Surface binding energy and erosion coefficient on the nanoyttrium oxide under ionization irradiation

Using the conditions obtained from various simple and complex models, the energy of the surface area was calculated with the help of electronic structural transitions and thermo-sublimation approximations occurring in yttrium oxide nanoparticles irradiated with different energy deuterium ions. The depth of penetration of deuterium ions of different energies into the yttrium oxide sample, the rate of energy loss, and the energy of the surface area under the influence of temperature sublimation were determined using basic methods. In addition, the screening radius and erosion rate were determined using the Sigmund and Thomas–Fermi shielding function.

STUDY OF HIGH CHROME WHITE SHEEP DEPENDENCE ON CARBONE QUANTITY AND ABRAZIVE CONDITIONS

In addition to studying the properties of abrasive corrosion-resistant alloys, the article considers it important to study the abrasive corrosion-based effect of abrasive corrosion resistance of high-chromium white cast iron on the amount of carbon and the dependence of abrasive particles on carbide and particle dependence. At the same time, the spread of white cast iron with 1.5 - 30% Mo is higher, which makes it easier to spread the processed martensite cast iron. Açar sözlər: oil drilling equipment high chromium alloy, abrasive particle, diffusion resistance, hardness, erosion coefficient, abrasive conditions.

Polyethylene oxide matrix tablet swelling evolution: The impact of molecular mass and tablet composition

This article describes the designing of matrix tablets composed of polyethylene oxides (PEOs) with relative molecular masses of 1 × 106, 2 × 106, and 4 × 106. Percolation thresholds were determined for all of the selected PEO formulations (18, 16, and 12 %, m/m), taking into consideration excipients and tablet surface area which significantly increased the percolation threshold. Moreover, the robustness of the gel layer in PEO matrix tablets was evaluated by magnetic resonance imaging under various mechanical stresses (no flow, 12 mL min−1, and 64 mL−1 of medium flow). Correlations between the percolation threshold and gel thickness (R2 = 0.86), gel thickness and the erosion coefficient (R2 = 0.96) was detected. Furthermore, small-angle X-ray scattering of the selected PEOs detected differences in polymer molecular complexity at the nanoscale. Finally, the ratio of the heat of coalescence to the heat of fusion has confirmed the PEO molecular mass-dependent percolation threshold.

Multi-Hazard Susceptibility Assessment: Case Study – Municipality of Štrpce (Southern Serbia)

The Municipality of Štrpce (Southern Serbia) is an area located within the Šar Mountain National Park, and due to its great ecological importance, it was necessary to analyze the terrain susceptibility to the occurrence of natural hazards. The main goal of this research is to determine the locations that are most susceptible to natural hazards (earthquakes, erosion, torrential flooding, snow avalanches and forest fires) on the territory of the municipality of Štrpce. By utilizing the geographic information systems (GIS), the first step was to analyze seismic hazard for a 475-year return period (VII-VIII MCS for the observed area). The second step was to determine the intensity of erosion and total sediment production using erosion potential model (EPM). The mean erosion coefficient is quantified to 0.34, and the total sediment production is 131.795 m3/year. The third step was the analysis potential of torrential floods using the Flash Flood Potential Index (FFPI). This method indicated that 43.33% of the municipality is highly susceptible, and 18.86% is very highly susceptible to torrential floods. The Avalanches Potential Index (AVAPI) method was used for the fourth step which involved determining the area prone to the occurrence and movement of avalanches. It was determined that 9.1 km2 of the municipality area is susceptible to this type of hazard. The fifth step included the analysis of the terrain susceptibility to the occurrence of forest fires. More than half of the municipal area (52.4%) is highly susceptible, and 8.5% is very highly susceptible to forest fires. Following the five criteria analysis, weight coefficients were assigned for each of the analyzed parameters using the analytical hierarchy process (AHP), giving the result of the total susceptibility of the territory of Štrpce to natural hazards. Results indicated that over 45% of the municipality is highly or very highly prone to various natural hazards. This paper presents a significant step towards better understanding and more adequate management and mitigation of natural hazards not only in the investigated area, but on regional and national levels as well.

A Computationally Efficient Shallow Water Model for Mixed Cohesive and Non-Cohesive Sediment Transport in the Yangtze Estuary

In this paper, a computationally efficient shallow water model is developed for sediment transport in the Yangtze estuary by considering mixed cohesive and non-cohesive sediment transport. It is firstly shown that the model is capable of reproducing tidal-hydrodynamics in the estuarine region. Secondly, it is demonstrated that the observed temporal variation of suspended sediment concentration (SSC) for mixed cohesive and non-cohesive sediments can be well-captured by the model with calibrated parameters (i.e., critical shear stresses for erosion/deposition, erosion coefficient). Numerical comparative studies indicate that: (1) consideration of multiple sediment fraction (both cohesive and non-cohesive sediments) is important for accurate modeling of SSC in the Yangtze Estuary; (2) the critical shear stress and the erosion coefficient is shown to be site-dependent, for which intensive calibration may be required; and (3) the Deepwater Navigation Channel (DNC) project may lead to enhanced current velocity and thus reduced sediment deposition in the North Passage of the Yangtze Estuary. Finally, the implementation of the hybrid local time step/global maximum time step (LTS/GMaTS) (using LTS to update the hydro-sediment module but using GMaTS to update the morphodynamic module) can lead to a reduction of as high as 90% in the computational cost for the Yangtze Estuary. This advantage, along with its well-demonstrated quantitative accuracy, indicates that the present model should find wide applications in estuarine regions.

Investigation of Internal Erosion Susceptibility of Core Soil from Three Dams

Laboratory tests on internal erosion of cohesionless soils are often performed on cells submitted to a controlled seepage. The cell dimension depends on the grain size of tested soil and must meet the geometric and hydraulic scale requirements as regards to the modeled process. Three specimens collected from different zoned dams in Morocco were characterized for their geotechnical properties and dispersion sensitivity, and then submitted in two different cells to internal erosion (Hole Erosion Test) under controlled seepage. The erosion kinetics was measured, and soil classification was assessed as regards to the useful engineering guidelines. The results showed that specimen dimensions can affect the erosion parameters which are quite different from a cell to another. Even though the derived erosion coefficient values are different from the two testing cells, the classification of the three soils regarding the susceptibility to erosion, using engineering guidelines, indicated that the tested soils fall overall in neighboring erosion classifications. However, the soil involving the lower clay content provided the greatest resistance against internal erosion.

Mechanistic Mathematical Modelling of Pothole Development from Loss of Roadway Subsurface-Materials

In this paper, we developed a mechanistic mathematical model. It implies the engineering problem of pothole development on roadways. The issue involves internal erosion, a decline of subsurface materials, voids creation, depression, materials damage, and potholes’ appearance on the road’s surface. Our study aims to predict why, how, and when pothole develops from the loss of roadway subsurface materials. We reviewed many sources as our first method. It involved using and adapting the guiding principles for migrating particles upwards. We then changed specific parameters, formulated our model equation, solved it using the separation of variables, and then verified it. Observations from our review show that high traffic load pressure and water must be present on the road for particle migration to occur. They generate excess pore-water pressure that enables the movement of particles upwards. Particle relocation causes voids and dislocation of materials. Results show that an increase in time, cracks, soil erosion coefficient, and a decrease in the roadway’s height led to a rise in the number of materials lost from the pavement. Our study is relevant because it will better inform road managers and modelers on potholes, and they can-do preventive measures to avert total road failure.

Changes in Soil Erosion Intensity Caused by Land Use and Demographic Changes in the Jablanica River Basin, Serbia

The aim of this research is to determine the change in the spatial distribution of erosion intensity in the territory of the Jablanica River Basin in the period 1971–2016 caused by land use and demographic changes. The Erosion Potential Method (EPM) was used to quantify changes in erosion intensity and to estimate the total annual sediment yield. The research results show that the value of the erosion coefficient decreased from 0.432 in 1971 to 0.360 in 2016. Specific annual gross erosion in the Jablanica River Basin was 654.41 m3/km2/year in 1971, while in 2016 it was 472.03 m3/km2/year. The analysis of proportional changes was used to determine demographic changes and land use patterns in the basin area. In terms of the scale and intensity of the erosion process, three types and one sub-type of population dynamics of settlements and land use changes were distinguished, respectively: progressive, stagnant, regressive and dominant regressive. It was concluded that the results show the significance of demographic and land use changes in the control of the intensity of erosion. The Soil Erosion Map may be useful to planners and land use managers to take appropriate decisions for soil conservation in the basin.

Application of highly entropic coatings at simultaneous spraying of three cathodes in one cycle

In this work, we consider the application of highly entropic coatings while simultaneously sputtering three cathodes in a single cycle. The cathodes 12Cr15G9ND, Cu, Al were chosen as cathodes. The chemical composition of the cathodes was measured using a TESCAN MIRA 3 electron microscope. Using these cathodes, coatings were applied to polished samples of steel 45 in an NNV-6.6 I1 vacuum ion-plasma apparatus. The measurement was carried out using a MIRA 3 scanning electron microscope, an HVS-1000A microhardness tester, and a tribological research facility. SEM images show that with an increase of ×5000 or more, the droplet phase is clearly detected. The maximum size of the droplet phase reaches 12.0 μm with a variety of morphometric parameters varying, for example, in a geometry coefficient K from 0.8 to 1.0. Analysis of the coating at high magnifications (×7000 and ×20,000) without the droplet phase showed that the grain sizes of the coating are as follows: minimum — 0.23 microns, maximum — 0.65 microns (average of about 0.47 microns); while the coating structure is homogeneous. The analyzed type of structure refers to the zone of the so-called «competing texture», when a dense nanocrystalline structure is present in the lower region of the film, and a columnar structure is above it. The results of this study allow us to conclude that the simultaneous deposition of deposited cathodes of various metals (especially composite) in principle allows to obtain highly entropic coatings. Two points must be taken into account here: firstly, the number of atomized cathodes must be increased; secondly, it is necessary to take into account the values of the erosion coefficient for the cathodes used so that the atomized fluxes are equimolarly proportional. Measurements of coatings showed that the microhardness of Cu+Al+12Cr15G9ND is not inferior to ordinary steels, but of course it lags behind nanostructured coatings (30–50 GPa). The proposed coatings have antifriction properties of 3 or more times and can be used in tribological pairs.

Estimation of Sediment Yield and Maximum Outflow Using the IntErO Model in the Sarada River Basin of Nepal

Soil erosion is a severe environmental problem worldwide as it washes away the fertile topsoil and reduces agricultural production. Nepal, being a hilly country, has significant erosion disputes as well. It is important to cognise the soil erosion processes occurring in a river basin to manage the erosion severity and plan for better soil conservation programs. This paper seeks to calculate the sediment yield and maximum outflow from the Sarada river basin located in the western hills of Nepal using the computer-graphic Intensity of Erosion and Outflow (IntErO) model. Asymmetry coefficient of 0.63 was calculated, which suggests a possibility of large floods to come in the river basin in the future whereas the maximum outflow from the river basin was 1918 m³ s−1. An erosion coefficient value of 0.40 was obtained, which indicates surface erosion of medium strength prevails in the river basin. Similarly, the gross soil loss rate of 10.74 Mg ha−1 year−1 was obtained with the IntErO modeling which compares well with the soil loss from the erosion plot measurements. The IntErO model was used for the very first time to calculate soil erosion rates in the Nepalese hills and has a very good opportunity to be applied in similar river basins.