Articoli di riviste: "Couple dynamic"

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Pitti, Mary, e Michael Matheny. "Odd Couple? Or Dynamic Duo?" ASHA Leader 21, n. 6 (giugno 2016): 38–39. http://dx.doi.org/10.1044/leader.ae.21062016.38.

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L’Abate, Luciano. "Dynamic Assessment in Couple Therapy". American Journal of Psychotherapy 48, n. 2 (aprile 1994): 312–13. http://dx.doi.org/10.1176/appi.psychotherapy.1994.48.2.312.

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Lin, Jaw-Ren, Yeon-Pun, Yuan Kang e Kuo-Chiang Cha. "PURE SQUEEZE FILM BEHAVIOR OF LONG JOURNAL BEARINGS WITH COUPLE STRESS FLUIDS UNDER DYNAMIC LOADING". Transactions of the Canadian Society for Mechanical Engineering 24, n. 3-4 (settembre 2000): 477–92. http://dx.doi.org/10.1139/tcsme-2000-0036.

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On the basis of microcontinuum theory, a theoretical analysis of pure squeeze film behavior of journal bearings with couple stress lubricants operating under a dynamic load is presented. To account for the effects of couple stresses arising from the lubricant blended with various additives, the modified Reynolds equation governing the film pressure is obtained from Stokes equations of motion. Various bearing characteristics for long bearings are then calculated. According to the results obtained, the influence of couple stresses on the dynamic squeeze film motion is apparent and not negligible. Comparing with the Newtonian-lubricant case, the effects of coupe stresses provide and enhancement in the film pressure as well as a reduction in the velocity of the journal center; consequently, the maximum eccentricity ratio of the journal center is decreased. On the whole, the bearing lubricated with couple stress fluid signifies and improvement in the dynamic squeeze film performance and results in longer bearing life.

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Talabi, Adetoro Temitope, Victor Uzodinma Chukwuma e Rasaki Kolawole Odunaike. "MODIFIED NONLINEAR DYNAMICAL EQUATIONS FOR RELATIONSHIP IN MARRIAGES". African Journal of Science and Nature 7 (6 novembre 2020): 50. http://dx.doi.org/10.46881/ajsn.v7i0.156.

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Love-stories are characterized by temporal fluctuations, experiment in the area of relationship are difficult to design but mathematical models play vital role in studying the dynamics of relationships and their behavioural features. The paper examines relationship between different couples who are living together as ideal couple or fragile couple and the divorcee. A modified nonlinear coupled dynamic model was used to predict and interpret the feature of the union of different individuals and it is adapted to local environment where the data collection is carried out. We also investigated several measures affecting marriages, different challenges in marriage were considered by the use of questionnaires, analyzed and the results were applied as parameters in the model. In other words, only few of the behaviour of the couples to each other are taken into account while the rest of the answers were kept frozen, results were used to confirm if the behaviour of certain number of individuals observed in real life can be explained through the answers provided by individuals in the survey which was included in the theory. Numerical simulations are also presented to show the effectiveness of the survey results.

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Zeng, S., BL Wang e KF Wang. "Analyses of natural frequency and electromechanical behavior of flexoelectric cylindrical nanoshells under modified couple stress theory". Journal of Vibration and Control 25, n. 3 (26 luglio 2018): 559–70. http://dx.doi.org/10.1177/1077546318788925.

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Different from piezoelectric effect, the flexoelectric effect is size dependent and becomes more significant at nanoscale. A nonlinear dynamic model of nanoscale flexoelectric shells is developed based on modified couples stress theory. The governing equations for nonlinear vibration of a flexoelectric cylindrical nanoshell are obtained. The natural frequency and generated voltage of the flexoelectric cylindrical nanoshell is achieved. Effects of geometric dimension, character material length, and vibration amplitude on the natural frequency and the generated voltage are discussed in detail. Results demonstrate that modified couple stress theory and large deformation theory are coupled together and interact with each other in the analyses of natural frequency and electromechanical behavior. Simultaneously taking nonlinearity and couple stress theory into account is necessary.

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Talbot, Wendy. "Humor in Couple Relationships: An Opportunity for Therapeutic Inquiry". Journal of Systemic Therapies 40, n. 1 (maggio 2021): 1–16. http://dx.doi.org/10.1521/jsyt.2021.40.1.1.

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Humor has been a focus of therapy literature for over a century and is considered an essential communication tool and important component of therapeutic relationships. Yet couple therapy literature does not feature humor as a relational practice or strategy for couples’ relationship development. When humor presents in a therapy conversation it offers opportunities for therapists to explore the implications and meanings for the couple relationship, potentially contributing to new and enhanced relationship experience. This article provides vignettes from one couple therapy conversation to illustrate therapeutic possibilities for exploration of couples’ humor. Therapists are encouraged to pay attention to humor as a complex, dynamic, discursive practice with therapeutic benefits for couples’ therapy.

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Jacques, Glenys. "The Dynamic Flow of the Couple". Self & Society 33, n. 5 (marzo 2006): 41–43. http://dx.doi.org/10.1080/03060497.2006.11086270.

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V, Giridharan, e Sivakumar S. "Effect of Gyroscopic Couple on Aircraft Landing Gear Shimmy". Defence Science Journal 73, n. 06 (1 novembre 2023): 627–32. http://dx.doi.org/10.14429/dsj.73.18932.

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This article presents the effect of gyroscopic couples on the shimmy response of landing gear. The gyroscopic effect between the rotational motions of the aircraft’s longitudinal and vertical axes may be one of the causes of shimmy. The vertical load acting on the wheel axle plays a significant role in a tire’s dynamic characteristics, which may influence shimmy oscillation. So, vertical dynamics also need to be considered for shimmy analysis along with lateral and torsional modes. Suitable mathematical models are required to study the system’s shimmy oscillation and stability nature. The mathematical model was developed by introducing a gyroscopic couple with 5 degrees of freedom (DOF). A numeric analysis was made to investigate the influence of gyroscopic couples on the landing gear model. The simulation results of the model with and without gyroscopic couple are compared and the effect of each parameter on shimmy is studied.

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Pineda, J. R. E. T., e S. D. Schwartz. "Protein dynamics and catalysis: the problems of transition state theory and the subtlety of dynamic control". Philosophical Transactions of the Royal Society B: Biological Sciences 361, n. 1472 (12 luglio 2006): 1433–38. http://dx.doi.org/10.1098/rstb.2006.1877.

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This manuscript describes ongoing research on the nature of chemical reactions in enzymes. We will investigate how protein dynamics can couple to chemical reaction in an enzyme. We first investigate in some detail why transition state theory cannot fully describe the dynamics of chemical reactions catalysed by enzymes. We describe quantum theories of chemical reaction in condensed phase including studies of how the symmetry of coupled vibrational modes differentially affects reaction dynamics. We make reference to previous work in our group on a variety of condensed phase chemical reactions (liquid and crystalline) and a variety of enzymatically catalysed reactions including the reactions of lactate dehydrogenase and purine nucleoside phosphorylase. All the protein motions we have studied have been quite rapid. We will propose methods to find motions over a broad range of time-scales in enzymes that couple to chemical catalysis. We report recent findings which show that conformational fluctuations in lactate dehydrogenase can strongly affect its ability to catalyse reactions through protein motion, and that only a tiny minority of conformations appear to be catalytically competent.

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Li, Din Geng, Ji Guang Cao, Jun Wen Wang e Chuan Yao Chen. "The Design and Analysis of a New Type of Vibration Structure". Applied Mechanics and Materials 1-2 (settembre 2004): 71–80. http://dx.doi.org/10.4028/www.scientific.net/amm.1-2.71.

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In this paper, a new type of vibration structure (i.e. swing frame) of vertical dynamic balancing machine is designed, which is based on the analysis of traditional double-plane vertical dynamic balancing machine’s swing frame. The static unbalance and couple unbalance can be separated effectively by using the new dynamic balancing machine with the new swing frame. The modal and harmonic responses are analyzed by using the ANSYS7.0. By comparing the finite element modal analysis with the experimental modal analysis, the natural frequencies and vibration modes are found out, which can provide the dynamics direction for designing vertical dynamic balancing machine. The new dynamic balancing machine can measure static unbalance and couple unbalance directly, and the influence between them is faint. The practical result indicates that the new vertical dynamic balancing machine is suitable for inertial measurement of flying objects, and can overcome the shortcomings of traditional double-plane vertical dynamic balancing machines, in which the effect of plane-separation is inferior. The vertical dynamic balancing machine with the new vibration structure can be widely used in the future application.

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Drüke, Markus, Werner von Bloh, Stefan Petri, Boris Sakschewski, Sibyll Schaphoff, Matthias Forkel, Willem Huiskamp, Georg Feulner e Kirsten Thonicke. "CM2Mc-LPJmL v1.0: biophysical coupling of a process-based dynamic vegetation model with managed land to a general circulation model". Geoscientific Model Development 14, n. 6 (1 luglio 2021): 4117–41. http://dx.doi.org/10.5194/gmd-14-4117-2021.

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Abstract. The terrestrial biosphere is exposed to land-use and climate change, which not only affects vegetation dynamics but also changes land–atmosphere feedbacks. Specifically, changes in land cover affect biophysical feedbacks of water and energy, thereby contributing to climate change. In this study, we couple the well-established and comprehensively validated dynamic global vegetation model LPJmL5 (Lund–Potsdam–Jena managed Land) to the coupled climate model CM2Mc, the latter of which is based on the atmosphere model AM2 and the ocean model MOM5 (Modular Ocean Model 5), and name it CM2Mc-LPJmL. In CM2Mc, we replace the simple land-surface model LaD (Land Dynamics; where vegetation is static and prescribed) with LPJmL5, and we fully couple the water and energy cycles using the Geophysical Fluid Dynamics Laboratory (GFDL) Flexible Modeling System (FMS). Several improvements to LPJmL5 were implemented to allow a fully functional biophysical coupling. These include a sub-daily cycle for calculating energy and water fluxes, conductance of the soil evaporation and plant interception, canopy-layer humidity, and the surface energy balance in order to calculate the surface and canopy-layer temperature within LPJmL5. Exchanging LaD with LPJmL5 and, therefore, switching from a static and prescribed vegetation to a dynamic vegetation allows us to model important biospheric processes, including fire, mortality, permafrost, hydrological cycling and the impacts of managed land (crop growth and irrigation). Our results show that CM2Mc-LPJmL has similar temperature and precipitation biases to the original CM2Mc model with LaD. The performance of LPJmL5 in the coupled system compared to Earth observation data and to LPJmL offline simulation results is within acceptable error margins. The historical global mean temperature evolution of our model setup is within the range of CMIP5 (Coupled Model Intercomparison Project Phase 5) models. The comparison of model runs with and without land-use change shows a partially warmer and drier climate state across the global land surface. CM2Mc-LPJmL opens new opportunities to investigate important biophysical vegetation–climate feedbacks with a state-of-the-art and process-based dynamic vegetation model.

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Liu, Zhan Fang, e Shi Jun Yan. "Dynamics of A Single Elastic Bodies under Large Rigid Rotation". Applied Mechanics and Materials 226-228 (novembre 2012): 451–58. http://dx.doi.org/10.4028/www.scientific.net/amm.226-228.451.

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The generalized elasticity is presented where a modified constitutive relation for the couple stress is proposed. A rigid-flexible coupled model is set up where three types of additional inertia forces along with their increments are elucidated in the model. The finite element formulation is developed with the use of the constrained variational principle. As an example, a dynamic analysis on a rotating cantilever is numerically carried out. The dynamical responses of the displacement and rotational angle at the free end, the stress and couple stress at the fixed end of cantilever are presented. An idea of critical angular velocities is proposed to insure system stability. The displacement trajectory of the free end of cantilever is approached and the dynamic stiffening problem is discussed.

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Chen, Pengfan, Ying Wang, Wenhao Ding, Yafeng Niu, Zibo Lin e Yingwen Liu. "Performance analysis of free piston Stirling engine based on the phasor notation method". E3S Web of Conferences 313 (2021): 02004. http://dx.doi.org/10.1051/e3sconf/202131302004.

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The free piston Stirling engine (FPSE) is a couple system of dynamics and thermodynamics. Due to the complicated and interactive relationships between the dynamic parameters and thermodynamic parameters, the performance of the FPSE is always difficult to predict and evaluate. The phasor notation method is proposed based on a thermodynamic-dynamic coupled model of a beta-type FPSE in this paper. The output power and efficiency under the different heating temperature and charging pressure are analysed and compared. In addition, based on the Sage numerical model, the influences of heating temperature and charging pressure on the pistons’ displacement amplitudes, power work and efficiency are revealed. This study can provide the assistance for the performance analysis, prediction and optimization of the FPSE.

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Su, Y. A., e I. G. Tadjbakhsh. "Optimal Control of Beams With Dynamic Loading and Buckling". Journal of Applied Mechanics 58, n. 1 (1 marzo 1991): 197–202. http://dx.doi.org/10.1115/1.2897149.

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The vibration of beams can be suppressed by a set of discrete actuators associated with a causal optimal, coupled-modal control algorithm which is derived from minimizing a time-dependent weighted sum of the kinetic energy, potential energy, and the control effort. The control gains are functions of the control interval and couple the modes that participate in the control. The controller can be applied to control a beam subjected to a resonant cyclic load, a moving load, and a beam column subjected to a unit impuse at midspan before buckling.

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Morini, L., A. Piccolroaz e G. Mishuris. "Dynamic energy release rate in couple-stress elasticity". Journal of Physics: Conference Series 451 (17 luglio 2013): 012014. http://dx.doi.org/10.1088/1742-6596/451/1/012014.

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Rahaeifard, Masoud, Mohammad Taghi Ahmadian e Keikhosrow Firoozbakhsh. "Size-dependent dynamic behavior of microcantilevers under suddenly applied DC voltage". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 228, n. 5 (21 maggio 2013): 896–906. http://dx.doi.org/10.1177/0954406213490376.

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This paper investigates the dynamic behavior of microcantilevers under suddenly applied DC voltage based on the modified couple stress theory. The cantilever is modeled based on the Euler–Bernoulli beam theory and equation of motion is derived using Hamilton’s principle. Both analytical and numerical methods are utilized to predict the dynamic behavior of the microbeam. Multiple scales method is used for analytical analysis and the numerical approach is based on a hybrid finite element/finite difference method. The results of the modified couple stress theory are compared with those from the literature as well as the results predicted by the classical theory. It is shown that the modified couple stress theory predicts size-dependent normalized dynamic behavior for the microbeam while according to the classical theory the normalized behavior of the microbeam is independent of its size. When the thickness of the beam is in order of its material length scale, the difference between the results given by the modified couple stress theory and those predicted by the classical theory is considerable. As the beam thickness increases, the results of the modified couple stress theory converge to those of the classical theory.

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MUKHERJEE, SWARNAVA, SHANMUKH SARODE, CHINMAYEE MUJUMDAR, LIZHI SHANG e ANDREA VACCA. "EFFECT OF DYNAMIC COUPLING ON THE PERFORMANCE OF PISTON PUMP LUBRICATING INTERFACES". MM Science Journal 2022, n. 3 (27 settembre 2022): 5783–90. http://dx.doi.org/10.17973/mmsj.2022_10_2022075.

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The energy efficiency and durability performance of axial piston machines are strongly affected by the tribological behavior of their lubricating interfaces. State-of-the-art approaches typically study these interface in isolation, neglecting possible reciprocal interactions between such interfaces. This paper presents an investigation of the mutual interaction between the piston/cylinder interface and the slipper/swashplate interface of a commercial axial piston pump. The proposed model can predict distributive fluid behavior in the lubricating gaps considering the effects of dynamics of the solid bodies, compressibility, mixed lubrication, elastic deformation, and cavitation. The dynamic coupling between the piston and the slipper is achieved by modeling the friction between the piston ball and slipper socket based on the force balance and the relative motion between the two bodies. The efficiencies predicted by this coupled model are compared to the ones obtained through the more established approach of solving the lubricating interfaces independently. The simulation results demonstrate the influence of the coupled physics on the lubricating interface performance, confirming the necessity of considering couple dynamics in lubricating interface numerical modeling.

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Yang, Liang, Ming Qiu, Zhenqiang Liao, Jie Song, Zijian Li e Wenjun Huang. "Research on Vibration Control of Paired Inclined Nozzles Dynamic Coupled Tubes". Journal of Physics: Conference Series 2528, n. 1 (1 luglio 2023): 012040. http://dx.doi.org/10.1088/1742-6596/2528/1/012040.

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Abstract The barrel vibrates violently, which will lead to a serious drop in shooting accuracy. To solve this issue, a barrel vibration control method of the paired oblique nozzle dynamic couple is proposed. A pair of inclined nozzle devices are designed on the barrel to fully use the gunpowder gas energy in the chamber during the shooting process. A dynamic couple is generated to balance the turning moment of the barrel weapon. Simultaneously, the recoil force is reduced by exporting the gunpowder gas in the chamber. Therefore, the vibration of the barrel is reduced. Firstly, the internal ballistic two-phase flow model including the gas transient flow model in the vibration control device is modelled based on the internal ballistic theory of two-phase flow. Secondly, the numerical simulation of the weapon launching process is carried out. Thirdly, the rigid-flexible coupling firing dynamics modelling and simulation research is conducted on a 30mm chain gun equipped with a paired oblique nozzle dynamic couple vibration control device. At last, the effects of the device on the continuous firing vibration control of barrel weapons are analyzed. The results show that the vibration reduction efficiency of the inclined nozzle is better than that of the vertical nozzle and the horizontal nozzle. When the angle of the inclined nozzle is 30°, the barrel shows the highest vibration reduction efficiency. The vibration reduction efficiency of each vibration characteristic is 39.2%, 17.1%, 44.8%, and 48.9%, respectively.

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Soroush, Rahman, Ali Koochi, Maryam Keivani e Mohamadreza Abadyan. "A Bilayer Model for Incorporating the Coupled Effects of Surface Energy and Microstructure on the Electromechanical Stability of NEMS". International Journal of Structural Stability and Dynamics 17, n. 04 (6 aprile 2017): 1771005. http://dx.doi.org/10.1142/s0219455417710055.

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Herein, the static and dynamic pull-in instabilities of nanotweezers and nanoswitches fabricated from conductive cylindrical nanowires are studied. A bilayer model based on the Gurtin–Murdoch surface elasticity and the consistent couple stress theory is developed to incorporate the coupled effects of surface energy and microstructure phenomenon. The differential quadrature method is employed to solve the nonlinear governing equation of the system. The effects of various parameters on the static and dynamic pull-in parameters and stability threshold of the nanostructures are demonstrated.

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Yu, S. L., e C. Yap. "Investigating the Infertile Couple". Annals of the Academy of Medicine, Singapore 32, n. 5 (15 settembre 2003): 611–14. http://dx.doi.org/10.47102/annals-acadmedsg.v32n5p611.

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Introduction: Investigations play a pivotal role in the workup for infertility. The results must be interpreted carefully as these assess dynamic function. Evidence-based guidelines are useful in the selection of appropriate tests. Materials and Methods: A review of current evidence-based guidelines for the investigation and management of the infertile couple is undertaken. Results: The main areas that correlate with fecundability are ovulatory function, tubal patency and semen analysis. Conclusion: The appropriate selection of investigations based on problem areas identified by history and physical examination would guide the physician in the management of the infertile couple.

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Harries, Kent A., Denis Mitchell, Richard G. Redwood e William D. Cook. "Nonlinear seismic response predictions of walls coupled with steel and concrete beams". Canadian Journal of Civil Engineering 25, n. 5 (1 ottobre 1998): 803–18. http://dx.doi.org/10.1139/l98-015.

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The design and nonlinear dynamic analyses of four coupled wall prototype structures are presented. Two ductile partially coupled and two ductile coupled wall structures are considered, each having reinforced concrete and steel coupling beams. The design of each of the prototype structures was based on the provisions of the 1995 National Building Code of Canada. Nonlinear dynamic analyses of each structure, using four different scaled earthquake ground motions are presented and the results discussed. Comparisons of the responses of the structures with concrete and steel coupling beams are made, demonstrating the advantages of using steel beams to couple reinforced concrete walls.Key words: composite construction, coupled wall, diagonally reinforced concrete coupling beam, "flexure critical" steel coupling beam, seismic design, "shear critical" steel coupling beam.

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Wiedermann, Klaus. "Fear of Break-up, Fear of Breakdown: Why Some Can Come to Psychoanalysis Only as a Partner in a Couple". Couple and Family Psychoanalysis 7, n. 2 (30 settembre 2017): 208–24. http://dx.doi.org/10.33212/cfp.v7n2.2017.208.

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This paper summarises the theory of psychoanalytic couple therapy from the point of view of contemporary object relations theory(s) and then locates psychoanalytic couple therapy in the larger context of psychoanalysis. The author asks why some individuals get the therapy they need by being brought in by their partners, seeming to enter treatment because of a threatened break-up of the couple relationship or a breakdown in one of the partners. The author observes that in these cases unresolved aspects of the self have been located in the partner to such an extent, that at least one partner will initially be very resistant to any form of dynamic therapy, including couple therapy. Winnicott's concepts of "undifferentiation" between self and other and "fear of breakdown", and Colman's concept of "marriage as a psychological container" are used to investigate the couple dynamics in those circumstances. Clinical examples show the slow process of disentangling and reclaiming projected aspects of the self from the shared unconscious phantasy created by the two partners.

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Yan, Fa Suo, Peng Fei Shen, Hong Wei Wang e Jun Zhang. "A Coupled Method for Dynamic Analysis of Offshore Floating Wind Turbine System". Applied Mechanics and Materials 220-223 (novembre 2012): 841–44. http://dx.doi.org/10.4028/www.scientific.net/amm.220-223.841.

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A coupled dynamic analysis method is introduced for numerical simulation of floating wind turbine systems in this paper. A numerical code，which has been developed to perform couple hydrodynamic analysis of floating body together with its mooring system, is extended to collaborate with wind turbine simulator to evaluate the interactions between wind turbine and its floating base. To verify the coupled method, a dynamic response analysis of a spar type floating wind turbine system (NREL offshore-5MW baseline wind turbine) is carried out separately by the coupled Morison method and radiation-diffraction theory. Numerical results and comparison are presented. It turns out that this coupled method is competent enough to predict hydrodynamic performance of floating wind turbine system. The numerical results derived in this study may provide crucial information for the design of a floating wind turbine in the near future.

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Neumann, Philipp, Hans-Joachim Bungartz, Miriam Mehl, Tobias Neckel e Tobias Weinzierl. "A Coupled Approach for Fluid Dynamic Problems Using the PDE Framework Peano". Communications in Computational Physics 12, n. 1 (luglio 2012): 65–84. http://dx.doi.org/10.4208/cicp.210910.200611a.

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AbstractWe couple different flow models, i.e. a finite element solver for the Navier-Stokes equations and a Lattice Boltzmann automaton, using the framework Peano as a common base. The new coupling strategy between the meso- and macroscopic solver is presented and validated in a 2D channel flow scenario. The results are in good agreement with theory and results obtained in similar works by Latt et al. In addition, the test scenarios show an improved stability of the coupled method compared to pure Lattice Boltzmann simulations.

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Brencich, Antonio, e Donato Sabia. "Tanaro Bridge: Dynamic Tests on a Couple of Spans". Journal of Bridge Engineering 12, n. 5 (settembre 2007): 662–65. http://dx.doi.org/10.1061/(asce)1084-0702(2007)12:5(662).

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Li, Xiongfei, e Wei Cheng. "Research on Microvibrations Generated by a Control Moment Gyroscope on a Flexible Interface Based on a Dynamic Substructure Method". International Journal of Aerospace Engineering 2018 (2018): 1–17. http://dx.doi.org/10.1155/2018/5045740.

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Microvibrations generated by a control moment gyroscope (CMG) will couple with a flexible spacecraft structure, and this seriously degrades certain point performances of a spacecraft. This study focuses on investigating the coupled microvibrations caused by a CMG on a flexible interface by using a dynamic substructure method (DSM). First, a DSM based on a frequency response function (FRF) is established, and this method is used to simultaneously synthesize multiple substructures with different coordinates irrespective of whether their connection interfaces are rigid or flexible. Second, the bearings and the gimbal servo system are simplified into linear springs, and therefore the CMG model is equivalent to a mass-spring-damping system with eighteen degrees of freedom (DOFs). Third, the established DSM is employed to deduce the FRF matrix of the CMG-flexible interface coupling system that consists of CMG mounted on an aluminum honeycomb sandwich palate (AHSP). Dynamic responses of the coupling system are calculated by the derived FRF matrix. Finally, MATLAB and multibody dynamics simulations are conducted to analyze and validate the dynamic responses of the coupling system obtained by the DSM. The results indicate that the DSM is appropriate to predict the coupled microvibrations of CMG on a flexible interface and exhibits high prediction accuracy and computational efficiency.

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Quinn, Alexander H., Lia P. Bu e Fikile R. Brushett. "Investigation of the Isopropanol-Acetone Redox Couple for Rechargeable Liquid Organic Fuel Cells". ECS Meeting Abstracts MA2022-02, n. 1 (9 ottobre 2022): 18. http://dx.doi.org/10.1149/ma2022-02118mtgabs.

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Electrochemical energy storage can enable decarbonization of the electric grid by stabilizing power delivery from intermittent and unpredictable renewable resources and by extending the operating lifetime of aging grid infrastructure. While many redox chemistries and cell formats have been considered for such purposes, high system cost and emerging application needs motivate the search for new, unconventional redox couples. One such class of molecules are room temperature liquid organic species, which are relatively abundant, inexpensive, chemically stable, energy dense, and, under the right conditions, do not fully oxidize to CO2.1 Due to the inherent stability of these redox couples, in both the oxidized and reduced states, there is a need for selective, durable, and active electrocatalysts to drive the bidirectional electrochemical reactions. Certain electrocatalysts suggest that reversible operation of such couples on a single electrode is possible (e.g., platinum ruthenium (PtRu) alloys facilitate the interconversion of isopropanol and acetone).2 Fundamental studies of the isopropanol/acetone redox couple have demonstrated the selectivity of PtRu alloys and have partially described the reaction mechanism, whereas flow cell studies have primarily focused on improving the galvanic power density (either isopropanol oxidation coupled to oxygen reduction or acetone reduction coupled to hydrogen oxidation).3–5 Yet, to date, studies underemphasize the long-term and dynamic performance of catalysts in these reversible systems, especially under recharging conditions which could significantly alter the catalyst state. Moreover, the electrolyte conditions in ex-situ studies (dilute active species in aqueous acidic electrolyte solutions) do not match those of the fuel cell studies (concentrated active species and ionomer-based solid electrolytes). These discrepancies in the electrocatalyst microenvironment and dynamic operation leave critical questions about catalyst efficacy unaddressed. In this presentation, we explore the isopropanol-acetone redox couple in the context of electrochemically rechargeable liquid organic fuel cells. We focus on electrochemical analyses that assess performance-defining processes on platinic catalysts under acidic conditions. First, we quantify faradaic efficiencies via bulk electrolysis to validate the selectivity and reversibility of the isopropanol/acetone couple, demonstrating the need to separate catalytic and electrocatalytic effects in the presence of oxygen. Then, we employ rotating disk voltammetry in conjunction with surface area quantification methods to estimate intrinsic kinetic reaction rates, which are complicated by dynamic poisoning effects. Thereafter, we focus on characterizing the time-dependent electrocatalyst activity by quantifying decay rates and comparing the poisoning behavior to simple adsorption models. Measurements of these transient changes are anticipated to help predict the performance of electrochemical reactors utilizing aqueous acidic electrolytes and immobilized electrocatalysts, helping bridge fundamental and device studies using techniques that are likely applicable to other water-soluble organic redox couples. Acknowledgements A.H.Q. gratefully acknowledges the National Science Foundation Graduate Research Fellowship Program under Grant Number 1745302. Any opinion, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the NSF. A.H.Q also acknowledges the Alfred P. Sloan Foundation’s Minority Ph.D. (MPHD) Program. References (1) Perry, M. L. ECS Trans. 2021, 104 (1), 23. (2) Perry, M. L.; Yang, Z. J. Electrochem. Soc. 2019, 166 (7), F3268–F3276. (3) Brodt, M.; et al. Energy Technology 2021, n/a (n/a), 2100164. (4) Li, C.; et al. Energies 2018, 11 (10), 2691. (5) Mangoufis-Giasin, I.; et al. Journal of Catalysis 2021, 400, 166–172.

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AYODEJI, OKUBANJO, OKANDEJI ALEXANDER, ALAO PETER, OLALUWOYE OLAWALE, ONAIFO FRANK e MUFUTAU OLAYEMI. "MODEL IDENTIFICATION AND LEVEL CONTROL OF COUPLED TANKS SYSTEM". Journal of Engineering Studies and Research 26, n. 3 (27 luglio 2020): 124–34. http://dx.doi.org/10.29081/jesr.v26i3.214.

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The Couple Tank (CT) system remains as a benchmark to investigate and test new emerging control schemes in the process industry since its dynamic emulates many factual system in the field of process control. In this paper, we examine the performance evaluation of two control algorithms, proportional derivative controller (PD) and proportional-integral-derivative controller (PID). The dynamics of the CT system is experimentally derived by system identification method and validated with a mathematical model that depicts the dynamic behaviour of the coupled tank system. Furthermore, the control schemes are expanded on the model obtained through system identification method. The simulation results showed that the PD controller did not meet all the specified control objectives. To improve the response an integral controller was incorporated to the PD controller and the response was compared to that of the PID controller and uncompensated system. The results revealed that the PID controller satisfied all the control goals. However, the PD controller was more satisfactory in terms of time response criteria.

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Zhedunova, Lyudmila G., e Nikolay N. Posysoev. "The dynamics of experiencing psychological closeness in crisi". Vestnik Yaroslavskogo gosudarstvennogo universiteta im. P. G. Demidova. Seriya gumanitarnye nauki 17, n. 4 (14 dicembre 2023): 612. http://dx.doi.org/10.18255/1996-5648-2023-4-612-619.

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The article discusses the issue of possible dynamics of psychological closeness in the conditions of a long-term psychologically traumatic situation. The results of the empirical study illustrating the presence of gender differences in the experience and perception of intimacy in a couple due to subjective perceptions and personality characteristics of partners. The mechanisms of intimacy formation in the dynamic aspect (before, during and after the crisis) are highlighted. The possibilities of rendering psychological help to a married couple, aimed at working with anxiety in connection with the change and loss of habitual ways of satisfying the needs for jointness and autonomy are considered.

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Herrera de la Cruz, Jorge, e José-Manuel Rey. "Controlling forever love". PLOS ONE 16, n. 12 (29 dicembre 2021): e0260529. http://dx.doi.org/10.1371/journal.pone.0260529.

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A stable and rewarding love relationship is considered a key ingredient for happiness in Western culture. Building a successful long-term relationship can be viewed as a control engineering problem, where the control variable is the effort to be made to keep the relationship alive and well. We introduce a new mathematical model for the effort control problem of a couple in love who wants to stay together forever. The problem can be naturally formulated as a dynamic game in continuous time with nonlinearities. Adopting a dynamic programming approach, a tractable computational formulation of the problem is proposed together with an accompanying algorithm to find numerical solutions of the couple’s effort problem. The computational analysis of the model is used to explore feeling trajectories, effort control paths, happiness, and stabilization mechanisms for different types of successful couples. In particular, the simulation analysis provides insight into the pattern of change of both marital quality and effort making in intact marriages and how they are affected by certain level of heterogamy in the couple.

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Lu, Chenyang, Bentley Turner, Yongsheng Gui, Jacob Burgess, Jiang Xiao e Can-Ming Hu. "An experimental demonstration of level attraction with coupled pendulums". American Journal of Physics 91, n. 8 (1 agosto 2023): 585–94. http://dx.doi.org/10.1119/5.0081906.

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We have experimentally demonstrated dissipative coupling in a double pendulum system through observation, which shows three distinctly different patterns of motion over the accessible parameter space. The described dissipative coupling apparatus is easy to manufacture and budget-friendly. The theoretical calculations are also suitable for the undergraduate level. Our experiment can serve as a novel demonstration for ubiquitous dynamic coupling effects encountered in many disparate physical systems. Unlike the well-known spring-coupled pendulums, our experiment employs Lenz's effect to couple the pendulums through electromagnetic damping, which, to the best of our knowledge, has not been demonstrated in the classroom. Our pendulums exhibit level attraction behaviour between two modes, induced by the dissipative coupling. This stands in contrast to the traditionally taught concept of level repulsion (avoided crossing) with spring-coupled pendulums. This experiment showcases distinctly different time domain dynamics of the dissipatively coupled pendulums over the parameter space, characterized by different oscillation patterns, damping rates, and relative phase between the two pendulums, which is a valuable lesson elucidating the dynamics of synchronization in linear systems for undergraduate students.

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Lin, J.-R. "Static and dynamic behaviours of pure squeeze films in couple stress fluid-lubricated short journal bearings". Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 211, n. 1 (1 gennaio 1997): 29–36. http://dx.doi.org/10.1243/1350650971542291.

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On the basis of microcontinuum theory, this paper theoretically investigates the rheological effects of couple stress fluids on the static and dynamic behaviours of pure squeeze films in journal-bearing systems. The general modified Reynolds equation with no journal rotation is derived by using the Stokes constitutive equations to account for the couple stress effects resulting from lubricants containing additives or suspended particles. The cases of short bearings under a constant applied load and an alternating load are analysed. The solutions for film pressure in a closed form are shown, from which the squeeze film characteristics are determined. According to the results evaluated, the effects of couple stresses significantly increase the film pressure and then the load-carrying capacity is compared with the Newtonian lubricant case. Under a cyclic load the couple stress effects provide a reduction in the velocity of the journal centre as well as an increase in the minimum permissible height of the squeeze film. As a consequence, the bearing with a couple stress fluid as the lubricant improves the squeeze film characteristics and results in a longer bearing life.

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Déprez, Pascal, Philippe Hivart, Jean François Coutouly e Etienne Debarre. "Friction and Wear Studies Using Taguchi Method: Application to the Characterization of Carbon-Silicon Carbide Tribological Couples of Automotive Water Pump Seals". Advances in Materials Science and Engineering 2009 (2009): 1–10. http://dx.doi.org/10.1155/2009/830476.

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An experimental design based on the Taguchi method has been applied to optimize the use of a dynamic sealing element of water pump of automotives combustion engines. A carbon primary ring and a silicon carbide mating ring set up this dynamic sealing element. The aim of this work was to experimentally determine the crossed influence of the primary ring variant, the normal load, the surrounding, the mating ring finishing, and the rotational frequency on the dynamic friction coefficient and on the wear of carbon primary ring-silicon carbide mating ring tribological couples. The coefficient of dynamic friction and the wear depend on the design factors. They are also functions of the interactions between these experimental factors, from the implementation of an experimental design. The results obtained allow the optimal functioning condition to be determined and the best friction couple to be used for a given dynamic sealing application.

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Qin, Tao, Kai Yun Zhang e Hong Lei Liu. "The Comparative Study on the Gassy Coal Thermal-Fluid-Solid Coupling and no Coupling". Advanced Materials Research 1010-1012 (agosto 2014): 1494–97. http://dx.doi.org/10.4028/www.scientific.net/amr.1010-1012.1494.

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In order to study the mechanism of dynamic disaster on gassy coal and realize the monitoring and prediction, with the Didao mine as an example, this paper set up the thermal fluid-solid three field couple mathematical models of driving face and comparative analyzed the mathematical models between couple and not couple by using the software comsol. The study result shows that it has a swift response, a close connection and a shorter time in the formation of o-ring, when it is the thermal fluid-solid three field couple.

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Satish C Sharma, Nathi Ram Chauhan, Manish Saraswat e Rahul Kumar. "Theoretical Analysis of Orifice Compensated Symmetric and Asymmetric Hydrostatic Non-Recessedjournal Bearings Under Couple Stress Lubricants". International Journal of Maritime Engineering 1, n. 1 (27 luglio 2024): 97–102. http://dx.doi.org/10.5750/ijme.v1i1.1341.

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Abstract (sommario):

In this research a hole-entry hydrostatic journal bearings with couple stress and Newtonian lubricants have been examined analytically. The Newton Rapshon Method and Finite Element Method have been applied on Reynolds equation for couple stress and for the Newtonian lubricants to achieve the film pressure. The results of disparate factors of couple stress lubricants and the external load have been modeled. The outcome of the achieved results showed that the static and dynamic actions of bearings enhanced under a couple stress lubricants assessed the bearings performance with Newtonian lubricant.

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Xiong, Shaoping, Gabriel Wilfong e John Lumkes. "Development of a novel high-speed actuation mechanism using a magneto-rheological fluid clutch and its application to a fluid control valve". Journal of Intelligent Material Systems and Structures 30, n. 16 (28 luglio 2019): 2502–16. http://dx.doi.org/10.1177/1045389x19862368.

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In many dynamic systems, such as vehicles, engine air and fuel control systems, fluid power systems, industrial robotics, and testing machines, high-speed actuators are necessary to achieve efficient system operation and high bandwidth performance. This article introduces a new actuation mechanism to enable high-speed actuation. The premise for this actuation mechanism is to momentarily couple a moving component (kinetic energy source) with translational components, which is enabled by a coupling/clutch system. The kinetic energy source (flywheel, electric motor, pump or motor shaft, etc.) is intermittently clutched and declutched to produce linear motion. This article presents such an energy coupler actuator using a magneto-rheological fluid clutch, initially focused on an application for high-speed valve actuation. A multi-physics coupled model was developed to evaluate the proposed energy coupler actuator performance. Simulations were conducted to optimize the energy coupler actuator design parameters. A prototype of the magneto-rheological fluid energy coupler actuator based on the optimal design solution was fabricated and experimentally tested, which achieved 1.6-mm stroke in 4.7 ms.

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Volkov, Vladimir A., Paula M. Grissom, Vladimir K. Arzhanik, Anatoly V. Zaytsev, Kutralanathan Renganathan, Tristan McClure-Begley, William M. Old, Natalie Ahn e J. Richard McIntosh. "Centromere protein F includes two sites that couple efficiently to depolymerizing microtubules". Journal of Cell Biology 209, n. 6 (22 giugno 2015): 813–28. http://dx.doi.org/10.1083/jcb.201408083.

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Firm attachments between kinetochores and dynamic spindle microtubules (MTs) are important for accurate chromosome segregation. Centromere protein F (CENP-F) has been shown to include two MT-binding domains, so it may participate in this key mitotic process. Here, we show that the N-terminal MT-binding domain of CENP-F prefers curled oligomers of tubulin relative to MT walls by approximately fivefold, suggesting that it may contribute to the firm bonds between kinetochores and the flared plus ends of dynamic MTs. A polypeptide from CENP-F’s C terminus also bound MTs, and either protein fragment diffused on a stable MT wall. They also followed the ends of dynamic MTs as they shortened. When either fragment was coupled to a microbead, the force it could transduce from a shortening MT averaged 3–5 pN but could exceed 10 pN, identifying CENP-F as a highly effective coupler to shortening MTs.

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Ji, Lianghao, Yue Zhang e Yiliu Jiang. "Couple-Group Consensus: A Class of Delayed Heterogeneous Multiagent Systems in Competitive Networks". Complexity 2018 (3 ottobre 2018): 1–11. http://dx.doi.org/10.1155/2018/7386729.

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This paper discusses the couple-group consensus issues of a class of heterogeneous multiagent systems containing first-order and second-order dynamic agents under the influence of both input and communication delays. In distinction to the existing works, a novel distributed coordination control protocol is proposed which is not only on the foundation of the competitive interaction between the agents but also has no virtual velocity estimation in the first-order dynamics. Furthermore, without the restrictive assumptions existing commonly in the related works, several sufficient algebraic criteria are established for the heterogeneous systems to realize couple-group consensus asymptotically. The obtained conclusions show that the achievement of the systems’ couple-group consensus intimately relates to the coupling weights between the agents, the systems control parameters, and the input time delays of the agents, while communication time delays between the agents are irrelevant to it. Finally, several simulations are illustrated to verify the effectiveness of the obtained theoretical results.

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Henry, Timothy J., Scott M. Lephart, Jorge Giraldo, David Stone e Freddie H. Fu. "The Effect of Muscle Fatigue on Muscle Force-Couple Activation of the Shoulder". Journal of Sport Rehabilitation 10, n. 4 (novembre 2001): 246–56. http://dx.doi.org/10.1123/jsr.10.4.246.

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Context:Muscle fatigue is an important concept in regard to the muscle function of the shoulder joint. Its effect on the muscle force couples of the glenohumeral joint has not been fully identified.Objective:To examine the effects of muscle fatigue on muscle force-couple activation in the normal shoulder.Design:Pretest, posttest.Patients:Ten male subjects, age 18–30 years, with no previous history of shoulder problems.Main Outcome Measures:EMG (area) values were assessed for the anterior and middle deltoid, subscapularis, and infraspinatus muscles during 4 dynamic stabilizing exercises before and after muscle fatigue. The exercises examined were a push-up, horizontal abduction, segmental stabilization, and rotational movement on a slide board.Results:No significant differences were observed for any of the muscles tested.Conclusions:The results of our study indicate that force-couple coactivation of the glenohumeral joint is not significantly altered after muscle fatigue.

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Urban, Maximilian J., Chao Zhou, Xiaoyang Duan e Na Liu. "Optically Resolving the Dynamic Walking of a Plasmonic Walker Couple". Nano Letters 15, n. 12 (18 novembre 2015): 8392–96. http://dx.doi.org/10.1021/acs.nanolett.5b04270.

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41

Nazemi, Maryam, Mojtaba Amiri Majd, Mohammad Ghamari e Masoud Asadi. "Qualitative comparison of satisfactory stable marriages and marriages with dissatisfaction in infertile couples". Journal of Adolescent and Youth Psychological Studies 4, n. 7 (2023): 1–13. http://dx.doi.org/10.61838/kman.jayps.4.7.1.

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Background and Aim: The aim of this study was to compare the quality of satisfactory stable marriage and dissatisfaction-associated marriages in infertile couples. Methods: This study was conducted using a qualitative method using the grounded theory method. Using purposeful sampling method, participants were selected according to inclusion criteria and finally 18 infertile couples with satisfactory and stable marriage and 15 infertile couples in marriage with dissatisfaction were interviewed semi-structured and the data were analyzed using Colaizzi's method. Results: The result of open coding was reaching 202 primary codes, 84 sub-categories and 8 main categories and one central category. The central issue in this study is infertility: a dynamic for experiencing genuine and committed love in marriage or its dissatisfaction and disintegration. Data analysis showed that protective and risk factors affecting satisfactory stable marriage and couples with dissatisfaction were defined in three areas of intrapersonal factors, interpersonal and couple factors and factors related to family system. Conclusion: According to the results of this study, achieving acceptance of infertility and the experience of genuine and committed love in marriage or its dissatisfaction and collapse is not accidental in infertile couples, but by choosing constructive and active action or using ineffective strategies created and is an individual, family and interactive process that infertile couples can make with conscious efforts to grow and transcend marriage and take care of it, companionship, couple unity and acquisition. Couple skills and efficient strategies for health and happiness and finally gain satisfaction and stability in marriage and prevent dissatisfaction and breakdown of their marriage.

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Ni, Cynthia, Christina V. Dinh e Kristala L. J. Prather. "Dynamic Control of Metabolism". Annual Review of Chemical and Biomolecular Engineering 12, n. 1 (7 giugno 2021): 519–41. http://dx.doi.org/10.1146/annurev-chembioeng-091720-125738.

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Abstract (sommario):

Metabolic engineering reprograms cells to synthesize value-added products. In doing so, endogenous genes are altered and heterologous genes can be introduced to achieve the necessary enzymatic reactions. Dynamic regulation of metabolic flux is a powerful control scheme to alleviate and overcome the competing cellular objectives that arise from the introduction of these production pathways. This review explores dynamic regulation strategies that have demonstrated significant production benefits by targeting the metabolic node corresponding to a specific challenge. We summarize the stimulus-responsive control circuits employed in these strategies that determine the criterion for actuating a dynamic response and then examine the points of control that couple the stimulus-responsive circuit to a shift in metabolic flux.

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Naduvinamani, Neminath, e Ashwini Angadi. "Static and Dynamic Characteristics of Rough Porous Rayleigh Step Bearing Lubricated with Couple Stress Fluid". Lubricants 10, n. 10 (13 ottobre 2022): 257. http://dx.doi.org/10.3390/lubricants10100257.

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Abstract (sommario):

In tribology, the Rayleigh step bearing has the maximum load capacity of any feasible bearing geometry. Traditional tribology resources have demonstrated that the Rayleigh step has an ideal geometry which maximizes load capacity. Both in nature and technology, rough and textured surfaces are essential for lubrication. While surface roughness enhances the performance of the bearings as an efficiency measure, it still has a significant impact on the load-carrying capacity of the bearing. In the present study, we investigate the dynamic characteristics of the Rayleigh step bearing with the impact of surface roughness and a porous medium by considering a squeezing action. Couple stress fluid is considered a lubricant with additives in both the film as well as the porous region. Based on Stokes constitutive equations for couple stress fluids, Darcy’s law for porous medium, and stochastic theory for rough surfaces, the averaged Reynolds-type equation is derived. Expressions are obtained for the volume flow rate, steady-state characteristics, and dynamic characteristics. The influence of surface roughness and the porous medium on the Rayleigh step bearing is analyzed. We investigated the static and dynamic characteristics of the Rayleigh step bearing. As a result, the couple stress fluid increases (decreases) the steady load-carrying capacity, dynamic stiffness, and dynamic damping coefficients, and decreases (increases) the volume flow rate negatively (positively) skewed roughness in comparison with that of the Newtonian case. The results are compared with those of the smooth case.

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Montoya, Marvin, Juan Genesca e Rodrigo Montoya. "The AA7075–CS1018 Galvanic Couple under Evaporating Droplets". Corrosion and Materials Degradation 5, n. 1 (7 marzo 2024): 92–108. http://dx.doi.org/10.3390/cmd5010005.

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The galvanic corrosion behavior of the AA7075–CS1018 couple was examined in dynamic electrolytes using the ZRA technique. A modified electrochemical setup was developed to support the use of thin-film gel and liquid electrolytes on metallic surfaces. This allowed the collection of chemical information, left behind by the liquid electrolyte during evaporation, through a thin-film gel. The analysis of the gel electrolyte film confirmed the acidification on AA7075 and the alkalinization on CS1018 but also offered novel insights on their dependence on the galvanic current. The galvanic current was proportional to the initial NaCl concentration in the range of 0.01 to 0.06 M. However, due to continuous evaporation, the NaCl concentration increased, limiting oxygen diffusion and decreasing the galvanic current, especially for electrolytes exceeding 0.06 M. The galvanic current was determined by considering the dynamic evolution (caused by the evaporation of the electrolyte film) of both the thickness of the electrolyte and its concentration.

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Park, Jong-Hwan, e Nam-Soon Choi. "A Study on the Effect of Using Art Therapy Programs to Promote Couples' Relationship and Communication, on Couples' Conflict and Happiness". Korean Association For Learner-Centered Curriculum And Instruction 22, n. 23 (15 dicembre 2022): 89–113. http://dx.doi.org/10.22251/jlcci.2022.22.23.89.

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Abstract (sommario):

Objectives Purpose This study attempted to investigate the effect of art therapy programs to promote marital relationships and communication, marital conflict resolution, and happiness. The purpose of the art therapy program was to naturally express one's inner feelings, understand and accept oneself and others, and to verify the effect on enhancing marital relations and communication by making positive changes. Methods Data were collected from January 1 to June 30, 2021 for the couple of members of the Cultural Center in N city. After confirming the research purpose and program composition, 16 couples who expressed their willingness to participate voluntarily were selected, and 8 pairs were wirelessly composed of experimental groups and 8 pairs were composed of control groups. For this study, a couple interaction scale, a couple communication scale, a couple conflict scale, and a happiness scale were used, and a dynamic house-tree-person picture test was conducted. The independent sample t-test and the corresponding sample t-test were statistically analyzed using SPSSWIN 25.0, and 22-verification and covariance verification (ANCOVA) were performed. In addition, the qualitative research method was introduced, and the interviews with participants and activity memo information were used to analyze them with Colaizzi's phenomenological research method. Results As a result of the study, it was verified that the couple art therapy program was effective in enhancing marital relations and communication. In the process of couples exploring themselves, expressing their thoughts, and expressing their suppressed feelings through art activities, their understanding of themselves and their spouses increased, and sincere communication served as an opportunity to resolve conflicts between couples and realize their willingness to change for each other. As a result, it was found that the improvement of the relationship and satisfaction between couples can be the basis for determining the happiness of couples. Conclusions This study is a study that introduced qualitative research after focusing on quantitative research. For this study, the reconstructed art therapy program was operated, and the marital interaction scale, marital communication scale, marital conflict scale, and happiness scale were conducted before and after the marital art therapy program. As a result, it was found to be significant in the effectiveness test of the couple art therapy program, and it was statistically significant in marital interaction, marital communication, marital conflict, and marital happiness scale. In this regard, it was also found to be high satisfaction in program satisfaction. These significant results showed that even in the analysis of the introduced qualitative research, sincere communication between couples was the willingness to increase understanding between couples, resolve conflicts, and change between couples.

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Ni, Shao Bo, Wei Jun Hu e Song Xiong. "Research of De-Couple Control System for near Space Vehicle with High Maneuver and Couple". Applied Mechanics and Materials 128-129 (ottobre 2011): 979–84. http://dx.doi.org/10.4028/www.scientific.net/amm.128-129.979.

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A de-couple control method with information feedback from other control channel and a method with double control loops were present for the hypersonic vehicle with non-linear, couple and lateral maneuver. The whole controller was divided into two parts: the computation of actuator which deal with control couple and design of control law which solve the problem of movement and aerodynamic couple. The time-varying controller parameter method and robust control law were present to solve the problem of quick time-varying model parameter and non-linear. Finally these two methods were analyzed contrastively; the simulation result show that these two methods present above can achieve the quick dynamic and high precise track of command. But the latter was better.

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BASHA, SHAIK AKBAR, e DEBASISH SARKAR. "COMPETITIVE LIFE TIME ASSESSMENT OF SrO-ZTA/SrO-ZTA AND CoCrMo/UHMWPE HIP PROSTHESIS BEARINGS". Journal of Mechanics in Medicine and Biology 20, n. 03 (aprile 2020): 2050009. http://dx.doi.org/10.1142/s0219519420500098.

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The hip joint envisages the prime load bearing structure among other joints in the human body. Hip joint failure leads to the replacement of the hip joint prosthesis. This research work focuses on the proper selection of bearing couple materials for the hip joint to improve the performance and life. Herein, the stress and deformation of different bearing couple materials are analysed in the perspective of transient dynamic analysis under jogging load cycle. Selective hip joint bearing (femoral head-liner) couples are SS316L on UHMWPE (MoP), CoCrMo on UHMWPE (MoP), Ti6Al4V on SrO-ZTA (MoC), SrO-ZTA on UHMWPE (CoP) and SrO-ZTA on SrO-ZTA (CoC) encountered, respectively. The SrO-ZTA on SrO-ZTA (CoC) bearing couple generates the less Von Mises stress of 180.88 MPa. Load bearing pressure and Archard law predict the wear depth of CoCrMo on UHMWPE (MoP) and SrO-ZTA on SrO-ZTA (CoC) bearing couples are 0.141 mm/year and 0.031 mm/year, respectively. In simultaneous, the theoretical wear volume for CoCrMo on UHMWPE (MoP) and SrO-ZTA on SrO-ZTA (CoC) bearing couples are found as 35.46[Formula: see text]mm3/year and 2.62[Formula: see text]mm3/year, respectively. The wear depth and wear volume are supporting the available clinical retrievals and exist in well acceptable range. Competitive wear analysis data ensures 15 years safe life of SrO-ZTA on SrO-ZTA (CoC) hip prosthesis bearing.

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Kumar, Ashutosh, e SK Kakoty. "Effect of couple stress parameter on steady-state and dynamic characteristics of three-lobe journal bearing operating on TiO2 nanolubricant". Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 234, n. 4 (27 luglio 2019): 528–40. http://dx.doi.org/10.1177/1350650119866028.

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Steady-state and dynamic performance parameters of three-lobe fluid film bearing, operating on TiO2 nanolubricant have been obtained. The effective viscosity for a given volume fraction of TiO2 nanoparticle in base fluid is obtained by using Krieger–Dougherty viscosity model. Various bearing performance parameters are obtained by solving remodeled Reynolds equation, which includes couple stress parameter. The stiffness and damping coefficients are also obtained for different values of the couple stress parameter. Results show a significant rise in the nondimensional load-carrying capacity and flow coefficient while there is a decrease in friction variable. It also reveals a significant improvement in the dynamic coefficient of bearing.

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Zheng, Tianyi, Wuhao Yang, Jie Sun, Xingyin Xiong, Zheng Wang, Zhitian Li e Xudong Zou. "Enhancing Performance of Reservoir Computing System Based on Coupled MEMS Resonators". Sensors 21, n. 9 (23 aprile 2021): 2961. http://dx.doi.org/10.3390/s21092961.

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Reservoir computing (RC) is an attractive paradigm of a recurrent neural network (RNN) architecture, owning to the ease of training and existing neuromorphic implementation. Its simulated performance matches other digital algorithms on a series of benchmarking tasks, such as prediction tasks and classification tasks. In this article, we propose a novel RC structure based on the coupled MEMS resonators with the enhanced dynamic richness to optimize the performance of the RC system both on the system level and data set level. Moreover, we first put forward that the dynamic richness of RC comprises linear dynamic richness and nonlinear dynamic richness, which can be enhanced by adding delayed feedbacks and nonlinear nodes, respectively. In order to set forth this point, we compare three typical RC structures, a single-nonlinearity RC structure with single-feedback, a single-nonlinearity RC structure with double-feedbacks, and the couple-nonlinearity RC structure with double-feedbacks. Specifically, four different tasks are enumerated to verify the performance of the three RC structures, and the results show the enhanced dynamic richness by adding delayed feedbacks and nonlinear nodes. These results prove that coupled MEMS resonators offer an interesting platform to implement a complex computing paradigm leveraging their rich dynamical features.

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Hur, Chihoon, Carlos Ferreira e Gerard Schepers. "Applicability of Dynamic Inflow Models of HAWT in Yawed Flow Conditions". Energies 15, n. 24 (10 dicembre 2022): 9368. http://dx.doi.org/10.3390/en15249368.

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Horizontal axis wind turbines (HAWTs) experience yaw misalignments due to the physical limitations of yaw controllers and various novel active yaw controls. Moreover, the motion of floating offshore wind turbines (FOWTs) accelerates yaw misalignment. The blade element momentum (BEM) method is widely used due to its computational efficiency for the design of HAWTs. Momentum theory, the basis of BEM, assumes steady flow and uniform induction field at the disc. Those assumptions are relaxed by engineering models to capture yaw and unsteady effects. Current yaw engineering models, however, are inaccurate since they do not capture the asymmetric wake expansion effect. Dynamic inflow models have been developed for non-yawed flow. Furthermore, the AVATAR project shows that BEM using fully coupled engineering models, the current yaw, dynamic inflow and various engineering models, suffers from significant deficiencies. This purpose of this paper, therefore, is to investigate dynamic effects for yawed flow, and determine if current dynamic inflow models are applicable in yawed conditions. The Glauert’s modified momentum theory is applied to dynamic inflow models to couple the two models. Among all coupled models, Øye, Yu PWVM and Yu FWVM DIM can capture asymmetric trends. However, the results show the significant deficiencies in phase delay on the actuator disc.

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