Preparation of Copper based Composite for Catalytic Reduction of 4-Nitro Phenol in Ambient Condition

A facile synthesis of copper oxide decorated reduced Graphene oxide using ultrasonication is reported here. This nanocomposite exhibit very high efficiency in the reduction of p-Nitrophenol to the corresponding Amine. Different concentrations of p-nitrophenol have been used to test the catalytic efficiency of prepared catalyst with sodium borohydride and it is found that it is successfully reducing higher concentrations of this compound

Data Collection Survey on Forest Conservation in Mahavir Swami Wildlife Sanctuary for Addressing Climate Change

Tropical forest serves as an important pivotal role in terrestrial biological diversity. The tropical forest acts as munificence for the life forms living in the tropics, by providing habitat conditions and natural resources. Tree parameter measurement is an important part of forest resource monitoring. The Data Collection Survey on Forest Conservation aims to provide a comprehensive analysis of the current state of forests and evaluate the effectiveness of conservation efforts. This survey integrates advanced data collection methods, including remote sensing and Geographic Information Systems (GIS), to monitor forest health, biodiversity, and threats. Key findings highlight critical areas of biodiversity that require targeted conservation, the pervasive threats from illegal logging and climate change, and the significance of community involvement in conservation initiatives. This study makes an attempt to data collection surveying methods to assess forest management in Mahavir Swami Wildlife Sanctuary (MSWS), Lalitpur, UP, India, using Sentinel-2A sensor data. We selected tree samples from thirty transects in MSWS through random sampling. A method of collecting tree measurement factors based on height and DBH with a variety of high-precision methods is proposed. The data collection survey used in this study can help forest managers, environmentalist, and conservationist for formulating policies for management of forest ecosystem at various scales

NUMERICAL INVESTIGATION OF ON-POWER REFUELING IN A NATURAL CIRCULATION BOILING WATER REACTOR

ABSTRACT Most two-phase heat exchangers consist of multiple parallel boiling channels, and studies concerning multi-channel instabilities in boiling systems are of significant interest. The natural circulation boiling water reactor (NCBWR) considered in the present work is a pressure tube type boiling light water cooled and heavy water moderated reactor. The primary heat transport loop, comprising a number of parallel channels, is modeled by RELAP5/MOD3.4. The effects of on-power refueling on the flow rate and stability of the system are investigated. The conditions under which a sustainable flow rate can be maintained during on-power refueling are explored. It is observed that during on-power refueling, a near-stagnation condition or low-velocity reverse flow can occur, the possibility of reverse flow being higher at low pressures and low powers

Highlighting the Compound Risk of COVID-19 and Environmental Pollutants Using Geospatial Technology

The new COVID-19 coronavirus disease has emerged as a global threat and not just to human health but also the global economy. Due to the pandemic, most countries affected have therefore imposed periods of full or partial lockdowns to restrict community transmission. This has had the welcome but unexpected side effect that existing levels of atmospheric pollutants, particularly in cities, have temporarily declined. As found by several authors, air quality can inherently exacerbate the risks linked to respiratory diseases, including COVID-19. In this study, we explore patterns of air pollution for ten of the most affected countries in the world, in the context of the 2020 development of the COVID-19 pandemic. We find that the concentrations of some of the principal atmospheric pollutants were temporarily reduced during the extensive lockdowns in the spring. Secondly, we show that the seasonality of the atmospheric pollutants is not significantly affected by these temporary changes, indicating that observed variations in COVID-19 conditions are likely to be linked to air quality. On this background, we confirm that air pollution may be a good predictor for the local and national severity of COVID-19 infections.The authors acknowledge financial support from the Spanish Government, Grant RTI2018-354 094336-B-I00 (MCIU/AEI/FEDER, UE), the Spanish Carlos III Health Institute, COV 20/01213, and the Basque Government, Grant IT1207-19

Analysis of Instabilities, Nonlinear Oscillations and Startup Transients in Advanced Nuclear Reactors

Safety concerns for nuclear reactors necessitate analysis of instabilities that may occur during their startup or normal operation. Such analysis can be done exhaustively through computationally inexpensive reduced-order models using one-dimensional and lumped parameter approaches. While linear stability analysis gives information about the response of a dynamical system to small perturbations about its normal operating condition, analysis of nonlinear dynamics and bifurcations reveals the system behaviour in the presence of large perturbations. Transients occurring during the startup process involve large changes in system variables and have to be analysed accordingly. In this lecture, one-dimensional time-dependent mathematical modelling of boiling systems and supercritical fluid systems will be discussed along with lumped parameter modelling for linear and nonlinear stability analysis. Methods for analysis of linear and nonlinear oscillations and startup transients will be explained. Two advanced nuclear reactors — namely, the natural circulation boiling water reactor and the supercritical water-cooled reactor — will be considered for case studies. Mathematical modelling of these reactors — using the lumped parameter approach and the one-dimensional system code RELAP5/MOD3.4 — will be described. Using these models, the following studies will be discussed: linear stability analysis and parametric effects, nonlinear dynamics and bifurcations, startup transients and their time-series analysis

Numerical Computation of One-Dimensional Unsteady Two-Phase Flow Using HEM Model and IAPWS IF-97 Equations of State

Numerical simulation of transients in two-phase flow is crucial to simulate accident-like and aberrant conditions of nuclear reactors for safety analysis. A considerable number of such problems can be treated as one-dimensional with significant reduction in complexity without much loss in applicability. Most commercial thermal hydraulic codes are based on the two-fluid model, which solves balance equations for each phase and also accounts for thermodynamic non-equilibrium between the phases. However, the homogenous equilibrium mixture (HEM) model of two-phase flow can be employed to develop simple and efficient codes for transient simulations, using which extensive parametric studies can be carried out. In the present work, a code for numerical computation of unsteady one-dimensional two-phase flow has been developed and reactor transients have been simulated. The governing equations were obtained by the HEM model and were decoupled and approximated using the sectionalized compressible flow (SC) model and the momentum integral (MI) model. The equations of state used in the code are based on IAPWS Industrial Formulation-97. Pressure and heat flux transients for PWR and BWR were simulated with the code and compared with those reported in the literature. Further numerical simulations with the code were carried out to predict the transient response of nuclear reactors to various perturbations.</jats:p