205 research outputs found
Introduction to supercapacitors, materials and design
No full textSupercapacitors are power devices whose energy storage capability is lower than batteries. These supercapacitors are broadly divided into two types: electric double-layer capacitors and pseudocapacitors. Recently, battery-type electrodes are also used as supercapacitor electrodes to increase energy density. These various categories of supercapacitors are differentiated based on the selection of materials, electrolytes, and their design. Commercial supercapacitors offer various designs such as cylindrical and stacked layers for improving the energy storage capability of supercapacitors. This chapter serves as an introduction to this book, where a glimpse of materials and supercapacitor designs are compiled
Supercapacitors: Materials, Design, and Commercialization
No full textSupercapacitors: Materials, Design, and Commercialization provides a comprehensive overview of the latest research trends and opportunities in supercapacitors, particularly in terms of novel materials and electrolytes. The book addresses the transformation in supercapacitive technology from double layer capacitance to battery-type capacitance, providing a clear understanding of the conceptual differences between various charge storage processes for supercapacitors, charge storage based on materials and electrolytes, and calculation for capacitance for these charge processes. Detailed chapters discuss recent developments in materials, such as carbons, chalcogenides, MXene and phosphorene, various polymer nanocomposites, and polyoxometalates for supercapacitors. This is followed by in-depth coverage of electrolytes, including the evolution of electrolytes from aqueous to water-in-salt electrolytes and their role in improving the energy density of supercapacitors. The final part of the book examines the role of artificial intelligence in the design of supercapacitors, and latest developments in translating novel supercapacitor technologies from laboratory-scale research to a commercialization. © 2024 Elsevier Inc. All rights are reserved including those for text and data mining AI training and similar technologies
Epileptiform activity in the electroencephalogram of 6-year-old children of women with epilepsy
No full textPurpose: To study the epileptiform discharges (EDs) in the electroencephalogram (EEG) of 6-8-year-old children of women with epilepsy (WWE). Materials and Methods: All children born to women with epilepsy and prospectively followed up through the Kerala Registry of Epilepsy and Pregnancy (KREP), aged 6-8 years, were invited (n = 532). Out of the 254 children who responded, clinical evaluations and a 30-min digital 18 channel EEG were completed in 185 children. Results: Of the 185 children examined, 37 (20%) children (19 males, 18 females) had ED in their EEG. The EDs were generalized in 7 children, and focal in 30 children. The EDs were present in the sleep record only of 16 (43%) children and in the awake record only of 6 (16%) children. Out of the 94 children for whom seizure history was available, 7 children (7.4%) had seizures (neonatal seizures: 4, febrile seizure: 1, and single nonfebrile seizure: 2) and none had history of epilepsy or recurrent nonfebrile seizures. The odds ratio (OR) for occurrence of ED in the EEG was significantly higher for children of WWE [OR = 3.5, 95% confidence interval (CI) 2.3-6.0] when compared to the published data for age-matched children of mothers without epilepsy. There was no association between the occurrence of ED and the children′s maternal characteristics [epilepsy syndrome, seizures during pregnancy, maternal intelligence quotient (IQ)] or the children′s characteristics [antenatal exposure to specific antiepileptic drugs (AEDs), birth weight, malformations, IQ]. Conclusion: Children of WWE have a higher risk of epileptiform activity in their EEG when compared to healthy children in the community though none had recurrent seizures
Green's function molecular dynamics meets discrete dislocation plasticity
No full textMetals deform plastically at the asperity level when brought in contact with a counter body even when the nominal contact pressure is small. Modeling the plasticity of solids with rough surfaces is challenging due to the multi-scale nature of surface roughness and the length-scale dependence of plasticity. While discrete-dislocation plasticity (DDP) simulations capture size-dependent plasticity by keeping track of the motion of individual dislocations, only simple two-dimensional surface geometries have so far been studied with DDP. The main computational bottleneck in contact problems modeled by DDP is the calculation of the dislocation image fields. We address this issue by combining two-dimensional DDP with Green's function molecular dynamics. The resulting method allows for an efficient boundary-value-method based treatment of elasticity in the presence of dislocations. We demonstrate that our method captures plasticity quantitatively from single to many dislocations and that it scales more favorably with system size than conventional methods. We also derive the relevant Green's functions for elastic slabs of finite width allowing arbitrary boundary conditions on top and bottom surface to be simulated
Deep eutectic solvents as green and cost-effective supercapacitor electrolytes
No full textDeep eutectic solvents (DESs) have attracted widespread attention as a tempting and capable alternative to traditional electrolytes in energy storage system, particularly in terms of aqueous supercapacitors (SCs). Following the strategy of using eco-friendly and nonflammable electrolyte, low cost, and simple synthesis are other advantages for DESs. They also offer the possibility to construct aqueous all-climate SCs. This chapter comprehensively examines the recent developments and applications of eutectic solvents as electrolytes for SCs. It discusses the unique properties of DESs, their advantages, and challenges, and highlights their potential to enhance the performance and sustainability of SC devices. The chapter also sheds light on the ongoing research efforts and future directions in this rapidly evolving field
Do Nonmotor Symptoms in Parkinson's Disease Differ from Normal Aging?
No full textBackground: Nonmotor symptoms in Parkinson's disease are frequent and affect health-related quality of life of patients. The severity and domains of nonmotor symptoms involved in Parkinson's disease and normal aging have not been compared before.Methods: We performed a prospective case-control study to assess the frequency and severity of nonmotor symptoms in patients with Parkinson's disease (n = 174) and age-matched normal controls (n = 128) using the Non-Motor Symptoms Scale.Results: Nonmotor symptoms in Parkinson's disease were ubiquitous, more frequent, and more severe than in normal aging, particularly in women. Cardiovascular, mood/cognition, and perceptual problems/hallucinations domains were rarely involved in age-matched controls. Age had no effect and sex some influence on nonmotor symptoms in Parkinson's disease. In contrast, in controls, nonmotor symptoms increased with age, and sex had no effect.Conclusions: Nonmotor symptoms in Parkinson's disease differ from those in aging in frequency, severity, sex predilection, and domain involvement. (C) 2011 Movement Disorder Societ
Green's function molecular dynamics: Including finite heights, shear, and body fields
No full textThe Green's function molecular dynamics (GFMD) method for the simulation of incompressible solids under normal loading is extended in several ways: shear is added to the GFMD continuum formulation and Poisson numbers as well as the heights of the deformed body can now be chosen at will. In addition, we give the full stress tensor inside the deformed body. We validate our generalizations by comparing our analytical and GFMD results to calculations based on the finite-element method (FEM) and full molecular dynamics simulations. For the investigated systems we observe a significant speed-up of GFMD compared to FEM. While calculation and proof of concept were conducted in two-dimensions only, the methodology can be extended to the three-dimensional case in a straightforward fashion
Late-onset Boucher-Neuhauser Syndrome (late BNS) associated with white-matter changes: a report of two cases and review of literature
No full textBoucher-Neuhauser syndrome (BNS) is rare autosomal recessive disease, characterised by cerebellar ataxia, hypogonadotropic hypogonadism and chorio-retinal degeneration. The authors report a family (brother, 22 years and sister 24 years) with late-onset BNS (> 10 years). They had subnormal intelligence; the cerebellar ataxia was progressive over 2 years with early functional dependence. Puberty was attained in a brother with testosterone injections, while the girl had primary amenorrhoea. There were no associated visual complaints. They both had diffuse periventricular white-matter hyperintensities in cerebral cortex and diffuse cerebellar atrophy in the MRI
Development of magnesium cobalt oxide and its composite with reduced graphene oxide for asymmetric supercapacitor applications
No full textThis thesis aims to evaluate the suitability of magnesium cobalt oxide (MgCo2O4) as a pseudocapacitor electrode in asymmetric supercapacitors (ASCs) with improved energy density (ED) and power density (PD). MgCo2O4 belongs to ternary metal cobaltites having desirable electrochemical properties for energy storage devices such as batteries
and supercapacitors. In pseudocapacitors, charges are stored at the surface of an electrode by fast faradic reaction and offer improved ED and PD compared to conventional supercapacitors in which charge storage is limited by accumulation at the electrode–
electrolyte interface. In this research, three typical morphologies of MgCo2O4 are synthesized using molten salt method (MSM) and hydrothermal method (HT). These synthetic processes offer controllability of properties of the materials thereby produced and scalability of materials production. A high performing ternary metal cobaltite, viz. manganese cobalt oxide (MnCo2O4) is used as a control material owing to its higher theoretical capacitance (~3620 Fg-1) compared to that of MgCo2O4 (~3120 Fg-1) in all the above synthesis. In addition to the pure compounds, their graphene modified analogues are also synthesized. The materials are characterized using thermogravimetric analysis (TGA), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field
emission scanning electron microscopy (FESEM), and gas surface adsorption techniques. Electrochemical properties of MgCo2O4 and MnCo2O4 are evaluated using cyclic
voltammetry (CV), galvanostatic charge-discharge (CD) and electrochemical impedance spectroscopy (EIS) in a three-electrode system using 3 M LiOH as electrolyte. A detailed investigation of the pseudocapacitive performance of the various electrode including the
graphene modified ones on the specific capacitance (CS) has been undertaken in threeelectrode configuration. These characterizations revealed the superiority of MgCo2O4 over MnCo2O4 electrodes. Furthermore, performance of graphene modified MgCo2O4 and MnCo2O4 showed superior capacitance of ~570 and ~440 Fg-1, with capacitance
retention of 104 and 102%, respectively at the end of 3000 cycles. ASCs are fabricated using graphene modified MgCo2O4 (HS-G-MgCo2O4) and MnCo2O4 (HS-G-MnCo2O4)
as anodes and activated carbon (AC) as cathode. A trial and error method is adopted to determine suitable mass loading of the materials in respective electrodes for high ED and PD. Highest ED and PD are obtained for 1:1 wt.% mass loading in anode and cathode. The HS-G-MgCo2O4/AC delivered a maximum ED of ~31.05 Whkg-1 at PD of 1.8 kWkg-1, which is one of the best performances reported for ternary metal cobaltite based ASCs.
This research, therefore, identifies a promising pseudocapacitor electrode material for commercial deployment
Long-Term Stability of Effects of Subthalamic Stimulation in Parkinson's Disease: Indian Experience
No full textReports of long-term effects of subthalamic (STN) stimulation for Parkinson's disease (PD) are few, mostly open-label evaluations and from Western centers. We used single-blind and open-label motor, cognitive and quality of life (QOL) evaluations to study the effects of bilateral STN stimulation in 45 patients over 5 years. Our patients showed a stable and substantial reduction in the cardinal signs of PD, motor fluctuations, and dyskinesias but less so for axial signs. The reduction in medications and the intensity of electrical stimulation needed also remained stable during follow up. Although the total QOL and its parkinsonism and social components showed sustained benefits till 5 years, the gains in emotional and systemic subsets were short lasting. Global scores for mood and cognition did not show significant worsening. Benefits of STN stimulation on the cardinal signs, motor complications, and QOL of advanced PD were substantial and sustained till 5 years. The initial benefits in axial motor signs and emotional and psychological aspects of QOL did not show similar stability. In general, the procedure had insignificant impact on cognition and mood. This is the first report of STN stimulation in Asian patients with PD. (C) 2010 Movement Disorder Societ
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