batterydata/paper-abstracts huggingface dataset:
The usage of network-demanding applications is growing rapidly such as video streaming on mobile terminals. However, network and/or service providers might not guarantee the perceived quality for video streaming that demands high packet transmission rate. In order to satisfy the user expectations and to minimize user churn, it is important for network operators to infer the end-user perceived quality in video streaming. Today, the most reliable method to obtain end-user perceived quality is through subjective tests, and the preferred location is the user interface as it is the closest point of application to the end-user. The end-user perceived quality on video streaming is highly influenced by occasional freezes; technically the extraordinary time gaps between two consecutive pictures that are displayed to the user, i.e., high inter-picture time. In this paper, we present a QoE instrumentation for video streaming, VLQoE. We added functionality to the VLC player to record a set of metrics from the user interface, application-level, network-level, and from the available sensors of the device. To the best of our knowledge, VLQoE is the first tool of its kind that can be used in user experiments for video streaming. By using the tool, we present a two state model based on the inter-picture time, for the HTTP- and RTSP-based video streaming via 3.5G. Next, we studied the influence of inter-picture time on the user perceived quality through out a user study. We investigated the minimum user perceived inter-picture time, and the user response time.
We develop an effective strategy to prepare intercalation pseudocapacitor by enlarging interlayer spacing of layered birnessite MnO2 through a controllable intercalation of K+, H+, TMA+/H+, TMA+ cations. The interlayer spacing of K-birnessite is swollen from ∼0.52 nm to 0.77 nm of TMA-birnessite. TMA+/H+ = 1000 sample exhibits an impressively high specific capacitance of 580.05 F g−1, much larger than that of K-birnessite, H-birnessite, TMA+/H+ = 800 (352.8, 414.9, 497.25 F g−1) at current density of 2 A g−1, showing excellent cycling performance with 112% capacitance retention after 10000 cycles. Even upon 20 A g−1, the capacity of TMA+/H+ = 1000 still remains a high level of 503 F g−1, while K-birnessite, H-birnessite, TMA+/H+ = 800 undergo a severe degradation to 180, 216, 433 F g−1. The expanded interlayer spacing enlarges the ion diffusion tunnels, weakens the layer interaction and decreases the resistance of charge diffusion, which easily enables the sufficient utilization of the active material through rapid ion intercalation. More importantly, the molecular-level thickness of host MnO2 layers that expose almost all the active sites on both sides of diffusion tunnels, thus greatly enhances the electrochemical storage capacitance. The results prove the feasibility of this method to prepare new intercalation pseudocapacitor and provide hints for other layered materials.
Objective To investigate whether anodal and cathodal transcranial direct current stimulation (tDCS) can modify cognitive performance and neural activity in healthy elderly and Alzheimer’s disease (AD) patients. Methods Fourteen healthy elderly and twelve AD patients performed a working memory task during an electroencephalogram recording before and after receiving anodal, cathodal, and sham tDCS over the left dorsolateral prefrontal cortex. Behavioural performance, event-related potentials (P200, P300) and evoked cortical oscillations were studied as correlates of working memory. Results Anodal tDCS increased P200 and P300 amplitudes in healthy elderly. Cathodal tDCS increased P200 amplitude and frontal theta activity between 150 and 300 ms in AD patients. Improved working memory after anodal tDCS correlated with increased P300 in healthy elderly. In AD patients, slight tendencies between enhanced working memory and increased P200 after cathodal tDCS were observed. Conclusions Functional neural modulations were promoted by anodal tDCS in healthy elderly and by cathodal tDCS in AD patients. Significance Interaction between tDCS polarity and the neural state (e.g., hyper-excitability exhibited by AD patients) suggests that appropriate tDCS parameters (in terms of tDCS polarity) to induce behavioural improvements should be chosen based on the participant’s characteristics. Future studies using higher sample sizes should confirm and extend the present findings.
First principles calculations have been used to investigate the effect of fluorine substitution on the electrochemical properties of Li2VOSiO4 and LiFePO4. Several models of hypothetical LiVSiO4F and Li0.5FePO3.5F0.5 within the structure of the corresponding parent compounds have been analyzed. The computational results indicate that the lithium insertion voltage is largely controlled by the crystallographic site that fluorine ions occupy in the structure. In some models of LiVSiO4F and Li0.5FePO3.5F0.5 lithium deinsertion causes a too large M–F distance (indicative of MF bond breaking), being the predicted lithium insertion voltage about 0.3V lower than that of the parent compound. In the energetically most stable model of hypotetical-LiVSiO4F the VF bond is retained, and a voltage increasing of 0.5V is predicted with respect to that of the parent compound. For hypothetical Li0.5FePO3.5F0.5 models consisting on FeO6 and FeO4F2 octahedra the lithium deinsertion produces solely the oxidation of Fe2+ surrounded by oxygen ions, which is accompanied by a voltage decreasing. These findings are supported by the computational results on the known intercalation compound LiVPO4F.
Unlike other countries where indigenous people constitute the minority groups, in Indonesia majority of the population (about 95%) are natives (pribumi). There are over 300 ethnic groups in Indonesia who live side by side and in some cases form blurred inter-ethnic boundaries. In addition, Indonesia has unique indigenous Early Childhood Education model that is different from other countries. Indigenous Early Childhood Education in Indonesia is stated in the national laws and government regulations local contents curriculum in education. Local contents defined as educational programs, substances and media transfers, which are related with the natural, social and cultural environments and the needs of regional development being taught to students. The objective of this paper is to describe the implementation Indigenous Early Childhood Education for promoting the physical, intellectual, social, emotional growth of young children aged under three years in Indonesia. The paper also intends to explain the barriers encountered and recommend remedial measures.
Polythiophene (PTh)-based coordination complexes, polythiophene–iron (PTh–Fe) and polythiophene–iron–oxygen (PTh–Fe–O) were synthesized by chemical method and proved to be novel high-performance organometallic lithium-storage materials. Extended X-ray absorption ﬁne structural (EXAFS) spectroscopy and density functional theory (DFT) calculations indicate that these complexes have layered structures. It is believed that the strong and stable Fe–S coordination creates sites of lithium storage and ensures the high specific capacity and outstanding cycle performance of the PTh-based complexes.
Objective To examine the effect of rimonabant on neurocognitive impairments in people with schizophrenia. Methods Participants entered a 16-week double-blind, placebo-controlled, randomized clinical trial. A neurocognitive battery was administered at baseline and end of study. Results In comparison to rimonabant (20mg/day), placebo-treated participants exhibited a significant improvement on the Repeatable Battery for the Assessment of Neuropsychological Status total score. In contrast, rimonabant was associated with significant improvement on a probabilistic learning task. There were no other significant treatment effects. Conclusions Rimonabant did not improve global cognitive functioning, but did improve a specific learning deficit based on response to positive feedback.
Signal detection theory was developed during the Second World War as a means to improve the ability of radar operators to spot enemy bombers. In this article, Oliver et al. explain how an overworked neurologist might use signal detection theory in the clinic to sift out important information from the often bewildering array of visual, verbal and auditory cues that constitute a patient's history and examination.
A Johnson Matthey 287 (JM 287) graphite powder disks sandwiched between two nickel screens was used as working electrodes in 1.0 M lithium hexafluorophosphate in mixed carbonate ester electrolyte. Their intrinsic impedance and lithium intercalation kinetics were determined using several different electrochemical impedance spectroscopy (EIS) protocols. The thermal stability of the electrolyte was similarly studied using a floating palladium wire working electrode. Studies at 25°C and 65°C show that a first high frequency depressed semicircle, a second depressed semicircle, and a sloping line in the low frequency range are respectively related to the initial formation of a solid electrolyte interface (SEI) film, the charge-transfer reaction, and lithium diffusion in graphite. The intrinsic resistance is in series with the reaction impedance and effectively increases the latter. The charge-transfer semicircle at the open-circuit potential moves to the low frequency range, whereas the semicircle associated with the freshly formed SEI film moves to high frequency range as lithium insertion proceeds. The passivating SEI film formed at 25°C slows down co-insertion of the electrolyte into graphite when the electrode is cycled at 65°C, which increases the cycle life of graphite at elevated temperature.
The in-situ stress is a crucial parameter in rock engineering. CSIRO in-situ stress measurements are one of the four suggested direct measurement methods and have been widely used worldwide. With the development of exploration and excavation in deep earth, temperature disturbances during overcoring and the nonlinear behavior of rock under high stress levels increase the error of CSIRO in-situ stress measurements. To satisfy the requirements of in-situ stress measurements in depth, a new local digital wireless CSIRO cell was developed and is introduced in this paper. The twin temperature compensation method is illustrated, and deviations based on several data processing methods are compared as well. The thermal output of a rock-gauge set is discussed, and a series of self-compensating strain gauges are selected for the manufacturing of the CSIRO cell. Two sites for in-situ stress measurements were utilized at the Sanshandao gold mine (795 m deep) and Lilou iron mine (300 m deep). Strains resulting from stress relief are analyzed, and temperature deviations occurring in the sensor system and data logging system are calculated by the twin temperature compensation method. To eliminate the theoretical limitation of the linear behavior assumption, nonlinear relations of the mean stress vs. bulk and shear modulus are proposed for the biaxial pressurization test. A high confining pressure apparatus was developed to reach a similar stress level as deep rock; in addition, associated equations to describe nonlinear features of rock core are deduced. Biaxial testing at high pressure was conducted, and both linear and nonlinear fits were applied to overcoring cores of the Sanshandao and Lilou mines. The results show that the proposed nonlinear method achieves an extremely good approximation and higher precision.
This paper reports a computational demonstration and analysis of an innovative counter-flow-based microfluidic unit and its upscaling network, which is compatible with previously developed dual-electrolyte protocols and numerous other electrochemical applications. This design consists of multidimensional T-shaped microchannels that allow the effective formation of primary and secondary counter-flow patterns, which are beneficial for both high-performance regenerative H2/O2 redox cells and flow batteries at a low electrolyte flow-rate operation. This novel design demonstrates the potential to achieve high overall energy throughput and reactivity because of the full utilization of all available reaction sites. A computational study on energy and pressure loss mechanism during scale-out is also examined, thereby advancing the realization of an economical electrolyte-recycling scheme.
In this paper, homogeneous composites of pomegranate-structured SnO2@C/Cu have been prepared by a simple hydrothermal reaction coupled with wet-chemical reduction, and directly used as anode materials for lithium ion batteries (LIBs). These SnO2@C/Cu anodes with an unique architecture show good LIB performance with a capacity of 660mAhg−1 tested at 600mAg−1 after 50 cycles and good rate performance at room temperature. Compared with the pure SnO2 and SnO2@C, SnO2@C/Cu anodes exhibit much better low-temperature electrochemical performance including reversible capacity, cycling performance, and rate performance. The good LIB performance of SnO2@C/Cu anodes should be associated with carbon shell and the conducting Cu particles. This unique configuration can prevent the agglomeration of active materials and facilitate electron conduction especially at a relative low temperature, and obtain the capacity stability in cycling process for LIBs.
As a promising anode candidate for lithium ion batteries (LIBs), MnO has attracted wide attentions owing to its theoretically high Li-storage capacity, lower working voltage and polarization than other oxides, low cost, environmental friendliness, and abundant resources. Herein, we develop a facile and low-cost strategy to fabricate a unique porous MnO@N-doped carbon (MnO@N-C) nanotube and demonstrate its outstanding Li-storage properties as anode material for LIBs. Benefiting from its unique 1D porous features, the prepared MnO@N-C electrodes exhibit high reversible specific capacity (971.8 mAh g−1 at 0.1 A g−1), superb high-rate capability (359.5 mAh g−1 at 30 A g−1) and remarkable cycling stability (441.5 mA h g−1 after 3500 cycles at 10 A g−1). Such superior electrochemical performance should be due to the high conductivity and protection effects of N-doped carbon layer, and adequate internal voids in the MnO@N-C to effectively accommodate the volume changes of MnO during cycling. In addition, it is also disclosed that the high capacity contribution arises from the pseudocapacitive charge storage.
An effective method of carbothermal reduction was employed to prepare spherical microcrystal NiSn x alloy powders from oxides of Sn and Ni used as anode materials for Li-ion battery. According to XRD, SEM and TEM analysis, the synthesized spherical NiSn x powders show a loose submicro/micro-sized structure and a multi-phase composition. The prepared NiSn x alloy composite electrode exhibits a stable discharge capacity of electrode is ca. 380mAhg−1 at constant current density of 50mAg−1, and can be retained at 350mAhg−1 after 25 cycles. Moreover, NiSn x alloys exhibit excellent high rate performance, i.e. stable discharge capacities of 300–310mAhg−1 and the coulombic efficiencies of 97.5–99.5% have been obtained at the current density of 500mAg−1. The loose submicro-sized particle structural characteristic and the Ni addition in Sn matrix should be responsible for the improvement of cycling stability of NiSn x electrode. The carbothermal reduction method is simple, low-cost and mass-productive, which should be viable to other alloy composite materials system of rechargeable lithium ion batteries.
Products deposited on an O2-cathode discharged in ionic liquid electrolytes are analyzed by transmission soft X-ray microscopy (TXM) and compared to ether-based electrolytes, showing differences in morphology and chemical compositions. With both solvents we observe Li2O2 and LiO2 primary products in similar proportions. However, while as previously observed in tetraglyme an important reactivity takes place producing significant amount of carbonates, in ionic liquid-based electrolytes the formation of carbonates was almost negligible, confirming higher stability. Only when sample is intentionally air exposed before analysis, significant amounts of carbonates came up. However, LiOH crystallites are clearly recognized with the ionic liquid electrolyte. The abundance of these crystallites depends on both the LiTFSI concentration and the storage time of discharged electrodes, suggesting that they result from the reaction of water trace with primary discharge products.
Objective We investigated whether professional air diving with no decompression illness causes any long-term changes in cognitive functions. Methods The all-male participants consisted of 18 healthy control (HC) volunteers and 32 divers. Divers were divided into two subgroups as moderate exposure group, Divers-I (DI) and extensive exposure group, Divers-II (DII). Participants were administered a comprehensive neuropsychological battery and event-related potentials (ERPs) were recorded while they performed auditory oddball task and visual continuous performance test (CPT). Results P3 waves in oddball and CPT were significantly attenuated and peak latencies were prolonged in both diver groups compared with HC. Amplitude decrements in CPT P3 were graded with respect to level of diving exposure. Neuropsychologically, DII group displayed significantly poorer performance than HC and DI groups in measures of visuo-constructional and visual long-term memory tests. DI group performed better than HC group in some measures of planning ability. Conclusions Most of the changes in neurophysiological measures and poorer neuropsychological performance were found in DII group, and this might be interpreted as a red flag for the reflection of the slowly progressing deleterious effects of silent bubbles in brain function. Significance This study reports impairments in certain neuropsychological measures and apparent neurophysiological markers pointing to slow cognitive decline referring to long-term effects of diving.
We present the results of novel type additives to improve the cathode cycleability performance. Benzene derivatives (biphenyl and o-terphenyl) and heterocyclic compounds (furan, thiophene, N-methylpyrrole and 3,4-ethylenedioxythiophene), which have lower oxidation potentials than those of electrolyte solvents are picked up. We use MO calculations in the selection of additives and prove that the calculated HOMO values agree well with the measured oxidation potentials. To clarify the additive performance, electrochemical properties and cycleability of the additive are investigated. The additives are found to be decomposed on cathode to form very thin film. We have named this resulting novel-type thin surface film as electro-conducting membrane (ECM) since it is different from solid electrolyte interphase (SEI) by the point of its electro-conductivity. The nature and the component of ECM are studied with X-ray photoelectron spectroscopy (XPS) and auger electron spectroscopy (AES) in details. It is concluded that these additives, which were formerly known as overcharge protecting proofs, contribute to improve cathode cycleability by forming very thin cathode surface layer in the case of slight amount of addition.
Recent research has focused on the design and sizing of standalone photovoltaic systems. Unfortunately, due to highly fluctuating levels of solar energy and the power supply generated not coinciding with energy demand, high capacity of generation and energy storage systems are required to provide a highly reliable supply. However, a highly reliable system tends to produce high excess energy which needs to be discarded as a dump load, which is proving to be a major concern. For this reason, this paper proposes to use the excess energy for hydrogen production, which will then be sold to local consumers. This paper presents a comparison of optimization design and economic analysis of a standalone photovoltaic with a battery system and a standalone photovoltaic with battery-hydrogen production system using an iterative technique. For the feasibility study of the standalone photovoltaic with a battery and with a hydrogen production system, the proposed minimum hydrogen-selling price is determined by breakeven analysis and is compared to the past references’ hydrogen-selling prices and gasoline prices.
Faster activation of a multi-component AB5 based alloy metal hydride electrode through Pd nanoparticle (NP) impregnation is demonstrated. Pd nanoparticle impregnated MmNi5−x M x based alloy was prepared and characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and elemental mapping techniques. Electro-catalytic activity of laminar metal hydride electrodes containing Pd nanoparticles and micrometer size Ni particles was studied. Hydrogen absorption efficiency of the nanocomposite electrodes was compared with the metal hydride electrodes without Pd nanoparticles. The incorporation of nanostructured materials in the metal hydride alloy increased its hydrogen absorption capacity at the initial stage and activated much faster, indicating its good prospect for energy storage applications.
A second nearest-neighbor modified embedded atom method (2NN MEAM) interatomic potential for lithium–silicon (Li–Si) alloys is developed by using the particle swarm optimization (PSO) method in conjunction with ab initio calculations. It is shown that the new interatomic potential is capable of simulating the transition from disordered to ordered states of Li–Si crystalline structures, an indication of the stability and robustness of the interatomic potential at finite temperature. Examples are given to demonstrate that the new interatomic potential is also capable of predicting the material properties of both crystalline and amorphous Li–Si alloys, including the elastic modulus, compositional expansion, diffusivity of Li in Li–Si alloys, plastic yield strength, etc.
Croconic acid disodium salt (CADS), a renewable or recyclable organic compound, is investigated as an anode material in sodium ion battery for the first time. The pristine micro-sized CADS delivers a high capacity of 246.7 mAh g−1, but it suffers from fast capacity decay during charge/discharge cycles. The detailed investigation reveals that the severe capacity loss is mainly attributed to the pulverization of CADS particles induced by the large volume change during sodiation/desodiation rather than the generally believed dissolution of CADS in the organic electrolyte. Minimizing the particle size can effectively suppress the pulverization, thus improving the cycling stability. Wrapping CADS with graphene oxide by ultrasonic spray pyrolysis can enhance the integration and conductivity of CADS electrodes, thus providing a high capacity of 293 mAh g−1.
Confronting issues of silicon-based anode for its huge volume change (∼320%), porous silicon attracts noteworthy attention. Most previous studies are concentrated on designing various sacrificial templates to endow silicon with marvelous shapes or structures. Herein, without the assistance of sacrificial template, a template-free method is developed to fabricate interpenetrated three-dimensional porous silicon. A silica composite gel, which possesses numerous nano-pores, is primarily constructed, and the silicon can be inherently equipped with these nano-pores via modified magnesiothermic reduction. Scanning electron microscope and transmission electron microscope images illustrate that the as-prepared porous silicon possesses bi-continuous structure. It also exhibits high initial reversible capacity (∼1.41 mAh cm−2 at 0.16 mA cm−2), superior cycling stability (∼0.98 mAh cm−2 after 200 cycles), and good rate performance. In addition, analysis of cyclic voltammetry curves and electrochemical impedance spectroscopy demonstrate that this porous silicon possesses appropriate channels for rapid Li+ transport and low electrochemical reaction polarization resistance.