Arrangement Of Aggregates Research Articles

Evaluation of Degradation Mechanisms of Polymer Electrolyte Fuel Cell Using DEM Simulation

Polymer electrolyte fuel cells (PEFCs), which have various advantages such as high power output, high conversion efficiency, and low operating temperature, are expected to be applied to heavy-duty vehicles with a high environmental impact, and further performance and durability improvements are required for practical use. Currently, the degradation of power generation performance due to long-term operation is an issue in the practical application of PEFCs and it is considered that one of the causes of this degradation is the corrosion of the carbon support. However, the dynamic process of catalyst layer structure change due to CB particle corrosion has not yet been clarified, and the relationship between power generation performance change and catalyst layer microstructure has not been linked. It is also considered difficult to do so experimentally with the current state of the art. In this study, we focused on analyzing the dynamic structural change behavior of the catalyst layer due to corrosion of the carbon support by using numerical model simulation. By using the catalyst layer created by the numerical model, we simulated the power generation reaction and to identify the factors that cause the degradation of power generation performance.Discrete element method (DEM) was used to calculate the structure of catalyst layer by using carbon support, which is a branch-like aggregate of carbon black (CB) particles. The aggregate arrangement was determined based on the translational and rotational equations of motion for individual aggregates, elasticity between particles, and viscous damping1). Based on previous studies2) 3), the carbon corrosion reaction caused by the reaction between the products of the carbon surface reaction and the platinum oxidation reaction is considered, reflecting localized carbon corrosion within the catalyst layer. Also, we hypothesized that the porosity increases due to the shrinkage of CB particles in the early stage of corrosion, followed by a decrease in porosity and thickness due to the separation of the sintered parts of the CB particles that compose the aggregates. Furthermore, in this model, the fastening pressure is related to the timing of the structural collapse of the catalyst layer. Therefore, in this study, we performed calculations considering the neck breakdown of the aggregate due to the fastening pressure. The particles were assumed to be non-porous carbon (Vulcan), and calculations were performed under the same initial conditions as actual carbon black: primary particle size of 30 nm and aggregate diameter of 400 nm. Ionomers were assumed to be uniformly coated and not change in volume during degradations. The power generation reactions considering transport and diffusion were simulated for the catalyst layer structures fabricated by DEM, and the factors that cause differences in power generation performance were evaluated for each catalyst layer structure. In this study, performance degradation due to aggregation and desorption of platinum was neglected because we focused only on the effects of structural changes.Dynamic degradation of the catalyst layer was calculated considering localized corrosion due to carbon oxidation and structural collapse due to fastening pressure.The results showed a significant change in the catalyst layer structure despite the small amount of carbon corrosion. It was also suggested that the fastening pressure affects the amount of carbon corrosion when structural collapse occurs.AcknowledgmentThis study was supported by New Energy and Industrial Technology Development Organization (NEDO).

Influence of randomly placed resonant aggregates on the attenuation properties of metaconcrete: A numerical study

Concrete is a key material for many structural components in engineering, but its acoustic performance remains under discussion. Hence, the potential of the so-called metaconcrete has gained attention in research, mainly due to its capability to control vibrations and sound transmission when resonant aggregates are embedded in the concrete. These resonant aggregates are designed to have resonant frequencies regarding frequency bands of interest, so the interaction with the incident sound waves is attenuated within those frequencies. While available research has focused on the characterization of metaconcrete with a periodic arrangement of resonant aggregates, there is a gap regarding how their random allocation affects the characterization of metaconcrete. This study focuses on the numerical analysis of metaconcrete and the influence of randomly placed resonant aggregates on its attenuation properties. The numerical approach concentrates on the aggregate's material composition, location and volume fraction within the concrete to identify configurations that exhibit great wave attenuation. The results have shown that the attenuation effect is substantially advantageous when using a multi-frequency configuration for aggregates within the metaconcrete. Additionally, the random embedding of resonant aggregates offers a practical solution for their application in concrete structures.

Micro-Structure Analysis and Mechanical Behaviour of Hot Mix Asphalt Modified with Reclaimed Asphalt Pavement Using Palm Kernel Shell Ash as Mineral Filler

In pavement construction and production of hot mix asphalt HMA, the use of industrial and agricultural waste has gained much relevance because of its economic and environmental benefits. This research examined the effects of palm kernel shell ash PKSA on the physical and volumetric properties of HMA modified with reclaimed asphalt pavement RAP. All preliminary test conducted on the modified asphalt mixture in accordance with relevant standards showed adequacy for use in production of HMA. Marshall method of mix design was adopted for the HMA production. The bitumen content was varied from 4.5 to 6.5% (at intervals of 0.5%). The palm kernel shell ash was varied from 25% to 75% (at interval of 25%). A maximum stability of 7.1kN was recorded at 5.5% bitumen content which is a little increment in strength but good significance in material (virgin bitumen) when compared to the maximum stability of 6.9kN at 6% bitumen obtained from the control mix. The microstructural analysis of the hot mix asphalt done on the palm kernel shell ash PKSA showed a rough surface texture needed in flexible pavement construction and when comparison was done between the control specimen and the modified specimen, it shows an improvement in the interlocking arrangement of aggregates resulting in a denser mixture for the modified hot mix asphalt. In conclusion this study confirms that a blend of a 50% RAP and 50% virgin aggregates with 50% palm kernel shell ash PKSA as mineral filler at 5% bitumen content can improved strength performance of HMA, hence, the effect of PKSA as a mineral filler in HMA containing RAP is significant.

Unraveling the nanostructures and self-assembly behavior of perfluorosulfonic acid in water/ethanol solvent: Effect of EW and side-chain chemistry

The perfluorosulfonic acid (PFSA) ionomers are key materials for proton exchange membranes (PEMs) and catalyst layers (CLs). Their morphology is profoundly influenced by the chain assembly behavior of PFSA in dispersions. Hence, we combine the characterization techniques of dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), and cryo-transmission electron microscopy (Cryo-TEM) to study the nanostructures of PFSA dispersions, and provide a structure model for diverse PFSA ionomers in water/ethanol solvent. It is seen that PFSA ionomers self-assembly into a rod-like particle in dilute dispersion. As the concentration increases, the primary rod aggregates gradually assemble into a swollen- or Gaussian-network structure. Beyond this feature, we see that different PFSA ionomers show different nanostructures in dispersion. For the long-side-chain (LSC) PFSA ionomers, the 800-LSC PFSA tends to form monodisperse rod-like aggregates that is in a highly ordered arrangement with a rod diameter of 3.16 nm and a length of 28.72 nm. As the equivalent weight (EW) increases to 960, the poor solubility of the main chains in water/ethanol solvents leads to the “end-to-end” assemblies of the primary rod particles and dendritic secondary aggregates. The short-side-chain (SSC) PFSA ionomer that shares the same backbone with 960-LSC PFSA exhibit remarkable mono-dispersity and ordered arrangement of rod-like aggregates in water/ethanol solvents due to the strong electrostatic repulsion.

Effect of recycled coarse aggregate model arrangement mode on the axial compressive performance of MRCAC

The paper presents the results of studies on based the universal morphology of recycled coarse aggregates in reality, an idealized model of recycled coarse aggregates was prepared using stones. Axial compressive strength tests were conducted on prism-shaped specimens of Modeled Recycled Coarse Aggregate Concrete (MRCAC), which were prepared with different old cement mortar coverages and aggregate arrangements. Through comparison with experimental data, the reliability of the finite element analysis model was determined. It was found that the arrangement of MRCA had a significant impact on the failure characteristics and elastic modulus of MRCAC. Thus, different arrangement modes affected the stress distribution within the specimens, resulting in significantly different axial compressive strength.

Magnetic elastomers as specific soft actuators – predicting particular modes of deformation from selected configurations of magnetizable inclusions

Amongst the various fascinating types of material behavior featured by magnetic gels and elastomers are magnetostrictive effects. That is, deformations in shape or changes in volume are induced from outside by external magnetic fields. Application of the materials as soft actuators is therefore conceivable. Mostly, straight contraction or extension of the materials along a certain direction is discussed and investigated in this context. Here, we demonstrate that various further, different, higher modes of deformation can be excited. To this end, different spatial arrangements of the magnetizable particles enclosed by the soft elastic matrix, which constitute the materials, need to be controlled and realized. We address various different types of spatial configurations of the particles and evaluate resulting types of deformation using theoretical tools developed for this purpose. Examples are sheet-like arrangements of particles, circular or star-shaped arrangements of chain-like aggregates, or actual three-dimensional star-like particle configurations. We hope to stimulate with our work the development of experimental design and engineering methods so that selected spatial particle arrangements in magnetic gels and elastomers can be put to reality. Overall, we in this way wish to promote the transfer of these promising class of materials to real-world applications.

Label-free visualization of unfolding and crosslinking mediated protein aggregation in nonenzymatically glycated proteins.

Nonenzymatic glycation (NEG) unfolds and crosslinks proteins, resulting in aggregation. Label-free evaluation of such structural changes, without disturbing molecular integrity, would be beneficial for understanding the fundamental mechanisms of protein aggregation. The current study demonstrates the assessment of NEG-induced protein aggregation by combining autofluorescence (AF) spectroscopy and imaging. The methylglyoxal (MG) induced protein unfolding and the formation of cross-linking advanced glycation end-products (AGEs) leading to aggregation were evaluated using deep-UV-induced-autofluorescence (dUV-AF) spectroscopy in proteins with distinct structural characteristics. Since the AGEs formed on proteins are fluorescent, the study demonstrated the possibility of autofluorescence imaging of NEG-induced protein aggregates. Autofluorescence spectroscopy can potentially reveal molecular alterations such as protein unfolding and cross-linking. In contrast, AGE-based autofluorescence imaging offers a means to visually explore the structural arrangement of aggregates, regardless of whether they are amyloid or non-amyloid in nature.

Microstructure study of natural marine clay in loading and unloading processes

The microstructure evolutions of natural marine clay during loading and unloading processes were investigated using undrained triaxial tests. The pore distribution and arrangement of soil particles and aggregates were measured by mercury intrusion porosimetry (MIP) and field emission scanning electron microscope (FESEM) tests, respectively. The results show that pores do not always collapse into smaller ones with stress levels increasing; the destruction of cemented soil structure will lead to the connection of small pores into large pores. In the consolidation process, as the consolidation pressure increased from 0 to 100 kPa, the total specific surface decreased from 20.01 mm2/g to 17.42 mm2/g. Conversely, the total specific surface increased from 17.42 mm2/g to 19.25 mm2/g as the confining pressure surpassed the preconsolidation pressure, indicating the formation of new surfaces. The rebound effect during the unloading process is another factor causing the increase in pore volume, but the destruction of the soil structure can significantly reduce this effect. The microscopic morphology at the point of soil failure under high stress levels in both loading and unloading processes tended to be similar, as the soil structure was completely destroyed.

Highly luminescent soft aggregates and films assembled by amphiphilic polyoxometalate complex in a polymerizable aprotic ionic liquid

Hybrid co-assembly from lanthanide-containing polyoxometalates (POMs) and surfactants could efficiently optimize the formed aggregate luminescent properties and structural diversity. Meanwhile, compared to conventional solvents, aprotic ionic liquids (ILs) are not only excellent assembly media but also ideal solvents for luminescent lanthanide compounds. Therefore, in this work, the luminescent amphiphilic POM complex, namely surfactant-encapsulated POM hybrid (SEP) was initially prepared mainly through electrostatic interaction from polyanionic lanthanide-containing POM, Na9(EuW10O36)·32H2O (EuW10) and cationic surfactant, 1-octadecyl-3-methylimidazolium bromide ([C18mim]Br, OB). Then, highly luminescent lamellar micro-fiber aggregates were assembled by SEP in a polymerizable imidazolium-IL solvent, i.e. 1-vinyl-3-butyl imidazolium terafluoroborate ([Vbim]BF4). After morphology and structure characterizations for soft aggregates in detail, a lamellar aggregation arrangement mechanism was proposed. Further through in situ photopolymerization for such aggregate matrices, the flexible and organized films with enhanced luminescent properties were obtained. Our work indicates that the rational design of polymerizable organized aggregate matrices in ILs could greatly improve the photophysical properties of such luminescent soft materials and also expand their practical applications.

Strategy for the Mix Design of Building Earthen Materials Made of Quarry By-Products

The use of quarry by-products can enable the commercialization of a clay building material (reconstituted earth) thanks to minimal valorized and perennial stocks of materials. This study shows that quarry by-products can be used to mix design a clay-based building material for the manufacture of CEB. These soils are composed of quarry tailing and clayey muds. Proctor and dry compressive strength tests have shown that the proportion of mud that achieves the highest possible compressive strength is a balance between increasing density through the aggregate arrangement, increasing clay activity, and decreasing density through the increase in water content. These tests resulted in the formulation of materials with compressive strengths of 5.8 MPa and 8.4 MPa at densities of 2135 kg/m3 and 2178 kg/m3. The influence of mud incorporation on the material granulometry and on its characteristics was also studied. Moreover, a model allowing us to link the compressive strength, the clay activity, and the dry density is proposed for the materials composed of quarry by-products. This model enables us to facilitate the mix design and the standardization of the earth material.

Light-Scattering Properties for Aggregates of Atmospheric Ice Crystals within the Physical Optics Approximation

This paper presents the light-scattering matrices of atmospheric-aggregated hexagonal ice particles that appear in cirrus clouds. The aggregates consist of the same particles with different spatial orientations and numbers of these particles. Two types of particle shapes were studied: (1) hexagonal columns; (2) hexagonal plates. For both shapes, we studied compact and non-compact cases of particle arrangement in aggregates. As a result, four sets of aggregates were made: (1) compact columns; (2) non-compact columns; (3) compact plates; and (4) non-compact plates. Each set consists of eight aggregates with a different number of particles from two to nine. For practical reasons, the bullet-rosette and the aggregate of hexagonal columns with different sizes were also calculated. The light scattering matrices were calculated for the case of arbitrary spatial orientation within the geometrical optics approximation for sets of compact and non-compact aggregates and within the physical optics approximation for two additional aggregates. It was found that the light-scattering matrix elements for aggregates depend on the arrangement of particles they consist of.

Virtual modeling of asphalt mixture beam using density and distributional controls of aggregate contact

AbstractThe characteristic indicators of aggregate contacts in asphalt mixtures, including the number, orientation, and area of contact regions, significantly affect skeleton morphology and mixture stability. To investigate the influence of indicators on mixture stability, structures with diverse characteristics of aggregate contacts are required. This study proposes an algorithm for the virtual modeling of asphalt mixture beams, which supports the density and distributional controls of aggregate contacts in the microstructure. The methodology comprises three main steps: (1) three‐dimensional models of coarse aggregates conforming to the predefined gradation and volumetric content are randomly selected from a digital library of realistic aggregates, (2) contact relations of aggregates are established during the adaptive arrangement of aggregates in samples with prescribed control parameters of aggregate contact using self‐developed codes, and (3) air voids are randomly scattered in the sample without overlapping aggregates according to the volumetric content of the air voids, and an asphalt mortar model is then constructed using Boolean operations. Four beam samples with different contact characteristics were obtained using the proposed method to conduct simulations of three‐point bending tests. The number and spatial distribution of aggregate contacts in beam models are consistent with the prescribed parameters, showing the reliability of the proposed method for the control of aggregate contact in asphalt mixtures. A comprehensive comparison of the results of the laboratory test and simulations validates the ability of the digital beam to capture the macroscale response of asphalt mixtures. Furthermore, simulation results indicate that the sample with the greatest number and distribution uniformity of aggregate contacts has the largest peak strength and fracture energy, which is beneficial for the understanding of the relationship between the indicators of aggregate contacts and the rutting and fatigue resistance of mixtures.

Elastoviscoplasticity, hyperaging, and time-age-time-temperature superposition in aqueous dispersions of bentonite clay.

Clay slurries are both ubiquitous and essential in the oil exploration industry, and are most commonly employed as drilling fluids. Due to its natural abundance, bentonite clay is often the de facto choice for these materials. Understanding and predicting the mechanical response of these fluids is critical for safe and efficient drilling operations. However, rheological modeling of bentonite clay suspensions is complicated by the fact that thermally-driven microscopic arrangements of particle aggregates lead to a continual evolution of the viscoelastic properties and the yield stress of the suspension with time. Ergodic relations fundamental to linear viscoelastic theory, such as the Boltzmann superposition principle, do not hold in this scenario of 'rheological aging'. We present an approach for modeling the linear viscoelastic response of aging bentonite suspensions across a range of temperatures that is based on the transformation from laboratory time to an effective 'material time' domain in which time-translation invariance holds, and the typical relations of non-aging linear viscoelastic theory apply. In particular, we model the constitutive relationship between stress and strain-rate in the bentonite suspensions as fractional Maxwell gels with constant relaxation dynamics in the material time domain, in parallel with a non-aging Newtonian viscous contribution to the total stress. This approach is supported by experimental measurements of the stress relaxation and rapid time-resolved measurements of the linear viscoelastic properties performed using optimized exponential chirps. This data is then reduced to master curves in the material domain using time-age-time superposition to obtain best fits of the model parameters over a range of operating temperatures.

Assessing the effect of different compaction mechanisms on the internal structure of roller compacted concrete

Compaction plays a pivotal role in the formation of the aggregate skeleton of concrete mixtures, especially for stiff mixes such as Roller Compacted Concrete (RCC). RCC is compacted in the field with combinations of different energies (kneading/shear, impact, static & vibratory pressure), whereas various compactors are used, viz. modified Proctor (MP), vibratory hammer (VH), vibratory table (VT), and gyratory compactor (GY) in the laboratory to mimic the field compaction. Since the compaction mechanism is different in these compactors compared to field rollers, the behaviour of RCC is also distinct and warrants a fundamental study. In this study, the dominating parameters affecting the mesostructural arrangement of aggregates within the concrete skeleton when compacted with different mechanisms are comprehensively studied and compared with the field compacted specimens using several image processing techniques. The mesostructural parameters considered are interparticle spacing & distribution, aggregates segregation, orientation, morphology & breakage post-compaction, and crack length. The results indicate a higher possibility of getting better aggregate distribution and strength while a lower segregation potential when compacted with VH, followed by MP. However, the use of MP could alter the aggregates’ morphological characteristics due to the breakage of particles during the compaction process. On the other hand, VT and GY could exhibit similar interparticle distances to the field specimens but could not demonstrate similar performance in terms of strength and durability. The dominating parameters affecting aggregates’ spatial distribution are found to be aggregate-to-mortar ratio, interparticle distance, and the mechanism associated with each compaction technique.

The Influence of Mortar's Poisson Ratio and Viscous Properties on Effective Stiffness and Anisotropy of Asphalt Mixture.

This paper presents the results of a research study and analysis conducted to determine the degree of anisotropy of asphalt concrete in terms of its initial elastic properties. The analysis of asphalt concrete was focused on determining the effective constrained stiffness modulus in three mutually perpendicular directions based on the finite element method. The internal structure of the asphalt concrete was divided into the mortar phase and the mineral aggregate phase. Static creep tests using the Bending Beam Rheometer were conducted for the mortar phase to fit the rheological model. The aggregate arrangement and orientation were analysed using an image analytical technique for the mineral phase. The Finite Element Method (FEM) meshes were prepared based on grey images with an assumption of plane strain in 2D formulation. Using the FEM model, the tension/compression tests using selected characteristic directions were conducted, and the effective constrained stiffness moduli were estimated. This study showed a dominant horizontal direction for all coarse aggregates resulting from the normal force of the road roller and paving machines during laying and compaction on a road site. Depending on the values of the mortar's mechanical parameters and the load direction, the effective stiffness modulus might differ by ±20%. Based on the FEM analysis, this result was proven and commented on through an effective directional modulus evaluation and a presentation of internal stress distribution. Depending on the shape and orientation of the aggregates, it was possible to observe local "stress bridging" (transferring stresses from aggregate to aggregate when contacting). Moreover, the rheological properties of the mortar were considered by assuming two limiting situations (instantaneous and relaxed moduli), determining the bands of all possible solutions. In the performed FEM analysis, the influence of the Poisson ratio was also considered. The analysed asphalt concrete tends to be isotropic when the Poisson's mortar ratio is close to the value of 0.5, which agrees with the physical expectations. The obtained results are limited to particular asphalt concrete and should not be extrapolated to other asphalt mixture types without prior analysis.

Experimental and computational modeling of chloride transport behavior in fully recycled coarse aggregate concrete

Exploitation of recycled coarse aggregate (RCA) aimed to produce fully recycled coarse aggregate concrete (FRCAC) has attracted more attention due to the growing requirements for sustainable development and carbon neutralization. In this paper, a novel computational model is developed to study the chloride migration behavior in FRCAC at the mesoscopic level. RCAs are generated by a random convex polygon algorithm to approximate the realistic arrangement, shape and polyphase components of aggregates. FRCAC with different RCA volume fractions (0 %, 20 %, 35 % and 50 %) was made by the optimized triple mixing method (OTM), and its chloride transport behavior was investigated by drying-wetting cycles test exposed to sodium chloride solution (50 g/l) for 250 days. The experimental results demonstrate that the transport depth and concentration of chloride increase with the augment of the RCA volume fraction. The availability and universality of the present computational model were validated by comparing with the experimental data. The numerical results show that RCA has both adsorption and barrier effects on the chloride transport, which makes the chloride isoline bend and the flow direction change. Finally, it is demonstrated that chloride diffusivity in 2D case increases compared with 1D case. The findings of presented study can better enhance the understanding of the chloride transport mechanism in FRCAC at mesoscopic.

A near-infrared absorbing ring-fused quinoid-bisboron pyrrole dye with double BF2 chelation

Ring-fused quinoid-bisboron pyrrole dyes with double BF2 chelation (QBBP) were prepared for the first time. According to X-ray crystallographic analysis, the centrosymmetric structure of QBBP was confirmed. The core of the central quinone moiety and two ring-fused pyrroles is almost planar, and the arrangement of aggregates involve J-type packing. Bisboron dye QBBP underwent two successive one-electron reduction and two successive one-electron oxidation processes. QBBP absorbs in the near-infrared (NIR) with a high molar extinction coefficient. Although QBBP shows no fluorescence and low intersystem crossing (ISC) efficiency, it has considerable photothermal conversion efficiency and is desirable for a photothermal-photodynamic therapy agent.

Macromolecular conjugated cyanine fluorophore nanoparticles for tumor-responsive photo nanotheranostics

For photothermal therapy (PTT), the improved targeting can decrease the dosage and promote the therapeutic function of photothermal agents, which would effectively improve the antitumor effect. The tumor microenvironment (TME) and cells are targets in designing intelligent and responsive theranostics. However, most of these schemes have been limited to the traditional visible and first near-infrared (NIR-I) regions, eager to expand to the second near-infrared (NIR-II) window. We designed and synthesized a polyethylene glycol conjugated and disulfide-modified macromolecule fluorophore (MPSS). MPSS could self-assemble into core–shell micelles in an aqueous solution (MPSS-NPS), while the small molecule probes were in a high aggregation arrangement inside the nanoparticle. The pronounced aggregation quenching (ACQ) effect caused them to the “sleeping” state. After entering the tumor cells, the disulfide bonds in MPSS-NPS broke in response to a high concentration of glutathione (GSH) in TME, and the molecule probes were released. The highly aggregated state was effectively alleviated, resulting in distinct absorption enhancement in the near-infrared region. Therefore, the fluorescence signal was recovered, and the photothermal performance was triggered. In vitro and in vivo studies reveal that the Nano-system is efficient for the smart NIR-II fluorescence imaging-guided PTT, even at a low dosage and density of irradiation.

Explicit spatial modeling at the pore scale unravels the interplay of soil organic carbon storage and structure dynamics.

The structure of soil aggregates plays an important role for the turnover of particulate organic matter (POM) and vice versa. Analytical approaches usually do not disentangle the continuous re-organization of soil aggregates, caught between disintegration and assemblage. This led to a lack of understanding of the mechanistic relationship between aggregation and organic matter dynamics in soils. In this study, we took advantage of a process-based mechanistic model that describes the interaction between the dynamic (re-)arrangement of soil aggregates, based on dynamic image analysis data of wet-sieved aggregates, to analyze the turnover of POM, and simultaneous soil surface interactions in a spatially and temporally explicit way. Our novel modeling approach enabled us to unravel the temporal development of aggregate sizes, organic carbon (OC) turnover of POM, and surface coverage as affected by soil texture, POM input, and POM decomposition rate comparing a low and high clay soil (18% and 33% clay content). Our results reveal the importance of the dynamic re-arrangement of soil structure on POM-related turnover of OC in soils. Firstly, aggregation was largely determined by the POM input fostering aggregates through additional gluing joints outweighing soil texture at lower decomposition rate, whereas at higher decomposition rate, soil texture had a higher influence leading to larger aggregates in the high clay soil. Secondly, the POM storage increased with clay content, showing that surface interactions may delay the turnover of OC into CO2 . Thirdly, we observed a structural priming effect in which the increased input of POM induced increased structural re-arrangement stimulating the mineralization of old POM. This work highlights that the dynamic re-arrangement of soil aggregates has important implications for OC turnover and is driven by underlying surface interactions where temporary gluing spots stabilize larger aggregates.

Aggregation arrangement features of network interface channels in multiprocessor computing systems

The paper identifies ways to increase the multiprocessor computing system performance by reorganizing the architecture of its network interface. It is shown that the computational parallelization performance significantly depends on many factors, the most essential of which is the data transfer between the boundary nodes of a multiprocessor system, which is the algorithm's slowest part and can significantly reduce the effect of increasing the number of processors. Hence, it was established that improving the multiprocessor systems performance by reorganizing the network interface structure is relevant interesting nowadays, and its study is at the active development stage. The research aims at the aggregation arrangement of network interface channels in multiprocessor computing systems. It is shown that the main channel aggregation mode advantage is that the data interchange speed is significantly increased, as well as the reliability of the cluster system.