among the mosquitoes, Culex pipiens, Aedes albopictus and Aedes aegypti reveals complex population dynamics in shared habitats.

Globalisation, climate change and international trade are the factors contributing to the spread of Aedes albopictus (Diptera: Culicidae) and Ae. aegypti into new areas. In newly invaded habitats, these non-native species can serve as arbovirus disease vectors or increase the risk of disease spill over. These mosquitoes continue to emerge in new areas where they have or will have overlapping ranges with other resident mosquito species. The study investigates how invasive Aedes mosquitoes compete with the native Culex pipiens in Türkiye, which might affect the overall mosquito population dynamics and disease transmission risks. Both Aedes species exhibited contrasting responses to interspecific competition with Cx. pipiens. While Ae. albopictus suffers reduced emergence primarily in larger containers with abundant food, Ae. aegypti surprisingly thrives in mixed cultures under all food conditions. Adult Cx. pipiens emergence drops by half against Ae. albopictus and under specific conditions with Ae. aegypti. Competition influences mosquito size differently across species and life stages. Culex pipiens females grow larger when competing with Ae. aegypti, potentially indicating resource advantage or compensatory strategies. However, Ae. albopictus size shows more nuanced responses, suggesting complex interactions at play. Understanding how invasive and native mosquitoes interact with each other can provide insights into how they adapt and coexist in shared habitats. This knowledge can inform effective control strategies. The study highlights the differential responses of invasive Aedes species and the potential for managing populations based on their competitive interactions with the native Cx. pipiens. It can contribute to improved monitoring and prediction systems for the spread of invasive mosquitoes and the associated disease risks.

Research on temperature distribution in container ship with Type-B LNG fuel tank based on CFD and analytical method

The liquefied natural gas (LNG) fuel tank in a large container ship is loaded with liquid LNG at an ultra-low temperature (-163°C), there is a significant temperature difference in the cargo hold area where the entire fuel tank is located, which will have an important impact on the steel grade design and structural safety of the cargo tank in container ship. This paper develops two heat transfer models using Computational Fluid Dynamics method (CFD method) and an analytical method to analyze the temperature distribution in a large container ship equipped with Type-B LNG fuel tank. These models incorporate the arrangement and heat transfer characteristics of LNG fuel tanks. The temperature field analysis is conducted under typical the environmental conditions specified in the Code for the Construction and Equipment of Ships Transporting Liquefied Gas in Bulk (IGC Code) and the United States Coast Guard Code (USCG Code), based on the CFD method and the analytical method, and the results of temperature field distribution are compared. Additionally, a parametric analysis of the hull temperature field is further carried out, the results show that the thermal conductivity of the insulation layer in LNG storage tanks and the types of the loaded liquid cargo have a limited impact on the final temperature field distribution in hull structure. However, the selection of steel grade in the local structure of the cargo hold, especially in the inner hull part, may lead to significant changes.

X-ray computed tomography for 3D crystallization monitoring: A use case with paracetamol

This work highlights the capabilities and limits of X-ray computed tomography in crystallization monitoring through a use case involving paracetamol as the solute, recrystallized from ethanol, methanol, or a mixture of both. The cooling crystallization operation was set up in two different containers, prepared with cotton yarns stretched vertically, acting as linear nucleation sites that immobilize the grown crystals in the recording area. The largest container (10 mL test tubes) allowed the acquisition of a larger number of crystals (up to 300 particles) for a more appropriate bulk analysis. The smallest container (5 mL pipette tips) allowed for a finer resolution of the recorded solid phase at the expense of a reduced recording volume. Crystallization was monitored in terms of the number of individual crystals, their size, and the overall volume, thus leading to the nucleation and growth rates, and solid-phase production rate. The main benefit of X-ray computed tomography is in the 3D analysis of the reconstructed solid phase. The crystal habit of paracetamol form I was predicted using force-field modeling. The predicted habit was in great accordance with the reconstructed solids, confirming the polymorphic form. Furthermore, face-specific growth rates of reconstructed crystals were measured, paving the way for a novel approach to the investigation of crystal-solvent interactions.

Efficient use of collision detection for volume maximization problems

This paper proposes improved local search heuristics based on collision detection for solving volume maximization problems, with a particular focus on single item volume maximization. The objective is to find the biggest item of a predefined shape that can be extracted from a larger container. Both the item and the container are three-dimensional objects and can have irregular shapes. Our goal is to find high-quality solutions for these problems within a reasonable amount of time, even for complex instances where the object and container are represented by thousands of triangles. We consider an approach where the position and orientation of an item are optimized heuristically, while the scale of the item is maximized using a fast inflation procedure. This inflation procedure uses bisection search and collision detection to determine the largest possible scale that satisfies all geometric constraints for a given position and orientation of the item within the container. We introduce improvements to this approach to reduce the required amount of geometric computations required. Finally, we compare our results against a matheuristic method from the literature on an expanded data set, which shows the improved collision detection approach is more than 100 times faster and highlights the impact of our improvements.

Process Planning for Large Container Ship Propeller Shaft Machining Based on an Improved Ant Colony Algorithm

To accommodate the production and manufacture of complex and customized marine components and to avoid the empirical nature of process planning, machining operations can be automatically sequenced and optimized using ant colony algorithms. However, traditional ant colony algorithms exhibit issues in the context of machining process planning. In this study, an improved ant colony algorithm is proposed to address these challenges. The introduction of a tiered distribution of initial pheromones mitigates the blindness of initial searches. By incorporating the number of iterations into the expectation heuristic function and introducing a ‘reward–penalty system’ for pheromones, the contradictions between convergence speed and the tendency to fall into local optima are avoided. Applying the improved ant colony algorithm to the process planning of large container ship propeller shaft machining, this study constructs a ‘distance’ model for each machining unit and develops a process constraint table. The results show significant improvements in initial search capabilities and convergence speed with the improved ant colony algorithm while also resolving the contradiction between convergence speed and optimal solutions. This verifies the feasibility and effectiveness of the improved ant colony algorithm in intelligent process planning for ships.

Relationship Between Product Features and the Prices of e-Cigarette Devices Sold in Web-Based Vape Shops: Comparison Study Using a Linear Regression Model.

Open-system electronic cigarette (EC) product features, such as battery capacity, maximum output wattage, and so forth, are major components that drive product costs and may influence use patterns. Moreover, continued innovation and monitoring of product features and prices will provide critical information for designing appropriate taxation policies and product regulations. This study will examine how product features are associated with the prices of devices sold in web-based vape shops. We draw samples from 5 popular, US-based, web-based vape shops from April to August 2022 to examine starter kits, device-only products, and e-liquid container-only products. We implemented a linear regression model with a store-fixed effect to examine the association between device attributes and prices. EC starter kits or devices vary significantly by type, with mod prices being much higher than pod and vape pen prices. The prices of mod starter kits were even lower than those of mod devices, suggesting that mod starter kits are discounted in web-based vape shops. The price of mod kits, mod device-only products, and pod kits increased as the battery capacity and output wattage increased. For vape pens, the price was positively associated with the volume size of the e-liquid container. On the other hand, the price of pod kits was positively associated with the number of containers. A unit-based specific tax, therefore, will impose a higher tax burden on lower-priced devices such as vape pens or pod systems and a lower tax burden on mod devices. A volume- or capacity-based specific tax on devices will impose a higher tax burden on vape pens with a larger container size. Meanwhile, ad valorem taxes pegged to wholesale or retail prices would apply evenly across device types, meaning those with advanced features such as higher battery capacities and output wattage would face higher rates. Therefore, policy makers could manipulate tax rates by device type to discourage the use of certain device products.

Environmental Justice and Systems Analysis for Air Quality Planning in the Port of Oakland in California.

Many frontline communities experience adverse health impacts from living in proximity to high-polluting industrial sources. Securing environmental justice requires, in part, a comprehensive set of quantitative indicators. We incorporate environmental justice and life-cycle thinking into air quality planning to assess fine particulate matter (PM2.5) exposure and monetized damages from operating and maintaining the Port of Oakland, a major multimodal marine port located in the historically marginalized West Oakland community in the San Francisco Bay Area. The exposure domain for the assessment is the entire San Francisco Bay Area, a home to more than 7.5 million people. Of the more than 14 sources included in the emissions inventory, emissions from large container ships, or ocean-going vessels (OGVs), dominate the PM2.5 intake, and supply chain sources (material production and delivery, fuel production) represent between 3.5% and 7.5% of annual intake. Exposure damages, which model the costs from excess mortalities resulting from exposure from the study's emission sources, range from USD 100 to 270 million per annum. Variations in damages are due to the use of different concentration-response relationships, hazard ratios, and Port resurfacing area assumptions. Racial and income-based exposure disparities are stark. The Black population and people within the lowest income quintile are 2.2 and 1.9 times more disproportionately exposed, respectively, to the Port's pollution sources relative to the general population. Mitigation efforts focused on electrifying in-port trucking operations yield modest reductions (3.5%) compared to strategies that prioritize emission reductions from OGVs and commercial harbor craft operations (8.7-55%). Our recommendations emphasize that a systems-based approach is critical for identifying all relevant emission sources and mitigation strategies for improving equity in civil infrastructure systems.

Analysis of the Impact of Large Container Ships on Port Capacity

Facing the fierce competition in the shipping market, major container liner companies are constantly increasing the scale of container ship construction in pursuit of scale effect, and the trend of large-scale development of container ships is increasingly obvious. The enlargement of container ships not only intensifies the competition of shipping companies, but also brings profound changes to the port's facilities and equipment. This paper analyzes the development process, background and reasons of the large-scale container ships, as well as the future development trend of large-scale ships. The qualitative and quantitative method was used to analyze the current status of ship enlargement on the development status. Through the corresponding data and cases, combined with the current rise of international trade protectionism and the global spread of new pneumonia, the impact of ship enlargement on port development was analyzed with a view to the port Development provides corresponding theoretical references and suggestions.

The impact of container call size - evidence from simulation modelling

We present an analysis of the impact of large container ship call sizes on the operational efficiency of container terminals as well as on hinterland modes of transport. We use standard container terminal simulation software, that can represent a realistic terminal operation. We include dynamic crane productivity, arrival time uncertainty, and deepsea vessel prioritisation in our model.Our experiments investigate the impact of introducing larger call sizes of container ships, increasing the uncertainty in arrival times of deepsea ships, and the impact of the phenomenon of split calls that are employed by the largest container ships in certain regions in the world. We differentiate between the impact on terminal operations, land-based hinterland traffic, and hinterland traffic over water, through barges and feeder vessels.Our results show that introducing large ships with large container call sizes comes with benefits and drawbacks. Benefits can be found in planning advantages for both the deepsea ships and barges and feeders handled in the terminal. Drawbacks occur as a result of operational peaks in subsystems such as the quay cranes, the stack and the land side gates. Higher uncertainty deteriorates the performance of the terminal, but the impact on the hinterland modes of transport is greater than on the large deepsea vessels. The impact of the split call is that it brings all the disadvantages of large vessels, but none of the benefits.Our analysis shows the operational impact of large call sizes on terminal operations and hinterland transport operations, based on container terminal simulations with a higher degree of realism than previous work. In addition, we offer, for the first time, insights in the impact of split calls of container ships at container terminals.

Black-box modeling of ship maneuvering motion using multi-output least-squares support vector regression based on optimal mixed kernel function

Black-box modeling has been widely used to predict ship maneuvering motion. A novel black-box modeling approach using optimal mixed kernel multi-output least-squares support vector regression (MMLSSVR) based on the artificial hummingbird algorithm (AHA) is proposed in this paper. To improve the performance of the MMLSSVR model, a mixed kernel function that combines a radial basis function and a polynomial kernel function to capture both global and local properties is proposed. The optimal hyper-parameters of the mixed kernel function are determined by the AHA, which employs the linear combination of the mean square error and the determinant of error covariance as the objective function to balance between prediction accuracy and stability. The performance of the proposed method is evaluated using SR108 large container ship data. The experimental results demonstrate that the proposed MMLSSVR model achieves desirable prediction accuracy and strong generalizability for ship maneuvering motion modeling.

Real-time prediction of wave-induced hull girder loads for a large container ship based on the recurrent neural network model and error correction strategy

Real-time acquisition of wave-induced hull girder loads of a sailing ship will help the captain make reasonable decisions, which is of great significance for improving the safety of the ship's navigation. This paper investigates the real-time prediction method of hull girder loads based on the Recurrent Neural Network (RNN) model and error correction strategy. Firstly, taking the vertical bending moment, horizontal bending moment, and torsional moment at the mid-ship position of a large container ship as examples, corresponding neural network prediction models are established through parameter influence analysis. Secondly, various sea state conditions are used to verify the feasibility of established network prediction models to predict the hull girder loads in real-time. The VBM prediction model performs better than the TM prediction model and HBM prediction model, and the errors of the TM prediction model and HBM prediction model are slightly larger in some cases. Lastly, an improved prediction model based on an error correction strategy is proposed to improve the prediction accuracy of the neural network prediction model, and the adequate performance of the error correction strategy is discussed.

Nonlinear PID Control for Automatic Docking of a Large Container Ship in Confined Waters Under the Influence of Wind and Currents

This study addresses the challenges of maneuvering a large container ship in confined waters under the influence of wind and currents. The proposed guidance, navigation, and control system presents a novel combination of modeling methodologies, control allocation techniques, and nonlinear control systems theory. We consider a docking scenario through a simulation of a realistic, narrow harbor accommodating area-specific currents and global wind forces. Control allocation is solved by utilizing detailed models of the actuators and hydrodynamics in a mixed-integer-like solution for optimal thrust allocation, and an inverse mapping to the control inputs. Furthermore, our approach introduces a modified Wageningen B-Series model, that is capable of modeling propellers with negative pitch dynamics. The complexity of safely docking in environments like the Antwerp harbor, where wind and currents pose significant risks, is tackled using a nonlinear PID control system integrated with Line-Of-Sight (LOS) guidance. This enables precise maneuvering of a fully actuated Roll-On/Roll-Of vessel to its docking position and orientation. Given that few studies on automated docking holistically address the intricate challenges of complex harbor environments and the concurrent impact of multiple external forces, our work proposes a comprehensive solution based on an integrated combination of guidance, navigation, and control systems.