Bulgarian Academy of Sciences

About: Bulgarian Academy of Sciences is a government organization based out in Sofia, Bulgaria. It is known for research contribution in the topics: Coupling constant & Catalysis. The organization has 17989 authors who have published 36276 publications receiving 642820 citations. The organization is also known as: Bulgarian Academy of Sciences，簡稱：BAS & Balgarska Akademiya na Naukite.

From Observation to Information and Users: The Copernicus Marine Service Perspective

Abstract: The Copernicus Marine Environment Monitoring Service (CMEMS) provides regular and systematic reference information on the physical and biogeochemical ocean and sea-ice state for the global ocean and the European regional seas. CMEMS serves a wide range of users (more than 15,000 users are now registered to the service) and applications. Observations are a fundamental pillar of the CMEMS value-added chain that goes from observation to information and users. Observations are used by CMEMS Thematic Assembly Centres (TACs) to derive high-level data products and by CMEMS Monitoring and Forecasting Centres (MFCs) to validate and constrain their global and regional ocean analysis and forecasting systems. This paper presents an overview of CMEMS, its evolution, and how the value of in situ and satellite observations is increased through the generation of high-level products ready to be used by downstream applications and services. The complementary nature of satellite and in situ observations is highlighted. Long-term perspectives for the development of CMEMS are described and implications for the evolution of the in situ and satellite observing systems are outlined. Results from Observing System Evaluations (OSEs) and Observing System Simulation Experiments (OSSEs) illustrate the high dependencies of CMEMS systems on observations. Finally future CMEMS requirements for both satellite and in situ observations are detailed.

Photodegradation of thiacloprid using Fe/TiO2 as a heterogeneous photo-Fenton catalyst

Abstract: Three Fe/TiO2 photocatalysts with different content of Fe (1.9, 7.2 and 13.9%, w/w) were synthesized by a simple deposition–precipitation method and characterized by XRD, SEM, N2 physisorption at 77 K and Mossbauer spectroscopy. The characterization showed the presence of nano-sized Fe2O3 particles (less than 4 nm) on the TiO2 support. The photocatalytic efficiency of the catalysts was examined on the example of thiacloprid (TCL) degradation under UV light irradiation in aqueous suspension in the presence/absence of H2O2. Since the efficiency of TCL degradation in the presence of H2O2 (heterogeneous photo-Fenton process) was more than two times higher, all other investigations were conducted in the presence of H2O2. The photocatalyst with 7.2%, w/w Fe (denoted as 7.2Fe/TiO2) appeared to be most efficient. The photocatalytic degradation studied under different operating conditions indicated that 0.5 g L−1 of 7.2Fe/TiO2 was an optimal catalyst loading, and the optimal pH was 2.8. In the investigated range of initial concentrations of TCL (0.06–0.32 mM) the photocatalytic degradation in the first stage of the reaction followed approximately a pseudo-first order kinetics. The suspended Fe/TiO2 spontaneously precipitated once the stirring of the reaction mixture was terminated (>90% after 15 min). The results clearly demonstrated that 7.2Fe/TiO2 was stable and resistant to photocorrosion during the photocatalytic degradation of TCL. The higher efficiency of 7.2Fe/TiO2 compared to Degussa P25 under the optimal experimental conditions of TCL photodegradation, spontaneous precipitation of the suspension, possibility of reusing the catalyst, as well as an insignificant increase in the iron concentration in water solution, all this indicates the possibility of the practical application of this photocatalyst for water treatment.

The special functions of fractional calculus as generalized fractional calculus operators of some basic functions

Abstract: We propose a unified approach to the so-called Special Functions of Fractional Calculus (SFs of FC), recently enjoying increasing interest from both theoretical mathematicians and applied scientists. This is due to their role as solutions of fractional order differential and integral equations, as the better mathematical models of phenomena of various physical, engineering, automatization, chemical, biological, Earth science, economics etc. nature. Our approach is based on the use of Generalized Fractional Calculus (GFC) operators. Namely, we show that all the Wright generalized hypergeometric functions (W.ghf-s) Ψ q p ( z ) can be represented as generalized fractional integrals, derivatives or differ-integrals of three basic simpler functions as cos q − p ( z ) , exp ( z ) and Ψ 0 1 ( z ) (reducible in particular to the elementary function z α ( 1 − z ) β , the Beta-distribution), depending on whether p q , p = q or p = q + 1 and on the values of their indices and parameters. In this way, the SFs of FC can be separated into three classes with similar behaviour, and also new integral and differential formulas can be derived, useful for computational procedures.

Complete oxidation of benzene on manganese dioxide by ozone

Abstract: The kinetics of complete catalytic oxidation of benzene by ozone on MnO2 in gradientless conditions has been investigated. It was established that the decomposition of ozone and the oxidation of benzene on MnO2 proceed within the same temperature range (10–80 °C ), and the apparent activation energies are 32 kJ/mol and 30 kJ/mol, respectively. The complete oxidation of benzene by molecular oxygen takes place at temperatures above 160°C with an apparent activation energy of 88 kJ/mol. It has been assumed that the rate-determining step of complete oxidation by ozone is the ozone decomposition.