Static Formation Research Articles

Aspects of charged decoupled solutions in ℛ+ϖℛ2 gravity

This study deals with the physical aspects of the gravitationally decoupled solutions under [Formula: see text] gravity scenario. In doing so, charged anisotropic matter composition is assumed as the parent (seed) source for the static spherically symmetric configuration. Commencing with the Kuchowicz ansatz for the charged static parent matter formation, we establish the Karmarkar condition to thoroughly address the deformed functions and the gravitational aspects of the compact spheres. Besides these, null-complexity and isotropized conditions will enforce to grasp the system’s stability by the inclusion of charge and [Formula: see text] factors through graphical trends.

Editorial: Static and dynamic pattern formation from nano to macroscales

Editorial: Static and dynamic pattern formation from nano to macroscales

Bifurcation analysis and solitary wave solution of fractional longitudinal wave equation in magneto-electro-elastic (MEE) circular rod

In this study, we investigate the longitudinal wave equation (LWE) with the M−fractional derivative, which describes the propagation of longitudinal waves along a rod while incorporating interactions between mechanical, electrical, and magnetic fields within the material. Initially, we apply bifurcation analysis to examine the critical points or phase portraits where the system transitions to new behaviors, such as stability shifts or the emergence of chaos, and observe the mechanism of static soliton formation through a saddle-node bifurcation. Subsequently, we utilize a modified simple equation (MSE) technique to find solitary wave solutions. Depending on the relationships between free parameters, the solutions are expressed as hyperbolic, trigonometric, and exponential functions. The numerical form of the obtained solutions reveals complex phenomena, including dark and bright bell waves, kink periodic lump waves, kink periodic waves, periodic lump waves, interaction waves between kink and periodic waves, linked lump waves, and interactions of periodic and lump waves. Additionally, we compare our results with previously published work, demonstrating that the discussed methods are valuable tools for providing distinct, accurate soliton solutions relevant to nonlinear science and technology applications.

High-performance static formation of methane hydrate in fixed bed constructed by incorporating expanded graphite into polyimide foam

Hydrate has been endowed with great potential in energy storage and transportation. However, the kinetics of its formation process has been a challenge, often requiring dynamic mechanical processes that are energy-intensive and cumbersome to operate. Herein, a well-designed expanded graphite (EG)/polyimide (PI) foam was first explored as fixed bed for the formation of methane hydrate. The results demonstrate that the EG/PI fixed bed exhibits a remarkable performance in hydrate formation under static conditions, with a high gas storage capacity of 149 V/V, a short induction time and a rapid formation rate of 13.1 V·V−1·min−1 at 6 MPa and −2 °C, and excellent recyclability, which are attributed to its stable micro/macro structures. Thereinto, the pores of EG serves as gas adsorption and reaction sites, initialing the formation with extremely short induction time. The three-dimensional framework of PI foam supports the uniform dispersion of EG particles and enables the efficient formation of hydrate under static condition. The EG/PI fixed bed decreases the water freezing point and leads to a high supercooling that facilitates the rapid nucleation of hydrate. Meanwhile, the fixed bed provides extensive mass-transfer channels, sufficient growing space, and superior heat conductivity, which contribute to the hydrate growth under static condition. This work not only offers a novel strategy for fabricating high-performance fixed bed, but also provides an insight into its promotion mechanism in hydrate formation.

Integrated coupled assessment of geostorage and geothermal prospects in the oil fields of Upper Assam Basin

This study proposes an integrated approach of assessing CO2 storage potential and geothermal energy prospect based on the data of seventeen depleted wells of Upper Assam Basin which could assist the global objective of net zero transition. The petrophysical properties of Tipam, Barail and Lakadong + Therria Formations from the seventeen wells have been utilised to perform the Monte Carlo simulation for probabilistic estimation of the CO2 storage in the Upper Assam Basin. This preliminary work showed that the mean storage capacity of 18.8 ± 0.7 MT, 19.8 ± 0.9 MT and 4.5 ± 0.8 MT could potentially be stored in the three geological formations of the basin. The corrected bottom hole temperature values for the studied seventeen wells were determined using the well log data and Waples and Harrison method; these values provided a static geothermal gradient for each well, which varies widely from 0.017 to 0.033 °C/m. In order to enable geothermal prospectivity, static formation temperature maps have been generated for the studied wells. The probabilistic assessment of stored heat-in-place and formation temperature maps delimited five prospective sites for the extraction of geothermal energy in the basin. The study also presented a risk assessment for CO2 storage development in the basin. Further, the study illustrated an economic analysis of the implementation of a CO2 storage project and geothermal operations in the basin.

Temperature transient analysis: Static formation temperature test (SFTT) an overview

When drilling a geothermal well, obtaining real-time measurements of the static formation temperature is impractical due to the cooling effect of drilling fluids on the surrounding rock, which masks the actual reservoir temperatures. To overcome this, the site engineers undertake a static formation temperature test (SFTT) to ascertain the stable reservoir temperature. The present work reviews existing methods for analysing data using five different temperature sets sourced from published literature. Based on our analysis, we provide recommendations on the application of the various analytical techniques. We recommend utilising the spherical method when using bottom-hole data, whilst, for any other depth, we recommend one of the cylindrical methods. These recommendations aim to enhance the accuracy and reliability of SFTT assessments during geothermal well drilling operations.

Organic matter influence on ooid formation: New insights into classic examples (Great Salt Lake, USA; Triassic Germanic Basin, Germany)

ABSTRACTOoids are coated grains composed of a tangential or radial cortex growing around a nucleus. They are common in carbonate deposits of almost any geological age and provide insights into environmental conditions. However, abiotic or biotic factors influencing their formation remain unclear. This study aims to advance current understanding of ooid formation with a multi‐analytical approach (for example, field emission scanning electron microscopy, Raman spectroscopy and micro X‐ray fluorescence) to classic examples from Great Salt Lake, USA, and the Lower Triassic Germanic Buntsandstein Basin, Germany. Both of these deposits represent hypersaline shallow‐water environments where ooids are closely associated with microbial mats. Great Salt Lake ooids are dominantly 0.2 to 1.0 mm in size, ellipsoidal to subspherical in shape, composed of aragonite and contain organic matter. Germanic Buntsandstein Basin ooids are mainly ≤4 mm in size, spherical to subspherical in shape, composed of calcite and currently contain little organic matter. Despite the differences, both ooids have the same cortex structures, likely reflecting similar formation processes. Some Great Salt Lake ooids formed around detrital grains while others exhibit micritic particles in their nuclei. In Germanic Basin ooids, detrital nuclei are rare, despite the abundance of siliciclastic particles of various sizes in the host rocks. Germanic Basin deposits also include ‘compound ooids’, i.e. adjacent ooids that coalesced with one another during growth, suggesting static in situ development, which is supported by the lack of detrital grains as nuclei. Germanic Basin ooids also grew into laminated microbial crusts with identical microstructures, further indicating a static formation. Such microbial crusts typically form through mineral precipitation associated with organic matter (for example, extracellular polymeric substances), suggesting a similar formation pathway for ooids. The inferred key‐role of organic matter is further supported by features in radial ooids from the Great Salt Lake, which commonly exhibit, from their nuclei towards their surface, increasing organic matter contents and decreasing calcification.

Ab initio study of the processes of nitrogen functionalisation in graphene

Nitrogen functionalisation of graphene is studied with the help of ab initio electronic structure methods. Both static formation energies and energy barriers obtained from nudged elastic band calculations are considered. If carbon defects are present in the graphene structure, low energy barriers on the order of 0.5 eV were obtained to incorporate nitrogen atoms inside the sheet. For defect-free graphene, much larger barriers in the range of 3.70–4.38 eV were found, suggesting an external energy source is required to complete this type of incorporation.

Spectroscopic and thermodynamic characterization of the interaction of a new synthesized antitumor drug candidate 2H4MBBH with human serum albumin

In the present work we studied the interactions of a newly synthesized drug candidate, 2-(2-hydroxy-4-methoxybenzylidene)-1-(1H-benzimidazol-2-yl)hydrazine (2H4MBBH), with human serum albumin (HSA) by fluorescence spectroscopy. 2H4MBBH-HSA binding parameters were assessed by fluorescence quenching strategy. As made clear by the concentration data, 2H4MBBH unequivocally quenched the instrinsic HSA fluorescence. The calculated Stern-Volmer quenching constant Ksv, the Ka of 2H4MBBH-HSA complexes, as well as the thermodynamic parameters ∆H°, ∆S° and ∆G°, showed that the H-bonding forces play major part in the interaction of 2H4MBBH with HSA. These calculations point to a quenching component based on 2H4MBBH-HSA static complex formation rather than energetic collisions.

Memristor neurons and their coupling networks based on Edge of Chaos Kernel

Chua's theory of local activity shows that local activity is the origin of complexity, and the complexity can only occur on or near the stable locally active domain, referred to as Edge of Chaos (EOC). Very recently, for the voltage-controlled locally active memristors, a new physical concept dubbed “Edge of Chaos Kernel” (EOCK), which consists of a series combination between a negative resistance and a negative inductance and exhibits the EOC phenomenon of being stable yet potentially unstable, was defined and applied to the Hodgkin-Huxley neural circuit model. When an EOCK is coupled to a passive environment, its stability is disrupted, resulting in the emergence of action potentials, chaos and various complex phenomena. This paper proposes the dual version of the EOCK called as R-C EOCK, which consists of the parallel combination between a negative resistance and a negative capacitance. We show that the actual NbO memristor manufactured by NaMLab essentially belongs to a current-controlled locally active memristor which contains a R-C EOCK and gives the signature of its EOCK and EOC. We construct a second-order neuron based on the NbO memristor when connected in parallel with a passive capacitor, and further prove that only memristors endowed with an EOCK can generate action potential. On this basis, we construct a minimum cellular neural network with only 7 components based on two NbO memristor neurons and a passive coupling resistor, in which neuromorphic behaviors of static and dynamic pattern formation may emerge if and only if the single neuron has an EOCK and is poised on the EOC. The analysis in this paper explains the dynamic mechanism of Smale's paradox, in which two mathematically dead neurons coupled by a passive environment may become alive, under the same or different input current excitation, which are more in line with the actual biological neural networks.

Resilient Coordination of Nonlinear Uncertain Lagrangian Systems With Adversarial Agents: A Norm-Based Approach

In this paper, the resilient coordination problem of networked Lagrangian systems with adversarial agents is considered. A novel algorithm called Norm-Based Resilient Decision Algorithm is proposed to exclude the impact of adversarial agents. To ensure the coordination of networked Lagrangian systems, the maximum number of adversarial agents related to the robustness of the communication network is given. Under the proposed resilient consensus algorithm, secure coordination is guaranteed under adversarial agents. Then the proposed resilient controller is extended to static formation scenarios. Finally, the effectiveness of the proposed method is demonstrated through case studies and experiments. Compared to the existing results, the proposed algorithm can reduce computing resources by designing auxiliary vectors and converting them into scalars to remove extreme values.

Evaluation of the binding behavior of ellagic acid with Trypsin: Spectroscopic and computational studies

Several investigations have revealed the ability of phenolic compounds to form complexes with proteins and change their conformation. In the present paper, the interaction between trypsin and ellagic acid is studied using several techniques. The absorption investigation suggested an interaction between trypsin and ellagic acid. The fluorescence study illustrated that the hydrogen bonds and Van der Waals forces have a role in the static complex formation between trypsin and Ellagic acid (EA). On the other hand, the thermal stability study indicated that the trypsin-EA interaction could lead to a higher Tm point (47.5 to 52.5 °C) and stability for the enzyme. Based on the CD analysis, the α-helix and β-sheet percent changed after joining with ellagic acid. Ellagic acid showed an uncompetitive role in the trypsin function in the kinetic analysis. Finally, the molecular docking and simulation investigations confirmed the structural and functional alterations in the trypsin structure obtained in the spectroscopic study. The results of this study help shed more light on the trypsin behavior against the phenolic compound, especially ellagic acid.

The emergence of dynamic networks from many coupled polar oscillators: a paradigm for artificial life.

This work concerns a many-body deterministic model that displays life-like properties such as emergence, complexity, self-organization, self-regulation, excitability and spontaneous compartmentalization. The model portraits the dynamics of an ensemble of locally coupled polar phase oscillators, moving in a two-dimensional space, that under certain conditions exhibit emergent superstructures. Those superstructures are self-organized dynamic networks, resulting from a synchronization process of many units, over length scales much greater than the interaction range. Such networks compartmentalize the two-dimensional space with no a priori constraints, due to the formation of porous transport walls, and represent a highly complex and novel non-linear behavior. The analysis is numerically carried out as a function of a control parameter showing distinct regimes: static pattern formation, dynamic excitable networks formation, intermittency and chaos. A statistical analysis is drawn to determine the control parameter ranges for the various behaviors to appear. The model and the results shown in this work are expected to contribute to the field of artificial life.

Application of Artificial Intelligence in Static Formation Temperature Estimation

Application of Artificial Intelligence in Static Formation Temperature Estimation

3D Ag(I) coordination polymer sandwiched by water-muconate anionic layers: Synthesis, structure, Hirshfeld surface analysis, binding with BSA, and photocatalytic activity

The sonochemical reaction between silver salt, 1,3-bis(4-pyridylpropane (bpp) and trans,trans-muconic acid (H2muc) formed an Ag(I) coordination polymer with a 3D supramolecular sandwich architecture, {[Ag8(bpp)8(H2O)3].(muc)4.29(H2O)}n, (1) consisting of the silver-bpp cationic host that alternates with 2D water–muc guest anionic layers. The latter is formed by H-bonded water molecules-anions comprising hexagonal (H2O)6 clusters. The Hirshfeld surface and fingerprint plots have been used to quantify the weak intermolecular interactions in the crystal packing arrangement. The study showed that intermolecular hydrogen bonds are the most critical in constructing the titled supramolecular complex, accounting for 51.2% of the total Hirshfeld surface. Several spectrofluorimetric methods have been employed to investigate the binding interaction between Bovine Serum Albumin (BSA) and the titled complex. The complex induced significant fluorescence quenching of BSA, indicating a strong binding affinity for the protein. Static or ground state complex formation was envisaged as the primary quenching mechanism when the complex interacts with BSA. In addition, the Ag compound also offers photocatalytic properties by degrading the toxic organic methylene blue dye.

Study of the structure and intensity of density currents in the shelf-slope region in the Antarctic

The research involves the examination of modeling outcomes regarding the density structure and baroclinic dynamics of Antarctic shelf waters (ASW) within the shelf-slope area, encompassing a wide range of extreme weather conditions. We used a small-scale non-hydrostatic Fluidity-ICOM model to understand the formation and persistence of quasi-stationary polynyas in the Antarctic, which play a role in enhancing the formation of ASW. The salt fluxes, or buoyancy, are calculated for different forms of ice formation, namely static ice formation in young ice-covered polynyas and dynamic intra-water ice formation, which is considered the most effective and occurs in open water polynyas. Based on the intensification of ASW formation and its spread, three distinct modes of propagation along the continental slope have been identified: non-wave or subcritical mode, vortex mode, and wave or supercritical mode, which is characterized by rapid flow. The classification into different modes is determined by the internal Froude number (Fr) estimates. At the moment when the most developed stage of near-bottom density currents are transformed on a slope, the spatial dimensions of meanders, eddies, or frontal waves were found to be similar in magnitude, as well as their thickness. This observation aligns with model calculations of the local baroclinic Rossby deformation radius (RdL) for these currents. These findings agree with comparable assessments of the baroclinic Rossby deformation radius (RdL) for the Antarctic Slope Front (ASF) in the Commonwealth Sea, which were based on field observations. Additionally, the calculated propagation velocities of density currents and the density gradients at their boundaries coincide with the data obtained from field measurements. By estimating the volumetric fluxes (qv) and specific fluxes (ql) of ASW along the continental slope near the Cape Darnley coastal polynya area in the Commonwealth Sea, we can determine the contribution of ASW cascading to the formation of bottom waters under different flux regimes. The precision and accuracy of the qv and ql estimates are ensured through small-scale calculations using the non-hydrostatic Fluidity-ICOM model. These calculations consider the occurrences of intensified ASW formation in open water polynyas. Numerical experiments have revealed that a four-fold increase in a spatial step X results in an underestimation of qv by approximately 30%. As a consequence, in large-scale and even mesoscale hydrostatic models, such underestimation of qv and ql may be unsatisfactory (several times lower).

Markov modeling of phase singularity interaction effects in human atrial and ventricular fibrillation.

Atrial and ventricular fibrillation (AF/VF) are characterized by the repetitive regeneration of topological defects known as phase singularities (PSs). The effect of PS interactions has not been previously studied in human AF and VF. We hypothesized that PS population size would influence the rate of PS formation and destruction in human AF and VF, due to increased inter-defect interaction. PS population statistics were studied in computational simulations (Aliev-Panfilov), human AF and human VF. The influence of inter-PS interactions was evaluated by comparison between directly modeled discrete-time Markov chain (DTMC) transition matrices of the PS population changes, and M/M/∞ birth-death transition matrices of PS dynamics, which assumes that PS formations and destructions are effectively statistically independent events. Across all systems examined, PS population changes differed from those expected with M/M/∞. In human AF and VF, the formation rates decreased slightly with PS population when modeled with the DTMC, compared with the static formation rate expected through M/M/∞, suggesting new formations were being inhibited. In human AF and VF, the destruction rates increased with PS population for both models, with the DTMC rate increase exceeding the M/M/∞ estimates, indicating that PS were being destroyed faster as the PS population grew. In human AF and VF, the change in PS formation and destruction rates as the population increased differed between the two models. This indicates that the presence of additional PS influenced the likelihood of new PS formation and destruction, consistent with the notion of self-inhibitory inter-PS interactions.

Model test based study on icing process of long-distance water channel operating at low temperature environment

The icing problem seriously affects the efficiency of channel water delivery in low temperature conditions. A low-temperature and long-distance channel model test platform was established to study the icing process. Through this model test platform, water temperature and formation of ice cover were tested and discussed. Furthermore, the relationship between border ice width and its influencing factors were studied quantitatively. The test results show that through the recirculating flume at a negative temperature environment, the model test platform can simulate the icing process under a long-distance water delivery situation. The water temperature decreases with the increase of delivery distance and operating time. The formation of ice cover begins from the growth of border ice; however, the static formation of ice cover is rapid, but the dynamic formation of ice cover shows an obvious process of border ice lateral growth. An equation for border ice width and ice concentration was established for prediction.

Between waves and patterns: Spin wave freezing in films with Dzyaloshinskii-Moriya interaction

The relationship between waves and static pattern formation is an intriguing effect and remains unexplained in many areas of physics, including magnetism. We study the spin-wave-mediated spin reorientation transition (SRT) in magnetic films with uniaxial magnetic anisotropy and Dzyaloshinskii-Moriya interaction (DMI). In particular, we show that propagating spin waves can freeze in the SRT, causing periodic magnetic domains to arise, which is reminiscent of the wave amplitude distribution. This process can take place under the influence of a change in the magnetic field, but also of other parameters. Interestingly, at the SRT, DMI nonreciprocity leads to the emergence of flowing magnetization patterns, which suggests a spontaneous breaking of translational symmetry, and the formation of magnonic space-time crystals. The described phenomena are general and should take place in a large family of magnetic materials. Therefore, the results should be of great importance for the further development of spintronics and magnonics.

The Impact of Ammonia Fuel on Marine Engine Lubrication: An Artificial Lubricant Ageing Approach

Ammonia is a prospective zero-carbon-emission fuel for use in large marine diesel engines. Current research focuses on several technical aspects, such as injection strategies or exhaust gas aftertreatment options, but investigations regarding the impact of ammonia on engine oil degradation are largely absent from the literature. This study provides a methodology with which to evaluate this phenomenon via artificial oil alteration. By using an admixture of various contaminations to air, such as ammonia and its partial combustion product nitrogen dioxide, their respective impacts on chemical oil degradation were assessed. Subsequently, the lubricating performance of altered oils was investigated, with a focus on corrosion properties, deposit formation, and load-bearing capability. Although the application of a stoichiometric ammonia–air mixture resulted in less pronounced thermo-oxidative degradation compared to alteration with neat air, static and dynamic deposit formation as well as corrosion properties and load-bearing capability were severely impacted by the presence of ammonia. On the contrary, nitrogen dioxide contamination resulted in higher oxidation and acidification of the oil, but altered samples performed considerably better than ammonia-altered aliquots in terms of coking tendencies, corrosivity, and load bearing.