Dynamic occluding contours: a new external-energy term for snakes

Author(s):  
M.M. Covell ◽  
T.J. Darrell
2020 ◽  
Vol 13 (3) ◽  
pp. 68-85
Author(s):  
D. V. Streltsov

The article analyzes long-term external and internal factors determining the course of development of Russian-Japanese relations in 2019-2020. On the one hand, the anti-Russian component in Tokyo's foreign policy is shaped by its membership in the Security Treaty with the United States and its solidarity with the sanctions policy of the Group of Seven towards Russia. On the other hand, Japan and Russia are both interested interest in political cooperation in creating multilateral dialog mechanisms of international security in East Asia, resolving the nuclear issue on the Korean Peninsula, and easing tensions around territorial disputes in the East China and South China seas. Among the economic factors, the author focuses on the significant place of Russia in the context of Japan's task of diversifying sources of external energy supplies, as well as on Russia's desire to avoid unilateral dependence on the Chinese market while reorienting the system of foreign economic relations from the West to the East. Personal diplomacy of political leaders plays a significant role in relations between Russia and Japan, and, above all, close personal relationships and frequent meetings between Prime Minister Abe and President Putin, which make it possible to partially compensate the unfavorable image of the partner country in the public opinion of both Russia and Japan. Against the background of a deadlock in the Peace Treaty talks which emerged in 2019, the search for a way out of the diplomatic impasse is on the agenda. In the author's opinion, it would be appropriate at the first stage to proceed to the conclusion of a basic agreement on the basis bilateral relations, which would be "untied" from the Peace Treaty. In addition, Russia could stop criticizing Japan for its security policy and show greater understanding of the Japanese initiative in the field of quality infrastructure. In turn, Japan could take a number of strategic decisions on cooperation with Russia and announce them in the Prime Minister's keynote speech. In addition, Tokyo could stop positioning the issue of the peace Treaty as the main issue in relations with Russia, which would allow our countries to "untie" bilateral relations from the problem of border demarcation and focus on their positive agenda.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Mayank Garg ◽  
Jia En Aw ◽  
Xiang Zhang ◽  
Polette J. Centellas ◽  
Leon M. Dean ◽  
...  

AbstractBioinspired vascular networks transport heat and mass in hydrogels, microfluidic devices, self-healing and self-cooling structures, filters, and flow batteries. Lengthy, multistep fabrication processes involving solvents, external heat, and vacuum hinder large-scale application of vascular networks in structural materials. Here, we report the rapid (seconds to minutes), scalable, and synchronized fabrication of vascular thermosets and fiber-reinforced composites under ambient conditions. The exothermic frontal polymerization (FP) of a liquid or gelled resin facilitates coordinated depolymerization of an embedded sacrificial template to create host structures with high-fidelity interconnected microchannels. The chemical energy released during matrix polymerization eliminates the need for a sustained external heat source and greatly reduces external energy consumption for processing. Programming the rate of depolymerization of the sacrificial thermoplastic to match the kinetics of FP has the potential to significantly expedite the fabrication of vascular structures with extended lifetimes, microreactors, and imaging phantoms for understanding capillary flow in biological systems.


Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4378
Author(s):  
Jorge A. Reyes-Avendaño ◽  
Ciro Moreno-Ramírez ◽  
Carlos Gijón-Rivera ◽  
Hugo G. Gonzalez-Hernandez ◽  
José Luis Olazagoitia

Energy harvesting shock absorbers (EHSA) have made great progress in recent years, although there are still no commercial solutions for this technology. This paper addresses the question of whether, and under what conditions, an EHSA can completely replace a conventional one. In this way, any conventional suspension could be replicated at will, while recovering part of the wasted energy. This paper focuses on mimicking the original passive damper behavior by continuously varying the electrical parameters of the regenerative damper. For this study, a typical ball-screw EHSA is chosen, and its equivalent suspension parameters are tried to be matched to the initial damper. The methodology proposes several electrical control circuits that optimize the dynamic behavior of the regenerative damper from the continuous variation of a load resistance. The results show that, given a target damper curve, the regenerative damper can adequately replicate it when there is a minimum velocity in the damper. However, when the damper velocity is close to zero, the only way to compensate for inertia is through the introduction of external energy to the system.


Biosensors ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 65
Author(s):  
Puneet Manocha ◽  
Gitanjali Chandwani

Molecular communication is a bioinspired communication that enables macro-scale, micro-scale and nano-scale devices to communicate with each other. The molecular communication system is prone to severe signal attenuation, dispersion and delay, which leads to performance degradation as the distance between two communicating devices increases. To mitigate these challenges, relays are used to establish reliable communication in microfluidic channels. Relay assisted molecular communication systems can also enable interconnection among various entities of the lab-on-chip for sharing information. Various relaying schemes have been proposed for reliable molecular communication systems, most of which lack practical feasibility. Thus, it is essential to design and develop relays that can be practically incorporated into the microfluidic channel. This paper presents a novel design of passive in-line relay for molecular communication system that can be easily embedded in the microfluidic channel and operate without external energy. Results show that geometric modification in the microfluidic channel can act as a relay and restore the degraded signal up-to 28%.


1979 ◽  
Vol 57 (1) ◽  
pp. 71-76 ◽  
Author(s):  
Michael H. Abraham ◽  
Asadollah Nasehzadeh

A novel method for the assessment of the Ph4As+/Ph4B− assumption for free energies of transfer of single ions has recently been suggested by Treiner, and used by him to deduce that the assumption is not valid for transfers between water, propylene carbonate, sulpholane, dimethylsulphoxide, N-methyl-2-pyrrolidone, and perhaps also dimethylformamide. The basis of the method is the estimation of the free energy of cavity formation by scaled-particle theory, together with the hypothesis that the free energy of interaction of Ph4As+ (or Ph4B−) with solvent molecules is the same in all solvents, ΔGt0(int) = 0. It is shown in the present paper that (a) whether or not the Ph4As+/Ph4B− assumption applies to transfer to a given solvent depends on which other solvent is taken as the reference solvent in Treiner's method, (b) the calculation of the cavity free energy term by scaled-particle theory and by the theory of Sinanoglu – Reisse – Moura Ramos (SRMR) yields values so different that the method cannot be considered reliable, (c) the calculation of cavity enthalpies and entropies for Ph4As+ or Ph4B− by scaled-particle theory yields results that are chemically not reasonable, (d) the hypothesis that ΔGt0(int) = 0 conflicts with SRMR theory, and (e) the conclusions reached by Treiner are not in accord with recent work that in general supports the Ph4As+/Ph4B− assumption for solvents that are rejected by Treiner.


1993 ◽  
Vol 50 (2) ◽  
pp. 282-289 ◽  
Author(s):  
Paul A. del Giorgio ◽  
Robert H. Peters

We analyzed published rates of algal photosynthesis and plankton community respiration to test the hypothesis that the ratio of planktonic primary production to community (P/R) varies systematically with lake trophy. Regression analyses show that algal production and plankton respiration are closely related to chlorophyll concentrations for lakes spanning a wide trophic range. More surprisingly, plankton respiration exceeds algal photosynthesis in oligotrophic lakes, and P/R rises above unity only when chlorophyll concentrations are above 17 mg∙m−3. A simple allometric model based on the predicted biomasses of the different planktonic component yield rates of community respiration that are in good agreement with measured values. Moreover, the model suggest that in oligotrophic lakes, microbial respiration may greatly exceed the current estimates based on bacterial production data and that heterotrophs contribute proportionately more to total plankton metabolism than they do in eutrophic lakes. Because such high respiration rates require external energy subsidies, these results; challenge the view that pelagial communities of most lakes are even approximately self-supporting.


2018 ◽  
Vol 41 (6) ◽  
pp. 603-610 ◽  
Author(s):  
Tim Boussy ◽  
Tim Vandecasteele ◽  
Lisse Vera ◽  
Stijn Schauvliege ◽  
Matthew Philpott ◽  
...  

2017 ◽  
Vol 114 (29) ◽  
pp. 7513-7518 ◽  
Author(s):  
Ming Han ◽  
Jing Yan ◽  
Steve Granick ◽  
Erik Luijten

Thermal energy agitates all matter, and its competition with ordering tendencies is a fundamental organizing principle in the physical world; this observation suggests that an effective temperature might emerge when external energy input enhances agitation. However, despite the repeated proposal of this concept based on kinetics for various nonequilibrium systems, the value of an effective temperature as a thermodynamic control parameter has been unclear. Here, we introduce a two-component system of driven Janus colloids, such that collisions induced by external energy sources agitate the system, and we demonstrate quantitative agreement with hallmarks of statistical thermodynamics for binary phase behavior: the archetypal phase diagram with equilibrium critical exponents, Gaussian displacement distributions, and even capillarity. The significance is to demonstrate a class of dynamical conditions under which thermodynamic analysis extends quantitatively to systems that are decidedly nonequilibrium except that the effective temperature differs from the physical temperature.


2003 ◽  
Vol 13 (08) ◽  
pp. 1185-1217 ◽  
Author(s):  
Olivier Bokanowski ◽  
Benoît Grebert ◽  
Norbert J. Mauser

We deal with local density approximations for the kinetic and exchange energy term, ℰ kin (ρ) and ℰ ex (ρ), of a periodic Coulomb model. We study asymptotic approximations of the energy when the number of particles goes to infinity and for densities close to the constant averaged density. For the kinetic energy, we recover the usual combination of the von-Weizsäcker term and the Thomas–Fermi term. Furthermore, we justify the inclusion of the Dirac term for the exchange energy and the Slater term for the local exchange potential.


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