scholarly journals Isotope effects on the high pressure viscosity of liquid water measured by differential dynamic microscopy

2020 ◽  
Vol 116 (23) ◽  
pp. 233701
Author(s):  
Mungo Frost ◽  
Siegfried H. Glenzer
Keyword(s):  
High Pressure ◽  
Liquid Water ◽  
Isotope Effects

Temperature, pressure, and isotope effects on the structure and properties of liquid water: A lattice approach

2007 ◽  
Vol 127 (22) ◽  
pp. 224106 ◽  
Author(s):  
Ilhem F. Hakem ◽  
Abdelhak Boussaid ◽  
Hafida Benchouk-Taleb ◽  
Michael R. Bockstaller
Keyword(s):  
Liquid Water ◽  
Isotope Effects ◽  
Structure And Properties ◽  
Lattice Approach

Translational and Rotational Diffusion in Liquid Water at Very High Pressure: A Simulation Study

2019 ◽  
Vol 123 (47) ◽  
pp. 10025-10035 ◽  
Author(s):  
Pascale Friant-Michel ◽  
Jean-François Wax ◽  
Nadège Meyer ◽  
Hong Xu ◽  
Claude Millot
Keyword(s):  
High Pressure ◽  
Simulation Study ◽  
Liquid Water ◽  
Rotational Diffusion ◽  
Translational And Rotational Diffusion ◽  
Very High

scholarly journals Phase transitions and critical phenomena of ice under high pressure

2014 ◽  
Vol 70 (a1) ◽  
pp. C894-C894
Author(s):  
Masakazu Matsumoto ◽  
Kazuhiro Himoto ◽  
Kenji Mochizuki ◽  
Hideki Tanaka
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Phase Transitions ◽  
Phase Boundary ◽  
Liquid Water ◽  
Tricritical Point ◽  
Melting Curve ◽  
Md Simulations ◽  
Free Energy Calculations ◽  
Lattice Points

Water distributes ubiquitously among the solar system and outer space in a wide variety of solid forms, i.e. more than ten kinds of crystalline ice, two types of amorphous ice, and clathrate hydrates. These polymorphs often play crucial roles in the planetary geology. Diversity of the stable ices and hydrates also suggests the existence of the various kinds of stable and metastable phases yet to be discovered [1]. Computer simulations and the theoretical treatments are useful to explore them. In this talk, we introduce the phase transitions of ice VII, which is one of the highest-pressure ice phases. The melting curve of ice VII to high-pressure liquid water has not been settled by experiments. We have proposed the intervention of a plastic phase of ice (plastic ice) between ice VII and liquid water, based on molecular dynamics (MD) simulations and the free energy calculations [2], which enables to account for large gaps among the various experimental curves of ice VII. In plastic ice, the water molecules are fixed at the lattice points, while they rotate freely. Interestingly, our additional survey by large-scale MD simulations elucidates that the phase transition between ice VII and plastic ice is first-order at low pressure as it was already predicted, while it is found to be second-order at higher pressures, where a tricritical point joins these phase boundaries together [3]. The critical fluctuations may give a clue for determining the phase boundary experimentally. We also argue about the phase transition dynamics of liquid water to ice VII at their direct phase boundary where metastable plastic ice phase plays an important role.

Liquid Water-Ice I Phase Diagrams under High Pressure: Sodium Chloride and Sucrose Models for Food Systems

2008 ◽  
Vol 21 (2) ◽  
pp. 439-445 ◽  
Author(s):  
Bérengère Guignon ◽  
Laura Otero ◽  
Antonio D. Molina-García ◽  
Pedro D. Sanz
Keyword(s):  
High Pressure ◽  
Sodium Chloride ◽  
Phase Diagrams ◽  
Liquid Water ◽  
Food Systems ◽  
Water Ice

scholarly journals Unusual origins of isotope effects in enzyme-catalysed reactions

2006 ◽  
Vol 361 (1472) ◽  
pp. 1341-1349 ◽  
Author(s):  
Dexter B Northrop
Keyword(s):  
High Pressure ◽  
Isotope Effects ◽  
Heavy Atom ◽  
Zero Point ◽  
Protein Domain ◽  
Enzymatic Reactions ◽  
Volume Changes ◽  
Mass Unit ◽  
Deuterium Isotope Effects ◽  
Domain Motions

High hydrostatic pressure is a neglected tool for probing the origins of isotope effects. In chemical reactions, normal primary deuterium isotope effects (DIEs) arising solely from differences in zero point energies are unaffected by pressure; but some anomalous isotope effects in which hydrogen tunnelling is suspected are partially suppressed. In some enzymatic reactions, high pressure completely suppresses the DIE. We have now measured the effects of high pressure on the parallel 13 C heavy atom isotope effect of yeast alcohol dehydrogenase and found that it is also suppressed by high pressure and, similarly, suppressed in its entirety. Moreover, the volume changes associated with the suppression of both deuterium and heavy atom isotope effects are virtually identical. The equivalent decrease in activation volumes for hydride transfer, when one mass unit is added to the carbon end of a scissile C–H bond as when one mass unit is added to the hydrogen end, suggests a common origin. Given that carbon is highly unlikely to undergo tunnelling, it follows that hydrogen is not doing so either. The origin of these isotope effects must lie elsewhere. We offer protein domain motions as a possibility.

A 19-Month Record of Marine Aerosol–Cloud–Radiation Properties Derived from DOE ARM Mobile Facility Deployment at the Azores. Part I: Cloud Fraction and Single-Layered MBL Cloud Properties

2014 ◽  
Vol 27 (10) ◽  
pp. 3665-3682 ◽  
Author(s):  
Xiquan Dong ◽  
Baike Xi ◽  
Aaron Kennedy ◽  
Patrick Minnis ◽  
Robert Wood
Keyword(s):  
Boundary Layer ◽  
High Pressure ◽  
Liquid Water ◽  
Mixed Boundary ◽  
Cloud Condensation Nuclei ◽  
Low Pressure ◽  
Cloud Fraction ◽  
Cloud Base ◽  
Microphysical Properties ◽  
Cloud Properties

Abstract A 19-month record of total and single-layered low (<3 km), middle (3–6 km), and high (>6 km) cloud fractions (CFs) and the single-layered marine boundary layer (MBL) cloud macrophysical and microphysical properties was generated from ground-based measurements at the Atmospheric Radiation Measurement Program (ARM) Azores site between June 2009 and December 2010. This is the most comprehensive dataset of marine cloud fraction and MBL cloud properties. The annual means of total CF and single-layered low, middle, and high CFs derived from ARM radar and lidar observations are 0.702, 0.271, 0.01, and 0.106, respectively. Greater total and single-layered high (>6 km) CFs occurred during the winter, whereas single-layered low (<3 km) CFs were more prominent during summer. Diurnal cycles for both total and low CFs were stronger during summer than during winter. The CFs are bimodally distributed in the vertical with a lower peak at ~1 km and a higher peak between 8 and 11 km during all seasons, except summer when only the low peak occurs. Persistent high pressure and dry conditions produce more single-layered MBL clouds and fewer total clouds during summer, whereas the low pressure and moist air masses during winter generate more total and multilayered clouds, and deep frontal clouds associated with midlatitude cyclones. The seasonal variations of cloud heights and thickness are also associated with the seasonal synoptic patterns. The MBL cloud layer is low, warm, and thin with large liquid water path (LWP) and liquid water content (LWC) during summer, whereas during winter it is higher, colder, and thicker with reduced LWP and LWC. The cloud LWP and LWC values are greater at night than during daytime. The monthly mean daytime cloud droplet effective radius re values are nearly constant, while the daytime droplet number concentration Nd basically follows the LWC variation. There is a strong correlation between cloud condensation nuclei (CCN) concentration NCCN and Nd during January–May, probably due to the frequent low pressure systems because upward motion brings more surface CCN to cloud base (well-mixed boundary layer). During summer and autumn, the correlation between Nd and NCCN is not as strong as that during January–May because downward motion from high pressure systems is predominant. Compared to the compiled aircraft in situ measurements during the Atlantic Stratocumulus Transition Experiment (ASTEX), the cloud microphysical retrievals in this study agree well with historical aircraft data. Different air mass sources over the ARM Azores site have significant impacts on the cloud microphysical properties and surface CCN as demonstrated by great variability in NCCN and cloud microphysical properties during some months.

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