Sensing the Critical Point of High-Pressure Mixtures

2004 ◽  
Vol 43 (39) ◽  
pp. 5192-5195 ◽  
Author(s):  
Jie Ke ◽  
Robert M. Oag ◽  
P. J. King ◽  
Michael W. George ◽  
Martyn Poliakoff
Keyword(s):  
High Pressure ◽  
Critical Point

Electronic properties ofCeIn3under high pressure near the quantum critical point

2001 ◽  
Vol 65 (2) ◽  
Author(s):  
G. Knebel ◽  
D. Braithwaite ◽  
P. C. Canfield ◽  
G. Lapertot ◽  
J. Flouquet
Keyword(s):  
High Pressure ◽  
Critical Point ◽  
Electronic Properties ◽  
Quantum Critical Point ◽  
Quantum Critical

Titania aerogels with tailored nano and microstructure: comparison of lyophilization and supercritical drying

2017 ◽  
Vol 89 (4) ◽  
pp. 501-509 ◽  
Author(s):  
Jan Šubrt ◽  
Eva Pližingrová ◽  
Monika Palkovská ◽  
Jaroslav Boháček ◽  
Mariana Klementová ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
High Pressure ◽  
Phase Composition ◽  
Critical Point ◽  
Amorphous Material ◽  
Supercritical Drying ◽  
Porous Composite ◽  
Titanyl Sulfate ◽  
Critical Point Drying ◽  
Highly Porous

AbstractStructure and phase composition of titania aerogels can be substantially influenced simply by the process of drying their parent water colloid suspensions prepared by the reaction of hydrogen peroxide with suspension of precipitates obtained by neutralization of solution of titanyl sulfate with ammonia. Two methods of drying are compared: (1) lyophilization of fast frozen material immersed in liquid nitrogen, and (2) critical point drying using supercritical CO2 under high pressure. Both methods of drying lead to yellow titanium peroxide aerogels consisting of nanometer-sized blocks. While lyophilization leads to foils consisting of nano-sized crystalline nuclei of peroxo-polytitanic acid dispersed in predominantly amorphous material, the critical point drying provides rather bulk highly porous composite consisting of randomly oriented flat nanoparticles (5–10 nm) composed of crystalline anatase and amorphous peroxo-polytitanic acid.

Lead Staining by Ion Implantation

1976 ◽  
Vol 34 ◽  
pp. 320-321
Author(s):  
B. C. Dobbs
Keyword(s):  
High Pressure ◽  
Electron Microscope ◽  
Ion Implantation ◽  
Critical Point ◽  
Radiation Damage ◽  
Lead Ions ◽  
Microscope Examination ◽  
Electron Microscope Examination

Ion implantation has been effectively used as a stain for biological specimens prepared for electron microscope examination (1,2). We have used this method of staining on critical point dried T4 bacteriophage. The lead ions proved to be a non-specific stain. However, these ions are also highly susceptible to radiation damage (3,4). With precautions, the specimens may be tilted to the implanting beam so that the implanted ions provide an ultrafine uniform shadowing for the specimen. Also, tilting effectively increases the thickness of the support film.400 mesh copper grids were covered with a 120Å formvar film, then carbonized with 50Å of carbon to provide the specimen support. The bacteriophage were then critical point dried (5) by first replacing the specimen water with ethanol, the ethanol by Freon 113 and the Freon 113 by Freon 13 which was then dried in a high pressure container.

scholarly journals Search for tricritical point in KH2PO4 at high pressure. I. Static dielectric behavior near critical point at zero pressure

1977 ◽  
Vol 17 (1) ◽  
pp. 333-335 ◽  
Author(s):  
A. B. Western ◽  
A. G. Baker ◽  
R. J. Pollina ◽  
V. H. Schmidt
Keyword(s):  
High Pressure ◽  
Critical Point ◽  
Tricritical Point ◽  
Dielectric Behavior

scholarly journals Recent Experimental Efforts on High-Pressure Supercritical Injection for Liquid Rockets and Their Implications

2012 ◽  
Vol 2012 ◽  
pp. 1-31 ◽  
Author(s):  
Bruce Chehroudi
Keyword(s):  
High Pressure ◽  
Critical Point ◽  
Space Shuttle ◽  
Specific Impulse ◽  
Liquid Oxygen ◽  
Liquid Jets ◽  
Rocket Engines ◽  
Liquid Rocket Engines ◽  
Liquid Rocket ◽  
Air Force Research Laboratory

Pressure and temperature of the liquid rocket thrust chambers into which propellants are injected have been in an ascending trajectory to gain higher specific impulse. It is quite possible then that the thermodynamic condition into which liquid propellants are injected reaches or surpasses the critical point of one or more of the injected fluids. For example, in cryogenic hydrogen/oxygen liquid rocket engines, such as Space Shuttle Main Engine (SSME) or Vulcain (Ariane 5), the injected liquid oxygen finds itself in a supercritical condition. Very little detailed information was available on the behavior of liquid jets under such a harsh environment nearly two decades ago. The author had the opportunity to be intimately involved in the evolutionary understanding of injection processes at the Air Force Research Laboratory (AFRL), spanning sub- to supercritical conditions during this period. The information included here attempts to present a coherent summary of experimental achievements pertinent to liquid rockets, focusing only on the injection of nonreacting cryogenic liquids into a high-pressure environment surpassing the critical point of at least one of the propellants. Moreover, some implications of the results acquired under such an environment are offered in the context of the liquid rocket combustion instability problem.

Design and Test Plan of the Supercritical CO2 Compressor Test Loop

2008 ◽  
Author(s):  
Takao Ishizuka ◽  
Yasushi Muto ◽  
Masanori Aritomi
Keyword(s):  
High Pressure ◽  
Critical Point ◽  
Thermal Efficiency ◽  
Supercritical Co2 ◽  
Thermal Power ◽  
Low Pressure ◽  
Fiscal Year ◽  
Pressure Side ◽  
Test Loop ◽  
Pressure Compressor

Supercritical carbon dioxide (CO2) gas turbine systems can generate power at a high cycle thermal efficiency, even at modest temperatures of 500–550°C. That high thermal efficiency is attributed to a markedly reduced compressor work in the vicinity of critical point. In addition, the reaction between sodium (Na) and CO2 is milder than that between H2O and Na. Consequently, a more reliable and economically advantageous power generation system can be created by coupling with a Na-cooled fast breeder reactor. In a supercritical CO2 turbine system, a partial cooling cycle is employed to compensate a difference in heat capacity for the high-temperature — low-pressure side and low-temperature — high-pressure side of the recuperators to achieve high cycle thermal efficiency. In our previous work, a conceptual design of the system was produced for conditions of reactor thermal power of 600 MW, turbine inlet condition of 20 MPa/527°C, recuperators 1 and 2 effectiveness of 98%/95%, Intermediate Heat Exchanger (IHX) pressure loss of 8.65%, a turbine adiabatic efficiency of 93%, and a compressor adiabatic efficiency of 88%. Results revealed that high cycle thermal efficiency of 43% can be achieved. In this cycle, three different compressors, i.e., a low-pressure compressor, a high-pressure compressor, and a bypass compressor are included. In the compressor regime, the values of properties such as specific heat and density vary sharply and nonlinearly, dependent upon the pressure and temperature. Therefore, the influences of such property changes on compressor design should be clarified. To obtain experimental data for the compressor performance in the field near the critical point, a supercritical CO2 compressor test project was started at the Tokyo Institute of Technology on June 2007 with funding from MEXT, Japan. In this project, a small centrifugal CO2 compressor will be fabricated and tested. During fiscal year (FY) 2007, test loop components will be fabricated. During FY 2008, the test compressor will be fabricated and installed into the test loop. In FY 2009, tests will be conducted. This paper introduces the concept of a test loop and component designs for the cooler, heater, and control valves. A computer simulation program of static operation was developed based on detailed designs of components and a preliminary design of the compressor. The test operation regime is drawn for the test parameters.

Quantum critical point in ferromagnetic Kondo lattice CePt at high pressure

2004 ◽  
Vol 272-276 ◽  
pp. 54-55 ◽  
Author(s):  
J Larrea J ◽  
T Burghardt ◽  
A Eichler ◽  
M.B Fontes ◽  
A.D Alvarenga ◽  
...  
Keyword(s):  
High Pressure ◽  
Critical Point ◽  
Quantum Critical Point ◽  
Kondo Lattice ◽  
Quantum Critical
Sign in / Sign up

Export Citation Format

Share Document