batterydata/paper-abstracts huggingface dataset:
The effect of the surface roughness on the cell-impedance-controlled lithium transport through the Li1−δ CoO2 film electrode was experimentally investigated in a 1M LiClO4-PC solution by the analyses of the potentiostatic current transient (PCT) and the linear sweep voltammogram (LSV). The flat and fractal Li1−δ CoO2 film electrodes were prepared on the Pt/polished Al2O3 substrate and the surface-modified Pt/unpolished Al2O3 substrate, respectively. From the ac-impedance spectra obtained from the flat and fractal electrodes, it is found that the apparent self-similar fractal dimension reduces the charge-transfer resistance. All the PCTs did not exhibit the generalised Cottrell behaviour until the characteristic time t ch and all the power dependence of the peak current on the potential scan rate positively deviated from the generalised Randles–Sevcik behaviour above the characteristic scan rate ν ch in the LSVs. From the analyses of the PCTs and the LSVs in terms of t ch and ν ch, furthermore, it is experimentally confirmed that the surface roughness plays a significant role in the kinetic facilitation of the interfacial charge-transfer reaction during the whole lithium intercalation and deintercalation processes.
A reduced order model (ROM) is proposed for accurate prediction of electrochemical and thermal response of lithium ion cells. The order reduction is carried on the coupled partial differential equations (PDE) of the electrochemical thermal model by consistent volume averaging of local heat generation and spatial temperature variation. The model is validated with experimental data for temperatures ranging from 253 K–333 K. It is seen that modification of ROM to account for low electronic conductivity results in accurate voltage estimation of cells with lithium nickel cobalt aluminium oxide (LNCO) cathodes. A detailed parametric sensitivity to operating conditions is provided. The utility of ROM for on-board state estimation is demonstrated by applying to realistic drive cycle protocols such as the Hybrid Pulse Power Characterization (HPPC) and the Urban Dynamometer Driving Schedule (UDDS) data. The electrochemical structure of ROM enables identification of controlling processes, and analysis of HPPC results reveal that Ohmic drop of cathode is controlling at high rates and the electrolyte potential during rest phase. Based on accurate voltage prediction, computational speed and physical insights, it can be concluded that the proposed ROM is an adequate state estimation and a cell design tool.
Bloodstream infections are responsible for thousands of deaths each year. The rapid identification of the microorganisms causing these infections permits correct therapeutic management that will improve the prognosis of the patient. In an attempt to reduce the time spent on this step, microorganism identification devices have been developed, including the VITEK® 2 system, which is currently used in routine clinical microbiology laboratories.
Nitrogen physisorption was used to analyze textural transformations in lithium-sulfur cathodes during cycling for two alternate electrolyte systems. Significant impact of the electrolyte type on the accessible cathode porosity in the charged vs. discharged state was detected, providing important insights in the cells conversion mechanism and the role of polysulfide solubility. The main advantage of the method lies in the resolution of pore accessibility and size distributions. Thus, depending on the state of charge (SoC), the C-rate used for cycling as well as electrolyte properties (i.e. polysulfide solvation), significant differences in the redistribution of active sulfur species as well as pore blocking effects can be identified. This methodology might facilitate interpretation and further optimization to achieve long-term stable lithium-sulfur batteries.
Hydrogen storage alloys La0.7Mg0.3(Ni0.9Co0.1) x (x =3.0, 3.1, 3.3, 3.4, 3.5, 3.7 and 3.8) were prepared by inductive melting followed by annealing treatment at 1173K for 6h. The effects of the stoichiometry (x) on the structural and electrochemical characteristics of the alloys were investigated systematically. X-ray diffraction (XRD), optical morphology and energy dispersive spectrometry (EDS) analyses showed that these alloys have a multiphase structure which consists of a (La, Mg)Ni3 phase with the PuNi3-type rhombohedral structure, a LaNi5 phase with the CaCu5-type hexagonal structure and a (La, Mg)2Ni7 phase with the Ce2Ni7-type hexagonal structure. The main phase of the alloys with x =3.0 and 3.1 is (La, Mg)Ni3 phase (PuNi3-type structure), the main phase of the alloys with x =3.3, 3.4 and 3.5 is (La, Mg)2Ni7 phase (Ce2Ni7-type structure), and the main phase of the alloys with x =3.7 and 3.8 is LaNi5 phase (CaCu5-type structure). Moreover, the lattice parameters of the (La, Mg)Ni3 phase, (La, Mg)2Ni7 phase and LaNi5 phase decrease monotonously with the increase of the value x. The electrochemical analysis shows that the maximum discharge capacity increases from 356.6mAhg−1 (x =3.0) to 392.1mAhg−1 (x =3.5) and then decreases to 344.1mAhg−1 (x =3.8), and the alloys exhibit good cycling stability. As the discharge current density is 3000mAg−1, the high-rate dischargeability (HRD) increases from 30.1% (x =3.0) to 56.1% (x =3.8). The low temperature dischargeability (LTD) increases from 24.3% (x =3.0) to 58.96% (x =3.7) and then decreases to 48.1% (x =3.8).
Recent technological advances have motivated large-scale deployment of RFID systems. However, a number of critical design issues relating to efficient detection of tags remain unresolved. In this paper, we address three important problems associated with tag detection in RFID systems: (i) accurately detecting RFID tags in the presence of reader interference (reader collision avoidance problem); (ii) eliminating redundant tag reports by multiple readers (optimal tag reporting problem); and (iii) minimizing redundant reports from multiple readers by identifying a minimal set of readers that cover all tags present in the system (optimal tag coverage problem). The underlying difficulties associated with these problems arise from the lack of collision detection mechanisms, the potential inability of RFID readers to relay packets generated by other readers, and severe resource constraints on RFID tags. In this paper we present a randomized, distributed and localized Reader Collision Avoidance (RCA) algorithm and provide detailed probabilistic analysis to establish the accuracy and the efficiency of this algorithm. Then, we prove that the optimal tag coverage problem is NP-hard even with global knowledge of reader and tag locations. We develop a distributed and localized Redundant Reader Elimination (RRE) algorithm, that efficiently identifies redundant readers and avoids redundant reporting by multiple readers. In addition to rigorous analysis of performance and accuracy, we provide results from elaborate simulations for a wide range of system parameters, demonstrating the correctness and efficiency of the proposed algorithms under various scenarios.
LiFePO4 and LiFePO4/Fe2P composites have been produced using raw Fe2O3 materials by mechanical alloying (MA) and subsequent firing at 900°C. The LiFePO4 prepared by firing at 900°C for 30min showed a maximum discharge capacity of 160mAhg−1 at C/20, which is at a higher capacity and improved cell performance compared with the LiFePO4 prepared using for a longer firing times. LiFePO4/Fe2P composites have been synthesized by the reduction reaction of phosphate in excess of carbon. By transmission electron microscopy (TEM) and scanning electron microscopy (SEM) it was determined that the LiFePO4 phase was agglomerated with a primary particle size of 40–50nm around the surface of Fe2P with particle size of 200nm. The electronic conductivity of the LiFePO4/Fe2P composite increased in proportion with the amount that the Fe2P phase and discharge capacity increased during the cycling. The sample containing 8% of Fe2P in LiFePO4/Fe2P composite showed a high discharge capacity and rate capability at high current.
Cubic garnets of composition Li6.75La3Zr1.75Ta0.25O12, Li6.15La3Zr1.75Ta0.25Al0.2O12, and Li6.15La3Zr1.75Ta0.25Ga0.2O12 were prepared from a co-precipitated precursor and consolidated by hot-pressing to a relative density of ∼96–98%. The total Li-ion conductivities at 298K and activation energies (in parentheses) of Li6.75La3Zr1.75Ta0.25O12, Li6.15La3Zr1.75Ta0.25Al0.2O12 and Li6.15La3Zr1.75Ta0.25Ga0.2O12 were 0.87mScm−1 (0.22eV), 0.37mScm−1 (0.30eV) and 0.41mScm−1 (0.27eV), respectively. The above results suggest that cubic stabilizing substitutions outside of the Li-ion sub-lattice are preferable to obtain faster Li-ion conductivity.
With the objective to investigate the role of the insula in recognizing emotion, we performed direct electrical stimulation over the anterior insular cortex during awake surgery while simultaneously delivering an emotional sensitivity task. We registered 18 consecutive patients with brain tumors associated with the insular lobe, who were undergoing tumor resection. An emotional sensitivity task was employed to measure the patients’ ability to recognize emotions from facial expressions before, during, and after awake surgery. Furthermore, we performed voxel-based lesion symptom mapping (VLSM) to identify the association between relevant brain lesions and emotion recognition. When we performed direct electrical stimulation over the anterior insular cortex during awake surgery, the results showed that the ability to recognize anger was significantly enhanced with the presence of anterior insular stimulation (p < 0.05). Comparing the performance in the emotional sensitivity task before and after surgery, the performance in the anger condition became worse (p < 0.01), but became better in the sadness condition after surgery (p < 0.01). In the case of anger recognition, lower scores in the correct response index were associated with lesions involving the left insula in the VLSM study. Direct electrical stimulation over the anterior insular cortex enhanced anger recognition in patients with insular tumors. In contrast, accuracy of anger recognition was significantly reduced, and sadness was improved, when the performance of emotional sensitivity was compared pre- and post-surgery. Our findings suggest that the insular cortex is involved in changes in emotion recognition, including anger and sadness recognition by modulating arousal level that is closely connected with interoception.
Mental fatigue, with decreased concentration capacity, is common in neuroinflammatory and neurodegenerative diseases, often appearing prior to other major mental or physical neurological symptoms. Mental fatigue also makes rehabilitation more difficult after a stroke, brain trauma, meningitis or encephalitis. As increased levels of proinflammatory cytokines are reported in these disorders, we wanted to explore whether or not proinflammatory cytokines could induce mental fatigue, and if so, by what mechanisms.
This study proposed a painted flexible piezoelectric device (FPED) for harvesting wave energy. The painted FPED had a laminated structure consisting of an elastic material and a piezoelectric paint. The device could be easily deformed by an external force such as wind, wave, current, or mechanical vibration, and it could generate electrical power from an ambient, non-utilised energy source. The results revealed the mechanical deformation and electrical performance of the painted FPED excited by wave conditions. They also clarified the influence of some key parameters, such as the submerged depth, wave steepness, aspect ratio, actuator pattern (unimorph and bimorph), and thickness of the painted piezo-material and elastomer on the output voltage generated by a painted FPED excited by various wave forces, heights and periods. Moreover, a theoretical model was proposed, and the results were in good agreement with the experimental results under several wave conditions. The electrical power in real sea states was estimated by the theoretical model. The electric power could be stored in batteries, and both the monitoring sensors and ocean environmental devices could be triggered and activated to work for practical applications in real sea states.
TiO2 nanocones (TiO2-NCs) are constructed into arrayed spherical shells through a liquid-phase deposition reaction with polymer template, to improve the performance of TiO2 as anode of lithium ion microbattery. The morphology and structure characterizations indicate that TiO2 grows into nanocones with exposed {001} facets and is self-assembled into mesoporous structure. Meanwhile, macroporous channels are formed among the arrayed shells. Electrochemical measurements demonstrate that the TiO2-NCs reveal excellent performance in terms of improved lithium storage property and rate capability. The improved performance can be ascribed to the channel structure for the convenience of ionic transportation and the high-energy facets for the improvement of ionic reactivity.
The current study examined the persistence and phenotypic presentation of inattention/overactivity (I/O) into early adolescence, in a sample of institution reared (IR) children adopted from Romania before the age of 43 months. Total sample comprised 144 IR and 21 non-IR Romanian adoptees, and a comparison group of 52 within-UK adoptees, assessed at ages 6 and 11 years. I/O was rated using Rutter Scales completed by parents and teachers. I/O continued to be strongly associated with institutional deprivation, with continuities between ages 6 and 11 outcomes. There were higher rates of deprivation-related I/O in boys than girls, and I/O was strongly associated with conduct problems, disinhibited attachment and executive function but not IQ more generally, independently of gender. Deprivation-related I/O shares many common features with ADHD, despite its different etiology and putative developmental mechanisms. I/O is a persistent domain of impairment following early institutional deprivation of 6 months or more, suggesting there may be a possible pathway to impairment through some form of neuro-developmental programming during critical periods of early development.
Carbon dioxide (CO2) as a greenhouse gas causes globe warming. Recent studies have shown that CO2 can be harnessed to make an energy storage device through the operation of metal-CO2 batteries. While the Li-CO2 and Na-CO2 batteries showing high capacity and good cycle life have been demonstrated, the possibility of creating a K-CO2 battery has not been realized. Here we report the creation of a K-CO2 battery by using CO2 as the cathode in an advanced aberration corrected environmental transmission electron microscope, and in-situ observation of the discharge and charge processes of the nanobattery. During discharge, K2CO3 was generated in the cathode, which converted back to metal K during charge, and the K-CO2 nanobattery demonstrates a good cyclability. Moreover, it is evident that CO gas was released during discharge and the carbon cathode was consumed continuously during charge. Our study provides a fundamental understanding of the K-CO2 battery, which may aid the designing of K-CO2 based energy storage devices.
This paper aims to study the relationship between questioning and the quality of knowledge constructed in a CSCL context. In previous studies, different units of analysis are employed and the patterns of relationships are not consistent for different age groups. The analytic units of a thread, an individual, and a group are employed in this study, and two grades of students (grade 6 and grade 10) are investigated. At the thread level, we aim to examine to what extent questioning can be a mechanism for knowledge advancement, and we find that the tenth-graders are capable to advance knowledge through questioning, while for the sixth-graders, more facilitation seems to be needed. At the individual level, we find that for the sixth-graders, those asking good questions are likely to express high-level explanations, suggesting that individual competence plays an important role in advancing knowledge among these younger students. For the tenth-graders, a “division of labor” is observed that good questions are generated by some students while high-level explanations by others. At the group level, a high and positive correlation is found for both grades. The findings suggest further research is needed to examine other possible mechanisms for knowledge advancement in online collaborative discourse.
In addition to lattice doping and carbon-coating, surface modification with other metal oxides can also improve the electrochemical performance of LiFePO4 powders. In this work, highly conductive vanadium oxide (V2O3) is in situ produced during the synthesis of carbon-coated LiFePO4 (LiFePO4/C) powders by a solid state reaction process and acts as a surface modifier. The structures and compositions of LiFePO4/C samples containing 0–10mol% vanadium are analyzed by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy. Their electrochemical properties are also characterized with galvanostatic cell cycling and cyclic voltammetry. It is found that vanadium is present in the form of V2O3 that is incorporated in the carbon phase. The vanadium-modified LiFePO4/C samples show improved rate capability and low-temperature performance. Their apparent lithium diffusion coefficient is in the range of 10−12 to 10−10 cm2 s−1 depending on the vanadium content. Among the investigated samples, the one with 5mol% vanadium exhibits the best electrochemical performance.
A novel porous N-doped carbon microsphere (polymer-dopamine derived carbon, PDA-C) with high specific surface area was synthesized as sulfur host for high performance of lithium-sulfur batteries. We used KOH to adjust the pore size and surface area of the PDA-C materials, and then impregnated sulfur into the PDA-C samples by vapor-melting diffusion method. Effects of pore size of the PDA-C samples on the electrochemical performance of the PDA-C@sulfur cathodes were systematically investigated. Raman spectra indicated an enhanced trend of the degree of graphitization of the PDA-C samples with increasing calcination temperature. The surface area of the PDA-C samples increases with amount of the KOH in the pore-creating process. The graphitized porous N-doped carbon provides the high electronic conductive network. Meanwhile, the PDA-C with high surface area and uniform micropores ensures a high interaction toward sulfur as well as the high dispersion of nanoscale sulfur layer on it. The microporous PDA-C@S cathode material exhibits the excellent high rate discharge capability (636mAhg−1 at 2.0C) and good low/high-rate cycling stability (893mAhg−1 (0.5C) and 608mAhg−1 (2.0C) over 100 and 300 cycles). Cyclic voltammogram curves and electrochemical impedance plots show that both the impedance and polarization of the cells increase with decreasing pore size.
Persistent allergic rhinitis (PAR) is characterized by a chronic, eosinophilic inflammation with nasal congestion and rhinorrhea. Nasal congestion can constitute to sleep-disordered breathing problems that range from simple snoring to obstructive sleep apnea syndrome (OSAS). The purpose of this study was to investigate the effect of PAR on sleep quality and severity of OSAS.
When submitted to square-wave potentials of ±2V, single-walled carbon nanotube films with an ionic liquid, taking part of an actuator, show high-frequency electromechanical responses (up to 100Hz), with anodic current evolutions showing two maxima. Similar anodic chronoamperometric responses have been obtained from films of conducting polymers exchanging balancing anions with the electrolyte during reaction, being described by two stretched exponential functions deduced on physico-chemical bases: oxidation under nucleation–relaxation structural control and oxidation/swelling completion under diffusion control. Now by adding a third stretched function, describing a greater contribution now of the charge of the electrical double layer, a good mathematical fit of the chronoamperometric response of the carbon nanotube films was carried out. By recovering the original physico-chemical meaning of the electrochemical stretched functions, capacitive and structural faradic components of the chronoamperometric charge were quantified as a function of the applied frequency (1–10Hz). The capacitive component of the charge ranges with frequency between 8.6% and 12.2% of the involved charge. The faradic (reactive) component ranges between 91.4% and 87.8%, being the main contributor to the volume variations in the actuating films. The order of magnitude of the diffusion coefficients was 10−6 cm2 s−1, in good agreement with the fast response of the reactive actuators constructed with those materials. A good separation of capacitive and faradic components will allow a better design of electrochemical applications of single-walled carbon nanotube films.
This work attempts to bridge laboratory and real-life battery testing data with a comprehensive analysis to provide a coherent approach for a realistic model to simulate battery performance, including life prediction. From electric vehicle field-testing results, we explain how to handle real-life data through driving cycle analysis to establish a scheme of “building blocks” that can be validated by test results obtained in the laboratory. We also show that a simple battery model can be built upon laboratory test data and validated by real-life duty cycles, therefore deriving a more realistic understanding and prediction of battery performance.
In the first experimental study of epilepsy-based discrimination in the workplace, we examined the influence of stigmatization on the workplace outcomes of hypothetical employees who were associated with epilepsy, but who did not have epilepsy themselves (stigma by association). Participants (40 women, 16 men), acting as employers, evaluated one of six randomly assigned employee work portfolios that were identical except that the employee was either male or female and had taken leave during the past year to care for a child with either epilepsy or asthma, or for whom no leave was mentioned. They then evaluated the employee and made recommendations concerning the employee’s workplace rewards (promotion, raise) and penalties (job termination). Work quality evaluation was similar across conditions. However, parents of a child with epilepsy received fewer workplace rewards and greater workplace penalties than did employees in the other conditions. Implications for mental health and antibias interventions are discussed.
A flexible, large-area three-dimensional porous N-doped carbon microtube (NCMT) sponge was prepared via a simple and low-cost process of pyrolyzing facial cotton. Due to its unique structure with a micron-scale hollow core and well-graphitized and interconnected porous walls, the NCMT sponge exhibits incomparable electrocatalytic activity for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER) with a small potential difference of 0.63 V between the OER current density at 10 mA cm−2 and the ORR current density at −3 mA cm−2, which is the best to date.
Fullerene-activated carbon composite electrodes were prepared and their charge/discharge characteristics were studied for use in a high power electric double-layer capacitor. The capacitance of the C60-loaded activated carbon fiber (ACF) electrodes became greater than that of the unloaded ACF at charge/discharge current densities above 50mA/cm2. In order to obtain a highly dispersed C60-loaded electrode, an ultrasonic treatment was performed. The size of the C60 agglomerate decreased from 1–2 to 0.1μm or less, and the capacitance of the C60-loaded ACF electrodes increased with an increase in the ultrasonic treatment time. A higher capacitance of 172F/g was obtained at 50mA/cm2 on a 1wt% C60-loaded electrode with ultrasonic treatment, and the C60-loaded ACF electrode also showed a higher cycle performance.