Фактори на ризик за појава на кардиоваскуларни болести кај професионалните возачи

Aim of the paper was to determine the presence of risk factors for cardiovascular diseases (CVD) such as arterial hypertension, hyperlipidemia, hyperglycemia, overweight, smoking; and (ii) to analyze the link between the requirements of their job and the resources available to them. Materials and methods: A descriptive and analytical cross-sectional study was conducted involving 210 professional drivers who underwent a medical examination at the Institute for Occupational Health of the Republic of North Macedonia. The examination was done in order to assess their ability to drive a motor vehicle; they were also given a questionnaire to fill in so as to compare the requirements of the job and the resources available to them for doing their job. Results: One third of the respondents had increased levels of triglycerides, glycemia and cholesterol in their blood (33.3%, 28.1%, and 21.4%, respectively); almost half (44.2%) of them were active smokers. One third of the respondents (31.9%) were obese, with BMI >30 (kg/m2). The resources available to the professional drivers for doing their job exceed the requirements of the job and this situation has a protective effect on the occurrence of risk factors for CVD. Conclusion: The high prevalence of risk factors for CVD among professional drivers can lead to development of CVD and increased incidence thereof, which can negatively impact on their ability for safe driving. Hence the need for interventions to prevent these risk factors, including the need to invest in the resources available to professional drivers for doing their job.  Целта на трудот  беше да се детерминира присуството на факторите на ризик за појава на кардиоваскуларни болести (КВБ): артериска хипертензија, хиперлипидемија, хипергликемија, зголемена телесна тежина, пушачки статус, и да се анализира нивната поврзаност со барањата и ресурсите на работното место. Материјал и методи: дескриптивно-аналитичка студија на пресек, во која кај 210 професионални возачи беа анализирани дел од резултатите добиени при здравствениот преглед спроведен во Инситутот за медицина на трудот на РСМ при оценката на способноста за управување со моторно возило и резултатите за барањата и ресурсите на работното место добиени со соодветен прашалник. Резултати: Една третина од испитаниците имаа покачени вредности на триглицеридите во крвта (33,3%); гликемијата беше зголемен кај 28,1%,  холестеролот во крвта беше зголемен кај 21,4% и речиси половина (44,2%) од испитуваните професионални возачи беа активни пушачи. Третина (31,9%) од испитаниците беа обезни со BMI >30 (кг/м2). Ресурсите на работното место со кои располагаат испитуваните професионални возачи беа поголеми од барањата на работното место и овој модел има протективно дејство врз појавата на испитуваните фактори на ризик за КВБ. Заклучок: Високата преваленција на факторите на ризик за КВБ кај професионалните возачи може да придонесе за зачестена појава и развој на КВБ што, пак, може да влијае врз нивната способност за безбедно управување со моторно возило. Оттаму, произлегува потребата од интервенции за нивна превенција вклучително и инвестиција во ресурсите на работното место

Introducing Cooperative Learning in the English Language Classroom and Progress Tracking

The English language classroom has been experiencing a shift from the traditional approach towards a functional approach to teaching. The purpose is to abandon the classical lecture-and-note approach, passive role of students, an unproductive classroom and excessive teacher-reliance, thereby putting emphasis on interaction and collaboration in the English language classroom as well as on student autonomy in the learning process. The aim of this paper is to analyse efficient methods for teaching grammar and to explore which learning practices are deemed best by students. For the purposes of this research, a survey was conducted among 50 first-year students at the Faculty of Philology (whose progress in learning grammar was monitored in a period of two semesters). The results of the research indicate a need for applying an action-based approach in the English language classroom, whereas the authors suggest different cooperative learning strategies. Furthermore, the results demonstrate that teaching methods have an effect on the level of progress achieved by students, whereas the need for introducing progress tracking at faculty level is also discussed

VESSELS FOR STORAGING WINE IN ANCIENT ROME AND TODAY

Wine seems to be one of the oldest beverages known to man. In order for the wine to have the required quality and not posing a danger to human health, it is necessary, as part of the production process, to be stored in appropriate vessels before reaching the consumer. The authors of this article, using the historical method and the method of analysis and comparison, will merge two different periods: Rome and today. The unusual merging of two different periods of human civilization is aimed at proving the hypothesis of this article that wine storage vessels are not a creation of today world, and their development in modern times contributes to keeping the wine quality as a food agricultural product. Also, in the article, the authors will present the way of sale and inheritance of wine in Rome, because the storage of wine in the amphorae, during the sale or inheritance then, contributed to the preservation of its quality, sale and inheritance

A new methodology for prediction of high-cycle contact fatigue for spur gears

High-cycle contact fatigue is a localized phenomenon that occurs in highly stressed grains of the material on or under the contact region. The contact zones of tooth flanks for meshed gears are subjected to contact fatigue damages that causes pitting and leads to gears failure. The objective of this paper is to give a new viewpoint in contact fatigue prediction in the case of high-cycle fatigue. The main aim of the presented research is to make the methodology for direct calculation of fatigue crack initiation in contact zones. This methodology is developed for spur gears and used up-to-date methods and multidisciplinary approach. Two methods are built in the new methodology: the Theory of Critical Distances (TCD) and the Finite Element Method (FEM). In this paper the comparative analysis of standard and new methodology for prediction of fatigue crack initiation on tooth flanks is presented. The advantages of methods and procedures used in the new methodology are presented through a case study of particular gear pair. The Finite Element Analysis on 3D gear contact model is used for stress and strain calculation and prediction of the maximum stress location in contact zones along the gear face width. The stress gradient curves from the contact zone are made for a pinion tooth in different cross sections along gear facewidth. The Theory of Critical Distances used these stress gradients and material characteristics for fatigue crack initiation prediction. The benefits of presented methodology are shown by the detail analysis of the obtained results

Determination of critical size of corrosion pit on mechanical elements in hydro power plants

Researchers in the field of fracture mechanics, predominantly developing appropriate solution algorithms for problems of solid bodies with cracks. Problems in mechanics generally, related with fracture and fatigue for solid bodies with various geometries of sharp notches, are studied to a much lesser extent. This situation can be explained by analytical difficulties arising in solving problems of elasticity theory for bodies with rounded notches. To solve problems of such class, starting from data on stress concentration in the rounded notch tip with a significant radius of curvature, simplified solutions with are therefore of great importance. Recent years, due to constant rise of computing power and development of numerical methods, re-evaluation of stress concentration factors from a viewpoint of theory of elasticity is present. This is mainly as a feedback from industry, which have requirements toward mega and nanostructures. Corrosion represents an important limitation to the safe and reliable use of many alloys in various industries. Pitting corrosion is a form of serious damage on metals surface such as high-strength aluminum alloys and stainless steel, which are susceptible to pitting when exposed to a corrosive attack in aggressive environments. This is particularly valid for dynamic loaded structures. The basic idea behind this paper is finding links between different scientific and engineering disciplines, which will enable useful level of applicability of existing knowledge. The subject of this paper is application of new method of determine length scale parameter for estimating the mechanistic aspect of corrosion pit under uniaxial/multiaxial high-cycle fatigue loading…

Coupled nonlinear problems in finite element analysis: A case study

Rad daje opis analize elastoplastičnih deformacija čeličnog cevnog apsorbera kinetičke energije sudara železničkih vozila metodom konačnih elemenata (FEM). Eksperimentalna istraživanja korišćena su kao osnova za modeliranje i simulaciju FEM modela. Razvijeni model konačnih elemenata uključuje nelinearne karakteristike materijala (plastičnost), nelinearni kontakt i velike deformacije konačnih elemenata. Svi aspekti korišćeni u FEM modelu apsorbera detaljno su opisani. Rezultati FEM analize za izabrani apsorber prikazani su i analizirani. Razvijeni model otvara nove mogućnosti za buduća istraživanja u sličnim problemima.The paper describes the Finite Element Method (FEM) analysis of elastic plastic deformation of steel tube impact absorbers for railway vehicles. Experiment investigation is used as a basis for FEM modelling and simulation. The developed FEM model includes material nonlinearity (plasticity), nonlinear contact and large deformation of finite elements. All aspects used in the absorber FEM model are explained in detail. The finite element analysis results for a chosen absorber are presented and discussed. The developed model opens the possibilities for future investigations of similar problems

Efficiency and Market Share in the Banking Sector in South East European Countries

The banking sector in South East Europe Countries (SEECs) has changed dramatically from the start of the transition process. The change in market structure has been associated with a change in market shares of banks. This thesis investigates factors that determine a bank’s market share. According to the literature, the main determinant of a bank’s competitive position is its efficiency. Hence, the first part of the thesis investigates a bank’s efficiency and its determinants, while the second part uses these efficiency estimates along with other bank-specific factors and regulatory variables to investigate the determinants of a bank’s market share. The analyses are conducted in eight SEECs for the 2000-2012 period. Stochastic Frontier Analysis, specifically the Random Parameters Models (Greene, 2005) and the Battese and Coelli (1995) models, are employed for estimation of the bank’s cost efficiency. The empirical findings suggest that the choice of methods of investigation matters, with the Battese and Coelli models performing poorly, which supports the critique that these models are data dependent. The banking sector in Slovenia is the most efficient in the region while that in Serbia is the least efficient. The thesis then investigates the market share of banks which is argued to depend on “inside” bank determinants (cost efficiency, investment in quality of service, risk-taking, capital, ownership structure, etc.) and “outside” bank determinants (regulatory and supervisory practices and macroeconomic variables). A direct theory of market share is undeveloped in the literature; hence, several related strands of theory are examined to develop a model for estimation. It is argued that a bank’s market share is the result of a dynamic process; hence dynamic panel estimation is applied. The empirical findings suggest that the effect of efficiency on a bank’s market share depends on its size. Taking more risk, being a more capitalized bank relative to the industry average and investment in quality (expanding branch network) contribute to higher market share. Stringent capital requirements, private monitoring and official supervisory power are found to be associated with a less concentrated banking industry. However, the effects of regulation on bank-level market share are found to vary with different risk-taking behaviour of banks

Service life prediction of running steel wire ropes

Vrlo visoka čvrstoća omogućava žičanom užetu da prenese velike zatezne sile i da se kreće po koturima relativno malog prečnika. Žice od čelika vrlo visoke čvrstoće su postojale više od sto godina pre nego što su patentirane, kada je uveden specijalni postupak zagrevanja i usavršen postupak izvlačenja. Dalja poboljšanja posle toga su uvedena u relativno malim koracima. Žičana užad uvek imaju ograničen radni vek. Zbog toga ona moraju da se podvrgnu inspekciji i ispitaju u pravilnim intervalima da bi se zamenila znatno pre otkaza. Krajnji korisnik mašine sa čeličnim žičanim užetom u svakom slučaju želi da ima grubu ocenu radnog veka užeta već u ranoj fazi razvoja mašine. tako da bude u mogućnosti, ako zatreba, da poboljša sistem mašine. To je jedan od razloga zbog kojih su tokom niza godina izvedena obimna istraživanja kako bi se poboljšali postupci proračuna za predviđanje radnog veka žičanih užadi. Namena ovog rada je da ponudi pregled informacija o postupcima proračuna i da prikaže mogućnosti i ograničenja postupaka prognoziranja za predviđanja radnog veka čeličnih žičanih užadi u eksploataciji.Very high strength enables wire ropes to support large tensile forces and to run over sheaves with relative small diameters. Very high strength steel wires had already been in existence for more than a hundred years when patenting, a special heating process was introduced and the drawing process improved. Since then, further improvements have only occurred in relatively small steps. Wire ropes always have a limited service life. Therefore they must be inspected and examined at regular intervals so that they are replaced well before failure. End-users of machinery with steel wire ropes, however, would like to have a rough estimation of the service life of the ropes already in the early stages of conceiving their machines, so that they can, if necessary, improve the revving system. This is one of the reasons why for many years extensive research is carried out in order to improve calculations for predicting the service life of wire ropes. This paper is meant to offer an overview information on the method of calculation and to demonstrate the potential and limitations of the forecasting procedure for service-life prediction of running steel wire ropes