Few years' experience with Automatic DIFlux systems: theory, validation and results

Mapping Intimacies ◽

10.5194/gi-2017-20 ◽

2017 ◽

Author(s):

Antoine Poncelet ◽

Alexandre Gonsette ◽

Jean Rasson

Keyword(s):

Systems Theory ◽

Magnetic Observatory ◽

Proof Of Concept ◽

The Absolute

Abstract. The previous release of our Automatic DIFlux, called AutoDIF mk2.2, is now running continuously since June 2012 in the absolute house of Dourbes magnetic observatory performing measurement every 30 minutes. A second one is working in the tunnel of Conrad observatory (Austria) since December 2013. After this proof of concept, we improved the AutoDIF to the version mk2.3 which was presented in 16th IAGA workshop in Hyderabad. Today, we have successfully deployed 6 AutoDIFs in various environments: 2 in Dourbes (DOU), 1 in Manhay (MAB), 1 in Conrad (CON), 1 in Deajeon (Korea) and 1 is used for tests. This one was installed for 10 month in Chambon-la-Foret (CLF) and since 2016 in Kakioka (KAK). In this paper, we will compare the automatic measurements with the human-made, and discuss the advantages/disadvantages of automatic measurements

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Several years of experience with automatic DI-flux systems: theory, validation and results

Geoscientific Instrumentation Methods and Data Systems ◽

10.5194/gi-6-353-2017 ◽

2017 ◽

Vol 6 (2) ◽

pp. 353-360 ◽

Cited By ~ 3

Author(s):

Antoine Poncelet ◽

Alexandre Gonsette ◽

Jean Rasson

Keyword(s):

South Korea ◽

Systems Theory ◽

Magnetic Observatory ◽

Years Of Experience ◽

Proof Of Concept ◽

Advantages And Disadvantages ◽

The Absolute

Abstract. The previous release of our automatic DI-flux instrument, called AutoDIF mk2.2, has now been running continuously since June 2012 in the absolute house of Dourbes magnetic observatory performing measurement every 30 min. A second one has been working in the tunnel of Conrad observatory (Austria) since December 2013. After this proof of concept, we improved the AutoDIF to version mk2.3, which was presented at the 16th IAGA workshop in Hyderabad. As of publication, we have successfully deployed six AutoDIFs in various environments: two in Dourbes (DOU), one in Manhay (MAB), one in Conrad (CON), one in Daejeon (South Korea) and one is used for tests. The latter was installed for 10 months in Chambon-la-Forêt (CLF) and, since 2016, has been in Kakioka (KAK). In this paper, we will compare the automatic to the human-made measurements and discuss the advantages and disadvantages of automatic measurements.

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USGS Experience with the Residual Absolutes Method

10.5194/gi-2017-24 ◽

2017 ◽

Cited By ~ 1

Author(s):

E. William Worthington ◽

Jurgen Matzka

Keyword(s):

High Latitude ◽

Baseline Data ◽

The Other ◽

Geological Survey ◽

Magnetic Observatory ◽

Residual Method ◽

Baseline Values ◽

The Absolute

Abstract. The U. S. Geological Survey (USGS) Geomagnetism Program has developed and tested the Residual Method of Absolutes, with the assistance of the Danish Technical University's (DTU) Geomagnetism Program. The computations of the absolute and baseline values are presented with improved calculations, such as the exact conversion from nanoTeslas (nT) to degrees. Three years of testing were performed at College Magnetic Observatory (CMO) to compare the Residual method with the Null method. Results show that the two methods compare very well with each other and both sets of baseline data were used to process the 2015 Definitive data. The Residual method is also being used at the Deadhorse Magnetic Observatory and will be implemented at the other USGS high latitude geomagnetic observatories in the summer of 2017.

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Contribution to solving the orientation problem for an automatic magnetic observatory

Geoscientific Instrumentation Methods and Data Systems ◽

10.5194/gi-2-1-2013 ◽

2013 ◽

Vol 2 (1) ◽

pp. 1-9 ◽

Cited By ~ 1

Author(s):

A. Khokhlov ◽

J. L. Le Mouël ◽

M. Mandea

Keyword(s):

Vertical Component ◽

Calibration Procedure ◽

High Accuracy ◽

Absolute Calibration ◽

Magnetic Observatory ◽

Time Interval ◽

Internal Calibration ◽

Scale Factors ◽

The Absolute ◽

Absolute Measurements

Abstract. The problem of the absolute calibration of a vectorial (tri-axial) magnetometer is addressed with the objective that the apparatus, once calibrated, gives afterwards, for a few years, the absolute values of the three components of the geomagnetic field (say the Northern geographical component, Eastern component and vertical component) with an accuracy on the order of 1 nT. The calibration procedure comes down to measure the orientation in space of the three physical axes of the sensor or, in other words, the entries of the transfer matrix from the local geographical axes to these physical axes. Absolute calibration follows indeed an internal calibration which provides accurate values of the three scale factors corresponding to the three axes – and in addition their relative angles. The absolute calibration can be achieved through classical absolute measurements made with an independent equipment. It is shown – after an error analysis which is not trivial – that, while it is not possible to get the axes absolute orientations with a high accuracy, the assigned objective (absolute values of the Northern geographical component, Eastern component and vertical component, with an accuracy of the order of 1 nT) is nevertheless reachable; this is because in the time interval of interest the field to measure is not far from the field prevailing during the calibration process.

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Solving the orientation problem for an automatic magnetic observatory

Geoscientific Instrumentation Methods and Data Systems Discussions ◽

10.5194/gid-2-337-2012 ◽

2012 ◽

Vol 2 (1) ◽

pp. 337-363

Author(s):

A. Khokhlov ◽

J. L. Le Mouël ◽

M. Mandea

Keyword(s):

Vertical Component ◽

Calibration Procedure ◽

High Accuracy ◽

Absolute Calibration ◽

Magnetic Observatory ◽

Time Interval ◽

Internal Calibration ◽

Scale Factors ◽

The Absolute ◽

Absolute Measurements

Abstract. The problem of the absolute calibration of a vectorial (tri-axial) magnetometer is addressed with the objective that the apparatus, once calibrated, gives afterwards, for a few years, the absolute values of the three components of the geomagnetic field (say the Northern geographical component, Eastern component and vertical component) with an accuracy of the order of 1 nT. The calibration procedure comes down to measure the orientation in space of the three physical axes of the sensor or, in other words, the entries of the transfer matrix from the local geographical axes to these physical axes. Absolute calibration follows indeed an internal calibration which provides accurate values of the three scale factors corresponding to the three axes – and in addition their relative angles. The absolute calibration can be achieved through classical absolute measurements made with an independent equipment. It is shown – after an error analysis which is not trivial – that, while it is not possible to get the axes absolute orientations with a high accuracy, the assigned objective (absolute values of the Northern geographical component, Eastern component and vertical component, with an accuracy of the order of 1 nT) is nevertheless reachable; this is because in the time interval of interest the field to measure are not far from the field prevailing during the calibration process.

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Homogenization of the historical series from the Coimbra Magnetic Observatory, Portugal

Earth System Science Data ◽

10.5194/essd-13-809-2021 ◽

2021 ◽

Vol 13 (2) ◽

pp. 809-825

Author(s):

Anna L. Morozova ◽

Paulo Ribeiro ◽

M. Alexandra Pais

Keyword(s):

20Th Century ◽

Geomagnetic Field ◽

Magnetic Observatory ◽

Time Interval ◽

Historical Series ◽

Long Lifetime ◽

The Absolute ◽

Nearly Continuous ◽

Continue Work ◽

Artificial Changes

Abstract. The Coimbra Magnetic Observatory (COI), Portugal, established in 1866, has provided nearly continuous records of the geomagnetic field elements for more than 150 years. However, during its long lifetime inevitable changes to the instruments and measurement procedures and even the relocation of the observatory have taken place. In our previous work (Morozova et al., 2014) we performed homogenization – elimination of the artificial changes – of the measured declination series (D) for the period from 1866 to 2006. In this paper we continue work on applying homogenization procedures to the measured series of the absolute monthly values of the horizontal (H, 1866–2006), vertical (Z, 1951–2006) and inclination components (I, 1866–1941). After homogenization of all measured series for the 1866–2006 time interval, we performed the homogenization of the series of all geomagnetic field elements (X, Y, Z, H, D, I and F) to the level of the 2015 epoch. Since all series except D have a gap of about 10 years in the middle of the 20th century, splitting each of them into two, the homogenization to the level of 2015 was done only for the series available after 1951 (with the D series homogenized for the whole time interval of 1866–2015). The COI geomagnetic field elements are available via the following addresses: https://doi.org/10.5281/zenodo.4308022 (Ribeiro et al., 2020) for the original COI data (ASCII and XLSX formats) and https://doi.org/10.5281/zenodo.4308036 (Morozova et al., 2020) for the homogenized COI data (ASCII and XLSX formats).

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Bulk standards for low-temperature biological x-ray microanalysis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100111525 ◽

1984 ◽

Vol 42 ◽

pp. 282-283

Author(s):

P. Echlin ◽

M. McKoon ◽

E.S. Taylor ◽

C.E. Thomas ◽

K.L. Maloney ◽

...

Keyword(s):

Phase Separation ◽

Low Temperature ◽

Analytical Method ◽

Salt Solutions ◽

Absolute Concentration ◽

Cooling Process ◽

X Ray ◽

The Absolute ◽

Analytical Procedures ◽

Electrical Conductors

Although sections of frozen salt solutions have been used as standards for x-ray microanalysis, such solutions are less useful when analysed in the bulk form. They are poor thermal and electrical conductors and severe phase separation occurs during the cooling process. Following a suggestion by Whitecross et al we have made up a series of salt solutions containing a small amount of graphite to improve the sample conductivity. In addition, we have incorporated a polymer to ensure the formation of microcrystalline ice and a consequent homogenity of salt dispersion within the frozen matrix. The mixtures have been used to standardize the analytical procedures applied to frozen hydrated bulk specimens based on the peak/background analytical method and to measure the absolute concentration of elements in developing roots.

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A Quantitative Ultrastructural Study of Peripheral Blood Lymphocytes Containing Parallel Tubular Arrays in Epstein-Barr Virus and Cytomegalo-Virus Mononucleosis

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100098769 ◽

1981 ◽

Vol 39 ◽

pp. 454-455

Author(s):

C. M. Payne ◽

P. M. Tennican

Keyword(s):

Peripheral Blood ◽

Lymphocyte Count ◽

Epstein Barr Virus ◽

Absolute Lymphocyte Count ◽

Peripheral Blood Lymphocytes ◽

Clinical State ◽

Barr Virus ◽

The Absolute ◽

Epstein Barr ◽

Tubular Arrays

In the normal peripheral circulation there exists a sub-population of lymphocytes which is ultrastructurally distinct. This lymphocyte is identified under the electron microscope by the presence of cytoplasmic microtubular-like inclusions called parallel tubular arrays (PTA) (Figure 1), and contains Fc-receptors for cytophilic antibody. In this study, lymphocytes containing PTA (PTA-lymphocytes) were quantitated from serial peripheral blood specimens obtained from two patients with Epstein -Barr Virus mononucleosis and two patients with cytomegalovirus mononucleosis. This data was then correlated with the clinical state of the patient.It was determined that both the percentage and absolute number of PTA- lymphocytes was highest during the acute phase of the illness. In follow-up specimens, three of the four patients' absolute lymphocyte count fell to within normal limits before the absolute PTA-lymphocyte count.In one patient who was followed for almost a year, the absolute PTA- lymphocyte count was consistently elevated (Figure 2). The estimation of absolute PTA-lymphocyte counts was determined to be valid after a morphometric analysis of the cellular areas occupied by PTA during the acute and convalescent phases of the disease revealed no statistical differences.

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Polarity Determination in Sphalerite and Wurtzite Structures

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100136106 ◽

1990 ◽

Vol 48 (2) ◽

pp. 500-501

Author(s):

Stuart McKernan ◽

C. Barry Carter

Keyword(s):

Opposite Polarity ◽

Single Domain ◽

Polar Material ◽

Electron Microscopic ◽

Dynamical Interaction ◽

X Ray ◽

Polarity Determination ◽

The Absolute ◽

Microscopic Techniques

The determination of the absolute polarity of a polar material is often crucial to the understanding of the defects which occur in such materials. Several methods exist by which this determination may be performed. In bulk, single-domain specimens, macroscopic techniques may be used, such as the different etching behavior, using the appropriate etchant, of surfaces with opposite polarity. X-ray measurements under conditions where Friedel’s law (which means that the intensity of reflections from planes of opposite polarity are indistinguishable) breaks down can also be used to determine the absolute polarity of bulk, single-domain specimens. On the microscopic scale, and particularly where antiphase boundaries (APBs), which separate regions of opposite polarity exist, electron microscopic techniques must be employed. Two techniques are commonly practised; the first [1], involves the dynamical interaction of hoLz lines which interfere constructively or destructively with the zero order reflection, depending on the crystal polarity. The crystal polarity can therefore be directly deduced from the relative intensity of these interactions.

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Direct measurement of electron-diffraction-pattern intensities using an energy loss spectrometer

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100155311 ◽

1989 ◽

Vol 47 ◽

pp. 668-669

Author(s):

A. G. Jackson ◽

M. Rowe

Keyword(s):

Thermal Effects ◽

Dynamic Range ◽

Scattering Amplitude ◽

Dynamical Theory ◽

Site Symmetry ◽

Proof Of Concept ◽

Parallel Acquisition ◽

Kinematic Approximation ◽

Speed Up ◽

Structure Calculations

Diffraction intensities from intermetallic compounds are, in the kinematic approximation, proportional to the scattering amplitude from the element doing the scattering. More detailed calculations have shown that site symmetry and occupation by various atom species also affects the intensity in a diffracted beam. [1] Hence, by measuring the intensities of beams, or their ratios, the occupancy can be estimated. Measurement of the intensity values also allows structure calculations to be made to determine the spatial distribution of the potentials doing the scattering. Thermal effects are also present as a background contribution. Inelastic effects such as loss or absorption/excitation complicate the intensity behavior, and dynamical theory is required to estimate the intensity value.The dynamic range of currents in diffracted beams can be 104or 105:1. Hence, detection of such information requires a means for collecting the intensity over a signal-to-noise range beyond that obtainable with a single film plate, which has a S/N of about 103:1. Although such a collection system is not available currently, a simple system consisting of instrumentation on an existing STEM can be used as a proof of concept which has a S/N of about 255:1, limited by the 8 bit pixel attributes used in the electronics. Use of 24 bit pixel attributes would easily allowthe desired noise range to be attained in the processing instrumentation. The S/N of the scintillator used by the photoelectron sensor is about 106 to 1, well beyond the S/N goal. The trade-off that must be made is the time for acquiring the signal, since the pattern can be obtained in seconds using film plates, compared to 10 to 20 minutes for a pattern to be acquired using the digital scan. Parallel acquisition would, of course, speed up this process immensely.

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