Journal articles: 'Coupling condition'

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Guo, Yibin, Wanyou Li, Xiqun Lu, Zhijun Shuai, Donghua Wang, Xiuzhen Ma, and Dequan Zou. "Online measurement of torsional stiffness and fault analysis for flexible coupling under working condition." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 230, no. 18 (August 9, 2016): 3175–82. http://dx.doi.org/10.1177/0954406215608408.

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In this paper, a method of measuring the relative torsional angles of the flexible coupling under working condition was developed. A double-encoder measurement system was proposed to get the torsional angles. The torsional angles were divided into “constant torsional angle” and “alternating torsional angle”. The measured results were analyzed further, which were applied to a series of flexible couplings. Firstly, the torsional stiffness of D-type flexible coupling was obtained according to the relationship between torques and torsional angles. The proposed method overcomes the difficulty that the angular displacements of flexible coupling cannot be measured online under operating condition. The feasibility and accuracy of the method developed in this study was verified by comparing stiffness curve with unloading curve obtained from static torsional experiment and values from factory inspection report. Furthermore, in view of the tear fault of A-type flexible coupling in a diesel generator set, the maximum alternating torsional angles of A-type, B-type, and C-type flexible couplings were measured under working condition, then safety margins were obtained for the diesel generator set. According to the safety margins of the three kinds of couplings, C-type flexible coupling is chosen to replace A-type, which provided the basis for type selection of flexible coupling. Finally, the method developed in this study would also be applied to the operation monitoring and fault diagnosis of flexible coupling online.

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Cranston, M., and Feng-Yu Wang. "A condition for the equivalence of coupling and shift coupling." Annals of Probability 28, no. 4 (October 2000): 1666–79. http://dx.doi.org/10.1214/aop/1019160502.

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Kobayashi, Tatsuo, and Noriyasu Ohtsubo. "Yukawa coupling condition of orbifold models." Physics Letters B 245, no. 3-4 (August 1990): 441–46. http://dx.doi.org/10.1016/0370-2693(90)90671-r.

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O’Reilly, Ossian, and Jan Nordström. "Provably non-stiff implementation of weak coupling conditions for hyperbolic problems." Numerische Mathematik 150, no. 2 (January 5, 2022): 551–89. http://dx.doi.org/10.1007/s00211-021-01263-y.

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AbstractIn the context of coupling hyperbolic problems, the maximum stable time step of an explicit numerical scheme may depend on the design of the coupling procedure. If this is the case, the coupling procedure is sensitive to changes in model parameters independent of the Courant–Friedrichs–Levy condition. This sensitivity can cause artificial stiffness that degrades the performance of a numerical scheme. To overcome this problem, we present a systematic and general procedure for weakly imposing coupling conditions via penalty terms in a provably non-stiff manner. The procedure can be used to construct both energy conservative and dissipative couplings, and the user is given control over the amount of dissipation desired. The resulting formulation is simple to implement and dual consistent. The penalty coefficients take the form of projection matrices based on the coupling conditions. Numerical experiments demonstrate that this procedure results in both optimal spectral radii and superconvergent linear functionals.

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Guo, Jianxia. "Calculation accuracy of mathematical homogenization method for thermo-mechanical coupling problems." Thermal Science 25, no. 4 Part B (2021): 2957–64. http://dx.doi.org/10.2298/tsci2104957g.

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The paper analyzes the thermo-mechanical couplinag phenomenon under the condition of sliding contact, establishes the finite element analysis continuous model of thermo-mechanical coupling, and proposes the system dynamic equilibrium equation and thermodynamic equilibrium equation. The article analyzes the contact conditions between the objects in the system and obtains the objects? contact conditions? mathematical expression. On this basis, the constraint function is used to express the mathematical homogenization. We apply the variation principle to the constraint function and form a non-linear equation group with the system balance equation solve the thermal-mechanical coupling problem. The example shows that we use the constraint function method to solve the thermo-mechanical coupling problem, which has good convergence, stable algorithm, and the calculation result can reflect the actual situation.

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Barzdaitis, Vytautas, Marijonas Bogdevicius, and Rimantas Didžiokas. "Dynamic Processes of Rotating System with Coupling." Solid State Phenomena 113 (June 2006): 213–18. http://dx.doi.org/10.4028/www.scientific.net/ssp.113.213.

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The article concerns dynamics and vibration of a high power rotating system with toothed wheel coupling that inserts elastic plate packets. Theoretical modeling and simulation of the rotating system with toothed wheel coupling have been provided by a finite element method. Complex model involved a rotating system, hydrodynamic bearings and coupling. The dynamics of semi-couplings and plates have been simulated. Experimental measurement of vibration has been measured with stationary machine condition monitoring and a diagnostic system.

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Yi, KangHyun. "Output Voltage Analysis of Inductive Wireless Power Ttransfer with Series LC and LLC Resonance Operations Depending on Coupling Condition." Electronics 9, no. 4 (March 31, 2020): 592. http://dx.doi.org/10.3390/electronics9040592.

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This paper analyzes the output voltage of an inductive wireless power transfer (WPT) depending on coupling conditions. When the optimum efficiency and maximum output power are obtained, it is called critical coupling, so the receiving coil and the transmitting coil should be separated by a certain distance. When the distance between the transmitting coil and receiving coil is very short, it is called over coupling, and output power decreases with the optimal operating state of the critical coupling condition. To design the entire circuit system for the inductive WPT depending on the coupling condition, it is beneficial to analyze the output voltage according to a load variation, an input voltage, and an operating frequency. Therefore, the output voltage depending on the coupling condition in the inductive WPT is analyzed in this paper. The output voltage gain in critical coupling condition is greater than one and is not affected by a load variation by a series LC resonant operation. The reduced output power in an over coupling condition can be recovered by a series LLC resonant operation. In addition, the output voltage gain is almost one and is affected by the load variation in the over coupling condition. A 5W prototype is implemented with the wireless power consortium standard coils and experimental results are shown to verify theoretical analysis and operation.

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IMADO, Keiji, and Kiyoshi TERADA. "Novel coupling applicable in off-centered condition." Mechanical Engineering Journal 3, no. 1 (2016): 15–00328. http://dx.doi.org/10.1299/mej.15-00328.

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Yang, Jun, and Tadanobu Sato. "Influence of viscous coupling on seismic reflection and transmission in saturated porous media." Bulletin of the Seismological Society of America 88, no. 5 (October 1, 1998): 1289–99. http://dx.doi.org/10.1785/bssa0880051289.

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Abstract Wave propagation in saturated porous media involves complicated couplings between the solid skeleton and pore fluid. In particular, viscous coupling plays a key role because in general it makes wave propagation dispersive and dissipative. Although the importance of the viscous coupling in wave propagation in an unbounded saturated medium was recognized, the knowledge of its effect on the reflection and transmission from a saturated porous boundary is limited. A detailed investigation is therefore carried out in this article on the influence of viscous coupling in the reflection and transmission at an interface between saturated porous media and ordinary elastic media. The interface is considered to be either permeable or impermeable to include the effect of hydraulic boundary condition. In particular, the dependence of viscous coupling effect on the hydraulic condition at the interface is studied in this article. The variations of the reflection and transmission coefficients with the angle of incidence as well as the frequency for different values of viscous coupling are computed and compared for permeable interface and impermeable interface. In addition, the seismic reflection in two extreme cases of viscous coupling, that is, null viscous coupling and infinite viscous coupling, is discussed. The results indicate that the effect of viscous coupling is complicated; it depends strongly on the hydraulic condition at the interface as well as the frequency of the incident wave. Additionally, it depends upon the angle of incidence.

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Feng, Wei, Yaming Tang, and Bo Hong. "Landslide Hazard Assessment Methods along Fault Zones Based on Multiple Working Conditions: A Case Study of the Lixian–Luojiabu Fault Zone in Gansu Province (China)." Sustainability 14, no. 13 (July 2, 2022): 8098. http://dx.doi.org/10.3390/su14138098.

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Traditional landslide hazard assessment methods generally use the same evaluation model to carry out assessments under different working conditions. Due to the differences in landslide influence factors and model calculation methods considered under different working conditions, the evaluation results obtained using traditional methods are different from those of real-world scenarios. Therefore, research on optimal landslide hazard assessment methods for different working conditions is important for disaster prevention and mitigation in areas along fault zones. Taking the section along the Lixian–Luojiabu fault zone in Gansu province in China as the research area, a landslide hazard assessment was carried out under rainfall and earthquake conditions. A method based on the fractal theory–information coupling model is proposed for the rainfall condition, and a method based on an improved Newmark model considering matric suction is proposed for the earthquake condition. Under the rainfall condition, a landslide hazard assessment was carried out using the information model, the logistic regression model, the fractal theory model, the logistic regression–information coupling model and the fractal theory–information coupling model. Meanwhile, under the earthquake condition, an assessment was carried out using the traditional Newmark model and the improved Newmark model considering matric suction. Finally, the ROC curve and Kappa coefficient were used to test the accuracy of these evaluation models and to determine the optimal model under different working conditions. The results showed that the fractal theory–information coupling model had the largest AUC value and Kappa coefficient value under the rainfall condition (0.856 and 0.807, respectively). The test value of the logistic regression–information coupling model was second, and the values of the other three models were all lower than 0.8. This shows that the evaluation of the fractal theory–information coupling model is better than those of the other models under the rainfall condition. The AUC value and Kappa coefficient of the improved Newmark model under the earthquake condition were 0.805 and 0.794, respectively, which were larger than the test values of the traditional Newmark model. This shows that the evaluation of the proposed model is better than that of the traditional Newmark model under the earthquake condition. These research results provide a reference for landslide hazard assessments in areas with similar characteristics.

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Glasserman, Paul, and David D. Yao. "Optimal couplings are totally positive and more." Journal of Applied Probability 41, A (2004): 321–32. http://dx.doi.org/10.1239/jap/1082552208.

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An optimal coupling is a bivariate distribution with specified marginals achieving maximal correlation. We show that optimal couplings are totally positive and, in fact, satisfy a strictly stronger condition we call the nonintersection property. For discrete distributions we illustrate the equivalence between optimal coupling and a certain transportation problem. Specifically, the optimal solutions of greedily-solvable transportation problems are totally positive, and even nonintersecting, through a rearrangement of matrix entries that results in a Monge sequence. In coupling continuous random variables or random vectors, we exploit a characterization of optimal couplings in terms of subgradients of a closed convex function to establish a generalization of the nonintersection property. We argue that nonintersection is not only stronger than total positivity, it is the more natural concept for the singular distributions that arise in coupling continuous random variables.

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Glasserman, Paul, and David D. Yao. "Optimal couplings are totally positive and more." Journal of Applied Probability 41, A (2004): 321–32. http://dx.doi.org/10.1017/s0021900200112380.

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An optimal coupling is a bivariate distribution with specified marginals achieving maximal correlation. We show that optimal couplings are totally positive and, in fact, satisfy a strictly stronger condition we call the nonintersection property. For discrete distributions we illustrate the equivalence between optimal coupling and a certain transportation problem. Specifically, the optimal solutions of greedily-solvable transportation problems are totally positive, and even nonintersecting, through a rearrangement of matrix entries that results in a Monge sequence. In coupling continuous random variables or random vectors, we exploit a characterization of optimal couplings in terms of subgradients of a closed convex function to establish a generalization of the nonintersection property. We argue that nonintersection is not only stronger than total positivity, it is the more natural concept for the singular distributions that arise in coupling continuous random variables.

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Zhang, Jie, Kiet Tieu, Guillaume Michal, Hongtao Zhu, Liang Zhang, Lihong Su, Guanyu Deng, and Hui Wang. "A damping boundary condition for atomistic-continuum coupling." Chinese Physics B 26, no. 6 (May 2017): 068702. http://dx.doi.org/10.1088/1674-1056/26/6/068702.

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Shirzaei, Manoochehr, Thomas R. Walter, and Roland Bürgmann. "Coupling of Hawaiian volcanoes only during overpressure condition." Geophysical Research Letters 40, no. 10 (May 28, 2013): 1994–99. http://dx.doi.org/10.1002/grl.50470.

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Giraldi, F., and F. Petruccione. "Anomalies in Strongly Coupled Harmonic Quantum Brownian Motion." Open Systems & Information Dynamics 20, no. 01 (March 2013): 1350002. http://dx.doi.org/10.1142/s1230161213500029.

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The exact dynamics of a quantum damped harmonic oscillator coupled to a reservoir of boson modes has been formally described in terms of the coupling function, both in weak and strong coupling regime. In this scenario, we provide a further description of the exact dynamics through integral transforms. We focus on a special class of spectral densities, sub-ohmic at low frequencies, and including integrable divergencies referred to as photonic band gaps. The Drude form of the spectral densities is recovered as upper limit. Starting from special distributions of coherent states as external reservoir, the exact time evolution, described through Fox H-functions, shows long time inverse power law decays, departing from the exponential-like relaxations obtained for the Drude model. Different from the weak coupling regime, in the sub-ohmic condition, undamped oscillations plus inverse power law relaxations appear in the long time evolution of the observables position and momentum. Under the same condition, the number of excitations shows trapping of the population of the excited levels and oscillations enveloped in inverse power law relaxations. Similarly to the weak coupling regime, critical configurations give arbitrarily slow relaxations useful for the control of the dynamics. If compared to the value obtained in weak coupling condition, for strong couplings the critical frequency is enhanced by a factor 4.

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CHIU, CHUANG-HSIUNG, WEN-WEI LIN, and CHEN-CHANG PENG. "ASYMPTOTIC SYNCHRONIZATION IN LATTICES OF COUPLED NONIDENTICAL LORENZ EQUATIONS." International Journal of Bifurcation and Chaos 10, no. 12 (December 2000): 2717–28. http://dx.doi.org/10.1142/s0218127400001778.

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In this paper we study coupled nonidentical Lorenz equations with three different boundary conditions. Coupling rules and boundary conditions play essential roles in the qualitative analysis of solutions of coupled systems. By using Lyapunov stability theory, a sufficient condition is obtained for the global stability of trivial equilibrium of coupled system with Dirichlet condition. Then we restrict our attention on the dynamics of coupled nonidentical Lorenz equations with Neumann/periodic boundary condition and prove that the asymptotic synchronization occurs provided the coupling strengths are sufficiently large. That is, the difference between any two components of solution is bounded by the quantity O(ε/ max {c1, c2, c3}) as t → ∞, where ε is the maximal deviation of parameters of nonidentical Lorenz equations, and c1, c2 and c3 are the specified coupling strengths.

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Fui, Choong Jian, Mohd Sani Sarjadi, Shaheen M. Sarkar, and Md Lutfor Rahman. "Recent Advancement of Ullmann Condensation Coupling Reaction in the Formation of Aryl-Oxygen (C-O) Bonding by Copper-Mediated Catalyst." Catalysts 10, no. 10 (September 24, 2020): 1103. http://dx.doi.org/10.3390/catal10101103.

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Transition metal-catalyzed chemical transformation of organic electrophiles and organometallic reagents belong to the most important cross coupling reaction in organic synthesis. The biaryl ether division is not only popular in natural products and synthetic pharmaceuticals but also widely found in many pesticides, polymers, and ligands. Copper catalyst has received great attention owing to the low toxicity and low cost. However, traditional Ullmann-type couplings suffer from limited substrate scopes and harsh reaction conditions. The introduction of homogeneous copper catalyst with presence of bidentate ligands over the past two decades has totally changed this situation as these ligands enable the reaction promoted in mild condition. The reaction scope has also been greatly expanded, rendering this copper-based cross-coupling attractive for both academia and industry. In this review, we will highlight the latest progress in the development of useful homogeneous copper catalyst with presence of ligand and heterogeneous copper catalyst in Ullmann type C-O cross-coupling reaction. Additionally, the application of Ullmann type C-O cross coupling reaction will be discussed.

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Mulyanto, Fiki T. Akbar, and Bobby E. Gunara. "General Couplings Conditions of Four-Dimensional Maxwell-Klein-Gordon System." Journal of Physics: Conference Series 2243, no. 1 (June 1, 2022): 012096. http://dx.doi.org/10.1088/1742-6596/2243/1/012096.

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Abstract In this paper, we investigate the conditions for the Maxwell Klein Gordon system’s general gauge couplings in (3 + 1)-dimensional Minkowski spacetime. For the multi-interaction of photons and charged spin-0 particle, we begin with the Lagrangian with the general coupling turned on. The equation of motion is then derived in the form of a nonlinear wave equation. We obtained the general solution for the vector potential using the spherical means method. By considering the Coulomb gauge condition, we get the constraint for the couplings, which are critical in proving the global well-posedness of the solution.

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Wang, Zhao, Zhi Jin Zhou, Hao Lu, Ze Jun Wen, and Yi Min Xia. "Coupling Model Analysis on Fluid Structure Interaction in Lifting Pipeling Based on ADINA." Advanced Materials Research 468-471 (February 2012): 238–44. http://dx.doi.org/10.4028/www.scientific.net/amr.468-471.238.

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Using finite element software ADINA, three coupling models on fluid-structure interaction among internal fluid—pipe—external fluid in the lifting pipeline were researched. Firstly, coupling finite element model on fluid structure interaction of lifting pipeline was established and the first sixth order natural frequencies and principal vibration modes were attained at different ore conveying volume concentration and cross-section size of pipeline;Then natural frequencies of three couplings were compared with two couplings and no coupling according to the above condition, and FSI effect on natural frequency of pipeline was discussed. The calculation results were shown that the natural frequency of the pipe and its relative error reduced with the volume concentration and the relative wall thickness increased, which explain the reason that has better accuracy considering three couplings than other .These results have certain directive significance on the dynamic response, structure design and study of reduction vibration of lifting pipeline.

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Uchino, Kenji. "Electrothermal Phenomena in Ferroelectrics." Actuators 9, no. 4 (September 23, 2020): 93. http://dx.doi.org/10.3390/act9040093.

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Physical properties of lead-zirconate-titanate (PZT) ceramics change according to the initial electric poling process and electrical boundary conditions. This paper reports the electrothermal, piezothermal, and piezoelectric coupling phenomena in ferroelectrics from thermodynamics viewpoints, in particular, thermal property differences between unpoled and poled PZT’s in the poling direction for open circuit and short circuit conditions. We propose a new terminology, “secondary electrothermal” coupling factor kλ, which is analogous to the electromechanical coupling factor k, relating the elastic compliances under short- and open-circuit conditions, in order to explain the fact that the short-circuit condition exhibited the larger thermal diffusivity than the open-circuit condition. On the other hand, the unpoled specimen exhibits the lowest thermal diffusivity. This tutorial paper was authored for providing comprehensive knowledge on equilibrium and time-dependent thermodynamics in ferroelectrics.

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Xue, Haojie, Di Tan, Shuaishuai Liu, Meng Yuan, and Chunming Zhao. "Research on the Electromagnetic-Heat-Flow Coupled Modeling and Analysis for In-Wheel Motor." World Electric Vehicle Journal 11, no. 2 (March 25, 2020): 29. http://dx.doi.org/10.3390/wevj11020029.

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In this paper, a 15 KW in-wheel motor (IWM) is taken as the research object, and the coupling factors among the electromagnetic field, temperature field and flow field are analyzed, and the strong and weak coupling factors between the three fields are clarified, and by identifying the strong and weak coupling factors between the three fields, a three-field coupling analysis model for IWM with appropriate complexity is established, and the validity of the model is verified. In a certain driving condition, the electromagnetic field, temperature field and flow field characteristics of IWM are analyzed with the multi-field coupling model. The result shows that, after the IWM runs 8440 s under driving conditions, in this paper, the IWM electromagnetic torque of the rated working condition is 134.2 Nm, and IWM the electromagnetic torque of the peak working condition is 451.36 Nm, and the power requirement of the motor can be guaranteed. The highest temperature of the IWM is 150 °C, which does not exceed the insulation grade requirements of the motor (155 °C), the highest temperature of the permanent magnet (PM) is 65.6 °C, and it does not exceed the highest operating temperature of the PM, and ensures the accurate calculation of components loss and the temperature of the motor. It can be found, through research, that the electromagnetic torque difference between unidirectional coupling and bidirectional coupling is 3.2%, the maximum temperature difference is 7.98% in the three-field coupling analysis of IWM under rated working conditions. Therefore, it is necessary to consider the influence of coupling factors on the properties of motor materials when analyzing the electromagnetic field, temperature field and flow field of IWM; it also provides some reference value for the simulation analysis of IWM in the future.

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FERNANDEZ, BASTIEN. "GLOBAL SYNCHRONIZATION IN TRANSLATION INVARIANT COUPLED MAP LATTICES." International Journal of Bifurcation and Chaos 18, no. 11 (November 2008): 3455–59. http://dx.doi.org/10.1142/s0218127408022494.

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A sufficient condition for global synchronization in coupled map lattices (CML) with translation invariant coupling and arbitrary individual map is proved. As in [Jost & Joy, 2001] where CML with reflection invariant couplings are considered, the condition only involves the linearized dynamics in the diagonal, namely for all points in the diagonal, the derivative must be contractive in all transverse directions. In addition to this result, a (weaker) condition that ensures the CML attractor to be composed of either 2-periodic or constant configurations, is also obtained.

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Yu, Jiangni, Lixiang Li, and Yixian Yang. "Topology Identification of Coupling Map Lattice under Sparsity Condition." Mathematical Problems in Engineering 2015 (2015): 1–6. http://dx.doi.org/10.1155/2015/303454.

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Coupling map lattice is an efficient mathematical model for studying complex systems. This paper studies the topology identification of coupled map lattice (CML) under the sparsity condition. We convert the identification problem into the problem of solving the underdetermined linear equations. Thel1norm method is used to solve the underdetermined equations. The requirement of data characters and sampling times are discussed in detail. We find that the high entropy and small coupling coefficient data are suitable for the identification. When the measurement time is more than 2.86 times sparsity, the accuracy of identification can reach an acceptable level. And when the measurement time reaches 4 times sparsity, we can receive a fairly good accuracy.

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Qi, Zheng, and Jian Jun Wang. "Excitation Order Research in Bladed-Disk Coupling Resonance Condition." Applied Mechanics and Materials 472 (January 2014): 31–35. http://dx.doi.org/10.4028/www.scientific.net/amm.472.31.

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In order to define the factors of excitation order in bladed-disk coupling resonance condition which affects the working life of the bladed-disk, a more accurate formula of excitation order is proposed. The graph of excitation order applied to a bladed-disk structure is given firstly considering rotor-stator interaction. Then the formula of excitation order is developed according to the similarity of graph between aliasing and excitation order. Finally the formula verification of excitation order is given both numerically and experimentally using a typical bladed-disk model. The study shows that the excitation order applied to bladed-disk structure only has to do with the number of rotor blade and stator vane ,which avoids the uncertainty of previous conclusion.

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Triantafyllou, George S. "Physical condition for absolute instability in inviscid hydroelastic coupling." Physics of Fluids A: Fluid Dynamics 4, no. 3 (March 1992): 544–52. http://dx.doi.org/10.1063/1.858326.

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Wright, Andrew N., and Alexander J B. Russell. "Alfvén wave boundary condition for responsive magnetosphere-ionosphere coupling." Journal of Geophysical Research: Space Physics 119, no. 5 (May 2014): 3996–4009. http://dx.doi.org/10.1002/2014ja019763.

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Werner, Adam F., Jamie C. Gorman, and Michael J. Crites. "Communication of Visual and Auditory Information and The Coordination of Team Task Performance." Proceedings of the Human Factors and Ergonomics Society Annual Meeting 63, no. 1 (November 2019): 1719–23. http://dx.doi.org/10.1177/1071181319631021.

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Due to lack of visual or auditory perceptual information, many tasks require interpersonal coordination and teaming. Dyadic verbal and/or auditory communication typically results in the two people becoming informationally coupled. This experiment examined coupling by using a two-person remote navigation task where one participant blindly drove a remote-controlled car while another participant provided auditory, visual, or a combination of both cues (bimodal). Under these conditions, we evaluated performance using easy, moderate, and hard task difficulties. We predicted that the visual condition would have higher performance measures overall, and the bimodal condition would have higher performance as difficulty increased. Results indicated that visual coupling performs better overall compared to auditory coupling and that bimodal coupling showed increased performance as task difficulty went from moderate to hard. When auditory coupling occurs, the frequency at which teams communicate affects performance— the faster teams spoke, the better they performed, even with visual communication available.

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Zhang, Nanyin, Zhongming Liu, Bin He, and Wei Chen. "Noninvasive Study of Neurovascular Coupling during Graded Neuronal Suppression." Journal of Cerebral Blood Flow & Metabolism 28, no. 2 (August 15, 2007): 280–90. http://dx.doi.org/10.1038/sj.jcbfm.9600531.

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In this study, the neurovascular coupling relationship was noninvasively studied in the human visual cortex. Graded neuronal/hemodynamic suppression conditions were generated using a paired-stimulus paradigm. Visual evoked potential was measured to quantify neuronal activity. Hemodynamic activities were measured and quantified by perfusion and blood oxygenation level-dependent changes. All quantification was normalized to the same activation condition induced by a single stimulus paradigm within each experimental session. This experiment design eliminated the confounding factors such as anesthesia and inconsistent neurovascular coupling patterns within and/or among tasks. The results reveal that (i) there is a tight neurovascular coupling at graded neuronal suppression conditions; (ii) the neurovascular coupling relationship contains a subtle, but significant, nonlinear component; and (iii) the linear model, nevertheless, is still a good approximation reflecting the neurovascular coupling relationship. This study extends the range of the neurovascular coupling relationship from graded neuronal excitation conditions to graded neuronal suppression conditions.

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Vignais, Nicolas, Benoit Bideau, Cathy Craig, Sébastien Brault, Franck Multon, and Richard Kulpa. "Virtual Environments for Sport Analysis: Perception-Action Coupling in Handball Goalkeeping." International Journal of Virtual Reality 8, no. 4 (January 1, 2009): 43–48. http://dx.doi.org/10.20870/ijvr.2009.8.4.2748.

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In sports science, the link between the experimental protocol and the subject's behaviour in real condition is a key issue. Virtual reality enables to examine this topic because of the reproducibility of situations and the total control of animated humanoids in situations similar to the real world. This study aimed to analyze the influence of the degree of perception-action coupling on the performance of handball goalkeepers in a virtual environment. 8 national handball goalkeepers were asked to react to the actions of a virtual handball thrower in two conditions: a perception-action uncoupled condition (defined as a judgment task) and a perception-action coupled condition (defined as a motor task). In the judgment condition, goalkeepers were asked to make a perceptual judgment with their hand in their own time after the virtual throw; in the motor task condition, goalkeepers had to react in real-time to the virtual throwing motion. Results showed that percentage of successful response was higher in the motor task condition and radial error (distance between the ball and the closest limb when trial was unsuccessful) was lower for the same condition. Implications of our findings are discussed, as well as suggestions for further research..

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Papaioannou, Orestis, Laura P. Crespo, Kailey Clark, Nicole N. Ogbuagu, Luz Maria Alliende, Steven M. Silverstein, and Molly A. Erickson. "Is Cortical Theta-Gamma Phase-Amplitude Coupling Memory-Specific?" Brain Sciences 12, no. 9 (August 25, 2022): 1131. http://dx.doi.org/10.3390/brainsci12091131.

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One of the proposed neural mechanisms involved in working memory is coupling between the theta phase and gamma amplitude. For example, evidence from intracranial recordings shows that coupling between hippocampal theta and cortical gamma oscillations increases selectively during working memory tasks. Theta-gamma phase-amplitude coupling can also be measured non-invasively through scalp EEG; however, EEG can only assess coupling within cortical areas, and it is not yet clear if this cortical-only coupling is truly memory-specific, or a more general phenomenon. We tested this directly by measuring cortical coupling during three different conditions: a working memory task, an attention task, and a passive perception condition. We find similar levels of theta-gamma coupling in all three conditions, suggesting that cortical theta-gamma phase-amplitude coupling is not a memory-specific signal, but instead reflects some other attentional or perceptual processes. Implications for understanding the brain dynamics of visual working memory are discussed.

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Deltour, Charles, Bart Dingenen, Filip Staes, Kevin Deschamps, and Giovanni A. Matricali. "Preliminary Evidence That Taping Does Not Optimize Joint Coupling of the Foot and Ankle Joints in Patients with Chronic Ankle Instability." International Journal of Environmental Research and Public Health 18, no. 4 (February 19, 2021): 2029. http://dx.doi.org/10.3390/ijerph18042029.

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Background: Foot–ankle motion is affected by chronic ankle instability (CAI) in terms of altered kinematics. This study focuses on multisegmental foot–ankle motion and joint coupling in barefoot and taped CAI patients during the three subphases of stance at running. Methods: Foot segmental motion data of 12 controls and 15 CAI participants during running with a heel strike pattern were collected through gait analysis. CAI participants performed running trials in three conditions: barefoot running, and running with high-dye and low-dye taping. Dependent variables were the range of motion (RoM) occurring at the different inter-segment angles as well as the cross-correlation coefficients between predetermined segments. Results: There were no significant RoM differences for barefoot running between CAI patients and controls. In taped conditions, the first two subphases only showed RoM changes at the midfoot without apparent RoM reduction compared to the barefoot CAI condition. In the last subphase there was limited RoM reduction at the mid- and rearfoot. Cross-correlation coefficients highlighted a tendency towards weaker joint coupling in the barefoot CAI condition compared to the controls. Joint coupling within the taped CAI conditions did not show optimization compared to the barefoot CAI condition. Conclusions: RoM was not significantly changed for barefoot running between CAI patients and controls. In taped conditions, there was no distinct tendency towards lower mean RoM values due to the mechanical restraints of taping. Joint coupling in CAI patients was not optimized by taping.

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Wu, Yen Chieh, Giovanni Cascante, and Mahesh D. Pandey. "Condition assessment of longitudinal pavement joints using ultrasonic surface waves." Canadian Journal of Civil Engineering 41, no. 12 (December 2014): 1019–28. http://dx.doi.org/10.1139/cjce-2013-0301.

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Poor-quality longitudinal joints can cause premature failure on asphalt pavements; they are characterized by exhibiting low density and high permeability. These conditions generate surface distresses such as longitudinal cracking. Previous ultrasonic methods for condition assessment, e.g., Fourier and wavelet transmission coefficient, require user input, making the automatic data processing difficult. Furthermore, the coupling between ultrasonic transducers and the asphalt surface is not practical for testing in-service roads. This paper presents a new data analysis technique and the results of an experimental program for the condition assessment of longitudinal asphalt joints using ultrasonic surface waves. A new coupling system between the ultrasonic transducers and the asphalt surface is presented. The new data processing technique reduces user input and increases testing reliability. The new coupling system uses polyurethane foam and calibrated weights to provide a spring action on the transducers. The proposed data analysis technique, called instantaneous transmission coefficient (ITC), is based on the evaluation of instantaneous frequencies and damping ratios. The main advantage of the new procedure is that it can be performed automatically, reducing user input and increasing test repeatability. A laboratory scale asphalt slab is used to show the potential of the new methodology and coupling system. Laboratory validation results show good agreement between the new ITC method and previous methods, and a significant reduction in testing time, while improving test reliability.

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LU, HONGTAO, and GUANRONG CHEN. "GLOBAL SYNCHRONIZATION IN AN ARRAY OF LINEARLY COUPLED DELAYED NEURAL NETWORKS WITH AN ARBITRARY COUPLING MATRIX." International Journal of Bifurcation and Chaos 16, no. 11 (November 2006): 3357–68. http://dx.doi.org/10.1142/s0218127406016847.

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In this paper, we investigate global synchronization in an array of linearly coupled identical delayed neural networks. We consider the array with an arbitrary coupling matrix without assuming it to be symmetric, irreducible and diffusive. Moreover, we consider the array being connected through two different coupling schemes, state-coupling and output-coupling, respectively. For state-coupling, we derive a more general sufficient condition ensuring global synchronization, which is an extension of some existing results in the literature. For output-coupling, we derive a new sufficient condition for global synchronization. Numerical simulations are given to illustrate the theoretical results.

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OGUCHI, TOSHIKI, and HENK NIJMEIJER. "A SYNCHRONIZATION CONDITION FOR COUPLED NONLINEAR SYSTEMS WITH TIME-DELAY: A FREQUENCY DOMAIN APPROACH." International Journal of Bifurcation and Chaos 21, no. 09 (September 2011): 2525–38. http://dx.doi.org/10.1142/s0218127411029902.

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This paper considers the synchronization problem for nonlinear systems with time-delay couplings. We assume that the error dynamics can be rewritten as a feedback connection of a linear delay system with multiple inputs and outputs and nonlinear elements which are decentralized and satisfy a sector condition. Then, we derive a synchronization condition for time-delay coupled systems by applying the multivariable circle criterion. Unlike the conventional synchronization criteria, the derived criterion is based on a frequency-domain stability condition and avoids the use of the Lyapunov–Krasovskii approach. As a result, the condition based on the circle criterion does not contain the conservativeness caused by the Lyapunov–Krasovskii approach. The effectiveness of the proposed criterion is shown by examples of coupled Chua systems with delay coupling.

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LIN, WEN-WEI, CHEN-CHANG PENG, and CHERN-SHUH WANG. "SYNCHRONIZATION IN COUPLED MAP LATTICES WITH PERIODIC BOUNDARY CONDITION." International Journal of Bifurcation and Chaos 09, no. 08 (August 1999): 1635–52. http://dx.doi.org/10.1142/s0218127499001139.

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We consider a lattice of coupled logistic maps with periodic boundary condition. We prove that synchronization and almost synchronization occur for the case of 1D lattice with lattice size n=2, 3, 4 provided the coupling strength c is chosen in a suitable open interval contained in [Formula: see text]. For the case of lattice size n≥4, we also show the numerical results of (almost) synchronized chaotic behavior of the coupled map lattice. For each fixed parameter γ∈ [3.57, 4] of the logistic maps, the lattice sizes and the ranges of the coupling strengths c so that the coupled map lattice is synchronized, are given.

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LUCHA, WOLFGANG, and MICHAEL MOSER. "CLIFFORD ALGEBRAS IN FINITE QUANTUM FIELD THEORIES I." International Journal of Modern Physics A 13, no. 13 (May 20, 1998): 2047–73. http://dx.doi.org/10.1142/s0217751x98000901.

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Finite quantum field theories may be constructed from the most general renormalizable quantum field theory by forbidding, order by order in the perturbative loop expansion, all ultraviolet-divergent renormalizations of the physical parameters of the theory. The relevant finiteness conditions resulting from this requirement relate all dimensionless couplings in the theory. At first sight, Yukawa couplings which are equivalent to the generators of some Clifford algebra with identity element represent a very promising type of solutions of the condition for one-loop finiteness of the Yukawa couplings. However, under a few reasonable and simplifying assumptions about their particular structure, these Clifford-like Yukawa couplings prove to be in conflict with the requirements of one- and two-loop finiteness of the gauge coupling and of the absence of gauge anomalies, at least for all simple gauge groups up to and including rank 8.

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Liu, Xianshan, and Ming Xu. "The Unsaturated Hydromechanical Coupling Model of Rock Slope Considering Rainfall Infiltration Using DDA." Geofluids 2017 (2017): 1–15. http://dx.doi.org/10.1155/2017/1513421.

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Water flow and hydromechanical coupling process in fractured rocks is more different from that in general porous media because of heterogeneous spatial fractures and possible fracture-dominated flow; a saturated-unsaturated hydromechanical coupling model using a discontinuous deformation analysis (DDA) similar to FEM and DEM was employed to analyze water movement in saturated-unsaturated deformed rocks, in which the Van-Genuchten model differently treated the rock and fractures permeable properties to describe the constitutive relationships. The calibrating results for the dam foundation indicated the validation and feasibility of the proposed model and are also in good agreement with the calculations based on DEM still demonstrating its superiority. And then, the rainfall infiltration in a reservoir rock slope was detailedly investigated to describe the water pressure on the fault surface and inside the rocks, displacement, and stress distribution under hydromechanical coupling conditions and uncoupling conditions. It was observed that greater rainfall intensity and longer rainfall time resulted in lower stability of the rock slope, and larger difference was very obvious between the hydromechanical coupling condition and uncoupling condition, demonstrating that rainfall intensity, rainfall time, and hydromechanical coupling effect had great influence on the saturated-unsaturated water flow behavior and mechanical response of the fractured rock slopes.

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Tobing, L. Y. M. A. L., S. Darmawan, D. R. Lim, Mee-Koy Chin, and Ting Mei. "Relaxation of Critical Coupling Condition and Characterization of Coupling-Induced Frequency Shift in Two-Ring Structures." IEEE Journal of Selected Topics in Quantum Electronics 16, no. 1 (2010): 77–84. http://dx.doi.org/10.1109/jstqe.2009.2027890.

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Cui, Chao, Ting Ting Han, Meng Qiu Gao, Wei Lu, Chao Zou, and De Bo Song. "SCCMI Algorithm for Coupling Analysis of Multi-Lead Epileptic EEG Signals." Applied Mechanics and Materials 373-375 (August 2013): 681–84. http://dx.doi.org/10.4028/www.scientific.net/amm.373-375.681.

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Symbolic-code condition mutual information (SCCMI) algorithm is proposed,which can detect coupling between several systems.SCCMI combines condition mutual information with symbolic-code algorithm. Condition mutual information entropy is used to finding coupling degree between time series .The meaning of symbolic-code algorithm is to retention large scale information of time sequence, whats more ,reduce noise effect. SCCMI algorithm is used to analyze difference of coupling between epileptic EEG signals and normal ones .Hypothesis testing was done by SPSS.It turns out that the difference between epileptic EEG signals and normal ones is significant.SCCMI algorithm is proved to be effective. And coupling degree can be used as a parameter to measure if brain is healthy.

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Mirka, Gary A., Ann Baker, Angela Harrison, and Dan Kelaher. "The interaction between load and coupling during dynamic manual materials handling tasks." Occupational Ergonomics 1, no. 1 (January 31, 1998): 3–11. http://dx.doi.org/10.3233/oer-1998-1102.

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The purpose of this research was to determine the impact of coupling and load magnitude on trunk dynamics during lifting activities. Subjects lifted a box that simulated three levels of coupling: good, fair and poor and seven levels of mass: ranging from 4.5-31.5 kg. The dependent variables were the peak dynamic moment generated about the lumbosacral joint and the peak vertical ground reaction forces produced during the lift. The results show that at low levels of box mass there are no significant differences in trunk dynamics and resulting peak dynamic moment across the different coupling conditions. However, when loads greater than 13.5 kg were lifted, a change in the normal dynamics of the lifting motion was noted, but only in the poor coupling condition, indicating an interaction between load and coupling. The results of this study indicate that the role of coupling under dynamic lifting conditions has both a perceptual and biomechanical basis that need to be considered when designing manual materials handling tasks.

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Xin, Zhe, Shun Xi Wang, Ke Peng Zhang, Zhao Jing Li, and Feng Yun. "Boundary Conditions for Numerical Simulation of Diesel Water Jacket." Advanced Materials Research 291-294 (July 2011): 2328–33. http://dx.doi.org/10.4028/www.scientific.net/amr.291-294.2328.

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In the research of flow and heat transfer of the diesel engine cooling system, the boundary condition determination was often a difficult problem. The paper calculated the flow velocity and convective heat transfer coefficient respectively for a six-cylinder diesel engine under different boundary conditions which including the water jacket wall as adiabatic condition, average temperature condition, and the boundary conditions from the solid-fluid coupling calculating. And the calculated values of the jacket wall temperatures were compared with that of test. The results showed that the simulation with solid-fluid coupling boundary conditions had better precision. Based on the research, an improved structure design was conducted for the six-cylinder diesel engine, the results of simulation showed that the average flow speed at the internal surface of water jacket could reach up to 0.5m/s, the flow symmetry in each jacket got improved, and the convective heat transfer coefficient could reach more than 2000 W/m2·K. The improved cooling system can meet the design requirements.

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Xiao, Neng Qi, Ri Ping Zhou, and Xi Chen Lin. "Research on Marine Electric Propulsion Shafting under Electromechanical Coupling Condition." Applied Mechanics and Materials 607 (July 2014): 477–82. http://dx.doi.org/10.4028/www.scientific.net/amm.607.477.

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Through the establishment of motor electromechanical coupling vibration model, torsional vibration characteristics of motor is analyzed in starting process. With 1000T lubricating oil ship electric propulsion shafting as the object of study, the free vibration and the forced vibration characteristics are analyzed. In two cases of considering the electromagnetic excitation torque and without considering the electromagnetic excitation torque, the responded vibration of electric propulsion shafting is calculated. The low noise design of the motor and propulsion shafting provides a theoretical basis.

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Kadyan, Akhila, Anil Shaji, and Jino George. "Boosting Self-interaction of Molecular Vibrations under Ultrastrong Coupling Condition." Journal of Physical Chemistry Letters 12, no. 17 (April 29, 2021): 4313–18. http://dx.doi.org/10.1021/acs.jpclett.1c00552.

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Voss, R., C. Clemmesen, H. Baumann, and HH Hinrichsen. "Baltic sprat larvae: coupling food availability, larval condition and survival." Marine Ecology Progress Series 308 (February 16, 2006): 243–54. http://dx.doi.org/10.3354/meps308243.

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Funayama, Masahiro, Katsuji Mukaihara, Hiroyuki Morita, Tatsuo Okada, Nariyuki Tomonaga, Jun Izumi, Yoshitoshi Noda, and Mitsuo Maeda. "Widely Tunable Operation of Ti:Sapphire Lasers under Optimum Coupling Condition." Japanese Journal of Applied Physics 32, Part 2, No. 9B (September 15, 1993): L1332—L1334. http://dx.doi.org/10.1143/jjap.32.l1332.

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Zhang, Xiaoqian, Zheng Yan, and Qi Guo. "Study on Microscopic Mechanism of Electrokinetic Coupling under Steady Condition." IOP Conference Series: Materials Science and Engineering 677 (December 10, 2019): 052046. http://dx.doi.org/10.1088/1757-899x/677/5/052046.

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Koskinen, Kaj U. "Project-based company's vital condition: structural coupling. An autopoietic view." Knowledge and Process Management 16, no. 1 (January 2009): 13–22. http://dx.doi.org/10.1002/kpm.321.

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Volke, H. J., P. Dettmar, P. Richter, M. Rudolf, and U. Buhss. "On-Coupling and Off-Coupling of Neocortical Areas in Chess Experts and Novices." Journal of Psychophysiology 16, no. 1 (January 2002): 23–36. http://dx.doi.org/10.1027//0269-8803.16.1.23.

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Abstract This paper presents a pilot study on the differences in evoked EEG coherence measures (computed as zero-lagged cross-correlation, “EC”) between chess experts and novices while solving chess problems. One of our earlier investigations ( Volke, 1999 ) had shown that both location and direction of EC changes in task processing (compared with a resting condition) depend on the degree of task performance. As a result we postulated that when solving the same tasks experts and novices would show different EC. The results of the recent study confirmed this supposition. Chess tasks of varying difficulty were presented to 25 chess players of different performance levels. The EEG was recorded from 29 positions (enhanced 10:20-system). EC were computed for post-stimulus intervals of 1.6s. A special averaging procedure (considering Fisher's Z transformation) was applied for summarizing the single EC of each type of task. These subject- and task-related EC-values (29 × 28/2 = 406 values per frequency band) were subjected to a MANOVA after a two-staged principal component analysis. Significant differences between experts and novices, compared with the resting condition, were found in the delta frequency range. The relevant cortical areas of experts, defined by a topological analysis of the differentiating principal components, were located rather posterior and more in the right hemisphere, compared with those of the novices. Furthermore, the essential EC of the experts showed higher values in the task situation (“on-coupling”), compared with the resting condition, whereas those of the novices were lower (“off-coupling”). The results are interpreted as a higher task-related functional integration of the cortical areas in experts.

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Ponmurugan, M. "Attainability of Maximum Work and the Reversible Efficiency of Minimally Nonlinear Irreversible Heat Engines." Journal of Non-Equilibrium Thermodynamics 44, no. 2 (April 26, 2019): 143–53. http://dx.doi.org/10.1515/jnet-2018-0009.

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Abstract We use the general formulation of irreversible thermodynamics and study the minimally nonlinear irreversible model of heat engines operating between a time-varying hot heat source of finite size and a cold heat reservoir of infinite size. We find the criterion under which the optimized efficiency obtained by this minimally nonlinear irreversible heat engine can reach the reversible efficiency under the tight coupling condition: a condition of no heat leakage between the system and the reservoirs. We assume the rate of heat transfer from the hot to the cold heat reservoir obeys Fourier’s law and discuss physical conditions under which one can obtain the reversible efficiency in a finite time with finite power. We also calculate the efficiency at maximum power for the minimally nonlinear irreversible heat engine under the nontight coupling condition.

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HAN Yishuai, 韩毅帅, 孙天玉 SUN Tianyu, 贾慧民 JIA Huimin, 唐吉龙 TANG Jilong, 房丹 FANG Dan, 王登魁 WANG Dengkui, 王晓华 WANG Xiaohua, 张宝顺 ZHANG Baoshun, and 魏志鹏 WEI Zhipeng. "氮化铝微环谐振腔临界耦合条件及制备工艺研究." ACTA PHOTONICA SINICA 50, no. 5 (2021): 86. http://dx.doi.org/10.3788/gzxb20215005.0514003.

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Journal articles on the topic 'Coupling condition'

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