Supercapacitors (SCs) represent an environmentally friendly technology, that can replace batteries or work with them in high power density applications. To support the increasing use of SCs, accurate characterization is required under operating conditions. In addition, validated circuital and software models are needed to identify the SCs behavior in dynamic applications. Along with slower but highly accurate methods, novel quick, traceable, and effective measurement techniques are required to evaluate SCs State of Charge (SoC) and State of Health (SoH) and to promote the uptake of SCs in consumer electronics, energy, transport, aerospace and in many other applications. The MetSuperCap project aims to improve the characterization of SCs by providing an accurate identification of their parameters in the laboratory and under operational conditions.

The electrical contact resistance is a key parameter for optimising both the bipolar plate of the polymer electrolyte membrane fuel cell (PEMFC) and the electrical contact of the power terminal of the stack. The contact resistance is affected by the conductivity, roughness, and hardness of the two contacting surfaces. Here, new, application-specific contact resistance measurement methods are proposed for both the stack power terminal, and the bipolar plate. The proposed methods are compared to methods from references as well as standards, and it is concluded that the uncertainty of the measurements can be reduced by changing the measurement setup, and that the influence of probe resistance on measurement results can be eliminated. Furthermore, the effect of different accelerated durability tests on the contact resistance of the power terminal is examined both on test coupons and on a prototype screw connection with an electroless NiP and an electroplated NiSn coatings. As expected, the NiSn coupons gives lower contact resistance after ageing as compared to the NiP. However, the increase in contact resistance seen on coupons after ageing is not observed on the prototype screw connection.

Proton exchange membrane fuel cells (PEMFCs) are an important alternative to fossil fuels and a complement to batteries for the electrification of vehicles. However, their high cost obstructs commercialization, and the catalyst material, including its synthesis, constitutes one of the major cost components. In this work, Pt-Ni and Pt-Ni-Mo(O) nanoparticles (NPs) of varying composition have been synthesized in a single step by pulse electrodeposition onto a PEMFC's gas diffusion layer. The proposed synthesis route combines NP synthesis and their fixation onto the microporous carbon layer in a single step. Both Pt-Ni and Pt-Ni-Mo(O) catalysts exhibit extremely high mass activities at oxygen reduction reaction (ORR) with very low Pt loadings of around 4 mu g/cm(2) due to the favorable distribution of NPs in contact with the proton exchange membrane. Particle sizes of 40-50 nm and 40-80 nm were obtained for Pt-Ni and Pt-Ni-Mo(O) systems, respectively. The highest ORR mass activities were found for Pt67Ni33 and Pt66Ni32-MoOx NPs. The feasibility of a single-step electrodeposition of Pt-Ni-Mo(O) NPs was successfully demonstrated; however, the ternary NPs are of more amorphous nature in contrast to the crystalline, binary Pt-Ni particles, due to the oxidized state of Mo. Nevertheless, despite their heterogeneous nature, the ternary NPs show homogeneous behavior even on a microscopic scale. (C) 2022 The Author(s). Published by Elsevier Ltd.

Research on fuel cell technology is constantly gaining importance, while global emission requirements are becoming more and more restrictive. For environmentally neutral proton exchange membrane fuel cells (PEMFCs) to become a competitive technology, sustainable infrastructures need to be established. One of the main showstoppers is the utilization of the rare and therefore costly precious metal Pt as the key element in the electrocatalysis of hydrogen and oxygen. A huge amount of research is done on immensely reducing or even replacing Pt for future PEMFC technology. In this research update, the progress on oxygen reduction reaction catalysts in acidic media over the past two years is reviewed, with special attention to their durability.

In the search for alternative and renewable energies that will finally allow abandoning the use of fossil fuels once and for all, hydrogen energy is among the most promising solutions able to fuel any kind of device independent of its size. The energy cycle of hydrogen needs a large infrastructure of highly efficient catalysts used in both electrolysers, which produce hydrogen gas, as well as fuel cells, where the energy stored in the hydrogen bond is converted into electrical current. The conversion of hydrogen works most effectively in acidic media, where the most effective and chemically stable material is platinum. The low abundancy and associated high cost of Pt make it impossible to provide a large-scale infrastructure using the commercial Pt/C catalyst. Alternatives must be found to substantially reduce the amount of Pt used as catalyst material without compromising its sustainability. A facile electrodeposition process from aqueous media allows the one-step synthesis of a Ni-Mo-Pt alloy for use in both hydrogen evolution reaction (HER) and energy conversion systems such as fuel cells. In a previous study, mesoporous Ni-Pt films were synthesised by electrodeposition and thoroughly characterised towards HER, finding that the reaction in 0.5 M H 2 SO 4 was efficient, stable and reproducible. However, some leaching of Ni into the sulfuric acid was observed under open circuit conditions [1,2]. In this study, molybdenum is introduced into the previously investigated Ni-Pt alloy to increase the stability of the material in acidic media. With respect to the electrolyte used for the synthesis of the Ni-Pt alloy, all bath components were kept the same except for the addition of sodium molybdate and citric acid. The latter complexes Mo(VI), thus enabling its co-deposition. Due to a pH-dependent complexation of Mo(VI) by citric acid, the composition of the Ni-Mo-Pt alloy is strongly pH-dependent and can further be fine-tuned to the needs of the specific application by changing the electrodeposition parameters. The Mo contents obtained reach from 10 at% up to 50 at%. Alloys with the highest Mo content, however, trigger phase separation. Using potentiostatic electrodeposition, continuous thin films of Ni-Mo-Pt are obtained on a Cu-coated Si substrate. However, the growth of globular particles is favoured on a hydrophobic substrate, such as a carbon-based gas diffusion layer (GDL) typically found in a fuel cell set-up. Further, using pulse electrodeposition, nanoparticles with a mean diameter down to 10 nm are successfully obtained. For HER in 0.5 M H 2 SO 4 , Ni rich alloys with low Pt contents (between 1 at% and 5 at%) are investigated, while alloys with higher Pt contents can provide sufficient electrochemical stability for oxygen reduction reaction (ORR) in a proton exchange membrane (PEM) fuel cell. The stability of alloys with varying composition is determined by incubation in 0.5 M H 2 SO 4 . Cyclic voltammetry curves in the same media are performed on Ni-Mo-Pt nanoparticles in order to activate the surface and remove any contaminants as a preparation for tests in a PEM fuel cell, and to determine their electrochemically active surface area (ECSA). The electrochemical experiments are supplemented with microstructural analysis by SEM and XRD. Acknowledgement: This work has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 764977. Additional support from the Generalitat de Catalunya (2017-SGR-292) and the Spanish Government (MAT2017-86357-C3-1-R and associated FEDER) is also acknowledged. References: [1] K. Eiler, S. Suriñach, J. Sort, E. Pellicer, Appl. Catal. B , 2020 , 265, 118597 [2] K. Eiler, J. Fornell, C. Navarro-Senent, E. Pellicer, J. Sort, Nanoscale , 2020 , 12, 7749

Two common methods for predicting the energy usage in vehicles through mathematical simulation, the ‘backward’ and the ‘forward’ schemes, are discussed and compared in terms of the longitudinal vehicle behaviour they predict. In the backward scheme, the input driving cycle is initially assumed to be followed perfectly and therefore the vehicle speed is not a dynamic state. In the forward scheme, a driver model controls the vehicle in an attempt to follow the input driving cycle, and the vehicle speed is intrinsically a dynamic state. A theoretical study is made with a simple mathematical vehicle model, where it is shown that the two methods neither predict the same expected energy use nor energy variation. Next, the simulation model that is used for the CO2 rating of heavy-duty trucks in Europe, VECTO, is used as an example of the backward method, and an equivalent implementation in a forward scheme is attempted. Two numerical experiments are made with these models: a detailed study of the longitudinal vehicle behaviour on a reference mission; and a study of the predicted CO2 emissions on a family of stochastically generated missions. The conclusion is that the backward method is easier to use but the forward method has a greater potential to predict realistic behaviour.

We propose a novel statistical description of the physical properties of road transport operations by using stochastic models arranged in a hierarchical structure. The description includes speed signs, stops, speed bumps, curvature, topography, road roughness and ground type, with a road type introduced at the top of the hierarchy to group characteristics that are often connected. Methods are described how to generate data on a form (the operating cycle format) that can be used in dynamic simulations to estimate energy usage and CO2 emissions. To showcase the behaviour of the description, two examples are presented using a modular vehicle model for a heavy-duty truck: a sensitivity study on impacts from changes in the environment, and a comparison study on a real goods transport operation with respect to energy usage. It is found that the stop intensity and topography amplitude have the greatest impact in the sensitivity study (8.3% and 9.5% respectively), and the comparison study implies that the statistical description is capable of capturing properties of the road that are significant for vehicular energy usage. Moreover, it is discussed how the statistical description can be used in a vehicle design process, and how the mean CO2 emissions and its variation can be estimated for a vehicle specification.

With the introduction of fuel cell electric vehicles (FCEV), hydrogen gas produced without fossil fuels Is requiredto reduce the CO2 emissions. At the same time, the production of renewable energy ...

This article presents a proposal for an operating cycle format for describing transport missions of road vehicles, for example a logging truck fetching its cargo. The primary application is in dynamic simulation models for evaluation of energy consumption and other costs of transportation. When applied to product development, the objective is an ensemble of components and functions optimised for specific tasks and environments. When applied to selection of vehicle configuration, the objective is a vehicle specification tailored for its task. The proposal is presented and its four main parts: road, weather, traffic and mission, are thoroughly explained. Furthermore, we implement the proposal in an example of a dynamic forward simulation model. The example model is used for two case studies: a synthetic example of a complex transport mission (a logging truck fetching its cargo) that shows some advanced format features, and an example from a real vehicle log file (cargo transport) that seeks to compare the resulting simulated speed profile to the measured one. The results show that the proposed format works in practice. It can represent complex transport missions and it can be used to reproduce the main features of a logged speed profile even when combined with simple driver and vehicle models.

Nb-Ge-C nanocomposite thin films were deposited by dc magnetron sputtering using three elemental targets. The films consist of substoichiometric NbCx in a nanometer-thick matrix of amorphous C and Ge. Films with no Ge contain grains that are elongated in the growth direction with a (111) preferred crystallographic orientation. With the addition of ∼12 at. % Ge, the grains are more equiaxed and exhibit a more random orientation. At even higher Ge contents, the structure also becomes denser. The porous structure of the low Ge content films result in O uptake from the ambient. With higher C content in the films both the amount of amorphous C and C/Nb-ratio increases. The contact resistance was measured by four-point technique as a function of contact force between 0 and 10 N. The lowest contact resistance (1.7 mΩ) is obtained at 10 N. The resistivity varies between 470 and 1700 μΩ·cm depending on porosity and O content.

Incendiary brush discharges can occur when a large or grounded conductor approaches a charged insulator in the presence of flammable atmosphere. The probability of ignition of these discharges is essential to risk assessment in process industry. It is known that even if the total energy released in the discharge exceeds the minimum ignition energy (MIE), there may not be an ignition [1]. In a companion paper in this conference, we have reported simultaneous measurements of ignition and discharge current waveforms for brush discharges in an ethylene-air mixture in ignition tests based on an IEC standard test method [2]. In this paper we show that the resistance of the electrostatic discharge measurement system can have an effect on the peak discharge current signatures and charge transferred in the brush discharge from an insulating surface. The resistance of the discharge probe seems to affect the peak current value, but also to lesser extent the amount of charge transferred in the discharge.

Textile fibers and yarns of high conductivity, and their integration into wearable textiles for different electronic applications, have become an important research field for many research groups throughout the world. We have produced novel electrically conductive textile yarns by vapor-phase polymerization (VPP) of a conjugated polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), on the surface of commercially available textile yarns (viscose). In this article, we have presented a novel setup for electrical resistance measurements, which can be used not only for fibrous structures but also for woven structures of specific dimensions. We have reported a two-point resistance-measuring method using an already manufactured setup and also a comparison with the conventionally used method (so-called crocodile clip method). We found that the electrical properties of PEDOT-coated viscose fibers strongly depend on the concentration of oxidant (FeCl3) and the doping (oxidation) process of PEDOT. To evaluate the results, we used mass specific resistance values of PEDOT-coated viscose yarns instead of normal surface resistance values. The voltagecurrent (VI) characteristics support the ohmic behavior of coated fibers to some extent. Monitoring of the charging effect of the flow of current through conductive fibers for prolonged periods of time showed that conductivity remains constant. The change in electrical resistance values with increase in the length of coated fibers was also reported. The resistance-measuring setup employed could also be used for continuous measurement of resistance in the production of conductive fibers, as well as for four-point resistance measurement. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Accurate prediction of the probability of ignition arising from charged insulators is a crucial element of risk assessment in process industry. Incendiary brush discharges can occur when a large or grounded conductor approaches a charged insulator in the presence of a flammable atmosphere. This paper describes ignition tests based on an IEC standard method and simultaneously recorded temporal distribution of current released in the discharges, using a discharge probe integrated with the ignition probe. Ignition and non-ignition results are compared with peak discharge current and charge transferred in the discharge. No clear ignition threshold was found for either of these parameters. No major differences were found between igniting and non-igniting waveforms.

In this report we summarise our results from the measurements done at SP Technical Research Institute of Sweden, during spring 2008. The measurements are a part of a Round Robin test within the Euramet organisation. The project is called "EURAMET Project 819 Technical Protocol: Comparisin of Electrical Field Strength Measurements above 1 GHz". The objective with the Round Robin test is to evaluate a transfer probe and to compare its function with conventional techniques for obtaining a specific electric field at a given point.

This paper is a brief review of our recent work and a follow up study on nanocomposite coatings comprising nanocrystalline TiC embedded in an amorphous SiC matrix (nc-TiC/a-SiC) with and without Ag additions applied as electrical contacts. These coating materials are deposited at very high deposition rates (>10 μm/h), to meet industrial demands of high productivity. Here we consider Ti-Si-C-Ag nanocomposite coatings with Ag content in the range of 0-22 at.% deposited in a pilot-plant or an industrial deposition system by dc magnetron sputtering from compound targets onto Si(100) and SiO 2 (100) substrates. The microstructure, electrical, and mechanical properties of the coatings were studied with transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, electrical contact resistance, resistivity, and nanoindentation measurements. Varying the deposition parameters bias and pressure within ranges typical of coating processing had no effect on the structure. A variation was, however, observed for the contact resistance, that was determined to be in the range 400-900 mΩ at a contact force between 1.9-2.65 N. The coatings with highest Ag content had the lowest contact resistance.

The multipath simulator (MPS) is a test environment that can emulate various propagation conditions including Rayleigh fading. It might be used for antenna measurements, drive tests of communication equipment and performance testing of cellular radio equipment. An experimental system has been built to demonstrate basic properties.

The use of Corrugations to Enhance Shielding Effectiveness of Fiber Optic Waweguide Feedthrough

Charge can easily be induced on electronics or on other conducting parts if they are exposed to external electrical fields. In production facilities where sensitive electronics are handled, strong electrostatic fields should be avoided due to the risk of causing electrostatic discharges (ESDs) that could damage components. In electronics manufacturing this is usually achieved by grounding all conductors and removing all insulators from an ESD Protected Area (EPA) in the facility. However, it is not always possible to remove all insulators from the EPA as they are sometimes an essential part of the production processes. In this case, a method of risk assessment is necessary to evaluate safe operation. We have studied induction charging of a dummy PWB (Printed Wiring Board) through a grounded MOSFET transistor, by grounding it directly to metal or through the human body, when the PWB is exposed to a static electric field. The experimental setup can easily be turned into an induction charging probe by changing the MOSFET transistor to a low leakage current, high voltage capacitor of suitable size and measuring the voltage over this capacitor.

Practical assessment of risks for Electrostatic Discharge (ESD) failures of semiconductor devices, due to charges induced on devices in a manufacturing or repair environment of electronics has been difficult, because easily measurable parameters such as the electrostatic field and the potential of a charged surface do not directly quantify the risk. In this paper a new method of assessing the risks with induction charging of a sensitive device is presented by introducing a well-defined dummy device, which is a simple modification of the probe of DC type non-contacting electrostatic voltmeter. By placing the modified potential probe (mimicking large sensitive device) in front of charged surface, risks of ESD failure for a device due to induction charging can be assessed. The electrostatic response of the probe at different distances between charged surface and the probe has been verified by numerical model calculations.

Electrostatic charge is generated by the contact, rubbing together and separation of clothing and car seat upholstery. It is also known that the charging levels will increase in a cold and dry climate. Charge on clothing will induce a separation of charge in the body of the wearer. The net result is an increase in the electrical potential of the body (or body voltage), thereby creating the risk of an electrostatic discharge (ESD) in the form of a spark from the charged human body to a large or earthed conductor. As charge is also bound to the surface of the clothing, brush discharges from the clothing can follow. The effects of sparks from the human body in the environment of a car may be a) to cause uncomfortable and distracting shocks to the person; b) to cause damage or disruption to electronic systems (GPS devices, vehicle management systems, etc); or c) to ignite flammable fuel vapour. A brush discharge from clothing may also ignite fuel vapour and be a risk for (unprotected) sensitive electronic devices (ESDS). The characteristic shape of the discharge current in a brush discharge is very similar to a Human Body Model (HBM) discharge. Measurement systems for determining body voltage and recording brush discharges are described. Results are presented of tests conducted with various combinations of car seat upholstery and clothing in different test environments. The antistatic property of some automotive textiles including conductive threads is emphasized.