101 research outputs found
Invasiveness of allochthonous macroinvertebrate and fish species of the Danube river
Istraživanje alohtone faune makroinvertebrata i riba Dunava raÄeno je na osnovu
uzoraka prikupljenih tokom avgusta i septembra 2007. i 2013. godine. U radu je dat
detaljan pregled alohtone komponente sa tri aspekta: taksonomska i zoogeografska
analiza, testiranje indeksa za ocenu pritisaka i procena invazibilnosti podruÄja, kao i
korelacija nivoa bioloÅ”kih invazija i izabranih parametara pritiska. Posebno je obraÄen
predlog mera za smanjenje stope unosa i Å”irenja ranije veÄ introdukovanih alohtonih
vrsta, kao i za smanjenje pritiska.
Analizom materijala zabeležena je 31 alohtona vrsta makroinvertebrata. NajveÄi
broj vrsta pripada rakovima ā grupa Malacostraca, poreklom iz Ponto-kaspijskog
regiona. Analizom uzoraka ribljih zajednica ukupno je registrovano 13 alohtonih vrsta
poreklom iz tri biogeografske regije Äiji su predstavnici podjednako zastupljeni: Pontokaspijske,
Severno-ameriÄke i Azijske.
Razmatranjem naÄina unosa i sredstava kojima su vrste raÅ”irene van granica
nativnog areala, možemo konstatovati da je za mali broj vrsta makroinvertebrata
dokazano da je u Ŕirenju areala bilo neposrednog uticaja antopogene aktivnosti, dok je
za disperziju riba antropogena aktivnost dominantna.
Prisustvo alohtone faune po sektorima Dunava je ujednaÄeno i za
makroinvertebrate i za ribe, sa znaÄajnim optereÄenjem alohtonom faunom u gornjem i
srednjem delu toka. Osam vrsta makroinvertebrata i sedam vrsta riba ima visok
potencijal za Ŕirenjem areala, uspostavljanjem populacija i visok potencijal da
prouzrokuje ekoloÅ”ke i negativne socio-ekonomske usled Äega su stavljene na Crnu
listu.
Visok nivo bioloÅ”kog zagaÄenja procenjen je za sedam vrsta makroinvertebrata i
tri vrste riba: Chelicorophium curvispinum, Corbicula fluminea, Dikerogammarus
villosus, Dreissena polymorpha, Dreissena bugensis, Pectinatella magnifica,
Sinanodonta woodiana, Carassius gibelio, Lepomis gibosus i Neogobius melanostomus.
Na osnovu ukupne ocene invazibilnosti podruÄja glavnog toka Dunava u Srbiji
dobijene na osnovu izabranih parametara za koje se pretpostavlja da doprinose
intenzitetu bioloÅ”kih invazija možemo zakljuÄiti da je sektor od Beograda do brane
āÄerdap Iā najosetljiviji na bioloÅ”ko zagaÄenje, kao i lokalitet nizvodno od Novog
Sada...Investigation of allochthonous macroinvertebrates and fish species of the
Danube River was based on samples collected during August and September 2007 and
2013. Detailed overview of allochthonous species was presented regarding: taxonomic
and zoogeographic analyses, testing of indices and risk assessment procedure and
invasiveness of the area, as well as correlation of the level of biological invasions and
selected parameters of pressures. Further steps for reduction of new invasions,
spreading already established allochthonous species and reduction of pressures were
pointed separately.
In total, 31 allochthonous macroinvertebrate species were registered. The most
numerous were Crustaceans ā group Malacostraca, originate from Ponto-caspian region.
Among fish, 11 allochthonous species were detected from three different biogeographic
region: Ponto-caspian, North American and Asian.
Regarding the mode of arrival and pathway we may conclude that the large
majority of non-indigenous fish species and only few macroinvertebrate species were
introduced as a direct effect of human intervention.
Analysis of allochthonous fauna showed that Upper and Middle sectors of the
Danube are most affected. Due to high potential to spread, high potential for
establishment in new environment and high potential to cause ecological and negative
socio-economic impacts, eight macroinvertebrate and seven fish species were specified
as Black list alien species.
For seven macroinvertebrate and three fish species high level of Biological
contamination Index was estimated: Chelicorophium curvispinum, Corbicula fluminea,
Dikerogammarus villosus, Dreissena polymorpha, Dreissena bugensis, Pectinatella
magnifica, Sinanodonta woodiana, Carassius gibelio, Lepomis gibosus i Neogobius
melanostomus.
Based on the overall analyses of selected parameters assumed that are important
for intensity of biological invasions, we may conclude that part of the Danube stretch
between Belgrade and Iron Gate I dam, as well as locality downstream Novi Sad are
most affected regarding biological contamination..
Multi-objective fuzzy optimization of sizing and location of piezoelectric actuators and sensors for vibration control based on the particle swarm optimization technique (part 1: Theoretical model)
OdreÄivanje veliÄine i položaja piezoelektriÄnih aktuatora i senzora za aktivno upravljanje vibracijama savitljivih struktura obiÄno je bazirano na maksimalnoj efikasnosti upravljanja i postizanja maksimalnog izlaza za modove vibracija od interesa. Integracija piezoelektriÄnih delova utiÄe na masu i dinamiÄke performanse baziÄne strukutre. Ovo je prvi deo istraživanja koje predstavlja teorijski razvoj viÅ”eciljne fazi optimizacione tehnike za odreÄivanje položaja i veliÄine piezoelektriÄnih aktuatora i senzora na tankozidnoj kompozitnoj gredi. Kriterijumi optimizacije za odreÄivanje optimalne veliÄine i položaja piezoelektriÄnih aktuatora i senzora zasnivaju se na stepenu upravljivosti upravljanih modova. Procedura optimizacije obuhvata ograniÄenje promene prvobitnih dinamiÄkih karakteristika i ograniÄenje u porastu mase. Pseudociljna funkcija, zasnovana na teoriji fazi skupova, daje izraz za globalnu ciljnu funkciju eliminiÅ”uÄi upotrebu težinskih koeficijenata i kaznenih funkcija. Optimizacija rojem Äestica je upotrebljena za nalaženje optimalne konfiguracije.Sizing and location of the piezoelectric actuators and sensors for vibration control of flexible structures is usually based on maximum control effectiveness and achieving the maximum output for the vibration in the modes of interests. Integration of piezoelectric patches affects the mass and the original dynamic properties of the parent structure. This is the first part of the two-paper research which presents the theoretical development of the multi-objective fuzzy optimization technique of sizing and location of the collocated piezoelectric actuators and sensors on the thin-walled composite beam. The optimization criteria for the optimal size and location of piezoelectric A/Ss are based on the degree of controllability (DC) for controlled modes. The optimization procedure implies the constraining of the original dynamic properties change and the limitation of the mass increase. A pseudogoal function, derived based on the fuzzy set theory, gives an expression for global objective functions eliminating the use of weighting coefficients and penalty functions. the particle swarm optimization technique is used to find the optimal configuration.
Multi-objective fuzzy optimization of sizing and location of piezoelectric actuators and sensors for vibration control based on the particle swarm optimization technique (part 1: Theoretical model)
OdreÄivanje veliÄine i položaja piezoelektriÄnih aktuatora i senzora za aktivno upravljanje vibracijama savitljivih struktura obiÄno je bazirano na maksimalnoj efikasnosti upravljanja i postizanja maksimalnog izlaza za modove vibracija od interesa. Integracija piezoelektriÄnih delova utiÄe na masu i dinamiÄke performanse baziÄne strukutre. Ovo je prvi deo istraživanja koje predstavlja teorijski razvoj viÅ”eciljne fazi optimizacione tehnike za odreÄivanje položaja i veliÄine piezoelektriÄnih aktuatora i senzora na tankozidnoj kompozitnoj gredi. Kriterijumi optimizacije za odreÄivanje optimalne veliÄine i položaja piezoelektriÄnih aktuatora i senzora zasnivaju se na stepenu upravljivosti upravljanih modova. Procedura optimizacije obuhvata ograniÄenje promene prvobitnih dinamiÄkih karakteristika i ograniÄenje u porastu mase. Pseudociljna funkcija, zasnovana na teoriji fazi skupova, daje izraz za globalnu ciljnu funkciju eliminiÅ”uÄi upotrebu težinskih koeficijenata i kaznenih funkcija. Optimizacija rojem Äestica je upotrebljena za nalaženje optimalne konfiguracije.Sizing and location of the piezoelectric actuators and sensors for vibration control of flexible structures is usually based on maximum control effectiveness and achieving the maximum output for the vibration in the modes of interests. Integration of piezoelectric patches affects the mass and the original dynamic properties of the parent structure. This is the first part of the two-paper research which presents the theoretical development of the multi-objective fuzzy optimization technique of sizing and location of the collocated piezoelectric actuators and sensors on the thin-walled composite beam. The optimization criteria for the optimal size and location of piezoelectric A/Ss are based on the degree of controllability (DC) for controlled modes. The optimization procedure implies the constraining of the original dynamic properties change and the limitation of the mass increase. A pseudogoal function, derived based on the fuzzy set theory, gives an expression for global objective functions eliminating the use of weighting coefficients and penalty functions. the particle swarm optimization technique is used to find the optimal configuration.
Structural adaptation of Salsola soda L. (Chenopodiaceae) from inland and maritime saline area
The microscopic analysis of leaf and stem in two populations of Salsola soda
was carried out in order to examine mechanism of anatomical adaptations to
environmental condition on saline habitats and to determine if there exists a
morpho-anatomical differentiation between populations from maritime and
inland saline area. Analysis included 26 quantitative characters of leaf and
stem. The results showed that both populations exhibited halomorphic and
xeromorphic adaptations, which refered to ecological plasticity and
adaptations of plants to their habitats. Our research also showed that S.
soda had quite a stable morphoanatomical structure, since only quantitative
changes were recorded. [Projekat Ministarstva nauke Republike Srbije, br.
173002
Multi-objective fuzzy optimization of sizing and location of piezoelectric actuators and sensors for vibration control based on the particle swarm optimization technique: Part 2: Numerical analysis
Ovo je drugi deo istraživanja viÅ”eciljne fazi optimizacije veliÄine i položaja piezoelektriÄnih aktuatora i senzora na tankozidnoj kompozitnoj gredi. Prvi rad je fokusiran na teorijskom modelu optimizacione tehnike za optimalno dimenzionisanje i postavljanje piezoelektiÄnih aktuatora i senzora na pametnu strukturu za aktivno upravljanje vibracijama. U ovom delu, biÄe prikazana numeriÄka analiza predstavljene optimizacione tehnike za kompozitnu konzolu sa i bez ograniÄenja u pogledu stepena upravljivosti za rezidualne modove.This is the second part of a two-paper research of the multi-objective fuzzy optimization of sizing and location of the collocated piezoelectric actuators and sensors on the thin-walled composite beam. The first paper is focussed on the theoretical model of a optimization techique for optimal sizing and location of piezoelectric actuators and sensors on a smart structure for active vibration control. In this part, the numerical analysis of the presented optimization technique will be presented for the cantilever composite beam with and without limitations in degrees of controllability (DCs) for residual modes
Multi-objective fuzzy optimization of sizing and location of piezoelectric actuators and sensors for vibration control based on the particle swarm optimization technique: Part 2: Numerical analysis
Ovo je drugi deo istraživanja viÅ”eciljne fazi optimizacije veliÄine i položaja piezoelektriÄnih aktuatora i senzora na tankozidnoj kompozitnoj gredi. Prvi rad je fokusiran na teorijskom modelu optimizacione tehnike za optimalno dimenzionisanje i postavljanje piezoelektiÄnih aktuatora i senzora na pametnu strukturu za aktivno upravljanje vibracijama. U ovom delu, biÄe prikazana numeriÄka analiza predstavljene optimizacione tehnike za kompozitnu konzolu sa i bez ograniÄenja u pogledu stepena upravljivosti za rezidualne modove.This is the second part of a two-paper research of the multi-objective fuzzy optimization of sizing and location of the collocated piezoelectric actuators and sensors on the thin-walled composite beam. The first paper is focussed on the theoretical model of a optimization techique for optimal sizing and location of piezoelectric actuators and sensors on a smart structure for active vibration control. In this part, the numerical analysis of the presented optimization technique will be presented for the cantilever composite beam with and without limitations in degrees of controllability (DCs) for residual modes
The influence of the UV irradiation intensity on photocatalytic activity of ZnAl layered double hydroxides and derived mixed oxides
Layered double hydroxides (LDHs) have been studied to a great extent as environmental-friendly complex materials that can be used as photocatalysts or photocatalyst supports. ZnAl layered double hydroxides and their derived mixed oxides were chosen for the investigation of photocatalytic performances in correlation with the UV intensities measured in the South Pannonia region. Low supersaturation coprecipitation method was used for the ZnAl LDH synthesis. For the characterization of LDH and thermal treated samples powder X-ray diffraction (XRD), scanning electron microscopy (SEM), electron dispersive spectroscopy (EDS), nitrogen adsorption-desorption were used. The decomposition of azodye, methylene blue was chosen as photocatalytic test reaction. The study showed that the ZnAl mixed oxide obtained by thermal decomposition of ZnAl LDH has stable activity in the broader UV light irradiation range characterizing the selected region. Photocatalytic activity could be mainly attributed to the ZnO phase, detected both in LDH and thermally treated samples. The study showed that the ZnAl mixed oxide obtained by the calcination of ZnAl LDH has a stable activity within the measured UV light irradiation range; whereas the parent ZnAl LDH catalyst did not perform satisfactory when low UV irradiation intensity is implied
Fusion excitation function revisited
We report on a comprehensive systematics of fusion-evaporation and/or
fusion-fission cross sections for a very large variety of systems over an
energy range 4-155 A.MeV. Scaled by the reaction cross sections, fusion cross
sections do not show a universal behavior valid for all systems although a high
degree of correlation is present when data are ordered by the system mass
asymmetry.For the rather light and close to mass-symmetric systems the main
characteristics of the complete and incomplete fusion excitation functions can
be precisely determined. Despite an evident lack of data above 15A.MeV for all
heavy systems the available data suggests that geometrical effects could
explain the persistence of incomplete fusion at incident energies as high as
155A.MeV.Comment: 8 pages, 5 figures, contribution to the NN2012 Proceeding
Experimental investigation of spillover effect in system of active vibration control
PiezoelektriÄni aktuatori se uveliko primenjuju za aktivno upravljanje vibracijama na raznim strukturama sa ciljem poveÄanja performansi sistema. Razvijeni sistem aktivnog upravljanja vibracijama se sastoji od aktivnije strukture, kontrolera i visokonaponskih pojaÄivaÄa. U ovom radu, kompozitna greda predstavlja osnovnu strukturu za senzorsku (merne trake) i aktuatorsku (dvoslojni PZT piezoelektriÄni aktuator) platformu. U cilju unapreÄenja dinamiÄkih karakteristika aktivnog sistema vrÅ”ena je promena koeficijenata PID regulatora. Efikasnost sistema aktivnog upravljanja vibracijama za posmatrani mod oscilovanja se može poveÄati promenom koeficijenata PID regulatora, ali u isto vreme moguÄe je naruÅ”iti stabilnost sistema. Nestabilnost sistema je najÄeÅ”Äe uslovljena pojavom 'spillover' efekta. U ovom radu predstavljen je znaÄaj 'spillover' efekta u zatvorenim petljama piezoelektriÄnih aktivnih struktura, kao i znaÄaj promene koeficijenata PID regulatora na stabilnost sistema. Eksperimentalni rezultati sistema aktivnog priguÅ”enja vibracija su predstavljeni u radu i daju jednu od moguÄnosti za poveÄanje stabilnosti upravljanih struktura.Piezoelectric actuators are widely used in structural systems for active vibration control with the aim to enhance the performance of systems. The developed system of active vibration control consists of active structure, controller and high voltage amplifier. In this paper, the composite beam is host structure for sensor platform (strain gages) and actuator platform (dual layer PZT piezoelectric actuator). In order to improve the dynamic characteristics of active system, the coefficients of PID controller are changed. The effectiveness of active vibration control system at mode of interest can be improved with change of PID coefficients, but the stability of system can be reduced. The instability of the active structure is often perturbed by spillover effect. In this paper the importance of considering spillover effects in closed loop of piezoelectric active structures is demonstrated and shown the importance of change the PID coefficients in stability of active vibration control system. Experimental results which correspond to the developed active vibration control system are presented and affirmed stability on proposed active structure
Experimental investigation of spillover effect in system of active vibration control
PiezoelektriÄni aktuatori se uveliko primenjuju za aktivno upravljanje vibracijama na raznim strukturama sa ciljem poveÄanja performansi sistema. Razvijeni sistem aktivnog upravljanja vibracijama se sastoji od aktivnije strukture, kontrolera i visokonaponskih pojaÄivaÄa. U ovom radu, kompozitna greda predstavlja osnovnu strukturu za senzorsku (merne trake) i aktuatorsku (dvoslojni PZT piezoelektriÄni aktuator) platformu. U cilju unapreÄenja dinamiÄkih karakteristika aktivnog sistema vrÅ”ena je promena koeficijenata PID regulatora. Efikasnost sistema aktivnog upravljanja vibracijama za posmatrani mod oscilovanja se može poveÄati promenom koeficijenata PID regulatora, ali u isto vreme moguÄe je naruÅ”iti stabilnost sistema. Nestabilnost sistema je najÄeÅ”Äe uslovljena pojavom 'spillover' efekta. U ovom radu predstavljen je znaÄaj 'spillover' efekta u zatvorenim petljama piezoelektriÄnih aktivnih struktura, kao i znaÄaj promene koeficijenata PID regulatora na stabilnost sistema. Eksperimentalni rezultati sistema aktivnog priguÅ”enja vibracija su predstavljeni u radu i daju jednu od moguÄnosti za poveÄanje stabilnosti upravljanih struktura.Piezoelectric actuators are widely used in structural systems for active vibration control with the aim to enhance the performance of systems. The developed system of active vibration control consists of active structure, controller and high voltage amplifier. In this paper, the composite beam is host structure for sensor platform (strain gages) and actuator platform (dual layer PZT piezoelectric actuator). In order to improve the dynamic characteristics of active system, the coefficients of PID controller are changed. The effectiveness of active vibration control system at mode of interest can be improved with change of PID coefficients, but the stability of system can be reduced. The instability of the active structure is often perturbed by spillover effect. In this paper the importance of considering spillover effects in closed loop of piezoelectric active structures is demonstrated and shown the importance of change the PID coefficients in stability of active vibration control system. Experimental results which correspond to the developed active vibration control system are presented and affirmed stability on proposed active structure
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