2D Hydrogenated graphene-like borophene as a high capacity anode material for improved Li/Na ion batteries: A first principles study

Fast-growing electronics industry and future energy storage needs have encouraged the design of rechargeable batteries with higher storage capacities, and longer life times. In this regard, two-dimensional (2D) materials, specifically boron and carbon nanosheets, have garnered enthusiasm due to their fascinating electronic, optical, mechanical and chemical properties. Recently, a hydrogen boride (HB) nanosheet was successfully fabricated showing remarkable stability and superior physical properties. Motivated by this experimental study, we used first principle electronic structure calculations to study the feasibility of this nanosheet to serve as an anode material for Li/Na/Ca/Mg/Al ion batteries. Most active adsorption sites for single adatoms were evaluated and next adatoms were gradually inserted into the anode surface accordingly. The charge transfer, electronic density of sates, storage capacity, structural stability, open-circuit potential and diffusion energy barriers were explored. Our theoretical study predicts that HB shows outstanding electrode properties for Li and Na ion batteries. The intercalation of both Li and Na adatoms into the HB monolayer can lead to a high identical storage capacity of 1133.8 mAh/g which is promising compared to the capacities of the traditional anode materials; such as graphite (372 mAh/g) and TiO2 (200 mAh/g), and other 2D materials; such as germanene (369 mAh/g), stanene (226 mAh/g), and phosphorene (432.8 mAh/g) nanosheets. These results may open a new horizon for the design of rechargeable batteries with higher storage capacitates

A Higher Order Synergistic Damage Model for Prediction of Stiffness Changes due to Ply Cracking in Composite Laminates

A non-linear damage model is developed for the prediction of stiffness degradation in composite laminates due to transverse matrix cracking. The model follows the framework of a recently developed synergistic damage mechanics (SDM) approach which combines the strengths of micro-damage mechanics and continuum damage mechanics (CDM) through the so-called constraint parameters. A common limitation of the current CDM and SDM models has been the tendency to over-predict stiffness changes at high crack densities due to linearity inherent in their stiffness-damage relationships. The present paper extends this SDM approach by including higher order damage terms in the characterization of ply cracking damage inside the material. Following the SDM procedure, predictions are aided by suitable micromechanical computations of crack opening displacements. A nonlinear SDM model is developed and applied for multiple classes of composite laminate layups. Stiffness predictions for damaged laminates using the developed model are compared with the experimental data for cross-ply ([0m/90n]s), angle-ply ([±θm/90n]s), off-axis ([0/±θ4/01/2]s) and quasi-isotropic ([0/90/±45]s) laminates. A comparison with current linear damage models showcases the usefulness of the proposed nonlinear SDM approach

Multiscale modeling of damage in multidirectional composite laminates

The problem of damage accumulation in laminated composite materials hasreceived much attention due to their widespread application in the aerospace, automotive,civil, and sports industries. In the aerospace industry, composites are usedto make light weight and efficient structural components. In the Boeing 787, forexample, more than 50% of the structure is made of composite materials. Althoughthere have been significant developments in analyzing cross-ply laminates, none ofthe present approaches provides reasonable predictions for multidirectional laminatesin which intralaminar cracks may form in multiple orientations. Nevertheless, theprediction of damage accumulation and its effect on structural performance is a verydifficult problem due to complexity of the cracking processes.This study presents a synergistic damage mechanics (SDM) methodology to analyzedamage behavior in multidirectional composite laminates with intralaminarcracks in plies of multiple orientations. SDM combines the strengths of micro-damagemechanics (MDM) and continuum damage mechanics (CDM) in predicting the stiffness degradation due to these cracks. The micromechanics is performed on a representativeunit cell using a three-dimensional finite element analysis to calculate thecrack opening displacement accounting for the influence of the surrounding plies, theso-called constraint effect. This information is then incorporated in the CDM formulationdealing with laminates containing cracks in different ply orientations through a `constraint parameter'. Following CDM, a separate damage mode is defined for eachtype of crack and the expressions for engineering moduli of the damaged laminateare then derived in terms of crack density and the constraint parameter. The SDMmethodology is implemented for [0m/±θn/0m/2]s laminates containing cracks in ±θplies. It is then extended to [0m/±θn/90r]s and [0m/90r/±θn]s laminates with cracksadditionally in the 90°-plies. The predictions agree well with published experimentaldata as well as independent FE computations. Limited parametric studies areperformed to show usability of SDM for more general laminates.To predict the initiation and growth of intralaminar cracks, an energy basedmodel is proposed in which these cracks initiate and multiply when the work requiredto form new set of cracks exceeds a laminate dependent critical energy release rate.The approach requires determination of average crack opening and sliding displacementsat varying crack spacing. This task is performed through a suitable 3-D FEanalysis. In case of off-axis ply cracking, a mixed mode fracture criterion is utilized,where the critical energy release rates in normal and shear modes are determinedby fitting the damage model with the experimental data for a reference laminate.The predictions from the model for [0/± θ4/01/2]s and [0/90/ ± 45]s laminates showremarkable agreement with the experimental results.The methodology and the results covered in this dissertation will be of interest tomechanics of materials researchers as well as to engineers in industry where compositematerials for structural applications are of interest

Comparison of anti-inflammatory efficacy of lercanidipine and Tanacetum parthenium with indomethacin in rats

Background: Inflammation can be classified as either acute or chronic. NSAIDs are the most commonly prescribed drugs worldwide, and mostly have adverse effects. Lercanidipine a CCB of (DHPs) blocks the mediators of inflammation and has additional anti-inflammatory potential. Tanacetum parthenium (Feverfew) extracts have also shown its anti-inflammatory effects in experimental studies. It was decided to study anti-inflammatory effects of Lercanidipine and Tanacetum parthenium which was compared with Indomethacin. The present study was aimed to evaluate and compare the anti-inflammatory effect of lercanidipine and Tanacetum parthenium with Indomethacin in rats.Methods: The study was conducted in the department of Pharmacology UPUMS, Saifai after getting approval from IAEC.A total of 24 animals divided into 4 groups of six (n=6) animals each group were used, and the anti-inflammatory effects of both drugs were evaluated by Carrageenan-induced Paw Edema Model by digital Plethysmometer in rats, drug administration was with the same frequency.Results: The result of the present study had shown that lercanidipine produced anti-inflammatory effect compared to Indomethacin, while its efficacy in reducing paw edema was better at 1st hour, 48 and 72 hours while at 2nd hour and 3rd hour Indomethacin had better efficacy. Tanacetum parthenium also decreased paw edema at 2nd, 3rd, 48 and 72 hour while at 1st hour no effect was seen. However, at 72 hours, shown good efficacy compared to lercanidipine and Indomethacin.Conclusions: Lercanidipine could be a promising anti-inflammatory drug in reducing the inflammation and edema. However, herbal drug (Tanacetum parthenium) has shown anti- inflammatory efficacy when compared with Indomethacin. Both drugs were found safe during our study

Sparse random Fourier features based interatomic potentials for high entropy alloys

Computational modeling of high entropy alloys (HEA) is challenging given the scalability issues of Density functional theory (DFT) and the non-availability of Interatomic potentials (IP) for molecular dynamics simulations (MD). This work presents a computationally efficient IP for modeling complex elemental interactions present in HEAs. The proposed random features-based IP can accurately model melting behaviour along with various process-related defects. The disordering of atoms during the melting process was simulated. Predicted atomic forces are within 0.08 eV/\unicode{xC5} of corresponding DFT forces. MD simulations predictions of mechanical and thermal properties are within 7$\%$ of the DFT values. High-temperature self-diffusion in the alloy system was investigated using the IP. A novel sparse model is also proposed which reduces the computational cost by 94$\%$ without compromising on the force prediction accuracy

A randomized prospective study to compare the efficacy and safety of budesonide plus formoterol and tiotropium plus formoterol in patients having mild to moderate chronic obstructive pulmonary disease

Background: Chronic obstructive pulmonary disease (COPD) is a leading respiratory illness affecting the quality of lives around the world. The present study aims to compare the efficacy and safety of combination of inhaled corticosteroid (ICS) and long acting β2 agonist (LABA) with long acting β2 agonist and long acting muscarinic antagonist (LAMA) in treatment of mild to moderate COPD in a tertiary care hospital.Methods: Total 132 patients with COPD were recruited on the basis of inclusion and exclusion criteria for 8 weeks study from outpatient clinic. A complete pulmonary examination including spirometry examination was done to rule out severe and very severe forms of COPD. Spirometry was performed at the time of recruitment for evaluation of forced expiratory volume in one second (FEV1) and measurement of SpO2 at the time of recruitment at 2 weeks and 8 weeks. Appropriate statistical methods were used to compare the qualitative and quantitative primary and secondary efficacy end points, p value <0.05 was considered significant.Results: On analysis, there was a significant difference (p<0.05) was observed in FEV1 and SpO2 from baseline in ICS plus LABA group (n=66). A similarly significant difference (p<0.05) was observed in LABA and LAMA group (n=66). On comparison between ICS plus LABA and LABA plus LAMA no significant difference in FEV1 and SpO2 was observed between the two groups.  More adverse drug reactions were observed in ICS plus LABA group than LAMA plus LABA group.Conclusions: Combination of ICS and LABA combination is as effective as combination of LABA and LAMA in patients having mild to moderate COPD. However, LABA and LAMA combination is preferable because it is associated with fewer side effects