49 research outputs found
Molecular Transients in Photoactive Heterocyclic Systems
No full textThe journey from light-induced excitation of a photoactive molecule to the formation of a stable photoproduct unfolds through a sequence of complex transformations within the molecular system. These transformations are governed by ultrafast processes and short-lived intermediates or transient species, which are crucial to the photoprocess. Studying these intermediates is vital not only for understanding the fundamental light-matter interactions that underlie natural optical phenomena but also for enabling the design of photochemical and photophysical reactions across diverse fields of application. Optical spectroscopic methods are commonly used to gather experimental evidence of these phenomena. Although these methods identify the intermediates based on their energy signatures, a proper characterization of the electronic structure remains elusive. This thesis delves into sophisticated quantum chemical frameworks, supported by multiple studies, to elucidate the mechanism and architecture involved in characterizing the short-lived molecular transients. The studies addressed in the thesis highlight the rich photochemistry of heterocyclic compounds through theoretical dynamical modeling and spectral simulations. In the first part, the non-adiabatic effects in photoexcited thiopyridone are explored. A collective theoretical and experimental investigation describes the molecular evolution during the ultrafast process and the observed variations across its constitutional isomers. The possibility of formation of a molecular excimer is also explored. The second part focuses on imidazole to simulate the electronic and structural changes that lead to proton transfer, with particular attention given to the local effects that influence the overall characteristics
Recommended from our members
Packet pacer : an application over NetBump
No full textMany ideas for adding innovative functionalities to networks require either modifying packets or performing alternative queuing to packets in flight on the data- plane. Modifications to existing network is difficult and often faced with hindrance like ease of deployability and ability to test with production-like traffic. NetBump is a platform for experimenting, evaluating and deploying these ideas with minimal intrusiveness, while leaving the switches and endhosts unmodified. In this thesis, we evaluate TCP packet pacing as an application over NetBump. We propose a modified token bucket implementation which accurately estimates the token requirement for sustained well-paced TCP flow, thus smoothing the bursty behavior. We were able to able to monitor various crucial features of the TCP flow and take informed decisions to pace the out going flow. Finally, we perform micro-benchmarks to see the effect of pacing. In general, our packet pacer implementations reduces the number of buffer overflows. Specifically, the modified token bucket implementation performs the best with zero buffer overflow
Molecular Transients in Photoactive Heterocyclic Systems
No full textThe journey from light-induced excitation of a photoactive molecule to the formation of a stable photoproduct unfolds through a sequence of complex transformations within the molecular system. These transformations are governed by ultrafast processes and short-lived intermediates or transient species, which are crucial to the photoprocess. Studying these intermediates is vital not only for understanding the fundamental light-matter interactions that underlie natural optical phenomena but also for enabling the design of photochemical and photophysical reactions across diverse fields of application. Optical spectroscopic methods are commonly used to gather experimental evidence of these phenomena. Although these methods identify the intermediates based on their energy signatures, a proper characterization of the electronic structure remains elusive. This thesis delves into sophisticated quantum chemical frameworks, supported by multiple studies, to elucidate the mechanism and architecture involved in characterizing the short-lived molecular transients. The studies addressed in the thesis highlight the rich photochemistry of heterocyclic compounds through theoretical dynamical modeling and spectral simulations. In the first part, the non-adiabatic effects in photoexcited thiopyridone are explored. A collective theoretical and experimental investigation describes the molecular evolution during the ultrafast process and the observed variations across its constitutional isomers. The possibility of formation of a molecular excimer is also explored. The second part focuses on imidazole to simulate the electronic and structural changes that lead to proton transfer, with particular attention given to the local effects that influence the overall characteristics
Simulating non-adiabatic dynamics of photoexcited phenyl azide : Investigating electronic and structural relaxation en route to the formation of phenyl nitrene
No full textExcited state molecular dynamics simulations of the photoexcited phenyl azide have been performed. The semi-classical surface hopping approximation has enabled an unconstrained analysis of the electronic and nuclear degrees of freedom which contribute to the molecular dissociation of phenyl azide into phenyl nitrene and molecular nitrogen. The significance of the second singlet excited state in leading the photodissociation has been established through electronic structure calculations, based on multi-configurational schemes, and state population dynamics. The investigations on the structural dynamics have revealed the N−N bond separation to be accompanied by synchronous changes in the azide N−N−N bond angle. The 100 fs simulation results in a nitrene fragment that is electronically excited in the singlet manifold
Automatic Detection of Oral Squamous Cell Carcinoma from Histopathological Images of Oral Mucosa Using Deep Convolutional Neural Network
No full textWorldwide, oral cancer is the sixth most common type of cancer. India is in 2nd position, with the highest number of oral cancer patients. To the population of oral cancer patients, India contributes to almost one-third of the total count. Among several types of oral cancer, the most common and dominant one is oral squamous cell carcinoma (OSCC). The major reason for oral cancer is tobacco consumption, excessive alcohol consumption, unhygienic mouth condition, betel quid eating, viral infection (namely human papillomavirus), etc. The early detection of oral cancer type OSCC, in its preliminary stage, gives more chances for better treatment and proper therapy. In this paper, author proposes a convolutional neural network model, for the automatic and early detection of OSCC, and for experimental purposes, histopathological oral cancer images are considered. The proposed model is compared and analyzed with state-of-the-art deep learning models like VGG16, VGG19, Alexnet, ResNet50, ResNet101, Mobile Net and Inception Net. The proposed model achieved a cross-validation accuracy of 97.82%, which indicates the suitability of the proposed approach for the automatic classification of oral cancer data
GSM Based Display ToolKit
No full textWireless communication has announced its arrival on big stage and the world is going mobile. We want to control everything and without moving an inch. This remote control of appliances is possible through Embedded Systems. The use of “Embedded System in Communication” has given rise to many interesting applications that ensures comfort and safety to human life. The main aim of the project will be to design a SMS driven automatic display toolkit which can replace the currently used programmable electronic display. It is proposed to design receive cum display toolkit which can be programmed from an authorized mobile phone. The message to be displayed is sent through a SMS from an
authorized transmitter. The toolkit receives the SMS, validates the sending Mobile Identification Number (MIN) and displays the desired information after necessary code conversion. The system is made efficient by using ‘clone’ SIMs of same MIN in a geographical area so that the same SMS can be received by number of display boards in a locality using techniques of time division multiple access. Started of as an instantaneous News display unit, we have improved upon it and tried to take advantage of the computing capabilities of microcontroller. We envision a toolkit that will not only
display message but also can be used to do some mechanical work
Evaluation of Mechanical Properties of Sabai Grass (Eulaliopsis binata) Fibers and Epoxy Resin Composite Laminates Using Fly Ash as Filler Material
No full textThe integration of sabai grass fibers and fly ash in epoxy resin combines the strengths of both materials for developing a tailor-made composite laminate that balances performance, sustainability, and cost-efficiency. This innovative blend of natural fibers and industrial waste promotes environmental conservation. The laminates produced could also be used in diverse industrial and structural applications. This study investigated the mechanical properties of composite laminates reinforced with sabai grass fibers, fly ash filler, and epoxy resin as the matrix. In this work, the hand lay-up method was used to fabricate composites with two stacking configurations ((0°/0°/0°/0°) and (0°/90°/90°/0°)) and filler contents of 1.5 wt.%, 3 wt.%, and 5 wt.%. Various weight fractions of fly ash filler and sabai grass fiber were integrated into the epoxy resin to evaluate their impact on tensile strength, flexural strength, and hardness. The experimental results indicate that adding fly ash significantly improves the composite’s hardness to 27 HV in the composites containing 5 wt.% filler, while sabai grass fibers contribute to enhanced tensile strength and flexural strength. The composites with (0°/0°/0°/0°) fibers and 5 wt.% filler showed a higher tensile strength of 63.5 MPa and flexural strength of 118.5 MPa. The fractured sample was analyzed with the help of FESEM images. The XRD analysis confirmed the presence of fly ash components suitable for forming a bond with epoxy. EDX was conducted to determine the elemental composition of the fly ash. FTIR analysis verified the removal of impurities such as dust, dirt, and lignin from the fiber surface following NaOH treatment
Corrigendum to "How and where to use super-capacitors effectively, an integration of review of past and new characterization works on super-capacitors" [J. Energy Storage, 27 (2020), Article 101044]
No full text
