bluuebunny/crossref_metadata_2025 huggingface dataset:
AFRIMETS key comparison (AFRIMETS.M.M-K7) of five stainless steel mass standards: 5 kg, 100 g, 10 g, 5 g and 500 mg
Authors: Emira Sayed , Sayed B M , Wuethrich Christian , Souiyam Samira , Mutale Daniel , Mautjana Thomas , David Tonui
Published: September 2022

Main text

This key comparison is based on a decision of TCM of AFRIMETS on July 2015 in South Africa. TCM agreed that NIS-Egypt will pilot this comparison by providing the technical support and contributing to the link to the CCM comparison. The comparison consisted of one set of five stainless steel mass standards with nominal values: 5 kg, 100 g, 10 g, 5 g and 500 mg. These masses are owned by the LPEE-LNM and chosen to be the transfer mass standards. The pilot laboratory (NIS) measured the volume and the magnetic properties of the standards before the circulation and had reported these values to the participants. The pilot laboratory has also verified the stability of all travelling standards for one year.

Six laboratories measured the set of travelling standards between September 2018 and December 2019.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Nonresonant Multiphoton Ionization of Stark Decelerated Molecules by Femtosecond Laser Pulses
Authors: Meng Congsen , Lü Zhihui , Wang Xiaowei , Zhang Dongwen , Zhao Zengxiu , Yuan Jianmin
Published: September 2022

Nonresonant multiphoton ionization by femtosecond laser pulses can be applied to any molecule virtually, thereby greatly enhancing the scope of Stark decelerated molecules. For comparison, we detect decelerated and trapped ammonia molecules using two different schemes: (i) nonresonant multiphoton ionization using intense femtosecond (fs) pulses in the near infrared, and (ii) resonance-enhanced multiphoton ionization using nanosecond (ns) pulses from a tunable UV laser. The observed number of ions per shot for both schemes is similar. The fs laser detection scheme suffers from an increased background, which can be effectively eliminated by subsequent mass and velocity selection. To determine the detection volume of the ns laser detection scheme, we present measurements in which the decelerated ammonia molecules are bunched to a packet with a longitudinal spread well below ∼100 μm. It is concluded that the detection volume for the ns laser detection scheme is 1.5–2 times larger than that of the fs laser detection scheme.
Optimization of PEC and photocathodic protection performance of TiO2/CuInS2 heterojunction photoanodes
Authors: Cheng Hongmei , Wang Xiaotian , Bai Zhiming , Zhu Chuang , Zhang Zhibo , Zhang Qiang , Wang Qi , Dong Hailiang , Xu Bingshe
Published: September 2022

The establishment of heterojunction is a powerful strategy to enhance the photoresponse performance of photoanode. Here, TiO2/CuInS2 (T/CIS) composites were prepared via a two-step hydrothermal method, and their morphologies were controlled by adjusting the reaction time. The absorption spectra show that CuInS2 can significantly improve the absorption of visible light. The T/CIS2 (2 h reaction time) photoanode exhibited the most outstanding photoelectrochemical (PEC) performance, with a photocurrent density of 168% that of the pure TiO2 photoanode. Under simulated sunlight, this photoanode can supply a protective photocurrent of 0.49 mA cm−2 and a protective voltage of 0.36 V to stainless steel (304ss), which are about 4 and 2 times those of the TiO2 sample. The enhancement in the photocathodic protection performance is attributed to enlarged visible light absorbance and higher charge separation rate. This study demonstrates that the TiO2/CuInS2 photoanode is a promising candidate for application in photoinduced cathodic protection of metallic materials.
Unusual charge states and lattice sites of Fe in Al
x
Ga1−x
N:Mn
Authors: Masenda Hilary , Gunnlaugsson Haraldur Páll , Adhikari Rajdeep , Bharuth-Ram Krish , Naidoo Deena , Tarazaga Martín-Luengo Aitana , Unzueta Iraultza , Mantovan Roberto , Mølholt Torben Esmann , Johnston Karl , Schell Juliana , Mokhles Gerami Adeleh , Krastev Petko , Qi Bingcui , Ólafsson Sveinn , Gíslason Haflidi Pétur , Ernst Arthur , Bonanni Alberta
Published: September 2022

Charge states and lattice sites of Fe ions in virgin and Mn-doped Al
x
Ga1−x
N samples were investigated using 57Fe emission Mössbauer spectroscopy following radioactive 57Mn+ ion implantation at ISOLDE, CERN. In the undoped Al
x
Ga1−x
N, Fe2+ on Al/Ga sites associated with nitrogen vacancies and Fe3+ on substitutional Al/Ga sites are identified. With Mn doping, the contribution of Fe3+ is considerably reduced and replaced instead by a corresponding emergence of a single-line-like component consistent with Fe4+ on Al/Ga sites. Density functional theory calculations confirm the Fe4+ charge state as stabilised by the presence of substitutional Mn2+ in its vicinity. The completely filled spin up orbitals in Mn2+ (3d5) are expected to enhance magnetic exchange interactions. The population of the Fe4+ state is less pronounced at high Al concentration in Al
x
Ga1−x
N:Mn, a behaviour attributable to hybridisation effects of 3d states to the semiconductor bands which weakens with increasing (decreasing) Al (Ga) content. Our results demonstrate that co-doping promotes the co-existence of unusual charge states of Fe4+ and Mn2+, whereas their trivalent charge states prevail with either transition metal incorporated independently in III-nitrides. Co-doping thus opens up a new avenue for tailoring novel magnetic properties in doped semiconductors.
Abnormal magnetic behavior of prussian blue analogs modified with multi-walled carbon nanotubes
Authors: Mo Jia-Jun , Xia Pu-Yue , Shen Ji-Yu , Chen Hai-Wen , Lu Ze-Yi , Xu Shi-Yu , Zhang Qing-Hang , Xia Yan-Fang , Liu Min
Published: September 2022

This work examines the origin of the abnormal magnetism exhibited by CuMnFe–PBAs modified with multi-walled carbon nanotubes (MWCNTs). The system of CuMnFe–PBAs@MWCNTs coexists with both large and small clusters. CuMnFe–PBAs clusters have an average particle size of 28 nm, and some of the smaller particles are adsorbed on the surface of MWCNTs. Surprisingly, the magnitude of magnetization increases linearly with decreasing temperature. When above the Curie temperature, the magnitude of magnetization is significantly greater than that of PBAs without being modified. This phenomenon can be attributed to magnetostatic interactions between ultra-fine magnetic nanoparticles adsorbed on the surface of MWCNTs. Using the Monte Carlo method, we simulated the magnetostatic interaction of cylindrical adsorbed particles, and the simulation results are almost identical to those observed experimentally. The results indicate that 0.089 CuMnFe–PBAs clusters per 1 nm2 can be adsorbed onto the surface area of MWCNTs. We demonstrate that MWCNTs adsorbing magnetic particles exhibit magnetic behavior, and suggest a method for producing ultrafine materials. It also introduces a new method of calculating the adsorption efficiency of carbon nanotubes, offering theoretical guidance for future research on nanomaterials with enhanced adsorption efficiency.
Insights into the nature of X(3872) through B meson decays*
Authors: Zhang Zhi-Qing , Guan Zhi-Lin , Zhao Yan-Chao , Zhang Zi-Yu , Sun Zhi-Jie , Wang Na , Ren Xiao-Dong
Published: September 2022

We study the

decays in the perturbative QCD (PQCD) approach, involving the puzzling resonance

, where P represents a light pseudoscalar meson (K or π). Assuming

to be a

charmonium state, we obtain the following results. (a) The branching ratios of the

and

decays are consistent with the results predicted by the covariant light-front approach within errors; however, they are larger than those given by the generalized factorization approach. (b) The branching ratio of the

decay is predicted as

, which is smaller than the previous PQCD calculation result but still slightly larger than the upper limits set by Belle and BaBar. Hence, we suggest that the

decays should be precisely measured by the LHCb and Belle II experiments to help probe the inner structure of

. (c) Compared with the

decays, the

decays have significantly smaller branching ratios, which drop to values as low as

. (d) The direct CP violations of these considered decays are small (

) because the penguin contributions are loop suppressed compared to the tree contributions. The mixing-induced CP violation of the

decay is highly consistent with the current world average value

%. Experimentally testing the results for the branching ratios and CP violations, including the implicit

and isospin symmetries of these decays, helps probe the nature of

.
Calomplification — the power of generative calorimeter models
Authors: Bieringer S. , Butter A. , Diefenbacher S. , Eren E. , Gaede F. , Hundhausen D. , Kasieczka G. , Nachman B. , Plehn T. , Trabs M.
Published: September 2022

Motivated by the high computational costs of classical simulations, machine-learned generative models can be extremely useful in particle physics and elsewhere. They become especially attractive when surrogate models can efficiently learn the underlying distribution, such that a generated sample outperforms a training sample of limited size. This kind of GANplification has been observed for simple Gaussian models. We show the same effect for a physics simulation, specifically photon showers in an
electromagnetic calorimeter.
Performance of BeBe, a proposed dedicated beam-beam monitoring detector for the MPD-NICA experiment at JINR
Authors: Ayala-Torres Marco Alberto , Espinoza Beltrán Lucina Gabriela , Fontaine Sanchez Marcos Aurelio , Hernández-Cruz Luis A. , Montaño Luis Manuel , Maldonado Luna Braian Adair , Moreno-Barbosa Eduardo , Rebolledo-Herrera Lucio F. , Rodríguez-Cahuantzi Mario , Reyna-Ortiz Valeria Z. , Tejeda-Muñoz Guillermo , Zepeda Fernández C.H.
Published: September 2022

The Multipurpose Detector (MPD) is an experimental array, currently under construction,
designed to study the nuclear matter created during the collisions that will be provided by the
Nuclotron-based Ion Collider fAcility (NICA) at JINR. The MPD-NICA experiment consists of a
typical array of particle detectors as those used to study heavy-ion collisions at LHC and
RHIC. To increase the trigger capabilities of MPD for stage 2 of NICA operation, a detector
constituted by two arrays of 80 plastic scintillator cells each located symmetrically at opposite
sides of the interaction point of MPD is proposed (BeBe). Based on Monte Carlo simulations, a
discussion of the potential physics performance of BeBe detector is given for triggering tasks and
for the resolution in the determination of the event plane reaction and the centrality of the
collisions at NICA. Also, laboratory measurements to estimate the time resolution of individual
BeBe cells prototypes are presented. It is shown that a time resolution between 0.47 and 1.39 ns
can be reached depending on the number of photosensors employed to collect the scintillation
photons. The BeBe detector will be complementary to FFD and FHCAL forward detectors.
Measurement and sampling techniques verification for an online gaseous tritium monitoring method
Authors: Chen Qianyuan , Liu Changjun , Zhao Guangyi , Chen Chongyang , Zhuo Weihai
Published: September 2022

During the development and envisaging of an online monitor method, a selection of measurement techniques, counting processes, instrument and sampling methods were performed. Firstly, Liquid scintillation counting was found to be the suitable technique, mass to volume ratio between pretreated water and liquid scintillation cocktail, the MDCs for 3 different liquid scintillation counter (LSCs) were tested individually. The results show that the minimum available MDC of Aloka LB7 is 0.39 Bq L-1 at the condition of 50 g pretreated water, being the one chosen to be the measurement LSC. Secondly, vapor condensation method, which could collect at least 201 g of water each day, was chosen among 3 tested sampling methods. Finally, automatic machinery measures were implemented to integrate the online monitoring method. A stable running status was proved by 15 days of duration test, which indicated that the chosen measurement and sampling technique are suitable for online monitoring.
Snow-influenced floods are more strongly connected in space than purely rainfall-driven floods
Authors: Brunner Manuela I , Fischer Svenja
Published: September 2022

Widespread floods that affect several catchments are associated with large damages and costs. To improve flood protection, a better understanding of the driving processes of such events is needed. Here, we assess how spatial flood connectedness varies with the flood generation process using a flood event classification scheme that distinguishes between rainfall-driven and snowmelt-influenced flood types. Our results show that the dominant flood generation processes in Europe vary by region, season, and event severity. Specifically, we show that severe floods are more often associated with snow-related processes than moderate events. In addition, we find that snow-influenced events show stronger spatial connections than rainfall-driven events. The spatial connectedness of rainfall-driven events depends on the rainfall duration, and the connectedness decreases with increasing duration. These findings have potential implications for flood risk in a warming climate, both locally and regionally. The projected decrease in the frequency of occurrence of snowmelt-influenced floods may translate into a decrease in the frequency of severe and widespread floods in catchments where snowmelt processes are important for flood generation.
Is crushed concrete carbonation significant enough to be considered as a carbon mitigation strategy?
Authors: Ruschi Mendes Saade Marcella , Yahia Ammar , Amor Ben
Published: September 2022

When addressing concrete carbonation as a carbon mitigation option, studies leave out the effect that a temporal difference between the CO2 emissions and uptake happening throughout concrete’s life cycle have on climate change. In this study, the role played by carbonation on concrete’s carbon mitigation potential is investigated through a dynamic life cycle assessment, to properly position CO2 uptake and release. The carbon balance in concrete structures built and demolished from 2018 to 2050 is modelled as a case study. The potential uptake due to crushed concrete carbonation is over 9% of the cumulative global warming effect of concrete manufacturing. It is comparable to the reduction potential of the most promising strategy, namely replacing clinker, totaling 12%. If stimulated in a wide scale, crushed concrete carbonation can push the industry towards meeting carbon mitigation targets faster. Future environmental impact assessments should rely on dynamic models to increasingly consider this phenomenon.
After the dark ages*
Authors: Fröhlich Jürg
Published: September 2022

After recalling some puzzles in cosmology and briefly reviewing the Friedmann–Lemaître cosmos a simple unified model of the ‘dark sector’ is described. This model involves a scalar field and a pseudo-scalar axion field that give rise to dark energy in the form of ‘quintessence’ and to ‘fuzzy’ dark matter, respectively. Predictions of the model concerning the late-time evolution of the Universe and possible implications for the problem of the observed matter–antimatter asymmetry in the Universe are sketched.
System Dynamics Modelling Scenarios for The Import Receiving Infrastructures Capacity Plan & Development in anticipating Future Deficits of Natural Gas Supply in Indonesia.
Authors: Purwosaputra A A , Artana K B , Dinariyana A A B
Published: September 2022

Indonesia is one amongst the biggest natural gas reserves country in south East Asia, with total reserve of about 142,71 TSCF in 2018. Indonesian demand for energy is also increasing over the time in line with its economic and population growth. The improved of global consciousness toward the sustainable environmental issues, has led in to the choice over an affordable source of energy with a less carbon footprint. On the other hand the natural gas supply and domestic production is depleting. At the current rate of consumption and assuming no new reserves discoveries, sooner or later Indonesia will have to face deficit in gas supply. This study, is first aimed to forecast the Indonesia supply and demand situation of natural gas in years to come, and then performing an analysis and assessment toward the availability and adequacy of the required infrastructures especially receiving terminals facilitating for gas import in anticipation of future deficit of gas supply in Indonesia. From which, it will be further analyzed, the geographical distribution of the demand and then potential short of supply in several regions and areas where the demand are most concentrated. Thus few basis System Dynamics scenarios of public policies were simulated for 30 years running simulation. System Dynamics model simulation has been well known as a powerful tool to represent a complex industrial problems such as national energy systems. The result is unveiled the fact that additional import receiving terminals and storage facility is required at certain areas where the deficits most likely exist, and most of them in fact are in Western Zone of Indonesian.
Dynamic Safety Modelling for Ship Management Performance
Authors: Nizar Adi Mas , Nakamura Masumi , Miwa Takashi , Uchida Makoto
Published: September 2022

Recent development and projection of ship operations as a sociotechnical system is getting more complex. In order to successfully emulate a high-reliability organization with a balance between operational efficiency and safety, the shipping companies have to grab a well understanding of the operating performance. However, because the teams are distributed spatially and temporally, a misalignment of shared situation awareness casually exists. We extended Rasmussen’s dynamic safety theory and adjusted it in the context of ship management performance. A modelling study using system dynamics was done to illuminate how the feedback loops construct the interaction between safety, efficiency, and workload. The simulation result shows that the operations behave following the safety and efficiency pressures created by existing goals and boundaries. The model is also able to capture these trade-offs in different variety of operation scenarios. Application such modelling may provide the managers with a better understanding and valuable insight to implement the strategies to sustain safe operations.
Experimental study of a ship with the self-righting moment in extreme condition
Authors: Trimulyono A , Zakki A F , Fuadi M A
Published: September 2022

Patrol vessel is an essential part of offshore security archipelago countries such as Indonesia. The main feature of patrol vessel is operating in rough waves during operation. Ship stability is one of the challenging aspects of patrol vessel because, in extreme conditions, the ship can capsize due to losing a self-righting moment. The present paper carried out a study of a patrol vessel with a self-righting moment in extreme conditions. The condition is a ship with rolling up to above 180°. Thus, the ship can capsize because of losses of the self-righting moment in rough condition. An experimental study is carried out to model a ship with a rolling angle above 180°. The principal dimension of ships Lpp, B, H, T, are 13.0 m, 4.2 m, 2.19 m and 1.15 m, respectively. The study was carried out with a physical model of ship 1:27.4. The model is made using 3D printing to maintain the hull integrity. In the present paper, only the full load condition was tested in the experiment condition. It was showed the ship design was proven to have a self-righting moment in the rolling angle above 180°.
Analysis The Effect of Outrigger (Cadik) Variations on Motion Response of Fishing Boat Using CFD Method
Authors: Darmawan Akbar Bagus , Eka Darma Yeddid Yonatan , Rulianto Jangka
Published: September 2022

Jukung is a type of traditional fishing boat used as transportation for fishing activities in Muncar, Banyuwangi, which has a wave as high as 2 m with a period of 4.6 s which is classified as 2nd sea state. One of the boats used has a length of 7.2 m, width 0.75 m, and height of 0.8 m. The characteristics of the hull which with an L/B ratio of 9.6 require outriggers to help balance while sailing. The outrigger itself is a cylindrical component that is placed at a certain distance on both sides of the boat. Since ancient times, the construction of outrigger boats has been carried out by local artisans by relying on experience. This is certainly very risky because it is not known for certain whether the construction, in this case, the outrigger can keep the boat stable. For this reason, we researched the boat’s motion using the CFD method to provide a reference for the construction of the outrigger design. Using one of the existing boats with LOA 7.2 m, B 0.671 m, and H 0.8 m, and Vs 4.385 kt as a simulation model, we varied the outrigger-centerline distance by 2.5 m and 2.8 m; diameters of 90 mm, 120 mm, and 150 mm; which tested under conditions of full load and light load with the wave directions of headsea (180°), headquarter (135°), and beamsea (90°), resulting in Response Amplitude Operator (RAO) as follows. The model with an outrigger-CL distance of 2.8 m and diameter of 150 mm has the lowest heaving value of 0.02 m/m at a frequency of 4.1 rad/s from the headsea direction, 0.44 m/m at a frequency of 3.7 rad/s from the headquarter direction, and 0.4 m/m at a frequency of 6.2 rad/s from the beamsea direction. This model also has the lowest value in pitching and rolling responses from all directions with each value of 0.4 rad/m to 0.15 rad/m in pitching and relatively 0 rad/m in rolling responses.
Development of the Elements of Tugboat Handling for Berthing and Unberthing of Container Ships
Authors: Asmara I P S , Kristianto D , Mustaghfirin M A , Praharsi Y , Adianto  , Arfianto A Z , Firmansyah C A
Published: September 2022

This paper provides a study on the procedure of tugboat handling for berthing and unberthing of container ships in the Port of Surabaya Container Terminal. The elements of the tugboat assistance consisted of time series of the percentage of tugboats’ power, the direction of the tug’s force, and the duration. This study developed a manoeuvring simulation program using the mathematical manoeuvring group (MMG) model to determine the handling elements to achieve the intended trajectory properly. The model considered the surging force, swaying force, and yawing moment of tugs, as well as the disturbances of current, wind, and wave. The planning trajectory is determined based on berthing and unberthing passages derived from the automatic identification system (AIS) data. The elements resulting in the berthing speed and berthing angle complied with the Permanent International Association of Navigation Congresses (PIANC).
The study of the Modification of the Ro-Ro Ferry’s Angle of the Entrance Using Statistical Methods and Ship Model Resistance Tests
Authors: Cahyadi Sugeng JM , Semin  , Erwandi
Published: September 2022

Aspects of speed and its correlation to ship resistance greatly affect the performance of ferry ro-ro ships. The fixing of the ship’s resistance is very significant when related to the ship’s economic costs. BTH-BRIN has carried out resistance tests and calculations using the Holtrop statistical method where the resistance result is considered too large. To reduce the resistance, modifications are made, one of which is by changing the angle of the entrance of the ship bow. Again, the Holtrop statistical calculations are then employed to determine the effective angle of the entrance after the ship is modified. Reducing the angle of the entrance of water at the ship’s bow is expected to reduce the resistance in terms of the bow wave. It also needs paying attention to the amount of ship payload that has been planned. This paper describes the process of resistance reduction due to the change of the angle of the entrance of the ferry ro-ro ship. Firstly the resistance of the original ship is predicted using the statistical method and a scaled ship model is made and tested in BTH towing tank. Second, the angle of the entrance of the ferry ro-ro ship is modified. Finally, the modified one is predicted statistically based on the Holtrop method. The results of the statistical analysis of the modified angle of entrance showed that the resistance is smaller than the original one.
Study on the Application of Microcontroller-Based GPS Sensors on Floater Gliders to Reach the Specified Destination
Authors: Purnomo Nanang J H , Masroeri A.A. , Nugroho Wibowo H , Sahlan
Published: September 2022

The purpose of the study is to determine the performance of the control system of the floater glider to a predetermined location. The method used was a combination between software simulation and an experimental free-running test. The Floater control system is equipped with GPS as input and output sensors to determine coordinates or waypoints. The microcontroller mounted was Pixhawk 2.4.8 based on ARM cortex M4 – 32 bits. The floater was driven by two Brushless DC motors and servo motors to drive the Z-Peller steering to the desired trajectory. The floater system applies the default application software from Pixhawk, namely mission planner to plan and also monitor the actual trajectory. To have a proper procedure for testing the designed control system, the three stages of the test were conducted, firstly numerical tuning test using step function on MATLAB simulation, then trajectory simulation test of waypoint using mission planner, and finally the field test in the ILH pond. From the three stages of the test, it was found that the selection of PID gain values Kp = 0.2, Ki = 0.3, and Kd = 0.02, indicating the performance of the floater glider control system to the planned location has a good fit between the trajectory simulation results and the waypoint testing in the pond. These results can be used as a reference in conducting further research so that the navigation accuracy of the control system will be improved.
Meshing generation strategy for prediction of ship resistance using CFD approach
Authors: Yulianti Serliana , Samuel S , Nainggolan T S , Iqbal Muhammad
Published: September 2022

CFD is a numerical approach used to solve fluid problems. In the CFD simulation process, the meshing stage is crucial to produce high accuracy. Meshing is a process where the geometric space of an object is broken down into many nodes to translate the physical components that occur while representing the object’s physical shape. The research objective was to analyze the characteristics of the mesh technique in the Finite Volume Method (FVM) using the RANS (Reynolds - Averaged Navier - Stokes) equation. The numerical simulation approach used three mesh techniques, namely overset mesh, morphing mesh, and moving mesh. The k-ε turbulent model and VOF (Volume of Fluid) were used to model the water and air phases. The mesh technique approach in CFD simulation showed a pattern under experimental testing. This research showed the difference in value to the experimental results, namely by using the moving mesh method, the difference in resistance difference was 8% at high-speed conditions, the difference in trim value at overset mesh was 11%, and the difference in heave value with the moving mesh method was 14% at low speed. The conclusion reported that overset mesh had better than other mesh methods.
The Performance of KH and KG Flexible Riser with Distributed Buoyancy Modules Configuration
Authors: Priyanto Muhammad Pratikto , Putra Danasesha Paradinda , Iskandar Iis
Published: September 2022

As a relatively new technology in the riser structure, Distributed Buoyancy Modules (DBM) are seldom to use on flexible risers in Indonesia Oil and Gas Fields which are dominated by brown fields. DBM have several advantages compared with conventional subsea structures such as Mid-Water Arches (MWA) in installation phase. DBM provides lower budget spending due to the shorter period and easier method in installation phase. The paper presents engineering design of DBM operation and installation in Kakap Field, Natuna Sea, Indonesia to replace the existing KH and KG Risers. Several cases was evaluated in this paper to perform the behaviour of risers using DBM. Based on the static analysis, the maximum effective tension for KH Riser and KG Riser are 100.7 KN and 83.4 KN respectively during their operation with allowable value of less than 1530 KN. Meanwhile, the minimum bending radius for the risers when they are being operated are above the allowable value of 3.926 m which are 6.6 m and 6.7 m for KH and KG Riser in turn. The analysis indicates the both of risers are safe to operate during their life period.
Economic feasibility study due to implementation of dual fuel engine of mini-LNG carrier in LNG distribution to power plants in Bali and Lombok
Authors: Pratiwi Emmy , Made Ariana I , Handani Dhimas Widhi , Dinariyana A A B , Artana Ketut Buda , Abdillah Hayy Nur
Published: September 2022

The fact that the maritime transport contributes 2.8% of global greenhouse gas (GHG) emissions challenges the ship to reduce the CO2 emissions. International Maritime Organization (IMO) requires limiting the sulphur to 0.5% m/m in the fuel oil used on board ships operating outside designated emission control. One of strategies to comply the IMO regulations is by using the alternative fuels which may contain low or zero sulphur for ship main engine and that is liquefied natural gas (LNG). Instead of retrofitting the diesel engine which economically requires higher cost, engine conversion to dual fuel diesel engine is preferable in this study. Before the conversion of dual fuel diesel engine is implemented, the feasibility study should be performed, both technically and economically. This study focused on the economic analysis due to conversion of dual fuel engine using LNG fuel. The study case in this research is the plan of dual fuel engine conversion of Landing Craft Tank (LCT) as mini-LNG carrier for distributing the LNG ISO tank to power plants in Bali and Lombok. The economic analysis in this study was carried out to adjust several components in Capital Expenditure (CAPEX) and Operational Expenditure (OPEX) that occurred due to dual fuel engine conversion. Finally, the result of this papers shows that the dual fuel engine conversion for mini-LNG carrier for gas distribution is economically feasible since it gives the smaller cost compared to diesel engine.
Study on Natural Gas/Diesel Dual-fuel Engine Energy Ratio: Effect of Natural Gas Injection Parameters
Authors: Felayati Frengki Mohamad , Dwisetiono  , Prasutiyon Hadi , Ariani Betty
Published: September 2022

Natural gas has been a promising demand for several years in Indonesia as a fuel for a diesel engine by converted into a natural gas/diesel dual-fuel engine. However, determining the energy ratio of the diesel and natural gas fuel is important due to the engine performance and emissions which affect the engine safety operation. This study presents the method to determine the natural gas and diesel fuel energy ratio on intake port natural gas injection mode through experiment. A direct injection diesel engine is converted to a natural gas/diesel dual-fuel engine by injecting natural gas into the intake port. The diesel injection parameters are unmodified for the experiment; besides the natural gas injection variations are studied to determine the energy ratio. Moreover, the engine is tested for low to high load conditions. However, natural gas injection duration, pressure, and injection timing variation affect the fuel energy ratio and indicated thermal efficiency (ITE). At low load, the optimum fuel energy ratio and ITE are achieved at a long injection duration (10 ms) and with advanced injection timing. Moreover, at high load, the optimum fuel energy ratio and ITE is achieved at high natural gas injection duration (12 ms), high injection pressure (3 bar), and advancing the injection timing.
The Application of Emergency Safety Device for The Improvement of Marine Operation of a Gas-Powered Ship
Authors: Santoso Agoes , Zaman Muhammad Badrus , Saihilmi Muhammad Irsyad
Published: September 2022

A new Emergency Safety Device (ESD) based on a PLC module that can start and stop a modified dual-fuel diesel engine in automatically has been created. When fitted to a modified dual fuel engine, the laboratory scaled PLC module has been tested and found to perform well in any programmable emergency circumstance. Because the modified engine’s compression ratio has been increased, the risk of hazards has increased as well. When any pre-defined dangers are recognized, the ESD logical code can automatically control the functioning of the fuel system to provide uninterrupted fuel delivery, but it can also halt the fuel supply, including gas and diesel fuel. Over-pressure, over-temperature, flow rate, rpm, and gas leakages are all potential hazards. To identify those potential hazards, then scoring method is used to model and simulate them quantitatively. The simulation data is used as input data for Arduino Source Code, which is used to process logical acts in the marine engine operation. Finally, the safety level is assessed using a safety standard approach such as the SHEL Method. The results of the works show that ESD eligible to control the operation of gas fuel system and it is considerable to be applied for gas-powered ship.
Analysis of a Lower Deck Rigging Configuration and Reusable Padeye Design based on Finite Element Model for Improving Stacking Operation Efficiency
Authors: Giri Kautsar Robbi Yahya , Prastianto Rudi Walujo , Rifqy Mohammad Jazil , Farhana Roficho Filzah
Published: September 2022

In the topside fabrication process, the decks will be fabricated first simultaneously and then they will be arranged sequentially to form the topside through a stacking operation. The integrity of the deck structure must be maintained during and after the stacking process. The integrity of the deck structure and rigging system is strongly influenced by the design of the rigging system. Meanwhile, the design of the rigging system is limited to the equipment available to the company. So, it is necessary to analyze a proper rigging configuration with the existing limitations. In this case study, the rigging design and stacking analysis of the lower deck structure were carried out. From the analysis results, the 4 crane rigging configuration is used, with the highest crane utilization occurring on the crane is 89%. In the rigging system, the smallest safety factor on the sling is 1.17, and the shackle is 1.12, while on the deck structure the maximum UC is 0.32 and the maximum deflection that occurs is 2.17 cm. The reusable padeye UC is 0.53 in the numerical method analysis with a maximum von misses stress is 191 MPa which was concentrated at the lower end of the stiffener plate.
Impact Assessment of Breaking Waves Criteria Subjected to Wave Energy Converter
Authors: Prastianto Rudi Walujo , Assidiq Fuad Mahfud , Mukhtasor
Published: September 2022

Breaking wave effect on Wave Energy Converter (WEC) represents an important issue of site selection analysis especially fringing reefs area. To learn a more acceptable sense of the influence of this effect, an introspection on the estimate of initial breaker points is proposed in the present study. The paper describes an investigation of the impact assessment of wave-breaking criteria subjected to WEC recently desired as a benchmark by the previous three wave-breaking methods. The numerical simulation is carried out by the Computational Fluid Dynamics (CFD) solver. The solver is based on the Finite Volume Method (FVM) to create the discretization of the governing equations. Large Eddy Simulation (LES) is solved in a global approach together with Volume of Fluid (VoF) for capturing free surface. Reported justifications are compared with the experimental data to validate the accuracy of the numerical approach and then applied to generate wave-breaker point location on a fringing reef in Numerical Wave Tank-based (NWT) of 16 scenarios. The results are discussed with respect to relative wave-breaker locations, relative wave-breaker height range, and wave breaking probability under various wave steepness, water depth, and slope fringing reef. It is given regarding the discrepancy between different methods and recommendations for important guidances are outlined.
Performance analysis of dual-stage vertical axis hydrokinetic turbine (VAHT) with azimuth variation at open canal hydrokinetic power plant
Authors: Hantoro R , Septyaningrum E , Nugroho G , Alam M F A , Fawwaz M D , Alfarisyi F D , Alfarizi M I , Prasetyo R A
Published: September 2022

For several decades, the use of hydropower generation using hydrokinetic turbines has grown rapidly, aiming to get energy alternatives and reduce the dependency on fossil energy. Despite it has low efficiency, the vertical axis hydrokinetic turbine (VAHT) has been used to utilize hydro energy and has a promising result. A previous study had stated that the utilization of cascaded blade enhances the performance of VAHT. However, this technology produces fluctuating torque and power during its rotation. Hence the dual-stage VAHT is proposed to overcome this issue to improve VAHT’s efficiency. This research analyzes the dual-stage VAHT’s performances by variating its inter-stage azimuth of 45°, 60°, 75°, and 90°. For each stage, there is six blades that attach at three arms. The computational fluid dynamics (CFD) simulation is employed as its capability to provide in-depth information regarding flow phenomenon, force, and torque. This simulation has proven that the dual-stage configuration has an impact on reducing torque fluctuation of VAHT and show that different of inter-stage azimuth angle brings to different torque fluctuation pattern. The average torque value produced by the new turbine with variations in shift between stages of 45°, 60°, 75° and 90° is 10,119.21 Nm, 10,656.13 Nm, 10,490.31 Nm, and 10,457.3 Nm, respectively.
Self propulsion Performance Analysis of Japanese Bulk Carrier with PBCF Based CFD Method
Authors: Nugraha Oloan Achdri Fauzi , Made Ariana I , Baidowi Ahmad
Published: September 2022

An energy-saving device (ESD) is used to obtain energy lost and convert additional energy to a propulsive coefficient. This research uses PBCF as an energy-saving device that is attached to an MP687 propeller and a Japanese bulk carrier a hull. Method for solving this research using the open water test and self propulsion method based on computational fluid dynamic (CFD). Added propulsive coefficient obtained from PBCF conventional can reach up to +1.52 %. PBCF with duct make smaller added for propulsive coefficient caused by duct splitting fluid flow from the propeller. PBCF with duct can increase propulsive coefficient up to +0.48 %. PBCF can eliminate a strong hub vortex at propeller MP687 and its ba e good choice for the increased propulsive coefficient of the ship
Risk Evaluation Concept of Engine Room Module Installation on Modular Construction Shipbuilding
Authors: Baroroh Intan , Made Ariana I , Dinariyana AAB
Published: September 2022

The implementation of the construction of modular construction ships is able to accelerate ship production by up to 50%. However, in practice, delays in the production process can still be found in the engine room module of the modular ship building process. Production delays occur due to inappropriate block dimension accuracy, damaged machine conditions, loading blocks that are not on schedule, many revisions to drawings, delays in equipment and basic ship materials. The production process includes a series of activities carried out including: Hull construction, Painting & Protection, Outfitting Manufacture, Machinery Outfitting, Accommodation Outfitting, Electric, Electrical Outfitting. This research aims to evaluate the performance of engine room module installations in shipyards that apply a modular construction system. At an early stage, the research was conducted by identifying factors and constraints that affect the performance of the engine room installation in shipbuilding which has the potential to cause delays. The conceptual and technical approach are carried out by analyzing the causal relationship of the identification of factors at the production stage. The results of this research is expected to anticipate earlier delays in the engine room module installation with the concept of evaluation using Bayesian Network integration and System Dynamics.
Lysozyme-assisted ultrasonic exfoliation of graphitic carbon nitride into highly stable nanosheets with enhanced bactericidal capacity
Authors: Chen Liang-Liang , Shi Wen-Pu , Zhang Tuo-Di , Zhou Ren-Bin , Jin Xiao-Qian , Zhou Ya-Qing , Lin Wen-Juan , Guo Wei-Hong , Yin Da-Chuan
Published: September 2022

Graphitic carbon nitride (g-C3N4) is a visible light-responsive photocatalytic material with important application prospects in many fields. However, the interaction between g-C3N4 monolayers makes it easy to aggregate and precipitate in aqueous solutions, and it is necessary to prepare stable g-C3N4 aqueous dispersions for their applications. Here we propose a facile, green, and low-cost method for the preparation of stable g-C3N4 dispersions by ultrasonicating g-C3N4 in lysozyme (LYZ) solution. The LYZ was adsorbed on the surface of g-C3N4 through non-covalent interactions such as electrostatic interaction, hydrogen bonding and π-cation interaction to prevent the aggregation of g-C3N4 nanolayers. The LYZ/g-C3N4 could quickly re-form a uniform aqueous dispersion solution after freeze-drying, and exhibit good stability. Further, the results of photocatalytic sterilization showed that the assisted dispersion of LYZ enhanced the bactericidal activity of g-C3N4 and exhibited promising application prospects in the field of biomedicine and water disinfection.
Analysis of the Feshbach–Schur method for the Fourier spectral discretizations of Schrödinger operators
Authors: Dusson Geneviève , Sigal Israel , Stamm Benjamin
Published: September 2022

In this article, we propose a new numerical method and its analysis to solve eigenvalue problems for self-adjoint Schrödinger operators, by combining the Feshbach–Schur perturbation theory with the spectral Fourier discretization. In order to analyze the method, we establish an abstract framework of Feshbach–Schur perturbation theory with minimal regularity assumptions on the potential that is then applied to the setting of the new spectral Fourier discretization method. Finally, we present some numerical results that underline the theoretical findings.
An efficient updation approach for enumerating maximal (Δ,γ)-cliques of a temporal network
Authors: Banerjee Suman , Pal Bithika
Published: September 2022

Given a temporal network $\mathcal{G}(\mathcal{V}, \mathcal{E}, \mathcal{T})$, $(\mathcal{X},[t_a,t_b])$ (where $\mathcal{X} \subseteq \mathcal{V}(\mathcal{G})$ and $[t_a,t_b] \subseteq \mathcal{T}$) is said to be a $(\Delta, \gamma)$-clique of $\mathcal{G}$, if for every pair of vertices in $\mathcal{X}$, there must exist at least $\gamma$ links in each $\Delta$ duration within the time interval $[t_a,t_b]$. Enumerating such maximal cliques is an important problem in temporal network analysis, as it reveals contact pattern among the nodes of $\mathcal{G}$. In this article, we study the maximal $(\Delta, \gamma)$-clique enumeration problem in online setting; that is, the entire link set of the network is not known in advance, and the links are coming as a batch in an iterative fashion. Suppose, the link set till time stamp $T_{1}$ (i.e. $\mathcal{E}^{T_{1}}$), and its corresponding $(\Delta, \gamma)$-clique set are known. In the next batch (till time $T_{2}$), a new set of links (denoted as $\mathcal{E}^{(T_1,T_2]}$) is arrived. Now, the goal is to update the existing $(\Delta, \gamma)$-cliques to obtain the maximal $(\Delta, \gamma)$-cliques till time stamp $T_{2}$. We formally call this problem as the Maximal $(\Delta, \gamma)$-Clique Updation Problem for enumerating maximal $(\Delta, \gamma)$-cliques. For this, we propose an efficient updation approach that can be used to enumerate maximal $(\Delta, \gamma)$-cliques of a temporal network in online setting. We show that the proposed methodology is correct, and it has been analysed for its time and space requirement. An extensive set of experiments have been carried out with four benchmark temporal network datasets. The obtained results show that the proposed methodology is efficient both in terms of time and space to enumerate maximal $(\Delta, \gamma)$-cliques in online setting. Particularly, compared to it’s off-line counterpart, the improvement caused by our proposed approach is in the order of hours and GB for computational time and space, respectively, in large dataset.
Catastrophic presentation of peripartum cardiomyopathy: a case report of a challenging diagnosis
Authors: Silva Mariana Ribeiro , Silva Gualter Santos , Caeiro Daniel , Fontes-Carvalho Ricardo
Published: September 2022

Background

Peripartum cardiomyopathy (PPCM) usually affects women in the last month of pregnancy or in the first months following delivery and typically presents with signs and symptoms of heart failure (HF), although catastrophic presentations may be the initial manifestation.

Case summary

A 36-year-old woman reported intense fatigue that began after delivery. Three months following delivery, she suffered a cardiac arrest at home, in shockable rhythm, with a total estimated time of 70 min before return of spontaneous circulation. Electrocardiogram presented diffuse ST-segment depression and transthoracic echocardiography showed severe left-ventricle (LV) dysfunction with global hypokinesis. In the catheterization laboratory, she underwent a triple rule out (no aortic, coronary, or pulmonary vascular disease); ventriculography was not suggestive of Takotsubo syndrome. She was transferred to the cardiac intensive care unit, under invasive mechanical ventilation and vasopressor support. A presumptive diagnosis of PPCM was made and bromocriptine and heparin were started. In three days, she was weaned from haemodynamic support and extubated, with good neurologic outcome. Cardiac magnetic resonance showed no signs of inflammation or fibrosis. Cardiomyopathy genetic test was negative. PPCM diagnosis was assumed, HF therapy was introduced and a cardioverter-defibrillator was implanted. At 2.5 months follow up, she presented HF NYHA Class II and recovered LV function.

Discussion

We present a case of a woman, three months after delivery, who developed a catastrophic manifestation of PPCM. This case raises awareness about atypical presentations of PPCM, whose diagnosis should be considered in the appropriate clinical context, but ultimately, remains a diagnosis of exclusion.