bluuebunny/crossref_metadata_2025 huggingface dataset:
Prediction of the minimum heat loss coefficient for safe operation of a Li-ion cell: A machine learning approach
Authors: Akula Rajesh , Kumar Lalit
Published: June 2024

The operating conditions, either C-rate or DoD, of all the Li-ion cells in the battery pack of EVs are subject to continuous change. In addition, the cells’ ambient temperature (Tamb
) is also not constant due to geographical or day/night conditions. As the generation and transfer of heat from the cells are vital functions of C-rate, DoD, and Tamb
, choosing an appropriate heat loss coefficient for the given conditions is imperative to maintain the operating temperature of the cell below a specified Set Point Temperature (SPT). The selected heat loss coefficient must be the minimum possible such that overcooling of the cells can also be eliminated. The present study employed a machine learning based surrogate model called Gaussian Process Regression (GPR) to achieve this objective for an AMP20M1HD - A0 Li-ion pouch cell. The training and validation of the surrogate model are conducted with the samples generated using Latin Hypercube Sampling and simulated using the NTGK model available in the Ansys Fluent. The model’s accuracy is further tested for three new combinations of the operating conditions, which are not used for training or validation. Using the present model, the predicted minimum heat loss coefficient successfully regulates the cell’s maximum temperature below a user-specified SPT for the same user-given operating conditions. The developed model immensely helps in designing a cost-effective battery thermal management system with optimum cooling capacity by predicting the nature of heat loss coefficients for all plausible combinations of the operating conditions.
Condensation of water on PDMS-coated copper surfaces for fresh water harvesting
Authors: Pfeiffer T , Kappl M , Butt H-J , Stephan P , Gambaryan-Roisman T
Published: June 2024

With an increased need to solve fresh water scarcity for humanity in many places around the world, dew water harvesting is one promising approach to improve the situation. While condensation from humid air has been a research topic for many years, it is still unclear how surface wettability influences the condensation efficiency and the fresh water harvest. In this work, we contribute to bridging this knowledge gap by comparing the condensation efficiency of PDMS-coated hydrophobic and uncoated hydrophilic surfaces. We characterize the humid air velocity field to enable comparability of the present results on condensation efficiency with the results gained at other conditions. In addition, the surface wetting behavior prior to and after the condensation experiment is investigated to analyze the PDMS-coating longevity and allow to draw conclusions on their suitability for long term use in condensation applications.
Confined boiling on an immersed heated corner: influence of one wall on the other
Authors: Volpe Antonio Della , Baudin Nicolas , Roux Stéphane , Yu Robert , Fiard Jean-Michel , Bellettre Jérôme
Published: June 2024

An experimental test section with horizontal and vertical heated plates forming an inverted L-shape is filled with 3M Novec7000 dielectric fluid at atmospheric pressure. Both plates of 64 × 40 mm
2 dimensions are heated with wall heat fluxes ranging from 0 to 20 W cm
−2. There is natural convection for low heat fluxes, medium heat fluxes trigger boiling and for higher power, the critical heat flux is reached. The wall temperature and heat flux are calculated from in-wall thermocouple measurements in steady state. The bubbly flow on the vertical surface is observed with a high-speed camera through a window.

The confinement between the vertical heated surface and the wall is varied from 0.5 to 15 mm. In the range of this study, the heat transfer coefficient in natural convection and nucleate boiling regimes increases when the spacing decreases. However, since the critical heat flux decreases when it is more confined, the film boiling regime is reached faster. From the visualizations and the thermal measurements we try to model these different behaviors.

Depending on which plate is switched on or off we observed different behaviors. The confinement of the vertical plate does not have any influence on the horizontal one since the plate width is much bigger than the gap change. Also, the horizontal plate heating does not influence the heat transfer on the vertical plate in this study. However, there is an influence of the vertical boiling on the horizontal one, stronger when there is a confinement than in free configuration.
Nucleation, growth and bubble detachment in liquid-vapor phase change on structured surfaces
Authors: Arhar Klara , Može Matic , Zupančič Matevž , Golobič Iztok
Published: June 2024

Comprehensive grasp of heat and mass transfer, particularly in applications involving liquid-vapor phase change, hinges on management of nucleation, growth, and detachment of vapor bubbles. Various parameters influence the dynamics of phase-change heat and mass transfer and thus dictate the interactions between the surface, the liquid, and the vapor, profoundly impacting the underlying processes. To tailor these phenomena and harness them for technical applications involving high heat flux densities and intense mass transfer, such as boiling and electrolysis, surface functionalization is under intense development. By designing structured surfaces and creating preferential nucleation sites that promote heterogeneous nucleation, it is possible to exert control over the location and density of active nucleation sites on the surface. This, in turn, enables the regulation of bubble growth and detachment from the surface. With the aim of identifying optimal surface treatments for functionalizing surfaces and enhancing their performance in phase-change applications, we evaluated the nucleation, growth and detachment of a single bubble in a liquid-vapor phase change on untextured and laser-textured surfaces during water electrolysis. Platinum was chosen as the preferential material due to its favourable electrochemical properties for the hydrogen evolution reaction in acidic media. Electrolysis was performed at various voltages and the bubble dynamics were evaluated through high-speed imaging to investigate the intricacies of bubble growth and their mutual interactions. At 3.5 V using the laser textured surface, hydrogen bubbles detaching from the electrode surface had on average 40% smaller diameter, while the frequency of their detachment was 2,5-times higher compared to the untextured surface. This opens the possibility for further research that could lead to improving the efficiency of electrolysis.
The effective use of focused shadowgraphy for single bubble nucleate pool boiling investigations
Authors: Everts M , Welzl M , Brüggemann D
Published: June 2024

Nucleate pool boiling is known for its high heat transfer coefficients. Despite being widely implemented, the prediction of nucleate pool boiling mechanisms remains complex and single bubble heat transfer analysis is helpful to simplify the problem. Owing to the interesting bubble behaviour during nucleate pool boiling, publications tend to focus on the bubble dynamics while the experimental setup is only briefly discussed. Small but critical information on the experimental setup is often omitted, which makes it challenging or even impossible to reproduce or compare experimental data. Therefore, the purpose of this study is to provide a systematic approach to using focused shadowgraphy for the investigation of single bubble dynamics using R245fa. A pool boiling experimental setup has been built and equipped with temperature, pressure and heat flux sensors, as well as a high-speed camera and light source. The nucleate pool boiling takes place at a single cavity on a copper block. The influences of the heat transfer surface area, light source, and diffuser films were investigated to provide a systematic approach to the use of focused shadowgraphy for the investigation of single bubble dynamics.
Application of the localized method of fundamental solutions to heat transfer problems
Authors: Gáspár Csaba
Published: June 2024

A localized version of the Method of Fundamental Solutions is applied to the 2D steady heat transfer equation with spatially varying thermal conductivity. Though the corresponding fundamental solution cannot be computed in general, the localization splits the original problem into several subproblems defined on small subdomains; in these subdomains, the subproblems are approximately converted to certain convection-diffusion equations with constant coefficients, so that the Method of Fundamental Solutions is applicable. In each subdomain, the corresponding subproblem is solved separately. This results in an iterative method, which mimics the overlapping (alternating) Schwarz method. Due to its advantageous numerical properties, the technique seems a useful generalization of the Method of Fundamental Solutions. The method is illustrated through numerical examples.
A superconvergence result in the RBF-FD method
Authors: Kolar-Požun Andrej , Jančič Mitja , Kosec Gregor
Published: June 2024

Radial Basis Function-generated Finite Differences (RBF-FD) is a meshless method that can be used to numerically solve partial differential equations. The solution procedure consists of two steps. First, the differential operator is discretised on given scattered nodes and afterwards, a global sparse matrix is assembled and inverted to obtain an approximate solution. Focusing on Polyharmonic Splines as our Radial Basis Functions (RBFs) of choice, appropriately augmented with monomials, it is well known that the truncation error of the differential operator approximation is determined by the degree of monomial augmentation. Naively, one might think that the solution error will have the same order of convergence. We present a superconvergence result that shows otherwise - for some augmentation degrees, order of convergence is higher than expected.
On different implementations of boundary conditions in the meshless RBF-FD method for phase-field modelling of dendritic solidification
Authors: Dobravec T , Mavrič B , Šarler B
Published: June 2024

Dendritic morphology is one of the most common microstructures in solidifying metallic materials. The phase-field method represents one of the most suitable approaches for modelling the evolution of dendritic morphology. In this paper, the meshless RBF-FD method and forward Euler scheme are used to solve the partial differential equations arising from the phase-field model for dendritic growth. We consider the growth of a single dendrite into a supercooled pure melt. On the computational domain’s surfaces, we apply symmetric boundary conditions. Special care has to be taken in the RBF-FD method to satisfy boundary conditions accurately. In this paper, we test four different implementations of boundary conditions. In the first one, the boundary conditions are incorporated when constructing an interpolation problem in local support domains containing boundary nodes. In the second one, the interpolation problem in the local support domains does not consider boundary conditions, which are satisfied by solving a system of linear equations for values in all boundary nodes at each time step. The third one complements the second one with the use of ghost nodes. The fourth implementation is an alternative one, where the values in ghost nodes are determined by direct mirroring. The accuracy and computational efficiency of all four implementations are compared. We discuss the advantages and disadvantages of each implementation. We show that using ghost nodes is recommended for implementing Neumann boundary conditions in the RBF-FD method.
Stratified liquid-liquid flow through microchannels with grooved walls
Authors: Dewangan Mainendra Kumar , Persoons Tim
Published: June 2024

Patterned surfaces have numerous applications in the microscale flow regime, such as heat transfer enhancement, mixing, and microfluidics devices. The present study analytically examines the pressure-driven flow of two immiscible Newtonian fluids through a grooved microchannel. The orientation of the channel is defined as the top and bottom walls being flat and wavy surfaces, respectively. A no-slip boundary condition is assumed at both walls. The present problem is investigated by invoking the Fourier theory for a flow along streamwise grooves at the Stokes flow limit. Flow rates and velocities of both fluids are determined analytically and numerically. A finite-element-based numerical study is conducted to understand the accuracy of the theoretical models. Results are generated to show the effects of viscosity ratio, wall undulation amplitude and wavelength of the patterned channel. For both fluids with a small wavelength, hydraulic permeability decreases with increasing the pattern amplitude at various viscosity ratios. Meanwhile, in the case of large wavelengths, hydraulic permeability increases with pattern amplitude at different values of viscosity ratio. This behaviour of permeability is identified for fluid 2 (which is in contact with the grooved surface). Roughness and confinement effects are captured with increasing pattern amplitude at different wavelengths and viscosity ratios. The present analytical model agrees well with numerical values. The findings provide a deeper understanding of the stratified flow through microchannels with undulating surfaces, with potential applications in electronic cooling, skin-friction drag, interfacial fluid dynamics, and enhancement and reduction of heat transfer.
Enhancing the degrees of freedom of topology optimization via variable-porosity metal foams: Design of heat conduction paths in a volume-to-point problem
Authors: Bianco N , Fragnito A , Iasiello M , Mauro G M
Published: June 2024

Multi-material topology optimization determines the optimal distribution of different materials within a design domain in order to achieve specific performance goals. This work takes advantage of such technique to enhance the thermal performance of a benchmark heat conduction problem. The aim is to investigate the impact of enhancing the degrees of freedom introducing different materials, i.e., variable-porosity metal foams in addition to the high-conductivity solid, in the design of heat conduction paths under a constant weight constraint. The study leverages a well-established case study – volume-to-point problem – in the field of thermal management, ensuring a consistent basis for comparison. It consists of a square domain with a uniform heat source and a Dirichlet condition at a point on the boundary. Interpolation functions – ordered solid isotropic material with penalization (SIMP) type – allow the properties – in this case thermal conductivity – of materials to be correctly assigned. The distinction between materials is made by means of different thresholds on the projection function. By varying the foam porosity, we investigate the trade-offs between weight and heat dissipation efficiency. The objective is to find the ideal combination of materials that maximizes heat transfer – minimizing the average domain temperature – while conforming to weight constraints. Findings reveal that multi-material topology optimization – when applied to heat conduction problems – can outperform other design approaches, such as the growth-based algorithm, the evolved constructal tree, and the classical topology optimization (with one solid material), thereby paving the ground to innovative heat sink designs in weight-constrained environments.
Numerical investigation of gyroid heat exchanger
Authors: Jena Bhagaban , Choudhari Vipul D , Saravana Kumar G , Arul Prakash K
Published: June 2024

A novel cylindrical gyroid surface-based tube is designed to investigate fluid flow and heat transfer characteristics numerically. The simulations are carried out using finite volume based CFD software Ansys Fluent. The numerical validation is performed to verify the robustness of the solver and grid independence study are also carried out to compute the simulations using optimum mesh. The heat exchanger (HX) tubes with gyroid surfaces are manufactured using additive manufacturing and a crossflow HX is fabricated with a bank of gyroid tubes where the experiments were conducted. The numerical results of the Realizable k-ε turbulence model with enhanced wall treatment is validated with in-house experimental data. The thermal performance of the gyroid tube HX is also compared with a conventional circular tube (CCT). Parametric analysis is also carried out by varying the gyroid design parameter and an optimum HX design is proposed. The results show that due to larger surface area and enhanced fluid mixing, the gyroid tube-based HXs show better thermal performance compared to CCT-based HX.
Forced air flow through a rectangular channel with 3D turbulence enhancers: fluid-dynamics and thermal analysis by Large Eddy Simulations
Authors: Corti M , Vitali L , Gramazio P , Fustinoni D , Niro A
Published: June 2024

Many newer engineering applications, like the cooling of automotive batteries and high-performance CPUs, require heat exchangers (HEs) with large contact areas and very small heights. Performances of this type of HEs can be significantly improved by using surfaces enhanced with optimized 3D structures. The project Mood4hex aims at designing new geometries with optimized morphology, starting from a large database of experimental data on ribbed surfaces. In order to perform an optimization algorithm on such surfaces, analyses are carried out on CFD models with increasing complexity and computational time, to find a fast-running code that preserves the physical meaning. Until recently we used RANS models, and now we began to investigate the use of Large Eddy Simulations (LES) as a higher order validation tool for simpler models. In this paper, we present the results of LES along with experimental data of a forced air flow inside a streamwise periodic rectangular channel of high aspect ratio, i.e., 1:10, equipped with standard transverse ribs (α = 90°). More specifically, the ribs are placed only on the lower wall that is operated at constant heat flux, while air flowing at Re 500 or 1000. Comparison of experimental data vs LES results shows weaknesses and strengths of the model.
A combined experimental and numerical approach for heat transfer enhancement in a minichannel using half rectified pulsating flows
Authors: Kumavat P S , Alimohammadi S , O’Shaughnessy S M
Published: June 2024

The miniaturization of electronic packages and their associated high-power density circuits requires more innovative cooling solutions. Single phase pulsating flows offer a promising solution due to their disruption of the thermal boundary layer. This study aims to bridge the knowledge gap by using experimental and computational methods to investigate the complex flow characteristics of laminar pulsating flows in a heated rectangular minichannel and couple that analysis with an investigation of thermal-hydraulic performance. Experimental analysis involves a uniformly heated thin foil approximating a constant heat flux bottom wall. Wall temperature measurements are recorded using an infrared thermography system. Analogous to the experimental conditions, a three-dimensional conjugate heat transfer computational model is developed with a volumetric heat generation source. Positive and negative half rectified sinusoidal pulsating flow waveforms are studied for dimensionless pulsation frequencies or Womersley numbers of Wo = 2.5 and 5.1 at a fixed flow rate amplitude A
0 = 3. For the positive half rectified waveform, a marginal enhancement in heat transfer of 2.2% for Wo = 2.5, A
0 = 3 was obtained. Whereas the negative half rectified case leads to a heat transfer enhancement of 9% and 6% for Wo = 2.5 and Wo = 5.1 respectively, with a high thermal performance of η = 2.4 over corresponding steady flow.
Blood flow in deforming vessels
Authors: Białecki R , Adamczyk W , Borys D , Głowacki J , Gracka M. , Melka B , Psiuk-Maksymowicz K , Ostrowski Z , Rojczyk M , Wasilewski J
Published: June 2024

Blood flow is most often modeled in vessels whose shape does not change over time. This approach significantly simplifies the calculations and reduces their time. Temporal vascular deformations affect blood flow patterns, the deposition of atherosclerotic plaques, the formation of aneurysms, and many other phenomena. There are two methods to consider blood vessel deformations: registration of vascular geometry by diagnostic imaging such as CT, MRI, ultrasound or the use of the fluid-structure interaction (FSI) models. The first method requires additional procedures for processing image data, and the second requires knowledge of the material properties of the vessel walls, which is a very challenging task for in vivo experiments. The article will show the method to obtain a time-varying geometry of the coronary artery based on images obtained by angioCT. Emerging difficulties arise from the use of images of different resolutions and the need to generate numerical grids of the same topology at every time step. This problem was solved by using image segmentation, smoothing the resulting 3D geometry, and projecting the numerical grid on subsequent shapes of the vessel using diffeomorphism. The simulations have been validated using measurements on a phantom. The resulting velocity fields show the locations of intense oscillations of the shear stress of the wall where the atherosclerotic plaque is deposited.
On some computational aspects for electromagnetic-thermal dosimetry of mm waves
Authors: Cvetkovic Mario , Dodig Hrvoje , Poljak Dragan
Published: June 2024

This work is on the use of a state-of-the-art hybrid boundary element method/finite element method (BEM/FEM) for electromagnetic (EM) dosimetry and the coupled thermal dosimetry model based on the Pennes’ heat transfer equation (PHE) for biological tissue solved by means of FEM. The distribution of the induced electric field obtained in both homogeneous and non-homogeneous human head models using EM model is used as a distributed heat source in the piecewise homogeneous human head thermal dosimetry model. As the penetration depth is inversely proportional to the frequency of incident EM wave, we consider the heating depth in several human head models, to illuminate whether homogeneous models in the EM part of the model are pertinent in the thermal dosimetry part. If confirmed, the results could be found useful in standardisation efforts related to the assessment of human exposure to EM fields in the high frequency range.
Long-distance settling simulation of equiaxed dendrite by a moving-frame algorithm: phase-field lattice Boltzmann study with parallel-GPU AMR
Authors: Sakane S , Takaki T
Published: June 2024

In large-ingot castings, the settling of equiaxed dendrites often results in distinct cone-shaped negative segregation in the lower region of the ingot. To accurately predict and control such macrosegregation, it is important to understand the kinetic behavior of equiaxed dendrites in the melt. The phase-field lattice Boltzmann (PF-LB) model is powerful for simulating dendrite growth with melt convection and solid motion. However, it is computationally expensive and represents only the short-distance motion of dendrites in three-dimensional (3D) simulations. For an efficient 3D evaluation of the effect of dendrite motion and rotation on growth behavior, we introduce the moving frame algorithm to PF-LB simulations. Here, the computational domain tracks the settling dendrite to express long-distance settling without restricting the domain size. The PF-LB simulations were accelerated by parallel computing using a combination of multiple GPUs and adaptive mesh refinement (AMR), also referred to as parallel GPU-AMR. The moving-frame algorithm was modified to adapt to AMR. From the simulation results, we demonstrate that the proposed method helps evaluate the effect of dendrite rotation on the settling and growth velocities of equiaxed dendrites in 3D.
Mixed convection by buoyancy and magnetothermal forces
Authors: Kaneda M , Yoshimura S , Suga K
Published: June 2024

The magnetic force in the paramagnetic fluid depends on the local gradient of magnetic flux density and the temperature-dependent magnetic susceptibility. In the presence of the gravity, the buoyant force due to the temperature difference additionally overlaps, and the resultant flow becomes a mixed convection. In this study, the effect of the temperature-dependent magnetic force (magnetothermal force) on the natural convection was numerically investigated. The magnetic field formed by the permanent-magnet array was employed and effective one was discussed in terms of the heat transfer. A three-dimensional Rayleigh-Benard convection simulation was conducted with the magnet array below the bottom hot wall. It was found that the magnetothermal force enhances the convection not only where the magnet locates but also away from the magnet due to the force profile.
Water adsorption on microporous chabazites as thermal energy storage materials
Authors: Ristić A , Mal S , Zabukovec Logar N
Published: June 2024

Thermochemical energy storage can reduce fossil fuel consumption, which is still dominant in heating of buildings. The efficiency of the sorption technology is determined by the performance of the adsorbent, which should have a high water adsorption capacity and, consequently, a high energy storage density, stability under humid conditions, and fast kinetics of adsorption and desorption. In this study we investigated the effect of different elemental compositions of the commercial and laboratory prepared microporous aluminophosphates, natural and synthetic zeolites with chabazite structure and their modifications in powder and granular form on water adsorption capacity. The highest water uptake among the aluminophosphates was found for APO-34-IL, which was prepared by green synthesis with the low cost ionic liquid, while the highest water uptake of all the samples analysed was found for the composites of the natural zeolite with CaCl2.
Mercury stocks in discontinuous permafrost and their mobilization by river migration in the Yukon River Basin
Authors: Smith M Isabel , Ke Yutian , Geyman Emily C , Reahl Jocelyn N , Douglas Madison M , Seelen Emily A , Magyar John S , Dunne Kieran B J , Mutter Edda A , Fischer Woodward W , Lamb Michael P , West A Joshua
Published: June 2024

Rapid warming in the Arctic threatens to destabilize mercury (Hg) deposits contained within soils in permafrost regions. Yet current estimates of the amount of Hg in permafrost vary by ∼4 times. Moreover, how Hg will be released to the environment as permafrost thaws remains poorly known, despite threats to water quality, human health, and the environment. Here we present new measurements of total mercury (THg) contents in discontinuous permafrost in the Yukon River Basin in Alaska. We collected riverbank and floodplain sediments from exposed banks and bars near the villages of Huslia and Beaver. Median THg contents were 49+13/−21 ng THg g sediment−1 and 39+16/−18 ng THg g sediment−1 for Huslia and Beaver, respectively (uncertainties as 15th and 85th percentiles). Corresponding THg:organic carbon ratios were 5.4+2.0/−2.4 Gg THg Pg C−1 and 4.2 +2.4/−2.9 Gg THg Pg C−1. To constrain floodplain THg stocks, we combined measured THg contents with floodplain stratigraphy. Trends of THg increasing with smaller sediment size and calculated stocks in the upper 1 m and 3 m are similar to those suggested for this region by prior pan-Arctic studies. We combined THg stocks and river migration rates derived from remote sensing to estimate particulate THg erosional and depositional fluxes as river channels migrate across the floodplain. Results show similar fluxes within uncertainty into the river from erosion at both sites (95+12/−47 kg THg yr−1 and 26+154/−13 kg THg yr−1 at Huslia and Beaver, respectively), but different fluxes out of the river via deposition in aggrading bars (60+40/−29 kg THg yr−1 and 10+5.3/−1.7 kg THg yr−1). Thus, a significant amount of THg is liberated from permafrost during bank erosion, while a variable but generally lesser portion is subsequently redeposited by migrating rivers.
Improving dynamical-statistical subseasonal precipitation forecasts using deep learning: A case study in Southwest China
Authors: Nie Yanbo , Sun Jianqi
Published: June 2024

Subseasonal precipitation forecasting is challenging but critical for water management, energy supply, and disaster prevention. To improve regional subseasonal precipitation prediction, previous studies have proposed a dynamical-statistical projection model (DSPM). In this study, we develop a new method that combines the DSPM and deep learning (DL), called the DL-DSPM. The DSPM is developed using the observed relationships between large-scale atmospheric circulations and regional precipitation, and the dynamical forecasted atmospheric circulations from the European Centre for Medium-Range Weather Forecasts (ECMWF) model. The DL-DSPM improves upon the DSPM by correcting biases in atmospheric circulation forecasts from the ECMWF model using two DL models, namely, residual network and U-Net models. In the case of Southwest China (SWC), DL models can improve atmospheric circulation forecasts at lead times beyond 5 pentads, including large-scale drivers of SWC precipitation variability. The DL-DSPM outperforms the ECMWF model and DSPM forecasts in predicting precipitation anomalies beyond 4 and 5 pentads over most SWC regions, respectively. In addition, the DL-DSPM is more skillful than the ECMWF model and DSPM in predicting extreme precipitation events more than 4 pentads in advance. The successful combination of DL and the DSPM provides a new possible direction for DL applications in subseasonal precipitation forecasting.
Large-scale vortex formation in three-dimensional rotating Rayleigh-Bénard convection
Authors: Sasaki Hirofumi , Takehiro Shin-ichi , Yamada Michio
Published: June 2024

Numerical experiments are performed on three-dimensional thermal convection between parallel plates in a rotating system with a larger horizontal region than in previous studies. It is confirmed that a large-scale vortex (LSV) with positive vorticity (cyclonic) is formed over a significant part of the region and its horizontal size increases if the horizontal region is extended. The correlation analysis in the vertical direction shows that the small-scale motion has a typical structure of the baroclinic vortex of thermal convection in the rotating system, whereas the large-scale motion is a barotropic vortex that is not associated with thermal convection. A horizontal spectral analysis of the individual terms in the kinetic energy equation reveals that the nonlinear effect of the small-scale vortex motion caused by the buoyancy force induces a large-scale toroidal component, and that the LSV is maintained by the balance between the nonlinear effect and the viscous dissipation of the large-scale motion. The results of this analysis indicate the importance of kinetic energy damping mechanism for the appearance of LSVs. When weak damping operates at larger scales, it is expected that the maximum extent of the vortex appears even if the horizontal region is extended further. On the other hand, the emergence of LSVs will be prevented when strong enough damping is effective at larger scales.
Follow Your Bliss and Other Lies about Calling
Authors: Miller-McLemore Bonnie J
Published: June 2024

This book challenges superficial ways people use the word calling, providing a revolutionary way to approach it, not as some glorified word but as a complicated, ambiguous, and even painful reality. Shallow renderings of calling in trendy self-help literature and religious circles (“follow your bliss”; “God has a plan for your life”) greatly diminish the power of the word and are not only inadequate but sorely misleading, especially given the complexity of life and the reality that callings always demand a great deal from people. Lofty expectations that a person can (or must) find the perfectly fitting job, the one and only special life partner, the ideally balanced life, or the one-time summons from God are deceptive and destructive. Calling means so much more than seeking gladness, job success, or God’s will. To truly grapple with calling requires consideration of how it evolves amid the constraints of life. Drawing on stories from memoirs, novels, cultural figures, and everyday people, the book looks at six difficulties in early, middle, and late adulthood, from leaving paths untrodden (missed callings) and running into impediments (blocked callings) to having competing callings (conflicted callings) and failing in one or more area (fractured callings) to managing unwanted demands (unexpected callings) and giving up what one has done and loved (relinquished callings). By insisting that callings have benefits and burdens across adult life, the book hopes to make the idea of calling more useful and real for all those who aspire to live meaningful, purposeful lives.
Unexpected Callings: With Great Power Comes Lots of Work
Authors: Miller-McLemore Bonnie J
Published: June 2024

This chapter returns to the beginning—the road not taken—but with the unexpected twist of time or aging and detritus or the accumulated baggage of life. As people age, they amass obligations. Callings mean, by definition, mounting entanglements. To agree to this job or to love this or that person means suddenly bearing unexpected duties. Unexpected callings can also emerge at any time of life, however, when duties arise within callings that they didn’t anticipate but must assume, often imposed from outside themselves. The chapter explores what it means to assume unexpected callings, discerning not just desire or talent but the need for service. It considers how to maintain the fine balance between self-care and appropriate sacrifice or sacrifices that are chosen and motivated by love, not forced, that rest on communal support and grace, and that require practice over time.
From Failure to Action
Authors: Sbisà Marina
Published: June 2024

This chapter deals with some main features of Austin’s philosophy of action that emerge from the papers he wrote in the late 1950s. It remarks that Austin’s approach to action is ‘negative’ in the sense that it is based on the examination of cases in which the agent does not really perform an action: distinct kinds of failures may reveal distinct components or ‘stages’ of the agent’s performance. It also discusses Austin’s idea that not all action verbs admit of any possible kind of adverbial modification in standard circumstances. It comments on Austin’s analysis of pretending (as a case of not really doing something), arguing that it is revealing of the plurality of trends of activity that may be present in one and the same stretch of behaviour. It concludes that Austin’s conception of action is responsibility-based and that the ascription of an action is an attribution of responsibility for a certain state of affairs to an agent. It adds some considerations about Austin’s remarks about the roles of responsibility and freedom as regards action.
Further Aspects and Implications of Austin’s View of Action
Authors: Sbisà Marina
Published: June 2024

This chapter completes the overview of Austin’s philosophy of action. It considers intention, which Austin takes to be a cognitive state of awareness of what we are up to that accompanies our behaviour, and its relation with attributions of responsibility. It explores what kind of an ontology of action is implicit in Austin’s philosophy and what kinds of components of an action Austin identifies as its ‘stages’ and ‘phases’. It discusses the implications of Austin’s view of action for the so-called ‘accordion effect’, concluding that he is open to action pluralism: when a stretch of behaviour gives rise to more than one effect, we do not need to establish which is the only real action, but for each effect we can identify which is brought about thanks to that stretch of behaviour, we can say that the agent performed the corresponding action. Finally, it summarizes the features of Austin’s philosophy of action expounded and discussed so far.
Meaning
Authors: Sbisà Marina
Published: June 2024

This chapter explores Austin’s views on meaning. It focuses on the notions of sense and reference and how he deals with them in the context of his works on truth, assertion, and speech acts. It examines how, in his view, sense is related to types of things or situations and discusses an ambiguity in his use of the notion of reference as regards the distinction between reference of words to items and reference of assertions to situations. It discusses the notions of descriptive and demonstrative conventions that Austin employs in the analysis of truth, arguing that the connections established by demonstrative conventions are unmediated by descriptive contents. It examines what place can be given to reference within the speech act, highlighting the central role of what Austin calls ‘point of utterance‘ as regards both illocutionary force and the interpretation of referential devices. Finally, it illustrates how Situation Semantics has taken inspiration from Austin’s views on truth and reference.
The Impact of a Digital Contraceptive Decision Aid on User Outcomes: Results of an Experimental, Clinical Trial
Authors: Espinosa Matthew , Butler Stephen A , Mengelkoch Summer , Prieto Laura Joigneau , Russell Emma , Ramshaw Chris , Rose-Reneau Zak , Remondino Molly , Nahavandi Shardi , Hill Sarah E
Published: June 2024

Background

Nearly 40% of unplanned pregnancies in the USA are the result of inconsistent or incorrect contraceptive use. Finding ways to increase women’s comfort and satisfaction with contraceptive use is therefore critical to public health. One promising pathway for improving patient outcomes is through the use of digital decision aids that assist women and their physicians in choosing a contraceptive option that women are comfortable with. Testing the ability of these aids to improve patient outcomes is therefore a necessary first step toward incorporating this technology into traditional physician appointments.

Purpose

To evaluate the effectiveness of a novel contraceptive decision aid at minimizing decisional conflict and increasing comfort with contraception among adult women.

Methods

In total, 310 adult women were assigned to use either the Tuune contraceptive decision aid or a control aid modeled after a leading online contraceptive prescriber’s patient intake form. Participants then completed self-report measures of decisional conflict, contraceptive expectations, satisfaction, and contraceptive use intentions. Individual between-subjects analysis of variance (ANOVA) models were used to examine these outcomes.

Results

Women using the Tuune decision aid (vs. those using the control aid) reported lower decisional conflict, more positive contraceptive expectations, greater satisfaction with the decision aid and recommendation, and more positive contraceptive use intentions.

Conclusions

Use of Tuune improved each of the predicted patient outcomes relative to a control decision aid. Online decision aids, particularly when used alongside physician consultations, may be an effective tool for increasing comfort with contraceptive use.

Clinical Trials Registration #

NCT05177783, ClinicalTrials.gov, https://clinicaltrials.gov/ct2/show/NCT05177783
A Turbid River of History and Law: The Procurement of Women in Imperial Japan and Colonial Korea
Authors: Kim Marie Seong-Hak
Published: June 2024

Japanese military brothels during the Pacific War, known as comfort stations, and the predicaments of women confined there still reverberate in public memory. Of late a growing number of scholars have called for approaching the comfort women issue from a broader historical context, linking it to Japan’s prewar state-regulated prostitution, later transplanted into its colonies, and human trafficking. This article discusses the legal frameworks of indentured contracts and criminal prosecution surrounding the procurement of women in imperial Japan and colonial Korea. Most women entered prostitution impressed by poverty when the law fully recognized their agency as independent contractors. The age-old machinery of advanced loan agreements, signed or guaranteed in many cases by destitute parents, revealed how the ill-guided idea of filial piety muddled the boundaries between the exercise of legal rights and their abuses. The judicial process dealing with prostitution contracts and also the crimes of abduction and kidnapping helps understand how law and state institutions operated in the Japanese colonial empire. The recent historiographical debate on the comfort women raises critical questions about the conditions under which the past is assessed.
Biological basis and treatment of frailty and sarcopenia
Authors: Sato Ryosuke , Vatic Mirela , Peixoto da Fonseca Guilherme Wesley , Anker Stefan D , von Haehling Stephan
Published: June 2024

In an ageing society, the importance of maintaining healthy life expectancy has been emphasized. As a result of age-related decline in functional reserve, frailty is a state of increased vulnerability and susceptibility to adverse health outcomes with a serious impact on healthy life expectancy. The decline in skeletal muscle mass and function, also known as sarcopenia, is key in the development of physical frailty. Both frailty and sarcopenia are highly prevalent in patients not only with advanced age but also in patients with illnesses that exacerbate their progression like heart failure (HF), cancer, or dementia, with the prevalence of frailty and sarcopenia in HF patients reaching up to 50–75% and 19.5–47.3%, respectively, resulting in 1.5–3 times higher 1-year mortality. The biological mechanisms of frailty and sarcopenia are multifactorial, complex, and not yet fully elucidated, ranging from DNA damage, proteostasis impairment, and epigenetic changes to mitochondrial dysfunction, cellular senescence, and environmental factors, many of which are further linked to cardiac disease. Currently, there is no gold standard for the treatment of frailty and sarcopenia, however, growing evidence supports that a combination of exercise training and nutritional supplement improves skeletal muscle function and frailty, with a variety of other therapies being devised based on the underlying pathophysiology. In this review, we address the involvement of frailty and sarcopenia in cardiac disease and describe the latest insights into their biological mechanisms as well as the potential for intervention through exercise, diet, and specific therapies.
Genetic characterization of KCNQ1 variants improves risk stratification in type 1 long QT syndrome patients
Authors: Morgat Charles , Fressart Véronique , Porretta Alessandra Pia , Neyroud Nathalie , Messali Anne , Temmar Yassine , Algalarrondo Vincent , Surget Elodie , Bloch Adrien , Leenhardt Antoine , Denjoy Isabelle , Extramiana Fabrice
Published: June 2024

Aims

KCNQ1 mutations cause QTc prolongation increasing life-threatening arrhythmias risks. Heterozygous mutations [type 1 long QT syndrome (LQT1)] are common. Homozygous KCNQ1 mutations cause type 1 Jervell and Lange–Nielsen syndrome (JLNS) with deafness and higher sudden cardiac death risk. KCNQ1 variants causing JLNS or LQT1 might have distinct phenotypic expressions in heterozygous patients. The aim of this study is to evaluate QTc duration and incidence of long QT syndrome–related cardiac events according to genetic presentation.

Methods and results

We enrolled LQT1 or JLNS patients with class IV/V KCNQ1 variants from our inherited arrhythmia clinic (September 1993 to January 2023). Medical history, ECG, and follow-up were collected. Additionally, we conducted a thorough literature review for JLNS variants. Survival curves were compared between groups, and multivariate Cox regression models identified genetic and clinical risk factors. Among the 789 KCNQ1 variant carriers, 3 groups were identified: 30 JLNS, 161 heterozygous carriers of JLNS variants (HTZ-JLNS), and 550 LQT1 heterozygous carriers of non-JLNS variants (HTZ-Non-JLNS). At diagnosis, mean age was 3.4 ± 4.7 years for JLNS, 26.7 ± 21 years for HTZ-JLNS, and 26 ± 21 years for HTZ-non-JLNS; 55.3% were female; and the mean QTc was 551 ± 54 ms for JLNS, 441 ± 32 ms for HTZ-JLNS, and 467 ± 36 ms for HTZ-Non-JLNS. Patients with heterozygous JLNS mutations (HTZ-JLNS) represented 22% of heterozygous KCNQ1 variant carriers and had a lower risk of cardiac events than heterozygous non-JLNS variant carriers (HTZ-Non-JLNS) [hazard ratio (HR) = 0.34 (0.22–0.54); P < 0.01]. After multivariate analysis, four genetic parameters were independently associated with events: haploinsufficiency [HR = 0.60 (0.37–0.97); P = 0.04], pore localization [HR = 1.61 (1.14–1.2.26); P < 0.01], C-terminal localization [HR = 0.67 (0.46–0.98); P = 0.04], and group [HR = 0.43 (0.27–0.69); P < 0.01].

Conclusion

Heterozygous carriers of JLNS variants have a lower risk of cardiac arrhythmic events than other LQT1 patients.
Near-field detection and peak frequency metric for substrate and activation mapping of ventricular tachycardias in two- and three-dimensional circuits
Authors: Tonko Johanna B , Lozano Cristina , Moreno Javier , Chow Anthony , Dhinoja Mehul , Lambiase Pier D
Published: June 2024

Aims

Successful ventricular arrhythmia (VA) ablation requires identification of functionally critical sites during contact mapping. Estimation of the peak frequency (PF) component of the electrogram (EGM) may improve correct near-field (NF) annotation to identify circuit segments on the mapped surface. In turn, assessment of NF and far-field (FF) EGMs may delineate the three-dimensional path of a ventricular tachycardia (VT) circuit.

Methods and results

A proprietary NF detection algorithm was applied retrospectively to scar-related re-entry VT maps and compared with manually reviewed maps employing first deflection (FDcorr) for VT activation maps and last deflection (LD) for substrate maps. Ventricular tachycardia isthmus location and characteristics mapped with FDcorr vs. NF were compared. Omnipolar low-voltage areas, late activating areas, and deceleration zones (DZ) in LD vs. NF substrate maps were compared. On substrate maps, PF estimation was compared between isthmus and bystander sites. Activation mapping with entrainment and/or VT termination with radiofrequency (RF) ablation confirmed critical sites. Eighteen patients with high-density VT activation and substrate maps (55.6% ischaemic) were included. Near-field detection correctly located critical parts of the circuit in 77.7% of the cases compared with manually reviewed VT maps as reference. In substrate maps, NF detection identified deceleration zones in 88.8% of cases, which overlapped with FDcorr VT isthmus in 72.2% compared with 83.3% overlap of DZ assessed by LD. Applied to substrate maps, PF as a stand-alone feature did not differentiate VT isthmus sites from low-voltage bystander sites. Omnipolar voltage was significantly higher at isthmus sites with longer EGM durations compared with low-voltage bystander sites.

Conclusion

The NF algorithm may enable rapid high-density activation mapping of VT circuits in the NF of the mapped surface. Integrated assessment and combined analysis of NF and FF EGM-components could support characterization of three-dimensional VT circuits with intramural segments. For scar-related substrate mapping, PF as a stand-alone EGM feature did not enable the differentiation of functionally critical sites of the dominant VT from low-voltage bystander sites in this cohort.