batterydata/paper-abstracts huggingface dataset:
Deficits in executive functions (EF) have been found in school-age children and adolescents with externalizing behavior disorders. Present meta-analysis was carried out to determine whether these EF impairments can also be found in preschool children with externalizing behavior problems. Twenty-two studies were included with a total of 4021 children. Four separate meta-analyses were conducted, concerning overall EF, working memory, inhibition and cognitive flexibility. A medium correlation effect size was obtained for overall EF (ESzr = 0.22) and for inhibition (0.24), whereas a small effect size was found for working memory (0.17) and for cognitive flexibility (0.13). Moderator analyses revealed a stronger effect for older preschoolers compared to younger preschoolers, and for children from referred samples compared to community samples. These results show that EF, especially inhibition, is related to externalizing behavior problems already in preschool years.
This review highlights the recent research advances in active nanostructured anode materials for the next generation of Li-ion batteries (LIBs). In fact, in order to address both energy and power demands of secondary LIBs for future energy storage applications, it is required the development of innovative kinds of electrodes. Nanostructured materials based on carbon, metal/semiconductor, metal oxides and metal phosphides/nitrides/sulfides show a variety of admirable properties for LIBs applications such as high surface area, low diffusion distance, high electrical and ionic conductivity. Therefore, nanosized active materials are extremely promising for bridging the gap towards the realization of the next generation of LIBs with high reversible capacities, increased power capability, long cycling stability and free from safety concerns. In this review, anode materials are classified, depending on their electrochemical reaction with lithium, into three groups: intercalation/de-intercalation, alloy/de-alloy and conversion materials. Furthermore, the effect of nanoscale size and morphology on the electrochemical performance is presented. Synthesis of the nanostructures, lithium battery performance and electrode reaction mechanisms are also discussed. To conclude, the main aim of this review is to provide an organic outline of the wide range of recent research progresses and perspectives on nanosized active anode materials for future LIBs.
Purpose To inform ophthalmologists of the current status of visual training. Design Personal perspective. Method A perspective and analysis of current practices that include a review of the literature and personal experiences of the author. Results Visual training of some sort has been used for centuries. In the first half of the twentieth century, in cooperation with ophthalmologists, orthoptists introduced a wide variety of training techniques that were designed primarily to improve binocular function. In the second half of the twentieth century, visual training activities were taken up by optometrists and paramedical personnel to treat conditions that ranged from uncomfortable vision to poor reading or academic performance. Other visual training has been aimed at the elimination of a wide variety of systemic symptoms and for the specific improvement of sight and even for the improvement of athletic performance. At present, ophthalmologists and orthoptists use visual training to a very limited degree. Most visual training is now done by optometrists and others who say it works. Based on an assessment of claims and a study of published data, the consensus of ophthalmologists regarding visual training is that, except for near point of convergence exercises, visual training lacks documented evidence of effectiveness. Conclusion Although visual training has been used for several centuries, it plays a minor and actually decreasing role in eye therapy used by the ophthalmologist. At the beginning of the twenty-first century, most visual training is carried out by non-ophthalmologists and is neither practiced nor endorsed in its broadest sense by ophthalmology.
Proton exchange membrane fuel cells (PEMFCs) have recently passed the test or demonstration phase and have partially reached the commercialization stage due to the impressive worldwide research effort. Despite the currently promising achievements and the plausible prospects of PEMFCs, there are many challenges remaining that need to be overcome before PEMFCs can successfully and economically substitute for the various traditional energy systems. With the many promising research efforts in overcoming these challenges, the most important tools for the commercialization of PEMFCs will be the technical data and information from a real PEMFC application test. For these reasons, this paper introduces and discusses the remaining challenges and some of the latest research on the application test of PEMFC to real systems such as transportation, residential power generation and portable computers. In addition, this paper describes and summarizes the relative prospects and the competitive force of PEMFCs in these fields. These prospects primarily depend on stable and economical high-purity hydrogen supplies, the scale of application, the existence of more efficient competitive power sources and the social viewpoints such as the health and environment benefits as well as infrastructural aspects associated with traditional power supply and demand. The review shows that PEMFC have the most promising applications to buses, recreation vehicles, and lightweight vehicles. Without doubt, the technology for a stable supply of high-purity hydrogen along with the corresponding infrastructure is essential for the success of PEMFC in various application fields.
The electrochemical oxidation of BH4 − in 2M NaOH on Pt and Au (i.e. catalytic and non-catalytic electrodes, respectively, for BH4 − hydrolysis accompanied by H2 evolution) has been studied by cyclic voltammetry, chrono-techniques (i.e., potentiometry, amperometry, coulometry) and electrochemical impedance spectroscopy. In the case of Pt the cyclic voltammetry behaviour of BH4 − is influenced by both, the catalytic hydrolysis of BH4 − yielding H2 (followed by electrooxidation of the latter at peak potentials between −0.7 and −0.9V versus Ag/AgCl, KClstd) and direct oxidation of BH4 − at more positive potentials, i.e., between −0.15 and −0.05V. Thiourea (TU, 1.5×10−3 M) was an effective inhibitor of the catalytic hydrolysis associated with BH4 − electrooxidation on Pt. Therefore, in the presence of TU, only the direct oxidation of BH4 − has been detected, with peak potentials between −0.2 and 0V. It is proposed that TU could improve the BH4 − utilization efficiency and the coulombic efficiency of direct borohydride fuel cells using catalytic anodes. The electrooxidation of BH4 − on Pt/TU is an overall four-electron process, instead of the maximum eight electrons reported for Au, and it is affected by adsorbed species such as BH4 − (fractional surface coverage ∼0.3), TU and possibly reaction intermediates.
Blood–brain barrier (BBB) disruption, inflammation, and cell death are the pathogenic mechanisms of cerebral ischemia/reperfusion (I/R) injury. Nicorandil protects ischemic injury via some of these mechanisms. The aim of this study was to investigate the therapeutic effects of this drug on the brain ischemia after transient middle cerebral artery occlusion (MCAO) and clarify the NF-κB and Nrf2-dependent mechanisms modulated by this drug. Sixty-six rats were randomized into sham, MCAO and MCAO + nicorandil groups with oral gavage for 3 days. Cerebral I/R injury were induced by a transient MCAO for 1 h and neurobehavioral scores were performed for 3 days. In addition to measurement of BBB disruption and brain water content, the total and infarct volume, density, and total number of neurons, non-neurons and dead neurons in the right cortex were estimated by unbiased stereological methods. RT-PCR was performed to analyze the expression levels of NF-κB and Nrf2. Although nicorandil treatment in the sub-acute brain ischemia did not have a prominent effect on neurobehavioral function and number of neurons, non-neurons and dead neurons probably through up-regulation of NF-κB, it, however, improved ischemia-induced BBB disruption and brain edema and showed a significant reduction in the infarction volume probably through up-regulation of Nrf2.
Converting ‘trash’ waste residua to active functional materials ‘treasure’ with high added value is being regarded as a promising way to achieve the sustainable energy demands. Carbonaceous materials cannot insert sodium except when graphite co-intercalates solvents such as diglyme. Here, we show that petroleum coke and shale coke annealed at different temperatures can also insert sodium by reversible intercalation phenomena in a diglyme-based electrolyte. The structural and morphological studies will reveal significant differences justifying their distinct electrochemical behavior. Galvanostatic tests exhibit a flat plateau at about 0.7 V ascribable to the reversible reaction. At the end of the discharge, a Stage-I ternary intercalation compound is detected. Two diglyme molecules are co-intercalated per alkali ion, as evidenced by 1-D Patterson diagrams, FTIR and TGA analyses. The full sodium-ion cell made with P-2500/NaPF6(diglyme)/Na3V2(PO4)3 delivered an initial reversible capacity of 75 mA h g−1 at C rate and an average potential of 2.7 V. Thus, the full cell provides an energy density of 202 W h kg−1. This sodium-ion system can be considered a promising power source that encourages the potential use of low-cost energy storage systems.
In this paper, oscillatory electrodissolution of Al in perchloric acid solutions has been investigated. The Al/HClO4 system is a new electrochemical oscillator and particularly, current oscillations occur over a large range of HClO4 concentration and over a wide scale of applied potential. The effects of the applied potential and the HClO4 concentration on the current oscillations have been studied. The results are discussed in terms of the formation and dissolution of the surface oxide film. During the anodic dissolution of the Al electrode in HClO4 solutions, perchlorate ions are reduced to chloride ions, by which, pitting corrosion is induced. The surface morphologies of Al electrodes observed using an environmental scanning electron micrograph show that it is pitting corrosion that induces the current oscillations.
Selenium encapsulated into 3D interconnected hierarchical porous carbon aerogels (HPCA) as a carbon/selenium composite material is prepared for lithium–selenium batteries. Scanning electron microscope (SEM) and transmission electron microscope (TEM) observations show the hierarchical porous structures of the carbon aerogels and the homogeneous distribution of selenium in the composite. The performance of the HPCA/Se cathode is evaluated in lithium–selenium batteries using cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy. It is found that the HPCA/Se cathode shows high rate performance, coulombic efficiency and cycling stability. The HPCA/Se cathode has a highest coulombic efficiency which is kept above 98% after 50th cycle in ionic liquid N-methyl-(n-butyl) pyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR14TFSI) modified electrolyte and retains 309 mAh g−1 after 100 discharge/charge cycles at a high rate of 0.5 C (337.5 mAh g−1) in LiNO3 modified electrolyte, respectively. Even at the current density of 5 C (3375 mAh g−1), it can still maintain at a reversible capacity of 301 mAh g−1. The excellent electrochemical properties benefit from the high electron conductivity and 3D interconnected hierarchical porous structures of the carbon aerogels, which contribute to disperse selenium and absorb polyselenides, and suppress the formation of residual Li2Se layer.
Carbon coating is an effect way to improve the electronic conductivity of polyanion materials for lithium ion batteries. A citric acid assisted sol–gel method is employed in this study to prepare Li2MnSiO4/C composite, where carbon is in situ coated on Li2MnSiO4 during the synthetic process. The effect of in situ carbon coating on the structural, morphological and electrochemical characteristics is studied in detail. The particle size decreases whereas the amount of impurities increases with increasing amount of carbon. The Li2MnSiO4/C sample with 2.1wt% carbon shows the best electrochemical performance, and the particle of it is uniformly coated by a thin layer of carbon. The carbon coating is incomplete if the amount of carbon is lower than 2.1wt%. However, uneven thick layer and/or agglomerates of carbon are formed if the amount of carbon is higher than 2.1wt%. Li+ transfer on the surface of particles will be hindered if the carbon layer is too thick. Although the smaller particles of the samples with 8.5wt% and 10.5wt% carbon have a positive effect on their electrochemical performance, the combined negative effect of higher amount of impurities and thicker carbon layer with carbon agglomerates finally lead to poorer electrochemical performance.
In evolutionary psychology, it is customary to measure life-history via psychometric inventories such as the Arizona Life History Battery (ALHB). The validity of this approach has been questioned: it is argued that these measures are not congruent with biological life history events, such as the number of children, age at first birth, or pubertal timing. However, empirical data to test this critique are lacking. We therefore administered the ALHB to a convenience sample of young adults in Serbia (N = 447). We also collected information on psychosocial-biodemographic life history parameters closely related to biological life history traits: pubertal timing, onset of sexual behavior, short- and long-term mating, number of children, timing of reproduction, parenthood values, and environmental harshness. We found that correlations between these two sets of measures were rare, unsystematic, and mostly low in magnitude. Stable patterns of relations emerged only between the indicators of environmental conditions from both sets of measures. Furthermore, some ALHB indicators were found to be positively related with early fertility, which is incongruent with the conceptual foundation of ALHB. Finally, network analysis and factor analysis within each set of measures revealed different structures and that the hypothesis of unidimensionality, on which the ALHB was founded, cannot be applied to psychosocial-biodemographic life history indicators. Our results support the critique of ALHB as a set of measures lacking validity to capture biodemographic life-history parameters. ALHB measures are indeed relevant for understanding life-history variation, but they cannot be used as a substitute for specific life history characteristics. Our findings are a warning to researchers to use direct measures of biological events in order to measure life-history dynamics.
A new and novel electrically conducting ‘polymeric–inorganic’ composite cation-exchange material; polyaniline Sn(IV) tungstoarsenate was prepared by incorporating polyaniline into inorganic ion-exchanger material. It possessed improved ion-exchange capacity, high chemical and thermal stabilities, reproducibility and selectivity for some specific metal ions. Kinetic study of exchange for some divalent metal ions of alkaline earths and transition metals was carried out under the conditions favoring a particle diffusion-controlled ion-exchange phenomenon and some physical parameters such as self diffusion coefficient D 0, energy of activation E a and entropy of activation ΔS* were determined. The temperature dependence of electrical conductivity of this composite material with increasing temperatures was measured by using 4-in-line-probe DC electrical conductivity measuring-technique. The conductivity values lie in the semiconductor region, i.e. in the range of 10−3 S cm−1 that follow the Arrhenius equation. The energy of activation of electrical conduction for the composite was also calculated.
The development of safe and long-term stable solid polymer electrolytes is a major challenge for all solid-state batteries because good interfacial stability toward electrodes is the main concern. In this paper, a triblock copolymer polystyrene-poly(ethylene glycol)-polystyrene (PS-PEG-PS) is synthesized and investigated as solid polymer electrolyte. This polymer electrolyte exhibits a high ionic conductivity of 1.1 × 10−3 S cm −1 at 70 °C, transference number of 0.17, high degree flexibility, good mechanical strength and thermal stability. The interface stability of the solid-polymer electrolyte is investigated in Li metal cell and the comprehensive electrochemical properties are studied in cells with either LiFePO4 or LiNi0.5Co0.3Mn0.2O2 cathode materials. Good rate capability and excellent cyclability of the solid polymer electrolyte is demonstrated, with an electrochemical stability window extending above 4.5 V vs. Li+/Li. Furthermore, constant voltage impedance measurements give evidence of the better interface stability and rate capability of LiNi0.5Co0.3Mn0.2O2//Li battery. Meanwhile, molecular orbital energy levels calculated by density functional theory are consistent with experiments.
One of the key battery performances which can be described as the resistance characteristic is the cell voltage response with dynamic currents, and it requires synchronous cell voltages and current. But due to inevitable network latency in modular battery management system (BMS) with controller area network (CAN), cell voltages and current are usually asynchronous. We firstly analyze the sampling and the storage process of battery signals to study the asynchronous mechanism in BMS. We develop an on-line synchronization method using a “global clock” from the master controller to decrease the time delay as much as possible. And we further propose a model based sync method based on the frequency division equivalent circuit model (FDECM) for the battery pack. The low frequency cell difference model is used to identify cell “resistances difference”, and then the optimal time compensation for cell voltages is obtained when the minimum mean absolute derivative (MAD) value of identified resistance differences is reached according to the low frequency characteristic of cell “resistances difference”. The proposed methods are verified by simulation and experiment. The current and cell voltages in the data logger of BMS can be synchronized when the optimal compensation time is applied respectively for each cell. The data after synchronization can meet the requirements of further data analysis and processing, which is of great significance to enhance and improve the control strategy of BMS.
We report on a carbon/carbon hybrid electrochemical capacitor (hybrid EC) based on an aqueous redox-active electrolyte, which operates efficiently down to −40 °C. The electrolyte comprises choline iodide (ChI; 0.5 mol kg−1) as redox active component and choline nitrate (ChNO3; 5 mol kg−1) as supporting salt which enables the liquid state to be extended down to −42 °C, as proved by differential scanning calorimetry. Interestingly, the hybrid EC displays a high discharge capacitance of 81 F g−1 (at 0.1 A g−1; per total mass of electrodes), which is twice higher than its symmetric counterpart utilizing only an aqueous solution of ChNO3 (41 F g−1). The doubling of cell capacitance results from hybridization of the positive battery-type electrode (harnessing redox reactions of polyiodides trapped in carbon porosity) with the negative electrical double-layer (EDL) capacitive electrode. Even at −40 °C, the hybrid EC retains a high capacitance of 50 F g−1 and shows negligible ohmic drop. As its energy and power performance is in the same range as for EDL capacitors using tetraethylammonium tetrafluoroborate in acetonitrile, this new hybrid EC is a highly cost-effective and green alternative to these traditional systems.
A hydrogen fuelled, 30W proton exchange membrane fuel-cell (PEMFC) system is presented that is able to operate at an ambient temperature between −20 and 40°C. The system, which comprises the fuel-cell stack, pumps, humidifier, valves and blowers is fully characterized in a climatic chamber under various ambient temperatures. Successful cold start-up and stable operation at −20°C are reported as well as the system behaviour during long-term at 40°C. A simple thermal model of the stack is developed and validated, and accounts for heat losses by radiation and convection. Condensation of steam is addressed as well as reaction gas depletion. The stack is regarded as a uniform heat source. The electrochemical reaction is not resolved. General design rules for the cold start-up of a portable fuel-cell stack are deduced by the thermal model and are taken into consideration for the design. The model is used for a comparison between active-assisted cold start-up procedures with a passive cold start-up from temperatures below 0°C. It is found that a passive cold start-up may not be the most efficient strategy. Additionally, the influence of different stack concepts on the start-up behaviour is analysed by the thermal model. Three power classes of PEMFC stacks are compared: a Ballard Mk902 module for automotive applications with 85kW, the forerunner stack Ballard Mk5 (5kW) for medium power applications, and the developed OutdoorFC stack (30W), for portable applications.
Cu6Sn5 alloy nanoparticles dispersed in a TiC and C conductive matrix have been developed via high energy mechanical milling (HEMM), and the resulting Cu6Sn5–TiC–C nanocomposite has been assessed as anodes for sodium-ion batteries. Composite anodes of Sn–C exhibit poor cyclic performance even with the introduction of 2 vol. % fluoroethylene carbonate (FEC) additive into the electrolyte. In contrast, Cu6Sn5–TiC–C nanocomposite anodes exhibit stable cycle life corresponding to a capacity retention of ∼80% at 40 cycles and high-rate performance with a capacity retention of ∼62% at 3000 mA g−1. These superior performance metrics is ascribed to the well-developed electrochemically active nanocrystalline material (Cu6Sn5) as well as a hybrid conductive matrix (TiC and C). The incorporation of 2 vol. % FEC additive into the electrolyte further improves the performance of Cu6Sn5–TiC–C nanocomposite to display a capacity retention of ∼94% at 250 cycles and high-rate capacity retention of ∼82% at 5000 mA g−1, which are attributed to the formation of a thin and stable SEI layer in presence of FEC.
Abstract Mining is excavation and recovery of ore and associated waste rocks from Earth's crust. The principle of mining is not to maximize ore production but to aim at zero waste generation and long-term sustainable development of nonrenewable wasting assets. The technology relies on rock competency, distance to surface, size, and orebody attributes, and is broadly grouped into surface and underground and soft and hard rock operations. Stoping is characterized by scale of mechanization, production capacity, productivity, postmining support, and cost per tonne of ore. Methods include open pit, underground soft bedded, and hard massive orebody. Mine access suites the technology during initial development. Production capacity and productivity increase with size of ore reserves, innovative cost-effective mining methods, and advanced mechanization. The procedure includes development, large diameter drilling, blasting, sizing, and transportation to in-house or third-party beneficiation plants. A standard-quality explosive improves the powder factor. Rock mechanic studies predict the best support system. Better mine ventilation improves the working conditions. Mine closure is an integral part within the legislative framework. A combination of in-house and commercial software provides the best possible design, execution, and product mix.