batterydata/paper-abstracts huggingface dataset:
The aim of this study was to assess whether duration of seizure disorder and lifetime seizure load are associated with deficits in higher cognitive functions in patients with temporal lobe epilepsy (TLE) (N = 207) or psychogenic nonepileptic seizures (PNES) (N = 216). Multivariate regression analyses revealed that age at onset, duration, and group assignment were significant predictors of neuropsychological performance (all P ⩽0.02), with group having a moderating relationship. Univariate analyses revealed different patterns of predictor effects on cognitive functioning within each diagnostic group. An impairment index was calculated for each individual, and univariate analyses revealed that age at TLE but not PNES onset was the only significant predictor of impairment (b =–0.005, P < 0.001). The results suggest that earlier age at seizure onset, longer duration, and higher lifetime seizure frequency affect cognitive functioning in both the TLE and PNES groups, but differently within each group. These results have implications for early diagnosis and intervention in both groups.
The low Se loading, volumetric expansion and polyselenide shuttling between cathode and anode are major factors to limit the further development of Na-Se batteries. To overcome above issues, metal-organic complex derived hierarchical porous carbon (HPC) was synthesized as host matrix for Se via a facile synthesis combined with annealing treatment. The unique hollow structure holds numerous micropores and mesopores for Se loading to form Se-HPC composite. The Se-HPC electrode shows outstanding rate capabilities of 330 and 260 mA h g-1 at 1 C and 5 C, respectively. It also exhibits a stable cycling performance for 1000 cycles at 2 C with a small capacity decay rate of 0.04% per cycle. Such good performance demonstrates the viability of Na-Se batteries with high Se loading of 56%, which may be attributed to the unique hollow structure of HPC with Se encapsulated within micropores and mesopores. This attractive structure not only promotes electrolyte infiltration and electron transfer but also provides additional buffer space to buffer volumetric expansion of Se and suppress polyselenides dissolution in carbonate electrolyte during cycling.
A facile, template-free route using supercritical methanol for the preparation of hierarchical mesoporous Li4Ti5O12 spinel microspheres in a very short reaction time is introduced. Nanosized, primary Li4Ti5O12 particles (5–10 nm) are loosely aggregated and form micron-sized, secondary mesoporous spheres (0.2–2.0 μm) with a pore size of 2–10 nm. Subsequent calcination of the as-synthesized Li4Ti5O12 at a low temperature of 600 °C results in excellent long-term cyclability and high rate performance. The discharge capacity after 400 cycles at 1 C is 134.9 mAh g−1 (77.6% of the initial discharge capacity), and the discharge capacity at 10 C is 108.5 mAh g−1. The formation mechanism of hierarchical mesoporous microspheres in supercritical methanol is discussed.
Recently, we have reported a new all tungsto-cobalt heteropoly acid redox flow battery (all H6[CoW12O40] RFB) with high coulombic efficiency. Because of the relatively large ion size and high negative charge, the tungsto-cobalt heteropoly acid anion is difficult to cross Nafion membrane, which makes it possible to employ thinner Nafion membrane in all H6[CoW12O40] RFB. In this study, three types of Nafion membranes with different thickness, namely, N212 (50 μm), N211 (25 μm), and N-17 (home-made, 17 μm) are used as polymer electrolyte to investigate its effects on the performance of all H6[CoW12O40] RFB. The ion permeability increases while the area specific resistanceas decreases as reducing the membrane thickness. As a result, the RFB with N211 membrane exhibits best comprehensive performance, which exhibites the energy efficiency of 88.6% at current density of 0.10 A cm−2 and the power density of 0.56 W cm−2 at 0.60 A cm−2. Moreover, the battery delivers impressive cycling performance of 100 cycles with an average coulombic efficiency of 99.4%, energy efficiency of 80.0%, and capacity retention of 99.98% per cycle at current density of 0.20 A cm−2.
The study presented in this paper is based on a detailed review of the literature focused on the use of phase change materials (PCM) for photovoltaic (PV) module thermal regulation and electrical efficiency improvement. The influence of high temperature on PV power generation has been examined and the findings have highlighted the importance of effective thermal regulation for PV models. Various PV cooling methods employed to maintain better PV performance are discussed and the recently emerging PV–PCM system concept for thermal regulation is introduced. A comprehensive literature review of the state-of-the-art aspects of this technology, such as system development, performance evaluation, materials selection, heat transfer improvement, numerical models, simulation, and application in practice is given. The PV–PCM system, however, might not be economically feasible if the enhancement of PV efficiency only is sought. The PV–ST–PCM system, i.e. integrated with a solar thermal (ST) system, has therefore been investigated as the stored heat can be extracted for other thermal applications. The dual PCM roles demonstrate significant application prospects for the combined technology. However, both PV–PCM and PV–ST–PCM systems are still mainly in the research and laboratory test stages, with obvious scope for practical applications but with attendant challenges. Suggestions for the future work are presented.
A family of lithium mixed transition-metal pyrophosphates Li2Fe1−yMnyP2O7/C (0≤y≤1) has been prepared by mechanochemically assisted solid state synthesis using a high-energy planetary mill AGO-2. The samples were studied by X-ray powder diffraction (XRD) including Rietveld refinement, Fourier transform infrared spectroscopy (FTIR), Mössbauer spectroscopy, scanning electron microscopy (SEM), 6Li nuclear magnetic resonance spectroscopy (NMR), galvanostatic cycling, and galvanostatic intermittent titration technique (GITT). All samples were refined in a monoclinic framework (space group P21/c) with M ions occupying MO6 and MO5 sites and Li ions occupying LiO4 and LiO5 sites. The cell volume of Li2Fe1−yMnyP2O7 increases vs. Mn content with a slight deviation from the linearity. M2+ ion fractions in different coordination polyhedra and structural disordering among the Li and M sites in the as-prepared pyrophosphates were studied in detail by a multi-technique approach. According to galvanostatic cycling, only the Fe2+/Fe3+ redox couple operates upon the cycling of Li2Fe1−yMnyP2O7 in the 2.0-4.3V range, while the Mn2+/Mn3+ redox pair becomes active at higher voltage (∼4.8V). The Li2Fe0.75Mn0.25P2O7/C sample shows the highest discharge capacity of 87mAhg−1, close to the theoretical capacity delivered by the Fe2+/Fe3+ redox couple. A single-phase mechanism of lithium deintercalation was confirmed. Lithium diffusion coefficient D Li+ during the charge-discharge processes of Li2Fe0.75Mn0.25P2O7/C is within the range from 10−13 to 10−15 cm2 s−1 which is slightly higher than that of Li2FeP2O7/C.
The development of energy-sustainable and energy-efficient economy depends on the ability to produce low-cost high-performance renewable materials for electrical energy storage devices. The electrical double layer capacitors (EDLCs) with nanostructured activated carbon (AC) electrodes from natural precursors have attracted considerable attention due to their great cycle stability, combined with moderate cost and attractive overall performance. Such ACs offer high specific surface area, high electrical conductivity, relatively low price, easy and environmental friendly production in large quantities. The recent developments in the synthesis of such AC materials allow for the greatly enhanced specific capacitance in a wide range of electrolytes. This review provides a summary of a recent research progress in synthesis and understanding the critical structure-property relationships for nanostructured ACs and highlights the trends for the future developments of ACs for EDLC applications.
The conditions for the onset of natural convection (convective instability) in the electrochemical system consisting of two plane horizontal electrodes and solution containing three types of ions between them were analyzed theoretically. The equations of flow of incompressible viscous liquid to the Boussinesq approximation and the equations of material balance with the electroneutrality condition were used as the mathematical model. The set of equations for amplitudes of perturbations was solved using the Galerkin method. The dependences of critical Rayleigh number on the system parameters are obtained for monotonic and oscillatory instabilities in the case that the electrochemical reaction proceeds under the conditions of limiting current. The examples of instability diagrams are presented. In contrast to the binary electrolyte, for a solution containing three types of ions, the critical Rayleigh number depends on the charges of ions and the ratio between the diffusion coefficients of ions in the solution.
Ionic liquids (IL's) were proposed for use in Li-ion batteries (LIBs), in order to mitigate some of the well-known drawbacks of LiPF6/mixed organic carbonates solutions. However, their large cations seriously decrease lithium transference numbers and block lithium insertion sites at electrode-electrolyte interfaces, leading to poor LIB rate performance. Deep eutectic electrolytes (DEEs) (which share some of the advantages of ILs but possess only one cation, Li+), were then proposed, in order to overcome the difficulties associated with ILs. We report herein on the preparation, thermal properties (melting, crystallization, and glass transition temperatures), transport properties (specific conductivity and viscosity) and thermal stability of binary DEEs based on mixtures of lithium bis(trifluoromethane)sulfonimide or lithium bis(fluoro)sulfonimide salts with an alkyl sulfonamide solvent. Promise for LIB applications is demonstrated by chronoamperometry on Al current collectors, and cycling behavior of negative and positive electrodes. Residual current densities of 12 and 45 nA cm−2 were observed at 5 V vs. Li/Li+ on aluminum, 1.5 and 16 nA cm−2 at 4.5 V vs. Li/Li+, respectively for LiFSI and LiTFSI based DEEs. Capacities of 220, 130, and 175 mAh· g−1 were observed at low (C/13 or C/10) rates, respectively for petroleum coke, LiMn1/3Ni1/3Co1/3O2 (a.k.a. NMC 111) and LiAl0.05Co0.15Ni0.8O2 (a.k.a. NCA).
According to UNDP Policy Note 2014, only 23% of Yemen rural community have access to electricity – having connected to national grid or use small isolated generating units – while the country is one of the richest in solar energy with over 3000h per year clean blue sky. The objectives of this paper is to concentrate on the utilization and the cost effectiveness of photovoltaic solar energy for electrification of Yemeni rural and desert communities, which will result in enhancing education, culture, science, medical services, and improve the living conditions in rural areas. Otherwise, energy poverty that is a facet of a multidimensional poverty in Yemen will persists because the possibility of connecting rural communities to the national grid, even in the next ten years, is invisible due to major political and financial problems that the country is facing. Moreover, PV energy is environmentally clean and has proved to be one of the best solutions for rural electrification in many countries worldwide due to noticeable drop of PV systems prices with the advance in PV technology. Accordingly, it should be the best solution for rural electrification in Yemeni as well. The paper demonstrates the cost effectiveness and the design procedure of utilization of solar energy for rural and desert communities in Yemen using a number of subsequent cases typical to Yemeni communities and provides also a practical study to support Bedouin backpackers.
Mn-based Mn2O3 anode and LiMn2O4 cathode materials are prepared by a solvothermal method combined with post annealing process. Environmentally friendly ionic liquid 1-Butyl-3-methylimidazolium tetrafluoroborate as both structure-directing agent and fluorine source is used to prepare hollow polyhedron MnF2 precursor. Both target materials Mn2O3 anode and LiMn2O4 cathode have the morphology of the MnF2 precursor. The Mn2O3 anode using carboxymethyl cellulose as binder could deliver slight better electrochemical performance than the one using poly (vinyldifluoride) as binder. The former has an initial charge capacity of 800 mAh g−1 at a current density of 101.8 mA g−1, and exhibits no obvious capacity decay for 150 cycles at 101.8 mA g−1. The LiMn2O4 cathode material prepared with molten salt assistant could display much better electrochemical performance than the one prepared without molten salt assistance. In particular, it has an initial discharge capacity of 117.5 mAh g−1 at a current density of 0.5C and good rate capability. In the field of lithium ion batteries, both the Mn2O3 anode and LiMn2O4 cathode materials could exhibit enhanced electrochemical performance due to the well formed morphology based on the ionic liquid-assisted solvothermal method.
Advances in our understanding of the etiologies and pathogenesis of Alzheimer's disease (AD) highlight a role for free radical-mediated injury to brain regions from early stages of this illness. Here we will review the evidence from transgenic mouse models of AD, autopsy samples, and human biofluids obtained during life paying particular attention to the stage of disease. In addition, we will review the epidemiologic literature that addresses the potential of anti-oxidants to prevent incident dementia from AD, and the clinical trial literature that addresses anti-oxidant preventative or therapeutic strategies for different stage of AD. Future efforts in preclinical models and ultimately clinical trials are needed to define optimally effective agents and combinations, doses, and timing to suppress safely this facet of AD.
In Wireless Sensor Networks (WSNs), maintaining connectivity with the sink node is a crucial issue to collect data from sensors without any interruption. While sensors are typically deployed in abundance to tolerate possible node failures, a large number of simultaneous node failures within the same region may result in partitioning the network which may disrupt the network operation significantly. Given that WSNs are deployed in inhospitable environments, such node failures are very likely due to storms, fires, floods, etc. The self-recovery of the network from these large-scale node failures is challenging since the nodes will not have any information about the location and span of the damage. In this paper, we first present a distributed partition detection algorithm which quickly makes the sensors aware of the partitioning in the network. This process is led by the sensors whose upstream nodes fail due to damages. Upon partition detection, sensors federate the partitions and restore data communication by utilizing the former routing information stored at each sensor to the sink node and exploiting sensor mobility. Specifically, the locations of failed sensors on former routes are used to assess the span of the damage and some of the sensors are relocated to such locations to re-establish the routes with the sink node. Relocation on such former routes is performed in such a way that the movement overhead on sensors is also minimized. Our proposed approach solely depends on the local information to ensure autonomicity, timeliness and scalability. The effectiveness of the proposed federation approach is validated through realistic simulation experiments and has been shown to provide the mentioned features.
Fluoride doping Li4Ti5O12 nanosheets (F-LTO NSs) are synthesized using a facile hydrothermal reaction, followed by a calcination treatment. It is found that F atoms can enter the lattice structure of spinel LTO NSs without morphology change. Electrochemical test results shows that the fluoride doping of LTO NSs not only increased the electron conductivity of LTO NSs through trivalent titanium (Ti3+) generation, but also increased the robustness of the structure to repeated lithiation and delithiation. The rate performance of LTO NSs has been evidently improved by F doping. At the highest rate of 5 A g−1 (28.6C), F-LTO NSs still display a capacity retention of 101.4 mA h g−1. F-LTO NSs show superior cycling performance with the high reversible capacity at a current density of 2 A g−1 (11.4C), retaining 84.2% of its initial capacity after 1000 cycles with a capacity retention of 116.8 mA h g−1.
The Li3V2(PO4)3/C composite cathode material is synthesized via a simple carbothermal reduction reaction route using polyvinyl alcohol (PVA) as both reduction agent and carbon source. The XRD pattern shows that the as-prepared Li3V2(PO4)3/C composite has a monoclinic structure with space group P21/n. The result of XPS shows the oxidation state of V in the Li3V2(PO4)3/C composite is +3. The Raman spectrum reveals that the coating carbon has a good structure with a low I D/I G ratio. The high-quality carbon can not only enhance the electronic conductivity of the Li3V2(PO4)3/C composite but also prevent the growth of the particle size. The electrochemical performance, which is especially notable for its high-rate performance, is excellent. It delivers an initial discharge capacity of 105.3mAh/g at 5C, which is retained as high as 90% after 2000 cycles. No capacity loss can be observed up to 300 cycles under 20C rate condition. Our experimental results suggest that this compound can be a candidate as cathode materials for the power batteries of hybrid electric vehicles (HEVs) and electric vehicles (EVs) in the future.
A novel strategy is developed to synthesize metal-organic framework (MOF) derived core/shell structured CoP@C polyhedrons anchored on 3D reduced grapheme oxide (RGO) on nickel foam (NF) as binder-free anode for high performance sodium-ion battery, through an in-situ low-temperature phosphidation process from ZIF-67 derived core/shell Co@C polyhedral structures. The unique CoP@C-RGO-NF binder-free anode exhibits a remarkable electrochemical performance with outstanding cycling stability and high rate capability, delivering a specific capacity of 473.1mAhg−1 at a current density of 100mAg−1 after 100 cycles. The excellent properties can be attributed to synergistic effects between core/shell CoP@C polyhedrons and RGO networks. The unique core/shell CoP@C polyhedrons can offer more electrode/electrolyte contact area and reduce the diffusion distance of Na+, while carbon layer shell can enhance electronic conductivity and buffer volume change, and prevent CoP from pulverization and aggregation. Furthermore, 3D RGO networks can provide adequate surface areas for a high loading content of CoP and enhance charge transfer kinetics. Meanwhile, RGO/NF can efficiently act as a binder and electrical conductor to interconnect the separate CoP@C polyhedrons. The present strategy for CoP@C-RGO-NF architectures can be extended to other novel electrodes for high performance energy storage devices.
Gas nitridation has shown excellent promise to form dense, electrically conductive and corrosion-resistant Cr-nitride surface layers on Ni–Cr base alloys for use as proton exchange membrane fuel cell (PEMFC) bipolar plates. Due to the high cost of nickel, Fe-base bipolar plate alloys are needed to meet the cost targets for many PEMFC applications. Unfortunately, nitridation of Fe-base stainless steel alloys typically leads to internal Cr-nitride precipitation rather than the desired protective surface nitride layer formation, due to the high permeability of nitrogen in these alloys. This paper reports the finding that it is possible to form a continuous, protective Cr-nitride (CrN and Cr2N) surface layer through nitridation of Fe-base stainless steel alloys. The key to form a protective Cr-nitride surface layer was found to be the initial formation of oxide during nitridation, which prevented the internal nitridation typically observed for these alloys, and resulted in external Cr-nitride layer formation. The addition of V to the alloy, which resulted in the initial formation of V2O3–Cr2O3, was found to enhance this effect, by making the initially formed oxide more amenable to subsequent nitridation. The Cr-nitride surface layer formed on model V-modified Fe–27Cr alloys exhibited excellent corrosion resistance and low interfacial contact resistance under simulated PEMFC bipolar plate conditions.
Deep brain stimulation (DBS) is a neurosurgical procedure that allows targeted circuit-based neuromodulation and is commonly used for the treatment of movement disorders such as Parkinson disease, tremor and dystonia.Innovations in the field of cardiac pacemakers have enabled pulse generators for DBS to evolve from external devices to small rechargeable, implantable devices.With directional DBS leads, the current can be directed or shaped to personalize stimulation to individual anatomical structures.Closed-loop DBS systems simultaneously record and stimulate neural activity, allowing the stimulation to be adjusted according to disease-specific neural biomarkers.Open-access software can be used to localize DBS electrodes and, on the basis of the stimulation parameters, to model the volume of tissue activated around the electrodes, shedding light on key neurocircuitry elements.As DBS systems become compatible with wireless networks, remote programming by physicians will become possible but privacy issues will also need to be addressed to prevent misuse, including ‘brainjacking’.
Six spinel LiNi0.5Mn1.5O4 (LNMS) samples with different morphologies were synthesized via a PVP (polyvinylpyrrolidone)-assisted gel combustion method by varying the calcination temperature from 800°C to 1050°C. XRD tests were used to characterize the crystal structure and phase purity. SEM images clearly revealed the evolution of the particle size (from sub-micrometer to micrometer), shape and degree of agglomeration with increasing calcination temperature. Charge/discharge tests indicated that the LNMS samples composed of larger primary particles had better cyclic performance than those composed of smaller primary particles. Among the six samples, LNMS1050-6 (calcined at 1050°C) and LNMS1000-6 (calcined at 1000°C) demonstrated excellent capacity retentions of 97.6% and 97.3%, respectively, after 200 cycles with a 1C rate at room temperature. The cyclic performance of LNMS1050-6 and LNMS1000-6 at 55°C was also remarkable, showing capacity retentions of 97.1% and 96.0%, respectively, after 50 cycles at a 1C rate. Rate capability tests indicated that among the six LNMS samples, the single-crystal-like LNMS1000-6 with a moderate particle size (1–3μm) showed the best rate capability. It delivered 132.9mAhg−1, 130.2mAhg−1, 128.1mAhg−1 and 124.5mAhg−1 at rates of 1C, 5C, 10C and 15C, respectively. Electrochemical impedance spectroscopy (EIS) measurements showed that larger primary particles exhibited slower interface impedance increases upon cycling than smaller particles.
When selecting a suitable molten salt electrolyte system for liquid metal batteries (LMBs), it is crucial to have an accurate understanding of the local structures and transport properties of molten salt mixtures. In this study, molecular dynamics simulations have been employed to calculate such properties of (Li, Na, K, Cs)Cl and (Li, K, Rb, Cs)Cl quaternary molten alkali chloride systems at 700–1000 K using the Born–Mayer–Huggins potential. The results show that the density and shear viscosity of the molten salt electrolyte increase when the average cation radius increases, while the self-diffusion coefficient and ionic conductivity decrease. Increasing the temperature in LMBs can enhance the diffusibility and electroconductivity of the molten salt electrolyte and reduce the density and shear viscosity to a certain extent. Overall, the calculated results provide a useful reference for the selection of molten salt electrolytes with reasonable composition to optimize the electrochemical performance of LMBs.