EXPERIMENTS
Study of Compositions for Selective Water Isolation in Gas Wells
Al-Obaidi S.H. 1), Hofmann M.1), Smirnov V.I.1),
Khalaf F.H. 2), Alwan H.H. 2)
1)Mining Institute – Saint Petersburg (Russia)
2)Department of Petroleum Engineering, Knowledge University – Erbil (Iraq)
https://doi.org/10.53656/nat2021-6.04
Abstract. A hydrophobic composition containing water repellents and highly volatile solvents is shown in this study to isolate water from the bottomhole formation zone of gas wells and reduce as much as possible the saturation of pore spaces with water…
SCIENCE AND SOCIETY
Mutations and Variants of SARS-CoV-2, the Coronavirus Causing COVID-19
Lachezar Karagyozov
Sofia University
https://doi.org/10.53656/nat2021-6.05
Abstract. In 2020, the SARS-CoV-2 coronavirus caused a pandemic with severe consequences for many countries...
FROM THE RESEARCH LABORATORIES
Semiempirical Quantum Chemical and Ab Intio Study of Co(Ii), Ni(Ii),Cu(Ii) and Zn(Ii) Complexes With The Azo Dye Derived From 4-Amino Antipyrine and 2,4-Dihydroxy Acetopheone
Satya Narayan Chaulia
Rajendra (Auto) College (India)
https://doi.org/10.53656/nat2021-6.03
Abstract. Semi-empirical quantum chemical calculation was made to study the nucleophilicity of the ligand and to study the mode of bonding between the ligand and the metal ions.
On the Sound, Produced by a Coin, Rolling In A Balloon
Denitsa Vasileva
Sofia High School of Mathematics “Paisiy Hilendarski” – Sofia (Bulgaria)
https://doi.org/10.53656/nat2021-6.06
Abstract. Balloons may be a thing children love playing with, but they also have different interesting physical properties such as the sound that is produced when something is put inside a balloon…
CURRICULUM MATTERS
Difficult Topics In the Chemistry Curriculum - Bulgarian Students' View
Kalin Chakarov, Alexandria Gendjova
Sofia University
https://doi.org/10.53656/nat2021-6.02
Abstract. Chemistry is often considered a difficult subject, and the way students perceive learning affects their achievements...
NEW APPROACHES
Development of the Concept of Entropy: A Simpler Alternative to Carnot Cycle
Jamil Ahmad
University of Botswana (Botswana)
https://doi.org/10.53656/nat2021-6.01
Abstract. The relationship between entropy and reversible heat and temperature is developed using a simple cycle, in which an ideal gas is subjected to isothermal expansion and compression and heated and cooled between states…
