bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vulnerability of Ship with a Large Breadth to Draught Ratio Against Excessive Acceleration Criteria
Authors: Paroka D. , Muhammad A.H. , Rahman S. , Assidiq Fuad Mahfud 
Published: June 2023

Abstract
A ship having a large breadth and small draught may have a large metacentric height. Therefore, the ship could be vulnerable to the excessive acceleration criteria. In order to investigate the vulnerability, an Indonesian ro-ro ferry with breadth to draught ratio of 5.31 was used to apply the criteria. The lateral acceleration and the long-term probability index with limited scatter wave data of International Maritim Organization were calculated for passenger or crew accommodation in full loading condition. The calculation was conducted for variation of metacentric height using the JONSWAP spectrum to modelled irregular wave. The results show that the maximum vertical distance from the roll axis to comply with the criteria level 1 was 8.7% of ship breadth. The metacentric height comply with the criteria level 1 for the passenger or crew accommodation was 1.4 metres corresponding to 8.7% of ship breadth. The maximum wave height comply with the criteria level 2 was 5 metres. These results show that the excessive acceleration criteria can be used to assess stability of a ship with large ratio between breadth and draught. The vertical distance from the roll axis has more significant effect on the lateral acceleration than the metacentric height.
Effect of debonding damage on transient dynamic response on stern ramp door of passenger ship 6311 GT
Authors: Tuswan Tuswan , Amiruddin Wilma , Yudo Hartono , Prabowo Aditya Rio , Anjasmara Haikal 
Published: June 2023

Abstract
The sandwich, as an advanced material, increases innovation in the field of ship construction. One of the applications is on the ramp door structure. The characteristics of sandwich material which are light and strong, are the main reasons for the application of this material. However, sandwich material also has drawbacks, one of which is debonding damage, where the bond between the face and core is released. This damage can affect the structure’s stiffness, which impacts reducing the strength of the structure on the ramp door. The effect of debonding is identified by performing numerical tests using finite element software. This test aims to identify the ramp door’s dynamic response due to the debonding damage’s influence. This research uses finite element software with an explicit dynamics method to determine the dynamic response of stress and displacement due to loading on the ramp door. The results of testing with finite element software show that an increase in the ratio of debonding damage causes the amplitude of the dynamic response to increase when subjected to transient loading.
Experimental Study on Hydrodynamic Aspects of Turbine which Convert Hydrokinetic and Potential Coastal Wave Energy
Authors: Rahuna Daif , Erwandi  , Kasharjanto Afian , Suyanto Eko Marta , Mintarso Cahyadi Sugeng Jati 
Published: June 2023

Abstract
Currently, the exploration of ocean renewable energy sources was mostly carried out to obtain optimal results and low cost. The waves that arrive on the beach consist of both potential energy where the water surface moves up and down and hydrokinetic energy where the volume of water comes and goes into the beach sand. They had the potential to be converted to electricity. This paper explained the study of the hydrodynamic aspects of turbines that convert hydrokinetic and potential coastal wave energy. The vertical axis darrieus turbine was modified to catch both energies. It could convert energies from hydrokinetics and the potential of waves simultaneously, whereas a vertical axis turbine with 6 horizontal blades and 3 vertical blades in a shaft. Testing was done at the testing Tank, Hydrodynamic Technology Research Center, National Research and Innovation Agency. The hydrodynamic tests were with 3 turbine variations, wave variations, and current velocity. The test results, vertical axis turbines with horizontal blades could receive wave energy, due to the orbital motion of water particles and vertical blades were very effective in receiving current energy so that turbines with 2 types of vertical and horizontal blades could convert wave and current energy.
Performance Evaluation Of Permanent Magnet Synchronous Generator (PMSG) On Tidal Power Generation Optimization
Authors: Handoko C R , Mukhtasor  , Koenhardono E S 
Published: June 2023

Abstract
In a tidal current energy generation system, optimization of power generation can be done through turbine design, system design, and control of mechanical transmission from the turbine to the generator, as well as from the aspect of electronic generator output control. This research aims to analyze the performance of the PMSG generator from a prototype of the tidal current energy power plant. Turbine rotation is simulated using an ac motor equipped with an ac drive that supports separate speed and torque control. The hydraulic transmission system consists of a pump and a hydraulic motor that transfers the rotation of the turbine to the generator, where the power output is observed with variations in turbine speed and torque. The results indicate that the transmission system has worked well in transmitting the turbine’s mechanical power and increasing the rotational speed. The decrease in speed with increasing load and low average efficiency (less than 20%) occurs, mainly due to the characteristics of the generator being tested. The generator has a large rated torque requirement of 32 Nm, which is much higher than the main drive capacity of the turbine simulator. The design of a tidal energy conversion system, in which the tidal current speed fluctuates, requires careful selection of the generator, not only from the aspect of power capacity and rated rotational speed, but also from the initial torque value and required rated torque.
Study of Diameter-to-Draft Ratio of Pitch Point Absorber as Wave Energy Converter in Indonesia Waters Based on Boundary Element Method
Authors: Aulia A , Athallah A G , Albasyir M A , Selvia S P , Darisman H A , Satrio D 
Published: June 2023

Abstract
Recently, harnessing the energy from low wave energy density areas is concerned to deal with renewable energy targets. The previous study proposed a pitch point absorber with a submerged sectional equivalent area as the design parameter. However, that parameter did not suggest the best sectional area and did not directly correlate with the theory of structure hydrodynamic. Thus, this research proposes the diameter-to-draft ratio as a design parameter for the pitch point absorber. The study was conducted numerically using Boundary Element Method software to investigate diffraction characteristics of the device and analyze structure response in irregular waves. The model was modified with five different diameters and ratios. JONSWAP Spectrum was used to generate wave elevation with a 2-m significant wave height and 10-second peak period. The time domain simulation was set at 10.800 seconds. The result of this study showed that the highest responses occurred when the diameter-to-draft ratio was 5 because it has the closest structure natural frequency to assumed wave frequency, which makes it easier to resonate. In all diameters, the higher ratio affects the range of the structure natural frequency getting farther from the assumed wave, so the responses become smaller.
Oceanographic survey on current due to breaking wave for energy generations: a case study of Pacitan bay, East Java, Indonesia
Authors: Lestari S , Mukhtasor  , Satrio D , Rahmawati S 
Published: June 2023

Abstract
The southern sea of Indonesia faces the open ocean i.e., the Indian Ocean. This provides an initial hypothesis that the location has a ti potential for wave energy throughout the year. The current due to the breaking wave is estimated to have a high velocity. This study focuses on analyzing the velocity of current oceanographic survey due to breaking waves with a case study in Pacitan bay, East Java, Indonesia. The oceanographic survey method uses ADCP and a Current Meter to capture wave and current data sampling with the purpose of the research was for the electrical energy generation near the coast. ADCP is used to record the occurrence of waves and ocean currents before the wave break. The Current Meter is used to record current occurrences after the wave breaks. The instantaneous absolute current velocity, ca, and return current velocity, U, reach a value of 2-3 m/s.
Experimental and Numerical Studies on Motion Response of Side-by-Side Two Floating Vessels in Waves
Authors: Bafadhal H M , Prastianto R W , Murdjito  , Rosyid D M , Mulyadi Y , Ardhiansyah F 
Published: June 2023

Abstract
In the world of oil and gas, there will definitely be a structure for either the production process, exploration and so on. The structure consists of three types, namely the fixed structure, the floating structure and the moored structure. Floating structures can be the best option in terms of cost and time. Things that can interfere with floating structure when operating are environmental loads. One example of its operation is offloading, it can be offloading side by side or tandem configurations. The main focus of this study is the motion response both when single body and side by side configuration. The result of experimental studies obtained the maximum RAO (Response Amplitude Operator) for heave, surge, and pitch motion modes occurred when the model was configured side by side with a distance of 0.5 from the width. For numerical studies, the maximum RAO of heave motion when single body is 0.69 cm/cm, the maximum RAO of surge motion occurs when side by side configuration with a gap of 10 cm which is 0.71 cm/cm, and the maximum RAO of pitch motion occurs when the model is configured side by side with a gap of 10 cm which is 1.54 rad/rad.
Exploring the Impact of Covid 19 on the Maritime Transport Sector
Authors: Deeb Nowar , Leonardo Adam 
Published: June 2023

Abstract
In the maritime industry, The unanticipated COVID-19 viral epidemic is an unforeseeable circumstance, and other nations implemented enormous containment measures to stop the Coronavirus epidemic from spreading around the world. Thus, directly affecting the maritime shipping sector. This paper will discuss the current problems facing the shipping industry, taking into account the congestion problems, delays, and uncertainty timeframes, using the Los Angeles port as a case study. These problems and more were addressed directly by increasing the operating hours, workload, and available staff, and indirectly by looking for alternatives for shipping goods, and creating more cargo space, furthermore, this study will use Monte Carlo simulation to predict the effectiveness of these solutions on the congestion at the port.
Effects of adding sideboard and longitudinal bulkhead construction on ship stability of open-top cargo ship
Authors: Rosyada Amron , Endro W R Dimas , Arif Kurniawan M 
Published: June 2023

Abstract
The cargo cover removal on cargo ship will surely affect the technical condition of ship accomplishment that is regulated by rule. In this study, the author would like to evaluate the down-flooding point and free surface effect on open-top cargo ship to the stability acceptance criteria using IMO and DNV test procedures. The simulation result shows that the ship stability value is not in the range of the value required with IMO A.749(18) stability criteria. The failures are caused by lower down-flooding point and free surface effect. The Construction modifications effect by adding sideboard and longitudinal bulkhead is believed can increase the stability value. The simulation result using modified construction shows that the stability value is getting better. Using IMO MSC.Circular608 test procedure, the green-water is still allowed to enter cargo room of modified ship, 633,56 m3 at 25% load, 428,87 m3 at 50% load, and 194.94 m3 at 75% load. It is better than the previous ship that the green-water is not allowed at all. Using DNV test procedure, all of the modified ship stability values are accepted by IMO A.749(18). The value of area 30-40° is 21.06~21.00 m.deg and the value of maximum GZ angle is 28.2°.
Using genetic algorithm for fleet assignment of small-scale LNG supply chain
Authors: Hadi Firmanto , Supomo Heri , Achmadi Tri 
Published: June 2023

Abstract
This paper presents the development of a model of how to assign LNG carriers from a single LNG source to a number of scattered small-scale power plants in a milk-run operation strategy. Typically, researchers assume that ports/terminals to be visited are as given parameters. In this paper, the specifications of ports/terminals (infrastructures) are considered in the model as a consequence of the selected LNG carriers. The objective is to determine the optimum size and number of LNG carriers for a particular route by minimizing the unit logistics costs which include shipping costs and required infrastructures (ports and facilities) costs. The proposed approach of this paper is a metaheuristic by using genetic algorithm. The computational results shows that the optimal solution can be achieved in a relatively short period of time and the optimum cuve satisfies the law of deminishing returns. Finally, some encouraging computational results and suggestions for further study are presented.
Analysis of hull performance on fast patrol boat with an extended study of survivability under damaged conditions
Authors: Pratama A S , Prabowo A R , Muhayat N , Putranto T , Tuswan T 
Published: June 2023

Abstract
The prevalence of maritime accidents that occur due to ship leakage causes a significant risk to the safety of passengers and crew. Therefore, it is important to estimate stability during critical conditions, including characterizing the hull performance in sailing conditions. This research analyzes the effect of compartments and bulkheads on the ship’s stability when a leak occurs. The research method was carried out using the numerical approach to obtain resistance, stability, and large-angle stability results. The study also uses floodable length simulations to predict ship leakage and the distance between compartments. The variations were composed, including the location of the compartments and the distance between the partitions. Based on the obtained results, it can be seen that the addition of the compartment will affect the intensity of the ship to sink completely. Furthermore, the effect of leakage in each compartment will contribute to the stability state of the ship.
Effect of bilge keel variations on the designed fast patrol boats to hull resistance and stability behaviours
Authors: Rahmaji T , Prabowo A R , Muhayat N , Tuswan T , Putranto T 
Published: June 2023

Abstract
This study aims to analyse the effect of variations in the addition of bilge keel on the value of resistance, ship stability, and seakeeping performances. The research method is carried out by designing and analysing the hull design of the fast patrol boat type with variations in the addition of a bilge keel. Variations made on the bilge keel include length and width. The length variations are considered by applying 4 m, 5 m, and 6 m, while the variations in width include 0.3 m, 0.4 m, and 0.5 m. This study indicates that the nine variations of the bilge keels model with a combination of length and width do not show a significant difference in the resistance value on each ship. Then, for the stability criteria, the bilge keel model IX, with a length of 6 m and a width of 0.5 m, has the best stability value compared to other variations. Meanwhile, the addition of bilge keel in the seakeeping simulation did not show a significant difference. The parameters of this analysis consider the primary needs of fast patrol boats to support the development of shipping technology.
Formal Safety Assessment for determining sensitive area due to traffic of tourism vessels at Lombok Strait
Authors: Prastyasari F I , Dinariyana A A B , Nugroho T F , Sukmana A S 
Published: June 2023

Abstract
Lombok Strait has been determined as one of the Indonesia Archipelagic Sea Lane (IASL) passageways. It is also home to many tourism spots, such as Nusa Penida, that result in an increase in traffic density. Nusa Penida has been designated as a Marine Protected Area (MPA) since 2010. However, there is a need to define the sensitive area of Nusa Penida to protect it from the activities of vessels that can further harm the conserved area. Formal Safety Assessment (FSA) is a structured and systematic methodology that aims to improve safety in the maritime, including environmental aspects, using risk analysis and cost-benefit assessment. The result of this study is that ten hazards are categorized as possible hazards and then narrowed into five potential hazards—the one that will be analyzed is tourism activities. The frequency analysis of this study only considers tourism vessels namely Pleasure, Passenger, Fishing, and Sailing Vessels. The consequence analysis provided recommendations for a safe distance of vessels considering the hearing threshold of Sunfish (150 dB) which is 5000 m and coral reef (157 dB) is around 10 m. The proposed design of the sensitive area was based on the Nusa Penida MPA with changes in 2 coordinates considering ship activity as one additional aspect.
Design and experiment of high load-bearing acrylic connection node for the world's largest acrylic spherical vessel
Authors: Qian Xiaohui , Ma Xiaoyan , Heng Yuekun , He Wei , Qin Zhonghua , Tang Hongqiang , Xiao Jianxia , Zhang Gaofeng , Cheng Wei , Li Lei , Chen Tao , Liu Chang , Hou Shaojing , Pei Yatian , Yang Xiaoyu 
Published: June 2023

Abstract
Acrylic is a kind of polymer material and is gradually applied to load-bearing components. The working stress and ultimate bearing capacity of the acrylic structure are the main design indexes. Aiming at the world’s largest acrylic spherical vessel, the structural design, finite element analysis and full-size prototype tensile test of a new acrylic connection node were carried out in this paper. This acrylic node will bear 90 kN tension force for 20 years. According to the viscoelastic characteristics of the material and the working environment, the stress of acrylic should be controlled below 3.5 MPa for long term used. At the time, the ultimate bearing capacity should be greater than 6 times the working load. According to the stress-strain curve of acrylic, its tensile strength is about 75 MPa. There is no obvious plastic deformation after fracture, showing the material characteristics of brittle fracture. According to the failure analysis of previous acrylic node structures and the characteristics of acrylic, the new acrylic node structure is proposed in this paper. Its performance is improved by reducing the cutting amount of acrylic nodes, optimizing the structure of embedded part and avoiding sharp corners. A 1/4 symmetrical acrylic node model is established FEA software, and the nonlinear problems such as material nonlinearity and friction contact are solved by finite element method. The FEA results show that the maximum principal stress of the node is about 2.92 MPa. The relative error between the FEA results and the experimental results is 7.24%, indicating that the FEA results are credible. The ultimate tensile load of the node can reach 1000 kN, which is about 11 times the working load. The failure of the node occurs at a sharp corner of the groove, instead of the maximum stress point. Therefore, stress concentration caused by sharp corners should be avoided in the design of acrylic structure.
Microwave chemical durability of an iron-rich glass-ceramic dedicated for high-level radioactive waste
Authors: Moudir D , Souag R , Kamel N , Aouchiche F , Mouheb Y , Kamariz Soumia 
Published: June 2023

Abstract
This study investigates the effect of crystallization time (tc) in the structure of an iron-rich glass-ceramic (GC) dedicated for high-level radioactive waste (HLW), ceramized by nucleation–crystallization treatment at 790 °C for 2 h and 950 °C, for different periods ranging from 3 to 12 h. Density, XRD, SEM, FTIR, and Microwave chemical durability results are shown. Considering all the materials, Archimedes’ density is between 2.607 and 2.634 g cm−3. Both XRD and SEM analyses revealed the development of two main crystalline phases, spodumene (LiAlSi2O6) and (Zr, Ln) molybdate La2Zr3(MoO4)9, during the heat treatment. These phases regularly grow by the increase of crystallization time. They are known as radionuclides’ sequestration minerals. FTIR analysis confirms the complex GCs chemical composition. The microwave chemical durability test performed on GCs crystallized at tc = 9 h was conducted to evaluate their chemical stability. The leachates of the elements: Al, Fe, Mg, Li, Mo, Na, Si, and Zr were analyzed by ICP-OES. RLi values of Al, Mg, Mo, and Zr elements representing the radioactive waste (RW), vary between 2.3218 × 10−8 and 2.9204 × 10−8 kg m−2d. For Fe and Li, were slightly lower. However, RLSi was highest reaching 1.7457 × 10−6 kg m−2d−1. The elementary percentages extracted during the dissolution test for all elements are less than 0.5%, which makes our material chemically stable. Its resistance to such an aggressive dissolution test makes it a good candidate for the confinement of some RW elements.
Quasi-Self-Dual Codes over a Non-Unital Ring of Order 4
Authors: Dougherty Steven , Şahinkaya Serap 
Published: June 2023

We relate quasi-self-dual codes over a non-unital ring to additive self-dual codes over the additive group of the ring. We show that the Hamming weight enumerator of a quasi-self-dual code over this non-unital ring must belong to the same ring of invariants that self-dual codes over the Frobenius rings with unities belong. Additionally, the Hamming weight enumerator of a Type IV code over

E
E

must reside in the same ring of invariants as a Type IV code over the field of order

4
4

.
Technology-guided assessment of vocalisations and their diagnostic value as pain indicators for people living with dementia
Authors: Hoti Kreshnik , Atee Mustafa , Chivers Paola , Vahia Ipsit , Hughes Jeffrey 
Published: June 2023

Abstract

Background
during pain assessment in persons unable to self-report, such as people living with dementia, vocalisations are commonly used as pain indicators. However, there is a lack of evidence from clinical practice regarding their diagnostic value and relationship with pain. We aimed to explore vocalisations and pain in people with dementia undergoing pain assessments in clinical practice settings.

Methods
a total of 22,194 pain assessments were reviewed in people with dementia (n = 3,144) from 34 different Australian aged care homes and two dementia specific programs. Pain assessments were conducted by 389 purposely trained health care professionals and cares using PainChek pain assessment tool. Vocalised expressions were determined based on nine vocalisation features included in the tool. Linear mixed models were used to examine the relationship of pain scores with vocalisation features. Using a single pain assessment for each of the 3,144 people with dementia, additional data analysis was conducted via Receiver Operator Characteristic (ROC) analysis and Principal Component Analysis.

Results
vocalisation scores increased with increasing pain intensity. High pain scores were more likely with the presence of sighing and screaming (8 times). The presence of vocalisation features varied depending on the intensity of pain. The ROC optimal criterion for the voice domain yielded a cut-off score of ≥2.0 with a Youden index of 0.637. The corresponding sensitivity and specificity were 79.7% [confidence interval (CI): 76.8–82.4%] and 84.0% (CI: 82.5–85.5%), respectively.

Conclusion
we describe vocalisation features during presence of different levels of pain in people with dementia unable to self-report, therefore providing evidence in regard to their diagnostic value in clinical practice.