Equilibrium Approach Research Articles

Predicting the non-thermal pressure in galaxy clusters

Abstract We investigate the relationship between a galaxy cluster’s hydrostatic equilibrium state, the entropy profile, K, of the intracluster gas, and the system’s non-thermal pressure (NTP), within an analytic model of cluster structures. When NTP is neglected from the cluster’s hydrostatic state, we find that the gas’ logarithmic entropy slope, $k\equiv \mathrm{d}\ln K/\mathrm{d}\ln r$ , converges at large halocentric radius, r, to a value that is systematically higher than the value $k\simeq1.1$ that is found in observations and simulations. By applying a constraint on these ‘pristine equilibrium’ slopes, $k_\mathrm{eq}$ , we are able to predict the required NTP that must be introduced into the hydrostatic state of the cluster. We solve for the fraction, $\mathcal{F}\equiv p_\mathrm{nt}/p$ , of NTP, $p_\mathrm{nt}$ , to total pressure, p, of the cluster, and we find $\mathcal{F}(r)$ to be an increasing function of halocentric radius, r, that can be parameterised by its value in the cluster’s core, $\mathcal{F}_0$ , with this prediction able to be fit to the functional form proposed in numerical simulations. The minimum NTP fraction, as the solution with zero NTP in the core, $\mathcal{F}_0=0$ , we find to be in excellent agreement with the mean NTP predicted in non-radiative simulations, beyond halocentric radii of $r\gtrsim0.7r_{500}$ , and in tension with observational constraints derived at similar radii. For this minimum NTP profile, we predict $\mathcal{F}\simeq0.20$ at $r_{500}$ , and $\mathcal{F}\simeq0.34$ at $2r_{500}$ ; this amount of NTP leads to a hydrostatic bias of $b\simeq0.12$ in the cluster mass $M_{500}$ when measured within $r_{500}$ . Our results suggest that the NTP of galaxy clusters contributes a significant amount to their hydrostatic state near the virial radius and must be accounted for when estimating the cluster’s halo mass using hydrostatic equilibrium approaches.

Financial Literacy, Portfolio Choice, and Wealth Inequality: A General Equilibrium Approach

Financial Literacy, Portfolio Choice, and Wealth Inequality: A General Equilibrium Approach

Probabilistic Analysis of Slope Using Finite Element Approach and Limit Equilibrium Approach around Amalpata Landslide of West Central, Nepal

Probabilistic Analysis of Slope Using Finite Element Approach and Limit Equilibrium Approach around Amalpata Landslide of West Central, Nepal

Slouching Towards Decentralization. An Equilibrium Approach for Collective Bargaining

Slouching Towards Decentralization. An Equilibrium Approach for Collective Bargaining

Synergetic and advanced isotherm investigation for the enhancement influence of zeolitization and β-cyclodextrin hybridization on the retention efficiency of U(vi) ions by diatomite.

In synergetic investigations, the adsorption effectiveness of diatomite-based zeolitic structure (ZD) as well as its β-cyclodextrin (CD) hybrids (CD/ZD) towards uranium ions (U(vi)) was evaluated to examine the influence of the transformation procedures. The retention behaviors and mechanistic processes have been demonstrated through analyzing the steric and energetic factors employing the modern equilibrium approach (a monolayer model with a single energy level). After the saturation phase, the uptake characteristics of U(vi) were dramatically improved to 297.5 mg g-1 after the CD blending procedure versus ZD (262.3 mg g-1) or 127.8 mg g-1. The steric analysis indicated a notable increase in binding site levels after the zeolitization steps (Nm = 85.7 mg g-1) as well as CD implementation (Nm = 91.2 mg g-1). This finding clarifies the reported improvement in the ability of CD/ZD to effectively retain the U(vi) ions. Furthermore, every single active site of the CD/ZD material has the capacity to adsorb around four ions, which are aligned according to a vertical pattern. The energetic aspects, specifically Gaussian energy (<8 kJ mol-1) along with retention energy (<40 kJ mol-1), validate the regulated influences of the physical mechanistic processes. The physical adsorption of U(vi) seems to depend on various intermolecular forces, such as van der Waals forces, in conjunction with zeolitic ion exchanging pathways (0.6-25 kJ mol-1). The thermodynamic assets have been evaluated to confirm the exothermic together with spontaneous adsorption U(vi) by ZD and its blend with CD (CD/ZD).

Innovation and Welfare Impacts of Disclosure Regulation: A General Equilibrium Approach&amp;nbsp;

Innovation and Welfare Impacts of Disclosure Regulation: A General Equilibrium Approach&amp;nbsp;

Analysis of a Nailed Soil Slope Using Limit Equilibrium and Finite Element Methods – A Review

Reviewing the two most used techniques for slope stability analysis is the goal of this research. The analysis derived from PLAXIS 2D (finite element based) and SLOPE/W (limit equilibrium based). Two 45degree and 60-degree slope angles that are strengthened with nails at three different inclinations—0, 15, and 30—are used for the analysis. All nail inclinations and slope angles are measured from the horizontal. A comparative analysis of stability metrics, including critical slip surfaces, nail forces, and factor of safety, has been conducted. It is discovered that the limit equilibrium approach produces greater values of the factor of safety when compared to the finite element method. There are notable differences between the failure surfaces obtained from the two methods.Large nail forces are seen using the LEM approach for 45 slopes with all nail inclinations, however the FEM method indicates an increase in the nail forces for 60 slope angles. In conclusions, both FEM and LEM methods have advantages and disadvantages. These two methods give the precise results if both methods are combined. The analysis using the LEM to compute the factor of safety are further enhanced with the Finite Element using PLAXIS 3D to compute the stress strain displacement of the soil with added soil nailing or structure member such as retaining wall.

Revisiting the effect of financial crisis and banking reforms on the effectiveness of monetary policy transmission mechanism in Nigeria

Understanding the effect of the extent of financial intermediation on the performance of monetary policy transmission channels is crucial to the formulation of monetary policy. To this end, the paper tested the validity of the above statement in the Nigerian context using quarterly data between 2005Q1 and 2019Q4. The data was analysed using a dynamic stochastic general equilibrium approach. Results of the estimation showed that the financial crisis experienced in the country led to the depression of the Nigerian capital market and a decrease in the amount of credit provided by banks for trading in the capital market, exchange rate risk tightening of liquidity, and greater loan-loss provisioning. It was revealed that recent changes and reforms in the industry have positive impacts on all the monetary policy transmission channels (exchange rate, interest rate, expectation, and credit) considered in the study. However, the credit channel appeared to be the most active as it transmits the largest impact of shocks to the financial sector (88.06 per cent on average) to the real economy. This demonstrates that the private sector depended on the financial sector for ?nancing their expenditures, which later induced an increase in the level of investment and increased output.

Halving the European farm uses of pesticides: Looking for alternative technologies

Abstract With the Green Deal roadmap, the European Union aims to half the uses and risks of pesticides by the end of this decade. The European Commission (EC) claims that the proposal for pesticides will not disrupt European agri-food production and price. The EC argues that previous assessments of the roadmap provide an upper limit to the effects of the proposal, mostly by ignoring alternative production techniques that rely on integrated pest management principles. Our paper first explains that the general equilibrium approach applied by the United States Department of Agriculture (USDA) does correctly capture these alternatives, measured implicitly in econometric studies on the price inelasticity of pesticide use. Second, we show that the USDA study significantly underestimates the negative effects of the proposal in terms of agri-food production due to the input taxes rebated as output subsidies. Finally, we show that the underestimation is robust to the other arguments raised by the EC.

Equilibrium decisions of electricity and ancillary services for energy storage in a renewable power system

Mitigating the power supply fluctuations and maintaining profitability is essential for the operation of the renewable power system (RPS). This study examines, from a supply chain perspective, how the decisions of generators with energy storage technologies (ESTs) in the electricity market (EM) and ancillary services market (ASM) will affect the volatility and profitability of the RPS. The supply chain network equilibrium approach is adopted to investigate the optimal transaction prices and volumes among various decision-makers in the network with the objectives of maximizing profits. The equilibrium conditions are presented with the variational inequality theory and a modified projection algorithm. A case study based on a real situation is carried out and the results show that: (1) When ESTs are used in the EM only, it works well on smoothing the fluctuations of electricity output and price. (2) ESTs, when used in the ASM, can significantly improve the profitability of both the generator and the RPS. (3) When ESTs are used in both the EM and ASM, ancillary services account for approximately 84 % of storage capacity. In addition, ESTs can also promote the consumption of renewable power. This study provides valuable insights for informed decisions to enhance the economic and stable operation of the RPS.

The evolution of sulphur-bearing molecules in high-mass star-forming cores

Context. To understand the chemistry of sulphur (S) in the interstellar medium, models need to be tested by observations of S-bearing molecules in different physical conditions. Aims. We aim to derive the column densities and abundances of S-bearing molecules in high-mass dense cores in different evolutionary stages and with different physical properties. Methods. We analysed observations obtained with the Institut de RadioAstronomie Millimétrique (IRAM) 30 m telescope towards 15 well-known cores classified in the three main evolutionary stages of the high-mass star formation process: high-mass starless cores, high-mass protostellar objects, and ultracompact HII regions. Results. We detected rotational lines of SO, SO+, NS, C34S, 13CS, SO2, CCS, H2S, HCS+, OCS, H2CS, and CCCS. We also analysed the lines of the NO molecule for the first time to complement the analysis. From a local thermodynamic equilibrium approach, we derived the column densities of each species and excitation temperatures for those that are detected in multiple lines with different excitation. Based on a statistical analysis of the line widths and the excitation temperatures, we find that NS, C34S, 13CS, CCS, and HCS+ trace cold, quiescent, and likely extended material; OCS, and SO2 trace warmer, more turbulent, and likely denser and more compact material; SO and perhaps SO+ trace both quiescent and turbulent material, depending on the target. The nature of the emission of H2S, H2CS, and CCCS is less clear. The molecular abundances of SO, SO2, and H2S show the strongest positive correlations with the kinetic temperature, which is thought to be an indicator for evolution. Moreover, the sum of all molecular abundances shows an enhancement of gaseous S from the less evolved to the more evolved stages. These trends could be due to the increasing amount of S that is sputtered from dust grains owing to the increasing protostellar activity with evolution. The average abundances in each evolutionary group increase, especially in the oxygen-bearing molecules, perhaps due to the increasing abundance of atomic oxygen with evolution owing to photodissociation of water in the gas phase. Conclusions. Our observational work represents a test-bed for theoretical studies aimed at modelling the chemistry of sulphur during the evolution of high-mass star-forming cores.

Local density dependent potentials for an underlying van der Waals equation of state: A simulation and density functional theory analysis.

There is an ever increasing use of local density dependent potentials in the mesoscale modeling of complex fluids. Questions remain, though, about the dependence of the thermodynamic and structural properties of such systems on the cutoff distance used to calculate these local densities. These questions are particularly acute when it comes to the stability and structure of the vapor/liquid interface. In this article, we consider local density dependent potentials derived from an underlying van der Waals equation of state. We use simulation and density functional theory to examine how the bulk thermodynamic and interfacial properties vary with the cutoff distance, rc, used to calculate the local densities. We show quantitatively how the simulation results for bulk thermodynamic properties and vapor-liquid equilibrium approach the van der Waals limit as rc increases and demonstrate a scaling law for the radial distribution function in the large rc limit. We show that the vapor-liquid interface is stable with a well-defined surface tension and that the interfacial density profile is oscillatory, except for temperatures close to critical. Finally, we show that in the large rc limit, the interfacial tension is proportional to rc and, therefore, unlike the bulk thermodynamic properties, does not approach a constant value as rc increases. We believe that these results give new insights into the properties of local density dependent potentials, in particular their unusual interfacial behavior, which is relevant for modeling complex fluids in soft matter.

A multi-time-scale wall model for large-eddy simulations and applications to non-equilibrium channel flows

The recent Lagrangian relaxation towards equilibrium (LaRTE) approach (Fowleret al.,J. Fluid Mech., vol. 934, 2022, A44) is a wall model for large-eddy simulations (LES) that isolates quasi-equilibrium wall-stress dynamics from non-equilibrium responses to time-varying LES inputs. Non-equilibrium physics can then be modelled separately, such as the laminar Stokes layers that form in the viscous region and generate rapid wall-stress responses to fast changes in the pressure gradient. To capture additional wall-stress contributions due to near-wall turbulent eddies, a model term motivated by the attached eddy hypothesis is proposed. The total modelled wall stress thus includes contributions from various processes operating at different time scales (i.e. the LaRTE quasi-equilibrium plus laminar and turbulent non-equilibrium wall stresses) and is called the multi-time-scale (MTS) wall model. It is applied in LES of turbulent channel flow subject to a wide range of unsteady conditions from quasi-equilibrium to non-equilibrium. Flows considered include pulsating and linearly accelerating channel flow for several forcing frequencies and acceleration rates, respectively. We also revisit the sudden spanwise pressure gradient flow (considered in Fowleret al.,J. Fluid Mech., vol. 934, 2022, A44) to review how the newly introduced model features affect this flow. Results obtained with the MTS wall model show good agreement with direct numerical simulation data over a vast range of conditions in these various non-equilibrium channel flows. To further understand the MTS model, we also describe and test the instantaneous-equilibrium limit of the MTS wall model. In this limit, good wall-stress predictions are obtained with reduced model complexity but providing less complete information about the wall-stress physics.

A novel cartoon crosslinked β-cyclodextrin (C-β-CD) polymer for effective uptake of Hg from aqueous solutions: Kinetics, equilibrium, thermodynamics, and statistical physics approach

A novel cartoon crosslinked β-cyclodextrin (C-β-CD) polymer was obtained by crosslinking β-CD unities and cellulosic fibers of paper towel cardboard via esterification using citric acid. C-β-CD polymer was used as an adsorbent to uptake Hg from aqueous matrices, and kinetics, equilibrium, thermodynamics, and statistical physics were evaluated. It was found that the C-β-CD polymer was successfully synthesized and was a promising adsorbent to remove Hg from aqueous solution, achieving a removal percentage higher than 90 % and a maximum adsorption capacity of 211.3 mg g−1. The best operational adsorption conditions were a pH of 5.0, an adsorbent dosage of 0.5 g/L, 270 min, and 328 K. Besides, the pseudo-second-order model well-described the adsorption kinetics, and the Langmuir model better represented the equilibrium. The thermodynamic studies pointed to spontaneous and endothermic adsorption. The positive effect of the temperature on the process was also confirmed by the statistical physics approach, where the number of ions adsorbed per site increased with increasing temperature. It was suggested that electrostatic interaction was the main interaction mechanism responsible for the good performance of the novel C-β-CD polymer. In addition, the adsorbent proved to be effective for three adsorption cycles. Finally, it can be concluded that a novel C-β-CD adsorbent was prepared using an easy and green technique, and the obtained material is promising to separate Hg from contaminated waters.

Evaluation of corporate income tax rates reduction policy applied to the general equilibrium approach and the degree of self-financing method

The reduction of the corporate income tax rate from 25% to 22% in 2020 is one of the Indonesian government's initiatives to hasten the country's economic recovery in response to the COVID-19 pandemic. In this paper, we aim to evaluate those policies’ impact on other tax revenue policies. According to our estimation using the General Equilibrium approach and the Degree of Self Financing (DSF) method, the measurement results demonstrate that nearly a quarter of 93,8% from the total lost tax revenue resulting from the policy of lowering the corporate income tax rate will be made up for by an increase in other tax revenues in the form of: 17.55 percent of individual income tax revenue, 5.94 percent of VAT, and 0.000197 percent of Tax on Deposits. However, given that only a quarter of 93,8% from the lost corporate income tax revenue will be recovered, the government's decision to keep the corporate income tax rate at 22 percent in 2022 and beyond is still reasonable.

The Russia-Ukraine War and Its Impact on the Food Security of Korea, China, and Japan: A CGE Approach

Purpose - In 2021, Ukraine and Russia exported 12% and 17% of global wheat, being significant grain producers and exporters. However, Russia’s invasion of Ukraine greatly impacts Ukraine’s wheat production and trade. In this regard, this study examines the impact of Russia’s invasion of Ukraine on global food security using the computable general equilibrium approach.&#x0D; Design/Methodology/Approach - We utilized the global multi-sector standard GTAP model, specifically the GTAP Database Version 11, with a base year of 2017. For this research purpose, the original 160 regions and 65 sectors of the GTAP database were aggregated into 23 regions and 24 sectors. Due to the uncertain nature of the conflict duration between Russia and Ukraine, we designed three scenarios: Slight, Medium, and Severe. Each scenario represents varying degrees of wheat production, trade disruption, and an increase in wheat production by third producers for shocks.&#x0D; Findings - The study reveals several effects: real GDP decreases for Ukraine, Russia, Turkey, India, and Georgia, while countries like Egypt, Turkey, Azerbaijan, India, Korea, and Japan experience diminished economic welfare. Russia’s invasion can affect wheat imports of countries like Turkey, India, Mongolia, and Egypt. Ukraine, Egypt, Turkey, and India registered trade surpluses, while others recorded deficits&#x0D; Research Implications - The ongoing conflict complicates assessing long-term consequences on global food security. Policymakers are advised to monitor closely, implement strategies to mitigate disruptions, and foster international collaboration to alleviate adverse effects on trade, economies, and food security, particularly of nations heavily reliant on Ukraine’s wheat exports, like Egypt, Turkey, Mongolia, Georgia, and Azerbaijan.

Influence of Root Reinforcement on Shallow Landslide Distribution: A Case Study in Garfagnana (Northern Tuscany, Italy)

In this work, we evaluated the influence of root structure on shallow landslide distribution. Root density measurements were acquired in the field and the corresponding root cohesion was estimated. Data were acquired from 150 hillslope deposit trenches dug in areas either devoid or affected by shallow landslides within the Garfagnana Valley (northern Tuscany, Italy). Results highlighted a correlation between the root reinforcement and the location of measurement sites. Namely, lower root density was detected within shallow landslides, with respect to neighboring areas. Root area ratio (RAR) data allowed us to estimate root cohesion by the application of the revised version of the Wu and Waldron Model. Then, we propose a new method for the assimilation of the lateral root reinforcement into the infinite slope model and the limit equilibrium approach by introducing the equivalent root cohesion parameter. The results fall within the range of root cohesion values adopted in most of the physically based shallow landslide susceptibility models known in the literature (mean values ranging between ca. 2 and 3 kPa). Moreover, the results are in line with the scientific literature that has demonstrated the link between root mechanical properties, spatial variability of root reinforcement, and shallow landslide locations.

Comparison of Equilibrium and Nonequilibrium Approaches for Relative Binding Free Energy Predictions.

Alchemical relative binding free energy calculations have recently found important applications in drug optimization. A series of congeneric compounds are generated from a preidentified lead compound, and their relative binding affinities to a protein are assessed in order to optimize candidate drugs. While methods based on equilibrium thermodynamics have been extensively studied, an approach based on nonequilibrium methods has recently been reported together with claims of its superiority. However, these claims pay insufficient attention to the basis and reliability of both methods. Here we report a comparative study of the two approaches across a large data set, comprising more than 500 ligand transformations spanning in excess of 300 ligands binding to a set of 14 diverse protein targets. Ensemble methods are essential to quantify the uncertainty in these calculations, not only for the reasons already established in the equilibrium approach but also to ensure that the nonequilibrium calculations reside within their domain of validity. If and only if ensemble methods are applied, we find that the nonequilibrium method can achieve accuracy and precision comparable to those of the equilibrium approach. Compared to the equilibrium method, the nonequilibrium approach can reduce computational costs but introduces higher computational complexity and longer wall clock times. There are, however, cases where the standard length of a nonequilibrium transition is not sufficient, necessitating a complete rerun of the entire set of transitions. This significantly increases the computational cost and proves to be highly inconvenient during large-scale applications. Our findings provide a key set of recommendations that should be adopted for the reliable implementation of nonequilibrium approaches to relative binding free energy calculations in ligand-protein systems.

Mathematical and numerical modelling of rapid transients at partially lifted sluice gates

In the present paper, we study the mathematical and numerical modelling of rapid transients at partially lifted sluice gates in the context of one-dimensional Shallow water Equations. First, improved exact solutions of the dam-break problem with partially lifted gate are presented, assuming (i) the dependence of the gate contraction coefficient on the upstream flow depth, and (ii) a viable definition of the submerged flow equation. We show that an exact dam-break solution always exists for any set of initial conditions, but there are also initial conditions for which the solution is multiple. To cope with this case, a novel disambiguation criterion based on the continuous dependence of the solution on the initial conditions is used to select the physically congruent choice amongst the alternatives. Finally, we present a one-dimensional Finite Volume numerical model for the approximate solution of the Shallow water Equations equipped with an approximate Riemann solver for the sluice gate treatment at cells interfaces. The numerical experiments show that the embedding of the steady state gate equations (equilibrium approach) into the approximate Riemann solver leads to unsatisfactory dam-break simulations, while a novel relaxed version of the gate equations (non-equilibrium approach) supplies results that are in agreement with both the novel exact solutions and the laboratory dam-break results available from the literature.

Aspen Plus model of a downdraft gasifier for lignocellulosic biomass adjusted by Principal Component Analysis

The development and improvement of biomass gasification processes have been accelerated by the use of computational tools for process simulation, exploring their feasibility under different conditions and identifying key parameters that are validated through real experiments, contributing to maturing a gasification technology from laboratory to commercial scale. This work presents an Aspen Plus model of a small-scale downdraft gasifier using biomasses with different elemental and proximate analyses, combining stoichiometric and non-stoichiometric equilibrium approaches. The pyrolysis, oxidation, and reduction processes in the proposed model were separated into distinct steps, with the first one based on Gibbs energy minimization and the latter based on stoichiometric equilibrium models. A representative tar composition, with a production ratio to gas production based on literature, was considered as an input parameter to the model. The obtained data were analyzed using principal component analysis (PCA) to investigate the relations between equivalence ratio (ER), fixed carbon and volatile material ratio FCMV, the CO conversion through methanation (Mconv), carbon conversion via hydrogasification (Hconv), and the mean residual sum of square MRSS. The most significant results obtained from this study include the successful adjustment of the model to represent the gasification of different biomasses, particularly in correcting the H2 and CH4 concentrations. Notably, the adjustment resulted in a substantial reduction of the MRSS deviation from an average of 94.7% to an average of 7.2% concerning reported results in the literature. These findings demonstrate the accuracy of the model in simulating the gasification process and highlight the importance of considering CH4 reactions adjustment for more reliable predictions. The achieved adjustments are valuable insights for advancing gasification technology towards engineering applications.