High Sensitivity to Salinity-Temperature Using One-Dimensional Deformed Photonic Crystal

This paper aims to theoretically study the concept of a photonic salinity and temperature sensor according to a deformed one-dimensional photonic structure. The fundamental capability of the proposed sensor is studied. Simultaneously we search to optimize the thickness of the structure and to get the maximum salinity and temperature sensitivity. The structure is constructed by alternating layers of TiO2 and fused-silica P times. In the middle of the structure, a cavity containing seawater is inserted to measure its salinity and temperature. The transfer matrix method (TMM) is used to simulate the wave-transmittance spectra. It is shown that the quality factor (Q-factor) of the resonance peaks depends on the number (P) of layers. After that, the thickness of the layers is deformed by changing the deformation degree (h). The parameters P and h are optimized to get the maximal Q-factor with the minimal number of layers and structure thickness. The best sensitivity SS of the proposed salinity sensor is 558.82 nm/RFIU with a detection limit of 0.0034 RFIU. In addition, the best sensitivity ST of the designed temperature sensor is 600 nm/RFIU with a detection limit of 0.0005 RFIU.

Performance characteristics of steel 1.2842 after nitridation

The paper deals with the change in mechanical properties and wear of 1.2842 universal tool steel after plasma nitriding, which is widely used to produce cutting tools with good durability and low operating costs. Plasma nitriding was performed at a temperature of 500 °C for 10-hour period in a standard N2 /H2 atmosphere with 1:3 gases ratio. Microstructure, phase structure, thickness of a nitriding layer and surface roughness of samples were measured with optical microscopes and a profilometer. Verification of a chemical composition was carried out on the BAS TASMAN Q4 device. Wear resistance was measured on a universal TRIBOLAB UTM 3 tribometer, through a, “pin on disc“ method. The results of experiments have shown that plasma nitriding process, significantly improves the mechanical and tribological properties of selected materials.

Anodizing under conditions of oxygen activation of the inter-electrode gap

Structured alumina is currently used in a wide range of applications. Interest in a surface with a wear-resistant coating motivates creation of methods for high-speed oxidation with an increase in the thickness and hardness of the layer, with obligatory observance of environmental parameters and a decrease in the energy intensity of production. Considering the activity of aluminum towards oxygen, a very important aspect is the search for conditions to increase the natural oxide film to the level of functional significance. The generally accepted scheme of classical anodizing represents a closed system of an electrolytic cell, inside which the elements are activated in the interelectrode gap to the state of ionic excitation under the action of an electric field. The efficiency of interaction depends on the medium’s nature and variability of the volt-ampere parameters. This work proposes a different mechanism for intensifying the process. Oxygen is activated outside the electrolytic cell and in the allotropic state, in the form of ozone, is transmitted into the interelectrode gap. The phase composition, structure, thickness, and microhardness are investigated. The aim of the research is to establish the effect of ozone on the oxidation process.

Studying the Behavior of Reinforced Concrete Columns Confined by Steel Structure Under Eccentrically Loading

This research paper presents an analytical study of a number of Reinforced Concrete Columns models which have rectangular cross section and confined/unconfined by steel Structure of vertical angles and horizontal plates. Columns are subjected to centric and eccentric compression load. The objective is to know how far the bracing is effective in increasing the strength of these columns. This type of strengthening is considered better than the concrete Structure, Carbon Fiber Reinforced Polymer (CFRP) and other types because it has many features, easy and fast to be constructed. The study demonstrated that the bracing by steel Structure led to increase the strength in large ratios and had been clear that once the thickness of steel Structure is increased, the strength increases. And once the eccentricity is increased, the strength decreases and also the failure load. Keywords: reinforced concrete columns, bracing, steel structure, centriccompression, eccentric compression, steel structure thickness, strengtheningeffectiveness, failure load.

The Formation of Sulfide Scales on Carbon Steel in Saturated H2S

There are three contributing elements of corrosion of Carbon Steel in H₂ S environment: the effect of H2S on water chemistry; electrochemical reactions of the bare iron surface (both anodic and cathodic processes); and the formation and growth of corrosion product layers. The electrochemical reaction commonly contains three stages: first, the reactant transported from the solution (bulk) to the metal surface; then the transfer of the charge reaction on the surface, followed by the reaction product transported away from the iron surface to the bulk solution or the formation and development of the corrosion product which then can decrease the corrosion rate. Development of a robust corrosion model to predict the corrosion process in H2S requires a mechanistic understanding of all these elements. An experimental study was carried out to assess the corrosion of C-steel under open-circuit technique conditions and in solutions at several ranges of time and temperatures. The effect of film composition, morphology, structure, thickness, and ion- concentration of corrosion product films formed on pipeline Carbon Steel in an acid sour solution were examined. The electrochemical behavior of the filmed steel was measured, and the film properties assessed using a range of advanced techniques including Scanning Electron Microscopy (SEM), and Raman spectroscopy (RS). The data will be discussed in terms of film formation mechanisms.

Lake pushed out by 200 m³ rock avalanche (Zugspitze / Lake Eibsee, D) - New geophysical and sedimentological insights into interactive processes

<p>Rock avalanches destroy and reshape landscapes within only few minutes and are among the most hazardous processes on earth. Water in the travel path may accelerate the rock avalanche, with longer runouts as a result. So far no study has aimed at proving the existence of a paleolake pushed out by a rock avalanche and further analysing the interaction of the moving mass with the former lake. Especially for ancient long-runout mass movements this could be the key to explain exceptional runout lengths.</p><p>In this study at the Zugspitze / Eibsee rock avalanche we prove the existence of, and the impact onto a paleolake inside the rock-avalanche trajectories. We assume that there has been a paleo-Lake Eibsee which was displaced by the ~200 mio. m³ rock avalanche. Our approach shows a complementary application of geomorphological mapping (over ~5 km²) and Electrical Resistivity Tomography (ERT) measurements (8 profiles with in total ~9.5 km length), combined with sedimentological analysis in outcrops and drillings. The geoelectrical profiles give us up to ~120 m deep insights into the structure, thickness and distribution of the rock-avalanche deposits, the interactive processes with the lake water and sediments, and the paleotopography. Sediments exposed in outcrops show water-escape structures at the front of the rock avalanche. The data further allow for ERT-calibration at 7 different sites, where it is possible to distinguish materials (rock avalanche, bedrock, lake clay, mixed sediments) and interactive processes of the rock avalanche with the lake and substrate (bulldozing, bulging, overriding of secondary lobes). Here we show how complementary geophysical, geomorphological and sedimentological applications on terrestrial deposits provide detailed insights into multiple effects of impacting of a rock avalanche onto a lake.</p>

Structure Investigation of Titanium Metallization Coating Deposited onto AlN Ceramics Substrate by Means of Friction Surfacing Process

The article presents selected properties of a titanium metallization coating deposited on aluminum nitride (AlN) ceramics surface by means of the friction surfacing method. Its mechanism is based on the formation of a joint between the surface of an AlN ceramics substrate and a thin Ti coating, involving a kinetic energy of friction, which is directly converted into heat and delivered in a precisely defined quantity to the resulting joint. The largest effects on the final properties of the obtained coating include the high affinity of titanium for oxygen and nitrogen and a relatively high temperature for the deposition process. The titanium metallization coating was characterized in terms of surface stereometric structure, thickness, surface morphology, metallographic microstructural properties, and phase structure. The titanium coating has a thickness ranging from 3 to 7 μm. The phase structure of the coating surface (XPS investigated) is dominated by TiNxOy with the presence of TiOx, TiN, metallic Ti, and AlN. The phase structure deeper below the surface (XRD investigated) is dominated by metallic Ti with additional AlN particles originating from the ceramic substrate due to friction by titanium tools.

Structural optimization to maximize loss factor of embedded co-cured damping composite

The purpose of this study is to obtain the maximum loss factor of the embedded co-cure damping composite structure with the boundary condition of four edges clamped. To achieve this goal, the strain energy of each stress component is deduced using the Ritz method, and the loss factor of the structure is calculated. The present formulation is validated based on the results obtained using the finite element method. Finally, the law of loss factor variation with the change in structure thickness and layup angle is obtained. The results obtained show that the loss factor of the structure increases as the thickness of the structure increases; when the total thickness of the structure is constant, the loss factor increases first and then decreases, and there is an optimal value for the design; the optimal lay angle is pi/4.