Gutierrez and Urroz (2023) have proposed a family of local permutation polynomials over finite fields of arbitrary characteristic based on a class of symmetric subgroups without fixed points called e-Klenian groups. The polynomials within this family are referred to as e-Klenian polynomials. Furthermore, they have shown the existence of companions for the e-Klenian polynomials when the characteristic of the finite field is odd. Here, we construct three new families of local permutation polynomials over finite fields of even characteristic, and derive a necessary and sufficient condition for each of these families to achieve the maximum possible degree. We also consider the problem of the existence of companions for the e-Klenian polynomials over finite fields of even characteristic. More precisely, we prove that over finite fields of even characteristic, the 0-Klenian polynomials do not have any companions. However, for e >= 1, we explicitly provide a companion for the e-Klenian polynomials. Moreover, we provide a companion for each of the new families of local permutation polynomials that we introduce. (c) 2025 Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
. This paper considers permutation polynomials over the finite field Fq2 by utilizing low-degree permutation rational functions over Fq, where q is a prime power. As a result, we obtain two classes of permutation binomials, six classes of permutation quadrinomials and six classes of permutation pentanomials over Fq2 . Additionally, we show that the obtained binomials, quadrinomials and pentanomials are quasi-multiplicative inequivalent to the known ones in the literature.
This research proposes a novel passive heat transport device called a thermosyphon heat transport device (THTD) for indoor solar cooking applications. While heat pipes are generally regarded as efficient devices for energy transport, their use in concentrated solar power plants and long-distance heat transport remains limited. The performance of the THTD depends on three main factors: coolant flow rate, heat load, and its geometry including the elevation difference between the heat sink and the heat source. In this paper, a steady-state computational fluid dynamics analysis is performed using Fluent to evaluate its performance at a specific coolant flow rate (3 lpm), considering four different heat loads (i.e. 200, 400, 500, and 700 W). Water is used as the secondary fluid to extract heat from the primary fluid at the cooler section. The analysis focused on comparing the simulation results with experimental data on the temperature difference across the heater and the mass flow rate within the THTD. The findings revealed that as the heat load increased, the temperature difference across the heater also rose, along with the mass flow rate. The results indicated that laminar flow was maintained within the THTD for all heat power levels considered in the analysis.
The study of meteorological to hydrological drought propagation over the Betwa river basin is essential for effective water management. Meteorological and hydrological droughts were analysed using the Standardized Precipitation Evapotranspiration Index and Standardized Runoff Index, respectively. The meteorological and hydrological droughts were computed for historical (1991-2000), T1 (2001-2050), and T2 (2051-2100) periods. The drought propagation time and propagation rate over these periods were evaluated to understand the drought transition behavior under a changing climate. Results indicate intensified drought severity and duration in future scenarios, particularly under high-emission pathways. Drought propagation time is projected to decrease by up to 80% in the T2 period (2051-2100), accelerating drought transitions. The Dhasan sub-basin and Lower Betwa Basin exhibit the highest propagation rates (42% and 33% in T1, increasing to 63% and 50% in T2 under SSP585). The study highlights the urgent need for adaptive water management strategies to mitigate increasing drought risks.
Hydrate-based CO2 storage (HBCS) in subsea sediments has emerged as a promising climate mitigation method due to its high CO2 storage capacity and long-term stability. However, practical application encounters significant challenges due to sluggish CO2 hydrate formation kinetics, primarily resulting from limited liquid CO2-water interfacial contact after CO2 hydrate film formation and blockage. Generating CO2 microdroplets in continuous aqueous phase forms CO2(L) in H2O (C/W) emulsion, which enhances CO2 dispersion and expands the liquid-liquid interfacial area. However, effective methods to synthesize stable C/W emulsion under high pressures and their role in enhancing CO2 hydrate formation kinetics is less understood and warrant systematic investigation. In this study, we formulate C/W emulsion using an environmentally benign non-ionic surfactant alkyl polyglucoside (APG), and systematically examine the effects of APG concentrations and stirring rates on C/W emulsion stability in a fully-visual reactor. Under optimal 3.0 wt% APG, C/W emulsion forms under 1800 rpm in 13 s and maintains stability for similar to 7 hrs with average CO2 micro-droplet size of similar to 14 mu m. The dispersion of liquid CO2 microdroplets promotes ultra-rapid CO2 hydrate formation, achieving a CO2 uptake of 187.8 v(CO2)/v(H2O) (water conversion of 94.8%) with t(90) of 40 min, representing a ten-fold increase compared to the conventional CO2(L)-H2O mixing system by stirring. Findings of this study will guide effective methods for synthesizing and improving the stability of C/W emulsion under high pressure. Moreover, enhanced CO2 hydrate formation kinetics enabled by emulsion-based method can be applied in a series of CO2 hydrate-based applications. The study offers both mechanistic insights and practical guidance for future field-scale HBCS deployment.
