bluuebunny/crossref_metadata_2025 huggingface dataset:
Orofacial Pain, Musical Performance and Associated Coping Behaviors, Psychological Distress and Disability among Asian Young Adults
Authors: Nair Rahul , Tanikawa Chihiro , Ferreira Joao N.
Published: February 2023

Musicians often report orofacial pain (OFP) and performance-related psychological distress related to occupational neuromuscular overuse, but to date, no study has been performed in Asian musicians to assess these factors. This study evaluated OFP, psychological distress, coping behaviors, and disability among Asian musical performers. A total of 201 participants in Singaporean music ensembles were surveyed from which 159 met the inclusion criteria for vocalists or instrumentalist musicians (mean age 20.26 ± 2.20 years). Self-administered questionnaires assessed musical practices, jaw/neck pre-conditioning exercises, pain-related temporomandibular disorders (TMD), OFP descriptors, pain chronicity and disability, coping behaviors and psychological distress. Univariate and multi-variate analyses were carried out. OFP, while performing, was more than two-fold higher in instrumentalists when compared to vocalists (41.4–48% vs. 17.2%, p = 0.002). A similar trend occurred for OFP that progresses while playing (p = 0.035) and for persistent OFP that reduces playing (p = 0.001). There were no differences in psychological distress, pain coping and disability between groups. Vocalists were found to practice jaw/neck pre-conditioning exercises more frequently (75% vs. 4–12.9% in instrumentalists, p < 0.0001). While performing, Asian vocalists reported less OFP when compared to instrumentalists. Future prospective studies are needed to confirm if pre-conditioning exercises play a protective role against OFP in vocalists.
Hospital Readmission Risk and Risk Factors of People with a Primary or Secondary Discharge Diagnosis of Diabetes
Authors: Rubin Daniel J. , Maliakkal Naveen , Zhao Huaqing , Miller Eli E.
Published: February 2023

Hospital readmission among people with diabetes is common and costly. A better understanding of the differences between people requiring hospitalization primarily for diabetes (primary discharge diagnosis, 1°DCDx) or another condition (secondary discharge diagnosis, 2°DCDx) may translate into more effective ways to prevent readmissions. This retrospective cohort study compared readmission risk and risk factors between 8054 hospitalized adults with a 1°DCDx or 2°DCDx. The primary outcome was all-cause hospital readmission within 30 days of discharge. The readmission rate was higher in patients with a 1°DCDx than in patients with a 2°DCDx (22.2% vs. 16.2%, p < 0.01). Several independent risk factors for readmission were common to both groups including outpatient follow up, length of stay, employment status, anemia, and lack of insurance. C-statistics for the multivariable models of readmission were not significantly different (0.837 vs. 0.822, p = 0.15). Readmission risk of people with a 1°DCDx was higher than that of people with a 2°DCDx of diabetes. Some risk factors were shared between the two groups, while others were unique. Inpatient diabetes consultation may be more effective at lowering readmission risk among people with a 1°DCDx. These models may perform well to predict readmission risk.
Heart Failure Association-International Cardio-Oncology Society Risk Score Validation in HER2-Positive Breast Cancer
Authors: Cronin Michael , Crowley Aileen , Davey Matthew G. , Ryan Peter , Abdelshafy Mahmoud , Elkoumy Ahmed , Elzomor Hesham , Arsang-Jang Shahram , Ganly Sandra , Nash Patrick , Crowley James , Sharif Faisal , Simpkin Andrew , Lowery Aoife , Wijns William , Kerin Michael , Soliman Osama
Published: February 2023

Background: This paper looks to validate the risk score from the Heart Failure Association of the European Society of Cardiology and the International Cardio-Oncology Society (HFA-ICOS) for predicting potential cardiotoxicity from anticancer therapy for patients positive for human epidermal growth factor receptor 2. Methods: A total of 507 patients with at least five years since index diagnosis of breast cancer were retrospectively divided according to the HFA-ICOS risk proforma. According to level of risk, these groups were assessed for rates of cardiotoxicity via mixed-effect Bayesian logistic regression model. Results: A follow-up of five years observed cardiotoxicity of 3.3% (n = 3) in the low-risk, 3.3% (n = 10) in the medium-risk, 4.4% (n = 6) in the high-risk, and 38% (n = 6) in the very-high-risk groups respectively. For cardiac events related to treatment, the risk was significantly higher for the very-high-risk category of HFA-ICOS compared to other categories (Beta = 3.1, 95% CrI: 1.5, 4.8). For overall cardiotoxicity related to treatment, the area under the curve was 0.643 (CI 95%: 0.51, 0.76), with 26.1% (95% CI: 8%, 44%) sensitivity and 97.9% (95% CI: 96%, 99%) specificity. Conclusions: The HFA-ICOS risk score has moderate power in predicting cancer therapy–related cardiotoxicity in HER2-positive breast cancer patients.
Heterogeneity of Ocular Hemodynamic Biomarkers among Open Angle Glaucoma Patients of African and European Descent
Authors: Siesky Brent , Harris Alon , Verticchio Vercellin Alice , Arciero Julia , Fry Brendan , Eckert George , Guidoboni Giovanna , Oddone Francesco , Antman Gal
Published: February 2023

This study investigated the heterogeneity of ocular hemodynamic biomarkers in early open angle glaucoma (OAG) patients and healthy controls of African (AD) and European descent (ED). Sixty OAG patients (38 ED, 22 AD) and 65 healthy controls (47 ED, 18 AD) participated in a prospective, cross-sectional study assessing: intraocular pressure (IOP), blood pressure (BP), ocular perfusion pressure (OPP), visual field (VF) and vascular densities (VD) via optical coherence tomography angiography (OCTA). Comparisons between outcomes were adjusted for age, diabetes status and BP. VF, IOP, BP and OPP were not significantly different between OAG subgroups or controls. Multiple VD biomarkers were significantly lower in OAG patients of ED (p < 0.05) while central macular VD was lower in OAG patients of AD vs. OAG patients of ED (p = 0.024). Macular and parafoveal thickness were significantly lower in AD OAG patients compared to those of ED (p = 0.006–0.049). OAG patients of AD had a negative correlation between IOP and VF index (r = −0.86) while ED patients had a slightly positive relationship (r = 0.26); difference between groups (p < 0.001). Age-adjusted OCTA biomarkers exhibit significant variation in early OAG patients of AD and ED.
Biochar Derived from Rice by-Products for Arsenic and Chromium Removal by Adsorption: A Review
Authors: Chatzimichailidou Stella , Xanthopoulou Maria , Tolkou Athanasia K. , Katsoyiannis Ioannis A.
Published: February 2023

Environmental pollution by arsenic (As) and hexavalent chromium (Cr(VI)) has been one of the most serious environmental problems in recent years around the world. Their presence in water is a result of both natural and anthropogenic activities, and poses serious risks to human health due to their high toxicity. Adsorption is a leading method used to remove arsenic and chromium, with biochar, a carbonaceous pyrolytic product made from various types of biomass, under low oxygen conditions, being one of the most common adsorbents due to its high surface area. Although biochar’s ability to immobilize and remove As and Cr(VI) is high, in order to increase the adsorption capacity and nutrient release potential of rice husk biochar, it is essential to select an appropriate pyrolysis and biochar modification technique. Physical or biological activation, steam/gas activation, UV irradiation, magnetization, alkali/acid treatment, and nano-modification are the main modification methods that will be discussed in this review. These modifications have led to multi-fold enhancement in adsorption/reduction capacity of As and Cr(VI), compared with plain biochar. This review provides a recent literature overview of the different biochar modification methods, as well as the factors that influence their capacity to successfully remove As and Cr(VI), along with regeneration potentials.
Tailoring Variations in the Microstructures, Linear/Nonlinear Optical, and Mechanical Properties of Dysprosium-Oxide-Reinforced Borate Glasses
Authors: Henaish Ahmed M. , Hemeda Osama M. , Arrasheed Enas A. , Shalaby Rizk M. , Ghazy Ahmed R. , Weinstein Ilya A. , Darwish Moustafa A. , Trukhanova Ekaterina L. , Trukhanov Alex V. , Trukhanov Sergei V. , Al-Hossainy Ahmed F. , Abdelhakim Nermin A.
Published: February 2023

Hybrid dysprosium-doped borate glassy samples [B-Gly/Dy]HDG (Borate Glass/Dysprosium)Hybrid Doped Glass were prepared in this study via the melt-quenching method. Its linear/nonlinear optical, photoluminescence, hardness indentation, and micro-creep properties were analyzed. The amorphous structure for all the prepared samples was confirmed from the XRD patterns. In addition, density functional theory (DFT), optimized by TD-DFT and Crystal Sleuth, was used to study the structure and crystallinity of the [B-Gly/Dy]HDG as isolated molecules and agreed with the peaks of experimental XRD patterns. Additionally, theoretical lattice types were studied using Polymorph, a content studio software, and orthorhombic Pc21b (29) and triclinic P-1 (2) structures were provided. Both mechanical and optical properties were responses to different concentrations of Dy2O3 in the glassy borate system. It was found that the length of indentation increases by increasing the load time, and the hardness decreases by increasing the load time. The stress exponent value also increased from 4.1 to 6.3. The indentation strain increases by increasing the load time. The direct optical band gap was evaluated using the Davis–Mott relation. Urbach energy and its connection to the disorder degree in materials were studied depending on the Dy2O3 concentration. The acquired optical parameters were also analyzed to determine the nonlinear refractive index as well as the linear and third-order nonlinear optical susceptibility of the investigated glass samples. The photoluminescence emission spectra were recorded, and their attributed transitions were studied. The mechanical studies showed that the hardness values increased by increasing Dy2O3 concentrations from 4160.54 to 5631.58 Mpa. The stress exponent value also increased from 4.1 to 6.3. Therefore, the higher value of stress exponent (S) is more resistant to indentation creep.
Taguchi Method Optimization of Water Absorption Behavior by Wheat Straw-Basalt Hybrid Brake Pad Composite
Authors: Yilma Worku Mamuye , Singh Balkeshwar , Asrat Getinet , Hossain Nazia
Published: February 2023

The application of biomass-derived composite material is in high demand worldwide in various commercial sectors, including automotive, due to its durable, cost-effective, and environment-friendly characteristics. However, one of the limiting factors of biomass-based composites is its higher water absorption capacity compared to commercial synthetic composites. Therefore, this study aimed to optimize the water absorption capacity of biomass-based, wheat straw fiber-basalt hybrid composite brake pad using the Taguchi method by considering the particle size and volume % of the composite compositions. The composite synthesized in this study carried two variations of particle sizes of basalt, wheat straw, steel, river sand, and graphite, as well as two-volume percentages of epoxy resin for optimization. All composites were molded using a compression molding process at compressive pressure of 6 MPa for 2 h curing in a forced convection oven at 100 °C. Water absorption capacity has been determined according to ASTM D570. The wheat straw fiber has been chemically treated with 5 wt.% of sodium hydroxide (NaOH) to remove the impurities, lignin, and hemicellulose and increase the surface area of the fiber, resulting in a larger area of contact between the fiber and the matrix. Elemental analysis, crystallinity, morphology, and mechanical strength of wheat straw fiber-based composites have been determined by XRD, SEM, and compression tests, respectively. The statistical method, analysis of variance (ANOVA), was implemented for Taguchi optimization of the composite compositions. The maximum compressive strength and minimum and maximum water absorption capacity of composites were obtained as 77 MPa, 3.55%, and 26.86%, respectively. From the optimum setting of the confirmation experiment, the optimal water absorption value of 5.718% has been obtained. The optimum particle size of the composite compositions was 1 mm basalt particle, 0.5 mm wheat straw fiber, 1 mm steel particle, 1 mm river sand, 0.5 mm graphite dust particle, and 30 vol% epoxy resin by Taguchi method. The parameter impact of Taguchi ranking on water absorption capacity presented the maximum improvement of water absorption, 10.47%, with river sand particle size.
Tensile Response of Fibre-Reinforced Plastics Produced by Additive Manufacturing for Marine Applications
Authors: Scattareggia Marchese Simone , Epasto Gabriella , Crupi Vincenzo , Garbatov Yordan
Published: February 2023

The present study makes a consistent attempt to evaluate promising additive manufacturing (AM) processes and materials for marine structural applications, paving the way for the development of additively manufactured light-weight composites. The main objective is to analyse the structural performances of fibre-reinforced plastics (FRP) produced by AM for marine applications. In particular, the tensile response of chopped and continuous carbon-fibre-reinforced thermoplastics have been investigated through destructive and non-destructive testing, considering the influence of AM process settings and thermal post-manufacturing treatments. The results demonstrate that continuous fibre-reinforced thermoplastics produced by AM are potentially suited to marine structural applications, since their tensile capacity is superior to the minimum imposed by the Classification Society Rules. However, the mechanical properties of additively manufactured FRP are currently lower than conventional composites. The continuous carbon fibre reinforcement is far more effective than the chopped one, and the additive manufacturing deposition pattern significantly influences the structural capacity. The annealing post-manufacturing treatment enhances the mechanical properties by approximately 10%, decreasing material ductility and manufacturing defects.
A New Control Algorithm to Increase the Stability of Wind–Hydro Power Plants in Isolated Systems: El Hierro as a Case Study
Authors: Marrero Agustín , González Jaime , Carta José A. , Cabrera Pedro
Published: February 2023

The present paper proposes the implementation of a new algorithm for the control of the speed regulators of Pelton wheel turbines, used in many of the pumped hydroelectric energy storage systems that operate in isolated electrical systems with high renewable energy participation. This algorithm differs substantially from the standard developments which use PID or PI governors in that, in addition to acting on the nozzle needles and deflectors, it incorporates a new inner-loop pressure stabilization circuit to improve frequency regulation and dampen the effects of the pressure waves that are generated when regulating needle position. The proposed algorithm has been implemented in the Gorona del Viento wind–hydro power plant, an installation which supplies the primary energy needs of the island of El Hierro (Canary Islands, Spain). Although, as well as its wind and hydro generation systems, the plant also has a diesel engine based generation system, the validation of the results of the study presented here focuses on situations in which frequency control is provided exclusively by the hydroelectric plant. It is shown that implementation of the proposed algorithm, which replaces the previous control system based on a classical PI governor, is able to damp the pressure wave that originates in the long penstock of the plant in the face of variations in non-dispatchable renewable generation, a situation which occurred with a high degree of relative frequency in the case study. The damper has enabled a substantial reduction in the cumulative time and the number of times that frequency exceeded different safety margins. Damper incorporation also reduced the number of under-frequency pump unit load shedding events by 93%.
RANS-Based Modelling of Turbulent Flow in Submarine Pipe Bends: Effect of Computational Mesh and Turbulence Modelling
Authors: Yang Qi , Dong Jie , Xing Tongju , Zhang Yi , Guan Yong , Liu Xiaoli , Tian Ye , Yu Peng
Published: February 2023

Pipe bend is a critical integral component, widely used in slurry pipeline systems involving various engineering applications, including natural gas hydrate production. The aim of this study is to assess the capability of RANS-based CFD models to capture the main features of the turbulent single-phase flow in pipe bends, in view of the future investigation of the hydrate slurry flow in the same geometry. This is different from the available literature in which only a few accounted for the effects of a combination of computational mesh, turbulence model, and near-wall treatment approach. In this study, three types of mesh configuration were adopted to carry out the computations, namely unstructured mesh and two structured meshes with a uniform and nonuniform inflation layer, respectively. To explore the influence of the turbulence model, standard k-ε, low-Reynolds k-ε, and nonlinear eddy viscosity turbulence model were selected to close RANS equations. Pressure coefficient, mean axial velocity, turbulence intensity, secondary flow velocity, and magnitude of secondary flow were regarded as the critical variables to make a comprehensive sensitivity analysis. Predicted results suggest that turbulent kinetic energy is the most sensitive variable to the computational mesh while others tend to stabilize. The largest difference of turbulence kinetic energy was around 26% between unstructured mesh and structured mesh with a nonuniform inflation layer. Additionally, a fully resolved boundary layer can reduce the sensitivity of mesh on turbulent kinetic energy, especially for a nonlinear turbulence model. However, the large gradient and peak value of turbulence intensity near the inner wall of the bend was not captured by the case with a fully resolved boundary layer, compared with that of the wall function used. Furthermore, it has been confirmed that the same rule was detected also for different curvature ratios, Reynolds numbers, and dimensionless wall distance y+.
Path Planning for Ferry Crossing Inland Waterways Based on Deep Reinforcement Learning
Authors: Yuan Xiaoli , Yuan Chengji , Tian Wuliu , Liu Gan , Zhang Jinfen
Published: February 2023

Path planning is a key issue for safe navigation of inland ferries. With the development of ship intelligence, how to enhance the decision–support system of a ferry in a complex navigation environment is one of the key issues. The inland ferries need to cross the channel frequently and, thus, risky encounters with target ships in the waterway are more frequent, so they need an intelligent decision–support system that can deal with complex situations. In this study, a reinforced deep learning method is proposed for path planning of inland ferries during crossing of the waterways. In the study, the state space, action space and reward function of the Deep Q-network (DQN) model are designed and improved to establish an autonomous navigation method for ferries considering both economy and safety. The DQN model also takes into account the crossing behavior, navigation economy and safety. Finally, the model is applied to case studies to verify its effectiveness.
Hydrocarbon Accumulation Analysis Based on Quasi-3D Seismic Data in the Turbulent Area of the Northern South China Sea
Authors: Zhao Zhongquan , Zhong Guangjian , Sun Ming , Feng Changmao , Tu Guanghong , Yi Hai
Published: February 2023

The Mesozoic strata in the northern South China Sea have good potential for oil and gas exploration. The Dongsha Waters, where the study area is located, have complex seismic and geological characteristics; in particular, turbulence is very prominent in this area, so it is difficult to implement 3D seismic data collection. The “single-source and single-cable quasi-3D seismic survey” method integrates some key technologies in acquisition and processing, thus improving the quality of seismic imaging. Based on the interpretation of the existing research results and new data, structure B-1 has good source–reservoir–cap combination conditions. The oil–gas accumulation mode is predicted, and the drilling well B-1-1 is given. In addition, the large-scale distribution of bottom-simulating reflectors (BSRs) and the discovery of gas seepage areas in the study area suggest the presence of gas hydrate. We suggest that deep thermogenic gas from the Mesozoic strata has migrated into the overlying strata along the fault system and mixed with microbial gas to form hydrate.
Sea-Surface Small Target Detection Based on Four Features Extracted by FAST Algorithm
Authors: Zhao Di , Xing Hongyan , Wang Haifeng , Zhang Huaizhou , Liang Xinyi , Li Haoqi
Published: February 2023

On account of current algorithm and parameter design difficulties and low detection accuracy in feature extractions of small target detections in sea clutter environment, this paper proposes a correspondingly improved four feature extraction method by FAST. After the short-time Fourier transform is applied, a time–frequency distribution spectrogram of original data is generated. Candidate feature points (CFP) are first extracted by FAST algorithm, and then a four-feature extraction is implemented with FAST and DBSCAN combined. The feature distinction is enhanced through a feature optimization. Upon the construction of the four-dimensional feature vectors, XGBoost classifier algorithm classifies and detects these feature vectors. The genetic algorithm optimizes the hyperparameters in XGBoost and updates the decision threshold in real time to control the detection method’s false alarm rate. The IPIX dataset is employed for experimental verification. Verification results confirm that this proposed detection method has better performance than several other currently used detection methods. The detection performance is improved by 7% and 13.8% when observation time is set at 0.512 s and 1.024 s, respectively.
Reconstruction Methods in Oceanographic Satellite Data Observation—A Survey
Authors: Ćatipović Leon , Matić Frano , Kalinić Hrvoje
Published: February 2023

Oceanographic parameters, such as sea surface temperature, surface chlorophyll-a concentration, sea surface ice concentration, sea surface height, etc., are listed as Essential Climate Variables. Therefore, there is a crucial need for persistent and accurate measurements on a global scale. While in situ methods tend to be accurate and continuous, these qualities are difficult to scale spatially, leaving a significant portion of Earth’s oceans and seas unmonitored. To tackle this, various remote sensing techniques have been developed. One of the more prominent ways to measure the aforementioned parameters is via satellite spacecraft-mounted remote sensors. This way, spatial coverage is considerably increased while retaining significant accuracy and resolution. Unfortunately, due to the nature of electromagnetic signals, the atmosphere itself and its content (such as clouds, rain, etc.) frequently obstruct the signals, preventing the satellite-mounted sensors from measuring, resulting in gaps—missing data—in satellite recordings. One way to deal with these gaps is via various reconstruction methods developed through the past two decades. However, there seems to be a lack of review papers on reconstruction methods for satellite-derived oceanographic variables. To rectify the lack, this paper surveyed more than 130 articles dealing with the issue of data reconstruction. Articles were chosen according to two criteria: (a) the article has to feature satellite-derived oceanographic data (b) gaps in satellite data have to be reconstructed. As an additional result of the survey, a novel categorising system based on the type of input data and the usage of time series in reconstruction efforts is proposed.
Channel Polarization Scheme for Ocean Turbulence Channels in Underwater Visible Light Communication
Authors: Li Xiaoji , Sun Leiming , Huang Jiemei , Zeng Fanze
Published: February 2023

Underwater wireless communication technology plays an important role in marine environment monitoring and ecological protection. Underwater optical wireless communications (UWOCs) can currently achieve a transmission distance of hundreds of meters, and the rate can reach hundreds of Mbps or even Gbps, with low power consumption and high-speed features. In addition, UWOC also has the advantages of a small transceiver size and strong anti-electromagnetic interference ability, which is especially suitable for scenarios where underwater volume and power consumption are relatively limited. However, UWOC systems face problems such as unstable transceiver ends, ocean turbulence, and so on, resulting in reduced communication reliability and limited transmission distance. Establishing a stable and reliable communication link is critical to extending the communication distance of the UWOC system. In this paper, a model of ocean turbulence channels is established based on the power spectrum inversion method. The transmission characteristics of orbital angular momentum (OAM) light in an ocean turbulence channel are studied, then the mode selection of OAM light is determined. At the same time, the polarization coding technique is applied to the underwater OAM communication system for the first time. The simulation results show that this scheme can effectively extend the communication distance and reduce the system bit error rate.
Simulating the Impacts of an Applied Dynamic Adaptive Pathways Plan Using an Agent-Based Model: A Tauranga City, New Zealand, Case Study
Authors: Allison Andrew , Stephens Scott , Blackett Paula , Lawrence Judy , Dickson Mark Edward , Matthews Yvonne
Published: February 2023

Climate change and relative sea-level rise (RSLR) will increasingly expose coastal cities to coastal flooding, erosion, pluvial and fluvial flooding, episodic storm-tide flooding and eventually, permanent inundation. Tools are needed to support adaptive management approaches that allow society to adapt incrementally by making decisions now without creating path dependency and compromising decision-making options in the future. We developed an agent-based model that integrates climate-related physical hazard drivers and socio-economic drivers. We used it to explore how adaptive actions might be sequentially triggered within a low-elevation coastal city in New Zealand, in response to various climate change and socio-economic scenarios. We found that different adaptive actions are triggered at about the same RSLR level regardless of shared socio-economic pathway/representative concentration pathway scenario. The timing of actions within each pathway is dictated mainly by the rate of RSLR and the timing and severity of storm events. For the representative study site, the model suggests that the limits for soft and hard protection will occur around 30 cm RSLR, fully-pumped water systems are viable to around 35 cm RSLR and infrastructure upgrades and policy mechanisms are feasible until between 40 cm and 75 cm RSLR. After 75 cm RSLR, active retreat is the only remaining adaptation pathway.
Object Extraction Algorithm for the First-Frame Image of Unmanned Surface Vehicles Based on a Radar-Photoelectric System
Authors: Yu Qingze , Su Yumin , Zhang Renran
Published: February 2023

The radar-photoelectric system is a perception system to detect the surrounding environment based on marine radar and a photoelectric device. Mast obscuration, green water, and multi-object scenes are special scenes that appear in the first-frame image during the navigation of unmanned surface vehicles. The perception system cannot accurately obtain the object information in mast obscuration and green water scenes. The radar-guided object cannot be stably extracted from the first-frame image in multi-object scenes. Therefore, this paper proposes an object extraction algorithm for the first-frame image of unmanned surface vehicles based on a radar-photoelectric system. The algorithm realizes the field-of-view adaptation to solve the problem that the features of the radar-guided object are incomplete in the first-frame image and improve the detection accuracy of the local features by 16.8%. The algorithm realizes the scene recognition of the first-frame image to improve the robustness of object tracking. In addition, the algorithm achieves the stable extraction of the radar-guided object in multi-object scenes.
Fatigue Strength of AH36 Thermal Cut Steel Edges at Sub-Zero Temperatures
Authors: Beiler Marten , Grimm Jan-Hendrik , Bui Trong-Nghia , von Bock und Polach Franz von Bock und , Braun Moritz
Published: February 2023

Cruise ships or yachts that operate in areas with seasonal freezing temperatures have large openings in the outer shell. Those are thermal cut edges, and they are exposed to very low temperatures. From fatigue crack growth testing of base materials, it is known that low temperatures can accelerate the crack growth, which may reduce the fatigue life of a structure. However, the current guidelines and rules of classification societies do not provide design curves for the fatigue assessment of thermal cut steel edges at sub-zero temperatures. Therefore, fatigue tests of thermal cut edges are conducted at −20 ∘C and −50 ∘C as well as at room temperatures for reference. The specimens are plasma-cut and tested in a temperature chamber under uniaxial loading with a resonant testing machine. The test results are statistically evaluated using linear regression and the maximum likelihood method. The results show that the fatigue strength at sub-zero temperatures is significantly higher compared to room temperature. The test results of this study indicate that sub-zero temperatures down to −50 ∘C do not seem to cause a reduced fatigue life of thermal cut steel edges.
A Novel Variable Weight VIKOR Grade Assessment Method for Waterway Navigation Safe Routes Selection
Authors: Yu Gao-Feng , Lin Yu-Jin , Luo Xiao-Mei
Published: February 2023

According to the characteristics of waterway navigation safe routes selection, and considering the individual feelings and group benefits of information, as well as no-compensation information between indexes, this paper describes the safe rating of waterway navigation routes, and then puts forward an evaluation model of and method for waterway navigation safe route selection based on variable weight VIKOR. First of all, from the concept and connotation of grade assessment, this paper describes the safe rating of waterway navigation routes, so as to avoid confusing the two essential different problems of safe rating and ranking. Then, the evaluation indexes and membership function of the appropriate grade of the safe rating of waterway navigation route are constructed, and the weights of an evaluation index based on entropy are proposed. Secondly, a variable weight VIKOR evaluation model and a binary semantic evaluation method for the safe grading of waterway navigation safe routes are proposed. Finally, through case study and comparative analysis, the rationality and feasibility of the model and method proposed in this paper are illustrated. This model can better reflect the connotation and characteristics of the appropriate grade assessment of waterway navigation safe routes, and provides new approaches and methods to support the development and management of waterway navigation safe route selection.
Anomalous Coloration of Indo-Pacific Humpback Dolphins off Southern China
Authors: Lin Wenzhi , Chen Shenglan , Zheng Ruiqiang , Serres Agathe , Liu Binshuai , Lin Mingli , Liu Mingming , Li Songhai
Published: February 2023

The Indo-Pacific humpback dolphin is characterized by a particular ontogenic change in body color from dark gray at birth to pure white (or with a few dark-gray spots) after reaching adulthood. Here, we report a spectrum of anomalous body color patterns observed on Indo-Pacific humpback dolphins off southern China. The occurrence of hypopigmentation and hyperpigmentation was described and compared among six putative dolphin populations. Low rates of anomalies in body color patterns were observed (<1%), except for hypopigmentation, which was prevalent in dolphins residing in the mid-Pearl-River-Delta region (3.3%).
Assessment of Hydrodynamic Loads on an Offshore Monopile Structure Considering Hydroelasticity Effects
Authors: Thome Michael , el Moctar Ould , Schellin Thomas E.
Published: February 2023

Regular and irregular waves were numerically generated in a wave canal to investigate hydrodynamic loads acting on a wind turbine monopile and to predict its structural response. The monopile was implemented in the canal and modeled as a flexible structure, with the turbine blades and rotors considered as a point mass situated at the top of the monopile. Fluid–structure interaction (FSI) simulations were performed by coupling a structure solver based on a finite element method (FEM) with an unsteady Reynolds-averaged Navier–Stokes (URANS) equations solver of the finite volume method (FVM). The FSI simulations considered the two-way interaction between the deformable structure and the fluid flow. The URANS equations solver was coupled with the volume of fluid (VoF) method to account for the two-phase flow. In regular waves, numerically predicted total load coefficients occurring at the monopile’s first eigenfrequency compared favorably to experimental measurements. A deviation between calculations and measurements was observed for the total loads in irregular waves. This deviation occurred due to the smaller wave energy density of the numerically predicted irregular wave. Hydroelasticity effects increased wave-induced forces by about 6% and wave induced bending moments by about 16% in regular waves. A relatively strong whipping event was observed, which characterized the hydroelasticity response bending moment of the monopile in irregular long-crested waves. This whipping event also had a significant influence on the loads on the monopile. These investigations demonstrated the favorable use of FSI simulations to predict hydroelasticity effects on a monopile.
Sensitivity Analysis of Risk Characteristics of Complex Engineering Systems: An Application to a Subsea Pipeline Monitoring System
Authors: Rykov Vladimir , Kochueva Olga , Farkhadov Mais , Zaripova Elvira , Zhaglova Anna
Published: February 2023

One of the problems of risk analysis of complex engineering systems is the uncertainty of initial information about the time and damage associated with occurrence and development of the risk situation. The paper proposes a methodology and procedure for constructing a risk tree, loading it with initial data, calculating the corresponding characteristics: the distributions of time to reach the intermediate and main risk events and of associated with them damages, as well as their moments. Methodology involves the construction of the most dangerous path of risk situation development with respect to different criteria as well as analysis the sensitivity of risk characteristics to the initial information. The proposed approach is applied to a model of an automated system for remote monitoring of underwater gas pipeline. The proposed methodology and its implementation on a real-world example constitute the novelty of the work.
Integration of a Geothermal Plant in a System with High Renewable Energy Penetration for Desalination Plant Self-Consumption
Authors: Montesdeoca-Martínez Fernando , Velázquez-Medina Sergio
Published: February 2023

The scarcity of water resources on the island of Gran Canaria (Canary Islands, Spain) is such that 88% of the water supply for human consumption comes from seawater desalination plants. This type of process has a high specific energy consumption. Gran Canaria has an isolated electrical system of low robustness. In this paper, a geothermal plant is designed and integrated into a system that already has non-dispatchable renewable generation (wind and photovoltaic) in order to meet, based on a self-consumption regime, the energy demand of a high-capacity desalination plant. The aim is for the diversified renewable system to improve the stability and management of renewable electrical energy generation. Geothermal plant production can adapt to the energy balance between demand and non-dispatchable renewable generation. The geothermal plant’s design is based on an organic Rankine cycle and its resulting power is 4.16 MW. Its integration in the renewable generation system significantly improves the contribution of renewables in meeting the desalination plant’s energy demand and therefore reducing its dependency on the island’s electrical system. The mean cost of electrical energy generation with the diversified renewable system is 57.37 EUR/MWh, considerably lower than the mean cost of conventional generation on Gran Canaria of 153.9 EUR/MWh.
A Study on Grid-Cell-Type Maritime Traffic Distribution Analysis Based on AIS Data for Establishing a Coastal Maritime Transportation Network
Authors: Kim Hyun-Suk , Lee Eunkyu , Lee Eui-Jong , Hyun Jin-Won , Gong In-Young , Kim Kyungsup , Lee Yun-Sok
Published: February 2023

Recently, marine development plans such as offshore wind farms and marina port facilities have been established to use Korean coastal waters, and research on the development of operational ships such as autonomous ships and water-surface flying ships is being rapidly promoted. Since the marine traffic in Korean coastal waters is expected to increase, the government intends to construct a coastal maritime transportation network that connects Korean coastal waters to guarantee safe ship navigation. Therefore, this study used automatic-identification-system data analysis to obtain quantitative evaluation results on maritime traffic distribution characteristics and utilization levels for the entire Korean coastal waters in grid cell for greater consistency and compatibility. The characteristics of marine traffic distribution at a certain site in coastal Korean waters can be quantitatively examined using the findings of this study, and they may be used as grid-cell-type data-based information. Moreover, the vessel traffic index allows for extensive research while quickly understanding the present level of use of the passing ships by the sea area. In this regard, the findings of this study are expected to be useful for the future development of maritime transportation networks in Korean coastal waters.
Laboratory Studies of Internal Solitary Waves Propagating and Breaking over Submarine Canyons
Authors: Lin Ying-Tien , Liu Ling , Sheng Biyun , Yuan Yeping , Hu Keke
Published: February 2023

This paper carried out laboratory experiments to study evolution of internal solitary waves (ISWs) over submarine canyons with a combination of PIV (particle image velocimetry) and PLIF (planar laser-induced fluorescence) techniques. Taking canyon angle θ and collapse height ∆H as variables, Froude number Fr, head position, energy loss, vorticity field and turbulence intensity when ISWs propagate to the canyon were analyzed. According to the Froude number Fr values, the study cases can be divided into three types: Fr > 1.7 means complete internal hydraulic jump (IHJ); 1 < Fr < 1.7 denotes wavy IHJ and Fr < 1 represents no IHJ. The greater canyon angle, collapse depth and amplitude of the incident wave more easily generate IHJs, which can lead to more energy loss, greater vorticity and turbulence intensity in the canyon area. Among all canyon cases, vorticity and turbulence intensity of the no IHJ case showing an obvious bimodal distribution are smaller than IHJ cases. For wavy IHJ, the energy dissipation is not obvious, and the average turbulent intensity performs a “sharp unimodal distribution”. Complete IHJ cases last for a long time and cause violent mixing, the average turbulent intensity is the largest and its distribution presents a “gentle single peak” pattern. For the 180° conditions (no canyon cases), less energy is delivered to the reflected wave and more energy is dissipated near the terrain, so the energy loss is the largest in comparison to other conditions. These findings will deepen our understanding of the evolution mechanisms of ISWs propagating over submarine canyons.
Strong Genetic Structure and Limited Gene Flow among Populations of the Tropical Seagrass Thalassia hemprichii in the Philippines
Authors: Nakajima Yuichi , Matsuki Yu , Fortes Miguel D. , Uy Wilfredo H. , Campos Wilfredo L. , Nadaoka Kazuo , Lian Chunlan
Published: February 2023

Seagrasses are marine angiosperms, and seagrass beds maintain the species diversity of tropical and subtropical coastal ecosystems. For proper understanding, management and conservation of coastal ecosystems, it is essential to understand seagrass population dynamics. Population genetic studies can cover large geographic scales and contribute to a comprehensive understanding of reproductive dynamics and potential dispersal among locations. The clonal and genetic diversity and genetic connectivity of Thalassia hemprichii in the Philippines were estimated by a population genetics approach. The geographic scale of this study has a direct distance of approximately 1600 km. Although high clonal diversity was found in some sites (R = 0.07–1.00), both sexual and asexual reproduction generally maintains separate populations. Genetic diversity is not definitely correlated with latitude, and genetic differentiation is significant in all pairs of sites (FST = 0.026–0.744). Complex genetic structure was found in some regions, even at a fine geographic scale. The migration of fruits and seedlings was elucidated as an infrequent and stochastic event. These results suggest the necessity for the conservation of this species due to a deficiency in migrants from external regions.
Weak Underwater Acoustic Target Detection and Enhancement with BM-SEED Algorithm
Authors: Yin Fan , Li Chao , Wang Haibin , Nie Leixin , Zhang Yonglin , Liu Chaonan , Yang Fan
Published: February 2023

Bearing time record (BTR) is widely used in the field of passive sonar information processing for target detecting and tracking. One of its challenges is to obtain high-resolution beamforming power spectral to facilitate the directions estimating of arrivals, namely DOA estimating. This paper proposes a new algorithm framework Block Matching - Subband Extrema Energy Detection (BM-SEED) to supplement the resolution and enhance the weak targets of BTRs. It extracts the peak features of target trajectories within the conventional beamforming (CBF)-based BTRs by using an improved sub-band peak energy detection (SPED) algorithm, and then enhances the weak targets and suppresses the false-alarm targets through time-spatial autocorrelation analysis. Simulations and sea-trial data evaluations demonstrate that the method of this paper can enhance weak targets, eliminate the interferences of false targets and improve the resolution of BTR targets to 1 degree under −20 dB.
Optimization of Waypoints on the Great Circle Route Based on Genetic Algorithm and Fuzzy Logic
Authors: Hsieh Tsung-Hsuan , Meng Qian , Han Bing , Wang Shengzheng , Wu Xuezhen
Published: February 2023

Determining the appropriate number and position of waypoints on a great circle route (GCR) helps to shorten the sailing distance, reduce the number of course changes, and well-approximate the GCR through a small number of rhumb line (RL) legs. In this study, a genetic algorithm-based method (i.e., the GA method) is proposed to optimize the positions of waypoints on the GCR when the number of waypoints is given. Furthermore, a fuzzy logic-based evaluation method for the number of waypoints (i.e., the FL method) is proposed to judge whether to add a new waypoint or stop the process by using the non-fixed values while considering both the number of waypoints and the remaining benefit of the GCR. According to the example demonstration results, the two methods proposed in this study can well-determine the number and position of waypoints and provide effective support for ocean route planning.
Extreme Heavy Rainfall Events at Mid-Latitudes as the Outcome of a Slow Quasi-Resonant Ocean—Atmosphere Interaction: 10 Case Studies
Authors: Pinault Jean-Louis
Published: February 2023

Based on case studies, the development of low-pressure systems leading to extreme precipitation events reveals common characteristics. They highlight the co-evolution of sea surface temperature (SST) anomalies and the clustering of mesoscale convective systems in characteristic period ranges according to harmonic modes of the annual declination of the sun. This suggests a quasi-resonance of the heat exchanges of the ocean and the atmosphere during cyclogenesis. The formation of coherent extensive positive SST anomalies in characteristic period ranges, which reflects various interactions from baroclinic waves at mid-latitudes, i.e., Rossby waves especially present where the western boundary currents move away from the continents, may be a precursor of an extreme heavy rainfall event. Fed by warm and humid air coming from coherent SST anomalies, the convective cyclonic system strengthens concomitantly with the formation of cut-off lows, favoring blocks. However, the concentration in space and time of large-amplitude rainfall anomalies requires a relative stability of the atmospheric blocking circulation during the slow maturation processes. Intensification of extratropical cyclones is presumably the consequence of natural and anthropogenic warming, which strengthens the mechanisms leading to the clustering of mesoscale convective systems. The present study should help to refine the prediction of these extreme events while contributing to enrich our understanding of their presumed link with global warming.
MicroRNA-Mediated Responses: Adaptations to Marine Extreme Environments
Authors: De Falco Gabriele , Lauritano Chiara , Carrella Sabrina
Published: February 2023

Extreme environments are characterized by peculiar conditions, such as hypoxia/anoxia, freezing/heat temperatures, and desiccation. With climate change, more and more habitats are facing extreme conditions and living communities are finding ways to adapt in order to survive. In this study, we show several species which have been shown to adapt to marine extreme conditions also via miRNA-mediated responses. miRNAs are a class of small non-coding RNAs that mediate gene regulation via interactions with transcripts. Their action can directly or indirectly regulate pathways that can result in a response to a specific condition. Furthermore, the study of these miRNA-mediated responses could help in the biotechnological field for their application in the development of environmental biomarkers of stress conditions, or in the genetic engineering of algal species for the production of high-value compounds.