Entire Lifetime Research Articles

Prospects of Improving Efficiency and Stability of Hybrid Perovskite Solar Cells by Alumina Ultrathin Films.

Over the last few years, the influence of low temperature (≤80 °C) and, in particular, of room temperature, atomic layer deposited alumina (ALD-Al2O3) on the properties of the underlying hybrid perovskites of different compositions and on the efficiency and stability of the corresponding perovskite solar cells (PSCs) is extensively investigated. The main conclusion is that most probably thanks to the presence of intrinsic defect states in the ALD-Al2O3 and in the perovskite layers, charge transfer and neutralization are possible and the entire lifetime of the PSCs is thus improved. Moreover, the migration of mobile ions between the layers is blocked by the ALD-Al2O3 layer and thus the occurrence of hysteresis in the current density-voltage characteristics of the PSCs is suppressed. Considering the uniform and nondestructive surface coverage, low thermal budget, small amount of material required, and short duration of the established ALD-Al2O3 deposition on top of hybrid perovskites, this additional, but fully solar cell technology-compatible, process step is most likely the most effective, cheapest, and fastest way to improve the efficiency and long-term stability of PSCs and thus increase their marketability.

Corrosion level estimation in reinforced concrete beams by acoustic emission sensing and selective crack measurements

AbstractAccurate corrosion assessment plays an important role in ensuring structural safety of reinforced concrete (RC) structures. However, on‐site assessment of existing concrete structures presents many challenges, including high costs, limited inspection timeframes, and difficult accessibility. To facilitate inspection‐based corrosion assessment, this paper presents a novel approach by combining short‐term acoustic emission (AE) monitoring with selective crack width measurements for corrosion level (CL) assessment. AE sensing is a monitoring technique which can detect ongoing internal degradation mechanisms by analyzing ultrasonic waves emitted by the damage process. Yet, two major challenges arise on site: (1) practical limitations prevent continuous AE monitoring over the structure's entire lifetime and (2) AE can only generate relative results in the absence of reference measurements. This paper addresses both challenges to bridge the gap between laboratory experiments and on‐site monitoring of corroding RC structures. First, short periods of AE monitoring data are analyzed to investigate the potential of AE sensing over limited timeframes. Second, AE data of corroding RC beams are combined with sparse crack width measurements in order to obtain absolute CLs. The proposed methodology is experimentally validated by corroding eight beams with varying dimensions, corrosion zones, and reinforcement layouts. The experimental results prove that the estimated CLs closely match the rebar mass losses, with a mean absolute error of 1.53% CL for beams reaching up to 14% CL, confirming the potential of the combined AE and crack width measurement technique as an efficient and accurate condition assessment approach. Moreover, AE sensing provides detailed spatial variability of the rebar corrosion in the monitored zone, which is challenging to obtain with conventional techniques. By using this dual‐technique approach, shorter monitoring periods prove nearly as effective as continuous AE monitoring in accurately estimating CLs.

Impacts of the replacement of distressed pavements by low noise pavements - a case study in Portugal

BRISA is employing efforts to evaluate the pavement influence as a factor of source noise reduction, while studying forms of adjusting the applicability of the CNOSSOS noise prediction method to the reality of the concession road network, in order to comply with European directives about Environmental Noise evaluation and management. This Project evaluates the environmental noise effects of replacing a wearing course of Porous and Betuminous Asphalt at end-of-life for a course of SMA12 and new Betuminous Asphalt. Two methodologies were applied to evaluate Tire-Pavement noise, (i) through Statistical Pass-By and (ii) Close Proximity methods. Using these methodologies, it was possible to evaluate the effect of the intervention and the evolution of the noise in the first few months of the exploration of the layers and to monitor noise performance of the pavements during its entire lifetime. Brisa is challenged to have better pavements knowledge to extend CNOSSOS pavement library and update noise models.

Energy Yield Modeling of Perovskite–Silicon Tandem Photovoltaics: Degradation and Total Lifetime Energy Yield

This study investigates the impact of degradation in perovskite‐silicon tandem solar cells by means of energy yield (EY) modelling over the entire lifetime. First, we assess the impact on EY of degradation in the individual solar cell parameters of the perovskite top cell. Our analysis reveals that degradation in fill factor, due to a decline in perovskite top cell shunt resistance (RSh), has the most severe impact on the EY, emphasizing the imperative to rectify perovskite imperfections in thin film processing causing RSh decline. Second, we investigate implications of degradation in the perovskite top cell on the EY of current mismatched tandem solar cells. Third, we examine critical thresholds for the “acceptable degradation levels” in the perovskite top cell with regard to degradation in each solar cell parameter, assuming that the total loss in EY must be comparable to the degradation in state‐of‐the‐art silicon. Overall, our study highlights that degradation of the perovskite top cell needs to be assessed with care when extrapolating the impact on the lifetime EY of perovskite‐silicon tandem solar cells. The severity of degradation for different degradation mechanisms in a single junction perovskite solar cell cannot be translated one‐to‐one to tandem devices.

Reactor power control system design and dynamic simulation for load maneuvers over full range and entire lifetime of an integrated supercritical CO2 reactor plant

Due to advantage of high efficiency, low carbon, and flexible operation, the integrated supercritical CO2 reactor plant has promising prospect in energy supply. This paper aims to clarify performance of the reactor plant and establish a reactor power control strategy through numerical modeling. Firstly, performance on separated components is evaluated to provide guidance for control strategy development. Secondly, influence of control methods, controller schemes, and saturation models on control strategy are discussed. Thirdly, dynamic response of reactor plant with proposed control strategy is confirmed via load change transients. Results show that passive control method is infeasible at EOL and load demand below 50 %FP, and active control method must be considered. The proposed control strategy adopts coupled temperature-channel and power-channel scheme and soft saturation model. It ensures safe operation of the plant over full load range in whole lifetime. These results can provide helpful guidance on part-load operation for this system.

Twenty-five years of the Journal of Risk Research: a bibliometric overview

The Journal of Risk Research is a leading international journal in risk research connected to multidisciplinary areas. It was launched in 1998 and founded by Ragnar E. Löfstedt. Motivated by its 25th anniversary in 2023, this paper presents a general bibliometric overview of the leading trends occurring in the journal between 1998 and 2023. The study aims to identify the journal’s impact, the most productive and influential authors, institutions, countries/territories, leading topics, and to analyse their evolution through time. The work mainly uses the Scopus database to analyse the bibliometric data. But in some particular cases, the Web of Science Core Collection database is also used to supplement bibliographic information. Moreover, we develop a graphical mapping of the bibliographic material by applying the Visualisation of Similarities (VOS) viewer software to provide deeper analyses. The graphical visualisation uses co-citation, bibliographic coupling, and co-occurrence of author keywords. The results emphasise the significant growth and impact of the journal throughout its entire lifetime. It is expected that the journal will continue growing its international diversity and disseminating knowledge in risk research all over the world.

Distributed fiber optic strain sensing for structural health monitoring of 70 MPa hydrogen vessels

We report on the development and testing of 70 MPa hydrogen pressure vessels with integrated fiber optic sensing fibers for the automotive use. The paper deals with the condition monitoring of such composite pressure vessels using the optical backscatter reflectometry (OBR) which was applied for a distributed fiber optic strain sensing along fully integrated polyimide-coated single-mode glass optical fiber (SM-GOF). The sensing fibers were embedded into the vessel structure by wrapping them over the inside polymer liner during the manufacturing process of the outside carbon fiber reinforced polymer (CFRP). Detecting local strain events by the integrated fiber optic sensors might be an opportunity for monitoring the material degradation. Regarding the investigation of the ageing behavior, both ambient hydraulic cycling tests and slow burst tests were conducted on 70 MPa pressure vessels with embedded fiber optic sensors. The achieved results contribute to the knowledge about material fatigue to guarantee the safe usage during the entire lifetime of the composite hydrogen storage vessels. The presented work stands in context of the European Horizon 2020 research project SH2APED focused on the development of an innovative hydrogen storage system composed of an assembly of nine 70 MPa tubular pressure vessels used as an automotive battery pack.

Climate and salinity together control above ground carbon accumulation in the Sundarbans mangrove ecosystem

Mangroves play a crucial role in mitigating climate change through carbon (C) accumulation. Developing robust methods for the estimation of long-term C accumulation is essential for monitoring and reporting carbon financing projects under different global mechanisms. Moreover, understanding the effects of climate and habitat on C accumulation is important for developing mangrove management plans and conservation options. In this study, long-term above ground C accumulation in the three most dominated mangrove tree species, Heritiera fomes, Excoecaria agallocha and Sonneratia apetala, was estimated using a dendrochronological approach in two contrasting (low vs high) salinity zones in the Bangladesh Sundarbans. In addition, how climate and habitat (e.g., regulators and soil resources) influence C accumulation was analyzed. For the first time, we estimated C accumulation in mangrove species over their entire lifetime using stem disc-derived tree-ring data. The C accumulation patterns exhibited similar patterns of variation, increasing from pith to bark in each case. C accumulation was significantly higher in the low salinity zone (LSZ) than in the high salinity zone (HSZ) (p < 0.05). The cumulative C accumulation increased with tree age in each case, and C accumulation was influenced mainly by seasonal precipitation, especially during monsoon. General additive modeling (GAM) revealed that soil salinity had a stronger effect on C accumulation variability in the studied tree species. Other regulatory variables (i.e., siltation and elevation) and soil resources (i.e., P and K) had species-specific influences on C accumulation. Tree-ring data show the potential to yield better biomass and C estimations, which could aid frequent and rapid reporting of C accumulation in mangroves. Moreover, the results also suggest that climate and regulatory variables, especially soil salinity, together impact the C cycles in the Sundarbans.

Unpaid work, paid work and gender inequality: An analysis of time transfer accounts for Turkey

AbstractThis paper provides a comprehensive assessment of the total (market and non-market) gender-based production and consumption activities of Turkish men and women at different stages of their life-cycle. Turkey, one of the few emerging economies within the OECD, offers an interesting case-study as its female labour force participation rate is one of the lowest among OECD countries. Our results show that time spent by Turkish women on household activities is, on average, 30 h a week, basically three times as much as men. In fact, the women-to-men time use ratio for unpaid work is roughly twice as much as the OECD average. We estimate that the monetary value of women unpaid household production exceeds 29% of GDP, while the corresponding estimate for men is around 8%. Using the concept of life-cycle deficit, we also show that Turkish men are dependent on housework undertaken by women over their entire lifetime, which is an almost unique feature in comparison to the European and OECD countries. Finally, unlike other OECD countries that have introduced disincentives to early retirement, Turkish men continue to retire early but retain their acquired habits of not sharing the burden of household work.

Energy flux variations and safety assessment of offshore wind and wave resources during typhoons in the northern South China Sea

Extreme ocean conditions during typhoons pose significant challenges to the sustainable utilization of ocean renewable energy. This study focuses on analyzing the wind and sea states within typhoon systems and the variations in offshore wind & wave energy flux during typhoons passing over the northern South China Sea (SCS) from 2000 to 2022. The trajectories and intensities of 769 typhoons in the Western Pacific, along with wind & wave energy flux variations during 155 instances of typhoons making landfall in the SCS, are isolated for comprehensive analysis. Specifically, the safety of energy exploitation during severe typhoon Hato (2017) is assessed considering the local met-ocean condition during typhoon passing and the survival ocean conditions of Offshore Wind Turbines (OWTs) and Wave Energy Converters (WECs). The WRF model and FVCOM-SWAVE model are used to provide necessary winds and waves during the passage of Hato with simulations validated against observations for reliable safety assessments. The results show that, over the past 22 years, the regions spanning from northern Guangdong to the Luzon Strait have been subjected to robust winds and formidable waves. The average values of Wind Power Density (WPD) and Wave Power Flux (WPF) during typhoons have exceeded 1500 W/m2 and 20 kW/m, respectively. In the Hato typhoon system, the maximum wind speed surpasses 60 m/s, while the significant wave height is about 10 m. Moreover, the survival capabilities of current OWTs (MySE5.5-155, SWT-6.0-154, SWT-7.0-154, SG 8.0–167 DD and D10000-185) and WECs (Sea Power and CycWEC) are assessed, demonstrating their ability to withstand the entire typhoon lifetime. Therefore, OWTs and WECs exhibit robust survival capabilities through comprehensive assessments based on the validated numerical simulation results, facing extreme typhoon conditions.

현대 비극의 ‘사라지는 하마르티아’와 ‘투쟁의 운명’

This paper analyzes the specific characteristics of classical tragedies and the essence of tragedy in modern drama, mainly focusing on John Millington Synge’s Riders to the Sea. Arthur Miller defined the possibility of modern tragedy as the tragic experience of the common man in relationship to the environment. However, in the modern era, the environment is often represented or segmented by capitalism, leading to the misconception that modern tragedy may be succinctly defined by the struggles of ordinary people facing continuous situational hardships in pursuit of their dreams. In contrast, Synge’s tragic drama Riders to the Sea (first performed in 1904), which this paper observes, is grounded in an isolated natural setting while still remaining connected with the realm of the divine or the universe. Focusing on the phase of vanishing hamartia, the escape from guilt of the subjects, and the expansion of the concept of necessity from outer to their inner sphere, this paper argues how classic tragic essence is also manifested in modern plays, provoking profound thoughts among the audience and elevating their souls through elegant suffering and intellectual clarification in its own way. In its characteristic of stillness, where the conclusion is drawn out over an entire lifetime of struggle and disguised to obscure emotional suffering beneath a veneer of pessimism or idealism, the modern tragic drama establishes its own tragic genre with catharsis and magnitude. This contributes to a deeper level of meaningful understanding in the lives of all ordinary people in the contemporary world.

Bridging satellite missions: deep transfer learning for enhanced tropical cyclone intensity estimation

ABSTRACT Geostationary satellites are valuable tools for monitoring the entire lifetime of tropical cyclones (TCs). Although the most widely used method for TC intensity estimation is manual, several automatic methods, particularly artificial intelligence (AI)-based algorithms, have been proposed and have achieved significant performance. However, AI-based techniques often require large amounts of input data, making it challenging to adopt newly introduced data such as those from recently launched satellites. This study proposed a transfer-learning-based TC intensity estimation method to combine different source data. The pre-trained model was built using the Swin Transformer (Swin-T) model, utilizing data from the Communication Ocean and Meteorological Satellite Meteorological Imager sensor, which has been in operation for an extensive period (2011–2021) and provides a large dataset. Subsequently, a transfer learning model was developed by fine-tuning the pre-trained model using the GEO-KOMPSAT-2A Advanced Meteorological Imager, which has been operational since 2019. The transfer learning approach was tested in three different ways depending on the fine-tuning ratio, with the optimal performance achieved when all layers were fine-tuned. The pre-trained model employed TC observations from 2011 to 2017 for training and 2018 for testing, whereas the transfer learning model utilized data from 2019 and 2020 for training and 2021 for testing to evaluate the model performance. The best pre-trained and transfer learning models achieved mean absolute error of 6.46 kts and 6.48 kts, respectively. Our proposed model showed a 7–52% improvement compared to the control models without transfer learning. This implies that the transfer learning approach for TC intensity estimation using different satellite observations is significant. Moreover, by employing a deep learning model visualization approach known as Eigen-class activation map, the spatial characteristics of the developed model were validated according to the intensity levels. This analysis revealed features corresponding to the Dvorak technique, demonstrating the interpretability of the Swin-T-based TC intensity estimation algorithm. This study successfully demonstrated the effectiveness of transfer learning in developing a deep learning-based TC intensity estimation model for newly acquired data.

Characterization of accelerated hydrolysis degradation of poly (lactic acid) in phosphate buffered saline solution

For the reliable use of polylactic acid (PLA) materials in the human body for supportive implants, an appropriate accelerated testing method to assess the lifetime of the PLA with an acceptable model that can describe the entire degradation process is required. In this study, accelerated degradation were conducted on the polylactic acid (PLA) exposed to the phosphate buffered saline (PBS) solution at elevated temperatures, 50 ℃, 60 ℃, and 70 ℃. The high level of accelerated degradation was achieved with elevating temperatures. The evolution of surface degradation degree with exposure time was quantified by measuring the molecular end group and modeled by a proper equation. In addition, it was demonstrated that hydrolysis-induced chain-scission is the governing mechanism in the accelerated degradation. The chemi-crystallization behavior with the hydrolysis degradation was also characterized. The morphological observation revealed that the microcracks and pits are pronouncing mechanisms of surface damage. The tensile properties were severely degraded after a certain period of induction time, depending on the temperature. The sorption kinetics were also assessed and explained during the entire lifetime until the severe mass loss, based on the diffusion with degradation behavior, as well as the evolution of the morphological damages. The formation of the surface degradation layer and subsequent damages are suspected to result in early saturation and secondary sorption behavior at the elevated temperature. Finally, the integrated correlations between the sorption behavior, amount of hydrolysis degradation, and mechanical property decrease were physically described, and accurate correspondences were obtained.

Connections between different characteristics of the Tibetan Plateau vortices

AbstractTibetan Plateau vortices (TPVs) are major rainfall triggers over the Tibetan Plateau (TP), which often cause heavy rainfalls in eastern China when moving off the TP. Although previous studies have revealed the climatic characteristics of TPVs at different timescales, the relationships between the different activity characteristics of TPVs are unclear. In this study, TPVs during May to August during 1998–2020 are objectively identified based on ERA5 reanalysis data, and connections between the initial states of TPVs and their subsequent activities, as well as the connections between the states of TPVs before moving off the TP and those after moving off are investigated. It is reported that the TPVs generated over the central and western TP north of 32° N, particularly near 84° E, 35° N, are always stronger, maintain longer and move further in their subsequent life, and the TPVs generated near 95° E over the eastern TP move eastwards the fastest. The initial intensity of most TPVs is smaller than 1.1 × 10−4 s−1; regarding these TPVs, their average duration, movement distance and movement speed exhibit an initial decrease followed by an increase as the initial intensity rises. The stronger the TPVs initially are, the stronger they are in their entire lifetime. The majority of the moving‐off TPVs are generated over the eastern TP; generally, TPVs generated further east with a large initial intensity are more likely to move off the TP. After moving off the TP, most TPVs remain in the same movement direction as before; if the TPVs are strong when they are over the TP, they tend to be strong, last long and move eastwards further after moving off the TP, and vice versa.

Mating and oviposition of a breeding strain of black soldier fly Hermetia illucens (Diptera: Stratiomyidae): polygynandry and multiple egg-laying

Abstract Black soldier fly (BSF), Hermetia illucens, is a promising species to valorise organic wastes and agricultural co-products into nutrient-rich animal feed. Thus, basic knowledge of its reproductive behaviour is needed to optimize its rearing processes and future selection. In this study, we investigated the reproductive behaviour (mating and egg-laying) of a mass-breeding BSF strain to (1) determine whether their females were monandrous or polyandrous, (2) describe the impact of multiple mating on egg production and fertility, and (3) describe where and when caged individuals mate and lay eggs. Newly emerged adults were individually tagged with acrylic paint to monitor their mating and egg-laying behaviour during their entire lifetime. Our results indicate that adults mated on average three times before dying, with different or even former partners. Some of them mated up to nine times. We also provide the first observation of multiple egg-laying for domesticated H. illucens females and show that virgin females can lay unfertilized eggs, in smaller quantities compared to mated ones. Finally, this study provides the first evidences that H. illucens can be polygynandrous and that multi-mated females can lay eggs several times, thus increasing egg production, in mass breeding conditions.

Novel adaptive DCOPA using dynamic weighting for vector of performances indicators optimization of IoT networks

Clustering in the Internet of Things (IoT) involves organizing devices into groups to streamline network management and optimize resource utilization, including Internet connections, energy usage, coverage, quality of service, and connectivity. DCOPA (A Distributed Clustering Based on Objects Performances Aggregation for Hierarchical Communications in IoT Applications) is a recent distributed clustering protocol based on a timer for cluster formation where the election of Cluster Heads (CHs) is modeled as a multicriteria problem. In this paper, three contributions are presented. Firstly, the DCOPA protocol is analyzed with a focus on its multi-criteria aggregation function T(i) which directly contributes to the election of the CHs and the formation of the network’s clusters. This is then followed by an in-depth analysis of the impact and the variation of the weights assigned to the two aggregated criteria which are the energy and the distance from the base station. A verification of the scalability, load balancing and distribution of the clusters and CHs will follow. Secondly, a new formal notation for the performance analysis, specifically focusing on the mortality and lifetime based on the Vector of Performance Indicators (VPI), will be introduced for IoT. As a third contribution, a revised version of DCOPA is introduced called ADCOPA (Adaptive DCOPA Using Dynamic Weighting for Vector of Performances Indicators Optimization of IoT Networks). ADCOPA is based on a new property which is the dynamicity or the variability of the weights of the criteria used in the election function of CHs. The simulation results show that the ADCOPA algorithm, which dynamically adjusts the weights of the criteria during the network’s lifetime, outperforms the DCOPA algorithm. The latter uses static weights for the criteria that remain unchanged for the entire lifetime of the network. This confirms that the ability to dynamically adjust the weighting of the criteria is an important factor in achieving better performance.

Life cycle cost modelling using 6D BIM in construction: A comparative study

Life Cycle Costing (LCC) and Building Information Modelling (BIM) are among the important current trends in the construction industry. LCC contributes to the objective management and measurement of costs during the entire lifetime of a building and BIM represents one of the digitalization efforts related to the Construction 4.0 initiative. Because life cycle cost modelling using 6D BIM has the potential to bring significant positive effects such as cost savings and reduced environmental burden, this paper aims to study the development of this concept in the Czech Republic and Austria. The legislative environment, the actual usage of LCC and BIM in practice, as well as problems faced by the Czech and Austrian construction industries, are discussed in this comparative study. The results show that the practical level of use is still relatively low in both countries, yet specific differences were identified, for example those related to the definition of legislative requirements and the availability of standards and specifications.

Aging-Sensitive Fast-Charging for Heavy-Duty Electric Vehicles

To use lithium-ion cells on-board electric vehicles (EVs) safely and efficiently, a battery management system (BMS) is essential. It monitors the battery’s states and controls utilization by limiting e.g., current and temperature. Advanced BMS increasingly use electrochemical models to assess internal states of battery cells and apply usage constraints based on these [1]. The performance of an electrochemical BMS is closely tied to the performance of the underlying model and the accuracy of its parameters [2]. We employ a novel re-parametrization method to update electrochemically constrained optimal fast-charging procedure to minimize battery degradation. The parameters of electrochemical models are typically identified through a combination of physico-chemical characterization techniques and curve fitting [3]. Since model parameters change with aging [4], there is a need to re-parametrize electrochemical models on-board to conserve model accuracy. As basis for this re-parametrization, we propose a novel reference performance test that can be incorporated into a conventional over-night charge and performed intermittently.Optimal control has previously been demonstrated for fast-charging in EV applications [1]. However, electrochemical, and mechanical degradation need to be considered to allow optimal fast charging throughout batteries’ lifetimes. Khalik et al. [5] demonstrated how a charging procedure could be designed a-priori for the entire cycle life, considering a direct implementation of the solid-electrolyte-interphase growth and capacity fade due to the associated lithium consumption. Such approaches can extend battery lifetime, but neither yield optimal charging-procedures at every state-of-health nor handle unknown aging modes on the fly. Our proposed approach involves intermittent identification of electrochemical model parameters and subsequent update of the fast-charging protocol such that it adheres to electrochemical constraints throughout the entire battery lifetime.In this work, summarized in Figure 1, we present this methodology and show results from an experimental study testing the proposed approach vs. conventional charging procedures. The experimental study is performed on state-of-the art automotive cells used in heavy-duty electric vehicles.Figure caption: Comparison of a conventional electrochemically constrained fast-charging procedure with the aging-sensitive approach proposed in the present work.

Economic viability of Li-ion batteries based on the price arbitrage in the European day-ahead markets

The accelerating increase in the power capacity of intermittent renewable energy sources has a significant impact on the operation of power systems. First, it causes a growth in electricity price volatility in energy markets. Second, it requires balancing the system to meet the demand also in windless hours at night. Li-ion batteries, as a promising energy storage technology, are considered a response to the abovementioned challenges. However, their use must generate profits to encourage potential investors. With this in mind, the objective of this paper is to examine the economic profitability of Li-ion batteries based on price arbitrage in the European day-ahead market. For this purpose, 7 years of data from 22 European markets are analysed. These data are multiplied to maintain the volatility of electricity prices within the entire lifetime of the energy storage system. The results provide for each country (i) sets of hours of electricity purchase and sale that corresponds to hours of storage charging and discharging, (ii) a number of charging/discharging cycles, (iii) potential profits of transactions in day-ahead markets, and (iv) net present values of investments for current and projected costs. The study contributes to the existing literature by pointing out the most competitive markets for Li-ion batteries, depending on economic results, market size and renewable generation in power systems. The results of NPV are below zero in each case analysed when the current capital cost is considered. However, a reduction of capital costs increases the profitability of the system, indicating Finnish and Romanian markets as the most competitive for Li-ion batteries.

Combined Ash and Soot Monitoring for Gasoline Particulate Filters Using a Radio-Frequency-Based Sensor

Increasingly stringent emission limits have made particulate filters necessary for gasoline engines. Similar to diesel applications, gasoline particulate filters (GPFs) can be monitored by differential pressure measurement or by the radio-frequency-based filter diagnosis (RF sensor). In addition to measuring the soot loading, ash detection is critical for monitoring the GPF over the entire vehicle lifetime. Because the RF sensor detects the filter loading through a change in the dielectric properties of the GPF, it can detect not only soot but also ash. In diesel applications, the RF sensor has already demonstrated its potential for ash detection. To verify the feasibility of simultaneous ash and soot monitoring for GPFs, filters were loaded with ash on an engine test bench and measured on a lab test bench under defined synthetic exhaust gas conditions. By evaluating resonant modes, soot and ash could be clearly distinguished, as ash mainly affects the resonant frequency, while soot also changes the quality factor due to its high dielectric losses. However, higher soot loadings could not be detected by the resonant parameters, but instead by a frequency-averaged transmission signal. While the presence of ash caused an offset in this signal, its sensitivity to soot was not affected. Thus, the influence of ash can be corrected if the signal in the soot-free filter state is known, e.g., from the behavior of the resonant parameters. Therefore, even with a continuously increasing ash loading over the lifetime of a vehicle, an accurate soot detection is possible with the RF sensor.