In the current context of sustainability management and energy insecurity, amplified by the military instability determined by the war between Russia and Ukraine, and the increasingly frequent occurrence of a series of plausible scenarios for disasters or energy blackouts worldwide, this work is a real and applicable model for regional states that would like to critically analyze the situation of their energy security through identifying all the plausible risk scenarios targeting the energy critical infrastructures. The study has identified and assessed two of the most plausible risk scenarios (a natural disaster and a terrorist attack) in the case of a strategic power substation of 220 kV, 400 kV, or 750 kV undergoing a blackout effect. After having assessed the risks, the safety strategy for Romania’s national power system has been elaborated together with the safety strategy for the European Power system-ENTSO-E (European Network of Transmission System Operators for Electricity). The results of the study match other specialized works from different European countries and might represent a model for other types of energy safety risk assessments and for other types of critical infrastructures that are vital for the modern European society and for sustainability management.
An usual material, EN-GJL-250 cast iron, used for automotive braking systems, was covered with a ceramic material (105NS-1 aluminium oxide) using an industrial deposition system (Sulzer Metco). The main reason was to improve the corrosion and wear (friction) resistance properties of the cast-iron. Samples were prepared by mechanical grinding and sandblasting before the deposition. We applied two and four passes (around 12–15 µm by layer) each at 90° obtaining ceramic coatings of 30 respectively 60 µm. The surface of the samples (with ceramic coatings) was investigated using scanning electron microscopy (SEM), dispersive energy spectroscopy (EDS) and X-ray diffraction (XRD). Scratch and micro-hardness tests were performed using CETR-UMT-2 micro-tribometer equipment. The better corrosion resistance of the base material was obtained by applying the ceramic coating. The results present a better corrosion resistance and a higher coefficient of friction of the coated samples.
The effectiveness of the audit is conditioned by the systematic nature of the analyses and their periodicity. In this respect, the work of internal auditors must be coherent, continuous, and professional. These conditions can be met only if the activity is organized as a permanent system, which has its objectives and has resources (human, material, and financial), as well as adequate tools (audit method) corresponding to the activities carried out within the hydro-construction companies. The methodology for assessing the occupational safety status specific to companies in the field of hydrotechnical constructions was tested at the economic operators within SC HIDROCONSTRUCȚIA SA Bucharest. Thus, from the observation made based on the two calculation formulas’ application, it can be appreciated that the weighted amount more clearly and objectively reflects the existence of problems in achieving safety and health at work, thus constituting the result of a cautious approach, as opposed to the arithmetic mean formula, which leads to a result that tends to overestimate the value of the assessment. Additionally, the security risk determination in the field of occupational security at the economic operators was performed, according to the procedure of applying the method, based on the Gumbel probability function associated with insecurity, and the accuracy of various estimates on risk predictors was ensured by using the Kolmogorov–Smirnov statistical verification test in order to determine the confidence interval of the forecast results.
Phosphate coatings are one of the most important methods in preventing metal corrosion, especially iron alloys. The high interest in this method for industrial applications is mainly due to the low costs associated with the phosphating solution component and technological process. Considering this aspect and the advantages offered to the materials (corrosion resistance, good adhesion, wear resistance), this study evaluates the potential of using the phosphate coating method in health and safety applications. Therefore, the deposition of a layer of zinc phosphate on the steel surface used in the manufacture of components for personal protective equipment was approached. Firefighters, during rescue/evacuation operations, use protective equipment for fall arrest, whose accessories (hooks, carabiners) are made of steel. Due to the low corrosion resistance property of carbon steel, these accessories must be replaced frequently. This paper aims to analyze the possibility of improving the corrosion resistance of carbon steel in a fire extinguishing solution. Accordingly, the electrochemical behavior of two different types of coatings was studied by electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM). In the literature, different corrosion evaluating methods or systems have been considered, and up until now, there has been no previous study to have approached the corrosive behavior of C45, phosphate C45, and painted phosphate C45 immersed in fire extinguishing solution.
The article presents the theoretical and practical research results regarding the development of the IT and methodological infrastructure for assessing the parameters which define explosive substances. The software us intended for estimating, based on the chemical composition of substances, parameters which define such substances (detonation velocity, detonation energy, detonation pressure etc.), as well as for determining the probability of explosion. EXPLO5 is a specialized software which allows to solve thermo-dynamic equations between different reaction products in order to determine the balance composition, having incorporated a filtering algorithm for estimating Jones-Wilkins-Lee (JWL) state equations coefficients which are used for calculating the detonation energy of explosives. For the proper performance of pilot tests of numerical simulations upon certain representative types of explosives (civil use explosives and double-use explosives: civil and military) there have been taken into account the special characteristics of EXPLO5 provided by the EOS BKW (BKW standard with set of BKWN constants and BKW EOS modified with the set of constants and volumes BKWN-M) and EXP-6 EOS function which is based more on theoretical concepts.
A new non-sparking metallic material, Cu-Ti, with applications in potentially explosive environments is proposed as an alternative to CuBe, to reduce the processing and toxic effects of Be. Using high-purity Cu and Ti materials, a Cu (~3–4 wt%) Ti alloy with good chemical and structural homogeneity was fabricated in an induction furnace under an Ar atmosphere. The hot-rolled material was tested in an explosive gas mixture (10% H2 or 6.5% CH4) under extremely severe wear tests for 15,000 cycles, and no hot sparks were produced to ignite the medium. The material was investigated as hot-rolled plates (600 s at 950 °C and 10% reduction). The microstructures and surface of the wear test samples were investigated by light optical microscopy (LOM) and scanning electron microscopy (SEM). The chemical compositions were determined by energy dispersive spectrometry (EDS). The corrosion behavior was studied using electrochemical techniques: open-circuit, linear, and cyclic potentiometry in saline electrolyte solutions. The mechanical properties, such as microhardness and friction coefficient, were determined using UMT equipment. The results showed that the alloy is suitable for applications requiring non-ignition properties, with good hot rolling deformability and chemical composition homogeneity. Regarding the corrosion analysis and mechanical properties of the experimental CuTi alloy, minor differences were observed between the cast- and hot-rolled material.