Lakshminath Bezbaroa Central Library Digital Repository

Welcome to the Institutional Digital Repository of Lakshminath Bezbaroa Central Library.

  • This digital archive comprised of the Institutes' intellectual output.
  • It manages, preserves & makes available the academic works of faculty and research scholars.
  • It is established to facilitate deposit of digital content of scholarly or heritage nature.
  • Allowing academics & their departments to share & preserve contents in a managed environment.
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Recent Submissions

Design and Development of Hybrid Nanomaterials for Efficient Photocatalysis
(2024) Devi, Thongam Debika
Water is our life and its quality degradation has imposed a major threat to the health and environment with the emerging contaminants. Photocatalytic advanced oxidation processes (AOP) using reactive oxygen species (OH¯, •OH, H2O2, HO2•, O2•¯, O22¯) provide complete degradation of these persistent pollutants by using nanomaterials triggered by light absorption. However, its real-time application is limited by the use of high-power light sources to trigger the reaction and its limited performance. Thus, this thesis focuses on understanding and addressing these bottlenecks by― (a) designing and developing a sunlight-responsive photocatalyst to harvest natural sunlight, (b) developing heterostructure photocatalysts for enhanced efficiency by developing interfacial charge transfer, and (c) studying and discovering ways to enhance charge transfer by manipulating heterostructure photocatalyst responsive to natural sunlight. To achieve efficient photocatalysis, different sunlight-responsive photocatalysts were synthesized by varying― synthesis mediums and methods introducing surface defects and producing different nanoparticle morphologies. The dependence of the charge transfer, charge carrier lifetimes, surface structures, induced defects, and morphologies on the photocatalytic efficiencies were discussed elaborately. Variable ZnO samples were synthesized using DMF or DEG solvents using solvothermal and chemical synthesis methods showing different properties― morphologies, surface, and chemical properties. The influence of the charge transfer pathways in the photocatalytic efficiencies is discussed and explored with different charge transfer methods― self-assembled ZnO nanoparticles on three electronically different SWCNTs (metallic-SWCNT/ZnO, semiconducting-SWCNT/ZnO, and pristine-SWCNT/ZnO); Type I ZnO/Fe3O4 and Type II ZnO/TiO2 composite heterostructures; g-C3N4 & Z-scheme g-C3N4/ZnO composites, and other composites― g-C3N4/SWCNT, and g-C3N4/ZnO/SWCNT. By taking RhB as a model pollutant, these nanoparticles were used as the floating photocatalyst by coating on the face-mask fabric showing variable efficiencies up to 99% of 10 ppm RhB degradation within the 100 min natural sunlight exposure.
Acoustic Charge Transport in Organic Semiconductors using Surface Acoustic Wave Devices
(2024) Mishra, Himakshi
A surface acoustic wave (SAW) is a periodic deformation of the surface of an elastic material propagating at the surface primarily as a linear wave front. Despite the fact that their existence had already been established by Lord Rayleigh in 1885, it wasn't until 1965, through the development of the interdigital transducer (IDT), that they were first utilised for various applications. It is now feasible to stimulate and detect SAWs on a piezoelectric surface in an effective manner. It is established that SAW devices have a very broad range of applications in several fields. Professional radar and communications systems extensively use SAW delay lines, band pass filters, resonators, oscillators, and matched filters. SAW can also be employed as a pressure, humidity, and temperature sensor for chemical sensing and analysis purposes. SAW has very low velocity and narrow wavelengths, reducing size and weight and hence, can be mass manufactured. When a semiconductor comes into interaction with SAW, the acoustic deformations induced by SAW have a significant impact on the semiconductor's energy bands and, consequently, its electrical characteristics. SAW-induced band edge modulation leads to the spatial separation of charge carriers of a semiconductor. Furthermore, the energy and momentum carried by SAW are transmitted to charge carriers resulting in a dragging force on them. This phenomenon is known as the acoustoelectric effect, and the transport caused by this effect is termed acoustic charge transport (ACT). The process of ACT has been demonstrated by several researchers in inorganic semiconductors either by injecting carriers through an input bias or optically generating carriers. Organic semiconductors are increasingly being used as the active layer in a wide variety of innovative technologies due to their solution-processability, lightweight, and flexibility. In contrast to inorganic semiconductors, organic materials form a polycrystalline layer, and their charge transport is mostly limited by grain boundaries. Numerous studies have been done, throughout the past few years, to investigate the factors affecting and contributing to the charge transport of organic semiconductors. However, the interaction of an acoustic wave with these materials has not been reported yet. The primary objective of the thesis is to observe the charge transport of ambipolar electrons and holes in organic semiconductor films by means of acoustic waves and to investigate potential acousto-optic applications that may result from this interaction.
On the Darboux Polynomials and Simplicity of Polynomial Derivations
(2024) Kesarwamy, Ashish Kumar
Derivations and Darboux polynomials are useful methods to study polynomial or rational differential system. In the vocabulary of differential algebra, Darboux polynomials coincides with generators of polynomial differential ideals, that is f∈k [ x1 ,…, xn] is a Darboux polynomial iff f ≠ 0 and the ideal ( f ) is differential. The present thesis studies certain classes of derivations having no Darboux polynomials with monomial cofactor. Another important notion in commutative algebra, simple derivations has also been studied in this thesis. Simple derivationsplay an important role in numerous problems. This thesis studies certain classes of derivations that are simple. In Chapter-1, we talk about definitions, notations and basic facts. In Chapter-2, we study a class of derivations having no Darboux polynomial with monomial cofactor. In Chapter-3, we study simplicity of certain polynomial derviations in the polynomial ring k [ x , y ]. In Chapter-4, we generalize the results obtained in Chapter-3 in more than two variables, i.e., we talk about few classes of simple derivations of the polynomial ring k [ x1 ,…, xn ]. In this Chapter- 5, We pose some problems arising out of the work carried out in this thesis.
Evaluation of Out-of-Breath Speech Using Machine Learning Approaches
(2024) Sahoo, Sibasis
Stress alters the speech production mechanism. Factors like emotion, cognitive load, pathology, noisy condition (Lombard effect), physical load, sleep deprivation, etc., affect speech production. Among these, speech under emotional, noisy, and pathological conditions are investigated extensively. Little light has been shed on speech under physical load conditions, called out-of-breath speech. Such evaluation of out-of-breath conditions can be used in context-aware speech interfaces to estimate the workload level, exercise intensity of an athlete, and physical fitness of a person.
Design and Implementation of a File System and a Distributed KV store on Non Volatile Memory
(2024) Kalita, Chandan
Non-volatile memory (NVRAM) is becoming available. With the availability of hybrid DRAM and NVRAM memory on the memory bus of CPUs, a number of experimental file systems on NVRAM have been designed and implemented. In this thesis we present the design and implementation of a file system on NVRAM called DurableFS, which provides atomicity and durability of file operations to applications. It provides ACID properties to transactions involving multiple files. Due to the byte level random accessibility of memory, it is possible to provide these guarantees without much overhead. We use standard techniques like copy on write for data, and a redo log for metadata changes to build an efficient file system which provides durability and atomicity guarantees to transactions. Benchmarks on the implementation shows that there is only a 7% degradation in performance due to providing these guarantees.