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Ionic liquids (ILs) have emerged as viable solutions for developing new-age lubricants, both as neat lubricants and lubricant additives. Enabled by the presence of discrete ions, ILs have the possibility to render electrically conductive lubricants, which is a feasible strategy for developing lubricant systems compatible with modern e-drive conditions. However, this requires the characterization of the electrical properties of lubricants, which is a bottleneck for developing electrically conductive greases, given their complex architecture. This work introduces an electrochemical impedance spectroscopy measurement methodology to evaluate grease samples' electrical properties. Compared to the commonly used conductivity meters, this method, through its multi-frequency alternating current (AC) impedance approach, can effectively distinguish the individual contributions of the bulk and the sample-electrode interface to the measured electrical response. Impedance spectra of grease samples are obtained using an electrochemical cell with parallel plate electrodes, mounted on a temperature-controlled cell stand and coupled with a potentiostat. The grease's bulk conductivity is extracted by fitting the impedance data to relevant equivalent electrical circuits. The bulk conductivity of lithium complex grease doped with ILs is evaluated and compared to greases with conventional conductivity additives (copper powder and conductive carbon black). The analysis of temperature-dependent conductivity reveals the rather different conductivity mechanisms for different additives. For greases doped with ILs, a comparison against the electrical conductivity of neat ILs reveals that, in addition to the ion dissociation, the interaction of the ions with the different grease components (base oil, thickener) is crucial in defining the grease conductivity., Validerad;2024;Nivå 2;2024-03-28 (hanlid);Full text: CC BY License

Ionic liquids (ILs) have emerged as viable solutions for developing new-age lubricants, both as neat lubricants and lubricant additives. Enabled by the presence of discrete ions, ILs have the possibility to render electrically conductive lubricants, which is a feasible strategy for developing lubricant systems compatible with modern e-drive conditions. However, this requires the characterization of the electrical properties of lubricants, which is a bottleneck for developing electrically conductive greases, given their complex architecture. This work introduces an electrochemical impedance spectroscopy measurement methodology to evaluate grease samples' electrical properties. Compared to the commonly used conductivity meters, this method, through its multi-frequency alternating current (AC) impedance approach, can effectively distinguish the individual contributions of the bulk and the sample-electrode interface to the measured electrical response. Impedance spectra of grease samples are obtained using an electrochemical cell with parallel plate electrodes, mounted on a temperature-controlled cell stand and coupled with a potentiostat. The grease's bulk conductivity is extracted by fitting the impedance data to relevant equivalent electrical circuits. The bulk conductivity of lithium complex grease doped with ILs is evaluated and compared to greases with conventional conductivity additives (copper powder and conductive carbon black). The analysis of temperature-dependent conductivity reveals the rather different conductivity mechanisms for different additives. For greases doped with ILs, a comparison against the electrical conductivity of neat ILs reveals that, in addition to the ion dissociation, the interaction of the ions with the different grease components (base oil, thickener) is crucial in defining the grease conductivity., Validerad;2024;Nivå 2;2024-03-28 (hanlid);Full text: CC BY License

The deterioration of the environment and especially the crisis due to the availability of water, has led developing countries to advance in protection, avoiding the dumping of wastewater and monitoring quality. In the city of Medellín, the use of electrical conductivity as an indicator of water quality in the Aburrá-Medellín river was proposed as an alternative to explain and keep the community informed about how the river monitoring stations are doing through of colors and thus continue to raise awareness of the importance of caring for water. In order to study the spatial and temporal variations of the water quality in the river from the electrical conductivity indicator, and considering the categorical data obtained with the indicator, a number from 1 to 5 was assigned (very bad, bad , regular, acceptable and good quality, respectively). In these paper We used statistical methods as crosstabulation to describe relationships between the categorical variables through counts and multiple correspondence analysis for representing the associations between the factors affecting the wáter quality using the correspondence maps. It was found that low flows correspond to the most critical quality conditions, and although a deterioration is observed as the river flows downstream (between the monitoring stations) the influence of the water levels is greater. The statistical analysis showed a relatively high association of the quality indicator and the flows also, that the water quality deteriorates in the afternoon and in the final years of monitoring in low flows., El deterioro del ambiente y en especial la crisis por la disponibilidad de agua, ha llevado a que los países en vía de desarrollo avancen en la protección, evitando el vertimiento de aguas residuales y en el seguimiento a la calidad. En la ciudad de Medellín, se propuso el uso de la conductividad eléctrica como un indicador de calidad de agua en el río Aburrá-Medellín como una alternativa para explicar y mantener informada a la comunidad acerca de cómo están las estaciones de monitoreo del río a través de colores y así continuar sensibilizando en la importancia del cuidado del agua. Con el fin de estudiar las variaciones espaciales y temporales de la calidad del agua en el río a partir del indicador conductividad eléctrica, y considerando los datos categóricos que se obtienen con el indicador, se asignó un número de 1 a 5 (muy mala, mala, regular, aceptable y buena calidad, respectivamente). En este artículo utilizamos métodos estadísticos como la tabulación cruzada para describir las relaciones entre las variables categóricas a través de conteos y análisis de correspondencia múltiple para representar las asociaciones entre los factores que afectan la calidad del agua usando los mapas de correspondencia. Se encontró que los caudales bajos corresponden a las condiciones de calidad más críticas, y aunque se observa un deterioro a medida que el río fluye aguas abajo (entre las estaciones de monitoreo) la influencia de los niveles de agua es mayor. El análisis estadístico mostró una asociación relativamente alta del indicador de calidad y los caudales, además, que la calidad del agua se deteriora en la tarde y en los años finales de monitoreo en caudales bajos.

With a rapid shift in our society to e-mobility, novel grease formulations for machine efficiency, reliability, and availability are even more important than ever. Greases are expected to provide low friction and noise while extending the machine service life. Whether the grease should be electrically conductive or not remains a subject of debate. The chapter discusses grease architecture and how to tune it in view of the latest and upcoming specification requirements. Selection strategies for base oils, thickeners, and additives are discussed. Integrating these components in the final formulation is a delicate process of balancing required properties that can be contradictory. Grease testing methods are addressed reflecting the need for complementary characterization of grease energy efficiency, conductivity, and protection against fretting. The arguments are made in connection to the representative transmission components., Part of ISBN 9780443140747, 9780443140754QC 20240820

Adding Fe3O4 nanoparticles to composites of [Fe(Htrz)2(trz)](BF4) spin-crossover polymer and polyaniline (PANI) drives a phase separation of both and restores the molecular structure and cooperative effects of the spin-crossover polymer without compromising the increased conductivity gained through the addition of PANI. We observe an increased on-off ratio for the DC conductivity owing to an enlarged off state resistivity and a 20 times larger AC conductivity of the on state compared with DC values. The Fe3O4 nanoparticles, primarily confined to the [Fe(Htrz)2(trz)](BF4) phase, are ferromagnetically coupled to the local moment of the spin-crossover molecule suggesting the existence of an exchange interaction between both components.

In this work, novel two-dimensional BC2X (X = N, P, As) monolayers with X atoms out of the B–C plane, are predicted by means of the density functional theory. The structural, electronic, optical, photocatalytic and thermoelectric properties of the BC2X monolayers have been investigated. Stability evaluation of the BC2X single-layers is carried out by phonon dispersion, ab-initio molecular dynamics (AIMD) simulation, elastic stability, and cohesive energies study. The mechanical properties reveal all monolayers considered are stable and have brittle nature. The band structure calculations using the HSE06 functional reveal that the BC2N, BC2P and BC2As are semiconducting monolayers with indirect bandgaps of 2.68 eV, 1.77 eV and 1.21 eV, respectively. The absorption spectra demonstrate large absorption coefficients of the BC2X monolayers in the ultraviolet range of electromagnetic spectrum. Furthermore, we disclose the BC2N and BC2P monolayers are potentially good candidates for photocatalytic water splitting. The electrical conductivity of BC2X is very small and slightly increases by raising the temperature. Electron doping may yield greater electric productivity of the studied monolayers than hole doping, as indicated by the larger power factor in the n-doped region compared to the p-type region. These results suggest that BC2X (X = N, P, As) monolayers represent a new promising class of 2DMs for electronic, optical and energy conversion systems. © 2022, The Author(s)., This work was supported by TUBITAK ULAK-BIM, at the High Performance and Grid Computing Center (TR-Grid e-Infrastructure)., This study was funded by National Research Foundation of Korea (No. NRF-2015M2B2A4033123)., National Research Foundation of Korea, NRF: NRF-2015M2B2A4033123

Electrically conductive biomaterials direct cell behavior by capitalizing on the effect of bioelectricity in tissue homeostasis and healing. Many studies have leveraged conductive biomaterials to influence cells and improve tissue healing, even in the absence of external stimulation. However, most studies using electroactive materials neglect characterizing how the inclusion of conductive additives affects the material's mechanical properties, and the interplay between substrate electrical and mechanical properties on cell behavior is poorly understood. Furthermore, mechanisms dictating how electrically conductive materials affect cell behavior in the absence of external stimulation are not explicit. In this study, we developed a mechanically and electrically tunable conductive hydrogel using agarose and the conductive polymer PEDOT:PSS. Under certain conditions, we observed that the hydrogel physical and electrical properties were decoupled. We then seeded human mesenchymal stromal cells (MSCs) onto the hydrogels and observed enhanced adhesion and spreading of MSCs on conductive substrates, regardless of the hydrogel mechanical properties, and despite the gels having no cell-binding sites. To explain this observation, we measured protein interaction with the gels and found that charged proteins adsorbed significantly more to conductive hydrogels. These data demonstrate that conductivity promotes cell adhesion, likely by facilitating increased adsorption of proteins associated with cell binding, providing a better understanding of the mechanism of action of electrically conductive materials.

Despite numerous efforts to generate mature human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs), cells often remain immature, electrically isolated, and may not reflect adult biology. Conductive polymers are attractive candidates to facilitate electrical communication between hPSC-CMs, especially at sub-confluent cell densities or diseased cells lacking cell-cell junctions. Here we electrospun conductive polymers to create a conductive fiber mesh and assess if electrical signal propagation is improved in hPSC-CMs seeded on the mesh network. Matrix characterization indicated fiber structure remained stable over weeks in buffer, scaffold stiffness remained near in vivo cardiac stiffness, and electrical conductivity scaled with conductive polymer concentration. Cells remained adherent and viable on the scaffolds for at least 5 days. Transcriptomic profiling of hPSC-CMs cultured on conductive substrates for 3 days showed upregulation of cardiac and muscle-related genes versus non-conductive fibers. Structural proteins were more organized and calcium handling was improved on conductive substrates, even at sub-confluent cell densities; prolonged culture on conductive scaffolds improved membrane depolarization compared to non-conductive substrates. Taken together, these data suggest that blended, conductive scaffolds are stable, supportive of electrical coupling in hPSC-CMs, and promote maturation, which may improve our ability to model cardiac diseases and develop targeted therapies.

Structural supercapacitors hold promise to expand the energy capacity of a system by integrating load-bearing and energy-storage functions in a multifunctional structure, resulting in weight savings and safety improvements. Here, we develop strategies based on interfacial engineering to advance multifunctional efficiency. The structural electrodes were reinforced by coating carbon-fiber weaves with a uniquely stable conjugated redox polymer and reduced graphene oxide that raised pseudocapacitive capacitance and tensile strength. The solid polymer electrolyte was tuned to a gradient configuration, where it facilitated high ionic conductivity at the electrode-electrolyte interfaces and transitioned to a composition with high mechanical strength in the bulk for load support. The gradient design enabled the multilayer structural supercapacitors to reach state-of-the-art performance matching the level of monofunctional supercapacitors. In situ electrochemical-mechanical measurements established the device durability under mechanical loads. The structural supercapacitor was made into the hull of a model boat to demonstrate its multifunctionality.

In this work, novel two-dimensional BC2X (X = N, P, As) monolayers with X atoms out of the B–C plane, are predicted by means of the density functional theory. The structural, electronic, optical, photocatalytic and thermoelectric properties of the BC2X monolayers have been investigated. Stability evaluation of the BC2X single-layers is carried out by phonon dispersion, ab-initio molecular dynamics (AIMD) simulation, elastic stability, and cohesive energies study. The mechanical properties reveal all monolayers considered are stable and have brittle nature. The band structure calculations using the HSE06 functional reveal that the BC2N, BC2P and BC2As are semiconducting monolayers with indirect bandgaps of 2.68 eV, 1.77 eV and 1.21 eV, respectively. The absorption spectra demonstrate large absorption coefficients of the BC2X monolayers in the ultraviolet range of electromagnetic spectrum. Furthermore, we disclose the BC2N and BC2P monolayers are potentially good candidates for photocatalytic water splitting. The electrical conductivity of BC2X is very small and slightly increases by raising the temperature. Electron doping may yield greater electric productivity of the studied monolayers than hole doping, as indicated by the larger power factor in the n-doped region compared to the p-type region. These results suggest that BC2X (X = N, P, As) monolayers represent a new promising class of 2DMs for electronic, optical and energy conversion systems. © 2022, The Author(s)., This work was supported by TUBITAK ULAK-BIM, at the High Performance and Grid Computing Center (TR-Grid e-Infrastructure)., This study was funded by National Research Foundation of Korea (No. NRF-2015M2B2A4033123)., National Research Foundation of Korea, NRF: NRF-2015M2B2A4033123

The next generation of high-power electronic devices is expected to exhibit improved heat dissipation capabilities despite their smaller size. Current studies have investigated the utilization of hybrid fillers, our study introduces a novel approach by combining boron nitride (BN) and surface-enhanced flake graphite (G), both of which possess a platelet-like structure, to develop a thermally conductive grease. The grease shows an exceptionally high thermal conductivity of 2.21 W/mK and an extremely low electrical conductivity of 7.3×10-6 S/m. The viscosity of the grease is measured at 149 Pa·s. By incorporating hybrid fillers with a significantly high aspect ratio into EPON 828, a notable reduction of interfacial thermal resistance is observed, which is attributed to the formation of an effective pathway for phonon transfer facilitated by the unique characteristics of the hybrid fillers. Various theoretical models are employed to corroborate the experimental data, which facilitates substantiating the fundamental principles underlying the enhanced thermal conductivity of the prepared thermal grease.

The production of green hydrogen in water electrolyzers is limited by the oxygen evolution reaction (OER). State-of-the-art electrocatalysts are based on Ir. Ru electrocatalysts are a suitable alternative provided their performance is improved. Here we show that low-Ru-content pyrochlores (R2MnRuO7, R = Y, Tb and Dy) display high activity and durability for the OER in acidic media. Y2MnRuO7 is the most stable catalyst, displaying 1.5 V at 10 mA cm−2 for 40 h, or 5000 cycles up to 1.7 V. Computational and experimental results show that the high performance is owed to Ru sites embedded in RuMnOx surface layers. A water electrolyser with Y2MnRuO7 (with only 0.2 mgRu cm−2) reaches 1 A cm−2 at 1.75 V, remaining stable at 200 mA cm−2 for more than 24 h. These results encourage further investigation on Ru catalysts in which a partial replacement of Ru by inexpensive cations can enhance the OER performance. © 2023, The Author(s).

Strain measurements are vital for monitoring the load-bearing capacity and safety of structures. A common approach is to affix strain gages onto structural surfaces. On the other hand, most aerospace, automotive, civil, and mechanical structures are painted and coated, often with many layers, prior to their deployment. There is an opportunity to design smart and multifunctional paints that can be directly pre-applied onto structural surfaces to serve as a sensing layer among their other layers of functional paints. Therefore, the objective of this study was to design a strain-sensitive paint that can be used for structural monitoring. Carbon nanotubes (CNT) were dispersed in paint by high-speed shear mixing, while paint thinner was employed for adjusting the formulation's viscosity and nanomaterial concentration. The study started with the design and fabrication of the CNT-based paint. Then, the nanocomposite paint's electromechanical properties and its sensitivity to applied strains were characterized. Third, the nanocomposite paint was spray-coated onto patterned substrates to form "Sensing Meshes" for distributed strain monitoring. An electrical resistance tomography (ERT) measurement strategy and algorithm were utilized for reconstructing the conductivity distribution of the Sensing Meshes, where the magnitude of conductivity (or resistivity) corresponded to the magnitude of strain, while strain directionality was determined based on the strut direction in the mesh.

Strain measurements are vital for monitoring the load-bearing capacity and safety of structures. A common approach is to affix strain gages onto structural surfaces. On the other hand, most aerospace, automotive, civil, and mechanical structures are painted and coated, often with many layers, prior to their deployment. There is an opportunity to design smart and multifunctional paints that can be directly pre-applied onto structural surfaces to serve as a sensing layer among their other layers of functional paints. Therefore, the objective of this study was to design a strain-sensitive paint that can be used for structural monitoring. Carbon nanotubes (CNT) were dispersed in paint by high-speed shear mixing, while paint thinner was employed for adjusting the formulation's viscosity and nanomaterial concentration. The study started with the design and fabrication of the CNT-based paint. Then, the nanocomposite paint's electromechanical properties and its sensitivity to applied strains were characterized. Third, the nanocomposite paint was spray-coated onto patterned substrates to form "Sensing Meshes" for distributed strain monitoring. An electrical resistance tomography (ERT) measurement strategy and algorithm were utilized for reconstructing the conductivity distribution of the Sensing Meshes, where the magnitude of conductivity (or resistivity) corresponded to the magnitude of strain, while strain directionality was determined based on the strut direction in the mesh.

Continuous, one-dimensional (1D) stretchable conductors have attracted significant attention for the development of wearables and soft-matter electronics. Through the use of advanced spinning, printing, and textile technologies, 1D stretchable conductors in the forms of fibers, wires, and yarns can be designed and engineered to meet the demanding requirements for different wearable applications. Several crucial parameters, such as microarchitecture, conductivity, stretchability, and scalability, play essential roles in designing and developing wearable devices and intelligent textiles. Methodologies and fabrication processes have successfully realized 1D conductors that are highly conductive, strong, lightweight, stretchable, and conformable and can be readily integrated with common fabrics and soft matter. This review summarizes the latest advances in continuous, 1D stretchable conductors and emphasizes recent developments in materials, methodologies, fabrication processes, and strategies geared toward applications in electrical interconnects, mechanical sensors, actuators, and heaters. This review classifies 1D conductors into three categories on the basis of their electrical responses: (1) rigid 1D conductors, (2) piezoresistive 1D conductors, and (3) resistance-stable 1D conductors. This review also evaluates the present challenges in these areas and presents perspectives for improving the performance of stretchable 1D conductors for wearable textile and flexible electronic applications.

This article aims to perform a space-time analysis of the electrical conductivity readings measured in the Aburrá - Medellín river, in the period 2006-2020, through the monitoring network of water resources in the region - RedRío, to evaluate the feasibility of using it as an indicator of water quality in the three automatic monitoring stations that are part of this network.The classification of the flow regime was carried out considering the historical record of flows measured between 2004 and 2020 in the region's water resources monitoring net-work - RedRío. Then, to evaluate if there were statistically significant differences between the electrical conductivity measured in the stations and for the measurements in the three flow ranges, the non-parametric Kruskal Wallis test was performed, since the assumptions required for an analysis of variance were not met. Finally, to make the state of the river more visible from the electrical conductivity measurements, a categorization by ranges (quartiles) and color assignment is proposed, as established in the ICA water quality indices.As a result of this study, two classifications of electrical conductivity expressed in five color ranges are proposed, as well as the quality index for surface water – ICA-. Finally, the rea-dings obtained in the automatic stations from August 2019 to March 2020 are reviewed and classification ranges for these stations are adjusted.This research highlights the proposal to introduce the use of this variable as an indicator of water quality, to illustrate and continuously inform the community about the state of the Aburrá- Medellín river through a color code, to sensitize the inhabitants of the basin on its protection, care, and the importance of efficiently use and save water., Este artículo tiene como objetivo realizar un análisis espacio-temporal de las lecturas de con-ductividad eléctrica medidas en el río Aburrá - Medellín, en el período 2006-2020, a través de la red de monitoreo de los recursos hídricos de la región - RedRío, para evaluar la factibilidad de su uso como indicador de la calidad del agua en las tres estaciones de monitoreo automático que forman parte de esta red.La clasificación del régimen de caudales se realizó considerando el registro histórico de caudales medidos entre 2004 y 2020 en la red de monitoreo de recursos hídricos de la región - RedRío. Luego, para evaluar si existían diferencias estadísticamente significativas entre la conductividad eléctrica medida en las estaciones y para las medidas en los tres rangos de flujo, se realizó la prueba no paramétrica de Kruskal Wallis, ya que no se cumplieron los supuestos requeridos para un análisis de varianza. Finalmente, para hacer más visible el estado del río a partir de las medidas de conductividad eléctrica, se propone una categorización por rangos (cuartiles) y asignación de colores, según lo establecido en los índices de calidad del agua – ICA.Como resultado de este estudio, se proponen dos clasificaciones de conductividad eléctrica expresadas en cinco gamas de colores, así como el índice de calidad del agua superficial – ICA-. Finalmente, se revisan las lecturas obtenidas en las estaciones automáticas de agosto de 2019 a marzo de 2020 y se ajustan los rangos de clasificación de estas estaciones.Esta investigación destaca la propuesta de introducir el uso de esta variable como indicador de la calidad del agua, para ilustrar e informar continuamente a la comunidad sobre el estado del río Aburrá-Medellín a través de un código de colores, para sensibilizar a los habitantes de la cuenca sobre su protección, cuidado y la importancia de usar y ahorrar agua de manera eficiente.

Electronic waste carries energetic costs and an environmental burden rivaling that of plastic waste due to the rarity and toxicity of the heavy-metal components. Recyclable conductive composites are introduced for printed circuits formulated with polycaprolactone (PCL), conductive fillers, and enzyme/protectant nanoclusters. Circuits can be printed with flexibility (breaking strain ≈80%) and conductivity (≈2.1 × 104 S m-1 ). These composites are degraded at the end of life by immersion in warm water with programmable latency. Approximately 94% of the functional fillers can be recycled and reused with similar device performance. The printed circuits remain functional and degradable after shelf storage for at least 7 months at room temperature and one month of continuous operation under electrical voltage. The present studies provide composite design toward recyclable and easily disposable printed electronics for applications such as wearable electronics, biosensors, and soft robotics.

Conductive biomaterials provide an important control for engineering neural tissues, where electrical stimulation can potentially direct neural stem/progenitor cell (NS/PC) maturation into functional neuronal networks. It is anticipated that stem cell-based therapies to repair damaged central nervous system (CNS) tissues and ex vivo, "tissue chip" models of the CNS and its pathologies will each benefit from the development of biocompatible, biodegradable, and conductive biomaterials. Here, technological advances in conductive biomaterials are reviewed over the past two decades that may facilitate the development of engineered tissues with integrated physiological and electrical functionalities. First, one briefly introduces NS/PCs of the CNS. Then, the significance of incorporating microenvironmental cues, to which NS/PCs are naturally programmed to respond, into biomaterial scaffolds is discussed with a focus on electrical cues. Next, practical design considerations for conductive biomaterials are discussed followed by a review of studies evaluating how conductive biomaterials can be engineered to control NS/PC behavior by mimicking specific functionalities in the CNS microenvironment. Finally, steps researchers can take to move NS/PC-interfacing, conductive materials closer to clinical translation are discussed.

Cellular lattice structures possess high strength-to-weight ratios suitable for advanced lightweight engineering applications. However, their quality and mechanical performance can degrade because of defects introduced during manufacturing or in-service. Their complexity and small length scale features make defects difficult to detect using conventional nondestructive evaluation methods. Here we propose a current injection-based method, electrical resistance tomography (ERT), that can be used to detect damaged struts in conductive cellular lattice structures with their intrinsic electromechanical properties. The reconstructed conductivity distributions from ERT can reveal the severity and location of damaged struts without having to probe each strut. However, the low central sensitivity of ERT may result in image artifacts and inaccurate localization of damaged struts. To address this issue, this study introduces an absolute, high throughput, conductivity reconstruction algorithm for 3D ERT. The algorithm incorporates a strut-based normalized sensitivity map to compensate for lower interior sensitivity and suppresses reconstruction artifacts. Numerical simulations and experiments on fabricated representative cellular lattice structures were performed to verify the ability of ERT to quantitatively identify single and multiple damaged struts. The improved performance of this method compared with classical ERT was observed, based on greatly decreased imaging and reconstructed value errors.

Implantable cardiac patches and injectable hydrogels are among the most promising therapies for cardiac tissue regeneration following myocardial infarction. Incorporating electrical conductivity into these patches and hydrogels is found to be an efficient method to improve cardiac tissue function. Conductive nanomaterials such as carbon nanotube, graphene oxide, gold nanorod, as well as conductive polymers such as polyaniline, polypyrrole, and poly(3,4-ethylenedioxythiophene):polystyrene sulfonate are appealing because they possess the electroconductive properties of semiconductors with ease of processing and have potential to restore electrical signaling propagation through the infarct area. Numerous studies have utilized these materials for regeneration of biological tissues that possess electrical activities, such as cardiac tissue. In this review, recent studies on the use of electroconductive materials for cardiac tissue engineering and their fabrication methods are summarized. Moreover, recent advances in developing electroconductive materials for delivering therapeutic agents as one of emerging approaches for treating heart diseases and regenerating damaged cardiac tissues are highlighted.

Real-time chemical sensing is crucial for applications in environmental and health monitoring1. Biosensors can detect a variety of molecules through genetic circuits that use these chemicals to trigger the synthesis of a coloured protein, thereby producing an optical signal2-4. However, the process of protein expression limits the speed of this sensing to approximately half an hour, and optical signals are often difficult to detect in situ5-8. Here we combine synthetic biology and materials engineering to develop biosensors that produce electrical readouts and have detection times of minutes. We programmed Escherichia coli to produce an electrical current in response to specific chemicals using a modular, eight-component, synthetic electron transport chain. As designed, this strain produced current following exposure to thiosulfate, an anion that causes microbial blooms, within 2 min. This amperometric sensor was then modified to detect an endocrine disruptor. The incorporation of a protein switch into the synthetic pathway and encapsulation of the bacteria with conductive nanomaterials enabled the detection of the endocrine disruptor in urban waterway samples within 3 min. Our results provide design rules to sense various chemicals with mass-transport-limited detection times and a new platform for miniature, low-power bioelectronic sensors that safeguard ecological and human health.

Currently, many intelligent materials applied in textiles have been developed, such as photonic fibers, shape memory materials, conductive materials, phase change materials, chromic materials, mechanical responsive materials, intelligent coating/membranes, micro and nanomaterials and piezoelectric materials. With the rapid development of the electrical and, particularly, the electronics industry, flexible electrically conducting and semiconducting materials, such as conductive polymers, conductive fibers, threads, yarns, coatings and ink, are receiving widespread attention. They are playing a more and more important role in realizing lightweight, wireless and wearable interactive electronic textiles. The objective of this thesis was the study and manufacture of a humidity detector fabric which acts as an alarm when a liquid gets in touch with it. Therefore, e-textiles also known as intelligent textiles, are smart materials that have an electronic or conductive compound in them, such as conductive yarns, conductive coatings, sensors, etc. All the technologies to produce a sensor were studied in order to choose the best option to recreate a prototype of a humidity sensor.The woven option with conductive threads was chosen due to the lackof humidity detectors made by this method. With the help of a fabric design software called Penelope Cad Systems.The fabric has been able to produce a sort of a humidity detector prototype with a high sensitivity. Furthermore, a study of functionality of the fabric and durability of the conductive yarns has been made. The tests of durability are abrasion and pilling by the Martindale method. Also a washing test has been made to observe if conductives yarns keep their properties. These tests were chosen because this fabric was thought to be a kind of bedspread or bed sheet for a medical purpose. Finally, the results of the fabric developed have been presented in order to discern if it is functional and viable or not. These results can b

It is common knowledge that textiles and textile products are available in different forms along the textile chain. However, right now, all the attention is paid to the relationship between these materials and the most recent developments in the world of electronics. When a garment is implementing electronic components, ranging from sensors to conductor paths, that are applied or integrated into the textile surface, it’s commonly called an E-Textile. Nowadays there is a continuous demand for these products because they can satisfy a great extent of needs without interfering too much with the user’s life or without the obligation of modifying too much the original product in the beginning. This study, however, focuses on analyzing the interaction and interactivity which allows electronic communication between the components present in the textiles. It is believed that there is a knowledge gap in these most recent developments. In this paper, a literature investigation is carried out using various databases, which resulted in different contributions to the researched subjects. Also, an overview of materials, production technologies and testing methods is given. The concepts of smart and e-textile, textile structure, conductive materials, electronic communication and connection are classified. The influencing factors on the properties of the material structure are presented and a discussion is made referring to the potentials and challenges related to e-textiles. Finally, a brief consideration of sustainability and environmental aspects is done and, in the end, the main conclusions of the investigation are stated. The main focus of the research lies in defining processes and material properties for improving connection techniques between the textiles and the electronic components, and also between the components themselves. Only limited research will be conducted on simulating the behavior of these technologies. Various ideas for applications exist, starting from ones

With the growth of the population and the improvement of people's quality of life, the consumption of textiles is increasing, but the number of textiles recycled and reused is relatively small. Especially in recent years, there have been more and more text iles containing conductive fibres, and their recycling methods are quite different from ordinary fibres. Therefore, reasonable recycling is required to avoid waste of resources. In this paper, a conductive nonwoven fabric is constructed by stainless steel fibres, and its feasibility is analyzed to further explore the feasibility of using recycled stainless steel fibres. The specific research contents are as follows: (1) Desk work Summarize the current types of conductive fibres, preparation methods, and app lications. The most suitable conductive fibres(stainless steel fibre) are selected by analyzing and comparing the electrical properties of these conductive fibres, the degree of impurities in their preparation, and the cost. The nonwoven fabric preparatio n method used in this experiment was analyzed, and the feasibility of using stainless steel fibres to construct conductive nonwoven fabrics was further determined by considering the matching degree of the process flow with the stainless steel fibres. Summa rize the methods for recycling and reusing conductive fibres, and summarize the types of products containing conductive fibres, especially stainless steel fibres, as potential waste sources. And put forward a plan for recycling and reusing these products w hen discarded. Summarize the current application of conductive cement and the types of conductive fibres suitable for it. Consider the possibility of conductive nonwovens as reinforcing materials to impart conductive properties to cement. (2) Experiment pa rt By comparing the conductive properties of nonwoven fabrics with different stainless steel fibre content and different fibre bonding methods, it can be seen that the higher the content of stainless ste

An electrically conductive textile conducts an electrical current or supplies an electric field to a device. They are usually part of a smart textile system, a textile-based system that exhibits a reaction either to changes in its surroundings/environment or to an external signal/input. Smart textile systems are also known as smart or intelligent textile/garment. Wearing apparel manufacturing companies are proposing smart garments manufactured from smart textiles for outdoor wear, sportswear, lifestyle, and urban life but conductive textiles have not yet reached mass-market consumers as initially forecasted; the endconsumer is not confident to invest in a costly garment with yet unclear cleaning requirements and a potential loss of functional properties after domestic laundry. This thesis studies the influence of domestic washing and abrasion on conductive fabrics and the effects on their surface electric resistance. In addition, it will also be observed the surface change after the abrasion in order to link any physical surface modification with the experimental findings. The specimens to be analysed are conductive warp knitted structure and a non-woven conductive structure combined with a conventional knitted structure forming a 2D conductive composite by lamination; a conductive TPU film laminated with a conventional textile knitted structure and an electronic circuit printed conductive ink and transferred by heat press onto a conventional knit structure; all six 2D conductive specimens have the same conventional ground fabric: a warp knit structure of polyamide and elastane. The conductive 2D materials will be exposed to washing and abrasion tests and their linear surface resistance will be measured at the initial stage of the experiment and compared with their conductive properties during and after the completion of the experimental tests. The work aims to contribute to a better understanding of the effects of domestic laundry and abrasion on the surface resist

The direct current (dc) conductivity and emergent functionalities at ferroelectric domain walls are closely linked to the local polarization charges. Depending on the charge state, the walls can exhibit unusual dc conduction ranging from insulating to metallic-like, which is leveraged in domain-wall-based memory, multilevel data storage, and synaptic devices. In contrast to the functional dc behaviors at charged walls, their response to alternating currents (ac) remains to be resolved. Here, we reveal ac characteristics at positively and negatively charged walls in ErMnO3, distinctly different from the response of the surrounding domains. By combining voltage-dependent spectroscopic measurements on macroscopic and local scales, we demonstrate a pronounced nonlinear response at the electrode-wall junction, which correlates with the domain-wall charge state. The dependence on the ac drive voltage enables reversible switching between uni- and bipolar output signals, providing conceptually new opportunities for the application of charged walls as functional nanoelements in ac circuitry.

High‐resolution data collection of the urban stormwater network is crucial for future asset management and illicit discharge detection, but often too expensive as sensors and ongoing frequent maintenance works are not affordable. We developed an integrated water depth, electrical conductivity (EC), and temperature sensor that is inexpensive (USD 25), low power, and easily implemented in urban drainage networks. Our low‐cost sensor reliably measures the rate‐of‐change of water level without any re‐calibration by comparing with industry‐standard instruments such as HACH and HORIBA’s probes. To overcome the observed drift of level sensors, we developed an automated re‐calibration approach, which significantly improved its accuracy. For applications like monitoring stormwater drains, such an approach will make higher‐resolution sensing feasible from the budget control considerations, since the regular sensor re‐calibration will no longer be required. For other applications like monitoring wetlands or wastewater networks, a manual re‐calibration every two weeks is required to limit the sensor’s inaccuracies to ±10 mm. Apart from only being used as a calibrator for the level sensor, the conductivity sensor in this study adequately monitored EC between 0 and 10 mS/cm with a 17% relative uncertainty, which is sufficient for stormwater monitoring, especially for real‐time detection of poor stormwater quality inputs. Overall, our proposed sensor can be rapidly and densely deployed in the urban drainage network for revolutionised high‐density monitoring that cannot be achieved before with high‐end loggers and sensors.

Several types of electrode materials have been developed for high–performance supercapacitors. Most of the relevant studies have focused on the discovery of new atomic structures and paid limited attention to the effect of heterostructures in supercapacitor electrodes, which has long hindered the fundamental understanding of the use of hybrid materials in supercapacitors. In this study, a novel heterostructure based on perovskite oxide (LaNiO3) nanosheets and polyazulene was synthesized. The as–prepared heterostructure–based supercapacitor exhibited a specific capacitance of up to 464 F g−1 at a high current density of 2 A g−1 in 1–ethyl–3–methylimidazolium tetrafluoroborate. In a symmetric supercapacitor, this heterostructure delivered an energy density of up to 56.4 Wh kg−1 at a power density of 1100 W kg−1. Both LaNiO3 and polyazulene contributed pseudocapacitance and dominated the performance. Unexpectedly, electric double–layer capacitance was found to contribute in this system. Density functional theory calculations indicated that the advantage of the high electrical conductivity of the heterostructure benefited the supercapacitor operation. Electrochemical quartz crystal microbalance analysis revealed that the fast ion flux and adsorption boosted performance. The high intrinsic electrical conductivity and improved stability make this heterostructure a promising electrode material candidate for supercapacitors., QC 20220314

The direct current (dc) conductivity and emergent functionalities at ferroelectric domain walls are closely linked to the local polarization charges. Depending on the charge state, the walls can exhibit unusual dc conduction ranging from insulating to metallic-like, which is leveraged in domain-wall-based memory, multilevel data storage, and synaptic devices. In contrast to the functional dc behaviors at charged walls, their response to alternating currents (ac) remains to be resolved. Here, we reveal ac characteristics at positively and negatively charged walls in ErMnO3, distinctly different from the response of the surrounding domains. By combining voltage-dependent spectroscopic measurements on macroscopic and local scales, we demonstrate a pronounced nonlinear response at the electrode-wall junction, which correlates with the domain-wall charge state. The dependence on the ac drive voltage enables reversible switching between uni- and bipolar output signals, providing conceptually new opportunities for the application of charged walls as functional nanoelements in ac circuitry.

Spin crossover (SCO) molecules are promising nanoscale magnetic switches due to their ability to modify their spin state under several stimuli. However, SCO systems face several bottlenecks when downscaling into nanoscale spintronic devices: their instability at the nanoscale, their insulating character and the lack of control when positioning nanocrystals in nanodevices. Here we show the encapsulation of robust Fe-based SCO molecules within the 1D cavities of single-walled carbon nanotubes (SWCNT). We find that the SCO mechanism endures encapsulation and positioning of individual heterostructures in nanoscale transistors. The SCO switch in the guest molecules triggers a large conductance bistability through the host SWCNT. Moreover, the SCO transition shifts to higher temperatures and displays hysteresis cycles, and thus memory effect, not present in crystalline samples. Our results demonstrate how encapsulation in SWCNTs provides the backbone for the readout and positioning of SCO molecules into nanodevices, and can also help to tune their magnetic properties at the nanoscale.

The main goal of this work is to study the physical, structural, optical, and electrical properties of alkali zinc phosphate glasses doped with CoO oxide with the general formula 10Li2O-xCoO-(40-x)ZnO?50P2O5. Using the standard melt-quench technique, a large glass-forming region is obtained, and up to 40 mol% CoO doped glasses are prepared. XRD diffraction confirmed the amorphous nature of these materials. Density, molar volume, and the glass transition temperature (Tg) are composition-dependent. Infrared (IR) spectroscopy is performed to study the structural approach. It is observed that the substitution of ZnO by CoO oxide in the glassy framework induces some structural modifications. The UV?Visible spectra of the CoO-doped glasses show visible absorption bands in the region 400?700 nm which are related to the coexistence of cobalt in divalent and trivalent states. The crystallization behaviour of the samples is performed by submitting the glasses to controlled heat treatments and the crystalline phases obtained are identified by X-Ray diffraction (XRD). The kinetic of the crystallization is carried out by employing the thermal analysis (DSC) technique. The crystallization process is discussed regarding the obtained activation energy (Ec) and Avrami parameter (n). The Vickers hardness values of the glasses and the glass-ceramics are determined and discussed according to the bond strengths. The electrical conductivity of these materials is investigated over a large frequency domain at various temperatures. It is found that the electric conductivity decreases with increasing cobalt content. It is also noted that the conductivity of each glass-ceramic is reduced in comparison with that of its mother glass. The frequency-dependent of the conductivity follows Jonscher?s power law and the correlated barrier hopping mechanisms (CBH) was appropriate for the conduction process inside the glasses. The electrical modulus formalism is applied to the electric data in order to

The present study demonstrates the reduction in the dielectric loss at room temperature from 0.149 to 0.027 in the composite of (NdFeO3)0.1−(Ba0.7Sr0.3TiO3)0.9 as compared to the undoped Ba0.7Sr0.3TiO3 and correlates with the charge compensation due to the ionic substitutions for both A site (NdBa) and B (FeTi) site generated excess electrons, localized hole states and robust oxygen vacancies (VO) along with different cationic oxidation states. The VO mediated F center charge transfer mechanism i.e., bound magnetic polaronic behaviour and defect complex generated between acceptors and ionized VO reduce electrical conductivity and loss factor. The presence of weak ferromagnetism in the M-H loop reconfirms the F center exchange mechanism in mixed phase symmetry. The activation energy calculated from impedance spectroscopy, electrical modulus and electrical conductivity analysis supports the presence of doubly ionized VO. Further, density functional theory based first principle calculation manifests that the impurity induced depopulation of valence band edge electrons into a single spin up channel which distorts TiO6 octahedra with fluctuating bond length and Ti 3deg orbital splitting observed in decomposed density of states for accommodating excess electrons. These trapped and accommodated electrons reduce the effective electron concentration which in turn decreases the electrical conductivity and loss factor., QC 20220810

Certain applications require a contactless measurement to eliminate the risk of sensorinduced sample contamination. Examples can be found in chemical process control, biotechnology or medical technology. For instance, in critically ill patients requiring renal replacement therapy, continuous in‐line monitoring of blood conductivity as a measure for sodium should be considered. A differential inductive sensing system based on a differential transformer using a specific flow chamber has already proven suitable for this application. However, since the blood in renal replacement therapy is carried in plastic tubing, a direct measurement through the tubing offers a contactless method. Therefore, in this work we present a differential transformer for measuring directly through electrically non‐conductive tubing by winding the tube around the ferrite core of the transformer. Here, the dependence of the winding type and the number of turns of the tubing on the sensitivity has been analyzed by using a mathematical model, simulations and experimental validation. A maximum sensitivity of 364.9 mV/mol/L is measured for radial winding around the core. A longitudinal winding turns out to be less effective with 92.8 mV/mol/L. However, the findings prove the ability to use the differential transformer as a truly contactless sensing system. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

Poly(3,4-ethylenedioxythiophene) (PEDOT) plays a key role in the field of electrically conducting materials, despite its poor solubility and processability. Various molecules and polymers carrying sulfonic groups can be used to enhance PEDOT’s electrical conductivity. Among all, sul-fonated polyarylether sulfone (SPAES), prepared via homogenous synthesis with controlled degree of sulfonation (DS), is a very promising PEDOT doping agent. In this work, PEDOT was synthesized via high-concentration solvent-based emulsion polymerization using 1% w/w of SPAES with different DS as dopant. It was found that the PEDOT:SPAESs obtained have improved solubility in the chosen reaction solvents, i.e., N, N-dimethylformamide, dimethylacetamide, dimethyl sulfoxide, and N-methyl-2-pyrrolidone and, for the first time, the role of doping agent, DS and polymerization solvents were investigated analyzing the electrical properties of SPAESs and PEDOT:SPAES samples and studying the different morphology of PEDOT-based thin films. High DS of SPAES, i.e., 2.4 meq R-SO3− × g−1 of polymer, proved crucial in enhancing PEDOT’s electrical conductivity. Furthermore, the DMSO capability to favor PEDOT and SPAES chains rearrangement and interaction results in the formation of a polymer film with more homogenous morphology and higher conductivity than the ones prepared from DMAc, DMF, and NMP. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

Spin crossover (SCO) molecules are promising nanoscale magnetic switches due to their ability to modify their spin state under several stimuli. However, SCO systems face several bottlenecks when downscaling into nanoscale spintronic devices: their instability at the nanoscale, their insulating character and the lack of control when positioning nanocrystals in nanodevices. Here we show the encapsulation of robust Fe-based SCO molecules within the 1D cavities of single-walled carbon nanotubes (SWCNT). We find that the SCO mechanism endures encapsulation and positioning of individual heterostructures in nanoscale transistors. The SCO switch in the guest molecules triggers a large conductance bistability through the host SWCNT. Moreover, the SCO transition shifts to higher temperatures and displays hysteresis cycles, and thus memory effect, not present in crystalline samples. Our results demonstrate how encapsulation in SWCNTs provides the backbone for the readout and positioning of SCO molecules into nanodevices, and can also help to tune their magnetic properties at the nanoscale.

Proteins are commonly known to transfer electrons over distances limited to a few nanometers. However, many biological processes require electron transport over far longer distances. For example, soil and sediment bacteria transport electrons, over hundreds of micrometers to even centimeters, via putative filamentous proteins rich in aromatic residues. However, measurements of true protein conductivity have been hampered by artifacts due to large contact resistances between proteins and electrodes. Using individual amyloid protein crystals with atomic-resolution structures as a model system, we perform contact-free measurements of intrinsic electronic conductivity using a four-electrode approach. We find hole transport through micrometer-long stacked tyrosines at physiologically relevant potentials. Notably, the transport rate through tyrosines (105 s-1) is comparable to cytochromes. Our studies therefore show that amyloid proteins can efficiently transport charges, under ordinary thermal conditions, without any need for redox-active metal cofactors, large driving force, or photosensitizers to generate a high oxidation state for charge injection. By measuring conductivity as a function of molecular length, voltage, and temperature, while eliminating the dominant contribution of contact resistances, we show that a multistep hopping mechanism (composed of multiple tunneling steps), not single-step tunneling, explains the measured conductivity. Combined experimental and computational studies reveal that proton-coupled electron transfer confers conductivity; both the energetics of the proton acceptor, a neighboring glutamine, and its proximity to tyrosine influence the hole transport rate through a proton rocking mechanism. Surprisingly, conductivity increases 200-fold upon cooling due to higher availability of the proton acceptor by increased hydrogen bonding.

Conducting polymer hydrogels combine electrical conductivity and tunable water content, rendering them strong candidates for a range of applications including biosensors, cell culture platforms, and energy storage devices. However, these hydrogels are mechanically brittle and prone to damage, prohibiting their use in emerging applications involving dynamic movement and large mechanical deformation. Here, we demonstrate that applying the concept of architecture to conducting polymer hydrogels can circumvent these impediments. A stereolithography 3D printing method is developed to successfully fabricate such hydrogels in complex lattice structures. The resulting hydrogels exhibit elastic compressibility, high fracture strain, enhanced cycling stability, and damage-tolerant properties despite their chemical composition being identical to their brittle, solid counterparts. Furthermore, concentrating the deformation to the 3D geometry, rather than polymer microstructure, effectively decouples the mechanical and electrical properties of the hydrogel lattices from their intrinsic properties associated with their chemical composition. The confluence of these new physical properties for conducting polymer hydrogels opens broad opportunities for a myriad of dynamic applications.

LiBr/H2O as working pair in absorption chiller is widely used in the absorption refrigeration system, and the electrical conductivity is used as secondary properties as an empirical relation with temperature and concentration as a simple method to measure the concentration. In this paper, another working pair Carrol/H2O is chosen, more suitable for air-cooled cycles. Carrol contains ethylene glycol and LiBr with a mass ratio at 4.5:1 and has advantages of low risk of crystallization and reduce the LiBr charge. The working range for the LiBr/H2O solution is temperature 25-80°C, at concentration 50–64%, in term of Carrol/H2O system, the temperature range is 25-80°C, concentration range is 50%-75%. The electrical conductivity will be measured according to the working range and a typical used solution extracted from an absorption chiller prototype will also be measured to compare with the experimental result., The author J.Zheng and Y.Liu both hold a scholarship from China Scholarship Council for PhD at the University of Polytechnique Catalunya., Peer Reviewed, Postprint (published version)

Els models matemàtics detallats juguen un paper fonamental en l'estudi de les malalties cardíaques. En aquest projecte, desenvolupo el primer model matemàtic complet del teixit auricular de porc. Per assolir-ho, faig servir dades experimentals de potencials d'acció (AP) i de restitució, així com mesures experimentals precises dels corrents iònics en aurícules porcines. El model conté una descripció nova per al corrent "transient outward" (transitori cap a fora) que, de manera única en el porc, consisteix únicament en un corrent d'ions de clor (I_Cl,Ca) dirigits per l'activitat de calci. El model és capaç de generar APs fisiològicament precisos per diferents freqüencies d'estimulació i reprodueix correctament restitució (o histèresi) en la duració de l'AP (APD), l'amplitud de l'AP, velocitat de pujada i potencial de repòs amb total acord amb els resultats experimentals. També he ampliat el model a vàries dimensions per simular teixit cardíac extès en l'espai. En dues dimensions (2D), el model pot produir una espiral estable amb un centre hiper-meàndric que, en dominis més grans, es trenca en diverses espirals més petites. Les espirals en 2D mostren una APD i alternants de longitud d'ona plenament consistents amb les prediccions teòriques. A més, testejo un mètode proposat per a l'eliminació d'alternants mitjançant la inhibició de I_Cl,Ca, amb resultats negatius. Una anàlisi de Fourier del sistema revela al menys 4 freqüències fonamentals del sistema. Finalment, concloc la tesi amb una explicació detallada de les limitacions del model i una discussió sobre futures perspectives., Los modelos matemáticos detallados juegan un papel fundamental en el estudio de las enfermedades cardíacas. En este proyecto, desarrollo el primer modelo matemático completo del tejido auricular del cerdo. Para ello, uso datos experimentales de potenciales de acción (AP) y de restitución, así como medidas experimentales precisas de las corrientes iónicas presentes en las aurículas porcinas. El modelo contiene una nueva descripción para la corriente "transient outward" (transitoria hacia fuera) que, de manera única en el cerdo, consiste únicamente en una corriente de iones de cloro (I_Cl,Ca) dirigidos por la actividad de calcio. El modelo es capaz de generar APs fisiológicamente precisos para distintas frecuencias de estimulación y reproduce correctamente restitución (o histéresis) en la duración del AP (APD), amplitud del AP, velocidad de subida y potencial de reposo en total acuerdo con los resultados experimentales. También he ampliado el modelo a varias dimensiones para simular tejido cardíaco extendido en el espacio. En dos dimensiones (2D), el modelo puede producir una espiral estable con un centro hiper-meándrico que, en dominios más grandes, se rompe en varias espirales más pequeñas. Las espirales en 2D muestran una APD y alternantes de longitud de onda plenamente consistentes con las predicciones teóricas. Además, testeo un método propuesto para la eliminación de alternantes mediante la inhibición de I_Cl,Ca, con resultados negativos. Un análisis de Fourier de la trayectoria del centro de la espiral revela al menos 4 frecuencias fundamentales en el sistema. Finalmente, concluyo la tesis con una explicación detallada de las limitaciones del modelo y una discusión sobre futuras perspectivas., Detailed mathematical models play a fundamental role in the study of heart disease. In the present project, I develop the first complete mathematical model of pig atrial tissue. For this, I use experimental data for action potential (AP) characteristics and restitution, as well as precise experimental descriptions of individual ionic currents in pig atria. The model contains a novel description of the transient outward current, given solely by a calcium-driven chloride current (I_Cl,Ca), unique to the pig. The model generates physiologically accurate pig APs at different stimulation frequencies and is able to correctly reproduce restitution (or hysteresis) in AP duration (APD), AP amplitude, upstroke velocity and resting membrane potential in full agreement with experimental results. I have also extended the model to higher dimensions to mimic spatially extended cardiac tissue. In two dimensions (2D), the model could sustain a stable hypermeandering spiral that broke up into smaller spirals in larger simulation domains. The spiral waves in the 2D pig atrial model show APD and wavelength alternans that are consistent with theoretical predictions. I test a method to suppress this alternans by I_Cl,Ca inhibition, with negative results. A Fourier analysis of the trajectory of the spiral tip reveals at least 4 main driving frequencies in the system. Finally, I conclude my thesis with a detailed account of limitations of the model and future perspectives., Outgoing

Aquest projecte exposa el comportament de les descàrregues parcials (DP’s) en els cables de MT i els seus accessoris. S’estudia quin és el procés de formació, l’evolució, la classificació, i les conseqüències de les DP’s. A més, es comparen les metodologies de detecció Online i Offline, enfrontant els seus avantatges i inconvenients; S’explica el fonament de reflectometria, per la qual es pot determinar la posició física de les DP’s, qüestió imprescindible per una eventual acció correctora. Per últim, la part pràctica consisteix en replicar diferents defectes de muntatge sobre accessoris, i avaluar quin és el comportament de les DP’s segons l’anàlisi del seu patró resolt en fase i la seva empremta dactilar (fingerprints), obrint un camí per a la seva caracterització en diferents instal·lacions., Este proyecto expone el comportamiento de las descargas parciales (DP'S) en los cables de MT y sus accesorios. Se estudia cuál es el proceso de formación, la evolución, la clasificación, y las consecuencias de las DP'S. Además, se comparan las metodologías de detección Online y Offline, enfrentando sus ventajas e inconvenientes; Se explica el fundamento de reflectometría, por la que se puede determinar la posición física de las DP's, cuestión imprescindible para una eventual acción correctora. Por último, la parte práctica consiste en replicar diferentes defectos de montaje sobre accesorios, y evaluar cuál es el comportamiento de las DP s según el análisis de su patrón resuelto en fase y su huella dactilar (fingerprints), abriendo un camino para la su caracterización en diferentes instalaciones., This project exposes the behavior of partial discharges (PD's) in MV cables and their accessories. The formation process, evolution, classification and consequences of PD's are studied. In addition, the Online and Offline detection methodologies are compared, facing their advantages and disadvantages; the basis of reflectometry is explained, by which the physical position of PD's can be determined, an essential issue for an eventual corrective action. Finally, the practical part consists of replicating different assembly defects on fixtures, and evaluating the behavior of the PD's according to the analysis of their phase-resolved pattern and fingerprints, opening a way for their characterization in different installations.

Introduction: The salinity of Lake Texcoco is due to the fact that it was an endorheic basin, it had no way of washing the salts. The causes of salinization of agricultural soils in these plots are: poor irrigation management, use of low quality water for irrigation and excessive use of chemical fertilizers. The objective of this work was to analyze the ionic composition and compare the sodium adsorption ratio - explicit and adjusted exchangeable sodium percentage of an agricultural plot. Method: Soil sampling was done to determine the parameters of: pH, electrical conductivity, calcium, magnesium, sodium, potassium, carbonate, bicarbonate, chloride, and sulfate, according to NOM-021-RECNAT-2000. In addition to interpolation maps and contour lines. Results and discussion: According to the results obtained from the laboratory, the plot is made of saline - sodium soil. A significant difference was found between the sodium adsorption ratio (SAR) and the adjusted sodium adsorption ratio, the latter being the highest. The interpolated images and contour lines give an artificial view of the sodium adsorption ratio and the percent exchangeable sodium (ESP). Conclusion: In general, the plot presents high values of SAR and ESP. So, in almost the entire plot there is a risk of sodicity. There are significant differences between SAR and adjusted SAR, but there is no significant difference between ESP and ESP calculated with adjusted SAR. The SAR-EC classification in most cases present soils of very high salinity and medium sodicity (C4-S2)., Resumen Introducción: La salinidad del lago de Texcoco se debe a que éste fue una cuenca endorreica, no tenía forma de lavar las sales. Las causas de salinización de los suelos agrícolas en estas parcelas son: manejo deficiente del riego, uso de aguas de baja calidad para riego y uso excesivo de los fertilizantes químicos. El objetivo de este trabajo fue analizar la composición iónica y comparar la relación de adsorción de sodio-porciento de sodio intercambiable explícita y ajustada de una parcela agrícola. Método: Se hizo un muestreo de suelo para determinar los parámetros de: pH, conductividad eléctrica, calcio, magnesio, sodio, potasio, carbonato, bicarbonato, cloruro y sulfato, de acuerdo con la NOM-021-RECNAT-2000. Además, se realizaron mapas de interpolaciones y curvas de nivel. Resultados y discusión: De acuerdo con los resultados obtenidos del laboratorio, la parcela es de suelo salino-sódico. Se encontró diferencia significativa entre la relación de adsorción de sodio (RAS) y la relación de adsorción de sodio ajustada, siendo este último el más elevado. Las imágenes interpoladas y las curvas de nivel dan una visión artificial de la relación de adsorción de sodio y el porciento de sodio intercambiable (PSI). Conclusión: En general, la parcela presenta valores elevados de RAS y PSI. Por lo que en casi toda la parcela existe riesgo de sodicidad. Existen diferencias significativas entre RAS y RAS ajustado, pero no existe diferencia de importancia entre el PSI y el PSI calculado con RAS ajustado. La clasificación RAS-CE, en la mayoría de los casos, presenta suelos de salinidad muy alta y sodicidad media (C4-S2).

Spin crossover (SCO) molecules are promising nanoscale magnetic switches due to their ability to modify their spin state under several stimuli. However, SCO systems face several bottlenecks when downscaling into nanoscale spintronic devices: their instability at the nanoscale, their insulating character and the lack of control when positioning nanocrystals in nanodevices. Here we show the encapsulation of robust Fe-based SCO molecules within the 1D cavities of single-walled carbon nanotubes (SWCNT). We find that the SCO mechanism endures encapsulation and positioning of individual heterostructures in nanoscale transistors. The SCO switch in the guest molecules triggers a large conductance bistability through the host SWCNT. Moreover, the SCO transition shifts to higher temperatures and displays hysteresis cycles, and thus memory effect, not present in crystalline samples. Our results demonstrate how encapsulation in SWCNTs provides the backbone for the readout and positioning of SCO molecules into nanodevices, and can also help to tune their magnetic properties at the nanoscale.

Spin crossover (SCO) molecules are promising nanoscale magnetic switches due to their ability to modify their spin state under several stimuli. However, SCO systems face several bottlenecks when downscaling into nanoscale spintronic devices: their instability at the nanoscale, their insulating character and the lack of control when positioning nanocrystals in nanodevices. Here we show the encapsulation of robust Fe-based SCO molecules within the 1D cavities of single-walled carbon nanotubes (SWCNT). We find that the SCO mechanism endures encapsulation and positioning of individual heterostructures in nanoscale transistors. The SCO switch in the guest molecules triggers a large conductance bistability through the host SWCNT. Moreover, the SCO transition shifts to higher temperatures and displays hysteresis cycles, and thus memory effect, not present in crystalline samples. Our results demonstrate how encapsulation in SWCNTs provides the backbone for the readout and positioning of SCO molecules into nanodevices, and can also help to tune their magnetic properties at the nanoscale.

Introduction: The salinity of Lake Texcoco is due to the fact that it was an endorheic basin, it had no way of washing the salts. The causes of salinization of agricultural soils in these plots are: poor irrigation management, use of low quality water for irrigation and excessive use of chemical fertilizers. The objective of this work was to analyze the ionic composition and compare the sodium adsorption ratio - explicit and adjusted exchangeable sodium percentage of an agricultural plot. Method: Soil sampling was done to determine the parameters of: pH, electrical conductivity, calcium, magnesium, sodium, potassium, carbonate, bicarbonate, chloride, and sulfate, according to NOM-021-RECNAT-2000. In addition to interpolation maps and contour lines. Results and discussion: According to the results obtained from the laboratory, the plot is made of saline - sodium soil. A significant difference was found between the sodium adsorption ratio (SAR) and the adjusted sodium adsorption ratio, the latter being the highest. The interpolated images and contour lines give an artificial view of the sodium adsorption ratio and the percent exchangeable sodium (ESP). Conclusion: In general, the plot presents high values of SAR and ESP. So, in almost the entire plot there is a risk of sodicity. There are significant differences between SAR and adjusted SAR, but there is no significant difference between ESP and ESP calculated with adjusted SAR. The SAR-EC classification in most cases present soils of very high salinity and medium sodicity (C4-S2)., Resumen Introducción: La salinidad del lago de Texcoco se debe a que éste fue una cuenca endorreica, no tenía forma de lavar las sales. Las causas de salinización de los suelos agrícolas en estas parcelas son: manejo deficiente del riego, uso de aguas de baja calidad para riego y uso excesivo de los fertilizantes químicos. El objetivo de este trabajo fue analizar la composición iónica y comparar la relación de adsorción de sodio-porciento de sodio intercambiable explícita y ajustada de una parcela agrícola. Método: Se hizo un muestreo de suelo para determinar los parámetros de: pH, conductividad eléctrica, calcio, magnesio, sodio, potasio, carbonato, bicarbonato, cloruro y sulfato, de acuerdo con la NOM-021-RECNAT-2000. Además, se realizaron mapas de interpolaciones y curvas de nivel. Resultados y discusión: De acuerdo con los resultados obtenidos del laboratorio, la parcela es de suelo salino-sódico. Se encontró diferencia significativa entre la relación de adsorción de sodio (RAS) y la relación de adsorción de sodio ajustada, siendo este último el más elevado. Las imágenes interpoladas y las curvas de nivel dan una visión artificial de la relación de adsorción de sodio y el porciento de sodio intercambiable (PSI). Conclusión: En general, la parcela presenta valores elevados de RAS y PSI. Por lo que en casi toda la parcela existe riesgo de sodicidad. Existen diferencias significativas entre RAS y RAS ajustado, pero no existe diferencia de importancia entre el PSI y el PSI calculado con RAS ajustado. La clasificación RAS-CE, en la mayoría de los casos, presenta suelos de salinidad muy alta y sodicidad media (C4-S2).

Introduction: The salinity of Lake Texcoco is due to the fact that it was an endorheic basin, it had no way of washing the salts. The causes of salinization of agricultural soils in these plots are: poor irrigation management, use of low quality water for irrigation and excessive use of chemical fertilizers. The objective of this work was to analyze the ionic composition and compare the sodium adsorption ratio - explicit and adjusted exchangeable sodium percentage of an agricultural plot. Method: Soil sampling was done to determine the parameters of: pH, electrical conductivity, calcium, magnesium, sodium, potassium, carbonate, bicarbonate, chloride, and sulfate, according to NOM-021-RECNAT-2000. In addition to interpolation maps and contour lines. Results and discussion: According to the results obtained from the laboratory, the plot is made of saline - sodium soil. A significant difference was found between the sodium adsorption ratio (SAR) and the adjusted sodium adsorption ratio, the latter being the highest. The interpolated images and contour lines give an artificial view of the sodium adsorption ratio and the percent exchangeable sodium (ESP). Conclusion: In general, the plot presents high values of SAR and ESP. So, in almost the entire plot there is a risk of sodicity. There are significant differences between SAR and adjusted SAR, but there is no significant difference between ESP and ESP calculated with adjusted SAR. The SAR-EC classification in most cases present soils of very high salinity and medium sodicity (C4-S2)., Resumen Introducción: La salinidad del lago de Texcoco se debe a que éste fue una cuenca endorreica, no tenía forma de lavar las sales. Las causas de salinización de los suelos agrícolas en estas parcelas son: manejo deficiente del riego, uso de aguas de baja calidad para riego y uso excesivo de los fertilizantes químicos. El objetivo de este trabajo fue analizar la composición iónica y comparar la relación de adsorción de sodio-porciento de sodio intercambiable explícita y ajustada de una parcela agrícola. Método: Se hizo un muestreo de suelo para determinar los parámetros de: pH, conductividad eléctrica, calcio, magnesio, sodio, potasio, carbonato, bicarbonato, cloruro y sulfato, de acuerdo con la NOM-021-RECNAT-2000. Además, se realizaron mapas de interpolaciones y curvas de nivel. Resultados y discusión: De acuerdo con los resultados obtenidos del laboratorio, la parcela es de suelo salino-sódico. Se encontró diferencia significativa entre la relación de adsorción de sodio (RAS) y la relación de adsorción de sodio ajustada, siendo este último el más elevado. Las imágenes interpoladas y las curvas de nivel dan una visión artificial de la relación de adsorción de sodio y el porciento de sodio intercambiable (PSI). Conclusión: En general, la parcela presenta valores elevados de RAS y PSI. Por lo que en casi toda la parcela existe riesgo de sodicidad. Existen diferencias significativas entre RAS y RAS ajustado, pero no existe diferencia de importancia entre el PSI y el PSI calculado con RAS ajustado. La clasificación RAS-CE, en la mayoría de los casos, presenta suelos de salinidad muy alta y sodicidad media (C4-S2).

Propranolol (PRO) is a beta-blocker that is readily detected in surface water and hospital wastewater. This pharmaceutical poses a danger for aquatic animals because it is commonly prescribed for heart diseases and anxiety issues. Advanced oxidation processes are commonly tested for the decomposition of pharmaceuticals because they produce various reactive species at room conditions. A liquid-falling film dielectric barrier discharge (DBD) reactor was used for the treatment of a PRO solution, with no catalysts added. A coaxial construction, accompanied by a peristaltic pump, enables the recirculation of the treated liquid. Ambient air was selected as a feed-gas for nonthermal plasma generation under three levels of power dissipated in plasma. Direct contact of liquid film with plasma in this coaxial reactor enables the efficient transfer of reactive oxygen and nitrogen species generated in plasma to the liquid phase. The degradation rate of PRO, pH value, and conductivity were monitored after every cycle of treatment of PRO solution (100 mg/dm3), and in the presence of scavengers (t-butanol and p-benzoquinone). The PRO concentration was monitored by HPLC-DAD, at 213 nm. As expected, the highest applied power (60 W) contributed to the highest degradation rate (100%). At the same time, in these extreme conditions, pH values dropped from 6 to 2.5 and conductivity increased from 20 µS/cm to almost 1450 µS/cm in the tenth cycle of plasma treatment. Moreover, a high power yielded an excessive decontamination level, but also in the grand production of nitric acid. On the other hand, lower values of power lead to less successful endpoints, over 85% and less than 60% of degraded PRO when 35 W and 15 W were applied, respectively. Accordingly, under these conditions, the total production of ions was less intensive. The maximum conductivity value was less than 500 µS/cm for PRO treated with plasma generated by 35 W of power, and under 130 µS/cm for 15 W. To elude the exact role

Certain applications require a contactless measurement to eliminate the risk of sensorinduced sample contamination. Examples can be found in chemical process control, biotechnology or medical technology. For instance, in critically ill patients requiring renal replacement therapy, continuous in‐line monitoring of blood conductivity as a measure for sodium should be considered. A differential inductive sensing system based on a differential transformer using a specific flow chamber has already proven suitable for this application. However, since the blood in renal replacement therapy is carried in plastic tubing, a direct measurement through the tubing offers a contactless method. Therefore, in this work we present a differential transformer for measuring directly through electrically non‐conductive tubing by winding the tube around the ferrite core of the transformer. Here, the dependence of the winding type and the number of turns of the tubing on the sensitivity has been analyzed by using a mathematical model, simulations and experimental validation. A maximum sensitivity of 364.9 mV/mol/L is measured for radial winding around the core. A longitudinal winding turns out to be less effective with 92.8 mV/mol/L. However, the findings prove the ability to use the differential transformer as a truly contactless sensing system. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

Testing the immunity to conducted radiofrequency disturbances, induced by radio-frequency fields, is fundamental within the electromagnetic compatibility assessment of devices having input and/or output cables. This procedure requires assuring the repeatability and accuracy of the test level applied, that is, the voltage and power of the signal injected into the equipment’s cables when these tests are performed. During a preliminary calibration, different instruments could be employed to measure and adjust the disturbance voltage to the corresponding test level, typically, power meters, test receivers or spectrum analyzers. In this paper it is proposed to use oscilloscopes as measuring device and the calibration method has been adapted accordingly. Results indicate oscilloscopes enable valid and time efficient measurements of the radiofrequency voltage signals involved in the tests according the EN 61000-4-6 standard method, with comparable accuracy at lower costs, while it provides further measurements analysis capability and increased robustness., Peer Reviewed, Postprint (author's final draft)

Composite materials offer numerous advantages in a wide range of applications, including thermoelectrics. Here, semiconductor-metal composites are produced by just blending nanoparticles of a sulfide semiconductor obtained in aqueous solution and at room temperature with a metallic Cu powder. The obtained blend is annealed in a reducing atmosphere and afterward consolidated into dense polycrystalline pellets through spark plasma sintering (SPS). We observe that, during the annealing process, the presence of metallic copper activates a partial reduction of the PbS, resulting in the formation of PbS-Pb- CuxS composites. The presence of metallic lead during the SPS process habilitates the liquid-phase sintering of the composite. Besides, by comparing the transport properties of PbS, the PbS-Pb-CuxS composites, and PbS-CuxS composites obtained by blending PbS and CuxS nanoparticles, we demonstrate that the presence of metallic lead decisively contributes to a strong increase of the charge carrier concentration through spillover of charge carriers enabled by the low work function of lead. The increase in charge carrier concentration translates into much higher electrical conductivities and moderately lower Seebeck coefficients. These properties translate into power factors up to 2.1 mW m-1 K-2 at ambient temperature, well above those of PbS and PbS + CuxS. Additionally, the presence of multiple phases in the final composite results in a notable decrease in the lattice thermal conductivity. Overall, the introduction of metallic copper in the initial blend results in a significant improvement of the thermoelectric performance of PbS, reaching a dimensionless thermoelectric figure of merit ZT = 1.1 at 750 K, which represents about a 400% increase over bare PbS. Besides, an average ZTave = 0.72 in the temperature range 320-773 K is demonstrated., Peer Reviewed, Postprint (author's final draft)