Institutional Digital Repository (Indian Institute of Technology Kharagpu)

Roy, Saikat

Incorporating Conformational Complexities in the Study of Reaction Mechanisms

Rani, Priyanka

Synthesis, Fabrication and Characterization of Two-Dimensional Materials-Based Supercapacitors

Agrawal, Shubham

Thermo-Capillarity Induced Transport Phenomena in Microfluidic Domains

Jayaraman, Thirumagal

Computer-Assisted Diagnosis for Brain Atrophy Using CT and MR Images

Sengupta, Amrita

Chemomechanics of lithium-ion battery anode particles: 
Role of geometry and surface effects
Chemomechanics  refers  to  a  complex  interplay  of  chemical  and  mechanical  phenomena  inducing  and
influencing each other in a coupled way.  It  is  an integral  part  of  the mathematical  modelling of various
multiphysics problems ranging over a plethora of applications, one among which is the interaction occurring
inside the electrodes of a lithium-ion battery (LIB). The anode particles inside a LIB serve as an excellent
platform to demonstrate the coupled interactions resulting from the chemical diffusion of lithium (Li) atoms
and corresponding mechanical deformations of the anode particles. The urge for improved energy and power
density with the growing need for portable energy-storage devices has driven the search for alternate anode
materials that can replace the traditionally used graphite. Silicon, with a theoretical capacity ten times that of
graphite, is the best replacement. However, it comes with an impending characteristic of huge volumetric
expansion associated with Li insertion, and a subsequent contraction during Li dis-insertion. This frequent
change in  volume during each charging-discharging cycle  leads  to  mechanical  degradation,  and eventual
capacity fades. Strikingly, the usage of nanostructured anode particles meets this challenge considerably. But,
as  we  venture  into  nano-dimensions,  the  surface-to-volume  ratio  increases,  and  surface  stresses  become
significant.  Surface stresses, not only modulates the stress magnitudes within the anode particles but also
affect the overall performance of the anode particles. This study fundamentally addresses how the increasing
significance of surface stresses at such lower dimensions, form an integral part in deciding the morphology
and electro-chemo-mechanical performances of the anode particles used in Li-ion batteries. 
The thesis primarily deals with four problems: first, an improved chemomechanical framework considering
the dependence of the coefficient of compositional expansion on Li concentration, which is generally assumed
to  be  constant;  second,  a  finite  deformation  formulation  for  chemomechanical  interactions  within  nano-
structured, cylindrical Si anode particles considering surface stresses, and how the particle size and charging
rate modulate the magnitude of the surface stresses; third, the influence of surface stresses on the mechanical
and  electrochemical  performances  of  nano-structured,  cylindrical  Si  anode  particles  under  two  different
charging conditions: galvanostatic and potentiostatic; fourth, a generalized two-dimensional chemomechanical
framework considering nano-holes within an infinite matrix, examining the influence of surface stresses on
the morphology of these nano-holes, based on their sizes and proximity to the neighbouring holes.
Although the results and investigations are performed keeping in mind the lithiation/delithiation of Si anode
particles,  the  proposed  mathematical  frameworks  can  be  applied  to  other  situations  involving
chemomechanical  interactions.  Further,  these  frameworks  can  be  suitably  modified  to  computationally
analyse the behaviour of engineered materials before launching into costly manufacturing processes. These
models can be extended to interpret other Multiphysics problems which are analogous to chemomechanical
processes, like thermomechanical interactions, hydration-induced-swelling, etc.


Chemomechanics of Lithium-Ion Battery Anode Particles: Role of Geometry and Surface Effects

C, Chinmayee

Thesis Title: Development of Two-Dimensional Magnetic Transition Metal 
Tellurides for Energy Applications 
 
Abstract 
Transition metal di-chalcogenides (TMDCs) compose of both layered and non-layered materials. 
The layered materials can be easily cleaved into atomically thin layers from bulk crystals as they 
have weak van der Waals binding in between them. The cleaving process can also be extended for 
materials with a higher c/a ratio and are non-layered. Mechanical forces and acoustic vibrations 
are the two most common synthesis techniques employed to form two-dimensional (2D) structures. 
Amongst them Tellurium has a high atomic number (Z = 52) and exhibits large spin-orbit coupling, 
due to which the properties displayed by metal tellurides differ from their sulfide and selenide 
counterparts. The larger ionic radius and broader d-bands in tellurides results in smaller bandgaps. 
They easily form metal – metalloid complexes and are comparatively less toxic in nature.  
Magnetism in two-dimensional structures is as intriguing property that results in varied 
magnetic behaviors when thin downed to the atomic level. According to Merwin - Wagner 
theorem, for a 2D material, it is difficult to have long range magnetic ordering (d ≤ 3). Magnetic 
anisotropy (MAE) plays a major role in long range ordering at atomic levels. Extrinsic 2D 
magnetic materials which originate from external stimuli such as doping and strains find various 
room temperature applications. In this work we extend to explore few compositions of 2D 
transition metal tellurides (TMTs) consisting of manganese and chromium metal complexes 
(MnTe, MnTe2, Cr2Te3 and CrTe3). Multiple magnetic phase transitions were observed in the 2D 
material, which can help tune bandgap. The distance between atoms was varied via elastic strain, 
which is not possible in bulk structures. We observe shifts in Curie temperature (Tc) and Neel 
Temperature (TN) which is due to change in lattice structure. This is due to unbalanced spin 
majority and increased spin populations.  
We find applications of these 2D TMTs in room temperature spintronic application, 
observed non - thermal deicing due to ferromagnetic to paramagnetic transitions at room 
temperature, for energy efficient photodegradation of dyes and also explored their charge 
generation capabilities devising Flexible Nanogenerators.  


Development of Two-Dimensional Magnetic Transition Metal Tellurides for Energy Applications

Sengupta, Pradyut

Synthesis and Characterization of ZrB2-SiC Based Composites for Ultra-High Temperature Structural Applications

Pathak, Smriti

The Role of Emotion, Working Memory Capacity, and Decision Style in Decision-Making

Pal, Pijus Kanti

Brahmacaryāśramadharma: 
Towards Evolving a Students’ Code for Higher Institutions of Bhārata in the 
Light of NEP2020 
 
Abstract 
The National Education Policy (NEP2020) highlights the need to introduce students 
to Indian Knowledge Systems (IKS) along with their underlying worldview and 
value systems. In this context, this thesis seeks to evolve a students’ Code for Higher 
Institutions of Bhārata that will enable them to experience the optimum all-round 
development. 
 
In ancient Bhārata or India, life was divided into four stages or 
caturāśramas, of which brahmacaryāśrama referred to the first phase called student 
life. Each stage or āśrama was associated with specific Codes of Conduct known as 
dharma which consists of values and their corresponding practices to achieve the 
highest ideal in any situation. The concept of dharma, in this thesis, is used 
interchangeably with the acronym CODE which stands for Collective Oath for 
Development and Excellence.  
 
Sanskrit texts describe CODEs for students known as 
brahmacaryāśramadharma that had to be implemented in the Ancient Gurukula 
System (AGS). In more contemporary times, we find reflections of the same in the 
writings of modern Indian Seer-Educationists (SeE) like Swami Vivekananda, Sri 
Aurobindo and Rabindranath Tagore, in those of Indian Scholar-Educationists (ScE), 
Mahatma Gandhi, Sarvapalli Radhakrishnan, APJ Abdul Kalam as well as in 
NEP2020.  
 
The objectives of this thesis are to identify those values and practices 
prescribed for brahmacaryāśramadharma from literature review; to do a 
comparative study to see which values are universal and unique in them pertaining 
to the different periods they belong to; and finally, to evolve a CODE for Higher 
Institutions of Bhārata in the light of NEP2020. 
 
We have used a mixed methodology using the Literature Review Method and 
a qualitative approach with semi-structured interviews and surveys at designated 
institutions to understand the perceptions of contemporary students’ values and 
practices. Finally, we analysed the data obtained to identify the top nine overarching 
values and practices as navaratna CODE or the CODE of nine gems for students. It 
was observed that while NEP2020 recommends the practice of universal values for 
students of all institutions, this study indicates that every institution also has its own 
unique value system over and above the universal ones that were identified based on 
the study, depending on the nature of its academic focus, which can be evolved 
through the survey of the student population. 
 
Key words: NEP2020, dharma, Students’ CODE, brahmacaryāśramadharma,  


Brahmacaryāś Ramadharma: Towards Evolving a Students’ Code for Higher Institutions of Bhārata in the Light of NEP 2020

Lakshmi K, Sathya Uma

Climate Vulnerability Assessment and Farming System Model Development for Dryland Ecosystem in Southern India

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