Effects of harvesting dates and plant population on sugar beet seed fractions

The effects of harvest date and plant population on sugar beet seed size by fraction were studied in a three-year field trial after primary seed cleaning. The seed size was highly significantly affected by the different harvesting dates. The highest percentage of the seeds fell into either the 3.5-4.5 mm fraction or the 4.5-6.0 mm one. This indicates that in the three different climatic years the highest amount of large seeds was obtained with hybrids tolerant of sugar beet rhizomania. In most cases, no significant differences were found when comparing the different plant populations per hectare. Highly significant differences were found among the study years resulting from the influence of uncontrolled climatic factors of the agroecological region. This leads to the conclusion that seed sugar beet harvesting is the most important cultural practice affecting seed size in this crop during the production process

Influence of PEO molecular weight on properties of ZnO/PEO composites

The removal of inorganic, organic and biological pollutants from drinking water and wastewater is one of the key steps in environmental protection. In recent 10 years a heterogeneous photocatalysis, as an efficient method for the degradation and mineralization of pollutants from water, has been widely studied and developed. For heterogeneous photocatalysis mostly used materials to initiate the photoreaction are oxide semiconductors such as TiO2 and ZnO. However, these oxide semiconductors, having band gap energies around 3.3 eV, can absorb UV light only. Since sunlight is a source of clean and cheap energy, where UV light makes no more than 3–5% of the total sunlight, it is highly desirable to modify the oxide semiconductor materials to be capable for visible light photocatalysts. Numerous approaches have been applied to modify the optical absorption properties and to improve the visible light photocatalytic activity including: (1) the incorporation of transition metal ions into the crystal structure, (2) sensitization of the particles’ surface, (3) hydrogenation, (4) the incorporation of crystalline defects in metal oxide semiconductors in the form of vacancies and interstitials, etc. Microwave processing is recognized as an attractive synthesis technique to introduce lattice defects. In this study ZnO spheroidal nanoparticles, synthesized by microwave processing, were used for preparation of composites with polyethylene oxide (PEO). The phase purity and crystal structure of the composites were investigated by X-ray diffraction (XRD) and Raman spectroscopy. The composites' particles morphology and size distributions were studied by FE–SEM and laser diffraction particle size analyzer, respectively. The optical properties were studied using UV–Vis diffuse reflectance and photoluminescence spectroscopy. It is found that ZnO and ZnO/PEO composites absorb about 50% of visible light, also red-shift of band gap energy (0.12-0.15 eV) compared to bulk ZnO was determined. The effect of PEO molecular weights, 200.000, 600.000 and 900.000 g/mol, on photocatalytic activity of ZnO/PEO composites were examined via degradation of methylene blue (MB) under direct sunlight irradiation. A large efficiency of MB degradation was found after 6 h of irradiation. The enhanced photocatalytic activity of ZnO/PEO composites is attributed to the: (1) lattice defects introduced in ZnO crystal structure by rapid microwave processing, and (2) presence of PEO as a source of oxygen interstitials. In order to confirm and further clarify the experimental results ab initio calculations based on density functional theory (DFT) were performed

Crystal structure, optical and magnetic properties of Zn1-xFeyO(1-x+1.5y) (0.06 ≤ y/(1-x) ≤ 0.27) nanoparticles

Brza i ekološki prihvatljiva sinteza uzoraka mikrotalasnim procesiranjem korišćena je za pripremu ZnO nanočestica dopiranih sa 5, 10, 15 i 20 atomskih procenata (at. %) Fe (Zn1-xFeyO(1-x+1.5y)). Fazni sastav, kristalna struktura, širina energetskog procepa, morfologija, hemija površine, optička i magnetna svojstva ispitani su kako bi se utvrdio uticaj supstitucije jona Zn2+ jonima Fe3+ na svojstva čistog ZnO. Korišćene metode ispitivanja su: rendgenska difrakcija na prahu, infracrvena spektroskopija sa Furijeovom transformacijom, optička emisiona spektroskopija sa induktivno spregnutom plazmom, ramanska i Mesbauerova spektroskopija, rendgenska fotoelektronska spektroskopija, skenirajuća i transmisiona elektronska mikroskopija, BET (Brunauer-Emmett-Teller) metoda, UV-Vis difuzna refleksiona spektroskopija, fotoluminiscentna spektroskopija, elektronska paramagnetna rezonancija. U sintetisanim uzorcima, at. % Fe bio je u skladu sa predviđenim pre sinteze i potvrđeno je oksidaciono stanje jona Fe3+. Svi uzorci imaju heksagonalnu vurcitnu strukturu. Mala količina faze spinela ZnFe2O4 javlja se kod uzorka sa 20 at. % Fe. Zamenom jona Zn2+ jonima Fe3+ promenjeno je lokalno uređenje i narušena simetrija kristalne rešetke ZnO. Čestice prahova Zn1-xFeyO(1-x+1.5y) su sferoidne, u prahu ZnO sa 5 at. % Fe postoji mali udeo pločastih čestica. Raspodela Fe u ZnO prahu je homogena. Svi uzorci su na sobnoj temperaturi paramagnetni. Provodljivost uzoraka na sobnoj temperaturi raste sa povećanjem at. % Fe. Linearna voltametrija pokazala je bolju katalitičku aktivnost uzorka sa 5 at. % Fe za RRK u poređenju sa čistim ZnO. Uzorak sa 10 at. % Fe pokazao se kao obećavajući bifunkcionalni katalizator za RRK/RIK. Fotokatalitička aktivnost raste sa povećanjem at. % Fe u sastavu rešetke.Eco-friendly and rapid microwave processing of a precipitate was used to produce Fe-doped ZnO nanoparticles with 5, 10, 15 and 20 at. % of Fe (Zn1-xFeyO(1-x+1.5y)). The phase composition, crystal and band structure, morphology, textural properties, surface chemistry, optical and magnetic properties were examined to comprehend the influence of Fe3+ to Zn2+ substitution on the characteristics and catalytic activity of ZnO paticles. The analysing methods were: X-ray diffraction, Fourier transform infrared spectroscopy, inductively coupled plasma optical emission spectrometry, Raman, Mössbauer and X-ray photoelectron spectroscopy, electron paramagnetic resonance spectroscopy, scanning electron microscopy, transmission electron microscopy, the Brunauer-Emmett-Teller (BET) method, diffuse reflectance spectroscopy and photoluminescence spectroscopy. Atomic % of Fe in the Zn1-xFeyO(1-x+1.5y) were in accordance with planned and oxidation state of Fe3+ was confirmed. Samples had hexagonal wurtzite structure. Small amount of the ZnFe2O4 spinel phase occurs in sample with 20 at. % Fe. Partial Fe3+ to Zn2+ substitution has significantly altered local ordering in ZnO distressing the lattice symmetry. All powders consists spheroidal particles. Small amount of plate like particles exists in 5 at. % Fe sample. Fe atoms have homogenous distribution throughout ZnO matrix. At room temperature all the samples are paramagnetic. The conductivity of samples at room temperature increases with increasing at. % Fe. Linear sweep voltammetry showed an improved catalytic activity of 5 at. % Fe sample toward ORR, compared to pure ZnO. Sample with 10 at. % of Fe could be a promising bifunctional catalyst for OER/ORR. Photocatalityc activity increased with increasing of the at % of Fe in ZnO lattice

Lithium-ion insertion into anatase TiO2 nanotube arrays at room temperature

High demand for efficient storage devices has set a goal of improving the efficiency of lithium-ion batteries (LIBs), which currently represent the most promising energy storage devices . Most of the commercial LIBs today are composed of graphitic-based anodes, which are not suitable for high performance applications, such as electric vehicles. In this context, there is an increased interest in the development of novel anode materials, with enhanced kinetics. Such an electrode with enhanced capabilities could be TiO2 nanotube arrays (NTAs). In this paper, anatase TiO2 NTAs were prepared by anodization of a Ti foil in the solution of NH4F in glycerol at the voltage of 45 V and subsequent annealing at 400oC. The presence of anatase TiO2 was confirmed by Raman spectroscopy and the morphology was observed by scanning electron microscopy (SEM), while the electrochemical insertion of Liion in nanotubes was studied by means of cyclic voltammetry (CV) and galvanostatic (GS) charge-discharge experiments by exposing the electrode to the 1M solution of LiClO4 in propylene carbonate. The CV response was fast at all scan rates, up to 50 mV·s-1 , with characteristic Ti4+/Ti3+ redox peaks. The Ti/TiO2 NTAs electrode was GC cycled at different current densities (in orders 100, 50, 25 and again 100 µA·cm-2 ) at room temperature. After the initial 50 cycles the insertion/extraction capacity amounted 191.1/170.1 mAh·g-1 . By decreasing the current density, capacity significantly rises to 268.4/243.3 and 347.8/312.3 mAh·g-1 at 50 and 25 µA·cm-2 , respectively. After the last cycle at 100 µA·cm-2 , capacity amounts 188.9/168.1 mAh·g-1 , which is about 99% of the initial capacity. The diffusion coefficient of Li-ion was calculated to be 7.06·10-16 cm2 ·s-1 during deintercalation and 8.16·10-16 cm2 ·s-1 during intercalation.Twentieth Young Researchers’ Conference - Materials Science and Engineering: Program and the Book of Abstracts; November 30 – December 2, 2022, Belgrade, Serbi

Thin film deposition of multilayers on silicon substrate laser pre-patterned

In scientific and commericial needs, there was a great demand for the modification of biomaterials that would replace damaged tissue in the body. Today, titanium alloys are mostly used for these purposes in combination with metals of similar physicochemical properties. In this context, there is an increased interest in the development of novel biocompatible materials with enhanced surface interface. The experimental results of a Ti/Zr/Ti thin film system deposited on a substrate pre-patterned by a dynamic femtosecond laser are presented. Surface pattering with micrometre characteristics in the form of spikes is being investigated in order to generate arrayed surface patterns for biomedical pruposes. Femtosecond laser pulses were used to acquire black silicon surfaces adorned with conical structures under 0,65 bar in SF6 ambient pressure. The silicon surface contains high aspect ratio spikes with conical morphologies of about 2μm, 400 angle opening, and 13·106 cm-2 density that is roughly uniform over the treatment area. Ion sputtering was employed on sech a prepared surface to make a unique composite thin film composed of two layers of Ti and a subsurface layer of Zr. The deposited Ti/Zr/Ti cpomiste has a thickness of 400 nm. The composition and surface morphology were evaluated using FESEM-EDS and XPS methods. Transmission electron spectroscopy and energy dispersive X-ray spectroscopy demonstrated that post-deposition of Ti/Zr/Ti over Si laser-patterned resulted in diffusion of Ti and Zr layers.Twenty-First Young Researchers’ Conference - Materials Science and Engineering: Program and the Book of Abstracts; November 29 – December 1, 2023, Belgrade, Serbi

Characterization and hydrogen evolution on Pt/nanoplatelets

Finding suitable catalysts for hydrogen evolution reaction (HER) is key for economic production of hydrogen for use in fuel cells. Reducing the amount of expensive noble metals that are used is one of the ways for obtaining such catalysts. Various combinations of different noble metals and various carbon supports have been studied. In this work nanoplatelets (GNP) was used as a support and on it Pt nanoparticles were electrochemically deposited in sub monolayer nanoislands. Obtained Pt/GNP electrode was characterized by X ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) while its electrocatalytic activity was investigated by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and chronoamperometry . XPS analysis showed that the atomic percentages of Pt in Pt/GNP was 1.3% for electhrochemical deposition and 0.3% for spontaneous deposition, respectively. SEM micrographs of Pt/GNP electrode surface showed that Pt nanoparticles occupy mostly the edges GNP support, while elemental maping confirms the distribution of Pt, C and O over the surface of the electrode. Pt/GNP electrode has shown remarkably good performance for HER reaction in 0.5 M H2SO4 acid solution. Outstanding HER activity was achieved, showing the initial potential close to the equilibrium potential for HER and of -0.003 V and a low Tafel slope of about -30 mV/dec. The chronoamperometric measurement performed over 180 min for hydrogen evolution at the constant potential indicates good stability and durability.Twenty-First Young Researchers’ Conference - Materials Science and Engineering: Program and the Book of Abstracts; November 29 – December 1, 2023, Belgrade, Serbi

Photocatalytic activity of ZnO-PEO composites

The removal of organic pollutants from wastewater is very important for environmental protection. During the years different methods have been developed and applied on wastewater treatment. Between those methods a heterogeneous photocatalysis has received extensive attention since it allows a complete mineralization of pollutants. ZnO-based materials has established role in heterogeneous photocatalysis. However, major drawback of ZnO is a band energy gap of 3.37 eV (368 nm) which restricts the material to absorb only UV light. Since sunlight is a source of clean and cheap energy, where UV light makes no more than 3–5% while visible light is about 45% of the total sunlight, it is highly desirable to synthesize ZnO-based materials capable for visible light photocatalysis. To modify the optical absorption properties and improving the visible light photocatalytic activity of ZnO materials several approaches have been applied: (1) metal ion doping, (2) nonmetal doping, (3) defect induced doping, (4) surface sensitization of ZnO particles to extend the spectral response into the visible region, (5) band gap modification by creation of oxygen vacancies and oxygen sub-stoichiometry, etc. In this study, ZnO powder with nanospherical morphology was synthesized by microwave processing. In the continuation, the synthesized powder was used for preparation of composites with polyethylene oxide (PEO). PEO powders with three different molecular mass (200.000, 600.000 and 900.000) were used for composites preparation. The phase purity and crystal structure of the composites were investigated by X-ray diffraction and Raman spectroscopy. The particles morphology and size distributions were studied by FE–SEM and laser diffraction particle size analyzer, respectively. The optical properties were studied using UV–Vis diffuse reflectance and photoluminescence spectroscopy. The photocatalytic activity of ZnO-PEO composites was examined via decomposition of methylene blue (MB) under direct sunlight irradiation. A large efficiency of MB degradation was found after 6 h of irradiation. An enhanced optical and photocatalytical properties of ZnO-PEO composites were attributed to: (1) lattice defects introduced in crystal structure of ZnO by fast microwave processing, and (2) surface sensitization by polyethylene oxide (PEO)

Zinc oxide-based materials with enhanced sunlight-driven photo- and photo-electro-catalytic activity

Current trend in photocatalysis is to develop efficient semiconductors which can be activated by absorbing sunlight. Which wavelength of sunlight will be absorbed depends on the semiconductor band gap; semiconductors with a wide band gap (> 3 eV) can absorb only UV light (5% of sunlight), while those with a narrow band gap (< 3 eV) can be activated by visible light (45% of sunlight). Zinc oxide (ZnO) is promising semiconductor with band gap of 3.37 eV. Various approaches have been applied to modify its optical properties, for example: incorporation of different metal and nonmetal ions or defects into the crystal structure, particles’ surface sensitization or hydrogenation. In this study, we examined the influence of different defects present in ZnO particles on their photo- and photo-electro-catalytic properties. Processing of ZnO particles were carried out in order to introduce: (1) lattice defects, through microwave procedure, (2) surface defects, through mechanical activation, and (3) surface defects, trough composite with polyethylene oxide. Synthesized particles were characterized by XRD, FESEM, laser diffraction particle size analyzer, Raman, UV-Vis diffuse reflectance and photoluminescence spectroscopy. The results of achieved photo- and photo-electro-catalytic tests indicate that both, structural and surface, defects enhanced sunlight-driven activity of ZnO particles

Team-Arbeit, eine unbedingte Notwendigkeit in der Medizin und Stomatologie

U svom radu autori naglašavaju potrebu i neophodnost timskog rada, koji postaje jedini način suvremene brige o zdravlju osobe koja nam je povjerena. U današnjoj humanoj patologiji sve češće susrećemo oboljenja koja ne može rješavati i liječiti jedan stručnjak, ma kako bio stručan. U vrijeme kad se svakih desetak godina broj pretraga udvostručuje, jedino rad više stručnjaka sub- ili superspecijalista može biti punovrijedan i koristan za bolesnika. Danas, kad patologijom razvijenih zemalja dominiraju malformacije, neophodno je obraditi bolesnika i doći do ispravne dijagnoze i genetske prognoze radom stručnjaka više medicinskih profila. Autori iznose primjer triju bolesnika iz svoje prakse kojima je postavljena ispravna dijagnoza i dana moguća terapija veoma kasno. Majka, koja je kao i njen sin, nosila sliku kleidokranijalne dizostoze, bila je upoznata s genetskim značenjem svoje bolesti tek u tridesetoj godini svoga života. Na temelju svojih primjera, autori plediraju za timski rad kao jedini način vrijednog stručnog rada, kojim će se najviše pomoći bolesniku.In their report the authors emphasize the necessity and urgency of team work which they consider to be the best possible way for the medical care of patient\u27s health under the treatment. The contemporary human pathology is full of diseases which can\u27t be successfully treated only by one expert, regardless of high qualities which he can possess from his branch of medicine, in the time when the number of necessary laboratory examinations increases every minute, only the team work of specialists from different branches of medicine can establish the right diagnosis and give the best in the therapy and treatment of a patient. Nowadays, when the pathology of developed countries is dominated by malformations, the team work is indisputable. Not only diagnosis and treatment, but also genetic aspect of an affected person may be solved in that way. From their routine work, the authors present three patients in the cases of which the exact diagnosis and the possible therapy were determined very late. One mother, for example, who showed the clinical picture of cleidocranial disostosis as well as her son, was acquainted with the genetic importance and prognosis of her disease only in her thirties. On the basis of their experience the authors plead for the team work as the only way for a valuable and successful professional work in the desire to help the patient as much as possible.Die Autoren betonen die unbedingte Notwendigkeit einer Team-Arbeit, da diese den erfolgreichsten Weg zur zeitgemässen Gesundheitsfürsorge darstellt. In der humanen Pathologie begegnen uns immer häufiger Erkrankungen wo ein einzelner Fachmann, sei er auch der beste, nicht genügt. Da sich jede zehn Jahre die Untersuchungsverfahren verdoppeln, können heutzutage nur mehrere Sub- oder Superspezialisten die Arbeit zum Wohle der Patienten bewältigen. In der Pathologie der entwickelten Länder dominieren Malformationen, was für die Diagnose und genetische Prognose mehrere medizinische Profile erfordert. Es werden drei Patienten beschrieben bei denen die richtige Diagnose und wirksame Therapie zu spät kam. Eine Mutter und ihr Sohn mit cleidokranialer Disostosis war mit der genetischen Bedeutung ihrer Erkrankung erst im 30. Lebensjahr bekannt gemacht. Aufgrund ihrer Erfahrungen beantragen die Autoren die Team-Arbeit als einzige vollwertige und nützliche Facharbeit

Uticaj insekticida na poljsku klijavost različito dorađenog semena šećerne repe

A three-year field study was carried out to determine the effects of different methods of seed processing with insecticides on the germinability of sugar beet seeds in the field. A two-factorial trial was used to study encrusted, mini pelleted, pelleted and technologically processed seed. The lowest field germinability was obtained using technologically processed seeds, proving that not even the smallest insecticide doses should be applied to bare sugar beet seeds. In our country's climatic conditions, the highest field germinability will be obtained with encrusted seed, the difference being significant relative to mini pelleted and pelleted seed, and highly significant compared with technologically processed seed.Trogodišnjim poljskim ogledom ispitivani su različiti načini dorade semena sa insekticidom Furadan 35-ST na poljsku klijavost semena. Ispitivano je inkrustirano seme, mini pilirano seme, pilirano seme i tehnički dorađeno seme. Najmanja poljska klijavost bila je kod tehnički dorađenog semena sa smanjenom dozom insekticida. Najveća poljska klijavost ostvarena je kod inkrustriranog semena. U sušnim godinama postojala je opravdana razlika između inkrustiranog semena i piliranog semena. Između mini piliranog i piliranog semena nije bilo značajnih razlika, jer se takvi načini obrade semena vrlo malo razlikuju u prečniku pilete, a krupnoća semena je ista. Kada je izvođen ogled, postojale su opravdane razlike između godina, što znači da je poljska klijavost analizirana u različitim klimatskim godinama suvog ratarenja. Svi načini dorade semena tretirani su insekticidom, jer to traži današnja moderna proizvodnja semena šećerne repe