scholarly journals In situ nuclear magnetic resonance response of permafrost and active layer soil in boreal and tundra ecosystems

2017 ◽  
Vol 11 (6) ◽  
pp. 2943-2955 ◽  
Author(s):  
M. Andy Kass ◽  
Trevor P. Irons ◽  
Burke J. Minsley ◽  
Neal J. Pastick ◽  
Dana R. N. Brown ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Active Layer ◽  
Liquid Water ◽  
Interdisciplinary Approach ◽  
Liquid Water Content ◽  
Soil Conditions ◽  
Near Surface ◽  
Nuclear Magnetic

Abstract. Characterization of permafrost, particularly warm and near-surface permafrost which can contain significant liquid water, is critical to understanding complex interrelationships with climate change, ecosystems, and disturbances such as wildfires. Understanding the vulnerability and resilience of permafrost requires an interdisciplinary approach, relying on (for example) geophysical investigations, ecological characterization, direct observations, remote sensing, and more. As part of a multiyear investigation into the impacts of wildfires on permafrost, we have collected in situ measurements of the nuclear magnetic resonance (NMR) response of the active layer and permafrost in a variety of soil conditions, types, and saturations. In this paper, we summarize the NMR data and present quantitative relationships between active layer and permafrost liquid water content and pore sizes and show the efficacy of borehole NMR (bNMR) to permafrost studies. Through statistical analyses and synthetic freezing simulations, we also demonstrate that borehole NMR is sensitive to the nucleation of ice within soil pore spaces.

scholarly journals <i>In situ</i> nuclear magnetic resonance response of permafrost and active layer soil in boreal and tundra ecosystems

2017 ◽  
Author(s):  
M. Andy Kass ◽  
Trevor P. Irons ◽  
Burke J. Minsley ◽  
Neal J. Pastick ◽  
Dana R. N. Brown ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Active Layer ◽  
Liquid Water ◽  
Interdisciplinary Approach ◽  
Liquid Water Content ◽  
Soil Conditions ◽  
Near Surface ◽  
Nuclear Magnetic

Abstract. Characterization of permafrost, particularly warm and near-surface permafrost which can contain significant liquid water, is critical to understanding complex interrelationships with climate change, ecosystems, and disturbances such as wildfires. Understanding the vulnerability and resilience of permafrost requires an interdisciplinary approach, relying on (for example) geophysical investigations, ecological characterization, direct observations, remote sensing, and more. As part of a multi-year investigation into the impacts of wildfires to permafrost, we have collected in situ measurements of the nuclear magnetic resonance (NMR) response of active layer and permafrost in a variety of soil conditions, types, and saturations. In this paper, we summarize the NMR data and present quantitative relationships between active layer and permafrost liquid water content and pore sizes. Through statistical analyses and synthetic freezing simulations, we also demonstrate that borehole NMR can image the nucleation of ice within soil pore spaces.

In situ enzymatic removal of orthophosphate by the nucleoside phosphorylase catalyzed phosphorolysis of nicotinamide riboside

1982 ◽  
Vol 60 (9) ◽  
pp. 917-921 ◽  
Author(s):  
John W. Shriver ◽  
Brian D. Sykes
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Nucleoside Phosphorylase ◽  
Nicotinamide Riboside ◽  
Time Required ◽  
Removal System ◽  
Nuclear Magnetic

An enzymatic orthophosphate removal system is described which can be effectively used to continuously remove orthophosphate from biochemical samples. The phosphorolysis of nicotinamide riboside is catalyzed by calf spleen nucleoside phosphorylase to give ribose-1-PO4 and nicotinamide along with a proton. At pH 8 the production of ribose-1-PO4 from orthophosphate is essentially quantitative. This reaction can be monitored optically or by 31P nuclear magnetic resonance (NMR). Equations are given for determining the time required to remove a given amount of phosphate from a typical NMR sample with a known amount of nucleoside phosphorylase. The effects of a competing orthophosphate-producing reaction are considered.

scholarly journals Nuclear Magnetic Resonance Spectroscopy for In Situ Monitoring of Porous Materials Formation under Hydrothermal Conditions

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1416 ◽  
Author(s):  
Mohamed Haouas
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Porous Materials ◽  
Local Environment ◽  
In Situ Monitoring ◽  
Resonance Spectroscopy ◽  
Hydrothermal Conditions ◽  
Technological Advances ◽  
Nuclear Magnetic

The employment of nuclear magnetic resonance (NMR) spectroscopy for studying crystalline porous materials formation is reviewed in the context of the development of in situ methodologies for the observation of the real synthesis medium, with the aim of unraveling the nucleation and growth processes mechanism. Both liquid and solid state NMR techniques are considered to probe the local environment at molecular level of the precursor species either soluble in the liquid phase or present in the reactive gel. Because the mass transport between the liquid and solid components of the heterogeneous system plays a key role in the synthesis course, the two methods provide unique insights and are complementary. Recent technological advances for hydrothermal conditions NMR are detailed and their applications to zeolite and related materials crystallization are illustrated. Achievements in the field are exemplified with some representative studies of relevance to zeolites, aluminophosphate zeotypes, and metal-organic frameworks.

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