Micro: Bit as a Tool for Improvement of Education Stanojević, Dragana; Rosić, Aleksandra; Ranđelović, Branislav ...
International journal of management science and business administration,
2021, Letnik:
7, Številka:
2
Journal Article
Odprti dostop
Technical education and Computer science education is easier to understand and more meaningful to learn using new teaching materials. This paper describes the use of miniature Micro: bit computers, ...developed by the British company BBC, in cooperation with several technology companies, with a purpose to increase the number of technologically educated people. Paper presents possible use of Micro: bit in teaching technical and informatics education and its impact on the development of digital competence. Micro: bit is already used in schools in the UK and part of teachers in Serbia had the opportunity to get acquainted with characteristics of this device. It is shown how students can try out the programming in the Microsoft Block Editor. Another benefit of this mini-computer is getting to know the basics of robotics. The curriculum in primary education enables the use of such tools in teaching process. Use of this tool and others, similar to it, in work with students, creates the atmosphere in school that is oriented towards new technologies. The simplicity of this mini-computer allows the student to become familiar with different professional challenges that can help them with choosing a future profession.
In this paper, particular attention was paid to the presence of aerosol solid particles, which occurred mainly as a result of exploitation and coal combustion in the thermal power plants of the ...Kolubara basin. Not all of the particles created by this type of anthropogenic pollution have an equal impact on human health, but it largely depends on their size and shape. The mineralogical composition and particle size distribution in the samples of aero sediments were defined. The samples were collected close to the power plant and open pit coal mine, in the winter and summer period during the year 2007. The sampling was performed by using precipitators placed in eight locations within the territory of the Lazarevac municipality. In order to characterize the sedimentary particles, several methods were applied: microscopy, SEM-EDX and X-ray powder diffraction. The concentration of aero sediments was also determined during the test period. Variety in the mineralogical composition and particle size depends on the position of the measuring sites, geology of the locations, the annual period of collecting as well as possible interactions. By applying the mentioned methods, the presence of inhalational and respiratory particles variously distributed in the winter and in the summer period was established. The most common minerals are quartz and feldspar. The presence of gypsum, clay minerals, calcite and dolomite as secondary minerals was determined, as well as the participation of organic and inorganic amorphic matter. The presence of quartz as a toxic mineral has a particular impact on human health.
Coal fly ash was modified to zeolitic materials by hydrothermal treatment at 90 ?C. The zeolite synthesis was studied as a function of the mole ratio of Na2O/SiO2 in the reaction mixtures. The ...results showed that NaP1 zeolite is obtained when the Na2O/SiO2 mole ratio was 0.7. Hydroxysodalite is the dominant zeolite phase in modified fly ash treated with a higher Na2O concentration solution (Na2O/SiO2 = 1.3). The IR and XRD methods were used to determine the phases present in the starting sample and in the zeolitic materials.
Hidrotermalnim postupkom na 90 ?C leteci pepeo dobijen u termoelektrani (elektrofilterski pepeo) modifikovan je u materijale koji sadrze zeolite. U radu je ispitivana zavisnost tipa zeolita sintetizovanog primenom navedenog postupka od molskog odnosa Na2O/SiO2 u reakcionoj smesi. Rezultati su pokazali da se pri vrednosti Na2O/SiO2 = 0,7 u zeolitiziranom pepelu formira zeolit NaP1. Kada je taj odnos veci (Na2O/SiO2 = 1,3) kao dominantna zeolitna faza identifikovan je hidroksisodalit. Za analizu leteceg pepela kao polazne sirovine kao i zeolitiziranih materijala koriscene su metode infracrvene spektrofotometrije i rendgenske analize.
In this paper the results of the investigated properties of fly ash from four thermal power plants in Serbia are presented. The physical, chemical, mineralogical and thermal characterization of fly ...ash was carried out, in order to determine the possibility to utilize this material in the building materials industry, foremost in the cement industry. It was determined that, although there are differences concerning the physical, chemical, and mineralogical characteristics of the investigated samples, they are very similar concerning their thermal characteristics. It was concluded that using fly ash as one of the raw components in the mixture for Portland cement clinker synthesis, not only enables the substitution of natural resources, but it might have a positive effect on the lowering of the sintering temperature.
U ovom radu predstavljeni su rezultati ispitivanja svojstava elektrofilterskog pepela iz cetiri termoelektrane u Srbiji. Izvrsena je fizicka, hemijska, mineraloska i termicka karakterizacija elektrofilterskog pepela u cilju utvrdjivanja mogucnosti njegove upotrebe kao sirovine u industriji gradjevinskih materijala, pre svega u industriji cementa. Medju ispitivanim uzorcima elektrofilterskog pepela postoje odredjene razlike u pogledu fizickih, hemijskih i mineraloskih karakteristika, buduci da osobine pepela zavise od vrste uglja, uslova sagorevanja u peci, efikasnosti elektrofiltera i brojnih drugih faktora. Medjutim, ispitivani uzorci pepela su u pogledu termickih karakteristika veoma slicni. Zakljuceno je da upotreba elektrofilterskog pepela, kao jedne od komponenti sirovinske mesavine za proizvodnju portland-cementnog klinkera, ne samo da omogucava supstituciju prirodnih sirovina, nego bi mogla da ima i pozitivan uticaj na snizenje temperature sinterovanja portland-cementnog klinkera.
Influence of mechanical activation on quality of cement with addition of fly ash was investigated. The experiments of mechanical activation were performed in laboratorial vibro mill with rings. The ...effects of mechanical activation were determined by the comparative analyses of the starting cement and the same cement treated mechanically for 3, 10 and 30 min. The analyses included determination of the specific surface area, X-ray diffractometric analysis (XRD), differential-thermal analysis (DTA) and thermogravimetric analysis (TGA). During the 30-min comminution period, the specific surface area was increasing, while the microstructural changes of portland cement with fly ash addition (20% wt.) were intensified. DT and TG analyses show that endothermic and exothermic reactions proceed at the lower temperatures, which is an indication of increased reactivity of mechanically activated sample. Physico-mechanical properties significantly improved after only 3 min activation. After the 3-min activation, i.e., the seven-day solidification, the increase in the compression strength is very well-expressed. However, even after the 28-day solidification, the compression strength of mechanically activated sample was 58% higher, in comparison with inactivated sample of the same composition. Also, after the 28-day solidification, the compression strength of portland cement with addition of fly ash, mechanically activated for 3 min, was approximately the same to the compression strength of portland cement without additives.
Fly ash from four power plants in Serbia (PP "Morava" - Svilajnac, PP "Kolubara" - Veliki Grijani, PP "Kostolac" - units B1 and B2 - Kostolac and PP "Nikola Tesla" - units A and B - Obrenovac) was ...utilized as the starting raw component for Portland cement clinker synthesis. Limestone and quartz sand from the "Holcim - Serbia, a.d." cement factory were the other two starting raw components. Based on the chemical composition of the raw components and from the projected cement moduli, the amounts of raw components in the raw mixtures were calculated. Six different raw mixtures were prepared - each one consisted of limestone, sand and different fly ash. A raw mixture from the industrial production of the "Holcim - Serbia, a.d." cement factory was used as the reference material. The prepared raw mixtures were sintered in a laboratory furnace at 1400?C. The chemical and mineralogical compositions of the synthesized clinkers were determined. The characteristics of clinkers, based on fly ash, were compared to the characteristics of the industrial Portland cement clinker from the "Holcim - Serbia, a.d." cement factory. The results of the investigation showed that fly ash from power plants in Serbia can be suitable for Portland cement clinker synthesis.
Elektrofilterski pepeo iz cetiri termoelektrane u Srbiji (TE "Morava" - Svilajnac, TE "Kolubara" - Veliki Grijani, TE "Kostolac" blok B1 i B2 - Kostolac i TE "Nikola Tesla" blok A i B - Obrenovac) upotrebljen je kao polazna komponenta za sintezu portland-cementnog klinkera. Kao druge dve polazne komponente upotrebljeni su krecnjak i kvarcni pesak iz fabrike cementa "Holcim-Srbija, a.d.". Na bazi hemijskog sastava polaznih komponenti, kao i zadatih cementnih modula, izracunato je njihovo ucesce u sirovinskim mesavinama. Pripremljeno je sest razlicitih sirovinskih mesavina - svaka se sastojala iz krecnjaka, peska i razlicitog elektrofilterskog pepela. Kao referentni materijal koriscena je sirovinska mesavina iz industrijske proizvodnje fabrike cementa "Holcim-Srbija, a.d". Pripremljene sirovinske mesavine sinterovane su u laboratorijskoj peci na 1400?C. Sintetizovani klinkeri analizirani su u pogledu hemijskog i mineralnog sastava. Karakteristike sintetizovanih klinkera na bazi elektrofilterskog pepela, uporedjene su sa karakteristikama industrijskog portland-cementnog klinkera iz fabrike cementa "Holcim-Srbija, a.d.". Rezultati istrazivanja pokazali su da je elektrofilterski pepeo iz termoelektrana Srbije pogodan za dobijanje portland-cementnog klinkera.
This paper describes the physical, chemical and mineral properties of ash and slag, which were taken from thermal power plants Nikola Tesla A, Nikola Tesla B, Kostolac A and Kostolac B. The knowledge ...of the mineralogical material composition is important because the type of minerals directly determines the properties of the fly ash and slag and their possible application. Laboratory tests showed that ash and slag samples consist of the following minerals: amorphous materials, quartz, feldspar, mullite, melilite, cristobalite, haematite and calcite. The fly ash and slag chemical properties are the most important indicators in the evaluation of their suitability as a building material. The ash and slag chemical composition is composed of the following chemical components: SiO^sub 2^, Al^sub 2^O^sub 3^, Fe^sub 2^O^sub 3^, CaO, MgO, SO^sub 3^, S, Na^sub 2^O and K^sub 2^O. Results of laboratory tests show that fly ash and slag have variable chemical, mineralogical and physical properties that are dependent on the natural composition, quality of coal from basin, the manner of combustion and place of ash deposition.
Fly ash is one of the most common waste materials created by burning of coal. It is composed of smaller particles, consisting mainly of aluminosilicate-glass, mullite and quartz, which are collected ...by electrostatic separators (filter) of gaseous products arising from the combustion of coal. This paper presents the pozzolanic properties, mechanical properties, chemical and mineral composition of fly ash obtained in the combustion process in a power plant Nikola Tesla A (PPNT A) with the addition of a binder hydrated lime and cement. The aim of research is to test the possibility of using the fly ash from PPNT A for making elements of road structures (top and bottom layers of the road). Fly ash can be used to create elements for road structures, but it must be taken into account that the embedding is done in segments, isolated from the influence of surface water and groundwater.
Elektrofilterski pepeo (leteći pepeo) je jedan od najzastupljenijih otpadnih materijala nastao sagorijevanjem uglja. Čine ga sitnije čestice, sastoji se uglavnom od amorfno-staklastog materijala, ...mulita i kvarca, koji se sakuplja elektrostatičkim separatorima (filterima) iz plinovitih produkata nastalih uslijed sagorijevanja uglja. U radu su prikazana pucolanska svojstva, mehanička svojstva, kemijski i mineralni sastav i svojstva elektrofilterskog pepela dobivenog u procesu sagorijevanja u termoelektrani Nikola Tesla A (TENT A) s dodatkom veziva hidratiziranog vapna i cementa. Cilj istraživanja je mogućnost uporabe elektrofilterskog pepela za izradu elemenata cestovnih konstrukcija (gornji i donji stroj puta). Elektrofilterski pepeo se može primjenjivati za izradu elemenata cestovne konstrukcije, ali treba voditi računa da se ugrađivanje odvija u segmentima, izoliranim od utjecaja površinskih i podzemnih voda.
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