Distribution Of Inclusions Research Articles

Characteristics of Mineralization-Forming Fluid and Metallogenic Mechanism for the Mianhuakeng Uranium Deposit in South China: Constraints from In Situ Geochemical Signatures and Sulfur Isotopes of Syn-Mineralization Pyrite and Pitchblende

The Mianhuakeng deposit is the most representative granite-related hydrothermal vein-type uranium deposit in South China; however, the characteristics of the mineralization-forming fluid and metallogenic mechanism are still less constrained. To address the scientific problems above, we investigated the trace element chemistry and sulfur isotope compositions in syn-mineralization pyrite and pitchblende from the Mianhuakeng uranium deposit. The trace element chemistry shows that the mineralization in the Mianhuakeng deposit belongs to an intermediate-to-low temperature hydrothermal system, which is consistent with the homogenization temperature distribution of fluid inclusions. Redox-sensitive elements (such as Co and Se) in syn-mineralization pyrite suggest a reductive nature of the mineralization-forming fluids. The fractionation between light and heavy REE in pitchblende from the Mianhuakeng deposit is most similar to those from the Changjiang pluton. The pronounced negative Eu anomaly is coincident with mineralization-bearing granites. The δ34S values of syn-mineralization pyrite range from −10.2 to −1.4‰, which is higher than those values of pyrite from granites near the studied area and lower than the δ34S values of pyrite from diabase in the ore district. The REE signatures of pitchblende and sulfur isotope composition of syn-mineralization pyrite suggest that the major U source for the Mianhuakeng deposit is most likely the Changjiang pluton, probably accompanied by the incorporation of mantle-derived fluids. The circulations of CO2-rich hydrothermal fluids leached uranium from granite source rocks, especially from the Changjiang pluton. The change of physicochemical conditions of the mineralization-forming fluid resulted in the deposition of the uranium minerals in favorable structural traps to form the hydrothermal vein-type Mianhuakeng uranium deposit.

Oriented Magnetite Inclusions in Plagioclase: Implications for the Anisotropy of Magnetic Remanence

AbstractMicron to sub‐micron sized ferromagnetic inclusions in rock forming silicate minerals may give rise to particularly stable remanent magnetizations. When a population of inclusions have a preferred crystallographic or shape orientation in a rock, the recorded paleomagnetic direction and intensity may be biased by magnetic anisotropy. To better understand this effect, we investigated plagioclase grains from oceanic gabbro dredged from the Mid‐Atlantic Ridge at 11°–17°N. The plagioclase grains contain abundant needle and lath shaped magnetite inclusions aligned along specific directions of the plagioclase lattice. Electron back scatter diffraction and anisotropy of magnetic remanence measurements are used to correlate the orientation distribution of the magnetite inclusions in the host plagioclase that contains multiple twin types (Manebach, Carlsbad, Albite, and Pericline) with the bulk magnetic anisotropy of the inclusion‐host assembly. In non‐modified plagioclase, the anisotropy ellipsoid of magnetic remanence has oblate shapes that parallels the plagioclase (010) plane. It is suggested that recrystallization of magnetite inclusions during hydrothermal overprint shifts the relative abundance of the inclusions pertaining to the different orientation classes. We show that the maximum axis of the anisotropy ellipsoid of magnetic remanence parallels the plagioclase [001] direction, which in turn controls the recorded remanent magnetization direction. Our results are relevant for paleointensity and paleodirection determinations and for the interpretation of magnetic fabrics.

Characterization of the morphological evolution of MnS inclusions in free-cutting steel during heating

The size, morphology and distribution of MnS inclusions in the sulfur bearing free-cutting steel are the key factors to determine the performance of the free-cutting steel. It is thus important to accurately characterize and control the morphology of the MnS inclusions in the steel. The morphology of MnS inclusions are complex during rolling due to their good plasticity. Additionally, the morphology of the MnS inclusions would change during heating due to the decomposition and mass transfer of the Mn and S in the steel matrix. The traditional metallographic for characterizing the MnS inclusions on the cross-sections only reveal the local characteristics of the inclusions and results in misunderstanding of the real morphologies. In this study, the three-dimensional (3D) morphology of the MnS inclusions in the sulfur bearing free-cutting steels is characterized by using the X-ray Micro-CT in the beamline of BL13W1 at Shanghai Synchrotron Radiation Facility (SSRF). The stereology and morphological evolution of the MnS inclusion during heating are characterized and analyzed based the 3D observation. The number of MnS inclusions increased more than twice, the length of the inclusion with sizes less than 9 μm increased from 25.79% to 71.28%. The anisotropy index was reduce from 2.30 to 1.04 due to the spheroidization of the MnS inclusions during heating. The mechanism of the morphological evolution of the MnS inclusions is discussed on basis of the local chemical potential of the MnS caused by the variation of the curvature on the surface of the inclusions.

Composition of Organosilicate Coatings High-Temperature Breakdown Products and Their Distribution in the Weld

The construction assembly and the repair of steel constructions painted with protective coatings are often carried out using arc welding. During the welding process, the coating in the weld zone is degrading. The protective coatings breakdown products are involved in the pore and non-metallic inclusion formation in the weld, the composition and distribution study of which makes it possible to analyze the reactions occurring during the welding. In this study, welding beads were deposited on the coated sheet surface by MAG welding. The distribution of inclusions (the average diameter and the relative content) along with the porosity in different bead zones were investigated by optical and scanning electron microscopy and digital image processing, and the chemical composition of inclusions was determined using energy-dispersive X-ray spectroscopy. The amount of diffusible hydrogen in the deposited metal was estimated with the vacuum method. In this work, four organosilicate coatings grades, differing in their purpose and heat resistance, were used, and their effect on the weld was studied.

Self-consistent description of the halo nature of 31Ne with continuum and pairing correlations

Background: A relativistic structure model has previously been used to predict a halo structure for 31Ne (Zhang et al 2014 Phys. Lett. B 730 30), consistent with halo signatures from measured reaction cross sections of Ne isotopes bombarding Carbon targets. However, previous attempts to calculate those cross sections with reaction models were missing contributions from resonances and pairing correlations in their structure input. Purpose: Use a reaction model with our relativistic fully microscopic structure model input to predict these cross sections and momentum distributions and analyze for possible halo signatures. Methods: Structure input for exotic Ne isotopes were obtained via the analytical continuation of the coupling constant (ACCC) method based on the relativistic mean field (RMF) theory with Bardeen–Cooper–Schrieffer (BCS) pairing approximation, the RAB approach. Total reaction cross sections, one-neutron removal cross sections, and momentum distributions of breakup reaction products were calculated with a Glauber model using our relativistic structure input. Results: Our predictions of total reaction and one-neutron removal cross sections of 31Ne on a Carbon target were significantly enhanced compared with those of neighboring Neon isotopes, agreeing with measurements at 240 MeV/nucleon and consistent with a single neutron halo. Furthermore, our calculations of the inclusive longitudinal momentum distribution of the 30Ne and valence neutron residues from the 31Ne breakup reaction indicate a dilute density distribution in coordinate space, another halo signature. Conclusions: We give a full description of the halo nature of 31Ne that includes a self-consistent use of pairing and continuum contributions that makes predictions consistent with reaction cross section measurements. This approach can be utilized to determine the halo structure of other exotic nuclei.

Three-dimensional observation of GEMS grains: Their high-temperature condensation origin

GEMS (Glass with Embedded Metal and Sulfides) grains found in interplanetary dust particles are considered one of the most primitive materials in the Solar System, yet questions remain on how they formed. It has been suggested that GEMS grains are products of radiation processing and amorphization of sulfide and silicate mineral grains in the interstellar medium. Alternatively, GEMS grains are proposed to be disequilibrium condensation products in late-stage protosolar disks. We examined the 3D distributions of elements and inclusions within GEMS grains using TEM (transmission electron microscopic)-tomography to better constrain their possible formation processes. We found some core–shell particles composed of metals and amorphous silicates and observed a binary distribution of Mg/Si in amorphous silicates of GEMS grains. These properties are highly similar to the features of experimental condensation products. Furthermore, the location of sulfides only on the surface of GEMS and their larger sizes than metals are also consistent with the condensation experiments, where sulfides formed by sulfidation of metal grains with S-bearing gas species. Textures showing aggregation and possible coalescence of primary grains were also observed. Therefore, we conclude that GEMS grains are condensates from gas at high temperatures and some of them were aggregated.

Effect of Al2O3 in Refining Slag on the Cleanliness and Fatigue Property of Ultra-low-carbon Automotive Steel

The influence of Al2O3 content in refining slag on the cleanliness and fatigue property of ultra-low-carbon (ULC) automotive steel were investigated based on the industrial experiments. The inclusion-adsorption capacity of the refining slag was calculated and the total [O] (T.O) content of ULC automotive steel was measured. The number density, size distribution and morphology of inclusions were analyzed and their effects on the cleanliness and fatigue property of ultra-low-carbon (ULC) automotive steel were investigated. The results showed that as the Al2O3 content in refining slag increased from 19.92% to 39.73%, the inclusion-adsorption capacity of ULC automotive steel decreased from 210.30 down to 57.12, and the fatigue life from 1.4x104 down to 0.9x104 cycles, while the T.O content of steel increased from 12 up to18 ppm and the inclusion number density from 4 up to 9 per mm2.

Non-metallic inclusions in a superalloy during refining through cold crucible levitation melting process

Oxide and nitride inclusions in a Ni-based superalloy during the cold crucible levitation melting (CCLM) process were investigated towards a better understanding for the removal of inclusions from the metal. The number, morphology, size distribution and spatial distribution of inclusions were characterized using an automated scanning electron microscopy with energy-dispersive X-ray spectroscopy. Inclusions in the alloy were efficiently agglomerated and removed by floating during CCLM process. Inclusion clusters as big as 30-400 ?m were observed. Oxide clusters were efficiently floated during pouring process. The removal ratios of oxides were about 21% without pouring and 62% with pouring, respectively. Additionally, CCLM promotes the separation of oxides from nitrides. The effect of CCLM on the removal of nitride inclusions is not such evident compared with oxides. The mechanism of inclusion removal during CCLM was clarified.

Production of strange particles in jets and underlying events in pp collisions at √S = 13 TeV with ALICE

The production of strange KS0, Λ and multi-strange (Ξ± and Ω±) particles in jets and the underlying event in pp collisions at √S = 13 TeV has been studied with ALICE at the LHC. The pT-differential density of the particles produced in a jet is compared to the inclusive distribution. The corresponding (Λ + Λ¯)/2KS0 and (Ξ− + Ξ¯+)/(Λ + Λ¯) ratios in jets as a function of pT are also reported in this work. The pT-differential density distribution of hadrons associated with jets decreases slower than the one reported for inclusive particle production. The ratios measured in jets show a clear difference when compared to the inclusive ones at the intermediate pT range. The results provide an opportunity to test the strange and multi-strange particle production mechanisms with hard scattering.

The effect of different deoxidation processes on the inclusions characteristics in cold drawn tubing steel

ABSTRACT The non-metallic inclusions of cold-drawn tubing steel with different deoxidation processes were carried out in this study. The morphologies, compositions and size distribution of oxide inclusions in two heats were obtained by FE-SEM&EDS. The evolution of inclusion types in SM/AC process and SMA/C process were compared. In addition, it was summarized that the removed inclusion of SM/AC process was relatively more at LF station, while the removed inclusion of SMA/C process was mainly at VD station, which is closely related to the calcium treatment intensity at VD station. Moreover, kinetic model calculations of inclusion behaviour were carried out. Taking molten steel-slag-inclusion-refractory four-phase equilibrium into account, and considering the aggregation, floatation, remove and modification of inclusion. The results can well explain the existence of inclusions in the actual production process and can guide the removal of inclusions in different deoxidation processes and to know the removal limits.

Calculated-experimental model of distribution of non-metallic inclusions in the metal of welds by sizes

The Paton Welding Journal, 2021, №12. International Scientific-Technical and Production Journal «The Paton Welding Journal» «The Paton Welding Journal» has been published monthly since 2000 in English, ISSN 0957-798X. «The Paton Welding Journal» is a cover-to-cover English translation of the «Avtomaticheskaya Svarka» (Automatic Welding) journal. The «Avtomaticheskaya Svarka» journal has been published monthly since 1948 in Russian, ISSN 005-111X.

Technology penetration and human development nexus in middle-income countries: the synergy effect of inclusive resources distribution

ABSTRACT This paper intends to examine how interactions between equal distribution of resources and the information and communication technology (ICT) influence inclusive human development (inequality-adjusted human development) for 81 countries from middle-income countries within the period 2005–2017. We use a double-censored Tobit regression as it accounts for the dependent variable with a limited range. It exhibits the behavior that is consistent with the method of estimation. We employ the instrumental variable (IV) for the independent variables of interest to deal with simultaneity or reverse causality due to endogeneity. In light of established findings for this study, we conclude that equal distribution of public goods such as technologies could play a critical role in promoting inclusive human development. Supplementary policy repercussions are highlighted.

Influence of batch-to-batch material variations on grindability of a medium‑carbon steel

This study addresses the influence of material variations on the grindability of crankshaft steel. Most previous studies on the effect of material microstructure on grindability involve comparisons of significantly different steel grades. This study, in contrast, is focused on batch-to-batch grindability variations for one steel grade, a scenario frequently occurring in industry where batches from different steel makers are fed into a production line. For this purpose, a batch made of recycled steel and a batch made of ore-based steel were compared with regards to microstructure and grindability under identical grinding and dressing conditions. Although both batches met the same material specifications, microstructural variations were identified in terms of grain size and micro-constituents (inclusions, carbonitrides). While specific grinding energy, residual stress and full-width at half-maximum profiles of ground surfaces were the same for both batches, the recycled batch showed different and unfavorable variation in wheel wear and Barkhausen noise (BN) response. Larger fractions of oxide inclusions and larger grain sizes (affected by carbonitrides) were present in the recycled batch, which were the likely reasons for the differences in wheel wear and BN response, respectively. These findings may aid grindability improvement by steel-grade adjustments, e.g. modification of the distribution and type of inclusions and/or amount of elements forming carbonitrides. Furthermore, the results highlight the importance of understanding and controlling material microstructure, as existing in-line quality by BN control may not always be able to correctly indicate surface integrity, which could lead to misinterpretations (e.g. false part-rejection on the assumption of grinding burn).

Distribution of Bi-MnS inclusions in newly solidified steels subjected to horizontal cooling

ABSTRACT To further study the distribution and concentration of Bi particles in various cooling zones in newly solidified Bi content 1215 MS steels and to explore the relationship between cooling rate (R) and dendrite arm spacing, the horizontal solidification experiments were carried out by altering the R. Thermodynamics show liquid Bi was immiscible in Fe, which precipitated in the grain boundary and tended to co-exist with sulfides. Under moving rate ν = 0.2 mm/s, the average sizes of Bi particles and Bi-MnS inclusions in the chilled boundary, columnar grain and quenching grain zones were 1.2 μm, 1.4 μm, and 1.5 μm, while under v = 0.4 mm/s, those were 1.3 μm, 1.6 μm, and 1.2 μm, respectively. The average dendrite arm spacing of the solidified steel decreased with increasing moving rate (v). At R = 0.367 and 0.690°C/s, the average equivalent diameter () of the inclusions in the columnar grain zone was respectively 1.102 μm and 1.119 μm. Under v = 0.4 mm/s, the concentrations of Bi particles in 1200 ppm and 2800 ppm Bi solidified steels in the chilled boundary, solidification front and center of the quenching grain zone were 0.0267%, 0.0375%, 0.0443%, 0.0463%, 0.0659%, and 0.0832%, respectively.

Reconfigurable magneto-mechanical metamaterials guided by magnetic fields

In this work, we show through the use of experiments validated by computer simulations the potential of a novel accordion-like magneto-mechanical metamaterial to change its linear dimensions in a controllable manner upon being subjected to a uniform external magnetic field, a system which essentially acts as an actuator guided by a magnetic field. We also show that irrespective of the magnitude of the external magnetic field, this system can return to its initial shape due to the appropriate distribution of magnetic inclusions within the system. Finally, it is also shown that the proposed accordion-like system can be considered as a building block for a larger three-dimensional system where its properties may undergo a transition from positive to negative Poisson’s ratio, depending solely on the magnitude and the orientation of the external magnetic field. This concept is very interesting from the point of view of numerous applications such as protective materials or vibration dampers where the mechanical properties of the material could be fine-tuned to increase its efficiency without the need of reconstructing the system.

Numerical Simulation on Motion Behavior of Inclusions in the Lab-Scale Electroslag Remelting Process with a Vibrating Electrode

In order to meet the requirement of high-quality ingots, the vibrating electrode technique in the electroslag remelting (ESR) process has been proposed. Non-metallic inclusions in ingots may cause serious defects and deteriorate mechanical properties of final products. Moreover, the dimension, number and distribution of non-metallic inclusions should be strictly controlled during the ESR process in order to produce high-quality ingots. A transient 2-D coupled model is established to analyze the motion behavior of inclusions in the lab-scale ESR process with a vibrating electrode, especially under the influence of the vibration frequency, current, slag layer thickness, and filling ratio, as well as type and diameter of inclusions. Simulation model of inclusions motion behavior is established based on the Euler-Lagrange approach. The continuous phase including metal and slag, is calculated based on the volume of fluid (VOF) method, and the trajectory of inclusions is tracked with the discrete phase model (DPM). The vibrating electrode is simulated by the user-defined function and dynamic mesh. The results show that when the electrode vibration frequency is 0.25 Hz or 1 Hz, the inclusions will gather on one side of the slag layer. When it increases from 0.25 Hz to 1 Hz, the removal ratio of 10 μm and 50 μm inclusions increases by 5% and 4.1%, respectively. When the current increases from 1200 A to 1800 A, the flow following property of inclusions in the slag layer becomes worse. The removal ratio of inclusions reaches the maximum value of 92% with the current of 1500 A. The thickness of slag layer mainly affects the position of inclusions entering the liquid-metal pool. As the slag layer thickens, the inclusions removal ratio increases gradually from 82.73% to 85.91%. As the filling ratio increases, the flow following property of inclusions in the slag layer is enhanced. The removal ratio of 10 μm inclusions increases from 94.82% to 97%. However, for inclusions with a diameter of 50 μm, the maximum removal ratio is 96.04% with a filling ratio of 0.46. The distribution of 50 μm inclusions is significantly different, while the distribution of 10 μm inclusions is almost similar. Because of the influence of a vibrating electrode, 10 μm Al2O3 and MnO have a similar removal ratios of 81.33% and 82.81%, respectively.

Transmission Loss Analyses on Different Angular Distributions of Periodic Inclusions in a Porous Layer

Transmission Loss Analyses on Different Angular Distributions of Periodic Inclusions in a Porous Layer

Optimisation of rGO-enriched nanoceramics by combinatorial analysis

The design of new ceramic materials with specific thermo-electrical and mechanical properties is important for a range of engineering applications. Recent research has demonstrated that inclusion of soft reduced graphene oxide (rGO) in hard ceramic matrix produces nano-structured ceramic composites with improved electrical conductivity and fracture toughness. The emergent properties of such composites are strongly related to the mass fraction and spatial distribution of rGO inclusions. Their micro-structure includes sub-structures with different dimensions - 1D, 2D and 3D - which calls for entirely new approaches to characterisation and design. In this theoretical work, a new discrete (combinatorial) strategy is proposed that allows for capturing all sub-structures, employing elements of algebraic topology and modern graph theory. It is demonstrated how this strategy can be applied to the flexible design of nano-structured ceramics with a superior balance between conductivity and resistance to fracture.

The relationship between inclusions characteristic parameters and bending fatigue performance of 20Cr2Ni4A gear steel

Common heavy-duty 20Cr2Ni4A gear steel is widely used in industrial systems, but there are still problems with its use, such as materials processing issues and a short fatigue life during use. These drawbacks prevent 20Cr2Ni4A from meeting the quality requirements for heavy-duty gear steel in modern industrial systems. Therefore, in practical engineering application, the fatigue life of steel will be predicted to ensure that the fatigue failure of gear steel will not occur in the normal service process. By analysis of the bending fatigue process of structural steel, researchers found that almost every failure is closely related to the size, location and mechanical state of inclusions in the steel. Therefore, in order to accurately characterize the impact of inclusions on fatigue performance, we first used ASPEX inclusion field detection instrument and nanoindentation analyser to make statistics of all inclusions in the two steels, and the contents, distribution, average size and mechanical properties of inclusions in 20Cr2Ni4A steel were accurately counted. Subsequently, the bending fatigue life of two differently processed steels was tested, and a P-S-N curve was drawn. Then, the fatigue fracture was analysed and four fatigue fracture models were summarized to determine the influence of inclusions in the fatigue process. Based on the models by Nisha S, the effects of the number, area, and types of the inclusions were added as corrections, and a new set of life prediction models was proposed. The model was verified by experiments, and the results have a high accuracy. Thus, this approach can be applied to the prediction of the fatigue life of 20Cr2Ni4A steel.

Investigation into the geometry and distribution of oil inclusions in sea ice using non-destructive X-ray microtomography and its implications for remote sensing and mitigation potential

As climate change brings reduced sea ice cover and longer ice-free summers to the Arctic, northern Canada is experiencing an increase in shipping and industrial activity in this sensitive region. Disappearing sea ice, therefore, makes the Arctic region susceptible to accidental releases of different types of oil and fuel pollution resulting in a pressing need for the development of appropriate scientific knowledge necessary to inform regulatory policy formulation.In this study, we examine the microstructure of the surficial layers of sea ice exposed to oil using X-ray microtomography. Through analysis, 3D imaging of the spatial distribution of the ice's components (brine, air, and oil) were made. Additional quantitative information regarding the size, proximity, orientation, and geometry of oil inclusions were computed to ascertain discernable relationships between oil and the other components of the ice. Our results indicate implications for airborne remote sensing and bioremediation of the upper sea ice layers.