Secondary-Phase-Induced Charge–Discharge Performance Enhancement of Co-Free High Entropy Spinel Oxide Electrodes for Li-Ion Batteries

High entropy oxide (HEO) has emerged as a new class of anode material for Li-ion batteries (LIBs) by offering infinite possibilities to tailor the charge–discharge properties. While the advantages of single-phase HEO anodes are realized, the effects of a secondary phase are overlooked. In this study, two kinds of Co-free HEOs are prepared, containing Cr, Mn, Fe, Ni, and Zn, for use as LIB anodes. One is a plain cubic-structure high entropy spinel oxide HESO (C) prepared using a solvothermal method. The other HESO (C+T) contains an extra secondary phase of tetragonal spinel oxide and is prepared using a hydrothermal method. It is demonstrated that the secondary tetragonal spinel phase introduces phase boundaries and defects/oxygen vacancies within HESO (C+T), which improve the redox kinetics and reversibility during electrode lithiation/delithiation. Density functional theory calculation is performed to assess the phase stability of cubic spinel, tetragonal spinel, and rock-salt structures, and validate the cycling stability of the electrodes upon charging–discharging. The secondary-phase-induced rate capability and cyclability enhancement of HEO electrodes are for the first time demonstrated. A HESO (C+T)||LiNi_0.8Co_0.1Mn_0.1O₂ full cell is assembled and evaluated, showing a promising gravimetric energy density of ≈610 Wh kg⁻¹ based on electrode-active materials.     

Singular Perturbation Method for Smart Building Temperature Control Using Occupant Feedback

In this work we propose a framework for incorporating occupant feedback towards temperature control of multi‐occupant spaces, and analyze it using singular perturbation theory. Such a system would typically have to accommodate occupants with different temperature preferences, and incorporate that with thermal correlation among multiple zones to obtain optimal control for minimization of occupant discomfort and energy cost. In current practice, an acceptable temperature set point for the occupancy level of the zone is estimated, and the control law is designed to maintain temperature at the corresponding set point irrespective of the changes in occupancy and the preferences of multiple occupants. Proposed algorithm incorporates active occupant feedback to minimize aggregate user discomfort and total energy cost. Occupant binary feedback in the form of hot/cold or thermal comfort preference input is used by the control algorithm. The control algorithm also takes the energy cost into account, trading it off optimally with the aggregate occupant discomfort. For convergence to the optimal, sufficient separation between the occupant feedback frequency and the temperature dynamics of system is necessary; in absence of which, the occupant feedback provided do not correctly reflect the effect of current control input value on occupant discomfort. Under sufficient time scale separation, using singular perturbation theory, we establish the stability condition of the system and show convergence of the proposed solution to the desired temperature that minimizes energy cost plus occupant discomfort. The occupants are only assumed to be rational in that they choose their own comfort range to minimize individual thermal discomfort. Optimization for a multi‐zone building also takes into account the thermal correlation among different zones. Simulation study with parameters based on our test facility, and experimental study conducted in the same building demonstrates performance of the algorithm under different occupancy and ambient conditions.     

A voting-based technique for word spotting in handwritten document images

Multimedia Tools and Applications - Word spotting in handwritten document images is a field of immense interest due to its widespread applications. Recognition-free and recognition-based approaches...     

Designing balanced wrapper chains in 3D SoC under constrained TSVs

Innovations in Systems and Software Engineering - Three-dimensional integrated circuit (3D-IC) has emerged as a savior of failing Moore’s law, where reduced length of interconnects is...     

Can deep learning solve a preschool image understanding problem?

Neural Computing and Applications - Automatic assessment of learning is a process where the computer system automatically generates test items and evaluates the responses. Image is one of the major...     

FDRF: Fault Detection and Recovery Framework for Seamless Data Transmission in Remote Health Monitoring Using WBAN

Wireless Personal Communications - Health monitoring systems based on Sensors, IoT and Cloud server have gained popularity in recent time. In this work patient either wear small sensors or they are...     

Treatment of arsenic contaminated water in a laboratory scale up-flow bio-column reactor

The present paper describes the observations on the treatment of arsenic contaminated synthetic industrial effluent in a bio-column reactor. Ralstonia eutropha MTCC 2487 has been immobilized on the granular activated carbon (GAC) bed in the column reactor. The synthetic water sample containing As(T) (As(III):As(V)=1:1), Fe, Mn, Cu and Zn at the initial concentrations of 25, 10, 2, 5, 10 ppm, respectively, was used. Concentrations of all the elements have been found to be reduced below their permissible limits in the treated water. The significant effect of empty bed contact time (EBCT) and bed height on the arsenic removal was observed in the initial stage. However, after some time of operation (approximately 3-4 days) no such effect was observed. Removal of As(III) and As(V) was almost similar after approximately 2 days of operation. However, at the initial stage As(V) removal was slightly more than that of As(III). In absence of washing, after approximately 4-5 days of operation, the bio-column reactor was observed to act as a GAC column reactor based on physico-chemical adsorption. Like arsenic, the percent removals of Fe, Mn, Cu and Zn also attained minimum after approximately 1 day and increased significantly to the optimum value within 3-4 days of operation. Dissolved oxygen (DO) has been found to decrease along with the increasing bed height from the bottom. The pH of the solution in the reactor has increased slightly and oxidation-reduction potential (ORP) has decreased with the time of operation.     

Highly efficient electroosmotic flow through functionalized carbon nanotube membranes

Carbon nanotube membranes with inner diameter ranging from 1.5-7 nm were examined for enhanced electroosmotic flow. After functionalization via electrochemical diazonium grafting and carbodiimide coupling reaction, it was found that neutral caffeine molecules can be efficiently pumped via electroosmosis. An electroosmotic velocity as high as 0.16 cm s(-1) V(-1) has been observed. Power efficiencies were 25-110 fold improved compared to related nanoporous materials, which has important applications in chemical separations and compact medical devices. Nearly ideal electroosmotic flow was seen in the case where the mobile cation diameter nearly matched the inner diameter of the single-walled carbon nanotube resulting in a condition of using one ion is to pump one neutral molecule at equivalent concentrations.     

A study on thermal properties of single-jersey knitted fabrics produced from ring and compact folded yarns

This paper presents a study on the thermal properties of single-jersey knitted fabrics manufactured using ring, compact and ring/compact folded yarns. The variations in thermal properties depending on the yarn twist and traveller weight of folded yarn single-jersey knits were discussed. It was found that the thermal resistance of knitted fabrics generally increases as the traveller weight decreases, and also water vapour permeability reduces as the traveller weight decreases. The water vapour permeability and air permeability of knitted fabrics increase as the twist increases. The thermal conductivity of knitted fabrics decreases as the twist increases. The air permeability and water vapour permeability values were higher for compact folded yarn fabrics as compared to those values of ring and ring/compact folded yarn fabrics. It is observed that yarn twist and traveller weight have affected different thermal properties of single-jersey folded yarn fabrics.     

Performance of line codes in optical direct detection continuous phase frequency shift keying transmission system impaired by polarization mode dispersion

Small deviations from perfect circular symmetry in the core region of single mode fiber (SMF) cause optical pulses to become broadened as they propagate. This phenomenon is referred to as polarization mode dispersion (PMD), which leads to intersymbol interference and becomes a major impediment for the high speed long-haul fiber-optic links. We present here the theoretical complement for evaluating the performance of a line-coded continuous phase frequency shift keying (CPFSK) optical transmission system with a direct detection receiver. The analysis is carried out for two different line-coding schemes, i.e. alternate mark inversion (AMI) and order-1 coding, to investigate the effectiveness of the line coding in counteracting the effect of PMD in a CPFSK direct detection transmission system in the presence of group velocity dispersion (GVD) and receiver noise in a single mode fiber. The average bit error rate (BER) performances are evaluated without and compared to that of line codes at a bit rate of 10 Gb s^?1 considering Maxwellian distribution for the mean differential group delay (DGD). We found that the amount of power penalty improvement of line-coded systems is within 0.65 to 2.25 dB with respect to NRZ data at a BER of 10^?9.