Super-capacitor energy storage system to recuperate regenerative braking energy in elevator operation of high buildings

<span>In operating phases of elevators, accelerating, braking modes occur frequently, so braking energy recuperation of elevators has contributed considerably to decrease the total electric energy consumption for operating elevators in multi-floor buildings. In this paper, the supercapacitor energy storage system is used to recover regenerative braking energy of elevators when they operate down full-load and up no-load, reducing fluctuation of voltage on DC bus as well. Therefore, super-capacitor energy storage system (SCESS) will be parallel with line utility to recuperate regenerative braking energy in braking phase and support energy for acceleration phase. The surplus energy will be stored in the supercapacitors thanks to a DC-DC converter capable of exchanging energy bidirectionally in buck/boost modes, and designing control strategy including two control loops. Inner loop-current loop: controlling charge/discharge process of supercapacitors by current iL complying with operation characteristic of elevator; Outer loop-voltage loop: managing UDC-link at a fixed value. Simulation results with elevator system of the ten-floor building, Hanoi, Vietnam installed SCESS have been verified on MATLAB Simulink, SimPowerSystem with saving energy level about 30%.</span>

Fast-track hospital end-of-life discharge pathway: is it actually fast? National clinical audit

ObjectivesTo determine adherence to Department of Health and Social Care target of fast-track pathway discharge for end-of-life care within 48 hours.MethodsMulticentre audit in England using retrospective analysis of patient records for fast-track pathway tools submitted between 1 March 2019 and 31 March 2019.ResultsMost patients (72%) were not discharged within the 48-hour target. There was significant variability in success between hospital sites. Delays in discharge were most frequently considered to be secondary to delays in sourcing packages of care and 24-hour care facility placements. Involvement of specialist discharge nurses in paperwork submission improved rates by Commissioning Care Groups. Patients who died in hospital had significantly longer admissions than those who were discharged (discharged 19 days (IQR 11–28) vs died 28 days (IQR 18–42); p=0.039). This was entirely accounted for by increased numbers of days between admission and first suggestion of fast-track pathway discharge in those who died in hospital (discharged 9 days (IQR 5–19), died 15 days (IQR 9–33); p=0.003).ConclusionsWe demonstrated a delay in the fast-track pathway discharge process with significant variation in success of the discharge process at different geographical locations.

Lifetime and Aging Degradation Prognostics for Lithium-ion Battery Packs Based on a Cell to Pack Method

Aging diagnosis of batteries is essential to ensure that the energy storage systems operate within a safe region. This paper proposes a novel cell to pack health and lifetime prognostics method based on the combination of transferred deep learning and Gaussian process regression. General health indicators are extracted from the partial discharge process. The sequential degradation model of the health indicator is developed based on a deep learning framework and is migrated for the battery pack degradation prediction. The future degraded capacities of both battery pack and each battery cell are probabilistically predicted to provide a comprehensive lifetime prognostic. Besides, only a few separate battery cells in the source domain and early data of battery packs in the target domain are needed for model construction. Experimental results show that the lifetime prediction errors are less than 25 cycles for the battery pack, even with only 50 cycles for model fine-tuning, which can save about 90% time for the aging experiment. Thus, it largely reduces the time and labor for battery pack investigation. The predicted capacity trends of the battery cells connected in the battery pack accurately reflect the actual degradation of each battery cell, which can reveal the weakest cell for maintenance in advance.

Formation and destruction of striation plasmas in helium glow discharge at medium pressures

The striation plasmas are usually generated in positive column of glow discharge, in which abundant and complex physics are involved, especially, in medium or high pressures. This paper was aimed at investigating the formation and deformation of helium striation plasmas at kPa level pressures. The characteristics of helium striation plasmas, especially, the optical emission characteristics were investigated. The emission lines of 706.52 nm and 391.44 nm related to energetic electrons and high energy metastable helium atoms were focused on during the discharge process. Formation of striation plasmas in helium glow discharge, is mainly associated with the instability resulting from stepwise ionization vis high energy metastable state atoms, Maxwellization of electron distribution functions and gas heating. The deformation effect of helium striation plasmas is very significant when a small amount of nitrogen or oxygen is mixed into the discharge plasmas. The reduction of mean electron energy and the consumption of high energy metastable helium atoms are the potential reasons for deformation of striation plasmas.

Li-Ion Cell Safety Monitoring Using Mechanical Parameters: Part I. Normal Battery Operation

The normal operation of a 18650 Lithium-ion cells has been monitored using rectangular rosette strain gauge and a pair of piezoelectric transducers. The sensors for mechanical measurements provide information about the cell deformation mechanism and electrodes structure during the cycling. The strain gauge signal revealed three type of mechanical processes. The predominant deformation pattern during galvanostatic discharge process is an isotropic cylindrical shrinkage relevant to the extraction of lithium ions from the graphite negative electrode. In the case of low-rate discharge in cyclic voltammetry mode, the deformation pattern changes to spherical growth when the state of charge falls below 40. In contrast, the thermal shrinkage and growth of the cell corresponds to simple decrease of the cell diameter with much smaller hysteresis effect. The ultrasound interrogation is able to detect repeatable progressive change of the acoustic waveform transferred across the cell in direction of the jellyroll diameter, which depends on the state of charge and does not undergo any significant changes at different cycling rates. The impact of the state of health under 2h – rated charge/discharge cycling at 25°C reveals slow progressive drift of the strain and acoustic signals corresponding to the growth of the cell size.

Association Between The Discharge Process And Post-Discharge Events In Patients With Heart Failure

Background: HF is a burden on healthcare resources due to the high cost of frequent readmissions. Predictive models have been reported for the post-discharge prognosis of HF. However, these models mostly included non-modifiable factors and their predictive accuracy was limited. This implies that potentially modifiable factors are needed, which could be attributed to the discharge process. This study aimed to explore the relationship between the discharge process and post-discharge events in patients with HF.Methods: Medical records were reviewed to identify patients who were admitted for HF exacerbation. Information related to the discharge process included post-discharge clinic appointments, educational contents before discharge, and family participation during patient education. HF-related events were defined as a composite of events, including emergency department visits, readmissions, or death. A multivariable Cox proportional hazards regression model was used to explore the association between the discharge process and HF-related events.Results: Of 201 patients, 41 had at least one HF-related event. Post-discharge clinic appointments were scheduled 8 days after discharge. Patients received their discharge education on average of one topic, and approximately the families of 70% of the patients participated in this educational activity. In the Cox regression model, family participation during education was independently associated with a longer time to HF events (hazard ratio: 2.105). However, and post-discharge follow-up appointments and the number of educational contents received were not associated with the time to HF events. Conclusion: We found that family participation during education is a protective factor for adverse prognosis in patients with HF. Our results highlight the importance of family engagement in HF management.

Recent Developments in Supercapacitor Electrodes: A Mini Review

The use of nonrenewable fossil fuels for energy has increased in recent decades, posing a serious threat to human life. As a result, it is critical to build environmentally friendly and low-cost reliable and renewable energy storage solutions. The supercapacitor is a future energy device because of its higher power density and outstanding cyclic stability with a quick charge and discharge process. Supercapacitors, on the other hand, have a lower energy density than regular batteries. It is well known that the electrochemical characteristic of supercapacitors is strongly dependent on electrode materials. The current review highlights advance in the TMOs for supercapacitor electrodes. In addition, the newly discovered hybrid/pseudo-supercapacitors have been discussed. Metal oxides that are employed as electrode materials are the focus of this study. The discovery of nanostructured electrode materials continues to be a major focus of supercapacitor research. To create high-performance electrode materials from a morphological standpoint, various efforts have been attempted. Lastly, we analyze the supercapacitor’s evolving trend and our perspective for the future generations of supercapacitors.