batterydata/paper-abstracts huggingface dataset:
LiFePO4 is one of the most promising cathode materials for Li-ion batteries. However, its low electronic conductivity and slow Li-ion diffusion rate lead to poor electrochemical performance, especially poor rate performance. The hybrid of LiFePO4/Nitrogen and Sulfur co-doped graphene is successfully synthesized via a self-assembly method. Given its Nitrogen and Sulfur co-doped graphene matrix, the hybrid exerts a significantly impact on the electron conductivity of LiFePO4, resulting in excellent electrochemical properties and power density. The LiFePO4 composite has reversible capacity of 106.1 mAhg −1 at 10 C and 94.6 mAhg−1at 15 C. Moreover, with less than 5% loss of discharge capacity after 500 cycles at 10 C, the Nitrogen and Sulfur co-doped graphene can effectively improve the electrochemical performance of LiFePO4.
Reductive precipitation of Sn(II) chloride by NaBH4 is assisted by electrospraying in order to achieve a fine dispersion of the liquid precursor solution into the reductive bath. The formation of a highly charged aerosol of precursor droplets enables the size reduction of the constitutive units for the synthesized materials. Nanostructured Sn-based powders resulting from this process are tested as negative electrodes in Li cells. The presence of nanostructures has a significant influence on the cycling behaviour of the materials, which retained a capacity of about 300mAhg−1 after 100 cycles measured between 0.05 and 1.20V.
Following a stroke, patients can have problems speaking and understanding language (aphasia). During the past decade, several therapies for poststroke aphasia have been developed on the basis of knowledge gained from advances in neuroscience research. In this article, Berthier and Pulvermüller provide an overview of these advances in poststroke neurorehabilitation and highlight the physiological processes that are considered to underlie their beneficial effects.
Despite significant antiemetic advances, almost 50 % of treated cancer patients still experience nausea and vomiting (N&V). The goal of antiemetic therapy—complete prevention of treatment-induced nausea and/or vomiting (TIN+/−V)—remains elusive for several reasons. Potentially, N&V may be part of a symptom cluster where co-occurring symptoms negatively affect antiemetic management. Consequently, we examined TIN+/−V incidence and the impact of nausea, vomiting and symptom cluster(s) containing them, respectively, on patients’ quality of life (QoL) and psychological adjustment across treatment.
This paper proposes an algorithm for the inclusion of analogy into Explanation-Based Learning (EBL). Analogy can be used when an impasse is reached to extend the deductive closure of EBL’s domain theory. This enables the generation of control laws, via EBL, for hardware which is not catered for in the domain theory. This advantage addresses a problem which represents a dearth in the current literature. Integrated Modular Avionics (IMA) literature has thus far been concerned with the architectural considerations. This paper seeks to address the impact of hardware changes on the controllers within an IMA architecture. An algorithm is proposed and applied to control an aviation platform with an incomplete domain theory. Control rules are generated when no deductive explanations are possible, which still reflect the intent of the domain theory.
Purpose Newer continuous-flow left ventricular assist devices (LVAD) have the advantage of smaller size and increased durability. Questions remain regarding the safety and effects of long-term nonpulsatile flow, despite some animal and human studies showing that end-organ function is well maintained with pulsatile or axial-flow devices. This study investigated whether centrifugal devices have similar effects on end-organ function. Methods All patients who underwent LVAD implantation as bridge-to-transplant (BTT) therapy from January 2004 through May 2007 were reviewed. Excluded were patients on biventricular support, destination therapy, temporary support, and patients who died within 30 days after LVAD implantation. The centrifugal device was the VentrAssist (Ventracor Ltd, Sydney, Australia); axial, the HeartMate II; and pulsatile, the HeartMate XVE (Thoratec Corp, Pleasanton, CA). Results During the study, 10 VentrAssist, 30 HeartMate II, and 18 HeartMate XVE devices were implanted. Among the 3 groups, age, gender, weight, duration of LVAD support, and cause of heart failure were comparable. No significant differences were found between groups with respect to baseline renal function, hepatic function, or hematologic function. At 1 and 3 months of follow-up, renal and hepatic function either improved or remained within normal limits in all groups. Conclusions Centrifugal, axial, and pulsatile LVADs all provide adequate circulatory support to maintain appropriate end-organ function in patients with end-stage heart failure. The advantages of the newer continuous-flow devices can be safely applied to an increasing number of patients. Long-term studies (>1 year) are needed to assess effects on end-organ function with continuous-flow devices, which may have important implications for use as destination therapy.
The ever-increasing boom in smart, miniaturized electronics has led to an urgent need for on-chip energy storage systems that exhibit high performance, safety, flexibility and robust integration. However, tremendous challenges exist. Here, we demonstrate the first prototype of all-solid-state planar lithium ion micro-capacitors (LIMCs) based on interdigital patterns of lithium titanate nanospheres as the anode and activated graphene as the cathode. The interdigital LIMCs were fabricated via layer-by-layer mask-assisted deposition of graphene and electrode materials, without the need for metal current collectors, additives or polymer binders. The as-assembled LIMCs delivered a record volumetric energy density of 53.5 mW h cm−3. Furthermore, they exhibited outstanding mechanical flexibility without performance degradation under repeated bending, superior electrochemical metrics and safety at a high temperature of 80 °C due to the highly stable ionogel electrolyte and the absence of a separator. Additionally, our microdevices presented remarkable modular integration of the constructed bipolar cells for boosting high voltage and capacitance. Therefore, these LIMCs hold great potential for application in future flexible and wearable electronics.
The claim that the 2008 presidential election was a transformative one is fast becoming part of the conventional wisdom of American politics. Despite the election’s undoubted significance, this paper argues that factors affecting voting decisions were strikingly similar to those operating in many previous presidential elections. Using data from the CCAP six-wave national election survey, we demonstrate that a valence politics model provides a powerful, parsimonious explanation of the ballot decisions Americans made in 2008. As is typical in presidential elections, candidate images had major effects on electoral choice. Controlling for several other relevant factors, racial attitudes were strongly associated with how voters reacted to the candidates. Other models of electoral choice, such as a Downsian issue-proximity model, are also relevant, but their explanatory power is considerably less than that provided by the valence politics model.
The chitinase gene was molecularly characterized in five Bacillus thuringiensis Mexican isolates, MR10, MR11, MR21, MR33, and RN52. The proteins derived from these genes were tested for their chitinase activity using fluorogenic chitin derivatives. In order to verify if chitinase genes were functional, they were cloned, and enzymatic activity of recombinant chitinases was also tested. Results indicated that enzymes exhibited endochitinase activity. The highest hydrolytic activity shown against the chitin tetrameric derivative occurred at pH value of 6.5, and the optimum activity temperature was around 60 °C. The recombinant endochitinases showed a molecular mass of ∼77 kDa with isoelectric points from 6.5 to 7.0. Analysis of the nucleotide sequences showed highly conserved sequences among all isolates (97–99 %). Gene sequence analysis revealed a putative promoter (−35 TTGAGA and −10 TTAATA) and a Shine–Dalgarno sequence (5´-AGGAGA-3´) upstream from the open reading frame. The deduced amino acid sequence revealed that the proteins are modular enzymes composed by a family 18 glycosyl hydrolase domain located between amino acids 134 and 549, a fibronectin-binding domain (580 through 656), and a chitin-binding domain (664 through 771). The deduced amino acid sequences of our isolates showed a similarity close to 100 % respect to the sequences reported in the GenBank database.
Li3V2(PO4)3/C composite cathode material was synthesized via carbothermal reduction process in a pilot scale production test using battery grade raw materials with the aim of studying the feasibility for their practical applications. XRD, FT-IR, XPS, CV, EIS and battery charge–discharge tests were used to characterize the as-prepared material. The XRD and FT-IR data suggested that the as-prepared Li3V2(PO4)3/C material exhibits an orderly monoclinic structure based on the connectivity of PO4 tetrahedra and VO6 octahedra. Half cell tests indicated that an excellent high-rate cyclic performance was achieved on the Li3V2(PO4)3/C cathodes in the voltage range of 3.0–4.3V, retaining a capacity of 95% (96mAh/g) after 100 cycles at 20C discharge rate. The low-temperature performance of the cathode was further evaluated, showing 0.5C discharge capacity of 122 and 119mAh/g at −25 and −40°C, respectively. The discharge capacity of graphite//Li3V2(PO4)3 batteries with a designed battery capacity of 14Ah is as high as 109mAh/g with a capacity retention of 92% after 224 cycles at 2C discharge rates. The promising high-rate and low-temperature performance observed in this work suggests that Li3V2(PO4)3/C is a very strong candidate to be a cathode in a next-generation Li-ion battery for electric vehicle applications.
Rentschler AJ, Cooper RA, Fitzgerald SG, Boninger ML, Guo S, Ammer WA, Vitek M, Algood D. Evaluation of selected electric-powered wheelchairs using the ANSI/RESNA standards. Arch Phys Med Rehabil 2004;85:611–9. Objectives To compare the performance characteristics of different electric-powered wheelchairs (EPWs) and to evaluate the effectiveness of the American National Standards Institute/Rehabilitation Engineering and Assistive Technology Society of North America (ANSI/RESNA) wheelchair standards. Design Five types of EPWs were selected. Three wheelchairs of each type were tested according to the ANSI/RESNA wheelchair standards. Setting Rehabilitation engineering center. Specimens Fifteen wheelchairs. Interventions Not applicable. Main outcome measures Static tipping angle; dynamic tipping score; braking distance; energy consumption; static, impact, and fatigue strength; and climatic conditioning. Results There were significant differences (P<.05) among the 5 types of EPWs for static stability when facing both uphill and downhill in the most-stable and least-stable configurations. There were significant differences (P<.05) among the EPWs on most of the dynamic stability tests. There were also significant differences (P<.05) among EPWs for all the effectiveness of brakes conditions, as well as between 2 wheelchairs for the energy consumption testing. There were several failures among the wheelchairs during the static, impact, and fatigue strength testing and during the climatic testing. Conclusions The results show that EPWs can vary greatly with respect to static and dynamic stability, braking distance, range, strength testing, and climatic conditioning. All these factors have a substantial effect on safety and performance.
A simple sodium dodecyl benzene sulfonate (SDBS) mediated hydrothermal method has been described in this paper to prepare morphology-controlled LiFePO4, cathode material such as nanoparticles, nanorods and nanoplates with controllable b-axis thickness. When used in lithium-ion batteries, the LiFePO4/C nanoparticles (200 nm in size) and nanorods (90 nm in diameter along b-axis and 200 nm–1 μm in length) display initial discharge capacities of 145.3 and 149.0 mAh g−1 at 0.1 C rate, 33.9 and 61.3 mAh g−1 at 10 C rate, respectively. The LiFePO4/C nanoplates (20 nm thickness along b-axis and 50 nm width) deliver a discharge capacity of 162.9 mAh g−1 at 0.1 C rate and 107.9 mAh g−1 at 10 C rate. The Li-ion diffusion coefﬁcients of the LiFePO4/C nanoparticles, nanorods and nanoplates are calculated to be 1.66 × 10−12, 2.99 × 10−12 and 1.64 × 10−11 cm2 s−1, respectively. In general, the discharge capacity and rate performance have been found to increase with the decreasing thickness of the b-axis. The experimental results demonstrate that decreasing the crystallite size in the b-axis and increasing the surface area of (010) plane can shorten Li-ion diffusion path and increase the electrode reaction, which significantly improve electrochemical performance of the LiFePO4/C nanocomposites.
The presented work designs a facile strategy to prepare Mo2C nanoplates assembled by ultrafine nanoparticles with amine-metal oxide as the precursor. When served as anode material for sodium ion batteries, the resultant material exhibits excellent sodium storage properties in terms of long term cycling stability and high rate capability. In details, the Mo2C electrode delivers a reversible capacity of 90.8mAhg−1 at 200mAg−1 after 400 cycles and a high rate capability of 93.7 and 64.1mAhg−1 at 0.5 and 1Ag−1, respectively, which could be attributed to the highly exposed active sites of Mo2C nanoplates and intimate connection between Mo2C nanoplates. Furthermore, the diffusion coefficients of the sodium ions based on the EIS measurement have been calculated in the range of 10−12–10−9 cm2 s−1, revealing an excellent diffusion mobility for Na atoms in the Mo2C nanoplates. This study demonstrates that the Mo2C is a promising anode material for sodium ion batteries.
The safety issue and poor stability induced by dendrite growth and volume change present major barriers to the practical application of lithium-metal anode for next-generation high-energy-density batteries. Herein, we propose vertically aligned ZnO nanosheets derived from zinc-based MOF grown on Ni foam (LZNF) as a lithiophilic porous scaffold to mitigate these problems. The interspace between the cross-linked ZnO nanosheets as the lithiophilic reservoir enables homogenous plating/stripping of Li at a high deposition capacity of 15 mAh cm-2, which is difficult to realize on Ni foam substrate decorated with normal ZnO particles. The integration of vertically aligned ZnO nanosheets and 3D conductive Ni foam can not only induce dendrite-free lithium deposition with reduced current density but also alleviate the volume fluctuations of lithium. Consequently, a high Coulombic efficiency in LZNF/Li half-cell (98.5% for 150 cycles at 1 mA cm-2) and enhanced cycling stability of a symmetric LZNF@Li/LZNF@Li cell (5 mA cm-2 for 250 cycles) with a small voltage hysteresis (45 mV) can be achieved. Our investigation shows that LZNF can serve as a promising multi-functional 3D host for dendrite-free Li metal anodes.
This article describes a battery charger, which is powered by thermoelectric (TE) power modules. This system uses TE devices that directly convert heat energy to electricity to charge a battery. The characteristics of the TE module were tested at different temperatures. A SEPIC dc–dc converter was applied and controlled by a microcontroller with the maximum power point tracking (MPPT) feature. The proposed system has a maximum charging power of 7.99W: that is better than direct charging by approximately 15%. The objectives are to study the principle of TE power generation and to design and develop a TE battery charger that uses waste heat or another heat source as the direct input power.
Based on the porous electrode and concentrated solution theory, a thermal model is developed for lithium ion battery pack. The accuracy of predicted battery temperatures is validated by charge–discharge cycling experiments under natural and forced convection conditions. The heat generation and dissipation rates of battery under different conditions are simulated by the proposed model and the results indicate that: (1) the SOC change has a significant effect on the reversible heat generation rate but has almost no influence on the irreversible heat generation rate; (2) the generation rates of reversible and irreversible heat during charge are almost equal to that during discharge with the same SOC and current rate, but the effect of reversible heat on battery temperature is opposite; (3) for enhancing heat dissipation with a given input power of cooling fan, there always exists an optimum value for the resistance coefficient of battery pack, and the optimal coefficient is increased when the input power of fan increases. In addition, the comparisons between the predicted and measured battery temperature indicate that, the reversible heat has significant influence on battery temperature during continuous charge and discharge, especially under low current rate, but the influence can't be observed during charge–discharge cycles.
Nano-sized silver particle (<20nm) was highly dispersed on the surface of Li4Ti5O12 particles by an electroless deposition method. The Ag additive played a positive role in improving the electrical contact between Li4Ti5O12 particles and the current collector and therefore improved the high rate capacity of Li4Ti5O12, but it did not take part in the electrochemical reactions with Li+ in Li4Ti5O12/Ag composite during the cycling. The experimental results showed that the smaller the silver particles and the more homogeneous dispersion of silver particles in the Li4Ti5O12 matrix, the better the cycling performance we obtained.
Transient electronics (or biodegradable electronics) is an emerging technology whose key characteristic is an ability to dissolve, resorb, or physically disappear in physiological environments in a controlled manner. Potential applications include eco-friendly sensors, temporary biomedical implants, and data-secure hardware. Biodegradable electronics built with water-soluble, biocompatible active and passive materials can provide multifunctional operations for diagnostic and therapeutic purposes, such as monitoring intracranial pressure, identifying neural networks, assisting wound healing process, etc. This review summarizes the up-to-date materials strategies, manufacturing schemes, and device layouts for biodegradable electronics, and the outlook is discussed at the end. It is expected that the translation of these materials and technologies into clinical settings could potentially provide vital tools that are beneficial for human healthcare.
Silicon working as anode for Li-ion batteries has attracted much attention due to its high capacity (∼4200mAhg−1). However, due to the large volume expansion during lithiation, the capacity of silicon fades very fast. In this systematic study, we focus on the issue to fight the capacity fading. Results show that Si with sodium carboxymethyl cellulose (Na-CMC) as a polymer binder exhibits a better cyclability than that with poly(vinylidene fluoride) (PVDF). Yet differing from the system used in PVDF, the addition of vinylene carbonate (VC) does not improve or even worsens the performance of the system using Na-CMC. In addition, the small particle size of Si, a large amount of carbon black (CB), the good choice of electrolyte/conducting salt and charge–discharge window also play important roles to enhance the cyclability of Si. It is found that electrode consisting of 40wt.% nano-Si, 40wt.% carbon black and 20wt.% Na-CMC (pH 3.5) displays the best cyclability, and in the voltage range from 0 to 0.8V, after 200 cycles, its capacity can still keep 738mAhg−1 (C/2, in 1M LiPF6 ethylene carbonate/diethyl carbonate electrolyte, with VC-free), almost twice as that of graphite.
The transplantation of human umbilical cord blood (UCB) CD34+ cells has been successfully used to treat hematological disorders but one major limitation has been the low cell numbers available. Mesenchymal stem cells (MSCs) lying within the bone marrow in vivo behave like a scaffold on which CD34+ cells interact and proliferate. We therefore evaluated the use of allogeneic MSCs from the human UC Wharton’s jelly (hWJSCs) as stromal support for the ex vivo expansion of CD34+ cells.
Summary This paper analyzes the absorptive capacities of automotive component suppliers in South Africa. It shows that some firms design and manufacture innovative products, while others upgrade their technological capability or merely strive to attain execution competence. It suggests that the reason for the differential performance lies in the strategic use of advanced technical skills and the kind of learning about frontier technology engendered by R&D. It further discusses the ways in which foreign-owned technology is internalized more or less easily depending on whether or not it is controlled by multinational firms or by passive investors.
Three-dimesional hierarchical electrodes exhibiting multi-dimensional geometries provide exceptional advantages for advanced energy storage performance. In this work, we report the fabrication and characterization of biotemplated hierarchical-Ni/NiO electrodes enabled by thermal oxidation of electroless Ni-coated Tobacco mosaic viruses (TMVs) self-assembled on Au-coated Si micropillar arrays. Uniform NiO formation on the metallized TMV nanoscaffolds is characterized by XPS and STEM-EELS analysis and the electrochemical performance was characterized in 2M KOH solution. The hierarchical-Ni/NiO show a 3.3 and 32.6 times increase in areal capacity (81.4μAhcm−2) compared to solely nanostructured (24.3μAhcm−2) and planar electrodes (2.5μAhcm−2), respectively. The NiO electrodes show interesting capacity increase phenomenon during the initial activation cycles. Based on our experimental analysis, it is attributed to both an increase in active surface area/mesoporosity and NiO content during the initial charge/discharge cycles, and the increase has dependence on electrode geometry. The hierarhical-Ni/NiO electrode exhibit excellent cycle stability up to 1500 charge/discharge cycles at 2mAcm−2 with no capacity fading. Based on the results, the hierarchical-Ni/NiO is a promising candidate for advanced electrochemical energy storage devices.
We prepared nano-sized tin (IV) oxide (SnO2) via molten-salt technique: heating a mixture of tin tetrachloride, lithium nitrate and lithium chloride at 280°C in air. The powders are characterized by X-ray diffraction and transmission scanning microscopy techniques. The XRD studies showed a structure similar to tetragonal structure. The cyclic voltammetry studies showed characteristic cathodic peak potentials of reduction of Sn4+ to Sn metal in the first cathodic scan, and alloying–de–alloying reaction of Sn at ∼0.25 and ∼0.5V vs. Li for successive cathodic and anodic scans cycled in the voltage range, 0.005–1.0V. Galvanostatic cycling studies show that reversible capacities (MSM SnO2 prepared at 280°C) of 640, 720, 890mAhg−1 in the voltage range, 0.005–1.0V, 0.005–1.3V and 0.005–1.5V, respectively at a current rate of 100mAg−1. We also discussed the effect of particle size and its electrochemical properties in the voltage range, 0.005–1.0V.