batterydata/paper-abstracts huggingface dataset:
The development of electric vehicles (EVs) demands for complementary technologies in battery thermal management. To achieve fast charging/discharging capacity, liquid cooling is an effective means of maintaining temperature of a battery in operation within a narrow optimal range. In conventional straight channels, convective heat transfer deteriorates along the axial direction with the development of the hydrodynamic boundary layer, resulting in elevated maximum temperature and significant temperature gradient in the fully developed region. This is a serious problem as temperature uniformity is of utmost importance to the performance and lifespan of a Li–ion battery. In this research, a simple configuration of oblique cuts across the straight fins of a conventional straight channel design was developed, to enhance the performance of the conventional channel with minimal pressure penalty. These oblique cuts across the straight fins form an oblique fin array. The designed liquid cold plate (LCP) contains these simple oblique fins with optimized angle and width. This segmentation of the continuous fin into oblique sections leads to the re-initialization of boundary layers, providing a solution to the elevated temperatures caused by a thick boundary layer in the fully developed region. Experimental results show that heat transfer coefficients of oblique minichannel are higher than those of conventional straight minichannel. The oblique LCP is able to maintain the battery surface average temperature below 50°C for a heat load of 1240W at a flow rate lower than 0.9l/min. This implies that a proper designed minichannel cold plate could be a promising solution for EV battery thermal management.
This paper proposes a simple and easily optimizable mathematical representation of an energy management strategy (EMS) for the hybrid energy storage system (HESS) in EV. The power of each device in the HESS is provided as a continuous function of load power called γ. Two strategies based on the proposed method, one incorporating fixed coefficients of the γ function (GBS) and one with coefficients optimized by a genetic algorithm (GAS) in real-time using a backward time window, are tested and compared to the rule-based strategy (RBS) and battery storage system. The calculations are made for an electric car with a LiFePO4 battery-supercapacitor HESS. The analyzed parameters are: energy consumption, RMS and maximum current rates of the battery, and the cycle cost of an EV with HESS and a battery-powered EV. The analysis is made in dependence on drive cycle speed and an internal resistance of the battery module. The obtained results show that the GBS and the GAS are able to reduce the RMS current rate by 40% in the NEDC in comparison to battery-powered EV, as well as that maximum current rates do not exceed nominal values. The GAS aims at the minimization of energy consumption. It obtains best results in low speed cycles.
CYFIP1, a protein that interacts with FMRP and regulates protein synthesis and actin dynamics, is overexpressed in Dup15q syndrome as well as autism spectrum disorder (ASD). While CYFIP1 heterozygosity has been rigorously studied due to its loss in 15q11.2 deletion, Prader-Willi and Angelman syndrome, the effects of CYFIP1 overexpression, as is observed in patients with CYFIP1 duplication, are less well understood.
The effect of the preparation and treatment conditions on the photoefficiency of electropolymerized polybithiophene (PBT) was studied. It was found that, after initial discharging, further electrochemical undoping of the polymer in dark had no effect on the photocurrents. However, illuminating the polymer films in solutions containing Li+ ions resulted in a five-fold increase in the photocurrent. This fact was attributed to photoelectrochemical removal of the trapped charge that was present in the as-grown polymer films. This conclusion was confirmed by local conductivity measurements using current-sensing atomic force microscopy (CS-AFM). The as-grown polymer films showed a high degree of microscopic heterogeneity and well-pronounced conducting domains of submicrometer dimensions embedded into a nominally undoped polymer phase. Further, electrochemical undoping in dark failed to produce any noticeable change in the trapped charge content. The photoelectrochemical treatment, however, drastically improved the microscopic homogeneity of the polymer and its semiconductor properties, as indicated by CS-AFM images and current-voltage characteristics. The maximum steady-state photocurrent obtained in LiPF6 was 1.4mAcm−2 under 20mW 405nm monochromatic laser illumination, which corresponded to an external quantum efficiency of 1.5%. This result indicates that, upon necessary optimization, single-layer polymer photoelectrodes can produce relatively high photocurrents without employing the donor–acceptor architectures.
Detection of triatomine bugs within a house is essential for the estimation of Chagas disease transmission risk and for evaluating the success of insecticidal control attempts. Small residual populations could represent an important risk but are difficult to detect by time manual sampling. Faecal marks from triatomines are clearly detectable with an ultraviolet (UV) light on most of the materials frequently used in rural buildings. A new method for finding triatomines is proposed here, based on the unexplored property of faeces to fluoresce when exposed to UV light.
A new ac impedance spectroscopy method is proposed to follow the charge–discharge processes of nickel oxo-hydroxide electrode (NOHE) in KOH media and thereafter to determine their state of charge (SOC), involving in situ measurements of the impedance between two electronic contacts soldered on opposite edges of the electrode. A transmission line (TL) model is developed and fitted to experimental results. The physical significance of its parameters is discussed, taking into account one- and two-phase domains.
Allied health assistants (AHAs) are support staff who complete clinical and non-clinical tasks under the supervision and delegation of an allied health professional. The effect of allied health professional delegation of clinical tasks to AHAs on patient and healthcare organisational outcomes is unknown. The purpose of this systematic review was to investigate the effect of allied health professional delegation of therapy to AHAs on patient and organisational outcomes.
Objective The present investigation was designed to explore the role and implications of both daytime sleepiness and fatigue in obstructive sleep apnea syndrome with respect to sleep, perceived health quality, and psychological functioning. Methods Our participants consisted of two groups: 124 older community volunteers who completed a polysomnographic sleep study and were diagnosed with sleep apnea, and 19 healthy controls. All participants completed self-report measures of sleepiness, fatigue, sleep quality, health quality, and psychological functioning. Results The apnea sample was divided according to clinically relevant cut-offs on sleepiness and fatigue. When those with mid-range scores were ruled out, the following groups remained: low sleepiness/low fatigue (LL, n=23), high sleepiness/high fatigue (HH, n=28), high sleepiness/low fatigue (HS, n=10) and low sleepiness/high fatigue (HF, n=13). The respiratory disturbance index did not differ significantly among these groups and only the two highly fatigued groups (HH and HF) experienced significantly lower average oxygen saturation than the control group. Analyses revealed that the HH group was significantly worse than the LL and control groups on most sleep, health quality, and psychological measures. On these same measures, the groups for whom fatigue was low (LL and HS), regardless of sleepiness, were similar to controls. Conclusion When patients with sleep apnea are classified into different sleepiness/fatigue categories, the results show that high fatigue is associated with more severe dysfunction than high sleepiness. The current debate on whether to treat apnea patients with low sleepiness needs to consider the impact of fatigue.
This paper presents a computational modeling approach to characterize the internal temperature distribution within a Li-Ion battery pack. In the mathematical formulation both entropy-based and irreversible-based heat generation have been considered; combined with CFD software in order to simulate the temperature distribution and evolution in a battery pack. A prismatic Li-ion phosphate battery is tested under constant current discharge/charge rates of 1C, 2C, 5C and 8C. Model parameters (in particular, the entropic heat coefficient and the internal resistance) needed for the calibration of the model are determined using experimentation. The model is then used to simulate two different strategies for the thermal control of a battery pack in case of car application: an air-cooling and a liquid-cooling strategy. The simulation has highlighted the pros and cons of the two strategies, allowing a good understanding of the needs during the process of battery pack design and production.
Free-standing gel polymer electrolytes with poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) matrix plasticized with tetraethylene glycol dimethyl ether (TEGDME) were prepared and investigated. The as-prepared gel polymer electrolytes exhibited large operating window and acceptable ionic conductivity. When applied in lithium oxygen batteries, the gel polymer electrolyte could support a high initial discharge capacity of 2988mAhg−1 when a carbon black electrode without catalyst was used as cathode. Furthermore, the battery with gel polymer electrolyte can last at least 50 cycles in the fixed capacity cycling, displaying an excellent stability. Detailed study reveals that the gelling process is essential for the cycling stability enhancement. With excellent electrochemical properties, the free-standing gel polymer electrolyte presented in this investigation has great application potentials in long-life lithium oxygen batteries.
Background Vision affects daily activities, but of particular importance is the impact upon the learning process. Many studies have been conducted to establish the relationship between vision problems and academic performance. The results are varied, however, and suggest additional research is needed with particular care given to study design. Methods This study included 1,103 year-2 school children enrolled in 7 public schools in the Klang Valley region of Malaysia. There were an equal proportion of males (50.6%) and females (49.4%). The testing battery was designed to assess visual acuity, ocular muscle balance, visual analysis skills, visual-spatial skills, and visual-motor integration skills. Results Children with average and above-average achievement showed a different visual performance profile from those children with low academic achievement. They had a statistically significant better pass rate in physical aspects (visual acuity), physiological aspects (ocular motor balance), and perceptual aspects (visual-motor integration/visual-spatial and visual-analysis skills). Conclusion Children with low academic achievement are more likely to exhibit problems in visual acuity, ocular motor balance, visual-motor integration and most all components of visual analysis skills. This finding supports the concept that visual performance is key to learning and therefore of chief concern as to school achievement.
Lithium-ion cells show a reversible capacity fade at low C-rates (C/10) at temperatures below T =0°C. This phenomenon cannot solely been explained by temperature induced impedance raise and the formation of solid electrolyte interphases any more. We investigate four different cell chemistries at temperatures T =25, 0, −10 and −20°C. All measurements are carried out on full cells. The activation energies and especially the ratio of anodic and cathodic activation energies have the highest impact on capacity fading at low C-rates. For quantification of the ratio, we define an activation factor between anodic and the cathodic activation energies. We derive temperature and activation energy behavior on basis of the Butler–Volmer equation for increasing internal voltages and polarization. High activation energies causes high energy demand for activation polarization and an earlier reach of cut-off voltages. If the negative and positive electrode are well balanced with respect to activation energies, the internal voltages which are induced at electrodes boundary layers (electrochemical double layer) are small and the pseudo open circuit voltages lower.
Rational design and construction of advanced hybrid electrodes would contribute to enormous development of rechargeable batteries. Herein, hierarchical accordion-like TiO2/Ti3C2 nanohybrid is purposefully synthesized by using Ti3C2 as single precursor through a scalable hydration process, and further evaluated as promising anode material both for Li-ion batteries (LIBs) and Na-ion batteries (SIBs). Physicochemical characterizations demonstrate that the unique hierarchical nanohybrid possesses a layered architecture, where the in-situ formed nanoscaled TiO2 is decorated uniformly on the Ti3C2 surface. Benefiting from synergetic contributions from interlayer-expanded architecture, high-capacity nano-TiO2 and excellent electrical conductivity of the Ti3C2, the resulted TiO2/Ti3C2 anode exhibits large reversible capacities of ∼267 and ∼101 mAh g−1 for LIBs and SIBs, respectively, at a current density of 200 mA g−1. Moreover, no any capacity decay over consecutive 500, and even 2000 cycles at high rates further confirms its outstanding electrochemcial stability for practical applications. More appealingly, all the results highlight that the cost-efficiency TiO2/Ti3C2 hybrid architecture would be a promising anode candidate for advanced next-generation LIBs and SIBs.
Nanostructured NiO plates on 3-dimensional porous nickel foam were prepared by hydrothermally treating the commercial nickel foam in an alkaline (NH4)2S2O8 solution followed by annealing in the air. The microstructures and electrochemical performance as well as electrochemically induced phase evolution of the nanostructured NiO electrodes were investigated. Working with a Li metal counter electrode, the hierarchically nanostructured NiO electrode presents a high reversible specific capacity of 604mAh g−1 at 1.25C even after 100 cycles and excellent rate performance with a specific capacity of 320mAhg−1 at 8C. TEM investigations conducted at several representative charge/discharge statuses reveal that an intermediate phase of Li2NiO2 produced during the redox conversion between metallic Ni and NiO. Therefore, the reactions of NiO electrode for Li-ion storage can be described as NiO↔0.5Ni+0.5Li2NiO2 ↔Ni+Li2O.
In order to improve the energy density and battery efficiency of vanadium redox flow battery based on sulfate-chloride mixed acid electrolyte, the viscosity, conductivity and electrochemical performance of electrolytes with different concentration compositions are investigated systematically. The viscosity of electrolytes with four valences both increase with vanadium concentration, sulfate concentration and chloride ion concentration, the conductivity increase with sulfate concentration and chloride ion concentration but decrease with vanadium concentration. The results of electrochemical measurements indicate that the electrolyte with 2.2 M vanadium concentration, 2.75 M sulfate concentration and 5.8 M chloride ion concentration presents the best electrochemical performance due to common effect of the viscosity, conductivity and active vanadium ion concentration. The battery performance of electrolytes show that the ohmic polarization, concentration polarization and electrochemical polarization of electrolytes have great influences on the charging and discharging voltage platform which leads to the change of battery efficiency. In consideration of the improvement of battery efficiency and capacity, the electrolyte containing 2.2 M vanadium concentration, 2.75 M sulfate concentration and 5.8 M chloride ion concentration is selected as the optimum combination which can provide theoretical direction for the engineering application of vanadium redox flow battery based on sulfate-chloride mixed acid electrolyte.
Solid ionic conductors with good conductivity at room temperature and mechanical flexibility are very attractive candidates for application as electrolytes for secondary lithium batteries. Plastic crystal electrolytes formed by doping succinonitrile with lithium salts can potentially meet these requirements. In this study, succinonitrile doped with various lithium salts were characterized by differential scanning calorimetry, powder X-ray diffraction, conductivity measurements and in electrochemical studies. The much better conductivities and electrochemical performance of certain lithium salts in comparison to the others studied has been found to be correlated to their propensity to form crystalline adducts with succinonitrile at low molar concentrations. Of the lithium salts studied, only two which did not form crystalline adducts at low concentrations: lithium bis-trifluoromethanesulphonylimide (Li[CF3SO2]2N) and lithium tetrafluorborate (LiBF4) had high enough conductivities at ambient temperature for evaluation in lithium cells. Contrary to prior predictions, both showed reasonable capacities, high coulombic efficiencies, and good capacity retention even with metallic lithium as the anode.
Increasing the specific energy of a lithium ion battery and maintaining its cycle life is a predominant goal and major challenge for electrochemical energy storage applications. Focusing on the positive electrode as the specific energy bottleneck, cycle life characteristics of promising layered oxide type active materials (LiMO2) has been thoroughly investigated. Comparing the variety of LiMO2 compositions, it could be shown that the “Ni-rich” (Ni ≥ 60% for M in LiMO2) electrodes expectably revealed best performance compromises between specific energy and cycle life at 20 °C, but only LiNi0.6Mn0.2Co0.2O2 (NMC622) could also maintain sufficient cycle performance at elevated temperatures. Focusing on NMC622, it could be demonstrated that the applied electrochemical conditions (charge capacity, delithiation amount) in the formation cycles significantly influence the subsequent cycling performance. Moreover, the insignificant transition metal dissolution, demonstrated by means of total X-ray fluorescence (TXRF) technique, and unchanged lithiation degree in the discharged state, determined by the measurement of the Li+ content by means of the inductively coupled plasma optical emission spectroscopy (ICP-OES) technique, pointed to a delithiation (charge) hindrance capacity fade mechanism. Considering these insights, thoughtful modifications of the electrochemical charge conditions could significantly prolong the cycle life.
Although Li metal has been regarded as one of the most promising anode materials, an unstable Li/electrolyte interface during the cycling process seriously limits its practical application in rechargeable batteries. Herein, we report a transplantable LiF-rich layer (TLL) that can suppress the side reactions between electrolyte and lithium metal. This peelable layer cross-linked by nanoscale LiF domains is obtained by electrochemically reducing NiF2 electrodes and could be used to protect Li metal anodes. Cu-Li cells using the TLL protection can operate for more than 300 cycles with a Coulombic efficiency as high as ~ 98% in carbonate-based electrolytes. In Li-LiFePO4 cells, lithium metal with a TLL still looks shiny after 1000 cycles (~ 6 months) in contrast to the black surface of bare lithium foil after ~ 500 cycles (~ 3 months). These results clearly demonstrate that the TLL could greatly limit the side reactions between lithium metal and the carbonate-based electrolytes, and may enable long-term stable operation of Li metal batteries.
The impact of using a Novel Tobacco Vapor (NTV) product on indoor air quality (IAQ) was simulated using an environmentally-controlled chamber. Three environmental simulations were examined; two non-smoking areas (conference room and dining room) and one ventilated smoking area (smoking lounge). IAQ was evaluated by (i) measuring constituents in the mainstream NTV product emissions, (ii) and by determining classical environmental tobacco smoke (ETS) and representative air quality markers. Analysis of the mainstream emissions revealed that vapor from the NTV product is chemically simpler than cigarette smoke. ETS markers (RSP, UVPM, FPM, solanesol, nicotine, 3-ethenylpyridine), volatile organic compound (toluene), carbon monoxide, propylene glycol, glycerol, and triacetin were below the limit of detection or the limit of quantification in both the non-smoking and smoking environments after using the NTV product. The concentrations of ammonia, carbonyls (formaldehyde, acetaldehyde, and acetone), and total volatile organic compounds were the same levels found in the chamber without NTV use. There was no significant increase in the levels of formaldehyde, acetone or ammonia in exhaled breath following NTV use. In summary, under the simulations tested, the NTV product had no measurable effect on the IAQ, in either non-smoking or smoking areas.
The article is intended to familiarize test-users with the issues they need to consider when employing assessments for screening/admission purposes. The article examines the purpose, content, and scoring methods of three English as a second language admission tests — the Cambridge certificate exams, International English Language Testing System, and Test of English as a foreign language-computer-based test — and discusses reliability and validity considerations salient to each instrument. The validity and reliability discussion is guided by the “Standards for Educational and Psychological Testing” (1999). The article indicates that the scores obtained from these assessments are used to help make critical decisions that affect test-takers’ lives. It is critical, therefore, that these scores provide high quality information. Developers of large-scale tests such as those reviewed in the present article have the responsibility to: construct instruments that meet professional standards; continue to investigate the properties of their instruments and the ensuing scores; and make test manuals, user guides and research documents available to the public. Test-users also have a responsibility. Test-users need to be cognizant of the properties of the instruments they employ and ensure appropriate interpretation and use of test scores provided. Test-users need to carry out local investigations to make sure that their admission requirements are based on an informed analysis of their academic programs and the language ability score profiles necessary to succeed in these programs.
It is a great challenge to combine good cycling performance with high rate capability for LiMn1–xMxPO4 cathode materials owing to the Mn dissolution upon cycling and its low electronic/ionic conductivity. Here, we report a novel concentration-gradient structure of LiMn0.8Fe0.2PO4 material constructed by solvothermal treatment. This material shows a linear increase of Mn concentration from the edge to the particle centre, but the inverse trend for Fe concentration, which leads to the formation of Mn-rich phase in bulk and Fe-rich phase at surface. The Fe-rich phase effectively suppresses the corrosion from the electrolyte that minimizes the Mn dissolution and also improves the electronic/ionic conductivity of the surface that decreases the cathode/electrolyte interface resistance. Consequently, this concentration-gradient material achieves superior capacity retention with 98% after 50 cycles at 1 °C even at elevated temperature, and also exhibits an excellent rate capability with the reversible capacity of 130 mA h g−1 at 5 °C rate. These results suggest that the concentration-gradient LiMn0.8Fe0.2PO4 is an ideal type of cathode material for high performance Lithium ion batteries.