batterydata/paper-abstracts huggingface dataset:
The occurrence of a sunflower oil spill in 2007 in the Con Joubert Bird Sanctuary freshwater wetland, South Africa, inhibited the growth of sensitive phytoplankton species and promoted that of tolerant species. The algal divisions Chlorophyta and Euglenophyta were well represented in the sunflower oil contaminated water, especially the species Euglena sociabilis, Phacus pleuronectes and Chlamydomonas africana. Young and mature resting zygotes of Chlamydomonasafricana were recorded in high abundance at all the sunflower oil contaminated sampling sites. The phytobenthos diversity and abundance were significantly suppressed and negatively associated with low Dissolved Oxygen concentrations and the negative redox potential of the bottom sediment. At the intracellular level, phytoplankton chlorophyll a and b concentrations as physiological variables were more sensitive indicators of the adverse effects of sunflower oil than the 72 h Selenastrum capricornutum algal bioassay conducted.
The electrochemical performance of Na–air batteries have a significant dependence on the type of electrocatalyst used for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Herein, a dual-phase spinel MnCo2O4 with nitrogen-doped reduced graphene oxide hybrid (dp-MnCo2O4/N-rGO) employed in a hybrid Na-air battery system was demonstrated simultaneous electrocatalytic characteristic toward both ORR and OER, which showed comparable ORR and superior OER catalytic performance over commercial Pt/C. The fabricated dual-phase cobalt manganese spinel nanoparticles, the introduced dopants (nitrogen atoms), and the electrical and chemical coupling between the oxide nanoparticles and nanocarbon backbones significantly contribute to the high catalytic performance of dp-MnCo2O4/N-rGO. The proposed catalyst exhibited a slightly higher discharge voltage of 2.75V and lower charge voltage of 3.14V compared to that of a commercial Pt/C (2.73 and 3.35V, respectively). The hybrid battery showed a low overpotential of 0.39V and improved round-trip energy efficiency. The battery exhibited excellent discharge stability and no significant degradation was observed during the 25 cycles due to the moderate particle size of dp-MnCo2O4 and large active N-doped surface area. Therefore, dp-MnCo2O4/N-rGO could be a promising bifunctional catalyst for enhancing the electrochemical performance of hybrid Na-air batteries.
Alternative energy conversion systems with high efficiency, low cost and environmental benignity attract increasing attention. Herein, we astonishedly found that one new M-Nx complex, cobalt corrole [Co(tpfc)(py)2] (where, tpfc=5,10,15-tris(pentafluorophenyl) corrole and py=pyridine, denoted as Co-TPFC), adsorbed on the surface of multi-walled carbon nanotube (MWNT) (namely, Co-TPFC/MWNT) displayed an outstanding electrocatalytic property towards the reduction of oxygen (O2). The resultant electrocatalyst Co-TPFC/MWNT without pyrolysis treatment or covalent binding demonstrated a direct 4e reduction of O2 to water in acid media, while producing the 2e reduction product of H2O2 in a minimal amount. Meanwhile, our catalyst exhibited better long-term durability and higher tolerance to methanol compared to commercially used high-cost Pt/C catalyst. These results suggest that the Co-TPFC/MWNT catalyst is a technologically promising candidate for practical applications in metal-air batteries and fuel cells.
Background Vestibular dysfunction has been long described in patients with migraine; this relation has been addressed as vestibular migraine. The pathophysiology as well as the peripheral or central localization of this deficit is unclear. Cervical vestibular evoked myogenic potential (cVEMP) is a validated method to test saccular function and vestibulocollic pathway. Objectives The current work was designed to assess the characteristics of cVEMP response in patients with vestibular migraine and compare them with the results of healthy controls, and to find out if the cVEMP could be useful as a complementary tool for testing vestibular function in vestibular migraine. Methods Twenty five patients with definite vestibular migraine were involved as a study group. Twenty healthy volunteers of comparable age and sex were taken as a control group. The amplitude and latency of cVEMP were measured. Electronystagmography (ENG) test battery including caloric testing was done. Results Our study demonstrated significant reduction in cVEMP amplitudes, and more frequently absent response in patients with vestibular migraine compared to healthy controls. There was no correlation between cVEMP amplitudes and caloric testing. ENG tests showed peripheral vestibular lesion in 36% of patients, central lesion in 16%, mixed lesion in 4%. Conclusion cVEMP is a useful complementary tool for testing vestibular function in vestibular migraine. Reduced cVEMP amplitude or absent response were the most frequent features in vestibular migraine. The saccule and or the sacculo-collic pathway are affected in vestibular migraine, with more tendencies for peripheral vestibular dysfunction in our patient group.
In this work, a new nanostructure of SnO2 nanoparticles (NPs) encapsulated into hollow TiO2 nanowires (SnO2@TiO2) has been successfully fabricated. This unique architecture intrinsically possess void space in between the TiO2 shell and SnO2 nanoparticle cores, as confirmed by XRD, XPS, SEM, TEM and HRTEM characterizations. The TiO2 shell of the composite can not only alleviate the pulverization and drastic volume change of the SnO2 NPs and maintain the structural integrity, but also contribute to the total capacity of the composite. Moreover, the void space can also accommodate the volume expansion of SnO2 and provide highly efficient channels for the fast transport of both electrons and lithium ion during discharge/charge cycling process. When tested as potential anode materials for lithium ion batteries, the as-prepared hollow TiO2 nanowires shell encapsulating SnO2 NPs architecture exhibits good lithium storage performance and excellent cyclability (which delivers a higher reversible capacity of 445 mAh g−1 at 800 mA g−1 after 500 cycles). The unique architecture should be responsible for the superior electrochemical performance.
Flexible Li-O2 batteries have attracted worldwide research interests and been considered to be potential alternatives for the next-generation flexible devices. Nitrogen-doped carbon nanofibers (N-CNFs) prepared by electrospinning are used as flexible substrate and an amorphous TiO2 layer is coated by atomic layer deposition (ALD) and then decorated with Ru nanoparticles. The Ru/N-CNFs@TiO2 composite is directly used as a free-standing electrode for Li-O2 batteries and the electrode delivers a high specific capacity, improved round-trip efficiency and good cycling ability. The superior electrochemical performance can be attributed to the amorphous TiO2 protecting layer and superior catalytic activity of Ru nanoparticles. Based on density functional theory (DFT) calculations from first principles, the carbon electrode after coating with TiO2 is more stable during discharge/charge process. The analysis of Li2O2 on three different interfaces (Li2O2/N-CNFs, Li2O2/TiO2, and Li2O2/Ru) indicates that the electron transport capacity was higher on Ru and TiO2 compared with N-CNFs, therefore, Li2O2 could be formed and decomposed more easily on the Ru/N-CNFs@TiO2 cathode. This work paves a way to develop the free-standing cathode materials for the future development of high-performance flexible energy storage systems.
Despite impressive declines in average prices, there is wide dispersion in the prices of U.S. solar photovoltaic (PV) systems; prices span more than a factor of four. What are the characteristics of the systems with low-prices? Using detailed characteristics of 42,611 small-scale (<15kW) PV systems installed in 15 U.S. states during 2013, we identify the most important factors that make a system likely to be low-priced (LP). Comparing LP and non-LP systems, we find statistically significant differences in nearly all characteristics for which we have data. Logit and probit model results robustly indicate that LP systems are associated with: markets with few active installers; experienced installers; customer ownership; large systems; retrofits; and thin-film, low-efficiency, and Chinese modules. We also find significant differences across states, with LP systems much more likely to occur in some states, such as Arizona, New Jersey, and New Mexico, and less likely in others, such as California. Our focus on the left tail of the price distribution provides implications for policy that are distinct from recent studies of mean prices. While those studies find that PV subsidies increase mean prices, we find that subsidies also generate LP systems. PV subsidies appear to simultaneously shift and broaden the price distribution. Much of this broadening occurs in a particular location, northern California.
A nanosized LiMn2O4 (nano-LiMn2O4) spinel was prepared by a novel route using a porous silica gel as a sacrificial hard template. This material was found to be made up of 8–20nm nanoparticles with a mean crystallite size of 15nm. The electrochemical properties of nano-LiMn2O4 were tested in lithium cells at different cycling rates and compared to those of microsized LiMn2O4 (micro-LiMn2O4) obtained by the classical solid state route. Microsized LiMn2O4 is formed by 3–20μm agglomerates, the size of each individual particle being approximately 0.20μm. The behaviour of nano-LiMn2O4 as a positive electrode improves with increasing current densities (from C/20 to 2C). Moreover, it was found to exhibit a noticeably better performance at high rates (2C), with higher initial capacity values and very good retention (only 2% loss after 30 cycles), with respect to micro-LiMn2O4, almost certainly due to enhanced lithium diffusion in the small particles.
Surface-driven charge storage materials based on both electrochemical double layer (EDL) formation and pseudocapacitive behavior can deliver high energy and power capabilities with long-lasting cycling performance. On the other hand, the electrochemical performance is strongly dependent on the material properties, requiring sophisticated electrode design with a high active surface area and a large number of redox-active sites. In this study, hierarchically nanoporous pyropolymer nanofibers (HN-PNFs) were fabricated from electrospun polyacrylonitrile nanofibers by simple heating with KOH. The HN-PNFs have a hierarchically nanoporous structure and an exceptionally high specific surface area of 3,950.7m2 g−1 as well as numerous redox-active heteroatoms (C/O and C/N ratio of 10.6 and 16.8, respectively). These unique material properties of HN-PNFs resulted in high reversible Na-ion capacity of ∼292mAhg−1 as well as rapid kinetics and stable cycling performance in the cathodic potential range (1-4.5V vs. Na+/Na). Furthermore, energy storage devices based on HN-PNFs showed a remarkably high specific energy of ∼258 Wh kg−1 at ∼245Wkg−1 as well as a high specific power of ∼21,500Wkg−1 at ∼78 Wh kg−1, with long and stable cycling behaviors over 2,000 cycles.
A model based on empirical relationships is used to study frequency and magnitude of the sediment resuspension by wind-induced waves. The model has been developed for Laguna Galarza, a mesotrophic round-shaped shallow lake located in Esteros del Iberá wetland. Given the logistic and accessibility difficulties of this macrosystem, the installation of automated field stations facilitated continuous data acquisition. Using the wave theory, a daily spatial model of resuspension was built from simultaneous time series of hourly measurements of infrared nephelometric turbidity, wind speed and wind direction. The model was used to predict total suspended solids in another lake of the wetland (Laguna Iberá) showing a good agreement with observed field values, even although Laguna Iberá has a more irregular contour and a eutrophic state. Finally, we apply the model to discuss the ecological impacts of resuspension on the distribution of the littoral communities and to characterize the composition of the particulate suspended matter of the limnetic ecosystem. The model was useful to simulate the possible implications of the recent alterations of the wetland water level on the resuspension regime of the open water bodies.
Solid state glass electrolyte, xLi2O-(1− x)(yB2O3-(1− y)P2O5) glasses were prepared with wide range of composition, i.e. x =0.35–0.5 and y =0.17–0.67. This material system is one of the parent compositions for chemically and electrochemically stable solid-state electrolyte applicable to thin film battery. Lithium ion conductivity of Li2O–B2O3–P2O5 glasses was studied in the correlation to the structural variation of glass network by using FTIR and Raman spectroscopy. The measured ionic conductivity of the electrolyte at room temperature increased with x and y. The maximum conductivity of this glass system was 1.6×10−7 Ω−1 cm−1 for 0.45Li2O–0.275B2O3–0.275P2O5 at room temperature. It was shown that the addition of P2O5 reduces the tendency of devitrification and increases the maximum amount of Li2O added into glass former without devitrification. As Li2O and B2O3 contents increased, the conductivity of glass electrolyte increased due to the increase of three-coordinated [BO3] with a non-bridging oxygen (NBO).
The study of the effects of migration on migrants themselves has not garnered nearly as much attention within the recent international migration literature as other topics, such as motives for migration, the effects of immigration on receiving countries, and the effects of emigration on countries of origin. Focusing instead on these effects on migrants themselves, an issue of primary importance to the discussion of international migration, I present novel data collected through household interviews in communities both in Mexico and the United States. Data gathered using an ethnosurvey approach, combining the techniques of ethnographic fieldwork with representative survey sampling in order to collect both quantitative and qualitative data, permit a careful comparison of absolute and relative wage gains for interviewees with data from existing Mexican surveys. Key findings include: (1) upon crossing the border, even given the cost of migration, migrants indeed stand to collect large net absolute gains, average incomes increasing more than fivefold immediately; (2) relative gains are large, many migrants moving from the lower deciles of origin wage distributions to the top deciles; and (3) average gains accruing to migrants surpass those of even the most successful current programs of economic development. In turn, these findings verify the importance of including consideration for the migrants themselves in any ongoing discussions of how to construct effective migration policy around the world.
MnO2 is regarded as an ideal material of supercapacitor since its low-cost, environment friendly and high specific capacitance but hindered by its poor electrical conductivity. Developing a composite electrode that combines nano-structure MnO2 with a conductive skeleton such as carbon materials could make up for the shortcomings. Here, porous activated carbon (PAC) is synthesized by using low-cost wheat bran as biomass carbon precursor and a mixture of NaCl/ZnCl2 as combined solvent-porogen. The resultant PAC sample presents a hierarchical porous structure and large specific surface area up to 1058 m2 g−1. Afterwards, MnO2 nanosheets decorated PAC (MnO2@PAC) is prepared via an in-situ hydrothermal deposition. It is a key finding that the ion/electron transfer kinetics of MnO2@PAC could be effectively improved by the addition of hierarchical porous carbon. Thus, the MnO2@PAC electrode displays a high specific capacitance (258 F g−1 at 1 A g−1) and superior rate performance (82.8% capacitance retention with the current density ranging from 1 A g−1 to 20 A g−1). Furthermore, an asymmetric supercapacitor is assembled by employing the MnO2@PAC as the positive electrode and PAC as negative electrode, which exhibits a high energy density of 32.6 Wh kg−1 and as well as 93.6% capacity retention at over 10,000 charge/discharge cycles.
To investigate the possibility of a cost-effective direct borohydride fuel cell (DBFC), the performance enhancement of a single cell is investigated under practical running conditions by adopting non-precious metal for the anode. Fluorinated Zr-based AB2-type hydrogen storage alloy with an effective area of 100cm2 is selected as the anode catalyst. To minimize pressure loss from the enlarged cell size, a parallel-type anode channel is designed, then the principal reasons for performance degradation are analyzed. Single-cell performance is mainly enhanced by adopting a corrugated anode design, applying an anti-corrosion coating on the cathode channel, and controlling the fuel flow-rate and air humidity. The cell performance is estimated simply by measuring the wall temperature of the cell.
To enhance the long stability of sulfur cathode for a high energy lithium–sulfur battery system, a sulfur–carbon sphere composite was prepared by encapsulating sulfur into micropores of carbon spheres by thermal treatment of a mixture of sublimed sulfur and carbon spheres. The elemental sulfur exists as a highly dispersed state inside the micropores of carbon spheres with a large surface area and a narrow pore distribution, based on the analyses of the X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET), thermogravimetry (TG) and local element line-scanning. It is demonstrated from galvanostatic discharge–charge process, cyclic voltammetry (CV) and electrochemical impedance spectra (EIS) that the sulfur–carbon sphere composite has a large reversible capacity and an excellent high rate discharge capability as cathode materials. In particular, the sulfur–carbon sphere composite with 42 wt% sulfur presents a long electrochemical stability up to 500 cycles, based on the constrained electrochemical reaction inside the narrow micropores of carbon spheres due to strong adsorption. Therefore, the electrochemical reaction constrained inside the micropores proposed here would be the dominant factor for the enhanced long stability of the sulfur cathode. The knowledge acquired in this study is important not only for the design of efficient new electrode materials, but also for understanding the effect of the micropores on the electrochemical cycle stability.
In the field of SLA, there have been various attempts to define second language learning motivation and to discover relationships between motivation and gender. Using two well-known motivational models: Expectancy-value theory, and Gardner’s Socio-educational model, the present study sought to (1) first define foreign language learning motivation in a particular EFL setting and (2) then explore differences in motivational sub-constructs based on the variable of gender. A previously tested motivational scale was administered to 453 second-year non-English majors. Factor analysis of the results revealed a multidimensional construct comprised of Integrativeness, Intrinsic value, Amotivation, and Attainment value, together explaining 54.4% of the variance. A MANOVA was then performed with gender as the independent variable. The results of the MANOVA indicated a significant difference in Integrativeness based on gender, with females scoring significantly higher on those items. The results are discussed in relation to both the Socio-educational model and Expectancy-value theory, and with reference to their relevance in the EFL classroom.
A high-performance lithium ion capacitor (LIC) composed of activated carbon (as the positive electrode) and pre-lithiated C-coated Si/SiO x nanospheres (as the negative electrode) is investigated as a potential energy storage system for high-power and high-energy applications. Under optimized pre-lithiation conditions, the feasibility of pre-lithiated C-coated Si/SiO x nanospheres is thoroughly examined as an advanced negative electrode compared with a conventional graphite LIC using pre-lithiated C-coated Si/SiO x nanospheres. The pre-lithiated C-coated Si/SiO x nanospheres show much improved reversible capacity and rate capability with higher capacity retention at a high current density of 10C up to 1000 cycles compared with a conventional LIC. Such improvements may be attributed to the unique physical and chemical properties of C-coated Si/SiO x nanospheres. We believe that this approach provides a practical guideline for developing and successfully implementing advanced LICs.
The connection between spatial reasoning and mathematics learning and pedagogy in primary school children has been the subject of an increasing number of studies in recent years. There has been no comprehensive analysis, however, of how studies based on spatial reasoning interventions may lead to improvements in students’ mathematics learning in school classroom environments. This article considers 18 studies selected from a combined systematic literature review of 133 studies, from Scopus and Education Research Complete (ERC) using PRISMA, and 23 studies recommended by the research team from bibliographies of major international research centres with a spatial reasoning dedication. This combination approach has allowed a synthesis of research and practice in an analytical way, assisting construction of a framework for spatial reasoning interventions for consideration in developing core knowledge and skills within the primary school mathematics curriculum. The findings highlight the importance of designing and evaluating spatial reasoning programs for primary school children in order to improve students’ mathematics classroom learning, including evidence from standardized tests, as they progress through the school system. The article supports the need for further research on interventions that provide sustainable school-based spatial reasoning programs.
The electroanalytical behavior of Li x NiO2 and Li x Co0.2Ni0.8O2 was studied by simultaneous application of slow-scan rate cyclic voltammetry (SSCV), potentiostatic and galvanostatic intermittent titration (PITT and GITT), and electrochemical impedance spectroscopy (EIS). Application of a finite-space diffusion model for treating the results obtained by these techniques allowed us to calculate the diffusion coefficient of Li ions (D) and the differential (incremental) capacity (C int) as functions of the electrode’s potential. Our final purpose was to compare D versus E and C int versus E plots for both the electrodes, in order to correlate the observed difference in their electroanalytical behavior with the clear distinction in the related Li-insertion mechanisms deduced from XRD studies. While Li insertion into Li x Co0.2Ni0.8O2 exhibits a single-phase reaction upon charge in the 3.0–4.08V (versus Li/Li+) range, Li intercalation into Li x NiO2 undergoes two-phase transitions in the same potential range. The shape of both plots, D versus E and C int versus E for these electrodes, is discussed in the framework of a finite-space diffusion model and Li-insertion processes that can be described by Frumkin-type intercalation isotherms with short-range attraction interactions among intercalation sites.