batterydata/paper-abstracts huggingface dataset:
In battery packs with cells in parallel, the inter-cell connection resistances can cause unequal loads due to non-uniform interconnect overpotentials and consequentially lead to non-uniform heating. This article explores how load imbalances are generated in automotive applications, by describing a battery pack with finite interconnect resistances. Each cell inside the pack is represented by a pseudo 2D electrochemical model coupled with a lumped thermal model. Increasing the number of cells in parallel results in a linear increase in load non-uniformity, whilst increasing the ratio of interconnect to battery impedance results in a logarithmic increase in load non-uniformity, with cells closest to the load points experiencing the largest currents. Therefore, interconnect resistances of the order of mΩ can have a significant detrimental impact. Under steady state discharge the cell impedance changes until the loads balance. This process, however, can take hundreds of seconds and therefore may never happen under dynamic load cycles. Cycling within a narrow state-of-charge range and pulse loading are shown to be the most detrimental situations. Upon load removal, re-balancing can occur causing further heating. Simulation of a 12P7S pack under a real world load cycle shows that these effects could cause localised thermal runaway.
The aim of the present study was to examine the associations of objectively measured physical activity (PA) with several markers of fatness and fitness in a relatively large sample of adolescents with Down syndrome (DS). This study comprised a total of 100 adolescents with DS (37 females) aged 11–20 years-old, and a sex-matched sample of 100 adolescents without disabilities, participating in the UP&DOWN study. The ALPHA health-related fitness test battery for adolescents was used to assess fatness and fitness. PA was measured by accelerometry. Adolescents with DS had higher fatness and significantly lower fitness levels in all variables measured than adolescents without DS (all p <0.05). Moderate-to-large effects were observed in fatness variables (d =0.65–1.42), but particularly large values were found in fitness variables (d =2.05–2.43). In addition, PA levels was not associated with fatness variables, whereas total PA and vigorous PA were associated with all fitness variables (p <0.05), and moderate-vigorous PA (MVPA) was associated with muscular fitness (p <0.05), after adjusting for potential confounders. Further analysis revealed that there were differences in fitness by tertiles of vigorous PA between the lowest and the highest groups in all fitness variables (all p <0.05). However, no significant differences were found in fitness by tertiles of MVPA according with PA guidelines (≥60min in MVPA). Our findings indicate that PA levels are not associated with fatness variables, whereas high PA levels, in particular vigorous PA, are positively associated with high fitness in adolescents with DS.
Every year, several tens of million tonnes of polymers end up as waste. Contrary to popular belief and optimistic media stories of ever-improving recycling efforts, only a small fraction – indeed, a few percent – of this polymeric litter is actually being recycled and reused. In the U.S., some 3 million tonnes of plastics are recycled annually, yet over 28 million tonnes age unproductively – if the energy of this waste could be harnessed at a moderate 50% efficiency, the greater Chicago area would glow and spark almost all year round! Fortunately, significant progress is being made in technologies that aim at retrieving energy from waste polymers. On the large, often industrial, scales, polymers are being incinerated, pyrolized, and chemically degraded. Some of these technologies can produce viable fuels at costs as low as $0.75 per gallon, some five times smaller than what Mr Smith nowadays pays at the gas pump. There is also plenty of interesting, exploratory science done at smaller scales, where polymers are used in electrostatic or piezoelectric generators, or as materials converting mechanical to chemical energy. Several proof-of-concept devices have been shown to produce enough energy to power personal electronic devices or drive laboratory-scale chemical reactions. Together, the large- and small-scale technologies constitute a realistic strategy to retrieve a sizeable fraction of energy stored in polymers that would otherwise be only presenting a serious environmental concern.
Lithium-ion batteries are commonly employed in various applications owing to high energy density and long service life. Lithium-ion battery models are used for analysing batteries and enabling power control in applications. The Doyle-Fuller-Newman (DFN) model is a popular electrochemistry-based lithium-ion battery model which represents solid-state and electrolyte diffusion dynamics and accurately predicts the current/voltage response using a set of nonlinear partial differential equations. However, implementation of the full DFN model requires significant computation time. This paper proposes a computationally efficient implementation of the full DFN battery model, which is convenient for real-time applications. The proposed implementation is based on applying model order reduction to a spatial and temporal discretisation of the governing model equations. For model order reduction, we apply proper orthogonal decomposition and discrete empirical interpolation method, which leads to a set of reduced order nonlinear algebraic equations. These equations are solved using a particular numerical scheme, based on a damped Newton’s method. In a simulation study, the computational efficiency of the proposed implementation is shown and the resulting accuracy is presented.
Background Children with perinatal arterial ischemic stroke (PAIS) are at risk for later neurocognitive and behavioral deficits, yet the clinical predictors of these outcomes are understudied. We examined the influence of clinical and infarct characteristics on attention and executive functioning in children following PAIS. Methods Forty children born at term (≥37 weeks' gestation) with PAIS (28 with neonatal arterial ischemic stroke and 12 with presumed PAIS) underwent a comprehensive neuropsychological battery at age three to 16 years (median age 7.2 years; 58% male) to assess attention and executive functioning. Parents also completed questionnaires regarding real-world functioning. Clinical variables including perinatal stroke subtype, infarct characteristics (location, laterality, and volume), and the presence of comorbid epilepsy were ascertained from the medical record. Results Presumed PAIS, larger infarct volume, and comorbid epilepsy negatively influenced the performance on attention and executive functioning measures. These clinical variables were also associated with greater functional problems on parent reports, including a higher frequency of attention-deficit/hyperactivity disorder symptoms and greater difficulties in some subdomains of executive functioning. Infarct location and laterality were not associated with performance measures or parental report of functioning. Conclusion Although all children with PAIS are at risk for later deficits in attention and executive functioning, those with presumed PAIS, larger infarct size, and comorbid epilepsy appear to be the most vulnerable. As they approach and reach school age, these children should undergo neuropsychological assessment to ensure timely implementation of therapeutic interventions and behavioral strategies.
A SnO2 anode material undergoes severe capacity loss, which is mainly associated with cracking/crumbling of the material by the large volume change between the Li x Sn and Sn phases, and the intensive reactions with the electrolyte solution. However, AlPO4 nanoparticle coating showed drastically improved electrochemical properties with decreased surface cracks. The AlPO4-coated SnO2 exhibited a capacity of 781mAh/g, approaching its theoretical capacity at the first cycle, with 44% capacity retention after 15 cycles between 2.5 and 0V at a relatively high C rate of 105mA/g. In contrast, the bare SnO2 showed an initial capacity of 680mAh/g, with only 8% capacity retention after 15 cycles.
Laminated lithium-ion polymer cells with gel electrolytes and laminate-film package are expected to replace the conventional alkaline batteries for space application due to their high energy density and high flexibility in configuration. To facilitate this, we assessed the effect of operation conditions, charge rate and taper voltage, on cycle-life testing of commercial lithium-ion polymer cells by simulating a satellite's LEO operation with 40% DOD profile in this work. So far, 6000 cycles have been completed. A lower charge rate was found to be promising for long-term satellite operation. Impedance analysis disclosed a little change in cell internal impedance with charge rate. This encouraged us to attribute the poor cycling performance at high charge rate to excessive lithium-ion exhaust in electrode surface-film formation due to a longer holding duration at taper voltage. The taper voltage was also found to affect charge performance of lithium-ion polymer cells. Good cycling performance, such as the minimum current at the end of the charge and the maximum voltage at the end of the discharge were observed when using taper voltage range from 4.05 to 4.10V. Theoretical analysis deduced that low current at the end of the charge correlated to (1) a low cell internal impedance and (2) a large slope in the capacity–voltage charge curve measured at a low rate. We further evaluated cell cycling behavior at a low rate and indeed observed the largest slope of capacity–voltage charge curve at voltages ranging from 4.05 to 4.10V.
The local structure and oxidation states for both the precursors and the LiFePO4/C composite powders were investigated by X-ray absorption spectroscopy (XAS) to provide a deep insight into their formation mechanism. It was found that the local structure and oxidation states of the precursors and the synthesized LiFePO4/C powders as well as the electrochemical properties of the synthesized powders were strongly influenced by the R ratio (R: molar ratio of citric acid to total metal ions). The oxidation states of iron ions of the precursors for R =1 and 0.75 consist mainly of Fe(II) and traces of Fe(III). However, the oxidation state of iron ions of the precursor for R =0.5 comprises mainly of Fe(III). The oxidation state of iron ions of all the synthesized powders is Fe(II). The structure of the precursors and the synthesized powders for R =1 and 0.75 is more ordering than that for R =0.5. It is in good agreement with the observation of the cation mixing obtained from the Riteveld analysis of the XRD data. The better the electrochemical performance is, the more ordering the structure or the less the cation mixing. However, the effect of the R values on the carbon content is also essential for the electrochemical properties of the synthesized LiFePO4/C composite powders. Increasing the carbon content leads to the increase in the electronic conductivity but impedes the Li+ ion diffusion of the composite materials. Consequently, the powders synthesized at the optimal R ratio of 0.75 exhibited the highest initial capacity, about 150mAhg−1 when cycled at 1/40C rate at room temperature. The structural scheme of the precursors and the synthesized powders and the formation mechanism of the LiFePO4/C composite powders are also addressed in this work.
Background Although a deficit in social cognition is regarded as an early indicator of schizophrenia, few studies have investigated social cognition in ultra-high-risk (UHR) individuals. Methods Our investigation involved subjects at UHR for psychosis (N =33) and an age- and IQ-matched healthy control (HC) group (N =36). Two types of theory of mind (ToM) tasks and a neuropsychological test battery were measured. Results Compared to the HC group, the UHR group performed significantly worse for ToM tasks, with the effect size at an intermediate level (0.64–0.68). Furthermore, the UHR group showed impaired performance in the executive and working memory tests, but not verbal memory tests. These deficits for ToM tests observed in the UHR group were significantly correlated with set-shifting tasks. Conclusions Deficits in social cognition may be modest at the prodromal stage of schizophrenia and may be attributed to prefrontal dysfunction. To prevent or delay transition to psychosis, there is a need for specific preventive strategies targeting social functioning for the UHR group.
Battery packs conformed by large format lithium-ion cells are increasingly being adopted in hybrid and pure electric vehicles in order to use the energy more efficiently and for a better environmental performance. Safety and cycle life are two of the main concerns regarding this technology, which are closely related to the cell's operating behavior and temperature asymmetries in the system. Therefore, the temperature of the cells in battery packs needs to be controlled by thermal management systems (TMSs). In the present paper an improved design methodology for developing TMSs is proposed. This methodology involves the development of different mathematical models for heat generation, transmission, and dissipation and their coupling and integration in the battery pack product design methodology in order to improve the overall safety and performance. The methodology is validated by comparing simulation results with laboratory measurements on a single module of the battery pack designed at IK4-IKERLAN for a traction application. The maximum difference between model predictions and experimental temperature data is 2 °C. The models developed have shown potential for use in battery thermal management studies for EV/HEV applications since they allow for scalability with accuracy and reasonable simulation time.
Abstract Concerns over energy supply security, climate change as well as local air pollution and the increasing prices of energy services are having a growing impact on policy making throughout the world. Today’s energy and transport system, which is based mainly on fossil energy carriers, can in no way be evaluated as sustainable. Increasingly, hydrogen is being promoted as an alternative energy carrier for a sustainable future. For biological H2 systems to become commercially competitive, they must be able to synthesize H2 at rates that are sufficient for practical application. Thermochemical platform provides various efficient methods for conversion of residual biomass (agriculture, forest, and algal) into hydrogen in a single or two stage processes. The processes (gasification, pyrolysis, hydrothermal) and materials/catalysts employed for these processes can be modified to improve the efficiencies for stationary applications/transportation fuel. Integration of various technologies would help in the realisation of hydrogen economy in the future.
Background In patients with refractory heart failure, aortic valve (AV) insufficiency or the presence of a prosthetic AV has been considered a relative contraindication to left ventricular assist device (LVAD) therapy. Nevertheless, we have successfully implanted LVADs in 5 patients with native AV insufficiency or an AV prosthesis by closing the left ventricular outflow tract (LVOT). Methods The method of LVOT closure was tailored to the patients' differing circumstances. Patient 1 had a regurgitant tri-leaflet native AV. Patient 2 had undergone previous aortic root reconstruction with a porcine bioprosthesis. Patient 3 had a congenitally bicuspid AV with significant insufficiency. Patient 4 had a native tri-leaflet valve that developed thrombus and insufficiency after previous LVAD placement. Patient 5 required removal of a recently placed mechanical AV. Accordingly, the LVOT was closed with a bovine pericardial patch in Patients 1, 4 and 5, and the lines of coaptation of the AV leaflets were closed primarily in Patients 2 and 3. Results Four months post-operatively, 1 patient underwent heart transplantation; on removal of the heart, LVOT patch integrity was confirmed visually. After a follow-up period of 6 months to 2 years, the remaining 4 patients are in New York Heart Association Functional Class I while awaiting cardiac transplantation. Transesophageal echocardiography has confirmed persistent LVOT closure. Conclusion In all 5 cases, LVOT closure circumvented the challenges associated with LVAD therapy in the presence of native AV insufficiency or an AV prosthesis.
Lithium ion hybrid electrochemical supercapacitors (Li-HESCs) with higher power density than rechargeable batteries and comparative energy density with supercapacitor have been developed recently to meet the practical applications. A novel Li-HESC is designed in this work with TiNb2O7@carbon negative electrode and carbon fibers positive electrode. TiNb2O7@carbon, a new type lithium ion intercalation pseudo-capacitance electrode, exhibits a capacity of 280mA h/g at a current density of 0.2A/g in the potential window of 1.0–3.0V vs. Li+/Li. Meanwhile, the electrode shows a high specific capacitance of 759F/g when calculated between 1.0 and 2.0V vs. Li+/Li at current density of 0.1A/g. When assembled into a Li-HESC with carbon fiber electrode, an ultrahigh energy density of 110.4Wh/kg is obtained at power density of 99.58W/kg, which also remains at 20W h/kg even under power density of 5464W/kg, much higher than those of the symmetric supercapacitors based on carbon fibers//carbon fibers, CMK-3//CMK-3, and some other Li-HESCs, indicating its potential practical applications in hybrid electric vehicles and electric vehicles.
The novel porous double-shelled SnO2 @ C hollow spheres possess numerous outstanding properties. Its inner active hollow spheres can effectively improve the tag energy density and its double-shelled carbon wrapping outside of each SnO2-shell can protect the integrity of structure as well as enhance electrical conductivity. This is a significant improvement in the design and synthesis of multi-shell or core-shell functional materials. More valuably, the porous hollow structure can not only facilitate liquid electrolyte fast diffusion into the double-shelled spheres but also buffer large volume changes during lithium ions insertion/extraction. Importantly, due to the prominent dispersibility and high specific surface area, the SnO2 spheres can provide sufficient contact areas between active materials and electrolyte so as to improve its electrochemical performance. As a result, the obtained double-shelled SnO2 nanocomposites exhibit excellent rate capability, enhanced cyclability (911mAhg−1 after 100 circles) and high specific energy density. Undoubtedly, the unique structure can provide a reference to effectively utilize hollow structures.
Recent years have shown a large increase in electric vehicles (EVs), which could make a significant contribution meeting European, national and municipal energy- and climate goals. However, most EVs are not used for about 90% of the time, which makes their batteries available for other purposes. One of these purposes could be the provision of Regulating- and Reserve Power (RRP) to the transmission system operator, a vehicle-to-grid (V2G) concept. The aim of this paper is to determine the potential value that EVs could generate by providing RRP and identify EV user impacts on the provision of RRP. A model was developed to simulate the potential value of four commonly sold EVs under a baseline charging- and RRP dispatch scheme with three user categories for one year. The model used minutely settlement prices of the Dutch RRP market from 2014 to 2015, along with charging- and driving characteristics of Dutch EV drivers. Results show substantial effects of RRP provision in terms of monetary benefits, battery throughput and state-of-charge (SOC) distribution. Provision of RRP resulted in monetary benefits in the range between €120 and €750 annually per EV owner, depending on EV- and user category. This is accompanied by increased battery throughput and lower SOC distributions. However, the latter has little effect on the assumed trip requirements of the EV user. Subsequently, an assessment was made on the sensitivity of the results for changes in user characteristics and fleet sizes, which offered both favourable prospects and limitations. We conclude that the provision of RRP by EVs in the Netherlands shows promising potential.
Lithium ion capacitors (LICs), which bridge the gap between lithium ion battery and electric double layer capacitor, have recently attracted considerable attention. Herein, we first propose the possible utilization of nitrogen-doped carbonized polyimide microsphere (CPIMS) as a novel anode material of LICs. The structures and lithium intercalation properties of CPIMS treated at different temperatures are investigated. It is demonstrated that some of nitrogen atoms are kept in the CPIMS, which is helpful for improving the electrochemical performances. The CPIMS900 (900 is the carbonization temperature) can deliver specific capacities of 328.3 and 48.2mAhg−1 at 10mAg−1 and 10Ag−1, respectively. When the pre-lithiated CPIMS900 is coupled with an activated carbon cathode, an energy density of 28.5Whkg−1 at 348Wkg−1 is obtained based on the weight of both electrode materials. Even at 6940Wkg−1, the energy density still remains 13.1Whkg−1. After 5000 cycles at 500mAg−1, the capacity retention ratio is as high as 97.1%. The present work offers an opportunity to utilize the CPIMS material in LIC with high energy density, high power density and promising cycle life.
Numerous studies showed that adults with attention deficit hyperactivity disorder (ADHD) suffer from impairments in a range of cognitive functions when compared to healthy controls. However, only little is known about the neuropsychological functions when compared to various clinical control groups and whether a distinct neuropsychological profile can be identified for adult ADHD.
The commercialization of lithium–sulfur batteries is hindered by serious capacity fading that mainly results from the irreversible oxidation of sulfur active material during cycling, but so far the underlying oxidation mechanism still remains unclear. The research results reveal that the most practical solvent DOL and DME are not stable and large amount of degradation products with -OLi edge groups become the oxygen source. The shuttle phenomenon is an important reason leading to the irreversible oxidation of sulfur active material, which results from series chemical reductions of lithium polysulfide, and they keep charge conservation by their selves, but prolong the charge process and lead to the overcharging. In charge process, the low speed reactions of long-chain lithium polysulfide oxidized to Li x SO y species exist in the electrolyte, which are indistinctly in the systems without overcharging. As the shuttle phenomenon prolongs the charge process, the irreversible oxidation reactions become distinctly, and the Li x SO y species are detectable. The overcharging capacity could be explained as a reversible part and an irreversible part. The reversible capacity is from the cathode active material oxidized to long-chain lithium polysulfide and elemental sulfur, and the irreversible capacity is from the long-chain lithium polysulfide oxidized to Li x SO y species.
This study shows for the first time that poly(p-phenylene) (PPP) nanowires can be easily obtained by electrochemical synthesis at room temperature. The method involves the template assisted electropolymerization of benzene in the air and water stable ionic liquid 1-hexyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate ([HMIm]FAP). Track-etched polycarbonate membranes (PC) with an average pore diameter of 90nm were used as templates. Dense and highly flexible bundles of PPP nanowires with a high aspect ratio (>160) were easily obtained by this method. In addition, we present here our first results to obtain PPP/TiO2 nanowires by the combination of a sol–gel technique with electropolymerization. HR-SEM, TEM and EDX were used for the structural characterization of the nanowires.