Degree Of Irreversibility Research Articles

Generalized golden mean and the efficiency of thermal machines

We investigate generic heat engines and refrigerators operating between two heat reservoirs, for the condition when their efficiencies are equal to each other. It is shown that the corresponding value of efficiency is given as the inverse of the generalized golden mean, ϕp, where the parameter p depends on the degrees of irreversibility of both engine and refrigerator. The reversible case (p = 1) yields the efficiency in terms of the standard golden mean. We also extend the analysis to a three-heat-reservoir setup.

Assessing the role of initial correlations in the entropy production rate for nonequilibrium harmonic dynamics

Entropy production provides a general way to state the second law of thermodynamics for non-equilibrium scenarios. In open quantum system dynamics, it also serves as a useful quantifier of the degree of irreversibility. In this work we shed light on the relation between correlations, initial preparation of the system and non-Markovianity by studying a system of two harmonic oscillators independently interacting with their local baths. Their dynamics, described by a time-local master equation, is solved to show - both numerically and analytically - that the global purity of the initial state of the system influences the behaviour of the entropy production rate and that the latter depends algebraically on the entanglement that characterise the initial state.

On the Degree of Irreversibility of Friction in Sheared Soft Adhesive Contacts

A number of authors have experimentally assessed the influence of friction on adhesive contacts, and generally the contact area has been found to decrease due to tangential shear stresses at the interface. The decrease is however generally much smaller than that predicted already by the Savkoor and Briggs 1977 classical theory using “brittle” fracture mechanics mixed mode model extending the JKR (Griffith like) solution to the contact problem. The Savkoor and Briggs theory has two strong assumptions, namely that (i) shear tractions are also singular at the interface, whereas they have been found to follow a rather constant distribution, and that (ii) no dissipation occurs in the contact. While assumption (ii) has been extensively discussed in the Literature the role of assumption (i) remained unclear. We show that assuming entirely reversible slip at the interface with a constant shear stress fracture mechanics model leads to results almost indistinguishable from the Savkoor and Briggs model (and further in disagreement with experiments), hence it is assumption (ii) that critically affects the results. We analyze a large set of experimental data from Literature and show that the degree of irreversibility of friction can vary by orders of magnitude, despite similar materials and geometries, depending on the velocity at which the tangential load is applied.

Effects of pre, post, and simultaneous loading of natural organic matter on 2-methylisoborneol adsorption on superfine powdered activated carbon: Reversibility and external pore-blocking

Three different natural organic matter (NOM)-loading methods were compared for the adsorptive removal of 2-methylisoborneol (MIB) by superfine powdered activated carbon (SPAC) and conventionally-sized powdered activated carbon (PAC). The three NOM-loading methods were: NOM adsorption followed by MIB (MIB adsorption on NOM-preloaded carbon), MIB adsorption followed by NOM (MIB adsorption on NOM post-loaded carbon), and simultaneous NOM and MIB loading (MIB adsorption on NOM-simultaneously loaded carbon). MIB removals were similar for the smaller-sized carbon (SPAC) at higher AC dosages and at lower initial NOM concentrations. The similar MIB removals indicate direct site competition between MIB and NOM with MIB adsorption reversibility (complete desorption of MIB by NOM). At lower AC doses, especially for PACs, and at higher initial NOM concentrations, the adsorption of MIBs depended on the sequence of MIB or NOM adsorption. MIB removal was lowest for the NOM-preloaded carbon, followed by NOM-simultaneously loaded carbon. The highest MIB removal was achieved by post-loading of NOM, indicating that the adsorption is irreversible. MIB adsorption on SPAC was more reversible than on PAC, although the pore size distributions of the two carbons were similar. The high degree of adsorption irreversibility for PAC compared with SPAC indicated that pore blocking occurs due to NOM loading at the PAC particle surface. Images of the external adsorption were obtained using isotope mapping and 15N-labeled effluent organic matter.

The Valuation of Urban Land: Comparison and Critique of Three CAMA Methods

We present new methods for urban land valuation based on a high degree of irreversibility given that a substantial structure is present on the land. Irreversibility implies that land and structure value function as a whole until the option to tear down and redevelop becomes valuable. In a typical situation, where structures are far from teardown, irreversibility implies that land and structure value change at about the same rate over time. Land valuation methods based on irreversibility are compared to valuations based on vacant land sales and on land residual methods (land value equals property value minus the depreciated cost to build); both methods predict that land value is much more volatile than structure value whereas irreversibility implies a more stable ratio of land value to property value. We fit all three methods to Maricopa County assessor data during a recovery period (2012-2018). Results show that the land value ratio behaves as predicted by irreversibility, not by the land residual or vacant land methods. We suggest new mass assessment procedures based on the value of the option to redevelop. We provide evidence that our procedures merit further study.

Exergetic Analysis of a Refrigeration System with Mechanical Vapors Compression

The main purpose of this study is to improve the energy efficiency of a refrigerated facility by means of exergetic analysis. In order to achieve this goal, we have evaluated the input exergy flows of the whole system to deduce the exergetic yields, which are compared to the degree of irreversibility in order to have a qualitative measurement of energy losses. The concept of exergy is the part of energy that is virtually converted into work. The exergetic analysis was performed on a refrigeration unit ZR22K3E Copeland Scroll. The results of this analysis are consistent with the condition, that the exergetic performance, which is: 36.57% and it is approximately equal to the degree of irreversibility which is 37.50%. This approach provides a comprehensive, standard and rigorous framework for the analysis of energy systems, and thus for the understanding and systemic management of the energy challenge.

Laminin-modified gellan gum hydrogels loaded with the nerve growth factor to enhance the proliferation and differentiation of neuronal stem cells.

The reconstruction of peripheral nerves has lately received great attention as many patients suffer from peripheral nerve injury every year around the world. However, the damage to human nerve cells has different degrees of irreversibility due to a slow growth speed and low adhesion with the surrounding tissues. In an effort to overcome this challenge, we applied novel laminin (LN)-modified thiolated gellan gum (TGG) and loaded the nerve growth factor (NGF) as a tissue engineering scaffold for facilitating neuronal stem cell proliferation via a synergy effect for the ERK–MAPK pathway. TGG was characterized by 1H NMR spectroscopy and scanning electron microscopy, and its rheological behavior was also studied. The NGF release curve fitted the Korsmeyer–Peppas model and belonged to a Fickian diffusion-controlled release mechanism. The neuronal stem cells from newborn SD rats could adhere tightly and proliferate at a relatively rapid speed, showing excellent biocompatibility and the ability to promote growth in the modified TGG. LN and NGF could decrease the apoptosis effects of neuronal stem cells, as shown via the flow cytometry results. In a three-dimensional culture environment, LN and NGF could facilitate neuronal stem cells to differentiate into neurons, as proved by immunofluorescence, q-PCR, and western blot analyses. Therefore, the rational design of the TGG gel loaded with NGF has promising applications in the reconstruction of peripheral nerves.

The study of activation impact during formation and testing of Ni(OH)2 electrochromic films in the presence of Al3+ and WO42- ions

The present study is devoted to an attempt to improve the characteristics of nickel hydroxide electrochromic films. The study of optical and electrochemical characteristics of the films, prepared through the codeposition of nickel and aluminum and additional modification during the cycling of the prepared samples was conducted. The modification was realized through the cycling of films in the solution of potassium hydroxide with small amounts of potassium tungstate. Over the course of the study, a series of films were obtained, which demonstrated different electrochemical and optical behavior. Thus, it was found that both the deposition method and the cycling regime have a significant effect on the characteristics of electrochromic films. It is shown that for the potentiodynamic regime, the best characteristics were demonstrated by the film without modifications or additives. On the other hand, all modified films, codeposited with aluminum, demonstrated better characteristics in galvanostatic regimes over the reference film. It would appear that this is due to the physico-chemical features of the films deposited in the presence of additives. In turn, the use of high-rate cycling regime leads to a decrease of electrochromic characteristics, namely higher degree of irreversibility. Despite the difference of currents in different galvanostatic regimes by 4 times, the coloration degree did not differ much. It was also found that the presence of 0.3 mM potassium tungstate in the cycling electrolyte resulted in a significant decrease in the electrochromic properties of the samples

The Burden of the National Debt: Evidence from Mergers and Acquisitions

We examine the impact of changes in national debt on the mergers and acquisitions (M&As) activity. Although increases in government debt reduces the acquisition likelihood, we find no evidence for the traditional interest rate mechanism. Instead, we document that upsurges in national debt depress M&A activity through increases in fiscal policy related uncertainty (taxes, discretionary spending, entitlement programs etc.). During periods of increasing national debt, acquirers decrease stock-based financing relative to cash-based financing and reduce the acquisition of targets with a higher degree of investment irreversibility. In such periods, announced deals are associated with lower premiums and lower synergistic gains.

Tracking Battery Swelling in Uncompressed Li-Ion Cells Via in-Operando X-Ray Radiography and Micro-Tomography

Li-ion battery swelling during cycling is known to be a major cause of battery electrode degradation and can contribute significantly to cell failure [1,2]. The main cause of battery swelling is due to the intercalation of Li into the carbon and LiCoO2 electrodes. This swelling is known to occur anisotropically due to the electric field and Li salt distributions in the electrode [3]. We have used x-ray radiography and µCT to map this swelling, in-operando under charge and discharge conditions, in the layers of an uncompressed Li-ion battery. This study gives insight into the relationship between the battery state of charge and the electrode swelling. The change in swelling due to the electrode geometry is also investigated. Li-ion pouch cells were cycled at 0.5, 1 and 2 C while undergoing x-ray radiography and tomography at the BMIT beamline of the Canadian Light Source. Synchrotron radiography allowed the tracking of the electrode swelling in two dimensions with high temporal (10 s/frame) and spatial resolution (3 µm/pixel). µCT measurements of Li-ion cells were carried out under the same battery cycling conditions and scans were taken at 0, 25, 75 and 100 % state of charge (3 µm/pixel, 225 s/scan). Reconstruction and segmentation of the collected images allowed for the measurement of each electrode volume. From these results it appears that electrode swelling depends on a number of factors, including electrode geometry, charge/discharge rate and battery age. There is also a noticeable degree of irreversibility in the swelling of the electrode, which may be a possible metric for battery degradation. The quantification of the carbon electrode swelling corresponds closely with the theoretical value for lithium intercalation to LiC6, although there is a discrepancy between the swelling value obtained for the LiCoO2 electrode and theory. These results give a valuable insight into the mechanical dynamics of Li-ion batteries under in-operando conditions and will provide validation to, and data for, battery models including stress-strain and degradation models. References Bond, T., Zhou, J., & Cutler, J. (2017). Electrode Stack Geometry Changes during Gas Evolution in Pouch-Cell-Type Lithium Ion Batteries. Journal of The Electrochemical Society, 164(1), A6158–A6162.Chen, C., Wei, Y., Zhao, Z., Zou, Y., & Luo, D. (2019). Investigation of the swelling failure of lithium-ion battery packs at low temperatures using 2D/3D X-ray computed tomography. Electrochimica Acta, 305, 65–71.Zhang, N., & Tang, H. (2012). Dissecting anode swelling in commercial lithium-ion batteries. Journal of Power Sources, 218, 52–55. Figure 1 (a) 2D x-ray radiography of a Li-ion pouch cell and (b) 3D reconstruction of a µCT of a Li-ion pouch cell section. Figure 1

On the magnetic phase diagram of a sigma-phase Fe47Re53 compound in the H-T plane

Sigma-phase Fe47Re53 compound was investigated by means of in-field DC and AC magnetization measurements. Field cooled, MFC, and zero-field cooled, MZFC, DC magnetization curves were recorded in the magnetic field, H, up to 1000 Oe. AC magnetization measurements were performed at the constant frequency of 1465 Hz in the field up to H=500 Oe. Both types of measurements gave evidence in favor of a re-entrant character of magnetism in the studied sample. Based on characteristic temperatures determined from the measurements magnetic phase diagrams have been outlined in the H-T plane. The diagrams are similar but not identical. The main difference is that in the diagram constructed based on the DC data there is an intermediate antiferromagnetic-like phase which is absent in the AC diagram. Furthermore, the border lines (irreversibility, cross-over and Curie temperature) follow the power law but with correspondingly different exponents. The studied sample was also characterized by determining the effect of H on the degree of irreversibility and that of frustration.

Determination of Entropy Production for a Quantum System in the Presence of an Auxiliary System

A thorough understanding of entropy production, which can be used as a natural quantifier of the degree of irreversibility of a process, is both fundamentally relevant and technologically desirable. Recently, Esposito et al. (J. Phys. 12, 013013 2010), have derived an exact expression for the entropy production in terms of correlations between a system and its reservoir. However, evaluation of the mentioned correlations is virtually impossible to access in real world situations. Here, it is demonstrated that how we can overcome this problem by considering an auxiliary system and using the monogamy relations. To this aim, we consider a system A that is initially correlated with an auxiliary system B, which in turn interacts with the environment E. In the presence of the auxiliary system B, the amount of created classical and quantum correlations between the system A and the environment can be obtained by using existed monogamy properties and consequently the associated entropy production is determined. In addition, another situation is investigated in this work where only the system A is interacting with the environment E and the auxiliary system B evolves free of any direct interaction. As an example, this scenario is illustrated by considering the systems A and B as two-level systems undergoing an amplitude damping process and generalized amplitude damping process.

The Critical Size of Sn Nanograins for Achieving High Round-Trip Efficiency of Reversible Conversion Reaction in Lithiated SnO2 Nanocrystals

SnO2 has been considered one of the most promising anode materials for Li-ion batteries. However, the realization of the full capacity of SnO2 anode has been hindered mainly by the inferior reversibility of conversion (Sn+Li2O→SnO2+Li+), and especially the large initial capacity loss characterized by low initial Coulombic efficiency (ICE). In the past two decades, although many works have focused on enhancing the cycle performance of SnO2 based anodes, the achieved ICEs were still very low (<60%). Few works were devoted to understanding the fundamental reason and explore a strategy to solve this problem. Recently, we have revealed that the coarsening of Sn in the Sn/Li2O mixture, mainly induced by recrystallization, is responsible for the limited conversion of Sn/Li2O back into SnO2 during Li extraction, and achieved highly reversible conversion between Li2O and SnO2 with ICEs >86.2%, by suppressing the Sn coarsening in Li2O matrix in a sputtered SnO2 film[1]. However, it was found that the reversibility declined as the cycles increased due mainly to the gradually Sn coarsening, which was induced by the cyclic electrochemical stress (σ) imposed on the electrode[2]. Furthermore, combining nanosized transition metal with SnO2 can help to reduce the surface/interface energy of Sn nanograins and dramatically suppress the Sn coarsening, which however also affect the Coulombic efficiency and energy efficiency of the Li-SnO2 cells[3-4]. Accordingly, uncovering the critical size of Sn nanograins in lithiated SnO2 nanocrystals is of great important for enabling high round-trip efficiency of reversible conversion reaction, ensuring large stable capacity in the electrode. In this work, we report our finding that unlike the previous reports, even a pure SnO2 film consisting of nanocrystals with size around 15 nm, stable high capacity above 900mAh/g can be remained throughout 100cycles. The capacity decay in the initial dozens of cycles of SnO2 anode is mainly induced by the gradually degradation of reversible conversion reaction (Sn+Li2O←→SnO2) due to the thermal and tress driven Sn coarsening along cycles. Furthermore, as shown in Figure 1, the coarsening of Sn have reduced the reversible capacity, Coulombic efficiency, energy efficiency and Li+ ion diffusion kinetics of the SnO2 nanostructured film. The grain size of coarsening Sn (x) and the degree of irreversibility (y) monotonically increase along cycles, which is quantitatively expressed with a linear equation (y=0.0236x-0.266). It is determined that the Sn nanograins with diameters less than 11.3 nm will ensure fast interdiffusion kinetics among interfaces of Sn/Li2O for completely reversible conversion reactions, enabling full application of the high capacity of lithiated SnO2[5]. We firmly believe that these results will provide a valuable insight into designing new conversion-type electrode materials with high stable capacity for next generation rechargeable batteries. Figure 1 (a) Degree of reversibility vs. cycle number for the SnO2 film electrodes cycled among potential ranges of 0.01–3.00 and 0.01–2.00 V, respectively. (b) Average grain size and degree of irreversibility vs. cycle number. (c) Relationship between degree of irreversibility and grain size of Sn. (d) Schematic of the partially reversible conversion reaction with different grain sizes of Sn.

Global ecological, social and economic impacts of marine plastic

This research takes a holistic approach to considering the consequences of marine plastic pollution. A semi-systematic literature review of 1191 data points provides the basis to determine the global ecological, social and economic impacts. An ecosystem impact analysis demonstrates that there is global evidence of impact with medium to high frequency on all subjects, with a medium to high degree of irreversibility. A novel translation of these ecological impacts into ecosystem service impacts provides evidence that all ecosystem services are impacted to some extent by the presence of marine plastic, with a reduction in provision predicted for all except one. This reduction in ecosystem service provision is evidenced to have implications for human health and wellbeing, linked particularly to fisheries, heritage and charismatic species, and recreation.

Visibility graph analysis of temporal irreversibility in sleep electroencephalograms.

The study of sleep has continued to garner increased attention. However, most studies assume stationarity of sleep electroencephalogram (EEG) signals, whereas they are typically nonlinear and nonstationary. Little work has focused on the time irreversibility of sleep EEG signals. Hence, the aim of this work is to reveal the temporally irreversible structures of rapid-eye-movement (REM) and non-REM sleep using a visibility algorithm, which is robust to nonstationarity and finite-size effect. Results show that the temporal structure of non-REM sleep is more irreversible than that of REM sleep. The degree of irreversibility is highest in slow-wave sleep. Moreover, statistical analysis suggests that aging is the major factor that affects the irreversibility of sleep signals, while gender and body mass index contribute insignificantly. The dominant role of slow oscillations on the irreversible structures of the sleep signals is also indicated.

HOW ASSET IRREVERSIBILITY INFLUENCES THE INVESTMENT‐UNCERTAINTY RELATIONSHIP

ABSTRACTThis paper examines how uncertainty affects firms' investments for varying degrees of asset irreversibility (i.e., the wedge between purchase price and liquidation value of an asset). To identify more or less irreversible capital goods, we exploit unique survey data on German manufacturing firms over the sample period 2004 to 2012 in which managers provide information on investments' purpose (capacity expansion, replacement, restructuring, rationalization, and other). Our results indicate that only investments into the most irreversible capital goods (capacity expansion) will decrease if uncertainty rises. We also find support for other channels, such as the financial friction or the market power channel, to explain the investment‐uncertainty relationship.

Multiscale time irreversibility analysis of financial time series based on segmentation

Time irreversibility is a subject of increasing interest in an unbalanced system of various time series. Taking into account dynamic basic concepts, we provide multiscale time irreversibility analysis of financial time series based on segmentation which quantifies the time asymmetry in multiscales and is applied to several different forms of financial time series. Specifically, we adopt four distinct time irreversibility indices—Porta’s, Guzik’s and Ehler’s indices (P%, G% and E) and $$\gamma _{2,1} (k)$$ , respectively, derived from data segments on various timescales. We investigate the performance of our statistical tests for local financial time series from segmented series system with known time reversal properties and find out that it can help classify the partially representative financial markets finally. Particularly, the smaller the scale factor L is the better the ability to distinguish data. Statistical analysis shows a close relationship between G% and E. On the contrary, the connection between P% and G% or P% and E is not proven. In addition, we define a new metric $$\gamma _{2,1} (k)$$ to measure the degree of time irreversibility. By further observing the results of the proposed method for computing the degree of irreversibility of the time series, we confirm that the asymmetry is an inherent property of the financial time series, which can be extended to a wide range of scales. Finally, we apply this method to the recurrence plot and multiscale recurrence quantification analysis, to compare effectiveness of the segmentation method.

Spin-phase-space-entropy production

Quantifying the degree of irreversibility of an open system dynamics represents a problem of both fundamental and applied relevance. Even though a well-known framework exists for thermal baths, the results give diverging results in the limit of zero temperature and are also not readily extended to nonequilibrium reservoirs, such as dephasing baths. Aimed at filling this gap, in this paper we introduce a phase-space-entropy production framework for quantifying the irreversibility of spin systems undergoing Lindblad dynamics. The theory is based on the spin Husimi-Q function and its corresponding phase-space entropy, known as Wehrl entropy. Unlike the von Neumann entropy production rate, we show that in our framework, the Wehrl entropy roduction rate remains valid at any temperature and is also readily extended to arbitrary nonequilibrium baths. As an application, we discuss the irreversibility associated with the interaction of a two-level system with a single-photon pulse, a problem which cannot be treated using the conventional approach.

Relative asynchronous index: a new measure for time series irreversibility

In this paper, we suggest a new measure for testing reversibility of time series which combines two different tools: the visibility algorithm and the inversion number. First, the visibility algorithm maps the time series to the network according to a geometric criterion. After that, the degree of irreversibility of the time series can be estimated by the relative asynchronous index (RAI), based on the inverse number, between out and \(\hbox {out}^*\) degree sequences of the network (out and \(\hbox {out}^*\) represent the outgoing sequence of forward time series and reverse time series, respectively). This method does not need to rely on additional parameters, so it can avoid the error caused by parameter estimation. In addition, we also study the multiscale RAI and find that the optimal scale selection for detection time irreversibility is 1–4. Different types of time series are used to confirm the validity of this metric. Finally, we apply the method to financial time series and find that the financial crisis can be detected by RAI.

Non-Linear Effects of Uncertainty

Recent empirical studies suggest that the negative effects of uncertainty shocks are stronger in recessions than during booms. In this study, I provide a theoretical mechanism that can explain this empirical observation. I start from the argument that the effect of uncertainty on investment depends on the degree of irreversibility. I then show that the degree of irreversibility increases during recessionary times. Incorporating this fact in a DSGE model with heterogeneous firms and uncertainty shows that time-varying irreversibility is able to produce state-dependent reactions of macroeconomic aggregates to an uncertainty shock that are similar to those observed in the data.