Design, fabrication and analysis of stagnation flow microreactors used to study hypergolic reactions

Lab on a Chip ◽  
2015 ◽  
Vol 15 (10) ◽  
pp. 2248-2257 ◽  
Author(s):  
Pulkit Saksena ◽  
Srinivas Tadigadapa ◽  
Richard A. Yetter
Keyword(s):  
Condensed Phase ◽  
Stagnation Flow ◽  
Novel Method ◽  
Condensed Phase Reactions ◽  
Hypergolic Propellants ◽  
Flow Microreactors

A novel method to study the condensed phase reactions that occur during the ignition of hypergolic propellants (very fast liquid reactions) using microreactors is presented.

Chemical Reactions In Condensed Phases

2006 ◽  
Author(s):  
Abraham Nitzan
Keyword(s):  
Chemical Reactions ◽  
Condensed Phase ◽  
Chemical Change ◽  
Classical Mechanics ◽  
Chemical System ◽  
Condensed Phases ◽  
Molecular Configuration ◽  
Middle Stage ◽  
Condensed Phase Reactions ◽  
Energy Surfaces

Understanding chemical reactions in condensed phases is essentially the understanding of solvent effects on chemical processes. Such effects appear in many ways. Some stem from equilibrium properties, for example, solvation energies and free energy surfaces. Others result from dynamical phenomena: solvent effect on diffusion of reactants toward each other, dynamical cage effects, solvent-induced energy accumulation and relaxation, and suppression of dynamical change in molecular configuration by solvent induced friction. In attempting to sort out these different effects it is useful to note that a chemical reaction proceeds by two principal dynamical processes that appear in three stages. In the first and last stages the reactants are brought together and products are separated from each other. In the middle stage the assembled chemical system undergoes the structural/chemical change. In a condensed phase the first and last stages involve diffusion, sometimes (e.g. when the species involved are charged) in a force field. The middle stage often involves the crossing of a potential barrier. When the barrier is high the latter process is rate-determining. In unimolecular reactions the species that undergoes the chemical change is already assembled and only the barrier crossing process is relevant. On the other hand, in bi-molecular reactions with low barrier (of order kBT or less), the rate may be dominated by the diffusion process that brings the reactants together. It is therefore meaningful to discuss these two ingredients of chemical rate processes separately. Most of the discussion in this chapter is based on a classical mechanics description of chemical reactions. Such classical pictures are relevant to many condensed phase reactions at and above room temperature and, as we shall see, can be generalized when needed to take into account the discrete nature of molecular states. In some situations quantum effects dominate and need to be treated explicitly. This is the case, for example, when tunneling is a rate determining process. Another important class is nonadiabatic reactions, where the rate determining process is hopping (curve crossing) between two electronic states. Such reactions are discussed in Chapter 16.

A Study of the Crossing Angle in Condensed-Phase CARS

1989 ◽  
Vol 43 (1) ◽  
pp. 61-65 ◽  
Author(s):  
Yukio Adachi ◽  
Chiaki Hirose
Keyword(s):  
Condensed Phase ◽  
Matching Condition ◽  
Laser Beams ◽  
Raman Shift ◽  
Phase Matching ◽  
Sample Cell ◽  
Normal Dispersion ◽  
Excitation Laser ◽  
Novel Method ◽  
Phase Matching Condition

A novel method of tuning the crossing angle, that is, the phase-matching condition, in condensed-phase CARS measurements has been presented. The method enables us to tune the phase-matching condition by simply tilting the sample cell with no need for adjusting the crossing angle of excitation laser beams over the range of about 600 cm−1.To this end, a relation between the crossing angle and the frequency difference between the two excitation lasers, which is associated with the Raman shift, has been derived in the normal dispersion region and has been experimentally examined.

The role of condensed-phase reactions in the burning of mixtures of fusible metals with ammonium perchlorate

1984 ◽  
Vol 20 (2) ◽  
pp. 161-163
Author(s):  
G. V. Ivanov ◽  
V. G. Surkov ◽  
L. N. Karmadonov ◽  
A. M. Viktorenko
Keyword(s):  
Ammonium Perchlorate ◽  
Condensed Phase ◽  
Condensed Phase Reactions

scholarly journals Precise control and measurement of solid–liquid interfacial temperature and viscosity using dual-beam femtosecond optical tweezers in the condensed phase

2016 ◽  
Vol 18 (37) ◽  
pp. 25823-25830 ◽  
Author(s):  
Dipankar Mondal ◽  
Paresh Mathur ◽  
Debabrata Goswami
Keyword(s):  
Optical Tweezers ◽  
Condensed Phase ◽  
Precise Control ◽  
Dual Beam ◽  
Novel Method ◽  
Interfacial Temperature ◽  
Solid Liquid Interface ◽  
Solid Liquid ◽  
And Control

We present a novel method of microrheology based on femtosecond optical tweezers, which in turn enables us to directly measure and controlin situtemperature at microscale volumes at the solid–liquid interface.

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