Primena numeričkih modela za optimizaciju rada bunarske zaštite eksploatacionih bunara - primer izvorišta Korbovo

Advanced mathematical models of groundwater flow provide exceptional support in designing of new wellheads, but also optimization analyses of the existing groundwater resources management. However, for reliable forecasts their application requires a large data base that may be obtained exclusively through field research. The paper demonstrates the application of advanced mathematical models in an optimization analysis of the wellhead protection system management, with the case study of the wellhead 'Korbovo', at the Danube riverbank. Required field investigations and background data were presented as the basis for the formulation of mathematical model. On the basis of numerical analysis, a solution was proposed for the wellhead protection management, which generates significant energy savings in relation to the existing conditions.Savremeni matematički modeli strujanja podzemnih voda pružaju izuzetnu podršku kod projektovanja novih, ali i kod različitih optimizacija rada postojećih izvorišta podzemnih voda. Međutim, njihova primena u cilju pouzdanih prognoza zahteva obiman fond podataka do kojih se dolazi isključivo terenskim istraživanjima. U radu se demonstrira primena naprednih matematičkih modela u cilju optimizacije rada bunarske zaštite izvorišta podzemnih voda na primeru izvorišta "Korbovo" pored Dunava. U tom smislu, prezentovana su neophodna istraživanja i podloge kao osnova za formiranje matematičkog modela. Na osnovu numeričkih analiza predloženo je rešenje rada bunarske zaštite kojom se ostvaruju značajne energetske uštede u odnosu na postojeće uslove

Primena numeričkih modela za optimizaciju rada bunarske zaštite eksploatacionih bunara - primer izvorišta Korbovo

Advanced mathematical models of groundwater flow provide exceptional support in designing of new wellheads, but also optimization analyses of the existing groundwater resources management. However, for reliable forecasts their application requires a large data base that may be obtained exclusively through field research. The paper demonstrates the application of advanced mathematical models in an optimization analysis of the wellhead protection system management, with the case study of the wellhead 'Korbovo', at the Danube riverbank. Required field investigations and background data were presented as the basis for the formulation of mathematical model. On the basis of numerical analysis, a solution was proposed for the wellhead protection management, which generates significant energy savings in relation to the existing conditions.Savremeni matematički modeli strujanja podzemnih voda pružaju izuzetnu podršku kod projektovanja novih, ali i kod različitih optimizacija rada postojećih izvorišta podzemnih voda. Međutim, njihova primena u cilju pouzdanih prognoza zahteva obiman fond podataka do kojih se dolazi isključivo terenskim istraživanjima. U radu se demonstrira primena naprednih matematičkih modela u cilju optimizacije rada bunarske zaštite izvorišta podzemnih voda na primeru izvorišta "Korbovo" pored Dunava. U tom smislu, prezentovana su neophodna istraživanja i podloge kao osnova za formiranje matematičkog modela. Na osnovu numeričkih analiza predloženo je rešenje rada bunarske zaštite kojom se ostvaruju značajne energetske uštede u odnosu na postojeće uslove

Influence of the twilight period and different sampling methods on catch of Gobiids (Gobiidae) at four locations in the inshore parts of the Danube River

The aim of this work was to compare the efficiency of two different methods for fish sampling and to assess the influence of the twilight period on the catch of gobiids along the Danube River in Serbia. The samplings were performed by electrofishing and beach seining in inshore parts of the Danube River with water depth up to 120 cm at four locations: Novi Sad, Belgrade, Tekija, and Prahovo, in October 2012 and September 2013. At each location, the samplings were performed at 17:30, 18:30, 19:30 and 20:30. Totally, 539 gobiids were caught. The highest number of specimens (218) was registered at Tekija, while lower numbers were registered at Belgrade (192) and Prahovo (117), and only 12 specimens were caught at Novi Sad. The catch of the round goby Neogobius melanostomus and monkey goby Neogobius fluviatilis was more efficient by beach seining than by electrofishing, whereas the catch of the tubenose goby Proterorhinus semilunaris was more efficient by electrofishing. Both methods had similar efficiency in catching the bighead goby Ponticola kessleri and racer goby Babka gymnotrachelus. The species diversity and number of the caught specimens were the highest at 18:30. All five species were recorded at Belgrade, Tekija and Prahovo, while only the monkey goby and racer goby were caught at Novi Sad. The methods used in this study showed good efficiency in catching gobiids, especially at dusk. Even though these methods are difficult to apply in certain habitats, they could be highly relevant in the regular monitoring of gobiids along the inshore parts of rivers

Biometry and diet of Perccottus glenii Dybowski, 1877 found in stagnant water nearby Veliko Gradište (northeastern Serbia)

The aim of this study was to describe biometric and feeding characteristics of highly in-vasive species Perccottus glenii in the investigated locality. A total of 85 fish were elec-trofished in the drainage channel located at the vicinity of Veliko Gradište (northeastern Serbia) and preserved in the alcohol solution. In the laboratory, fish were measured (TL, ± 0.01 mm; W, ± 0.01 g), otholits and digestive tracts were removed for age determination and dietary analysis (stereomicroscope). Biometric analysis included length-frequency distribution using 10 mm class intervals; determination of average length and weight for each age group; lenght-weigth relationship; Fulton’s condition factor. Ingested organisms were identified to the lowest reliable taxonomic level (mainly order) and counted. The respective ranges of TL and W of examined fish were 35-140.7 mm and 0.5-40 g. Length class 70.1-80.0 mm clearly dominated (24%). Four age groups were determined (0+-3+), and their descriptive statistics is presented. The value of allometric coefficient for the length-weight relationship (b= 3.068) indicated isometric growth. Fulton’s condition fac-tor did not differ between age groups. Empty digestive tract was found in 2 specimens. A total of 12 prey categories representing Ephemeroptera, Trichoptera, Odonata, Hemiptera, Chironomidae, Coleoptera, Gastropoda, Hirudinea, Oligochaeta, Gammaraidae, uniden-tified and terrestrial insects were identified in the diet. Generally, the diet is entirely com-posed of aquatic invertebrates, as only one terrestrial insect was found. Obtained results did not show clear difference in diet composition between age groups. However, analysis have shown that the most diverse diet characterize 2+ age. By frequency, the insect larvae were categories with highest participation regardless of age

Efikasnost biofertilizatora na klijavost i prinos kima, anisa i korijandera

Microbiological fertilizers used in this study were: Bacillus subtilis and FZB24 Rhizovital 42 I. In laboratory conditions were tested influence of this preparations on germination energy and total germination of seeds caraway (Carum carvi L.), anise (Pimpinella anisum L.) and coriander (Coriandrum sativum L.). The standard germination of tested plants is determined according to ISTA rules, to four repetitions in plastic boxes under alternating temperatures 20-30 °C, and counts were after 7 and 21 days. Use of the preparation was not significantly increased the germination of tested plants or total germination in caraway and anise, while coriander germination significantly increased for 4,5% using the preparation RhizoVital 42 l Field experiment was set up by randomized block design with three replications. The different times of application of the aforementioned preparations were examined, and their impact on seed yield. The results show that in all three tested plants was more effective was biofertilizer RhizoVital 42 l. The most effective time to apply the tested preparations on coriander is in phase 2-3 leaves, on anise in phase rosette leaf, and on caraway and when 10% of plants began to flourish.Mikrobiološka đubriva koja su korišćena u ovom radu su: Bacillus subtilis FZB24 i Rhizovital 42 I. U laboratorijskim uslovima ispitivan je uticaj preparata na energiju klijanja i ukupnu klijavost semena kima, anisa i korijandera. Standardna klijavost navedenih biljaka određena je prema pravilima ISTA, u četiri ponavljanja u plastičnim kutijama na naizmeničnoj temperaturi 20-30°C, a očitavanja su bila nakon 7 i 21 dan. Primena preparata nije statistički značajno uticala na povećanje energije klijanja ispitivanih biljaka kao ni ukupne klijavosti kod kima i anisa, dok se kod korijandera ukupna klijavost statistički značajno povećala primenom preparata RhizoVital 42 l za 4,5%. Poljski ogled je bio postavljen po metodu slučajnog blok sistema sa tri ponavljanja. Testirano je različito vreme primene ispitivanih preparata, i njihov uticaj na prinos semena. Rezultati pokazuju da je kod sve tri ispitivane biljke efikasniji je bio preparat RhizoVital 42 l. Najefikasnije vreme za primenu ispitivanih preparata kod korijandra je u fazi 2-3 lista., anisa kada su biljke u fazi lisne rozete, a kima kada je 10% biljaka počelo da cveta

Influence of the diel period and different sampling methods on catch of gobiids at four locations in the inshore part of the Danube River

Some recent data show that five gobiid species have spread outside their native range and expanded their distribution area in Serbia along the rivers Danube, Tisza, Sava,and Velika Morava. These are: monkey goby Neogobius fluviatilis, racer goby Neogobius gymnotrachelus, bighead goby Neogobius kessleri,round goby Neogobius melanostomus, and tubenose goby Proterorhinus semilunaris. The aim of this study was to compare the efficiency of two different methods for fish sampling, as well as to assess influence of the diel period on catch of gobiids in the Serbian stretch of the Danube River. During October 2012 and September 2013, the sampling was performed by electrofishing and beach seining in four riverside locations of the Danube River,as follows: at NoviSad (river km 1257), Belgrade(river km 1173),Tekija (river km 956),and Prahovo (river km 862),with the water depth being of up to120cm. At each location,the sampling was performed at 17:30,18:30,19:30 and 20:30. A total of 551 gobies were caught. The highest number of specimens (238) was registered at Tekija,followed by the sites at Belgrade(192) and Prahovo (109), and only 12 specimens caught at NoviSad.The catch of the round goby and monkey goby was more efficient by beach seining than by electrofishing, while the catch of the tubenose goby was more efficient by electrofishing. Both methods had similar efficiency in terms of the catch of the bighead goby and racer goby.The species diversity and the number of caught specimens were the highest at 18:30.All five species were recorded at the sites of Belgrade,Tekija and Prahovo,while only the monkey goby and racer goby were caught at NoviSad. The methods used in this study showed good efficiency in catch of gobiids, especially at dusk. Despite the difficulty in using these methods in certain habitats, we assume that they could be highly relevant in the regular monitoring of gobiids along the inshore parts of the rivers

Influence of the twilight period and different sampling methods on catch of Gobiids (Gobiidae) at four locations in the inshore parts of the Danube River

The aim of this work was to compare the efficiency of two different methods for fish sampling and to assess the influence of the twilight period on the catch of gobiids along the Danube River in Serbia. The samplings were performed by electrofishing and beach seining in inshore parts of the Danube River with water depth up to 120 cm at four locations: Novi Sad, Belgrade, Tekija, and Prahovo, in October 2012 and September 2013. At each location, the samplings were performed at 17:30, 18:30, 19:30 and 20:30. Totally, 539 gobiids were caught. The highest number of specimens (218) was registered at Tekija, while lower numbers were registered at Belgrade (192) and Prahovo (117), and only 12 specimens were caught at Novi Sad. The catch of the round goby Neogobius melanostomus and monkey goby Neogobius fluviatilis was more efficient by beach seining than by electrofishing, whereas the catch of the tubenose goby Proterorhinus semilunaris was more efficient by electrofishing. Both methods had similar efficiency in catching the bighead goby Ponticola kessleri and racer goby Babka gymnotrachelus. The species diversity and number of the caught specimens were the highest at 18:30. All five species were recorded at Belgrade, Tekija and Prahovo, while only the monkey goby and racer goby were caught at Novi Sad. The methods used in this study showed good efficiency in catching gobiids, especially at dusk. Even though these methods are difficult to apply in certain habitats, they could be highly relevant in the regular monitoring of gobiids along the inshore parts of rivers

Electrochemical composite bioceramic coatings based on hydroxyapatite, chitosan and polyvinyl alcohol loaded with gentamicin

Composite bioceramic coatings have been attracting increasing attention of the scientific public in recent decades due to the good potential of their use for medical purposes. The main goal of this scientific research is to show the characterization of the obtained hydroxyapatite (HAP), chitosan (CS) and polyvinyl alcohol (PVA) bioceramic composite coatings loaded with gentamicin (Gent), on titanium (Ti) substrate using the single-step electrophoretic deposition process. Titanium, traditionally used for the purpose of replacing parts of damaged bone tissue, has shown good mechanical properties and biocompatibility through many years of orthopedic practice. Hydroxyapatite provided the HAP/CS/PVA/Gent composite coating with osteoinductivity, while the presence of chitosan and polyvinyl alcohol contributed to its adhesive and mild analgesic properties. The antibacterial agent gentamicin was added to the HAP/CS/PVA composite, which ensured its direct antibacterial effect at the implantation site. The coatings were deposited using the cathodic electrophoretic deposition process, with the Ti plate as the cathode, at a constant voltage of 7V, in the range of the deposition time from 5 to 12 min. To demonstrate the presumed bioactivity, HAP/CS/PVA/Gent coatings were immersed in simulated body fluid (SBF) at 37⁰C for periods of 7 and 14 days. Characterization of HAP/CS/PVA/Gent coatings after immersion was performed through employment of Fourier transform infrared spectroscopy (FTIR), X ray diffraction (XRD), and field emission scanning electron microscopy (SEM) techniques. Antibacterial activity was tested by agar diffusion method on two bacterial strains, Echerichia coli and Staphylococcus aureus with a positive response to both bacterial strains. The final conclusions of this research suggest a good potential for utilization of HAP/CS/PVA/Gent bioceramic composite coating, applied through electrophoretic deposition process on Ti substrate, for medical purposes in the replacement and healing of damaged bone tissue