Uticaj podloge na klijavost tretiranog semena suncokreta

Results of the examination of Rimi hybrid seed showed the existence of a highly significant effect of different substratum on germination energy and germination. Also, a highly significant influence was detected between treatments, while the substratum x treatments interaction was significant. On average, germination energy was the highest on filter paper and it was 90.10%. Also, the germination was the best on filter paper (92.05%). This value was statistically significantly higher (by 13.60%) with respect to germination determined in sand and by 4.00% concerning germination determined in compost.Rezultati ispitivanja energije klijanja i klijavosti semena hibrida Rimi na različitim podlogama za ispitivanje klijavosti ukazali su na postojanje visoko značajnog uticaja podloge na energiju klijanja i klijavost semena. Takođe, visoko značajna razlika utvrđena je i kod primenjenih tretmana, dok se značajna razlika ispoljila kod interakcije podloga x tretmani. U proseku, energija klijanja bila je najveća kod semena koje je naklijavano na filter papiru i iznosila je 90,10%. Ispitivanje klijavosti semena pokazalo je u proseku, takođe, najveću vrednost kod naklijavanja na filter papiru (92,05%). Ova vrednost bila je statistički visoko značajna u odnosu na rezultat ispitivanja u pesku za 13,60%, a u odnosu na ispitivanje u kompostu za 4,00%

Photoluminescent and Photocatalytic Properties of Eu3+-Doped MgAl Oxide Coatings Formed by Plasma Electrolytic Oxidation of AZ31 Magnesium Alloy

The synthesis of Eu3+-doped MgAl oxide coatings containing MgO and MgAl2O4 was accomplished through plasma electrolytic oxidation of AZ31 magnesium alloy in aluminate electrolyte with the addition of Eu2O3 particles in various concentrations. Their morphological, structural, and above all, photoluminescent (PL) and photocatalytic activity (PA) were thoroughly investigated. PL emission spectra of MgAl oxide coatings feature characteristic emission peaks, which are ascribed to f–f transitions of Eu3+ ions from excited level 5D0 to lower levels 7FJ. The charge transfer state of Eu3+ or direct excitation of the Eu3+ ground state 7F0 into higher levels of the 4f-manifold are both attributed to the PL peaks that appear in the excitation PL spectra of the obtained coatings. The fact that the transition 5D0 → 7F2 (electrical dipole transition) in Eu3+-doped MgAl oxide coatings is considerably stronger than the transition 5D0 → 7F1 (magnetic dipole transition) indicates that Eu3+ ions occupied sites with non-inversion symmetry. Because of oxygen vacancy formation, the Eu3+-doped MgAl oxide coatings had a higher PA in the degradation of methyl orange than the pure MgAl oxide coating. The highest PA was found in Eu3+-doped MgAl oxide coating formed in an aluminate electrolyte with 4 g/L of Eu2O3 particles. The PA, morphology, and phase of Eu3+-doped MgAl oxide coatings did not change after several consecutive runs, indicating outstanding stability of these photocatalysts

Relationship between marine epilithic diatoms and environmental variables in oligotrophic bay, NE Mediterranean

The taxonomic composition and structure of a marine epilithic diatom community were sampled from the bottom of the two sites at monthly intervals from January to December 2011 in the small semi-enclosed oligotrophic Neum Bay in Bosnia and Herzegovina (Middle Adriatic). Altogether, 264 diatom taxa (species and infraspecific taxa) within 69 genera were identified. Among them, 149 and 203 taxa occurred in samples from the shallow (0.5 m depth) and deep (8 m depth) sites, respectively. The monthly distribution of most of the diatoms was irregular and high numbers of sporadic taxa were found. SIMPER analysis indicated that the difference between shallow and deep sites could be largely attributed to the frequently recorded diatom taxa and those with high percentage abundances. They were Halamphora coffeiformis, Caloneis excentrica, Cocconeis scutellum var. scutellum, Licmophora flabellata, Licmophora gracilis, Licmophora sp., Navicula abunda, Rhabdonema adriaticum, and Striatella unipunctata. Canonical Correspondence Analysis (CCA) showed that temperature, oxygen saturation (O2/O2′), silicate concentration (SiO4), and salinity were the most important factors influencing diatom community structure in the bay

Certain classes of polygons in R^2 and areas of polygons

In this article we consider certain classes of polygons in R^2 and areas of polygons

Application of Micro-Arc Discharges during Anodization of Tantalum for Synthesis of Photocatalytic Active Ta2O5 Coatings

Ta2O5 coatings were created using micro-arc discharges (MDs) during anodization on a tantalum substrate in a sodium phosphate electrolyte (10 g/L Na3PO4·10H2O). During the process, the size of MDs increases while the number of MDs decreases. The elements and their ionization states present in MDs were identified using optical emission spectroscopy. The hydrogen Balmer line Hβ shape analysis revealed the presence of two types of MDs, with estimated electron number densities of around 1.1 × 1021 m−3 and 7.3 × 1021 m−3. The effect of MDs duration on surface morphology, phase and chemical composition, optical absorption, and photoluminescent, properties of Ta2O5 coatings, as well as their applications in photocatalytic degradation of methyl orange, were investigated. The created coatings were crystalline and were primarily composed of Ta2O5 orthorhombic phase. Since Ta2O5 coatings feature strong absorption in the ultraviolet light region below 320 nm, their photocatalytic activity is very high and increases with the time of the MDs process. This was associated with an increase of oxygen vacancy defects in coatings formed during the MDs, which was confirmed by photoluminescent measurements. The photocatalytic activity after 8 h of irradiation was around 69%, 74%, 80%, and 88% for Ta2O5 coatings created after 3 min, 5 min, 10 min, and 15 min, respectively

ZnO Particles Modified MgAl Coatings with Improved Photocatalytic Activity Formed by Plasma Electrolytic Oxidation of AZ31 Magnesium Alloy in Aluminate Electrolyte

MgAl and MgAl/ZnO coatings were prepared by plasma electrolytic oxidation (PEO) of AZ31 magnesium alloy in aluminate electrolyte (5 g/L NaAlO2) without and with addition of ZnO particles in various concentrations. The MgAl coating was partially crystallized and contained MgO and MgAl2O4 phases. The addition of ZnO particles to aluminate electrolyte had no significant effect on the surface morphology of formed coatings, while the Zn content increased with ZnO particle concentrations. X-ray diffraction confirmed the incorporation of ZnO particles in the coatings. The photodegradation of methyl orange (10 cm3 of 8 mg/L) was used to measure the photocatalytic activity (PA) of MgAl and MgAl/ZnO coatings. The PA of MgAl coating after 8 h of irradiation was around 58%, while the PA of MgAl/ZnO coatings formed in aluminate electrolyte with the addition of ZnO particles in concentrations of 4 g/L, 8 g/L, and 12 g/L were around 69%, 86%, and 97%, respectively

Pouzdanost složenih vodovodnih sistema na primeru RVS Dubovac-Zrenjanin-Kikinda

Water supply networks have a specific feature that makes them more complicated then many other water management systems. Namely, to make sure that the system performs well, apart from the mechanical characteristics of the system, the hydraulic reliability of its components must also be verified. In this particular case the reliability of the regional water supply system Dubovac-Zrenjanin-Kikinda has been assessed, the system being based on the concept of centralized water supply, in which water is conducted from the different regional sources to the municipal centers, and then distributed to the users.Vodovodni (distributivni) sistemi imaju jednu specifičnost koja ih, sa gledišta pouzdanosti, čini složenijim od drugih sistema. Da bi sistem uspešno obavljao svoju funkciju pored pouzdanosti mehaničkih karakteristika sistema uzima se u obzir i pouzdanost hidrauličkih parametara sistema. U ovom radu se na primeru regionalnog vodovodnog sistema Dubovac-Zrenjanin-Kikinda koji se bazira na konceptu centralizovanog vodosnabdevanja dovođenjem vode sa regionalnog izvorišta, preko PPV i dalje regionalnim cevovodima distribuira do opštinskih centara razmatra problem određivanja pouzdanosti vodovodnog sistema

Variability of head diameter in sunflower hybrids depending on planting date

Head size contributes substantially to seed yield of sunflower because it influences both number of seeds per head, and seed size. The aim of this field study was to determine the variability of head diameter in sunflower hybrids depending on planting date across three cropping seasons. Three hybrids (Miro, Rimi, Pobednik) were sown at four planting dates (PD1 - 20th of March, PD2 - 10th of April, PD3 - 30th of April, PD4 - 20th of May). Head diameter was analysed in the stage of flowering and physiological maturity. The trial was arranged as Randomized Complete Block Design (RCBD) with four replications. Analysis of variance (ANOVA) showed that the effect of year, hybrid, planting date and most interactions were highly significant for head diameter in the flowering stage. In the stage of physiological maturity head diameter varied significantly depending only on the planting date. Also, all interactions, except year x hybrid (Y x H), were highly significant. Planting date had significant influence on head diameter in the stage of flowering and physiological maturity in sunflower. With later sowing head diameter increased, so that significantly highest head diameter across planting dates was found in PD4 (11.8 cm in flowering stage, and 22.6 cm at the stage of physiological maturity). Study results may be helpful in the recommendation for optimal planting date in sunflower