44 research outputs found
An Overview of Charge Pump for Phase Lock Loop System for High Frequency Application.
Phase lock loop is fundamental buliding block of modern communication system. Phase lock loop are typically used to provide local oscillator function in radio reciver or transmitter. The design methodology and test result of charge pump structure for phase lock loop application are presented. The structure is composed to two charge/ discharge block. This paper provides study of various charge pump and discuss the technology that is used to design charge pump
Modelling UV response of biomolecules: from electronic structure to ab-initio dynamics.
The interaction of organic chromophores with light initiates ultrafast processes in the timescale of femtoseconds. An atomistic understanding of the mechanism driving such photoinduced reactions opens up the door to exploit them for our benefit. This thesis studies the interactions of ultraviolet light with the DNA/RNA molecules and the amino-acid tryptophan. Using some of the most accurate electronic structure methods and sophisticated environmental modelling, the works documented herein enable quantitative comparisons with cutting-edge experimental data. The relaxation pathways undertaken by the excited molecule are revealed through static and dynamical investigations of the excited-state potential energy surface. The profound role played by the dynamic response of the environment to guide the excitation in these timescales is addressed thoroughly
MOBILE NETWORKING FOR “SMART DUST” WITH RFID SENSOR NETWORKS
Large-scale networks of wireless sensors are becoming an active topic of research.. We review the key elements of the emergent technology of “Smart Dust” and outline the research challenges they present to the mobile networking and systems community, which must provide coherent connectivity to large numbers of mobile network nodes co-located within a small volume. Smart Dust sensor networks – consisting of cubic millimetre scale sensor nodes capable of limited computation, sensing, and passive optical communication with a base station – are envisioned to fulfil complex large scale monitoring tasks in a wide variety of application areas. RFID technology can realize “smart-dust” applications for the sensor network community. RFID sensor networks (RSNs), which consist of RFID readers and RFID sensor nodes (WISPs), extend RFID to include sensing and bring the advantages of small, inexpensive and long-lived RFID tags to wireless sensor networks. In many potential Smart Dust applications such as object detection and tracking, fine-grained node localization plays a key role
Maximizing Savonius Turbine Performance using Kriging Surrogate Model and Grey Wolf-Driven Cylindrical Deflector Optimization
With the growing demand for power and the pressing need to shift towards
renewable energy sources, wind power stands as a vital component of the energy
transition. To optimize energy production, researchers have focused on design
optimization of Savonius-type vertical axis wind turbines (VAWTs). The current
study utilizes Unsteady Reynolds-Averaged Navier Stokes (URANS) simulations
using the sliding mesh technique to obtain flow field data and power
coefficients. A Kriging Surrogate model was trained on the numerical data of
randomly initialized data points to construct a response surface model. Then
Grey Wolf Optimization (GWO) algorithm was utilized to achieve global maxima on
this surface, using the turbine's power coefficient as the objective function.
A comparative analysis was carried out between simulation and experimental data
from prior studies to validate the accuracy of the numerical model. The
optimized turbine-deflector configuration showed a maximum improvement of
34.24% in power coefficient. Additionally, the GWO algorithm's effectiveness
was compared with Particle Swarm Optimization (PSO) and was found to be better
in most cases, converging towards the global maxima faster. This study explores
a relatively unexplored realm of metaheuristic optimization of wind turbines by
using deflectors, for efficient energy harvesting, presenting promising
prospects for enhancing renewable power generation.Comment: Accepted at 10th International and 50th National Conference on Fluid
Mechanics and Fluid Power (FMFP-2023): 6 pages, 12 figure
Two-dimensional electronic spectroscopy as a tool for tracking molecular conformations in DNA/RNA aggregates
A computational strategy to simulate two-dimensional electronic spectra (2DES) is introduced, which allows characterising ground state conformations of flexible nucleobase aggregates that play a crucial role in nucleic acid photochemistry
Environment-Driven Coherent Population Transfer Governs the Ultrafast Photophysics of Tryptophan
: By combining UV transient absorption spectroscopy with sub-30-fs temporal resolution and CASPT2/MM calculations, we present a complete description of the primary photoinduced processes in solvated tryptophan. Our results shed new light on the role of the solvent in the relaxation dynamics of tryptophan. We unveil two consecutive coherent population transfer events involving the lowest two singlet excited states: a sub-50-fs nonadiabatic La → Lb transfer through a conical intersection and a subsequent 220 fs reverse Lb → La transfer due to solvent-assisted adiabatic stabilization of the La state. Vibrational fingerprints in the transient absorption spectra provide compelling evidence of a vibronic coherence established between the two excited states from the earliest times after photoexcitation and lasting until the back-transfer to La is complete. The demonstration of response to the environment as a driver of coherent population dynamics among the excited states of tryptophan closes the long debate on its solvent-assisted relaxation mechanisms and extends its application as a local probe of protein dynamics to the ultrafast time scales
Modeling the high-energy electronic state manifold of adenine: Calibration for nonlinear electronic spectroscopy
The OpenMolcas Web: A Community-Driven Approach to Advancing Computational Chemistry
The developments of the open-source OpenMolcas chemistry software environment since spring 2020 are described, with a focus on novel functionalities accessible in the stable branch of the package or via interfaces with other packages. These developments span a wide range of topics in computational chemistry and are presented in thematic sections: electronic structure theory, electronic spectroscopy simulations, analytic gradients and molecular structure optimizations, ab initio molecular dynamics, and other new features. This report offers an overview of the chemical phenomena and processes OpenMolcas can address, while showing that OpenMolcas is an attractive platform for state-of-the-art atomistic computer simulations
Probing deactivation pathways of DNA nucleobases by two-dimensional electronic spectroscopy: first principles simulations
The global burden of cancer attributable to risk factors, 2010-19 : a systematic analysis for the Global Burden of Disease Study 2019
Background Understanding the magnitude of cancer burden attributable to potentially modifiable risk factors is crucial for development of effective prevention and mitigation strategies. We analysed results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 to inform cancer control planning efforts globally. Methods The GBD 2019 comparative risk assessment framework was used to estimate cancer burden attributable to behavioural, environmental and occupational, and metabolic risk factors. A total of 82 risk-outcome pairs were included on the basis of the World Cancer Research Fund criteria. Estimated cancer deaths and disability-adjusted life-years (DALYs) in 2019 and change in these measures between 2010 and 2019 are presented. Findings Globally, in 2019, the risk factors included in this analysis accounted for 4.45 million (95% uncertainty interval 4.01-4.94) deaths and 105 million (95.0-116) DALYs for both sexes combined, representing 44.4% (41.3-48.4) of all cancer deaths and 42.0% (39.1-45.6) of all DALYs. There were 2.88 million (2.60-3.18) risk-attributable cancer deaths in males (50.6% [47.8-54.1] of all male cancer deaths) and 1.58 million (1.36-1.84) risk-attributable cancer deaths in females (36.3% [32.5-41.3] of all female cancer deaths). The leading risk factors at the most detailed level globally for risk-attributable cancer deaths and DALYs in 2019 for both sexes combined were smoking, followed by alcohol use and high BMI. Risk-attributable cancer burden varied by world region and Socio-demographic Index (SDI), with smoking, unsafe sex, and alcohol use being the three leading risk factors for risk-attributable cancer DALYs in low SDI locations in 2019, whereas DALYs in high SDI locations mirrored the top three global risk factor rankings. From 2010 to 2019, global risk-attributable cancer deaths increased by 20.4% (12.6-28.4) and DALYs by 16.8% (8.8-25.0), with the greatest percentage increase in metabolic risks (34.7% [27.9-42.8] and 33.3% [25.8-42.0]). Interpretation The leading risk factors contributing to global cancer burden in 2019 were behavioural, whereas metabolic risk factors saw the largest increases between 2010 and 2019. Reducing exposure to these modifiable risk factors would decrease cancer mortality and DALY rates worldwide, and policies should be tailored appropriately to local cancer risk factor burden. Copyright (C) 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.Peer reviewe