batterydata/paper-abstracts huggingface dataset:
Cognitive and behavioural comorbidities are often seen in children with epilepsy, and are more common and severe in refractory epilepsy. These comorbidities are associated with worse quality of life, increased behavioural and language problems and worse social skills, all of which adversely affect long-term psychosocial functioning. To enable early intervention and therapy, children and teens with epilepsy should be periodically screened for cognitive comorbidities. The location of the epileptic focus can, to a certain degree, predict the type(s) of comorbidity; however, the spectrum of disability is often broad, presumably because focal perturbations can cause network dysfunction. Comorbidities often result from underlying structural or functional pathology that has led to seizures. In selected cases, therapy targeting the underlying cause, such as the ketogenic diet for GLUT1 deficiency syndromes, may be remarkably effective in ameliorating both seizures and cognitive concerns. In many cases, however, cognitive impairment persists despite seizure control. In epileptic encephalopathies, frequent seizures and/or interictal epileptiform abnormalities exacerbate neurocognitive dysfunction, owing to synaptic reorganization or impaired neurogenesis, or to other effects on developing neural circuits, and prompt initiation of effective antiepileptic therapy is essential to limit cognitive comorbidities.
Cooperation among nodes is fundamental for the operation of mobile ad hoc networks (MANETs). In such networks, there could be selfish nodes that use resources from other nodes to send their packets but that do not offer their resources to forward packets for other nodes. Thus, a cooperation enforcement mechanism is necessary. Trust models have been proposed as mechanisms to incentive cooperation in MANETs and some of them are based on game theory concepts. Among game theoretic trust models, those that make nodes’ strategies evolve genetically have shown promising results for cooperation improvement. However, current approaches propose a highly centralized genetic evolution which render them unfeasible for practical purposes in MANETs. In this article, we propose a trust model based on a non-cooperative game that uses a bacterial-like algorithm to let the nodes quickly learn the appropriate cooperation behavior. Our model is completely distributed, achieves optimal cooperation values in a small fraction of time compared with centralized algorithms, and adapts effectively to environmental changes.
In this work, we describe the use of unfolded graphene as a three dimensional (3D) conducting network for LiFePO4 nanoparticle growth. Compared with stacked graphene, which has a wrinkled structure, the use of unfolded graphene enables better dispersion of LiFePO4 and restricts the LiFePO4 particle size at the nanoscale. More importantly, it allows each LiFePO4 particle to be attached to the conducting layer, which could greatly enhance the electronic conductivity, thereby realizing the full potential of the active materials. Based on its superior structure, after post-treatment for 12 hours, the LiFePO4–unfolded graphene nanocomposite achieved a discharge capacity of 166.2 mA h g−1 in the 1st cycle, which is 98% of the theoretical capacity (170 mA h g−1). The composite also displayed stable cycling behavior up to 100 cycles, whereas the LiFePO4–stacked graphene composite with a similar carbon content could deliver a discharge capacity of only 77 mA h g−1 in the 1st cycle. X-ray absorption near-edge spectroscopy (XANES) provided spectroscopic understanding of the crystallinity of LiFePO4 and chemical bonding between LiFePO4 and unfolded graphene.
Video calls from mobile phones can improve communication during medical emergencies. Lay bystanders can be instructed and supervised by health professionals at Emergency Medical Communication Centers. Before implementation of video mobile calls in emergencies, issues of information security should be addressed.
Carbon aerogels have been prepared through a polycondensation of cresol (Cm) with formaldehyde (F) and an ambient pressure drying followed by carbonization at 900°C. Modification of the porous structures of the carbon aerogel can be achieved by CO2 activation at various temperatures (800, 850, 900°C) for 1–3h. This process could be considered as an alternative economic route to the classic RF gels synthesis. The obtained carbon aerogels have been attempted as electrode materials in electric double-layer capacitors. The relevant electrochemical behaviors were characterized by constant current charge–discharge experiments, cyclic voltammetry and electrochemical impedance spectroscopy in an electrolyte of 30% KOH aqueous solution. The results indicate that a mass specific capacitance of up to 78Fg−1 for the non-activated aerogel can be obtained at current density 1mAcm−2. CO2 activation can effectively improve the specific capacitance of the carbon aerogel. After CO2 activation performed at 900°C for 2h, the specific capacitance increases to 146Fg−1 at the same current. Only a slight decrease in capacitance, from 146 to 131Fg−1, was observed when the current density increases from 1 to 20mAcm−2, indicating a stable electrochemical property of carbon aerogel electrodes in 30% KOH aqueous electrolyte with various currents.
Self ordered arrays of titanium manganese mixed oxide nanotubes were prepared by anodization of Ti8Mn alloy (UNS R56080) under ultrasonication in diluted ethylene glycol containing fluoride. The dimensions of the nanotubes (diameter: 20–100nm and length: 0.5–2.0μm) could be tuned by changing the synthesis parameters. The as-anodized nanotubes showed a stoichiometry of (Ti,Mn)O2. Upon annealing at 500°C in oxygen atmosphere, the nanotubes contained a mixture of anatase+rutile phases of TiO2 and Mn2O3. The composition of the oxide nanotubes was influenced by the chemistry of the phases present in the alloy. More manganese content was observed in the oxide formed on the β-phase than in the oxide layer of α-phase. Anodization in the ultrasonic field increased the kinetics of nanotubular oxide formation and resulted in homogeneous ordering of the nanotubular arrays as compared to the anodization by conventional stirring in the fluoride containing ethylene glycol solution. Whereas, anodization in aqueous acidified fluoride solutions resulted in severe attack of the β-phase and did not show presence of nanotubular oxide structure.
In the extensive application processes of lithium ion batteries (LIBs), a great quantity of spent LIBs is producing, which is harmful to human and the environment if not handled properly. In addition, due to the scarcity of lithium on earth, sodium with relatively high abundance and low cost is expected to replace lithium. Hence, it is an interesting and urgent work of reusing the spent materials from the end-of-life LIBs for designing sodium-ion batteries (SIBs). Herein, an efficient method is proposed to recycle the spent LiMn2O4 and directly reuse it as the cathode of SIBs. As electrochemical tests show, such recycled LiMn2O4 delivers excellent Na-storage properties in SIBs. For example, its discharge capacity can gradually increase to 163.2 mAh g−1 over 50 cycles at 100 mA g−1, and the highest reversible capacity is up to 176.3 mAh g−1 at 20 mA g−1. It is further revealed by combining the electrochemical analyses and ex-situ characterizations that, the continuous increase of capacity during the initial 50 cycles is due to the phase transition of the spinel into layered structure caused by the Li+/Na+ (de)insertion. Studies of electrode kinetics indicate the faster ion diffusion in the layered material than the spinel one. This work provides a new strategy to recycle the spent LIBs, i.e., directly reusing the exhausted electrode materials to the next-generation batteries.
To develop asymmetric Zn-air battery with high voltage and power density, acidic stable bi-functional electrocatalyst for oxygen reduction reaction and oxygen evolution reaction plays an important role. Here, with two-dimensional metal-organic framework as precursor, a Co-Nx based electrocatalyst is synthesized. This electrocatalyst shows flaky shaped appearance. In its framework, Co-Nx and metallic Co particles with the size about 15–20 nm distribute evenly in N-doped mesoporous carbon matrix. In 0.1 M HClO4, its oxygen reduction reaction completes with a four-electron process. The onset and half-wave potentials are 0.86 and 0.82 V, respectively. The oxygen evolution reaction activity of this electrocatalyst is still outstanding. To obtain 10 mA cm−2 current, it merely requires a low overpotential of 328 mV. The electrocatalyst exhibits promising stability in both oxygen reduction reaction and oxygen evolution reaction process. With this electrocatalyst as cathode and Zn plate as anode, an asymmetric Zn-air battery is assembled. The open circuit voltage of this battery achieves 2.16 V with peak power density 300 mW cm−2. When discharge at 20 mA cm−2, its power density arrives at 1189 Wh·kg−1. This asymmetric Zn-air battery also shows attracting cycling stability during charge-discharge process and keeps constant for 15 h.
Customized hierarchical porous metal oxide arrays is of great importance for construction of high-performance electrochemical devices. In this work, we report hierarchical porous (HP)-NiO sheets arrays by a facile hydrothermal method. Interestingly, the obtained NiO sheets arrays show HP systems, and are composed of cat-ear-like sheets main structure and interconnected nanosheets secondary structure. Moreover, the secondary nanosheets are highly porous and consist of cross-linked nanoparticles of 30–100nm. The electrochemical performances of the HP-NiO sheets arrays are evaluated as anode for Li ion batteries. Compared with the normal NiO sheets arrays, enhanced electrochemical performances are achieved for the HP-NiO sheets, including higher capacity, better cycling life and high-rate capability. The HP-NiO sheets can deliver a specific capacity of 511mAhg−1 at 3Ag−1, higher than the normal NiO sheets arrays (374mAhg−1 at 3Ag−1), due to the hierarchical porous array configuration with large surface area, fast ion diffusion path and better accommodation of volume change.
The use of non-invasive ventilation (NIV) within paediatrics has increased significantly in recent years, probably due to improved understanding of its role and a rising confidence in its ability to provide respiratory support to children. NIV is a valuable treatment option for respiratory failure due to a variety of causes, both acute and chronic. Its ease of use allows its application in both the hospital and community setting. This article gives an overview of NIV use in the paediatric population, highlighting medical and nursing considerations that are important. Appropriate assessment, well-managed initiation with continued follow-up and support is vital for families and children embarking on NIV as a long-term respiratory support.
Single-chip PV water electrolysis device Microscale combustion for micro thermophotovoltaic systems Minority carrier blockade in MIND model solar cells International review of market deployment strategies for PV Monolithic a-Si alloy solar modules Microstructure of amorphous and microcrystalline Si and SiGe alloys GaN/AlGaN back-illuminated MQW Schottky barrier UV photodetectors
Meprins are secreted and membrane-bound metalloendopeptidases highly expressed in kidney and intestinal epithelial cells. They are oligomeric glycoproteins composed of evolutionarily related α and/or β subunits. The present work revealed that the messages for both meprin subunits were expressed in intestine and kidney in ICR and C3H/He mouse embryos (as early as day 11), indicating developmental functions for both subunits. During the first 2 weeks after birth, the mRNA levels for both subunits increased in ICR mice, but between 10 days and 3 weeks (time of weaning) the α subunit level in the intestine fell markedly. In adult ICR mice, meprin β mRNA was consistently expressed in both kidney and intestine, whereas meprin α mRNA was highly expressed in kidney but only present at low levels in intestine. In C3H/He mice, the pattern of meprin α and β subunit mRNA expression was similar to that of ICR mice, except that meprin α was barely detectable in kidney after birth. The results of postnatal studies indicate that the meprin α subunit has a role in the intestine during suckling but is not essential after weaning, and that the β homooligomer is the major meprin form after weaning in both kidney and intestine.
Substantial heterogeneity and defects in lithium-ion battery films can be a cause of material and battery failure. Although non-uniformity has been observed previously, the physical origin of electronic impedance non-uniformities in cathode materials has not been well-studied. We show that the local microscopic structure of materials strongly affects the resulting local impedance as measured by a micro-four-line probe, demonstrates large variation, and that these variations occur over sub-millimeter and larger distances on two different commercial cathode materials. These experimental results are further compared to modeled electronic and ionic transport pathways through the observed structure. By elucidating the extent and origins of heterogeneity in battery electrode films we provide a key principle through which batteries can be optimally designed to increase their safety, energy density, power, and longevity.
Single lithium-ion cells within electric vehicles’ battery packs generally show variations in capacity and impedance due to the manufacturing process as well as operational conditions. Therefore, cells connected in parallel experience different dynamic loads during vehicle operation, which may potentially result in uneven and accelerated aging behavior. However, in literature only little is mentioned about the different reasons for parameter variations within single cells of parallel connections as well as their magnitude in real-life conditions. In this work, capacity and impedance variations within parallel-connected cells are investigated theoretically and are quantified exemplary by a batch of new cylindrical 18650 cells as well as an retired BEV battery pack with a 2p96s configuration of prismatic cells. Furthermore, the development of existing parameter variations along cycling are analyzed for two modules of the battery pack. It is demonstrated, that the aged cells show a strong increased parameter spread compared to the new cells. During further aging, the existing capacities spread of the block and especially the state of inhomogeneity of parallel couples increases. Hence, the widespread theory of a self-balancing effect inside a parallel connection, which leads to a convergence of the cells’ SOH, is disproved.
In this investigation, nitrogen and sulfur co-doped graphene hydrogel (N,S-GH) with well-connected hierarchical networks was prepared using a simple one-step process. The hierarchical structures provide electrically conductive channels for ion transfer, whereas N,S heteroatoms improve the chemical reactivity and pseudocapacitance of the electrode material. An optimized N,S-GH as a bind-free supercapacitor electrode demonstrates a large gravimetric capacitance (294.8 F g−1 at 1 A g−1), long lifetime (89.4% retention after 10,000 cycles), and excellent rate capability, twice as that of pure GH due to the synergistic effect of N and S doping. Therefore, a large capacitance of the optimized N,S-GH is ascribed to fast ion diffusion, large accessible area (hierarchical network), and pseudocapacitance (N and S co-doping). Furthermore, the optimized N,S-GH-based supercapacitor delivers a high energy density (8.6 Wh kg−1) at a high power density (2.4 kW kg−1). Overall, the obtained N,S-GH through this investigation presents a promising electrode material with outstanding electrochemical properties for energy storage applications.
The lithium insertion and extraction dynamics of spinel LiMn2O4/carbon composite electrodes used in lithium-ion batteries have been investigated. A numerical model has been developed which rationalizes these electrodes as a bed of spherical Li1−δ Mn2O4 particles (0≤δ≤1, depending on the degree of insertion) with carbon as an electrically conducting additive, and with electrolyte filling the pores. It can be concluded from the simulations of potential step (PS) experiments that solid-state diffusion of lithium ions in the Li1−δ Mn2O4 particles and the electrochemical reaction at the Li1−δ Mn2O4 particle surfaces are simultaneously rate-determining. Their relative importance depends on the applied overpotential. Further, the diameter of the primary particles rather than that of the primary particle agglomerates was found to be relevant for the dynamics. From the simulations, we could evaluate a value of 2.8×10−13 cm2/s for the solid-state diffusion coefficient of lithium in Li1−δ Mn2O4 particles, a value of 5.5×10−8 cm/s for the standard heterogeneous rate constant, and a value of 0.30 for the transfer coefficient α.
A two-step hydrothermal process was developed to synthesize hydrous 30RuO2–70SnO2 composites with much better capacitive performances than those fabricated through the normal hydrothermal process, co-annealing method, or modified sol–gel procedure. A very high specific capacitance of RuO2 (C S,Ru), ca. 1150Fg−1, was obtained when this composite was synthesized via this two-step hydrothermal process with annealing in air at 150°C for 2h. The voltammetric currents of this annealed composite were found to be quasi-linearly proportional to the scan rate of CV (up to 500mVs−1), demonstrating its excellent power property. From Raman, UV–vis spectroscopic and TEM analyses, the reduction in mean particulate size is clearly found for this two-step oxide composite, attributable to the co-precipitation of (RuδSn1−δ)O2·xH2O onto partially dissolved SnO2·xH2O and the formation of (RuδSn1−δ)O2·xH2O crystallites in the second step. This effect significantly promotes the utilization of RuO2 (i.e., very high C S,Ru). The excellent capacitive performances, very similar to that of RuO2·xH2O, suggest the deposition of RuO2-enriched (RuδSn1−δ)O2·xH2O onto SnO2·xH2O seeds as well as the individual formation of (RuδSn1−δ)O2·xH2O crystallites in the second hydrothermal step.
Measurements of 1H and 7Li nuclear magnetic resonance (NMR) and ionic conductivity are reported for the polymer electrolytes formed by hydroxyethylcelluloses (HEC), poly(ethylene oxide) diisocyanate (DPEO) and LiClO4. The NMR experiments exhibit the qualitative features associated with Li+ and polymer chain mobilities in polymer electrolytes, namely the presence of well-defined 7Li and 1H spin–lattice relaxation rate maxima (T 1 −1). The single absorption band in the proton spectra and the observed 1H and 7Li exponential relaxation indicate that the HEC/DPEO/LiClO4 polymer electrolytes are predominantly amorphous. The conductivity values obtained by a.c. measurements rise above 10−4 S/cm at 370 K and are slightly higher for the samples with a greater oxygen content in the HEC molecule. The parameters estimated from the data indicate that the conductivity and the mobilities of Li+ and polymer chains are comparable to those found in the PEO8LiClO4 polymer electrolyte.
To study the electrochemical reaction on surfaces, phase interfaces, and crack surfaces in lithium ion battery electrode particles, a phase-field model is developed which describes fracture in large strains and anisotropic Cahn–Hilliard-Reaction. Thereby the concentration-dependency of the elastic properties and the anisotropy of diffusivity are also considered. The implementation in 3D is carried out by the isogeometric finite element method in order to treat the higher order terms in a straightforward manner. The electrochemical reaction is modeled through a modified Butler–Volmer equation to account for the influence of the phase change on the reaction on exterior surfaces. The reaction on the crack surfaces is considered through a volume source term weighted by a term related to the fracture order parameter. Based on the model, three characteristic examples are considered to reveal the electrochemical reactions on particle surfaces, phase interfaces, and crack surfaces, as well as their influence on the particle material behavior. The results show that both the anisotropy and the ratio between the timescales of reaction and diffusion can have a significant influence on the phase segregation behavior. In turn, the distribution of the lithium concentration strongly influences the reaction on the surface, especially when the phase interfaces appear on exterior surfaces or crack surfaces. The reaction rate increases considerably at phase interfaces due to the large lithium concentration gradient. Moreover, the simulations demonstrate that the segregation of a Li-rich and a Li-poor phase during delithiation can drive the cracks to propagate. The results indicate that the model can capture the electrochemical reaction on the freshly cracked surfaces.
This paper investigates the mechanisms of penetration induced thermal runaway (TR) propagation process within a large format lithium ion battery pack. A 6-battery module is built with 47 thermocouples installed at critical positions to record the temperature profiles. The first battery of the module is penetrated to trigger a TR propagation process. The temperature responses, the voltage responses and the heat transfer through different paths are analyzed and discussed to characterize the underlying physical behavior. The temperature responses show that: 1) Compared with the results of TR tests using accelerating rate calorimetry (ARC) with uniform heating, a lower onset temperature and a shorter TR triggering time are observed in a penetration induced TR propagation test due to side heating. 2) The maximum temperature difference within a battery can be as high as 791.8 °C in a penetration induced TR propagation test. The voltage responses have a 5-stage feature, indicating that the TR happens in sequence for the two pouch cells packed inside a battery. The heat transfer analysis shows that: 1) 12% of the total heat released in TR of a battery is enough to trigger the adjacent battery to TR. 2) The heat transferred through the pole connector is only about 1/10 of that through the battery shell. 3) The fire has little influence on the TR propagation, but may cause significant damage on the accessories located above the battery. The results can enhance our understandings of the mechanisms of TR propagation, and provide important guidelines in pack design for large format lithium ion battery.
Si doping at high voltage spinel LiNi0.5Mn1.5O4 are presented as an effective strategy to greatly increase the electrochemical performance. Well-crystallized LiNi0.5Mn1.5-xSixO4 (x=0.05, 0.10, 0.15, 0.20) with homogeneous Si distribution are successfully synthesized through solid-state reaction. Structural and electrochemical characteristics are investigated through FESEM, XRD, FTIR, Raman spectroscopy, cyclic voltammetry and galvanostatic charge/discharge testing. It can be demonstrated that Si doping significantly improves the electrochemical performance. LiNi0.5Mn1.35Si0.15O4 exhibits reversible capacities of 123 mAh/g after the 100th cycle at 0.5C and LiNi0.5Mn1.35Si0.15O4 as well as LiNi0.5Mn1.3Si0.2O4 show superior electrochemical stability over the pristine LiNi0.5Mn1.5O4 material. Since the Si-O bond exhibits high dissociation energy of 798kJ/mol (298K), which is far beyond of the dissociation energies of the Mn-O or Ni-O bonds, the excellent electrochemical performance might be associated with an increased structural and chemical stability caused by incorporation of Si into the Oxygen-rich crystal lattice.