batterydata/paper-abstracts huggingface dataset:
To improve the electrochemical activity of polyacrylonitrile (PAN)-based electrospun carbon nanofibers (ECNFs) toward vanadium redox couples, the multi-wall carbon nanotubes (CNTs) and Bi-based compound as electrocatalyst have been embedded in the ECNFs to make composite electrode, respectively. The morphology and electrochemical properties of pristine ECNFs, CNTs/ECNFs and Bi/ECNFs have been characterized. Among the three kinds of electrodes, the CNTs/ECNFs show best electrochemical activity toward VO2+/ VO 2 + redox couple, while the Bi/ECNFs present the best electrochemical activity toward V2+/V3+ redox couple. Furthermore, the high overpotential of hydrogen evolution on Bi/ECNFs makes the side-reaction suppressed. Because of the large property difference between the two composite electrodes, the CNTs/ECNFs and Bi/ECNFs are designed to act as positive and negative electrode for vanadium redox flow battery (VRFB), respectively. It not only does improve the kinetics of two electrode reactions at the same time, but also reduce the kinetics difference between them. Due to the application of asymmetric electrodes, performance of the cell is improved greatly.
In this work, the effects of Co substitution for Ni on the microstructures and electrochemical properties of Ti0.8Zr0.2V2.7Mn0.5Cr0.6Ni1.25−x Co x Fe0.2 (x =0.00–0.25) alloys were investigated systematically by XRD, SEM and electrochemical measurements. The structural investigations revealed that the main phases of all of the alloys were the C14 Laves phase in a three-dimensional network and the V-based solid solution phase with a dendritic structure. The lattice parameters and unit cell volumes of the two phases gradually increased with the increase of Co concentration. The relative abundance of the C14 Laves phase slightly increased from 47.3% to 49.6%, accordingly that of the V-based solid solution phase decreased, with the increase of x from 0.00 to 0.25. The crystal grain of the V-based solid solution phase was obviously refined after Co substitution. The electrochemical investigations showed that the proper substitution of Co for Ni improved the cycling durability of the alloy electrodes mainly due to the suppression of both the pulverization of the alloy particles and the dissolution of the main hydrogen absorbing elements (V and Ti) into the KOH solution. The cycling stability of the alloy electrode with x =0.1 was 79.8% after 200 cycles. However, the maximum discharge capacity (C max) was decreased from 340.5 to 305.6mAhg−1, and the high rate dischargeability (HRD) gradually decreased from 66.8% to 55.0% with increasing x from 0.00 to 0.25.
A new primary school Physical Education (PE) program was launched in 2007 in Turkey, in which the development of health-related physical fitness is one of the most important goals. The purpose of the present study was to investigate the effects of inquiry-based learning model on the fitness components and fitness knowledge test in sixth grade students during the six-week health-related fitness program. Forty-six children from the sixth grade, aged between 11 to 12 years, participated in the study. The experimental group consisted of 23 children who participated in the program held one day a week for an 80-minute session, which was allotted for the Physical Education in the school. The control group (n=23) participated in the routine Physical Education program in the curriculum. One week before and after the study, a physical fitness test was employed in order to assess the subjects and controls. Health-related fitness components (cardio- respiratory endurance, abdominal strength and endurance, flexibility, and body composition) were assessed with the Fitnessgram test battery.
MnO2 has been demonstrated to be an effective catalyst for Zn-air batteries, but suffers from cripplingly low cell performance due to its limited electrical conductivity. In this work, we report a facile process for preparing the MnO2/C air cathode by directly anchoring the MnO2 onto Ketjen Black (KB) via an in-situ redox reaction. It is demonstrated that a Zn-air battery installed with the proposed MnO2/KB air cathode outperforms that installed with a commercial Pt/C cathode. Specifically, the MnO2/KB cathode presents a more positive ORR onset potential and a larger current density compared with that of the Pt/C cathode. Under ambient air, the prepared MnO2/KB air cathode allows the battery to reach a peak power density of 133.17mWcm−2 when operated at a current density of 188.51mAcm−2, which is among the highest values in the literature. More impressively, the battery installed with the proposed cathode can be operated at a high current density of up to 100mAcm−2 with a voltage discharge plateau larger than 1.0V. These results indicate that the MnO2/KB electrode offers a promising option for both alkaline fuel cells and metal-air batteries.
In this chapter we diverge from the IBOC protocol stack as it is described in the NRSC-5 standard, delving into a discussion of the end points of the IBOC system: transmission system inputs at the starting end, and receivers at the destination. Chapters 3 through 11 addressed the IBOC protocol stack through the NRSC-5 standards documents themselves. Chapters 12 and 13 touched on how the IBOC waveform—the physical layer of the model—must be treated to radiate over the air properly. This chapter looks first at the IBOC broadcast facility (we'll call it Transmission), then at the IBOC receiver (Reception).
To understand the underlying factors affecting the seasonal variation of the methane concentration in a cool temperate freshwater marsh vegetated with Carex lasiocarpa in the Sanjiang Plain of northeast China, we measured methane emission from, and the concentrations of methane, dissolved organic carbon (DOC) and acetate in, water samples taken from the standing water surface to the top of the gley soil layer in the C. laisocarpa marsh, before and after plants were covered with a black cloth at the three growing stages of June, July and August 2002. The methane oxidation rate was also measured in situ by applying acetylene, a methane oxidation inhibitor, to whole plants, and the methane production rate in water sampled in June and July was measured via the anaerobic incubation in the laboratory. The methane production rate in water samples was significantly correlated with acetate concentration rather than DOC concentration, whereas the mean acetate concentration in water samples was higher in June than in July and August. Hence, the low methane concentration in June did not result from a lack of acetate for methane production. The mean methane and DOC concentrations in water samples were enhanced by 22.3 and 31.1% in June, 2.1 and 5.0% in July, and 3.4 and 15.2% in August, respectively, after plants were covered with a black cloth. The methane oxidation rate and redox potential in the freshwater marsh decreased from June to July or August. These results suggest that there was more oxygen in the rhizome and rhizosphere in June than in July and August, which not only accentuated methane oxidation but also reduced methane production. Therefore, the high methane concentration in water in July and August could be ascribed to both an increase in temperature and a decrease in redox potential or oxygen concentration in the rhizosphere.
Graphene has been reported with record-breaking properties which have opened up huge potential applications. Considerable amount of researches have been devoted to manipulating or modify the properties of graphene to target a more smart nanoscale device. Graphene and carbon nanotube hybrid structure (GNHS) is one of the promising graphene derivate. The synthesis process and the mechanical properties are essential for the GNHS based devices. Therefore, this review will summarise the recent progress of the highly ordered GNHS synthesis/assembly, and discuss the mechanical properties of GNHS under various conditions as obtained from molecular dynamics simulations.
After some general remarks, this paper presents a brief overview of the relationships among science technology and politics. This is followed by an examination of the seven most important technological revolutions of the past five centuries, laying a foundation for consideration of recent trends in US Research and Development and our investments within them. The paper concludes with an examination of the impact of President George W. Bush’s proposed budget for science and technology in the 2002 fiscal year. This paper is based on the Sheffield Lecture delivered by Dr. Bromley at Yale University, March 22, 2001.
A new thermally stable ternary mixture composed of ethylene carbonate, γ-butyrolactone and methyl propionate (1: 1: 1 by weight), named EGM, is proposed for use as an electrolyte with the new salt LiTDI at a concentration of 1 mol L−1. The EGM mixture has many advantages over the classical binary mixture EC/DMC (1:1 by weight) when LiTDI is used as single salt: (i) it remains liquid from −60 °C to 130 °C, (ii) it exhibits a higher conductivity (8.5 mS cm−1 vs. 6.8 mS cm−1 at 25 °C), (iii) a lower viscosity (2.4 mPa s vs. 2.8 mPa s at 25 °C) and, (iv) allows a better dissociation of LiTDI (37% vs. 31%). Cycling tests were performed using graphite/Li and LiNi1/3Mn1/3Co1/3O2 (NMC)/Li half-cells as well as graphite/NMC full cells. It was shown that this electrolyte provides fair capacity retention for both the graphite and the NMC electrode at high C rates: up to 10C for graphite/Li half-cells and up to 6C for NMC/Li half-cells. The graphite//LiTDI-EGM//NMC full cell was able to sustain more than 800 cycles with a capacity retention of 70%, which is more than what was obtained in the same conditions with a graphite//LiPF6-EC/DMC//NMC cell (560 cycles). The impact on the discharge capacities of high (60 °C) and low (−20 °C) applied temperatures is also discussed herein.
Composite polymer electrolyte (CPE) membranes, comprising poly(vinylidene fluoride–hexafluoropropylene) (PVdF–HFP), aluminum oxyhydroxide (AlO[OH] n ) of two different sizes 7μm/14nm and LiN(C2F5SO2)2 as the lithium salt were prepared using a solution casting technique. The prepared membranes were subjected to XRD, impedance spectroscopy, compatibility and transport number studies. Also Li Cr0.01Mn1.99O4/CPE/Li cells were assembled and their charge–discharge profiles made at 70°C. The incorporation of nanofiller greatly enhanced the ionic conductivity and the compatibility of the composite polymer electrolyte. The film which possesses a nanosized filler offered better electrochemical properties than a film with micron sized fillers. The results are discussed based on Lewis acid–base theory.
This paper presents a fuzzy logic model of regenerative braking (FLmRB) for modeling EVs’ regenerative braking systems (RBSs). The model has the vehicle’s acceleration and jerk, and the road inclination as input variables, and the output of the FLmRB is the regeneration factor, i.e. the ratio of regenerative braking force to the total braking force. The regeneration factor expresses the percentage of energy recovered to the battery from braking. The purpose of the FLmRB development is to create realistic EV models using as least as possible manufacturers intellectual property data, and avoiding the use of EV on-board sensors. To tune the model, real data was gathered from short and long-distance field tests with a Nissan LEAF and compared with two types of simulations, one using the proposed FLmRB, and the other considering that all the braking force/energy is converted to electric current and returned back to charge the battery (100% regeneration). The results show that the FLmRB can successfully infer the regenerative braking factor from the measured EV acceleration and jerk, and road inclination, without any knowledge about the EV brake control strategy.
The potential transient during pulse discharge is studied for ultra-thin silver oxide electrodes with special attention to the potential valleys. The potential valley appears in different ways depending on the history of charge and discharge undergone by the electrode and is attributed to highly resistive Ag2O layers. The latter may exist on the surface of silver substrate (current collector) or inside the particles of active material. Moreover, the resistive Ag2O layer may be partially reduced during current pulses and partially restored during pulse intervals, leading to complicated potential responses to the pulse discharge. To prevent the annoying potential valley, the silver electrode is suggested to be charged to an extent below the full conversion of Ag to Ag2O.
Poly(acrylonitrile–butyl acrylate) gel polymer electrolyte was prepared for lithium ion batteries. The preparation started with synthesis of poly(acrylonitrile–butyl acrylate) by radical emulsion polymerization, followed by phase inversion to produce microporous membrane. Then, the microporous gel polymer electrolytes (MGPEs) was prepared with the microporous membrane and LiPF6 in ethylene carbonate/diethyl carbonate. The dry microporous membrane showed a fracture strength as high as 18.98MPa. As-prepared gel polymer electrolytes presented ionic conductivity in excess of 3.0×10−3 Scm−1 at ambient temperature and a decomposition voltage over 6.6V. The results showed that the as-prepared gel polymer electrolytes were promising materials for Li-ion batteries.
PV-Trombe wall (PVTW) is a novel version of Trombe-wall. Photovoltaic cells on the cover glazing of the PVTW can convert solar radiation into electricity and heat simultaneously. A window on the south façade can also introduce solar heat into the room in the winter season. Experiment has been conducted to study the temperature field of a building with both southern facing window and the PVTW. A dynamic numerical model is developed for the simulation of the whole building system. The temperature of the indoor air is found to be vertically stratified from the measurement. The nodal model is adopted to calculate the temperature profile in the room. The simulation results are in good agreement with the experimental data. The different south façade designs affect the thermal efficiency of the PVTW significantly from the numerical simulation. With a southern facing window, the thermal efficiency of the PVTW is reduced by 27% relatively. The increase of PV coverage on the glazing can reduce the thermal efficiency of the TW by up to 17%. By taking account of electric conversion, the total efficiency of solar utilization is reduced by 5% at most while the glazing is fully covered with PV cells. The electric conversion efficiency of the PVTW achieves 11.6%, and is slightly affected by south façade designs.
The MedStream Programmable Infusion Pump, an intrathecal pump indicated for the treatment of chronic intractable pain and severe spasticity (CE-mark) or severe spasticity (US), has a highly accurate medication delivery (within 10 % of the programmed flow rate) and is certified for use in 3-Tesla magnetic resonance imaging systems (conditional). Performance of the telemetric link between external control-unit and implanted pump was assessed in sheep (in vivo) up to 26 weeks, resulting in 1040 communication sessions. The telemetric communication envelope (communication distance and maximum antenna tilt angles) and communication duration were characterized in an in vitro test. Capacitance measurements of the piezoelectric actuator of the valve, valve flow rates, and leak rates were measured in an in vitro cyclic accelerated aging test to assess reliability of the valve over 6,200 k cycles. The pump was well tolerated in vivo; all communication sessions between control-unit and pump were successful (P = 6.889 × 10−14). Mean communication distance between pump and control-unit was 3.8 cm, with the maximum antenna tilt angles being 40° (θy) and 50° (θx) for all test cases; the maximum communication duration was 5.5 s. Capacitance measurements, flow rates, and leak rates were within ±10 % range up to 6,200 k cycles corresponding to approximately 10 times the valve cycles over the specified service life of the pump (8 years), except for one flow-rate value, which can be explained by the measurement setup. These results demonstrate the reliability of the telemetry link and piezoelectric valve system of the MedStream Programmable Infusion Pump.
Previous studies have demonstrated impairments in attention, memory and executive functions in euthymic bipolar patients (BP) as well as their unaffected first-degree relatives, albeit in an attenuated form. Subsequently, cognitive deficits are discussed as a possible endophenotype of bipolar disorder. However, recent studies showed that only a subgroup of BP shows cognitive impairments. The aim of the present study was to investigate cognitive functioning in relatives compared to BP, to find out if the differentiation in a cognitive deficit vs. non-deficit subgroup is valid for relatives of BP, too. Therefore, the performance of 27 unaffected relatives of BP, 27 euthymic BP and 27 HC were compared using a neuropsychological test battery. The results showed that BP exhibited a reduced psychomotor speed and deficits in working memory compared to relatives and HC. Relatives performed significantly slower (psychomotor speed) as compared to HC (p = 0.024); performance in the other test measures lie between BP and HC. Furthermore, a detailed evaluation of the data indicated that only subgroups of BP and relatives exhibited cognitive impairments in the implemented tests. However, the deficit and non-deficit groups did not differ in sociodemographic and clinical variables from each other, possibly due to the small sample size. In conclusion, our results suggest that reduced psychomotor speed could serve as a potential endophenotype for bipolar disorder which should be investigated along the developmental trajectory of this disorder, also to examine whether abnormalities therein precede onset of the first mood episode. Furthermore, the division of relatives into subgroups aids in the identification of stable trait markers and high-risk bipolar groups and could enable early prevention strategies. As to that more research using distinct and homogeneous subgroups is necessary.
Two types of NiO–Li2CO3 nanocomposite electrodes have been prepared for the electrochemical decomposition studies. The thin film electrode with a thickness of 225 nm and grain size around 5–8 nm is prepared by a pulsed laser deposition method. The powder sample is prepared by a solution evaporation and calcination method with primary particle size in the range of 20–50 nm. Using ex situ TEM, Raman and FTIR spectroscopy and synchrotron based in situ XRD, the electrochemical decomposition of Li2CO3 phase in both types of the NiO–Li2CO3 nanocomposite electrodes after charging up to about 4.1 V vs Li+/Li at room temperature is clearly confirmed, but not in the electrode containing only Li2CO3. The NiO phase does not change significantly after charging process and may act as catalyst for the Li2CO3 decomposition. The potential of using NiO–Li2CO3 nanocomposite material as additional lithium source in cathode additive in lithium ion batteries has been demonstrated, which could compensate the initial irreversible capacity loss at the anode side.
The explosion and fire hazards associated with thermal runaway in lithium-ion (Li-ion) cells require monitoring internal temperature changes in seconds in order to ensure battery safety. Among the various techniques for internal temperature cell determination, only impedance-based temperature monitors have the characteristics necessary for rapid response. Here we discuss a novel method for prediction and prevention of thermal runaway in Li-ion batteries based on rapid (on the order of seconds) monitoring of cell impedance. The electrical impedance – a complex quantity – is represented by two real numbers, e.g., impedance amplitude and phase shift (φ). The phase shift φ at a specified frequency has a higher measurement resolution and is much less dependent on the size of Li-ion cells (Ah capacity). We demonstrate in this work emergence of characteristic changes in φ before and during a rapidly evolving thermal runaway event. We highlight the capability to predict and possibly prevent thermal runaway in a Li-ion cell by incorporating a phase-shift monitor in a battery management system.
We carried out a detailed study of the kinetics of oxidation of ferrocene (Fc) to ferrocenium ion (Fc+) in the non-aqueous lithium ion conducting electrolyte composed of a solution of 1M LiPF6 in 1:1 EC:EMC solvent mixture. This study using cyclic (CV) and rotating disk electrode (RDE) voltammetry showed that the Fc0/Fc+ redox couple is reversible in this highly concentrated electrolyte. The ferrocene and ferrocenium ion diffusion coefficients (D) were calculated from these results. In addition, the electron transfer rate constant (k 0) and the exchange current density for the oxidation of ferrocene were determined. A comparison of the kinetic data obtained from the two electrochemical techniques appears to show that the data from the RDE experiments are more reliable because they are collected under strict mass transport control. A Tafel slope of c.a. 79mV/decade and a transfer coefficient α of 0.3 obtained from analysis of the RDE data for ferrocene oxidation suggest that the structure of the activated complex is closer to that of the oxidized specie due to strong interactions with the carbonate solvents. The experiments reported here are relevant to the study of redox reagents for the chemical overcharge protection of Li-ion batteries.
The cycling performance of a silicon/carbon composite anode has been significantly enhanced by using acrylic adhesive and modified acrylic adhesive as binder to fabricate the electrodes for lithium ion batteries. The capacity retentions of Si/C composite electrodes bound by acrylic adhesive and modified acrylic adhesive are 79% and 90% after 50 cycles, respectively. These two binders are electrochemically stable in the organic electrolyte in the working window. They also show larger adhesion strength between the coating and the Cu current collector as well as smaller solvent absorption in the electrolyte solvent than polyvinylidene fluoride (PVDF). Furthermore, sodium carboxyl methyl cellulose (CMC) plays an important role on improving the properties of acrylic adhesive, which increases the adhesive strength of acrylic adhesive and improves the activation of the electrodes.