batterydata/paper-abstracts huggingface dataset:
We have developed a hydrogen generator that generates high purity hydrogen gas from the aqueous solution of sodium borohydride, NaBH4. This paper discussed the performance testing of the hydrogen generator using a Pt-LiCoO2-coated honeycomb monolith. The NaBH4 solution hydrolyzed to generate H2 and sodium metaborate when it contacted the monolith. The gravimetric and the volumetric H2 densities of the system were 2wt.% and 1.5kg H2/100l, respectively. The volumetric density was similar to that of the compressed H2 at 25MPa. The hydrogen generator successfully provided a maximum H2 generation rate of 120nl/min. Assuming a standard PEM (polymer electrolyte fuel cell, PEFC) fuel cell operated at 0.7V, generating 120nl/min was equivalent to12kW.
2V lead-acid cell employing RVC galvanized with Pb as the grid material has been designed and tested. Two thick (>0.5cm) plates have been used for assembling prototype flooded cell. It completed over 65 charge/discharge cycles at 50% depth of discharge without losing its nominal capacity. For higher discharge currents at 100% DOD the cyclic lifetime is limited as a result of grid corrosion which is probably due to relatively thin, non-alloyed pure lead grid coating. However, very promising capacity values for 20-h discharge rate at the level of 120Ahkg−1 PAM, 170Ahkg−1 NAM have been obtained, the high current response is still below the expectations. Average internal resistance of the new cells is 45mΩ, which is in parallel with limited high-current response. Perspective of designing serial lead acid cell employing lightweight reticulated carbon as a grid material is clearly visible. There is a need of introducing high-quality, corrosion resistant Pb-alloy for RVC coating and lowering the plates thickness for better high current performance.
Developing electrolytes that enable commercially viable lithium metal anodes for rechargeable lithium batteries remains challenging, despite recent exhaustive efforts. Electrolytes of similar composition, yet different structure, have been investigated to understand key mechanisms for improving the cycling performance of lithium metal anodes. Specifically, the electrolytes investigated include LiPF6, LiBF4, lithium bis(oxalato)borate (LiBOB), and lithium difluoro(oxalato)borate (LiDFOB) dissolved in a mixture of ethylene carbonate (EC) and ethyl methyl carbonate (EMC). There is a remarkable difference in the cycling performance of 1.2 M LiDFOB in EC:EMC (3:7) compared to 0.6 M LiBF4 + 0.6 M LiBOB in EC:EMC (3:7), despite the effectively equivalent chemical composition. The LiDFOB electrolyte has significantly better cycling performance. Furthermore, the chemical compositions of the SEI generated on the lithium metal electrode from the two electrolytes are very similar, especially after the 1st plating, suggesting that the chemical composition of the SEI may not be the primary source for the difference in cycling performance. Ex situ transmission electron microscopy (TEM) reveals that the difference in cycling performance can be traced to the presence of nanostructured LiF particles in the SEI from the LiDFOB electrolyte. It is proposed that the capping ability of the oxalate moiety from LiDFOB, in combination with simultaneous generation of LiF, leads to generation of uniform and evenly distributed nanostructured LiF particles. The presence of nanostructured LiF in the SEI results in uniform diffusion field gradients on the lithium electrode which leads to improved cycling performance. The proposed mechanism not only provides insight for improving lithium metal anodes for batteries, but also expands upon the understanding of the role of LiF in the SEI on graphite electrodes in commercial lithium ion batteries. A superior understanding of the structure and function of the SEI will facilitate the development of next-generation energy storage systems.
Abstract This chapter addresses both the challenges and benefits of fabricating gas sensors using complementary metal oxide semiconductor (CMOS) technology and the integration of associated circuitry onto a single silicon chip. The main objective described here is, specifically, the development of ultra-low power (∼mW) resistive and calorimetric gas sensors that can operate at high temperatures (up to 600 °C) on a thin (∼μm) CMOS platform. Compatibility with standard CMOS technology permits high volumes of production (>100k dies per annum) at very low unit cost (<$1). We present, in turn, the design of interface electronics for these high-temperature gas sensors, the necessity of having sensor arrays when employing nonselective gas sensing materials, and the exploitation of a new generation of gas-sensitive nanomaterials for superior CMOS devices. Finally, the future prospects of smart CMOS-based gas (or odor) sensors are considered with particular focus on emerging applications and possible new markets.
The kinetic processes during delithiation/lithiation of Li x Mn0.8Fe0.2PO4 are thoroughly investigated through operando x-ray diffraction and in situ electrochemical impedance spectroscopy combined with galvanostatic intermittent titration technique (GITT), by which new insights on the phase propagation and sluggish kinetics of LiMn0.8Fe0.2PO4 (LMFP) cathode materials are elaborated. In situ analyses on the solvothermally synthesized carbon-coated LMFP mesocrystals reveal that the phase-propagation mechanisms differ during delithiation/lithiation processes, and the sluggish kinetics of LMFP followed by the limitation of achievable (dis)charge capacities originate from the poor apparent Li+ diffusivity, which is triggered by Mn redox reaction. Based on the in-depth characterization of the reaction kinetics in LMFP mesocrystals, our work provides fundamental understanding to design high-performance Mn-based olivine cathodes.
Abstract A Contingency Plan enables you to remove risks to your system posed by outages and disruptions. The nature of unprecedented disruptions can create confusion and often predispose an otherwise competent IT staff toward less efficient practices. Confusion and inefficiency create risk. Contingency planning and testing enables you to eliminate some of that risk.
This paper reports a study on anxiety in Chinese undergraduate non-English majors at three different proficiency levels. By way of survey, observations, reflective journals and interviews, the study revealed that (1) a considerable number of students at each level felt anxious when speaking English in class, (2) the more proficient students tended to be less anxious, (3) the students felt the most anxious when they responded to the teacher or were singled out to speak English in class. They felt the least anxious during pair work, and (4) with increasing exposure to oral English, the students felt less and less anxious about using the target language in speech communication. Based on the findings, some suggestions for future research are proposed.
This paper proposes a systematic method of system identification and control of a proton exchange membrane (PEM) fuel cell. This fuel cell can be used for low-power communication devices involving complex electrochemical reactions of nonlinear and time-varying dynamic properties. From a system point of view, the dynamic model of PEM fuel cell is reduced to a configuration of two inputs, hydrogen and air flow rates, and two outputs, cell voltage and current. The corresponding transfer functions describe linearized subsystem dynamics with finite orders and time-varying parameters, which are expressed as discrete-time auto-regression moving-average with auxiliary input models for system identification by the recursive least square algorithm. In the experiments, a pseudo-random binary sequence of hydrogen or air flow rate is fed to a single fuel cell device to excite its dynamics. By measuring the corresponding output signals, each subsystem transfer function of reduced order is identified, while the unmodeled, higher-order dynamics and disturbances are described by the auxiliary input term. This provides a basis of adaptive control strategy to improve the fuel cell performance in terms of efficiency, as well as transient and steady state specifications. Simulation shows that adaptive controller is robust to the variation of fuel cell system dynamics, and it has proved promising from the experimental results.
Nepal, one of the least developed countries, is characterized by low per capita energy consumption and hugely dominated by traditional energy sources. Despite having enormous potential of hydro-electricity, only 50% of the total population has access to grid electricity. Firewood is the primary energy source for domestic purposes in rural environments. Due to geographical remoteness, a scattered consumer, higher costs of supply and maintenance, low consumption and low level of households’ income linking the rural areas to national electricity grid is difficult and implausible. In order to solve the energy problem in rural areas, Nepal’s government has initiated the production and distribution of several renewable energy technologies. Among several renewable technologies, micro-hydropower has been one of the most promising and widely adopted decentralized technologies to distribute electricity in rural areas. This article begins with a general overview of energy situation in Nepal. Present status and perspective of micro-hydro plants have also been discussed. Similarly, the dynamics of the relationship between electricity and socio-economic development has been analyzed by means of a typical rural electrification project in Tangting, Nepal by assessing the impacts of electricity on health, education, environment, and income in the village. The community has greatly benefitted from the arrival of environment friendly and affordable electricity. It has been concluded that the task of providing electricity to more remote and isolated villages is still challenging in Nepal. More systematic and comprehensive study supported by research and development is required to extend micro-hydro based electricity in more remote and poor communities of Nepal.
Herein, we propose a facile incomplete phase separation strategy unlike the tedious synthesis approaches of the past to fabricate P/N co-doped porous and interconnected carbon (PNPC) particles with a specific surface area (SA) of 1920 m2 g−1. The heteroatom doped porous carbons were demonstrated to possess improved conductive property and excellent stability for supercapacitor application. The PNPC bunch delivered a high specific capacitance of 318 F g−1 at 1 A g−1 and a remarkable cycling stability, i.e., 96.2% initial capacitance after 10,000 cycles in 6 M KOH electrolyte solution. In addition, an asymmetric supercapacitor (ASC) employing LaNi0.5Co0.5O3/0.333Co3O4 hollow spheres with a mesoporous shell as a positive electrode and PNPC bunch as a negative electrode showed a maximum specific capacitance of 109.6 F g−1 at 1 A g−1 in a potential window of 0–1.7 V. More importantly, the reformative ASC can be discharged up to 0.5 s at a charge current density of 1 A g−1 to deliver an ultrahigh power density of 89.7 kW kg−1, much higher than those of the reported ASCs. This exciting result paves a way for practical application in high power devices.
Substantial interests have been paid to Na-based electrode materials due to the abundance and low cost of sodium resources on earth. In this study, we improved the electrochemical performance of NaVPO4F cathode by coating graphene sheets. The structure, composition and morphology of NaVPO4F/graphene composite were investigated by XRD, FT-IR, FE-SEM and TEM. FE-SEM and TEM analysis indicate that the graphene sheets were successfully coated on the surface of NaVPO4F. The NaVPO4F/graphene composite could be operated at a high working potential (3.95V for average voltage), and displayed the highest capacity of 120.9mAhg−1. After 50 charge/discharge cycles at 0.05C, the capacity retention of the cathode could reach up to 97.7%. Although the discharge capacity of NaVPO4F/graphene decreased to 70.1mAhg−1 under a high rate of 0.5C, it returned back to 113.2mAhg−1 once the rate was reduced to 0.05C. EIS measurement further reveals that the NaVPO4F/graphene electrode exhibited a faster sodium-ion diffusivity and less resistance compared with the pure NaVPO4F. Our results demonstrate that NaVPO4F/graphene is a promising cathode material for sodium ion batteries.
Pure and Sn-modified LiFePO4 crystalline powders are successfully synthesized by sol-gel method. The addition of Sn to the precursor changes the morphology of the material causing partial formation of nanorods and leads to increase of average crystallite size from 33nm up to ca. 40nm. The X-ray photoelectron spectroscopy, transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy indicate that Sn outdiffuses to the LiFePO4 crystal surface during calcination process and creates a few nanometer-thick SnO2 surface layer. The TEM analysis combined with Raman spectroscopy indicates also that LiFePO4 particles are embedded in amorphous carbon. Electrochemical testing shows an improved capacity, as well as better stability and cycling reversibility of Sn-modified materials compared to pure LiFePO4. Reduced material degradation during charging/discharging cycling and excellent lithium intercalation reversibility in Sn-modified LiFePO4 is attributed to a positive surface modification effect of the SnO2 layer.
Species invasions are often associated with large-scale human alteration of ecosystems. One classic example is the increasing dominance of non-native taxa below and above dams on large rivers. These dams substantially alter the physical template of river ecosystems, and exotic taxa often proliferate with potentially large impacts on coexisting taxa and ecosystem processes. Here we document the invasion of New Zealand mud snails (Potamopyrgus antipodarum) in the Colorado River directly below Lake Powell in Glen Canyon, Arizona, USA. We also quantified the magnitude and variability in growth and secondary production of P. antipodarum during 2006–2007 to gain a functional measure of their role in the ecosystem. Snails were first detected in Glen Canyon in 1995, and have since become a dominant component of the invertebrate fauna. Throughout the invasion of P. antipodarum, biomass of other dominant taxa was variable and did not appear to be positively or negatively influenced by the presence of P. antipodarum. Specific growth rates of P. antipodarum were moderate (0.001–0.030 day−1) and strongly related to body size. Mean annual habitat-weighted biomass and production were relatively high (biomass: 4.4 g/m2; secondary production: 13.3 g m−2 year−1) and similar among habitats. Mean monthly biomass and daily secondary production were much more variable, with highest values occurring in autumn. We show that invasion of a productive aquatic consumer to a highly disturbed river ecosystem had little detectable influence on the biomass of other invertebrate taxa. However, additional research will be necessary to fully understand and predict effects of P. antipodarum on coexisting taxa.
The safety of lithium ion batteries is correlated closely to the mechanical property and thermal stability of separators. The polymer/ceramic particle composite separators are widely investigated for quasi-solid gel separators of lithium ion batteries, but the nonuniform dispersion of ceramic particles limits their performance. In this study, ball-milled Al-doped Li6.75La3Zr1.75Ta0.25O12 suspension is incorporated into poly (vinylidene fluoride-co-hexafluoropropylene) gel to prepare a highly uniform quasi-solid composite separator. The results show that adding only 4.29 wt% Li6.75La3Zr1.75Ta0.25O12 into PVDF-HFP increases ductility by three times and the mechanical strength by 38% as compared with pure PVDF-HFP separator. Batteries with the composite separator show significantly improved cyclic stability and rate performance at both room temperature and temperatures up to 80 °C. In particular, the composite separator promotes homogenous Li+ flux through the separator and suppresses Li dendrite growth in Li-metal based batteries.
To examine the prospective association between serum Mg level and the incidence of cognitive impairment.
Sulfur-doped disordered carbon is facilely synthesized and investigated as an anode for sodium ion batteries. Benefiting from the high sulfur doping (∼26.9 wt%), it demonstrates a high reversible capacity of 516 mA h g−1, excellent rate capability as well as superior cycling stability (271 mA h g−1 at 1 A g−1 after 1000 cycles).
Objective To investigate the psychometric properties of the Brief Fatigue Inventory (BFI) in community-dwelling older adults. Design Cross-sectional validation study. Setting Community based. Participants Subjects (N=302) were nondemented older adults (mean age, 76.44y; 54% women). Interventions Not applicable. Main Outcome Measures BFI total, severity, and interference summation scores. Results A principal component analysis (PCA) yielded 2 factors, fatigue severity and interference, explaining 65.94% of the variance. Both factors had good reliability, with Cronbach alpha values of .867 for fatigue interference and .818 for fatigue severity. Higher fatigue scores were associated with older age and worse physical and cognitive functions. Conclusions Fatigue is a common and debilitating symptom in the aging population. The current study provides novel findings in validating and establishing a bidimensional factor structure for the BFI in older adults. Severity and interference were differentially related to important health outcomes; therefore, using these subscales in addition to the total BFI score is recommended with older adults. Because of its relatively short administration time and established psychometric properties, the BFI can be successfully incorporated into longitudinal studies and clinical trials.
The core-shell structural N-doped carbon encapsulating Si@TiO2 composite (Si@TiO2/NC) are prepared by facile sol-gel, polymerization of dopamine hydrochloride and the following heat treatment processes, which are confirmed by the scanning electron microscopy, X-ray diffractometer, transmission electron microscopy, X-ray photoelectron spectroscopy and thermogravimetric analyses. The as-prepared Si@TiO2/NC composite present favorable spherical shape with about 150 nm in diameter and uniform element distribution, and demonstrate the enhanced electrochemical properties compared to the pure silicon, Si@TiO2 and Si/NC materials when the composite materials are used as anodes for lithium-ion batteries, in which the Si@TiO2/NC composite anodes display the favorable initial coulombic efficiency of 75.9%, remarkable charge specific capacity of 1070.9 mAh g−1 with the coulombic efficiency approaching 100% after 100 cycles under the test current of 200 mA g−1, extraordinary rate and cycle capability with the charge specific capacity of 696.2 mAh g−1 under the test current of 3000 mA g−1 and increased lithium ion diffusion coefficient from 8.179 E-12 cm2 s−1 to 8.995 E-12 cm2 s−1 after 100 cycles. Those excellent electrochemical properties can be attributed to the synergistic effect of the robust TiO2 skeleton and the elastic conductive N-doped carbon network, indicating the as-prepared Si@TiO2/NC composite could be a promising anode for lithium-ion batteries.
Impedance spectra (50kHz–1Hz) were acquired and used to obtain the differential capacitance at the interfaces between 1-butyl-3-methylimidazolium hexafluorophosphate, [BMIM][PF6] ionic liquid and three different electrode materials (Hg, Pt, and glassy carbon (GC)) as a function of the applied potential. The electrocapillary curve for the Hg/[BMIM][PF6] interface was obtained from drop time measurements, from which the potential of zero charge was calculated to be −0.39V (Ag wire). The potential of zero charge is 0.30V less negative than the potential of differential capacitance minimum. This disagreement suggests that the differential capacitance minimum is not related to a classical diffuse layer minimum. Additional support to this conclusion was obtained from positive temperature coefficient for the differential capacitance in contrast to the negative temperature predicted by the classic Gouy-Chapman model. The results do not support the recent model predictions of bell shaped capacitance curves for room temperature ionic liquids, RTILs.
Hadn’t this question already been answered? We all know about computation-universal Turing Machines. And we know that any such machine can simulate a space–time dynamics not unlike von Neumann’s cellular automaton (CA), which is computation- and construction-universal and among other things can play host to self-replicating machines. And that self-replication sprinkled with a bit of randomness should inexorably lead to descent with variation, competition, and thence to evolution and all that. “So what?” Enrico Fermi would have asked, “Where is your emergent life?” (and note that our understanding of both natural and artificial life has much advanced in the 50 years since). It turns out that life is by its very nature a marginal, fragile, and ephemeral kind of phenomenon. For a substrate or a “culture medium” to be able to support the emergence from scratch of a lifelike lineage, computation- and construction-universality are necessary—but by no means sufficient! Paraphrasing Fermi, what automata that you know—including von Neumann’s CA and Conway’s very game of Life—have managed so far to “capture for us on film” the origin of some kind of life? What questions, then, should we ask of a prospective medium—be it a Turing machine, a CA, or some other kind of automaton—that will best probe its capabilities to originate (as well as sustain) some form of life, and which will provide us with a sense of direction to help us more quickly converge in this quest.
Ti x Sn1−x O3 solid solutions were prepared by a hydrothermal process. The morphologies and structures of Ti x Sn1−x O3 solid solutions were investigated by scanning electron microscope, transmission electron microscope and X-ray diffraction measurements. The electrochemical properties of Ti x Sn1−x O3 solid solution electrodes with different Sn/Ti ratios were examined by a variety of electrochemical testing methods. It was found that, the Ti x Sn1−x O3 solid solution showed not only higher specific capacity of 506mAhg−1 after 30 cycles but also better cycle performance, superior than the pure SnO2 electrode, which can be ascribed to the stable cyclability of TiO2 and the high reversible capacity of nanosized SnO2. The Ti x Sn1−x O3 solid solutions would be a potential candidate as anode material for a new generation lithium ion batteries.
Practical agent languages and their corresponding architectures have often relied on a static plan library with more or less direct trigger-response activation mechanisms as a source for agent behaviours for the sake of runtime efficiency. Although efficient, such a language design choice severely limits an agent’s ability to reason about its goals and adapt to unforeseen circumstances after being deployed. This effectively delegates the task of planning to the designers themselves, who must design plan libraries able to cope with every foreseeable situation an agent might find itself in by designing plans to deal with any contingency. In this paper we develop a formal conversion process from traditional BDI agent languages into declarative planning. Using this conversion process, we show how to integrate domain independent planning algorithms into the BDI interpreter, allowing a designer to program an agent not only through the trigger-response mechanism used in traditional languages, but also in terms of declarative goals. Our contribution here is twofold: firstly we increase an agent’s ability to cope with unforeseen situations and secondly we unburden an agent designer from having to define multiple plan combinations that could be easily generated by a planner.