37 research outputs found

    Optimization of hydrothermal carbonization process of grape pomace and application of obtained hydrochar

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    Predmet ovog rada je razvoj i optimizacija procesa hidrotermalne karbonizacije komine grožđa i ispitivanje mogućnosti upotrebe dobijene hidročađi kao adsorbensa olova iz vodenih rastvora. U cilju optimizacije procesa, ispitan je uticaj reakcione temperature na transformaciju biomase, primenom različitih fizičko-hemijskih metoda karakterizacije dobijenih proizvoda karbonizacije na 180, 200 i 220 °C. Hidrotermalno indukovane strukturne promene u dobijenim hidročađima su okarakterisane ispitivanjem fizičko-hemijskog sastava, gorivnih karakteristika, kao i primenom termogravimetrijske, morfološke i spektroskopske analize, dok je u procesnim vodama određen sadržaj neorganskih elemenata, urađena spektroskopska analiza, analiza sadržaja pojedinačnih organskih komponenti i ispitan antioksidativni potencijal. Dobijeni rezultati su pokazali da između dobijenih hidročađi postoje bitne strukturne razlike. Utvrđeno je da hidrotermalna degradacija hemiceluloze i celuloze, uzrokovana povećanjem temperature karbonizacije u najvećoj meri indukuje strukturne promene biomase tokom konverzije. Hidročađ koja poseduje značajan energetski potencijal, povećan sadržaj ugljenika i aromatičnost, kao i mogućnost re-adsorpcije pojedinih neorganskih elemenata dobijena je karbonizacijom na 220 °C. Takođe, povećanje reakcione temperature dovodi do porasta sadržaja fenola, polifenolnih jedinjenja i organskih molekula u procesnim vodama, dok istovremeno uzrokuje opadanje antioksidativne aktivnosti, ukupnog sadržaja antocijana i organskih kiselina. Mogućnost upotrebe hidročađi kao biosrbenta ispitana je sa aspekta adsorpcije Pb2+ jona iz vodenih rastvora. Kako bi se izabrao uzorak sa najboljim adsorpcionim kapacitetom izvršena su preliminarna ispitivanja procesa adsorpcije Pb2+ jona primenom hidročađi dobijenih na tri pomenute reakcione temperature. Dobijeni rezultati su ukazali da hidročađ dobijena na 220 °C pokazuje najbolji adsorpcioni kapacitet (27,8 mg/g), pa je stoga ova hidročađ izabrana za detaljna ispitivanja procesa adsorpcije Pb2+ jona...The subject of this work was the development and optimization of hydrothermal carbonization of grape pomace and investigation of potential applications of the obtained hydrochar as adsorbent of lead from aqueous solutions. In order to optimize the process, influence of the reaction temperature on transformation of biomass was investigated using different physico-chemical characterization methods of the products obtained at 180, 200 and 220 °C. Hydrothermal induced structural changes in hydrochars were elucidated by examination of physico-chemical composition, fuel characteristics, using thermogravimetric, morphological and spectroscopic analysis. IR spectroscopy, analysis of inorganic, as well as organic compounds, and antioxidant assays, were used for process waters characterization. The results showed significant structural differences between the obtained products. It has been found that degradation of hemicellulose and cellulose, caused by temperature increase, governs the most significant structural changes in biomass during carbonization. The formation of hydrochar with significant energy potential, increased carbon content and the best adsorption ability, but decreased H/C ratio was achieved at 220 °C. Also, at higher temperature an increase in total phenolic and organic content in process waters was observed, while total antioxidative capacity, anthocyanin and organic acid content simultaneously decreased. Application of the obtained hydrochars was tested via adsorption of Pb2+ ions from aqueous solution. In order to select material with the best adsorption ability, preliminary studies of Pb2+ sorption using hydrochars obtained at three aforementioned reaction temperatures were performed. Obtained results indicated that hydrochar produced at 220 °C exhibited the best adsorption potential (27.8 mg/g), and therefore this sample was chosen for further investigations of Pb2+ removal..

    Plesni i mikotoksini u zrnu kukuruza posle berbe

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    Incidence of toxigenic fungi (molds) and concentration of mycotoxin aflatoxin B1 (AFB1), deoxynivalenol (DON), zearalenone (ZON) and fumonisin (FB1) were studied in the maize grains collected immediately after harvesting in 2012. A total of 29 maize samples were analyzed and the highest incidence was determined for fungal species of Rhizopus (56.41%), Aspergillus (43.66%) and Fusarium (14.97%) genera. Significantly lower incidence was obtained for species of genus Penicillium (3.31%), and especially for species of genera Acremonium (1.38%), Alternaria (0.75%) and Cladosporium (0.14%). Among toxigenic fungi Aspergillus flavus (36.69%) was the most common species of Aspergillus genus, whereas the Fusarium verticillioides with 14.69% of incidence was the predominant species of Fusarium genus. In all studied maize samples, the presence of AFB1, ZON and FB1 mycotoxins was established, except for DON which was established in 75.86% samples. AFB1 was detected in average concentration of 13.95 μg kg-1 for 44.83% of samples, and average concentration higher than 40 μg kg-1 for 55.17% of samples. The average concentrations of DON which was detected was 235 μg kg-1, while it was 98.38 μg kg-1 and 3590 μg kg-1 for the presence of ZON and FB1, respectively. Moderate positive correlation was obtained between concentrations of AFB1 and FB1 (r=0.35), while weak positive correlation was established between concentrations ZON and DON (r=0.02).Učestalost toksigenih gljiva (plesni) i koncentracija mikotoksina aflatoksina B1 (AFB1), deoksinivalenola (DON), zearalenona (ZON) i fumonizina B1 (FB1) je proučavana u uzorcima zrna kukuruza prikupljenim odmah posle berbe u 2012. godini. U ispitivanih 29 uzoraka najveću zastupljenost imaju vrste iz rodova Rhizopus (56,41%), Aspergillus (43,66%) i Fusarium (14,97%). Značajno niža učestalost ustanovljena je za vrste roda Penicillium (3.31%), a posebno za vrste iz rodova Alternaria (0,75%) i Cladosporium (0,14%). Među toksigenim vrstama, A. flavus (36,69%) je bila najučestalija vrsta iz roda Aspergillus, dok je F. verticillioides sa prisustvom od 14,69% bila dominantna vrsta roda Fusarium. U svim ispitivanim uzorcima kukuruza ustanovljeno je prisustvo mikotoksina AFB1, ZON-a i FB1 (100%), osim DON-a koji je bio prisutan u 75,86% uzoraka. AFB1 je detektovan u prosečnoj koncentraciji od 13,95 μg kg-1 u 44,83% uzoraka i u prosečnoj koncentraciji od više od 40 μg kg-1 u 55,17% uzoraka. Prosečna koncentracija DON-a je bila 235 μg kg-1, ZON-a 98,38 μg kg-1 i FB1 3590 μg kg-1. Srednja pozitivna korelacija ustanovljena je između koncentracija AFB1 i FB1 (r=0,35), dok je slaba pozitivna korelacija utvrđena između koncentracija ZON-a i DON-a (r=0,02)

    EFFECT OF ANTIMONY DOPING ON PROPERTIES OF BARIUM TITANATE CERAMICS

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    Nanopowders of pure and antimony doped barium titanate were synthesized by polymeric precursors method. Sintering was performed at 1300 oC for 8 h. XRD analysis showed formation of cubic crystal structure in all nanopowders and tetragonal in ceramics. The influence of antimony concentration on structure change and microstructure development was analyzed. The significant dielectric properties modification as a consequence of antimony doping was noticed. The electrical resistivity measurements pointed out that antimony concentration influenced on materials change from insulator to semiconductor

    The effects of the „Stomp“ herbicide application on the microbial prevalence in the soil.

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    Agricultural production has benefited a lot from herbicides; however, the use of herbicides caused many environmental problems. Herbicide application can affect the biodiversity of an ecosystem by killing non-target organisms. Microorganisms in the soil are important factors for plant growth; they represent the biological factor of soil fertility. Herbicides can have a beneficial effect on the development of some microorganisms and a negative on others, leading to depletion of microbial diversity in soil. The objective of this work is to determine microbial activity in the soil and to isolate herbicide-resistant bacteria after the use of the “Stomp” herbicide. Agar plate method was used for the determination of microbial prevalence in the soil. The results showed an increase in the total number of bacteria, ammonifiers, fungi, and actinomycetes. Nine isolates, mostly Gram-positive spore- forming rods, showed an ability to grow in the mineral salt medium with different concentrations of “Stomp” herbicide. Isolates G1/1 and G1/2, showed high level of tolerance at the initial pendimethalin concentration of 25 mg/l. Those isolates have the potential to be used to decontaminate herbicide affected ecosystems

    Assessment of computed tomography simulators used in radiotherapy treatment planning in Serbia, Croatia, and Bosnia and Herzegovina

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    The purpose of this work was to evaluate computed tomography simulators used in radio-therapy treatment planning in Serbia, Croatia, and Bosnia and Herzegovina. A survey of quality assurance programmes of 24 computed tomography simulators in 16 facilities was conducted. A dedicated CT-to-ED phantom was scanned at 120 kV and 140 kV, to obtain CT-to-ED conversion curves as well as CTDIvol. Thoracal phantoms were scanned in the standard and extended field of view to evaluate the dosimetric effect on treatment planning and delivery. The mean age of the measured scanners was 5.5 years. The mean water HU value was –6.5 (all scanners, all voltages) and air HU value was –997. Extended field of view computed tomography data differ from the standard field of view and differences between conversion curves have significant dosimetric impact. The CTDI data showed a large range of values between centers. Better quality assurance of computed tomography simulators in all countries is recommended. The CT-to-ED curve could be used as default at one voltage and per manufacturer. Extended field of view imaging can be used, but treatment planning should be avoided in the regions out of the standard field of view

    2015/16 seasonal vaccine effectiveness against hospitalisation with influenza a(H1N1)pdm09 and B among elderly people in Europe: Results from the I-MOVE+ project

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    We conducted a multicentre test-negative caseâ\u80\u93control study in 27 hospitals of 11 European countries to measure 2015/16 influenza vaccine effectiveness (IVE) against hospitalised influenza A(H1N1)pdm09 and B among people aged â\u89¥ 65 years. Patients swabbed within 7 days after onset of symptoms compatible with severe acute respiratory infection were included. Information on demographics, vaccination and underlying conditions was collected. Using logistic regression, we measured IVE adjusted for potential confounders. We included 355 influenza A(H1N1)pdm09 cases, 110 influenza B cases, and 1,274 controls. Adjusted IVE against influenza A(H1N1)pdm09 was 42% (95% confidence interval (CI): 22 to 57). It was 59% (95% CI: 23 to 78), 48% (95% CI: 5 to 71), 43% (95% CI: 8 to 65) and 39% (95% CI: 7 to 60) in patients with diabetes mellitus, cancer, lung and heart disease, respectively. Adjusted IVE against influenza B was 52% (95% CI: 24 to 70). It was 62% (95% CI: 5 to 85), 60% (95% CI: 18 to 80) and 36% (95% CI: -23 to 67) in patients with diabetes mellitus, lung and heart disease, respectively. 2015/16 IVE estimates against hospitalised influenza in elderly people was moderate against influenza A(H1N1)pdm09 and B, including among those with diabetes mellitus, cancer, lung or heart diseases

    Optimization of hydrothermal carbonization process of grape pomace and application of obtained hydrochar

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    Predmet ovog rada je razvoj i optimizacija procesa hidrotermalne karbonizacije komine grožđa i ispitivanje mogućnosti upotrebe dobijene hidročađi kao adsorbensa olova iz vodenih rastvora. U cilju optimizacije procesa, ispitan je uticaj reakcione temperature na transformaciju biomase, primenom različitih fizičko-hemijskih metoda karakterizacije dobijenih proizvoda karbonizacije na 180, 200 i 220 °C. Hidrotermalno indukovane strukturne promene u dobijenim hidročađima su okarakterisane ispitivanjem fizičko-hemijskog sastava, gorivnih karakteristika, kao i primenom termogravimetrijske, morfološke i spektroskopske analize, dok je u procesnim vodama određen sadržaj neorganskih elemenata, urađena spektroskopska analiza, analiza sadržaja pojedinačnih organskih komponenti i ispitan antioksidativni potencijal. Dobijeni rezultati su pokazali da između dobijenih hidročađi postoje bitne strukturne razlike. Utvrđeno je da hidrotermalna degradacija hemiceluloze i celuloze, uzrokovana povećanjem temperature karbonizacije u najvećoj meri indukuje strukturne promene biomase tokom konverzije. Hidročađ koja poseduje značajan energetski potencijal, povećan sadržaj ugljenika i aromatičnost, kao i mogućnost re-adsorpcije pojedinih neorganskih elemenata dobijena je karbonizacijom na 220 °C. Takođe, povećanje reakcione temperature dovodi do porasta sadržaja fenola, polifenolnih jedinjenja i organskih molekula u procesnim vodama, dok istovremeno uzrokuje opadanje antioksidativne aktivnosti, ukupnog sadržaja antocijana i organskih kiselina. Mogućnost upotrebe hidročađi kao biosrbenta ispitana je sa aspekta adsorpcije Pb2+ jona iz vodenih rastvora. Kako bi se izabrao uzorak sa najboljim adsorpcionim kapacitetom izvršena su preliminarna ispitivanja procesa adsorpcije Pb2+ jona primenom hidročađi dobijenih na tri pomenute reakcione temperature. Dobijeni rezultati su ukazali da hidročađ dobijena na 220 °C pokazuje najbolji adsorpcioni kapacitet (27,8 mg/g), pa je stoga ova hidročađ izabrana za detaljna ispitivanja procesa adsorpcije Pb2+ jona...The subject of this work was the development and optimization of hydrothermal carbonization of grape pomace and investigation of potential applications of the obtained hydrochar as adsorbent of lead from aqueous solutions. In order to optimize the process, influence of the reaction temperature on transformation of biomass was investigated using different physico-chemical characterization methods of the products obtained at 180, 200 and 220 °C. Hydrothermal induced structural changes in hydrochars were elucidated by examination of physico-chemical composition, fuel characteristics, using thermogravimetric, morphological and spectroscopic analysis. IR spectroscopy, analysis of inorganic, as well as organic compounds, and antioxidant assays, were used for process waters characterization. The results showed significant structural differences between the obtained products. It has been found that degradation of hemicellulose and cellulose, caused by temperature increase, governs the most significant structural changes in biomass during carbonization. The formation of hydrochar with significant energy potential, increased carbon content and the best adsorption ability, but decreased H/C ratio was achieved at 220 °C. Also, at higher temperature an increase in total phenolic and organic content in process waters was observed, while total antioxidative capacity, anthocyanin and organic acid content simultaneously decreased. Application of the obtained hydrochars was tested via adsorption of Pb2+ ions from aqueous solution. In order to select material with the best adsorption ability, preliminary studies of Pb2+ sorption using hydrochars obtained at three aforementioned reaction temperatures were performed. Obtained results indicated that hydrochar produced at 220 °C exhibited the best adsorption potential (27.8 mg/g), and therefore this sample was chosen for further investigations of Pb2+ removal..
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