Structure and mechanical properties of diamond-like carbon (DLC) coatings doped with silicon

This paper reports the study of silicon-doped diamond-like carbon coatings a-C:H:Si prepared by Plasma-Assisted Chemical Vapour Deposition (PACVD) on 100Cr6 steel. Surface morphology and elemental composition were determined with the use of Scanning Electron Microscopy (SEM) / Energy Dispersive Spectroscopy (EDS). Surface topography measurements were performed using Atomic Force Microscopy (AFM). The scratch test assessment of the influence of a-C:H:Si coatings on mechanical properties was based on the measurements of nanohardness and adhesion to the substrate. The results show that silicon-doped diamond-like carbon coatings a-C:H:Si are characterized by a uniform surface structure, high hardness and good adhesion to the substrate

Diamond-like carbon (DLC) coatings on roller bearing elements of belt conveyors

The aim of the study was to analyse the anti-wear diamond-like carbon (DLC) coatings produced by Plasma-Enhanced Chemical Vapour Deposition. The DLC coatings were deposited on the rings of rolling bearings operating in belt conveyors. The service life of the bearings was 1,5 years. The bearings were exposed to harsh environmental conditions. After the disassembly of the bearings, the influence of the coatings on the improvement of tribosystem characteristics was assessed. Characterization of the bearing geometry was carried out using an optical surface profilometer. The use of diamond-like coatings on rolling bearings extended the tribosystem service life in industrial conditions threefold

Introduction to the Special Issue on "Family migration processes in a comparative perspective"

This paper provides an introduction to this Special Issue on "Family migration processes in a comparative perspective". Following an introduction to the topic, we provide summaries of the papers in this Special Issue and discuss afterwards some overarching theoretical perspectives. This Special Issue contains papers that explore how family lives and intimate relationships are constituted and re-constituted under conditions of transnationality. The authors of the contributing papers, although they have followed very different theoretical and methodological paths, underscore the effect of conducting and facilitating family life and couple relationships during or after an international migration process. They show that the couples and multigenerational families in transnational contexts are constantly undergoing processes of constitution, negotiation, and reconstitution. We conclude that future research should shift from focussing solely on the individual to examining couples and families, and it should adopt dynamic, rather than static perspectives when studying family migration

Assessment of the properties of diamond-like carbon coatings (DLC) used in the lime industry

The aim of the study was to analyze the properties of diamond-like carbon coatings - DLC in machines operating in the lime industry. DLC coatings were deposited by the Plasma-Enhanced Chemical Vapor Deposition PECVD method on 100Cr6 steel samples. Characterization of the geometric structure of samples was carried out on an optical profilometer. The friction junctions were tested in harsh conditions, i.e., corrosive environment and high temperature. The tribological tests were performed using a sliding ball-on-disc tribological tester. The static contact angle for selected lubricants was measured using an optical tensiometer. The summary presents the possibilities of using diamond-like coatings in selected friction junctions in the lime industry

Assessment of the properties of diamond-like carbon coatings (DLC) used in the lime industry

The aim of the study was to analyze the properties of diamond-like carbon coatings - DLC in machines operating in the lime industry. DLC coatings were deposited by the Plasma-Enhanced Chemical Vapor Deposition PECVD method on 100Cr6 steel samples. Characterization of the geometric structure of samples was carried out on an optical profilometer. The friction junctions were tested in harsh conditions, i.e., corrosive environment and high temperature. The tribological tests were performed using a sliding ball-on-disc tribological tester. The static contact angle for selected lubricants was measured using an optical tensiometer. The summary presents the possibilities of using diamond-like coatings in selected friction junctions in the lime industry

Hydroelastic solitary waves in deep water

The problem of waves propagating on the surface of a two-dimensional ideal fluid of infinite depth bounded above by an elastic sheet is studied with asymptotic and numerical methods. We use a nonlinear elastic model that has been used to describe the dynamics of ice sheets. Particular attention is paid to forced and unforced dynamics of waves having near-minimum phase speed. For the unforced problem, we find that wavepacket solitary waves bifurcate from nonlinear periodic waves of minimum speed. When the problem is forced by a moving load, we find that, for small-amplitude forcing, steady responses are possible at all subcritical speeds, but for larger loads there is a transcritical range of forcing speeds for which there are no steady solutions. In unsteady computations, we find that if the problem is forced at a speed in this range, very large unsteady responses are obtained, and that when the forcing is released, a solitary wave is generated. These solitary waves appear stable, and can coexist within a sea of small-amplitude waves

Steady dark solitary flexural gravity waves

The nonlinear Schrödinger (NLS) equation describes the modulational limit of many surface water wave problems. Dark solitary waves of the NLS equation asymptote to a constant in the far field and have a localized decrease to zero amplitude at the origin, corresponding to water wave solutions that asymptote to a uniform periodic Stokes wave in the far field and decreasing oscillations near the origin. It is natural to ask whether these dark solitary waves can be found in the irrotational Euler equations. In this paper, we find such solutions in the context of flexural-gravity waves, which are often used as a model for waves in ice-covered water. This is a situation in which the NLS equation predicts steadily travelling dark solitons. The solution branches of dark solitons are continued, and one branch leads to fully localized solutions at large amplitudes

The Use of Airborne LiDAR in Assessing Coastal Erosion in the Southeastern USA

Changes in sea level along the coastal southeastern United States (U.S.) influence the dynamic coastal response. In particular, the Southeast Coastal Network (SECN) of the National Park Service (NPS) has exhibited evidence of fluctuations in sea level which caused coastal erosion. Airborne LiDAR acquired from NOAA for Fort Matanzas National Monument, Fort Pulaski National Monument, Charles Pinckney National Historic Site, and Cape Lookout National Seashore were analyzed to identify changes in both elevation and the spatial volume of unconsolidated sedimentary material in the coastal southeast over time. Areas that exhibited an increase (deposited material) or decrease (eroded material) in elevation were mapped across the study area from 2006 to 2018. Results indicate a quasi-cyclic process where unconsolidated sediment distribution and the morphodynamic equilibrium changes with time. The coastal zones are steadily oscillating between the process of erosion and deposition affecting the coastal geomorphological dynamic. The use of LiDAR for evaluating coastal sustainability and resiliency due to this environmental phenomenon is clear