batterydata/paper-abstracts huggingface dataset:
The spinel Li4Ti5O12 has been doped by Na for the purpose of improving its cycle performance as an anode. The lattice parameter of Li4Ti5O12 increases due to the Na doping. SEM shows that all materials are well crystallized with a particle size in the range of 400–600 nm. The pristine Li4Ti5O12 sample has a bigger particle size than that of Na-doped samples. Although the doping does not change the crystallographic structure of Li4Ti5O12, they exhibit better cyclability at high charge–discharge rate compared with pristine Li4Ti5O12. Li3.85Na0.15Ti5O12 gives the best cycling performance, only 11.1% loss of capacity after 80 cycles at 2 C charge–discharge rate. Na-doped Li4Ti5O12 exhibits lower potential separation, indicating faster electron transfer kinetics and cycling reversibility. Electrochemical impedance spectroscopy demonstrates that the improved performance of the Na-doped Li4Ti5O12 is due to a small decrease in the charge transfer resistance, indicating high electrochemical activity during cycling. The excellent cycling and safety performance of the Na-doped Li4Ti5O12 electrodes are found to be due to the significantly increased ionic and electronic conductivity. Since fast charge–discharge performance is an important factor that needs to be considered in fabricating power batteries in industry, the Na-doped Li4Ti5O12 materials moves closer to real and large scale applications.
Wet ball-milling route is employed to prepare sulfur-carbon nanotubes composites. The influences of solvents, including ethanol and chloroform, on the structure and electrochemical performance of the composites are firstly investigated. As compared to the conventional dry-milling process, high loose structure and uniform distribution of sulfur can be obtained by adding ethanol during the ball-milling process, and significant enhancement of electrochemical performance is presented. At the current density of 800mAg−1, the discharge capacity can be stably retained at 861.6mAhg−1 after 150 cycles for the composite prepared by adding ethanol, showing obvious advantages over the dry-milling sample and the composite prepared by adding chloroform. When the current density increase to 1600mAg−1, it can still demonstrate a high reversible capacity of 640.9mAhg−1 after 200 cycles. Furthermore, the influence of ball-milling speed is also investigated, but a low utilization of sulfur active materials is obtained after high-energy ball milling process.
Long-term effects of endocrine disruptors (EDs) on aquatic invertebrates remain difficult to assess, mainly due to the lack of appropriate sensitive toxicity test methods and relevant data analysis procedures. This study aimed at identifying windows of sensitivity to EDs along the life-cycle of the freshwater snail Lymnaea stagnalis, a candidate species for the development of forthcoming test guidelines. Juveniles, sub-adults, young adults and adults were exposed for 21 days to the fungicide vinclozolin (VZ). Survival, growth, onset of reproduction, fertility and fecundity were monitored weekly. Data were analyzed using standard statistical analysis procedures and mixed-effect models. No deleterious effect on survival and growth occurred in snails exposed to VZ at environmentally relevant concentrations. A significant impairment of the male function occurred in young adults, leading to infertility at concentrations exceeding 0.025 μg/L. Furthermore, fecundity was impaired in adults exposed to concentrations exceeding 25 μg/L. Biological responses depended on VZ concentration, exposure duration and on their interaction, leading to complex response patterns. The use of a standard statistical approach to analyze those data led to underestimation of VZ effects on reproduction, whereas effects could reliably be analyzed by mixed-effect models. L. stagnalis may be among the most sensitive invertebrate species to VZ, a 21-day reproduction test allowing the detection of deleterious effects at environmentally relevant concentrations of the fungicide. These results thus reinforce the relevance of L. stagnalis as a good candidate species for the development of guidelines devoted to the risk assessment of EDs.
Oxygen evolution reaction (OER) is one of the most important reactions in the energy storage devices such as metal–air batteries and unitized regenerative fuel cells (URFCs). However, the kinetically sluggishness of OER and the high prices as well as the scarcity of the most active precious metal electrocatalysts are the major bottleneck in these devices. Developing low-cost non-precious metal catalysts with high activity and stability for OER is highly desirable. A facile, in situ template method combining the dodecyl benzene sulfuric acid sodium (SDBS) assisted hydrothermal process with subsequent high-temperature treatment was developed to prepare porous Co3O4 with improved surface area and hierarchical porous structure as precious catalysts alternative for oxygen evolution reaction (OER). Due to the unique structure, the as-prepared catalyst shows higher electrocatalytic activity than Co3O4 prepared by traditional thermal-decomposition method (noted as Co3O4-T) and commercial IrO2 catalyst for OER in 0.1 M KOH aqueous solution. Moreover, it displays improved stability than Co3O4-T. The results demonstrate a highly efficient, scalable, and low cost method for developing highly active and stable OER electrocatalysts in alkaline solutions.
The impact of carbon nanofibers as conductive additive on the electrochemical performance of a LiFePO4-based composite electrode for lithium battery is investigated here. We use a new method that allows discriminating between the electronic and the ionic wirings contributions to the polarization and the specific capacity at different discharge rates [C. Fongy, et al., J. Electrochem. Soc., 157 (2010) A885; C. Fongy, et al., J. Electrochem. Soc., 157 (2010) A1347]. Results show this conductive additive is not only beneficial in terms of electronic wiring but it also enables to reach better high rate performance by improving the ionic wiring as it decreases the tortuosity of the porosity within the composite electrode architecture.
An understanding of the pulse discharge behavior of commercial lithium coin cells in wireless sensing systems (WSs) is critical to prolonging the operating life and/or reducing the size of such systems. This paper is part of an effort to examine, model and optimize battery performance for sensor duty cycles consisting of multiple pulse discharges. The transient behavior of the cells during pulse discharge and the relaxation behavior following the pulse are both investigated with single-pulse experiments, and described with a simple mathematical model. In both cases, the voltage response is characterized by a region of rapid change, associated with ohmic and interfacial resistances, followed by a region of slower change. Solid phase diffusion in the cathode is the major contributor to the “slow” voltage change that occurs during and after a pulse. A simple analytical model, validated for this system, was found to accurately describe the time-dependent voltage and the corresponding non-uniform concentration distribution for the porous electrode. This transient study provides insight into and a description of the factors that influence and control battery behavior during pulsed cycling, and provides a tool to enable the next generation of battery-aware design of autonomous wireless sensing systems.
This work involves the use of a new type of composite anode system containing SnSb alloy and Li2.6Co0.4N for lithium secondary batteries based on solid polymer electrolytes. The composite electrode shows a high coulombic efficiency (close to 100% even in the first cycle) and a cycle capacity more than 500mAh/g. An addition of LiN(CF3SO2)2 salt into the electrode by direct powder-mixing will decrease its efficiency and capacity. The cycle performance of a cell, using the composite anode and LiNi0.8Co0.2O2 cathode, can be greatly enhanced by modifying the PEO-based polymer electrolyte with BaTiO3 as filler.
The current multimedia landscape is characterized by a significant heterogeneity in terms of coding and delivery formats, usage environments, and user preferences. The main contribution of this paper is a discussion of the design and functioning of a fully integrated platform for multimedia adaptation and delivery, called NinSuna. This platform is able to efficiently deal with the aforementioned heterogeneity in the present-day multimedia ecosystem, thanks to the use of format-agnostic adaptation engines (i.e., engines independent of the underlying coding format) and format-agnostic packaging engines (i.e., engines independent of the underlying delivery format). Moreover, NinSuna also provides a seamless integration between metadata standards and adaptation processes. Both our format-independent adaptation and packaging techniques rely on a model for multimedia bitstreams, describing the structural, semantic, and scalability properties of these multimedia streams. News sequences were used as a test case for our platform, enabling the user to select news fragments matching his/her specific interests and usage environment characteristics.
Little is known about the association between patient activation, health, service utilization, and cost among mental health (MH) patients. Patients aged 18 to 64 with schizophrenia (Sz, n = 43), bipolar disorder (BD, n = 59), or major depressive disorder (MDD, n = 34) completed the Patient Activation Measure for Mental Health (PAM-MH), the Colorado Symptom Index, demographic, socioeconomic, treatment, and social support questionnaire items. Average PAM-MH score indicated BD patients the most activated (66.6 ± 17.5), Sz (57.4 ± 10.4) less activated, and MDD the least activated (55.4 ± 14.6). The MDD cohort had the highest ($27,616 ± 26,229) and the BD had the lowest total annual healthcare cost ($18,312 ± 25,091). PAM-MH score was inversely correlated with healthcare costs and regression analysis showed a PAM-MH score × gender interaction. The strongest negative relationship between PAM and cost was for males. These analyses support the inverse association between PAM-MH and healthcare service utilization and cost.
One of the most compelling, yet controversial new approaches to educational reform is Multiple Intelligences Theory, or MI. Recent advances in cognitive science, developmental psychology and neuroscience suggest that each person's intelligence is actually made up of autonomous faculties that can work individually or in concert with other faculties. Motivation has, on the other hand, been widely accepted by both teachers and researchers as one of the key factors that influence the rate and success of second/foreign language learning. According to Gardner (1985), there are two types of motivation: integrative and instrumental. An integratively motivated L2 learner shows interest in learning about the culture and the people of the target language, whereas an instrumentally motivated learner has more pragmatic considerations in his/her mind regarding L2 learning, such as obtaining a job or earning more money. Researchers (Arnold and Fonseca, 2004; Christison, 2005) argue that the base of intelligence and the type of motivation a learner possesses, affects the ways s/he favors certain materials and the ways s/he learns them. This study is an attempt to provide empirical evidence to the possible relation between the type and the base of intelligence and motivation, and learners’ satisfaction of EAP textbooks through the analysis of the data obtained from Student Textbook Evaluation Questionnaire, Multiple Intelligences Development Assessment Scales (MIDAS) Questionnaire, and Gardner's Motivation Test Battery (MTB). The results of the study showed that all the bases of intelligences could be found among the EAP students but logical-mathematical, spatial and interpersonal intelligences had the highest rates. The students were also instrumentally motivated and were somehow dissatisfied with their textbooks. Their dissatisfaction can be traced to the design, exercises and content of the textbook.
Information on mass and energy exchange at the soil surface under vegetation is a critical component of micrometeorological, climate, biogeochemical and hydrological models. Under sparse boreal and western conifer forests as much as 50% of incident solar energy reaches the soil surface. How this energy is partitioned into evaporating soil moisture, heating the air and soil remains a topic of scientific inquiry, as it is complicated by such factors as soil texture, litter, soil moisture, available energy, humidity deficits and turbulent mixing. Fluxes of mass and energy near the forest floor of a temperate ponderosa pine and a boreal jack pine stand were evaluated with eddy covariance measurements and a micrometeorological soil/plant/atmosphere exchange model. Field tests showed that the eddy covariance method is valid for studying the mean behavior of mass and energy exchange below forest canopies. On the other hand, large shade patches and sunflecks, along with the intermittent nature of atmospheric turbulence, cause run-to-run variability of mass and energy exchange measurements to be large. In general, latent heat flux densities are a non-linear function of available energy when the forest floor is dry. Latent heat flux densities (λE) are about one-quarter of available energy, when this energy is below 100Wm−2. Latent heat flux density (λE) peaks at about 35Wm−2 when available energy exceeds this threshold. A diagnosis of measurements with a canopy micrometeorological model indicates that the partitioning of solar energy into sensible, latent and soil heat flux is affected by atmospheric thermal stratification, surface wetness and the thickness of the litter layer.
The use of microalgae in the skin care market is already established although the scientific rationale for their benefit was not clearly defined. In this work, the biological activities of dermatologic interest of the water extract from the microalga Botryococcus braunii (BBWE) were evaluated by a battery of in vitro assays. At concentrations ranging from 0.1 to 0.001 % (w/v) BBWE promoted adipocytes differentiation by inhibiting hormone-sensitive lipase, thus promoting triglyceride accumulation in the cells. BBWE also induced gene expression of proteins involved in the maintenance of skin cells water balance such as aquaporin-3 (AQP3), filaggrin (FLG) and involucrin (INV). 0.1 % BBWE increased the gene expression of AQP3 of 2.6-folds, that of FLG and INV of 1.5- and 1.9-folds, respectively. Moreover, it induced the biosynthesis of collagen I and collagen III by 80 and 40 %, respectively, compared to the untreated control. BBWE antioxidant activity, evaluated by oxygen radical absorbance capacity (ORAC) assay, was of 43.5 μmol Trolox per gram of extract: a quite high value among those found for other microalgae extracts. BBWE inhibited the inducible nitric oxide synthase (iNOS) gene expression and the consequent nitrite oxide (NO) production under oxidative stress. At a concentration of 0.02 % BBWE reduced by 50 % the expression of iNOS and by about 75 % the NO production. Taken together, the results demonstrated that B. braunii water extract exerted an array of biological activities concurring with the skin health maintenance; therefore, it is a potential bioactive ingredient to be included in cosmetic products.
Graphene-based metals or metal oxides commonly show outstanding electrochemical performance due to superior properties of graphene. However, it still remains a challenge to directly grow low-valence oxides (e.g. tin monoxide) on graphene surface in term of the oxidizability of graphene oxide, which is normally adopted as a precursor for graphene. Herein, we report a novel strategy for preparation of tin and tin monoxide on graphene nanosheets by selectively using the reducing agent and the precipitant. Moreover, in contrast to free particles formed in solution, nanoscale tin or tin monoxide particles well-dispersed on graphene exhibited enhanced electro-chemical properties, including higher reversible capacities, better cycle performances, and higher rate capabilities. This facile one-step method may provide an attractive alternative approach for preparation of high-performance electrodes consisting of graphene and low-valence compounds.
The predicted dominance of electric vehicles and the need for grid-scale energy storage have heightened concerns that cobalt, a key constituent of lithium-ion batteries, could become a critical limiting factor. With limited terrestrial resources and over half the global production coming from politically challenging regions increasing risk, a shortage of cobalt could be experienced by the early 2020s. Fortunately, the oceans contain about 70 times more cobalt than on land and can be harvested sustainably with passive adsorption technologies; and a symbiotic system using existing offshore structures to harvest cobalt could enhance the economic feasibility of seawater cobalt harvesting. Our study finds that retrofitting just 76 unused oil platforms in the Gulf of Mexico could extract an average of 27.3% of the nation's 2017 cobalt consumption. New Offshore Opportunity for Underwater Cobalt Harvesting has the potential to reduce the cobalt supply pinch point in lithium-ion battery production.
Ac impedance spectra of electrochemical systems are analyzed by considering adequate equivalent circuits, while the differentiation of responses for each elemental step is sometimes difficult. In this study, enlarged impedances were measured by lowering the temperature of a lithium ion battery (LIB) to make the separation of confusing responses easier. The impedance spectra obtained at the temperatures between −20 °C and 20 °C showed drastic change in sizes with shifting of the characteristic frequency. The analysis of impedance spectra using an equivalent circuit revealed changes in resistance of each component and shifting of the time constant for each elemental step. The frequency domain of impedance response of solid electrolyte interphase (SEI) was found to overlap with that of the inductive component of the outer electric lead at 20 °C in our study. The impedance measurement at the low temperatures is considered to be useful for the detection of the SEI and the accurate evaluation of LIB.
The capacity limits, local formation of Li2O2, passivation of active surfaces, and depletion of oxygen by mass transport characteristics in a composite cathode are modeled, numerically simulated, and experimentally evaluated for non-aqueous Li-O2 batteries employing composites of a solid polymer electrolyte and carbon particles as the cathode, Li metal as the anode, and an ion conductive oxide membrane as the separator. Although the theoretical maximum specific energy of the Li-O2 battery is known to be 3458 Wh kg−1 cathode, our simulation predicts a maximum specific energy of 1840 Wh kg−1 cathode with an optimized weight ratio of all essential components as well as cathode thickness. A specific energy of 1713 Wh kg−1 cathode is experimentally demonstrated in a cell with a composite cathode of poly(ethylene oxide) electrolyte and Printex carbon nanoparticles with 48% carbon volume and 30 μm thickness. The model also predicts that the incorporation of voids in the cathode can significantly improve the specific energy.
In this paper we evaluate the local seismic response for thirteen sites located in the municipalities of Arquata del Tronto and Montegallo, two areas which suffered heavy damage during the Mw 6.0 and Mw 5.4 earthquakes which struck Central Italy on August 24, 2016. The input dataset is made by ground motion recordings of 348 events occurred during the sequence. The spectral site response is estimated by the Generalized Inversion Technique and makes use of reference sites. The interpretation is further improved through the information provided by a reference-site independent method (i.e., the so called Receiver-Function Technique) and by the Horizontal-to-Vertical Spectral Ratios of ambient noise recordings. We also provide an independent estimate of the local amplification by comparing the Peak Ground Velocity and the Spectral Amplitudes observed at each site to the value estimated by well-established Ground Motion Prediction Equations for a rock-class site. The results obtained by the adopted methodologies are all highly consistent, and they emphasize the different seismic behavior of several sites at local scale. Thus, sites located on Quaternary deposits overlying the bedrock, such as Castro, Pretare, Spelonga, Pescara del Tronto, and Capodacqua feature some relevant amplifications in a medium (2–10 Hz) frequency range; two sites at Spelonga show amplifications also at low frequencies; three sites located on stiff formations, i.e. Uscerno, Balzo and Colle d’Arquata, respectively, feature either nearly neutral response or low amplification level. A probable topographic effect was identified at the rock site of Rocca di Arquata (MZ80).
Problem Statement Although some consider college student self-efficacy a unified construct with recommendations for measurement using questionnaires with total scores with “high reliability and validity”, separate analyses of subdomains may be warranted. Research Question Are there different findings at the subscale level in models of college student self-efficacy (course and social) that consider sex, language fluency and use, academic year, stress preventive resources, and depressive symptomology? Purpose of the Study This paper considers a contextual psycho-social model of college-student well-being among undergraduates at an English-language university in an ethno-culturally/linguistically diverse city in British Columbia, Canada. It differentiates between patterns of association of key variates from the model with two identified subdomains of college student self-efficacy, i.e., course and social subdomains. Research Method Participants were undergraduates at a mid-sized university. Participants completed a battery of questionnaires. Data on focal variables [college self-efficacy (course and social), background variables (sex, immigrant/citizenship generation, instructional language fluency and use, academic year), personality s, stress preventive resources, and depressive symptomology] were included in multivariate general linear model (GLM), hierarchical regression and correlational analyses. Findings Multivariate GLM analyses of the college self-efficacy subscales yielded omnibus effects (SSType I) for generation, language fluency and home use, academic year, select personality and stress preventive resources variates (ps<.05). Although there were key commonalities, the pattern of statistical significance differed by criterion variable in corresponding univariate GLM (SSType I) and hierarchical regression analyses. Conclusions Examination of the College Self-Efficacy Inventory and its subscales highlights that although overall scores may be of use, comparative analyses of findings at the subscale level should be considered. Importantly, it is not sufficient to compare/contrast ‘statistical significance’ profiles, statistical comparisons of corresponding correlations elucidates differential findings and assists developing nomothetic networks and targeted interventions to improve student outcomes.