Dalibor Jovanovic

Investigation of soil properties influence on the heavy metals sorption by plants and possibilities for prediction of their bioaccumulation by response surface methodology

The aim of this study was to determine soil properties influence on the heavy metals sorption by vegetables which are used in the diet and possibilities for prediction of their bioaccumulation by response surface methodology (RSM). Lettuce was used as biosorbent, and cadmium (Cd) and lead (Pb) were used as contaminants. Lettuce is grown on compost (previously contaminated with different concentrations of Cd and Pb) which pH was adjusted with different amounts of NPK fertilizers. The content of heavy metals was determined by ICP-MS. Results showed that Cd content in lettuce was below the toxic values, but Pb concentration was above allowable, which indicates that limit value for Pb is not set in accordance with the food safety regulations. It was found that the heavy metals accumulation in plants depends not only on its content in the soil, but also on the plant affinity to the specific metal, and the individual or the interactive effects of different soil properties. Through the transfer factor it was found that lettuce has a much higher affinity to Cd in relation to Pb. RSM has proved to be very good for the examination of a large number of variables with a small number of experiments.

The influence of the passive evaporative cooling vest on a chemical industry workers and physiological strain level in hot conditions

The present study was conducted in order to evaluate efficiency of a personal body cooling system based on passive evaporative technologies and its effects on test subjects psycho-physiological suitability during exertional heat stress in hot environment. Performed results are based on conducted tests in climatic chamber in the Military Medical Academy Institute of Hygiene in Belgrade. Ten male test subjects were subjected to exertional heat stress test consisted of walking on motorized treadmill at a speed of 5 km/h in hot environment. Tests were performed with and without cooling system. As a physiological strain indicator the following parameters have been determined: mean skin temperature, tympanic temperature, heart rate and sweat rate. Results confirmed that cooling vest worn over the clothes was able to attenuate the physiological strain levels during exercise, when compared to identical exposure without the cooling system.

The aircraft structural elements corrosion study using strain gauge method and pulse video thermography

Simultaneous influence of corrosion, static and dynamic loads on the elements of aircraft structures influence to a large extent their mechanical properties and the foreseen length of their service. The paper presents the influence of corrosion on physical and mechanical properties of the test bars made from materials for a wide range of applications which are used in aircraft structural elements manufacturing. Study comprises laboratory testing of bars for the simultaneous influence of corrosive environment, static and dynamic load. The problems are pinpointed regarding the use of strain gauges for continuous monitoring of the condition in real time. In addition, this paper deals with a modern non-destructive testing and evaluation system (NDT&E), whose operation is based on thermal image processing. Thermographic method has been used to detect a hidden corrosion in the aircraft structure in real life. The study results have shown the possibility of NDT application in simple and quick detection of areas affected by corrosion that are visually invisible