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The results of satellite monitoring with SAR of oil pollution in the Barents Sea conducted in 2017–2019 are presented. The statistics and summary maps of oil pollution of different type, detected and mapped are analyzed.

This paper presents the results of multiyear satellite monitoring of oil pollution in the Barents Sea conducted in 2015-2020. Monitoring was based on synthetic aperture radar (SAR) images from the European Space Agency's Sentinel-1A and Sentinel-1B satellites. During monitoring, more than 26,000 SAR images were collected and analyzed for oil pollution in the form of oil spills. A geographic information system (GIS) and a conventional interactive technique were used to efficiently analyze a substantial number of SAR images covering the Barents Sea. Our approach employed online geoportal based on GIS technology with a large volume of additional information (oceanographic, physical-geographical, and industrial) about the marine basin, including those for offshore oil and gas infrastructure. As a result, multiyear oil spill distribution map was generated and analyzed, and the most oil-polluted regions of the sea and natural seeps were identified. The analysis focused on the general characteristics of the spatial and temporal distribution and the main sources of oil pollution of the Barents Sea. Sources of oil spills with areas ranging from 0.5 to 90 km

The possibilities of high and medium resolution optical satellite imagery to monitor and control of sewer discharges in the coastal zone of the Black Sea nearby the towns of Sevastopol and Balaklava are examined. Based on the results of the satellite image analysis, the locations of waste emissions in the waters adjacent to the Golubaya Bay (Sevastopol region) and Balaklava were identified, the areas of water pollution and their occurrence reasons in a narrow coastal zone were determined. It is shown that untreated sewer discharges can be unambiguously identified on images acquired from space, and in case of volley emissions, satellite imagery can quickly determine the real situation in the sea, control the dynamics of wastewater in the coastal zone and finally assess the risks of seashore pollution.

The results of the satellite monitoring of oil spills in the Barents Sea are analysed and discussed. For the first time, in 2015–2016, synthetic aperture radar (SAR) images occurred regularly using...

This article presents the results of routine satellite oil spill monitoring in the Eastern Black Sea 2011–2013 and the Northern & Middle Caspian Sea 2009–2013 by analysing synthetic aperture radar SAR images acquired by space-borne SARs on board the European Environmental Satellite, Canadian SAR-equipped Radarsat-1, and Radarsat-2. The focus of operational monitoring is to provide information that assists in adequate responses, as well as further investigates the problem of recent oil pollution in these seas. A number of state-of-the-art technologies developed by Research and Development Centre SCANEX have been used to address this problem. For example, GeoMixer allows the integration and combination of all information needed for analysis by integrating all detected and verified spills and combining annual oil spill distribution maps and comparing them. Distributions of oil spills in the Black Sea and in the Caspian Sea are quite different, i.e. in their spatial patterns. In the Black Sea, the most important source of oil pollution is tank washing in the open sea producing spills of 20–100 km2 or more and illegal discharges. In the Caspian Sea, most of the detected oil spills in the northern and middle sections are from small ship-made discharges ≤10 km2 related to cargo traffic and fisheries. Despite the oil exploration and production LUKOIL and others in the Northern Caspian, no oil spills related to oil production have been detected. An ill-estimated source is natural oil seeping, mainly in the southern part of the Caspian. It is therefore concluded that the distribution of oil spills in a particular sea may depend strongly on a number of causes, including ship and tanker traffic.

During routine oil spill monitoring in the eastern Black Sea in 2011 and 2012 by RDC ScanEx, unprecedentedly large patches of oil of shipping origin were detected on synthetic aperture radar (SAR) images. The oil spills were detected mostly in the Russian sector of the sea or on its borders. The presence of large oil spills was confirmed using Terra and Aqua optical images. Using automated identification systems data, the vessel candidates were identified, and two of them were inspected. This paper presents for the first time the results of monitoring that show that the central part of the Black Sea is used for tank-washing operations and illegal dumping of oily products. The legality of producing these spills in the framework of the International Convention for the Prevention of Pollution from Ships (MARPOL) is also discussed. These and other similar events registered during the monitoring require the attention of environmental and nature conservation organizations. Summary maps of large oil spills detec...

The microwave dielectric properties of CaTi 1-x (Al 1/2 Ta 1/2 ) x O 3 solid solutions (0.3 ≤ x ≤ 0.5) have been investigated. The ceramic samples had perovskite structures similar to CaTiO 3 . The partial substitution of Ti 4+ by a coupled Al 3+ /Ta 5+ permitted improvement of the quality factor Q. The dielectric constant (e r ) and temperature coefficient of resonant frequency (τ f ) decrease rapidly with an increase of x. A new high-quality microwave dielectric material was found at x = 0.46 with e r = 46.5, Q.f = 27300 GHz, and τ f = 0 ppm/°C. The relationship between microstructures and dielectric properties is presented.

The piezoelectric properties of Pb[Zr0.45Ti0.5-xLux(Mn1/3-Sb2/3)0.05]O3 ceramics, with 0 lessthan equal to x lessthan equal to 0.03, have been investigated. The partial substitution of Ti4+ with Lu3+ permitted improvement of the electromechanical coupling factor (kp), the dielectric constant (epsilonT33), and the piezoelectric constant (d33), while the dielectric loss (tan delta) increased and the mechanical quality factor (Qm) decreased with an increase of x. A pertinent piezoelectric material for actuator applications was Pb[Zr0.45Ti0.48Lu0.02(Mn1/3Sb2/3)0.05]O3, and the piezoelectric properties were kp = (58.5 ± 0.5)%, epsilonT33 = 32 ± 25, d33 = (373 ± 6) 10-12 C/N, Qm = 714 ± 22, and tan delta = (0.98 ± 0.03)%.

The dielectric properties of (Pb 1-x Ca X )((Fe 1/2 Nb 1/2 ) 1-y Sn Y }O 3 solid solutions, where 0.4 < x ≤ 0.6, y = 0.05, 0.1, have been investigated at microwave frequencies. The replacement of Fe 3+ /Nb S+ by Sn 4+ at the B-site of the perovskite structure considerably improves the loss quality factor Q and does not remarkably affect the dielectric constant e r and the temperature coefficient of resonant frequency T f . The T f value of nearly 0 ppm/°C can be realized for x = 0.55. New high-quality dielectric ceramics having e r of 85.3-89.9, Qf values of 7510-8600 GHz, and T f of 0-9 ppm/°C were obtained at 1150°C for 3 h sintering in air. The influence of the sintering atmosphere on dielectric properties was also investigated.

Dielectric properties of the system (1 − x)(La1/2Na1/2)TiO3–xCa(Fe1/2Nb1/2)O3, where 0.4 #x# 0.6, have been investigated at microwave frequencies. The temperature coefficient of resonant frequency (τf), nearly 0 ppm/°C, was realized at x= 0.58. These ceramics had perovskite structure and showed relatively low dielectric losses. A new dielectric material applicable to microwave devices having Q·f of 12000–14000 GHz and a dielectric constant (er) of 59–60 has been obtained at 1300–1350°C for 5–15 h sintering.

The microwave dielectric properties of CaTi 1 -x (Al 1/2Nb1/2)xO3 solid solutions (0.3 ≤ x ≤ 0.7) have been investigated. The sintered samples had perovskite structures similar to CaTiO 3 . The substitution of Ti 4+ by Al 3+ /Nb 5+ improved the quality factor Q of the sintered specimens. A small addition of Li 3 NbO 4 (about 1 wt%) was found to be very effective for lowering sintering temperature of ceramics from 1450-1500° to 1300°C. The composition with x = 0.5 sintered at 1300°C for 5 h revealed excellent dielectric properties, namely, a dielectric constant (e r ) of 48, a Q x f value of 32 100 GHz, and a temperature coefficient of the resonant frequency (T f ) of -2 ppm/K. Li 3 NbO 4 as a sintering additive had no harmful influence on T f of ceramics.

Cu L α,s and O k α x-ray emission spectra and the measurements of the occupancy of Cu 3d orbitals in Bi 2 Sr 2 Ca 1−x Y x Cu 2 O 8+δ are presented. No appreciable change in the valency of Cu is found with increasing x. In contrast to La 2− y Sr y CuO 4 and YBa 2 Cu 3 O 6+y , when going from non-metal to metal, the high-energy shift of O K α band, caused by redistribution of the O 2p states of the apical oxygen atoms, is not observed. The valence states of Cu and O do not essentially redistribute due to Ca doping and the p-d energy separation does not change.

The microwave dielectric properties of (1 –x)(Al1/2Ta1/2)O2–x(Mg1/3Ta2/3)O2 (0 ≤x≤ 1.0) ceramics were investigated. (Al1/2Ta1/2)O2 and (Mg1/3Ta2/3)O2 had orthorhombic and tetragonal structure, respectively. As (Mg1/3Ta2/3)O2 concentration increased, (1 – x)(Al1/2Ta1/2)O2–x(Mg1/3Ta2/3)O2 transformed to tetragonal structure. Specimens having a tetragonal single phase could be obtained for x > 0.6. As (Mg1/3Ta2/3)O2 concentration increased, the grain size, dielectric constant (ɛr) and quality factor (Q) significantly increased, and the temperature coefficient of resonant frequency (τf) changed from a negative to a positive value. A τf of 0 ppm/°C was realized at x= 0.65 and the Qfo value and ɛr for this composition were 112 470 GHz and 26.1, respectively. The relationship between microstructures and dielectric properties was also investigated.

The microwave dielectric properties of CaTi 1-x (Al 1/2 Ta 1/2 ) x O 3 solid solutions (0.3 ≤ x ≤ 0.5) have been investigated. The ceramic samples had perovskite structures similar to CaTiO 3 . The partial substitution of Ti 4+ by a coupled Al 3+ /Ta 5+ permitted improvement of the quality factor Q. The dielectric constant (e r ) and temperature coefficient of resonant frequency (τ f ) decrease rapidly with an increase of x. A new high-quality microwave dielectric material was found at x = 0.46 with e r = 46.5, Q.f = 27300 GHz, and τ f = 0 ppm/°C. The relationship between microstructures and dielectric properties is presented.

Dielectric properties of the system (1 − x)(La1/2Na1/2)TiO3–xCa(Fe1/2Nb1/2)O3, where 0.4 #x# 0.6, have been investigated at microwave frequencies. The temperature coefficient of resonant frequency (τf), nearly 0 ppm/°C, was realized at x= 0.58. These ceramics had perovskite structure and showed relatively low dielectric losses. A new dielectric material applicable to microwave devices having Q·f of 12000–14000 GHz and a dielectric constant (er) of 59–60 has been obtained at 1300–1350°C for 5–15 h sintering.

The charge states of copper in Bi 2 Sr 2 Ca 1- x Y x Cu 2 O 8+° compounds with different yttrium concentrations have been investigat ed by means of X-ray photoelectron spectroscopy. It is shown that doping with yttrium leads to the diminution of hole numbers in the CuO 2 planes. At the same time, a decrease in the contribution of the Cu3d 9 (Cu 2+ ) configuration to the electron structure of this compound has been observed. The reduction of carrier density is accompanied by a variation of alkali earth spectrum shape.

The microwave dielectric properties of the CaTi1- x (Fe0.5Nb0.5) x O3 (0.4≤x≤0.7) solid solutions and the influence of 1 wt% ZnO as a sintering additive are investigated. With the increase of x, dielectric constant (ε r ) and product of quality factor and frequency (Q·f) decrease. The temperature coefficient of resonant frequency (τ f ) value of nearly 0 ppm/°C can be realized for x=0.54. The properties of this material are: ε r =59.9, Q·f=3870 GHz. ZnO forms a liquid phase on the grain boundaries and improves the sinterability and grain growth. The correlation between average grain size and Q-factor is observed for ZnO-doped ceramics.