batterydata/paper-abstracts huggingface dataset:
This paper gives insight to the physical processes taking part during the two-phase transition in lithium intercalation compounds. The behaviour of olivine based electrodes is in the special focus of this work. These electrodes exhibit phase juxtaposition within the electrode particles over a wide state of charge (SOC) range. Measurements were made to explore effects related to the formation of distinct phase sequences within the particles. Asymmetric charge characteristics, a load history dependency of the internal resistance and a voltage effect related to the disappearance of certain phase regions (the later on called vanishing phase effect) were identified. Moreover, these measurements give evidence to the existence of stable phase regions inside the electrode active material. An intuitive model is given to visualize the phase regions within spherical olivine particles. Therefore an analytical approach is developed in order to take the geometry of the particles, the ion permeability as well as the size distribution of the particles in consideration. According to the developed approach and the obtained measurement results, an enhanced cell equivalent electrical circuit is evaluated, considering phase shell development effects.
Grid-connected microgrids (MG) can offer significant benefits to electricity systems by improving the security of energy supply with clean renewable energy sources. Unlocking these benefits requires designing suitable business models that can capture the value of MGs and that help removing barriers to their uptake. In this work, we evaluate the profitability and self-sufficiency of optimally designed MGs for new proposed business models. The business models are tested in seventeen different geographical locations which offer a vast diversity of renewable resources, seasonal climatic variability and electricity tariffs. Both Net Billing and Net Metering schemes are tested, for both single-dwelling and community residential customers. Electricity tariffs include both energy volumetric and peak demand charges. We model the optimal sizing and energy management of the MGs by minimizing the total customer electricity costs. The generation mix of the MGs is the result of a bilevel optimization which take into account renewable resources and costs, diesel prices and tariffs. MGs can potentially be comprised by solar PV, wind and diesel generation, together with battery storage systems and demand response resources. We find significant levels of self-sufficiency based on solar sources across the country, and also wind power in some specific locations. The community business model, case which includes the peak demand charges, is generally more profitable than the case of single-dwellings. This shows that the MGs are effective at reducing the peak demand charge of a residential electricity bill. We therefore recommend the further promotion of community energy arrangements as a key way to improve the current very slow uptake of distributed generation in developing countries.
Background Electroconvulsive therapy (ECT) is an effective alternative for pharmacotherapy in treatment-resistant depressive patients, but the side effects limit its use. Transcranial magnetic stimulation (TMS) has been proposed as a refined alternative, but most studies do not indicate that TMS is as effective as ECT for severe depression. Objective We propose that the limited effectiveness of standard TMS resides in its superficial effect on the cortex, although much of the pathophysiology of depression is associated with deeper and larger brain regions implicated in the reward system. Herein, we tested the effectiveness and safety of a novel TMS coil, the “H-coil,” which enables direct stimulation of deeper brain regions, at the expense of focality. Methods We have studied the antidepressant and cognitive effects induced by 4 weeks of high-frequency (20 Hz) repeated deep TMS (DTMS) over the prefrontal cortex (PFC) of 65 medication-free depressive patients, who have failed to benefit from prior medications. Patients were randomly assigned to various treatment configurations, differing in stimulation intensity and laterality. Effects were assessed by the 24-item Hamilton depression rating scale (HDRS-24) and several secondary outcome measures. Results A significant improvement in HDRS scores was found when high, but not low, stimulation intensity was used. Several cognitive improvements were evident, and no treatment-related serious adverse events were observed. Conclusions DTMS over the PFC was found safe and effective in alleviating depression. The results accentuate the significance of deep, high-intensity stimulation over low, and serve as the first study to indicate the potential of DTMS in psychiatric and neurologic disorders.
Although antibiotics have been increasingly used and detected in natural samples, their ecotoxicological effects on aquatic wildlife are not yet extensively studied. Considering the environmental threat posed by the biological activity of antibiotics it is quite relevant to assess the resulting impact, especially on sub-lethal endpoints. As such, this study evaluated the effects of ciprofloxacin on Pseudokirchneriella subcapitata and Lemna minor growth, on the survival and reproduction of Daphnia magna and on Gambusia holbrooki survival. The risks associated with ciprofloxacin effects on non-target organisms were quantified through the calculation of the PEC/PNEC ratio. Overall, the toxicity values obtained (at the mg L−1 level) were higher than the environmental concentrations. P. subcapitata and L. minor were more sensitive under short-term exposures than D. magna and G. holbrooki. No acute toxicity was observed for fish. The chronic assay with D. magna evidenced that long term exposures to lower concentrations of this antibiotic induced impairments on its life-history parameters. Such outcome may pre-empt potential damages on the long-term maintenance of natural populations continuously exposed to the input of antibiotics. Indeed, the PEC/PNEC ratios showed that ciprofloxacin represents a risk for the most sensitive aquatic organisms, since the defined threshold of an acceptable risk was considerably surpassed.
Distinctive electronegativity and similar atomic radius for elements of C and N afford their allotropic substances composed of these two elements with excellent photo- and electro-chemical performance for energy conversion. To explore the synergetic roles of allotropic substances, carbon-rich C3N4 (CCN) is in-situ hydrothermally synthesized with the N-doped graphene (NG) grown by chemical vapor deposition (CVD) as the template to prepare the N-doped graphene/carbon-rich C3N4 composite. Compared to the N-doped graphene and carbon-rich C3N4, N-doped graphene/carbon-rich C3N4 composite exhibits the remarkable enhancement of catalytic activities toward hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). Particularly, visible light irradiation can significantly improve the catalytic performance of N-doped graphene/carbon-rich C3N4 toward the above three reactions. Further results confirm that N-doped graphene/carbon-rich C3N4 exhibits the improved electrochemically active surface area (ECSA), light-harvesting ability, effective separation of electron-hole pairs, and interfacial charge transfer as compared to the N-doped graphene and carbon-rich C3N4 which should be originated from the efficient bridging between N-doped graphene and carbon-rich C3N4 layers. Our elucidation facilitates to pave their promising applications in microelectronic devices, wearable devices, photoelectrochemical batteries, sensors and other fields.
Carbon-based electrodes with a bifunctional catalyst are being studied extensively for use in rechargeable metal-air batteries. In this study, the effects of various testing conditions on the electrochemical performance, cyclic lifetime, and degradation mechanism of the electrodes prepared using the bifunctional La0.6Ca0.4CoO3 catalyst mixed with the graphitized Vulcan XC-72 carbon black and polytetrafluoroethylene were evaluated in detail. The electrochemical performance and total cycle life of the electrodes were not noticeably affected by the KOH electrolyte concentration or rest time between the charge/discharge. The charge/discharge current density used for the cyclic test significantly influenced both the total cyclic lifetime and degradation mechanism of the electrode. At the higher current densities (±50 and ± 100 mA/cm2), carbon corrosion led to electrode flooding and the loss of oxygen reduction capability while the oxygen evolution reaction occurring at the catalyst was largely sustained. At a lower current density (±6 mA/cm2), with periodic replacement of electrolyte to avoid carbonate formation in the electrode pores, the loss of the anodic catalytic ability of the bifunctional catalyst presumably via surface oxidation was clearly evident from the increase in oxygen evolution reaction overpotential. With the unchanged electrolyte, the electrode gas transport pore could be blocked by carbonate formation, leading to a decreased catalytic capability of the electrode for oxygen reduction. The failure modes of these electrodes under various cycling conditions were also assessed using impedance spectroscopy and inductively coupled plasma optical emission spectrometry.
As a novel partial substitution and surface modification process, we focused on a step-by-step (double-step) supersonic-wave treatment in a Zn-containing aqueous solution without any heat-treatments, and performed the treatment on LiMn2O4 powder. From XRD measurements, it was demonstrated that the lattice constant of LiMn2O4 decreased slightly by the treatments, indicating a partial substitution of Zn for Mn. It was also suggested by SEM–EDX and XPS that Zn was well dispersed in/on the samples and their surfaces were modified by Zn compounds. Such a partial substitution and surface modification was supported by crystal structure analysis based on the Rietveld method using neutron diffraction. Cycle performance of LiMn2O4 was significantly improved by the step-by-step supersonic-wave treatments. In the processes, it was especially effective for the improvement to apply lower and higher frequencies at the first and second steps, respectively, keeping the power higher. The cathode property improvement was considered due to the partial substitution and the surface coating caused by the step-by-step supersonic-wave treatments. From the investigation on the cathodes and electrolytes after the cycle tests, it was suggested that the crystal structure of LiMn2O4 was stabilized by the treatments.
Objectives To assess daytime cognitive performance, sedation and treatment satisfaction in patients with schizophrenia receiving quetiapine extended release (XR) versus quetiapine immediate release (IR). Methods Phase IV prospective, double-blind, crossover study (NCT01213836). Patients (N=66) with stable schizophrenia, treated with XR or IR before study start, were randomised (1:1) to treatment with XR followed by IR, or IR followed by XR, at the dose received before enrolment (400–750mg). After 10–16days on formulation 1, patients switched to formulation 2. Assessments from three post-dose visits (≥5days following treatment on each formulation) were analysed. Cognitive performance was measured by CogState Cognition testing. Sedation, treatment satisfaction and safety were also assessed. Results 65 patients received treatment (69.2% male; mean age 37.8years). Daytime cognitive functioning was similar for both groups; adjusted mean difference in Attentional Composite Score in XR and IR patients was 0.005 (p=0.907). Patients receiving XR were less sedated than those receiving IR, (Bond–Lader visual analogue scale score, mean [SD]: 23.5 [19.0] vs 28.6 [21.4]); estimated overall treatment difference: 5.2 (95% CI: 2.3, 8.2; p<0.0009). Patients receiving XR reported feeling less sedated than those on IR (Stanford Sleepiness Scale, mean [SD]: 2.4 [0.9] vs 2.6 [1.0]); estimated overall treatment difference: 0.28 (95% CI: 0.12, 0.43; p<0.0008). Patients reported improved overall treatment satisfaction (p=0.0417) and milder side effects (p=0.0035) with XR. Safety profile was similar in both groups. Conclusion Daytime cognitive performance was similar for both groups. XR was associated with less daytime sedation and improved patient satisfaction than IR.
A LiPON–WO3 composite thin film (LPWON) was evaluated for use as a solid electrolyte in solid state electrochromic (EC) devices. LiPO4 and a WO3 (2wt%) composite sputtering target was synthesized by a ball milling process. The LPWON thin films were deposited by RF magnetron sputtering in Ar+N2 and N2 atmospheres. The structural, electrochemical, and optical properties of the LPWON electrolytes were characterized by X-ray diffraction (XRD), UV–visible spectroscopy, and an impedance analyzer. EC mirrors with WO3 (coloring layer), LPWON (solid electrolyte), and stainless steel (mirror electrode) on ITO (transparent electrode) glass were fabricated to analyze the improved EC properties due to the LPWON electrolyte. The LPWON may lead to electrolytes with more stable potential cycle properties.
An issue with conventional non-aqueous Li–O2 battery cathodes that are formed by spraying/brushing/casting/coating carbon black slurries is a lack of sufficiently large pores, vulnerable to clogging by solid discharge products, and hence resulting in a low capacity. In this work, we report a novel cathode structure formed by screen-printing method. This deposition method allows the creation of evenly distributed large pores (∼10 μm). As compared with the cathode formed by slurry-coating method, the cathode formed by the present method increases the battery's capacity by two times. The cyclability is also seen a significant improvement. The improved performance may be attributed to large pores that give more appropriate distributions of discharge products and hence facilitate the transportation of oxygen during cycling.
In comparison with inorganic and dry polymeric materials, conductive polymer hydrogels are promising soft electrode materials due to their unique solid-liquid interface. Nevertheless, the existing hydrogels lack either excellent electrochemical performance or mechanical resilience. Here we report a strategy to overcome this limitation by integrating two types of conducting polymers – polyaniline and PEDOT – through a molecular bridge provided by phytic acid. The acid replaces some of PSS, promoting transformation of PEDOT chains from the benzoic structure to the quinoid structure. The resulting hydrogel consists of a 3D network of PEDOT sheets where PANi are inlaid; it has highly improved mechanical properties in comparison with PEDOT hydrogel due to molecular interactions between PANi and PEDOT. A flexible solid-state supercapacitor based on PEDOT/PANi hydrogel delivered a high volumetric energy density of 0.25 mWh cm−3 at a power density of 107.14 mW cm−3, surpassing many of previously reported solid-state supercapacitors based on PEDOT and hydrogels of other conducting polymers and graphene oxide. This study represents a new direction for the development of conductive polymer composite hydrogels which combine excellent electrochemical performance with mechanical resilience.
Recent development of electrode materials for Li-ion batteries is driven mainly by hybrid nanocomposite structures consisting of Li storage compounds and CNTs. In this study, tin/tinoxide (Sn/SnO2) films and tin/tinoxide/multi walled carbon nanotube (Sn/SnO2/MWCNT) nanocomposites are produced by a two steps process; thermal evaporation and subsequent plasma oxidation as anode materials for Li-ion batteries. The physical, structural, and electrochemical behaviors of the nanocomposite electrodes containing MWCNTs are discussed. The ratio between metallic tin (Sn) and tinoxide (SnO2) is controlled with plasma oxidation time and effects of the ratio are investigated on the structural and electrochemical properties. The greatly enhanced electrochemical performance is mainly due to the morphological stability and reduced diffusion resistance, which are induced by MWCNT core and deposited Sn/SnO2 double phase shell. The outstanding long-term cycling stability is a result of the two layers Sn and SnO2 phases on MWCNTs. The nanoscale Sn/SnO2/MWCNT network provides good electrical conductivity, and the creation of open spaces that buffer a large volume change during the Li-alloying/de-alloying reaction.
A novel autonomous free-fall lander vehicle, with a capability down to 6000m, was deployed off Cape Verde for studies on bioluminescence in the deep sea. The system was equipped with a high-sensitivity Intensified Silicon Intensified Target (ISIT) video camera, a programmable control-recording unit and an acoustic current meter with depth and temperature sensors. The ISIT lander was used in three modes: (1) free falling at 34mmin−1, with the camera looking downwards at a mesh screen, recording impacts of luminescent organisms to obtain a vertical profile down to the abyssal sea floor, sampling at >100ls−1; (2) rotating, with the lander on the sea floor and the camera orienting to the bottom current using a servo-controlled turntable, impacts of luminescent organisms carried by the bottom current onto a mesh screen mounted 0.5m in front of the camera were recorded to estimate abundance in the benthic boundary layer; (3) baited, with the camera focused on a bait placed on the sea floor. Profiles recorded abundance of luminescent organisms as 26.7m−3 at 500–999m depth, decreasing to 1.6m−3 at 2000–2499m and 0.5m−3 between 2500m and the sea floor at 4046m, with no further detectable significant change with depth. Rotator measurements at a 0.5m height above the sea floor gave a mean abundance of 0.47m−3 in the benthic boundary layer at 4046m and of 2.04m−3 at 3200m. Thirty five minutes after the bait was placed on the sea floor at 3200m, bioluminescent fauna apparently arrived at the bait and produced luminescent displays at a rate of 2min−1. Moving, flashing light sources were observed and luminescent material was released into the bottom current.
The use of inexpensive and high-performance cathode materials is important for constructing large-scale microbial fuel cells (MFCs) for wastewater treatment and bioelectricity production. We show that the air-breathing MFC with a MnO2 (68%)/CNT and polymethylphenyl siloxane (PMPS) coated-stainless steel mesh cathode delivers a maximum power density of 2676mWm−2 (normalized to the cathode surface area) or 86Wm−3 (normalized to the anode chamber volume). The cathode performance is found to be highly replied on the percentage of MnO2 in the as-prepared MnO2/CNT nanocomposites, in which the birnessite-type MnO2 is uniformly formed on the exterior CNT surfaces, as revealed by the scanning electron microscopy (SEM) and X-ray diffraction (XRD) results. Furthermore, it is found that PMPS coated onto the mesh electrode offers the advantages of low cost, easy handling and low water loss and exhibits improved cathode performance as compared to polydimethyl siloxane (PDMS). These findings suggest that the cathode materials, MnO2/CNT and PMPS in MFCs can function well as the electrocatalysts and the water-repellent gas-diffusion layer, respectively.
A series of nickel–cerium hydroxides was prepared via electrodeposition with a designed pH testing system to measure the pH change at the electrode/solution interface in situ. The nickel and cerium contents of these hydroxides were determined by inductively coupled plasma-atomic emission spectrometry. The results indicate that the ratios of Ce/Ni in the obtained nickel–cerium hydroxides have a functional relationship with the pH values of the electrode/solution interface. A thermodynamic study of the Ni–H2O and Ce–H2O systems also confirmed the functional relationship between these systems. Therefore, by adjusting the pH value of the electrode/solution interface using simply designed equipment, the speciation distribution of the two kinds of metal ions in electrodeposition compounds can be controlled approximately.
A layered double hydroxide [Ni4Al(OH)10]OH was doped with different amounts of Zn2+ by coprecipitation and subsequent hydrothermal treatment. The structures of the samples were investigated by XRD, which showed that all are layered double hydroxides with very similar lattice parameters; and samples treated hydrothermally have better crystallinity with ZnO phase. The ZnO exists in rods of several micrometers long, while the [Ni4Al(OH)10]OH in disks of various sizes as shown in SEM images. It has been found that samples treated hydrothermally have higher discharge capacity and better cyclic stability, the maximum discharge capacities are 315mAhg−1 and 300mAhg−1 at discharge current densities of 400mAg−1 and 2000mAg−1, respectively.
By varying the ratio between the amount of carbon and Kynar binder in the cathode of a lithium–oxygen battery, it could be shown that an increasing amount of binder resulted in a decrease in the discharge capacity, mainly as a result of the decrease in the cathode porosity. It was shown that the Kynar binder blocked the majority of the pores with a width below 300Å as determined by studying the pore volume and pore size distribution by nitrogen adsorption. Three carbonate based electrolytes (PC, PC:DEC (1:1), and EC:DEC (2:1) with 1M LiPF6) were tested with the various cathode film compositions. Generally, the PC:DEC and EC:DEC based electrolytes provided higher capacities than PC. The results indicated that the air electrode composition and its effect on the porosity of the cathode, as well as electrolyte properties, are important when optimizing the discharge capacity.
The purpose of this study is to determine the profile of cognitive impairment of ALS using neuropsychological test batteries and ERP measures. We examined 19 sporadic ALS; 8 patients had a spinal, 11 had a bulbar onset of the disease. We compared ALS with normal controls (NCs) that were matched sex, age, and education. Neuropsychological signature was assessed by MMSE and WCST. We also performed correlative studies with respiratory function and clinical acuity (using ALSFRS-R). The auditory “oddball” stimulation was presented and recorded from 20 channels and global field power (GFP) and peak latency of GFP were determined. MMSE score, resulted in more than 24, revealed no obvious dementia of all patients. In ERP study, the prolongation of N1/N2/P3 latency compared with NC was recognized. In correlative study, vital capacity positively correlated with P3 amplitude and negatively with P3 latency. In addition, we found negative correlation between clinical acuity and P3 amplitude, and negative correlation between the acuity of bulbar symptoms and P3 latency. Our findings supported that a reduction of prefrontal function exists in ALS patients, although respiratory failure may also influence cognition indicated by abnormalities of ERP components regardless of ALS subtype.