bluuebunny/crossref_metadata_2025 huggingface dataset:
Making sense of United States–Brazil relations under Bolsonaro
Authors: Hirst Monica , Valls Pereira Lia B.
Published: October 2022

Political alignment with the United States became an essential aspect of Brazilian foreign policy once Jair Bolsonaro came to power in Brazil. While close ties to Washington had already been established since the interregnum period of the Temer government, far‐right ideological synergies between Bolsonaro and Donald Trump became more highly visible. A common anticommunism stance inter‐linked with antiglobalism reflected commonalities in regional politics and a pronounced strengthening of defense and security ties. Yet, Bolsonaro–Trump common worldviews did not spill over in Brazilian international economics. While political relations with the United States took on major importance, Brazil's investment and trade ties with China were maintained and even expanded. This article focuses on Brazil–United States relations during the Bolsonaro–Trump years. To make sense of this link, two elucidatory paths are drawn—a comparative historical overview that traces previous moments of bilateral ideological synergies to evaluate the exceptional character of Bolsonaro–Trump bilateralism; and contextualization within the process of redistribution of world power intertwined with the rise of China, which has deeply affected the leadership capacity of the United States.
Student teachers as creative writers: does an understanding of creative pedagogies matter?
Authors: Assemakis Kerry
Published: October 2022

Teaching creative writing in primary schools requires an understanding of creative pedagogies that value autonomy and for educators to draw on their own experiences of the creative writing process to support the development of their pupils. This article draws on evidence from 58 undergraduate primary student teachers to further understand how their appreciation of creative pedagogies, combined with their experiences of creative writing, impacts on their approach to the teaching of writing in primary schools. Evidence from questionnaires and interviews reveals that factors such as freedom, choice and focusing on the personal aspects of writing are valued but often because they make writing fun for children, rather than because they develop children's creative behaviours and creative writing. Student teachers' own personal experiences of these factors affect whether they are likely to integrate them into their future practice in school. It is argued that if students experience creative writing that is underpinned by a creative pedagogy within their initial teacher education, they will be better equipped to teach creative writing and prepare children for being writers.
Causal relationships between metabolic‐associated fatty liver disease and iron status: Two‐sample Mendelian randomization
Authors: He He , Liao Shenling , Zeng Yuping , Liang Libo , Chen Jie , Tao Chuanmin
Published: October 2022

Background & Aims

Dysregulated iron homeostasis plays an important role in the hepatic manifestation of metabolic‐associated fatty liver disease (MAFLD). We investigated the causal effects of five iron metabolism markers, regular iron supplementation and MAFLD risk.

Methods

Genetic summary statistics were obtained from open genome‐wide association study databases. Two‐sample bidirectional Mendelian randomization analysis was performed to estimate the causal effect between iron status and MAFLD, including Mendelian randomization inverse‐variance weighted, weighted median methods and Mendelian randomization‐Egger regression. The Mendelian randomization‐PRESSO outlier test, Cochran's Q test and Mendelian randomization‐Egger regression were used to assess outliers, heterogeneity and pleiotropy respectively.

Results

Mendelian randomization inverse‐variance weighted results showed that the genetically predicted per standard deviation increase in liver iron (Data set 2: odds ratio 1.193, 95% confidence interval [CI] 1.074–1.326, p = .001) was associated with an increased MAFLD risk, consistent with the weighted median estimates and Mendelian randomization–Egger regression, although Data set 1 was not significant. Mendelian randomization inverse‐variance weighted analysis showed that genetically predicted MAFLD was significantly associated with increased serum ferritin levels in both datasets (Dataset 1: β = .038, 95% CI = .014 to .062, p = .002; Dataset 2: β = .081, 95% CI = .025 to .136, p = .004), and a similar result was observed with the weighted median methods for Dataset 2 instead of Mendelian randomization‐Egger regression.

Conclusions

This study uncovered genetically predicted causal associations between iron metabolism status and MAFLD. These findings underscore the need for improved guidelines for managing MAFLD risk by emphasizing hepatic iron levels as a risk factor and ferritin levels as a prognostic factor.
Epigenetics and island‐mainland divergence in an insectivorous small mammal
Authors: Cossette Marie‐Laurence , Stewart Donald T. , Haghani Amin , Zoller Joseph A. , Shafer Aaron B. A. , Horvath Steve
Published: October 2022

Geographically isolated populations, specifically island‐mainland counterparts, tend to exhibit phenotypic variation in many species. The so‐called island syndrome occurs when different environmental pressures lead to insular divergence from mainland populations. This phenomenon can be seen in an island population of Nova Scotia masked shrews (Sorex cinereus), which have developed a specialized feeding habit and digestive enzyme compared to their mainland counterparts. Epigenetic modifications, such as DNA methylation (DNAm), can impact phenotypes by altering gene expression without changing the DNA sequence. Here, we used a de novo masked shrew genome assembly and a mammalian methylation array profiling 37 thousand conserved CpGs to investigate morphological and DNA methylation patterns between island and mainland populations. Island shrews were morphologically and epigenetically different than their mainland counterparts, exhibiting a smaller body size. A gene ontology enrichment analyses of differentially methylated CpGs implicated developmental and digestive system related pathways. Based on our shrew epigenetic clock, island shrews might also be aging faster than their mainland counterparts. This study provides novel insight on phenotypic and epigenetic divergence in island‐mainland mammal populations and suggests an underlying role of methylation in island‐mainland divergence.
Site fidelity of common bottlenose dolphins (Tursiops truncatus) in a highly industrialized area of the Galveston Bay estuary
Authors: Mintzer Vanessa J. , Quackenbush Alyssa , Fazioli Kristi L.
Published: October 2022

Coastal common bottlenose dolphins (Tursiops truncatus) that inhabit urban estuaries are exposed to a myriad of anthropogenic threats. To manage and conserve these populations, it is imperative to understand their habitat use and residency patterns. In this study, we evaluated the site fidelity of common bottlenose dolphins in upper Galveston Bay (UGB), a heavily industrialized area of the Galveston Bay estuary. We aimed to identify groups within the population with varying affinity to UGB and to determine if there are resident dolphins in UGB. The Galveston Bay Dolphin Research Program conducted monthly photo‐identification surveys in UGB between January 2016 and December 2019. We identified 442 distinct dolphins within UGB and used their sighting histories to calculate occurrence, permanence, and periodicity. These site fidelity metrics were incorporated into a cluster analysis that revealed three groups. Group 1 (n = 192, 43%) consisted of individuals with the highest site fidelity to UGB and were classified as year‐round or seasonal long‐term residents. Group 2 (n = 141, 32%) were transients and Group 3 (n = 109, 25%) were short‐term users of UGB. This study identified resident dolphins in UGB, and we recommend that this group be monitored closely, as they are particularly vulnerable to stressors in the upper estuary.
Mucormycosis caused by Apophysomyces species: An experience from a tertiary care hospital in Western India and systematic review of global cases
Authors: Samaddar Arghadip , Shrimali Twishi , Sharma Anuradha
Published: October 2022

Apophysomyces species are an emerging cause of mucormycosis in several regions of the world, primarily affecting immunocompetent individuals. The present study addresses the global epidemiology, clinical presentation, management and outcome of mucormycosis caused by Apophysomyces spp. The study included patients diagnosed with Apophysomyces infection at our hospital between March 2019 and August 2020. In addition, cases published in PubMed and Google Scholar from inception to July 2022 were systematically searched and analysed. Only proven and probable cases that meet the eligibility criteria were included. The Indian cases were compared with those from other countries, and the results were analysed by descriptive statistics. In total, six cases of mucormycosis due to Apophysomyces spp. were diagnosed at our hospital, with additional 250 cases identified through literature search. The main underlying diseases were diabetes mellitus (24%), malignancy (3.2%) and chronic kidney disease (2.8%). The major predisposing factor was trauma (55.6%). Necrotizing fasciitis was the most common (63.2%) clinical presentation. Healthcare‐associated mucormycosis accounted for 10.4% of the cases. Globally, A. elegans was the most common species (48.8%), whereas A. variabilis was predominant (86.2%) in India. Surgery was performed in 83.5% of patients. Among those treated with antifungal agents, 98% received amphotericin B and 8.1% received posaconazole. Inappropriate antifungal usage was observed in 12.7%. The overall mortality was 42.3%. A combined medical and surgical management was associated with higher survival. Our study highlights the knowledge gap among physicians regarding this infection. A timely diagnosis and aggressive management can improve the outcomes in such cases.
Platform capitalism and neo‐normative control: “Autonomy” as a digital platform control strategy in neoliberal Chile
Authors: Morales Karol , Stecher Antonio
Published: October 2022

A key element of the platform business model is concentrating great organisational power over the work process while simultaneously allowing workers certain degrees of autonomy and encouraging them to see themselves as self‐employed. This study applied the neo‐normative control concept to analyse the mechanisms platforms use to promote freedom of choice and self‐regulation values, which are formed extra‐organisationally in deeply neoliberal societies such as Chile. The Uber ride‐hailing and Pedidos Ya home delivery platforms in Chile were examined using a labour process theory framework based on an ethnographic design. The results show the specific ways in which these platforms deploy forms of neo‐normative control, how this deployment is anchored in the labour context of neoliberal Chilean society, and how workers re‐signify, stress, or seek to subvert this control strategy. The findings' theoretical and empirical implications are discussed.
Mapping the information landscape of the United Nations Decade on Ecosystem Restoration Strategy
Authors: Meli Paula , Schweizer Daniella , Winowiecki Leigh A. , Chomba Susan , Aynekulu Ermias , Guariguata Manuel R.
Published: October 2022

The strategy of the United Nations Decade on Ecosystem Restoration identifies three pathways for action for overcoming six global barriers thought to hamper upscaling. We evaluated 6,023 peer‐reviewed and gray literature papers published over the last two decades to map the information landscape underlying the barriers and associated pathways for action across world regions, terrestrial ecosystem types, restorative interventions and their outcomes. Overall, the literature addressed more the financial and legislative barriers than the technical and research‐related ones, supporting the view that social, economic and political factors hamper scaling up ecosystem restoration. Latin America, Africa, and North America were the most prominent regions in the literature, yet differed in the number of publications addressing each barrier. An overwhelming number of publications focused on forests (78%), while grasslands (6%), drylands (3%), and mangroves (2%) received less attention. Across the three pathways for action, the action lines on (1) promoting long‐term ecosystem restoration actions and monitoring and (2) education on restoration were the most underrepresented in the literature. In general, restorative interventions assessed rendered positive outcomes except those of a political, legislative or financial nature which reported negative or inconclusive outcomes. Our indicative assessment reveals critical information gaps on barriers, pathways, and types of restorative interventions across world regions, particularly related to specific social issues such as education for ecosystem restoration. Finally, we call for refining “strength of evidence” assessment frameworks that can systematically appraise, synthesize and integrate information on traditional and practitioner knowledge as two essential components for improving decision‐making in ecosystem restoration.
Sedimentology of the Ediacaran barite‐bearing cap dolostone from Gaolan, northern Three Gorges, South China
Authors: Chen Xiaoshuai , Kuang Hongwei , Liu Yongqing , Le Heron Daniel Paul , Wang Yuchong , Bai Huaqing , Peng Nan
Published: October 2022

While Ediacaran cap dolostones research is a hot topic, detailed sedimentological analysis of barite‐bearing cap dolostones remains scarce. Here, new data are presented from Xiangerwan in northern Three Gorges, South China, to illustrate the sedimentary characteristics, depositional environment and formation mechanism of the barite‐bearing cap dolostone. In ascending order, the succession is divided into: (i) pebbly dolostone; (ii) dolostone with unusual sedimentary structures (for example, sheet cracks and tepee structures); and (iii) barite‐bearing facies. The gravels of the pebbly dolostone record the slow relative sea‐level rise during post‐glacial transgression, with a local terrestrial influence. Sheet cracks and tepee structures represent water escape structures in the supratidal and upper intertidal zone, and gently wavy stromatolites in barite‐bearing facies are deposits typical of the upper intertidal zone. In addition, primary radial length‐slow dolomite cements were originally precipitated at the seafloor. In general, the cap dolostone was formed in a shallow‐water ramp environment. The form and sedimentary characteristics of barites indicate a primary (syngenetic) origin and help to divide the barites into bladed (Type I) and needle‐like (Type II) variants. With the ongoing melting of the Marinoan glacier and water density stratification, the cap dolostone was gradually precipitated, accompanied by exotic gravels input. The stratification persisted, and special sedimentary structures were widely developed. Phosphorus and barium ions were brought up from the deep basin by upwelling, indicated by the flourishing stromatolites and barite fan deposition. Above the sediment–water interface, the Type I barite first grew upward from substrates, then the Type II barite could grow either in the reverse ‘V‐shape’ cavities between and within the Type I barite clusters, forming rhythm layers with bedded dolomite, or scattered in the laminae of stromatolites or surrounding dolomite. Finally, the formation of barite fans indicates the end of cap dolostone deposition and deeper water sedimentation.
Grounded Cognition Entails Linguistic Relativity: A Neglected Implication of a Major Semantic Theory
Authors: Kemmerer David
Published: October 2022

According to the popular Grounded Cognition Model (GCM), the sensory and motor features of concepts, including word meanings, are stored directly within neural systems for perception and action. More precisely, the core claim is that these concrete conceptual features reuse some of the same modality‐specific representations that serve to categorize experiences involving the relevant kinds of objects and events. Research in semantic typology, however, has shown that word meanings vary significantly across the roughly 6500 languages in the world. I argue that this crosslinguistic semantic diversity has significant yet previously unrecognized theoretical consequences for the GCM. In particular, to accommodate the typological data, the GCM must assume that the concrete features of word meanings are not merely stored within sensory/motor brain systems, but are represented there in ways that are, to a nontrivial degree, language‐specific. Moreover, it must assume that these conceptual representations are also activated during the nonlinguistic processing of the relevant kinds of objects and events (e.g., during visual perception and action planning); otherwise, they would not really be grounded, which is to say, embedded inside sensory/motor systems. Crucially, however, such activations would constitute what is traditionally called linguistic relativity—that is, the influence of language‐specific semantic structures on other forms of cognition. The overarching aim of this paper is to elaborate this argument more fully and explore its repercussions. To that end, I discuss in greater detail the key aspects of the GCM, the evidence for crosslinguistic semantic diversity, pertinent work on linguistic relativity, the central claim that the GCM entails linguistic relativity, some initial supporting results, and some important limitations and future directions.
Effect of 0.15% sodium hyaluronate on tear film breakup time in healthy anesthetized cats
Authors: Madruga Gabriela Moraes , Ribeiro Alexandre Pinto , Martins Letícia Ramos
Published: October 2022

Objectives

This study aimed to evaluate the effect of 0.15% sodium hyaluronate (SH) on tear film breakup time (TFBT) in healthy anesthetized cats.

Procedures

Forty cats undergoing elective surgery were enrolled. TFBT was assessed before anesthesia to obtain baseline values. As a preanesthetic medication, cats received midazolam, tramadol, and cetamine combined in the same syringe. For anesthetic induction and maintenance, propofol and isoflurane were used. After a 15 min stabilization period to achieve the surgical anesthetic plane, one eye was treated with one drop of SH, while the other eye received saline and served as a control. TFBT was measured at the end of the general anesthesia (T40) and 35 (T75) and 80 min (T120) after the termination of the anesthesia. TFBT values were compared between the control and SH‐treated eyes; both values were also compared with the baseline values (p < .05).

Results

In the control eyes, TFBT significantly decreased from baseline at all time points (p < .001), while in SH‐treated eyes, TFBT significantly increased from baseline only at T40 (p < .0001). In SH‐treated eyes, TFBT was significantly higher than that in the control eyes at all time points (p < .001).

Conclusions

In healthy cats, TFBT decreases significantly after 40 min of general anesthesia, and one drop of 0.15% sodium hyaluronate was able to maintain the stability of the tear film for up to 75 min in treated eyes. However, the isolated effect of each drug used in our anesthetic protocol on TFBT should be executed in further studies.
Q fever screening among pregnant women with pre‐term delivery in northern Israel: An observational study
Authors: Badarni Karawan , Weiner Zeev , Szwarcwort‐Cohen Moran , Zaltzman‐Bershadsky Nelly , Paul Mical , Ghanem‐Zoubi Nesrin
Published: October 2022

The relationship between Q fever, caused by Coxiella burnetii, and obstetrical complications is debatable. Since Q fever is endemic in Israel, we aimed to assess its seroprevalence and clinical characteristics in pre‐term deliveries. Between 1 August 2017 and 31 December 2019, we conducted serological screening for C. burnetii in pregnant women who presented to Rambam Health Care Campus with pre‐term delivery (before 37 weeks of gestation). Anti‐C. burnetii antibodies were tested first by enzyme‐linked immunosorbent assay for the detection of phase I‐IgG, phase II‐IgG and phase II‐IgM. Positive results were confirmed by indirect immunofluorescence with titre determination. Seropositivity was classified into past, acute and chronic infection. Demographic and clinical data of mothers and neonates were collected and compared between seropositive and seronegative women. Out of 386 pregnant women screened for anti‐C. burnetii antibodies, 16 (4.1%) were seropositive, of whom three were diagnosed with past, 12 with acute and one with chronic infection. A higher percentage of seropositive women were immunosuppressed, 2/16 (12.5%) compared with 7/370 (1.9%) in seronegative women, (p = .05). Neonates with small for gestational age were born to 2/16 (12.5%) seropositive women compared with 29/370 (7.8%) to seronegative women, (p = .35). The seroprevalence of Q fever among pregnant women with pre‐term birth reached 4% in northern Israel. This high rate in an endemic setting encourages investigating the role of routine screening for Q fever during pregnancy. Special attention should be given to pregnant immunosuppressed women at risk for exposure to Q fever.
Nitrosylation of cardiac CaMKII at Cys290 mediates mechanical afterload‐induced increases in Ca2+ transient and Ca2+ sparks
Authors: Alim Chidera C. , Ko Christopher Y. , Mira Hernandez Juliana , Shen Erin Y. , Baidar Sonya , Chen‐Izu Ye , Bers Donald M. , Bossuyt Julie
Published: October 2022

Cardiac mechanical afterload induces an intrinsic autoregulatory increase in myocyte Ca2+ dynamics and contractility to enhance contraction (known as the Anrep effect or slow force response). Our prior work has implicated both nitric oxide (NO) produced by NO synthase 1 (NOS1) and calcium/calmodulin‐dependent protein kinase II (CaMKII) activity as required mediators of this form of mechano‐chemo‐transduction. To test whether a single S‐nitrosylation site on CaMKIIδ (Cys290) mediates enhanced sarcoplasmic reticulum Ca2+ leak and afterload‐induced increases in sarcoplasmic reticulum (SR) Ca2+ uptake and release, we created a novel CRISPR‐based CaMKIIδ knock‐in (KI) mouse with a Cys to Ala mutation at C290. These CaMKIIδ‐C290A‐KI mice exhibited normal cardiac morphometry and function, as well as basal myocyte Ca2+ transients (CaTs) and β‐adrenergic responses. However, the NO donor S‐nitrosoglutathione caused an acute increased Ca2+ spark frequency in wild‐type (WT) myocytes that was absent in the CaMKIIδ‐C290A‐KI myocytes. Using our cell‐in‐gel system to exert multiaxial three‐dimensional mechanical afterload on myocytes during contraction, we found that WT myocytes exhibited an afterload‐induced increase in Ca2+ sparks and Ca2+ transient amplitude and rate of decline. These afterload‐induced effects were prevented in both cardiac‐specific CaMKIIδ knockout and point mutant CaMKIIδ‐C290A‐KI myocytes. We conclude that CaMKIIδ activation by S‐nitrosylation at the C290 site is essential in mediating the intrinsic afterload‐induced enhancement of myocyte SR Ca2+ uptake, release and Ca2+ transient amplitude (the Anrep effect). The data also indicate that NOS1 activation is upstream of S‐nitrosylation at C290 of CaMKII, and that this molecular mechano‐chemo‐transduction pathway is beneficial in allowing the heart to increase contractility to limit the reduction in stroke volume when aortic pressure (afterload) is elevated.

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Key points

A novel CRISPR‐based CaMKIIδ knock‐in mouse was created in which kinase activation by S‐nitrosylation at Cys290 (C290A) is prevented.

How afterload affects Ca2+ signalling was measured in cardiac myocytes that were embedded in a hydrogel that imposes a three‐dimensional afterload.

This mechanical afterload induced an increase in Ca2+ transient amplitude and decay in wild‐type myocytes, but not in cardiac‐specific CaMKIIδ knockout or C290A knock‐in myocytes.

The CaMKIIδ‐C290 S‐nitrosylation site is essential for the afterload‐induced enhancement of Ca2+ transient amplitude and Ca2+ sparks.
Joint Optimization of Maintenance and Spare Parts Inventory for Multi-Unit Systems With a Generalized Structure
Authors: Yan Tao , Lei Yaguo , Li Naipeng , Pintelon Liliane , Dewil Reginald
Published: October 2022

Joint optimization of maintenance operations and spare parts inventory is promising for ensuring the reliable and efficient operation of industrial systems. Extensive studies have been conducted on joint optimization emphasizing various aspects. However, those studies still suffer two limitations. (1) The considered system structures are restricted to particular cases, and thus are unable to fully address the joint optimization needs of actual industrial systems possessing various structures, and (2) imperfect maintenance, as has been commonly adopted in industries, is not addressed in existing works, which compromises the economic efficiency of the joint policy. Targeted at these limitations, this paper investigates the joint optimization for multi-unit systems with a generalized structure, i.e., the systems consist of multiple identical units, and each unit possesses a complex subsystem structure. First, a total cost rate model is formulated, in which maintenance actions include both perfect replacement and imperfect maintenance, and the spare parts inventory policy consists of an (s, S) policy and the option to place emergency orders. Based on the formulated model, a simulation optimization method is proposed. The simulation module evaluates the total cost rate iteratively, and the optimization module utilizes a variable neighborhood search-based algorithm to obtain a high-quality joint policy with tractable computation times. Two numerical examples are provided for demonstration, and sensitivity analyses are conducted to study the effects of parameters.
Pareto Optimal and Dual-Objective Geometric and Structural Design of an Underwater Kite for Closed-Loop Flight Performance
Authors: Naik Kartik , Beknalkar Sumedh , Reed James , Mazzoleni Andre , Fathy Hosam , Vermillion Chris
Published: October 2022

This paper presents the formulation and results for a control-aware optimization of the combined geometric and structural design of an energy-harvesting underwater kite. Because kite-based energy-harvesting systems, both airborne and underwater, possess strong coupling between closed-loop flight control, geometric design, and structural design, consideration of all three facets of the design within a single codesign framework is highly desirable. However, while prior literature has addressed one or two attributes of the design at a time, this work constitutes the first comprehensive effort aimed at addressing all three. In particular, focusing on the goals of power maximization and mass minimization, we present a codesign formulation that fuses a geometric optimization tool, structural optimization tool, and closed-loop flight efficiency map. The resulting integrated codesign tool is used to address two mathematical optimization formulations that exhibit subtle differences: a Pareto optimal formulation and a dual-objective formulation that focuses on a weighted power-to-mass ratio as the techno-economic metric of merit. Based on the resulting geometric and structural designs, using a mediumfidelity closed-loop simulation tool, the proposed formulation is shown to achieve more than three times the powerto-mass ratio of a previously published, unoptimized benchmark design.
Experimental Study on Dynamic Characteristics of Fluid-Conveying Pipe for OTEC
Authors: Hisamatsu Ryoya , Adiputra Ristiyanto , Utsunomiya Tomoaki
Published: October 2022

A commercial-scale Ocean Thermal Energy Conversion (OTEC) floating plant will be attached a large diameter Cold Water Pipe (CWP). There are concerns about unstable vibration and changes in the dynamic characteristic due to too large mass flow rate. Since the vibration may interfere development of larger capacity plant, comprehending the phenomena have generated considerable interest. The main objective of this study is to confirm whether the theory that describes the vibration of submerged fluid-conveying pipe reproduces the real phenomena through a tank experiment. We construct the experiment eliminated possible disturbances, and the free damping vibration of polycarbonate pipe of 4 m length is measured during water intake. In order to compare the experimental pipe and theoretical models, the damping characteristics are identified from the results without internal flow. As a result of the comparison, although the theoretical model using the inlet end condition reproduces basically reproduced the experiment, we observe a three dimensional nonlinear behavior that could not be predicted by the theory. We believe that this experiment will serve to improve the theories.
Modelling of a Subsea Shuttle Tanker Hovering in Ocean Currents
Authors: Ma Yucong , Xing Yihan , Silva Marina Simplicio Da , Sui Dan
Published: October 2022

A baseline design of subsea shuttle tanker (SST) for liquid carbon dioxide transportation was recently proposed by authors to support studies evaluating the ultra-efficient underwater cargo submarine concept. One important topic is the position keeping ability of SST during the offloading process. When the subsea shuttle tanker is offloading at the storage site, it hovers above the well in the vicinity and connects with the wellhead using a flowline. The entire offloading process takes around four hours. Ocean currents can cause tremendous drag forces on the subsea shuttle tanker during this period. Preliminary studies show that the drag force introduced by the sideways current is over 80 times that of the heading current. Therefore, the SST would current-vane to reduce load effects from currents and maintain its position. During this process, the flow velocities over hydroplanes are low, and the generated lift forces are generally insufficient to maintain the SST’s depth. In the baseline design, compensation tanks are used to maintain the depth when hovering. However, the ballasting and de-ballasting of tanks are generally slow. It is, therefore, envisioned that although it can compensate for the weight change, additional thrusters that can provide actuation with higher frequencies are still required. This paper presents a planar model to study the SST’s vertical position keeping ability in current using its propeller and tunnel thrusters. The ocean current follows a first-order Gauss-Markov process. SST motions are first measured by a Luenberger observer and then delivered to a Linear Quadratic Regulator to calculate the control input. This work facilitates the SST station keeping problem and helps with the design of SST control units. Effects from controller gains and observer gains on the SST motions are discussed. Numerical results show that the designed hovering control system can ensure the SST’s stationary during offloading. Finally, the SST footprints at 0.5 m/s, 1.0 m/s, and 1.5 m/s mean current speed are presented.
Estimation of Still-Water Bending Moment of Ship Hull Girder Using Beam Finite Element Model and Ensemble Kalman Filter
Authors: Tatsumi Akira , Iijima Kazuhiro , Fujikubo Masahiko
Published: October 2022

Longitudinal bending strength is the most fundamental strength of ship hull girders, and longitudinal bending moment acting on hull girders should be accurately monitored to ensure structural safety during ship operations. The longitudinal bending moment classified into still-water bending moment and wave-induced bending moment. This study proposes a data assimilation method to estimate the still water bending moment, and especially focuses on inverse estimation of cargo load. In the proposed method, hull-girder response in still water is simulated by a beam finite element model supported by distributed restoring springs. Nonlinearity of restoring force due to change of hull shape under waterline is considered in the simulation. To assimilate simulation by beam FEM with observed strains, ensemble Kalman filter is implemented in the beam FEM. To validate the proposed data assimilation method, a still-water tank test using a backbone-type hydro-elastically scaled model is conducted. The proposed method is applied to the measured data, and the ballast load is inversely estimated from the bending strains. The estimation accuracy of the ballast load is improved as repeating prediction by beam FEM and filtering by ensemble Kalman filter, and estimated ballast load has good agreement with actual.
Long-Term Mechanical Properties of Barrier Materials for Cementing Operations – Analysis of Morphology and Micro-Structure
Authors: Kamali Mohammadreza , Khalifeh Mahmoud , Saasen Arild , Silva Santos Moreira Paulo Henrique
Published: October 2022

In the oil and gas and geothermal industry, a barrier material is pumped behind the casing to fill the annular gap between the casing and formation/outer casing. After placement, this slurry is solidified rapidly, and it functions to seal the annular space and protects the casing during the lifecycle of the well. In this article, four different barrier materials namely expansive cement, non-cement pozzolan-based material, geopolymer, and thermosetting resin are examined under equal conditions.

The long-term mechanical properties of the candidate materials were tested by measuring uniaxial compressive strength (UCS), tensile strength, and Young’s modulus. These properties were measured at seven different time intervals, from one day to nine months after curing at a bottomhole static temperature of 90 °C and pressure of 170 bars. The change in the mechanical properties was further investigated by using scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) techniques. The results were benchmarked with the properties of the API neat class G cement as non-commercial reference material.

Our results show that the neat class G cement had a consistent behavior in most of the test period, and its UCS was dropped by 23 % after nine months compared to six months. The expansive cement had no significant change in mechanical properties, but the expansive crystal can weaken the structure, especially close to the boundaries with the cement matrix. The pozzolanic material and geopolymer did not develop early strength. The pozzolanic material reached a plateau after seven days, while the geopolymer developed strength up to six months. The thermosetting resin had the highest UCS and tensile strength up to one month, but its mechanical properties were started to deteriorate from seven days after curing.
Dynamic Response of a Generic Self-Elevating Unit in Operation With Hull in Water
Authors: Zhang Chi , Santo Harrif , Cai Minbo , Magee Allan
Published: October 2022

Self-elevating units (SEUs), with a water-tight hull fitted with long support legs and spudcans, are widely used in offshore drilling and operations, as well as offshore wind turbine installations. SEUs are also known as jack-up rigs. A jack-up rig undergoes several stages of operations involving different leg configurations, such as legs retracted, legs suspended in the water, spudcans pre-loaded into the soil, and legs deployed in the seabed with the hull lifted clear above water. The hull and the legs will therefore be subjected to various external environmental actions. Transit operation (when the hull is in water) is only carried out in mild environmental conditions, due to safety concerns. The dynamic response of the SEU in the transit operation is less investigated in contrast to normal operation when the hull is in elevated condition supported by the legs.

In this paper, we investigate the dynamic behavior of a generic (in-house designed) three-legged SEU. The configuration is such that the hull is in the water while the spudcans are secured in the seabed. A nonlinear time-domain model is established for the coupled hull and legs through Cummins’s equation. The hull is assumed as a rigid body with motions in six degrees of freedom, and the hydrodynamic coefficients are calculated from radiation and diffraction analysis. The legs are simplified as lumped mass models with equivalent stiffness value as the prototype, and Morison-type hydrodynamic loads are applied. Various scenarios of boundary conditions are considered, i.e., constant spudcan constraint stiffness, pin, fixed boundary conditions, and incidental cases when up to two spudcans are released while the other is still secured in the seabed. The dynamic responses of the SEU under operating sea conditions are examined. The results are compared to those from the conventional quasi-static analysis where the legs are simplified as linear springs.

It is found that the dynamic response of the SEU with the hull-in-water condition can be as large as that in the elevated condition, despite the much milder sea conditions. The operational limit can be significantly reduced if the resonant motion occurs. These results show the importance of a full coupled dynamic analysis for a rational design of an SEU and may serve to guide operations for mobile offshore drilling units. It is even more crucial for certain SEUs where the hulls are intended to be in the water for a longer period, such as offshore wind turbine installation vessels. It may also allow the transit operations to be performed under slightly more severe conditions by better defining safe operational limits and reducing uncertainty.
Numerical Simulation of Local Scour Around Square Artificial Reef
Authors: Yang Mingda , Tang Yanli , Zhao Fenfang , Xu Shiji , Fang Guangjie
Published: October 2022

Artificial reefs (ARs) are one of the key man-made constructs to restore the offshore fishery resources and recover the ecological environment. However, it is found that many ARs lost their stability and function due to scour. In order to ensure the functional effect of ARs, it is of great significance to study the instability of ARs, like burying caused by scour in different flow conditions. The three-dimensional numerical model established by FLOW-3D is used to study the local scour characteristics around the AR in steady currents. The RANS equations, closed with the RNG k-ε turbulence model, are established for simulating a stable flow field around one AR. The simulation results are compared with previous experimental results and shows good agreement. Then, the effect of the opening number and the incident angles of ARs on the scour characteristics, the equilibrium scour depth and maximum scour volume are investigated. The results indicate that the scour depth and scour volume decrease with the increasing opening number. Moreover, the empirical equations of the effect of the opening number of the AR on the equilibrium scour depth and maximum scour volume are proposed based on the numerical results. The change of the incident angles will affect the change of bed shear stress at the most upstream corner of the AR. The greater bed shear stress results in a more intense scour. This study will provide theoretical support, and practical guidance for the optimized engineering design and construction of ARs.
Analysis of the Experimental Data of Slamming Loads on an LNG Carrier in Abnormal Waves
Authors: Wang Shan , Guedes Soares C.
Published: October 2022

The objective of the paper is to identify slamming characteristics of ships in abnormal waves by analysing the experimental slamming loads for an LNG carrier from the model tests of the ship, which were conducted at the Ocean Engineering Division of the Technical University Berlin at a model scale of 1:70. To validate the experiments, the numerical results from a time domain nonlinear strip theory code are compared with the measurement of the ship motions and vertical bending moment amidships of the LNG carrier in the New Year Wave. The time series of the slamming pressures on different locations (on the bow and stern) obtained in the experiments are analysed and discussed by studying the peaks using the analytical distribution models, namely, Weibull distribution, Generalized Extreme Value distribution and the Gumbel distribution. The extreme values of the pressure peaks obtained using the three distribution models are compared. Discussion is also provided for the results with two different Froude numbers in order to check the effects of the ship speed on the phenomenon.
Random Experimental Uncertainty Analysis on the Model Tests of an LNG Carrier in Extreme Seas
Authors: Wang Shan , Guedes Soares C.
Published: October 2022

The present work aims at assessing the random experimental uncertainties in the response behaviour of an LNG carrier on the model tests that were carried out at the Ocean Engineering Division of the Technical University Berlin at a model scale of 1:70 within the EU project EXTREME SEAS. The response metrics of interest include the heave and pitch motions, vertical bending moments and slamming pressures on the hull. An irregular sea state with a significate wave height of 11.5m and a peak period of 12 s described by JONSWAP spectrum is considered. Based on the times series of the experimental measurements, the peak values of the heave and pitch motions, vertical bending moments and slamming pressures are identified. The extreme value, the average value of the largest 1/10, the average of the largest 1/3 and the mean value of the peaks are calculated. Then the random standard uncertainties on these parameters are calculated as the standard deviation of the metric across the 5 repeated tests, divided by the square root of the number of observations. The uncertainties for different parameters are calculated and compared for two forward speeds of the ship in head waves.
On Common Research Needs for the Next Generation of Floating Support Structures
Authors: Aksnes Vegard , Alsos Hagbart , Bachynski-Polić Erin , Berthelsen Petter Andreas , Delhaye Virgile , Furevik Birgitte R. , Jostad Hans Petter , Kristiansen Trygve , Ommani Babak
Published: October 2022

The world is facing several industrial and societal challenges, such as providing enough renewable energy and enough safe and healthy food as formulated in the United Nations sustainable development goals. Using floating stationary structures, the ocean can contribute to solving several of the challenges. New applications need new types of structures, with which we have limited experience. These support structures will be diverse, but also have essential research needs in common.

Design of novel floating structures need reliable descriptions of the marine environment. This is particularly challenging for semi-sheltered coastal regions, with complex topography and bathymetry. Novel structures are likely to be compliant, modular and/or multi-body, requiring increased understanding and rational models for wave-structure interaction. Structures with sustainable, safe, and cost-efficient use of materials, including untraditional ones, must be developed. Smart, affordable, and reliable mooring systems and anchors for novel applications are necessary for station keeping. Digital solutions connecting the various stages of design and operation, as well as various design disciplines, researchers, and innovators, will be necessary. Sustainability will be an integral part of any new design.

To unlock the potential of novel floating structures, we need to understand the requirements of the applications, as well as the associated technology gaps and knowledge and research needs. This paper highlights research needs for innovation within floating offshore wind, floating solar power plants, novel aquaculture structures, and coastal infrastructure.
Time Domain Prediction of VIV Responses in Oscillatory Flow Conditions
Authors: Wu Jie , Yin Decao , Jin Jingzhe , Lie Halvor , Passano Elizabeth , Sævik Svein , Grytøyr Guttorm , Tognarelli Michael A. , Karunakaran Daniel , Andersen Torgrim , Igland Ragnar
Published: October 2022

Vortex induced vibrations (VIV) may be developed in the sag-bend area of steel catenary risers (SCRs) and lazy wave risers (SLWRs) induced by the top motions. There is lack of reliable tools to predict VIV responses in such oscillatory flow conditions in the riser design. A time-domain VIV load model has been implemented in software VIVANA-TD. This load model adds a vortex shedding force term with a synchronization model to the conventional Morison load formulation. The synchronization model introduces a phase-coupling between the force and response, which effectively captures how the local vortex shedding frequency may increase or decrease to obtain lock-in. This time domain VIV load model makes it possible to account for time-varying flow speed.

In the present study, the vortex shedding process and response characteristics of VIV in oscillatory flow conditions have been reviewed. The capability and limitations of the existing time domain VIV load model have been investigated. The empirical parameters have been derived from model test data. The validation study using the Equinor SCR and Deepstar SLWR test data shows that the predicted maximum fatigue damage is within a factor of 5 compared to the measurement for 85% of the cases. This demonstrates that the present VIVANA-TD can describe the main characteristic of VIV responses in the oscillatory flow conditions.
On the Feasibility of Large-Scale Resonant Fatigue Testing to Study Bolt Force Relaxation
Authors: Van Wittenberghe Jeroen , Vanden Haute Cedric , Shirzadeh Rasoul , Thibaux Philippe
Published: October 2022

Offshore wind towers are generally connected with the foundations by a bolted joint. Bolt preload relaxation and loosening result in regular inspections and maintenance. This project describes results of both static and dynamic bolt relaxation tests on a large-scale bolted flanged joint. The tests are carried out on a resonant bending fatigue test setup. These tests serve as a feasibility study to demonstrate this testing method is suitable for efficiently studying the bolt behaviour. The bolts are preloaded up to 90% of their yield stress. Static relaxation between 5 and 28% of yield stress was measured over a period of 20 days. The dynamic testing is spread over 6 days with a total of 1.5 million cycles resulting in a maximum relaxation of 7% of yield. The dynamic test program consists of loading blocks with different amplitudes and intermittent pause periods. Additionally, the Schmidt-Neuper relation between tube shell stress and bolt force is experimentally investigated during the dynamic tests. Initially, the measured bolt forces are lower than predictions by the Schmidt-Neuper relation. However, bolt forces increased significantly after an overload test.
Theoretical and Experimental Analysis on Low-Cycle Fatigue Crack Initiation for High Strength Steel Stiffened Plates
Authors: Lei Jiankang , Yue Jingxia , Xu Zhiting , Fang Xuan , Liu Hongrui
Published: October 2022

The ship hull is generally subjected to asymmetric cyclic loads under various and complex oceanic environments. Especially, under extreme sea conditions, the loads suffered by ship structures conform to the characters of low-cycle fatigue loads. Consequently, the large-scale plastic yield may occur at the locations of stress concentration part of the ship structure due to structural discontinuity or initial defects and result in low-cycle fatigue damage. However, the commonly used methods for low-cycle fatigue life prediction do not premeditate the influence of large range of yield and asymmetric load. Therefore, the effect of mean stress on the crack initiation life of the stiffened plate, the basic unit of ship structure, is investigated in this paper. The crack initiation experiments of welded stiffened plates under different stress amplitudes and stress ratios were carried out. Moreover, the modified Neuber rule considering the large-scale plastic yield and several strain-life models considering the influence of mean stress were used to estimate the life under experimental loading conditions respectively. Different life results were predicted by various strain-life models and compared with the results of experiments. The comparison shows that the modified Neuber rule can accurately describe the local stress-strain at the root of notch in the state of large-scale plastic yield than the Neuber rule, and the Walker model is the most recommended to predict the low cycle fatigue crack initiation life.