On: “Important design considerations for inboard airborne magnetic gradiometers” by C. D. Hardwick (GEOPHYSICS, 49, 2004–2018, November 1984).

Geophysics ◽  
1986 ◽  
Vol 51 (1) ◽  
pp. 192-193
Author(s):  
Peter Hood
Keyword(s):  
Measurement System ◽  
High Sensitivity ◽  
Vertical Gradient ◽  
Geological Survey ◽  
Total Field ◽  
Aeromagnetic Survey ◽  
Design Considerations ◽  
Line Spacing ◽  
Important Design ◽  
Airborne Magnetic

In the above paper, the author states that military‐type magnetic compensators such as the nine‐term compensator produced by Canadian Aviation Electrons (CAE) of Montreal, Quebec may not be suitable for aeromagnetic survey work. In view of his doubts, I wish to assure him that 14 years of usage by the Geological Survey of Canada (GSC) has demonstrated without question that the CAE compensator is efficient for high‐sensitivity aeromagnetic survey work. The GSC first installed a CAE compensator in 1969 on its light, twin‐engine Beechcraft Queenair aircraft, and since that time approximately 450 total field and vertical gradient maps have been produced. Because the device is used for surveys in which the line spacing is commonly 300 m and has been as low as 150 m, any substantial deficiencies in the measurement system would have been readily apparent in the resultant contoured data. These would show as one‐line isolated anomalies and otherwise abnormal contour patterns, etc. Indeed, such effects would be particularly noticeable in the vertical gradient data because the contour interval used in the published maps is only 0.025 γ/m.

The aeromagnetic survey program of the Geological Survey of Canada: contribution to regional geological mapping and mineral exploration

1993 ◽  
Vol 30 (2) ◽  
pp. 243-260 ◽  
Author(s):  
D. J. Teskey ◽  
P. J. Hood ◽  
L. W. Morley ◽  
R. A. Gibb ◽  
P. Sawatzky ◽  
...  
Keyword(s):  
Mineral Exploration ◽  
National Research Council ◽  
High Sensitivity ◽  
Geological Mapping ◽  
Geological Survey ◽  
The Arctic ◽  
Navigation Systems ◽  
Current Standard ◽  
Private Industry ◽  
Aeromagnetic Survey

The aeromagnetic survey operations of the Geological Survey of Canada (GSC) began in 1946, utilizing a magnetometer in a bird system towed by a Royal Canadian Air Force Anson. Subsequent early operations were carried out by the GSC-operated Canso and Aero Commander aircraft. In 1961, the GSC in-house survey team formed the nucleus of a contract surveys group set up to monitor a new program established to complete the aeromagnetic mapping of the Canadian Shield in 12 years on a cost-sharing basis with the provinces. Today, surveys are carried out under contract by light twin-engine aircraft such as the Cessna 404 and even, in some cases, single-engine aircraft that utilize compact computer-controlled data acquisition and navigation systems and inboard magnetometer installations. Early systems were capable of resolution of only a few nanoteslas (nT) compared to the current standard of 0.1 nT or less, and flight path positioning with 35 mm film and photomosaics or topographical maps was extremely challenging. Despite these limitations, the careful selection of survey parameters and attention given to quality control have resulted in a world-class aeromagnetic data base that has contributed significantly to regional geological mapping and to mineral and oil exploration in Canada. Concurrently, the GSC carried out research programs into the development of instrumentation and into processing, interpretation, and enhancement techniques. In 1968, the GSC acquired its own platform, a Beechcraft B80 Queenair, which was used to develop high-sensitivity techniques, and an inboard gradiometer system, which was transferred to private industry in 1983. The GSC, in cooperation with the Flight Research Laboratory of the National Research Council of Canada, has also conducted a program of research into magnetometry and navigation combined with aeromagnetic studies of the Arctic since 1962.

scholarly journals Greenland ice cap aeromagnetic survey 1983: acquisition of high sensitivity total field and gradient magnetic data

1984 ◽  
Vol 120 ◽  
pp. 32-36
Author(s):  
L Thorning ◽  
M Bower ◽  
C.D Hardwick ◽  
P.J Hood
Keyword(s):  
High Sensitivity ◽  
Field Work ◽  
Magnetic Data ◽  
Total Field ◽  
Aeromagnetic Survey ◽  
East Greenland ◽  
Preliminary Results ◽  
Ice Cap ◽  
Geological Boundaries ◽  
First Time

A new high sensitivity aeromagnetic survey covering approximately 145 000 km2 of the lnland Ice (fig. 14) has been carried out during two periods of field operations in AprilIMay and September 1983. It is the first time a systematic, high sensitivity aeromagnetic coverage over the Greenland lnland Ice has been achieved. This note briefly reports on the background of the project, the fieId operations, and the preliminary results. Previous aeromagnetic surveys of ice-free regions of central and southern West Greenland (Thorning, 1976, 1977, and in prep.) have shown that many major geological boundaries are clearly reflected in the aeromagnetie data acquired over these regions. Geological field work in south-east Greenland has revealed the existence of similar geological boundaries, but their assumed position under the lnland lce has so far been guesswork. The aeromagnetic survey reported here is intended to provide real information on regional struetures under the lnland lce between the two coastal areas.

DESIGN OF SPATIAL FILTERS AND THEIR APPLICATION TO HIGH‐RESOLUTION AEROMAGNETIC DATA

Geophysics ◽  
1972 ◽  
Vol 37 (1) ◽  
pp. 68-91 ◽  
Author(s):  
B. K. Bhattacharyya
Keyword(s):  
High Resolution ◽  
Field Data ◽  
Vertical Gradient ◽  
Double Fourier Series ◽  
Two Dimensional ◽  
Total Field ◽  
Spatial Filters ◽  
Aeromagnetic Survey ◽  
Potential Field Data ◽  
High Frequency Response

Methods for the design of spatial filters are discussed in this paper. For a given response of a one‐dimensional filter, the weighting coefficients are calculated by solving a set of simultaneous equations with a simple matrix inversion procedure. In the case of a two‐dimensional filter, the method for obtaining the coefficients of a double Fourier series representing a set of given values is used to design the spatial operator. The problems connected with the length of the operator and the choice of a suitable decay in the high‐frequency response are discussed in detail. In order to show the usefulness of these methods, the paper presents several examples of operators designed for computing the vertical gradient, the second vertical derivative, and downward continuation of potential field data. A two‐dimensional vertical gradient filter is applied to the total field data obtained during a high‐resolution aeromagnetic survey over an area in the Precambrian Shield of Northeastern Ontario. The calculated gradient maps are compared with maps showing measured gradient values. The quality of the calculated maps in defining trends, patterns, and detailed features of anomalies shows the feasibility of obtaining very accurate vertical gradient maps from observed total field data.

Aeromagnetic survey in southern West Greenland: project Aeromag 1999

2000 ◽  
pp. 73-77 ◽  
Author(s):  
Thorkild M. Rasmussen ◽  
Jeroen A.M. Van Gool
Keyword(s):  
European Union ◽  
Measured Data ◽  
Geophysical Data ◽  
Geological Survey ◽  
Aeromagnetic Survey ◽  
Original Series ◽  
West Greenland ◽  
The Government ◽  
Airborne Geophysical Data ◽  
Surface Geology

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Rasmussen, T. M., & van Gool, J. A. (2000). Aeromagnetic survey in southern West Greenland: project Aeromag 1999. Geology of Greenland Survey Bulletin, 186, 73-77. https://doi.org/10.34194/ggub.v186.5218 _______________ The acquisition of public airborne geophysical data from Greenland that commenced in 1992 continued in 1999 with project Aeromag 1999, an aeromagnetic survey of part of southern West Greenland. This paper presents results of the aeromagnetic survey and discusses the correlation of the measured data with the previously mapped surface geology. The project was financed by the Government of Greenland and managed by the Geological Survey of Denmark and Greenland. Sander Geophysics Ltd., Ottawa, Canada, was selected in April 1999 as the contractor for the project through a European Union opentender procedure.

scholarly journals Aeromagnetic survey in Kusatsu-Shirane volcano, central Japan, by using an unmanned helicopter

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Takao Koyama ◽  
Wataru Kanda ◽  
Mitsuru Utsugi ◽  
Takayuki Kaneko ◽  
Takao Ohminato ◽  
...  
Keyword(s):  
Hydrothermal Systems ◽  
Magnetic Data ◽  
Unmanned Helicopter ◽  
Quaternary Period ◽  
Aeromagnetic Survey ◽  
Magnetization Intensity ◽  
Line Spacing ◽  
Normal Polarity ◽  
The Cost ◽  
Measurement Line

AbstractKusatsu-Shirane volcano is one of the active volcanoes in Japan. Phreatic explosions occurred in Mt. Shirane in 1983 and most recently, in 2018, in Mt. Motoshirane. Information on the subsurface structure is crucial for understanding the activity of volcanoes with well-developed hydrothermal systems where phreatic eruptions occur. Here, we report aeromagnetic surveys conducted at low altitudes using an unmanned helicopter. The survey aimed to obtain magnetic data at a high spatial resolution to map the magnetic anomaly and infer the magnetization intensity distribution in the region immediately after the 2018 Mt. Motoshirane eruption. The helicopter used in the survey was YAMAHA FAZER R G2, an autonomously driven model which can fly along a precisely programmed course. The flight height above the ground and a measurement line spacing were set to ~ 150 m and ~ 100 m, respectively, and the total flight distance was 191 km. The measured geomagnetic total intensity was found to vary by ~ 1000 nT peak-to-peak. The estimated magnetization intensity derived from measured data showed a 100 m thick magnetized surface layer with normal polarity, composed of volcanic deposits of recent activities. Underneath, a reverse-polarity magnetization was found, probably corresponding to the Takai lava flow in the Early Quaternary period (~ 1 Ma) mapped in the region. Our results demonstrate the cost-effectiveness and accuracy of using drone magnetometers for mapping the rugged terrain of volcanoes.

scholarly journals Perceived Facilitators and Barriers to Engaging with a Digital Intervention among Those with Food Insecurity, Binge Eating, and Obesity

Nutrients ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 2458
Author(s):  
Anu Venkatesh ◽  
Angela Chang ◽  
Emilie A. Green ◽  
Tianna Randall ◽  
Raquel Gallagher ◽  
...  
Keyword(s):  
Binge Eating ◽  
Food Insecurity ◽  
Future Research ◽  
Grocery Stores ◽  
User Centered Design ◽  
Design Considerations ◽  
Digital Intervention ◽  
Intervention Cost ◽  
Facilitators And Barriers ◽  
Important Design

Interventions that address binge eating and food insecurity are needed. Engaging people with lived experience to understand their needs and preferences could yield important design considerations for such interventions. In this study, people with food insecurity, recurrent binge eating, and obesity completed an interview-based needs assessment to learn facilitators and barriers that they perceive would impact their engagement with a digital intervention for managing binge eating and weight. Twenty adults completed semi-structured interviews. Responses were analyzed using thematic analysis. Three themes emerged. Participants shared considerations that impact their ability to access the intervention (e.g., cost of intervention, cost of technology, accessibility across devices), ability to complete intervention recommendations (e.g., affordable healthy meals, education to help stretch groceries, food vouchers, rides to grocery stores, personalized to budget), and preferred intervention features for education, self-monitoring, personalization, support, and motivation/rewards. Engaging people with lived experiences via user-centered design methods revealed important design considerations for a digital intervention to meet this population’s needs. Future research is needed to test whether a digital intervention that incorporates these recommendations is engaging and effective for people with binge eating and food insecurity. Findings may have relevance to designing digital interventions for other health problems as well.

scholarly journals Fluid–Structure Coupling Effects in a Dual U-Tube Coriolis Mass Flow Meter

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 982
Author(s):  
Yuh-Chung Hu ◽  
Zen-Yu Chen ◽  
Pei-Zen Chang
Keyword(s):  
Product Design ◽  
Dynamic Balance ◽  
Fluid Viscosity ◽  
Fluid Structure ◽  
Development Platform ◽  
Design Considerations ◽  
Manufacture Process ◽  
Coupling Dynamics ◽  
Comsol Simulation ◽  
Important Design

Coriolis mass flowmeters are highly customized products involving high-degree fluid-structure coupling dynamics and high-precision manufacture. The typical delay from from order to shipment is at least 4 months. This paper presents some important design considerations through simulation and experiments, so as to provide manufacturers with a more time-efficient product design and manufacture process. This paper aims at simulating the fluid-structure coupling dynamics of a dual U-tube Coriolis mass flowmeter through the COMSOL simulation package. The simulation results are experimentally validated using a dual U-tube CMF manufactured by Yokogawa Co., Ltd. in a TAF certified flow testing factory provided by FineTek Co., Ltd. Some important design considerations are drawn from simulation and experiment. The zero drift will occur when the dual U-tube structure is unbalanced and therefore the dynamic balance is very important in the manufacturing of dual U-tube CMF. The fluid viscosity can be determined from the driving current of the voice coil actuator or the pressure loss between the inlet and outlet of CMF. Finally, the authors develop a simulation application based on COMSOL’s development platform. Users can quickly evaluate their design through by using this application. The present application can significantly shorten product design and manufacturing time.

An Approximate Analysis of Foundation Stresses in Horizontal Pressure Vessels

1980 ◽  
Vol 102 (3) ◽  
pp. 555-557
Author(s):  
Krishna P. Singh ◽  
V. K. Luk
Keyword(s):  
Solution Procedure ◽  
Pressure Vessels ◽  
Approximate Analysis ◽  
Loading Conditions ◽  
Mechanical Loads ◽  
Design Considerations ◽  
Desirable Feature ◽  
Horizontal Pressure ◽  
Linear Manner ◽  
Important Design

Saddle supports of horizontally mounted pressure vessels, when subject to seismic and mechanical loads, interact with the foundation in a highly non-linear manner. The maximum foundation concrete pressure, and hold-down bolt stresses are important design considerations which often govern the vessel support geometry. A method is given herein to determine the foundation stresses due to arbitrary imposed loadings. The solution procedure lends itself easily to automated computation—a highly desirable feature—since most nuclear equipment has to be analyzed for a large number of loading conditions.

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