scholarly journals Dependence of Calculated Postshock Thermodynamic Variables on Vibrational Equilibrium and Input Uncertainty

2017 ◽  
Vol 31 (3) ◽  
pp. 586-608 ◽  
Author(s):  
Matthew F. Campbell ◽  
Kyle G. Owen ◽  
David F. Davidson ◽  
Ronald K. Hanson
Keyword(s):  
Input Uncertainty ◽  
Thermodynamic Variables ◽  
Vibrational Equilibrium

Two-Dimensional Infrared Spectroscopy From the Gas to Liquid Phase: Density Dependent J-Scrambling, Vibrational Relaxation, and the Onset of Liquid Character

2019 ◽  
Author(s):  
Greg Ng Pack ◽  
Matthew Rotondaro ◽  
Parth Shah ◽  
Aritra Mandal ◽  
Shyamsunder Erramilli ◽  
...  
Keyword(s):  
Vibrational Energy ◽  
Rotational Relaxation ◽  
Vibrational Energy Relaxation ◽  
Pump Probe ◽  
Solution Dynamics ◽  
Supercritical Phase ◽  
Supercritical Solution ◽  
Asymmetric Stretch ◽  
Two Dimensional Infrared Spectroscopy ◽  
Vibrational Equilibrium

Ultrafast 2DIR spectra and pump-probe responses of the N2O n 3 asymmetric stretch in SF6 as a function of density from the gas to supercritical phase and liquid are reported. 2DIR spectra unequivocally reveal free rotor character at all densities studied in the gas and supercritical region. Analysis of the 2DIR spectra determines that J-scrambling or rotational relaxation in N2O is highly efficient, occurring in ~1.5 to ~2 collisions with SF6 at all non-liquid densities. In contrast, N2O n 3 vibrational energy relaxation requires ~15 collisions, and complete vibrational equilibrium occurs on the ~ns scale at all densities. An independent binary collision model is sufficient to describe these supercritical state point dynamics. The N2O n 3 in liquid SF6 2DIR spectrum shows no evidence of free rotor character or spectral diffusion. Using these 2DIR results, hindered rotor or liquid-like character is found in gas and all supercritical solutions for SF6 densities ³ r * = 0.3, and increases with SF6 density. 2DIR spectral analysis offers direct time domain evidence of critical slowing for SF6 solutions closest to the critical point density. Applications of 2DIR to other high density and supercritical solution dynamics and descriptions are discussed. <br>

scholarly journals Theory of Thermodynamic Variables of Rubber Band Heat Engine

2016 ◽  
Vol 739 ◽  
pp. 012091 ◽  
Author(s):  
Nurhidayah Muharayu ◽  
Widayani ◽  
Khairurrijal
Keyword(s):  
Heat Engine ◽  
Rubber Band ◽  
Thermodynamic Variables

A Tool for Thermoeconomic Analysis and Optimization of Gas, Steam, and Combined Plants

1997 ◽  
Vol 119 (4) ◽  
pp. 885-892 ◽  
Author(s):  
A. Agazzani ◽  
A. F. Massardo
Keyword(s):  
Cost Model ◽  
Optimization Technique ◽  
Energy System ◽  
Physical Structure ◽  
Capital Cost ◽  
Marginal Costs ◽  
Electricity Cost ◽  
Combined Cycles ◽  
Thermodynamic Variables ◽  
Definition Of

The aim of this work is to demonstrate the capability of an original “modular” simulator tool for the thermoeconomic analysis of thermal-energy systems. The approach employed is based on the Thermoeconomic Functional Analysis (T.F.A.), which, through definition of the “functional productive diagram” and the establishment of the capital cost function of each component, allows the marginal costs and the unit product costs, i.e., the “internal economy,” of the functional exergy flows to be obtained in correspondence to the optimum point. The optimum design of the system is obtained utilizing a traditional optimization technique, which includes both physical structure of the energy system described in terms of thermodynamic variables and cost model (capital cost of the components, maintenance and amortization factors, unit fuel cost, unit electricity cost, etc.). As an application example to show the practicability of the tool, the thermoeconomic analysis of various complex multipressure combined cycles (with or without steam reheating) is carried out. The results are analyzed and discussed in depth.

scholarly journals On the dynamics of some small structural motifs in rRNA upon ligand binding

2008 ◽  
Vol 73 (1) ◽  
pp. 41-53
Author(s):  
Aleksandra Rakic ◽  
Petar Mitrasinovic
Keyword(s):  
Molecular Dynamics ◽  
Conformational Changes ◽  
Binding Sites ◽  
De Novo ◽  
Reference Structure ◽  
Base Pairs ◽  
Rna Sequences ◽  
Conformational Model ◽  
Thermodynamic Variables ◽  
Dynamics Simulations

The present study characterizes using molecular dynamics simulations the behavior of the GAA (1186-1188) hairpin triloops with their closing c-g base pairs in large ribonucleoligand complexes (PDB IDs: 1njn, 1nwy, 1jzx). The relative energies of the motifs in the complexes with respect to that in the reference structure (unbound form of rRNA; PDB ID: 1njp) display the trends that agree with those of the conformational parameters reported in a previous study1 utilizing the de novo pseudotorsional (?,?) approach. The RNA regions around the actual RNA-ligand contacts, which experience the most substantial conformational changes upon formation of the complexes were identified. The thermodynamic parameters, based on a two-state conformational model of RNA sequences containing 15, 21 and 27 nucleotides in the immediate vicinity of the particular binding sites, were evaluated. From a more structural standpoint, the strain of a triloop, being far from the specific contacts and interacting primarily with other parts of the ribosome, was established as a structural feature which conforms to the trend of the average values of the thermodynamic variables corresponding to the three motifs defined by the 15-, 21- and 27-nucleotide sequences. From a more functional standpoint, RNA-ligand recognition is suggested to be presumably dictated by the types of ligands in the complexes.

Kinetics and mechanism of oxidative decomposition of Congo red by Fenton’s reagent and its synergic effects on exposure to UV radiation

2021 ◽  
Vol 25 (7) ◽  
pp. 8-12
Author(s):  
P. Rajendran ◽  
K. Geethu ◽  
P. Bashpa ◽  
K. Bijudas
Keyword(s):  
Congo Red ◽  
Homogeneous Medium ◽  
Ultra Violet ◽  
Kinetics And Mechanism ◽  
Fenton’S Reagent ◽  
Fenton Reagent ◽  
Fenton's Reagent ◽  
Oxidative Decomposition ◽  
Ultra Violet Radiation ◽  
Thermodynamic Variables

Congo red is a toxic azo dye which is used extensively in industries like textile, paper, pulp and paper. Very high amount of Congo red from these industrial sources is discharged into natural water bodies resulting environmental pollution. The present work reports the kinetics and mechanism of oxidative decomposition of Congo red by Fenton’s reagent in homogeneous medium and also under ultra violet light irradiation. Kinetic parameters like effect of [Fe2+], [H2O2], [Congo red] and temperature on the decomposition of Congo red were studied. The reaction is found to be fractional order with [Fe2+] and first order with [H2O2] and [Congo red]. The rate of oxidative decomposition of Congo red by Fenton’ reagent showed a rapid increase of three times when irradiated with ultra violet radiation and completion of reaction occurred within 5-6 minute. Various thermodynamic variables were determined and the presence of isosbestic points on sequential scanning of oxidation kinetics proves that the reaction is very smooth, spontaneous and endothermic. A suitable mechanism is suggested based on the experimental results obtained.

Symmetrization of interface dynamics equations

1992 ◽  
Vol 3 (3) ◽  
pp. 283-297 ◽  
Author(s):  
Leonid K. Antanovskii
Keyword(s):  
Chemical Potential ◽  
General Procedure ◽  
Unsteady Motion ◽  
Free Boundaries ◽  
Piecewise Constant ◽  
Mass Transfer Processes ◽  
Construction Of Self ◽  
Thermodynamic Variables ◽  
Capillary Fluid ◽  
Similar Solutions

The system of conservation laws governing heat and mass transfer processes in a continuous medium is obtained in a symmetric form on the basis of the successive application of fundamental thermodynamic principles. This approach involves reformulating the problem in intensive thermodynamic variables such as the temperature and chemical potential. The equations of capillary fluid mechanics and phase transitions with moving free boundaries are analysed in detail. The unsteady motion of a drop driven by buoyancy forces in an unbounded ambient fluid with dilute surfactants is investigated where the LeChatelier principle is established for an arbitrary surfactant. The general procedure for construction of self-similar solutions for the thermodiffusive Stefan problem with piecewise constant matrices of coefficients is described

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