Literatura científica selecionada sobre o tema "NaCl solid deposit"

A comprehensive corrosion investigation of pure Fe in an environment of solid sodium salt deposit (i.e., NaCl or Na2SO4) with mixtures of H2O and O2 at 500°C was conducted by mass gain measurement, X-ray diffraction (XRD), scanning electron microscope (SEM), potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS). The results showed that corrosion rates were accelerated with solid NaCl or Na2SO4 deposit due to their reaction with the formed protective scale of Fe2O3 and subsequently resulted in its breakdown. The corrosion rate of pure Fe with solid NaCl is higher than that with solid Na2SO4 because of the lower activation energy (Ea) for chemical reaction of Fe in solid NaCl+H2O+O2 (i.e., 140.5 kJ/mol) than that in solid Na2SO4+H2O+O2 (i.e., 200.9 kJ/mol). Notably, the electrochemical corrosion rate of pure Fe with solid NaCl deposit, 1.16×10−4 A/cm2, was a little lower than that with solid Na2SO4 deposit.

Titanium alloys are widely used in aerospace applications due to their good ratio of weight versus mechanical properties. When exposed to air at 560°C, Ti6242S titanium alloy presents very good oxidation resistance: a very thin oxide layer forms at its surface and oxygen dissolution inside the metallic material is rather limited. However, in real functioning conditions of the plane, near seas or oceans, the atmosphere contains NaCl, that can crystallise at the surface of hot parts. An active corrosion mechanism is established in these conditions, with catastrophic effect on the material behaviour at high temperature: very thick and brittle oxide scales and very important damaging of the metal outer part. Another issue is the formation of Na2SO4 specie by reaction of NaCl with kerosene combustion gases (SO2/SO3), leading to mixed NaCl/Na2SO4 deposits. The effect of exposure conditions on the mechanical properties of titanium alloy Ti6242S was evaluated through tensile tests performed on the raw alloy and after oxidation in air at 560°C of the specimens: without any deposit, with NaCl solid deposit, with NaCl/Na2SO4 solid deposit. The evolution of mechanical properties was interpreted in connexion with the microstructural modifications that occur during the high temperature ageing.

The Wushan copper polymetallic deposit is located in the Tongbai-Dabie orogenic belt in central China. Two small granitoid stocks (Donggushan and Xigushan) occur in the deposit, which is next to the largest Qijianfeng Granite Complex in the Suizao area. The mineralization of Wushan copper polymetallic deposit is mainly composed of ore-bearing quartz veins and quartz stockworks. Two hydrothermal stages are identified as the quartz-sulfide stage (early stage) and the barren quartz stage (late stage). A detailed petrographic study shows four types of fluid inclusions in quartz, including the aqueous fluid inclusions (L+V/V+L), the aqueous-carbonic fluid inclusions (L+V+CO2), the pure carbon dioxide fluid inclusions (pure CO2), and the daughter mineral-bearing multiphase fluid inclusions (S). The daughter mineral-bearing multiphase fluid inclusions (S) are further divided into three subclasses according to their different solid mineral assemblages, including (1) S1: L+V+Hal, (2) S2: L+V+CO2+S (chalcopyrite), and (3) S3: L+V+S (calcite, chalcopyrite, and hematite)±Hal. A laser Raman spectroscopic analysis shows that the main components of fluid inclusions are water and carbon dioxide. The solid minerals of the S-type fluid inclusions include halite, calcite, chalcopyrite, and hematite. The homogenization temperatures of fluid inclusions are 377 to 468°C for the early stage, with a salinity of 11.1 to 34.1 wt.% NaCl equivalent (11.1 to 17.4 wt.% NaCl equivalent and 28.4 to 34.1 wt.% NaCl equivalent, respectively) and an estimated pressure of 89 to 137 MPa. The homogenization temperatures of fluid inclusions in the late stage are 267 to 380°C with salinity of 7.0 to 12.1 wt.% NaCl equivalent and an estimated pressure of 46 to 115 MPa. Therefore, the temperature, salinity, and pressure of the fluid show a decreasing trend from the early to the late stage. In the early stage, the fluid is immiscible, which leads to the precipitation of sulfides. Pyrite shows a δ34S of approximately 0 (-1.8 to +3.4‰), and chalcopyrite also shows a similar δ34S of approximately 0 (+1.5 to +2.4‰), which indicates that the sulfur in the ore-forming fluid is mainly derived from deep-seated magma. Combined with C-H-O isotopic compositions, the initial ore-forming fluid is likely magmatic water, but with the addition of meteoric water in the late stage. By comparing with the typical characteristics of magmatic hydrothermal vein deposit and orogenic deposit related to shear zones, we suggest that the Wushan copper polymetallic deposit is most likely a magmatic hydrothermal vein deposit, which is of great significance for the further exploration work in the Wushan and surrounding areas. This new finding also fills the gap that no magmatic hydrothermal vein type Cu deposits have been found in the Suizao area or even in the Qinling-Dabie orogenic belt in central China.

The mineral and chemical compositions of ores from the Corrida epithermal Au-Ag deposit (Chukchi Peninsula, Russia) were studied using the optical and scanning electron microscopy with X-ray energy-dispersion microanalysis. The deposit was formed at the time close to the period when the basic volume of acid magmas had been emplaced within the Okhotsk–Chukotka belt (84 to 80 Ma). The Au–Ag mineralization is distinguished with Au-Ag sulphides and selenides (uytenbogaardtite-fischesserite solid solution, Se-acanthite, S-naumannite) and Ag halides of the chlorargyrite-embolite-bromargyrite series. The ores were formed in two stages. Using microthermometric methods, it has been established that the ore-bearing quartz was formed in the medium-temperature environment (340–160 °C) with the participation of low-salt (3.55 to 0.18 wt.% NaCl eq.) hydrotherms, mostly of the NaCl composition with magnesium, iron and low-density СО2. According to our results of thermodynamic modeling at temperatures from 300 to 25 °C and data on mineral metasomatic alterations of the host rocks, the Au-Ag-S-Se-Cl-Br mineralization was formed at decreasing temperature and fugacity of sulphur (logƒS2 from −6 to −27), selenium (logƒSe2 from −14 to −35), and oxygen (logƒО2 from −36 to −62), with near-neutral solutions replaced by acid solutions. Analysis of the obtained data shows that the Corrida refers to the group of the LS-type epithermal deposits. This deposit is a new example of epithermal deposits with significant quantities of Au–Ag chalcogenides (acanthite, uytenbogaardtite, fischesserite, naumannite and others).

The hot corrosion behavior of titanium alloy and AlCuFeCr quasicrystalline coating on titanium alloy in the presence of a solid mixture of NaCl and Na2SO4 deposit at 700°C was studied. The result shows that weight-gain kinetics for titanium alloy exhibited a linear rate law, while the kinetics of AlCuFeCr quasicrystalline coating displayed parabolic growth rate. The corrosion resistance of the titanium alloy was improved by applying the AlCuFeCr quasicrystalline coating. The corrosive oxide morphology formed on titanium alloy was porous. For AlCuFeCr quasicrystalline coating with the mixture of NaCl and Na2SO4 deposit, the scale formed on the coating surface was compact and uniform. Oxide formed on the surfaces of Al-Cu-Fe-Cr quasicrystalline coatings after hot corrosion consisted of Al2O3.

There are many celestine deposits and mineralization points in the Huayingshan ore district which form the largest strontium resource base in China. Among these celestine deposits, the Yuxia and Xinglong are two of the larger deposits. Previous studies have displayed different views on the genesis of the celestine deposit in the Huayingshan ore district. In this study, we conducted field obversions, geochemistry, and fluid inclusion studies to investigate the sources of ore-forming matters and the metallogenic mechanism of the celestine deposit. Four types of fluid inclusion (FI), namely PL (pure liquid FI), PV (pure vapor FI), L-V (liquid-vapor two-phase FI), and L-V-S (liquid-vapor-solid three-phase FI) have been identified in celestine from different types of ore in the Xishan anticline. The ore-forming fluids belong to the NaCl-H2 O system with moderate to low temperature (190–220 °C) and moderate salinity (5–9 wt%, NaCl equiv.). Different types of ores were formed by the same period of hydrothermal activity, which is supported by the results of the microthermometer study. Geological, thermometric data, and published hydrogen and oxygen isotope results indicate that the hot brines associated with mineralization mainly originated from meteoric water and some of diagenetic fluid. The Sr (87Sr/86Sr = 0.7076–0.7078) and S (δ34S = 36.4–39.0) isotope values of celestine are consistent with those of the Jialingjiang Formation, indicating that ore metals in hot brines were predominantly derived from that formation. In situ analysis of celestine shows that there is a strong negative correlation between Sr and CaO (R2 = 0.95) and combined with mineralogical and isotope geochemical evidence, we concluded that the precipitation mechanism of celestine is the replacement of gypsum with Sr-rich hot brines. Based on the above research and the classification of celestine deposit type, we classified the celestine deposits in Huayingshan as being of hydrothermal type. The formation of celestine deposits can be divided into three periods: (1) evaporation period, forming the source bed; (2) hydrothermal activity period, forming celestine by replacement of gypsum with Sr-rich hot brines; (3) supergene period, where meteoric water dissolves orebodies and strontianization occurs.

Uranium can be found in the Earth’s crust in different reservoirs, with igneous rocks being the primary source of this element from which many types of secondary deposits are formed. Fluorspar deposits generally do not contain uranium, but in some cases, fluorite can carry both uranium in solid solutions and inclusions of uranium minerals. We studied the concentration (ICP-MS), composition (electronic microprobe), and spatial distribution (microscopy and auto-radiography) of elemental uranium and uranium minerals at different scales (microscopy and auto-radiography in fluorite from the La Azul fluorspar deposit (Taxco, Mexico) to assess the origin of uranium and its significance in this ore deposit. Auto-radiography images with the CR-39 detector were found to be impressive in their ability to elucidate uranium distribution at the millimeter scale. The limit between the solid solution of elemental uranium in natural fluorite and the appearance of uranium oxides as inclusions appeared to be between 20 μg g−1 and 40 μg g−1 bulk uranium concentration in this fluorspar ore. The maximum concentration of U in fluorite from the La Azul deposit was about 100 μg g−1. Using Raman spectroscopy and microprobe analysis, we identified the micro-inclusions of uranium minerals as uraninite (of the pitchblende variety); its composition suggested a hydrothermal origin for this fluorspar deposit. We also calculated a chemical age that can be compared with the previously published regional geology and isotopic (U-Th-Sm)/He ages in fluorite. Micro-thermometric studies of fluid inclusions were carried out in different samples of uranium-rich fluorite to identify the nature and origin of the mineralizing fluid and the precipitation mechanisms of uranium minerals. We concluded that the uranium-rich fluorite precipitated in the initial phases of mineralization from a reducing fluid, with low salinity (<8% NaCl eq.) and an intermediate temperature (110–230 °C), and that the presence of organic compounds and sulfides (mainly pyrite) favored the simultaneous precipitation of uraninite (pitchblende variety) and fluorite.

AbstractThe compositions of fluid inclusions hosted in emerald and quartz (the Maria deposit, Mozambique) were studied using microthermometric and Raman microprobe techniques. The fluid inclusions in the emerald contain fluids within the Na-Ca-Mg-(HCO3)−-(CO3)2−-Cl-H2O system saturated in carbonic acid brines. Nahcolite is a main daughter solid phase within the fluid inclusions. The mean nahcolite and NaCl contents are 25 and 5 wt.%, respectively. Mg-calcite, magnesite, calcite and aragonite are also identified as daughter phases in the fluid inclusions. Many fluid inclusions show necked-down appearance. Groups of nahcolite crystals often make up ∼50 vol.% of necked-down inclusions. It seems that zones of fluid inclusions with numerous birefringent solid phases are distinctive of the Maria emerald deposit. The likely conditions of emerald growth are 400 < T < 500°C and 3 < P < 4 kbar.

Microscopic examination was used to begin investigating the changes in geosynthetic clay liner (GCL) specimens that had been hydrated with two separate solutions: pure water and a 50 percent concentration NaCl solution. After already being hydrated with NaCl aqueous solution, the GCL samples were examined under an electron microscope. Even though the treated GCL samples’ surfaces mirrored those of the untreated GCL, a crystal deposit was found there. It was found that the bentonite particles in the GCL sample appeared more solid after being hydrated with distilled water as opposed to the NaCl solution using a scanning electron microscope (SEM). It seems that wetting the salt solution decreases the bentonite particles’ tendency to swell. Additionally, it was demonstrated by the energy-dispersive X-ray spectrometer (EDS) data that distilled water hydration had no impact on the distribution of the elements identified in the GCL samples. On the other hand, the presence of bound chlorine demonstrated that the bentonite particles had absorbed the NaCl solution. The hydrated GCL sample’s hydraulic conductivity showed some variation as well.

Morphological variations of geosynthetic clay liner (GCL) samples, hydrated with two different permeates, distilled water and NaCl solution (100 mM concentration), were observed in detail using microscopic analysis. After the GCL samples were hydrated with the NaCl solution, they were observed with an optical microscope. While the surface of the treated GCL samples was similar to the surface of the untreated GCL, a crystal deposit was found on the surface of the treated samples. Using a scanning electron microscope (SEM), a more solid appearance was observed for the bentonite particles contained in the GCL after the sample was hydrated with distilled water in comparison to the GCL sample that was hydrated with the NaCl solution. It appears that salt solution hydration results in less swelling of the bentonite particles. Furthermore, the energy-dispersive X-ray spectrometer (EDS) results showed that distilled water hydration had no effect on the distribution of the elements contained in the GCL samples. However, bound chlorine was observed, which demonstrated that the bentonite particles had absorbed the NaCl solution. In addition, changes in the hydraulic conductivity of the hydrated GCL samples were also observed.

Les matériaux à gradient de composition présentent de nombreux avantages et notamment celui d’adapter localement le matériau en fonction de la sollicitation perçue par la pièce tout en limitant les risques d’incompatibilités entre les matériaux. Ce travail de thèse s’est concentré sur la réalisation d’un système de matériaux à gradient de composition par procédé Laser Metal Deposition-powder à partir d’un substrat en acier faiblement allié jusqu’à un alliage 625. Ce système multi-matériaux devant présenter une bonne tenue à la corrosion à haute température, son comportement à 800 et 650°C sous air de laboratoire, en absence ou en présence d’espèces chlorées, a été étudié.La caractérisation du système à gradient, dans un état brut de fabrication a révélé différentes microstructures et phases en présence dans les différentes régions du gradient. Lors de vieillissements à 800°C, des évolutions métallurgiques ont été mises en avant, notamment au niveau de l’alliage 625, avec la précipitation de la phase δ.La résistance à l’oxydation du système a été étudiée sous air de laboratoire à 800°C jusqu’à 2 500 h. Une cinétique parabolique liée à la formation de couches protectrices de chromine a été mise en avant. La présence d’un dépôt de NaCl accélère de manière catastrophique la dégradation de l’alliage 625. Dans ce cas, les couches de produits de corrosion sont très épaisses, très fissurées ou écaillées, composées majoritairement de NiO, Cr2O3 et d’oxydes de type spinelle Ni-Cr-Fe. La région de métal située à l’interface avec la couche d’oxyde est fortement endommagée, notamment par la formation d’un réseau de pores interconnectés permettant la diffusion rapide des espèces chlorées dans le cadre du mécanisme d’oxydation active se produisant dans ces conditions. En comparaison, à 650°C, la dégradation du matériau en présence du dépôt solide de NaCl est nettement ralentie, les couches de produits de corrosion sont moins épaisses et le substrat métallique très peu endommagé. Les différences de comportements entre les deux températures peuvent être comprises à travers des différences microstructurales et de volatilité de chlorures métalliques
Compositionally graded materials offer numerous advantages, including the ability to locally adjust the material composition to adapt it to service conditions while minimizing the risks of incompatibilities between materials. This thesis work focused on the development of a compositionally graded material system using the Laser Metal Deposition-powder process, starting from a low-alloy steel substrate to alloy 625. As this multi-material system is expected to exhibit good high-temperature corrosion resistance, its behavior in an air atmosphere at 800°C and 650°C, with and without a NaCl solid deposit, was studied.Characterization of the as-built compositionally gradient system revealed various microstructures and phases depending on the regions of the gradient. Metallurgical evolutions were highlighted during aging at 800°C, particularly in alloy 625 with the precipitation of the δ phase.The oxidation resistance of the system was studied in an air atmosphere at 800°C for up to 2 500 h. Parabolic kinetics related to the formation of a protective Cr2O3 layer were highlighted. The presence of a NaCl deposit catastrophically accelerated the degradation of alloy 625. In this case, the corrosion scale was thick, highly cracked or spalled and mainly composed of NiO, Cr2O3, and (Ni,Cr,Fe)3O4. The metal region at the interface with the oxide layer was severely damaged, especially by the formation of an interconnected voids network allowing the rapid diffusion of chlorinated species in the active oxidation mechanism occurring under these conditions. In comparison, at 650°C, material degradation with a NaCl deposit was significantly slowed, with a thinner corrosion scale, and a less damaged substrate. Differences in behavior between the two temperatures can be understood through differences in microstructural characteristics and the volatility of metal chlorides."

ABSTRACT The Viburnum Trend, a Mississippi Valley–type Pb-Zn-Cu-(Ag) ore district, USA, is primarily hosted within the Cambrian Bonneterre Formation. Primary ore mineralization consists of galena, sphalerite, and chalcopyrite. Primary gangue minerals include dolomite and calcite, with lesser amounts of quartz, pyrite, and marcasite also present. The paragenetic sequence is complex, involving multiple generations of sulfide ore minerals. Early minerals are disseminated throughout the host rock. The main ore-stage deposition mostly occurs as colloform ore, while late-stage deposition primarily includes vug-filling ore. The geochemistry of deposits within the trend requires a complex fluid history, consistent with the mixing of multiple chemically distinct fluids to initiate ore precipitation. Salinities of included fluids range from less than 5 to ~30 wt% equivalent NaCl. Fluid chemistries align with the presence of a northward-migrating fluid, likely propelled through the Arkoma Basin due to hydrologic head provided by the Ouachita orogen, and a southward- or westward-migrating fluid, likely escaping the Illinois Basin due to overpressuring during sediment compaction and associated subsidence. Ore deposition probably commenced through fluid mixing. Lead and sulfur isotope chemistries of included fluids and associated solid phases suggest that multiple sources contributed lead and sulfur present in ore-stage mineralization. Additionally, ore fluids seem to have interacted with igneous basement rocks, likely acquiring lead, copper, and sulfur during migration through faults and fractures. The Viburnum Trend is relatively well understood; however, significant questions persist regarding fluid flow–driving mechanisms and pathways, sulfur sources, sulfate reduction reactions, metal sources, interaction with basement rocks, and the role of organic material in the host rock.

Pollution is the adverse alteration of the physical, chemical, and/or biological characteristics of air, water, or soil brought on by the presence of an excessive amount of different contaminants known as pollutants. Pollutants are dangerous substances that can be either foreign chemicals, energies, or contaminants that occur naturally. Both substances and energies can be considered forms of pollution. Air pollutants are separated into primary and secondary categories depending on whether they are directly released from the source or are formed by the reaction of primary pollutants with other species. They can be generated as the result of various human activities or natural events, and the same is true for water pollution. Many of the anthropogenic activities like transportation, and the various vehicles - autos and buses- by-products released are carbon monoxide, oxides of nitrogen, and particulate matter that can pollute the air. Natural processes can also release their specific contaminant like volcanic eruption (SO2, CO, Fine PM), biogenic emissions (VOCs, terpenes, isoprenes, pollen) and cause air as well as other types of pollution. The second classification is based on the physical characteristics of the pollutant; the first in this are gases such as carbon monoxide, ozone, nitrogen oxides, and sulphur; the second includes particulate matter (PM), such as carbon black, and heavier hydrocarbons which are in form of aerosols, suspensions of liquid and solid particles in the atmosphere. Numerous antigens with a proteinaceous nature that are mostly airborne and known as aeroallergens are also pollutants that might result in allergic responses. They can be produced by household dust, pets, medications, food, pollens, fungi, and mite products. Additionally, these goods contain the antigens absorbed and transported by organic or inorganic dust particles. The concentration of pollutants in the natural environment is increasing at alarming rates, which is not good for both human and animal health. Both internal and external bodily parts may be impacted by them. This could eventually lead to the slow deterioration of these organs. Proper maintenance on a regular basis must be carried out in order to maintain the proper health of the body's external parts. The pollutants may get deposit filth on the skin, and some chemicals may even reach the deeper layers of the skin. Human skin's protective barriers may be reduced as a result of their presence. This can also result in issues of the skin like pigmentation, tone patches, dullness, and wrinkle development, leading to premature aging of the skin. The water contains some extra pollutants also namely pathogens, poisonous minerals, and dead and decomposing things present in greater amounts and can therefore have a more impact if they come into touch with skin. The penetration of air pollutants through the epidermis and pores is more prominent due to the majority of these components being in liquid form. Various cosmetic preparations can be used for this purpose. According to EU Regulation 1223/2009, “Cosmetic product means any substance or mixture intended to be placed in contact with the external parts of the human body (epidermis, hair system, nail, lips, and external genital organs) or with the teeth and the mucous membranes of the oral cavity with the view exclusively or mainly to cleaning them, perfuming them, changing their appearance, protecting them, keeping them in good condition or correcting body odours”. Cosmetic products are classified as leave-on or wash-off products. The products containing natural ingredients available now are superior to fully synthetic products. Thus, switching from chemicals to natural products that contain some inert components can be can help effectively achieve the goal. Several patents have also been granted for cosmetic products of natural origin. The main strategy should be to deep clean, provide complete protection, protect against attacks and restore proper function. A better understanding of pollutants and their mechanisms of action on the body has led to the development of better products

Hydrocarbons transported in transmission pipelines contain solid particles with micro-attached water. Subjected to flow conditions, these particles may have sufficient density to reach the pipe floor and enable bacteria growth and local Under-Deposit Corrosion (UDC), with this form of corrosion being one of the principal threats to the integrity of oil and gas transmission pipelines. NACE International has published a variety of UDC related standard practices to manage corrosion in the oil industry such NACE 61114, but few of them are representative of, or applicable to, low water cut hydrocarbon transmission pipelines. Further, there are presently no industry recognized key performance indicators (KPIs) suitable for managing UDC in low water cut hydrocarbon transmission pipelines. Enbridge (the “Company”) operates North America’s largest interconnected liquid hydrocarbon transmission pipeline network. For the purposes of this paper, when the word ‘transmission’ is used to modify ‘crude oil’, ‘hydrocarbons’, or ‘pipelines’, it implies medium to long distance transport (100’s to 1000’s of km) as well as clean, “refinery-ready” crude oil (oil containing less than 0.5% sediment and water). This quality of oil renders it generally non-corrosive at pipeline operating conditions. However, if water wet particulates accumulate on the pipe floor, it can lead to UDC. The Company collects sludge samples produced during pigging operations on a regular basis to establish the composition of these materials and quantify bacterial population/activity. These solids represent an amalgamation of material removed from the pipe floor, and thus can be used as an indicator of the UDC threat in the pipeline. This paper builds upon previous work of the Company [1] by considering a larger data set in order to generate a more meaningful assessment of bacteria population/activity and provide better correlations with crystalline compounds, water content and elements found in the sludge. This paper presents these data and associated statistical analysis, and proposes KPIs for evaluating the UDC threat based on numerous variables, including in-line inspection Magnetic Flux Leak (MFL) data (through signal to signal corrosion growth rates), sludge analysis, flow conditions and pipeline operation; this paper also suggests mitigation activities and intervals relative to these KPIs. Personnel involved in pipeline integrity management (e.g. field operations, technical and management staff) may find the concepts, strategies and correlations presented herein to be useful in developing their own UDC management programs.

— Flashover on the insulation, as a result of the pollutants deposition present in the air on the surface of the insulator, has significant consequences on the reliability and safety of the power system due to its direct impact on the reduction of the availability of high-voltage electrical equipment that contains insulators for external installation. Although the occurrence of fault as a consequence of pollution is a known phenomenon since the beginning of electricity transmission, it has gained importance in recent decades with the increased scope of industrial development and more intensive cultivation and treatment of agricultural land. In this paper, the influence of the most common salt mixture present in agricultural fertilizers (NaCl, K2SO4, NaHCO3, CaSO4, KHCO3, MgSO4, NH42Fe(SO4)2x6H2O, iron ammonium sulphate, dust and urea) on the withstand voltages and the risk of flashover on cap and pin type insulator has been considered. The presented results show that soluble salts as well as solid insoluble deposits significantly affect the withstand voltages reduction of insulators, especially in the case of thicker solid insoluble deposits. Based on these results and the classification of the degree of pollution in accordance with the IEC 60815-1 standard, conclusions were drawn and guidelines were given for the dimensioning of insulation in the phase of developing projects for high-voltage transmission lines with the aim of achieving reliable behaviour of this electrical equipment in operational conditions with increased agricultural pollution.