Micromechanical and Tribological Properties of Nanostructured Carbonitride Coatings Deposited by PVD Technique

Nanostructured smart coatings (NSC) based on the TiAlSi-CN composite structure elements were deposited using reactive high-power physical vapor deposition (PVD) technique. The advanced modular deposition system included up to 8 high-power magnetron sputtering devices (MSD) allowing operate them simultaneously and exceed power density of 120 W/cm2 within each device erosion zone. The novel designed NSC on bearing steel 100Cr6 substrates demonstrated enhanced mechanical and tribological properties comparably with bearing steel ones required for multifunctional high-tech applications. The deposited NSC containing TiAlSi-CN nanoparticles strengthened by elemental additives Cr and Nb exhibited microhardness as high as 2500 HV values in comparison with 750 HV of 100Cr6 steel substrates. Load-displacement curves obey Meyer’s power-law surprisingly well because power-trendline fitted ones by R-squared value of 0.9999 for all the film-samples. Tribological properties were measured under dry friction conditions between the bearing steel ball of Ø 6 mm and the film-samples’ flat surface. Coefficient of friction (CoF) ranges between 0.22-0.56 depending on a sample and load. Tribotracks worn under the friction indenter were too shallow to evaluate them by Mitutoyo profilometer SJ-500. Therefore, the wear rate was estimated as ball wear of the friction indenter.

Geologic Structure, Mineralogy, and Geochemistry of the Nerunda Gold Ore Field (Northern Transbaikalia)

—We consider the geologic structure of the Nerunda gold ore field located in the Nerunda–Mama ore district in northern Transbaikalia. Gold–quartz low-sulfide formation and ore-bearing carbonate-terrigenous strata and intrusive complexes are briefly described. An ore complex of beresite–listvenite metasomatites hosting carbonate–quartz veins and vein–veinlet zones is characterized. Two stages of ore formation have been recognized. Anomalous geochemical associations and the composition of ore mineralization typical of these stages have been established. Mineralogical and geochemical studies of gold-bearing metasomatites of the Nerunda ore field were carried out. The known geochemical and mineralogical search criteria used for the assessment of the erosion zone level of gold deposits were applied to the geologic conditions of the Nerunda ore field and the Nerunda–Mama gold ore district as a whole. The emphasis was made on the express assessment of the erosion zone level at the early stage of prospecting. We draw a conclusion about the gold potential of the poorly studied ore objects at depth and give guidelines for the following geological prospecting.

Geological feature clarification of the contact zone of Akhskaya and Cherkashinskaya formations on the example of Priobskaya area

The first phase of subcycle AC12 formation on the example of the southern part of the Priobskoye field is considered. The job is done based on 3d seismic and geological model complexing with the using log interpretation. The erosion zone that violates the original structure of the upper part of the deep-sea clay pack III of akhskaya formation by paleochannels was revealed. These erosions form lithologic traps, isolated from the top productive reservoirs of subcycle AC12.

The Debris Distribution Model for Removal Planning of an Urbanized Estuarine Complex

We checked the spatial pattern of debris stranding at Praia de Santos (Brazil) in the first hour after the peak of high and low tide in summer and winter. We recorded and counted 20 types of debris (natural and anthropogenic) in 6 transects arranged in 3 zones along the beach (deposition, transport, and erosion). Canonical Correspondence Analysis (CCA) showed that buoyancy was an essential property in distinguishing debris stranding behaviours. The erosion zone, closer to the estuary showed that many mollusk shells, ropes and rocks, while plastics, styrofoam and fiber nylon were in the deposition zone. Throughout the estuary, we inspected the beach, identifying sections of origin and accumulation associated with the circulation system and currents. We propose the removal and recycling of debris from accumulation sites near highways and urban systems.

Study of Erosion Behavior in Elbows Mounted in Series Using Computational Fluid Dynamics Method

To date, numerous studies using experimental methods or computational fluid dynamics (CFD) simulations to investigate erosion in elbows have been published. However, most of these studies focused on erosion caused by large particles flowing through a single elbow, whereas erosion due to small particles in elbows mounted in series is largely ignored. Studying erosion in elbows mounted in series is essential for improving the design of pipeline systems. In this paper, a CFD model is developed and validated against experimental data in the literature. The effects of both the connecting length (i.e., the distance between two elbows connected in series) and the elbow radius of curvature on erosion behavior were investigated using the verified model. In addition, the Dean number and Stokes number were used to investigate particle motion. The results show that erosion in the second elbow first decreases and then increases, as the connecting length increases, and the maximum erosion zone always occurs in the first elbow. However, when the number of elbows is increased to four, interestingly, the maximum erosion zone is located in the fourth elbow. The findings are valuable and provide guidance for designing novel pipeline systems that can mitigate erosion.

Dentale Implantatstrukturen aus CrCoMo/Near-dry EDM of CrCoMo dental implant structures

Die Funkenerosion wird in der Dentalindustrie zur Herstellung von hochpräzisem Zahnersatz aus CrCoMo eingesetzt. Dieser Beitrag stellt die Strategie und Technologie der halbtrockenen Funkenerosion von CrCoMo-Dentalbrücken vor. Als Dielektrikum kommt ein Wasser-Luft-Gemisch zum Einsatz, dass durch ein speziell entwickeltes Spülsystem durch die Kupfer-Werkzeugelektrode in die Erodierzone injiziert wird. Um die Effizienz des halbtrockenen Erodierprozesses zu erhöhen, werden die grundlegenden Zusammenhänge zwischen ausgewählten Prozessgrößen experimentell untersucht. Electrical discharge machining (EDM) is used in dental industry for the manufacturing of high-precision dentures from CrCoMo. This article presents the strategy and technology of near-dry EDM of CrCoMo dental bridges. A water-air mixture, which is injected through the copper tool electrode into the erosion zone by a specially developed flushing system is used as dielectric. In order to increase the efficiency of the near-dry EDM process, the basic relationships between the influencing process variables are investigated experimentally.