batterydata/paper-abstracts huggingface dataset:
In this paper, the electrochemical reactions of sulfur cathode during discharge–charge process were investigated by EIS technique combining with XRD, SEM and EDS methods. The discharge process of the sulfur cathode could be divided into two discharge regions. These are the first discharge region (2.5–2.05V) where the reduction of elemental sulfur to form soluble polysulfides and further reduction of the soluble polysulfides occurs, and the second discharge region (2.05–1.5V) where the soluble polysulfides are reduced to form a Li2S solid film covered over the carbon matrix. It was found that the EIS can distinguish the individual contributions of charge transfer resistances, ion diffusion impedance and properties originating from Li2S film in the frequency domain of 100kHz to 100mHz. During the upper voltage plateau, the impedance of interfacial charge transfer dominates the reduction reaction, while during the lower voltage plateau, the mass transport in the cathode is a control step. It was also proved that the solid Li2S appeared at the beginning of the lower voltage plateau region and became denser during the following discharge process.
Experimental evidence has shown that composites comprised Si and Sn nanoparticles embedded inside a matrix are the most promising next generation anodes for Li-ion batteries. This is due to the ability of the matrix material to constrain/buffer the up to 300% volume expansion that Sn and Si undergo upon the formation of lithium rich alloys. Damage still occurs at the nanoparticle/matrix interface, and hence further materials design is required in order to commercialize such anodes. Initial theoretical works have predicted that low volume fractions and high aspect ratios of the nanoparticles result in a greater mechanical stability and hence better capacity retention. The most important design parameters, however, such as particle size and spacing have not been considered theoretically. In the present study, therefore, a gradient enhanced damage model will be employed to predict that damage during Li-insertion, is negligible when the particle size is 20nm, and the interparticle half-spacing greater then 1.5 times the particle diameter. Furthermore, from the matrix materials considered herein graphene is predicted to be the most promising matrix, which is consistent with recent experimental data.
Genotoxicity is one of the important endpoints for risk assessment of environmental chemicals. Many short-term assays to evaluate genotoxicity have been developed and some of them are being used routinely. Although these assays can generally be completed within a short period, their throughput is not sufficient to assess the huge number of chemicals, which exist in our living environment without information on their safety. We have evaluated three commercially available in silico systems, i.e., DEREK, MultiCASE, and ADMEWorks, to assess chemical genotoxicity. We applied these systems to the 703 chemicals that had been evaluated by the Salmonella/microsome assay from CGX database published by Kirkland et al. [1]. We also applied these systems to the 206 existing chemicals in Japan that were recently evaluated using the Salmonella/microsome assay under GLP compliance (ECJ database). Sensitivity (the proportion of the positive in Salmonella/microsome assay correctly identified by the in silico system), specificity (the proportion of the negative in Salmonella/microsome assay correctly identified) and concordance (the proportion of correct identifications of the positive and the negative in Salmonella/microsome assay) were increased when we combined the three in silico systems to make a final decision in mutagenicity, and accordingly we concluded that in silico evaluation could be optimized by combining the evaluations from different systems. We also investigated whether there was any correlation between the Salmonella/microsome assay result and the molecular weight of the chemicals: high molecular weight (>3000) chemicals tended to give negative results. We propose a decision tree to assess chemical genotoxicity using a combination of the three in silico systems after pre-selection according to their molecular weight.
Iron oxide has been considered as one of the most promising anode materials due to its high theoretical capacity, low cost and environmental friendliness. However, few simple and effective method is explored for preparing iron oxides with high electrochemical performance via alleviating the volume change and agglomeration of active particles. In this work, FeO x /carbon/graphene composites are fabricated by a facile solution combustion synthesis within several minutes in one step. Characterization demonstrates that FeO x nanoparticles are well-dispersed in the graphene matrix. The presence of graphene effectively alleviates the agglomeration of FeO x nanoparticles, and accommodates the volume changes during the cycling process, thereby resulting in the excellent electrochemical performance. FeO x /carbon/graphene (31.4wt.% graphene) delivers a higher discharge capacity of 824mAhg−1 after 100 cycles at 0.4Ag−1, in comparison to the value of 301mAhg−1 for the composite without graphene. This easily prepared FeO x /carbon/graphene composite with excellent electrochemical performance can be considered as one promising anode material used for lithium-ion batteries.
A widely used oxyanion corrosion inhibitor (Li2CrO4) was used as electrolyte additive (3.5 wt% NaCl solution was used as electrolyte solution) for Mg–air battery. The potentiodynamic polarization tests showed that the presence of 0.1 wt% Li2CrO4 in the NaCl electrolyte reduced enormously the corrosion current density of the tested AZ31 Mg alloys. According to the intermittent discharge tests, the use of 0.1 wt% Li2CrO4 as electrolyte additive increased the anode efficiency of the Mg–air battery by 28.4%. The addition of 0.1 wt% Li2CrO4 reduced the anode self-corrosion rate of the battery in the intermittent stage effectively. The product film after discharge was observed by scanning electron microscope, and the Mg–air battery containing 0.1 wt% Li2CrO4 has a loose product film, which is beneficial to its discharge performance. So using Li2CrO4 as electrolyte additive could improve the intermittent discharge performance of Mg–air battery. And the use of oxyanion corrosion inhibitor as electrolyte additive may be an excellent way to improve the intermittent discharge performance of Mg–air battery.
Experimental work was performed with the aim of evaluating the Ce4+/Ce3+ redox couple in sulfuric acid electrolyte for use in redox flow battery (RFB) technology. The solubility of cerium sulfates in 0.1–4.0M sulfuric acid at 20–60°C was studied. A synergistic effect of both sulfuric acid concentration and temperature on the solubility of cerous sulfate was observed. The solubility of cerous sulfate significantly decreased with rising concentration of sulfuric acid and rising temperature, while the solubility of ceric sulfate goes through a significant maximum at 40°C. Redox potentials and the kinetics of the cerous/ceric redox reaction were also studied under the same temperature–concentration conditions. The redox potentials were measured using the combined redox electrode (Pt–Ag/AgCl) in equimolar Ce4+/Ce3+ solutions (i.e.[Ce3+]=[Ce4+]) in sulfuric acid electrolyte. The Ce3+/Ce4+ redox potentials significantly decrease (i.e. shift to more negative values) with rising sulfuric acid concentration; a small maximum is observed at 40°C. Cyclic voltammetric experiments confirmed slow electrochemical kinetics of the Ce3+/Ce4+ redox reaction on carbon glassy electrodes (CGEs) in sulfuric acid solutions. The observed dependencies of solubilities, the redox potentials and the kinetics of Ce3+/Ce4+ redox reaction on sulfuric acid concentration are thought to be the result of inequivalent complexation of the two redox species by sulfate anions: the ceric ion is much more strongly bound to sulfate than is the cerous ion. The best temperature–concentration conditions for the RFB electrolytes appear to be 40°C and 1M sulfuric acid, where the relatively good solubility of both cerium species, the maximum of redox potentials, and the more or less satisfying stability of CGE s were found. Even so, the relatively low solubility of cerium salts in sulfuric acid media and slow redox kinetics of the Ce3+/Ce4+ redox reaction at carbon indicate that the Ce3+/Ce4+ may not be well suited for use in RFB technology.
The ability to generate complex hierarchical structures is a crucial component of human cognition which can be expressed in the musical domain in the form of hierarchical melodic relations. The neural underpinnings of this ability have been investigated by comparing the perception of well-formed melodies with unexpected sequences of tones. However, these contrasts do not target specifically the representation of rules generating hierarchical structure. Here, we present a novel paradigm in which identical melodic sequences are generated in four steps, according to three different rules: The Recursive rule, generating new hierarchical levels at each step; The Iterative rule, adding tones within a fixed hierarchical level without generating new levels; and a control rule that simply repeats the third step. Using fMRI, we compared brain activity across these rules when participants are imagining the fourth step after listening to the third (generation phase), and when participants listened to a fourth step (test sound phase), either well-formed or a violation. We found that, in comparison with Repetition and Iteration, imagining the fourth step using the Recursive rule activated the superior temporal gyrus (STG). During the test sound phase, we found fronto-temporo-parietal activity and hippocampal de-activation when processing violations, but no differences between rules. STG activation during the generation phase suggests that generating new hierarchical levels from previous steps might rely on retrieving appropriate melodic hierarchy schemas. Previous findings highlighting the role of hippocampus and inferior frontal gyrus may reflect processing of unexpected melodic sequences, rather than hierarchy generation per se.
While the textile based stretchable supercapacitors have been demonstrated as efficient charge storage devices, challenges in developing self powered wearable devices still exist. The present work describes a screen printed flexible and stretchable supercapacitor that can act as an energy buffering element for powering wearable fitness monitoring devices. The supercapacitor possesses interdigitated shaped intrinsically stretchable electrodes with free-standing serpentine interconnects. The symmetric supercapacitor relies on carbon nanotube and poly(aniline) as active materials and polyurethane as a stretch enduring binder. Such in-plane supercapacitors are realized by initially printing on a paper substrate, pre-coated with a water soluble layer, and then transferred onto a pre-strained elastomeric substrate. The supercapacitor showed excellent mechanical resiliency even though subjected to intense mechanical deformations. The electrode possessed highest areal capacitance of 167 mF/cm2 at a current density of 0.4 mA/cm2 and showed appreciable areal energy and power density of 14.9 μWh/cm2 and 0.29 mW/cm2, respectively. The supercapacitor showed conformal integration with the stretchable sweat band and which (3 devices, in series) can independently power a red light emitting diode. In combination with a flexible solar cell and a custom-made low power booster, the supercapacitor can continuously powers the wearable pulse rate sensor even in the presence of poor sunlight intensity.
The effects of increasing levels of metals (10 and 20 mg of Cr kg-1 and 25 and 50 mg of Cd, Pb, and Ni kg-1 soil) and arbuscular mycorrhizal (AM) fungi Glomus intraradices on the yield, chemical composition of volatile oil, and metal accumulation in sweet basil (Ocimum basilicum L.) were investigated in a pot experiment. The shoot yield, content of essential oil, and root yield of sweet basil were increased by the application of low dose of Cd, Pb, and Ni as compared to control. The application of high level of metals had deleterious effect on the yield. In soil with low dose of metal applied, AM fungi inoculation significantly enhanced the metal concentration in shoots and had adverse effect on the yield, whereas in soil with high dose of metal applied, AM fungal inoculation reduced the metal concentration in shoot and had beneficial effect on the yield. The content of linalool in basil oil was decreased and that of methyl chavicol was increased by the application of Cr, Cd, and Pb in soil as compared to control. Similarly, the level of linalool and methyl chavicol was decreased and that of methyl eugenol was increased by the application of Ni as compared to control. However, AM fungal inoculation led to maintain the content of linalool, methyl chavicol, and methyl eugenol in volatile oil, which were either increased or decreased by the application of metals. We conclude that the AM–sweet basil symbiosis could be used as a novel approach to enhance the yield and maintain the quality of volatile oil of sweet basil under metal-contaminated soils.
Evolution of the chemical bonding nature and electrochemical activity of indium selenide upon the composite formation with carbon species is systematically investigated. Nanocomposites of In4Se2.85@graphene and In4Se2.85@carbon-black are synthesized via a solid state reaction between In and Se elements, and the following high energy mechanical milling of In4Se2.85 with graphene and carbon-black, respectively. The high energy mechanical milling (HEMM) of In4Se2.85 with carbon species gives rise to a decrease of particle size with a significant depression of the crystallinity of In4Se2.85 phase. In contrast to the composite formation with carbon-black, that with graphene induces a notable decrease of (InSe) bond covalency, underscoring significant chemical interaction between graphene and In4Se2.85. Both the nanocomposites of In4Se2.85@graphene and In4Se2.85@carbon-black show much better anode performance for lithium ion batteries with larger discharge capacity and better cyclability than does the pristine In4Se2.85 material, indicating the beneficial effect of composite formation on the electrochemical activity of indium selenide. Between the present nanocomposites, the electrode performance of the In4Se2.85@graphene nanocomposite is superior to that of the In4Se2.85@carbon-black nanocomposite, which is attributable to the weakening of (InSe) bonds upon the composite formation with graphene as well as to the better mixing between In4Se2.85 and graphene. The present study clearly demonstrates that the composite formation with graphene has strong influence on the chemical bonds and electrode activity of indium selenide and the HEMM process with graphene nanosheet is fairly useful in exploring excellent electrode materials of metal chalcogenide–carbon nanocomposite for lithium ion batteries.
Olivine LiFePO4 is synthesized by a carbothermal reduction method (CTR) using industrial raw materials with polyethylene glycol (PEG) as a reductive agent and carbon source. A required amount of acetone is added to the starting materials for the ball milling process and the precursor is sintered at 973K for 8h to form crystalline phase LiFePO4. The structure and morphology of the LiFePO4/C composite samples have been characterized by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, energy-dispersive spectroscopy, differential scanning calorimetry and magnetic susceptibility. Electrochemical measurements show that the LiFePO4/C composite cathode delivers an initial discharge capacity of 150mAhg−1 at a 0.2C-rate between 4.0 and 2.8V, and almost no capacity loss is observed for up to 50 cycles. Remarkably, the cell can sustain a 30C-rate between 4.6 and 2.0V, and this rate capability is equivalent to charge or discharge in 2min. The simple technique, low-cost starting materials, and excellent electrochemical performance make this process easier to commercialize than other synthesized methods.
We consider the setting of a device that obtains its energy from a battery and some regenerative source such as a solar cell. We consider the speed scaling problem of scheduling a collection of tasks with release times, deadlines, and sizes, so as to minimize the energy recharge rate of the regenerative source. This is the first theoretical investigation of speed scaling for devices with a regenerative energy source. We show that the problem can be expressed as a polynomial sized convex program. We show that, using the KKT conditions, one can obtain an efficient algorithm to verify the optimality of a schedule. We show that the energy optimal YDS schedule is 2-approximate with respect to the recharge rate. We show that the online algorithm BKP is O ( 1 ) -competitive with respect to recharge rate.
Ethylene glycol bis (propionitrile) ether (EGBE) is used as an electrolyte additive to improve the cycling stability and rate capability of Li/Li1.2Mn0.54Ni0.13Co0.13O2 cells at high operating voltage (4.8 V). After 150 cycles, cells with 1.0 wt% of EGBE containing electrolyte have remarkable cycling performance, 89.0% capacity retention; while the cells with baseline electrolyte only remain 67.4% capacity retention. Linear sweep voltammetry (LSV) and computation results demonstrate that EGBE preferably oxidizes on the cathode surface compared to the LiPF6/carbonate electrolyte. In order to further understand the effects of EGBE on Li1.2Mn0.54Ni0.13Co0.13O2 cathode upon cycling at high voltage, electrochemical behaviors and ex-situ surface analysis of Li1.2Mn0.54Ni0.13Co0.13O2 are investigated via electrochemical impedance spectroscopy (EIS), scanning electron spectroscopy (SEM), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and inductive coupled plasma spectroscopy (ICP-MS). The improved cycling performance can be attributed to more stable and robust surface layer yield via incorporation of EGBE, which mitigates the oxidation of electrolyte on the cathode electrode, and also inhibits the dissolution of bulk transition metal ions as well upon cycling at high voltage.
One of the most prominent symptoms of schizophrenia is thought disorder, which manifests itself in language production difficulties. In patients with thought disorders the associations are loosened and sentence production is impaired. The determining behavioral and neural mechanisms of sentence production are still an important subject of recent research and have not yet been fully understood. The aim of the current study was to examine the influence of associative relations and distractor modalities on sentence production in healthy participants and participants with schizophrenia. Therefore, reaction times and neural activation of 12 healthy subjects and 13 subjects with schizophrenia were compared in an adapted picture word interference paradigm (PWI). No significant group differences were found, neither on the behavioral nor on the neural level. On the behavioral level, for the entire group incremental sentence processing was found, i.e. processing of the second noun only starts after the first noun was processed. At the neural level, activation was discovered in the bilateral caudate nuclei and the cerebellum. Those activations could be related to response enhancement and suppression as well as to the modulation of cognitive processes.
The research, development and application of high energy density lithium ion batteries are strictly restricted by several challenges, particularly the severe capacity degradation of the batteries at high voltage and elevated temperature. In this work, beneficial surface films are simultaneously formed on both electrodes of a 4.5 V graphite│LiNi0.5Mn0.3Co0.2O2 pouch cell via reduction and oxidation polymerizations of a novel multifunctional additive Tripropargyl Phosphate (TPP). The results demonstrate that the addition of 1.0 wt% TPP into the pouch cell not only improves its initial coulombic efficiency by 4.4%, but also remarkably enhances its cycling stability at both 25 °C and 55 °C. The enhanced cycling stability at high temperature can be attributed to the capture of acidic corrosive species in the electrolyte and the construction of robust protective films on the surface of the electrodes. These two effects significantly mitigate the decomposition of Ethyl Methyl Carbonate (EMC), reduce the dissolution of transition metal from cathode, and eliminate the formation of cracks inside the LiNi0.5Mn0.3Co0.2O2 and graphite particles.
Global positioning systems (GPS) and mobile phone networks make it possible to track individual users with an increasing accuracy. It is natural to ask whether this information can be used to maintain social networks. In such a network each user wishes to be informed whenever one of a list of other users, called the user’s friends, appears in the user’s vicinity. In contrast to more traditional positioning based algorithms, the computation here depends not only on the user’s own position on a static map, but also on the dynamic position of the user’s friends. Hence it requires both communication and computation resources. The computation can be carried out either between the individual users in a peer-to-peer fashion or by centralized servers where computation and data can be collected at one central location. In the peer-to-peer model, a novel algorithm for minimizing the number of location update messages between pairs of friends is presented. We also present an efficient algorithm for the centralized model, based on region hierarchy and quadtrees. The paper provides an analysis of the two algorithms, compares them with a naive approach, and evaluates them on user motions generated by the IBM City Simulator system.
The piezoelectric transformers reach densities of power more significant than their magnetic counterparts. However, one of the principal factors limiting the density of power is the acceptable maximum deformation by material constituting the transformer. The heating of the piezoelectric transformers is mainly of mechanical origin. This heating generates a degradation of the characteristics which in its turn generates an additional heating being able to lead to a phenomenon of thermal avalanche. In this work, two nonlinear methods [synchronized switch harvesting on inductor (SSHI) and SSHI-max] have been explored to improve the performance of the Rosen transformer basing on the tension generated by the secondary so as to increase the capacity of mechanic-electric conversion. The simulation results show that SSHI and SSHI-max techniques significantly increase the capacity of mechanic-electric conversion of inserts stuck on a vibrating structure and consequently, the power recovered in electric form. The comparative results of voltage gain, efficiency and the transmitted power of the transformer, before and after SSHI-max and SSHI control are given. These ones indicated that the two nonlinear techniques are promising as applications to improve the performances of the piezo-transformers.