batterydata/paper-abstracts huggingface dataset:
The pH of mine impacted waters was estimated from the spectral reflectance of resident sediments composed mostly of chemical precipitates. Mine drainage sediments were collected from sites in the Anthracite Region of eastern Pennsylvania, representing acid to near neutral pH. Sediments occurring in acidic waters contained primarily schwertmannite and goethite while near neutral waters produced ferrihydrite. The minerals comprising the sediments occurring at each pH mode were spectrally separable. Spectral angle difference mapping was used to correlate sediment color with stream water pH (r 2=0.76). Band-center and band-depth analysis of spectral absorption features were also used to discriminate ferrihydrite and goethite and/or schwertmannite by analyzing the 4T1←6A1 crystal field transition (900–1000 nm). The presence of these minerals accurately predicted stream water pH (r 2=0.87) and provided a qualitative estimate of dissolved SO4 concentrations. Spectral analysis results were used to analyze airborne digital multispectral video (DMSV) imagery for several sites in the region. The high spatial resolution of the DMSV sensor allowed for precise mapping of the mine drainage sediments. The results from this study indicate that airborne and space-borne imaging spectrometers may be used to accurately classify streams impacted by acid vs. neutral-to-alkaline mine drainage after appropriate spectral libraries are developed.
In this paper, we propose a novel on-demand energy-aware routing protocol, utility-based power control routing (UBPCR), which reduces the trade-offs that arise in the other energy-aware route selection mechanisms that have recently been proposed for mobile ad hoc networks. Our approach is based on an economic framework that represents the degree of link's satisfaction (utility). With UBPCR, the utility function for any transmitter–receiver pair is defined as a measure of the link's preference regarding the signal-to-interference-plus-noise ratio (SINR), the transmit power, and the transmitter's residual battery capacity. During a route-searching process, each intermediate node between the source and the destination is executed via two consecutive phases: the scheduling phase and the transmit power control phase. The scheduling algorithm finds the proper qualified data slot for the receiving channel so that the transmissions of independent transmitters can be coordinated. The transmit power control determines the optimal power, if one exists, that maximizes the corresponding link's utility. Extensive simulations show that the UBPCR protocol can achieve incompatible goals simultaneously and fairly.
The electro-reduction of magnetite is important for many different industries. For example, it relates to the extraction of iron from iron ore and the charging of iron-based batteries. The sluggish electro-reduction reaction of magnetite affects the energy efficiency of iron extraction or the charge rate of iron-based batteries. However, what factors affecting the reduction rate is not well understood. In this study, electrochemical analysis, XRD, SEM, EDS mapping and XPS techniques are adopted to analyze the reaction, and it is proved that two factors determine the electro-reduction rate of magnetite electrode: O2− diffusion inside the particles determines the electro-reduction rate of a single particle, and the electrical resistivity of electrode determines how many magnetite particles are involved in electro-reduction simultaneously. Contact resistance between particles is the dominant part of the electrical resistance of the magnetite electrode. The function mechanism of sulfide in the reaction is also revealed: a sulfide additive can react with magnetite to form amorphous or crystal FeS at different potentials. These compounds, especially crystal FeS, coat onto the surface of magnetite particles, and bond them together. The coating and bonding can decrease contact resistance significantly, thus enhancing the electro-reduction rate of magnetite to one order of magnitude.
Imperial Racing Green is an undergraduate teaching project at Imperial College London. Undergraduate engineers have designed, built and raced hydrogen fuel cell hybrid vehicles in the Formula Zero and Formula Student race series. Imperial Racing Green has collaborated with its fuel cell partners to develop a 13kW automotive polymer electrolyte membrane fuel cell (PEMFC) system. A team of undergraduate engineers were given a relatively modest budget and less than 8 months to design and assemble an operational high-power PEMFC system. The fuel cell system was designed to provide the average power required by the team's 2011 Formula Student entry. This paper presents the team's experience of developing and testing an automotive fuel cell system for a race application and plans for its future development and integration onto the vehicle.
Using galvanostatic discharges, the electrochemical properties of fluorinated carbon nanofibers (CNF) have been investigated. Several methods of fluorination are compared, (i) direct process using a flux of pure molecular fluorine F2 (dynamic process), (ii) controlled fluorination using atomic fluorine released continuously by the thermal decomposition of a solid fluorinating agent (TbF4), and (iii) static fluorination by the filling of a closed reactor with undiluted molecular fluorine as reactive gas. Electrochemical performances of the resulting materials are compared highlighting significant improvement using the static method. The discharge potential increases from 2.27V (vs. Li+/Li°) for materials obtained by the direct route to a medium 2.40V by the static route resulting from a two steps discharge mechanism. Owing to a complete characterization of each fluorinated materials by X-ray diffraction (XRD), solid state nuclear magnetic resonance (NMR) and transmission electron microscopy (TEM), the increased average potential of fluorinated sample through the static way has been explained by the peculiar distribution of fluorine and carbon sites in the nanomaterial. Then, in order to understand the two steps discharge mechanism of the latter material, its discharge mechanism through galvanostatic measurements at different depths of discharge has been investigated in different electrolytes. The discharged materials have been studied owing to 19F MAS NMR, XRD and scanning electron microscopy characterizations. The texture and cristallinity of lithium fluoride particles are key parameters acting on the ionic diffusion of Li+ and F− ions and as a consequence on the electrochemical performances. Its high solubility in EC/PC/3DMC solvent mixture prevents from overvoltage phenomenon occurring during the discharge of fluorinated carbon nanofibers in primary lithium battery.
In this study we report the characterization of a prototype solid-state electrochromic device based on poly(ethylene oxide) (PEO)/siloxane hybrid networks doped with lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). The polymer networks prepared, designated as di-ureasils and represented as d-U(2000), were produced by a sol–gel procedure and are composed of a siliceous framework to which both ends of polyether chains containing about 40 CH2CH2O units are covalently bonded through urea linkages. Samples with compositions of 200≥ n ≥0.5 (where n is the molar ratio of CH2CH2O to Li+) were characterized by thermal analysis, complex impedance measurements and cyclic voltammetry at a gold microelectrode. Electrolyte samples were obtained as self-supporting, transparent, amorphous films and at room temperature the highest conductivity was observed with the d-U(2000)35LiTFSI composition (3.2×10−5 Ω−1 cm−1). We report the results of preliminary evaluation of these polymer electrolytes as multi-functional components in prototype electrochromic displays. Device performance parameters such as coloration efficiency, optical contrast and image stability were also evaluated. The electrolytes with n >8 presented an optical density above 0.56 and display assemblies exhibited good open-circuit memory and stable electrochromic performances.
Sulfuric acid is one of the three active materials that take part in the reactions in lead-acid batteries. As a result of the reactions of current generation and accumulation in the battery the concentration of H2SO4 in the electrolyte changes. The battery has the highest performance parameters when the variations in H2SO4 concentration on cycling are within the range from 1.10 to 1.28 specific gravity (SG). In this acid concentration range, lead dioxide has the highest electrochemical activity, lead sulfate is highly soluble, and the H2SO4 solution is most electroconductive. Acid concentration determines open circuit battery voltage. This should be taken into account when selecting the upper charging voltage limit so as to guarantee fully charged battery. Battery performance depends on the utilization coefficients of the three active materials: Pb, PbO2 and H2SO4. When the utilization of H2SO4 is higher than that of Pb and PbO2, the battery has lower initial capacity, but longer cycle life. When Pb and PbO2 are the capacity-limiting active materials, the initial capacity is high, but its life is shorter. The sulfuric acid purity is very important for normal operation of the battery and is regulated by a H2SO4 purity standard. Tests with various additives to the electrolyte (phosphoric acid, boric acid, polymer emulsions etc.) have proved that they have but limited applications. During battery cycling, vertical stratification of the H2SO4 electrolyte occurs. This creates local potential differences in height and leads to self-discharge and capacity loss of the cell. Gas evolution in the cell homogenizes the electrolyte concentration throughout the cell volume.
This study examined the effect of word level phonological knowledge on learning to read new words in Down syndrome compared to typical development. Children were taught to read 12 nonwords, 6 of which were pre-trained on their phonology. The 16 individuals with Down syndrome aged 8–17 years were compared first to a group of 30 typically developing children aged 5–7 years matched for word reading and then to a subgroup of these children matched for decoding. There was a marginally significant effect for individuals with Down syndrome to benefit more from phonological pre-training than typically developing children matched for word reading but when compared to the decoding-matched subgroup, the two groups benefitted equally. We explain these findings in terms of partial decoding attempts being resolved by word level phonological knowledge and conclude that being familiar with the spoken form of a new word may help children when they attempt to read it. This may be particularly important for children with Down syndrome and other groups of children with weak decoding skills.
Gerontology has made considerable progress in the understanding of the mechanisms underlying the ageing process and age-related neurodegenerative disorders. However, ways to improve quality of life in the elderly remain to be elucidated. It is now clear that stress and the ageing process share a number of underlying mechanisms bound in a very close, if not indissociable, relationship. The ageing process is regulated by the factors underlying the ability to adjust to stress, whilst stress has an influence on the life span and the quality of ageing. In addition, the ability to cope with stress in adulthood predicts life expectancy and quality of life at senescence. The ageing process and stress also share several common mechanisms, particularly in relation to the energy factor. Stress consumes energy and ageing may be considered as a cost of the energy expended to deal with the stressors to which the body is exposed throughout its lifetime. This suggests that the ageing process is associated with and/or a consequence of a long-lasting activation of the major stress responsive systems. However, despite common features, the interaction between stress and the ageing process gives rise to some paradoxes. Stress can either diminish or exacerbate the ageing process just as the ageing process can worsen or counter the effects of stress. There has been little attempt to understand how ageing and stress might interact to promote “successful” or pathological ageing. A key factor in this respect is the individual's ability to adapt to stress. Viewed from this angle, the quality of life of aged subjects may be improved through therapy designed to improve the tolerance to stress.
The operating environment, manufacturing variability, and use can cause different degradation mechanisms to dominate capacity loss inside valve regulated lead-acid (VRLA) batteries. If an aging mechanism for each cell can be identified in real-time, cell usage can be adjusted by the battery management system to optimize the performance and service life of the energy storage system. In this paper, the cell voltage and pressure of new and dead VRLA batteries are monitored during testing to determine the cause of death of the cells. The new cells have fairly uniform performance with limited signs of degradation while the cells in the dead battery have widely ranging performance, especially at the end of discharge and charge. Based on the measurement data, it appears that one cell died from sulfation and another three died of dehydration. The battery capacity is mainly dictated by the sulfated cell. A desulfation charging control scheme with pressure feedback is designed to break up hard sulfate and recover capacity while minimizing water loss by using low current charging. The capacity of the cell is recovered by 41% with minimal water loss, demonstrating the effectiveness of the desulfation charge controller.
MgNiTi x , Mg1−x Ti x Ni and MgNi1−x Ti x (with x varying from 0 to 0.5) alloys have been prepared by high energy ball milling and tested as hydrogen storage electrodes. The initial discharge capacities of the Mg–Ni–Ti ternary alloys are inferior to the MgNi electrode capacity. However, an exception is observed with MgNi0.95Ti0.05, which has an initial discharge capacity of 575mAh/g compared to 522mAh/g for the MgNi electrode. The Mg–Ni-Ti ternary alloys show improved cycle life compared to Mg–Ni binary alloys with the same Mg/Ni atomic ratio. The best cycle life is observed with Mg0.5Ti0.5Ni electrode which retains 75% of initial capacity after 10 cycles in comparison to 39% for MgNi electrodes, in addition to improved high-rate dischargeability (HRD). According to the XPS analysis, the cycle life improvement of the Mg0.5Ti0.5Ni electrode can be related to the formation of TiO2 which limits Mg(OH)2 formation. The anodic polarization curve of Mg0.5Ti0.5Ni electrode shows that the current related to the active/passive transition is much less important and that the passive region is more extended than for the MgNi electrode but the corrosion of the electrode is still significant. This suggests that the cycle life improvement would be also associated with a decrease of the particle pulverization upon cycling.
To improve the tensile strength and ionic conductivity of composite polymer films for lithium-ion batteries, molecular sieves of MCM-41 modified with sulfated zirconia (SO4 2−/ZrO2, SZ), denoted as MCM-41/SZ, were doped into a poly(vinylidene fluoride) (PVdF) matrix to fabricate MCM-41/SZ composite polymer films, denoted as MCM-41/SZ films. Examination by transmission electron microscope (TEM) shows that modified molecular sieves have lower aggregation and a more porous structure. Tensile strength tests were carried out to investigate the mechanical performance of MCM-41/SZ films, and then the electrochemical performance of batteries with MCM-41/SZ films as separators was tested. The results show that the tensile strength (σ t) of MCM-41/SZ film was up to 7.8MPa; the ionic conductivity of MCM-41/SZ film was close to 10−3 Scm−1 at room temperature; and the coulombic efficiency of the assembled lithium-ion battery was 92% at the first cycle and reached as high as 99.99% after the 20th cycle. Meanwhile, the charge–discharge voltage plateau of the lithium-ion battery presented a stable state. Therefore, MCM-41/SZ films are a good choice as separators for lithium-ion batteries due to their high tensile strength and ionic conductivity.
The biosynthesis of high value-added compounds using metabolically engineered strains has received wide attention in recent years. Myo-inositol (inositol), an important compound in the pharmaceutics, cosmetics and food industries, is usually produced from phytate via a harsh set of chemical reactions. Recombinant Escherichia coli strains have been constructed by metabolic engineering strategies to produce inositol, but with a low yield. The proper distribution of carbon flux between cell growth and inositol production is a major challenge for constructing an efficient inositol-synthesis pathway in bacteria. Construction of metabolically engineered E. coli strains with high stoichiometric yield of inositol is desirable.
Boron-doped nanocrystalline diamond (B-NCD) films were grown by the hot filament chemical vapor deposition (HFCVD) technique on top of sharp electropolished tungsten substrates, in order to create amperometric microelectrodes (MEs) for detection of Zn2+(aq) and dissolved O2. The boron source was a B2O3 +ethanol mixture dragged by Argon gas through a bubbler. Different B2O3 concentrations were used to study the doping effect on the electrochemical behavior. The B-NCD MEs exhibited a working potential window of about 3.5V in 5mM NaCl, with low background current and good chemical inertness. The best electrochemical kinetics was achieved for the ME with highest boron doping content. The linear relationship between zinc concentration and zinc reduction current was found in a wide concentration interval from 10−5 M to 10−2 M of ZnCl2 in a 5mM NaCl background. Measurements with a Fe–Zn galvanic couple immersed in 5mM NaCl demonstrate potential applicability of the B-NCD ME for use in localized corrosion studies.
The performance of MXenes (Ti2CTx) combined with electrolytic manganese dioxide (EMD) in three different weight ratios (i.e. MXene:EMD = 20:80; 50:50; 80:20) were examined as anode material for Lithium-ion batteries (LIBs). A study of the structure, composition and morphology of the synthesized materials was conducted. The materials were further investigated for their electrochemical properties in a half-cell configuration using impedance spectroscopy measurements, cyclic voltammetry and galvanostatic charge-discharge cycling. Results showed that the combined MXene/EMD material has a greater cycling stability, capacity and rate capability as compared to the EMD. The best ratio was found to be MXene:EMD = 80:20. The capacity obtained for this material after 200 cycles is 460 mA h g−1 at a current density of 100 mA g−1. The Li-ion accessibility improved with cycling. This study provides a first insight into the viability of using one of the lightest known MXenes and EMD composite for improved LIB anodes. As EMD is a low cost and abundant material, it provides great opportunities for improved capabilities for lightweight applications at an affordable cost.
A majority of individuals with osteoarthritis (OA) are insufficiently physically active. Self-monitoring with wearable activity trackers (WAT) could promote physical activity (PA), and increased knowledge of PA patterns and adherence to using a WAT is needed. The aim of this study was to describe PA patterns and adherence to WAT-use during an intervention among participants of working age with hip and/or knee OA. The study further explores the correlation between self-reported joint function and PA.
Silicon and silicon containing compounds are attractive anode materials for lithium batteries because of their low electrochemical potential vs. lithium and high theoretical capacities. In this work the relationship between the electrochemical performance of silicon powders and their particle sizes was studied. It is found that the material with nano particle sizes gives the best performance. New silicon/carbon composite anode materials were synthesized and their structures and electrochemical performance were investigated. The results of these studies are reported in this paper.
Background Although electroconvulsive therapy (ECT) in major depression is effective, cognitive effects limit its use. Reducing the width of the electrical pulse and by using the right unilateral electrode placement may decrease adverse cognitive effects, while preserving efficacy. Methods In a double-masked study, we randomly assigned 90 depressed patients to right unilateral ECT at 6 times seizure threshold or bilateral ECT at 2.5 times seizure threshold, using either a traditional brief pulse (1.5 milliseconds) or an ultrabrief pulse (0.3 millisecond). Depressive symptoms and cognition were assessed before, during, and immediately, 2, and 6 months after therapy. Patients who responded were monitored for a 1-year period. Results The final remission rate for ultrabrief bilateral ECT was 35%, compared with 73% for ultrabrief unilateral ECT, 65% for standard pulse width bilateral ECT, and 59% for standard pulse width unilateral ECT (all P < .05 after covariate adjustment). The ultrabrief right unilateral group had less severe cognitive side effects than the other three groups in virtually all primary outcome measures assessed in the acute postictal period, and during and immediately after therapy. Both the ultrabrief stimulus and right unilateral electrode placement produced less short- and long-term retrograde amnesia. Patients rated their memory deficits as less severe after ultrabrief right unilateral ECT compared with each of the other three conditions (P < .001). Conclusions The use of an ultrabrief stimulus markedly reduces adverse cognitive effects, and when coupled with markedly suprathreshold right unilateral ECT, also preserves efficacy. (ClinicalTrials.gov number, NCT00487500.)
Much of current research in electrochemical energy storage is devoted to new electrode chemistries and reaction mechanisms that promise substantial increases in energy density. Unfortunately, most high capacity electrodes exhibit an unacceptably large hysteresis in their voltage profile. Using a first-principles multi-scale approach to examine particle level dynamics, we identify intrinsic thermodynamic and kinetic properties that are responsible for the large hysteresis exhibited by many high capacity electrodes. Our analysis shows that the hysteresis in the voltage profile of high capacity electrodes that rely on displacement reactions arises from a difference in reaction paths between charge and discharge. We demonstrate that different reaction paths are followed (i) when there is a large mismatch in ionic mobilities between the electrochemically active species (e.g. Li) and displaced ionic species and (ii) when there is a lack of a thermodynamic driving force to redistribute displaced ions upon charging of the electrode. These insights motivate the formulation of design metrics for displacement reactions in terms of fundamental properties determined by the chemistry and crystallography of the electrode material, properties that are now readily accessible with first-principles computation.