Assessment of environmental pollution level caused by shipbuilding industry

The purpose of the paper was to create databases that would allow a proper assessment of the degree of marine pollution generated by shipyard industrial sector. The study was conducted over a period of three years, between 2015 and 2017. The parameters determined for the waters collected from the shipyard were within the maximum allowed limits according to the norms in force. However, values very close to the maximum allowable limit were observed in the case of groundwater for nickel, determined from the drilling located near the fuel depot in 2015 and chlorides determined from the drilling located near the galvanizing workshop, both in 2016 and in 2017. The analyzed parameters for the soil samples, collected from various sampling points and different depths, were below the value of the alert thresholds for less sensitive soils, according to Order 756/97. The databases created for this study can contribute as an incipient basis for the development of larger studies that include other industrial sectors as well as a longer evaluation period

3D Biomimetic Magnetic Structures for Static Magnetic Field Stimulation of Osteogenesis

We designed, fabricated and optimized 3D biomimetic magnetic structures that stimulate the osteogenesis in static magnetic fields. The structures were fabricated by direct laser writing via two-photon polymerization of IP-L780 photopolymer and were based on ellipsoidal, hexagonal units organized in a multilayered architecture. The magnetic activity of the structures was assured by coating with a thin layer of collagen-chitosan-hydroxyapatite-magnetic nanoparticles composite. In vitro experiments using MG-63 osteoblast-like cells for 3D structures with gradients of pore size helped us to find an optimum pore size between 20–40 µm. Starting from optimized 3D structures, we evaluated both qualitatively and quantitatively the effects of static magnetic fields of up to 250 mT on cell proliferation and differentiation, by ALP (alkaline phosphatase) production, Alizarin Red and osteocalcin secretion measurements. We demonstrated that the synergic effect of 3D structure optimization and static magnetic stimulation enhances the bone regeneration by a factor greater than 2 as compared with the same structure in the absence of a magnetic field

Variations in growth and reproduction measurements of Trachurus mediterraneus from the Romanian Black Sea Coast

International audienceAs the horse mackerel Trachurus mediterraneus (Steindachner, 1868) is one of the most exploited commercial species of the Black Sea fisheries, the knowledge of its different biological aspects related to growth and reproduction is highly important. This paper presents preliminary results of the analysis of morphological measurements (total length, total weight), Fulton relative body condition index, age, sex and degree of maturity of the horse mackerel population from the Romanian Black Sea coast. 563 individuals were collected between June and November in 2013, 2014, 2015 and 2018, from trawl and trap net catches. Their mean total length was 11.4 +/- 2.4 cm, their mean total weight was14.4 +/- 8.5 g and they had between 0 and 4+ years with a mean age of 1.7 +/- 1.1 years. The data analyses of their measurements highlighted significant temporal differences between years and months, but no differences occurred between areas and sexes. These results should contribute to a better knowledge of the biology of the horse mackerel and may help to improve the management of the stock of this species for sustainable fisheries

An Experimental Study on Nano-Carbon Films as an Anti-Wear Protection for Drilling Tools

Carbon thin films of 50–100 nm thickness were synthesized by Pulsed Laser Deposition in vacuum at different laser fluences from 2 to 6 J/cm2. The deposited films were characterized by Raman spectroscopy for compositional assessment, scanning electron microscopy for morphology/thickness evaluations, and X-ray reflectivity for density, thickness, and roughness determinations. The films were ~100 nm thin, smooth, droplet-free, made of a-C:H type of diamond-like carbon. The mechanical properties of synthesized films were studied by nanoindentation and adhesion tests. The films that were obtained at low laser fluences (2, 3 J/cm2) had better mechanical properties as compared to those synthesized at higher fluences. The mean values of hardness were around 20 GPa, while the friction coefficient was 0.06. The deposition conditions of carbon thin films that displayed the best mechanical properties were further used to coat commercial drills. Both uncoated and coated drills were tested on plates that were made of three types of steel: Stainless steel 304, general use AISI 572 Gr 65 steel (OL60), and AISI D3 tool steel (C120). All of the drill edges and tips were studied by optical and scanning electron microscopes. The coated samples were clearly found to be more resistant, and displayed less morphological defects than their uncoated counterparts when drilling stainless steel and OL60 plates. In the case of C120 steel, carbon coatings failed because of the high friction between drill and the metal plate resulting in tip edges blunting that occurred during processing