batterydata/paper-abstracts huggingface dataset:
This paper presents the modeling and supervisory energy management design of a hybrid fuel cell/battery-powered passenger bus. With growing concerns about petroleum usage and greenhouse gas emissions in the transportation sector, finding alternative methods for vehicle propulsion is necessary. Proton Exchange Membrane (PEM) fuel cell systems are viable possibilities for energy converters due to their high efficiencies and zero emissions. It has been shown that the benefits of PEM fuel cell systems can be greatly improved through hybridization. In this work, the challenge of developing an on-board energy management strategy with near-optimal performance is addressed by a two-step process. First, an optimal control based on Pontryagin's Minimum Principle (PMP) is implemented to find the global optimal solution which minimizes fuel consumption, for different drive cycles, with and without grade. The optimal solutions are analyzed in order to aid in development of a practical controller suitable for on-board implementation, in the form of an Auto-Regressive Moving Average (ARMA) regulator. Simulation results show that the ARMA controller is capable of achieving fuel economy within 3% of the PMP controller while being able to limit the transient demand on the fuel cell system.
Electrochemical reactions of surface-fluorinated petroleum coke (petroleum coke heat-treated at 2800°C: PC2800) electrodes have been investigated by cyclic voltammetry and XPS analysis. Three reduction peaks were observed at 2.31V, 0.70–0.74V and 0.46–0.59V versus Li/Li+ in the first reduction curves of cyclic voltammograms. The peak at 2.31V appeared only for PC2800fluorinated at 500°C. Two reduction peaks were also observed at 0.71V and 0.59V for surface-oxidized PC2800. The surface oxygen was increased through the electrode preparation process while the amount of surface fluorine was reduced by hydrolysis. The reduction peak at 2.31V shows the reduction of fluorine bonded to basal plane of graphite, and those at 0.46–0.59V are due to the reduction of ethylene carbonate (EC) as a solvent. The peak at 0.70–0.74V would be also attributed to the reduction of EC on the hydrophilic sites of partly oxidized PC2800 surface.
Rechargeable lithium-ion batteries (LIBs) are currently accepted to be one of the most suitable energy storage resources in portable electronic devices because of their high gravimetric and volumetric energy density. To understand the behavior of Li+ ions on electrochemical lithium extraction/insertion process, we performed in situ 7Li nuclear magnetic resonance (NMR) measurements for LiCoO2 cathode in a plastic cell battery, and the spectral evolutions of the 7Li NMR signal of Li x CoO2 (0≤ x ≤1) were well investigated. Very narrow solid solution region of Li x CoO2 (∼0.99≤ x <1) was explicitly defined from the large intensity reduction of LiCoO2 signal at ∼0ppm, which is related to the localized nature of the electronic spin of paramagnetic Co4+ ion formed at the very early delithiation stage. With further decreasing the signal intensity of LiCoO2, a Knight-shifted signal corresponding to an electrically conductive Li x CoO2 phase emerged at x =0.97, which then monotonously decreased in intensity for x <0.75 in accordance with the electrochemical lithium de-intercalation from Li x CoO2. These observations acquired in situ fully confirm the earlier studies obtained in ex situ measurements, although the present study offers more quantitative information. Moreover, it was shown that the peak position of the NMR shift for Li x CoO2 moved as a function of lithium content, which behavior is analogous to the change in its c lattice parameter. Also, the growth and consumption of dendritic/mossy metallic lithium on the counter electrode was clearly observed during the charge/discharge cycles.
The surface of LiNi0.8Co0.15Al0.05O2 (NCA) cathode material is modified with different percentages of Y2O3 through a wet chemical-calcination method to improve its electrochemical performance for using in lithium-ion batteries. The XRD results show that surface modification does not change the crystalline structure of NCA. The x wt% Y2O3-decorated (0.05 ≤ x ≤ 2) samples exhibit improved cyclability and rate-capability compared to pristine NCA. SEM images along with elemental mapping of Y show the uniform coverage of the NCA particles surface with yttrium oxide. The 1 wt% Y2O3-decorated NCA electrode exhibited a specific capacity of 181 mAh g−1 after 50 cycles at 0.5C, while that was 134 mAh g−1 for the pristine one. These specific capacities are equivalent to capacities retention of 93% and 69% for optimized electrode and pristine one, respectively. The enhanced electrochemical performance of the optimized Y2O3-decorated NCA is due to the protective and conducting roles of yttrium oxide, which are clearly manifested in the results of electrochemical impedance spectrometry. Yttrium oxide, by the surface modification of the active material, diminishes the side reactions between NCA particles and the electrolyte. Besides, yttrium oxide increases the electrical conductivity of the electrode by establishing a good electrical connection with the active material.
The spatial and temporal dynamics of soil temperature (T SOIL) strongly influence a wide range of biotic and abiotic processes in boreal forests. Relatively few spatial and temporal T SOIL measurements have been made in these systems; in addition, not all ecosystem models take into account the effect of changing stand structure during stand development on T SOIL dynamics. The goals of this study were to measure T SOIL and its spatiotemporal variability in a boreal forest chronosequence, develop and test a computationally simple empirical model to predict T SOIL, and quantify the effects of different approaches to deriving T SOIL on simulated ecosystem processes. T SOIL was measured hourly at six depths (0–100cm) for 3–4 years, and sampled in a spatial grid monthly during one growing season, in a black spruce (Picea mariana (Mill.) BSP)-dominated boreal forest chronosequence. We report annual and daily T SOIL patterns, air–soil hystereses, and T SOIL changes at the freeze-thaw transition. An empirical model predicting T SOIL as of the weighted sum of past air temperatures generally accounted for 90–95% of temporal T SOIL variability at shallow depths, and 77–83% at 50–100cm. A variety of stand structural characteristics affected the model parameters, with leaf area index (LAI) usually the most significant. Spatial T SOIL correlation, measured at depths of 2 and 10cm, was generally constant between 5 and 30m. The new empirical model that accounts for changes in canopy structure greatly improved the prediction of T SOIL for stands with high LAI in the Biome-BGC process model; the broader implications of this change are discussed. This model has simple data requirements – only air temperature and LAI – although the parameters given here should only be used for boreal stands with similar soil types.
Achilles tendinopathy (AT) is a common condition, causing considerable morbidity in athletes and non-athletes alike. Conservative or physical therapies are accepted as first-line management of AT; however, despite a growing volume of research, there remains a lack of high quality studies evaluating their efficacy. Previous systematic reviews provide preliminary evidence for non-surgical interventions for AT, but lack key quality components as outlined in the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) Statement. The aim of this study was to conduct a systematic review and meta-analysis (where possible) of the evidence for physical therapies for AT management.
Thin films of lithium nickel vanadates (Li x NiV y O z ) have been prepared by radio frequency magnetron sputtering from a LiNiVO4 target. The discharge gas was either pure argon or a mixture of argon and oxygen. The deposition rates as well as the composition and morphology of the films strongly depend on the sputtering parameters. For a total pressure of 1Pa, the V/Ni atomic ratio varies between 0.75 for films developed in a pure argon plasma and 1.65 when the partial pressure of oxygen is 100mPa. The thin film containing the two types of transition metals in an equiatomic ratio (Li1.1NiVO4) has given the best electrochemical properties as an anode displaying a specific capacity that became stable at 1000mAh/g after three cycles, which is at least as high as for bulk material.
The harmful side reactions between the cathode materials and liquid electrolyte within the lithium secondary batteries will deteriorate the performance of the cathode materials and batteries. The Li2O–2B2O3 glass with high Li+ conductivity and stability can be coated on the surface of LiNi0.8Co0.2O2 powders by mixing LiNi0.8Co0.2O2, LiOH·H2O and H3BO3 and heating the mixture at 500°C for 10h. The structure of the surface-treated and base LiNi0.8Co0.2O2 powders was characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM) and BET. It is shown the Li2O–2B2O3 layer can prevent LiNi0.8Co0.2O2 from contacting directly with liquid electrolyte, and minimize the side reactions within the batteries. The surface-treated LiNi0.8Co0.2O2 cathode material has increased reversible capacity, decreased irreversible capacity, stabilized cycling performance, reduced self-discharge, especially the improved high temperature performance. The results indicated that the surface treatment should be an effective way to improve the comprehensive properties of the cathode materials for lithium secondary batteries.
Abstract Chapter 5 has introduced the macromolecules present in a cell. We have learnt that one of the macromolecules, DNA, carries the genetic information. In this chapter, we shall address the question as to how the genetic information is transferred from DNA to another macromolecule, RNA, in a process called transcription. We shall see that transcription is an outcome of the interaction between an enzyme called RNA polymerase (RNAP) and the DNA. Therefore, specific structural features of these two macromolecules will be considered to explain the interaction, and thus, understand the mechanism of transcription, first in bacteria and then in eukaryotes. Further, we shall see that RNAP-DNA interaction is facilitated or impeded by other molecules in the cell. Pertinent structural features of some of these facilitators and inhibitors will also be considered to understand how the process of transcription is regulated.
Distributed generation (DG) using renewable energy resources, is intended to reduce the impact of power generation from fossil fuels on climate change. Microgrids (MGs) represent a method of interconnecting several low voltage (LV) renewable energy sources and loads to the distribution system. Multi-microgrids (MMGs) integrate distributed generators (DGs) and MGs with medium voltage (MV) distribution systems. Protection system design for MGs pose significant challenges due to bi-directional flow from DGs as well as lower fault current levels due to the inverter connected DG sources in islanded MGs. This paper reviews the coordination strategies and protection schemes that have been proposed for MGs to address these challenges. The protection coordination strategies based on communication and time grading including their relative performance are described. The advantages and limitations of existing MG protection schemes are discussed. As most of these protection schemes apply to relatively small MGs, they may need to be extended for larger MG configurations in practical power systems. Some future directions for research in the protection system design for both MGs and MMGs are also outlined in this paper.
In the past decade, researchers in the fields of energy production have concentrated on the improvement of new energy storage devices. Lithium-ion batteries (LIBs) and faradaic supercapacitors (FSs) have attracted special attention as a result of the rapid development of new electrode nanomaterials, especially hybrid nanomaterials, which can meet the increasingly higher requirements for future energy, such as the capability to deliver high-power performance and an extremely long life cycle. In these hybrid nanostructures, a series of synergistic effects and unique properties arising from the combination of individual components are a major factor leading to improved charge/discharge capability, energy density, and system lifetime. This paper describes the most recent progress in the growth of hybrid electrode materials for LIBs and FSs systems, focusing on the combination of zero-dimensional (0D), one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) nanomaterials, respectively.
Aniline doped with polyvinyl sulphonate (PV-SO3 −) was electropolymerised on screen printed carbon (SPCE) and glassy carbon (GCE) electrodes. Then nano-structured polystyrene (PSNP) latex beads functionalised with amine (PSNP-NH2) and sulphate (PSNP-OSO3 −) were self-assembled on the modified SPCE and GCE. The resultant polyaniline nanocomposites (PANI|PSNP-NH2 or PANI|PSNP-OSO3 −) were characterised by cyclic voltammetry (CV), UV–vis spectroscopy and scanning electron microscopy (SEM). Brown–Anson analysis of the multi-scan rate CV responses of the various PANI films gave surface concentrations of the order of 10−8 molcm−2. UV–vis spectra of the PANI films dissolved in dimethyl sulphoxide showed typical strong absorbance maxima at 480 and 740nm associated with benzenoid π–π* transition and quinoid excitons of polyaniline, respectively. The SEM images of the PANI nanocomposite films showed cauliflower-like structures that are <100nm in diameter. When applied as electrochemical nitrite sensor, sensitivity values of 60, 40 and 30μA/mM were obtained for electrode systems containing PANI|PSNP-NH2, PANI and PANI|PSNP-SO3 −, respectively. The corresponding limits of detection of the sensors were 7.4, 9.2 and 38.2μM NO2 −.
The aim of the present work is to generalize an ion transport phenomena observed in composite polymeric electrolytes using the previously developed models as well as design a new approach which would be helpful in describing changes in conductivity and lithium ion transference numbers occurring upon addition of fillers to polymeric electrolytes. The concept is based on the observation of changes in ionic associations in the polymeric electrolytes studied in a wide salt concentration range. The idea is illustrated by the results coming from a variety of electrochemical and structural data obtained for composite electrolytes containing specially designed inorganic and organic fillers.
The elucidation of the reaction rate-determining step nature in intercalation processes is essential for the development of approaches for the precise control of rate-limiting factors. In this work, we explore the kinetic patterns of lithium-ion intercalation into two model cathode materials (LiCoO2 and LiMn2O4) and develop criteria for distinguishing between Butler-Volmer slow charge transfer and slow chemical steps. A numerical model for the rate-limiting ion desolvation step is developed and the predictions of the model are compared with the experimental voltammetric and electrochemical impedance spectroscopy data. We show that slow desolvation step results in essential changes in the shape of both cyclic voltammetry and impedance responses with the kinetic resistance vs. potential dependencies being highly informative for the reaction rate control diagnostics. The consideration of the intercalation kinetics in four solvents (water, propylene carbonate, acetonitrile and dimethyl sulfoxide) allows concluding on the influence of the resistivity of surface layer/electrode material interface on the reaction slow step nature.
In the eastern province of Zambia, three companies for solar energy services have been operating for more than two years, with 400 clients paying for the use of solar photovoltaic (PV) installations. Clients do not become owners of the systems. Instead, the company continues to charge a fee for keeping the systems in operation. In this way, the useful lifetime of the solar systems is increased, and clients have local access to skilled service and spare parts. The fees for solar services cover the full operational costs of the companies, including battery replacement and makes them independent of further support from government or donors. Results to date show that clients are happy with their systems, which are of a standard solar home (SHS) size of 50 Wp, with four lights and a socket for radio or other light DC appliance. This is in spite of paying a higher price than what was previously spent on candles and kerosene for lighting. The most important benefit cited among the clients is that children now have the possibility to do their homework in the evening. The second most highly valued feature is entertainment, such as radio and video. Solar systems contribute to increased income earning opportunities especially in the service sector. The poorest rural people cannot afford to pay for a solar system in their house, but benefit from systems in the shops.
Tin dioxide nanoparticles on nitrogen doped graphene aerogel (SnO2-NGA) hybrid are synthesized by one-step hydrothermal method and successfully applied in lithium-ion batteries as a free-standing anode. The electrochemical performance of SnO2-NGA hybrid is investigated by galvanostatic charge–discharge cycling, rate capability test, cyclic voltammetry and electrochemical impedance spectroscopy. It is found that the SnO2-NGA hybrid with freestanding spongy-like structure exhibit remarkable lithium storage capacity (1100 mAh g−1 after 100 cycles), good cycling stability and high rate capability. The outstanding performance is attributed to the uniform SnO2 nanoparticles, unique spongy-like structure and N doping defect for Li+ diffusion.
A non-aqueous zinc–polyaniline secondary battery was fabricated with polyaniline Emeraldine base as cathode and zinc metal as anode in an electrolyte consisting of 0.3 M zinc-bis(trifluoromethyl-sulfonyl)imide Zn(TFSI)2 dissolved in propylene carbonate. We observed that the formation of the battery required a prerequisite condition to stabilize the interfaces in order to maintain a stable capacity. The battery suffered from Zn dissolution which induces a competition between concurrent Zn dissolution and plating when the battery is in charge mode, and thus inefficient cycles are obtained. The capacity and coulombic efficiency of the battery depends on the charge–discharge rates. We propose cycling protocols at different rates to determine the steady-state rates of competing reactions. When the cell is cycled at ≥1 C rate, the coulombic efficiency improves. The maximum capacity and energy densities of the battery are 148 mAhg−1 and 127 mWhg−1, respectively for discharge at C/2. The battery was successively charged/discharged at constant current densities (1C rate), and high cycling stability was obtained for more than 1700 cycles at 99.8% efficiency. Zinc dissolution and self discharge of the battery were investigated after 24 h of standby. The investigation showed that the battery experiences a severe self-discharge of 48% per day.
Aluminum is examined as energy storage and carrier. To provide the correct feasibility study the work includes the analysis of aluminum production process: from ore to metal. During this analysis the material and energy balances are considered. Total efficiency of aluminum-based energy storage is evaluated. Aluminum based energy generation technologies are reviewed. Technologies are categorized by aluminum oxidation method. Particularly, the work focuses on direct electrochemical (anodic) oxidation of aluminum, aluminum–water reaction in alkaline solution, mechanochemical activation of aluminum, mechanical activation of aluminum and high-temperature aluminum–water reaction. The objective is methods overview including technological principle, efficiency, urgent problems and possible application areas.
First-principles calculations have been performed on the polymorphs of Li2FeSiO4 and the corresponding delithiated products. The calculated results indicate that a structural transformation from the pristine (P2 1 /n) structure to cycled (P2 1 /n-cycl or Pmn2 1 -cycl) polymorph would occur in the first charge cycle. Then, Li ions can be reversibly intercalated/deintercalated into/from the cycled structures in the subsequent cycles. More importantly, our results show that ∼1.5 Li ions can be extracted from the P2 1 /n-cycl Li2FeSiO4, corresponding to two redox reactions of Li2FeSiO4/LiFeSiO4 and LiFeSiO4/Li0.5FeSiO4, which can be used to understand the experimentally obtained high capacity of over 200mAh/g, as well as the different charge–discharge behaviors observed in different experiments. Moreover, the oxidation of Fe2+ to Fe3+ ions is observed upon the first Li removal, while charge balance upon further delithiation is achieved mainly by the oxidation of oxygen ions and partly by iron. Finally, the structural evolution during the charge–discharge process, as well as the Li diffusion mechanism in the P2 1 /n-cycl structure, is also investigated.
Background Cognitive deficits are a central feature of schizophrenia but it is not certain how cognitive functioning changes over time. The purpose of this prospective longitudinal study was to determine the temporal change of cognitive functioning and the predictors of cognitive performance from among demographic, clinical, and biological variables. Methods Participants were individuals with schizophrenia or schizoaffective disorder whose cognitive functioning was assessed at multiple time points with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS). At the baseline visit participants had a blood sample drawn from which C-reactive protein, antibodies to Herpes Simplex Virus type 1, and selected genetic polymorphisms were measured. Repeated measures linear regression was used to determine whether cognitive measures changed over time and which variables predicted cognitive performance. Results The sample consisted of 132 participants, mean age 43.7years at baseline, who received a median of 3 cognitive assessments over a period averaging 2.8years. The RBANS Total score and Language index showed no statistically significant temporal change; performance on two indices, Immediate Memory and Attention, showed modest but statistically significant improvements (gains of 0.89±0.33 and 0.76±0.29 points per year, respectively); Visuospatial/Constructional performance showed a modest but statistically significant decline (of 0.80±0.25 points per year). Few variables predicted cognitive performance; however greater psychiatric symptom severity was associated with worse cognitive performance for most cognitive measures. Conclusions Cognitive functioning in middle-aged persons with schizophrenia showed an absence of decline for most measures and modest gains in some measures.