Additional Sublayer Research Articles

Reliability-oriented segmentation of sublayers in geologically uncertain substrate: A case study of the Żelazny Most TSF

In this study, a new approach is proposed for the stability analysis of tailings storage facility (TSF) dams. Given the considerable scale of such objects, te correct identification of geotechnical layers for computational models and the determination of reliable parameters can present significant challenges. Therefore, the investigation focuses on distinguishing additional sublayers within a geological substratum to enhance the credibility of stability assessment. The procedure of sublayer separation is directly based on soil parameters derived from geotechnical tests and it aims at reducing the variability in the parameters of individual sublayers. Specifically, the segmentation technique known as the Gaussian mixture model (GMM) is employed for this purpose. Subsequently, the spatial arrangement of sublayers within the finite element model domain is identified using the kriging technique. Utilizing Monte Carlo simulations statistical distribution of factor of safety (FOS) is obtained for the structure. Finally, the stability is assessed using the Cornell reliability index. The application of this developed methodology is demonstrated through a case study of the Żelazny Most TSF. Additional sublayers are identified in Neogene clays constituting the dominant layer beneath the facility. In total, six different segmentation variants are proposed and their performance is evaluated. The results show that the segmentation of additional sublayers produces a clear reduction in the scatter of the FOS. Consequently, the estimated simplified reliability index surpasses that of the case, which does not involve the separation of additional layers.

Tribological properties of Al2O3 layers after thermo-chemical treatment

The article presents the influence of the thermo-chemical treatment of Al2O3 layers on their tribological properties. The Al2O3 layers were produced on the EN AW-5251 aluminium alloy by means of direct current anodizing in a three-component electrolyte. For the sake of comparison, some of the samples were thermochemically treated in three liquids (sodium sulphate solution, sodium dichromate solution, distilled water). The parameters of the production and thermo-chemical treatment were selected on the basis of two Hartley's plans. The tribological properties were determined on the basis of a tribological test carried out for a pin-on-disc friction pair on a T-17 tester in reciprocating motion. The tests were carried out in conditions of technically dry friction. Thanks to the tests, coefficient of friction µ and the mass wear, together with the intensity of the material wear were determined. The use of thermo-chemical treatment in the sodium dichromate solution contributed to an increase in coefficient of friction μ and a reduction in the wear intensity of the polymer from 36 μg/km (layer without thermo-chemical treatment) to 21.33 μg/km (layer after thermo-chemical treatment in the sodium dichromate solution).The conducted stereometric tests before and after the tribological test for selected samples allow the authors to state that the thermo-chemical treatment in the sodium dichromate solution increases the amplitude parameters of surface roughness. The study of the surface morphology of the layer with the lowest mass wear showed the formation of an additional sub-layer as a result of thermo-chemical treatment carried out in the sodium dichromate solution.

Identifying board of director network influence for firm characteristics

We utilize multiplex network analysis to evaluate the relationship between firms’ characteristics and board of director networks. Studying a sample of 384 board members of 20 largest US energy and utility firms, 10 from each sector, the firms are differentiated by a clustering analysis on their firm-level characteristics. The firms’ board member connections are represented in a multiplex network consisting of two layers, one for the board members’ direct connections and another for their indirect connections. Four additional sub-layers are identified for each major layer of the multiplex network to represent corporate, non-profit organization, education and government/military connections between the board members. Weights assigned to each layer of the multiplex network allow combining their effect in the resulting single layered directors’ network. The weights of the multiplex directors’ network are learned by optimally relating firms’ director network characteristics with firm clusters’ characteristics. We observe that director network displays significant connectivity at all multiplex network layers and firms belonging to the same cluster display similar director network characteristics, specifically enhanced by appropriate weighting of director network layers. The optimal value of network sub-layer weights indicate that, while corporate board member connections play the most significant role, the non-profit and military & government connections are also important, where non-profit connections lead to inferior firm outcomes.

Highly Accurate and Numerically Stable Matrix Computations of the Internal Impedance of Multilayer Cylindrical Conductors

The inhomogeneous wires are composed of different metals to exploit the advantages of particular material. One of the most relevant electrical parameter used to describe the conductor is its internal impedance. This impedance has two components: resistance and inductance per-unit length. The currently existing methods of analytical calculation of the internal impedance are based upon the approximations to keep the numerical stability and are limited to two layers made of different materials. This study presents the matrix approach of calculating the per-unit-length parameters of the multilayer wire with high accuracy. Due to the implementation of the modified scaled Bessel functions and the division onto additional sub-layers, the presented method is numerically stable for relatively thick conducting layers, even at high frequencies. The time of computations done by the presented method of internal impedance and required memory is much lower than in the case of the finite-element models.

Birefringence as a function of upper-cladding layers in polymeric arrayed waveguide gratings

We investigated on the variation of polarization-dependent wavelength shifts in birefringent-polymeric arrayed waveguide gratings (AWG) along the each step of forming a core layer and a multi-layered upper cladding in fabrication processes. We found that the polarization-dependent wavelength shift is a function of the number of sublayers with a positive offset value depending on the thickness of the first sublayer and a negative slope depending on the thickness of the additional sublayers, resulting in a polarization-insensitive AWG with proper values of the thickness and the number.

Developmental patterns defining morphological characters in spores of four species in Glomus

Spore differentiation sequences are defined and compared in different geographic isolates of four Glomus species to better define species-level morphological characters and to integrate these sequences into a model of spore ontogenesis in Glomales. Phenotypically discrete characters in spores of all four species originated as component parts of a spore wall. This spore wall differentiated in a linear sequence of new layers that formed concurrently in the wall of the subtending hypha. Species were separated into two groups that differed in structure of the spore and hyphal wall in the most juvenile stage: (i) a single mucilaginous layer in G. etunicatum and G. clarum and (ii) a mucilaginous layer together with a semiflexible hyaline layer in G. intraradices and G. claroideum. Differentiation in all species then is followed by synthesis of a laminate layer in the spore wall. It begins as a thin sublayer that increases in thickness with synthesis of additional sublayers. Spores of G. clarum diverge by forming a second pigmented laminate layer in the spore wall. Spores of G. claroideum form an additional thin flexible layer resembling those found in spores of Acaulospora, Entrophospora, and Scutellospora species except that it originates as an attachment of the subtending hyphal wall and thus is interpreted as another component of the spore wall. Stages of differentiation in Glomus are similar to those documented for Gigaspora (Gigasporaceae), except that number and diversity of layers are greater in both spore and subtending hyphal walls of the former. Character differences in development support the separation of Glomaceae and Gigasporaceae into separate suborders and further suggest the order Glomales may be polyphyletic.

Developmental Patterns Defining Morphological Characters in Spores of Four Species in Glomus

Spore differentiation sequences are defined and compared in different geographic isolates of four Glomus species to better define species-level morphological characters and to integrate these sequences into a model of spore ontogenesis in Glomales. Phenotypically discrete characters in spores of all four species originated as component parts of a spore wall. This spore wall differentiated in a linear sequence of new layers that formed concurrently in the wall of the subtending hypha. Species were separated into two groups that differed in structure of the spore and hyphal wall in the most juvenile stage: (i) a single mucilaginous layer in G. etunicatum and G. clarum and (ii) a mucilaginous layer together with a semiflexible hyaline layer in G. intraradices and G. claroideum. Differentiation in all species then is followed by synthesis of a laminate layer in the spore wall. It begins as a thin sublayer that increases in thickness with synthesis of additional sublayers. Spores of G. clarum diverge by forming a second pigmented laminate layer in the spore wall. Spores of G. claroideum form an additional thin flexible layer resembling those found in spores of Acaulospora, Entrophospora, and Scutellospora species except that it originates as an attachment of the subtending hyphal wall and thus is interpreted as another component of the spore wall. Stages of differentiation in Glomus are similar to those documented for Gigaspora (Gigasporaceae), except that number and diversity of layers are greater in both spore and subtending hyphal walls of the former. Character differences in development support the separation of Glomaceae and Gigasporaceae into separate suborders and further suggest the order Glomales may be polyphyletic.