40 research outputs found
Fuzzy model for predicting the number of deformed wheels
Deformation of the wheels damage cars and rails and affect on vehicle stability and safety. Repair and replacement cause high costs and lack of wagons. Planning of maintenance of wagons can not be done without estimates of the number of wheels that will be replaced due to wear and deformation in a given period of time. There are many influencing factors, the most important are: weather conditions, quality of materials, operating conditions, and distance between the two replacements. The fuzzy logic model uses the collected data as input variables to predict the output variable - number of deformed wheels for a certain type of vehicle in the defined period at a particular section of the railway
Digital Manufacturing as a basis for the development of the Industry 4.0 model
The digital manufacturing (DM) is base for Industry 4.0, that have following dimensions: (i) digital manufacturing based on advanced digital-oriented technologies, (ii) smart products (advanced production mode and new characteristics), and (iii) smart supply - chain (procurement of raw materials and delivery of finished products). Bidirectional exchange of information in collaborative production, using it exchange also for digital platforms of design of the innovative products. This paper presents developed model of Serbian digital factory with selected examples, specifically for the Manufacturing Execution System (MES) area
Digital Manufacturing as a basis for the development of the Industry 4.0 model
The digital manufacturing (DM) is base for Industry 4.0, that have following dimensions: (i) digital manufacturing based on advanced digital-oriented technologies, (ii) smart products (advanced production mode and new characteristics), and (iii) smart supply - chain (procurement of raw materials and delivery of finished products). Bidirectional exchange of information in collaborative production, using it exchange also for digital platforms of design of the innovative products. This paper presents developed model of Serbian digital factory with selected examples, specifically for the Manufacturing Execution System (MES) area
UTJECAJ FOLIJARNE APLIKACIJE Ca NA PRINOS I KVALITETU SLATKE PAPRIKE U STAKLENIÄKIM UVJETIMA
Calcium is an extremely important nutrient in highly productive fruit growing such as glasshousegrown sweet pepper. Good bioavailibility of calcium can be achieved by calcisation, but in many cases owing to its high prices, long-term effects, along with a delayed initial effect, as well as problems that appear due to radical change in
availability of other nutrients in soil, its application is restricted. This paper deals with research on effects of foliar applications of the commercial chemical named "Calciogreen", as a supplement to the standard fertilization in greenhouse growing, on yield and quality of pepper fruits of the Cecil cultivar in the region of East Croatia.Kalcij je izrazito važan nutrijent u visokoproduktivnoj povrÄarskoj proizvodnji kao Å”to je i stakleniÄka proizvodnja paprike. Dobra bioraspoloživost kalcija može se postiÄi kalcizacijom, ali u mnogim sluÄajevima njena visoka cijena, viÅ”egodiÅ”nji efekti uz odloženo poÄetno djelovanje te problemi koji nastaju radikalnom promjenom raspoloživosti drugih hraniva u tlu ograniÄavaju njenu primjenu. U ovom radu ispitivan je utjecaj folijarne primjene kalcija u obliku komercijalnog preparata "Calciogreen" kao dopuna standardne gnojidbe u stakleniÄkom uzgoju na prinos i kvalitet plodova paprike sorte Cecil na podruÄju istoÄne Hrvatske
Rail inspection of RCF defects
Rail defects due to rolling contact fatigue (RCF) threaten the traffic safety around the world. That hazard is more distinct on railways without adequate maintenance strategy. Realization of interoperability of European railway network demands from every infrastructure manager to have a maintenance plan for the infrastructure subsystem. Besides that, this plan includes rail inspection and strategy against RCF defects. This paper emphasizes the importance of rail inspection and early detection of RCF because the most of RCF crack should be removed in rail grinding campaigns (preventive, cyclical and corrective activities) during the whole rail service life
Eksperimentalna procena organskih podloga za ispitivanje klijavosti semena soje
High germination of seeds and seedling establishment are critical for soybean production
since it determines crop density and eventually affects the yield. Accurate evaluation of the ger mination potential of sowing material is valuable, as well as initial quality assessment of newly
harvested seed. ISTA Rules prescribe alternative methods for soybean seed germination: sand,
between paper, top of paper covered with sand and since 2020 organic growing media. In the
Seed Testing Laboratory at the Maize Research Institute soybean germination is conducted in the
sand at 2030Ā°C. The objective of this study was to evaluate several available organic growing
media and compare results obtained with the standard laboratory method. Five soybean seed lots
of different quality were tested in four germination growing media (3 organic and sand), at two
temperature regimes (25 Ā°C and 2030Ā°C). Statistical analyses showed that all types of organic
growing media were of the same quality. Slightly higher germination in organic growing media
was obtained in the experiment at 2030Ā°C compared to sand, but those differences were not
statistically significant. When testing was done in germinator with 25Ā°C positive effects of organic
growing media were identified and this impact was significant, especially for low-quality seed
lots. The experimental outcome was to continue with routine practice and use organic growing
media for retesting of seed lots with lower germination as an alternative substrate.
Key words: germination, organic substrate, sand, soybean, temperatureVisoka klijavost semena i uniforman rast klijanaca su presudni za proizvodnju soje, jer od
toga zavisi gustina useva i na kraju, prinos. Precizna procena potencijala klijavosti setvenog ma terijala je izuzetno važna, kao i poÄetna procena kvaliteta tek požnjevenog semena. MeÄunarod na pravila za ispitivanje semena propisuju alternativne metode za klijanje semena soje: pesak,
izmeÄu filter papira, na filter papiru uz prekrivanje peskom, i od 2020. godine organski supstrat.
U Laboratoriji za ispitivanje semena, Instituta za kukuruz āZemun Poljeā, naklijavanje soje se
vrÅ”i u pesku, na temperaturi 2030Ā°C. Cilj ove studije bio je proceniti nekoliko dostupnih
organskih supstrata i uporediti dobijene rezultate sa dosadaŔnjom laboratorijskom metodom.
Pet partija soje razliÄitog kvaliteta testirano je u Äetiri podloge za naklijavanje (3 organske i pe sak), pri dva temperaturna režima (25Ā°C i 2030Ā°C). StatistiÄka analiza pokazala je da su sve
organske podloge istog kvaliteta. NeÅ”to vecĢa klijavost u organskom supstratu u poreÄenju sa pes kom je ostvarena u eksperimentu na 2030Ā°C, ali te razlike nisu bile statistiÄki znaÄajne. Pri likom ispitivanja u klijaliÅ”tu sa 25Ā°C pokazali su se pozitivni efekti organske podloge i ovaj uticaj
je bio znaÄajan, posebno za partije slabijeg kvaliteta. Nakon analize eksperimentalnih rezultata
odluÄeno je da se nastavi sa dosadaÅ”njom laboratorijskom praksom naklijavanja u pesku i da se
organska podloga koristi kao alternativni supstrat za ponovno ispitivanje partija semena sa nižim
procentom klijavosti
PoreÄenje dve procedure hladnog testa za ispitivanje vigora semena samooplodnih linija kukuruza
Cold test (CT) is a valuable method of assessing maize seed vigour. Although widely used CT is not standardized because of variations in CT procedures. The objective of this study was to evaluate seed vigour of 15 maize inbred lines developed at the Maize Research Institute Zemun Polje, using two different substrates (soil and sand) in a severe CT (7.5Ā°C for 10 days followed by 7 days at 20/30 Ā°C). Statistical analysis showed that inbred lines differ significantly in seed vigour, and no difference between two applied substrates in CT. Coefficients of variation were lower in CT with sand (6.05 %), compared to the CT with soil (6.74%) due to variation in soil quality and presence of soil-borne pathogens. Both CT procedures were highly correlated with field emergence. Results of this research indicate that CT with sand is appropriate for testing maize seed vigour, with the potential for standardization.Vigor semena je veoma važan parametar kvaliteta, jer ukazuje na sposobnost semena da klija u suboptimalnim uslovima (niska temperatura, visoka vlažnost zemljiÅ”ta itd.). Hladni test je važan metod za utvrÄivanje vigora semena kukuruza. Iako je dobar pokazatelj nicanja u polju, i koristi se Å”irom sveta, hladni test nije standardizovan zbog razlika u proceduri (temperatura, vrsta i vlažnost supstrata). Cilj ovog rada bio je ispitivanje vigora semena samooplodnih linija kukuruza primenom dva razliÄita supstrata (zemlja i pesak) u hladnom testu. Za ispitivanje je odabrano 15 samooplodnih linija kukuruza stvorenih u Institutu za kukuruz 'Zemun Polje'. Primenjeni su izrazito stresni uslovi ispitivanja u hladnom testu (10 dana na 7,5Ā°C, a zatim 7 dana na 20/30Ā°C). StatistiÄkom obradom podataka utvrÄeno je da su se samooplodne linije znaÄajno razlikovale po vigoru semena tj. tolerantnosti na niske temperature u periodu klijanja i poÄetnog porasta. Sa druge strane nije utvrÄena znaÄajna razlika izmeÄu dva primenjena supstrata u hladnom testu. ProseÄna klijavost 15 samooplodnih linija u hladnom testu sa peskom iznosila je 82,2%, a u hladnom testu sa zemljom 80,1%. Koeficijent varijacije je bio niži u hladnom testu sa peskom (6,05%), nego u hladnom testu sa zemljom (6,74%), Å”to se objaÅ”njava variranjem u kvalitetu zemlje i prisustvu zemljiÅ”nih patogena. Obe ispitivane procedure su postigle visoku korelaciju sa nicanjem u polju. Rezultati ovih istraživanja ukazuju na moguÄnost koriÅ”Äenja peska kao supstrata u hladnom testu, Äime bi se ispitivanje vigora semena kukuruza znatno olakÅ”alo, a ujedno bi se stekli uslovi za standardizaciju hladnog testa
Management of roe deer population (Capreolus capreolus L.) in Serbia
ABSTRACT The research was conducted during the 2018/19 hunting year at three hunting grounds: "Barajevska reka" - "Takovo" and "Jadar". The average density of Roe deer in hunting grounds varied from 48.67 to 74 individuals per 1,000 ha of hunting-productive area. However, when observing the number of individuals per 1,000 ha of total hunting area, the density varies from 16.07 individuals to 34.72 individuals. The determined gender ratio at the hunting ground "Jadar" was (M: F = 1: 0.93). At the hunting ground "Takovo", the gender ratio was (M: F = 1: 1.22), while at the hunting ground "Barajevska reka" the ratio was (M: F = 1: 1.59). The average fertility of Roe deer was 1.67 embryos per individual, or 1.75 embryos per pregnant female. Depending on the study area, the real growth varied from 0.54 to 0.73 fawns per female. Loss in Roe deer are caused mostly by biotic factors. The determined average age of shot individuals varied depending on the hunting ground from 3.53 to 5.24 years. The current state of Roe deer populations in Serbia varies between analyzed hunting grounds, but the overall situation is quite unsatisfactory, especially in terms of density, gender ratio and age structure of culled individuals
Spectra of complex networks
We propose a general approach to the description of spectra of complex
networks. For the spectra of networks with uncorrelated vertices (and a local
tree-like structure), exact equations are derived. These equations are
generalized to the case of networks with correlations between neighboring
vertices. The tail of the density of eigenvalues at large
is related to the behavior of the vertex degree distribution
at large . In particular, as , . We propose a simple approximation, which enables us to
calculate spectra of various graphs analytically. We analyse spectra of various
complex networks and discuss the role of vertices of low degree. We show that
spectra of locally tree-like random graphs may serve as a starting point in the
analysis of spectral properties of real-world networks, e.g., of the Internet.Comment: 10 pages, 4 figure