bluuebunny/crossref_metadata_2025 huggingface dataset:
Hollow law and utilitarian law: The devaluing of deportation hearings in New York City and Paris
Authors: Dao Lili
Published: September 2023

How is law made worthless to the marginalized? Drawing on ethnographic observations in Paris and New York City, I establish a typology of devaluation practices in deportation hearings. I analyze how informal court practices devalue court actors, the hearing, and the law itself. Despite different levels of formal protections for migrants, deportation adjudication is pared down and devalued in both cities. This devaluation, however, followed distinct logics. New York hearings were characterized by a utilitarian law logic, where process and ritualistic elements deemed inessential were shed, leaving a stripped-down core focused on case processing. The minimal protections available to migrants were weakened further. By contrast, hollow law emerged in Parisian hearings, where everyday court practices eroded the more generous protections granted to migrants through formal law. While analyses of immigration adjudication have focused on decision-making, determinants of legal outcomes, and the interpretation of formal criteria, I instead conceptualize the courtroom as a space where value is actively unmade through informal practices, drawing on insights from the sociology of valuation and evaluation.
Editors' introduction to special memorial issue honoring professor Lauren B. Edelman
Authors: Heyer Katharina , Rubin Ashley , Talesh Shauhin
Published: September 2023

The law and society community was heartbroken to learn in February 2023 that Lauren B. Edelman (“Laurie”) passed away. Laurie obtained her Bachelor of Arts degree from the University of Wisconsin before earning a Juris Doctor degree from University of California, Berkeley and a doctoral degree from Stanford University. She spent the first part of her career as a Professor at the University of Wisconsin Sociology department before joining the University of California, Berkeley Law and Jurisprudence and Social Policy program as the Agnes Roddy Robb Professor of Law and Sociology in 1996.
Laurie Edelman: Scholarship and mentorship in action
Authors: Nakamura Brent K.
Published: September 2023

My last email to Laurie Edelman, sent in September 2022, forwarded a Tenth Circuit Judicial Council Order discussing allegations against a District of New Mexico magistrate judge related to a special committee's finding that it “had reason to believe that she had engaged in sanctionable misconduct.” In letting Laurie know that this was “piece of evidence 1,000,001” that she had long “been so very correct” in her scholarship, I noted that the Order had found that many of the magistrate judge's employees chose not to report the conduct “because they feared retaliation” and still others “did not know if her behavior would constitute abusive conduct or a hostile work environment.” This was exactly what her scholarship has always described as two significant weak points in the enforcement of employment discrimination law and the realization of a fair and equitable workplace (Edelman 2016). In my mind, this September 2022 email epitomized what I had come to know—first as Laurie's former graduate student and research assistant, and now as a practicing lawyer—that Laurie was right. Her theories about endogeneity, symbolic structures, and the challenges of enforcing regulatory laws had broad applicability and this was just another instance of how, in practice, her theories and predictions proved to correctly identify real-world problems.
Metabolic‐associated fatty liver disease is associated with colorectal adenomas in young and older Korean adults
Authors: Chang Jiwon , Chang Yoosoo , Cho Yoosun , Jung Hyun‐Suk , Park Dong‐Il , Park Soo‐Kyung , Ham Soo‐Youn , Wild Sarah H. , Byrne Christopher D. , Ryu Seungho
Published: September 2023

Background and Aims

Given that the majority of colorectal cancers (CRCs) develop from high‐risk adenomas, identifying risk factors for high‐risk adenomas is important. The relationship between metabolic dysfunction‐associated fatty liver disease (MAFLD) and the risk of colorectal adenoma in young adults remains unclear. We aimed to evaluate this relationship in adults <50 (younger) and ≥50 (older) years of age.

Methods

This cross‐sectional study included 184 792 Korean adults (80% <50 years of age) who all underwent liver ultrasound and colonoscopy. Participants were grouped into those with and without MAFLD and classified by adenoma presence into no adenoma, low‐risk adenoma, or high‐risk adenoma (defined as ≥3 adenomas, any ≥10 mm, or adenoma with high‐grade dysplasia/villous features).

Results

The prevalence of low‐ and high‐risk adenomas among young and older adults was 9.6% and 0.8% and 22.3% and 4.8%, respectively. MAFLD was associated with an increased prevalence of low‐ and high‐risk adenomas in young and older adults. Young adults with MAFLD had a 1.30 (95% CIs 1.26–1.35) and 1.40 (1.23–1.59) times higher prevalence of low‐ and high‐risk adenomas, respectively, compared to those without MAFLD. These associations were consistent even in lean adults (BMI < 23 kg/m2) and those without a family history of CRC.

Conclusions

MAFLD is associated with an increased prevalence of low‐ and high‐risk adenomas in Korean adults, regardless of age or obesity status. Whether reducing metabolic risk factors, such as MAFLD, reduces the risk of precancerous lesions and ultimately reduces the risk of early‐onset CRC requires further investigation.
Impact of pre‐ablation left appendage flow velocities on long term recurrence of catheter ablation for paroxysmal atrial fibrillation
Authors: Cui Jing , Du Xin , He Liu , Xia Shi‐Jun , Tang Ri‐Bo , Sang Cai‐Hua , Long De‐Yong , Dong Jian‐Zeng , Ma Chang‐Sheng
Published: September 2023

Background

Despite undergoing a single ablation, many patients with paroxysmal atrial fibrillation (PAF) experience a gradually increasing recurrence rate. This study aims to examine the relationship between left atrial appendage emptying velocity (LAAeV) and filling velocity (LAAfV) profiles and 3‐year recurrence of AF after ablation.

Methods

We conducted a prospective study of 658 consecutive PAF patients who underwent their first ablation between January 2018 and December 2019. We collected the clinical and echocardiographic characteristics of the patients. LAAeV and LAAfV were obtained from a transesophageal echocardiogram (TEE) before catheter ablation. Patients were followed at regular intervals to monitor for the primary outcome of AF recurrence.

Results

After a median follow‐up period of 35.3 months (range, 10.7–36.3), 288 patients (43.8%) experienced AF recurrence after catheter ablation. Patients who experienced AF recurrence had decreased LAAeV and LAAfV (LAAeV: 56.5 ± 21.2 vs. 59.6 ± 20.7 cm/s, p = .052; LAAfV: 47.5 ± 17.9 vs. 51.7 ± 18.2, p = .003). Kaplan–Meier analysis showed that patients in the low LAAeV (<55 cm/s) group had a poorer event‐free survival rate than those in the high LAAeV (≥55 cm/s) group (log‐rank p = .012). Patients with LAAfV <48 cm/s had a significantly higher risk of AF recurrence than those with LAAfV ≥48 cm/s (log‐rank p = .003). In the multivariable model, low LAAfV pre‐ablation in TEE‐guided was significantly independently associated with 3‐year recurrence after single radiofrequency ablation in patients with PAF, along with LA dimension and duration of AF.

Conclusion

This study found an independent association between low LAAfV pre‐ablation in TEE‐guided and 3‐year recurrence after single radiofrequency ablation in patients with PAF.
Outcome of cancer patients after atrial fibrillation ablation: Insights from the China‐AF registry
Authors: Peng Xiaodong , He Liu , Liu Nian , Ruan Yanfei , Zhao Xin , Guo Xueyuan , Wang Wei , Li Songnan , Tang Ribo , Sang Caihua , Jiang Chenxi , Yu Ronghui , Long Deyong , Du Xin , Dong Jianzeng , Ma Changsheng
Published: September 2023

Background

Cancer has become significant comorbidity in patients with atrial fibrillation (AF). However, little is known about the efficacy and safety of AF ablation, the first‐line rhythm control strategy, in patients with cancer. This study aims to evaluate the incidence and risk of AF recurrence and safety endpoints in patients with cancer compared to the non‐cancer group after ablation.

Methods

From August 2011 to December 2020, we consecutively enrolled cancer patients in the China‐AF cohort. We used propensity score matching (1:3) to select the control group and assessed the risk of AF recurrence and adverse events after ablation in cancer patients using a multivariable Fine and Gray competing risk model.

Results

A total of 203 patients with cancer were enrolled and 21 of them were active cancer, with a median follow‐up of 12.3 months. The cumulative incidence of AF recurrence was comparable between patients with and without cancer (43.8% vs. 51.1%; p = .88). No difference in the risk of AF recurrence, thromboembolism, major bleeding, and mortality was observed after adjusting confounders. Active cancer was not associated with an increased risk of AF recurrence compared to the stable disease (SHR = 1.32; 95% CI 0.72–2.43; p = .46). Cancer was associated with a low risk of cardiovascular hospitalization (SHR, 0.54; 95% CI, 0.36–0.81; p = .01). Subgroup analysis found that hematological malignancy was associated with a high risk of AF recurrence (SHR, 5.68; 95% CI, 3.00–10.8; p < .001).

Conclusions

This study suggests that catheter ablation could be feasible for rhythm control of AF patients with concomitant cancer.
The freedom narrative and the War on Terror: Civil‐religious idolatry for the 9/11 generation
Authors: O'Leary Ryan T.
Published: September 2023

The dominant narrative by which political and military leaders justified the American War on Terror held that America was attacked on 9/11 because America is “the brightest beacon of freedom and opportunity in the world.” Today, an entire generation has been raised in the shadow of 9/11 and steeped in a dualistic and militaristic understanding of American destiny. That view of America's role in Providence is centered on a totem cult of the sacrificial soldier and makes the flag a symbol of American greatness and of freedom itself. This essay examines the “freedom narrative” as a justification of the War on Terror, analyses the cult of the sacrificial soldier as a backstop for a militaristic religious nationalism, and ultimately shows how the dominant narrative legitimating the war represents an idolatrous devolution of a more prophetic and classically republican understanding of American civil religion.
Priming seeds with salicylic acid modulates membrane integrity, antioxidant defense, and gene expression in Medicago sativa grown under iron deficiency and salinity
Authors: Boukari Nadia , Jelali Nahida , Abdelly Chedly , Hannoufa Abdelali
Published: September 2023

Exposure of plants to adverse environmental conditions reduces their growth and productivity. Currently, seed priming with phytohormones is considered one of the most reliable and cost‐effective approaches that can help alleviate the toxic effects of environmental stress. In this context, the present study aims to investigate the effect of priming alfalfa seeds with salicylic acid (SA) on oxidative stress markers, including malonyldialdehyde, protein content, activities of antioxidant enzymes, and expression of genes encoding these enzymes in leaves and roots of alfalfa (Gabes ecotype) grown under saline stress, iron deficiency, or both. Our results showed that the application of salt stress and iron deficiency separately or simultaneously induces changes in the activities of antioxidant enzymes, but these are organ‐ and stress‐dependent. The Gabes ecotype was able to increase the activities of these enzymes under salt stress to alleviate oxidative damage. Indeed, priming seeds with 100 μM SA significantly increases the enzymatic activities of APX, GPX, CAT, and SOD. Therefore, this concentration can be considered optimal for the induction of iron deficiency tolerance. Our results showed not only that Gabes ecotype was able to tolerate salt stress by maintaining high expression of the Fe‐SOD isoform, but also that the pretreatment of seeds with 100 μM SA improved the tolerance of this ecotype to iron deficiency by stimulating Fe‐SOD expression and inhibiting CAT and APXc.
“A male feminist walks into a bar, because it was set so low: The pedestal effect and the economy of gratitude in feminist spaces”
Authors: Peretz Tal
Published: September 2023

Men in feminist spaces often find themselves the recipients of disproportionate gratitude and attention—along with other persistent effects of male privilege that I have elsewhere termed the Pedestal Effect—despite this running counter to both prevailing feminist ideologies and the desires of the men themselves. Sociologist Arlie Hochschild described a similar economy of gratitude wherein low expectations led to heightened valuation of married men's household contributions, smuggling inequities from the wider society into the marriage and inhibiting progressive change even if both parties desired a more egalitarian partnership. By applying Hochschild's framework to interview data from 52 men and 12 women active in the field, I show that the same process explains the troubling continuance of male privilege in feminist spaces: while interviewees of all genders problematize the imbalanced economy of gratitude and many have attempted specific counterstrategies, it nonetheless persists in importing inequalities, undermining men's accountability, and inhibiting desired progressive change. This suggests that the economy of gratitude may be a ubiquitous interactional process that reproduces inequalities across a wide range of social contexts. I emphasize that the economy of gratitude is in fact intersectional, not only gendered, and introduce the idea of a “low bar” to more fully account for the broad range of social influences on expectation‐setting.
Analysing the impact of climate and social changes on small farms in the Italian Alps: The importance of the local scale
Authors: Whitaker Sarah H.
Published: September 2023

This article discusses how climate changes are intersecting with other environmental and social pressures to affect farmers in the Lombardy region of the central Italian Alps. Alpine areas are particularly susceptible to climate change. Natural sciences studies have documented widespread changes to weather, landscapes, and ecosystems in the Alps caused by climate and social changes, yet studies of the impact of the changes on Alpine farmers and farming practices are limited. Through semi‐structured interviews and participant observation with 40 farmers, the study demonstrates that farmers have noticed changes to the weather, ecosystems, and landscapes caused by climate and social changes. The changes are both directly affecting farming practices and intersecting with other pressures facing mountain farmers. The impact of climate change on Alpine farms varies—across even short distances—depending on the microenvironment and microclimate of the farm, the farm's degree of market integration, the personal characteristics of individual farmers, the type of agricultural activities practised, and the unique social history of the valleys under study. The article provides a window into small‐scale farming in the Alps today. As farmers respond to climate changes, they do so in a context where they are also facing myriad other challenges, some more pressing than climate change. Climate policies and programs should recognise these simultaneous challenges and be flexible to local differences in the impact of and farmer responses to change.
Evaluation for endotoxin in intraocular materials used during phacoemulsification surgery using a recombinant factor C assay
Authors: Opgenorth Taylor A. , Opgenorth Eryn L. , Eaton J. Seth , Bentley Ellison
Published: September 2023

Objective

Cataract surgery remains the sole method to resolve blindness secondary to cataract formation. One complication includes fibrin web formation post‐operatively. This study aimed to investigate the presence of endotoxin within materials used during cataract surgery as a possible cause of fibrin web phenomenon.

Methods

Preservative‐free epinephrine, heparin, viscoelastic devices, and intraocular lenses were collected for evaluation. Various manufacturers and manufacturing lot numbers were used when available. Viscosity of viscoelastics was reduced by incubating samples with human recombinant hyaluronidase. Intraocular product (IOL) packaging fluid was collected and stored for testing. The IOLs were then washed with a sterile balanced salt solution, incubated at 37°C for 48 h, and then fluid was collected for testing to mimic intraocular placement. Samples were tested using a commercially available rFC kit. Fluorescence was measured at time zero and after 1 h using a fluorescence microplate reader. The change in fluorescence was corrected for blank fluorescence and plotted to a standard curve.

Results

Endotoxin levels were below the limit of detection (0.05 EU/mL) in all samples. Incubation of IOLs at intraocular temperature did not increase extraction of endotoxin.

Conclusion

Endotoxin was not identified in any tested sample, including those used in cases of fibrin web formation post‐phacoemulsification. As fibrin webs are often observed episodically, it is possible that endotoxin levels may vary between batches, or that endotoxin is not related to fibrin formation.
Wave Dynamics Around a Floating Circular Flexible Plate Over a Permeable Bed
Authors: Gayathri R. , Tsai Chia-Cheng , Behera Harekrushna
Published: September 2023

In this paper, to determine the efficacy of the porous bed on damping far-field wave energy, the wave dynamics around a circular plate is studied. By combining the appropriate boundary conditions, the unknown potential is attained for the free surface and the plate-covered region. The Bessel series solution is attained further, by employing the matched eigenfunction expansion technique. Wave force excitation on the circular plate, deflection of the plate, and flow distribution is calculated and examined to comprehend the efficacy of the current investigation. Moreover, the motion of the plate is assessed in the time domain. The study reveals a substantial reduction in wave amplitude on the plate’s leeward side because of the energy dissipation by the porous bed. Also the study concludes that for intermediate values of porosity with larger wavenumbers, approximately 50% of wave power is dissipated with respect to incident wave power.
Hyperelastic Modelling of Elastomers for Wave Energy Convertors
Authors: Idarraga Guillermo , Yang Liu , Abad Farhad , Huang Yang , Dai Saishuai , Xiao Qing , Lotfian Saeid , Brennan Feargal
Published: September 2023

Flexible Wave Energy Converters (WECs) have gained considerable attention in recent years due to their ability to adapt to the dynamic conditions of the waves. To reach commercialization, further analyses should be done to guarantee survivability, and numerical models have been used to predict the structural response of WECs. However, the accuracy of any prediction will depend on the validity of the hyperelastic model employed and the reliability of the test data input into the chosen model. In this work, two elastomers are selected and characterised by plane stress, plane strain and biaxial stress conditions. Hyperelastic models are evaluated using ABAQUS, and hyperelastic constants are obtained for each elastomer. For the validation of the hyperelastic constants, experiments are conducted for one of the elastomers on the top of an oscillating water column (OWC) WEC. From the experiments, the deformation of the elastomeric membrane under wave conditions is obtained and compared with the results of a numerical model using the hyperelastic constants. From the results, the hyperelastic models describe well the deformation trend of the membrane on the top of the OWC, however further analysis should be done to improve the accuracy of the models.
Numerical Simulation on Gas–Liquid–Solid Three-Phase Flow by Gas-Lift Pumping System for Deep Sea Mining
Authors: Takano Satoru , Masanobu Sotaro
Published: September 2023

Subsea minerals have been found in the deep water within Japan’s exclusive economic zone. However, the development of subsea minerals has not reached the commercialization stage because many technical issues still need to be solved.

The gas-lift pumping system is one of the promising methods for subsea minerals transport. Since internal flow in pipes becomes three-phase flow for the gas-lift pumping systems, flow assurance for three-phase flow is important to design the systems for subsea minerals production.

It is necessary to figure out the liquid and solid flow rates for principal dimensions of the assumed production systems for designing and operating them. Thus, we simulated gas-liquid two-phase and gas-liquid-solid three-phase flows on the gas-lift pumping systems based on one dimensional drift flux model with reference to the previous studies, and compared the calculated results with the experimental data obtained from the previous studies. The comparison showed that the calculated transient liquid flow rates were consistent with experimental data in gas-liquid two-phase flows for the pipe of 0.026 m in internal diameter. The comparison also showed that the calculated steady liquid flow rates were consistent with the experimental data in gas-liquid-solid three-phase flows for the pipes of 0.026 m and 0.3 m. Since calculated results were generally consistent with experimental data, we could simulate gas-liquid-solid three-phase flows by the present methods. Then, we simulated the three-phase flow for the assumed actual production systems and investigated the effect of the mass flow rate of gas and the water depth of gas injection on lifting efficiency. The lifting efficiency decreased as the mass flow rate of gas increased and increased as the gas injection point approached the sea surface.
How Loads Interact? A Numerical Investigation of Aluminum Stiffened Panels Under Bi-Axial and Lateral Loads
Authors: Wang Xintong , Amdahl Jørgen
Published: September 2023

Due to low weight, aluminum alloys are commonly used to build ferries, working boats and high-speed ships. The hull of such vessels can be designed as catamaran and trimaran for favorable hydrodynamical behavior and operational purposes. Non-monohull structures are in certain areas more exposed to combined loads, such as the cross-deck subjected to the longitudinal and transverse hull bending, and water slamming. In these cases, the existing design rules predict the ultimate strength with simplified interactions between bi-axial and lateral loads. A further complicating effect is the reduced material strength and residual stresses in the heat affected zones (HAZ). Thus, it is still necessary to investigate the ultimate strength of aluminum stiffened panels subjected to combined loads and get a better understanding of the interaction mechanics, which again may lead to improved design rules.

Based on a previously developed numerical model, the structure response of an aluminum multi-span panel subjected to combined longitudinal, transverse, and lateral loads is simulated with the nonlinear finite element method. The welding effects are considered, including both geometrical and mechanical imperfections. By changing the combined load values, the interactions between bi-axial loads are examined. The influences of lateral pressure level on the structure response are also investigated. The failure process, ultimate strength, and stress components between different cases are compared.
Hydroelastic Analysis of Submersible Circular Seaweed Platform
Authors: Nguyen H. P. , Wang C. M. , Tullberg R. , Zhang X. , von Herzen B.
Published: September 2023

This paper presents hydroelastic analysis of a novel submersible circular platform for farming red seaweeds such as Gracilaria dura, Kappahycus alvarezii and Eucheuma. The platform comprises a circular HDPE collar, a system of mooring lines and buoys, and seaweed tube nets. The platform can be submerged during storms to avoid strong surface wave action by filling the collars’ compartments with water and be raised to the surface by injecting compressed air into the collars’ compartments to displace the water. The platform is modelled by using the software AquaSim, where the collar is modelled by using beam elements, and mooring lines are modelled as truss elements. The wave load acting on the platform is estimated by using the Morison equation. Hydroelastic responses of the platform in the floating and submerged modes are investigated. It is found that seaweed tube nets may increase mooring forces significantly and hence the drag forces due to the tube nets cannot be neglected. In addition, by submerging the seaweed platform to an appropriate depth, the deformation of the platform, the von Mises stress and mooring line forces can be reduced considerably as demonstrated herein. Future studies will focus on physical model tests to confirm these findings obtained from numerical simulations.
Dynamic Analysis of an Offshore Fish Farm Integrated With a Floating Offshore Wind Turbine Using Shared Mooring Line
Authors: Ma Yu , Li Lin , Ong Muk Chen , Jin Jingzhe , Su Biao
Published: September 2023

Clean energy captured by offshore wind turbines have been widely used for supporting onshore activities. In the near future, facilities such as offshore wind turbines can also play an important role in energy transition of offshore activities. Offshore wind energy can be employed for electrifying the operations in offshore fish farms, which are traditionally supplied by diesel-engine barges/generators. Based on this motivation, this study focuses on a design of shared mooring system between a semi-submersible offshore fish cage and a spar-type floating wind turbine. A numerical model of the proposed shared-mooring system is implemented in a global response analysis software SIMA for performing fully coupled time domain simulations. The configuration of the shared mooring line is determined using an engineering approach which comprises Irvine’s formulation, system eigenvalue analysis and cost estimation. Moreover, relevant case studies by altering the environmental conditions are performed. Extreme operational conditions that may give large relative motions are investigated thoroughly. The dynamic performance of the integrated system is compared with that of individual structures. The global motion of the floating wind turbine and its mooring line’s tension behavior are obviously influenced by the existence of the shared line. In general, the present work investigates the feasibility of a shared-mooring system for these types of offshore structures and further gives insights about the engineering design procedure.
Viscous Fluid Injections in an Inclined Closed-End Pipe With Applications in the Dump Bailing Method
Authors: Akbari Soheil , Hassanzadeh Hossein , Taghavi Seyed Mohammad
Published: September 2023

The final life stage of a hydrocarbon well is the plug and abandonment (P&A) which aims to prevent the leakage and migration of reservoir fluids towards the upper levels and atmosphere. The P&A operations consist of cement plug placement in the wellbores at the target area. As P&A operations costs constitute a significant proportion of the total decommissioning expenses, precise planning and execution are always required, since a failed P&A job often requires costly and complex remedial operations, and can potentially result in significant environmental costs and financial loss. To fulfill these requirements and reduce the failure risks, the cement plug placement should be run with minimum mixing with the wellbore fluid. The cement slurry is placed in the wellbore using several techniques, among which the dump bailing method is a common and rigless one. In this technique, a relatively small volume of cement slurry is injected into wellbore filled with another fluid held on a bridge plug to remove the in-place fluid. The cement slurry behaves as a high viscosity fluid while the in-place wellbore fluid is mostly water. Motivated by this technique, in this study, the high viscosity fluid injection into an inclined closed-end pipe (representative of well casing) filled with water is studied experimentally. The involved fluids are miscible with constant density difference. The effects of the aspect ratio on the dynamics of high viscosity fluid injection, the fluids mixing, and the quality of the placement flow are analyzed. The results show that the separation of the heavy fluid front from the bulk of the fluid may occur for the larger aspect ratios, while tilting the flow domain towards the vertical direction and increasing the velocity and viscosity of the heavy fluid induce the front separation. Also, for small aspect ratios, the average front velocity increases by the injection velocity while it remains constant approximately in larger aspect ratios. The outcomes of this study can be eventually employed for improving the cement plug placement in the dump bailing method during the P&A of the oil and gas wells.
Open Water Blade Strain Measurements on a Vertical-Axis Tidal Turbine
Authors: Bharath Aidan , Ross Hannah , Nichols Casey , Simms Andrew , Murphy Mark , Raye Robert , O’Byrne Patrick , Monahan Michael , Wosnik Martin
Published: September 2023

Open-water testing of marine renewable energy devices represents a significant milestone and hurdle for research teams and companies that seek to reduce the levelized cost of energy to allow these devices to compete in the open electrical generation market. For open-water testing of tidal energy converters (TECs), accurate measurements of loading characteristics on the blades and other structural components correlated with power performance metrics can be invaluable to further refine design principles and models, allowing continued improvement and cost reductions of new turbine designs. This paper will describe the modifications and additions made to a TEC system to achieve time-correlated blade strain measurements during full turbine operation along with a discussion on the overall impacts the required modifications had on the unmodified turbine.
Challenges of the Digital Transformation for Shipping: Human-Centered Design for Marine Navigation Systems
Authors: Soper Jonathan , Smith Jennifer , Browne Thomas , Veitch Brian
Published: September 2023

The digital transformation of the marine industry presents opportunities and challenges for engineers, designers, and seafarers alike. These challenges are specifically acute in the context of the Arctic, where the presence of sea ice, severe metocean conditions, and limitations to modern charting and navigational aids present increased navigational challenges. Integration and further development of digital bridge tools can improve safety, but must take into account human factors concerns by drawing from literature and case studies where the human-machine interaction has broken down, leading to incidents. In this paper, the challenges of using digital bridge tools to support safe Arctic navigation are discussed as they relate to safe human-machine interaction. A case study of a passenger ship grounding in the Canadian Arctic is presented to demonstrate how failures in bridge equipment design and operation can contribute to accidents. This case study is discussed in relation to literature on human factors engineering and compared to other incidents where human factors was listed as a potential cause. These findings can be used to inform designers of marine navigation systems of the best practices to be aware of when implementing new technologies on the bridge of ships. Additionally, the implications of these findings on autonomous ship development and operation are discussed.
Friction Weakening Mechanism of Sandy Seabed Around a Suction Pile Under Ocean Wave Loading
Authors: Ma Jingyao , Jeng Dong-Sheng
Published: September 2023

Although suction piles have been used for mooring different types of marine facilities, there is still a lack of knowledge on the mechanism of wave-induced soil response around suction piles, In particular, the performance of the interface friction between the wall of the suction bucket foundation and the surrounding soil under ocean wave loading. This study aims to numerically examine the accumulations of excess pore pressures around a suction pile and the weakening mechanism of the interface friction. Based on numerical examples, we found that the effective stresses can be reduced as the excess pore pressure being accumulated around the embedded anchor, which tends to diminish the interface friction between the wall of the suction bucket foundation and the surrounding soil. As a result, the vertical resistance of the suction bucket foundation is decreased. In addition, the pore pressure accumulates significantly on the outside of the suction pile with the larger wave height (H) and wave period (T), but the decreasing permeability (ks) and shear modulus (G) tend to have a weakening effect on the friction of the suction piles.
Ice-Induced Frequency Lock-in Vibration Analysis of Bottom Fixed Wind Turbine Structure
Authors: Yin Haoyang , Wang Bin , Gao Shan , Chuang Zhenju , Qu Yan , Chen Diyi
Published: September 2023

Ice induced vibration is a serious problem for offshore structures in the ice-covered sea area. Especially when ice moves at low speeds against structures, the coupling of the ice crushing failure process and structural vibration will induce lock-in between ice loads and structural vibration. The strong vibration of the structure has been found in the lock-in process and the loading scenario has been named as frequency lock-in (FLI) vibration, which is a dangerous loading condition that needs to be considered in the design. However, no practical analysis method for FLI vibration is available in existing industry standards due to the lack of understanding of the underlying mechanism. To solve this problem, an FLI analysis method is proposed in this paper based on the ductile damage-collapse mechanism for offshore wind turbine structures. The sample study of a 5MW fixed monopile wind turbine shows that the probability of FLI occurrence on an offshore wind turbine is less than that on an oil platform and lighthouses because the wind turbine has a high rise and low-frequency characteristics. The analysis also shows that the magnitude of the FLI vibration is larger than the random vibration caused by continuous brittle ice crushing.
Study on Robust Design for Navigation Dynamics Test for Small Catamaran
Authors: Lin Chun-Cheng , Liang Wei-Li
Published: September 2023

With the trend of science and technology development, unmanned autonomous guidance and navigation requirements are critical. Recently, the advanced worldwide countries have been developing unmanned surface vessels (USVs) as well as possible; they applied these USVs to investigate the marine science, surveillance, transportation, and other civilian fields. Its advantages, including saving human resources, reducing the operation risks, increasing the flexibility and efficiency of mission execution. In this study, application a small catamaran with Global Position System (GPS), Lidar, PID controller and two-thrusters, etc. Through series of experiments and analyses were carried out using Taguchi’s experimental design methods, Taguchi orthogonal array (L9), ANOVA, and obtained the optimal factor-level combination and approached robust design. Based on the previous study results of resistance and payload for the catamaran, this study selected two control factors: the width of the catamaran (factor-A), and thruster positions (factor-B). The study results presented that Taguchi’s optimal configuration design in manual remote mode and waypoint navigation model is A2B1, and the accuracy is also A2B1 in 85% confidence level. The impact of accuracy is analyzed using Taguchi’s experimental design method, which is expected to improve unmanned surface vessels’ tracking and navigation accuracy and be applied by relevant research agencies.
Decommissioning Analyses for Suction Caisson Foundations
Authors: Sharma Lupamudra , Bubel Julian
Published: September 2023

Suction caisson foundations are an economic alternative to piled foundations to support offshore jackets, especially in situations where there is shallow bedrock. Over the last few years significant advances in the design of suction caissons have developed, leading to a strong increase in installed suction caissons, particularly for offshore wind energy. One ecological benefit of this type of foundation is the possibility of a complete removal at the end of its lifetime with today’s technology.

The removal of suction caissons follows a reverse installation procedure. The CPT-based method with site-specific soil resistance factors is preferably calibrated using trial installations. However, the decommissioning needs to also consider the soil’s aging effects and marine growth, which can result in yet unknown additional forces.

This paper presents the methodology of the decommissioning analysis for suction caissons in sandy and layered soils, which was applied to an Offshore Wind Farm in the North Sea. Due to data restrictions, the method is explained using artificially generated CPT logs and synthetic trial installation recordings. The frictional forces are assessed using a simple CPT-approach [1] with back-calculated soil resistance factors from synthetic on-site trials. The aging effects considered are soil type specific with an approach for sand following [2] and for clay based on [3].
Novel Solution for Mitigating Sloshing in Floating Closed-Containment Aquaculture Tanks
Authors: Wiegerink Johannes , Baldock Tom , Callaghan David , Wang Chien Ming
Published: September 2023

Marine aquaculture in floating closed containment tank systems is a promising proposition for the seafood farming industry as it addresses many farming problems associated with open net pens. Current floating closed containment systems typically have a relatively large free surface area and the contained fluid makes up most of the total mass. A major challenge is sloshing of water in the tanks when they are sited at more exposed farming sites. Significant sloshing affects the structural integrity of the containment tank, the day-to-day operation and fish well-being. As fish benefit from a calm and controlled environment with a free surface for air and sunlight, it is necessary to find an engineering solution to mitigate sloshing while live fish are in the tanks. A novel solution developed by University of Queensland (UQ) researchers is to install a slosh suppression block at the top end of the tank. These suppression blocks may be fabricated from HDPE material, and they form an annular slab with its top surface in line with the internal water surface. These suppression blocks contract the free water surface and interfere with resonance by letting sloshing fluid overtop onto them. Experiments were carried out on a floating containment tank model fitted with slosh suppression blocks in UQ’s wave flume. The experimental results demonstrated that appropriately designed slosh suppression blocks can mitigate resonant sloshing and sloshing amplitude. The sloshing flow associated with slosh suppression blocks reduces interference with the main fluid volume where the fish reside to facilitate a calm and controlled environment for fish well-being.
Dynamic Analysis of Launching and Recovering ROV
Authors: Deng Yulin , Ren Xiudi , Nuernberg Martin , Tao Longbin
Published: September 2023

During operation and maintenance of the offshore wind farms, some regular inspections for the wind turbines are performed by remotely operated underwater vehicles (ROV) and service operation vessels (SOV). However, the ROV often experiences excessive motions as it passes through wave zone due to wave-ROV interaction combined with free surface effects. These movements can cause rope slack and sudden loading, which may damage umbilical components and endanger ROV operation.

This study focuses on experimental measurements and numerical prediction of the dynamic tension in the umbilical during launch and recovery of ROV passing through wave zone under different environmental conditions combined with winching process and ship motions. A coupled offshore vessel, umbilical and ROV hydrodynamic analysis for launching and recovering ROV, which is a typical offshore wind farm service operation, is carried out with coupling characteristics being examined.

The numerical results are validated by the 1:10 scale model test measurements on the ROV. The numerical simulation shows ROV experiences larger umbilical tension in recovery process than that in launch process in general. It is found that the tension in the cable is primarily determined by the strength and direction of wind and wave, and the change of winch speed does not significantly impact on the maximum tension in umbilical within the operational range examined.
Impact of Wake Effect on the Levelized Cost of Energy for a Wind Farm Offshore Rio De Janeiro
Authors: Maali Amiri Mojtaba , Osmar de Almeida Jeferson , Bergman-Fonte Clarissa , Shadman Milad , F. Estefen Segen
Published: September 2023

The present paper aims at investigating the impact of the wake effect on the levelized cost of energy (LCOE) of a wind farm located offshore Rio de Janeiro. The study is performed using the reference 15-megawatt (MW) offshore wind turbine of the International Energy Agency (IEA). The wind farm is defined over a square area, where initially 5 × 5 × 15MW wind turbines are placed uniformly over this area. To investigate the impact of the wake effect on the LCOE, the wind farm buildable area is varied systematically from (4 × 3D) × (4 × 3D) to (4 × 15D) × (4 × 15D), where D is the rotor diameter. To perform the wind farm layout optimization, a symmetrical layout optimization algorithm available within the WindFarmer: Analyst software of DNV GL is used. Further, the wake effect is considered by using a simplified CFD-based model. Moreover, the wind data are predicted by Weather Research & Forecasting (WRF) Model at the hub height of the wind turbine. The results show that considering the optimum layout the wake effect is responsible for an increase of about 2% to 30% in the LCOE values for the studied wind farm buildable areas.
Improved Reliability Assessment Methods for Subsea Cables on Rocky Seabed Using NPV Calculation
Authors: McGrath Nicholas , Griffiths Terry , Jorgensen Jack , Pistani Fabrizio , Draper Scott , Cheng Liang
Published: September 2023

To date, the offshore renewables industry has drawn substantially on prior design guidance and recommended practices from the oil and gas industry. This includes the extension of the existing DNV-RP-F109 to cover on-bottom stability of subsea power cables for offshore wind.

However the overwhelming focus of oil and gas design practice is to avoid loss of containment events which represent potentially catastrophic safety, health and environmental consequences. In contrast, the mechanical failure of subsea power cables in an offshore wind farm represents in practice a purely economic consequence. The inherited factors of safety are therefore entirely inappropriate.

A more relevant approach to provide the most reliably cost-effective product is to quantitatively consider the lifetime design risk through an assessment of the relative net present value (NPV) of different options. This allows comparison between increased upfront costs to reduce the probability of component failure versus the future cost of additional maintenance and repair. NPV reliability methods are recommended in ISO 2394 and the new BS10009 Bottom stability of cables on rocky seabeds.

In this paper the NPV of two on-bottom stability risk management strategies are quantitatively compared for subsea cables on rocky seabeds that are being designed to BS10009. Drawing on recent research findings from The University of Western Australia together with published field data, an example cable is analysed to determine that the probability of cable mechanical failure across the design life is around 3.54 × 10−3. This is roughly half an magnitude lower than the limit detailed in IEC 61400-1.

This scenario is compared to the same cable with the addition of filter units (rock bags), which reduces the overall and annual probabilities of failure. The increased upfront cost is compared against the reduced risk of replacing a segment of cable after failure. Based on the low cable probability of failure it is found that, for this worked example, there is no positive NPV benefit to place filter units on the cable from an on-bottom stability perspective.
Empirical Mode Decomposition for Noise Detection and Filtration of Ice-Induced Load Measurements
Authors: Suominen Mikko , BahooToroody Ahmad , Valdez Banda Osiris
Published: September 2023

Structure-ice interaction is a complex process. The related failure process may include intermediate failures of ice, e.g. flacking, that decreases the load level temporarily before larger failures like bending failure occurs. Simultaneously, loads on a frame move and can reach a level of MN. The loads are commonly determined from the structural response with strain gauge measurements where the noise may be few kNs. As the changes in load level related to intermediate failures may be at the same level as noise, it is difficult to separate noise from the measurements.

Empirical Mode Decomposition is a relatively new method in engineering that considers the measurement signal to be composed of a set of functions. The method parses the measurement data into Intrinsic Mode Functions that represent the true data and noise. Removing the modes related to noise enables the use of the method as a filter. This study applies the described filtration technique to the full-scale measurements conducted onboard S.A. Agulhas II in the Baltic Sea. The results demonstrate a good applicability of the method for the filtration of the data that can be applied in the load identification from the measurement data in the future studies.
Numerical Analysis of Ice Blocks Impact on Stiffened Plates According to a Mohr-Coulomb Material and Node Splitting Technique
Authors: Yoon Sungwon , Herrnring Hauke , Müller Franciska , von Bock und Polach Franz
Published: September 2023

Due to the surge of interest and use in Artic, much research has been done over the years on ice-interaction issues. A reliable ice material model is essential to study ice-structure interactions. The ice model in this analysis uses the Mohr-Coulomb mathematical model, which well expresses the behavior of brittle materials. In addition, the ice model was expanded using the node splitting technique to preserve mass and energy, in opposite to the commonly used element erosion technique. In this paper a numerical analysis of a collision between ice blocks with masses of around 100 kg and 600 kg and stiffened steel plates was carried out using the explicit solver LS-DYNA R11.1.0. To validate the simulation, kinetic energy and maximum dent on stiffened steel plates were compared with experimental data performed at the Norwegian University of Science and Technology and the Aalto University. The impact speed is around 4 and 7 m/s, which is frequently observed in ship collisions with ice. As a result of numerical analysis, MCNS ice blocks with particularly high kinetic energy were analyzed to be consistent with the NTNU and Aalto experimental results. In terms of energy balance, it was consistent with previous study in which 20 to 30 % of collision energy was dispersed in the structure. This proves that MCNS ice model can be used to accidental limits scenarios.