TY  - JOUR
AU  - Koprivica, Ranko
AU  - Veljković, Biljana
AU  - Turan, Jan
AU  - Radivojević, Dušan
AU  - Ćurčić, Srećko
AU  - Mileusnić, Zoran
AU  - Balalić, Igor
PY  - 2019
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/5146
AB  - Knowing the coefficient of friction of bio material is important in determining the angle of the grain elevator elevator when designing combines, as well as the angles of gravity tables and pipes in seed finishing. The basic characteristic of biological materials, or seeds of agricultural crops, is that they differ in their physical and morphological characteristics. Therefore, the friction depends on: the types of plants, variety, shape, dimensions and seed content, the humidity of the seed, the intensity of the normal force on the substrate and the roughness of the substrate. The paper presents the results of the study of the influence of individual factors (varieties, water content of the grain and the type of substrate) and their interactions on the grain friction coefficient. The domestic varieties that are grown in Serbia are selected for testing the fruiting grain fruity: Banadanka, Jasna and Slavica. The experimental measurement of the static coefficient of grain slip friction was done using the level of the mechanical device Tribometr. Plastic, plywood, galvanized, steel, aluminum and stainless steel sheet are made for the experiment purposes. Research was carried out with different water content in grains: 6%, 11%, 16% and 24%. The variety Banadanka had a lower friction coefficient compared to Jasna and Slavica varieties on all substrates and with all the water content of the grain. It was found that with the increase of water content in the grain, a significant increase in the friction coefficient of the grains of the tested varieties on all substrates was achieved. The highest friction coefficient for all water content of the grains of the tested varieties was on the base of the plywood board, and the smallest on the base of stainless steel sheet.
T2  - 16th International Conference on Tribology
T1  - Coefficient of explosion of grape oil repas in respect of variety, content of humidity and surface
EP  - 525
IS  - 1
SP  - 518
VL  - 1
DO  - 10.24874/PES01.01.068
ER  - 

@article{
author = "Koprivica, Ranko and Veljković, Biljana and Turan, Jan and Radivojević, Dušan and Ćurčić, Srećko and Mileusnić, Zoran and Balalić, Igor",
year = "2019",
abstract = "Knowing the coefficient of friction of bio material is important in determining the angle of the grain elevator elevator when designing combines, as well as the angles of gravity tables and pipes in seed finishing. The basic characteristic of biological materials, or seeds of agricultural crops, is that they differ in their physical and morphological characteristics. Therefore, the friction depends on: the types of plants, variety, shape, dimensions and seed content, the humidity of the seed, the intensity of the normal force on the substrate and the roughness of the substrate. The paper presents the results of the study of the influence of individual factors (varieties, water content of the grain and the type of substrate) and their interactions on the grain friction coefficient. The domestic varieties that are grown in Serbia are selected for testing the fruiting grain fruity: Banadanka, Jasna and Slavica. The experimental measurement of the static coefficient of grain slip friction was done using the level of the mechanical device Tribometr. Plastic, plywood, galvanized, steel, aluminum and stainless steel sheet are made for the experiment purposes. Research was carried out with different water content in grains: 6%, 11%, 16% and 24%. The variety Banadanka had a lower friction coefficient compared to Jasna and Slavica varieties on all substrates and with all the water content of the grain. It was found that with the increase of water content in the grain, a significant increase in the friction coefficient of the grains of the tested varieties on all substrates was achieved. The highest friction coefficient for all water content of the grains of the tested varieties was on the base of the plywood board, and the smallest on the base of stainless steel sheet.",
journal = "16th International Conference on Tribology",
title = "Coefficient of explosion of grape oil repas in respect of variety, content of humidity and surface",
pages = "525-518",
number = "1",
volume = "1",
doi = "10.24874/PES01.01.068"
}

Koprivica, R., Veljković, B., Turan, J., Radivojević, D., Ćurčić, S., Mileusnić, Z.,& Balalić, I.. (2019). Coefficient of explosion of grape oil repas in respect of variety, content of humidity and surface. in 16th International Conference on Tribology, 1(1), 518-525.
https://doi.org/10.24874/PES01.01.068

Koprivica R, Veljković B, Turan J, Radivojević D, Ćurčić S, Mileusnić Z, Balalić I. Coefficient of explosion of grape oil repas in respect of variety, content of humidity and surface. in 16th International Conference on Tribology. 2019;1(1):518-525.
doi:10.24874/PES01.01.068 .

Koprivica, Ranko, Veljković, Biljana, Turan, Jan, Radivojević, Dušan, Ćurčić, Srećko, Mileusnić, Zoran, Balalić, Igor, "Coefficient of explosion of grape oil repas in respect of variety, content of humidity and surface" in 16th International Conference on Tribology, 1, no. 1 (2019):518-525,
https://doi.org/10.24874/PES01.01.068 . .

TY  - CONF
AU  - Koprivica, Ranko
AU  - Turan, Jan
AU  - Veljković, Biljana
AU  - Radivojević, Dušan
AU  - Bokan, Nikola
AU  - Durović, Dragan
AU  - Dokić, Dragoslav
AU  - Balalić, Igor
PY  - 2018
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/4707
AB  - The physical properties of the three common cultivars were evaluated as a function of seed moisture content, which varied from 6.04 - 21.17%, from 5.82 - 20.90% and from 5.98 - 20.46% in 'Banacanka', 'Jasna' and 'Slavica', respectively. Results of thousand-seed weight increased from 4.18 g to 4.94 g in 'Banacanka', from 4.74 g to 5.61 g in 'Jasna', and from 4.11 to 4.81 g in 'Slavica'. The seed volume of 'Jasna' ranged between 4.72 mm(3) and 5.49 mm(3), and it was significantly higher than that of 'Banacanka' and 'Slavica' (4.07 - 4.93 mm(3) and 4.12 - 4.81 mm(3), respectively). The bulk density of 'Jasna' seeds was significantly lower than in other cultivars. Depending on seed moisture content, seed density decreased from 1023.18 kgm(-3) to 996.97 kgm(-3) in 'Banacanka', from 1009.31 to 992.70 kgm(-3) in 'Jasna', and from 1012.96-992 kgm(-3) in 'Slavica'. Porosity increased with increasing seed moisture content in all cultivars. The porosity of 'Jasna' seeds (35.97-38.43%) was higher than that of 'Banacanka' (35.42-38.23%) and 'Slavica' (35.19-37.07%) seeds. At different seed moisture levels, bulk density varied from 665.82 to 615.84 kgm(-3) in 'Banacanka', from 646.24 to 611.22 kgm(-3) in 'Jasna', and from 656.57 to 624.66 kgm(-3) in 'Slavica'. The static angle of repose in 'Banacanka', 'Jasna' and 'Slavica' ranged from 22.96 degrees to 28.05 degrees, from 24.64 degrees to 29.66 degrees and from 24.63 degrees to 29.61 degrees at moisture contents increasing. The dynamic angle of repose was highest in 'Jasna' (20.32-25.90 degrees), followed by 'Slavica' (21.03-25.58 degrees), and lowest in 'Banacanka' (19.22-24.66 degrees). Increasing seed moisture content was found to increase the friction coefficient. The static friction coefficient of cvs. 'Jasna' and 'Slavica' was higher than for 'Banacanka'.
PB  - Agronomski fakultet Sveucilista u Zagrebu, 10000 Zagreb
C3  - Actual Tasks on Agricultural Engineering
T1  - Physical properties of oil rapeseed kernels at different moisture content and varietes
EP  - 405
SP  - 397
VL  - 46
UR  - https://hdl.handle.net/21.15107/rcub_agrospace_4707
ER  - 

@conference{
author = "Koprivica, Ranko and Turan, Jan and Veljković, Biljana and Radivojević, Dušan and Bokan, Nikola and Durović, Dragan and Dokić, Dragoslav and Balalić, Igor",
year = "2018",
abstract = "The physical properties of the three common cultivars were evaluated as a function of seed moisture content, which varied from 6.04 - 21.17%, from 5.82 - 20.90% and from 5.98 - 20.46% in 'Banacanka', 'Jasna' and 'Slavica', respectively. Results of thousand-seed weight increased from 4.18 g to 4.94 g in 'Banacanka', from 4.74 g to 5.61 g in 'Jasna', and from 4.11 to 4.81 g in 'Slavica'. The seed volume of 'Jasna' ranged between 4.72 mm(3) and 5.49 mm(3), and it was significantly higher than that of 'Banacanka' and 'Slavica' (4.07 - 4.93 mm(3) and 4.12 - 4.81 mm(3), respectively). The bulk density of 'Jasna' seeds was significantly lower than in other cultivars. Depending on seed moisture content, seed density decreased from 1023.18 kgm(-3) to 996.97 kgm(-3) in 'Banacanka', from 1009.31 to 992.70 kgm(-3) in 'Jasna', and from 1012.96-992 kgm(-3) in 'Slavica'. Porosity increased with increasing seed moisture content in all cultivars. The porosity of 'Jasna' seeds (35.97-38.43%) was higher than that of 'Banacanka' (35.42-38.23%) and 'Slavica' (35.19-37.07%) seeds. At different seed moisture levels, bulk density varied from 665.82 to 615.84 kgm(-3) in 'Banacanka', from 646.24 to 611.22 kgm(-3) in 'Jasna', and from 656.57 to 624.66 kgm(-3) in 'Slavica'. The static angle of repose in 'Banacanka', 'Jasna' and 'Slavica' ranged from 22.96 degrees to 28.05 degrees, from 24.64 degrees to 29.66 degrees and from 24.63 degrees to 29.61 degrees at moisture contents increasing. The dynamic angle of repose was highest in 'Jasna' (20.32-25.90 degrees), followed by 'Slavica' (21.03-25.58 degrees), and lowest in 'Banacanka' (19.22-24.66 degrees). Increasing seed moisture content was found to increase the friction coefficient. The static friction coefficient of cvs. 'Jasna' and 'Slavica' was higher than for 'Banacanka'.",
publisher = "Agronomski fakultet Sveucilista u Zagrebu, 10000 Zagreb",
journal = "Actual Tasks on Agricultural Engineering",
title = "Physical properties of oil rapeseed kernels at different moisture content and varietes",
pages = "405-397",
volume = "46",
url = "https://hdl.handle.net/21.15107/rcub_agrospace_4707"
}

Koprivica, R., Turan, J., Veljković, B., Radivojević, D., Bokan, N., Durović, D., Dokić, D.,& Balalić, I.. (2018). Physical properties of oil rapeseed kernels at different moisture content and varietes. in Actual Tasks on Agricultural Engineering
Agronomski fakultet Sveucilista u Zagrebu, 10000 Zagreb., 46, 397-405.
https://hdl.handle.net/21.15107/rcub_agrospace_4707

Koprivica R, Turan J, Veljković B, Radivojević D, Bokan N, Durović D, Dokić D, Balalić I. Physical properties of oil rapeseed kernels at different moisture content and varietes. in Actual Tasks on Agricultural Engineering. 2018;46:397-405.
https://hdl.handle.net/21.15107/rcub_agrospace_4707 .

Koprivica, Ranko, Turan, Jan, Veljković, Biljana, Radivojević, Dušan, Bokan, Nikola, Durović, Dragan, Dokić, Dragoslav, Balalić, Igor, "Physical properties of oil rapeseed kernels at different moisture content and varietes" in Actual Tasks on Agricultural Engineering, 46 (2018):397-405,
https://hdl.handle.net/21.15107/rcub_agrospace_4707 .

TY  - JOUR
AU  - Koprivica, Ranko
AU  - Veljković, Biljana
AU  - Turan, Jan
AU  - Pajić, Miloš
AU  - Miodragović, Rajko
AU  - Radojević, Rade
PY  - 2014
UR  - http://aspace.agrif.bg.ac.rs/handle/123456789/3566
AB  - The biggest problem in seed birdsfoot trefoil harvest is pod cracking before and during harvest. At full maturity, birdsfoot trefoil pods crack easily, resulting in seed spillage and hence seed losses. The cracking pod problem significantly limits the successful production of seeds. Exploitation indices, operational performance and reliability of a used general-purpose Claas Mercator 50 combine harvester in harvesting birdsfoot trefoil seed were studied. The testing was carried out in field conditions in Western Serbia area. The losses of grain over the cutter bar and over the threshing machine were found out.Total header and thresher losses ranged from 21.28% to 23.86% at an operating speed of 2.04 km/h and 2.63 km/h, respectively. This is an expected result for the crop under increased crop moisture conditions. There was loss of operating time i.e. congestion of unharvested grain due to increased operating rate, seed moisture and straw. Time consumption for elimination of harvesting delay at a rate of 2.63 km/h was higher than at a rate of 2.04 km/h and accounted for 13.48% of the total operating time. The research also involved monitoring of intensity pod cracking during the day depending on air temperature. Birdsfoot trefoil pod opening intensity increased of starts after 11 a.m. at air temperatures over 30 0 C when 80-90% of pods crack at 17- 20% moisture.
AB  - U žetvi semena žutog zvezdana najveći problem predstavlja otvaranje mahuna pre i toku žetve. U punoj zrelosti mahune žutog zvezdana lako se otvaraju i seme se prosipa što dovodi do gubitaka. Problem otvaranja mahuna u značajnoj meri limitira uspešnu proizvodnju semena. Istraživani su eksplatacioni pokazatelji, kvalitet rada i pouzdanost starog univerzalnog žitnog kombajna 'Claas Mercator 50' u žetvi semena žutog zvezdana. Ispitivanje je obavljeno u poljskim uslovima Zapadne Sbije. Ustanovljeni su gubici na hederu i vršalici kombajna. Ukupni gubici hedera i vršalice na ispitivanom kombajnu iznosili su od 21,28% do 23,86% pri radnim brzinama 2,04 km/h i 2,63 km/h, što se moglo i očekivati za pomenuti kombajn i ovu kulturu u uslovima povećane vlažnosti useva. Tokom rada kombajna dolazilo je do zastoja tj. zagušenja vršidbene mase, usled povećane radna brzina, vlažnosti semena i slame. Utrošeno vreme za otklanjanje tehnoloških zastoja kod radne brzine od 2,63 km/h bilo je veće nego kod brzine od 2,04 km/h i iznosilo je 13,48% od ukupnog radnog vremena. Intenzitet pucanja u toku dana zavisno od temperature je takođe bio predmet ispitivanja ovog rada. Povećani intenzitet otvaranja mahuna počinje posle 11 sati, pri temperaturi vaduha preko 30 0 C kada se otvori 80-90% mahuna vlažnosti od 17- 20%.
PB  - Nacionalno naučno društvo za poljoprivrednu tehniku, Novi Sad
T2  - Savremena poljoprivredna tehnika
T1  - Single phase harvest of birdsfoot trefoil seed by general-purpose combine harvesters
T1  - Jednofazna žetva semena žutog zvezdana univerzalnim žitnim kombajnom
EP  - 160
IS  - 3
SP  - 151
VL  - 40
DO  - 10.5937/SavPoljTeh1403151K
ER  - 

@article{
author = "Koprivica, Ranko and Veljković, Biljana and Turan, Jan and Pajić, Miloš and Miodragović, Rajko and Radojević, Rade",
year = "2014",
abstract = "The biggest problem in seed birdsfoot trefoil harvest is pod cracking before and during harvest. At full maturity, birdsfoot trefoil pods crack easily, resulting in seed spillage and hence seed losses. The cracking pod problem significantly limits the successful production of seeds. Exploitation indices, operational performance and reliability of a used general-purpose Claas Mercator 50 combine harvester in harvesting birdsfoot trefoil seed were studied. The testing was carried out in field conditions in Western Serbia area. The losses of grain over the cutter bar and over the threshing machine were found out.Total header and thresher losses ranged from 21.28% to 23.86% at an operating speed of 2.04 km/h and 2.63 km/h, respectively. This is an expected result for the crop under increased crop moisture conditions. There was loss of operating time i.e. congestion of unharvested grain due to increased operating rate, seed moisture and straw. Time consumption for elimination of harvesting delay at a rate of 2.63 km/h was higher than at a rate of 2.04 km/h and accounted for 13.48% of the total operating time. The research also involved monitoring of intensity pod cracking during the day depending on air temperature. Birdsfoot trefoil pod opening intensity increased of starts after 11 a.m. at air temperatures over 30 0 C when 80-90% of pods crack at 17- 20% moisture., U žetvi semena žutog zvezdana najveći problem predstavlja otvaranje mahuna pre i toku žetve. U punoj zrelosti mahune žutog zvezdana lako se otvaraju i seme se prosipa što dovodi do gubitaka. Problem otvaranja mahuna u značajnoj meri limitira uspešnu proizvodnju semena. Istraživani su eksplatacioni pokazatelji, kvalitet rada i pouzdanost starog univerzalnog žitnog kombajna 'Claas Mercator 50' u žetvi semena žutog zvezdana. Ispitivanje je obavljeno u poljskim uslovima Zapadne Sbije. Ustanovljeni su gubici na hederu i vršalici kombajna. Ukupni gubici hedera i vršalice na ispitivanom kombajnu iznosili su od 21,28% do 23,86% pri radnim brzinama 2,04 km/h i 2,63 km/h, što se moglo i očekivati za pomenuti kombajn i ovu kulturu u uslovima povećane vlažnosti useva. Tokom rada kombajna dolazilo je do zastoja tj. zagušenja vršidbene mase, usled povećane radna brzina, vlažnosti semena i slame. Utrošeno vreme za otklanjanje tehnoloških zastoja kod radne brzine od 2,63 km/h bilo je veće nego kod brzine od 2,04 km/h i iznosilo je 13,48% od ukupnog radnog vremena. Intenzitet pucanja u toku dana zavisno od temperature je takođe bio predmet ispitivanja ovog rada. Povećani intenzitet otvaranja mahuna počinje posle 11 sati, pri temperaturi vaduha preko 30 0 C kada se otvori 80-90% mahuna vlažnosti od 17- 20%.",
publisher = "Nacionalno naučno društvo za poljoprivrednu tehniku, Novi Sad",
journal = "Savremena poljoprivredna tehnika",
title = "Single phase harvest of birdsfoot trefoil seed by general-purpose combine harvesters, Jednofazna žetva semena žutog zvezdana univerzalnim žitnim kombajnom",
pages = "160-151",
number = "3",
volume = "40",
doi = "10.5937/SavPoljTeh1403151K"
}

Koprivica, R., Veljković, B., Turan, J., Pajić, M., Miodragović, R.,& Radojević, R.. (2014). Single phase harvest of birdsfoot trefoil seed by general-purpose combine harvesters. in Savremena poljoprivredna tehnika
Nacionalno naučno društvo za poljoprivrednu tehniku, Novi Sad., 40(3), 151-160.
https://doi.org/10.5937/SavPoljTeh1403151K

Koprivica R, Veljković B, Turan J, Pajić M, Miodragović R, Radojević R. Single phase harvest of birdsfoot trefoil seed by general-purpose combine harvesters. in Savremena poljoprivredna tehnika. 2014;40(3):151-160.
doi:10.5937/SavPoljTeh1403151K .

Koprivica, Ranko, Veljković, Biljana, Turan, Jan, Pajić, Miloš, Miodragović, Rajko, Radojević, Rade, "Single phase harvest of birdsfoot trefoil seed by general-purpose combine harvesters" in Savremena poljoprivredna tehnika, 40, no. 3 (2014):151-160,
https://doi.org/10.5937/SavPoljTeh1403151K . .