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  • Author: Ana Mladenovič x
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Abstract

During carbon steel manufacturing, large amounts of electric arc furnace (EAF) slag are generated. EAF slag, if properly treated and processed into aggregate, is an alternative source of high-quality material, which can substitute the use of natural aggregates in most demanding applications in the construction sector, mostly for wearing asphalt courses. In this screening process of high-quality aggregates, a side material with grain size 0/32 mm is also produced, which can be used as an aggregate for unbound layers in road construction. In this study, the environmental impacts of slag aggregate (fraction 0/32 mm) were evaluated in mixed natural/slag aggregates. Different mixtures of natural/slag aggregates were prepared from aged (28 days) and fresh slag, and their environmental impacts were evaluated using leaching tests. It was shown that among the elements, chromium (Cr) was leached from some mixed aggregates in quantities that exceeded the criterion for inert waste. The data from the present investigation revealed that mixed aggregates, prepared from aged slag (fraction 0/32 mm) and natural stone in the ratio 10/90, are environmentally acceptable and can be safely used in unbound materials for road construction.

Abstract

In this study we performed a calculation of the tectonic stress tensor based on fault slip data and all available focal mechanisms in order to determine the principal stress axes and the recent tectonic regime of the westernmost unit of the Getic nappe system (Gornjak-Ravanica Zone, Eastern Serbia). The study is based on a combined dataset involving paleostress analyses, the inversion of focal mechanisms and remote sensing. The results show dominant strike-slip kinematics with the maximal compression axis oriented NNE-SSW. This is compatible with a combined northward motion and counterclockwise rotation of the Adria plate as the controlling factor. However, the local stress field is also shown to be of great importance and is superimposed on the far-field stress. We managed to distinguish three areas with distinct seismic activity. The northern part of the research area is characterized by transtensional tectonics, possibly under the influence of the extension in the areas situated more to the northeast. The central and seismically most active part is dominated by strike-slip tectonics whereas the southern area is slightly transpressional, possibly under the influence of the rigid Moesian Platform situated to the east of the research area. The dominant active fault systems are oriented N-S (to NE-SW) and NW-SE and they occur as structures of either regional or local significance. Regional structures are active in the northern and central part of the study area, while the active fault systems in the southern part are marked as locally important. This study suggests that seismicity of this area is controlled by the release of accumulated stress at local accommodation zones which are favourably oriented in respect to the active regional stress field.

Summary

Fear of needles can significantly limit professional and social functioning of a person, and is highly prevalent in general population (4%).

The aim of our study was to reveal risk factors that are associated with fear of needles among healthy university students of medicine and pharmacy.

The study was of a cross-sectional type. In total, 301 students of medicine or pharmacy (82% female and 18% male) attending from 1st to 5th year of study were surveyed at the Faculty of Medical Sciences, University of Kragujevac, Serbia. The students were surveyed using a questionnaires (scales) for assessing the fear of needless, a visual analog scale for self-assessment intensity of the fear of needless, and a general questionnaire with questions about socio-demographic characteristics of the participants. Using a score on the scales as out-come variables, multiple regressions were employed to reveal factors that may influence the fear of needles.

Average values of Blood/Injection Fear Scale, Injection Phobia Scale-Anxiety and Medical Avoidance Survey scores were 7.89 ± 9.48, 4.46 ± 5.18 and 89.95 ± 12.73, respectively. The following factors affected significantly the score of the scales: course of study, chronic disease in the family, fear of a dentist, smell of the room phobia, sound phobia, score on the Beck’s anxiety scale and fear of a situation when medical staff give an injection. The presence of chronic disease in the family was a protective factor, while the other six factors were contributing to the fear of needles.

Fear of needles is more prevalent among the students of pharmacy than among the students of medicine. It is less frequent among students with chronic disease in their family, while fear of dentist, smell of the room phobia, sound phobia, general anxiety and fear from the situation when medical staff give an injection are all factors that predispose students of medicine or pharmacy to develop fear of needles.