This paper investigates density-driven flow in porous media, focusing on the roles of viscosity contrast, density contrast, and linear adsorption. In this setup, the fluid on top is heavier and more viscous than the fluid below. Under the effect of gravity, this system becomes unstable, and finger-like structures appear. The phenomenon is described mathematically by coupling Darcy's law with a convection-diffusion reaction equation. The nonlinearity in this model arises mainly from the concentration dependence of viscosity and the convective transport term. The existence of a unique pair of weak solutions is shown using the Galerkin approximation method and truncation technique. Moreover, an application of the maximum principle shows non-negativity of the concentration. Additionally, we analyze the long-time behavior of the solution and prove that the concentration converges exponentially to zero in the U-norm for all 1 <= p <= infinity as t -> infinity. To complement the theoretical analysis, we perform numerical simulations based on a pressure formulation. By tracking total kinetic energy and mixing measures over time, we discuss the instability and the mixing efficiency, respectively. The present study reveals that although increasing the density contrast amplifies the total kinetic energy, the marginal impact diminishes with successive increments of density contrast. Similarly, while adsorption acts to suppress mixing, its efficiency in doing so tends to saturate with further increases. These behavior are consistent with the numerical simulations.
In this study, we reconstruct the dark energy (DE) as a Dirac-Born-Infeld (DBI) scalar field from the Hubble dataset (32 CC + 26 BAO) and the DESI dataset using the Gaussian process (GP). As the GP is a non-parametric and model-independent way to reconstruct a function and its derivative using the data, our reconstruction of the DE equation of state, the DE density parameter, and the potential does not assume any particular model of cosmology. Using Monte Carlo realizations of the GP-reconstructed expansion history, we derive a posterior estimate of the Hubble constant, obtaining H0=69.53±2.68 km s−1 Mpc−1. This method offers a fully model-independent estimate of H0, relying only on data and GP priors, and provides an unbiased intermediate value useful for reassessing the Planck-SH0ES tension. Using the reconstructed profiles of the scalar potential as a function of the field ϕ, along with their associated uncertainties, we perform a chi-square curve fitting procedure to assess the viability of four different scalar field potentials, such as Exponential, Power-law, Free Field (quadratic), and Higgs-like potential. This allows us to identify which potential best fits the reconstructed data. We also employ MCMC analysis to place quantitative constraints on the model parameters associated with each potential. Furthermore, we do a χ2 analysis for all four potentials and comment on the goodness of the fit for each of them. Finally, we discuss possible generalizations of our model-independent framework and outline the phenomenological implications of our findings.
This study examines plasma-induced bubble behaviour and mass-transfer intensification using a plasma bubble reactor. The reactor consists of eight 200 μm holes to generate millimeter-scale bubbles in glycerol water or sodium dodecyl sulphate (SDS) solutions. This small bubble column enables the identification of unique plasma-induced reactions inside the bubbles for subsequent gas–liquid absorption. High-speed imaging shows that plasma activation reduces bubble diameter, narrows size distribution, shortens attachment time, and increases post-detachment path length, effectively extending the reaction window. This behaviour is strongly governed by liquid properties: low-viscosity, high-surface-tension media (water, SDS) support stable plasma bubbles, while higher glycerol concentrations decrease the volumetric mass-transfer coefficient substantially. OES indicates a gliding-arc-like discharge dominated by N2 SPS/FNS, OH, and O emissions, suitable for NO/NO2 chemistry but not for low-temperature pathways such as ozone formation. Plasma oscillations generate ultrasonication-like interfacial renewal, while plasma enhance microturbulence throughout the 150 mL bath, yielding a higher absorption rate of reactive species than that achieved in conventional small bubble columns. Force-balance analysis (buoyancy, drag, Basset, surface tension, gas momentum) clarifies how plasma modifies interfacial stress to bubble size, detachment time to improve gas–liquid absorption. Overall, plasma bubbles operate as mobile microreactors, coupling intensified hydrodynamics with reactive plasma chemistry to achieve superior mass-transfer effect.
PurposeThe cold chain system is vital for food safety, public health, and sustainability. However, it still faces challenges in sustainable practices, especially in quality assurance, waste reduction, and efficiency. This study uses bibliometric and systematic review methods to trace the field's development over 25 years, identify gaps in global benchmarking, and propose practical performance metrics. Applying SPAR-4 and bibliometric tools, the study finds growing academic interest in cold chains since 2010 and stresses the need for standardized global indicators. A new KPI framework is presented to enable cross-regional comparisons and guide future research and policy.Design/methodology/approachThe study presents a comprehensive bibliometric analysis of research on cold chain management published over the last 25 years. In addition, the SPAR-4 framework is applied to ensure methodological rigor in the systematic literature review process. Drawing on publications spanning 2000 to 2025, the analysis traces the evolution and trajectory of cold chain management research and examines its implications for business and logistics practices.FindingsBibliometric results show that cold chain publications experienced an 88% annual increase in citations from 2010 to 2025, compared with 2000-2009, highlighting rising academic interest. Most research centers on vaccine and food supply chains. The review also notes the absence of standardised global indicators for evaluating the cold chain. It suggests key dimensions: sustainability, safety and quality, operational performance, capacity, and integration with broader supply chains.Originality/valueThis study provides a comprehensive synthesis of cold chain management research, highlights key limitations in existing approaches, and identifies priority areas for future investigation. By proposing a structured KPI framework, it provides practical guidance to support the adoption and evaluation of sustainable cold-chain management practices.
This study investigates the fabrication of aluminium die-casting (ADC-10) composites with varying weight percentages of boron carbide (B4C) particles, using Al-5Ti-B as a grain refiner through mechanical automatic feeder stir squeeze casting process. Five compositions are developed: pure ADC-10 and blends with 0.5%, 1%, 2%, and 3% B4C, designated R-0, R-0.5, R-1, R-2, and R-3, each containing Al-5Ti-B grain refiner. The samples having 2 wt.% of B4C exhibit maximum grain refinement. As a result significant enhancement in hardness and toughness values are observed. However, the increase in higher reinforcement level (3 wt.%) leads to particle agglomeration thereby negatively impacting the mechanical properties. Fracture studies have indicated increased brittle failure with more B4C content, while the best specific strength and elongation are achieved at sample containing 2 wt.%, B4C. This can be attributed to improved interfacial strength and uniform particle distribution. Overall, the combination of B4C reinforcement and grain refinement with mechanical stir casting notably enhanced the mechanical strength of the composites, underlining the importance of particle uniformity and nucleation site development in improving mechanical properties.
