v.6 n.2 March

Parana Journal of Science and Education. v.6, n.2, March (2020).

Summary

Articles

A Potential Interpretation of Dark Matter.

Stefan Bernhard Rüster.

Parana J. Sci. Educ., v.6, n.2, (1-4), March 1, 2020.

DOI: doi.org/10.5281/zenodo.3872011

Abstract

In this article, the author makes use of simple Newtonian physics without the need for dark matter and Milgrom’s MOND theory in order to compute flat rotation curves of spiral galaxies. This approach is justified by the fact, that no dark matter particle has been detected, and also Milgrom’s MOND theory has its shortcomings. The gravitational potential energy density serves as the starting point for the calculation, which causes a new kind of gravitational force density, that has not been considered yet. Also a comparison with Milgrom’s MOND theory and its shortcomings is made. The author has an explanation why different values for Milgrom’s constant are required for agreement with different galaxies’ rotation curves. The new approach in the present article therefore yields a potential interpretation of dark matter in the sense, that the latter one is not necessary in order to explain the observed flat rotation curves of spiral galaxies.

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Oily effluents as source of water environment pollution.

Vasily Konstantinovich Novikov, Victoria Alexandrovna Kuzmichova and Sergey Vasiliyevich Novikov.

Parana J. Sci. Educ., v.6, n.2, (5-10), March 1, 2020.

DOI: doi.org/10.5281/zenodo.3872021

Abstract

There are described the adverse effects on the water environment (WE) caused by the oily effluents (OE). In particular, those are the energy & heat exchange imbalance between layers of water masses, the albedo reduction of seawater, the death of many marine animals and the pathological changes in organs and tissues of living organisms. The stages are listed of the processes having place in the oil pollutants trapped in WE that lead to the water physical properties deterioration such as changes in color, taste and smell. It is shown that among the main sources of the OE formation, there are the oil refineries, the gas stations, the filling stations and the pumping stations of the main oil pipelines. The main physical and chemical properties of OE that affect the OE action in WE are as follows: density, viscosity, solidification temperature, evaporation potential, and toxicity. The existing methods of OE purification from impurities containing oil and oil products are given here as follows: mechanical, chemical, physical-chemical and biological methods. The brief description of each method is given. The possible ways and methods are shown of untreated OE entering prevention into administrative, technical, and technological WE.

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Conformation stereoselective adapted for some steroids derivatives (Minireview).

Maria Lopez Ramos, Lauro Figueroa Valverde, Regina Cauich Carrillo and Rogaciano Torres Cutz.

Parana J. Sci. Educ., v.6, n.2, (11-22), March 1, 2020.

DOI: doi.org/10.5281/zenodo.3872025

Abstract

Stereochemistry is important to characterize the function of the compounds. For several decades, there has been interest in the study of the conformations in various steroid derivatives. The aim of this study was to review different stereochemistry conformation adopted by some steroid derivatives and their corresponding synthesis. The different conformations that steroids adopt mainly in both A and D rings depend on the substituted functional groups.

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