Switch Failure Research Articles

Switching Vedolizumab from IV to SC Injection in Inflammatory Bowel Disease Patients with Active Disease: Real-World Experience from a German IBD Cohort.

Vedolizumab (VDZ) for subcutaneous (SC) injection was approved for use in Europe in 2020 and the US in 2023. Promising efficacy and tolerability have been proven in pivotal trials. However, real-world data on the SC use of VDZ, especially in patients with active disease, are still lacking. We aimed to determine treatment persistence and the drug's efficacy in inflammatory bowel disease (IBD) patients with active disease in comparison to patients in clinical remission. Patients treated for IBD in a tertiary care center from July 2020 to December 2021 were included in this study. Clinical and biochemical parameters and data on treatment adherence were collected. VDZ trough levels and disease activity before and after the switch from intravenous (IV) to SC injections were monitored during routine checkups and were retrospectively analyzed. The patients were followed up until week 20. Eighty-two patients were included in the study. Of them, 35 patients had active disease (35/82 = 43%) at the time of the switch and 47 patients (47/82 = 57%) were in remission. In total, 10 patients experienced switch failure, 5 were switched back to IV VDZ, and 5 were swapped to a different biologic agent. We observed an increase in VDZ trough levels from the switch to week 8 and from the switch to week 20 in the remission group. Vedolizumab trough levels of 7.4, 51.4, and 33.45 ug/mL at the switch, week 8, and week 20 were identified to discriminate between remission and disease activity in our cohort. There was no new safety signal detected during the study period. The switch from IV to SC VDZ proved to be efficient, safe, and even capable of reducing residual disease activity.

Cellular Energy Metabolism is Altered in the Trem2R47h NSS Mouse Model of AD

AbstractBackgroundHuman GWAS have identified variants of the triggering receptor expressed on myeloid cells 2 (TREM2) gene as a major genetic risk factor for Alzheimer’s disease (AD). TREM2 is necessary for maintaining microglial metabolic fitness and may be critical for providing cellular energy demands for microglial‐dependent β amyloid phagocytosis. Here, we examine the plasma metabolome of Trem2 R47H NSS mice in the presence of β amyloid plaques to examine alterations of cellular energy metabolites.MethodWe examined the abundance of plasma metabolites obtained from homozygous Trem2 R47H NSS (Jax #034036), 5xFAD x Trem2 R47H NSS, 5xFAD hemizygous, and control (WT) mice (n = 10 each group) at 4 months of age. We measured 762 lipids and 204 polar metabolites from peripheral plasma using liquid chromatography mass spectrometry (LC‐MS). We conducted differential abundance (DA) analysis for the individual metabolites and compared the groups using FDR correction (q < 0.05). We used DA metabolites in pathway analysis to examine which metabolic pathways were impacted by TREM2 R47H and the presence of amyloid (5xFAD hemizygous background).ResultHomozygous Trem2 R47H NSS mice, both in the presence and absence of amyloid plaques (i.e. 5xFAD hemizygous or non‐transgenic background), had significantly lower abundance α‐D‐glucose and lactate compared to their relevant control groups (q’s < 0.05). 5xFAD x Trem2 R47H NSS mice also showed significantly lower phosphatidylethanolamine (PE) abundance relative to 5xFAD hemizygous mice (q’s < 0.05) and this was especially apparent for female mice (q’s < 0.05). KEGG pathway analysis using DA features revealed enrichment on Glycerophospholipid Metabolism and Glycolysis/Gluconeogenesis pathways.ConclusionWe report lower levels of the entry substrate to glycolysis (Glucose) and an end product metabolite (Lactate) in homozygous Trem2 R47H NSS mice, especially in the presence of amyloid. The depletion of these energy metabolites in circulating blood may reflect failure of the immunometabolic switch from oxidative phosphorylation to glycolysis in support of increased energy demands of activated microglia. We also find significant depletion of glycerophospholipids in Trem2 R47H NSS mice, which was more pronounced for female mice. These results suggest cellular energy dyshomeostasis associated with microglial activation which can be measured in peripheral blood.

Analysis of Blocking Capability Failure Mechanism in IGBT Module Under High Salt Spray Environment

High salt spray environment is a threat to the long-term stability and the robustness of an insulated gate bipolar transistor (IGBT) module. Failure mechanisms of IGBTs have been discussed in normal and high humidity environment, which in high salt spray environment is unclear and seldom reported. In this paper, experiments in high salt spray environment are conducted on wire-bonding IGBT modules to reveal failure mechanism. Different degradations of the blocking capability are observed for the same packaged IGBTs in the salt spray environment. Based on experiment results, degradation substances in the internal package are analyzed by means of scanning electron microscope (SEM) and X-ray diffraction (XRD) to reveal the key composition affecting the blocking capability of IGBT switches. Finally, a failure model is used to reveal the mechanism that the insulation strength of the terminal area in the chip edge is reduced by substances, resulting in the blocking failure of IGBT switches. The analysis of IGBT module failure mechanism is of great significance to reliability evaluation and optimal design for package structures of power modules applied in harsh environments.

A novel multi-resolution network for the open-circuit faults diagnosis of automatic ramming drive system

The open-circuit fault is one of the most common faults of the automatic ramming drive system (ARDS), and it can be categorized into the open-phase faults of Permanent Magnet Synchronous Motor (PMSM) and the open-circuit faults of Voltage Source Inverter (VSI). The stator current serves as a common indicator for detecting open-circuit faults. Due to the identical changes of the stator current between the open-phase faults in the PMSM and failures of double switches within the same leg of the VSI, this paper utilizes the zero-sequence voltage component as an additional diagnostic criterion to differentiate them. Considering the variable conditions and substantial noise of the ARDS, a novel Multi-resolution Network (MrNet) is proposed, which can extract multi-resolution perceptual information and enhance robustness to the noise. Meanwhile, a feature weighted layer is introduced to allocate higher weights to characteristics situated near the feature frequency. Both simulation and experiment results validate that the proposed fault diagnosis method can diagnose 25 types of open-circuit faults and achieve more than 98.28% diagnostic accuracy. In addition, the experiment results also demonstrate that MrNet has the capability of diagnosing the fault types accurately under the interference of noise signals (Laplace noise and Gaussian noise).

Design of a Mini Rice Harvester for Rural and Small Scale Rice Farmers in Tropical and Developing Countries

Food insecurity, price volatility and under-employment of rice farmers in Liberia are key drivers for the development of rice farming machines locally. This project work aims to design and fabricate a simple, low-cost, efficient mini rice harvester powered by a solar panel by translating learnt concepts and principles of engineering into a physical and workable rice harvester. A circular blade cutter, DC motor, DC battery and solar cells are the main components deployed on a rod-plate setup. The solar cell taps solar irradiance from the sun and, with the help of a charge controller, recharges a 12V, 35Amp.hour battery. The battery supplies DC current to a DC motor that drives a circular blade cutter during harvesting. The fabricated harvester fulfilled all design objectives and was justifiable on overall financial cost (USD 194.00), ease of use, and ease of reproduction. The performance of the harvester, in terms of smoothness of cut and completion of cut area, was found to be near 100%. However, the harvester field efficiency performance was found to be 30.75% with an aggregated efficiency of % and a payback period of only 71 hours of operation, equivalent to 60,696 sq.m of harvested rice farm. Incessant clogged cutter's surface and harvested stem removal delays, slowdowns as the operator makes turns, switch failures and re-fix delays during field tests are the primary causes of the low field efficiency. With an improved spacing between the blade cutter and the secondary guard, the performance of the harvester is expected to improve significantly. An average noise level of 88.8 decibels was detected during the harvester's operation; advisably, hearing protection earmuffs may be necessary to safely operate the mini harvester on the dailies for 6 hours. Notwithstanding that the effect of moisture content of the rice stalks, as an input parameter, was not considered in the development of the power requirement for the rice cutter, the harvester can be optimized with minimal effort for commercialization and adopted as a Made-In-Liberia invention.

Reed switch protection of double-circuit lines without current and voltage transformers

Protection of 6–35 kV double‐circuit lines from the supply side is suggested. It allows saving copper, steel, and high-voltage insulation in amounts unprecedented for relay protections. The protection is based on the control of sequence of actuation of reed switches fastened near the corresponding phases at a safe distance and of the time Δt between their actuation. The effect of all possible errors on Δt is studied and the number of reed switches required to be mounted near the phases of the lines is determined. The peculiarities of selection of Δt and inductions for the protection operation, points of reed switch mounting, sensitivity estimates, and the fields of use of the protection are analyzed. An example of the selection is considered. The protection operation algorithm is formulated and written in the form of switching algebra functions with allowance for the protection operability in the case of reed switch failures. The correct operation of the protection is shown in all actual modes of operation of the lines (including the failure of one of reed switches). A construction for fastening reed switches at a safe distance from the line phases is presented.

Few layer chemical vapor deposited two dimensional WS2 for low voltage resistive switching application

Optimizing the fabrication method gives rise to control over the deposition of WS2 sheets in a CVD chamber. The deposition was executed on Pt-coated silicon substrate so that electrical behavior of the WS2 domains could be observed. Utilizing two types of electrode material helped in understanding the role of metal diffusion mediated switching failure. The Au/WS2/Pt/Ti/SiO2/Si device exhibited resistive switching characteristics at very low operating voltages. A high on/off ratio (>104), high retention time (104 s), and a long endurance (1500 cycles) were respectively recorded to establish the non-volatile memory characteristics in a device with thin layer of WS2. The switching mechanism was established by performing conducting atomic force microscopy. This work also explained the mechanism of resistance switching in CVD grown tungsten disulfide in two steps and pave the way for the development of large-scale devices.

Overview of Intelligent Inverters and Associated Cybersecurity Issues for a Grid-Connected Solar Photovoltaic System

The major problem associated with the grid-connected solar photovoltaic (PV) system is the integration of the generated DC power into the AC grid and maintaining the stability of the system. With advancements in research on these PV inverters, artificial intelligence (AI)-based control models are replacing the existing linear methods. These smart PV systems are prone to a variety of attacks, ranging from physical attacks on the PV plants to data integrity attacks and communication-based attacks. This paper provides an overview of the cybersecurity issues with smart PV inverters, their impacts on the grids, and control methods that exist to detect and identify cyber-attacks on a smart PV grid system. An extensive bibliography is provided on grid-forming and grid-following inverters with a variety of control techniques like Proportional–Integral–Derivative (PID) control, fuzzy-based control, and their performances under different fault situations. Multi-level inverter design approaches with various intelligent control techniques to overcome switching failures and other system faults are reviewed. Moreover, some recommendations for future research on intelligent inverters for grid-connected PV systems are proposed. This work will benefit researchers, scientists, and engineers who are working in the field of intelligent inverters for the grid-connected PV system.

Reliability analysis of standby provision multi‐unit machining systems with varied failures, degradations, imperfections, and delays

AbstractThis prospective study focuses on analyzing the reliability characteristics of multi‐unit systems with standby provisioning, accounting for failures, degradation, random delays, and probabilistic imperfections. The investigation sheds light on how these unreliable attributes hinder the performance and availability of machining systems. Given the frequent occurrence of these negative attributes within machining systems, their impact on production flow, performance, and resource utilization is significant. Moreover, these unfavorable attributes hinder the adoption of advanced technologies that rely on the continuous availability of machining systems. Thorough research on operational traits serves as a foundation for developing solutions to enhance machining system efficiency and elucidates the underlying causes of machining system failures throughout their performance lifecycle. The reliability analysis employs a state‐of‐the‐art queue‐theoretic approach. In order to model the stochastic behavior of the investigated machine repair problem in a systematic manner, we consider various statistically independent failure modes, including active/standby unit failure, degraded failure, switching failure, and common‐cause failure. The unreliable characteristics of machining systems are further compounded by factors such as imperfect fault coverage, reboot delay, and imperfect repair, necessitating a comprehensive examination to strategically implement preventive, corrective, and predictive measures. The seamless operation of multi‐unit machining systems is essential for the successful integration of advanced technologies such as cloud computing, industry 4.0, and IoT. Failures, delays, degradation, and imperfections within machining systems have detrimental effects on their efficiency and availability, demanding in‐depth investigation. To facilitate numerical experimentation and sensitivity analysis of the reliability aspects of the proposed machining system, we develop performance indices such as system reliability, mean‐time‐to‐failure, and failure frequency. These metrics provide valuable insights for decision‐makers seeking to implement measures that ensure uninterrupted availability of the machining system.

A Novel Conditional Connectivity and Hamiltonian Connectivity of BCube with Various Faulty Elements

BCube is one of the main data center networks because it has many attractive features. In practical applications, the failure of components or physical connections is inevitable. In data center networks in particular, switch failures are unavoidable. Fault-tolerance capability is one main aspect to measure the performance of data center networks. Connectivity, fault tolerance Hamiltonian connectivity, and fault tolerance Hamiltonicity are important parameters that assess the fault tolerance of networks. In general, the distribution of fault elements is scattered, and it is necessary to consider the distribution of fault elements in different dimensions. We research the fault tolerance of BCube when considering faulty switches and faulty links/edges that distribute in different dimensions. We also investigate the connectivity, fault tolerance Hamiltonian connectivity, and Hamiltonicity. This study better evaluates the fault-tolerant performance of data center networks.

A Novel Pulse Compression Diode for Picosecond Pulse Generation

A novel pulse compression diode capable of generating high-voltage, picosecond pulses is introduced. The design concept and technical means of the novel diode based on semi-insulating gallium arsenide (SI-GaAs) materials are described, followed by the presentation of its static characteristics with three unique operating states. Typical output rise time for the novel diode with self-breakdown is limited to a few nanoseconds (1–2 ns). The basic physical mechanism affecting the fast conduction of the device is then analyzed, and the electrode structure is optimized as a consequence. Finally, a test circuit with a MOSFET as a preswitch is used as an example to verify the compression characteristics of the modified device. The experimental results show that the pulse front is sharpened from 32 ns to 853 ps and the full-width at half-maximum (FWHM) is sharpened from 120 to 2.1 ns by the pulse compression diode without extra triggering. Lifetime measurement experiments were conducted at a pulse repetition frequency of 100 Hz, revealing no instances of switch failures or malfunctions. The novel pulse compression diode has great potential for various applications, including in national defense, industrial, and medical sectors, due to its fast response, long lifetime, high reliability, and ease of series–parallel connection.

Can brexpiprazole be switched safely in patients with schizophrenia and dopamine supersensitivity psychosis? A retrospective analysis in a real-world clinical practice.

Several studies have reported that a switch to the dopamine partial agonist (DPA) aripiprazole (ARP), especially when the switch is abrupt, is likely to fail and sometimes worsen psychosis in schizophrenia patients already under high-dose antipsychotic treatment. Such a switching failure is speculated to be related to be the dopamine supersensitivity state. The risks of switching to the DPA brexpiprazole (BREX) have not been reported. We retrospectively analyzed the cases of 106 patients with schizophrenia to identify any factors related to the success or failure of switching to BREX. The comparison between the patients with dopamine supersensitivity psychosis (n = 44) and those without (n = 62) revealed no significant difference in the switching failure judged at the sixth week. A comparison of the patients with successful switching (n = 80) and those who failed (n = 26) revealed that patients with treatment-resistant schizophrenia (TRS) were significantly more likely to fail. A logistic regression analysis also revealed that patients with past failure of switching to ARP are likely to succeed in switching to BREX. The 2-year follow-up of the patients with successful switching to BREX suggested that the patients who were treated with BREX, even temporarily, experienced some improvement in their Global Assessment of Functioning and Clinical Global Impression-Severity scores. Overall, the results indicate that patients with schizophrenia can be switched more safely to BREX compared to ARP. However, the failure of switching to BREX could be higher in patients with TRS, and thus, starting BREX treatment in refractory patients warrants careful monitoring.

A NOVEL FAULT TOLERANT ASYMMETRICAL 21-LEVEL INVERTER TOPOLOGY WITH REDUCED COMPONENTS

The foremost objective of this work is to propose a fault-tolerant (FT) asymmetrical 21-level inverter with minimal power semiconductor switches and voltage sources. The topology of the proposed inverter is to produce high voltage levels with low harmonic content and minimize electromagnetic interference (EMI) in the system. Meanwhile, the novelty has been proved by a detailed comparison between the suggested multilevel inverter (MLI) and recently introduced topologies using several components such as switches, capacitors, sources, gate driving circuits, total standing voltage (TSV), component count per level and cost function. Additionally, the flexible circuit connection between sources, switches, and loads provides the alternative configuration for 21-level MLI to operate as a 9-level and 7-level MLI topology, ensuring FT capability during the failure of specific sources and switches. The nearest voltage level (NVL) algorithm technique produces gate driver signals for the switches, which generate high-quality waveform compared to other pulse width modulation (PWM) techniques. A simulation model is designed to support the simulation results using MATLAB/Simulink software and hardware implementation. The results are analyzed under different combinations of linear and nonlinear loads. In both simulation and experiment, the evaluated parameter values show good performance concerning other structures, and total harmonic distortion (THD) is less than 5 % as per IEE519 standards.

Constructing Multiple CISTs on BCube-Based Data Center Networks in the Occurrence of Switch Failures

The scale of data center networks (DCNs) has grown rapidly with the increasing popularity of cloud computing, data explosion, and the dramatic drop in setup costs. Thus, inevitable component failures (including switches and servers) will become more frequent. A DCN requires maintaining regular and reliable operation and providing efficient routing algorithms for transmitting data between servers. Particularly, fault-tolerant routing is necessary. Recently, constructing completely independent spanning trees (CISTs) on DCNs has received much attention as a dual-CIST (i.e., two CISTs) suffices to configure protection routing, which is a fault-tolerant routing. Moreover, the protection routing can additionally realize a secure mechanism if it is configured by more CISTs. BCube is a server-centric DCN with many advantages, and many variations were deformed from BCube with application requirements, such as RCube and RRect. In this paper, we provide a unified framework called BCube-based DCN (BDCN) that integrates the representation of the logic graphs of DCNs mentioned above, facilitating consistent algorithms' design. Then, we develop efficient algorithms to construct multiple CISTs on BDCN under the consideration of switch failures. Note that this is the first study that constructs multiple CISTs in DCNs with switch failures. Finally, using standard metrics, such as average path length (APL) and transmission failure rate (TFR), we evaluate the performance of the fault-tolerant routing through experiments.

Development of a Genset Monitoring and Control System via PLC DSE 7420 MK II on Automatic Transfer Switch (ATS) and Automatic Mains Failure (AMF) Panels at PT. XYZ

Listrik merupakan kebutuhan utama bagi PT. XYZ dimana harus selalu aktif dan kontinu ke semua bagian devisi PT. XYZ, terlebih dikhususkan pada devisi TI dimana harus selalu tersuplai sumber listrik karena terkait pemantauan server jaringan dan keamanan data-data perusahaan yang harus selalu dipantau non-stop. Adapun permasalahan lainnya yang penulis dapatkan terkait belum ada parameter sensor engine yang mengharuskan operator untuk standby di lapangan pada saat terjadi pemadaman listrik PLN. Selain itu, untuk menjaga keawetan dan ketahanan usia genset perlu maintenance agar pada saat jadwal yang ditentukan untuk pengecekan maka akan menampilkan notifikasi alarm pada modul PLC ataupun pada SCADA. Metode yang digunakan pada penelitian ini adalah metode research and development yaitu pendekatan sistematis untuk mencari solusi baru, pengembangan sistem/inovasi baru untuk meningkatkan kinerja dari sistem kontrol dan monitoring genset di PT. XYZ. Adapun tujuan dari penelitian ini adalah untuk pengambilan data file lama pada Deep Sea 4620 dijadikan sebagai evaluasi perubahan, untuk monitoring dan tampilan notifikasi alarm parameter sensor engine, menampilkan notifikasi peringatan maintenance genset. Dari hasil penelitian tersebut dapat disimpulkan bahwa PLC Deep Sea 7420 MK II memudahkan operator untuk pengoperasian dan monitoring jarak jauh tanpa langsung turun lapangan, mampu mengontrol perpindahan daya dengan cepat (0,7 detik) sehingga server pada gedung devisi IT selalu aktif dan terjaga tanpa adanya pemadaman pada beban, mampu mengontrol dan memonitoring parameter sensor genset secara real time baik dari modul PLC, aplikasi SCADA Suite dan monitoring dari aplikasi web SCADA, mengoperasikan perawatan pemananasan genset setiap hari jumat pada pukul 17.30 WIB dengan durasi 10 menit, menampilkan notifikasi maintenance fuel bahan bakar saat mencapai 790 jam setara dalam 1 bulan dan memberi kemudahan dalam melakukan pemeliharaan secara rutin dan selain itu dengan adanya jadwal berkala memudahkan operator untuk perawatan berkala setiap bulan.

A Method Based on NGO-HKELM for the Autonomous Diagnosis of Semiconductor Power Switch Open-Circuit Faults in Three-Phase Grid-Connected Photovoltaic Inverters

With accelerating grid decarbonization and technological breakthroughs, grid-connected photovoltaic (PV) systems are continuously connected to distribution networks at all voltage levels. As the grid interaction interfaces between PV panels and the distribution network, PV inverters must operate flawlessly to avoid energy and financial losses. As the failure of semiconductor switches is the leading cause of abnormal operation of PV inverters and typically cannot be detected by internal protection circuits, this paper aims to develop a method for the autonomous diagnosis of semiconductor power switch open-circuit faults in three-phase grid-connected PV inverters. In this study, a ReliefF-mRMR-based multi-domain feature selection method is designed to ensure the completeness of the fault characteristics. An NGO-HKELM-based classification method is proposed to guarantee the desired balance between generalization and exploration capability. The proposed method overcomes the common problems of poor training efficiency and imbalances between generalization and exploration capabilities. The performance of the proposed method is verified with the detection of switch OC faults in a three-phase H-bridge inverter and neutral-point-clamped inverter, with diagnostic accuracy of 100% and 99.46% respectively.

Effect of Termination Region on Unclamped Inductive Switching Failure for 4H-SiC VDMOS

The effect of the termination structure on the unclamped inductive switching (UIS) failure is analyzed for two kinds of SiC MOSFET, where S-MOS and G-MOS termination structure are adopted. The MOSFETs are named as S-MOS and G-MOS according to the buses connecting with different electrodes in the termination region. The experimental results indicate that the avalanche energy G-MOS can withstand is 1.15 times larger than that of S-MOS. To understand what are the factors that lead to different UIS capabilities, further static measurements and hotpot mapping after UIS test are done, and technology computer aided design (TCAD) simulation also is done to further confirm the principle.

Tracking Control of Self-Restructuring Systems: A Low-Complexity Neuroadaptive PID Approach With Guaranteed Performance.

This article investigates the tracking control problem for a class of self-restructuring systems. Different from existing studies on systems with fixed structure, this work focuses on systems with varying structures, arising from, for instance, biological self-developing, unconsciously switching, or unexpected subsystem failure. As the resultant dynamic model is complicated and uncertain, any model-based control is too costly and seldom practical. Here, we explore a nonmodel-based low-complexity proportional-integral-derivative (PID) control. Unlike traditional PID with fixed gains, the proposed one is embedded with neural-network (NN)-based self-tuning adaptive gains, where the tuning strategy is analytically built upon system stability and performance specifications, such that transient behavior and steady-state performance are ensured. Both square and nonsquare systems are addressed by using the matrix decomposition technique. The benefits and feasibility of the proposed control method are also validated and confirmed by the simulations.

Switch Fault Detection and Localization for T-Type Converter

Over the past decade, multilevel converters have received considerable interest in medium voltage applications. A large number of active switches in a multilevel converter increases the probability of switch failure and decreases the reliability of the system. An open switch fault can lead to a malfunction of the whole system and should be diagnosed as soon as possible. In this paper, an open-switch fault diagnosis method for a five-level H-Bridge T-type converter is presented. The proposed fault detection method and the fault localization algorithm are based on the switching patterns and the converter output voltage level observation. This approach is capable to detect and localize an open circuit fault for all switches. First, it is validated by simulations in Matlab Simulink and Simscape toolbox environments. Experimental results are also presented and discussed to validate the simulation results.

Reliability analysis of multilevel and matrix converters used in more electric aircraft

AbstractThis paper presents the current scenario related to the application of power electronics converters in aviation industries, major challenges and their reliability aspects. Recent developments in power electronics have given a major breakthrough in the aviation industry. These developments are not only limited to the more electric aircraft (MEA) but also in the field of electric propulsion, popularised as electric propulsion aircraft (EPA). The aircraft requires a well‐established protection scheme of these converter topologies. The overall reliability of aircraft solely depends on its protection and fast mitigation of any fault if occurs in the cruise time. This paper aims to provide a comprehensive analysis of power converters applications in MEA and EPA. Further, a review of various topologies of Power Converters and their reliability assessment is also described in detail. The physics of Failure of switches, their lifetime estimation and thermal cycling have also been discussed. Finally, the reliability assessment of different topologies and their comparison has been discussed for overall performance enhancement of the MEA and EPA.