Abstract. Presented in this paper are some results from an investigation on the restriction of aviation noise contamination on the Sofia airport sanitary protected area, as well as some suggestions for solving this problem.

Космическите отпадъци – сериозен проблем за космическите полети

П. Ангелов, П. Христов, Н. Гушева

Space debris - a growing problem for space missions

P. Angelov, P. Hristov, M. Gousheva

Abstract. Space debris is recognized as a present and growing hazard for both humans and machines in space. In the paper, the changing status of space debris population from the beginning of space era is presented. The space debris risks to human and robotic missions are described. Some orbital debris mitigation recommendations and practices are described too.

Пестициди и микроорганизми

Д. Денчев, Е. Вачева, Ю. Бебова

Pesticides and microorganisms

D. Denchev, E. Vacheva, J. Bebova

Abstract. The main topic of this publication is the investigation of pesticides on soil microflora. The question of kinds of pesticides, their toxicity and spread is considered. The reactions of microorganisms to the presence of pesticides in both natural and laboratory conditions are discussed. Some of the most important methods for studying the influence of pesticides on microorganisms are examined.

М. Солакова, М. Богданова, Ст. Крайчев

A possibility of neutralizing and purifying acid drain waters with heavy salt composition from mining

M. Solakova, M. Bogdanova, St. Kraichev

Аbstract: This paper presents a possible technical solution for the construction of facilities for drain acid waters. The solution is based on personal research work as well as on the data submitted by authors working in this field [1,2]. This solution envisages the drained acid water from the Asarel-Medet East pit dump to be neutralized and treated to the levels admissible for discharging into II category water recipient rivers. Thus the sludge could be used in the construction of some facade elements such as pavement tiles, curbs, etc.

Изследване на инхибиращото действие на медни йони върху имобилизирана уреаза

К. Габровска, Ц. Годжевъргова

A study of copper ions inhibition effect on immobilized urease

K. Gabrovska, T. Godjevargova

Abstract: Poly (acrylonitrile-methylmethacrylate-sodium vinylsulphonate) membranes, molecular weight cut – off 10000, were subjected to chemical modification with 10% hydroxylamine-o-sulfuric acid. The amount of new groups incorporated in the membrane was measured. Urease was covalently immobilized on the modified membranes. The conditions for optimal immobilization and retention of stability of the immobilized enzyme were determined. It was found that the optimal conditions for immobilization were: time - 24 h; temperature - 4⁰C and urease concentration – 0,1%. The immobilized urease lost 30% of its enzyme activity for 30 days, while the free urease lost 62%. The inhibition influence of Cu²⁺on the activity of urease, both in the native form and immobilized covalently on a modified PAN membrane, was studied. K_i and IC₅₀ were also determined. This property of the enzyme offers a possibility of its analytical application.

Изследване и оптимизация на анаеробното разграждане на органични отпадъци

Д.Гълъбова, И.Симеонов, Д.Далев, Д.Каракашев

Research and optimization of the anaerobic digestion of organic wastes

D. Galabova, I. Simeonov, D. Dalev, D. Karakashev

Abstract. Experiments with different single and complex substrates of organic wastes were carried out in laboratory anaerobic continuous stirred tank bioreactors. The aim of the study is to obtain new knowledge about the process of anaerobic digestion of cattle manure, of activated sludge from a municipal wastewater treatment station, of a mixture of activated sludge and cattle manure and of a mixture of milk whey and cattle manure. During some experiments step-like and impulse-like stimulations with glucose and acetate of the processes with cattle dung and activated sludge were carried out. The effect of two surfactants, Triton X 100 and biosurfactant on the metabolism of pure bacterial cultures involved in anaerobic digestion was also studied.

Възможности за повишаване ефективността на радиационния мутагенез

А. Механджиев, С. Чанкова

Opportunities of increasing the efficiency of radiation mutagenesis

A. Mehandjiev, S. Chankova

Abstract. The experimental work was carried out with P. sativum and Cl. vulgaris. More mutagenic efficiency of the combined treatment of g-rays and EMS was established. Presynthetic phase G₁ is the most suitable phase for the induction of mutations. The chemical modificators connected with cell energy enhanced to a great extent the mutagenic efficiency of g-rays. These investigations contribute to the enrichment of peas and soybean gene pool.

Методологическо и информационно осигуряване на някои аспекти в птицевъдството

Кр. Лякова, Ю. Павлов

Methodological and information maintenance of some aspects in poultry farming

Kr. Lyakova, J. Pavlov

Abstract: The main purpose of the paper is the presentation of an integral mathematically grounded methodology for estimations and prognoses of hens and broilers development. The different parts of the paper do not demonstrate the proposed methodology in its intedriti as a completed investigation, but rather the practical efficiency of the methods and their limits of accuracy in their connections in the methodology. Essential mathematical parts of the methodology are regression analysis and multiattribute linear extrapolation (MLE). The presented methodology is a possible way to overcome the uncertainty of the empirical data (noise, insufficient data, etc.). The methodology is applicable even when the least squares method is not.

Апаратура за хидрометрични наблюдения

Е. Алтимирски, П. Константинов, Р. Петров

Equipment for hydrometrical observations

E. Altimirski, P. Konstantinov, R. Petrov

Abstract: The paper analyses automatic hydrometrical station typical parameters and describes a given station of this type, developed at the Technical University of Sofia. This station aims at exchanging the mechanical level measuring stations, used till nowadays in Bulgarian national hydrometrical system. The above mentioned station includes an electronical manometer for level measurements, a microcontroller and a radiocommunications system. Data is being transmitted upon request from the terminal station, and/or as a result of the automatic station self – initiative, periodically or upon reaching given level values. Details about the technical parameters of the station are given also.

Лаборатория "Биопроцесни системи"

Л. Николов

Laboratory “Bioprocess systems”

L. Nikolov

Abstract. Laboratory of Bioprocess Systems as scientific and education venue in the Biological Faculty of Sofia University is presented. The main reasons of its organisation in Biological Faculty are analysed. The name "Bioprocess systems" as a new notion introduced to the scientific literature to reflect the system approach implementation as the dominating methodology for bioreactor developments is justified. The ecological engineering as the main trend of the research and teaching for 15 years Laboratory activity is outlined. Achievements of the Laboratory are discussed on the basis of its scientific production referenced in the literature to this paper.

СЪДЪРЖАНИЕ

И. Симеонов 3

I. Човек и биосфера

М. Солакова, М. Богданова, Ст. Крайчев 26

А. Механджиев, С. Чанкова 44

Кр. Лякова, Ю. Павлов 52

Д. Денчев, Е. Вачева, Ю. Бебова

Pesticides and microorganisms