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Copper oxides have some interesting photocatalytic properties and reasonably low price which makes them applicable as PN transistors. However, to obtain the best performance it is necessary to increase the specific working surface of materials which plays a key role in many applications. Furthermore, by ordered spacing and heterojunction formation it is possible to fabricate the systems with specific dedicated properties, like for example PN photovoltaic junction. The conducted research analyses the mechanical properties, stress distributions, and thermal stability of metal–oxide structures with such advanced geometries. Micro-perforation of thin Cu sheet was selected for the study, as it can both enhance the free surface of the substrate and decrease the number of sites of thermal stress occurrence. Both Cu-Cu2O and Cu-CuO layers were simulated using finite element analysis. The model based on fixed geometry of square shaped samples of dimensions of 156 × 156 mm was applied to thin metal plates holes-patterned covered on top by 1-3 μm thick oxide layers. On the other hand, the influence of plate thickness was found to be important in terms of structure durability. A good agreement between the simulation and the experimental data was achieved. The critical delamination temperature of c.a. 473-483 K was estimated for both oxide layers. The verification of the simulation/computation model was done by analyzing perforated and non-perforated Cu Electrolytic Tough Pitch (ETP) sheets. Two methods, FIB-TEM and surface scan using a profilometer, were selected. The first verified the decohesion of the oxide coatings from the metal support after exceeding the temperature of 523 K The issue that was also noticed is the susceptibility for peeling in the inner surface of the holes.

The development of powder metallurgy methods in recent years has caused traditional casting methods to be replaced in many industrial applications. Using such methods, it is possible to obtain parts having the required geometry after a process that saves both manufacturing costs and time. However, there are many material issues that decrease the functionality of these methods, including mechanical properties anisotropy and greater susceptibility to cracking due to chemical segregation. The main aim of the current article is to analyze these issues in depth for two powder metallurgy manufacturing processes: laser powder bed fusion (LPBF) and hot-pressing (HP) methods—selected for the experiment because they are in widespread use. Microstructure and mechanical tests were performed in the main manufacturing directions, X and Z. The results show that in both powder metallurgy methods, anisotropy was an issue, although it seems that the problem was more significant for the samples produced via LPBF SLM technique, which displayed only half the elongation in the building direction (18%) compared with the perpendicular direction (almost 38%). However, it should be noted that the fracture toughness of LPBF shows high values in the main directions, higher even than those of the HP and wrought samples. Additionally, the highest level of homogeneity even in comparison with wrought sample, was observed for the HP sintered samples with equiaxed grains with visible twin boundaries. The tensile properties, mainly strength and elongation, were the highest for HP material. Overall, from a practical standpoint, the results showed that HP sintering is the best method in terms of homogeneity based on microstructural and mechanical properties.

This work investigates the influence of process parameters on microstructure, adhesion of layers to the substrate and wear resistance of Ni/MoS2 micro- and nanocrystalline composite layers. Pure nickel coatings were also fabricated and tested for comparison. The layers were deposited by electrochemical reduction on pure A2 aluminum and on PA6 alloy. The layers were produced at a current density of 3 A/dm2 and a mixing speed of 400 rpm. The bath composition was also modified by the addition of saccharin and the disperse phase of molybdenum disulfide in the bath (2.5 and 5 g/l). Materials prepared in this way underwent structural investigations (using scanning electron microscopy and optical microscopy), a scratch test and tribological tests (using a ball-on-disc method). The results of the tests allowed to determine the dependence of the structure and properties of the produced coatings on the production parameters. The composition of the electrolyte affects the size of crystallites as well as the morphology and topography of the surface. The scratch test confirmed the good adhesion of the nickel and composite layers to the substrate. The best lubricating properties were shown by nanocrystalline coatings. The too high content of molybdenum disulfide in the bath caused an undesirable increase in the coefficient of friction.

International audience; Radon is one of the main potential sources of background radiation for any rare event experiments like neutrinoless double beta decay or dark matter experiments. The Radon Trapping Facility (RTF) installed in 2004 at the Modane Underground Laboratory (LSM) has been running for nine years providing radon-purified air at a level of 10 mBq m−3 for several experiments. The radon suppression principle is based on a radon physical adsorption using cooled compressed air at −55 °C pumped through a column filled with the K48 activated charcoal. After disassembling of the RTF, the 2.6 m high charcoal column has been divided into several layers in order to study with different techniques the dynamic adsorption coefficient (the K-factor) as a function of the depth and the radon spatial trapping profile by measuring the 210Pb activity. It has been demonstrated that after almost a decade of running, the K-factor of the activated charcoal remains constant except for the first few cm of the column. Furthermore, it has been demonstrated that the mass activity of 210Pb as a function of the depth of the charcoal column exhibits an exponential decay profile. The radon mean retention time τ R of (47.6 ± 1.2) days and the radon mean free path of (28.9 ± 0.4) cm have been derived and found to be consistent at 1σ with the ones obtained from the K-factor study, i.e. from a total independent measurement. The radon suppression factor of the RTF of has been also estimated with a value consistent at 2σ with the suppression factor measured during the RTF operation. Thus, this study has proven the capacity of the RTF to purify the LSM air from radon by more than three orders of magnitude during nine years of operation.

Mathematical modelling of single and consecutive dual - frequency induction surface hardening systems are presented and compared. The both models are solved by the 3D FEM-based professional software supported by a number of own numerical procedures. The methodology is illustrated with some examples of surface induction hardening of a gear wheel made of steel 41Cr4. The computations are in a good accordance with experiments provided on the laboratory stand.

Corrosion behaviour of carbon steel (K-55) in fracturing fluid was studied with a rotation cylinder electrode, under static and rotation conditions by means of several electrochemical techniques which are as follows: open circuit potential (OCP) decay, potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS). The corrosion rate was determined by weight loss measurements. The electrode surface after a prefixed immersion time was characterised by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results indicated that carbon steel showed anodic dissolution behaviour that increased under rotating condition. The cathodic polarisation current density also increased with the electrode rotation due to the increased oxygen diffusion on the electrode surface. Two different oxide layers were formed: a dark, thin layer of magnetite tightly adhering to the electrode surface, characterised by localised corrosion spots, and a porous reddish layer of poorly adhering hematite (Fe2O3) and maghemite (γ-Fe2O3). Under higher rotation rate, the developed oxide layer was not so stable, owing to the shear stress induced between the solution and the specimen surface, enhancing the corrosion rate.

A new RNAA procedure was developed for simultaneous determination of low levels of I and Mn in biological materials. The procedure is based on sample decomposition by alkaline-oxidative fusion in a mixture of Na2O2 + NaOH at 900°C followed by extraction of elementary iodine by chloroform. Subsequently, Mn is separated either by precipitation of hydrated MnO2 or by extraction of the Mn-diethyldithiocarbamate complex in chloroform. The accuracy of the RNAA procedure developed was proven by analysis of several low-level biological reference materials. Detection limits of I and Mn achievable in both institutes and the degree of interference for the Mn determination due to 56Fe(n,p)56Mn reaction with fast neutrons are discussed.

Rad iochemical neutron activation procedures using liquid -liquid extraction with tetraphenylarsonium chloride in chloroform from 1M HCl and solid extraction with ALIQUAT 336 incorporated in a polyacrylonitrile binding matrix from 0.1M HCl were developed for ac curate determination of rhenium in biological and environmental samples at the sub -ng . g –1 level. Concentrations of Re in the range of 0.1 to 2.4 ng . g –1 were determined in several botanical reference materials (RM), while in a RM of road dust a value of ~10 ng . g –1 was found. Significantly elevated values of Re, up to 90 ng . g –1 were found in seaweed (brown algae). Results for Re in the brown algae Fucus vesiculosus in which elevated 99 Tc values had previously been determined suggested possible competition bet ween Re and Tc in the accumulation process.

This study is concerned with the modification of titanium surface by plasma electrolytic oxidation (PEO) and hydrothermal treatment. The samples were oxidized in an electrolytic solution that contained calcium β-glycerophosphate and calcium acetate. Then, the specimens were hydrothermally heated at a temperature of 220 °C for 4 h using an autoclave. The chemical composition of the surface layers was examined by XPS. The morphology of the surface was observed by SEM-EDS. The crystalline phases were identified by XRD. The corrosion resistance was determined by the electrochemical methods in a simulated body fluid (SBF) at a temperature of 37 °C after various times of exposure in SBF. The oxide layers formed by PEO were porous, highly crystalline and enriched with Ca and P. After hydrothermal treatment, hydroxyapatite crystals precipitated on the surface. The results of electrochemical examinations show that the surface modification by PEO and hydrothermal treatment decreases the corrosion resistance of titanium.

Al 2 O 3 coatings were produced by the LPD method with the use of solid precursors of aluminium oxide. The coatings were deposited on non-heated substrates and on substrates heated from an external heat source at various geometries of the substrate/impulse plasma stream arrangement. Depending on the technological variant employed, the coatings obtained were composed of metastable or stable monotropic Al 2 O 3 phases. The process parameters also affected the morphology of the coatings. The IR, RS and XPS examinations of the atomic structure of the coatings, performed in the present study and in earlier investigations, have shown that the aluminium oxide coatings deposited from impulse plasma have a nanocrystalline amorphous structure. The phase composition and morphology of the coatings can be modified by heating the substrate in a stationary way during the IPD process, to a temperature of 500 K.

The influence of grains boundaries (GB) on the mechanical properties of polycrystals has been subject of extensive studies in the past and still attracts a great deal of attention. In the common approach, mechanical properties of polycrystals are referred to the distribution of so called coincidence grain boundaries (CSL boundaries). The aim of the present paper is to evaluate possible effect of the changes in the texture of a polycrystal on characteristics of the grain boundaries. Micrograined AISI type 316 austenitic stainless steel was used for this investigation. Specimens were annealed at 900 C and quenched in water. Mechanical test were carried out at a constant temperature of: 21, 450 and 700 C and at initial strain rate 1.67 {times} 10{sup {minus}4} s{sup {minus}1} up to uniform strain of 24%. Quantitative analysis was performed to characterize the initial texture and the textures after deformation at various temperatures. Conclusions were as follows: plastic deformation in tensile tests significantly changes crystal texture of polycrystals; changes in the texture induced by tensile deformation depend on the deformation temperature; the changes in the texture increase the number of special grain boundaries or more generally alter character of the grain boundaries.