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Journal articles on the topic 'Magnetic measurements Data processing'

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Published: 10 December 2022
Last updated: 28 January 2023

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1

Khomutov, Sergey Y., and Manjula Lingala. "Some problems with old magnetic data processing." E3S Web of Conferences 196 (2020): 02029. http://dx.doi.org/10.1051/e3sconf/202019602029.

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Continues magnetic measurements at the IKIR FEB RAS obser-vatories Magadan (MGD), Paratunka (PET), Yuzhno-Sakhalinsk (YSS), Cape Schmidt (CPS) and Khabarovsk (KHB) and CSIR-NGRI observatories Hyder-abad (HYB) and Choutuppal (CPL) have been started almost since their formation. A significant part of the results obtained is presented in the WDC and INTERMAGNET databases. However, a large amount of raw data remains un-processed and unavailable for using by scientific community. In the past few years, institutes has been making efforts to process and reprocess old magnetic data. Digital images of analog magnetograms of the Observatory Paratunka since 1967 were obtained and the possibility of their use for calculation hourly and minute values of magnetic field elements was evaluated. Old digital data that was available during the conversion from analog to digital magnetometers is processed. The main problem of processing or re-processing archived data is the lack of information (metadata) about the measurement conditions. First of all, these are the results of absolute observations, which are necessary to obtain the values of the elements of the total field vector. In this paper, some technologies are proposed that allow to use the data obtained during processing of analog magnetograms to adjust the digital magnetometers records. A signif-icant problem is the lack or inaccuracy of information about the temperature conditions in the variation pavilion, about magnetometers or support equipment maintenance or about works in and near the pavilions. As we accumulate the experience during the processing of old magnetic data, a “catalog” of noise and its typical images is formed. This makes it more reliable and efficient to identify and remove this noise from records.
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2

Wang, R. F. "Data processing methods in the measurements of magnetic penetration depth." Physica C: Superconductivity 397, no. 1-2 (October 2003): 80–85. http://dx.doi.org/10.1016/s0921-4534(03)01092-x.

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3

Khomutov, Sergey Y., Oksana V. Mandrikova, Ekaterina A. Budilova, Kusumita Arora, and Lingala Manjula. "Noise in raw data from magnetic observatories." Geoscientific Instrumentation, Methods and Data Systems 6, no. 2 (September 15, 2017): 329–43. http://dx.doi.org/10.5194/gi-6-329-2017.

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Abstract. In spite of significant progress in the development of new devices for magnetic measurements, mathematical and computational technologies for data processing and means of communication, the quality of magnetic data accessible through the data centres (for example, World Data Centres or INTERMAGNET) still largely depends on the actual conditions in which observation of the Earth's magnetic field is performed at observatories. Processing of raw data of magnetic measurements by observatory staff plays an important role. It includes effective identification of noise and elimination of its influence on final data. In this paper, on the basis of the experience gained during long-term magnetic monitoring carried out at the observatories of IKIR FEB RAS (Russia) and CSIR-NGRI (India), we present a review of methods commonly encountered in actual practice for noise identification and the possibility of reducing noise influence.
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4

Gałach, H., M. J. Peryt, and N. Dunin. "Embedded Data Processing Using NI MyRIO and LabVIEW for Magnetic Field Measurements." Acta Physica Polonica B Proceedings Supplement 14, no. 3 (2021): 625. http://dx.doi.org/10.5506/aphyspolbsupp.14.625.

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5

Bito, Yoshitaka, Kensuk Sekihara, and Ryuichi Suzuki. "5297033 Data processing method in nuclear magnetic resonance measurement." Magnetic Resonance Imaging 13, no. 1 (January 1995): XVII. http://dx.doi.org/10.1016/0730-725x(95)90070-l.

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6

Urbano-Bojorge, Ana Lorena, Nazario Félix-González, Tamara Fernández, Francisco del Pozo-Guerrero, Milagros Ramos, and José Javier Serrano-Olmedo. "A Comparison of Magnetometry and Relaxometry Measures of Magnetic Nanoparticles Deposited in Biological Samples." Journal of Nano Research 31 (April 2015): 129–37. http://dx.doi.org/10.4028/www.scientific.net/jnanor.31.129.

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The Alternating Gradient Field Magnetometer (AGFM) is an instrument whose high sensitivity (10-8 emu) allows the detection of small amounts of magnetic nanoparticles (MNPs) with high accuracy. Over the last few years, different magnetic techniques have been used for in vitro measurements of magnetic nanostructures inside biological tissues. However, in vivo studies about their distribution within the body are very scarce because their dispersion, after being delivered, reduces their magnetic signal and hinders detection. In this paper we compare the longitudinal relaxation time (T1) and magnetization measurements in mice's biological tissues for the tracking of MNPs after of an injection of iron oxide nanoparticles. Furthermore, we have correlated the AGFM data with Fast Field Cycling NMR Relaxometry (FFCNMR Relaxometry) measurements with histological analysis. The results have demonstrated that these techniques are useful for detecting minute amounts of MNPs in excised organs after in-vivo comparable to other more conventional techniques for the measurement of MNPs biodistribution and clearance. Details about the preparation of the in vivo samples, measurement protocol and statistical data processing are given.
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7

Хомутов, Сергей, and Sergey Khomutov. "XVI IAGA workshop on geomagnetic observatory instruments, data acquisition and processing. Hyderabad, India, October 2014: Brief review XVI IAGA workshop on geomagnetic observatory in-struments, data acquisition and processing. Hyderabad, India, October 2014: Brief review." Solnechno-Zemnaya Fizika 1, no. 4 (December 17, 2015): 86–89. http://dx.doi.org/10.12737/13572.

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The brief review of the XVI IAGA Workshop on Geomagnetic Observatory Instruments Data Acquisition and Processing (Hyderabad, India, October 2014) is presented. Much attention is given to new magnetometers and software for practical work of magnetologists as well as to archive data. Reports on new devices point to the tendency that in the near future, the technique for obtaining the total field vector data adopted by INTERMAGNET will remain changeless as the combination of absolute (manual) and variation measurements. Besides, a low interest of the community to software necessary for full processing of magnetic measurements directly in observatories should be also noticed.
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8

Yanis, Muhammad, Marwan Marwan, Bukhari Bukhari, and Nazli Ismail. "THE DIFFERENT MAGNETIC RESULTS OF ANEMI AND PPM MEASUREMENTS ON THE BURIED REMAINS OF A 13TH CENTURY FORTRESS." Jurnal Natural 16, no. 2 (September 19, 2016): 33–36. http://dx.doi.org/10.24815/jn.v16i2.5018.

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This study aimed to evaluate the different magnetic results of an electromagnetic induction with proton magnetometer measurements on an archaeological site. The electromagnetic induction allows measuring both the apparent magnetic susceptibility in part per thousand (ppt) and the apparent electrical conductivity in millisiemens (mS/m). A proton magnetometer measures the total magnetic intensity in nanotesla (nT), caused by the induced and remanent magnetisations. An archaeological site where historical documents indicated the presence of a 13th century fortress that built by Lamuri Sultanate was selected as a test area. The measurement were conducted by divided the study area into 10 profiles.Some standard data processing have been applied to the measured data. The result of the first survey with electromagnetic induction showed low magnetic anomalies in the buried remains of Lamuri fortress. The similar value are shown as well by low magnetic field intensity in magnetometer measurement.
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9

Pedersen, L. B., and T. M. Rasmussen. "The gradient tensor of potential field anomalies: Some implications on data collection and data processing of maps." GEOPHYSICS 55, no. 12 (December 1990): 1558–66. http://dx.doi.org/10.1190/1.1442807.

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The full gradient tensor is presently not measured routinely onboard airplanes or on land. This paper describes some improvements that can be made in strategies of data collection and in processing of potential field maps if such tensor measurements were available. We suggest that, in addition to producing for example standard total field anomaly maps, the invariants of the tensor be mapped. Strikes of magnetic or gravimetric structures may be determined from minimizing the power in the first row and column of the tensor. Invariants can be looked upon as nonlinear filters enhancing sources with big volumes. Their lateral resolution is superior to that of the field proper and, for a given resolution, the flight altitude and separation between flight lines can be increased compared with the standard mode of operation. In airborne surveys the distance between flight lines is normally much larger than the height above the ground. This may introduce severe aliasing effects in the direction perpendicular to the flight lines. By increasing the flight altitude, aliasing effects are reduced at the expense of lateral resolution which, however, may be improved by mapping the tensor invariants in addition to the magnetic field. The estimated gradient tensor from total field magnetic data over the Siljan impact region shows that the magnetic properties of the area are very nonuniform even from a height of 430 m above the topography. The nonlinear filters discriminate major anomalies into separate units.
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10

Guerin, Roger, Alain Tabbagh, and Pierre Andrieux. "Field and/or resistivity mapping in MT-VLF and implications for data processing." GEOPHYSICS 59, no. 11 (November 1994): 1695–712. http://dx.doi.org/10.1190/1.1443557.

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The ratio of the horizontal electric and magnetic components of the electromagnetic field generated by a radio transmitter in the very low frequency (VLF) range is used in MT-VLF resistivity mapping to determine the apparent resistivity of the ground. A theoretical calculation of the responses of simple 2-D and 3-D prismatic bodies shows that the measurable lateral variations in both fields are independent, uncoupled, and correspond to frequency‐independent, static variations. It is advantageous therefore to process and map the fields separately. Processing methods used in gravimetry and magnetics are especially appropriate in correcting the apparent anisotropy related to the horizontal polarization of the primary field and in integrating (upward continuation) the high‐frequency spatial variations. The different processes tested on a synthetic case and on data obtained at the Centre de Recherches Géophysiques (CRG) test site showed how to eliminate shallow features and a current channeling conductor to favor the anomaly of a fault. A third example with a hydrogeological application shows the advantages of this method over Wenner direct‐current resistivity measurements.
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11

de Barros Camara, Erick, and Suze Nei Pereira Guimarães. "Magnetic airborne survey – geophysical flight." Geoscientific Instrumentation, Methods and Data Systems 5, no. 1 (June 6, 2016): 181–92. http://dx.doi.org/10.5194/gi-5-181-2016.

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Abstract. This paper provides a technical review process in the area of airborne acquisition of geophysical data, with emphasis for magnetometry. In summary, it addresses the calibration processes of geophysical equipment as well as the aircraft to minimize possible errors in measurements. The corrections used in data processing and filtering are demonstrated with the same results as well as the evolution of these techniques in Brazil and worldwide.
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12

Legchenko, Anatoly V., and Oleg A. Shushakov. "Inversion of surface NMR data." GEOPHYSICS 63, no. 1 (January 1998): 75–84. http://dx.doi.org/10.1190/1.1444329.

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The main advantage of the surface nuclear magnetic resonance (NMR) method compared to other geophysical methods in the field of groundwater investigation is the ability to measure an NMR signal directly from the water molecules. An NMR signal stimulated by an alternating current pulse through an antenna at the surface, confirms the existence of water in the subsurface with a high degree of reliability. The NMR signal amplitude depends on the pulse parameter (the product of the pulse amplitude and its duration), bulk water volume, and water depth. Measurements are performed while varying the pulse parameter, and subsequent data processing reveals the number of water‐saturated layers, and data concerning their depth, thickness, and water content. One of the major problems in the practical application of the NMR method is the very weak signal (<3000 nV): hence the problem of signal to noise ratio (S/N). S/N can be improved by stacking the signal, but measurement time is increased. We have developed an algorithm that minimizes the number of measurements (number of different values of the pulse parameter) without a loss of inversion accuracy for a given S/N ratio, making it possible to determine a set of optimal pulses for the measurements. NMR measurements are also sensitive to the electrical conductivity of the subsurface; an electrically conductive subsurface causes variations in the depth of investigation and in the vertical resolution of the method. Experience gained from application of the method has proven that both the inversion algorithm and the analysis of the problem are efficient.
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13

Golomolzina, Diana Rashidovna, Maxim Alexandrovich Gorodnichev, Evgeny Andreevich Levin, Alexander Nikolaevich Savostyanov, Ekaterina Pavlovna Yablokova, Arthur C. Tsai, Mikhail Sergeevich Zaleshin, et al. "Advanced Electroencephalogram Processing." International Journal of E-Health and Medical Communications 5, no. 2 (April 2014): 49–69. http://dx.doi.org/10.4018/ijehmc.2014040103.

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The study of electroencephalography (EEG) data can involve independent component analysis and further clustering of the components according to relation of the components to certain processes in a brain or to external sources of electricity such as muscular motion impulses, electrical fields inducted by power mains, electrostatic discharges, etc. At present, known methods for clustering of components are costly because require additional measurements with magnetic-resonance imaging (MRI), for example, or have accuracy restrictions if only EEG data is analyzed. A new method and algorithm for automatic clustering of physiologically similar but statistically independent EEG components is described in this paper. Developed clustering algorithm has been compared with algorithms implemented in the EEGLab toolbox. The paper contains results of algorithms testing on real EEG data obtained under two experimental tasks: voluntary movement control under conditions of stop-signal paradigm and syntactical error recognition in written sentences. The experimental evaluation demonstrated more than 90% correspondence between the results of automatic clustering and clustering made by an expert physiologist.
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14

Khokhlov, Andrey. "Processing Non-Gaussian Data Residuals in Geomagnetism." Applied Sciences 12, no. 4 (February 17, 2022): 2097. http://dx.doi.org/10.3390/app12042097.

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Some time ago, we considered non-Gaussian shapes of histograms of quantities that were related to residuals in data: we showed at a qualitative level that non-Gaussianity is most likely the result of mixing of Gaussian distributions. In this addendum, we argue that there is a quantitative description that can be used in fairly general situations. Briefly, we present here the same magnetic measurement data that were reported in the original publication: Khokhlov, A.; Hulot, G. On the cause of the non-Gaussian distribution of residuals in geomagnetism. Geophys. J. Int. 2017, 209, 1036–1047.
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15

Larsen, Jakob Juul, and Ahmad A. Behroozmand. "Processing of surface-nuclear magnetic resonance data from sites with high noise levels." GEOPHYSICS 81, no. 4 (July 2016): WB75—WB83. http://dx.doi.org/10.1190/geo2015-0441.1.

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The applicability of surface nuclear magnetic resonance (NMR) in investigations of groundwater is often limited by high noise levels in many areas of interest. We have evaluated measurements from a high-noise-level area in Ristrup, Denmark, recorded with a Numis Poly instrument. Standard multichannel filtering techniques for noise reduction are inadequate for several data sets acquired in this area, and surface-NMR signals cannot be resolved from the acquired data. Based on a careful assessment of the frequency content of the data, we have determined how a model-based noise reduction approach can be generalized and used to subtract two harmonic noise components from the data. Reliable surface-NMR data can be extracted from the noise-reduced data. Moreover, we have determined the impact of the proposed processing approaches on our inversion results, and we have also developed an example in which the proposed methodology allowed us to reveal and avoid an otherwise overlooked contamination of the reference coil signals with a surface-NMR signal. No borehole data were available for the investigated sites, and the validity of the noise reduction approach was instead verified using a synthetic five-layer model embedded in noise-only records from Ristrup. Our results have determined that a careful processing of the recorded data made it possible to extract surface-NMR data in more places of interest.
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16

WANG Shuang, 王. 爽., 韩. 燮. HAN Xie, 李. 晓. LI Xiao, 王志斌 WANG Zhi-bin, 景. 宁. JING Ning, 陈友华 CHEN You-hua, and 陈媛媛 CHEN Yuan-yuan. "Digital phase-locked data processing for ellipsometric parameter measurements based on photoelastic modulation." Optics and Precision Engineering 26, no. 6 (2018): 1314–21. http://dx.doi.org/10.3788/ope.20182606.1314.

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17

Di Fiore, B., D. Chianese, A. Loperte, G. Conte, A. Dibenedetto, P. Vitti, O. Voza, and E. Greco. "First geophysical results in the Archeological sites of Θούρια (Péloponnèse, Hellas) and Sibari-Thurii (southern Italy)." Bulletin of the Geological Society of Greece 40, no. 3 (June 5, 2018): 1080. http://dx.doi.org/10.12681/bgsg.16827.

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High resolution techniques for data acquisition and processing procedures are increasingly applied in near-surface geophysics for archaeology. In this paper we present the preliminary results of two geophysical measurements campaigns aimed to the investigation of buried remains in the archaeological sites of Θουρία (Péloponnèse, Hellas) and Sibari (Southern Italy). In the first field survey the geophysical approach involved the integrated application of the geoelectrical and magnetic methods and an innovative tomographic analysis for the inversion of both resistivity and magnetic data. In the second case, we carried out high resolution magnetic measurements, interpreted by means of the use of an appropriate filtering procedure. The applied data inversion allows us to provide reliable space patterns of the most probable specific target boundaries, improving the information quality of geophysical methods. The results obtained at this early stage of data processing confirm some archaeological hypothesis about the investigated areas and confirm that the use of integrated geophysical methods allows the archaeologists to reduce the time and the costs of their surveys.
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18

Annetts, David. "Magnetic tensor gradiometry and marine CSEM." APPEA Journal 50, no. 2 (2010): 711. http://dx.doi.org/10.1071/aj09075.

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In recent times, surveys employing tensor gradiometers have been used in mineral exploration. Some reasons for this are potential advantages such as improved resolution, data interpolation, noise suppression and relative insensitivity to survey orientation. The last two potentialities are particularly germane to marine CSEM surveys, which are typically sparsely sampled and require processing of measured fields to ensure that the correct vector component is analysed. In a series of numerical modelling studies of typical frequency-domain CSEM surveys in both shallow and deep water columns, this paper shows that tensor gradient measurements have advantages over conventional CSEM measurements in terms of target definition, especially when survey lines do not fall over target centres.
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D'Antona, G., L. Di Rienzo, R. Ottoboni, and A. Manara. "Processing magnetic sensor array data for AC current measurement in multiconductor systems." IEEE Transactions on Instrumentation and Measurement 50, no. 5 (2001): 1289–95. http://dx.doi.org/10.1109/19.963199.

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20

Aprianto, Romi, and Kirbani Sri Brtopuspito. "Analisis Suseptibilitas Magnetik Batuan Pengeboran di Blok Elang Sumbawa." Jurnal Pendidikan Fisika dan Teknologi 1, no. 3 (March 14, 2017): 226. http://dx.doi.org/10.29303/jpft.v1i3.263.

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Magnetic susceptibility measurements have been performed in 6 holes hole (ROM-001, ROM-002, ROM-003, ROM-004, ROM-005, dan ROM-006) in Elang, Sumbawa. This study aimed to determine the correlation between magnetic susceptibility in holes. Magnetic measurements were performed using Suceptibility Meter KT-10. Data processing is done by using software Oasis Montaj Drillhole Plotting to analyze correlations and relationships between holes. The interpretation shows that there’s correlation between magnetic susceptibility values with intrusion system of phorphyry Cu-Au. The highest range of magnetic susceptibility value is in Chlorite Sericite Zone (pgm) 0.19x10-3 SI to 1459x10-3 SI. From the magnetic susceptibility values have been estimated position of the intrusion, which is in the ROM 006.
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Logan, K. "The application of airborne geophysics to epithermal gold exploration in Eastern Misima Island, Papua New Guinea." Exploration Geophysics 20, no. 2 (1989): 85. http://dx.doi.org/10.1071/eg989085.

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Misima Island is situated 625 km east southeast of Port Moresby in Papua New Guinea. A detailed airborne magnetic and radiometric survey was carried out over the eastern portion of the island which contains the Umuna epithermal gold deposit.The purpose of the survey was to improve the understanding of surface and underlying geology and assist the regional mineral exploration of the area.In situ magnetic susceptibility measurements were taken within the survey area to determine the magnetic properties of the various Palaeocene-Miocene metasedimentary sequences and Miocene porphyritic felsic intrusives.The interpretation of the airborne magnetic data was constrained by susceptibility measurements, magnetic modelling and regional geological mapping. Computer processing included the use of reduction to the pole and pseudo gravimetric transforms.Variable density and type of vegetation cover on the island limited previous interpretations of the airborne radiometric data. The data was reprocessed using principal components analysis of the potassium and total count radiometric data.
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Zhang, Xing Dong, Xiao Hong Meng, and Liang Hui Guo. "Kalman Filter Processing Applications for Motion Noise." Applied Mechanics and Materials 644-650 (September 2014): 3964–67. http://dx.doi.org/10.4028/www.scientific.net/amm.644-650.3964.

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In geophysics exploration, using gradient tensor instead of the full magnetic field gradient has many advantages, which magnetic gradient tensor data to better describe small anomalies. However, the measurement of magnetic gradiometer contains a very complex motion noise, separating the motion noise from the signal component is a large challenge. In this paper, we show the expression for the magnetic gradient tensor, and then through model tests proved the Kalman filter good filtering effect.
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Costabel, Stephan, Thomas Günther, Raphael Dlugosch, and Mike Müller-Petke. "Torus-nuclear magnetic resonance: Quasicontinuous airborne magnetic resonance profiling by using a helium-filled balloon." GEOPHYSICS 81, no. 4 (July 2016): WB119—WB129. http://dx.doi.org/10.1190/geo2015-0467.1.

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The application of surface nuclear magnetic resonance (NMR) measurements, although proven to be valuable for various hydrogeological issues, is in practice often limited to single 1D surveys because measurement progress is slow. First, large stacking rates are necessary to overcome the low signal-to-noise ratio and, second, time and effort are required to move the equipment and to place the measurement loops in the field. We have evaluated a novel approach to cope with the latter. We have assessed and tested a data acquisition scheme based on a torus-shaped helium-filled balloon carrying the loop and moving it rapidly from one to the next measurement position along the profile lines. We have referred to this system as Torus-NMR. We have showed the feasibility of the system to deliver reliable results using common processing and inversion. Surface NMR field data are acquired at successively overlapping positions along a test profile using the Torus-NMR system. To take advantage of the faster loop setup, the overall measurement time of the single NMR soundings is reduced by reducing the number of stacks, whereas the number of soundings is increased to obtain highly overlapping coverage. Regarding a single measurement position, a significant loss of vertical resolution must be accepted that can, however, be compensated to some extent by inverting the complete profile data set simultaneously using a laterally constrained inversion. We have found that for simple subsurface models, e.g., a layered earth with up to three layers, the proposed scheme provided reasonable results, which were demonstrated using synthetic and real field data. We do not expect the Torus-NMR concept to replace 2D data acquisition schemes if high spatial resolution is required. However, we expect fields of application that aim at rapid lateral overview of how specific hydrogeological parameters of shallow aquifers are distributed over large catchment-scale areas.
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Putri, Maizza Nadia, Kusworo Adi, M.Irwan Katili, Sidin Hariyanto, and Dwi Rochmayanti. "COMPARISON MEASUREMENT AND CALCULATION OF BRAIN TUMOR IN MRI MODALITIES UTILISING SPIN-ECHO PULSE SEQUENCE T1-WEIGHTED CONTRAST AND DIGITAL IMAGE PROCESSING APPLICATIONS." Journal of Vocational Health Studies 6, no. 2 (November 1, 2022): 151–57. http://dx.doi.org/10.20473/jvhs.v6.i2.2022.151-157.

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Background: Evaluation of brain tumor MRI image results performed by radiologists employing the linear measurement method has several weaknesses and is sensitive to subjectivity. Purpose: To compare the results of measurements and calculations of brain tumors utilizing the linear measurement method on the Siemens 1.5 Tesla MRI modality employing pulse sequence spin echo with T1 contrast weighting compared with the results of measurements and calculations of brain tumors utilizing the active contour segmentation method. Method: An experimental study was conducted on 32 MRI images. Result: The study’s findings indicated that the linear measurement was more significant than the active contour segmentation method (p-value<0,05). The results were obtained by calculating the sensitivity and specificity values of the diagnostic test, which were calculated to be 87.5%. Conclusion: The active contour segmentation method applied to pulse sequence spin-echo T1-weighted contrast can be utilized as an alternative measurement and calculation of brain tumors with a sensitivity and specificity value of 87.5%. Further research suggests developing a Matlab application to compare the results of measurements and calculations of brain tumors on acquiring 3D image magnetic resonance imaging data.
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Di Rienzo, Luca, Alberto Cosmai, and Stephan Russenschuck. "Post-Processing Magnetic Measurement Data of Accelerator Magnets by the Boundary Element Method." IEEE Transactions on Magnetics 53, no. 6 (June 2017): 1–4. http://dx.doi.org/10.1109/tmag.2017.2652119.

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Elias, M., and H. G. Maas. "INVESTIGATION ON MULTI-SENSOR FUSION STRATEGIES FOR IMPROVED ORIENTATION DETERMINATION IN MOBILE PHONE IMAGING APPLICATIONS." ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences V-1-2020 (August 3, 2020): 181–87. http://dx.doi.org/10.5194/isprs-annals-v-1-2020-181-2020.

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Abstract. Thanks to the rapid technological progress in the field of mobile devices, smartphones are increasingly becoming valuable for science. They can serve as photogrammetric measurement devices with built-in cameras, micro-electro-mechanical systems for orientation and position assessment, as well as powerful processing units allowing field-based data acquisition and processing. This paper outlines a comprehensive investigation focusing on the accuracy and stability of smartphone camera rotation parameters determined by built-in smartphone sensors. For that purpose, the rotation parameters were measured under a range of different conditions. Four test scenarios were defined considering indoor- and outdoor measurements using three different devices being in static and dynamic modes. Furthermore, the influence of magnetic perturbations was investigated. The rotation parameters were determined from the measurements applying different sensor fusion approaches. Reference values for accuracy assessment were provided by a superior precision inertial measurement unit that measured the rotation parameters simultaneously to the smartphone in each experiment. The analysis of the smartphone-based rotation parameters, separated in the Euler angles azimuth, pitch and roll, shows average accuracies below 2° for pitch and roll. In comparison, azimuth shows significantly lower accuracies of more than 30° especially when the smartphone is in motion and when it is exposed to magnetic perturbations. In this regard, advanced multi-sensor fusion approaches were examined that handle such interferences to considerably improve the accuracy of azimuth measurements. In conclusion, a summary of accuracies and stabilities to be expected from smartphone sensors is given referring to ambient conditions and investigated sensor fusion strategies.
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Thorsen, Arve K., Tor Eiane, Holger F. Thern, Paal Fristad, and Stephen Williams. "Magnetic Resonance in Chalk Horizontal Well Logged With LWD." SPE Reservoir Evaluation & Engineering 13, no. 04 (August 5, 2010): 654–66. http://dx.doi.org/10.2118/115699-pa.

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Summary This paper describes geological and petrophysical evaluation of a new structure of a mature field to evaluate the reservoir potential in unproduced reservoir zones. The well was drilled in a carbonate with variations in rock quality and with minor subfaulting occurring. Gamma ray (GR), resistivity, density, neutron, and image services were used in the horizontal part of the well in addition to magnetic resonance (MR). To achieve the best possible real-time wellbore placement, reservoir navigation and continuous follow-up on the horizontal log interpretation were performed during drilling. For the first time, a low-gradient-MR-while-drilling technology was deployed in a virgin carbonate horizontal well on the Norwegian Continental Shelf. The MR service was run to obtain porosities (including partitioning of movable and bound fluids), hydrocarbon (HC) saturations, and permeability estimates. Fluid saturations based on traditional methods and the MR were evaluated and compared by core data, enhancing the understanding of the measurement and the reservoir. For post-processing, the MR data were integrated and interpreted together with the other measurements performed in the well, delivering an accurate and consistent reservoir description. The first part of the horizontal part of the well was drilled with conductive drilling fluid and the latter part with nonconductive drilling fluid. Laboratory measurements for the two mud filtrates were performed to understand the influence of the two different drilling-fluid types on the MR measurements. In the absence of water-based mudfiltrate invasion, the MR data show good agreement with saturations from core, confirming the quality and reliability of the MR data. Comparison of the MR T2 distributions and volumetrics with image data indicates that even fine variations in rock quality and lithology are reliably resolved by the MR data. Before logging, old core data were used to refine the constants used in the Timur-Coates MR permeability equation, which quantitatively tracks changes in reservoir quality. The values were calibrated when Timur-Coates constants were derived from the well's core plugs.
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Vega, Jorge R., Luis M. Gugliotta, Verónica D. G. Gonzalez, and Gregorio R. Meira. "Latex particle size distribution by dynamic light scattering: novel data processing for multiangle measurements." Journal of Colloid and Interface Science 261, no. 1 (May 2003): 74–81. http://dx.doi.org/10.1016/s0021-9797(03)00040-7.

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Nauber, Richard, Lars Büttner, and Jürgen Czarske. "Measurement uncertainty analysis of field-programmable gate-array-based, real-time signal processing for ultrasound flow imaging." Journal of Sensors and Sensor Systems 9, no. 2 (July 31, 2020): 227–38. http://dx.doi.org/10.5194/jsss-9-227-2020.

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Abstract. Research in magnetohydrodynamics (MHD) aims to understand the complex interactions of electrically conductive fluids and magnetic fields. A promising approach for investigating complex instationary flow phenomena are lab-scale experiments with low-melting alloys. They require a noninvasive flow instrumentation for opaque liquids with a high spatiotemporal resolution, a low velocity uncertainty and a long measurement duration. Ultrasound Doppler velocimetry can achieve multiplane, multicomponential flow imaging with multiple linear ultrasound arrays. However the average raw data output amounts to 1.2 GBs−1 at a frame rate of 33 Hz in a typical configuration for 200 transducers. This usually prevents long-duration measurements when offline signal processing is used. In this paper, we propose an online signal-processing chain for pulsed-wave Doppler velocimetry that is tailored to the specific requirements of flow imaging for lab-scale experiments. The trade-off between measurement uncertainty and computational complexity is evaluated for different algorithmic variants in relation to the Cramér–Rao bound. By utilizing selected approximations and parameter choices, a prepossessing could be efficiently implemented on a field-programmable gate array (FPGA), enabling a typical reduction of the data bandwidth of 6.5:1 and online flow visualization. We validated the performance of the signal processing on a test rig, yielding a velocity standard deviation that is a factor of 3 above the theoretical limit despite a low computational complexity. Potential applications for this signal processing include multihour flow measurements during a crystal-growth process and closed-loop velocity feedback for model experiments.
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Manalo, P. C., C. B. Dimalanta, B. R. B. Villaplaza, W. W. Brown, and G. P. Yumul. "Magnetic Exploration of Structurally Controlled Mineralization at Low Latitudes: A Case from the Masara Gold District, Mindanao, Philippines." Economic Geology 112, no. 7 (November 1, 2017): 1807–17. http://dx.doi.org/10.5382/econgeo.2017.4530.

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Abstract Magnetic data transformations are applied to the high-resolution magnetic data from the Masara gold district in the southern Philippines to enhance features related to a porphyry copper prospect and epithermal gold deposit. Using several filtering methods and structural mapping techniques, we were able to highlight the signal coming from a shallow chlorite-sericite alteration zone. Although the epithermal veins are mainly composed of nonmagnetic minerals, calculation of the tilt derivative of the magnetic grid revealed linear features that are coincident with the surface projection of the gold-bearing veins. Furthermore, dip directions of the magnetic sources were determined using Euler deconvolution, and they were found to coincide with the dip directions of the veins as determined by structural measurements at different underground levels. Aside from showing the utility of the magnetic methods in epithermal gold deposit exploration, this study also demonstrates that challenges of processing and interpreting magnetic anomalies in areas near the equator can be overcome. This research outlines a processing workflow that can be adopted for further investigation of other mineralized areas.
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Sánchez-Puga, Pablo, Javier Tajuelo, Juan Pastor, and Miguel Rubio. "Dynamic Measurements with the Bicone Interfacial Shear Rheometer: Numerical Bench-Marking of Flow Field-Based Data Processing." Colloids and Interfaces 2, no. 4 (December 7, 2018): 69. http://dx.doi.org/10.3390/colloids2040069.

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Flow field-based methods are becoming increasingly popular for the analysis of interfacial shear rheology data. Such methods take properly into account the subphase drag by solving the Navier–Stokes equations for the bulk phase flows, together with the Boussinesq–Scriven boundary condition at the fluid–fluid interface and the probe equation of motion. Such methods have been successfully implemented on the double wall-ring (DWR), the magnetic rod (MR), and the bicone interfacial shear rheometers. However, a study of the errors introduced directly by the numerical processing is still lacking. Here, we report on a study of the errors introduced exclusively by the numerical procedure corresponding to the bicone geometry at an air–water interface. In our study, we set an input value of the complex interfacial viscosity, and we numerically obtained the corresponding flow field and the complex amplitude ratio for the probe motion. Then, we used the standard iterative procedure to obtain the calculated complex viscosity value. A detailed comparison of the set and calculated complex viscosity values was made in wide ranges of the three parameters herein used, namely the real and imaginary parts of the complex interfacial viscosity and the frequency. The observed discrepancies yield a detailed landscape of the numerically-introduced errors.
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32

Grunewald, Elliot, and Rosemary Knight. "Nonexponential decay of the surface-NMR signal and implications for water content estimation." GEOPHYSICS 77, no. 1 (January 2012): EN1—EN9. http://dx.doi.org/10.1190/geo2011-0160.1.

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Noninvasive surface nuclear magnetic resonance (SNMR) measurements can yield direct and quantitative estimates of water content in the near surface. A fundamental assumption that is always made in the analysis of SNMR data is that the measured signal exhibits an exponential decay. Although the assumption of exponential decay is frequently valid, it can be shown that in the presence of an inhomogeneous magnetic field, the decay may be nonexponential in form. Simulated SNMR data were used to explore how the decay shape will vary with certain environmental and measurement conditions and to assess how nonexponential decay will affect SNMR-based estimates of water content. Results derived from analytical and pore-scale modeling demonstrated that the shape of the decay depends strongly on both pore geometry and the statistics of the regional or pore-scale magnetic field. In particular, the decay is most likely to be nonexponential when pores are large and when a strongly inhomogeneous magnetic field is present. For conditions in which the SNMR signal cannot be accurately modeled as exponential, standard processing approaches were found to result in significant errors in estimated water content—specifically, water content tends to be overestimated. Analysis of data misfits suggests that, in practice, it will be difficult to directly identify errors associated with nonexponential decay based only on the measured signal. Therefore, a description of the conditions leading to nonexponential decay and the implications for water content estimates is useful to support improved interpretation of SNMR measurements.
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Heng, S., and W. Z. Black. "Temperature Mapping of Localized Hot Spots on Microelectronic Chip Surfaces." Journal of Electronic Packaging 113, no. 3 (September 1, 1991): 286–93. http://dx.doi.org/10.1115/1.2905408.

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This paper describes the use of digital image processing in conjunction with an infrared imaging apparatus to locate and quantify “micro” hot spot temperatures on the surface of energized microelectronic chips. Briefly, the temperature mapping/processing procedure creates emissivity maps for the surface of the chip at different isothermal conditions. The emissivity map images are digitized and stored as a 512 × 512 pixel array, of which 400 lines contain IR information. Apparent temperature measurements are then collected with the chip energized in its normal operating environment. These apparent temperature data are digitized and stored as a 512 × 512 integer array using the same format as the digitized emissivity data. Before correcting for emissivity variations, the apparent temperature images are rectified using digital image processing to precisely overlay the spatial coordinates of the emissivity map. Finally, actual temperature maps are obtained by correcting the apparent temperature data for the local emissivity variations and background reflections. The computer driven measurement technique has been applied to the task of measuring localized temperatures on areas as small as 30 μm on the surface of an energized chip to an accuracy of ±1°C once the surface emissivity is accurately known. The infrared equipment, image processing hardware and supporting software are used to measure the temperature distribution on the surface of a 4.7 mm × 4.7 mm energized chip. IR measured temperatures at isolated locations on the chip are compared with results obtained by the resistance-temperature technique. Since the resistance-temperature technique provides an area-averaged temperature for the energized region, the result obtained from the high resolution IR measurements yields higher localized temperatures. Results are presented for peak surface temperatures up to 100°C and maximum heat flux values of 7.9x106 W/m2. A separate set of infrared measurements are used to predict the influence of surface emissivity on the accuracy of the temperature measurements.
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Larsen, Jakob Juul. "Model-based subtraction of spikes from surface nuclear magnetic resonance data." GEOPHYSICS 81, no. 4 (July 2016): WB1—WB8. http://dx.doi.org/10.1190/geo2015-0442.1.

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Surface nuclear magnetic resonance (surface NMR) has progressed significantly in recent years due to advances in instrumentation. In particular, the introduction of multichannel surface NMR instruments has been effective in improving the signal-to-noise ratio. The current methodology for noise reduction with multichannel instruments is, however, inadequate in complex noise environments, and there is a need for improved signal processing. We have evaluated a study of impulsive noise (spikes) in surface NMR data acquired with a Numis Poly instrument. We have determined how the spectral content can be used to classify spikes as originating from electric fences or sferics. Measurements of spikes from two electric fences were evaluated. The spikes were highly deterministic and can be modeled as impulsive excitations of the band-pass filter in the surface NMR receiver system. We investigated the feasibility of a model-based approach for subtraction of electric fence spikes. Model-based subtraction was shown to be possible, but it is limited by accidental fitting of the NMR signal in its current embodiment. We evaluated an example of a surface NMR data set in which subtraction of powerline harmonic noise and electric fence spike noise removed all coherence in the multichannel data, and the consequences for further noise reduction using multichannel methods were developed.
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Zheng, Liang, Zhi Hua Ying, Wei Peng Kong, Feng Sun, Wei Wei Hu, Jun Ming Xu, and Hui Bin Qin. "Design and Realization of the Dynamic Magnetic Measurement System for Soft Magnetic Material." Advanced Materials Research 346 (September 2011): 719–23. http://dx.doi.org/10.4028/www.scientific.net/amr.346.719.

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A dynamic magnetic measurement system for soft magnetic material based on virtual instrument technology is presented. High frequency AC excitation power supply is adopted to drive soft magnetic material. High speed data transport system composed by FPGA chip ALTERA EP1C12Q240C8N and USB microcontroller Cypress CY7C68013A. The problem of phase-shift of hardware integrator which is difficult to control is solved by digital integration. LabVIEW with powerful data processing capabilities is used to simplifies the hardware structure and improve the testing accuracy and automation level of measurement. The paper also points out problems of digital integration and gives a solution.
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Spinolo, Giorgio, Gaetano Chiodelli, Aldo Magistris, and Umberto Anselmi Tamburini. "Data Processing for Electrochemical Measurements with Frequency Response Analyzers: I . Error Analysis and Accuracy Tests." Journal of The Electrochemical Society 135, no. 6 (June 1, 1988): 1419–24. http://dx.doi.org/10.1149/1.2096012.

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37

Druzhinin, Vladimir, Aleksandr Korol, Natalya Melnikova, Sergey Serednyakov, and Ilya Surin. "Time measurement with the SND electromagnetic calorimeter." EPJ Web of Conferences 245 (2020): 01034. http://dx.doi.org/10.1051/epjconf/202024501034.

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The SND is a non-magnetic detector deployed at the VEPP-2000 e+e− collider (BINP, Novosibirsk) for hadronic cross-section measurements in the center of mass energy range below 2 GeV. The important part of the detector is a three-layer hodoscopic electromagnetic calorimeter (EMC) based on NaI(Tl) counters. Until the recent EMC spectrometric channel upgrade, only the measurement of the energy deposition in counters was possible. New EMC signal digitizing electronics based on FADC allow us to obtain also the signal arrival time. The new electronics and supporting software, including digitized signal processing algorithms, are now used for data taking in the ongoing experiment. We discuss the amplitude and time extraction algorithms, the new system performance on experimental events and how this time measurement can be applied to physics analysis.
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Philiastides, Marios G., Tao Tu, and Paul Sajda. "Inferring Macroscale Brain Dynamics via Fusion of Simultaneous EEG-fMRI." Annual Review of Neuroscience 44, no. 1 (July 8, 2021): 315–34. http://dx.doi.org/10.1146/annurev-neuro-100220-093239.

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Advances in the instrumentation and signal processing for simultaneously acquired electroencephalography and functional magnetic resonance imaging (EEG-fMRI) have enabled new ways to observe the spatiotemporal neural dynamics of the human brain. Central to the utility of EEG-fMRI neuroimaging systems are the methods for fusing the two data streams, with machine learning playing a key role. These methods can be dichotomized into those that are symmetric and asymmetric in terms of how the two modalities inform the fusion. Studies using these methods have shown that fusion yields new insights into brain function that are not possible when each modality is acquired separately. As technology improves and methods for fusion become more sophisticated, the future of EEG-fMRI for noninvasive measurement of brain dynamics includes mesoscale mapping at ultrahigh magnetic resonance fields, targeted perturbation-based neuroimaging, and using deep learning to uncover nonlinear representations that link the electrophysiological and hemodynamic measurements.
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39

Jeanguillaume, C., P. Ballongue, M. Tencé, and C. Colliex. "Developments in Processing Multisignal Imaging in STEM." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 1 (August 12, 1990): 118–19. http://dx.doi.org/10.1017/s0424820100179348.

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In an electron microscope, it is most important to optimize , for a given irradiation dose, the information extracted from the specimen . The STEM configuration is quite suited for such developments because it can easily be equipped with a set of detectors for recording simultaneous signals . When associated with novel processing modes, this multisignal imaging approach affords interesting developments in many fields of applications, as illustrated here on a simple example . A VG STEM with a magnetic spectrometer for energy loss studies, has been fitted with four different detection channels, as shown in Fig 1 . These are : the beam current measurement (Icur), the annular dark field image (Iadf), the unscattered (Iun ), and total inelastic signal (Iin ). These latter contributions are discriminated on two separate detectors after magnification of the EELS spectrum with a dedicated double gap electron lens, see (1) for complete description of the design. Before introducing these different data in the appropriate analytical expressions which involve sums, differences or ratios, it is necessary to evaluate their relative weights, i.e the ratios of their detection efficiencies. Following the general principle described in (2), a reconstructed image of the primary beam current is obtained as a suitable linear combination of the three other signals . New images can then be generated for : a) the enhancement of the signal to noise ratio in low dose condition; b) the separation of the elastic and inelastic contributions; c) the improvement of the Z contrast; d) the development of mass thickness measurements. These latter two aspects are illustrated in the present abstract.
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40

Ivanov, Alexey O., and Vladimir S. Zverev. "Dynamic Susceptibility of Ferrofluids: The Numerical Algorithm for the Inverse Problem of Magnetic Granulometry." Mathematics 9, no. 19 (October 2, 2021): 2450. http://dx.doi.org/10.3390/math9192450.

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The size-dependent properties of magnetic nanoparticles (MNP) are the major characteristics, determining MNP application in modern technologies and bio-medical techniques. Direct measurements of the nanosized particles, involved in intensive Brownian motion, are very complicated; so the correct mathematical methods for the experimental data processing enable to successfully predict the properties of MNP suspensions. In the present paper, we describe the fast numerical algorithm allowing to get the distribution over the relaxation time of MNP magnetic moments in ferrofluids. The algorithm is based on numerical fitting of the experimentally measured frequency spectra of the initial dynamic magnetic susceptibility. The efficiency of the algorithm in the solution of the inverse problem of magnetic granulometry is substantiated by the computer experiments for mono- and bi-fractional ferrofluids.
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41

Oravec, Milan, Pavol Lipovský, Miroslav Šmelko, Pavel Adamčík, Mirosław Witoś, and Jerzy Kwaśniewski. "Low-Frequency Magnetic Fields in Diagnostics of Low-Speed Electrical and Mechanical Systems." Sustainability 13, no. 16 (August 16, 2021): 9197. http://dx.doi.org/10.3390/su13169197.

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The magnetic field created by technical devices is a source of information. This information could be used in contactless diagnostics and predictive maintenance or for resolving problems along with standard NDT (nondestructive testing) methods, especially if we consider large, slow-speed devices, such as electromotors, transmissions, or generators. Identification of causalities of device failure processes with near magnetic field is one of the suitable NDT methods improving sustainability of systems. The measurements presented in the article were performed with the VEMA 04 fluxgate vector magnetometer with the DC-250 Hz bandwidth and 2 nT sensitivity. Postprocessing of the results was performed in the means of standard methods of discrete Fourier Transform, spectrogram creation and Wavelet Transform. The article presents data gathered during the measurement of a pair of extraction fans with power of 140 kW each and maximum revolutions up to 740 rev/min controlled by frequency converters and a single semi-Kaplan water power plant with 400 kW peak power at 1005 rev/min maximum generator speed. The measurements were performed before and after repairs of one of the ventilators in the ventilation system at 60% and 100% of maximal output power. The rotating magnetic fields of the fan electromotor stator, fan rotor revolutions, rotor slip frequency and ball-bearing frequencies were identified in frequency spectrums in the distance of 700 mm from fan electromotor axis in both cases. During the measurements on the semi-Kaplan turbine, the changes in states of mechanical and electrical components of the machine were monitored in the magnetic fields with increase of the power in the range of 0–95%, before and after phasing to the electrical grid. Standard processing methods, Discrete Fourier Transform, spectrograms and Discrete Wavelet Transform were used. In the spectrograms of the measured magnetic fields, the 1st–4th harmonics of the turbine shaft, generator shaft and also their side frequencies were identified. Significant changes of magnetic fields in time were identified in the area of 60–95% power. With the help of the Wavelet, transform intervals were identified where it is desirable to operate the turbine. The analyses of magnetic fields measurements performed on the power plant were compared with vibro-diagnostic principles.
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42

Zligostev, I. N., M. I. Epov, and A. V. Savluk. "On the measurement of the magnetic induction vector with the use of a three-component magnetometer placed on a mobile carrier." Russian Journal of Geophysical Technologies, no. 4 (March 11, 2022): 47–56. http://dx.doi.org/10.18303/2619-1563-2021-4-47.

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The article describes the use of a vector ferromagnetic magnetometer placed on an unmanned aerial vehicle (UAV). It is shown that solving inverse problems of magnetic prospecting for a vector aeromagnetic survey makes it possible to identify areas with different magnetization. We present a simple, based on standard libraries, software product for processing primary data of three-component fluxgate magnetometers, which allows correctly selecting the magnetic induction vector components when performing magnetic UAV surveys. To build maps, a method for graphical display of a vector field is proposed. On the example of a man-made object, we demonstrate that vector fields measured at different heights provide significantly more information than conventional electromagnetic induction measurements.
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43

Chen, Hsian-Min, Hung-Chieh Chen, Clayton Chi-Chang Chen, Yung-Chieh Chang, Yi-Ying Wu, Wen-Hsien Chen, Chiu-Chin Sung, Jyh-Wen Chai, and San-Kan Lee. "Comparison of Multispectral Image-Processing Methods for Brain Tissue Classification in BrainWeb Synthetic Data and Real MR Images." BioMed Research International 2021 (March 7, 2021): 1–12. http://dx.doi.org/10.1155/2021/9820145.

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Accurate quantification of brain tissue is a fundamental and challenging task in neuroimaging. Over the past two decades, statistical parametric mapping (SPM) and FMRIB’s Automated Segmentation Tool (FAST) have been widely used to estimate gray matter (GM) and white matter (WM) volumes. However, they cannot reliably estimate cerebrospinal fluid (CSF) volumes. To address this problem, we developed the TRIO algorithm (TRIOA), a new magnetic resonance (MR) multispectral classification method. SPM8, SPM12, FAST, and the TRIOA were evaluated using the BrainWeb database and real magnetic resonance imaging (MRI) data. In this paper, the MR brain images of 140 healthy volunteers ( 51.5 ± 15.8 y / o ) were obtained using a whole-body 1.5 T MRI system (Aera, Siemens, Erlangen, Germany). Before classification, several preprocessing steps were performed, including skull stripping and motion and inhomogeneity correction. After extensive experimentation, the TRIOA was shown to be more effective than SPM and FAST. For real data, all test methods revealed that the participants aged 20–83 years exhibited an age-associated decline in GM and WM volume fractions. However, for CSF volume estimation, SPM8-s and SPM12-m both produced different results, which were also different compared with those obtained by FAST and the TRIOA. Furthermore, the TRIOA performed consistently better than both SPM and FAST for GM, WM, and CSF volume estimation. Compared with SPM and FAST, the proposed TRIOA showed more advantages by providing more accurate MR brain tissue classification and volume measurements, specifically in CSF volume estimation.
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44

Daud, Yunus, Yasir Arafat, Dhara Adhnandya Kumara, Diah Anastasia Fortuna, Faris Maulana Yunus, Haidar Firdaus Avicienna, and Farhan. "An Updated Study of Discovering Blawan-Ijen Geothermal Prospect Area Using Gravity and Magnetic Methods." E3S Web of Conferences 73 (2018): 01007. http://dx.doi.org/10.1051/e3sconf/20187301007.

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The Blawan-Ijen volcanic complex is located in Bondowoso regencies, East Java province. The complex is expected to have geothermal system which is indicated by the occurrence of Blawan hotspring, acid lake on Ijen Crater and alterations. In 2017, measurements of gravity and magnetic methods have been conducted for the first time through the PITTA 2017 program. In 2018, further measurements are carried out to infill the previous data in order to strengthen the interpretation results. There are 151 stations obtained from each method until 2018. In this study, gravity method is used to detect the contrast density of an anomalous body while magnetic method is applied to discover the location of demagnetization zone. This paper presents the integration of both methods in geothermal exploration to determine the geothermal prospect area. The result of CBA and residual gravity indicated the existence of high gravity anomaly in the center to the southwest of the study area. Moreover, after processing RTP on magnetic data, there is the presence of low magnetic anomaly usually associated with demagnetization zone. Generally, the overall results supported one each other and pointed out the occurrence of the geothermal prospect possibly around the center of the study area.
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45

A, Lundberg, Lind E, Knutsson L, and Wirestam R. "Notes on quantitative susceptibility mapping reconstruction accuracy under challenging conditions: Phantom measurements and simulations." Journal of Medical and Scientific Research 10, no. 3 (July 1, 2022): 111–17. http://dx.doi.org/10.17727/jmsr.2022/10-21.

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Magnetic susceptibility can be assessed by quantitative susceptibility mapping (QSM), based on measured magnetic resonance imaging (MRI) phase data. The QSM reconstruction process is, however, mathematically challenging and still not fully robust. A signal-generating holmium [Ho(III)] aqueous solution with air-equivalent magnetic susceptibility was prepared, and used as a surrounding medium in a water phantom with tubes filled with a solution of gadolinium contrast agent at various concentrations. Extended analyses under controlled conditions were accomplished by simulations of the phantom construction. Without surrounding holmium solution, a gadolinium tube positioned centrally, parallel with B0, showed a susceptibility difference that agreed well with theoretical values, whereas a peripheral parallel tube position showed larger deviation. Orientation perpendicular to B0 resulted in less variation between the internal tube positions. Air-equivalent magnetic susceptibility corresponded to 16.5 mM Ho(III) solution. With surrounding holmium solution, several post-processing steps became challenging. Simulations indicated higher degree of underestimation when the theoretical susceptibility difference increased. Details in the mathematical implementation, for example, background field removal can strongly influence the result. Simulated results were, in part, unexpected, and provided awareness of limitations in the reconstruction technique, mainly related to conditions with large susceptibility differences between compartments.
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46

Rudd, Jonathan, Glenn Chubak, Hugo Larnier, Ronny Stolz, Markus Schiffler, Vyatcheslav Zakosarenko, Michael Schneider, Marco Schulz, and Matthias Meyer. "Commercial operation of a SQUID-based airborne magnetic gradiometer." Leading Edge 41, no. 7 (July 2022): 486–92. http://dx.doi.org/10.1190/tle41070486.1.

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Gradient measurement of the magnetic field vector, especially full-tensor magnetic gradiometers (FTMGs), provides various advantages over gradient components derived from measurements of the total magnetic intensity (TMI). These advantages include higher spatial resolution, directional information, and thus more detailed anomaly delineation and a significantly better-constrained solution space for magnetic inversion and interpretation. However, the airborne application of FTMG instruments requires exceptionally high sensor resolution and low levels of motion noise to maximize these advantages and to achieve high exploration depth. Superconducting quantum interference detectors (SQUIDs) are an effective option for FTMG sensors, now available commercially in the system discussed herein. This SQUID sensor system comprises intrinsic planar-type gradiometers that produce data with sufficiently low noise for use on an airborne platform. The evolution and advancement of the system and its predecessor over the past two decades has produced a robust commercial system that produces high-quality full-tensor data sets from a helicopter-towed-bird implementation. Because the SQUID sensors measure directionally sensitive data, the processing of the acquired data is significantly more challenging than for TMI sensors. Noise induced by the motion of the bird during flight, especially rotational noise, must be monitored and compensated. The introduction of a more robust and aerodynamic bird has significantly reduced the noise of the system. This noise reduction translates into greater sensitivity and accuracy and, thus, heightened confidence in the use of the survey data sets. While much of the early use of the system has been in diamondiferous kimberlite exploration, the system has successfully flown surveys in mineral exploration for a variety of targets, including gold, nickel, and iron ore. These data sets provide greater confidence in the geologic interpretation across the survey areas. Other applications for FTMG surveying include infrastructure mapping, unexploded ordnance detection, and compensation of electromagnetic data sets in marine environments.
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47

Resende, Daniel, Camila Dornelas, Maria I. B. Tavares, Lucio Cabral, Luis Simeoni, and Ailton Gomes. "Preparation of Modified Montmorillonite with Benzethonium and Benzalconium Chloride for Nanocomposites Preparation." Chemistry & Chemical Technology 3, no. 4 (December 15, 2009): 291–94. http://dx.doi.org/10.23939/chcht03.04.291.

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Modified clays were intercalated with benzethonium chloride and benzalkonium chloride by exchanging the sodium ions. The organoclays obtained were characterized by X-ray diffraction (XRD); thermogravimetric analysis (TGA) and low field nuclear magnetic resonance (NMR), through proton spin-lattice relaxation time measurements (T1H). From the characterization data, the formation of organically modified clays was confirmed. These products can probably be used to prepare PVC nanocomposites with superior processing characteristics due to better chemical structure of clay surfactants.
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48

Rodriguez, A. F. R., R. F. Lacerda, L. E. Maggi, Hory Mohammadpour, Mohammad Niyaifar, Shahrokh Niyaifar, Judes G. Santos, and M. A. Morales. "Initial Dynamic Susceptibility of Maghemite Nanoparticles Dispersed in Surface-Treated Polymeric Template." Journal of Nanoscience and Nanotechnology 21, no. 11 (November 1, 2021): 5694–97. http://dx.doi.org/10.1166/jnn.2021.19484.

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Magnetic nanocomposites based on maghemite nanoparticles supported (ex situ route) on styrene- divinilbenzene (Sty-DVB) copolymer templates were produced and characterized for their structure and morphology. The as-produced nanocomposites were further chemically-treated with different oxidant agents and surface-coated with stearic acid. X-ray diffraction and transmission electron microscopy data show that the incorporated nanoparticles are preserved despite the aggressive chemical treatments employed. From the dynamical susceptibility measurements performed on the nanocomposites, the values of the saturation magnetization (76 emu/g) and the effective magnetic anisotropy (1.7 × 104 J/m3) were obtained, in excellent agreement with the values reported in the literature for maghemite. This finding strongly supports the preservation of the magnetic properties of the supported nanosized maghemite throughout the entire samples’ processing.
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Vincent, T. L., P. P. Khargonekar, and F. L. Terry. "An Extended Kalman filtering-based method of processing reflectometry data for fast in-situ etch rate measurements." IEEE Transactions on Semiconductor Manufacturing 10, no. 1 (February 1997): 42–51. http://dx.doi.org/10.1109/66.554482.

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50

Lestari, Septi edang, Astra Yunita, Riskia Abdul Rahman, Refrizon, and Nanang Sugianto. "Application of magnetic Method on Mapping the Geothermal Sources at Air Putih, Lebong, Bengkulu." Newton-Maxwell Journal of Physics 3, no. 2 (October 31, 2022): 71–76. http://dx.doi.org/10.33369/nmj.v3i2.23125.

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Measurements have been made using the geomagnetic method in the Air Putih Tourism Area, Tambang Sawah Village, Pinang Belayar District, Lebong Regency with an area of 2000 m x 2500. Data collection was carried out using a Proton Procession Magnetometer (PPM) model G-856, which is a device with a proton sensor. which works based on the precess of the proton nucleus due to changes in the surrounding magnetic field and is equipped with other technical equipment, such as portable GPS (Global positioning system), types of navigation (maps of survey areas), such as talkies, umbrellas, pens, and recorded data. can be observed.. This research serves to map the potenTial for geothermal (geothermal), because this method is one of the geophysical methods that has advanTages in finding geothermal sources.Data processing is carried out using only Microsoft excel which can only plot magnetic anomalies and interpret qualitatively into initial research. To get the total animali, correction of IGRF (International Geomagnetics Reference Field) and correction of Daily Magnetic Value (diurnal). The results of this measurement obtained a magnetic field anomaly graph. This graph shows the high magnetic susceptibility value is found at poinT 43 which is suspected to be an area of economic value rock minerals and is in fracture zones and rocks with low susceptibility values are found at point 29 which can be suspected as a source area. hot water (hydrothermal). Keywords :Geomagnetic, Anomaly, and Hydothermal
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