State Equilibrium Research Articles

Predicting changes in soil organic carbon after a low dosage and one-time addition of biochar blended with manure and nitrogen fertilizer

Modeling plays an important role in predicting the long-term effects of biochar on soil organic carbon dynamics. The objective of our study was to apply the Century model to assess changes in temporal soil organic carbon in soil amended with manure and nitrogen fertilizer (MN), with manure and biochar (MB) or with manure, nitrogen fertilizer and biochar (MNB). We determined that, after 115 years, soil organic carbon stocks could not reach a steady state (equilibrium) or pre-cultivation levels, regardless of amendment type. Our results showed that a biennial input of manure and nitrogen fertilizer (MN) led to a 84% increase in soil organic carbon compared to a 79% (MNB) and 70% (MB) increase when amendments contained biochar. However, the quantity of organic matter input from crop residues and amendments was sufficient to increase the active fraction, with a turnover time of months to years, by 86%. In fact, carbon associated with the slow fraction, with a turnover time of 20 to 50 years, was the key driver for soil organic carbon accumulation in all amendment types. Although the passive fraction is the most stable form of carbon in the soil, with a turnover time of 400 to 100 years, once manure and biochar were added to the soil, this fraction increased up to 32%. Our results provided further insight into the ability of Century to accurately predict changes in soil organic carbon stocks when a combination of manure, nitrogen fertilizer or biochar were added to soil. Century predicted soil organic carbon stocks within -1% to +9% of measured values. However, further fine-tuning of the model is required since biochar undergoes chemical transformations (e.g., ageing) and changes soil physical parameters (e.g., bulk density) that can not be currently accounted for in the Century model. Addressing these limitations of Century will also help to increase the relationship between measured and predicted values.

Time History of Maximum Bearing Temperature Based on a Simplified Thermohydrodynamic Lubrication Theory

An overshoot phenomenon of bearing temperature in hydrodynamic journal bearings may be observed during a sudden start-up experiment. This phenomenon implies that the maximum bearing temperature in acceleration operation may exceed the predicted one which can be predicted accurately by applying a state-of-the-art steady state thermohydrodynamic lubrication (THL) model. This paper presents the maximum bearing temperature including the one during acceleration operation by using a simplified THL model that is newly proposed for a transient THL analysis. It is found that the overshooted temperature can be qualitatively predicted by using the transient THL model that incorporates properly the interaction between the motion of journal center and the viscous dissipation, even if it is a simple model. Next, the transient temperature during slow acceleration operation and also those toward higher dimensional steady state journal rotational speed are calculated and they are found to be in qualitative agreement with the measurements. The oil film characteristics such as oil film pressure, temperature and thickness after reaching the steady state equilibrium do not depend on the value of initial journal eccentricity ratio in the transient analysis. However, when the values are different, the characteristics immediately after starting rotation change largely. In the case of the value 1.00, it is found to give a prediction that agrees qualitatively with the characteristics measured in the experiment.

The future fate of the Dead Sea: Total disappearance or a dwarfed hypersaline hot lake?

An energy balance model run on a monthly time step for 800 years was developed to predict the future level, areal extent and temperature of the Dead Sea under different scenarios of freshwater input and atmospheric boundary conditions. The model integrates energy, water and salt balances. The bathymetry of the Dead Sea was derived from high-resolution digital elevation data. Model results were verified against measured lake level for the period 1928 through 2022. Predicted levels are very close to observed values as demonstrated by three statistical measures. The monthly temperatures of the mixed layer as predicted by the model were also commensurate with observational results and satellite derived data. Future simulation predictions were verified against a novel diagnostic analytic method developed in this investigation. The newly developed method has the potential to approximate the equilibrium activity and temperature of hypersaline lakes under specified freshwater inflow and atmospheric forcings.Results show that the future level, areal extent and temperature of the Dead Sea will be contingent on freshwater inflow and the prevailing atmospheric forcings. Projections indicate that the Dead Sea will end up as a dwarfed hypersaline hot lake. The time span needed for the Dead Sea to reach a quasi-steady state equilibrium is several hundred years. Simulations results presented in this investigation are expected to be approximate given the complexity of the system, the long integration time involved, and uncertainties brought about by climate vagaries and model parameterizations.

Near-infrared light-induced superconducting-like state in underdoped YBa2Cu3Oy studied by c -axis terahertz third-harmonic generation

The recent observation of the light-induced superconducting (SC)-like transient response in $c$-axis optical conductivity far above the SC transition temperature ${T}_{\mathrm{c}}$ in underdoped $\mathrm{Y}{\mathrm{Ba}}_{2}{\mathrm{Cu}}_{3}{\mathrm{O}}_{y}$ (YBCO) has attracted a great deal of attention in the field of high-${T}_{\mathrm{c}}$ superconductors. Since then, various theoretical and experimental studies have been devoted to elucidating its microscopic origin. One prominent fingerprint of light-induced superconductivity is the emergence of $1/\ensuremath{\omega}$-like spectral behavior in the imaginary part of the optical conductivity in the terahertz (THz) frequency range. However, the spectral profile can also be described by the Drude response of the quasiparticles (QPs) with a substantially low scattering rate. To circumvent this critical ambiguity, we investigated the light-induced nonequilibrium state in an underdoped YBCO sample with ${T}_{\mathrm{c}}$ of 61 K using the nonlinear THz optical response originating from the SC collective excitation of the ac-driven Josephson current. Upon the near-infrared (NIR) photoexcitation above ${T}_{\mathrm{c}}$ in the YBCO sample, the $1/\ensuremath{\omega}$-like spectral behavior in the imaginary part of the optical conductivity emerges, consistent with previous studies. However, the THz third-harmonic generation arising from the ac-driven Josephson current along the $c$-axis was absent in the NIR photoexcited state. These results indicate that the NIR pump-induced state exhibiting the $1/\ensuremath{\omega}$-like response above ${T}_{\mathrm{c}}$ is distinct from the long-range-ordered SC state in equilibrium. Based on these observations, the possible origins of the irregularly coherent charge-carrier response along the $c$-axis induced by photoexcitation are discussed.

Involvement of Metabolites and Non-coding RNAs in Diseases.

Non-coding RNAs have a role in gene regulation and cellular metabolism control. Metabolism produces metabolites which are small molecules formed during the metabolic process. So far, a direct relationship between metabolites and genes is not fully established; however, pseudogenes and their progenitor genes regulate health and disease states. Other non-coding RNAs also contribute to this regulation at different cellular processes. Accumulation and depletion of metabolites accompany the dynamic equilibrium of health and disease state. In this study, metabolites, their roles in the cell, and the link between metabolites and non-coding RNAs are discussed.

Within-host models of dengue virus transmission with immune response

AbstractDengue fever is an infectious viral fever. The complex behavior of the virus within the body can be explained through mathematical models to understand the virus’s dynamics. We propose two different with-in host models of dengue virus transmission with humoral immune response. The proposed models differ from one another because one of the models assumes that newly formed viruses infect healthy cells again. To understand the dynamics of the proposed models, we perform a comparative study of stability analysis, numerical simulation, and sensitivity analysis. The basic reproduction number (BRN) of the two models is computed using next-generation matrix method. The local stability (l.s) analysis is discussed using the linearization method. The Lyapunov’s direct method is used to check the global stability (g.s) of the models. It has been found that both the equilibrium states for both the models, namely, virus-free equilibrium state and endemic equilibrium state, are globally stable, based on the value of BRN. Results show the influence of immune response on the cell dynamics and virus particles. The virus neutralization rate by antibodies and rate that affects the antibody growth are highly sensitive for the two models. Optimal control is applied to explore the possible control strategies to prevent virus spread in the host system. It is evident from the results that the strategy to administrate antibiotic drugs and home remedies slow down the virus spread in the host.

Resistance Value Analysis Study using the Wheatstone bridge circuit method and the Circuit Wizard and Proteus 8 simulators

The Wheatstone bridge circuit is one configuration resistor circuit that serves to measure changes in resistance (resistance) is very small, and has been widely used in circuits sensors. This circuit is arranged like a rhombus, at least four resistors (R1, R2, R3, R4), one of which is a resistor not fixed (R3) which usually uses a variable resistor. Then, one of them is a resistor whose resistance value is sought (R4). This study aims to explore a series of bridges Wheatstone with three scenarios. First, the search for one of the the correct value of the resistor (R4) when the state is balanced, or when the current is flow at point AB is equal to Zero (IAB = 0 A). Second, measure Wheatstone bridge voltage (VAB) with varying resistor values. Third, look for one of the resistor values (R4), the replacement resistance value of all resistance (REq) at the state of balance, and the total current flows (ITotal) in the Wheatstone bridge circuit when VAB = 0 Volts. The analysis utilizes two offline simulators, namely Circuit Wizard v.1.15 and Proteus v.8.5. Then the simulation results all three are compared with theoretical calculations. Simulation results of The three simulators prove that the current and voltage values on the Wheatstone circuit is in accordance with theoretical calculations, where IAB = 0 A and VAB = 0 V if the state is balanced. In no state equilibrium, then there will be a current flowing from point A to point B so there is a potential difference, where the value of this potential difference is the same
 with VA – VB. This article also examines the performance and trade-offs of the three simulators when experimenting with circuits Wheatstone bridge based on hands-on experience from the researcher's point of view

Electronic, optical and huge figure of merit of MnFeTe Heuslerene

Based on the density functional theory (DFT) calculations, the structural, electronic, optical and thermoelectric properties of the MnFeTe Heuslerene compound have been investigated. The total energy change curve in terms of volume refers to the ground state point and equilibrium volume. By applying mBJ approximation, this compound has perfect half-metallic behavior of 100% spin polarization at the Fermi level with 7[Formula: see text] magnetic moment. Optical calculations show that the semiconductor behavior with an optical absorption gap occurred by incident light perpendicular to the MnFeTe Heuslerene plane. The figure of merit coefficient (ZT) has reached 3.5 at 50[Formula: see text]K temperature, which makes it an excellent candidate for thermoelectric applications. Also, the power factor (PF) of this compound has reached its maximum value at room temperature.

A Lyapunov functional for vaccination model on the dynamics of cholera epidemic with non-linear incidence of infection

A new deterministic susceptible-exposed-infectious-vaccinated-removed-pathogen (SEIVRB) cholera epidemic model with combined mass action incidence and saturated incidence rates is proposed and analyzed. A threshold level of vaccine coverage necessary for controlling or eradicating cholera has been determined and analyzed using the next generation matrix approach. It is shown that the higher values of vaccine coverage that are lower than the threshold value significantly reduces the number of infected individuals whenever basic reproduction number is less than unity, and the cholera would persist in the populations whenever the model basic reproduction number exceeds unity. The global stability for cholera free equilibrium state and cholera endemic equilibrium state of the model system is investigated using Lyapunov functional approach and Lasalle invariance principle, which are found to be globally asymptotically stable at both equilibrium states. Numerical simulations and graphical illustrations is presented to support the analytical results found in the study.

"Ideal'nost'" "neideal'noy" plazmy

Two chemical models of the plasma, which describe the mixture of free electrons, ions, and atoms, are derived using identity transformations based on the equation of state of the “physical” model of the plasma, in which an interacting mixture of electrons and nuclei (protons) us considered. These chemical models satisfy Onsager’s bookkeeping rule (the equation of state is independent on the position of the bookmark, viz., the boundary separating free and bound states). The effect of excited states of an atom on the equation of state and ionization equilibrium is analyzed. It is concluded that the contribution of the Debye attraction in traditional “chemical” models is overestimated. The relations obtained for the ionization potential lowering and the equations of state differ significantly from the generally accepted expressions and explain qualitatively the experimentally observed effect of “ideality” of a nonideal plasma.

Study on the response law between cooling rate and temperature with process parameters during vacuum freezing of liquid

Vacuum freezing has high freezing efficiency, fast cooling rate, and no special cold source is required, it can be easily carried out on general vacuum freeze-drying equipment. Nevertheless, it is difficult to accurately control the freezing temperature and cooling rate during vacuum freezing on traditional freeze-drying equipment. In order to control the freezing temperature and cooling rate, the mathematical model of vacuum freezing process is established by using the basic theory of phase change heat and mass transfer and the gas state equilibrium equation. The iterative method is used to calculate and simulate the relationship between the three controllable process parameters on the general freeze-drying equipment: evaporation area, pumping speed and liquid thickness with the freezing temperature and cooling rate. The experimental results obtained using the experimental equipment are largely consistent with the theoretical results. It provides a theoretical foundation for controlling the freezing temperature and cooling rate during the vacuum freezing process.

Photophysical and photochemical properties of 3-hydroxyflavone in ethanol solution: Implicit vs explicit solvent models

Photophysical and photochemical properties of 3-hydroxyflavone in gas-phase and solution were studied using implicit (Polarizable Continuum Model, PCM) and explicit solvent (Averaged Solvent Electrostatic Potential from Molecular Dynamics calculations, ASEP/MD) models. The conformational equilibrium in the excited state between the normal (N*) and tautomeric (T*) forms and their absorption and fluorescence spectra was studied with Time-Dependent Density Functional Theory (TD-DFT) and three different functionals. The calculated transitions are in good agreement with the spectroscopic data. It was found that solvent effects on the absorption and fluorescence spectral bands are negligible. Still, they can modify appreciably the relative stability of the N* minimum with respect to the Franck-Condon position, which affects the kinetics of the reaction. This fact, together with the increase in the barrier height in protic solvents, permits us to explain the reduction of the emission signal from T* and the increase of the N* signal in ethanol solution.

Analytical population dynamics underlying harmful algal blooms triggered by prey avoidance

A modified version of the NPZD ecosystem model is used to analytically examine the effects of predation avoidance, a possible mechanism for triggering harmful algal blooms (HAB). To resolve HAB development caused by predation avoidance, an additional phytoplankton functional group is considered, one that has slower nutrient uptake and better predation avoidance characteristics than the non-harmful phytoplankton group used in traditional NPZD models. Because the two phytoplankton groups (one non-harmful and one HAB) compete for only one resource within the same system, steady state (equilibrium) conditions cannot occur without the presence of zooplankton; only the non-harmful phytoplankton group, which defeats the HAB group in the resource competition, can survive in the equilibrium. The presence of sufficient zooplankton effectively acts to replenish the nutrient pool by consuming the non-harmful phytoplankton. When this occurs, two equilibrium states are found: one with both phytoplankton groups coexisting, and one that only includes the HAB group. The condition required for equilibrium is that the total nitrogen within the system should be larger than a threshold determined by model coefficients. The threshold and feasibility of the equilibrium are sensitive to the relative HAB predation avoidance coefficient. If the coefficient is larger than the ratio of net growth rates between the HAB and non-harmful phytoplankton group, the threshold becomes infinite, and an equilibrium is not feasible. The time scale for the system to reach an equilibrium state that includes a HAB group is determined asymptotically. The dependence of a threshold condition as a controlling factor may explain the regime shift of dominant species causing HABs. The ecosystem model is fully implemented into the Regional Ocean Modeling System and applied to an idealized coastal embayment (with depths and geometry taken from San Francisco Bay) to show numerically the dominance of prey avoidance dynamics in a natural shallow water environment that includes advection and diffusion. The analytical results improve strategies for HAB modeling and provide guidance for setting model coefficients necessary to resolve a HAB event.

Solving 2D and 3D Lattice Models of Correlated Fermions—Combining Matrix Product States with Mean-Field Theory

Correlated electron states are at the root of many important phenomena including unconventional superconductivity (USC), where electron pairing arises from repulsive interactions. Computing the properties of correlated electrons, such as the critical temperature Tc for the onset of USC, efficiently and reliably from the microscopic physics with quantitative methods remains a major challenge for almost all models and materials. In this theoretical work, we combine matrix product states (MPS) with static mean field (MF) to provide a solution to this challenge for quasi-one-dimensional (Q1D) systems: two- and three-dimensional materials comprised of weakly coupled correlated 1D fermions. This MPS+MF framework for the ground state and thermal equilibrium properties of Q1D fermions is developed and validated for attractive Hubbard systems first, and further enhanced via analytical field theory. We then deploy it to compute Tc for superconductivity in 3D arrays of weakly coupled, doped, and repulsive Hubbard ladders. The MPS+MF framework thus enables the quantitative study of USC and high-Tc superconductivity—and potentially many more correlated phases—in fermionic Q1D systems based directly on their microscopic parameters, in ways inaccessible to previous methods. This approach further allows one to treat competing macroscopic orders, such as superconducting and insulating ones, on an equal footing. Benchmarks of the framework using auxiliary-field quantum Monte Carlo techniques show that the overestimation of, e.g., Tc due to its mean-field component, is near constant in microscopic parameters. These features of the MPS+MF approach to correlated fermions open up the possibility of designing deliberately optimized Q1D superconductors, from experiments in ultracold gases to synthesizing new materials.13 MoreReceived 8 July 2022Revised 7 December 2022Accepted 3 January 2023DOI:https://doi.org/10.1103/PhysRevX.13.011039Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasFermionsSuperconductivityPhysical Systems3-dimensional systemsStrongly correlated systemsUnconventional superconductorsTechniquesBosonizationDensity matrix renormalization groupMean field theoryCondensed Matter, Materials & Applied Physics

Quadripartite bond length rule applied to two prototypical aromatic and antiaromatic molecules

ContextIn 2000, a remarkably simple relationship was introduced, which connected the calculated geometries of isomolecular states of three different multiplicities. These encompass a ground single state, the first excited triplet state, as well as related radical anion and radical cation. The rule allows the prediction of the geometry of one of the species if the three remaining ones are known. Here, we verify the applicability of this bond length rule for two small planar cyclic organic molecules, i.e., benzene and cyclobutadiene, which stand as prototypical examples of, respectively, aromatic and antiaromatic systems. We see that the rule works fairly well to benzene, and it works independently for quinoid as well as for anti-quinoid minima, despite the fact that radical anion species poses challenges for correct theoretical description.MethodsTo obtain chosen electronic state equilibrium geometries, three types of computational approaches were utilized: fast and efficient density functional theory DFT, the coupled cluster method CC2, the complete active space self-consistent field (CASSCF) approach, and the most accurate but also resource-consuming perturbation theory with multireference wavefunction (CASPT2) with a default value and without IPEA-shift. Dunning and co-workers correlation-consistent basis sets (aug-)cc-pVXZ (X = D, T, Q) were employed. Gaussian 16 revision A.03, Turbomole 7.1, and Molcas 8.0 computational software were used.

Probing Oxidant Effects on Superoxide Dismutase 1 Oligomeric States in Live Cells Using Single-Molecule Fluorescence Anisotropy.

The protein Cu/Zn superoxide dismutase (SOD1) is known to function as a dimer, but its concentration in cells (∼50 μM) and the dimerization constant (K d of 500 μM) results suggest that it exists in a monomer-dimer equilibrium. It is unclear how the oligomeric state of SOD1 changes when cells are initially exposed to high levels of extracellular oxidative stress. To address this problem, we introduced the single-molecule fluorescence anisotropy (smFA) assay to explore SOD1 oligomeric states in live COS7 cells. smFA specifically probes the fluorescence polarization changes caused by molecular rotations where the fast-rotating molecules (either due to smaller hydrodynamic volume or less viscous environments) deteriorate the emission polarization and thus lower the anisotropy. After validating that smFA is effective in distinguishing monomeric and dimeric fluorescence proteins, we overexpressed SOD1 in live COS7 cells and investigated how its oligomeric state changes under basal, 2 h, and 24 h 100 μM H2O2 treatments. We found that treating cells with H2O2 promotes SOD1 dimerization and decreases cellular viscosity in 2 h. Interestingly, prolonged H2O2 treatments show similar results as the basal conditions, indicating that cells return to a steady state similar to the basal state after 24 h, despite the presence of H2O2. Our results demonstrate that SOD1 changes its oligomeric state equilibrium in response to extracellular oxidative stresses. smFA will open new opportunities to explore the relationship between the SOD1 oligomer state and its H2O2-based signaling and transcription regulation roles.

A method for calculating the void fraction of two-phase leakage ports of storage tanks

The problem of leakage of superheated liquids such as LPG, LNG, LCG and AML is widely valued in the process industry. The key to superheated liquid storage and transportation is to prevent cracks due to unexpected situations such as tank overpressure, pipe corrosion and violent collisions. When the tank wall ruptures, the air pressure inside the tank drops sharply and a violent phase change occurs in the degraded liquid inside the tank to maintain energy balance. The liquid instantly evaporates into a gas, releasing a huge amount of energy to form a flash, and this leakage can lead to violent phase changes and two-phase flash jets containing large amounts of liquid droplets and steam, and further lead to major safety accidents such as fires, explosions and the spread of toxic substances. In this work, the pressure drop in the tank during a leak and the phase change at the leak caused by the pressure change at the orifice are investigated through theoretical analysis and experiments. Based on the ideal gas equation of state, mass conservation, gas-liquid non-slip and thermodynamic equilibrium, the pressure drop inside the tank and the phase change at the orifice during the whole leakage process are modelled and validated, and the results show that the model is in good agreement.

Nuclear Equation of State for Arbitrary Proton Fraction and Temperature Based on Chiral Effective Field Theory and a Gaussian Process Emulator.

We calculate the equation of state of asymmetric nuclear matter at finite temperature based on chiral effective field theory interactions to next-to-next-to-next-to-leading order. Our results assess the theoretical uncertainties from the many-body calculation and the chiral expansion. Using a Gaussian process emulator for the free energy, we derive the thermodynamic properties of matter through consistent derivatives and use the Gaussian process to access arbitrary proton fraction and temperature. This enables a first nonparametric calculation of the equation of state in beta equilibrium, and of the speed of sound and the symmetry energy at finite temperature. Moreover, our results show that the thermal part of the pressure decreases with increasing densities.

Luminescent Lanthanide Complexes for Effective Oxygen-Sensing and Singlet Oxygen Generation.

Oxygen quantification using luminescence has attracted considerable attention in various fields, including environmental monitoring and clinical analysis. Among the reported luminophores, trivalent lanthanide complexes have displayed characteristic narrow emission bands with high brightness. This bright emission is based on photo-sensitized energy transfer via organic triplet states. The organic triplet states in lanthanide complexes effectively react with the triplet oxygen, enabling oxygen quantification by lanthanide luminescence. Some TbIII and EuIII complexes with slow deactivation processes have also formed the excited state equilibrium, thus resulting in the emission-lifetime based oxygen sensing property. The combination of TbIII /EuIII emission, EuIII /SmIII emission, EuIII /ligand phosphorescence, and ligand fluorescence/ligand phosphorescence provide the ratiometric oxygen-sensing properties. Moreover, the reaction generates singlet oxygen species which exhibit numerous applications in the photo-medical field. The ligands with large π-conjugated aromatic systems, such as porphyrin, phthalocyanine, and polyaromatic compounds, induces highly efficient oxygen generation. The combination of effective luminescence with singlet-oxygen generation by the lanthanide complexes render them suitable for photo-driven theranostics. This review summarizes the research progress of lanthanide complexes with efficient oxygen-sensing and singlet-oxygen generation properties.

Searching for the ideal glass transition: Going to yotta seconds and beyond

Here we report results for the dynamics of a 50-million-year-old (geologically) aged Fushun amber that had a fictive temperature Tfapproximately 193 K below its glass transition temperatureTg in the thermally rejuvenated state. The density of this ultra-stable amber was found to be 14% greater than the post-rejuvenation value. Length change dilatometry was used to map the Tf by performing de-aging experiments and equilibrium state dynamics were obtained by making measurements at T=Tf. Time-Temperature Superposition was applied to the frequency dependent storage and loss modulus measurements both along the equilibrium line and in upper-bound conditions where T>Tf. We find that the relaxation times cover >1027s (1 ronna second), i.e., thousands of yotta seconds but do not follow the “expected” Vogel-Fulcher-Tammann (VFT) type of super-Arrhenius type of temperature dependence. Rather the deep glassy state equilibrium dynamics show no evidence of divergence at a finite temperature for temperatures that would be expected to be far below the ideal glass temperature Tg,ideal. In addition, at constant fictive temperature, we find that the relaxation times vary very strongly with specific volume v whereas, in isothermal conditions, the relaxation times are only weakly dependent on v. These results evidence that the deep glass state behavior presents a challenge to current ideas about glasses and the glass transition.