Studies of Critical Phenomena and Phase Transition with SANS and DKD in the Polymerblend PVME-PSD

1986 ◽  
Vol 79 ◽  
Author(s):  
D. Schwahn ◽  
K. Mortensen ◽  
H. Yee-Madeira
Keyword(s):  
Phase Transition ◽  
Polymer Blends ◽  
Critical Point ◽  
Critical Phenomena ◽  
Critical Behaviour ◽  
Transition Temperatures ◽  
Double Crystal ◽  
Dynamic Decomposition

AbstractCritical behaviour of PSD-PVME polymer blends are presented. Spinodal and binodal transition temperatures have been determined by the use of a SANS-camera, and non-meanfield characteristics have been observed close to the critical point. A dynamic decomposition study has been performed by the use of a neutron double crystal diffraction.

THE ISOSPIN DEPENDENCE OF THE NUCLEAR PHASE TRANSITION NEAR THE CRITICAL POINT

2010 ◽  
Vol 19 (08n09) ◽  
pp. 1570-1576
Author(s):  
Z. CHEN ◽  
R. WADA ◽  
A. BONASERA ◽  
T. KEUTGEN ◽  
K. HAGEL ◽  
...  
Keyword(s):  
Phase Transition ◽  
Molecular Dynamics ◽  
Free Energy ◽  
Phase Transitions ◽  
Critical Point ◽  
Critical Phenomena ◽  
Critical Points ◽  
Liquid Mixtures ◽  
Nuclear Phase ◽  
Isospin Dependence

The experimental results reveal the isospin dependence of the nuclear phase transition in terms of the Landau Free Energy description of critical phenomena. Near the critical point, different ratios of the neutron to proton concentrations lead to different critical points for the phase transition which is analogous to the phase transitions in He 4- He 3 liquid mixtures. The antisymmetrized molecular dynamics (AMD) and GEMINI models calculations were also performed and the results will be discussed as well.

Critical Scaling Behavior of Microemulsion Systems

1984 ◽  
Vol 24 (02) ◽  
pp. 197-202 ◽  
Author(s):  
John S. Huang ◽  
Mahn Won Kim
Keyword(s):  
Phase Transition ◽  
Phase Boundary ◽  
Critical Point ◽  
Critical Phenomena ◽  
Scaling Laws ◽  
Continuous System ◽  
Universal Function ◽  
Scaling Behavior ◽  
Critical Phase ◽  
Classical Thermodynamics

Abstract We used dynamic light scattering to study the characteristic droplet size, in dilute single-phase microemulsions near the critical phase transition point. We found that there existed a general power-law dependence of f on point. We found that there existed a general power-law dependence of f on the reduced variable = . Here stands for any thermodynamic and system variables whose critical value is denoted by . The variables of interest in the present work are temperature and alkane carbon number (ACN). It is found that where = . This is observed both in water- and oil-internal microemulsions, independent of the surfactant properties. This behavior, known as the scaling behavior, was analyzed in terms of generalized homogeneous functions with as the degree of homogeneity. It turns out that only one of the reduced variables is an independent variable in these functions, greatly simplifying the description of the properties of microemulsions in the neighborhood of a critical phase boundary. Introduction Critical phenomena have been under intensive investigation for the past 20 years by physicists and physical chemists. There are several reasons for this subject to attract so much attention. SINGULARITIES. A large number of thermodynamic properties, especially ones related to the second-order derivative of the free energy, become singular (in a mathematical sense) at the critical point. UNIVERSALITY. There exists a universal description (scaling laws) of the singular behavior of all the corresponding thermodynamic parameters in a large number of vastly different systems. These range from simple liquid/gas mixtures, liquid crystals, and magnetic alloys to the quantum mechanical superfluids. NONCLASSICAL BEHAVIOR. Though critical properties are macroscopic properties pertaining to the bulk phases, classical thermodynamics is properties pertaining to the bulk phases, classical thermodynamics is inadequate to explain quantitatively what happens in the neighborhood of the critical points. NEW PARAMETERS. Geometric properties (such as the symmetry group of the so-called "order parameter") and spatial dimensionality of the system are more important than the nature of basic interactions that produce the phase transition. phase transition. Great progress has been achieved, both experimentally (such as dynamic light scattering) and theoretically (such as the powerful scaling laws and renormalization group theories), in the study of critical phenomena. As a result, a vast amount of knowledge has been accumulated on the subject in recent years. Critical phenomena may also play an important role in the understanding of the fundamental mechanism in EOR by microemulsions and micellar solutions. Microemulsions do exhibit unmistakable critical behavior in certain composition and temperature ranges near the cloud point of a homogeneous system. There are many ways to cause a homogeneous microemulsion to split into a multiphase system. When any of the system variables, such as the temperature, salinity, composition of the oil, and concentration of the dispersed phase, are changed in such a manner that the resultant phase transition occurs in the neighborhood of a plait point, which corresponds to a vanishing tie line, then the system will exhibit critical phenomena. All critical transitions are characterized by pronounced thermodynamic fluctuations. These fluctuations are described by a con-elation length that diverges at the critical point, causing a strong scattering of light known as the critical opalescence, a feature that is also observed in microemulsions. By definition, the correlation length diverges at the critical value, Zc, of the corresponding system variable, . Therefore, the reduced variable delta Z = Zc -Z expresses a measure of a "thermodynamic distance" to the critical point. We use the lower-case letter z = delta Z/Zc to denote the dimensionless scaled variables that are important for the description of the universal behavior of a microemulsion near a critical phase boundary. In the neighborhood of the critical point, the physical phase boundary. In the neighborhood of the critical point, the physical properties of the microemulsion systems depend on some universal function properties of the microemulsion systems depend on some universal function of scaled variables only, independent of the chemical makeup of the system. We call this the critical scaling behavior. Experimental Procedure MICROEMULSION SYSTEM. We have chosen two model microemulsions for our study. One is a simple pure three-component oil-continuous system containing pure normal alkanes, distilled water, and a surfactant commonly known as AOT. This surfactant, sodium di-2-ethyl hexylsulfosuccinate, was twice recrystallized from hexane over activated charcoal. The other is a water-continuous system composed of 8% NaCl brine solution, normal alkanes and a combined surfactant (hepta-ethoxylated octadecyl methyl ammonium-i-dodecyl-o-xylene sulfonates). SPEJ p. 197

scholarly journals Solving the 2D SUSY Gross-Neveu-Yukawa model with conformal truncation

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
A. Liam Fitzpatrick ◽  
Emanuel Katz ◽  
Matthew T. Walters ◽  
Yuan Xin
Keyword(s):  
Phase Transition ◽  
Critical Point ◽  
Fine Tuning ◽  
Yukawa Model ◽  
Spectral Functions ◽  
Scalar Superfield ◽  
Local Operators ◽  
Dimensionless Coupling ◽  
Zumino Model ◽  
Yukawa Theory

Abstract We use Lightcone Conformal Truncation to analyze the RG flow of the two-dimensional supersymmetric Gross-Neveu-Yukawa theory, i.e. the theory of a real scalar superfield with a ℤ2-symmetric cubic superpotential, aka the 2d Wess-Zumino model. The theory depends on a single dimensionless coupling $$ \overline{g} $$ g ¯ , and is expected to have a critical point at a tuned value $$ {\overline{g}}_{\ast } $$ g ¯ ∗ where it flows in the IR to the Tricritical Ising Model (TIM); the theory spontaneously breaks the ℤ2 symmetry on one side of this phase transition, and breaks SUSY on the other side. We calculate the spectrum of energies as a function of $$ \overline{g} $$ g ¯ and see the gap close as the critical point is approached, and numerically read off the critical exponent ν in TIM. Beyond the critical point, the gap remains nearly zero, in agreement with the expectation of a massless Goldstino. We also study spectral functions of local operators on both sides of the phase transition and compare to analytic predictions where possible. In particular, we use the Zamolodchikov C-function to map the entire phase diagram of the theory. Crucial to this analysis is the fact that our truncation is able to preserve supersymmetry sufficiently to avoid any additional fine tuning.

scholarly journals Study of physical properties of a ferrimagnetic spinel Cu1.5Mn1.5O4: spin dynamics, magnetocaloric effect and critical behavior

RSC Advances ◽  
2021 ◽  
Vol 11 (41) ◽  
pp. 25664-25676
Author(s):  
Abir Hadded ◽  
Jalel Massoudi ◽  
Sirine Gharbi ◽  
Essebti Dhahri ◽  
A. Tozri ◽  
...  
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Physical Properties ◽  
Magnetocaloric Effect ◽  
Phase Transition Temperature ◽  
Magnetic Phase Transition ◽  
Critical Behavior ◽  
Magnetic Phase ◽  
Spin Dynamics ◽  
Critical Behaviour

The present work reports a detailed study of the spin dynamics, magnetocaloric effect and critical behaviour near the magnetic phase transition temperature, of a ferrimagnetic spinel Cu1.5Mn1.5O4.

scholarly journals Thermal, ferroelastic, and structural properties near phase transitions of organic–inorganic perovskite type [NH3(CH2)3NH3]CdBr4 crystals

RSC Advances ◽  
2021 ◽  
Vol 11 (29) ◽  
pp. 17622-17629
Author(s):  
Ae Ran Lim
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Thermal Behavior ◽  
Structural Properties ◽  
Structural Dynamics ◽  
Transition Temperatures ◽  
Inorganic Perovskite ◽  
Phase Transition Temperatures ◽  
Perovskite Type

We studied the thermal behavior and structural dynamics of [NH3(CH2)3NH3]CdBr4 near phase transition temperatures.

Triply-responsive OEG-based microgels and hydrogels: Regulation of swelling ratio, volume phase transition temperatures and mechanical properties

2021 ◽  
Author(s):  
Dongdong Lu ◽  
Mingning Zhu ◽  
Jing Jin ◽  
Brian R. Saunders
Keyword(s):  
Phase Transition ◽  
Biomedical Engineering ◽  
Volume Phase Transition ◽  
Swelling Ratio ◽  
Transition Temperatures ◽  
Ph Responsive ◽  
Network Systems ◽  
Volume Phase ◽  
Phase Transition Temperatures ◽  
Volume Swelling

Thermally- and pH-responsive microgels (MGs) and hydrogels are fascinating network systems that have been applied in biomedical engineering and sensing. The volume-swelling ratio (Q) and the volume-phase transition temperatures (VPTTs)...

scholarly journals Universality class of the motility-induced critical point in large scale off-lattice simulations of active particles.

Soft Matter ◽  
2021 ◽  
Author(s):  
Claudio Maggi ◽  
Matteo Paoluzzi ◽  
Andrea Crisanti ◽  
Emanuela Zaccarelli ◽  
Nicoletta Gnan
Keyword(s):  
Phase Separation ◽  
Critical Point ◽  
Computer Simulations ◽  
Large Scale ◽  
Universality Class ◽  
Critical Behaviour ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Active Particles ◽  
Two Dimensional Model

We perform large-scale computer simulations of an off-lattice two-dimensional model of active particles undergoing a motility-induced phase separation (MIPS) to investigate the systems critical behaviour close to the critical point...

scholarly journals Investigating phase transition temperatures of size separated gadolinium silicide magnetic nanoparticles

AIP Advances ◽  
2018 ◽  
Vol 8 (5) ◽  
pp. 056428 ◽  
Author(s):  
Shivakumar G. Hunagund ◽  
Shane M. Harstad ◽  
Ahmed A. El-Gendy ◽  
Shalabh Gupta ◽  
Vitalij K. Pecharsky ◽  
...  
Keyword(s):  
Phase Transition ◽  
Magnetic Nanoparticles ◽  
Transition Temperatures ◽  
Phase Transition Temperatures
Sign in / Sign up

Export Citation Format

Share Document