APPROXIMATIONS OF SOLUTIONS FOR A NONLOCAL FRACTIONAL INTEGRO-DIFFERENTIAL EQUATION WITH DEVIATED ARGUMENT

CHADHA, ALKA,PANDEY, DWIJENDRA N. The Korean Society for Computational and Applied M 2015 Journal of applied mathematics & informatics Vol.33 No.5

This paper investigates the existence of mild solution for a fractional integro-differential equations with a deviating argument and nonlocal initial condition in an arbitrary separable Hilbert space H via technique of approximations. We obtain an associated integral equation and then consider a sequence of approximate integral equations obtained by the projection of considered associated nonlocal fractional integral equation onto finite dimensional space. The existence and uniqueness of solutions to each approximate integral equation is obtained by virtue of the analytic semigroup theory via Banach fixed point theorem. Next we demonstrate the convergence of the solutions of the approximate integral equations to the solution of the associated integral equation. We consider the Faedo-Galerkin approximation of the solution and demonstrate some convergenceresults. An example is also given to illustrate the abstract theory.

A new insight into the structural modulation of graphene oxide upon chemical reduction probed by Raman spectroscopy and X-ray diffraction

Chadha Neakanshika,Sharma Rahul,Saini Parveen 한국탄소학회 2021 Carbon Letters Vol.31 No.6

Lately, Raman spectroscopy has become powerful tool for quality assessment of graphene analogues with identifcation of intensity ratio of Raman active D-band and G-band (ID/IG ratio) as a vital parameter for quantifcation of defects. However, during chemical reduction of graphitic oxide (GrO) to reduced GrO (RGrO), the increased ID/IG ratio is often wrongly recognized as defect augmentation, with “formation of more numerous yet smaller size sp2 domains” as its explanation. Herein, by giving due attention to normalized peak height, full-width half-maxima and integrated peak area of Raman D- and G-bands, and compliment the fndings by XRD data, we have shown that in-plane size of sp2 domains actually increases upon chemical reduction. Particularly, contrary to increased ID/IG ratio, the calculated decrease in integrated peak area ratio (AD/AG ratio) in conjunction with narrowing of D-band and broadening of G-band, evinced the decrease in in-plane defects. Finally, as duly supported by reduction induced broadening of interlayer-spacing characteristic XRD peak and narrowing of~43° centered XRD hump, we have also shown that the sp2 domains actually expands in size and the observed increase in ID/IG ratio is indeed due to increase in across-plane defects, formed via along-the-layer slicing of graphitic domains.

On the Role of Chromium in Dynamic Transformation of Austenite

K. Chadha,Davood Shahriari,C. Jr. Aranas,Louis‑Philippe Lapierre‑Boire,Mohammad Jahazi 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.3

The effect of Chromium (Cr) on the dynamic transformation (DT) of austenite to ferrite at temperatures up to 430 °C aboveAe3was studied in a medium-carbon low-alloy steel. Hot compression tests were performed using Gleeble 3800® thermomechanicalsimulator followed by microstructural examinations using electron microscopy (FESEM-EBSD). Driving forcecalculation using austenite flow stress and ferrite yield stress on an inverse absolute temperature graph indicated that Crincreases the driving force for the transformation of austenite to ferrite; however, when the influence of stress and thermodynamicanalysis are taken into account, it was observed that Cr increases the barrier energy and therefore, emerges as abarrier to the transformation. An analysis, based on lattice and pipe diffusion theories is presented that quantifies the role ofstress on the diffusivity of Cr and is compared with other the main alloying elements such as C, Si and Mn and its impact,positive or negative, on the DT barrier energy. Finally, a comparison is made on the differential effects of temperature andstress on the initiation of DT in medium-carbon low-alloy steels.

Approximations of solutions for a nonlocal fractional integro-differential equation with deviated argument

Alka Chadha,Dwijendra N. Pandey 한국전산응용수학회 2015 Journal of applied mathematics & informatics Vol.33 No.5

This paper investigates the existence of mild solution for a fractional integro-differential equations with a deviating argument and nonlocal initial condition in an arbitrary separable Hilbert space $H$ via technique of approximations. We obtain an associated integral equation and then consider a sequence of approximate integral equations obtained by the projection of considered associated nonlocal fractional integral equation onto finite dimensional space. The existence and uniqueness of solutions to each approximate integral equation is obtained by virtue of the analytic semigroup theory via Banach fixed point theorem. Next we demonstrate the convergence of the solutions of the approximate integral equations to the solution of the associated integral equation. We consider the Faedo-Galerkin approximation of the solution and demonstrate some convergence results. An example is also given to illustrate the abstract theory.

An Extended K-Means Algorithm using MapReduce Framework for Mixed Datasets

Anupama Chadha,Suresh Kumar 보안공학연구지원센터 2016 International Journal of Database Theory and Appli Vol.9 No.9

K-Means is a famous partition based clustering algorithm. Various extensions of K-Means have been proposed depending on the type of datasets being handled. Popular ones include K-Modes for categorical data and K-Prototype for mixed numerical and categorical data. The K-Means and its extensions suffer from one major limitation that is dependency on prior input of number of clusters K. Sometimes it becomes practically impossible to correctly estimate the optimum number of clusters in advance. Various ways have been suggested in literature to overcome this limitation for numerical data. But for categorical and mixed data work is still in progress. In this paper, we introduce a new algorithm based on the K-Means that takes mixed dataset as an input and generates appropriate number of clusters on the run using MapReduce programming style. The new algorithm not only overcomes the limitation of providing the value of K initially but also reduces the computation time using MapReduce framework.

Microtextural Characterization of Additively Manufactured SS316L After Hot Isostatic Pressing Heat Treatment

Kanwal Chadha,Yuan Tian,John Spray,Clodualdo Aranas 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.1

Microtextural characterization using electron backscatter difraction analysis was performed on laser powder bed fusion manufactured SS316L (SS316L). The crystallographic textures of as-printed (AP) and hot isostatic pressed (HIP) samples havebeen determined using orientation distribution function maps. The AP sample consists of mostly<110>||BD and<100>||BDfber textures without any clear presence of twins. Conversely, the HIP sample featured<110>||BD and<111>||BD grains. The formation of<111>||BD texture was due to the deformation associated with the HIP process. Moreover, HIP generateda signifcant fraction of coincident site lattice Σ3 boundaries due to the low stacking fault energy of SS316L. These twinboundaries allow considerable plasticity during subsequent deformation. The spacing of deformation twins is wider (1–5 μm)compared to the subgrain boundaries (0.2–0.7 μm). Kernel Average Misorientation maps depict the occurrence of dynamicrecrystallization, which is assisted by deformation twinning. The results explain the increased ductility of LPBF-produced,HIP processed SS316L without sacrifce to its tensile strength.

Recent progress and growth in biosensors technology: A critical review

Utkarsh Chadha,Preetam Bhardwaj,Rushali Agarwal,Priyanshi Rawat,Rishika Agarwal,Ishi Gupta,Mahek Panjwani,Shambhavi Singh,Chirag Ahuja,Senthil Kumaran Selvaraj,Murali Banavoth,Prashant Sonar,Badrish B 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.109 No.-

Crucial exploitation of biosensors has attained dominant significance in the meadow of drug innovation,drug identification, bio-remedy, food protection principles, security, protection, and ecological examination. It has direct to the innovation of specific and authoritative diagnostic tools that employ biologicalsensing elements as biosensors. Glucometers employ oxygen or hydrogen peroxide electrochemicalrecognition utilizing immobilized glucose oxidase electrodes, showing biosensors’ invention. Currentadvances in biological methods and instrumentation relating to fluorescence tags to nano-materials haveincreased the responsive limit of biosensors. The use of aptamers or nucleotides, antibodies, peptidearrays, and molecule imprinted polymers offer tools to build up novel biosensors over the classicalmethod. Integrated methods offer an improved perception for a buildup of precise and responsive biosensorswith high regenerative potentials. Various biosensors ranging from nanomaterials polymers tomicrobes have more comprehensive potential applications. Combining multifaceted approaches to designbiosensors that comprise the prospective for different usage is reasonably significant. In light of this, thisreview provides an overview of different types of biosensors being used, ranging from electrochemicaland fluorescence tagged, nanomaterials, silica or quartz, and microbes for various biomedical and environmentalapplications with the future outlook of biosensor technology.

Gratitude Without a Self

Monima Chadha,Shaun Nichols 성균관대학교 유교문화연구소 2023 儒敎文化硏究(中文版) Vol.- No.40

Gratitude plays a critical role in our social lives. It helps to build and strengthen relationships, and it enhances wellbeing. Gratitude is typically thought of as involving oneself having a positive feeling towards another self. But this kind of self-to-self gratitude seems to be at odds with the central Buddhist view that there is no self. Feeling gratitude to someone for some past generosity seems mis­placed since there is no continuing self who both performed the generous action and is now the recipient of gratitude. In this paper, we explore how the Buddhist might respond to this problem. In response, Buddhists characterize a kind of gratitude (anumodanā) that is not fully propositional, but nor is it a notion that critically implicates the problematic concept of self. Anumodanā (literally rejoicing in good deeds of another) is best thought of as an expression of sympathetic joy (mudita) which is classified among the “sublime abidings” or “perfections” in Buddhism. In this paper we explain the notion of anumodanā and its functioning in the context of dāna (gift-giving or almsgiving in the Buddhist monastic context) to explain how it recovers some of the benefits of our ordinary reactive attitude of gratitude without implicating the self.

An Efficient K-Means Algorithm and its Benchmarking against other Algorithms

Anupama Chadha,Suresh Kumar 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.11

K-Means is a widely used partition based clustering algorithm famous for its simplicity and speed. It organizes input dataset into predefined number of clusters. K-Means has a major limitation -- the number of clusters, K, need to be pre-specified as an input. Pre-specifying K in the K-Means algorithm sometimes becomes difficult in absence of thorough domain knowledge, or for a new and unknown dataset. This limitation of advance specification of cluster number can lead to “forced” clustering of data and proper classification does not emerge. In this paper, a new algorithm based on the K-Means is developed. This algorithm has advance features of intelligent data analysis and automatic generation of appropriate number of clusters. The clusters generated by the new algorithm are compared against results obtained with the original K-Means and various other famous clustering algorithms. This comparative analysis is done using sets of real data.

Effect of Double Hit Hot Deformation on the Evolution of Dynamically Transformed Ferrite

K. Chadha,C. Aranas Jr.,M. Jahazi 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.11

Double-hit hot compression tests were carried on medium-carbon low-alloy steels using Gleeble 3800® thermomechanicalsimulator. The experiments were performed at strain rates of 0.25 and 0.5 s−1 and temperatures of 1150 and 1200 °C withinterpass times of 5, 15, and 25 s. The onset of critical stresses for dynamic transformation (DT) for both first and second hitwere detected using the double-differentiation method. It was found that the critical stress for DT increased with a decreasein temperature and an increase in strain rate. The presence of dynamically transformed ferrite was observed and quantifiedusing electron-backscatter diffraction, kernal average misorientation, and grain boundary maps. Then, a thermodynamicanalysis was carried out using JmatPro software. A method of determining the change in Gibbs energy during DT phenomenonis proposed for double hit deformation.