batterydata/paper-abstracts huggingface dataset:
An analysis is presented of the losses occurring in a kW-class vanadium redox flow battery due to species crossover, shunt currents, hydraulic pressure drops and pumping, in addition to cell overpotentials. The study was developed on a 9 kW/27 kW h test facility that includes a stack consisting of a 40 cells with 600-cm2 cross sectional area and two 550 L electrolyte tanks. The analysis was carried out combining experimental data and model results. The losses were evaluated as functions of the solution flow rates at stack currents of 30 A, 50 A and 70 A. Charge-discharge cycles performed at a constant flow factor equal to 8 and thus at variable flow rate were analyzed. Results show that shunt currents have a tenfold to twentyfold higher effect than hydraulic pressure drop inside the stack. As regards cell membranes, it has been found that, in terms of efficiency, the ion conductivity (i.e. cell overpotentials) counts more than species diffusivity (i.e. crossover). Moreover, it was found that pumps and their motors can affect significantly the efficiency of a kW-class vanadium redox flow battery system.
Navigated freehand bone cutting (NFC) is introduced as a concept to eliminate alignment jigs and facilitate smaller arthroplasty incisions. We compare experimental cuts with this technique to conventional jigs. Using an in-house–built computer-aided orthopedic surgery system directly navigating a bone saw, users with different levels of surgical skills were timed performing full sets of distal femoral total knee arthroplasty cuts with jigs and with NFC. The cut surfaces were digitized to measure roughness and 3-dimensional translational/rotational errors. Navigated freehand cutting was 15% faster and produced 200% rougher surfaces than jigs, although its worst peaks/valleys were less than 1.2 mm. Implant fit/looseness, assessed by special navigated tools, was similar; but alignment was 400% better with NFC. Even at its infancy, NFC appears not to prohibitively compromise time and quality of cutting. Without requiring jigs, it has potential for radically less invasive total knee arthroplasty surgery.
“Life is a pure flame, and we live by an invisible fire within us.” THOMAS BROWNE.
Accelerated cycle life testing of lithium-ion batteries is conducted as a means to assess whether a battery will meet its life cycle requirements. This paper presents a study to identify optimal accelerated cycle testing conditions for LiCoO2-graphite cells. A full factorial design of experiment with three stress factors—ambient temperature (10 °C, 25 °C, 45 °C, 60 °C), discharge current rate (C-rate, 0.7C, 1C, 2C), and charge cut-off C-rate (C/5, C/40)—is used to study the effects of these stress factors on battery capacity fade and to obtain the data necessary for decision making. An empirical accelerated degradation model is then developed to capture the characteristics of the two-stage capacity degradation process, along with an accelerated test planning approach.
Nanoparticle of Li(Ni1/3Co1/3Mn1/3)O2 with size smaller than 40nm was obtained by non-aqueous system co-precipitation method. The particle morphology and crystal plane orientation were observed by TEM and HRTEM. Electrochemical properties of this nanostructued material were studied with experiment cells. The results show that the material has high capacity of 160mAhg−1 and excellent rate capability for charge and discharge. For the 50C and 100C rate, its capacity remains above 100mAhg−1 after tens of cycles.
The fuel cell (FC), as a clean and high-efficiency device, has drawn a great deal of attention in terms of both fundamentals and applications. However, the high cost and scarcity of the requisite platinum catalyst as well as a sluggish oxygen reduction reaction (ORR) at the cathode in FC have become the greatest barrier to large-scale industrial application of FC. The development of novel non-precious metal catalysts (NPMC) with excellent electrocatalytic performance has been viewed as an important strategy to promote the development of FC. Recent studies have proven that metal free carbon materials doped with heteroatom (e.g. N, B, P, S or Se) have also shown striking electrocatalytic performance for ORR and become an important category of potential candidates for replacing Pt-based catalysts. This review summarizes recent achievements in heteroatom doped carbon materials as ORR catalysts, and will be beneficial to future development of other novel low-cost NPMCs with high activities and long lifetimes for practical FC applications.
In this report, the lithium solvation behavior of two series of glyme-based electrolytes, with lithium trifluoromethanesulfonate (LiTf) or lithium-bis-(trifluormethanesulfonyl)-imide (LiTFSI) in six glymes with different chain length, is characterized using natural abundance oxygen-17 (17O) NMR spectroscopy. The effect of salt addition on chemical shift is observed by comparing the 17O NMR spectra of electrolytes and their corresponding neat solvents. The study reveals a more pronounced effect of the salt addition on the chemical shift of ether oxygens compared to terminal oxygens of glymes, thus suggesting a preferential coordination of Li+ with the ether oxygens. The 17O NMR data exhibit decreasing chemical shift changes with increasing chain length of glymes due to the increased number of ether oxygens coordinating each Li+ in the electrolytes. In addition, the trend of anion oxygen chemical shift, particularly for Tf− anion, suggests an effect of the chain length on the ion association degree. The results illustrate the sensitivity of 17O NMR to subtle changes in the ion-solvent and ion–ion interactions.
In this work we investigate by impedance spectroscopy the characteristics of a film formed on the surface of Sn electrodes when cycled in a lithium cell. We show that this film is formed by electrolyte decomposition catalyzed by the tin surface and that its characteristics depend upon cycling rate as reported in the literature. By the infrared analysis we study the chemical characteristic of mentioned film. By reporting the cycling response of a complete lithium-ion battery using a Sn anode coupled with a LiNi0.5Mn1.5O4 cathode, we show that the interfacial film may indeed influence the response of the batteries using conventional, tin-based anodes.
Kernel smoothing of spatial point data can often be improved using an adaptive, spatially varying bandwidth instead of a fixed bandwidth. However, computation with a varying bandwidth is much more demanding, especially when edge correction and bandwidth selection are involved. This paper proposes several new computational methods for adaptive kernel estimation from spatial point pattern data. A key idea is that a variable-bandwidth kernel estimator for d-dimensional spatial data can be represented as a slice of a fixed-bandwidth kernel estimator in
This chapter provides an overview of the codes, regulations, and standards regarding those persons who work with asbestos. It provides lists of products allowed to contain asbestos and those that have been banned or phased out. Keywords: American National Standards Institute, American Society for Testing and Materials, Asbestos Hazard Emergency Response Act, asbestos-containing product, emission standard, National Emission Standard for Hazardous Air Pollutants, occupational exposure, training requirement
The benefits of the conformal coating of polyethylene oxide (PEO)-based polymer electrolyte by the electropolymerization technique on titania nanotubes (TiO2nts) are highlighted. Due to the presence of polymer electrolyte coating the nanotubes, the capacity of the half cell is improved by 45% at 1 C compared to bare TiO2nts. The polymer-coated TiO2nts in the full cell deliver an average capacity of ∼30 μA h cm−2 (120 mA h g−1) with LiNi0.5M1.5O4, ∼25 μA h cm−2 (100 mA h g−1) with LiFePO4 and ∼23 μA h cm−2 (90 mA h g−1) with LiCoO2, respectively during 50 cycles.
Future increases of energy density of lithium-ion batteries require a systematic optimization of electrode structure and the related production process. Such optimization is facilitated by electrochemical models which predict cell performance with good accuracy. In this work, classic relations of structure to model parameters in the classical Doyle-Newman electrode model are replaced to improve the prediction accuracy of the model regarding electrode structure effects. Therefor, a 3D micro structure model is used to derive effective electrode property relations for ionic and electric conductivity, which are then used in the computationally efficient P2D framework of the Doyle-Newman model. Simulations show clearly the transition from an electron transport limited to an ion transport limited electrode performance with increasing compression ratio. Integrating the derived algebraic structure-model parameter relations into the electrochemical model allows a higher accuracy in predicting the optimal porosity of the experimental data compared to the classical P2D model.
Inheritance of the human ϵ4 allele of the apolipoprotein (apo) E gene (APOE) significantly increases the risk of developing Alzheimer’s disease (AD), in addition to adversely influencing clinical outcomes of other neurologic diseases. While apoE isoforms differentially interact with amyloid β (Aβ), a pleiotropic neurotoxin key to AD etiology, more recent work has focused on immune regulation in AD pathogenesis and on the mechanisms of innate immunomodulatory effects associated with inheritance of different APOE alleles. APOE genotype modulates expression of proximal genes including APOC1, which encodes a small apolipoprotein that is associated with Aβ plaques. Here we tested the hypothesis that APOE-genotype dependent innate immunomodulation may be mediated in part by apoC-I.
In the present study, polypyrrole-carbon black (Ppy-C) composite is synthesized via in situ chemical polymerization method and then Pt nanoparticles are deposited on the surface of Ppy-C, where tartaric acid is employed as both a reductant and a stabilizer for Pt nanoparticles. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) indicate that Pt nanoparticles have a higher dispersion and smaller particle size (∼2.3nm) on Ppy-C composite than that on carbon black. Electrochemical measurements show that Pt/Ppy-C catalyst Exhibits 60% higher electrocatalytic activity towards methanol oxidation than Pt/C. X-ray photoelectron spectroscopy (XPS) characterization indicates Pt4f binding energy in Pt/Ppy-C is shifted by+0.2eV as compared with that in Pt/C, while N 1s binding energy in Pt/Ppy-C shifted by −0.5eV as compared with that in Ppy-C composite. The Pt-pyridinic nitrogen sites suppress the posioning CO adsorption on Pt nanoparticles and facilitate the methanol electrocatalytic oxidation. This work is important for the understanding of the role of Ppy in the fuel cell electrocatalyst, and the development of advanced catalysts for methanol oxidation.
There are few publications about quantitative measurement of capacitance in Li-ion cells which in addition distinguish between pure electrostatic double-layer capacitance and capacitance caused by Faradaic effects. The measurement techniques electrochemical impedance spectroscopy, pulse current measurement and cyclic voltammetry are used to analyze a conventional high-energy Li-ion cell consisting of Li-nickel-manganese-cobalt-oxide Li1−x Ni0.3Co0.3Mn0.3O2 as positive and graphite Li x C y as negative electrode material. The results show the highest capacitance of the full cell at a frequency of 10 mHz at approximately 40% state-of-charge (SOC), which is equal to the cell voltage around 3.64 V, attributed to intercalation capacitance. Toward higher frequencies around 1 Hz, the capacitance increases with SOC. The measurements reveal that the positive electrode mainly causes this sensitivity of capacitance on SOC or electrode potential at around 1 Hz.
TiO2 of various morphologies was synthesized by a hydrothermal method. Among them, urchin-like TiO2 exhibited the largest BET [Brunauer–Emmett–Teller] specific surface area. In this paper, the full-cell was fabricated using Urchin-like TiO2 as negative electrode and the activated carbon as positive electrode and measured electrochemical properties for cell balancing of cylindrical hybrid supercapacitors. The hybrid supercapacitor using urchin-like TiO2 with a large specific surface area had a discharge-specific capacitance of 61.1Fg−1 and excellent cycle life. Also, the hybrid supercapacitor with an urchin-like TiO2 negative electrode showed a maximum power density of 12224.356Wkg−1 at an energy density of 10.134Whkg−1 and maximum energy density of 50.648Whkg−1 at a power density of 194.412Wkg−1. Thus, urchin-like TiO2 showed potential as a material for the negative electrode of hybrid supercapacitors.
Simultaneous measurements of oxygen and heat rates are useful for the determination of thermodynamics and kinetics of metabolic and chemical reactions involving oxygen. Optrodes have not previously been used to measure oxygen inside calorimetric vessels. The optrode used in this study produces <2μW and can be used to make measurements in both gaseous and aqueous systems. An external syringe injection of air was used to calibrate the optrode, and zinc–air batteries were used to evaluate the system. Data on maple leaf buds were collected to demonstrate application to respiration measurements.
In this manuscript, we demonstrated a facile route for the controllable design of “Fluorine (F)-doped carbon” (C/F)-treated TiO2 hollow spheres with mesoporous shells (MHTO-C/F). The fabrication of this distinct mesoporous hollow structures and the C/F coating could effectively improve the electrolyte permeability and architectural stability, as well as electrical conductivity and lithium ion mobility. As anticipated, MHTO-C/F has several remarkable electrochemical properties, such as a high specific reversible capacity of 252mAhg−1, outstanding cycling stability of more than 210mAhg−1 after 100 cycles at 0.5C, and good rate performance of around 123mAhg−1 at 5C (1C=168mAg−1). These properties are highly beneficial for lithium storage.
Publisher Summary The primary goal of this chapter is to promote an awareness of the scope and breadth of the scientific discipline underlying questionnaire and survey development that should guide the design and analysis phases of the research study. The following study presents measurement, design, and analysis issues with which all clinical investigators should be familiar prior to employing patient surveys and questionnaires in their research studies. Observing or asking patients how they feel and function can also obtain certain types of information required for testing clinical research hypotheses. For many areas of clinical investigation the interpretation of research results derived solely from clinical and laboratory data can be enhanced by information that reflects the patient's perspective of a disease condition or state of health. In particular, studies evaluating the risks and benefits of new therapies should always include a description of benefits from the patient's perspective. The purpose of this chapter is to describe the scientific framework, as well as the more commonly used methodological issues and techniques, for collecting data from clinical research subjects using questionnaires and surveys. The use of questionnaires and survey instruments can greatly expand the types of data that can be obtained from clinical research. The purpose of a questionnaire is to better understand how patients feel and behave as a group, usually after some form of intervention or therapy.
The growing use of variable energy sources is pushing the need for energy storage. With Pumped Hydro Energy Storage (PHES) representing most of the world’s energy storage installed capacity and given its maturity and simplicity, the question stands as to whether this technology could be used on a smaller scale, namely in buildings. In this paper, the feasibility of such an installation is analysed by modelling each one of its components and applying it to several installation scenarios. Proposed and existing installations are also reviewed, including a first-time analysis of an installation in France, which is presumably the only existing building with an integrated PHES system. It was found that the economies of scale that render large PHES installations competitive are not present in small installations. This limitation, associated to other important disadvantages, such as the large volume required, seem to point out PHES as an ill-suited solution for energy storage in buildings, an important finding for building design and energy policy. Nevertheless, if synergies with existing reservoirs could be found (for example for a building on a riverside), costs could be significantly lowered. Further research on possible synergies with other building systems as well as a life-cycle assessment analysis are recommended.
Electrochemical and rheological properties are reported of composite polymer electrolytes (CPEs) consisting of dual-functionalized fumed silica with methacrylate and octyl groups+low-molecular weight poly(ethylene glycol) dimethyl ether (PEGdm)+lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, lithium imide)+butyl methacrylate (BMA). The role of butyl methacrylate, which aids in formation of a crosslinked network by tethering adjacent fumed silica particles, on rheology and electrochemistry is examined together with the effects of fumed silica surface group, fumed silica weight percent, salt concentration, and solvent molecular weight. Chemical crosslinking of the fumed silica with 20% BMA shows a substantial increase in the elastic modulus of the system and a transition from a liquid-like/flocculated state to an elastic network. In contrast, no change in lithium transference number and only a modest decrease (factor of 2) on conductivity of the CPE are observed, indicating that a crosslinked silica network has minimal effect on the mechanism of ionic transport. These trends suggest that the chemical crosslinks occur on a microscopic scale, as opposed to a molecular scale, between adjacent silica particles and therefore do not impede the segmental mobility of the PEGdm. The relative proportion of the methacrylate and octyl groups on the silica surface displays a nominal effect on both rheology and conductivity following crosslinking although the pre-cure rheology is a function of the surface groups. Chemical crosslinked nanocomposite polymer electrolytes offer significant higher elastic modulus and yield stress than the physical nanocomposite counterpart with a small/negligible penalty of transport properties. The crosslinked CPEs exhibit good interfacial stability with lithium metal at open circuit, however, they perform poorly in cycling of lithium–lithium cells.
Nanoscale Young's modulus mapping of the cross-section of electrode composite films used in lithium ion batteries was carried out using bimodal atomic force microscopy. Clear difference in Young's modulus was observed between the particles of active materials and matrix of conductive additives/binders in the composites of LiCoO2-based positive and graphite-based negative electrodes. Interestingly, there were a few particles showing significantly reduced Young's modulus in the 100% state-of-charge positive electrode although such particles were not present in the pristine electrode.
Enthalpy increment measurements on melts in the system KCl–K2TaF7 were carried out by drop calorimetry at temperatures between 298 and 1053, 1093 and 1133K and selected compositions. The heat capacities of melted mixtures and enthalpies of mixing were determined using the experimental data. Calorimetric experiments showed nonideality of the melts in several properties. The molar relative enthalpy and molar heat capacity of melts exhibited small negative divergence from additivity. The molar enthalpy of mixing of melts showed exothermic deviation from ideality which increased with increasing temperature. The thermal effect at mixing was assigned predominantly to addition and substitution reactions producing heteroligand complex anions TaF6Cl2−. The nonideality was also confirmed by evaluating of activities considering Margules type model for excess Gibbs energy of mixing.
Here we report the synthesis and electrochemical performance of 40nm near-uniform lithium titanate (Li4Ti5O12) single crystals. The cubic spinel Li4Ti5O12 nanocrystals are transformed without size changes at 400°C from cubic NaCl type (Li0.4H0.6)2TiO3 nanocrystals that are prepared from hydrothermal synthesized α-Li2TiO3. The prepared Li4Ti5O12 nanocrystals show reduced charge-transfer impedance and exhibit favorable performance under high current charging/discharging due to the reduced Li+ ion diffusion path.
Based on findings in basic memory and comprehension research, we note implications for enhancing acquisition of factual information. For each implication, we identify techniques that could be implemented to assist students’ acquisition of material in fact-laden courses. We evaluate the potential effectiveness of those techniques for education practice by reviewing translational research that uses educationally relevant materials and test tasks. Specifically, extending basic memory research, we discuss implications from findings on rote repetition (rereading text), elaboration (elaborative interrogation, advanced organizers, and imagery mnemonics), and desirable difficulty (creating interference, spacing, and generation). We suggest a contextualistic framework for understanding when difficulty is and is not desirable, including considerations of transfer-appropriate processing, material-appropriate processing, and individual learner differences. Building on basic research in comprehensive, we identify study methods that are sensitive to individual differences, techniques to improve successful inferencing, and principled text revisions to enhance comprehension. The final section touches on the mnemonic benefits of retrieval and discusses recent research demonstrating the value of using repeated testing to enhance learning (i.e., to improve performance on final criterial tests). The research discussed in this chapter supports the efforts to apply basic findings in memory and cognition to enhance educational practice.
In this paper, we studied the development of a selective lithium ion sensor constituted of a carbon paste electrode modified (CPEM) with an aluminum-doped spinel-type manganese oxide (Li1.05Al0.02Mn1.98O4) for investigating the influence of a doping ion in the sensor response. Experimental parameters, such as influence of the lithium concentration in the activation of the sensor by cyclic voltammetry, pH of the carrier solution and selectivity for Li+ against other alkali and alkaline-earth ions were investigated. The sensor response to lithium ions was linear in the concentration range 5.62×10−5 to 1.62×10−3 molL−1 with a slope 100.1mV/decade over a wide pH 10 (Tris buffer) and detection limit of 2.75×10−5 molL−1, without interference of other alkali and alkaline-earth metals, demonstrating that the Al3+ doping increases the structure stability and improves the potentiometric response and sensitivity of the sensor. The super-Nernstian response of the sensor in pH 10 can be explained by mixed potential arising from two equilibria (redox and ion-exchange) in the spinel-type manganese oxide.