batterydata/paper-abstracts huggingface dataset:
Thermal runaway hazards related to adiabatic runaway reactions in various 18650 Li-ion batteries were studied in an adiabatic calorimeter with vent sizing package 2 (VSP2). We selected two cathode types, LiCoO2 and Li(Ni1/3Co1/3Mn1/3)O2, and tested Li-ion batteries to determine the thermal runaway features. The charged 18650 Li-ion batteries were tested to evaluate the thermal hazard characteristics, such as the initial exothermic temperature (T 0), self-heating rate (dT/dt), pressure rise rate (dP/dt), pressure–temperature profiles, maximum temperature (T max) and pressure (P max), which are measured by VSP2 with a customized stainless steel test can. The thermal reaction behaviors of the Li-ion battery packs were shown to be an important safety concern for energy storage systems for power supply applications. The thermal abuse trials of the adiabatic calorimetry methodology used to classify the self-reactive ratings of the various cathodes for Li-ion batteries provided the safety design considerations.
Neurological illnesses, including cognitive impairment, memory decline and dementia, affect over 50 million people worldwide, imposing a substantial burden on individuals and society. These disorders arise from a combination of genetic, environmental and experiential factors, with the latter two factors having the greatest impact during sensitive periods in development. In this Review, we focus on the contribution of adverse early-life experiences to aberrant brain maturation, which might underlie vulnerability to cognitive brain disorders. Specifically, we draw on recent robust discoveries from diverse disciplines, encompassing human studies and experimental models. These discoveries suggest that early-life adversity, especially in the perinatal period, influences the maturation of brain circuits involved in cognition. Importantly, new findings suggest that fragmented and unpredictable environmental and parental signals comprise a novel potent type of adversity, which contributes to subsequent vulnerabilities to cognitive illnesses via mechanisms involving disordered maturation of brain ‘wiring’.
In the present paper, we address brain–behaviour relationships in children with acquired aphasia, by reviewing some recent studies on the effects of focal brain lesions on language development. Timing of the lesion, in terms of its occurrence, before or after the onset of speech and language acquisition, may be a major factor determining language outcome. However, it is still unclear which are the effects of aphasia occurring between 2 and 5years of age, a time window which is crucial for acquiring and automatizing the basic rules of native language. A comprehensive review of the literature on acquired childhood aphasia precedes the description of long-term follow-up (20years) of two identical twins, one of whom became aphasic at 3years and 4months after infarction of the left sylvian artery. Psycholinguistic analysis and fMRI data show a slow and incomplete recovery from non-fluent aphasia associated to an intra-hemispheric organization of language. These data, which support the potential but also the limits of neural plasticity during language development, are discussed in the light of the literature on the time-course and neural bases of acquired childhood aphasia.
Instructors often try out innovative interventions (INTRs) in their classrooms to promote student engagement and learning interest. While such efforts are commendable, thinking through how individual and environmental characteristics influence interest development in learners is crucial to meeting such teaching objectives. In this study, we examined the role of personal interest, students’ perceptions of meaningfulness (MNG) and the instructional utility of an innovative hands-on learning module in the development of triggered and maintained situational interests in an engineering classroom that used hands-on learning modules. Participants were undergraduate students enrolled in an engineering classroom who were taught fluid mechanics concepts using an innovative instructional approach. Results of the study indicate that the instructional INTR and the MNG learning material were significant predictors of situational interest. Theoretical and practical implications of the findings are discussed.
Alkali metal anodes (Li, Na, K) are highly promising for enabling high-energy-density rechargeable batteries due to their high theoretical capacities and low redox potentials. Although extensive studies have been performed on Li-metal, dendrite growth and serious interface issues are still fundamental challenges for practical alkali metal batteries (AMBs). Here, we report an in situ-formed graphite intercalation compound (GIC) framework that enables Na–K liquid alloy to be used in ultra-stable and high-capacity anodes, attributed to the synergy of fast electron and mass transport of the GIC networks associated with the self-healing behavior of the Na–K alloy. The Na–K composite electrode is highly stable; it sustains repeated stripping/deposition over 5000 hours at 20 mA cm−2 and achieves stable electrodeposition even at 80 mA cm−2 and 16 mA h cm−2. When coupled with various cathodes, versatile AMBs are realized with long cycling and high operating voltages. This framework electrode design presents new insight into developing dendrite-free alkali metal anodes.
In this paper, we compared the electrochemical performances of ordered MnO2-Graphene (MnO2-GO) oxide with the disordered system of the same composite. The ordered system is fabricated using electrospinning while the disordered system is fabricated dropcasting the same precursor under similar synthesis condition. This fiber-like ordered structure exhibits excellent electrochemical properties both in terms of specific capacitance and cyclic stability because of excellent connectivity between the individual nanoparticles. The electrospun sample having MnO2: GO = 5:2 (by weight) demonstrates the highest specific capacitance of 892.8 F g−1 whereas the disordered sample having same ratio of MnO2 and GO demonstrates 546.9 F g−1 at 2 mV s−1. To correlate the superior electrochemical performance of the ordered sample compared to the disordered one, room temperature dielectric measurements are performed which reveals various parameters like conductivity; diffusivity and mobility of charge carriers. An asymmetric supercapacitor device is fabricated using the fiber-like ordered structure as an active electrode. The device offers maximum power density of 2.8 kW kg−1 and maximum energy density of 96.75 Wh kg−1 with a 93.3% retention after 5000 GCD cycles.
Despite the fact that cognitive impairment rated with clinical rating scales has been shown to be a poor proxy for cognitive functioning measured with a performance-based assessment battery, studies are still using this approach to predict aspects of outcome in schizophrenia. In the current study 106 outpatients with chronic schizophrenia who had been stable both from a symptomatic and a medication perspective for a period of 6 months before study inclusion were investigated to assess the relationship between a clinical rating of cognitive impairment and the actual performance on neuropsychological tests. The cognitive component of the PANSS was compared to results from a neuropsychological test battery which was selected to cover domains known to be impaired in patients with schizophrenia. Correlations of the cognitive component of the PANSS with the individual neuropsychological tests were low. They ranged between 0.19 and 0.35. None of them was sufficiently high to indicate that the cognitive component of the PANSS adequately covers the cognitive dimension measured by the respective neuropsychological test. These data clearly show that clinical assessment of cognitive deficits by the PANSS is not a viable alternative to neuropsychological testing to obtain information about cognitive functioning in schizophrenia.
An intrinsically polar molybdenum disulfide/graphitic carbon nitride porous nanosheets (MoS2/g-C3N4) has been designed as the sulfur host to improve the performance of lithium-sulfur (Li–S) batteries. The strong chemical interaction of lithium polysulfides with MoS2 and nitrogen rich g-C3N4 restrict the shuttling effect of polysulfides, showing stable cycling and excellent rate performance of Li–S batteries by delivering a specific capacity of 430mAh/g after 400 cycles at 8C rate with a low capacity-fading rate of 0.028% per cycle. For the cathode with high areal loading of 4.3 mg/cm2, it gives a very good capacity retention with a decay rate of 0.070% per cycle after 500 cycles at 0.5C. The dramatic improvement in lithium-ion diffusion is responsible for the high rate capability. The cells also exhibit an effective suppression of self-discharge. They deliver a specific discharge capacity retention of 93.60% and maintain cycling stability for 500 cycles at 1C with 0.08% per cycle decay rate after 10 days of resting. The results demonstrate that integration of both physical entrapment and chemical interaction with polysulfides could be an effective strategy for developing high performance Li–S batteries.
LaNiO3 coatings on nickel-foam supports were prepared by brush painting. The electrochemical properties were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Comparative studies were performed with LaNiO3-pelleted electrodes. The roughness factors were determined by CV and found to be 5,208 ± 350 and 4,037 ± 250 for the pelleted and coated electrodes, respectively. EIS measurements confirm the results obtained by CV. Values lower than 0.3 were calculated for the morphology factors for both electrodes, indicating low electrochemical porosity. The experimental method used in this work to synthesise the oxide coupled with the use of Ni foam as support has proved to be very effective in producing oxide electrodes with surface areas higher than those referred to in relevant literature.
This study tested the hypothesis that the cognitive antecedents of word recognition are uniquely domain-specific and unrelated to higher-order domain-general cognitive abilities. This hypothesis was evaluated in a longitudinal study of 349 Hebrew-speaking children (mean age: 6.0 years) who were tested on a battery of domain-specific (phonological awareness, phonological memory, visual-orthographic processing, and early literacy) and domain-general tasks (general intelligence, higher-order reasoning, and language) at the end of kindergarten. Word recognition and reading comprehension were assessed at the end of Grade 1. Whereas the kindergarten domain-specific measures accounted for significant and substantial variance in word recognition (33%), the domain-general measures explained only 5% of the variance. Furthermore, the contribution of domain-specific variables to word recognition remained unaltered even after controlling for all domain-general and higher-order language tasks. Reading comprehension, in contrast, was predicted by both print-specific skills (51%) and domain-general abilities (44%). These findings strongly support the notion of word recognition modularity in a well-encapsulated orthography.
Application of in situ Mössbauer spectroscopy for studying catalysts and catalytic processes is discussed. Examples are presented to illustrate the potentials of the method by describing studies on supported heterogeneous catalysts performed with 119Sn and 57Fe spectroscopies in cases with certain metals and alloys, oxides and porous substances. The results are interpreted in comparison to the catalytic performance.
Here we report the preparation of LiFePO4 cathode for lithium ion battery in the aqueous solvent with polyacrylic acid (PAA) as a binder. Its performances were studied by cyclic voltammetry (CV), charge–discharge cycle test, electrochemical impedance spectroscopy (EIS), X-ray diffraction (XRD), and scanning electron microscopy (SEM), and compared with the cathode prepared in N-methyl-2-pyrrolidone (NMP) solvent by using polyvinylidene fluoride (PVDF) as a binder. It is found that the cathode prepared in the aqueous solvent shows better performances than that in NMP solvent, including the better reversibility, the smaller resistances of solid electrolyte interphase and charge exchange, the less polarization, higher capacity and cyclic stability for lithium ion intercalation in or de-intercalation from LiFePO4. The aqueous solvent is also more environmental friendly and cheaper than NNP. In addition, PAA is less costly than PVDF. Consequently, the preparation of LiFePO4 cathode in the aqueous solvent by using a PAA binder provides lithium ion battery with improved performances at a less cost and in a more environmental friendly way.
From 2002 to 2007, more than 400,000 photovoltaic (PV) solar home systems (SHS) were sold in northwestern China under the US$316 million World Bank/Global Environment Facility-supported Renewable Energy Development Project (REDP). REDP has been hailed as a best practice example in SHS deployment for its unprecedented scale and the combination of technology improvement and market development support components to strengthen the country’s renewable energy industry. While the World Bank has itself conducted post-project evaluations, our paper presents the first independent review with the intent of determining if anticipated project impacts have been sustained. We adopt a case study format supported by in-depth interviews with the project’s relevant stakeholder groups and find that solar home systems (SHS) provide monetary and non-monetary benefits to users and that their portability complements the lifestyle of the region’s nomadic herders. However, we also find that purchasing decisions are still based on price more than quality, after-sales service networks remain weak, and households in REDP’s coverage area are gradually gaining access to hydropower-based grid electricity.
This article reviews the use of micro-organisms as catalysts at the electrodes of microbial fuel cells (MFCs). The principle of MFCs and their intended use for water treatment and clean electricity production is discussed. We address the different microbial structure and metabolic pathways found in prokaryote (bacteria) and eukaryote (yeasts) that allow the understanding of why electron transfer is possible between a microbe and an electrode. The different mechanisms of microbe–electrode electron transfer are discussed: direct electron transfer or through natural nanowires (pili), mediated electron transfer by natural or artificial redox mediator and finally direct redox transformation of excreted metabolites at the electrodes. This is followed by a review of the different bacteria that have been found and studied in MFCs mainly in the anodic compartment but also more recently in the cathodic side of the fuel cells. A perspective on the possible advantages and challenges of the use of yeasts in MFCs is provided, as this aspect has not been thoroughly studied so far. The fourth section of the review focuses on how to improve the performance and sustainability of MFCs through the functionalisation of the electrode surface, for instance with the covalent grafting of redox mediators and/or enzymes.
Globally there is profuse literature on the continuous developments of box type solar cookers and solar ovens. A lot of research work has been carried out in recent passed years in the world which clearly shown the utilization of solar energy towards the greatest needs of mankind obviously solar cooking, fuel saving, non-polluting environment and to save and produce electricity. In the present literature the efforts have been made to focus on diverse developments of box type solar cooker till now. An attempt has been made to optimize the various major parameters such as geometries of box-cooker, glazing system, cooking vessels design, heat storage, insulation, mirror boosters and financial feasibility of solar cooker box. All the discussed factors have been taken into account in the fabrication of a simple solar box cooker and a good improvement has been found in the performance of box cooker with efficient working in low ambient temperatures. A wiper type mechanism to remove vapor droplets from the bottom of glazing, during the cooking process has been introduced and discussed with a new designed cooking vessel. The investigational testing of the fabricated box cooker has been carried out under the climate conditions of Moradabad (latitude – 28°58′north and longitude – 78°47′east) Uttar Pradesh.
The challenge of increasing low-temperature performances of anodes for Li-ion batteries is faced by preparing graphite–tin composite electrodes. The anodes are prepared by mixing partially oxidized graphite with nanometric Sn powder or by coating the oxidized graphite electrode with a thin Sn layer. Long-term cycling stability and intercalation/deintercalation performances of the composite anodes in the temperature range 20°C to −30°C are evaluated. Kinetics is investigated by cyclic voltammetry and electrochemical impedance spectroscopy, in the attempt to explain the role of Sn in reducing the overall electrode polarization at low temperature. Two possible mechanisms of action for bulk metal powder and surface metal layer are proposed.
Operating a passive direct methanol fuel cell (DMFC) with high methanol concentration is desired because this increases the energy density of the fuel cell system and hence results in a longer runtime. However, the increase in methanol concentration is limited by the adverse effect of methanol crossover in the conventional design. To overcome this problem, we propose a new self-regulated passive fuel-feed system that not only enables the passive DMFC to operate with high-concentration methanol solution without serious methanol crossover, but also allows a self-regulation of the feed rate of methanol solution in response to discharging current. The experimental results showed that with this fuel-feed system, the fuel cell fed with high methanol concentration of 12.0M yielded the same performance as that of the conventional DMFC running with 4.0M methanol solution. Moreover, as a result of the increased energy density, the runtime of the cell with this new system was as long as 10.1h, doubling that of the conventional design (4.4h) at a given fuel tank volume. It was also demonstrated that this passive fuel-feed system could successfully self-regulate the fuel-feed rate in response to the change in discharging currents.
Lithium-ion hybrid supercapacitor emerges as a promising candidate to bridge the performance gap between lithium ion batteries and supercapacitors. However, for current lithium-ion hybrid supercapacitor systems, high energy storage is usually accompanied with the sacrifice of high power density due to the mismatched kinetics between the sluggish lithium intercalation in anode and the rapid ion adsorption/desorption at cathode. In this work, we design a simple and controllable synthesis of holey carbon nanolayers with targeted porosity as both anode and cathode to achieve rapid electrochemical kinetics in lithium-ion hybrid supercapacitors. The mesoporous structure, enlarged interlayer spacing and excellent electrical conductivity of anode ensure greatly mitigated lithium diffusion. Simultaneously, the hierarchical porous texture and large external active surface area of cathode contribute to an outstanding capacity of 140 mAh g−1 and better rate capability. The lithium-ion hybrid supercapacitor based on holey carbon nanolayers shows a high energy density up to 181 Wh kg−1, and still preserves a remarkable energy density of 114 Wh kg−1 even at an ultra-high power density of 65 kW kg−1. This work illustrates the pertinence of porosity and morphology manipulation as a competitive strategy for rational fabrication of lithium-ion hybrid supercapacitor electrodes with high power density.
Double doped spinel LiCoxNiyMn2−x−yO4 (x = y = 0.25) have been synthesised via sol–gel method using different chelating agents viz., acetic acid, maleic acid and oxalic acid to obtain 5 V positive electrode material for use in lithium rechargeable batteries. The sol–gel route endows lower processing temperature, lesser synthesis time, high purity, better homogeneity, good control of particle size and surface morphology. Physical characterizations of the synthesized powder were carried out using thermo-gravimetric and differential thermal analysis (TG/DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The electrochemical behaviour of the calcined samples has been carried out by galvanostatic charge/discharge cycling studies in the voltage range 3–5 V. The XRD patterns reveal crystalline single-phase spinel product. SEM photographs indicate micron sized particles with good agglomeration. The charge–discharge studies show LiCo0.25Ni0.25Mn1.5O4 synthesized using oxalic acid to be as a promising cathode material as compared to other two chelating agents and delivers average discharge capacity of 110 mA h g−1 with low capacity fade of 0.2 mA h g−1 per cycle over the investigated 15 cycles.
Carbon nanomaterials are receiving worldwide attention because of their multi-faceted superiority in thermal conductivity, flame retardancy, mechanical stability, electrical conductivity, and biocompatibility. In this review, a survey of the literature on extending performance of epoxy resins based on carbon nanomaterials is presented. The structure-performance relationships for different carbon nanomaterials modified epoxy are closely analyzed. The performance extension in mechanical, electrical, thermal conductivity, flame retardancy, antidegradation, and tribological properties of epoxy are reviewed in detail. Other application areas including biocompatibility, biodegradability, gas barrier properties, shape memory, and electromagnetic interference shielding are touched. The challenges and opportunities in carbon nanomaterials functionalized epoxy composites are also discussed.
One-dimensional (1D) nanostructures of vanadium- and iron-doped manganese oxides, Mn1−x M x O2 (M=V and Fe), are synthesized via one-pot hydrothermal reactions. The results of X-ray diffraction studies and electron microscopic analyses demonstrate that all the present 1D nanostructured materials possess α-MnO2-type structure. While the vanadium dopants produce 1D nanorods with a smaller aspect ratio of ∼3–5, iron dopants produce 1D nanowires with a high aspect ratio of >20. X-ray absorption spectroscopy clearly shows that the dopant vanadium ions are stabilized in tetravalent oxidation state with distorted octahedral symmetry, while the iron ions are stabilized in trivalent oxidation state with regular octahedral symmetry. Significant local structural distortion and size mismatch of dopant vanadium ions are responsible for the low aspect ratio of the vanadium-doped nanorods through the less effective growth of a 1D nanostructure. According to electrochemical measurements, doping with Fe and V can improve the electrode performance of 1D nanostructured manganate and such a positive effect is much more prominent for the iron dopant. The present study clearly indicates that doping with Fe and V provides an effective way of tailoring the crystal dimension and electrochemical properties of 1D nanostructured manganese oxides.
In the last years, the opinion summarization task has gained much importance because of the large amount of online information and the increasing interest in learning the user evaluation about products, services, companies, and people. Although there are many works in this area, there is room for improvement, as the results are far from ideal. In this paper, we present our investigations to generate extractive and abstractive summaries of opinions. We study some well-known methods in the area and compare them. Besides using these methods, we also develop new methods that consider the main advantages of the ones before. We evaluate them according to three traditional summarization evaluation measures: informativeness, linguistic quality, and utility of the summary. We show that we produce interesting results and that our methods outperform some methods from literature.