Analysis of Fluorescence Quenching of Coumarin Derivative under Steady State and Transient State Methods

2021 ◽  
Author(s):  
V. V. Koppal ◽  
Raveendra Melavanki ◽  
Raviraj Kusanur ◽  
N. R. Patil
Keyword(s):  
Steady State ◽  
Fluorescence Quenching ◽  
Transient State ◽  
Coumarin Derivative

Effect of solvent polarity on the fluorescence quenching of TMC molecule by aniline in benzene–acetonitrile mixtures

2016 ◽  
Vol 94 (11) ◽  
pp. 1125-1132 ◽  
Author(s):  
Ashok H. Sidarai ◽  
Vani R. Desai ◽  
Shirajahammad M. Hunagund ◽  
Mahantesha Basanagouda ◽  
Jagadish S. Kadadevarmath
Keyword(s):  
Fluorescence Quenching ◽  
Rate Constants ◽  
Transient State ◽  
Solvent Polarity ◽  
Coumarin Derivative ◽  
Solvent Mixtures ◽  
Positive Deviation ◽  
Diffusion Limited ◽  
Quenching Process ◽  
Volmer Plot

The fluorescence quenching of coumarin derivative, 6-methoxy-4-p-tolyloxymethyl-chromen-2-one by aniline is carried out in different solvent mixtures of benzene and acetonitrile at room temperature. The quenching is found to be appreciable and a positive deviation from linearity is observed in the Stern–Volmer plot in all the solvent mixtures. Various rate constants for fluorescence quenching processes have been estimated using a sphere of action static quenching model and a finite sink approximation model. From the positive deviation of linear Stern–Volmer plots and dependence of rate constants on the polarity of the solvents, it has been inferred that the quenching process is diffusion-limited, and static as well as dynamic quenching processes are responsible for the observed positive deviation in the Stern–Volmer plot. Further, both models have been found to agree well with transient state also in pure acetonitrile and benzene solvents.

scholarly journals Multi-Machine Repairable System with One Unreliable Server and Variable Repair Rate

Mathematics ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1299
Author(s):  
Shengli Lv
Keyword(s):  
Steady State ◽  
Transient State ◽  
Repairable System ◽  
Repair Rate ◽  
Numerical Illustration ◽  
Transform Method ◽  
Unreliable Server ◽  
Busy Time ◽  
The Mean ◽  
Mean Time

This paper analyzed the multi-machine repairable system with one unreliable server and one repairman. The machines may break at any time. One server oversees servicing the machine breakdown. The server may fail at any time with different failure rates in idle time and busy time. One repairman is responsible for repairing the server failure; the repair rate is variable to adapt to whether the machines are all functioning normally or not. All the time distributions are exponential. Using the quasi-birth-death(QBD) process theory, the steady-state availability of the machines, the steady-state availability of the server, and other steady-state indices of the system are given. The transient-state indices of the system, including the reliability of the machines and the reliability of the server, are obtained by solving the transient-state probabilistic differential equations. The Laplace–Stieltjes transform method is used to ascertain the mean time to the first breakdown of the system and the mean time to the first failure of the server. The case analysis and numerical illustration are presented to visualize the effects of the system parameters on various performance indices.

Thermo-structural analysis of a honeycomb-type volumetric absorber for concentrated solar power applications

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Masoud Behzad ◽  
Benjamin Herrmann ◽  
Williams R. Calderón-Muñoz ◽  
José M. Cardemil ◽  
Rodrigo Barraza
Keyword(s):  
Heat Transfer ◽  
Thermal Stress ◽  
Steady State ◽  
Discrete Model ◽  
Continuum Model ◽  
Transient State ◽  
Operating Conditions ◽  
Steady State Condition ◽  
Content Type ◽  
The Continuum

Purpose Volumetric air receivers experience high thermal stress as a consequence of the intense radiation flux they are exposed to when used for heat and/or power generation. This study aims to propose a proper design that is required for the absorber and its holder to ensure efficient heat transfer between the fluid and solid phases and to avoid system failure due to thermal stress. Design/methodology/approach The design and modeling processes are applied to both the absorber and its holder. A multi-channel explicit geometry design and a discrete model is applied to the absorber to investigate the conjugate heat transfer and thermo-mechanical stress levels present in the steady-state condition. The discrete model is used to calibrate the initial state of the continuum model that is then used to investigate the transient operating states representing cloud-passing events. Findings The steady-state results constitute promising findings for operating the system at the desired airflow temperature of 700°C. In addition, we identified regions with high temperatures and high-stress values. Furthermore, the transient state model is capable of capturing the heat transfer and fluid dynamics phenomena, allowing the boundaries to be checked under normal operating conditions. Originality/value Thermal stress analysis of the absorber and the steady/transient-state thermal analysis of the absorber/holder were conducted. Steady-state heat transfer in the explicit model was used to calibrate the initial steady-state of the continuum model.

scholarly journals Sorption/Diffusion Contributions to the Gas Permeation Properties of Bi-Soft Segment Polyurethane/Polycaprolactone Membranes for Membrane Blood Oxygenators

Membranes ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 8
Author(s):  
Tiago M. Eusébio ◽  
Ana Rita Martins ◽  
Gabriela Pon ◽  
Mónica Faria ◽  
Pedro Morgado ◽  
...  
Keyword(s):  
Steady State ◽  
Soft Segment ◽  
Time Lag ◽  
Transient State ◽  
Gas Permeation ◽  
Dominant Factor ◽  
Atmospheric Gases ◽  
Equilibrium Conditions ◽  
Permeability Coefficients ◽  
Permeation Properties

Due to their high hemocompatibility and gas permeation capacity, bi-soft segment polyurethane/polycaprolactone (PU/PCL) polymers are promising materials for use in membrane blood oxygenators. In this work, both nonporous symmetric and integral asymmetric PU/PCL membranes were synthesized, and the permeation properties of the atmospheric gases N2, O2, and CO2 through these membranes were experimentally determined using a new custom-built gas permeation apparatus. Permeate pressure vs. time curves were obtained at 37.0 °C and gas feed pressures up to 5 bar. Fluxes, permeances, and permeability coefficients were determined from the steady-state part of the curves, and the diffusion and sorption coefficients were estimated from the analysis of the transient state using the time-lag method. Independent measurements of the sorption coefficients of the three gases were performed, under equilibrium conditions, in order to validate the new setup and procedure. This work shows that the gas sorption in the PU/PCL polymers is the dominant factor for the permeation properties of the atmospheric gases in these membranes.

Analysis of fluorescence quenching of coumarin derivative dye using Stern-Volmer plots

2019 ◽  
Author(s):  
Omnath Patil ◽  
P. K. Ingalagondi ◽  
G. B. Mathapati ◽  
S. M. Hanagodimath
Keyword(s):  
Fluorescence Quenching ◽  
Coumarin Derivative

On the GIX/G/∞ system

1990 ◽  
Vol 27 (3) ◽  
pp. 671-683 ◽  
Author(s):  
L. Liu ◽  
B. R. K. Kashyap ◽  
J. G. C. Templeton
Keyword(s):  
Steady State ◽  
Shot Noise ◽  
Continuous Time ◽  
Transient State ◽  
System Size ◽  
Noise Process ◽  
Shot Noise Process ◽  
Special Cases

By using a shot noise process, general results on system size in continuous time are given both in transient state and in steady state with discussion on some interesting results concerning special cases. System size before arrivals is also discussed.

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