Motives and Characteristics of Highly Qualified Labor Force Migration: Case Study of Serbia

The emigration of highly qualified labour from the countries of Eastern Europe is one of the worst effects of transitional and post-transitional period. It discredits the educational system of Eastern European countries, but also creates long-term problems in the development of the economy and all other sectors of society. The difference in earnings between immigrant countries of Western Europe and North America and the countries of emigration is the dominant motive for migration. But other motives are also not irrelevant. This paper is an initial part of a wider research of the international movement of labour which should provide guidance to the countries of emigration to mitigate  the consequences of this process. Student surveys in Eastern European countries, their thoughts and plans, will provide information on the motives of emigration. On the other hand, by surveying the experiences of young highly educated workforce who has already emigrated, a true picture of experiences and the expected and achieved intentions will be obtained. Finally, certain questions in the questionnaire will also give an answer to the question, which would be new moments that would encourage young experts not to leave the country, or to return those who emigrated. Keywords: International migration, brain drain, state measures, retaining talen

Designing With BIM Tools Using Sustainability Criteria

A new breakthrough era in design has begun in whole building industry, which is based on BIM – Building Information Model. The emphasis of the new workflow is in information stored inside building model which is used in BIM-based software from where all designers get the needed data and work on. A change from designing on paper to designing in CAD (Computer Aided Design) software was a big change, although it actually just changed the normal paper with digital one. While on the other hand BIM is said by many to be a much bigger change in the way things work in building industry. The thesis focuses on the possibilities of BIM in building design regarding buildings’ energy efficiency and sustainability, which is becoming more and more important nowadays because of the climate change. There are many BIM software providers, but currently the most popular of them all in worldwide comparison is Revit from American corporation Autodesk. Software package contains three applications – Revit Architecture (for architects), Revit Structure (for structural engineers) and Revit MEP (for MEP engineers). There are many other specialized software applications which can work with Revit, but when we are considering sustainable design there are two programs from Autodesk which stand out – Ecotect Analysis and Green Building Studio (GBS). The thesis outlines history and development of BIM design and stresses out the importance in possibility of software interoperability and plots the basics of sustainable design in BIM. After that, description of modeling reinforced concrete structure of chosen building is shown in Revit Architecture 2010. The first goal of the thesis was modeling a whole detailed architectural model of the building, but when we realized the importance of using sustainable design analysis software is in the conceptual phase of design, we dropped that goal. The thesis then shows how a conceptual design of the building is modeled and then used in further study inside Ecotect Analysis 2010 and GBS. The study in Ecotect shows average daily insulation analysis and overshadowing of the building. GBS’s study shows possibilities and results of VII

Promjene intraokularnog tlaka nakon nekomplicirane fakoemulzifikacije u ranom poslijeoperacijskom razdoblju u zdravim očima

The aim was to determine early changes in intraocular pressure (IOP) following uneventful phacoemulsifi-cation and intraocular lens (IOL) implantation in healthy eyes. This prospective interventional case series study was conducted at Ophthalmology Department, Kragujevac Clinical Centre, Kragujevac, Serbia. The study included 123 eyes of 123 cataract patients, 66 women and 57 men, age range 50-88 (mean 70.73±7.94) years having undergone phacoemulsification and in-the-bag implantation of a foldable IOL. The patients were treated at Kragujevac Clinical Centre between June 2015 and May 2016. IOP was measured by Goldmann applanation tonometry preoperatively, then 4-6 hours, 18-24 hours and 7 days postoperatively by the same examiner. The mean IOP preoperatively was 15.10±2.68 mm Hg. In three patients, maximum measured IOP was 22 mm Hg. At 4-6 hours postoperatively, the mean IOP was 24.29±7.56 mm Hg (p<0.001), at 18-24 hours it was 18.37±4.80 mm Hg (p<0.001), and 7 days after the surgery the mean IOP was 16.24±2.90 mm Hg (p<0.05). The measured IOP values were statistically signif-icant in all measured times. However, at 4-6 hours and 18-24 hours, the mean IOP value was highly statis-tically significant (p<0.001). Although 7 days after the surgery IOP normalized, the mean IOP value was statistically significant (p<0.05). In conclusion, our research showed that even eyes with normal preopera-tive values and uncomplicated phacoemulsification course can show very high IOP values postoperative-ly, which can cause pain, blurred vision and, rarely, compromise visual function.Cilj rada je bio utvrditi rane promjene intraokularnog tlaka (IOT) nakon fakoemulzifikacije i implantacije intraoku-larne leće (IOL) u zdrave oči. Ova prospektivna interventna studija slučaja provedena je na Oftalmološkom odjelu Kliničkog centra Kragujevac u Kragujevcu, Srbija. Studija je obuhvatila 123 oka bolesnika s kataraktom, 66 žena i 57 muškaraca, u dobi od 50-88 (srednja dob 70,73±7,94) godina, koji su bili podvrgnuti fakoemulzifikaciji i implan-taciji IOL u kapsularnu vrećicu. Bolesnici su liječeni u Kliničkom centru Kragujevac između lipnja 2015. i svibnja 2016. godine. IOT je mjeren Goldmannovim aplanacijskim tonometrom prijeoperacijski, a zatim 4-6 sati, 18-24 sata i 7 dana poslijeperacijski, a mjerenja je obavio isti ispitivač. Srednja vrijednost IOT prijeoperacijski je iznosila 15,10±2,68 mm Hg. Kod tri bolesnika najviši izmjereni IOT bio je 22 mm Hg. Kod mjerenja provedenog 4-6 sati poslijeoperacijski srednja vrijednost IOT bila je 24,29±7,56 mm Hg (p<0,001), zatim u 18-24 sata bila je 18,37±4,80 mm Hg (p<0,001), a 7 dana nakon operacije srednja vrijednost IOT bila je 16,24±2,90 mm Hg (p<0,05). Izmjerene vrijednosti IOTbile su statistički značajne u svim vremenima mjerenja. Međutim, u 4-6 sati i 18-24 sata srednja vrijednost IOT bila je visoko statistički značajna (p<0,001). Iako se 7 dana nakon operacije vrijednost IOT normali-zirala, srednja vrijednost je bila statistički značajna (p<0,05). U zaključku, naše istraživanje je pokazalo da čak i oči s normalnim prijeoperacijskim vrijednostima i nekompliciranim tijekom fakoemulzifikacije mogu pokazivati vrlo visoke vrijednosti IOT, što može uzrokovati bol, zamagljen vid i, rijetko, ugroziti vidnu oštrinu

Analytical and experimental determination of the temperature field on the surface of wall heating panels

This paper presents experimental verification of the accuracy and acceptability of Faxen-Rydberg-Huber analytical expression for determining thermal characteristics of the heating panels. The verification of accuracy of the Faxen-Rydberg-Huber expression, which describes the 2-D temperature field in the wall with series of embedded heated pipes having uniform temperature, was performed by comparing the temperatures on the surface of three types of heating wall panels, differing in structure and geometric characteristics. The analysis of results has shown high accuracy of Faxen-Rydberg-Huber expression in describing the temperature field. Also, it was noted that small changes in heating fluid temperature, occurring along the pipe in the heated panel, have a negligible influence on the accuracy of prediction by the expression. This confirmed that the Faxen-Rydberg-Huber expression can be used to describe the temperature field in the wall heating panels. At the same time, this expression has proven to be extremely sensitive primarily to thermophysical characteristics of the panel layers, as well as to the geometric parameters of the panels

Analytical and experimental determination of the temperature field on the surface of wall heating panels

This paper presents experimental verification of the accuracy and acceptability of Faxen-Rydberg-Huber analytical expression for determining thermal characteristics of the heating panels. The verification of accuracy of the Faxen-Rydberg-Huber expression, which describes the 2-D temperature field in the wall with series of embedded heated pipes having uniform temperature, was performed by comparing the temperatures on the surface of three types of heating wall panels, differing in structure and geometric characteristics. The analysis of results has shown high accuracy of Faxen-Rydberg-Huber expression in describing the temperature field. Also, it was noted that small changes in heating fluid temperature, occurring along the pipe in the heated panel, have a negligible influence on the accuracy of prediction by the expression. This confirmed that the Faxen-Rydberg-Huber expression can be used to describe the temperature field in the wall heating panels. At the same time, this expression has proven to be extremely sensitive primarily to thermophysical characteristics of the panel layers, as well as to the geometric parameters of the panels

Experimental determination of thermal conductivity of soil with a thermal response test

Optimal design of a borehole heat exchanger, as the outer part of a ground source heat pump heating system, requires information on the thermal properties of the soil. Those data, the effective thermal conductivity of the soil leff and the average temperature of the soil T0, enable us to determine the necessary number and depth of boreholes. The determination of thermal conductivity of the soil in laboratory experiments does not usually coincide with the data under in situ conditions. Therefore, an in-situ method of experimental determination of these parameters, the so-called thermal response test, is presented in this paper. In addition to the description of the experimental procedure and installation overview, the paper describes methods based on theory and presents their basic limitations, through the presentation of experimental data

Achieving savings by implementation of efficient hybrid heating systems

Regarding to the structure of final energy consumption in buildings and National Action Plans, the paper gives a short overview of energy consumption in buildings in Serbia, showing that the greatest potential for achieving savings lies in the implementation of measures which improve energy efficiency. Considering that over 60% of energy requirements for buildings is related to thermal energy, particular attention should be paid to the centralized heating systems, both during the design of a new system, and in the reconstruction of the existing one. Further discussed are the heat sources for the heating systems. The seasonal heat load duration curve for winter conditions in accordance to the Typical Meteorological Year for Belgrade is constructed and displayed. The analysis of the conventional system with a fossil fuel source, as well as the analysis of a hybrid heat source are conducted. The savings achieved in the primary energy, heating bills and CO2 emission reduction, which are attained by the use of a hybrid system, are shown in comparison with the conventional systems. Collecting data on investment costs, as well as the prices of energy and fuels in Serbian market, enabled calculation of the payback period when replacing the conventional system by the new hybrid one

Achieving savings by implementation of efficient hybrid heating systems

Regarding to the structure of final energy consumption in buildings and National Action Plans, the paper gives a short overview of energy consumption in buildings in Serbia, showing that the greatest potential for achieving savings lies in the implementation of measures which improve energy efficiency. Considering that over 60% of energy requirements for buildings is related to thermal energy, particular attention should be paid to the centralized heating systems, both during the design of a new system, and in the reconstruction of the existing one. Further discussed are the heat sources for the heating systems. The seasonal heat load duration curve for winter conditions in accordance to the Typical Meteorological Year for Belgrade is constructed and displayed. The analysis of the conventional system with a fossil fuel source, as well as the analysis of a hybrid heat source are conducted. The savings achieved in the primary energy, heating bills and CO2 emission reduction, which are attained by the use of a hybrid system, are shown in comparison with the conventional systems. Collecting data on investment costs, as well as the prices of energy and fuels in Serbian market, enabled calculation of the payback period when replacing the conventional system by the new hybrid one

Analiza vezane energije i emisije CO2 za izvođenje mostovske konstrukcije sa stanovišta održivosti

This paper presents a comparative analysis of embodied energy and CO2 emission, in the construction process of three bridge structures. Analyzed structures are prestressed concrete bridges with different structural systems and a total length of 88 meters. The correlation of structural system, construction method, material quantities and embodied energy and CO2 emission were considered. Influence of the selected solutions in main steps of design and construction on the energy consumption and the emission of CO2 is presented. The results should provide a better understanding of the effects of certain factors, in the bridge construction process, and their impact on the environment.U radu je prikazana uporedna analiza vezane energije i emisije CO2 u procesu gradnje, za tri mostovske konstrukcije. Analizirane konstrukcije su prethodno napregnuti betonski mostovi, različitih statičkih sistema, ukupne dužine 88 metara. Razmatrana je međusobna uslovljenost izbora konstruktivnih rešenja, načina izvođenja konstrukcije, količine utrošenog materijala, vezane energije i emisije CO2. Dat je uvid u način na koji se glavni koraci u projektovanju i izvođenju mostova odražavaju na energetski utrošak i emisiju CO2, procentualno i u ukupnom iznosu. Dobijeni rezultati bi trebalo da omoguće bolje sagledavanje uticaja pojedinih faktora u procesu izvođenja mostova i njihov uticaj na životnu sredinu

Experimental and statistical survey on local thermal comfort impact on working productivity loss in university classrooms

The paper presents an experimental analysis of the relationship between local thermal comfort and productivity loss in classrooms. The experimental investigation was performed in a real university classroom during the winter semester in city of Belgrade. Measurements were taken for four scenarios, with different indoor comfort conditions. Variations were made by setting the central heating system on/off, adding an additional heat source to provoke higher indoor temperatures, and measuring the radiant asymmetry impact. Innovative questionnaires were developed especially for the research, in order to investigate students' subjective feelings about local thermal comfort and indoor environmental quality Local predicted mean vote and predicted percentage dissatisfied indices were calculated using data measured in situ. The results were compared to existing models recommended in literature and European and ASHRAE standards. Student productivity was evaluated using novel tests, designed to fit the purposes of the research. Surveys were conducted for 19 days under different thermal conditions, during lectures in a real classroom, using a sample of 240 productivity test results in total. Using the measured data, new correlations between the predicted mean vote, CO2, personal factor and productivity loss were developed. The research findings imply that local thermal comfort is an important factor that can impact productivity, but the impact of the personal factor is of tremendous importance, together with CO2 concentration in the classroom