batterydata/paper-abstracts huggingface dataset:
The Cl-doping Li3V2(PO4)3/C (LVP/C) cathode materials were synthesized by a sol–gel method. The effects of Cl-doping amount on electrochemical properties, structure and morphology of Li3V2(PO4)3/C were studied by electrochemical impedance spectroscopy, cyclic voltammetry, X-ray diffraction, FTIR spectrum and scanning electron microscopy. The results indicate that the Li3V2(PO4)2.88Cl0.12/C composite presents an excellent discharge capacity as high as 106.95mAhg−1 after 80 cycles at 8C. The same monoclinic structure of Li3V2(PO4)2.88Cl0.12/C sample can be obtained from XRD analysis while the particle size is smaller than that of pristine sample (x =0). The FTIR results further confirm the substitution of Cl− for PO4 3−. The reasons for the relatively enhanced capability are attributed to the decreased polarization and the reduced charge transfer resistance of electrode, with the suitable Cl-doping amount of x =0.12.
Abstract The decision to use a new material has technical, economic, and environmental consequences. The goal of this chapter is to help clarify quickly the use, possibilities, and problems of thermosets and composites. Consumptions, engineering and specific properties, costs of plastics and composites, are compared with metals and some other conventional materials. After some basic reminders concerning thermosets, thermoplastics, composites, and related processing methods, the designer’s main problems are examined, taking into account the economic, technical, marketing, sustainability, and environmental requirements. Recycling, plastics of renewable sources and some weaknesses of polymer materials end this chapter. The final choice of the design team will result from many iterations concerning the functional properties, the environmental constraints, the possibilities to produce the part in the required quantities, and the price. Market study specialists, associations and institutes are quoted to ease in-depth studies by the reader.
Reduction in cost of lithium ion batteries is essential to the cost walk of electrified vehicles. Electrode microstructure can significantly affect capacity and thus cost. The effect of structure – host–guest versus core–shell – on electrochemical characteristics of transition metal oxide/conducting polymer nanocomposites as the active component of the positive electrode of lithium batteries was studied using two types of polypyrrole based hybrids one prepared with vanadium oxide xerogel and the other with crystalline V2O5. It was shown that the host–guest structure can provide substantially higher stability under charge–discharge cycling, faster transport of lithium ions and allows redox processes at higher potentials.
Li and Mn-rich layered oxide cathodes although exhibit high specific capacities ≥240 mAh g−1, suffer from capacity fading and discharge voltage decay during prolonged cycling to potential higher than 4.5 V. This study aimed at exploring an interesting Co-free Li and Mn rich cathode material and to understand how the upper potential applied affects its capacity and average discharge voltage upon prolonged cycling. Li1.17Ni0.25Mn0.58O2 cathodes were explored in Li cells by galvanostatic charge-discharge cycling in several potential ranges. The specific capacity, capacity retention and average discharge voltage were compared with and without activation to 4.6–4.8 V when cycled to different upper potential limits. This cathode material exhibited a high discharge capacity of 242 mAh g−1 when cycled in the potential range of 2.3–4.6 V after activation to 4.8 V with gradual capacity fading and average discharge voltage decreasing from 3.62 V to 3.55 V during 100 cycles. When cycled in the potential range of 2.3–4.3 V after activation to 4.6 V, it exhibited a relatively stable capacity >160 mAh g−1 and stable average discharge voltage of 3.61 V, during 100 cycles. Thus, with optimized operating condition, the Li and Mn-rich cathode material Li1.17Ni0.25Mn0.58O2 is promising for lithium-ion batteries.
Fibromyalgia syndrome (FMS) is a complex pain disorder, characterized by diffuse pain and cognitive disturbances. Abnormal cortical oscillatory activity may be a promising biomarker, encouraging non-invasive neurostimulation techniques as a treatment. We aimed to modulate abnormal slow cortical oscillations by delivering transcranial alternating current stimulation (tACS) and physiotherapy to reduce pain and cognitive symptoms. This was a double-blinded, randomized, crossover trial conducted between February and September 2018 at the Rehabilitation Unit of a teaching Hospital (NCT03221413). Participants were randomly assigned to tACS or random noise stimulation (RNS), 5 days/week for 2 weeks followed by ad hoc physiotherapy. Clinical and cognitive assessments were performed at T0 (baseline), T1 (after stimulation), T2 (1 month after stimulation). Electroencephalogram (EEG) spectral topographies recorded from 15 participants confirmed slow-rhythm prevalence and provided tACS tailored stimulation parameters and electrode sites. Following tACS, EEG alpha1 ([8–10] Hz) activity increased at T1 (p = 0.024) compared to RNS, pain symptoms assessed by Visual Analog Scale decreased at T1 (T1 vs T0p = 0.010), self-reported cognitive skills and neuropsychological scores improved both at T1 and T2 (Patient-Reported Outcomes in Cognitive Impairment, T0–T2, p = 0.024; Everyday memory questionnaire, T1 compared to RNS, p = 0.012; Montréal Cognitive Assessment, T0 vs T1, p = 0.048 and T0 vs T2, p = 0.009; Trail Making Test B T0–T2, p = 0.034). Psychopathological scales and other neuropsychological scores (Trail Making Test-A; Total Phonemic Fluency; Hopkins Verbal Learning Test-Revised; Rey–Osterrieth Complex Figure) improved both after tACS and RNS but earlier improvements (T1) were registered only after tACS. These results support tACS coupled with physiotherapy in treating FMS cognitive symptoms, pain and subclinical psychopathology.
Semantic errors are a common type of slip of the tongue for normal speakers; they are also considered to be the hallmark of progressive diseases that affect semantic memory such as Alzheimer's Disease (AD) and semantic dementia. In unimpaired speakers, semantic errors have been shown to be affected by syntactic variables. For example, Marx (1999) has shown that speakers of a gendered language such as German tend to substitute a target with another word that shares the same grammatical gender with the target more often than chance would predict. This finding suggests that errors occur at a level at which lexical information about the target is activated and retrieved. Here, we assess whether such an effect of syntactic variables (gender) also holds in experimental tasks designed to induce errors in unimpaired speakers of Italian (another gendered language) and whether this effect can also be observed in the semantic errors produced in the same task by AD patients. We found that for the unimpaired speakers, the gender of the target word constrained the error committed, while this was not the case for the AD patients. We take this finding to suggest a different locus for the errors in the two populations: while the semantic errors by the unimpaired speakers occur because of mis-selection of a lexical entry due to lexical competition among semantically similar words, the errors by the AD patients occur because of insufficient activation of lexical representations.
This paper studies the important but unexplored relationship between R&D investment intensity and different components of stock price volatility. The total volatility of stock price is decomposed into a continuous component and a jump component. We find that firms with higher R&D investment intensity have less jump volatility of stock price. We explain the findings through a channel of stock liquidity and information disclosure. We argue that R&D-intensive firms prefer higher stock liquidity, and empirically document that they achieve higher stock liquidity by actively releasing R&D information. We apply a textual analysis technique and show that R&D-intensive firms voluntarily disclose more R&D information in 10-K, 10-Q and 8-K filings, resulting in higher stock liquidity and hence less jump volatility of stock price. The negative relationship between R&D investment intensity and jump volatility of stock price is more pronounced for financially constrained firms, which have stronger incentives to release R&D information and hence increase stock liquidity. Propensity-score matching approach and instrumental variable approach are used to address endogeneity. A rich set of robustness tests are conducted to confirm the findings.
PURPOSE The aim of this systematic review was to investigate the evidence of abnormal functioning of the mirror neuron system (MNS) in children and adults with developmental coordination disorder (DCD), through examination of imitation, motor imagery, and neuroimaging literature. METHODS The following databases were comprehensively searched for relevant articles: CINAHL Plus, Embase, MEDLINE, PsycINFO, Pubmed, and Web of Science. Full-text articles of all potentially relevant citations were obtained and assessed for eligibility by two authors. Outcome measures of interest at a motor behaviour level were any measures of imitation or motor imagery proficiency and, at a neurological level, were any measures of neural activity in MNS brain regions. Due to differences in outcome measures between studies and the variables reported, a narrative review was undertaken to synthesise findings from the studies. RESULTS Overall, 31 articles met the inclusion criteria. Children and adults with DCD display deficits imitating meaningful and novel gestures and demonstrate different response patterns to controls when undertaking complex motor imagery tasks. Children with DCD present reduced activation and connectivity of frontal, parietal, and temporal MNS regions. CONCLUSIONS Preliminary evidence indicates some deficit in the functioning of the MNS at a motor behaviour and neurological level. As no published neuroimaging studies have been designed specifically to explore MNS function, these results must be interpreted with caution. Further research to explore the MNS hypothesis in greater detail, particularly from a neuroimaging perspective, has the potential to provide information on the underlying mechanisms of DCD, inform future research into the aetiology of this disorder, and inform intervention approaches.
High-energy ball milling is used to recycle Si wafers to produce Si powders for negative electrodes of Li-ion batteries. The resulting Si powder consists in micrometric Si agglomerates made of cold-welded submicrometric nanocrystalline Si particles. Silicon-based composite electrodes prepared with ball-milled Si wafer can achieve more than 900 cycles with a capacity of 1200 mAh g−1 of Si (880 mAh g−1 of electrode) and a coulombic efficiency higher than 99%. This excellent electrochemical performance lies in the use of nanostructured Si produced by ball milling, the electrode formulation in a pH 3 buffer solution with CMC as binder and the use of FEC/VC additives in the electrolyte. This work opens the way to an economically attractive recycling of Si wastes.
High-energy ball milling was used to modify the physico-chemical and the electrochemical hydrogenation properties of Mg50Ti50 alloy via the addition of Pd. This was done by first ball milling Mg and Ti together for (20− x) hours. 3.3at.% Pd was then added and ball milling was resumed for x hours. X-ray diffraction and X-ray photoelectron spectroscopy analyses revealed that the alloying of Pd with pre-milled Mg50Ti50 was initiated after only a few minutes and was completed after 5h of milling. The maximum discharge capacity of the Mg50Ti50–3.3at.% Pd electrode increased significantly with the milling time (from 35mAhg−1 for 5min to 480mAhg−1 for 20h of milling). The exchange current density increased with the milling time and was directly related to the Pd surface concentration, suggesting that Pd plays a key role in facilitating the charge-transfer reaction. In contrast, the incorporation of Pd had a minor effect on the hydrogen diffusion coefficient. The electrochemical pressure-composition isotherms revealed a significant destabilization of the hydride as the milling time with Pd increased. No significant improvement in the hydrogen storage properties of Mg50Ti50–Pd electrodes was observed for Pd concentrations higher than 3.3at.%.
In the field of materials for lithium ion batteries, the lithium iron phosphate LiFePO4 has been proven for use as a positive electrode due to its good resistance to thermal degradation and overcharge, safety and low cost. The use of nanostructured materials would improve its efficiency. This work shows the results of the synthesis of nanostructured materials with functional properties for lithium batteries through aerosol techniques. The Spray Pyrolysis method allows synthesizing nanostructured particles with spherical geometry, not agglomerates, with narrow distribution of particle size and homogeneous composition in respect to a precursor solution. Experimental techniques were focused on the morphological (SEM and TEM), structural (XRD and HRTEM-SAED), chemical (EDS) and electrochemical characterization.
The surface of spinel LiMn2O4 is modified with different quantities of a Mn4+-rich phase prepared by a facile sol-gel method to improve electrochemical properties at elevated temperatures. Impurity-free and uniform morphologies for the LiMn2O4 particles are demonstrated from the X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The Mn4+-rich phase modified on the surface of the LiMn2O4 alleviates the dissolution of manganese in the electrolyte, thus improving the cycling performance and rate capability relative to the bare LiMn2O4. 1wt.%-modified LiMn2O4 delivers a capacity retention of 92.7% and a discharge capacity of 113.5mAhg−1 after 200 cycles at 1C and 25°C, compared with that of 83.1%, and 100.8mAhg−1 for the bare LiMn2O4. In addition, after 100 cycles, a capacity retention of 88.6% at 1C is achieved for 1wt.%-modified LiMn2O4 at 55°C, which is higher than the 76.0% for the bare LiMn2O4. Furthermore, this sample shows the best rate capability among all samples. The Mn4+-rich phase is an appropriate candidate for modifying surfaces to suppress dissolution of manganese, thereby improving the electrochemical properties of LiMn2O4.
Short-term mechanical circulatory devices (e.g. percutaneous cardiopulmonary bypass, percutaneous ventricular assist devices, etc.) can be initiated in emergency situations as a bridge to permanent implantation of ventricular assist devices in chronic end-stage heart failure. In the absence of first-person (patient) consent, presumed consent or surrogate consent should be used cautiously for the initiation of short-term mechanical circulatory devices in emergency situations as a bridge to permanent implantation of left ventricular assist devices. Future clinical studies of destination therapy with left ventricular assist devices should include measures of recipients' quality of end-of-life care and caregivers' burden.
Rechargeable metal-ion batteries are considered promising electric storage systems to meet the emerging demand from electric vehicles, electronics, and electric grids. Thus far, secondary Li-ion batteries (LIBs) have seen great advances in terms of both their energy and their power density. However, safety issues remain a challenge. Therefore, rechargeable Al-ion batteries (AIBs) with a highly reliable safety advantage and active electrochemical performances have gathered intensive attention. However, the common issue for these two metal-ion batteries is the lack of cathode materials. Many advanced electrode materials reported provide greatly enhanced electrochemical properties. However, their inherent disadvantages—such as complicated fabrication procedures, restricted manufacturing parameters, and the requirement of expensive instruments—limits their potential for further applications. In this work, we demonstrate the high electrochemical activity of the lanthanide element, Sm, towards storing charges when used in both LIBs and AIBs. Lanthanide elements are often overlooked; however, they generally have attractive electrochemical properties owing to their unpaired electrons. We employed starch as both a low-cost carbon source and as a three-dimensional support for Sm metal nanoparticles. The composite product is fabricated using a one-pot wet-chemical method, followed by a simultaneous carbonization process. As a result, highly improved electrochemical properties are obtained when it is used as a cathode material for both LIBs and AIBs when compared to bare starch-derived C. Our results may introduce a new avenue toward the design of high-performance electrode materials for LIBs and AIBs.
Surface modification of Li[Ni0.35Co0.3Mn0.35]O2 as a cathode material of lithium–ion batteries was carried out by hydrothermal treatment using lithium lanthanum titanate ([Li,La]TiO3). The modified surfaces were analyzed by morphology observation using transmission electron microscopy and by element investigation using X-ray photoelectron spectroscopy. It was thereupon found that the [Li,La]TiO3-coated layer formed by the surface modification played a definitive role in suppressing the solid electrolyte interface during repeated charge and discharge cycles. In addition, the thermal stability was enhanced by coated layer, resulting in an increase of the onset temperature to occur an exothermic reaction during thermal runaway.
Facile in-situ etching current collector prepares corresponding oxide or sulfide, which is directly used as faradic electrode material, supplying faster electron transportation and better connection, and thus displaying good supercapacitor performance. Here, we prepare CuxS via etching copper foam and investigate the influence of etching time on the morphology and electrochemical performance. The results show that compared with the nano-rod CuxS-1h/CF, nano-rod/wire CuxS-2h/CF and block/nanorod CuxS-4h/CF, the nano-rod/ribbon CuxS-3h/CF electrode exhibits the highest specific capacity (448.8Cg−1 at current density of 5mAcm−2). We fabricate asymmetric supercapacitor based on CuxS-3h/CF as positive electrode and AC as negative electrode to further evaluate the supercapacitor property and the device achieves a high energy density of 35 Wh kg−1 at power density of 266Wkg−1. Furthermore, the outstanding cycling stability of 88% capacitance retention after 5000 charge-discharge cycles more enable the CuxS-3h/CF become promising faradic electrode material.
Silicon oxycarbide (SiCO) is an amorphous molecular network of SiCO tetrahedra anchored to graphene-like carbon. The graphene forms a three dimensional cellular network with a domain size of ∼5 nm. Therefore nanometer thick films of SiCO grown on graphite may be expected to have unusual behavior. We grow these films on a bed of commercially available graphite fibers that serve the dual function of a current collector. The electrochemical behavior of the composite is measured as a function of the thickness of the SiCO films. Thick films approach the typical behavior of bulk SiCO (which has three times the capacity of graphite, but suffers from poor first cycle efficiency). However, films, approximately 100 nm thick, show high first cycle efficiency as well as high capacity. The composite performs better than the prediction from the rule-of-mixtures, which further substantiates the unusual behavior of the thin-film architecture. The Raman spectra of these thin films also differ from bulk SiCO. The development of thin graphite fibers, with a high surface to volume ratio that have the same capacity as the current graphite-powder technology, coupled with manufacturing of these thin-films by a liquid-polymer precursor based process, can propel these results toward commercialization.
We investigated (a) the fit and structural equivalence of Holland’s model of six vocational personality types in a sample of South African men (n = 139) and women (n = 268) using the South African Career Interest Inventory, and (b) mean score differences for men and women on these types. The results supported the fit and structural similarity of Holland’s model of vocational personality types for men and women but showed that the model fit the data better for women. The largest differences in the mean scores occurred on the Realistic scale. Implications of the results are presented.
Publisher Summary This chapter discusses applications of an open source desktop. The major application of open source desktops are graphical desktop, web browsers, office programs, professional applications (graphics, database front ends, Web designers), and personal applications (media players, games). A complete open source desktop with applications can be easily installed and demonstrated on a typical personal computer using Linux. These desktops are attractive, powerful, and easy to learn from scratch as Windows. Such desktops can be significantly less expensive than closed code systems, since they can save the operating system cost plus the cost of applications such as Microsoft Office. There is a possibility to build a desktop on Windows, where all the applications are open source. In situations where the operating system is already installed, such as on home computers, there is no savings to replace it with Linux, but there are huge cost savings from replacing applications such as Office with open source.
An innovative process was optimized to recover Co from portable Lithium Ion Batteries (LIB). Pilot scale physical pretreatment was performed to recover electrodic powder from LIB. Co was extracted from electrodic powder by a hydrometallurgical process including the following main stages: leaching (by acid reducing conditions), primary purification (by precipitation of metal impurities), solvent extraction with D2EPHA (for removal of metal impurities), solvent extraction with Cyanex 272 (for separation of cobalt from nickel), cobalt recovery (by precipitation of cobalt carbonate). Tests were separately performed to identify the optimal operating conditions for precipitation (pH 3.8 or 4.8), solvent extraction with D2EHPA (pH 3.8; Mn/D2EHPA=4; 10% TBP; two sequential extractive steps) and solvent extraction with Cyanex 272 (pH 3.8; Cyanex/Cobalt=4, 10% TBP, one extractive step). The sequence of optimized process stages was finally performed to obtain cobalt carbonate. Products with different degree of purity were obtained depending on the performed purification steps (precipitation with or without solvent extraction). 95% purity was achieved by implementation of the process including the solvent extraction stages with D2EHPA and Cyanex 272 and final washing for sodium removal.
This article deals with the properties of high-voltage cathode material LiNi0.5Mn1.5O4 synthesized by a solid-state reaction method and the influence of doping this material by molybdenum. The samples – LiMo x + y Ni0.5 - x Mn1.5 - y O4 with different Mo contents (x = 0.00, 0.05, y = 0.00, 0.05) were successfully synthesized by two step annealing process and they were then investigated by SEM, EDS spectroscopy, thermo gravimetric analysis, cyclic voltammetry and charge–discharge tests at different loads and high temperature in lithium-ion cells with metal lithium as a counter electrode. Results showed that the initial discharge capacity and capacity during high temperature cycling of the LiMox + yNi0.5 - xMn1.5 - yO4 cathode were improved with addition of Mo when x = 0.05. Thermal analysis results suggested that the Mo doping slightly improved the stability of the crystal structure of the LiNi0.5Mn1.5O4 cathode which leads to an improved stability during high temperature galvanostatic cycling.