batterydata/paper-abstracts huggingface dataset:
Acetonitrile contamination in an operating cell and performance recovery are investigated in detail by a series of electrochemical characterizations, including constant current operation, electrochemical impedance spectroscopy, cyclic voltammetry, linear scanning voltammetry and chronoamperometry. We demonstrate that 20 ppm of acetonitrile in the air stream causes an approximate 40% reduction in cell performance at 1 A cm−2; however, the neat air operation completely restores the single cell. Cell performance degradation and recovery display two distinguishable periods that correspond to the effect of catalyst activity and electrolyte proton conductivity, respectively. The potential effect on acetonitrile contamination is also studied in a non-operating H2/N2 cell. The results indicate that low and high potentials cause a larger proton conductivity effect than a medium potential. Two recovery methods were conducted to restore cell performance after contamination in N2 at different potentials. The neat air operation completely mitigated the poisoning effect in approximately 5 h regardless of contamination history; however, the N2 purge and subsequent potential scans, even scanning up to 1.5 V vs hydrogen reference electrode, did not affect the poisoned cell. The liquid water generated in catalyst layers may play an important role during the recovery from acetonitrile contamination in a proton exchange membrane fuel cell.
An adequate and reliable electricity supply system is essential for any developing country. This paper examines the problems in the electricity supply system in Nigeria. Solar photovoltaic (PV) systems are reckoned to be viable alternatives for reliable power supply, particularly for small loads in remote areas and rural communities. The status and potential of photovoltaics in Nigeria are examined, particularly for village electrification and telecommunications. Results of surveys of PV systems installed in the country are presented and policies that would encourage the dissemination of the systems are discussed.
A study is conducted to examine the motion, dynamic and electric consumption characteristics of an electric assisted bicycle based on the effects of certain operating conditions and structural parameters. Simulation models for operation of the electric assisted bicycle, including dynamic models of the electric assisted bicycle and battery models, are established. These simulation models are solved by MATLAB-Simulink to provide the operating characteristics of the electric assisted bicycle. Based on the established mathematical models, the motion, dynamic and electric consumption of the electric assisted bicycle are analyzed and optimized under the effects of slope, bicycle mass, wheel radius, crank length, and sprocket transmission ratio. The simulation results show that the dynamic performance and electric consumption of the electric assisted bicycle are significantly improved by reducing the bicycle mass, wheel radius, and increasing the sprocket transmission ratio. The dynamic performance and electric consumption are optimal when the slope grade, bicycle mass, wheel radius, crank length, and sprocket transmission ratio are 0%, 12 kg, 0.32 m, 0.17 m and 3.43, respectively. A study for using the regenerative energy generated during the downhill movement of the electric assisted bicycle to create electrical power is presented under the effects of rider mass and slope angle. An experimental study is also conducted to examine the motion and electric consumption characteristics of the electric assisted bicycle under real operating conditions. This study shows agreement between simulation and experimental results at the same initial conditions.
The effect of milling time on the morphology of graphite is characterized by XRD, SEM, BET, FTIR and XPS and the electrochemical response of the resulting materials upon lithium-ion absorption is analyzed using different techniques. As milling time is increased, the particle size diminishes and the amount of oxygen content increases. Concomitantly, the capacity for lithium adsorption also increases because new adsorption sites become available due to more surface area and oxygen functional groups. These effects are interpreted using first-principles calculations, which show that the presence of oxygenated species promotes lithium adsorption at higher potentials. This capacity increase is probably not relevant for lithium-ion batteries since there is no intercalation process but rather an adsorption one, but may be of interest for supercapacitive applications. Diffusion coefficients of lithium for different graphite particle sizes are evaluated. The effects of diffusion, particle size and oxygen content are discussed.
Background Repetitive transcranial magnetic stimulation (rTMS) has been identified as a potentially valuable tool for the rehabilitation of language impairment after left hemisphere (LH) stroke, in populations of persons with chronic aphasia. Applied to a homologue to Broca’s area, rTMS is posited to modulate bilateral language networks, promoting measurable behavioral language change, in accordance with theories of transcallosal disinhibition arising from the damaged LH. Objective/Hypothesis The current investigation is an open-label study, presenting detailed case and group presentations on a population of seven nonfluent aphasic participants. Behavioral language performance is presented on expressive and receptive language measures up to 8 months after a 10-day protocol of 1 Hz stimulation. This research aims to provide longitudinal behavioral language outcomes for persons with aphasia, subsequent to rTMS and supplement previous studies to inform the clinical efficacy of rTMS. Results In accordance with previous investigations, significant improvements in picture naming, spontaneous elicited speech and auditory comprehension were found. Time of testing was identified as a significant main effect. Significant improvements in picture naming accuracy and decreases in picture naming latency were also identified. The results demonstrate sustained language improvements up to 8 months subsequent to TMS application. Conclusions The results of this investigation are consistent with the findings of previous research studies, reporting behavioral language changes after rTMS in nonfluent aphasia. Additional evidence is provided to demonstrate that rTMS may facilitate retrieval mechanisms involved in picture naming.
We investigated the electronic structures of low-molecular-weight dithiobiuret (DTB) compounds in both reduced and oxidized states along with those of a DTB polymer in the discharged and charged states using X-ray absorption near edge structure (XANES) measurements. DTB is a simple and lightweight organosulfur molecule with two neighboring tautomeric thiol/thione groups (–SH/>CS) that can form disulfide (S–S) bonds by reversible oxidative cyclization. The DTB polymer, composed of alternating DTB and phenylene (Ph) units, exhibited a high capacity (about 260 mA h g−1) without any significant degradation in the charge and discharge cycle characteristics. Based on XANES measurements, charge–discharge experiments, and quantum chemical calculations, we propose that the reactions of two types of redox couples contribute the redox reaction of the DTB polymer.
The increasing levels of solar power affect the usage and development of electricity grids, both at local distribution level and with respect to potential congestion within the transmission grid. We use a cost-minimising investment model (ELIN) to determine the development of the European electricity generation system up to Year 2050, for two renewable-dominated scenarios: the Green Base scenario, with a Europe-wide, technology-neutral renewable certificate scheme; and the Net Metering scenario, with an additional net metering support scheme for solar power. The system compositions are extracted from the ELIN results for the years 2022 and 2032, and analysed in an hourly dispatch model (EPOD) to study the effects of solar power on marginal electricity costs and transmission congestion. From the results of the investment model, it is clear that the presence of a net metering subsidy scheme significantly affects both the pace at which solar power continues to expand and the geographical distribution of the new capacity. In the dispatch modelling, it can be seen that high penetration levels of solar power have a strong effect on the marginal costs of electricity, since production is concentrated around a few hours each day. At penetration levels of 20–30% of annual electricity demand, solar power production entails a predictable daily marginal cost difference between the solar peak and the evening price peak, which could make short-term storage competitive. Transmission congestion during summer is consistently higher in the systems from the Net Metering scenario than in those from the Green Base scenario, while the opposite is true during winter. Solar power production correlates strongly with congestion 6–9h after the solar peak, whereas wind power correlates with congestion with respect to more slowly evolving and longer-term variations.
A one-step moderate-explosion assisted carbonization strategy is demonstrated for the synthesis of sulfur and nitrogen dual-doped porous carbon nanosheets (CNSs) using the mixture of camellia petals and ammonium persulfate. The ammonium persulfate acts as both explosive and dopant precursor. The prepared porous carbon nanosheets have high BET surface than 1122 m2 g−1 with sulfur and nitrogen contents of 1.34% and 4.89%, respectively, which benefit the improvement of conductivity, wettability and active sites for electrochemical reaction. The electrochemical tests as electrodes materials for supercapacitor, lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) indicate that the prepared sulfur and nitrogen dual-doped porous carbon nanosheets possess superior energy-storage performance. The specific capacitances of the CNS–800 symmetric two-electrode supercapacitors using 6 M KOH liquid and KOH/PVA solid-state electrolytes for high current density of 20 A g−1 are up to 176.2 F g−1 and 136.0 F g−1, respectively. The CNS–800 anodes exhibit high capacities as well as good cycle performance with capacitance of 310 mA h g−1 and 129 mA h g−1 after 1000 cycles at 0.2 A g−1 for LIBs and SIBs, respectively. The results provide a novel route for low-cost and large-scale production of CNSs electrode materials for high-performance electrochemical energy storage devices.
Household air pollution (HAP) generated from solid fuel combustion is a major health risk. Direct measurement of exposure to HAP is burdensome and challenging, particularly for children. In a pilot study of the Household Air Pollution Intervention Network (HAPIN) trial in rural Guatemala, we evaluated an indirect exposure assessment method that employs fixed continuous PM2.5 monitors, Bluetooth signal receivers in multiple microenvironments (kitchen, sleeping area and outdoor patio), and a wearable signal emitter to track an individual’s time within those microenvironments. Over a four-month period, we measured microenvironmental locations and reconstructed indirect PM2.5 exposures for women and children during two 24-h periods before and two periods after a liquefied petroleum gas (LPG) stove and fuel intervention delivered to 20 households cooking with woodstoves. Women wore personal PM2.5 monitors to compare direct with indirect exposure measurements. Indirect exposure measurements had high correlation with direct measurements (n = 62, Spearman ρ = 0.83, PM2.5 concentration range: 5–528 µg/m3). Indirect exposure had better agreement with direct exposure measurements (bias: −17 µg/m3) than did kitchen area measurements (bias: −89 µg/m3). Our findings demonstrate that indirect exposure reconstruction is a feasible approach to estimate personal exposure when direct assessment is not possible.
Publisher Summary The contents of the chapter are drawn upon from the personal experiences of the authors obtained from working with people for 12 years. The first section of the chapter explores the particular research approach of the authors. It describes how the methodology affects the entire process of the research. The second section enumerates the priors that are to be considered while planning a research. The third section outlines the methods of the research in detail and discusses the implications of the methods for managing the research. The fourth section presents an overview of the practical aspects of working in a research team. And the last section provides an overall reflection on “doing research.” The chapter concludes that research is an activity that is best enjoyed when working with a team because working in a team ensures the possibility that someone would be there to help. Managing a research team is about planning and coordinating activity. Research is an approach to life and should not be considered a separate “work” activity.
It has been consistently reported that children with autism spectrum disorders (ASD) show considerable handwriting difficulties, specifically relating to accurate and consistent letter formation, and maintaining appropriate letter size. The aim of this study was to investigate the underlying factors that contribute to these difficulties, specifically relating to motor control. We examined the integrity of fundamental handwriting movements and contributions of neuromotor noise in 26 children with ASD aged 8–13 years (IQ>75), and 17 typically developing controls. Children wrote a series of four cursive letter l's using a graphics tablet and stylus. Children with ASD had significantly larger stroke height and width, more variable movement trajectory, and higher movement velocities. The absolute level of neuromotor noise in the velocity profiles, as measured by power spectral density analysis, was significantly higher in children with ASD; relatively higher neuromotor noise was found in bands >3Hz. Our findings suggest that significant instability of fundamental handwriting movements, in combination with atypical biomechanical strategies, contribute to larger and less consistent handwriting in children with ASD.
A facile sol-gel thermolysis route was adopted to synthesize KNiPO4 nano-sheets for the design of hybrid supercapacitors. The phase purity, homogeneity, and functional groups present in the synthesized KNiPO4 were characterized through X-ray diffraction and FTIR measurements. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images showed that the nano-sheet-like particles were loosely stacked. The electrochemical properties of the KNiPO4 electrode were studied in various aqueous-based electrolytes such as 1M LiOH, 1M NaOH, and 1M KOH to explore their superior performances. Among these electrolytes, the KNiPO4 electrode provided a maximum specific capacity of 278 Cg−1 in 1M KOH at 5mVs−1. A hybrid supercapacitor was fabricated using the synthesized KNiPO4 as the positive electrode and activated carbon as the negative electrode in a 1M KOH aqueous electrolyte. The supercapacitor exhibited a specific capacitance of 48Fg−1 in 1M KOH at 0.6mAcm−2 and energy density of 13Whkg−1 at a power density of 59Wkg−1. In addition, the hybrid system retained 93% of its initial specific capacitance even after 2000 cycles. A KNiPO4-based hybrid system thus exhibits superior characteristics and hence is a promising candidate for high-performance electrochemical energy storage devices.
The aim of the present study was to perform a representative survey among German dentists about attitudes, practice, and experience regarding single-tooth repair restorations.
Simple, computationally efficient battery models can contribute significantly to the development of flow batteries. However, validation studies for these models on an industrial-scale stack level are rarely published. We first extensively present a simple stack voltage model for the Vanadium Redox Flow Battery. For modeling the concentration overpotential, we derive mass transfer coefficients from experimental results presented in the 1990s. The calculated mass transfer coefficient of the positive half-cell is 63% larger than of the negative half-cell, which is not considered in models published to date. Further, we advance the concentration overpotential model by introducing an apparent electrochemically active electrode surface which differs from the geometric electrode area. We use the apparent surface as fitting parameter for adapting the model to experimental results of a flow battery manufacturer. For adapting the model, we propose a method for determining the agreement between model and reality quantitatively. To protect the manufacturer's intellectual property, we introduce a normalization method for presenting the results. For the studied stack, the apparent electrochemically active surface of the electrode is 41% larger than its geometrical area. Hence, the current density in the diffusion layer is 29% smaller than previously reported for a zero-dimensional model.
The simple preparation of Co3O4 nanoparticles from a solid organometallic molecular precursor N-N′-bis(salicylaldehyde)-1,2-phenylenediimino cobalt(II); Co(salophen) has been achieved via two simple steps: firstly, the Co(salophen) precursor was precipitated from the reaction of cobalt(II) acetate and N-N′-bis(salicylaldehyde)-1,2-phenylenediimino; H2salophen; in propanol under nitrogen condition; then, cubic phase Co3O4 nanoparticles with the size of mostly 30–50nm could be produced by thermal treatment of the Co(salophen) in air at 773K for 5h. The as-synthesized products were characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and scanning electronic microscopy (SEM). These results confirm that the resulting oxide was pure single-crystalline Co3O4 nanoparticles. The optical property test indicates that the absorption peak of the nanoparticles shifts towards short wavelength, and the blue shift phenomenon might be ascribed to the quantum effect. The hysteresis loops of the obtained samples reveal the ferromagnetic behaviors the enhanced coercivity (Hc ) and decreased saturation magnetization (Ms ) in contrast to their respective bulk materials.
Nb2O5-carbon nanocomposite is synthesized through a facile one-step hydrothermal reaction from sucrose as the carbon source, and studied as an anode material for high-performance lithium ion battery. The structural characterizations reveal that the nanocomposite possesses a core-shell structure with a thin layer of carbon shell homogeneously coated on the Nb2O5 nanocrystals. Such a unique structure enables the composite electrode with a long cycle life by preventing the Nb2O5 from volume change and pulverization during the charge-discharge process. In addition, the carbon shell efficiently improves the rate capability. Even at a current density of 500 mA·g−1, the composite electrode still exhibits a specific capacity of ∼100 mAh·g−1. These results suggest the possibility to utilize the Nb2O5-carbon core-shell composite as a high performance anode material in the practical application of lithium ion battery.
Abstract As an introduction to this book, a variety of semiconductor gas sensors is presented. They are classified into five types, according to the transducers used: resistor, diode, MIS (metal–insulator–semiconductor) capacitor, MIS FET (metal–insulator–semiconductor field-effect transistor), and oxygen concentration cell. The structure, working principle, and sensing mechanism are described for each type. As the only type successfully existing on the market at present, the resistor is allotted considerably more space than the alternative semiconductor gas sensors, with experimental knowledge and the theory of gas response described in detail. The receptor function of metal oxides recently found in resistors is also of critical importance in other types incorporating the same oxides; the contact potential generated between oxide and metal is likely a main origin of the gas response of those devices. Finally, observations on the prospects for and problems with semiconductor gas sensors are made.
The surface chemistry of graphite and intermetallic AlSb has been studied by XPS (X-ray photoelectron spectroscopy) in a Li-ion battery context using LiPF6 in EC/DEC as electrolyte. The main results for graphite are as follows: the SEI (solid electrolyte interphase) is different for the lithiated state after 3 cycles (0.01V) compared to the delithiated state (1.5V); after 50 cycles the SEI is thicker; there are more Li2CO3 or semi-carbonates on the surface of the delithiated sample (1.5V) than on the lithiated sample (0.01V); LiF is continuously formed during the first cycles but a steady state is reached after 50 cycles; a new peak in the C 1s spectra indicating a fluorine-containing compound is found at high photon energies (292eV). The main results for AlSb are as follows: the SEI is different for the lithiated state (0.01V) compared to the delithiated state (1.2V) after 3 cycles; after 50 cycles the surface layer thickness is slightly larger but significantly thinner than for graphite; contrary to graphite, more Li2CO3 or semi-carbonates are found on the surface of the lithiated sample; also here a new peak indicating a fluorine-containing compound is found in the C 1s spectra at 292eV. The general result is that the SEI has many similar features between graphite and AlSb but also important differences. The carbonaceous layer is dynamically shifting in chemical composition during cycling for both samples.
Chemotherapy-induced peripheral neuropathy (CIPN) is a prominent side effect of the treatment of cancer. Despite this frequent complication, there has been no comprehensive review and quality appraisal of CIPN assessments. The purpose of this study is to provide a definitive quality appraisal of CIPN assessment strategies for clinical use.
This research studies the low carbon transition of the electric power sector in China using a multi-level perspective (MLP) of niches, socio-technical regime, and landscape, as well as literature on innovation systems. Three lines of thought on transition process are integrated in the paper to probe the possible transition pathways in China. A MLP analysis is presented to understand the current niches, regime, and landscape of China’s power sector. A brief analysis on the future macroscopic socio-economic transition in the process of industrialization, urbanization, and modernization of Chinese society and its implication on power landscape are depicted to prove the urgency and magnitude of transition in China and why systematic transition management is needed. Five transition pathways, namely reproduction, transformation, substitution, reconfiguration, de-alignment/re-alignment, and reconfiguration, with their possible technology options are presented. The paper goes further to propose an interactive framework for managing the transition to a low carbon energy system in China. Representative technology options are appraised by employing innovation theory to indicate the logic of policymaking within the framework. Institutional gaps in realizing the transition are also addressed. The work presented in the paper will be useful in informing policy-makers and other stakeholders and may provide references for power sector transition management in other countries.