Volumetric Magnetic Susceptibility Research Articles

Comparison of Areal and Profile Distribution of Magnetic Susceptibility in Steppe Soils of the Russian Plain

A comparative analysis of areal and profile measurements of magnetic susceptibility was carried out on the plots pf 100 m2 in order to improve methods of surface soil sounding for mapping purposes and for identification of anomalies associated with anthropogenic pollution or disturbance of the surface soil layer. Two sites with Haplic Chernozems and one site with Haplic Kastanozem (Endosalic, Cambic) were studied. Additionally, a catena on the Yergeni Upland with different landscape positions (eluvial, transeluvial, transeluvial–accumulative) was studied. A comparison of the areal and profile magnetic susceptibility measured to a depth of 30 cm showed a direct correlation (R2 = 0.7). The areal survey was found to correctly determine the volumetric magnetic susceptibility ({{varkappa }_{{text{s}}}}) to a depth of 30 cm. The {{varkappa }_{{text{s}}}} variation at sites with different types of soils reflects soil–climatic zonality and spatial lithological heterogeneity expressed in different textures and mineralogical compositions of the upper (0–30 cm) soil layer within the test area of 10 × 10 m. The areal magnetic susceptibility of soils can be an important additional indicator capable of reflecting the features of soil-forming, lithological, and geochemical processes occurring in the upper soil layer. The {{varkappa }_{{text{s}}}} variation at sites in different landscape positions is due to the development of sheet erosion and changes in the direction of iron oxidogenesis depending on the position of the soil profile in the relief. The set of areal and profile magnetic susceptibility measurements can be used to study soil inhomogeneities caused by anthropogenic, paleocryogenic, geomorphological, and lithogenic factors. In particular, this approach can be applied to the study of polluted soils and monitoring of agricultural lands.

Comparison of Areal and Profile Distribution of Magnetic Susceptibility in Steppe Soils of the Russian Plain

A comparative analysis of areal and profile measurements of magnetic susceptibility was carried out in order to improve methods of surface sensing of the earth, as well as to take into account small-scale mapping of soils and the identification of anomalies associated with anthropogenic pollution or violation of the surface layer of soils. Two sites with Haplic Chernozems and one Haplic Kastanozems (Endosalic, Cambic) were studied. Additionally, a catena was studied on the territory of the Ergeninsky upland with the inclusion of sites in various positions of the landscape (eluvial, transeluvial, transeluvial-accumulative). The comparison of the areal and profile magnetic susceptibility measured to a depth of 30 cm showed a direct correlation (R2 = 0.7). It was found that the areal type of survey correctly captures the volumetric magnetic susceptibility (\({{\varkappa }_{{\text{s}}}}\)) to a depth of 30 cm. The variation of \({{\varkappa }_{{\text{s}}}}\) at sites with different types of soils reflects soil-climatic zonality and spatial lithological heterogeneity, expressed in different granulometric and mineralogical composition of the 0–30 cm layer on an area of 10 × 10 m. The areal magnetic susceptibility of soils can be an important additional indicator capable of reflecting the features of soil-forming, lithological and landscape geochemical processes occurring in the upper soil layer. Variation of \({{\varkappa }_{{\text{s}}}}\) at sites in different positions of the landscape occurs under the influence of planar flushing and a change in the direction of iron oxidogenesis processes depending on the position of the soil profile in the relief. The complex of measurements of areal and profile magnetic susceptibility can be used to study soil inhomogeneities caused by anthropogenic, paleocryogenic, geomorphological and lithogenic factors. Such an approach can be widely applied to the study of polluted soils and monitoring of agricultural land.

Геоинформационное картографирование эколого-магнитного состояния почв г. Краснокамска

The article is devoted to geoinformation mapping of the ecological and magnetic state of soils in the city of Krasnokamsk. The study included point determinations of the volumetric magnetic susceptibility of soils and the concentration of heavy metals, followed by mathematical-cartographic modeling of the results obtained. Mapping the magnetic susceptibility of soils makes it possible to form areas of the ecological and magnetic state of soils, along which samples are taken for the determination of heavy metals. Thus, the sample size of soil samples for heavy metal studies is reduced without a significant decrease in the representativeness of the final results, which determines the relevance of the studies performed. The purpose of the research is geoinformation mapping of the ecological and magnetic state of soils in the central part of the city of Krasnokamsk. The boundaries of research from the south are limited by the industrial zone of the city, which is mainly represented by pulp and paper industry enterprises. In the eastern part of the survey area, Zakamskaya CHPP-5 and a machine-building plant are located. The soil cover of Krasnokamsk is represented by urbanozems and technogenic surface formations. The total number of magnetic susceptibility measurement points was 77, and heavy metals were determined in 10 samples. During processing spatial data, the methods of mathematical-cartographic modeling, spatial overlay and binary classification were used. The interpolation was performed by the geostatistical method ordinary kriging using the Spatial Analyst tool of the ArcGIS 10.8 program. The creation of the Web GIS “Geoinformation system of magnetic susceptibility and heavy metals in the soils of Krasnokamsk” was performed on the basis of QGIS open geotechnologies using the qgis2web tool, the VS Code code editor. The Web GIS is hosted on the free GitHub platform. Based on the results of mapping, soil contamination with nickel and copper was established. The total area of pollution was 0.55 km2.

The Influence of Magnetic Minerals on Induced Polarization Measurements in Sedimentary Rocks

AbstractInduced polarization (IP) measurements in porous sedimentary rocks are modeled in terms of pore geometrical descriptors (PGD). Using an extensive data set composed of 241 sandstone, carbonate, and arenite samples, we identified a stronger relationship between IP parameters and volumetric magnetic susceptibility versus IP parameters and PGD. This finding suggests that even small concentrations of iron minerals in rocks typically thought to lack electron‐conducting minerals can significantly influence IP measurements. The combination of magnetic susceptibility with a pore geometrical descriptor term improves the empirical prediction of IP measurements relative to the use of pore geometrical descriptor terms alone. This suggests that small concentrations of iron minerals exert a strong control on the specific capacitance, a property that remains poorly understood. The lack of any relationship between magnetic susceptibility and the PGD confirms that the magnetic susceptibility provides additional information unrelated to PGD.

Particle-based characterization and classification to evaluate the behavior of iron ores in drum-type wet low-intensity magnetic separation

Magnetic separation is a versatile technique widely used in the mining industry. Drum-type wet low-intensity magnetic separation (WLIMS) represents the backbone of the iron ore upgrading circuits since the mid 19th century. However, it has been traditionally applied through guidelines that commonly disregard the ore properties and their interaction with the operating conditions to influence the final process selectivity. This work describes a three-stage methodology to achieve the comprehensive characterization and classification of an iron ore, seeking to recognize links between the ore properties and operating conditions, and their influence upon the process performance. This methodology integrates 1) laboratory testing, 2) particle-scale characterization of the ore and products from separation trials, and 3) data analysis to identify and categorize the particle attributes that control their behavior in a laboratory-scale magnetic separator. Dry sieving, Saturation Magnetization Analyzer (SATMAGAN) and Mineral Liberation Analysis (MLA) represent the basis to collect quantitative particle-level information for clustering the ore into classes of unique nature. The further determination of the volumetric magnetic susceptibility by particle class, together with the relative probability of particle capture, provides valuable insight on the ore magnetic behavior. The calculation of particle-classed partition coefficients resulted practical to assess the process selectivity in terms of particle attributes and operating conditions. The methodology proposes guidelines to comprehend the behavior of an ore from a particle-scale perspective. Moreover, the acquired data can be used for geometallurgical and process modeling, which represent promising forecasting tools to support decision-making in plants.

Awaruite, a new large nickel resource. Part 1: Physicochemical properties and their implication for mineral processing

Nickel is an important component of stainless steel and a wide range of applications which are critical for the transition to clean energies including electric vehicle batteries. Awaruite is a native nickel–iron alloy that has gained interest as a possible new economic source of nickel. In the last decades, there have been discoveries of awaruite, mostly with more significant amounts of nickel sulphides, that have demonstrated the potential for awaruite to contribute to the economics of a deposit. This study is focused on the very large Baptiste deposit in central British Columbia, Canada where awaruite is the primary nickel mineral. Most of published data on awaruite are focused on geology, and important fundamental physiochemical properties have still not been determined. These properties are fundamental for the set-up of a flowsheet that will enable its large-scale processing. The limited information available of this nickel–iron alloy can be complemented with the available information of a synthetic alloy with the same elemental composition. The synthetic awaruite alloy has demonstrated remarkable magnetic properties, and based on those properties, it was named permalloy. In this study, physicochemical properties of native and synthetic awaruite were measured including chemical composition, crystallographic structure, and magnetic properties. The native awaruite composition from the Baptiste deposit averages 77.3 % nickel, 21.0 % iron, 1.1 % cobalt and 0.6 % copper. Natural and synthetic awaruite have the same crystallographic characteristics and similar ferromagnetic behaviour. The measured initial volumetric magnetic susceptibility for native awaruite was 14.4 and the saturation magnetization was 750kA/m. Awaruite has the potential to be concentrated in a unique and valuable nickel concentrate of distinctive characteristics including its very high nickel content, which lowers both the downstream costs and the carbon intensity. Furthermore, the negligible content of sulphur and penalty trace elements, such as mercury, antimony, and arsenic in a potential awaruite concentrate, minimizes the costs of refining it. The physicochemical data in this study provides information to reliably set up a mineral processing flowsheet, which is discussed in this work.

Integrated petrographical and petrophysical studies of sandstones from the Araba Formation for reservoir characterization

The present study aims at an integration of both petrographic and petrophysical data of 45 sandstone samples collected from Araba Formation (Lower Paleozoic) for reservoir characterization. The studied Araba Formation is classified into three types of facies: (i) quartz arenite, (ii) sublithic quartz arenite, and (iii) calcareous quartz arenite. The mineralogical composition of the studied sandstone samples includes mainly quartz and detrital clays, some pyrite, and iron oxides as cement. The petrographic investigation of the studied Araba Formation reveals various diagenetic processes including compaction and pressure solution, cementation with iron oxides, carbonates, or clays. The porosity values for investigated samples range from 14.5 to 27.8% and permeability values from 2.4 mD to 8.4 D, the surface area per unit pore volume (Spor) from 0.011 to 17 µm−1, the formation factor from 6 to 13, and the dimensionless volumetric magnetic susceptibility from 13 10−6 to 126 10−6. The samples of facies (i) and (ii) are characterized by higher values of porosity and permeability. The samples of facies (iii) indicate increasing permeability with rising porosity. The relationship between permeability and formation factor reflects the effect of porosity changes. The specific surface Spor shows an inverse relationship to permeability. The petrophysical investigations provide relationships between permeability and other reservoir parameters such as porosity, formation factor, specific surface, and longitudinal and transverse relaxation time resulting from nuclear magnetic resonance (NMR) relaxometry. The permeability prediction model based on NMR data proves to be applicable for samples from facies (i) and (ii), whereas the predictive quality is considerably lower for facies (iii).

Картографирование магнитной восприимчивости почв г. Чайковский

The article presents the results of an assessment of the heterogeneity of the volumetric magnetic susceptibility of soils in the city of Chaikovsky, Perm Territory, based on the results of its spatial modeling. Determination of magnetic susceptibility makes it possible to estimate the concentration of technogenic magnetic particles in urban soils. Their sources in the atmosphere and soil cover of urbanized landscapes are emissions from vehicles, thermal power plants, and industrial enterprises. The non-stoichiometric technogenic magnetite-maghemite complex of minerals in urban soils has an abnormally high magnetic susceptibility and contains potentially dangerous chemical elements belonging to the heavy metals (HM) group in the composition of the crystal lattice of magnetic particles. Cartographic materials make it possible to assess the environmental risk for city residents, identify unfavorable areas and conduct a spatial analysis of the relationship between their location and pollution sources. The purpose of the research is spatial modeling of the magnetic susceptibility of soils in the city of Chaikovsky. The research area covers a section of the city with a total area of 22 km². Spatial modeling was carried out using geostatistical and deterministic methods based on 140 points. As a result of cross-validation, it was found that the most accurate interpolation method is “Ordinary Kriging” with the help of which the boundaries of the contaminated areas of the city of Chaikovsky are established. Within these boundaries, soil samples were taken, in which the content of nickel, copper, zinc, and lead was determined. According to the data obtained, areas with high magnetic susceptibility of soils have higher concentrations of heavy metals. To bring the research results to the administration and residents of the city, a Web GIS application has been developed, access to which is organized through the GitHub platform.

Application of magnetic susceptibility measurement for mapping and assessment of ecological quality in urban topsoils

The article presents the results of geostatistical mapping of the magnetic susceptibility of the urban top soil. Soil magnetometry is well suited for rapid monitoring of pollution in urban areas due to its high sensitivity, ease of measurement, rapidity, high reproducibility of analysis, and low cost. This method allows obtaining large datasets with high resolution. The purpose of the study: spatial modeling of magnetic susceptibility and ecological-geochemical assessment of the top soil of Kudymkar city. The research area covers a section of the city with a total area of 32 km². Spatial modeling was carried out by the geostatistical method based on 51 soil samples. The background magnetic susceptibility of the soils of the city is 3–4 times higher than the magnetic susceptibility of the soils of the non-contaminated regional background. Soils with high and very high magnetic susceptibility occupy more than 30 % of the city area. Anomalous zones of soil magnetic pollution or magnetic “hot spots” formed near industrial facilities, heating boilers, on roadside soils with heavy traffic. A scale for the volumetric magnetic susceptibility of soils was developed on the centile analysis of the data. Strongly magnetic soils contain elevated concentrations of Zn, Cu, and Ni. The concentrations and names of pollutant metals in urban soils depend on the techno-geochemical specialization of cities. It can be recommended that the Environmental Services of cities use measurements of the magnetic susceptibility to monitor the ecological and geochemical state of soils and identify areas of city soils contaminated with heavy metals.

Магнетизм корінних порід та магнітна сприйнятливість ґрунту

Information support of modern agriculture and ecology forms a demand for ever higher requirements for efficiency and density of the sampling network. This fact determines the spread of high-performance methods of soil research, among which are magnetometric ones. However, these methods have a number of limitations associated with the existence in soils of ferromagnets of non-pedogenic nature. The purpose of the study is to show the patterns of spatial and profile distribution of soils with high values of magnetic characteristics, inherited from parent rocks as a result of pedogenesis. The research used: determination of specific magnetic susceptibility using kappabridge KLY-2, determination of volumetric magnetic susceptibility with kappameter KT-5 and induction of magnetic field by proton magnetometer MP 203. The study was conducted at two objects located in the central part of the Ukrainian shield region. Studies have shown that soils developed on the weathering crust are characterized by certain features of their magnetic properties. First of all, it depends on the petromagnetic parameters of the source rocks. On magnetic rocks, the MS of soils is determined primarily by inherited magnetic minerals. The magnetic susceptibility of such soils has two maxima. The first is in the upper part of the profile, where it is determined by the sum of pedogenic and terrigenous magnets. The second is located in the lower part of the profile, which consists almost entirely of weathering products.

Liquid Crystalline Tactoidal Microphases in Ferrofluids: Spatial Positioning and Orientation by Magnetic Field Gradients

Summary Macroscopic manipulation of self-assembly in lyotropic systems, such as chiral nematic liquid crystals formed by cellulose nanocrystals, is kinetically hindered by the similarity between isotropic and anisotropic phases in composition and physical properties. By creating a significant difference in volumetric magnetic susceptibility between discrete liquid crystalline tactoids and continuous isotropic phases (based on the exclusion effects of tactoids on superparamagnetic doping nanoparticles), we achieved position and orientation control of liquid crystalline tactoids by magnetic field gradients as weak as several hundred gauss per centimeter, where the movement of tactoids is determined by competition between magnetic and gravitational acceleration fields. We also undertook a preliminary examination of the trapping of a liquid crystalline phase in the potential well of a quadrupole magnetic field. This method enabled us to control the phase separation rate and configuration, as well as the orientation of director fields in both tactoids and macroscopic ordered phases.

Mechanochemically Synthesised Coal-Based Magnetic Carbon Composites for Removing As(V) and Cd(II) from Aqueous Solutions.

The continued decrease in water quality requires new advances in the treatment of wastewater, including the preparation of novel, effective, environmentally friendly, and affordable sorbents of toxic pollutants. We introduce a simple non-conventional mechanochemical synthesis of magnetically responsive materials. Magnetic lignite and magnetic char were prepared by high-energy ball co-milling from either raw Slovak lignite or coal-based char together with a ferrofluid. The products were characterised by X-ray diffraction, electron microscopy, 57Fe Mössbauer spectroscopy, X-ray photoelectron spectroscopy (XPS), volumetric magnetic susceptibility, and low-temperature nitrogen adsorption, and both magnetic carbons were comparatively tested as potential sorbents of As(V) oxyanions and Cd(II) cations in aqueous solutions. The magnetic char was an excellent sorbent of As(V) oxyanions (Qm = 19.9 mg/g at pH 3.9), whereas the magnetic lignite was less effective. The different sorption properties towards arsenic anions may have been due to different oxidation states of iron on the surfaces of the two magnetic composites (determined by XPS), although the overall state of iron monitored by Mössbauer spectroscopy was similar for both samples. Both magnetic composites were effective sorbents for removing Cd(II) cations (Qm (magnetic lignite) = 70.4 mg/g at pH 6.5; Qm (magnetic char) = 58.8 mg/g at pH 6.8).

A new study of magnetic nanoparticle transport and quantifying magnetization analysis in fractured shale reservoir using numerical modeling

The application of nanoparticles has successfully attracted much attention due to the potential advantages of nanotechnology to lead to revolutionary changes in the oil and gas industry, such as nano-scale sensors, enhanced oil recovery and subsurface mapping. This paper will study the potential application of magnetic nanoparticles as contrast agents to enhance signals from well logging as well as improve reservoir and fracture characterization. Little work has been conducted to establish numerical models for investigating nanoparticle transport in reservoirs, and even less for unconventional reservoirs. Unlike conventional reservoirs, shale formations could contain four different pore systems: inorganic matter, organic matter dominated by hydrocarbon wettability, natural fractures and hydraulic fractures. These various pore media increase the difficulty to exactly describe the transport of nanoparticles along with aqueous phase. Concurrently, hydraulic fractures and the associated stimulated reservoir volume (SRV) from induced fractures need to be considered in hydraulically fractured reservoirs because of its significant assistance to well productivity.We have developed a mathematical model for simulating nanoparticle transport in shale reservoirs. The simulator includes various flow mechanisms from Darcy flow, Brownian diffusion of nanoparticles, gas diffusion and desorption, slippage flow, and capillary effects based on the extremely low permeability and micro- to nano-scale of the pores. Moreover, these mechanisms are separately applied to the sub-media of the reservoir due to the variation of media properties. Firstly, numerical applications including both two-dimensional micro model and macro model are presented, both models with organic matter randomly distributed within the matrix. Based on the integral finite difference and Newton–Raphson method, the distribution of water saturation and nanoparticle mass are calculated and graphically shown in different time steps. The main conclusion from these models is, as expected, nanoparticles can easily flow along with the aqueous phase into the fractures, but their transport into the shale matrix is quite limited, with even less transport shown into the organic matter of matrix. Secondly, a large reservoir model containing SRV is built to investigate the effect of magnetic nanoparticles on the volumetric magnetic susceptibility (VMS) of the reservoir. Based on the measured properties of synthesized magnetic carbon-coated iron-oxide nanoparticles, the distribution of the VMS is simulated and displayed in the numerical cases with and without magnetic nanoparticles. Besides, several different grids are chosen to display the varying trend of VMS along with time. The numerical results demonstrate that magnetic nanoparticles can effectively enlarge the VMS and the magnetization of reservoir, thus producing enhanced signals from well logging devices such as Nuclear Magnetic Resonance (NMR). This simulator can provide the benefits of both numerically simulating the transport and distribution of nanoparticles in hydraulically fractured shale formations and supplying helpful guidance for nanoparticles injection plans to enhance well logging signals and improve petrophysical evaluation. Furthermore, this model could also allow us to simulate the tracer transport flow in unconventional reservoirs.

Relevant magnetic and soil parameters as potential indicators of soil conservation status of Mediterranean agroecosystems

SUMMARY The main sources of magnetic minerals in soils unaffected by anthropogenic pollution are iron oxides and hydroxides derived from parent materials through soil formation processes. Soil magnetic minerals can be used as indicators of environmental factors including soil forming processes, degree of pedogenesis, weathering processes and biological activities. In this study measurements of magnetic susceptibility are used to detect the presence and the concentration of soil magnetic minerals in topsoil and bulk samples in a small cultivated field, which forms a hydrological unit that can be considered to be representative of the rainfed agroecosystems of Mediterranean mountain environments. Additionalmagneticstudiessuchasisothermalremanentmagnetization(IRM),anhysteretic remanent magnetization (ARM) and thermomagnetic measurements are used to identify and characterize the magnetic mineralogy of soil minerals. The objectives were to analyse the spatial variability of the magnetic parameters to assess whether topographic factors, soil redistribution processes, and soil properties such as soil texture, organic matter and carbonate contents analysed in this study, are related to the spatial distribution pattern of magnetic properties. The medians of mass specific magnetic susceptibility at low frequency (χlf )w ere 36.0 and 31.1 × 10 −8 m 3 kg −1 in bulk and topsoil samples respectively. High correlation coefficients were found between the χlf in topsoil and bulk core samples (r = 0.951, p < 0.01). Inaddition,volumetricmagneticsusceptibilitywasmeasuredinsituinthefield(κis)andvalues varied from 13.3 to 64.0 × 10 −5 SI. High correlation coefficients were found between χlf in topsoil measured in the laboratory and volumetric magnetic susceptibility field measurements (r = 0.894, p < 0.01). The results obtained from magnetic studies such as IRM, ARM and thermomagnetic measurements show the presence of magnetite, which is the predominant magnetic carrier, and hematite. The predominance of superparamagnetic minerals in upper soil layers suggests enrichment in pedogenic minerals. The finer soil particles, the organic matter content and the magnetic susceptibility values are statistically correlated and their spatial variability is related to similar physical processes. Runoff redistributes soil components including magnetic minerals and exports fine particles out the field. This research contributed tofurtherknowledgeontheapplicationofsoilmagneticpropertiestoderiveusefulinformation on soil processes in Mediterranean cultivated soils.

Hydraulic pressures generated in Magnetic Ionic Liquids by paramagnetic fluid/air interfaces inside of uniform tangential magnetic fields

HypothesisMagnetic Ionic Liquid (MILs), novel magnetic molecules that form “pure magnetic liquids,” will follow the Ferrohydrodynamic Bernoulli Relationship. Based on recent literature, the modeling of this fluid system is an open issue and potentially controversial. ExperimentsWe imposed uniform magnetic fields parallel to MIL/air interfaces where the capillary forces were negligible, the Quincke Problem. The size and location of the bulk fluid as well as the size and location of the fluid/air interface inside of the magnetic field were varied. MIL properties varied included the density, magnetic susceptibility, chemical structure, and magnetic element. FindingsUniform tangential magnetic fields pulled the MILs up counter to gravity. The forces per area were not a function of the volume, the surface area inside of the magnetic field, or the volume displacement. However, the presence of fluid/air interfaces was necessary for the phenomena. The Ferrohydrodynamic Bernoulli Relationship predicted the phenomena with the forces being directly related to the fluid’s volumetric magnetic susceptibility and the square of the magnetic field strength. [emim][FeCl4] generated the greatest hydraulic head (64-mm or 910Pa at 1.627Tesla). This work could aid in experimental design, when free surfaces are involved, and in the development of MIL applications.

A multi-sensor logger for rock cores: Methodology and preliminary results from the Matagami mining camp, Canada

Diamond drilling typically constitutes a major part of costs in advanced mineral exploration programs. This generates thousands of meters of rock cores during major exploration campaigns, but the cores are not currently utilized to their full potential. They could supply three-dimensional information on physical properties, geochemistry and mineralogy; such data could be used to model the geology or physical properties in 3D, characterize hydrothermal alteration, or provide chemo-stratigraphic constraints, for example. But measuring all the parameters one by one at high spatial resolution by traditional methods would be impractical due to cost or time considerations and, for some parameters, it would destroy the core (e.g. geochemistry).In this paper we describe a multi-sensor core logger and its use on rock cores from exploration diamond drill holes. This semi-automated system can measure near-simultaneously, non-destructively and at high spatial resolution, the following parameters: (1) volumetric magnetic susceptibility; (2) density using gamma-ray attenuation; (3) several chemical elements through energy-dispersive X-ray fluorescence spectrometry; and (4) visible/near infrared spectrometry, which allows numerous minerals to be detected and characterized. The logger also acquires a continuous image of the core using a line-scan camera, which allows the user to compare other properties with the visual aspect of the core and creates a complete virtual archive. The aim of this mostly methodological paper is to describe the logger as a whole and then each instrument or sensor separately, outlining the numerous tests that have been performed to assess and improve data quality. We also present preliminary results from the Matagami mining camp of Canada, a base metal district.

Magnetic susceptibility of iron in malaria-infected red blood cells

During intra-erythrocytic maturation, malaria parasites catabolize up to 80% of cellular haemoglobin. Haem is liberated inside the parasite and converted to haemozoin, preventing haem iron from participating in cell-damaging reactions. Several experimental techniques exploit the relatively large paramagnetic susceptibility of malaria-infected cells as a means of sorting cells or investigating haemoglobin degradation, but the source of the dramatic increase in cellular magnetic susceptibility during parasite growth has not been unequivocally determined. Plasmodium falciparum cultures were enriched using high-gradient magnetic fractionation columns and the magnetic susceptibility of cell contents was directly measured. The forms of haem iron in the erythrocytes were quantified spectroscopically. In the 3D7 laboratory strain, the parasites converted approximately 60% of host cell haemoglobin to haemozoin and this product was the primary source of the increase in cell magnetic susceptibility. Haemozoin iron was found to have a magnetic susceptibility of (11.0 ± 0.9) × 10 − 3 mL mol − 1 . The calculated volumetric magnetic susceptibility (SI units) of the magnetically enriched cells was (1.88 ± 0.60) × 10 − 6 relative to water while that of uninfected cells was not significantly different from water. Magnetic enrichment of parasitised cells can therefore be considered dependent primarily on the magnetic susceptibility of the parasitised cells.

Average heat transfer rates measured in two different temperature ranges for magnetic convection of horizontal water layer heated from below

The average heat transfer rates of gravitational and magnetic convection of water heated from below and cooled from above are measured for two cases of cold wall temperature θ c at 10 °C and 30 °C. The height of the cylindrical enclosure is 2 mm with 40 mm in diameter. The magnetic field is imposed in a vertical direction to increase or decrease 29% of the gravitational acceleration in a bore space of a super-conducting magnet of 10 T at the solenoid center. The group of data at θ c = 30 °C gives a better agreement with the classical heat transfer rate of Silveston than that at θ c = 10 °C. This is probably due to the almost constant value in the volumetric magnetic susceptibility of water at about 10 °C.

A novel microbubble construct for intracardiac or intravascular MR manometry: a theoretical study

It has been demonstrated that gas-filled microbubble contrast agents, based on their volume changes, can serve as pressure probes in an MR field. It was recently reported that such an MR-based pressure measurement with microbubbles at 1.5 T must make use of microbubbles that have a volumetric magnetic susceptibility difference with the blood of at least 34 ppm in SI units. In this work, we show through analytical approximations and numerical simulations that such a microbubble formulation can be achieved by coating typical lipid-shelled microbubbles with particles of high dipole moment. Through finite-element simulations we demonstrate that the effective volumetric magnetic susceptibility of a coated microbubble is dependent on the radius, the shell volume fraction and the magnetic susceptibility of the particulates on the shell. Our calculations suggest that a suitable microbubble formulation which will be MR-sensitive to small pressure changes at 1.5 T must be 2–3 µm in radius and be uniformly coated with single-domain magnetic nanoparticles, such as magnetite, at shell volume fractions below 5%.

Establishment and implications of a characterization method for magnetic nanoparticle using cell tracking velocimetry and magnetic susceptibility modified solutions

Magnetic micro and nanoparticles conjugated to affinity labels have become a significant, commercial reagent. It has been demonstrated that the performance of cell separation systems using magnetic labels is a function of the magnitude of the magnetic force that can be generated through labeling. This magnetic force is proportional to the number of magnetic particles bound to the cell, the magnetic energy gradient, and the particle-field interaction parameter. This particle-field interaction parameter, which is the product of the relative volumetric, magnetic susceptibility and the volume of the micro or nanoparticle, is a fundamental parameter which can be used to characterize the magnetic particles. An experimental technique is presented which measures the volumetric magnetic susceptibility of particles through the use of susceptibility modified solutions and an experimental instrument, Cell Tracking Velocimetry, CTV. Experimental studies were conducted on polystyrene microspheres alone and those bound to four different magnetic nanoparticles. The experimentally determined values of the magnetic susceptibility of the polystyrene microspheres are consistent with values found from literature. Consequently, magnetic susceptibility measurements of these polystyrene microspheres bound with the magnetic nanoparticles combined with particle size measurements using commercial dynamic light scattering instrument allowed estimates of the particle-field interaction parameter to be made for four commercial, magnetic nanoparticles. The value found for MACS beads is close to what is reported from an independent study. The values for MACS beads and Imag beads are found to agree with what is observed from experiments. Finally, an experimental demonstration of the impact that differences in this field interaction parameter has on the labeling of human lymphocytes is presented.