Search results for "reversibility"
showing 7 items of 17 documents
Coupled systems of non-smooth differential equations
2012
Abstract We study the geometric qualitative behavior of a class of discontinuous vector fields in four dimensions. Explicit existence conditions of one-parameter families of periodic orbits for models involving two coupled relay systems are given. We derive existence conditions of one-parameter families of periodic solutions of systems of two second order non-smooth differential equations. We also study the persistence of such periodic orbits in the case of analytic perturbations of our relay systems. These results can be seen as analogous to the Lyapunov Centre Theorem.
Modelling Reverse Electrodialysis process via Exergy Analysis
2017
Salinity Gradient Power Heat Engines (SGP-HEs) represent a novel technology to convert low grade waste heat into electricity. Reverse Electrodialysis Heat Engine (REDHE) is one of the possible application of this concept, where a common RED unit is coupled with a thermal regeneration unit supplied with waste heat to restore the salinity gradient of the streams to be fed back to the RED unit. In a RED unit, anion and cation exchange membranes (AEMs and CEMs) are alternatively stacked and interposed between salt solutions at different concentration generating an electric potential difference over each membrane along with a selective transport of cations and anions from the concentrated soluti…
Lung Function Decline in Adult Asthmatics—A 10-Year Follow-Up Retrospective and Prospective Study
2021
Asthma may have an impact on lung function decline but conflicting results are reported in forced expiratory volume in one second (FEV1) decline. We aimed to describe the changes in FEV1 in lifelong non-smoking adult asthmatic outpatients during a 10-year follow-up comparing years 1–5 (1st period) with years 6–10 (2nd period) to assess factors affecting these changes. A total of 100 outpatients performed spirometry every 3 months during a 10-year survey. FEV1/Ht3 slope values of the 2nd period reduced significantly respect to the 1st period (p 1 slopes of years 1–5 and 6–10 were inversely associated with FEV1 at enrolment (p = 0.02, p = 0.01, respectively). Reversibility and variability FEV…
On the analysis of a random walk-jump chain with tree-based transitions and its applications to faulty dichotomous search
2018
Random Walks (RWs) have been extensively studied for more than a century [1]. These walks have traditionally been on a line, and the generalizations for two and three dimensions, have been by extending the random steps to the corresponding neighboring positions in one or many of the dimensions. Among the most popular RWs on a line are the various models for birth and death processes, renewal processes and the gambler’s ruin problem. All of these RWs operate “on a discretized line”, and the walk is achieved by performing small steps to the current-state’s neighbor states. Indeed, it is this neighbor-step motion that renders their analyses tractable. When some of the transitions are to non-ne…
Optical Symmetry of Ferroelectric Liquid Crystal Cells
1990
We observe an exact optical symmetry in Surface Stabilized Ferroelectric Liquid Crystal (SSFLC) cells in polarized transmission optical microscopy and spectroscopy. A theoretical argument based on the intrinsic time reversibility of Maxwell's equations and energy conservation is developed to explain this symmetry. The results support the model of Clark and Rieker for zig-zag wall structure and illustrate the necessity of including the orientational binding of the director at the chevron interface.
Controlling Oxidative Addition and Reductive Elimination at Tin(I) via Hemi-Lability.
2021
We report on the synthesis of a distannyne supported by a pincer ligand bearing pendant amine donors that is capable of reversibly activating E–H bonds at one or both of the tin centres through dissociation of the hemi-labile N–Sn donor/acceptor interactions. This chemistry can be exploited to sequentially (and reversibly) assemble mixed-valence chains of tin atoms of the type ArSn{Sn(Ar)H} n SnAr ( n = 1, 2). The experimentally observed (decreasing) propensity towards chain growth with increasing chain length can be rationalized both thermodynamically and kinetically by the electron-withdrawing properties of the –Sn(Ar)H– backbone units generated via oxidative addition. peerReviewed
Explicit proton transfer in classical molecular dynamics simulations.
2014
We present Hydrogen Dynamics (HYDYN), a method that allows explicit proton transfer in classical force field molecular dynamics simulations at thermodynamic equilibrium. HYDYN reproduces the characteristic properties of the excess proton in water, from the special pair dance, to the continuous fluctuation between the limiting Eigen and Zundel complexes, and the water reorientation beyond the first solvation layer. Advantages of HYDYN with respect to existing methods are computational efficiency, microscopic reversibility, and easy parameterization for any force field peerReviewed