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Preparation of LiFeO2–Li2MnO3 solid solution has been attempted using hydrothermal and solid state reactions. Three 10% Fe-doped Li2MnO3 samples (Fe/(Fe+Mn)=0.1) with different average particle sizes could be obtained by both methods. The initial charge capacities for these cathodes were sensitive to the preparation method; the capacity up to 4.3V is 45mAh/g for the hydrothermally-obtained sample, 24mAh/g for the post-annealed sample after hydrothermal-treatment at 673K, and 6mAh/g for the sample obtained by solid state reaction at 1173K. 57 Fe Mössbauer spectra detect the oxidation of Fe3+ to Fe4+/reduction of Fe4+ to Fe3+ after initial charging/discharging for the hydrothermally obtained sample. The observed Fe3+/4+ redox voltage is between 4.0 and 4.5V which is lower than that predicted (5V) for Fe-doped LiMn2O4. This suggests that hydrothermally synthesized Fe-doped Li2MnO3 is an environmentally–friendly candidate as cathode material, involving a Fe3+/4+ redox reaction for rechargeable lithium batteries.
It is desirable to develop electrode materials for advanced rechargeable batteries with low cost, long life, and high-rate capability. Pyrite FeS2, as an easily obtained natural mineral, has been already commercialized in primary lithium batteries, but encountered problems in rechargeable batteries with carbonate-based electrolytes due to the limited cycle life caused by the conversion-type reaction (FeS2 + 4M → Fe + 2M2S (M = Li or Na)). Herein, we demonstrate that FeS2 microspheres can be applied in room-temperature rechargeable sodium batteries with only the intercalation reaction by simultaneously selecting a compatible NaSO3CF3/diglyme electrolyte and tuning the cut-off voltage to 0.8 V. A surprisingly high-rate capability (170 mA h g−1 at 20 A g−1) and unprecedented long-term cyclability (∼90% capacity retention for 20000 cycles) has been obtained. We suggest that a stable electrically conductive layer-structured NaxFeS2 was formed during cycling, which enables the highly reversible sodium intercalation and deintercalation. Moreover, 18650-type sodium batteries were constructed exhibiting a high capacity of ∼4200 mA h (corresponding to 126 W h kg−1 and 382 W h L−1) and a capacity retention of 97% after an initial 200 cycles at 4 A during charge–discharge. This shows that the production of rechargeable sodium batteries with FeS2 microspheres is viable for commercial utilization.
Introduction adult-onset autosomal dominant leukodystrophy (ADLD) is a rare inherited disorder due to a duplication of lamin-B1 (LMNB1) gene. The aim of this study was to investigate brain metabolic and microstructural alterations by using advanced MR techniques. Methods we performed brain MR scans including single-voxel proton-MR Spectroscopy (1H-MRS) of the lateral ventricles and parietal white matter and diffusion tensor imaging (DTI) in 4 subjects with LMNB1 gene duplication, 6 non-mutated relatives and 7 unrelated healthy controls. Cervical and thoracic spinal cord MR was performed in three symptomatic subjects with LMNB1 mutation. All participants underwent clinical and neuropsychological evaluation. Results all subjects with LMNB1 gene duplication presented pathological accumulation of lactate in lateral ventricles CSF and no alterations of brain white matter absolute metabolites concentrations or metabolites/Cr ratios. We found increased white matter intra- and extracellular water transverse relaxation times. Tract-based spatial statistics analysis detected a significantly reduced fractional anisotropy in the genu of the corpus callosum in mutated cases compared to unrelated healthy controls and non-mutated relatives. Moreover, we detected different degrees of the typical white matter signal intensity alterations and brain and spinal atrophy at conventional MRI in symptomatic subjects with LMNB1 mutation. A mild impairment of executive functions was found in subjects with LMNB1 gene mutation. Conclusion in subjects with LMNB1 gene duplication, we found a pathological increase in CSF lactate, likely due to active demyelination along with glial activation, and microstructural changes in the genu of the corpus callosum possibly underpinning the mild neuropsychological deficits.
α,ω-Diimidazoliumalkylene salts (C n (ImX)2; n=2–8) were prepared as a new type of room temperature molten salts. By changing their counter anion from bromide to bis(trifluoromethylsulfoneimide), the salt property was drastically changed and was revealed to be due to the formation of room temperature molten salts except for the system with n=2. DSC measurement suggested that C n (ImTFSI)2 with n=3 and 4 formed super cooled liquids and those with n=6 and 8 were amorphous (showing no melting point). These amorphous compounds showed ionic conductivity of about 10−3 S cm−1 at 30°C. The salts with n=6 and 8 showed much higher ionic conductivity than others. This high ionic conductivity was kept even after the addition of lithium salt (LiTFSI). Comparing with the similar room temperature molten salts, α,ω-diimidazolium-poly(ethylene oxide) salts, C n (ImTFSI)2 showed little temperature dependence of ionic conductivity even when the matrix contains lithium salt. It was based on the low activation energy of matrix derived from the absence of strong ion–dipole interaction between lithium ion and ether oxygens.
Objective To develop a reliable, objective and sensitive measure of axial trunk rotations in PD, which can be applied in an ambulatory setting. Methods To quantify turning motion, two angular velocity transducers attached to the lower back measured angular velocity of the trunk in the yaw plane (i.e., around the longitudinal axis) and the roll plane (i.e., medio-lateral movements) in freely moving subjects who were instructed to walk and make various types of turning movements. Results Turn duration was longer in PD patients compared to controls. Peak yaw and peak roll angular velocities were lower in PD patients compared to controls during all turning tasks. Conclusions This new approach to measure trunk sway during a simple turning task might serve as an instrument to objectively quantify turning while walking in PD. Significance It proves difficult to objectively assess turning performance based upon history taking or clinical examination alone. Objective and easy measurement of axial turning in PD might be used for clinical evaluation, but also in a domestic setting as outcome measure in intervention studies. Further research should focus on the clinical relevance of the new quantitative approach described in this paper, e.g., to detect freezing of gait episodes.
The aim of this study was to investigate the underlying structure of eight working memory tests used to assess prefrontal dysfunction in schizophrenia research [Letter–Number Span (LNS), Digit–Symbol Test (DST), Trail-Making Test B (TMT-B), Delayed Response Task (DRT) for spatial working memory, Subject Ordered Pointing Task (SOPT), Dual Tasking (DUAL), Continuous Performance Test (CPT)-Identical Pairs, Wisconsin Card Sorting Test (WCST)]. Sixty-six patients with schizophrenia showed significant working memory performance deficits in all tests when compared with 45 healthy controls. Performance was not systematically related to psychopathology. When differences in IQ were controlled, working memory deficits remained stable except in the WCST. Principal components analyses yielded three components for healthy controls: a comparator function of the central executive defined by a comparison of working memory content with information from the environment, an allocation of attentional resources function, and a maximum storage capacity function. The comparator and maximum storage functions could be replicated in the schizophrenia sample. However, the allocation function did not emerge as an independent component and was replaced by a component defined by the WCST. These findings suggest that working memory is not a unitary concept but rather should be conceptually differentiated as functions of transient storage/active rehearsal capacity and central executive manipulation supporting a previous suggestion proposed by Perry et al. [Schizophr. Bull. 27 (2001) 157].
Hard carbons emerge as one of the most promising candidate for an anode of Na-ion batteries. This research focuses on the carbon monolith derived from resorcinol-formaldehyde (RF) gels as a model hard carbon electrode. A series of binder-free monolithic carbon electrodes heat-treated at varied temperatures allow the comparative investigation of the correlation between carbon nanotexture and electrochemical Na+-ion storage. The increase in carbonization temperature exerts a favorable influence on electrode performance, especially in the range between 1600 °C and 2500 °C. The comparison between Li+- and Na+-storage behaviors in the carbon electrodes discloses that the Na+-trapping in nanovoids is negligible when the carbonization temperature is higher than 1600 °C. On the other hand, the high-temperature sintering at 2500–3000 °C enlarges the resistance for Na+-insertion into interlayer spacing as well as Na+-filling into nanovoids. In addition, the study on the effect of pore size clearly demonstrates that not the BET surface area but the surface area related to meso- and macropores is a predominant factor for the initial irreversible capacity. The outcomes of this work are expected to become a benchmark for other hard carbon electrodes prepared from various precursors.
This work presents a non-destructive in-situ method for probing degradation mechanisms in large format, operating, commercial lithium-ion batteries by neutron diffraction. A fresh battery (15 Ah capacity) was shown to have a uniform (homogeneous) local state of charge (SOC) at 4.0 V (9 Ah SOC) and 4.2 V (15 Ah SOC), with 1.33 C and 2.67 C charging rates, respectively. This battery was then aggressively cycled until it retained only a 9 Ah capacity, 60% of its original value. Inhomogeneous deterioration in the battery was observed: near the edges, both the graphite anode and the spinel-based cathode showed a significant loss of capacity, while near the central area, both electrodes functioned properly. An SOC mapping measurement of the degraded battery in the fully charged state (4.2 V) indicated that the loss of local capacity of the anode and cathode is coupled.
Health-related quality of life (HRQoL) before treatment may predict survival of patients with non-small-cell lung cancer (NSCLC). We investigated the predictive role of HRQoL after the initial treatments, on the survival of these patients.
The synthesis and characterization of novel ionic liquid (ILs) based gel polymer electrolytes for application in sodium-ion (Na+) batteries is reported. It comprises a 0.2M solution of NaN(CF3SO2)2 (sodium bis(trifluoromethylsulfonyl) imide) in mono and dicationic imidazolium-based ionic liquids immobilized in a poly(vinylidene fluoride)-hexafluoropropylene copolymer matrix. The membranes offer acceptable ionic conductivity, up to 2.2×10−4 S cm−1 at room temperature, with excellent thermal and electrochemical stabilities. The useful thermal stability reached up 150 °C and decomposition only starts at about 400 °C, while electrochemical stability window comprises from 1.5 V to 5.0 V vs. Na/Na+. Na+ transference values ( t N a + ) are in the range of 0.1 to 0.5, indicating a contribution of anionic transport (TFSI− anion) and component ions of ionic liquid to the total ionic conductivity. The nature of Na+ coordination and the formation of Na+-complexes were elucidated through Raman spectroscopy. The average number of TFSI coordinated to Na+ (n) allowed to know the contribution of the formed complexes in ionic mobility mechanism in the gel electrolytes. The effect of side chain length in oxyethylene-functionalized imidazolium mono and dicationic RTILs on both structural and electrochemical properties were discussed. Results obtained demonstrate promising characteristics of the membranes, being suitable candidates to be used in rechargeable sodium batteries.
Mechanical processes such as ball milling trigger lattice deformations into particles. The electrochemical performances of the electrode materials used for Li-ion batteries depend on Li+ mobility within the crystal structure. Therefore, the preparation of electrode particles that contain no lattice deformations is required. However, electrode particles are subjected to mechanical stresses during manufacturing processes such as grinding, mixing, and coating of powders. In this study, the introduction of lattice strains and defects into the LiNi0.5Mn1.5O4 (LNMO) spinel by a simple ball-milling process is investigated, together with the relationship between lattice deformation and cathode properties. Lattice strain accumulates in the LNMO crystal with increased milling time, but the crystallite size of the distorted particles reduces in order to mitigate this effect. Although mechanical treatment leads to a decrease in the first discharge capacity, there is a recovery in capacity after the second discharge owing to crystal rearrangement that occurs after the initial extraction and insertion of Li+ from the distorted LNMO spinel. Nonetheless, excessive lattice deformation in the LNMO spinel, which contains a three-dimensional diffusion pathway for Li+, disturbs fast migration. The design and quality management of electrode particles throughout the manufacturing process are key factors for improving battery performances.
Hybrid conversion of solar radiation implies simultaneous solar radiation conversion into thermal and electrical energy in the PV/Thermal collector. In order to get more thermal and electrical energy, flat solar radiation reflectors have been mounted on PV/T collector. To obtain higher solar radiation intensity on PV/T collector, position of reflectors has been changed and optimal position of reflectors has been determined by both experimental measurements and numerical calculation so as to obtain maximal concentration of solar radiation intensity. The calculated values have been found to be in good agreement with the measured ones, both yielding the optimal position of the flat reflector to be the lowest (5°) in December and the highest (38°) in June. In this paper, the thermal and electrical efficiency of PV/T collector without reflectors and with reflectors in optimal position have been calculated. Using these results, the total efficiency and energy-saving efficiency of PV/T collector have been determined. Energy-saving efficiency for PV/T collector without reflectors is 60.1%, which is above the conventional solar thermal collector, whereas the energy-saving efficiency for PV/T collector with reflectors in optimal position is 46.7%, which is almost equal to the values for conventional solar thermal collector. Though the energy-saving efficiency of PV/T collector decreases slightly with the solar radiation intensity concentration factor, i.e. the thermal and electrical efficiency of PV/T collector with reflectors are lower than those of PV/T collector without reflectors, the total thermal and electrical energy generated by PV/T collector with reflectors in optimal position are significantly higher than total thermal and electrical energy generated by PV/T collector without reflectors.
Temperature imposes a diversified set of problems to the successful operation of Li-ion batteries. Graphite anodes, in particular, are especially fragile at elevated temperatures, as continuous electro-reduction processes cause detrimental transformations in the solid electrolyte interphase (SEI). In the present work, we investigate the factors that contribute to the performance decay of graphite in cells containing a pyrrolidinium-based ionic liquid, exploring the effect of different lithium salts, electrode formulations and test conditions on the thermal resilience of the system. We show that the contribution of FSI anions to the SEI provides remarkable protection to graphite particles, preventing the electronic isolation of electrode domains. We further propose that the positive activity exhibited by these species is associated with their specific decomposition pathway. A coulombic efficiency of 99.4% could be achieved in Li/graphite half-cells at 90 °C, demonstrating that compositional control of the solid electrolyte interphase is essential to extend the environmental range of Li-ion batteries.
Layered Ni-rich transition metal oxides exert great potential as high-capacity cathode materials for lithium-ion batteries. However, structural degradation during lithiation/delithiation hinders the cathode materials for commercial utilization. Herein, PO4 3− polyanion and Mn4+ cation are co-doped into Ni-rich LiNi0.80Co0.15Al0.05O2 cathode to improve the structural stability and electrochemical performance. The effects of PO4 3− and Mn4+ co-existence on phase, crystal structure, element valence state, electrochemical performance and phase transition during lithiation/delithihation are systematically investigated. The results show that moderate content of PO4 3− and Mn4+ co-doping can enlarge the channel for Li+ lithiation/delithiation, lower the cationic mixing, and suppress the structural degradation during cycling. With the stabilization role of Mn4+ and PO4 3−, the material with moderate amount of dopants shows remarkable enhanced electrochemical performance, especially at harsh condition. In the cell potential of 2.7–4.3 V, the 3% PO4 3− and Mn4+ co-doped cathode shows a reversible discharge capacity of 204 mAh g−1 at 0.1C, outstanding cycling stability with a capacity of 174 mAh g−1 and capacity retention of 85.5% at 1C after 100 cycles, especially, a superior discharge capacity of 157.8 mAh g−1 at 5C. Even at elevated temperature of 55 °C, the cathode retains 80.9% of initial capacity (195 mAh g−1) at 1C after 100 cycles.
Archaeological recording of structures and excavations in high mountain areas is greatly hindered by the scarce availability of both space, to transport material, and time. The Madriu-Perafita-Claror, InterAmbAr and PCR Mont Lozère high mountain projects have documented hundreds of archaeological structures and carried out many archaeological excavations. These projects required the development of a technique which could record both structures and the process of an archaeological excavation in a fast and reliable manner. The combination of DGPS, close-range terrestrial stereophotogrammetry and voxel based GIS modelling offered a perfect solution since it helped in developing a strategy which would obtain all the required data on-site fast and with a high degree of precision. These data are treated off-site to obtain georeferenced orthoimages covering both the structures and the excavation process from which site and excavation plans can be created. The proposed workflow outputs also include digital surface models and volumetric models of the excavated areas from which topography and archaeological profiles were obtained by voxel-based GIS procedures. In this way, all the graphic recording required by standard archaeological practices was met.
SiOx owing to high reversible capacity and moderate volume expansion has been attracting a lot of attention as state-of-the-art anodes for the next generation of Li-ion batteries. However, poor cycling performance and poor rate capability, respectively associated with detrimental volume expansion and insulative amorphous SiO2, are still challenging issues which need to be addressed for the actual employment as anodes for Li-ion batteries. In this regard, here we design, synthesize, characterize and test carbon coated sheet-like SiO1.1 nanocomposites formed by Si-nanodomains confined inside amorphous SiO2 (nano-Si/a-SiO2). As a proof-of-concept, we achieve sheet-like SiOx nanocomposites via in-situ transformation of delaminated siloxene. In particular, self-prepared siloxene with oxygen-inserted Si6 rings terminated with H and OH ligands is prepared by delamination of CaSi2 in dilute HCl. Importantly, the resulting carbon coated nano-Si/a-SiO2 material shows enhanced reaction kinetics and structural stability leading to 946 mAh g−1 capacity at 0.15Ag−1. Intriguingly, 38.0% (~360 mAh g−1) of the maximum capacity is maintained even at 7.5Ag−1, corresponding to a remarkable less than 3min charge/discharge time. Finally, the electrode shows merely 24% of volume expansion and minor cracks with capacity retention of 92% after 300 cycles at 7.5Ag−1.
From the perspective of global warming mitigation and depletion of energy resources, renewable energy such as wind generation (WG) and photovoltaic generation (PV) are getting attention in distribution systems. Additionally, all-electric apartment houses or residence such as DC smart houses are increasing. However, due to the fluctuating power from renewable energy sources and loads, supply-demand balancing of power system becomes problematic. Smart grid is a solution to this problem. This paper presents a methodology for optimal operation of a smart grid to minimize the interconnection point power flow fluctuation. To achieve the proposed optimal operation, we use distributed controllable loads such as battery and heat pump. By minimizing the interconnection point power flow fluctuation, it is possible to reduce the electric power consumption and the cost of electricity. This system consists of photovoltaic generator, heat pump, battery, solar collector, and load. To verify the effectiveness of the proposed system, results are used in simulation presented.
A simple high-energy ball milling combined with spray-drying method has been developed to synthesize LiFePO4/carbon composite. This material delivers an improved tap density of 1.3g/cm3 and a high electronic conductivity of 10−2 to 10−3 S/cm. The electrochemical performance, which is especially notable for its high-rate performance, is excellent. The discharge capacities are as high as 109mAh/g at the current density of 1100mA/g (about 6.5C rate) and 94mAh/g at the current density of 1900mA/g (about 11C rate). At the high current density of 1700mA/g (10C rate), it exhibits a long-term cyclability, retaining over 92% of its original discharge capacity beyond 2400 cycles. Therefore, the as-prepared LiFePO4/carbon composite cathode material is capable of such large-scale applications as hybrid and plug-in hybrid electric vehicles.
Law enforcement and intelligence agencies generally have access to a number of rich data sources, both structured and unstructured, and with the advent of high performing entity resolution it is now possible to fuse multiple heterogeneous datasets into an explicit generic data representation. But once this is achieved how should agencies go about attempting to exploit this data by proactively identifying criminal events and the actors responsible? The authors will outline an effective generic method that; computationally extracts minimally overlapping contextual subgraphs, then uses these subgraphs as the basis to construct a mesoscopic graph based on the intersections between the subgraphs, enabling knowledge discovery from these data representations for the purpose of maximally disrupting terrorism, organised crime and the broader criminal network.