Code Comparison Research Articles

General relativistic magnetohydrodynamic simulations with bam: Implementation and code comparison

General relativistic magnetohydrodynamic simulations with bam: Implementation and code comparison

Charged-particle transport in high energy density plasmas

This Special Topic Collection grew out of two gatherings of researchers active in the high energy density (HED) physics community: a mini-conference on charged-particle transport in HED plasma held during the 64th annual meeting of the American Physical Society's Division of Plasma Physics (Spokane, WA, November 2022) and a dedicated charged-particle transport coefficient code comparison workshop (Livermore, CA, July 2023). These gatherings provided opportunities for theoretical, computational, and experimental researchers to discuss the state of the field, including current capabilities and methods, needs of hydrodynamic simulations, and frontiers for future research. This special issue collects a total of 13 research and review articles on charged-particle transport in HED plasmas.

Damage analysis of OC4 jacket subjected to cyclic loading by peridynamic approach

Catastrophic structural failure caused by fatigue damage under cyclic loads can be avoided by identifying critical locations of the damage initiation and the fatigue life during the design stage. Peridynamic (PD) theory defines structure as a collection of material points with non-local bond interactions where the structural discontinuity due to fatigue represented by instantaneous bond breakage is estimated through cumulative decrement of the bond’s life at each load cycle. In this work, we model a reference jacket presented under the Offshore Code Comparison Collaboration Continuation project (OC4) through peridynamic beam formulation. Initially, the static deformations of the beam and deformations of the OC4 jacket under static, harmonic, and irregular point loads are validated with ABAQUS results in all six degrees of freedom. Thereby, the PD fatigue parameters of the jacket’s steel material are calibrated from the experimental data of the corresponding material with a trial simulation for fatigue damage analysis. Later, different load cases from regular waves interacting with the jacket are generated in the PD framework by adopting linear wave theory. Based on the PD cyclic energy release rate model, a comparative study of all load cases to identify critical damage locations with the failure load cycles for damage initiation and fracture is performed for the considered OC4 jacket.

Adjusting to living with chronic liver disease among patients who continue regular healthcare visits for hepatocellular carcinoma surveillance: A grounded theory study.

To explore patients' process of living with chronic liver disease while continuing regular healthcare visits for hepatocellular carcinoma surveillance. Semistructured interviews and participant observations were conducted in this qualitative constructivist grounded theory study. The participants included 11 patients undergoing regular hepatocellular carcinoma surveillance every 1-6 months for 2-30 years. Data were analyzed using coding, memo-writing, theoretical sampling, and constant comparison. The participants incorporated regular healthcare visits into their living cycle. The cycle's core comprised two categories ("inferring my liver condition" and "desiring status quo"). The cycle underwent a transition described by three phases ("seeking ways to live with my chronic liver disease," "being overwhelmed by living with my chronic liver disease," and "reconstructing my life to live with my chronic liver disease"). This transition involved adjusting to living with chronic liver disease while continuing regular healthcare visits. The relative importance of the cycle's core progressively shifted from "inferring my liver condition" to "desiring status quo." This study revealed the transition phases of patients' living cycles in adjusting to living with chronic liver disease while continuing regular healthcare visits. Understanding the different phases in which patients are and the psychological impact of healthcare visits can help them look forward to recuperative actions. Furthermore, patients who have a sense of ownership experience loneliness because of regular healthcare visits. A support system including nurses as part of regular hepatocellular carcinoma surveillance should be established to help ease patients' sense of loneliness by utilizing their sense of ownership.

Numerical treatment of singular ODEs using finite difference and collocation methods

Boundary value problems (BVPs) in ordinary differential equations (ODEs) with singularities arise in numerous mathematical models describing real-life phenomena in natural sciences and engineering. This motivates vivid research activities aiming to characterize the analytical properties of singular problems, to investigate convergence of the standard numerical methods when they are applied to simulate differential equation with singularities, and to provide software for their efficient numerical treatment. There are two well-known, high order numerical methods which we focus on in this paper, the finite difference schemes and the collocation methods. Those methods proved to be dependable and highly accurate in the context of regular differential equations, so the question arises how do they preform for singular problems. While, there is a strong evidence for the collocation schemes to be a robust method to solve singular systems in a stable and efficient way, finite difference schemes are still considered less suitable for this problem class.In this paper, we shall compare the performance of the code HOFiD_bvp based on the high order finite difference schemes and bvpsuite2.0 based on polynomial collocation, when the codes are applied to singular problems in ODEs. We are fully aware of the difficulties in a code comparison, so in this paper, we will try to only diagnose the potential improvements, we could address in the next update of the codes.

Exploring Viscosity Effects in Accretion Disk Simulations: A Code Comparison between FLASH and Athena

This project investigates the impact of viscosity on the evolution of black hole accretion disks through a comparative analysis between FLASH and Athena simulations. Our focus lies in understanding the role of viscosity in overall disk evolution. We present mass accretion rate plots that reveal near identical patterns in disk evolution when varying viscosity. We emphasize the need for additional code-comparison research, including exploration of a wider variety of codes and physics included to enhance our understanding and confidence in simulated models.

Viscous hydrodynamic evolution of neutron star merger accretion disks: A code comparison

Viscous hydrodynamic evolution of neutron star merger accretion disks: A code comparison

Aeroelastic code comparison using the IEA 22MW reference turbine

Reference wind turbine designs and the associated aeroelastic models are widely used in both research and industry. Reference models representing future concepts are of particular interest. Current state of the art aeroelastic tools are relied upon to design the next generation of large wind turbines. However, modelling assumptions may be invalidated by upcoming very large turbines, and different aeroelastic tools may give inconsistent results. A 22MW turbine model has been defined as part of International Energy Agency (IEA) Wind Task 55 on Reference Wind Turbines and Farms to represent future turbines to be deployed in the 2030s. In this study, an aeroelastic model of this turbine has been created in four tools; Bladed, HAWC2, OpenFAST, and QBlade. Code comparisons are presented for steady state operation, linear stability analysis, and time domain power production simulations in steady and turbulent wind. Generally, the codes show a good agreement, but with some differences present in the linear stability analysis, periodic azimuthal variation, and time domain simulations. The models are a good basis for further study with the IEA 22MW turbine, and further code comparison exercises.

LES on wind turbines by comparison of Vortex Particle Method and Finite Volume Method codes

The aim of this paper is to compare two different computational methods that analyse the flow around wind turbine using Large-Eddy-Simulations (LES). The first method uses a three-dimensional unsteady Lagrangian Vortex Particle method (VP) associated to a lifting-line (LL) approach providing radial loads, integrated thrust and power coefficients, circulations and angle of attack across the turbine blades. The second method solves the incompressible Navier-Stokes equations with the classical Finite Volume (FV) method coupled to the Actuator Line (AL) method to model the rotor blades. Both methods are compared by means of a benchmark consisting in a single full-scale NREL5MW wind turbine and the results are thus compared to Martínez-Tossas et al (2018). The comparisons involve loads, angle of attack and velocity along the blade. Wakes downstream of the turbine are analysed via the evolution of flow fields as mean velocity and vorticity. Results are found to be in good agreement with the verification case. A comparison is also performed on the evaluation of the numerical cost, precision and efficiency of both computational methods.

Comparison of Diagnosis Codes to Clinical Notes in Classifying Patients with Diabetic Retinopathy

PurposeElectronic health records (EHR) contain a vast amount of clinical data. Improved, automated classification approaches have the potential to accurately and efficiently identify patient cohorts for research. We evaluated if a rule-based natural language processing (NLP) algorithm using clinical notes performed better for classifying proliferative diabetic retinopathy (PDR) and non-proliferative diabetic retinopathy (NPDR) severity compared to International Classification of Diseases 9th or 10th edition (ICD) codes. DesignCross-sectional study SubjectsDe-identified EHR data from an academic medical center identified 2366 patients aged ≥18 years, with diabetes mellitus, diabetic retinopathy, and available clinical notes. MethodsFrom these 2366 patients, 306 random patients (100 training set, 206 test set) underwent chart review by ophthalmologists to establish the gold standard. ICD codes were extracted from the EHR. The notes algorithm identified positive mention of PDR and NPDR severity from clinical notes. PDR and NPDR severity classification by ICD codes and the notes algorithm were compared to the gold standard. The entire diabetic retinopathy cohort (N=2366) was then classified as having presence (or absence) of PDR using ICD codes and the notes algorithm. Main Outcome MeasuresSensitivity, specificity, positive predictive value (PPV), negative predictive value, F1 score for the notes algorithm compared to ICD codes using a gold standard of chart review. ResultsFor PDR classification of the test set patients, the notes algorithm performed better than ICD codes for all metrics. Specifically, the notes algorithm had significantly higher sensitivity (90.5% [95% CI 85.7, 94.9] vs 68.4% [60.4, 75.3]), but similar PPV (98.0% [95.4-100] vs 94.7% [90.3, 98.3]) respectively. The F1 score was 0.941 [0.910, 0.966] for the notes algorithm compared to 0.794 [0.734, 0.842] for ICD codes. For PDR classification, ICD-10 codes performed better than ICD-9 codes (F1 score 0.836 [0.771, 0.878] vs 0.596 [0.222, 0.692]). For NPDR severity classification, the notes algorithm performed similarly to ICD codes, but performance was limited by small sample size. ConclusionsThe notes algorithm outperformed ICD codes for PDR classification. The findings demonstrate the significant potential of applying a rule-based NLP algorithm to clinical notes to increase the efficiency and accuracy of cohort selection for research.

Computation of transport properties of warm dense matter using Abinit

The dynamics of an inertial confinement fusion capsule, or of a stellar or planet interior, obey a very similar set of equations: magneto-radiative-hydrodynamic equations. The solutions of these equations, however, depend entirely on the transport properties associated with the different materials at play. To properly model the dynamics of these systems, it is necessary to determine with high accuracy the transport coefficients of several materials over a large range of thermodynamic conditions. Experimental capabilities in this respect are still limited due to the nature of the microphysics at play and the extreme conditions involved. Numerical simulations are thus necessary, and in this respect, molecular dynamics simulations based on density functional theory offer exquisite possibilities to constrain the transport properties in the warm to hot dense matter regime. In this paper, we report the methodology used to extract different transport properties based on molecular dynamics performed with the software Abinit. The examples shown are based on the specific cases identified for the purpose of the second charged-particle transport code comparison workshop.

Shear Reinforcement Effectiveness of One-Way Void Slab with the Hollow Core Ratio and Shear Reinforcement

Void slabs offer a promising solution for sustainable construction due to their reduced weight and potential for recycled materials. However, their inherent hollowness can compromise shear capacity compared to solid slabs. This study investigates the effectiveness of shear reinforcement in mitigating this vulnerability. Experimental testing with a four-point support loading confirmed shear failure in all specimens and revealed a significant reserve of shear strength exceeding predictions from ACI 318-14 by at least 1.436. This suggests the potential for more efficient designs that utilize less shear reinforcement while maintaining structural integrity. An inverse relationship between porosity and shear strength was observed, highlighting the importance of considering void content during design. Among established design codes (ACI 318-14, UBC 2, and CEB-FIP 1990), CEB-FIP 1990 provided the most accurate prediction of shear capacity for these reinforced hollow slabs. These findings offer valuable insights for optimizing the shear design of voided slabs. The observed strength reserve suggests the potential for reduced shear reinforcement while maintaining safety. Additionally, the influence of porosity and the code comparison provide crucial considerations for future design practices. This research paves the way for developing efficient and safe voided slab applications, promoting sustainability in the construction industry.

Exploring the experiences of UK-based private physiotherapists when running and progressing a physiotherapy business: a hermeneutic phenomenological study

AimTo explore the experiences of UK-based private physiotherapists when running and progressing a physiotherapy business. DesignA hermeneutic phenomenological approach. ParticipantsSix UK-based private physiotherapy practice owners were recruited via purposive and snowball sampling. MethodsIn-depth, semi-structured video interviews (2 per participant), audio-recorded and transcribed. Field notes, respondent validation and a reflexive diary were used. Data underwent line-by-line analysis, identifying codes and themes. Constant comparison of data, codes and themes occurred throughout. Peer review was utilised, small sections of data and all emerging codes were independently reviewed. ResultsThree interconnecting themes. Working for myself: participants highlighted the freedom, flexibility and independence of business ownership, whilst acknowledging the additional pressures/challenges associated with this. Evolution of a practice: business growth was slow, requiring income supplementation initially. Successful growth often utilised luck and unexpected opportunities. Working with others: participants faced decisions regarding solo or joint ownership, when/what additional staff were required, whether staff should be employed or self-employed, and how to appropriately manage/support staff. ConclusionsPrivate practice ownership brings an array of benefits and challenges. Areas for future research include exploring the stresses of private roles and business ownership, the evolution of private physiotherapy practices, small-scale business partnerships, and employment vs self-employment. Contribution of the Paper•This research suggests that although private practice ownership brings increased freedom, flexibility, and job satisfaction, this is tempered by an array of increased pressures and responsibilities.•Practice growth was gradual, often involving luck and unexpected opportunities.•Clinic owners face challenging decisions regarding the selection, management and support of additional staff.

Review of the second charged-particle transport coefficient code comparison workshop

We report the results of the second charged-particle transport coefficient code comparison workshop, which was held in Livermore, California on 24–27 July 2023. This workshop gathered theoretical, computational, and experimental scientists to assess the state of computational and experimental techniques for understanding charged-particle transport coefficients relevant to high-energy-density plasma science. Data for electronic and ionic transport coefficients, namely, the direct current electrical conductivity, electron thermal conductivity, ion shear viscosity, and ion thermal conductivity were computed and compared for multiple plasma conditions. Additional comparisons were carried out for electron–ion properties such as the electron–ion equilibration time and alpha particle stopping power. Overall, 39 participants submitted calculated results from 18 independent approaches, spanning methods from parameterized semi-empirical models to time-dependent density functional theory. In the cases studied here, we find significant differences—several orders of magnitude—between approaches, particularly at lower temperatures, and smaller differences—roughly a factor of five—among first-principles models. We investigate the origins of these differences through comparisons of underlying predictions of ionic and electronic structure. The results of this workshop help to identify plasma conditions where computationally inexpensive approaches are accurate, where computationally expensive models are required, and where experimental measurements will have high impact.

Nurturing an organizational context that supports team-based primary mental health care: A grounded theory study.

The expansion of the Patient-Centred Medical Home model presents a valuable opportunity to enhance the integration of team-based mental health services in primary care settings, thereby meeting the growing demand for such services. Understanding the organizational context of a Patient-Centred Medical Home is crucial for identifying the facilitators and barriers to integrating mental health care within primary care. The main objective of this paper is to present the findings related to the following research question: "What organizational features shape Family Health Teams' capacity to provide mental health services for depression and anxiety across Ontario, Canada?" Adopting a constructivist grounded theory approach, we conducted interviews with various mental health care providers, and administrators within Ontario's Family Health Teams, in addition to engaging provincial policy informants and community stakeholders. Data analysis involved a team-based approach, including code comparison and labelling, with a dedicated data analysis subcommittee convening monthly to explore coded concepts influencing contextual factors. From the 96 interviews conducted, involving 82 participants, key insights emerged on the organizational contextual features considered vital in facilitating team-based mental health care in primary care settings. Five prominent themes were identified: i) mental health explicit in the organizational vision, ii) leadership driving mental health care, iii) developing a mature and stable team, iv) adequate physical space that facilitates team interaction, and v) electronic medical records to facilitate team communication. This study underscores the often-neglected organizational elements that influence primary care teams' capacity to deliver quality mental health care services. It highlights the significance of strong leadership complemented by effective communication and collaboration within teams to enhance their ability to provide mental health care. Strengthening relationships within primary care teams lies at the core of effective healthcare delivery and should be leveraged to improve the integration of mental health care.

OC6 project Phase IV: validation of numerical models for novel floating offshore wind support structures

Abstract. This paper provides a summary of the work done within Phase IV of the Offshore Code Comparison Collaboration, Continued with Correlation and unCertainty (OC6) project, under International Energy Agency Wind Technology Collaboration Programme Task 30. This phase focused on validating the loading on and motion of a novel floating offshore wind system. Numerical models of a 3.6 MW horizontal-axis wind turbine atop the TetraSpar floating support structure were compared using measurement data from a 1:43-Froude-scale test performed in the University of Maine's Alfond Wind–Wave (W2) Ocean Engineering Laboratory. Participants in the project ran a series of simulations, including system equilibrium, surge offsets, free-decay tests, wind-only conditions, wave-only conditions, and a combination of wind and wave conditions. Validation of the models was performed by comparing the aerodynamic loading, floating support structure motion, tower base loading, mooring line tensions, and keel line tensions. The results show a relatively good estimation of the aerodynamic loading and a reasonable estimation of the platform motion and tower base fore–aft bending moment. However, there is a significant dispersion in the dynamic loading for the upwind mooring line. Very good agreement was observed between most of the numerical models and the experiment for the keel line tensions.

Characterizing natural convection and thermal behavior in a square cavity with curvilinear corners and central circular obstacles

Thermal analysis through natural convection and heated obstacles in a different shape of cavity become an emerging concept among the scientific community. In this framework, this study investigates the natural convection phenomena occurring within a square cavity featuring a non-standard curvilinear shape and internally placed circular obstacles. The analysis focuses on the heat and fluid flow behavior in this unique geometrical configuration, exploring the influence of curvilinear boundaries and obstacles on convective heat transfer. The flow is assumed steady, laminar, and incompressible whereas a magnetic field with strength B0 is applied perpendicular to the fluid flow. No slip conditions are applied on each surface. The curvilinear corners and the inner circular obstacle are kept hot and the others including the bottom, left, right, and top walls are considered at cold temperatures. Numerical simulations are conducted to elucidate the complex interactions between the thermal gradients and fluid motion induced by the presence of circular obstacles. Galerkin finite element method is applied. The code validation and comparison with the existing data are being made. It is demonstrated that the local Nusselt number depends upon Rayleigh numbers, obstruction size, and Hartmann numbers. As the obstacles radius increases from 0.1 to 0.3, the temperature distribution in the middle of the cavity increases by almost 400%. This aids engineering in the manipulation of the heat transfer equipment used in this investigation. Around four corners, the local minimum Nusselt number rises by almost 97% as the radius increases from 0.1 to 0.3. These findings offer insightful knowledge about the fluid's dynamic behavior and a nice understanding of the roles played by geometric features, buoyancy-driven convection, and magnetic effects in the overall dynamics of heat transfer in industrial thermal processes. This knowledge aids scientists in designing suitable heat exchangers based on actual conditions.

Barriers and facilitators of readiness for hospital discharge in patients with myocardial infarction: a qualitative study: quality improvement study.

Readiness for hospital discharge (RHD) in patients with myocardial infarction (MI) is a key concept in the discharge process. This study was conducted to explain the barriers and facilitators of preparation for discharge in patients with MI. A qualitative study was conducted using conventional content analysis from April 2021 to 2022. Data collection was done in a targeted manner through semi-structured interviews until the data saturation stage. Nineteen participants (11 patients, 3 family members, and 5 healthcare team) were interviewed. Data analysis was done in eight steps according to the suggested steps of Graneheim and Lundman. MAXQDA18 software was used for coding. From the interviews, 348 primary codes, 11 sub-categories, and 5 categories were extracted. Finally, after continuous analysis and comparison of interviews, codes, and categories, two themes including "supporting platform" and "caring atmosphere" were extracted, which were the result of the participants' experience and understanding of the barriers and facilitators of RHD. The supporting platform included "family support" and "social support" and the caring atmosphere included "care gaps" and "professional healthcare team performance". The results of this study indicate several factors affecting RHD in heart attack patients. According to the results of the study, the participation of the patient, family, healthcare team, and community in creating RHD is recommended. It is also suggested to pay attention to these factors in care and treatment planning to help improve health and control complications and prevent re-hospitalization in these patients.

Identifying synergies between VLBI and STIX imaging

Context. Reconstructing an image from noisy, sparsely sampled Fourier data is an ill-posed inverse problem that occurs in a variety of subjects within science, including data analysis for Very Long Baseline Interferometry (VLBI) and the Spectrometer/Telescope for Imaging X-rays (STIX) with respect to solar observations. The need for high-resolution, high-fidelity imaging fosters the active development of a range of novel imaging algorithms in a variety of different algorithmic settings. However, despite these ongoing, parallel developments, such synergies remain unexplored. Aims. We study, for the first time, the synergies between the data analysis for the STIX instrument and VLBI. In particular, we compare the methodologies that have been developed in both fields and evaluate their potential. In this way, we identify key trends in the performance of several algorithmic ideas and draw recommendations for the future spending of resources in the study and implementation of novel imaging algorithms. Methods. To this end, we organized a semi-blind imaging challenge with data sets and source structures that are typical for sparse VLBI, specifically in the context of the Event Horizon Telescope (EHT) as well as STIX observations. We used 17 different algorithms from both communities, from six different imaging frameworks, in the challenge, making this work the largest scale code comparison for STIX and VLBI to date. Results. We identified strong synergies between the two communities, as proven by the success of the imaging methods proposed for STIX in imaging VLBI data sets and vice versa. Novel imaging methods outperform the standard CLEAN algorithm significantly in every test case. Improvements over the performance of CLEAN offer deeper updates to the inverse modeling pipeline necessary or, consequently, the possibility to replace inverse modeling with forward modeling. Entropy-based methods and Bayesian methods perform best on STIX data. The more complex imaging algorithms utilizing multiple regularization terms (recently proposed for VLBI) add little to no additional improvements for STIX. However, they do outperform the other methods on EHT data, which correspond to a larger number of angular scales. Conclusions. This work demonstrates the great synergy between the STIX and VLBI imaging efforts and the great potential for common developments. The comparison identifies key trends on the efficacy of specific algorithmic ideas for the VLBI and the STIX setting that may evolve into a roadmap for future developments.

Line Shape Code Comparison of the Effect of Periodic Fields on Hydrogen Lines

Spectral line shapes code in plasmas (SLSPs) code comparison workshops have been organized in the last decade with the aim of comparing the spectra obtained with independently developed analytical and numerical models. Here, we consider the simultaneous effect of a plasma microfield and a periodic electric field on the hydrogen lines Lyman-α, Lyman-β, Balmer-α, and Balmer-β for plasma conditions where the Stark effect usually dominates line broadening.