Device Battery Research Articles

Novel algorithms improve arrhythmia detection accuracy in insertable cardiac monitors.

Insertable cardiac monitors (ICMs) are commonly used to diagnose cardiac arrhythmias. False detections in the latest ICM systems remain an issue, primarily due to inaccurate R-wave sensing. New discrimination algorithms were developed and tested to reduce false detections of atrial fibrillation (AF), pause, and tachycardia episodes in ICMs. Stored electrograms (EGMs) of AF, pause, and tachycardia episodes detected by Abbott Confirm Rx™ ICMs were extracted from the Merlin.net™ Patient Care Network, and manually adjudicated to establish independent training and testing datasets. New discrimination algorithms were developed to reject false episodes due to inaccurate R-wave sensing, P-wave identification, and R-R interval patterns. The performance of these new algorithms was quantified by false positive reduction (FPR) and true positive maintenance (TPM), relative to the existing algorithms. The new AF detection algorithm was trained on 5911 EGMs from 744 devices, resulting in 66.9% FPR and 97.8% TPM. In the testing data set of 1354 EGMs from 119 devices, this algorithm achieved 45.8% FPR and 97.0% TPM. The new pause algorithm was trained on 7178 EGMs from 1490 devices, resulting in 70.9% FPR and 98.7% TPM. In the testing data set of 1442 EGMs from 340 devices, this algorithm achieved 74.4% FPR and 99.3% TPM. The new tachycardia algorithm was trained on 520 EGMs from 204 devices, resulting in 57.0% FPR and 96.6% TPM. In the testing data set of 459 EGMs from 237 devices, this algorithm achieved 57.9% FPR and 96.5% TPM. The new algorithms substantially reduced false AF, pause, and tachycardia episodes while maintaining the majority of true arrhythmia episodes detected by the Abbott ICM algorithms that exist today. Implementing these algorithms in the next-generation ICM systems may lead to improved detection accuracy, in-clinic efficiency, and device battery longevity.

Factors and Design Features Influencing the Continued Use of Wearable Devices.

The initial healthy uptake of wearable devices is not necessarily accompanied by sustained or continued use. Accordingly, this study investigates the factors influencing the continuous use of wearable devices with a particular emphasis on design features. We complemented the expectation-confirmation model (ECM) theoretical foundation with various design features such as trust, readability, dialogue support, personalization, device battery, appeal, and social support. The study employs a simultaneous mixed method research design denoted as QUANT + qual. The quantitative analysis leverages partial least squares structural equation modeling (PLS-SEM) using survey data collected from wearable device users. The qualitative analysis complements the quantitative focus of the research by providing insights into the results obtained from the quantitative analysis. We found that subjects tend to use wearables daily (60%) or several times a week (33%), and 91% plan to use them even more. Subjects indicated multiple usages for wearables. Most subjects were using wearables for healthcare and wellness (61%) or sports and fitness (54%) and had smartwatches wearable type (74%). The model explains 24.1% (p < 0.01) of the variance of continued intention to use. As a theoretical contribution, the findings support using the ECM as a theoretical foundation for explaining the continued use of wearables. Partial least squares (PLS) and qualitative data analysis highlight the relative importance that wearable users place on perceived usefulness. Most notable are tracking functions and design features such as device battery, integration with other apps/devices, dialogue support, and appeal.

Graphite Anodes for Li-Ion Batteries: An Electron Paramagnetic Resonance Investigation.

Graphite is the most commercially successful anode material for lithium (Li)-ion batteries: its low cost, low toxicity, and high abundance make it ideally suited for use in batteries for electronic devices, electrified transportation, and grid-based storage. The physical and electrochemical properties of graphite anodes have been thoroughly characterized. However, questions remain regarding their electronic structures and whether the electrons occupy localized states on Li, delocalized states on C, or an admixture of both. In this regard, electron paramagnetic resonance (EPR) spectroscopy is an invaluable tool for characterizing the electronic states generated during electrochemical cycling as it measures the properties of the unpaired electrons in lithiated graphites. In this work, ex situ variable-temperature (10-300 K), variable-frequency (9-441 GHz) EPR was carried out to extract the g tensors and line widths and understand the effect of metallicity on the observed EPR spectra of electrochemically lithiated graphites at four different states of lithiation. We show that the increased resolution offered by EPR at high frequencies (>300 GHz) enables up to three different electron environments of axial symmetry to be observed, revealing heterogeneity within the graphite particles and the presence of hyperfine coupling to Li nuclei. Importantly, our work demonstrates the power of EPR spectroscopy to investigate the local electronic structure of graphite at different lithiation stages, paving the way for this technique as a tool for screening and investigating novel materials for use in Li-ion batteries.

Hybrid AC-DC distribution system for building integrated photovoltaics and energy storage solutions for heating-cooling purposes. A case study of a historic building in Cyprus

One of the main concerns globally is the phenomenon of climate change thus we have to move to a cleaner and sustainable development in different energy sectors. An important step in this direction is the penetration of more renewables in the electricity grid. Therefore, with the increasing penetration of DC devices, the concept of hybrid AC-DC systems attract more and more attention. This study proposes an innovative hybrid storage system for buildings, in combination with a DC heat-pump to maintain thermal comfort, and a hybrid AC-DC distribution system for the interconnection of the photovoltaic system, battery and electrical loads of the building. Photovoltaics, battery and DC devices are connected to the DC part, avoiding losses from unnecessary conversions, while AC loads are connected to the AC part. This solution has been tested in a historical building in Cyprus and the results indicated significant benefits. For the case of the proposed system the imported energy (<5,4 kWh/day) is limited to the 1/3 compared to the case of typical prosumer. Finally, the overall share of renewables reaches values > 85%. This article describes the innovative system and assess its performance in real conditions regarding the energy consumption/production, indoor comfort conditions, and battery behavior.

On the electrochemical properties of lithium‑sulfur batteries

We report in this work the electrochemical analysis of lithium‑sulfur batteries (LSB) composed of sulfur and activated carbon (AC) as the positive electrode and lithium metallic as the negative electrode. Cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy (EIS) techniques were employed for the in-situ characterization of the coin cell battery device. Electrochemical studies were performed at different state-of-charge (SoC) in 5 %-steps, covering the 0 to 100 % range. Our major findings include a high specific capacity of 1044 mAh gsulfur−1, which decreased to 200 mAh g−1 after 150 cycles. At the same time, the coulombic efficiency increased during the discharge from 78 % to 99 % due to a progressive activation of the narrow pores present in AC structures. Galvanostatic EIS findings as a function of SoC helped us in predicting the SoC and state-of-health (SoH). A 1500-h self-discharge result was presented and analyzed, indicating the presence of a small leakage current of ca. 600 nA. All electrochemical findings were corroborated by a comprehensive ex-situ materials characterization using Raman, scanning electron microscopy, X-ray photoelectron spectroscopy, and energy-dispersive X-ray spectrometry techniques. The electrochemical (in-situ) and ex-situ characterization of electrodes and coin cell devices allowed us to provide a critical discussion regarding the overall characteristic exhibited by LSBs.

Ultra-Reliable Device-Centric Uplink Communications in Airborne Networks: A Spatiotemporal Analysis

This paper proposes an ultra-reliable device-centric uplink (URDC-UL) communication scheme for airborne networks. In particular, base stations (BSs) are mounted on unmanned aerial vehicles (UAVs) that travel to schedule UL transmissions and collect data from devices. To attain an ultra-reliable unified device-centric performance, the UL connection is established when the UAV-BS is hovering at the nearest possible distance from the scheduled device. The performance of the proposed URDC-UL scheme is benchmarked against a stationary UAV-centric uplink (SUC-UL) scheme where the devices are scheduled to communicate to UAV-BSs that are continuously hovering at static locations. Utilizing stochastic geometry and queueing theory, novel spatiotemporal mathematical models are developed, which account for the UAV-BS spatial densities, mobility, altitude, antenna directivity, ground-to-air channel, and temporal traffic, among other factors. The results demonstrate the sensitivity of the URDC-UL scheme to the ratio between hovering and traveling time. In particular, the hovering to traveling time ratio should be carefully adjusted to maximize the harvested performance gains for the URDC-UL scheme in terms of link reliability, transmission rate, energy efficiency, and delay. Exploiting the URDC-UL scheme allows IoT devices to minimize transmission power while maintaining unified reliable transmission. This preserves the device's battery and addresses a critical IoT design challenge.

Development of Modified Mesoporous Carbon from Palm oil Biomass for Energy Storage Supercapacitor Application

Energy storage system research including battery and supercapacitor devices has been studied to increase efficiency, lower their cost and improve environmental friendliness. Supercapacitor (SC) device offers high transient response and power density which suitable for many applications. The electrodes in supercapacitor device usually produced from highly porous carbon materials. In this study, the modified mesoporous carbon was produced from Palm empty fruit bunch (EFB) biomass. The production of mesoporous carbon was done using a low-temperature hydrothermal carbonization process. The mesoporous carbon from EFB biomass has shown good properties in terms of high surface area and porosity. To improve the electrical conductivity of the carbon the modification by nitrogen doping with ammonium chloride and urea was studied. The effect of different nitrogen sources on surface area and pore properties were reported. The modified mesopore carbon was tested in a symmetrical swagelok supercapacitor cell to evaluate the specific capacitance and efficiency using galvanostatic charge-discharge method. The modified mesoporous carbon with urea doped exhibits the highest specific capacitance of 121 F g-1 at current loading of 0.1 A g-1 in an aqueous 1M H2SO4 electrolyte. The modified mesoporous carbon with urea doped has lower internal resistance due to nitrogen from urea enhance the electronic conductivity of the electrodes and thus increase the supercapacitor performance.

Research on short-circuit fault-diagnosis strategy of lithium-ion battery in an energy-storage system based on voltage cosine similarity

In recent years, accidents such as spontaneous combustion and explosion have frequently occurred in the field of electrochemical energy storage, and thermal runaway caused by short-circuit faults in lithium-ion (Li-ion) batteries is one of the main reasons. This study investigated the internal short circuit (ISC) fault diagnosis method for Li-ion (LiFePO4) batteries in energy storage devices. A short-circuit fault diagnosis method for battery module components based on voltage cosine similarity is proposed based on the characteristics extracted from the ISC fault battery. In this method, the voltage and current of the battery were used to derive a two-dimensional feature vector, and a gain multiple with excitation information was introduced to perform secondary processing on the eigenvectors and achieve effective separation of the fault-signal features. The experimental results show that the proposed method can achieve a second-level rapid diagnosis of short-circuit faults in batteries when the simulated ISC resistance is below 5 Ω, and the excellent fault-detection capabilities for modules with inconsistent states of charge and the performance of the proposed method under dynamic conditions are verified.

Diverse e-cigarette regulations in the Asia Pacific: A health economic perspective.

Diverse e-cigarette regulations in the Asia Pacific: A health economic perspective.

Aqueous Batteries for Human Body Electronic Devices

In the pursuit of convenient and healthy lives, human body electronic devices with interactive, medical, and communication functions have been gradually developed, propelling research into high-safety aqueous batteries as energy hubs. Despite extensive research progress, the application of aqueous batteries in human body electronic devices is still at the proof-of-concept stage. In this Focus Review, we comprehensively summarize the design strategies and research advances in the rational coupling of electrochemical properties with mechanical properties, degradability, and biocompatibility for aqueous wearable and implantable degradable batteries. The challenges and perspectives for the further development of aqueous batteries for human body electronic devices are outlined to guide research toward next-generation aqueous batteries for practical applications in the human body.

Simulation Studies on the Design and Analysis of Interdigital and Fractal-Based Micro-Supercapacitors

Micro supercapacitors (MSC) are recently replacing traditional batteries in flexible and portable electronic devices owing to their outstanding features such as high power density and long cycle life. In-plane supercapacitors are usually built in an interdigital electrode (IDE) structure because of its fabrication simplicity and flexibility. This helps to reduce ion diffusion length and enables easy on-chip integration of the device. Recent researches show that by replacing the interdigital electrode structure with the new architecture technique of Fractal electrode design, the effective area of the electrode-electrolyte interface and capacitance can be increased. This work investigates the effect of the device architecture on the energy storage capacity of in-plane MSCs. IDE and Fractal-based electrodes are simulated using COMSOL Multiphysics and analyzed for performance using cyclic voltammetry, galvanic charge-discharge technique and electric field distribution. The results indicate that the device with fractal design has more areal capacitance than the traditional interdigital structure. The highest capacitance was achieved by the proposed Sierpinski Fractal electrode design which exhibited 85.59% more areal capacitance than the conventional IDE. This can be attributed to the significant increase in effective electrode area and the edging effect of the electric field in the sharp edges of fractal electrodes.

ID: 213194 Optimizing Deep Brain Stimulation Parameters in Drug Resistant Epilepsy: An EEG Oriented Approach

Deep brain stimulation (DBS) of anterior thalamic nucleus (ATN) is establishing as an effective adjunctive therapy for patients with drug resistant epilepsy (DRE) not suitable for epilepsy brain surgery and/or vagal nerve stimulation. The success of ATN-DBS is dependent upon exact placement of the DBS electrodes and judicious selection of DBS parameters (DBSPs) and patients; even then, the success has been observed to be limited to mainly one form of intractable seizures (IS), namely complex partial seizures with other forms of IS failing to respond satisfactorily. Furthermore, the conventional mode of selection of DBSPs is by trial and error and the required adjustments in the DBSPs are governed by the clinical response in the seizure profile over the course of multiple sessions and hospital visits, thus, warranting a strong need for optimization of the DBSPs. We present an EEG-guided novel and superior approach to the selection of effective DBSPs that induces EEG-desynchronization which is known to possess potent antiepileptic property with possibly possession of an additional anti-kindling effect that can suppress and even arrest the ongoing process of epileptogenesis in the patients with DRE in addition to its primary role in exercising control over the IS. It is further claimed that the innovative EEG-guided approach can successfully optimize the DBSPs resulting in minimum sessions of DBSP adjustments reducing the frequency of hospital visits, minimum side effects and minimum consumption of the device battery thus prolonging its life. Preliminary results of the clinical application of the novel approach in the selection of the DBSPs in a small case series have been promising and encouraging despite which it is strongly recommended that well designed large sized studies are required for its validation and successful clinical outcome.

Location-aware hybrid microscopic routing scheme for mobile opportunistic network

&lt;p class="Abstract"&gt;&lt;span lang="EN-US"&gt;Mobile opportunistic networks (MON) has been used for provisioning delay-tolerant applications. In MON the device communicates with each other with no assured end-to-end paths from source and destination because of frequent topology changes, node mobility, low density, and intermittent connectivity. In MON the device battery drains very fast for performing activities such as scanning, transceiver, and other computational processes, impacting the overall performance thus, designing energy-efficient routing is a challenging task. The routing employs a store-carry-and-forward mechanism for packet communication, where the packet is composed of time-to-live (TTL) and is kept in buffer till the opportunity arises. In improving delivery ratio message replication has been adopted; however, induces high network congestion. Here we present a location-aware hybrid microscopic routing (LAHMR) scheme for MON. The LAHMR provides an effective packet transmission scheme with location awareness and high reliability by limiting unnecessary packets being circulated in the network. Experiment outcome shows the LAHMR scheme achieves a much better delivery ratio with less delay, and also reduces the number of a forwarder for transmitting a packet, aiding in the reduction of network overhead concerning recent routing method namely the social-aware reliable forwarding (SCARF) technique.&lt;/span&gt;&lt;/p&gt;

Comparative analysis of recent metaheuristic algorithms for maximum power point tracking of solar photovoltaic systems under partial shading conditions

&lt;span lang="EN-US"&gt;The photovoltaic (PV) system comprises one or more solar panels, a converter/inverter, controllers, and other mechanical and electrical elements that utilize the generated electrical energy by the PV modules. The PV systems are ranged from small roofs or transportable units to massive electric utility plants. The maximum power point tracking (MPPT) controller has been used in PV systems to get the maximum power available. In addition, the MPPT controller is much essential for PV systems to protect the battery devices or direct loads from the power fluctuations received from solar PV panels. There are several MPPT control mechanisms available right now. The most common and commonly applied approaches under constant irradiance are perturb and observe (P&amp;amp;O) and incremental conductance (INC). But such methods show variations in the maximum power point. In this sense, this paper analyses and utilizes two recent metaheuristic algorithms called artificial rabbit optimization (ARO) and the most valuable player (MVP) algorithm for MPPT applications. The performance comparisons are made with the most preferred traditional algorithms, such as P&amp;amp;O and INC. Based on the result obtained, this study recommends that ARO perform better in standard testing conditions than all the other algorithms, but in partially shaded conditions, the MVP algorithm performs better in terms of efficiency and tracking speed.&lt;/span&gt;

Impact of novel insertable cardiac monitoring system on real-world cardiac device clinic workflow

Abstract Funding Acknowledgements Type of funding sources: None. Background Insertable cardiac monitors (ICMs) continually monitor for cardiac arrhythmias, enabling appropriate therapeutic intervention. However, clinic workload to manage ICM patients can be significant. The recent LINQ II ICM system was designed with several features to streamline clinic practice, including remote reprogramming and on-demand data pull capabilities, tablet-based clinician device programmer, smartphone app-based patient monitor, patient management service, and elective data triaging service. Purpose To characterize the impact of the LINQ II ICM system on clinic workload compared to previous ICM systems. Methods A detailed workflow survey was taken by clinicians at 66 unique cardiac device clinics across UK/Ireland. The total number of ICM patients per clinic averaged 563 patients (median = 500). Respondents included cardiac physiologists (94%), cardiac nurses (4%), and physicians (2%). Results Overall, 82.5% of respondents reported that the LINQ II ICM system is more efficient compared to previous ICM workflow, with a total clinic time savings of 9.3 hours/week (Table). Use of a tablet-based device programmer was estimated to save 19.9 minutes per ICM patient during the initial device insertion and activation, while the patient management service saved 30.6 minutes per new patient on monitor set-up and education. Two-thirds (68.6%) of respondents reported that app-based patient monitoring increases efficiency of remote monitoring, attributable to fewer disconnected monitors and reduced patient calls due to information available in the app (e.g., device battery life, data transmission status). The majority (85.7%) felt that remote reprogramming increases efficiency, as remote reprogramming was estimated to save an average 20.0 minutes of staff time compared to an in-clinic reprogramming. More frequent reprogramming of device alerts also led to an average 13.5% reduction in the rate of non-actionable ICM alerts, and overall 43.1% fewer in-person clinic visits. Conclusions New ICM system features appear to streamline the clinic workflow associated with managing ICM patients, freeing up valuable clinician time to devote to patient care activities.

Combining functionalized CNT film with CuS microflowers through hyperbranched polymers for a flexible and appliable rechargeable Mg battery

The flexibility and high tolerance for mechanical deformation of batteries under operation is a critical aspect of flexible energy storage devices. In this paper, a large-area CNT film (CF) is prepared via chemical vapor deposition (CVD) method and then functionalized with hyperbranched polymers (HP) using the thiol-ene click reaction. CuS microflowers are in-situ grown on the flexible CNTs, where HP significantly enhances interfacial compatibility and greatly enhances the combination of CuS nanosheets with CNTs substrate. The modification strategy effectively promotes Mg2+ conversion reaction of CuS and greatly enhances the stability of the flexible electrode. The as-prepared flexible CuS/CF-HP cathode delivers a high magnesium storage capacity of 178 mAh g−1 at 50 mA g−1 and a good rate performance of 94 mAh g−1 at 2 A g−1, with a high Mg2+ diffusion coefficient of about ∼10−12 cm2 s−1 and a capacity retention rate of 79.2% after 200 cycles at 200 mA g−1. Furthermore, a practical flexible thin-film rechargeable Mg battery device based on the CuS/CF-HP cathode and Mg powder/CF anode was fabricated in a sealed polydimethylsiloxane package. The flexible full battery provides an outstanding power output as well as remarkable mechanical durability, demonstrating its potential applications for flexible energy storage devices.

Freeing the Animal Model: A Modular, Wirelessly Powered, Implantable Electronic Platform.

Fully implantable electronic devices in freely roaming animal models are useful in biomedical research, but their development is prohibitively resource intensive for many laboratories. The advent of miniaturized microcontrollers with onboard wireless data exchange capabilities has enabled cost-efficient development of myriad do-it-yourself electronic devices that are easily customizable with open-source software ( https://www.arduino.cc/ ). Likewise, the global proliferation of mobile devices has led to the development of low-cost miniaturized wireless power technology. The authors present a low-cost, rechargeable, and fully implantable electronic device comprising a commercially available, open-source, wirelessly powered microcontroller that is readily customizable with myriad readily available miniature sensors and actuators. The authors demonstrate the utility of this platform for chronic nerve stimulation in the freely roaming rat with intermittent wireless charging over 4 weeks. Device assembly was achieved within 2 hours and necessitated only basic soldering equipment. Component costs totaled $115 per device. Wireless data transfer and wireless recharging of device batteries was achieved within 30 minutes, and no harmful heat generation occurred during charging or discharging cycles, as measured by external thermography and internal device temperature monitoring. Wireless communication enabled triggered cathodic pulse stimulation of the facial nerve at various user-selected programmed frequencies (1, 5, and 10 Hz) for periods of 4 weeks or longer. This implantable electronic platform could be further miniaturized and expanded to study a vast array of biomedical research questions in live animal models. The clinical relevance of electrical stimulation in neural recovery remains controversial, and long-term neural stimulation in small animal models is challenging. We have developed a low-cost, fully implantable, wirelessly powered nerve stimulation device to facilitate further research in nerve stimulation in animal models.

Oxide Coating Role on the Bulk Structural Stability of Active LiMn2O4 Cathodes.

The protective coating of the electrode materials is a known source of improvement of the cycling performances in battery devices. In the case of the LiMn2O4 cathodes, the coating with a thin alumina layer has been proven to show performance efficiency. However, the precise mechanism of its effect on the performance improvement of the electrodes is still not clear. In this work we investigate alumina-coating-induced effects on the structural dynamics of the active materials in correlation to the modified solid electrolyte interface dynamics. The local structures of coated and uncoated samples at different galvanostatic points are studied by both soft X-ray absorption measurements at the Mn L-edges and O K-edge (in total electron yield mode) and hard X-ray absorption at the Mn K-edge (in transmission mode). The different probing depths of the employed techniques allowed us to study the structural dynamics both at the surface and within the bulk of the active material. We demonstrate that the coating successfully hinders the Mn3+ disproportionation and, hence, the degradation of the active material. Side products (layered Li2MnO3 and MnO) and changes in the local crystal symmetry with formation of Li2Mn2O4 are observed in uncoated electrodes. The role of alumina coating on the stability of the passivation layer and its consequent effect on the structural stability of the bulk active materials is discussed.

A mini review on alloy-based anode materials for Mg-ion batteries

There is a growing call for secondary batteries in superior-performance energy storage devices. The existing ruling Li-ion batteries are restricted by cost, accessibility of resources, and their theoretical capacities. So, scientists have explored substituted batteries. Rechargeable Mg-ion batteries are fascinating of the substitute metal-ion batteries owing to the Mg-ion obtainability in the soil, low price, protection, more volumetric energy density, and environment-friendliness. Mg-metal anodes function in the electrolytes reversibly, but these electrolytes are not suitable for superior capacity-producing transition metal cathodes owing to complicated surface spectacles. Conversely, transition metal oxides work well in the presence of conventional electrolytes, but these conventional electrolytes are not suitable for Mg metal anodes because of passivation spectacles that entirely block them. Alternative anodes that are replaced with Mg metal work reversibly in conventional electrolytes are the hopeful way to produce superior capacity and voltage Mg batteries. The current advancement in alloy-founded elements is discussed in this review. The various approaches, attainable capacities, reaction mechanisms, and electrochemical properties of ally-sort electrodes are scientifically discussed.

Tendency Regulation of Competing Reactions Toward Highly Reversible Tin Anode for Aqueous Alkaline Batteries.

Investigating dendrite-free stripping/plating anodes is highly significant for advancing the practical application of aqueous alkaline batteries. Sn has been identified as a promising candidate for anode material, but its deposition/dissolution efficiency is hindered by the strong electrostatic repulsion between Sn(OH)3 - and the substrate. Herein, this work constructs a nondense copper layer which serves as stannophile and hydrogen evolution inhibitor to adjust the tendency of competing reactions on Sn foil surface, thus achieving a highly reversible Sn anode. The interactions between the deposited Sn and the substrates are also strengthened to prevent shedding. Notably, the ratio of Sn redox reaction is significantly boosted from ≈20% to ≈100%, which results in outstanding cycling stability over 560 h at 10 mA cm-2 . A Sn//Ni(OH)2 battery device is also demonstrated with capacities from 0.94 to 22.4 mA h cm-2 and maximum stability of 1800 cycles.