State Of Dynamic Equilibrium Research Articles

Room temperature self-healable epoxy elastomer with reversible alkoxyamines as crosslinkages

To provide room temperature self-healing ability to crosslinked epoxy elastomer, alkoxyamine-based diglycidyl ether (DiEPO) is synthesized and cured with polythiol. The C–ON bonds in both the alkoxyamine monomer and the cured epoxy are able to be synchronously cleft and recombined, achieving a dynamic reversible equilibrium state. This habit can thus be used as a healing chemistry for repeatedly re-bonding cracked polymer. Moreover, because the nitrile group that possesses strong capability of adsorbing electrons is attached to the carbon atom of C–ON bonds, homolysis temperature of the alkoxyamine is greatly reduced. The reversible reaction becomes oxygen insensitive in the meantime. As a result, multiple self-healing of the epoxy elastomer in air without manual intervention (heating) is observed by visual inspection and tensile test. Compared to the self-healing crosslinked polymers containing alkoxyamine moieties, which were previously developed in our lab and had to operate at elevated temperature in argon, the current work represents an interesting progress towards practical application in this aspect.

The geomorphology of UK estuaries: The role of geological controls, antecedent conditions and human activities

This paper provides an overview of the geomorphological characteristics of UK estuaries and the factors which control them. Many of the features included in previous classifications of UK estuaries are not true estuaries since they do not possess significant river influence. The features considered in this paper to be ‘true’ estuaries are divided into ‘restricted entrance’ and ‘unrestricted entrance’ types on the grounds that the size and geometry of the estuary mouth exerts a critical influence on water levels, tidal currents, wave action, sediment transport and morphological evolution. An estuary which has a wide mouth, narrows and becomes shallower towards the head is likely to be flood dominated, especially if it has a large tidal range, whereas an estuary which has a narrow mouth and widens and/or becomes deeper towards the head is more likely to display ebb dominance, especially if it has a relatively small tidal range. Wide-mouthed estuaries are influenced to a greater degree by wave processes than estuaries with a narrow mouth. Previous authors have hypothesised that estuaries may maintain a state of dynamic equilibrium through alternating periods of flood and ebb dominance, but it is concluded that there is presently no substantive evidence to support this hypothesis. UK estuaries have been affected to varying degrees by embanking, land claim, dredging, sea wall breaching and managed realignment. Some estuaries have adjusted quickly to such perturbations, but others continue to show progressive change, either sedimentary infilling or erosion and sediment loss. The quantification of estuary morphometry, identification of change over time, and testing of hypotheses regarding the morphodynamics and stability of estuaries requires adequate bathymetric/topographic, hydrodynamic and sediment data. At present, such data are available for relatively few UK estuaries.

Shafting coupled vibration research based on wave approach

Because of propeller hydrodynamic influence, the shafting vibration is a coupled vibration which includes torsional, longitudinal and whirling vibrations. It is unsuitable to analyze different vibrations of propulsive shafting systems with development of shipbuilding technologies. To overcome the shortages of traditional marine standards, we establish a new numerical model of the shafting coupled vibration. And we put forward shafting coupled vibration calculation to ensure better reliability of main propulsion system. The shafting system is modeled into two sub-systems, a continuous one and a discrete one. Wave approach and transit matrix method are used to investigate displacement and stress fields in continuous and discrete sub-systems, respectively. And vibrations of different modes in both sub-systems are coupled by using dynamic equilibrium and continuity condition to deduce the global equations governing the motion of shafting. The coupling calculation is then used to research the reason of a very large crude carrier (VLCC) stern hull vibration. It is shown by the comparison of the results from both coupling and dependent vibration calculations that vibration in deferent directions will cause deformation in the same mode, which leads to extra stress and displacements on shafting, especially as the resonant frequencies of different vibration modes match each other. This is helpful to prevent ship stern vibration due to poor shafting vibration calculation.

A data driven method for estimation of Bavail and appKD using a single injection protocol with [11C]raclopride in the mouse

PurposeThe partial saturation approach (PSA) is a simple, single injection experimental protocol that will estimate both Bavail and appKD without the use of blood sampling. This makes it ideal for use in longitudinal studies of neurodegenerative diseases in the rodent. The aim of this study was to increase the range and applicability of the PSA by developing a data driven strategy for determining reliable regional estimates of receptor density (Bavail) and in vivo affinity (1/appKD), and validate the strategy using a simulation model. MethodsThe data driven method uses a time window guided by the dynamic equilibrium state of the system as opposed to using a static time window. To test the method, simulations of partial saturation experiments were generated and validated against experimental data. The experimental conditions simulated included a range of receptor occupancy levels and three different Bavail and appKD values to mimic diseases states. Also the effect of using a reference region and typical PET noise on the stability and accuracy of the estimates was investigated. ResultsThe investigations showed that the parameter estimates in a simulated healthy mouse, using the data driven method were within 10±30% of the simulated input for the range of occupancy levels simulated. Throughout all experimental conditions simulated, the accuracy and robustness of the estimates using the data driven method were much improved upon the typical method of using a static time window, especially at low receptor occupancy levels. Introducing a reference region caused a bias of approximately 10% over the range of occupancy levels. ConclusionsBased on extensive simulated experimental conditions, it was shown the data driven method provides accurate and precise estimates of Bavail and appKD for a broader range of conditions compared to the original method.

CD4 T Cell-autonomous TNF receptor type 2 promotes interleukin-2 transcription (IRM6P.723)

Abstract Interleukin (IL)-2 plays a key role in adjusting the dynamic state of equilibrium between effector T cells (Teffs) and regulatory T cells (Tregs) as well as channeling the outcome of immune responses. IL-2 is mainly produced by activated CD4 T cells and the absence of IL-2 signaling results in lethal autoimmunity. In this study we investigated the role of tumor necrosis factor alpha (TNF) receptors type 1 (TNFR1) and type 2 (TNFR2) on the regulation of IL-2 at the level of transcription during the primary activation of CD4 T cells. We generated TNFR1- and/or TNFR2-deficient-IL-2-GFF knock-in reporter mice to examine Il2 promoter activity at the single cell level. We found that the deficiency of TNFR2, but not TNFR1, markedly diminished the number of CD4 T cells that produced IL-2. We further correlated decreased Il2 transcription with impaired intracellular c-Rel expression in TNFR2 KO CD4 T cells. IL-2 production was augmented in response to the addition of soluble TNF implicating a role for transmembrane TNF (tmTNF). Collectively, these data suggest that CD4 T cell autonomous tmTNF/TNFR2 signaling contributes to the number of IL-2 producers by providing a critical third signal necessary for threshold Il2 promoter activity. These results have important implications for understanding the contribution of IL-2 signaling on the dynamic equilibrium between Teff cells and Treg cells and the outcome of inflammatory immune responses.

Persistent barrage firing in cortical interneurons can be induced in vivo and may be important for the suppression of epileptiform activity

Neural circuits are typically maintained in a state of dynamic equilibrium by balanced synaptic excitation and inhibition. However, brain regions that are particularly susceptible to epilepsy may have evolved additional specialized mechanisms for inhibiting over-excitation. Here we identify one such possible mechanism in the cerebral cortex and hippocampus of mice. Recently it was reported that some types of GABAergic interneurons can slowly integrate excitatory inputs until eventually they fire persistently in the absence of the original stimulus. This property, called persistent firing or retroaxonal barrage firing (BF), is of unknown physiological importance. We show that two common types of interneurons in cortical regions, neurogliaform (NG) cells and fast-spiking (FS) cells, are unique in exhibiting BF in acute slices (~85 and ~23% success rate for induction, respectively). BF can also be induced in vivo, although the success rate for induction is lower (~60% in NG cells). In slices, BF could reliably be triggered by trains of excitatory synaptic input, as well as by exposure to proconvulsant bath solutions (elevated extracellular K+, blockade of GABAA receptors). Using pair recordings in slices, we confirmed that barrage-firing NG cells can produce synaptic inhibition of nearby pyramidal neurons, and that this inhibition outlasts the original excitation. The ubiquity of NG and FS cells, together with their ability to fire persistently following excessive excitation, suggests that these interneurons may function as cortical sentinels, imposing an activity-dependent brake on undesirable neuronal hyperexcitability.

A Control Strategy Combining Adaptive Fuzzy Control and Dynamic Equilibrium State Theory for Acrobots with System Uncertainty

A Control Strategy Combining Adaptive Fuzzy Control and Dynamic Equilibrium State Theory for Acrobots with System Uncertainty

Graphene Edges Dictate the Morphology of Nanoparticles during Catalytic Channeling

We perform in-situ transmission electron microscopy (TEM) experiments of silver nanoparticles channeling on mono-, bi-, and few-layer graphene and discover that the interactions in the one-dimensional particle–graphene contact line are sufficiently strong so as to dictate the three-dimensional shape of the nanoparticles. We find a characteristic faceted shape in particles channeling along graphene ⟨100⟩ directions that is lost during turning and thus represents a dynamic equilibrium state of the graphene–particle system. We propose a model for the mechanism of zigzag edge formation and an explanation of the rate-limiting step for this process, supported by density functional theory (DFT) calculations, and obtain a good agreement between the DFT-predicted and experimentally obtained activation energies of 0.39 and 0.56 eV, respectively. Understanding the origin of the channels' orientation and the strong influence of the graphene lattice on the dynamic behavior of the particle morphology could be crucial f...

Dynamic and thermodynamic stability of relativistic, perfect fluid stars

We consider perfect fluid bodies (‘stars’) in general relativity, with the local state of the fluid specified by its 4-velocity, ua, its ‘particle number density’, n, and its ‘entropy per particle’, s. A star is said to be in dynamic equilibrium if it is a stationary, axisymmetric solution to the Einstein-fluid equations with circular flow. A star is said to be in thermodynamic equilibrium if it is in dynamic equilibrium and its total entropy, S, is an extremum for all variations of initial data that satisfy the Einstein constraint equations and have fixed total mass, M, particle number, N, and angular momentum, J. We prove that for a star in dynamic equilibrium, the necessary and sufficient condition for thermodynamic equilibrium is constancy of angular velocity, Ω, redshifted temperature, , and redshifted chemical potential, . A star in dynamic equilibrium is said to be linearly dynamically stable if all physical, gauge invariant quantities associated with linear perturbations of the star remain bounded in time; it is said to be mode stable if there are no exponentially growing solutions that are not pure gauge. A star in thermodynamic equilibrium is said to be linearly thermodynamically stable if δ2S < 0 for all variations at fixed M, N, and J; equivalently, a star in thermodynamic equilibrium is linearly thermodynamically stable if for all variations that, to first order, satisfy δM = δN = δJ = 0 (and, hence, δS = 0). Friedman previously identified positivity of canonical energy, , as a criterion for dynamic stability and argued that all rotating stars are dynamically unstable to sufficiently non-axisymmetric perturbations (the CFS instability), so our main focus is on axisymmetric stability (although we develop our formalism and prove many results for non-axisymmetric perturbations as well). We show that for a star in dynamic equilibrium, mode stability holds with respect to all axisymmetric perturbations if is positive on a certain subspace, , of axisymmetric Lagrangian perturbations that, in particular, have vanishing Lagrangian change in angular momentum density. Conversely, if fails to be positive on , then there exist perturbations that cannot become asymptotically stationary at late times. We further show that for a star in thermodynamic equilibrium, for all Lagrangian perturbations, we have , where denotes the ‘canonical energy in the rotating frame’, so positivity of for perturbations with δJ = 0 is a necessary condition for thermodynamic stability. For axisymmetric perturbations, we have , so a necessary condition for thermodynamic stability with respect to axisymmetric perturbations is positivity of on all perturbations with δJ = 0, not merely on the perturbations in . Many of our results are in close parallel with the results of Hollands and Wald for the theory of black holes.

Membrane Phosphoinositide Turnover by Voltage Sensing Phosphatases

The PI levels can be controlled by the state of dynamic equilibrium between lipid kinase-induced phosphorylation and lipid phosphatase-induced dephosphorylation. The voltage sensing phosphatases (VSPs) gain enzymatic activity upon membrane depolarization so they can trigger temporary imbalance of PIs by electrophysiological method. Recent studies reported that VSPs have both 3- and 5- phosphatase activities upon membrane depolarization. However, its enzymatic characteristics and mechanism are still unclear. Here we examined the functional role of Dr-VSP and Ci-VSP fused with PTEN (Ci-VSPTEN) in the PI turnover through Fluorescence Resonance Energy Transfer (FRET) using Pleckstrin Homology (PH) domains. VSP-induced turnover of diverse PIs, such as PI(3,4)P2, PI(4,5)P2 and PI(3,4,5)P3 showed different kinetics in degradation and resynthesis. When the Dr-VSP expressing cells were given with a 120 mV/3 s of depolarization, the level of PI(4,5)P2, indicated by PH(PLCδ) FRET fairs, decreased rapidly (τ = 1.18 ± 0.17 sec), while the levels of PI(3,4)P2 and PI(3,4,5)P3, indicated by PH(Akt), decreased slowly (τ = 1.36 ± 0.07 sec) and incompletely. The voltage dependent enzymatic activity of phosphatases was also investigated by addressing ramp depolarization which increases from 0 mV to 120 mV for 20 s (holding potential = −80 mV). PH(PLCδ) FRET started to decrease from the voltage of 33.0 ± 6.9 mV, whereas PH(Akt) FRET began to decrease from 71.0 ± 11 mV. In addition, recovery of PI(4,5)P2 and PI(3,4)P2 /PI(3,4,5)P3 showed distinct phenomena in time constants (τrcv = 7.17 ± 1.46 sec and 57.46 ± 4.78 sec, respectively) and in absolute quantity (92.3 ± 8.0 % and 55.3 ± 2.4 %, respectively). Thus, our results suggest that VSP can act as a dual phosphatase and deplete PIs with different time constants. The data also provide the molecular properties of endogenous PI re-synthesis in living cells.

Modeling the distribution of liquid between the flow core and film in adiabatic annular two-phase flows

The numerical simulation of adiabatic steam-water flow performed using the droplet entrainment model developed by the authors reflects the experimentally observed regularities of liquid flow rate variation in the film over the channel length. A procedure of calculating the fraction of entrained liquid is proposed for the conditions of dynamic equilibrium between the droplet entrainment and deposition processes. The results from application of the proposed procedure are consistent with the available experimental data.

Almighty, the Universe

Centre; size; shape; age and Creator of the Universe are some of the most basic questions puzzling the humankind since times immemorial. The direction of the time dimension is uncertain. The quest for the basic constituent of the Universe is still on. No theory is able to explain Its governance mechanism. Through this article, a truthful effort made to put together the Universal laws, which govern the functioning of the Universe. It, not even Its smallest constituent, can neither be created nor destroyed. It has created Itself in a state of dynamic equilibrium. Life span and all Its dimensions range from minus infinity to plus infinity. It's every constituent is always unique and has lived in it. Physical forces, as well as the Soul, the Desire, the Love and the Need forces, have exerted pressure to ‎continuously amend the future.‎ Summing up, God is Universe and the Universe is God‎‎.

A Variational Approach to Dynamic Recrystallization Using Probability Distributions

AbstractWe investigate a model of dynamic recrystallization in polycrystalline materials. A probability distribution function is introduced to characterize the state of individual grains by grain size and dislocation density. Specifying free energy and dissipation within the polycrystalline aggregate we are able to derive an evolution equation for the probability density function via a thermodynamic extremum principle. Once the distribution function is known macroscopic quantities like average strain and stress can be calculated. For distribution functions which are constant in time, describing a state of dynamic equilibrium, we obtain a partial differential equation in parameter space which we solve using a marching algorithm. Numerical results are presented and their physical interpretation is given. (© 2013 Wiley‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)

First-principles study of water activation on Cu-ZnO catalysts

Although many water-related catalytic reactions on Cu-ZnO catalysts, such as methanol steam reforming and water gas shift, have been extensively investigated, little is known about water dissociation on Cu-ZnO catalysts. To reveal the active center for water dissociation on Cu-ZnO catalysts, we performed density functional theory calculations on various domains of Cu-ZnO catalysts, including Cu surfaces, supported ZnO films, and Cu-ZnO interfaces. It is found that water dissociation is hindered by a relatively large energy barrier on both the planar and the stepped Cu surfaces. On supported ZnO films, the barrier of water dissociation is significantly lowered compared with the Cu surfaces and the reaction is essentially thermo-neutral, thus the dissociation reaction will easily reach a state of dynamic equilibrium and dissociative and molecular water can coexist on the film. At the Cu-ZnO interface, water dissociation is exothermic and proceeds essentially without an energy barrier. The enhanced activity of the Cu-ZnO interface is due to the strong adsorption of both the H atom and hydroxyl group, and the step-like structure at the interface. The low energy barrier of hydroxyl diffusion and water-assisted hydrogen diffusion on ZnO films allows water dissociation to occur continuously at the interface. This work highlights the unique role of the Cu-ZnO interface in water dissociation on Cu-ZnO catalysts.

Study on Tension Model of Running Deviation for Strip Rolling

For running deviation of strip and camber deviation, a tension model was established on the discussion of the dynamic equilibrium state under tension. The friction difference of strips sides or workpiece wedge causes plain rolling camber, meanwhile housings elasticity inequality or roll tilt leads to axial shifting and camber deviation. In the digital simulation, the tension-drawing model is necessary to realize tension self-adjusting, and in the production, tension increments can be calculated for adjusting the two sides gaps.

Improving Clinical Conditions by Enlarging Tumor Dormant State Based on Design Equilibrium State by Lyapunov Stability Theorem

In this study, a novel method is proposed in which designs equilibrium point of tumor model in order to decrease the density of tumor cells as well as makes the possibility of controlling desirable clinical situation to improve desirable clinical conditions by enlarging tumor dormant state. The tumor dormancy means that all tumor cells are in cell-cycle arrest or a dynamic equilibrium state in which cells proliferation are in balance with cells undergoing apoptosis and the tumor growth is blocked. Therefore, this equilibrium represents a desirable clinical condition. If the trajectories of the describing dynamic systems belong to a specific region denoted by domain of attraction, then the convergence of system to the healthy steady state is guaranteed for this equilibrium point, the domain of attraction is a set of desired clinical conditions. This problem is indicated in form of the two layer global multi objective function optimization.

OBSERVATIONS ON THE BIOLOGY OF ORGANIC ORCHARD SOILS

Three studies were used to evaluate the biology of organic orchard soils. The work focused on the three phases of organic systems: development, dynamic equilibrium and senescence. The first study consisted of a comparative analysis of the vertical distribution of nematodes, ciliates, flagellates, amoebae and endomycorrhizae associated with four pairs of mature organic and conventional cherry orchards. The second study investigated the dynamics of nematode community structure associated with transitioning a corn-soybean site into a certified organic apple orchard. In the third study, the soil biology of the new organic apple orchard was compared with the soil biology of an organic vegetable site that had been certified for 20 years, a neighboring conventional corn-soybean field with similar soil physical characteristics, and an old field secondary succession site at the Michigan State University, Kellogg Biological Station, Long Term Ecological Research project. Absolute population densities of bacterial feeding nematodes, ciliates, flagellates, amoebae and endomycorrhizae were significantly higher in the O-horizon in all eight cherry orchards, compared with the population densities at 0-15 or 15-30 cm soil depth. The O-horizon of organic orchards had significantly higher absolute population densities of flagellates and total soil-borne organisms compared with soil from the conventional orchards. In general, soil biological diversity was greater in the organic orchards than in the conventional orchards. During the apple orchard organic transition process, the relative population density of herbivorous nematodes declined. The data indicate that the soil biology of the new organic apple orchard took seven years to reach a state of dynamic equilibrium.

A multiple-vehicle type reactive dynamic user equilibrium model and algorithm with physical queues

Abstract A multiple-vehicle type reactive dynamic user equilibrium model with physical queues is presented. The single-vehicle type cumulative flow given by Newell is extended into multiple-vehicle types. The flow conditions for multiple-vehicle types on link can be divided into two classes: Class 1 is a congested condition – various types of vehicles cannot overtake; Class 2 is an uncongested condition – each type of vehicles can run according to each type of free-flow velocity. Further, multiple-vehicle type reactive dynamic user equilibrium condition is described. Finally, one iterative algorithm is proposed, and the results show that the model can demonstrate multiple-vehicle type physical queue conditions among the links and multiple-vehicle type reactive dynamic user equilibrium condition.

Modeling User Equilibrium in Microscopic Transportation Simulation

User equilibrium refers to the network-wide state where individual travelers cannot gain improvement by unilaterally changing their behaviors. The Wardropian Equilibrium has been the focus of a transportation equilibrium study. This paper modifies the dynamic traffic assignment method through utilizing the TRANSIMS system to reach the dynamic user equilibrium state in a microscopic model. The focus of research is developing three heuristics in a Routing-Microsimulation-Equilibrating order for reaching system-wide equilibrium while simultaneously minimizing the computing burden and execution. The heuristics are implemented to a TRANSIMS model to simulate a subarea of Houston, TX.

Bounded autonomy and behavioral ethics: Deonance and reactance as competing motives

We analyze business behavioral ethics in terms of bounded autonomy, namely the result of tensions between the countervailing motivations of reactance (tendencies that involve the freedom of behaving in certain ways as a right) versus deonance (tendencies that involve the appropriateness of behaving in certain ways as an obligation). We focus in particular on how the resolution of such tensions (i.e. establishment of a boundary between rights and duties—“free” behaviors versus “non-free” behaviors—in a state of dynamic equilibrium) can cause behavior to be seen as ethical by the person performing the behavior (the actor), but seen as unethical by impartial observers. That discrepancy comes from the actor’s assessment of the behavior in question as having either an inherent status (the type of behavior it is) or an instrumental status (what it does). This analysis leads us to a discussion of the following four types of situations involving unethical behavior: freedom expansion based on a behavior’s inherent status or on its instrumental status; and freedom contraction based on a behavior’s inherent status or on its instrumental status. We outline propositions consistent with those distinctions and conclude with theoretical implications.