Predominant Modes Research Articles

Tropical‐wave activity and Madden–Julian oscillation termination

AbstractThe Madden–Julian oscillation (MJO) is the dominant mode of intraseasonal variability in the tropics and generates large‐scale precipitation, cloud, and circulation anomalies. Interactions between the MJO and dry and convectively coupled equatorial waves (CCEWs) have been identified in previous works; however, these studies have not focused on MJO events that maintain themselves versus those that decay. Knowledge on how pre‐existing MJO events interact with CCEWs is important for producing more realistic and reliable representations of MJO events in weather forecast and global climate models. This study presents an analysis of intraseasonally varying outgoing longwave radiation (OLR) and zonal wind anomalies at 200 and 850 hPa from National Oceanic and Atmospheric Administration (NOAA) observations and ERA‐Interim reanalysis data respectively, throughout the lifetime of observed MJO events. A climatology of continuing and terminating MJO events is created from an event identification algorithm using common tracking indices including the OLR‐based MJO Index (OMI), filtered OMI (FMO), real‐time multivariate MJO (RMM), and velocity potential MJO (VPM) index. Wheeler–Kiladis power spectra are calculated for each event type to identify predominant wave modes. Symmetric and anti‐symmetric wave spectra are composited and results include the sensitivity of the variables used to define the waves and index choice for identifying the MJO. Our results show fractional differences between continuing and terminating MJO events that are statistically significant at the 95% level. Statistical significance is most prominent within the MJO band where continuing events have higher power, as well as global mixed Rossby–gravity (MRG) waves and tropical depression (TD) waves where terminating events have higher power. These results are mostly robust to meteorological variable and index although the importance of Kelvin waves is amplified in the VPM. A regional analysis including phase separation contains results that are sensitive to variable and domain although westward traveling waves are commonly associated with MJO termination regardless of location.

DECOLONIAL THINKING AND PRACTICE, TOWARDS SPATIAL TRANSFORMATION IN THE SOUTH AFRICAN BUILT ENVIRONMENT

The paper explores the effects of colonial systems on spatial inclusivity in Global South communities, with a focus on the South African built environment. The aim of the study is to critically review predominant modes of curricula, pedagogy, and practice, to identify possibilities for inclusive approaches towards transformative spatial thinking and practice. The main question guiding the study is, how can an alternative system facilitate inclusion in the spatial transformation of historically marginalised communities? Decoloniality, socio-economic emancipation and pedagogic inclusion define the theoretical framework of the paper. This qualitative study is supported by a phenomenological paradigm. The research methods include a literature review, precedent study, and refers to the South African context as a case study. It must be noted that the paper is written in a decolonial style that draws on the author’s lived experiences in a marginalised South African community. The study proposed an alternate dispensation in the form of a conceptual framework for spatial transformation defined by transformed modes of built environment, thinking and practice facilitated through the formation of an inclusive, critical learning community.

Battery aging mode identification across NMC compositions and designs using machine learning

•A machine-learning framework for aging mode identification in Li-ion batteries •Aging modes are classified using cycle-by-cycle electrochemical features •Battery design, chemistry, and use condition determine predominant aging modes •Understanding aging phenomena creates opportunities for building more robust batteries A comprehensive understanding of lithium-ion battery (LiB) lifespan is the key to designing durable batteries and optimizing use protocols. Although battery lifetime prediction methods are flourishing, diagnosis of the root causes of aging and degradation have not yet been well developed nor studied for a broad mixture of designs and use cases. Here, we create a machine-learning (ML)-based framework that distinguishes aging modes using multiple electrochemical signatures recorded cycle-by-cycle. The predominant aging behaviors include a combination of loss of active materials in cathode (LAMPE) and a loss of Li inventory (LLI) in Li plating or solid electrolyte interphase (SEI) formation, manifested from 44 batteries representing two cathode chemistries, two electrode loadings, and five charging rates. The aging mode classification accuracy is 86% using features within the first 50 cycles and increases to 88% beyond 225 cycles. The same features can quantify the percentage of end-of-life LAMPE with only 4.3% of error. A comprehensive understanding of lithium-ion battery (LiB) lifespan is the key to designing durable batteries and optimizing use protocols. Although battery lifetime prediction methods are flourishing, diagnosis of the root causes of aging and degradation have not yet been well developed nor studied for a broad mixture of designs and use cases. Here, we create a machine-learning (ML)-based framework that distinguishes aging modes using multiple electrochemical signatures recorded cycle-by-cycle. The predominant aging behaviors include a combination of loss of active materials in cathode (LAMPE) and a loss of Li inventory (LLI) in Li plating or solid electrolyte interphase (SEI) formation, manifested from 44 batteries representing two cathode chemistries, two electrode loadings, and five charging rates. The aging mode classification accuracy is 86% using features within the first 50 cycles and increases to 88% beyond 225 cycles. The same features can quantify the percentage of end-of-life LAMPE with only 4.3% of error.

Mean Flow, Turbulent Structures, and SPOD Analysis of Thermal Mixing in a T-Junction with Variation of the Inlet Flow Profile

This paper investigates the effects of different inlet flow profiles on thermal mixing within a T-junction using CFD simulations with the IDDES-SST turbulence model. The different combinations of inlet flow profiles are related to different stage in the flow entry region. The effects of the inlet flow profile on the mean and transient flow behaviour are assessed, while a spectral proper orthogonal decomposition and power spectral density analysis are performed to assess the underlying flow structures and the predominant frequency modes. It is found that the vortical structures associated with the horseshoe and hovering vortex systems consist of a single roll-up vortex for cases with uniformly distributed boundary conditions (BCs) at the branch inlet whereas a double roll-up vortex is observed for the other cases. The double roll-up vortex enhances the mixing locally due to the entrainment of fluid from the branch pipe in these vortical structures, which then results in a lower mean temperature distribution. The appearance of the secondary vortex pair and the nested vortices is delayed for cases with uniformly distributed BCs at the branch inlet, which again results in lower thermal mixing and consequently higher values of mean temperature when compared with the other cases. It is also found that the vorticity related to the counter-rotating vortex pair as well as to the second pair of vortices rotating in the opposite direction is higher for cases with uniformly distributed BCs at the branch inlet. Lastly, the combinations of inlet flow profiles lead to different coherent structures, and the dominant frequencies are of a Strouhal number of around 0.7 for uniformly distributed profiles at the branch inlet and in the range 0.4–0.5 for the other cases.

Blue Zones: Centenarian Modes of Physical Activity: A Scoping Review

AbstractThe primary aim of this scoping review was to identify the predominant modes of physical activity (PA) in each Blue Zone and to explore the influences that environment and culture have on PA. A research team of three Doctor of Physiotherapy students completed a systematic search using five online databases and cross referenced each reviewer in the study selection process. The study selection was based on eligibility criteria comprised of population autonomy/independence, > 80 years, Blue Zone resident, specified mode of physical activity, and utilized all research designs except for case studies and literature reviews. The databases retrieved a total of 236 articles, and 18 of which, met the inclusion criteria. Data synthesis revealed that 81% of the activities engaged by Blue Zone centenarians are moderate intensity activities. Blue Zone centenarians represent a significantly high physical functioning and high levels of activity through labouring occupations, outdoor hobbies and in-home activities. The most predominant mode represented through the included studies was agricultural activities. Overall, Blue Zones Centenarians are highly active, perform continuous and consistent movements daily, maintain daily hobbies, and work beyond the expected age of retirement. The key findings represent a significant effect on PA by environmental and cultural influences of each region.

Bayesian model updating with finite element vs surrogate models: Application to a miter gate structural system

Bayesian finite element (FE) model updating using direct model evaluations of large-scale high-fidelity FE models is extremely computationally expensive. Surrogate models can be used as fast emulators of FE models to accelerate the model calibration process. The physics/mechanics-based FE models are still the underpinning behind the surrogate models. This paper evaluates the loss in accuracy and the gain in computational time while performing Bayesian model updating by using surrogate model evaluations compared to using direct FE model evaluations. This evaluation is crucial before entirely relying on surrogate models in model updating for structural health monitoring (SHM) and damage prognosis (DP) purposes. This paper also demonstrates Bayesian updating and surrogate model construction of large-scale high-fidelity FE models of infrastructure systems. In this regard, the miter gate structural system is considered as the testbed structure. Three predominant damage modes (loss of contact between gate and wall, loss of thickness due to corrosion, and loss of tension in the diagonal rods) are considered for model updating purposes. Bayesian model updating is performed using direct FE evaluations by leveraging parallel computing. Two types of surrogates, namely polynomial chaos expansion (PCE) and Gaussian process regression (GPR), are developed for the miter gate. Model updating is performed again using the trained surrogate models, and the updating results are compared with their counterparts obtained using the direct FE evaluation results. The posterior distribution of the FE model parameters obtained using the trained surrogates are sufficiently accurate with respect to the posterior obtained utilizing the direct FE evaluations. In addition, an approximate 4-fold decrease in the computational time was observed when using surrogate model evaluations instead of direct FE evaluations for model updating.

International crimes through the lens of global constitutionalism

AbstractScholars of global constitutionalism have recently come to examine international criminal law (ICL) and its associated institutions, in particular the International Criminal Court (the ICC). This article prolongs these efforts by pointing to and remedying two deficits of that project with particular emphasis on the Rome Statute crimes. First, how does one account for the role of the international trial in global constitutionalist terms? Second, can global constitutionalism insightfully explain the content and scope of these crimes – that is, both their substantive definition and the predominant modes of liability developed by the ICC? This article answers both questions affirmatively and offers an account of their nexus. It first shows that the Rome Statute crimes are often perpetrated through a hierarchically organized apparatus of control, and interprets their global constitutional significance via the principle of constituent power. It then makes use of Antony Duff’s relational account of criminal liability to offer an account of the international trial. In the international context, one can conceive of the trial as allowing state or state-like authorities to call each other to account, which renders justice to the core function of enabling and limiting political authority on which global constitutionalism centres.

Experiments on cyclic behaviour of cold-formed steel-rubberised concrete semi-rigid moment-resisting connections

This paper presents the results of full-scale physical tests on a recently developed cold-formed steel (CFS) semi-rigid moment-resisting connection infilled with rubberised concrete (RuC) for seismic application. The connection comprises side-plates attached to both sides of built-up tubular CFS beam and column sections through either screwed or welded connections. The tests were performed on both bare steel and CFS-RuC composite connections under cyclic loading for comparison purposes. The predominant modes of failure are beam local buckling and side plate plasticity in the bare steel connections and screw shear failure in the composite connections. The results show that the composite connection typically reaches 45% higher strength and 21% greater energy dissipation capacity than the bare steel connection both having 24 screw arrays. These indicate the beneficial effects of the infill RuC in prevention of the beam local buckling in connections with identical connection configuration. The energy dissipation capacity of the bare steel connection having 36 screw arrays, however, was 70% greater than that of the composite connection with 24 screw arrays. This reflects side plate plasticity being a more effective energy dissipation mechanism than the other identified mechanisms.

Home-delivered meals for people with dementia: Which model delays nursing home placement? - Protocol for a feasibility pilot

BackgroundHome-delivered meals promote food security, socialization, and independence among homebound older adults. However, it is unclear which of the two predominant modes of meal delivery, daily-delivered vs. drop-shipped, frozen meals, promotes community living for homebound older adults with dementia. Our objective is to present the protocol for a pilot multisite, two-arm, pragmatic feasibility trial comparing the effect of two modes of meal delivery on nursing home placement among people with dementia. We include justifications for individual randomization with different consent processes and waivers for specific elements of the trial. Methods236 individuals with dementia on waiting lists at three Meals on Wheels programs' in Florida and Texas will be randomized to receive either: 1) meals delivered multiple times per week by a Meals on Wheels volunteer or paid driver who may socialize with and provide an informal wellness check or 2) frozen meals that are mailed to participants' homes every two weeks. We will evaluate and refine processes for recruitment and randomization; assess adherence to the intervention; identify common themes in participant experience; and test processes for linking participant data with Medicare records and nursing home assessment data. We will conduct exploratory analyses examining time to nursing home placement, the primary outcome for the larger trial. ConclusionThis pilot will inform the follow-on large-scale, definitive pragmatic trial. In addition, the justifications for individual randomization with differing consent procedures for elements of a pragmatic trial provide a model for future trialists looking to develop ethical and feasible pragmatic studies enrolling people with dementia.

RETHINKING RURAL CITIZENSHIP IN COMMODITY REGIONS. LESSONS FROM THE LOS LAGOS REGION, CHILE

Recent literature on commodity frontiers and resource-based economies has reopened the debate surrounding the effects of extractive economies on people’s connection to a political system that sustains predominant modes of production. However, the debate has focused on struggles and broader political tensions between social movements and private companies or the State. The present article adopts a different approach, reflecting on the emergence of distinct forms of citizenship in rural territories. Through examining the salmon industry in the Los Lagos region of Chile, I identify connections between commodity production, place-based identity politics, and citizenship performance. I argue that the concept of rural citizenship understood here as the set of practices of relating to the state grounded in a rural sense of belonging and assessment of the place rural areas have in the frontier project is central to understanding political participation in commodity regions and is informed by the trialectic relationship between place identity, commodity production, and the democratic institutions in place. The article concludes with an invitation for further research into frontier politics from a commodity perspective.

Modelling and analysing failure modes of buried pipelines perpendicularly crossing landslide boundaries

The pipeline response to shallow translational landslides is investigated using semianalytical and numerical methods. The orthogonality of a pipeline and the landslide boundary is considered in this study. In the finite element (FE) analyses, ground movements are simplified as spatially distributed horizontal transverse deformation. The pipe-soil interaction is modelled accounting for large ground deformation, inelastic material behavior, and special contact conditions at the soil–pipe interface. Pipeline failure patterns are summarized based on a series of FE models with varying diameter thickness ratios of the pipe and soil conditions. According to the FE analysis results and the published literature, the existing failure criteria are evaluated and extended to cover new failure modes. The dynamic evolution in the predominant failure modes due to the pipe elongation effects is investigated. A semianalytical solution for the sliding distance to the onset of pipe wall wrinkling is given. In addition, a pipeline failure criterion is proposed based on the relative stiffness. This dimensionless parameter is correlated with failure features, including failure modes, sliding distances to failure initiation, and failure positions. The reliability of the proposed FE model and failure prediction methodology is validated using published results from centrifuge tests and FE analyses. Simple charts for failure prediction in terms of relative stiffness parameters are provided. The proposed approach allows efficient and reliable safety evaluation on X65 steel pipelines subjected to horizontal transverse ground deformation without conducting numerical modelling.

Mechanical behavior of Malan loess under unconfined compression conditions

Loess landslides result in heavy casualties and economic losses. Among them, toppling is one of the predominant failure modes in Malan loess. Loess toppling failure normally arises from deep vertical cracks, which tend to develop in the shoulder areas of loess slopes and extend to a depth of several meters. Under natural conditions, loess’ static lateral pressure coefficient is low and the loess mass within a 2 m horizontal depth from the slope surface approximates an unconfined compression stress state. In this work, we sought to further examine this unconfined compression state using acoustic emission monitoring and in situ computed tomography scans to investigate the mechanical behavior of Malan loess. Results indicated that Malan loess failed under compression-induced tension in unconfined compression condition. It exhibited the brittle failure with an abrupt release of elastic energy. The failure plane was at large angles and occurred nearly along the loading axis. This result coincided well with the vertiloess structure, which is characterized by vertically aligned strong units and weak segments. The above failure mode supports the formation of vertical cracks in the loess strata and consequently the toppling and crack sliding slope failures, as well as the formation of loess walls and columns.

Hybrid and patch anchors for prevention of IC debonding in RC planks flexurally strengthened using FRP

One of the predominant failure modes of reinforced concrete (RC) members strengthened in flexure using fiber reinforced polymers (FRP) is intermediate crack induced (IC) debonding.This failure mode is usually brittle, premature and constitutes a significant underutilisation of the FRP material. To address this type of failure, design guidelines enforce strict limitations on the allowable FRP strain level which can be used in design. In order to suppress IC debonding failure modes, researchers have explored various anchorage systems with varying degrees of success. This paper investigates the use of patch anchors and hybrid anchors to suppress IC debonding failure. An experimental program is presented where RC planks are strengthened with FRP laminates and sheets and anchored using different arrangements. The results show that the addition of two hybrid anchors to the ends of the FRP plate results in significant load and deformation increases compared with unanchored planks.

Experimental Investigation of Cross Laminated Timber Elements with Holes or Notches at In-Plane Beam Loading Conditions

Environmental and urbanisation challenges have encouraged steady growth of mass timber structures where cross laminated timber (CLT) stands out in applications as full-size wall, floor, or beam elements. Beam elements are used mainly in situations where cross layers have a reinforcing effect on the tensile stress perpendicular to the beam axis, such as when introducing holes or notches, which is common practice in beams, due to engineering, installation, or architectural requirements. This paper presents experimental investigations of CLT beams with holes or notches for comparison and validation of an analytical model provided in the literature. Different sizes of holes and notches as well as different placements of the holes were considered in the experiments. All relevant failure modes were analysed and discussed in detail. Two predominant failure modes were indicated, i.e., bending failure and shear failure in crossing areas (mode III). Results further indicate that reduced lamination widths near the hole, notch, or element edges have a relatively small influence on the beam strength. Parametric studies indicate net shear failure (mode II) and tensile failure perpendicular to the beam axis as the critical failure modes in most of the considered cases, indicating their strong underestimation in design verifications according to the analytical model.

Antibiotic resistance genes and their links with bacteria and environmental factors in three predominant freshwater aquaculture modes

Rapid development of aquaculture industry and increasing demand of various inputs (especially antibiotics), are suspected to promote the occurrence and spread of ARGs in aquaculture related environments. However, the occurrences of ARGs under different freshwater aquaculture practices are rarely known. Here, we investigated the seasonal profiles of the main ARGs, intI1 and bacteria in waters from three kinds of predominant freshwater aquaculture practices around the Honghu Lake (China), as well as their co-occurrences and interrelationships with antibiotics, heavy metals and general water quality. The results indicate that quinolone resistance genes (qnrB), tetracycline resistance genes (tetB and tetX) and sulfonamide resistance genes (sul1 and sul2) were the top five predominant ARGs with seasonal variations of abundance. Fish ponds were of the highest absolute abundances of tested ARGs than the other two modes. Crayfish ponds and their adjacent ditches shared similar ARGs profile. Different subtypes of ARGs belonging to the same class of resistance were varied in abundances. Some bacteria were predicted to carry different ARGs, which indicating multi-antibiotic resistances. Moreover, the combined environmental factors (antibiotics, heavy metals and water quality) partially shaped the profiles of ARGs and bacteria composition. Overall, this study provides new comprehensive understanding on the characterization of ARGs contamination in different freshwater aquaculture practices from the perspectives of environmental chemistry, microbiology and ecology. The results would benefit the optimization of aquaculture practices toward environmental integrity and sustainability.

Quasi-static compression performance of material extrusion enabled re-entrant diamond auxetic metamaterial: Fabrication, tuning the geometrical parameters and fibre reinforcements

Auxetics are the class of cellular structures which possess a negative Poisson’s ratio. Negative Poisson’s ratio is achieved through the careful design of the structures. Generally, auxetic structures are not feasible to manufacture using the conventional manufacturing processes due to the unit cell’s complex geometry, additive manufacturing help in alleviating this issue. Material extrusion/Fused Filament Fabrication (FFF) is the most simple, reliable, and low-cost additive manufacturing process in use. The mechanical performance of FFF processed auxetics is influenced by both geometrical parameters of auxetics and printing parameters. The careful selection of these parameters is of prime priority to avoid premature failure of printed structures. In the present work, the re-entrant diamond auxetic mechanical metamaterial is fabricated via FFF using the most commonly used FFF feedstock material, Acrylonitrile Butadiene Styrene (ABS). Initially, efforts are made to fine-tune the FFF process parameters to process these complicated geometrical structures. The ideal deformation parametric zone is defined with preliminary experiments to avoid premature failure of the re-entrant diamond structure. Experimental investigation of the effect of auxetic geometrical parameters and FFF process parameters on the quasi-static in-plane compressive performance is systematically evaluated using the design of experiments. The grey-based optimisation method is considered to optimise influential parameters for combined responses. Further, the re-entrant diamond auxetic metamaterial is reinforced with short carbon and glass fibre, and studied at optimal parametric levels. Reinforcements have enhanced the specific strength and stiffness of the structure with the loss of energy absorption characteristics. Microscopic studies confirm the predominant failure modes as a bond failure for CF-ABS and fibre breakage for GF-ABS. This study also aims to serve as fabrication guidelines to process complicated cellular composite structures via FFF.

Prefiguration and the post-representational politics of anti-deportation activism

ABSTRACT This article addresses a familiar dilemma in discussions of experimental forms of political practice in the context of state racism. On one hand, the predominant modes of engaging with state power through strategically representing claims to state actors often re-affirm the categories of state domination, mimic the hierarchies that radical actors intend to overcome, and tend to become invested in a reformism that limits the horizon of change. On the other, prefigurative politics seeks to craft resistance practices that instantiate desired future relations in ways that can seem hopeless against the institutional power of the state and the investments in racial dominance that underpins its actions, with the danger of producing an unstrategic and naïve inversion of the state logics that activists want to oppose. Drawing on interviews and participation with grassroots anti-deportation activist groups, this article argues that a third concept, that of post-representational politics, is a necessary tool for recognising and engaging with experimental forms of political practice that oppose state racism. It argues that both the practice and the notion of post-representational politics sensitise us to important aspects of radical political praxis in ways that enable responses to critics of prefigurative politics without ever-expanding the boundaries of that concept.

Decomposition of micromotion at the head-neck interface in total hip arthroplasty during walking

Fretting corrosion as one of the leading causes for failure of modular hip prostheses has been associated with micromotion at head-neck taper junction. Decomposition of micromotion is helpful to promote the development of more realistic experiments investigating failure mechanisms of the head-neck junction in total hip arthroplasty. The aim of this study was to decompose the complex three-dimensional micromotion at the head-neck junction into multiple fundamental modes, including three translational and three rotational components. A three-dimensional finite element model composed of head-neck junction, liner and acetabular cup with a typical 12/14 taper size, as well as the taper mismatch of −4', was developed during walking. The analysis was divided into three procedures: a) the assembly simulation of the head and neck during surgery, b) verification with a simplified axisymmetric model, and c) three-dimensional modelling under normal walking. This study revealed that the main forms of micromotion contained circumferential, longitudinal micromotion and longitudinal rolling toggling, and were closely related to the state of motion. The maximum translational micromotion was predicted to be 10.9 μm during the walking gait, with the predominant modes of the circumferential translation of 9.6 μm, the longitudinal translation of 5.5 μm and the longitudinal rotation of 0.29° along the taper junction. These findings may provide design considerations for further experimental testing about fretting and facilitate the understanding of the fretting mechanisms in hip prostheses.

Repairability of aged dimethacrylate-free ORMOCER-based dental composite resins with different surface roughening methods and intermediate materials

Statement of problemThe repair of damaged composite resin restorations has been recommended as a conservative treatment option. However, a reliable protocol for repairing ORMOCER-based restorations is lacking. PurposeThe purpose of this in vitro study was to investigate the effect of different surface roughening methods, repair composite resins, and intermediate materials on the repair bond strength of a dimethacrylate-free ORMOCER-based composite resin. Material and methodsCylindrical composite resin specimens (Admira Fusion) were roughened by using hydrofluoric acid (HF) or a diamond rotary instrument. In both groups, 4 types of intermediate materials were used (Monobond-S, Clearfil SE bond [second bottle], Clearfil Universal bond, GC Composite Primer), and then half of the specimens were repaired with a similar composite resin, and the other half with dimethacrylate composite resin (Clearfil-APX). The specimens (n=20) were then subjected to repair bond strength and failure mode evaluation. The data were analyzed by using the Weibull test, 3-way and 1-way ANOVA, and the Tukey honestly significant difference (HSD) test (α=.05). ResultsAll variables, including the surface roughening method, intermediate material, and repair composite resin, had a significant effect on repair bond strength (P<.001). The lowest repair bond strength values were obtained in the group roughened with HF, prepared with Monobond-S, and repaired with Admira Fusion, and the highest values were obtained in the group roughened with a rotary instrument, prepared with GC Composite Primer, and repaired with Clearfil APX (P<.05). All experimental groups had a lower bond strength than the cohesive and control groups (P<.05). In all experimental groups, the predominant failure modes were adhesive and mixed. ConclusionsThe use of a diamond rotary instrument was a more reliable method of creating roughness, and different intermediate materials based on the clinical situation can be used to repair dimethacrylate-free ORMOCER-based composite resin with similar or different composite resins. However, in general, the highest repair bond strengths were achieved with Clearfil APX-repaired specimens.

Temporal variations of sediment and morphological characteristics at a large confluence accounting for the effects of floodplain submergence

The large confluence between the Yangtze River and the outflow channel of Poyang Lake is receiving attention due to its importance in flood control and ecological protection in the Yangtze River basin. There is a large floodplain along the outflow channel of Poyang Lake, which is submerged during high flow and dry during low flow. The effects of the submergence of this floodplain on sediment and morphological characteristics at this large confluence have not been known. Hence, a field investigation was done in March 2019 (relatively high flow, Survey 3) to complement the previous field studies done in August (high flow, Survey 1) and December 2018 (low flow, Survey 2) to identify the temporal variations of sediment and morphological characteristics considering the submergence of this large floodplain. The predominant sediment transport modes were wash load for Poyang Lake and confluence particles and mixed bedload/suspended load for the Yangtze River particles. The sediment transport processes were largely affected by both the secondary flows and the water density contrast between the tributaries with a lock-exchange sediment rich, denser flow moving across the inclined mixing interface in Surveys 1 and 2. The sediment flux across the mixing interface was weakened in Survey 3 when the density contrast was very small. The stagnation zone near the confluence apex had a low sediment concentration and played a role in preventing the sediment flux exchange between the two flows, and its size, and, thus, its importance as a barrier to sediment mixing were related to the submergence of the floodplain. The bed morphology with the local scour holes at the confluence was largely affected by the large-size helical cells, and this kind of effect was weakened as the secondary flows got restricted in Survey 3. The current results expand the database and knowledge on the sediment transport and morphological features of large river confluences.