TERRAIN CORRECTIONS FOR BOREHOLE GRAVIMETRY

Geophysics ◽  
1968 ◽  
Vol 33 (2) ◽  
pp. 361-362 ◽  
Author(s):  
J. R. Hearst
Keyword(s):  
First Principles ◽  
Surface Density ◽  
Gravitational Constant ◽  
Terrain Correction ◽  
Correction Formula ◽  
Free Air ◽  
Terrain Corrections

The measurement of in‐situ density by borehole gravimetry has now become a commonly accepted, if not commonly used, practice (McCulloh, 1965, 1967; Howell et al., 1966; Hammer 1950). The expression for density as a function of gravity difference at two depths is given in a general form by McCulloh (1967) as [Formula: see text] [Formula: see text] where ρ is the density, F the free air gradient, [Formula: see text] the measured gravity difference between two depths, [Formula: see text] a correction for the effect of sub surface density differences (according to McCulloh, generally negligible), [Formula: see text] the terrain correction, [Formula: see text] a borehole correction, and k the gravitational constant. This equation can be obtained from first principles using Gauss’ law.

scholarly journals Metal-Free Air Oxidation in a Convenient Cascade Approach for the Access to Isoquinoline-1,3,4(2H)-triones

Molecules ◽  
2019 ◽  
Vol 24 (11) ◽  
pp. 2177
Author(s):  
Antonia Di Mola ◽  
Consiglia Tedesco ◽  
Antonio Massa
Keyword(s):  
Heterocyclic Compounds ◽  
Aromatic Ketone ◽  
Primary Amines ◽  
Cascade Process ◽  
Staudinger Reaction ◽  
Caspase Inhibitor ◽  
Air Oxidation ◽  
Metal Free ◽  
Free Air

Herein we describe a very useful application of the readily available trifunctional aromatic ketone methyl-2-(2-bromoacetyl)benzoate in reactions with primary amines. An unexpected in situ air oxidation that follows a cascade process allowed the access to a series of isoquinoline-1,3,4(2H)-triones, a class of heterocyclic compounds of great interest containing an oxygen-rich heterocyclic scaffold. A modification of the original protocol, utilizing a Staudinger reaction in the presence of trimethylphosphine, was necessary for the synthesis of Caspase inhibitor trione with free NH group.

scholarly journals Necessity of Terrain Correction in Magnetotelluric Data Recorded from Garhwal Himalayan Region, India

Geosciences ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 482
Author(s):  
Dharmendra Kumar ◽  
Arun Singh ◽  
Mohammad Israil
Keyword(s):  
Real Data ◽  
Terrain Correction ◽  
Himalayan Region ◽  
General Character ◽  
Period Range ◽  
Magnetotelluric Data ◽  
Heterogeneous Models ◽  
Corrected Data ◽  
Terrain Corrections ◽  
And Inversion

The magnetotelluric (MT) method is one of the useful geophysical techniques to investigate deep crustal structures. However, in hilly terrains, e.g., the Garhwal Himalayan region, due to the highly undulating topography, MT responses are distorted. Such responses, if not corrected, may lead to the incorrect interpretation of geoelectric structures. In the present paper, we implemented terrain corrections in MT data recorded from the Garhwal Himalayan Corridor (GHC). We used AP3DMT, a 3D MT data modeling and inversion code written in the MATLAB environment. Terrain corrections in the MT impedance responses for 39 sites along the Roorkee–Gangotri profile in the period range of 0.01 s to 1000 s were first estimated using a synthetic model by recording the topography and locations of MT sites. Based on this study, we established the general character of the terrain and established where terrain corrections were necessary. The distortion introduced by topography was computed for each site using homogenous and heterogeneous models with actual topographic variations. Period-dependent, galvanic and inductive distortions were observed at different sites. We further applied terrain corrections to the real data recorded from the GHC. The corrected data were inverted, and the inverted model was compared with the corresponding inverted model obtained with uncorrected data. The modification in electrical resistivity features in the model obtained from the terrain-corrected response suggests the necessity of terrain correction in MT data recorded from the Himalayan region.

scholarly journals Universality of sea wave growth and its physical roots

2015 ◽  
Vol 780 ◽  
pp. 503-535 ◽  
Author(s):  
Vladimir E. Zakharov ◽  
Sergei I. Badulin ◽  
Paul A. Hwang ◽  
Guillemette Caulliez
Keyword(s):  
First Principles ◽  
Physical Mechanism ◽  
Wave Interactions ◽  
Wave Modelling ◽  
Wave Development ◽  
The Impact ◽  
Nonlinear Wave Interactions ◽  
Sea Wave ◽  
Modelling And Forecasting

Assuming resonant nonlinear wave interactions to be the dominant physical mechanism of growing wind-driven seas we propose a concise relationship between instantaneous wave steepness and time or fetch of wave development expressed in dimensionless wave periods or lengths. This asymptotic physical law derived from the first principles of the theory of weak turbulence does not contain wind speed explicitly. The validity of this law is illustrated by results of numerical simulations, in situ measurements of growing wind seas and wind-wave tank observations. The impact of this new view of sea-wave physics is discussed in the context of conventional approaches to wave modelling and forecasting.

Catalyst-Free Conjugation and In Situ Quantification of Nanoparticle Ligand Surface Density Using Fluorogenic Cu-Free Click Chemistry

2011 ◽  
Vol 17 (12) ◽  
pp. 3326-3331 ◽  
Author(s):  
Rasmus I. Jølck ◽  
Honghao Sun ◽  
Rolf H. Berg ◽  
Thomas L. Andresen
Keyword(s):  
Click Chemistry ◽  
Surface Density ◽  
Catalyst Free

scholarly journals Using the conservative nature of fresh leaf surface density to measure foliar area

2014 ◽  
Vol 28 (4) ◽  
pp. 413-421
Author(s):  
Omar S. Castillo ◽  
Esther M. Zaragoza ◽  
Carlos J. Alvarado ◽  
Maria G. Barrera ◽  
Nabanita Dasgupta-Schubert
Keyword(s):  
Image Analysis ◽  
Leaf Area ◽  
Digital Image ◽  
Surface Density ◽  
Digital Image Analysis ◽  
Leaf Surface ◽  
Area Measurement ◽  
Fresh Leaf ◽  
The Masses

Abstract For a herbaceous species, the inverse of the fresh leaf surface density, the Hughes constant, is nearly conserved. We apply the Hughes constant to develop an absolute method of leafarea measurement that requires no regression fits, prior calibrations or oven-drying. The Hughes constant was determined in situ using a known geometry and weights of a sub-set obtained from the fresh leaves whose areas are desired. Subsequently, the leaf-areas (at any desired stratification level), were derived by utilizing the Hughes constant and the masses of the fresh leaves. The proof of concept was established for leaf-discs of the plants Mandevilla splendens and Spathiphyllum wallisii. The conservativeness of the Hughes constant over individual leaf-zones and different leaftypes from the leaves of each species was quantitatively validated. Using the globally averaged Hughes constant for each species, the leaf-area of these and additional co-species plants, were obtained. The leaf-area-measurement-by-mass was cross-checked with standard digital image analysis. There were no statistically significant differences between the leaf-area-measurement-by-mass and the digital image analysis measured leaf-areas and the linear correlation between the two methods was very good. Leaf-areameasurement- by-mass was found to be rapid and simple with accuracies comparable to the digital image analysis method. The greatly reduced cost of leaf-area-measurement-by-mass could be beneficial for small agri-businesses in developing countries.

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