batterydata/paper-abstracts huggingface dataset:
Li3V2(PO4)3 (LVP) nanoparticles were first prepared via a simple sol-gel route, then deposited on graphene oxide nanosheets, and finally a composite of LVP/reduced graphene oxide (LVP/G) was obtained after heat treatment. Scanning electron microscope and transmission electron microscope images demonstrate that LVP nanoparticles are homogenously enwrapped into graphene nanosheets or anchored onto the surface of graphene nanosheets. Compared with pure LVP, LVP/G nanocomposites exhibited better electrochemical performance (118.4mAhg−1 at 1C, and 112.1mAhg−1 at 2C after 100 cycles) and higher cycling stability (97% capacity retention after 100 cycles at 1C, and 89.5% after 500 cycles at 20C) as cathode materials for Li ion batteries. The enhanced performance can be attributed to the presence of graphene nanosheets among LVP nanoparticles. Electrochemical impedance spectroscopy indicates that graphene nanosheets significantly improve the electrical conductivity of LVP. The as-prepared LVP/G nanocomposites with superior cycling performance at high-rate have potential applications as cathode materials in Li ion batteries.
Individuals with developmental dyslexia are often impaired in their ability to process certain linguistic and even basic non-linguistic auditory signals. Recent investigations report conflicting findings regarding impaired low-level binaural detection mechanisms associated with dyslexia. Binaural impairment has been hypothesized to stem from a general low-level processing disorder for temporally fine sensory stimuli. Here we use a new behavioral paradigm to address this issue. We compared the response times of dyslexic listeners and their matched controls in a tone-in-noise detection task. The tonal signals were either Huggins Pitch (HP), a stimulus requiring binaural processing to elicit a pitch percept, or a pure tone—perceptually similar but physically very different signals. The results showed no difference between the two groups specific to the processing of HP and thus no evidence for a binaural impairment in dyslexia. However, dyslexic subjects exhibited a general difficulty in extracting tonal objects from background noise, manifested by a globally delayed detection speed.
Porous carbide-derived carbons (CDCs) are synthesized from TiC at different chlorination temperatures as electrode materials for electrochemical capacitors. It is found that the microstructure of the produced CDCs has significant influence on both the hydrophilicity in aqueous KOH electrolyte and the resultant electrochemical performance. Because the TiC-CDC synthesized at higher temperature (e.g. 1000 °C) contains well-ordered graphite ribbons, it shows lower hydrophilicity and specific capacitance. It is also found that addition of a small amount of ethanol to KOH electrolyte effectively improves the wettability of the CDCs synthesized at higher temperature and the corresponding specific capacitance. Compared with the CDC synthesized at 600 °C, the CDC synthesized at 1000 °C shows fast ion transport and excellent capacitive behavior in KOH electrolyte with addition of ethanol because of the existences of mesopores and high specific surface area.
In conventional energy harvesting systems, energy can be extracted from a fixed-level source at a constant rate at best. The resulting growth of harvested energy is bound by a linear function. Here we show that exponential energy harvesting can be achieved in a system of reconfigurable energy storage elements. The exponential extraction results from the positive feedback of the system potential energy due to repetitive system reconfigurations. The concept is studied theoretically and validated with results from systems of droplet capacitors. A device with three 300 μL mercury drops can generate an exponentially growing voltage that reaches 168 V within a few cycles of a low-level and low-frequency mechanical excitation. The same device with water drops can generate a similarly growing voltage that reaches 56 V. This concept holds potential in DC power generation and may be applied in other energy domains.
Sodium-ion battery (SIB) is one of the most promising alternatives to partly substitute for lithium-ion batteries (LIBs), yet the large radius of Na+ leads to substantial volume change during sodiation/desodiation processes, resulting in inferior electrochemical performance. Na0.44MnO2 (NMO) possesses S-shaped Na+ diffusion pathway that can accommodate insertion/deinsertion of large Na+, though the poor electronic conductivity of NMO limits its ionic transport kinetics. Herein, single crystalline NMO nanorods (NRs) were synthesized, and their electronic conductivity was enhanced by one order of magnitude using reduced graphene oxide (rGO), as quantified by local conductive atomic force microcopy (c-AFM) measurement. When used as a cathode material for SIBs, NMO/rGO nanocomposite exhibits reversible specific capacities of 124mAh/g at 0.2C after 200 cycles and 70.8mAh/g at 15C, which are significantly enhanced over control cathode made of pure NMO NRs. Through detailed electrochemical impedance spectroscopy (EIS) analysis, it was found that NMO/rGO nanocomposite exhibits much reduced Warburg factor, resulting in enhanced Na+ diffusion at each discharging voltage platform. This suggests that the enhanced electronic conductivity helps Na+ insertion/deinsertion, resulting in improved electrochemical performance, and these insights help us understand how electronic conductivity improves ionic transport kinetics in SIBs.
Nitrogen-doped hierarchical mesoporous/microporous carbon (NMMC) was prepared by synthesizing nitrogen-doped mesoporous titanium-carbide/carbon composite, followed by in situ chlorination of carbides. The NMMC possesses a high surface area (1344m2/g), large pore volumes (0.902cm3/g), narrowed mesopore-size distributions (centered at 4.6nm) and micropores drilled on the mesopore walls with the size of 0.70, 0.97 and 1.61nm. As an electrode material for supercapacitors, the obtained carbon exhibits excellent performance with a reversible specific capacitance as high as 325F/g in 1mol/L H2SO4 aqueous electrolytes contributed by the double-layer capacitance and pseudo-capacitance. The high nitrogen content (7.51 at%) plays an important role in the capacitance enhancement of NMMC, due to the faradaic redox reactions. Meanwhile, the micropores drilled on the mesopore walls can increase the specific surface area to provide more sites for charge storage.
Polypyrrole-coated Bi2O3@CMK-3 nanocomposite is prepared by nanocasting technique and chemical polymerization method. Bi2O3 nanoparticles are dispersed into CMK-3 matrix, and polypyrrole is coated onto the surface of Bi2O3@CMK-3. Polypyrrole-coated Bi2O3@CMK-3 nanocomposite as an anode material for lithium-ion batteries has an outstanding power capability (321mAhg−1 at a current rate of 6Ag−1) and a significantly improved cycling ability (380mAhg−1 after 1000 cycles at a current rate of 5Ag−1). The greatly enhanced electrochemical performance of polypyrrole-coated Bi2O3@CMK-3 nanocomposite is associated with the synergistic effect of highly conductive CMK-3, polypyrrole layer and Bi2O3 nanoparticles. Such a configuration inhibits the aggregation of Bi2O3 nanoparticles and preserves the structure integrity of electrode material, in addition to highly improving the electrical conductivity and maintaining the stable structure of solid electrolyte interface film.
For increasing energy densities of all-solid-state cells, utilizing solid electrolytes in the electrode layer as an active material is useful. Favorable electron conduction paths to the Li3PS4 glass electrolyte were formed by mechanical milling with AB as the conductive additives. The all-solid-state cells with Li3PS4 glass only or mixture prepared by grinding the Li3PS4 glass and AB as a positive electrode did not work. On the other hand, the cell with Li3PS4-AB composite electrodes prepared by milling was successfully charged and then discharged. Initial charge capacity of the cell with the Li3PS4-AB composite electrode was 220 mAh g−1 at 0.064 mA cm−2. Open circuit voltage of the cell was 2.6 V vs. Li, which was higher than that with Li2S active material. In the cell with the Li2S–Li3PS4-AB composite electrode, the Li3PS4 glass functioned as not only Li+ ion conductive paths to Li2S but also active material itself, suggesting that the use of the solid electrolytes as active materials in electrode layers is useful for increasing reversible capacity per gram of a positive electrode.
The dentate gyrus (DG) is a region in the hippocampal formation whose function declines in association with human aging and is therefore considered to be a possible source of age-related memory decline. Causal evidence is needed, however, to show that DG-associated memory decline in otherwise healthy elders can be improved by interventions that enhance DG function. We addressed this issue by first using a high-resolution variant of functional magnetic resonance imaging (fMRI) to map the precise site of age-related DG dysfunction and to develop a cognitive task whose function localized to this anatomical site. Then, in a controlled randomized trial, we applied these tools to study healthy 50–69-year-old subjects who consumed either a high or low cocoa flavanol–containing diet for 3 months. A high-flavanol intervention was found to enhance DG function, as measured by fMRI and by cognitive testing. Our findings establish that DG dysfunction is a driver of age-related cognitive decline and suggest non-pharmacological means for its amelioration.
The present study examines the relative ability of variables from three motivational frameworks to predict four non-linguistic outcomes of language learning. The study examines Action Control Theory with its measures of (1) hesitation, (2) volatility and (3) rumination. The study also examined Pintrich's expectancy-value model that uses measures of (1) intrinsic and (2) extrinsic goal orientation, (3) task value, (4) self-efficacy, (5) control beliefs, and (6) test anxiety. The third motivational framework is Gardner's (1985; 2010) Socio-educational model with its measures of (1) attitudes toward French Canadians, (2) attitudes toward learning French, (3) interest in foreign languages, (4) desire to learn French, (5) motivational intensity, and (6) French class & use anxiety. The four non-linguistic outcomes are (1) perceived communication competence, (2) language anxiety, (2) willingness to communicate, and (4) the intention to continue language study. Participants include 117 high school French-as-a-second-language students (mean age = 16.6 years; 62% female). Regression analyses show that hesitation plays a significant role in predicting perceived communication competence, language anxiety, and willingness to communicate. The intention to continue French studies, however, was best predicated by positive attitudes.
The demand of higher energy density and higher power capacity of lithium (Li)-ion secondary batteries has led to the search for electrode materials whose capacities and performance are better than those available today. Carbon nanotubes (CNTs), with their unique properties such as 1D tubular structure, high electrical and thermal conductivities, and extremely large surface area, have been used as materials to prepare cathodes for Li-ion batteries. The structure and morphology of CNTs were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The functional groups on the purified CNT surface such as –COOH, –OH were characterized by Fourier Transform infrared spectroscopy. The electrode materials were fabricated from LiMn2O4 (LMO), doped spinel LiNi0.5Mn1.5O4, and purified CNTs via solid-state reaction. The structure and morphology of the electrode were characterized using XRD, SEM, and TEM. Finally, the efficiency of the electrode materials using CNTs was evaluated by cyclic voltammetry and electrochemical impedance spectroscopy.
Most methods for treating left-censored data assume the analyte is present but not quantified. Biased estimates may result if the analyte is absent such that the unobserved data represents a mixed exposure distribution with an unknown proportion clustered at zero.
Compared with noble metal catalyst, Co3O4-based electrocatalysts have attracted considerable interesting as low-cost alternatives for oxygen evolution reaction (OER). However, the poor electrocatalytic activity still remains a huge challenge. Herein, we demonstrate a feasible approach through oxidation of CoFe layered double hydroxide (CoFe-LDH) to synthesize Fe-doped Co3O4@C nanoparticles with size of about 30‒50 nm. As OER catalyst, the as-synthesized Fe-doped Co3O4@C nanoparticles exhibited superior OER performance with a small overpotential of 260 mV at the current density of 20 mA cm−2, a small Tafel slope of 70 mV dec−1 and long-term durability (there was no obviously OER current density degradation for 100 h) in alkaline solution. The present work opens a new avenue to the exploration of cost-effective and excellent electrocatalysts based on transition metal oxide materials to substitute precious metal materials for water splitting.
Objective: Nutritional status is an important marker of overall health and linear growth retardation has serious long-term physiological and economic consequences. Approximately 35 and 29% of preschool children in sub-Saharan Africa are stunted and underweight, respectively. There is relatively little information available about the nutritional status in adolescents, the age group with the highest growth velocity after infancy. We conducted a series of cross-sectional surveys to determine the prevalence and main risk groups for malnutrition and to describe the associations between age, sexual maturation and nutritional status in adolescent schoolgirls in western Kenya.
Developing an efficient approach of transforming biomass waste to functional carbon-based electrode materials applied in supercapacitor offers an important and high value-added practical application due to the abundance and considerable low price of biomass wastes. Herein, a hierarchical carbon functionalized with electrochemical-active oxygen-containing groups was fabricated by microwave treatment from the biomass waste of camellia oleifera. The obtained mesoporous carbon (MAC) owns nanosheet morphology, rich mesoporosity, large surface area (1726 m2/g) and very high oxygenic functionalities (16.2 wt%) with pseudocapacitive activity. Prepared electrode of supercapacitor and tested in 2.0 M H2SO4, the MAC exhibits an obvious pseudocapacitive activity and achieved a superior supercapacitive performance to that of directly activated carbon (DAC-800) including high specific capacitance (367 F/g vs. 298 F/g) and better rate performance (66% vs. 44%). The symmetrical supercapacitor based on MAC shows a high capacity of 275 F/g, large energy density of 9.55 Wh/kg (at power density of 478 W/kg) and excellent cycling stability with 99% capacitance retention after 10000 continuous charge-discharge, endowing the obtained MAC a promising functional material for electrochemical energy storage.
This study aimed to examine slow wave activity (SWA), a marker of homeostatic regulation, as a potential mechanism linking sleep disordered breathing (SDB) with executive dysfunction in children.
The current study tested whether an abbreviated version of Defiant Children (Barkley, 1987), an efficacious parent training program to address the behavioral noncompliance often associated with disruptive behavior disorders, could be implemented successfully within a community mental health clinic setting by master's-level therapists. Ethnically and socioeconomically diverse parents of 16 children (ages 4 to 12 years old) completed a 6-session active treatment group emphasizing the use of differential attending skills, effective time-out strategies, and a structured reinforcement schedule to increase child compliance. Pre- and posttreatment measures of attention-deficit/hyperactivity disorder (ADHD), oppositional-defiant disorder (ODD), and conduct disorder (CD) symptom level were administered, as well as a measure tapping the contextual breadth (i.e., number of settings) and severity of disruptive behaviors. Parent satisfaction with the treatment was also assessed. Analyses indicated large treatment effects on all measures except CD behavior. Results are discussed in the context of implementing empirically supported therapies in settings where “treatment as usual” is the norm.
In this study, direct templating method was employed for preparation of mesoporous carbon materials with different pore structure. In order to control pore structure, reaction time of surfactant/silicate which played a role of template was varied. According to increase of reaction time, larger pore size, smaller pore volume, lower pore connectivity and rougher pore surface were observed. From an investigation of supercapacitor performance, it was concluded that higher pore connectivity resulted in more improved rate performance in spite of smaller pore size. Especially, the carbon electrode of 2h reaction time delivered a high capacitance of 102Fg−1 and capacitance per area (13.0μFcm−2), which indicated an efficient utilization of the available pores. Furthermore, the electrode exhibited a low resistance of 2.4Ωcm2, which was comparable to ordered mesoporous carbon electrodes.
A theoretical model to evaluate the thermal performance of an evaporative wind tower installed in open spaces with hot and dry climates has been developed. It was based on the laws of conservation of mass and energy and used TRNSYS as a simulation tool. Evaporative wind towers produce an adiabatic cooling which has been modelled taking into account all the heat and mass exchanges between the airflow and the injected water, and also considering the processes of radiation, convection and conduction. The system analyzed has a special design based on an existing installation placed in Madrid, which is composed of sixteen evaporative wind towers with one fan and six nozzles on the top of each one. A first validation of this theoretical model was done by comparing calculated results obtained through numerical simulation with experimental data. These last data were previously registered in a campaign carried out during the summer 2008 to evaluate the thermal behaviour of the system. To contrast both results, the same initial assumptions in fan and water operation as well as environmental conditions were considered. The comparison between them during the period of 18th to 20th July 2008, show an average temperature drop of 6.5 °C and an average increase of relative humidity of 27%. These values present a high correlation, up to 0.79, between experimental and calculated wet bulb depression. The average cooling power achieved by this system varies from 13 to 16 kW, with maximum peaks around 20 kW. So this theoretical model could be used for future energy estimations of wind towers design with similar constructive characteristics.
Publisher Summary This introductory chapter introduces the relationship between public health and emergency management in the development of the U.S. preparedness infrastructure. The U.S. National Preparedness Guidelines are based on federal, state, and local preparedness capabilities that are generated through the use of 15 National Planning Scenarios. The scenarios are used for training and exercises to identify and assess Universal Tasks and Target Capabilities at each level of the government. This is the structure by which preparedness is developed and evaluated in the United States. However, public officials do not have the capacity to meet the needs arising from major disasters without the assistance of volunteer organizations and the cooperation of the public. A key aspect of public and volunteer engagement is social capital. This interconnectedness of community networks has waned in recent years and to effectively manage a major incident, it needs to be reignited. In addition, citizens must be motivated to take simple measures such as completing a plan, preparing a kit, and following the advice of officials. These steps mitigate the severity of major disasters and sustain the physical and mental health of those affected by catastrophe.
The synthesis, physicochemical properties and conductivity mechanism of a family of ionic liquid-based electrolytes for use in secondary Mg batteries are reported. The electrolytes are obtained by dissolving controlled amounts of δ-MgCl2 salt into the ionic liquid (IL) 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF4) which acts as a solvent. δ-MgCl2 consists of an inorganic ribbon of Mg atoms covalently bonded together through bridging chlorine atoms. Due to this peculiar structural motif, with respect to the electrolytes based on conventional Mg salts, it is possible to achieve electrolytes of higher Mg concentration. Thus, concatenated anionic complexes bridged via halogen atoms are formed, improving the electrochemical performance of these materials. Electrolytes with a general formula EMImBF4/(δ-MgCl2) f with f ranging from 0 to 0.117 are obtained. The composition of the obtained materials is determined by Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES). The properties of these systems are investigated by means of Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), and vibrational spectroscopy in both medium (MIR) and far infrared (FIR). Finally, Broadband Electrical Spectroscopy (BES) is carried out with the aim to elucidate the electrical response of the electrolytes in terms of their polarization and relaxation phenomena and to propose a conductivity mechanism. At 20°C the highest conductivity (0.007S/cm) is observed for the electrolyte with cMg =0.00454molMg/kgIL.
The spatial distribution of Li ions in electrochemically lithiated graphite anodes for Li-ion battery is characterized by scanning Auger electron microscopy. We show that direct mapping of Li KVV peak intensity reveal the spatial distribution of intercalated Li and its chemical state in a quantitative manner. Furthermore, we demonstrate that mapping using a C KVV peak also reflects the spatial distribution of Li due to the change in the electronic properties of C atoms induced by the electrode reaction (Li intercalation). Mapping measurements on three samples with different charging states (20%, 50%, and 100%) show that at the early stage of charging Li ions do not intercalate homogenously into all the graphite particles but selectively into some specific ones with higher rates. Our method provides the criteria to evaluate structure-correlated Li intercalation from nanometer- to micrometer-scale, such as conductivity network in the electrodes due to a non-uniform morphology of binder and conductive additives.