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In this work, detailed studies on Li dendrite formation in Li–S Batteries are reported. Li dendrites can grow rapidly, may pierce through or can easily grow around the separator. Dendrites can even lead to short circuits when cathode and/or anode are wrapped with the separator. By replacing the Li metal anode with a pre-lithiated Si anode, these dendrite problems could be successfully prevented and were not observed for more than 200 cycles. The here used Si microwire array anodes are examined with ether and carbonate based electrolytes and different charging conditions vs. a Li metal counter electrode and demonstrate very high capacities matching the theoretical values. Electrochemical pre-lithiated Si microwire array anodes are examined in full cells with binder free, sulfur infiltrated carbon nanotube cathodes (CNT-S) and various polysulfide or Li2S containing electrolytes. The average polysulfide chain length and the presence of LiNO3 in the electrolyte have a great impact on the cycle stability of the cell, next to the charging conditions. | battery |
As the deployment of solar and wind electrical energy increases, the intermittency of these power plants necessitates some means of energy storage for rebalancing the load and the supply. Storage of excess produced energy in electrochemical cells (batteries) is an obvious choice, and perhaps even the most practical method. However, the challenge is to find batteries that would be reliable, widely available, effective and cost-attractive. Within electrochemical storage the redox flow batteries constitute an important subgroup of storage and both the concepts and a number of redox systems is discussed here. The possible chemistries cover the more traditional vanadium redox flow cell. The modern trends are covered in the bromine-hydrogen, flow-through lead, zinc-bromine, cells with organic electrolytes and chemically regenerated redox fuel cells. A table comparing these systems is included. | battery |
Rechargeable lithium-air batteries offer great promise for transportation and stationary applications due to their high specific energy and energy density. Although their theoretical discharge capacity is extremely high, the practical capacity is much lower and is always cathode limited. A key for rechargeable systems is the development of an air electrode with a bifunctional catalyst on an electrochemically stable carbon matrix. The use of graphene as a catalyst matrix for the air cathode has been studied in this work. A Li-air cell using an air cathode consisting of nano-Pt on graphene nanosheets (GNS) has shown promising performance at 80% energy efficiency with an average capacity of 1200 mAh g−1 and more than 20 cycles without significant loss of total energy efficiency. Replacement of Pt with a bifunctional catalyst resulted in more than 100 cycles with an average capacity of 1200 mAh g−1 and total energy efficiency of about 70%. Electrochemical impedance spectroscopy data revealed increasing solution and charge transfer resistance during cycling, which hindered the cycle life. The increased solution resistance can be attributed to the evaporation and decomposition of electrolyte especially at high charge voltages. Further investigation on ionic liquid based electrolytes in Li-air systems is being conducted. | battery |
Early diagnosis of cognitive disorders in older adults is a major healthcare priority with benefits to patients, families, and health systems. Rapid advances in digital technology offer potential for developing innovative diagnostic pathways to support early diagnosis. Brief self-administered computerized cognitive tools in particular hold promise for clinical implementation by minimizing demands on staff time. In this study, we conducted a systematic review of self-administered computerized cognitive assessment measures designed for the detection of cognitive impairment in older adults. Studies were identified via a systematic search of published peer-reviewed literature across major scientific databases. All studies reporting on psychometric validation of brief (≤30 minutes) self-administered computerized measures for detection of MCI and all-cause dementia in older adults were included. Seventeen studies reporting on 10 cognitive tools met inclusion criteria and were subjected to systematic review. There was substantial variability in characteristics of validation samples and reliability and validity estimates. Only 2 measures evaluated feasibility and usability in the intended clinical settings. Similar to past reviews, we found variability across measures with regard to psychometric rigor and potential for widescale applicability in clinical settings. Despite the promise that self-administered cognitive tests hold for clinical implementation, important gaps in scientific rigor in development, validation, and feasibility studies of these measures remain. Developments in technology and biomarker studies provide potential avenues for future directions on the use of digital technology in clinical care.
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Short-range orders of Cd x Se70−x Te30 amorphous alloys of a chalcogenide system with 2≤x≤10 have been studied by wide-angle X-ray scattering (WAXS). Once the hypotheses on the local order of the alloy had been formulated, the radial distribution function (RDF) analysis have make it possible to evaluate them referring specifically to the coordination of the atoms. The structural parameters such as atomic distance between the different possible pairs of atoms in each element J(r), the structure factor F(q), the pair distribution function G(r) and the coordination numbers for amorphous samples have been discussed. Moreover, in our system, under study, the average coordination numbers of the three different atoms involved and their distance to the first coordination sphere have been determined. However, the extraction of the inverse Fourier transforms to generated atomic distribution function has led us to a simulated reduced interference function Q(q). | non-battery |
Nanostructured carbon materials, including carbon nanotubes, graphene and nanoporous carbon, show promise for expanding renewable energy. In particular, the configuration and electronic properties of graphene edges in relation with their electrochemical activity have become a major issue in carbon-based energy storage devices. Here, we review recent results concerning the important roles of graphene edges as the gateway for lithium ion intercalation in the anode of lithium-ion batteries, as promoters of high capacitance in carbon-based supercapacitors, and as anchoring sites for Pt nanoparticles in fuel cells. We envisage that the controlled synthesis of a specific, clean, and stable edge configuration could be achieved to maximize the electrochemical performance of nanostructured carbon-based energy storage devices. | battery |
Bismuth–vanadium oxyfluoride (Bi2VO5F) has been synthesized using a simple, solid-state reaction process at different sintering temperatures. The structure and performance of the samples have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge/discharge experiments. The results show that bismuth–vanadium oxyfluoride belongs to a tetragonal crystal system with space group I4mm. The sample that was synthesized at 550°C (P550) exhibits relatively good electrochemical properties. Sample P550 shows a high, initial discharge capacity of 222mAhg−1 at a rate of 100mAg−1 between 1.4 and 3.5V. Sample P550 also shows acceptable electrochemical cycling properties. After the first cycle, the discharge specific capacity remains between 106 and 155mAhg−1, which plateaus between 2.1 and 1.9V during the first 15 cycles. | battery |
Currently, there is a good deal of interest in the possibility that fuel cells will make an important contribution to world energy supplies for both mobile and stationary applications. This paper provides an up-to-date review of fuel cell technology. | battery |
A facile, rapid, and scalable method is developed for the fabrication of hierarchical CoFe2O4@graphene (CFO@GN) hybrid films on conductive substrates as a promising binder-free lithium-ion batteries anode. The obtained films show network morphologies, and almost all of the CFO nanoparticles are also homogeneously embedded into the layered graphene network. The resulting binder-free CFO@GN electrode with 35.85wt.% graphene exhibits excellent lithium storage performance with a high specific reversible capacity of 866.67 mAh g-1 at a high current densities of 1000mA g-1, and high rate capability. In addition, the reversible capacity can retain as high as 860 mAh g-1 and has no obvious decay after 200 cycles. This work supplies a versatile strategy for fabrication of other metal oxide@graphene hybrid films as an efficient way to improve the lithium storage performance. | battery |
Electrochemical properties of three perovskite oxides with different B-site elements, LaMnO3, La0.6Sr0.4FeO3 and LaNiO3, are examined with and without carbon using gas-diffusion electrodes, in comparison with our previous results on La0.5Sr0.5CoO3. Cyclic voltammetry studies reveal very low oxygen reduction current density of carbon-free perovskite oxides, indicating their poor catalytic activity on oxygen reduction reactions. By mixing carbon with perovskite oxides, the oxygen reduction current density is increased by about two orders. The results are consistent with the peroxide pathway mechanism in which the perovskite oxide is highly active on either electrochemical reduction or chemical decomposition. Electrochemical properties of a three-layered gas diffusion electrode demonstrate the peroxide pathway mechanism works even the perovskite oxide and the carbon exist in separate layers. Oxygen evolution reactions are prominently dependent on the oxide species and also on an addition of carbon. The electrode based on carbon-free LaNiO3 or La0.5Sr0.5CoO3 show moderate oxygen evolution activity, and the activity is further enhanced by an addition of carbon, while LaMnO3 and La0.6Sr0.4FeO3 show poor activity even with an addition of carbon. | battery |
A novel hybrid nanocomposite based on de-layered molybdenum disulfide (MoS2) by ionic-liquid (IL, [BMIM]BF4)-assisted exfoliation and graphene oxide (GO) was synthesized via a green, efficient, and high-quality method, which combined liquid-phase stripping method and ion-insertion method. In addition, an electrochemical sensor was developed using the MoS2-IL/GO nanocomposites for the determination of chloramphenicol (CAP). The morphology and structure of these synthetic materials were characterized by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and X-ray diffraction and the electrochemical characterization by cyclic voltammetry and electrochemical impedance spectroscopy. Based on this method, the insertion of IL can effectively exfoliate de-layered MoS2, and the MoS2-IL/GO nanocomposite exhibit 3D structure with higher surface area, excellent electrical conductivity, and synergistic catalytic capabilities. Under optimized conditions, the sensor responded linearly to CAP ranging from 0.1 to 400 µmol L−1 and the detection limit of 0.047 µmol L−1. In addition, the sensor showed excellent stability, repeatability, reproducibility, and selectivity, and has been applied to detect CAP in eyedrops, milk, and urine samples. | battery |
Cobalt ions, extracted from waste LiCoO2 by using a nitric acid leaching solution, are potentiostatically transformed into cobalt hydroxide on a titanium electrode and cobalt oxide is then obtained via a dehydration procedure. In linear sweep voltammetry, distinct cathodic current peak is observed and indicates that hydroxide ions are formed near the electrode via the electroreduction of dissolved oxygen and nitrate ions give rise to an increase in the local surface pH of the titanium. Under appropriate pH conditions, island-shaped cobalt hydroxide is precipitated on the titanium substrate and heat treatment of the cobalt hydroxide results in the formation of cobalt oxide. | battery |
Cadmium has been a significant threat to environment and human health due to its high toxicity and wide application in fossil-fuel burning and battery industry. Cyanobacteria are one of the most dominant prokaryotes, and the previous studies suggested that they could be valuable in removing Cd2+ from waste water. However, currently, the tolerance to cadmium is very low in cyanobacteria. To further engineer cyanobacteria for the environmental application, it is thus necessary to determine the mechanism that they respond to high concentration of cadmium. | non-battery |
The preparation of catalyst-coated membranes (CCMs) with two anodic catalyst layers (60% PtRu/C as catalyst) using a decal technique and their characterization by pseudo-half-cell measurements using both sides of the CCMs by simply turning the test cell around, allows the characterization of quasi-identical CCMs with a much smaller experimental uncertainty than observed for the classical direct methanol fuel cell (DMFC) testing of membrane electrode assemblies under similar working conditions (5 mV vs. 12 mV at a current density of 140 mA cm−2). With this new sensitive tool, we study the influence of the dispersing technology and the Nafion content on the performance of DMFC anodes. While the ionomer content shows a broad optimum between 20 and 40%, the dispersing technology does not have a strong impact on the fuel cell performance under the experimental conditions of this study, but influences strongly the stability of the catalyst slurries and the homogeneity of the electrode coatings.
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Effective integration of electrochemical devices consisting of enzyme-based biobatteries together with high power double-layer type capacitors is discussed here. An ultimate goal is to overcome a typical drawback of enzymatic power sources (biofuel cells and biobatteries): although their energy is potentially high enough to fulfill the needs of small electronic devices, their power is often too low. It is demonstrated that properly selected capacitor can support operation of such a low power device simply by supplying appropriate power pulses with fast dynamic response that is required for many applications involving fluctuating loads. Our model integrated system is obtained by coupling a series of double-layer capacitors with well-behaved zinc/oxygen biobattery. The biobattery utilizes a stable cathodic material composed of covalently phenylated single-walled carbon nanotubes and the oxygen reduction enzyme, laccase, together with the hopeite-covered zinc rod acting as the anode. The enzymatic power source was characterized by the maximum power density of 1.8 mW cm−2, the open circuit voltage of 1.6 V. Nevertheless, under the 50 Ω loading, the voltage of biobattery (electrode surface areas of ca. 0.3 cm2) drops to 0 V after 2 s. The practical performance (power stability) of a biobattery has significantly improved by its parallel connection to electrochemical capacitor. The importance of such capacitor’s parameters as low resistance (not more than a few hundred of milliohms), proper capacitance, and leakage current (not higher than a few microamperes) is emphasized here. The potential utility of the optimized biobattery/supercapacitor system is discussed in terms of use as a source of power to operate a digital watch. | battery |
This work reports the preparation of a V-doped Li4Ti5O12/C (donated as V-doped LTO/C) composite material, applying a solid-state method. Both metal doping and carbon coating are applied on the Li4Ti5O12 material, enhancing its rate capability and cycle stability. Furan polymer is used as a carbon source, and vanadium (V) is selected as a dopant. The properties of the materials are examined by X-ray diffraction (XRD), micro-Raman, scanning electron microscopy (SEM), high-resolution transmission microscopy (HR-TEM), the AC impedance method, and the galvanostatic charge/discharge method. For comparison, Li4Ti5O12/C composite materials with and without V doping are also examined. The Li4Ti4.90V0.10O12/C composite material achieves discharge capacities of 165.59 and 76.76 mAh g−1 at a 0.2/1C and 0.2/20C rate, respectively. A Li4Ti5O12/LiFePO4 full cell (LTO capacity-limited) is constructed and investigated. The full cell exhibits discharge capacities of 181, 178, 167, 142, 110, and 78 mAh g−1 at 0.2, 0.5, 1, 3, 5, and 10C, respectively. We determine that the Li4Ti4.95V0.05O12/C composite anode is an outstanding candidate for application in high-power Li-ion batteries. | battery |
The titration of the interfacial capacitance of a C-cloth electrochemical capacitor electrode was undertaken for the purpose of evaluating the cyclic voltammetry (CV) responses as a function of the pH of an aqueous electrolyte over the range of 0–14. As the pH was increased from 0 (aqueous H2SO4) to a progressively more alkaline (NaOH) solution of pH 11, a 30% loss in capacitance is seen, partly attributable to the disappearance of the pseudocapacitive peaks based on the oxidation/reduction of the surface quinone groups. As the pH is increased above 11, the capacitance increases ca. 20%, as other surface functionalities (a pyrone derivative and another unknown species) become activated in alkaline solution. When the C-cloth is titrated from pHs of 14 to 2, the CV current profile shrinks (with a concomitant decrease in charge-storage capacity). However, at electrolyte pHs below ca. 2, the quinone functionalities are activated and the charge-storage capacity increases ca. 30% above the initial value. It was found that the CV current responses in pH 14 electrolytes are smaller when the titration is base-initiated, rather than acid-initiated, due to an activation step required to make the pyrone functionalities active in alkaline solution. | battery |
Knowledge of groundwater contamination sources is critical for effectively protecting groundwater resources, estimating risks, mitigating disaster, and designing remediation strategies. Many methods for groundwater contamination source identification (GCSI) have been developed in recent years, including the simulation–optimization technique. This study proposes utilizing a support vector regression (SVR) model and a kernel extreme learning machine (KELM) model to enrich the content of the surrogate model. The surrogate model was itself key in replacing the simulation model, reducing the huge computational burden of iterations in the simulation–optimization technique to solve GCSI problems, especially in GCSI problems of aquifers contaminated by dense nonaqueous phase liquids (DNAPLs). A comparative study between the Kriging, SVR, and KELM models is reported. Additionally, there is analysis of the influence of parameter optimization and the structure of the training sample dataset on the approximation accuracy of the surrogate model. It was found that the KELM model was the most accurate surrogate model, and its performance was significantly improved after parameter optimization. The approximation accuracy of the surrogate model to the simulation model did not always improve with increasing numbers of training samples. Using the appropriate number of training samples was critical for improving the performance of the surrogate model and avoiding unnecessary computational workload. It was concluded that the KELM model developed in this work could reasonably predict system responses in given operation conditions. Replacing the simulation model with a KELM model considerably reduced the computational burden of the simulation–optimization process and also maintained high computation accuracy. | non-battery |
A simulation model for modeling photovoltaic (PV) system power generation and performance prediction is described in this paper. First, a comprehensive literature review of simulation models for PV devices and determination methods was conducted. The well-known five-parameter model was selected for the present study, and solved using a novel combination technique which integrated an algebraic simultaneous calculation of the parameters at standard test conditions (STC) with an analytical determination of the parameters under real operating conditions. In addition, the simulation performance of the model was compared with other models, and further validated by outdoor tests, which indicate that the proposed model fits well the entire set of experimental field test I–V curves of the PV module, especially at the characteristic points. After validation, this model was employed to predict the PV system power output under real conditions. The results show that the predictions agree very well with the PV plant field collected data. Thus, the operating performance of a standalone PV system located on a remote island in Hong Kong has been further evaluated with the aid of this model. It is found that the PV array power output is restricted by the status of the battery bank. This research demonstrates that the PV simulation model developed during the study is simple, but very helpful to PV system engineers in understanding the I–V curves and for accurately predicting PV system power production under outdoor conditions. | battery |
The degradation and failure of Li-ion batteries is strongly associated with electrode microstructure change upon (de)lithiation. Now, an operando X-ray tomography approach is shown to correlate changes in the microstructure of electrodes to cell performance, and thereby predict degradation pathways.
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Gallium electrodeposition onto vitreous carbon was studied in chloride solution using potentiostatic and potentiodynamic techniques. The morphology and composition of the deposits were analysed by SEM/EDX. The effects of solution pH, applied potential and the hydrodynamic conditions on the electroreduction process were investigated. Results indicate that the reduction to Ga+1 species takes place at the lower overpotentials, while at high overpotentials gallium deposition occurs through progressive nucleation and growth under diffusion control. The influence of the simultaneous hydrogen evolution reaction on the electrodeposition process is discussed.
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An asymmetric supercapacitor (ASC) uses very thin petal-shaped MnO2 nanosheets as the positive electrode and a network of carbon nanotube-embedded polyacrylonitrile-based carbon nanofibers (CNT-CNF electrodes) as the negative electrode. It has a high specific capacitance and a high specific energy density in 0.5 M Na2SO4. An assembled MnO2//CNT-CNF ASC is operated reversibly at a high cell voltage of 2.0 V and exhibits a high specific capacitance of 93.99 F g−1 and an excellent energy density of 52.22 Wh kg−1, which is better than those of ASCs that are based on MnO2//carbon, which can be found in the literature. The MnO2//CNT-CNF ASC has superior cycling stability with 92% retention of initial specific capacitance after 2000 cycles. | battery |
Coulombic efficiency (CE) has been frequently used to assess the cyclability of newly developed materials for lithium metal batteries. The authors argue that caution must be exercised during the assessment of CE, and propose a CE testing protocol for the development of lithium metal batteries.
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Laser physical vapor deposition is used to deposit thin films of lithium phosphorous oxynitride in nitrogen and lithium nickel manganese oxide in oxygen ambient on Si substrate. LIPON film is also deposited on LiNiMnO film that is deposited on Si. Graphene films consisting of graphene platelets are deposited on Si substrate from a suspension in isopropyl alcohol. Li-graphene films are obtained after Li adsorption by immersion in LiCl solution and further drying. Transient thermo reflectance signal is used to determine the cross-plane thermal conductivity of different layers and interface thermal conductance of the interfaces. The results show that LIPON film with lower thermal conductivity is a thermal barrier. The interface thermal conductance between LIPON and Au or Si is found to be very low. Thermal conductivity of LiNiMnO is found to be reasonably high so that it is not a barrier to thermal transport. Film with graphene platelets shows a higher value and Li adsorbed graphene film shows a much higher value of cross-plane thermal conductivity. The value of interface thermal conductance between graphene and Au or Si (100) substrate is also much lower. The implications of the results for the thermal transport in thin film Li batteries are discussed. | battery |
A novel data logger incorporating a 3-axis gyroscope, a 3-axis accelerometer, and a 3-axis magnetometer was developed and externally attached to Japanese amberjacks, Seriola quinqueradiata, to investigate the possibility of using this device for monitoring the movement performance of the fast-start behaviour of fish in the field. Triggered escape behaviours were measured simultaneously by the data logger (500Hz) and a high-speed camera (200Hz) in a tank. By using a gyroscope, the data logger accurately reconstructed the gravity-based acceleration, 3-dimensional attitude, dynamic acceleration, and angular velocity of fish during the fast-start movement, which was impossible by previous methods using only an accelerometer and a magnetometer; these variables can therefore be used to assess the distance-related performance and manoeuverability of fish. The escape movements can be categorised into two mechanical types (single- and double-bend) using the obtained locomotor variables, which showed significant differences between movement types. These results indicate the possibility of using this animal-mounted data logger to quantify the movement performance of the fast-start behaviour of fish in nature. | non-battery |
Stack reliability is of great importance in commercialization of vanadium redox flow battery (VFB) since practical VFB stacks are prone to undergo material failure and electrolyte leakage caused by unreliable stack design and improper assembling conditions. A comprehensive evaluation of mechanical behavior and analysis of stack failure is thus highly valued for material fabrication, stack design and assembly. In this study, mechanical behavior and Weibull statistics based failure analysis of the VFB stacks are investigated. The Weibull parameters of two key components are firstly determined from tensile strength tests, which, in combination with finite element analysis of the stack mechanical behavior, are subsequently used to calculate the stack failure probability at specified clamping forces for two different stack designs that both contains 20 individual cells. The results demonstrate that the stack failure probability can be significantly reduced by properly decreasing the clamping forces for both designs, while adding a thick plate to the middle of the stack can effectively lower the probability of failure thus offering a superior stack mechanical performance and a prolonged stack life cycle. Such an approach to analyze stack failure can be readily accessed by flow battery engineers for design and assembly of commercial VFB stacks. | battery |
This paper firstly reports a facile hydrothermal method to prepare CuFeS2 spike-like nanorods as a promising anode material for lithium ion batteries. When being evaluated as an anode material in traditional carbonate-based (EC/DEC/DMC) and ether-based (DOL/DME) electrolytes, it's found that the type of the electrolytes plays a key role in contribution to the electrochemical performance. The CuFeS2 binary mental sulfide material has initial discharge capacities of 632.6mAh/g in the carbonate-based electrolyte and 674.9mAh/g in the other at the rate of 0.2C. After 50 circles, the discharge capacity decays severely, down to 64.3mAh/g while the one performed in the ether-based electrolyte still possesses a capacity of 425.3mAh/g, whose capacity retention is far more higher. Besides, an outstanding rate capability (∼190mAh/g) can be obtained at a high rate of 10C in the ether-based electrolyte, which is indicative of becoming promising anode materials for high-rate lithium batteries. | battery |
Olivine–LiCoPO4 powders have been processed by mechanical grinding for time periods ranging from 0.5 to 10h with conductive carbon contents of 0, 8 and 20% (w/w). In all cases the grinding process produces an amorphization of the crystalline materials and decreases both the crystallite and particle sizes. Secondary phases are detected by scanning electron microscopy and X-ray diffraction in the materials milled for times greater than 2h without carbon. The addition of conductive carbon during the milling process decelerates the degradation of the material and secondary phases are not detected even after 10h of grinding. The electrochemical performance of olivine–LiCoPO4 is improved in all the materials milled for 0.5h; a lower cell polarization and a larger reversible specific capacity are observed. These characteristics are enhanced in the materials grinded with conductive carbon, which also display a capacity retention with cycling clearly superior to that of the fresh LiCoPO4. Ball milling LiCoPO4 for times greater than 1h is detrimental for the response of the electrode, independently on the amount of conductive carbon in the grinding media. | battery |
It has been established that addition of carbon additives to the lead negative active material (NAM) of lead-acid batteries increase battery charge acceptance in hybrid electric vehicle mode of operation. The present work studies three types of activated carbons and two types of carbon blacks with the aim to evaluate their efficiency in improving the charge acceptance of lead-acid batteries. It has been established that the size of carbon particles and their affinity to lead are essential. If carbon particles are of nanosizes, they are incorporated into the bulk of the skeleton branches of NAM and may thus increase the latter's ohmic resistance. Their content in NAM should not exceed 0.2–0.5wt.%. At this loading level, carbon grains are adsorbed only on the surface of NAM contributing to the increase of its specific surface area and thus improving its charge acceptance. When carbon particles are of micron sizes and have high affinity to lead, they are integrated into the skeleton structure of NAM as a structural component and act as super-capacitors, i.e. electric charges are concentrated in them and then the current is distributed along the adjacent branches of the lead skeleton with the lowest ohmic resistance. This eventually improves the charge acceptance of the negative battery plates. | battery |
Novel Sb2S3@multiwalledcarbonnanotubes(MWCNTs) (SM) composites were synthesized via a facile and green method which included an in-situ growth of Sb2S3 nanoparticles on the surface of MWCNTs through precipitation and subsequent thermal treatment. The morphologies and structures of SM composites were tested by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and nitrogen adsorption and desorption isotherms. Finally, their application as anode materials for sodium-ion batteries (SIBs) was investigated through corresponding electrochemical measurements such as galvanostatic charge/discharge tests, cyclic voltammetry and electrochemical impedance spectroscopy. The results show that the SM composites display higher capacity, better cycling stability and superior rate performance than pure Sb2S3, and a capacity of 412.3mAhg−1 after 50 cycles at 50mAg−1 is obtained for SM composites with 30wt.% MWCNTs loading. The enhanced performance is ascribed to an increase in the specific surface area, an improvement in the charge transfer and effective buffering of the volume change offered by the porous conductive network structure of the composite with the introduction of MWCNTs. | battery |
M.M., a right-handed, 74 year old professional musician and composer, presented with a progressive aphasia with a severe anomia. His musical competence was apparently totally preserved, and he continued his activity as a composer. There was a striking discrepancy between his impaired naming of nonmusical stimuli and his normal naming of musical instruments' sounds. We suggest that the preservation of skills in the musical domain results from an expanded cortical representation of this function in the left hemisphere, secondary to his lifelong formal training, and to the high level of his professional competence. As for his preserved naming of musical instruments, we argue that the early age-of-acquisition and higher than “normal” frequency/familiarity for names of musical instruments facilitate the access to their lexical representation and/or their retrieval within the lexicon. | non-battery |
Three-dimensional (3D) hollow nanostructure has been intensively investigated for preparing desirable anode material. Herein, VN hollow spheres are made up of porous nanosheets which were prepared through a one-step solvothermal route and followed with calcination process under ammonia atmosphere. Consequently, the obtained hollow sphere structure can provide large surface area and exhibiting unprecedented stable long cycling performance (456 mA h g−1 after 1100 cycles), when applied as an anode for lithium intercalation. Besides, the anode material also demonstrates a high capacitive contribution of 76.1% at 2 mV s−1 for the total charge. | battery |
The recent literature on applied energy has emphasized the role of energy storage in the electricity supply chain. However, absence of an integrated valuation framework for services provided by energy storage technologies, owed to its limited scope so far, hinders investments in such capital intensive systems. To this end, the feasibility of an alternative operation strategy for energy storage systems (ESSs), based on the use of wind energy surplus, is currently investigated. More precisely, valuation of the policy options available to promote wind-based ESSs is carried out, by employing, for the first time, a comprehensive socioeconomic cost-benefit model that takes into account – among others – initial investment subsidies and feed-in tariffs (FiTs) for ESSs. Pumped hydro and compressed air energy storage covering peak demand are examined, demonstrating that such systems may prove cost-effective if “socially just” FiTs are applied, with our findings however, also supporting the notion that a portfolio of policies can more effectively facilitate investments in the sector. | battery |
Since the first practical uses of fuel cells were developed, it has become clear that they could find use in many products over a wide power range of milliwatts to tens of megawatts. Throughout the 1990s, and later, there has been significant work carried out on adapting the various different fuel cell technologies for use in targetted consumer and industrial applications. This paper discusses these developments and gives details on the specific market segments for providing power to vehicles, portable devices and large- and small-scale stationary power generation. | battery |
We report a feasible design to fabricate micrometer-scale Si films deposited on nanostructured Cu foil as high areal capacity anodes for Li-ion batteries with excellent cycling performance. Nanostructured copper oxides are prepared by anodic oxidation of Cu foil in alkaline solution. The resultant copper oxide nanofibers function as matrix for thick Si films (1–2 μm) loading. Metallic Cu nanofibers are obtained by in-situ electrochemical reduction at low potentials, which work as electrical highways for fast electron transport and a reliable mechanical matrix to accommodate volume changes during lithium–silicon alloy/dealloy processes. The engineered thick Si film anode exhibit both high areal capacity (0.48 mAh cm−2 for 1 μm Si film and 0.6 mAh cm−2 for 2 μm Si film after 200 cycles at 0.225 mA cm−2) and excellent rate capability (0.52 mAh cm−2 at 1.05 mA cm−2 for 2 μm Si film). The 2 μm silicon film electrode is able to recover to the initial value of 1 mAh cm−2 when the current rate is set back to 0.15 mA cm−2 even after cycling at high current rates. The reported concept can be a general method for high-loading-film electrodes, which is industrial scalable and compatible with current battery manufacturing processes. | battery |
Biogenic 3-D SiO2 micro-assemblies (diatom microshells) of low specific surface area (SSA, <2 m2g−1) have been transformed into 3-D replicas of high SSA C (>1300 m2g−1) and Pt-loaded C (>600 m2g−1) by a shape-preserving serial reaction process. Such high SSA micro-assemblies may be generated in a wide variety of selectable 3-D shapes for tailored catalysis, filtration, or adsorption for energy storage/production, water purification, and biofuel separation.
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This study of 118 students who placed into basic skills sections of College English suggests that students’ self-beliefs may be a particularly important predictor of success in weak writers in first-semester courses. Two types of writing self-efficacy scales—a writing tasks/skills scale and an approach-to-writing scale—were developed to follow current composition practice more closely. Locus of control was the single most powerful predictor of success. This finding is congruent with theory about the importance of locus of control in new and ambiguous situations. High school performance, writing proficiency, and negative academic behaviors were also significant factors in regression analyses for both course grade and writing proficiency test. Various ways that writing instructors can help improve students’ self-beliefs are discussed. | non-battery |
The development of environmentally clean and energy-efficient coal-based power plants is of strategic importance to meet the increasing demand for more energy and clean air in the future. Carbon–air fuel cells (CAFCs) are a promising class of clean, efficient and sustainable power generators fueled by an abundant, cheap and sometimes renewable fuel source – coal, biomass, municipal waste, and other forms of solid carbons, with low emissions of CO2, NOx, SOx and VOCs. Because of the inherent thermodynamic and environmental advantages, CAFCs have garnered much interest in recent decades. In this article, we review recent advances in material development for catalysts/anodes and novel designs of various types of CAFCs. Fundamental understanding of the mechanisms and rate-limiting steps in carbon conversion is also discussed in detail. Finally, the review is concluded with promises and challenges of CAFCs.
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LiNi0.5Mn1.5O4 as a 4.7V-class cathode material was prepared through the radiated polymer gel method that allowed homogeneous mixing of starting materials at the atomic scale. After calcinations of the polymer gels containing the metal salts at different temperatures from 750 to 1150°C, powders of a pure LiNi0.5Mn1.5O4 phase were obtained. X-ray diffraction and transmission electron microscopy were used to characterize the structures of the powders. Galvanostatic cell cycling and a simultaneous DC resistance measurement were performed on Li/LiNi0.5Mn1.5O4 cells. It is found that the powder calcined at 950°C shows the best electrochemical performance with the initial discharge capacity of 139mAhg−1 and 96% retention after 50 cycles. Adopting a slow cooling procedure for the powder calcination can increase the capacity of LiNi0.5Mn1.5O4 at the 4.7V plateau. Besides, a “w”-shape change of the DC resistance of Li/LiNi0.5Mn1.5O4 cells is a good indication of the structural change of LiNi0.5Mn1.5O4 electrode during charge and discharge courses. | battery |
A facile electrochemical route was applied to prepare polypyrrole (PPy)/anthraquinone sulfonate (AQS)/reduced graphene oxide (r-GO) composite. The as-synthesized composite showed an interconnected porous structure, which is related to the competitive relationship between two dopants. The cyclic voltammograms and electrochemical impedance spectra confirmed that the presence of highly conductive r-GO in PPy matrix ensured an efficient redox reaction obtained for redox-active AQS. As a result, the PPy/AQS/r-GO composite exhibited an enhanced specific capacity of 127.2 mAh g−1 with ca. 100% coulombic efficiency at 0.1 A g−1. Furthermore, the superior rate capability and cycling stability were also observed for PPy/AQS/r-GO, compared to AQS doped PPy. It is possible to adopt this co-dopants system for creating electro-active polymer materials with high capacities that are comparable to that of conventional inorganic intercalation electrode materials. | battery |
Although performance of LiS batteries with various carbon/sulfur composites has been wildly explored at room temperature, the reports studying the behaviors of LiS cathodes at low temperature are few. Herein, a novel multifunctional graphene oxide-Zn(II)-triazole complex (denoted as GO-Zn(II)-AmTZ) with excellent property at low temperature(-20 °C) is successfully prepared. In GO-Zn(II)-AmTZ, the metal ions (Zn(II)), amine groups and the N penta-heterocycle are introduced synchronously, leading improvement of LiS performance at both room and low temperature. As a result of the multifunctional arrangement, GO-Zn(II)-AmTZ cathodes could provide a discharge capacity of 315 mAh g−1 (0.5C) after 100 cycles at −20 °C. A capacity of ∼520 mAh g−1 is achieved over 300 cycles at room temperature with low capacity attenuation rate at current rate of 0.5C. The improved performance is speculated to the contribution of enhanced polysulfide immobilization of GO-Zn(II)-AmTZ modified by the Zn(II), amine groups and the N atoms. | battery |
The inherent electrochemical performance of supercapacitor electrodes is highly depends on their structures, therefore, numerous efforts are focus on rationally designing and constructing supercapacitor electrodes with hierarchical structures. In this work, we report a facile method for controllable synthesis of hierarchical shell-core structures by anchoring NiO nanospines on concave spherical carbon particles. It is observed that the inner carbon core, acting as a highly efficient current collector, is inherited from the calcination of concave spherical sulfonated polystyrene, while the external shell, resulting from these NiO nanospines, plays the role of active materials. Benefiting from the hierarchical shell-core structures with large specific surface area, additional electroactive sites, reduced interior space, short ions diffusion pathway and intimate electrode/electrolyte contacts, the as-synthesized electrodes exhibit superior electrochemical performance, such as high specific capacitance (1161 F g−1 at a current density of 2 A g−1), good rate capability (839 F g−1 at a high current density of 10 A g−1) as well as long cycling stability (92.4% retention after 3000 cycles at 2 A g−1). We believe that the electrodes are expected to be the most promising candidate for supercapacitors, and more importantly, this strategy plays an important role in the construction of novel hierarchical shell-core structures with superior electrochemical performance for advanced energy storage materials. | battery |
The enhancement of Ga incorporation into the CIGS thin film by electrodeposition has been realized. One-step electrodeposition Cu(In,Ga)Se2 thin films under different hydrogen peroxide (H2O2) concentrations was investigated. The ratio Ga/(In+Ga) and characteristics of thin films were further modulated by adding H2O2 into electrolyte. The mechanism of the effects of H2O2 on electrodeposition Cu(In,Ga)Se2 thin films was illustrated using a schematic diagram. And this mechanism was proved by cyclic voltammograms, potentiostatic polarization, energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM) and Raman spectra. The films were found to have the same basic chalcopyrite structure of CuInSe2, and have the widen band gap (UV-VIS-NIR spectrophotometer) after adding H2O2 into the electrolyte. The evidence of Ga incorporation increment can be observed from the peak shift of Raman spectra and widen band gap. | battery |
The solar insolation received on earth have different components in which power is embedded. Out of many, visible spectrum and thermal spectrum are separately used to harvest energy through solar thermal or solar photovoltaic systems respectively. Photovoltaic (PV) panels are reported to experience undesirably high temperature rise due to heat accumulation from solar radiation which is not actively converted into electricity. This undesirable heat decreases conversion efficiency of PV panels. Thermoelectric module (TEM) in coordination with PV panel is proposed to recover and convert this waste heat energy to useful electrical energy. This paper demonstrates the capability of proposed system for electrical power generation from waste heat developed in PV panel in addition to generation from PV systems. Dynamic model of photovoltaic thermoelectric hybrid (PTH) system is developed in SIMULINK/ MATLAB environment based on electrical and thermal characteristics of the material. Simulation results for maximum energy harvesting for PTH system are presented under dynamic perturbations in solar radiations. Proposed control scheme ensures maximum energy harvesting without allowing system to operate at temperature out of prescribed limits for PV or TEM. It has been observed in the simulation that PTH system effectively handles the load and source transitions, which validates the scheme. | battery |
Many commonly used measures of figural reproduction have been found to be relatively insensitive to the effects of right temporal lobe dysfunction. More positive findings are present in studies using measures of figural learning over repeated trials. This study examined the use of a commercially available measure of figural learning in a sample of epilepsy patients undergoing presurgical neuropsychological testing. The Brief Visuospatial Memory Test—Revised (BVMT-R) was administered to 47 subjects undergoing comprehensive presurgical workups with video and EEG monitoring. Groups with left (N=25) and right (N=22) temporal lobe seizures did not differ on BVMT-R measures of learning, delayed recall, or yes/no recognition. Approximately 29% of the sample exhibited “impaired” performance in comparison to published norms. The results of receiver operating curve analyses revealed little discrimination in performance between groups. The BVMT-R does not appear to have the sensitivity required for assessing nonverbal memory in this population. | non-battery |
Battery polarisation is not only responsible for reducing battery available capacity but also for controlling heat generation characteristics of batteries. This phenomenon was therefore carefully studied and modelled by Newman, Tiedemann and Gu (NTG). The NTG model is now widely used for simulating battery thermal behaviour and has even been adopted by CD-adapco for their proprietary battery modelling software - Battery Design Studio. The model however revolves around an idealised battery cell. It may thus not be applicable to commercial battery cells. This paper scrutinises the effect of open circuit voltage (OCV), a key parameter in the NTG model, on the irreversible heat generation of a commercial cell under a controlled environment by differentiating the OCV recorded immediately after the current stops flowing through the cell and the OCV corresponding to the equilibrium state of the cell. It is noticed that the NTG model underestimates the irreversible heat generation rates for a 20 Ah Li-ion pouch cell by approximately 0.15 W and 0.22 W for discharge currents at 0.33C and 0.5C at an operating temperature of 27 °C, respectively. It is also observed that the accuracy of the NTG model is significantly improved in simulating thermal behaviour of commercial battery cells when the OCV is representative of the cell equilibrium voltage. | battery |
Reduced graphene oxide (rGO) has attracted wide attention as anode materials of lithium ion batteries, however, restacking of rGO sheets limits its capacity and rate performance. To address this issue, a sandwich-like composite of N-doped carbon (NDC) and rGO (rGO@NDC) was fabricated via a process of absorbing [EMIm]N(CN)2 ionic liquid on the surface of graphene oxide (GO) nanosheets and subsequent heat-treating of the composite. The rGO@NDC composite exhibits a high specific capacity of 409.4 mAh g−1 with a Coulombic efficiency of 100% after 50 cycles at a charge-discharge rate of 0.5 C, and a specific capacity of 222.8 mAh g−1 with no capacity fade after 1200 cycles at charge-discharge rate of 10 C. Compositing the rGO with NDC particles can decrease the superficial oxygen-containing functional groups of the rGO, and therefore decrease side reactions during battery cycling. And embedding of NDC particles on the surface of rGO sheets avoids the restacking of rGO sheets and enlarges the interlayer space of the rGO to facilitate Li+ transport within the rGO@NDC. Finally, the NDC particles provide more accessible sites for Li+, and rGO sheets as conductivity networks improves electron transport. | battery |
The gas generation associated with the use of the lithium bis(oxalate)borate—(LiBoB) based electrolyte at the elevated temperature were detected in the pouch cell (MCMB/LiNi1/3Co1/3Mn1/3O2 with 10% excess Li), which might prevent the LiBoB usage as a salt. However, the cell capacity retention was improved significantly, from 87 to 96% at elevated temperature, when using LiBoB as an electrolyte additive. The capacity fade during cycling is discussed using dQ/dE, area specific impedance, and frequency response analysis results. Most of the capacity loss in the cell is associated with the rise in the cell impedance. Moreover, results from the differential scanning calorimetry indicate that the thermal stability of the negative electrode with the solid electrolyte interface (SEI) formed by the reduction of the LiBoB additive was greatly improved compared with that obtained from the reduction of LiPF6-based electrolyte without additive. In this case, the onset temperature of the breakdown of the LiBoB-based SEI is 150°C which is higher than that of the conventional electrolyte without additive. Furthermore, the total heat generated between 60 and 170°C is reduced from 213 to 70Jg−1 when using LiBoB as electrolyte additive compared to the one without additive. In addition, the thermal stability of the charged LiNi1/3Co1/3Mn1/3O2 with 10% excess Li was not affected when using LiBoB as an electrolyte additive. | battery |
Objective Interference with brain rhythms by noninvasive transcranial stimulation that uses weak transcranial alternating current may reveal itself to be a new tool for investigating cortical mechanisms currently unresolved. Here, we aim to extend transcranial direct current stimulation (tDCS) techniques to transcranial alternating current stimulation (tACS). Background Parameters such as electrode size and position were taken from those used in previous tDCS studies. Methods Motor evoked potentials (MEPs) revealed by transcranial magnetic stimulation (TMS), electroencephalogram (EEG)-power, and reaction times measured in a motor implicit learning task, were analyzed to detect changes in cortical excitability after 2-10 minutes of AC stimulation and sinusoidal DC stimulation (tSDCS) by using 1, 10, 15, 30, and 45 Hz and sham stimulation over the primary motor cortex in 50 healthy subjects (eight-16 subjects in each study). Results A significantly improved implicit motor learning was observed after 10 Hz AC stimulation only. No significant changes were observed in any of the analyzed frequency bands of EEG and with regard to the MEP amplitudes after AC or tSDCS stimulation. Similarly, if the anodal or cathodal DC stimulation was superimposed on 5, 10, and 15 Hz AC stimulation, the MEP amplitudes did not change significantly. Conclusions Transcranial application of weak AC current may appear to be a tool for basic and clinical research in diseases with altered EEG activity. However, its effect seems to be weaker than tDCS stimulation, at least in the present context of stimulus intensity and duration. Further studies are required to extend cautiously the safety range and uncover its influence on neuronal circuitries. | non-battery |
Publisher Summary This chapter provides an overview of the global plastics industry today and tomorrow. It indicates the orders of magnitude of global plastics consumption. It also shows the market shares by weight of the main thermoplastics versus total thermoplastics in the main industrialized countries. It presents schematically the approximate market shares consumed by different application sectors for plastics as a whole. The consumption of thermoplastics predominates but the market share distribution of the thermoplastic application sectors is nevertheless somewhat different from that of plastics as a whole. For each type of polymer, there are several possible processing methods from which it will be necessary to choose to best suit the required geometries, production rates, targeted properties and economic context. The study reports the consumption of the major thermoplastics in 2005 for the three main geographic areas, together with market shares and average annual growth rates (AAGR). These identified thermoplastics represent roughly 70% of the overall global consumption of plastics. Polymeric materials are intrinsically expensive, but their use becomes appealing if one takes into account the processing costs, the new technical possibilities that they permit and the total cost at the end of their lifetime. | non-battery |
Patient acceptance is one of the major barriers toward widespread use of mHealth systems. The aim of this study was to assess system operability and whole trial feasibility, including patients’ experience with their use of COMMODITY12 mHealth system under. Secondary study aims included assessment of several metabolic parameters as well as patient adherence to the treatment. This was a prospective parallel-arm randomized controlled trial in outpatients diagnosed with DM2, being treated in the primary care settings in Lodz region, Poland, with 6 weeks period of follow-up. Patients opinions were collected with 7-item questionnaire, assessing different aspects of system use, as well as EuroQol-5D-5 L questionnaire, assessing health-related quality of life. Sixty patients (female, 24, male, 36, mean age +/− SD 59.5 +/− 6.8) completed study. All four layers of the COMMODITY12 system proved to work smooth under real-life conditions, without major problems. All dimensions of experience with system use were assessed well, with maximum values for clearness of instructions, and ease of use (4.80, and 4.63, respectively). Health related quality of life, as assessed with cumulative utility measure, improved significantly in COMMODITY12 system users (P < 0.05). mHealth system modestly improved glycaemic and blood pressure control, assuring high level of patient adherence with overall adherence reaching 92.9 %. Study proved that the COMODITY12 system is well accepted by type 2 diabetes patients taking part in clinical trial, leading to several clinical benefits, and improved quality of life. Nevertheless, before future commercialisation of the system, several minor problems identified during the study need to be addressed. | non-battery |
The spinel Li4Ti5O12 has been doped by Na for the purpose of improving its cycle performance as an anode. The lattice parameter of Li4Ti5O12 increases due to the Na doping. SEM shows that all materials are well crystallized with a particle size in the range of 400–600 nm. The pristine Li4Ti5O12 sample has a bigger particle size than that of Na-doped samples. Although the doping does not change the crystallographic structure of Li4Ti5O12, they exhibit better cyclability at high charge–discharge rate compared with pristine Li4Ti5O12. Li3.85Na0.15Ti5O12 gives the best cycling performance, only 11.1% loss of capacity after 80 cycles at 2 C charge–discharge rate. Na-doped Li4Ti5O12 exhibits lower potential separation, indicating faster electron transfer kinetics and cycling reversibility. Electrochemical impedance spectroscopy demonstrates that the improved performance of the Na-doped Li4Ti5O12 is due to a small decrease in the charge transfer resistance, indicating high electrochemical activity during cycling. The excellent cycling and safety performance of the Na-doped Li4Ti5O12 electrodes are found to be due to the significantly increased ionic and electronic conductivity. Since fast charge–discharge performance is an important factor that needs to be considered in fabricating power batteries in industry, the Na-doped Li4Ti5O12 materials moves closer to real and large scale applications. | battery |
Wet ball-milling route is employed to prepare sulfur-carbon nanotubes composites. The influences of solvents, including ethanol and chloroform, on the structure and electrochemical performance of the composites are firstly investigated. As compared to the conventional dry-milling process, high loose structure and uniform distribution of sulfur can be obtained by adding ethanol during the ball-milling process, and significant enhancement of electrochemical performance is presented. At the current density of 800mAg−1, the discharge capacity can be stably retained at 861.6mAhg−1 after 150 cycles for the composite prepared by adding ethanol, showing obvious advantages over the dry-milling sample and the composite prepared by adding chloroform. When the current density increase to 1600mAg−1, it can still demonstrate a high reversible capacity of 640.9mAhg−1 after 200 cycles. Furthermore, the influence of ball-milling speed is also investigated, but a low utilization of sulfur active materials is obtained after high-energy ball milling process. | battery |
Long-term effects of endocrine disruptors (EDs) on aquatic invertebrates remain difficult to assess, mainly due to the lack of appropriate sensitive toxicity test methods and relevant data analysis procedures. This study aimed at identifying windows of sensitivity to EDs along the life-cycle of the freshwater snail Lymnaea stagnalis, a candidate species for the development of forthcoming test guidelines. Juveniles, sub-adults, young adults and adults were exposed for 21 days to the fungicide vinclozolin (VZ). Survival, growth, onset of reproduction, fertility and fecundity were monitored weekly. Data were analyzed using standard statistical analysis procedures and mixed-effect models. No deleterious effect on survival and growth occurred in snails exposed to VZ at environmentally relevant concentrations. A significant impairment of the male function occurred in young adults, leading to infertility at concentrations exceeding 0.025 μg/L. Furthermore, fecundity was impaired in adults exposed to concentrations exceeding 25 μg/L. Biological responses depended on VZ concentration, exposure duration and on their interaction, leading to complex response patterns. The use of a standard statistical approach to analyze those data led to underestimation of VZ effects on reproduction, whereas effects could reliably be analyzed by mixed-effect models. L. stagnalis may be among the most sensitive invertebrate species to VZ, a 21-day reproduction test allowing the detection of deleterious effects at environmentally relevant concentrations of the fungicide. These results thus reinforce the relevance of L. stagnalis as a good candidate species for the development of guidelines devoted to the risk assessment of EDs.
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Oxygen evolution reaction (OER) is one of the most important reactions in the energy storage devices such as metal–air batteries and unitized regenerative fuel cells (URFCs). However, the kinetically sluggishness of OER and the high prices as well as the scarcity of the most active precious metal electrocatalysts are the major bottleneck in these devices. Developing low-cost non-precious metal catalysts with high activity and stability for OER is highly desirable. A facile, in situ template method combining the dodecyl benzene sulfuric acid sodium (SDBS) assisted hydrothermal process with subsequent high-temperature treatment was developed to prepare porous Co3O4 with improved surface area and hierarchical porous structure as precious catalysts alternative for oxygen evolution reaction (OER). Due to the unique structure, the as-prepared catalyst shows higher electrocatalytic activity than Co3O4 prepared by traditional thermal-decomposition method (noted as Co3O4-T) and commercial IrO2 catalyst for OER in 0.1 M KOH aqueous solution. Moreover, it displays improved stability than Co3O4-T. The results demonstrate a highly efficient, scalable, and low cost method for developing highly active and stable OER electrocatalysts in alkaline solutions. | battery |
The impact of carbon nanofibers as conductive additive on the electrochemical performance of a LiFePO4-based composite electrode for lithium battery is investigated here. We use a new method that allows discriminating between the electronic and the ionic wirings contributions to the polarization and the specific capacity at different discharge rates [C. Fongy, et al., J. Electrochem. Soc., 157 (2010) A885; C. Fongy, et al., J. Electrochem. Soc., 157 (2010) A1347]. Results show this conductive additive is not only beneficial in terms of electronic wiring but it also enables to reach better high rate performance by improving the ionic wiring as it decreases the tortuosity of the porosity within the composite electrode architecture. | battery |
An understanding of the pulse discharge behavior of commercial lithium coin cells in wireless sensing systems (WSs) is critical to prolonging the operating life and/or reducing the size of such systems. This paper is part of an effort to examine, model and optimize battery performance for sensor duty cycles consisting of multiple pulse discharges. The transient behavior of the cells during pulse discharge and the relaxation behavior following the pulse are both investigated with single-pulse experiments, and described with a simple mathematical model. In both cases, the voltage response is characterized by a region of rapid change, associated with ohmic and interfacial resistances, followed by a region of slower change. Solid phase diffusion in the cathode is the major contributor to the “slow” voltage change that occurs during and after a pulse. A simple analytical model, validated for this system, was found to accurately describe the time-dependent voltage and the corresponding non-uniform concentration distribution for the porous electrode. This transient study provides insight into and a description of the factors that influence and control battery behavior during pulsed cycling, and provides a tool to enable the next generation of battery-aware design of autonomous wireless sensing systems. | battery |
This work involves the use of a new type of composite anode system containing SnSb alloy and Li2.6Co0.4N for lithium secondary batteries based on solid polymer electrolytes. The composite electrode shows a high coulombic efficiency (close to 100% even in the first cycle) and a cycle capacity more than 500mAh/g. An addition of LiN(CF3SO2)2 salt into the electrode by direct powder-mixing will decrease its efficiency and capacity. The cycle performance of a cell, using the composite anode and LiNi0.8Co0.2O2 cathode, can be greatly enhanced by modifying the PEO-based polymer electrolyte with BaTiO3 as filler. | battery |
The current multimedia landscape is characterized by a significant heterogeneity in terms of coding and delivery formats, usage environments, and user preferences. The main contribution of this paper is a discussion of the design and functioning of a fully integrated platform for multimedia adaptation and delivery, called NinSuna. This platform is able to efficiently deal with the aforementioned heterogeneity in the present-day multimedia ecosystem, thanks to the use of format-agnostic adaptation engines (i.e., engines independent of the underlying coding format) and format-agnostic packaging engines (i.e., engines independent of the underlying delivery format). Moreover, NinSuna also provides a seamless integration between metadata standards and adaptation processes. Both our format-independent adaptation and packaging techniques rely on a model for multimedia bitstreams, describing the structural, semantic, and scalability properties of these multimedia streams. News sequences were used as a test case for our platform, enabling the user to select news fragments matching his/her specific interests and usage environment characteristics. | non-battery |
Little is known about the association between patient activation, health, service utilization, and cost among mental health (MH) patients. Patients aged 18 to 64 with schizophrenia (Sz, n = 43), bipolar disorder (BD, n = 59), or major depressive disorder (MDD, n = 34) completed the Patient Activation Measure for Mental Health (PAM-MH), the Colorado Symptom Index, demographic, socioeconomic, treatment, and social support questionnaire items. Average PAM-MH score indicated BD patients the most activated (66.6 ± 17.5), Sz (57.4 ± 10.4) less activated, and MDD the least activated (55.4 ± 14.6). The MDD cohort had the highest ($27,616 ± 26,229) and the BD had the lowest total annual healthcare cost ($18,312 ± 25,091). PAM-MH score was inversely correlated with healthcare costs and regression analysis showed a PAM-MH score × gender interaction. The strongest negative relationship between PAM and cost was for males. These analyses support the inverse association between PAM-MH and healthcare service utilization and cost.
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One of the most compelling, yet controversial new approaches to educational reform is Multiple Intelligences Theory, or MI. Recent advances in cognitive science, developmental psychology and neuroscience suggest that each person's intelligence is actually made up of autonomous faculties that can work individually or in concert with other faculties. Motivation has, on the other hand, been widely accepted by both teachers and researchers as one of the key factors that influence the rate and success of second/foreign language learning. According to Gardner (1985), there are two types of motivation: integrative and instrumental. An integratively motivated L2 learner shows interest in learning about the culture and the people of the target language, whereas an instrumentally motivated learner has more pragmatic considerations in his/her mind regarding L2 learning, such as obtaining a job or earning more money. Researchers (Arnold and Fonseca, 2004; Christison, 2005) argue that the base of intelligence and the type of motivation a learner possesses, affects the ways s/he favors certain materials and the ways s/he learns them. This study is an attempt to provide empirical evidence to the possible relation between the type and the base of intelligence and motivation, and learners’ satisfaction of EAP textbooks through the analysis of the data obtained from Student Textbook Evaluation Questionnaire, Multiple Intelligences Development Assessment Scales (MIDAS) Questionnaire, and Gardner's Motivation Test Battery (MTB). The results of the study showed that all the bases of intelligences could be found among the EAP students but logical-mathematical, spatial and interpersonal intelligences had the highest rates. The students were also instrumentally motivated and were somehow dissatisfied with their textbooks. Their dissatisfaction can be traced to the design, exercises and content of the textbook. | non-battery |
Information on mass and energy exchange at the soil surface under vegetation is a critical component of micrometeorological, climate, biogeochemical and hydrological models. Under sparse boreal and western conifer forests as much as 50% of incident solar energy reaches the soil surface. How this energy is partitioned into evaporating soil moisture, heating the air and soil remains a topic of scientific inquiry, as it is complicated by such factors as soil texture, litter, soil moisture, available energy, humidity deficits and turbulent mixing. Fluxes of mass and energy near the forest floor of a temperate ponderosa pine and a boreal jack pine stand were evaluated with eddy covariance measurements and a micrometeorological soil/plant/atmosphere exchange model. Field tests showed that the eddy covariance method is valid for studying the mean behavior of mass and energy exchange below forest canopies. On the other hand, large shade patches and sunflecks, along with the intermittent nature of atmospheric turbulence, cause run-to-run variability of mass and energy exchange measurements to be large. In general, latent heat flux densities are a non-linear function of available energy when the forest floor is dry. Latent heat flux densities (λE) are about one-quarter of available energy, when this energy is below 100Wm−2. Latent heat flux density (λE) peaks at about 35Wm−2 when available energy exceeds this threshold. A diagnosis of measurements with a canopy micrometeorological model indicates that the partitioning of solar energy into sensible, latent and soil heat flux is affected by atmospheric thermal stratification, surface wetness and the thickness of the litter layer. | non-battery |
The use of microalgae in the skin care market is already established although the scientific rationale for their benefit was not clearly defined. In this work, the biological activities of dermatologic interest of the water extract from the microalga Botryococcus braunii (BBWE) were evaluated by a battery of in vitro assays. At concentrations ranging from 0.1 to 0.001 % (w/v) BBWE promoted adipocytes differentiation by inhibiting hormone-sensitive lipase, thus promoting triglyceride accumulation in the cells. BBWE also induced gene expression of proteins involved in the maintenance of skin cells water balance such as aquaporin-3 (AQP3), filaggrin (FLG) and involucrin (INV). 0.1 % BBWE increased the gene expression of AQP3 of 2.6-folds, that of FLG and INV of 1.5- and 1.9-folds, respectively. Moreover, it induced the biosynthesis of collagen I and collagen III by 80 and 40 %, respectively, compared to the untreated control. BBWE antioxidant activity, evaluated by oxygen radical absorbance capacity (ORAC) assay, was of 43.5 μmol Trolox per gram of extract: a quite high value among those found for other microalgae extracts. BBWE inhibited the inducible nitric oxide synthase (iNOS) gene expression and the consequent nitrite oxide (NO) production under oxidative stress. At a concentration of 0.02 % BBWE reduced by 50 % the expression of iNOS and by about 75 % the NO production. Taken together, the results demonstrated that B. braunii water extract exerted an array of biological activities concurring with the skin health maintenance; therefore, it is a potential bioactive ingredient to be included in cosmetic products. | non-battery |
Graphene-based metals or metal oxides commonly show outstanding electrochemical performance due to superior properties of graphene. However, it still remains a challenge to directly grow low-valence oxides (e.g. tin monoxide) on graphene surface in term of the oxidizability of graphene oxide, which is normally adopted as a precursor for graphene. Herein, we report a novel strategy for preparation of tin and tin monoxide on graphene nanosheets by selectively using the reducing agent and the precipitant. Moreover, in contrast to free particles formed in solution, nanoscale tin or tin monoxide particles well-dispersed on graphene exhibited enhanced electro-chemical properties, including higher reversible capacities, better cycle performances, and higher rate capabilities. This facile one-step method may provide an attractive alternative approach for preparation of high-performance electrodes consisting of graphene and low-valence compounds. | battery |
The predicted dominance of electric vehicles and the need for grid-scale energy storage have heightened concerns that cobalt, a key constituent of lithium-ion batteries, could become a critical limiting factor. With limited terrestrial resources and over half the global production coming from politically challenging regions increasing risk, a shortage of cobalt could be experienced by the early 2020s. Fortunately, the oceans contain about 70 times more cobalt than on land and can be harvested sustainably with passive adsorption technologies; and a symbiotic system using existing offshore structures to harvest cobalt could enhance the economic feasibility of seawater cobalt harvesting. Our study finds that retrofitting just 76 unused oil platforms in the Gulf of Mexico could extract an average of 27.3% of the nation's 2017 cobalt consumption. New Offshore Opportunity for Underwater Cobalt Harvesting has the potential to reduce the cobalt supply pinch point in lithium-ion battery production. | battery |
The association of microneedles with electric pulses causing electroporation could result in an efficient and less painful delivery of drugs and DNA into the skin. Hollow conductive microneedles were used for (1) needle-free intradermal injection and (2) electric pulse application in order to achieve electric field in the superficial layers of the skin sufficient for electroporation. Microneedle array was used in combination with a vibratory inserter to disrupt the stratum corneum, thus piercing the skin. Effective injection of proteins into the skin was achieved, resulting in an immune response directed to the model antigen ovalbumin. However, when used both as microneedles to inject and as electrodes to apply the electric pulses, the setup showed several limitations for DNA electrotransfer. This could be due to the distribution of the electric field in the skin as shown by numerical calculations and/or the low dose of DNA injected. Further investigation of these parameters is needed in order to optimize minimally invasive DNA electrotransfer in the skin. | non-battery |
Ac impedance spectra of electrochemical systems are analyzed by considering adequate equivalent circuits, while the differentiation of responses for each elemental step is sometimes difficult. In this study, enlarged impedances were measured by lowering the temperature of a lithium ion battery (LIB) to make the separation of confusing responses easier. The impedance spectra obtained at the temperatures between −20 °C and 20 °C showed drastic change in sizes with shifting of the characteristic frequency. The analysis of impedance spectra using an equivalent circuit revealed changes in resistance of each component and shifting of the time constant for each elemental step. The frequency domain of impedance response of solid electrolyte interphase (SEI) was found to overlap with that of the inductive component of the outer electric lead at 20 °C in our study. The impedance measurement at the low temperatures is considered to be useful for the detection of the SEI and the accurate evaluation of LIB. | battery |
Epilepsy is characterized by impaired circuit function and a propensity for spontaneous seizures, but how plastic rearrangements within the epileptic focus trigger cortical dysfunction and hyperexcitability is only partly understood. Here we have examined alterations in sensory processing and the underlying biochemical and neuroanatomical changes in tetanus neurotoxin (TeNT)-induced focal epilepsy in mouse visual cortex. We documented persistent epileptiform electrographic discharges and upregulation of GABAergic markers at the completion of TeNT effects. We also found a significant remodeling of the dendritic arbors of pyramidal neurons, with increased dendritic length and branching, and overall reduction in spine density but significant preservation of mushroom, mature spines. Functionally, spontaneous neuronal discharge was increased, visual responses were less reliable, and electrophysiological and behavioural visual acuity was consistently impaired in TeNT-injected mice. These data demonstrate robust, long-term remodeling of both inhibitory and excitatory circuitry associated with specific disturbances of network function in neocortical epilepsy. | non-battery |
The capacity limits, local formation of Li2O2, passivation of active surfaces, and depletion of oxygen by mass transport characteristics in a composite cathode are modeled, numerically simulated, and experimentally evaluated for non-aqueous Li-O2 batteries employing composites of a solid polymer electrolyte and carbon particles as the cathode, Li metal as the anode, and an ion conductive oxide membrane as the separator. Although the theoretical maximum specific energy of the Li-O2 battery is known to be 3458 Wh kg−1 cathode, our simulation predicts a maximum specific energy of 1840 Wh kg−1 cathode with an optimized weight ratio of all essential components as well as cathode thickness. A specific energy of 1713 Wh kg−1 cathode is experimentally demonstrated in a cell with a composite cathode of poly(ethylene oxide) electrolyte and Printex carbon nanoparticles with 48% carbon volume and 30 μm thickness. The model also predicts that the incorporation of voids in the cathode can significantly improve the specific energy. | battery |
In this paper we evaluate the local seismic response for thirteen sites located in the municipalities of Arquata del Tronto and Montegallo, two areas which suffered heavy damage during the Mw 6.0 and Mw 5.4 earthquakes which struck Central Italy on August 24, 2016. The input dataset is made by ground motion recordings of 348 events occurred during the sequence. The spectral site response is estimated by the Generalized Inversion Technique and makes use of reference sites. The interpretation is further improved through the information provided by a reference-site independent method (i.e., the so called Receiver-Function Technique) and by the Horizontal-to-Vertical Spectral Ratios of ambient noise recordings. We also provide an independent estimate of the local amplification by comparing the Peak Ground Velocity and the Spectral Amplitudes observed at each site to the value estimated by well-established Ground Motion Prediction Equations for a rock-class site. The results obtained by the adopted methodologies are all highly consistent, and they emphasize the different seismic behavior of several sites at local scale. Thus, sites located on Quaternary deposits overlying the bedrock, such as Castro, Pretare, Spelonga, Pescara del Tronto, and Capodacqua feature some relevant amplifications in a medium (2–10 Hz) frequency range; two sites at Spelonga show amplifications also at low frequencies; three sites located on stiff formations, i.e. Uscerno, Balzo and Colle d’Arquata, respectively, feature either nearly neutral response or low amplification level. A probable topographic effect was identified at the rock site of Rocca di Arquata (MZ80). | non-battery |
Problem Statement Although some consider college student self-efficacy a unified construct with recommendations for measurement using questionnaires with total scores with “high reliability and validity”, separate analyses of subdomains may be warranted. Research Question Are there different findings at the subscale level in models of college student self-efficacy (course and social) that consider sex, language fluency and use, academic year, stress preventive resources, and depressive symptomology? Purpose of the Study This paper considers a contextual psycho-social model of college-student well-being among undergraduates at an English-language university in an ethno-culturally/linguistically diverse city in British Columbia, Canada. It differentiates between patterns of association of key variates from the model with two identified subdomains of college student self-efficacy, i.e., course and social subdomains. Research Method Participants were undergraduates at a mid-sized university. Participants completed a battery of questionnaires. Data on focal variables [college self-efficacy (course and social), background variables (sex, immigrant/citizenship generation, instructional language fluency and use, academic year), personality s, stress preventive resources, and depressive symptomology] were included in multivariate general linear model (GLM), hierarchical regression and correlational analyses. Findings Multivariate GLM analyses of the college self-efficacy subscales yielded omnibus effects (SSType I) for generation, language fluency and home use, academic year, select personality and stress preventive resources variates (ps<.05). Although there were key commonalities, the pattern of statistical significance differed by criterion variable in corresponding univariate GLM (SSType I) and hierarchical regression analyses. Conclusions Examination of the College Self-Efficacy Inventory and its subscales highlights that although overall scores may be of use, comparative analyses of findings at the subscale level should be considered. Importantly, it is not sufficient to compare/contrast ‘statistical significance’ profiles, statistical comparisons of corresponding correlations elucidates differential findings and assists developing nomothetic networks and targeted interventions to improve student outcomes. | non-battery |
Obsessive–compulsive symptoms (OCS) in psychotic disorders are associated with unfavorable outcomes, whether this extends to cognitive function remains unclear. We conducted meta-analyses on several cognitive domains to investigate overall group differences between patients with a psychotic disorder and co-occurring OCS (OCS +) and those without OCS (OCS−). We used meta-regression to assess possible confounding effects. No overall associations between OCS + and OCS− in any of the 17 investigated cognitive domains were found. We predominantly found large heterogeneity in effect size and direction among studies. Post-hoc analyses of processing speed tasks not purely based on reaction-time showed worse performance in the OCS + group with a small effect size (SMD = − 0.190; p = 0.029). Meta-regression revealed advanced age was significantly correlated with worse performance of the OCS + group in processing speed (R2 = 0.7), working memory (R2 = 0.11), cognitive inhibition (R2 = 0.59), and cognitive flexibility (R2 = 0.34). Patients fulfilling the criteria for an obsessive–compulsive disorder showed less impairment in cognitive inhibition compared to the OCS + group (R2 = 0.63). Overall, comorbid OCS were not associated with cognitive impairment. However, large heterogeneity between studies highlights the complex nature of factors influencing cognition in people with psychotic disorder and comorbid OCS and warrants further research into possible moderating factors.
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We have newly designed five kinds of polyvalent solute that have two to four quaternary ammonium functional groups in one cation. Their molecular structure is designed to be as compact as possible, with either two or three cationic groups on a linear molecular structure, or three or four cationic moieties on three strands in a star-shape. The prepared solutes have a bis(trifluoromethylsulfonyl)imide anion in common and a flexible molecular structure that can easily adsorb onto the electrode surface of an electric double layer capacitor (EDLC). Since a single polyvalent solute molecule can accumulate more electric charge by adsorption than can a monovalent solute, a high capacitance is possible even at a low solute concentration compared with conventional cells. We evaluated some electrochemical properties of these polyvalent solutes as an electrolyte and their EDLC performance, including initial capacitance, rate characteristics and cycle durability. All the polyvalent solutes had a potential window of 5 V or more, and in particular the divalent salt showed a capacitor performance equivalent to that of the monovalent salt even at half salt concentration in the electrolyte. On the other hand, the trivalent and tetravalent solutes had a lower charge utilization rate compared with a monovalent solute. | battery |
Abstract There is growing experience that supports the use of vagus nerve stimulator (VNS) therapy as an effective treatment for complex epilepsy. The number of clinical conditions for which VNS has been tried and reported anecdotally to help continues to grow. As such, VNS represents the most widely clinically utilized form of neuromodulation therapy in clinical practice today. This chapter reviews the evolution of understanding of the rationale for VNS, summarizes outcomes and indications reported to date, and discusses surgical considerations in the surgical placement of a VNS device. | non-battery |
Globally, electrical and electronic equipment (EEE) is now a part of daily life. When this equipment becomes waste electrical and electronic equipment (WEEE or E-waste), however, it needs to be properly processed, for use as a source of materials for future production and renewable energy, and to minimize both the exploitation of raw materials and the deleterious effects on both the environment and human health. A large quantity of e-waste is generated in both India and China, and both countries still suffer from an entrenched informal e-waste processing sector. Consequently, valuable materials in e-waste are disposed in open land, rather than being properly extracted for reuse and recycling. In this article we note that the major portion of e-waste in China and India is collected by the informal sector and treated with primitive methods. Additionally, illegal shifting agents also play a role by mislabeling e-waste and exporting them to developing countries. This article proposes that: the implementation of e-waste management laws and policies for proper e-waste collection, treatment and recycling, better educate consumers on the dangers of e-waste contamination, restrict the illegal movement of e-waste across borders, and support the development of a formal, regulated e-waste processing industry by funding incentive programs constructing recycling infrastructure. These measures should increase the recycling capacity and decrease the amount of WEEE contaminating the environment and endangering human health. | battery |
In children and adolescents, 1 mA transcranial direct current stimulation (tDCS) may cause “paradoxical” effects compared with adults: both 1 mA anodal and cathodal tDCS increase amplitude of the motor evoked potential (MEP) as revealed by a single pulse transcranial magnetic stimulation (TMS) of the motor cortex. Here, EEG based evoked potentials induced by a single pulse TMS, particularly the N100 component as marker of motor cortex inhibition, were investigated in order to explain effects of tDCS on the developing brain. In nineteen children and adolescents (11–16 years old), 1 mA anodal, cathodal, or sham tDCS was applied over the left primary motor cortex for 10 min. The TMS-evoked N100 was measured by 64-channel EEG before and immediately after stimulation as well as every 10 min after tDCS for one hour. 1 mA Cathodal stimulation suppressed the N100 amplitude compared with sham stimulation. In contrast, anodal tDCS did not modify the N100 amplitude. It seems likely that the increase of the motor cortex activity under cathodal tDCS in children and adolescents as shown in previous studies can be attributed to a reduce inhibition. Based on TMS evoked N100, the study provides an insight into neuromodulatory effects of tDCS on the developing brain. | non-battery |
Improving current in vitro genotoxicity tests is an ongoing task for genetic toxicologists. Further, the question on how to deal with positive in vitro results that are demonstrated to not predict genotoxicity or carcinogenicity potential in rodents or humans is a challenge. These two aspects were addressed at the 5th International Workshop on Genotoxicity Testing (IWGT) held in Basel, Switzerland, on August 17–19, 2009. The objectives of the working group (WG) were to make recommendations on the use of cell types or lines, if possible, and to provide evaluations of promising new approaches. Results obtained in rodent cell lines with impaired p53 function (L5178Y, V79, CHL and CHO cells) and human p53-competent cells (peripheral blood lymphocytes, TK6 and HepG2 cells) suggest that a reduction in the percentage of non-relevant positive results for carcinogenicity prediction can be achieved by careful selection of cells used without decreasing the sensitivity of the assays. Therefore, the WG suggested using p53- competent – preferably human – cells in in vitro micronucleus or chromosomal aberration tests. The use of the hepatoma cell line HepaRG for genotoxicity testing was considered promising since these cells possess better phase I and II metabolizing potential compared to cell lines commonly used in this area and may overcome the need for the addition of S9. For dermally applied compounds, the WG agreed that in vitro reconstructed skin models, once validated, will be useful to follow up on positive results from standard in vitro assays as they resemble the properties of human skin (barrier function, metabolism). While the reconstructed skin micronucleus assay has been shown to be further advanced, there was also consensus that the Comet assay should be further evaluated due to its independence from cell proliferation and coverage of a wider spectrum of DNA damage. | non-battery |
To effectively avoid the “dead volume” and improve the utilization ratio of the electrode material, a novel longan-like hybrid structure has been designed and fabricated by controlled growth of Ni(OH)2 nanosheets on the surface of yolk–shell PPy nanospheres at a mild reaction temperature. The strategy takes full advantages of the hollow structure and further reduces the charge transport distance, leading to high conductivity and energy storage capacity of longan-like hybrid structures. Furthermore, the assembled asymmetric supercapacitors (ASCs) exhibits a high retention ratio of 91.5% for capacitance after 6000 continuous cycles and an impressive energy density of 34 W h kg−1 at 755 W kg−1. Remarkably, two devices in series have a higher cell-voltage output of 3.0 V compared to a single device. This work will supply a new hollow nanostructure design strategy to enhance the electrochemical performance of electrode materials. | battery |
Carbon coating of silicon powder was studied as a means of preparation of silicon-based anode material for lithium ion batteries. Carbon-coated silicon has been investigated at various cycling modes vs. lithium metal. Ex situ X-ray data suggest that there is irreversible reduction of crystallinity of the silicon content. Since carbon layer preserving the integrity of the particle, the reversibility of the structural changes in the amorphous state Li–Si alloy provides the reversible capacity. The progressively decreased Coulomb efficiency with cycling indicates that more and more lithium ions are trapped in some form of Li–Si alloy and become unavailable for extraction. This is the main factor for the capacity fading during cycling. Qualitative studies of the impedance spectra of the electrode material at the first cycle for the fresh anode and at the last cycle after the anode capacity faded considerably and provide further support for this model of fading mechanism. | battery |
Single particle measurement is a known characterization method for electrode materials. In a conventional single particle measurement, highly advanced techniques are necessary to electrically bring a microelectrode into contact with a single-particulate active material while observing with an optical microscope. Our measurement method doesn't require a high level of skill by using a “particle-current collector integrated microelectrode”, in which the single active material particle was directly-contacted on the tip of the microelectrode by platinum deposition. In this study, the intrinsic properties of a conventional Li4Ti5O12 (LTO) single particle were investigated by using the integrated microelectrode without any binder and carbon additives. Cyclic voltammograms and charge-discharge profiles at various temperatures between 10 and 40°C revealed that Li+ extraction (discharge) was faster than Li+ insertion (charge) because of the difference in Li+ diffusion into the single LTO particle, thereby exhibiting remarkable discharge capacity retention (>80%) even at 1000C and 10°C. Cycle performance at charge-discharge rate of 30C showed excellent reversibility, in which capacity retention and Coulombic efficiency were estimated to be 96.4% and 99.97%, respectively, even after 5000cycles. | battery |
Electrodeposition and dissolution of zinc in methanesulfonic acid were studied as the negative electrode reactions in a hybrid redox flow battery. Cyclic voltammetry at a rotating disk electrode was used to characterize the electrochemistry and the effect of process conditions on the deposition and dissolution rate of zinc in aqueous methanesulfonic acid. At a sufficiently high current density, the deposition process became a mass transport controlled reaction. The diffusion coefficient of Zn2+ ions was 7.5×10−6 cm2 s−1. The performance of the zinc negative electrode in a parallel plate flow cell was also studied as a function of Zn2+ ion concentration, methanesulfonic acid concentration, current density, electrolyte flow rate, operating temperature and the addition of electrolytic additives, including potassium sodium tartarate, tetrabutylammonium hydroxide, and indium oxide. The current-, voltage- and energy efficiencies of the zinc-half cell reaction and the morphologies of the zinc deposits are also discussed. The energy efficiency improved from 62% in the absence of additives to 73% upon the addition of 2×10−3 moldm−3 of indium oxide as a hydrogen suppressant. In aqueous methanesulfonic acid with or without additives, there was no significant dendrite formation after zinc electrodeposition for 4h at 50mAcm−2. | battery |
In order to measure the electrochemical characteristics of both electrodes inside Li-ion batteries, micro-reference electrodes (μREF) turned out to be very useful. However, measuring the electrochemical impedance with respect to μREF can lead to severe measurement artefacts, making a detailed analysis of the impedance spectra complicated. In the present work a new method is developed in which high-frequency measurement artefacts can be compensated. A theoretical analysis, using equivalent circuit models of the measurement setups, shows that if two different impedance measurements are averaged, the impedance contributions from the measurement leads can be completely eliminated. The theoretical analysis is validated using Li-ion batteries with seven integrated μREF, having all different impedances. The measurement results show that artefacts are dominating for high-impedance μREF in the high frequency range. However, these artefacts can be fully compensated by averaging two separate impedance measurements, as predicted by theory. This easily makes it possible to perform artefact-free impedance measurements, even at high frequencies. | battery |
Resumen Objetivo Conocer en base a los estudios publicados más recientes, la efectividad clínica del ejercicio físico como tratamiento en la enfermedad de Alzheimer y analizar la calidad metodológica de los artículos. Búsqueda y selección de estudios Se identificaron 111 publicaciones mediante búsqueda electrónica y manual, de los cuales se seleccionaron 16 en base a los criterios de inclusión: ensayos controlados y estudios experimentales con pre y post-test publicados a partir de enero de 2005, cuyo número de muestra sea ≥ 5 en cada grupo y a los que se les haya aplicado ejercicio físico como tratamiento para la enfermedad. Resultados y conclusiones La calidad metodológica media de los estudios incluidos fue de 5 puntos (de 10 posibles). Como resultado del tratamiento mejoraron de forma significativa la función cognitiva, el equilibrio, la depresión y la calidad de vida. Son necesarios estudios con una muestra de intervención más homogénea para determinar la efectividad del ejercicio físico en el tratamiento de la enfermedad de Alzheimer. | non-battery |
Since the birth of lithium ion battery in the end of 1980s and early 1990s many kinds of anode materials have been studied. Nevertheless, graphitic carbon is still the only commercially available product. As a result, modification of carbonaceous anode materials has been a research focus. In this paper, latest progress on carbon anode materials for lithium ion batteries is briefly reviewed including research on mild oxidation of graphite, formation of composites with metals and metal oxides, coating by polymers and other kinds of carbons, and carbon nanotubes. These modifications result in great advances; novel kinds of carbon anodes will come in the near future, which will propel the development of lithium ion batteries. | battery |
Static 7Li and 1H NMR experiments were performed between 150 and 400 K. The contributions of both 7Li–7Li and 7Li–1H dipolar interactions to the magnetic second moment were determined in the rigid-lattice regime (T<220 K). Calculated magnetic second moments for different PEO conformations, considering both intra- and inter-molecular interactions, indicate that the polymer in this nanocomposite is compatible with CC bonds predominately in gauche conformations and the oxygen atoms defining tetrahedral sites hosting the lithium ions. The model adequately satisfies the geometric restrictions determined by the structure and the stoichiometry of the product. Furthermore, the temperature dependence of the 7Li linewidth and the 7Li and 1H spin-lattice relaxations for the nanocomposite and two reference compounds, (PEO)8LiClO4 and Li0.22MoS2, provided information about the effects of PEO intercalation on the polymer and Li+ dynamics and conformation, indicating that Li+ mobility is coupled to polymer motion, the polymer motion is restricted by the intercalation process, and the chain conformation inside the interlayer space is in the sequence TGGT GG TGG. | battery |
Understanding the rate of heat generation in a Li-ion cell is critical for safety and performance of Li-ion cells and systems. Cell performance, cycle life, and system safety all depend on temperature distribution in the cell, which, in turn, depends on heat generation rate within the cell and on heat removal rate at the cell surface. Despite the existence of a number of theoretical models to predict heat generation rate, there is not much literature on experimental measurement at high C-rates. This paper reports measurement of heat generation rate from a Li-ion cell at high discharge rates, up to 9.6C, using measurements of cell temperature and surface heat flux. As opposed to calorimetry-based approaches, this method can be applied in situ to yield measurements of heat generation rate in laboratory or field use provided that at least one a priori test is performed to measure the temperature gradient within a cell in the same ambient condition. This method is based on simultaneous determination of heat stored and heat lost from the cell through heat flux and temperature measurements. A novel method is established for measurement of the internal temperature of the cell. Heat generation measurements are shown to agree with well-established theoretical models. The effect of actively cooling the cell is briefly discussed. | battery |
The new systemic conditions following the change of the political regime in Poland in 1989 have created growth opportunities for towns. The conditions make it necessary for them to compete for investment and other growth factors, which can play an important part in their transformation. The large Polish cities that have made the most of the new socio-economic situation also include Poznań. The article presents key problems and achievements of the city’s transformation as moulded by the historical past, the rebirth of local government (the actual manager of an area), demographic changes, diversification of the economic structure, foreign investment, a change in the residential housing model, the development of the service sector, etc. The growth of the city and its suburban zone has also been influenced by post-modern tendencies in the development of contemporary towns, including the process of metropolitanisation. All those factors have combined to make Poznań an exceptional city among other regional centres in Poland, one that has clearly gained during the transformation. | non-battery |
A novel 2Li3V2(PO4)3·LiV3O8 composite with short rod and thin plate shapes is synthesized through sol–gel method followed by hydrothermal and solid–state reaction. LiV3O8 is used as an additive to improve the capacity of Li3V2(PO4)3. In the composite cathode, active impurity phase Li0.3V2O5 is also present, which has little impact on the whole electrochemical properties. The 2Li3V2(PO4)3·LiV3O8 composite delivers a high initial capacity of 162.8 mAh g−1 at a current density of 100 mA g−1 in the voltage range of 2.0–4.3 V. Furthermore, the composite with high crystallinity also shows high electrochemical reversibility and good rate capability. The diffusion coefficient of Li ions in the composite is in the range of 10−11–10−9 cm2 s−1 obtained from galvanostatic intermittent titration technique. | battery |
The titanium dioxide nanotube array (TiO2-NTA) is prepared by a two-step anodic oxidation method and annealed at 450 ∘C subsequently. The Al-inserted TiO2-NTA is prepared by polarizing the TiO2-NTAs electrode at 0.4mA for 2min in 1mol/L AlCl3. The results show that the Al-inserted sample still remains pure anatase TiO2 phase (by XRD) and keeps intact nanotube array structure (by FE-SEM). The X-ray photoelectron spectroscopy (XPS) analysis indicates that the insertion of Al3+ into TiO2-NTAs facilitates in the reduction of Ti4+ to Ti3+. Electrochemical investigation on the Al3+ insertion process reveals that presence of Cl− ions plays vital role for the effective insertion and de-insertion of Al3+ into/from the TiO2-NTA. | battery |
Experimental investigation and relevant analysis on a solar cell driven, thermoelectric refrigerator has been conducted. To make the device portable, daytime use and nighttime use of the refrigerator are treated in different ways. Solar cells are applied to power the refrigerator in the day. Storage battery, assisted by an a.c. rectifier, is used to provide electric energy in the night and in cloudy or rainy days. Experiment results demonstrate that the unit can maintain the temperature in the refrigerator at 5–10 °C, and have a COP about 0.3. It is expected that the refrigerator would be potential for cold storage of vaccine, foodstuffs and drink in remote area, or outdoor applications where electric power supply is absent. | battery |
Although manganese oxide (MnO2) can be incorporated with vertically aligned carbon nanotubes (VACNTs) to improve supercapacitor performance potentially, one of the hurdles that hampers this embodiment is a difficulty of coating MnO2 on VACNTs homogeneously. As a way of overcoming this hurdle, we present here a facile method of pulsed current electrodeposition that turns out to exceed conventional methods in coating quality. Such improvement leads to a clear enhancement in gravimetric specific capacitance, reaching a state-of-the-art value of 243.3 F/g at a high scanning rate of 100 mV/s. In the course of this characterization, diffusion hindrance through a MnO2 layer clogging over VACNTs is found out to limit the device performance at high mass loading. An empirical relationship is proposed to explain such phenomenon and demonstrates good application in various conditions. The optimized VACNTs/MnO2 electrode also reveals outstanding high-rate performances. | battery |
Alexithymia is a personality construct characterized by a cognitive and an affective deficit in recognizing and communicating emotional states. The present research investigated the relations between alexithymia, well-being, and romantic relationships in 437 undergraduates. High levels of alexithymia were found in 18.5 % of the sample and were associated with high levels of depression and negative affect, and low levels of life satisfaction, happiness and positive affect. Alexithymia was also negatively correlated with the quality of romantic relationships and with commitment, romance, trust, satisfaction and love in romantic relationships. The relation between alexithymia and subjective well-being was mediated in part by the poor quality of their romantic relationships. Alexithymia accounted for significant portions of the variance in depression (19.0 %), negative affect (17.4 %), life satisfaction (14.4 %), happiness (20.4–29.8 %) and positive affect (20.1 %). However, alexithymia failed to account for variance in either negative or positive well-being above and beyond the variance accounted for by the Big Five personality traits. These results are consistent with the position that alexithymia can be thought of as a constellation of extreme levels of normative personality traits. | non-battery |
In situ transmission FTIR spectra are measured during the electrochemical insertion of lithium into phospho-olivine FePO4. The spectroelectrochemical cell consists of a composite FePO4 cathode, a lithium metal anode, and an electrolyte of 1M LiPF6 in a 1:1 mixture of ethylene carbonate and diethyl carbonate (EC–DEC). Bands belonging to the electrolyte and cathode are identified in the infrared spectra of the in situ cells. The antisymmetric PO4 3− bending vibrations (ν4) are used to monitor Li+ insertion into FePO4. Discharging produces spectral changes that are consistent with the formation of phospho-olivine LiFePO4, yet the electrolyte bands are not affected by the discharging process. The in situ infrared experiments confirm the two-phase mechanism for lithium insertion into FePO4. Moreover, the experiments demonstrate the ability to collect in situ transmission FTIR spectra of functioning electrode materials in lithium batteries. Unfortunately, lithium plating occurs on the optical window when the Li//FePO4 half-cells are charged. The use of an intercalation anode such as graphite could alleviate this problem; however, this avenue of research is not explored in this study. | battery |
Background and purpose Many patients with Parkinson's disease (PD) experience sleep-related symptoms. Studies in other populations indicate that melatonin can increase sleep efficiency, decrease nighttime activity, and shorten sleep latency, but there has been little research on the use of melatonin in PD. The purpose of this study was to compare the effects of two doses of melatonin to placebo on sleep, daytime sleepiness, and level of function in patients with PD who complained of sleep disturbances. Patients and methods A multi-site double-blind placebo-controlled cross-over trial was employed; 40 subjects completed the 10-week protocol. There was a 2-week screening period, 2-week treatment periods, and 1-week washouts between treatments. Nocturnal sleep was assessed by actigraphy and diaries, whereas daytime sleepiness and function were assessed by the Epworth Sleepiness Scale (ESS), Stanford Sleepiness Scale (SSS), and General Sleep Disturbance Scale (GSDS). Results Repeated measures analysis of variance revealed a significant improvement in total nighttime sleep time during the 50mg melatonin treatment compared to placebo. There was significant improvement in subjective sleep disturbance, sleep quantity, and daytime sleepiness during the 5mg melatonin treatment compared to placebo as assessed by the GSDS. Conclusions Although we found a statistically significant improvement in actigraphically measured total sleep time on 50mg melatonin compared to 5mg or placebo, this small improvement (10min) may not be clinically significant. However, the significant improvement found in subjective sleep disturbance suggests that these modest effects may be clinically relevant in this patient population. | non-battery |
Drawing from the dual process model of morality and life history theory, the present research examined the role of cognitive and emotional processes as bridges between basic environmental challenges (i.e., unpredictability and competition) and other-centered moral orientation (i.e., prioritizing the welfare of others). In two survey studies, cognitive and emotional processes represented by future-oriented planning and emotional attachment, respectively (Study 1, N = 405), or by perspective taking and empathic concern, respectively (Study 2, N = 424), positively predicted other-centeredness in prosocial moral reasoning (Study 1) and moral judgment dilemmas based on rationality or intuition (Study 2). Cognitive processes were more closely related to rational aspects of other-centeredness, whereas the emotional processes were more closely related to the intuitive aspects of other-centeredness (Study 2). Finally, the cognitive and emotional processes also mediated negative effects of unpredictability (i.e., negative life events and childhood financial insecurity), as well as positive effects of individual-level, contest competition (i.e., educational and occupational competition) on other-centeredness. Overall, these findings support the view that cognitive and emotional processes do not necessarily contradict each other. Rather, they might work in concert to promote other-centeredness in various circumstances and might be attributed to humans’ developmental flexibility in the face of environmental challenges.
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Audit offices in the US exhibit a wide variation in the number of industries they service. Strategic management theory suggests that diversification can affect the quality of output, depending on the nature and circumstances of diversification. This paper examines the effect of diversification at the audit office level on audit quality. Five proxies of audit quality are examined, mainly, absolute discretionary accruals, propensity to meet-or-beat earnings expectations by a cent, propensity to restate financial statements, propensity to receive a comment letter after an SEC review and propensity to issue a going concern opinion. Results suggest that diversification has detrimental effects on audit quality. On the other hand, when the diversification is part of the audit firm level strategy, the detrimental effects on audit quality are dampened. Moreover, when the diversification at the office level is part of a revenue expansion strategy, the audit quality is adversely affected. However, there is no detrimental effect on the audit quality when revenue expansion is not the objective. Also, diversification across dissimilar industries leads to more adverse effect on audit quality than diversification to similar industries. Results also suggest that when the audit office is located in a market with more (less) diversified client base, the adverse effects of diversification on audit quality are weaker (stronger). Finally, the offices of big-4 audit firms handle diversification better with less adverse effect on audit quality. The findings are important since they identify additional factors that explain audit quality at the audit office level. | non-battery |
In this paper, a novel impedance spectroscopy was used to describe the thermal behaviors of Ni-MH batteries. The impedance functions were derived similarly to electric impedance functions. The square of current was treated as a current equivalent and heat-flow as a voltage equivalent. The impedance spectra of batteries during charge showed that the combination of hydrogen and oxygen increased rapidly when charge rate was higher than 0.5C. Thermal runaway might happen when battery was charged at temperature above 348K even at a low charge rate. The cycling test showed that the charge efficiency of battery was the highest after cycling at high-rate for 10–100 cycles and decreased after more cycles. Different batteries showed different thermal behaviors which may be caused by the different structures of batteries. | battery |
Amorphous MgNi material has been synthesized by mechanical alloying and sieved into three particle size fractions: >75, 20–75, and <20μm. The influence of the MgNi particle size on its electrochemical behavior as negative electrode for Ni–metal hydride (MH) batteries has been investigated. The initial discharge capacity is higher as the MgNi particle size increases, i.e. the initial discharge capacity of particles larger than 75μm is 439mAh/g compared to 396 and 328mAh/g for 20–75 and <20μm particles, respectively. In addition, the cycle life of the MgNi electrode is improved by increasing the particle size. That is, the >75μm particles electrode retains 41% of its initial capacity after 15 cycles compared to 35 and 23% for 20–75μm and <20μm particles electrodes, respectively. The rate dischargeability is also improved by increasing the MgNi particle size. For example, at 400mA/g, the >75μm particles electrode delivers 33% of its capacity measured at 20mA/g compared to 25 and 19% for 20–75μm and <20μm powders, respectively. These results can be explained by the lower specific surface area of the electrode constituted of large particles which limits the formation of Mg(OH)2 resulting from the MgNi oxidation by the electrolyte. Moreover, on the basis of the evolution of the cycling discharge capacities with increasing charge input for the different powder fractions, it appears that the electrode resistance to pulverization is improved by increasing the MgNi particle size. | battery |
Although the outcome of total knee replacement (TKR) is favorable, surgery alone fails to resolve the functional limitations and physical inactivity that existed prior to surgery. Exercise is likely the only intervention capable of improving these persistent limitations, but exercises have to be performed with intensity sufficient to promote significant changes, at levels that cannot be tolerated until later stages post TKR. The current evidence is limited regarding the effectiveness of exercise at a later stage post TKR. To that end, this study aims to compare the outcomes of physical function and physical activity between 3 treatment groups: clinic-based individual outpatient rehabilitative exercise during 12 weeks, community-based group exercise classes during 12 weeks, and usual medical care (wait-listed control group). The secondary aim is to identify baseline predictors of functional recovery for the exercise groups. | non-battery |
Polymer electrolytes consisting of poly(ethylene oxide) (PEO) and lithium salts, such as LiCF3SO3 and LiBF4 are prepared by the ball-milling method. This is performed at various times (2, 4, 8, 12h) with ball:sample ratio of 400:1. The electrochemical and thermal characteristics of the electrolytes are evaluated. The structure and morphology of PEO–LiX polymer electrolyte is changed to amorphous and smaller spherulite texture by ball milling. The ionic conductivity of the PEO–LiX polymer electrolytes increases by about one order of magnitude than that of electrolytes prepared without ball milling. Also, the ball milled electrolytes have remarkably higher ionic conductivity at low temperature. Maximum ionic conductivity is found for the PEO–LiX prepared by ball milling for 12h, viz. 2.52×10−4 Scm−1 for LiCF3SO3 and 4.99×10−4 Scm−1 for LiBF4 at 90°C. The first discharge capacity of Li/S cells increases with increasing ball milling time. (PEO)10LiCF3SO3 polymer electrolyte prepared by ball milling show the typical two plateau discharge curves in a Li/S battery. The upper voltage plateau for the polymer electrolyte containing LiBF4 differs markedly from the typical shape. | battery |
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