batterydata/paper-abstracts huggingface dataset:
Zn metal with high theoretical capacity (820mAhg−1), environmental-friendly properties and low cost is very competitive to be as an anode for aqueous batteries. However, uncontrollable growth of dendritic zinc in these batteries during plating/stripping process of zinc ions not only leads to a low Coulombic efficiency but also brings safety hazards, which have obstructed the application of secondary Zn-based batteries. Here we use high conductive carbon fiber-graphite felt (GF) as collector and electrodeposit zinc under constant voltage to fabricate a self-supported Zn@GF negative electrode. The graphite felt provides this anode larger electroactive area to transport electrons faster and loads zinc in a more event way, thus preluding the zinc plating in several specific directions. This composite anode offers an efficient solution to get a dendrite-free cycling behavior of zinc-based batteries and might be promising in advanced aqueous batteries for large-scale energy storage.
Long-term episodic memory deficits in Alzheimer's disease (AD) are well characterised but, until recently, short-term memory (STM) function has attracted far less attention. We employed a recently-developed, delayed reproduction task which requires participants to reproduce precisely the remembered location of items they had seen only seconds previously. This paradigm provides not only a continuous measure of localization error in memory, but also an index of relational binding by determining the frequency with which an object is misplaced to the location of one of the other items held in memory. Such binding errors in STM have previously been found on this task to be sensitive to medial temporal lobe (MTL) damage in focal lesion cases. Twenty individuals with pathological mutations in presenilin 1 or amyloid precursor protein genes for familial Alzheimer's disease (FAD) were tested together with 62 healthy controls. Participants were assessed using the delayed reproduction memory task, a standard neuropsychological battery and structural MRI. Overall, FAD mutation carriers were worse than controls for object identity as well as in gross localization memory performance. Moreover, they showed greater misbinding of object identity and location than healthy controls. Thus they would often mislocalize a correctly-identified item to the location of one of the other items held in memory. Significantly, asymptomatic gene carriers – who performed similarly to healthy controls on standard neuropsychological tests – had a specific impairment in object-location binding, despite intact memory for object identity and location. Consistent with the hypothesis that the hippocampus is critically involved in relational binding regardless of memory duration, decreased hippocampal volume across FAD participants was significantly associated with deficits in object-location binding but not with recall precision for object identity or localization. Object-location binding may therefore provide a sensitive cognitive biomarker for MTL dysfunction in a range of diseases including AD.
Regulators generally discourage bank CEOs also holding the role of board Chairman, as this governance structure can hinder independent decision-making and effective risk oversight. This study examines the issue of CEO Duality, identifying a positive relation to greater risk-taking across a battery of sensitivity tests. In further analysis, the study controls for differences in supervisory monitoring levels to examine its impact. Banks led by CEO Chairmen which are subject to lower levels of supervision continue to report a robust association to risk-taking, as before. However, this association dissipates for banks which are subject to heightened supervisory monitoring. These findings indicate that agency costs related to Duality may be moderated by greater regulation. This paper weighs-in on the controversy relating to a single contentious governance structure (i.e., CEO Duality), thus informing boards, regulators and researchers of the need to consider the overall interplay of monitoring mechanisms.
Macromolecular ionomer solutions exhibiting macroscopic properties that change in response to temperature are referred to as thermally responsive polymer electrolytes (RPEs). Such materials provide a means to control electrochemical systems using an external stimulus that affects the polymer phase behavior and electrolyte properties. RPEs were synthesized with N-isopropylacrylamide, which governs the thermal properties, and varying fractions of acrylic acid, which provides ionic properties. These polymers undergo a thermally activated phase separation in aqueous solutions at a given temperature, thereby altering the ionic strength, pH, and conductivity of the electrolyte solution. In this article, we demonstrate how the molecular properties of RPEs, specifically the ionic composition, influence the temperature-dependent electrolyte properties and the extent to which these electrolytes can control the activity of redox electrodes. Materials with high ionic content provide the highest room temperature ion conductivity and redox activity; however, RPEs with low ionic content provide the highest “on–off” ratio in electrochemical activity at elevated temperatures.
High energy density lithium-air batteries are ideal storage systems for future transportation like electric vehicles. The theoretical energy density of lithium-oxygen batteries is more than ten times greater than the energy density of lithium-ion batteries which are currently used in electric vehicles. In spite of high energy density of lithium-oxygen batteries, there are several challenges that need to be overcome for development of these batteries. In the lithium-air batteries, oxygen crosses the separator to the anode/separator interface and reacts with the lithium anode known as oxygen crossover which is one the main challenges in lithium-air batteries. In the present study, this phenomenon, oxygen crossover, is investigated by Arrhenius equation for simulation of reaction kinetics. A mathematical model based on Newman porous electrode theory is implemented to simulate the cycling performance. The effect of diffusion coefficient, oxygen solubility, applied current density and oxygen crossover reaction kinetics parameter on the performance of the battery are investigated. The results show that with the reduction of diffusion coefficient and oxygen solubility in the electrolyte, the cycling performance is enhanced. But the increase in these two parameters leads to decay of efficiency and specific capacity. On the other hand, change in kinetics parameters have the same effects on the efficiency and cycling performance of the battery. Therefore, the key point in the performance enhancement is making barrier in the oxygen crossover reaction path.
Co, Mn and Mg co-doped lithium nickel oxides of the nominal composition LiNi0.9Co0.1−x [Mn1/2Mg1/2] x O2 (x =0.00, 0.02, 0.04, 0.06) are synthesized by a co-precipitation technique and solid state route. XPS results reveal that the oxidation states of Ni, Co, Mn and Mg are +3, +3, +4 and +2, respectively. An ordered α-NaFeO2 rock salt structure with R − 3 ¯ m symmetry has been confirmed by XRD. The cation mixing of Li/Ni and occupation of Mg ions have been analyzed by Rieveld refinement. Mg ions distribute between 3b and 3a sites in the crystal. Meanwhile a substantial reduction of cation mixing of Li–Ni has been confirmed by Mn–Mg substitution. Better cycling performance is observed in the compound with high Mn–Mg content compared with LiNi0.9Co0.1O2. Mn–Mg substitution for Co has been shown to suppress the increase of the cell impedance during cycles effectively.
Objective: To apply new psychometric criteria for DSM-IV Mild Neurocognitive Disorder (MND) to a sample of patients who have been treated for brain tumors. Design: Quasi-Experimental. Setting: Healthy adults were tested in the community and patients with brain tumors were tested as outpatients at the hospital or university. Participants: Psychometric criteria for MND were developed on a sample of 1,261 healthy adults between the ages of 18 and 79 from the Neuropsychological Assessment Battery (NAB) standardization sample. The clinical sample was 33 patients evaluated following their treatment for a primary or metastatic brain tumor. Interventions: Not applicable. Main Outcome Measures: An abbreviated version of the NAB, administered in approximately 2 hours, was used. This battery included 5 tests measuring attention and speed, 2 measuring language, 3 measuring learning and memory, two measuring spatial abilities, and 3 measuring executive functioning. All were also administered the Reynolds Intellectual Screening Test. Results: Criteria for possible and probable MND were derived by calculating the base rates of low scores in each domain for the healthy adults using several cutoffs. The criteria were stratified by level of intellectual ability. When applied to the patients treated for brain tumors, the classification breakdown was as follows: Probable MND=54.5%, Possible MND=36.4%, and Broadly Normal=9.1%. Conclusions: These new psychometric criteria for MND have low false positive rates in healthy adults and appeared to accurately identify impairment in patients treated for brain tumors.
Novel plasticized polymer electrolytes were synthesized with poly(N,N-dimethylamino-ethyl-methacrylate) (PDMAEMA), polyethylene oxide (PEO), LiTFSI as a salt, tetraethylene glycol dimethyl ether (tetraglyme), EC/PC and DEP as plasticizers. The ionic conductivity of various compositions of polymer electrolytes was investigated as a function of temperature, various concentrations of LiTFSI, plasticizers and various ratio of PDMAEMA/PEO. The ionic conductivity of PDMAEMA/PEO/LiTFSI (1.5molkg−1) with DEP as a plasticizer (1.5×10−4 Scm−1) exhibited lower than PDMAEMA/PEO/LiTFSI (1.2molkg−1)/tetraglyme (5.24×10−4 Scm−1) and PDMAEMA/PEO/LiTFSI (1.5molkg−1)/EC+PC (2.1×10−4 Scm−1). As increasing the PDMAEMA concentration up to 13.3%, the ionic conductivity was decreased rapidly. As increasing the PDMAEMA concentration the ionic conductivity was decreased due to high viscosity and some interactions reducing ion pairing. These plasticized polymer electrolytes were characterized by impedance spectroscopy and DSC.
Valve regulated lead acid (VRLA) battery constitutes towards the largest part of the worldwide secondary battery market share. Indisputably, absorptive glass mat (AGM) is a key component in a VRLA battery that is often engineered utilizing the synergy that exists between fiber and structural parameters. Over the past few decades, a considerable progress has been made in designing and tailoring the AGM separators but often limited by ‘trial-and-error’ approach. Here in, we present a comprehensive review that specifically targets the design of AGM separators by bridging a gap between fiber-structure-property relationships. The critical review on various experimental and theoretical studies aims to present a template for ‘designer’ AGM separator to fulfill the demands of any application of VRLA batteries. The review surveys important functions and various properties of AGM separators, which have been related with a key set of fiber and structural parameters. Several challenges presented in the form of failure modes of the VRLA battery can be overcome by leveraging the synergy between key set of fiber and structural parameters. This review also highlights the structural commonalities between AGM separators and the other nonwoven materials. This opens up an opportunity to utilize the existing theoretical models of nonwovens to the AGM separators.
Single-atom site catalysts (SACs) have received considerable attention for electrocatalytic applications, owing to their maximum atom-utilization efficiency, well-identified active centers, and tunable supports. Carbon-supported SACs have been widely applied in electrocatalysis, and their progress has been intensively reviewed. Non-carbon-supported SACs have drawn ever-increasing attention recently, and are emerging as an indispensable class of SACs. This review comprehensively summarizes the recent exciting progress on the non-carbon-supported SACs and their applications in electrocatalytic reactions. Eight types of non-carbon-supported SACs are firstly categorized to show their diversity. Subsequently, the anchoring and stabilization mechanisms for each type of non-carbon-supported SACs are systematically unraveled. Furthermore, the advanced characterization techniques for identifying and monitoring the atomic structure of SACs are highlighted. Thereafter, the advances of non-carbon-supported SACs for electrochemical energy conversion are discussed, which emphasizes their applications in the hydrogen evolution reaction, the oxygen evolution reaction, the oxygen reduction reaction, the N2 reduction reaction, and the CO2 reduction reaction. Finally, perspective insights into the current challenges and the future prospects for non-carbon-supported SACs are provided.
Impedance spectra of a high energy lithium-ion battery (graphite vs. NMC) are investigated in detail, using the distribution of relaxation times (DRT) and complementary methods. Two predominant processes are found, one at lower frequencies and one at moderate frequencies. By investigating impedance spectra of corresponding half-cells (graphite vs. Li and NMC vs. Li), it is found that the process at lower frequencies can clearly be assigned to the NMC's charge transfer. Further, it is assumed that the process at moderate frequencies is correlated to the graphite's solid electrolyte interphase (SEI). However, the relevant frequency-range of the anode half-cell is seemingly overshadowed by the lithium counter-electrode and thus cannot be investigated properly. To investigate this issue, symmetrical lithium cells are build and their impedance spectra are investigated as well. Indeed, the lithium's main-process occurs at the presumed frequencies. Eventually, a combination of several measurements and analyses show that the process at moderate frequencies is correlated to the graphite's SEI. Among these are i) an investigation of a calendric aged commercial cell and its corresponding half-cells and ii) a differential regression analysis (DRA), which is established in this work and proved to be a powerful analysis-tool.
A gel polymer electrolyte (GPE) was successfully prepared by means of an in situ cross-linking reaction of poly(2-vinylpyridine-co-styrene) and oligo(ethylene oxide) with epoxide functional groups at 65°C without using a polymerization initiator. A stable gel polymer electrolyte could be obtained by adding only 1% of a polymer gelator. The ionic conductivity of the GPE containing 99wt% of liquid electrolyte was measured to be ca. 10−2 S/cm at the ambient temperature. The ionic conductivity of the resulting GPE was comparable to that of a pure liquid electrolyte. The electrochemical stability window of the prepared gel polymer electrolytes was measured to be 5.2V. The test cell carried a discharge capacity of 133.2mAh/g at 0.1C and showed good cycling performance with negligible capacity fading after the 200th cycle, maintaining 99.5% coulombic efficiency throughout 200 cycles. The resulting gel polymer electrolyte prepared by in situ thermal cross-linking without a polymerization initiator holds promise for application to on the high power lithium-ion polymer batteries.
We report on the facile synthesis of porous silicon structure via magnesiothermic reduction followed by coating of the surface with TiSi2. These modifications not only showed significant promise in overcoming the drastic volume change during charge and discharge cycles but also in improving the relatively low conductivity of silicon. The synthesized porous structure with a highly electrically conductive coating layer significantly enhanced the electrochemical performance in terms of cyclic stability and rate capability. The TiSi2 coating layer, which has good electrical conductivity and physical strength, enhances the conductivity and maintains the Si structure during cycling. This combination of porous structure via magnesiothermic reduction and highly conductive TiSi2 coating provides a synergistic effect, which can be seen in the improvements in electrochemical performance. This synthesis demonstrates a promising method for producing high capacity anode materials for next generation LIBs.
It is a core task to find solutions to suppress the “shuttle effect” of polysulfides and improve high rate capability at the sulfur cathode of lithium sulfur batteries. Herein we first time propose a concept of multileveled blocking “dams” to suppress the diffusion of polysulfides. We report a facile and effective strategy to construct multidimensional conductive carbon hosts for accommodation of active sulfur. Multidimensional ternary carbon networks (MTCNs) with 0D nanospheres, 1D nanotubes and 2D nanoflakes are organically combined together to provide multileveled conductive channels to reserve active sulfur and promote stable sustained reactions. In the light of enhanced conductivity and multileveled blocking “dams” for polysulfides, the designed MTCNs/S cathode has been demonstrated with noticeable improvement in discharge capacity (1472 mAh g−1 at 0.l C) and long-term cycling stability (65% retention at 5.0 C after 500 cycles). Our research may provide a new insight in the gradient blocking of polysulfides with the help of multidimensional carbon networks.
The hydrodynamics of tree islands during the growth of newly planted trees has been found to be influenced by both vegetation biomass and geologic conditions. From July 2007 through June 2009, groundwater and surface-water levels were monitored on eight recently planted tree islands at the Loxahatchee Impoundment Landscape Assessment (LILA) facility in Boynton Beach, Florida, USA. Over the 2-year study, stand development coincided with the development of a water-table depression in the center of each of the islands that was bounded by a hydraulic divide along the edges. The water-table depression was greater in islands composed of limestone as compared to those composed of peat. The findings of this study suggest that groundwater evapotranspiration by trees on tree islands creates complex hydrologic interactions between the shallow groundwater in tree islands and the surrounding surface water and groundwater bodies.
Since the first description of sound-evoked short-latency myogenic reflexes recorded from neck muscles, vestibular evoked myogenic potentials (VEMPs) have become an important part of the neuro-otological test battery. VEMPs provide a means of assessing otolith function: stimulation of the vestibular system with air-conducted sound activates predominantly saccular afferents, while bone-conducted vibration activates a combination of saccular and utricular afferents. The conventional method for recording the VEMP involves measuring electromyographic (EMG) activity from surface electrodes placed over the tonically-activated sternocleidomastoid (SCM) muscles. The “cervical VEMP” (cVEMP) is thus a manifestation of the vestibulo-collic reflex. However, recent research has shown that VEMPs can also be recorded from the extraocular muscles using surface electrodes placed near the eyes. These “ocular VEMPs” (oVEMPs) are a manifestation of the vestibulo-ocular reflex. Here we describe the historical development and neurophysiological properties of the cVEMP and oVEMP and provide recommendations for recording both reflexes. While the cVEMP has documented diagnostic utility in many disorders affecting vestibular function, relatively little is known as yet about the clinical value of the oVEMP. We therefore outline the known cVEMP and oVEMP characteristics in common central and peripheral disorders encountered in neuro-otology clinics.
During the Pittsburgh Air Quality Study (PAQS), July 2001–September 2002, three co-located instruments analyzed the composition of ambient particulate matter (PM): (1) A single particle mass spectrometer, RSMS-3, was deployed to obtain high-temporal-resolution measurements of single particle size (>1.1μm) and composition which were correlated with meteorological data to identify sources; (2) PM2.5 and PM10 were collected on cellulose filters using high-volume (hi-vol) samplers, followed by microwave-assisted digestion and analysis by inductively coupled plasma–mass spectrometry (ICP–MS). Positive matrix factorization (PMF) was used to identify possible source categories; and (3) a micro-orifice uniform-deposit impactor (MOUDI) obtained size-distributed samples of PM. Several days of MOUDI filters were selected for microwave-assisted digestion and analysis by ICP–MS. In this paper, sources identified using the single particle data were compared to the PMF results for the hi-vol/ICP–MS data. The strengths of each method were combined to hypothesize the most likely sources of various elements in ambient PM in Pittsburgh. In the final results, Mo and Cr are attributed to local specialty steel facilities; Fe, Mn, Zn, and K are attributed to a steel mill SE of the monitoring station; internally mixed Pb-containing particles are attributed to a major source to the NW; and Ga is attributed to coal combustion sources to the NW. There is a notable lack of oil combustion sources. The MOUDI data were used to resolve discrepancies between the single particle and hi-vol/ICP–MS data concerning the detection of Ti and Se. The hi-vol data showed appreciable Ti and Se masses, but RSMS-3 was unable to detect significant numbers of Ti-containing particles because of their large size, while we hypothesize that the volatility of Se caused it to be distributed more evenly over all emitted particles such that the amount of Se in any individual particle is below the limit of detection.
Metal nanoclusters exhibit unusually high catalytic activity toward oxygen reduction reaction (ORR) due to their small size and unique electronic structures. However, controllable synthesis of stable metal nanoclusters is a challenge, and the durability of metal clusters suffers from the deficiency of dissolution, aggregation, and sintering during catalysis reactions. Herein, silver nanoclusters (AgNCs) (diameter < 2 nm) were controllably electrochemically reduced on nitrogen-doped graphene (NG) using effective single-stranded oligonucleotide sequences (ssDNA) as the performed template in absence of any other reluctant. The ssDNA is significant for providing AgNCs with growth template and anchoring the cluster on graphene surface. The strong interaction between the AgNCs, ssDNA and NG renders the as-synthesized AgNCs/NG composite with high-performance onset potential, half-wave potential and mass activity for ORR approaching to commercial Pt/C catalyst, and remarkably superior ORR performance than NG and Ag nanoparticle/NG. Importantly, the AgNCs/NG composite shows excellent methanol tolerance and accelerated electrochemical stability (8000 cycles), which is vital in high performance fuel cells, batteries and nanodevices.
RFID (Radio Frequency Identification) technology is expected to play a vital role in the healthcare arena, especially in times when cost containments are at the top of the priorities of healthcare management authorities. Medical equipment represents a significant share of yearly healthcare operational costs; hence, ensuring an effective and efficient management of such key assets is critical to promptly and reliably deliver a diversity of clinical services at the patient bedside. Empirical evidence from a phased-out RFID implementation in one European hospital demonstrates that RFID has the potential to transform asset management by improving inventory management, enhancing asset utilization, increasing staff productivity, improving care services, enhancing maintenance compliance, and increasing information visibility. Most importantly, RFID allows the emergence of intelligent asset management processes, which is, undoubtedly, the most important benefit that could be derived from the RFID system. Results show that the added intelligence can be rather basic (auto-status change) or a bit more advanced (personalized automatic triggers). More importantly, adding intelligence improves planning and decision-making processes.