batterydata/paper-abstracts huggingface dataset:
Fabricating electrode with hierarchical heterostructure is an effective method to incorporate the merits of different active materials into an electrode with desired electrochemical performance. However, heterostructure electrodes constructed layer by layer may increase the ion diffusion distances inadvertently when used for alkali metal ion batteries, though the synergistic effects of the components are exhibited. In this work, Co3O4 nanocrystallines (about 5 nm) anchor on ultrathin MnO2 nanosheets, which assemble hierarchical heterostructure hollow spheres (named as MnO2/Co3O4). When used as LIBs anode, the different dimensions of the components in MnO2/Co3O4 make them accessible for the electrolyte synchronously, without enlarging the ion diffusion distance. Moreover, the unique hierarchical hollow structure mitigates the internal mechanical stress brought by the volume variations upon cycling, preventing the electrode collapse. Therefore, the as-prepared MnO2/Co3O4 electrode not only delivers a high reversible capacity of 1209.0 mAh g−1 at 0.4 A g −1 over 300 cycles, but also exhibits long cyclic stability (a capacity of 581.8 mAh g−1 at 2.0 A g−1 after 1100 cycles). This work could provide new insight into heterostructure materials for batteries.
The purpose of this paper is, first, to summarize a theoretical perspective toward the development of a virtual reality innovation in education. Next, we will describe a virtual character project that is impacting the training of medical students in two institutions. In doing so, we will present a summary of three studies completed over the last 2 years, highlighting specific results from the research. Finally, we conclude with a discussion of the impact of these findings on the development and implementation of virtual reality systems for teaching and learning. It is our hope that through providing this study of a virtual reality scenario—experienced by over 100 end-users—from an educational concepts perspective will help others aiming to apply virtual reality to education.
Lithium-sulfur (Li-S) batteries have become a research hotspot due to their high energy density, environment friendliness and low-cost. But commercial applications are hampered by rapid capacity fading and low sulfur content. Herein, the composite of integrating manganese oxide on graphene was prepared by a facile redox reaction between potassium permanganate (KMnO4) and graphene in acidic aqueous solution to solve the problems of the Li-S batteries. X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) and transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) analysis show that sulfur was uniformity coated on G/MnO2 composite. TG indicated that the G/MnO2/S composites contained 76.56wt% active sulfur. The prepared cathode of G/MnO2/S composites exhibited excellent rate performance and cycle stability. At a high rate of 1C, its maximum discharge capacity reached 908mAhg−1 and its average capacity decreasing rate was only 0.105%/cycle when running over 500cycles. The interaction mechanism of MnO2 with polysulfides was investigated by adsorption tests and XPS analysis. The excellent electrochemical performance might be due to a combination of adsorption or catalytic properties of MnO2, and the conductivity network of graphene.
The novel ternary composites, conductive polymers (CPs)/graphene oxide (GO)@sulfur composites were successfully synthesized via a facile one-pot route and used as cathode materials for Li-S batteries The poly(3,4-ethylenedioxythiophene) (PEDOT)/GO and polyaniline (PANI)/GO composites were prepared by interface polymerization of monomers on the surface of GO sheets. Then sulfur was in-situ deposited on the CPs/GO composites in same solution. The component and structure of the composites were characterized by XPS, TGA, FTIR, SEM, TEM and electrochemical measurements. In this structure, the CPs nanostructures are believed to serve as a conductive matrix and an adsorbing agent, while the highly conductive GO will physically and chemically confine the sulfur and polysulfide within cathode. The PEDOT/GO@S composites with the sulfur content of 66.2wt% exhibit a reversible discharge capacity of 800.2mAhg−1 after 200 cycles at 0.5C, which is much higher than that of PANI/GO@S composites (599.1mAhg−1) and PANI@S (407.2mAhg−1). Even at a high rate of 4C, the PEDOT/GO@S composites still retain a high specific capacity of 632.4mAhg−1.
This paper reviews the literature on the subject albeit approaching hybrid micro-generation power systems from a systems thinking (ST) and cybernetics standpoint, viewing them as dynamically complex adaptive systems (CAS) coupled with and supplying to a set of homes termed a sustainable block in a rural setting. Here homeostatic regulation (HR) and control play a vital role in reaching efficient equilibrium towards reconciling power supply and demand response management. Unlike most of the work reviewed in the literature, the focus here is on supervisory control of grid-connected micro-generation systems without energy storage, aiming towards building energy efficiency, thriftiness and sustainability in energy consumption. Building on homeostatic control (HC) principles first introduced by F.C. Schweppe in 1979, the paper explores the concepts of sustainability and sustainable hybrid energy systems (SHES) applied to micro-generation, focusing on operational aspects rather than on socio-economic, environmental or regulatory ones. A concrete theoretical model for building a SHES is presented for a proposed grid-connected renewable microgrid. The model seeks to reconcile power supply and demand towards efficient equilibrium (homeostasis) proposing reward-based criteria for controlling renewable electricity supply and consumption in rural communities in Chile. Discussion and recommendations are also offered stating that energy sustainability (ES) is essentially a systems issue, and one where ES is first and foremost a structural, organizational and operational property which is in the very nature of the system itself – it is built into it – rather than explained by exogenous factors.
Objective Periodic limb movements in sleep (PLMS) show a time-of-night pattern, with most movements at the beginning of the night. Our study aimed to determine whether this pattern is due to an endogenous circadian rhythm, like that in the related movement disorder Restless Legs Syndrome (RLS). Methods Four healthy older adults with a screening PLMI>20 were studied in an inpatient forced desynchrony protocol with an imposed sleep–wake cycle of 20h for 12 “nights,” allowing separation of circadian and sleep homeostatic influences on leg movements. We recorded sleep polysomnographically throughout each scheduled episode, including left and right anterior tibialis EMG. Results PLMS in Stage 2 showed both a significant time-within-sleep pattern and a significant circadian rhythm. The circadian rhythm in PLMS peaked at the circadian phases when usual sleep onset occurs, preceding the evening rise in melatonin secretion. Conclusions In our subjects, the circadian pattern of PLMs expression was very similar to that previously reported in patients with RLS. This evidence for a circadian rhythm in PLMS has implications for treatment and provides direction for future studies of the pathophysiology of this movement disorder.
A free-standing electrode composed of carbon-coated Li4Ti5O12 nanosheets and reduced graphene oxide (designated as LTO-C/RGO) is fabricated for Na storage by modified vacuum filtration and subsequent annealing. In this process, graphene oxide with negative charges and LTO-C nanosheets with abundant charged ions are self-assembled into the nanocomposite based on the screening effect of electrostatic repulsion. The unique structure of the confined LTO-C nanosheets in a highly conductive interconnected RGO network not only promotes the reaction kinetics and structural stability of the electrodes during Na+ insertion/extraction, but also provides plenty of interfacial sites for Na+ adsorption giving rise to additional interfacial Na storage. The free-standing LTO-C/RGO anode for sodium ion battery exhibits a high capacity of 166 mAhg−1 at 1 C, good rate capability of 98.7 mAhg−1 at 5 C, and superior cyclic performance of 114 mAhg−1 at 2 C after 600 cycles. The materials boasting superior Na storage have large potential in high-performance sodium ion batteries in portable, flexible and wearable electronics.
β-CoOOH coated spherical β-NiOOH powders were synthesized as the positive electrode material for a new type of alkaline Zn-NiOOH battery. The scanning electron microscope (SEM), X-ray diffraction (XRD), inductively coupled plasma-atomic emission spectroscopy (ICP-AES), storage stability and electrochemical properties of the samples were investigated. The results showed that the β-CoOOH coated spherical β-NiOOH exhibited superior electrochemical performance and storage stability than uncoated spherical β-NiOOH. AA size alkaline Zn-NiOOH batteries were assembled by directly using β-CoOOH coated spherical β-NiOOH as the positive electrode material. The discharge–charge experiments revealed that the alkaline Zn-NiOOH battery displayed longer discharge time and higher discharge voltage than the conventional alkaline Zn-MnO2 battery under heavy load. Moreover, the Zn-NiOOH battery can be used not only conveniently as primary battery but also repeatedly as rechargeable battery.
Theoretical studies on unsymmetrical electrolyte salts, lithium difluoro(1,2-benzene-diolato(2-)-o,o′)borate (LDFBDB), and its derivatives, lithium bis[1,2-benzene-diolato(2-)-O,O′]borate (LBBB) and lithium fluoroborate (LiBF4) are carried out using density functional theory (DFT) method and B3LYP theory level. Bidentate structures are preferred. Based on these conformations, a linear correlation was observed between adiabatic ionization potential I p and the limiting oxidation potentials measured by linear sweep voltammetry, which supports experimental results that strongly electron-withdrawing substituent anions are more resistant against oxidation. The correlations were also observed between ionic conductivity and binding energy, solubility and theoretical set of parameters of anion. Wave function analyses have been performed by natural bond orbital (NBO) method to further investigate the cation–anion interactions.
Preparation of hierarchically porous, heteroatom-rich nanostructured carbons through green and scalable routes plays a key role for practical energy storage applications. In this work, naturally abundant lignocellulosic agricultural waste with high initial oxygen content, hazelnut shells, were hydrothermally carbonized and converted into nanostructured ‘hydrochar’. Environmentally benign ceramic/magnesium oxide (MgO) templating was used to introduce porosity into the hydrochar. Electrochemical performance of the resulting material (HM700) was investigated in aqueous solutions of 1M H2SO4, 6M KOH and 1M Na2SO4, using a three-electrode cell. HM700 achieved a high specific capacitance of 323.2 F/g in 1M H2SO4 (at 1 A/g, −0.3 to 0.9V vs. Ag/AgCl) due to the contributions of oxygen heteroatoms (13.5wt%) to the total capacitance by pseudo-capacitive effect. Moreover, a maximum energy density of 11.1Wh/kg and a maximum power density of 3686.2W/kg were attained for the symmetric supercapacitor employing HM700 as electrode material (1M Na2SO4, ΔE =2V), making the device promising for green supercapacitor applications.
Two disadvantages of lead acid batteries are poor power and energy densities and the necessity of relatively long recharging times. In this paper it is presented the results of ongoing work aimed at increasing both the positive active material (PAM) specific capacity and the positive plate charge acceptability. The experimental results show that adequate curing processes can be used to develop an interconnected structure among nanometric PbO2 particles to produce tubular electrodes with specific capacity higher than 180Ahkg−1 and maintain this value for 130 cycles with deep discharges. These PbO2 positive plates are expected to exhibit higher charge acceptability due to their larger PAM surface area as compared to conventional ones, but the results indicate that the high internal ohmic resistance of the grid/PAM zone limits the fast charge efficiency.
In this study, the storage capacity fade of a commercial 18650 lithium ion cell comprised with a composite cathode of LiNi0.5Mn0.3Co0.2O2 (NMC) and Li1.1Mn1.9O4 (LMO) and graphite anode at various depths-of-discharge (DoDs) and temperatures have been investigated. The results manifest that the capacity fading is strongly affected by the storage temperature and becomes prominent as temperatures higher than 45 °C. Results of the incremental capacity analysis of the charging/discharging curves cycled at C/25 rate under 25 °C after cells been stored at various DoDs at 60 °C for various durations are used to reveal the factors of storage capacity fade of this commercial cell in company with the results of post-mortem studies on the electrodes harvested from the 12 month storage-aged cells with SEM, EDX, XPS, XRD, and electrode capacity retention study with those of a fresh commercial cell for comparison. The contributions of these factors are also estimated quantitatively. The losses of active electrode materials are the main reasons of the storage capacity fade of the commercial cell comprised with composite NMC/LMO cathode and graphite anode, while the loss of lithium inventory is less influential. The degradation of the electrodes and the loss the lithium inventory are strongly DoD dependent.
This study presents a novel fuel sensor-less control scheme for a liquid feed fuel cell system that does not rely on a fuel concentration sensor. The proposed approach simplifies the design and reduces the cost and complexity of a liquid feed fuel cell system, and is especially suited to portable power sources, of which the volume and weight are important. During the reaction of a fuel cell, the cell's operating characteristics, such as potential, current and power are measured to control the supply of fuel and regulate its concentration to optimize performance. Experiments were conducted to verify that the fuel sensor-less control algorithm is effective in the liquid feed fuel cell system.
Porous carbon doped with transition metal oxides is rapidly becoming a key research topic in capacitive deionization desalination. This work reports a simple method for the synthesis of rGO doped with different ratios of nickel and cobalt oxides, i.e., 0, 10, 15, 25, 50, 75, and 100 wt%. The nanocomposite material was prepared via a modified Hammer`s method, followed by a hydrothermal doping process. The prepared samples were characterized using the X-Ray diffractometer (XRD), scanning electron microscope, energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy. TEM images revealed the arbitrary distribution of nickel and cobalt oxides in the rGO layer with an average particle size of 13 nm. The performance of the prepared materials was investigated ex situ, i.e., using a typical three-electrode cell. Also, it was verified in situ during the cell operation, i.e., using a two-electrode cell. Results showed that the performance of rGO was improved in the presence of Co3O4 and NiO nanoparticles as they form ternary Co3O4/NiO/rGO composites. Both XRD and EDX analyses confirmed the presence of Ni and Co in oxide form and attached to the rGO. The three-electrode cell measurements were from − 0.6 to 0.6 V in 1 M aqueous NaCl. The electrochemical measurements demonstrated that the rGO-25Ni, rGO-25Co, and rGO-15(50Ni-50Co) electrodes exhibited the best capacitive performance. Those samples achieved specific capacitances as high as 357 F g−1, 368.7 F g−1, and 461.5 F g−1, respectively. Such values are higher than those of electrodes based on rGO (82.77 F g−1), nickel oxide (2.98 F g−1), and cobalt oxide (3.8 F g−1). Better performance has been achieved using an equal ratio of bimetallic oxide loaded into the rGO than the single oxides or other ratios.
Effect of embedding aluminum porous metal foam inside the flow channels of an air-cooled Li-ion battery module was studied to improve its thermal management. Four different cases of metal foam insert were examined using three-dimensional transient numerical simulations. The effects of permeability and porosity of the porous medium as well as state of charge were investigated on the standard deviation of the temperature field and maximum temperature inside the battery in all four cases. Compared to the case of no porous insert, embedding aluminum metal foam in the air flow channel significantly improved the thermal management of Li-ion battery cell. The results also indicated that, decreasing the porosity of the porous structure decreases both standard deviation of the temperature field and maximum temperature inside the battery. Moreover, increasing the permeability of the metal foam drops the maximum temperature inside the battery while decreasing this property leads to improving the temperature uniformity. Our results suggested that, among the all studied cases, desirable temperature uniformity and maximum temperature were achieved when two-third and the entire air flow channel is filled with aluminum metal foam, respectively.
The main aim of this study is to evaluate the techno-economic role of the PV tracking technology in a hybrid photovoltaic-pump storage hydroelectric (PV-PSH) standalone power system. In this regard, a multi-objective optimization procedure is developed for the optimal design of a PV-PSH system and the developed procedure is separately implemented for the different types of PV tracking technologies such as horizontal and fixed-tilt panels (without any sun tracker), East-West oriented single-axis tracking, fixed-tilt azimuth tracking and dual-axis tracking systems. A coastal area in the south of Iran is considered as the case study; investment cost and loss of power supply probability (LPSP) are considered as the objective functions. Moreover, number of PV modules, turbine capacity, pipes diameters, and the volume, installation height and depth to diameter ratio of reservoir constitute the set of design variables and NSGAII is employed as the optimization algorithm. The results show that for the present case study, the fixed-tilt azimuth tracking technology leads to the minimum system cost with a suitable certainty under different LPSP values. Moreover, it results in the greatest match between the demanded and supplied power profiles. The results also illustrate that the appropriate selection of sun tracking technology in a hybrid PV-PSH system can lead to a savings of up to 18.2%. Finally, the economic superiority of the PV-PSH system over the common PV-battery system is investigated and proved for the case study.
Publisher Summary Network convergence involves the integration of different technologies and applications, which, when combined, create powerful new entities and products. One area of convergence that receives much emphasis is the merging of data, voice, and video on the network. It is a powerful concept and buzzword in networking circles. . It involves the melding of dissimilar network media, protocols, and applications to provide a network environment that is dramatically different that the previous one.. In the context of networking, convergence represents combining different technologies and applications. Currently, a major networking convergence issue receiving much attention is Internet Protocol (IP) telephony, which involves integrating voice and data. In IP telephony, digitized voice signals are converted to IP packets, which are then transmitted over the Internet. In this scenario, packet technology and the Internet are uniting voice and data such that traditional voice communication services are being delivered over an IP data network.
Objective We investigated the influence of the number of stimuli on signal-to-noise (S/N) ratio of CSERP. Methods CSERP from 20 normosmic subjects were obtained in response to stimulation with two olfactory (H2S and PEA) and a trigeminal (CO2) stimulant. For each of these odors, 160 stimuli were delivered into the right nostril (duration 200ms, mean ISI 30s) using a constant-flow, air-dilution olfactometer. For each EEG recording site (Fz, Cz, Pz, C3, C4), peak-to-peak amplitude N1P2 and noise amplitude levels were determined. Subsequently, S/N ratios were calculated. Results The S/N ratios for olfactory ERP generally improved for H2S and PEA. For responses to PEA, S/N ratios increased significantly up to 80 averages (S/N ratio=5.6). The number of stimuli for an optimal S/N ratio for trigeminal ERP was slightly lower, i.e. 60 averages (S/N ratio=7.9). Conclusions S/N N1P2 ratios in olfactory and trigeminal ERP significantly improve with an increasing number of responses averaged under these experimental conditions. This is mainly due to a reduction of noise level. Applying more stimuli has little additional effect on S/N ratio due to a concomitant decrease in signal amplitude. Significance An optimal S/N ratio is essential when recording CSERP in neurodegenerative disorders, where responses may be of low amplitude, and for medico-legal purposes.
A sulfur cathode is designed with three-dimensional (3D) cubic mesoporous carbon CMK-8 as the matrix of sulfur, and polypyrrole (PPY) as the wrapping layer. CMK-8 provides perfect 3D conductive network. Furthermore, PPY is coated onto the surface of CMK-8/sulfur (CMK-8/S) composite to inhibit the migration of lithium polysulfide and offer better lithium ion conductive channels. The microstructure and electrochemical performance of the PPY@CMK-8/sulfur (PPY@CMK-8/S) cathode are investigated systematically. The results show that PPY layer with about 50 nm thickness is coated uniformly on the surface of CMK-8/S. The Li–S battery with PPY@CMK-8/S as cathode material presents a discharge capacity of 937.8 mAh g−1 at 20 cycles and is stabilized at about 860 mAh g−1 after 100 cycles at 0.2C.
Manganese oxide with high tap density was prepared by decomposition of spherical manganese carbonate, and then LiMn2O4 cathode materials were synthesized by solid-state reaction between the manganese oxide and lithium carbonate. Structure and properties of the samples were determined by X-ray diffraction, Brunauer–Emmer–Teller surface area analysis, scanning electron microscope and electrochemical measurements. With increase of the decomposition temperature from 350°C to 900°C, the tap density of the manganese oxide rises from 0.91gcm−3 to 2.06gcm−3. Compared with the LiMn2O4 cathode made from chemical manganese dioxide or electrolytic manganese dioxide, the LiMn2O4 made from manganese oxide of this work has a larger tap density (2.53gcm−3), and better electrochemical performances with an initial discharge capacity of 117mAhg−1, a capacity retention of 93.5% at the 15th cycle and an irreversible capacity loss of 2.24% after storage at room temperature for 28 days.
A new electrode structure based on a three-dimensional mesoporous matrix was developed. Nanoparticles of γ-iron oxide (Fe2O3) were introduced into the mesopores of a carbon matrix (mesoporous carbon, CMK-3) by oxidizing metallic iron, which was electroplated in the matrix. The resulting structure was found to have a high charge–discharge capacity when used as the positive electrode of a lithium battery. The iron oxide nanoparticles bonded tightly to the electrically conductive electrode framework, and showed a high activity for the electrochemical reaction: Fe2O3 +6Li→3Li2O+2Fe.
Pulsed electromagnetic field (PEMF) is reported to be an effective adjunct for the management of nonunion long-bone fractures. Most studies implement PEMF treatment after 6 months or longer of delayed union or nonunion following fracture treatment. Despite these variations in treatment, the early application of PEMF following a diagnosis of a postoperative delayed union has not been specifically analyzed. In this study, the outcomes of postoperative delayed union of long-bone fractures treated with an early application of PEMF were evaluated as compared with a sham-treated control group.