Greške na bešavnim cijevima

Defects on seamless tubes ocurring in the sequence of technological process of the production of steel charge and seamless tubes beginning with classically cast charge (which dominantely caused participating of defects), continuously cast charge and up-to-date steel production (which causes an irrelevant amount of defects) are systemized. Separately and in detail, main tube rolling defects in pilger rolling mill are described.U radu su sistematizirane greške na bešavnim cijevima slijedom faza tehnološkog procesa proizvodnje čeličnog uloška i bešavnih cijevi počev od klasično lijevanog uloška, (uzrokovao dominantno učešće grešaka) kontinuirano lijevanog uloška i suvremene proizvodnje čelika (zanemarivo uzrokuje greške na bešavnim cijevima). Posebno i detaljno su opisane glavne valjačke greške na cijevima u pilger valjaonici

Broomrape seed germination on nutritive media and possibility of its biological control

In tests of sunflower hybrids' susceptibility to broomrape under artificial inoculation conditions, a high germination rate of broomrape seed used for infestation is prerequisite. On the other hand, one of the ways to reduce the great potential of broomrape seeds is biological control. Seed germination was evaluated on three different media. The first medium was water agar with giberellic acid (GA3) and presence of roots of the susceptible sunflower hybrid NS-H-111. The medium for the evaluation of influence of the biological agent on seed germination was the same with bioagent Trifender added in concentration of 1%. The check was a medium with GA3 only. Seeds of Orobanche cumana were collected in sunflower fields in Vojvodina at five different localities. The seeds were placed in Petri dishes with nutritive media and incubated at 25°C in the dark. Germination rate, germ length and distance of germinated broomrape seed from sunflower root were determined at 7 day intervals under the dissecting microscope. After 28 days on the GA3 medium with sunflower roots broomrape seeds germinated at the rate of 44-68%, while on media with Trifender they had significantly lower germination (4-41%). There was no broomrape seed germination on water agar with GA3 only in any sample. Germ lengths of seeds on the GA3+sunflower roots media were significantly longer than those on the medium with Trifender. Orobanche seed which were closer to the sunflower root had better germination on both media

Influence of nutritive media and low temperatures on broomrape seed germination

The germination of broomrape seeds on different nutritive media and at low temperatures was tested. Broomrape seed was collected from three localities in Northern part of Serbia. Nutritive media which were used are: water agar, water agar with gibberelic acid and water agar with biological agent Trifender. Temperature regimes were: without cooling, and in the fridge for 7, 14 and 21 days at + 4°C. The highest number of germinated seeds was observed on the agar medium with gibberelic acid in presence of sunflower roots. Cooling of broomrape seeds on 4°C during 21 day leads to stimulation of their germination and average radicle length. The effect of bio-agent Trifender should be further investigated

Phoma Macdonaldi na semenu i njen značaj u etiologiji crne pegavosti suncokreta

Phoma macdonaldi Boerema, teleomorph Leptosphaeria lindquistii Frezzi, is a widespread pathogen of sunflower. The aim of this research was to identify the presence of fungus P. macdonaldi in seed of different sunflower hybrids, as well as the correlation between seed and field infection. Phoma black stem assessment was performed on three hybrids grown in six localities in Serbia. Untreated and processed seeds of these hybrids were used in the seed health test. Severity of the disease did not differ between localities. Average disease index for hybrids H7, H9 and H19 was 14.01%, 13.25% and 11.83% respectively, and it shows that there are no significant differences in hybrid susceptibility. The index of disease indicates tolerance of these hybrids to Phoma black stem. Seed analysis showed the presence of fungi from the following genera: Phoma, Alternaria, Botrytis, Sclerotinia, Penicillium and Aspergillus. Seed infection with Phoma (of the untreated seeds) per hybrid ranged from 1.2–3.5%. There is no significant correlation between stem and seed infection.Phoma macdonaldi Boerema; teleomorf Leptosphaeria lindquistii Frezzi jedan je od najraširenijih patogena suncokreta. Cilj ovog istraživanja bio je da se utvrdi prisustvo gljive P. macdonaldi na semenu različitih hibrida suncokreta kao i korelacija između infekcije stabla u polju i infekcije semena. Procena inteziteta bolesti izvršena je na tri hibrida koja su gajena na šest lokaliteta. Za određivanje zdravstvenog stanja korišćeno je netretirano i dorađeno seme hibrida ispitivanih u polju. Intenzitet napada bolesti nije se značajno razlikovao među lokalitetima. Prosečan indeks oboljenja za hibride H7, H9 i H19 bio je 14,01%, 13,25% i 11,83% što pokazuje da ne postoje značajne razlike u osetljivosti hibrida prema crnoj pegavosti. Takođe, dobijeni indeks ukazuje na tolerantnost ispitivanih hibrida prema ovom prouzrokovaču bolesti. Analizom zdravstvenog stanja semena suncokreta utvrđeno je prisustvo gljiva iz sledećih rodova: Phoma, Alternaria, Botrytis, Sclerotinia, Penicillium i Aspergillus. Zaraženost semena gljivom P. macdonaldi utvrđena je na dorađenom i netretiranom semenu i kretala se od 1,2–3,5%. Nije utvrđena statistički značajna korelacija između infekcije stabla i semena u poljskim uslovima. Ovo se može objasniti niskim stepenom napada patogena i prisustvom simptoma samo na stablu, a ne na glavici suncokreta

Effects of long-term fertilization on yield of siderates and organic matter content of soil in the process of recultivation

The aim of this research was to determine the possibility of increasing organic matter content in humusless deposol topsoil and forming of a more favourable adsorptive complex by introducing green manure. Green manure biomass came from these compound plant species: winter rye + common vetch, forage pea + rapeseed mustard and Sudan grass. Compound feed was sown on degraded soil (type deposol) of the Stanari coal mine. Applied cultivation practices included primary and secondary tillage and additional plant nutrition. Mineral fertilizers were applied: NPK 7:20:30 (400 kg ha(-1)) and CAN 27% (200 kg ha(-1)). One of the treatments included addition of bentonite clay as absorbent of nutrients. During intensive vegetation the growth of the green biomass was measured, the crops were harvested, cut and ploughed in deposol topsoil. Organic matter content in deposol was determined when soil samples were taken 6 months after green manure incorporation. The results show that the mineral fertilization of siderates significantly increased green biomass yield and Sudan grass gave two cuts, which positively affected the increase of organic matter content in soil

Razvoj sposobnosti atomsko-biološko-hemijske službe u odgovoru na pretnje hemijskim oružjem

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Germination of broomrape seed on different nutritive media

In the agroecological conditions of Serbia broomrape (Orobanche cumana) as a parasite of sunflower has been appearing with varying intensity almost every year and can cause significant damage. Resistant or tolerant sunflower hybrids are the most efficient and the most economical measures in the suppression of this parasitic plant. In the tests of sunflower hybrids susceptibility to broomrape under artificial infestation, high germinativity of broomrape seeds used for infestation. The aim of this paper is to evaluate influence of different nutritive media on broomrape seed germination including water agar (WA), water agar+giberellic acid (GA cone. 25 ppm) and water agar+trifender (T conc.1%) in the presence or not of 7days old sunflower roots, hybrid (NS-H-111). Trifender is a biological pesticide from Trichoderma asperellum acting as plant growth promoter with beneficial side effect to control soil borne pathogens when incorporated in soil. Seeds of Orobanche cumana were collected in the sunflower fields in Vojvodina (Senta and Vrsac) during 2009. Seed samples were kept in the fridge on 4°C for 10 months for break dormancy. Surface sterilized seeds (25 seeds in 4 replicates for each treatment) were put in Petri dishes with nutritive media with or without roots of 7 day-old sunflower plants and incubated at 25°C in the dark. Germination rate was determined every 7 days under dissecting microscope. Data were analyzed by ANOVA and Duncan test

Empirical Models for Dark Matter Halos. III. The Kormendy relation and the log(rho_e)-log(R_e) relation

We have recently shown that the 3-parameter density-profile model from Prugniel & Simien provides a better fit to simulated, galaxy- and cluster-sized, dark matter halos than an NFW-like model with arbitrary inner profile slope gamma (Paper I). By construction, the parameters of the Prugniel-Simien model equate to those of the Sersic R^{1/n} function fitted to the projected distribution. Using the Prugniel-Simien model, we are therefore able to show that the location of simulated (10^{12} M_sun) galaxy-sized dark matter halos in the _e-log(R_e) diagram coincides with that of brightest cluster galaxies, i.e., the dark matter halos appear consistent with the Kormendy relation defined by luminous elliptical galaxies. These objects are also seen to define the new, and equally strong, relation log(rho_e) = 0.5 - 2.5log(R_e), in which rho_e is the internal density at r=R_e. Simulated (10^{14.5} M_sun) cluster-sized dark matter halos and the gas component of real galaxy clusters follow the relation log(rho_e) = 2.5[1 - log(R_e)]. Given the shapes of the various density profiles, we are able to conclude that while dwarf elliptical galaxies and galaxy clusters can have dark matter halos with effective radii of comparable size to the effective radii of their baryonic component, luminous elliptical galaxies can not. For increasingly large elliptical galaxies, with increasingly large profile shapes `n', to be dark matter dominated at large radii requires dark matter halos with increasingly large effective radii compared to the effective radii of their stellar component.Comment: AJ, in press. (Paper I can be found at astro-ph/0509417

Impact of non-protein nitrogen substances on grape pomace silage quality

In this study grape pomace was ensilaged without and with the addition of NPN substances (Benural) at the dose of 0.5, 1.0 and 1.5% of the amount of husk and with the addition of inoculant based on homo and hetero fermentative lactic acid bacteria. The greatest effect on the nutritional value had application of Benural, especially in increasing the CP content from 126.9 to 178.3 g kg-1DM, an increase of over 40%. Application of Benural increased the ammonia and soluble nitrogen several times, but even with the maximum addition of Benural percentage of ammonia nitrogen in the total nitrogen reached only slightly above 5% NH3 -N/Σ N (5.38%), while the percentage of soluble nitrogen in total nitrogen was 28.29%. The application of inoculants generally had no significant impact, both on the chemical composition and the fermentation process

Probing the Wave Nature of Light-Matter Interaction

The wave-particle duality of light is a controversial topic in modern physics. In this context, this work highlights the ability of the wave-nature of light on its own to account for the conservation of energy in light-matter interaction. Two simple fundamental properties of light as wave are involved: its period and its power P. The power P depends only on the amplitude of the wave’s electric and magnetic fields (Poynting’s vector), and can easily be measured with a power sensor for visible and infrared lasers. The advantage of such a wave-based approach is that it unveils unexpected effects of light’s power P capable of explaining numerous results published in current scientific literature, of correlating phenomena otherwise considered as disjointed, and of making predictions on ways to employ the electromagnetic (EM) waves which so far are unexplored. In this framework, this work focuses on determining the magnitude of the time interval that, coupled with light’s power P, establishes the energy conserved in the exchange of energy between light and matter. To reach this goal, capacitors were excited with visible and IR lasers at variable average power P. As the result of combining experimental measurements and simulations based on the law of conservation of energy, it was found that the product of the period of the light by its power P fixes the magnitude of the energy conserved in light’s interaction with the capacitors. This finding highlights that the energy exchanged is defined in the time interval equal to the period of the light’s wave. The validity of the finding is shown to hold in light’s interaction with matter in general, e.g. in the photoelectric effect with x-rays, in the transfer of electrons between energy levels in semiconducting interfaces of field effect transistors, in the activation of photosynthetic reactions, and in the generation of action potentials in retinal ganglion cells to enable vision in vertebrates. Finally, the validity of the finding is investigated in the low frequency spectrum of the EM waves by exploring possible consequences in microwave technology, and in harvesting through capacitors the radio waves dispersed in the environment after being used in telecommunications as a source of usable electricity