AbstractThis paper explores the accidents that occurred in the railway system of Serbian Railways from 2006 to 2012. The total number of the sample observed includes 3983 accidents, of which 2725 or 68.41% were caused by the human factor. One of the major contemporary problems – global climate change and the increase of average temperatures – has not yet been considered in the context of external factors for increasing the risk of accidents. The air pressure has become accepted as an external factor, in addition to the air temperature. It is assumed that temperature and air pressure have a significant impact on the risk of railway accidents occurrence (taking only accidents caused by a human factor into account). This assumption was made based on reduced cognitive abilities of railway staff as a result of extreme differences in temperature and air pressure. In this paper, the emphasis is put on Railway Crossings (RC) as sites where two forms of traffic intersect, since it is noticed that certain weather c...

Mechanical milling of commercial ZnO and SnO2 was used to produce a ZnO/SnO2 composite with a high density of surface defects; in particular, zinc interstitials (Zni) and oxygen vacancies (VO). To determine the impact of surface defects on photocatalytic activity, the relative concentration ratio of bulk defects to surface defects was modified by annealing at 400 and 700 °C. The possible application of the ZnO/SnO2 composite as a natural sunlight and UV-light driven photocatalyst was revealed via de-colorization of methylene blue. In both cases the ZnO/SnO2 composite exhibited enhanced photocatalytic activity as compared to the pristine ZnO. In order to investigate the origin of the enhancement, the pristine metal oxides and composites were characterized using a variety of techniques, including X-ray diffraction (XRD), Raman and Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FESEM), laser diffraction particle size analysis, Brunauer–Emmett–Teller, UV-Vis diffuse reflectance and photoluminescence spectroscopy. High-resolution transmission electron microscopy (HRTEM) and elemental mapping analyses were used to reveal the presence of SnO2 nanocrystallites on the surface of larger ZnO particles. The enhanced photocatalytic activity of the composite can be attributed to the synergetic effect of the surface defects and the ZnO/SnO2 heterojunction particles, which facilitated charge separation, thereby hindering the recombination of photogenerated carriers. This study draws attention to mechanical activation as an inexpensive and environmentally friendly technique for the large-scale production of the composite with an enhanced photocatalytic activity under illumination of either UV or sunlight.

Total phenolic (TPC), flavonoid (TFC) and tannin (TTC) contents, total SO2, total acids, pH, and reducing sugars were measured in twenty five Slovenian red wines from three key wine producing regions, Podravje, Posavje and Primorska. The results were chemometrically analysed and the wines were classified according to wine growing region and vine variety. Principal component analysis proved that TPC, TFC and TTC contents were primarily responsible for variation in the wines. Additionally, linear discriminant analysis (LDA) was performed and resulted in the satisfactory classification of samples by both vine variety and region.

Original scientific paper The paper presents analysis of the influence of cutting parameters on surface roughness during CO2 laser cutting process of tungsten alloy by using nitrogen as assist gas, based on control charts made by statistical process control (SPC) approach. Dependent variable is surface roughness, while independent variables are laser power and cutting speed. The control chart used within this paper is a variation of the moving means chart of experimental data samples, that calculates mean and range values using the three consecutive individual values. Applying the criteria often used in the SPC methods for the assessment of "out of control" situations, it may be inferred that increasing the cutting speed leads to worsening of control status for the process with lower laser power used.

Aim of this paper was to examine effectiveness and efficiency of examination of hearing status of persons with hearing impairment in form of applicable diagnostic software, in relation to classical approach. Sample was comprised of 90 respondents and was formed out of two subsamples. First subsample was comprised of 45 students with hearing impairment with a degree of impairment of over 80 dB, both genders, age from 6 to 15 years and without any other disabilities. Second subsample was comprised of 45 students (absolvents) from department of audiology. For data gathering, audiogram, applicable diagnostic software and scale for evaluation of attention and cooperation were used. Data was processed with descriptive analysis, McNemar and Wilcoxon tests. Results of the research confirmed that applicable diagnostic software provide more effective and more efficient diagnostic procedures for examining hearing status of persons with hearing impairment in relation to classical approach.

Introduction: Quantifying science and scientific contribution has become one of the main tasks in evaluating researchers and their impact. How do we value research and science in Bosnia and Herzegovina (BIH)? Scientific community has mostly agreed upon that one of the best ways to value researchers is through their h-index value. However, there are many databases and services from which h-index can be retrieved. Aim: To describe different databases and services such as Google Scholar, Web of Science, Scopus and Researchgate in evaluating the researcher. An additional aim of this paper is to present “the shape” of science at the University of Sarajevo and to examine what are the best predictors of h-index. Materials and methods: We analyzed the data from 100 Google Scholar Profiles of researchers from University of Sarajevo. Results: The study showed some benefits and shortcomings of mentioned databases and services. Most researchers in the sample were from natural sciences, in particular from the field of medicine. The mean value of h-index in relation to the researcher’s gender was not statistically significant. We conclude the article with some ideas on how to improve the visibility of researchers from BIH.

Isaacs Sedick, PhD (1940-2012) was born and grew up in the Bo-Kaap, Cape Town, Western Cape. From an early age, Isaacs was fascinated with science and was engaged in performing science experiments at home. At the age of 13, he was involved in distributing political pamphlets and attending meetings of the Teachers League of South Africa (TLSA) and the Non European Unity Movement (NEUM). After completing his education, Isaacs worked as teacher at Trafalgar High School in Cape Town. It was while teaching at the school that he met Achmad Cassiem. Isaacs with his knowledge of explosives tried to train some of his friends in the use of this. This attracted the attention of the security police who monitored their activities. Consequently,