batterydata/paper-abstracts huggingface dataset:
This study is an attempt to explore the nature of L2 teachers’ motivation towards English language learning and their decision to become English teachers. A total of 45 third-year prospective Primary school English teachers at the University of the Balearic Islands completed a small-scale survey adapted from Gardner's Attitude/Motivation Test Battery (AMBT) in order to investigate their main type of motivation (integrative or instrumental) (Gardner, 1985). Results show that participants are clearly integratively motivated towards English language learning. However, in line with Dornyei's ‘L2 motivational self-system’ theory (2009), results suggest a no longer clear-cut separation between integrative and instrumental motivation.
NH3 insertion mechanism into the (2×2) tunnel structure of a hollandite-type manganese oxide (H-Hol) and the (2×∞) layered structure of a birnessite-type manganese oxide (H-Bir) were studied by direct adsorption calorimetry. It was found that H-Bir has a smaller NH3 adsorption enthalpy (−ΔH d,NH3 ) compared to H-Hol because of the structural flexibility of its MnO sheets. NH3 insertion into the tunnel structure of H-Hol is divided into two stages: in the initial stage, NH3 molecules interact with the H+ sites at the external surfaces and near the tunnel entrance, giving a peak in −ΔH d,NH3 curve at a low adsorption temperature due to the energy barrier required to expand the lattice structure; in the secondary stage, NH3 can access the inner H+ sites in the tunnel, giving a broad shoulder in −ΔH d,NH3 curve. H2O/H+ contents in H-Hol have an important role in NH3 insertion. Porous manganese oxides have a comparable or much higher −ΔH d,NH3 value compared to zeolites having a similar pore dimension or of a same proton form.
A scientific theory is an explanation of a set of related observations, phenomena, or events based upon one or more hypotheses and verified multiple times by the evidence of detached groups of researchers. Cognitive load theory (CLT) was designed “to provide guidelines intended to assist in the presentation of information in a manner that encourages learner activities that optimize intellectual performance (Sweller et al. 1998 p. 25).” The theory proved successful in inspiring many experimental studies aimed at testing the CL effects of instructional design for over 20 years (Clark et al. 2006). On the other hand, a growing number of educational psychologists and researchers has identified many conceptual, methodological, and practical limitations of the theory (Bannert 2002; Brünken et al. 2009; Horz and Schnotz 2009; Moreno 2006; Schnotz and Kürschner 2007). The concerns voiced by de Jong (this issue) resonate with those critiques and suggest the need to reflect carefully on the scientific value of the theory.
Layered Li(Co0.5Ni0.5)1−yFeyO2 (0.0 ≤ y ≤ 0.25) oxides were prepared by citric-acid assisted sol–gel method. Elemental and structural properties were investigated by energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Raman scattering (RS) and Mössbauer spectroscopy, and magnetometry. EDX images show a homogeneous distribution of Fe ions. XRD and RS spectroscopy reveal that the materials crystallize as a LiNiO2 LiCoO2 LiFeO2 solid solution with the typical rhombohedral α-NaFeO2 structure (R 3 ¯ m S.G.) up to y = 0.2 at which composition a secondary phase was observed. For y > 0.2 the XRD results show the appearance of the α-LiFeO2 phase with the cubic structure (Fm3m S.G.). The degree of cation mixing investigated by XRD analysis and magnetic measurements is z < 0.04, for y < 0.2. Electrochemical tests of Li(Co0.5Ni0.5)1−yFeyO2 (0.0 ≤ y ≤ 0.1) oxides in lithium cells show the influence of iron substitution. The best results have been obtained for the composition y(Fe) = 0.05, where the electrical conductivity is maximum. A specific capacity 32 mAh g−1 is maintained at 8C rate.
Fluoroethylene carbonate (FEC)-based electrolytes using FEC as the co-solvent (50 wt%) are investigated and compared with the electrolyte using FEC as the additive (10 wt%) for freestanding Si-carbon nanotubes (CNTs) composite paper anodes for Li-ion batteries. The ethylene carbonate (EC)-free FEC-based electrolyte is found to achieve higher specific capacity and better capacity retention in terms of long-term cycling. After 500 cycles, the capacity retention of the cell using diethyl carbonate (DEC)-FEC (1:1 w/w) is increased by 88% and 60% compared to the cells using EC-DEC-FEC (45:45:10 w/w/w) and EC-FEC (1:1 w/w), respectively. Through SEM-EDX and XPS analyses, a possible reaction route of formation of fluorinated semicarbonates and polyolefins from FEC is proposed. The inferior cell performance related to the EC-containing electrolytes is likely due to the formation of more polyolefins, which do not favor Li ion migration.
The heat generation of LiMn2O4, Li1.156Mn1.844O4, and Li1.06Mn1.89Al0.05O4 spinel cathode materials in a half-cell system was investigated by isothermal micro-calorimetry (IMC). The heat variations of the Li/LiMn2O4 cell during charging were attributed to the LiMn2O4 phase transition and order/disorder changes. This heat variation was largely suppressed when the stoichiometric spinel was doped with excess lithium or lithium and aluminum. The calculated entropy change (dE/dT) from the IMC confirmed that the order/disorder change of LiMn2O4, which occurs in the middle of the charge, was largely suppressed with lithium or lithium and aluminum doping. The dE/dT values obtained did not agree between the charge and the discharge at room temperature (25°C), which was attributed to cell self-discharge. This discrepancy was not observed at low temperature (10°C). Differential scanning calorimeter (DSC) results showed that the fully charged spinel with lithium doping has better thermal stability.
In this paper, the potential and the cost-effectiveness of a solar photovoltaic power plant for meeting the energy demand of garment zone at Jaipur (India) is analyzed. Also, the energy demand of garment zone for year 2011has been estimated (2.21MW) and the design of the solar PV power plant of 2.5MW capacity has been proposed, which requires about 13.14acres of land area. Looking at the scarcity and cost of the land near the city, an off-site proposal for the power plant has also been considered and compared with the on-site option. For the on-site solar PV power plant internal rate of return (IRR) is 11.88%, NPV @ 10% discount rate is 119.52 million INR, simple payback period is 7.73 years and discounted payback period @10% is 15.53 years, while for the off-site power plant IRR is 15.10%, NPV is 249.78 million INR, simple payback period is 6.29 years and discounted payback period is 10.14 years. Levelized cost of energy is Rs. 14.94 and Rs. 11.40perkWh for on-site and off-site solar PV plants respectively @ 10% discount rate, which is quite attractive.
N-doped porous carbon materials derived from urea-modified lignin were prepared via efficient KOH activation under carbonization. The synthesized N-doped carbon materials, which displayed a well-developed porous morphology with high specific surface area of 3130 m2 g−1, were used as electrode materials in symmetric supercapacitors with aqueous and solid electrolytes. In consistent with the observed physical structures and properties, the supercapacitors exhibited specific capacitances of 273 and 306 F g−1, small resistances of 2.6 and 7.7 Ω, stable charge/discharge at different current densities for over 5000 cycles and comparable energy and power density in 6 mol L−1 KOH liquid and KOH-PVA solid electrolytes, respectively.
A significant amount of energy is consumed to maintain thermal comfort in buildings, a huge portion of which is lost through windows. Smart coating, thin films with spectrally selective properties on the surface of glass, is the innovative solution to the problem. Thermochromic smart windows change their color and optical properties in response to temperature variations. The performance, materials, coating technologies and energy modeling of thermochromic windows are reviewed in the present study. The effect of doping vanadium dioxide (VO2) coatings with different dopants such as tungsten, fluorine, gold nanoparticles and etc. is elaborated. Various deposition techniques, specifically hybrid chemical vapor deposition (AA/APCVD) and physical vapor deposition (PVD) methods are elucidated. Different dopants and techniques show different results on metal to semiconductor transition (MST) and the critical temperature. The “change in visible and infra-red transmission and reflectance” is the touchstone of performance for the different afforded chromogenic intelligent windows.
Mammalian brain expresses multiple nicotinic acetylcholine receptor (nAChR) subtypes that differ in subunit composition, sites of expression and pharmacological and functional properties. Among known subtypes of receptors, α4β2* and α6β2*-nAChR have the highest affinity for nicotine (where * indicates possibility of other subunits). The α4β2*-nAChRs are widely distributed, while α6β2*-nAChR are restricted to a few regions. Both subtypes modulate release of dopamine from the dopaminergic neurons of the mesoaccumbens pathway thought to be essential for reward and addiction. α4β2*-nAChR also modulate GABA release in these areas. Identification of selective compounds would facilitate study of nAChR subtypes. An improved understanding of the role of nAChR subtypes may help in developing more effective smoking cessation aids with fewer side effects than current therapeutics. We have screened a series of nicotinic compounds that vary in the distance between the pyridine and the cationic center, in steric bulk, and in flexibility of the molecule. These compounds were screened using membrane binding and synaptosomal function assays, or recordings from GH4C1 cells expressing hα7, to determine affinity, potency and efficacy at four subtypes of nAChRs found in brain, α4β2*, α6β2*, α7 and α3β4*. In addition, physiological assays in gain-of-function mutant mice were used to assess in vivo activity at α4β2* and α6β2*-nAChRs. This approach has identified several compounds with agonist or partial agonist activity that display improved selectivity for α6β2*-nAChR.
A reversible fuel cell (RFC), which integrates a fuel cell with an electrolyzer, is similar to a rechargeable battery. This technology lies on high-performance bifunctional catalysts for the oxygen reduction reaction (ORR) in the fuel cell mode and the oxygen evolution reaction (OER) in the electrolyzer mode. Current catalysts are platinum group metals (PGM) such as Pt and Ir, which are expensive and scarce. Therefore, it is highly desirable to develop PGM-free catalysts for large-scale application of RFCs. In this mini review, we discussed the most promising nanocarbon/oxide composite catalysts for ORR/OER bifunctional catalysis in alkaline media, which is mainly based on our recent progress. Starting with the effectiveness of selected oxides and nanocarbons in terms of their activity and stability, we outlined synthetic methods and the resulting structures and morphologies of catalysts to provide a correlation between synthesis, structure, and property. A special emphasis is put on understanding of the possible synergistic effect between oxide and nanocarbon for enhanced performance. Finally, a few nanocomposite catalysts are discussed as typical examples to elucidate the rules of designing highly active and durable bifunctional catalysts for RFC applications.
This paper describes the use of a frequency domain, finite-difference scheme to simulate the impedance spectra of diffusion in porous microstructures. Both open and closed systems are investigated for a range of ideal geometries, as well as some randomly generated synthetic volumes and tomographically derived microstructural data. In many cases, the spectra deviate significantly from the conventional Warburg-type elements typically used to represent diffusion in equivalent circuit analysis. A key finding is that certain microstructures show multiple peaks in the complex plane, which may be misinterpreted as separate electrochemical processes in real impedance data. This is relevant to battery electrode design as the techniques for nano-scale fabrication become more widespread. This simulation tool is provided as an open-source MatLab application and is freely available online as part of the TauFactor platform.
To cope at their homes, community-dwelling older people surviving a hip fracture need a sufficient amount of functional ability and mobility. There is a lack of evidence on the best practices supporting recovery after hip fracture. The purpose of this article is to describe the design, intervention and demographic baseline results of a study investigating the effects of a rehabilitation program aiming to restore mobility and functional capacity among community-dwelling participants after hip fracture.
Cardiovascular safety is an important consideration in the debate on the benefits versus the risks of electronic cigarette (EC) use. EC emissions that might have adverse effects on cardiovascular health include nicotine, oxidants, aldehydes, particulates, and flavourants. To date, most of the cardiovascular effects of ECs demonstrated in humans are consistent with the known effects of nicotine. Pharmacological and toxicological studies support the biological plausibility that nicotine contributes to acute cardiovascular events and accelerated atherogenesis. However, epidemiological studies assessing Swedish smokeless tobacco, which exposes users to nicotine without combustion products, generally have not found an increased risk of myocardial infarction or stroke among users, but suggest that nicotine might contribute to acute cardiovascular events, especially in those with underlying coronary heart disease. The effects of aldehydes, particulates, and flavourants derived from ECs on cardiovascular health have not been determined. Although ECs might pose some cardiovascular risk to users, particularly those with existing cardiovascular disease, the risk is thought to be less than that of cigarette smoking based on qualitative and quantitative comparisons of EC aerosol versus cigarette smoke constituents. The adoption of ECs rather than cigarette smoking might, therefore, result in an overall benefit for public health.
Abstract Electric vehicles are commonly seen as one of the alternatives to reduce the oil dependency and the greenhouse gas emissions in the transport sector. The aim of this paper is to evaluate the impact of different electric vehicle charging strategies on the national grid including the storage utilization of electric vehicles (V2G-vehicle to grid). Furthermore, an economic analysis of electric vehicle utilization is performed and the results are compared with the conventional diesel vehicle. To accomplish this aim the availability of passenger cars in Germany to be plugged into the grid showed to be high at any time over the day (>89%), which is advantageous for the V2G concept. The impact of the different electric vehicle charging strategies is investigated by employing three scenarios. The first scenario (unmanaged charging) shows that 1 mil. electric vehicles only impacts slightly on the daily peak electricity demand. In the second scenario (Grid stabilizing storage use) a maximum reductions of grid fluctuations of 16% can be achieved with the use of 1 mil. electric vehicles as storage. The last scenario (profit maximization by power trading) the maximum daily revenues from V2G activities are calculated to be 0.68 EUR2009.
Off-grid solar photovoltaics (PV) are promoted as an economical renewable energy system for providing electricity in remote locations far from the grid. However, without on-going maintenance, the performance of these systems will diminish due to battery deterioration leaving them unable to provide the service they were initially designed for. This paper presents analysis and results from a four week cross-disciplinary investigative study carried out in September 2012 into the performance of off-grid PV in health centres and schools in rural communities in Rwanda. A socio-technical approach was taken to understand the reasons for failure. A strategy was subsequently developed to influence user behaviour and increase the PV array size to reduce capacity shortage through the year and improve the lifetime of the lead acid batteries found on these systems. According to the results obtained, the total costs to implement off-grid PV systems can be reduced. Furthermore, the proposed strategy reduces the operating costs of PV below that of a diesel generator according to a projection of prices found in Rwanda which is important in a donor led installation model.
In July 1997, the European members of the Advanced Lead–Acid Battery Consortium were awarded a second Brite-EuRam contract for research on lead–acid batteries for electric vehicles (EVs). This Project, entitled ‘Strategies for the further improvement of performance and life of lead–acid batteries for electric vehicle applications’, commenced at the beginning of January 1998, is costing some US$4 million, and is scheduled to run for 3 years. The Project is divided into three principal tasks. The first is concentrating on separator design and compression in order to improve cycle-life. In the second task, attempts are being made to improve the specific energy of tubular-plate designs, which traditionally have good life characteristics in traction applications. In addition, work is being carried out to determine the effects of rapid-charging techniques on this type of battery design. The third task is attempting to improve the performance of negative plates by seeking improved expanders. The Project has now reached its mid-point. This paper describes the work in progress and discusses some of the results achieved to date and their implication for the future of the research programme.
Ordered mesoporous carbon (OMC) was synthesized by an evaporation induced self-assembly method, under acidic conditions, with resorcinol as the carbon precursor and Pluronic F127 triblock copolymer (EO106PO70EO106) as a structure directing agent. The obtained OMC product was characterized by N2 sorptometry, X-ray diffractometry and Raman spectroscopy. The mean pore radius of 2nm and specific surface area of 712 m2 g−1 were found. The OMC sample was subjected to a complex electrochemical testing in order to check for its applicability in various energy conversion processes. For pure OMC, the charge storage properties and kinetics of oxygen reduction reaction (ORR) in alkaline solution were measured. The OMC sample delivered specific capacitance of 232 F g−1 at 5mV s−1 with 83.6% capacitance retained at 100mV s−1. Effective ORR electrocatalysis by OMC in alkaline media was evidenced, with onset potential amounting to −0.10V vs. saturated calomel electrode. A part of the OMC sample was used as a support of Pt nanoparticles, and examined as electrocatalyst for hydrogen evolution reaction (HOR) and ORR in acidic media. Reversible HOR kinetics was observed, while ORR performances were found to be competitive to the ones on other carbon-supported Pt electrocatalysts reported so far. A superb electrochemical behavior was correlated to physico-chemical properties of OMC. Described OMC stands out as a highly versatile material, which can be used to replace carbon materials developed for specific purposes, allowing rationalization of carbon-based technologies aimed for energy conversion purposes.
Sap flow measurement techniques and evaluation of data are reviewed. Particular attention is paid to the trunk segment heat balance (THB) and heat field deformation (HFD) methods based on 30 years experience. Further elaboration of sap flow data is discussed in terms of integrating flow for whole stems from individual measuring points, considering variation of radial patterns in sapwood and variation around stems. Scaling up of data from sets of sample trees to entire forest stands based on widely available biometric data (partially on remote sensing images) is described and evaluated with a discussion of the magnitude of errors, the routine procedure applicable in any forest stand and practical examples.
One of the most important challenges for further development of solid oxide fuel cells is to design new electrodes which operate at intermediate temperatures. In this sense, the formation of nanostructures of the Pr0.6Sr0.4Fe0.8Co0.2O3:Ce0.8Sm0.2O2 composite and their characterization have been carried out. These nanostructures have been synthesized using polymeric membranes with 0.1μm pore size as templates. The electronic microscopy has been used in order to confirm the dimensions of the obtained nanotubes with a wall thickness of 20nm. The impedance spectroscopy measurements reveal the good performance of these nanostructured materials and the effect that the nanostructures and the addition of a pure ionic conductor have on the electrochemical performance. The synthesized nanostructured composite exhibits an area specific resistance (ASR) value smaller than that obtained for the sample without the nanostructured morphology together with the addition of the pure ionic conductor.
Lithium-rich nickel–manganese–cobalt oxide, Li1.2Ni0.18Mn0.59Co0.03O2, prepared by spray-dry process, exhibits rapid capacity fade and poor rate capability. The surface of Li1.2Ni0.18Mn0.59Co0.03O2 can be modified with LiCoPO4 through co-precipitation method in order to improve its electrochemical properties. The resultant LiCoPO4 particles are in nano-scale and accumulate on the surface of the Li1.2Ni0.18Mn0.59Co0.03O2 particles. The surface modification by LiCoPO4 is shown to significantly improve both the cyclic performance and the rate capability of Li1.2Ni0.18Mn0.59Co0.03O2.
Insufficient catalytic activity and durability are key barriers to the commercial deployment of low temperature polymer electrolyte membrane (PEM) and direct-methanol fuel cells (DMFCs). Recent observations suggest that carbon-based catalyst support materials can be systematically doped with nitrogen to create strong, beneficial catalyst-support interactions which substantially enhance catalyst activity and stability. Data suggest that nitrogen functional groups introduced into a carbon support appear to influence at least three aspects of the catalyst/support system: 1) modified nucleation and growth kinetics during catalyst nanoparticle deposition, which results in smaller catalyst particle size and increased catalyst particle dispersion, 2) increased support/catalyst chemical binding (or “tethering”), which results in enhanced durability, and 3) catalyst nanoparticle electronic structure modification, which enhances intrinsic catalytic activity. This review highlights recent studies that provide broad-based evidence for these nitrogen-modification effects as well as insights into the underlying fundamental mechanisms.
Understanding the formation of SEI films on Li4Ti5O12 (LTO) anodes offers a major benefit to large-scale applications of lithium ion batteries made therefrom. This paper reveals that an SEI film is formed above 1 V due to the interfacial reaction between the electrode and electrolyte: LTO anodes are previously considered free from SEI films when cycled between 1 and 3 V. The reactivity and the formation of SEI films are much affected by the morphology and surface area of the electrode. To study the above, LTO powders with different morphologies are synthesized using lithium acetate (LA) and lithium hydroxide (LH) as the lithium sources. LTO–LH consisting of agglomerates of primary small particles with a large surface area has higher reactivity than LTO–LA with a cubic structure and small surface area. As a result, the LTO–LH anode with a smooth SEI film offers better cyclic performance than the LTO–LA anode with a porous SEI film. The addition of vinylene carbonate to the electrolyte facilitates rapid formation of a protective SEI film on LTO–LA, greatly improving the rate and cyclic performance: stable specific capacity of 155.6 mAh g−1 and remarkable 135.2 mAh g−1 after 500 cycles at 10 C are recorded.