batterydata/paper-abstracts huggingface dataset:
Copper sulfide nanoflower/reduced graphene oxide (CuS/rGO) composite is synthesized using Cu(NO3)2, thiourea (Tu) and graphene oxide (GO) powers as the precursor by an ultrafast microwave-assisted hydrothermal method. The electrochemical performances of CuS/rGO composite as anode material of Lithium ion batteries (LIBs) are studied both in ether-based (LiTFSI in DOL/DME) and carbonate-based electrolytes (LiPF6 in EC/DMC). The results reveal that CuS/rGO composite exhibits excellent electrochemical Li-storage properties. The reversible capacity of 422mAhg−1 and 390mAhg−1 at a current density of 100mAg−1 after 70 cycles is obtained in both electrolytes, respectively. Even after 200 charge-discharge cycles at 500mAg−1 in ether-based electrolyte, the composite delivers a good discharge capacity of 390mAhg−1 with high capacity retention ratio of 96.7%. The good electrochemical performances of CuS/rGO can be attributed to the synergistic effect of the CuS nanoflower and rGO. Briefly, the introduction of rGO can improve the electronic conductivity of the composite, effectively immobilize the CuS and inhibit the dissolution of the polysulfide intermediates generated during the charge-discharge process.
A new oxysulfide spinel, LiAl0.15Mn1.85O3.97S0.03 with well-developed octahedral structure was synthesized by a sol–gel method using glycolic acid as a chelating agent. The electrochemical performance of the oxysulfide was studied compared with those of S-doped spinel, LiMn2O3.98S0.02 and Al-doped spinel LiAl0.24Mn1.76O4. The LiAl0.15Mn1.85O3.97S0.03 electrode shows no capacity loss in the 3 and 4 V region. The origin of no capacity loss of the electrode was investigated by XRD and HRTEM. The substitution of S for O in LiMn2O4 stabilized the structural integrity of the spinel host, which in turn increased electrochemical cyclability.
Resumen Objetivo Verificar si el deterioro cognitivo puede afectar a la puntuación total obtenida en el test Freezing of Gait score (FOG-score) en pacientes con la enfermedad de Parkinson (EP). Material y método Se llevó a cabo un estudio no experimental, seccional correlacional en 34 participantes, con EP leve o moderada. Los participantes ejecutaron el test de FOG-score y las siguientes pruebas de evaluación cognitiva: Mini examen cognoscitivo (MEC), Frontal Assessment Battery (FAB) y Fuld Object Memory Evaluation (FOME). La función motora fue medida mediante el apartado iii de la Unified Parkinson's Disease Rating Scale (UPDRS), referente a los aspectos motores. Resultados Se halló una correlación significativa negativa entre la puntuación total del FOG y la función cognitiva global (Mini examen cognoscitivo) (r=0,68; p<0,001); los parámetros relacionados con la memoria (FOME) (r=0,64; p<0,001) y las funciones ejecutivas (FAB) (r=0,57; p<0,001). Las puntuaciones de los aspectos motores mantienen una menor relación con los parámetros del FOG-score (r=0,35; p>0,005). Conclusiones Los resultados de este estudio sugieren que el deterioro cognitivo puede afectar fuertemente en el desarrollo de las tareas del test FOG-score. Esto implica la necesidad de ajustar el punto de corte en la evaluación de personas con EP que padecen disfunción cognitiva, lo que evitaría que el examinador sobreestimase la existencia y recurrencia de episodios de congelación en esta población.
The electrochemical performance and storage properties of Ni-rich cathode materials (LiNi0.8Co0.15Al0.05O2) are improved via fast cooling methods (fast and ultrafast cooling). X-ray diffraction (XRD) results demonstrate that the interslab thickness of a fast-cooled sample is larger, and the degree of cation mixing is relatively lower, than in an untreated sample. X-ray photoelectron spectroscopy (XPS) confirms that the content of Ni3+ on the surface of a fast-cooling treated sample is lower, while the average valence state of Ni obtained via titration is higher, than in the untreated sample, indicating the existence of a surface layer with less Ni3+ for as-treated samples. Electrochemical characterizations confirm that as-treated samples display better cycling stability at 25°C and 55°C, as well as better rate capability, consistent with the XRD results. Fourier-transformed infrared spectrum (FTIR), XRD and electrochemical analysis confirm that the storage properties of fast-cooled samples are also enhanced. These results suggest that fast-cooled LiNi0.8Co0.15Al0.05O2 with less Ni3+ at the surface and larger interslab thickness in the bulk is a promising cathode material for high performance lithium ion batteries.
Li-rich layered oxide cathode Li1.26Fe0.22Mn0.52O2 is synthesized via a low temperature molten salt method, and the carbon modified samples are fabricated through coating sucrose on the precursors with different sucrose ratios. The crystal structure and morphology of the pristine and the carbon modified samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The crystal structure appears as a hexagonal α-NaFeO2 layered structure (space group: R 3 ¯ m ) and is kept after carbon modified. The carbon element distributes uniformly on the surface of the modified samples verified by Energy Dispersive Spectrometer (EDS). The electrochemical performance of the Li1.26Fe0.22Mn0.52O2 Li-rich cathode materials is greatly improved after carbon modification. The cycling stability of the carbon modified samples is also highly improved compared with the pristine. Particularly the rate performance is enhanced by the appropriate coating content of sucrose (1:6), the discharge capacities are 160mAh/g, 133mAh/g and 78mAh/g at 2C, 3C and 5C rate respectively. They also have 83.4%, 82.5% and 83.4% capacity retention after 50cycles at 2C, 3C and 5C respectively. Electrochemical Impedance Spectroscopy (EIS) results demonstrate that the charge transfer resistance of the carbon modified sample decreases obviously. It is suggested that the carbon modification could minimize the cell polarization and increase the electronic conductivity of the Li-rich cathode materials. Additionally, the annealing process of sucrose coating may offer much higher local temperature to improve the crystallization and volatile the excess Li source to suppress Li2CO3 impurity formation verified by the result of XPS.
Objective Mental fatigue, a poorly understood symptom of sports-related concussion, ideally requires assessment across multiple modalities. Our study aimed to examine mental fatigue effects among 10 neurologically normal, athletically active students undergoing typical concussion testing. It is our intention to ultimately address the question whether fatigue effects due to mild traumatic brain injury (mTBI) may become confounded with fatigue effects due to testing effort. Methods Fourteen athletically active and neurologically normal volunteers were initially recruited from Penn State University. Self-reported fatigue, neuropsychological performance, and electroencephalographic (EEG) activity were measured throughout the whole testing duration. EEG measures in frequency domain (e.g., relative power of theta, alpha, and beta bands) were examined over the course of neuropsychological (NP) test administration. Results Predicted fatigue effects over the course of testing included: (a) increased self-reported fatigue; (b) increased errors on the Stroop Interference Test; (c) significantly increased relative power of theta activity during the Stroop Interference Test in frontal–central and parietal regions; and (d) migration of alpha activation from the occipital to anterior (left parietal and pre-central) regions during the Stroop Interference task administered at the beginning compared with the end of testing. Conclusions Results supported predictions related to subjective fatigue and cognitive performance and offered partial support for predictions related to EEG activation patterns over the course of administering the NP testing. Significance Neurologically intact and athletically active college students demonstrate effects related to fatigue after undergoing a typical sports concussion assessment battery, including an increase in subjectively experienced fatigue, a decrease in cognitive task performance accuracy and associated modulations in EEG activity. This finding should be considered by clinical practitioners while evaluating the symptoms of concussion and making a decision regarding the return-to-sport participation.
The harsh climate in Sudan presents unique challenges in meeting growing demands for power and water. The international demand of water increases compared to the available water resources, due to recent development water resources for different uses. In many areas especially in Red Sea areas, there is serious a shortage of potable water. These areas are enjoyed with a high intensity of solar energy. The move towards a de-carbonised world, driven partly by climate science and partly by the business opportunities it offers, will need the promotion of environmentally friendly alternatives, if an acceptable stabilisation level of atmospheric carbon dioxide is to be achieved. This requires the harnessing and use of natural resources that produce no air pollution or greenhouse gases and provides comfortable coexistence of human, livestock, and plants. This study reviews the energy-using technologies based on natural resources, which are available to and applicable in the farming industry. Among these are greenhouses, which are necessary for the growth of some plants (i.e., vegetables, flowers, etc.), in severe climates. Globally, buildings are responsible for approximately 40% of the total world annual energy consumption. Most of this energy is for the provision of lighting, heating, cooling, and air conditioning. Increasing awareness of the environmental impact of CO2 and NO x emissions and CFCs triggered a renewed interest in environmentally friendly cooling, and heating technologies. Under the 1997 Montreal Protocol, governments agreed to phase out chemicals used as refrigerants that have the potential to destroy stratospheric ozone. It was therefore considered desirable to reduce energy consumption and decrease the rate of depletion of world energy reserves and pollution of the environment.
Iron fluoride cathode for lithium batteries intrigues researchers for decades due to high capacity and low cost, but suffers from poor electronic and ionic conductivity. Hierarchical micro/nano construction with preferred orientation growth can shorten ion diffusion pathway and facilitate electron transportation without inducing side reactions. Here, FeF3·0.33H2O hierarchical microspheres self-assembled by octagonal single crystal slices are prepared. Benefiting from the artful structure, SAED and XRD characterizations confirm that the octagonal single crystal slices provides more lithium ions intercalation positions (4c sites). Electrochemical tests demonstrate that the well designed FeF3·0.33H2O single crystal (FFH-S) delivers 30 mAh g−1 higher capacity (172 mAh g−1 at 0.1C) than the common FeF3·0.33H2O polycrystal (FFH-P). In-situ XRD combined with theoretic calculation elucidate the difference in lithium storage capacity. Instructive argument that single crystal octagon slices with [110] oriented growth provide more active sites for lithium ions intercalation contributes to the preparation of high performance iron fluoride cathode materials for rechargeable battery.
This work is to study the reasons for the relatively low efficiency of sulphur reduction (about 75%) in lithium–sulphur batteries. The two main reasons for that are suggested to be: the relatively low electrochemical activity of low order lithium polysulphides and blocking of the carbon framework of the sulphur electrode by insoluble products of electrochemical reactions – sulphur and lithium sulphide. The electrochemical activity of lithium polysulphides with different composition (Li2S n , n = 2–6) has been studied in 1 M solutions of CF3SO3Li in sulfolane. It is shown that lithium polysulphides including lithium disulphide are able to electrochemically reduce with efficiency close to 100%. The electrochemical activity of lithium polysulphides decreases with the order. The order of lithium polysulphides affects the value of voltage of discharge plateaus but not the efficiency of sulphur reducing in the lithium polysulphides species. The relatively low efficiency of sulphur reduction in the lithium–sulphur batteries is more likely caused by blocking of carbon particles in the sulphur electrode by insoluble products of electrochemical reactions (sulphur and lithium sulphide). This prevents the electrochemical reduction of low order lithium polysulphides and especially lithium disulphide.
An experimental co-generation power plant (CGPP-10) using aluminum micron powder (with average particle size up to 70μm) as primary fuel and water as primary oxidant was developed and tested. Power plant can work in autonomous (unconnected from industrial network) nonstop regime producing hydrogen, electrical energy and heat. One of the key components of experimental plant is aluminum–water high-pressure reactor projected for hydrogen production rate of ∼10nm3 h−1. Hydrogen from the reactor goes through condenser and dehumidifier and with −25°C dew-point temperature enters into the air-hydrogen fuel cell 16kW-battery. From 1kg of aluminum the experimental plant produces 1kWh of electrical energy and 5–7kWh of heat. Power consumer gets about 10kW of electrical power. Plant electrical and total efficiencies are 12% and 72%, respectively.
In this work, graphene oxide (GO) was synthesized through Hummer's method and reduced to graphene (RGO) through thermal reduction. Then, a composite was prepared from GO and functionalized carbon nanotube namely GO/CNT under ultrasonic irradiation and finally was converted to RGO/CNT by heating to be used as the cathode material in the lithium-air battery. The physical characterization of synthesized composite was accomplished using X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and N2-adsorption-desorption techniques. The specific surface area of the composite was 564.48m2/g. The electrochemical efficiency of composite was evaluated through charge-discharge cycleability and electrochemical impedance spectroscopy analysis. The electrochemical tests showed that the storage capacity was about 9000mA·h/g at 100mA/g current density. The cyclic performances of prepared electrodes were examined during 50cycles. Results exhibited an appropriate electrochemical performance for this composite to reduce and generate oxygen in aprotic medium.
Electrode materials, having a different graphitic character, are investigated by using a zero-gap flow field cell configuration for vanadium redox flow battery applications (VRFBs). Carbon felt (CF) and carbon paper (CP) are used as electrodes for the membrane–electrode assemblies (MEAs) realization. The samples are electrochemically characterized both as-received and after chemical treatment by using a 5cm2 single cell. A Nafion 117 membrane is used as polymer electrolyte separators. A MEAs scale-up from 5 to 25cm2 is carried out in order to assembly a 3-cells short stack in series connected. Charge–discharge cycles are carried out both in a small area single cell and in a 3-cells short stack for all samples. CF treated and untreated samples show SOC values of 45% vs. 22% at 60mAcm−2, respectively. After the chemical treatment, the worst performance of the CF sample is attributed to the mass transport issues due to the beginning of corrosion phenomena. On the contrary, CP treated electrode shows a better energy efficiency values than raw sample (72% vs. 67% at 60mAcm−2) without any morphology change on the electrode surface. A proper stack assembly and flow field scale-up record similar performance to the small single cell configuration.
The rapid growth of Renewable Energy Sources (RES) power plants connected to the grid has introduced new problems related to the safe and reliable operation of the electricity network from transmission to distribution sectors. New regulatory rules can promote RES producers to make a commitment on the energy amount that is likely to be supplied to the network. The present paper concerns the analysis of the energy production of a PV power plant from the economic point of view, with reference to the presence of regulatory rules. Costs of penalty and value of energy are compared, in order to evaluate the economic efficiency of the plant. Use of auxiliary energy storage devices is investigated, with the aim to determine the relevant dimensions that increase the economic efficiency of the PV plant. A software instrument that implements these algorithms is described and applied to a case study.
The objective of the study was to determine if different trunk muscles fatigued at a different rate in isometric axial rotation. Rotation is associated with a large number of back injuries. The fatigue behaviour may shed some light on possible reasons for such an association. Subjects were stabilized in an upright seated neutral posture in a specially designed and fabricated device—axial rotation tester such that the rotation could occur only in thoraco-lumbar region. Subjects performed isometric trunk rotation at 60% of their previously measured maximal voluntary contraction for a maximum duration of 2min or less if they could hold no longer. Surface electromyographic (EMG) was measured from seven trunk muscles bilaterally. Power spectra were calculated, the mean median frequency obtained at 10% intervals of the task cycle and compared in time within and between subjects. The EMG amplitudes were significantly different between right and left sides (p<0.01). The initial median frequencies of each muscle were significantly different from the other (p<0.01). The rate of decline of the median frequency for different trunk muscles were different (p<0.01). In isometric trunk rotation different trunk muscles demonstrated a different rate and magnitude of EMG fatigue. The latter is likely to alter the pattern of load sharing between muscles and predisposing musculoligamentous to injury either through stress concentration in deformed tissues or exceeding the strain rate tolerance in fatigue induced jerky motion (micromotion). Relevance to industry Low back injury continues to be one of the most common injuries. Rotation of the trunk is associated in over 60% of back injuries. The fatiguing behaviour of the trunk muscles provides an insight into possible control strategies such as reversing the direction of rotation periodically to allow recovery of fatigued muscles while still carrying out the task.
The sphere-like Fe(2-x)Cr x F5·H2O (x = 0, 0.03, 0.05, 0.07) composites with open framework structure are prepared via an IL based assisted approach, and served as the cathode material for Na-ion batteries (NIBs). The physicochemical and electrochemical properties of the Cr-doped Fe2F5·H2O cathode materials are systematically characterized. The results indicate that the Cr-doped materials not only reduce the crystalline size, but also remarkably enhance electronic conductivity. Meanwhile, the electrochemical tests further show that Fe1.95Cr0.05F5·H2O as the cathode active material of NIBs exhibits a high initial discharge capacity of 357 mAh g−1 and retains a discharge capacity of 171 mAh g−1 after 100 cycles at 0.1 C (1 C = 200 mAh g−1). Moreover, even at high rate of 1 C, it can still deliver a high discharge capacity of 147 mAh g−1. Compared with the Fe2F5·H2O, the Fe1.95Cr0.05F5·H2O shows higher discharge capacity, excellent cycle stability and better rate capability, which can be attributed to the improvement of structure stability and electronic conductivity due to the appropriate amount (5%) of Cr3+ doping. Therefore, the preparation of Cr-doped Fe2F5·H2O sample provides a unique perspective to enhance the electrochemical performance of Fe2F5·H2O, which is an essential step for the development of high specific energy sodium-ion batteries.
Consumers require lead–acid batteries with a high level of reliability, low cost and improved life, and/or with less weight and good tolerance to high-temperature operation. To reduce the thickness (weight) of the grids, the alloy materials must exhibit higher mechanical properties and improved corrosion resistance. In this study, the performance of negative and positive grids is evaluated in battery tests. The results demonstrate that continuously cast and expanded grids made from barium-doped lead–calcium–tin alloys meet performance requirements. For negative grids, improvement in the mechanical properties can lead to reliable thinner grids. For positive grids, the alloys exhibit improved mechanical properties and greater corrosion resistance. These features provide extremely good creep behaviour during battery operation such that performance under the hot SAE J240 test is superior to that achieved previously with expanded grids.
Theory of the charging and discharging process in electron-conducting polymer films at an electrode surface has been presented. It is based on the concept of two coexisting subsystems at the polymer matrix, ‘usual’ sites P which can exchange with the electrode by the electronic charge in a quasi-reversible manner, and sites D where intermolecular bonds between neighboring polymer molecules can be formed. The charging and discharging of the latter subsystem may be realized along different reaction pathways, e.g. via the bond formation after the generation of two cation radicals within such site D in the course of the anodic scan while the bond dissociation may take place via a partially discharged state of the intermolecular bond. This difference leads to a hysteresis in cyclic voltammograms, first of all to a significant mutual shift of the anodic and cathodic peaks of the current originated from the redox transformations of D sites. An important feature of the P sites extracted from experimental CV data is their broad energetic inhomogeneity (dispersion of their redox potentials) responsible for plateaus of the current observed at high charging levels in both directions of the potential scan. Several approaches to the numerical integration of the kinetic equations for the sites' states have been analyzed, and qualitative predictions of the theoretical model have been illustrated.
In this work a manganese oxide dispersed on a high surface area carbon powder at two ratios (Mn y O x /C) was evaluated as catalyst for the oxygen reduction reaction (ORR) in alkaline solutions. An impregnation method was used to prepare the catalysts, starting from a manganese nitrate precursor solution containing the carbon powder (Vulcan XC-72). A thin porous coating rotating disk electrode was employed to collect the experimental ORR polarization data and the results obtained were analyzed with the application of the flooded-agglomerate/thin film model for the catalyst layer. Results indicated that the reaction is sensitive to the manganese oxide to carbon ratio on the catalyst. The catalyst containing lower Mn y O x /C ratio tended to follow the peroxide pathway (2e− mechanism) forming peroxide ions. When the Mn y O x content is increased the complete reduction of oxygen to hydroxide ions pathway (the 4e− mechanism) takes place into some extent at low potentials due to the occurrence of a catalytic disproportionation of HO2 −.
X-ray micro computed tomography (μCT) is used for the morphological characterization of three-dimensional (3D) embroidered current collectors for LiFePO4 batteries. A conventional 2D planar configuration (aluminium foil as current collector) and two types of 3D embroidered configurations were compared. The μCT images were used to identify the different components in each configuration as well as to evaluate the corresponding volume fractions, porosities, mass fractions and apparent densities. Microtomographic scans complement analysis of typical galvanostatic charge/discharge cycles and confirm the suitability of 3D embroidered current collectors for their use in lithium-ion batteries.