Прегледај по Аутор "Spaić, Obrad"

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    APPLICATION VALIDITY OF THE TECHNOLOGICAL PROCEDURE FOR MAKING SPIRAL DRILL-BIT GROOVES
    (Institute for metallic materials and technology, 2021) Spaić, Obrad; Vukčević, Milan; Marinović, Budimirka; Koprivica, Aleksandra; Jovanović, Janko
    The current world trends and the global market require production organizations to increase the quality while reducing the costs of their products. In most cases, traditional production technologies of spiral drill bits (SD) cannot meet these expectations, as they most often fulfil only one of the set requirements. Thus, the cost of a SD produced with the rolling technology is low, but its quality is also much lower than that of the drills produced with the grinding technology whose cost is also much higher. The grooves of the SDs produced with our new technological method have advantages over the grooves produced with the rolling technology or grinding technology, and the savings in the material and grinding wheel are higher compared to the SDs produced with the grinding technology. This paper presents an analysis of the application of this new technological process for producing SD grooves
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    DESIGN OF THE NEW TECHNOLOGICAL PROCEDURE OF PRODUCING GROOVE OF SPIRAL BITS
    (Center for Quality, Faculty of Engineering, University of Kragujevac, Serbia,, 2020) Spaić, Obrad; Krivokapić, Zdravko; Marinović, Budimirka; Jovanović, Janko
    One of the most commonly used and at the same time the most complicated cutting tools in terms of body geometry is the spiral drill bit. In the process of their production, the key operation is the production of spiral grooves. Until now, the grooves on the drill bits have been mainly produced by milling, grinding, rolling and extrusion processes. All these procedures have their advantages and disadvantages as well. Based on the experimental measurements of the dimensions of the grooves of the drill bits produced by the rolling and grinding technology, the paper defines the basic parameters and a new technological procedure for the production of grooves of the drill bits has been designed. For the suggested technological procedure of making of grooves of the drill bits, the advantages and disadvantages of the conventional production of the grooves of the drill bits by rolling or grinding technology have been analysed.
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    Procjena bilansa emisije CO2 iz termoelektrana sa količinom apsorbovanog CO2 šumama u Republici Srpskoj
    (Faculty of Production and Management Trebinje, University of East Sarajevo, 2024-04-26) Vasković, Srđan; Tanić, Ljubiša; Adžić, Stefan; Jović, Borislav; Krunić, Gojko; Spaić, Obrad
    This paper deals with the comparison of the amount of carbon dioxide emitted from thermal power plants in the Republic of Srpska with the amount of CO2 absorbed in the process of photosynthesis through existing wood stocks in forests and the achieved wood growth of forests in the territory of the Republic of Srpska. Since CO2 by definition has a negative impact on the climate on planet Earth and due to the fact that it causes the greenhouse effect, additional warming of our planet occurs. There are generally two procedures for estimating and determining CO2 emissions from thermal power plants: based on previously defined mathematical models and measured coal consumption. The measurement methods used for taking samples are: nonextractive (measuring probes and devices are located inside or in the smoke duct) and extractive (the sample is taken from the smoke duct and taken to the device where it is analyzed). Sensors based on which the composition is determined are divided into: electrolytic, optical, calorimetric and photometric. The calculated and predicted emissions from the existing thermal power plants in the Republic of Srpska were compared with the equivalent of CO2 storage in the forest biomass that the Republic of Srpska has at its disposal, from which were derived very interesting parts of the conclusions regarding the CO2 neutrality of the energy sector related to the thermal power plants of the Republic of Srpska.