Discharge Process Research Articles

Promoting Interfacial Reaction via Quantifying NMC811 CEI Evolution and Li+ Desolvation Using Single‐Particle Electrochemical Methods

AbstractPromoting interfacial kinetics of high‐nickel LiNi0.8Mn0.1Co0.1O2 (NMC811) is a critical strategy for enhancing rate capability of lithium‐ion batteries (LIBs). At the solid‐liquid interface of positive electrode, charge transfer across the cathode‐electrolyte interphase (CEI) is responsible for the interfacial redox reaction, which is dominated by desolvation process of Li+ and NMC811 CEI evolution. Since these two processes are significantly impacted by the solvation effect of electrolytes, herein single‐particle Raman spectroscopy and single‐particle probes are established to quantitatively study the influences of solvation effect on CEI evolution and desolvation process of Li+, respectively. Owing to oxidation of the unstable free cyclic carbonate ester from dissociation of solvation structure, the CEI is found to grow thicker during discharge process. Due to the decreased concentration of cyclic carbonate in the solvation structure, the desolvation process of Li+ in the ethyl methyl carbonate‐ethylene carbonate electrolyte can be reduced by 11.8% compared to that in the dimethyl carbonate‐ethylene carbonate electrolyte. With the presence of ethyl methyl carbonate‐ethylene carbonate electrolyte, thinner CEI and easier desolvation process of Li+ can be simultaneously achieved on the NMC811 surface. Accordingly, its corresponding LIBs deliver the highest specific capacity ≈138.8 mAh g−1 at 5C among the LIBs with the other commonly used electrolytes.

Dual-Driven Ion/Electron Migration and Sodium Storage by In Situ Introduction of Copper Ions and a Carbon-Conductive Framework in a Tin-Based Sulfide Anode.

Tin sulfide (SnS) has emerged as a promising anode material for sodium ion batteries (SIBs) due to its high theoretical capacity and large interlayer spacing. However, several challenges, such as severe insufficient electrochemical reactivity, rapid capacity degradation, and poor rate performance, still hinder its application in SIBs. In this study, in situ introduction of copper ions and a carbon conductive framework to form SnS nanocrystals embedded in a Cu2SnS3 lamellar structure heterojunction composite (SnS/Cu2SnS3/RGO) with graphene as the supporting material is proposed to achieve dual-driven sodium ion/electron migration during the continuous electrochemical process. The designed structure facilitates the preferential electrochemical reduction of copper ions into copper nanocrystals during the discharge process and functions as a catalytically active center to promote multivalence tin sodiation reaction. Furthermore, during the charging process, the presence of copper nanocrystals also facilitates efficient desodiation of NaxSn and further activates to form higher valence state sulfides. As a result, the SnS/Cu2SnS3/RGO composite demonstrates high cycling stability with a high reversible capacity of 395 mAh g-1 at 5A g-1 after 500 cycles with a capacity retention of 85.6%. In addition, the assembled Na3V2(PO4)3∥SnS/Cu2SnS3/RGO sodium ion full cell achieves 93.7% capacity retention after 80 cycles at 0.5 A g-1.

Stable electrochemical properties of trace titanium doping layered P3-type K0.5Mn0.92Ti0.08O2 cathode material for potassium ion batteries

The wide application of potassium ion batteries (PIBs) urgently requires the development of ideal cathode materials with low cost, good reaction kinetics and structural stability. Here, a titanium-doped K0.5Mn0.92Ti0.08O2 cathode material for potassium ion batteries is developed by doping modification strategy using a high-temperature solid-state method. The structure and performance structure-activity relationship of binary K0.5Mn1-xTixO2 cathode materials doped with non-electrochemically active element Ti4+ are studied experimentally and theoretically. With the introduction of Ti4+, when the doping amount is <10 mol%, the doped solid solution is hexagonal P3 phase, and the transition metal layer spacing increases. The non-equivalent doping affects the relative content of Mn3+/Mn4+, smoothes the redox peak in the electrochemical process, reduces the doping formation energy, and improves the structural stability. The ex-situ XRD fine structure study of the electrochemical process shows that the structural change of the material during the discharge process is suppressed after doping. The best Ti-doped cathode material K0.5Mn0.92Ti0.08O2 has an initial discharge capacity of 126.9 mAh·g−1 at a current density of 20 mA·g−1, and the capacity retention rate is 53.7 % after 100 cycles. This work provides a feasible strategy for the construction of stable electrode materials for PIBs.

Characterization of identical lithium-ion battery electrodes before and after charge/discharge cycles via in-plane large-area polishing

As an effective method to fabricate a large-area cross-sectional sample for lithium-ion battery electrodes, we perform in-plane polishing of LiNi0.8Co0.15Al0.05O2(NCA) cathode samples and obtain a large cross-sectional area with a diameter of 1.5 mm. The polished cross-sections of NCA cathode particles are sufficiently flat to perform the atomic force microscopy (AFM) measurements on each cathode particle. Following AFM-based Kelvin probe force microscopy and scanning spreading resistance microscopy measurements, an identical in-plane polished NCA sample is assembled into a coin cell for the charge and discharge processes. After 90 charge/discharge cycles, the in-plane-polished sample is successfully disassembled from the coin cell without causing critical damage. In addition, a microcrack structure, which is a typical degradation feature of the cycles of NCA particles, is observed for the identical in-plane polished NCA sample. This indicates that the in-plane polishing method is effective for investigating identical NCA electrode samples before and after the charge/discharge process. Furthermore, the in-plane polishing method can be successfully applied to the large-area polishing of a Si-based anode which is a mixture of Si carbon complexes and graphite particles. This study presents a novel methodology for analyzing the degradation of lithium-ion battery electrode materials.

Constructing dilute Mg-1.0In binary alloy: A pathway to enhanced anode performance in Mg-air battery

Magnesium anode is a critical material in Mg-air battery; however, the contradiction between mitigating self-corrosion and promoting activation poses a significant obstacle to the rapid advancement of primary magnesium batteries. Herein, this issue is addressed by constructing a dilute Mg-1.0In binary alloy with 1 wt% indium as the anode material. The equiaxed dendrites and moderate indium concentration gradient in the as-cast anode facilitate the formation of a protective surface film, leading to a low corrosion rate of 0.20 mm y−1 and enhancing the stability prior to discharge. Moreover, during the battery discharge process, this unique microstructure enables the redeposition of metallic indium and indium hydroxide, thereby dramatically accelerating the shedding of oxidation products and suppressing side hydrogen evolution reaction. The Mg-1.0In anode in a Mg-air battery delivers a discharge capacity of 1587 mA h g−1 and an average voltage of 1.46 V at 10 mA cm−2, outperforming most of previously reported magnesium anodes and the control samples with various indium contents. This work would inspire the achievement of superior Mg-air battery performance through the use of binary magnesium anode system in as-cast state, as opposed to a more complex and time-consuming multi-component anode design involving heat treatment and plastic deformation.

INVESTIGATION OF PLASMA VISCOSITY AND MAGNETIC FORCES IN COAXIAL PLASMA DISCHARGE DEVICE

This paper investigates the axial plasma current sheath, PCS viscosity force, and its correlation with other magnetic forces acting on it at three different radial positions (2.625, 3.625, and 4.125 cm) within the annular space between the coaxial electrodes system of plasma discharge device (12 kV-56 kA) with positive central electrode. The rate of change of PCS momentum was also investigated at these axial and radial positions. The discharge processes are carried out with an argon gas pressure of 0.8 Torr. Experimental results of azimuthal magnetic induction as a function of axial and radial positions and Navier Stokes equation were employed to compute exactly, the rate of change of PCS momentum, axial magnetic force, magnetic pressure gradient force, and viscosity force.

Unlocking success: Multidisciplinary rounds for effective discharge planning.

341 Background: Multidisciplinary rounds (MDR) streamline collaboration among healthcare professionals across various disciplines to devise patient progress and post-hospitalization transition plans. In our gynecology oncology inpatient unit, coordinating patient care involves multiple teams aiming for discharge objectives. While nurses oversee the care plan, physicians, advanced practice providers, case managers, and other key stakeholders possess essential insights to effective discharge planning. The aim of our study was to evaluate the impact of structured MDR implementation on discharge accuracy, effectiveness, and hospital throughput. Methods: In April 2022, our gynecologic oncology inpatient team implemented structured MDRs to enhance discharge processes, focusing on patient outcomes and hospital throughput. The initiative aimed to identify discharge barriers early, set goals, and address challenges collaboratively through: 1) Interdisciplinary Assessment: Using standardized tools to evaluate patient status and care needs; 2) Review of Clinical Data: Analyzing medical records via EHR systems; 3) Collaborative Decision-Making: Using decision-support tools to set the Estimated Discharge Date (EDD); 4) Patient Engagement: Involving patients and families in shared decision-making; 5) Documentation and Communication: Ensuring clear EDD documentation and effective communication through team huddles, bedside rounds, and discharge planning meetings. EDD reporting, discharge order timing, and patient discharge time were tracked using our Care Team Transformation Dashboard. Results: The implementation of structured MDR led to significant improvements in discharge processes. We observed enhanced accuracy in EDD, with a 2.9% increase, and a notable rise in the completion of discharge orders before 9 am, showing a 60.5% increase (Table). The percentage of patients leaving the hospital before noon increased by 20.4%, highlighting MDRs effectiveness in facilitating timely discharge, enhancing intradisciplinary collaboration, and streamlining discharge efficiency. Conclusions: MDRs play a pivotal role in improving teamwork, quality of care, and patient outcomes. Setting EDDs through structured MDR processes enhances proactive discharge planning, thereby reducing delays and optimizing patient flow, ultimately contributing to the delivery of high-quality, patient-centered healthcare. Measure Preintervention: 1/2023-1/2024 Postintervention02-05/2024 Percentage Increase EDD accuracy 1 day prior 46.9 48.3 2.9% Discharge orders before 9am 33.4 53.6 60.5% Discharges prior to noon 19.1 23.0 20.4%

Unconventional reservoir stimulation method based on electrohydraulic discharge shock and frequency resonance technology

To increase the production of unconventional oil and gas, it is necessary to improve reservoir porosity through reservoir reconstruction. High voltage electro-hydraulic discharge can generate strong shock waves, which not only meets the requirements of reservoir reconstruction, but also has the advantages of high efficiency and environmental protection, and has become a research hotspot. In order to further improve the effectiveness of reservoir transformation, a reservoir stimulation method based on electrohydraulic discharge shock and frequency resonance is proposed. Firstly, an electrohydraulic discharge equipment was designed, and according to the material and structure of the designed rod plate electrode, a theoretical electrohydraulic discharge model was built based on the bubble theory. The high voltage breakdown process under the condition of applied voltage of 12 kV and electrode gap of 2 mm is simulated in detail. The simulation results show that the discharge time is within 0.3 μs, and the extremely short discharge time not only produces strong shock waves, but also forms an arc channel to cause circuit damping oscillation. Then, an electrohydraulic discharge experimental platform was built according to the developed equipment. The discharge process was recorded by a high-precision oscilloscope, and the arc formation was photographed by a high-speed camera. The experimental results not only verify the correctness of the theoretical analysis, but also confirm that the developed electro-hydraulic discharge device can generate 0-60 Hz adjustable electrical pulses and has the ability to cause reservoir resonance. Finally, a comparative experiment was carried out with shale core samples to test the influence of resonance factors on the development of internal fractures in unconventional reservoir rocks. The CT scan images show that the shale fracture porosity in the resonance group increased by 46.4 %, which is much higher than that in the non-resonance group (11.8%). To further test the frequency resonance effect on reservoir reconstruction, a field test was carried out on the coalbed methane wells in Shanxi using the developed equipment. The experimental results show that the average gas production rate after on-site construction is increased from 11.46 m3/h to 12.49 m3/h, an increase of 8.99 %, indicating that the proposed technology can significantly promote the development of rock fractures and enhance the production recovery.

Construction and Analysis of Battery Equivalent Circuit Model Considering Liquid Phase Lithium Ion Diffusion Under High-Rate Conditions

In order to obtain the internal state of lithium-ion battery quickly and accurately, the problem that the internal state of the battery is difficult to estimate quickly and accurately is solved. The discharge performance of lithium ion is affected by the electrode current during the charge and discharge process. This paper analyzes the key factors of the electrochemical model at high rate, considers the change of lithium ion concentration in the liquid phase of the battery, integrates the electrochemical mechanism and the equivalent circuit, and establishes a mechanism equivalent circuit model with more computational advantages through circuit elements. The equivalent circuit model can describe the physical characteristics of the lithium battery. Under high rate constant current and dynamic conditions, the model shows good electrical characteristics. Compared with the traditional empirical equivalent circuit model, the accuracy of the model is improved, and the state quantity is reduced by 15 compared with the electrochemical model. The model is of great significance in practical application.

A study on the gas film formation in electrochemical discharging processes by molecular dynamics simulation

Molecular Dynamics (MD) simulations have emerged as a potent analytical tool for dissecting the intricate processes involved in nano gas film bubble generation. This study employs MD simulations to identify critical voltage that marks the transition from bubble saturation to gas film formation, while employing a mimic electrolysis model to expedite simulations through accelerated molecular insert rates. The simulations provide insights into underlying mechanisms, revealing the reforming and condensing dynamics of gas structures preceding gas film genesis. Experimental validation corroborates the accuracy of critical voltage predictions derived from MD simulations, with the close alignment between simulated critical points and experimental outcomes underscoring the robust predictive capability of MD simulations in elucidating electrochemical discharging (ECD) processes.

Effect of the negative-end discharge on the positive leader propagation in bidirectional leader discharges

Lightning strikes on aircraft are mainly due to self-triggered bidirectional leader discharges. Understanding the physical processes of lightning strikes is the basis for designing appropriate lightning protection measures. For this purpose, the development processes of bidirectional leaders triggered by a floating conductor were studied in a laboratory. In this paper, an experimental platform for the observation of bidirectional leader discharges is established through a reasonable gap arrangement. The discharge processes were recorded by a high-speed camera with up to 504 000 f/s. The effects of negative streamer discharges on the positive leader propagation speed as well as brightness during the bidirectional leader discharge at different electric field rise rates were mainly studied and quantitatively analyzed by introducing incremental coefficients. The experimental results show that the discharge development at the negative end of the floating conductor lags behind that at the positive end, and there is a coupling phenomenon between the positive and the negative discharge. At low electric field rise rates, when a negative streamer discharge occurs, it causes a positive corona burst, resulting in a sharp increase in brightness, while on the contrary the leader speed change is not as pronounced as the brightness change. As the rate of rise of the electric field increases, the effect of the discharge at the negative end on the positive end gradually decreases. This work could provide a theoretical basis for understanding the physical process of lightning strikes on aircraft.

A Digital Image Method for Calculating the Working Chamber Volume of a Combined Profile Scroll Compressor

Background: The efficient and accurate calculation of working chamber volume can greatly contribute to the optimized design efficiency of the combined profile scroll compressor, but current papers and patents lack research on the method of calculating the working chamber volume of a combined profile scroll compressor. Objective: A method of using digital image processing is proposed to efficiently calculate the working chamber volume of a combined scroll compressor. Methods: This method discretizes and reconstructs the scroll profile that forms the working chamber into a coordinate sequence with equal involute angle intervals. By calculating the relationship between the coordinate sequence and the rotation angle, a general coordinate sequence that forms the working chamber profile is obtained. The real-time changes in the projection image of the working chamber during all the suction, compression and discharge processes can be accurately depicted. The digital image is processed to obtain the actual projection area of the working chamber, and thus, the volume of the working chamber is accurately calculated. Results: The digital image method can accurately calculate the volume change of the working chamber of the combined profile scroll compressor by selecting the appropriate involute angle interval and digital image size, with a mean relative error of less than 1%. At the beginning of suction and the end of discharge, the calculated volume has been found to have poor accuracy, with a maximum relative error higher than 10%. Conclusion: The digital image method has been found to have high accuracy, greatly reduce the difficulty of the analysis of the working chamber volume, and promote the design optimization of the combined profile scroll compressor, thus broadening the idea for the calculation method of the working chamber volume of the scroll compressor.

A low voltage semiconductor arc discharge plasma actuator with long discharge gap distance

Long-gap spark discharge is beneficial for plasma-assisted combustion. However, the longer the discharge gap, the higher the breakdown voltage required, which is not feasible in practical applications. In the present study, based on a custom-built semiconductor, a long gap discharge plasma actuator is designed, and the breakdown voltage is relatively low compared with the normal spark discharge method. The breakdown discharge voltage for 25mm gap at atmospheric pressure is only 3.24kV. The discharge characteristics were investigated in detail. The influence of voltage, capacitance, and the semiconductor geometric parameters on the discharge characteristics is investigated. Based on a high-speed camera, the temporal and spatial long gap discharge process was captured firstly. Combined the discharge waveforms and images, the discharge process of the semiconductor arc discharge plasma actuator is divided into four stages: applying high voltage, surface discharge, air breakdown, and conduction discharge. Using digital image processing techniques, the influence of voltage, capacitance and air gap on surface discharge evolution velocity was studied.

Inpatient and postdischarge mortality among children with anaemia and malaria parasitaemia in Kenya: a cohort study

BackgroundAnaemia and malaria are leading causes of paediatric hospitalisation and inpatient mortality in sub-Saharan Africa. However, there is limited empirical data on survival following hospital discharge. We aimed to estimate...

Variation in NICU utilization: a narrative review and path forward.

Utilization of the Neonatal Intensive Care Unit (NICU) varies widely in the United States. Over recent decades, there has been a growth in NICUs, that varies by region, and has not been correlated to changes in demand or illness severity. Unnecessary NICU admissions are costly, stressful to families, may increase the risk of hospital acquired morbidities, and decrease breast feeding. Most of the variation in NICU utilization is based on the care of late preterm, early term, and term babies and is related to hospital level factors, including financial incentives, driving utilization. Improvement strategies to reduce variation include regionalization of care, certificate of need legislation, improving discharge processes, and caring for babies with some conditions such as Neonatal Opioid Withdrawal Syndrome or those with risk factors for sepsis outside of the NICU.

'You're Just Thinking About Going Home': Exploring Person-Centred Medication Communication With Older Patients at Hospital Discharge.

The hospital discharge process poses significant safety risks for older patients due to complexities in communication and coordination among stakeholders, leading to potential drug-related problems post-discharge. Adopting a person-centred care (PCC) approach in medication communication by healthcare professionals (HCPs) is crucial to ensure positive health outcomes. This study aimed to explore the practice of PCC in medication communication between older patients and HCPs during the hospital discharge process. We conducted a qualitative study using non-participatory direct observations of patient-HCP consultations during hospital discharge, followed by semi-structured interviews with observed patients and, when applicable, their informal caregivers. Data collection occurred from October 2020 to May 2021 at two Swedish hospitals. We gathered data using an observational form and audio-recorded all consultations and interviews. The data were analysed thematically using the systematic text condensation method. Twenty patients were included (median age: 81 years [range: 65-94]; 9 female) in observations and 13 of them participated in interviews. Two patients were accompanied by an informal caregiver during the interviews. Three main themes were identified: (1) The impact of traditional authoritarian structures, depicts power dynamics between patients and their HCPs, showing how traditional structures influence the practice of PCC in medication communication during hospital discharge; (2) Consultation timing and mode not on patients' terms, describes suboptimal times and settings for consultations, along with the use of complex language that hinders effective communication; and (3) Discrepancy in expectations of self-care ability, illustrates a mismatch between the self-care guidance provided by HCPs during hospital discharge and the actual needs and preferences of patients and informal caregivers. Medication communication between older patients and HCPs during hospital discharge is frequently inconsistent with the practice of PCC. Not only must HCPs improve their communication strategies, but patients and their informal caregivers should also be better prepared for discharge communication and encouraged to participate in their care. This involvement would give them relevant knowledge and tailor communication to their individual needs, preventing problems in managing their medications after discharge. An advisory group of six patients and/or informal caregiver contributors provided input on the study design, edited the consent forms, and helped develop the interview guide.

Optical and spectral techniques for studying high-voltage laser-triggered switch

In the present paper we have performed sets of experiments to study laser triggering high voltage switch. In this study, instead of electrical diagnostics, optical technique was utilized to characterize the discharge process. A Q-switched nanosecond Nd:YAG laser was used for triggering the switch. Dynamics of discharge, and the time delay of laser produced pre-plasma was monitored by fast photo diode signal which was connected to a fast oscilloscope. The spectrum of discharge emission was also recorded by photo spectrometer from which plasma parameters i.e. electron temperature, and density were estimated.

Mn-Based Transition Metal Oxide Positive Electrode for K-Ion Battery Using an FSA-based Ionic Liquid Electrolyte

Layered Mn-based transition metal oxides have gained interest as positive electrode materials for K-ion batteries due to their high capacity, excellent structural stability, and abundant resources. However, their practical utility is significantly hindered by insufficient electrochemical performances during operations. This study reports the successful synthesis of P3-K0.46MnO2 via the solid-state method and investigates its charge–discharge behavior as a positive electrode working in an FSA-based (FSA= bis(fluorosulfonyl)amide) ionic liquid electrolyte at 298 K. The K0.46MnO2 electrode demonstrates superior performance compared to previously reported K x MnO2 counterparts, delivering a reversible discharge capacity of about 100 mAh g−1 at a current density of 20 mA g−1 and a capacity retention of 68.3% over 400 cycles at 100 mA g−1. Ex situ X-ray diffraction analyses confirm the occurrence of reversible structural changes during the charge–discharge process. Further, we explore potassium storage mechanisms through ex situ synchrotron soft X-ray absorption spectroscopy. Spectra obtained in Mn L-edge region suggest that Mn is reversibly oxidized and reduced during K+ deintercalation and intercalation processes. Remarkably, discharging the electrode below 2.3 V induces reversible formation of Mn2+ from Mn3+/4+ on the electrode surface. The study demonstrates superior electrochemical performance of K0.46MnO2 positive electrode for K-ion battery using ionic liquid electrolyte.

PROPEL Discharge: An Interdisciplinary Throughput Initiative

BackgroundIncreased care demands at a healthcare institution led to strained resources, emergency department (ED) congestion, safety events, and patient and employee dissatisfaction. Moreover, high volumes of afternoon discharges contributed to limited early morning bed availability and admission bottlenecks. MethodsA 29-month pre-post design quality improvement project on 19 acute care, adult medicine units across two campuses at a large academic medical center was implemented to improve discharge timeliness, length of stay (LOS), and ED throughput by increasing pre-11:00 AM discharges. Based on Lean Six Sigma methodology, interventions included standardized interdisciplinary discharge processes and roles, processes to ensure performance data transparency and access, a recognition program, and a barrier tracking and mitigation process for continued improvements. ResultsDuring the intervention period, pre-11:00 AM discharges increased from 5.1% to 21.8% (p < 0.001), discharge orders were entered 42 minutes earlier (p < 0.001), patients were discharged 56 minutes earlier (p < 0.001), the percentage of discharges completed within 90 minutes from discharge order improved from 26.2% to 38.1% (p < 0.001), the percentage of discharges by 3:00 PM improved from 44.7% to 55.9% (p < 0.001), ED admissions arrived to units 44 minutes earlier (p < 0.001), median LOS decreased by 0.46 days (p < 0.001), median O:E LOS decreased by 0.05 (p < 0.001), and opportunity day reductions contributed to increased bed capacity of 18.84 beds per day. ConclusionEarly morning discharges are associated with improved patient throughput and are safe, achievable, and sustainable via interventions focused on frontline engagement, interdisciplinary collaboration, standardization, barrier mitigation, data accessibility, and accountability.

Experimental and Numerical Study on Scroll Compressor under Different Profile Correction and Discharge Ports Shapes

The scroll compressor is an essential component in air conditioning and heat pump systems. This study examined an electric scroll compressor using R22 refrigerant, focusing on how modifications in the scroll head profile and discharge structure affect its performance. Initially, a semi-empirical model based on mathematical formulas was developed to predict the performance improvements of the updated scroll compressor. Three-dimensional simulation software was then used to illustrate changes in the internal flow dynamics before and after enhancements. The predictions were validated through experimental testing. Both the semi-empirical model and the three-dimensional unsteady numerical calculation model analyzed the effects of modifications to the tooth head profile and discharge port shape on compressor performance. The adoption of a PMP profile correction delayed the compressor discharge process, shifting the starting discharge angle from 315°to 344°, thereby reducing under-compression occurrences during operation and increasing volumetric efficiency by 1.31%. Additionally, mathematical formulas correlating temperature with compressor performance were developed from fitting data, predicting compressor behavior under various conditions. Moreover, replacing a circular discharge port with a waist-shaped port reduced power consumption by 0.59 kW, resulting in a more uniform temperature distribution and enhanced mass flow rate during compressor operation.