Material Pairs Research Articles

Differentiation Between Abscesses and Unnecessary Intervention Fluid After Pancreas Surgery Using Dual-Energy Computed Tomography.

This study aimed to evaluate the potential of dual-energy computed tomography (CT) to distinguish postoperative ascites, pancreatic fistula, and abscesses. Patients who underwent biliary and pancreatic surgery performed at our institution between June 2021 and February 2022 were included in the study. Postoperative body fluid samples were collected through a drain or percutaneous drainage. These samples were set in a phantom, and imaging data were obtained using dual-energy CT. Image analysis was performed to obtain CT values at each energy in virtual monoenergetic images (VMIs), effective atomic number, iodine map, and virtual non-contrast (VNC) images. VMIs were calculated from 80 and 140 kVp tube data at 10 kV each from 40-140 kV. Additionally, the effective atomic number, iodine map, and VNC images were reconstructed from the material decomposition process using water and iodine as the base material pair. In this study, 25 patients (eight with abscess and 17 with ascites) were included. No significant association was observed between the presence or absence of abscess and malignancy or surgical procedure. The intervention was performed in six of the eight patients with abscesses. In contrast, five of the 17 patients with postoperative ascites required intervention. A significant relationship was observed between the intervention and the presence of an abscess. Significant differences in C-reactive protein values and the incidence of fever were observed between the groups. Only VNC showed a significant difference between the groups. VNC using dual-energy CT could differentiate abscesses from postoperative fluid.

Study of The Microstructure and Mechanical Property Relationships of Gas Metal Arc Welded Dissimilar Protection 600T, DP450 and S275JR Steel Joints

The need for combining dissimilar materials is steadily increasing in the manufacturing industry, and the resulting products are expected to always have high performance. While there are various methods available for joining such material pairs, one of the commonly preferred techniques is fusion welding. In this study, three different steel materials (Protection 600T, DP450, and S275JR) were joined using gas metal arc welding (GMAW) in different combinations (similar/dissimilar). The microstructure and mechanical properties of the joints were evaluated. Tensile test, Vickers microhardness (HV 0.1), bending, Charpy V-notch impact testing, and microstructure examinations were conducted to analyze the weld and heat-affected zone. The tensile strengths of the base metal materials Protection 600T, DP450, and S275JR were found to be 1524.73 ± 18.7, 500.8 ± 10.4, and 508.5 ± 9.5 MPa, respectively. In welded samples of similar materials, the highest efficiency was found to be 103.05% for DP450/DP450, while in dissimilar welded joints, it was 105.5% for the DP450/S275JR pair. Hardness values for the base materials Protection 600T, DP450, and S275JR were measured as 526.5 ± 10.5, 153.8 ± 1.8, and 162.5 ± 5.2, respectively. In all welded samples, there was an increase in hardness in the weld zone (due to the welding wire) and the heat-affected zone (due to grain size refinement). While the impact energy values of similar material pairs were close to the base material impact energy values, the impact energy values of dissimilar material pairs varied according to the base materials. In addition, in joints made with similar materials, the bending force was close to the base materials, while a decrease in bending force was observed in joints formed with dissimilar materials. As a result, the welding of DP450 and S275JR materials was carried out efficiently. Protection 600T was welded with other materials, but its welding strength was limited to the strength of the material with low mechanical properties.

Thermal Insulation of “akassa” Hot Preservation Baskets Using Cow Dung Coatings

The use of eco-materials for thermal insulation is becoming more and more recommended compared with synthetic materials. They have the advantage of being biodegradable and sometimes less expensive. To this end, the use of packaging with the function of hot preservatives but made from local and biodegradable materials is a very interesting alternative to synthetic enclosures. This work involved formulating eco-materials made from cow dung coatings and a mixture of cow dung coatings with a framework of fibres extracted from the stalks of oil palm leaves. In addition, to monitor the temperature rise in the various eco-materials manufactured and characterise them using the hot ribbon method to determine their effusivity and thermal conductivity. The pair of materials exposed to heating showed a gradual rise in temperature within the materials when the resistor was energised. A slightly faster rise was observed in the first fifty minutes. The results obtained indicate that the cow dung has a higher effusivity (E = 517.32 J.m<sup>-2</sup>. °C<sup>-1</sup>. s<sup>-1/2</sup>) than its composite (E = 501.20 J.m<sup>-2</sup>. °C<sup>-1</sup>. s<sup>-1/2</sup>). The thermal conductivity values obtained indicate that the cow dung has a higher thermal conductivity (λ'=0.19 W.m^(-1).K^(-1)) than that of the composite structure (λ=0.15 W.m^(-1).K^(-1)). From the above, the presence of the fibre frame has the effect of reducing thermal conductivity because it absorbs more energy. The materials produced therefore have proven insulating properties, which are improved when the framework is made from fibres extracted from the stalks of oil palm leaves. Using oil palm fibres in combination with cow dung as eco-materials for thermal insulation is an excellent alternative to synthetic insulation.

Multi-objective optimisation of a thermocline thermal energy storage integrated in a concentrated solar power plant

Most of CSP plants built today are all equipped with storage devices. Most are sensitive heat storages, in particular 2-tank systems. The aim of this study is to optimise a thermocline storage, designed for the Andasol CSP plant in Spain, on the basis of exergy, environmental and economic criteria. The optimum tank geometry, particle size and heat transfer fluid/filler material pair must be determined. To achieve this, six different fillers operating with Dowtherm A synthetic oil are being investigated: machined ceramics, ceramics obtained from waste materials and natural rock. The NSGA-II multi-objective genetic algorithm is used to solve the problem. This optimisation selects recycled ceramics as best filler materials. The exergy efficiency is not affected by the filler, with more than 99.8%. The application of TOPSIS method combined with weighting derived from Shannon entropy, selects recycled ceramic obtained from electric furnaces as the best filler. This tank has a tapered shape (diameter of 27.4 m, height of 22.2 m) and a very small particle diameter (6 mm). Compared with an earlier design available in literature, the environmental impact is reduced by 19%. The LCOE reaches 10.8 c€/kWhe, a 48% reduction compared with the selling price of heat in Spain (in 2021).

Numerical simulations of temperature loads on multilayer Laue lenses

We present numerical simulations of the heat loads on novel diffractive X-ray optics, known as multilayer Laue lenses, exposed to high-intensity X-ray beams produced by an X-ray free electron laser (XFEL). These lenses can be used to focus XFEL beams to nanometer spots. The temperature distribution within the lens and temperature evolution as a function of incident pulse frequencies were calculated for two different lens geometries and several material pairs and material ratios of the MLLs. Simulations considered the special pulse structure of European XFEL with X-rays being delivered in pulse trains. After defining the geometric model, computational grid, material properties, and boundary conditions, a grid sensitivity study was carried out. We solved the transient heat energy transport equation in solids for mixed boundary conditions. The results of these simulations will help select materials and lens geometry for future XFEL experiments.

Experimental development and validation of tribological run-in strategies to reduce friction in hydraulic applications

A particularly demanding contact in axial piston pumps is the one between cylinder block and valve plate. The tribological behavior of the contact can be changed by a run-in process. Publications on fast and efficient run-in are rare as this knowledge is often considered confidential. For this paper, tests have been carried out on a disc-on-disc tribometer to examine the run-in behavior of a material pairing and to identify suitable parameters for run-in. A methodology has been developed which can be used to find the optimal normal load and rotational speed for the run-in process to shorten the run-in time significantly.

Vertebral and Femoral Bone Mineral Density (BMD) Assessment with Dual-Energy CT versus DXA Scan in Postmenopausal Females.

This study aimed to demonstrate the potential role of dual-energy CT in assessing bone mineral density (BMD) using hydroxyapatite-fat material pairing in postmenopausal women. A retrospective study was conducted on 51 postmenopausal female patients who underwent DXA and DECT examinations for other clinical reasons. DECT images were acquired with spectral imaging using a 256-slice system. These images were processed and visualized using a HAP-fat material pair. Statistical analysis was performed using the Bland-Altman method to assess the agreement between DXA and DECT HAP-fat measurements. Mean BMD, vertebral, and femoral T-scores were obtained. For vertebral analysis, the Bland-Altman plot showed an inverse correlation (R2: -0.042; RMSE: 0.690) between T-scores and DECT HAP-fat values for measurements from L1 to L4, while a good linear correlation (R2: 0.341; RMSE: 0.589) was found for measurements at the femoral neck. In conclusion, we demonstrate the enhanced importance of BMD calculation through DECT, finding a statistically significant correlation only at the femoral neck where BMD results do not seem to be influenced by the overlap of the measurements on cortical and trabecular bone. This outcome could be beneficial in the future by reducing radiation exposure for patients already undergoing follow-up for chronic conditions.

Long-Term Investigations of Different Bearing Configurations at Solid-Lubricated Rolling Bearings

This paper presents the results of wear and service life investigations of solid-lubricated rolling bearings. The cage of the bearing consists of a PI matrix with 15% MoS2 and serves as a lubrication depot in addition to silver coated balls. First, investigations of the bearing system within the bearing service life are presented, and the torque curve, the wear mass and surface analyses are discussed. With regard to wear, it is shown which that the bearing rings tend to increase in mass over the life of the bearing and while the balls and the cage tend to decrease in mass. With respect to the elemental surface condition, the surfaces of the bearing rings and balls are examined with respect to the mass of the elements on them. Furthermore, service life investigations with different material pairings are presented, whereby the focus here is on the service life achieved, in addition to the torque curve, the wear development and the surface analysis. It could be shown, that MoS2 in the cage results in a longer service life while an Ag coating of the balls has no positive effect on the service life and even seems so reduce it when combined with MoS2.

The role of embedded coordinates for disclinations and disconnection components

The standard model is applied for partial disclination pairs in hard materials. These defects comprise two partial disclinations and an intervening fault that can be a twin boundary, grain boundary or interphase boundary. In three dimensions there are six types. Two of them can be considered Somigliana disclinations. The standard model includes geometrically nonlinear embedded coordinates. It entails partitioning of displacements that result in configurations and strain fields not considered classically for partial disclinations. These concepts are applied to boundary junctions, disconnections, and multiple twins. Recovered stress-free structures are considered.

Wheel-rail contact wear analysis on curved lubricated track for heavy haul locomotive studies

The effect of lubrications on a curved track to heavy-haul wheel-rail contact wear is studied. To analyse wheel-rail contact wear damage due to existing high-adhesive AC locomotive, a methodology for investigation is proposed, and the locomotive models are required to run at 20 km/h under maximum traction efforts, and the simulations include a DC locomotive for comparison. An extended creep force model, which was developed by Polach and has been widely used for the wheel-rail contacts under dry and wet conditions with variable friction coefficients, is further extended to apply for the typical low-coefficient-friction modifier, oil, and grease lubricant conditions. The wear models from two pairs of wheel-rail materials are used to predict the wear rates, and the wear numbers Tγ are presented for discussions. The simulations show that the lubricants significantly reduce the wheel-rail contact wear.

Design of a monocapillary with an inner Al2O3/HfO2 multilayer to obtain focused monochromatic hard X-rays

An X-ray monocapillary with an inner multilayer can be a promising optical device to obtain focused monochromatic X-rays. A focused beam is acquired via controlling the shape of the monocapillary meanwhile monochromatic X-rays are screened out by the inside multilayer. For hard X-rays such as Cu-kα line 8.04 keV and Mo-kα line 17.44 keV, Al2O3/HfO2 is an effective material pair for the X-ray multilayer that can reflect the X-rays at an acceptable efficiency. In this work, four tapered-monocapillaries with inner Al2O3/HfO2 multilayers are designed to focus and monochromatize X-rays (8.04 keV and17.44 keV, respectively) from the point source and collimated beam. The theoretical transmission performance, including the beam size, reflectivity, and monochromaticity of the device, is also calculated. The results show that the ideal optics can focus desired X-rays with efficiency of about 60%. It provides a reference for fabricating this optics in the future, especially via the atomic layer deposition (ALD) technique, which represents great potential to coat uniform film on a curved surface.

Construction and parameter calibration of potato double‐layer flexible bonding model based on discrete‐element method

AbstractThe current discrete‐element simulation models for potatoes are multisphere polymer models derived from the Hertz–Mindlin (no slip) contact model in the discrete‐element simulation software (EDEM). These models oversimplify by considering potato peel and flesh as sharing identical mechanical properties within the structure. This oversimplification impedes a thorough investigation of the characteristics and mechanisms underlying potato peel‐breaking damage during mechanized harvesting, making in‐depth exploration challenging through simulation experiments. Consequently, this study conducted laboratory tests to determine the water content of potato peel and flesh, as well as the friction coefficients and collision recovery coefficients for various material pairs: flesh–steel, peel–steel, peel–peel, peel–flesh, and flesh–flesh. Subsequently, based on these findings, a double‐layer flexible bonding model for potato samples and whole stems under specific water content conditions was developed using EDEM software. The bonding parameters of the double‐layer flexible model for potato samples were refined through virtual shear calibration tests, leading to the identification of the optimal parameter combination: Flesh particle–flesh particle normal stiffness(tangential stiffness) per unit area X1 = 4.39 × 108 N/m3, peel particle–flesh particle normal stiffness(shear stiffness) per unit area X3 = 1.81 × 109 N/m3, peel particle–peel particle shear stiffness per unit area X6 = 1.99 × 109 N/m3, peel particle–peel particle critical normal stress X7 = 2.06 × 109 Pa. To validate the accuracy of the bonding parameters, shear and compression validation tests were conducted on entire potato stems. Comparison of the validation results from laboratory tests and simulation tests revealed an average relative error of e = 3.25%, signifying the feasibility of the constructed double‐layer flexible bond model for potatoes. This model meets the requirements for studying the characteristics and mechanisms of peel‐breaking damage in potatoes.Practical ApplicationsThe paper introduces a novel double‐layer flexible bonding model for potatoes using the discrete‐element method (DEM), which accurately simulates the mechanical properties and damage characteristics of potato peels and flesh. This research has significant practical applications in agricultural machinery design, improving the efficiency and reducing the damage during mechanical harvesting. By providing a more realistic simulation of potato behavior under mechanical stress, it can guide the development of gentler handling equipment, reduce waste, and enhance the quality of harvested potatoes. This contributes to optimizing the post‐harvest process, ensuring better storage, and extending the marketable life of potatoes.

CoCrFeMnNi0.8V/Cr3C2-Ni20Cr High-Entropy Alloy Composite Thermal Spray Coating: Comparison with Monolithic CoCrFeMnNi0.8V and Cr3C2-Ni20Cr Coatings

High-entropy alloys (HEAs) are revolutionizing the field of surface engineering, challenging traditional alloy frameworks with their superior mechanical attributes and resistance to corrosion. This investigation delves into the properties of the CoCrFeMnNi0.8V HEAs, both as a standalone material and when blended with Cr3C2-Ni20Cr, to evaluate their efficacy as cutting-edge surface treatments. The addition of vanadium to the CoCrFeMnNi0.8V alloy results in a distinctive microstructure that improves hardness and resistance to abrasion. The incorporation of Cr3C2-Ni20Cr particles enhances the alloy’s toughness and longevity. Employing high-velocity oxy-fuel (HVOF) thermal spray methods, these coatings are deposited onto steel substrates and undergo detailed evaluations of their microstructural characteristics, abrasion, and corrosion resistance. Findings reveal the CoCrFeMnNi0.8V coating’s exceptional ability to withstand corrosion, especially in environments rich in chlorides. The hybrid coating benefits from the combination of the HEA’s inherent corrosion resistance and the enhanced wear and corrosion resistance provided by Cr3C2-Ni20Cr, delivering comprehensive performance for high-stress applications. Through the fine-tuning of the application process, the Cr3C2-Ni20Cr reinforced high-entropy alloy coating emerges as a significant advancement in protective surface technology, particularly for use in marine and corrosive settings. This study not only highlights the adaptability of HEAs in surface engineering but also prompts further investigation into innovative material pairings.

Hydration Programmable, Shape Memorable Artificial Muscles for Antagonistic Movements

AbstractShape memory polymers (SMPs) capable of generating various deformations from anisotropic temporary shapes to permanent shapes have been emerging as soft robots. However, traditional SMPs cannot imitate the antagonistic movement of human skeletal muscles due to their modulus limitations in shape programming and recovery process. Herein, hydration programmable shape memory polymer (HP‐SMP)‐based fibers that can undergo reversible actuation by assembling antagonistic pairs are reported, where the shape programming of the antagonist muscle relies on the contraction of agonist muscle. HP‐SMP fibers are composed of tunicate cellulose nanocrystals (TCNCs) reinforced semi‐interpenetrating polymer networks. Leveraging their distinctive structure and hydration programmability, the HP‐SMP fibers exhibit large actuation strain (−60%) and high work capacity (751 J kg−1), allowing for reversible actuation under constant stress. Most significantly, the continuous antagonistic movements of HP‐SMP fibers assembled into artificial limbs are demonstrated to realize humanoid motion. This work provides new possibilities for replicating a series of lifelike human movements through the biomimetic design of antagonistic pairs of artificial muscles, utilizing renewable and sustainable biosourced materials.

New Avenues for Organic Solar Cells Using Intrinsically Charge-Generating Materials.

The molecular electron acceptor material Y6 has been a key part of the most recent surge in organic solar cell sunlight-to-electricity power conversion efficiency, which is now approaching 20%. Numerous studies have sought to understand the fundamental photophysical reasons for the exceptional performance of Y6 and its growing family of structural derivatives. Though significant uncertainty about several details remains, many have concluded that initially photogenerated excited states rapidly convert into electron-hole charge pairs in the neat material. These charge pairs are characterized by location of the electron and hole on different Y6 molecules, in contrast to the Frenkel excitons that dominate the behavior of most organic semiconductor materials. Here, we summarize the current state of knowledge regarding Y6 photophysics and the key observations that have led to it. We then link this understanding to other advances, such as the role of quadrupolar fields in donor-acceptor blends, and the importance of molecular interactions and organization in providing the structural basis for Y6's properties. Finally, we turn our attention to ways of making use of the new photophysics of Y6, and suggest molecular doping, crystal structure tuning, and electric field engineering as promising avenues for future exploration.

Dimensional Fidelity and Orientation Effects of PolyJet Technology in 3D Printing of Negative Features for Microfluidic Applications.

Negative features in microdevices find a wide range of applications. The process of 3D printing has revolutionized their fabrication due to the combination of good resolution and integration capability. Herein, we report on a systematic study of the effects of materials and print directions on the 3D printing of microfluidic channels as negative features under PolyJet technology. Specifically, the Statasys Objet500 printer was used for this study. We printed two sets of chips (n=10 each), each of which contains channel pairs of a high-contrast reference material and a sacrificial material, respectively. Both materials were embedded in a clear photopolymer resin. The channel pairs ranged in planned width from 64 to 992 μm. To explore the effect on print orientation, channels were printed either parallel or perpendicular with respect to the jetting head's movement. The width of each channel of a pair was compared for each planned width and each combination of materials. The effect of print orientation on channel morphology was also investigated. We found that reproducibility and accuracy were highest at a planned channel width of approximately ≥600 μm and that channel morphology was most suitable when the jetting head of the printer moved parallel to the channel's longitudinal axis. The results should be of interest to any users who wish to create negative features using PolyJet 3D technology.

Investigating enhanced interfacial adhesion in multi-material filament 3D printing: a comparative study of t and Mickey Mouse geometries

In this study, a novel design to enhance interfacial adhesion in multi-material components produced through filament 3D printing techniques is presented. Multi-material additive manufacturing often faces challenges related to poor chemical affinity between polymers and physical discontinuities between component sub-parts. To address these issues, an interface geometry that leverages both diffusion and mechanical adhesion mechanisms to facilitate interlocking is proposed. The performance of the widely used T-shaped geometry, as per existing literature, with a newly introduced Mickey Mouse lobate modified shape is compared. Additionally, the linear butt interface, which relies solely on chemical diffusion is investigated. For the study, Polylactic Acid and Polyethylene Terephthalate as the material pairs was selected. The findings underscore the significant impact of interface geometry on the mechanical properties of multi-material components. Using the ultimate tensile strength of the standard ISO 527-2 specimen as a reference, a butt interface results in a residual strength of 60% for homogeneous materials, but only 10% for heterogeneous materials. The adverse impact of the heterogeneous materials configuration was alleviated by the interfaces, leading to an enhancement of 7% and 58% for the Mickey Mouse and T geometries, respectively. While the Mickey Mouse geometry effectively reduces stress concentrations, it falls short of achieving the desired improvement in multi-material adhesion between parts. This outcome suggests the necessity of further research, particularly towards optimizing the proposed geometry for enhanced performance.

Overprinting of TPU onto PA6 Substrates: The Influences of the Interfacial Area, Surface Roughness and Processing Parameters on the Adhesion between Components.

The hybridisation of injection moulding (IM) and additive manufacturing (AM) offers the opportunity to combine the high productivity of IM and the high flexibility of AM into a single process. IM parts can be overprinted through fused filament fabrication (FFF) to allow for the customisation of parts or to add new functionalities. However, the right material pair must be chosen, and processing parameters must be optimised to achieve suitable adhesion between the components. The present study dealt with the investigation of the influence of the interfacial area, substrate surface roughness and overprinting processing parameters on the adhesion between the polyamide 6 (PA6) substrate and thermoplastic polyurethane (TPU) rib overprinted via FFF. PA6 substrates were produced through the IM of plates into a mould with different textures to obtain substrates with three different surface roughnesses. The ribs with varied interfacial areas were overprinted onto produced substrates using a desktop FFF 3D printer. To study the effect of overprinting processing parameters, the ribs were overprinted under varying printing and substrate temperatures and printing speeds according to the Box-Behnken design of experiments (DoE). The chemical composition and thermal properties of used materials were determined via attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA). The surface properties of prepared substrates were studied via digital optical microscopy (OM), through surface roughness measurements using a confocal microscope, through contact angle (CA) measurements and through the determination of free surface energy (SFE). The adhesion between the components was determined by evaluating the tear-off strength using a universal testing machine (UTM). With an increasing interfacial area, the tear-off strength decreased, while substrate surface roughness had no statistically significant effect. Overprinting parameters influenced the tear-off strength in the order of printing speed > printing temperature > substrate temperature. High values of tear-off strength were found for the lowest printing speed, while there were no important differences found between the middle and upper values. With increasing printing and substrate temperatures, the tear-off strength increased linearly. The highest value of tear-off strength (0.84 MPa) was observed at a printing temperature, substrate temperature and printing speed of 250 °C, 80 °C and 2 mm/s, respectively.

Maximum power and the corresponding efficiency for a Carnot-like thermoelectric cycle based on fluctuation theorem.

Here, we investigate the maximum power and efficiency of thermoelectric generators through devising a set of protocols for the isothermal and adiabatic processes of thermoelectricity to build a Carnot-like thermoelectric cycle, with the analysis based on fluctuation theorem. The Carnot efficiency can be readily obtained for the quasistatic thermoelectric cycle with vanishing power. The maximum power-efficiency pair of the finite-time thermoelectric cycle is derived, which is found to have the identical form to that of Brownian motors characterized by the stochastic thermodynamics. However, it is of significant discrepancy compared to the linear-irreversible and endoreversible-thermodynamics based formulations. The distinction with the linear-irreversible-thermodynamics case could result from the difference in the definitions of Peltier and Seebeck coefficients in the thermoelectric cycle. As for the endoreversible thermodynamics, we argue the applicability of endoreversibility could be questionable for analyzing the Carnot-like thermoelectric cycle, due to the incompatibility of the endoreversible hypothesis that attributes the irreversibility to finite heat transfer with thermal reservoirs, though the distinction in the mathematical expressions can vanish with the assumption that the ratio of thermoelectric power factors at the high and low temperatures (γ) is equal to the square root of the temperature ratio, γ=sqrt[T_{L}/T_{H}] (this condition could significantly deviate from the practical case). Last, utilizing our models as a concise tool to evaluate the maximum power-efficiency pairs of realistic thermoelectric material, we present a case study on the n-type silicon.

Water-Assisted Contact Electrification Properties of Selected Polymers and Surface Functionalization Molecules: A Computational Study.

Motivated by the requirements of performance stability in environments of variable humidity, the focus of this study is on the effects and role of humidity-induced water molecules and ions in the contact electrification (CE) mechanisms of triboelectric materials. In particular, the compatibility of direct charge transfer-based CE and other generally known or proposed water molecules or OH/H3O ion-facilitated CE mechanisms was assessed for a set of high-performance polymeric materials and functionalization molecules. The first set of test mechanisms included OH/H3O ion adsorption at the low-humidity limit. The adsorption resulted in physisorption or H transfer involving reactions that were not fully compatible with charge affinity-driven CE reactions on the considered contact surfaces for both ions in terms of the potential increase of the resultant density of surface charge. An alternative mechanism, which yielded compatibility at a large humidity limit, consisted of free energy-driven segregation and separation of the ions. Further test mechanisms included water adsorption-induced charge transfer and two mechanisms pertinent to charged material transfer: adsorption modulation due to formation of water monolayers and water solvation-induced separation of polymer fragments. According to the obtained results, both mechanisms could be verified as viable contributors to enhanced charge transfer. Consequently, the results allowed for conclusions regarding the general applicability of different, water-assisted CE mechanisms and the selection of particular pairs of contact materials of similar type for optimum performance in humid environments.