batterydata/paper-abstracts huggingface dataset:
Commercial battery cells with Li4Ti5O12 negative electrode and composite metal oxide positive electrode have been analyzed with respect to aging mechanisms. Electrochemical impedance spectroscopy (EIS), differential capacity analysis (dQ/dV), differential voltage analysis (dV/dQ) and scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDX) were used to identify different ageing mechanisms such as lithium inventory loss, loss of active electrode material and surface film growth. The active material of the positive electrode was also examined by X-ray diffraction (XRD). Aging mechanisms were studied for both calendar-aged and cycle-aged cells. Data from half cells prepared from post mortem harvested electrode material, using lithium foil as negative electrode and pouch material as encapsulation, were used as reference to full cell data. Electrochemical analysis of full and half cells combined with material analysis showed to be a powerful method to identify aging mechanisms in this type of commercial cells. The calendar-aged cell showed insignificant aging while the cycle-aged cell showed noticeable loss of positive electrode active material and loss of cyclable lithium, but only minor loss of negative electrode active material. The results imply that Li4Ti5O12 negative electrode material is a good alternative to other materials if high energy density is not the primary goal.
Four types of orthorhombic olivine LiMPO4 (M:Co, Fe, Ni and Mn) were investigated as high-voltage cathode active materials for lithium secondary batteries. LiCoPO4 exhibited the highest 4.8V discharge plateau of 100mAh/g versus Li/Li+ after initial charging to 5.1V and its energy density was comparable to that of layered rocksalt LiCoO2 (120 mAh/g×4 V=480 mWh/g). In contrast, the open circuit voltage profile of LiFePO4 was 160mAh/g on the 3V plateau. The Co2+ state in LiCoPO4 was confirmed using HRXRF.
Polyethylene oxide–NaClO3 composite have been prepared by solution casting technique with different weight percentages as a polymer electrolyte for battery application. The prepared composites were characterized by various tools like XRD, FTIR and SEM. The X-ray diffraction analysis shows the complexation of polymer with salt and existence of both crystalline and amorphous phases. From FTIR spectra confirms the formation of PEO–NaClO3 composites. SEM images shows the grains are highly agglomerated and its average size increases with increase in salt ratio. Frequency dependence of dielectric property and ac electrical conductivity of polymer electrolytes were studied within the frequency range of 50Hz to 5MHz using complex impedance analysis technique. Ionic conductivity follows Arrhenius type behavior as a function of temperature. The fabricated cell of 25wt.% of PEO–NaClO3 composites generated high current of 1.79A.
Objective Olfactory deficits in schizophrenia patients have been suggested to reflect medial temporal and/or prefrontal brain abnormalities. In this study, we examined the relationship between different olfactory functions and volumes of the hippocampus–amygdala complex (HAC) and the orbitofrontal brain region using magnetic resonance imaging (MRI). Methods Thirty-three young men with schizophrenia (DSM-IV) and 40 healthy controls performed unirhinal olfactory assessment including the main olfactory functions (threshold, discrimination, and identification), and odor judgements (intensity, edibility, familiarity, and pleasantness). Volumes of regions in the medial temporal lobe (hippocampus and amygdala) and the prefrontal region (orbitofrontal gray and white matter) were measured on MRI scans. Results Compared with controls, patients showed bilaterally impaired thresholds, quality discrimination and identification, as well as edibility judgements. Olfactory deficits were not attributable to smoking, premorbid intelligence, or impaired thresholds. Relative to controls, patients had bilateral reduced hippocampus and amygdala volumes. In patients, smaller hippocampus volumes were associated with poorer olfactory discrimination ability. Conclusions Olfactory deficits in schizophrenia appear to be associated with morphometric abnormalities in the medial temporal rather than the orbitofrontal region (OFR). These results indicate that olfactory quality discrimination deficits are related to structural hippocampus abnormalities. Future studies of genetic and behavioral high-risk samples seem warranted.
This paper describes a cooling strategy development method for an air cooled battery pack with lithium-ion pouch cells used in a hybrid electric vehicle (HEV). The challenges associated with the temperature uniformity across the battery pack, the temperature uniformity within each individual lithium-ion pouch cell, and the cooling efficiency of the battery pack are addressed. Initially, a three-dimensional battery pack thermal model developed based on simplified electrode theory is correlated to physical test data. An analytical design of experiments (DOE) approach using Optimal Latin-hypercube technique is then developed by incorporating a DOE design model, the correlated battery pack thermal model, and a morphing model. Analytical DOE studies are performed to examine the effects of cooling strategies including geometries of the cooling duct, cooling channel, cooling plate, and corrugation on battery pack thermal behavior and to identify the design concept of an air cooled battery pack to maximize its durability and its driving range.
Meniscal tears often accompany knee osteoarthritis, a disabling condition affecting 14 million individuals in the United States. While several randomized controlled trials have compared physical therapy to surgery for individuals with knee pain, meniscal tear, and osteoarthritic changes (determined via radiographs or magnetic resonance imaging), no trial has evaluated the efficacy of physical therapy alone in these subjects.
A series of pitch modified hard carbons was prepared using coal-tar pitch and phenolic resin as carbon precursors. The effects of the amount of the soft carbon from pitch precursor, varying from 0wt% to 40wt%, and heat-treatment temperature in the range from 900°C to 1800°C, on their electrochemical performance were systemically studied, including the reversible capacity, coulombic efficiency in the first cycle, the rate capability and cycling stability. Under the optimal condition, the carbon material obtained at 1200°C with 30wt% soft carbon as negative material for lithium-ion batteries exhibits a reversible capacity of about 290mAhg−1 at a constant current density of 0.5mAcm−2 with excellent rate capability and cycling stability.
The purpose of this study is focused on gender differences in traffic risk assuming and short term memory related to traffic situations. Method: They were applied on a sample of 60 subjects, 30 men and 30 women in a psychology lab of a driving school. Instruments: ATATVT measuring short term memory in driving situation and WRBTV mesuring risk asuming tendencies in traffic situation (Vienna Test System, 2012). The results didn’t confirm the statistical hypotheses in the way that male subjects evidence higher or lower tendences in assuming the risk in traffic situation than female subjects (p>0.05).
The mechanism of thermal transport at solid interfaces depends on many parameters in particular the quality of the interface. Here, the authors compare experimental and calculated thermal boundary conductance across high-quality harmonic-matched epitaxial Al-sapphire interfaces and find that elastic phonon processes dominate the ultra-clean interfaces.
A wide range of outcomes have been assessed in trials of interventions for carpal tunnel syndrome (CTS), however there appears to be little consensus on what constitutes the most relevant outcomes. The purpose of this systematic review was to identify the outcomes assessed in randomized clinical trials of surgical interventions for CTS and to compare these to the concepts contained in the International Classification of Functioning, Disability and Health (ICF).
In this paper, an adaptive neuro-fuzzy inference system (ANFIS) was proposed for condition monitoring and fault diagnosis of an automotive generator. Conventional fault indication of an automotive generator generally uses an indicator to inform the driver when the charging system is malfunctioning. Unfortunately, the charge indicator only shows if the generator is normal or in a fault condition. In the present study, an automotive generator fault diagnosis system was developed for fault classification of different fault conditions. The condition monitoring system consists of feature extraction using discrete wavelet analysis to reduce the complexity of the feature vectors with classification using the artificial neural network technique. In the generator output signal classification, the ANFIS is used to classify and compare the synthetic fault types in an experimental engine platform under various engine operating conditions. The experimental results pointed out the proposed condition monitoring and fault diagnosis system has potential in fault diagnosis of the automotive generator.
Under over-increasing demand of advanced lithium-ion batteries (LIBs) for long-range electric vehicles (EVs), high-capacity transition metal oxide (TMO) negative electrodes for LIBs are thought as potential substitutes of traditional graphite anodes. A major barrier for TMO anodes is volumetric expansion during lithiation processes, leading to active material pulverization and falling off current collectors, which seriously deteriorates capacity retention. Herein, apart from conventional mechanical degradation, another capacity fading mechanism is revealed. Furthermore, the understanding is supported by an interesting cycling property. Firstly, NiCo2O4 with designed morphologies of nanoplates and microspheres are studied for the initial (de)lithiation and prolonged cycles. The morphology changes indicate solid electrolyte interphase (SEI) layer accumulating on the surface of electrodes and impeding the contact and reactions between lithium and active materials with a result of severe capacity loss. It can be understood as SEI layer insulating NiCo2O4, and if SEI film appropriately changes, high capacities can recovery. This conjecture is confirmed by following research of NiCo2O4 nanoparticles with amazing cycling performance prepared by a facile water-bath method. As LIB anodes, NiCo2O4 nanoparticles exhibit capacities of 1144 mAh g−1 at the initial discharging, 230 mAh g−1 at the 100th cycle and 661 mAh g−1 at the 500th cycle. The corresponding coulombic efficiency is of 73.1%, 98.4% and 99.5%, respectively. By TEM characterization in combination with electrochemical analysis, size-dependent SEI layer reactivation (from thick and unstable to thin and stable) is a key role on the dramatic capacity recovery.
The lithium-ion battery anode performance of graphites with and without high amounts of rhombohedral phase in the structure has been investigated. A main outcome was that in addition to possible graphite bulk structure effects, there are also strong influences of the graphite surface and the graphite “sub-surface” (part of the graphite bulk at the border of the particle near the surface) on the solid electrolyte interphase (SEI) formation process and on the tendency to solvent co-intercalation into graphite. Using transmission electron microscopy with atomic resolution, we indeed could determine unique and also different surface and “sub-surface” morphologies for the two graphites. In case of the graphite without rhombohedral phase, unique convoluted graphene layers could be determined at the prismatic surfaces; in case of the graphite with a high rhombohedral phase content a strongly disordered, approximately 1nm thick “sub-surface” layer could be determined. The anode performance depends primarily on these surface and “sub-surface” graphite properties and the used electrolytes. The differences in the “sub-surface” layer structure have a most significant influence on the performance in an ethylene carbonate/dimethyl carbonate electrolyte. The differences in surface structure and morphology are considered to have the highest impact in a propylene carbonate/ethylene sulfite-based electrolyte. For ethylene carbonate/diethyl carbonate electrolyte, the performance differences are small so that no strong dependence on surface or “sub-surface” structures could be observed.
Among different printing techniques, direct ink writing is commonly used to fabricate 3D battery and supercapacitor electrodes. The major advantages of using the direct ink writing include effectively building 3D structure for energy storage devices and providing higher power density and higher energy density than traditional techniques due to the increased surface area of electrode. Nevertheless, direct ink writing has high standards for the printing inks, which requires high viscosity, high yield stress under shear and compression, and well-controlled viscoelasticity. Recently, a number of 3D-printed energy storage devices have been reported, and it is very important to understand the printing process and the ink preparation process for further material design and technology development. We discussed current progress of direct ink writing technologies by using various electrode materials including carbon nanotube-based material, graphene-based material, LTO (Li4Ti5O12), LFP (LiFePO4), LiMn1-xFexPO4, and Zn-based metallic oxide. Based on achieve electrochemical performance, these 3D-printed devices deliver performance comparable to the energy storage device fabricated using traditional methods still leaving large room for further improvement. Finally, perspectives are provided on the potential future direction of 3D printing for all solid-state electrochemical energy storage devices.
We describe the mechanism of cobalt and ligand binding on nanotextured poly(chloro-p-xylylene) (PPX) films as supports for catalytic release of H2 from alkaline aqueous solutions of sodium borohydride. Cobalt catalysts are prepared on nanotextured PPX substrates via electroless plating using a Sn-free Pd(II) colloid with adsorbed pyridine ligand as an adhesion promoter. Gas physisorption studies on PPX, using N2 and CO2 as probe gases, indicate the presence of micropores (∼1 to 2nm width) responsible for the adsorption and non-covalent stabilization of pyridine molecules on the nanotextured surface. The strongly adsorbed pyridine molecules promote Co adhesion onto the PPX surface during subsequent electroless deposition, thereby retaining the metal's catalytic activity for H2 evolution even after multiple reaction cycles. In contrast, conventionally deposited PPX is devoid of any nanotexture and contains fewer micropores capable of stabilizing pyridine adsorption, resulting in poor metallization and catalytic activity for H2 evolution. We also demonstrate the effect of patterning the PPX substrate as a means to further improve the activity of the Co catalyst to achieve H2 evolution rates comparable to those obtained using precious metal catalysts.
Reduced graphene oxide (RGO)/nickel cobaltite (NiCo2O4) nanoflake composites were prepared by combining in situ assembling and subsequent thermal treatment. The RGO/NiCo2O4 composites were characterized by scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, X-ray powder diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, nitrogen adsorption/desorption isotherms and thermogravimetric analysis. Cyclic voltammetry and chronopotentiometry measurements were performed to investigate the electrochemical properties of the composites. Superior performances were achieved with high specific capacitance of 1693Fg−1 at 1Ag−1, good rate capability (67.6% capacity retention at 16Ag−1) and long-term cyclability (only 9.2% loss after 2000 cycles). The binary redox couples of Ni2+/Ni3+ and Co2+/Co3+, ultrathin nanoflake structure, together with the high electrical conductivity of RGO to the outside current collectors are responsible for the excellent electrochemical performances of the RGO/NiCo2O4 composite, thus suggesting its potential application as an effective electrode material for supercapacitors.
Wadsley–Roth phase Li x Nb9PO25 has been studied as a potential candidate for anode material of Li-ion batteries. Its crystal structure, which consists of ReO3-type blocks of NbO6 octahedra connected with PO4 tetrahedra, provides a good stability and performance during Li+ insertion/removal. Li-ion chemical diffusion coefficient (D chem) in Li x Nb9PO25 was determined by means of potentiostatic intermittent titration technique and electrochemical impedance spectroscopy. Different data treatments (classical Warburg equation or the model of an electrode system with ohmic potential drop and/or slow kinetics of the interfacial Li+ ion transfer across the electrode/electrolyte interface) were used for calculation of D chem of the Li ion inside this material; their applicability is discussed in the article. D chem changes with the Li-ion doping degree, x, in Li x Nb9PO25 and has a sharp minimum near the two-phase region at appr. 1.7V vs. Li+/Li. These values of D chem in Li x Nb9PO25 (∼10−9–10−11 cm2 s−1) were found to be in average noticeably higher than in the widely studied anode material, Li4Ti5O12.
In a modern economy, the investment in human capital by firms is crucial to foster technological adoption and foster productivity growth. This paper analyzes the correlation between firm size and the investment in job training by employers. Using a large firm level data set across 99 developing countries, we show that a strong and positive correlation in the investment in job training and firm size is a robust statistical finding both within and across countries with very different institutions and levels of development. Even though we cannot fully disentangle correlation from causality, we show that the size-training gap is not fully explained by differences across firms in market imperfections or institutional failures impeding the development of smaller firms. Our findings call for the urgency of collecting better panel data sets to understand how cost-effective are on-the-job training programs in fostering firm productivity and growth in developing countries.
Personal sun exposure measurements provide important information to guide the development of sun awareness and disease prevention campaigns. We assess the scaling properties of personal ultraviolet radiation (pUVR) sun exposure measurements using the wavelet transform (WT) spectral analysis to process long-range, high-frequency personal recordings collected by electronic UVR dosimeters designed to measure erythemal UVR exposure. We analysed the sun exposure recordings of school children, farmers, marathon runners and outdoor workers in South Africa, and construction workers and work site supervisors in New Zealand. We found scaling behaviour in all the analysed pUVR data sets. We found that the observed scaling changes from uncorrelated to long-range correlated with increasing duration of sun exposure. Peaks in the WT spectra that we found suggest the existence of characteristic times in sun exposure behaviour that were to some extent universal across our data set. Our study also showed that WT measures enable group classification, as well as distinction between individual UVR exposures, otherwise unattainable by conventional statistical methods.
Carbon-coated LiFePO4 (C-LiFePO4) with micron particle size (6μm) and high tap density (1.6gcm−3) was prepared from spherical FePO4·2H2O powder via the co-precipitation method. The C-LiFePO4 powder was calcined at temperatures between 650 and 800°C. The 6μm C-LiFePO4 prepared at 800°C exhibited an excellent rate capability, delivering 150mAhg−1 on discharge at the 0.1C-rate and 108mAhg−1 at the 5C-rate. The volumetric capacity of the 6μm C-LiFePO4 corresponded to 225mAhcm−3, since the large secondary particles (6μm) C-LiFePO4 sufficiently allowed tight packing of the particles. The 6μm C-LiFePO4 powder with high tap density makes an attractive positive electrode candidate for lithium-ion batteries designed for high energy density.
Iron was substituted for Ni in LiNi0.8Co0.2O2 in order to enhance its electrochemical properties such as cycle life and rate capability. LiNi0.8−x Fe x Co0.2O2 (0≤x≤0.1) was synthesized in flowing oxygen for 12–48h at 650–800°C, and its structural and electrochemical properties were characterized with X-ray diffraction (XRD), cyclic voltammetry (CV) and charge–discharge tests. The XRD patterns of LiNi0.8−x Fe x Co0.2O2 showed that the α-NaFeO2 type layered structure was maintained up to x=0.1. As Fe was substituted for Ni up to x=0.05, the rate capability of LiNi0.8−x Fe x Co0.2O2 was improved. LiNi0.75Fe0.05Co0.2O2 showed better cycle stability than LiNi0.8Co0.2O2. XRD measurements indicated that the lattice of LiNi0.75Fe0.05Co0.2O2 expanded less than that of LiNi0.8Co0.2O2 when the lithium was de-intercalated. CV curves of LiNi0.8−x Fe x Co0.2O2 showed current peaks, which are related to the phase transitions, diminished with Fe substitution during charging and discharging owing to the decrease of Ni3+. Consequently, the improved cycle stability of LiNi0.75Fe0.05Co0.2O2 may be attributed to the decrease of phase transition.
This paper develops and analyzes a mathematical model for the novel system of a redox flow lithium ion battery (RFLB). In essence, the model accounts for conservation of charge in the cell and conservation of species –redox shuttle molecules –in both the cell and tanks. In order to gain further understanding of the system involving multiple redox species, the steady-state conservation of charge in the cell is analyzed. Such an analysis allows for a considerable reduction in model complexity, resulting in a semi-analytical model. The results of the semi-analytical model are verified against those of full model and validated with experimental charge-discharge curves. Overall, good agreement is found that allows the model to explain the system behavior, particularly the multiple voltage regimes and the corresponding electrochemical and chemical reactions taking place. An operational strategy for improving the battery capacity is identified.
Reversible electrochemical cells can operate in both fuel cell and electrolysis modes to interconvert between chemical and electrical energy. Here, Duan et al. design a reversible protonic ceramic electrochemical cell that operates stably at 500–600 °C, with high Faradaic and round-trip efficiencies, by minimizing electronic leakage.
Individuals with schizophrenia show magnocellular visual pathway abnormalities similar to those described in dyslexia, predicting that reading disturbance should be a common concomitant of schizophrenia. To date, however, reading deficits have not been well established, and, in fact, reading is often thought to be normal in schizophrenia based upon results of tests such as the WRAT, which evaluate single word reading. This study evaluated “real world” reading ability in schizophrenia, relative to functioning of the magnocellular visual pathway. Standardized psychoeducational reading tests and contrast sensitivity measures were administered to 19 patients and 10 controls. Analyses of between group differences were further refined by classification of participants into reading vs. non-reading impaired groups using a priori and derived theoretical models. Patients with schizophrenia, as a group, showed highly significant impairments in reading (p <0.04–p <0.001), with particular deficits on tests of rate, comprehension and phonological awareness. Between 21% and 63% of patients met criteria for dyslexia depending upon diagnostic model vs. 0–20% of the controls. The degree of deficit correlated significantly with independent measures of magnocellular dysfunction. Reading impairment in schizophrenia reaches the level of dyslexia and is associated with compromised magnocellular processing as hypothesized. Findings related to symptoms, functioning and recommendations for reading ability assessment are discussed.