Synchrotron X-Ray Radiation (CHESS) Study of Electric-Field Induced Changes in the Structure of Thermotropic Side-Chain Liquid Crystals

1993 ◽  
Vol 307 ◽  
Author(s):  
T. J. Bunning ◽  
S. G. McNamee ◽  
C. M. McHugh ◽  
S. S. Patnaik ◽  
C. K. Ober ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Electric Field ◽  
High Energy ◽  
Side Chain ◽  
Synchrotron Source ◽  
Correlation Lengths ◽  
Range Correlation ◽  
Induced Changes ◽  
Kinetics Of ◽  
Director Orientation

ABSTRACTSynchrotron radiation from the Cornell High Energy Synchrotron Source (CHESS) was used to probe the alignment kinetics of a class of thermotropic siloxane-based liquid crystals under the influence of an electric field. The high flux allows for real-time investigation of microstructural changes as a function of frequency and temperature. The packing behavior of a pentamethylcyclosiloxane ring with pendant biphenyl mesogens was thoroughly investigated. The director orientation parameter, Sd, typically increased with decreasing temperature and was not strongly affected by frequency. Electric-field induced changes in the director orientation were also monitored. Upon application of an electric field, the nematic system exhibited a tendency to pack in columns with short-range correlation of the mesogens. Column correlation lengths are examined as a function of temperature for two frequencies. At the low temperature end of the mesophase, a tendency for the mesogens to layer pack was observed.

Intelligent Gels

1999 ◽  
Vol 604 ◽  
Author(s):  
Yoshihito Osada ◽  
Jian Ping Gong ◽  
Tetsuharu Narita
Keyword(s):  
Electric Field ◽  
Shape Memory ◽  
Cationic Surfactant ◽  
Applied Electric Field ◽  
Molecular Assembly ◽  
Side Chain ◽  
Alkyl Side Chain ◽  
Thermodynamics And Kinetics ◽  
Kinetics Of ◽  
And Diffusion

AbstractWe reported an electro-driven chemomechanical hydrogel showing quick responses with worm-like motility. The principle of the motion is based on the molecular assembly reaction of cationic surfactant and negatively charged hydrogel. And direction of complexation accompanying gel contraction is controlled by changing the polarity of the applied electric field. Both thermodynamics and kinetics of surfactant binding and diffusion are investigated experimentally and theoretically. We also reported shape memory hydrogel by order-disorder transition of alkyl side chain, and some examples od friction of hydrogels showing that frictional behaviors of hydorgels do not conform to Amonton's law.

scholarly journals Magnetic-field-induced changes of the isotropic-nematic phase transition in side-chain polymer liquid crystals

2003 ◽  
Vol 67 (5) ◽  
Author(s):  
M. I. Boamfǎ ◽  
K. Viertler ◽  
A. Wewerka ◽  
F. Stelzer ◽  
P. C. M. Christianen ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Liquid Crystals ◽  
Nematic Phase ◽  
Side Chain ◽  
Chain Polymer ◽  
Polymer Liquid ◽  
Polymer Liquid Crystals ◽  
Induced Changes

scholarly journals ГОРІННЯ ПАЛИВА НА ОСНОВІ АЛКАНІВ ПІД ДІЄЮ ЕЛЕКТРИЧНОГО ПОЛЯ

2019 ◽  
pp. 39-48
Author(s):  
Світлана Геогіївна Орловська ◽  
Максим Сергійович Шкоропадо ◽  
Оксана Миколаївна Зуй
Keyword(s):  
Mass Transfer ◽  
Electric Field ◽  
Burning Rate ◽  
Heat And Mass Transfer ◽  
Liquid Fuel ◽  
Solid Phase ◽  
Combustion Process ◽  
Environmentally Friendly ◽  
High Energy ◽  
Kinetics Of

The relevance of research on the combustion processes of alkane-based fuels is due to the search for new, efficient, environmentally friendly fuels for the energy and aerospace industries. Paraffin (a mixture of alkanes) is a low-melting material that can be used as an environmentally friendly and high-energy fuel. An important task is to intensify the processes of fuel combustion in the reaction volume. One of the factors of intensification is the electric field. The purpose of this work is to study the laws of the influence of the electric field on the processes of high-temperature heat and mass transfer, melting and burning drops of liquid fuel based on alkanes.The paper developed a methodology for studying the kinetics of melting and burning of liquid fuel droplets using digital imaging of the object of study and computer processing of the images obtained.Studies have been conducted on the effect of a uniform electric field on the combustion of alkane particles in the air. The stages of heat and mass transfer in the combustion process are determined. It is shown that the melting of a particle is the main component of the induction period — the time during which the particle ignites. It was revealed that the melting rate significantly decreases if the electric field strength exceeds a certain critical value. It is established that the effect of the electric field on melting is more pronounced at high gas temperatures. It was found that when an octadecane particle melts in an electric field, the unmelted residual solid phase rotates in the melt. It is proved that this is a special case of the Quincke effect.The kinetics of combustion of octadecane drops of various initial diameters was studied. It has been proven that a linear law of variation of the square of the diameter of a droplet with time (Sreznevsky’s law) is fulfilled in a certain area of burning. The influence of the electric field on the burning rate of particles of different initial diameters was studied. It has been established that under the action of an electric field an increase in the rate of burning of alkane droplets occurs. In particular, for octadecane drops, the burning rate in a constant electric field increases by 10 ÷ 23% depending on the initial diameter of the drop. The burning rate constants of octadecane are found.The influence of the electric field on the geometric dimensions of the flame is studied. It is established that under the influence of the field the flame becomes asymmetrical and shifts towards the negatively charged plate of the capacitor. This reduces the height of the flame and increases its width. These phenomena are associated with the action of "ion wind" in the flame and the transformation of the energy of the electric field into heat. As a result of the action of these physical mechanisms, the combustion front approaches the surface of the drop, increasing its rate of evaporation.

Modeling the Effects of O-sulfonation on the CID of Serine

2020 ◽  
Author(s):  
Kenneth Lucas ◽  
George Barnes
Keyword(s):  
Sulfo Group ◽  
High Energy ◽  
Empirical Method ◽  
Side Chain ◽  
Energy Structure ◽  
Direct Dynamics ◽  
Theoretical Mass ◽  
Intermolecular Proton Transfer ◽  
Dynamics Simulations ◽  
Semi Empirical

We present the results of direct dynamics simulations and DFT calculations aimed at elucidating the effect of \textit{O}-sulfonation on the collision induced dissociation for serine. Towards this end, direct dynamics simulations of both serine and sulfoserine were performed at multiple collision energies and theoretical mass spectra obtained. Comparisons to experimental results are favorable for both systems. Peaks related to the sulfo group are identified and the reaction dynamics explored. In particular, three significant peaks (m\z 106, 88, and 81) seen in the theoretical mass spectrum directly related to the sulfo group are analyzed as well as major peaks shared by both systems. Our analysis shows that the m\z 106 peaks result from intramolecular rearrangements, intermolecular proton transfer among complexes composed of initial fragmentation products, and at high energy side-chain fragmentation. The \mz 88 peak was found to contain multiple constitutional isomers, including a previously unconsidered, low energy structure. It was also seen that the RM1 semi empirical method was not able to obtain all of the major peaks seen in experiment for sulfoserine. In contrast, PM6 did obtain all major experimental peaks.

scholarly journals Electrically driven formation and dynamics of Pac-Man solitons in smectic A liquid crystals

2021 ◽  
Author(s):  
Yuan Shen ◽  
Ingo Dierking
Keyword(s):  
Liquid Crystals ◽  
Electric Field ◽  
Spatiotemporal Chaos ◽  
Practical Applications ◽  
Smectic A ◽  
Fundamental Science ◽  
Smectic A Liquid Crystals

Electric field driven instabilities of liquid crystals, such as electro-convections, spatiotemporal chaos, backflows, and solitons are of great importance for both fundamental science and practical applications. Here we demonstrate that...

scholarly journals Accelerator design for the Cornell High Energy Synchrotron Source upgrade

2019 ◽  
Vol 22 (2) ◽  
Author(s):  
J. Shanks ◽  
J. Barley ◽  
S. Barrett ◽  
M. Billing ◽  
G. Codner ◽  
...  
Keyword(s):  
High Energy ◽  
Synchrotron Source ◽  
Accelerator Design
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