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

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

UTJECAJ FOLIJARNE APLIKACIJE Ca NA PRINOS I KVALITETU SLATKE PAPRIKE U STAKLENIČKIM 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 povrćarskoj proizvodnji kao što je i staklenička proizvodnja paprike. Dobra bioraspoloživost kalcija može se postići kalcizacijom, ali u mnogim slučajevima njena visoka cijena, višegodišnji efekti uz odloženo početno djelovanje te problemi koji nastaju radikalnom promjenom raspoloživosti drugih hraniva u tlu ograničavaju njenu primjenu. U ovom radu ispitivan je utjecaj folijarne primjene kalcija u obliku komercijalnog preparata "Calciogreen" kao dopuna standardne gnojidbe u stakleničkom uzgoju na prinos i kvalitet plodova paprike sorte Cecil na području istočne 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 2030°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 °C and 2030°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 2030°C compared to sand, but those differences were not statistically significant. When testing was done in germinator with 25°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 početna procena kvaliteta tek požnjevenog semena. Međunarod na pravila za ispitivanje semena propisuju alternativne metode za klijanje semena soje: pesak, između filter papira, na filter papiru uz prekrivanje peskom, i od 2020. godine organski supstrat. U Laboratoriji za ispitivanje semena, Instituta za kukuruz “Zemun Polje”, naklijavanje soje se vrši u pesku, na temperaturi 2030°C. Cilj ove studije bio je proceniti nekoliko dostupnih organskih supstrata i uporediti dobijene rezultate sa dosadašnjom laboratorijskom metodom. Pet partija soje različitog kvaliteta testirano je u četiri podloge za naklijavanje (3 organske i pe sak), pri dva temperaturna režima (25°C i 2030°C). Statistička analiza pokazala je da su sve organske podloge istog kvaliteta. Nešto veća klijavost u organskom supstratu u poređenju sa pes kom je ostvarena u eksperimentu na 2030°C, ali te razlike nisu bile statistički značajne. Pri likom ispitivanja u klijalištu sa 25°C pokazali su se pozitivni efekti organske podloge i ovaj uticaj je bio značajan, posebno za partije slabijeg kvaliteta. Nakon analize eksperimentalnih rezultata odlučeno je da se nastavi sa dosadašnjom laboratorijskom praksom naklijavanja u pesku i da se organska podloga koristi kao alternativni supstrat za ponovno ispitivanje partija semena sa nižim procentom klijavosti

Poređenje 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 (7.5°C for 10 days followed by 7 days at 20/30 °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 zemljišta itd.). Hladni test je važan metod za utvrđivanje vigora semena kukuruza. Iako je dobar pokazatelj nicanja u polju, i koristi se širom 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 različita 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 7,5°C, a zatim 7 dana na 20/30°C). Statističkom obradom podataka utvrđeno je da su se samooplodne linije značajno razlikovale po vigoru semena tj. tolerantnosti na niske temperature u periodu klijanja i početnog porasta. Sa druge strane nije utvrđena značajna razlika između dva primenjena supstrata u hladnom testu. Prosečna 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%), što se objašnjava variranjem u kvalitetu zemlje i prisustvu zemljišnih patogena. Obe ispitivane procedure su postigle visoku korelaciju sa nicanjem u polju. Rezultati ovih istraživanja ukazuju na mogućnost korišćenja peska kao supstrata u hladnom testu, čime bi se ispitivanje vigora semena kukuruza znatno olakšalo, 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 $\rho(\lambda)$ at large $|\lambda|$ is related to the behavior of the vertex degree distribution $P(k)$ at large $k$. In particular, as $P(k) \sim k^{-\gamma}$, $\rho(\lambda) \sim |\lambda|^{1-2\gamma}$. 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