•A LSTM-based time series model is proposed for liquid cargo traffic prediction.•Missing value handling techniques are used to improve prediction performance.•Dependencies between different types of ...liquid cargo traffic are considered.•The proposed LSTM-based model overcomes a vanishing gradient problem as well.•Performance of the proposed LSTM-based model is compared with ARIMA and VAR.
The authors propose a time series model that predicts future values of various types of liquid cargo traffic based on long short-term memory (LSTM), a deep learning technique. Existing liquid cargo traffic prediction models are based on traditional time series models, such as autoregressive integrated moving average (ARIMA) and vector autoregression (VAR). Some of these models, which do not consider linear dependencies among the values of different types of liquid cargo traffic, have limitations on their prediction performance, because the values of different types of liquid cargo traffic are dependent on one another. These models’ prediction performance are also limited due to the problem of vanishing gradients, which hinders the learning of long-range time series records. Missing values that exist on real-world liquid cargo traffic records reduce prediction performance as well. The proposed LSTM-based time series model handles missing values on liquid cargo traffic records and predicts future values of liquid cargo traffic. In addition, additional indices, such as inflation rates, exchange rates for dollars, GDP values, and the international prices of oil, are used to improve prediction performance. A case study involving real-world liquid cargo traffic records at the Port of Ulsan, Republic of Korea, for 216 months is used to validate prediction performance of the proposed LSTM-based prediction model compared with traditional ARIMA-based and VAR-based prediction models.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Display omitted
Manipulating droplet transportation without inputting work is desired and important in microfluidic systems. Although the creation of wettability gradient on surfaces has been ...employed to achieve this goal, the transport distance is very limited, hindering its applications in long-term operations.
Here, we show that programming long-ranged transport of droplets on surfaces can be achieved by the addition of trisiloxane surfactants and the creation of deep grooves. The former provides Marangoni stress to actuate the droplet motion and also reduces the inherent contact line pinning. The latter acts as a railing to guide the motion of surfactant-laden droplets to follow various layouts with geometric features of roads.
It is found that the droplets with microliters can move over 20 cm. This work-free method is applicable to a variety of substrate materials and liquids. By using self-running shuttles, a convenient platform for liquid cargos transport is developed and demonstrated. Moreover, the coalescence of cargos carried by different shuttles is accomplished in a three-branch layout, revealing new droplet microreactors.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The continuous growth in the volume of liquid cargoes, transported by sea, leads to increase of tankers’ size and to implementation of appropriate shore facilities, which have to meet the relevant ...environmental requirements. In order to ensure safety during loading and discharging operations in shore terminals, it is necessary to make an assessment on the level of potential risk in port and onboard the vessel and to take all necessary steps to reduce the possibility for environmental impacts and occurrence of an accident especially when performing transfer operations to/from ships. The article presents some constructive decisions for building of shore tanks and their application for storage and transfer of petroleum products. The measures for the safe performing of the cargo operations are systematized after discussing of specifics by performing of all processes connected with loading or discharge. The precautions are defined in three critical points of action - operation on vessel systems, transportation of cargo using shore facilities and storage in tanks.
ObjectiveThis paper focuses on using reinforcement learning-based automatic generation technology to generate loading and unloading schemes for the liquid cargo tanks of oil tankers. MethodsUsing the ...cargo capacity of an actual operating oil tanker as the input and the loading rates of the cargo tank and ballast water tank as the targets, an intelligent agent and environment are built based on Unity ML-Agents. The agent is trained using the PyTorch framework, and a reward function calculation method that comprehensively considers the loading time and changes in the trim amplitude is proposed. Finally, example analysis is carried out to validate the feasibility of the proposed method. ResultsThe results show that the trained agent can learn effective strategies for achieving the autonomous generation of liquid cargo tank loading schemes. ConclusionsThis study proves that it is reasonable and feasible to apply reinforcement learning to solve the problem of the autonomous generation of liquid cargo tank loading schemes under multi-objective conditions.
Tank cleaning is an important work in the operations of liquid cargo tankers, which plays an important role in connecting the loading and unloading of cargoes during two voyages. This paper ...summarises the research on safe and efficient tank cleaning for liquid cargo tankers. It first introduces the basic process of tanker cleaning operations of liquid cargo tankers and the relevant requirements of convention and standard. Then, from two aspects of the safety and timeliness of tank cleaning, the main factors affecting the safety and cleaning effectiveness of tank cleaning operations of liquid cargo tankers are summarised, and the research status and effects of these influencing factors are analysed and summarised respectively. Finally, combined with the current research status, the challenges and development prospects of safe and efficient tank cleaning operations are proposed. It has implications for researchers in conducting future research on tank cleaning of liquid cargo tankers.
Full text
Available for:
BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
ObjectiveCargo loading and unloading plan generation time and safety evaluation have a great influence on the handling efficiency. To this end, this paper introduce weight coefficient searching ...genetic algorithm into the plan generation. MethodsLoading safety status mainly involves draft limitation, intact stability checking, hyrostatic strength checking and compatibility between the generated loading and unloading plan and preset process. In this study, a non-deterministic polynomial and corresponding optimization objective functions are established to solve the loading and unloading scheme generation problem of liquid cargo carriers. The weight of each influence factor in the objective function is changed and recorded in sequence to form an optimal objective function cluster. The optimal solution of each member in the cluster is then carried out through an elitist preservation genetic algorithm in order to provide an optimal solution set. On this basis, a comparison is made with the loading and unloading plan of a very large crude oil carrier (VLCC) generated by the linear fitting methodResultsThe ship draft status is more consistent with the target, and the stability state is obviously better than that of the user preset plan in each loading/unloading step generated by this algorithm. ConclusionThe weight coefficient searching genetic algorithm based on elitist preservation proposed in this paper can improve the accuracy and reliability of the liquid cargo carrier loading sequence.
Systemic numerical studies have been carried out to analyze the influence of the main traffic parameters at the moment of braking of a regular column of tank trucks in order to determine the maximum ...values of the dynamic impact on transport facilities. A refined design scheme of a unified oscillatory system, a mathematical model developed by the authors, and a unified numerical algorithm for nonlinear oscillations are used. The computer complex in the Simulink simulation package for dynamic and event-driven systems of the MATLAB system was adapted to solve the posed problem on the basis of expert models developed earlier by the authors. A parametric analysis of the impact level of tank truck columns on transport facilities when changing the mode of movement is carried out according to the results of computational experiments. When simulating the passage of a vehicle column, the parameters of the movement of the column, the position of the first vehicle on the transport facility at the time of the start of braking, as well as the characteristics of an individual tanker in the column were varied. The degree of influence of each parameter is determined, and their combinations in which there is a danger of excess dynamic impact of a moving load on transport facilities are identified. The expediency of separating such columns into a special class of moving load and the need to amend the regulatory documents are shown.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
This reprint collected the cutting-edge developments of CFD in the area of marine science and technology. CFD methods including novel numerical algorithms, advanced treatments of solving procedures, ...parallel acceleration techniques, and the utilization of CFD for fluid–structure interaction, wave modeling, ship dynamics, etc., are included. The audience of this reprint can be researchers and engineers in the area of marine science and technology.
With the development of large liquid cargo ships, liquid tank sloshing has gradually become a hot research topic in the area of shipping and ocean Engineering. Liquid tank sloshing, characterized by ...strong nonlinearity and randomness, not only affects the stability of the ship but also generates a huge impact force on the wall of the tank. To further investigate liquid tank sloshing, a comprehensive review is given on the research process of the most focused subjects of liquid sloshing. Summarizing the existing research will help to identify issues in the current field and provide useful references. The methods for investigating sloshing, the research progress and the situations worldwide are discussed. The advantages and defects of experiments and numerical simulations are also explored. The problems which need to be explored in the future are subsequently proposed.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
The transportation of bulk or liquid cargo is crucial for ensuring the delivery of such cargo to areas lacking well-established infrastructure or favorable natural conditions. These areas may lack ...sufficient rail or air transport accessibility, or may not have suitable embankments along rivers, lakes or seas with appropriate loading and unloading facilities. Regarding distinctive characteristics, we would like to emphasize the following: (1) Efficient freight accessibility without the need for more infrastructure that is tailored to the existing natural circumstances; (2) An efficient and cost-effective mode of transportation for the movement of small quantities of goods; (3) The cargo philosophy is designed to meet customer expectations by providing a convenient and personalised service that is focused on delivering goods directly to their door. This research employed theoretical methodologies to characterize the primary force exerted by vehicles in the transportation of bulk and liquid commodities (the relationship between centrifugal force and speed and the relationship between the center of gravity and speed). Furthermore, by using expert assessment, the significance indicators pertaining to the individual criteria impacting the transportation of bulk and liquid cargoes were ascertained, along with the identification of their interrelationships (comparison of the different forces in the transportation process of bulk and liquid cargoes, comparison of the criteria of centrifugal force in the transportation process of bulk and liquid cargoes, comparison of the dangerous factors in the transportation process of bulk and liquid cargoes, comparison of the critical level of tank filling in the transportation process of bulk and liquid cargoes, and comparison of the factors that can affect the dynamics of a vehicle in the transportation process of bulk and liquid cargoes).
PDF
