Thermo-degradative changes of rapeseed and sunflower oils during deep-frying French fries

The purpose of this study was to investigate changes in TPCs, acid value and peroxide value as well as fatty acids composition in edible oils during french fries production. Lower TPCs content was found in rapeseed oil (3.3%) and the threshold (24%) was achieved on the fourth day. The total time for the deterioration of deep-frying rapeseed oil was 23½ hours. On the contrary, in fresh sunflower oil at the first day was TPCs content 5.5% and the limit of 24% was reached on the third day. The total time for the deterioration of deep-frying sunflower oil was 17½ hours. The results indicated significant differences (<0.05) in TPCs content between rapeseed and sunflower oils during deep-frying process. At the beginning of deep-frying French fries in rapeseed oil, the acid number was 0.374 mg KOH.g-1 and 1.271 mg KOH.g-1 at the fourth day of deep-frying. The measured peroxide value was 4.3 mEq O2.kg-1 at the beginning and at the end of deep-frying 10.5 mEq O2.kg-1. The initial peroxide and acid values were higher in sunflower oil compared with rapeseed oil, respectively. It should be note, then the acid values and peroxide values, respectively, in the two fresh oils used in this study were below the limit of refined oil according to Slovak legislation (peroxide value - not more than 10 mEq O2.kg-1, acid value - not more than 0.6 mg KOH.g-1). However, detected values varied during deep-frying process. Monounsaturated fatty acids were predominantly observed in fresh rapeseed oil (61.22%) wherever in sunflower oil they were much lower (29.77%). A slight increase of MUFA was found in both oils. The initial content of saturated fatty acids in rapeseed oil was 6.94%, in fresh sunflower oil was observed slightly higher content of SFA (10.37%). The major groups of fatty acids in fresh sunflower oil were polyunsaturated fatty acids (PUFA) which have in principle a significant effect on oil deterioration. A slight decrease of PUFA was observed in both oils throughout the frying period. The content of PUFA was reduced by about 9.42% in rapeseed oil and by 10.8% in sunflower oil. The initial content was 28.14% and 58.91%, respectively

Modeling the profit from hydropower plant energy generation using dimensional analysis

Our work presents the original mathematical model, which can be determined on the basis of the actual profits from electricity production in pumped storage hydropower plants (PSHP). The derived relationship was obtained by the dimensional analysis of the relevant physical parameters describing the production of energy. The main purpose of this paper is to prove whether a dimensional analysis can be a useful tool to describe the economic aspect of the phenomenon, as proved by its worth when examining technical phenomena. The mathematical model has been derived for PSHP Ružín in Slovakia, but its validity, based on the similarity theory, can be extended to any pumping power plant that works with the influx of water into the upper storage reservoir, and/or without the feed, respectively. The article discusses the effects of various parameters on the operating profit for the turbine operations and the costs associated with the pumping operation.Web of Science251817

PERCEPTION OF APPLIED ECOLOGY BY SECONDARY SCHOOL STUDENTS

Applied ecology is a science that manages ecosystems including conservation, harvesting and animal and plant control. Environmental attitudes of secondary school students include their psychological tendency towards the environment. The study concentrates on secondary school students in the Košice Region, in Slovakia. Using Google Forms a questionnaire was delivered to 1,012 secondary school students from the mentioned region. From the participants 59.3% were female and 40.7% were male students. The most numerous age category was 17-year-old secondary school students. 76.6% were students at a secondary school with a general certificate of secondary education (GCSE), 22.1% at a grammar school and 1.3% at a secondary school without a GCSE. Based on the results of the questionnaire most students are interested in the quality of the environment on average and there is no student absolutely not interested in the quality of the environment regardless of the school type. No students, regardless of the school type, consider there is absolutely no impact of all anthropogenic activities on the quality of the environment. As to the assessment of environmental quality in the place of permanent residence and the knowledge of drinking water quality there is no conformity depending on the type of school. The most students save water on average regardless of the school type. There are no students definitely not saving energy in their households, but there is no compliance on saving energy in the households depending on the type of school. There are no students definitely not separating waste in their households and only a few students that rather not separate waste but most students definitely separate waste regardless of the school type

Environmental Impact Assessment and Hydraulic Modelling of Different Flood Protection Measures

The most appropriate method to protect settlements and economically important sites from flood hazard, is the implementation of flood protection measures in stream catchments and protected localities, which contribute to reduce the peak flow and distribution of the flood wave over a longer period of time. If such measures are not realistic or ineffective, it is necessary to focus on flood protection directly on the area of the protected side or its vicinity. Where the lag time between the flood threat detection and actual flood onset is short, one possible measure is to increase the capacity of the watercourse, very often in combination with other flood mitigation measures in the protected area. The engineering approach to flood protection is the subject of many scientific research studies. Permission for flood protection structures depends on their environmental impact assessment (EIA), according to Law no. 24/2002 Coll. on Environmental Impact Assessment in the Slovak Republic, annex no. 8 (list of activities subject to EIA). Based on the EIA, it is possible to select the best alternative of flood protection, i.e., the alternative with the lowest risk impact on the environment. This paper aims to analyse the flood protection measures along the Lukavica stream (central Slovakia), applying hydraulic models. The best alternative with the lowest impact on the environment, assessed using the risk analysis method, consists of detention reservoir construction. An effective combination of environmental impact assessment and hydraulic modelling contribute to the selection of an effective flood protection measure in the territory