Formaldehyde in screen printing indoor

The presence of formaldehyde in air samples has been detected in five screen printing facilities in Novi Sad, Serbia. Air samples were sampled continuously during 4 hours, and concentration levels of formaldehyde was determined by UV-VIS spectrometry at 580 nm. The range of formaldehyde concentrations was from 0.413 to 0.836 ppm. Comparison of the detected concentration levels with the permissible exposure limit of 0.75 ppm (the OSHA standard) indicated that the formaldehyde concentration in facility 5 was 1.11 times higher than prescribed value

Efficient Portfolio Selection and Its Applications to Decision Making

Abstract—Dynamic nature of investment return requires the application of the appropriate methodology, especially regarding enhanced volatility induced by frequent extreme events occurrence. The subject of the research is to analyze the possibility of efficient portfolio selection on the transitional financial market of the Republic of Serbia.  The main objective is to gather empirical evidence about the investment portfolio performance with special attention to the decision making process. The methodology in the research implies the usage of the appropriate portfolio optimization methods. The research results stress the significance of efficient portfolio selection in contemporary business conditions. It can be concluded that it is necessary to examine the volatility of the portfolio assets and thus enabling the efficient portfolio selection, which is especially challenging on transitional markets

Soil fertility as a condition of sustainable development

The purpose of this paper is to examine soil fertility parameters as indicators of sustainable management in order to preserve this resource for future generations. The parameters tested are the pH value of soil and humus content. The pH value of soil affects the presence and mobility of nutrients and their uptake by the plant. On the basis of potential acidity, the quantity and type of the needed fertilizer can be predicted. For the purpose of this research, 100 soil samples from the territory of western Serbia have been examined. Active acidity, i.e. the pH values of sample extracts in distilled water and potential acidity, i.e. the pH value in 1N potassium chloride solution were measured. As the remediation strategy for acid soils we have proposed the method of calcification with the determining of hydrolytic acidity. The presence of humus substances was determined using a method proposed by Kochman, based on the oxidation of organic matter from the soil with potassium permanganate solution (KMnO4). The released CO2 was determined indirectly by the retraction of the KMnO4 solution of oxalic acid and a method proposed by Tjurin, based on the oxidation of organic matter in the soil. Organic carbon was determined spectrophotometrically at 585 nm. Having obtained such insight into the measured values, we can confirm the dominant presence of strongly acidic and acidic soils. In terms of the amount of humus in soil, the obtained results were quite satisfactory, i.e. humus and very humus soils prevail on the observed territory

Contribution of Particles to Air Pollution in Green Parks

Parks can aid in the regulation of microclimates and the improvement of air quality. They can be utilized in real-world systems to choose the best model for explaining the source of pollutant emissions, indicating the requirement for pollution concentration monitoring. Monitoring concentration trends is critical to formulating a strategy to reduce CO2 emissions and the contribution of these gasses to the greenhouse effect, as well as to curbing the rising levels of PM in the air. The research background of this study was performed in the green parks of Novi Sad, Serbia. The results are represented in terms of the quantity of the pollutants, and the correlation of the examined phenomena through statistical analysis. Aeroqual monitors with laser sensors were used to take measurements of particle pollution (PM2.5/10). The constant was confirmed by inter-comparison laboratory measurements of air-quality quantitative control. The measurement findings revealed a minor variance in concentration values for PM2.5/10 from 26–30 μg/m3, which were within the allowed limits, indicating that the air was moderately clean. The linear link between particle concentrations and nitrogen dioxide in the sample was also validated using simple linear regression, as was the high influence of humidity on particle concentrations