State Of Dynamic Equilibrium Research Articles

Discrete numerical simulation of performance analysis of horizontal trough-free screw conveyor in dynamic equilibrium state

A horizontal trough–free screw conveyor can be employed to achieve the directional flow of materials on a free surface, and the material flow is complex under different operating parameters. A Discrete Element Method model was developed to study the effects of three operating parameters on the screw performance and material flow characteristics in the dynamic equilibrium state. The mass flow rate increased linearly proportional to the lowering depth, but the relationship with the translational velocity was nonlinear. The effective conveying rate decreased after the materials were thrown back over the top of the shaft. Mass of each material group was defined as a function of group 1, and the mass increase factor was quantitively calculated. The increase in the rotational velocity had insignificant effect on the increase in conveying capacity. When the velocity exceeded 360 r/min, the torque and power suddenly increased, but the mass flow rate remained largely unchanged.

The phenomenon of ecological safety as an object of axiological and legal reflection

The article substantiates the axiological and legal principles of environmental security in the modern world, clarifies the role of the value system of society in the socio-cultural mechanism of environmental security. The author formulates the definition of ecological safety as a state of constant and dynamic equilibrium of the nature-society system, characterized by, on the

Study on the Oil Film Force with Unlimited Length Oil Film of the Sliding Bearing and the ERSFD with Bosses

The research background is the elastic ring squeeze film damper. Four contact pressure models were established by analyzing the structural characteristics and movement, combined with the sliding bearing theory, including structural parameters and eccentricities. Multi-structure and multi-interval dynamic boundary conditions were selected by analyzing actual structures. Simpson, polynomial, and integrated parameters methods extended Booker formulas. By combining existences and forms of the solution and mean-value theories, approximate analytical solutions of the finite length bearing were obtained under different contacts. Combined with the short and long bearing, general structures and expressions of analytical solutions of oil film pressures and forces under three approximation theories were obtained. The oil film characteristics of the dynamic equilibrium state were obtained, and the correctness was verified by theoretical comparison. Numerical simulations analyzed the relationship among relevant parameters. It provided a theoretical basis upon which to study the geometric form, motion state, and the approximate analytical solution of the ERSFD dynamic model, and increased its research ability.

Synthesis of salicylic acid phenylethyl ester (SAPE) and its implication in immunomodulatory and anticancer roles

Salicylic acid phenylethyl ester (SAPE) was synthesized by Zn(OTf)2-catalyzed selective esterification of salicylic acid and phenylethyl alcohol and studied for its role as an immunomodulatory and anticancer agent. Low toxicity and favorable physical, Lipinski-type, and solubility properties were elucidated by ADME-tox studies. Molecular docking of SAPE against COX-2 revealed favorable MolDockscore, rerank score, interaction energy, internal pose energy, and hydrogen bonding as compared to ibuprofen and indomethacin. An average RMSD of ~ 0.13 nm for the docked complex with stable dynamic equilibrium condition was noted during the 20 ns MD simulation. A low band gap predicting a strong binding affinity at the enzyme’s active site was further predicted by DFT analysis. The ester caused a reduction in the percentage of erythrocyte hemolysis and was shown to be non-cytotoxic against human lymphocytes, CaCo-2, and HepG-2 cells by the MTT assay. Moreover, it’s in vitro efficacy in inhibiting COX-2 enzyme under both LPS stimulated intestinal cells and direct sequestration assays was found to be higher than salicylic acid and indomethacin. The anticancer activity of SAPE was tested on the breast cancer cell line MCF-7, and potential efficacy was exhibited in terms of decreased cell viability. Flow cytometry analysis exhibited the arrest of the cell cycle at G1/G0 and S phases, during which induction of autophagic vesicle formation and decrease in mitochondrial membrane potential was observed owing to increased ROS production. Furthermore, at these phases, the onset of apoptosis along with DNA damage was also observed. Pre-treatment with SAPE in colitis-induced Wistar rats displayed low disease activity index and reduction in the extent of intestinal tissue disruption and lipid peroxidation. A marked increase of anti-oxidative enzymes viz., catalase, GGT, and GST, and a decrease of pro-inflammatory cytokines IL-6 and TNF-α in the intestinal tissue extracts of the treated groups was noted. The results of this study have sufficient credence to support that the synthesised ester (SAPE) be considered as an anti-oxidative and anti-inflammatory compound with therapeutic potential for the effective management of cancer.

Fishtail Divertor and its basis surface thermal load bearing performance

Fishtail Divertor (FTD) configuration is a dynamic magnetic field divertor configuration that uses the AC coil installed on the back of the divertor target plate to realize the swing of the strike line. The most important driving force of FTD configuration design is to improve the thermal bearing performance of divertor target plate. Under FTD configuration, the maximum temperature of divertor target plate will eventually reach a dynamic equilibrium state, and it have an obvious jump at both ends of the swing area. With the increase of the swing frequency, FTD configuration can more effectively improve the thermal load bearing performance of the divertor target plate. However, if only to alleviate the steady-state heat load, the swing frequency of FTD no need to be higher than 100 Hz. FTD configuration has engineering application prospects in future fusion reactors. Under a swing distance of 10 cm and a thermal load condition of qp=100MW/m2 and λT=5mm (steady state), Triangular wave Fishtail Divertor (TFTD) swing frequency exceeds 5 Hz or Sine wave Fishtail Divertor (SFTD) swing frequency exceeds 20 Hz, the maximum temperature of target plate can be lower than 900 K. At the same conditions expect the swing frequency is 100 Hz, the maximum temperature under TFTD and SFTD can lower than 700 K and 800 K respectively.

A random displacement model of sediment transport in ice-covered alluvial channel flows.

There is a need for developing efficient models to simulate the sediment transport phenomenon in ice-covered alluvial channel flows, which is essential in enriching the theory of riverbed evolution. This study establishes a random displacement model parameterized with the time-averaged streamwise velocity U(z), the sediment settling velocity ωs(z), and the turbulent diffusion coefficient Dz(z) to calculate the suspended sediment concentration and the longitudinal dispersion coefficient for ice-covered alluvial channels. The proposed model is first validated to determine if it could be used to predict the sediment concentration profiles by comparing to limited experiments published in the literature. Results show that the simulations agree well with the measurements except for the underestimated concentration near the ice cover boundary. Once validated, the random displacement model is applied to explore the variation law of the suspended sediment concentration and the longitudinal dispersion with different sediment particle release modes. The sediment concentration and the stable value of the longitudinal dispersion coefficient for a given flow condition in the dynamic equilibrium state are not affected by the change of the particle release mode. The Fickian time required for the longitudinal dispersion coefficient converging to a constant, however, has a close relationship with the particle release mode and increases as the water depth increases.

The mechanical response of commercially pure copper under multiaxial loading at low and high strain rates

In this paper, we present the dynamic response of commercially pure copper subjected to combined tension-torsion loads representative of real case impact scenarios. Experiments were conducted both quasi statically, at a strain rate equal to 10−3 s−1, and dynamically at strain rates in the region between 500 s−1 and 1000 s−1. All high rate experiments were conducted using a novel Split Hopkinson Tension-Torsion Bar instrumented with high-speed photographic equipment. The dynamic combined loading experiments demonstrate the capability of the apparatus to generate longitudinal and torsional stress waves which are synchronised upon loading of the specimen. The presented data show that dynamic equilibrium conditions and nearly steady strain rates were achieved during the experiments. Additionally, the analyses of the loading paths show that nearly proportional strain loading was attained during testing.The measured experimental results illustrate, for the first time, the failure stress locus of the material over a wide range of stress states including pure torsion, shear-dominated combined tension-shear, tension-dominated combined tension-shear and plain tension. The quasi-static and dynamic failure envelopes are herein presented in the normal stress vs shear stress space to motivate the development of accurate and effective constitutive models. To conclude, the Drucker-Prager criterion was employed to approximate the failure loci and to assess the rate sensitivity of the material. A moderate asymmetry of the uniaxial ultimate stresses in tension and compression is predicted both at quasi-static and dynamic strain rates.

A random time-dependent noncooperative equilibrium problem

The paper deals with the random time-dependent oligopolistic market equilibrium problem. For such a problem the firms’ point of view has been analyzed in Barbagallo and Guarino Lo Bianco (Optim. Lett. 14: 2479–2493, 2020) while here the policymaker’s point of view is studied. The random dynamic optimal control equilibrium conditions are expressed by means of an inverse stochastic time-dependent variational inequality which is proved to be equivalent to a stochastic time-dependent variational inequality. Some existence and well-posedness results for optimal regulatory taxes are obtained. Moreover a numerical scheme to compute the solution to the stochastic time-dependent variational inequality is presented. Finally an example is discussed.

Evolution of the tracer in natural flows described by the state function ф(U, E, t): Analysis of the associated functions and their application to case studies

The tracers as a method of measuring and characterizing the evolution of natural flows, in addition to providing information on the dynamics (advection) and dispersion as "local" phenomena themselves, can give additional, dense information on the global conditions (far from the point of measurement) under the thermodynamic connection that is established between all the points of the system, when there is a steady-state in the channel. As has been widely studied since the second half of the last century, this condition of dynamic equilibrium (steady-state) in natural flows, for phenomena that do not present pronounced irreversibility (linear region of irreversible thermodynamics), implies a series of remarkable features that simplify the interpretation of the complex phenomena of turbulent currents, and thus of the superimposed dispersive processes. Within this approach, a state function, Φ(U, E, t), dependent on the mean flow velocity, the longitudinal dispersion coefficient, and time, is defined that describes the evolution of the tracer cloud, such that in its approximate quality of thermodynamic potential, it allows one to discover and pinpoint certain particularities of the phenomenon. In this paper, the characteristics and practical applications of these principles are explored. It also includes a heuristic analysis of the so-called direct functions rq(F) and inverse rq(F)-, auxiliary to the state function F(U,E, t), which are used for the interpretation of the centroid time, as well as the longitudinal and transverse diffusion-dispersion coefficients employing these functions were applied experimentally in the old stream of the city of Bogotá, “La Vieja”, presenting good agreement with the theoretical references. This topic is intended to provide a theoretical and practical tool to fully understand these processes, which are of great interest for the modeling and control of water pollution.

The Thermal Imbalances Recorded at the NE Rift during the 2012 Explosive Activity at the South East Cone (Mt. Etna, Italy)

Mild thermal anomalies are sensitive to change in the advection processes in a volcanic system. A mild thermal anomaly, near the top of the North-East Rift of Mt. Etna (Italy), has been monitored from January 2010 to September 2012 by means of four temperature sensors buried in the shallow ground. The pulses of the convective circulation have been tracked and the diffuse heat flux has been evaluated. The positive pulses of the convective front reflected the local increases of volcanic degassing; conversely, the negative pulses showed the contraction of the convective front emerging through the North-East Rift. The steam condensation depth fluctuated below the monitoring site, from depths of a couple of meters to more than 30 meters, while the New South-East crater was erupting. The data hourly recorded, relative to the 2012 eruptive period, were compared to the radiant energy released by the paroxysms. We registered a dramatic decrease in the diffuse heat flux several hours before the onset of the two most energetic paroxysms (12 and 23 April). Thereafter, the convective front (the steam condensation depth) showed many negative pulses, reaching the deepest recorded levels. Thermal transients could be one of the early signals, possibly heralding transitions in the dynamic equilibrium conditions.

CO2 -Promoted Direct Acylation of Amines and Phenols by the Activation of Inert Thioacid Salts.

Herein a carbon dioxide-promoted synthetic approach for the direct amidation between unactivated thioacid salts and amines under mild conditions was developed for a wide range of substrates. The method afforded amides in good to excellent yields under transition-metal-free and activation-reagent-free conditions, in sharp contrast to early methodologies on amide synthesis based on transition-metal catalysis. The method offered a greener and transition metal-free protocol applicable to pharmaceuticals preparations. Phenolic compounds were also found to be suitable acylation substrates with potassium thiosulfide KHS as the only byproduct. Moreover, this approach was applied to amide synthesis of valuable bio-active molecules such as moclobemide, melatonin, and a fungicide. Insights into the reaction mechanism involving carbon dioxide were provided through NMR spectroscopy and computational calculations. A plausible mechanism was proposed that involves weak interactions between carbon dioxide and potassium thioacetate in a dynamic equilibrium state formation of a six-membered ring.

Study of the Mechanical and Microscopic Properties of Modified Silty Clay under Freeze-Thaw Cycles

Silty clay can be found in the alpine region of the Qinghai province, China, where it is subject to annual freeze-thaw cycles. To investigate the static mechanical properties of silty clay modified by basalt fiber and basalt powder under the action of freeze-thaw cycles, triaxial compression tests and scanning electron microscope tests were conducted on the soil. The test results revealed that varying the number of freeze-thaw cycles resulted to different effects on the soil mechanical strength, which tended to increase after 2 cycles, but then tended to decline when subjected to 5–10 cycles. After 20 freeze-thaw cycles, soil strength reached a dynamic equilibrium state. The shear strength of basalt fiber soil and basalt powder soil increased by 7.55% and 5.12%, respectively, compared with that of normal soil under 30 freeze-thaw cycles. Subsequently increasing of the number of freeze-thaw cycles differentially affected the cohesion and internal friction angle of normal soil and admixture soils, and these soils gradually tended to stabilize at a mechanical strength higher than the initial value. Basalt fibers reinforced the soil to a higher degree than basalt powder at a dosage of 0.4% based on dry soil mass. The stress-strain curves of the three soil types can be simulated using the hyperbolic model. The results of the study can provide some theoretical reference for practical engineering in seasonal frozen soil areas.

Numerical Experiment on Salt Transport Mechanism of Salt Intrusion in Estuarine Area

The process of exchange and transport between salt and fresh water is affected by not only convection due to the density gradient but also turbulence. In this study, a high resolution mathematical model of the intrusion movement of saltwater in an estuary area was established and compared with a physical flume experiment. The model, whose minimum horizontal grid cell of the model is 0.05 m, and minimum vertical grid cell is 0.0005 m, simulated well the salt transport mechanism at the interface between salt and fresh water. The salt transport processes of estuarine saltwater intrusion were obtained under the conditions of no runoff and no tide, no runoff and tide, and runoff and tide. The results suggest that under the joint action of runoff and tide, the mixing process in the interface of salt and fresh water is relatively gentle, the change in the velocity gradient is small, and the advance distance of saltwater intrusion will reach a dynamic equilibrium state after a period of time.

Моделирование процессов взаимодействия микроорганизмов в кишечнике кур

The study of an integral microbial-organismal biosystem in chickens, which is in a state of dynamic equilibrium with a relatively constant taxonomic composition of the microbiome, which varies depending on feed and a number of other factors, can be determined by the ratio of individual groups of microorganisms. The work is devoted to the development of a unified fractal model that allows assessing the state of the intestinal microbiota of chickens under the influence of factors correcting microbiocenoses (probiotics, prebiotics, phytobiotics, etc.). Based on the results of metagenomic studies, fractal portraits of microbial profiles under the influence of probiotic, prebiotic and phytobiotic were built. The parameters of the Fr3 fractal model, the indices of bioconsolidation of microbial communities in the intestines of birds were calculated according to the experimental variants.

СРАВНИТЕЛЬНЫЙ АНАЛИЗ СХЕМ ОПРЕДЕЛЕНИЯ ДИНАМИЧЕСКОЙ ПРОЧНОСТИ СЛОИСТЫХ КОМПОЗИТОВ ПРИ МЕЖСЛОЙНОМ СДВИГЕ

To determine the mechanical characteristics under conditions of intense dynamic impacts of polymer composite materials during interlayer shear, three experimental schemes were proposed and tested: dynamic three-point bending of a short beam, dynamic compression of specimens-plates with notches, and dynamic extrusion of the middle part of specimens in the form of parallelepipeds. To create shock loads and record the response of the samples, the technique of measuring rods is used. The calculation of forces and displacements is carried out according to the Kolsky formulas according to the data of tensometric measurements. Using numerical simulation, one of the fundamental assumptions and conditions for the applicability of the Kolsky method for determining the characteristics of materials in an experiment on dynamic bending of a short beam, namely, the condition of dynamic equilibrium of the sample during loading, was verified. Approbation of the schemes was carried out on samples of a layered composite material with a polymer matrix reinforced with carbon fiber. A comparative analysis of the data obtained using three different test schemes is given. It is noted that the data obtained by the extrusion method are in good agreement with the data determined during dynamic compression of notched specimens. The strength characteristic, determined by the short beam bending method, turned out to be noticeably higher. It has been found that the interlaminar shear strength values determined in the dynamic range are, on average, 25% lower than the static characteristic. Of the three schemes, the most preferable is the scheme for extrusion of the middle part of the parallelepiped specimen, since, unlike beam bending, it allows you to vary and control the loading conditions, and, unlike testing notched specimens, it is symmetrical, which eliminates the appearance of bending moments in the specimen.

Three centuries of dynamics in the lowland section, induced by human impact: A sociogeomorphic approach

This study aims to analyze one of the most dynamic sections in the lower part of the Mureș River, Lipova-Arad sector. The geological and tectonic context influenced the shifts of the watercourse at both a regional scale and a local one. The channelization works have shortened the length of the channel by 1/3 of it. The flood events in the 70s and the mining activity have also influenced the evolution of the river in last decades. Accelerating the geomorphological processes, mostly after the great floods, have narrowed the channel by 35%, and have reduced the total islands surface by almost 80%. In this context, the Mureș River try to reach the dynamic equilibrium state had before the human interventions. Under the anthropic pressure the geomorphological processes have been accelerated and the landscape left behind in Lipova-Arad section, along the Mureș River suffered important changes.

Refining of Particulates at Stimuli‐Responsive Interfaces: Label‐Free Sorting and Isolation

AbstractThe mechanism of separation methods, for example, liquid chromatography, is realized through rapid multiple adsorption‐desorption steps leading to the dynamic equilibrium state in a mixture of molecules with different partition coefficients. Sorting of colloidal particles, including protein complexes, cells, and viruses, is limited due to a high energy barrier, up to millions kT, required to detach particles from the interface, which is in dramatic contrast to a few kT for small molecules. Such a strong interaction renders particle adsorption quasi‐irreversible. The dynamic adsorption‐desorption equilibrium is approached very slowly, if ever attainable. This limitation is alleviated with a local oscillating repulsive mechanical force generated at the microstructured stimuli‐responsive polymer interface to switch between adsorption and mechanical‐force‐facilitated desorption of the particles. Such a dynamic regime enables the separation of colloidal mixtures based on the particle‐polymer interface affinity, and it could find use in research, diagnostics, and industrial‐scale label‐free sorting of highly asymmetric mixtures of colloids and cells.

Refining of Particulates at Stimuli-Responsive Interfaces: Label-Free Sorting and Isolation.

The mechanism of separation methods, for example, liquid chromatography, is realized through rapid multiple adsorption-desorption steps leading to the dynamic equilibrium state in a mixture of molecules with different partition coefficients. Sorting of colloidal particles, including protein complexes, cells, and viruses, is limited due to a high energy barrier, up to millions kT, required to detach particles from the interface, which is in dramatic contrast to a few kT for small molecules. Such a strong interaction renders particle adsorption quasi-irreversible. The dynamic adsorption-desorption equilibrium is approached very slowly, if ever attainable. This limitation is alleviated with a local oscillating repulsive mechanical force generated at the microstructured stimuli-responsive polymer interface to switch between adsorption and mechanical-force-facilitated desorption of the particles. Such a dynamic regime enables the separation of colloidal mixtures based on the particle-polymer interface affinity, and it could find use in research, diagnostics, and industrial-scale label-free sorting of highly asymmetric mixtures of colloids and cells.

Music Listening and Homeostatic Regulation: Surviving and Flourishing in a Sonic World.

This paper argues for a biological conception of music listening as an evolutionary achievement that is related to a long history of cognitive and affective-emotional functions, which are grounded in basic homeostatic regulation. Starting from the three levels of description, the acoustic description of sounds, the neurological level of processing, and the psychological correlates of neural stimulation, it conceives of listeners as open systems that are in continuous interaction with the sonic world. By monitoring and altering their current state, they can try to stay within the limits of operating set points in the pursuit of a controlled state of dynamic equilibrium, which is fueled by interoceptive and exteroceptive sources of information. Listening, in this homeostatic view, can be adaptive and goal-directed with the aim of maintaining the internal physiology and directing behavior towards conditions that make it possible to thrive by seeking out stimuli that are valued as beneficial and worthy, or by attempting to avoid those that are annoying and harmful. This calls forth the mechanisms of pleasure and reward, the distinction between pleasure and enjoyment, the twin notions of valence and arousal, the affect-related consequences of music listening, the role of affective regulation and visceral reactions to the sounds, and the distinction between adaptive and maladaptive listening.

Analisis Temperatur Pada Proses Extruding Pelet Apung

Extruder is a device that consists of a screw (a type of pressure screw), the thread functions as a propulsion and presses the raw material so that it turns into a semi-solid material. The material is pushed and pressed out through a confined hole (die) at the thread end. The heater gives heat to the material being extruded which is called hot extrusion. The cutting knife is used to even out the size of the extruded cut, and the main feature of the extrusion process is its continuous nature. The extruder is operated under conditions of dynamic equilibrium, that is, the input equals the output, the incoming material is equivalent to the product.