Dissipative Behavior Research Articles

NUMERICAL ANALYSIS FOR HIDDEN CHAOTIC BEHAVIOR OF A COUPLED MEMRISTIVE DYNAMICAL SYSTEM VIA FRACTAL–FRACTIONAL OPERATOR BASED ON NEWTON POLYNOMIAL INTERPOLATION

Dynamical features of a coupled memristive chaotic system have been studied using a fractal–fractional derivative in the sense of Atangana–Baleanu. Dissipation, Poincaré section, phase portraits, and time-series behaviors are all examined. The dissipation property shows that the suggested system is dissipative as long as the parameter [Formula: see text]. Similarly, from the Poincaré section it is observed that, lowering the value of the fractal dimension, an asymmetric attractor emerges in the system. In addition, fixed point notions are used to analyze the existence and uniqueness of the solution from a fractal–fractional perspective. Numerical analysis using the Adams–Bashforth method which is based on Newton’s Polynomial Interpolation is performed. Furthermore, multiple projections of the system with different fractional orders and fractal dimensions are quantitatively demonstrated, revealing new characteristics in the proposed model. The coupled memristive system exhibits certain novel, strange attractors and behaviors that are not observable by the local operators.

Numerical investigation on the seismic performance of a RC framed building equipped with a novel Prestressed LEad Damper with Straight Shaft

This study aims at assessing the use of a novel damper, which is called the Prestressed LEad Damper with Straight Shaft (or PS-LED), for the seismic rehabilitation of RC framed buildings. This device provides high energy dissipation by the friction activated between a lead core and a shaft and achieves a high specific output force by preloading the lead during the assembly. In order to show the effectiveness of the PS-LED device for the retrofit of existing buildings, a RC structure designed according to past codes that ignored seismic actions is retrofitted with the PS-LED system considering two different damage targets: (i) in the first case, the structure is retrofitted in order to behave elastically under the design earthquake; (ii) in the second case, a partially dissipative behavior of the structure is conceived, with activation of plastic hinges, and limited and reparable damage. In order to assess the suitability of the design procedure, non-linear static analyses are performed on the upgraded building, showing a satisfactory agreement between the seismic performance and the design target. Non-linear dynamic analyses are further carried out considering a suite of bidirectional artificial ground motions with response spectra matching on average the target spectrum according to the Italian Building Code for the life-safety limit state. Finally, a comparison is performed between the performances of the building retrofitted with the PS-LED device and the building retrofitted with a conventional steel hysteretic damper (SHD), demonstrating that the PS-LED, thanks to its superior damping capacity, limits the increase in internal forces that usually affects frames equipped with SHDs, reducing the need of local strengthening of the columns and foundations and consequently the total cost of the seismic rehabilitation.

On the dissipation of ideal Hamiltonian Monte Carlo sampler

AbstractWe report on what seems to be an intriguing connection between variable integration time and partial velocity refreshment of Ideal Hamiltonian Monte Carlo samplers, both of which can be used for reducing the dissipative behaviour of the dynamics. More concretely, we show that on quadratic potentials, efficiency can be improved through these means by a factor in Wasserstein‐2 distance, compared to classical constant integration time, fully refreshed HMC. We additionally explore the benefit of randomized integrators for simulating the Hamiltonian dynamics under higher order regularity conditions.

Occurrence of pharmaceutically active compounds, parabens, and their main metabolites in soils amended with sludge and compost

The presence of pharmaceuticals and personal care products (PPCPs) in the environment has aroused considerable interest in the last few years. However, the occurrence and fate of parent compounds and their metabolites and/or transformation products in soils have been scarcely evaluated to date. In this work, the dissipation kinetics of PPCPs, which are most frequently detected in the environment, and their main metabolites, is evaluated in soil amended with digested and composted sludge. The studied compounds were monitored for 60 days after digested or compost application to the soil. Several kinetic models were used to evaluate the dissipation kinetics of the processes. Parabens and their metabolites were the compounds with the fastest dissipation rates, while the antiepileptic carbamazepine and its metabolites were the poorest degraded compounds studied. Most of the compounds showed a single first-order dissipation kinetics. The application of biphasic kinetic models can improve the knowledge about the dissipation behavior of some of them. For instance, whereas compounds such as carbamazepine showed a high persistence showing a lag phase in its dissipation, resulting in an approximately constant concentration for the first days of batch experiments, others, such as sulfamethoxazole and diclofenac, followed a dissipation kinetics in two phases: a fast dissipation attributed to the amount of compound associated to the soil-water solution and a slow dissipation that could be due to the amount of the compound adsorbed onto the soil particle. For most of the compounds, the dissipation was faster in sludge-amended soil than in soil without organic amendment. This fact could be due to the influence of microbial activity and organic matter on their dissipation.

Phase transition for piecewise linear fibonacci bimodal map

<abstract><p>In this paper we concern with the Fibonacci bimodal maps. We first study the topological properties of the Fibonacci bimodal maps in the context of kneading map and give an equivalent description of Fibonacci combinatorics. Then we construct a one-parameter family $ f_{\lambda} $ of countably piecewise linear Fibonacci bimodal maps depending on the parameter $ \lambda $ which are all odd functions. By a random walk argument on its induced Markov map, we will show that a phase transition occurs from Lebesgue conservative to Lebesgue dissipative behaviors.</p></abstract>

Stick-Slip Dynamics of Moiré Superstructures in Polycrystalline 2D Material Interfaces.

A new frictional mechanism, based on collective stick-slip motion of moiré superstructures across polycrystalline two-dimensional material interfaces, is predicted. The dissipative stick-slip behavior originates from an energetic bistability between low- and high-commensurability configurations of large-scale moiré superstructures. When the grain boundary separates between grains of small and large interfacial twist angle, the corresponding moiré periods are significantly different, resulting in forbidden grain boundary crossing of the moiré superstructures during shear induced motion. For small twist angle grains, where the moiré periods are much larger than the lattice constant, this results in multiple reflections of collective surface waves between the surrounding grain boundaries. In combination with the individual grain boundary dislocation snap-through buckling mechanism dominating at the low normal load regime, the friction exhibits nonmonotonic behavior with the normal load. While the discovered phenomenon is demonstrated for h-BN/graphene polycrystalline junctions, it is expected to be of general nature and occur in many other large-scale layered material interfaces.

An experimental investigation on the effectiveness of damping changes for damage detection in a Fibre Reinforced Plastic Plate

Fibre reinforced plastics (FRP) are extensively used because of their high specific strength and stiffness. However, throughout their service life, such materials are susceptible to damages, which when accumulated may result in catastrophic failure. Studies on effects of stiffness loss due to damage has been exercised by quite a large number of researchers but very less investigators have involved the variations in dissipative behaviour in combination with such stiffness loss. However, damage in these structures not only causes local reduction of stiffness but is also observed with increased dissipation behaviour. One of the most convenient ways to carry out health monitoring exercise to detect damages is to conduct systematic vibration testing. The present study investigates the likely changes in natural frequencies and mode shapes of a rectangular FRP composite plate along with damping factors due to the induced damage. The FRP plate considered has been modal tested and dynamic responses i.e., natural frequencies, mode shapes and modal damping factors are derived through curve-fitting technique from the frequency response function measurements. In this study, changes in dynamic responses due to a locally induced damage in the FRP plate is studied. For this, in order to maximize the effects of local reduction in the stiffness on the modal parameters, a partial-cut is provided in a localised region of the plate in the first damage case. In the second damage scenario, the partially-cut area has been filled with epoxy resin matrix to create a region with localised change in material properties and with limited stiffness loss. Damping changes has been observed to be significant and more sensitive than variations in natural frequencies and mode shapes. The study suggests that damping parameters along with stiffness changes together can be put into practice to develop an effective vibration-based health monitoring scheme

High-Performance Hydrogels via Alternate Compression–Decompression

Novel bioapplications of hydrogels draw huge attention to the development of strong and tough hydrogels that are easily obtainable with less chemical additions. Here, we demonstrate that pressure, a basic thermodynamic quantity, could enable poly(vinyl alcohol) (PVA) to effectively form a gel. The resulting hydrogels by alternate compression–decompression (ACD) have tunable superior mechanical properties compared with conventional freeze-thawed (FT) PVA hydrogels. The microstructures of the ACD hydrogels under varying parameters, including compression rate, cycles, and holding time, reveal that either a slow compression rate or cyclic compressions favor the physical cross-linking of such single polymer networks. The mechanical results display a wide range of ultimate tensile strength, tensile strain, and maximum compressive strength of ∼0.3 to 2.5 MPa, ∼200 to 550%, and ∼3 to 7 MPa, respectively. Moreover, the load resistance of such hydrogels can be further trained by low-cyclic strain hardening to a maximum compressive strength of ∼50 MPa, followed by a desirable recovery. Upon cyclic compression, the ACD hydrogels exhibit consistent energy dissipation behaviors. More importantly, the effect of modulation of pressure on the hydrogel’s mechanical properties is very likely universal for other hydrogel systems due to the basic mechanism of pressure-induced gelation for the polymers discussed.

On the influence of time-dependent behaviour of elastomeric wave energy harvesting membranes using experimental and numerical modelling techniques

The transient response of elastomeric polymers is dependent on polymer composition, temperature and the loading history. In particular, hysteresis, dissipation and creep are significant in the choice of material for elastomer membrane wave energy converters. Natural rubber is a good candidate when looking for material for a wave energy harvester since it has an excellent stretchability, is almost resistant to the environment in which the harvester will be used and has good fatigue properties. The mechanical behaviour of the natural rubber used in this work has been deeply characterised: the material resulted to have a very little hysteretical behaviour (that is a very low energy dissipation during stretching) but also to show a strain-dependency, stress softening, and relaxation at constant stretch. Low dissipation represents the best case scenario for energy harvesting; in reality reinforcement of the material is required which adds to the dissipative behaviour. Afterwards, an extended finite strain viscoelastic constitutive model is proposed that is calibrated analytically to the experimental data to identify the relevant material parameters resulting in non-linear viscosity functions in the evolution equations of the constitutive model. The model was able to capture the minimal dissipation behaviour with good degrees of accuracy. Results are shown for a flexible membrane wave energy converter under creep and cyclic loading. A parametric study is made comparing the experimentally characterised polymer with different amounts of viscous dissipation. The response of the wave energy converter shows that even minimal amounts of dissipation manifests itself into changes in the pressure–volume function and reduction in energy capture through hysteresis. The new material model shows, for the first time, that the control of internal pressure in wave energy membranes must take into account transient material effects.

Energy dissipation mechanism of fiber metal laminate under low-velocity impact

Identification of the energy dissipation behavior of fiber metal laminate under low-velocity impact is necessary for understanding its impact response and damage mechanism, as the impact scenario is typical for energy conversion. In this paper, the glass fiber reinforced aluminum laminate (Glare) was tested under different impact energy to achieve typical low-velocity impact responses and damage patterns. By which the finite element model was built and verified to be effective, by employing the Johnson–Cook model for aluminum, Hashin’s criteria and exponential damage evolution law based VUMAT subroutine for GFRP, and bi-linear traction–separation cohesive zone model for their interface. Based on the history energy outputs on internal energy, elastic strain energy, plastic deformation dissipated energy, and damage dissipated energy in the finite element model. The contributions of the constituents in the energy absorption aspect of Glare were firstly revealed. Furthermore, how the energy was dissipated by the laminate and by the constituents, i.e., the distributions of energy evolutions in laminate and constituent levels, were clarified. Finally, damage evolutions of individual layers and the failure sequence of the entire laminate were elaborated. The results achieved have specified the energy dissipation mechanism and its association with the impact response of Glare.

Dissipation, Residue Behavior and Dietary Risk Assessment of Difenoconazole on Jujube (Ziziphus jujuba Mill.)

Difenoconazole is a triazole germicide that is usually applied to prevent fungal diseases on crops with high efficiency and safety. Jujube is a spiny Rhamnaceous plant that originated in China more than 4000 years ago and is extensively cultivated in northern China nowadays. To evaluate the safety of difenoconazole in jujube, supervised field trials were carried out in six provinces of China, and the final residue and dissipation behavior of difenoconazole on jujube were determined by gas chromatography (GC). The results showed that when addition levels were 0.02, 0.2, and 2 mg·kg−1, average recoveries of the aforementioned method for difenoconazole in jujube can be put into the range of 73–108%, and relative standard deviation (RSD) was 3–9%. The limit of quantitation (LOQ) for this method was 0.02 mg·kg−1. In the final residue test, difenoconazole was sprayed to deal with the jujube at 100 and 150 mg·kg−1 doses twice or three times, respectively, while the dissipation test was applied only once at a 150 mg·kg−1 dose. Final residue testing results have revealed that when jujube samples were harvested and tested at 7, 14, and 21 days post-application, difenoconazole residues in samples were 0.11–1.59, 0.05–0.77, 0.04–0.63 mg·kg−1, respectively. The dissipation testing results showed that the digestion process of difenoconazole in jujube tends to be a gradual reduction process and the dynamic regularity of the residue dissipation proves consistent with the first-order dynamics reaction equation. The half-life (t1/2) for difenoconazole residue dissipation in Qingdao and Yuncheng was 13.1 days and 16.5 days, respectively. The risk quotient (RQ) was 84.9% lower than 100%, showing that dietary intake risk to difenoconazole was acceptable and the maximum residue limit (MRL) of difenoconazole on jujube is recommended to be 2 mg·kg−1.

Comprehensive evaluation of novel fungicide benzovindiflupyr at the enantiomeric level: Bioactivity, toxicity, mechanism, and dissipation behavior

Racemates in the environment can lead to inaccurate risk assessment. To obtain the enantiomeric level information of benzovindiflupyr for accurate risk assessment, the absolute configuration of benzovindiflupyr was first confirmed, and the enantioseparation method was developed by supercritical fluid chromatography tandem mass spectrometry. The enantioselectivity for bioactivity and toxicity was investigated, and the mechanism was explored by molecular docking and detecting succinate dehydrogenase (SDH) activity and content of succinate acid. 1S,4R-(−)-benzovindiflupyr was identified as the most active against the six targeted phytopathogens, which showed higher 1.7–54.5 times than 1R,4S-(+)-benzovindiflupyr. Additionally, 1S,4R-(−)-benzovindiflupyr (LD50: 21.54 μg L−1) was 103.7 times more toxic than 1R,4S-(+)-benzovindiflupyr against Daphnia magna. 1S,4R-(−)-benzovindiflupyr had a stronger affinity for SDH and significantly inhibited SDH activity, resulting in an increase in succinate acid in the tricarboxylic acid cycle, while its downstream products, fumaric and L-malic acid were significantly reduced. Moreover, the dissipation behavior of benzovindiflupyr on three vegetables was evaluated. 1S,4R-(−)-benzovindiflupyr was preferentially degraded in tomato, but opposite in leaves. The enantioselectivity in pepper and cucumber leaves was the same as in tomato, while there was no enantioselectivity in pepper and cucumber. The study provides a basis for accurate risk assessment and the development of high-effective and low-risk fungicides.

Performance of chocolate bar-shaped modular thermal management system combined metal lattice liquid-cooling plate with paraffin in high-rate discharge

A chocolate bar-shaped hybrid battery thermal management system combined with a metal lattice liquid-cooling plate with paraffin has been proposed to improve the severe temperature rise and inhomogeneity of the prismatic lithium-ion battery at a high discharge rate. The cooling capabilities of different liquid-cooling tube arrangements of a prismatic battery have been compared, and the impacts of coolant flow rate, the metal lattice porosity and the liquid-cooling tube wall thickness on the cell's heat dissipation behaviour in various systems have been investigated. Multi-objective optimization has been conducted to obtain the optimal structural parameters of the system. The results indicate that the parallel arrangement of liquid-cooling tubes can ensure an excellent cooling capacity and a low system mass. The metal lattice plate with phase change material has a most outstanding cooling performance and highest mass group efficiency than other hybrid cooling systems. The highest temperature, temperature difference and the system's group efficiency will decline with the metal lattice's porosity decrease. The cooling capability of the system will be affected by the increased wall thickness of the LCT due to the balanced effect of the flow rate increase and thermal resistance. Under the optimal parameter combination, the module's highest temperature, temperature difference and group efficiency are about 44.95 °C, 4.35 °C and 78.98 % in 3C high-rate discharge, respectively.

Experimental Investigation on the Cyclic In-Plane Behavior of GFRP-Reinforced Concrete Shear Walls

The current study presents an experimental investigation performed on slender reinforced concrete shear walls, representing a common lateral-load resisting system of mid-rise buildings. The walls were reinforced with steel and glass fiber-reinforced polymer (GFRP) bars and tested up to failure under reversed quasi-static cyclic loading to investigate the capability of GFRP bars in reinforcing RC shear walls under seismic loads. Moreover, the effect of the GFRP reinforcement ratio on the structural response, deformation performance, and failure mode resulting in RC walls, compared with its behavior when reinforced with steel bars, is also investigated. Six full-scale shear walls with an aspect ratio of 3.25 were constructed. The reference wall was entirely reinforced with steel bars. Two specimens were reinforced by hybrid scheme of GFRP–steel bars. The remaining three shear walls were entirely reinforced with GFRP bars. The overall performance of each wall was characterized by investigating the lateral load capacity, hysteretic response, cracks propagation, ductility, and the behavior of energy dissipation. The experimental results showed that GFRP-reinforced concrete walls had an elastic behavior characterized by a stable hysteretic response with recoverable deformation of more than 80% of the ultimate load. However, sudden and brittle failure was attained for the wall with a high GFRP reinforcement ratio. GFRP decreases the displacement ductility of the shear walls by an average of 32.9%, depending on the reinforcement ratio, compared to that reinforced by steel bars. Moreover, lower energy dissipation through inelastic deformation was obtained for the walls reinforced with GFRP bars. Nonetheless, when GFRP bars are combined with steel bars, acceptable levels of dissipated energy are attained compared to the steel-reinforced wall.

Energy dissipation in multistable auxetic mechanical metamaterials

Multistable mechanical metamaterials are periodic structures whose unit cells show bistable configurations. The snap-through behavior of the unit cell enhances the energy dissipation of the metamaterials. The materials are reusable and can dissipate energy multiple times since the deformation is within the elastic region. This paper presents two types of two-dimensional auxetic metamaterials: the shuriken-shaped motif with four axes of symmetry and the triangle motif with six axes of symmetry. The cylindrical and three-dimensional (3D) configurations are designed with the geometric topology method. We carry out experiments with 3D printed samples, finite element analysis (FEA), and theoretical investigation to reveal the various mechanisms of energy dissipation. The results demonstrate that the planar metamaterials exhibit different energy dissipation along various loading directions. Each type of metamaterial exhibits discrepant force-displacement characteristics. The triangle motif performs better than the shuriken-shaped motif in terms of energy dissipation along some loading directions. The proposed auxetic metamaterials perform better than the conventional multistable structures with zero Poisson’s ratio. Energy dissipation and auxetic behavior of the typically cylindrical and 3D metamaterials are verified numerically and experimentally.

Quasi‑static Cyclic In‑plane Testing of Slender GFRP-Reinforced Concrete Shear Walls

Using Glass fiber-reinforced polymer (GFRP) bars as a replacement for conventional steel bars is one of the most potential solutions to steel-corrosion-related problems in concrete. Their durability and high strength-to-weight ratio make them a cost-effective and applicable alternative to conventional steel bars. This study investigates the characteristic behavior of concrete shear walls reinforced with steel, GFRP, and a hybrid scheme of steel and GFRP bars under seismic loading. Six full-scale RC shear walls with an aspect ratio of 3.25 were tested under pseudo-static reversed-cyclic lateral load to investigate the potential of a hybrid reinforcement scheme of steel-GFRP to improve the seismic behavior of slender RC shear walls. The overall performance of each tested wall was characterized by investigating the hysteretic response, crack propagation, lateral load capacity, and energy dissipation behavior.

The energy release rate of crack growth in an irradiation-induced thermo-diffusion-mechanical (I-TDM) coupling system

The material cracking behavior in the reactor is generated under the irradiation effect accompanied by thermal expansion, fission product diffusion, and mechanical load. In this study, the energy release rate for crack growth under irradiation has been deduced synthetically according to the thermodynamically consistent method and numerically implemented by the finite element method (FEM). Variation in the total energy was obtained based on the principle of minimum potential energy in which the dissipative behavior can be characterized by fission energy, irreversible heat flow, and diffusion of fission products. Through calculating the variation in the total energy with respect to crack length, the energy release rate for crack propagation was analytically represented. Additionally, the total energy release rate for deflective cracks was also derived to predict the crack kinking. Furthermore, the numerical implementation of the presented model was performed by FEM and the equivalent domain integral method. Effects of irradiation on the physical fields and the energy release rate near the crack tip were investigated and analyzed in such a complex I-TDM coupling system. This study can be developed to investigate fracture problems, assess structural integrity, and evaluate material strength of irradiated materials.

Assessment of a novel hysteretic friction damper for the seismic retrofit of reinforced concrete frame structures

In this paper, a novel hysteretic friction damper, called Prestressed LEad Damper with Straight Shaft (or PS-LED), is presented as a viable solution for the seismic rehabilitation of existing RC framed buildings. The PS-LED is characterized by high stiffness and damping capability combined with a compact design, and low manufacturing cost, which make it suitable for social housing. The constitutive behavior of the PS-LED, assessed experimentally in cyclic tests at different speeds, is formulated in the OpenSees framework through a simple rheological model comprising a parallel of a non-linear spring and a viscous model.To explore the viability of the PS-LED for seismic upgrade of existing buildings, a numerical investigation is performed by considering a RC frame structure, paradigmatic of a category of Italian buildings designed according to outdated codes. The case-study structure retrofit is designed considering two possible damage targets: (i) in the first case, the upgrade is performed in order to achieve elastic response of the structure under the basic design earthquake; (ii) in the second case, a partially dissipative behavior of the RC frame is conceived, with activation of plastic hinges to a repairable level. Non-linear static and Non-linear dynamic analyses are performed, showing a satisfactory agreement between the seismic performance and the design targets.As final stage, a comparison between two retrofit solutions with either the PS-LED or with a conventional steel hysteretic damper (SHD) is performed, demonstrating that the PS-LED, thanks to its high damping capacity, is able to control the increase in internal forces that usually affects frames upgraded with SHDs.

Energy Dissipation and Electrical Breakdown in Multilayer PtSe2 Electronics.

Investigating the energy dissipation in micro- and nanoscale is fundamental to improve the performance and reliability of two-dimensional (2D) electronics. Recently, 2D platinum selenide (PtSe2) has drawn extensive attention in developing next-generation functional devices due to its distinctive fusion of versatile properties. Toward practical applications of PtSe2 devices, it is essential to understand the interfacial thermal properties between PtSe2 and its substrate. Among them, the thermal boundary conductance (TBC) has played a critical role for out-of-plane heat dissipation of PtSe2 devices. Here, we identify the energy dissipation behavior of multilayer PtSe2 devices and extract the actual TBC value of the PtSe2/SiO2 interface by Raman thermometry with electrical bias. The obtained TBC value is about 8.6 MW m-2 K-1, and it belongs to the low end of as-known solid-solid interfaces, suggesting possible applications regarding thermoelectric devices or others reliant on a large temperature gradient. Furthermore, the maximum current density of the PtSe2 device determines its threshold power, which is crucial for improving device design and guiding future applications. Therefore, we explore the electrical breakdown profile of the multilayer PtSe2 device, revealing the breakdown current density of 17.7 MA cm-2 and threshold power density of 0.2 MW cm-2, which are larger than typical values for commonly used aluminum and copper. These results provide key insights into the energy dissipation of PtSe2 devices and make PtSe2 an excellent candidate for thermal confinement applications and nanometer-thin interconnects, which will benefit the development of energy-efficient functional 2D devices.

Heat Dissipation Behavior of a Low-Strength-Steel Welded Joint in Ultrasonic Fatigue

The coupled effects of heat and frequency in very-high-cycle fatigue are known under ultrasonic testing, while the heat dissipation behavior of welded joints is less investigated. In this work, the specimen surface temperature of a low-strength-steel welded joint and its base metal were monitored by infrared thermal imaging technique under ultrasonic fatigue loading. Results showed that the surface temperature distribution of both welded and base metal exhibited a parabola shape, and the temperature evolved with three stages. The location of the highest temperature within the weld metal correlated well with fatigue failure location. The inhomogeneity and asymmetry of temperature distribution implied a dominant role for heat transfer mode and insignificant influence of microstructure heterogeneity or specimen type. The nature of heat dissipation in low-strength steel in ultrasonic fatigue was thermal–mechanical coupling effect, which should be paid close attention in the standardization of ultrasonic fatigue testing.