batterydata/paper-abstracts huggingface dataset:
Smartphones are considered as one of the most essential and highly personal devices of individuals in our current world. Due to the popularity of context-aware technology and recent developments in smartphones, these devices can collect and process raw contextual data about users’ surrounding environment and their corresponding behavioral activities with their phones. Thus, smartphone data analytics and building data-driven context-aware systems have gained wide attention from both academia and industry in recent days. In order to build intelligent context-aware applications on smartphones, effectively learning a set of context-aware rules from smartphone data is the key. This requires advanced data analytical techniques with high precision and intelligent decision making strategies based on contexts. In comparison to traditional approaches, machine learning based techniques provide more effective and efficient results for smartphone data analytics and corresponding context-aware rule learning. Thus, this article first makes a survey on previous work in the area of contextual smartphone data analytics and then presents a discussion of challenges and future directions for effectively learning context-aware rules from smartphone data, in order to build rule-based automated and intelligent systems.
A sulfur-multi walled carbon nanotubes (MWCNTs) composite is prepared by the direct precipitation method as a cathode material for lithium sulfur batteries. The microstructure and morphology of the sulfur-MWCNTs composite are characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectrometer (EDS) mapping and thermogravimetric analysis (TGA). From these results, it is found that the synthesized sulfur has an orthorhombic phase and the MWCNTs are chemically well-dispersed over the whole surface of the synthesized sulfur. Electrochemical charge–discharge tests demonstrated that the sulfur-MWCNTs composite exhibits better capacity retention (63%) than that (16%) of the precipitated sulfur, which is also prepared by the direct precipitation method without MWCNTs. The enhanced cycle performance of the sulfur-MWCNTs is mainly attributed to the formation of highly conductive electron path due to the uniformly dispersed MWCNTs. Furthermore, in order to investigate the electrochemical reaction mechanism for the Li–S cell during the discharge process, the ac-impedance spectra as a function of the state of discharge are measured and analyzed.
In the current research, density functional theory calculations were carried out to investigate the potential application of bare and functionalized olympicene molecules (C19H12) as anode materials for Li-ion batteries. The interactions of Li and Li+ were studied with these molecules and the cell voltages were calculated. The results reveal that the cell voltage of this molecule is greater than some well-known carbon based materials such as C32, C60, C70 fullerenes and carbon nanotubes. The functionalization of C19H12 with the electron-donating groups such as OCH3, NH2, OH enhances the cell voltage. The OCH3 substituted olympicene exhibits the maximum cell voltage of 1.60 V, which is even greater than that of a (10,10) carbon nanotube.
Lithium iron orthosilicate (Li2FeSiO4) is an important alternative cathode for next generation Li-ion batteries due to its high theoretical capacity (330 mA h/g). However, its development has faced great challenges arising from significant structural complexity, including the disordered arrangement/orientation of Fe/Si tetrahedra, polytypes and its poorly understood Li storage and transport properties. In this context, ab-initio calculations are employed to investigate the phase stability and Li diffusion profiles of both monoclinic (P21) and orthorhombic (Pmn21) Li2FeSiO4 orthosilicates. The calculations demonstrate that formation of LiFe antisites can induce a metastability competition between both phases, with neither dominating across nearly the entire discharging profile from Li2FeSiO4 through to LiFeSiO4. Furthermore, structural instability is shown to be a serious concern at discharge concentrations below LiFeSiO4 (1 Li extraction) due to the shared occupation of Li donated electrons with oxygen 2p orbitals – rather than the hypothesized transition to a tetravalent Fe4+ state. This finding is further supported by diffusion calculations that have determined a high activation energy barrier towards fast charging and rapid phase transitions. In summary, these theoretical results provide critical and timely insight into the structural dynamics of lithium iron orthosilicate, in pursuit of high energy density cathodes.
Several state of charge estimation algorithms have been developed and validated in the past. However, due to varying validation methods, the results cannot be compared. This paper presents an approach for a generalised validation and benchmark method for state of charge estimation algorithms. The independence of standardised driving cycles is obtained by developing a synthetic load cycle. To do so, a frequency analysis is performed for 149 different driving cycles and the five major time constants are identified at 55.8s, 9s, 5.1s, 3.8s and 1s. Using the synthetic load profile, three validation profiles are created. In addition to low- and high-dynamic behaviour, long-term stability is considered at five different temperatures (−10°C, 0°C, 10°C, 25°C and 40°C). During the long-term test, the temperature varies between −10°C and 40°C. To ensure comparability, a quantitative rating technique is introduced for estimation accuracy, transient behaviour, drift, failure stability, temperature stability and residual charge estimation to evaluate the performance of different state estimation algorithms. Furthermore, the benchmark can be used to optimise the state estimator, such as a linear and an extended Kalman filter examined within this study.
We initially prepared the sulfanilic acid functionalized poly(1,4-phenylene ether ether sulfone) (SPEES-SA) membrane, and it was further modified by incorporating the different mass% of sulfonic acid functionalized zeolites to develop the composite membranes. The functionalization of zeolites was confirmed by wide-angle X-ray diffraction and X-ray photoelectron spectroscopy. The resulting SPEES-SA and its composite membranes were subjected to various techniques to investigate their physico-chemical properties. The morphology of the membranes was studied using both atomic force microscopy and scanning electron microscopy. The performance of the membranes was studied in terms of swelling behavior, water uptake, ion exchange capacity and proton conductivity with respect to mass% of functionalized zeolites. The oxidative stability was performed in Fenton's solution at 80 °C and ascertained that more than 95% of the membrane residue remained with a minimum loss of ion exchange capacity (IEC). The proton conductivity data revealed that the membranes incorporated with 8 mass% of functionalized zeolites exhibited the highest IEC values. The proton conductivity of the composite membranes incorporated with functionalized Na-ZSM-5 zeolite, Na-Beta zeolite and Na-Mordenite zeolite was found to be 0.102, 0.112 and 0.124 S cm−1, respectively. The fuel cell performance study also revealed that composite membranes incorporated with 8 mass% of functionalized Na-ZSM-5 zeolite, Na-Beta zeolite and Na-Mordenite zeolite demonstrated excellent power density of 0.37 W cm−2 at 0.97 A cm−2, 0.42 W cm−2 at 1.05 A cm−2 and 0.45 W cm−2 at 1.1 A cm−2, respectively. These data are much superior to the commercially available Nafion® 117 membrane. Thus, the developed composite membranes are promising candidates for the applications of fuel cell technology.
Impaired consciousness in epilepsy has a significant negative impact on patients' quality of life yet is difficult to study objectively. Here, we develop an improved prospective Responsiveness in Epilepsy Scale-II (RES-II) and report initial results compared with the earlier version of the scale (RES). The RES-II is simpler to administer and includes both verbal and non-verbal test items. We evaluated 75 seizures (24 patients) with RES and 34 seizures (11 patients) with RES-II based on video-EEG review. The error rate per seizure by test administrators improved markedly from a mean of 2.01±0.04 with RES to 0.24±0.11 with RES-II. Performance during focal seizures showed a bimodal distribution, corresponding to the traditional complex partial vs. simple partial seizure classification. We conclude that RES-II has improved accuracy and testing efficiency compared with the original RES. Prospective objective testing will ultimately lead to a better understanding of the mechanisms of impaired consciousness in epilepsy.
Herein we report on the hydrothermal synthesis of niobium pentoxide on carbide-derived carbon (Nb2O5/CDC) with a layered structure. The presence of phenylphosphonic acid guides the deposition during preparation, leading to the formation of amorphous Nb2O5 particles which are 4–10 nm in diameter and homogeneously distributed on the CDC framework. Electrochemical testing of the Nb2O5/CDC electrode indicated that the highest capacitance and Coulombic efficiency occurred using an electrolyte comprised of 1 M lithium perchlorate in ethylene carbonate/dimethyl carbonate. Subsequent heat treatment of Nb2O5/CDC in CO2 environment led to crystallization of the Nb2O5, allowing reversible Li+ intercalation/de-intercalation. For sweep rates corresponding to charging and discharging in under 3 min, a volumetric charge of 180 C cm−3 and Coulombic efficiency of 99.2% were attained.
Li2MSiO4 (M = Mn, Fe, Co, Ni, et al.) has received great attention because of the theoretical possibility to reversibly deintercalate two Li+ ions from the structure. However, the silicates still suffer from low electronic conductivity, sluggish lithium ion diffusion and structural instability upon deep cycling. In order to solve these problems, a “hard-soft” templating method has been developed to synthesize three-dimensionally ordered macroporous (3DOM) Li2FeSiO4/C composites. The 3DOM Li2FeSiO4/C composites show a high reversible capacity (239 mAh g−1) with ∼1.50 lithium ion insertion/extraction, a capacity retention of nearly 100% after 420 cycles and excellent rate capability. The enhanced electrochemical performance is ascribed to the interconnected carbon framework that improves the electronic conductivity and the 3DOM structure that offers short Li ion diffusion pathways and restrains volumetric changes.
Solid polymer electrolytes containing phosphotungstic acid (PWA) and/or silicotungstic acid (SiWA) in polyvinyl alcohol (PVA) were investigated for their proton conductivities. Enhanced conductivity was obtained when mixing PWA and SiWA at equal ratio. This polymer electrolyte was found viable for electrochemical capacitors. Thermal and structural analyses were conducted with DSC, XRD, and FTIR. The polymer electrolyte exhibited a different structure and different thermal properties from its respective components. The polymer electrolyte retained its original Keggin structure but contained crystallized protonated water in the form of H5O2 +. The protonated water may contribute to the proton conductivity of the polymer electrolyte.
The thermal stability of the layered oxide LiNi1/3Mn1/3Co1/3O2 and its delithiated product is studied by a combination of X-ray and electron diffraction, TEM imaging and magnetic measurements. Diffraction shows that a small fraction of the layered material converts to spinel phase following delithiation. More spinel phase is observed after thermal annealing. The morphology of the particle changes upon thermal annealing of delithiated materials. The selected area electron diffraction and the magnetic measurement results confirm the presence of Ni+2/Li+ disorder in the delithiated material, which increases upon thermal ageing. The oxidation states of the transition metal ions were determined from magnetic data. It is shown that the charge balance due to removal of Li+ is maintained through oxidation of Ni+2 and that the oxidation states remain stable during subsequent annealing. No antiferromagnetic ordering or crystallographic in plane ordering of transition metal ions is observed. These results clearly describe the thermal degradation of Li x Ni1/3Mn1/3Co1/3O2 (x ≤ 1) occur through the significant microstructural changes.
Neutral chloride-based electrolyte and directly grown manganese oxide on carbon paper are used as the electrolyte and air cathode respectively for rechargeable Zn-air batteries. Oxygen reduction and oxygen evolution reactions on manganese oxide show dependence of activities on the pH of the electrolyte. Zn-air batteries with chloride-based electrolyte and manganese oxide catalyst exhibit satisfactory voltage profile (discharge and charge voltage of 1 and 2 V at 1 mA cm−2) and excellent cycling stability (≈90 days of continuous cycle test), which is attributed to the reduced carbon corrosion on the air cathode and decreased carbonation in neutral electrolyte. This work describes a robust electrolyte system that improves the cycle life of rechargeable Zn-air batteries.
Wood–plastic composites (WPCs) are a form of composite combining wood-based elements with polymers. The processes for manufacturing WPCs include extrusion, injection molding, and compression molding or thermoforming (pressing). Newer manufacturing processes for WPCs include additive manufacturing via fused layer modeling and laser sintering. An important constraint for polymers used in WPCs is requiring process conditions (melt temperature, pressure) that will not thermally degrade the wood filler. Wood degrades around 220 °C; thus, general-purpose polymers like polyethylene and poly vinyl chloride are typically used for manufacturing WPCs. Wood fibers are inherently hydrophilic because of the hydroxyl groups contained in the cellulose and hemicellulose molecular chains. Thus, modification of the wood fiber via chemical or physical treatments is very critical to making improved WPCs. The most abundant profiles made from wood–plastic composites are boards or lumber used in outdoor decking applications. Although early WPC products were mainly extruded for profiled sections, nowadays, many injected parts made of WPC are being introduced for various industries, including electrical casings, packaging, daily living supplies, and civil engineering applications. Mold and mildew and color fading of WPCs tend to be the durability issues of prime importance for WPCs. Most recent research on WPC durability focuses on studies to better understand the mechanisms contributing to various degradation issues as well as methods to improve durability. Most WPC products in the USA are utilized in building materials with few exceptions for residential and commercial building applications, which means that building codes are the most important national rules for the WPC manufacturers. New developments are being made especially in the area of nano additives for WPCs including nanocellulose. Recently, the trend of patent registrations for WPCs has shifted to new products or applications instead of the materials itself.
Li1.2(Mn0.32Ni0.32Fe0.16)O2 (LMNFO) nanoparticles with and without a chelating agent (adipic acid) were synthesized by sol–gel method. The supercapacitive behaviors of the synthesized materials as a cathode are evaluated with activated carbon (AC) as the anode in a hybrid supercapacitor (HSC) configuration utilizing a non-aqueous electrolyte. The structural, morphological and electrochemical features of the prepared materials are investigated using X-ray diffraction, scanning electron microscopy and cyclic voltammetry (CV) and charge–discharge studies, respectively. The results demonstrated that the LMNFO nanoparticles prepared with the chelating agent, adipic acid (AA), delivered an enhanced specific discharge capacitance (86Fg−1) and better cycling stability than the native compound. The CV studies also revealed the same conclusions, based on the stronger current response observed during various scan rates between 0 and 3V. Moreover, the AA-LMNFO/AC cell delivered maximum energy and power densities of 36Whkg−1 and 1.67Wkg−1, respectively, with a columbic efficiency of over 99% and excellent rate performance.
The study of the effect of stress on both combatants physiological and anatomical systems have been poor studied in the specific literature. The present research aimed to study the effect of combat stress in strength manifestations of leg flexor-extensor muscles and the anaerobic metabolism of soldiers. Before and after asymmetrical combat simulation were analyzed parameters of blood lactate concentration, explosive leg strength manifestation and contractile capacity of leg muscle in 186 professional soldiers. Results showed a significant increase (p < 0.05) in blood lactate values (2.23 ± 0.95 vs 7.47 ± 3.67 mmol/L), explosive leg strength (Squat Jump 0.31 ± 0.06 vs 0.35 ± 0.07 m, Countermovement Jump 0.33 ± 0.07 vs 0.36 ± 0.07 m, Abalakov Jump 0.39 ± 0.08 vs 0.41 ± 0.09 m), and a significant decrease of the elastic capacity (0.022 ± 0.04 vs 0.021 ± 0.04) and recruitment and muscle synchronization capability (0.028 ± 0.04 vs 0.026 ± 0.04). This data suggest that combat stress increases the leg strength manifestation despite the significantly increase of muscle acidosis after a combat simulation. This result is probably due to the high activation of the fight-flight system of soldiers which increases the organic response of soldiers and that can compensate the prejudicial effect of acidosis in muscle contraction. These results could be used by officers to improve specific training programs and to improve planning and election of equipment and material for the development of different missions in current theaters of operations.
A lithium sulfide-reduced graphene oxide nanocomposite (Li2S-rGO) was synthesized and evaluated as the cathode material and Li source for the assembly of Li-S batteries. The composite, with a unique 3-D pocket structure, was synthesized by a combination of facile solution chemistry and thermal treatment. The as-prepared Li2S-rGO nanocomposites were characterized by X-ray photoelectron spectroscopy, X-ray diffraction and scanning electron microscopy, which showed 20–40 nm Li2S particles homogeneously dispersed between reduced graphene oxide sheets. Li2S contents as high as ∼66% could be obtained. When used with an electrolyte containing LiNO3 and polysulfide, the Li2S-rGO nanocomposites exhibited a high initial capacity of 982 mAh g−1 Li2S. However, there was noticeable capacity fade in subsequent cycles, probably due to polysulfide dissolution and the shuttle mechanism, but a capacity of 315 mAh g−1 could still be obtained after 100 cycles, with 90–95% coulomb efficiency. The effect of polysulfide additive in the electrolyte on the activation of Li2S in the first delithiation step was discussed.
The conductivity aging and thermal stability of poly(N-methylaniline) are reported. Poly(N-methylaniline) doped with chloride ion was electrochemically synthesized. The conductivity data obtained in the temperature range between 118 and 483K are analysed by Arrhenius and Mott models to elucidate the conduction mechanism. The thermal degradation of both doped and dedoped samples of poly(N-methylaniline) in air and nitrogen atmosphere has been followed using thermogravimetric and differential thermal analysis techniques. The polymer is heat-aged at various temperatures and the aged samples are analysed by FT-IR, SEM and XRD. The thermogravimetric data are further analysed by three different methods: Horowitz and Metzger [Anal. Chem. 35 (1963) 1464], Coats and Redfern [Nature 201 (1964) 68], Chan et al. [Synth. Met. 31 (1989) 95] to evaluate the energy of activation. The applicability of the three methods for the evaluation of kinetic parameters is discussed.
Personal exposure sampling provides the most accurate and representative assessment of exposure to a pollutant, but only if measures are implemented to minimize exposure misclassification and reduce confounders that may cause misinterpretation of the collected data. Poor compliance with personal sampler wearing protocols can create positive or negative biases in the reported exposure concentrations, depending on proximity of the participant or the personal sampler to the pollutant source when the monitor was not worn as instructed. This paper presents an initial quantitative examination of personal exposure monitor wearing protocol compliance during a longitudinal particulate matter personal exposure monitoring study of senior citizens of compromise health in North Carolina. Wearing compliance varied between participants because of gender or employment status, but not longitudinally or between cohorts. A minimum waking wearing compliance threshold, 0.4 for this study of senior citizens, is suggested to define when personal exposure measurements are representative of a participant's exposure. The ability to define a minimum threshold indicates data weighting techniques may be used to estimate a participant's exposure assuming perfect protocol compliance.
The paper presents first the theoretical foundations used to develop a pre-experimental version of a questionnaire on relationship to work, and then the four stages of its initial validation leading to an experimental version. These stages included: (1) Defining the dimensions and sub-dimensions of the relationship to work concept; (2) Operationalizing the dimensions and sub-dimensions and creating the items; (3) Verifying the face and content validity and developing the pre-experimental questionnaire; (4) Testing the pre-experimental questionnaire with 550 workers and 538 students, assessing its psychometric properties and elaborating the experimental questionnaire.
The effect of partial substitution of Al and Mo for Ni on the structure and electrochemical properties of the La0.7Mg0.3Ni3− x (Al0.5Mo0.5) x (x =0–0.4) hydrogen storage alloys have been investigated systematically. The result of X-ray powder diffraction (XRD) and Rietveld analysis show that all the alloys consist of the La(La, Mg)2Ni9 phase and the LaNi5 phase. Meanwhile, the lattice parameter and the cell volume of both the La(La, Mg)2Ni9 phase and the LaNi5 phase increase with increasing Al and Mo contents in the alloys. The pressure composition isotherms curves indicate that the hydrogen storage capacity first increases and then decreases with increasing x. The electrochemical measurements show that the maximum discharge capacity of the alloy electrodes first increases from 343.3 (x =0) to 377.6mAh/g (x =0.3) and then decreases to 350.4mAh/g (x =0.4). Moreover, the high rate dischargeability (HRD) and the exchange current density of the alloy electrodes decrease first and then increases with the increase of x in the alloys. The hydrogen diffusion coefficient increases with increasing Al and Mo content and thus increases the low temperature dischargeability (LTD) of the alloy electrodes.
The coated separator was prepared by coating poly(vinyl acetate) (PVAc) on the surface of the novel separator based on poly(vinylidene fluoride) (PVdF) and polyethylene (PE) non-woven matrix. The ionic conductivity of the coated separator was 1.1×10−3 Scm−1 at 25°C, a little higher than that of bare separator. The coated separator showed smoother surface morphology and better adhesion property toward electrodes, and thereby it resulted in lower total resistance than the bare separator. The discharge capacity of the unit cell with coated separator at C/2 rate was maintained at about 84% of the theoretical capacity, which is quite higher than that of the unit cell with the bare separator.