batterydata/paper-abstracts huggingface dataset:
Implantable glucose fuel cells are a promising approach to realize an autonomous energy supply for medical implants that solely relies on the electrochemical reaction of oxygen and glucose. Key advantage over conventional batteries is the abundant availability of both reactants in body fluids, rendering the need for regular replacement or external recharging mechanisms obsolete. Implantable glucose fuel cells, based on abiotic catalysts such as noble metals and activated carbon, have already been developed as power supply for cardiac pacemakers in the late-1960s. Whereas, in vitro and preliminary in vivo studies demonstrated their long-term stability, the performance of these fuel cells is limited to the μW-range. Consequently, no further developments have been reported since high-capacity lithium iodine batteries for cardiac pacemakers became available in the mid-1970s. In recent years research has been focused on enzymatically catalyzed glucose fuel cells. They offer higher power densities than their abiotically catalyzed counterparts, but the limited enzyme stability impedes long-term application. In this context, the trend towards increasingly energy-efficient low power MEMS (micro-electro-mechanical systems) implants has revived the interest in abiotic catalysts as a long-term stable alternative. This review covers the state-of-the-art in implantable abiotically catalyzed glucose fuel cells and their development since the 1960s. Different embodiment concepts are presented and the historical achievements of academic and industrial research groups are critically reviewed. Special regard is given to the applicability of the concept as sustainable micro-power generator for implantable devices.
The rise in disability due to back pain has been exponential with escalating medical and societal costs. The relative contribution of individual prognostic indicators to the pattern of recovery remains unclear. The objective of this study was to determine the prognostic value of demographic, psychosocial, employment and clinical factors on outcome in patients with low back pain
The 21st conference in this series was held in Newton, Massachusetts towards the end of 2003. Here Edward Gobina, of the Centre for Process Integration & Membrane Technology at Robert Gordon University in Aberdeen, Scotland provides not only an overview of the presentations, which covered a range of technologies and applications, but also highlights some of the latest developments, and market and research trends in the membrane industry.
Metallic Li anodes are key to reaching high energy densities in next-generation solid-state batteries, however, major problems are the non-uniform deposition of Li at the interface and the penetrative power of Li metal during operation, which cause failure of the ceramic electrolyte, internal short-circuits and a premature end of battery life. In this work, we explore the anode-electrolyte interface instability of a Li metal-garnet electrolyte system during Li electrodeposition, and its implications for mechanical fracture, Li metal propagation, and electrolyte failure. The degradation mechanism was followed step-by-step during in-operando electrochemical cycling using optical and scanning electron microscopy. High amounts of Li electrodeposition in a localized zone of the interface lead to ceramic fracture followed by an electrode-to-electrode electrical connection via a conductor Li metal filament. This work enables deeper understanding of battery failure modes in all-solid-state batteries containing a ceramic electrolyte membrane.
We have synthesized three dimensional architectural α–MnO2/RuO2 hybrid nanostructures with three different compositions of (75:25), (69:31) and (50:50) by hydrothermal approach and evaluated their bifunctional electrocatalytic activity for Li–O2 battery applications. The morphology of the α–MnO2/RuO2 nanostructures changed from sharp sea urchins to solid nanospheres with increasing RuO2 content in the composition. The variations observed in physical, structural, morphological and electrochemical properties were characterized with respect to the MnO2/RuO2 concentrations by step by step analyses. MnO2 exhibited better ORR catalytic activity, while RuO2 revealed superior OER catalytic activity. Among the concentrations investigated, α–MnO2:RuO2 (75:25) exhibited superior catalytic activity for oxygen reduction and evolution reactions in aqueous media. This excellent catalytic activity logically led us to apply it as air-cathode catalyst in Li–O2 cell, which produced a maximum capacity of >8100mAhg−1 with high columbic efficiency and cyclability. The superior performance of the hybrid nanostructure is mainly attributed to its structural and compositional design which favors the electrochemical activity. Based on a careful investigation on the structural characterizations, the growth mechanism of the 3D nanostructured α–MnO2/RuO2 mixed oxides is discussed in detail.
Capacity fading of a commercial 18650 LiFePO4/graphite cell was investigated at different temperatures (25, 40, 50 and 60°C) until 30% of its capacity was lost. Capacity decrease of the cell is in linear relationship with cycle number and the slope of the capacity-fading line is increased by elevating temperature. The capacity-fade mechanisms were investigated by using a combination of electrochemical, structural and inductively coupled plasma (ICP) techniques. Lithium inventory loss was found to be the main cause for the capacity loss. At the end of the cycling test, the amount of lithium precipitated on the graphite anode surface was determined. Most of the consumed lithium is found on the graphite anode, especially at high temperature condition, illustrating that the majority of lithium loss was ascribed to the side reactions at the graphite anode/electrolyte interface. Fe deposition at the graphite anode surface aroused from its dissolution into the electrolyte is not significant even when the cell is cycled at 50°C condition.
The paper discusses the most important areas of application of power electronics arrangements in the Polish electrical power system; especially in the distribution system. The examples presented demonstrate both the need for and the purpose of further research and its applications in these fields, as well as indicating the direction of future research, with special consideration given to the research required in Poland. The proposed practical solutions for power electronics arrangements, either dedicated or capable of adaptation to the distribution systems, illustrate the ability to use the potential of Polish national research-development units.
The past few years have witnessed an explosive popularity of mobile services, especially in the form of smart phone applications. To cope with the limited batteries and computational capacities of mobile devices, prior studies suggest to deploy service instances in clouds for accomplishing most of the computation-intensive tasks. Service composition, which compensates for the simplicity of single service, is an effective way to utilize the plentiful services on the clouds all over the world. In this paper, we focus on the problem of service instance selection with service instance replica limitation constraint. The objective is to select the optimal set of service instances, which composes the integrated service and brings out the optimal QoS (quality of service), in terms of service response time. To characterize the problem, we establish a new QoS model, which considers the comprehensive quality over all users, not just for any single user or service instance. We prove that the problem is NP-hard, since many functionally equivalent service instances spread all over the distributed clouds. To address the problem, we classify the problem into three cases, including two special cases and the general case. We present two effective heuristic algorithms to determine the service instances selection for the two special cases, which are still NP-hard. The two special cases provide empirical bounds for the general case. We propose an algorithm that simulates a vote procedure for the users in the general case. The selected service instances, which come from the vote procedure, can satisfy a majority of users. We conduct extensive simulations for all of the algorithms. The simulation results show that our algorithms work efficiently on service response time reduction.
Solid oxide fuel cells (SOFCs) are potentially the most efficient and cost-effective solution for the utilization of a wide variety of fuels beyond hydrogen. One of the chief obstacles to true fuel flexibility lies in anode deactivation by coking as well as a limited mechanistic understanding of coking and its prevention. Here we report Raman spectroscopic mapping and monitoring of carbon deposition on SOFC anode surfaces under both ex situ and in situ conditions. Carbon mapping was successfully demonstrated with a model Ni–YSZ electrode exposed to a CH4-containing atmosphere at high temperature (625 °C), while carbon deposition over time in a wet C3H8 atmosphere was directly monitored on a similar anode system as well as a BaO-modified system. This spectroscopic technique provides valuable insight into the mechanism of carbon deposition, which is vital in achieving rational design of carbon-tolerant anode materials.
The CoO/Ti3C2 composite is prepared via a facile hydrothermal route followed by calcination, of which the morphology and the microstructure are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). CoO nanoparticles with the diameter of 10–20 nm are uniformly coated on the surface of Ti3C2 nanosheets, which increases the surface areas and prevents the aggregation of CoO. In addition, the CoO/Ti3C2 composite as an anode material for lithium-ion batteries (LIBs) demonstrates a higher initial discharge capacity of 1389 mAh g−1 with a columbic efficiency of 61% at 100 mAh g−1. The reversible capacity can remain about 313 mAh g−1 after 100 cycles, which is much higher than that of the pure Ti3C2. The present results indicate that CoO/Ti3C2 composite has a potential application in the anode of LIB.
Attributional style models of depression in adults (Abramson et al. 1989, 1978) have been adapted for use with children; however, most applications do not consider that children’s understanding of causal relations may be qualitatively different from that of adults. If children’s causal attributions depend on children’s level of cognitive development, then support for attributional models of depression in young people will vary with cognitive development. In this paper, a new measure of cognitive development, the Peabody Causal Reasoning Test (PCRT), is introduced to assess children’s understanding of ability versus effort, task difficulty, and luck as causal factors. Analyses revealed that in 8- to 16-year-old children, failure to control for level of cognitive development suppressed empirical support for cognitive diathesis-stress models of depression. Statistically controlling for measures of cognitive development strengthened support for this model.
Ternary metal oxides based on nickel and cobalt are synthesized on Ni foam as the energy storage electrode using a nickel precursor-free hydrothermal reaction with incorporation of Mo, Fe, Cu, Zn, and Al, aiming to enhance the electrical conductivity and generate more Faradaic reactions via multiple transition states of metals. Ni foam is acted as the current collector and the Ni ion source to reduce precursor cost and enhance contact between electrocapacitive material and substrate. Benefit from the large surface area and vertically growing direction, the nickel cobalt copper oxide electrode shows the highest areal capacitance of 2.28 F cm-2 at 5 mA cm−2 among ternary metal oxide electrodes. An asymmetric supercapacitor based on the nickel cobalt copper oxide positive electrode and an activated carbon negative electrode also shows an areal capacitance of 917 mF cm-2 at 5 mA cm−2, a potential window of 1.5 V, and an areal capacitance retention of 83.2% after 10,000 cycles charge/discharge process. Using the low-cost and effective nickel precursor-free synthesizing method to fabricate novel ternary metal oxides for asymmetric supercapacitors is successfully realized in this work. Further improvements based on this concept is worthy to investigate for achieving more efficient asymmetric supercapacitors for efficient energy storage.
The lithium ion battery electrolytic solvent, ethylene carbonate:di ethylene carbonate (EC:DEC), influences the exfoliation of semi exfoliated graphite oxide (srGO) further, to promote the better disperstion of Fe3O4 and to enhance the material performance. The composite, semi exfoliated reduced graphite oxide-Magnetite (srGO–Fe3O4) has been prepared using homogeneous co-precipitation method with the aid of microwave oven. The microwave has been introduced to reduce GO and improve the interstitial crystallisation of Fe3O4. srGO–Fe3O4 composite material has been subjected to structural and electrochemical characterization to evaluate their structure and aptness as a possible anode material for lithium ion batteries. srGO–Fe3O4 composite in the 1st cycle demonstrate a better charge capacity of ∼994 mAhg−1 at 75 mA g−1 in the potential range 0.01–3.0 V. Besides, interestingly the cyclability at higher rate (300 mA g−1) is encouraging and demonstrates increased in capacity than the initial over the studied 100 cycles. Thereby, providing proof for the exfoliation driven by EC:DEC in graphitic lamella and by assisting in the expansion of its reaction sites for the better insertion and desersion of lithium ion during cycling. This exfoliation and distribution of particles over srGO matrix has made evident from the FESEM images and Raman shift analysed for the cycled electrode.
In the present investigation, we have successfully assembled symmetric supercapacitor device based on cobalt hydroxide [Co(OH)2] thin film electrodes using 1M KOH as an electrolyte. Initially, potentiodynamic electrodeposition method is employed for the preparation of Co(OH)2 thin films onto stainless steel substrate. These films are characterized for structural and morphological elucidations using X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The XRD reveals formation of β-Co(OH)2 material with hexagonal crystal structure. The SEM images show formation of nanoflakes like microstructure with average flake width 100nm. Electrochemical characterizations of Co(OH)2 based symmetric supercapacitor cell are carried out using cyclic voltammetry, charge–discharge and electrochemical impedance spectroscopy (EIS) techniques. In the performance evaluation the maximum values of specific capacitance, specific energy and specific power are encountered as 44Fg−1, 3.96Whkg−1 and 42kWkg−1. The value of equivalent series resistance (ESR) is estimated as 2.3Ω using EIS.
The rapid thermal annealing (RTA) process was employed to obtain crystalline LiCoO2 thin films. XRD analyses of the LiCoO2 thin film show increased crystallinity with an increase in the RTA time. The Auger electron spectroscopic analysis of the LiCoO2 film strongly suggests that the RTA process is more advantageous to obtain a stable inter layer between the substrate and the deposited film and between each deposited layer than the conventional annealing process. All-solid-state thin film cells composed of Li/lithium phosphorous oxynitride (Lipon)/LiCoO2 systems were fabricated using the LiCoO2 cathode treated with RTA. The optimum condition of RTA would be 900s at 650°C, which exhibited a good rate capability for high power applications. Two cells were connected in parallel to obtain a higher discharge current, and they showed a specific capacity of 38.4μAhcm−2 μm−1 even at a 25C rate (current density: 7.96mAcm−2).
The conductivity of a lyotropic liquid crystal medium (LLC) consisting of 50:50wt.% Brij 56® and 0.5M aqueous KCl was found to be five times lower than the purely aqueous solution. Electrochemical properties of potassium hexacyanoferrate(II)/(III) and ferrocene/ferricinium in the LLC were examined by cyclic voltammetry and chronoamperometry on platinum foil and microdisk electrodes. The hexacyanoferrate showed reversible redox behaviour under diffusion control with a diffusion coefficient of 0.5–1.0×10−6 cm2 s−1, up to 14 times lower than in water. Ferricinium reduction, while complicated in water by precipitation of ferrocene, showed solution behaviour and normal diffusion control in the liquid crystal. Effective diffusion coefficients of ferrocene and ferrocinium in the lyotropic liquid crystal were found to be further reduced to 4–5×10−8 cm2 s−1. The lower diffusion coefficients compared with those in liquid solvents were attributed to restricted mobility and channel size effects in the LLC. The results are relevant to the design of electrochemical syntheses using LLC as nanostructured templates or as amphiphilic solvents.
ZnO–ZnCo2O4 hybrid hollow microspheres are successfully produced via an annealing process of the pre-fabricated zinc–cobalt citrate hollow microspheres in air. ZnO and ZnCo2O4 have homogeneous distribution within the whole hollow microspheres. The gained hybrid hollow microspheres deliver outstanding lithium storage properties when utilized as the anode material in lithium ion batteries. A high reversible capacity of 1199mAhg−1 can be retained after 200 cycles. The exceptional electrochemical properties of the hybrid hollow microspheres are ascribed to the synergetic effect between ZnO and ZnCo2O4 nanoparticles, the catalytic effect of Co nanocrystals, the favorable hollow structures together with the nanometer-sized building blocks of hybrid microspheres.
To address the huge volume changes and unstable solid-electrolyte interface (SEI) layer during lithiation/delithiation of silicon, this paper proposes a novel ‘silicon alloy’ concept that is achieved by proposing the synthesis of Si/WSi2 via a magnesiothermic co-reduction. The WSi2 is formed by absorbing the heat generated from magnesiothermic co-reduction, which increases the conductivity and acts as the mechanical backbone to buffer the volume change. Thereby, Si/WSi2 displays a superior specific charge capacity of 2678 mAh g−1 at the current density of 100 mA g−1 as an anode material, with the capacity retention of 84% after 40 cycles. Moreover, it shows excellent rate capability of 997 mAh g−1 at the current density of 10 A g−1 and excellent cycling performance up to 100 cycles at the current density of 1 A g−1.
Electrochemical nano technology (ENT) is a promising field growing in strong connection with electrochemical microsystem technology (EMT). Some principles of EMT like characterization and localization of reactions can be transferred to ENT. Some other principles like mechanical motion, quantum effects or microfluidics differ and have to be separately discussed. Properties of the nanocell, the smallest electrochemical two-electrode cell, are discussed as example of a special tool of ENT. It is useful for the preparation of nano-scaled metal-insulator-electrolyte-structures (MIE-structures). The role of the EMT number for field-induced localizations is discussed with the Si/SiO2-system as an example. Lateral metal-insulator-metal-structures (MIM-structures) are prepared in the nanocell with the system Nb/Nb2O5/H2O as an example.
Gelatin, a natural biological macromolecule, was successfully used as a new binder in place of poly(ethylene oxide) (PEO) in the fabrication of the sulfur cathode in lithium–sulfur batteries. The structure and electrochemical performance of the two types of sulfur cathodes, with gelatin and PEO as binders, respectively, were compared in 1M LiClO4 DME/DOL (V/V=1/1) electrolyte. The results showed that the gelatin binder had multifunctional effects on the sulfur cathode: it not only functioned as a highly adhesive agent and an effective dispersion agent for the cathode materials, but also an electrochemically stable binder. The gelatin binder-sulfur cathode achieved a high initial capacity of 1132mAhg−1, and remained at a reversible capacity of 408mAhg−1 after 50 cycles, all of which were better than with the PEO binder-sulfur cathode under the same conditions.
In situ high-energy X-ray diffraction was carried out to investigate the structural transformation of lithium cobalt oxides during the solid-state synthesis. Two allotropic phases were observed during the synthesis process; Li2Co2O4 with a spinel structure was formed within the temperature window between 450 °C and 650 °C, beyond which Li2Co2O4 was converted to its hexagonal counterpart, layered LiCoO2, through a cation exchange between Li and Co. In electrochemical tests, the Li2Co2O4 was estimated to have a very low reversible capacity, ∼20 mAh g−1, and a high initial irreversible capacity loss of about 80 mAh g−1. An interfacial phase between layered LiCoO2 domain and spinel Li2Co2O4 domain was also identified by ex situ high-resolution X-ray diffraction.
Over the years, there has been a great deal of research conducted on the role of tasks in second language acquisition, but less is known about how tasks affect listening comprehension. The present study is an investigation of the impact of task complexity on Iranian EFL learners’ listening comprehension across aptitude. For this purpose, data was collected from two EFL classes including 70 Iranian EFL learners (F=45, M=25). Test-takers’ aptitude was assessed by Oxford language aptitude test. Two task dimensions, i.e., planning time and prior knowledge, each under two +/complex & -/simple conditions (i.e., task manipulated for complexity and simple task) were used in test-takers’ listening performance. Descriptive statistics, ANOVA test were utilized to analyze the listening performance of the participants. The results of the study indicated that the subjects’ performance was better under simple conditions than complex ones for all task dimensions. Moreover, the results didn’t show any significant difference among performance of the different aptitude levels under both simple and complex conditions. In short, this study didn’t show any considerable effect of aptitude on task complexity.
Memory and language operate in synergy. Recent literature stresses the importance of memory functioning in interpreting language deficits. Two groups of 50 children each, ages 8–12 were studied. The first group included children with specific language impairment, while the participants in the second group were typically developing children. The two groups, which were matched on age, nonverbal intelligence and varied significantly in verbal ability were examined, using a test battery of four memory functioning (phonological, working and long-term memory) and five mental verb measures. The statistical analyses indicated that the two groups differed significantly in all language and memory measures; a logistic regression analysis revealed that within each main group existed nested subgroups of different developmental patterns with working and long-term memory measures as the most robust discriminate markers of classification. Language impaired children had more difficulties in the acquisition of mental verbs because they are less able to process and store phonological information in working memory and long-term lexicon.