Inclusions Of Different Sizes Research Articles

Thermo-Mechano-Chemical Processing of Printed Circuit Boards for Organic Fraction Removal

Printed circuit boards (PCBs) are the main components of e-waste. In order to reduce the negative impact of waste PCBs on human health and the environment, they must be properly disposed of. A new method is demonstrated for recycling waste PCBs. It is referred to as the high-temperature thermo-mechano-chemical gasification (TMCG) of PCBs by the detonation-born gasification agent (GA), which is a blend of H2O and CO2 heated to a temperature above 2000 °C. The GA is produced in a pulsed detonation gun (PDG) operating on a near-stoichiometric methane–oxygen mixture. The PDG operates in a pulsed mode producing pulsed supersonic jets of GA and pulsed shock waves possessing a huge destructive power. When the PDG is attached to a compact flow reactor filled with waste PCBs, the PCBs are subject to the intense thermo-mechano-chemical action of both strong shock waves and high-temperature supersonic jets of GA in powerful vortical structures established in the flow reactor. The shock waves grind waste PCBs into fine particles, which undergo repeated involvement and gasification in the high-temperature vortical structures of the GA. Demonstration experiments show full (above 98%) gasification of the 1 kg batch of organic matter in a setup operation time of less than 350 s. The gaseous products of PCB gasification are mainly composed of CO2, CO, H2, N2, and CH4, with the share of flammable gas components reaching about 45 vol%. The solid residues appear in the form of fine powder with visible metal inclusions of different sizes. All particles in the powder freed from the visible metal inclusions possess a size less than 300–400 μm, including a large fraction of sizes less than 100 μm. The powder contains Sn, Pb, Cu, Ni, Fe, In, Cd, Zn, Ca, Si, Al, Ti, Ni, and Cl. Among these substances, Sn (10–20 wt%), Pb (5–10 wt%), and Cu (up to 1.5 wt%) are detected in the maximum amounts. In the powder submitted for analysis, precious elements Ag, Au, and Pt are not detected. Some solid mass (about 20 wt% of the processed PCBs) is removed from the flow reactor with the escaping gas and is partly (about 10 wt%) trapped by the cyclones in the exhaust cleaning system. Metal inclusions of all visible sizes accumulate only in the flow reactor and are not detected in powder samples extracted from the cyclones. The gasification degree of the solid residues extracted from the cyclones ranges from 76 to 91 wt%, i.e., they are gasified only partly. This problem will be eliminated in future work.

Allotropic Ga2Se3/GaSe nanostructures grown by van der Waals epitaxy: narrow exciton lines and single-photon emission.

The ability to emit narrow exciton lines, preferably with a clearly defined polarization, is one of the key conditions for the use of nanostructures based on III-VI monochalcogenides and other layered crystals in quantum technology to create non-classical light. Currently, the main method of their formation is exfoliation followed by strain and defect engineering. A factor limiting the use of epitaxy is the presence of different phases in the grown films. In this work, we show that control over their formation makes it possible to create structures with the desired properties. We propose Ga2Se3/GaSe nanostructures grown by van der Waals epitaxy with a high VI/III flux ratio as a source of narrow exciton lines. Actually, these nanostructures are a combination of allotropes: GaSe and Ga2Se3, consisting of the same atoms in different arrangements. The energy positions of the narrow lines are determined by the quantum confinement in Ga2Se3 inclusions of different sizes in the GaSe matrix, similar to quantum dots, and their linear polarization is due to the ordering of Ga vacancies in a certain crystalline direction in Ga2Se3. Such nanostructures exhibit single-photon emission with second-order correlation function g(2)(0) ∼ 0.10 at 10 K that makes them promising for quantum technologies.

Multi-scale and multi-modal imaging study of mantle xenoliths and petrological implications

Abstract The accurate textural characterization of mantle xenoliths is one of the fundamental steps to understanding the main processes occurring in the upper mantle, such as sub-solidus recrystallization, magmatic crystallization, and metasomatism. Texture, composition, and mineralogy reflect the temperature, pressure, stress conditions, melting, and/or contamination events undergone before and during the entrapment in the host magma. For these reasons, characterizing the three-dimensional (3D) texture of silicate, oxide, sulfide, and glass phases has great importance in the study of mantle xenoliths. We performed a multi-scale and multi-modal 3D textural analysis based on X-ray computed microtomography (µ-CT) data of three mantle xenoliths from different geodynamic settings (i.e., mobile belt zone, pericraton, oceanic hotspot). The samples were selected to represent different, variably complex internal structures composed of grains of different phases, fractures, voids, and fluid inclusions of different sizes. We used an approach structured in increasing steps of spatial and contrast resolution, starting with in-house X-ray µ-CT imaging (spatial resolution from 30 µm down to 6.25 µm) and moving to high-resolution synchrotron X-ray µ-CT at the micrometer scale. We performed a 3D characterization of mantle xenoliths, comparing the results with the analysis of conventional 2D images (thin sections) obtained by optical microscopy and simulating the random sectioning of several thin sections to estimate the probability of correct modal classification. The 3D models allow the extraction of textural information that cannot be quantified solely from thin sections: spinel layering, distribution of silicic glass, and related vesicles. Moreover, high-density volumes identified as sulfides were detected in two xenoliths, showing no relation with the spinel layering in one case and a preferential concentration along fractures in the other. Given the variety of textures and mineral assemblages of mantle xenoliths worldwide, the results are used to suggest experimental and analytical protocols for the characterization of these materials.

Simulation of Fluid Flow and Inclusion Removal in Five-Flow T-Type Tundishes with Porous Baffle Walls

To solve the instability of liquid steel in the continuous casting process and the inconsistent flaw detection of heavy rail steel, steel flow control was studied numerically in a tundish with a porous baffle wall by using the fluid dynamics software Fluent. The opening plan of the baffle wall was improved through orthogonal optimization of the design of the holes in the porous baffle wall. The test condition was set to a left inclination angle of α1 = 22°, a right inclination angle of α2 = 48°, an upward elevation angle of β = 30°, and an aperture of d = 70 mm. The simulation results of the optimization scheme showed that the uniformity of the flow and temperature fields had been significantly improved, and the flow in each strand became consistent. The maximum temperature difference was 21 K in the tundish, and the maximum temperature difference of three outlets was only 1.7 K. Dead zone volume was reduced by 10.0% compared to the original tundish, and plug flow volume was increased by 14.2%. Comparing the removal efficiency of Al2O3 inclusions of different size, the results showed that the removal efficiency of 10 μm and 30 μm smaller inclusions was above 87%. The removal rate of ≥50 μm larger inclusions also remained about 95%.

Detection Limits of Tetrapolar Impedance Sensors for Tissue Differentiation.

Cancer recurrence is an important issue in bladder tumor resections, because tissue cannot generously be removed from the thin bladder wall without impacting its functionality. Electrical impedance measurements during an operation aim to support the surgeon in making the decision which tissue areas to preserve, because physiological changes in tissue due to cancerous mutations can be detected by their altered electrical characteristics. This work investigates the detection limits of tetrapolar sensors when the impedance of heterogeneous tissue is measured. To do this, a finite element analysis is carried out where the sensors are placed on a dielectric medium with inclusions of different sizes, conductivity, and locations relative to the sensor. It is shown that a sensor with four electrodes in a square performs poorly in comparison to a sensor where the electrodes are symmetrically shaped as rings around one center electrode. This is mainly due to its enlarged regions of negative sensitivity. Based on the results, a third, optimized sensor geometry is proposed that shows superior performance to the other sensors in terms of geometry factor, sensitivities, and tumor detection. In simulation, it can reliably detect tumors with only half the radius of the sensor surface. Smaller tumor fractions cannot be detected by either sensor.

Effects of inclusions on the fatigue life of SNCM439 steel in high-pressure hydrogen gas

Four heats of commercially available JIS SNCM439 steel are prepared, and fatigue tests are conducted in air and hydrogen gas. The materials evaluated are all martensitic steel with a tensile strength of 900 MPa or less and contain nonmetallic inclusions of different sizes. A decrease in the fatigue limit is observed in the specimens with large nonmetallic inclusions, but the fatigue limit in air is approximately equal to the fatigue strength at 300,000 cycles in hydrogen. However, in the finite life region, the fatigue life in hydrogen significantly decreases owing to the presence of large nonmetallic inclusions. It was observed that hydrogen considerably affects the fatigue life even at low stress amplitudes close to the fatigue limit. This effect is considered to be dependent on the size of the initial crack originating from the nonmetallic inclusions; large nonmetallic inclusions accelerate the hydrogen-induced fatigue crack growth rate.

MARBLE MÉLANGE: COMPOSITION VARIATIONS AND FORMATION MECHANISMS

The Olkhon terrane in the Western Baikal area accommodates four types of carbonate-silicate mixtures: injection (protrusion), metamorphic-boudinated, mingling, and tectonite marble mélange. The outcrops of injection mélange consist of a carbonate matrix with inclusions of native silicic rocks found in the immediate vicinities, commonly cover large areas and lack any distinct linearity in the map view. Mélange of the metamorphic boudinage type comprises diopsidite and tremilote-diopsidite fragments in a dolomitic or calcite-dolomitic matrix. Its origin is apparently due to tectonism and related metamorphism of quartz sandstones in Neoproterozoic strata on the passive margin of the Siberian craton. Mingling mélange appears as calcite marble or carbonate-silicate (calciphyre) veins with metadolerite and granite inclusions of different sizes. The veins formed by intrusion of carbonate and silicate melt batches and subsequent fragmentation of silicate rocks that crystallized earlier. Marble tectonites localized in narrow zones record the late phase of ductile marble injection.

Heat treatment effect on corrosion resistance and mechanical properties of EP718 precipitation-hardened nickel-based alloy

The paper investigates the effect of heat treatment modes on the corrosion resistance and strength properties of the EP718 precipitation-hardened nickel-based alloy originally developed for the aircraft industry and currently used in the oil and gas industry. The effect of the annealing temperature (980–1130 °C), holding time (1–2 h) and the time of intermediate and final aging (4–20 h) at 780 °C and 650 °C was studied. It was found that EP718 alloy strength and corrosion properties are determined by the hardening temperature. Highest strength properties are achieved at a hardening temperature of 980 °C (yield strength σy = 950 MPa) due to a higher grain score equal to 3.5 and the presence of inclusions of different size. However, in this case corrosion rate reaches V = 5.88 g/(m2·h). The temperature of 1130 °C ensures the best corrosion performance (V = 2.04 g/(m2·h)) due to the dissolution of undesirable phases (volume fraction of non-metallic inclusions is 0.47 %), but strength performance is reduced (σy = 756 MPa) in this case as a result of the lower grain score – 2.7. Aging mode consisting of an intermediate aging stage with holding at t = 780 °C for 5 h and a final stage at 650 °C for 16 h with air cooling ensures maximum hardening, which is expressed in an increase in hardness to 37.5–38.5 HRC. Electrochemical studies demonstrated that an increase in the aging time leads to a decrease in the stability of the passive state.

Котки різних конструкцій. Інженерний аналіз

Comparative field tests of similar in design ring-spur and gear-spur rollers for soil rolling provide their developers and users with information on the understanding of the design and technological features. The Goal of research – engineering analysis of structures of ring-spur and gear-spur rollers according to the criteria of weight, shape of working surfaces, soil pressure, completeness of compaction, penetrating ability in the range of depth of pre-sowing and surface tillage. Methods and Materials. Engineering analysis involved the study of three types of rollers. The research hypothesis assumed that the combination of weight characteristics of rollers and their geometric shapes of working surfaces in contact with the soil, in statics will provide the inherent properties of each cat (the first stage of research), which will potentially focus on choosing the most acceptable criteria for comparing functional features of rollers. necessary for field research in dynamics (the second stage of research). According to the criteria of static research were selected: penetrating ability (1); soil pressure (2); completeness of compaction of the area (3); direction of clamping forces (4); features of working surfaces (5); the nature of the mounting of solid disks on the shaft (6). Methodologically, the first three criteria required special adaptations (capacities) with the ability to change the height of the soil layer in the range of depths of pre-sowing and sowing tillage. Other criteria were supposed to be carried out by organoleptic evaluation. The study was supposed to be carried out on soil characteristic of the Forest-Steppe zone and homogeneous in fractional composition, to exclude the influence of soil inclusions of different sizes. Evaluation of soil characteristics was performed by thermostatic-weight method, according to the generally accepted method of "cutting ring" [Kaczynski, 1947] with a cylinder volume of 100 cm3. To determine the area of one elementary working surface of the annular disk, the application of a marking grid on its imprint on the surface left in the soil layers hmin, hmid, hmax was used. When determining the pressure on the soil, depending on the height of the treated layer, the marking grid was superimposed on the imprint of several areas of elementary working surfaces, which were fixed on the chord of immersion in the soil of the annular segment. Statistical analysis of experimental data was performed by the method of analysis of variance according to [Dospekhov, 1985] and interpreted by standard computer programs Excel and graphs. Results. According to the physical characteristics (weight and geometric parameters) of the roller combines the proximity of the diameter of the disks, the width of the working surfaces on the edge of the generator, the presence of spurs. The difference lies in the dimensional characteristics that fall on the width of the grip, the presence of aggressive protruding shapes (teeth) in the gear-spur structure. Each roller has an individual layout of elementary work surfaces. This allowed the conditional marking of rollers as "classic", "modernized" and "specialized". The working surfaces of the classic and specialized rollers provide vertical and lateral action of the clamping forces, while the modernized forms them in the vertical direction. These forces for each of the rollers are derived from the orientation of the working surfaces of different configurations (flat narrow, flat wide; a combination of point-focused with trapezoidal). In addition, work surfaces can have a one- or two-level sequence of contact with the soil at a variable depth. It is established that the nature of the attachment of adjacent disks on the shaft can be rigid or movable. Definitions of concepts and their estimation on indicators of pressure, completeness of consolidation, penetrating ability are resulted. Conclusions. According to the indicators of engineering analysis, each of the three rollers is predicted to have its inherent dominant feature for the most effective use in milling, pre-sowing and post-sowing tillage operations. It is determined that the most acceptable criteria for further research in the dynamics of variable speed should be the intensity of crushing lumps, the degree of soil compaction, the intensity of soil compaction, sticking of the working surface of the roller in high humidity, self-cleaning ability. The criteria of further research in dynamics are determined.

Shock‐thermal history of the Agoudal (IIAB) iron meteorite from microstructural studies

AbstractThe Agoudal IIAB iron meteorite exhibits only kamacite grains (~6 mm across) without any taenite. The kamacite is homogeneously enriched with numerous rhabdite inclusions of different size, shape, and composition. In some kamacite domains, this appears frosty due to micron‐scale rhabdite inclusions (~5 to 100 μm) of moderate to high Ni content (~26 to 40 wt%). In addition, all the kamacite grains in matrix are marked with a prominent linear crack formed during an atmospheric break‐up event and subsequently oxidized. This feature, also defined by trails of lowest Ni‐bearing (mean Ni: 23 wt%) mm‐scale rhabdite plates (fractured and oxidized) could be a trace of a pre‐existing γ–α interface. Agoudal experienced a very slow rate of primary cooling ~4 °C Ma−1 estimated from the binary plots of true rhabdite width against corresponding Ni wt% and the computed cooling rate curves after Randich and Goldstein (1978). Chemically, Agoudal iron (Ga: 54 ppm; Ge: 140 ppm; Ir: 0.03 ppm) resembles the Ainsworth iron, the coarsest octahedrite of the IIAB group. Agoudal contains multiple sets of Neumann bands that are formed in space and time at different scales and densities due to multiple impacts with shock magnitude up to 130 kb. Signatures of recrystallization due to postshock low temperature mild reheating at about 400 °C are also locally present.

Influence of silver inclusions on the mechanical behavior of Cu-Ag nanocomposite during nanoindentation: Molecular dynamics study

In this work, we study the effect of silver inclusions on the mechanical behavior of Cu-Ag nanocomposites during nanoindentation using Molecular Dynamics Simulations. Pure Cu and Cu matrices containing Ag inclusions of different sizes, located at various depths under the surface, are investigated.The results of simulations show that the presence of silver inclusion influences the strength of the material. Indeed, the hardness of Cu substrate containing an Ag inclusion is lower than that of pure Cu. In addition, for a given inclusion radius, the hardness decreases with decreasing inclusion depth beneath the indenter. Furthermore, our results also showed that, at a fixed inclusion depth, hardness increases as the inclusion radius decreases and the maximum hardness value is obtained for an inclusion radius and depth of 17.5 Å and 60 Å, respectively.

Random distribution of polydisperse ellipsoidal inclusions and homogenization estimates for porous elastic materials

This work proposes an extension of the well-known random sequential adsorption (RSA) method in the context of non-overlapping random mono- and polydisperse ellipsoidal inclusions. The algorithm is general and can deal with inclusions of different size, shape and orientation with or without periodic geometrical constraints. Specifically, polydisperse inclusions, which can be in terms of different size, shape, orientation or even material properties, allow for larger volume fractions without the need of additional changes in the main algorithm. Unit-cell computations are performed by using either the fast Fourier transformed-based numerical scheme (FFT) or the finite element method (FEM) to estimate the effective elastic properties of voided particulate microstructures. We observe that an isotropic overall response is very difficult to obtain for random distributions of spheroidal inclusions with high aspect ratio. In particular, a substantial increase (or decrease) of the aspect ratio of the voids leads to a markedly anisotropic response of the porous material, which is intrinsic of the RSA construction. The numerical estimates are probed by analytical Hashin-Shtrikman-Willis (HSW) estimates and bounds.

A comparative study of two constitutive models within an inverse approach to determine the spatial stiffness distribution in soft materials

A comparative study is presented to solve the inverse problem in elasticity for the shear modulus (stiffness) distribution utilizing two constitutive equations: (1) linear elasticity assuming small strain theory, and (2) finite elasticity with a hyperelastic neo-Hookean material model. Assuming that a material undergoes large deformations and material nonlinearity is assumed negligible, the inverse solution using (2) is anticipated to yield better results than (1). Given the fact that solving a linear elastic model is significantly faster than a nonlinear model and more robust numerically, we posed the following question: How accurately could we map the shear modulus distribution with a linear elastic model using small strain theory for a specimen undergoing large deformations? To this end, experimental displacement data of a silicone composite sample containing two stiff inclusions of different sizes under uniaxial displacement controlled extension were acquired using a digital image correlation system. The silicone based composite was modeled both as a linear elastic solid under infinitesimal strains and as a neo-Hookean hyperelastic solid that takes into account geometrically nonlinear finite deformations. We observed that the mapped shear modulus contrast, determined by solving an inverse problem, between inclusion and background was higher for the linear elastic model as compared to that of the hyperelastic one. A similar trend was observed for simulated experiments, where synthetically computed displacement data were produced and the inverse problem solved using both, the linear elastic model and the neo-Hookean material model. In addition, it was observed that the inverse problem solution was inclusion size-sensitive. Consequently, an 1-D model was introduced to broaden our understanding of this issue. This 1-D analysis revealed that by using a linear elastic approach, the overestimation of the shear modulus contrast between inclusion and background increases with the increase of external loads and target shear modulus contrast. Finally, this investigation provides valuable information on the validity of the assumption for utilizing linear elasticity in solving inverse problems for the spatial distribution of shear modulus associated with soft solids undergoing large deformations. Thus, this work could be of importance to characterize mechanical property variations of polymer based materials such as rubbers or in elasticity imaging of tissues for pathology.

Vaporization of water droplets with non-metallic inclusions of different sizes in a high-temperature gas

Experimental research on mechanisms of vapor production by boiling and evaporation was carried out on heterogeneous droplets of water containing graphite particles of different sizes and concentrations, heated by high-temperature environment (up to about 1373 K). Different steps have been observed, such as free surface evaporation of the droplet, bubbles boiling at the solid inclusion/liquid interface, the explosive disintegration of a drop into a cluster of small droplets and efficient evaporation of the produced smaller droplets. We proposed the conditions for the appearance of this explosive breakup of droplets. The present paper reports that the addition of small graphite particles into heterogeneous droplets can reduce their lifetimes by about 50% in this type of high-temperature environment. Moreover, this facilitated the explosive breakup of droplets, allowing intense vaporization. This behavior led us to make the hypothesis that an insulating layer of vapor appears at the outside droplet surface and at the interface between the solid inclusions and the droplet. Measurements on the explosive breakup of heterogeneous water droplets have allowed establishing an increase of the evaporation surface area by almost fifteen times, as compared to the initial surface of droplets. However, when using graphite suspension, the measured increase of the evaporation surface was not larger than threefold. The evaporation surface area during the explosive breakup of water-graphite suspensions was 5.4 smaller as compared to water without impurities. We reported on the reasons for the above differences. The results are useful for developing technologies of fire extinguishing by using water sprays containing non-metallic solids. Practical implementation of the explosive breakup of heterogeneous droplets can eventually permit extinguishing fire on larger areas with an identical water load.

Effect of hierarchically distributed nano-to microscale skutterudite inclusions on the lattice thermal conductivity of TiNiSn-based half-Heusler alloys

The goal of this work is an investigation of the reduction in lattice thermal conductivity of a Heusler alloy by introducing inclusions in a host matrix with initially high thermal conductivity. Using panoscopic hierarchical architecture approach and assuming Gamma-distribution for spherical inclusions of different size, a general expression is found for the effective lattice thermal conductivity of a two-phase thermoelectric material in “gray medium” approximation. As an application of this analytical expression, it is shown that the introduction of nano-sized skutterudite inclusions into the half-Heusler matrix can drastically reduce lattice thermal conductivity of the composite structure. Due to this effect, significantly higher ZT values can be achieved in the half-Heusler alloys at 300–700 K.

Calculating of the True Sizes and the Numbers of Spherical Inclusions in Metal

Observing inclusions on a polished plane, researchers do not see these inclusions directly, but only their cross sections. Meanwhile, the given size of a section can be obtained from the inclusions of different sizes. The true sizes of the inclusions and their quantities are hidden from the researchers. This paper proposes a new method for determining the size distribution of inclusions derived from the size distribution of their sections. The method based on mathematical statistics allows evaluating the true sizes and quantities of inclusions. A notable feature of the method is that it enables a researcher to derive the confidence sets for the distribution functions. A special technique for testing the method has been developed. Numerous tests have shown good adequacy of the method.

An improved multiscale Eulerian–Lagrangian method for simulation of atomization process

The physics of atomization process involve many spatial scales, generating a wide variety of liquid inclusions of different sizes with large density and viscosity ratios between liquid and gas phases. In order to correctly capture the dynamics of these phenomena, each scale needs to be resolved with an appropriate method to ensure the conservation of physical quantities (mass, momentum) as well as the jump conditions across the liquid-gas interface. To address these problems, an original multi-scale methodology has been developed. It consists of a core coupled Level-Set/Volume-of-Fluid method (CLSVOF) for accurate capture of primary atomization, an adaptive mesh refinement technique (oct-tree AMR) to dynamically optimize the structured Cartesian mesh and a particle tracking algorithm to capture droplet dynamics. An improved Eulerian–Lagrangian coupling has been developed to ensure a smooth transition between the Eulerian and the Lagrangian modelling frameworks in the zones where they reach their respective limits of validity. The overall procedure is tested on simplified numerical tests and validated on a realistic planar liquid sheet atomization case. Results highlight the ability of the present method to reproduce the whole atomization process, from large scale instabilities to small droplet dynamics, and allow a preliminary statistical spray analysis.

Identification of the geometry and elastic properties of rigid inclusions in thin plate

The presence of inclusions in thin-walled structural elements in the course of their operation under mechanical and thermal loads gives rise to the material damage. In publications on this subject, the problem of defect identification is considered in two directions – the location and shape of the defect or the physical properties of rigid inclusions are determined. The paper proposes a method for simultaneous determination of the location of rigid inclusions and their elastic properties (Young's modulus) in a thin plate. The mathematical model of a plate with the inclusion is built in the framework of the linear theory of elasticity. For quantization of unknown functions, the finite element method is used. The geometric inverse problem is formulated in the conditional-correct statement. The parameters of rigid inclusions are determined by minimizing the quality functional. Additional conditions are attached to the functional using the Lagrange multipliers. The results of the identification of one or several inclusions of different sizes by the proposed method are presented. In solving the problem for a plate with one rigid inclusion, the error of restoration of the inclusion location does not exceed 3 %, the error of determination of the Young's modulus of this inclusion – 2 %. The error of determination of the Young's modulus for a group of several rigid inclusions is in the range of 4–7 %. Comparative analysis of numerical experiment results shows that the proposed method allows identifying the location and properties of several rigid inclusions of various sizes. Solution of the problem of identifying the inclusions, determining their size and elastic properties allows more accurate estimation of the strength characteristics of elements and prediction of the service life of structures.

Investigation of quasi-stationary magnetic fields of corrosion currents of zinc-copper cells using giant magneto-impedance magnetometer

A scanning giant magneto-impedance (GMI) magnetometer has been used to measure small magnetic fields of corrosion currents in zinc-copper cells. In situ magnetic images of the copper plates with one or two small anode (zinc) inclusions of different sizes located at various distances at the sample surface have been obtained. To interpret the magnetic images of the corrosion currents a numerical simulation program has been developed. A good qualitative agreement between experimental and theoretical results proves that the scanning GMI magnetometry is a promising tool for in situ investigation of some of local corrosion processes.

Light scattering microscopy measurements of single nuclei compared with GPU-accelerated FDTD simulations

Single cell nuclei were investigated using two-dimensional angularly and spectrally resolved scattering microscopy. We show that even for a qualitative comparison of experimental and theoretical data, the standard Mie model of a homogeneous sphere proves to be insufficient. Hence, an accelerated finite-difference time-domain method using a graphics processor unit and domain decomposition was implemented to analyze the experimental scattering patterns. The measured cell nuclei were modeled as single spheres with randomly distributed spherical inclusions of different size and refractive index representing the nucleoli and clumps of chromatin. Taking into account the nuclear heterogeneity of a large number of inclusions yields a qualitative agreement between experimental and theoretical spectra and illustrates the impact of the nuclear micro- and nanostructure on the scattering patterns.