Strong External Force Research Articles

Eyring equation and fluctuation-dissipation far away from equilibrium.

Understanding and managing the influence that either external forces or non-equilibrated environments may have on chemical processes is essential for the current and future development of theoretical chemistry. One of the central questions to solve is how to generalize the transition state theory in order to make it applicable in far from equilibrium situations. In this sense, here we propose a way to generalize Eyring's equation based on the definition of an effective thermal energy (temperature) emerging from the coupling of both fast and slow dynamic variables analyzed within the generalized Langevin dynamics scheme. This coupling makes the energy distribution of the fast degrees of freedom not equilibrate because they have been enslaved to the dynamics of the corresponding slow degrees. However, the introduction of the effective thermal energy enables us to restore an effective adiabatic separation of timescales leading to a renormalization of the generalized fluctuation-dissipation theorem. Hence, this procedure opens the possibility to deal with systems far away from equilibrium. A significant consequence of our results is that Eyring's equation is generalized to treat systems under the influence of strong external forces.

Robot Path Planning Method Based on Level Set

For the problem of robot path planning under the action of external force field, the directionality of outward force can promote and hinder the movement of the robot. The continuous path planning method can break through the traditional robot path planning algorithm based on grid search. Limit, effectively utilize the external force field existing in the space, and improve the numerical implementation method to ensure the feasibility of the planned path in the strong external force field. Based on the Level Set method, the path planning problem is defined. The particle tracking of the robot is transformed into the numerical evolution of the curve. The optimal time path is obtained by solving the Hamilton-Jacques equation. The numerical calculation accuracy of the improved backward path tracking is guaranteed. The feasibility of planning the path. The simulation results show that the algorithm can effectively deal with a variety of complex external force fields and maintain the path in a strong external force field.

Nanoengineering of transparent polypropylene containing sorbitol-based clarifier

In this work, 1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl) methylene]-nonitol (TBPMN) was conscripted as the clarifying agent, the influence of the injection pressure on optical properties of PP were investigated, and results documented that increasing the injection pressure could not improve the transparency of the transparent PP. Thereafter, the crystallization behavior and morphological changes of transparent PP in condensed structure under different injection pressures were studied by the differential scanning calorimetry (DSC), the scanning electron microscopy (SEM) and the dynamic thermomechanical analysis (DMA), respectively, and results presented that change in injection pressure influence crystallization properties significantly. Besed on analyzing of the relationship between structure and optical properties, the effect of pressure on the optical properties was explained as follows: low injection pressure would be facilitated to the transparency of transparent PP, because under low injection pressure, the clarifier fiber could be dispersed uniformly and the network structure was formed and preserved well, and molecular chains of transparent PP was crystallized to the nanometer-level fiber on the surface of nucleation sites, which greatly reduces the scattering of light. However, increasing the injection pressure would promote the fiber itself accumulation into a scatterer point, which not only reduces the effect of the clarifier, but also causes the preferential arrangement of the PP molecules to produce an oriented structure due to strong external force and shearing action, thereby increasing light scattering.

Natto Intake is Inversely Associated with Osteoporotic Fracture Risk in Postmenopausal Japanese Women

Background:The direct association between intake of Japanese fermented soybeans, namely natto, and bone mineral density (BMD) is known. However, the association with osteoporotic fractures has not been studied. Objectives:This study aimed to investigate whether habitual natto intake is associated with a risk of osteoporotic fractures. Methods:This prospective cohort study included 1417 postmenopausal Japanese women who were enrolled in the Japanese Population-Based Osteoporosis cohort study in 1996, 1999, 2002, and 2006 and were aged ≥45 y at baseline. The intake of natto, tofu, and other soybean products was surveyed with use of a FFQ at baseline. Fractures were ascertained in follow-up surveys conducted in 1999, 2002, 2006, and 2011/2012. Osteoporotic fracture was the primary outcome and was defined as a clinical fracture occurring without strong external force, diagnosed with radiographs by a medical doctor. HRs with 95% CIs were estimated with Cox proportional hazard models. Results:During the 17,699 person-years of follow-up (median, 15.2 y), 172 women experienced osteoporotic fractures. After adjustment for age and BMD at the total hip, the HRs compared with those of <1 pack (approximately 40g)/wk natto intake were 0.72 (95% CI: 0.52, 0.98) and 0.51 (95% CI: 0.30, 0.87) for 1–6 and ≥7 packs/wk, respectively. After further adjustment for BMI, history of osteoporotic fractures, history of myocardial infarction or stroke, diabetes mellitus, current smoking, alcohol intake, frequency of tofu and other soybean product intakes, and dietary calcium intake, the HRs were 0.79 (95% CI: 0.56, 1.10) and 0.56 (95% CI: 0.32, 0.99) for 1–6 and ≥7 packs/wk, respectively. Frequency of tofu or other soybean product intakes had no association with the risk of osteoporotic fractures. Conclusions:Habitual natto intake may be associated with a reduced risk of osteoporotic fractures independent of confounding factors, including BMD, in Japanese postmenopausal women. This trial was registered at umin.ac.jp as UMIN 000032869

An unusual impalement injury to knee

Impalement injuries are one of the severe types of injuries combining effects of both penetrating and blunt trauma leading to crushing injury, wound contamination, and multi-organ damage. These types of injuries are usually a result of falls from a height, vehicular accidents, and slip with strong external force. A 12-year-old boy was involved in a road traffic accident where an auto-rickshaw toppled. A loose rusted iron frame penetrated through his left knee and lower thigh. The impaled rod was removed under direct vision and the fractured lateral femoral condyle was fixed under general anesthesia. Impalement injuries require a multidisciplinary approach. The management of each case has to be individualized. Extensive wound exposure, extraction under direct vision, adequate debridement, and antibiotic coverage are pearls of management.

The breakdown of the local thermal equilibrium approximation for a polymer chain during packaging.

The conformational relaxation of a polymer chain often slows down in various biological and engineering processes. The polymer, then, may stay in nonequilibrium states throughout the process such that one may not invoke the local thermal equilibrium (LTE) approximation, which has been usually employed to describe the kinetics of various processes. In this work, motivated by recent single-molecule experiments on DNA packaging into a viral capsid, we investigate how the nonequilibrium conformations and the LTE approximation would affect the packaging of a polymer chain into small confinement. We employ a simple but generic coarse-grained model and Langevin dynamics simulations to investigate the packaging kinetics. The polymer segments (both inside and outside the confinement) stay away from equilibrium under strong external force. We devise a simulation scheme to invoke the LTE approximation during packaging and find that the relaxation of nonequilibrium conformations plays a critical role in regulating the packaging rate.

Time-dependent active microrheology in dilute colloidal suspensions

In a microrheological set-up a single probe particle immersed in a complex fluid is exposed to a strong external force driving the system out of equilibrium. Here, we elaborate analytically the time-dependent response of a probe particle in a dilute suspension of Brownian particles to a large step-force, exact in first order of the density of the bath particles. The time-dependent drift velocity approaches its stationary state value exponentially fast for arbitrarily small driving in striking contrast to the power-law prediction of linear response encoded in the long-time tails of the velocity autocorrelation function. We show that the stationary-state behavior depends nonanalytically on the driving force and connect this behavior to the persistent correlations in the equilibrium state. We argue that this relation holds generically. Furthermore, we elaborate that the fluctuations in the direction of the force display transient superdiffusive behavior.

Shape and Stability of a Pendant Nanodrop.

The shape and stability of a pendant nanodrop attached to a smooth or rough solid surface are considered on the basis of the microscopic density functional theory in the presence of a strong external force normal to the solid surface. The drop profile, width, and height of the drop and the contact angle that a nanodrop makes with the solid surface are calculated and some interesting features of the drop shape and stability are identified. In particular, a linear relationship between the height of the drop and the contact angle, as well as one between the critical external force at which the drop loses its stability and the strength of the fluid-solid interaction, was found. In some cases, a fixed point on the drop profile was observed whose spacial location does not depend on the value of external force. It is also argued that the Bond number that is a characteristic of the pendant macroscopic drop is not applicable to nanodrops.

High-frequency forced oscillations in neuronlike elements.

We analyzed a generic relaxation oscillator under moderately strong forcing at a frequency much greater that the natural intrinsic frequency of the oscillator. Additionally, the forcing is of the same sign and, thus, has a nonzero average, matching neuroscience applications. We found that, first, the transition to high-frequency synchronous oscillations occurs mostly through periodic solutions with virtually no chaotic regimes present. Second, the amplitude of the high-frequency oscillations is large, suggesting an important role for these oscillations in applications. Third, the 1:1 synchronized solution may lose stability, and, contrary to other cases, this occurs at smaller, but not at higher frequency differences between intrinsic and forcing oscillations. We analytically built a map that gives an explanation of these properties. Thus, we found a way to substantially "overclock" the oscillator with only a moderately strong external force. Interestingly, in application to neuroscience, both excitatory and inhibitory inputs can force the high-frequency oscillations.

Analysis of microseismicity associated with the 2017 seismic swarm near the Aegean coast of NW Turkey

A thorough spatiotemporal analysis of the intense seismic activity that took place near the Aegean coast of NW Turkey during January–March 2017 was conducted, aiming to identify its causative relation to the regional seismotectonic properties. In this respect, absolute and relative locations are paired and a catalog consisting of 2485 events was compiled. Relative locations are determined with high accuracy using the double-difference technique and differential times both from phase pick data and from cross-correlation measurements. The spatial distribution of the relocated events revealed a south-dipping causative fault along with secondary and smaller antithetic segments. Spatially, the seismicity started at the westernmost part and migrated with time to the easternmost part of the activated area. Temporally, two distinctive periods are observed, namely an early period lasting 1 month and a second period which includes the largest events in the sequence. The investigation of the interevent time distribution revealed a triggering mechanism, whereas the ETAS parameters show a strong external force (μ > 1), which might be attributed to the existence of the Tuzla geothermal field.

Loss of Mob1a/b in mice results in chondrodysplasia due to YAP1/TAZ-TEAD-dependent repression of SOX9.

Hippo signaling is modulated in response to cell density, external mechanical forces, and rigidity of the extracellular matrix (ECM). The Mps one binder kinase activator (MOB) adaptor proteins are core components of Hippo signaling and influence Yes-associated protein 1 (YAP1) and transcriptional co-activator with PDZ-binding motif (TAZ), which are potent transcriptional regulators. YAP1/TAZ are key contributors to cartilage and bone development but the molecular mechanisms by which the Hippo pathway controls chondrogenesis are largely unknown. Cartilage is rich in ECM and also subject to strong external forces - two upstream factors regulating Hippo signaling. Chondrogenesis and endochondral ossification are tightly controlled by growth factors, morphogens, hormones, and transcriptional factors that engage in crosstalk with Hippo-YAP1/TAZ signaling. Here, we generated tamoxifen-inducible, chondrocyte-specific Mob1a/b-deficient mice and show that hyperactivation of endogenous YAP1/TAZ impairs chondrocyte proliferation and differentiation/maturation, leading to chondrodysplasia. These defects were linked to suppression of SOX9, a master regulator of chondrogenesis, the expression of which is mediated by TEAD transcription factors. Our data indicate that a MOB1-dependent YAP1/TAZ-TEAD complex functions as a transcriptional repressor of SOX9 and thereby negatively regulates chondrogenesis.

Fluid structure interaction with curved space lattice Boltzmann

We present a novel method for fluid structure interaction (FSI) simulations where an original 2nd-order curved space lattice Boltzmann fluid solver (LBM) is coupled to a finite element method (FEM) for thin shells. The LBM can work independently on a standard lattice in curved coordinates without the need for interpolation, re-meshing or an immersed boundary. The LBM distribution functions are transformed dynamically under coordinate change. In addition, force and momentum can be calculated on the nodes exactly in any geometry. Furthermore, the FEM shell is a complete numerical tool with implementations such as growth, self-contact and strong external forces. We show resolution convergent error for standard tests under metric deformation. Mass and volume conservation, momentum transfer, boundary-slip and pressure maintenance are verified through specific examples. Additionally, a brief deformation stability analysis is carried out. Next, we study the interaction of a square fluid flow channel to a deformable shell. Finally, we simulate a flag at moderate Reynolds number, air flow channel. The scheme is limited to small deformations of O(10%) relative to domain size, by improving its stability the method can be naturally extended to multiple applications without further implementations.

On the adhesive JKR contact and rolling models for reduced particle stiffness discrete element simulations

Discrete Element Method (DEM) simulations are a promising approach to accurately predict agglomeration and deposition of micron-sized adhesive particles. However, the mechanistic models in DEM combined with high particle stiffness for most common materials require time step sizes in the order of nanoseconds, which makes DEM simulations impractical for more complex applications.In this study, analytically derived guidelines on how to reduce computational time by using a reduced particle stiffness are given. The guidelines are validated by comparing simulations of particles with and without reduced particle stiffness to experimental data. Then two well-defined test cases are investigated to show the applicability of the guidelines.When introducing a reduced particle stiffness in DEM simulations by reducing the effective Young's modulus from E to Emod, the surface energy density γ in the adhesive Johnson-Kendall-Roberts (JKR) model by Johnson et al. [1] should be modified as γmod=γ (Emod/E)2/5. Using this relation, the stick/rebound threshold remains the same but the collision process takes place over a longer time period, which allows for a higher time step size. When rolling motion is important, the commonly used adhesive rolling resistance torque model proposed by Dominik and Tielens [2,3], Krijt et al. [4] can be used by modifying the contact radius ratio (a/a0)3/2 to (amod/a0,mod)3/2, while keeping the other terms unaltered in the description of the rolling resistance torque Mr,mod=−4FC (a/a0)3/2ξ. Furthermore, as the particle stiffness is reduced from E to Emod, the time period for collisions (or oscillations when particles stick upon impact) Δtcol is found to vary as Δtcol,mod=Δtcol(E/Emod)2/5. As the collision duration and the collision time step size are directly related, this criterion can be used to estimate how much the time step size can be changed when a reduced particle stiffness is introduced.Introducing particles with a reduced particle stiffness has some limitations when strong external forces are acting to break-up formed agglomerates or re-entrain particles deposited on a surface out into the free stream. Therefore, care should be taken in flows with high local shear to make sure that an external force, such as a fluid drag force, acting to separate agglomerated particles, is several orders of magnitude lower than the critical force required to separate particles.

Наступательный и оборонительный религиозный конфликт: геополитическая перспектива

The discussion of the offensive religious conflict in this paper emphasizes on the fact that those regional groups are offensive only because of their dissatisfaction with the status quo and their ability of resorting to force. The purpose of provoking conflict is the pursuit of absolute security as well as maximized benefit in fighting for religious survival space. And the ultimate goal of defensive religious conflict is whether or not to maintain a relatively safe independent development of their own state. The concern about the intentions, abilities and consequences of religious confrontation is the attempt to transform the international relations theory from political realism to religious realism. In the geopolitical sense, if there is no strong enough external force to dominate or intervene, or effective balance of consensus mechanism, then the regional advantageous religious power that are not satisfied with the status quo and have a certain degree of violent may ensure their living space and maximize their religious power through active “self-help”. And the religious conflict of the purpose of obtaining a relatively safe living space is essentially a respect for the idea that the various religious forces can coexist in the same region.

Current driven transition from Abrikosov-Josephson to Josephson-like vortex in mesoscopic lateral S/S'/S superconducting weak links.

Vortices are topological defects accounting for many important effects in superconductivity, superfluidity, and magnetism. Here we address the stability of a small number of such excitations driven by strong external forces. We focus on Abrikosov-Josephson vortex that appears in lateral superconducting S/S’/S weak links with suppressed superconductivity in S’. In such a system the vortex is nucleated and confined in the narrow S’ region by means of a small magnetic field and moves under the effect of a force proportional to an applied electrical current with a velocity proportional to the measured voltage. Our numerical simulations show that when a slow moving Abrikosov-Josephson vortex is driven by a strong constant current it becomes unstable with respect to a faster moving excitation: the Josephon-like vortex. Such a current-driven transition explains the structured dissipative branches that we observe in the voltage-current curve of the weak link. When vortex matter is strongly confined phenomena as magnetoresistance oscillations and reentrance of superconductivity can possibly occur. We experimentally observe these phenomena in our weak links.

Origin of the effective mobility in non-linear active micro-rheology.

The distinction between the damping coefficient and the effective non-linear mobility of driven particles in active micro-rheology of supercooled liquids is explained in terms of individual and collective dynamics. The effective mobility arises as a collective effect which gives insight into the energy landscape of the system. On the other hand, the damping coefficient is a constant that modulates the effect of external forces over the thermal energy which particles have at their disposition to perform Brownian motion. For long times, these thermal fluctuations become characterized in terms of an effective temperature that is a consequence of the dynamic coupling between kinetic and configurational degrees of freedom induced by the presence of the strong external force. The interplay between collective mobility and effective temperature allows to formulate a generalized Stokes-Einstein relation that may be used to determine the collective diffusion coefficient. The explicit relations we deduce reproduce simulation data remarkably well.

Solitary waves propagation described by Korteweg-de Vries equation in the granular chain with initial prestress

The paper work relates to Nesterenko’s problem to further study the solitary wave when the strong external force acts on the granular chain. We also study the problem under the long-wavelength approximation and find that such kind of solitary wave in system with the initial prestress can be described by the Korteweg-de Vries (KdV) equation. It is found that the results of analytical and numerical are in an excellent agreement. Furthermore, we study the scattering of the KdV solitary wave in different granular materials both in theoretical and numerical methods. It is found that the numbers and the amplitudes of both the reflected and the transmitted waves depend not only on the amplitude of the incident solitary wave but also on the variations of both sides of the discontinuity such as the mass, Young’s modulus or radius of the grains.

Active microrheology of hydrodynamically interacting colloids: Normal stresses and entropic energy density

A single Brownian “probe” particle is driven by an external force through a colloidal suspension and its motion studied to elucidate the relative impacts of external, Brownian, and interparticle forces on the suspension stress. As the probe moves through the suspension, distortions to and relaxation of the particle arrangement give rise to nonequilibrium stress. The shape of the distorted microstructure is set by the strength of the external force, F0, relative to the entropic restoring force, kT/ath, of the suspension, and by the balance of microscopic forces between the constituent particles. The former is given by the Péclet number, Pe≡F0/(2kT/ath), where kT is the thermal energy and ath is the thermodynamic size of the particles. The latter comprise external, Brownian, and interparticle forces, and the sensitivity of each to flow strength Pe is set by the dimensionless repulsion range, κ≡(ath−a)/a, where a is the hydrodynamic size of the particles. The total stress comprises hydrodynamic and entropic contributions which manifest as Brownian, interparticle, and external force-induced stress. To analyze the influence of these forces on structure and suspension stress as they evolve with flow strength, we formulate and solve a Smoluchowski equation analytically in the dual limits of weak and strong external force and hydrodynamic interactions, and numerically for arbitrary values of Pe and κ. Nonequilibrium statistical mechanics are then utilized to compute elements of the stress tensor. Owing to the axisymmetric geometry of the microstructure about the line of the external force, only the diagonal elements are nonzero. When hydrodynamic interactions are negligibly weak, only the hard-sphere interparticle force matters regardless of the flow strength, and the results of Zia and Brady [J. Rheol. 56(5), 1175–1208 (2012)] are recovered whereby normal stresses scale as Pe2 and Pe in the limits of weak and strong forcing, respectively. That is, entropic forces dominate suspension stress regardless of the value of Pe when hydrodynamic interactions are weak. As the repulsion range κ shrinks, hydrodynamic interactions begin to play a role: When forcing is weak, Brownian disturbance flows provide the dominant contribution to suspension stress, but as Pe increases, the external force-induced stress takes over to dominate the total stress. Interestingly, the total suspension stress decreases as the strength of hydrodynamic interactions increases, regardless of the value of Pe. That is, hydrodynamic interactions suppress suspension stress. Owing to the dependence of hydrodynamic interactions on particle configuration, this stress suppression varies with flow strength: At low Pe, the stress scales as Pe2 and the suppression is quantitative, whereas at high Pe, the stress scales as Peδ, where 1 ≥ δ ≥ 0.799 for hydrodynamic interactions spanning from weak to strong. We identify the origin of such suppression via an analysis of pair trajectories: While entropic forces—interparticle repulsion and Brownian motion—destroy reversible trajectories, hydrodynamic interactions suppress structural asymmetry and this underlies the suppression of the nonequilibrium stress. We relate the stress to the energy density: Hydrodynamic interactions shield particles from direct collisions and promote fore-aft and structural symmetry, resulting in reduced entropic energy storage.

Fragmentation of Fast Josephson Vortices and Breakdown of Ordered States by Moving Topological Defects

Topological defects such as vortices, dislocations or domain walls define many important effects in superconductivity, superfluidity, magnetism, liquid crystals, and plasticity of solids. Here we address the breakdown of the topologically-protected stability of such defects driven by strong external forces. We focus on Josephson vortices that appear at planar weak links of suppressed superconductivity which have attracted much attention for electronic applications, new sources of THz radiation, and low-dissipative computing. Our numerical simulations show that a rapidly moving vortex driven by a constant current becomes unstable with respect to generation of vortex-antivortex pairs caused by Cherenkov radiation. As a result, vortices and antivortices become spatially separated and accumulate continuously on the opposite sides of an expanding dissipative domain. This effect is most pronounced in thin film edge Josephson junctions at low temperatures where a single vortex can switch the whole junction into a resistive state at currents well below the Josephson critical current. Our work gives a new insight into instability of a moving topological defect which destroys global long-range order in a way that is remarkably similar to the crack propagation in solids.

Is an Embassy Really Necessary? Israeli–Spanish Relations in the 1960s

Spanish–Israeli relations expanded across numerous fields throughout the 1960s despite the absence of formal diplomatic ties. For all practical purposes, Israel’s Ministry of Foreign Affairs had a legation in Madrid during the second half of the 1960s, including at least 3 semi-official representatives operating with the full knowledge of Madrid. Clandestinely, a Mossad station worked in liaison with the local intelligence services. Absence of a full-fledged Israeli embassy did not prevent advancing bilateral ties, normalising Jewish affairs in Spain, or preventing both Powers from engaging in official and public occasions or behind the scenes. Systemic pressure, most evident in Madrid’s ascension to GATT, and the need to abide with its rules by liberalising trade with Israel did much to advance Spanish–Israeli bilateral ties in the 1960s. A strong systemic external force also brought change in their relations in the 1980s. The diplomatic breakthrough of January 1986 and establishment of full formal diplomatic relations between the Powers was largely the inevitable result of Spain’s entry into the European Economic Community.